diff options
Diffstat (limited to 'lib/CodeGen/CGClass.cpp')
| -rw-r--r-- | lib/CodeGen/CGClass.cpp | 414 |
1 files changed, 279 insertions, 135 deletions
diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp index d72eda95d7cf..cd75da276287 100644 --- a/lib/CodeGen/CGClass.cpp +++ b/lib/CodeGen/CGClass.cpp @@ -24,35 +24,36 @@ #include "clang/Basic/TargetBuiltins.h" #include "clang/CodeGen/CGFunctionInfo.h" #include "clang/Frontend/CodeGenOptions.h" +#include "llvm/IR/Intrinsics.h" using namespace clang; using namespace CodeGen; -static CharUnits -ComputeNonVirtualBaseClassOffset(ASTContext &Context, +static CharUnits +ComputeNonVirtualBaseClassOffset(ASTContext &Context, const CXXRecordDecl *DerivedClass, CastExpr::path_const_iterator Start, CastExpr::path_const_iterator End) { CharUnits Offset = CharUnits::Zero(); - + const CXXRecordDecl *RD = DerivedClass; - + for (CastExpr::path_const_iterator I = Start; I != End; ++I) { const CXXBaseSpecifier *Base = *I; assert(!Base->isVirtual() && "Should not see virtual bases here!"); // Get the layout. const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); - - const CXXRecordDecl *BaseDecl = + + const CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl()); - + // Add the offset. Offset += Layout.getBaseClassOffset(BaseDecl); - + RD = BaseDecl; } - + return Offset; } @@ -62,15 +63,15 @@ CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl, CastExpr::path_const_iterator PathEnd) { assert(PathBegin != PathEnd && "Base path should not be empty!"); - CharUnits Offset = + CharUnits Offset = ComputeNonVirtualBaseClassOffset(getContext(), ClassDecl, PathBegin, PathEnd); if (Offset.isZero()) return nullptr; - llvm::Type *PtrDiffTy = + llvm::Type *PtrDiffTy = Types.ConvertType(getContext().getPointerDiffType()); - + return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity()); } @@ -127,7 +128,7 @@ ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, llvm::Value *ptr, } else { baseOffset = virtualOffset; } - + // Apply the base offset. ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy); ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr"); @@ -149,7 +150,7 @@ llvm::Value *CodeGenFunction::GetAddressOfBaseClass( // *start* with a step down to the correct virtual base subobject, // and hence will not require any further steps. if ((*Start)->isVirtual()) { - VBase = + VBase = cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl()); ++Start; } @@ -157,7 +158,7 @@ llvm::Value *CodeGenFunction::GetAddressOfBaseClass( // Compute the static offset of the ultimate destination within its // allocating subobject (the virtual base, if there is one, or else // the "complete" object that we see). - CharUnits NonVirtualOffset = + CharUnits NonVirtualOffset = ComputeNonVirtualBaseClassOffset(getContext(), VBase ? VBase : Derived, Start, PathEnd); @@ -172,7 +173,7 @@ llvm::Value *CodeGenFunction::GetAddressOfBaseClass( } // Get the base pointer type. - llvm::Type *BasePtrTy = + llvm::Type *BasePtrTy = ConvertType((PathEnd[-1])->getType())->getPointerTo(); QualType DerivedTy = getContext().getRecordType(Derived); @@ -197,7 +198,7 @@ llvm::Value *CodeGenFunction::GetAddressOfBaseClass( origBB = Builder.GetInsertBlock(); llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull"); endBB = createBasicBlock("cast.end"); - + llvm::Value *isNull = Builder.CreateIsNull(Value); Builder.CreateCondBr(isNull, endBB, notNullBB); EmitBlock(notNullBB); @@ -216,10 +217,10 @@ llvm::Value *CodeGenFunction::GetAddressOfBaseClass( } // Apply both offsets. - Value = ApplyNonVirtualAndVirtualOffset(*this, Value, + Value = ApplyNonVirtualAndVirtualOffset(*this, Value, NonVirtualOffset, VirtualOffset); - + // Cast to the destination type. Value = Builder.CreateBitCast(Value, BasePtrTy); @@ -228,13 +229,13 @@ llvm::Value *CodeGenFunction::GetAddressOfBaseClass( llvm::BasicBlock *notNullBB = Builder.GetInsertBlock(); Builder.CreateBr(endBB); EmitBlock(endBB); - + llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result"); PHI->addIncoming(Value, notNullBB); PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB); Value = PHI; } - + return Value; } @@ -252,7 +253,7 @@ CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value, llvm::Value *NonVirtualOffset = CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd); - + if (!NonVirtualOffset) { // No offset, we can just cast back. return Builder.CreateBitCast(Value, DerivedPtrTy); @@ -266,12 +267,12 @@ CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value, CastNull = createBasicBlock("cast.null"); CastNotNull = createBasicBlock("cast.notnull"); CastEnd = createBasicBlock("cast.end"); - + llvm::Value *IsNull = Builder.CreateIsNull(Value); Builder.CreateCondBr(IsNull, CastNull, CastNotNull); EmitBlock(CastNotNull); } - + // Apply the offset. Value = Builder.CreateBitCast(Value, Int8PtrTy); Value = Builder.CreateGEP(Value, Builder.CreateNeg(NonVirtualOffset), @@ -285,14 +286,14 @@ CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value, EmitBlock(CastNull); Builder.CreateBr(CastEnd); EmitBlock(CastEnd); - + llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2); PHI->addIncoming(Value, CastNotNull); - PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), + PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull); Value = PHI; } - + return Value; } @@ -303,7 +304,7 @@ llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD, // This constructor/destructor does not need a VTT parameter. return nullptr; } - + const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->getParent(); const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent(); @@ -323,15 +324,15 @@ llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD, SubVTTIndex = 0; } else { const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD); - CharUnits BaseOffset = ForVirtualBase ? - Layout.getVBaseClassOffset(Base) : + CharUnits BaseOffset = ForVirtualBase ? + Layout.getVBaseClassOffset(Base) : Layout.getBaseClassOffset(Base); - SubVTTIndex = + SubVTTIndex = CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset)); assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!"); } - + if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) { // A VTT parameter was passed to the constructor, use it. VTT = LoadCXXVTT(); @@ -358,7 +359,7 @@ namespace { cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent(); const CXXDestructorDecl *D = BaseClass->getDestructor(); - llvm::Value *Addr = + llvm::Value *Addr = CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThis(), DerivedClass, BaseClass, BaseIsVirtual); @@ -391,7 +392,7 @@ static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) { return Checker.UsesThis; } -static void EmitBaseInitializer(CodeGenFunction &CGF, +static void EmitBaseInitializer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl, CXXCtorInitializer *BaseInit, CXXCtorType CtorType) { @@ -399,7 +400,7 @@ static void EmitBaseInitializer(CodeGenFunction &CGF, "Must have base initializer!"); llvm::Value *ThisPtr = CGF.LoadCXXThis(); - + const Type *BaseType = BaseInit->getBaseClass(); CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl()); @@ -418,7 +419,7 @@ static void EmitBaseInitializer(CodeGenFunction &CGF, // We can pretend to be a complete class because it only matters for // virtual bases, and we only do virtual bases for complete ctors. - llvm::Value *V = + llvm::Value *V = CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl, BaseClassDecl, isBaseVirtual); @@ -430,8 +431,8 @@ static void EmitBaseInitializer(CodeGenFunction &CGF, AggValueSlot::IsNotAliased); CGF.EmitAggExpr(BaseInit->getInit(), AggSlot); - - if (CGF.CGM.getLangOpts().Exceptions && + + if (CGF.CGM.getLangOpts().Exceptions && !BaseClassDecl->hasTrivialDestructor()) CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl, isBaseVirtual); @@ -490,17 +491,17 @@ static void EmitAggMemberInitializer(CodeGenFunction &CGF, llvm::Value *IndexVar = CGF.GetAddrOfLocalVar(ArrayIndexes[Index]); assert(IndexVar && "Array index variable not loaded"); - + // Initialize this index variable to zero. llvm::Value* Zero = llvm::Constant::getNullValue( CGF.ConvertType(CGF.getContext().getSizeType())); CGF.Builder.CreateStore(Zero, IndexVar); - + // Start the loop with a block that tests the condition. llvm::BasicBlock *CondBlock = CGF.createBasicBlock("for.cond"); llvm::BasicBlock *AfterFor = CGF.createBasicBlock("for.end"); - + CGF.EmitBlock(CondBlock); llvm::BasicBlock *ForBody = CGF.createBasicBlock("for.body"); @@ -512,7 +513,7 @@ static void EmitAggMemberInitializer(CodeGenFunction &CGF, llvm::ConstantInt::get(Counter->getType(), NumElements); llvm::Value *IsLess = CGF.Builder.CreateICmpULT(Counter, NumElementsPtr, "isless"); - + // If the condition is true, execute the body. CGF.Builder.CreateCondBr(IsLess, ForBody, AfterFor); @@ -539,6 +540,23 @@ static void EmitAggMemberInitializer(CodeGenFunction &CGF, CGF.EmitBlock(AfterFor, true); } +static bool isMemcpyEquivalentSpecialMember(const CXXMethodDecl *D) { + auto *CD = dyn_cast<CXXConstructorDecl>(D); + if (!(CD && CD->isCopyOrMoveConstructor()) && + !D->isCopyAssignmentOperator() && !D->isMoveAssignmentOperator()) + return false; + + // We can emit a memcpy for a trivial copy or move constructor/assignment. + if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding()) + return true; + + // We *must* emit a memcpy for a defaulted union copy or move op. + if (D->getParent()->isUnion() && D->isDefaulted()) + return true; + + return false; +} + static void EmitMemberInitializer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl, CXXCtorInitializer *MemberInit, @@ -548,7 +566,7 @@ static void EmitMemberInitializer(CodeGenFunction &CGF, assert(MemberInit->isAnyMemberInitializer() && "Must have member initializer!"); assert(MemberInit->getInit() && "Must have initializer!"); - + // non-static data member initializers. FieldDecl *Field = MemberInit->getAnyMember(); QualType FieldType = Field->getType(); @@ -580,14 +598,14 @@ static void EmitMemberInitializer(CodeGenFunction &CGF, QualType BaseElementTy = CGF.getContext().getBaseElementType(Array); CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit()); if (BaseElementTy.isPODType(CGF.getContext()) || - (CE && CE->getConstructor()->isTrivial())) { + (CE && isMemcpyEquivalentSpecialMember(CE->getConstructor()))) { unsigned SrcArgIndex = CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args); llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex])); LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy); LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field); - + // Copy the aggregate. CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType, LHS.isVolatileQualified()); @@ -621,28 +639,28 @@ void CodeGenFunction::EmitInitializerForField( llvm::Value *ArrayIndexVar = nullptr; if (ArrayIndexes.size()) { llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); - + // The LHS is a pointer to the first object we'll be constructing, as // a flat array. QualType BaseElementTy = getContext().getBaseElementType(FieldType); llvm::Type *BasePtr = ConvertType(BaseElementTy); BasePtr = llvm::PointerType::getUnqual(BasePtr); - llvm::Value *BaseAddrPtr = Builder.CreateBitCast(LHS.getAddress(), + llvm::Value *BaseAddrPtr = Builder.CreateBitCast(LHS.getAddress(), BasePtr); LHS = MakeAddrLValue(BaseAddrPtr, BaseElementTy); - + // Create an array index that will be used to walk over all of the // objects we're constructing. ArrayIndexVar = CreateTempAlloca(SizeTy, "object.index"); llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy); Builder.CreateStore(Zero, ArrayIndexVar); - - + + // Emit the block variables for the array indices, if any. for (unsigned I = 0, N = ArrayIndexes.size(); I != N; ++I) EmitAutoVarDecl(*ArrayIndexes[I]); } - + EmitAggMemberInitializer(*this, LHS, Init, ArrayIndexVar, FieldType, ArrayIndexes, 0); } @@ -762,9 +780,9 @@ void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) { if (PoisonSize < AsanAlignment || !SSV[i].Size || (NextField % AsanAlignment) != 