Commit 6461b9516371d22d347c27b5fcd2e8c22fafd03d | zig

author	Jakub Konka <kubkon@jakubkonka.com> 2021-05-14 19:20:21+02:00
committer	Jakub Konka <kubkon@jakubkonka.com> 2021-05-16 08:12:29+02:00
log	6461b9516371d22d347c27b5fcd2e8c22fafd03d
tree	4d11bd6cfeca70ff1f82b1318ef75c8722695278
parent	d98e39fa6864f287bc50f265f98b7195849afa68

macho: fix DWARF in dSYM and sym naming more consistent

* Advance line and PC prior to ending sequence in debug line program
  for a fn_decl. This is equivalent to closing scope in the debugger
  and without it, the debugger will not map source-to-address info
  as a result will not print the source when breaking at a symbol.
* Fix debug aranges sentinels to be of the size as the actual tuple
  descriptor (assuming segment selector to be ommitted). In summary,
  the sentinels were 32bit 0s, whereas they ought to be 64bit 0s.
* Make naming of symbols in the binary more consistent by prefixing
  each symbol name with an underscore '_'.

3 files changed, 53 insertions(+), 15 deletions(-)

src
- link
  - MachO.zig
  - MachO
    DebugSymbols.zig
test
- stage2
  - darwin.zig

src/link/MachO.zig+18-6

...	...	@@ -362,8 +362,8 @@ pub fn openPath(allocator: *Allocator, sub_path: []const u8, options: link.Optio
362	362
363	363	self.base.file = file;
364	364
365		// Create dSYM bundle.
366	365	if (!options.strip and options.module != null) {
	366	// Create dSYM bundle.
367	367	const dir = options.module.?.zig_cache_artifact_directory;
368	368	log.debug("creating {s}.dSYM bundle in {s}", .{ sub_path, dir.path });
369	369
...	...	@@ -1223,7 +1223,11 @@ pub fn updateDecl(self: MachO, module: Module, decl: *Module.Decl) !void {
1223	1223	self.shrinkTextBlock(&decl.link.macho, code.len);
1224	1224	}
1225	1225	decl.link.macho.size = code.len;
1226		symbol.n_strx = try self.updateString(symbol.n_strx, mem.spanZ(decl.name));
	1226
	1227	const new_name = try std.fmt.allocPrint(self.base.allocator, "_{s}", .{mem.spanZ(decl.name)});
	1228	defer self.base.allocator.free(new_name);
	1229
	1230	symbol.n_strx = try self.updateString(symbol.n_strx, new_name);
1227	1231	symbol.n_type = macho.N_SECT;
1228	1232	symbol.n_sect = @intCast(u8, self.text_section_index.?) + 1;
1229	1233	symbol.n_desc = 0;
...	...	@@ -1232,7 +1236,9 @@ pub fn updateDecl(self: MachO, module: Module, decl: *Module.Decl) !void {
1232	1236	if (self.d_sym) \|*ds\|
1233	1237	try ds.writeLocalSymbol(decl.link.macho.local_sym_index);
1234	1238	} else {
1235		const decl_name = mem.spanZ(decl.name);
	1239	const decl_name = try std.fmt.allocPrint(self.base.allocator, "_{s}", .{mem.spanZ(decl.name)});
	1240	defer self.base.allocator.free(decl_name);
	1241
1236	1242	const name_str_index = try self.makeString(decl_name);
1237	1243	const addr = try self.allocateTextBlock(&decl.link.macho, code.len, required_alignment);
1238	1244
...	...	@@ -1371,6 +1377,9 @@ pub fn updateDeclExports(
1371	1377	const decl_sym = &self.locals.items[decl.link.macho.local_sym_index];
1372	1378
1373	1379	for (exports) \|exp\| {
	1380	const exp_name = try std.fmt.allocPrint(self.base.allocator, "_{s}", .{exp.options.name});
	1381	defer self.base.allocator.free(exp_name);
	1382
1374	1383	if (exp.options.section) \|section_name\| {
1375	1384	if (!mem.eql(u8, section_name, "__text")) {
1376	1385	try module.failed_exports.ensureCapacity(module.gpa, module.failed_exports.items().len + 1);
...	...	@@ -1398,7 +1407,7 @@ pub fn updateDeclExports(
1398	1407	// Otherwise, don't do anything since we already have all the flags
1399	1408	// set that we need for global (strong) linkage.
1400	1409	// n_type == N_SECT \| N_EXT
1401		if (mem.eql(u8, exp.options.name, "_main")) {
	1410	if (mem.eql(u8, exp_name, "_main")) {
1402	1411	self.entry_addr = decl_sym.n_value;
1403	1412	}
1404	1413	},
...	...	@@ -1420,14 +1429,14 @@ pub fn updateDeclExports(
1420	1429	if (exp.link.macho.sym_index) \|i\| {
1421	1430	const sym = &self.globals.items[i];
1422	1431	sym.* = .{
1423		.n_strx = try self.updateString(sym.n_strx, exp.options.name),
	1432	.n_strx = try self.updateString(sym.n_strx, exp_name),
1424	1433	.n_type = n_type,
1425	1434	.n_sect = @intCast(u8, self.text_section_index.?) + 1,
1426	1435	.n_desc = n_desc,
1427	1436	.n_value = decl_sym.n_value,
1428	1437	};
1429	1438	} else {
1430		const name_str_index = try self.makeString(exp.options.name);
	1439	const name_str_index = try self.makeString(exp_name);
1431	1440	const i = if (self.globals_free_list.popOrNull()) \|i\| i else blk: {
1432	1441	_ = self.globals.addOneAssumeCapacity();
1433	1442	self.export_info_dirty = true;
...	...	@@ -2230,9 +2239,12 @@ fn makeString(self: *MachO, bytes: []const u8) !u32 {
2230	2239
2231	2240	try self.string_table.ensureCapacity(self.base.allocator, self.string_table.items.len + bytes.len + 1);
2232	2241	const offset = @intCast(u32, self.string_table.items.len);
	2242
2233	2243	log.debug("writing new string '{s}' into string table at offset 0x{x}", .{ bytes, offset });
	2244
2234	2245	self.string_table.appendSliceAssumeCapacity(bytes);
2235	2246	self.string_table.appendAssumeCapacity(0);
	2247
2236	2248	try self.string_table_directory.putNoClobber(
2237	2249	self.base.allocator,
2238	2250	try self.base.allocator.dupe(u8, bytes),

