[clang] AST: fix dependency calculation for TypedefTypes (#143291)

The dependency from the type sugar of the underlying type of a Typedef
were not being considered for the dependency of the TypedefType itself.

A TypedefType should be instantiation dependent if it involves
non-instantiated template parameters, even if they don't contribute to
the canonical type.

Besides, a TypedefType should be instantiation dependent if it is
declared in a dependent context, but fixing that would have performance
consequences, as otherwise non-dependent typedef declarations would need
to be transformed during instantiation as well.

This removes the workaround added in
https://github.com/llvm/llvm-project/pull/90032

Fixes https://github.com/llvm/llvm-project/issues/89774

1 files changed, 1 insertions, 22 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 001b208..ee5e3d6 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1564,28 +1564,7 @@ llvm::DIType *CGDebugInfo::CreateType(const TemplateSpecializationType *Ty,
 
   SourceLocation Loc = AliasDecl->getLocation();
 
-  if (CGM.getCodeGenOpts().DebugTemplateAlias &&
-      // FIXME: This is a workaround for the issue
-      //        https://github.com/llvm/llvm-project/issues/89774
-      // The TemplateSpecializationType doesn't contain any instantiation
-      // information; dependent template arguments can't be resolved. For now,
-      // fall back to DW_TAG_typedefs for template aliases that are
-      // instantiation dependent, e.g.:
-      // ```
-      // template <int>
-      // using A = int;
-      //
-      // template<int I>
-      // struct S {
-      //   using AA = A<I>; // Instantiation dependent.
-      //   AA aa;
-      // };
-      //
-      // S<0> s;
-      // ```
-      // S::AA's underlying type A<I> is dependent on I so will be emitted as a
-      // DW_TAG_typedef.
-      !Ty->isInstantiationDependentType()) {
+  if (CGM.getCodeGenOpts().DebugTemplateAlias) {
     auto ArgVector = ::GetTemplateArgs(TD, Ty);
     TemplateArgs Args = {TD->getTemplateParameters(), ArgVector};