[codeview] emit debug info for indirect virtual base classes

Summary:
Fixes PR28281.

MSVC lists indirect virtual base classes in the field list of a class.
This change makes Clang emit the information necessary for LLVM to
emit such records.

Reviewers: rnk, ruiu, zturner

Differential Revision: https://reviews.llvm.org/D25579

llvm-svn: 285132

2 files changed, 40 insertions, 9 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 9b623d7443c..6a6b83e3314 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -13,9 +13,9 @@
 
 #include "CGDebugInfo.h"
 #include "CGBlocks.h"
-#include "CGRecordLayout.h"
 #include "CGCXXABI.h"
 #include "CGObjCRuntime.h"
+#include "CGRecordLayout.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
 #include "clang/AST/ASTContext.h"
@@ -31,6 +31,7 @@
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Lex/ModuleMap.h"
 #include "clang/Lex/PreprocessorOptions.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/Constants.h"
@@ -1380,13 +1381,33 @@ void CGDebugInfo::CollectCXXMemberFunctions(
 void CGDebugInfo::CollectCXXBases(const CXXRecordDecl *RD, llvm::DIFile *Unit,
                                   SmallVectorImpl<llvm::Metadata *> &EltTys,
                                   llvm::DIType *RecordTy) {
-  const ASTRecordLayout &RL = CGM.getContext().getASTRecordLayout(RD);
-  for (const auto &BI : RD->bases()) {
-    llvm::DINode::DIFlags BFlags = llvm::DINode::FlagZero;
-    uint64_t BaseOffset;
+  llvm::DenseSet<CanonicalDeclPtr<const CXXRecordDecl>> SeenTypes;
+  CollectCXXBasesAux(RD, Unit, EltTys, RecordTy, RD->bases(), SeenTypes,
+                     llvm::DINode::FlagZero);
+
+  // If we are generating CodeView debug info, we also need to emit records for
+  // indirect virtual base classes.
+  if (CGM.getCodeGenOpts().EmitCodeView) {
+    CollectCXXBasesAux(RD, Unit, EltTys, RecordTy, RD->vbases(), SeenTypes,
+                       llvm::DINode::FlagIndirectVirtualBase);
+  }
+}
 
+void CGDebugInfo::CollectCXXBasesAux(
+    const CXXRecordDecl *RD, llvm::DIFile *Unit,
+    SmallVectorImpl<llvm::Metadata *> &EltTys, llvm::DIType *RecordTy,
+    const CXXRecordDecl::base_class_const_range &Bases,
+    llvm::DenseSet<CanonicalDeclPtr<const CXXRecordDecl>> &SeenTypes,
+    llvm::DINode::DIFlags StartingFlags) {
+  const ASTRecordLayout &RL = CGM.getContext().getASTRecordLayout(RD);
+  for (const auto &BI : Bases) {
     const auto *Base =
         cast<CXXRecordDecl>(BI.getType()->getAs<RecordType>()->getDecl());
+    if (!SeenTypes.insert(Base).second)
+      continue;
+    auto *BaseTy = getOrCreateType(BI.getType(), Unit);
+    llvm::DINode::DIFlags BFlags = StartingFlags;
+    uint64_t BaseOffset;
 
     if (BI.isVirtual()) {
       if (CGM.getTarget().getCXXABI().isItaniumFamily()) {
@@ -1401,15 +1422,15 @@ void CGDebugInfo::CollectCXXBases(const CXXRecordDecl *RD, llvm::DIFile *Unit,
         BaseOffset =
             4 * CGM.getMicrosoftVTableContext().getVBTableIndex(RD, Base);
       }
-      BFlags = llvm::DINode::FlagVirtual;
+      BFlags |= llvm::DINode::FlagVirtual;
     } else
       BaseOffset = CGM.getContext().toBits(RL.getBaseClassOffset(Base));
     // FIXME: Inconsistent units for BaseOffset. It is in bytes when
     // BI->isVirtual() and bits when not.
 
     BFlags |= getAccessFlag(BI.getAccessSpecifier(), RD);
-    llvm::DIType *DTy = DBuilder.createInheritance(
-        RecordTy, getOrCreateType(BI.getType(), Unit), BaseOffset, BFlags);
+    llvm::DIType *DTy =
+        DBuilder.createInheritance(RecordTy, BaseTy, BaseOffset, BFlags);
     EltTys.push_back(DTy);
   }
 }
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index d2af9be9b6c..f43261a47d2 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -15,12 +15,14 @@
 #define LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
 
 #include "CGBuilder.h"
+#include "clang/AST/DeclCXX.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExternalASTSource.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Frontend/CodeGenOptions.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/DebugInfo.h"
@@ -32,7 +34,6 @@ class MDNode;
 }
 
 namespace clang {
-class CXXMethodDecl;
 class ClassTemplateSpecializationDecl;
 class GlobalDecl;
 class ModuleMap;
@@ -218,6 +219,15 @@ class CGDebugInfo {
                        SmallVectorImpl<llvm::Metadata *> &EltTys,
                        llvm::DIType *RecordTy);
 
+  /// Helper function for CollectCXXBases.
+  /// Adds debug info entries for types in Bases that are not in SeenTypes.
+  void CollectCXXBasesAux(const CXXRecordDecl *RD, llvm::DIFile *Unit,
+                          SmallVectorImpl<llvm::Metadata *> &EltTys,
+                          llvm::DIType *RecordTy,
+                          const CXXRecordDecl::base_class_const_range &Bases,
+                          llvm::DenseSet<CanonicalDeclPtr<const CXXRecordDecl>> &SeenTypes,
+                          llvm::DINode::DIFlags StartingFlags);
+
   /// A helper function to collect template parameters.
   llvm::DINodeArray CollectTemplateParams(const TemplateParameterList *TPList,
                                           ArrayRef<TemplateArgument> TAList,