aboutsummaryrefslogtreecommitdiff
path: root/lib/CodeGen/CGExprScalar.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/CodeGen/CGExprScalar.cpp')
-rw-r--r--lib/CodeGen/CGExprScalar.cpp223
1 files changed, 161 insertions, 62 deletions
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index 3d082de2a14f..55a413a2a717 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -294,8 +294,7 @@ public:
Value *AlignmentValue = CGF.EmitScalarExpr(AVAttr->getAlignment());
llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(AlignmentValue);
- CGF.EmitAlignmentAssumption(V, E, AVAttr->getLocation(),
- AlignmentCI->getZExtValue());
+ CGF.EmitAlignmentAssumption(V, E, AVAttr->getLocation(), AlignmentCI);
}
/// EmitLoadOfLValue - Given an expression with complex type that represents a
@@ -674,6 +673,10 @@ public:
return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
}
+ Value *VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E) {
+ return Builder.getInt1(E->isSatisfied());
+ }
+
Value *VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
return llvm::ConstantInt::get(Builder.getInt32Ty(), E->getValue());
}
@@ -814,6 +817,10 @@ public:
Value *VisitBinPtrMemD(const Expr *E) { return EmitLoadOfLValue(E); }
Value *VisitBinPtrMemI(const Expr *E) { return EmitLoadOfLValue(E); }
+ Value *VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) {
+ return Visit(E->getSemanticForm());
+ }
+
// Other Operators.
Value *VisitBlockExpr(const BlockExpr *BE);
Value *VisitAbstractConditionalOperator(const AbstractConditionalOperator *);
@@ -1657,8 +1664,8 @@ Value *ScalarExprEmitter::VisitConvertVectorExpr(ConvertVectorExpr *E) {
if (SrcTy == DstTy)
return Src;
- QualType SrcEltType = SrcType->getAs<VectorType>()->getElementType(),
- DstEltType = DstType->getAs<VectorType>()->getElementType();
+ QualType SrcEltType = SrcType->castAs<VectorType>()->getElementType(),
+ DstEltType = DstType->castAs<VectorType>()->getElementType();
assert(SrcTy->isVectorTy() &&
"ConvertVector source IR type must be a vector");
@@ -2577,14 +2584,16 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
TestAndClearIgnoreResultAssign();
+ Value *Op = Visit(E->getSubExpr());
+
+ // Generate a unary FNeg for FP ops.
+ if (Op->getType()->isFPOrFPVectorTy())
+ return Builder.CreateFNeg(Op, "fneg");
+
// Emit unary minus with EmitSub so we handle overflow cases etc.
BinOpInfo BinOp;
- BinOp.RHS = Visit(E->getSubExpr());
-
- if (BinOp.RHS->getType()->isFPOrFPVectorTy())
- BinOp.LHS = llvm::ConstantFP::getZeroValueForNegation(BinOp.RHS->getType());
- else
- BinOp.LHS = llvm::Constant::getNullValue(BinOp.RHS->getType());
+ BinOp.RHS = Op;
+ BinOp.LHS = llvm::Constant::getNullValue(BinOp.RHS->getType());
BinOp.Ty = E->getType();
BinOp.Opcode = BO_Sub;
// FIXME: once UnaryOperator carries FPFeatures, copy it here.
@@ -2662,7 +2671,7 @@ Value *ScalarExprEmitter::VisitOffsetOfExpr(OffsetOfExpr *E) {
case OffsetOfNode::Field: {
FieldDecl *MemberDecl = ON.getField();
- RecordDecl *RD = CurrentType->getAs<RecordType>()->getDecl();
+ RecordDecl *RD = CurrentType->castAs<RecordType>()->getDecl();
const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD);
// Compute the index of the field in its parent.
@@ -2695,7 +2704,7 @@ Value *ScalarExprEmitter::VisitOffsetOfExpr(OffsetOfExpr *E) {
continue;
}
- RecordDecl *RD = CurrentType->getAs<RecordType>()->getDecl();
+ RecordDecl *RD = CurrentType->castAs<RecordType>()->getDecl();
const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD);
// Save the element type.
