Commit bd99a87dc224b7d84e764fc2a8a8f4e3068078b3 | zig

author	Jakub Konka <kubkon@jakubkonka.com> 2020-12-27 09:30:03+01:00
committer	Jakub Konka <kubkon@jakubkonka.com> 2020-12-31 10:19:04+01:00
log	bd99a87dc224b7d84e764fc2a8a8f4e3068078b3
tree	2500fcf9f2e04b1ab192814bfed4b7884a0b42a6
parent	0ff56e8bb14273fa8abe4503855e9f53d699c8cd

macho: create dSym bundle next to final artefact

macOS requires the debug symbols to either be part of the intermediate
object file `whatever.o` or a companion `whatever.dSym` bundle. The
former case seems ill-suited for our needs since it subscribes to
the old-fashioned compilation strategy using intermediate compilation
units; the latter is what we need however on macOS the debug symbols
unlike in Elf are not part of the final artefact; rather they sit
next to it in its own Mach-O file.

2 files changed, 62 insertions(+), 0 deletions(-)

src
- link
  - MachO.zig
  - MachO
    DebugSymbols.zig

src/link/MachO.zig+22

...	...	@@ -3,6 +3,7 @@ const MachO = @This();
3	3	const std = @import("std");
4	4	const Allocator = std.mem.Allocator;
5	5	const assert = std.debug.assert;
	6	const fmt = std.fmt;
6	7	const fs = std.fs;
7	8	const log = std.log.scoped(.link);
8	9	const macho = std.macho;
...	...	@@ -21,6 +22,7 @@ const File = link.File;
21	22	const Cache = @import("../Cache.zig");
22	23	const target_util = @import("../target.zig");
23	24
	25	const DebugSymbols = @import("MachO/DebugSymbols.zig");
24	26	const Trie = @import("MachO/Trie.zig");
25	27	const CodeSignature = @import("MachO/CodeSignature.zig");
26	28
...	...	@@ -31,6 +33,9 @@ pub const base_tag: File.Tag = File.Tag.macho;
31	33
32	34	base: File,
33	35
	36	/// Debug symbols bundle (or dSym).
	37	d_sym: ?DebugSymbols = null,
	38
34	39	/// Page size is dependent on the target cpu architecture.
35	40	/// For x86_64 that's 4KB, whereas for aarch64, that's 16KB.
36	41	page_size: u16,
...	...	@@ -264,6 +269,20 @@ pub fn openPath(allocator: *Allocator, sub_path: []const u8, options: link.Optio
264	269
265	270	self.base.file = file;
266	271
	272	// Create dSym bundle.
	273	const d_sym_path = try fmt.allocPrint(allocator, "{}.dSym/Contents/Resources/DWARF/", .{sub_path});
	274	defer allocator.free(d_sym_path);
	275	var d_sym_bundle = try options.emit.?.directory.handle.makeOpenPath(d_sym_path, .{});
	276	defer d_sym_bundle.close();
	277	const d_sym_file = try d_sym_bundle.createFile(sub_path, .{
	278	.truncate = false,
	279	.read = true,
	280	});
	281	self.d_sym = .{
	282	.base = self,
	283	.file = d_sym_file,
	284	};
	285
267	286	// Index 0 is always a null symbol.
268	287	try self.local_symbols.append(allocator, .{
269	288	.n_strx = 0,
...	...	@@ -943,6 +962,9 @@ fn darwinArchString(arch: std.Target.Cpu.Arch) []const u8 {
943	962	}
944	963
945	964	pub fn deinit(self: *MachO) void {
	965	if (self.d_sym) \|*ds\| {
	966	ds.deinit(self.base.allocator);
	967	}
946	968	self.binding_info_table.deinit(self.base.allocator);
947	969	self.lazy_binding_info_table.deinit(self.base.allocator);
948	970	self.pie_fixups.deinit(self.base.allocator);

src/link/MachO/DebugSymbols.zig created+40

...	...	@@ -0,0 +1,40 @@
	1	const DebugSymbols = @This();
	2
	3	const std = @import("std");
	4	const fs = std.fs;
	5	const macho = std.macho;
	6	const mem = std.mem;
	7	const DW = std.dwarf;
	8	const leb = std.leb;
	9	const Allocator = mem.Allocator;
	10
	11	const MachO = @import("../MachO.zig");
	12
	13	usingnamespace @import("commands.zig");
	14
	15	base: *MachO,
	16	file: fs.File,
	17
	18	/// Mach header
	19	header: ?macho.mach_header_64 = null,
	20
	21	/// Table of all load commands
	22	load_commands: std.ArrayListUnmanaged(LoadCommand) = .{},
	23	/// __PAGEZERO segment
	24	pagezero_segment_cmd_index: ?u16 = null,
	25	/// __TEXT segment
	26	text_segment_cmd_index: ?u16 = null,
	27	/// __DWARF segment
	28	dwarf_segment_cmd_index: ?u16 = null,
	29	/// __DATA segment
	30	data_segment_cmd_index: ?u16 = null,
	31	/// __LINKEDIT segment
	32	linkedit_segment_cmd_index: ?u16 = null,
	33	/// Symbol table
	34	symtab_cmd_index: ?u16 = null,
	35	/// UUID load command
	36	uuid_cmd_index: ?u16 = null,
	37
	38	pub fn deinit(self: DebugSymbols, allocator: Allocator) void {
	39	self.file.close();
	40	}