Merge pull request #20908 from ziglang/reorg-std.debug-again

std.debug: reorg and clarify API goals

9 files changed, 3510 insertions, 3426 deletions

diff --git a/lib/std/debug.zig b/lib/std/debug.zig
index 22a7e551ec..4d3437f665 100644
--- a/lib/std/debug.zig
+++ b/lib/std/debug.zig
@@ -1,16 +1,11 @@
-const std = @import("std.zig");
 const builtin = @import("builtin");
+const std = @import("std.zig");
 const math = std.math;
 const mem = std.mem;
 const io = std.io;
 const posix = std.posix;
 const fs = std.fs;
 const testing = std.testing;
-const elf = std.elf;
-const DW = std.dwarf;
-const macho = std.macho;
-const coff = std.coff;
-const pdb = std.pdb;
 const root = @import("root");
 const File = std.fs.File;
 const windows = std.os.windows;
@@ -18,8 +13,24 @@ const native_arch = builtin.cpu.arch;
 const native_os = builtin.os.tag;
 const native_endian = native_arch.endian();
 
+pub const MemoryAccessor = @import("debug/MemoryAccessor.zig");
 pub const Dwarf = @import("debug/Dwarf.zig");
+pub const Pdb = @import("debug/Pdb.zig");
+pub const SelfInfo = @import("debug/SelfInfo.zig");
+
+/// Unresolved source locations can be represented with a single `usize` that
+/// corresponds to a virtual memory address of the program counter. Combined
+/// with debug information, those values can be converted into a resolved
+/// source location, including file, line, and column.
+pub const SourceLocation = struct {
+    line: u64,
+    column: u64,
+    file_name: []const u8,
+};
 
+/// Deprecated because it returns the optimization mode of the standard
+/// library, when the caller probably wants to use the optimization mode of
+/// their own module.
 pub const runtime_safety = switch (builtin.mode) {
     .Debug, .ReleaseSafe => true,
     .ReleaseFast, .ReleaseSmall => false,
@@ -46,39 +57,6 @@ pub const sys_can_stack_trace = switch (builtin.cpu.arch) {
     else => true,
 };
 
-pub const LineInfo = struct {
-    line: u64,
-    column: u64,
-    file_name: []const u8,
-
-    pub fn deinit(self: LineInfo, allocator: mem.Allocator) void {
-        allocator.free(self.file_name);
-    }
-};
-
-pub const SymbolInfo = struct {
-    symbol_name: []const u8 = "???",
-    compile_unit_name: []const u8 = "???",
-    line_info: ?LineInfo = null,
-
-    pub fn deinit(self: SymbolInfo, allocator: mem.Allocator) void {
-        if (self.line_info) |li| {
-            li.deinit(allocator);
-        }
-    }
-};
-const PdbOrDwarf = union(enum) {
-    pdb: pdb.Pdb,
-    dwarf: Dwarf,
-
-    fn deinit(self: *PdbOrDwarf, allocator: mem.Allocator) void {
-        switch (self.*) {
-            .pdb => |*inner| inner.deinit(),
-            .dwarf => |*inner| inner.deinit(allocator),
-        }
-    }
-};
-
 /// Allows the caller to freely write to stderr until `unlockStdErr` is called.
 ///
 /// During the lock, any `std.Progress` information is cleared from the terminal.
@@ -104,13 +82,13 @@ pub fn getStderrMutex() *std.Thread.Mutex {
 }
 
 /// TODO multithreaded awareness
-var self_debug_info: ?Info = null;
+var self_debug_info: ?SelfInfo = null;
 
-pub fn getSelfDebugInfo() !*Info {
+pub fn getSelfDebugInfo() !*SelfInfo {
     if (self_debug_info) |*info| {
         return info;
     } else {
-        self_debug_info = try openSelfDebugInfo(getDebugInfoAllocator());
+        self_debug_info = try SelfInfo.open(getDebugInfoAllocator());
         return &self_debug_info.?;
     }
 }
@@ -266,7 +244,7 @@ pub inline fn getContext(context: *ThreadContext) bool {
 /// Tries to print the stack trace starting from the supplied base pointer to stderr,
 /// unbuffered, and ignores any error returned.
 /// TODO multithreaded awareness
-pub fn dumpStackTraceFromBase(context: *const ThreadContext) void {
+pub fn dumpStackTraceFromBase(context: *ThreadContext) void {
     nosuspend {
         if (comptime builtin.target.isWasm()) {
             if (native_os == .wasi) {
@@ -348,7 +326,7 @@ pub fn captureStackTrace(first_address: ?usize, stack_trace: *std.builtin.StackT
         stack_trace.index = slice.len;
     } else {
         // TODO: This should use the DWARF unwinder if .eh_frame_hdr is available (so that full debug info parsing isn't required).
-        //       A new path for loading Info needs to be created which will only attempt to parse in-memory sections, because
+        //       A new path for loading SelfInfo needs to be created which will only attempt to parse in-memory sections, because
         //       stopping to load other debug info (ie. source line info) from disk here is not required for unwinding.
         var it = StackIterator.init(first_address, null);
         defer it.deinit();
@@ -526,7 +504,7 @@ pub fn writeStackTrace(
     stack_trace: std.builtin.StackTrace,
     out_stream: anytype,
     allocator: mem.Allocator,
-    debug_info: *Info,
+    debug_info: *SelfInfo,
     tty_config: io.tty.Config,
 ) !void {
     _ = allocator;
@@ -563,12 +541,12 @@ pub const StackIterator = struct {
     fp: usize,
     ma: MemoryAccessor = MemoryAccessor.init,
 
-    // When Info and a register context is available, this iterator can unwind
+    // When SelfInfo and a register context is available, this iterator can unwind
     // stacks with frames that don't use a frame pointer (ie. -fomit-frame-pointer),
     // using DWARF and MachO unwind info.
     unwind_state: if (have_ucontext) ?struct {
-        debug_info: *Info,
-        dwarf_context: Dwarf.UnwindContext,
+        debug_info: *SelfInfo,
+        dwarf_context: SelfInfo.UnwindContext,
         last_error: ?UnwindError = null,
         failed: bool = false,
     } else void = if (have_ucontext) null else {},
@@ -592,20 +570,22 @@ pub const StackIterator = struct {
         };
     }
 
-    pub fn initWithContext(first_address: ?usize, debug_info: *Info, context: *const posix.ucontext_t) !StackIterator {
+    pub fn initWithContext(first_address: ?usize, debug_info: *SelfInfo, context: *posix.ucontext_t) !StackIterator {
         // The implementation of DWARF unwinding on aarch64-macos is not complete. However, Apple mandates that
         // the frame pointer register is always used, so on this platform we can safely use the FP-based unwinder.
-        if (comptime builtin.target.isDarwin() and native_arch == .aarch64) {
+        if (builtin.target.isDarwin() and native_arch == .aarch64)
             return init(first_address, context.mcontext.ss.fp);
-        } else {
+
+        if (SelfInfo.supports_unwinding) {
             var iterator = init(first_address, null);
             iterator.unwind_state = .{
                 .debug_info = debug_info,
-                .dwarf_context = try Dwarf.UnwindContext.init(debug_info.allocator, context),
+                .dwarf_context = try SelfInfo.UnwindContext.init(debug_info.allocator, context),
             };
-
             return iterator;
         }
+
+        return init(first_address, null);
     }
 
     pub fn deinit(it: *StackIterator) void {
@@ -667,116 +647,6 @@ pub const StackIterator = struct {
         return address;
     }
 
-    fn isValidMemory(address: usize) bool {
-        // We are unable to determine validity of memory for freestanding targets
-        if (native_os == .freestanding or native_os == .uefi) return true;
-
-        const aligned_address = address & ~@as(usize, @intCast((mem.page_size - 1)));
-        if (aligned_address == 0) return false;
-        const aligned_memory = @as([*]align(mem.page_size) u8, @ptrFromInt(aligned_address))[0..mem.page_size];
-
-        if (native_os == .windows) {
-            var memory_info: windows.MEMORY_BASIC_INFORMATION = undefined;
-
-            // The only error this function can throw is ERROR_INVALID_PARAMETER.
-            // supply an address that invalid i'll be thrown.
-            const rc = windows.VirtualQuery(aligned_memory, &memory_info, aligned_memory.len) catch {
-                return false;
-            };
-
-            // Result code has to be bigger than zero (number of bytes written)
-            if (rc == 0) {
-                return false;
-            }
-
-            // Free pages cannot be read, they are unmapped
-            if (memory_info.State == windows.MEM_FREE) {
-                return false;
-            }
-
-            return true;
-        } else if (have_msync) {
-            posix.msync(aligned_memory, posix.MSF.ASYNC) catch |err| {
-                switch (err) {
-                    error.UnmappedMemory => return false,
-                    else => unreachable,
-                }
-            };
-
-            return true;
-        } else {
-            // We are unable to determine validity of memory on this target.
-            return true;
-        }
-    }
-
-    pub const MemoryAccessor = struct {
-        var cached_pid: posix.pid_t = -1;
-
-        mem: switch (native_os) {
-            .linux => File,
-            else => void,
-        },
-
-        pub const init: MemoryAccessor = .{
-            .mem = switch (native_os) {
-                .linux => .{ .handle = -1 },
-                else => {},
-            },
-        };
-
-        fn read(ma: *MemoryAccessor, address: usize, buf: []u8) bool {
-            switch (native_os) {
-                .linux => while (true) switch (ma.mem.handle) {
-                    -2 => break,
-                    -1 => {
-                        const linux = std.os.linux;
-                        const pid = switch (@atomicLoad(posix.pid_t, &cached_pid, .monotonic)) {
-                            -1 => pid: {
-                                const pid = linux.getpid();
-                                @atomicStore(posix.pid_t, &cached_pid, pid, .monotonic);
-                                break :pid pid;
-                            },
-                            else => |pid| pid,
-                        };
-                        const bytes_read = linux.process_vm_readv(
-                            pid,
-                            &.{.{ .base = buf.ptr, .len = buf.len }},
-                            &.{.{ .base = @ptrFromInt(address), .len = buf.len }},
-                            0,
-                        );
-                        switch (linux.E.init(bytes_read)) {
-                            .SUCCESS => return bytes_read == buf.len,
-                            .FAULT => return false,
-                            .INVAL, .PERM, .SRCH => unreachable, // own pid is always valid
-                            .NOMEM => {},
-                            .NOSYS => {}, // QEMU is known not to implement this syscall.
-                            else => unreachable, // unexpected
-                        }
-                        var path_buf: [
-                            std.fmt.count("/proc/{d}/mem", .{math.minInt(posix.pid_t)})
-                        ]u8 = undefined;
-                        const path = std.fmt.bufPrint(&path_buf, "/proc/{d}/mem", .{pid}) catch
-                            unreachable;
-                        ma.mem = std.fs.openFileAbsolute(path, .{}) catch {
-                            ma.mem.handle = -2;
-                            break;
-                        };
-                    },
-                    else => return (ma.mem.pread(buf, address) catch return false) == buf.len,
-                },
-                else => {},
-            }
-            if (!isValidMemory(address)) return false;
-            @memcpy(buf, @as([*]const u8, @ptrFromInt(address)));
-            return true;
-        }
-        pub fn load(ma: *MemoryAccessor, comptime Type: type, address: usize) ?Type {
-            var result: Type = undefined;
-            return if (ma.read(address, std.mem.asBytes(&result))) result else null;
-        }
-    };
-
     fn next_unwind(it: *StackIterator) !usize {
         const unwind_state = &it.unwind_state.?;
         const module = try unwind_state.debug_info.getModuleForAddress(unwind_state.dwarf_context.pc);
@@ -785,7 +655,13 @@ pub const StackIterator = struct {
                 // __unwind_info is a requirement for unwinding on Darwin. It may fall back to DWARF, but unwinding
                 // via DWARF before attempting to use the compact unwind info will produce incorrect results.
                 if (module.unwind_info) |unwind_info| {
-                    if (Dwarf.unwindFrameMachO(&unwind_state.dwarf_context, &it.ma, unwind_info, module.eh_frame, module.base_address)) |return_address| {
+                    if (SelfInfo.unwindFrameMachO(
+                        &unwind_state.dwarf_context,
+                        &it.ma,
+                        unwind_info,
+                        module.eh_frame,
+                        module.base_address,
+                    )) |return_address| {
                         return return_address;
                     } else |err| {
                         if (err != error.RequiresDWARFUnwind) return err;
@@ -796,7 +672,7 @@ pub const StackIterator = struct {
         }
 
         if (try module.getDwarfInfoForAddress(unwind_state.debug_info.allocator, unwind_state.dwarf_context.pc)) |di| {
-            return di.unwindFrame(&unwind_state.dwarf_context, &it.ma, null);
+            return SelfInfo.unwindFrameDwarf(di, &unwind_state.dwarf_context, &it.ma, null);
         } else return error.MissingDebugInfo;
     }
 
@@ -845,22 +721,19 @@ pub const StackIterator = struct {
     }
 };
 
-const have_msync = switch (native_os) {
-    .wasi, .emscripten, .windows => false,
-    else => true,
-};
-
 pub fn writeCurrentStackTrace(
     out_stream: anytype,
-    debug_info: *Info,
+    debug_info: *SelfInfo,
     tty_config: io.tty.Config,
     start_addr: ?usize,
 ) !void {
-    var context: ThreadContext = undefined;
-    const has_context = getContext(&context);
     if (native_os == .windows) {
+        var context: ThreadContext = undefined;
+        assert(getContext(&context));
         return writeStackTraceWindows(out_stream, debug_info, tty_config, &context, start_addr);
     }
+    var context: ThreadContext = undefined;
+    const has_context = getContext(&context);
 
     var it = (if (has_context) blk: {
         break :blk StackIterator.initWithContext(start_addr, debug_info, &context) catch null;
@@ -938,7 +811,7 @@ pub noinline fn walkStackWindows(addresses: []usize, existing_context: ?*const w
 
 pub fn writeStackTraceWindows(
     out_stream: anytype,
-    debug_info: *Info,
+    debug_info: *SelfInfo,
     tty_config: io.tty.Config,
     context: *const windows.CONTEXT,
     start_addr: ?usize,
@@ -957,52 +830,7 @@ pub fn writeStackTraceWindows(
     }
 }
 
-fn machoSearchSymbols(symbols: []const MachoSymbol, address: usize) ?*const MachoSymbol {
-    var min: usize = 0;
-    var max: usize = symbols.len - 1;
-    while (min < max) {
-        const mid = min + (max - min) / 2;
-        const curr = &symbols[mid];
-        const next = &symbols[mid + 1];
-        if (address >= next.address()) {
-            min = mid + 1;
-        } else if (address < curr.address()) {
-            max = mid;
-        } else {
-            return curr;
-        }
-    }
-
-    const max_sym = &symbols[symbols.len - 1];
-    if (address >= max_sym.address())
-        return max_sym;
-
-    return null;
-}
-
-test machoSearchSymbols {
-    const symbols = [_]MachoSymbol{
-        .{ .addr = 100, .strx = undefined, .size = undefined, .ofile = undefined },
-        .{ .addr = 200, .strx = undefined, .size = undefined, .ofile = undefined },
-        .{ .addr = 300, .strx = undefined, .size = undefined, .ofile = undefined },
-    };
-
-    try testing.expectEqual(null, machoSearchSymbols(&symbols, 0));
-    try testing.expectEqual(null, machoSearchSymbols(&symbols, 99));
-    try testing.expectEqual(&symbols[0], machoSearchSymbols(&symbols, 100).?);
-    try testing.expectEqual(&symbols[0], machoSearchSymbols(&symbols, 150).?);
-    try testing.expectEqual(&symbols[0], machoSearchSymbols(&symbols, 199).?);
-
-    try testing.expectEqual(&symbols[1], machoSearchSymbols(&symbols, 200).?);
-    try testing.expectEqual(&symbols[1], machoSearchSymbols(&symbols, 250).?);
-    try testing.expectEqual(&symbols[1], machoSearchSymbols(&symbols, 299).?);
-
-    try testing.expectEqual(&symbols[2], machoSearchSymbols(&symbols, 300).?);
-    try testing.expectEqual(&symbols[2], machoSearchSymbols(&symbols, 301).?);
-    try testing.expectEqual(&symbols[2], machoSearchSymbols(&symbols, 5000).?);
-}
-
-fn printUnknownSource(debug_info: *Info, out_stream: anytype, address: usize, tty_config: io.tty.Config) !void {
+fn printUnknownSource(debug_info: *SelfInfo, out_stream: anytype, address: usize, tty_config: io.tty.Config) !void {
     const module_name = debug_info.getModuleNameForAddress(address);
     return printLineInfo(
         out_stream,
@@ -1015,14 +843,14 @@ fn printUnknownSource(debug_info: *Info, out_stream: anytype, address: usize, tt
     );
 }
 
-fn printLastUnwindError(it: *StackIterator, debug_info: *Info, out_stream: anytype, tty_config: io.tty.Config) void {
+fn printLastUnwindError(it: *StackIterator, debug_info: *SelfInfo, out_stream: anytype, tty_config: io.tty.Config) void {
     if (!have_ucontext) return;
     if (it.getLastError()) |unwind_error| {
         printUnwindError(debug_info, out_stream, unwind_error.address, unwind_error.err, tty_config) catch {};
     }
 }
 
-fn printUnwindError(debug_info: *Info, out_stream: anytype, address: usize, err: UnwindError, tty_config: io.tty.Config) !void {
+fn printUnwindError(debug_info: *SelfInfo, out_stream: anytype, address: usize, err: UnwindError, tty_config: io.tty.Config) !void {
     const module_name = debug_info.getModuleNameForAddress(address) orelse "???";
     try tty_config.setColor(out_stream, .dim);
     if (err == error.MissingDebugInfo) {
@@ -1033,7 +861,7 @@ fn printUnwindError(debug_info: *Info, out_stream: anytype, address: usize, err:
     try tty_config.setColor(out_stream, .reset);
 }
 
-pub fn printSourceAtAddress(debug_info: *Info, out_stream: anytype, address: usize, tty_config: io.tty.Config) !void {
+pub fn printSourceAtAddress(debug_info: *SelfInfo, out_stream: anytype, address: usize, tty_config: io.tty.Config) !void {
     const module = debug_info.getModuleForAddress(address) catch |err| switch (err) {
         error.MissingDebugInfo, error.InvalidDebugInfo => return printUnknownSource(debug_info, out_stream, address, tty_config),
         else => return err,
@@ -1058,7 +886,7 @@ pub fn printSourceAtAddress(debug_info: *Info, out_stream: anytype, address: usi
 
 fn printLineInfo(
     out_stream: anytype,
-    line_info: ?LineInfo,
+    line_info: ?SourceLocation,
     address: usize,
     symbol_name: []const u8,
     compile_unit_name: []const u8,
@@ -1104,428 +932,7 @@ fn printLineInfo(
     }
 }
 
-pub const OpenSelfDebugInfoError = error{
-    MissingDebugInfo,
-    UnsupportedOperatingSystem,
-} || @typeInfo(@typeInfo(@TypeOf(Info.init)).Fn.return_type.?).ErrorUnion.error_set;
-
-pub fn openSelfDebugInfo(allocator: mem.Allocator) OpenSelfDebugInfoError!Info {
-    nosuspend {
-        if (builtin.strip_debug_info)
-            return error.MissingDebugInfo;
-        if (@hasDecl(root, "os") and @hasDecl(root.os, "debug") and @hasDecl(root.os.debug, "openSelfDebugInfo")) {
-            return root.os.debug.openSelfDebugInfo(allocator);
-        }
-        switch (native_os) {
-            .linux,
-            .freebsd,
-            .netbsd,
-            .dragonfly,
-            .openbsd,
-            .macos,
-            .solaris,
-            .illumos,
-            .windows,
-            => return try Info.init(allocator),
-            else => return error.UnsupportedOperatingSystem,
-        }
-    }
-}
-
-fn readCoffDebugInfo(allocator: mem.Allocator, coff_obj: *coff.Coff) !ModuleDebugInfo {
-    nosuspend {
-        var di = ModuleDebugInfo{
-            .base_address = undefined,
-            .coff_image_base = coff_obj.getImageBase(),
-            .coff_section_headers = undefined,
-        };
-
-        if (coff_obj.getSectionByName(".debug_info")) |_| {
-            // This coff file has embedded DWARF debug info
-            var sections: Dwarf.SectionArray = Dwarf.null_section_array;
-            errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
-
-            inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
-                sections[i] = if (coff_obj.getSectionByName("." ++ section.name)) |section_header| blk: {
-                    break :blk .{
-                        .data = try coff_obj.getSectionDataAlloc(section_header, allocator),
-                        .virtual_address = section_header.virtual_address,
-                        .owned = true,
-                    };
-                } else null;
-            }
-
-            var dwarf = Dwarf{
-                .endian = native_endian,
-                .sections = sections,
-                .is_macho = false,
-            };
-
-            try Dwarf.open(&dwarf, allocator);
-            di.dwarf = dwarf;
-        }
-
-        const raw_path = try coff_obj.getPdbPath() orelse return di;
-        const path = blk: {
-            if (fs.path.isAbsolute(raw_path)) {
-                break :blk raw_path;
-            } else {
-                const self_dir = try fs.selfExeDirPathAlloc(allocator);
-                defer allocator.free(self_dir);
-                break :blk try fs.path.join(allocator, &.{ self_dir, raw_path });
-            }
-        };
-        defer if (path.ptr != raw_path.ptr) allocator.free(path);
-
-        di.pdb = pdb.Pdb.init(allocator, path) catch |err| switch (err) {
-            error.FileNotFound, error.IsDir => {
-                if (di.dwarf == null) return error.MissingDebugInfo;
-                return di;
-            },
-            else => return err,
-        };
-        try di.pdb.?.parseInfoStream();
-        try di.pdb.?.parseDbiStream();
-
-        if (!mem.eql(u8, &coff_obj.guid, &di.pdb.?.guid) or coff_obj.age != di.pdb.?.age)
-            return error.InvalidDebugInfo;
-
-        // Only used by the pdb path
-        di.coff_section_headers = try coff_obj.getSectionHeadersAlloc(allocator);
-        errdefer allocator.free(di.coff_section_headers);
-
-        return di;
-    }
-}
-
-fn chopSlice(ptr: []const u8, offset: u64, size: u64) error{Overflow}![]const u8 {
-    const start = math.cast(usize, offset) orelse return error.Overflow;
-    const end = start + (math.cast(usize, size) orelse return error.Overflow);
-    return ptr[start..end];
-}
-
-/// Reads debug info from an ELF file, or the current binary if none in specified.
-/// If the required sections aren't present but a reference to external debug info is,
-/// then this this function will recurse to attempt to load the debug sections from
-/// an external file.
-pub fn readElfDebugInfo(
-    allocator: mem.Allocator,
-    elf_filename: ?[]const u8,
-    build_id: ?[]const u8,
-    expected_crc: ?u32,
-    parent_sections: *Dwarf.SectionArray,
-    parent_mapped_mem: ?[]align(mem.page_size) const u8,
-) !ModuleDebugInfo {
-    nosuspend {
-        const elf_file = (if (elf_filename) |filename| blk: {
-            break :blk fs.cwd().openFile(filename, .{});
-        } else fs.openSelfExe(.{})) catch |err| switch (err) {
-            error.FileNotFound => return error.MissingDebugInfo,
-            else => return err,
-        };
-
-        const mapped_mem = try mapWholeFile(elf_file);
-        if (expected_crc) |crc| if (crc != std.hash.crc.Crc32.hash(mapped_mem)) return error.InvalidDebugInfo;
-
-        const hdr: *const elf.Ehdr = @ptrCast(&mapped_mem[0]);
-        if (!mem.eql(u8, hdr.e_ident[0..4], elf.MAGIC)) return error.InvalidElfMagic;
-        if (hdr.e_ident[elf.EI_VERSION] != 1) return error.InvalidElfVersion;
-
-        const endian: std.builtin.Endian = switch (hdr.e_ident[elf.EI_DATA]) {
-            elf.ELFDATA2LSB => .little,
-            elf.ELFDATA2MSB => .big,
-            else => return error.InvalidElfEndian,
-        };
-        assert(endian == native_endian); // this is our own debug info
-
-        const shoff = hdr.e_shoff;
-        const str_section_off = shoff + @as(u64, hdr.e_shentsize) * @as(u64, hdr.e_shstrndx);
-        const str_shdr: *const elf.Shdr = @ptrCast(@alignCast(&mapped_mem[math.cast(usize, str_section_off) orelse return error.Overflow]));
-        const header_strings = mapped_mem[str_shdr.sh_offset..][0..str_shdr.sh_size];
-        const shdrs = @as(
-            [*]const elf.Shdr,
-            @ptrCast(@alignCast(&mapped_mem[shoff])),
-        )[0..hdr.e_shnum];
-
-        var sections: Dwarf.SectionArray = Dwarf.null_section_array;
-
-        // Combine section list. This takes ownership over any owned sections from the parent scope.
-        for (parent_sections, &sections) |*parent, *section| {
-            if (parent.*) |*p| {
-                section.* = p.*;
-                p.owned = false;
-            }
-        }
-        errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
-
-        var separate_debug_filename: ?[]const u8 = null;
-        var separate_debug_crc: ?u32 = null;
-
-        for (shdrs) |*shdr| {
-            if (shdr.sh_type == elf.SHT_NULL or shdr.sh_type == elf.SHT_NOBITS) continue;
-            const name = mem.sliceTo(header_strings[shdr.sh_name..], 0);
-
-            if (mem.eql(u8, name, ".gnu_debuglink")) {
-                const gnu_debuglink = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
-                const debug_filename = mem.sliceTo(@as([*:0]const u8, @ptrCast(gnu_debuglink.ptr)), 0);
-                const crc_offset = mem.alignForward(usize, @intFromPtr(&debug_filename[debug_filename.len]) + 1, 4) - @intFromPtr(gnu_debuglink.ptr);
-                const crc_bytes = gnu_debuglink[crc_offset..][0..4];
-                separate_debug_crc = mem.readInt(u32, crc_bytes, native_endian);
-                separate_debug_filename = debug_filename;
-                continue;
-            }
-
-            var section_index: ?usize = null;
-            inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
-                if (mem.eql(u8, "." ++ section.name, name)) section_index = i;
-            }
-            if (section_index == null) continue;
-            if (sections[section_index.?] != null) continue;
-
-            const section_bytes = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
-            sections[section_index.?] = if ((shdr.sh_flags & elf.SHF_COMPRESSED) > 0) blk: {
-                var section_stream = io.fixedBufferStream(section_bytes);
-                var section_reader = section_stream.reader();
-                const chdr = section_reader.readStruct(elf.Chdr) catch continue;
-                if (chdr.ch_type != .ZLIB) continue;
-
-                var zlib_stream = std.compress.zlib.decompressor(section_stream.reader());
-
-                const decompressed_section = try allocator.alloc(u8, chdr.ch_size);
-                errdefer allocator.free(decompressed_section);
-
-                const read = zlib_stream.reader().readAll(decompressed_section) catch continue;
-                assert(read == decompressed_section.len);
-
-                break :blk .{
-                    .data = decompressed_section,
-                    .virtual_address = shdr.sh_addr,
-                    .owned = true,
-                };
-            } else .{
-                .data = section_bytes,
-                .virtual_address = shdr.sh_addr,
-                .owned = false,
-            };
-        }
-
-        const missing_debug_info =
-            sections[@intFromEnum(Dwarf.Section.Id.debug_info)] == null or
-            sections[@intFromEnum(Dwarf.Section.Id.debug_abbrev)] == null or
-            sections[@intFromEnum(Dwarf.Section.Id.debug_str)] == null or
-            sections[@intFromEnum(Dwarf.Section.Id.debug_line)] == null;
-
-        // Attempt to load debug info from an external file
-        // See: https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
-        if (missing_debug_info) {
-
-            // Only allow one level of debug info nesting
-            if (parent_mapped_mem) |_| {
-                return error.MissingDebugInfo;
-            }
-
-            const global_debug_directories = [_][]const u8{
-                "/usr/lib/debug",
-            };
-
-            // <global debug directory>/.build-id/<2-character id prefix>/<id remainder>.debug
-            if (build_id) |id| blk: {
-                if (id.len < 3) break :blk;
-
-                // Either md5 (16 bytes) or sha1 (20 bytes) are used here in practice
-                const extension = ".debug";
-                var id_prefix_buf: [2]u8 = undefined;
-                var filename_buf: [38 + extension.len]u8 = undefined;
-
-                _ = std.fmt.bufPrint(&id_prefix_buf, "{s}", .{std.fmt.fmtSliceHexLower(id[0..1])}) catch unreachable;
-                const filename = std.fmt.bufPrint(
-                    &filename_buf,
-                    "{s}" ++ extension,
-                    .{std.fmt.fmtSliceHexLower(id[1..])},
-                ) catch break :blk;
-
-                for (global_debug_directories) |global_directory| {
-                    const path = try fs.path.join(allocator, &.{ global_directory, ".build-id", &id_prefix_buf, filename });
-                    defer allocator.free(path);
-
-                    return readElfDebugInfo(allocator, path, null, separate_debug_crc, &sections, mapped_mem) catch continue;
-                }
-            }
-
-            // use the path from .gnu_debuglink, in the same search order as gdb
-            if (separate_debug_filename) |separate_filename| blk: {
-                if (elf_filename != null and mem.eql(u8, elf_filename.?, separate_filename)) return error.MissingDebugInfo;
-
-                // <cwd>/<gnu_debuglink>
-                if (readElfDebugInfo(allocator, separate_filename, null, separate_debug_crc, &sections, mapped_mem)) |debug_info| return debug_info else |_| {}
-
-                // <cwd>/.debug/<gnu_debuglink>
-                {
-                    const path = try fs.path.join(allocator, &.{ ".debug", separate_filename });
-                    defer allocator.free(path);
-
-                    if (readElfDebugInfo(allocator, path, null, separate_debug_crc, &sections, mapped_mem)) |debug_info| return debug_info else |_| {}
-                }
-
-                var cwd_buf: [fs.max_path_bytes]u8 = undefined;
-                const cwd_path = posix.realpath(".", &cwd_buf) catch break :blk;
-
-                // <global debug directory>/<absolute folder of current binary>/<gnu_debuglink>
-                for (global_debug_directories) |global_directory| {
-                    const path = try fs.path.join(allocator, &.{ global_directory, cwd_path, separate_filename });
-                    defer allocator.free(path);
-                    if (readElfDebugInfo(allocator, path, null, separate_debug_crc, &sections, mapped_mem)) |debug_info| return debug_info else |_| {}
-                }
-            }
-
-            return error.MissingDebugInfo;
-        }
-
-        var di = Dwarf{
-            .endian = endian,
-            .sections = sections,
-            .is_macho = false,
-        };
-
-        try Dwarf.open(&di, allocator);
-
-        return ModuleDebugInfo{
-            .base_address = undefined,
-            .dwarf = di,
-            .mapped_memory = parent_mapped_mem orelse mapped_mem,
-            .external_mapped_memory = if (parent_mapped_mem != null) mapped_mem else null,
-        };
-    }
-}
-
-/// This takes ownership of macho_file: users of this function should not close
-/// it themselves, even on error.
-/// TODO it's weird to take ownership even on error, rework this code.
-fn readMachODebugInfo(allocator: mem.Allocator, macho_file: File) !ModuleDebugInfo {
-    const mapped_mem = try mapWholeFile(macho_file);
-
-    const hdr: *const macho.mach_header_64 = @ptrCast(@alignCast(mapped_mem.ptr));
-    if (hdr.magic != macho.MH_MAGIC_64)
-        return error.InvalidDebugInfo;
-
-    var it = macho.LoadCommandIterator{
-        .ncmds = hdr.ncmds,
-        .buffer = mapped_mem[@sizeOf(macho.mach_header_64)..][0..hdr.sizeofcmds],
-    };
-    const symtab = while (it.next()) |cmd| switch (cmd.cmd()) {
-        .SYMTAB => break cmd.cast(macho.symtab_command).?,
-        else => {},
-    } else return error.MissingDebugInfo;
-
-    const syms = @as(
-        [*]const macho.nlist_64,
-        @ptrCast(@alignCast(&mapped_mem[symtab.symoff])),
-    )[0..symtab.nsyms];
-    const strings = mapped_mem[symtab.stroff..][0 .. symtab.strsize - 1 :0];
-
-    const symbols_buf = try allocator.alloc(MachoSymbol, syms.len);
-
-    var ofile: u32 = undefined;
-    var last_sym: MachoSymbol = undefined;
-    var symbol_index: usize = 0;
-    var state: enum {
-        init,
-        oso_open,
-        oso_close,
-        bnsym,
-        fun_strx,
-        fun_size,
-        ensym,
-    } = .init;
-
-    for (syms) |*sym| {
-        if (!sym.stab()) continue;
-
-        // TODO handle globals N_GSYM, and statics N_STSYM
-        switch (sym.n_type) {
-            macho.N_OSO => {
-                switch (state) {
-                    .init, .oso_close => {
-                        state = .oso_open;
-                        ofile = sym.n_strx;
-                    },
-                    else => return error.InvalidDebugInfo,
-                }
-            },
-            macho.N_BNSYM => {
-                switch (state) {
-                    .oso_open, .ensym => {
-                        state = .bnsym;
-                        last_sym = .{
-                            .strx = 0,
-                            .addr = sym.n_value,
-                            .size = 0,
-                            .ofile = ofile,
-                        };
-                    },
-                    else => return error.InvalidDebugInfo,
-                }
-            },
-            macho.N_FUN => {
-                switch (state) {
-                    .bnsym => {
-                        state = .fun_strx;
-                        last_sym.strx = sym.n_strx;
-                    },
-                    .fun_strx => {
-                        state = .fun_size;
-                        last_sym.size = @as(u32, @intCast(sym.n_value));
-                    },
-                    else => return error.InvalidDebugInfo,
-                }
-            },
-            macho.N_ENSYM => {
-                switch (state) {
-                    .fun_size => {
-                        state = .ensym;
-                        symbols_buf[symbol_index] = last_sym;
-                        symbol_index += 1;
-                    },
-                    else => return error.InvalidDebugInfo,
-                }
-            },
-            macho.N_SO => {
-                switch (state) {
-                    .init, .oso_close => {},
-                    .oso_open, .ensym => {
-                        state = .oso_close;
-                    },
-                    else => return error.InvalidDebugInfo,
-                }
-            },
-            else => {},
-        }
-    }
-
-    switch (state) {
-        .init => return error.MissingDebugInfo,
-        .oso_close => {},
-        else => return error.InvalidDebugInfo,
-    }
-
-    const symbols = try allocator.realloc(symbols_buf, symbol_index);
-
-    // Even though lld emits symbols in ascending order, this debug code
-    // should work for programs linked in any valid way.
-    // This sort is so that we can binary search later.
-    mem.sort(MachoSymbol, symbols, {}, MachoSymbol.addressLessThan);
-
-    return ModuleDebugInfo{
-        .base_address = undefined,
-        .vmaddr_slide = undefined,
-        .mapped_memory = mapped_mem,
-        .ofiles = ModuleDebugInfo.OFileTable.init(allocator),
-        .symbols = symbols,
-        .strings = strings,
-    };
-}
-
-fn printLineFromFileAnyOs(out_stream: anytype, line_info: LineInfo) !void {
+fn printLineFromFileAnyOs(out_stream: anytype, line_info: SourceLocation) !void {
     // Need this to always block even in async I/O mode, because this could potentially
     // be called from e.g. the event loop code crashing.
     var f = try fs.cwd().openFile(line_info.file_name, .{});
@@ -1591,7 +998,7 @@ test printLineFromFileAnyOs {
 
     var test_dir = std.testing.tmpDir(.{});
     defer test_dir.cleanup();
-    // Relies on testing.tmpDir internals which is not ideal, but LineInfo requires paths.
+    // Relies on testing.tmpDir internals which is not ideal, but SourceLocation requires paths.
     const test_dir_path = try join(allocator, &.{ ".zig-cache", "tmp", test_dir.sub_path[0..] });
     defer allocator.free(test_dir_path);
 