@@ -3745,7 +3754,7 @@ Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,
Value *FirstVecArg = LHS,
*SecondVecArg = RHS;
- QualType ElTy = LHSTy->getAs<VectorType>()->getElementType();
+ QualType ElTy = LHSTy->castAs<VectorType>()->getElementType();
const BuiltinType *BTy = ElTy->getAs<BuiltinType>();
BuiltinType::Kind ElementKind = BTy->getKind();
@@ -4414,8 +4423,8 @@ Value *ScalarExprEmitter::VisitAsTypeExpr(AsTypeExpr *E) {
return Src;
}
- return Src = createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(),
- Src, DstTy, "astype");
+ return createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(),
+ Src, DstTy, "astype");
}
Value *ScalarExprEmitter::VisitAtomicExpr(AtomicExpr *E) {
@@ -4533,32 +4542,43 @@ LValue CodeGenFunction::EmitCompoundAssignmentLValue(
llvm_unreachable("Unhandled compound assignment operator");
}
-Value *CodeGenFunction::EmitCheckedInBoundsGEP(Value *Ptr,
- ArrayRef<Value *> IdxList,
- bool SignedIndices,
- bool IsSubtraction,
- SourceLocation Loc,
- const Twine &Name) {
- Value *GEPVal = Builder.CreateInBoundsGEP(Ptr, IdxList, Name);
+struct GEPOffsetAndOverflow {
+ // The total (signed) byte offset for the GEP.
+ llvm::Value *TotalOffset;
+ // The offset overflow flag - true if the total offset overflows.
+ llvm::Value *OffsetOverflows;
+};
- // If the pointer overflow sanitizer isn't enabled, do nothing.
- if (!SanOpts.has(SanitizerKind::PointerOverflow))
- return GEPVal;
+/// Evaluate given GEPVal, which is either an inbounds GEP, or a constant,
+/// and compute the total offset it applies from it's base pointer BasePtr.
+/// Returns offset in bytes and a boolean flag whether an overflow happened
+/// during evaluation.
+static GEPOffsetAndOverflow EmitGEPOffsetInBytes(Value *BasePtr, Value *GEPVal,
+ llvm::LLVMContext &VMContext,
+ CodeGenModule &CGM,
+ CGBuilderTy Builder) {
+ const auto &DL = CGM.getDataLayout();
- // If the GEP has already been reduced to a constant, leave it be.
- if (isa<llvm::Constant>(GEPVal))
- return GEPVal;
+ // The total (signed) byte offset for the GEP.
+ llvm::Value *TotalOffset = nullptr;
- // Only check for overflows in the default address space.
- if (GEPVal->getType()->getPointerAddressSpace())
- return GEPVal;
+ // Was the GEP already reduced to a constant?
+ if (isa<llvm::Constant>(GEPVal)) {
+ // Compute the offset by casting both pointers to integers and subtracting:
+ // GEPVal = BasePtr + ptr(Offset) <--> Offset = int(GEPVal) - int(BasePtr)
+ Value *BasePtr_int =
+ Builder.CreatePtrToInt(BasePtr, DL.getIntPtrType(BasePtr->getType()));
+ Value *GEPVal_int =
+ Builder.CreatePtrToInt(GEPVal, DL.getIntPtrType(GEPVal->getType()));
+ TotalOffset = Builder.CreateSub(GEPVal_int, BasePtr_int);
+ return {TotalOffset, /*OffsetOverflows=*/Builder.getFalse()};
+ }
auto *GEP = cast<llvm::GEPOperator>(GEPVal);
+ assert(GEP->getPointerOperand() == BasePtr &&
+ "BasePtr must be the the base of the GEP.");
assert(GEP->isInBounds() && "Expected inbounds GEP");
- SanitizerScope SanScope(this);
- auto &VMContext = getLLVMContext();
- const auto &DL = CGM.getDataLayout();
auto *IntPtrTy = DL.getIntPtrType(GEP->getPointerOperandType());
// Grab references to the signed add/mul overflow intrinsics for intptr_t.
@@ -4568,8 +4588,6 @@ Value *CodeGenFunction::EmitCheckedInBoundsGEP(Value *Ptr,
auto *SMulIntrinsic =
CGM.getIntrinsic(llvm::Intrinsic::smul_with_overflow, IntPtrTy);
- // The total (signed) byte offset for the GEP.
