[CodeView] Initial support for emitting S_THUNK32 symbols for compiler...

When emitting CodeView debug information, compiler-generated thunk routines
should be emitted using S_THUNK32 symbols instead of S_GPROC32_ID symbols so
Visual Studio can properly step into the user code.  This initial support only
handles standard thunk ordinals.

Differential Revision: https://reviews.llvm.org/D43838

llvm-svn: 330132

3 files changed, 10 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 47b8e436752..bdd326d70e4 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3217,7 +3217,8 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateFunctionType(const Decl *D,
 
 void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
                                     SourceLocation ScopeLoc, QualType FnType,
-                                    llvm::Function *Fn, CGBuilderTy &Builder) {
+                                    llvm::Function *Fn, bool CurFuncIsThunk,
+                                    CGBuilderTy &Builder) {
 
   StringRef Name;
   StringRef LinkageName;
@@ -3263,6 +3264,10 @@ void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
     // Artificial functions should not silently reuse CurLoc.
     CurLoc = SourceLocation();
   }
+
+  if (CurFuncIsThunk)
+    Flags |= llvm::DINode::FlagThunk;
+
   unsigned LineNo = getLineNumber(Loc);
   unsigned ScopeLine = getLineNumber(ScopeLoc);
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 459d7e00b6f..5cd77177972 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -366,7 +366,8 @@ public:
   /// \param ScopeLoc  The location of the function body.
   void EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
                          SourceLocation ScopeLoc, QualType FnType,
-                         llvm::Function *Fn, CGBuilderTy &Builder);
+                         llvm::Function *Fn, bool CurFnIsThunk,
+                         CGBuilderTy &Builder);
 
   /// Start a new scope for an inlined function.
   void EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD);
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 357f0d74376..92564043e07 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1018,7 +1018,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
       ArgTypes.push_back(VD->getType());
     QualType FnType = getContext().getFunctionType(
         RetTy, ArgTypes, FunctionProtoType::ExtProtoInfo(CC));
-    DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, Builder);
+    DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, CurFuncIsThunk,
+                          Builder);
   }
 
   if (ShouldInstrumentFunction()) {