@@ -1702,871 +1109,6 @@ test printLineFromFileAnyOs {
     }
 }
 
-const MachoSymbol = struct {
-    strx: u32,
-    addr: u64,
-    size: u32,
-    ofile: u32,
-
-    /// Returns the address from the macho file
-    fn address(self: MachoSymbol) u64 {
-        return self.addr;
-    }
-
-    fn addressLessThan(context: void, lhs: MachoSymbol, rhs: MachoSymbol) bool {
-        _ = context;
-        return lhs.addr < rhs.addr;
-    }
-};
-
-/// Takes ownership of file, even on error.
-/// TODO it's weird to take ownership even on error, rework this code.
-fn mapWholeFile(file: File) ![]align(mem.page_size) const u8 {
-    nosuspend {
-        defer file.close();
-
-        const file_len = math.cast(usize, try file.getEndPos()) orelse math.maxInt(usize);
-        const mapped_mem = try posix.mmap(
-            null,
-            file_len,
-            posix.PROT.READ,
-            .{ .TYPE = .SHARED },
-            file.handle,
-            0,
-        );
-        errdefer posix.munmap(mapped_mem);
-
-        return mapped_mem;
-    }
-}
-
-pub const WindowsModuleInfo = struct {
-    base_address: usize,
-    size: u32,
-    name: []const u8,
-    handle: windows.HMODULE,
-
-    // Set when the image file needed to be mapped from disk
-    mapped_file: ?struct {
-        file: File,
-        section_handle: windows.HANDLE,
-        section_view: []const u8,
-
-        pub fn deinit(self: @This()) void {
-            const process_handle = windows.GetCurrentProcess();
-            assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @constCast(@ptrCast(self.section_view.ptr))) == .SUCCESS);
-            windows.CloseHandle(self.section_handle);
-            self.file.close();
-        }
-    } = null,
-};
-
-pub const Info = struct {
-    allocator: mem.Allocator,
-    address_map: std.AutoHashMap(usize, *ModuleDebugInfo),
-    modules: if (native_os == .windows) std.ArrayListUnmanaged(WindowsModuleInfo) else void,
-
-    pub fn init(allocator: mem.Allocator) !Info {
-        var debug_info = Info{
-            .allocator = allocator,
-            .address_map = std.AutoHashMap(usize, *ModuleDebugInfo).init(allocator),
-            .modules = if (native_os == .windows) .{} else {},
-        };
-
-        if (native_os == .windows) {
-            errdefer debug_info.modules.deinit(allocator);
-
-            const handle = windows.kernel32.CreateToolhelp32Snapshot(windows.TH32CS_SNAPMODULE | windows.TH32CS_SNAPMODULE32, 0);
-            if (handle == windows.INVALID_HANDLE_VALUE) {
-                switch (windows.GetLastError()) {
-                    else => |err| return windows.unexpectedError(err),
-                }
-            }
-            defer windows.CloseHandle(handle);
-
-            var module_entry: windows.MODULEENTRY32 = undefined;
-            module_entry.dwSize = @sizeOf(windows.MODULEENTRY32);
-            if (windows.kernel32.Module32First(handle, &module_entry) == 0) {
-                return error.MissingDebugInfo;
-            }
-
-            var module_valid = true;
-            while (module_valid) {
-                const module_info = try debug_info.modules.addOne(allocator);
-                const name = allocator.dupe(u8, mem.sliceTo(&module_entry.szModule, 0)) catch &.{};
-                errdefer allocator.free(name);
-
-                module_info.* = .{
-                    .base_address = @intFromPtr(module_entry.modBaseAddr),
-                    .size = module_entry.modBaseSize,
-                    .name = name,
-                    .handle = module_entry.hModule,
-                };
-
-                module_valid = windows.kernel32.Module32Next(handle, &module_entry) == 1;
-            }
-        }
-
-        return debug_info;
-    }
-
-    pub fn deinit(self: *Info) void {
-        var it = self.address_map.iterator();
-        while (it.next()) |entry| {
-            const mdi = entry.value_ptr.*;
-            mdi.deinit(self.allocator);
-            self.allocator.destroy(mdi);
-        }
-        self.address_map.deinit();
-        if (native_os == .windows) {
-            for (self.modules.items) |module| {
-                self.allocator.free(module.name);
-                if (module.mapped_file) |mapped_file| mapped_file.deinit();
-            }
-            self.modules.deinit(self.allocator);
-        }
-    }
-
-    pub fn getModuleForAddress(self: *Info, address: usize) !*ModuleDebugInfo {
-        if (comptime builtin.target.isDarwin()) {
-            return self.lookupModuleDyld(address);
-        } else if (native_os == .windows) {
-            return self.lookupModuleWin32(address);
-        } else if (native_os == .haiku) {
-            return self.lookupModuleHaiku(address);
-        } else if (comptime builtin.target.isWasm()) {
-            return self.lookupModuleWasm(address);
-        } else {
-            return self.lookupModuleDl(address);
-        }
-    }
-
-    // Returns the module name for a given address.
-    // This can be called when getModuleForAddress fails, so implementations should provide
-    // a path that doesn't rely on any side-effects of a prior successful module lookup.
-    pub fn getModuleNameForAddress(self: *Info, address: usize) ?[]const u8 {
-        if (comptime builtin.target.isDarwin()) {
-            return self.lookupModuleNameDyld(address);
-        } else if (native_os == .windows) {
-            return self.lookupModuleNameWin32(address);
-        } else if (native_os == .haiku) {
-            return null;
-        } else if (comptime builtin.target.isWasm()) {
-            return null;
-        } else {
-            return self.lookupModuleNameDl(address);
-        }
-    }
-
-    fn lookupModuleDyld(self: *Info, address: usize) !*ModuleDebugInfo {
-        const image_count = std.c._dyld_image_count();
-
-        var i: u32 = 0;
-        while (i < image_count) : (i += 1) {
-            const header = std.c._dyld_get_image_header(i) orelse continue;
-            const base_address = @intFromPtr(header);
-            if (address < base_address) continue;
-            const vmaddr_slide = std.c._dyld_get_image_vmaddr_slide(i);
-
-            var it = macho.LoadCommandIterator{
-                .ncmds = header.ncmds,
-                .buffer = @alignCast(@as(
-                    [*]u8,
-                    @ptrFromInt(@intFromPtr(header) + @sizeOf(macho.mach_header_64)),
-                )[0..header.sizeofcmds]),
-            };
-
-            var unwind_info: ?[]const u8 = null;
-            var eh_frame: ?[]const u8 = null;
-            while (it.next()) |cmd| switch (cmd.cmd()) {
-                .SEGMENT_64 => {
-                    const segment_cmd = cmd.cast(macho.segment_command_64).?;
-                    if (!mem.eql(u8, "__TEXT", segment_cmd.segName())) continue;
-
-                    const seg_start = segment_cmd.vmaddr + vmaddr_slide;
-                    const seg_end = seg_start + segment_cmd.vmsize;
-                    if (address >= seg_start and address < seg_end) {
-                        if (self.address_map.get(base_address)) |obj_di| {
-                            return obj_di;
-                        }
-
-                        for (cmd.getSections()) |sect| {
-                            if (mem.eql(u8, "__unwind_info", sect.sectName())) {
-                                unwind_info = @as([*]const u8, @ptrFromInt(sect.addr + vmaddr_slide))[0..sect.size];
-                            } else if (mem.eql(u8, "__eh_frame", sect.sectName())) {
-                                eh_frame = @as([*]const u8, @ptrFromInt(sect.addr + vmaddr_slide))[0..sect.size];
-                            }
-                        }
-
-                        const obj_di = try self.allocator.create(ModuleDebugInfo);
-                        errdefer self.allocator.destroy(obj_di);
-
-                        const macho_path = mem.sliceTo(std.c._dyld_get_image_name(i), 0);
-                        const macho_file = fs.cwd().openFile(macho_path, .{}) catch |err| switch (err) {
-                            error.FileNotFound => return error.MissingDebugInfo,
-                            else => return err,
-                        };
-                        obj_di.* = try readMachODebugInfo(self.allocator, macho_file);
-                        obj_di.base_address = base_address;
-                        obj_di.vmaddr_slide = vmaddr_slide;
-                        obj_di.unwind_info = unwind_info;
-                        obj_di.eh_frame = eh_frame;
-
-                        try self.address_map.putNoClobber(base_address, obj_di);
-
-                        return obj_di;
-                    }
-                },
-                else => {},
-            };
-        }
-
-        return error.MissingDebugInfo;
-    }
-
-    fn lookupModuleNameDyld(self: *Info, address: usize) ?[]const u8 {
-        _ = self;
-        const image_count = std.c._dyld_image_count();
-
-        var i: u32 = 0;
-        while (i < image_count) : (i += 1) {
-            const header = std.c._dyld_get_image_header(i) orelse continue;
-            const base_address = @intFromPtr(header);
-            if (address < base_address) continue;
-            const vmaddr_slide = std.c._dyld_get_image_vmaddr_slide(i);
-
-            var it = macho.LoadCommandIterator{
-                .ncmds = header.ncmds,
-                .buffer = @alignCast(@as(
-                    [*]u8,
-                    @ptrFromInt(@intFromPtr(header) + @sizeOf(macho.mach_header_64)),
-                )[0..header.sizeofcmds]),
-            };
-
-            while (it.next()) |cmd| switch (cmd.cmd()) {
-                .SEGMENT_64 => {
-                    const segment_cmd = cmd.cast(macho.segment_command_64).?;
-                    if (!mem.eql(u8, "__TEXT", segment_cmd.segName())) continue;
-
-                    const original_address = address - vmaddr_slide;
-                    const seg_start = segment_cmd.vmaddr;
-                    const seg_end = seg_start + segment_cmd.vmsize;
-                    if (original_address >= seg_start and original_address < seg_end) {
-                        return fs.path.basename(mem.sliceTo(std.c._dyld_get_image_name(i), 0));
-                    }
-                },
-                else => {},
-            };
-        }
-
-        return null;
-    }
-
-    fn lookupModuleWin32(self: *Info, address: usize) !*ModuleDebugInfo {
-        for (self.modules.items) |*module| {
-            if (address >= module.base_address and address < module.base_address + module.size) {
-                if (self.address_map.get(module.base_address)) |obj_di| {
-                    return obj_di;
-                }
-
-                const obj_di = try self.allocator.create(ModuleDebugInfo);
-                errdefer self.allocator.destroy(obj_di);
-
-                const mapped_module = @as([*]const u8, @ptrFromInt(module.base_address))[0..module.size];
-                var coff_obj = try coff.Coff.init(mapped_module, true);
-
-                // The string table is not mapped into memory by the loader, so if a section name is in the
-                // string table then we have to map the full image file from disk. This can happen when
-                // a binary is produced with -gdwarf, since the section names are longer than 8 bytes.
-                if (coff_obj.strtabRequired()) {
-                    var name_buffer: [windows.PATH_MAX_WIDE + 4:0]u16 = undefined;
-                    // openFileAbsoluteW requires the prefix to be present
-                    @memcpy(name_buffer[0..4], &[_]u16{ '\\', '?', '?', '\\' });
-
-                    const process_handle = windows.GetCurrentProcess();
-                    const len = windows.kernel32.GetModuleFileNameExW(
-                        process_handle,
-                        module.handle,
-                        @ptrCast(&name_buffer[4]),
-                        windows.PATH_MAX_WIDE,
-                    );
-
-                    if (len == 0) return error.MissingDebugInfo;
-                    const coff_file = fs.openFileAbsoluteW(name_buffer[0 .. len + 4 :0], .{}) catch |err| switch (err) {
-                        error.FileNotFound => return error.MissingDebugInfo,
-                        else => return err,
-                    };
-                    errdefer coff_file.close();
-
-                    var section_handle: windows.HANDLE = undefined;
-                    const create_section_rc = windows.ntdll.NtCreateSection(
-                        &section_handle,
-                        windows.STANDARD_RIGHTS_REQUIRED | windows.SECTION_QUERY | windows.SECTION_MAP_READ,
-                        null,
-                        null,
-                        windows.PAGE_READONLY,
-                        // The documentation states that if no AllocationAttribute is specified, then SEC_COMMIT is the default.
-                        // In practice, this isn't the case and specifying 0 will result in INVALID_PARAMETER_6.
-                        windows.SEC_COMMIT,
-                        coff_file.handle,
-                    );
-                    if (create_section_rc != .SUCCESS) return error.MissingDebugInfo;
-                    errdefer windows.CloseHandle(section_handle);
-
-                    var coff_len: usize = 0;
-                    var base_ptr: usize = 0;
-                    const map_section_rc = windows.ntdll.NtMapViewOfSection(
-                        section_handle,
-                        process_handle,
-                        @ptrCast(&base_ptr),
-                        null,
-                        0,
-                        null,
-                        &coff_len,
-                        .ViewUnmap,
-                        0,
-                        windows.PAGE_READONLY,
-                    );
-                    if (map_section_rc != .SUCCESS) return error.MissingDebugInfo;
-                    errdefer assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @ptrFromInt(base_ptr)) == .SUCCESS);
-
-                    const section_view = @as([*]const u8, @ptrFromInt(base_ptr))[0..coff_len];
-                    coff_obj = try coff.Coff.init(section_view, false);
-
-                    module.mapped_file = .{
-                        .file = coff_file,
-                        .section_handle = section_handle,
-                        .section_view = section_view,
-                    };
-                }
-                errdefer if (module.mapped_file) |mapped_file| mapped_file.deinit();
-
-                obj_di.* = try readCoffDebugInfo(self.allocator, &coff_obj);
-                obj_di.base_address = module.base_address;
-
-                try self.address_map.putNoClobber(module.base_address, obj_di);
-                return obj_di;
-            }
-        }
-
-        return error.MissingDebugInfo;
-    }
-
-    fn lookupModuleNameWin32(self: *Info, address: usize) ?[]const u8 {
-        for (self.modules.items) |module| {
-            if (address >= module.base_address and address < module.base_address + module.size) {
-                return module.name;
-            }
-        }
-        return null;
-    }
-
-    fn lookupModuleNameDl(self: *Info, address: usize) ?[]const u8 {
-        _ = self;
-
-        var ctx: struct {
-            // Input
-            address: usize,
-            // Output
-            name: []const u8 = "",
-        } = .{ .address = address };
-        const CtxTy = @TypeOf(ctx);
-
-        if (posix.dl_iterate_phdr(&ctx, error{Found}, struct {
-            fn callback(info: *posix.dl_phdr_info, size: usize, context: *CtxTy) !void {
-                _ = size;
-                if (context.address < info.addr) return;
-                const phdrs = info.phdr[0..info.phnum];
-                for (phdrs) |*phdr| {
-                    if (phdr.p_type != elf.PT_LOAD) continue;
-
-                    const seg_start = info.addr +% phdr.p_vaddr;
-                    const seg_end = seg_start + phdr.p_memsz;
-                    if (context.address >= seg_start and context.address < seg_end) {
-                        context.name = mem.sliceTo(info.name, 0) orelse "";
-                        break;
-                    }
-                } else return;
-
-                return error.Found;
-            }
-        }.callback)) {
-            return null;
-        } else |err| switch (err) {
-            error.Found => return fs.path.basename(ctx.name),
-        }
-
-        return null;
-    }
-
-    fn lookupModuleDl(self: *Info, address: usize) !*ModuleDebugInfo {
-        var ctx: struct {
-            // Input
-            address: usize,
-            // Output
-            base_address: usize = undefined,
-            name: []const u8 = undefined,
-            build_id: ?[]const u8 = null,
-            gnu_eh_frame: ?[]const u8 = null,
-        } = .{ .address = address };
-        const CtxTy = @TypeOf(ctx);
-
-        if (posix.dl_iterate_phdr(&ctx, error{Found}, struct {
-            fn callback(info: *posix.dl_phdr_info, size: usize, context: *CtxTy) !void {
-                _ = size;
-                // The base address is too high
-                if (context.address < info.addr)
-                    return;
-
-                const phdrs = info.phdr[0..info.phnum];
-                for (phdrs) |*phdr| {
-                    if (phdr.p_type != elf.PT_LOAD) continue;
-
-                    // Overflowing addition is used to handle the case of VSDOs having a p_vaddr = 0xffffffffff700000
-                    const seg_start = info.addr +% phdr.p_vaddr;
-                    const seg_end = seg_start + phdr.p_memsz;
-                    if (context.address >= seg_start and context.address < seg_end) {
-                        // Android libc uses NULL instead of an empty string to mark the
-                        // main program
-                        context.name = mem.sliceTo(info.name, 0) orelse "";
-                        context.base_address = info.addr;
-                        break;
-                    }
-                } else return;
-
-                for (info.phdr[0..info.phnum]) |phdr| {
-                    switch (phdr.p_type) {
-                        elf.PT_NOTE => {
-                            // Look for .note.gnu.build-id
-                            const note_bytes = @as([*]const u8, @ptrFromInt(info.addr + phdr.p_vaddr))[0..phdr.p_memsz];
-                            const name_size = mem.readInt(u32, note_bytes[0..4], native_endian);
-                            if (name_size != 4) continue;
-                            const desc_size = mem.readInt(u32, note_bytes[4..8], native_endian);
-                            const note_type = mem.readInt(u32, note_bytes[8..12], native_endian);
-                            if (note_type != elf.NT_GNU_BUILD_ID) continue;
-                            if (!mem.eql(u8, "GNU\x00", note_bytes[12..16])) continue;
-                            context.build_id = note_bytes[16..][0..desc_size];
-                        },
-                        elf.PT_GNU_EH_FRAME => {
-                            context.gnu_eh_frame = @as([*]const u8, @ptrFromInt(info.addr + phdr.p_vaddr))[0..phdr.p_memsz];
-                        },
-                        else => {},
-                    }
-                }
-
-                // Stop the iteration
-                return error.Found;
-            }
-        }.callback)) {
-            return error.MissingDebugInfo;
-        } else |err| switch (err) {
-            error.Found => {},
-        }
-
-        if (self.address_map.get(ctx.base_address)) |obj_di| {
-            return obj_di;
-        }
-
-        const obj_di = try self.allocator.create(ModuleDebugInfo);
-        errdefer self.allocator.destroy(obj_di);
-
-        var sections: Dwarf.SectionArray = Dwarf.null_section_array;
-        if (ctx.gnu_eh_frame) |eh_frame_hdr| {
-            // This is a special case - pointer offsets inside .eh_frame_hdr
-            // are encoded relative to its base address, so we must use the
-            // version that is already memory mapped, and not the one that
-            // will be mapped separately from the ELF file.
-            sections[@intFromEnum(Dwarf.Section.Id.eh_frame_hdr)] = .{
-                .data = eh_frame_hdr,
-                .owned = false,
-            };
-        }
-
-        obj_di.* = try readElfDebugInfo(self.allocator, if (ctx.name.len > 0) ctx.name else null, ctx.build_id, null, &sections, null);
-        obj_di.base_address = ctx.base_address;
-
-        // Missing unwind info isn't treated as a failure, as the unwinder will fall back to FP-based unwinding
-        obj_di.dwarf.scanAllUnwindInfo(self.allocator, ctx.base_address) catch {};
-
-        try self.address_map.putNoClobber(ctx.base_address, obj_di);
-
-        return obj_di;
-    }
-
-    fn lookupModuleHaiku(self: *Info, address: usize) !*ModuleDebugInfo {
-        _ = self;
-        _ = address;
-        @panic("TODO implement lookup module for Haiku");
-    }
-
-    fn lookupModuleWasm(self: *Info, address: usize) !*ModuleDebugInfo {
-        _ = self;
-        _ = address;
-        @panic("TODO implement lookup module for Wasm");
-    }
-};
-
-pub const ModuleDebugInfo = switch (native_os) {
-    .macos, .ios, .watchos, .tvos, .visionos => struct {
-        base_address: usize,
-        vmaddr_slide: usize,
-        mapped_memory: []align(mem.page_size) const u8,
-        symbols: []const MachoSymbol,
-        strings: [:0]const u8,
-        ofiles: OFileTable,
-
-        // Backed by the in-memory sections mapped by the loader
-        unwind_info: ?[]const u8 = null,
-        eh_frame: ?[]const u8 = null,
-
-        const OFileTable = std.StringHashMap(OFileInfo);
-        const OFileInfo = struct {
-            di: Dwarf,
-            addr_table: std.StringHashMap(u64),
-        };
-
-        pub fn deinit(self: *@This(), allocator: mem.Allocator) void {
-            var it = self.ofiles.iterator();
-            while (it.next()) |entry| {
-                const ofile = entry.value_ptr;
-                ofile.di.deinit(allocator);
-                ofile.addr_table.deinit();
-            }
-            self.ofiles.deinit();
-            allocator.free(self.symbols);
-            posix.munmap(self.mapped_memory);
-        }
-
-        fn loadOFile(self: *@This(), allocator: mem.Allocator, o_file_path: []const u8) !*OFileInfo {
-            const o_file = try fs.cwd().openFile(o_file_path, .{});
-            const mapped_mem = try mapWholeFile(o_file);
-
-            const hdr: *const macho.mach_header_64 = @ptrCast(@alignCast(mapped_mem.ptr));
-            if (hdr.magic != std.macho.MH_MAGIC_64)
-                return error.InvalidDebugInfo;
-
-            var segcmd: ?macho.LoadCommandIterator.LoadCommand = null;
-            var symtabcmd: ?macho.symtab_command = null;
-            var it = macho.LoadCommandIterator{
-                .ncmds = hdr.ncmds,
-                .buffer = mapped_mem[@sizeOf(macho.mach_header_64)..][0..hdr.sizeofcmds],
-            };
-            while (it.next()) |cmd| switch (cmd.cmd()) {
-                .SEGMENT_64 => segcmd = cmd,
-                .SYMTAB => symtabcmd = cmd.cast(macho.symtab_command).?,
-                else => {},
-            };
-
-            if (segcmd == null or symtabcmd == null) return error.MissingDebugInfo;
-
-            // Parse symbols
-            const strtab = @as(
-                [*]const u8,
-                @ptrCast(&mapped_mem[symtabcmd.?.stroff]),
-            )[0 .. symtabcmd.?.strsize - 1 :0];
-            const symtab = @as(
-                [*]const macho.nlist_64,
-                @ptrCast(@alignCast(&mapped_mem[symtabcmd.?.symoff])),
-            )[0..symtabcmd.?.nsyms];
-
-            // TODO handle tentative (common) symbols
-            var addr_table = std.StringHashMap(u64).init(allocator);
-            try addr_table.ensureTotalCapacity(@as(u32, @intCast(symtab.len)));
-            for (symtab) |sym| {
-                if (sym.n_strx == 0) continue;
-                if (sym.undf() or sym.tentative() or sym.abs()) continue;
-                const sym_name = mem.sliceTo(strtab[sym.n_strx..], 0);
-                // TODO is it possible to have a symbol collision?
-                addr_table.putAssumeCapacityNoClobber(sym_name, sym.n_value);
-            }
-
-            var sections: Dwarf.SectionArray = Dwarf.null_section_array;
-            if (self.eh_frame) |eh_frame| sections[@intFromEnum(Dwarf.Section.Id.eh_frame)] = .{
-                .data = eh_frame,
-                .owned = false,
-            };
-
-            for (segcmd.?.getSections()) |sect| {
-                if (!std.mem.eql(u8, "__DWARF", sect.segName())) continue;
-
-                var section_index: ?usize = null;
-                inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
-                    if (mem.eql(u8, "__" ++ section.name, sect.sectName())) section_index = i;
-                }
-                if (section_index == null) continue;
-
-                const section_bytes = try chopSlice(mapped_mem, sect.offset, sect.size);
-                sections[section_index.?] = .{
-                    .data = section_bytes,
-                    .virtual_address = sect.addr,
-                    .owned = false,
-                };
-            }
-
-            const missing_debug_info =
-                sections[@intFromEnum(Dwarf.Section.Id.debug_info)] == null or
-                sections[@intFromEnum(Dwarf.Section.Id.debug_abbrev)] == null or
-                sections[@intFromEnum(Dwarf.Section.Id.debug_str)] == null or
-                sections[@intFromEnum(Dwarf.Section.Id.debug_line)] == null;
-            if (missing_debug_info) return error.MissingDebugInfo;
-
-            var di = Dwarf{
-                .endian = .little,
-                .sections = sections,
-                .is_macho = true,
-            };
-
-            try Dwarf.open(&di, allocator);
-            const info = OFileInfo{
-                .di = di,
-                .addr_table = addr_table,
-            };
-
-            // Add the debug info to the cache
-            const result = try self.ofiles.getOrPut(o_file_path);
-            assert(!result.found_existing);
-            result.value_ptr.* = info;
-
-            return result.value_ptr;
-        }
-
-        pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
-            nosuspend {
-                const result = try self.getOFileInfoForAddress(allocator, address);
-                if (result.symbol == null) return .{};
-
-                // Take the symbol name from the N_FUN STAB entry, we're going to
-                // use it if we fail to find the DWARF infos
-                const stab_symbol = mem.sliceTo(self.strings[result.symbol.?.strx..], 0);
-                if (result.o_file_info == null) return .{ .symbol_name = stab_symbol };
-
-                // Translate again the address, this time into an address inside the
-                // .o file
-                const relocated_address_o = result.o_file_info.?.addr_table.get(stab_symbol) orelse return .{
-                    .symbol_name = "???",
-                };
-
-                const addr_off = result.relocated_address - result.symbol.?.addr;
-                const o_file_di = &result.o_file_info.?.di;
-                if (o_file_di.findCompileUnit(relocated_address_o)) |compile_unit| {
-                    return SymbolInfo{
-                        .symbol_name = o_file_di.getSymbolName(relocated_address_o) orelse "???",
-                        .compile_unit_name = compile_unit.die.getAttrString(
-                            o_file_di,
-                            DW.AT.name,
-                            o_file_di.section(.debug_str),
-                            compile_unit.*,
-                        ) catch |err| switch (err) {
-                            error.MissingDebugInfo, error.InvalidDebugInfo => "???",
-                        },
-                        .line_info = o_file_di.getLineNumberInfo(
-                            allocator,
-                            compile_unit.*,
-                            relocated_address_o + addr_off,
-                        ) catch |err| switch (err) {
-                            error.MissingDebugInfo, error.InvalidDebugInfo => null,
-                            else => return err,
-                        },
-                    };
-                } else |err| switch (err) {
-                    error.MissingDebugInfo, error.InvalidDebugInfo => {
-                        return SymbolInfo{ .symbol_name = stab_symbol };
-                    },
-                    else => return err,
-                }
-            }
-        }
-
-        pub fn getOFileInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !struct {
-            relocated_address: usize,
-            symbol: ?*const MachoSymbol = null,
-            o_file_info: ?*OFileInfo = null,
-        } {
-            nosuspend {
-                // Translate the VA into an address into this object
-                const relocated_address = address - self.vmaddr_slide;
-
-                // Find the .o file where this symbol is defined
-                const symbol = machoSearchSymbols(self.symbols, relocated_address) orelse return .{
-                    .relocated_address = relocated_address,
-                };
-
-                // Check if its debug infos are already in the cache
-                const o_file_path = mem.sliceTo(self.strings[symbol.ofile..], 0);
-                const o_file_info = self.ofiles.getPtr(o_file_path) orelse
-                    (self.loadOFile(allocator, o_file_path) catch |err| switch (err) {
-                    error.FileNotFound,
-                    error.MissingDebugInfo,
-                    error.InvalidDebugInfo,
-                    => return .{
-                        .relocated_address = relocated_address,
-                        .symbol = symbol,
-                    },
-                    else => return err,
-                });
-
-                return .{
-                    .relocated_address = relocated_address,
-                    .symbol = symbol,
-                    .o_file_info = o_file_info,
-                };
-            }
-        }
-
-        pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
-            return if ((try self.getOFileInfoForAddress(allocator, address)).o_file_info) |o_file_info| &o_file_info.di else null;
-        }
-    },
-    .uefi, .windows => struct {
-        base_address: usize,
-        pdb: ?pdb.Pdb = null,
-        dwarf: ?Dwarf = null,
-        coff_image_base: u64,
-
-        /// Only used if pdb is non-null
-        coff_section_headers: []coff.SectionHeader,
-
-        pub fn deinit(self: *@This(), allocator: mem.Allocator) void {
-            if (self.dwarf) |*dwarf| {
-                dwarf.deinit(allocator);
-            }
-
-            if (self.pdb) |*p| {
-                p.deinit();
-                allocator.free(self.coff_section_headers);
-            }
-        }
-
-        fn getSymbolFromPdb(self: *@This(), relocated_address: usize) !?SymbolInfo {
-            var coff_section: *align(1) const coff.SectionHeader = undefined;
-            const mod_index = for (self.pdb.?.sect_contribs) |sect_contrib| {
-                if (sect_contrib.Section > self.coff_section_headers.len) continue;
-                // Remember that SectionContribEntry.Section is 1-based.
-                coff_section = &self.coff_section_headers[sect_contrib.Section - 1];
-
-                const vaddr_start = coff_section.virtual_address + sect_contrib.Offset;
-                const vaddr_end = vaddr_start + sect_contrib.Size;
-                if (relocated_address >= vaddr_start and relocated_address < vaddr_end) {
-                    break sect_contrib.ModuleIndex;
-                }
-            } else {
-                // we have no information to add to the address
-                return null;
-            };
-
-            const module = (try self.pdb.?.getModule(mod_index)) orelse
-                return error.InvalidDebugInfo;
-            const obj_basename = fs.path.basename(module.obj_file_name);
-
-            const symbol_name = self.pdb.?.getSymbolName(
-                module,
-                relocated_address - coff_section.virtual_address,
-            ) orelse "???";
-            const opt_line_info = try self.pdb.?.getLineNumberInfo(
-                module,
-                relocated_address - coff_section.virtual_address,
-            );
-
-            return SymbolInfo{
-                .symbol_name = symbol_name,
-                .compile_unit_name = obj_basename,
-                .line_info = opt_line_info,
-            };
-        }
-
-        pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
-            // Translate the VA into an address into this object
-            const relocated_address = address - self.base_address;
-
-            if (self.pdb != null) {
-                if (try self.getSymbolFromPdb(relocated_address)) |symbol| return symbol;
-            }
-
-            if (self.dwarf) |*dwarf| {
-                const dwarf_address = relocated_address + self.coff_image_base;
-                return getSymbolFromDwarf(allocator, dwarf_address, dwarf);
-            }
-
-            return SymbolInfo{};
-        }
-
-        pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
-            _ = allocator;
-            _ = address;
-
-            return switch (self.debug_data) {
-                .dwarf => |*dwarf| dwarf,
-                else => null,
-            };
-        }
-    },
-    .linux, .netbsd, .freebsd, .dragonfly, .openbsd, .haiku, .solaris, .illumos => struct {
-        base_address: usize,
-        dwarf: Dwarf,
-        mapped_memory: []align(mem.page_size) const u8,
-        external_mapped_memory: ?[]align(mem.page_size) const u8,
-
-        pub fn deinit(self: *@This(), allocator: mem.Allocator) void {
-            self.dwarf.deinit(allocator);
-            posix.munmap(self.mapped_memory);
-            if (self.external_mapped_memory) |m| posix.munmap(m);
-        }
-
-        pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
-            // Translate the VA into an address into this object
-            const relocated_address = address - self.base_address;
-            return getSymbolFromDwarf(allocator, relocated_address, &self.dwarf);
-        }
-
-        pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
-            _ = allocator;
-            _ = address;
-            return &self.dwarf;
-        }
-    },
-    .wasi, .emscripten => struct {
-        pub fn deinit(self: *@This(), allocator: mem.Allocator) void {
-            _ = self;
-            _ = allocator;
-        }
-
-        pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
-            _ = self;
-            _ = allocator;
-            _ = address;
-            return SymbolInfo{};
-        }
-
-        pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
-            _ = self;
-            _ = allocator;
-            _ = address;
-            return null;
-        }
-    },
-    else => Dwarf,
-};
-
-fn getSymbolFromDwarf(allocator: mem.Allocator, address: u64, di: *Dwarf) !SymbolInfo {
-    if (nosuspend di.findCompileUnit(address)) |compile_unit| {
-        return SymbolInfo{
-            .symbol_name = nosuspend di.getSymbolName(address) orelse "???",
-            .compile_unit_name = compile_unit.die.getAttrString(di, DW.AT.name, di.section(.debug_str), compile_unit.*) catch |err| switch (err) {
-                error.MissingDebugInfo, error.InvalidDebugInfo => "???",
-            },
-            .line_info = nosuspend di.getLineNumberInfo(allocator, compile_unit.*, address) catch |err| switch (err) {
-                error.MissingDebugInfo, error.InvalidDebugInfo => null,
-                else => return err,
-            },
-        };
-    } else |err| switch (err) {
-        error.MissingDebugInfo, error.InvalidDebugInfo => {
-            return SymbolInfo{};
-        },
-        else => return err,
-    }
-}
-
 /// TODO multithreaded awareness
 var debug_info_allocator: ?mem.Allocator = null;
 var debug_info_arena_allocator: std.heap.ArenaAllocator = undefined;
@@ -2687,7 +1229,7 @@ fn handleSegfaultPosix(sig: i32, info: *const posix.siginfo_t, ctx_ptr: ?*anyopa
     posix.abort();
 }
 
-fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*const anyopaque) void {
+fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*anyopaque) void {
     const stderr = io.getStdErr().writer();
     _ = switch (sig) {
         posix.SIG.SEGV => if (native_arch == .x86_64 and native_os == .linux and code == 128) // SI_KERNEL
@@ -2713,7 +1255,7 @@ fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*const anyo
         .arm,
         .aarch64,
         => {
-            const ctx: *const posix.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
+            const ctx: *posix.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
             dumpStackTraceFromBase(ctx);
         },
         else => {},
@@ -2802,7 +1344,7 @@ test "manage resources correctly" {
     }
 
     const writer = std.io.null_writer;
-    var di = try openSelfDebugInfo(testing.allocator);
+    var di = try SelfInfo.open(testing.allocator);
     defer di.deinit();
     try printSourceAtAddress(&di, writer, showMyTrace(), io.tty.detectConfig(std.io.getStdErr()));
 }
@@ -2939,6 +1481,99 @@ pub const SafetyLock = struct {
     }
 };
 
+/// Deprecated. Don't use this, just read from your memory directly.
+///
+/// This only exists because someone was too lazy to rework logic that used to
+/// operate on an open file to operate on a memory buffer instead.
+pub const DeprecatedFixedBufferReader = struct {
+    buf: []const u8,
+    pos: usize = 0,
+    endian: std.builtin.Endian,
+
+    pub const Error = error{ EndOfBuffer, Overflow, InvalidBuffer };
+
+    pub fn seekTo(fbr: *DeprecatedFixedBufferReader, pos: u64) Error!void {
+        if (pos > fbr.buf.len) return error.EndOfBuffer;
+        fbr.pos = @intCast(pos);
+    }
+
+    pub fn seekForward(fbr: *DeprecatedFixedBufferReader, amount: u64) Error!void {
+        if (fbr.buf.len - fbr.pos < amount) return error.EndOfBuffer;
+        fbr.pos += @intCast(amount);
+    }
+
+    pub inline fn readByte(fbr: *DeprecatedFixedBufferReader) Error!u8 {
+        if (fbr.pos >= fbr.buf.len) return error.EndOfBuffer;
+        defer fbr.pos += 1;
+        return fbr.buf[fbr.pos];
+    }
+
+    pub fn readByteSigned(fbr: *DeprecatedFixedBufferReader) Error!i8 {
+        return @bitCast(try fbr.readByte());
+    }
+
+    pub fn readInt(fbr: *DeprecatedFixedBufferReader, comptime T: type) Error!T {
+        const size = @divExact(@typeInfo(T).Int.bits, 8);
+        if (fbr.buf.len - fbr.pos < size) return error.EndOfBuffer;
+        defer fbr.pos += size;
+        return std.mem.readInt(T, fbr.buf[fbr.pos..][0..size], fbr.endian);
+    }
+
+    pub fn readIntChecked(
+        fbr: *DeprecatedFixedBufferReader,
+        comptime T: type,
+        ma: *MemoryAccessor,
+    ) Error!T {
+        if (ma.load(T, @intFromPtr(fbr.buf[fbr.pos..].ptr)) == null)
+            return error.InvalidBuffer;
+
+        return fbr.readInt(T);
+    }
+
+    pub fn readUleb128(fbr: *DeprecatedFixedBufferReader, comptime T: type) Error!T {
+        return std.leb.readUleb128(T, fbr);
+    }
+
+    pub fn readIleb128(fbr: *DeprecatedFixedBufferReader, comptime T: type) Error!T {
+        return std.leb.readIleb128(T, fbr);
+    }
+
+    pub fn readAddress(fbr: *DeprecatedFixedBufferReader, format: std.dwarf.Format) Error!u64 {
+        return switch (format) {
+            .@"32" => try fbr.readInt(u32),
+            .@"64" => try fbr.readInt(u64),
+        };
+    }
+
+    pub fn readAddressChecked(
+        fbr: *DeprecatedFixedBufferReader,
+        format: std.dwarf.Format,
+        ma: *MemoryAccessor,
+    ) Error!u64 {
+        return switch (format) {
+            .@"32" => try fbr.readIntChecked(u32, ma),
+            .@"64" => try fbr.readIntChecked(u64, ma),
+        };
+    }
+
+    pub fn readBytes(fbr: *DeprecatedFixedBufferReader, len: usize) Error![]const u8 {
+        if (fbr.buf.len - fbr.pos < len) return error.EndOfBuffer;
+        defer fbr.pos += len;
+        return fbr.buf[fbr.pos..][0..len];
+    }
+
+    pub fn readBytesTo(fbr: *DeprecatedFixedBufferReader, comptime sentinel: u8) Error![:sentinel]const u8 {
+        const end = @call(.always_inline, std.mem.indexOfScalarPos, .{
+            u8,
+            fbr.buf,
+            fbr.pos,
+            sentinel,
+        }) orelse return error.EndOfBuffer;
+        defer fbr.pos = end + 1;
+        return fbr.buf[fbr.pos..end :sentinel];
+    }
+};
+
 /// Detect whether the program is being executed in the Valgrind virtual machine.
 ///
 /// When Valgrind integrations are disabled, this returns comptime-known false.
@@ -2950,5 +1585,9 @@ pub inline fn inValgrind() bool {
 }
 
 test {
+    _ = &Dwarf;
+    _ = &MemoryAccessor;
+    _ = &Pdb;
+    _ = &SelfInfo;
     _ = &dumpHex;
 }
diff --git a/lib/std/debug/Dwarf.zig b/lib/std/debug/Dwarf.zig
index f17fd737a1..991c731549 100644
--- a/lib/std/debug/Dwarf.zig
+++ b/lib/std/debug/Dwarf.zig
@@ -1,23 +1,32 @@
 //! Implements parsing, decoding, and caching of DWARF information.
 //!
+//! This API does not assume the current executable is itself the thing being
+//! debugged, however, it does assume the debug info has the same CPU
+//! architecture and OS as the current executable. It is planned to remove this
+//! limitation.
+//!
 //! For unopinionated types and bits, see `std.dwarf`.
 
 const builtin = @import("builtin");
+const native_endian = builtin.cpu.arch.endian();
+
 const std = @import("../std.zig");
-const AT = DW.AT;
 const Allocator = std.mem.Allocator;
 const DW = std.dwarf;
+const AT = DW.AT;
 const EH = DW.EH;
 const FORM = DW.FORM;
 const Format = DW.Format;
 const RLE = DW.RLE;
-const StackIterator = std.debug.StackIterator;
 const UT = DW.UT;
 const assert = std.debug.assert;
 const cast = std.math.cast;
 const maxInt = std.math.maxInt;
-const native_endian = builtin.cpu.arch.endian();
 const readInt = std.mem.readInt;
+const MemoryAccessor = std.debug.MemoryAccessor;
+
+/// Did I mention this is deprecated?
+const DeprecatedFixedBufferReader = std.debug.DeprecatedFixedBufferReader;
 
 const Dwarf = @This();
 
@@ -153,7 +162,7 @@ pub const FormValue = union(enum) {
             .string => |s| return s,
             .strp => |off| return di.getString(off),
             .line_strp => |off| return di.getLineString(off),
-            else => return badDwarf(),
+            else => return bad(),
         }
     }
 
@@ -162,8 +171,8 @@ pub const FormValue = union(enum) {
             inline .udata,
             .sdata,
             .sec_offset,
-            => |c| cast(U, c) orelse badDwarf(),
-            else => badDwarf(),
+            => |c| cast(U, c) orelse bad(),
+            else => bad(),
         };
     }
 };
@@ -237,25 +246,25 @@ pub const Die = struct {
             .string => |value| return value,
             .strp => |offset| return di.getString(offset),
             .strx => |index| {
-                const debug_str_offsets = di.section(.debug_str_offsets) orelse return badDwarf();
-                if (compile_unit.str_offsets_base == 0) return badDwarf();
+                const debug_str_offsets = di.section(.debug_str_offsets) orelse return bad();
+                if (compile_unit.str_offsets_base == 0) return bad();
                 switch (compile_unit.format) {
                     .@"32" => {
                         const byte_offset = compile_unit.str_offsets_base + 4 * index;
-                        if (byte_offset + 4 > debug_str_offsets.len) return badDwarf();
+                        if (byte_offset + 4 > debug_str_offsets.len) return bad();
                         const offset = readInt(u32, debug_str_offsets[byte_offset..][0..4], di.endian);
                         return getStringGeneric(opt_str, offset);
                     },
                     .@"64" => {
                         const byte_offset = compile_unit.str_offsets_base + 8 * index;
-                        if (byte_offset + 8 > debug_str_offsets.len) return badDwarf();
+                        if (byte_offset + 8 > debug_str_offsets.len) return bad();
                         const offset = readInt(u64, debug_str_offsets[byte_offset..][0..8], di.endian);
                         return getStringGeneric(opt_str, offset);
                     },
                 }
             },
             .line_strp => |offset| return di.getLineString(offset),
-            else => return badDwarf(),
+            else => return bad(),
         }
     }
 };
@@ -279,7 +288,7 @@ pub const ExceptionFrameHeader = struct {
             EH.PE.sdata8,
             => 16,
             // This is a binary search table, so all entries must be the same length
-            else => return badDwarf(),
+            else => return bad(),
         };
     }
 
