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llvm-project/clang/lib/AST/ExprConstant.cpp
Richard Smith 725810a2bb Split apart the state accumulated during constant expression evaluation and the 
end result. Use this split to propagate state information and diagnostics
through more of constant expression evaluation.

llvm-svn: 142159
2011-10-16 21:26:27 +00:00

3191 lines
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//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Expr constant evaluator.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/APValue.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/ASTDiagnostic.h"
#include "clang/AST/Expr.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallString.h"
#include <cstring>
using namespace clang;
using llvm::APSInt;
using llvm::APFloat;
/// EvalInfo - This is a private struct used by the evaluator to capture
/// information about a subexpression as it is folded. It retains information
/// about the AST context, but also maintains information about the folded
/// expression.
///
/// If an expression could be evaluated, it is still possible it is not a C
/// "integer constant expression" or constant expression. If not, this struct
/// captures information about how and why not.
///
/// One bit of information passed *into* the request for constant folding
/// indicates whether the subexpression is "evaluated" or not according to C
/// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
/// evaluate the expression regardless of what the RHS is, but C only allows
/// certain things in certain situations.
namespace {
struct EvalInfo {
const ASTContext &Ctx;
/// EvalStatus - Contains information about the evaluation.
Expr::EvalStatus &EvalStatus;
typedef llvm::DenseMap<const OpaqueValueExpr*, APValue> MapTy;
MapTy OpaqueValues;
const APValue *getOpaqueValue(const OpaqueValueExpr *e) const {
MapTy::const_iterator i = OpaqueValues.find(e);
if (i == OpaqueValues.end()) return 0;
return &i->second;
}
EvalInfo(const ASTContext &C, Expr::EvalStatus &S)
: Ctx(C), EvalStatus(S) {}
const LangOptions &getLangOpts() { return Ctx.getLangOptions(); }
};
struct ComplexValue {
private:
bool IsInt;
public:
APSInt IntReal, IntImag;
APFloat FloatReal, FloatImag;
ComplexValue() : FloatReal(APFloat::Bogus), FloatImag(APFloat::Bogus) {}
void makeComplexFloat() { IsInt = false; }
bool isComplexFloat() const { return !IsInt; }
APFloat &getComplexFloatReal() { return FloatReal; }
APFloat &getComplexFloatImag() { return FloatImag; }
void makeComplexInt() { IsInt = true; }
bool isComplexInt() const { return IsInt; }
APSInt &getComplexIntReal() { return IntReal; }
APSInt &getComplexIntImag() { return IntImag; }
void moveInto(APValue &v) const {
if (isComplexFloat())
v = APValue(FloatReal, FloatImag);
else
v = APValue(IntReal, IntImag);
}
void setFrom(const APValue &v) {
assert(v.isComplexFloat() || v.isComplexInt());
if (v.isComplexFloat()) {
makeComplexFloat();
FloatReal = v.getComplexFloatReal();
FloatImag = v.getComplexFloatImag();
} else {
makeComplexInt();
IntReal = v.getComplexIntReal();
IntImag = v.getComplexIntImag();
}
}
};
struct LValue {
const Expr *Base;
CharUnits Offset;
const Expr *getLValueBase() { return Base; }
CharUnits getLValueOffset() { return Offset; }
void moveInto(APValue &v) const {
v = APValue(Base, Offset);
}
void setFrom(const APValue &v) {
assert(v.isLValue());
Base = v.getLValueBase();
Offset = v.getLValueOffset();
}
};
}
static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info);
static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info);
static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
EvalInfo &Info);
static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
//===----------------------------------------------------------------------===//
// Misc utilities
//===----------------------------------------------------------------------===//
static bool IsGlobalLValue(const Expr* E) {
if (!E) return true;
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
if (isa<FunctionDecl>(DRE->getDecl()))
return true;
if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
return VD->hasGlobalStorage();
return false;
}
if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(E))
return CLE->isFileScope();
return true;
}
static bool EvalPointerValueAsBool(LValue& Value, bool& Result) {
const Expr* Base = Value.Base;
// A null base expression indicates a null pointer. These are always
// evaluatable, and they are false unless the offset is zero.
if (!Base) {
Result = !Value.Offset.isZero();
return true;
}
// Require the base expression to be a global l-value.
if (!IsGlobalLValue(Base)) return false;
// We have a non-null base expression. These are generally known to
// be true, but if it'a decl-ref to a weak symbol it can be null at
// runtime.
Result = true;
const DeclRefExpr* DeclRef = dyn_cast<DeclRefExpr>(Base);
if (!DeclRef)
return true;
// If it's a weak symbol, it isn't constant-evaluable.
const ValueDecl* Decl = DeclRef->getDecl();
if (Decl->hasAttr<WeakAttr>() ||
Decl->hasAttr<WeakRefAttr>() ||
Decl->isWeakImported())
return false;
return true;
}
static bool HandleConversionToBool(const Expr* E, bool& Result,
EvalInfo &Info) {
if (E->getType()->isIntegralOrEnumerationType()) {
APSInt IntResult;
if (!EvaluateInteger(E, IntResult, Info))
return false;
Result = IntResult != 0;
return true;
} else if (E->getType()->isRealFloatingType()) {
APFloat FloatResult(0.0);
if (!EvaluateFloat(E, FloatResult, Info))
return false;
Result = !FloatResult.isZero();
return true;
} else if (E->getType()->hasPointerRepresentation()) {
LValue PointerResult;
if (!EvaluatePointer(E, PointerResult, Info))
return false;
return EvalPointerValueAsBool(PointerResult, Result);
} else if (E->getType()->isAnyComplexType()) {
ComplexValue ComplexResult;
if (!EvaluateComplex(E, ComplexResult, Info))
return false;
if (ComplexResult.isComplexFloat()) {
Result = !ComplexResult.getComplexFloatReal().isZero() ||
!ComplexResult.getComplexFloatImag().isZero();
} else {
Result = ComplexResult.getComplexIntReal().getBoolValue() ||
ComplexResult.getComplexIntImag().getBoolValue();
}
return true;
}
return false;
}
static APSInt HandleFloatToIntCast(QualType DestType, QualType SrcType,
APFloat &Value, const ASTContext &Ctx) {
unsigned DestWidth = Ctx.getIntWidth(DestType);
// Determine whether we are converting to unsigned or signed.
bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
// FIXME: Warning for overflow.