- llvm::Value *TotalOffset = nullptr;
// The offset overflow flag - true if the total offset overflows.
llvm::Value *OffsetOverflows = Builder.getFalse();
@@ -4627,41 +4645,122 @@ Value *CodeGenFunction::EmitCheckedInBoundsGEP(Value *Ptr,
TotalOffset = eval(BO_Add, TotalOffset, LocalOffset);
}
- // Common case: if the total offset is zero, don't emit a check.
- if (TotalOffset == Zero)
+ return {TotalOffset, OffsetOverflows};
+}
+
+Value *
+CodeGenFunction::EmitCheckedInBoundsGEP(Value *Ptr, ArrayRef<Value *> IdxList,
+ bool SignedIndices, bool IsSubtraction,
+ SourceLocation Loc, const Twine &Name) {
+ Value *GEPVal = Builder.CreateInBoundsGEP(Ptr, IdxList, Name);
+
+ // If the pointer overflow sanitizer isn't enabled, do nothing.
+ if (!SanOpts.has(SanitizerKind::PointerOverflow))
+ return GEPVal;
+
+ llvm::Type *PtrTy = Ptr->getType();
+
+ // Perform nullptr-and-offset check unless the nullptr is defined.
+ bool PerformNullCheck = !NullPointerIsDefined(
+ Builder.GetInsertBlock()->getParent(), PtrTy->getPointerAddressSpace());
+ // Check for overflows unless the GEP got constant-folded,
+ // and only in the default address space
+ bool PerformOverflowCheck =
+ !isa<llvm::Constant>(GEPVal) && PtrTy->getPointerAddressSpace() == 0;
+
+ if (!(PerformNullCheck || PerformOverflowCheck))
+ return GEPVal;
+
+ const auto &DL = CGM.getDataLayout();
+
+ SanitizerScope SanScope(this);
+ llvm::Type *IntPtrTy = DL.getIntPtrType(PtrTy);
+
+ GEPOffsetAndOverflow EvaluatedGEP =
+ EmitGEPOffsetInBytes(Ptr, GEPVal, getLLVMContext(), CGM, Builder);
+
+ assert((!isa<llvm::Constant>(EvaluatedGEP.TotalOffset) ||
+ EvaluatedGEP.OffsetOverflows == Builder.getFalse()) &&
+ "If the offset got constant-folded, we don't expect that there was an "
+ "overflow.");
+
+ auto *Zero = llvm::ConstantInt::getNullValue(IntPtrTy);
+
+ // Common case: if the total offset is zero, and we are using C++ semantics,
+ // where nullptr+0 is defined, don't emit a check.
+ if (EvaluatedGEP.TotalOffset == Zero && CGM.getLangOpts().CPlusPlus)
return GEPVal;
// Now that we've computed the total offset, add it to the base pointer (with
// wrapping semantics).
- auto *IntPtr = Builder.CreatePtrToInt(GEP->getPointerOperand(), IntPtrTy);
- auto *ComputedGEP = Builder.CreateAdd(IntPtr, TotalOffset);
-
- // The GEP is valid if:
- // 1) The total offset doesn't overflow, and
- // 2) The sign of the difference between the computed address and the base
- // pointer matches the sign of the total offset.
- llvm::Value *ValidGEP;
- auto *NoOffsetOverflow = Builder.CreateNot(OffsetOverflows);
- if (SignedIndices) {
- auto *PosOrZeroValid = Builder.CreateICmpUGE(ComputedGEP, IntPtr);
- auto *PosOrZeroOffset = Builder.CreateICmpSGE(TotalOffset, Zero);
- llvm::Value *NegValid = Builder.CreateICmpULT(ComputedGEP, IntPtr);
- ValidGEP = Builder.CreateAnd(
- Builder.CreateSelect(PosOrZeroOffset, PosOrZeroValid, NegValid),
- NoOffsetOverflow);
- } else if (!SignedIndices && !IsSubtraction) {
- auto *PosOrZeroValid = Builder.CreateICmpUGE(ComputedGEP, IntPtr);
- ValidGEP = Builder.CreateAnd(PosOrZeroValid, NoOffsetOverflow);
- } else {
- auto *NegOrZeroValid = Builder.CreateICmpULE(ComputedGEP, IntPtr);
- ValidGEP = Builder.CreateAnd(NegOrZeroValid, NoOffsetOverflow);
+ auto *IntPtr = Builder.CreatePtrToInt(Ptr, IntPtrTy);
+ auto *ComputedGEP = Builder.CreateAdd(IntPtr, EvaluatedGEP.TotalOffset);
+
+ llvm::SmallVector<std::pair<llvm::Value *, SanitizerMask>, 2> Checks;
+
+ if (PerformNullCheck) {
+ // In C++, if the base pointer evaluates to a null pointer value,
+ // the only valid pointer this inbounds GEP can produce is also
+ // a null pointer, so the offset must also evaluate to zero.
