[CGDebugInfo] Finalize SubPrograms when we're done with them

`GenerateVarArgsThunk` in `CGVTables` clones a function before the frontend
is done emitting the compilation unit. Because of the way that DIBuilder
works, this means that the attached subprogram had incomplete (temporary)
metadata. Cloning such metadata is semantically disallowed, but happened
to work anyway due to bugs in the cloning logic. rL304226 attempted to fix
up that logic, but in the process exposed the incorrect API use here and
had to be reverted. To be able to fix this, I added a new method to
DIBuilder in rL304467, to allow finalizing a subprogram independently
of the entire compilation unit. Use that here, in preparation of re-applying
rL304226.

Reviewers: aprantl, dblaikie
Differential Revision: https://reviews.llvm.org/D33705

llvm-svn: 304470

3 files changed, 7 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 0a1dc09211c..3ed388974c4 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3263,7 +3263,7 @@ void CGDebugInfo::EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD) {
 
 void CGDebugInfo::EmitInlineFunctionEnd(CGBuilderTy &Builder) {
   assert(CurInlinedAt && "unbalanced inline scope stack");
-  EmitFunctionEnd(Builder);
+  EmitFunctionEnd(Builder, nullptr);
   setInlinedAt(llvm::DebugLoc(CurInlinedAt).getInlinedAt());
 }
 
@@ -3332,7 +3332,7 @@ void CGDebugInfo::EmitLexicalBlockEnd(CGBuilderTy &Builder,
   LexicalBlockStack.pop_back();
 }
 
-void CGDebugInfo::EmitFunctionEnd(CGBuilderTy &Builder) {
+void CGDebugInfo::EmitFunctionEnd(CGBuilderTy &Builder, llvm::Function *Fn) {
   assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
   unsigned RCount = FnBeginRegionCount.back();
   assert(RCount <= LexicalBlockStack.size() && "Region stack mismatch");
@@ -3344,6 +3344,9 @@ void CGDebugInfo::EmitFunctionEnd(CGBuilderTy &Builder) {
     LexicalBlockStack.pop_back();
   }
   FnBeginRegionCount.pop_back();
+
+  if (Fn && Fn->getSubprogram())
+    DBuilder.finalizeSubprogram(Fn->getSubprogram());
 }
 
 llvm::DIType *CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 7de48f27899..39249c7cf4d 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -367,7 +367,7 @@ public:
   void EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc, QualType FnType);
 
   /// Constructs the debug code for exiting a function.
-  void EmitFunctionEnd(CGBuilderTy &Builder);
+  void EmitFunctionEnd(CGBuilderTy &Builder, llvm::Function *Fn);
 
   /// Emit metadata to indicate the beginning of a new lexical block
   /// and push the block onto the stack.
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 85da3ae47db..b6d7f025501 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -348,7 +348,7 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
 
   // Emit debug descriptor for function end.
   if (CGDebugInfo *DI = getDebugInfo())
-    DI->EmitFunctionEnd(Builder);
+    DI->EmitFunctionEnd(Builder, CurFn);
 
   // Reset the debug location to that of the simple 'return' expression, if any
   // rather than that of the end of the function's scope '}'.