Merge remote-tracking branch 'origin/master' into llvm16

28 files changed, 460 insertions, 2590 deletions

diff --git a/src/AstGen.zig b/src/AstGen.zig
index 10673a2b37..40eef32d4e 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -1730,7 +1730,8 @@ fn structInitExprRlNone(
                 .container_type = ty_inst,
                 .name_start = str_index,
             }) } }
-        else .{ .rl = .none };
+        else
+            .{ .rl = .none };
         setExtra(astgen, extra_index, Zir.Inst.StructInitAnon.Item{
             .field_name = str_index,
             .init = try expr(gz, scope, sub_ri, field_init),
@@ -2530,7 +2531,6 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .bit_size_of,
             .typeof_log2_int_type,
             .ptr_to_int,
-            .qual_cast,
             .align_of,
             .bool_to_int,
             .embed_file,
@@ -8038,7 +8038,6 @@ fn builtinCall(
         .float_cast   => return typeCast(gz, scope, ri, node, params[0], params[1], .float_cast),
         .int_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .int_cast),
         .ptr_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .ptr_cast),
-        .qual_cast    => return typeCast(gz, scope, ri, node, params[0], params[1], .qual_cast),
         .truncate     => return typeCast(gz, scope, ri, node, params[0], params[1], .truncate),
         // zig fmt: on
 
@@ -8114,6 +8113,22 @@ fn builtinCall(
             });
             return rvalue(gz, ri, result, node);
         },
+        .const_cast => {
+            const operand = try expr(gz, scope, .{ .rl = .none }, params[0]);
+            const result = try gz.addExtendedPayload(.const_cast, Zir.Inst.UnNode{
+                .node = gz.nodeIndexToRelative(node),
+                .operand = operand,
+            });
+            return rvalue(gz, ri, result, node);
+        },
+        .volatile_cast => {
+            const operand = try expr(gz, scope, .{ .rl = .none }, params[0]);
+            const result = try gz.addExtendedPayload(.volatile_cast, Zir.Inst.UnNode{
+                .node = gz.nodeIndexToRelative(node),
+                .operand = operand,
+            });
+            return rvalue(gz, ri, result, node);
+        },
 
         // zig fmt: off
         .has_decl  => return hasDeclOrField(gz, scope, ri, node, params[0], params[1], .has_decl),
diff --git a/src/Autodoc.zig b/src/Autodoc.zig
index 0c2c39bbcc..44325e3836 100644
--- a/src/Autodoc.zig
+++ b/src/Autodoc.zig
@@ -1400,7 +1400,6 @@ fn walkInstruction(
         .float_cast,
         .int_cast,
         .ptr_cast,
-        .qual_cast,
         .truncate,
         .align_cast,
         .has_decl,
@@ -2983,6 +2982,8 @@ fn walkInstruction(
                 .error_to_int,
                 .int_to_error,
                 .reify,
+                .const_cast,
+                .volatile_cast,
                 => {
                     const extra = file.zir.extraData(Zir.Inst.UnNode, extended.operand).data;
                     const bin_index = self.exprs.items.len;
diff --git a/src/BuiltinFn.zig b/src/BuiltinFn.zig
index 80eb739185..20edbabe47 100644
--- a/src/BuiltinFn.zig
+++ b/src/BuiltinFn.zig
@@ -28,6 +28,7 @@ pub const Tag = enum {
     cmpxchg_weak,
     compile_error,
     compile_log,
+    const_cast,
     ctz,
     c_undef,
     c_va_arg,
@@ -75,7 +76,6 @@ pub const Tag = enum {
     prefetch,
     ptr_cast,
     ptr_to_int,
-    qual_cast,
     rem,
     return_address,
     select,
@@ -116,6 +116,7 @@ pub const Tag = enum {
     TypeOf,
     union_init,
     Vector,
+    volatile_cast,
 };
 
