Meg's Mirrors

zig

1	pub const Atom = @import("MachO/Atom.zig");
2	pub const DebugSymbols = @import("MachO/DebugSymbols.zig");
3	pub const Relocation = @import("MachO/Relocation.zig");
4
5	base: link.File,
6
7	rpath_list: []const []const u8,
8
9	/// Debug symbols bundle (or dSym).
10	d_sym: ?DebugSymbols = null,
11
12	/// A list of all input files.
13	/// Index of each input file also encodes the priority or precedence of one input file
14	/// over another.
15	files: std.MultiArrayList(File.Entry) = .{},
16	/// Long-lived list of all file descriptors.
17	/// We store them globally rather than per actual File so that we can re-use
18	/// one file handle per every object file within an archive.
19	file_handles: std.ArrayList(File.Handle) = .empty,
20	zig_object: ?File.Index = null,
21	internal_object: ?File.Index = null,
22	objects: std.ArrayList(File.Index) = .empty,
23	dylibs: std.ArrayList(File.Index) = .empty,
24
25	segments: std.ArrayList(macho.segment_command_64) = .empty,
26	sections: std.MultiArrayList(Section) = .{},
27	/// Populated by `allocateSections`.
28	header_size: ?u32 = null,
29
30	resolver: SymbolResolver = .{},
31	/// This table will be populated after `scanRelocs` has run.
32	/// Key is symbol index.
33	undefs: std.array_hash_map.Auto(SymbolResolver.Index, UndefRefs) = .empty,
34	undefs_mutex: std.Io.Mutex = .init,
35	dupes: std.array_hash_map.Auto(SymbolResolver.Index, std.ArrayList(File.Index)) = .empty,
36	dupes_mutex: std.Io.Mutex = .init,
37
38	dyld_info_cmd: macho.dyld_info_command = .{},
39	symtab_cmd: macho.symtab_command = .{},
40	dysymtab_cmd: macho.dysymtab_command = .{},
41	function_starts_cmd: macho.linkedit_data_command = .{ .cmd = .FUNCTION_STARTS },
42	data_in_code_cmd: macho.linkedit_data_command = .{ .cmd = .DATA_IN_CODE },
43	uuid_cmd: macho.uuid_command = .{ .uuid = @splat(0) },
44	codesig_cmd: macho.linkedit_data_command = .{ .cmd = .CODE_SIGNATURE },
45
46	pagezero_seg_index: ?u8 = null,
47	text_seg_index: ?u8 = null,
48	linkedit_seg_index: ?u8 = null,
49	text_sect_index: ?u8 = null,
50	data_sect_index: ?u8 = null,
51	got_sect_index: ?u8 = null,
52	stubs_sect_index: ?u8 = null,
53	stubs_helper_sect_index: ?u8 = null,
54	la_symbol_ptr_sect_index: ?u8 = null,
55	tlv_ptr_sect_index: ?u8 = null,
56	eh_frame_sect_index: ?u8 = null,
57	unwind_info_sect_index: ?u8 = null,
58	objc_stubs_sect_index: ?u8 = null,
59
60	thunks: std.ArrayList(Thunk) = .empty,
61
62	/// Output synthetic sections
63	symtab: std.ArrayList(macho.nlist_64) = .empty,
64	strtab: std.ArrayList(u8) = .empty,
65	indsymtab: Indsymtab = .{},
66	got: GotSection = .{},
67	stubs: StubsSection = .{},
68	stubs_helper: StubsHelperSection = .{},
69	objc_stubs: ObjcStubsSection = .{},
70	la_symbol_ptr: LaSymbolPtrSection = .{},
71	tlv_ptr: TlvPtrSection = .{},
72	rebase_section: Rebase = .{},
73	bind_section: Bind = .{},
74	weak_bind_section: WeakBind = .{},
75	lazy_bind_section: LazyBind = .{},
76	export_trie: ExportTrie = .{},
77	unwind_info: UnwindInfo = .{},
78	data_in_code: DataInCode = .{},
79
80	/// Tracked loadable segments during incremental linking.
81	zig_text_seg_index: ?u8 = null,
82	zig_const_seg_index: ?u8 = null,
83	zig_data_seg_index: ?u8 = null,
84	zig_bss_seg_index: ?u8 = null,
85
86	/// Tracked section headers with incremental updates to Zig object.
87	zig_text_sect_index: ?u8 = null,
88	zig_const_sect_index: ?u8 = null,
89	zig_data_sect_index: ?u8 = null,
90	zig_bss_sect_index: ?u8 = null,
91
92	/// Tracked DWARF section headers that apply only when we emit relocatable.
93	/// For executable and loadable images, DWARF is tracked directly by dSYM bundle object.
94	debug_info_sect_index: ?u8 = null,
95	debug_abbrev_sect_index: ?u8 = null,
96	debug_str_sect_index: ?u8 = null,
97	debug_aranges_sect_index: ?u8 = null,
98	debug_line_sect_index: ?u8 = null,
99	debug_line_str_sect_index: ?u8 = null,
100	debug_loclists_sect_index: ?u8 = null,
101	debug_rnglists_sect_index: ?u8 = null,
102
103	has_tlv: AtomicBool = AtomicBool.init(false),
104	binds_to_weak: AtomicBool = AtomicBool.init(false),
105	weak_defines: AtomicBool = AtomicBool.init(false),
106
107	/// Options
108	/// SDK layout
109	sdk_layout: ?SdkLayout,
110	/// Size of the __PAGEZERO segment.
111	pagezero_size: ?u64,
112	/// Minimum space for future expansion of the load commands.
113	headerpad_size: ?u32,
114	/// Set enough space as if all paths were MATPATHLEN.
115	headerpad_max_install_names: bool,
116	/// Remove dylibs that are unreachable by the entry point or exported symbols.
117	dead_strip_dylibs: bool,
118	/// Treatment of undefined symbols
119	undefined_treatment: UndefinedTreatment,
120	/// TODO: delete this, libraries need to be resolved by the frontend instead
121	lib_directories: []const Directory,
122	/// Resolved list of framework search directories
123	framework_dirs: []const []const u8,
124	/// List of input frameworks
125	frameworks: []const Framework,
126	/// Install name for the dylib.
127	/// TODO: unify with soname
128	install_name: ?[]const u8,
129	/// Path to entitlements file.
130	entitlements: ?Path,
131	compatibility_version: ?std.SemanticVersion,
132	/// Entry name
133	entry_name: ?[]const u8,
134	platform: Platform,
135	sdk_version: ?std.SemanticVersion,
136	/// When set to true, the linker will hoist all dylibs including system dependent dylibs.
137	no_implicit_dylibs: bool = false,
138	/// Whether the linker should parse and always force load objects containing ObjC in archives.
139	// TODO: in Zig we currently take -ObjC as always on
140	force_load_objc: bool = true,
141	/// Whether local symbols should be discarded from the symbol table.
142	discard_local_symbols: bool = false,
143
144	/// Hot-code swapping state.
145	hot_state: if (is_hot_update_compatible) HotUpdateState else struct {} = .{},
146
147	/// When adding a new field, remember to update `hashAddFrameworks`.
148	pub const Framework = struct {
149	needed: bool = false,
150	weak: bool = false,
151	path: Path,
152	};
153
154	pub fn hashAddFrameworks(man: *Cache.Manifest, hm: []const Framework) !void {
155	for (hm) |value| {
156	man.hash.add(value.needed);
157	man.hash.add(value.weak);
158	_ = try man.addFilePath(value.path, null);
159	}
160	}
161
162	pub fn createEmpty(
163	arena: Allocator,
164	comp: *Compilation,
165	emit: Path,
166	options: link.File.OpenOptions,
167	) !*MachO {
168	const target = &comp.root_mod.resolved_target.result;
169	assert(target.ofmt == .macho);
170
171	const gpa = comp.gpa;
172	const use_llvm = comp.config.use_llvm;
173	const opt_zcu = comp.zcu;
174	const optimize_mode = comp.root_mod.optimize_mode;
175	const output_mode = comp.config.output_mode;
176	const link_mode = comp.config.link_mode;
177
178	const allow_shlib_undefined = options.allow_shlib_undefined orelse false;
179
180	const self = try arena.create(MachO);
181	self.* = .{
182	.base = .{
183	.tag = .macho,
184	.comp = comp,
185	.emit = emit,
186	.gc_sections = options.gc_sections orelse (optimize_mode != .debug),
187	.print_gc_sections = options.print_gc_sections,
188	.stack_size = options.stack_size orelse 16777216,
189	.allow_shlib_undefined = allow_shlib_undefined,
190	.file = null,
191	.build_id = options.build_id,
192	},
193	.rpath_list = options.rpath_list,
194	.pagezero_size = options.pagezero_size,
195	.headerpad_size = options.headerpad_size,
196	.headerpad_max_install_names = options.headerpad_max_install_names,
197	.dead_strip_dylibs = options.dead_strip_dylibs,
198	.sdk_layout = options.darwin_sdk_layout,
199	.frameworks = options.frameworks,
200	.install_name = options.install_name,
201	.entitlements = options.entitlements,
202	.compatibility_version = options.compatibility_version,
203	.entry_name = switch (options.entry) {
204	.disabled => null,
205	.default => if (output_mode != .Exe) null else default_entry_symbol_name,
206	.enabled => default_entry_symbol_name,
207	.named => |name| name,
208	},
209	.platform = Platform.fromTarget(target),
210	.sdk_version = if (options.darwin_sdk_layout) |layout| inferSdkVersion(comp, layout) else null,
211	.undefined_treatment = if (allow_shlib_undefined) .dynamic_lookup else .@"error",
212	// TODO delete this, directories must instead be resolved by the frontend
213	.lib_directories = options.lib_directories,
214	.framework_dirs = options.framework_dirs,
215	.force_load_objc = options.force_load_objc,
216	.discard_local_symbols = options.discard_local_symbols,
217	};
218	errdefer self.base.destroy();
219
220	const io = comp.io;
221
222	self.base.file = try emit.root_dir.handle.createFile(io, emit.sub_path, .{
223	.truncate = true,
224	.read = true,
225	.permissions = link.File.determinePermissions(output_mode, link_mode),
226	});
227
228	// Append null file
229	try self.files.append(gpa, .null);
230	// Append empty string to string tables
231	try self.strtab.append(gpa, 0);
232
233	if (opt_zcu) |zcu| {
234	if (!use_llvm) {
235	const index: File.Index = @intCast(try self.files.addOne(gpa));
236	self.files.set(index, .{ .zig_object = .{
237	.index = index,
238	.basename = try std.fmt.allocPrint(arena, "{s}.o", .{
239	fs.path.stem(zcu.main_mod.root_src_path),
240	}),
241	} });
242	self.zig_object = index;
243	const zo = self.getZigObject().?;
244	try zo.init(self);
245
246	try self.initMetadata(.{
247	.emit = emit,
248	.zo = zo,
249	.symbol_count_hint = options.symbol_count_hint,
250	.program_code_size_hint = options.program_code_size_hint,
251	});
252	}
253	}
254
255	return self;
256	}
257
258	pub fn open(
259	arena: Allocator,
260	comp: *Compilation,
261	emit: Path,
262	options: link.File.OpenOptions,
263	) !*MachO {
264	// TODO: restore saved linker state, don't truncate the file, and
265	// participate in incremental compilation.
266	return createEmpty(arena, comp, emit, options);
267	}
268
269	pub fn deinit(self: *MachO) void {
270	const comp = self.base.comp;
271	const gpa = comp.gpa;
272	const io = comp.io;
273
274	if (self.d_sym) |*d_sym| {
275	d_sym.deinit();
276	}
277
278	for (self.file_handles.items) |handle| {
279	handle.close(io);
280	}
281	self.file_handles.deinit(gpa);
282
283	for (self.files.items(.tags), self.files.items(.data)) |tag, *data| switch (tag) {
284	.null => {},
285	.zig_object => data.zig_object.deinit(gpa),
286	.internal => data.internal.deinit(gpa),
287	.object => data.object.deinit(gpa),
288	.dylib => data.dylib.deinit(gpa),
289	};
290	self.files.deinit(gpa);
291	self.objects.deinit(gpa);
292	self.dylibs.deinit(gpa);
293
294	self.segments.deinit(gpa);
295	for (
296	self.sections.items(.atoms),
297	self.sections.items(.out),
298	self.sections.items(.thunks),
299	self.sections.items(.relocs),
300	) |*atoms, *out, *thnks, *relocs| {
301	atoms.deinit(gpa);
302	out.deinit(gpa);
303	thnks.deinit(gpa);
304	relocs.deinit(gpa);
305	}
306	self.sections.deinit(gpa);
307
308	self.resolver.deinit(gpa);
309
310	for (self.undefs.values()) |*val| {
311	val.deinit(gpa);
312	}
313	self.undefs.deinit(gpa);
314	for (self.dupes.values()) |*val| {
315	val.deinit(gpa);
316	}
317	self.dupes.deinit(gpa);
318
319	self.symtab.deinit(gpa);
320	self.strtab.deinit(gpa);
321	self.got.deinit(gpa);
322	self.stubs.deinit(gpa);
323	self.objc_stubs.deinit(gpa);
324	self.tlv_ptr.deinit(gpa);
325	self.rebase_section.deinit(gpa);
326	self.bind_section.deinit(gpa);
327	self.weak_bind_section.deinit(gpa);
328	self.lazy_bind_section.deinit(gpa);
329	self.export_trie.deinit(gpa);
330	self.unwind_info.deinit(gpa);
331	self.data_in_code.deinit(gpa);
332
333	for (self.thunks.items) |*thunk| thunk.deinit(gpa);
334	self.thunks.deinit(gpa);
335	}
336
337	pub fn flush(
338	self: *MachO,
339	arena: Allocator,
340	tid: Zcu.PerThread.Id,
341	prog_node: std.Progress.Node,
342	) link.Error!void {
343	const tracy = trace(@src());
344	defer tracy.end();
345
346	const comp = self.base.comp;
347	const gpa = comp.gpa;
348	const io = comp.io;
349	const diags = &comp.link_diags;
350
351	const sub_prog_node = prog_node.start("MachO Flush", 0);
352	defer sub_prog_node.end();
353
354	const zcu_obj_path: ?Path = p: {
355	const zcu = comp.zcu orelse break :p null;
356	const llvm_object = zcu.llvm_object orelse break :p null;
357	break :p try comp.resolveEmitPathFlush(arena, .temp, llvm_object.out_bin_basename);
358	};
359
360	// --verbose-link
361	if (comp.verbose_link) try self.dumpArgv(comp);
362
363	if (self.getZigObject()) |zo| try zo.flush(self, tid);
364	if (self.base.isStaticLib()) return relocatable.flushStaticLib(self, comp, zcu_obj_path);
365	if (self.base.isObject()) return relocatable.flushObject(self, comp, zcu_obj_path);
366
367	var positionals = std.array_list.Managed(link.Input).init(gpa);
368	defer positionals.deinit();
369
370	try positionals.ensureUnusedCapacity(comp.link_inputs.len);
371
372	for (comp.link_inputs) |link_input| switch (link_input) {
373	.dso => continue, // handled below
374	.object, .archive => positionals.appendAssumeCapacity(link_input),
375	.dso_exact => @panic("TODO"),
376	.res => unreachable,
377	};
378
379	// This is a set of object files emitted by clang in a single `build-exe` invocation.
380	// For instance, the implicit `a.o` as compiled by `zig build-exe a.c` will end up
381	// in this set.
382	try positionals.ensureUnusedCapacity(comp.c_objects.items.len);
383	for (comp.c_objects.items) |c_object| {
384	positionals.appendAssumeCapacity(try link.openObjectInput(io, diags, c_object.status.success.object_path));
385	}
386
387	if (zcu_obj_path) |path| try positionals.append(try link.openObjectInput(io, diags, path));
388
389	if (comp.config.any_sanitize_thread) {
390	try positionals.append(try link.openObjectInput(io, diags, comp.tsan_lib.?.full_object_path));
391	}
392
393	if (comp.config.any_fuzz) {
394	try positionals.append(try link.openArchiveInput(io, diags, comp.fuzzer_lib.?.full_object_path, false, false));
395	}
396
397	if (comp.ubsan_rt_lib) |crt_file| {
398	const path = crt_file.full_object_path;
399	self.classifyInputFile(try link.openArchiveInput(io, diags, path, false, false)) catch |err|
400	diags.addParseError(path, "failed to parse archive: {s}", .{@errorName(err)});
401	} else if (comp.ubsan_rt_obj) |crt_file| {
402	const path = crt_file.full_object_path;
403	self.classifyInputFile(try link.openObjectInput(io, diags, path)) catch |err|
404	diags.addParseError(path, "failed to parse archive: {s}", .{@errorName(err)});
405	}
406
407	for (positionals.items) |link_input| {
408	self.classifyInputFile(link_input) catch |err|
409	diags.addParseError(link_input.path().?, "failed to read input file: {s}", .{@errorName(err)});
410	}
411
412	var system_libs = std.array_list.Managed(SystemLib).init(gpa);
413	defer system_libs.deinit();
414
415	// frameworks
416	try system_libs.ensureUnusedCapacity(self.frameworks.len);
417	for (self.frameworks) |info| {
418	system_libs.appendAssumeCapacity(.{
419	.needed = info.needed,
420	.weak = info.weak,
421	.path = info.path,
422	});
423	}
424
425	// libc++ dep
426	if (comp.config.link_libcpp) {
427	try system_libs.ensureUnusedCapacity(2);
428	system_libs.appendAssumeCapacity(.{ .path = comp.libcxxabi_static_lib.?.full_object_path });
429	system_libs.appendAssumeCapacity(.{ .path = comp.libcxx_static_lib.?.full_object_path });
430	}
431
432	const is_exe_or_dyn_lib = comp.config.output_mode == .Exe or
433	(comp.config.output_mode == .Lib and comp.config.link_mode == .dynamic);
434
435	if (comp.config.link_libc and is_exe_or_dyn_lib) {
436	if (comp.zigc_static_lib) |zigc| {
437	const path = zigc.full_object_path;
438	self.classifyInputFile(try link.openArchiveInput(io, diags, path, false, false)) catch |err|
439	diags.addParseError(path, "failed to parse archive: {s}", .{@errorName(err)});
440	}
441	}
442
443	// libc/libSystem dep
444	self.resolveLibSystem(arena, comp, &system_libs) catch |err| switch (err) {
445	error.MissingLibSystem => {}, // already reported
446	else => |e| return diags.fail("failed to resolve libSystem: {s}", .{@errorName(e)}),
447	};
448
449	for (comp.link_inputs) |link_input| switch (link_input) {
450	.object, .archive, .dso_exact => continue,
451	.res => unreachable,
452	.dso => {
453	self.classifyInputFile(link_input) catch |err|
454	diags.addParseError(link_input.path().?, "failed to parse input file: {s}", .{@errorName(err)});
455	},
456	};
457
458	for (system_libs.items) |lib| {
459	switch (Compilation.classifyFileExt(lib.path.sub_path)) {
460	.shared_library => {
461	const dso_input = try link.openDsoInput(io, diags, lib.path, lib.needed, lib.weak, lib.reexport);
462	self.classifyInputFile(dso_input) catch |err|
463	diags.addParseError(lib.path, "failed to parse input file: {s}", .{@errorName(err)});
464	},
465	.static_library => {
466	const archive_input = try link.openArchiveInput(io, diags, lib.path, lib.must_link, lib.hidden);
467	self.classifyInputFile(archive_input) catch |err|
468	diags.addParseError(lib.path, "failed to parse input file: {s}", .{@errorName(err)});
469	},
470	else => unreachable,
471	}
472	}
473
474	// Finally, link against compiler_rt.
475	if (comp.compiler_rt_lib) |crt_file| {
476	const path = crt_file.full_object_path;
477	self.classifyInputFile(try link.openArchiveInput(io, diags, path, false, false)) catch |err|
478	diags.addParseError(path, "failed to parse archive: {s}", .{@errorName(err)});
479	} else if (comp.compiler_rt_obj) |crt_file| {
480	const path = crt_file.full_object_path;
481	self.classifyInputFile(try link.openObjectInput(io, diags, path)) catch |err|
482	diags.addParseError(path, "failed to parse archive: {s}", .{@errorName(err)});
483	}
484
485	try self.parseInputFiles();
486	self.parseDependentDylibs() catch |err| {
487	switch (err) {
488	error.MissingLibraryDependencies => {},
489	else => |e| return diags.fail("failed to parse dependent libraries: {s}", .{@errorName(e)}),
490	}
491	};
492
493	if (diags.hasErrors()) return error.AlreadyReported;
494
495	{
496	const index = @as(File.Index, @intCast(try self.files.addOne(gpa)));
497	self.files.set(index, .{ .internal = .{ .index = index } });
498	self.internal_object = index;
499	const object = self.getInternalObject().?;
500	try object.init(gpa);
501	try object.initSymbols(self);
502	}
503
504	try self.resolveSymbols();
505	try self.convertTentativeDefsAndResolveSpecialSymbols();
506	self.dedupLiterals() catch |err| switch (err) {
507	error.AlreadyReported => |e| return e,
508	else => |e| return diags.fail("failed to deduplicate literals: {s}", .{@errorName(e)}),
509	};
510
511	if (self.base.gc_sections) {
512	try dead_strip.gcAtoms(self);
513	}
514
515	self.checkDuplicates() catch |err| switch (err) {
516	error.HasDuplicates => return error.AlreadyReported,
517	else => |e| return diags.fail("failed to check for duplicate symbol definitions: {s}", .{@errorName(e)}),
518	};
519
520	self.markImportsAndExports();
521	self.deadStripDylibs();
522
523	for (self.dylibs.items, 1..) |index, ord| {
524	const dylib = self.getFile(index).?.dylib;
525	dylib.ordinal = @intCast(ord);
526	}
527
528	self.claimUnresolved();
529
530	self.scanRelocs() catch |err| switch (err) {
531	error.HasUndefinedSymbols => return error.AlreadyReported,
532	else => |e| return diags.fail("failed to scan relocations: {s}", .{@errorName(e)}),
533	};
534
535	try self.initOutputSections();
536	try self.initSyntheticSections();
537	try self.sortSections();
538	try self.addAtomsToSections();
539	try self.calcSectionSizes();
540
541	try self.generateUnwindInfo();
542
543	try self.initSegments();
544	self.allocateSections() catch |err| switch (err) {
545	error.AlreadyReported => |e| return e,
546	else => |e| return diags.fail("failed to allocate sections: {s}", .{@errorName(e)}),
547	};
548	self.allocateSegments();
549	self.allocateSyntheticSymbols();
550
551	if (build_options.enable_logging) {
552	state_log.debug("{f}", .{self.dumpState()});
553	}
554
555	// Beyond this point, everything has been allocated a virtual address and we can resolve
556	// the relocations, and commit objects to file.
557	try self.resizeSections();
558
559	if (self.getZigObject()) |zo| {
560	zo.resolveRelocs(self) catch |err| switch (err) {
561	error.ResolveFailed => return error.AlreadyReported,
562	else => |e| return e,
563	};
564	}
565	try self.writeSectionsAndUpdateLinkeditSizes();
566
567	try self.writeSectionsToFile();
568	try self.allocateLinkeditSegment();
569	self.writeLinkeditSectionsToFile() catch |err| switch (err) {
570	error.OutOfMemory, error.AlreadyReported => |e| return e,
571	else => |e| return diags.fail("failed to write linkedit sections to file: {t}", .{e}),
572	};
573
574	var codesig: ?CodeSignature = if (self.requiresCodeSig()) blk: {
575	// Preallocate space for the code signature.
576	// We need to do this at this stage so that we have the load commands with proper values
577	// written out to the file.
578	// The most important here is to have the correct vm and filesize of the __LINKEDIT segment
579	// where the code signature goes into.
580	var codesig = CodeSignature.init(self.getPageSize());
581	codesig.code_directory.ident = fs.path.basename(self.base.emit.sub_path);
582	if (self.entitlements) |path| codesig.addEntitlements(gpa, io, path) catch |err|
583	return diags.fail("failed to add entitlements from {f}: {t}", .{ path, err });
584	try self.writeCodeSignaturePadding(&codesig);
585	break :blk codesig;
586	} else null;
587	defer if (codesig) |*csig| csig.deinit(gpa);
588
589	self.getLinkeditSegment().vmsize = mem.alignForward(
590	u64,
591	self.getLinkeditSegment().filesize,
592	self.getPageSize(),
593	);
594
595	const ncmds, const sizeofcmds, const uuid_cmd_offset = self.writeLoadCommands() catch |err| switch (err) {
596	error.WriteFailed => unreachable,
597	error.OutOfMemory, error.AlreadyReported => |e| return e,
598	};
599	try self.writeHeader(ncmds, sizeofcmds);
600	self.writeUuid(uuid_cmd_offset, self.requiresCodeSig()) catch |err| switch (err) {
601	error.OutOfMemory, error.AlreadyReported => |e| return e,
602	else => |e| return diags.fail("failed to calculate and write uuid: {s}", .{@errorName(e)}),
603	};
604	if (self.getDebugSymbols()) |dsym| dsym.flush(self) catch |err| switch (err) {
605	error.OutOfMemory => |e| return e,
606	else => |e| return diags.fail("failed to get debug symbols: {s}", .{@errorName(e)}),
607	};
608
609	// Code signing always comes last.
