x86_64: linking libc panics with TODO unhandled compression scheme #24954
Description
Zig Version
0.16.0-dev.9+8248597a2
Steps to Reproduce and Observed Behavior
me@gekai ~> uname -rom
6.15.6-321.current x86_64 GNU/Linuxme@gekai ~> cat /etc/os-release
NAME="Solus"
VERSION="4.7"
ID="solus"
VERSION_CODENAME=endurance
VERSION_ID="4.7"
PRETTY_NAME="Solus 4.7 Endurance"// main.zig
pub fn main() void {}// build.zig
const std = @import("std");
pub fn build(b: *std.Build) void {
const target = b.standardTargetOptions(.{});
const optimize = b.standardOptimizeOption(.{});
const exe = b.addExecutable(.{
.name = "test",
.root_module = b.createModule(.{
.root_source_file = b.path("src/main.zig"),
.target = target,
.optimize = optimize,
.link_libc = true,
}),
// .use_llvm = true, // works when using LLVM
});
b.installArtifact(exe);
}me@gekai ~/N/d/p/z/test> zig build
install
└─ install test
└─ compile exe test Debug native failure
error: thread 165492 panic: TODO unhandled compression scheme
Unable to dump stack trace: debug info strippedExpected Behavior
Build succeeds without any issues.
Notes:
- using LLVM instead of the x86_64 backend works fine
- in an attempt to debug this, I went down the rabbit hole of compiling LLVM and Zig from scratch because Solus has an older version of the LLVM toolchain, but that, funnily enough, also failed at the linking step. Interestingly, this didn't happen when using CachyOS (?)
- I discovered that
chdr.ch_typehere equalsZSTDin my case - applying the following diff (adapted from the ZLIB one) resolves the issue
--- a/src/link/Elf/Object.zig
+++ b/src/link/Elf/Object.zig
@@ -1207,6 +1207,17 @@ pub fn codeDecompressAlloc(self: *Object, elf_file: *Elf, atom_index: Atom.Index
_ = try zlib_stream.reader.streamRemaining(&aw.writer);
return aw.toOwnedSlice();
},
+ .ZSTD => {
+ var reader: std.Io.Reader = .fixed(data[@sizeOf(elf.Elf64_Chdr)..]);
+ var stream: std.compress.zstd.Decompress = .init(&reader, &.{}, .{});
+ const size = std.math.cast(usize, chdr.ch_size) orelse return error.Overflow;
+ var aw: std.Io.Writer.Allocating = .init(gpa);
+ defer aw.deinit();
+ try aw.ensureUnusedCapacity(size);
+ _ = try stream.reader.streamRemaining(&aw.writer);
+
+ return aw.toOwnedSlice();
+ },
else => @panic("TODO unhandled compression scheme"),
}
}