0) continue; - Builder.CreateCall2( - F, Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)), - Builder.getIntN(PtrSize, PoisonSize)); + Builder.CreateCall( + F, {Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)), + Builder.getIntN(PtrSize, PoisonSize)}); } } @@ -796,8 +814,7 @@ void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) { if (IsTryBody) EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true); - RegionCounter Cnt = getPGORegionCounter(Body); - Cnt.beginRegion(Builder); + incrementProfileCounter(Body); RunCleanupsScope RunCleanups(*this); @@ -850,7 +867,7 @@ namespace { public: FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl, const VarDecl *SrcRec) - : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec), + : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec), RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)), FirstField(nullptr), LastField(nullptr), FirstFieldOffset(0), LastFieldOffset(0), LastAddedFieldIndex(0) {} @@ -876,7 +893,7 @@ namespace { unsigned LastFieldSize = LastField->isBitField() ? LastField->getBitWidthValue(CGF.getContext()) : - CGF.getContext().getTypeSize(LastField->getType()); + CGF.getContext().getTypeSize(LastField->getType()); uint64_t MemcpySizeBits = LastFieldOffset + LastFieldSize - FirstByteOffset + CGF.getContext().getCharWidth() - 1; @@ -1021,8 +1038,8 @@ namespace { QualType FieldType = Field->getType(); CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit()); - // Bail out on non-POD, not-trivially-constructable members. - if (!(CE && CE->getConstructor()->isTrivial()) && + // Bail out on non-memcpyable, not-trivially-copyable members. + if (!(CE && isMemcpyEquivalentSpecialMember(CE->getConstructor())) && !(FieldType.isTriviallyCopyableType(CGF.getContext()) || FieldType->isReferenceType())) return false; @@ -1127,9 +1144,7 @@ namespace { return Field; } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) { CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl()); - if (!(MD && (MD->isCopyAssignmentOperator() || - MD->isMoveAssignmentOperator()) && - MD->isTrivial())) + if (!(MD && isMemcpyEquivalentSpecialMember(MD))) return nullptr; MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument()); if (!IOA) @@ -1189,7 +1204,7 @@ namespace { if (F) { addMemcpyableField(F); AggregatedStmts.push_back(S); - } else { + } else { emitAggregatedStmts(); CGF.EmitStmt(S); } @@ -1274,7 +1289,7 @@ static bool FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field); static bool -HasTrivialDestructorBody(ASTContext &Context, +HasTrivialDestructorBody(ASTContext &Context, const CXXRecordDecl *BaseClassDecl, const CXXRecordDecl *MostDerivedClassDecl) { @@ -1309,7 +1324,7 @@ HasTrivialDestructorBody(ASTContext &Context, cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl()); if (!HasTrivialDestructorBody(Context, VirtualBase, MostDerivedClassDecl)) - return false; + return false; } } @@ -1325,7 +1340,7 @@ FieldHasTrivialDestructorBody(ASTContext &Context, const RecordType *RT = FieldBaseElementType->getAs<RecordType>(); if (!RT) return true; - + CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl()); return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl); } @@ -1351,6 +1366,10 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) { const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl()); CXXDtorType DtorType = CurGD.getDtorType(); + Stmt *Body = Dtor->getBody(); + if (Body) + incrementProfileCounter(Body); + // The call to operator delete in a deleting destructor happens // outside of the function-try-block, which means it's always // possible to delegate the destructor body to the complete @@ -1363,8 +1382,6 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) { return; } - Stmt *Body = Dtor->getBody(); - // If the body is a function-try-block, enter the try before // anything else. bool isTryBody = (Body && isa<CXXTryStmt>(Body)); @@ -1374,11 +1391,11 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) { // Enter the epilogue cleanups. RunCleanupsScope DtorEpilogue(*this); - + // If this is the complete variant, just invoke the base variant; // the epilogue will destruct the virtual