610	if (codesig) |*csig| {
611	self.writeCodeSignature(csig) catch |err| switch (err) {
612	error.OutOfMemory, error.AlreadyReported => |e| return e,
613	else => |e| return diags.fail("failed to write code signature: {s}", .{@errorName(e)}),
614	};
615	const emit = self.base.emit;
616	invalidateKernelCache(io, emit.root_dir.handle, emit.sub_path) catch |err| switch (err) {
617	else => |e| return diags.fail("failed to invalidate kernel cache: {t}", .{e}),
618	};
619	}
620	}
621
622	/// --verbose-link output
623	fn dumpArgv(self: *MachO, comp: *Compilation) !void {
624	const gpa = comp.gpa;
625	const io = comp.io;
626
627	var arena_allocator = std.heap.ArenaAllocator.init(gpa);
628	defer arena_allocator.deinit();
629	const arena = arena_allocator.allocator();
630
631	const directory = self.base.emit.root_dir;
632	const full_out_path = try directory.join(arena, &[_][]const u8{self.base.emit.sub_path});
633	const zcu_obj_path: ?[]const u8 = p: {
634	const zcu = comp.zcu orelse break :p null;
635	const llvm_object = zcu.llvm_object orelse break :p null;
636	const p = try comp.resolveEmitPathFlush(arena, .temp, llvm_object.out_bin_basename);
637	break :p try p.toString(arena);
638	};
639
640	var argv = std.array_list.Managed([]const u8).init(arena);
641
642	try argv.append("zig");
643
644	if (self.base.isStaticLib()) {
645	try argv.append("ar");
646	} else {
647	try argv.append("ld");
648	}
649
650	if (self.base.isObject()) {
651	try argv.append("-r");
652	}
653
654	if (self.base.isRelocatable()) {
655	for (comp.link_inputs) |link_input| switch (link_input) {
656	.object, .archive => |obj| try argv.append(try obj.path.toString(arena)),
657	.res => |res| try argv.append(try res.path.toString(arena)),
658	.dso => |dso| try argv.append(try dso.path.toString(arena)),
659	.dso_exact => |dso_exact| try argv.appendSlice(&.{ "-l", dso_exact.name }),
660	};
661
662	for (comp.c_objects.items) |c_object| {
663	try argv.append(try c_object.status.success.object_path.toString(arena));
664	}
665
666	if (zcu_obj_path) |p| {
667	try argv.append(p);
668	}
669	} else {
670	if (!self.base.isStatic()) {
671	try argv.append("-dynamic");
672	}
673
674	if (self.base.isDynLib()) {
675	try argv.append("-dylib");
676
677	if (self.install_name) |install_name| {
678	try argv.append("-install_name");
679	try argv.append(install_name);
680	}
681	}
682
683	try argv.append("-platform_version");
684	try argv.append(@tagName(self.platform.os_tag));
685	try argv.append(try std.fmt.allocPrint(arena, "{f}", .{self.platform.version}));
686
687	if (self.sdk_version) |ver| {
688	try argv.append(try std.fmt.allocPrint(arena, "{d}.{d}", .{ ver.major, ver.minor }));
689	} else {
690	try argv.append(try std.fmt.allocPrint(arena, "{f}", .{self.platform.version}));
691	}
692
693	if (comp.sysroot) |syslibroot| {
694	try argv.append("-syslibroot");
695	try argv.append(syslibroot);
696	}
697
698	for (self.rpath_list) |rpath| {
699	try argv.appendSlice(&.{ "-rpath", rpath });
700	}
701
702	if (self.pagezero_size) |size| {
703	try argv.append("-pagezero_size");
704	try argv.append(try std.fmt.allocPrint(arena, "0x{x}", .{size}));
705	}
706
707	if (self.headerpad_size) |size| {
708	try argv.append("-headerpad_size");
709	try argv.append(try std.fmt.allocPrint(arena, "0x{x}", .{size}));
710	}
711
712	if (self.headerpad_max_install_names) {
713	try argv.append("-headerpad_max_install_names");
714	}
715
716	if (self.base.gc_sections) {
717	try argv.append("-dead_strip");
718	}
719
720	if (self.dead_strip_dylibs) {
721	try argv.append("-dead_strip_dylibs");
722	}
723
724	if (self.force_load_objc) {
725	try argv.append("-ObjC");
726	}
727
728	if (self.discard_local_symbols) {
729	try argv.append("-x");
730	}
731
732	if (self.entry_name) |entry_name| {
733	try argv.appendSlice(&.{ "-e", entry_name });
734	}
735
736	try argv.append("-o");
737	try argv.append(full_out_path);
738
739	if (self.base.isDynLib() and self.base.allow_shlib_undefined) {
740	try argv.append("-undefined");
741	try argv.append("dynamic_lookup");
742	}
743
744	for (comp.link_inputs) |link_input| switch (link_input) {
745	.dso => continue, // handled below
746	.res => unreachable, // windows only
747	.object, .archive => |obj| {
748	if (obj.must_link) try argv.append("-force_load"); // TODO: verify this
749	try argv.append(try obj.path.toString(arena));
750	},
751	.dso_exact => |dso_exact| try argv.appendSlice(&.{ "-l", dso_exact.name }),
752	};
753
754	for (comp.c_objects.items) |c_object| {
755	try argv.append(try c_object.status.success.object_path.toString(arena));
756	}
757
758	if (zcu_obj_path) |p| {
759	try argv.append(p);
760	}
761
762	if (comp.config.any_sanitize_thread) {
763	const path = try comp.tsan_lib.?.full_object_path.toString(arena);
764	try argv.appendSlice(&.{ path, "-rpath", std.fs.path.dirname(path) orelse "." });
765	}
766
767	if (comp.config.any_fuzz) {
768	try argv.append(try comp.fuzzer_lib.?.full_object_path.toString(arena));
769	}
770
771	for (self.lib_directories) |lib_directory| {
772	// TODO delete this, directories must instead be resolved by the frontend
773	const arg = try std.fmt.allocPrint(arena, "-L{s}", .{lib_directory.path orelse "."});
774	try argv.append(arg);
775	}
776
777	for (comp.link_inputs) |link_input| switch (link_input) {
778	.object, .archive, .dso_exact => continue, // handled above
779	.res => unreachable, // windows only
780	.dso => |dso| {
781	if (dso.needed) {
782	try argv.appendSlice(&.{ "-needed-l", try dso.path.toString(arena) });
783	} else if (dso.weak) {
784	try argv.appendSlice(&.{ "-weak-l", try dso.path.toString(arena) });
785	} else {
786	try argv.appendSlice(&.{ "-l", try dso.path.toString(arena) });
787	}
788	},
789	};
790
791	for (self.framework_dirs) |f_dir| {
792	try argv.append("-F");
793	try argv.append(f_dir);
794	}
795
796	for (self.frameworks) |framework| {
797	const name = framework.path.stem();
798	const arg = if (framework.needed)
799	try std.fmt.allocPrint(arena, "-needed_framework {s}", .{name})
800	else if (framework.weak)
801	try std.fmt.allocPrint(arena, "-weak_framework {s}", .{name})
802	else
803	try std.fmt.allocPrint(arena, "-framework {s}", .{name});
804	try argv.append(arg);
805	}
806
807	if (comp.config.link_libcpp) {
808	try argv.appendSlice(&.{
809	try comp.libcxxabi_static_lib.?.full_object_path.toString(arena),
810	try comp.libcxx_static_lib.?.full_object_path.toString(arena),
811	});
812	}
813
814	try argv.append("-lSystem");
815
816	if (comp.zigc_static_lib) |lib| try argv.append(try lib.full_object_path.toString(arena));
817	if (comp.compiler_rt_lib) |lib| try argv.append(try lib.full_object_path.toString(arena));
818	if (comp.compiler_rt_obj) |obj| try argv.append(try obj.full_object_path.toString(arena));
819	if (comp.ubsan_rt_lib) |lib| try argv.append(try lib.full_object_path.toString(arena));
820	if (comp.ubsan_rt_obj) |obj| try argv.append(try obj.full_object_path.toString(arena));
821	}
822
823	try Compilation.dumpArgv(io, argv.items);
824	}
825
826	/// TODO delete this, libsystem must be resolved when setting up the compilation pipeline
827	pub fn resolveLibSystem(
828	self: *MachO,
829	arena: Allocator,
830	comp: *Compilation,
831	out_libs: anytype,
832	) !void {
833	const io = comp.io;
834	const diags = &comp.link_diags;
835
836	var test_path = std.array_list.Managed(u8).init(arena);
837	var checked_paths = std.array_list.Managed([]const u8).init(arena);
838
839	success: {
840	if (self.sdk_layout) |sdk_layout| switch (sdk_layout) {
841	.sdk => {
842	const dir = try fs.path.join(arena, &.{ comp.sysroot.?, "usr", "lib" });
843	if (try accessLibPath(arena, io, &test_path, &checked_paths, dir, "System")) break :success;
844	},
845	.vendored => {
846	const dir = try comp.dirs.zig_lib.join(arena, &.{ "libc", "darwin" });
847	if (try accessLibPath(arena, io, &test_path, &checked_paths, dir, "System")) break :success;
848	},
849	};
850
851	for (self.lib_directories) |directory| {
852	if (try accessLibPath(arena, io, &test_path, &checked_paths, directory.path orelse ".", "System")) break :success;
853	}
854
855	diags.addMissingLibraryError(checked_paths.items, "unable to find libSystem system library", .{});
856	return error.MissingLibSystem;
857	}
858
859	const libsystem_path = Path.initCwd(try arena.dupe(u8, test_path.items));
860	try out_libs.append(.{
861	.needed = true,
862	.path = libsystem_path,
863	});
864	}
865
866	pub fn classifyInputFile(self: *MachO, input: link.Input) !void {
867	const tracy = trace(@src());
868	defer tracy.end();
869
870	const comp = self.base.comp;
871	const io = comp.io;
872
873	const path, const file = input.pathAndFile().?;
874	// TODO don't classify now, it's too late. The input file has already been classified
875	log.debug("classifying input file {f}", .{path});
876
877	const fh = try self.addFileHandle(file);
878	var buffer: [Archive.SARMAG]u8 = undefined;
879
880	const fat_arch: ?fat.Arch = try self.parseFatFile(file, path);
881	const offset = if (fat_arch) |fa| fa.offset else 0;
882
883	if (readMachHeader(io, file, offset) catch null) |h| blk: {
884	if (h.magic != macho.MH_MAGIC_64) break :blk;
885	switch (h.filetype) {
886	macho.MH_OBJECT => try self.addObject(path, fh, offset),
887	macho.MH_DYLIB => _ = try self.addDylib(.fromLinkInput(input), true, fh, offset),
888	else => return error.UnknownFileType,
889	}
890	return;
891	}
892	if (readArMagic(io, file, offset, &buffer) catch null) |ar_magic| blk: {
893	if (!mem.eql(u8, ar_magic, Archive.ARMAG)) break :blk;
894	try self.addArchive(input.archive, fh, fat_arch);
895	return;
896	}
897	_ = try self.addTbd(.fromLinkInput(input), true, fh);
898	}
899
900	fn parseFatFile(self: *MachO, file: Io.File, path: Path) !?fat.Arch {
901	const comp = self.base.comp;
902	const io = comp.io;
903	const diags = &comp.link_diags;
904	const fat_h = fat.readFatHeader(io, file) catch return null;
905	if (fat_h.magic != macho.FAT_MAGIC and fat_h.magic != macho.FAT_MAGIC_64) return null;
906	var fat_archs_buffer: [2]fat.Arch = undefined;
907	const fat_archs = try fat.parseArchs(io, file, fat_h, &fat_archs_buffer);
908	const cpu_arch = self.getTarget().cpu.arch;
909	for (fat_archs) |arch| {
910	if (arch.tag == cpu_arch) return arch;
911	}
912	return diags.failParse(path, "missing arch in universal file: expected {s}", .{@tagName(cpu_arch)});
913	}
914
915	pub fn readMachHeader(io: Io, file: Io.File, offset: usize) !macho.mach_header_64 {
916	var buffer: [@sizeOf(macho.mach_header_64)]u8 = undefined;
917	const nread = try file.readPositionalAll(io, &buffer, offset);
918	if (nread != buffer.len) return error.InputOutput;
919	const hdr = @as(*align(1) const macho.mach_header_64, @ptrCast(&buffer)).*;
920	return hdr;
921	}
922
923	pub fn readArMagic(io: Io, file: Io.File, offset: usize, buffer: *[Archive.SARMAG]u8) ![]const u8 {
924	const nread = try file.readPositionalAll(io, buffer, offset);
925	if (nread != buffer.len) return error.InputOutput;
926	return buffer[0..Archive.SARMAG];
927	}
928
929	fn addObject(self: *MachO, path: Path, handle_index: File.HandleIndex, offset: u64) !void {
930	const tracy = trace(@src());
931	defer tracy.end();
932
933	const comp = self.base.comp;
934	const gpa = comp.gpa;
935	const io = comp.io;
936
937	const abs_path = try std.fs.path.resolvePosix(gpa, &.{
938	comp.dirs.cwd,
939	path.root_dir.path orelse ".",
940	path.sub_path,
941	});
942	errdefer gpa.free(abs_path);
943
944	const file = self.getFileHandle(handle_index);
945	const stat = try file.stat(io);
946	const mtime = stat.mtime.toSeconds();
947	const index: File.Index = @intCast(try self.files.addOne(gpa));
948	self.files.set(index, .{ .object = .{
949	.offset = offset,
950	.path = abs_path,
951	.file_handle = handle_index,
952	.mtime = @intCast(mtime),
953	.index = index,
954	} });
955	try self.objects.append(gpa, index);
956	}
957
958	pub fn parseInputFiles(self: *MachO) !void {
959	const tracy = trace(@src());
960	defer tracy.end();
961
962	const diags = &self.base.comp.link_diags;
963
964	{
965	for (self.objects.items) |index| {
966	parseInputFileWorker(self, self.getFile(index).?);
967	}
968	for (self.dylibs.items) |index| {
969	parseInputFileWorker(self, self.getFile(index).?);
970	}
971	}
972
973	if (diags.hasErrors()) return error.AlreadyReported;
974	}
975
976	fn parseInputFileWorker(self: *MachO, file: File) void {
977	file.parse(self) catch |err| {
978	switch (err) {
979	error.MalformedObject,
980	error.MalformedDylib,
981	error.MalformedTbd,
982	error.InvalidMachineType,
983	error.InvalidTarget,
984	=> {}, // already reported
985
986	else => |e| self.reportParseError2(file.getIndex(), "unexpected error: parsing input file failed with error {s}", .{@errorName(e)}) catch {},
987	}
988	};
989	}
990
991	fn addArchive(self: *MachO, lib: link.Input.Object, handle: File.HandleIndex, fat_arch: ?fat.Arch) !void {
992	const tracy = trace(@src());
993	defer tracy.end();
994
995	if (self.base.isStaticLib()) {
996	// Ignore static library inputs when generating a static library.
997	return;
998	}
999
1000	const gpa = self.base.comp.gpa;
1001
1002	var archive: Archive = .{};
1003	defer archive.deinit(gpa);
1004	try archive.unpack(self, lib.path, handle, fat_arch);
1005
1006	for (archive.objects.items) |unpacked| {
1007	const index: File.Index = @intCast(try self.files.addOne(gpa));
1008	self.files.set(index, .{ .object = unpacked });
1009	const object = &self.files.items(.data)[index].object;
1010	object.index = index;
1011	object.alive = lib.must_link; // TODO: or self.options.all_load;
1012	object.hidden = lib.hidden;
1013	try self.objects.append(gpa, index);
1014	}
1015	}
1016
1017	fn addDylib(self: *MachO, lib: SystemLib, explicit: bool, handle: File.HandleIndex, offset: u64) !File.Index {
1018	const tracy = trace(@src());
1019	defer tracy.end();
1020
1021	const gpa = self.base.comp.gpa;
1022
1023	const index: File.Index = @intCast(try self.files.addOne(gpa));
1024	self.files.set(index, .{ .dylib = .{
1025	.offset = offset,
1026	.file_handle = handle,
1027	.tag = .dylib,
1028	.path = .{
1029	.root_dir = lib.path.root_dir,
1030	.sub_path = try gpa.dupe(u8, lib.path.sub_path),
1031	},
1032	.index = index,
1033	.needed = lib.needed,
1034	.weak = lib.weak,
1035	.reexport = lib.reexport,
1036	.explicit = explicit,
1037	.umbrella = index,
1038	} });
1039	try self.dylibs.append(gpa, index);
1040
1041	return index;
1042	}
1043
1044	fn addTbd(self: *MachO, lib: SystemLib, explicit: bool, handle: File.HandleIndex) !File.Index {
1045	const tracy = trace(@src());
1046	defer tracy.end();
1047
1048	const gpa = self.base.comp.gpa;
1049	const index: File.Index = @intCast(try self.files.addOne(gpa));
1050	self.files.set(index, .{ .dylib = .{
1051	.offset = 0,
1052	.file_handle = handle,
1053	.tag = .tbd,
1054	.path = .{
1055	.root_dir = lib.path.root_dir,
1056	.sub_path = try gpa.dupe(u8, lib.path.sub_path),
1057	},
1058	.index = index,
1059	.needed = lib.needed,
1060	.weak = lib.weak,
1061	.reexport = lib.reexport,
1062	.explicit = explicit,
1063	.umbrella = index,
1064	} });
1065	try self.dylibs.append(gpa, index);
1066
1067	return index;
1068	}
1069
1070	/// According to ld64's manual, public (i.e., system) dylibs/frameworks are hoisted into the final
1071	/// image unless overriden by -no_implicit_dylibs.
1072	fn isHoisted(self: *MachO, install_name: []const u8) bool {
1073	if (self.no_implicit_dylibs) return true;
1074	if (fs.path.dirname(install_name)) |dirname| {
1075	if (mem.startsWith(u8, dirname, "/usr/lib")) return true;
1076	if (eatPrefix(dirname, "/System/Library/Frameworks/")) |path| {
1077	const basename = fs.path.basename(install_name);
1078	if (mem.findScalar(u8, path, '.')) |index| {
1079	if (mem.eql(u8, basename, path[0..index])) return true;
1080	}
1081	}
1082	}
1083	return false;
1084	}
1085
1086	/// TODO delete this, libraries must be instead resolved when instantiating the compilation pipeline
1087	fn accessLibPath(
1088	arena: Allocator,
1089	io: Io,
1090	test_path: *std.array_list.Managed(u8),
1091	checked_paths: *std.array_list.Managed([]const u8),
1092	search_dir: []const u8,
1093	name: []const u8,
1094	) !bool {
1095	const sep = fs.path.sep_str;
1096
1097	for (&[_][]const u8{ ".tbd", ".dylib", "" }) |ext| {
1098	test_path.clearRetainingCapacity();
1099	try test_path.print("{s}" ++ sep ++ "lib{s}{s}", .{ search_dir, name, ext });
1100	try checked_paths.append(try arena.dupe(u8, test_path.items));
1101	Io.Dir.cwd().access(io, test_path.items, .{}) catch |err| switch (err) {
1102	error.FileNotFound => continue,
1103	else => |e| return e,
1104	};
1105	return true;
1106	}
1107
1108	return false;
1109	}
1110
1111	fn accessFrameworkPath(
1112	arena: Allocator,
1113	io: Io,
1114	test_path: *std.array_list.Managed(u8),
1115	checked_paths: *std.array_list.Managed([]const u8),
1116	search_dir: []const u8,
1117	name: []const u8,
1118	) !bool {
1119	const sep = fs.path.sep_str;
1120
1121	for (&[_][]const u8{ ".tbd", ".dylib", "" }) |ext| {
1122	test_path.clearRetainingCapacity();
1123	try test_path.print("{s}" ++ sep ++ "{s}.framework" ++ sep ++ "{s}{s}", .{
1124	search_dir,
1125	name,
1126	name,
1127	ext,
1128	});
1129	try checked_paths.append(try arena.dupe(u8, test_path.items));
1130	Io.Dir.cwd().access(io, test_path.items, .{}) catch |err| switch (err) {
1131	error.FileNotFound => continue,
1132	else => |e| return e,
1133	};
1134	return true;
1135	}
1136
1137	return false;
1138	}
1139
1140	fn parseDependentDylibs(self: *MachO) !void {
1141	const tracy = trace(@src());
1142	defer tracy.end();
1143
1144	if (self.dylibs.items.len == 0) return;
1145
1146	const comp = self.base.comp;
1147	const gpa = comp.gpa;
1148	const io = comp.io;
1149	const framework_dirs = self.framework_dirs;
1150
1151	// TODO delete this, directories must instead be resolved by the frontend
1152	const lib_directories = self.lib_directories;
1153
1154	var arena_alloc = std.heap.ArenaAllocator.init(gpa);
1155	defer arena_alloc.deinit();
1156	const arena = arena_alloc.allocator();
1157
1158	// TODO handle duplicate dylibs - it is not uncommon to have the same dylib loaded multiple times
1159	// in which case we should track that and return File.Index immediately instead re-parsing paths.
1160
1161	var has_errors = false;
1162	var index: usize = 0;
1163	while (index < self.dylibs.items.len) : (index += 1) {
1164	const dylib_index = self.dylibs.items[index];
1165
1166	var dependents = std.array_list.Managed(File.Index).init(gpa);
1167	defer dependents.deinit();
1168	try dependents.ensureTotalCapacityPrecise(self.getFile(dylib_index).?.dylib.dependents.items.len);
1169
1170	const is_weak = self.getFile(dylib_index).?.dylib.weak;
1171	for (self.getFile(dylib_index).?.dylib.dependents.items) |id| {
1172	// We will search for the dependent dylibs in the following order:
1173	// 1. Basename is in search lib directories or framework directories
1174	// 2. If name is an absolute path, search as-is optionally prepending a syslibroot
1175	// if specified.
1176	// 3. If name is a relative path, substitute @rpath, @loader_path, @executable_path with
1177	// dependees list of rpaths, and search there.
1178	// 4. Finally, just search the provided relative path directly in CWD.
1179	var test_path = std.array_list.Managed(u8).init(arena);
1180	var checked_paths = std.array_list.Managed([]const u8).init(arena);
1181
1182	const full_path = full_path: {
1183	{
1184	const stem = fs.path.stem(id.name);
1185
1186	// Framework
1187	for (framework_dirs) |dir| {
1188	test_path.clearRetainingCapacity();
1189	if (try accessFrameworkPath(arena, io, &test_path, &checked_paths, dir, stem)) break :full_path test_path.items;
1190	}
1191
1192	// Library
1193	const lib_name = eatPrefix(stem, "lib") orelse stem;
1194	for (lib_directories) |lib_directory| {
1195	test_path.clearRetainingCapacity();
1196	if (try accessLibPath(arena, io, &test_path, &checked_paths, lib_directory.path orelse ".", lib_name)) break :full_path test_path.items;
1197	}
1198	}
1199
1200	if (fs.path.isAbsolute(id.name)) {
1201	const existing_ext = fs.path.extension(id.name);
1202	const path = if (existing_ext.len > 0) id.name[0 .. id.name.len - existing_ext.len] else id.name;
1203	for (&[_][]const u8{ ".tbd", ".dylib", "" }) |ext| {
1204	test_path.clearRetainingCapacity();
1205	if (comp.sysroot) |root| {
1206	try test_path.print("{s}" ++ fs.path.sep_str ++ "{s}{s}", .{ root, path, ext });
1207	} else {
1208	try test_path.print("{s}{s}", .{ path, ext });
1209	}
1210	try checked_paths.append(try arena.dupe(u8, test_path.items));
1211	Io.Dir.cwd().access(io, test_path.items, .{}) catch |err| switch (err) {
1212	error.FileNotFound => continue,
1213	else => |e| return e,
1214	};
1215	break :full_path test_path.items;
1216	}
1217	}
1218
1219	if (eatPrefix(id.name, "@rpath/")) |path| {
1220	const dylib = self.getFile(dylib_index).?.dylib;
1221	for (self.getFile(dylib.umbrella).?.dylib.rpaths.keys()) |rpath| {
1222	const prefix = eatPrefix(rpath, "@loader_path/") orelse rpath;
1223	const rel_path = try fs.path.join(arena, &.{ prefix, path });
1224	try checked_paths.append(rel_path);
1225	var buffer: [fs.max_path_bytes]u8 = undefined;
1226	// TODO don't use realpath
1227	const full_path = buffer[0 .. Io.Dir.realPathFileAbsolute(io, rel_path, &buffer) catch continue];
1228	break :full_path try arena.dupe(u8, full_path);
1229	}
1230	} else if (eatPrefix(id.name, "@loader_path/")) |_| {
1231	try self.reportParseError2(dylib_index, "TODO handle install_name '{s}'", .{id.name});
1232	return error.Unhandled;
1233	} else if (eatPrefix(id.name, "@executable_path/")) |_| {
1234	try self.reportParseError2(dylib_index, "TODO handle install_name '{s}'", .{id.name});
1235	return error.Unhandled;
1236	}
1237
1238	try checked_paths.append(try arena.dupe(u8, id.name));
1239	var buffer: [fs.max_path_bytes]u8 = undefined;
1240	// TODO don't use realpath
1241	if (Io.Dir.realPathFileAbsolute(io, id.name, &buffer)) |full_path_n| {
1242	break :full_path try arena.dupe(u8, buffer[0..full_path_n]);
1243	} else |_| {
1244	try self.reportMissingDependencyError(
1245	self.getFile(dylib_index).?.dylib.getUmbrella(self).index,
1246	id.name,
1247	checked_paths.items,
1248	"unable to resolve dependency",
1249	.{},
1250	);
1251	has_errors = true;
1252	continue;
1253	}
1254	};
1255	const lib: SystemLib = .{
1256	.path = Path.initCwd(full_path),
1257	.weak = is_weak,
1258	};
1259	const file = try lib.path.root_dir.handle.openFile(io, lib.path.sub_path, .{});
1260	const fh = try self.addFileHandle(file);
1261	const fat_arch = try self.parseFatFile(file, lib.path);
1262	const offset = if (fat_arch) |fa| fa.offset else 0;
1263	const file_index = file_index: {
1264	if (readMachHeader(io, file, offset) catch null) |h| blk: {
1265	if (h.magic != macho.MH_MAGIC_64) break :blk;
1266	switch (h.filetype) {
1267	macho.MH_DYLIB => break :file_index try self.addDylib(lib, false, fh, offset),
1268	else => break :file_index @as(File.Index, 0),
1269	}
1270	}
1271	break :file_index try self.addTbd(lib, false, fh);
1272	};
1273	dependents.appendAssumeCapacity(file_index);
1274	}
1275
1276	const dylib = self.getFile(dylib_index).?.dylib;
1277	for (dylib.dependents.items, dependents.items) |id, file_index| {
1278	if (self.getFile(file_index)) |file| {
1279	const dep_dylib = file.dylib;
1280	try dep_dylib.parse(self); // TODO in parallel
1281	dep_dylib.hoisted = self.isHoisted(id.name);
1282	dep_dylib.umbrella = dylib.umbrella;
1283	if (!dep_dylib.hoisted) {
1284	const umbrella = dep_dylib.getUmbrella(self);
1285	for (dep_dylib.exports.items(.name), dep_dylib.exports.items(.flags)) |off, flags| {
1286	// TODO rethink this entire algorithm
1287	try umbrella.addExport(gpa, dep_dylib.getString(off), flags);
1288	}
1289	try umbrella.rpaths.ensureUnusedCapacity(gpa, dep_dylib.rpaths.keys().len);
1290	for (dep_dylib.rpaths.keys()) |rpath| {
1291	umbrella.rpaths.putAssumeCapacity(try gpa.dupe(u8, rpath), {});
1292	}
1293	}
1294	} else try self.reportDependencyError(
1295	dylib.getUmbrella(self).index,
1296	id.name,
1297	"unable to resolve dependency",
1298	.{},
1299	);
1300	has_errors = true;
1301	}
1302	}
1303
1304	if (has_errors) return error.MissingLibraryDependencies;
1305	}
1306
1307	/// When resolving symbols, we approach the problem similarly to `mold`.
1308	/// 1. Resolve symbols across all objects (including those preemptively extracted archives).
1309	/// 2. Resolve symbols across all shared objects.
1310	/// 3. Mark live objects (see `MachO.markLive`)
1311	/// 4. Reset state of all resolved globals since we will redo this bit on the pruned set.
1312	/// 5. Remove references to dead objects/shared objects
1313	/// 6. Re-run symbol resolution on pruned objects and shared objects sets.
1314	pub fn resolveSymbols(self: *MachO) !void {
1315	const tracy = trace(@src());
1316	defer tracy.end();
1317
1318	// Resolve symbols in the ZigObject. For now, we assume that it's always live.
1319	if (self.getZigObject()) |zo| try zo.asFile().resolveSymbols(self);
1320	// Resolve symbols on the set of all objects and shared objects (even if some are unneeded).
1321	for (self.objects.items) |index| try self.getFile(index).?.resolveSymbols(self);
1322	for (self.dylibs.items) |index| try self.getFile(index).?.resolveSymbols(self);
1323	if (self.getInternalObject()) |obj| try obj.resolveSymbols(self);
1324
1325	// Mark live objects.
1326	self.markLive();
1327
1328	// Reset state of all globals after marking live objects.
1329	self.resolver.reset();
1330
1331	// Prune dead objects.
1332	var i: usize = 0;
1333	while (i < self.objects.items.len) {
1334	const index = self.objects.items[i];
1335	if (!self.getFile(index).?.object.alive) {
1336	_ = self.objects.orderedRemove(i);
1337	self.files.items(.data)[index].object.deinit(self.base.comp.gpa);
1338	self.files.set(index, .null);
1339	} else i += 1;
1340	}
1341
1342	// Re-resolve the symbols.
