[mingw] Use unmangled name after the $ in the section name

GCC does it this way, and we have to be consistent. This includes
stdcall and fastcall functions with suffixes. I confirmed that a
fastcall function named "foo" ends up in ".text$foo", not
".text$@foo@8".

Based on a patch by Andrew Yohn!

Fixes PR39218.

Differential Revision: https://reviews.llvm.org/D54762

llvm-svn: 347431

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 341ab92..5f4421f 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1317,10 +1317,11 @@ MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
       MCSymbol *Sym = TM.getSymbol(ComdatGV);
       StringRef COMDATSymName = Sym->getName();
 
-      // Append "$symbol" to the section name when targetting mingw. The ld.bfd
+      // Append "$symbol" to the section name *before* IR-level mangling is
+      // applied when targetting mingw. This is what GCC does, and the ld.bfd
       // COFF linker will not properly handle comdats otherwise.
       if (getTargetTriple().isWindowsGNUEnvironment())
-        raw_svector_ostream(Name) << '$' << COMDATSymName;
+        raw_svector_ostream(Name) << '$' << ComdatGV->getName();
 
       return getContext().getCOFFSection(Name, Characteristics, Kind,
                                          COMDATSymName, Selection, UniqueID);