@@ -287,7 +296,7 @@ pub const ExceptionFrameHeader = struct {
         self: ExceptionFrameHeader,
         comptime T: type,
         ptr: usize,
-        ma: *StackIterator.MemoryAccessor,
+        ma: *MemoryAccessor,
         eh_frame_len: ?usize,
     ) bool {
         if (eh_frame_len) |len| {
@@ -304,7 +313,7 @@ pub const ExceptionFrameHeader = struct {
     /// If `eh_frame_len` is provided, then these checks can be skipped.
     pub fn findEntry(
         self: ExceptionFrameHeader,
-        ma: *StackIterator.MemoryAccessor,
+        ma: *MemoryAccessor,
         eh_frame_len: ?usize,
         eh_frame_hdr_ptr: usize,
         pc: usize,
@@ -316,7 +325,7 @@ pub const ExceptionFrameHeader = struct {
         var left: usize = 0;
         var len: usize = self.fde_count;
 
-        var fbr: FixedBufferReader = .{ .buf = self.entries, .endian = native_endian };
+        var fbr: DeprecatedFixedBufferReader = .{ .buf = self.entries, .endian = native_endian };
 
         while (len > 1) {
             const mid = left + len / 2;
@@ -326,7 +335,7 @@ pub const ExceptionFrameHeader = struct {
                 .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
                 .follow_indirect = true,
                 .data_rel_base = eh_frame_hdr_ptr,
-            }) orelse return badDwarf();
+            }) orelse return bad();
 
             if (pc < pc_begin) {
                 len /= 2;
@@ -337,7 +346,7 @@ pub const ExceptionFrameHeader = struct {
             }
         }
 
-        if (len == 0) return badDwarf();
+        if (len == 0) return bad();
         fbr.pos = left * entry_size;
 
         // Read past the pc_begin field of the entry
@@ -345,36 +354,36 @@ pub const ExceptionFrameHeader = struct {
             .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
             .follow_indirect = true,
             .data_rel_base = eh_frame_hdr_ptr,
-        }) orelse return badDwarf();
+        }) orelse return bad();
 
         const fde_ptr = cast(usize, try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
             .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
             .follow_indirect = true,
             .data_rel_base = eh_frame_hdr_ptr,
-        }) orelse return badDwarf()) orelse return badDwarf();
+        }) orelse return bad()) orelse return bad();
 
-        if (fde_ptr < self.eh_frame_ptr) return badDwarf();
+        if (fde_ptr < self.eh_frame_ptr) return bad();
 
         // Even if eh_frame_len is not specified, all ranges accssed are checked via MemoryAccessor
         const eh_frame = @as([*]const u8, @ptrFromInt(self.eh_frame_ptr))[0 .. eh_frame_len orelse maxInt(u32)];
 
         const fde_offset = fde_ptr - self.eh_frame_ptr;
-        var eh_frame_fbr: FixedBufferReader = .{
+        var eh_frame_fbr: DeprecatedFixedBufferReader = .{
             .buf = eh_frame,
             .pos = fde_offset,
             .endian = native_endian,
         };
 
         const fde_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
-        if (!self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
-        if (fde_entry_header.type != .fde) return badDwarf();
+        if (!self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return bad();
+        if (fde_entry_header.type != .fde) return bad();
 
         // CIEs always come before FDEs (the offset is a subtraction), so we can assume this memory is readable
         const cie_offset = fde_entry_header.type.fde;
         try eh_frame_fbr.seekTo(cie_offset);
         const cie_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
-        if (!self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
-        if (cie_entry_header.type != .cie) return badDwarf();
+        if (!self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return bad();
+        if (cie_entry_header.type != .cie) return bad();
 
         cie.* = try CommonInformationEntry.parse(
             cie_entry_header.entry_bytes,
@@ -417,17 +426,17 @@ pub const EntryHeader = struct {
     }
 
     /// Reads a header for either an FDE or a CIE, then advances the fbr to the position after the trailing structure.
-    /// `fbr` must be a FixedBufferReader backed by either the .eh_frame or .debug_frame sections.
+    /// `fbr` must be a DeprecatedFixedBufferReader backed by either the .eh_frame or .debug_frame sections.
     pub fn read(
-        fbr: *FixedBufferReader,
-        opt_ma: ?*StackIterator.MemoryAccessor,
+        fbr: *DeprecatedFixedBufferReader,
+        opt_ma: ?*MemoryAccessor,
         dwarf_section: Section.Id,
     ) !EntryHeader {
         assert(dwarf_section == .eh_frame or dwarf_section == .debug_frame);
 
         const length_offset = fbr.pos;
         const unit_header = try readUnitHeader(fbr, opt_ma);
-        const unit_length = cast(usize, unit_header.unit_length) orelse return badDwarf();
+        const unit_length = cast(usize, unit_header.unit_length) orelse return bad();
         if (unit_length == 0) return .{
             .length_offset = length_offset,
             .format = unit_header.format,
@@ -532,7 +541,7 @@ pub const CommonInformationEntry = struct {
     ) !CommonInformationEntry {
         if (addr_size_bytes > 8) return error.UnsupportedAddrSize;
 
-        var fbr: FixedBufferReader = .{ .buf = cie_bytes, .endian = endian };
+        var fbr: DeprecatedFixedBufferReader = .{ .buf = cie_bytes, .endian = endian };
 
         const version = try fbr.readByte();
         switch (dwarf_section) {
@@ -550,15 +559,15 @@ pub const CommonInformationEntry = struct {
         while (aug_byte != 0) : (aug_byte = try fbr.readByte()) {
             switch (aug_byte) {
                 'z' => {
-                    if (aug_str_len != 0) return badDwarf();
+                    if (aug_str_len != 0) return bad();
                     has_aug_data = true;
                 },
                 'e' => {
-                    if (has_aug_data or aug_str_len != 0) return badDwarf();
-                    if (try fbr.readByte() != 'h') return badDwarf();
+                    if (has_aug_data or aug_str_len != 0) return bad();
+                    if (try fbr.readByte() != 'h') return bad();
                     has_eh_data = true;
                 },
-                else => if (has_eh_data) return badDwarf(),
+                else => if (has_eh_data) return bad(),
             }
 
             aug_str_len += 1;
@@ -604,7 +613,7 @@ pub const CommonInformationEntry = struct {
                         fde_pointer_enc = try fbr.readByte();
                     },
                     'S', 'B', 'G' => {},
-                    else => return badDwarf(),
+                    else => return bad(),
                 }
             }
 
@@ -666,17 +675,17 @@ pub const FrameDescriptionEntry = struct {
     ) !FrameDescriptionEntry {
         if (addr_size_bytes > 8) return error.InvalidAddrSize;
 
-        var fbr: FixedBufferReader = .{ .buf = fde_bytes, .endian = endian };
+        var fbr: DeprecatedFixedBufferReader = .{ .buf = fde_bytes, .endian = endian };
 
         const pc_begin = try readEhPointer(&fbr, cie.fde_pointer_enc, addr_size_bytes, .{
             .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[fbr.pos]), pc_rel_offset),
             .follow_indirect = is_runtime,
-        }) orelse return badDwarf();
+        }) orelse return bad();
 
         const pc_range = try readEhPointer(&fbr, cie.fde_pointer_enc, addr_size_bytes, .{
             .pc_rel_base = 0,
             .follow_indirect = false,
-        }) orelse return badDwarf();
+        }) orelse return bad();
 
         var aug_data: []const u8 = &[_]u8{};
         const lsda_pointer = if (cie.aug_str.len > 0) blk: {
@@ -708,54 +717,6 @@ pub const FrameDescriptionEntry = struct {
     }
 };
 
-pub const UnwindContext = struct {
-    allocator: Allocator,
-    cfa: ?usize,
-    pc: usize,
-    thread_context: *std.debug.ThreadContext,
-    reg_context: abi.RegisterContext,
-    vm: call_frame.VirtualMachine,
-    stack_machine: expression.StackMachine(.{ .call_frame_context = true }),
-
-    pub fn init(
-        allocator: Allocator,
-        thread_context: *const std.debug.ThreadContext,
-    ) !UnwindContext {
-        const pc = abi.stripInstructionPtrAuthCode(
-            (try abi.regValueNative(
-                usize,
-                thread_context,
-                abi.ipRegNum(),
-                null,
-            )).*,
-        );
-
-        const context_copy = try allocator.create(std.debug.ThreadContext);
-        std.debug.copyContext(thread_context, context_copy);
-
-        return .{
-            .allocator = allocator,
-            .cfa = null,
-            .pc = pc,
-            .thread_context = context_copy,
-            .reg_context = undefined,
-            .vm = .{},
-            .stack_machine = .{},
-        };
-    }
-
-    pub fn deinit(self: *UnwindContext) void {
-        self.vm.deinit(self.allocator);
-        self.stack_machine.deinit(self.allocator);
-        self.allocator.destroy(self.thread_context);
-        self.* = undefined;
-    }
-
-    pub fn getFp(self: *const UnwindContext) !usize {
-        return (try abi.regValueNative(usize, self.thread_context, abi.fpRegNum(self.reg_context), self.reg_context)).*;
-    }
-};
-
 const num_sections = std.enums.directEnumArrayLen(Section.Id, 0);
 pub const SectionArray = [num_sections]?Section;
 pub const null_section_array = [_]?Section{null} ** num_sections;
@@ -817,7 +778,7 @@ pub fn getSymbolName(di: *Dwarf, address: u64) ?[]const u8 {
 }
 
 fn scanAllFunctions(di: *Dwarf, allocator: Allocator) !void {
-    var fbr: FixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
+    var fbr: DeprecatedFixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
     var this_unit_offset: u64 = 0;
 
     while (this_unit_offset < fbr.buf.len) {
@@ -828,20 +789,20 @@ fn scanAllFunctions(di: *Dwarf, allocator: Allocator) !void {
         const next_offset = unit_header.header_length + unit_header.unit_length;
 
         const version = try fbr.readInt(u16);
-        if (version < 2 or version > 5) return badDwarf();
+        if (version < 2 or version > 5) return bad();
 
         var address_size: u8 = undefined;
         var debug_abbrev_offset: u64 = undefined;
         if (version >= 5) {
             const unit_type = try fbr.readInt(u8);
-            if (unit_type != DW.UT.compile) return badDwarf();
+            if (unit_type != DW.UT.compile) return bad();
             address_size = try fbr.readByte();
             debug_abbrev_offset = try fbr.readAddress(unit_header.format);
         } else {
             debug_abbrev_offset = try fbr.readAddress(unit_header.format);
             address_size = try fbr.readByte();
         }
-        if (address_size != @sizeOf(usize)) return badDwarf();
+        if (address_size != @sizeOf(usize)) return bad();
 
         const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
 
@@ -915,28 +876,28 @@ fn scanAllFunctions(di: *Dwarf, allocator: Allocator) !void {
 
                                 // Follow the DIE it points to and repeat
                                 const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin);
-                                if (ref_offset > next_offset) return badDwarf();
+                                if (ref_offset > next_offset) return bad();
                                 try fbr.seekTo(this_unit_offset + ref_offset);
                                 this_die_obj = (try parseDie(
                                     &fbr,
                                     attrs_bufs[2],
                                     abbrev_table,
                                     unit_header.format,
-                                )) orelse return badDwarf();
+                                )) orelse return bad();
                             } else if (this_die_obj.getAttr(AT.specification)) |_| {
                                 const after_die_offset = fbr.pos;
                                 defer fbr.pos = after_die_offset;
 
                                 // Follow the DIE it points to and repeat
                                 const ref_offset = try this_die_obj.getAttrRef(AT.specification);
-                                if (ref_offset > next_offset) return badDwarf();
+                                if (ref_offset > next_offset) return bad();
                                 try fbr.seekTo(this_unit_offset + ref_offset);
                                 this_die_obj = (try parseDie(
                                     &fbr,
                                     attrs_bufs[2],
                                     abbrev_table,
                                     unit_header.format,
-                                )) orelse return badDwarf();
+                                )) orelse return bad();
                             } else {
                                 break :x null;
                             }
@@ -950,7 +911,7 @@ fn scanAllFunctions(di: *Dwarf, allocator: Allocator) !void {
                             const pc_end = switch (high_pc_value.*) {
                                 .addr => |value| value,
                                 .udata => |offset| low_pc + offset,
-                                else => return badDwarf(),
+                                else => return bad(),
                             };
 
                             try di.func_list.append(allocator, .{
@@ -1004,7 +965,7 @@ fn scanAllFunctions(di: *Dwarf, allocator: Allocator) !void {
 }
 
 fn scanAllCompileUnits(di: *Dwarf, allocator: Allocator) !void {
-    var fbr: FixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
+    var fbr: DeprecatedFixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
     var this_unit_offset: u64 = 0;
 
     var attrs_buf = std.ArrayList(Die.Attr).init(allocator);
@@ -1018,20 +979,20 @@ fn scanAllCompileUnits(di: *Dwarf, allocator: Allocator) !void {
         const next_offset = unit_header.header_length + unit_header.unit_length;
 
         const version = try fbr.readInt(u16);
-        if (version < 2 or version > 5) return badDwarf();
+        if (version < 2 or version > 5) return bad();
 
         var address_size: u8 = undefined;
         var debug_abbrev_offset: u64 = undefined;
         if (version >= 5) {
             const unit_type = try fbr.readInt(u8);
-            if (unit_type != UT.compile) return badDwarf();
+            if (unit_type != UT.compile) return bad();
             address_size = try fbr.readByte();
             debug_abbrev_offset = try fbr.readAddress(unit_header.format);
         } else {
             debug_abbrev_offset = try fbr.readAddress(unit_header.format);
             address_size = try fbr.readByte();
         }
-        if (address_size != @sizeOf(usize)) return badDwarf();
+        if (address_size != @sizeOf(usize)) return bad();
 
         const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
 
@@ -1046,9 +1007,9 @@ fn scanAllCompileUnits(di: *Dwarf, allocator: Allocator) !void {
             attrs_buf.items,
             abbrev_table,
             unit_header.format,
-        )) orelse return badDwarf();
+        )) orelse return bad();
 
-        if (compile_unit_die.tag_id != DW.TAG.compile_unit) return badDwarf();
+        if (compile_unit_die.tag_id != DW.TAG.compile_unit) return bad();
 
         compile_unit_die.attrs = try allocator.dupe(Die.Attr, compile_unit_die.attrs);
 
@@ -1070,7 +1031,7 @@ fn scanAllCompileUnits(di: *Dwarf, allocator: Allocator) !void {
                     const pc_end = switch (high_pc_value.*) {
                         .addr => |value| value,
                         .udata => |offset| low_pc + offset,
-                        else => return badDwarf(),
+                        else => return bad(),
                     };
                     break :x PcRange{
                         .start = low_pc,
@@ -1096,7 +1057,7 @@ const DebugRangeIterator = struct {
     section_type: Section.Id,
     di: *const Dwarf,
     compile_unit: *const CompileUnit,
-    fbr: FixedBufferReader,
+    fbr: DeprecatedFixedBufferReader,
 
     pub fn init(ranges_value: *const FormValue, di: *const Dwarf, compile_unit: *const CompileUnit) !@This() {
         const section_type = if (compile_unit.version >= 5) Section.Id.debug_rnglists else Section.Id.debug_ranges;
@@ -1108,19 +1069,19 @@ const DebugRangeIterator = struct {
                 switch (compile_unit.format) {
                     .@"32" => {
                         const offset_loc = @as(usize, @intCast(compile_unit.rnglists_base + 4 * idx));
-                        if (offset_loc + 4 > debug_ranges.len) return badDwarf();
+                        if (offset_loc + 4 > debug_ranges.len) return bad();
                         const offset = readInt(u32, debug_ranges[offset_loc..][0..4], di.endian);
                         break :off compile_unit.rnglists_base + offset;
                     },
                     .@"64" => {
                         const offset_loc = @as(usize, @intCast(compile_unit.rnglists_base + 8 * idx));
-                        if (offset_loc + 8 > debug_ranges.len) return badDwarf();
+                        if (offset_loc + 8 > debug_ranges.len) return bad();
                         const offset = readInt(u64, debug_ranges[offset_loc..][0..8], di.endian);
                         break :off compile_unit.rnglists_base + offset;
                     },
                 }
             },
-            else => return badDwarf(),
+            else => return bad(),
         };
 
         // All the addresses in the list are relative to the value
@@ -1139,7 +1100,7 @@ const DebugRangeIterator = struct {
             .compile_unit = compile_unit,
             .fbr = .{
                 .buf = debug_ranges,
-                .pos = cast(usize, ranges_offset) orelse return badDwarf(),
+                .pos = cast(usize, ranges_offset) orelse return bad(),
                 .endian = di.endian,
             },
         };
@@ -1214,7 +1175,7 @@ const DebugRangeIterator = struct {
                             .end_addr = end_addr,
                         };
                     },
-                    else => return badDwarf(),
+                    else => return bad(),
                 }
             },
             .debug_ranges => {
@@ -1251,7 +1212,7 @@ pub fn findCompileUnit(di: *const Dwarf, target_address: u64) !*const CompileUni
         }
     }
 
-    return missingDwarf();
+    return missing();
 }
 
 /// Gets an already existing AbbrevTable given the abbrev_offset, or if not found,
@@ -1270,9 +1231,9 @@ fn getAbbrevTable(di: *Dwarf, allocator: Allocator, abbrev_offset: u64) !*const
 }
 
 fn parseAbbrevTable(di: *Dwarf, allocator: Allocator, offset: u64) !Abbrev.Table {
-    var fbr: FixedBufferReader = .{
+    var fbr: DeprecatedFixedBufferReader = .{
         .buf = di.section(.debug_abbrev).?,
-        .pos = cast(usize, offset) orelse return badDwarf(),
+        .pos = cast(usize, offset) orelse return bad(),
         .endian = di.endian,
     };
 
@@ -1322,14 +1283,14 @@ fn parseAbbrevTable(di: *Dwarf, allocator: Allocator, offset: u64) !Abbrev.Table
 }
 
 fn parseDie(
-    fbr: *FixedBufferReader,
+    fbr: *DeprecatedFixedBufferReader,
     attrs_buf: []Die.Attr,
     abbrev_table: *const Abbrev.Table,
     format: Format,
 ) !?Die {
     const abbrev_code = try fbr.readUleb128(u64);
     if (abbrev_code == 0) return null;
-    const table_entry = abbrev_table.get(abbrev_code) orelse return badDwarf();
+    const table_entry = abbrev_table.get(abbrev_code) orelse return bad();
 
     const attrs = attrs_buf[0..table_entry.attrs.len];
     for (attrs, table_entry.attrs) |*result_attr, attr| result_attr.* = Die.Attr{
@@ -1353,19 +1314,19 @@ pub fn getLineNumberInfo(
     allocator: Allocator,
     compile_unit: CompileUnit,
     target_address: u64,
-) !std.debug.LineInfo {
+) !std.debug.SourceLocation {
     const compile_unit_cwd = try compile_unit.die.getAttrString(di, AT.comp_dir, di.section(.debug_line_str), compile_unit);
     const line_info_offset = try compile_unit.die.getAttrSecOffset(AT.stmt_list);
 
-    var fbr: FixedBufferReader = .{ .buf = di.section(.debug_line).?, .endian = di.endian };
+    var fbr: DeprecatedFixedBufferReader = .{ .buf = di.section(.debug_line).?, .endian = di.endian };
     try fbr.seekTo(line_info_offset);
 
     const unit_header = try readUnitHeader(&fbr, null);
-    if (unit_header.unit_length == 0) return missingDwarf();
+    if (unit_header.unit_length == 0) return missing();
     const next_offset = unit_header.header_length + unit_header.unit_length;
 
     const version = try fbr.readInt(u16);
-    if (version < 2) return badDwarf();
+    if (version < 2) return bad();
 
     var addr_size: u8 = switch (unit_header.format) {
         .@"32" => 4,
@@ -1381,7 +1342,7 @@ pub fn getLineNumberInfo(
     const prog_start_offset = fbr.pos + prologue_length;
 
     const minimum_instruction_length = try fbr.readByte();
-    if (minimum_instruction_length == 0) return badDwarf();
+    if (minimum_instruction_length == 0) return bad();
 
     if (version >= 4) {
         // maximum_operations_per_instruction
@@ -1392,7 +1353,7 @@ pub fn getLineNumberInfo(
     const line_base = try fbr.readByteSigned();
 
     const line_range = try fbr.readByte();
-    if (line_range == 0) return badDwarf();
+    if (line_range == 0) return bad();
 
     const opcode_base = try fbr.readByte();
 
@@ -1433,7 +1394,7 @@ pub fn getLineNumberInfo(
         {
             var dir_ent_fmt_buf: [10]FileEntFmt = undefined;
             const directory_entry_format_count = try fbr.readByte();
-            if (directory_entry_format_count > dir_ent_fmt_buf.len) return badDwarf();
+            if (directory_entry_format_count > dir_ent_fmt_buf.len) return bad();
             for (dir_ent_fmt_buf[0..directory_entry_format_count]) |*ent_fmt| {
                 ent_fmt.* = .{
                     .content_type_code = try fbr.readUleb128(u8),
@@ -1461,7 +1422,7 @@ pub fn getLineNumberInfo(
                             DW.LNCT.size => e.size = try form_value.getUInt(u64),
                             DW.LNCT.MD5 => e.md5 = switch (form_value) {
                                 .data16 => |data16| data16.*,
-                                else => return badDwarf(),
+                                else => return bad(),
                             },
                             else => continue,
                         }
@@ -1473,7 +1434,7 @@ pub fn getLineNumberInfo(
 
         var file_ent_fmt_buf: [10]FileEntFmt = undefined;
         const file_name_entry_format_count = try fbr.readByte();
-        if (file_name_entry_format_count > file_ent_fmt_buf.len) return badDwarf();
+        if (file_name_entry_format_count > file_ent_fmt_buf.len) return bad();
         for (file_ent_fmt_buf[0..file_name_entry_format_count]) |*ent_fmt| {
             ent_fmt.* = .{
                 .content_type_code = try fbr.readUleb128(u8),
@@ -1501,7 +1462,7 @@ pub fn getLineNumberInfo(
                         DW.LNCT.size => e.size = try form_value.getUInt(u64),
                         DW.LNCT.MD5 => e.md5 = switch (form_value) {
                             .data16 => |data16| data16.*,
-                            else => return badDwarf(),
+                            else => return bad(),
                         },
                         else => continue,
                     }
@@ -1527,7 +1488,7 @@ pub fn getLineNumberInfo(
 
         if (opcode == DW.LNS.extended_op) {
             const op_size = try fbr.readUleb128(u64);
-            if (op_size < 1) return badDwarf();
+            if (op_size < 1) return bad();
             const sub_op = try fbr.readByte();
             switch (sub_op) {
                 DW.LNE.end_sequence => {
@@ -1600,14 +1561,14 @@ pub fn getLineNumberInfo(
                 },
                 DW.LNS.set_prologue_end => {},
                 else => {
-                    if (opcode - 1 >= standard_opcode_lengths.len) return badDwarf();
+                    if (opcode - 1 >= standard_opcode_lengths.len) return bad();
                     try fbr.seekForward(standard_opcode_lengths[opcode - 1]);
                 },
             }
         }
     }
 
-    return missingDwarf();
+    return missing();
 }
 
 fn getString(di: Dwarf, offset: u64) ![:0]const u8 {
@@ -1619,28 +1580,28 @@ fn getLineString(di: Dwarf, offset: u64) ![:0]const u8 {
 }
 
 fn readDebugAddr(di: Dwarf, compile_unit: CompileUnit, index: u64) !u64 {
-    const debug_addr = di.section(.debug_addr) orelse return badDwarf();
+    const debug_addr = di.section(.debug_addr) orelse return bad();
 
     // addr_base points to the first item after the header, however we
     // need to read the header to know the size of each item. Empirically,
     // it may disagree with is_64 on the compile unit.
     // The header is 8 or 12 bytes depending on is_64.
-    if (compile_unit.addr_base < 8) return badDwarf();
+    if (compile_unit.addr_base < 8) return bad();
 
     const version = readInt(u16, debug_addr[compile_unit.addr_base - 4 ..][0..2], di.endian);
-    if (version != 5) return badDwarf();
+    if (version != 5) return bad();
 
     const addr_size = debug_addr[compile_unit.addr_base - 2];
     const seg_size = debug_addr[compile_unit.addr_base - 1];
 
     const byte_offset = @as(usize, @intCast(compile_unit.addr_base + (addr_size + seg_size) * index));
-    if (byte_offset + addr_size > debug_addr.len) return badDwarf();
+    if (byte_offset + addr_size > debug_addr.len) return bad();
     return switch (addr_size) {
         1 => debug_addr[byte_offset],
         2 => readInt(u16, debug_addr[byte_offset..][0..2], di.endian),
         4 => readInt(u32, debug_addr[byte_offset..][0..4], di.endian),
         8 => readInt(u64, debug_addr[byte_offset..][0..8], di.endian),
-        else => badDwarf(),
+        else => bad(),
     };
 }
 
@@ -1650,7 +1611,7 @@ fn readDebugAddr(di: Dwarf, compile_unit: CompileUnit, index: u64) !u64 {
 /// of FDEs is built for binary searching during unwinding.
 pub fn scanAllUnwindInfo(di: *Dwarf, allocator: Allocator, base_address: usize) !void {
     if (di.section(.eh_frame_hdr)) |eh_frame_hdr| blk: {
-        var fbr: FixedBufferReader = .{ .buf = eh_frame_hdr, .endian = native_endian };
+        var fbr: DeprecatedFixedBufferReader = .{ .buf = eh_frame_hdr, .endian = native_endian };
 
         const version = try fbr.readByte();
         if (version != 1) break :blk;
@@ -1665,16 +1626,16 @@ pub fn scanAllUnwindInfo(di: *Dwarf, allocator: Allocator, base_address: usize)
         const eh_frame_ptr = cast(usize, try readEhPointer(&fbr, eh_frame_ptr_enc, @sizeOf(usize), .{
             .pc_rel_base = @intFromPtr(&eh_frame_hdr[fbr.pos]),
             .follow_indirect = true,
-        }) orelse return badDwarf()) orelse return badDwarf();
+        }) orelse return bad()) orelse return bad();
 
         const fde_count = cast(usize, try readEhPointer(&fbr, fde_count_enc, @sizeOf(usize), .{
             .pc_rel_base = @intFromPtr(&eh_frame_hdr[fbr.pos]),
             .follow_indirect = true,
-        }) orelse return badDwarf()) orelse return badDwarf();
+        }) orelse return bad()) orelse return bad();
 
         const entry_size = try ExceptionFrameHeader.entrySize(table_enc);
         const entries_len = fde_count * entry_size;
-        if (entries_len > eh_frame_hdr.len - fbr.pos) return badDwarf();
+        if (entries_len > eh_frame_hdr.len - fbr.pos) return bad();
 
         di.eh_frame_hdr = .{
             .eh_frame_ptr = eh_frame_ptr,
@@ -1690,7 +1651,7 @@ pub fn scanAllUnwindInfo(di: *Dwarf, allocator: Allocator, base_address: usize)
     const frame_sections = [2]Section.Id{ .eh_frame, .debug_frame };
     for (frame_sections) |frame_section| {
         if (di.section(frame_section)) |section_data| {
-            var fbr: FixedBufferReader = .{ .buf = section_data, .endian = di.endian };
+            var fbr: DeprecatedFixedBufferReader = .{ .buf = section_data, .endian = di.endian };
             while (fbr.pos < fbr.buf.len) {
                 const entry_header = try EntryHeader.read(&fbr, null, frame_section);
                 switch (entry_header.type) {
@@ -1708,7 +1669,7 @@ pub fn scanAllUnwindInfo(di: *Dwarf, allocator: Allocator, base_address: usize)
                         try di.cie_map.put(allocator, entry_header.length_offset, cie);
                     },
                     .fde => |cie_offset| {
-                        const cie = di.cie_map.get(cie_offset) orelse return badDwarf();
+                        const cie = di.cie_map.get(cie_offset) orelse return bad();
                         const fde = try FrameDescriptionEntry.parse(
                             entry_header.entry_bytes,
                             di.sectionVirtualOffset(frame_section, base_address).?,
@@ -1733,205 +1694,8 @@ pub fn scanAllUnwindInfo(di: *Dwarf, allocator: Allocator, base_address: usize)
     }
 }
 
-/// Unwind a stack frame using DWARF unwinding info, updating the register context.
-///
-/// If `.eh_frame_hdr` is available, it will be used to binary search for the FDE.
-/// Otherwise, a linear scan of `.eh_frame` and `.debug_frame` is done to find the FDE.
-///
-/// `explicit_fde_offset` is for cases where the FDE offset is known, such as when __unwind_info
-/// defers unwinding to DWARF. This is an offset into the `.eh_frame` section.
-pub fn unwindFrame(di: *const Dwarf, context: *UnwindContext, ma: *StackIterator.MemoryAccessor, explicit_fde_offset: ?usize) !usize {
-    if (!comptime abi.supportsUnwinding(builtin.target)) return error.UnsupportedCpuArchitecture;
-    if (context.pc == 0) return 0;
-
-    // Find the FDE and CIE
-    var cie: CommonInformationEntry = undefined;
-    var fde: FrameDescriptionEntry = undefined;
-
-    if (explicit_fde_offset) |fde_offset| {
-        const dwarf_section: Section.Id = .eh_frame;
-        const frame_section = di.section(dwarf_section) orelse return error.MissingFDE;
-        if (fde_offset >= frame_section.len) return error.MissingFDE;
-
-        var fbr: FixedBufferReader = .{
-            .buf = frame_section,
-            .pos = fde_offset,
-            .endian = di.endian,
-        };
-
-        const fde_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
-        if (fde_entry_header.type != .fde) return error.MissingFDE;
-
-        const cie_offset = fde_entry_header.type.fde;
-        try fbr.seekTo(cie_offset);
-
-        fbr.endian = native_endian;
-        const cie_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
-        if (cie_entry_header.type != .cie) return badDwarf();
-
-        cie = try CommonInformationEntry.parse(
-            cie_entry_header.entry_bytes,
-            0,
-            true,
-            cie_entry_header.format,
-            dwarf_section,
-            cie_entry_header.length_offset,
-            @sizeOf(usize),
-            native_endian,
-        );
-
-        fde = try FrameDescriptionEntry.parse(
-            fde_entry_header.entry_bytes,
-            0,
-            true,
-            cie,
-            @sizeOf(usize),
-            native_endian,
-        );
-    } else if (di.eh_frame_hdr) |header| {
-        const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
-        try header.findEntry(
-            ma,
-            eh_frame_len,
-            @intFromPtr(di.section(.eh_frame_hdr).?.ptr),
-            context.pc,
-            &cie,
-            &fde,
-        );
-    } else {
-        const index = std.sort.binarySearch(FrameDescriptionEntry, context.pc, di.fde_list.items, {}, struct {
-            pub fn compareFn(_: void, pc: usize, mid_item: FrameDescriptionEntry) std.math.Order {
-                if (pc < mid_item.pc_begin) return .lt;
-
-                const range_end = mid_item.pc_begin + mid_item.pc_range;
-                if (pc < range_end) return .eq;
-
-                return .gt;
-            }
-        }.compareFn);
-
-        fde = if (index) |i| di.fde_list.items[i] else return error.MissingFDE;
-        cie = di.cie_map.get(fde.cie_length_offset) orelse return error.MissingCIE;
-    }
-
-    var expression_context: expression.Context = .{
-        .format = cie.format,
-        .memory_accessor = ma,
-        .compile_unit = di.findCompileUnit(fde.pc_begin) catch null,
-        .thread_context = context.thread_context,
-        .reg_context = context.reg_context,
-        .cfa = context.cfa,
-    };
-
-    context.vm.reset();
-    context.reg_context.eh_frame = cie.version != 4;
-    context.reg_context.is_macho = di.is_macho;
-
-    const row = try context.vm.runToNative(context.allocator, context.pc, cie, fde);
-    context.cfa = switch (row.cfa.rule) {
-        .val_offset => |offset| blk: {
-            const register = row.cfa.register orelse return error.InvalidCFARule;
-            const value = readInt(usize, (try abi.regBytes(context.thread_context, register, context.reg_context))[0..@sizeOf(usize)], native_endian);
-            break :blk try call_frame.applyOffset(value, offset);
-        },
-        .expression => |expr| blk: {
-            context.stack_machine.reset();
-            const value = try context.stack_machine.run(
-                expr,
-                context.allocator,
-                expression_context,
-                context.cfa,
-            );
-
-            if (value) |v| {
-                if (v != .generic) return error.InvalidExpressionValue;
-                break :blk v.generic;
-            } else return error.NoExpressionValue;
-        },
-        else => return error.InvalidCFARule,
-    };
-
-    if (ma.load(usize, context.cfa.?) == null) return error.InvalidCFA;
-    expression_context.cfa = context.cfa;
-
-    // Buffering the modifications is done because copying the thread context is not portable,
-    // some implementations (ie. darwin) use internal pointers to the mcontext.
-    var arena = std.heap.ArenaAllocator.init(context.allocator);
-    defer arena.deinit();
-    const update_allocator = arena.allocator();
-
-    const RegisterUpdate = struct {
-        // Backed by thread_context
-        dest: []u8,
-        // Backed by arena
-        src: []const u8,
-        prev: ?*@This(),
-    };
-
-    var update_tail: ?*RegisterUpdate = null;
-    var has_return_address = true;
-    for (context.vm.rowColumns(row)) |column| {
-        if (column.register) |register| {
-            if (register == cie.return_address_register) {
-                has_return_address = column.rule != .undefined;
-            }
-
-            const dest = try abi.regBytes(context.thread_context, register, context.reg_context);
-            const src = try update_allocator.alloc(u8, dest.len);
-
-            const prev = update_tail;
-            update_tail = try update_allocator.create(RegisterUpdate);
-            update_tail.?.* = .{
-                .dest = dest,
-                .src = src,
-                .prev = prev,
-            };
-
-            try column.resolveValue(
-                context,
-                expression_context,
-                ma,
-                src,
-            );
-        }
-    }
-
-    // On all implemented architectures, the CFA is defined as being the previous frame's SP
-    (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(context.reg_context), context.reg_context)).* = context.cfa.?;
-
-    while (update_tail) |tail| {
-        @memcpy(tail.dest, tail.src);
-        update_tail = tail.prev;
-    }
-
-    if (has_return_address) {
-        context.pc = abi.stripInstructionPtrAuthCode(readInt(usize, (try abi.regBytes(
-            context.thread_context,
-            cie.return_address_register,
-            context.reg_context,
-        ))[0..@sizeOf(usize)], native_endian));
-    } else {
-        context.pc = 0;
-    }
-
-    (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), context.reg_context)).* = context.pc;
-
-    // The call instruction will have pushed the address of the instruction that follows the call as the return address.
-    // This next instruction may be past the end of the function if the caller was `noreturn` (ie. the last instruction in
-    // the function was the call). If we were to look up an FDE entry using the return address directly, it could end up
-    // either not finding an FDE at all, or using the next FDE in the program, producing incorrect results. To prevent this,
-    // we subtract one so that the next lookup is guaranteed to land inside the
-    //
-    // The exception to this rule is signal frames, where we return execution would be returned to the instruction
-    // that triggered the handler.
-    const return_address = context.pc;
-    if (context.pc > 0 and !cie.isSignalFrame()) context.pc -= 1;
-
-    return return_address;
-}
-
 fn parseFormValue(
-    fbr: *FixedBufferReader,
+    fbr: *DeprecatedFixedBufferReader,
     form_id: u64,
     format: Format,
     implicit_const: ?i64,
@@ -1990,12 +1754,12 @@ fn parseFormValue(
         FORM.strx => .{ .strx = try fbr.readUleb128(usize) },
         FORM.line_strp => .{ .line_strp = try fbr.readAddress(format) },
         FORM.indirect => parseFormValue(fbr, try fbr.readUleb128(u64), format, implicit_const),
-        FORM.implicit_const => .{ .sdata = implicit_const orelse return badDwarf() },
+        FORM.implicit_const => .{ .sdata = implicit_const orelse return bad() },
         FORM.loclistx => .{ .loclistx = try fbr.readUleb128(u64) },
         FORM.rnglistx => .{ .rnglistx = try fbr.readUleb128(u64) },
         else => {
             //debug.print("unrecognized form id: {x}\n", .{form_id});
-            return badDwarf();
+            return bad();
         },
     };
 }
@@ -2084,27 +1848,27 @@ const LineNumberProgram = struct {
         self: *LineNumberProgram,
         allocator: Allocator,
         file_entries: []const FileEntry,
-    ) !?std.debug.LineInfo {
+    ) !?std.debug.SourceLocation {
         if (self.prev_valid and
             self.target_address >= self.prev_address and
             self.target_address < self.address)
         {
             const file_index = if (self.version >= 5) self.prev_file else i: {
-                if (self.prev_file == 0) return missingDwarf();
+                if (self.prev_file == 0) return missing();
                 break :i self.prev_file - 1;
             };
 
-            if (file_index >= file_entries.len) return badDwarf();
+            if (file_index >= file_entries.len) return bad();
             const file_entry = &file_entries[file_index];
 
-            if (file_entry.dir_index >= self.include_dirs.len) return badDwarf();
+            if (file_entry.dir_index >= self.include_dirs.len) return bad();
             const dir_name = self.include_dirs[file_entry.dir_index].path;
 
             const file_name = try std.fs.path.join(allocator, &[_][]const u8{
                 dir_name, file_entry.path,
             });
 
-            return std.debug.LineInfo{
+            return std.debug.SourceLocation{
                 .line = if (self.prev_line >= 0) @as(u64, @intCast(self.prev_line)) else 0,
                 .column = self.prev_column,
                 .file_name = file_name,
@@ -2128,14 +1892,14 @@ const UnitHeader = struct {
     header_length: u4,
     unit_length: u64,
 };
-fn readUnitHeader(fbr: *FixedBufferReader, opt_ma: ?*StackIterator.MemoryAccessor) !UnitHeader {
+fn readUnitHeader(fbr: *DeprecatedFixedBufferReader, opt_ma: ?*MemoryAccessor) !UnitHeader {
     return switch (try if (opt_ma) |ma| fbr.readIntChecked(u32, ma) else fbr.readInt(u32)) {
         0...0xfffffff0 - 1 => |unit_length| .{
             .format = .@"32",
             .header_length = 4,
             .unit_length = unit_length,
         },
-        0xfffffff0...0xffffffff - 1 => badDwarf(),
+        0xfffffff0...0xffffffff - 1 => bad(),
         0xffffffff => .{
             .format = .@"64",
             .header_length = 12,
@@ -2145,7 +1909,7 @@ fn readUnitHeader(fbr: *FixedBufferReader, opt_ma: ?*StackIterator.MemoryAccesso
 }
 