1343	if (self.getZigObject()) |zo| try zo.resolveSymbols(self);
1344	for (self.objects.items) |index| try self.getFile(index).?.resolveSymbols(self);
1345	for (self.dylibs.items) |index| try self.getFile(index).?.resolveSymbols(self);
1346	if (self.getInternalObject()) |obj| try obj.resolveSymbols(self);
1347
1348	// Merge symbol visibility
1349	if (self.getZigObject()) |zo| zo.mergeSymbolVisibility(self);
1350	for (self.objects.items) |index| self.getFile(index).?.object.mergeSymbolVisibility(self);
1351	}
1352
1353	fn markLive(self: *MachO) void {
1354	const tracy = trace(@src());
1355	defer tracy.end();
1356
1357	if (self.getZigObject()) |zo| zo.markLive(self);
1358	for (self.objects.items) |index| {
1359	const object = self.getFile(index).?.object;
1360	if (object.alive) object.markLive(self);
1361	}
1362	if (self.getInternalObject()) |obj| obj.markLive(self);
1363	}
1364
1365	fn convertTentativeDefsAndResolveSpecialSymbols(self: *MachO) !void {
1366	const diags = &self.base.comp.link_diags;
1367	{
1368	for (self.objects.items) |index| {
1369	convertTentativeDefinitionsWorker(self, self.getFile(index).?.object);
1370	}
1371	if (self.getInternalObject()) |obj| {
1372	resolveSpecialSymbolsWorker(self, obj);
1373	}
1374	}
1375	if (diags.hasErrors()) return error.AlreadyReported;
1376	}
1377
1378	fn convertTentativeDefinitionsWorker(self: *MachO, object: *Object) void {
1379	const tracy = trace(@src());
1380	defer tracy.end();
1381	object.convertTentativeDefinitions(self) catch |err| {
1382	self.reportParseError2(
1383	object.index,
1384	"unexpected error occurred while converting tentative symbols into defined symbols: {s}",
1385	.{@errorName(err)},
1386	) catch {};
1387	};
1388	}
1389
1390	fn resolveSpecialSymbolsWorker(self: *MachO, obj: *InternalObject) void {
1391	const tracy = trace(@src());
1392	defer tracy.end();
1393
1394	const diags = &self.base.comp.link_diags;
1395
1396	obj.resolveBoundarySymbols(self) catch |err|
1397	return diags.addError("failed to resolve boundary symbols: {s}", .{@errorName(err)});
1398	obj.resolveObjcMsgSendSymbols(self) catch |err|
1399	return diags.addError("failed to resolve ObjC msgsend stubs: {s}", .{@errorName(err)});
1400	}
1401
1402	pub fn dedupLiterals(self: *MachO) !void {
1403	const tracy = trace(@src());
1404	defer tracy.end();
1405
1406	const gpa = self.base.comp.gpa;
1407	var lp: LiteralPool = .{};
1408	defer lp.deinit(gpa);
1409
1410	if (self.getZigObject()) |zo| {
1411	try zo.resolveLiterals(&lp, self);
1412	}
1413	for (self.objects.items) |index| {
1414	try self.getFile(index).?.object.resolveLiterals(&lp, self);
1415	}
1416	if (self.getInternalObject()) |object| {
1417	try object.resolveLiterals(&lp, self);
1418	}
1419
1420	{
1421	if (self.getZigObject()) |zo| {
1422	File.dedupLiterals(zo.asFile(), lp, self);
1423	}
1424	for (self.objects.items) |index| {
1425	File.dedupLiterals(self.getFile(index).?, lp, self);
1426	}
1427	if (self.getInternalObject()) |object| {
1428	File.dedupLiterals(object.asFile(), lp, self);
1429	}
1430	}
1431	}
1432
1433	fn claimUnresolved(self: *MachO) void {
1434	if (self.getZigObject()) |zo| {
1435	zo.asFile().claimUnresolved(self);
1436	}
1437	for (self.objects.items) |index| {
1438	self.getFile(index).?.claimUnresolved(self);
1439	}
1440	}
1441
1442	fn checkDuplicates(self: *MachO) !void {
1443	const tracy = trace(@src());
1444	defer tracy.end();
1445
1446	const diags = &self.base.comp.link_diags;
1447
1448	{
1449	if (self.getZigObject()) |zo| {
1450	checkDuplicatesWorker(self, zo.asFile());
1451	}
1452	for (self.objects.items) |index| {
1453	checkDuplicatesWorker(self, self.getFile(index).?);
1454	}
1455	if (self.getInternalObject()) |obj| {
1456	checkDuplicatesWorker(self, obj.asFile());
1457	}
1458	}
1459
1460	if (diags.hasErrors()) return error.AlreadyReported;
1461
1462	try self.reportDuplicates();
1463	}
1464
1465	fn checkDuplicatesWorker(self: *MachO, file: File) void {
1466	const tracy = trace(@src());
1467	defer tracy.end();
1468	file.checkDuplicates(self) catch |err| {
1469	self.reportParseError2(file.getIndex(), "failed to check for duplicate definitions: {s}", .{
1470	@errorName(err),
1471	}) catch {};
1472	};
1473	}
1474
1475	fn markImportsAndExports(self: *MachO) void {
1476	const tracy = trace(@src());
1477	defer tracy.end();
1478
1479	if (self.getZigObject()) |zo| {
1480	zo.asFile().markImportsExports(self);
1481	}
1482	for (self.objects.items) |index| {
1483	self.getFile(index).?.markImportsExports(self);
1484	}
1485	if (self.getInternalObject()) |obj| {
1486	obj.asFile().markImportsExports(self);
1487	}
1488	}
1489
1490	fn deadStripDylibs(self: *MachO) void {
1491	const tracy = trace(@src());
1492	defer tracy.end();
1493
1494	for (self.dylibs.items) |index| {
1495	self.getFile(index).?.dylib.markReferenced(self);
1496	}
1497
1498	var i: usize = 0;
1499	while (i < self.dylibs.items.len) {
1500	const index = self.dylibs.items[i];
1501	if (!self.getFile(index).?.dylib.isAlive(self)) {
1502	_ = self.dylibs.orderedRemove(i);
1503	self.files.items(.data)[index].dylib.deinit(self.base.comp.gpa);
1504	self.files.set(index, .null);
1505	} else i += 1;
1506	}
1507	}
1508
1509	fn scanRelocs(self: *MachO) !void {
1510	const tracy = trace(@src());
1511	defer tracy.end();
1512
1513	const diags = &self.base.comp.link_diags;
1514
1515	{
1516	if (self.getZigObject()) |zo| {
1517	scanRelocsWorker(self, zo.asFile());
1518	}
1519	for (self.objects.items) |index| {
1520	scanRelocsWorker(self, self.getFile(index).?);
1521	}
1522	if (self.getInternalObject()) |obj| {
1523	scanRelocsWorker(self, obj.asFile());
1524	}
1525	}
1526
1527	if (diags.hasErrors()) return error.AlreadyReported;
1528
1529	if (self.getInternalObject()) |obj| {
1530	try obj.checkUndefs(self);
1531	}
1532	try self.reportUndefs();
1533
1534	if (self.getZigObject()) |zo| {
1535	try zo.asFile().createSymbolIndirection(self);
1536	}
1537	for (self.objects.items) |index| {
1538	try self.getFile(index).?.createSymbolIndirection(self);
1539	}
1540	for (self.dylibs.items) |index| {
1541	try self.getFile(index).?.createSymbolIndirection(self);
1542	}
1543	if (self.getInternalObject()) |obj| {
1544	try obj.asFile().createSymbolIndirection(self);
1545	}
1546	}
1547
1548	fn scanRelocsWorker(self: *MachO, file: File) void {
1549	file.scanRelocs(self) catch |err| {
1550	self.reportParseError2(file.getIndex(), "failed to scan relocations: {s}", .{
1551	@errorName(err),
1552	}) catch {};
1553	};
1554	}
1555
1556	fn sortGlobalSymbolsByName(self: *MachO, symbols: []SymbolResolver.Index) void {
1557	const lessThan = struct {
1558	fn lessThan(ctx: *MachO, lhs: SymbolResolver.Index, rhs: SymbolResolver.Index) bool {
1559	const lhs_name = ctx.resolver.keys.items[lhs - 1].getName(ctx);
1560	const rhs_name = ctx.resolver.keys.items[rhs - 1].getName(ctx);
1561	return mem.order(u8, lhs_name, rhs_name) == .lt;
1562	}
1563	}.lessThan;
1564	mem.sort(SymbolResolver.Index, symbols, self, lessThan);
1565	}
1566
1567	fn reportUndefs(self: *MachO) !void {
1568	const tracy = trace(@src());
1569	defer tracy.end();
1570
1571	if (self.undefined_treatment == .suppress or
1572	self.undefined_treatment == .dynamic_lookup) return;
1573	if (self.undefs.keys().len == 0) return; // Nothing to do
1574
1575	const gpa = self.base.comp.gpa;
1576	const diags = &self.base.comp.link_diags;
1577	const max_notes = 4;
1578
1579	// We will sort by name, and then by file to ensure deterministic output.
1580	var keys = try std.array_list.Managed(SymbolResolver.Index).initCapacity(gpa, self.undefs.keys().len);
1581	defer keys.deinit();
1582	keys.appendSliceAssumeCapacity(self.undefs.keys());
1583	self.sortGlobalSymbolsByName(keys.items);
1584
1585	const refLessThan = struct {
1586	fn lessThan(ctx: void, lhs: Ref, rhs: Ref) bool {
1587	_ = ctx;
1588	return lhs.lessThan(rhs);
1589	}
1590	}.lessThan;
1591
1592	for (self.undefs.values()) |*undefs| switch (undefs.*) {
1593	.refs => |refs| mem.sort(Ref, refs.items, {}, refLessThan),
1594	else => {},
1595	};
1596
1597	for (keys.items) |key| {
1598	const undef_sym = self.resolver.keys.items[key - 1];
1599	const notes = self.undefs.get(key).?;
1600	const nnotes = nnotes: {
1601	const nnotes = switch (notes) {
1602	.refs => |refs| refs.items.len,
1603	else => 1,
1604	};
1605	break :nnotes @min(nnotes, max_notes) + @intFromBool(nnotes > max_notes);
1606	};
1607
1608	var err = try diags.addErrorWithNotes(nnotes);
1609	try err.addMsg("undefined symbol: {s}", .{undef_sym.getName(self)});
1610
1611	switch (notes) {
1612	.force_undefined => err.addNote("referenced with linker flag -u", .{}),
1613	.entry => err.addNote("referenced with linker flag -e", .{}),
1614	.dyld_stub_binder, .objc_msgsend => err.addNote("referenced implicitly", .{}),
1615	.refs => |refs| {
1616	var inote: usize = 0;
1617	while (inote < @min(refs.items.len, max_notes)) : (inote += 1) {
1618	const ref = refs.items[inote];
1619	const file = self.getFile(ref.file).?;
1620	const atom = ref.getAtom(self).?;
1621	err.addNote("referenced by {f}:{s}", .{ file.fmtPath(), atom.getName(self) });
1622	}
1623
1624	if (refs.items.len > max_notes) {
1625	const remaining = refs.items.len - max_notes;
1626	err.addNote("referenced {d} more times", .{remaining});
1627	}
1628	},
1629	}
1630	}
1631
1632	return error.HasUndefinedSymbols;
1633	}
1634
1635	fn initOutputSections(self: *MachO) !void {
1636	const tracy = trace(@src());
1637	defer tracy.end();
1638
1639	for (self.objects.items) |index| {
1640	try self.getFile(index).?.initOutputSections(self);
1641	}
1642	if (self.getInternalObject()) |obj| {
1643	try obj.asFile().initOutputSections(self);
1644	}
1645	self.text_sect_index = self.getSectionByName("__TEXT", "__text") orelse
1646	try self.addSection("__TEXT", "__text", .{
1647	.alignment = switch (self.getTarget().cpu.arch) {
1648	.x86_64 => 0,
1649	.aarch64 => 2,
1650	else => unreachable,
1651	},
1652	.flags = macho.S_REGULAR |
1653	macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS,
1654	});
1655	self.data_sect_index = self.getSectionByName("__DATA", "__data") orelse
1656	try self.addSection("__DATA", "__data", .{});
1657	}
1658
1659	fn initSyntheticSections(self: *MachO) !void {
1660	const cpu_arch = self.getTarget().cpu.arch;
1661
1662	if (self.got.symbols.items.len > 0) {
1663	self.got_sect_index = try self.addSection("__DATA_CONST", "__got", .{
1664	.flags = macho.S_NON_LAZY_SYMBOL_POINTERS,
1665	.reserved1 = @intCast(self.stubs.symbols.items.len),
1666	});
1667	}
1668
1669	if (self.stubs.symbols.items.len > 0) {
1670	self.stubs_sect_index = try self.addSection("__TEXT", "__stubs", .{
1671	.flags = macho.S_SYMBOL_STUBS |
1672	macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS,
1673	.reserved1 = 0,
1674	.reserved2 = switch (cpu_arch) {
1675	.x86_64 => 6,
1676	.aarch64 => 3 * @sizeOf(u32),
1677	else => 0,
1678	},
1679	});
1680	self.stubs_helper_sect_index = try self.addSection("__TEXT", "__stub_helper", .{
1681	.flags = macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS,
1682	});
1683	self.la_symbol_ptr_sect_index = try self.addSection("__DATA", "__la_symbol_ptr", .{
1684	.flags = macho.S_LAZY_SYMBOL_POINTERS,
1685	.reserved1 = @intCast(self.stubs.symbols.items.len + self.got.symbols.items.len),
1686	});
1687	}
1688
1689	if (self.objc_stubs.symbols.items.len > 0) {
1690	self.objc_stubs_sect_index = try self.addSection("__TEXT", "__objc_stubs", .{
1691	.flags = macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS,
1692	});
1693	}
1694
1695	if (self.tlv_ptr.symbols.items.len > 0) {
1696	self.tlv_ptr_sect_index = try self.addSection("__DATA", "__thread_ptrs", .{
1697	.flags = macho.S_THREAD_LOCAL_VARIABLE_POINTERS,
1698	});
1699	}
1700
1701	const needs_unwind_info = for (self.objects.items) |index| {
1702	if (self.getFile(index).?.object.hasUnwindRecords()) break true;
1703	} else false;
1704	if (needs_unwind_info) {
1705	self.unwind_info_sect_index = try self.addSection("__TEXT", "__unwind_info", .{});
1706	}
1707
1708	const needs_eh_frame = for (self.objects.items) |index| {
1709	if (self.getFile(index).?.object.hasEhFrameRecords()) break true;
1710	} else false;
1711	if (needs_eh_frame) {
1712	assert(needs_unwind_info);
1713	self.eh_frame_sect_index = try self.addSection("__TEXT", "__eh_frame", .{
1714	.flags = macho.S_COALESCED | macho.S_ATTR_NO_TOC | macho.S_ATTR_STRIP_STATIC_SYMS | macho.S_ATTR_LIVE_SUPPORT,
1715	});
1716	}
1717
1718	if (self.getInternalObject()) |obj| {
1719	const gpa = self.base.comp.gpa;
1720
1721	for (obj.boundary_symbols.items) |sym_index| {
1722	const ref = obj.getSymbolRef(sym_index, self);
1723	const sym = ref.getSymbol(self).?;
1724	const name = sym.getName(self);
1725
1726	if (eatPrefix(name, "segment$start$")) |segname| {
1727	if (self.getSegmentByName(segname) == null) { // TODO check segname is valid
1728	const prot = getSegmentProt(segname);
1729	_ = try self.segments.append(gpa, .{
1730	.cmdsize = @sizeOf(macho.segment_command_64),
1731	.segname = makeStaticString(segname),
1732	.initprot = prot,
1733	.maxprot = prot,
1734	});
1735	}
1736	} else if (eatPrefix(name, "segment$end$")) |segname| {
1737	if (self.getSegmentByName(segname) == null) { // TODO check segname is valid
1738	const prot = getSegmentProt(segname);
1739	_ = try self.segments.append(gpa, .{
1740	.cmdsize = @sizeOf(macho.segment_command_64),
1741	.segname = makeStaticString(segname),
1742	.initprot = prot,
1743	.maxprot = prot,
1744	});
1745	}
1746	} else if (eatPrefix(name, "section$start$")) |actual_name| {
1747	const sep = mem.findScalar(u8, actual_name, '$').?; // TODO error rather than a panic
1748	const segname = actual_name[0..sep]; // TODO check segname is valid
1749	const sectname = actual_name[sep + 1 ..]; // TODO check sectname is valid
1750	if (self.getSectionByName(segname, sectname) == null) {
1751	_ = try self.addSection(segname, sectname, .{});
1752	}
1753	} else if (eatPrefix(name, "section$end$")) |actual_name| {
1754	const sep = mem.findScalar(u8, actual_name, '$').?; // TODO error rather than a panic
1755	const segname = actual_name[0..sep]; // TODO check segname is valid
1756	const sectname = actual_name[sep + 1 ..]; // TODO check sectname is valid
1757	if (self.getSectionByName(segname, sectname) == null) {
1758	_ = try self.addSection(segname, sectname, .{});
1759	}
1760	} else unreachable;
1761	}
1762	}
1763	}
1764
1765	fn getSegmentProt(segname: []const u8) macho.vm_prot_t {
1766	if (mem.eql(u8, segname, "__PAGEZERO")) return .{};
1767	if (mem.eql(u8, segname, "__TEXT")) return .{ .READ = true, .EXEC = true };
1768	if (mem.eql(u8, segname, "__LINKEDIT")) return .{ .READ = true };
1769	return .{ .READ = true, .WRITE = true };
1770	}
1771
1772	fn getSegmentRank(segname: []const u8) u8 {
1773	if (mem.eql(u8, segname, "__PAGEZERO")) return 0x0;
1774	if (mem.eql(u8, segname, "__LINKEDIT")) return 0xf;
1775	if (mem.find(u8, segname, "ZIG")) |_| return 0xe;
1776	if (mem.startsWith(u8, segname, "__TEXT")) return 0x1;
1777	if (mem.startsWith(u8, segname, "__DATA_CONST")) return 0x2;
1778	if (mem.startsWith(u8, segname, "__DATA")) return 0x3;
1779	return 0x4;
1780	}
1781
1782	fn segmentLessThan(ctx: void, lhs: []const u8, rhs: []const u8) bool {
1783	_ = ctx;
1784	const lhs_rank = getSegmentRank(lhs);
1785	const rhs_rank = getSegmentRank(rhs);
1786	if (lhs_rank == rhs_rank) {
1787	return mem.order(u8, lhs, rhs) == .lt;
1788	}
1789	return lhs_rank < rhs_rank;
1790	}
1791
1792	fn getSectionRank(section: macho.section_64) u8 {
1793	if (section.isCode()) {
1794	if (mem.eql(u8, "__text", section.sectName())) return 0x0;
1795	if (section.type() == macho.S_SYMBOL_STUBS) return 0x1;
1796	return 0x2;
1797	}
1798	switch (section.type()) {
1799	macho.S_NON_LAZY_SYMBOL_POINTERS,
1800	macho.S_LAZY_SYMBOL_POINTERS,
1801	=> return 0x0,
1802
1803	macho.S_MOD_INIT_FUNC_POINTERS => return 0x1,
1804	macho.S_MOD_TERM_FUNC_POINTERS => return 0x2,
1805	macho.S_ZEROFILL => return 0xf,
1806	macho.S_THREAD_LOCAL_REGULAR => return 0xd,
1807	macho.S_THREAD_LOCAL_ZEROFILL => return 0xe,
1808
1809	else => {
1810	if (mem.eql(u8, "__unwind_info", section.sectName())) return 0xe;
1811	if (mem.eql(u8, "__compact_unwind", section.sectName())) return 0xe;
1812	if (mem.eql(u8, "__eh_frame", section.sectName())) return 0xf;
1813	return 0x3;
1814	},
1815	}
1816	}
1817
1818	fn sectionLessThan(ctx: void, lhs: macho.section_64, rhs: macho.section_64) bool {
1819	if (mem.eql(u8, lhs.segName(), rhs.segName())) {
1820	const lhs_rank = getSectionRank(lhs);
1821	const rhs_rank = getSectionRank(rhs);
1822	if (lhs_rank == rhs_rank) {
1823	return mem.order(u8, lhs.sectName(), rhs.sectName()) == .lt;
1824	}
1825	return lhs_rank < rhs_rank;
1826	}
1827	return segmentLessThan(ctx, lhs.segName(), rhs.segName());
1828	}
1829
1830	pub fn sortSections(self: *MachO) !void {
1831	const Entry = struct {
1832	index: u8,
1833
1834	pub fn lessThan(macho_file: *MachO, lhs: @This(), rhs: @This()) bool {
1835	return sectionLessThan(
1836	{},
1837	macho_file.sections.items(.header)[lhs.index],
1838	macho_file.sections.items(.header)[rhs.index],
1839	);
1840	}
1841	};
1842
1843	const gpa = self.base.comp.gpa;
1844
1845	var entries = try std.array_list.Managed(Entry).initCapacity(gpa, self.sections.slice().len);
1846	defer entries.deinit();
1847	for (0..self.sections.slice().len) |index| {
1848	entries.appendAssumeCapacity(.{ .index = @intCast(index) });
1849	}
1850
1851	mem.sort(Entry, entries.items, self, Entry.lessThan);
1852
1853	const backlinks = try gpa.alloc(u8, entries.items.len);
1854	defer gpa.free(backlinks);
1855	for (entries.items, 0..) |entry, i| {
1856	backlinks[entry.index] = @intCast(i);
1857	}
1858
1859	var slice = self.sections.toOwnedSlice();
1860	defer slice.deinit(gpa);
1861
1862	try self.sections.ensureTotalCapacity(gpa, slice.len);
1863	for (entries.items) |sorted| {
1864	self.sections.appendAssumeCapacity(slice.get(sorted.index));
1865	}
1866
1867	for (&[_]*?u8{
1868	&self.data_sect_index,
1869	&self.got_sect_index,
1870	&self.zig_text_sect_index,
1871	&self.zig_const_sect_index,
1872	&self.zig_data_sect_index,
1873	&self.zig_bss_sect_index,
1874	&self.stubs_sect_index,
1875	&self.stubs_helper_sect_index,
1876	&self.la_symbol_ptr_sect_index,
1877	&self.tlv_ptr_sect_index,
1878	&self.eh_frame_sect_index,
1879	&self.unwind_info_sect_index,
1880	&self.objc_stubs_sect_index,
1881	&self.debug_str_sect_index,
1882	&self.debug_info_sect_index,
1883	&self.debug_abbrev_sect_index,
1884	&self.debug_aranges_sect_index,
1885	&self.debug_line_sect_index,
1886	&self.debug_line_str_sect_index,
1887	&self.debug_loclists_sect_index,
1888	&self.debug_rnglists_sect_index,
1889	}) |maybe_index| {
1890	if (maybe_index.*) |*index| {
1891	index.* = backlinks[index.*];
1892	}
1893	}
1894
1895	if (self.getZigObject()) |zo| {
1896	for (zo.getAtoms()) |atom_index| {
1897	const atom = zo.getAtom(atom_index) orelse continue;
1898	if (!atom.isAlive()) continue;
1899	atom.out_n_sect = backlinks[atom.out_n_sect];
1900	}
1901	if (zo.dwarf) |*dwarf| dwarf.reloadSectionMetadata();
1902	}
1903
1904	for (self.objects.items) |index| {
1905	const file = self.getFile(index).?;
1906	for (file.getAtoms()) |atom_index| {
1907	const atom = file.getAtom(atom_index) orelse continue;
1908	if (!atom.isAlive()) continue;
1909	atom.out_n_sect = backlinks[atom.out_n_sect];
1910	}
1911	}
1912
1913	if (self.getInternalObject()) |object| {
1914	for (object.getAtoms()) |atom_index| {
1915	const atom = object.getAtom(atom_index) orelse continue;
1916	if (!atom.isAlive()) continue;
1917	atom.out_n_sect = backlinks[atom.out_n_sect];
1918	}
1919	}
1920	}
1921
1922	pub fn addAtomsToSections(self: *MachO) !void {
1923	const tracy = trace(@src());
1924	defer tracy.end();
1925
1926	const gpa = self.base.comp.gpa;
1927
1928	if (self.getZigObject()) |zo| {
1929	for (zo.getAtoms()) |atom_index| {
1930	const atom = zo.getAtom(atom_index) orelse continue;
1931	if (!atom.isAlive()) continue;
1932	if (self.isZigSection(atom.out_n_sect)) continue;
1933	const atoms = &self.sections.items(.atoms)[atom.out_n_sect];
1934	try atoms.append(gpa, .{ .index = atom_index, .file = zo.index });
1935	}
1936	}
1937	for (self.objects.items) |index| {
1938	const file = self.getFile(index).?;
1939	for (file.getAtoms()) |atom_index| {
1940	const atom = file.getAtom(atom_index) orelse continue;
1941	if (!atom.isAlive()) continue;
1942	const atoms = &self.sections.items(.atoms)[atom.out_n_sect];
1943	try atoms.append(gpa, .{ .index = atom_index, .file = index });
1944	}
1945	}
1946	if (self.getInternalObject()) |object| {
1947	for (object.getAtoms()) |atom_index| {
1948	const atom = object.getAtom(atom_index) orelse continue;
1949	if (!atom.isAlive()) continue;
1950	const atoms = &self.sections.items(.atoms)[atom.out_n_sect];
1951	try atoms.append(gpa, .{ .index = atom_index, .file = object.index });
1952	}
1953	}
1954	}
1955
1956	fn calcSectionSizes(self: *MachO) !void {
1957	const tracy = trace(@src());
1958	defer tracy.end();
1959
1960	const diags = &self.base.comp.link_diags;
1961	const cpu_arch = self.getTarget().cpu.arch;
1962
1963	if (self.data_sect_index) |idx| {
1964	const header = &self.sections.items(.header)[idx];
1965	header.size += @sizeOf(u64);
1966	header.@"align" = 3;
1967	}
1968
1969	{
1970	const slice = self.sections.slice();
1971	for (slice.items(.header), slice.items(.atoms), 0..) |header, atoms, i| {
1972	if (atoms.items.len == 0) continue;
1973	if (self.requiresThunks() and header.isCode()) continue;
1974	calcSectionSizeWorker(self, @as(u8, @intCast(i)));
1975	}
1976
1977	if (self.requiresThunks()) {
1978	for (slice.items(.header), slice.items(.atoms), 0..) |header, atoms, i| {
1979	if (!header.isCode()) continue;
1980	if (atoms.items.len == 0) continue;
1981	createThunksWorker(self, @as(u8, @intCast(i)));
1982	}
1983	}
1984
1985	// At this point, we can also calculate most of the symtab and data-in-code linkedit section sizes
1986	if (self.getZigObject()) |zo| {
1987	File.calcSymtabSize(zo.asFile(), self);
1988	}
1989	for (self.objects.items) |index| {
1990	File.calcSymtabSize(self.getFile(index).?, self);
1991	}
1992	for (self.dylibs.items) |index| {
1993	File.calcSymtabSize(self.getFile(index).?, self);
1994	}
1995	if (self.getInternalObject()) |obj| {
1996	File.calcSymtabSize(obj.asFile(), self);
1997	}
1998	}
1999
2000	if (diags.hasErrors()) return error.AlreadyReported;
2001
2002	try self.calcSymtabSize();
2003
2004	if (self.got_sect_index) |idx| {
2005	const header = &self.sections.items(.header)[idx];
2006	header.size = self.got.size();
2007	header.@"align" = 3;
2008	}
2009
2010	if (self.stubs_sect_index) |idx| {
2011	const header = &self.sections.items(.header)[idx];
2012	header.size = self.stubs.size(self);
2013	header.@"align" = switch (cpu_arch) {
2014	.x86_64 => 1,
2015	.aarch64 => 2,
2016	else => 0,
2017	};
2018	}
2019
2020	if (self.stubs_helper_sect_index) |idx| {
2021	const header = &self.sections.items(.header)[idx];
2022	header.size = self.stubs_helper.size(self);
2023	header.@"align" = 2;
2024	}
2025
2026	if (self.la_symbol_ptr_sect_index) |idx| {
2027	const header = &self.sections.items(.header)[idx];
2028	header.size = self.la_symbol_ptr.size(self);
2029	header.@"align" = 3;
2030	}
2031
2032	if (self.tlv_ptr_sect_index) |idx| {
2033	const header = &self.sections.items(.header)[idx];
2034	header.size = self.tlv_ptr.size();
2035	header.@"align" = 3;
2036	}
2037
2038	if (self.objc_stubs_sect_index) |idx| {
2039	const header = &self.sections.items(.header)[idx];
2040	header.size = self.objc_stubs.size(self);
2041	header.@"align" = switch (cpu_arch) {
2042	.x86_64 => 0,
2043	.aarch64 => 2,
2044	else => 0,
2045	};
2046	}
2047	}
2048
2049	fn calcSectionSizeWorker(self: *MachO, sect_id: u8) void {
2050	const tracy = trace(@src());
2051	defer tracy.end();
2052
2053	const diags = &self.base.comp.link_diags;
2054
2055	const doWork = struct {
2056	fn doWork(macho_file: *MachO, header: *macho.section_64, atoms: []const Ref) !void {
2057	for (atoms) |ref| {
2058	const atom = ref.getAtom(macho_file).?;
2059	const atom_alignment = atom.alignment.toByteUnits() orelse 1;
2060	const offset = mem.alignForward(u64, header.size, atom_alignment);
2061	const padding = offset - header.size;
2062	atom.value = offset;
2063	header.size += padding + atom.size;
2064	header.@"align" = @max(header.@"align", atom.alignment.toLog2Units());
2065	}
2066	}
2067	}.doWork;
2068	const slice = self.sections.slice();
2069	const header = &slice.items(.header)[sect_id];
2070	const atoms = slice.items(.atoms)[sect_id].items;
2071	doWork(self, header, atoms) catch |err| {
2072	try diags.addError("failed to calculate size of section '{s},{s}': {s}", .{
2073	header.segName(), header.sectName(), @errorName(err),
2074	});
2075	};
2076	}
2077
2078	fn createThunksWorker(self: *MachO, sect_id: u8) void {
2079	const tracy = trace(@src());
2080	defer tracy.end();
2081	const diags = &self.base.comp.link_diags;
2082	self.createThunks(sect_id) catch |err| {
2083	const header = self.sections.items(.header)[sect_id];
2084	diags.addError("failed to create thunks and calculate size of section '{s},{s}': {s}", .{
2085	header.segName(), header.sectName(), @errorName(err),
2086	});
2087	};
2088	}
2089
2090	fn generateUnwindInfo(self: *MachO) !void {
2091	const tracy = trace(@src());
2092	defer tracy.end();
2093
2094	const diags = &self.base.comp.link_diags;
2095
2096	if (self.eh_frame_sect_index) |index| {
2097	const sect = &self.sections.items(.header)[index];
2098	sect.size = try eh_frame.calcSize(self);
2099	sect.@"align" = 3;
2100	}
2101	if (self.unwind_info_sect_index) |index| {
2102	const sect = &self.sections.items(.header)[index];
2103	self.unwind_info.generate(self) catch |err| switch (err) {
2104	error.TooManyPersonalities => return diags.fail("too many personalities in unwind info", .{}),
2105	else => |e| return e,
2106	};
2107	sect.size = self.unwind_info.calcSize();
2108	sect.@"align" = 2;
2109	}
2110	}
2111
2112	fn initSegments(self: *MachO) !void {
2113	const gpa = self.base.comp.gpa;
2114	const slice = self.sections.slice();
2115
2116	// Add __PAGEZERO if required
2117	const pagezero_size = self.pagezero_size orelse default_pagezero_size;
2118	const aligned_pagezero_size = mem.alignBackward(u64, pagezero_size, self.getPageSize());
2119	if (!self.base.isDynLib() and aligned_pagezero_size > 0) {
2120	if (aligned_pagezero_size != pagezero_size) {
2121	// TODO convert into a warning
2122	log.warn("requested __PAGEZERO size (0x{x}) is not page aligned", .{pagezero_size});
2123	log.warn(" rounding down to 0x{x}", .{aligned_pagezero_size});
2124	}
2125	self.pagezero_seg_index = try self.addSegment("__PAGEZERO", .{ .vmsize = aligned_pagezero_size });
2126	}
2127
2128	// __TEXT segment is non-optional
2129	self.text_seg_index = try self.addSegment("__TEXT", .{ .prot = getSegmentProt("__TEXT") });
2130
2131	// Next, create segments required by sections
2132	for (slice.items(.header)) |header| {
2133	const segname = header.segName();
2134	if (self.getSegmentByName(segname) == null) {
2135	_ = try self.addSegment(segname, .{ .prot = getSegmentProt(segname) });
2136	}
2137	}
2138
2139	// Add __LINKEDIT
2140	self.linkedit_seg_index = try self.addSegment("__LINKEDIT", .{ .prot = getSegmentProt("__LINKEDIT") });
2141
2142	// Sort segments
2143	const Entry = struct {
2144	index: u8,
2145
2146	pub fn lessThan(macho_file: *MachO, lhs: @This(), rhs: @This()) bool {
2147	return segmentLessThan(
2148	{},
2149	macho_file.segments.items[lhs.index].segName(),
2150	macho_file.segments.items[rhs.index].segName(),
2151	);
2152	}
2153	};
2154
2155	var entries = try std.array_list.Managed(Entry).initCapacity(gpa, self.segments.items.len);
2156	defer entries.deinit();
2157	for (0..self.segments.items.len) |index| {
2158	entries.appendAssumeCapacity(.{ .index = @intCast(index) });
2159	}
2160
2161	mem.sort(Entry, entries.items, self, Entry.lessThan);
2162
2163	const backlinks = try gpa.alloc(u8, entries.items.len);
2164	defer gpa.free(backlinks);
2165	for (entries.items, 0..) |entry, i| {
2166	backlinks[entry.index] = @intCast(i);
2167	}
2168
2169	const segments = try self.segments.toOwnedSlice(gpa);
2170	defer gpa.free(segments);
2171
2172	try self.segments.ensureTotalCapacityPrecise(gpa, segments.len);
2173	for (entries.items) |sorted| {
2174	self.segments.appendAssumeCapacity(segments[sorted.index]);
2175	}
2176
2177	for (&[_]*?u8{
2178	&self.pagezero_seg_index,
2179	&self.text_seg_index,
2180	&self.linkedit_seg_index,
2181	&self.zig_text_seg_index,
2182	&self.zig_const_seg_index,
2183	&self.zig_data_seg_index,
2184	&self.zig_bss_seg_index,
2185	}) |maybe_index| {
2186	if (maybe_index.*) |*index| {
2187	index.* = backlinks[index.*];
2188	}
2189	}
2190
2191	// Attach sections to segments
2192	for (slice.items(.header), slice.items(.segment_id)) |header, *seg_id| {
2193	const segname = header.segName();
2194	const segment_id = self.getSegmentByName(segname) orelse blk: {
2195	const segment_id = @as(u8, @intCast(self.segments.items.len));
2196	const protection = getSegmentProt(segname);
2197	try self.segments.append(gpa, .{
2198	.cmdsize = @sizeOf(macho.segment_command_64),
2199	.segname = makeStaticString(segname),
2200	.maxprot = protection,
2201	.initprot = protection,
2202	});
2203	break :blk segment_id;
2204	};
2205	const segment = &self.segments.items[segment_id];
2206	segment.cmdsize += @sizeOf(macho.section_64);
2207	segment.nsects += 1;
2208	seg_id.* = segment_id;
2209	}
2210
2211	// Set __DATA_CONST as READ_ONLY
2212	if (self.getSegmentByName("__DATA_CONST")) |seg_id| {
2213	const seg = &self.segments.items[seg_id];
2214	seg.flags |= macho.SG_READ_ONLY;
2215	}
2216	}
2217
2218	fn allocateSections(self: *MachO) !void {
2219	const header_size = try load_commands.calcMinHeaderSize(self);
2220	self.header_size = header_size;
2221	var vmaddr: u64 = if (self.pagezero_seg_index) |index|
2222	self.segments.items[index].vmaddr + self.segments.items[index].vmsize
2223	else
2224	0;
2225	vmaddr += header_size;
2226	var fileoff = header_size;
2227	var prev_seg_id: u8 = if (self.pagezero_seg_index) |index| index + 1 else 0;
2228
2229	const page_size = self.getPageSize();
2230	const slice = self.sections.slice();
2231	const last_index = for (0..slice.items(.header).len) |i| {
2232	if (self.isZigSection(@intCast(i))) break i;
2233	} else slice.items(.header).len;
2234
2235	for (slice.items(.header)[0..last_index], slice.items(.segment_id)[0..last_index]) |*header, curr_seg_id| {
2236	if (prev_seg_id != curr_seg_id) {
2237	vmaddr = mem.alignForward(u64, vmaddr, page_size);
2238	fileoff = mem.alignForward(u32, fileoff, page_size);
2239	}
2240
2241	const alignment = try self.alignPow(header.@"align");
2242
2243	vmaddr = mem.alignForward(u64, vmaddr, alignment);
2244	header.addr = vmaddr;
2245	vmaddr += header.size;
2246
2247	if (!header.isZerofill()) {
2248	fileoff = mem.alignForward(u32, fileoff, alignment);
2249	header.offset = fileoff;
2250	fileoff += @intCast(header.size);
2251	}
2252
2253	prev_seg_id = curr_seg_id;
2254	}
2255
2256	fileoff = mem.alignForward(u32, fileoff, page_size);
2257	for (slice.items(.header)[last_index..], slice.items(.segment_id)[last_index..]) |*header, seg_id| {
2258	if (header.isZerofill()) continue;
2259	if (header.offset < fileoff) {
2260	const existing_size = header.size;
2261	header.size = 0;
2262
2263	// Must move the entire section.
