Commit 9836f1b2f975cc484499847225eeb0ad54116942 | zig

author	Stephen Gutekanst <stephen@hexops.com> 2021-11-22 00:44:49-07:00
committer	GitHub <noreply@github.com> 2021-11-22 08:44:49+01:00
log	9836f1b2f975cc484499847225eeb0ad54116942
tree	bb8bf2340fc4045f571d323d56e13c48d0524ef5
parent	722c6b95671fcda0da1561205e487d169c046473
signature	Signed by PGP key 4AEE18F83AFDEB23

add support for compiling Objective-C++ code (#10096)

* add support for compiling Objective-C++ code

Prior to this change, calling `step.addCSourceFiles` with Obj-C++ file extensions
(`.mm`) would result in an error due to Zig not being aware of that extension.
Clang supports an `-ObjC++` compilation mode flag, but it was only possible to use
if you violated standards and renamed your `.mm` Obj-C++ files to `.m` (Obj-C) to
workaround Zig being unaware of the extension.

This change makes Zig aware of `.mm` files so they can be compiled, enabling compilation
of projects such as [Google's Dawn WebGPU](https://dawn.googlesource.com/dawn/) using
a `build.zig` file only.

Helps hexops/mach#21

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

* test/standalone: add ObjC++ compilation/linking test

Based on the existing objc example, just tweaked for ObjC++.

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

7 files changed, 90 insertions(+), 4 deletions(-)

src
- Compilation.zig
- main.zig
test
- standalone.zig
- standalone
  - objcpp
    Foo.h
    Foo.mm
    build.zig
    test.mm

src/Compilation.zig+14-2

...	...	@@ -3307,7 +3307,7 @@ pub fn addCCArgs(
3307	3307	try argv.appendSlice(&[_][]const u8{ "-target", llvm_triple });
3308	3308
3309	3309	switch (ext) {
3310		.c, .cpp, .m, .h => {
	3310	.c, .cpp, .m, .mm, .h => {
3311	3311	try argv.appendSlice(&[_][]const u8{
3312	3312	"-nostdinc",
3313	3313	"-fno-spell-checking",
...	...	@@ -3316,6 +3316,10 @@ pub fn addCCArgs(
3316	3316	try argv.append("-flto");
3317	3317	}
3318	3318
	3319	if (ext == .mm) {
	3320	try argv.append("-ObjC++");
	3321	}
	3322
3319	3323	// According to Rich Felker libc headers are supposed to go before C language headers.
3320	3324	// However as noted by @dimenus, appending libc headers before c_headers breaks intrinsics
3321	3325	// and other compiler specific items.
...	...	@@ -3599,6 +3603,7 @@ pub const FileExt = enum {
3599	3603	cpp,
3600	3604	h,
3601	3605	m,
	3606	mm,
3602	3607	ll,
3603	3608	bc,
3604	3609	assembly,
...	...	@@ -3610,7 +3615,7 @@ pub const FileExt = enum {
3610	3615
3611	3616	pub fn clangSupportsDepFile(ext: FileExt) bool {
3612	3617	return switch (ext) {
3613		.c, .cpp, .h, .m => true,
	3618	.c, .cpp, .h, .m, .mm => true,
3614	3619
3615	3620	.ll,
3616	3621	.bc,
...	...	@@ -3648,6 +3653,10 @@ pub fn hasObjCExt(filename: []const u8) bool {
3648	3653	return mem.endsWith(u8, filename, ".m");
3649	3654	}
3650	3655
	3656	pub fn hasObjCppExt(filename: []const u8) bool {
	3657	return mem.endsWith(u8, filename, ".mm");
	3658	}
	3659
3651	3660	pub fn hasAsmExt(filename: []const u8) bool {
3652	3661	return mem.endsWith(u8, filename, ".s") or mem.endsWith(u8, filename, ".S");
3653	3662	}
...	...	@@ -3686,6 +3695,8 @@ pub fn classifyFileExt(filename: []const u8) FileExt {
3686	3695	return .cpp;
3687	3696	} else if (hasObjCExt(filename)) {
3688	3697	return .m;
	3698	} else if (hasObjCppExt(filename)) {
	3699	return .mm;
3689	3700	} else if (mem.endsWith(u8, filename, ".ll")) {
3690	3701	return .ll;
3691	3702	} else if (mem.endsWith(u8, filename, ".bc")) {
...	...	@@ -3710,6 +3721,7 @@ pub fn classifyFileExt(filename: []const u8) FileExt {
3710	3721	test "classifyFileExt" {
3711	3722	try std.testing.expectEqual(FileExt.cpp, classifyFileExt("foo.cc"));
3712	3723	try std.testing.expectEqual(FileExt.m, classifyFileExt("foo.m"));
	3724	try std.testing.expectEqual(FileExt.mm, classifyFileExt("foo.mm"));
3713	3725	try std.testing.expectEqual(FileExt.unknown, classifyFileExt("foo.nim"));
3714	3726	try std.testing.expectEqual(FileExt.shared_library, classifyFileExt("foo.so"));
3715	3727	try std.testing.expectEqual(FileExt.shared_library, classifyFileExt("foo.so.1"));