 /// Returns the DWARF register number for an x86_64 register number found in compact unwind info
-fn compactUnwindToDwarfRegNumber(unwind_reg_number: u3) !u8 {
+pub fn compactUnwindToDwarfRegNumber(unwind_reg_number: u3) !u8 {
     return switch (unwind_reg_number) {
         1 => 3, // RBX
         2 => 12, // R12
@@ -2159,473 +1923,25 @@ fn compactUnwindToDwarfRegNumber(unwind_reg_number: u3) !u8 {
 
 /// This function is to make it handy to comment out the return and make it
 /// into a crash when working on this file.
-fn badDwarf() error{InvalidDebugInfo} {
-    //if (true) @panic("badDwarf"); // can be handy to uncomment when working on this file
+pub fn bad() error{InvalidDebugInfo} {
+    //if (true) @panic("bad dwarf"); // can be handy to uncomment when working on this file
     return error.InvalidDebugInfo;
 }
 
-fn missingDwarf() error{MissingDebugInfo} {
-    //if (true) @panic("missingDwarf"); // can be handy to uncomment when working on this file
+fn missing() error{MissingDebugInfo} {
+    //if (true) @panic("missing dwarf"); // can be handy to uncomment when working on this file
     return error.MissingDebugInfo;
 }
 
 fn getStringGeneric(opt_str: ?[]const u8, offset: u64) ![:0]const u8 {
-    const str = opt_str orelse return badDwarf();
-    if (offset > str.len) return badDwarf();
-    const casted_offset = cast(usize, offset) orelse return badDwarf();
+    const str = opt_str orelse return bad();
+    if (offset > str.len) return bad();
+    const casted_offset = cast(usize, offset) orelse return bad();
     // Valid strings always have a terminating zero byte
-    const last = std.mem.indexOfScalarPos(u8, str, casted_offset, 0) orelse return badDwarf();
+    const last = std.mem.indexOfScalarPos(u8, str, casted_offset, 0) orelse return bad();
     return str[casted_offset..last :0];
 }
 
-// Reading debug info needs to be fast, even when compiled in debug mode,
-// so avoid using a `std.io.FixedBufferStream` which is too slow.
-pub const FixedBufferReader = struct {
-    buf: []const u8,
-    pos: usize = 0,
-    endian: std.builtin.Endian,
-
-    pub const Error = error{ EndOfBuffer, Overflow, InvalidBuffer };
-
-    fn seekTo(fbr: *FixedBufferReader, pos: u64) Error!void {
-        if (pos > fbr.buf.len) return error.EndOfBuffer;
-        fbr.pos = @intCast(pos);
-    }
-
-    fn seekForward(fbr: *FixedBufferReader, amount: u64) Error!void {
-        if (fbr.buf.len - fbr.pos < amount) return error.EndOfBuffer;
-        fbr.pos += @intCast(amount);
-    }
-
-    pub inline fn readByte(fbr: *FixedBufferReader) Error!u8 {
-        if (fbr.pos >= fbr.buf.len) return error.EndOfBuffer;
-        defer fbr.pos += 1;
-        return fbr.buf[fbr.pos];
-    }
-
-    fn readByteSigned(fbr: *FixedBufferReader) Error!i8 {
-        return @bitCast(try fbr.readByte());
-    }
-
-    fn readInt(fbr: *FixedBufferReader, comptime T: type) Error!T {
-        const size = @divExact(@typeInfo(T).Int.bits, 8);
-        if (fbr.buf.len - fbr.pos < size) return error.EndOfBuffer;
-        defer fbr.pos += size;
-        return std.mem.readInt(T, fbr.buf[fbr.pos..][0..size], fbr.endian);
-    }
-
-    fn readIntChecked(
-        fbr: *FixedBufferReader,
-        comptime T: type,
-        ma: *std.debug.StackIterator.MemoryAccessor,
-    ) Error!T {
-        if (ma.load(T, @intFromPtr(fbr.buf[fbr.pos..].ptr)) == null)
-            return error.InvalidBuffer;
-
-        return fbr.readInt(T);
-    }
-
-    fn readUleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
-        return std.leb.readUleb128(T, fbr);
-    }
-
-    fn readIleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
-        return std.leb.readIleb128(T, fbr);
-    }
-
-    fn readAddress(fbr: *FixedBufferReader, format: Format) Error!u64 {
-        return switch (format) {
-            .@"32" => try fbr.readInt(u32),
-            .@"64" => try fbr.readInt(u64),
-        };
-    }
-
-    fn readAddressChecked(
-        fbr: *FixedBufferReader,
-        format: Format,
-        ma: *std.debug.StackIterator.MemoryAccessor,
-    ) Error!u64 {
-        return switch (format) {
-            .@"32" => try fbr.readIntChecked(u32, ma),
-            .@"64" => try fbr.readIntChecked(u64, ma),
-        };
-    }
-
-    fn readBytes(fbr: *FixedBufferReader, len: usize) Error![]const u8 {
-        if (fbr.buf.len - fbr.pos < len) return error.EndOfBuffer;
-        defer fbr.pos += len;
-        return fbr.buf[fbr.pos..][0..len];
-    }
-
-    fn readBytesTo(fbr: *FixedBufferReader, comptime sentinel: u8) Error![:sentinel]const u8 {
-        const end = @call(.always_inline, std.mem.indexOfScalarPos, .{
-            u8,
-            fbr.buf,
-            fbr.pos,
-            sentinel,
-        }) orelse return error.EndOfBuffer;
-        defer fbr.pos = end + 1;
-        return fbr.buf[fbr.pos..end :sentinel];
-    }
-};
-
-/// Unwind a frame using MachO compact unwind info (from __unwind_info).
-/// If the compact encoding can't encode a way to unwind a frame, it will
-/// defer unwinding to DWARF, in which case `.eh_frame` will be used if available.
-pub fn unwindFrameMachO(
-    context: *UnwindContext,
-    ma: *StackIterator.MemoryAccessor,
-    unwind_info: []const u8,
-    eh_frame: ?[]const u8,
-    module_base_address: usize,
-) !usize {
-    const macho = std.macho;
-
-    const header = std.mem.bytesAsValue(
-        macho.unwind_info_section_header,
-        unwind_info[0..@sizeOf(macho.unwind_info_section_header)],
-    );
-    const indices = std.mem.bytesAsSlice(
-        macho.unwind_info_section_header_index_entry,
-        unwind_info[header.indexSectionOffset..][0 .. header.indexCount * @sizeOf(macho.unwind_info_section_header_index_entry)],
-    );
-    if (indices.len == 0) return error.MissingUnwindInfo;
-
-    const mapped_pc = context.pc - module_base_address;
-    const second_level_index = blk: {
-        var left: usize = 0;
-        var len: usize = indices.len;
-
-        while (len > 1) {
-            const mid = left + len / 2;
-            const offset = indices[mid].functionOffset;
-            if (mapped_pc < offset) {
-                len /= 2;
-            } else {
-                left = mid;
-                if (mapped_pc == offset) break;
-                len -= len / 2;
-            }
-        }
-
-        // Last index is a sentinel containing the highest address as its functionOffset
-        if (indices[left].secondLevelPagesSectionOffset == 0) return error.MissingUnwindInfo;
-        break :blk &indices[left];
-    };
-
-    const common_encodings = std.mem.bytesAsSlice(
-        macho.compact_unwind_encoding_t,
-        unwind_info[header.commonEncodingsArraySectionOffset..][0 .. header.commonEncodingsArrayCount * @sizeOf(macho.compact_unwind_encoding_t)],
-    );
-
-    const start_offset = second_level_index.secondLevelPagesSectionOffset;
-    const kind = std.mem.bytesAsValue(
-        macho.UNWIND_SECOND_LEVEL,
-        unwind_info[start_offset..][0..@sizeOf(macho.UNWIND_SECOND_LEVEL)],
-    );
-
-    const entry: struct {
-        function_offset: usize,
-        raw_encoding: u32,
-    } = switch (kind.*) {
-        .REGULAR => blk: {
-            const page_header = std.mem.bytesAsValue(
-                macho.unwind_info_regular_second_level_page_header,
-                unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_regular_second_level_page_header)],
-            );
-
-            const entries = std.mem.bytesAsSlice(
-                macho.unwind_info_regular_second_level_entry,
-                unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.unwind_info_regular_second_level_entry)],
-            );
-            if (entries.len == 0) return error.InvalidUnwindInfo;
-
-            var left: usize = 0;
-            var len: usize = entries.len;
-            while (len > 1) {
-                const mid = left + len / 2;
-                const offset = entries[mid].functionOffset;
-                if (mapped_pc < offset) {
-                    len /= 2;
-                } else {
-                    left = mid;
-                    if (mapped_pc == offset) break;
-                    len -= len / 2;
-                }
-            }
-
-            break :blk .{
-                .function_offset = entries[left].functionOffset,
-                .raw_encoding = entries[left].encoding,
-            };
-        },
-        .COMPRESSED => blk: {
-            const page_header = std.mem.bytesAsValue(
-                macho.unwind_info_compressed_second_level_page_header,
-                unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_compressed_second_level_page_header)],
-            );
-
-            const entries = std.mem.bytesAsSlice(
-                macho.UnwindInfoCompressedEntry,
-                unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.UnwindInfoCompressedEntry)],
-            );
-            if (entries.len == 0) return error.InvalidUnwindInfo;
-
-            var left: usize = 0;
-            var len: usize = entries.len;
-            while (len > 1) {
-                const mid = left + len / 2;
-                const offset = second_level_index.functionOffset + entries[mid].funcOffset;
-                if (mapped_pc < offset) {
-                    len /= 2;
-                } else {
-                    left = mid;
-                    if (mapped_pc == offset) break;
-                    len -= len / 2;
-                }
-            }
-
-            const entry = entries[left];
-            const function_offset = second_level_index.functionOffset + entry.funcOffset;
-            if (entry.encodingIndex < header.commonEncodingsArrayCount) {
-                if (entry.encodingIndex >= common_encodings.len) return error.InvalidUnwindInfo;
-                break :blk .{
-                    .function_offset = function_offset,
-                    .raw_encoding = common_encodings[entry.encodingIndex],
-                };
-            } else {
-                const local_index = try std.math.sub(
-                    u8,
-                    entry.encodingIndex,
-                    cast(u8, header.commonEncodingsArrayCount) orelse return error.InvalidUnwindInfo,
-                );
-                const local_encodings = std.mem.bytesAsSlice(
-                    macho.compact_unwind_encoding_t,
-                    unwind_info[start_offset + page_header.encodingsPageOffset ..][0 .. page_header.encodingsCount * @sizeOf(macho.compact_unwind_encoding_t)],
-                );
-                if (local_index >= local_encodings.len) return error.InvalidUnwindInfo;
-                break :blk .{
-                    .function_offset = function_offset,
-                    .raw_encoding = local_encodings[local_index],
-                };
-            }
-        },
-        else => return error.InvalidUnwindInfo,
-    };
-
-    if (entry.raw_encoding == 0) return error.NoUnwindInfo;
-    const reg_context = abi.RegisterContext{
-        .eh_frame = false,
-        .is_macho = true,
-    };
-
-    const encoding: macho.CompactUnwindEncoding = @bitCast(entry.raw_encoding);
-    const new_ip = switch (builtin.cpu.arch) {
-        .x86_64 => switch (encoding.mode.x86_64) {
-            .OLD => return error.UnimplementedUnwindEncoding,
-            .RBP_FRAME => blk: {
-                const regs: [5]u3 = .{
-                    encoding.value.x86_64.frame.reg0,
-                    encoding.value.x86_64.frame.reg1,
-                    encoding.value.x86_64.frame.reg2,
-                    encoding.value.x86_64.frame.reg3,
-                    encoding.value.x86_64.frame.reg4,
-                };
-
-                const frame_offset = encoding.value.x86_64.frame.frame_offset * @sizeOf(usize);
-                var max_reg: usize = 0;
-                inline for (regs, 0..) |reg, i| {
-                    if (reg > 0) max_reg = i;
-                }
-
-                const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
-                const new_sp = fp + 2 * @sizeOf(usize);
-
-                // Verify the stack range we're about to read register values from
-                if (ma.load(usize, new_sp) == null or ma.load(usize, fp - frame_offset + max_reg * @sizeOf(usize)) == null) return error.InvalidUnwindInfo;
-
-                const ip_ptr = fp + @sizeOf(usize);
-                const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
-                const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
-
-                (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
-                (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
-                (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
-
-                for (regs, 0..) |reg, i| {
-                    if (reg == 0) continue;
-                    const addr = fp - frame_offset + i * @sizeOf(usize);
-                    const reg_number = try compactUnwindToDwarfRegNumber(reg);
-                    (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(addr)).*;
-                }
-
-                break :blk new_ip;
-            },
-            .STACK_IMMD,
-            .STACK_IND,
-            => blk: {
-                const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
-                const stack_size = if (encoding.mode.x86_64 == .STACK_IMMD)
-                    @as(usize, encoding.value.x86_64.frameless.stack.direct.stack_size) * @sizeOf(usize)
-                else stack_size: {
-                    // In .STACK_IND, the stack size is inferred from the subq instruction at the beginning of the function.
-                    const sub_offset_addr =
-                        module_base_address +
-                        entry.function_offset +
-                        encoding.value.x86_64.frameless.stack.indirect.sub_offset;
-                    if (ma.load(usize, sub_offset_addr) == null) return error.InvalidUnwindInfo;
-
-                    // `sub_offset_addr` points to the offset of the literal within the instruction
-                    const sub_operand = @as(*align(1) const u32, @ptrFromInt(sub_offset_addr)).*;
-                    break :stack_size sub_operand + @sizeOf(usize) * @as(usize, encoding.value.x86_64.frameless.stack.indirect.stack_adjust);
-                };
-
-                // Decode the Lehmer-coded sequence of registers.
-                // For a description of the encoding see lib/libc/include/any-macos.13-any/mach-o/compact_unwind_encoding.h
-
-                // Decode the variable-based permutation number into its digits. Each digit represents
-                // an index into the list of register numbers that weren't yet used in the sequence at
-                // the time the digit was added.
-                const reg_count = encoding.value.x86_64.frameless.stack_reg_count;
-                const ip_ptr = if (reg_count > 0) reg_blk: {
-                    var digits: [6]u3 = undefined;
-                    var accumulator: usize = encoding.value.x86_64.frameless.stack_reg_permutation;
-                    var base: usize = 2;
-                    for (0..reg_count) |i| {
-                        const div = accumulator / base;
-                        digits[digits.len - 1 - i] = @intCast(accumulator - base * div);
-                        accumulator = div;
-                        base += 1;
-                    }
-
-                    const reg_numbers = [_]u3{ 1, 2, 3, 4, 5, 6 };
-                    var registers: [reg_numbers.len]u3 = undefined;
-                    var used_indices = [_]bool{false} ** reg_numbers.len;
-                    for (digits[digits.len - reg_count ..], 0..) |target_unused_index, i| {
-                        var unused_count: u8 = 0;
-                        const unused_index = for (used_indices, 0..) |used, index| {
-                            if (!used) {
-                                if (target_unused_index == unused_count) break index;
-                                unused_count += 1;
-                            }
-                        } else unreachable;
-
-                        registers[i] = reg_numbers[unused_index];
-                        used_indices[unused_index] = true;
-                    }
-
-                    var reg_addr = sp + stack_size - @sizeOf(usize) * @as(usize, reg_count + 1);
-                    if (ma.load(usize, reg_addr) == null) return error.InvalidUnwindInfo;
-                    for (0..reg_count) |i| {
-                        const reg_number = try compactUnwindToDwarfRegNumber(registers[i]);
-                        (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
-                        reg_addr += @sizeOf(usize);
-                    }
-
-                    break :reg_blk reg_addr;
-                } else sp + stack_size - @sizeOf(usize);
-
-                const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
-                const new_sp = ip_ptr + @sizeOf(usize);
-                if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
-
-                (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
-                (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
-
-                break :blk new_ip;
-            },
-            .DWARF => {
-                return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
-            },
-        },
-        .aarch64 => switch (encoding.mode.arm64) {
-            .OLD => return error.UnimplementedUnwindEncoding,
-            .FRAMELESS => blk: {
-                const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
-                const new_sp = sp + encoding.value.arm64.frameless.stack_size * 16;
-                const new_ip = (try abi.regValueNative(usize, context.thread_context, 30, reg_context)).*;
-                if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
-                (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
-                break :blk new_ip;
-            },
-            .DWARF => {
-                return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
-            },
-            .FRAME => blk: {
-                const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
-                const new_sp = fp + 16;
-                const ip_ptr = fp + @sizeOf(usize);
-
-                const num_restored_pairs: usize =
-                    @popCount(@as(u5, @bitCast(encoding.value.arm64.frame.x_reg_pairs))) +
-                    @popCount(@as(u4, @bitCast(encoding.value.arm64.frame.d_reg_pairs)));
-                const min_reg_addr = fp - num_restored_pairs * 2 * @sizeOf(usize);
-
-                if (ma.load(usize, new_sp) == null or ma.load(usize, min_reg_addr) == null) return error.InvalidUnwindInfo;
-
-                var reg_addr = fp - @sizeOf(usize);
-                inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.x_reg_pairs)).Struct.fields, 0..) |field, i| {
-                    if (@field(encoding.value.arm64.frame.x_reg_pairs, field.name) != 0) {
-                        (try abi.regValueNative(usize, context.thread_context, 19 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
-                        reg_addr += @sizeOf(usize);
-                        (try abi.regValueNative(usize, context.thread_context, 20 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
-                        reg_addr += @sizeOf(usize);
-                    }
-                }
-
-                inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.d_reg_pairs)).Struct.fields, 0..) |field, i| {
-                    if (@field(encoding.value.arm64.frame.d_reg_pairs, field.name) != 0) {
-                        // Only the lower half of the 128-bit V registers are restored during unwinding
-                        @memcpy(
-                            try abi.regBytes(context.thread_context, 64 + 8 + i, context.reg_context),
-                            std.mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
-                        );
-                        reg_addr += @sizeOf(usize);
-                        @memcpy(
-                            try abi.regBytes(context.thread_context, 64 + 9 + i, context.reg_context),
-                            std.mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
-                        );
-                        reg_addr += @sizeOf(usize);
-                    }
-                }
-
-                const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
-                const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
-
-                (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
-                (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
-
-                break :blk new_ip;
-            },
-        },
-        else => return error.UnimplementedArch,
-    };
-
-    context.pc = abi.stripInstructionPtrAuthCode(new_ip);
-    if (context.pc > 0) context.pc -= 1;
-    return new_ip;
-}
-
-fn unwindFrameMachODwarf(
-    context: *UnwindContext,
-    ma: *std.debug.StackIterator.MemoryAccessor,
-    eh_frame: []const u8,
-    fde_offset: usize,
-) !usize {
-    var di = Dwarf{
-        .endian = native_endian,
-        .is_macho = true,
-    };
-    defer di.deinit(context.allocator);
-
-    di.sections[@intFromEnum(Section.Id.eh_frame)] = .{
-        .data = eh_frame,
-        .owned = false,
-    };
-
-    return di.unwindFrame(context, ma, fde_offset);
-}
-
 const EhPointerContext = struct {
     // The address of the pointer field itself
     pc_rel_base: u64,
@@ -2641,7 +1957,7 @@ const EhPointerContext = struct {
     text_rel_base: ?u64 = null,
     function_rel_base: ?u64 = null,
 };
-fn readEhPointer(fbr: *FixedBufferReader, enc: u8, addr_size_bytes: u8, ctx: EhPointerContext) !?u64 {
+fn readEhPointer(fbr: *DeprecatedFixedBufferReader, enc: u8, addr_size_bytes: u8, ctx: EhPointerContext) !?u64 {
     if (enc == EH.PE.omit) return null;
 
     const value: union(enum) {
@@ -2664,7 +1980,7 @@ fn readEhPointer(fbr: *FixedBufferReader, enc: u8, addr_size_bytes: u8, ctx: EhP
         EH.PE.sdata2 => .{ .signed = try fbr.readInt(i16) },
         EH.PE.sdata4 => .{ .signed = try fbr.readInt(i32) },
         EH.PE.sdata8 => .{ .signed = try fbr.readInt(i64) },
-        else => return badDwarf(),
+        else => return bad(),
     };
 
     const base = switch (enc & EH.PE.rel_mask) {
diff --git a/lib/std/debug/Dwarf/abi.zig b/lib/std/debug/Dwarf/abi.zig
index 1a47625ae7..b2c4cb9536 100644
--- a/lib/std/debug/Dwarf/abi.zig
+++ b/lib/std/debug/Dwarf/abi.zig
@@ -1,44 +1,50 @@
 const builtin = @import("builtin");
+
 const std = @import("../../std.zig");
 const mem = std.mem;
-const native_os = builtin.os.tag;
 const posix = std.posix;
+const Arch = std.Target.Cpu.Arch;
 
+/// Tells whether unwinding for this target is supported by the Dwarf standard.
+///
+/// See also `std.debug.SelfInfo.supportsUnwinding` which tells whether the Zig
+/// standard library has a working implementation of unwinding for this target.
 pub fn supportsUnwinding(target: std.Target) bool {
     return switch (target.cpu.arch) {
-        .x86 => switch (target.os.tag) {
-            .linux, .netbsd, .solaris, .illumos => true,
-            else => false,
-        },
-        .x86_64 => switch (target.os.tag) {
-            .linux, .netbsd, .freebsd, .openbsd, .macos, .ios, .solaris, .illumos => true,
-            else => false,
-        },
-        .arm => switch (target.os.tag) {
-            .linux => true,
-            else => false,
-        },
-        .aarch64 => switch (target.os.tag) {
-            .linux, .netbsd, .freebsd, .macos, .ios => true,
-            else => false,
-        },
-        else => false,
+        .amdgcn,
+        .nvptx,
+        .nvptx64,
+        .spirv,
+        .spirv32,
+        .spirv64,
+        .spu_2,
+        => false,
+
+        // Enabling this causes relocation errors such as:
+        // error: invalid relocation type R_RISCV_SUB32 at offset 0x20
+        .riscv64, .riscv32 => false,
+
+        // Conservative guess. Feel free to update this logic with any targets
+        // that are known to not support Dwarf unwinding.
+        else => true,
     };
 }
 
-pub fn ipRegNum() u8 {
-    return switch (builtin.cpu.arch) {
+/// Returns `null` for CPU architectures without an instruction pointer register.
+pub fn ipRegNum(arch: Arch) ?u8 {
+    return switch (arch) {
         .x86 => 8,
         .x86_64 => 16,
         .arm => 15,
         .aarch64 => 32,
-        else => unreachable,
+        else => null,
     };
 }
 
-pub fn fpRegNum(reg_context: RegisterContext) u8 {
-    return switch (builtin.cpu.arch) {
-        // GCC on OS X historically did the opposite of ELF for these registers (only in .eh_frame), and that is now the convention for MachO
+pub fn fpRegNum(arch: Arch, reg_context: RegisterContext) u8 {
+    return switch (arch) {
+        // GCC on OS X historically did the opposite of ELF for these registers
+        // (only in .eh_frame), and that is now the convention for MachO
         .x86 => if (reg_context.eh_frame and reg_context.is_macho) 4 else 5,
         .x86_64 => 6,
         .arm => 11,
@@ -47,8 +53,8 @@ pub fn fpRegNum(reg_context: RegisterContext) u8 {
     };
 }
 
-pub fn spRegNum(reg_context: RegisterContext) u8 {
-    return switch (builtin.cpu.arch) {
+pub fn spRegNum(arch: Arch, reg_context: RegisterContext) u8 {
+    return switch (arch) {
         .x86 => if (reg_context.eh_frame and reg_context.is_macho) 5 else 4,
         .x86_64 => 7,
         .arm => 13,
@@ -57,33 +63,12 @@ pub fn spRegNum(reg_context: RegisterContext) u8 {
     };
 }
 
-/// Some platforms use pointer authentication - the upper bits of instruction pointers contain a signature.
-/// This function clears these signature bits to make the pointer usable.
-pub inline fn stripInstructionPtrAuthCode(ptr: usize) usize {
-    if (builtin.cpu.arch == .aarch64) {
-        // `hint 0x07` maps to `xpaclri` (or `nop` if the hardware doesn't support it)
-        // The save / restore is because `xpaclri` operates on x30 (LR)
-        return asm (
-            \\mov x16, x30
-            \\mov x30, x15
-            \\hint 0x07
-            \\mov x15, x30
-            \\mov x30, x16
-            : [ret] "={x15}" (-> usize),
-            : [ptr] "{x15}" (ptr),
-            : "x16"
-        );
-    }
-
-    return ptr;
-}
-
 pub const RegisterContext = struct {
     eh_frame: bool,
     is_macho: bool,
 };
 
-pub const AbiError = error{
+pub const RegBytesError = error{
     InvalidRegister,
     UnimplementedArch,
     UnimplementedOs,
@@ -91,55 +76,21 @@ pub const AbiError = error{
     ThreadContextNotSupported,
 };
 
-fn RegValueReturnType(comptime ContextPtrType: type, comptime T: type) type {
-    const reg_bytes_type = comptime RegBytesReturnType(ContextPtrType);
-    const info = @typeInfo(reg_bytes_type).Pointer;
-    return @Type(.{
-        .Pointer = .{
-            .size = .One,
-            .is_const = info.is_const,
-            .is_volatile = info.is_volatile,
-            .is_allowzero = info.is_allowzero,
-            .alignment = info.alignment,
-            .address_space = info.address_space,
-            .child = T,
-            .sentinel = null,
-        },
-    });
-}
-
-/// Returns a pointer to a register stored in a ThreadContext, preserving the pointer attributes of the context.
-pub fn regValueNative(
-    comptime T: type,
-    thread_context_ptr: anytype,
-    reg_number: u8,
-    reg_context: ?RegisterContext,
-) !RegValueReturnType(@TypeOf(thread_context_ptr), T) {
-    const reg_bytes = try regBytes(thread_context_ptr, reg_number, reg_context);
-    if (@sizeOf(T) != reg_bytes.len) return error.IncompatibleRegisterSize;
-    return mem.bytesAsValue(T, reg_bytes[0..@sizeOf(T)]);
-}
-
-fn RegBytesReturnType(comptime ContextPtrType: type) type {
-    const info = @typeInfo(ContextPtrType);
-    if (info != .Pointer or info.Pointer.child != std.debug.ThreadContext) {
-        @compileError("Expected a pointer to std.debug.ThreadContext, got " ++ @typeName(@TypeOf(ContextPtrType)));
-    }
-
-    return if (info.Pointer.is_const) return []const u8 else []u8;
-}
-
 /// Returns a slice containing the backing storage for `reg_number`.
 ///
+/// This function assumes the Dwarf information corresponds not necessarily to
+/// the current executable, but at least with a matching CPU architecture and
+/// OS. It is planned to lift this limitation with a future enhancement.
+///
 /// `reg_context` describes in what context the register number is used, as it can have different
 /// meanings depending on the DWARF container. It is only required when getting the stack or
 /// frame pointer register on some architectures.
 pub fn regBytes(
-    thread_context_ptr: anytype,
+    thread_context_ptr: *std.debug.ThreadContext,
     reg_number: u8,
     reg_context: ?RegisterContext,
-) AbiError!RegBytesReturnType(@TypeOf(thread_context_ptr)) {
-    if (native_os == .windows) {
+) RegBytesError![]u8 {
+    if (builtin.os.tag == .windows) {
         return switch (builtin.cpu.arch) {
             .x86 => switch (reg_number) {
                 0 => mem.asBytes(&thread_context_ptr.Eax),
@@ -194,7 +145,7 @@ pub fn regBytes(
 
     const ucontext_ptr = thread_context_ptr;
     return switch (builtin.cpu.arch) {
-        .x86 => switch (native_os) {
+        .x86 => switch (builtin.os.tag) {
             .linux, .netbsd, .solaris, .illumos => switch (reg_number) {
                 0 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.EAX]),
                 1 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.ECX]),
@@ -229,7 +180,7 @@ pub fn regBytes(
             },
             else => error.UnimplementedOs,
         },
-        .x86_64 => switch (native_os) {
+        .x86_64 => switch (builtin.os.tag) {
             .linux, .solaris, .illumos => switch (reg_number) {
                 0 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.RAX]),
                 1 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.RDX]),
@@ -248,7 +199,7 @@ pub fn regBytes(
                 14 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.R14]),
                 15 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.R15]),
                 16 => mem.asBytes(&ucontext_ptr.mcontext.gregs[posix.REG.RIP]),
-                17...32 => |i| if (native_os.isSolarish())
+                17...32 => |i| if (builtin.os.tag.isSolarish())
                     mem.asBytes(&ucontext_ptr.mcontext.fpregs.chip_state.xmm[i - 17])
                 else
                     mem.asBytes(&ucontext_ptr.mcontext.fpregs.xmm[i - 17]),
@@ -318,7 +269,7 @@ pub fn regBytes(
             },
             else => error.UnimplementedOs,
         },
-        .arm => switch (native_os) {
+        .arm => switch (builtin.os.tag) {
             .linux => switch (reg_number) {
                 0 => mem.asBytes(&ucontext_ptr.mcontext.arm_r0),
                 1 => mem.asBytes(&ucontext_ptr.mcontext.arm_r1),
@@ -341,7 +292,7 @@ pub fn regBytes(
             },
             else => error.UnimplementedOs,
         },
-        .aarch64 => switch (native_os) {
+        .aarch64 => switch (builtin.os.tag) {
             .macos, .ios => switch (reg_number) {
                 0...28 => mem.asBytes(&ucontext_ptr.mcontext.ss.regs[reg_number]),
                 29 => mem.asBytes(&ucontext_ptr.mcontext.ss.fp),
@@ -389,22 +340,14 @@ pub fn regBytes(
     };
 }
 
-/// Returns the ABI-defined default value this register has in the unwinding table
-/// before running any of the CIE instructions. The DWARF spec defines these as having
-/// the .undefined rule by default, but allows ABI authors to override that.
-pub fn getRegDefaultValue(reg_number: u8, context: *std.debug.Dwarf.UnwindContext, out: []u8) !void {
-    switch (builtin.cpu.arch) {
-        .aarch64 => {
-            // Callee-saved registers are initialized as if they had the .same_value rule
-            if (reg_number >= 19 and reg_number <= 28) {
-                const src = try regBytes(context.thread_context, reg_number, context.reg_context);
-                if (src.len != out.len) return error.RegisterSizeMismatch;
-                @memcpy(out, src);
-                return;
-            }
-        },
-        else => {},
-    }
-
-    @memset(out, undefined);
+/// Returns a pointer to a register stored in a ThreadContext, preserving the
+/// pointer attributes of the context.
+pub fn regValueNative(
+    thread_context_ptr: *std.debug.ThreadContext,
+    reg_number: u8,
+    reg_context: ?RegisterContext,
+) !*align(1) usize {
+    const reg_bytes = try regBytes(thread_context_ptr, reg_number, reg_context);
+    if (@sizeOf(usize) != reg_bytes.len) return error.IncompatibleRegisterSize;
+    return mem.bytesAsValue(usize, reg_bytes[0..@sizeOf(usize)]);
 }
diff --git a/lib/std/debug/Dwarf/call_frame.zig b/lib/std/debug/Dwarf/call_frame.zig
index 73e00d3099..3e3d2585db 100644
--- a/lib/std/debug/Dwarf/call_frame.zig
+++ b/lib/std/debug/Dwarf/call_frame.zig
@@ -297,391 +297,3 @@ pub const Instruction = union(Opcode) {
         }
     }
 };
-
-/// Since register rules are applied (usually) during a panic,
-/// checked addition / subtraction is used so that we can return
-/// an error and fall back to FP-based unwinding.
-pub fn applyOffset(base: usize, offset: i64) !usize {
-    return if (offset >= 0)
-        try std.math.add(usize, base, @as(usize, @intCast(offset)))
-    else
-        try std.math.sub(usize, base, @as(usize, @intCast(-offset)));
-}
-
-/// This is a virtual machine that runs DWARF call frame instructions.
-pub const VirtualMachine = struct {
-    /// See section 6.4.1 of the DWARF5 specification for details on each
-    const RegisterRule = union(enum) {
-        // The spec says that the default rule for each column is the undefined rule.
-        // However, it also allows ABI / compiler authors to specify alternate defaults, so
-        // there is a distinction made here.
-        default: void,
-
-        undefined: void,
-        same_value: void,
-
-        // offset(N)
-        offset: i64,
-
-        // val_offset(N)
-        val_offset: i64,
-
-        // register(R)
-        register: u8,
-
-        // expression(E)
-        expression: []const u8,
-
-        // val_expression(E)
-        val_expression: []const u8,
-
-        // Augmenter-defined rule
-        architectural: void,
-    };
-
-    /// Each row contains unwinding rules for a set of registers.
-    pub const Row = struct {
-        /// Offset from `FrameDescriptionEntry.pc_begin`
-        offset: u64 = 0,
-
-        /// Special-case column that defines the CFA (Canonical Frame Address) rule.
-        /// The register field of this column defines the register that CFA is derived from.
-        cfa: Column = .{},
-
-        /// The register fields in these columns define the register the rule applies to.
-        columns: ColumnRange = .{},
-
-        /// Indicates that the next write to any column in this row needs to copy
-        /// the backing column storage first, as it may be referenced by previous rows.
-        copy_on_write: bool = false,
-    };
-
-    pub const Column = struct {
-        register: ?u8 = null,
-        rule: RegisterRule = .{ .default = {} },
-
-        /// Resolves the register rule and places the result into `out` (see dwarf.abi.regBytes)
-        pub fn resolveValue(
-            self: Column,
-            context: *std.debug.Dwarf.UnwindContext,
-            expression_context: std.debug.Dwarf.expression.Context,
-            ma: *debug.StackIterator.MemoryAccessor,
-            out: []u8,
-        ) !void {
-            switch (self.rule) {
-                .default => {
-                    const register = self.register orelse return error.InvalidRegister;
-                    try abi.getRegDefaultValue(register, context, out);
-                },
-                .undefined => {
-                    @memset(out, undefined);
-                },
-                .same_value => {
-                    // TODO: This copy could be eliminated if callers always copy the state then call this function to update it
-                    const register = self.register orelse return error.InvalidRegister;
-                    const src = try abi.regBytes(context.thread_context, register, context.reg_context);
-                    if (src.len != out.len) return error.RegisterSizeMismatch;
-                    @memcpy(out, src);
-                },
-                .offset => |offset| {
-                    if (context.cfa) |cfa| {
-                        const addr = try applyOffset(cfa, offset);
-                        if (ma.load(usize, addr) == null) return error.InvalidAddress;
-                        const ptr: *const usize = @ptrFromInt(addr);
-                        mem.writeInt(usize, out[0..@sizeOf(usize)], ptr.*, native_endian);
-                    } else return error.InvalidCFA;
-                },
-                .val_offset => |offset| {
-                    if (context.cfa) |cfa| {
-                        mem.writeInt(usize, out[0..@sizeOf(usize)], try applyOffset(cfa, offset), native_endian);
-                    } else return error.InvalidCFA;
-                },
-                .register => |register| {
-                    const src = try abi.regBytes(context.thread_context, register, context.reg_context);
-                    if (src.len != out.len) return error.RegisterSizeMismatch;
-                    @memcpy(out, try abi.regBytes(context.thread_context, register, context.reg_context));
-                },
-                .expression => |expression| {
-                    context.stack_machine.reset();
-                    const value = try context.stack_machine.run(expression, context.allocator, expression_context, context.cfa.?);
-                    const addr = if (value) |v| blk: {
-                        if (v != .generic) return error.InvalidExpressionValue;
-                        break :blk v.generic;
-                    } else return error.NoExpressionValue;
-
-                    if (ma.load(usize, addr) == null) return error.InvalidExpressionAddress;
-                    const ptr: *usize = @ptrFromInt(addr);
-                    mem.writeInt(usize, out[0..@sizeOf(usize)], ptr.*, native_endian);
-                },
-                .val_expression => |expression| {
-                    context.stack_machine.reset();
-                    const value = try context.stack_machine.run(expression, context.allocator, expression_context, context.cfa.?);
-                    if (value) |v| {
-                        if (v != .generic) return error.InvalidExpressionValue;
-                        mem.writeInt(usize, out[0..@sizeOf(usize)], v.generic, native_endian);
-                    } else return error.NoExpressionValue;
-                },
-                .architectural => return error.UnimplementedRegisterRule,
-            }
-        }
-    };
-
-    const ColumnRange = struct {
-        /// Index into `columns` of the first column in this row.
-        start: usize = undefined,
-        len: u8 = 0,
-    };
-
-    columns: std.ArrayListUnmanaged(Column) = .{},
-    stack: std.ArrayListUnmanaged(ColumnRange) = .{},
-    current_row: Row = .{},
-
-    /// The result of executing the CIE's initial_instructions
-    cie_row: ?Row = null,
-
-    pub fn deinit(self: *VirtualMachine, allocator: std.mem.Allocator) void {
-        self.stack.deinit(allocator);
-        self.columns.deinit(allocator);
-        self.* = undefined;
-    }
-
-    pub fn reset(self: *VirtualMachine) void {
-        self.stack.clearRetainingCapacity();
-        self.columns.clearRetainingCapacity();
-        self.current_row = .{};
-        self.cie_row = null;
-    }
-
-    /// Return a slice backed by the row's non-CFA columns
-    pub fn rowColumns(self: VirtualMachine, row: Row) []Column {
-        if (row.columns.len == 0) return &.{};
-        return self.columns.items[row.columns.start..][0..row.columns.len];
-    }
-
-    /// Either retrieves or adds a column for `register` (non-CFA) in the current row.
-    fn getOrAddColumn(self: *VirtualMachine, allocator: std.mem.Allocator, register: u8) !*Column {
-        for (self.rowColumns(self.current_row)) |*c| {
-            if (c.register == register) return c;
-        }
-
-        if (self.current_row.columns.len == 0) {
-            self.current_row.columns.start = self.columns.items.len;
-        }
-        self.current_row.columns.len += 1;
-
-        const column = try self.columns.addOne(allocator);
-        column.* = .{
-            .register = register,
-        };
-
-        return column;
-    }
-
-    /// Runs the CIE instructions, then the FDE instructions. Execution halts
-    /// once the row that corresponds to `pc` is known, and the row is returned.
-    pub fn runTo(
-        self: *VirtualMachine,
-        allocator: std.mem.Allocator,
-        pc: u64,
-        cie: std.debug.Dwarf.CommonInformationEntry,
-        fde: std.debug.Dwarf.FrameDescriptionEntry,
-        addr_size_bytes: u8,
-        endian: std.builtin.Endian,
-    ) !Row {
-        assert(self.cie_row == null);
-        if (pc < fde.pc_begin or pc >= fde.pc_begin + fde.pc_range) return error.AddressOutOfRange;
-
-        var prev_row: Row = self.current_row;
-
-        var cie_stream = std.io.fixedBufferStream(cie.initial_instructions);
-        var fde_stream = std.io.fixedBufferStream(fde.instructions);
-        var streams = [_]*std.io.FixedBufferStream([]const u8){
-            &cie_stream,
-            &fde_stream,
-        };
-
-        for (&streams, 0..) |stream, i| {
-            while (stream.pos < stream.buffer.len) {
-                const instruction = try std.debug.Dwarf.call_frame.Instruction.read(stream, addr_size_bytes, endian);
-                prev_row = try self.step(allocator, cie, i == 0, instruction);
-                if (pc < fde.pc_begin + self.current_row.offset) return prev_row;
-            }
-        }
-
-        return self.current_row;
-    }
-
-    pub fn runToNative(
-        self: *VirtualMachine,
-        allocator: std.mem.Allocator,
-        pc: u64,
-        cie: std.debug.Dwarf.CommonInformationEntry,
-        fde: std.debug.Dwarf.FrameDescriptionEntry,
-    ) !Row {
-        return self.runTo(allocator, pc, cie, fde, @sizeOf(usize), builtin.target.cpu.arch.endian());
-    }
-
-    fn resolveCopyOnWrite(self: *VirtualMachine, allocator: std.mem.Allocator) !void {
-        if (!self.current_row.copy_on_write) return;
-
-        const new_start = self.columns.items.len;
-        if (self.current_row.columns.len > 0) {
-            try self.columns.ensureUnusedCapacity(allocator, self.current_row.columns.len);
-            self.columns.appendSliceAssumeCapacity(self.rowColumns(self.current_row));
-            self.current_row.columns.start = new_start;
-        }
-    }
-
-    /// Executes a single instruction.
-    /// If this instruction is from the CIE, `is_initial` should be set.
-    /// Returns the value of `current_row` before executing this instruction.
-    pub fn step(
-        self: *VirtualMachine,
-        allocator: std.mem.Allocator,
-        cie: std.debug.Dwarf.CommonInformationEntry,
-        is_initial: bool,
-        instruction: Instruction,
-    ) !Row {
-        // CIE instructions must be run before FDE instructions
-        assert(!is_initial or self.cie_row == null);
-        if (!is_initial and self.cie_row == null) {
-            self.cie_row = self.current_row;
-            self.current_row.copy_on_write = true;
-        }
-
-        const prev_row = self.current_row;
-        switch (instruction) {
-            .set_loc => |i| {
-                if (i.address <= self.current_row.offset) return error.InvalidOperation;
-                // TODO: Check cie.segment_selector_size != 0 for DWARFV4
-                self.current_row.offset = i.address;
-            },
-            inline .advance_loc,
-            .advance_loc1,
-            .advance_loc2,
-            .advance_loc4,
-            => |i| {
-                self.current_row.offset += i.delta * cie.code_alignment_factor;
-                self.current_row.copy_on_write = true;
-            },
-            inline .offset,
-            .offset_extended,
-            .offset_extended_sf,
-            => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{ .offset = @as(i64, @intCast(i.offset)) * cie.data_alignment_factor };
-            },
-            inline .restore,
-            .restore_extended,
-            => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                if (self.cie_row) |cie_row| {
-                    const column = try self.getOrAddColumn(allocator, i.register);
-                    column.rule = for (self.rowColumns(cie_row)) |cie_column| {
-                        if (cie_column.register == i.register) break cie_column.rule;
-                    } else .{ .default = {} };
-                } else return error.InvalidOperation;
-            },
-            .nop => {},
-            .undefined => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{ .undefined = {} };
-            },
-            .same_value => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{ .same_value = {} };
-            },
-            .register => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{ .register = i.target_register };
-            },
-            .remember_state => {
-                try self.stack.append(allocator, self.current_row.columns);
-                self.current_row.copy_on_write = true;
-            },
-            .restore_state => {
-                const restored_columns = self.stack.popOrNull() orelse return error.InvalidOperation;
-                self.columns.shrinkRetainingCapacity(self.columns.items.len - self.current_row.columns.len);
-                try self.columns.ensureUnusedCapacity(allocator, restored_columns.len);
-
-                self.current_row.columns.start = self.columns.items.len;
-                self.current_row.columns.len = restored_columns.len;
-                self.columns.appendSliceAssumeCapacity(self.columns.items[restored_columns.start..][0..restored_columns.len]);
-            },
-            .def_cfa => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                self.current_row.cfa = .{
-                    .register = i.register,
-                    .rule = .{ .val_offset = @intCast(i.offset) },
-                };
-            },
-            .def_cfa_sf => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                self.current_row.cfa = .{
-                    .register = i.register,
-                    .rule = .{ .val_offset = i.offset * cie.data_alignment_factor },
-                };
-            },
-            .def_cfa_register => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
-                self.current_row.cfa.register = i.register;
-            },
-            .def_cfa_offset => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
-                self.current_row.cfa.rule = .{
-                    .val_offset = @intCast(i.offset),
-                };
-            },
-            .def_cfa_offset_sf => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
-                self.current_row.cfa.rule = .{
-                    .val_offset = i.offset * cie.data_alignment_factor,
-                };
-            },
-            .def_cfa_expression => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                self.current_row.cfa.register = undefined;
-                self.current_row.cfa.rule = .{
-                    .expression = i.block,
-                };
-            },
-            .expression => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{
-                    .expression = i.block,
-                };
-            },
-            .val_offset => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{
-                    .val_offset = @as(i64, @intCast(i.offset)) * cie.data_alignment_factor,
-                };
-            },
-            .val_offset_sf => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{
-                    .val_offset = i.offset * cie.data_alignment_factor,
-                };
-            },
-            .val_expression => |i| {
-                try self.resolveCopyOnWrite(allocator);
-                const column = try self.getOrAddColumn(allocator, i.register);
-                column.rule = .{
-                    .val_expression = i.block,
-                };
-            },
-        }
-
-        return prev_row;
-    }
-};
diff --git a/lib/std/debug/Dwarf/expression.zig b/lib/std/debug/Dwarf/expression.zig
index 6243ea9717..5fab56de6e 100644
--- a/lib/std/debug/Dwarf/expression.zig
+++ b/lib/std/debug/Dwarf/expression.zig
@@ -1,11 +1,13 @@
-const std = @import("std");
 const builtin = @import("builtin");
+const native_arch = builtin.cpu.arch;
+const native_endian = native_arch.endian();
+
+const std = @import("std");
 const leb = std.leb;
 const OP = std.dwarf.OP;
 const abi = std.debug.Dwarf.abi;
 const mem = std.mem;
 const assert = std.debug.assert;
-const native_endian = builtin.cpu.arch.endian();
 
