[Reapply r128776, modified so that it does not break debug info.]

Change the return type of CodeGenVTables::getVirtualBaseOffsetOffset() to
CharUnits. No change in functionality intended.

llvm-svn: 129072

clang/lib/CodeGen/CGClass.cpp

@@ -1317,11 +1317,12 @@ CodeGenFunction::GetVirtualBaseClassOffset(llvm::Value *This,
                                            const CXXRecordDecl *ClassDecl,
                                            const CXXRecordDecl *BaseClassDecl) {
   llvm::Value *VTablePtr = GetVTablePtr(This, Int8PtrTy);
-  int64_t VBaseOffsetOffset = 
+  CharUnits VBaseOffsetOffset = 
     CGM.getVTables().getVirtualBaseOffsetOffset(ClassDecl, BaseClassDecl);
   
   llvm::Value *VBaseOffsetPtr = 
-    Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset, "vbase.offset.ptr");
+    Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetOffset.getQuantity(), 
+                               "vbase.offset.ptr");
   const llvm::Type *PtrDiffTy = 
     ConvertType(getContext().getPointerDiffType());
   

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -814,10 +814,13 @@ CollectCXXBases(const CXXRecordDecl *RD, llvm::DIFile Unit,
     if (BI->isVirtual()) {
       // virtual base offset offset is -ve. The code generator emits dwarf
       // expression where it expects +ve number.
-      BaseOffset = 0 - CGM.getVTables().getVirtualBaseOffsetOffset(RD, Base);
+      BaseOffset = 
+        0 - CGM.getVTables().getVirtualBaseOffsetOffset(RD, Base).getQuantity();
       BFlags = llvm::DIDescriptor::FlagVirtual;
     } else
       BaseOffset = RL.getBaseClassOffsetInBits(Base);
+    // FIXME: Inconsistent units for BaseOffset. It is in bytes when
+    // BI->isVirtual() and bits when not.
     
     AccessSpecifier Access = BI->getAccessSpecifier();
     if (Access == clang::AS_private)

clang/lib/CodeGen/CGRTTI.cpp

@@ -878,7 +878,8 @@ void RTTIBuilder::BuildVMIClassTypeInfo(const CXXRecordDecl *RD) {
     // subobject. For a virtual base, this is the offset in the virtual table of
     // the virtual base offset for the virtual base referenced (negative).
     if (Base->isVirtual())
-      OffsetFlags = CGM.getVTables().getVirtualBaseOffsetOffset(RD, BaseDecl);
+      OffsetFlags = 
+        CGM.getVTables().getVirtualBaseOffsetOffset(RD, BaseDecl).getQuantity();
     else {
       const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
       OffsetFlags = Layout.getBaseClassOffsetInBits(BaseDecl) / 8;

clang/lib/CodeGen/CGVTables.cpp

@@ -1339,7 +1339,7 @@ ReturnAdjustment VTableBuilder::ComputeReturnAdjustment(BaseOffset Offset) {
       } else {
         Adjustment.VBaseOffsetOffset = 
           VTables.getVirtualBaseOffsetOffset(Offset.DerivedClass,
-                                             Offset.VirtualBase);
+                                             Offset.VirtualBase).getQuantity();
       }
     }
 
@@ -2431,14 +2431,15 @@ uint64_t CodeGenVTables::getMethodVTableIndex(GlobalDecl GD) {
   return I->second;
 }
 
-int64_t CodeGenVTables::getVirtualBaseOffsetOffset(const CXXRecordDecl *RD, 
-                                                   const CXXRecordDecl *VBase) {
+CharUnits 
+CodeGenVTables::getVirtualBaseOffsetOffset(const CXXRecordDecl *RD, 
+                                           const CXXRecordDecl *VBase) {
   ClassPairTy ClassPair(RD, VBase);
   
   VirtualBaseClassOffsetOffsetsMapTy::iterator I = 
     VirtualBaseClassOffsetOffsets.find(ClassPair);
   if (I != VirtualBaseClassOffsetOffsets.end())
-    return I->second.getQuantity();
+    return I->second;
   
   VCallAndVBaseOffsetBuilder Builder(RD, RD, /*FinalOverriders=*/0,
                                      BaseSubobject(RD, CharUnits::Zero()),
@@ -2458,7 +2459,7 @@ int64_t CodeGenVTables::getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
   I = VirtualBaseClassOffsetOffsets.find(ClassPair);
   assert(I != VirtualBaseClassOffsetOffsets.end() && "Did not find index!");
   
-  return I->second.getQuantity();
+  return I->second;
 }
 
 uint64_t

clang/lib/CodeGen/CGVTables.h

@@ -235,13 +235,13 @@ public:
   /// stored.
   uint64_t getMethodVTableIndex(GlobalDecl GD);
 
-  /// getVirtualBaseOffsetOffset - Return the offset in bytes (relative to the
+  /// getVirtualBaseOffsetOffset - Return the offset in chars (relative to the
   /// vtable address point) where the offset of the virtual base that contains 
   /// the given base is stored, otherwise, if no virtual base contains the given
   /// class, return 0.  Base must be a virtual base class or an unambigious
   /// base.
-  int64_t getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
-                                     const CXXRecordDecl *VBase);
+  CharUnits getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
+                                       const CXXRecordDecl *VBase);
 
   /// getAddressPoint - Get the address point of the given subobject in the
   /// class decl.