ld.lld: warning: Linking two modules of different target triples ... arm-unknown-linux-musleabihf vs armv6kz-unknown-linux-musleabihf

[andrewrk]

Extracted from #14647.

There are two problems here. One is #14908. The other looks like zig is failing to put the subarch into the llvm triple. This issue is to track the latter issue.

ld.lld: warning: Linking two modules of different target triples: '/home/andy/Downloads/zig/zig-cache/o/610cf441612621c1d4bea0844fb8daea/test.o' is 'arm-unknown-linux-musleabihf' whereas 'ld-temp.o' is 'armv6kz-unknown-linux-musleabihf'

zig/test/tests.zig

Lines 1019 to 1066 in b4d58e9

	pub fn addCAbiTests(b: *std.Build, skip_non_native: bool, skip_release: bool) *Step {
	const step = b.step("test-c-abi", "Run the C ABI tests");
	const optimize_modes: [2]OptimizeMode = .{ .Debug, .ReleaseFast };
	for (optimize_modes) |optimize_mode| {
	if (optimize_mode != .Debug and skip_release) continue;
	for (c_abi_targets) |c_abi_target| {
	if (skip_non_native and !c_abi_target.isNative()) continue;
	if (c_abi_target.isWindows() and c_abi_target.getCpuArch() == .aarch64) {
	// https://github.com/ziglang/zig/issues/14908
	continue;
	}
	const test_step = b.addTest(.{
	.root_source_file = .{ .path = "test/c_abi/main.zig" },
	.optimize = optimize_mode,
	.target = c_abi_target,
	});
	if (c_abi_target.abi != null and c_abi_target.abi.?.isMusl()) {
	// TODO NativeTargetInfo insists on dynamically linking musl
	// for some reason?
	test_step.target_info.dynamic_linker.max_byte = null;
	}
	test_step.linkLibC();
	test_step.addCSourceFile("test/c_abi/cfuncs.c", &.{"-std=c99"});
	// test-c-abi should test both with LTO on and with LTO off. Only
	// some combinations are passing currently:
	// https://github.com/ziglang/zig/issues/14908
	if (c_abi_target.isWindows()) {
	test_step.want_lto = false;
	}
	const triple_prefix = c_abi_target.zigTriple(b.allocator) catch @panic("OOM");
	test_step.setName(b.fmt("test-c-abi-{s}-{s} ", .{
	triple_prefix, @tagName(optimize_mode),
	}));
	const run = test_step.run();
	run.skip_foreign_checks = true;
	step.dependOn(&run.step);
	}
	}
	return step;
	}

[ikskuh]

We encountered the same problem when using MicroZig to build C files for arm

[cfillion]

Same issue here: building for ARM with some C sources. Disabling LTO works around it. An empty .c file + test.zig with only the entry point is enough to trigger the issue:

export fn _start() void {}

$ zig version
0.12.0
$ zig build-exe -target thumb-freestanding-eabihf test.zig empty.c -flto
LLD Link... warning(link): unexpected LLD stderr:
ld.lld: warning: Linking two modules of different target triples: 'test.o' is 'thumb-unknown-unknown-eabihf' whereas 'ld-temp.o' is 'thumbv6kz-unknown-unknown-eabihf'
$ zig build-exe -target thumb-freestanding-eabihf test.zig empty.c -fno-lto
# (success, no output)

zig build reports any linker stderr output as an error (error: warning(link): unexpected LLD stderr:), but since linking actually succeeded, it isn't re-done on subsequent invocations, so the error about LLD's warning only reappears the next time something else changes to trigger linking. (That seems like its own bug: errors should not vanish until solved or perhaps linker warnings should not be reported as an error in the first place?...)

[ikskuh]

The other looks like zig is failing to put the subarch into the llvm triple. This issue is to track the latter issue.

The problem still persists in 0.13 and i encountered it today when porting Ashet OS to Arm. I'll do a check if it still persists on the latest master state

[alexrp]

Fixed this a while back: #21574