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macho: fix generating valid debug info in -r mode
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@kubkon
kubkon committed Jan 5, 2024
1 parent 5012a81 commit b79c6de
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Showing 2 changed files with 55 additions and 36 deletions.
18 changes: 9 additions & 9 deletions src/MachO.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -594,14 +594,12 @@ fn validateCpuArch(self: *MachO, index: File.Index) void {
macho.CPU_TYPE_X86_64 => .x86_64,
else => unreachable,
};
if (self.options.cpu_arch) |self_cpu_arch| {
if (self_cpu_arch != cpu_arch) {
return self.base.fatal("{}: invalid architecture '{s}', expected '{s}'", .{
file.fmtPath(),
@tagName(cpu_arch),
@tagName(self_cpu_arch),
});
}
if (self.options.cpu_arch.? != cpu_arch) {
return self.base.fatal("{}: invalid architecture '{s}', expected '{s}'", .{
file.fmtPath(),
@tagName(cpu_arch),
@tagName(self.options.cpu_arch.?),
});
}
}

Expand Down Expand Up @@ -752,11 +750,13 @@ fn parseArchive(self: *MachO, arena: Allocator, obj: LinkObject) !bool {
object.parse(self) catch |err| switch (err) {
error.ParseFailed => {
has_parse_error = true;
continue;
// TODO see below
// continue;
},
else => |e| return e,
};
try self.objects.append(gpa, index);
// TODO this should come before reporting any parse errors
self.validateCpuArch(index);
self.validatePlatform(index);

Expand Down
73 changes: 46 additions & 27 deletions src/MachO/Object.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,7 @@ pub fn parse(self: *Object, macho_file: *MachO) !void {

try self.sortAtoms(macho_file);
try self.initSymbols(macho_file);
try self.initSymbolStabs(macho_file);
try self.initSymbolStabs(nlists.items, macho_file);
try self.initRelocs(macho_file);

if (self.eh_frame_sect_index) |index| {
Expand Down Expand Up @@ -456,10 +456,23 @@ fn initSymbols(self: *Object, macho_file: *MachO) !void {
}
}

fn initSymbolStabs(self: *Object, macho_file: *MachO) !void {
fn initSymbolStabs(self: *Object, nlists: anytype, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();

const SymbolLookup = struct {
ctx: *const Object,
entries: @TypeOf(nlists),

fn find(fs: @This(), addr: u64) ?Symbol.Index {
// TODO binary search since we have the list sorted
for (fs.entries) |nlist| {
if (nlist.nlist.n_value == addr) return fs.ctx.symbols.items[nlist.idx];
}
return null;
}
};

const start: u32 = for (self.symtab.items(.nlist), 0..) |nlist, i| {
if (nlist.stab()) break @intCast(i);
} else @intCast(self.symtab.items(.nlist).len);
Expand All @@ -470,11 +483,12 @@ fn initSymbolStabs(self: *Object, macho_file: *MachO) !void {
if (start == end) return;

const gpa = macho_file.base.allocator;
const nlists = self.symtab.items(.nlist);
const syms = self.symtab.items(.nlist);
const sym_lookup = SymbolLookup{ .ctx = self, .entries = nlists };

var i: u32 = start;
while (i < end) : (i += 1) {
const open = nlists[i];
const open = syms[i];
if (open.n_type != macho.N_SO) {
macho_file.base.fatal("{}: unexpected symbol stab type 0x{x} as the first entry", .{
self.fmtPath(),
Expand All @@ -483,19 +497,19 @@ fn initSymbolStabs(self: *Object, macho_file: *MachO) !void {
return error.ParseFailed;
}

while (i < end and nlists[i].n_type == macho.N_SO and nlists[i].n_sect != 0) : (i += 1) {}
while (i < end and syms[i].n_type == macho.N_SO and syms[i].n_sect != 0) : (i += 1) {}

var sf: StabFile = .{ .comp_dir = i };
// TODO validate
i += 3;