 /// Expressions can be evaluated in different contexts, each requiring its own set of inputs.
 /// Callers should specify all the fields relevant to their context. If a field is required
@@ -14,7 +16,7 @@ pub const Context = struct {
     /// The dwarf format of the section this expression is in
     format: std.dwarf.Format = .@"32",
     /// If specified, any addresses will pass through before being accessed
-    memory_accessor: ?*std.debug.StackIterator.MemoryAccessor = null,
+    memory_accessor: ?*std.debug.MemoryAccessor = null,
     /// The compilation unit this expression relates to, if any
     compile_unit: ?*const std.debug.Dwarf.CompileUnit = null,
     /// When evaluating a user-presented expression, this is the address of the object being evaluated
@@ -34,7 +36,7 @@ pub const Options = struct {
     /// The address size of the target architecture
     addr_size: u8 = @sizeOf(usize),
     /// Endianness of the target architecture
-    endian: std.builtin.Endian = builtin.target.cpu.arch.endian(),
+    endian: std.builtin.Endian = native_endian,
     /// Restrict the stack machine to a subset of opcodes used in call frame instructions
     call_frame_context: bool = false,
 };
@@ -60,7 +62,7 @@ pub const Error = error{
     InvalidTypeLength,
 
     TruncatedIntegralType,
-} || abi.AbiError || error{ EndOfStream, Overflow, OutOfMemory, DivisionByZero };
+} || abi.RegBytesError || error{ EndOfStream, Overflow, OutOfMemory, DivisionByZero };
 
 /// A stack machine that can decode and run DWARF expressions.
 /// Expressions can be decoded for non-native address size and endianness,
@@ -304,7 +306,7 @@ pub fn StackMachine(comptime options: Options) type {
             allocator: std.mem.Allocator,
             context: Context,
         ) Error!bool {
-            if (@sizeOf(usize) != @sizeOf(addr_type) or options.endian != comptime builtin.target.cpu.arch.endian())
+            if (@sizeOf(usize) != @sizeOf(addr_type) or options.endian != native_endian)
                 @compileError("Execution of non-native address sizes / endianness is not supported");
 
             const opcode = try stream.reader().readByte();
@@ -1186,13 +1188,13 @@ test "DWARF expressions" {
             // TODO: Test fbreg (once implemented): mock a DIE and point compile_unit.frame_base at it
 
             mem.writeInt(usize, reg_bytes[0..@sizeOf(usize)], 0xee, native_endian);
-            (try abi.regValueNative(usize, &thread_context, abi.fpRegNum(reg_context), reg_context)).* = 1;
-            (try abi.regValueNative(usize, &thread_context, abi.spRegNum(reg_context), reg_context)).* = 2;
-            (try abi.regValueNative(usize, &thread_context, abi.ipRegNum(), reg_context)).* = 3;
+            (try abi.regValueNative(&thread_context, abi.fpRegNum(native_arch, reg_context), reg_context)).* = 1;
+            (try abi.regValueNative(&thread_context, abi.spRegNum(native_arch, reg_context), reg_context)).* = 2;
+            (try abi.regValueNative(&thread_context, abi.ipRegNum(native_arch).?, reg_context)).* = 3;
 
-            try b.writeBreg(writer, abi.fpRegNum(reg_context), @as(usize, 100));
-            try b.writeBreg(writer, abi.spRegNum(reg_context), @as(usize, 200));
-            try b.writeBregx(writer, abi.ipRegNum(), @as(usize, 300));
+            try b.writeBreg(writer, abi.fpRegNum(native_arch, reg_context), @as(usize, 100));
+            try b.writeBreg(writer, abi.spRegNum(native_arch, reg_context), @as(usize, 200));
+            try b.writeBregx(writer, abi.ipRegNum(native_arch).?, @as(usize, 300));
             try b.writeRegvalType(writer, @as(u8, 0), @as(usize, 400));
 
