Commit 539bdfc46ff75a4a4febb97a7700ade393c1cb22 | zig

author	Theo Fabi <fabi.theo@gmail.com> 2026-07-24 12:31:28-04:00
committer	Alex Rønne Petersen <alex@alexrp.com> 2026-08-02 14:18:11+02:00
log	539bdfc46ff75a4a4febb97a7700ade393c1cb22
tree	b981f2dd45e86355043c53cf9642e5be4bcfa045
parent	1b7b856a810708ecfc8f78298cdd0a76315e8578

debug.MachOFile: handle truncated dwarf section names

Some dwarf section names like __debug_str_offsets don't fit in a Mach-O
sectname buffer, so their actual name in Mach-O binaries is truncated.

When searching for sections to load an object file's debug info, we now
compare the section name with the truncated name. Before, the full name
was checked, so we would unconditionally skip __debug_str_offsets dwarf
sections.

1 files changed, 5 insertions(+), 2 deletions(-)

lib
- std
  - debug
    MachOFile.zig

lib/std/debug/MachOFile.zig+5-2

 @@ -504,8 +504,11 @@ fn loadOFile(gpa: Allocator, io: Io, o_file_name: []const u8) !OFile {
         if (!std.mem.eql(u8, "__DWARF", sect.segName())) continue;
-        const section_index: usize = inline for (@typeInfo(Dwarf.Section.Id).@"enum".field_names, 0..) |section_name, i| {
+        const section_index: usize = inline for (@typeInfo(Dwarf.Section.Id).@"enum".field_names, 0..) |field_name, i| {
-            if (mem.eql(u8, "__" ++ section_name, sect.sectName())) break i;
+            const section_name_long = "__" ++ field_name;
+            // Some dwarf section names don't fit in the `sectname` buffer, so they are truncated.
+            const section_name_trunc = section_name_long[0..@min(section_name_long.len, sect.sectname.len)];
+            if (mem.eql(u8, section_name_trunc, sect.sectName())) break i;
         } else continue;
         if (mapped_ofile.len < sect.offset + sect.size) return error.InvalidMachO;