 pub const MemLocRequirement = enum {
@@ -346,6 +347,13 @@ pub const list = list: {
             },
         },
         .{
+            "@constCast",
+            .{
+                .tag = .const_cast,
+                .param_count = 1,
+            },
+        },
+        .{
             "@ctz",
             .{
                 .tag = .ctz,
@@ -676,13 +684,6 @@ pub const list = list: {
             },
         },
         .{
-            "@qualCast",
-            .{
-                .tag = .qual_cast,
-                .param_count = 2,
-            },
-        },
-        .{
             "@rem",
             .{
                 .tag = .rem,
@@ -964,5 +965,12 @@ pub const list = list: {
                 .param_count = 2,
             },
         },
+        .{
+            "@volatileCast",
+            .{
+                .tag = .volatile_cast,
+                .param_count = 1,
+            },
+        },
     });
 };
diff --git a/src/Cache.zig b/src/Cache.zig
deleted file mode 100644
index 3020f8e8c6..0000000000
--- a/src/Cache.zig
+++ /dev/null
@@ -1,1265 +0,0 @@
-//! Manages `zig-cache` directories.
-//! This is not a general-purpose cache. It is designed to be fast and simple,
-//! not to withstand attacks using specially-crafted input.
-
-gpa: Allocator,
-manifest_dir: fs.Dir,
-hash: HashHelper = .{},
-/// This value is accessed from multiple threads, protected by mutex.
-recent_problematic_timestamp: i128 = 0,
-mutex: std.Thread.Mutex = .{},
-
-/// A set of strings such as the zig library directory or project source root, which
-/// are stripped from the file paths before putting into the cache. They
-/// are replaced with single-character indicators. This is not to save
-/// space but to eliminate absolute file paths. This improves portability
-/// and usefulness of the cache for advanced use cases.
-prefixes_buffer: [3]Compilation.Directory = undefined,
-prefixes_len: usize = 0,
-
-const Cache = @This();
-const std = @import("std");
-const builtin = @import("builtin");
-const crypto = std.crypto;
-const fs = std.fs;
-const assert = std.debug.assert;
-const testing = std.testing;
-const mem = std.mem;
-const fmt = std.fmt;
-const Allocator = std.mem.Allocator;
-const Compilation = @import("Compilation.zig");
-const log = std.log.scoped(.cache);
-
-pub fn addPrefix(cache: *Cache, directory: Compilation.Directory) void {
-    if (directory.path) |p| {
-        log.debug("Cache.addPrefix {d} {s}", .{ cache.prefixes_len, p });
-    }
-    cache.prefixes_buffer[cache.prefixes_len] = directory;
-    cache.prefixes_len += 1;
-}
-
-/// Be sure to call `Manifest.deinit` after successful initialization.
-pub fn obtain(cache: *Cache) Manifest {
-    return Manifest{
-        .cache = cache,
-        .hash = cache.hash,
-        .manifest_file = null,
-        .manifest_dirty = false,
-        .hex_digest = undefined,
-    };
-}
-
-pub fn prefixes(cache: *const Cache) []const Compilation.Directory {
-    return cache.prefixes_buffer[0..cache.prefixes_len];
-}
-
-const PrefixedPath = struct {
-    prefix: u8,
-    sub_path: []u8,
-};
-
-fn findPrefix(cache: *const Cache, file_path: []const u8) !PrefixedPath {
-    const gpa = cache.gpa;
-    const resolved_path = try fs.path.resolve(gpa, &[_][]const u8{file_path});
-    errdefer gpa.free(resolved_path);
-    return findPrefixResolved(cache, resolved_path);
-}
-
-/// Takes ownership of `resolved_path` on success.
-fn findPrefixResolved(cache: *const Cache, resolved_path: []u8) !PrefixedPath {
-    const gpa = cache.gpa;
-    const prefixes_slice = cache.prefixes();
-    var i: u8 = 1; // Start at 1 to skip over checking the null prefix.
-    while (i < prefixes_slice.len) : (i += 1) {
-        const p = prefixes_slice[i].path.?;
-        if (mem.startsWith(u8, resolved_path, p)) {
-            // +1 to skip over the path separator here
-            const sub_path = try gpa.dupe(u8, resolved_path[p.len + 1 ..]);
-            gpa.free(resolved_path);
-            return PrefixedPath{
-                .prefix = @intCast(u8, i),
-                .sub_path = sub_path,
-            };
-        } else {
-            log.debug("'{s}' does not start with '{s}'", .{ resolved_path, p });
-        }
-    }
-
-    return PrefixedPath{
-        .prefix = 0,
-        .sub_path = resolved_path,
-    };
-}
-
-/// This is 128 bits - Even with 2^54 cache entries, the probably of a collision would be under 10^-6
-pub const bin_digest_len = 16;
-pub const hex_digest_len = bin_digest_len * 2;
-pub const BinDigest = [bin_digest_len]u8;
-
-const manifest_file_size_max = 50 * 1024 * 1024;
-
-/// The type used for hashing file contents. Currently, this is SipHash128(1, 3), because it
-/// provides enough collision resistance for the Manifest use cases, while being one of our
-/// fastest options right now.
-pub const Hasher = crypto.auth.siphash.SipHash128(1, 3);
-
-/// Initial state, that can be copied.
-pub const hasher_init: Hasher = Hasher.init(&[_]u8{0} ** Hasher.key_length);
-
-pub const File = struct {
-    prefixed_path: ?PrefixedPath,
-    max_file_size: ?usize,
-    stat: Stat,
-    bin_digest: BinDigest,
-    contents: ?[]const u8,
-
-    pub const Stat = struct {
-        inode: fs.File.INode,
-        size: u64,
-        mtime: i128,
-    };
-
-    pub fn deinit(self: *File, gpa: Allocator) void {
-        if (self.prefixed_path) |pp| {
-            gpa.free(pp.sub_path);
-            self.prefixed_path = null;
-        }
-        if (self.contents) |contents| {
-            gpa.free(contents);
-            self.contents = null;
-        }
-        self.* = undefined;
-    }
-};
-
-pub const HashHelper = struct {
-    hasher: Hasher = hasher_init,
-
-    const EmitLoc = Compilation.EmitLoc;
-
-    /// Record a slice of bytes as an dependency of the process being cached
-    pub fn addBytes(hh: *HashHelper, bytes: []const u8) void {
-        hh.hasher.update(mem.asBytes(&bytes.len));
-        hh.hasher.update(bytes);
-    }
-
-    pub fn addOptionalBytes(hh: *HashHelper, optional_bytes: ?[]const u8) void {
-        hh.add(optional_bytes != null);
-        hh.addBytes(optional_bytes orelse return);
-    }
-
-    pub fn addEmitLoc(hh: *HashHelper, emit_loc: EmitLoc) void {
-        hh.addBytes(emit_loc.basename);
-    }
-
-    pub fn addOptionalEmitLoc(hh: *HashHelper, optional_emit_loc: ?EmitLoc) void {
-        hh.add(optional_emit_loc != null);
-        hh.addEmitLoc(optional_emit_loc orelse return);
-    }
-
-    pub fn addListOfBytes(hh: *HashHelper, list_of_bytes: []const []const u8) void {
-        hh.add(list_of_bytes.len);
-        for (list_of_bytes) |bytes| hh.addBytes(bytes);
-    }
-
-    /// Convert the input value into bytes and record it as a dependency of the process being cached.
-    pub fn add(hh: *HashHelper, x: anytype) void {
-        switch (@TypeOf(x)) {
-            std.builtin.Version => {
-                hh.add(x.major);
-                hh.add(x.minor);
-                hh.add(x.patch);
-            },
-            std.Target.Os.TaggedVersionRange => {
-                switch (x) {
-                    .linux => |linux| {
-                        hh.add(linux.range.min);
-                        hh.add(linux.range.max);
-                        hh.add(linux.glibc);
-                    },
-                    .windows => |windows| {
-                        hh.add(windows.min);
-                        hh.add(windows.max);
-                    },
-                    .semver => |semver| {
-                        hh.add(semver.min);
-                        hh.add(semver.max);
-                    },
-                    .none => {},
-                }
-            },
-            else => switch (@typeInfo(@TypeOf(x))) {
-                .Bool, .Int, .Enum, .Array => hh.addBytes(mem.asBytes(&x)),
-                else => @compileError("unable to hash type " ++ @typeName(@TypeOf(x))),
-            },
-        }
-    }
-
-    pub fn addOptional(hh: *HashHelper, optional: anytype) void {
-        hh.add(optional != null);
-        hh.add(optional orelse return);
-    }
-
-    /// Returns a hex encoded hash of the inputs, without modifying state.
-    pub fn peek(hh: HashHelper) [hex_digest_len]u8 {
-        var copy = hh;
-        return copy.final();
-    }
-
-    pub fn peekBin(hh: HashHelper) BinDigest {
-        var copy = hh;
-        var bin_digest: BinDigest = undefined;
-        copy.hasher.final(&bin_digest);
-        return bin_digest;
-    }
-
-    /// Returns a hex encoded hash of the inputs, mutating the state of the hasher.
-    pub fn final(hh: *HashHelper) [hex_digest_len]u8 {
-        var bin_digest: BinDigest = undefined;
-        hh.hasher.final(&bin_digest);
-
-        var out_digest: [hex_digest_len]u8 = undefined;
-        _ = std.fmt.bufPrint(
-            &out_digest,
-            "{s}",
-            .{std.fmt.fmtSliceHexLower(&bin_digest)},
-        ) catch unreachable;
-        return out_digest;
-    }
-};
-
-pub const Lock = struct {
-    manifest_file: fs.File,
-
-    pub fn release(lock: *Lock) void {
-        if (builtin.os.tag == .windows) {
-            // Windows does not guarantee that locks are immediately unlocked when
-            // the file handle is closed. See LockFileEx documentation.
-            lock.manifest_file.unlock();
-        }
-
-        lock.manifest_file.close();
-        lock.* = undefined;
-    }
-};
-
-pub const Manifest = struct {
-    cache: *Cache,
-    /// Current state for incremental hashing.
-    hash: HashHelper,
-    manifest_file: ?fs.File,
-    manifest_dirty: bool,
-    /// Set this flag to true before calling hit() in order to indicate that
-    /// upon a cache hit, the code using the cache will not modify the files
-    /// within the cache directory. This allows multiple processes to utilize
-    /// the same cache directory at the same time.
-    want_shared_lock: bool = true,
-    have_exclusive_lock: bool = false,
-    // Indicate that we want isProblematicTimestamp to perform a filesystem write in
-    // order to obtain a problematic timestamp for the next call. Calls after that
-    // will then use the same timestamp, to avoid unnecessary filesystem writes.
-    want_refresh_timestamp: bool = true,
-    files: std.ArrayListUnmanaged(File) = .{},
-    hex_digest: [hex_digest_len]u8,
-    /// Populated when hit() returns an error because of one
-    /// of the files listed in the manifest.
-    failed_file_index: ?usize = null,
-    /// Keeps track of the last time we performed a file system write to observe
-    /// what time the file system thinks it is, according to its own granularity.
-    recent_problematic_timestamp: i128 = 0,
-
-    /// Add a file as a dependency of process being cached. When `hit` is
-    /// called, the file's contents will be checked to ensure that it matches
-    /// the contents from previous times.
-    ///
-    /// Max file size will be used to determine the amount of space the file contents
-    /// are allowed to take up in memory. If max_file_size is null, then the contents
-    /// will not be loaded into memory.
-    ///
-    /// Returns the index of the entry in the `files` array list. You can use it
-    /// to access the contents of the file after calling `hit()` like so:
-    ///
-    /// ```
-    /// var file_contents = cache_hash.files.items[file_index].contents.?;
-    /// ```
-    pub fn addFile(self: *Manifest, file_path: []const u8, max_file_size: ?usize) !usize {
-        assert(self.manifest_file == null);
-
-        const gpa = self.cache.gpa;
-        try self.files.ensureUnusedCapacity(gpa, 1);
-        const prefixed_path = try self.cache.findPrefix(file_path);
-        errdefer gpa.free(prefixed_path.sub_path);
-
-        log.debug("Manifest.addFile {s} -> {d} {s}", .{
-            file_path, prefixed_path.prefix, prefixed_path.sub_path,
-        });
-
-        self.files.addOneAssumeCapacity().* = .{
-            .prefixed_path = prefixed_path,
-            .contents = null,
-            .max_file_size = max_file_size,
-            .stat = undefined,
-            .bin_digest = undefined,
-        };
-
-        self.hash.add(prefixed_path.prefix);
-        self.hash.addBytes(prefixed_path.sub_path);
-
-        return self.files.items.len - 1;
-    }
-
-    pub fn hashCSource(self: *Manifest, c_source: Compilation.CSourceFile) !void {
-        _ = try self.addFile(c_source.src_path, null);
-        // Hash the extra flags, with special care to call addFile for file parameters.
-        // TODO this logic can likely be improved by utilizing clang_options_data.zig.
-        const file_args = [_][]const u8{"-include"};
-        var arg_i: usize = 0;
-        while (arg_i < c_source.extra_flags.len) : (arg_i += 1) {
-            const arg = c_source.extra_flags[arg_i];
-            self.hash.addBytes(arg);
-            for (file_args) |file_arg| {
-                if (mem.eql(u8, file_arg, arg) and arg_i + 1 < c_source.extra_flags.len) {
-                    arg_i += 1;
-                    _ = try self.addFile(c_source.extra_flags[arg_i], null);
-                }
-            }
-        }
-    }
-
-    pub fn addOptionalFile(self: *Manifest, optional_file_path: ?[]const u8) !void {
-        self.hash.add(optional_file_path != null);
-        const file_path = optional_file_path orelse return;
-        _ = try self.addFile(file_path, null);
-    }
-
-    pub fn addListOfFiles(self: *Manifest, list_of_files: []const []const u8) !void {
-        self.hash.add(list_of_files.len);
-        for (list_of_files) |file_path| {
-            _ = try self.addFile(file_path, null);
-        }
-    }
-
-    /// Check the cache to see if the input exists in it. If it exists, returns `true`.
-    /// A hex encoding of its hash is available by calling `final`.
-    ///
-    /// This function will also acquire an exclusive lock to the manifest file. This means
-    /// that a process holding a Manifest will block any other process attempting to
-    /// acquire the lock. If `want_shared_lock` is `true`, a cache hit guarantees the
-    /// manifest file to be locked in shared mode, and a cache miss guarantees the manifest
-    /// file to be locked in exclusive mode.
-    ///
-    /// The lock on the manifest file is released when `deinit` is called. As another
-    /// option, one may call `toOwnedLock` to obtain a smaller object which can represent
-    /// the lock. `deinit` is safe to call whether or not `toOwnedLock` has been called.
-    pub fn hit(self: *Manifest) !bool {
-        const gpa = self.cache.gpa;
-        assert(self.manifest_file == null);
-
-        self.failed_file_index = null;
-
-        const ext = ".txt";
-        var manifest_file_path: [self.hex_digest.len + ext.len]u8 = undefined;
-
-        var bin_digest: BinDigest = undefined;
-        self.hash.hasher.final(&bin_digest);
-
-        _ = std.fmt.bufPrint(
-            &self.hex_digest,
-            "{s}",
-            .{std.fmt.fmtSliceHexLower(&bin_digest)},
-        ) catch unreachable;
-
-        self.hash.hasher = hasher_init;
-        self.hash.hasher.update(&bin_digest);
-
-        mem.copy(u8, &manifest_file_path, &self.hex_digest);
-        manifest_file_path[self.hex_digest.len..][0..ext.len].* = ext.*;
-
-        if (self.files.items.len == 0) {
-            // If there are no file inputs, we check if the manifest file exists instead of
-            // comparing the hashes on the files used for the cached item
-            while (true) {
-                if (self.cache.manifest_dir.openFile(&manifest_file_path, .{
-                    .mode = .read_write,
-                    .lock = .Exclusive,
-                    .lock_nonblocking = self.want_shared_lock,
-                })) |manifest_file| {
-                    self.manifest_file = manifest_file;
-                    self.have_exclusive_lock = true;
-                    break;
-                } else |open_err| switch (open_err) {
-                    error.WouldBlock => {
-                        self.manifest_file = try self.cache.manifest_dir.openFile(&manifest_file_path, .{
-                            .lock = .Shared,
-                        });
-                        break;
-                    },
-                    error.FileNotFound => {
-                        if (self.cache.manifest_dir.createFile(&manifest_file_path, .{
-                            .read = true,
-                            .truncate = false,
-                            .lock = .Exclusive,
-                            .lock_nonblocking = self.want_shared_lock,
-                        })) |manifest_file| {
-                            self.manifest_file = manifest_file;
-                            self.manifest_dirty = true;
-                            self.have_exclusive_lock = true;
-                            return false; // cache miss; exclusive lock already held
-                        } else |err| switch (err) {
-                            error.WouldBlock => continue,
-                            else => |e| return e,
-                        }
-                    },
-                    else => |e| return e,
-                }
-            }
-        } else {
-            if (self.cache.manifest_dir.createFile(&manifest_file_path, .{
-                .read = true,
-                .truncate = false,
-                .lock = .Exclusive,
-                .lock_nonblocking = self.want_shared_lock,
-            })) |manifest_file| {
-                self.manifest_file = manifest_file;
-                self.have_exclusive_lock = true;
-            } else |err| switch (err) {
-                error.WouldBlock => {
-                    self.manifest_file = try self.cache.manifest_dir.openFile(&manifest_file_path, .{
-                        .lock = .Shared,
-                    });
-                },
-                else => |e| return e,
-            }
-        }
-
-        self.want_refresh_timestamp = true;
-
-        const file_contents = try self.manifest_file.?.reader().readAllAlloc(gpa, manifest_file_size_max);
-        defer gpa.free(file_contents);
-
-        const input_file_count = self.files.items.len;
-        var any_file_changed = false;
-        var line_iter = mem.tokenize(u8, file_contents, "\n");
-        var idx: usize = 0;
-        while (line_iter.next()) |line| {
-            defer idx += 1;
-
-            const cache_hash_file = if (idx < input_file_count) &self.files.items[idx] else blk: {
-                const new = try self.files.addOne(gpa);
-                new.* = .{
-                    .prefixed_path = null,
-                    .contents = null,
-                    .max_file_size = null,
-                    .stat = undefined,
-                    .bin_digest = undefined,
-                };
-                break :blk new;
-            };
-
-            var iter = mem.tokenize(u8, line, " ");
-            const size = iter.next() orelse return error.InvalidFormat;
-            const inode = iter.next() orelse return error.InvalidFormat;
-            const mtime_nsec_str = iter.next() orelse return error.InvalidFormat;
-            const digest_str = iter.next() orelse return error.InvalidFormat;
-            const prefix_str = iter.next() orelse return error.InvalidFormat;
-            const file_path = iter.rest();
-
-            cache_hash_file.stat.size = fmt.parseInt(u64, size, 10) catch return error.InvalidFormat;
-            cache_hash_file.stat.inode = fmt.parseInt(fs.File.INode, inode, 10) catch return error.InvalidFormat;
-            cache_hash_file.stat.mtime = fmt.parseInt(i64, mtime_nsec_str, 10) catch return error.InvalidFormat;
-            _ = std.fmt.hexToBytes(&cache_hash_file.bin_digest, digest_str) catch return error.InvalidFormat;
-            const prefix = fmt.parseInt(u8, prefix_str, 10) catch return error.InvalidFormat;
-            if (prefix >= self.cache.prefixes_len) return error.InvalidFormat;
-
-            if (file_path.len == 0) {
-                return error.InvalidFormat;
-            }
-            if (cache_hash_file.prefixed_path) |pp| {
-                if (pp.prefix != prefix or !mem.eql(u8, file_path, pp.sub_path)) {
-                    return error.InvalidFormat;
-                }
-            }
-
-            if (cache_hash_file.prefixed_path == null) {
-                cache_hash_file.prefixed_path = .{
-                    .prefix = prefix,
-                    .sub_path = try gpa.dupe(u8, file_path),
-                };
-            }
-
-            const pp = cache_hash_file.prefixed_path.?;
-            const dir = self.cache.prefixes()[pp.prefix].handle;
-            const this_file = dir.openFile(pp.sub_path, .{ .mode = .read_only }) catch |err| switch (err) {
-                error.FileNotFound => {
-                    try self.upgradeToExclusiveLock();
-                    return false;
-                },
-                else => return error.CacheUnavailable,
-            };
-            defer this_file.close();
-
-            const actual_stat = this_file.stat() catch |err| {
-                self.failed_file_index = idx;
-                return err;
-            };
-            const size_match = actual_stat.size == cache_hash_file.stat.size;
-            const mtime_match = actual_stat.mtime == cache_hash_file.stat.mtime;
-            const inode_match = actual_stat.inode == cache_hash_file.stat.inode;
-
-            if (!size_match or !mtime_match or !inode_match) {
-                self.manifest_dirty = true;
-
-                cache_hash_file.stat = .{
-                    .size = actual_stat.size,
-                    .mtime = actual_stat.mtime,
-                    .inode = actual_stat.inode,
-                };
-
-                if (self.isProblematicTimestamp(cache_hash_file.stat.mtime)) {
-                    // The actual file has an unreliable timestamp, force it to be hashed
-                    cache_hash_file.stat.mtime = 0;
-                    cache_hash_file.stat.inode = 0;
-                }
-
-                var actual_digest: BinDigest = undefined;
-                hashFile(this_file, &actual_digest) catch |err| {
-                    self.failed_file_index = idx;
-                    return err;
-                };
-
-                if (!mem.eql(u8, &cache_hash_file.bin_digest, &actual_digest)) {
-                    cache_hash_file.bin_digest = actual_digest;
-                    // keep going until we have the input file digests
-                    any_file_changed = true;
-                }
-            }
-
-            if (!any_file_changed) {
-                self.hash.hasher.update(&cache_hash_file.bin_digest);
-            }
-        }
-
-        if (any_file_changed) {
-            // cache miss
-            // keep the manifest file open
-            self.unhit(bin_digest, input_file_count);
-            try self.upgradeToExclusiveLock();
-            return false;
-        }
-
-        if (idx < input_file_count) {
-            self.manifest_dirty = true;
-            while (idx < input_file_count) : (idx += 1) {
-                const ch_file = &self.files.items[idx];
-                self.populateFileHash(ch_file) catch |err| {
-                    self.failed_file_index = idx;
-                    return err;
-                };
-            }
-            try self.upgradeToExclusiveLock();
-            return false;
-        }
-
-        if (self.want_shared_lock) {
-            try self.downgradeToSharedLock();
-        }
-
-        return true;
-    }
-
-    pub fn unhit(self: *Manifest, bin_digest: BinDigest, input_file_count: usize) void {
-        // Reset the hash.
-        self.hash.hasher = hasher_init;
-        self.hash.hasher.update(&bin_digest);
-
-        // Remove files not in the initial hash.
-        for (self.files.items[input_file_count..]) |*file| {
-            file.deinit(self.cache.gpa);
-        }
-        self.files.shrinkRetainingCapacity(input_file_count);
-
-        for (self.files.items) |file| {
-            self.hash.hasher.update(&file.bin_digest);
-        }
-    }
-
-    fn isProblematicTimestamp(man: *Manifest, file_time: i128) bool {
-        // If the file_time is prior to the most recent problematic timestamp
-        // then we don't need to access the filesystem.
-        if (file_time < man.recent_problematic_timestamp)
-            return false;
-
-        // Next we will check the globally shared Cache timestamp, which is accessed
-        // from multiple threads.
-        man.cache.mutex.lock();
-        defer man.cache.mutex.unlock();
-
-        // Save the global one to our local one to avoid locking next time.
-        man.recent_problematic_timestamp = man.cache.recent_problematic_timestamp;
-        if (file_time < man.recent_problematic_timestamp)
-            return false;
-
-        // This flag prevents multiple filesystem writes for the same hit() call.
-        if (man.want_refresh_timestamp) {
-            man.want_refresh_timestamp = false;
-
-            var file = man.cache.manifest_dir.createFile("timestamp", .{
-                .read = true,
-                .truncate = true,
-            }) catch return true;
-            defer file.close();
-
-            // Save locally and also save globally (we still hold the global lock).
-            man.recent_problematic_timestamp = (file.stat() catch return true).mtime;
-            man.cache.recent_problematic_timestamp = man.recent_problematic_timestamp;
-        }
-
-        return file_time >= man.recent_problematic_timestamp;
-    }
-
-    fn populateFileHash(self: *Manifest, ch_file: *File) !void {
-        const pp = ch_file.prefixed_path.?;
-        const dir = self.cache.prefixes()[pp.prefix].handle;
-        const file = try dir.openFile(pp.sub_path, .{});
-        defer file.close();
-
-        const actual_stat = try file.stat();
-        ch_file.stat = .{
-            .size = actual_stat.size,
-            .mtime = actual_stat.mtime,
-            .inode = actual_stat.inode,
-        };
-
-        if (self.isProblematicTimestamp(ch_file.stat.mtime)) {
-            // The actual file has an unreliable timestamp, force it to be hashed
-            ch_file.stat.mtime = 0;
-            ch_file.stat.inode = 0;
-        }
-
-        if (ch_file.max_file_size) |max_file_size| {
-            if (ch_file.stat.size > max_file_size) {
-                return error.FileTooBig;
-            }
-
-            const contents = try self.cache.gpa.alloc(u8, @intCast(usize, ch_file.stat.size));
-            errdefer self.cache.gpa.free(contents);
-
-            // Hash while reading from disk, to keep the contents in the cpu cache while
-            // doing hashing.
-            var hasher = hasher_init;
-            var off: usize = 0;
-            while (true) {
-                // give me everything you've got, captain
-                const bytes_read = try file.read(contents[off..]);
-                if (bytes_read == 0) break;
-                hasher.update(contents[off..][0..bytes_read]);
-                off += bytes_read;
-            }
-            hasher.final(&ch_file.bin_digest);
-
-            ch_file.contents = contents;
-        } else {
-            try hashFile(file, &ch_file.bin_digest);
-        }
-
-        self.hash.hasher.update(&ch_file.bin_digest);
-    }
-
-    /// Add a file as a dependency of process being cached, after the initial hash has been
-    /// calculated. This is useful for processes that don't know all the files that
-    /// are depended on ahead of time. For example, a source file that can import other files
-    /// will need to be recompiled if the imported file is changed.
-    pub fn addFilePostFetch(self: *Manifest, file_path: []const u8, max_file_size: usize) ![]const u8 {
-        assert(self.manifest_file != null);
-
-        const gpa = self.cache.gpa;
-        const prefixed_path = try self.cache.findPrefix(file_path);
-        errdefer gpa.free(prefixed_path.sub_path);
-
-        log.debug("Manifest.addFilePostFetch {s} -> {d} {s}", .{
-            file_path, prefixed_path.prefix, prefixed_path.sub_path,
-        });
-
-        const new_ch_file = try self.files.addOne(gpa);
-        new_ch_file.* = .{
-            .prefixed_path = prefixed_path,
-            .max_file_size = max_file_size,
-            .stat = undefined,
-            .bin_digest = undefined,
-            .contents = null,
-        };
-        errdefer self.files.shrinkRetainingCapacity(self.files.items.len - 1);
-
-        try self.populateFileHash(new_ch_file);
-
-        return new_ch_file.contents.?;
-    }
-
-    /// Add a file as a dependency of process being cached, after the initial hash has been
-    /// calculated. This is useful for processes that don't know the all the files that
-    /// are depended on ahead of time. For example, a source file that can import other files
-    /// will need to be recompiled if the imported file is changed.
-    pub fn addFilePost(self: *Manifest, file_path: []const u8) !void {
-        assert(self.manifest_file != null);
-
-        const gpa = self.cache.gpa;
-        const prefixed_path = try self.cache.findPrefix(file_path);
-        errdefer gpa.free(prefixed_path.sub_path);
-
-        log.debug("Manifest.addFilePost {s} -> {d} {s}", .{
-            file_path, prefixed_path.prefix, prefixed_path.sub_path,
-        });
-
-        const new_ch_file = try self.files.addOne(gpa);
-        new_ch_file.* = .{
-            .prefixed_path = prefixed_path,
-            .max_file_size = null,
-            .stat = undefined,
-            .bin_digest = undefined,
-            .contents = null,
-        };
-        errdefer self.files.shrinkRetainingCapacity(self.files.items.len - 1);
-
-        try self.populateFileHash(new_ch_file);
-    }
-
-    /// Like `addFilePost` but when the file contents have already been loaded from disk.
-    /// On success, cache takes ownership of `resolved_path`.
-    pub fn addFilePostContents(
-        self: *Manifest,
-        resolved_path: []u8,
-        bytes: []const u8,
-        stat: File.Stat,
-    ) error{OutOfMemory}!void {
-        assert(self.manifest_file != null);
-        const gpa = self.cache.gpa;
-
-        const ch_file = try self.files.addOne(gpa);
-        errdefer self.files.shrinkRetainingCapacity(self.files.items.len - 1);
-
-        log.debug("Manifest.addFilePostContents resolved_path={s}", .{resolved_path});
-
-        const prefixed_path = try self.cache.findPrefixResolved(resolved_path);
-        errdefer gpa.free(prefixed_path.sub_path);
-
-        log.debug("Manifest.addFilePostContents -> {d} {s}", .{
-            prefixed_path.prefix, prefixed_path.sub_path,
-        });
-
-        ch_file.* = .{
-            .prefixed_path = prefixed_path,
-            .max_file_size = null,
-            .stat = stat,
-            .bin_digest = undefined,
-            .contents = null,
-        };
-
-        if (self.isProblematicTimestamp(ch_file.stat.mtime)) {
-            // The actual file has an unreliable timestamp, force it to be hashed
-            ch_file.stat.mtime = 0;
-            ch_file.stat.inode = 0;
-        }
-
-        {
-            var hasher = hasher_init;
-            hasher.update(bytes);
-            hasher.final(&ch_file.bin_digest);
-        }
-
-        self.hash.hasher.update(&ch_file.bin_digest);
-    }
-
-    pub fn addDepFilePost(self: *Manifest, dir: fs.Dir, dep_file_basename: []const u8) !void {
-        assert(self.manifest_file != null);
-
-        const dep_file_contents = try dir.readFileAlloc(self.cache.gpa, dep_file_basename, manifest_file_size_max);
-        defer self.cache.gpa.free(dep_file_contents);
-
-        var error_buf = std.ArrayList(u8).init(self.cache.gpa);
-        defer error_buf.deinit();
-
-        var it: @import("DepTokenizer.zig") = .{ .bytes = dep_file_contents };
-
-        // Skip first token: target.
-        switch (it.next() orelse return) { // Empty dep file OK.
-            .target, .target_must_resolve, .prereq => {},
-            else => |err| {
-                try err.printError(error_buf.writer());
-                log.err("failed parsing {s}: {s}", .{ dep_file_basename, error_buf.items });
-                return error.InvalidDepFile;
-            },
-        }
-        // Process 0+ preqreqs.
-        // Clang is invoked in single-source mode so we never get more targets.
-        while (true) {
-            switch (it.next() orelse return) {
-                .target, .target_must_resolve => return,
-                .prereq => |file_path| try self.addFilePost(file_path),
-                else => |err| {
-                    try err.printError(error_buf.writer());
-                    log.err("failed parsing {s}: {s}", .{ dep_file_basename, error_buf.items });
-                    return error.InvalidDepFile;
-                },
-            }
-        }
-    }
-
-    /// Returns a hex encoded hash of the inputs.
-    pub fn final(self: *Manifest) [hex_digest_len]u8 {
-        assert(self.manifest_file != null);
-
-        // We don't close the manifest file yet, because we want to
-        // keep it locked until the API user is done using it.
-        // We also don't write out the manifest yet, because until
-        // cache_release is called we still might be working on creating
-        // the artifacts to cache.
-
-        var bin_digest: BinDigest = undefined;
-        self.hash.hasher.final(&bin_digest);
-
-        var out_digest: [hex_digest_len]u8 = undefined;
-        _ = std.fmt.bufPrint(
-            &out_digest,
-            "{s}",
-            .{std.fmt.fmtSliceHexLower(&bin_digest)},
-        ) catch unreachable;
-
-        return out_digest;
-    }
-
-    /// If `want_shared_lock` is true, this function automatically downgrades the
-    /// lock from exclusive to shared.
-    pub fn writeManifest(self: *Manifest) !void {
-        assert(self.have_exclusive_lock);
-
-        const manifest_file = self.manifest_file.?;
-        if (self.manifest_dirty) {
-            self.manifest_dirty = false;
-
-            var contents = std.ArrayList(u8).init(self.cache.gpa);
-            defer contents.deinit();
-
-            const writer = contents.writer();
-            var encoded_digest: [hex_digest_len]u8 = undefined;
-
-            for (self.files.items) |file| {
-                _ = std.fmt.bufPrint(
-                    &encoded_digest,
-                    "{s}",
-                    .{std.fmt.fmtSliceHexLower(&file.bin_digest)},
-                ) catch unreachable;
-                try writer.print("{d} {d} {d} {s} {d} {s}\n", .{
-                    file.stat.size,
-                    file.stat.inode,
-                    file.stat.mtime,
-                    &encoded_digest,
-                    file.prefixed_path.?.prefix,
-                    file.prefixed_path.?.sub_path,
-                });
-            }
-
-            try manifest_file.setEndPos(contents.items.len);
-            try manifest_file.pwriteAll(contents.items, 0);
-        }
-
-        if (self.want_shared_lock) {
-            try self.downgradeToSharedLock();
-        }
-    }
-
-    fn downgradeToSharedLock(self: *Manifest) !void {
-        if (!self.have_exclusive_lock) return;
-
-        // WASI does not currently support flock, so we bypass it here.
-        // TODO: If/when flock is supported on WASI, this check should be removed.
-        //       See https://github.com/WebAssembly/wasi-filesystem/issues/2
-        if (builtin.os.tag != .wasi or std.process.can_spawn or !builtin.single_threaded) {
-            const manifest_file = self.manifest_file.?;
-            try manifest_file.downgradeLock();
-        }
-
-        self.have_exclusive_lock = false;
-    }
-
-    fn upgradeToExclusiveLock(self: *Manifest) !void {
-        if (self.have_exclusive_lock) return;
-        assert(self.manifest_file != null);
-
-        // WASI does not currently support flock, so we bypass it here.
-        // TODO: If/when flock is supported on WASI, this check should be removed.
-        //       See https://github.com/WebAssembly/wasi-filesystem/issues/2
-        if (builtin.os.tag != .wasi or std.process.can_spawn or !builtin.single_threaded) {
-            const manifest_file = self.manifest_file.?;
-            // Here we intentionally have a period where the lock is released, in case there are
-            // other processes holding a shared lock.
-            manifest_file.unlock();
-            try manifest_file.lock(.Exclusive);
-        }
-        self.have_exclusive_lock = true;
-    }
-
-    /// Obtain only the data needed to maintain a lock on the manifest file.
-    /// The `Manifest` remains safe to deinit.
-    /// Don't forget to call `writeManifest` before this!
-    pub fn toOwnedLock(self: *Manifest) Lock {
-        const lock: Lock = .{
-            .manifest_file = self.manifest_file.?,
-        };
-
-        self.manifest_file = null;
-        return lock;
-    }
-
-    /// Releases the manifest file and frees any memory the Manifest was using.
-    /// `Manifest.hit` must be called first.
-    /// Don't forget to call `writeManifest` before this!
-    pub fn deinit(self: *Manifest) void {
-        if (self.manifest_file) |file| {
-            if (builtin.os.tag == .windows) {
-                // See Lock.release for why this is required on Windows
-                file.unlock();
-            }
-
-            file.close();
-        }
-        for (self.files.items) |*file| {
-            file.deinit(self.cache.gpa);
-        }
-        self.files.deinit(self.cache.gpa);
-    }
-};
-
-/// On operating systems that support symlinks, does a readlink. On other operating systems,
-/// uses the file contents. Windows supports symlinks but only with elevated privileges, so
-/// it is treated as not supporting symlinks.
-pub fn readSmallFile(dir: fs.Dir, sub_path: []const u8, buffer: []u8) ![]u8 {
-    if (builtin.os.tag == .windows) {
-        return dir.readFile(sub_path, buffer);
-    } else {
-        return dir.readLink(sub_path, buffer);
-    }
-}
-
-/// On operating systems that support symlinks, does a symlink. On other operating systems,
-/// uses the file contents. Windows supports symlinks but only with elevated privileges, so
-/// it is treated as not supporting symlinks.
-/// `data` must be a valid UTF-8 encoded file path and 255 bytes or fewer.
-pub fn writeSmallFile(dir: fs.Dir, sub_path: []const u8, data: []const u8) !void {
-    assert(data.len <= 255);
-    if (builtin.os.tag == .windows) {
-        return dir.writeFile(sub_path, data);
-    } else {
-        return dir.symLink(data, sub_path, .{});
-    }
-}
-
-fn hashFile(file: fs.File, bin_digest: *[Hasher.mac_length]u8) !void {
-    var buf: [1024]u8 = undefined;
-
-    var hasher = hasher_init;
-    while (true) {
-        const bytes_read = try file.read(&buf);
-        if (bytes_read == 0) break;
-        hasher.update(buf[0..bytes_read]);
-    }
-
-    hasher.final(bin_digest);
-}
-
-// Create/Write a file, close it, then grab its stat.mtime timestamp.
-fn testGetCurrentFileTimestamp() !i128 {
-    var file = try fs.cwd().createFile("test-filetimestamp.tmp", .{
-        .read = true,
-        .truncate = true,
-    });
-    defer file.close();
-
-    return (try file.stat()).mtime;
-}
-
-test "cache file and then recall it" {
-    if (builtin.os.tag == .wasi) {
-        // https://github.com/ziglang/zig/issues/5437
-        return error.SkipZigTest;
-    }
-
-    const cwd = fs.cwd();
-
-    const temp_file = "test.txt";
-    const temp_manifest_dir = "temp_manifest_dir";
-
-    try cwd.writeFile(temp_file, "Hello, world!\n");
-
-    // Wait for file timestamps to tick
-    const initial_time = try testGetCurrentFileTimestamp();
-    while ((try testGetCurrentFileTimestamp()) == initial_time) {
-        std.time.sleep(1);
-    }
-
-    var digest1: [hex_digest_len]u8 = undefined;
-    var digest2: [hex_digest_len]u8 = undefined;
-
-    {
-        var cache = Cache{
-            .gpa = testing.allocator,
-            .manifest_dir = try cwd.makeOpenPath(temp_manifest_dir, .{}),
-        };
-        cache.addPrefix(.{ .path = null, .handle = fs.cwd() });
-        defer cache.manifest_dir.close();
-
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.add(true);
-            ch.hash.add(@as(u16, 1234));
-            ch.hash.addBytes("1234");
-            _ = try ch.addFile(temp_file, null);
-
-            // There should be nothing in the cache
-            try testing.expectEqual(false, try ch.hit());
-
-            digest1 = ch.final();
-            try ch.writeManifest();
-        }
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.add(true);
-            ch.hash.add(@as(u16, 1234));
-            ch.hash.addBytes("1234");
-            _ = try ch.addFile(temp_file, null);
-
-            // Cache hit! We just "built" the same file
-            try testing.expect(try ch.hit());
-            digest2 = ch.final();
-
-            try testing.expectEqual(false, ch.have_exclusive_lock);
-        }
-
-        try testing.expectEqual(digest1, digest2);
-    }
-
-    try cwd.deleteTree(temp_manifest_dir);
-    try cwd.deleteFile(temp_file);
-}
-
-test "check that changing a file makes cache fail" {
-    if (builtin.os.tag == .wasi) {
-        // https://github.com/ziglang/zig/issues/5437
-        return error.SkipZigTest;
-    }
-    const cwd = fs.cwd();
-
-    const temp_file = "cache_hash_change_file_test.txt";
-    const temp_manifest_dir = "cache_hash_change_file_manifest_dir";
-    const original_temp_file_contents = "Hello, world!\n";
-    const updated_temp_file_contents = "Hello, world; but updated!\n";
-
-    try cwd.deleteTree(temp_manifest_dir);
-    try cwd.deleteTree(temp_file);
-
-    try cwd.writeFile(temp_file, original_temp_file_contents);
-
-    // Wait for file timestamps to tick
-    const initial_time = try testGetCurrentFileTimestamp();
-    while ((try testGetCurrentFileTimestamp()) == initial_time) {
-        std.time.sleep(1);
-    }
-
-    var digest1: [hex_digest_len]u8 = undefined;
-    var digest2: [hex_digest_len]u8 = undefined;
-
-    {
-        var cache = Cache{
-            .gpa = testing.allocator,
-            .manifest_dir = try cwd.makeOpenPath(temp_manifest_dir, .{}),
-        };
-        cache.addPrefix(.{ .path = null, .handle = fs.cwd() });
-        defer cache.manifest_dir.close();
-
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.addBytes("1234");
-            const temp_file_idx = try ch.addFile(temp_file, 100);
-
-            // There should be nothing in the cache
-            try testing.expectEqual(false, try ch.hit());
-
-            try testing.expect(mem.eql(u8, original_temp_file_contents, ch.files.items[temp_file_idx].contents.?));
-
-            digest1 = ch.final();
-
-            try ch.writeManifest();
-        }
-
-        try cwd.writeFile(temp_file, updated_temp_file_contents);
-
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.addBytes("1234");
-            const temp_file_idx = try ch.addFile(temp_file, 100);
-
-            // A file that we depend on has been updated, so the cache should not contain an entry for it
-            try testing.expectEqual(false, try ch.hit());
-
-            // The cache system does not keep the contents of re-hashed input files.
-            try testing.expect(ch.files.items[temp_file_idx].contents == null);
-
-            digest2 = ch.final();
-
-            try ch.writeManifest();
-        }
-
-        try testing.expect(!mem.eql(u8, digest1[0..], digest2[0..]));
-    }
-
-    try cwd.deleteTree(temp_manifest_dir);
-    try cwd.deleteTree(temp_file);
-}
-
-test "no file inputs" {
-    if (builtin.os.tag == .wasi) {
-        // https://github.com/ziglang/zig/issues/5437
-        return error.SkipZigTest;
-    }
-    const cwd = fs.cwd();
-    const temp_manifest_dir = "no_file_inputs_manifest_dir";
-    defer cwd.deleteTree(temp_manifest_dir) catch {};
-
-    var digest1: [hex_digest_len]u8 = undefined;
-    var digest2: [hex_digest_len]u8 = undefined;
-
-    var cache = Cache{
-        .gpa = testing.allocator,
-        .manifest_dir = try cwd.makeOpenPath(temp_manifest_dir, .{}),
-    };
-    cache.addPrefix(.{ .path = null, .handle = fs.cwd() });
-    defer cache.manifest_dir.close();
-
-    {
-        var man = cache.obtain();
-        defer man.deinit();
-
-        man.hash.addBytes("1234");
-
-        // There should be nothing in the cache
-        try testing.expectEqual(false, try man.hit());
-
-        digest1 = man.final();
-
-        try man.writeManifest();
-    }
-    {
-        var man = cache.obtain();
-        defer man.deinit();
-
-        man.hash.addBytes("1234");
-
-        try testing.expect(try man.hit());
-        digest2 = man.final();
-        try testing.expectEqual(false, man.have_exclusive_lock);
-    }
-
-    try testing.expectEqual(digest1, digest2);
-}
-
-test "Manifest with files added after initial hash work" {
-    if (builtin.os.tag == .wasi) {
-        // https://github.com/ziglang/zig/issues/5437
-        return error.SkipZigTest;
-    }
-    const cwd = fs.cwd();
-
-    const temp_file1 = "cache_hash_post_file_test1.txt";
-    const temp_file2 = "cache_hash_post_file_test2.txt";
-    const temp_manifest_dir = "cache_hash_post_file_manifest_dir";
-
-    try cwd.writeFile(temp_file1, "Hello, world!\n");
-    try cwd.writeFile(temp_file2, "Hello world the second!\n");
-
-    // Wait for file timestamps to tick
-    const initial_time = try testGetCurrentFileTimestamp();
-    while ((try testGetCurrentFileTimestamp()) == initial_time) {
-        std.time.sleep(1);
-    }
-
-    var digest1: [hex_digest_len]u8 = undefined;
-    var digest2: [hex_digest_len]u8 = undefined;
-    var digest3: [hex_digest_len]u8 = undefined;
-
-    {
-        var cache = Cache{
-            .gpa = testing.allocator,
-            .manifest_dir = try cwd.makeOpenPath(temp_manifest_dir, .{}),
-        };
-        cache.addPrefix(.{ .path = null, .handle = fs.cwd() });
-        defer cache.manifest_dir.close();
-
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.addBytes("1234");
-            _ = try ch.addFile(temp_file1, null);
-
-            // There should be nothing in the cache
-            try testing.expectEqual(false, try ch.hit());
-
-            _ = try ch.addFilePost(temp_file2);
-
-            digest1 = ch.final();
-            try ch.writeManifest();
-        }
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.addBytes("1234");
-            _ = try ch.addFile(temp_file1, null);
-
-            try testing.expect(try ch.hit());
-            digest2 = ch.final();
-
-            try testing.expectEqual(false, ch.have_exclusive_lock);
-        }
-        try testing.expect(mem.eql(u8, &digest1, &digest2));
-
-        // Modify the file added after initial hash
-        try cwd.writeFile(temp_file2, "Hello world the second, updated\n");
-
-        // Wait for file timestamps to tick
-        const initial_time2 = try testGetCurrentFileTimestamp();
-        while ((try testGetCurrentFileTimestamp()) == initial_time2) {
-            std.time.sleep(1);
-        }
-
-        {
-            var ch = cache.obtain();
-            defer ch.deinit();
-
-            ch.hash.addBytes("1234");
-            _ = try ch.addFile(temp_file1, null);
-
-            // A file that we depend on has been updated, so the cache should not contain an entry for it
-            try testing.expectEqual(false, try ch.hit());
-
-            _ = try ch.addFilePost(temp_file2);
-
-            digest3 = ch.final();
-
-            try ch.writeManifest();
-        }
-
-        try testing.expect(!mem.eql(u8, &digest1, &digest3));
-    }
-
-    try cwd.deleteTree(temp_manifest_dir);
-    try cwd.deleteFile(temp_file1);
-    try cwd.deleteFile(temp_file2);
-}
diff --git a/src/Compilation.zig b/src/Compilation.zig
index 2aae38c260..44201ab834 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -26,7 +26,7 @@ const wasi_libc = @import("wasi_libc.zig");
 const fatal = @import("main.zig").fatal;
 const clangMain = @import("main.zig").clangMain;
 const Module = @import("Module.zig");
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 const translate_c = @import("translate_c.zig");
 const clang = @import("clang.zig");
 const c_codegen = @import("codegen/c.zig");
@@ -807,44 +807,7 @@ pub const AllErrors = struct {
     }
 };
 