bases. But we can't do // this optimization if the body is a function-try-block, because - // we'd introduce *two* handler blocks. In the Microsoft ABI, we + // we'd introduce *two* handler blocks. In the Microsoft ABI, we // always delegate because we might not have a definition in this TU. switch (DtorType) { case Dtor_Comdat: @@ -1399,13 +1416,10 @@ void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) { break; } // Fallthrough: act like we're in the base variant. - + case Dtor_Base: assert(Body); - RegionCounter Cnt = getPGORegionCounter(Body); - Cnt.beginRegion(Builder); - // Enter the cleanup scopes for fields and non-virtual bases. EnterDtorCleanups(Dtor, Dtor_Base); @@ -1447,7 +1461,7 @@ void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) AssignmentMemcpyizer AM(*this, AssignOp, Args); for (auto *I : RootCS->body()) - AM.emitAssignment(I); + AM.emitAssignment(I); AM.finish(); } @@ -1508,7 +1522,7 @@ namespace { LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy); LValue LV = CGF.EmitLValueForField(ThisLV, field); assert(LV.isSimple()); - + CGF.emitDestroy(LV.getAddress(), field->getType(), destroyer, flags.isForNormalCleanup() && useEHCleanupForArray); } @@ -1526,7 +1540,7 @@ void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD, // The deleting-destructor phase just needs to call the appropriate // operator delete that Sema picked up. if (DtorType == Dtor_Deleting) { - assert(DD->getOperatorDelete() && + assert(DD->getOperatorDelete() && "operator delete missing - EnterDtorCleanups"); if (CXXStructorImplicitParamValue) { // If there is an implicit param to the deleting dtor, it's a boolean @@ -1553,7 +1567,7 @@ void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD, for (const auto &Base : ClassDecl->vbases()) { CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl()); - + // Ignore trivial destructors. if (BaseClassDecl->hasTrivialDestructor()) continue; @@ -1567,15 +1581,15 @@ void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD, } assert(DtorType == Dtor_Base); - + // Destroy non-virtual bases. for (const auto &Base : ClassDecl->bases()) { // Ignore virtual bases. if (Base.isVirtual()) continue; - + CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl(); - + // Ignore trivial destructors. if (BaseClassDecl->hasTrivialDestructor()) continue; @@ -1656,7 +1670,7 @@ void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor, zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB); EmitBlock(loopBB); } - + // Find the end of the array. llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements, "arrayctor.end"); @@ -1676,15 +1690,15 @@ void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor, // Zero initialize the storage, if requested. if (zeroInitialize) EmitNullInitialization(cur, type); - - // C++ [class.temporary]p4: + + // C++ [class.temporary]p4: // There are two contexts in which temporaries are destroyed at a different // point than the end of the full-expression. The first context is when a - // default constructor is called to initialize an element of an array. - // If the constructor has one or more default arguments, the destruction of - // every temporary created in a default argument expression is sequenced + // default constructor is called to initialize an element of an array. + // If the constructor has one or more default arguments, the destruction of + // every temporary created in a default argument expression is sequenced // before the construction of the next array element, if any. - + { RunCleanupsScope Scope(*this); @@ -1733,33 +1747,32 @@ void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D, bool ForVirtualBase, bool Delegating, llvm::Value *This, const CXXConstructExpr *E) { - // If this is a trivial constructor, just emit what's needed. - if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding()) { - if (E->getNumArgs() == 0) { - // Trivial default constructor, no codegen required. - assert(D->isDefaultConstructor() && - "trivial 0-arg ctor not a default ctor"); - return; - } + // C++11 [class.mfct.non-static]p2: + // If a non-static member function of a class X is called for an object that + // is not of type X, or of a type derived from X, the behavior is undefined. + // FIXME: Provide a source location here. + EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, SourceLocation(), This, + getContext().getRecordType(D->getParent())); + + if (D->isTrivial() && D->isDefaultConstructor()) { + assert(E->getNumArgs() == 0 && "trivial default ctor with args"); + return; + } + // If this is a trivial constructor, just emit what's needed. If this is a + // union copy constructor, we must emit a memcpy, because the AST does not + // model that copy. + if (isMemcpyEquivalentSpecialMember(D)) { assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); - assert(D->isCopyOrMoveConstructor() && - "trivial 1-arg ctor not a copy/move ctor"); const Expr *Arg = E->getArg(0); - QualType Ty = Arg->getType(); + QualType SrcTy = Arg->getType(); llvm::Value *Src = EmitLValue(Arg).getAddress(); - EmitAggregateCopy(This, Src, Ty); + QualType DestTy = getContext().getTypeDeclType(D->getParent()); + EmitAggregateCopyCtor(This, Src, DestTy, SrcTy); return; } - // C++11 [class.mfct.non-static]p2: - // If a non-static member function of a class X is called for an object that - // is not of type X, or of a type derived from X, the behavior is undefined. - // FIXME: Provide a source location here. - EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, SourceLocation(), This, - getContext().getRecordType(D->getParent())); - CallArgList Args; // Push the this ptr. @@ -1784,25 +1797,26 @@ void CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D, llvm::Value *This, llvm::Value *Src, const CXXConstructExpr *E) { - if (D->isTrivial() && - !D->getParent()->mayInsertExtraPadding()) { + if (isMemcpyEquivalentSpecialMember(D)) { assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); assert(D->isCopyOrMoveConstructor() && "trivial 1-arg ctor not a copy/move ctor"); - EmitAggregateCopy(This, Src, E->arg_begin()->getType()); + EmitAggregateCopyCtor(This, Src, + getContext().getTypeDeclType(D->getParent()), + E->arg_begin()->getType()); return; } llvm::Value *Callee = CGM.getAddrOfCXXStructor(D, StructorType::Complete); assert(D->isInstance() && "Trying to emit a member call expr on a static method!"); - + const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>(); - + CallArgList Args; - + // Push the this ptr. Args.add(RValue::get(This), D->getThisType(getContext())); - + // Push the src ptr. QualType QT = *(FPT->param_type_begin()); llvm::Type *t = CGM.getTypes().ConvertType(QT); @@ -1945,10 +1959,18 @@ void CodeGenFunction::PushDestructorCleanup(QualType T, llvm::Value *Addr) { } void -CodeGenFunction::InitializeVTablePointer(BaseSubobject Base, +CodeGenFunction::InitializeVTablePointer(BaseSubobject Base, const CXXRecordDecl *NearestVBase, CharUnits OffsetFromNearestVBase, const CXXRecordDecl *VTableClass) { + const CXXRecordDecl *RD = Base.getBase(); + + // Don't initialize the vtable pointer if the class is marked with the + // 'novtable' attribute. + if ((RD == VTableClass || RD == NearestVBase) && + VTableClass->hasAttr<MSNoVTableAttr>()) + return; + // Compute the address point. bool NeedsVirtualOffset; llvm::Value *VTableAddressPoint = @@ -1960,7 +1982,7 @@ CodeGenFunction::InitializeVTablePointer(BaseSubobject Base, // Compute where to store the address point. llvm::Value *VirtualOffset = nullptr; CharUnits NonVirtualOffset = CharUnits::Zero(); - + if (NeedsVirtualOffset) { // We need to use the virtual base offset offset because the virtual base // might have a different offset in the most derived class. @@ -1973,12 +1995,12 @@ CodeGenFunction::InitializeVTablePointer(BaseSubobject Base, // We can just use the base offset in the complete class. NonVirtualOffset = Base.getBaseOffset(); } - + // Apply the offsets. llvm::Value *VTableField = LoadCXXThis(); - + if (!NonVirtualOffset.isZero() || VirtualOffset) - VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField, + VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField, NonVirtualOffset, VirtualOffset); @@ -1995,7 +2017,7 @@ CodeGenFunction::InitializeVTablePointer(BaseSubobject Base, } void -CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, +CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, const CXXRecordDecl *NearestVBase, CharUnits OffsetFromNearestVBase, bool BaseIsNonVirtualPrimaryBase, @@ -2008,7 +2030,7 @@ CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, InitializeVTablePointer(Base, NearestVBase, OffsetFromNearestVBase, VTableClass); } - + const CXXRecordDecl *RD = Base.getBase(); // Traverse bases. @@ -2029,7 +2051,7 @@ CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, if (!VBases.insert(BaseDecl).second) continue; - const ASTRecordLayout &Layout = + const ASTRecordLayout &Layout = getContext().getASTRecordLayout(VTableClass); BaseOffset = Layout.getVBaseClassOffset(BaseDecl); @@ -2039,15 +2061,15 @@ CodeGenFunction::InitializeVTablePointers(BaseSubobject Base, const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD); BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl); - BaseOffsetFromNearestVBase = + BaseOffsetFromNearestVBase = OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl); BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl; } - - InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset), + + InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset), I.isVirtual() ? BaseDecl : NearestVBase, BaseOffsetFromNearestVBase, - BaseDeclIsNonVirtualPrimaryBase, + BaseDeclIsNonVirtualPrimaryBase, VTableClass, VBases); } } @@ -2059,7 +2081,7 @@ void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) { // Initialize the vtable pointers for this class and all of its bases. VisitedVirtualBasesSetTy VBases; - InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()), + InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()), /*NearestVBase=*/nullptr, /*OffsetFromNearestVBase=*/CharUnits::Zero(), /*BaseIsNonVirtualPrimaryBase=*/false, RD, VBases); @@ -2076,6 +2098,128 @@ llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This, return VTable; } +// If a class has a single non-virtual base and does not introduce or override +// virtual member functions or fields, it will have the same layout as its base. +// This function returns the least derived such class. +// +// Casting an instance of a base class to such a derived class is technically +// undefined behavior, but it is a relatively common hack for introducing member +// functions on class instances with specific properties (e.g. llvm::Operator) +// that works under most compilers and should not have security implications, so +// we allow it by default. It can be disabled with -fsanitize=cfi-cast-strict. +static const CXXRecordDecl * +LeastDerivedClassWithSameLayout(const CXXRecordDecl *RD) { + if (!RD->field_empty()) + return RD; + + if (RD->getNumVBases() != 0) + return RD; + + if (RD->getNumBases() != 1) + return RD; + + for (const CXXMethodDecl *MD : RD->methods()) { + if (MD->isVirtual()) { + // Virtual member functions are only ok if they are implicit destructors + // because the implicit destructor will have the same semantics as the + // base class's destructor if no fields are added. + if (isa<CXXDestructorDecl>(MD) && MD->isImplicit()) + continue; + return RD; + } + } + + return LeastDerivedClassWithSameLayout( + RD->bases_begin()->getType()->getAsCXXRecordDecl()); +} + +void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXMethodDecl *MD, + llvm::Value *VTable) { + const CXXRecordDecl *ClassDecl = MD->getParent(); + if (!SanOpts.has(SanitizerKind::CFICastStrict)) + ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl); + + EmitVTablePtrCheck(ClassDecl, VTable); +} + +void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T, + llvm::Value *Derived, + bool MayBeNull) { + if (!getLangOpts().CPlusPlus) + return; + + auto *ClassTy = T->getAs<RecordType>(); + if (!ClassTy) + return; + + const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassTy->getDecl()); + + if (!ClassDecl->isCompleteDefinition() || !ClassDecl->isDynamicClass()) + return; + + SmallString<64> MangledName; + llvm::raw_svector_ostream Out(MangledName); + CGM.getCXXABI().getMangleContext().mangleCXXRTTI(T.getUnqualifiedType(), + Out); + + // Blacklist based on the mangled type. + if (CGM.getContext().getSanitizerBlacklist().isBlacklistedType(Out.str())) + return; + + if (!SanOpts.has(SanitizerKind::CFICastStrict)) + ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl); + + llvm::BasicBlock *ContBlock = 0; + + if (MayBeNull) { + llvm::Value *DerivedNotNull = + Builder.CreateIsNotNull(Derived, "cast.nonnull"); + + llvm::BasicBlock *CheckBlock = createBasicBlock("cast.check"); + ContBlock = createBasicBlock("cast.cont"); + + Builder.CreateCondBr(DerivedNotNull, CheckBlock, ContBlock); + + EmitBlock(CheckBlock); + } + + llvm::Value *VTable = GetVTablePtr(Derived, Int8PtrTy); + EmitVTablePtrCheck(ClassDecl, VTable); + + if (MayBeNull) { + Builder.CreateBr(ContBlock); + EmitBlock(ContBlock); + } +} + +void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD, + llvm::Value *VTable) { + // FIXME: Add blacklisting scheme. + if (RD->isInStdNamespace()) + return; + + std::string OutName; + llvm::raw_string_ostream Out(OutName); + CGM.getCXXABI().getMangleContext().mangleCXXVTableBitSet(RD, Out); + + llvm::Value *BitSetName = llvm::MetadataAsValue::get( + getLLVMContext(), llvm::MDString::get(getLLVMContext(), Out.str())); + + llvm::Value *BitSetTest = Builder.CreateCall( + CGM.getIntrinsic(llvm::Intrinsic::bitset_test), + {Builder.CreateBitCast(VTable, CGM.Int8PtrTy), BitSetName}); + + llvm::BasicBlock *ContBlock = createBasicBlock("vtable.check.cont"); + llvm::BasicBlock *TrapBlock = createBasicBlock("vtable.check.trap"); + + Builder.CreateCondBr(BitSetTest, ContBlock, TrapBlock); + + EmitBlock(TrapBlock); + Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap), {}); + Builder.CreateUnreachable(); + + EmitBlock(ContBlock); +} // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do // quite what we want. @@ -2140,7 +2284,7 @@ CodeGenFunction::CanDevirtualizeMemberFunctionCall(const Expr *Base, // This is a record decl. We know the type and can devirtualize it. return VD->getType()->isRecordType(); } - + return false; } @@ -2154,14 +2298,14 @@ CodeGenFunction::CanDevirtualizeMemberFunctionCall(const Expr *Base, // We can always devirtualize calls on temporary object expressions. if (isa<CXXConstructExpr>(Base)) return true; - + // And calls on bound temporaries. if (isa<CXXBindTemporaryExpr>(Base)) return true; - + // Check if this is a call expr that returns a record type. if (const CallExpr *CE = dyn_cast<CallExpr>(Base)) - return CE->getCallReturnType()->isRecordType(); + return CE->getCallReturnType(getContext())->isRecordType(); // We can't devirtualize the call. return false; @@ -2190,7 +2334,7 @@ void CodeGenFunction::EmitForwardingCallToLambda( // We don't need to separately arrange the call arguments because // the call can't be variadic anyway --- it's impossible to forward // variadic arguments. - + // Now emit our call. RValue RV = EmitCall(calleeFnInfo, callee, returnSlot, callArgs, callOperator); @@ -2218,7 +2362,7 @@ void CodeGenFunction::EmitLambdaBlockInvokeBody() { for (auto param : BD->params()) EmitDelegateCallArg(CallArgs, param, param->getLocStart()); - assert(!Lambda->isGenericLambda() && + assert(!Lambda->isGenericLambda() && "generic lambda interconversion to block not implemented"); EmitForwardingCallToLambda(Lambda->getLambdaCallOperator(), CallArgs); } @@ -2256,7 +2400,7 @@ void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) { const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs(); FunctionTemplateDecl *CallOpTemplate = CallOp->getDescribedFunctionTemplate(); void *InsertPos = nullptr; - FunctionDecl *CorrespondingCallOpSpecialization = + FunctionDecl *CorrespondingCallOpSpecialization = CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos); assert(CorrespondingCallOpSpecialization); CallOp = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization); |