PR32042: Create inlined debug info for EmitInlinedInheritingCXXConstructorCall.

When clang emits an inheriting C++ constructor it may inline code
during the CodeGen phase. This patch ensures that any debug info in
this inlined code gets a proper inlined location. Otherwise we can end
up with invalid debug info metadata, since all inlined local variables
and function arguments would be reparented into the call site.

Analogous to ApplyInlineLocation this patch introduces a
ApplyInlineDebugLocation scoped helper to facilitate entering an
inlined scope and cleaning up afterwards.

This fixes one of the issues discovered in PR32042.

rdar://problem/30679307

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@296388 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 41 insertions, 3 deletions

diff --git a/lib/CodeGen/CGDebugInfo.h b/lib/CodeGen/CGDebugInfo.h
index 050665e92e..c9a44cf70d 100644
--- a/lib/CodeGen/CGDebugInfo.h
+++ b/lib/CodeGen/CGDebugInfo.h
@@ -61,6 +61,7 @@ class CGDebugInfo {
   ModuleMap *ClangModuleMap = nullptr;
   ExternalASTSource::ASTSourceDescriptor PCHDescriptor;
   SourceLocation CurLoc;
+  llvm::MDNode *CurInlinedAt = nullptr;
   llvm::DIType *VTablePtrType = nullptr;
   llvm::DIType *ClassTy = nullptr;
   llvm::DICompositeType *ObjTy = nullptr;
@@ -320,6 +321,17 @@ public:
   /// ignored.
   void setLocation(SourceLocation Loc);
 
+  /// Return the current source location. This does not necessarily correspond
+  /// to the IRBuilder's current DebugLoc.
+  SourceLocation getLocation() const { return CurLoc; }
+
+  /// Update the current inline scope. All subsequent calls to \p EmitLocation
+  /// will create a location with this inlinedAt field.
+  void setInlinedAt(llvm::MDNode *InlinedAt) { CurInlinedAt = InlinedAt; }
+
+  /// \return the current inline scope.
+  llvm::MDNode *getInlinedAt() const { return CurInlinedAt; }
+
   // Converts a SourceLocation to a DebugLoc
   llvm::DebugLoc SourceLocToDebugLoc(SourceLocation Loc);
 
@@ -336,6 +348,11 @@ public:
                          SourceLocation ScopeLoc, QualType FnType,
                          llvm::Function *Fn, CGBuilderTy &Builder);
 
+  /// Start a new scope for an inlined function.
+  void EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD);
+  /// End an inlined function scope.
+  void EmitInlineFunctionEnd(CGBuilderTy &Builder);
+
   /// Emit debug info for a function declaration.
   void EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc, QualType FnType);
 
@@ -502,11 +519,18 @@ private:
   llvm::DIDerivedType *
   getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D);
 
+  /// Helper that either creates a forward declaration or a stub.
+  llvm::DISubprogram *getFunctionFwdDeclOrStub(GlobalDecl GD, bool Stub);
+
   /// Create a subprogram describing the forward declaration
-  /// represented in the given FunctionDecl.
-  llvm::DISubprogram *getFunctionForwardDeclaration(const FunctionDecl *FD);
+  /// represented in the given FunctionDecl wrapped in a GlobalDecl.
+  llvm::DISubprogram *getFunctionForwardDeclaration(GlobalDecl GD);
+
+  /// Create a DISubprogram describing the function
+  /// represented in the given FunctionDecl wrapped in a GlobalDecl.
+  llvm::DISubprogram *getFunctionStub(GlobalDecl GD);
 
-  /// Create a global variable describing the forward decalration
+  /// Create a global variable describing the forward declaration
   /// represented in the given VarDecl.
   llvm::DIGlobalVariable *
   getGlobalVariableForwardDeclaration(const VarDecl *VD);
@@ -633,6 +657,20 @@ public:
 
 };
 
+/// A scoped helper to set the current debug location to an inlined location.
+class ApplyInlineDebugLocation {
+  SourceLocation SavedLocation;
+  CodeGenFunction *CGF;
+
+public:
+  /// Set up the CodeGenFunction's DebugInfo to produce inline locations for the
+  /// function \p InlinedFn. The current debug location becomes the inlined call
+  /// site of the inlined function.
+  ApplyInlineDebugLocation(CodeGenFunction &CGF, GlobalDecl InlinedFn);
+  /// Restore everything back to the orginial state.
+  ~ApplyInlineDebugLocation();
+};
+
 } // namespace CodeGen
 } // namespace clang