src/link/MachO/DebugSymbols.zig+28-2

...	...	@@ -534,8 +534,8 @@ pub fn flushModule(self: DebugSymbols, allocator: Allocator, options: link.Opt
534	534	mem.writeIntLittle(u64, di_buf.addManyAsArrayAssumeCapacity(8), text_section.size);
535	535
536	536	// Sentinel.
537		mem.writeIntLittle(u32, di_buf.addManyAsArrayAssumeCapacity(4), 0);
538		mem.writeIntLittle(u32, di_buf.addManyAsArrayAssumeCapacity(4), 0);
	537	mem.writeIntLittle(u64, di_buf.addManyAsArrayAssumeCapacity(8), 0);
	538	mem.writeIntLittle(u64, di_buf.addManyAsArrayAssumeCapacity(8), 0);
539	539
540	540	// Go back and populate the initial length.
541	541	const init_len = di_buf.items.len - after_init_len;
...	...	@@ -1075,6 +1075,32 @@ pub fn commitDeclDebugInfo(
1075	1075	mem.writeIntLittle(u32, ptr, @intCast(u32, text_block.size));
1076	1076	}
1077	1077
	1078	{
	1079	// Advance line and PC.
	1080	// TODO encapsulate logic in a helper function.
	1081	try dbg_line_buffer.append(DW.LNS_advance_pc);
	1082	try leb.writeULEB128(dbg_line_buffer.writer(), text_block.size);
	1083
	1084	try dbg_line_buffer.append(DW.LNS_advance_line);
	1085	const line_off: u28 = blk: {
	1086	const tree = decl.container.file_scope.tree;
	1087	const node_tags = tree.nodes.items(.tag);
	1088	const node_datas = tree.nodes.items(.data);
	1089	const token_starts = tree.tokens.items(.start);
	1090
	1091	// TODO Look into improving the performance here by adding a token-index-to-line
	1092	// lookup table. Currently this involves scanning over the source code for newlines.
	1093	const fn_decl = decl.src_node;
	1094	assert(node_tags[fn_decl] == .fn_decl);
	1095	const block = node_datas[fn_decl].rhs;
	1096	const lbrace = tree.firstToken(block);
	1097	const rbrace = tree.lastToken(block);
	1098	const line_delta = std.zig.lineDelta(tree.source, token_starts[lbrace], token_starts[rbrace]);
	1099	break :blk @intCast(u28, line_delta);
	1100	};
	1101	try leb.writeULEB128(dbg_line_buffer.writer(), line_off);
	1102	}
	1103
1078	1104	try dbg_line_buffer.appendSlice(&[_]u8{ DW.LNS_extended_op, 1, DW.LNE_end_sequence });
1079	1105
1080	1106	// Now we have the full contents and may allocate a region to store it.