             _ = try stack_machine.run(program.items, allocator, context, 0);
diff --git a/lib/std/debug/MemoryAccessor.zig b/lib/std/debug/MemoryAccessor.zig
new file mode 100644
index 0000000000..bfdda609f6
--- /dev/null
+++ b/lib/std/debug/MemoryAccessor.zig
@@ -0,0 +1,128 @@
+//! Reads memory from any address of the current location using OS-specific
+//! syscalls, bypassing memory page protection. Useful for stack unwinding.
+
+const builtin = @import("builtin");
+const native_os = builtin.os.tag;
+
+const std = @import("../std.zig");
+const posix = std.posix;
+const File = std.fs.File;
+const page_size = std.mem.page_size;
+
+const MemoryAccessor = @This();
+
+var cached_pid: posix.pid_t = -1;
+
+mem: switch (native_os) {
+    .linux => File,
+    else => void,
+},
+
+pub const init: MemoryAccessor = .{
+    .mem = switch (native_os) {
+        .linux => .{ .handle = -1 },
+        else => {},
+    },
+};
+
+fn read(ma: *MemoryAccessor, address: usize, buf: []u8) bool {
+    switch (native_os) {
+        .linux => while (true) switch (ma.mem.handle) {
+            -2 => break,
+            -1 => {
+                const linux = std.os.linux;
+                const pid = switch (@atomicLoad(posix.pid_t, &cached_pid, .monotonic)) {
+                    -1 => pid: {
+                        const pid = linux.getpid();
+                        @atomicStore(posix.pid_t, &cached_pid, pid, .monotonic);
+                        break :pid pid;
+                    },
+                    else => |pid| pid,
+                };
+                const bytes_read = linux.process_vm_readv(
+                    pid,
+                    &.{.{ .base = buf.ptr, .len = buf.len }},
+                    &.{.{ .base = @ptrFromInt(address), .len = buf.len }},
+                    0,
+                );
+                switch (linux.E.init(bytes_read)) {
+                    .SUCCESS => return bytes_read == buf.len,
+                    .FAULT => return false,
+                    .INVAL, .PERM, .SRCH => unreachable, // own pid is always valid
+                    .NOMEM => {},
+                    .NOSYS => {}, // QEMU is known not to implement this syscall.
+                    else => unreachable, // unexpected
+                }
+                var path_buf: [
+                    std.fmt.count("/proc/{d}/mem", .{std.math.minInt(posix.pid_t)})
+                ]u8 = undefined;
+                const path = std.fmt.bufPrint(&path_buf, "/proc/{d}/mem", .{pid}) catch
+                    unreachable;
+                ma.mem = std.fs.openFileAbsolute(path, .{}) catch {
+                    ma.mem.handle = -2;
+                    break;
+                };
+            },
+            else => return (ma.mem.pread(buf, address) catch return false) == buf.len,
+        },
+        else => {},
+    }
+    if (!isValidMemory(address)) return false;
+    @memcpy(buf, @as([*]const u8, @ptrFromInt(address)));
+    return true;
+}
+
+pub fn load(ma: *MemoryAccessor, comptime Type: type, address: usize) ?Type {
+    var result: Type = undefined;
+    return if (ma.read(address, std.mem.asBytes(&result))) result else null;
+}
+
+pub fn isValidMemory(address: usize) bool {
+    // We are unable to determine validity of memory for freestanding targets
+    if (native_os == .freestanding or native_os == .uefi) return true;
+
+    const aligned_address = address & ~@as(usize, @intCast((page_size - 1)));
+    if (aligned_address == 0) return false;
+    const aligned_memory = @as([*]align(page_size) u8, @ptrFromInt(aligned_address))[0..page_size];
+
+    if (native_os == .windows) {
+        const windows = std.os.windows;
+
+        var memory_info: windows.MEMORY_BASIC_INFORMATION = undefined;
+
+        // The only error this function can throw is ERROR_INVALID_PARAMETER.
+        // supply an address that invalid i'll be thrown.
+        const rc = windows.VirtualQuery(aligned_memory, &memory_info, aligned_memory.len) catch {
+            return false;
+        };
+
+        // Result code has to be bigger than zero (number of bytes written)
+        if (rc == 0) {
+            return false;
+        }
+
+        // Free pages cannot be read, they are unmapped
+        if (memory_info.State == windows.MEM_FREE) {
+            return false;
+        }
+
+        return true;
+    } else if (have_msync) {
+        posix.msync(aligned_memory, posix.MSF.ASYNC) catch |err| {
+            switch (err) {
+                error.UnmappedMemory => return false,
+                else => unreachable,
+            }
+        };
+
+        return true;
+    } else {
+        // We are unable to determine validity of memory on this target.
+        return true;
+    }
+}
+
+const have_msync = switch (native_os) {
+    .wasi, .emscripten, .windows => false,
+    else => true,
+};
diff --git a/lib/std/debug/Pdb.zig b/lib/std/debug/Pdb.zig
new file mode 100644
index 0000000000..bdcc108c1d
--- /dev/null
+++ b/lib/std/debug/Pdb.zig
@@ -0,0 +1,591 @@
+const std = @import("../std.zig");
+const File = std.fs.File;
+const Allocator = std.mem.Allocator;
+const pdb = std.pdb;
+
+const Pdb = @This();
+
+in_file: File,
+msf: Msf,
+allocator: Allocator,
+string_table: ?*MsfStream,
+dbi: ?*MsfStream,
+modules: []Module,
+sect_contribs: []pdb.SectionContribEntry,
+guid: [16]u8,
+age: u32,
+
+pub const Module = struct {
+    mod_info: pdb.ModInfo,
+    module_name: []u8,
+    obj_file_name: []u8,
+    // The fields below are filled on demand.
+    populated: bool,
+    symbols: []u8,
+    subsect_info: []u8,
+    checksum_offset: ?usize,
+
+    pub fn deinit(self: *Module, allocator: Allocator) void {
+        allocator.free(self.module_name);
+        allocator.free(self.obj_file_name);
+        if (self.populated) {
+            allocator.free(self.symbols);
+            allocator.free(self.subsect_info);
+        }
+    }
+};
+
+pub fn init(allocator: Allocator, path: []const u8) !Pdb {
+    const file = try std.fs.cwd().openFile(path, .{});
+    errdefer file.close();
+
+    return .{
+        .in_file = file,
+        .allocator = allocator,
+        .string_table = null,
+        .dbi = null,
+        .msf = try Msf.init(allocator, file),
+        .modules = &[_]Module{},
+        .sect_contribs = &[_]pdb.SectionContribEntry{},
+        .guid = undefined,
+        .age = undefined,
+    };
+}
+
+pub fn deinit(self: *Pdb) void {
+    self.in_file.close();
+    self.msf.deinit(self.allocator);
+    for (self.modules) |*module| {
+        module.deinit(self.allocator);
+    }
+    self.allocator.free(self.modules);
+    self.allocator.free(self.sect_contribs);
+}
+
+pub fn parseDbiStream(self: *Pdb) !void {
+    var stream = self.getStream(pdb.StreamType.Dbi) orelse
+        return error.InvalidDebugInfo;
+    const reader = stream.reader();
+
+    const header = try reader.readStruct(std.pdb.DbiStreamHeader);
+    if (header.VersionHeader != 19990903) // V70, only value observed by LLVM team
+        return error.UnknownPDBVersion;
+    // if (header.Age != age)
+    //     return error.UnmatchingPDB;
+
+    const mod_info_size = header.ModInfoSize;
+    const section_contrib_size = header.SectionContributionSize;
+
+    var modules = std.ArrayList(Module).init(self.allocator);
+    errdefer modules.deinit();
+
+    // Module Info Substream
+    var mod_info_offset: usize = 0;
+    while (mod_info_offset != mod_info_size) {
+        const mod_info = try reader.readStruct(pdb.ModInfo);
+        var this_record_len: usize = @sizeOf(pdb.ModInfo);
+
+        const module_name = try reader.readUntilDelimiterAlloc(self.allocator, 0, 1024);
+        errdefer self.allocator.free(module_name);
+        this_record_len += module_name.len + 1;
+
+        const obj_file_name = try reader.readUntilDelimiterAlloc(self.allocator, 0, 1024);
+        errdefer self.allocator.free(obj_file_name);
+        this_record_len += obj_file_name.len + 1;
+
+        if (this_record_len % 4 != 0) {
+            const round_to_next_4 = (this_record_len | 0x3) + 1;
+            const march_forward_bytes = round_to_next_4 - this_record_len;
+            try stream.seekBy(@as(isize, @intCast(march_forward_bytes)));
+            this_record_len += march_forward_bytes;
+        }
+
+        try modules.append(Module{
+            .mod_info = mod_info,
+            .module_name = module_name,
+            .obj_file_name = obj_file_name,
+
+            .populated = false,
+            .symbols = undefined,
+            .subsect_info = undefined,
+            .checksum_offset = null,
+        });
+
+        mod_info_offset += this_record_len;
+        if (mod_info_offset > mod_info_size)
+            return error.InvalidDebugInfo;
+    }
+
+    // Section Contribution Substream
+    var sect_contribs = std.ArrayList(pdb.SectionContribEntry).init(self.allocator);
+    errdefer sect_contribs.deinit();
+
+    var sect_cont_offset: usize = 0;
+    if (section_contrib_size != 0) {
+        const version = reader.readEnum(std.pdb.SectionContrSubstreamVersion, .little) catch |err| switch (err) {
+            error.InvalidValue => return error.InvalidDebugInfo,
+            else => |e| return e,
+        };
+        _ = version;
+        sect_cont_offset += @sizeOf(u32);
+    }
+    while (sect_cont_offset != section_contrib_size) {
+        const entry = try sect_contribs.addOne();
+        entry.* = try reader.readStruct(pdb.SectionContribEntry);
+        sect_cont_offset += @sizeOf(pdb.SectionContribEntry);
+
+        if (sect_cont_offset > section_contrib_size)
+            return error.InvalidDebugInfo;
+    }
+
+    self.modules = try modules.toOwnedSlice();
+    self.sect_contribs = try sect_contribs.toOwnedSlice();
+}
+
+pub fn parseInfoStream(self: *Pdb) !void {
+    var stream = self.getStream(pdb.StreamType.Pdb) orelse
+        return error.InvalidDebugInfo;
+    const reader = stream.reader();
+
+    // Parse the InfoStreamHeader.
+    const version = try reader.readInt(u32, .little);
+    const signature = try reader.readInt(u32, .little);
+    _ = signature;
+    const age = try reader.readInt(u32, .little);
+    const guid = try reader.readBytesNoEof(16);
+
+    if (version != 20000404) // VC70, only value observed by LLVM team
+        return error.UnknownPDBVersion;
+
+    self.guid = guid;
+    self.age = age;
+
+    // Find the string table.
+    const string_table_index = str_tab_index: {
+        const name_bytes_len = try reader.readInt(u32, .little);
+        const name_bytes = try self.allocator.alloc(u8, name_bytes_len);
+        defer self.allocator.free(name_bytes);
+        try reader.readNoEof(name_bytes);
+
+        const HashTableHeader = extern struct {
+            Size: u32,
+            Capacity: u32,
+
+            fn maxLoad(cap: u32) u32 {
+                return cap * 2 / 3 + 1;
+            }
+        };
+        const hash_tbl_hdr = try reader.readStruct(HashTableHeader);
+        if (hash_tbl_hdr.Capacity == 0)
+            return error.InvalidDebugInfo;
+
+        if (hash_tbl_hdr.Size > HashTableHeader.maxLoad(hash_tbl_hdr.Capacity))
+            return error.InvalidDebugInfo;
+
+        const present = try readSparseBitVector(&reader, self.allocator);
+        defer self.allocator.free(present);
+        if (present.len != hash_tbl_hdr.Size)
+            return error.InvalidDebugInfo;
+        const deleted = try readSparseBitVector(&reader, self.allocator);
+        defer self.allocator.free(deleted);
+
+        for (present) |_| {
+            const name_offset = try reader.readInt(u32, .little);
+            const name_index = try reader.readInt(u32, .little);
+            if (name_offset > name_bytes.len)
+                return error.InvalidDebugInfo;
+            const name = std.mem.sliceTo(name_bytes[name_offset..], 0);
+            if (std.mem.eql(u8, name, "/names")) {
+                break :str_tab_index name_index;
+            }
+        }
+        return error.MissingDebugInfo;
+    };
+
+    self.string_table = self.getStreamById(string_table_index) orelse
+        return error.MissingDebugInfo;
+}
+
+pub fn getSymbolName(self: *Pdb, module: *Module, address: u64) ?[]const u8 {
+    _ = self;
+    std.debug.assert(module.populated);
+
+    var symbol_i: usize = 0;
+    while (symbol_i != module.symbols.len) {
+        const prefix = @as(*align(1) pdb.RecordPrefix, @ptrCast(&module.symbols[symbol_i]));
+        if (prefix.RecordLen < 2)
+            return null;
+        switch (prefix.RecordKind) {
+            .S_LPROC32, .S_GPROC32 => {
+                const proc_sym = @as(*align(1) pdb.ProcSym, @ptrCast(&module.symbols[symbol_i + @sizeOf(pdb.RecordPrefix)]));
+                if (address >= proc_sym.CodeOffset and address < proc_sym.CodeOffset + proc_sym.CodeSize) {
+                    return std.mem.sliceTo(@as([*:0]u8, @ptrCast(&proc_sym.Name[0])), 0);
+                }
+            },
+            else => {},
+        }
+        symbol_i += prefix.RecordLen + @sizeOf(u16);
+    }
+
+    return null;
+}
+
+pub fn getLineNumberInfo(self: *Pdb, module: *Module, address: u64) !std.debug.SourceLocation {
+    std.debug.assert(module.populated);
+    const subsect_info = module.subsect_info;
+
+    var sect_offset: usize = 0;
+    var skip_len: usize = undefined;
+    const checksum_offset = module.checksum_offset orelse return error.MissingDebugInfo;
+    while (sect_offset != subsect_info.len) : (sect_offset += skip_len) {
+        const subsect_hdr = @as(*align(1) pdb.DebugSubsectionHeader, @ptrCast(&subsect_info[sect_offset]));
+        skip_len = subsect_hdr.Length;
+        sect_offset += @sizeOf(pdb.DebugSubsectionHeader);
+
+        switch (subsect_hdr.Kind) {
+            .Lines => {
+                var line_index = sect_offset;
+
+                const line_hdr = @as(*align(1) pdb.LineFragmentHeader, @ptrCast(&subsect_info[line_index]));
+                if (line_hdr.RelocSegment == 0)
+                    return error.MissingDebugInfo;
+                line_index += @sizeOf(pdb.LineFragmentHeader);
+                const frag_vaddr_start = line_hdr.RelocOffset;
+                const frag_vaddr_end = frag_vaddr_start + line_hdr.CodeSize;
+
+                if (address >= frag_vaddr_start and address < frag_vaddr_end) {
+                    // There is an unknown number of LineBlockFragmentHeaders (and their accompanying line and column records)
+                    // from now on. We will iterate through them, and eventually find a SourceLocation that we're interested in,
+                    // breaking out to :subsections. If not, we will make sure to not read anything outside of this subsection.
+                    const subsection_end_index = sect_offset + subsect_hdr.Length;
+
+                    while (line_index < subsection_end_index) {
+                        const block_hdr = @as(*align(1) pdb.LineBlockFragmentHeader, @ptrCast(&subsect_info[line_index]));
+                        line_index += @sizeOf(pdb.LineBlockFragmentHeader);
+                        const start_line_index = line_index;
+
+                        const has_column = line_hdr.Flags.LF_HaveColumns;
+
+                        // All line entries are stored inside their line block by ascending start address.
+                        // Heuristic: we want to find the last line entry
+                        // that has a vaddr_start <= address.
+                        // This is done with a simple linear search.
+                        var line_i: u32 = 0;
+                        while (line_i < block_hdr.NumLines) : (line_i += 1) {
+                            const line_num_entry = @as(*align(1) pdb.LineNumberEntry, @ptrCast(&subsect_info[line_index]));
+                            line_index += @sizeOf(pdb.LineNumberEntry);
+
+                            const vaddr_start = frag_vaddr_start + line_num_entry.Offset;
+                            if (address < vaddr_start) {
+                                break;
+                            }
+                        }
+
+                        // line_i == 0 would mean that no matching pdb.LineNumberEntry was found.
+                        if (line_i > 0) {
+                            const subsect_index = checksum_offset + block_hdr.NameIndex;
+                            const chksum_hdr = @as(*align(1) pdb.FileChecksumEntryHeader, @ptrCast(&module.subsect_info[subsect_index]));
+                            const strtab_offset = @sizeOf(pdb.StringTableHeader) + chksum_hdr.FileNameOffset;
+                            try self.string_table.?.seekTo(strtab_offset);
+                            const source_file_name = try self.string_table.?.reader().readUntilDelimiterAlloc(self.allocator, 0, 1024);
+
+                            const line_entry_idx = line_i - 1;
+
+                            const column = if (has_column) blk: {
+                                const start_col_index = start_line_index + @sizeOf(pdb.LineNumberEntry) * block_hdr.NumLines;
+                                const col_index = start_col_index + @sizeOf(pdb.ColumnNumberEntry) * line_entry_idx;
+                                const col_num_entry = @as(*align(1) pdb.ColumnNumberEntry, @ptrCast(&subsect_info[col_index]));
+                                break :blk col_num_entry.StartColumn;
+                            } else 0;
+
+                            const found_line_index = start_line_index + line_entry_idx * @sizeOf(pdb.LineNumberEntry);
+                            const line_num_entry: *align(1) pdb.LineNumberEntry = @ptrCast(&subsect_info[found_line_index]);
+                            const flags: *align(1) pdb.LineNumberEntry.Flags = @ptrCast(&line_num_entry.Flags);
+
+                            return .{
+                                .file_name = source_file_name,
+                                .line = flags.Start,
+                                .column = column,
+                            };
+                        }
+                    }
+
+                    // Checking that we are not reading garbage after the (possibly) multiple block fragments.
+                    if (line_index != subsection_end_index) {
+                        return error.InvalidDebugInfo;
+                    }
+                }
+            },
+            else => {},
+        }
+
+        if (sect_offset > subsect_info.len)
+            return error.InvalidDebugInfo;
+    }
+
+    return error.MissingDebugInfo;
+}
+
+pub fn getModule(self: *Pdb, index: usize) !?*Module {
+    if (index >= self.modules.len)
+        return null;
+
+    const mod = &self.modules[index];
+    if (mod.populated)
+        return mod;
+
+    // At most one can be non-zero.
+    if (mod.mod_info.C11ByteSize != 0 and mod.mod_info.C13ByteSize != 0)
+        return error.InvalidDebugInfo;
+    if (mod.mod_info.C13ByteSize == 0)
+        return error.InvalidDebugInfo;
+
+    const stream = self.getStreamById(mod.mod_info.ModuleSymStream) orelse
+        return error.MissingDebugInfo;
+    const reader = stream.reader();
+
+    const signature = try reader.readInt(u32, .little);
+    if (signature != 4)
+        return error.InvalidDebugInfo;
+
+    mod.symbols = try self.allocator.alloc(u8, mod.mod_info.SymByteSize - 4);
+    errdefer self.allocator.free(mod.symbols);
+    try reader.readNoEof(mod.symbols);
+
+    mod.subsect_info = try self.allocator.alloc(u8, mod.mod_info.C13ByteSize);
+    errdefer self.allocator.free(mod.subsect_info);
+    try reader.readNoEof(mod.subsect_info);
+
+    var sect_offset: usize = 0;
+    var skip_len: usize = undefined;
+    while (sect_offset != mod.subsect_info.len) : (sect_offset += skip_len) {
+        const subsect_hdr = @as(*align(1) pdb.DebugSubsectionHeader, @ptrCast(&mod.subsect_info[sect_offset]));
+        skip_len = subsect_hdr.Length;
+        sect_offset += @sizeOf(pdb.DebugSubsectionHeader);
+
+        switch (subsect_hdr.Kind) {
+            .FileChecksums => {
+                mod.checksum_offset = sect_offset;
+                break;
+            },
+            else => {},
+        }
+
+        if (sect_offset > mod.subsect_info.len)
+            return error.InvalidDebugInfo;
+    }
+
+    mod.populated = true;
+    return mod;
+}
+
+pub fn getStreamById(self: *Pdb, id: u32) ?*MsfStream {
+    if (id >= self.msf.streams.len)
+        return null;
+    return &self.msf.streams[id];
+}
+
+pub fn getStream(self: *Pdb, stream: pdb.StreamType) ?*MsfStream {
+    const id = @intFromEnum(stream);
+    return self.getStreamById(id);
+}
+
+/// https://llvm.org/docs/PDB/MsfFile.html
+const Msf = struct {
+    directory: MsfStream,
+    streams: []MsfStream,
+
+    fn init(allocator: Allocator, file: File) !Msf {
+        const in = file.reader();
+
+        const superblock = try in.readStruct(pdb.SuperBlock);
+
+        // Sanity checks
+        if (!std.mem.eql(u8, &superblock.FileMagic, pdb.SuperBlock.file_magic))
+            return error.InvalidDebugInfo;
+        if (superblock.FreeBlockMapBlock != 1 and superblock.FreeBlockMapBlock != 2)
+            return error.InvalidDebugInfo;
+        const file_len = try file.getEndPos();
+        if (superblock.NumBlocks * superblock.BlockSize != file_len)
+            return error.InvalidDebugInfo;
+        switch (superblock.BlockSize) {
+            // llvm only supports 4096 but we can handle any of these values
+            512, 1024, 2048, 4096 => {},
+            else => return error.InvalidDebugInfo,
+        }
+
+        const dir_block_count = blockCountFromSize(superblock.NumDirectoryBytes, superblock.BlockSize);
+        if (dir_block_count > superblock.BlockSize / @sizeOf(u32))
+            return error.UnhandledBigDirectoryStream; // cf. BlockMapAddr comment.
+
+        try file.seekTo(superblock.BlockSize * superblock.BlockMapAddr);
+        const dir_blocks = try allocator.alloc(u32, dir_block_count);
+        for (dir_blocks) |*b| {
+            b.* = try in.readInt(u32, .little);
+        }
+        var directory = MsfStream.init(
+            superblock.BlockSize,
+            file,
+            dir_blocks,
+        );
+
+        const begin = directory.pos;
+        const stream_count = try directory.reader().readInt(u32, .little);
+        const stream_sizes = try allocator.alloc(u32, stream_count);
+        defer allocator.free(stream_sizes);
+
+        // Microsoft's implementation uses @as(u32, -1) for inexistent streams.
+        // These streams are not used, but still participate in the file
+        // and must be taken into account when resolving stream indices.
+        const Nil = 0xFFFFFFFF;
+        for (stream_sizes) |*s| {
+            const size = try directory.reader().readInt(u32, .little);
+            s.* = if (size == Nil) 0 else blockCountFromSize(size, superblock.BlockSize);
+        }
+
+        const streams = try allocator.alloc(MsfStream, stream_count);
+        for (streams, 0..) |*stream, i| {
+            const size = stream_sizes[i];
+            if (size == 0) {
+                stream.* = MsfStream{
+                    .blocks = &[_]u32{},
+                };
+            } else {
+                var blocks = try allocator.alloc(u32, size);
+                var j: u32 = 0;
+                while (j < size) : (j += 1) {
+                    const block_id = try directory.reader().readInt(u32, .little);
+                    const n = (block_id % superblock.BlockSize);
+                    // 0 is for pdb.SuperBlock, 1 and 2 for FPMs.
+                    if (block_id == 0 or n == 1 or n == 2 or block_id * superblock.BlockSize > file_len)
+                        return error.InvalidBlockIndex;
+                    blocks[j] = block_id;
+                }
+
+                stream.* = MsfStream.init(
+                    superblock.BlockSize,
+                    file,
+                    blocks,
+                );
+            }
+        }
+
+        const end = directory.pos;
+        if (end - begin != superblock.NumDirectoryBytes)
+            return error.InvalidStreamDirectory;
+
+        return Msf{
+            .directory = directory,
+            .streams = streams,
+        };
+    }
+
+    fn deinit(self: *Msf, allocator: Allocator) void {
+        allocator.free(self.directory.blocks);
+        for (self.streams) |*stream| {
+            allocator.free(stream.blocks);
+        }
+        allocator.free(self.streams);
+    }
+};
+
+const MsfStream = struct {
+    in_file: File = undefined,
+    pos: u64 = undefined,
+    blocks: []u32 = undefined,
+    block_size: u32 = undefined,
+
+    pub const Error = @typeInfo(@typeInfo(@TypeOf(read)).Fn.return_type.?).ErrorUnion.error_set;
+
+    fn init(block_size: u32, file: File, blocks: []u32) MsfStream {
+        const stream = MsfStream{
+            .in_file = file,
+            .pos = 0,
+            .blocks = blocks,
+            .block_size = block_size,
+        };
+
+        return stream;
+    }
+
+    fn read(self: *MsfStream, buffer: []u8) !usize {
+        var block_id = @as(usize, @intCast(self.pos / self.block_size));
+        if (block_id >= self.blocks.len) return 0; // End of Stream
+        var block = self.blocks[block_id];
+        var offset = self.pos % self.block_size;
+
+        try self.in_file.seekTo(block * self.block_size + offset);
+        const in = self.in_file.reader();
+
+        var size: usize = 0;
+        var rem_buffer = buffer;
+        while (size < buffer.len) {
+            const size_to_read = @min(self.block_size - offset, rem_buffer.len);
+            size += try in.read(rem_buffer[0..size_to_read]);
+            rem_buffer = buffer[size..];
+            offset += size_to_read;
+
+            // If we're at the end of a block, go to the next one.
+            if (offset == self.block_size) {
+                offset = 0;
+                block_id += 1;
+                if (block_id >= self.blocks.len) break; // End of Stream
+                block = self.blocks[block_id];
+                try self.in_file.seekTo(block * self.block_size);
+            }
+        }
+
+        self.pos += buffer.len;
+        return buffer.len;
+    }
+
+    pub fn seekBy(self: *MsfStream, len: i64) !void {
+        self.pos = @as(u64, @intCast(@as(i64, @intCast(self.pos)) + len));
+        if (self.pos >= self.blocks.len * self.block_size)
+            return error.EOF;
+    }
+
+    pub fn seekTo(self: *MsfStream, len: u64) !void {
+        self.pos = len;
+        if (self.pos >= self.blocks.len * self.block_size)
+            return error.EOF;
+    }
+
+    fn getSize(self: *const MsfStream) u64 {
+        return self.blocks.len * self.block_size;
+    }
+
+    fn getFilePos(self: MsfStream) u64 {
+        const block_id = self.pos / self.block_size;
+        const block = self.blocks[block_id];
+        const offset = self.pos % self.block_size;
+
+        return block * self.block_size + offset;
+    }
+
+    pub fn reader(self: *MsfStream) std.io.Reader(*MsfStream, Error, read) {
+        return .{ .context = self };
+    }
+};
+
+fn readSparseBitVector(stream: anytype, allocator: Allocator) ![]u32 {
+    const num_words = try stream.readInt(u32, .little);
+    var list = std.ArrayList(u32).init(allocator);
+    errdefer list.deinit();
+    var word_i: u32 = 0;
+    while (word_i != num_words) : (word_i += 1) {
+        const word = try stream.readInt(u32, .little);
+        var bit_i: u5 = 0;
+        while (true) : (bit_i += 1) {
+            if (word & (@as(u32, 1) << bit_i) != 0) {
+                try list.append(word_i * 32 + bit_i);
+            }
+            if (bit_i == std.math.maxInt(u5)) break;
+        }
+    }
+    return try list.toOwnedSlice();
+}
+
+fn blockCountFromSize(size: u32, block_size: u32) u32 {
+    return (size + block_size - 1) / block_size;
+}
diff --git a/lib/std/debug/SelfInfo.zig b/lib/std/debug/SelfInfo.zig
new file mode 100644
index 0000000000..c27f466fb3
--- /dev/null
+++ b/lib/std/debug/SelfInfo.zig
@@ -0,0 +1,2438 @@
+//! Cross-platform abstraction for this binary's own debug information, with a
+//! goal of minimal code bloat and compilation speed penalty.
+
+const builtin = @import("builtin");
+const native_os = builtin.os.tag;
+const native_endian = native_arch.endian();
+const native_arch = builtin.cpu.arch;
+
+const std = @import("../std.zig");
+const mem = std.mem;
+const Allocator = std.mem.Allocator;
+const windows = std.os.windows;
+const macho = std.macho;
+const fs = std.fs;
+const coff = std.coff;
+const pdb = std.pdb;
+const assert = std.debug.assert;
+const posix = std.posix;
+const elf = std.elf;
+const Dwarf = std.debug.Dwarf;
+const Pdb = std.debug.Pdb;
+const File = std.fs.File;
+const math = std.math;
+const testing = std.testing;
+const StackIterator = std.debug.StackIterator;
+const regBytes = Dwarf.abi.regBytes;
+const regValueNative = Dwarf.abi.regValueNative;
+
+const SelfInfo = @This();
+
+const root = @import("root");
+
+allocator: Allocator,
+address_map: std.AutoHashMap(usize, *Module),
+modules: if (native_os == .windows) std.ArrayListUnmanaged(WindowsModule) else void,
+
+pub const OpenError = error{
+    MissingDebugInfo,
+    UnsupportedOperatingSystem,
+} || @typeInfo(@typeInfo(@TypeOf(SelfInfo.init)).Fn.return_type.?).ErrorUnion.error_set;
+
+pub fn open(allocator: Allocator) OpenError!SelfInfo {
+    nosuspend {
+        if (builtin.strip_debug_info)
+            return error.MissingDebugInfo;
+        switch (native_os) {
+            .linux,
+            .freebsd,
+            .netbsd,
+            .dragonfly,
+            .openbsd,
+            .macos,
+            .solaris,
+            .illumos,
+            .windows,
+            => return try SelfInfo.init(allocator),
+            else => return error.UnsupportedOperatingSystem,
+        }
+    }
+}
+
+pub fn init(allocator: Allocator) !SelfInfo {
+    var debug_info: SelfInfo = .{
+        .allocator = allocator,
+        .address_map = std.AutoHashMap(usize, *Module).init(allocator),
+        .modules = if (native_os == .windows) .{} else {},
+    };
+
+    if (native_os == .windows) {
+        errdefer debug_info.modules.deinit(allocator);
+
+        const handle = windows.kernel32.CreateToolhelp32Snapshot(windows.TH32CS_SNAPMODULE | windows.TH32CS_SNAPMODULE32, 0);
+        if (handle == windows.INVALID_HANDLE_VALUE) {
+            switch (windows.GetLastError()) {
+                else => |err| return windows.unexpectedError(err),
+            }
+        }
+        defer windows.CloseHandle(handle);
+
+        var module_entry: windows.MODULEENTRY32 = undefined;
+        module_entry.dwSize = @sizeOf(windows.MODULEENTRY32);
+        if (windows.kernel32.Module32First(handle, &module_entry) == 0) {
+            return error.MissingDebugInfo;
+        }
+
+        var module_valid = true;
+        while (module_valid) {
+            const module_info = try debug_info.modules.addOne(allocator);
+            const name = allocator.dupe(u8, mem.sliceTo(&module_entry.szModule, 0)) catch &.{};
+            errdefer allocator.free(name);
+
+            module_info.* = .{
+                .base_address = @intFromPtr(module_entry.modBaseAddr),
+                .size = module_entry.modBaseSize,
+                .name = name,
+                .handle = module_entry.hModule,
+            };
+
+            module_valid = windows.kernel32.Module32Next(handle, &module_entry) == 1;
+        }
+    }
+
+    return debug_info;
+}
+
+pub fn deinit(self: *SelfInfo) void {
+    var it = self.address_map.iterator();
+    while (it.next()) |entry| {
+        const mdi = entry.value_ptr.*;
+        mdi.deinit(self.allocator);
+        self.allocator.destroy(mdi);
+    }
+    self.address_map.deinit();
+    if (native_os == .windows) {
+        for (self.modules.items) |module| {
+            self.allocator.free(module.name);
+            if (module.mapped_file) |mapped_file| mapped_file.deinit();
+        }
+        self.modules.deinit(self.allocator);
+    }
+}
+
+pub fn getModuleForAddress(self: *SelfInfo, address: usize) !*Module {
+    if (comptime builtin.target.isDarwin()) {
+        return self.lookupModuleDyld(address);
+    } else if (native_os == .windows) {
+        return self.lookupModuleWin32(address);
+    } else if (native_os == .haiku) {
+        return self.lookupModuleHaiku(address);
+    } else if (comptime builtin.target.isWasm()) {
+        return self.lookupModuleWasm(address);
+    } else {
+        return self.lookupModuleDl(address);
+    }
+}
+
+// Returns the module name for a given address.
+// This can be called when getModuleForAddress fails, so implementations should provide
+// a path that doesn't rely on any side-effects of a prior successful module lookup.
+pub fn getModuleNameForAddress(self: *SelfInfo, address: usize) ?[]const u8 {
+    if (comptime builtin.target.isDarwin()) {
+        return self.lookupModuleNameDyld(address);
+    } else if (native_os == .windows) {
+        return self.lookupModuleNameWin32(address);
+    } else if (native_os == .haiku) {
+        return null;
+    } else if (comptime builtin.target.isWasm()) {
+        return null;
+    } else {
+        return self.lookupModuleNameDl(address);
+    }
+}
+
+fn lookupModuleDyld(self: *SelfInfo, address: usize) !*Module {
+    const image_count = std.c._dyld_image_count();
+
+    var i: u32 = 0;
+    while (i < image_count) : (i += 1) {
+        const header = std.c._dyld_get_image_header(i) orelse continue;
+        const base_address = @intFromPtr(header);
+        if (address < base_address) continue;
+        const vmaddr_slide = std.c._dyld_get_image_vmaddr_slide(i);
+
+        var it = macho.LoadCommandIterator{
+            .ncmds = header.ncmds,
+            .buffer = @alignCast(@as(
+                [*]u8,
+                @ptrFromInt(@intFromPtr(header) + @sizeOf(macho.mach_header_64)),
+            )[0..header.sizeofcmds]),
+        };
+
+        var unwind_info: ?[]const u8 = null;
+        var eh_frame: ?[]const u8 = null;
+        while (it.next()) |cmd| switch (cmd.cmd()) {
+            .SEGMENT_64 => {
+                const segment_cmd = cmd.cast(macho.segment_command_64).?;
+                if (!mem.eql(u8, "__TEXT", segment_cmd.segName())) continue;
+
+                const seg_start = segment_cmd.vmaddr + vmaddr_slide;
+                const seg_end = seg_start + segment_cmd.vmsize;
+                if (address >= seg_start and address < seg_end) {
+                    if (self.address_map.get(base_address)) |obj_di| {
+                        return obj_di;
+                    }
+
+                    for (cmd.getSections()) |sect| {
+                        if (mem.eql(u8, "__unwind_info", sect.sectName())) {
+                            unwind_info = @as([*]const u8, @ptrFromInt(sect.addr + vmaddr_slide))[0..sect.size];
+                        } else if (mem.eql(u8, "__eh_frame", sect.sectName())) {
+                            eh_frame = @as([*]const u8, @ptrFromInt(sect.addr + vmaddr_slide))[0..sect.size];
+                        }
+                    }
+
+                    const obj_di = try self.allocator.create(Module);
+                    errdefer self.allocator.destroy(obj_di);
+
+                    const macho_path = mem.sliceTo(std.c._dyld_get_image_name(i), 0);
+                    const macho_file = fs.cwd().openFile(macho_path, .{}) catch |err| switch (err) {
+                        error.FileNotFound => return error.MissingDebugInfo,
+                        else => return err,
+                    };
+                    obj_di.* = try readMachODebugInfo(self.allocator, macho_file);
+                    obj_di.base_address = base_address;
+                    obj_di.vmaddr_slide = vmaddr_slide;
+                    obj_di.unwind_info = unwind_info;
+                    obj_di.eh_frame = eh_frame;
+
+                    try self.address_map.putNoClobber(base_address, obj_di);
+
+                    return obj_di;
+                }
+            },
+            else => {},
+        };
+    }
+
+    return error.MissingDebugInfo;
+}
+
+fn lookupModuleNameDyld(self: *SelfInfo, address: usize) ?[]const u8 {
+    _ = self;
+    const image_count = std.c._dyld_image_count();
+
+    var i: u32 = 0;
+    while (i < image_count) : (i += 1) {
+        const header = std.c._dyld_get_image_header(i) orelse continue;
+        const base_address = @intFromPtr(header);
+        if (address < base_address) continue;
+        const vmaddr_slide = std.c._dyld_get_image_vmaddr_slide(i);
+
+        var it = macho.LoadCommandIterator{
+            .ncmds = header.ncmds,
+            .buffer = @alignCast(@as(
+                [*]u8,
+                @ptrFromInt(@intFromPtr(header) + @sizeOf(macho.mach_header_64)),
+            )[0..header.sizeofcmds]),
+        };
+
+        while (it.next()) |cmd| switch (cmd.cmd()) {
+            .SEGMENT_64 => {
+                const segment_cmd = cmd.cast(macho.segment_command_64).?;
+                if (!mem.eql(u8, "__TEXT", segment_cmd.segName())) continue;
+
+                const original_address = address - vmaddr_slide;
+                const seg_start = segment_cmd.vmaddr;
+                const seg_end = seg_start + segment_cmd.vmsize;
+                if (original_address >= seg_start and original_address < seg_end) {
+                    return fs.path.basename(mem.sliceTo(std.c._dyld_get_image_name(i), 0));
+                }
+            },
+            else => {},
+        };
+    }
+
+    return null;
+}
+
+fn lookupModuleWin32(self: *SelfInfo, address: usize) !*Module {
+    for (self.modules.items) |*module| {
+        if (address >= module.base_address and address < module.base_address + module.size) {
+            if (self.address_map.get(module.base_address)) |obj_di| {
+                return obj_di;
+            }
+
+            const obj_di = try self.allocator.create(Module);
+            errdefer self.allocator.destroy(obj_di);
+
+            const mapped_module = @as([*]const u8, @ptrFromInt(module.base_address))[0..module.size];
+            var coff_obj = try coff.Coff.init(mapped_module, true);
+
+            // The string table is not mapped into memory by the loader, so if a section name is in the
+            // string table then we have to map the full image file from disk. This can happen when
+            // a binary is produced with -gdwarf, since the section names are longer than 8 bytes.
+            if (coff_obj.strtabRequired()) {
+                var name_buffer: [windows.PATH_MAX_WIDE + 4:0]u16 = undefined;
+                // openFileAbsoluteW requires the prefix to be present
+                @memcpy(name_buffer[0..4], &[_]u16{ '\\', '?', '?', '\\' });
+
+                const process_handle = windows.GetCurrentProcess();
+                const len = windows.kernel32.GetModuleFileNameExW(
+                    process_handle,
+                    module.handle,
+                    @ptrCast(&name_buffer[4]),
+                    windows.PATH_MAX_WIDE,
+                );
+
+                if (len == 0) return error.MissingDebugInfo;
+                const coff_file = fs.openFileAbsoluteW(name_buffer[0 .. len + 4 :0], .{}) catch |err| switch (err) {
+                    error.FileNotFound => return error.MissingDebugInfo,
+                    else => return err,
+                };
+                errdefer coff_file.close();
+
+                var section_handle: windows.HANDLE = undefined;
+                const create_section_rc = windows.ntdll.NtCreateSection(
+                    &section_handle,
+                    windows.STANDARD_RIGHTS_REQUIRED | windows.SECTION_QUERY | windows.SECTION_MAP_READ,
+                    null,
+                    null,
+                    windows.PAGE_READONLY,
+                    // The documentation states that if no AllocationAttribute is specified, then SEC_COMMIT is the default.
+                    // In practice, this isn't the case and specifying 0 will result in INVALID_PARAMETER_6.
+                    windows.SEC_COMMIT,
+                    coff_file.handle,
+                );
+                if (create_section_rc != .SUCCESS) return error.MissingDebugInfo;
+                errdefer windows.CloseHandle(section_handle);
+
+                var coff_len: usize = 0;
+                var base_ptr: usize = 0;
+                const map_section_rc = windows.ntdll.NtMapViewOfSection(
+                    section_handle,
+                    process_handle,
+                    @ptrCast(&base_ptr),
+                    null,
+                    0,
+                    null,
+                    &coff_len,
+                    .ViewUnmap,
+                    0,
+                    windows.PAGE_READONLY,
+                );
+                if (map_section_rc != .SUCCESS) return error.MissingDebugInfo;
+                errdefer assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @ptrFromInt(base_ptr)) == .SUCCESS);
+
+                const section_view = @as([*]const u8, @ptrFromInt(base_ptr))[0..coff_len];
+                coff_obj = try coff.Coff.init(section_view, false);
+
+                module.mapped_file = .{
+                    .file = coff_file,
+                    .section_handle = section_handle,
+                    .section_view = section_view,
+                };
+            }
+            errdefer if (module.mapped_file) |mapped_file| mapped_file.deinit();
+
+            obj_di.* = try readCoffDebugInfo(self.allocator, &coff_obj);
+            obj_di.base_address = module.base_address;
+
+            try self.address_map.putNoClobber(module.base_address, obj_di);
+            return obj_di;
+        }
+    }
+
+    return error.MissingDebugInfo;
+}
+
+fn lookupModuleNameWin32(self: *SelfInfo, address: usize) ?[]const u8 {
+    for (self.modules.items) |module| {
+        if (address >= module.base_address and address < module.base_address + module.size) {
+            return module.name;
+        }
+    }
+    return null;
+}
+
+fn lookupModuleNameDl(self: *SelfInfo, address: usize) ?[]const u8 {
+    _ = self;
+
+    var ctx: struct {
+        // Input
+        address: usize,
+        // Output
+        name: []const u8 = "",
+    } = .{ .address = address };
+    const CtxTy = @TypeOf(ctx);
+
+    if (posix.dl_iterate_phdr(&ctx, error{Found}, struct {
+        fn callback(info: *posix.dl_phdr_info, size: usize, context: *CtxTy) !void {
+            _ = size;
+            if (context.address < info.addr) return;
+            const phdrs = info.phdr[0..info.phnum];
+            for (phdrs) |*phdr| {
+                if (phdr.p_type != elf.PT_LOAD) continue;
+
+                const seg_start = info.addr +% phdr.p_vaddr;
+                const seg_end = seg_start + phdr.p_memsz;
+                if (context.address >= seg_start and context.address < seg_end) {
+                    context.name = mem.sliceTo(info.name, 0) orelse "";
+                    break;
+                }
+            } else return;
+
+            return error.Found;
+        }
+    }.callback)) {
+        return null;
+    } else |err| switch (err) {
+        error.Found => return fs.path.basename(ctx.name),
+    }
+
+    return null;
+}
+
+fn lookupModuleDl(self: *SelfInfo, address: usize) !*Module {
+    var ctx: struct {
+        // Input
+        address: usize,
+        // Output
+        base_address: usize = undefined,
+        name: []const u8 = undefined,
+        build_id: ?[]const u8 = null,
+        gnu_eh_frame: ?[]const u8 = null,
+    } = .{ .address = address };
+    const CtxTy = @TypeOf(ctx);
+
+    if (posix.dl_iterate_phdr(&ctx, error{Found}, struct {
+        fn callback(info: *posix.dl_phdr_info, size: usize, context: *CtxTy) !void {
+            _ = size;
+            // The base address is too high
+            if (context.address < info.addr)
+                return;
+
+            const phdrs = info.phdr[0..info.phnum];
+            for (phdrs) |*phdr| {
+                if (phdr.p_type != elf.PT_LOAD) continue;
+
+                // Overflowing addition is used to handle the case of VSDOs having a p_vaddr = 0xffffffffff700000
+                const seg_start = info.addr +% phdr.p_vaddr;
+                const seg_end = seg_start + phdr.p_memsz;
+                if (context.address >= seg_start and context.address < seg_end) {
+                    // Android libc uses NULL instead of an empty string to mark the
+                    // main program
+                    context.name = mem.sliceTo(info.name, 0) orelse "";
+                    context.base_address = info.addr;
+                    break;
+                }
+            } else return;
+
+            for (info.phdr[0..info.phnum]) |phdr| {
+                switch (phdr.p_type) {
+                    elf.PT_NOTE => {
+                        // Look for .note.gnu.build-id
+                        const note_bytes = @as([*]const u8, @ptrFromInt(info.addr + phdr.p_vaddr))[0..phdr.p_memsz];
+                        const name_size = mem.readInt(u32, note_bytes[0..4], native_endian);
+                        if (name_size != 4) continue;
+                        const desc_size = mem.readInt(u32, note_bytes[4..8], native_endian);
+                        const note_type = mem.readInt(u32, note_bytes[8..12], native_endian);
+                        if (note_type != elf.NT_GNU_BUILD_ID) continue;
+                        if (!mem.eql(u8, "GNU\x00", note_bytes[12..16])) continue;
+                        context.build_id = note_bytes[16..][0..desc_size];
+                    },
+                    elf.PT_GNU_EH_FRAME => {
+                        context.gnu_eh_frame = @as([*]const u8, @ptrFromInt(info.addr + phdr.p_vaddr))[0..phdr.p_memsz];
+                    },
+                    else => {},
+                }
+            }
+
+            // Stop the iteration
+            return error.Found;
+        }
+    }.callback)) {
+        return error.MissingDebugInfo;
+    } else |err| switch (err) {
+        error.Found => {},
+    }
+
+    if (self.address_map.get(ctx.base_address)) |obj_di| {
+        return obj_di;
+    }
+
+    const obj_di = try self.allocator.create(Module);
+    errdefer self.allocator.destroy(obj_di);
+
+    var sections: Dwarf.SectionArray = Dwarf.null_section_array;
+    if (ctx.gnu_eh_frame) |eh_frame_hdr| {
+        // This is a special case - pointer offsets inside .eh_frame_hdr
+        // are encoded relative to its base address, so we must use the
+        // version that is already memory mapped, and not the one that
+        // will be mapped separately from the ELF file.
+        sections[@intFromEnum(Dwarf.Section.Id.eh_frame_hdr)] = .{
+            .data = eh_frame_hdr,
+            .owned = false,
+        };
+    }
+
+    obj_di.* = try readElfDebugInfo(self.allocator, if (ctx.name.len > 0) ctx.name else null, ctx.build_id, null, &sections, null);
+    obj_di.base_address = ctx.base_address;
+
+    // Missing unwind info isn't treated as a failure, as the unwinder will fall back to FP-based unwinding
+    obj_di.dwarf.scanAllUnwindInfo(self.allocator, ctx.base_address) catch {};
+
+    try self.address_map.putNoClobber(ctx.base_address, obj_di);
+
+    return obj_di;
+}
+
+fn lookupModuleHaiku(self: *SelfInfo, address: usize) !*Module {
+    _ = self;
+    _ = address;
+    @panic("TODO implement lookup module for Haiku");
+}
+
+fn lookupModuleWasm(self: *SelfInfo, address: usize) !*Module {
+    _ = self;
+    _ = address;
+    @panic("TODO implement lookup module for Wasm");
+}
+
+pub const Module = switch (native_os) {
+    .macos, .ios, .watchos, .tvos, .visionos => struct {
+        base_address: usize,
+        vmaddr_slide: usize,
+        mapped_memory: []align(mem.page_size) const u8,
+        symbols: []const MachoSymbol,
+        strings: [:0]const u8,
+        ofiles: OFileTable,
+
+        // Backed by the in-memory sections mapped by the loader
+        unwind_info: ?[]const u8 = null,
+        eh_frame: ?[]const u8 = null,
+
+        const OFileTable = std.StringHashMap(OFileInfo);
+        const OFileInfo = struct {
+            di: Dwarf,
+            addr_table: std.StringHashMap(u64),
+        };
+
+        pub fn deinit(self: *@This(), allocator: Allocator) void {
+            var it = self.ofiles.iterator();
+            while (it.next()) |entry| {
+                const ofile = entry.value_ptr;
+                ofile.di.deinit(allocator);
+                ofile.addr_table.deinit();
+            }
+            self.ofiles.deinit();
+            allocator.free(self.symbols);
+            posix.munmap(self.mapped_memory);
+        }
+
+        fn loadOFile(self: *@This(), allocator: Allocator, o_file_path: []const u8) !*OFileInfo {
+            const o_file = try fs.cwd().openFile(o_file_path, .{});
+            const mapped_mem = try mapWholeFile(o_file);
+
+            const hdr: *const macho.mach_header_64 = @ptrCast(@alignCast(mapped_mem.ptr));
+            if (hdr.magic != std.macho.MH_MAGIC_64)
+                return error.InvalidDebugInfo;
+
+            var segcmd: ?macho.LoadCommandIterator.LoadCommand = null;
+            var symtabcmd: ?macho.symtab_command = null;
+            var it = macho.LoadCommandIterator{
+                .ncmds = hdr.ncmds,
+                .buffer = mapped_mem[@sizeOf(macho.mach_header_64)..][0..hdr.sizeofcmds],
+            };
+            while (it.next()) |cmd| switch (cmd.cmd()) {
+                .SEGMENT_64 => segcmd = cmd,
+                .SYMTAB => symtabcmd = cmd.cast(macho.symtab_command).?,
+                else => {},
+            };
+
+            if (segcmd == null or symtabcmd == null) return error.MissingDebugInfo;
+
+            // Parse symbols
+            const strtab = @as(
+                [*]const u8,
+                @ptrCast(&mapped_mem[symtabcmd.?.stroff]),
+            )[0 .. symtabcmd.?.strsize - 1 :0];
+            const symtab = @as(
+                [*]const macho.nlist_64,
+                @ptrCast(@alignCast(&mapped_mem[symtabcmd.?.symoff])),
+            )[0..symtabcmd.?.nsyms];
+
+            // TODO handle tentative (common) symbols
+            var addr_table = std.StringHashMap(u64).init(allocator);
+            try addr_table.ensureTotalCapacity(@as(u32, @intCast(symtab.len)));
+            for (symtab) |sym| {
+                if (sym.n_strx == 0) continue;
+                if (sym.undf() or sym.tentative() or sym.abs()) continue;
+                const sym_name = mem.sliceTo(strtab[sym.n_strx..], 0);
+                // TODO is it possible to have a symbol collision?
+                addr_table.putAssumeCapacityNoClobber(sym_name, sym.n_value);
+            }
+
+            var sections: Dwarf.SectionArray = Dwarf.null_section_array;
+            if (self.eh_frame) |eh_frame| sections[@intFromEnum(Dwarf.Section.Id.eh_frame)] = .{
+                .data = eh_frame,
+                .owned = false,
+            };
+
+            for (segcmd.?.getSections()) |sect| {
+                if (!std.mem.eql(u8, "__DWARF", sect.segName())) continue;
+
+                var section_index: ?usize = null;
+                inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
+                    if (mem.eql(u8, "__" ++ section.name, sect.sectName())) section_index = i;
+                }
+                if (section_index == null) continue;
+
+                const section_bytes = try chopSlice(mapped_mem, sect.offset, sect.size);
+                sections[section_index.?] = .{
+                    .data = section_bytes,
+                    .virtual_address = sect.addr,
+                    .owned = false,
+                };
+            }
+
+            const missing_debug_info =
+                sections[@intFromEnum(Dwarf.Section.Id.debug_info)] == null or
+                sections[@intFromEnum(Dwarf.Section.Id.debug_abbrev)] == null or
+                sections[@intFromEnum(Dwarf.Section.Id.debug_str)] == null or
+                sections[@intFromEnum(Dwarf.Section.Id.debug_line)] == null;
+            if (missing_debug_info) return error.MissingDebugInfo;
+
+            var di = Dwarf{
+                .endian = .little,
+                .sections = sections,
+                .is_macho = true,
+            };
+
+            try Dwarf.open(&di, allocator);
+            const info = OFileInfo{
+                .di = di,
+                .addr_table = addr_table,
+            };
+
+            // Add the debug info to the cache
+            const result = try self.ofiles.getOrPut(o_file_path);
+            assert(!result.found_existing);
+            result.value_ptr.* = info;
+
+            return result.value_ptr;
+        }
+
+        pub fn getSymbolAtAddress(self: *@This(), allocator: Allocator, address: usize) !SymbolInfo {
+            nosuspend {
+                const result = try self.getOFileInfoForAddress(allocator, address);
+                if (result.symbol == null) return .{};
+
+                // Take the symbol name from the N_FUN STAB entry, we're going to
+                // use it if we fail to find the DWARF infos
+                const stab_symbol = mem.sliceTo(self.strings[result.symbol.?.strx..], 0);
+                if (result.o_file_info == null) return .{ .symbol_name = stab_symbol };
+
+                // Translate again the address, this time into an address inside the
+                // .o file
+                const relocated_address_o = result.o_file_info.?.addr_table.get(stab_symbol) orelse return .{
+                    .symbol_name = "???",
+                };
+
+                const addr_off = result.relocated_address - result.symbol.?.addr;
+                const o_file_di = &result.o_file_info.?.di;
+                if (o_file_di.findCompileUnit(relocated_address_o)) |compile_unit| {
+                    return SymbolInfo{
+                        .symbol_name = o_file_di.getSymbolName(relocated_address_o) orelse "???",
+                        .compile_unit_name = compile_unit.die.getAttrString(
+                            o_file_di,
+                            std.dwarf.AT.name,
+                            o_file_di.section(.debug_str),
+                            compile_unit.*,
+                        ) catch |err| switch (err) {
+                            error.MissingDebugInfo, error.InvalidDebugInfo => "???",
+                        },
+                        .line_info = o_file_di.getLineNumberInfo(
+                            allocator,
+                            compile_unit.*,
+                            relocated_address_o + addr_off,
+                        ) catch |err| switch (err) {
+                            error.MissingDebugInfo, error.InvalidDebugInfo => null,
+                            else => return err,
+                        },
+                    };
+                } else |err| switch (err) {
+                    error.MissingDebugInfo, error.InvalidDebugInfo => {
+                        return SymbolInfo{ .symbol_name = stab_symbol };
+                    },
+                    else => return err,
+                }
+            }
+        }
+
+        pub fn getOFileInfoForAddress(self: *@This(), allocator: Allocator, address: usize) !struct {
+            relocated_address: usize,
+            symbol: ?*const MachoSymbol = null,
+            o_file_info: ?*OFileInfo = null,
+        } {
+            nosuspend {
+                // Translate the VA into an address into this object
+                const relocated_address = address - self.vmaddr_slide;
+
+                // Find the .o file where this symbol is defined
+                const symbol = machoSearchSymbols(self.symbols, relocated_address) orelse return .{
+                    .relocated_address = relocated_address,
+                };
+
+                // Check if its debug infos are already in the cache
+                const o_file_path = mem.sliceTo(self.strings[symbol.ofile..], 0);
+                const o_file_info = self.ofiles.getPtr(o_file_path) orelse
+                    (self.loadOFile(allocator, o_file_path) catch |err| switch (err) {
+                    error.FileNotFound,
+                    error.MissingDebugInfo,
+                    error.InvalidDebugInfo,
+                    => return .{
+                        .relocated_address = relocated_address,
+                        .symbol = symbol,
+                    },
+                    else => return err,
+                });
+
+                return .{
+                    .relocated_address = relocated_address,
+                    .symbol = symbol,
+                    .o_file_info = o_file_info,
+                };
+            }
+        }
+
+        pub fn getDwarfInfoForAddress(self: *@This(), allocator: Allocator, address: usize) !?*const Dwarf {
+            return if ((try self.getOFileInfoForAddress(allocator, address)).o_file_info) |o_file_info| &o_file_info.di else null;
+        }
+    },
+    .uefi, .windows => struct {
+        base_address: usize,
+        pdb: ?Pdb = null,
+        dwarf: ?Dwarf = null,
+        coff_image_base: u64,
+
+        /// Only used if pdb is non-null
+        coff_section_headers: []coff.SectionHeader,
+
+        pub fn deinit(self: *@This(), allocator: Allocator) void {
+            if (self.dwarf) |*dwarf| {
+                dwarf.deinit(allocator);
+            }
+
+            if (self.pdb) |*p| {
+                p.deinit();
+                allocator.free(self.coff_section_headers);
+            }
+        }
+
+        fn getSymbolFromPdb(self: *@This(), relocated_address: usize) !?SymbolInfo {
+            var coff_section: *align(1) const coff.SectionHeader = undefined;
+            const mod_index = for (self.pdb.?.sect_contribs) |sect_contrib| {
+                if (sect_contrib.Section > self.coff_section_headers.len) continue;
+                // Remember that SectionContribEntry.Section is 1-based.
+                coff_section = &self.coff_section_headers[sect_contrib.Section - 1];
+
+                const vaddr_start = coff_section.virtual_address + sect_contrib.Offset;
+                const vaddr_end = vaddr_start + sect_contrib.Size;
+                if (relocated_address >= vaddr_start and relocated_address < vaddr_end) {
+                    break sect_contrib.ModuleIndex;
+                }
+            } else {
+                // we have no information to add to the address
+                return null;
+            };
+
+            const module = (try self.pdb.?.getModule(mod_index)) orelse
+                return error.InvalidDebugInfo;
+            const obj_basename = fs.path.basename(module.obj_file_name);
+
+            const symbol_name = self.pdb.?.getSymbolName(
+                module,
+                relocated_address - coff_section.virtual_address,
+            ) orelse "???";
+            const opt_line_info = try self.pdb.?.getLineNumberInfo(
+                module,
+                relocated_address - coff_section.virtual_address,
+            );
+
+            return SymbolInfo{
+                .symbol_name = symbol_name,
+                .compile_unit_name = obj_basename,
+                .line_info = opt_line_info,
+            };
+        }
+
+        pub fn getSymbolAtAddress(self: *@This(), allocator: Allocator, address: usize) !SymbolInfo {
+            // Translate the VA into an address into this object
+            const relocated_address = address - self.base_address;
+
+            if (self.pdb != null) {
+                if (try self.getSymbolFromPdb(relocated_address)) |symbol| return symbol;
+            }
+
+            if (self.dwarf) |*dwarf| {
+                const dwarf_address = relocated_address + self.coff_image_base;
+                return getSymbolFromDwarf(allocator, dwarf_address, dwarf);
+            }
+
+            return SymbolInfo{};
+        }
+
+        pub fn getDwarfInfoForAddress(self: *@This(), allocator: Allocator, address: usize) !?*const Dwarf {
+            _ = allocator;
+            _ = address;
+
+            return switch (self.debug_data) {
+                .dwarf => |*dwarf| dwarf,
+                else => null,
+            };
+        }
+    },
+    .linux, .netbsd, .freebsd, .dragonfly, .openbsd, .haiku, .solaris, .illumos => struct {
+        base_address: usize,
+        dwarf: Dwarf,
+        mapped_memory: []align(mem.page_size) const u8,
+        external_mapped_memory: ?[]align(mem.page_size) const u8,
+
+        pub fn deinit(self: *@This(), allocator: Allocator) void {
+            self.dwarf.deinit(allocator);
+            posix.munmap(self.mapped_memory);
+            if (self.external_mapped_memory) |m| posix.munmap(m);
+        }
+
+        pub fn getSymbolAtAddress(self: *@This(), allocator: Allocator, address: usize) !SymbolInfo {
+            // Translate the VA into an address into this object
+            const relocated_address = address - self.base_address;
+            return getSymbolFromDwarf(allocator, relocated_address, &self.dwarf);
+        }
+
+        pub fn getDwarfInfoForAddress(self: *@This(), allocator: Allocator, address: usize) !?*const Dwarf {
+            _ = allocator;
+            _ = address;
+            return &self.dwarf;
+        }
+    },
+    .wasi, .emscripten => struct {
+        pub fn deinit(self: *@This(), allocator: Allocator) void {
+            _ = self;
+            _ = allocator;
+        }
+
+        pub fn getSymbolAtAddress(self: *@This(), allocator: Allocator, address: usize) !SymbolInfo {
+            _ = self;
+            _ = allocator;
+            _ = address;
+            return SymbolInfo{};
+        }
+
+        pub fn getDwarfInfoForAddress(self: *@This(), allocator: Allocator, address: usize) !?*const Dwarf {
+            _ = self;
+            _ = allocator;
+            _ = address;
+            return null;
+        }
+    },
+    else => Dwarf,
+};
+
+/// How is this different than `Module` when the host is Windows?
+/// Why are both stored in the `SelfInfo` struct?
+/// Boy, it sure would be nice if someone added documentation comments for this
+/// struct explaining it.
+pub const WindowsModule = struct {
+    base_address: usize,
+    size: u32,
+    name: []const u8,
+    handle: windows.HMODULE,
+
+    // Set when the image file needed to be mapped from disk
+    mapped_file: ?struct {
+        file: File,
+        section_handle: windows.HANDLE,
+        section_view: []const u8,
+
+        pub fn deinit(self: @This()) void {
+            const process_handle = windows.GetCurrentProcess();
+            assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @constCast(@ptrCast(self.section_view.ptr))) == .SUCCESS);
+            windows.CloseHandle(self.section_handle);
+            self.file.close();
+        }
+    } = null,
+};
+
+/// This takes ownership of macho_file: users of this function should not close
+/// it themselves, even on error.
+/// TODO it's weird to take ownership even on error, rework this code.
+fn readMachODebugInfo(allocator: Allocator, macho_file: File) !Module {
+    const mapped_mem = try mapWholeFile(macho_file);
+
+    const hdr: *const macho.mach_header_64 = @ptrCast(@alignCast(mapped_mem.ptr));
+    if (hdr.magic != macho.MH_MAGIC_64)
+        return error.InvalidDebugInfo;
+
+    var it = macho.LoadCommandIterator{
+        .ncmds = hdr.ncmds,
+        .buffer = mapped_mem[@sizeOf(macho.mach_header_64)..][0..hdr.sizeofcmds],
+    };
+    const symtab = while (it.next()) |cmd| switch (cmd.cmd()) {
+        .SYMTAB => break cmd.cast(macho.symtab_command).?,
+        else => {},
+    } else return error.MissingDebugInfo;
+
+    const syms = @as(
+        [*]const macho.nlist_64,
+        @ptrCast(@alignCast(&mapped_mem[symtab.symoff])),
+    )[0..symtab.nsyms];
+    const strings = mapped_mem[symtab.stroff..][0 .. symtab.strsize - 1 :0];
+
+    const symbols_buf = try allocator.alloc(MachoSymbol, syms.len);
+
+    var ofile: u32 = undefined;
+    var last_sym: MachoSymbol = undefined;
+    var symbol_index: usize = 0;
+    var state: enum {
+        init,
+        oso_open,
+        oso_close,
+        bnsym,
+        fun_strx,
+        fun_size,
+        ensym,
+    } = .init;
+
+    for (syms) |*sym| {
+        if (!sym.stab()) continue;
+
