Debug Info: Fix an oversight of r186553. Ensure that the function prologue

of an artificial function gets an artificial location as well.

llvm-svn: 187074

3 files changed, 25 insertions, 10 deletions

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index ec4af58fc37..f200ec96e77 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1313,9 +1313,10 @@ CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
                                           SC_Static,
                                           false,
                                           false);
-  StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
-  // Don't emit any line table entries for the body of this function.
+  // Create a scope with an artificial location for the body of this function.
   ArtificialLocation AL(*this, Builder);
+  StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
+  AL.Emit();
 
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
@@ -1488,9 +1489,10 @@ CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
                                           SourceLocation(), II, C.VoidTy, 0,
                                           SC_Static,
                                           false, false);
-  StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
-  // Don't emit any line table entries for the body of this function.
+  // Create a scope with an artificial location for the body of this function.
   ArtificialLocation AL(*this, Builder);
+  StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
+  AL.Emit();
 
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 4de21d2b397..4e77f87cc65 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -72,13 +72,19 @@ ArtificialLocation::ArtificialLocation(CodeGenFunction &CGF, CGBuilderTy &B)
   : DI(CGF.getDebugInfo()), Builder(B) {
   if (DI) {
     SavedLoc = DI->getLocation();
+    DI->CurLoc = SourceLocation();
+    Builder.SetCurrentDebugLocation(llvm::DebugLoc());
+  }
+}
+
+void ArtificialLocation::Emit() {
+  if (DI) {
     // Sync the Builder.
     DI->EmitLocation(Builder, SavedLoc);
     DI->CurLoc = SourceLocation();
     // Construct a location that has a valid scope, but no line info.
-    llvm::DIDescriptor Scope = DI->LexicalBlockStack.empty() ?
-      llvm::DIDescriptor(DI->TheCU) :
-      llvm::DIDescriptor(DI->LexicalBlockStack.back());
+    assert(!DI->LexicalBlockStack.empty());
+    llvm::DIDescriptor Scope(DI->LexicalBlockStack.back());
     Builder.SetCurrentDebugLocation(llvm::DebugLoc::get(0, 0, Scope));
   }
 }
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 6eeb911d21e..b090c4d3bf5 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -407,9 +407,11 @@ public:
 /// an artificial debug location that has a valid scope, but no line
 /// information. This is useful when emitting compiler-generated
 /// helper functions that have no source location associated with
-/// them.
+/// them. The DWARF specification allows the compiler to use the
+/// special line number 0 to indicate code that can not be attributed
+/// to any source location.
 ///
-/// This is necessary because pasing an empty SourceLocation to
+/// This is necessary because passing an empty SourceLocation to
 /// CGDebugInfo::setLocation() will result in the last valid location
 /// being reused.
 class ArtificialLocation {
@@ -418,7 +420,12 @@ class ArtificialLocation {
   CGBuilderTy &Builder;
 public:
   ArtificialLocation(CodeGenFunction &CGF, CGBuilderTy &B);
-  /// ~BuildinLocation - Autorestore everything back to normal.
+
+  /// Set the current location to line 0, but within the current scope
+  /// (= the top of the LexicalScopeStack).
+  void Emit();
+
+  /// ~ArtificialLocation - Autorestore everything back to normal.
   ~ArtificialLocation();
 };