-pub const Directory = struct {
-    /// This field is redundant for operations that can act on the open directory handle
-    /// directly, but it is needed when passing the directory to a child process.
-    /// `null` means cwd.
-    path: ?[]const u8,
-    handle: std.fs.Dir,
-
-    pub fn join(self: Directory, allocator: Allocator, paths: []const []const u8) ![]u8 {
-        if (self.path) |p| {
-            // TODO clean way to do this with only 1 allocation
-            const part2 = try std.fs.path.join(allocator, paths);
-            defer allocator.free(part2);
-            return std.fs.path.join(allocator, &[_][]const u8{ p, part2 });
-        } else {
-            return std.fs.path.join(allocator, paths);
-        }
-    }
-
-    pub fn joinZ(self: Directory, allocator: Allocator, paths: []const []const u8) ![:0]u8 {
-        if (self.path) |p| {
-            // TODO clean way to do this with only 1 allocation
-            const part2 = try std.fs.path.join(allocator, paths);
-            defer allocator.free(part2);
-            return std.fs.path.joinZ(allocator, &[_][]const u8{ p, part2 });
-        } else {
-            return std.fs.path.joinZ(allocator, paths);
-        }
-    }
-
-    /// Whether or not the handle should be closed, or the path should be freed
-    /// is determined by usage, however this function is provided for convenience
-    /// if it happens to be what the caller needs.
-    pub fn closeAndFree(self: *Directory, gpa: Allocator) void {
-        self.handle.close();
-        if (self.path) |p| gpa.free(p);
-        self.* = undefined;
-    }
-};
+pub const Directory = Cache.Directory;
 
 pub const EmitLoc = struct {
     /// If this is `null` it means the file will be output to the cache directory.
@@ -854,6 +817,35 @@ pub const EmitLoc = struct {
     basename: []const u8,
 };
 
+pub const cache_helpers = struct {
+    pub fn addEmitLoc(hh: *Cache.HashHelper, emit_loc: EmitLoc) void {
+        hh.addBytes(emit_loc.basename);
+    }
+
+    pub fn addOptionalEmitLoc(hh: *Cache.HashHelper, optional_emit_loc: ?EmitLoc) void {
+        hh.add(optional_emit_loc != null);
+        addEmitLoc(hh, optional_emit_loc orelse return);
+    }
+
+    pub fn hashCSource(self: *Cache.Manifest, c_source: Compilation.CSourceFile) !void {
+        _ = try self.addFile(c_source.src_path, null);
+        // Hash the extra flags, with special care to call addFile for file parameters.
+        // TODO this logic can likely be improved by utilizing clang_options_data.zig.
+        const file_args = [_][]const u8{"-include"};
+        var arg_i: usize = 0;
+        while (arg_i < c_source.extra_flags.len) : (arg_i += 1) {
+            const arg = c_source.extra_flags[arg_i];
+            self.hash.addBytes(arg);
+            for (file_args) |file_arg| {
+                if (mem.eql(u8, file_arg, arg) and arg_i + 1 < c_source.extra_flags.len) {
+                    arg_i += 1;
+                    _ = try self.addFile(c_source.extra_flags[arg_i], null);
+                }
+            }
+        }
+    }
+};
+
 pub const ClangPreprocessorMode = enum {
     no,
     /// This means we are doing `zig cc -E -o <path>`.
@@ -997,6 +989,7 @@ pub const InitOptions = struct {
     linker_optimization: ?u8 = null,
     linker_compress_debug_sections: ?link.CompressDebugSections = null,
     linker_module_definition_file: ?[]const u8 = null,
+    linker_sort_section: ?link.SortSection = null,
     major_subsystem_version: ?u32 = null,
     minor_subsystem_version: ?u32 = null,
     clang_passthrough_mode: bool = false,
@@ -1029,6 +1022,7 @@ pub const InitOptions = struct {
     /// This is for stage1 and should be deleted upon completion of self-hosting.
     color: Color = .auto,
     reference_trace: ?u32 = null,
+    error_tracing: ?bool = null,
     test_filter: ?[]const u8 = null,
     test_name_prefix: ?[]const u8 = null,
     test_runner_path: ?[]const u8 = null,
@@ -1522,8 +1516,8 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
         cache.hash.add(link_libunwind);
         cache.hash.add(options.output_mode);
         cache.hash.add(options.machine_code_model);
-        cache.hash.addOptionalEmitLoc(options.emit_bin);
-        cache.hash.addOptionalEmitLoc(options.emit_implib);
+        cache_helpers.addOptionalEmitLoc(&cache.hash, options.emit_bin);
+        cache_helpers.addOptionalEmitLoc(&cache.hash, options.emit_implib);
         cache.hash.addBytes(options.root_name);
         if (options.target.os.tag == .wasi) cache.hash.add(wasi_exec_model);
         // TODO audit this and make sure everything is in it
@@ -1621,26 +1615,46 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
             const root_pkg = if (options.is_test) root_pkg: {
                 // TODO: we currently have two packages named 'root' here, which is weird. This
                 // should be changed as part of the resolution of #12201
-                const test_pkg = if (options.test_runner_path) |test_runner|
-                    try Package.create(gpa, "root", null, test_runner)
-                else
-                    try Package.createWithDir(
-                        gpa,
-                        "root",
-                        options.zig_lib_directory,
-                        null,
-                        "test_runner.zig",
-                    );
+                const test_pkg = if (options.test_runner_path) |test_runner| test_pkg: {
+                    const test_dir = std.fs.path.dirname(test_runner);
+                    const basename = std.fs.path.basename(test_runner);
+                    const pkg = try Package.create(gpa, "root", test_dir, basename);
+
+                    // copy package table from main_pkg to root_pkg
+                    pkg.table = try main_pkg.table.clone(gpa);
+                    break :test_pkg pkg;
+                } else try Package.createWithDir(
+                    gpa,
+                    "root",
+                    options.zig_lib_directory,
+                    null,
+                    "test_runner.zig",
+                );
                 errdefer test_pkg.destroy(gpa);
 
                 break :root_pkg test_pkg;
             } else main_pkg;
             errdefer if (options.is_test) root_pkg.destroy(gpa);
 
+            const compiler_rt_pkg = if (include_compiler_rt and options.output_mode == .Obj) compiler_rt_pkg: {
+                break :compiler_rt_pkg try Package.createWithDir(
+                    gpa,
+                    "compiler_rt",
+                    options.zig_lib_directory,
+                    null,
+                    "compiler_rt.zig",
+                );
+            } else null;
+            errdefer if (compiler_rt_pkg) |p| p.destroy(gpa);
+
             try main_pkg.addAndAdopt(gpa, builtin_pkg);
             try main_pkg.add(gpa, root_pkg);
             try main_pkg.addAndAdopt(gpa, std_pkg);
 
+            if (compiler_rt_pkg) |p| {
+                try main_pkg.addAndAdopt(gpa, p);
+            }
+
             const main_pkg_is_std = m: {
                 const std_path = try std.fs.path.resolve(arena, &[_][]const u8{
                     std_pkg.root_src_directory.path orelse ".",
@@ -1710,8 +1724,9 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
 
         const error_return_tracing = !strip and switch (options.optimize_mode) {
             .Debug, .ReleaseSafe => (!options.target.isWasm() or options.target.os.tag == .emscripten) and
-                !options.target.cpu.arch.isBpf(),
-            .ReleaseFast, .ReleaseSmall => false,
+                !options.target.cpu.arch.isBpf() and (options.error_tracing orelse true),
+            .ReleaseFast => options.error_tracing orelse false,
+            .ReleaseSmall => false,
         };
 
         // For resource management purposes.
@@ -1839,6 +1854,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
             .bind_global_refs_locally = options.linker_bind_global_refs_locally orelse false,
             .compress_debug_sections = options.linker_compress_debug_sections orelse .none,
             .module_definition_file = options.linker_module_definition_file,
+            .sort_section = options.linker_sort_section,
             .import_memory = options.linker_import_memory orelse false,
             .import_symbols = options.linker_import_symbols,
             .import_table = options.linker_import_table,
@@ -2356,6 +2372,10 @@ pub fn update(comp: *Compilation) !void {
             _ = try module.importPkg(module.main_pkg);
         }
 
+        if (module.main_pkg.table.get("compiler_rt")) |compiler_rt_pkg| {
+            _ = try module.importPkg(compiler_rt_pkg);
+        }
+
         // Put a work item in for every known source file to detect if
         // it changed, and, if so, re-compute ZIR and then queue the job
         // to update it.
@@ -2380,6 +2400,10 @@ pub fn update(comp: *Compilation) !void {
         if (comp.bin_file.options.is_test) {
             try comp.work_queue.writeItem(.{ .analyze_pkg = module.main_pkg });
         }
+
+        if (module.main_pkg.table.get("compiler_rt")) |compiler_rt_pkg| {
+            try comp.work_queue.writeItem(.{ .analyze_pkg = compiler_rt_pkg });
+        }
     }
 
     // If the terminal is dumb, we dont want to show the user all the output.
@@ -2631,11 +2655,11 @@ fn addNonIncrementalStuffToCacheManifest(comp: *Compilation, man: *Cache.Manifes
         man.hash.addListOfBytes(key.src.extra_flags);
     }
 
-    man.hash.addOptionalEmitLoc(comp.emit_asm);
-    man.hash.addOptionalEmitLoc(comp.emit_llvm_ir);
-    man.hash.addOptionalEmitLoc(comp.emit_llvm_bc);
-    man.hash.addOptionalEmitLoc(comp.emit_analysis);
-    man.hash.addOptionalEmitLoc(comp.emit_docs);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_asm);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_llvm_ir);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_llvm_bc);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_analysis);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_docs);
 
     man.hash.addListOfBytes(comp.clang_argv);
 
@@ -2662,6 +2686,7 @@ fn addNonIncrementalStuffToCacheManifest(comp: *Compilation, man: *Cache.Manifes
     man.hash.add(comp.bin_file.options.hash_style);
     man.hash.add(comp.bin_file.options.compress_debug_sections);
     man.hash.add(comp.bin_file.options.include_compiler_rt);
+    man.hash.addOptional(comp.bin_file.options.sort_section);
     if (comp.bin_file.options.link_libc) {
         man.hash.add(comp.bin_file.options.libc_installation != null);
         if (comp.bin_file.options.libc_installation) |libc_installation| {
@@ -3954,11 +3979,11 @@ fn updateCObject(comp: *Compilation, c_object: *CObject, c_obj_prog_node: *std.P
     defer man.deinit();
 
     man.hash.add(comp.clang_preprocessor_mode);
-    man.hash.addOptionalEmitLoc(comp.emit_asm);
-    man.hash.addOptionalEmitLoc(comp.emit_llvm_ir);
-    man.hash.addOptionalEmitLoc(comp.emit_llvm_bc);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_asm);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_llvm_ir);
+    cache_helpers.addOptionalEmitLoc(&man.hash, comp.emit_llvm_bc);
 