+        // TODO handle globals N_GSYM, and statics N_STSYM
+        switch (sym.n_type) {
+            macho.N_OSO => {
+                switch (state) {
+                    .init, .oso_close => {
+                        state = .oso_open;
+                        ofile = sym.n_strx;
+                    },
+                    else => return error.InvalidDebugInfo,
+                }
+            },
+            macho.N_BNSYM => {
+                switch (state) {
+                    .oso_open, .ensym => {
+                        state = .bnsym;
+                        last_sym = .{
+                            .strx = 0,
+                            .addr = sym.n_value,
+                            .size = 0,
+                            .ofile = ofile,
+                        };
+                    },
+                    else => return error.InvalidDebugInfo,
+                }
+            },
+            macho.N_FUN => {
+                switch (state) {
+                    .bnsym => {
+                        state = .fun_strx;
+                        last_sym.strx = sym.n_strx;
+                    },
+                    .fun_strx => {
+                        state = .fun_size;
+                        last_sym.size = @as(u32, @intCast(sym.n_value));
+                    },
+                    else => return error.InvalidDebugInfo,
+                }
+            },
+            macho.N_ENSYM => {
+                switch (state) {
+                    .fun_size => {
+                        state = .ensym;
+                        symbols_buf[symbol_index] = last_sym;
+                        symbol_index += 1;
+                    },
+                    else => return error.InvalidDebugInfo,
+                }
+            },
+            macho.N_SO => {
+                switch (state) {
+                    .init, .oso_close => {},
+                    .oso_open, .ensym => {
+                        state = .oso_close;
+                    },
+                    else => return error.InvalidDebugInfo,
+                }
+            },
+            else => {},
+        }
+    }
+
+    switch (state) {
+        .init => return error.MissingDebugInfo,
+        .oso_close => {},
+        else => return error.InvalidDebugInfo,
+    }
+
+    const symbols = try allocator.realloc(symbols_buf, symbol_index);
+
+    // Even though lld emits symbols in ascending order, this debug code
+    // should work for programs linked in any valid way.
+    // This sort is so that we can binary search later.
+    mem.sort(MachoSymbol, symbols, {}, MachoSymbol.addressLessThan);
+
+    return .{
+        .base_address = undefined,
+        .vmaddr_slide = undefined,
+        .mapped_memory = mapped_mem,
+        .ofiles = Module.OFileTable.init(allocator),
+        .symbols = symbols,
+        .strings = strings,
+    };
+}
+
+fn readCoffDebugInfo(allocator: Allocator, coff_obj: *coff.Coff) !Module {
+    nosuspend {
+        var di: Module = .{
+            .base_address = undefined,
+            .coff_image_base = coff_obj.getImageBase(),
+            .coff_section_headers = undefined,
+        };
+
+        if (coff_obj.getSectionByName(".debug_info")) |_| {
+            // This coff file has embedded DWARF debug info
+            var sections: Dwarf.SectionArray = Dwarf.null_section_array;
+            errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
+
+            inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
+                sections[i] = if (coff_obj.getSectionByName("." ++ section.name)) |section_header| blk: {
+                    break :blk .{
+                        .data = try coff_obj.getSectionDataAlloc(section_header, allocator),
+                        .virtual_address = section_header.virtual_address,
+                        .owned = true,
+                    };
+                } else null;
+            }
+
+            var dwarf = Dwarf{
+                .endian = native_endian,
+                .sections = sections,
+                .is_macho = false,
+            };
+
+            try Dwarf.open(&dwarf, allocator);
+            di.dwarf = dwarf;
+        }
+
+        const raw_path = try coff_obj.getPdbPath() orelse return di;
+        const path = blk: {
+            if (fs.path.isAbsolute(raw_path)) {
+                break :blk raw_path;
+            } else {
+                const self_dir = try fs.selfExeDirPathAlloc(allocator);
+                defer allocator.free(self_dir);
+                break :blk try fs.path.join(allocator, &.{ self_dir, raw_path });
+            }
+        };
+        defer if (path.ptr != raw_path.ptr) allocator.free(path);
+
+        di.pdb = Pdb.init(allocator, path) catch |err| switch (err) {
+            error.FileNotFound, error.IsDir => {
+                if (di.dwarf == null) return error.MissingDebugInfo;
+                return di;
+            },
+            else => return err,
+        };
+        try di.pdb.?.parseInfoStream();
+        try di.pdb.?.parseDbiStream();
+
+        if (!mem.eql(u8, &coff_obj.guid, &di.pdb.?.guid) or coff_obj.age != di.pdb.?.age)
+            return error.InvalidDebugInfo;
+
+        // Only used by the pdb path
+        di.coff_section_headers = try coff_obj.getSectionHeadersAlloc(allocator);
+        errdefer allocator.free(di.coff_section_headers);
+
+        return di;
+    }
+}
+
+/// Reads debug info from an ELF file, or the current binary if none in specified.
+/// If the required sections aren't present but a reference to external debug info is,
+/// then this this function will recurse to attempt to load the debug sections from
+/// an external file.
+pub fn readElfDebugInfo(
+    allocator: Allocator,
+    elf_filename: ?[]const u8,
+    build_id: ?[]const u8,
+    expected_crc: ?u32,
+    parent_sections: *Dwarf.SectionArray,
+    parent_mapped_mem: ?[]align(mem.page_size) const u8,
+) !Module {
+    nosuspend {
+        const elf_file = (if (elf_filename) |filename| blk: {
+            break :blk fs.cwd().openFile(filename, .{});
+        } else fs.openSelfExe(.{})) catch |err| switch (err) {
+            error.FileNotFound => return error.MissingDebugInfo,
+            else => return err,
+        };
+
+        const mapped_mem = try mapWholeFile(elf_file);
+        if (expected_crc) |crc| if (crc != std.hash.crc.Crc32.hash(mapped_mem)) return error.InvalidDebugInfo;
+
+        const hdr: *const elf.Ehdr = @ptrCast(&mapped_mem[0]);
+        if (!mem.eql(u8, hdr.e_ident[0..4], elf.MAGIC)) return error.InvalidElfMagic;
+        if (hdr.e_ident[elf.EI_VERSION] != 1) return error.InvalidElfVersion;
+
+        const endian: std.builtin.Endian = switch (hdr.e_ident[elf.EI_DATA]) {
+            elf.ELFDATA2LSB => .little,
+            elf.ELFDATA2MSB => .big,
+            else => return error.InvalidElfEndian,
+        };
+        assert(endian == native_endian); // this is our own debug info
+
+        const shoff = hdr.e_shoff;
+        const str_section_off = shoff + @as(u64, hdr.e_shentsize) * @as(u64, hdr.e_shstrndx);
+        const str_shdr: *const elf.Shdr = @ptrCast(@alignCast(&mapped_mem[math.cast(usize, str_section_off) orelse return error.Overflow]));
+        const header_strings = mapped_mem[str_shdr.sh_offset..][0..str_shdr.sh_size];
+        const shdrs = @as(
+            [*]const elf.Shdr,
+            @ptrCast(@alignCast(&mapped_mem[shoff])),
+        )[0..hdr.e_shnum];
+
+        var sections: Dwarf.SectionArray = Dwarf.null_section_array;
+
+        // Combine section list. This takes ownership over any owned sections from the parent scope.
+        for (parent_sections, &sections) |*parent, *section| {
+            if (parent.*) |*p| {
+                section.* = p.*;
+                p.owned = false;
+            }
+        }
+        errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
+
+        var separate_debug_filename: ?[]const u8 = null;
+        var separate_debug_crc: ?u32 = null;
+
+        for (shdrs) |*shdr| {
+            if (shdr.sh_type == elf.SHT_NULL or shdr.sh_type == elf.SHT_NOBITS) continue;
+            const name = mem.sliceTo(header_strings[shdr.sh_name..], 0);
+
+            if (mem.eql(u8, name, ".gnu_debuglink")) {
+                const gnu_debuglink = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
+                const debug_filename = mem.sliceTo(@as([*:0]const u8, @ptrCast(gnu_debuglink.ptr)), 0);
+                const crc_offset = mem.alignForward(usize, @intFromPtr(&debug_filename[debug_filename.len]) + 1, 4) - @intFromPtr(gnu_debuglink.ptr);
+                const crc_bytes = gnu_debuglink[crc_offset..][0..4];
+                separate_debug_crc = mem.readInt(u32, crc_bytes, native_endian);
+                separate_debug_filename = debug_filename;
+                continue;
+            }
+
+            var section_index: ?usize = null;
+            inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
+                if (mem.eql(u8, "." ++ section.name, name)) section_index = i;
+            }
+            if (section_index == null) continue;
+            if (sections[section_index.?] != null) continue;
+
+            const section_bytes = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
+            sections[section_index.?] = if ((shdr.sh_flags & elf.SHF_COMPRESSED) > 0) blk: {
+                var section_stream = std.io.fixedBufferStream(section_bytes);
+                var section_reader = section_stream.reader();
+                const chdr = section_reader.readStruct(elf.Chdr) catch continue;
+                if (chdr.ch_type != .ZLIB) continue;
+
+                var zlib_stream = std.compress.zlib.decompressor(section_stream.reader());
+
+                const decompressed_section = try allocator.alloc(u8, chdr.ch_size);
+                errdefer allocator.free(decompressed_section);
+
+                const read = zlib_stream.reader().readAll(decompressed_section) catch continue;
+                assert(read == decompressed_section.len);
+
+                break :blk .{
+                    .data = decompressed_section,
+                    .virtual_address = shdr.sh_addr,
+                    .owned = true,
+                };
+            } else .{
+                .data = section_bytes,
+                .virtual_address = shdr.sh_addr,
+                .owned = false,
+            };
+        }
+
+        const missing_debug_info =
+            sections[@intFromEnum(Dwarf.Section.Id.debug_info)] == null or
+            sections[@intFromEnum(Dwarf.Section.Id.debug_abbrev)] == null or
+            sections[@intFromEnum(Dwarf.Section.Id.debug_str)] == null or
+            sections[@intFromEnum(Dwarf.Section.Id.debug_line)] == null;
+
+        // Attempt to load debug info from an external file
+        // See: https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
+        if (missing_debug_info) {
+
+            // Only allow one level of debug info nesting
+            if (parent_mapped_mem) |_| {
+                return error.MissingDebugInfo;
+            }
+
+            const global_debug_directories = [_][]const u8{
+                "/usr/lib/debug",
+            };
+
+            // <global debug directory>/.build-id/<2-character id prefix>/<id remainder>.debug
+            if (build_id) |id| blk: {
+                if (id.len < 3) break :blk;
+
+                // Either md5 (16 bytes) or sha1 (20 bytes) are used here in practice
+                const extension = ".debug";
+                var id_prefix_buf: [2]u8 = undefined;
+                var filename_buf: [38 + extension.len]u8 = undefined;
+
+                _ = std.fmt.bufPrint(&id_prefix_buf, "{s}", .{std.fmt.fmtSliceHexLower(id[0..1])}) catch unreachable;
+                const filename = std.fmt.bufPrint(
+                    &filename_buf,
+                    "{s}" ++ extension,
+                    .{std.fmt.fmtSliceHexLower(id[1..])},
+                ) catch break :blk;
+
+                for (global_debug_directories) |global_directory| {
+                    const path = try fs.path.join(allocator, &.{ global_directory, ".build-id", &id_prefix_buf, filename });
+                    defer allocator.free(path);
+
+                    return readElfDebugInfo(allocator, path, null, separate_debug_crc, &sections, mapped_mem) catch continue;
+                }
+            }
+
+            // use the path from .gnu_debuglink, in the same search order as gdb
+            if (separate_debug_filename) |separate_filename| blk: {
+                if (elf_filename != null and mem.eql(u8, elf_filename.?, separate_filename)) return error.MissingDebugInfo;
+
+                // <cwd>/<gnu_debuglink>
+                if (readElfDebugInfo(allocator, separate_filename, null, separate_debug_crc, &sections, mapped_mem)) |debug_info| return debug_info else |_| {}
+
+                // <cwd>/.debug/<gnu_debuglink>
+                {
+                    const path = try fs.path.join(allocator, &.{ ".debug", separate_filename });
+                    defer allocator.free(path);
+
+                    if (readElfDebugInfo(allocator, path, null, separate_debug_crc, &sections, mapped_mem)) |debug_info| return debug_info else |_| {}
+                }
+
+                var cwd_buf: [fs.max_path_bytes]u8 = undefined;
+                const cwd_path = posix.realpath(".", &cwd_buf) catch break :blk;
+
+                // <global debug directory>/<absolute folder of current binary>/<gnu_debuglink>
+                for (global_debug_directories) |global_directory| {
+                    const path = try fs.path.join(allocator, &.{ global_directory, cwd_path, separate_filename });
+                    defer allocator.free(path);
+                    if (readElfDebugInfo(allocator, path, null, separate_debug_crc, &sections, mapped_mem)) |debug_info| return debug_info else |_| {}
+                }
+            }
+
+            return error.MissingDebugInfo;
+        }
+
+        var di = Dwarf{
+            .endian = endian,
+            .sections = sections,
+            .is_macho = false,
+        };
+
+        try Dwarf.open(&di, allocator);
+
+        return .{
+            .base_address = undefined,
+            .dwarf = di,
+            .mapped_memory = parent_mapped_mem orelse mapped_mem,
+            .external_mapped_memory = if (parent_mapped_mem != null) mapped_mem else null,
+        };
+    }
+}
+
+const MachoSymbol = struct {
+    strx: u32,
+    addr: u64,
+    size: u32,
+    ofile: u32,
+
+    /// Returns the address from the macho file
+    fn address(self: MachoSymbol) u64 {
+        return self.addr;
+    }
+
+    fn addressLessThan(context: void, lhs: MachoSymbol, rhs: MachoSymbol) bool {
+        _ = context;
+        return lhs.addr < rhs.addr;
+    }
+};
+
+/// Takes ownership of file, even on error.
+/// TODO it's weird to take ownership even on error, rework this code.
+fn mapWholeFile(file: File) ![]align(mem.page_size) const u8 {
+    nosuspend {
+        defer file.close();
+
+        const file_len = math.cast(usize, try file.getEndPos()) orelse math.maxInt(usize);
+        const mapped_mem = try posix.mmap(
+            null,
+            file_len,
+            posix.PROT.READ,
+            .{ .TYPE = .SHARED },
+            file.handle,
+            0,
+        );
+        errdefer posix.munmap(mapped_mem);
+
+        return mapped_mem;
+    }
+}
+
+fn chopSlice(ptr: []const u8, offset: u64, size: u64) error{Overflow}![]const u8 {
+    const start = math.cast(usize, offset) orelse return error.Overflow;
+    const end = start + (math.cast(usize, size) orelse return error.Overflow);
+    return ptr[start..end];
+}
+
+pub const SymbolInfo = struct {
+    symbol_name: []const u8 = "???",
+    compile_unit_name: []const u8 = "???",
+    line_info: ?std.debug.SourceLocation = null,
+
+    pub fn deinit(self: SymbolInfo, allocator: Allocator) void {
+        if (self.line_info) |li| allocator.free(li.file_name);
+    }
+};
+
+fn machoSearchSymbols(symbols: []const MachoSymbol, address: usize) ?*const MachoSymbol {
+    var min: usize = 0;
+    var max: usize = symbols.len - 1;
+    while (min < max) {
+        const mid = min + (max - min) / 2;
+        const curr = &symbols[mid];
+        const next = &symbols[mid + 1];
+        if (address >= next.address()) {
+            min = mid + 1;
+        } else if (address < curr.address()) {
+            max = mid;
+        } else {
+            return curr;
+        }
+    }
+
+    const max_sym = &symbols[symbols.len - 1];
+    if (address >= max_sym.address())
+        return max_sym;
+
+    return null;
+}
+
+test machoSearchSymbols {
+    const symbols = [_]MachoSymbol{
+        .{ .addr = 100, .strx = undefined, .size = undefined, .ofile = undefined },
+        .{ .addr = 200, .strx = undefined, .size = undefined, .ofile = undefined },
+        .{ .addr = 300, .strx = undefined, .size = undefined, .ofile = undefined },
+    };
+
+    try testing.expectEqual(null, machoSearchSymbols(&symbols, 0));
+    try testing.expectEqual(null, machoSearchSymbols(&symbols, 99));
+    try testing.expectEqual(&symbols[0], machoSearchSymbols(&symbols, 100).?);
+    try testing.expectEqual(&symbols[0], machoSearchSymbols(&symbols, 150).?);
+    try testing.expectEqual(&symbols[0], machoSearchSymbols(&symbols, 199).?);
+
+    try testing.expectEqual(&symbols[1], machoSearchSymbols(&symbols, 200).?);
+    try testing.expectEqual(&symbols[1], machoSearchSymbols(&symbols, 250).?);
+    try testing.expectEqual(&symbols[1], machoSearchSymbols(&symbols, 299).?);
+
+    try testing.expectEqual(&symbols[2], machoSearchSymbols(&symbols, 300).?);
+    try testing.expectEqual(&symbols[2], machoSearchSymbols(&symbols, 301).?);
+    try testing.expectEqual(&symbols[2], machoSearchSymbols(&symbols, 5000).?);
+}
+
+fn getSymbolFromDwarf(allocator: Allocator, address: u64, di: *Dwarf) !SymbolInfo {
+    if (nosuspend di.findCompileUnit(address)) |compile_unit| {
+        return SymbolInfo{
+            .symbol_name = nosuspend di.getSymbolName(address) orelse "???",
+            .compile_unit_name = compile_unit.die.getAttrString(di, std.dwarf.AT.name, di.section(.debug_str), compile_unit.*) catch |err| switch (err) {
+                error.MissingDebugInfo, error.InvalidDebugInfo => "???",
+            },
+            .line_info = nosuspend di.getLineNumberInfo(allocator, compile_unit.*, address) catch |err| switch (err) {
+                error.MissingDebugInfo, error.InvalidDebugInfo => null,
+                else => return err,
+            },
+        };
+    } else |err| switch (err) {
+        error.MissingDebugInfo, error.InvalidDebugInfo => {
+            return SymbolInfo{};
+        },
+        else => return err,
+    }
+}
+
+/// Unwind a frame using MachO compact unwind info (from __unwind_info).
+/// If the compact encoding can't encode a way to unwind a frame, it will
+/// defer unwinding to DWARF, in which case `.eh_frame` will be used if available.
+pub fn unwindFrameMachO(
+    context: *UnwindContext,
+    ma: *std.debug.MemoryAccessor,
+    unwind_info: []const u8,
+    eh_frame: ?[]const u8,
+    module_base_address: usize,
+) !usize {
+    const header = std.mem.bytesAsValue(
+        macho.unwind_info_section_header,
+        unwind_info[0..@sizeOf(macho.unwind_info_section_header)],
+    );
+    const indices = std.mem.bytesAsSlice(
+        macho.unwind_info_section_header_index_entry,
+        unwind_info[header.indexSectionOffset..][0 .. header.indexCount * @sizeOf(macho.unwind_info_section_header_index_entry)],
+    );
+    if (indices.len == 0) return error.MissingUnwindInfo;
+
+    const mapped_pc = context.pc - module_base_address;
+    const second_level_index = blk: {
+        var left: usize = 0;
+        var len: usize = indices.len;
+
+        while (len > 1) {
+            const mid = left + len / 2;
+            const offset = indices[mid].functionOffset;
+            if (mapped_pc < offset) {
+                len /= 2;
+            } else {
+                left = mid;
+                if (mapped_pc == offset) break;
+                len -= len / 2;
+            }
+        }
+
+        // Last index is a sentinel containing the highest address as its functionOffset
+        if (indices[left].secondLevelPagesSectionOffset == 0) return error.MissingUnwindInfo;
+        break :blk &indices[left];
+    };
+
+    const common_encodings = std.mem.bytesAsSlice(
+        macho.compact_unwind_encoding_t,
+        unwind_info[header.commonEncodingsArraySectionOffset..][0 .. header.commonEncodingsArrayCount * @sizeOf(macho.compact_unwind_encoding_t)],
+    );
+
+    const start_offset = second_level_index.secondLevelPagesSectionOffset;
+    const kind = std.mem.bytesAsValue(
+        macho.UNWIND_SECOND_LEVEL,
+        unwind_info[start_offset..][0..@sizeOf(macho.UNWIND_SECOND_LEVEL)],
+    );
+
+    const entry: struct {
+        function_offset: usize,
+        raw_encoding: u32,
+    } = switch (kind.*) {
+        .REGULAR => blk: {
+            const page_header = std.mem.bytesAsValue(
+                macho.unwind_info_regular_second_level_page_header,
+                unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_regular_second_level_page_header)],
+            );
+
+            const entries = std.mem.bytesAsSlice(
+                macho.unwind_info_regular_second_level_entry,
+                unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.unwind_info_regular_second_level_entry)],
+            );
+            if (entries.len == 0) return error.InvalidUnwindInfo;
+
+            var left: usize = 0;
+            var len: usize = entries.len;
+            while (len > 1) {
+                const mid = left + len / 2;
+                const offset = entries[mid].functionOffset;
+                if (mapped_pc < offset) {
+                    len /= 2;
+                } else {
+                    left = mid;
+                    if (mapped_pc == offset) break;
+                    len -= len / 2;
+                }
+            }
+
+            break :blk .{
+                .function_offset = entries[left].functionOffset,
+                .raw_encoding = entries[left].encoding,
+            };
+        },
+        .COMPRESSED => blk: {
+            const page_header = std.mem.bytesAsValue(
+                macho.unwind_info_compressed_second_level_page_header,
+                unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_compressed_second_level_page_header)],
+            );
+
+            const entries = std.mem.bytesAsSlice(
+                macho.UnwindInfoCompressedEntry,
+                unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.UnwindInfoCompressedEntry)],
+            );
+            if (entries.len == 0) return error.InvalidUnwindInfo;
+
+            var left: usize = 0;
+            var len: usize = entries.len;
+            while (len > 1) {
+                const mid = left + len / 2;
+                const offset = second_level_index.functionOffset + entries[mid].funcOffset;
+                if (mapped_pc < offset) {
+                    len /= 2;
+                } else {
+                    left = mid;
+                    if (mapped_pc == offset) break;
+                    len -= len / 2;
+                }
+            }
+
+            const entry = entries[left];
+            const function_offset = second_level_index.functionOffset + entry.funcOffset;
+            if (entry.encodingIndex < header.commonEncodingsArrayCount) {
+                if (entry.encodingIndex >= common_encodings.len) return error.InvalidUnwindInfo;
+                break :blk .{
+                    .function_offset = function_offset,
+                    .raw_encoding = common_encodings[entry.encodingIndex],
+                };
+            } else {
+                const local_index = try math.sub(
+                    u8,
+                    entry.encodingIndex,
+                    math.cast(u8, header.commonEncodingsArrayCount) orelse return error.InvalidUnwindInfo,
+                );
+                const local_encodings = std.mem.bytesAsSlice(
+                    macho.compact_unwind_encoding_t,
+                    unwind_info[start_offset + page_header.encodingsPageOffset ..][0 .. page_header.encodingsCount * @sizeOf(macho.compact_unwind_encoding_t)],
+                );
+                if (local_index >= local_encodings.len) return error.InvalidUnwindInfo;
+                break :blk .{
+                    .function_offset = function_offset,
+                    .raw_encoding = local_encodings[local_index],
+                };
+            }
+        },
+        else => return error.InvalidUnwindInfo,
+    };
+
+    if (entry.raw_encoding == 0) return error.NoUnwindInfo;
+    const reg_context = Dwarf.abi.RegisterContext{
+        .eh_frame = false,
+        .is_macho = true,
+    };
+
+    const encoding: macho.CompactUnwindEncoding = @bitCast(entry.raw_encoding);
+    const new_ip = switch (builtin.cpu.arch) {
+        .x86_64 => switch (encoding.mode.x86_64) {
+            .OLD => return error.UnimplementedUnwindEncoding,
+            .RBP_FRAME => blk: {
+                const regs: [5]u3 = .{
+                    encoding.value.x86_64.frame.reg0,
+                    encoding.value.x86_64.frame.reg1,
+                    encoding.value.x86_64.frame.reg2,
+                    encoding.value.x86_64.frame.reg3,
+                    encoding.value.x86_64.frame.reg4,
+                };
+
+                const frame_offset = encoding.value.x86_64.frame.frame_offset * @sizeOf(usize);
+                var max_reg: usize = 0;
+                inline for (regs, 0..) |reg, i| {
+                    if (reg > 0) max_reg = i;
+                }
+
+                const fp = (try regValueNative(context.thread_context, fpRegNum(reg_context), reg_context)).*;
+                const new_sp = fp + 2 * @sizeOf(usize);
+
+                // Verify the stack range we're about to read register values from
+                if (ma.load(usize, new_sp) == null or ma.load(usize, fp - frame_offset + max_reg * @sizeOf(usize)) == null) return error.InvalidUnwindInfo;
+
+                const ip_ptr = fp + @sizeOf(usize);
+                const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+                const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
+
+                (try regValueNative(context.thread_context, fpRegNum(reg_context), reg_context)).* = new_fp;
+                (try regValueNative(context.thread_context, spRegNum(reg_context), reg_context)).* = new_sp;
+                (try regValueNative(context.thread_context, ip_reg_num, reg_context)).* = new_ip;
+
+                for (regs, 0..) |reg, i| {
+                    if (reg == 0) continue;
+                    const addr = fp - frame_offset + i * @sizeOf(usize);
+                    const reg_number = try Dwarf.compactUnwindToDwarfRegNumber(reg);
+                    (try regValueNative(context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(addr)).*;
+                }
+
+                break :blk new_ip;
+            },
+            .STACK_IMMD,
+            .STACK_IND,
+            => blk: {
+                const sp = (try regValueNative(context.thread_context, spRegNum(reg_context), reg_context)).*;
+                const stack_size = if (encoding.mode.x86_64 == .STACK_IMMD)
+                    @as(usize, encoding.value.x86_64.frameless.stack.direct.stack_size) * @sizeOf(usize)
+                else stack_size: {
+                    // In .STACK_IND, the stack size is inferred from the subq instruction at the beginning of the function.
+                    const sub_offset_addr =
+                        module_base_address +
+                        entry.function_offset +
+                        encoding.value.x86_64.frameless.stack.indirect.sub_offset;
+                    if (ma.load(usize, sub_offset_addr) == null) return error.InvalidUnwindInfo;
+
+                    // `sub_offset_addr` points to the offset of the literal within the instruction
+                    const sub_operand = @as(*align(1) const u32, @ptrFromInt(sub_offset_addr)).*;
+                    break :stack_size sub_operand + @sizeOf(usize) * @as(usize, encoding.value.x86_64.frameless.stack.indirect.stack_adjust);
+                };
+
+                // Decode the Lehmer-coded sequence of registers.
+                // For a description of the encoding see lib/libc/include/any-macos.13-any/mach-o/compact_unwind_encoding.h
+
+                // Decode the variable-based permutation number into its digits. Each digit represents
+                // an index into the list of register numbers that weren't yet used in the sequence at
+                // the time the digit was added.
+                const reg_count = encoding.value.x86_64.frameless.stack_reg_count;
+                const ip_ptr = if (reg_count > 0) reg_blk: {
+                    var digits: [6]u3 = undefined;
+                    var accumulator: usize = encoding.value.x86_64.frameless.stack_reg_permutation;
+                    var base: usize = 2;
+                    for (0..reg_count) |i| {
+                        const div = accumulator / base;
+                        digits[digits.len - 1 - i] = @intCast(accumulator - base * div);
+                        accumulator = div;
+                        base += 1;
+                    }
+
+                    const reg_numbers = [_]u3{ 1, 2, 3, 4, 5, 6 };
+                    var registers: [reg_numbers.len]u3 = undefined;
+                    var used_indices = [_]bool{false} ** reg_numbers.len;
+                    for (digits[digits.len - reg_count ..], 0..) |target_unused_index, i| {
+                        var unused_count: u8 = 0;
+                        const unused_index = for (used_indices, 0..) |used, index| {
+                            if (!used) {
+                                if (target_unused_index == unused_count) break index;
+                                unused_count += 1;
+                            }
+                        } else unreachable;
+
+                        registers[i] = reg_numbers[unused_index];
+                        used_indices[unused_index] = true;
+                    }
+
+                    var reg_addr = sp + stack_size - @sizeOf(usize) * @as(usize, reg_count + 1);
+                    if (ma.load(usize, reg_addr) == null) return error.InvalidUnwindInfo;
+                    for (0..reg_count) |i| {
+                        const reg_number = try Dwarf.compactUnwindToDwarfRegNumber(registers[i]);
+                        (try regValueNative(context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+                        reg_addr += @sizeOf(usize);
+                    }
+
+                    break :reg_blk reg_addr;
+                } else sp + stack_size - @sizeOf(usize);
+
+                const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+                const new_sp = ip_ptr + @sizeOf(usize);
+                if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
+
+                (try regValueNative(context.thread_context, spRegNum(reg_context), reg_context)).* = new_sp;
+                (try regValueNative(context.thread_context, ip_reg_num, reg_context)).* = new_ip;
+
+                break :blk new_ip;
+            },
+            .DWARF => {
+                return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
+            },
+        },
+        .aarch64 => switch (encoding.mode.arm64) {
+            .OLD => return error.UnimplementedUnwindEncoding,
+            .FRAMELESS => blk: {
+                const sp = (try regValueNative(context.thread_context, spRegNum(reg_context), reg_context)).*;
+                const new_sp = sp + encoding.value.arm64.frameless.stack_size * 16;
+                const new_ip = (try regValueNative(context.thread_context, 30, reg_context)).*;
+                if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
+                (try regValueNative(context.thread_context, spRegNum(reg_context), reg_context)).* = new_sp;
+                break :blk new_ip;
+            },
+            .DWARF => {
+                return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
+            },
+            .FRAME => blk: {
+                const fp = (try regValueNative(context.thread_context, fpRegNum(reg_context), reg_context)).*;
+                const new_sp = fp + 16;
+                const ip_ptr = fp + @sizeOf(usize);
+
+                const num_restored_pairs: usize =
+                    @popCount(@as(u5, @bitCast(encoding.value.arm64.frame.x_reg_pairs))) +
+                    @popCount(@as(u4, @bitCast(encoding.value.arm64.frame.d_reg_pairs)));
+                const min_reg_addr = fp - num_restored_pairs * 2 * @sizeOf(usize);
+
+                if (ma.load(usize, new_sp) == null or ma.load(usize, min_reg_addr) == null) return error.InvalidUnwindInfo;
+
+                var reg_addr = fp - @sizeOf(usize);
+                inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.x_reg_pairs)).Struct.fields, 0..) |field, i| {
+                    if (@field(encoding.value.arm64.frame.x_reg_pairs, field.name) != 0) {
+                        (try regValueNative(context.thread_context, 19 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+                        reg_addr += @sizeOf(usize);
+                        (try regValueNative(context.thread_context, 20 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+                        reg_addr += @sizeOf(usize);
+                    }
+                }
+
+                inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.d_reg_pairs)).Struct.fields, 0..) |field, i| {
+                    if (@field(encoding.value.arm64.frame.d_reg_pairs, field.name) != 0) {
+                        // Only the lower half of the 128-bit V registers are restored during unwinding
+                        @memcpy(
+                            try regBytes(context.thread_context, 64 + 8 + i, context.reg_context),
+                            std.mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
+                        );
+                        reg_addr += @sizeOf(usize);
+                        @memcpy(
+                            try regBytes(context.thread_context, 64 + 9 + i, context.reg_context),
+                            std.mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
+                        );
+                        reg_addr += @sizeOf(usize);
+                    }
+                }
+
+                const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+                const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
+
+                (try regValueNative(context.thread_context, fpRegNum(reg_context), reg_context)).* = new_fp;
+                (try regValueNative(context.thread_context, ip_reg_num, reg_context)).* = new_ip;
+
+                break :blk new_ip;
+            },
+        },
+        else => return error.UnimplementedArch,
+    };
+
+    context.pc = stripInstructionPtrAuthCode(new_ip);
+    if (context.pc > 0) context.pc -= 1;
+    return new_ip;
+}
+
+pub const UnwindContext = struct {
+    allocator: Allocator,
+    cfa: ?usize,
+    pc: usize,
+    thread_context: *std.debug.ThreadContext,
+    reg_context: Dwarf.abi.RegisterContext,
+    vm: VirtualMachine,
+    stack_machine: Dwarf.expression.StackMachine(.{ .call_frame_context = true }),
+
+    pub fn init(
+        allocator: Allocator,
+        thread_context: *std.debug.ThreadContext,
+    ) !UnwindContext {
+        comptime assert(supports_unwinding);
+
+        const pc = stripInstructionPtrAuthCode(
+            (try regValueNative(thread_context, ip_reg_num, null)).*,
+        );
+
+        const context_copy = try allocator.create(std.debug.ThreadContext);
+        std.debug.copyContext(thread_context, context_copy);
+
+        return .{
+            .allocator = allocator,
+            .cfa = null,
+            .pc = pc,
+            .thread_context = context_copy,
+            .reg_context = undefined,
+            .vm = .{},
+            .stack_machine = .{},
+        };
+    }
+
+    pub fn deinit(self: *UnwindContext) void {
+        self.vm.deinit(self.allocator);
+        self.stack_machine.deinit(self.allocator);
+        self.allocator.destroy(self.thread_context);
+        self.* = undefined;
+    }
+
+    pub fn getFp(self: *const UnwindContext) !usize {
+        return (try regValueNative(self.thread_context, fpRegNum(self.reg_context), self.reg_context)).*;
+    }
+};
+
+/// Some platforms use pointer authentication - the upper bits of instruction pointers contain a signature.
+/// This function clears these signature bits to make the pointer usable.
+pub inline fn stripInstructionPtrAuthCode(ptr: usize) usize {
+    if (native_arch == .aarch64) {
+        // `hint 0x07` maps to `xpaclri` (or `nop` if the hardware doesn't support it)
+        // The save / restore is because `xpaclri` operates on x30 (LR)
+        return asm (
+            \\mov x16, x30
+            \\mov x30, x15
+            \\hint 0x07
+            \\mov x15, x30
+            \\mov x30, x16
+            : [ret] "={x15}" (-> usize),
+            : [ptr] "{x15}" (ptr),
+            : "x16"
+        );
+    }
+
+    return ptr;
+}
+
+/// Unwind a stack frame using DWARF unwinding info, updating the register context.
+///
+/// If `.eh_frame_hdr` is available, it will be used to binary search for the FDE.
+/// Otherwise, a linear scan of `.eh_frame` and `.debug_frame` is done to find the FDE.
+///
+/// `explicit_fde_offset` is for cases where the FDE offset is known, such as when __unwind_info
+/// defers unwinding to DWARF. This is an offset into the `.eh_frame` section.
+pub fn unwindFrameDwarf(
+    di: *const Dwarf,
+    context: *UnwindContext,
+    ma: *std.debug.MemoryAccessor,
+    explicit_fde_offset: ?usize,
+) !usize {
+    if (!supports_unwinding) return error.UnsupportedCpuArchitecture;
+    if (context.pc == 0) return 0;
+
+    // Find the FDE and CIE
+    var cie: Dwarf.CommonInformationEntry = undefined;
+    var fde: Dwarf.FrameDescriptionEntry = undefined;
+
+    if (explicit_fde_offset) |fde_offset| {
+        const dwarf_section: Dwarf.Section.Id = .eh_frame;
+        const frame_section = di.section(dwarf_section) orelse return error.MissingFDE;
+        if (fde_offset >= frame_section.len) return error.MissingFDE;
+
+        var fbr: std.debug.DeprecatedFixedBufferReader = .{
+            .buf = frame_section,
+            .pos = fde_offset,
+            .endian = di.endian,
+        };
+
+        const fde_entry_header = try Dwarf.EntryHeader.read(&fbr, null, dwarf_section);
+        if (fde_entry_header.type != .fde) return error.MissingFDE;
+
+        const cie_offset = fde_entry_header.type.fde;
+        try fbr.seekTo(cie_offset);
+
+        fbr.endian = native_endian;
+        const cie_entry_header = try Dwarf.EntryHeader.read(&fbr, null, dwarf_section);
+        if (cie_entry_header.type != .cie) return Dwarf.bad();
+
+        cie = try Dwarf.CommonInformationEntry.parse(
+            cie_entry_header.entry_bytes,
+            0,
+            true,
+            cie_entry_header.format,
+            dwarf_section,
+            cie_entry_header.length_offset,
+            @sizeOf(usize),
+            native_endian,
+        );
+
+        fde = try Dwarf.FrameDescriptionEntry.parse(
+            fde_entry_header.entry_bytes,
+            0,
+            true,
+            cie,
+            @sizeOf(usize),
+            native_endian,
+        );
+    } else if (di.eh_frame_hdr) |header| {
+        const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
+        try header.findEntry(
+            ma,
+            eh_frame_len,
+            @intFromPtr(di.section(.eh_frame_hdr).?.ptr),
+            context.pc,
+            &cie,
+            &fde,
+        );
+    } else {
+        const index = std.sort.binarySearch(Dwarf.FrameDescriptionEntry, context.pc, di.fde_list.items, {}, struct {
+            pub fn compareFn(_: void, pc: usize, mid_item: Dwarf.FrameDescriptionEntry) std.math.Order {
+                if (pc < mid_item.pc_begin) return .lt;
+
+                const range_end = mid_item.pc_begin + mid_item.pc_range;
+                if (pc < range_end) return .eq;
+
+                return .gt;
+            }
+        }.compareFn);
+
+        fde = if (index) |i| di.fde_list.items[i] else return error.MissingFDE;
+        cie = di.cie_map.get(fde.cie_length_offset) orelse return error.MissingCIE;
+    }
+
+    var expression_context: Dwarf.expression.Context = .{
+        .format = cie.format,
+        .memory_accessor = ma,
+        .compile_unit = di.findCompileUnit(fde.pc_begin) catch null,
+        .thread_context = context.thread_context,
+        .reg_context = context.reg_context,
+        .cfa = context.cfa,
+    };
+
+    context.vm.reset();
+    context.reg_context.eh_frame = cie.version != 4;
+    context.reg_context.is_macho = di.is_macho;
+
+    const row = try context.vm.runToNative(context.allocator, context.pc, cie, fde);
+    context.cfa = switch (row.cfa.rule) {
+        .val_offset => |offset| blk: {
+            const register = row.cfa.register orelse return error.InvalidCFARule;
+            const value = mem.readInt(usize, (try regBytes(context.thread_context, register, context.reg_context))[0..@sizeOf(usize)], native_endian);
+            break :blk try applyOffset(value, offset);
+        },
+        .expression => |expr| blk: {
+            context.stack_machine.reset();
+            const value = try context.stack_machine.run(
+                expr,
+                context.allocator,
+                expression_context,
+                context.cfa,
+            );
+
+            if (value) |v| {
+                if (v != .generic) return error.InvalidExpressionValue;
+                break :blk v.generic;
+            } else return error.NoExpressionValue;
+        },
+        else => return error.InvalidCFARule,
+    };
+
+    if (ma.load(usize, context.cfa.?) == null) return error.InvalidCFA;
+    expression_context.cfa = context.cfa;
+
+    // Buffering the modifications is done because copying the thread context is not portable,
+    // some implementations (ie. darwin) use internal pointers to the mcontext.
+    var arena = std.heap.ArenaAllocator.init(context.allocator);
+    defer arena.deinit();
+    const update_allocator = arena.allocator();
+
+    const RegisterUpdate = struct {
+        // Backed by thread_context
+        dest: []u8,
+        // Backed by arena
+        src: []const u8,
+        prev: ?*@This(),
+    };
+
+    var update_tail: ?*RegisterUpdate = null;
+    var has_return_address = true;
+    for (context.vm.rowColumns(row)) |column| {
+        if (column.register) |register| {
+            if (register == cie.return_address_register) {
+                has_return_address = column.rule != .undefined;
+            }
+
+            const dest = try regBytes(context.thread_context, register, context.reg_context);
+            const src = try update_allocator.alloc(u8, dest.len);
+
+            const prev = update_tail;
+            update_tail = try update_allocator.create(RegisterUpdate);
+            update_tail.?.* = .{
+                .dest = dest,
+                .src = src,
+                .prev = prev,
+            };
+
+            try column.resolveValue(
+                context,
+                expression_context,
+                ma,
+                src,
+            );
+        }
+    }
+
+    // On all implemented architectures, the CFA is defined as being the previous frame's SP
+    (try regValueNative(context.thread_context, spRegNum(context.reg_context), context.reg_context)).* = context.cfa.?;
+
+    while (update_tail) |tail| {
+        @memcpy(tail.dest, tail.src);
+        update_tail = tail.prev;
+    }
+
+    if (has_return_address) {
+        context.pc = stripInstructionPtrAuthCode(mem.readInt(usize, (try regBytes(
+            context.thread_context,
+            cie.return_address_register,
+            context.reg_context,
+        ))[0..@sizeOf(usize)], native_endian));
+    } else {
+        context.pc = 0;
+    }
+
+    (try regValueNative(context.thread_context, ip_reg_num, context.reg_context)).* = context.pc;
+
+    // The call instruction will have pushed the address of the instruction that follows the call as the return address.
+    // This next instruction may be past the end of the function if the caller was `noreturn` (ie. the last instruction in
+    // the function was the call). If we were to look up an FDE entry using the return address directly, it could end up
+    // either not finding an FDE at all, or using the next FDE in the program, producing incorrect results. To prevent this,
+    // we subtract one so that the next lookup is guaranteed to land inside the
+    //
+    // The exception to this rule is signal frames, where we return execution would be returned to the instruction
+    // that triggered the handler.
+    const return_address = context.pc;
+    if (context.pc > 0 and !cie.isSignalFrame()) context.pc -= 1;
+
+    return return_address;
+}
+
+fn fpRegNum(reg_context: Dwarf.abi.RegisterContext) u8 {
+    return Dwarf.abi.fpRegNum(native_arch, reg_context);
+}
+
+fn spRegNum(reg_context: Dwarf.abi.RegisterContext) u8 {
+    return Dwarf.abi.spRegNum(native_arch, reg_context);
+}
+
+const ip_reg_num = Dwarf.abi.ipRegNum(native_arch).?;
+
+/// Tells whether unwinding for the host is implemented.
+pub const supports_unwinding = supportsUnwinding(builtin.target);
+
+comptime {
+    if (supports_unwinding) assert(Dwarf.abi.supportsUnwinding(builtin.target));
+}
+
+/// Tells whether unwinding for this target is *implemented* here in the Zig
+/// standard library.
+///
+/// See also `Dwarf.abi.supportsUnwinding` which tells whether Dwarf supports
+/// unwinding on that target *in theory*.
+pub fn supportsUnwinding(target: std.Target) bool {
+    return switch (target.cpu.arch) {
+        .x86 => switch (target.os.tag) {
+            .linux, .netbsd, .solaris, .illumos => true,
+            else => false,
+        },
+        .x86_64 => switch (target.os.tag) {
+            .linux, .netbsd, .freebsd, .openbsd, .macos, .ios, .solaris, .illumos => true,
+            else => false,
+        },
+        .arm => switch (target.os.tag) {
+            .linux => true,
+            else => false,
+        },
+        .aarch64 => switch (target.os.tag) {
+            .linux, .netbsd, .freebsd, .macos, .ios => true,
+            else => false,
+        },
+        // Unwinding is possible on other targets but this implementation does
+        // not support them...yet!
+        else => false,
+    };
+}
+
+fn unwindFrameMachODwarf(
+    context: *UnwindContext,
+    ma: *std.debug.MemoryAccessor,
+    eh_frame: []const u8,
+    fde_offset: usize,
+) !usize {
+    var di: Dwarf = .{
+        .endian = native_endian,
+        .is_macho = true,
+    };
+    defer di.deinit(context.allocator);
+
+    di.sections[@intFromEnum(Dwarf.Section.Id.eh_frame)] = .{
+        .data = eh_frame,
+        .owned = false,
+    };
+
+    return unwindFrameDwarf(&di, context, ma, fde_offset);
+}
+
+/// This is a virtual machine that runs DWARF call frame instructions.
+pub const VirtualMachine = struct {
+    /// See section 6.4.1 of the DWARF5 specification for details on each
+    const RegisterRule = union(enum) {
+        // The spec says that the default rule for each column is the undefined rule.
+        // However, it also allows ABI / compiler authors to specify alternate defaults, so
+        // there is a distinction made here.
+        default: void,
+        undefined: void,
+        same_value: void,
+        // offset(N)
+        offset: i64,
+        // val_offset(N)
+        val_offset: i64,
+        // register(R)
+        register: u8,
+        // expression(E)
+        expression: []const u8,
+        // val_expression(E)
+        val_expression: []const u8,
+        // Augmenter-defined rule
+        architectural: void,
+    };
+
+    /// Each row contains unwinding rules for a set of registers.
+    pub const Row = struct {
+        /// Offset from `FrameDescriptionEntry.pc_begin`
+        offset: u64 = 0,
+        /// Special-case column that defines the CFA (Canonical Frame Address) rule.
+        /// The register field of this column defines the register that CFA is derived from.
+        cfa: Column = .{},
+        /// The register fields in these columns define the register the rule applies to.
+        columns: ColumnRange = .{},
+        /// Indicates that the next write to any column in this row needs to copy
+        /// the backing column storage first, as it may be referenced by previous rows.
+        copy_on_write: bool = false,
+    };
+
+    pub const Column = struct {
+        register: ?u8 = null,
+        rule: RegisterRule = .{ .default = {} },
+
+        /// Resolves the register rule and places the result into `out` (see regBytes)
+        pub fn resolveValue(
+            self: Column,
+            context: *SelfInfo.UnwindContext,
+            expression_context: std.debug.Dwarf.expression.Context,
+            ma: *std.debug.MemoryAccessor,
+            out: []u8,
+        ) !void {
+            switch (self.rule) {
+                .default => {
+                    const register = self.register orelse return error.InvalidRegister;
+                    try getRegDefaultValue(register, context, out);
+                },
+                .undefined => {
+                    @memset(out, undefined);
+                },
+                .same_value => {
+                    // TODO: This copy could be eliminated if callers always copy the state then call this function to update it
+                    const register = self.register orelse return error.InvalidRegister;
+                    const src = try regBytes(context.thread_context, register, context.reg_context);
+                    if (src.len != out.len) return error.RegisterSizeMismatch;
+                    @memcpy(out, src);
+                },
+                .offset => |offset| {
+                    if (context.cfa) |cfa| {
+                        const addr = try applyOffset(cfa, offset);
+                        if (ma.load(usize, addr) == null) return error.InvalidAddress;
+                        const ptr: *const usize = @ptrFromInt(addr);
+                        mem.writeInt(usize, out[0..@sizeOf(usize)], ptr.*, native_endian);
+                    } else return error.InvalidCFA;
+                },
+                .val_offset => |offset| {
+                    if (context.cfa) |cfa| {
+                        mem.writeInt(usize, out[0..@sizeOf(usize)], try applyOffset(cfa, offset), native_endian);
+                    } else return error.InvalidCFA;
+                },
+                .register => |register| {
+                    const src = try regBytes(context.thread_context, register, context.reg_context);
+                    if (src.len != out.len) return error.RegisterSizeMismatch;
+                    @memcpy(out, try regBytes(context.thread_context, register, context.reg_context));
+                },
+                .expression => |expression| {
+                    context.stack_machine.reset();
+                    const value = try context.stack_machine.run(expression, context.allocator, expression_context, context.cfa.?);
+                    const addr = if (value) |v| blk: {
+                        if (v != .generic) return error.InvalidExpressionValue;
+                        break :blk v.generic;
+                    } else return error.NoExpressionValue;
+
+                    if (ma.load(usize, addr) == null) return error.InvalidExpressionAddress;
+                    const ptr: *usize = @ptrFromInt(addr);
+                    mem.writeInt(usize, out[0..@sizeOf(usize)], ptr.*, native_endian);
+                },
+                .val_expression => |expression| {
+                    context.stack_machine.reset();
+                    const value = try context.stack_machine.run(expression, context.allocator, expression_context, context.cfa.?);
+                    if (value) |v| {
+                        if (v != .generic) return error.InvalidExpressionValue;
+                        mem.writeInt(usize, out[0..@sizeOf(usize)], v.generic, native_endian);
+                    } else return error.NoExpressionValue;
+                },
+                .architectural => return error.UnimplementedRegisterRule,
+            }
+        }
+    };
+
+    const ColumnRange = struct {
+        /// Index into `columns` of the first column in this row.
+        start: usize = undefined,
+        len: u8 = 0,
+    };
+
+    columns: std.ArrayListUnmanaged(Column) = .{},
+    stack: std.ArrayListUnmanaged(ColumnRange) = .{},
+    current_row: Row = .{},
+
+    /// The result of executing the CIE's initial_instructions
+    cie_row: ?Row = null,
+
+    pub fn deinit(self: *VirtualMachine, allocator: std.mem.Allocator) void {
+        self.stack.deinit(allocator);
+        self.columns.deinit(allocator);
+        self.* = undefined;
+    }
+
+    pub fn reset(self: *VirtualMachine) void {
+        self.stack.clearRetainingCapacity();
+        self.columns.clearRetainingCapacity();
+        self.current_row = .{};
+        self.cie_row = null;
+    }
+
+    /// Return a slice backed by the row's non-CFA columns
+    pub fn rowColumns(self: VirtualMachine, row: Row) []Column {
+        if (row.columns.len == 0) return &.{};
+        return self.columns.items[row.columns.start..][0..row.columns.len];
+    }
+
+    /// Either retrieves or adds a column for `register` (non-CFA) in the current row.
+    fn getOrAddColumn(self: *VirtualMachine, allocator: std.mem.Allocator, register: u8) !*Column {
+        for (self.rowColumns(self.current_row)) |*c| {
+            if (c.register == register) return c;
+        }
+
+        if (self.current_row.columns.len == 0) {
+            self.current_row.columns.start = self.columns.items.len;
+        }
+        self.current_row.columns.len += 1;
+
+        const column = try self.columns.addOne(allocator);
+        column.* = .{
+            .register = register,
+        };
+
+        return column;
+    }
+
+    /// Runs the CIE instructions, then the FDE instructions. Execution halts
+    /// once the row that corresponds to `pc` is known, and the row is returned.
+    pub fn runTo(
+        self: *VirtualMachine,
+        allocator: std.mem.Allocator,
+        pc: u64,
+        cie: std.debug.Dwarf.CommonInformationEntry,
+        fde: std.debug.Dwarf.FrameDescriptionEntry,
+        addr_size_bytes: u8,
+        endian: std.builtin.Endian,
+    ) !Row {
+        assert(self.cie_row == null);
+        if (pc < fde.pc_begin or pc >= fde.pc_begin + fde.pc_range) return error.AddressOutOfRange;
+
+        var prev_row: Row = self.current_row;
+
+        var cie_stream = std.io.fixedBufferStream(cie.initial_instructions);
+        var fde_stream = std.io.fixedBufferStream(fde.instructions);
+        var streams = [_]*std.io.FixedBufferStream([]const u8){
+            &cie_stream,
+            &fde_stream,
+        };
+
+        for (&streams, 0..) |stream, i| {
+            while (stream.pos < stream.buffer.len) {
+                const instruction = try std.debug.Dwarf.call_frame.Instruction.read(stream, addr_size_bytes, endian);
+                prev_row = try self.step(allocator, cie, i == 0, instruction);
+                if (pc < fde.pc_begin + self.current_row.offset) return prev_row;
+            }
+        }
+
+        return self.current_row;
+    }
+
+    pub fn runToNative(
+        self: *VirtualMachine,
+        allocator: std.mem.Allocator,
+        pc: u64,
+        cie: std.debug.Dwarf.CommonInformationEntry,
+        fde: std.debug.Dwarf.FrameDescriptionEntry,
+    ) !Row {
+        return self.runTo(allocator, pc, cie, fde, @sizeOf(usize), native_endian);
+    }
+
+    fn resolveCopyOnWrite(self: *VirtualMachine, allocator: std.mem.Allocator) !void {
+        if (!self.current_row.copy_on_write) return;
+
+        const new_start = self.columns.items.len;
+        if (self.current_row.columns.len > 0) {
+            try self.columns.ensureUnusedCapacity(allocator, self.current_row.columns.len);
+            self.columns.appendSliceAssumeCapacity(self.rowColumns(self.current_row));
+            self.current_row.columns.start = new_start;
+        }
+    }
+
+    /// Executes a single instruction.
+    /// If this instruction is from the CIE, `is_initial` should be set.
+    /// Returns the value of `current_row` before executing this instruction.
+    pub fn step(
+        self: *VirtualMachine,
+        allocator: std.mem.Allocator,
+        cie: std.debug.Dwarf.CommonInformationEntry,
+        is_initial: bool,
+        instruction: Dwarf.call_frame.Instruction,
+    ) !Row {
+        // CIE instructions must be run before FDE instructions
+        assert(!is_initial or self.cie_row == null);
+        if (!is_initial and self.cie_row == null) {
+            self.cie_row = self.current_row;
+            self.current_row.copy_on_write = true;
+        }
+
+        const prev_row = self.current_row;
+        switch (instruction) {
+            .set_loc => |i| {
+                if (i.address <= self.current_row.offset) return error.InvalidOperation;
+                // TODO: Check cie.segment_selector_size != 0 for DWARFV4
+                self.current_row.offset = i.address;
+            },
+            inline .advance_loc,
+            .advance_loc1,
+            .advance_loc2,
+            .advance_loc4,
+            => |i| {
+                self.current_row.offset += i.delta * cie.code_alignment_factor;
+                self.current_row.copy_on_write = true;
+            },
+            inline .offset,
+            .offset_extended,
+            .offset_extended_sf,
+            => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{ .offset = @as(i64, @intCast(i.offset)) * cie.data_alignment_factor };
+            },
+            inline .restore,
+            .restore_extended,
+            => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                if (self.cie_row) |cie_row| {
+                    const column = try self.getOrAddColumn(allocator, i.register);
+                    column.rule = for (self.rowColumns(cie_row)) |cie_column| {
+                        if (cie_column.register == i.register) break cie_column.rule;
+                    } else .{ .default = {} };
+                } else return error.InvalidOperation;
+            },
+            .nop => {},
+            .undefined => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{ .undefined = {} };
+            },
+            .same_value => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{ .same_value = {} };
+            },
+            .register => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{ .register = i.target_register };
+            },
+            .remember_state => {
+                try self.stack.append(allocator, self.current_row.columns);
+                self.current_row.copy_on_write = true;
+            },
+            .restore_state => {
+                const restored_columns = self.stack.popOrNull() orelse return error.InvalidOperation;
+                self.columns.shrinkRetainingCapacity(self.columns.items.len - self.current_row.columns.len);
+                try self.columns.ensureUnusedCapacity(allocator, restored_columns.len);
+
+                self.current_row.columns.start = self.columns.items.len;
+                self.current_row.columns.len = restored_columns.len;
+                self.columns.appendSliceAssumeCapacity(self.columns.items[restored_columns.start..][0..restored_columns.len]);
+            },
+            .def_cfa => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                self.current_row.cfa = .{
+                    .register = i.register,
+                    .rule = .{ .val_offset = @intCast(i.offset) },
+                };
+            },
+            .def_cfa_sf => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                self.current_row.cfa = .{
+                    .register = i.register,
+                    .rule = .{ .val_offset = i.offset * cie.data_alignment_factor },
+                };
+            },
+            .def_cfa_register => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
+                self.current_row.cfa.register = i.register;
+            },
+            .def_cfa_offset => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
+                self.current_row.cfa.rule = .{
+                    .val_offset = @intCast(i.offset),
+                };
+            },
+            .def_cfa_offset_sf => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
+                self.current_row.cfa.rule = .{
+                    .val_offset = i.offset * cie.data_alignment_factor,
+                };
+            },
+            .def_cfa_expression => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                self.current_row.cfa.register = undefined;
+                self.current_row.cfa.rule = .{
+                    .expression = i.block,
+                };
+            },
+            .expression => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{
+                    .expression = i.block,
+                };
+            },
+            .val_offset => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{
+                    .val_offset = @as(i64, @intCast(i.offset)) * cie.data_alignment_factor,
+                };
+            },
+            .val_offset_sf => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{
+                    .val_offset = i.offset * cie.data_alignment_factor,
+                };
+            },
+            .val_expression => |i| {
+                try self.resolveCopyOnWrite(allocator);
+                const column = try self.getOrAddColumn(allocator, i.register);
+                column.rule = .{
+                    .val_expression = i.block,
+                };
+            },
+        }
+
+        return prev_row;
+    }
+};
+
+/// Returns the ABI-defined default value this register has in the unwinding table
+/// before running any of the CIE instructions. The DWARF spec defines these as having
+/// the .undefined rule by default, but allows ABI authors to override that.
+fn getRegDefaultValue(reg_number: u8, context: *UnwindContext, out: []u8) !void {
+    switch (builtin.cpu.arch) {
+        .aarch64 => {
+            // Callee-saved registers are initialized as if they had the .same_value rule
+            if (reg_number >= 19 and reg_number <= 28) {
+                const src = try regBytes(context.thread_context, reg_number, context.reg_context);
+                if (src.len != out.len) return error.RegisterSizeMismatch;
+                @memcpy(out, src);
+                return;
+            }
+        },
+        else => {},
+    }
+
+    @memset(out, undefined);
+}
+
+/// Since register rules are applied (usually) during a panic,
+/// checked addition / subtraction is used so that we can return
+/// an error and fall back to FP-based unwinding.
+fn applyOffset(base: usize, offset: i64) !usize {
+    return if (offset >= 0)
+        try std.math.add(usize, base, @as(usize, @intCast(offset)))
+    else
+        try std.math.sub(usize, base, @as(usize, @intCast(-offset)));
+}
diff --git a/lib/std/pdb.zig b/lib/std/pdb.zig
index ece1cc63dc..31ad02e945 100644
--- a/lib/std/pdb.zig
+++ b/lib/std/pdb.zig
@@ -1,3 +1,12 @@
+//! Program Data Base debugging information format.
+//!
+//! This namespace contains unopinionated types and data definitions only. For
+//! an implementation of parsing and caching PDB information, see
+//! `std.debug.Pdb`.
+//!
+//! Most of this is based on information gathered from LLVM source code,
+//! documentation and/or contributors.
+
 const std = @import("std.zig");
 const io = std.io;
 const math = std.math;
@@ -9,10 +18,7 @@ const debug = std.debug;
 
