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zld: fix parsing of weak symbols

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This commit is contained in:
Jakub Konka 2021-04-20 16:55:08 +02:00
parent 7bc6554a58
commit d64c76e8f1
2 changed files with 37 additions and 36 deletions
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2
src/link/MachO/Symbol.zig
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@ -52,7 +52,7 @@ pub fn isUndf(sym: macho.nlist_64) bool {
}
pub fn isWeakDef(sym: macho.nlist_64) bool {
return sym.n_desc == macho.N_WEAK_DEF;
return (sym.n_desc & macho.N_WEAK_DEF) != 0;
}
/// Symbol is local if it is defined and not an extern.

71
src/link/MachO/Zld.zig
View File

@ -1340,13 +1340,14 @@ fn resolveSymbolsInObject(self: *Zld, object_id: u16) !void {
.strong => {
if (!is_weak) {
log.debug("strong symbol '{s}' defined multiple times", .{sym_name});
return error.MultipleSymbolDefinitions;
}
continue;
},
else => {},
}
global.value.tag = .strong;
global.value.tag = if (is_weak) .weak else .strong;
global.value.file = object_id;
global.value.index = @intCast(u32, sym_id);
} else if (Symbol.isUndef(sym)) {
@ -1428,20 +1429,20 @@ fn resolveSymbols(self: *Zld) !void {
.file = 0,
});
// {
// log.warn("symtab", .{});
// for (self.symtab.items()) |sym| {
// switch (sym.value.tag) {
// .weak, .strong => {
// log.warn(" | {s} => {s}", .{ sym.key, self.objects.items[sym.value.file.?].name.? });
// },
// .import => {
// log.warn(" | {s} => libSystem.B.dylib", .{sym.key});
// },
// else => unreachable,
// }
// }
// }
{
log.debug("symtab", .{});
for (self.symtab.items()) |sym| {
switch (sym.value.tag) {
.weak, .strong => {
log.debug(" | {s} => {s}", .{ sym.key, self.objects.items[sym.value.file.?].name.? });
},
.import => {
log.debug(" | {s} => libSystem.B.dylib", .{sym.key});
},
else => unreachable,
}
}
}
}
fn resolveStubsAndGotEntries(self: *Zld) !void {
@ -1687,7 +1688,26 @@ fn relocTargetAddr(self: *Zld, object_id: u16, target: reloc.Relocation.Target)
const sym = object.symtab.items[sym_id];
const sym_name = object.getString(sym.n_strx);
if (self.symtab.get(sym_name)) |global| {
if (Symbol.isSect(sym)) {
log.debug(" | local symbol '{s}'", .{sym_name});
if (object.locals.get(sym_name)) |local| {
break :blk local.address;
}
// For temp locals, i.e., symbols prefixed with l... we relocate
// based on section addressing.
const source_sect_id = sym.n_sect - 1;
const target_mapping = self.mappings.get(.{
.object_id = object_id,
.source_sect_id = source_sect_id,
}) orelse unreachable;
const source_seg = object.load_commands.items[object.segment_cmd_index.?].Segment;
const source_sect = source_seg.sections.items[source_sect_id];
const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment;
const target_sect = target_seg.sections.items[target_mapping.target_sect_id];
const target_addr = target_sect.addr + target_mapping.offset;
break :blk sym.n_value - source_sect.addr + target_addr;
} else if (self.symtab.get(sym_name)) |global| {
switch (global.tag) {
.weak, .strong => {
log.debug(" | global symbol '{s}'", .{sym_name});
@ -1711,25 +1731,6 @@ fn relocTargetAddr(self: *Zld, object_id: u16, target: reloc.Relocation.Target)
},
else => unreachable,
}
} else if (Symbol.isSect(sym)) {
log.debug(" | local symbol '{s}'", .{sym_name});
if (object.locals.get(sym_name)) |local| {
break :blk local.address;
}
// For temp locals, i.e., symbols prefixed with l... we relocate
// based on section addressing.
const source_sect_id = sym.n_sect - 1;
const target_mapping = self.mappings.get(.{
.object_id = object_id,
.source_sect_id = source_sect_id,
}) orelse unreachable;
const source_seg = object.load_commands.items[object.segment_cmd_index.?].Segment;
const source_sect = source_seg.sections.items[source_sect_id];
const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment;
const target_sect = target_seg.sections.items[target_mapping.target_sect_id];
const target_addr = target_sect.addr + target_mapping.offset;
break :blk sym.n_value - source_sect.addr + target_addr;
} else {
log.err("failed to resolve symbol '{s}' as a relocation target", .{sym_name});
return error.FailedToResolveRelocationTarget;