2264	const new_offset = try self.findFreeSpace(existing_size, page_size);
2265
2266	log.debug("moving '{s},{s}' from 0x{x} to 0x{x}", .{
2267	header.segName(),
2268	header.sectName(),
2269	header.offset,
2270	new_offset,
2271	});
2272
2273	try self.copyRangeAllZeroOut(header.offset, new_offset, existing_size);
2274
2275	header.offset = @intCast(new_offset);
2276	header.size = existing_size;
2277	self.segments.items[seg_id].fileoff = new_offset;
2278	}
2279	}
2280	}
2281
2282	/// We allocate segments in a separate step to also consider segments that have no sections.
2283	fn allocateSegments(self: *MachO) void {
2284	const first_index = if (self.pagezero_seg_index) |index| index + 1 else 0;
2285	const last_index = for (0..self.segments.items.len) |i| {
2286	if (self.isZigSegment(@intCast(i))) break i;
2287	} else self.segments.items.len;
2288
2289	var vmaddr: u64 = if (self.pagezero_seg_index) |index|
2290	self.segments.items[index].vmaddr + self.segments.items[index].vmsize
2291	else
2292	0;
2293	var fileoff: u64 = 0;
2294
2295	const page_size = self.getPageSize();
2296	const slice = self.sections.slice();
2297
2298	var next_sect_id: u8 = 0;
2299	for (self.segments.items[first_index..last_index], first_index..last_index) |*seg, seg_id| {
2300	seg.vmaddr = vmaddr;
2301	seg.fileoff = fileoff;
2302
2303	while (next_sect_id < slice.items(.header).len) : (next_sect_id += 1) {
2304	const header = slice.items(.header)[next_sect_id];
2305	const sid = slice.items(.segment_id)[next_sect_id];
2306
2307	if (seg_id != sid) break;
2308
2309	vmaddr = header.addr + header.size;
2310	if (!header.isZerofill()) {
2311	fileoff = header.offset + header.size;
2312	}
2313	}
2314
2315	seg.vmsize = vmaddr - seg.vmaddr;
2316	seg.filesize = fileoff - seg.fileoff;
2317
2318	vmaddr = mem.alignForward(u64, vmaddr, page_size);
2319	fileoff = mem.alignForward(u64, fileoff, page_size);
2320	}
2321	}
2322
2323	fn allocateSyntheticSymbols(self: *MachO) void {
2324	if (self.getInternalObject()) |obj| {
2325	obj.allocateSyntheticSymbols(self);
2326
2327	const text_seg = self.getTextSegment();
2328
2329	for (obj.boundary_symbols.items) |sym_index| {
2330	const ref = obj.getSymbolRef(sym_index, self);
2331	const sym = ref.getSymbol(self).?;
2332	const name = sym.getName(self);
2333
2334	sym.value = text_seg.vmaddr;
2335
2336	if (mem.startsWith(u8, name, "segment$start$")) {
2337	const segname = name["segment$start$".len..];
2338	if (self.getSegmentByName(segname)) |seg_id| {
2339	const seg = self.segments.items[seg_id];
2340	sym.value = seg.vmaddr;
2341	}
2342	} else if (mem.startsWith(u8, name, "segment$end$")) {
2343	const segname = name["segment$end$".len..];
2344	if (self.getSegmentByName(segname)) |seg_id| {
2345	const seg = self.segments.items[seg_id];
2346	sym.value = seg.vmaddr + seg.vmsize;
2347	}
2348	} else if (mem.startsWith(u8, name, "section$start$")) {
2349	const actual_name = name["section$start$".len..];
2350	const sep = mem.findScalar(u8, actual_name, '$').?; // TODO error rather than a panic
2351	const segname = actual_name[0..sep];
2352	const sectname = actual_name[sep + 1 ..];
2353	if (self.getSectionByName(segname, sectname)) |sect_id| {
2354	const sect = self.sections.items(.header)[sect_id];
2355	sym.value = sect.addr;
2356	sym.out_n_sect = sect_id;
2357	}
2358	} else if (mem.startsWith(u8, name, "section$end$")) {
2359	const actual_name = name["section$end$".len..];
2360	const sep = mem.findScalar(u8, actual_name, '$').?; // TODO error rather than a panic
2361	const segname = actual_name[0..sep];
2362	const sectname = actual_name[sep + 1 ..];
2363	if (self.getSectionByName(segname, sectname)) |sect_id| {
2364	const sect = self.sections.items(.header)[sect_id];
2365	sym.value = sect.addr + sect.size;
2366	sym.out_n_sect = sect_id;
2367	}
2368	} else unreachable;
2369	}
2370
2371	if (self.objc_stubs.symbols.items.len > 0) {
2372	const addr = self.sections.items(.header)[self.objc_stubs_sect_index.?].addr;
2373
2374	for (self.objc_stubs.symbols.items, 0..) |ref, idx| {
2375	const sym = ref.getSymbol(self).?;
2376	sym.value = addr + idx * ObjcStubsSection.entrySize(self.getTarget().cpu.arch);
2377	sym.out_n_sect = self.objc_stubs_sect_index.?;
2378	}
2379	}
2380	}
2381	}
2382
2383	fn allocateLinkeditSegment(self: *MachO) !void {
2384	var fileoff: u64 = 0;
2385	var vmaddr: u64 = 0;
2386
2387	for (self.segments.items) |seg| {
2388	if (fileoff < seg.fileoff + seg.filesize) fileoff = seg.fileoff + seg.filesize;
2389	if (vmaddr < seg.vmaddr + seg.vmsize) vmaddr = seg.vmaddr + seg.vmsize;
2390	}
2391
2392	const page_size = self.getPageSize();
2393	const seg = self.getLinkeditSegment();
2394	seg.vmaddr = mem.alignForward(u64, vmaddr, page_size);
2395	seg.fileoff = mem.alignForward(u64, fileoff, page_size);
2396
2397	var off = try self.cast(u32, seg.fileoff);
2398	// DYLD_INFO_ONLY
2399	{
2400	const cmd = &self.dyld_info_cmd;
2401	cmd.rebase_off = off;
2402	off += cmd.rebase_size;
2403	cmd.bind_off = off;
2404	off += cmd.bind_size;
2405	cmd.weak_bind_off = off;
2406	off += cmd.weak_bind_size;
2407	cmd.lazy_bind_off = off;
2408	off += cmd.lazy_bind_size;
2409	cmd.export_off = off;
2410	off += cmd.export_size;
2411	off = mem.alignForward(u32, off, @alignOf(u64));
2412	}
2413
2414	// FUNCTION_STARTS
2415	{
2416	const cmd = &self.function_starts_cmd;
2417	cmd.dataoff = off;
2418	off += cmd.datasize;
2419	off = mem.alignForward(u32, off, @alignOf(u64));
2420	}
2421
2422	// DATA_IN_CODE
2423	{
2424	const cmd = &self.data_in_code_cmd;
2425	cmd.dataoff = off;
2426	off += cmd.datasize;
2427	off = mem.alignForward(u32, off, @alignOf(u64));
2428	}
2429
2430	// SYMTAB (symtab)
2431	{
2432	const cmd = &self.symtab_cmd;
2433	cmd.symoff = off;
2434	off += cmd.nsyms * @sizeOf(macho.nlist_64);
2435	off = mem.alignForward(u32, off, @alignOf(u32));
2436	}
2437
2438	// DYSYMTAB
2439	{
2440	const cmd = &self.dysymtab_cmd;
2441	cmd.indirectsymoff = off;
2442	off += cmd.nindirectsyms * @sizeOf(u32);
2443	off = mem.alignForward(u32, off, @alignOf(u64));
2444	}
2445
2446	// SYMTAB (strtab)
2447	{
2448	const cmd = &self.symtab_cmd;
2449	cmd.stroff = off;
2450	off += cmd.strsize;
2451	}
2452
2453	seg.filesize = off - seg.fileoff;
2454	}
2455
2456	fn resizeSections(self: *MachO) !void {
2457	const slice = self.sections.slice();
2458	for (slice.items(.header), slice.items(.out), 0..) |header, *out, n_sect| {
2459	if (header.isZerofill()) continue;
2460	if (self.isZigSection(@intCast(n_sect))) continue; // TODO this is horrible
2461	const cpu_arch = self.getTarget().cpu.arch;
2462	const size = try self.cast(usize, header.size);
2463	try out.resize(self.base.comp.gpa, size);
2464	const padding_byte: u8 = if (header.isCode() and cpu_arch == .x86_64) 0xcc else 0;
2465	@memset(out.items, padding_byte);
2466	}
2467	}
2468
2469	fn writeSectionsAndUpdateLinkeditSizes(self: *MachO) !void {
2470	const tracy = trace(@src());
2471	defer tracy.end();
2472
2473	const gpa = self.base.comp.gpa;
2474	const diags = &self.base.comp.link_diags;
2475
2476	const cmd = self.symtab_cmd;
2477	try self.symtab.resize(gpa, cmd.nsyms);
2478	try self.strtab.resize(gpa, cmd.strsize);
2479	self.strtab.items[0] = 0;
2480
2481	{
2482	for (self.objects.items) |index| {
2483	writeAtomsWorker(self, self.getFile(index).?);
2484	}
2485	if (self.getZigObject()) |zo| {
2486	writeAtomsWorker(self, zo.asFile());
2487	}
2488	if (self.getInternalObject()) |obj| {
2489	writeAtomsWorker(self, obj.asFile());
2490	}
2491	for (self.thunks.items) |thunk| {
2492	writeThunkWorker(self, thunk);
2493	}
2494
2495	const slice = self.sections.slice();
2496	for (&[_]?u8{
2497	self.eh_frame_sect_index,
2498	self.unwind_info_sect_index,
2499	self.got_sect_index,
2500	self.stubs_sect_index,
2501	self.la_symbol_ptr_sect_index,
2502	self.tlv_ptr_sect_index,
2503	self.objc_stubs_sect_index,
2504	}) |maybe_sect_id| {
2505	if (maybe_sect_id) |sect_id| {
2506	const out = slice.items(.out)[sect_id].items;
2507	writeSyntheticSectionWorker(self, sect_id, out);
2508	}
2509	}
2510
2511	if (self.la_symbol_ptr_sect_index) |_| {
2512	updateLazyBindSizeWorker(self);
2513	}
2514
2515	updateLinkeditSizeWorker(self, .rebase);
2516	updateLinkeditSizeWorker(self, .bind);
2517	updateLinkeditSizeWorker(self, .weak_bind);
2518	updateLinkeditSizeWorker(self, .export_trie);
2519	updateLinkeditSizeWorker(self, .data_in_code);
2520
2521	if (self.getZigObject()) |zo| {
2522	File.writeSymtab(zo.asFile(), self, self);
2523	}
2524	for (self.objects.items) |index| {
2525	File.writeSymtab(self.getFile(index).?, self, self);
2526	}
2527	for (self.dylibs.items) |index| {
2528	File.writeSymtab(self.getFile(index).?, self, self);
2529	}
2530	if (self.getInternalObject()) |obj| {
2531	File.writeSymtab(obj.asFile(), self, self);
2532	}
2533	if (self.requiresThunks()) for (self.thunks.items) |th| {
2534	Thunk.writeSymtab(th, self, self);
2535	};
2536	}
2537
2538	if (diags.hasErrors()) return error.AlreadyReported;
2539	}
2540
2541	fn writeAtomsWorker(self: *MachO, file: File) void {
2542	const tracy = trace(@src());
2543	defer tracy.end();
2544	file.writeAtoms(self) catch |err| {
2545	self.reportParseError2(file.getIndex(), "failed to resolve relocations and write atoms: {s}", .{
2546	@errorName(err),
2547	}) catch {};
2548	};
2549	}
2550
2551	fn writeThunkWorker(self: *MachO, thunk: Thunk) void {
2552	const tracy = trace(@src());
2553	defer tracy.end();
2554
2555	const diags = &self.base.comp.link_diags;
2556
2557	const doWork = struct {
2558	fn doWork(th: Thunk, buffer: []u8, macho_file: *MachO) !void {
2559	const off = try macho_file.cast(usize, th.value);
2560	const size = th.size();
2561	var stream: Writer = .fixed(buffer[off..][0..size]);
2562	try th.write(macho_file, &stream);
2563	}
2564	}.doWork;
2565	const out = self.sections.items(.out)[thunk.out_n_sect].items;
2566	doWork(thunk, out, self) catch |err| {
2567	diags.addError("failed to write contents of thunk: {s}", .{@errorName(err)});
2568	};
2569	}
2570
2571	fn writeSyntheticSectionWorker(self: *MachO, sect_id: u8, out: []u8) void {
2572	const tracy = trace(@src());
2573	defer tracy.end();
2574
2575	const diags = &self.base.comp.link_diags;
2576
2577	const Tag = enum {
2578	eh_frame,
2579	unwind_info,
2580	got,
2581	stubs,
2582	la_symbol_ptr,
2583	tlv_ptr,
2584	objc_stubs,
2585	};
2586
2587	const doWork = struct {
2588	fn doWork(macho_file: *MachO, tag: Tag, buffer: []u8) !void {
2589	var stream: Writer = .fixed(buffer);
2590	switch (tag) {
2591	.eh_frame => eh_frame.write(macho_file, buffer),
2592	.unwind_info => try macho_file.unwind_info.write(macho_file, buffer),
2593	.got => try macho_file.got.write(macho_file, &stream),
2594	.stubs => try macho_file.stubs.write(macho_file, &stream),
2595	.la_symbol_ptr => try macho_file.la_symbol_ptr.write(macho_file, &stream),
2596	.tlv_ptr => try macho_file.tlv_ptr.write(macho_file, &stream),
2597	.objc_stubs => try macho_file.objc_stubs.write(macho_file, &stream),
2598	}
2599	}
2600	}.doWork;
2601
2602	const header = self.sections.items(.header)[sect_id];
2603	const tag: Tag = tag: {
2604	if (self.eh_frame_sect_index != null and
2605	self.eh_frame_sect_index.? == sect_id) break :tag .eh_frame;
2606	if (self.unwind_info_sect_index != null and
2607	self.unwind_info_sect_index.? == sect_id) break :tag .unwind_info;
2608	if (self.got_sect_index != null and
2609	self.got_sect_index.? == sect_id) break :tag .got;
2610	if (self.stubs_sect_index != null and
2611	self.stubs_sect_index.? == sect_id) break :tag .stubs;
2612	if (self.la_symbol_ptr_sect_index != null and
2613	self.la_symbol_ptr_sect_index.? == sect_id) break :tag .la_symbol_ptr;
2614	if (self.tlv_ptr_sect_index != null and
2615	self.tlv_ptr_sect_index.? == sect_id) break :tag .tlv_ptr;
2616	if (self.objc_stubs_sect_index != null and
2617	self.objc_stubs_sect_index.? == sect_id) break :tag .objc_stubs;
2618	unreachable;
2619	};
2620	doWork(self, tag, out) catch |err| {
2621	diags.addError("could not write section '{s},{s}': {s}", .{
2622	header.segName(), header.sectName(), @errorName(err),
2623	});
2624	};
2625	}
2626
2627	fn updateLazyBindSizeWorker(self: *MachO) void {
2628	const tracy = trace(@src());
2629	defer tracy.end();
2630
2631	const diags = &self.base.comp.link_diags;
2632
2633	const doWork = struct {
2634	fn doWork(macho_file: *MachO) !void {
2635	try macho_file.lazy_bind_section.updateSize(macho_file);
2636	const sect_id = macho_file.stubs_helper_sect_index.?;
2637	const out = &macho_file.sections.items(.out)[sect_id];
2638	var stream: Writer = .fixed(out.items);
2639	try macho_file.stubs_helper.write(macho_file, &stream);
2640	}
2641	}.doWork;
2642	doWork(self) catch |err|
2643	diags.addError("could not calculate size of lazy binding section: {s}", .{@errorName(err)});
2644	}
2645
2646	pub fn updateLinkeditSizeWorker(self: *MachO, tag: enum {
2647	rebase,
2648	bind,
2649	weak_bind,
2650	export_trie,
2651	data_in_code,
2652	}) void {
2653	const diags = &self.base.comp.link_diags;
2654	const res = switch (tag) {
2655	.rebase => self.rebase_section.updateSize(self),
2656	.bind => self.bind_section.updateSize(self),
2657	.weak_bind => self.weak_bind_section.updateSize(self),
2658	.export_trie => self.export_trie.updateSize(self),
2659	.data_in_code => self.data_in_code.updateSize(self),
2660	};
2661	res catch |err|
2662	diags.addError("could not calculate size of {s} section: {s}", .{ @tagName(tag), @errorName(err) });
2663	}
2664
2665	fn writeSectionsToFile(self: *MachO) !void {
2666	const tracy = trace(@src());
2667	defer tracy.end();
2668
2669	const slice = self.sections.slice();
2670	for (slice.items(.header), slice.items(.out)) |header, out| {
2671	try self.pwriteAll(out.items, header.offset);
2672	}
2673	}
2674
2675	fn writeLinkeditSectionsToFile(self: *MachO) !void {
2676	const tracy = trace(@src());
2677	defer tracy.end();
2678	try self.writeDyldInfo();
2679	try self.writeDataInCode();
2680	try self.writeSymtabToFile();
2681	try self.writeIndsymtab();
2682	}
2683
2684	fn writeDyldInfo(self: *MachO) !void {
2685	const tracy = trace(@src());
2686	defer tracy.end();
2687
2688	const gpa = self.base.comp.gpa;
2689	const base_off = self.getLinkeditSegment().fileoff;
2690	const cmd = self.dyld_info_cmd;
2691	var needed_size: u32 = 0;
2692	needed_size += cmd.rebase_size;
2693	needed_size += cmd.bind_size;
2694	needed_size += cmd.weak_bind_size;
2695	needed_size += cmd.lazy_bind_size;
2696	needed_size += cmd.export_size;
2697
2698	const buffer = try gpa.alloc(u8, needed_size);
2699	defer gpa.free(buffer);
2700	@memset(buffer, 0);
2701
2702	var writer: Writer = .fixed(buffer);
2703
2704	try self.rebase_section.write(&writer);
2705	writer.end = @intCast(cmd.bind_off - base_off);
2706	try self.bind_section.write(&writer);
2707	writer.end = @intCast(cmd.weak_bind_off - base_off);
2708	try self.weak_bind_section.write(&writer);
2709	writer.end = @intCast(cmd.lazy_bind_off - base_off);
2710	try self.lazy_bind_section.write(&writer);
2711	writer.end = @intCast(cmd.export_off - base_off);
2712	try self.export_trie.write(&writer);
2713	try self.pwriteAll(buffer, cmd.rebase_off);
2714	}
2715
2716	pub fn writeDataInCode(self: *MachO) !void {
2717	const tracy = trace(@src());
2718	defer tracy.end();
2719	const gpa = self.base.comp.gpa;
2720	const cmd = self.data_in_code_cmd;
2721	var buffer = try std.Io.Writer.Allocating.initCapacity(gpa, self.data_in_code.size());
2722	defer buffer.deinit();
2723	self.data_in_code.write(self, &buffer.writer) catch return error.OutOfMemory;
2724	try self.pwriteAll(buffer.written(), cmd.dataoff);
2725	}
2726
2727	fn writeIndsymtab(self: *MachO) !void {
2728	const tracy = trace(@src());
2729	defer tracy.end();
2730	const gpa = self.base.comp.gpa;
2731	const cmd = self.dysymtab_cmd;
2732	const needed_size = cmd.nindirectsyms * @sizeOf(u32);
2733	const buffer = try gpa.alloc(u8, needed_size);
2734	defer gpa.free(buffer);
2735	var writer: Writer = .fixed(buffer);
2736	try self.indsymtab.write(self, &writer);
2737	try self.pwriteAll(buffer, cmd.indirectsymoff);
2738	}
2739
2740	pub fn writeSymtabToFile(self: *MachO) !void {
2741	const tracy = trace(@src());
2742	defer tracy.end();
2743	const cmd = self.symtab_cmd;
2744	try self.pwriteAll(@ptrCast(self.symtab.items), cmd.symoff);
2745	try self.pwriteAll(self.strtab.items, cmd.stroff);
2746	}
2747
2748	fn writeUnwindInfo(self: *MachO) !void {
2749	const tracy = trace(@src());
2750	defer tracy.end();
2751
2752	const gpa = self.base.comp.gpa;
2753
2754	if (self.eh_frame_sect_index) |index| {
2755	const header = self.sections.items(.header)[index];
2756	const size = try self.cast(usize, header.size);
2757	const buffer = try gpa.alloc(u8, size);
2758	defer gpa.free(buffer);
2759	eh_frame.write(self, buffer);
2760	try self.pwriteAll(buffer, header.offset);
2761	}
2762
2763	if (self.unwind_info_sect_index) |index| {
2764	const header = self.sections.items(.header)[index];
2765	const size = try self.cast(usize, header.size);
2766	const buffer = try gpa.alloc(u8, size);
2767	defer gpa.free(buffer);
2768	try self.unwind_info.write(self, buffer);
2769	try self.pwriteAll(buffer, header.offset);
2770	}
2771	}
2772
2773	fn calcSymtabSize(self: *MachO) !void {
2774	const tracy = trace(@src());
2775	defer tracy.end();
2776
2777	const gpa = self.base.comp.gpa;
2778
2779	var files = std.array_list.Managed(File.Index).init(gpa);
2780	defer files.deinit();
2781	try files.ensureTotalCapacityPrecise(self.objects.items.len + self.dylibs.items.len + 2);
2782	if (self.zig_object) |index| files.appendAssumeCapacity(index);
2783	for (self.objects.items) |index| files.appendAssumeCapacity(index);
2784	for (self.dylibs.items) |index| files.appendAssumeCapacity(index);
2785	if (self.internal_object) |index| files.appendAssumeCapacity(index);
2786
2787	var nlocals: u32 = 0;
2788	var nstabs: u32 = 0;
2789	var nexports: u32 = 0;
2790	var nimports: u32 = 0;
2791	var strsize: u32 = 1;
2792
2793	if (self.requiresThunks()) for (self.thunks.items) |*th| {
2794	th.output_symtab_ctx.ilocal = nlocals;
2795	th.output_symtab_ctx.stroff = strsize;
2796	th.calcSymtabSize(self);
2797	nlocals += th.output_symtab_ctx.nlocals;
2798	strsize += th.output_symtab_ctx.strsize;
2799	};
2800
2801	for (files.items) |index| {
2802	const file = self.getFile(index).?;
2803	const ctx = switch (file) {
2804	inline else => |x| &x.output_symtab_ctx,
2805	};
2806	ctx.ilocal = nlocals;
2807	ctx.istab = nstabs;
2808	ctx.iexport = nexports;
2809	ctx.iimport = nimports;
2810	ctx.stroff = strsize;
2811	nlocals += ctx.nlocals;
2812	nstabs += ctx.nstabs;
2813	nexports += ctx.nexports;
2814	nimports += ctx.nimports;
2815	strsize += ctx.strsize;
2816	}
2817
2818	for (files.items) |index| {
2819	const file = self.getFile(index).?;
2820	const ctx = switch (file) {
2821	inline else => |x| &x.output_symtab_ctx,
2822	};
2823	ctx.istab += nlocals;
2824	ctx.iexport += nlocals + nstabs;
2825	ctx.iimport += nlocals + nstabs + nexports;
2826	}
2827
2828	try self.indsymtab.updateSize(self);
2829
2830	{
2831	const cmd = &self.symtab_cmd;
2832	cmd.nsyms = nlocals + nstabs + nexports + nimports;
2833	cmd.strsize = strsize;
2834	}
2835
2836	{
2837	const cmd = &self.dysymtab_cmd;
2838	cmd.ilocalsym = 0;
2839	cmd.nlocalsym = nlocals + nstabs;
2840	cmd.iextdefsym = nlocals + nstabs;
2841	cmd.nextdefsym = nexports;
2842	cmd.iundefsym = nlocals + nstabs + nexports;
2843	cmd.nundefsym = nimports;
2844	}
2845	}
2846
2847	fn writeLoadCommands(self: *MachO) !struct { usize, usize, u64 } {
2848	const comp = self.base.comp;
2849	const gpa = comp.gpa;
2850	const needed_size = try load_commands.calcLoadCommandsSize(self, false);
2851	const buffer = try gpa.alloc(u8, needed_size);
2852	defer gpa.free(buffer);
2853
2854	var writer: Writer = .fixed(buffer);
2855
2856	var ncmds: usize = 0;
2857
2858	// Segment and section load commands
2859	{
2860	const slice = self.sections.slice();
2861	var sect_id: usize = 0;
2862	for (self.segments.items) |seg| {
2863	try writer.writeStruct(seg, .little);
2864	for (slice.items(.header)[sect_id..][0..seg.nsects]) |header| {
2865	try writer.writeStruct(header, .little);
2866	}
2867	sect_id += seg.nsects;
2868	}
2869	ncmds += self.segments.items.len;
2870	}
2871
2872	try writer.writeStruct(self.dyld_info_cmd, .little);
2873	ncmds += 1;
2874	try writer.writeStruct(self.function_starts_cmd, .little);
2875	ncmds += 1;
2876	try writer.writeStruct(self.data_in_code_cmd, .little);
2877	ncmds += 1;
2878	try writer.writeStruct(self.symtab_cmd, .little);
2879	ncmds += 1;
2880	try writer.writeStruct(self.dysymtab_cmd, .little);
2881	ncmds += 1;
2882	try load_commands.writeDylinkerLC(&writer);
2883	ncmds += 1;
2884
2885	if (self.getInternalObject()) |obj| {
2886	if (obj.getEntryRef(self)) |ref| {
2887	const sym = ref.getSymbol(self).?;
2888	const seg = self.getTextSegment();
2889	const entryoff: u32 = if (sym.getFile(self) == null)
2890	0
2891	else
2892	@as(u32, @intCast(sym.getAddress(.{ .stubs = true }, self) - seg.vmaddr));
2893	try writer.writeStruct(@as(macho.entry_point_command, .{
2894	.entryoff = entryoff,
2895	.stacksize = self.base.stack_size,
2896	}), .little);
2897	ncmds += 1;
2898	}
2899	}
2900
2901	if (self.base.isDynLib()) {
2902	try load_commands.writeDylibIdLC(self, &writer);
2903	ncmds += 1;
2904	}
2905
2906	if (self.needsEncryptionInfo()) {
2907	try load_commands.writeEncryptionInfoLC(self, &writer);
2908	ncmds += 1;
2909	}
2910
2911	for (self.rpath_list) |rpath| {
2912	try load_commands.writeRpathLC(rpath, &writer);
2913	ncmds += 1;
2914	}
2915	if (comp.config.any_sanitize_thread) {
2916	const path = try comp.tsan_lib.?.full_object_path.toString(gpa);
2917	defer gpa.free(path);
2918	const rpath = std.fs.path.dirname(path) orelse ".";
2919	try load_commands.writeRpathLC(rpath, &writer);
2920	ncmds += 1;
2921	}
2922
2923	try writer.writeStruct(@as(macho.source_version_command, .{ .version = 0 }), .little);
2924	ncmds += 1;
2925
2926	if (self.platform.isBuildVersionCompatible()) {
2927	try load_commands.writeBuildVersionLC(self.platform, self.sdk_version, &writer);
2928	ncmds += 1;
2929	} else {
2930	try load_commands.writeVersionMinLC(self.platform, self.sdk_version, &writer);
2931	ncmds += 1;
2932	}
2933
2934	const uuid_cmd_offset = @sizeOf(macho.mach_header_64) + writer.end;
2935	try writer.writeStruct(self.uuid_cmd, .little);
2936	ncmds += 1;
2937
2938	for (self.dylibs.items) |index| {
2939	const dylib = self.getFile(index).?.dylib;
2940	assert(dylib.isAlive(self));
2941	const dylib_id = dylib.id.?;
2942	try load_commands.writeDylibLC(.{
2943	.cmd = if (dylib.weak)
2944	.LOAD_WEAK_DYLIB
2945	else if (dylib.reexport)
2946	.REEXPORT_DYLIB
2947	else
2948	.LOAD_DYLIB,
2949	.name = dylib_id.name,
2950	.timestamp = dylib_id.timestamp,
2951	.current_version = dylib_id.current_version,
2952	.compatibility_version = dylib_id.compatibility_version,
2953	}, &writer);
2954	ncmds += 1;
2955	}
2956
2957	if (self.requiresCodeSig()) {
2958	try writer.writeStruct(self.codesig_cmd, .little);
2959	ncmds += 1;
2960	}
2961
2962	assert(writer.end == needed_size);
2963
2964	try self.pwriteAll(buffer, @sizeOf(macho.mach_header_64));
2965
2966	return .{ ncmds, buffer.len, uuid_cmd_offset };
2967	}
2968
2969	fn writeHeader(self: *MachO, ncmds: usize, sizeofcmds: usize) !void {
2970	var header: macho.mach_header_64 = .{};
2971	header.flags = macho.MH_DYLDLINK;
2972
2973	// Only set MH_NOUNDEFS if we're not allowing undefined symbols via dynamic lookup.
