Revert "PR14569: Omit debug info for thunks"

This reverts commit r189320.

Alexey Samsonov and Dmitry Vyukov presented some arguments for keeping
these around - though it still seems like those tasks could be solved by
a tool just using the symbol table. In a very small number of cases,
thunks may be inlined & debug info might be able to save profilers &
similar tools from misclassifying those cases as part of the caller.

The extra changes here plumb through the VarDecl for various cases to
CodeGenFunction - this provides better fidelity through a few APIs but
generally just causes the CGF::StartFunction to fallback to using the
name of the IR function as the name in the debug info.

The changes to debug-info-global-ctor-dtor.cpp seem like goodness. The
two names that go missing (in favor of only emitting those names as
linkage names) are names that can be demangled - emitting them only as
the linkage name should encourage tools to do just that.

Again, thanks to Dinesh Dwivedi for investigation/work on this issue.

llvm-svn: 189421

1 files changed, 0 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 6eb3e89d273..26ebf913a9b 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -292,7 +292,6 @@ void CodeGenFunction::GenerateVarArgsThunk(
 void CodeGenFunction::GenerateThunk(llvm::Function *Fn,
                                     const CGFunctionInfo &FnInfo,
                                     GlobalDecl GD, const ThunkInfo &Thunk) {
-  DebugInfo = NULL; // debug info for thunks is not required or desired
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
   const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
   QualType ThisType = MD->getThisType(getContext());