+ // Likewise, if we have non-zero base pointer, we can not get null pointer
+ // as a result, so the offset can not be -intptr_t(BasePtr).
+ // In other words, both pointers are either null, or both are non-null,
+ // or the behaviour is undefined.
+ //
+ // C, however, is more strict in this regard, and gives more
+ // optimization opportunities: in C, additionally, nullptr+0 is undefined.
+ // So both the input to the 'gep inbounds' AND the output must not be null.
+ auto *BaseIsNotNullptr = Builder.CreateIsNotNull(Ptr);
+ auto *ResultIsNotNullptr = Builder.CreateIsNotNull(ComputedGEP);
+ auto *Valid =
+ CGM.getLangOpts().CPlusPlus
+ ? Builder.CreateICmpEQ(BaseIsNotNullptr, ResultIsNotNullptr)
+ : Builder.CreateAnd(BaseIsNotNullptr, ResultIsNotNullptr);
+ Checks.emplace_back(Valid, SanitizerKind::PointerOverflow);
+ }
+
+ if (PerformOverflowCheck) {
+ // The GEP is valid if:
+ // 1) The total offset doesn't overflow, and
+ // 2) The sign of the difference between the computed address and the base
+ // pointer matches the sign of the total offset.
+ llvm::Value *ValidGEP;
+ auto *NoOffsetOverflow = Builder.CreateNot(EvaluatedGEP.OffsetOverflows);
+ if (SignedIndices) {
+ // GEP is computed as `unsigned base + signed offset`, therefore:
+ // * If offset was positive, then the computed pointer can not be
+ // [unsigned] less than the base pointer, unless it overflowed.
+ // * If offset was negative, then the computed pointer can not be
+ // [unsigned] greater than the bas pointere, unless it overflowed.
+ auto *PosOrZeroValid = Builder.CreateICmpUGE(ComputedGEP, IntPtr);
+ auto *PosOrZeroOffset =
+ Builder.CreateICmpSGE(EvaluatedGEP.TotalOffset, Zero);
+ llvm::Value *NegValid = Builder.CreateICmpULT(ComputedGEP, IntPtr);
+ ValidGEP =
+ Builder.CreateSelect(PosOrZeroOffset, PosOrZeroValid, NegValid);
+ } else if (!IsSubtraction) {
+ // GEP is computed as `unsigned base + unsigned offset`, therefore the
+ // computed pointer can not be [unsigned] less than base pointer,
+ // unless there was an overflow.
+ // Equivalent to `@llvm.uadd.with.overflow(%base, %offset)`.
+ ValidGEP = Builder.CreateICmpUGE(ComputedGEP, IntPtr);
+ } else {
+ // GEP is computed as `unsigned base - unsigned offset`, therefore the
+ // computed pointer can not be [unsigned] greater than base pointer,
+ // unless there was an overflow.
+ // Equivalent to `@llvm.usub.with.overflow(%base, sub(0, %offset))`.
+ ValidGEP = Builder.CreateICmpULE(ComputedGEP, IntPtr);
+ }
+ ValidGEP = Builder.CreateAnd(ValidGEP, NoOffsetOverflow);
+ Checks.emplace_back(ValidGEP, SanitizerKind::PointerOverflow);
}
+ assert(!Checks.empty() && "Should have produced some checks.");
+
llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc)};
// Pass the computed GEP to the runtime to avoid emitting poisoned arguments.
llvm::Value *DynamicArgs[] = {IntPtr, ComputedGEP};
- EmitCheck(std::make_pair(ValidGEP, SanitizerKind::PointerOverflow),
- SanitizerHandler::PointerOverflow, StaticArgs, DynamicArgs);
+ EmitCheck(Checks, SanitizerHandler::PointerOverflow, StaticArgs, DynamicArgs);
return GEPVal;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-22 20:23:42 +0000