src/main.zig+3-2

...	...	@@ -296,6 +296,7 @@ const usage_build_generic =
296	296	\\ .c C source code (requires LLVM extensions)
297	297	\\ .cxx .cc .C .cpp C++ source code (requires LLVM extensions)
298	298	\\ .m Objective-C source code (requires LLVM extensions)
	299	\\ .mm Objective-C++ source code (requires LLVM extensions)
299	300	\\ .bc LLVM IR Module (requires LLVM extensions)
300	301	\\
301	302	\\General Options:
...	...	@@ -1190,7 +1191,7 @@ fn buildOutputType(
1190	1191	.object, .static_library, .shared_library => {
1191	1192	try link_objects.append(arg);
1192	1193	},
1193		.assembly, .c, .cpp, .h, .ll, .bc, .m => {
	1194	.assembly, .c, .cpp, .h, .ll, .bc, .m, .mm => {
1194	1195	try c_source_files.append(.{
1195	1196	.src_path = arg,
1196	1197	.extra_flags = try arena.dupe([]const u8, extra_cflags.items),
...	...	@@ -1256,7 +1257,7 @@ fn buildOutputType(
1256	1257	.positional => {
1257	1258	const file_ext = Compilation.classifyFileExt(mem.spanZ(it.only_arg));
1258	1259	switch (file_ext) {
1259		.assembly, .c, .cpp, .ll, .bc, .h, .m => try c_source_files.append(.{ .src_path = it.only_arg }),
	1260	.assembly, .c, .cpp, .ll, .bc, .h, .m, .mm => try c_source_files.append(.{ .src_path = it.only_arg }),
1260	1261	.unknown, .shared_library, .object, .static_library => {
1261	1262	try link_objects.append(it.only_arg);
1262	1263	},

test/standalone.zig+5

...	...	@@ -69,6 +69,11 @@ pub fn addCases(cases: *tests.StandaloneContext) void {
69	69	.build_modes = true,
70	70	.requires_macos_sdk = true,
71	71	});
	72	// Try to build and run an Objective-C++ executable.
	73	cases.addBuildFile("test/standalone/objcpp/build.zig", .{
	74	.build_modes = true,
	75	.requires_macos_sdk = true,
	76	});
72	77
73	78	// Ensure the development tools are buildable.
74	79	cases.add("tools/gen_spirv_spec.zig");

test/standalone/objcpp/Foo.h created+7

...	...	@@ -0,0 +1,7 @@
	1	#import <Foundation/Foundation.h>
	2
	3	@interface Foo : NSObject
	4
	5	- (NSString *)name;
	6
	7	@end

test/standalone/objcpp/Foo.mm created+11

...	...	@@ -0,0 +1,11 @@
	1	#import "Foo.h"
	2
	3	@implementation Foo
	4
	5	- (NSString *)name
	6	{
	7	NSString *str = [[NSString alloc] initWithFormat:@"Zig"];
	8	return str;
	9	}
	10
	11	@end

test/standalone/objcpp/build.zig created+36

...	...	@@ -0,0 +1,36 @@
	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.addIncludeDir(".");
	23	exe.addCSourceFile("Foo.mm", &[0][]const u8{});
	24	exe.addCSourceFile("test.mm", &[0][]const u8{});
	25	exe.setBuildMode(mode);
	26	exe.setTarget(target);
	27	exe.linkLibCpp();
	28	// TODO when we figure out how to ship framework stubs for cross-compilation,
	29	// populate paths to the sysroot here.
	30	exe.linkFramework("Foundation");
	31
	32	if (isRunnableTarget(target)) {
	33	const run_cmd = exe.run();
	34	test_step.dependOn(&run_cmd.step);
	35	}
	36	}

test/standalone/objcpp/test.mm created+14

...	...	@@ -0,0 +1,14 @@
	1	#import "Foo.h"
	2	#import <assert.h>
	3	#include <iostream>
	4
	5	int main(int argc, char *argv[])
	6	{
	7	@autoreleasepool {
	8	Foo *foo = [[Foo alloc] init];
	9	NSString *result = [foo name];
	10	std::cout << "Hello from C++ and " << [result UTF8String];
	11	assert([result isEqualToString:@"Zig"]);
	12	return 0;
	13	}
	14	}