Commit f2bf1390a29a9decaa5ca49d3ae720b360583b35 | zig

author	Jakub Konka <kubkon@jakubkonka.com> 2021-08-09 22:44:57+02:00
committer	Jakub Konka <kubkon@jakubkonka.com> 2021-08-10 08:13:07+02:00
log	f2bf1390a29a9decaa5ca49d3ae720b360583b35
tree	f040031c1ee692eef0b5d1e52fda6cfcdf265bbe
parent	2ccd023c6ae590b4ff311814ccf5ff508c7669ef

macho: fix linking of dylibs and frameworks

Previously, I have incorrectly assumed that with two-level namespace
we only need to link in dylibs/frameworks that actually export symbols
which are undefined in the linked image. Turns out, regardless of
whether we link with two-level namespace (default on macOS) or a
flat namespace (more common on other platforms), we always need to
put the dylibs/frameworks as specified by the user from the linker
line into the final linked image.

5 files changed, 54 insertions(+), 0 deletions(-)

src
- link
  - MachO.zig
  - MachO
    Dylib.zig
test
- standalone.zig
- standalone
  - link_frameworks
    build.zig
    main.c

src/link/MachO.zig+10

...	...	@@ -1013,7 +1013,12 @@ fn parseInputFiles(self: *MachO, files: []const []const u8, syslibroot: ?[]const
1013	1013	.syslibroot = syslibroot,
1014	1014	})) \|dylibs\| {
1015	1015	defer self.base.allocator.free(dylibs);
	1016	const dylib_id = @intCast(u16, self.dylibs.items.len);
1016	1017	try self.dylibs.appendSlice(self.base.allocator, dylibs);
	1018	// We always have to add the dylib that was on the linker line.
	1019	if (!self.referenced_dylibs.contains(dylib_id)) {
	1020	try self.referenced_dylibs.putNoClobber(self.base.allocator, dylib_id, {});
	1021	}
1017	1022	continue;
1018	1023	}
1019	1024
...	...	@@ -1028,7 +1033,12 @@ fn parseLibs(self: *MachO, libs: []const []const u8, syslibroot: ?[]const u8) !v
1028	1033	.syslibroot = syslibroot,
1029	1034	})) \|dylibs\| {
1030	1035	defer self.base.allocator.free(dylibs);
	1036	const dylib_id = @intCast(u16, self.dylibs.items.len);
1031	1037	try self.dylibs.appendSlice(self.base.allocator, dylibs);
	1038	// We always have to add the dylib that was on the linker line.
	1039	if (!self.referenced_dylibs.contains(dylib_id)) {
	1040	try self.referenced_dylibs.putNoClobber(self.base.allocator, dylib_id, {});
	1041	}
1032	1042	continue;
1033	1043	}
1034	1044

src/link/MachO/Dylib.zig+2

...	...	@@ -193,6 +193,8 @@ pub fn createAndParseFromPath(
193	193	defer dylibs.deinit();
194	194
195	195	try dylibs.append(dylib);
	196	// TODO this should not be performed if the user specifies `-flat_namespace` flag.
	197	// See ld64 manpages.
196	198	try dylib.parseDependentLibs(allocator, arch, &dylibs, opts.syslibroot);
197	199
198	200	return dylibs.toOwnedSlice();

test/standalone.zig+1

...	...	@@ -16,6 +16,7 @@ pub fn addCases(cases: *tests.StandaloneContext) void {
16	16	cases.addBuildFile("test/standalone/link_interdependent_static_c_libs/build.zig", .{});
17	17	cases.addBuildFile("test/standalone/link_static_lib_as_system_lib/build.zig", .{});
18	18	cases.addBuildFile("test/standalone/link_common_symbols/build.zig", .{});
	19	cases.addBuildFile("test/standalone/link_frameworks/build.zig", .{ .requires_macos_sdk = true });
19	20	cases.addBuildFile("test/standalone/issue_339/build.zig", .{});
20	21	cases.addBuildFile("test/standalone/issue_8550/build.zig", .{});
21	22	cases.addBuildFile("test/standalone/issue_794/build.zig", .{});

test/standalone/link_frameworks/build.zig created+34

...	...	@@ -0,0 +1,34 @@
	1	const std = @import("std");
	2	const Builder = std.build.Builder;
	3	const CrossTarget = std.zig.CrossTarget;
	4
	5	fn isRunnableTarget(t: CrossTarget) bool {
	6	// TODO I think we might be able to run this on Linux via Darling.
	7	// Add a check for that here, and return true if Darling is available.
	8	if (t.isNative() and t.getOsTag() == .macos)
	9	return true
	10	else
	11	return false;
	12	}
	13
	14	pub fn build(b: *Builder) void {
	15	const mode = b.standardReleaseOptions();
	16	const target = b.standardTargetOptions(.{});
	17
	18	const test_step = b.step("test", "Test the program");
	19
	20	const exe = b.addExecutable("test", null);
	21	b.default_step.dependOn(&exe.step);
	22	exe.addCSourceFile("main.c", &[0][]const u8{});
	23	exe.setBuildMode(mode);
	24	exe.setTarget(target);
	25	exe.linkLibC();
	26	// TODO when we figure out how to ship framework stubs for cross-compilation,
	27	// populate paths to the sysroot here.
	28	exe.linkFramework("Cocoa");
	29
	30	if (isRunnableTarget(target)) {
	31	const run_cmd = exe.run();
	32	test_step.dependOn(&run_cmd.step);
	33	}
	34	}

test/standalone/link_frameworks/main.c created+7

...	...	@@ -0,0 +1,7 @@
	1	#include <assert.h>
	2	#include <objc/runtime.h>
	3
	4	int main() {
	5	assert(objc_getClass("NSObject") > 0);
	6	assert(objc_getClass("NSApplication") > 0);
	7	}