[codeview] support emitting indirect virtual base class information

Summary:
Fixes PR28281.

MSVC lists indirect virtual base classes in the field list of a class,
using LF_IVBCLASS records. This change makes LLVM emit such records
when processing DW_TAG_inheritance tags with the DIFlagVirtual and
(newly introduced) DIFlagIndirect tags.

Reviewers: rnk, ruiu, zturner

Differential Revision: https://reviews.llvm.org/D25578

llvm-svn: 285130

3 files changed, 13 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index a305e3d3ab9..a1fd0dc8869 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1786,8 +1786,11 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
       unsigned VBPtrOffset = 0;
       // FIXME: Despite the accessor name, the offset is really in bytes.
       unsigned VBTableIndex = I->getOffsetInBits() / 4;
+      auto RecordKind = (I->getFlags() & DINode::FlagIndirectVirtualBase) == DINode::FlagIndirectVirtualBase
+                            ? TypeRecordKind::IndirectVirtualBaseClass
+                            : TypeRecordKind::VirtualBaseClass;
       Fields.writeMemberType(VirtualBaseClassRecord(
-          translateAccessFlags(Ty->getTag(), I->getFlags()),
+          RecordKind, translateAccessFlags(Ty->getTag(), I->getFlags()),
           getTypeIndex(I->getBaseType()), getVBPTypeIndex(), VBPtrOffset,
           VBTableIndex));
     } else {
diff --git a/llvm/lib/DebugInfo/CodeView/TypeRecord.cpp b/llvm/lib/DebugInfo/CodeView/TypeRecord.cpp
index a7a1bb9228c..7a2dc8fa803 100644
--- a/llvm/lib/DebugInfo/CodeView/TypeRecord.cpp
+++ b/llvm/lib/DebugInfo/CodeView/TypeRecord.cpp
@@ -382,8 +382,8 @@ VirtualBaseClassRecord::deserialize(TypeRecordKind Kind,
   uint64_t Offset;
   uint64_t Index;
   CV_DESERIALIZE(Reader, L, CV_NUMERIC_FIELD(Offset), CV_NUMERIC_FIELD(Index));
-  return VirtualBaseClassRecord(L->Attrs.getAccess(), L->BaseType, L->VBPtrType,
-                                Offset, Index);
+  return VirtualBaseClassRecord(Kind, L->Attrs.getAccess(), L->BaseType,
+                                L->VBPtrType, Offset, Index);
 }
 
 Expected<ListContinuationRecord>
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 19f02cd38d6..17c828a5d26 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -84,8 +84,9 @@ StringRef DINode::getFlagString(DIFlags Flag) {
 
 DINode::DIFlags DINode::splitFlags(DIFlags Flags,
                                    SmallVectorImpl<DIFlags> &SplitFlags) {
-  // Accessibility and member pointer flags need to be specially handled, since
-  // they're packed together.
+  // Flags that are packed together need to be specially handled, so
+  // that, for example, we emit "DIFlagPublic" and not
+  // "DIFlagPrivate | DIFlagProtected".
   if (DIFlags A = Flags & FlagAccessibility) {
     if (A == FlagPrivate)
       SplitFlags.push_back(FlagPrivate);
@@ -104,6 +105,10 @@ DINode::DIFlags DINode::splitFlags(DIFlags Flags,
       SplitFlags.push_back(FlagVirtualInheritance);
     Flags &= ~R;
   }
+  if ((Flags & FlagIndirectVirtualBase) == FlagIndirectVirtualBase) {
+    Flags &= ~FlagIndirectVirtualBase;
+    SplitFlags.push_back(FlagIndirectVirtualBase);
+  }
 
 #define HANDLE_DI_FLAG(ID, NAME)                                               \
   if (DIFlags Bit = Flags & Flag##NAME) {                                      \