2974	// When dynamic_lookup is enabled, undefined symbols are resolved at runtime by dyld.
2975	if (self.undefined_treatment != .dynamic_lookup) {
2976	header.flags |= macho.MH_NOUNDEFS;
2977	}
2978
2979	// TODO: if (self.options.namespace == .two_level) {
2980	header.flags |= macho.MH_TWOLEVEL;
2981	// }
2982
2983	switch (self.getTarget().cpu.arch) {
2984	.aarch64 => {
2985	header.cputype = macho.CPU_TYPE_ARM64;
2986	header.cpusubtype = macho.CPU_SUBTYPE_ARM_ALL;
2987	},
2988	.x86_64 => {
2989	header.cputype = macho.CPU_TYPE_X86_64;
2990	header.cpusubtype = macho.CPU_SUBTYPE_X86_64_ALL;
2991	},
2992	else => {},
2993	}
2994
2995	if (self.base.isDynLib()) {
2996	header.filetype = macho.MH_DYLIB;
2997	} else {
2998	header.filetype = macho.MH_EXECUTE;
2999	header.flags |= macho.MH_PIE;
3000	}
3001
3002	const has_reexports = for (self.dylibs.items) |index| {
3003	if (self.getFile(index).?.dylib.reexport) break true;
3004	} else false;
3005	if (!has_reexports) {
3006	header.flags |= macho.MH_NO_REEXPORTED_DYLIBS;
3007	}
3008
3009	if (self.has_tlv.load(.seq_cst)) {
3010	header.flags |= macho.MH_HAS_TLV_DESCRIPTORS;
3011	}
3012	if (self.binds_to_weak.load(.seq_cst)) {
3013	header.flags |= macho.MH_BINDS_TO_WEAK;
3014	}
3015	if (self.weak_defines.load(.seq_cst)) {
3016	header.flags |= macho.MH_WEAK_DEFINES;
3017	}
3018
3019	header.ncmds = @intCast(ncmds);
3020	header.sizeofcmds = @intCast(sizeofcmds);
3021
3022	log.debug("writing Mach-O header {}", .{header});
3023
3024	try self.pwriteAll(mem.asBytes(&header), 0);
3025	}
3026
3027	fn writeUuid(self: *MachO, uuid_cmd_offset: u64, has_codesig: bool) !void {
3028	const file_size = if (!has_codesig) blk: {
3029	const seg = self.getLinkeditSegment();
3030	break :blk seg.fileoff + seg.filesize;
3031	} else self.codesig_cmd.dataoff;
3032	try calcUuid(self.base.comp, self.base.file.?, file_size, &self.uuid_cmd.uuid);
3033	const offset = uuid_cmd_offset + @sizeOf(macho.load_command);
3034	try self.pwriteAll(&self.uuid_cmd.uuid, offset);
3035	}
3036
3037	pub fn writeCodeSignaturePadding(self: *MachO, code_sig: *CodeSignature) !void {
3038	const seg = self.getLinkeditSegment();
3039	// Code signature data has to be 16-bytes aligned for Apple tools to recognize the file
3040	// https://github.com/opensource-apple/cctools/blob/fdb4825f303fd5c0751be524babd32958181b3ed/libstuff/checkout.c#L271
3041	const offset = mem.alignForward(u64, seg.fileoff + seg.filesize, 16);
3042	const needed_size = code_sig.estimateSize(offset);
3043	seg.filesize = offset + needed_size - seg.fileoff;
3044	seg.vmsize = mem.alignForward(u64, seg.filesize, self.getPageSize());
3045	log.debug("writing code signature padding from 0x{x} to 0x{x}", .{ offset, offset + needed_size });
3046	// Pad out the space. We need to do this to calculate valid hashes for everything in the file
3047	// except for code signature data.
3048	try self.pwriteAll(&[_]u8{0}, offset + needed_size - 1);
3049
3050	self.codesig_cmd.dataoff = @as(u32, @intCast(offset));
3051	self.codesig_cmd.datasize = @as(u32, @intCast(needed_size));
3052	}
3053
3054	pub fn writeCodeSignature(self: *MachO, code_sig: *CodeSignature) !void {
3055	const seg = self.getTextSegment();
3056	const offset = self.codesig_cmd.dataoff;
3057	const gpa = self.base.comp.gpa;
3058
3059	var buffer: std.Io.Writer.Allocating = .init(gpa);
3060	defer buffer.deinit();
3061	// The writeAdhocSignature function internally changes code_sig.size()
3062	// during the execution.
3063	try buffer.ensureUnusedCapacity(code_sig.size());
3064
3065	code_sig.writeAdhocSignature(self, .{
3066	.file = self.base.file.?,
3067	.exec_seg_base = seg.fileoff,
3068	.exec_seg_limit = seg.filesize,
3069	.file_size = offset,
3070	.dylib = self.base.isDynLib(),
3071	}, &buffer.writer) catch |err| switch (err) {
3072	error.WriteFailed => return error.OutOfMemory,
3073	else => |e| return e,
3074	};
3075	assert(buffer.written().len == code_sig.size());
3076
3077	log.debug("writing code signature from 0x{x} to 0x{x}", .{
3078	offset,
3079	offset + buffer.written().len,
3080	});
3081
3082	try self.pwriteAll(buffer.written(), offset);
3083	}
3084
3085	pub fn updateFunc(
3086	self: *MachO,
3087	pt: Zcu.PerThread,
3088	func_index: InternPool.Index,
3089	mir: *const codegen.AnyMir,
3090	) link.Error!void {
3091	return self.getZigObject().?.updateFunc(self, pt, func_index, mir);
3092	}
3093
3094	pub fn updateNav(self: *MachO, pt: Zcu.PerThread, nav: InternPool.Nav.Index) link.Error!void {
3095	return self.getZigObject().?.updateNav(self, pt, nav);
3096	}
3097
3098	pub fn updateLineNumber(self: *MachO, pt: Zcu.PerThread, inst: InternPool.TrackedInst.Index, line: u32) link.Error!void {
3099	return self.getZigObject().?.updateLineNumber(pt, inst, line);
3100	}
3101
3102	pub fn updateExports(
3103	self: *MachO,
3104	pt: Zcu.PerThread,
3105	export_indices: []const Zcu.Export.Index,
3106	) link.Error!void {
3107	return self.getZigObject().?.updateExports(self, pt, export_indices);
3108	}
3109
3110	pub fn freeNav(self: *MachO, nav: InternPool.Nav.Index) void {
3111	return self.getZigObject().?.freeNav(nav);
3112	}
3113
3114	pub fn getNavVAddr(self: *MachO, pt: Zcu.PerThread, nav_index: InternPool.Nav.Index, reloc_info: link.File.RelocInfo) !u64 {
3115	return self.getZigObject().?.getNavVAddr(self, pt, nav_index, reloc_info);
3116	}
3117
3118	pub fn lowerUav(
3119	self: *MachO,
3120	pt: Zcu.PerThread,
3121	uav: InternPool.Index,
3122	explicit_alignment: InternPool.Alignment,
3123	) !link.File.SymbolId {
3124	return self.getZigObject().?.lowerUav(self, pt, uav, explicit_alignment);
3125	}
3126
3127	pub fn getUavVAddr(self: *MachO, uav: InternPool.Index, reloc_info: link.File.RelocInfo) !u64 {
3128	return self.getZigObject().?.getUavVAddr(self, uav, reloc_info);
3129	}
3130
3131	pub fn getGlobalSymbol(self: *MachO, name: []const u8, lib_name: ?[]const u8) !u32 {
3132	return self.getZigObject().?.getGlobalSymbol(self, name, lib_name);
3133	}
3134
3135	pub fn padToIdeal(actual_size: anytype) @TypeOf(actual_size) {
3136	return actual_size +| (actual_size / ideal_factor);
3137	}
3138
3139	fn detectAllocCollision(self: *MachO, start: u64, size: u64) !?u64 {
3140	// Conservatively commit one page size as reserved space for the headers as we
3141	// expect it to grow and everything else be moved in flush anyhow.
3142	const header_size = self.getPageSize();
3143	if (start < header_size)
3144	return header_size;
3145
3146	var at_end = true;
3147	const end = start + padToIdeal(size);
3148
3149	for (self.sections.items(.header)) |header| {
3150	if (header.isZerofill()) continue;
3151	const increased_size = padToIdeal(header.size);
3152	const test_end = header.offset +| increased_size;
3153	if (start < test_end) {
3154	if (end > header.offset) return test_end;
3155	if (test_end < std.math.maxInt(u64)) at_end = false;
3156	}
3157	}
3158
3159	for (self.segments.items) |seg| {
3160	const increased_size = padToIdeal(seg.filesize);
3161	const test_end = seg.fileoff +| increased_size;
3162	if (start < test_end) {
3163	if (end > seg.fileoff) return test_end;
3164	if (test_end < std.math.maxInt(u64)) at_end = false;
3165	}
3166	}
3167
3168	const comp = self.base.comp;
3169	const io = comp.io;
3170	if (at_end) try self.base.file.?.setLength(io, end);
3171	return null;
3172	}
3173
3174	fn detectAllocCollisionVirtual(self: *MachO, start: u64, size: u64) ?u64 {
3175	// Conservatively commit one page size as reserved space for the headers as we
3176	// expect it to grow and everything else be moved in flush anyhow.
3177	const header_size = self.getPageSize();
3178	if (start < header_size)
3179	return header_size;
3180
3181	const end = start + padToIdeal(size);
3182
3183	for (self.sections.items(.header)) |header| {
3184	const increased_size = padToIdeal(header.size);
3185	const test_end = header.addr +| increased_size;
3186	if (end > header.addr and start < test_end) {
3187	return test_end;
3188	}
3189	}
3190
3191	for (self.segments.items) |seg| {
3192	const increased_size = padToIdeal(seg.vmsize);
3193	const test_end = seg.vmaddr +| increased_size;
3194	if (end > seg.vmaddr and start < test_end) {
3195	return test_end;
3196	}
3197	}
3198
3199	return null;
3200	}
3201
3202	pub fn allocatedSize(self: *MachO, start: u64) u64 {
3203	if (start == 0) return 0;
3204
3205	var min_pos: u64 = std.math.maxInt(u64);
3206
3207	for (self.sections.items(.header)) |header| {
3208	if (header.offset <= start) continue;
3209	if (header.offset < min_pos) min_pos = header.offset;
3210	}
3211
3212	for (self.segments.items) |seg| {
3213	if (seg.fileoff <= start) continue;
3214	if (seg.fileoff < min_pos) min_pos = seg.fileoff;
3215	}
3216
3217	return min_pos - start;
3218	}
3219
3220	pub fn allocatedSizeVirtual(self: *MachO, start: u64) u64 {
3221	if (start == 0) return 0;
3222
3223	var min_pos: u64 = std.math.maxInt(u64);
3224
3225	for (self.sections.items(.header)) |header| {
3226	if (header.addr <= start) continue;
3227	if (header.addr < min_pos) min_pos = header.addr;
3228	}
3229
3230	for (self.segments.items) |seg| {
3231	if (seg.vmaddr <= start) continue;
3232	if (seg.vmaddr < min_pos) min_pos = seg.vmaddr;
3233	}
3234
3235	return min_pos - start;
3236	}
3237
3238	pub fn findFreeSpace(self: *MachO, object_size: u64, min_alignment: u32) !u64 {
3239	var start: u64 = 0;
3240	while (try self.detectAllocCollision(start, object_size)) |item_end| {
3241	start = mem.alignForward(u64, item_end, min_alignment);
3242	}
3243	return start;
3244	}
3245
3246	pub fn findFreeSpaceVirtual(self: *MachO, object_size: u64, min_alignment: u32) u64 {
3247	var start: u64 = 0;
3248	while (self.detectAllocCollisionVirtual(start, object_size)) |item_end| {
3249	start = mem.alignForward(u64, item_end, min_alignment);
3250	}
3251	return start;
3252	}
3253
3254	pub fn copyRangeAll(self: *MachO, old_offset: u64, new_offset: u64, size: u64) !void {
3255	return self.base.copyRangeAll(old_offset, new_offset, size);
3256	}
3257
3258	/// Like copyRangeAll but also ensures the source region is zeroed out after copy.
3259	/// This is so that we guarantee zeroed out regions for mapping of zerofill sections by the loader.
3260	fn copyRangeAllZeroOut(self: *MachO, old_offset: u64, new_offset: u64, size: u64) !void {
3261	const comp = self.base.comp;
3262	const io = comp.io;
3263	const file = self.base.file.?;
3264	var write_buffer: [2048]u8 = undefined;
3265	var file_reader = file.reader(io, &.{});
3266	file_reader.pos = old_offset;
3267	var file_writer = file.writer(io, &write_buffer);
3268	file_writer.pos = new_offset;
3269	const size_u = math.cast(usize, size) orelse return error.Overflow;
3270	const n = file_writer.interface.sendFileAll(&file_reader, .limited(size_u)) catch |err| switch (err) {
3271	error.ReadFailed => switch (file_reader.err.?) {
3272	error.ConnectionResetByPeer => return error.Unexpected, // not a socket
3273	error.SocketUnconnected => return error.Unexpected, // not a socket
3274	else => |e| return e,
3275	},
3276	error.WriteFailed => return file_writer.err.?,
3277	};
3278	assert(n == size_u);
3279	file_writer.seekTo(old_offset) catch |err| switch (err) {
3280	error.WriteFailed => return file_writer.err.?,
3281	else => |e| return e,
3282	};
3283	file_writer.interface.splatByteAll(0, size_u) catch |err| switch (err) {
3284	error.WriteFailed => return file_writer.err.?,
3285	};
3286	file_writer.interface.flush() catch |err| switch (err) {
3287	error.WriteFailed => return file_writer.err.?,
3288	};
3289	}
3290
3291	const InitMetadataOptions = struct {
3292	emit: Path,
3293	zo: *ZigObject,
3294	symbol_count_hint: u64,
3295	program_code_size_hint: u64,
3296	};
3297
3298	pub fn closeDebugInfo(self: *MachO) bool {
3299	const comp = self.base.comp;
3300	const io = comp.io;
3301	const d_sym = &(self.d_sym orelse return false);
3302	d_sym.file.?.close(io);
3303	d_sym.file = null;
3304	return true;
3305	}
3306
3307	pub fn reopenDebugInfo(self: *MachO) !void {
3308	assert(self.d_sym.?.file == null);
3309
3310	assert(!self.base.comp.config.use_llvm);
3311	assert(self.base.comp.config.debug_format == .dwarf);
3312
3313	const comp = self.base.comp;
3314	const io = comp.io;
3315	const gpa = comp.gpa;
3316	const sep = fs.path.sep_str;
3317	const d_sym_path = try std.fmt.allocPrint(
3318	gpa,
3319	"{s}.dSYM" ++ sep ++ "Contents" ++ sep ++ "Resources" ++ sep ++ "DWARF",
3320	.{self.base.emit.sub_path},
3321	);
3322	defer gpa.free(d_sym_path);
3323
3324	var d_sym_bundle = try self.base.emit.root_dir.handle.createDirPathOpen(io, d_sym_path, .{});
3325	defer d_sym_bundle.close(io);
3326
3327	self.d_sym.?.file = try d_sym_bundle.createFile(io, fs.path.basename(self.base.emit.sub_path), .{
3328	.truncate = false,
3329	.read = true,
3330	});
3331	}
3332
3333	// TODO: move to ZigObject
3334	fn initMetadata(self: *MachO, options: InitMetadataOptions) !void {
3335	const comp = self.base.comp;
3336	const gpa = comp.gpa;
3337	const io = comp.io;
3338
3339	if (!self.base.isRelocatable()) {
3340	const base_vmaddr = blk: {
3341	const pagezero_size = self.pagezero_size orelse default_pagezero_size;
3342	break :blk mem.alignBackward(u64, pagezero_size, self.getPageSize());
3343	};
3344
3345	{
3346	const filesize = options.program_code_size_hint;
3347	const off = try self.findFreeSpace(filesize, self.getPageSize());
3348	self.zig_text_seg_index = try self.addSegment("__TEXT_ZIG", .{
3349	.fileoff = off,
3350	.filesize = filesize,
3351	.vmaddr = base_vmaddr + 0x4000000,
3352	.vmsize = filesize,
3353	.prot = .{ .READ = true, .EXEC = true },
3354	});
3355	}
3356
3357	{
3358	const filesize: u64 = 1024;
3359	const off = try self.findFreeSpace(filesize, self.getPageSize());
3360	self.zig_const_seg_index = try self.addSegment("__CONST_ZIG", .{
3361	.fileoff = off,
3362	.filesize = filesize,
3363	.vmaddr = base_vmaddr + 0xc000000,
3364	.vmsize = filesize,
3365	.prot = .{ .READ = true, .WRITE = true },
3366	});
3367	}
3368
3369	{
3370	const filesize: u64 = 1024;
3371	const off = try self.findFreeSpace(filesize, self.getPageSize());
3372	self.zig_data_seg_index = try self.addSegment("__DATA_ZIG", .{
3373	.fileoff = off,
3374	.filesize = filesize,
3375	.vmaddr = base_vmaddr + 0x10000000,
3376	.vmsize = filesize,
3377	.prot = .{ .READ = true, .WRITE = true },
3378	});
3379	}
3380
3381	{
3382	const memsize: u64 = 1024;
3383	self.zig_bss_seg_index = try self.addSegment("__BSS_ZIG", .{
3384	.vmaddr = base_vmaddr + 0x14000000,
3385	.vmsize = memsize,
3386	.prot = .{ .READ = true, .WRITE = true },
3387	});
3388	}
3389
3390	if (options.zo.dwarf) |*dwarf| {
3391	// Create dSYM bundle.
3392	log.debug("creating {s}.dSYM bundle", .{options.emit.sub_path});
3393	self.d_sym = .{
3394	.io = io,
3395	.allocator = gpa,
3396	.file = null,
3397	};
3398	try self.reopenDebugInfo();
3399	try self.d_sym.?.initMetadata(self);
3400	try dwarf.initMetadata();
3401	}
3402	}
3403
3404	const appendSect = struct {
3405	fn appendSect(macho_file: *MachO, sect_id: u8, seg_id: u8) void {
3406	const sect = &macho_file.sections.items(.header)[sect_id];
3407	const seg = macho_file.segments.items[seg_id];
3408	sect.addr = seg.vmaddr;
3409	sect.offset = @intCast(seg.fileoff);
3410	sect.size = seg.vmsize;
3411	macho_file.sections.items(.segment_id)[sect_id] = seg_id;
3412	}
3413	}.appendSect;
3414
3415	const allocSect = struct {
3416	fn allocSect(macho_file: *MachO, sect_id: u8, size: u64) !void {
3417	const sect = &macho_file.sections.items(.header)[sect_id];
3418	const alignment = try macho_file.alignPow(sect.@"align");
3419	if (!sect.isZerofill()) {
3420	sect.offset = try macho_file.cast(u32, try macho_file.findFreeSpace(size, alignment));
3421	}
3422	sect.addr = macho_file.findFreeSpaceVirtual(size, alignment);
3423	sect.size = size;
3424	}
3425	}.allocSect;
3426
3427	{
3428	self.zig_text_sect_index = try self.addSection("__TEXT_ZIG", "__text_zig", .{
3429	.alignment = switch (self.getTarget().cpu.arch) {
3430	.aarch64 => 2,
3431	.x86_64 => 0,
3432	else => unreachable,
3433	},
3434	.flags = macho.S_REGULAR | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS,
3435	});
3436	if (self.base.isRelocatable()) {
3437	try allocSect(self, self.zig_text_sect_index.?, options.program_code_size_hint);
3438	} else {
3439	appendSect(self, self.zig_text_sect_index.?, self.zig_text_seg_index.?);
3440	}
3441	}
3442
3443	{
3444	self.zig_const_sect_index = try self.addSection("__CONST_ZIG", "__const_zig", .{});
3445	if (self.base.isRelocatable()) {
3446	try allocSect(self, self.zig_const_sect_index.?, 1024);
3447	} else {
3448	appendSect(self, self.zig_const_sect_index.?, self.zig_const_seg_index.?);
3449	}
3450	}
3451
3452	{
3453	self.zig_data_sect_index = try self.addSection("__DATA_ZIG", "__data_zig", .{});
3454	if (self.base.isRelocatable()) {
3455	try allocSect(self, self.zig_data_sect_index.?, 1024);
3456	} else {
3457	appendSect(self, self.zig_data_sect_index.?, self.zig_data_seg_index.?);
3458	}
3459	}
3460
3461	{
3462	self.zig_bss_sect_index = try self.addSection("__BSS_ZIG", "__bss_zig", .{
3463	.flags = macho.S_ZEROFILL,
3464	});
3465	if (self.base.isRelocatable()) {
3466	try allocSect(self, self.zig_bss_sect_index.?, 1024);
3467	} else {
3468	appendSect(self, self.zig_bss_sect_index.?, self.zig_bss_seg_index.?);
3469	}
3470	}
3471
3472	if (self.base.isRelocatable()) if (options.zo.dwarf) |*dwarf| {
3473	self.debug_str_sect_index = try self.addSection("__DWARF", "__debug_str", .{
3474	.flags = macho.S_ATTR_DEBUG,
3475	});
3476	self.debug_info_sect_index = try self.addSection("__DWARF", "__debug_info", .{
3477	.flags = macho.S_ATTR_DEBUG,
3478	});
3479	self.debug_abbrev_sect_index = try self.addSection("__DWARF", "__debug_abbrev", .{
3480	.flags = macho.S_ATTR_DEBUG,
3481	});
3482	self.debug_aranges_sect_index = try self.addSection("__DWARF", "__debug_aranges", .{
3483	.alignment = 4,
3484	.flags = macho.S_ATTR_DEBUG,
3485	});
3486	self.debug_line_sect_index = try self.addSection("__DWARF", "__debug_line", .{
3487	.flags = macho.S_ATTR_DEBUG,
3488	});
3489	self.debug_line_str_sect_index = try self.addSection("__DWARF", "__debug_line_str", .{
3490	.flags = macho.S_ATTR_DEBUG,
3491	});
3492	self.debug_loclists_sect_index = try self.addSection("__DWARF", "__debug_loclists", .{
3493	.flags = macho.S_ATTR_DEBUG,
3494	});
3495	self.debug_rnglists_sect_index = try self.addSection("__DWARF", "__debug_rnglists", .{
3496	.flags = macho.S_ATTR_DEBUG,
3497	});
3498	try dwarf.initMetadata();
3499	};
3500	}
3501
3502	pub fn growSection(self: *MachO, sect_index: u8, needed_size: u64) !void {
3503	if (self.base.isRelocatable()) {
3504	try self.growSectionRelocatable(sect_index, needed_size);
3505	} else {
3506	try self.growSectionNonRelocatable(sect_index, needed_size);
3507	}
3508	}
3509
3510	fn growSectionNonRelocatable(self: *MachO, sect_index: u8, needed_size: u64) !void {
3511	const diags = &self.base.comp.link_diags;
3512	const sect = &self.sections.items(.header)[sect_index];
3513
3514	const seg_id = self.sections.items(.segment_id)[sect_index];
3515	const seg = &self.segments.items[seg_id];
3516
3517	const comp = self.base.comp;
3518	const io = comp.io;
3519
3520	if (!sect.isZerofill()) {
3521	const allocated_size = self.allocatedSize(sect.offset);
3522	if (needed_size > allocated_size) {
3523	const existing_size = sect.size;
3524	sect.size = 0;
3525
3526	// Must move the entire section.