 const ArrayList = std.ArrayList;
 
-// Note: most of this is based on information gathered from LLVM source code,
-// documentation and/or contributors.
-
-// https://llvm.org/docs/PDB/DbiStream.html#stream-header
+/// https://llvm.org/docs/PDB/DbiStream.html#stream-header
 pub const DbiStreamHeader = extern struct {
     VersionSignature: i32,
     VersionHeader: u32,
@@ -415,10 +421,8 @@ pub const ColumnNumberEntry = extern struct {
 pub const FileChecksumEntryHeader = extern struct {
     /// Byte offset of filename in global string table.
     FileNameOffset: u32,
-
     /// Number of bytes of checksum.
     ChecksumSize: u8,
-
     /// FileChecksumKind
     ChecksumKind: u8,
 };
@@ -451,525 +455,15 @@ pub const DebugSubsectionHeader = extern struct {
     Length: u32,
 };
 
-pub const PDBStringTableHeader = extern struct {
+pub const StringTableHeader = extern struct {
     /// PDBStringTableSignature
     Signature: u32,
-
     /// 1 or 2
     HashVersion: u32,
-
     /// Number of bytes of names buffer.
     ByteSize: u32,
 };
 
-fn readSparseBitVector(stream: anytype, allocator: mem.Allocator) ![]u32 {
-    const num_words = try stream.readInt(u32, .little);
-    var list = ArrayList(u32).init(allocator);
-    errdefer list.deinit();
-    var word_i: u32 = 0;
-    while (word_i != num_words) : (word_i += 1) {
-        const word = try stream.readInt(u32, .little);
-        var bit_i: u5 = 0;
-        while (true) : (bit_i += 1) {
-            if (word & (@as(u32, 1) << bit_i) != 0) {
-                try list.append(word_i * 32 + bit_i);
-            }
-            if (bit_i == std.math.maxInt(u5)) break;
-        }
-    }
-    return try list.toOwnedSlice();
-}
-
-pub const Pdb = struct {
-    in_file: File,
-    msf: Msf,
-    allocator: mem.Allocator,
-    string_table: ?*MsfStream,
-    dbi: ?*MsfStream,
-    modules: []Module,
-    sect_contribs: []SectionContribEntry,
-    guid: [16]u8,
-    age: u32,
-
-    pub const Module = struct {
-        mod_info: ModInfo,
-        module_name: []u8,
-        obj_file_name: []u8,
-        // The fields below are filled on demand.
-        populated: bool,
-        symbols: []u8,
-        subsect_info: []u8,
-        checksum_offset: ?usize,
-
-        pub fn deinit(self: *Module, allocator: mem.Allocator) void {
-            allocator.free(self.module_name);
-            allocator.free(self.obj_file_name);
-            if (self.populated) {
-                allocator.free(self.symbols);
-                allocator.free(self.subsect_info);
-            }
-        }
-    };
-
-    pub fn init(allocator: mem.Allocator, path: []const u8) !Pdb {
-        const file = try fs.cwd().openFile(path, .{});
-        errdefer file.close();
-
-        return Pdb{
-            .in_file = file,
-            .allocator = allocator,
-            .string_table = null,
-            .dbi = null,
-            .msf = try Msf.init(allocator, file),
-            .modules = &[_]Module{},
-            .sect_contribs = &[_]SectionContribEntry{},
-            .guid = undefined,
-            .age = undefined,
-        };
-    }
-
-    pub fn deinit(self: *Pdb) void {
-        self.in_file.close();
-        self.msf.deinit(self.allocator);
-        for (self.modules) |*module| {
-            module.deinit(self.allocator);
-        }
-        self.allocator.free(self.modules);
-        self.allocator.free(self.sect_contribs);
-    }
-
-    pub fn parseDbiStream(self: *Pdb) !void {
-        var stream = self.getStream(StreamType.Dbi) orelse
-            return error.InvalidDebugInfo;
-        const reader = stream.reader();
-
-        const header = try reader.readStruct(DbiStreamHeader);
-        if (header.VersionHeader != 19990903) // V70, only value observed by LLVM team
-            return error.UnknownPDBVersion;
-        // if (header.Age != age)
-        //     return error.UnmatchingPDB;
-
-        const mod_info_size = header.ModInfoSize;
-        const section_contrib_size = header.SectionContributionSize;
-
-        var modules = ArrayList(Module).init(self.allocator);
-        errdefer modules.deinit();
-
-        // Module Info Substream
-        var mod_info_offset: usize = 0;
-        while (mod_info_offset != mod_info_size) {
-            const mod_info = try reader.readStruct(ModInfo);
-            var this_record_len: usize = @sizeOf(ModInfo);
-
-            const module_name = try reader.readUntilDelimiterAlloc(self.allocator, 0, 1024);
-            errdefer self.allocator.free(module_name);
-            this_record_len += module_name.len + 1;
-
-            const obj_file_name = try reader.readUntilDelimiterAlloc(self.allocator, 0, 1024);
-            errdefer self.allocator.free(obj_file_name);
-            this_record_len += obj_file_name.len + 1;
-
-            if (this_record_len % 4 != 0) {
-                const round_to_next_4 = (this_record_len | 0x3) + 1;
-                const march_forward_bytes = round_to_next_4 - this_record_len;
-                try stream.seekBy(@as(isize, @intCast(march_forward_bytes)));
-                this_record_len += march_forward_bytes;
-            }
-
-            try modules.append(Module{
-                .mod_info = mod_info,
-                .module_name = module_name,
-                .obj_file_name = obj_file_name,
-
-                .populated = false,
-                .symbols = undefined,
-                .subsect_info = undefined,
-                .checksum_offset = null,
-            });
-
-            mod_info_offset += this_record_len;
-            if (mod_info_offset > mod_info_size)
-                return error.InvalidDebugInfo;
-        }
-
-        // Section Contribution Substream
-        var sect_contribs = ArrayList(SectionContribEntry).init(self.allocator);
-        errdefer sect_contribs.deinit();
-
-        var sect_cont_offset: usize = 0;
-        if (section_contrib_size != 0) {
-            const version = reader.readEnum(SectionContrSubstreamVersion, .little) catch |err| switch (err) {
-                error.InvalidValue => return error.InvalidDebugInfo,
-                else => |e| return e,
-            };
-            _ = version;
-            sect_cont_offset += @sizeOf(u32);
-        }
-        while (sect_cont_offset != section_contrib_size) {
-            const entry = try sect_contribs.addOne();
-            entry.* = try reader.readStruct(SectionContribEntry);
-            sect_cont_offset += @sizeOf(SectionContribEntry);
-
-            if (sect_cont_offset > section_contrib_size)
-                return error.InvalidDebugInfo;
-        }
-
-        self.modules = try modules.toOwnedSlice();
-        self.sect_contribs = try sect_contribs.toOwnedSlice();
-    }
-
-    pub fn parseInfoStream(self: *Pdb) !void {
-        var stream = self.getStream(StreamType.Pdb) orelse
-            return error.InvalidDebugInfo;
-        const reader = stream.reader();
-
-        // Parse the InfoStreamHeader.
-        const version = try reader.readInt(u32, .little);
-        const signature = try reader.readInt(u32, .little);
-        _ = signature;
-        const age = try reader.readInt(u32, .little);
-        const guid = try reader.readBytesNoEof(16);
-
-        if (version != 20000404) // VC70, only value observed by LLVM team
-            return error.UnknownPDBVersion;
-
-        self.guid = guid;
-        self.age = age;
-
-        // Find the string table.
-        const string_table_index = str_tab_index: {
-            const name_bytes_len = try reader.readInt(u32, .little);
-            const name_bytes = try self.allocator.alloc(u8, name_bytes_len);
-            defer self.allocator.free(name_bytes);
-            try reader.readNoEof(name_bytes);
-
-            const HashTableHeader = extern struct {
-                Size: u32,
-                Capacity: u32,
-
-                fn maxLoad(cap: u32) u32 {
-                    return cap * 2 / 3 + 1;
-                }
-            };
-            const hash_tbl_hdr = try reader.readStruct(HashTableHeader);
-            if (hash_tbl_hdr.Capacity == 0)
-                return error.InvalidDebugInfo;
-
-            if (hash_tbl_hdr.Size > HashTableHeader.maxLoad(hash_tbl_hdr.Capacity))
-                return error.InvalidDebugInfo;
-
-            const present = try readSparseBitVector(&reader, self.allocator);
-            defer self.allocator.free(present);
-            if (present.len != hash_tbl_hdr.Size)
-                return error.InvalidDebugInfo;
-            const deleted = try readSparseBitVector(&reader, self.allocator);
-            defer self.allocator.free(deleted);
-
-            for (present) |_| {
-                const name_offset = try reader.readInt(u32, .little);
-                const name_index = try reader.readInt(u32, .little);
-                if (name_offset > name_bytes.len)
-                    return error.InvalidDebugInfo;
-                const name = mem.sliceTo(name_bytes[name_offset..], 0);
-                if (mem.eql(u8, name, "/names")) {
-                    break :str_tab_index name_index;
-                }
-            }
-            return error.MissingDebugInfo;
-        };
-
-        self.string_table = self.getStreamById(string_table_index) orelse
-            return error.MissingDebugInfo;
-    }
-
-    pub fn getSymbolName(self: *Pdb, module: *Module, address: u64) ?[]const u8 {
-        _ = self;
-        std.debug.assert(module.populated);
-
-        var symbol_i: usize = 0;
-        while (symbol_i != module.symbols.len) {
-            const prefix = @as(*align(1) RecordPrefix, @ptrCast(&module.symbols[symbol_i]));
-            if (prefix.RecordLen < 2)
-                return null;
-            switch (prefix.RecordKind) {
-                .S_LPROC32, .S_GPROC32 => {
-                    const proc_sym = @as(*align(1) ProcSym, @ptrCast(&module.symbols[symbol_i + @sizeOf(RecordPrefix)]));
-                    if (address >= proc_sym.CodeOffset and address < proc_sym.CodeOffset + proc_sym.CodeSize) {
-                        return mem.sliceTo(@as([*:0]u8, @ptrCast(&proc_sym.Name[0])), 0);
-                    }
-                },
-                else => {},
-            }
-            symbol_i += prefix.RecordLen + @sizeOf(u16);
-        }
-
-        return null;
-    }
-
-    pub fn getLineNumberInfo(self: *Pdb, module: *Module, address: u64) !debug.LineInfo {
-        std.debug.assert(module.populated);
-        const subsect_info = module.subsect_info;
-
-        var sect_offset: usize = 0;
-        var skip_len: usize = undefined;
-        const checksum_offset = module.checksum_offset orelse return error.MissingDebugInfo;
-        while (sect_offset != subsect_info.len) : (sect_offset += skip_len) {
-            const subsect_hdr = @as(*align(1) DebugSubsectionHeader, @ptrCast(&subsect_info[sect_offset]));
-            skip_len = subsect_hdr.Length;
-            sect_offset += @sizeOf(DebugSubsectionHeader);
-
-            switch (subsect_hdr.Kind) {
-                .Lines => {
-                    var line_index = sect_offset;
-
-                    const line_hdr = @as(*align(1) LineFragmentHeader, @ptrCast(&subsect_info[line_index]));
-                    if (line_hdr.RelocSegment == 0)
-                        return error.MissingDebugInfo;
-                    line_index += @sizeOf(LineFragmentHeader);
-                    const frag_vaddr_start = line_hdr.RelocOffset;
-                    const frag_vaddr_end = frag_vaddr_start + line_hdr.CodeSize;
-
-                    if (address >= frag_vaddr_start and address < frag_vaddr_end) {
-                        // There is an unknown number of LineBlockFragmentHeaders (and their accompanying line and column records)
-                        // from now on. We will iterate through them, and eventually find a LineInfo that we're interested in,
-                        // breaking out to :subsections. If not, we will make sure to not read anything outside of this subsection.
-                        const subsection_end_index = sect_offset + subsect_hdr.Length;
-
-                        while (line_index < subsection_end_index) {
-                            const block_hdr = @as(*align(1) LineBlockFragmentHeader, @ptrCast(&subsect_info[line_index]));
-                            line_index += @sizeOf(LineBlockFragmentHeader);
-                            const start_line_index = line_index;
-
-                            const has_column = line_hdr.Flags.LF_HaveColumns;
-
-                            // All line entries are stored inside their line block by ascending start address.
-                            // Heuristic: we want to find the last line entry
-                            // that has a vaddr_start <= address.
-                            // This is done with a simple linear search.
-                            var line_i: u32 = 0;
-                            while (line_i < block_hdr.NumLines) : (line_i += 1) {
-                                const line_num_entry = @as(*align(1) LineNumberEntry, @ptrCast(&subsect_info[line_index]));
-                                line_index += @sizeOf(LineNumberEntry);
-
-                                const vaddr_start = frag_vaddr_start + line_num_entry.Offset;
-                                if (address < vaddr_start) {
-                                    break;
-                                }
-                            }
-
-                            // line_i == 0 would mean that no matching LineNumberEntry was found.
-                            if (line_i > 0) {
-                                const subsect_index = checksum_offset + block_hdr.NameIndex;
-                                const chksum_hdr = @as(*align(1) FileChecksumEntryHeader, @ptrCast(&module.subsect_info[subsect_index]));
-                                const strtab_offset = @sizeOf(PDBStringTableHeader) + chksum_hdr.FileNameOffset;
-                                try self.string_table.?.seekTo(strtab_offset);
-                                const source_file_name = try self.string_table.?.reader().readUntilDelimiterAlloc(self.allocator, 0, 1024);
-
-                                const line_entry_idx = line_i - 1;
-
-                                const column = if (has_column) blk: {
-                                    const start_col_index = start_line_index + @sizeOf(LineNumberEntry) * block_hdr.NumLines;
-                                    const col_index = start_col_index + @sizeOf(ColumnNumberEntry) * line_entry_idx;
-                                    const col_num_entry = @as(*align(1) ColumnNumberEntry, @ptrCast(&subsect_info[col_index]));
-                                    break :blk col_num_entry.StartColumn;
-                                } else 0;
-
-                                const found_line_index = start_line_index + line_entry_idx * @sizeOf(LineNumberEntry);
-                                const line_num_entry: *align(1) LineNumberEntry = @ptrCast(&subsect_info[found_line_index]);
-                                const flags: *align(1) LineNumberEntry.Flags = @ptrCast(&line_num_entry.Flags);
-
-                                return debug.LineInfo{
-                                    .file_name = source_file_name,
-                                    .line = flags.Start,
-                                    .column = column,
-                                };
-                            }
-                        }
-
-                        // Checking that we are not reading garbage after the (possibly) multiple block fragments.
-                        if (line_index != subsection_end_index) {
-                            return error.InvalidDebugInfo;
-                        }
-                    }
-                },
-                else => {},
-            }
-
-            if (sect_offset > subsect_info.len)
-                return error.InvalidDebugInfo;
-        }
-
-        return error.MissingDebugInfo;
-    }
-
-    pub fn getModule(self: *Pdb, index: usize) !?*Module {
-        if (index >= self.modules.len)
-            return null;
-
-        const mod = &self.modules[index];
-        if (mod.populated)
-            return mod;
-
-        // At most one can be non-zero.
-        if (mod.mod_info.C11ByteSize != 0 and mod.mod_info.C13ByteSize != 0)
-            return error.InvalidDebugInfo;
-        if (mod.mod_info.C13ByteSize == 0)
-            return error.InvalidDebugInfo;
-
-        const stream = self.getStreamById(mod.mod_info.ModuleSymStream) orelse
-            return error.MissingDebugInfo;
-        const reader = stream.reader();
-
-        const signature = try reader.readInt(u32, .little);
-        if (signature != 4)
-            return error.InvalidDebugInfo;
-
-        mod.symbols = try self.allocator.alloc(u8, mod.mod_info.SymByteSize - 4);
-        errdefer self.allocator.free(mod.symbols);
-        try reader.readNoEof(mod.symbols);
-
-        mod.subsect_info = try self.allocator.alloc(u8, mod.mod_info.C13ByteSize);
-        errdefer self.allocator.free(mod.subsect_info);
-        try reader.readNoEof(mod.subsect_info);
-
-        var sect_offset: usize = 0;
-        var skip_len: usize = undefined;
-        while (sect_offset != mod.subsect_info.len) : (sect_offset += skip_len) {
-            const subsect_hdr = @as(*align(1) DebugSubsectionHeader, @ptrCast(&mod.subsect_info[sect_offset]));
-            skip_len = subsect_hdr.Length;
-            sect_offset += @sizeOf(DebugSubsectionHeader);
-
-            switch (subsect_hdr.Kind) {
-                .FileChecksums => {
-                    mod.checksum_offset = sect_offset;
-                    break;
-                },
-                else => {},
-            }
-
-            if (sect_offset > mod.subsect_info.len)
-                return error.InvalidDebugInfo;
-        }
-
-        mod.populated = true;
-        return mod;
-    }
-
-    pub fn getStreamById(self: *Pdb, id: u32) ?*MsfStream {
-        if (id >= self.msf.streams.len)
-            return null;
-        return &self.msf.streams[id];
-    }
-
-    pub fn getStream(self: *Pdb, stream: StreamType) ?*MsfStream {
-        const id = @intFromEnum(stream);
-        return self.getStreamById(id);
-    }
-};
-
-// see https://llvm.org/docs/PDB/MsfFile.html
-const Msf = struct {
-    directory: MsfStream,
-    streams: []MsfStream,
-
-    fn init(allocator: mem.Allocator, file: File) !Msf {
-        const in = file.reader();
-
-        const superblock = try in.readStruct(SuperBlock);
-
-        // Sanity checks
-        if (!mem.eql(u8, &superblock.FileMagic, SuperBlock.file_magic))
-            return error.InvalidDebugInfo;
-        if (superblock.FreeBlockMapBlock != 1 and superblock.FreeBlockMapBlock != 2)
-            return error.InvalidDebugInfo;
-        const file_len = try file.getEndPos();
-        if (superblock.NumBlocks * superblock.BlockSize != file_len)
-            return error.InvalidDebugInfo;
-        switch (superblock.BlockSize) {
-            // llvm only supports 4096 but we can handle any of these values
-            512, 1024, 2048, 4096 => {},
-            else => return error.InvalidDebugInfo,
-        }
-
-        const dir_block_count = blockCountFromSize(superblock.NumDirectoryBytes, superblock.BlockSize);
-        if (dir_block_count > superblock.BlockSize / @sizeOf(u32))
-            return error.UnhandledBigDirectoryStream; // cf. BlockMapAddr comment.
-
-        try file.seekTo(superblock.BlockSize * superblock.BlockMapAddr);
-        const dir_blocks = try allocator.alloc(u32, dir_block_count);
-        for (dir_blocks) |*b| {
-            b.* = try in.readInt(u32, .little);
-        }
-        var directory = MsfStream.init(
-            superblock.BlockSize,
-            file,
-            dir_blocks,
-        );
-
-        const begin = directory.pos;
-        const stream_count = try directory.reader().readInt(u32, .little);
-        const stream_sizes = try allocator.alloc(u32, stream_count);
-        defer allocator.free(stream_sizes);
-
-        // Microsoft's implementation uses @as(u32, -1) for inexistent streams.
-        // These streams are not used, but still participate in the file
-        // and must be taken into account when resolving stream indices.
-        const Nil = 0xFFFFFFFF;
-        for (stream_sizes) |*s| {
-            const size = try directory.reader().readInt(u32, .little);
-            s.* = if (size == Nil) 0 else blockCountFromSize(size, superblock.BlockSize);
-        }
-
-        const streams = try allocator.alloc(MsfStream, stream_count);
-        for (streams, 0..) |*stream, i| {
-            const size = stream_sizes[i];
-            if (size == 0) {
-                stream.* = MsfStream{
-                    .blocks = &[_]u32{},
-                };
-            } else {
-                var blocks = try allocator.alloc(u32, size);
-                var j: u32 = 0;
-                while (j < size) : (j += 1) {
-                    const block_id = try directory.reader().readInt(u32, .little);
-                    const n = (block_id % superblock.BlockSize);
-                    // 0 is for SuperBlock, 1 and 2 for FPMs.
-                    if (block_id == 0 or n == 1 or n == 2 or block_id * superblock.BlockSize > file_len)
-                        return error.InvalidBlockIndex;
-                    blocks[j] = block_id;
-                }
-
-                stream.* = MsfStream.init(
-                    superblock.BlockSize,
-                    file,
-                    blocks,
-                );
-            }
-        }
-
-        const end = directory.pos;
-        if (end - begin != superblock.NumDirectoryBytes)
-            return error.InvalidStreamDirectory;
-
-        return Msf{
-            .directory = directory,
-            .streams = streams,
-        };
-    }
-
-    fn deinit(self: *Msf, allocator: mem.Allocator) void {
-        allocator.free(self.directory.blocks);
-        for (self.streams) |*stream| {
-            allocator.free(stream.blocks);
-        }
-        allocator.free(self.streams);
-    }
-};
-
-fn blockCountFromSize(size: u32, block_size: u32) u32 {
-    return (size + block_size - 1) / block_size;
-}
-
 // https://llvm.org/docs/PDB/MsfFile.html#the-superblock
 pub const SuperBlock = extern struct {
     /// The LLVM docs list a space between C / C++ but empirically this is not the case.
@@ -1016,82 +510,3 @@ pub const SuperBlock = extern struct {
     // implement it so we're kind of safe making this assumption for now.
     BlockMapAddr: u32,
 };
-
-const MsfStream = struct {
-    in_file: File = undefined,
-    pos: u64 = undefined,
-    blocks: []u32 = undefined,
-    block_size: u32 = undefined,
-
-    pub const Error = @typeInfo(@typeInfo(@TypeOf(read)).Fn.return_type.?).ErrorUnion.error_set;
-
-    fn init(block_size: u32, file: File, blocks: []u32) MsfStream {
-        const stream = MsfStream{
-            .in_file = file,
-            .pos = 0,
-            .blocks = blocks,
-            .block_size = block_size,
-        };
-
-        return stream;
-    }
-
-    fn read(self: *MsfStream, buffer: []u8) !usize {
-        var block_id = @as(usize, @intCast(self.pos / self.block_size));
-        if (block_id >= self.blocks.len) return 0; // End of Stream
-        var block = self.blocks[block_id];
-        var offset = self.pos % self.block_size;
-
-        try self.in_file.seekTo(block * self.block_size + offset);
-        const in = self.in_file.reader();
-
-        var size: usize = 0;
-        var rem_buffer = buffer;
-        while (size < buffer.len) {
-            const size_to_read = @min(self.block_size - offset, rem_buffer.len);
-            size += try in.read(rem_buffer[0..size_to_read]);
-            rem_buffer = buffer[size..];
-            offset += size_to_read;
-
-            // If we're at the end of a block, go to the next one.
-            if (offset == self.block_size) {
-                offset = 0;
-                block_id += 1;
-                if (block_id >= self.blocks.len) break; // End of Stream
-                block = self.blocks[block_id];
-                try self.in_file.seekTo(block * self.block_size);
-            }
-        }
-
-        self.pos += buffer.len;
-        return buffer.len;
-    }
-
-    pub fn seekBy(self: *MsfStream, len: i64) !void {
-        self.pos = @as(u64, @intCast(@as(i64, @intCast(self.pos)) + len));
-        if (self.pos >= self.blocks.len * self.block_size)
-            return error.EOF;
-    }
-
-    pub fn seekTo(self: *MsfStream, len: u64) !void {
-        self.pos = len;
-        if (self.pos >= self.blocks.len * self.block_size)
-            return error.EOF;
-    }
-
-    fn getSize(self: *const MsfStream) u64 {
-        return self.blocks.len * self.block_size;
-    }
-
-    fn getFilePos(self: MsfStream) u64 {
-        const block_id = self.pos / self.block_size;
-        const block = self.blocks[block_id];
-        const offset = self.pos % self.block_size;
-
-        return block * self.block_size + offset;
-    }
-
-    pub fn reader(self: *MsfStream) std.io.Reader(*MsfStream, Error, read) {
-        return .{ .context = self };
-    }
-};