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[LLD][COFF] Don't resolve weak aliases when performing local import (#152000)

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Fixes crashes reported in #151255.

The alias may have already been stored for later resolution, which can
lead to treating a resolved alias as if it were still undefined.
Instead, use the alias target directly for the import.

Also extended the test to make reproducing the problem more likely, and
added an assert that catches the issue.
This commit is contained in:
Jacek Caban
2025-08-04 15:21:04 -07:00
committed by GitHub
parent 771d9ab701
commit 7223f67ffc
3 changed files with 18 additions and 16 deletions
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4
lld/COFF/Driver.cpp
View File

@@ -2714,8 +2714,10 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
}
ctx.symtab.initializeSameAddressThunks();
for (auto alias : aliases)
for (auto alias : aliases) {
assert(alias->kind() == Symbol::UndefinedKind);
alias->resolveWeakAlias();
}
if (config->mingw) {
// Make sure the crtend.o object is the last object file. This object

17
lld/COFF/SymbolTable.cpp
View File

@@ -478,17 +478,11 @@ void SymbolTable::resolveRemainingUndefines(std::vector<Undefined *> &aliases) {
if (name.starts_with("__imp_")) {
auto findLocalSym = [&](StringRef n) {
Symbol *sym = find(n);
if (auto undef = dyn_cast_or_null<Undefined>(sym)) {
// The unprefixed symbol might come later in symMap, so handle it now
// if needed.
if (!undef->resolveWeakAlias())
sym = nullptr;
}
return sym;
return sym ? sym->getDefined() : nullptr;
};
StringRef impName = name.substr(strlen("__imp_"));
Symbol *imp = findLocalSym(impName);
Defined *imp = findLocalSym(impName);
if (!imp && isEC()) {
// Try to use the mangled symbol on ARM64EC.
std::optional<std::string> mangledName =
@@ -502,11 +496,10 @@ void SymbolTable::resolveRemainingUndefines(std::vector<Undefined *> &aliases) {
imp = findLocalSym(*mangledName);
}
}
if (imp && isa<Defined>(imp)) {
auto *d = cast<Defined>(imp);
replaceSymbol<DefinedLocalImport>(sym, ctx, name, d);
if (imp) {
replaceSymbol<DefinedLocalImport>(sym, ctx, name, imp);
localImportChunks.push_back(cast<DefinedLocalImport>(sym)->getChunk());
localImports[sym] = d;
localImports[sym] = imp;
continue;
}
}

13
lld/test/COFF/import_weak_alias.test
View File

@@ -4,17 +4,24 @@
# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/foo.s -o %t.foo.obj
# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/qux.s -o %t.qux.obj
# RUN: lld-link %t.qux.obj %t.foo.obj -out:%t.dll -dll
# RUN: lld-link %t.foo.obj %t.qux.obj -out:%t.dll -dll
#
#--- foo.s
.text
bar:
ret
.weak foo
.set foo, bar
.weak a
.weak b
.weak c
.set a, bar
.set b, bar
.set c, bar
#--- qux.s
.text
.global _DllMainCRTStartup
_DllMainCRTStartup:
call *__imp_foo(%rip)
call *__imp_a(%rip)
call *__imp_b(%rip)
call *__imp_c(%rip)
ret