3527	const alignment = self.getPageSize();
3528	const new_offset = try self.findFreeSpace(needed_size, alignment);
3529
3530	log.debug("moving '{s},{s}' from 0x{x} to 0x{x}", .{
3531	sect.segName(),
3532	sect.sectName(),
3533	sect.offset,
3534	new_offset,
3535	});
3536
3537	try self.copyRangeAllZeroOut(sect.offset, new_offset, existing_size);
3538
3539	sect.offset = @intCast(new_offset);
3540	} else if (sect.offset + allocated_size == std.math.maxInt(u64)) {
3541	try self.base.file.?.setLength(io, sect.offset + needed_size);
3542	}
3543	seg.filesize = needed_size;
3544	}
3545	sect.size = needed_size;
3546	seg.fileoff = sect.offset;
3547
3548	const mem_capacity = self.allocatedSizeVirtual(seg.vmaddr);
3549	if (needed_size > mem_capacity) {
3550	var err = try diags.addErrorWithNotes(2);
3551	try err.addMsg("fatal linker error: cannot expand segment seg({d})({s}) in virtual memory", .{
3552	seg_id,
3553	seg.segName(),
3554	});
3555	err.addNote("TODO: emit relocations to memory locations in self-hosted backends", .{});
3556	err.addNote("as a workaround, try increasing pre-allocated virtual memory of each segment", .{});
3557	}
3558
3559	seg.vmsize = needed_size;
3560	}
3561
3562	fn growSectionRelocatable(self: *MachO, sect_index: u8, needed_size: u64) !void {
3563	const comp = self.base.comp;
3564	const io = comp.io;
3565	const sect = &self.sections.items(.header)[sect_index];
3566
3567	if (!sect.isZerofill()) {
3568	const allocated_size = self.allocatedSize(sect.offset);
3569	if (needed_size > allocated_size) {
3570	const existing_size = sect.size;
3571	sect.size = 0;
3572
3573	// Must move the entire section.
3574	const alignment = try math.powi(u32, 2, sect.@"align");
3575	const new_offset = try self.findFreeSpace(needed_size, alignment);
3576	const new_addr = self.findFreeSpaceVirtual(needed_size, alignment);
3577
3578	log.debug("new '{s},{s}' file offset 0x{x} to 0x{x} (0x{x} - 0x{x})", .{
3579	sect.segName(),
3580	sect.sectName(),
3581	new_offset,
3582	new_offset + existing_size,
3583	new_addr,
3584	new_addr + existing_size,
3585	});
3586
3587	try self.copyRangeAll(sect.offset, new_offset, existing_size);
3588
3589	sect.offset = @intCast(new_offset);
3590	sect.addr = new_addr;
3591	} else if (sect.offset + allocated_size == std.math.maxInt(u64)) {
3592	try self.base.file.?.setLength(io, sect.offset + needed_size);
3593	}
3594	}
3595	sect.size = needed_size;
3596	}
3597
3598	pub fn markDirty(self: *MachO, sect_index: u8) void {
3599	if (self.getZigObject()) |zo| {
3600	if (self.debug_info_sect_index.? == sect_index) {
3601	zo.debug_info_header_dirty = true;
3602	} else if (self.debug_line_sect_index.? == sect_index) {
3603	zo.debug_line_header_dirty = true;
3604	} else if (self.debug_abbrev_sect_index.? == sect_index) {
3605	zo.debug_abbrev_dirty = true;
3606	} else if (self.debug_str_sect_index.? == sect_index) {
3607	zo.debug_strtab_dirty = true;
3608	} else if (self.debug_aranges_sect_index.? == sect_index) {
3609	zo.debug_aranges_dirty = true;
3610	}
3611	}
3612	}
3613
3614	pub fn getTarget(self: *const MachO) *const std.Target {
3615	return &self.base.comp.root_mod.resolved_target.result;
3616	}
3617
3618	/// XNU starting with Big Sur running on arm64 is caching inodes of running binaries.
3619	/// Any change to the binary will effectively invalidate the kernel's cache
3620	/// resulting in a SIGKILL on each subsequent run. Since when doing incremental
3621	/// linking we're modifying a binary in-place, this will end up with the kernel
3622	/// killing it on every subsequent run. To circumvent it, we will copy the file
3623	/// into a new inode, remove the original file, and rename the copy to match
3624	/// the original file. This is super messy, but there doesn't seem any other
3625	/// way to please the XNU.
3626	pub fn invalidateKernelCache(io: Io, dir: Io.Dir, sub_path: []const u8) !void {
3627	const tracy = trace(@src());
3628	defer tracy.end();
3629	if (builtin.target.os.tag.isDarwin() and builtin.target.cpu.arch == .aarch64) {
3630	try dir.copyFile(sub_path, dir, sub_path, io, .{});
3631	}
3632	}
3633
3634	inline fn conformUuid(out: *[Md5.digest_length]u8) void {
3635	// LC_UUID uuids should conform to RFC 4122 UUID version 4 & UUID version 5 formats
3636	out[6] = (out[6] & 0x0F) | (3 << 4);
3637	out[8] = (out[8] & 0x3F) | 0x80;
3638	}
3639
3640	pub inline fn getPageSize(self: MachO) u16 {
3641	return switch (self.getTarget().cpu.arch) {
3642	.aarch64 => 0x4000,
3643	.x86_64 => 0x1000,
3644	else => unreachable,
3645	};
3646	}
3647
3648	pub fn requiresCodeSig(self: MachO) bool {
3649	if (self.entitlements) |_| return true;
3650	// TODO: enable once we support this linker option
3651	// if (self.options.adhoc_codesign) |cs| return cs;
3652	const target = self.getTarget();
3653	return switch (target.cpu.arch) {
3654	.aarch64 => switch (target.os.tag) {
3655	.driverkit, .maccatalyst, .macos => true,
3656	.ios, .tvos, .visionos, .watchos => target.abi == .simulator,
3657	else => false,
3658	},
3659	.x86_64 => false,
3660	else => unreachable,
3661	};
3662	}
3663
3664	inline fn requiresThunks(self: MachO) bool {
3665	return self.getTarget().cpu.arch == .aarch64;
3666	}
3667
3668	pub fn isZigSegment(self: MachO, seg_id: u8) bool {
3669	inline for (&[_]?u8{
3670	self.zig_text_seg_index,
3671	self.zig_const_seg_index,
3672	self.zig_data_seg_index,
3673	self.zig_bss_seg_index,
3674	}) |maybe_index| {
3675	if (maybe_index) |index| {
3676	if (index == seg_id) return true;
3677	}
3678	}
3679	return false;
3680	}
3681
3682	pub fn isZigSection(self: MachO, sect_id: u8) bool {
3683	inline for (&[_]?u8{
3684	self.zig_text_sect_index,
3685	self.zig_const_sect_index,
3686	self.zig_data_sect_index,
3687	self.zig_bss_sect_index,
3688	}) |maybe_index| {
3689	if (maybe_index) |index| {
3690	if (index == sect_id) return true;
3691	}
3692	}
3693	return false;
3694	}
3695
3696	pub fn isDebugSection(self: MachO, sect_id: u8) bool {
3697	inline for (&[_]?u8{
3698	self.debug_info_sect_index,
3699	self.debug_abbrev_sect_index,
3700	self.debug_str_sect_index,
3701	self.debug_aranges_sect_index,
3702	self.debug_line_sect_index,
3703	}) |maybe_index| {
3704	if (maybe_index) |index| {
3705	if (index == sect_id) return true;
3706	}
3707	}
3708	return false;
3709	}
3710
3711	pub fn addSegment(self: *MachO, name: []const u8, opts: struct {
3712	vmaddr: u64 = 0,
3713	vmsize: u64 = 0,
3714	fileoff: u64 = 0,
3715	filesize: u64 = 0,
3716	prot: macho.vm_prot_t = .{},
3717	}) error{OutOfMemory}!u8 {
3718	const gpa = self.base.comp.gpa;
3719	const index = @as(u8, @intCast(self.segments.items.len));
3720	try self.segments.append(gpa, .{
3721	.segname = makeStaticString(name),
3722	.vmaddr = opts.vmaddr,
3723	.vmsize = opts.vmsize,
3724	.fileoff = opts.fileoff,
3725	.filesize = opts.filesize,
3726	.maxprot = opts.prot,
3727	.initprot = opts.prot,
3728	.nsects = 0,
3729	.cmdsize = @sizeOf(macho.segment_command_64),
3730	});
3731	return index;
3732	}
3733
3734	const AddSectionOpts = struct {
3735	alignment: u32 = 0,
3736	flags: u32 = macho.S_REGULAR,
3737	reserved1: u32 = 0,
3738	reserved2: u32 = 0,
3739	};
3740
3741	pub fn addSection(
3742	self: *MachO,
3743	segname: []const u8,
3744	sectname: []const u8,
3745	opts: AddSectionOpts,
3746	) !u8 {
3747	const gpa = self.base.comp.gpa;
3748	const index = @as(u8, @intCast(try self.sections.addOne(gpa)));
3749	self.sections.set(index, .{
3750	.segment_id = 0, // Segments will be created automatically later down the pipeline.
3751	.header = .{
3752	.sectname = makeStaticString(sectname),
3753	.segname = makeStaticString(segname),
3754	.@"align" = opts.alignment,
3755	.flags = opts.flags,
3756	.reserved1 = opts.reserved1,
3757	.reserved2 = opts.reserved2,
3758	},
3759	});
3760	return index;
3761	}
3762
3763	pub fn makeStaticString(bytes: []const u8) [16]u8 {
3764	var buf: [16]u8 = @splat(0);
3765	@memcpy(buf[0..bytes.len], bytes);
3766	return buf;
3767	}
3768
3769	pub fn getSegmentByName(self: MachO, segname: []const u8) ?u8 {
3770	for (self.segments.items, 0..) |seg, i| {
3771	if (mem.eql(u8, segname, seg.segName())) return @as(u8, @intCast(i));
3772	} else return null;
3773	}
3774
3775	pub fn getSectionByName(self: MachO, segname: []const u8, sectname: []const u8) ?u8 {
3776	for (self.sections.items(.header), 0..) |header, i| {
3777	if (mem.eql(u8, header.segName(), segname) and mem.eql(u8, header.sectName(), sectname))
3778	return @as(u8, @intCast(i));
3779	} else return null;
3780	}
3781
3782	pub fn getTlsAddress(self: MachO) u64 {
3783	for (self.sections.items(.header)) |header| switch (header.type()) {
3784	macho.S_THREAD_LOCAL_REGULAR,
3785	macho.S_THREAD_LOCAL_ZEROFILL,
3786	=> return header.addr,
3787	else => {},
3788	};
3789	return 0;
3790	}
3791
3792	pub inline fn getTextSegment(self: *MachO) *macho.segment_command_64 {
3793	return &self.segments.items[self.text_seg_index.?];
3794	}
3795
3796	pub inline fn getLinkeditSegment(self: *MachO) *macho.segment_command_64 {
3797	return &self.segments.items[self.linkedit_seg_index.?];
3798	}
3799
3800	pub fn getFile(self: *MachO, index: File.Index) ?File {
3801	const tag = self.files.items(.tags)[index];
3802	return switch (tag) {
3803	.null => null,
3804	.zig_object => .{ .zig_object = &self.files.items(.data)[index].zig_object },
3805	.internal => .{ .internal = &self.files.items(.data)[index].internal },
3806	.object => .{ .object = &self.files.items(.data)[index].object },
3807	.dylib => .{ .dylib = &self.files.items(.data)[index].dylib },
3808	};
3809	}
3810
3811	pub fn getZigObject(self: *MachO) ?*ZigObject {
3812	const index = self.zig_object orelse return null;
3813	return self.getFile(index).?.zig_object;
3814	}
3815
3816	pub fn getInternalObject(self: *MachO) ?*InternalObject {
3817	const index = self.internal_object orelse return null;
3818	return self.getFile(index).?.internal;
3819	}
3820
3821	pub fn addFileHandle(self: *MachO, file: Io.File) !File.HandleIndex {
3822	const gpa = self.base.comp.gpa;
3823	const index: File.HandleIndex = @intCast(self.file_handles.items.len);
3824	const fh = try self.file_handles.addOne(gpa);
3825	fh.* = file;
3826	return index;
3827	}
3828
3829	pub fn getFileHandle(self: MachO, index: File.HandleIndex) File.Handle {
3830	assert(index < self.file_handles.items.len);
3831	return self.file_handles.items[index];
3832	}
3833
3834	pub fn addThunk(self: *MachO) !Thunk.Index {
3835	const index = @as(Thunk.Index, @intCast(self.thunks.items.len));
3836	const thunk = try self.thunks.addOne(self.base.comp.gpa);
3837	thunk.* = .{};
3838	return index;
3839	}
3840
3841	pub fn getThunk(self: *MachO, index: Thunk.Index) *Thunk {
3842	assert(index < self.thunks.items.len);
3843	return &self.thunks.items[index];
3844	}
3845
3846	pub fn eatPrefix(path: []const u8, prefix: []const u8) ?[]const u8 {
3847	if (mem.startsWith(u8, path, prefix)) return path[prefix.len..];
3848	return null;
3849	}
3850
3851	pub fn reportParseError2(
3852	self: *MachO,
3853	file_index: File.Index,
3854	comptime format: []const u8,
3855	args: anytype,
3856	) error{OutOfMemory}!void {
3857	const diags = &self.base.comp.link_diags;
3858	var err = try diags.addErrorWithNotes(1);
3859	try err.addMsg(format, args);
3860	err.addNote("while parsing {f}", .{self.getFile(file_index).?.fmtPath()});
3861	}
3862
3863	fn reportMissingDependencyError(
3864	self: *MachO,
3865	parent: File.Index,
3866	path: []const u8,
3867	checked_paths: []const []const u8,
3868	comptime format: []const u8,
3869	args: anytype,
3870	) error{OutOfMemory}!void {
3871	const diags = &self.base.comp.link_diags;
3872	var err = try diags.addErrorWithNotes(2 + checked_paths.len);
3873	try err.addMsg(format, args);
3874	err.addNote("while resolving {s}", .{path});
3875	err.addNote("a dependency of {f}", .{self.getFile(parent).?.fmtPath()});
3876	for (checked_paths) |p| {
3877	err.addNote("tried {s}", .{p});
3878	}
3879	}
3880
3881	fn reportDependencyError(
3882	self: *MachO,
3883	parent: File.Index,
3884	path: []const u8,
3885	comptime format: []const u8,
3886	args: anytype,
3887	) error{OutOfMemory}!void {
3888	const diags = &self.base.comp.link_diags;
3889	var err = try diags.addErrorWithNotes(2);
3890	try err.addMsg(format, args);
3891	err.addNote("while parsing {s}", .{path});
3892	err.addNote("a dependency of {f}", .{self.getFile(parent).?.fmtPath()});
3893	}
3894
3895	fn reportDuplicates(self: *MachO) error{ HasDuplicates, OutOfMemory }!void {
3896	const tracy = trace(@src());
3897	defer tracy.end();
3898
3899	if (self.dupes.keys().len == 0) return; // Nothing to do
3900
3901	const gpa = self.base.comp.gpa;
3902	const diags = &self.base.comp.link_diags;
3903	const max_notes = 3;
3904
3905	// We will sort by name, and then by file to ensure deterministic output.
3906	var keys = try std.array_list.Managed(SymbolResolver.Index).initCapacity(gpa, self.dupes.keys().len);
3907	defer keys.deinit();
3908	keys.appendSliceAssumeCapacity(self.dupes.keys());
3909	self.sortGlobalSymbolsByName(keys.items);
3910
3911	for (self.dupes.values()) |*refs| {
3912	mem.sort(File.Index, refs.items, {}, std.sort.asc(File.Index));
3913	}
3914
3915	for (keys.items) |key| {
3916	const sym = self.resolver.keys.items[key - 1];
3917	const notes = self.dupes.get(key).?;
3918	const nnotes = @min(notes.items.len, max_notes) + @intFromBool(notes.items.len > max_notes);
3919
3920	var err = try diags.addErrorWithNotes(nnotes + 1);
3921	try err.addMsg("duplicate symbol definition: {s}", .{sym.getName(self)});
3922	err.addNote("defined by {f}", .{sym.getFile(self).?.fmtPath()});
3923
3924	var inote: usize = 0;
3925	while (inote < @min(notes.items.len, max_notes)) : (inote += 1) {
3926	const file = self.getFile(notes.items[inote]).?;
3927	err.addNote("defined by {f}", .{file.fmtPath()});
3928	}
3929
3930	if (notes.items.len > max_notes) {
3931	const remaining = notes.items.len - max_notes;
3932	err.addNote("defined {d} more times", .{remaining});
3933	}
3934	}
3935	return error.HasDuplicates;
3936	}
3937
3938	pub fn getDebugSymbols(self: *MachO) ?*DebugSymbols {
3939	if (self.d_sym) |*ds| return ds;
3940	return null;
3941	}
3942
3943	pub fn ptraceAttach(self: *MachO, pid: std.posix.pid_t) !void {
3944	if (!is_hot_update_compatible) return;
3945
3946	const mach_task = try machTaskForPid(pid);
3947	log.debug("Mach task for pid {d}: {any}", .{ pid, mach_task });
3948	self.hot_state.mach_task = mach_task;
3949
3950	// TODO start exception handler in another thread
3951
3952	// TODO enable ones we register for exceptions
3953	// try std.os.ptrace(std.os.darwin.PT.ATTACHEXC, pid, 0, 0);
3954	}
3955
3956	pub fn ptraceDetach(self: *MachO, pid: std.posix.pid_t) !void {
3957	if (!is_hot_update_compatible) return;
3958
3959	_ = pid;
3960
3961	// TODO stop exception handler
3962
3963	// TODO see comment in ptraceAttach
3964	// try std.os.ptrace(std.os.darwin.PT.DETACH, pid, 0, 0);
3965
3966	self.hot_state.mach_task = null;
3967	}
3968
3969	pub fn dumpState(self: *MachO) std.fmt.Alt(*MachO, fmtDumpState) {
3970	return .{ .data = self };
3971	}
3972
3973	fn fmtDumpState(self: *MachO, w: *Writer) Writer.Error!void {
3974	if (self.getZigObject()) |zo| {
3975	try w.print("zig_object({d}) : {s}\n", .{ zo.index, zo.basename });
3976	try w.print("{f}{f}\n", .{
3977	zo.fmtAtoms(self),
3978	zo.fmtSymtab(self),
3979	});
3980	}
3981	for (self.objects.items) |index| {
3982	const object = self.getFile(index).?.object;
3983	try w.print("object({d}) : {f} : has_debug({})", .{
3984	index,
3985	object.fmtPath(),
3986	object.hasDebugInfo(),
3987	});
3988	if (!object.alive) try w.writeAll(" : ([*])");
3989	try w.writeByte('\n');
3990	try w.print("{f}{f}{f}{f}{f}\n", .{
3991	object.fmtAtoms(self),
3992	object.fmtCies(self),
3993	object.fmtFdes(self),
3994	object.fmtUnwindRecords(self),
3995	object.fmtSymtab(self),
3996	});
3997	}
3998	for (self.dylibs.items) |index| {
3999	const dylib = self.getFile(index).?.dylib;
4000	try w.print("dylib({d}) : {f} : needed({}) : weak({})", .{
4001	index,
4002	@as(Path, dylib.path),
4003	dylib.needed,
4004	dylib.weak,
4005	});
4006	if (!dylib.isAlive(self)) try w.writeAll(" : ([*])");
4007	try w.writeByte('\n');
4008	try w.print("{f}\n", .{dylib.fmtSymtab(self)});
4009	}
4010	if (self.getInternalObject()) |internal| {
4011	try w.print("internal({d}) : internal\n", .{internal.index});
4012	try w.print("{f}{f}\n", .{ internal.fmtAtoms(self), internal.fmtSymtab(self) });
4013	}
4014	try w.writeAll("thunks\n");
4015	for (self.thunks.items, 0..) |thunk, index| {
4016	try w.print("thunk({d}) : {f}\n", .{ index, thunk.fmt(self) });
4017	}
4018	try w.print("stubs\n{f}\n", .{self.stubs.fmt(self)});
4019	try w.print("objc_stubs\n{f}\n", .{self.objc_stubs.fmt(self)});
4020	try w.print("got\n{f}\n", .{self.got.fmt(self)});
4021	try w.print("tlv_ptr\n{f}\n", .{self.tlv_ptr.fmt(self)});
4022	try w.writeByte('\n');
4023	try w.print("sections\n{f}\n", .{self.fmtSections()});
4024	try w.print("segments\n{f}\n", .{self.fmtSegments()});
4025	}
4026
4027	fn fmtSections(self: *MachO) std.fmt.Alt(*MachO, formatSections) {
4028	return .{ .data = self };
4029	}
4030
4031	fn formatSections(self: *MachO, w: *Writer) Writer.Error!void {
4032	const slice = self.sections.slice();
4033	for (slice.items(.header), slice.items(.segment_id), 0..) |header, seg_id, i| {
4034	try w.print(
4035	"sect({d}) : seg({d}) : {s},{s} : @{x} ({x}) : align({x}) : size({x}) : relocs({x};{d})\n",
4036	.{
4037	i, seg_id, header.segName(), header.sectName(), header.addr, header.offset,
4038	header.@"align", header.size, header.reloff, header.nreloc,
4039	},
4040	);
4041	}
4042	}
4043
4044	fn fmtSegments(self: *MachO) std.fmt.Alt(*MachO, formatSegments) {
4045	return .{ .data = self };
4046	}
4047
4048	fn formatSegments(self: *MachO, w: *Writer) Writer.Error!void {
4049	for (self.segments.items, 0..) |seg, i| {
4050	try w.print("seg({d}) : {s} : @{x}-{x} ({x}-{x})\n", .{
4051	i, seg.segName(), seg.vmaddr, seg.vmaddr + seg.vmsize,
4052	seg.fileoff, seg.fileoff + seg.filesize,
4053	});
4054	}
4055	}
4056
4057	pub fn fmtSectType(tt: u8) std.fmt.Alt(u8, formatSectType) {
4058	return .{ .data = tt };
4059	}
4060
4061	fn formatSectType(tt: u8, w: *Writer) Writer.Error!void {
4062	const name = switch (tt) {
4063	macho.S_REGULAR => "REGULAR",
4064	macho.S_ZEROFILL => "ZEROFILL",
4065	macho.S_CSTRING_LITERALS => "CSTRING_LITERALS",
4066	macho.S_4BYTE_LITERALS => "4BYTE_LITERALS",
4067	macho.S_8BYTE_LITERALS => "8BYTE_LITERALS",
4068	macho.S_16BYTE_LITERALS => "16BYTE_LITERALS",
4069	macho.S_LITERAL_POINTERS => "LITERAL_POINTERS",
4070	macho.S_NON_LAZY_SYMBOL_POINTERS => "NON_LAZY_SYMBOL_POINTERS",
4071	macho.S_LAZY_SYMBOL_POINTERS => "LAZY_SYMBOL_POINTERS",
4072	macho.S_SYMBOL_STUBS => "SYMBOL_STUBS",
4073	macho.S_MOD_INIT_FUNC_POINTERS => "MOD_INIT_FUNC_POINTERS",
4074	macho.S_MOD_TERM_FUNC_POINTERS => "MOD_TERM_FUNC_POINTERS",
4075	macho.S_COALESCED => "COALESCED",
4076	macho.S_GB_ZEROFILL => "GB_ZEROFILL",
4077	macho.S_INTERPOSING => "INTERPOSING",
4078	macho.S_DTRACE_DOF => "DTRACE_DOF",
4079	macho.S_THREAD_LOCAL_REGULAR => "THREAD_LOCAL_REGULAR",
4080	macho.S_THREAD_LOCAL_ZEROFILL => "THREAD_LOCAL_ZEROFILL",
4081	macho.S_THREAD_LOCAL_VARIABLES => "THREAD_LOCAL_VARIABLES",
4082	macho.S_THREAD_LOCAL_VARIABLE_POINTERS => "THREAD_LOCAL_VARIABLE_POINTERS",
4083	macho.S_THREAD_LOCAL_INIT_FUNCTION_POINTERS => "THREAD_LOCAL_INIT_FUNCTION_POINTERS",
4084	macho.S_INIT_FUNC_OFFSETS => "INIT_FUNC_OFFSETS",
4085	else => |x| return w.print("UNKNOWN({x})", .{x}),
4086	};
4087	try w.print("{s}", .{name});
4088	}
4089
4090	const is_hot_update_compatible = switch (builtin.target.os.tag) {
4091	.maccatalyst, .macos => true,
4092	else => false,
4093	};
4094
4095	const default_entry_symbol_name = "_main";
4096
4097	const Section = struct {
4098	header: macho.section_64,
4099	segment_id: u8,
4100	atoms: std.ArrayList(Ref) = .empty,
4101	free_list: std.ArrayList(Atom.Index) = .empty,
4102	last_atom_index: Atom.Index = 0,
4103	thunks: std.ArrayList(Thunk.Index) = .empty,
4104	out: std.ArrayList(u8) = .empty,
4105	relocs: std.ArrayList(macho.relocation_info) = .empty,
4106	};
4107
4108	pub const LiteralPool = struct {
4109	table: std.array_hash_map.Auto(void, void) = .empty,
4110	keys: std.ArrayList(Key) = .empty,
4111	values: std.ArrayList(MachO.Ref) = .empty,
4112	data: std.ArrayList(u8) = .empty,
4113
4114	pub fn deinit(lp: *LiteralPool, allocator: Allocator) void {
4115	lp.table.deinit(allocator);
4116	lp.keys.deinit(allocator);
4117	lp.values.deinit(allocator);
4118	lp.data.deinit(allocator);
4119	}
4120
4121	const InsertResult = struct {
4122	found_existing: bool,
4123	index: Index,
4124	ref: *MachO.Ref,
4125	};
4126
4127	pub fn getSymbolRef(lp: LiteralPool, index: Index) MachO.Ref {
4128	assert(index < lp.values.items.len);
4129	return lp.values.items[index];
4130	}
4131
4132	pub fn getSymbol(lp: LiteralPool, index: Index, macho_file: *MachO) *Symbol {
4133	return lp.getSymbolRef(index).getSymbol(macho_file).?;
4134	}
4135
4136	pub fn insert(lp: *LiteralPool, allocator: Allocator, @"type": u8, string: []const u8) !InsertResult {
4137	const size: u32 = @intCast(string.len);
4138	try lp.data.ensureUnusedCapacity(allocator, size);
4139	const off: u32 = @intCast(lp.data.items.len);
4140	lp.data.appendSliceAssumeCapacity(string);
4141	const adapter = Adapter{ .lp = lp };
4142	const key = Key{ .off = off, .size = size, .seed = @"type" };
4143	const gop = try lp.table.getOrPutAdapted(allocator, key, adapter);
4144	if (!gop.found_existing) {
4145	try lp.keys.append(allocator, key);
4146	_ = try lp.values.addOne(allocator);
4147	}
4148	return .{
4149	.found_existing = gop.found_existing,
4150	.index = @intCast(gop.index),
4151	.ref = &lp.values.items[gop.index],
4152	};
4153	}
4154
4155	const Key = struct {
4156	off: u32,
4157	size: u32,
4158	seed: u8,
4159
4160	fn getData(key: Key, lp: *const LiteralPool) []const u8 {
4161	return lp.data.items[key.off..][0..key.size];
4162	}
4163
4164	fn eql(key: Key, other: Key, lp: *const LiteralPool) bool {
4165	const key_data = key.getData(lp);
4166	const other_data = other.getData(lp);
4167	return mem.eql(u8, key_data, other_data);
4168	}
4169
4170	fn hash(key: Key, lp: *const LiteralPool) u32 {
4171	const data = key.getData(lp);
4172	return @truncate(Hash.hash(key.seed, data));
4173	}
4174	};
4175
4176	const Adapter = struct {
4177	lp: *const LiteralPool,
4178
4179	pub fn eql(ctx: @This(), key: Key, b_void: void, b_map_index: usize) bool {
4180	_ = b_void;
4181	const other = ctx.lp.keys.items[b_map_index];
4182	return key.eql(other, ctx.lp);
4183	}
4184
4185	pub fn hash(ctx: @This(), key: Key) u32 {
4186	return key.hash(ctx.lp);
4187	}
4188	};
4189
4190	pub const Index = u32;
4191	};
4192
4193	const HotUpdateState = struct {
4194	mach_task: ?MachTask = null,
4195	};
4196
4197	pub const SymtabCtx = struct {
4198	ilocal: u32 = 0,
4199	istab: u32 = 0,
4200	iexport: u32 = 0,
4201	iimport: u32 = 0,
4202	nlocals: u32 = 0,
4203	nstabs: u32 = 0,
4204	nexports: u32 = 0,
4205	nimports: u32 = 0,
4206	stroff: u32 = 0,
4207	strsize: u32 = 0,
4208	};
4209
4210	pub const null_sym = macho.nlist_64{
4211	.n_strx = 0,
4212	.n_type = @bitCast(@as(u8, 0)),
4213	.n_sect = 0,
4214	.n_desc = @bitCast(@as(u16, 0)),
4215	.n_value = 0,
4216	};
4217
4218	pub const Platform = struct {
4219	os_tag: std.Target.Os.Tag,
4220	abi: std.Target.Abi,
4221	version: std.SemanticVersion,
4222
4223	/// Using Apple's ld64 as our blueprint, `min_version` as well as `sdk_version` are set to
4224	/// the extracted minimum platform version.