-    try man.hashCSource(c_object.src);
+    try cache_helpers.hashCSource(&man, c_object.src);
 
     var arena_allocator = std.heap.ArenaAllocator.init(comp.gpa);
     defer arena_allocator.deinit();
diff --git a/src/DepTokenizer.zig b/src/DepTokenizer.zig
deleted file mode 100644
index 8f9f2f81cd..0000000000
--- a/src/DepTokenizer.zig
+++ /dev/null
@@ -1,1069 +0,0 @@
-const Tokenizer = @This();
-
-index: usize = 0,
-bytes: []const u8,
-state: State = .lhs,
-
-const std = @import("std");
-const testing = std.testing;
-const assert = std.debug.assert;
-
-pub fn next(self: *Tokenizer) ?Token {
-    var start = self.index;
-    var must_resolve = false;
-    while (self.index < self.bytes.len) {
-        const char = self.bytes[self.index];
-        switch (self.state) {
-            .lhs => switch (char) {
-                '\t', '\n', '\r', ' ' => {
-                    // silently ignore whitespace
-                    self.index += 1;
-                },
-                else => {
-                    start = self.index;
-                    self.state = .target;
-                },
-            },
-            .target => switch (char) {
-                '\t', '\n', '\r', ' ' => {
-                    return errorIllegalChar(.invalid_target, self.index, char);
-                },
-                '$' => {
-                    self.state = .target_dollar_sign;
-                    self.index += 1;
-                },
-                '\\' => {
-                    self.state = .target_reverse_solidus;
-                    self.index += 1;
-                },
-                ':' => {
-                    self.state = .target_colon;
-                    self.index += 1;
-                },
-                else => {
-                    self.index += 1;
-                },
-            },
-            .target_reverse_solidus => switch (char) {
-                '\t', '\n', '\r' => {
-                    return errorIllegalChar(.bad_target_escape, self.index, char);
-                },
-                ' ', '#', '\\' => {
-                    must_resolve = true;
-                    self.state = .target;
-                    self.index += 1;
-                },
-                '$' => {
-                    self.state = .target_dollar_sign;
-                    self.index += 1;
-                },
-                else => {
-                    self.state = .target;
-                    self.index += 1;
-                },
-            },
-            .target_dollar_sign => switch (char) {
-                '$' => {
-                    must_resolve = true;
-                    self.state = .target;
-                    self.index += 1;
-                },
-                else => {
-                    return errorIllegalChar(.expected_dollar_sign, self.index, char);
-                },
-            },
-            .target_colon => switch (char) {
-                '\n', '\r' => {
-                    const bytes = self.bytes[start .. self.index - 1];
-                    if (bytes.len != 0) {
-                        self.state = .lhs;
-                        return finishTarget(must_resolve, bytes);
-                    }
-                    // silently ignore null target
-                    self.state = .lhs;
-                },
-                '/', '\\' => {
-                    self.state = .target_colon_reverse_solidus;
-                    self.index += 1;
-                },
-                else => {
-                    const bytes = self.bytes[start .. self.index - 1];
-                    if (bytes.len != 0) {
-                        self.state = .rhs;
-                        return finishTarget(must_resolve, bytes);
-                    }
-                    // silently ignore null target
-                    self.state = .lhs;
-                },
-            },
-            .target_colon_reverse_solidus => switch (char) {
-                '\n', '\r' => {
-                    const bytes = self.bytes[start .. self.index - 2];
-                    if (bytes.len != 0) {
-                        self.state = .lhs;
-                        return finishTarget(must_resolve, bytes);
-                    }
-                    // silently ignore null target
-                    self.state = .lhs;
-                },
-                else => {
-                    self.state = .target;
-                },
-            },
-            .rhs => switch (char) {
-                '\t', ' ' => {
-                    // silently ignore horizontal whitespace
-                    self.index += 1;
-                },
-                '\n', '\r' => {
-                    self.state = .lhs;
-                },
-                '\\' => {
-                    self.state = .rhs_continuation;
-                    self.index += 1;
-                },
-                '"' => {
-                    self.state = .prereq_quote;
-                    self.index += 1;
-                    start = self.index;
-                },
-                else => {
-                    start = self.index;
-                    self.state = .prereq;
-                },
-            },
-            .rhs_continuation => switch (char) {
-                '\n' => {
-                    self.state = .rhs;
-                    self.index += 1;
-                },
-                '\r' => {
-                    self.state = .rhs_continuation_linefeed;
-                    self.index += 1;
-                },
-                else => {
-                    return errorIllegalChar(.continuation_eol, self.index, char);
-                },
-            },
-            .rhs_continuation_linefeed => switch (char) {
-                '\n' => {
-                    self.state = .rhs;
-                    self.index += 1;
-                },
-                else => {
-                    return errorIllegalChar(.continuation_eol, self.index, char);
-                },
-            },
-            .prereq_quote => switch (char) {
-                '"' => {
-                    self.index += 1;
-                    self.state = .rhs;
-                    return Token{ .prereq = self.bytes[start .. self.index - 1] };
-                },
-                else => {
-                    self.index += 1;
-                },
-            },
-            .prereq => switch (char) {
-                '\t', ' ' => {
-                    self.state = .rhs;
-                    return Token{ .prereq = self.bytes[start..self.index] };
-                },
-                '\n', '\r' => {
-                    self.state = .lhs;
-                    return Token{ .prereq = self.bytes[start..self.index] };
-                },
-                '\\' => {
-                    self.state = .prereq_continuation;
-                    self.index += 1;
-                },
-                else => {
-                    self.index += 1;
-                },
-            },
-            .prereq_continuation => switch (char) {
-                '\n' => {
-                    self.index += 1;
-                    self.state = .rhs;
-                    return Token{ .prereq = self.bytes[start .. self.index - 2] };
-                },
-                '\r' => {
-                    self.state = .prereq_continuation_linefeed;
-                    self.index += 1;
-                },
-                else => {
-                    // not continuation
-                    self.state = .prereq;
-                    self.index += 1;
-                },
-            },
-            .prereq_continuation_linefeed => switch (char) {
-                '\n' => {
-                    self.index += 1;
-                    self.state = .rhs;
-                    return Token{ .prereq = self.bytes[start .. self.index - 1] };
-                },
-                else => {
-                    return errorIllegalChar(.continuation_eol, self.index, char);
-                },
-            },
-        }
-    } else {
-        switch (self.state) {
-            .lhs,
-            .rhs,
-            .rhs_continuation,
-            .rhs_continuation_linefeed,
-            => return null,
-            .target => {
-                return errorPosition(.incomplete_target, start, self.bytes[start..]);
-            },
-            .target_reverse_solidus,
-            .target_dollar_sign,
-            => {
-                const idx = self.index - 1;
-                return errorIllegalChar(.incomplete_escape, idx, self.bytes[idx]);
-            },
-            .target_colon => {
-                const bytes = self.bytes[start .. self.index - 1];
-                if (bytes.len != 0) {
-                    self.index += 1;
-                    self.state = .rhs;
-                    return finishTarget(must_resolve, bytes);
-                }
-                // silently ignore null target
-                self.state = .lhs;
-                return null;
-            },
-            .target_colon_reverse_solidus => {
-                const bytes = self.bytes[start .. self.index - 2];
-                if (bytes.len != 0) {
-                    self.index += 1;
-                    self.state = .rhs;
-                    return finishTarget(must_resolve, bytes);
-                }
-                // silently ignore null target
-                self.state = .lhs;
-                return null;
-            },
-            .prereq_quote => {
-                return errorPosition(.incomplete_quoted_prerequisite, start, self.bytes[start..]);
-            },
-            .prereq => {
-                self.state = .lhs;
-                return Token{ .prereq = self.bytes[start..] };
-            },
-            .prereq_continuation => {
-                self.state = .lhs;
-                return Token{ .prereq = self.bytes[start .. self.index - 1] };
-            },
-            .prereq_continuation_linefeed => {
-                self.state = .lhs;
-                return Token{ .prereq = self.bytes[start .. self.index - 2] };
-            },
-        }
-    }
-    unreachable;
-}
-
-fn errorPosition(comptime id: std.meta.Tag(Token), index: usize, bytes: []const u8) Token {
-    return @unionInit(Token, @tagName(id), .{ .index = index, .bytes = bytes });
-}
-
-fn errorIllegalChar(comptime id: std.meta.Tag(Token), index: usize, char: u8) Token {
-    return @unionInit(Token, @tagName(id), .{ .index = index, .char = char });
-}
-
-fn finishTarget(must_resolve: bool, bytes: []const u8) Token {
-    return if (must_resolve) .{ .target_must_resolve = bytes } else .{ .target = bytes };
-}
-
-const State = enum {
-    lhs,
-    target,
-    target_reverse_solidus,
-    target_dollar_sign,
-    target_colon,
-    target_colon_reverse_solidus,
-    rhs,
-    rhs_continuation,
-    rhs_continuation_linefeed,
-    prereq_quote,
-    prereq,
-    prereq_continuation,
-    prereq_continuation_linefeed,
-};
-
-pub const Token = union(enum) {
-    target: []const u8,
-    target_must_resolve: []const u8,
-    prereq: []const u8,
-
-    incomplete_quoted_prerequisite: IndexAndBytes,
-    incomplete_target: IndexAndBytes,
-
-    invalid_target: IndexAndChar,
-    bad_target_escape: IndexAndChar,
-    expected_dollar_sign: IndexAndChar,
-    continuation_eol: IndexAndChar,
-    incomplete_escape: IndexAndChar,
-
-    pub const IndexAndChar = struct {
-        index: usize,
-        char: u8,
-    };
-
-    pub const IndexAndBytes = struct {
-        index: usize,
-        bytes: []const u8,
-    };
-
-    /// Resolve escapes in target. Only valid with .target_must_resolve.
-    pub fn resolve(self: Token, writer: anytype) @TypeOf(writer).Error!void {
-        const bytes = self.target_must_resolve; // resolve called on incorrect token
-
-        var state: enum { start, escape, dollar } = .start;
-        for (bytes) |c| {
-            switch (state) {
-                .start => {
-                    switch (c) {
-                        '\\' => state = .escape,
-                        '$' => state = .dollar,
-                        else => try writer.writeByte(c),
-                    }
-                },
-                .escape => {
-                    switch (c) {
-                        ' ', '#', '\\' => {},
-                        '$' => {
-                            try writer.writeByte('\\');
-                            state = .dollar;
-                            continue;
-                        },
-                        else => try writer.writeByte('\\'),
-                    }
-                    try writer.writeByte(c);
-                    state = .start;
-                },
-                .dollar => {
-                    try writer.writeByte('$');
-                    switch (c) {
-                        '$' => {},
-                        else => try writer.writeByte(c),
-                    }
-                    state = .start;
-                },
-            }
-        }
-    }
-
-    pub fn printError(self: Token, writer: anytype) @TypeOf(writer).Error!void {
-        switch (self) {
-            .target, .target_must_resolve, .prereq => unreachable, // not an error
-            .incomplete_quoted_prerequisite,
-            .incomplete_target,
-            => |index_and_bytes| {
-                try writer.print("{s} '", .{self.errStr()});
-                if (self == .incomplete_target) {
-                    const tmp = Token{ .target_must_resolve = index_and_bytes.bytes };
-                    try tmp.resolve(writer);
-                } else {
-                    try printCharValues(writer, index_and_bytes.bytes);
-                }
-                try writer.print("' at position {d}", .{index_and_bytes.index});
-            },
-            .invalid_target,
-            .bad_target_escape,
-            .expected_dollar_sign,
-            .continuation_eol,
-            .incomplete_escape,
-            => |index_and_char| {
-                try writer.writeAll("illegal char ");
-                try printUnderstandableChar(writer, index_and_char.char);
-                try writer.print(" at position {d}: {s}", .{ index_and_char.index, self.errStr() });
-            },
-        }
-    }
-
-    fn errStr(self: Token) []const u8 {
-        return switch (self) {
-            .target, .target_must_resolve, .prereq => unreachable, // not an error
-            .incomplete_quoted_prerequisite => "incomplete quoted prerequisite",
-            .incomplete_target => "incomplete target",
-            .invalid_target => "invalid target",
-            .bad_target_escape => "bad target escape",
-            .expected_dollar_sign => "expecting '$'",
-            .continuation_eol => "continuation expecting end-of-line",
-            .incomplete_escape => "incomplete escape",
-        };
-    }
-};
-
-test "empty file" {
-    try depTokenizer("", "");
-}
-
-test "empty whitespace" {
-    try depTokenizer("\n", "");
-    try depTokenizer("\r", "");
-    try depTokenizer("\r\n", "");
-    try depTokenizer(" ", "");
-}
-
-test "empty colon" {
-    try depTokenizer(":", "");
-    try depTokenizer("\n:", "");
-    try depTokenizer("\r:", "");
-    try depTokenizer("\r\n:", "");
-    try depTokenizer(" :", "");
-}
-
-test "empty target" {
-    try depTokenizer("foo.o:", "target = {foo.o}");
-    try depTokenizer(
-        \\foo.o:
-        \\bar.o:
-        \\abcd.o:
-    ,
-        \\target = {foo.o}
-        \\target = {bar.o}
-        \\target = {abcd.o}
-    );
-}
-
-test "whitespace empty target" {
-    try depTokenizer("\nfoo.o:", "target = {foo.o}");
-    try depTokenizer("\rfoo.o:", "target = {foo.o}");
-    try depTokenizer("\r\nfoo.o:", "target = {foo.o}");
-    try depTokenizer(" foo.o:", "target = {foo.o}");
-}
-
-test "escape empty target" {
-    try depTokenizer("\\ foo.o:", "target = { foo.o}");
-    try depTokenizer("\\#foo.o:", "target = {#foo.o}");
-    try depTokenizer("\\\\foo.o:", "target = {\\foo.o}");
-    try depTokenizer("$$foo.o:", "target = {$foo.o}");
-}
-
-test "empty target linefeeds" {
-    try depTokenizer("\n", "");
-    try depTokenizer("\r\n", "");
-
-    const expect = "target = {foo.o}";
-    try depTokenizer(
-        \\foo.o:
-    , expect);
-    try depTokenizer(
-        \\foo.o:
-        \\
-    , expect);
-    try depTokenizer(
-        \\foo.o:
-    , expect);
-    try depTokenizer(
-        \\foo.o:
-        \\
-    , expect);
-}
-
-test "empty target linefeeds + continuations" {
-    const expect = "target = {foo.o}";
-    try depTokenizer(
-        \\foo.o:\
-    , expect);
-    try depTokenizer(
-        \\foo.o:\
-        \\
-    , expect);
-    try depTokenizer(
-        \\foo.o:\
-    , expect);
-    try depTokenizer(
-        \\foo.o:\
-        \\
-    , expect);
-}
-
-test "empty target linefeeds + hspace + continuations" {
-    const expect = "target = {foo.o}";
-    try depTokenizer(
-        \\foo.o: \
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\
-    , expect);
-}
-
-test "prereq" {
-    const expect =
-        \\target = {foo.o}
-        \\prereq = {foo.c}
-    ;
-    try depTokenizer("foo.o: foo.c", expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\foo.c
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\ foo.c
-    , expect);
-    try depTokenizer(
-        \\foo.o:    \
-        \\    foo.c
-    , expect);
-}
-
-test "prereq continuation" {
-    const expect =
-        \\target = {foo.o}
-        \\prereq = {foo.h}
-        \\prereq = {bar.h}
-    ;
-    try depTokenizer(
-        \\foo.o: foo.h\
-        \\bar.h
-    , expect);
-    try depTokenizer(
-        \\foo.o: foo.h\
-        \\bar.h
-    , expect);
-}
-
-test "multiple prereqs" {
-    const expect =
-        \\target = {foo.o}
-        \\prereq = {foo.c}
-        \\prereq = {foo.h}
-        \\prereq = {bar.h}
-    ;
-    try depTokenizer("foo.o: foo.c foo.h bar.h", expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\foo.c foo.h bar.h
-    , expect);
-    try depTokenizer(
-        \\foo.o: foo.c foo.h bar.h\
-    , expect);
-    try depTokenizer(
-        \\foo.o: foo.c foo.h bar.h\
-        \\
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\foo.c       \
-        \\     foo.h\
-        \\bar.h
-        \\
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\foo.c       \
-        \\     foo.h\
-        \\bar.h\
-        \\
-    , expect);
-    try depTokenizer(
-        \\foo.o: \
-        \\foo.c       \
-        \\     foo.h\
-        \\bar.h\
-    , expect);
-}
-
-test "multiple targets and prereqs" {
-    try depTokenizer(
-        \\foo.o: foo.c
-        \\bar.o: bar.c a.h b.h c.h
-        \\abc.o: abc.c \
-        \\  one.h two.h \
-        \\  three.h four.h
-    ,
-        \\target = {foo.o}
-        \\prereq = {foo.c}
-        \\target = {bar.o}
-        \\prereq = {bar.c}
-        \\prereq = {a.h}
-        \\prereq = {b.h}
-        \\prereq = {c.h}
-        \\target = {abc.o}
-        \\prereq = {abc.c}
-        \\prereq = {one.h}
-        \\prereq = {two.h}
-        \\prereq = {three.h}
-        \\prereq = {four.h}
-    );
-    try depTokenizer(
-        \\ascii.o: ascii.c
-        \\base64.o: base64.c stdio.h
-        \\elf.o: elf.c a.h b.h c.h
-        \\macho.o: \
-        \\  macho.c\
-        \\  a.h b.h c.h
-    ,
-        \\target = {ascii.o}
-        \\prereq = {ascii.c}
-        \\target = {base64.o}
-        \\prereq = {base64.c}
-        \\prereq = {stdio.h}
-        \\target = {elf.o}
-        \\prereq = {elf.c}
-        \\prereq = {a.h}
-        \\prereq = {b.h}
-        \\prereq = {c.h}
-        \\target = {macho.o}
-        \\prereq = {macho.c}
-        \\prereq = {a.h}
-        \\prereq = {b.h}
-        \\prereq = {c.h}
-    );
-    try depTokenizer(
-        \\a$$scii.o: ascii.c
-        \\\\base64.o: "\base64.c" "s t#dio.h"
-        \\e\\lf.o: "e\lf.c" "a.h$$" "$$b.h c.h$$"
-        \\macho.o: \
-        \\  "macho!.c" \
-        \\  a.h b.h c.h
-    ,
-        \\target = {a$scii.o}
-        \\prereq = {ascii.c}
-        \\target = {\base64.o}
-        \\prereq = {\base64.c}
-        \\prereq = {s t#dio.h}
-        \\target = {e\lf.o}
-        \\prereq = {e\lf.c}
-        \\prereq = {a.h$$}
-        \\prereq = {$$b.h c.h$$}
-        \\target = {macho.o}
-        \\prereq = {macho!.c}
-        \\prereq = {a.h}
-        \\prereq = {b.h}
-        \\prereq = {c.h}
-    );
-}
-
-test "windows quoted prereqs" {
-    try depTokenizer(
-        \\c:\foo.o: "C:\Program Files (x86)\Microsoft Visual Studio\foo.c"
-        \\c:\foo2.o: "C:\Program Files (x86)\Microsoft Visual Studio\foo2.c" \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\foo1.h" \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\foo2.h"
-    ,
-        \\target = {c:\foo.o}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\foo.c}
-        \\target = {c:\foo2.o}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\foo2.c}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\foo1.h}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\foo2.h}
-    );
-}
-
-test "windows mixed prereqs" {
-    try depTokenizer(
-        \\cimport.o: \
-        \\  C:\msys64\home\anon\project\zig\master\zig-cache\o\qhvhbUo7GU5iKyQ5mpA8TcQpncCYaQu0wwvr3ybiSTj_Dtqi1Nmcb70kfODJ2Qlg\cimport.h \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\stdio.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt.h" \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\vcruntime.h" \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\sal.h" \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\concurrencysal.h" \
-        \\  C:\msys64\opt\zig\lib\zig\include\vadefs.h \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\vadefs.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_wstdio.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_stdio_config.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\string.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_memory.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_memcpy_s.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\errno.h" \
-        \\  "C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\vcruntime_string.h" \
-        \\  "C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_wstring.h"
-    ,
-        \\target = {cimport.o}
-        \\prereq = {C:\msys64\home\anon\project\zig\master\zig-cache\o\qhvhbUo7GU5iKyQ5mpA8TcQpncCYaQu0wwvr3ybiSTj_Dtqi1Nmcb70kfODJ2Qlg\cimport.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\stdio.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt.h}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\vcruntime.h}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\sal.h}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\concurrencysal.h}
-        \\prereq = {C:\msys64\opt\zig\lib\zig\include\vadefs.h}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\vadefs.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_wstdio.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_stdio_config.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\string.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_memory.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_memcpy_s.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\errno.h}
-        \\prereq = {C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.21.27702\lib\x64\\..\..\include\vcruntime_string.h}
-        \\prereq = {C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17763.0\ucrt\corecrt_wstring.h}
-    );
-}
-
-test "windows funky targets" {
-    try depTokenizer(
-        \\C:\Users\anon\foo.o:
-        \\C:\Users\anon\foo\ .o:
-        \\C:\Users\anon\foo\#.o:
-        \\C:\Users\anon\foo$$.o:
-        \\C:\Users\anon\\\ foo.o:
-        \\C:\Users\anon\\#foo.o:
-        \\C:\Users\anon\$$foo.o:
-        \\C:\Users\anon\\\ \ \ \ \ foo.o:
-    ,
-        \\target = {C:\Users\anon\foo.o}
-        \\target = {C:\Users\anon\foo .o}
-        \\target = {C:\Users\anon\foo#.o}
-        \\target = {C:\Users\anon\foo$.o}
-        \\target = {C:\Users\anon\ foo.o}
-        \\target = {C:\Users\anon\#foo.o}
-        \\target = {C:\Users\anon\$foo.o}
-        \\target = {C:\Users\anon\     foo.o}
-    );
-}
-
-test "windows drive and forward slashes" {
-    try depTokenizer(
-        \\C:/msys64/what/zig-cache\tmp\48ac4d78dd531abd-cxa_thread_atexit.obj: \
-        \\  C:/msys64/opt/zig3/lib/zig/libc/mingw/crt/cxa_thread_atexit.c
-    ,
-        \\target = {C:/msys64/what/zig-cache\tmp\48ac4d78dd531abd-cxa_thread_atexit.obj}
-        \\prereq = {C:/msys64/opt/zig3/lib/zig/libc/mingw/crt/cxa_thread_atexit.c}
-    );
-}
-
-test "error incomplete escape - reverse_solidus" {
-    try depTokenizer("\\",
-        \\ERROR: illegal char '\' at position 0: incomplete escape
-    );
-    try depTokenizer("\t\\",
-        \\ERROR: illegal char '\' at position 1: incomplete escape
-    );
-    try depTokenizer("\n\\",
-        \\ERROR: illegal char '\' at position 1: incomplete escape
-    );
-    try depTokenizer("\r\\",
-        \\ERROR: illegal char '\' at position 1: incomplete escape
-    );
-    try depTokenizer("\r\n\\",
-        \\ERROR: illegal char '\' at position 2: incomplete escape
-    );
-    try depTokenizer(" \\",
-        \\ERROR: illegal char '\' at position 1: incomplete escape
-    );
-}
-
-test "error incomplete escape - dollar_sign" {
-    try depTokenizer("$",
-        \\ERROR: illegal char '$' at position 0: incomplete escape
-    );
-    try depTokenizer("\t$",
-        \\ERROR: illegal char '$' at position 1: incomplete escape
-    );
-    try depTokenizer("\n$",
-        \\ERROR: illegal char '$' at position 1: incomplete escape
-    );
-    try depTokenizer("\r$",
-        \\ERROR: illegal char '$' at position 1: incomplete escape
-    );
-    try depTokenizer("\r\n$",
-        \\ERROR: illegal char '$' at position 2: incomplete escape
-    );
-    try depTokenizer(" $",
-        \\ERROR: illegal char '$' at position 1: incomplete escape
-    );
-}
-
-test "error incomplete target" {
-    try depTokenizer("foo.o",
-        \\ERROR: incomplete target 'foo.o' at position 0
-    );
-    try depTokenizer("\tfoo.o",
-        \\ERROR: incomplete target 'foo.o' at position 1
-    );
-    try depTokenizer("\nfoo.o",
-        \\ERROR: incomplete target 'foo.o' at position 1
-    );
-    try depTokenizer("\rfoo.o",
-        \\ERROR: incomplete target 'foo.o' at position 1
-    );
-    try depTokenizer("\r\nfoo.o",
-        \\ERROR: incomplete target 'foo.o' at position 2
-    );
-    try depTokenizer(" foo.o",
-        \\ERROR: incomplete target 'foo.o' at position 1
-    );
-
-    try depTokenizer("\\ foo.o",
-        \\ERROR: incomplete target ' foo.o' at position 0
-    );
-    try depTokenizer("\\#foo.o",
-        \\ERROR: incomplete target '#foo.o' at position 0
-    );
-    try depTokenizer("\\\\foo.o",
-        \\ERROR: incomplete target '\foo.o' at position 0
-    );
-    try depTokenizer("$$foo.o",
-        \\ERROR: incomplete target '$foo.o' at position 0
-    );
-}
-
-test "error illegal char at position - bad target escape" {
-    try depTokenizer("\\\t",
-        \\ERROR: illegal char \x09 at position 1: bad target escape
-    );
-    try depTokenizer("\\\n",
-        \\ERROR: illegal char \x0A at position 1: bad target escape
-    );
-    try depTokenizer("\\\r",
-        \\ERROR: illegal char \x0D at position 1: bad target escape
-    );
-    try depTokenizer("\\\r\n",
-        \\ERROR: illegal char \x0D at position 1: bad target escape
-    );
-}
-
-test "error illegal char at position - execting dollar_sign" {
-    try depTokenizer("$\t",
-        \\ERROR: illegal char \x09 at position 1: expecting '$'
-    );
-    try depTokenizer("$\n",
-        \\ERROR: illegal char \x0A at position 1: expecting '$'
-    );
-    try depTokenizer("$\r",
-        \\ERROR: illegal char \x0D at position 1: expecting '$'
-    );
-    try depTokenizer("$\r\n",
-        \\ERROR: illegal char \x0D at position 1: expecting '$'
-    );
-}
-
-test "error illegal char at position - invalid target" {
-    try depTokenizer("foo\t.o",
-        \\ERROR: illegal char \x09 at position 3: invalid target
-    );
-    try depTokenizer("foo\n.o",
-        \\ERROR: illegal char \x0A at position 3: invalid target
-    );
-    try depTokenizer("foo\r.o",
-        \\ERROR: illegal char \x0D at position 3: invalid target
-    );
-    try depTokenizer("foo\r\n.o",
-        \\ERROR: illegal char \x0D at position 3: invalid target
-    );
-}
-
-test "error target - continuation expecting end-of-line" {
-    try depTokenizer("foo.o: \\\t",
-        \\target = {foo.o}
-        \\ERROR: illegal char \x09 at position 8: continuation expecting end-of-line
-    );
-    try depTokenizer("foo.o: \\ ",
-        \\target = {foo.o}
-        \\ERROR: illegal char ' ' at position 8: continuation expecting end-of-line
-    );
-    try depTokenizer("foo.o: \\x",
-        \\target = {foo.o}
-        \\ERROR: illegal char 'x' at position 8: continuation expecting end-of-line
-    );
-    try depTokenizer("foo.o: \\\x0dx",
-        \\target = {foo.o}
-        \\ERROR: illegal char 'x' at position 9: continuation expecting end-of-line
-    );
-}
-
-test "error prereq - continuation expecting end-of-line" {
-    try depTokenizer("foo.o: foo.h\\\x0dx",
-        \\target = {foo.o}
-        \\ERROR: illegal char 'x' at position 14: continuation expecting end-of-line
-    );
-}
-
-// - tokenize input, emit textual representation, and compare to expect
-fn depTokenizer(input: []const u8, expect: []const u8) !void {
-    var arena_allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
-    const arena = arena_allocator.allocator();
-    defer arena_allocator.deinit();
-
-    var it: Tokenizer = .{ .bytes = input };
-    var buffer = std.ArrayList(u8).init(arena);
-    var resolve_buf = std.ArrayList(u8).init(arena);
-    var i: usize = 0;
-    while (it.next()) |token| {
-        if (i != 0) try buffer.appendSlice("\n");
-        switch (token) {
-            .target, .prereq => |bytes| {
-                try buffer.appendSlice(@tagName(token));
-                try buffer.appendSlice(" = {");
-                for (bytes) |b| {
-                    try buffer.append(printable_char_tab[b]);
-                }
-                try buffer.appendSlice("}");
-            },
-            .target_must_resolve => {
-                try buffer.appendSlice("target = {");
-                try token.resolve(resolve_buf.writer());
-                for (resolve_buf.items) |b| {
-                    try buffer.append(printable_char_tab[b]);
-                }
-                resolve_buf.items.len = 0;
-                try buffer.appendSlice("}");
-            },
-            else => {
-                try buffer.appendSlice("ERROR: ");
-                try token.printError(buffer.writer());
-                break;
-            },
-        }
-        i += 1;
-    }
-
-    if (std.mem.eql(u8, expect, buffer.items)) {
-        try testing.expect(true);
-        return;
-    }
-
-    const out = std.io.getStdErr().writer();
-
-    try out.writeAll("\n");
-    try printSection(out, "<<<< input", input);
-    try printSection(out, "==== expect", expect);
-    try printSection(out, ">>>> got", buffer.items);
-    try printRuler(out);
-
-    try testing.expect(false);
-}
-
-fn printSection(out: anytype, label: []const u8, bytes: []const u8) !void {
-    try printLabel(out, label, bytes);
-    try hexDump(out, bytes);
-    try printRuler(out);
-    try out.writeAll(bytes);
-    try out.writeAll("\n");
-}
-
-fn printLabel(out: anytype, label: []const u8, bytes: []const u8) !void {
-    var buf: [80]u8 = undefined;
-    var text = try std.fmt.bufPrint(buf[0..], "{s} {d} bytes ", .{ label, bytes.len });
-    try out.writeAll(text);
-    var i: usize = text.len;
-    const end = 79;
-    while (i < end) : (i += 1) {
-        try out.writeAll(&[_]u8{label[0]});
-    }
-    try out.writeAll("\n");
-}
-
-fn printRuler(out: anytype) !void {
-    var i: usize = 0;
-    const end = 79;
-    while (i < end) : (i += 1) {
-        try out.writeAll("-");
-    }
-    try out.writeAll("\n");
-}
-
-fn hexDump(out: anytype, bytes: []const u8) !void {
-    const n16 = bytes.len >> 4;
-    var line: usize = 0;
-    var offset: usize = 0;
-    while (line < n16) : (line += 1) {
-        try hexDump16(out, offset, bytes[offset .. offset + 16]);
-        offset += 16;
-    }
-
-    const n = bytes.len & 0x0f;
-    if (n > 0) {
-        try printDecValue(out, offset, 8);
-        try out.writeAll(":");
-        try out.writeAll(" ");
-        var end1 = std.math.min(offset + n, offset + 8);
-        for (bytes[offset..end1]) |b| {
-            try out.writeAll(" ");
-            try printHexValue(out, b, 2);
-        }
-        var end2 = offset + n;
-        if (end2 > end1) {
-            try out.writeAll(" ");
-            for (bytes[end1..end2]) |b| {
-                try out.writeAll(" ");
-                try printHexValue(out, b, 2);
-            }
-        }
-        const short = 16 - n;
-        var i: usize = 0;
-        while (i < short) : (i += 1) {
-            try out.writeAll("   ");
-        }
-        if (end2 > end1) {
-            try out.writeAll("  |");
-        } else {
-            try out.writeAll("   |");
-        }
-        try printCharValues(out, bytes[offset..end2]);
-        try out.writeAll("|\n");
-        offset += n;
-    }
-
-    try printDecValue(out, offset, 8);
-    try out.writeAll(":");
-    try out.writeAll("\n");
-}
-
-fn hexDump16(out: anytype, offset: usize, bytes: []const u8) !void {
-    try printDecValue(out, offset, 8);
-    try out.writeAll(":");
-    try out.writeAll(" ");
-    for (bytes[0..8]) |b| {
-        try out.writeAll(" ");
-        try printHexValue(out, b, 2);
-    }
-    try out.writeAll(" ");
-    for (bytes[8..16]) |b| {
-        try out.writeAll(" ");
-        try printHexValue(out, b, 2);
-    }
-    try out.writeAll("  |");
-    try printCharValues(out, bytes);
-    try out.writeAll("|\n");
-}
-
-fn printDecValue(out: anytype, value: u64, width: u8) !void {
-    var buffer: [20]u8 = undefined;
-    const len = std.fmt.formatIntBuf(buffer[0..], value, 10, .lower, .{ .width = width, .fill = '0' });
-    try out.writeAll(buffer[0..len]);
-}
-
-fn printHexValue(out: anytype, value: u64, width: u8) !void {
-    var buffer: [16]u8 = undefined;
-    const len = std.fmt.formatIntBuf(buffer[0..], value, 16, .lower, .{ .width = width, .fill = '0' });
-    try out.writeAll(buffer[0..len]);
-}
-
-fn printCharValues(out: anytype, bytes: []const u8) !void {
-    for (bytes) |b| {
-        try out.writeAll(&[_]u8{printable_char_tab[b]});
-    }
-}
-
-fn printUnderstandableChar(out: anytype, char: u8) !void {
-    if (std.ascii.isPrint(char)) {
-        try out.print("'{c}'", .{char});
-    } else {
-        try out.print("\\x{X:0>2}", .{char});
-    }
-}
-
-// zig fmt: off
-const printable_char_tab: [256]u8 = (
-    "................................ !\"#$%&'()*+,-./0123456789:;<=>?" ++
-    "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~." ++
-    "................................................................" ++
-    "................................................................"
-).*;
diff --git a/src/Module.zig b/src/Module.zig
index 3243c36ee5..a129cb0cb6 100644
--- a/src/Module.zig
+++ b/src/Module.zig
@@ -16,7 +16,7 @@ const Ast = std.zig.Ast;
 
