Author: majnemer Date: Tue Jun 23 15:34:18 2015 New Revision: 240453 URL: http://llvm.org/viewvc/llvm-project?rev=240453&view=rev Log: [MS ABI] Account for the virtual inheritance quirk when mangling
Virtual inheritance member pointers are always relative to the vbindex, even when the member pointer doesn't point into a virtual base. This is corrected by adjusting the non-virtual offset backwards from the vbptr back to the top of the most derived class. While we performed this adjustment when manifesting member pointers as constants or when performing conversions, we didn't perform the adjustment when mangling them. Modified: cfe/trunk/include/clang/AST/ASTContext.h cfe/trunk/lib/AST/ASTContext.cpp cfe/trunk/lib/AST/MicrosoftMangle.cpp cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp cfe/trunk/test/CodeGenCXX/mangle-ms-templates-memptrs.cpp Modified: cfe/trunk/include/clang/AST/ASTContext.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTContext.h?rev=240453&r1=240452&r2=240453&view=diff ============================================================================== --- cfe/trunk/include/clang/AST/ASTContext.h (original) +++ cfe/trunk/include/clang/AST/ASTContext.h Tue Jun 23 15:34:18 2015 @@ -1780,6 +1780,17 @@ public: /// \param method should be the declaration from the class definition void setNonKeyFunction(const CXXMethodDecl *method); + /// Loading virtual member pointers using the virtual inheritance model + /// always results in an adjustment using the vbtable even if the index is + /// zero. + /// + /// This is usually OK because the first slot in the vbtable points + /// backwards to the top of the MDC. However, the MDC might be reusing a + /// vbptr from an nv-base. In this case, the first slot in the vbtable + /// points to the start of the nv-base which introduced the vbptr and *not* + /// the MDC. Modify the NonVirtualBaseAdjustment to account for this. + CharUnits getOffsetOfBaseWithVBPtr(const CXXRecordDecl *RD) const; + /// Get the offset of a FieldDecl or IndirectFieldDecl, in bits. uint64_t getFieldOffset(const ValueDecl *FD) const; Modified: cfe/trunk/lib/AST/ASTContext.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=240453&r1=240452&r2=240453&view=diff ============================================================================== --- cfe/trunk/lib/AST/ASTContext.cpp (original) +++ cfe/trunk/lib/AST/ASTContext.cpp Tue Jun 23 15:34:18 2015 @@ -1866,6 +1866,16 @@ CharUnits ASTContext::getAlignOfGlobalVa return toCharUnitsFromBits(getAlignOfGlobalVar(T)); } +CharUnits ASTContext::getOffsetOfBaseWithVBPtr(const CXXRecordDecl *RD) const { + CharUnits Offset = CharUnits::Zero(); + const ASTRecordLayout *Layout = &getASTRecordLayout(RD); + while (const CXXRecordDecl *Base = Layout->getBaseSharingVBPtr()) { + Offset += Layout->getBaseClassOffset(Base); + Layout = &getASTRecordLayout(Base); + } + return Offset; +} + /// DeepCollectObjCIvars - /// This routine first collects all declared, but not synthesized, ivars in /// super class and then collects all ivars, including those synthesized for Modified: cfe/trunk/lib/AST/MicrosoftMangle.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/MicrosoftMangle.cpp?rev=240453&r1=240452&r2=240453&view=diff ============================================================================== --- cfe/trunk/lib/AST/MicrosoftMangle.cpp (original) +++ cfe/trunk/lib/AST/MicrosoftMangle.cpp Tue Jun 23 15:34:18 2015 @@ -502,6 +502,9 @@ void MicrosoftCXXNameMangler::mangleMemb FieldOffset /= getASTContext().getCharWidth(); VBTableOffset = 0; + + if (IM == MSInheritanceAttr::Keyword_virtual_inheritance) + FieldOffset -= getASTContext().getOffsetOfBaseWithVBPtr(RD).getQuantity(); } else { FieldOffset = RD->nullFieldOffsetIsZero() ? 0 : -1; @@ -570,6 +573,10 @@ MicrosoftCXXNameMangler::mangleMemberFun mangleName(MD); mangleFunctionEncoding(MD, /*ShouldMangle=*/true); } + + if (VBTableOffset == 0 && + IM == MSInheritanceAttr::Keyword_virtual_inheritance) + NVOffset -= getASTContext().getOffsetOfBaseWithVBPtr(RD).getQuantity(); } else { // Null single inheritance member functions are encoded as a simple nullptr. if (IM == MSInheritanceAttr::Keyword_single_inheritance) { @@ -582,7 +589,7 @@ MicrosoftCXXNameMangler::mangleMemberFun } if (MSInheritanceAttr::hasNVOffsetField(/*IsMemberFunction=*/true, IM)) - mangleNumber(NVOffset); + mangleNumber(static_cast<uint32_t>(NVOffset)); if (MSInheritanceAttr::hasVBPtrOffsetField(IM)) mangleNumber(VBPtrOffset); if (MSInheritanceAttr::hasVBTableOffsetField(IM)) Modified: cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp?rev=240453&r1=240452&r2=240453&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp (original) +++ cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp Tue Jun 23 15:34:18 2015 @@ -2514,33 +2514,13 @@ MicrosoftCXXABI::EmitFullMemberPointer(l return llvm::ConstantStruct::getAnon(fields); } -// Loading virtual member pointers using the virtual inheritance model -// always results in an adjustment using the vbtable even if the index is -// zero. -// -// This is usually OK because the first slot in the vbtable points -// backwards to the top of the MDC. However, the MDC might be reusing a -// vbptr from an nv-base. In this case, the first slot in the vbtable -// points to the start of the nv-base which introduced the vbptr and *not* -// the MDC. Modify the NonVirtualBaseAdjustment to account for this. -static CharUnits computeOffsetOfBaseWithVBPtr(const ASTContext &Ctx, - const CXXRecordDecl *RD) { - CharUnits Offset = CharUnits::Zero(); - const ASTRecordLayout *Layout = &Ctx.getASTRecordLayout(RD); - while (const CXXRecordDecl *Base = Layout->getBaseSharingVBPtr()) { - Offset += Layout->getBaseClassOffset(Base); - Layout = &Ctx.getASTRecordLayout(Base); - } - return Offset; -} - llvm::Constant * MicrosoftCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, CharUnits offset) { const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl(); if (RD->getMSInheritanceModel() == MSInheritanceAttr::Keyword_virtual_inheritance) - offset -= computeOffsetOfBaseWithVBPtr(getContext(), RD); + offset -= getContext().getOffsetOfBaseWithVBPtr(RD); llvm::Constant *FirstField = llvm::ConstantInt::get(CGM.IntTy, offset.getQuantity()); return EmitFullMemberPointer(FirstField, /*IsMemberFunction=*/false, RD, @@ -2639,7 +2619,7 @@ MicrosoftCXXABI::EmitMemberFunctionPoint if (VBTableIndex == 0 && RD->getMSInheritanceModel() == MSInheritanceAttr::Keyword_virtual_inheritance) - NonVirtualBaseAdjustment -= computeOffsetOfBaseWithVBPtr(getContext(), RD); + NonVirtualBaseAdjustment -= getContext().getOffsetOfBaseWithVBPtr(RD); // The rest of the fields are common with data member pointers. FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy); @@ -2987,7 +2967,7 @@ MicrosoftCXXABI::EmitMemberPointerConver Builder.CreateICmpEQ(VirtualBaseAdjustmentOffset, getZeroInt()); if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) { if (int64_t SrcOffsetToFirstVBase = - computeOffsetOfBaseWithVBPtr(getContext(), SrcRD).getQuantity()) { + getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()) { llvm::Value *UndoSrcAdjustment = Builder.CreateSelect( SrcVBIndexEqZero, llvm::ConstantInt::get(CGM.IntTy, SrcOffsetToFirstVBase), @@ -3049,7 +3029,7 @@ MicrosoftCXXABI::EmitMemberPointerConver // virtual base and the top of the MDC. if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) { if (int64_t DstOffsetToFirstVBase = - computeOffsetOfBaseWithVBPtr(getContext(), DstRD).getQuantity()) { + getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()) { llvm::Value *DoDstAdjustment = Builder.CreateSelect( DstVBIndexEqZero, llvm::ConstantInt::get(CGM.IntTy, DstOffsetToFirstVBase), @@ -3155,8 +3135,7 @@ llvm::Constant *MicrosoftCXXABI::EmitMem llvm::ICmpInst::ICMP_EQ, VirtualBaseAdjustmentOffset, getZeroInt()); if (SrcInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) { llvm::Constant *SrcOffsetToFirstVBase = llvm::ConstantInt::get( - CGM.IntTy, - computeOffsetOfBaseWithVBPtr(getContext(), SrcRD).getQuantity()); + CGM.IntTy, getContext().getOffsetOfBaseWithVBPtr(SrcRD).getQuantity()); llvm::Constant *UndoSrcAdjustment = llvm::ConstantExpr::getSelect( SrcVBIndexEqZero, SrcOffsetToFirstVBase, getZeroInt()); NVAdjustField = @@ -3219,8 +3198,7 @@ llvm::Constant *MicrosoftCXXABI::EmitMem // virtual base and the top of the MDC. if (DstInheritance == MSInheritanceAttr::Keyword_virtual_inheritance) { llvm::Constant *DstOffsetToFirstVBase = llvm::ConstantInt::get( - CGM.IntTy, - computeOffsetOfBaseWithVBPtr(getContext(), DstRD).getQuantity()); + CGM.IntTy, getContext().getOffsetOfBaseWithVBPtr(DstRD).getQuantity()); llvm::Constant *DoDstAdjustment = llvm::ConstantExpr::getSelect( DstVBIndexEqZero, DstOffsetToFirstVBase, getZeroInt()); NVAdjustField = Modified: cfe/trunk/test/CodeGenCXX/mangle-ms-templates-memptrs.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/mangle-ms-templates-memptrs.cpp?rev=240453&r1=240452&r2=240453&view=diff ============================================================================== --- cfe/trunk/test/CodeGenCXX/mangle-ms-templates-memptrs.cpp (original) +++ cfe/trunk/test/CodeGenCXX/mangle-ms-templates-memptrs.cpp Tue Jun 23 15:34:18 2015 @@ -141,3 +141,15 @@ void CallMethods() { // CHECK: call {{.*}} @"\01??$CallMethod@UM@@$0A@@@YAXAAUM@@@Z" // CHECK: call {{.*}} @"\01??$CallMethod@UV@@$0A@@@YAXAAUV@@@Z" // CHECK: call {{.*}} @"\01??$CallMethod@UU@@$0A@@@YAXAAUU@@@Z" + +namespace NegativeNVOffset { +struct A {}; +struct B : virtual A {}; +struct C : B { + virtual void f(); +}; +} + +template void CallMethod<NegativeNVOffset::C, &NegativeNVOffset::C::f>(NegativeNVOffset::C &); + +// CHECK-LABEL: define {{.*}} @"\01??$CallMethod@UC@NegativeNVOffset@@$I??_912@$BA@AEPPPPPPPM@A@@@YAXAAUC@NegativeNVOffset@@@Z" _______________________________________________ cfe-commits mailing list cfe-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits