Commit 32a069f909a34b22a2049dca39ef5a1965cba21b | zig

author	Matthew Lugg <mlugg@mlugg.co.uk> 2025-08-04 09:00:41+01:00
committer	Matthew Lugg <mlugg@mlugg.co.uk> 2025-08-04 09:47:56+01:00
log	32a069f909a34b22a2049dca39ef5a1965cba21b
tree	65dcaeee21ef8fd226be43e7441ad5f63612a91f
parent	dabae3f9dc868af92e7608d897befc39e5db5c33
signature	Commit is signed but in an unrecognized format.

cli: add `--debug-libc` to `zig build`

This option is similar to `--debug-target` in letting us override
details of the build runner target when debugging the build system.
While `--debug-target` lets us override the target query, this option
lets us override the libc installation. This option is only usable in a
compiler built with debug extensions.

I am using this to (try to) test the build runner targeting SerenityOS.

1 files changed, 18 insertions(+), 0 deletions(-)

src
- main.zig

src/main.zig+18

...	...	@@ -4891,6 +4891,7 @@ fn cmdBuild(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
4891	4891	var fetch_mode: Package.Fetch.JobQueue.Mode = .needed;
4892	4892	var system_pkg_dir_path: ?[]const u8 = null;
4893	4893	var debug_target: ?[]const u8 = null;
	4894	var debug_libc_paths_file: ?[]const u8 = null;
4894	4895
4895	4896	const argv_index_exe = child_argv.items.len;
4896	4897	_ = try child_argv.addOne();
...	...	@@ -5014,6 +5015,14 @@ fn cmdBuild(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
5014	5015	} else {
5015	5016	warn("Zig was compiled without debug extensions. --debug-target has no effect.", .{});
5016	5017	}
	5018	} else if (mem.eql(u8, arg, "--debug-libc")) {
	5019	if (i + 1 >= args.len) fatal("expected argument after '{s}'", .{arg});
	5020	i += 1;
	5021	if (build_options.enable_debug_extensions) {
	5022	debug_libc_paths_file = args[i];
	5023	} else {
	5024	warn("Zig was compiled without debug extensions. --debug-libc has no effect.", .{});
	5025	}
5017	5026	} else if (mem.eql(u8, arg, "--verbose-link")) {
5018	5027	verbose_link = true;
5019	5028	} else if (mem.eql(u8, arg, "--verbose-cc")) {
...	...	@@ -5101,6 +5110,14 @@ fn cmdBuild(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
5101	5110	.is_explicit_dynamic_linker = false,
5102	5111	};
5103	5112	};
	5113	// Likewise, `--debug-libc` allows overriding the libc installation.
	5114	const libc_installation: ?*const LibCInstallation = lci: {
	5115	const paths_file = debug_libc_paths_file orelse break :lci null;
	5116	if (!build_options.enable_debug_extensions) unreachable;
	5117	const lci = try arena.create(LibCInstallation);
	5118	lci.* = try .parse(arena, paths_file, &resolved_target.result);
	5119	break :lci lci;
	5120	};
5104	5121
5105	5122	process.raiseFileDescriptorLimit();
5106	5123
...	...	@@ -5365,6 +5382,7 @@ fn cmdBuild(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
5365	5382	}
5366	5383
5367	5384	const comp = Compilation.create(gpa, arena, .{
	5385	.libc_installation = libc_installation,
5368	5386	.dirs = dirs,
5369	5387	.root_name = "build",
5370	5388	.config = config,