test/stage2/darwin.zig+7-7

...	...	@@ -17,7 +17,7 @@ pub fn addCases(ctx: *TestContext) !void {
17	17
18	18	// Incorrect return type
19	19	case.addError(
20		\\export fn _main() noreturn {
	20	\\export fn main() noreturn {
21	21	\\}
22	22	, &[_][]const u8{":2:1: error: expected noreturn, found void"});
23	23
...	...	@@ -26,7 +26,7 @@ pub fn addCases(ctx: *TestContext) !void {
26	26	\\extern "c" fn write(usize, usize, usize) usize;
27	27	\\extern "c" fn exit(usize) noreturn;
28	28	\\
29		\\export fn _main() noreturn {
	29	\\export fn main() noreturn {
30	30	\\ print();
31	31	\\
32	32	\\ exit(0);
...	...	@@ -46,7 +46,7 @@ pub fn addCases(ctx: *TestContext) !void {
46	46	\\extern "c" fn write(usize, usize, usize) usize;
47	47	\\extern "c" fn exit(usize) noreturn;
48	48	\\
49		\\export fn _main() noreturn {
	49	\\export fn main() noreturn {
50	50	\\ print();
51	51	\\ print();
52	52	\\ print();
...	...	@@ -73,7 +73,7 @@ pub fn addCases(ctx: *TestContext) !void {
73	73	\\extern "c" fn write(usize, usize, usize) usize;
74	74	\\extern "c" fn exit(usize) noreturn;
75	75	\\
76		\\export fn _main() noreturn {
	76	\\export fn main() noreturn {
77	77	\\ print();
78	78	\\
79	79	\\ exit(0);
...	...	@@ -93,7 +93,7 @@ pub fn addCases(ctx: *TestContext) !void {
93	93	\\extern "c" fn write(usize, usize, usize) usize;
94	94	\\extern "c" fn exit(usize) noreturn;
95	95	\\
96		\\export fn _main() noreturn {
	96	\\export fn main() noreturn {
97	97	\\ print();
98	98	\\ print();
99	99	\\
...	...	@@ -119,7 +119,7 @@ pub fn addCases(ctx: *TestContext) !void {
119	119	case.addCompareOutput(
120	120	\\extern "c" fn exit(usize) noreturn;
121	121	\\
122		\\export fn _main() noreturn {
	122	\\export fn main() noreturn {
123	123	\\ exit(0);
124	124	\\}
125	125	,
...	...	@@ -130,7 +130,7 @@ pub fn addCases(ctx: *TestContext) !void {
130	130	\\extern "c" fn exit(usize) noreturn;
131	131	\\extern "c" fn write(usize, usize, usize) usize;
132	132	\\
133		\\export fn _main() noreturn {
	133	\\export fn main() noreturn {
134	134	\\ _ = write(1, @ptrToInt("Hey!\n"), 5);
135	135	\\ exit(0);
136	136	\\}