Avoid producing mismatched comdats.
The problem was that given
template<typename T>
struct foo {
~foo() {}
};
template class foo<int>;
We would produce a alias, creating a comdat with D0 and D1, since the symbols
have to be weak. Another TU is not required to have a explicit template
instantiation definition or an explict template instantiation declaration and
for
template<typename T>
struct foo {
~foo() {}
};
foo<int> a;
we would produce a comdat with only one symbol in it.
llvm-svn: 194520
diff --git a/clang/lib/CodeGen/CGCXX.cpp b/clang/lib/CodeGen/CGCXX.cpp
index 0f55616..b16c59d 100644
--- a/clang/lib/CodeGen/CGCXX.cpp
+++ b/clang/lib/CodeGen/CGCXX.cpp
@@ -146,14 +146,15 @@
/// how aliases work.
if (Ref->isDeclaration())
return true;
-
- // Don't create an alias to a linker weak symbol unless we know we can do
- // that in every TU. This avoids producing different COMDATs in different
- // TUs.
- if (llvm::GlobalValue::isWeakForLinker(TargetLinkage))
- return true;
}
+ // Don't create an alias to a linker weak symbol. This avoids producing
+ // different COMDATs in different TUs. Another option would be to
+ // output the alias both for weak_odr and linkonce_odr, but that
+ // requires explicit comdat support in the IL.
+ if (llvm::GlobalValue::isWeakForLinker(TargetLinkage))
+ return true;
+
// Create the alias with no name.
llvm::GlobalAlias *Alias =
new llvm::GlobalAlias(AliasType, Linkage, "", Aliasee, &getModule());