 const Module = @This();
 const Compilation = @import("Compilation.zig");
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 const Value = @import("value.zig").Value;
 const Type = @import("type.zig").Type;
 const TypedValue = @import("TypedValue.zig");
@@ -4865,14 +4865,31 @@ pub fn importFile(
     };
 }
 
-pub fn embedFile(mod: *Module, cur_file: *File, rel_file_path: []const u8) !*EmbedFile {
+pub fn embedFile(mod: *Module, cur_file: *File, import_string: []const u8) !*EmbedFile {
     const gpa = mod.gpa;
 
-    // The resolved path is used as the key in the table, to detect if
-    // a file refers to the same as another, despite different relative paths.
+    if (cur_file.pkg.table.get(import_string)) |pkg| {
+        const resolved_path = try std.fs.path.resolve(gpa, &[_][]const u8{
+            pkg.root_src_directory.path orelse ".", pkg.root_src_path,
+        });
+        var keep_resolved_path = false;
+        defer if (!keep_resolved_path) gpa.free(resolved_path);
+
+        const gop = try mod.embed_table.getOrPut(gpa, resolved_path);
+        errdefer assert(mod.embed_table.remove(resolved_path));
+        if (gop.found_existing) return gop.value_ptr.*;
+
+        const sub_file_path = try gpa.dupe(u8, pkg.root_src_path);
+        errdefer gpa.free(sub_file_path);
+
+        return newEmbedFile(mod, pkg, sub_file_path, resolved_path, &keep_resolved_path, gop);
+    }
+
+    // The resolved path is used as the key in the table, to detect if a file
+    // refers to the same as another, despite different relative paths.
     const cur_pkg_dir_path = cur_file.pkg.root_src_directory.path orelse ".";
     const resolved_path = try std.fs.path.resolve(gpa, &[_][]const u8{
-        cur_pkg_dir_path, cur_file.sub_file_path, "..", rel_file_path,
+        cur_pkg_dir_path, cur_file.sub_file_path, "..", import_string,
     });
     var keep_resolved_path = false;
     defer if (!keep_resolved_path) gpa.free(resolved_path);
@@ -4881,9 +4898,6 @@ pub fn embedFile(mod: *Module, cur_file: *File, rel_file_path: []const u8) !*Emb
     errdefer assert(mod.embed_table.remove(resolved_path));
     if (gop.found_existing) return gop.value_ptr.*;
 
-    const new_file = try gpa.create(EmbedFile);
-    errdefer gpa.destroy(new_file);
-
     const resolved_root_path = try std.fs.path.resolve(gpa, &[_][]const u8{cur_pkg_dir_path});
     defer gpa.free(resolved_root_path);
 
@@ -4902,7 +4916,23 @@ pub fn embedFile(mod: *Module, cur_file: *File, rel_file_path: []const u8) !*Emb
     };
     errdefer gpa.free(sub_file_path);
 
-    var file = try cur_file.pkg.root_src_directory.handle.openFile(sub_file_path, .{});
+    return newEmbedFile(mod, cur_file.pkg, sub_file_path, resolved_path, &keep_resolved_path, gop);
+}
+
+fn newEmbedFile(
+    mod: *Module,
+    pkg: *Package,
+    sub_file_path: []const u8,
+    resolved_path: []const u8,
+    keep_resolved_path: *bool,
+    gop: std.StringHashMapUnmanaged(*EmbedFile).GetOrPutResult,
+) !*EmbedFile {
+    const gpa = mod.gpa;
+
+    const new_file = try gpa.create(EmbedFile);
+    errdefer gpa.destroy(new_file);
+
+    var file = try pkg.root_src_directory.handle.openFile(sub_file_path, .{});
     defer file.close();
 
     const actual_stat = try file.stat();
@@ -4915,10 +4945,6 @@ pub fn embedFile(mod: *Module, cur_file: *File, rel_file_path: []const u8) !*Emb
     const bytes = try file.readToEndAllocOptions(gpa, std.math.maxInt(u32), size_usize, 1, 0);
     errdefer gpa.free(bytes);
 
-    log.debug("new embedFile. resolved_root_path={s}, resolved_path={s}, sub_file_path={s}, rel_file_path={s}", .{
-        resolved_root_path, resolved_path, sub_file_path, rel_file_path,
-    });
-
     if (mod.comp.whole_cache_manifest) |whole_cache_manifest| {
         const copied_resolved_path = try gpa.dupe(u8, resolved_path);
         errdefer gpa.free(copied_resolved_path);
@@ -4927,13 +4953,13 @@ pub fn embedFile(mod: *Module, cur_file: *File, rel_file_path: []const u8) !*Emb
         try whole_cache_manifest.addFilePostContents(copied_resolved_path, bytes, stat);
     }
 
-    keep_resolved_path = true; // It's now owned by embed_table.
+    keep_resolved_path.* = true; // It's now owned by embed_table.
     gop.value_ptr.* = new_file;
     new_file.* = .{
         .sub_file_path = sub_file_path,
         .bytes = bytes,
         .stat = stat,
-        .pkg = cur_file.pkg,
+        .pkg = pkg,
         .owner_decl = undefined, // Set by Sema immediately after this function returns.
     };
     return new_file;
diff --git a/src/Package.zig b/src/Package.zig
index 401eef2121..a3afe21009 100644
--- a/src/Package.zig
+++ b/src/Package.zig
@@ -13,7 +13,7 @@ const Compilation = @import("Compilation.zig");
 const Module = @import("Module.zig");
 const ThreadPool = @import("ThreadPool.zig");
 const WaitGroup = @import("WaitGroup.zig");
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 const build_options = @import("build_options");
 const Manifest = @import("Manifest.zig");
 
diff --git a/src/Sema.zig b/src/Sema.zig
index b7b3a55063..cf6350e35f 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -1015,7 +1015,6 @@ fn analyzeBodyInner(
             .float_cast                   => try sema.zirFloatCast(block, inst),
             .int_cast                     => try sema.zirIntCast(block, inst),
             .ptr_cast                     => try sema.zirPtrCast(block, inst),
-            .qual_cast                    => try sema.zirQualCast(block, inst),
             .truncate                     => try sema.zirTruncate(block, inst),
             .align_cast                   => try sema.zirAlignCast(block, inst),
             .has_decl                     => try sema.zirHasDecl(block, inst),
@@ -1147,6 +1146,8 @@ fn analyzeBodyInner(
                     .c_va_copy             => try sema.zirCVaCopy(           block, extended),
                     .c_va_end              => try sema.zirCVaEnd(            block, extended),
                     .c_va_start            => try sema.zirCVaStart(          block, extended),
+                    .const_cast,           => try sema.zirConstCast(         block, extended),
+                    .volatile_cast,        => try sema.zirVolatileCast(      block, extended),
                     // zig fmt: on
 
                     .fence => {
@@ -7669,17 +7670,21 @@ fn zirErrorUnionType(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileEr
             error_set.fmt(sema.mod),
         });
     }
-    if (payload.zigTypeTag() == .Opaque) {
-        return sema.fail(block, rhs_src, "error union with payload of opaque type '{}' not allowed", .{
-            payload.fmt(sema.mod),
+    try sema.validateErrorUnionPayloadType(block, payload, rhs_src);
+    const err_union_ty = try Type.errorUnion(sema.arena, error_set, payload, sema.mod);
+    return sema.addType(err_union_ty);
+}
+
+fn validateErrorUnionPayloadType(sema: *Sema, block: *Block, payload_ty: Type, payload_src: LazySrcLoc) !void {
+    if (payload_ty.zigTypeTag() == .Opaque) {
+        return sema.fail(block, payload_src, "error union with payload of opaque type '{}' not allowed", .{
+            payload_ty.fmt(sema.mod),
         });
-    } else if (payload.zigTypeTag() == .ErrorSet) {
-        return sema.fail(block, rhs_src, "error union with payload of error set type '{}' not allowed", .{
-            payload.fmt(sema.mod),
+    } else if (payload_ty.zigTypeTag() == .ErrorSet) {
+        return sema.fail(block, payload_src, "error union with payload of error set type '{}' not allowed", .{
+            payload_ty.fmt(sema.mod),
         });
     }
-    const err_union_ty = try Type.errorUnion(sema.arena, error_set, payload, sema.mod);
-    return sema.addType(err_union_ty);
 }
 
 fn zirErrorValue(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
@@ -8639,6 +8644,7 @@ fn funcCommon(
         const return_type = if (!inferred_error_set or ret_poison)
             bare_return_type
         else blk: {
+            try sema.validateErrorUnionPayloadType(block, bare_return_type, ret_ty_src);
             const node = try sema.gpa.create(Module.Fn.InferredErrorSetListNode);
             node.data = .{ .func = new_func };
             maybe_inferred_error_set_node = node;
@@ -8650,15 +8656,15 @@ fn funcCommon(
             });
         };
 
-        if (!bare_return_type.isValidReturnType()) {
-            const opaque_str = if (bare_return_type.zigTypeTag() == .Opaque) "opaque " else "";
+        if (!return_type.isValidReturnType()) {
+            const opaque_str = if (return_type.zigTypeTag() == .Opaque) "opaque " else "";
             const msg = msg: {
                 const msg = try sema.errMsg(block, ret_ty_src, "{s}return type '{}' not allowed", .{
-                    opaque_str, bare_return_type.fmt(sema.mod),
+                    opaque_str, return_type.fmt(sema.mod),
                 });
                 errdefer msg.destroy(sema.gpa);
 
-                try sema.addDeclaredHereNote(msg, bare_return_type);
+                try sema.addDeclaredHereNote(msg, return_type);
                 break :msg msg;
             };
             return sema.failWithOwnedErrorMsg(msg);
@@ -19540,7 +19546,7 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
             const msg = try sema.errMsg(block, src, "cast discards const qualifier", .{});
             errdefer msg.destroy(sema.gpa);
 
-            try sema.errNote(block, src, msg, "consider using '@qualCast'", .{});
+            try sema.errNote(block, src, msg, "consider using '@constCast'", .{});
             break :msg msg;
         };
         return sema.failWithOwnedErrorMsg(msg);
@@ -19550,7 +19556,7 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
             const msg = try sema.errMsg(block, src, "cast discards volatile qualifier", .{});
             errdefer msg.destroy(sema.gpa);
 
-            try sema.errNote(block, src, msg, "consider using '@qualCast'", .{});
+            try sema.errNote(block, src, msg, "consider using '@volatileCast'", .{});
             break :msg msg;
         };
         return sema.failWithOwnedErrorMsg(msg);
@@ -19655,40 +19661,37 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
     return block.addBitCast(aligned_dest_ty, ptr);
 }
 
-fn zirQualCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
-    const inst_data = sema.code.instructions.items(.data)[inst].pl_node;
-    const src = inst_data.src();
-    const dest_ty_src: LazySrcLoc = .{ .node_offset_builtin_call_arg0 = inst_data.src_node };
-    const operand_src: LazySrcLoc = .{ .node_offset_builtin_call_arg1 = inst_data.src_node };
-    const extra = sema.code.extraData(Zir.Inst.Bin, inst_data.payload_index).data;
-    const dest_ty = try sema.resolveType(block, dest_ty_src, extra.lhs);
-    const operand = try sema.resolveInst(extra.rhs);
+fn zirConstCast(sema: *Sema, block: *Block, extended: Zir.Inst.Extended.InstData) CompileError!Air.Inst.Ref {
+    const extra = sema.code.extraData(Zir.Inst.UnNode, extended.operand).data;
+    const src = LazySrcLoc.nodeOffset(extra.node);
+    const operand_src: LazySrcLoc = .{ .node_offset_builtin_call_arg0 = extra.node };
+    const operand = try sema.resolveInst(extra.operand);
     const operand_ty = sema.typeOf(operand);
-
-    try sema.checkPtrType(block, dest_ty_src, dest_ty);
     try sema.checkPtrOperand(block, operand_src, operand_ty);
 
-    var operand_payload = operand_ty.ptrInfo();
-    var dest_info = dest_ty.ptrInfo();
+    var ptr_info = operand_ty.ptrInfo().data;
+    ptr_info.mutable = true;
+    const dest_ty = try Type.ptr(sema.arena, sema.mod, ptr_info);
 
-    operand_payload.data.mutable = dest_info.data.mutable;
-    operand_payload.data.@"volatile" = dest_info.data.@"volatile";
+    if (try sema.resolveMaybeUndefVal(operand)) |operand_val| {
+        return sema.addConstant(dest_ty, operand_val);
+    }
 
-    const altered_operand_ty = Type.initPayload(&operand_payload.base);
-    if (!altered_operand_ty.eql(dest_ty, sema.mod)) {
-        const msg = msg: {
-            const msg = try sema.errMsg(block, src, "'@qualCast' can only modify 'const' and 'volatile' qualifiers", .{});
-            errdefer msg.destroy(sema.gpa);
+    try sema.requireRuntimeBlock(block, src, null);
+    return block.addBitCast(dest_ty, operand);
+}
 
-            dest_info.data.mutable = !operand_ty.isConstPtr();
-            dest_info.data.@"volatile" = operand_ty.isVolatilePtr();
-            const altered_dest_ty = Type.initPayload(&dest_info.base);
-            try sema.errNote(block, src, msg, "expected type '{}'", .{altered_dest_ty.fmt(sema.mod)});
-            try sema.errNote(block, src, msg, "got type '{}'", .{operand_ty.fmt(sema.mod)});
-            break :msg msg;
-        };
-        return sema.failWithOwnedErrorMsg(msg);
-    }
+fn zirVolatileCast(sema: *Sema, block: *Block, extended: Zir.Inst.Extended.InstData) CompileError!Air.Inst.Ref {
+    const extra = sema.code.extraData(Zir.Inst.UnNode, extended.operand).data;
+    const src = LazySrcLoc.nodeOffset(extra.node);
+    const operand_src: LazySrcLoc = .{ .node_offset_builtin_call_arg0 = extra.node };
+    const operand = try sema.resolveInst(extra.operand);
+    const operand_ty = sema.typeOf(operand);
+    try sema.checkPtrOperand(block, operand_src, operand_ty);
+
+    var ptr_info = operand_ty.ptrInfo().data;
+    ptr_info.@"volatile" = false;
+    const dest_ty = try Type.ptr(sema.arena, sema.mod, ptr_info);
 
     if (try sema.resolveMaybeUndefVal(operand)) |operand_val| {
         return sema.addConstant(dest_ty, operand_val);
@@ -21930,7 +21933,7 @@ fn zirCUndef(
     const src: LazySrcLoc = .{ .node_offset_builtin_call_arg0 = extra.node };
 
     const name = try sema.resolveConstString(block, src, extra.operand, "name of macro being undefined must be comptime-known");
-    try block.c_import_buf.?.writer().print("#undefine {s}\n", .{name});
+    try block.c_import_buf.?.writer().print("#undef {s}\n", .{name});
     return Air.Inst.Ref.void_value;
 }
 
@@ -29756,6 +29759,25 @@ fn resolvePeerTypes(
                     continue;
                 }
             },
+            .ErrorSet => {
+                chosen = candidate;
+                chosen_i = candidate_i + 1;
+                if (err_set_ty) |chosen_set_ty| {
+                    if (.ok == try sema.coerceInMemoryAllowedErrorSets(block, chosen_set_ty, chosen_ty, src, src)) {
+                        continue;
+                    }
+                    if (.ok == try sema.coerceInMemoryAllowedErrorSets(block, chosen_ty, chosen_set_ty, src, src)) {
+                        err_set_ty = chosen_ty;
+                        continue;
+                    }
+
+                    err_set_ty = try chosen_set_ty.errorSetMerge(sema.arena, chosen_ty);
+                    continue;
+                } else {
+                    err_set_ty = chosen_ty;
+                    continue;
+                }
+            },
             else => {},
         }
 
diff --git a/src/Zir.zig b/src/Zir.zig
index b93422177e..58f9fdff14 100644
--- a/src/Zir.zig
+++ b/src/Zir.zig
@@ -857,9 +857,6 @@ pub const Inst = struct {
         /// Implements the `@ptrCast` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
         ptr_cast,
-        /// Implements the `@qualCast` builtin.
-        /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
-        qual_cast,
         /// Implements the `@truncate` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
         truncate,
@@ -1198,7 +1195,6 @@ pub const Inst = struct {
                 .float_cast,
                 .int_cast,
                 .ptr_cast,
-                .qual_cast,
                 .truncate,
                 .align_cast,
                 .has_field,
@@ -1488,7 +1484,6 @@ pub const Inst = struct {
                 .float_cast,
                 .int_cast,
                 .ptr_cast,
-                .qual_cast,
                 .truncate,
                 .align_cast,
                 .has_field,
@@ -1760,7 +1755,6 @@ pub const Inst = struct {
                 .float_cast = .pl_node,
                 .int_cast = .pl_node,
                 .ptr_cast = .pl_node,
-                .qual_cast = .pl_node,
                 .truncate = .pl_node,
                 .align_cast = .pl_node,
                 .typeof_builtin = .pl_node,
@@ -2004,6 +1998,12 @@ pub const Inst = struct {
         /// Implement builtin `@cVaStart`.
         /// `operand` is `src_node: i32`.
         c_va_start,
+        /// Implements the `@constCast` builtin.
+        /// `operand` is payload index to `UnNode`.
+        const_cast,
+        /// Implements the `@volatileCast` builtin.
+        /// `operand` is payload index to `UnNode`.
+        volatile_cast,
 
         pub const InstData = struct {
             opcode: Extended,
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 6433191221..00f6c55171 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -2278,7 +2278,9 @@ pub const Object = struct {
 
                 const full_di_fields: [2]*llvm.DIType =
                     if (layout.tag_align >= layout.payload_align)
-                .{ tag_di, payload_di } else .{ payload_di, tag_di };
+                    .{ tag_di, payload_di }
+                else
+                    .{ payload_di, tag_di };
 
                 const full_di_ty = dib.createStructType(
                     compile_unit_scope,
@@ -4167,6 +4169,10 @@ pub const DeclGen = struct {
             if (func.data.owner_decl != decl_index) {
                 return self.lowerDeclRefValue(tv, func.data.owner_decl);
             }
+        } else if (decl.val.castTag(.extern_fn)) |func| {
+            if (func.data.owner_decl != decl_index) {
+                return self.lowerDeclRefValue(tv, func.data.owner_decl);
+            }
         }
 
         const is_fn_body = decl.ty.zigTypeTag() == .Fn;
diff --git a/src/glibc.zig b/src/glibc.zig
index 8dce1c5132..2a2887c334 100644
--- a/src/glibc.zig
+++ b/src/glibc.zig
@@ -11,7 +11,7 @@ const target_util = @import("target.zig");
 const Compilation = @import("Compilation.zig");
 const build_options = @import("build_options");
 const trace = @import("tracy.zig").trace;
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 const Package = @import("Package.zig");
 
 pub const Lib = struct {
diff --git a/src/link.zig b/src/link.zig
index 2b3ce51667..4c4915441d 100644
--- a/src/link.zig
+++ b/src/link.zig
@@ -10,7 +10,7 @@ const wasi_libc = @import("wasi_libc.zig");
 
 const Air = @import("Air.zig");
 const Allocator = std.mem.Allocator;
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 const Compilation = @import("Compilation.zig");
 const LibCInstallation = @import("libc_installation.zig").LibCInstallation;
 const Liveness = @import("Liveness.zig");
@@ -25,6 +25,8 @@ pub const SystemLib = struct {
     weak: bool = false,
 };
 
+pub const SortSection = enum { name, alignment };
+
 pub const CacheMode = enum { incremental, whole };
 
 pub fn hashAddSystemLibs(
@@ -159,6 +161,7 @@ pub const Options = struct {
     disable_lld_caching: bool,
     is_test: bool,
     hash_style: HashStyle,
+    sort_section: ?SortSection,
     major_subsystem_version: ?u32,
     minor_subsystem_version: ?u32,
     gc_sections: ?bool = null,
diff --git a/src/link/Coff/lld.zig b/src/link/Coff/lld.zig
index d705f62f5c..c308ff5989 100644
--- a/src/link/Coff/lld.zig
+++ b/src/link/Coff/lld.zig
@@ -5,6 +5,7 @@ const assert = std.debug.assert;
 const fs = std.fs;
 const log = std.log.scoped(.link);
 const mem = std.mem;
+const Cache = std.Build.Cache;
 
 const mingw = @import("../../mingw.zig");
 const link = @import("../../link.zig");
@@ -13,7 +14,6 @@ const trace = @import("../../tracy.zig").trace;
 
 const Allocator = mem.Allocator;
 
-const Cache = @import("../../Cache.zig");
 const Coff = @import("../Coff.zig");
 const Compilation = @import("../../Compilation.zig");
 
diff --git a/src/link/Elf.zig b/src/link/Elf.zig
index 45952da6c0..d936a347cf 100644
--- a/src/link/Elf.zig
+++ b/src/link/Elf.zig
@@ -21,7 +21,7 @@ const trace = @import("../tracy.zig").trace;
 const Air = @import("../Air.zig");
 const Allocator = std.mem.Allocator;
 pub const Atom = @import("Elf/Atom.zig");
-const Cache = @import("../Cache.zig");
+const Cache = std.Build.Cache;
 const Compilation = @import("../Compilation.zig");
 const Dwarf = @import("Dwarf.zig");
 const File = link.File;
@@ -1324,6 +1324,7 @@ fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !v
         man.hash.addOptionalBytes(self.base.options.entry);
         man.hash.addOptional(self.base.options.image_base_override);
         man.hash.add(gc_sections);
+        man.hash.addOptional(self.base.options.sort_section);
         man.hash.add(self.base.options.eh_frame_hdr);
         man.hash.add(self.base.options.emit_relocs);
         man.hash.add(self.base.options.rdynamic);
@@ -1488,6 +1489,11 @@ fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !v
             try argv.append(linker_script);
         }
 
+        if (self.base.options.sort_section) |how| {
+            const arg = try std.fmt.allocPrint(arena, "--sort-section={s}", .{@tagName(how)});
+            try argv.append(arg);
+        }
+
         if (gc_sections) {
             try argv.append("--gc-sections");
         }
diff --git a/src/link/MachO.zig b/src/link/MachO.zig
index 24ef275c5b..35f5f1b562 100644
--- a/src/link/MachO.zig
+++ b/src/link/MachO.zig
@@ -28,7 +28,7 @@ const Air = @import("../Air.zig");
 const Allocator = mem.Allocator;
 const Archive = @import("MachO/Archive.zig");
 pub const Atom = @import("MachO/Atom.zig");
-const Cache = @import("../Cache.zig");
+const Cache = std.Build.Cache;
 const CodeSignature = @import("MachO/CodeSignature.zig");
 const Compilation = @import("../Compilation.zig");
 const Dwarf = File.Dwarf;
diff --git a/src/link/MachO/Dylib.zig b/src/link/MachO/Dylib.zig
index 1c1842aaed..a2c4bad942 100644
--- a/src/link/MachO/Dylib.zig
+++ b/src/link/MachO/Dylib.zig
@@ -166,6 +166,8 @@ pub fn parseFromBinary(
                 const symtab_cmd = cmd.cast(macho.symtab_command).?;
                 const symtab = @ptrCast(
                     [*]const macho.nlist_64,
+                    // Alignment is guaranteed as a dylib is a final linked image and has to have sections
+                    // properly aligned in order to be correctly loaded by the loader.
                     @alignCast(@alignOf(macho.nlist_64), &data[symtab_cmd.symoff]),
                 )[0..symtab_cmd.nsyms];
                 const strtab = data[symtab_cmd.stroff..][0..symtab_cmd.strsize];
diff --git a/src/link/MachO/Object.zig b/src/link/MachO/Object.zig
index 13219084b6..4d24b2ed6a 100644
--- a/src/link/MachO/Object.zig
+++ b/src/link/MachO/Object.zig
@@ -60,14 +60,24 @@ globals_lookup: []i64 = undefined,
 /// Can be undefined as set together with in_symtab.
 relocs_lookup: []RelocEntry = undefined,
 
+/// All relocations sorted and flatened, sorted by address descending
+/// per section.
+relocations: std.ArrayListUnmanaged(macho.relocation_info) = .{},
+/// Beginning index to the relocations array for each input section
+/// defined within this Object file.
+section_relocs_lookup: std.ArrayListUnmanaged(u32) = .{},
+
+/// Data-in-code records sorted by address.
+data_in_code: std.ArrayListUnmanaged(macho.data_in_code_entry) = .{},
+
 atoms: std.ArrayListUnmanaged(AtomIndex) = .{},
 exec_atoms: std.ArrayListUnmanaged(AtomIndex) = .{},
 
-eh_frame_sect: ?macho.section_64 = null,
+eh_frame_sect_id: ?u8 = null,
 eh_frame_relocs_lookup: std.AutoArrayHashMapUnmanaged(u32, Record) = .{},
 eh_frame_records_lookup: std.AutoArrayHashMapUnmanaged(AtomIndex, u32) = .{},
 
-unwind_info_sect: ?macho.section_64 = null,
+unwind_info_sect_id: ?u8 = null,
 unwind_relocs_lookup: []Record = undefined,
 unwind_records_lookup: std.AutoHashMapUnmanaged(AtomIndex, u32) = .{},
 
@@ -100,6 +110,9 @@ pub fn deinit(self: *Object, gpa: Allocator) void {
         gpa.free(self.unwind_relocs_lookup);
     }
     self.unwind_records_lookup.deinit(gpa);
+    self.relocations.deinit(gpa);
+    self.section_relocs_lookup.deinit(gpa);
+    self.data_in_code.deinit(gpa);
 }
 
 pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch) !void {
@@ -137,15 +150,18 @@ pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch)
         .buffer = self.contents[@sizeOf(macho.mach_header_64)..][0..self.header.sizeofcmds],
     };
     const nsects = self.getSourceSections().len;
+
+    // Prepopulate relocations per section lookup table.
+    try self.section_relocs_lookup.resize(allocator, nsects);
+    mem.set(u32, self.section_relocs_lookup.items, 0);
+
+    // Parse symtab.
     const symtab = while (it.next()) |cmd| switch (cmd.cmd()) {
         .SYMTAB => break cmd.cast(macho.symtab_command).?,
         else => {},
     } else return;
 
-    self.in_symtab = @ptrCast(
-        [*]const macho.nlist_64,
-        @alignCast(@alignOf(macho.nlist_64), &self.contents[symtab.symoff]),
-    )[0..symtab.nsyms];
+    self.in_symtab = @ptrCast([*]align(1) const macho.nlist_64, self.contents.ptr + symtab.symoff)[0..symtab.nsyms];
     self.in_strtab = self.contents[symtab.stroff..][0..symtab.strsize];
 
     self.symtab = try allocator.alloc(macho.nlist_64, self.in_symtab.?.len + nsects);
@@ -212,10 +228,10 @@ pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch)
     }
 