while (i < end and nlists[i].n_type != macho.N_SO) : (i += 1) {
const nlist = nlists[i];
while (i < end and syms[i].n_type != macho.N_SO) : (i += 1) {
const nlist = syms[i];
var stab: StabFile.Stab = .{};
switch (nlist.n_type) {
macho.N_BNSYM => {
stab.tag = .func;
stab.symbol = self.findSymbolByAddress(nlist.n_value);
stab.symbol = sym_lookup.find(nlist.n_value);
// TODO validate
i += 3;
},
Expand All @@ -505,7 +519,7 @@ fn initSymbolStabs(self: *Object, macho_file: *MachO) !void {
},
macho.N_STSYM => {
stab.tag = .static;
stab.symbol = self.findSymbolByAddress(nlist.n_value);
stab.symbol = sym_lookup.find(nlist.n_value);
},
else => {
macho_file.base.fatal("{}: unhandled symbol stab type 0x{x}", .{
Expand Down Expand Up @@ -665,30 +679,27 @@ fn initEhFrameRecords(self: *Object, sect_id: u8, macho_file: *MachO) !void {
}
}

fn findSymbolByAddress(self: Object, addr: u64) ?Symbol.Index {
for (self.symbols.items, 0..) |sym_index, i| {
const nlist = self.symtab.items(.nlist)[i];
if (nlist.stab() or !nlist.sect()) continue;
if (nlist.n_value == addr) return sym_index;
}
return null;
}

fn findSymbol(self: Object, addr: u64) ?Symbol.Index {
for (self.symbols.items, 0..) |sym_index, i| {
const nlist = self.symtab.items(.nlist)[i];
if (nlist.ext() and nlist.n_value == addr) return sym_index;
}
return null;
}

fn initUnwindRecords(self: *Object, sect_id: u8, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();

const SymbolLookup = struct {
ctx: *const Object,

fn find(fs: @This(), addr: u64) ?Symbol.Index {
for (fs.ctx.symbols.items, 0..) |sym_index, i| {
const nlist = fs.ctx.symtab.items(.nlist)[i];
if (nlist.ext() and nlist.n_value == addr) return sym_index;
}
return null;
}
};

const gpa = macho_file.base.allocator;
const data = self.getSectionData(sect_id);
const nrecs = @divExact(data.len, @sizeOf(macho.compact_unwind_entry));
const recs = @as([*]align(1) const macho.compact_unwind_entry, @ptrCast(data.ptr))[0..nrecs];
const sym_lookup = SymbolLookup{ .ctx = self };

try self.unwind_records.resize(gpa, nrecs);

Expand Down Expand Up @@ -739,7 +750,7 @@ fn initUnwindRecords(self: *Object, sect_id: u8, macho_file: *MachO) !void {
.@"extern" => {
out.personality = rel.target;
},
.local => if (self.findSymbol(rec.personalityFunction)) |sym_index| {
.local => if (sym_lookup.find(rec.personalityFunction)) |sym_index| {
out.personality = sym_index;
} else {
macho_file.base.fatal("{}: {s},{s}: 0x{x}: bad relocation", .{
Expand Down Expand Up @@ -1155,6 +1166,10 @@ pub fn calcStabsSize(self: *Object, macho_file: *MachO) void {
const file = sym.getFile(macho_file) orelse continue;
if (file.getIndex() != self.index) continue;
if (!sym.flags.output_symtab) continue;
if (macho_file.options.relocatable) {
const name = sym.getName(macho_file);
if (name.len > 0 and (name[0] == 'L' or name[0] == 'l')) continue;
}
const sect = macho_file.sections.items(.header)[sym.out_n_sect];
if (sect.isCode()) {
self.output_symtab_ctx.nstabs += 4; // N_BNSYM, N_FUN, N_FUN, N_ENSYM
Expand Down Expand Up @@ -1309,6 +1324,10 @@ pub fn writeStabs(self: *const Object, macho_file: *MachO) void {
const file = sym.getFile(macho_file) orelse continue;
if (file.getIndex() != self.index) continue;
if (!sym.flags.output_symtab) continue;
if (macho_file.options.relocatable) {
const name = sym.getName(macho_file);
if (name.len > 0 and (name[0] == 'L' or name[0] == 'l')) continue;
}
const sect = macho_file.sections.items(.header)[sym.out_n_sect];
const sym_n_strx = n_strx: {
const symtab_index = sym.getOutputSymtabIndex(macho_file).?;
Expand Down

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