4225	pub fn fromLoadCommand(lc: macho.LoadCommandIterator.LoadCommand) Platform {
4226	switch (lc.hdr.cmd) {
4227	.BUILD_VERSION => {
4228	const cmd = lc.cast(macho.build_version_command).?;
4229	return .{
4230	.os_tag = switch (cmd.platform) {
4231	.DRIVERKIT => .driverkit,
4232	.IOS, .IOSSIMULATOR => .ios,
4233	.MACCATALYST => .maccatalyst,
4234	.MACOS => .macos,
4235	.TVOS, .TVOSSIMULATOR => .tvos,
4236	.VISIONOS, .VISIONOSSIMULATOR => .visionos,
4237	.WATCHOS, .WATCHOSSIMULATOR => .watchos,
4238	else => @panic("TODO"),
4239	},
4240	.abi = switch (cmd.platform) {
4241	.IOSSIMULATOR,
4242	.TVOSSIMULATOR,
4243	.VISIONOSSIMULATOR,
4244	.WATCHOSSIMULATOR,
4245	=> .simulator,
4246	else => .none,
4247	},
4248	.version = appleVersionToSemanticVersion(cmd.minos),
4249	};
4250	},
4251	.VERSION_MIN_IPHONEOS,
4252	.VERSION_MIN_MACOSX,
4253	.VERSION_MIN_TVOS,
4254	.VERSION_MIN_WATCHOS,
4255	=> {
4256	// We can't distinguish Mac Catalyst here, but this is legacy stuff anyway.
4257	const cmd = lc.cast(macho.version_min_command).?;
4258	return .{
4259	.os_tag = switch (lc.hdr.cmd) {
4260	.VERSION_MIN_IPHONEOS => .ios,
4261	.VERSION_MIN_MACOSX => .macos,
4262	.VERSION_MIN_TVOS => .tvos,
4263	.VERSION_MIN_WATCHOS => .watchos,
4264	else => unreachable,
4265	},
4266	.abi = .none,
4267	.version = appleVersionToSemanticVersion(cmd.version),
4268	};
4269	},
4270	else => unreachable,
4271	}
4272	}
4273
4274	pub fn fromTarget(target: *const std.Target) Platform {
4275	return .{
4276	.os_tag = target.os.tag,
4277	.abi = target.abi,
4278	.version = target.os.version_range.semver.min,
4279	};
4280	}
4281
4282	pub fn toAppleVersion(plat: Platform) u32 {
4283	return semanticVersionToAppleVersion(plat.version);
4284	}
4285
4286	pub fn toApplePlatform(plat: Platform) macho.PLATFORM {
4287	return switch (plat.os_tag) {
4288	.driverkit => .DRIVERKIT,
4289	.ios => if (plat.abi == .simulator) .IOSSIMULATOR else .IOS,
4290	.maccatalyst => .MACCATALYST,
4291	.macos => .MACOS,
4292	.tvos => if (plat.abi == .simulator) .TVOSSIMULATOR else .TVOS,
4293	.visionos => if (plat.abi == .simulator) .VISIONOSSIMULATOR else .VISIONOS,
4294	.watchos => if (plat.abi == .simulator) .WATCHOSSIMULATOR else .WATCHOS,
4295	else => unreachable,
4296	};
4297	}
4298
4299	pub fn isBuildVersionCompatible(plat: Platform) bool {
4300	inline for (supported_platforms) |sup_plat| {
4301	if (sup_plat[0] == plat.os_tag and sup_plat[1] == plat.abi) {
4302	return sup_plat[2] <= plat.toAppleVersion();
4303	}
4304	}
4305	return false;
4306	}
4307
4308	pub fn isVersionMinCompatible(plat: Platform) bool {
4309	inline for (supported_platforms) |sup_plat| {
4310	if (sup_plat[0] == plat.os_tag and sup_plat[1] == plat.abi) {
4311	return sup_plat[3] <= plat.toAppleVersion();
4312	}
4313	}
4314	return false;
4315	}
4316
4317	pub fn fmtTarget(plat: Platform, cpu_arch: std.Target.Cpu.Arch) std.fmt.Alt(Format, Format.target) {
4318	return .{ .data = .{ .platform = plat, .cpu_arch = cpu_arch } };
4319	}
4320
4321	const Format = struct {
4322	platform: Platform,
4323	cpu_arch: std.Target.Cpu.Arch,
4324
4325	pub fn target(f: Format, w: *Writer) Writer.Error!void {
4326	try w.print("{s}-{s}", .{ @tagName(f.cpu_arch), @tagName(f.platform.os_tag) });
4327	if (f.platform.abi != .none) {
4328	try w.print("-{s}", .{@tagName(f.platform.abi)});
4329	}
4330	}
4331	};
4332
4333	/// Caller owns the memory.
4334	pub fn allocPrintTarget(plat: Platform, gpa: Allocator, cpu_arch: std.Target.Cpu.Arch) error{OutOfMemory}![]u8 {
4335	var buffer = std.array_list.Managed(u8).init(gpa);
4336	defer buffer.deinit();
4337	try buffer.writer().print("{f}", .{plat.fmtTarget(cpu_arch)});
4338	return buffer.toOwnedSlice();
4339	}
4340
4341	pub fn eqlTarget(plat: Platform, other: Platform) bool {
4342	return plat.os_tag == other.os_tag and plat.abi == other.abi;
4343	}
4344	};
4345
4346	const SupportedPlatforms = struct {
4347	std.Target.Os.Tag,
4348	std.Target.Abi,
4349	u32, // Min platform version for which to emit LC_BUILD_VERSION
4350	u32, // Min supported platform version
4351	};
4352
4353	// Source: https://github.com/apple-oss-distributions/ld64/blob/59a99ab60399c5e6c49e6945a9e1049c42b71135/src/ld/PlatformSupport.cpp#L52
4354	// zig fmt: off
4355	const supported_platforms = [_]SupportedPlatforms{
4356	.{ .driverkit, .none, 0x130000, 0x130000 },
4357	.{ .ios, .none, 0x0C0000, 0x070000 },
4358	.{ .ios, .simulator, 0x0D0000, 0x080000 },
4359	.{ .maccatalyst, .none, 0x0D0000, 0x0D0000 },
4360	.{ .macos, .none, 0x0A0E00, 0x0A0800 },
4361	.{ .tvos, .none, 0x0C0000, 0x070000 },
4362	.{ .tvos, .simulator, 0x0D0000, 0x080000 },
4363	.{ .visionos, .none, 0x010000, 0x010000 },
4364	.{ .visionos, .simulator, 0x010000, 0x010000 },
4365	.{ .watchos, .none, 0x050000, 0x020000 },
4366	.{ .watchos, .simulator, 0x060000, 0x020000 },
4367	};
4368	// zig fmt: on
4369
4370	pub inline fn semanticVersionToAppleVersion(version: std.SemanticVersion) u32 {
4371	const major = version.major;
4372	const minor = version.minor;
4373	const patch = version.patch;
4374	return (@as(u32, @intCast(major)) << 16) | (@as(u32, @intCast(minor)) << 8) | @as(u32, @intCast(patch));
4375	}
4376
4377	pub inline fn appleVersionToSemanticVersion(version: u32) std.SemanticVersion {
4378	return .{
4379	.major = @as(u16, @truncate(version >> 16)),
4380	.minor = @as(u8, @truncate(version >> 8)),
4381	.patch = @as(u8, @truncate(version)),
4382	};
4383	}
4384
4385	fn inferSdkVersion(comp: *Compilation, sdk_layout: SdkLayout) ?std.SemanticVersion {
4386	const gpa = comp.gpa;
4387
4388	var arena_allocator = std.heap.ArenaAllocator.init(gpa);
4389	defer arena_allocator.deinit();
4390	const arena = arena_allocator.allocator();
4391
4392	const io = comp.io;
4393
4394	const sdk_dir = switch (sdk_layout) {
4395	.sdk => comp.sysroot.?,
4396	.vendored => fs.path.join(arena, &.{ comp.dirs.zig_lib.path.?, "libc", "darwin" }) catch return null,
4397	};
4398	if (readSdkVersionFromSettings(arena, io, sdk_dir)) |ver| {
4399	return parseSdkVersion(ver);
4400	} else |_| {
4401	// Read from settings should always succeed when vendored.
4402	// TODO: convert to fatal linker error
4403	if (sdk_layout == .vendored) @panic("zig installation bug: unable to parse SDK version");
4404	}
4405
4406	// infer from pathname
4407	const stem = fs.path.stem(sdk_dir);
4408	const start = for (stem, 0..) |c, i| {
4409	if (std.ascii.isDigit(c)) break i;
4410	} else stem.len;
4411	const end = for (stem[start..], start..) |c, i| {
4412	if (std.ascii.isDigit(c) or c == '.') continue;
4413	break i;
4414	} else stem.len;
4415	return parseSdkVersion(stem[start..end]);
4416	}
4417
4418	// Official Apple SDKs ship with a `SDKSettings.json` located at the top of SDK fs layout.
4419	// Use property `MinimalDisplayName` to determine version.
4420	// The file/property is also available with vendored libc.
4421	fn readSdkVersionFromSettings(arena: Allocator, io: Io, dir: []const u8) ![]const u8 {
4422	const sdk_path = try fs.path.join(arena, &.{ dir, "SDKSettings.json" });
4423	const contents = try Io.Dir.cwd().readFileAlloc(io, sdk_path, arena, .limited(std.math.maxInt(u16)));
4424	const parsed = try std.json.parseFromSlice(std.json.Value, arena, contents, .{});
4425	if (parsed.value.object.get("MinimalDisplayName")) |ver| return ver.string;
4426	return error.SdkVersionFailure;
4427	}
4428
4429	// Versions reported by Apple aren't exactly semantically valid as they usually omit
4430	// the patch component, so we parse SDK value by hand.
4431	fn parseSdkVersion(raw: []const u8) ?std.SemanticVersion {
4432	var parsed: std.SemanticVersion = .{
4433	.major = 0,
4434	.minor = 0,
4435	.patch = 0,
4436	};
4437
4438	const parseNext = struct {
4439	fn parseNext(it: anytype) ?u16 {
4440	const nn = it.next() orelse return null;
4441	return std.fmt.parseInt(u16, nn, 10) catch null;
4442	}
4443	}.parseNext;
4444
4445	var it = std.mem.splitAny(u8, raw, ".");
4446	parsed.major = parseNext(&it) orelse return null;
4447	parsed.minor = parseNext(&it) orelse return null;
4448	parsed.patch = parseNext(&it) orelse 0;
4449	return parsed;
4450	}
4451
4452	/// When allocating, the ideal_capacity is calculated by
4453	/// actual_capacity + (actual_capacity / ideal_factor)
4454	const ideal_factor = 3;
4455
4456	/// In order for a slice of bytes to be considered eligible to keep metadata pointing at
4457	/// it as a possible place to put new symbols, it must have enough room for this many bytes
4458	/// (plus extra for reserved capacity).
4459	const minimum_text_block_size = 64;
4460	pub const min_text_capacity = padToIdeal(minimum_text_block_size);
4461
4462	/// Default virtual memory offset corresponds to the size of __PAGEZERO segment and
4463	/// start of __TEXT segment.
4464	pub const default_pagezero_size: u64 = 0x100000000;
4465
4466	/// We commit 0x1000 = 4096 bytes of space to the header and
4467	/// the table of load commands. This should be plenty for any
4468	/// potential future extensions.
4469	pub const default_headerpad_size: u32 = 0x1000;
4470
4471	const SystemLib = struct {
4472	path: Path,
4473	needed: bool = false,
4474	weak: bool = false,
4475	hidden: bool = false,
4476	reexport: bool = false,
4477	must_link: bool = false,
4478
4479	fn fromLinkInput(link_input: link.Input) SystemLib {
4480	return switch (link_input) {
4481	.dso_exact => unreachable,
4482	.res => unreachable,
4483	.object, .archive => |obj| .{
4484	.path = obj.path,
4485	.must_link = obj.must_link,
4486	.hidden = obj.hidden,
4487	},
4488	.dso => |dso| .{
4489	.path = dso.path,
4490	.needed = dso.needed,
4491	.weak = dso.weak,
4492	.reexport = dso.reexport,
4493	},
4494	};
4495	}
4496	};
4497
4498	pub const SdkLayout = std.zig.LibCDirs.DarwinSdkLayout;
4499
4500	const UndefinedTreatment = enum {
4501	@"error",
4502	warn,
4503	suppress,
4504	dynamic_lookup,
4505	};
4506
4507	/// A reference to atom or symbol in an input file.
4508	/// If file == 0, symbol is an undefined global.
4509	pub const Ref = struct {
4510	index: u32,
4511	file: File.Index,
4512
4513	pub fn eql(ref: Ref, other: Ref) bool {
4514	return ref.index == other.index and ref.file == other.file;
4515	}
4516
4517	pub fn lessThan(ref: Ref, other: Ref) bool {
4518	if (ref.file == other.file) {
4519	return ref.index < other.index;
4520	}
4521	return ref.file < other.file;
4522	}
4523
4524	pub fn getFile(ref: Ref, macho_file: *MachO) ?File {
4525	return macho_file.getFile(ref.file);
4526	}
4527
4528	pub fn getAtom(ref: Ref, macho_file: *MachO) ?*Atom {
4529	const file = ref.getFile(macho_file) orelse return null;
4530	return file.getAtom(ref.index);
4531	}
4532
4533	pub fn getSymbol(ref: Ref, macho_file: *MachO) ?*Symbol {
4534	const file = ref.getFile(macho_file) orelse return null;
4535	return switch (file) {
4536	inline else => |x| &x.symbols.items[ref.index],
4537	};
4538	}
4539
4540	pub fn format(ref: Ref, bw: *Writer) Writer.Error!void {
4541	try bw.print("%{d} in file({d})", .{ ref.index, ref.file });
4542	}
4543	};
4544
4545	pub const SymbolResolver = struct {
4546	keys: std.ArrayList(Key) = .empty,
4547	values: std.ArrayList(Ref) = .empty,
4548	table: std.array_hash_map.Auto(void, void) = .empty,
4549
4550	const Result = struct {
4551	found_existing: bool,
4552	index: Index,
4553	ref: *Ref,
4554	};
4555
4556	pub fn deinit(resolver: *SymbolResolver, allocator: Allocator) void {
4557	resolver.keys.deinit(allocator);
4558	resolver.values.deinit(allocator);
4559	resolver.table.deinit(allocator);
4560	}
4561
4562	pub fn getOrPut(
4563	resolver: *SymbolResolver,
4564	allocator: Allocator,
4565	ref: Ref,
4566	macho_file: *MachO,
4567	) !Result {
4568	const adapter = Adapter{ .keys = resolver.keys.items, .macho_file = macho_file };
4569	const key = Key{ .index = ref.index, .file = ref.file };
4570	const gop = try resolver.table.getOrPutAdapted(allocator, key, adapter);
4571	if (!gop.found_existing) {
4572	try resolver.keys.append(allocator, key);
4573	_ = try resolver.values.addOne(allocator);
4574	}
4575	return .{
4576	.found_existing = gop.found_existing,
4577	.index = @intCast(gop.index + 1),
4578	.ref = &resolver.values.items[gop.index],
4579	};
4580	}
4581
4582	pub fn get(resolver: SymbolResolver, index: Index) ?Ref {
4583	if (index == 0) return null;
4584	return resolver.values.items[index - 1];
4585	}
4586
4587	pub fn reset(resolver: *SymbolResolver) void {
4588	resolver.keys.clearRetainingCapacity();
4589	resolver.values.clearRetainingCapacity();
4590	resolver.table.clearRetainingCapacity();
4591	}
4592
4593	const Key = struct {
4594	index: Symbol.Index,
4595	file: File.Index,
4596
4597	fn getName(key: Key, macho_file: *MachO) [:0]const u8 {
4598	const ref = Ref{ .index = key.index, .file = key.file };
4599	return ref.getSymbol(macho_file).?.getName(macho_file);
4600	}
4601
4602	pub fn getFile(key: Key, macho_file: *MachO) ?File {
4603	const ref = Ref{ .index = key.index, .file = key.file };
4604	return ref.getFile(macho_file);
4605	}
4606
4607	fn eql(key: Key, other: Key, macho_file: *MachO) bool {
4608	const key_name = key.getName(macho_file);
4609	const other_name = other.getName(macho_file);
4610	return mem.eql(u8, key_name, other_name);
4611	}
4612
4613	fn hash(key: Key, macho_file: *MachO) u32 {
4614	const name = key.getName(macho_file);
4615	return @truncate(Hash.hash(0, name));
4616	}
4617	};
4618
4619	const Adapter = struct {
4620	keys: []const Key,
4621	macho_file: *MachO,
4622
4623	pub fn eql(ctx: @This(), key: Key, b_void: void, b_map_index: usize) bool {
4624	_ = b_void;
4625	const other = ctx.keys[b_map_index];
4626	return key.eql(other, ctx.macho_file);
4627	}
4628
4629	pub fn hash(ctx: @This(), key: Key) u32 {
4630	return key.hash(ctx.macho_file);
4631	}
4632	};
4633
4634	pub const Index = u32;
4635	};
4636
4637	pub const String = struct {
4638	pos: u32 = 0,
4639	len: u32 = 0,
4640	};
4641
4642	pub const UndefRefs = union(enum) {
4643	force_undefined,
4644	entry,
4645	dyld_stub_binder,
4646	objc_msgsend,
4647	refs: std.ArrayList(Ref),
4648
4649	pub fn deinit(self: *UndefRefs, allocator: Allocator) void {
4650	switch (self.*) {
4651	.refs => |*refs| refs.deinit(allocator),
4652	else => {},
4653	}
4654	}
4655	};
4656
4657	pub const MachError = error{
4658	/// Not enough permissions held to perform the requested kernel
4659	/// call.
4660	PermissionDenied,
4661	} || std.posix.UnexpectedError;
4662
4663	pub const MachTask = extern struct {
4664	port: std.c.mach_port_name_t,
4665
4666	pub fn isValid(self: MachTask) bool {
4667	return self.port != std.c.TASK_NULL;
4668	}
4669
4670	pub fn pidForTask(self: MachTask) MachError!std.c.pid_t {
4671	var pid: std.c.pid_t = undefined;
4672	switch (getKernError(std.c.pid_for_task(self.port, &pid))) {
4673	.SUCCESS => return pid,
4674	.FAILURE => return error.PermissionDenied,
4675	else => |err| return unexpectedKernError(err),
4676	}
4677	}
4678
4679	pub fn allocatePort(self: MachTask, right: std.c.MACH_PORT_RIGHT) MachError!MachTask {
4680	var out_port: std.c.mach_port_name_t = undefined;
4681	switch (getKernError(std.c.mach_port_allocate(
4682	self.port,
4683	@backingInt(right),
4684	&out_port,
4685	))) {
4686	.SUCCESS => return .{ .port = out_port },
4687	.FAILURE => return error.PermissionDenied,
4688	else => |err| return unexpectedKernError(err),
4689	}
4690	}
4691
4692	pub fn deallocatePort(self: MachTask, port: MachTask) void {
4693	_ = getKernError(std.c.mach_port_deallocate(self.port, port.port));
4694	}
4695
4696	pub fn insertRight(self: MachTask, port: MachTask, msg: std.c.MACH_MSG_TYPE) !void {
4697	switch (getKernError(std.c.mach_port_insert_right(
4698	self.port,
4699	port.port,
4700	port.port,
4701	@backingInt(msg),
4702	))) {
4703	.SUCCESS => return,
4704	.FAILURE => return error.PermissionDenied,
4705	else => |err| return unexpectedKernError(err),
4706	}
4707	}
4708
4709	pub const PortInfo = struct {
4710	mask: std.c.exception_mask_t,
4711	masks: [std.c.EXC.TYPES_COUNT]std.c.exception_mask_t,
4712	ports: [std.c.EXC.TYPES_COUNT]std.c.mach_port_t,
4713	behaviors: [std.c.EXC.TYPES_COUNT]std.c.exception_behavior_t,
4714	flavors: [std.c.EXC.TYPES_COUNT]std.c.thread_state_flavor_t,
4715	count: std.c.mach_msg_type_number_t,
4716	};
4717
4718	pub fn getExceptionPorts(self: MachTask, mask: std.c.exception_mask_t) !PortInfo {
4719	var info: PortInfo = .{
4720	.mask = mask,
4721	.masks = undefined,
4722	.ports = undefined,
4723	.behaviors = undefined,
4724	.flavors = undefined,
4725	.count = 0,
4726	};
4727	info.count = info.ports.len / @sizeOf(std.c.mach_port_t);
4728
4729	switch (getKernError(std.c.task_get_exception_ports(
4730	self.port,
4731	info.mask,
4732	&info.masks,
4733	&info.count,
4734	&info.ports,
4735	&info.behaviors,
4736	&info.flavors,
4737	))) {
4738	.SUCCESS => return info,
4739	.FAILURE => return error.PermissionDenied,
4740	else => |err| return unexpectedKernError(err),
4741	}
4742	}
4743
4744	pub fn setExceptionPorts(
4745	self: MachTask,
4746	mask: std.c.exception_mask_t,
4747	new_port: MachTask,
4748	behavior: std.c.exception_behavior_t,
4749	new_flavor: std.c.thread_state_flavor_t,
4750	) !void {
4751	switch (getKernError(std.c.task_set_exception_ports(
4752	self.port,
4753	mask,
4754	new_port.port,
4755	behavior,
4756	new_flavor,
4757	))) {
4758	.SUCCESS => return,
4759	.FAILURE => return error.PermissionDenied,
4760	else => |err| return unexpectedKernError(err),
4761	}
4762	}
4763
4764	pub const RegionInfo = struct {
4765	pub const Tag = enum {
4766	basic,
4767	extended,
4768	top,
4769	};
4770
4771	base_addr: u64,
4772	tag: Tag,
4773	info: union {
4774	basic: std.c.vm_region_basic_info_64,
4775	extended: std.c.vm_region_extended_info,
4776	top: std.c.vm_region_top_info,
4777	},
4778	};
4779
4780	pub fn getRegionInfo(
4781	task: MachTask,
4782	address: u64,
4783	len: usize,
4784	tag: RegionInfo.Tag,
4785	) MachError!RegionInfo {
4786	var info: RegionInfo = .{
4787	.base_addr = address,
4788	.tag = tag,
4789	.info = undefined,
4790	};
4791	switch (tag) {
4792	.basic => info.info = .{ .basic = undefined },
4793	.extended => info.info = .{ .extended = undefined },
4794	.top => info.info = .{ .top = undefined },
4795	}
4796	var base_len: std.c.mach_vm_size_t = if (len == 1) 2 else len;
4797	var objname: std.c.mach_port_t = undefined;
4798	var count: std.c.mach_msg_type_number_t = switch (tag) {
4799	.basic => std.c.VM.REGION.BASIC_INFO_COUNT,
4800	.extended => std.c.VM.REGION.EXTENDED_INFO_COUNT,
4801	.top => std.c.VM.REGION.TOP_INFO_COUNT,
4802	};
4803	switch (getKernError(std.c.mach_vm_region(
4804	task.port,
4805	&info.base_addr,
4806	&base_len,
4807	switch (tag) {
4808	.basic => std.c.VM.REGION.BASIC_INFO_64,
4809	.extended => std.c.VM.REGION.EXTENDED_INFO,
4810	.top => std.c.VM.REGION.TOP_INFO,
4811	},
4812	switch (tag) {
4813	.basic => @as(std.c.vm_region_info_t, @ptrCast(&info.info.basic)),
4814	.extended => @as(std.c.vm_region_info_t, @ptrCast(&info.info.extended)),
4815	.top => @as(std.c.vm_region_info_t, @ptrCast(&info.info.top)),
4816	},
4817	&count,
4818	&objname,
4819	))) {
4820	.SUCCESS => return info,
4821	.FAILURE => return error.PermissionDenied,
4822	else => |err| return unexpectedKernError(err),
4823	}
4824	}
4825
4826	pub const RegionSubmapInfo = struct {
4827	pub const Tag = enum {
4828	short,
4829	full,
4830	};
4831
4832	tag: Tag,
4833	base_addr: u64,
4834	info: union {
4835	short: std.c.vm_region_submap_short_info_64,
4836	full: std.c.vm_region_submap_info_64,
4837	},
4838	};
4839
4840	pub fn getRegionSubmapInfo(
4841	task: MachTask,
4842	address: u64,
4843	len: usize,
4844	nesting_depth: u32,
4845	tag: RegionSubmapInfo.Tag,
4846	) MachError!RegionSubmapInfo {
4847	var info: RegionSubmapInfo = .{
4848	.base_addr = address,
4849	.tag = tag,
4850	.info = undefined,
4851	};
4852	switch (tag) {
4853	.short => info.info = .{ .short = undefined },
4854	.full => info.info = .{ .full = undefined },
4855	}
4856	var nesting = nesting_depth;
4857	var base_len: std.c.mach_vm_size_t = if (len == 1) 2 else len;
4858	var count: std.c.mach_msg_type_number_t = switch (tag) {
4859	.short => std.c.VM.REGION.SUBMAP_SHORT_INFO_COUNT_64,
4860	.full => std.c.VM.REGION.SUBMAP_INFO_COUNT_64,
4861	};
4862	switch (getKernError(std.c.mach_vm_region_recurse(
4863	task.port,
4864	&info.base_addr,
4865	&base_len,
4866	&nesting,
4867	switch (tag) {
4868	.short => @as(std.c.vm_region_recurse_info_t, @ptrCast(&info.info.short)),
4869	.full => @as(std.c.vm_region_recurse_info_t, @ptrCast(&info.info.full)),
4870	},
4871	&count,
4872	))) {
4873	.SUCCESS => return info,
4874	.FAILURE => return error.PermissionDenied,
4875	else => |err| return unexpectedKernError(err),
4876	}
4877	}
4878
4879	pub fn getCurrProtection(task: MachTask, address: u64, len: usize) MachError!std.c.vm_prot_t {
4880	const info = try task.getRegionSubmapInfo(address, len, 0, .short);
4881	return info.info.short.protection;
4882	}
4883
4884	pub fn setMaxProtection(task: MachTask, address: u64, len: usize, prot: std.c.vm_prot_t) MachError!void {
4885	return task.setProtectionImpl(address, len, true, prot);
4886	}
4887
4888	pub fn setCurrProtection(task: MachTask, address: u64, len: usize, prot: std.c.vm_prot_t) MachError!void {
4889	return task.setProtectionImpl(address, len, false, prot);
4890	}
4891
4892	fn setProtectionImpl(task: MachTask, address: u64, len: usize, set_max: bool, prot: std.c.vm_prot_t) MachError!void {
4893	switch (getKernError(std.c.mach_vm_protect(task.port, address, len, @intFromBool(set_max), prot))) {
4894	.SUCCESS => return,
4895	.FAILURE => return error.PermissionDenied,
4896	else => |err| return unexpectedKernError(err),
4897	}
4898	}
4899
4900	/// Will write to VM even if current protection attributes specifically prohibit
4901	/// us from doing so, by temporarily setting protection level to a level with VM_PROT_COPY
4902	/// variant, and resetting after a successful or unsuccessful write.