     // Parse __TEXT,__eh_frame header if one exists
-    self.eh_frame_sect = self.getSourceSectionByName("__TEXT", "__eh_frame");
+    self.eh_frame_sect_id = self.getSourceSectionIndexByName("__TEXT", "__eh_frame");
 
     // Parse __LD,__compact_unwind header if one exists
-    self.unwind_info_sect = self.getSourceSectionByName("__LD", "__compact_unwind");
+    self.unwind_info_sect_id = self.getSourceSectionIndexByName("__LD", "__compact_unwind");
     if (self.hasUnwindRecords()) {
         self.unwind_relocs_lookup = try allocator.alloc(Record, self.getUnwindRecords().len);
         mem.set(Record, self.unwind_relocs_lookup, .{
@@ -354,6 +370,7 @@ pub fn splitIntoAtoms(self: *Object, zld: *Zld, object_id: u32) !void {
     try self.splitRegularSections(zld, object_id);
     try self.parseEhFrameSection(zld, object_id);
     try self.parseUnwindInfo(zld, object_id);
+    try self.parseDataInCode(zld.gpa);
 }
 
 /// Splits input regular sections into Atoms.
@@ -452,6 +469,8 @@ pub fn splitRegularSections(self: *Object, zld: *Zld, object_id: u32) !void {
             zld.sections.items(.header)[out_sect_id].sectName(),
         });
 
+        try self.parseRelocs(gpa, section.id);
+
         const cpu_arch = zld.options.target.cpu.arch;
         const sect_loc = filterSymbolsBySection(symtab[sect_sym_index..], sect_id + 1);
         const sect_start_index = sect_sym_index + sect_loc.index;
@@ -623,25 +642,36 @@ fn filterRelocs(
     return .{ .start = @intCast(u32, start), .len = @intCast(u32, len) };
 }
 
+/// Parse all relocs for the input section, and sort in descending order.
+/// Previously, I have wrongly assumed the compilers output relocations for each
+/// section in a sorted manner which is simply not true.
+fn parseRelocs(self: *Object, gpa: Allocator, sect_id: u8) !void {
+    const section = self.getSourceSection(sect_id);
+    const start = @intCast(u32, self.relocations.items.len);
+    if (self.getSourceRelocs(section)) |relocs| {
+        try self.relocations.ensureUnusedCapacity(gpa, relocs.len);
+        self.relocations.appendUnalignedSliceAssumeCapacity(relocs);
+        std.sort.sort(macho.relocation_info, self.relocations.items[start..], {}, relocGreaterThan);
+    }
+    self.section_relocs_lookup.items[sect_id] = start;
+}
+
 fn cacheRelocs(self: *Object, zld: *Zld, atom_index: AtomIndex) !void {
     const atom = zld.getAtom(atom_index);
 
-    const source_sect = if (self.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
-        const source_sect = self.getSourceSection(source_sym.n_sect - 1);
-        assert(!source_sect.isZerofill());
-        break :blk source_sect;
+    const source_sect_id = if (self.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
+        break :blk source_sym.n_sect - 1;
     } else blk: {
         // If there was no matching symbol present in the source symtab, this means
         // we are dealing with either an entire section, or part of it, but also
         // starting at the beginning.
         const nbase = @intCast(u32, self.in_symtab.?.len);
-        const sect_id = @intCast(u16, atom.sym_index - nbase);
-        const source_sect = self.getSourceSection(sect_id);
-        assert(!source_sect.isZerofill());
-        break :blk source_sect;
+        const sect_id = @intCast(u8, atom.sym_index - nbase);
+        break :blk sect_id;
     };
-
-    const relocs = self.getRelocs(source_sect);
+    const source_sect = self.getSourceSection(source_sect_id);
+    assert(!source_sect.isZerofill());
+    const relocs = self.getRelocs(source_sect_id);
 
     self.relocs_lookup[atom.sym_index] = if (self.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
         const offset = source_sym.n_value - source_sect.addr;
@@ -649,8 +679,14 @@ fn cacheRelocs(self: *Object, zld: *Zld, atom_index: AtomIndex) !void {
     } else filterRelocs(relocs, 0, atom.size);
 }
 
+fn relocGreaterThan(ctx: void, lhs: macho.relocation_info, rhs: macho.relocation_info) bool {
+    _ = ctx;
+    return lhs.r_address > rhs.r_address;
+}
+
 fn parseEhFrameSection(self: *Object, zld: *Zld, object_id: u32) !void {
-    const sect = self.eh_frame_sect orelse return;
+    const sect_id = self.eh_frame_sect_id orelse return;
+    const sect = self.getSourceSection(sect_id);
 
     log.debug("parsing __TEXT,__eh_frame section", .{});
 
@@ -660,7 +696,8 @@ fn parseEhFrameSection(self: *Object, zld: *Zld, object_id: u32) !void {
 
     const gpa = zld.gpa;
     const cpu_arch = zld.options.target.cpu.arch;
-    const relocs = self.getRelocs(sect);
+    try self.parseRelocs(gpa, sect_id);
+    const relocs = self.getRelocs(sect_id);
 
     var it = self.getEhFrameRecordsIterator();
     var record_count: u32 = 0;
@@ -728,12 +765,12 @@ fn parseEhFrameSection(self: *Object, zld: *Zld, object_id: u32) !void {
 }
 
 fn parseUnwindInfo(self: *Object, zld: *Zld, object_id: u32) !void {
-    const sect = self.unwind_info_sect orelse {
+    const sect_id = self.unwind_info_sect_id orelse {
         // If it so happens that the object had `__eh_frame` section defined but no `__compact_unwind`,
         // we will try fully synthesising unwind info records to somewhat match Apple ld's
         // approach. However, we will only synthesise DWARF records and nothing more. For this reason,
         // we still create the output `__TEXT,__unwind_info` section.
-        if (self.eh_frame_sect != null) {
+        if (self.hasEhFrameRecords()) {
             if (zld.getSectionByName("__TEXT", "__unwind_info") == null) {
                 _ = try zld.initSection("__TEXT", "__unwind_info", .{});
             }
@@ -758,15 +795,15 @@ fn parseUnwindInfo(self: *Object, zld: *Zld, object_id: u32) !void {
         if (UnwindInfo.UnwindEncoding.isDwarf(record.compactUnwindEncoding, cpu_arch)) break true;
     } else false;
 
-    if (needs_eh_frame) {
-        if (self.eh_frame_sect == null) {
-            log.err("missing __TEXT,__eh_frame section", .{});
-            log.err("  in object {s}", .{self.name});
-            return error.MissingSection;
-        }
+    if (needs_eh_frame and !self.hasEhFrameRecords()) {
+        log.err("missing __TEXT,__eh_frame section", .{});
+        log.err("  in object {s}", .{self.name});
+        return error.MissingSection;
     }
 
-    const relocs = self.getRelocs(sect);
+    try self.parseRelocs(gpa, sect_id);
+    const relocs = self.getRelocs(sect_id);
+
     for (unwind_records) |record, record_id| {
         const offset = record_id * @sizeOf(macho.compact_unwind_entry);
         const rel_pos = filterRelocs(
@@ -806,25 +843,23 @@ pub fn getSourceSymbol(self: Object, index: u32) ?macho.nlist_64 {
     return symtab[mapped_index];
 }
 
-pub fn getSourceSection(self: Object, index: u16) macho.section_64 {
+pub fn getSourceSection(self: Object, index: u8) macho.section_64 {
     const sections = self.getSourceSections();
     assert(index < sections.len);
     return sections[index];
 }
 
 pub fn getSourceSectionByName(self: Object, segname: []const u8, sectname: []const u8) ?macho.section_64 {
+    const index = self.getSourceSectionIndexByName(segname, sectname) orelse return null;
     const sections = self.getSourceSections();
-    for (sections) |sect| {
-        if (mem.eql(u8, segname, sect.segName()) and mem.eql(u8, sectname, sect.sectName()))
-            return sect;
-    } else return null;
+    return sections[index];
 }
 
 pub fn getSourceSectionIndexByName(self: Object, segname: []const u8, sectname: []const u8) ?u8 {
     const sections = self.getSourceSections();
     for (sections) |sect, i| {
         if (mem.eql(u8, segname, sect.segName()) and mem.eql(u8, sectname, sect.sectName()))
-            return @intCast(u8, i + 1);
+            return @intCast(u8, i);
     } else return null;
 }
 
@@ -841,24 +876,27 @@ pub fn getSourceSections(self: Object) []const macho.section_64 {
     } else unreachable;
 }
 
-pub fn parseDataInCode(self: Object) ?[]const macho.data_in_code_entry {
+pub fn parseDataInCode(self: *Object, gpa: Allocator) !void {
     var it = LoadCommandIterator{
         .ncmds = self.header.ncmds,
         .buffer = self.contents[@sizeOf(macho.mach_header_64)..][0..self.header.sizeofcmds],
     };
-    while (it.next()) |cmd| {
+    const cmd = while (it.next()) |cmd| {
         switch (cmd.cmd()) {
-            .DATA_IN_CODE => {
-                const dice = cmd.cast(macho.linkedit_data_command).?;
-                const ndice = @divExact(dice.datasize, @sizeOf(macho.data_in_code_entry));
-                return @ptrCast(
-                    [*]const macho.data_in_code_entry,
-                    @alignCast(@alignOf(macho.data_in_code_entry), &self.contents[dice.dataoff]),
-                )[0..ndice];
-            },
+            .DATA_IN_CODE => break cmd.cast(macho.linkedit_data_command).?,
             else => {},
         }
-    } else return null;
+    } else return;
+    const ndice = @divExact(cmd.datasize, @sizeOf(macho.data_in_code_entry));
+    const dice = @ptrCast([*]align(1) const macho.data_in_code_entry, self.contents.ptr + cmd.dataoff)[0..ndice];
+    try self.data_in_code.ensureTotalCapacityPrecise(gpa, dice.len);
+    self.data_in_code.appendUnalignedSliceAssumeCapacity(dice);
+    std.sort.sort(macho.data_in_code_entry, self.data_in_code.items, {}, diceLessThan);
+}
+
+fn diceLessThan(ctx: void, lhs: macho.data_in_code_entry, rhs: macho.data_in_code_entry) bool {
+    _ = ctx;
+    return lhs.offset < rhs.offset;
 }
 
 fn parseDysymtab(self: Object) ?macho.dysymtab_command {
@@ -914,11 +952,18 @@ pub fn getSectionAliasSymbolPtr(self: *Object, sect_id: u8) *macho.nlist_64 {
     return &self.symtab[self.getSectionAliasSymbolIndex(sect_id)];
 }
 
-pub fn getRelocs(self: Object, sect: macho.section_64) []align(1) const macho.relocation_info {
-    if (sect.nreloc == 0) return &[0]macho.relocation_info{};
+fn getSourceRelocs(self: Object, sect: macho.section_64) ?[]align(1) const macho.relocation_info {
+    if (sect.nreloc == 0) return null;
     return @ptrCast([*]align(1) const macho.relocation_info, self.contents.ptr + sect.reloff)[0..sect.nreloc];
 }
 
+pub fn getRelocs(self: Object, sect_id: u8) []const macho.relocation_info {
+    const sect = self.getSourceSection(sect_id);
+    const start = self.section_relocs_lookup.items[sect_id];
+    const len = sect.nreloc;
+    return self.relocations.items[start..][0..len];
+}
+
 pub fn getSymbolName(self: Object, index: u32) []const u8 {
     const strtab = self.in_strtab.?;
     const sym = self.symtab[index];
@@ -976,22 +1021,28 @@ pub fn getAtomIndexForSymbol(self: Object, sym_index: u32) ?AtomIndex {
 }
 
 pub fn hasUnwindRecords(self: Object) bool {
-    return self.unwind_info_sect != null;
+    return self.unwind_info_sect_id != null;
 }
 
 pub fn getUnwindRecords(self: Object) []align(1) const macho.compact_unwind_entry {
-    const sect = self.unwind_info_sect orelse return &[0]macho.compact_unwind_entry{};
+    const sect_id = self.unwind_info_sect_id orelse return &[0]macho.compact_unwind_entry{};
+    const sect = self.getSourceSection(sect_id);
     const data = self.getSectionContents(sect);
     const num_entries = @divExact(data.len, @sizeOf(macho.compact_unwind_entry));
     return @ptrCast([*]align(1) const macho.compact_unwind_entry, data)[0..num_entries];
 }
 
 pub fn hasEhFrameRecords(self: Object) bool {
-    return self.eh_frame_sect != null;
+    return self.eh_frame_sect_id != null;
 }
 
 pub fn getEhFrameRecordsIterator(self: Object) eh_frame.Iterator {
-    const sect = self.eh_frame_sect orelse return .{ .data = &[0]u8{} };
+    const sect_id = self.eh_frame_sect_id orelse return .{ .data = &[0]u8{} };
+    const sect = self.getSourceSection(sect_id);
     const data = self.getSectionContents(sect);
     return .{ .data = data };
 }
+
+pub fn hasDataInCode(self: Object) bool {
+    return self.data_in_code.items.len > 0;
+}
diff --git a/src/link/MachO/UnwindInfo.zig b/src/link/MachO/UnwindInfo.zig
index 07091af08a..5e61834bbc 100644
--- a/src/link/MachO/UnwindInfo.zig
+++ b/src/link/MachO/UnwindInfo.zig
@@ -68,7 +68,7 @@ const Page = struct {
     start: RecordIndex,
     count: u16,
     page_encodings: [max_compact_encodings]RecordIndex = undefined,
-    page_encodings_count: u8 = 0,
+    page_encodings_count: u9 = 0,
 
     fn appendPageEncoding(page: *Page, record_id: RecordIndex) void {
         assert(page.page_encodings_count <= max_compact_encodings);
@@ -81,13 +81,13 @@ const Page = struct {
         info: *const UnwindInfo,
         enc: macho.compact_unwind_encoding_t,
     ) ?u8 {
-        comptime var index: u8 = 0;
+        comptime var index: u9 = 0;
         inline while (index < max_compact_encodings) : (index += 1) {
             if (index >= page.page_encodings_count) return null;
             const record_id = page.page_encodings[index];
             const record = info.records.items[record_id];
             if (record.compactUnwindEncoding == enc) {
-                return index;
+                return @intCast(u8, index);
             }
         }
         return null;
@@ -703,15 +703,11 @@ pub fn parseRelocTarget(
     } else return sym_loc;
 }
 
-fn getRelocs(
-    zld: *Zld,
-    object_id: u32,
-    record_id: usize,
-) []align(1) const macho.relocation_info {
+fn getRelocs(zld: *Zld, object_id: u32, record_id: usize) []const macho.relocation_info {
     const object = &zld.objects.items[object_id];
     assert(object.hasUnwindRecords());
     const rel_pos = object.unwind_relocs_lookup[record_id].reloc;
-    const relocs = object.getRelocs(object.unwind_info_sect.?);
+    const relocs = object.getRelocs(object.unwind_info_sect_id.?);
     return relocs[rel_pos.start..][0..rel_pos.len];
 }
 
diff --git a/src/link/MachO/ZldAtom.zig b/src/link/MachO/ZldAtom.zig
index bb8b7cffb3..e3d5f62a12 100644
--- a/src/link/MachO/ZldAtom.zig
+++ b/src/link/MachO/ZldAtom.zig
@@ -143,7 +143,7 @@ pub fn calcInnerSymbolOffset(zld: *Zld, atom_index: AtomIndex, sym_index: u32) u
         sym.n_value
     else blk: {
         const nbase = @intCast(u32, object.in_symtab.?.len);
-        const sect_id = @intCast(u16, atom.sym_index - nbase);
+        const sect_id = @intCast(u8, atom.sym_index - nbase);
         const source_sect = object.getSourceSection(sect_id);
         break :blk source_sect.addr;
     };
@@ -180,7 +180,7 @@ pub fn getRelocContext(zld: *Zld, atom_index: AtomIndex) RelocContext {
         };
     }
     const nbase = @intCast(u32, object.in_symtab.?.len);
-    const sect_id = @intCast(u16, atom.sym_index - nbase);
+    const sect_id = @intCast(u8, atom.sym_index - nbase);
     const source_sect = object.getSourceSection(sect_id);
     return .{
         .base_addr = source_sect.addr,
@@ -724,7 +724,7 @@ fn resolveRelocsArm64(
 
                 if (rel.r_extern == 0) {
                     const base_addr = if (target.sym_index > object.source_address_lookup.len)
-                        @intCast(i64, object.getSourceSection(@intCast(u16, rel.r_symbolnum - 1)).addr)
+                        @intCast(i64, object.getSourceSection(@intCast(u8, rel.r_symbolnum - 1)).addr)
                     else
                         object.source_address_lookup[target.sym_index];
                     ptr_addend -= base_addr;
@@ -861,7 +861,7 @@ fn resolveRelocsX86(
 
                 if (rel.r_extern == 0) {
                     const base_addr = if (target.sym_index > object.source_address_lookup.len)
-                        @intCast(i64, object.getSourceSection(@intCast(u16, rel.r_symbolnum - 1)).addr)
+                        @intCast(i64, object.getSourceSection(@intCast(u8, rel.r_symbolnum - 1)).addr)
                     else
                         object.source_address_lookup[target.sym_index];
                     addend += @intCast(i32, @intCast(i64, context.base_addr) + rel.r_address + 4 -
@@ -884,7 +884,7 @@ fn resolveRelocsX86(
 
                 if (rel.r_extern == 0) {
                     const base_addr = if (target.sym_index > object.source_address_lookup.len)
-                        @intCast(i64, object.getSourceSection(@intCast(u16, rel.r_symbolnum - 1)).addr)
+                        @intCast(i64, object.getSourceSection(@intCast(u8, rel.r_symbolnum - 1)).addr)
                     else
                         object.source_address_lookup[target.sym_index];
                     addend -= base_addr;
@@ -928,7 +928,7 @@ pub fn getAtomCode(zld: *Zld, atom_index: AtomIndex) []const u8 {
         // we are dealing with either an entire section, or part of it, but also
         // starting at the beginning.
         const nbase = @intCast(u32, object.in_symtab.?.len);
-        const sect_id = @intCast(u16, atom.sym_index - nbase);
+        const sect_id = @intCast(u8, atom.sym_index - nbase);
         const source_sect = object.getSourceSection(sect_id);
         assert(!source_sect.isZerofill());
         const code = object.getSectionContents(source_sect);
@@ -943,28 +943,25 @@ pub fn getAtomCode(zld: *Zld, atom_index: AtomIndex) []const u8 {
     return code[offset..][0..code_len];
 }
 
-pub fn getAtomRelocs(zld: *Zld, atom_index: AtomIndex) []align(1) const macho.relocation_info {
+pub fn getAtomRelocs(zld: *Zld, atom_index: AtomIndex) []const macho.relocation_info {
     const atom = zld.getAtom(atom_index);
     assert(atom.getFile() != null); // Synthetic atom shouldn't need to unique for relocs.
     const object = zld.objects.items[atom.getFile().?];
     const cache = object.relocs_lookup[atom.sym_index];
 
