std.dwarf: implement basic DWARF 5 parsing

DWARF 5 moves around some fields and adds a few new ones that can't be
parsed or ignored by our current DWARF 4 parser. This isn't a complete
implementation of DWARF 5, but this is enough to make stack traces
mostly work. Line numbers from C++ don't show up, but I know the info
is there. I think the answer is to iterate through .debug_line_str in
getLineNumberInfo, but I didn't want to fall into an even deeper rabbit
hole tonight.

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/std/debug.zig b/lib/std/debug.zig
index 3d06c16d57..9b02d418c5 100644
--- a/lib/std/debug.zig
+++ b/lib/std/debug.zig
@@ -797,6 +797,7 @@ fn readCoffDebugInfo(allocator: mem.Allocator, coff_file: File) !ModuleDebugInfo
             const debug_abbrev_data = di.coff.getSectionData(".debug_abbrev", allocator) catch null;
             const debug_str_data = di.coff.getSectionData(".debug_str", allocator) catch null;
             const debug_line_data = di.coff.getSectionData(".debug_line", allocator) catch null;
+            const debug_line_str_data = di.coff.getSectionData(".debug_line_str", allocator) catch null;
             const debug_ranges_data = di.coff.getSectionData(".debug_ranges", allocator) catch null;
 
             var dwarf = DW.DwarfInfo{
@@ -805,6 +806,7 @@ fn readCoffDebugInfo(allocator: mem.Allocator, coff_file: File) !ModuleDebugInfo
                 .debug_abbrev = debug_abbrev_data orelse return error.MissingDebugInfo,
                 .debug_str = debug_str_data orelse return error.MissingDebugInfo,
                 .debug_line = debug_line_data orelse return error.MissingDebugInfo,
+                .debug_line_str = debug_line_str_data,
                 .debug_ranges = debug_ranges_data,
             };
             try DW.openDwarfDebugInfo(&dwarf, allocator);
@@ -871,6 +873,7 @@ pub fn readElfDebugInfo(allocator: mem.Allocator, elf_file: File) !ModuleDebugIn
         var opt_debug_abbrev: ?[]const u8 = null;
         var opt_debug_str: ?[]const u8 = null;
         var opt_debug_line: ?[]const u8 = null;
+        var opt_debug_line_str: ?[]const u8 = null;
         var opt_debug_ranges: ?[]const u8 = null;
 
         for (shdrs) |*shdr| {
@@ -885,6 +888,8 @@ pub fn readElfDebugInfo(allocator: mem.Allocator, elf_file: File) !ModuleDebugIn
                 opt_debug_str = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
             } else if (mem.eql(u8, name, ".debug_line")) {
                 opt_debug_line = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
+            } else if (mem.eql(u8, name, ".debug_line_str")) {
+                opt_debug_line_str = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
             } else if (mem.eql(u8, name, ".debug_ranges")) {
                 opt_debug_ranges = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
             }
@@ -896,6 +901,7 @@ pub fn readElfDebugInfo(allocator: mem.Allocator, elf_file: File) !ModuleDebugIn
             .debug_abbrev = opt_debug_abbrev orelse return error.MissingDebugInfo,
             .debug_str = opt_debug_str orelse return error.MissingDebugInfo,
             .debug_line = opt_debug_line orelse return error.MissingDebugInfo,
+            .debug_line_str = opt_debug_line_str,
             .debug_ranges = opt_debug_ranges,
         };
 
@@ -1434,6 +1440,7 @@ pub const ModuleDebugInfo = switch (native_os) {
             var opt_debug_info: ?*const macho.section_64 = null;
             var opt_debug_abbrev: ?*const macho.section_64 = null;
             var opt_debug_str: ?*const macho.section_64 = null;
+            var opt_debug_line_str: ?*const macho.section_64 = null;
             var opt_debug_ranges: ?*const macho.section_64 = null;
 
             const sections = @ptrCast(
@@ -1456,6 +1463,8 @@ pub const ModuleDebugInfo = switch (native_os) {
                     opt_debug_abbrev = sect;
                 } else if (mem.eql(u8, name, "__debug_str")) {
                     opt_debug_str = sect;
+                } else if (mem.eql(u8, name, "__debug_line_str")) {
+                    opt_debug_line_str = sect;
                 } else if (mem.eql(u8, name, "__debug_ranges")) {
                     opt_debug_ranges = sect;
                 }
@@ -1476,6 +1485,10 @@ pub const ModuleDebugInfo = switch (native_os) {
                 .debug_abbrev = try chopSlice(mapped_mem, debug_abbrev.offset, debug_abbrev.size),
                 .debug_str = try chopSlice(mapped_mem, debug_str.offset, debug_str.size),
                 .debug_line = try chopSlice(mapped_mem, debug_line.offset, debug_line.size),
+                .debug_line_str = if (opt_debug_line_str) |debug_line_str|
+                    try chopSlice(mapped_mem, debug_line_str.offset, debug_line_str.size)
+                else
+                    null,
                 .debug_ranges = if (opt_debug_ranges) |debug_ranges|
                     try chopSlice(mapped_mem, debug_ranges.offset, debug_ranges.size)
                 else