4903	pub fn writeMemProtected(task: MachTask, address: u64, buf: []const u8, arch: std.Target.Cpu.Arch) MachError!usize {
4904	const curr_prot = try task.getCurrProtection(address, buf.len);
4905	try task.setCurrProtection(
4906	address,
4907	buf.len,
4908	.{ .READ = true, .WRITE = true, .COPY = true },
4909	);
4910	defer {
4911	task.setCurrProtection(address, buf.len, curr_prot) catch {};
4912	}
4913	return task.writeMem(address, buf, arch);
4914	}
4915
4916	pub fn writeMem(task: MachTask, address: u64, buf: []const u8, arch: std.Target.Cpu.Arch) MachError!usize {
4917	const count = buf.len;
4918	var total_written: usize = 0;
4919	var curr_addr = address;
4920	const page_size = try MachTask.getPageSize(task); // TODO we probably can assume value here
4921	var out_buf = buf[0..];
4922
4923	while (total_written < count) {
4924	const curr_size = maxBytesLeftInPage(page_size, curr_addr, count - total_written);
4925	switch (getKernError(std.c.mach_vm_write(
4926	task.port,
4927	curr_addr,
4928	@intFromPtr(out_buf.ptr),
4929	@as(std.c.mach_msg_type_number_t, @intCast(curr_size)),
4930	))) {
4931	.SUCCESS => {},
4932	.FAILURE => return error.PermissionDenied,
4933	else => |err| return unexpectedKernError(err),
4934	}
4935
4936	switch (arch) {
4937	.aarch64 => {
4938	var mattr_value: std.c.vm_machine_attribute_val_t = std.c.MATTR.VAL_CACHE_FLUSH;
4939	switch (getKernError(std.c.vm_machine_attribute(
4940	task.port,
4941	curr_addr,
4942	curr_size,
4943	std.c.MATTR.CACHE,
4944	&mattr_value,
4945	))) {
4946	.SUCCESS => {},
4947	.FAILURE => return error.PermissionDenied,
4948	else => |err| return unexpectedKernError(err),
4949	}
4950	},
4951	.x86_64 => {},
4952	else => unreachable,
4953	}
4954
4955	out_buf = out_buf[curr_size..];
4956	total_written += curr_size;
4957	curr_addr += curr_size;
4958	}
4959
4960	return total_written;
4961	}
4962
4963	pub fn readMem(task: MachTask, address: u64, buf: []u8) MachError!usize {
4964	const count = buf.len;
4965	var total_read: usize = 0;
4966	var curr_addr = address;
4967	const page_size = try MachTask.getPageSize(task); // TODO we probably can assume value here
4968	var out_buf = buf[0..];
4969
4970	while (total_read < count) {
4971	const curr_size = maxBytesLeftInPage(page_size, curr_addr, count - total_read);
4972	var curr_bytes_read: std.c.mach_msg_type_number_t = 0;
4973	var vm_memory: std.c.vm_offset_t = undefined;
4974	switch (getKernError(std.c.mach_vm_read(task.port, curr_addr, curr_size, &vm_memory, &curr_bytes_read))) {
4975	.SUCCESS => {},
4976	.FAILURE => return error.PermissionDenied,
4977	else => |err| return unexpectedKernError(err),
4978	}
4979
4980	@memcpy(out_buf[0..curr_bytes_read], @as([*]const u8, @ptrFromInt(vm_memory)));
4981	_ = std.c.vm_deallocate(std.c.mach_task_self(), vm_memory, curr_bytes_read);
4982
4983	out_buf = out_buf[curr_bytes_read..];
4984	curr_addr += curr_bytes_read;
4985	total_read += curr_bytes_read;
4986	}
4987
4988	return total_read;
4989	}
4990
4991	fn maxBytesLeftInPage(page_size: usize, address: u64, count: usize) usize {
4992	var left = count;
4993	if (page_size > 0) {
4994	const page_offset = address % page_size;
4995	const bytes_left_in_page = page_size - page_offset;
4996	if (count > bytes_left_in_page) {
4997	left = bytes_left_in_page;
4998	}
4999	}
5000	return left;
5001	}
5002
5003	fn getPageSize(task: MachTask) MachError!usize {
5004	if (task.isValid()) {
5005	var info_count = std.c.TASK_VM_INFO_COUNT;
5006	var vm_info: std.c.task_vm_info_data_t = undefined;
5007	switch (getKernError(std.c.task_info(
5008	task.port,
5009	std.c.TASK_VM_INFO,
5010	@as(std.c.task_info_t, @ptrCast(&vm_info)),
5011	&info_count,
5012	))) {
5013	.SUCCESS => return @as(usize, @intCast(vm_info.page_size)),
5014	else => {},
5015	}
5016	}
5017	var page_size: std.c.vm_size_t = undefined;
5018	switch (getKernError(std.c._host_page_size(std.c.mach_host_self(), &page_size))) {
5019	.SUCCESS => return page_size,
5020	else => |err| return unexpectedKernError(err),
5021	}
5022	}
5023
5024	pub fn basicTaskInfo(task: MachTask) MachError!std.c.mach_task_basic_info {
5025	var info: std.c.mach_task_basic_info = undefined;
5026	var count = std.c.MACH_TASK_BASIC_INFO_COUNT;
5027	switch (getKernError(std.c.task_info(
5028	task.port,
5029	std.c.MACH_TASK_BASIC_INFO,
5030	@as(std.c.task_info_t, @ptrCast(&info)),
5031	&count,
5032	))) {
5033	.SUCCESS => return info,
5034	else => |err| return unexpectedKernError(err),
5035	}
5036	}
5037
5038	pub fn @"resume"(task: MachTask) MachError!void {
5039	switch (getKernError(std.c.task_resume(task.port))) {
5040	.SUCCESS => {},
5041	else => |err| return unexpectedKernError(err),
5042	}
5043	}
5044
5045	pub fn @"suspend"(task: MachTask) MachError!void {
5046	switch (getKernError(std.c.task_suspend(task.port))) {
5047	.SUCCESS => {},
5048	else => |err| return unexpectedKernError(err),
5049	}
5050	}
5051
5052	const ThreadList = struct {
5053	buf: []MachThread,
5054
5055	pub fn deinit(list: ThreadList) void {
5056	const self_task = machTaskForSelf();
5057	_ = std.c.vm_deallocate(
5058	self_task.port,
5059	@intFromPtr(list.buf.ptr),
5060	@as(std.c.vm_size_t, @intCast(list.buf.len * @sizeOf(std.c.mach_port_t))),
5061	);
5062	}
5063	};
5064
5065	pub fn getThreads(task: MachTask) MachError!ThreadList {
5066	var thread_list: std.c.mach_port_array_t = undefined;
5067	var thread_count: std.c.mach_msg_type_number_t = undefined;
5068	switch (getKernError(std.c.task_threads(task.port, &thread_list, &thread_count))) {
5069	.SUCCESS => return ThreadList{ .buf = @as([*]MachThread, @ptrCast(thread_list))[0..thread_count] },
5070	else => |err| return unexpectedKernError(err),
5071	}
5072	}
5073	};
5074
5075	pub const MachThread = extern struct {
5076	port: std.c.mach_port_t,
5077
5078	pub fn isValid(thread: MachThread) bool {
5079	return thread.port != std.c.THREAD_NULL;
5080	}
5081
5082	pub fn getBasicInfo(thread: MachThread) MachError!std.c.thread_basic_info {
5083	var info: std.c.thread_basic_info = undefined;
5084	var count = std.c.THREAD_BASIC_INFO_COUNT;
5085	switch (getKernError(std.c.thread_info(
5086	thread.port,
5087	std.c.THREAD_BASIC_INFO,
5088	@as(std.c.thread_info_t, @ptrCast(&info)),
5089	&count,
5090	))) {
5091	.SUCCESS => return info,
5092	else => |err| return unexpectedKernError(err),
5093	}
5094	}
5095
5096	pub fn getIdentifierInfo(thread: MachThread) MachError!std.c.thread_identifier_info {
5097	var info: std.c.thread_identifier_info = undefined;
5098	var count = std.c.THREAD_IDENTIFIER_INFO_COUNT;
5099	switch (getKernError(std.c.thread_info(
5100	thread.port,
5101	std.c.THREAD_IDENTIFIER_INFO,
5102	@as(std.c.thread_info_t, @ptrCast(&info)),
5103	&count,
5104	))) {
5105	.SUCCESS => return info,
5106	else => |err| return unexpectedKernError(err),
5107	}
5108	}
5109	};
5110
5111	pub fn machTaskForPid(pid: std.c.pid_t) MachError!MachTask {
5112	var port: std.c.mach_port_name_t = undefined;
5113	switch (getKernError(std.c.task_for_pid(std.c.mach_task_self(), pid, &port))) {
5114	.SUCCESS => {},
5115	.FAILURE => return error.PermissionDenied,
5116	else => |err| return unexpectedKernError(err),
5117	}
5118	return MachTask{ .port = port };
5119	}
5120
5121	pub fn machTaskForSelf() MachTask {
5122	return .{ .port = std.c.mach_task_self() };
5123	}
5124
5125	pub fn getKernError(err: std.c.kern_return_t) KernE {
5126	return @as(KernE, @fromBackingInt(@intCast(@as(u32, @truncate(@as(usize, @intCast(err)))))));
5127	}
5128
5129	pub fn unexpectedKernError(err: KernE) std.posix.UnexpectedError {
5130	if (std.options.unexpected_error_tracing) {
5131	std.debug.print("unexpected error: {d}\n", .{@backingInt(err)});
5132	std.debug.dumpCurrentStackTrace(.{});
5133	}
5134	return error.Unexpected;
5135	}
5136
5137	/// Kernel return values
5138	pub const KernE = enum(u32) {
5139	SUCCESS = 0,
5140	/// Specified address is not currently valid
5141	INVALID_ADDRESS = 1,
5142	/// Specified memory is valid, but does not permit the
5143	/// required forms of access.
5144	PROTECTION_FAILURE = 2,
5145	/// The address range specified is already in use, or
5146	/// no address range of the size specified could be
5147	/// found.
5148	NO_SPACE = 3,
5149	/// The function requested was not applicable to this
5150	/// type of argument, or an argument is invalid
5151	INVALID_ARGUMENT = 4,
5152	/// The function could not be performed. A catch-all.
5153	FAILURE = 5,
5154	/// A system resource could not be allocated to fulfill
5155	/// this request. This failure may not be permanent.
5156	RESOURCE_SHORTAGE = 6,
5157	/// The task in question does not hold receive rights
5158	/// for the port argument.
5159	NOT_RECEIVER = 7,
5160	/// Bogus access restriction.
5161	NO_ACCESS = 8,
5162	/// During a page fault, the target address refers to a
5163	/// memory object that has been destroyed. This
5164	/// failure is permanent.
5165	MEMORY_FAILURE = 9,
5166	/// During a page fault, the memory object indicated
5167	/// that the data could not be returned. This failure
5168	/// may be temporary; future attempts to access this
5169	/// same data may succeed, as defined by the memory
5170	/// object.
5171	MEMORY_ERROR = 10,
5172	/// The receive right is already a member of the portset.
5173	ALREADY_IN_SET = 11,
5174	/// The receive right is not a member of a port set.
5175	NOT_IN_SET = 12,
5176	/// The name already denotes a right in the task.
5177	NAME_EXISTS = 13,
5178	/// The operation was aborted. Ipc code will
5179	/// catch this and reflect it as a message error.
5180	ABORTED = 14,
5181	/// The name doesn't denote a right in the task.
5182	INVALID_NAME = 15,
5183	/// Target task isn't an active task.
5184	INVALID_TASK = 16,
5185	/// The name denotes a right, but not an appropriate right.
5186	INVALID_RIGHT = 17,
5187	/// A blatant range error.
5188	INVALID_VALUE = 18,
5189	/// Operation would overflow limit on user-references.
5190	UREFS_OVERFLOW = 19,
5191	/// The supplied (port) capability is improper.
5192	INVALID_CAPABILITY = 20,
5193	/// The task already has send or receive rights
5194	/// for the port under another name.
5195	RIGHT_EXISTS = 21,
5196	/// Target host isn't actually a host.
5197	INVALID_HOST = 22,
5198	/// An attempt was made to supply "precious" data
5199	/// for memory that is already present in a
5200	/// memory object.
5201	MEMORY_PRESENT = 23,
5202	/// A page was requested of a memory manager via
5203	/// memory_object_data_request for an object using
5204	/// a MEMORY_OBJECT_COPY_CALL strategy, with the
5205	/// VM_PROT_WANTS_COPY flag being used to specify
5206	/// that the page desired is for a copy of the
5207	/// object, and the memory manager has detected
5208	/// the page was pushed into a copy of the object
5209	/// while the kernel was walking the shadow chain
5210	/// from the copy to the object. This error code
5211	/// is delivered via memory_object_data_error
5212	/// and is handled by the kernel (it forces the
5213	/// kernel to restart the fault). It will not be
5214	/// seen by users.
5215	MEMORY_DATA_MOVED = 24,
5216	/// A strategic copy was attempted of an object
5217	/// upon which a quicker copy is now possible.
5218	/// The caller should retry the copy using
5219	/// vm_object_copy_quickly. This error code
5220	/// is seen only by the kernel.
5221	MEMORY_RESTART_COPY = 25,
5222	/// An argument applied to assert processor set privilege
5223	/// was not a processor set control port.
5224	INVALID_PROCESSOR_SET = 26,
5225	/// The specified scheduling attributes exceed the thread's
5226	/// limits.
5227	POLICY_LIMIT = 27,
5228	/// The specified scheduling policy is not currently
5229	/// enabled for the processor set.
5230	INVALID_POLICY = 28,
5231	/// The external memory manager failed to initialize the
5232	/// memory object.
5233	INVALID_OBJECT = 29,
5234	/// A thread is attempting to wait for an event for which
5235	/// there is already a waiting thread.
5236	ALREADY_WAITING = 30,
5237	/// An attempt was made to destroy the default processor
5238	/// set.
5239	DEFAULT_SET = 31,
5240	/// An attempt was made to fetch an exception port that is
5241	/// protected, or to abort a thread while processing a
5242	/// protected exception.
5243	EXCEPTION_PROTECTED = 32,
5244	/// A ledger was required but not supplied.
5245	INVALID_LEDGER = 33,
5246	/// The port was not a memory cache control port.
5247	INVALID_MEMORY_CONTROL = 34,
5248	/// An argument supplied to assert security privilege
5249	/// was not a host security port.
5250	INVALID_SECURITY = 35,
5251	/// thread_depress_abort was called on a thread which
5252	/// was not currently depressed.
5253	NOT_DEPRESSED = 36,
5254	/// Object has been terminated and is no longer available
5255	TERMINATED = 37,
5256	/// Lock set has been destroyed and is no longer available.
5257	LOCK_SET_DESTROYED = 38,
5258	/// The thread holding the lock terminated before releasing
5259	/// the lock
5260	LOCK_UNSTABLE = 39,
5261	/// The lock is already owned by another thread
5262	LOCK_OWNED = 40,
5263	/// The lock is already owned by the calling thread
5264	LOCK_OWNED_SELF = 41,
5265	/// Semaphore has been destroyed and is no longer available.
5266	SEMAPHORE_DESTROYED = 42,
5267	/// Return from RPC indicating the target server was
5268	/// terminated before it successfully replied
5269	RPC_SERVER_TERMINATED = 43,
5270	/// Terminate an orphaned activation.
5271	RPC_TERMINATE_ORPHAN = 44,
5272	/// Allow an orphaned activation to continue executing.
5273	RPC_CONTINUE_ORPHAN = 45,
5274	/// Empty thread activation (No thread linked to it)
5275	NOT_SUPPORTED = 46,
5276	/// Remote node down or inaccessible.
5277	NODE_DOWN = 47,
5278	/// A signalled thread was not actually waiting.
5279	NOT_WAITING = 48,
5280	/// Some thread-oriented operation (semaphore_wait) timed out
5281	OPERATION_TIMED_OUT = 49,
5282	/// During a page fault, indicates that the page was rejected
5283	/// as a result of a signature check.
5284	CODESIGN_ERROR = 50,
5285	/// The requested property cannot be changed at this time.
5286	POLICY_STATIC = 51,
5287	/// The provided buffer is of insufficient size for the requested data.
5288	INSUFFICIENT_BUFFER_SIZE = 52,
5289	/// Denied by security policy
5290	DENIED = 53,
5291	/// The KC on which the function is operating is missing
5292	MISSING_KC = 54,
5293	/// The KC on which the function is operating is invalid
5294	INVALID_KC = 55,
5295	/// A search or query operation did not return a result
5296	NOT_FOUND = 56,
5297	_,
5298	};
5299
5300	fn createThunks(macho_file: *MachO, sect_id: u8) !void {
5301	const tracy = trace(@src());
5302	defer tracy.end();
5303
5304	const gpa = macho_file.base.comp.gpa;
5305	const slice = macho_file.sections.slice();
5306	const header = &slice.items(.header)[sect_id];
5307	const thnks = &slice.items(.thunks)[sect_id];
5308	const atoms = slice.items(.atoms)[sect_id].items;
5309	assert(atoms.len > 0);
5310
5311	for (atoms) |ref| {
5312	ref.getAtom(macho_file).?.value = @bitCast(@as(i64, -1));
5313	}
5314
5315	var i: usize = 0;
5316	while (i < atoms.len) {
5317	const start = i;
5318	const start_atom = atoms[start].getAtom(macho_file).?;
5319	assert(start_atom.isAlive());
5320	start_atom.value = advanceSection(header, start_atom.size, start_atom.alignment);
5321	i += 1;
5322
5323	while (i < atoms.len and
5324	header.size - start_atom.value < max_allowed_distance) : (i += 1)
5325	{
5326	const atom = atoms[i].getAtom(macho_file).?;
5327	assert(atom.isAlive());
5328	atom.value = advanceSection(header, atom.size, atom.alignment);
5329	}
5330
5331	// Insert a thunk at the group end
5332	const thunk_index = try macho_file.addThunk();
5333	const thunk = macho_file.getThunk(thunk_index);
5334	thunk.out_n_sect = sect_id;
5335	try thnks.append(gpa, thunk_index);
5336
5337	// Scan relocs in the group and create trampolines for any unreachable callsite
5338	try scanThunkRelocs(thunk_index, gpa, atoms[start..i], macho_file);
5339	thunk.value = advanceSection(header, thunk.size(), .@"4");
5340
5341	log.debug("thunk({d}) : {f}", .{ thunk_index, thunk.fmt(macho_file) });
5342	}
5343	}
5344
5345	fn advanceSection(sect: *macho.section_64, adv_size: u64, alignment: Atom.Alignment) u64 {
5346	const offset = alignment.forward(sect.size);
5347	const padding = offset - sect.size;
5348	sect.size += padding + adv_size;
5349	sect.@"align" = @max(sect.@"align", alignment.toLog2Units());
5350	return offset;
5351	}
5352
5353	fn scanThunkRelocs(thunk_index: Thunk.Index, gpa: Allocator, atoms: []const MachO.Ref, macho_file: *MachO) !void {
5354	const tracy = trace(@src());
5355	defer tracy.end();
5356
5357	const thunk = macho_file.getThunk(thunk_index);
5358
5359	for (atoms) |ref| {
5360	const atom = ref.getAtom(macho_file).?;
5361	log.debug("atom({d}) {s}", .{ atom.atom_index, atom.getName(macho_file) });
5362	for (atom.getRelocs(macho_file)) |rel| {
5363	if (rel.type != .branch) continue;
5364	if (isReachable(atom, rel, macho_file)) continue;
5365	try thunk.symbols.put(gpa, rel.getTargetSymbolRef(atom.*, macho_file), {});
5366	}
5367	atom.addExtra(.{ .thunk = thunk_index }, macho_file);
5368	}
5369	}
5370
5371	fn isReachable(atom: *const Atom, rel: Relocation, macho_file: *MachO) bool {
5372	const target = rel.getTargetSymbol(atom.*, macho_file);
5373	if (target.getSectionFlags().stubs or target.getSectionFlags().objc_stubs) return false;
5374	if (atom.out_n_sect != target.getOutputSectionIndex(macho_file)) return false;
5375	const target_atom = target.getAtom(macho_file).?;
5376	if (target_atom.value == @as(u64, @bitCast(@as(i64, -1)))) return false;
5377	const saddr = @as(i64, @intCast(atom.getAddress(macho_file))) + @as(i64, @intCast(rel.offset - atom.off));
5378	const taddr: i64 = @intCast(rel.getTargetAddress(atom.*, macho_file));
5379	_ = math.cast(i28, taddr + rel.addend - saddr) orelse return false;
5380	return true;
5381	}
5382
5383	pub fn pwriteAll(macho_file: *MachO, bytes: []const u8, offset: u64) error{AlreadyReported}!void {
5384	const comp = macho_file.base.comp;
5385	const io = comp.io;
5386	const diags = &comp.link_diags;
5387	macho_file.base.file.?.writePositionalAll(io, bytes, offset) catch |err|
5388	return diags.fail("failed to write: {t}", .{err});
5389	}
5390
5391	pub fn setLength(macho_file: *MachO, length: u64) error{AlreadyReported}!void {
5392	const comp = macho_file.base.comp;
5393	const io = comp.io;
5394	const diags = &comp.link_diags;
5395	macho_file.base.file.?.setLength(io, length) catch |err|
5396	return diags.fail("failed to set file end pos: {t}", .{err});
5397	}
5398
5399	pub fn cast(macho_file: *MachO, comptime T: type, x: anytype) error{AlreadyReported}!T {
5400	return std.math.cast(T, x) orelse {
5401	const comp = macho_file.base.comp;
5402	const diags = &comp.link_diags;
5403	return diags.fail("encountered {d}, overflowing {d}-bit value", .{ x, @bitSizeOf(T) });
5404	};
5405	}
5406
5407	pub fn alignPow(macho_file: *MachO, x: u32) error{AlreadyReported}!u32 {
5408	const result, const ov = @shlWithOverflow(@as(u32, 1), try cast(macho_file, u5, x));
5409	if (ov != 0) {
5410	const comp = macho_file.base.comp;
5411	const diags = &comp.link_diags;
5412	return diags.fail("alignment overflow", .{});
5413	}
5414	return result;
5415	}
5416
5417	pub fn needsEncryptionInfo(macho_file: *MachO) bool {
5418	const target = macho_file.getTarget();
5419	return switch (target.os.tag) {
5420	.ios,
5421	.tvos,
5422	.visionos,
5423	.watchos,
5424	=> target.abi != .simulator,
5425	else => false,
5426	};
5427	}
5428
5429	/// Branch instruction has 26 bits immediate but is 4 byte aligned.
5430	const jump_bits = @bitSizeOf(i28);
5431	const max_distance = (1 << (jump_bits - 1));
5432
5433	/// A branch will need an extender if its target is larger than
5434	/// `2^(jump_bits - 1) - margin` where margin is some arbitrary number.
5435	/// mold uses 5MiB margin, while ld64 uses 4MiB margin. We will follow mold
5436	/// and assume margin to be 5MiB.
5437	const max_allowed_distance = max_distance - 0x500_000;
5438
5439	const MachO = @This();
5440	const build_options = @import("build_options");
5441	const builtin = @import("builtin");
5442
5443	const std = @import("std");
5444	const Io = std.Io;
5445	const assert = std.debug.assert;
5446	const fs = std.fs;
5447	const log = std.log.scoped(.link);
5448	const state_log = std.log.scoped(.link_state);
5449	const macho = std.macho;
5450	const math = std.math;
5451	const mem = std.mem;
5452	const meta = std.meta;
5453	const Writer = std.Io.Writer;
5454	const AtomicBool = std.atomic.Value(bool);
5455	const Cache = std.Build.Cache;
5456	const Hash = std.hash.Wyhash;
5457	const Md5 = std.crypto.hash.Md5;
5458	const Allocator = std.mem.Allocator;
5459
5460	const aarch64 = codegen.aarch64.encoding;
5461	const bind = @import("MachO/dyld_info/bind.zig");
5462	const calcUuid = @import("MachO/uuid.zig").calcUuid;
5463	const codegen = @import("../codegen.zig");
5464	const dead_strip = @import("MachO/dead_strip.zig");
5465	const eh_frame = @import("MachO/eh_frame.zig");
5466	const fat = @import("MachO/fat.zig");
5467	const link = @import("../link.zig");
5468	const load_commands = @import("MachO/load_commands.zig");
5469	const relocatable = @import("MachO/relocatable.zig");
5470	const tapi = @import("tapi.zig");
5471	const target_util = @import("../target.zig");
5472	const trace = @import("../tracy.zig").trace;
5473	const synthetic = @import("MachO/synthetic.zig");
5474
5475	const Alignment = Atom.Alignment;
5476	const Archive = @import("MachO/Archive.zig");
5477	const Bind = bind.Bind;
5478	const CodeSignature = @import("MachO/CodeSignature.zig");
5479	const Compilation = @import("../Compilation.zig");
5480	const DataInCode = synthetic.DataInCode;
5481	const Directory = Cache.Directory;
5482	const Dylib = @import("MachO/Dylib.zig");
5483	const ExportTrie = @import("MachO/dyld_info/Trie.zig");
5484	const Path = Cache.Path;
5485	const File = @import("MachO/file.zig").File;
5486	const GotSection = synthetic.GotSection;
5487	const Indsymtab = synthetic.Indsymtab;
5488	const InternalObject = @import("MachO/InternalObject.zig");
5489	const ObjcStubsSection = synthetic.ObjcStubsSection;
5490	const Object = @import("MachO/Object.zig");
5491	const LazyBind = bind.LazyBind;
5492	const LaSymbolPtrSection = synthetic.LaSymbolPtrSection;
5493	const Zcu = @import("../Zcu.zig");
5494	const InternPool = @import("../InternPool.zig");
5495	const Rebase = @import("MachO/dyld_info/Rebase.zig");
5496	const StringTable = @import("StringTable.zig");
5497	const StubsSection = synthetic.StubsSection;
5498	const StubsHelperSection = synthetic.StubsHelperSection;
5499	const Symbol = @import("MachO/Symbol.zig");
5500	const Thunk = @import("MachO/Thunk.zig");
5501	const TlvPtrSection = synthetic.TlvPtrSection;
5502	const Value = @import("../Value.zig");
5503	const UnwindInfo = @import("MachO/UnwindInfo.zig");
5504	const WeakBind = bind.WeakBind;
5505	const ZigObject = @import("MachO/ZigObject.zig");