-    const source_sect = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
-        const source_sect = object.getSourceSection(source_sym.n_sect - 1);
-        assert(!source_sect.isZerofill());
-        break :blk source_sect;
+    const source_sect_id = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
+        break :blk source_sym.n_sect - 1;
     } else blk: {
         // If there was no matching symbol present in the source symtab, this means
         // we are dealing with either an entire section, or part of it, but also
         // starting at the beginning.
         const nbase = @intCast(u32, object.in_symtab.?.len);
-        const sect_id = @intCast(u16, atom.sym_index - nbase);
-        const source_sect = object.getSourceSection(sect_id);
-        assert(!source_sect.isZerofill());
-        break :blk source_sect;
+        const sect_id = @intCast(u8, atom.sym_index - nbase);
+        break :blk sect_id;
     };
-
-    const relocs = object.getRelocs(source_sect);
+    const source_sect = object.getSourceSection(source_sect_id);
+    assert(!source_sect.isZerofill());
+    const relocs = object.getRelocs(source_sect_id);
     return relocs[cache.start..][0..cache.len];
 }
 
diff --git a/src/link/MachO/dead_strip.zig b/src/link/MachO/dead_strip.zig
index 1f8def96f3..6ba70acbfd 100644
--- a/src/link/MachO/dead_strip.zig
+++ b/src/link/MachO/dead_strip.zig
@@ -88,7 +88,7 @@ fn collectRoots(zld: *Zld, roots: *AtomTable) !void {
                     source_sym.n_sect - 1
                 else sect_id: {
                     const nbase = @intCast(u32, object.in_symtab.?.len);
-                    const sect_id = @intCast(u16, atom.sym_index - nbase);
+                    const sect_id = @intCast(u8, atom.sym_index - nbase);
                     break :sect_id sect_id;
                 };
                 const source_sect = object.getSourceSection(sect_id);
@@ -223,7 +223,7 @@ fn mark(zld: *Zld, roots: AtomTable, alive: *AtomTable) !void {
                     source_sym.n_sect - 1
                 else blk: {
                     const nbase = @intCast(u32, object.in_symtab.?.len);
-                    const sect_id = @intCast(u16, atom.sym_index - nbase);
+                    const sect_id = @intCast(u8, atom.sym_index - nbase);
                     break :blk sect_id;
                 };
                 const source_sect = object.getSourceSection(sect_id);
@@ -350,8 +350,9 @@ fn markEhFrameRecord(zld: *Zld, object_id: u32, atom_index: AtomIndex, alive: *A
             }
         },
         .x86_64 => {
+            const sect = object.getSourceSection(object.eh_frame_sect_id.?);
             const lsda_ptr = try fde.getLsdaPointer(cie, .{
-                .base_addr = object.eh_frame_sect.?.addr,
+                .base_addr = sect.addr,
                 .base_offset = fde_offset,
             });
             if (lsda_ptr) |lsda_address| {
diff --git a/src/link/MachO/eh_frame.zig b/src/link/MachO/eh_frame.zig
index 8345a8e4f3..3867b15a96 100644
--- a/src/link/MachO/eh_frame.zig
+++ b/src/link/MachO/eh_frame.zig
@@ -171,8 +171,9 @@ pub fn write(zld: *Zld, unwind_info: *UnwindInfo) !void {
                     const cie_record = eh_records.get(
                         eh_frame_offset + 4 - fde_record.getCiePointer(),
                     ).?;
+                    const eh_frame_sect = object.getSourceSection(object.eh_frame_sect_id.?);
                     const source_lsda_ptr = try fde_record.getLsdaPointer(cie_record, .{
-                        .base_addr = object.eh_frame_sect.?.addr,
+                        .base_addr = eh_frame_sect.addr,
                         .base_offset = fde_record_offset,
                     });
                     if (source_lsda_ptr) |ptr| {
@@ -552,16 +553,12 @@ pub fn EhFrameRecord(comptime is_mutable: bool) type {
     };
 }
 
-pub fn getRelocs(
-    zld: *Zld,
-    object_id: u32,
-    source_offset: u32,
-) []align(1) const macho.relocation_info {
+pub fn getRelocs(zld: *Zld, object_id: u32, source_offset: u32) []const macho.relocation_info {
     const object = &zld.objects.items[object_id];
     assert(object.hasEhFrameRecords());
     const urel = object.eh_frame_relocs_lookup.get(source_offset) orelse
         return &[0]macho.relocation_info{};
-    const all_relocs = object.getRelocs(object.eh_frame_sect.?);
+    const all_relocs = object.getRelocs(object.eh_frame_sect_id.?);
     return all_relocs[urel.reloc.start..][0..urel.reloc.len];
 }
 
diff --git a/src/link/MachO/zld.zig b/src/link/MachO/zld.zig
index 81fae399ef..a94a0828fc 100644
--- a/src/link/MachO/zld.zig
+++ b/src/link/MachO/zld.zig
@@ -20,7 +20,7 @@ const trace = @import("../../tracy.zig").trace;
 const Allocator = mem.Allocator;
 const Archive = @import("Archive.zig");
 const Atom = @import("ZldAtom.zig");
-const Cache = @import("../../Cache.zig");
+const Cache = std.Build.Cache;
 const CodeSignature = @import("CodeSignature.zig");
 const Compilation = @import("../../Compilation.zig");
 const DwarfInfo = @import("DwarfInfo.zig");
@@ -1065,7 +1065,13 @@ pub const Zld = struct {
                 assert(offsets.items.len > 0);
 
                 const object_id = @intCast(u16, self.objects.items.len);
-                const object = try archive.parseObject(gpa, cpu_arch, offsets.items[0]);
+                const object = archive.parseObject(gpa, cpu_arch, offsets.items[0]) catch |e| switch (e) {
+                    error.MismatchedCpuArchitecture => {
+                        log.err("CPU architecture mismatch found in {s}", .{archive.name});
+                        return e;
+                    },
+                    else => return e,
+                };
                 try self.objects.append(gpa, object);
                 try self.resolveSymbolsInObject(object_id, resolver);
 
@@ -2391,22 +2397,20 @@ pub const Zld = struct {
         const text_sect_header = self.sections.items(.header)[text_sect_id];
 
         for (self.objects.items) |object| {
-            const dice = object.parseDataInCode() orelse continue;
+            if (!object.hasDataInCode()) continue;
+            const dice = object.data_in_code.items;
             try out_dice.ensureUnusedCapacity(dice.len);
 
-            for (object.atoms.items) |atom_index| {
+            for (object.exec_atoms.items) |atom_index| {
                 const atom = self.getAtom(atom_index);
                 const sym = self.getSymbol(atom.getSymbolWithLoc());
-                const sect_id = sym.n_sect - 1;
-                if (sect_id != text_sect_id) {
-                    continue;
-                }
+                if (sym.n_desc == N_DEAD) continue;
 
                 const source_addr = if (object.getSourceSymbol(atom.sym_index)) |source_sym|
                     source_sym.n_value
                 else blk: {
                     const nbase = @intCast(u32, object.in_symtab.?.len);
-                    const source_sect_id = @intCast(u16, atom.sym_index - nbase);
+                    const source_sect_id = @intCast(u8, atom.sym_index - nbase);
                     break :blk object.getSourceSection(source_sect_id).addr;
                 };
                 const filtered_dice = filterDataInCode(dice, source_addr, source_addr + atom.size);
@@ -2699,12 +2703,12 @@ pub const Zld = struct {
                     // Exclude region comprising all symbol stabs.
                     const nlocals = self.dysymtab_cmd.nlocalsym;
 
-                    const locals_buf = try self.gpa.alloc(u8, nlocals * @sizeOf(macho.nlist_64));
-                    defer self.gpa.free(locals_buf);
+                    const locals = try self.gpa.alloc(macho.nlist_64, nlocals);
+                    defer self.gpa.free(locals);
 
+                    const locals_buf = @ptrCast([*]u8, locals.ptr)[0 .. @sizeOf(macho.nlist_64) * nlocals];
                     const amt = try self.file.preadAll(locals_buf, self.symtab_cmd.symoff);
                     if (amt != locals_buf.len) return error.InputOutput;
-                    const locals = @ptrCast([*]macho.nlist_64, @alignCast(@alignOf(macho.nlist_64), locals_buf))[0..nlocals];
 
                     const istab: usize = for (locals) |local, i| {
                         if (local.stab()) break i;
diff --git a/src/link/Wasm.zig b/src/link/Wasm.zig
index 9d20412788..e62a2050d7 100644
--- a/src/link/Wasm.zig
+++ b/src/link/Wasm.zig
@@ -20,7 +20,7 @@ const lldMain = @import("../main.zig").lldMain;
 const trace = @import("../tracy.zig").trace;
 const build_options = @import("build_options");
 const wasi_libc = @import("../wasi_libc.zig");
-const Cache = @import("../Cache.zig");
+const Cache = std.Build.Cache;
 const Type = @import("../type.zig").Type;
 const TypedValue = @import("../TypedValue.zig");
 const LlvmObject = @import("../codegen/llvm.zig").Object;
diff --git a/src/main.zig b/src/main.zig
index f634c259ff..a0cdfb36b6 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -20,7 +20,7 @@ const LibCInstallation = @import("libc_installation.zig").LibCInstallation;
 const wasi_libc = @import("wasi_libc.zig");
 const translate_c = @import("translate_c.zig");
 const clang = @import("clang.zig");
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 const target_util = @import("target.zig");
 const ThreadPool = @import("ThreadPool.zig");
 const crash_report = @import("crash_report.zig");
@@ -432,6 +432,8 @@ const usage_build_generic =
     \\  -fno-Clang                Prevent using Clang as the C/C++ compilation backend
     \\  -freference-trace[=num]   How many lines of reference trace should be shown per compile error
     \\  -fno-reference-trace      Disable reference trace
+    \\  -ferror-tracing           Enable error tracing in ReleaseFast mode
+    \\  -fno-error-tracing        Disable error tracing in Debug and ReleaseSafe mode
     \\  -fsingle-threaded         Code assumes there is only one thread
     \\  -fno-single-threaded      Code may not assume there is only one thread
     \\  -fbuiltin                 Enable implicit builtin knowledge of functions
@@ -490,6 +492,7 @@ const usage_build_generic =
     \\    nodelete                     Indicate that the object cannot be deleted from a process
     \\    notext                       Permit read-only relocations in read-only segments
     \\    defs                         Force a fatal error if any undefined symbols remain
+    \\    undefs                       Reverse of -z defs
     \\    origin                       Indicate that the object must have its origin processed
     \\    nocopyreloc                  Disable the creation of copy relocations
     \\    now                          (default) Force all relocations to be processed on load
@@ -506,6 +509,7 @@ const usage_build_generic =
     \\      zlib                       Compression with deflate/inflate
     \\  --gc-sections                  Force removal of functions and data that are unreachable by the entry point or exported symbols
     \\  --no-gc-sections               Don't force removal of unreachable functions and data
+    \\  --sort-section=[value]         Sort wildcard section patterns by 'name' or 'alignment'
     \\  --subsystem [subsystem]        (Windows) /SUBSYSTEM:<subsystem> to the linker
     \\  --stack [size]                 Override default stack size
     \\  --image-base [addr]            Set base address for executable image
@@ -728,6 +732,7 @@ fn buildOutputType(
     var linker_script: ?[]const u8 = null;
     var version_script: ?[]const u8 = null;
     var disable_c_depfile = false;
+    var linker_sort_section: ?link.SortSection = null;
     var linker_gc_sections: ?bool = null;
     var linker_compress_debug_sections: ?link.CompressDebugSections = null;
     var linker_allow_shlib_undefined: ?bool = null;
@@ -797,6 +802,7 @@ fn buildOutputType(
     var headerpad_max_install_names: bool = false;
     var dead_strip_dylibs: bool = false;
     var reference_trace: ?u32 = null;
+    var error_tracing: ?bool = null;
     var pdb_out_path: ?[]const u8 = null;
 
     // e.g. -m3dnow or -mno-outline-atomics. They correspond to std.Target llvm cpu feature names.
@@ -1218,6 +1224,10 @@ fn buildOutputType(
                         };
                     } else if (mem.eql(u8, arg, "-fno-reference-trace")) {
                         reference_trace = null;
+                    } else if (mem.eql(u8, arg, "-ferror-tracing")) {
+                        error_tracing = true;
+                    } else if (mem.eql(u8, arg, "-fno-error-tracing")) {
+                        error_tracing = false;
                     } else if (mem.eql(u8, arg, "-rdynamic")) {
                         rdynamic = true;
                     } else if (mem.eql(u8, arg, "-fsoname")) {
@@ -1326,6 +1336,8 @@ fn buildOutputType(
                             linker_z_notext = true;
                         } else if (mem.eql(u8, z_arg, "defs")) {
                             linker_z_defs = true;
+                        } else if (mem.eql(u8, z_arg, "undefs")) {
+                            linker_z_defs = false;
                         } else if (mem.eql(u8, z_arg, "origin")) {
                             linker_z_origin = true;
                         } else if (mem.eql(u8, z_arg, "nocopyreloc")) {
@@ -1343,7 +1355,7 @@ fn buildOutputType(
                         } else if (mem.startsWith(u8, z_arg, "max-page-size=")) {
                             linker_z_max_page_size = parseIntSuffix(z_arg, "max-page-size=".len);
                         } else {
-                            warn("unsupported linker extension flag: -z {s}", .{z_arg});
+                            fatal("unsupported linker extension flag: -z {s}", .{z_arg});
                         }
                     } else if (mem.eql(u8, arg, "--import-memory")) {
                         linker_import_memory = true;
@@ -1607,6 +1619,10 @@ fn buildOutputType(
                                         build_id = true;
                                         warn("ignoring build-id style argument: '{s}'", .{value});
                                         continue;
+                                    } else if (mem.eql(u8, key, "--sort-common")) {
+                                        // this ignores --sort=common=<anything>; ignoring plain --sort-common
+                                        // is done below.
+                                        continue;
                                     }
                                     try linker_args.append(key);
                                     try linker_args.append(value);
@@ -1619,6 +1635,9 @@ fn buildOutputType(
                                 needed = true;
                             } else if (mem.eql(u8, linker_arg, "-no-pie")) {
                                 want_pie = false;
+                            } else if (mem.eql(u8, linker_arg, "--sort-common")) {
+                                // from ld.lld(1): --sort-common is ignored for GNU compatibility,
+                                // this ignores plain --sort-common
                             } else if (mem.eql(u8, linker_arg, "--whole-archive") or
                                 mem.eql(u8, linker_arg, "-whole-archive"))
                             {
@@ -1872,6 +1891,8 @@ fn buildOutputType(
                     linker_gc_sections = true;
                 } else if (mem.eql(u8, arg, "-dead_strip_dylibs")) {
                     dead_strip_dylibs = true;
+                } else if (mem.eql(u8, arg, "--no-undefined")) {
+                    linker_z_defs = true;
                 } else if (mem.eql(u8, arg, "--gc-sections")) {
                     linker_gc_sections = true;
                 } else if (mem.eql(u8, arg, "--no-gc-sections")) {
@@ -1882,6 +1903,15 @@ fn buildOutputType(
                     linker_print_icf_sections = true;
                 } else if (mem.eql(u8, arg, "--print-map")) {
                     linker_print_map = true;
+                } else if (mem.eql(u8, arg, "--sort-section")) {
+                    i += 1;
+                    if (i >= linker_args.items.len) {
+                        fatal("expected linker arg after '{s}'", .{arg});
+                    }
+                    const arg1 = linker_args.items[i];
+                    linker_sort_section = std.meta.stringToEnum(link.SortSection, arg1) orelse {
+                        fatal("expected [name|alignment] after --sort-section, found '{s}'", .{arg1});
+                    };
                 } else if (mem.eql(u8, arg, "--allow-shlib-undefined") or
                     mem.eql(u8, arg, "-allow-shlib-undefined"))
                 {
@@ -1937,6 +1967,8 @@ fn buildOutputType(
                         linker_z_notext = true;
                     } else if (mem.eql(u8, z_arg, "defs")) {
                         linker_z_defs = true;
+                    } else if (mem.eql(u8, z_arg, "undefs")) {
+                        linker_z_defs = false;
                     } else if (mem.eql(u8, z_arg, "origin")) {
                         linker_z_origin = true;
                     } else if (mem.eql(u8, z_arg, "nocopyreloc")) {
@@ -1961,7 +1993,7 @@ fn buildOutputType(
                     } else if (mem.startsWith(u8, z_arg, "max-page-size=")) {
                         linker_z_max_page_size = parseIntSuffix(z_arg, "max-page-size=".len);
                     } else {
-                        warn("unsupported linker extension flag: -z {s}", .{z_arg});
+                        fatal("unsupported linker extension flag: -z {s}", .{z_arg});
                     }
                 } else if (mem.eql(u8, arg, "--major-image-version")) {
                     i += 1;
@@ -2023,6 +2055,14 @@ fn buildOutputType(
                     // This option does not do anything.
                 } else if (mem.eql(u8, arg, "--export-all-symbols")) {
                     rdynamic = true;
+                } else if (mem.eql(u8, arg, "--color-diagnostics") or
+                    mem.eql(u8, arg, "--color-diagnostics=always"))
+                {
+                    color = .on;
+                } else if (mem.eql(u8, arg, "--no-color-diagnostics") or
+                    mem.eql(u8, arg, "--color-diagnostics=never"))
+                {
+                    color = .off;
                 } else if (mem.eql(u8, arg, "-s") or mem.eql(u8, arg, "--strip-all") or
                     mem.eql(u8, arg, "-S") or mem.eql(u8, arg, "--strip-debug"))
                 {
@@ -2186,7 +2226,7 @@ fn buildOutputType(
 
                     have_version = true;
                 } else {
-                    warn("unsupported linker arg: {s}", .{arg});
+                    fatal("unsupported linker arg: {s}", .{arg});
                 }
             }
 
@@ -3056,6 +3096,7 @@ fn buildOutputType(
         .version_script = version_script,
         .disable_c_depfile = disable_c_depfile,
         .soname = resolved_soname,
+        .linker_sort_section = linker_sort_section,
         .linker_gc_sections = linker_gc_sections,
         .linker_allow_shlib_undefined = linker_allow_shlib_undefined,
         .linker_bind_global_refs_locally = linker_bind_global_refs_locally,
@@ -3136,6 +3177,7 @@ fn buildOutputType(
         .headerpad_max_install_names = headerpad_max_install_names,
         .dead_strip_dylibs = dead_strip_dylibs,
         .reference_trace = reference_trace,
+        .error_tracing = error_tracing,
         .pdb_out_path = pdb_out_path,
     }) catch |err| switch (err) {
         error.LibCUnavailable => {
@@ -3607,7 +3649,7 @@ fn cmdTranslateC(comp: *Compilation, arena: Allocator, enable_cache: bool) !void
     defer if (enable_cache) man.deinit();
 
     man.hash.add(@as(u16, 0xb945)); // Random number to distinguish translate-c from compiling C objects
-    man.hashCSource(c_source_file) catch |err| {
+    Compilation.cache_helpers.hashCSource(&man, c_source_file) catch |err| {
         fatal("unable to process '{s}': {s}", .{ c_source_file.src_path, @errorName(err) });
     };
 
@@ -4523,7 +4565,7 @@ fn fmtPathDir(
 
         if (is_dir and (mem.eql(u8, entry.name, "zig-cache") or mem.eql(u8, entry.name, "zig-out"))) continue;
 
-        if (is_dir or entry.kind == .File and mem.endsWith(u8, entry.name, ".zig")) {
+        if (is_dir or entry.kind == .File and (mem.endsWith(u8, entry.name, ".zig") or mem.endsWith(u8, entry.name, ".zon"))) {
             const full_path = try fs.path.join(fmt.gpa, &[_][]const u8{ file_path, entry.name });
             defer fmt.gpa.free(full_path);
 
diff --git a/src/mingw.zig b/src/mingw.zig
index 06880743c6..4f94e26a98 100644
--- a/src/mingw.zig
+++ b/src/mingw.zig
@@ -8,7 +8,7 @@ const log = std.log.scoped(.mingw);
 const builtin = @import("builtin");
 const Compilation = @import("Compilation.zig");
 const build_options = @import("build_options");
-const Cache = @import("Cache.zig");
+const Cache = std.Build.Cache;
 
 pub const CRTFile = enum {
     crt2_o,
diff --git a/src/print_zir.zig b/src/print_zir.zig
index e5fc8815ed..8d97000582 100644
--- a/src/print_zir.zig
+++ b/src/print_zir.zig
@@ -332,7 +332,6 @@ const Writer = struct {
             .float_cast,
             .int_cast,
             .ptr_cast,
-            .qual_cast,
             .truncate,
             .align_cast,
             .div_exact,
@@ -507,6 +506,8 @@ const Writer = struct {
             .reify,
             .c_va_copy,
             .c_va_end,
+            .const_cast,
+            .volatile_cast,
             => {
                 const inst_data = self.code.extraData(Zir.Inst.UnNode, extended.operand).data;
                 const src = LazySrcLoc.nodeOffset(inst_data.node);
diff --git a/src/translate_c.zig b/src/translate_c.zig
index 17e8d5c82c..16a3c86757 100644
--- a/src/translate_c.zig
+++ b/src/translate_c.zig
@@ -1748,7 +1748,8 @@ fn transBinaryOperator(
         const lhs_expr = stmt.getLHS();
         const lhs_qt = getExprQualType(c, lhs_expr);
         const lhs_qt_translated = try transQualType(c, scope, lhs_qt, lhs_expr.getBeginLoc());
-        const elem_type = lhs_qt_translated.castTag(.c_pointer).?.data.elem_type;
+        const c_pointer = getContainer(c, lhs_qt_translated).?;
+        const elem_type = c_pointer.castTag(.c_pointer).?.data.elem_type;
         const sizeof = try Tag.sizeof.create(c.arena, elem_type);
 
         const bitcast = try Tag.bit_cast.create(c.arena, .{ .lhs = ptrdiff_type, .rhs = infixOpNode });