APSInt Result(DestWidth, !DestSigned);
bool ignored;
(void)Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored);
return Result;
}
static APFloat HandleFloatToFloatCast(QualType DestType, QualType SrcType,
APFloat &Value, const ASTContext &Ctx) {
bool ignored;
APFloat Result = Value;
Result.convert(Ctx.getFloatTypeSemantics(DestType),
APFloat::rmNearestTiesToEven, &ignored);
return Result;
}
static APSInt HandleIntToIntCast(QualType DestType, QualType SrcType,
APSInt &Value, const ASTContext &Ctx) {
unsigned DestWidth = Ctx.getIntWidth(DestType);
APSInt Result = Value;
// Figure out if this is a truncate, extend or noop cast.
// If the input is signed, do a sign extend, noop, or truncate.
Result = Result.extOrTrunc(DestWidth);
Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
return Result;
}
static APFloat HandleIntToFloatCast(QualType DestType, QualType SrcType,
APSInt &Value, const ASTContext &Ctx) {
APFloat Result(Ctx.getFloatTypeSemantics(DestType), 1);
Result.convertFromAPInt(Value, Value.isSigned(),
APFloat::rmNearestTiesToEven);
return Result;
}
namespace {
class HasSideEffect
: public ConstStmtVisitor<HasSideEffect, bool> {
const ASTContext &Ctx;
public:
HasSideEffect(const ASTContext &C) : Ctx(C) {}
// Unhandled nodes conservatively default to having side effects.
bool VisitStmt(const Stmt *S) {
return true;
}
bool VisitParenExpr(const ParenExpr *E) { return Visit(E->getSubExpr()); }
bool VisitGenericSelectionExpr(const GenericSelectionExpr *E) {
return Visit(E->getResultExpr());
}
bool VisitDeclRefExpr(const DeclRefExpr *E) {
if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
return true;
return false;
}
bool VisitObjCIvarRefExpr(const ObjCIvarRefExpr *E) {
if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
return true;
return false;
}
bool VisitBlockDeclRefExpr (const BlockDeclRefExpr *E) {
if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
return true;
return false;
}
// We don't want to evaluate BlockExprs multiple times, as they generate
// a ton of code.
bool VisitBlockExpr(const BlockExpr *E) { return true; }
bool VisitPredefinedExpr(const PredefinedExpr *E) { return false; }
bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E)
{ return Visit(E->getInitializer()); }
bool VisitMemberExpr(const MemberExpr *E) { return Visit(E->getBase()); }
bool VisitIntegerLiteral(const IntegerLiteral *E) { return false; }
bool VisitFloatingLiteral(const FloatingLiteral *E) { return false; }
bool VisitStringLiteral(const StringLiteral *E) { return false; }
bool VisitCharacterLiteral(const CharacterLiteral *E) { return false; }
bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E)
{ return false; }
bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E)
{ return Visit(E->getLHS()) || Visit(E->getRHS()); }
bool VisitChooseExpr(const ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Ctx)); }
bool VisitCastExpr(const CastExpr *E) { return Visit(E->getSubExpr()); }
bool VisitBinAssign(const BinaryOperator *E) { return true; }
bool VisitCompoundAssignOperator(const BinaryOperator *E) { return true; }
bool VisitBinaryOperator(const BinaryOperator *E)
{ return Visit(E->getLHS()) || Visit(E->getRHS()); }
bool VisitUnaryPreInc(const UnaryOperator *E) { return true; }
bool VisitUnaryPostInc(const UnaryOperator *E) { return true; }
bool VisitUnaryPreDec(const UnaryOperator *E) { return true; }
bool VisitUnaryPostDec(const UnaryOperator *E) { return true; }
bool VisitUnaryDeref(const UnaryOperator *E) {
if (Ctx.getCanonicalType(E->getType()).isVolatileQualified())
return true;
return Visit(E->getSubExpr());
}
bool VisitUnaryOperator(const UnaryOperator *E) { return Visit(E->getSubExpr()); }
// Has side effects if any element does.
bool VisitInitListExpr(const InitListExpr *E) {
for (unsigned i = 0, e = E->getNumInits(); i != e; ++i)
if (Visit(E->getInit(i))) return true;
if (const Expr *filler = E->getArrayFiller())
return Visit(filler);
return false;
}
bool VisitSizeOfPackExpr(const SizeOfPackExpr *) { return false; }
};
class OpaqueValueEvaluation {
EvalInfo &info;
OpaqueValueExpr *opaqueValue;
public:
OpaqueValueEvaluation(EvalInfo &info, OpaqueValueExpr *opaqueValue,
Expr *value)
: info(info), opaqueValue(opaqueValue) {
// If evaluation fails, fail immediately.
if (!Evaluate(info.OpaqueValues[opaqueValue], info, value)) {
this->opaqueValue = 0;
return;
}
}
bool hasError() const { return opaqueValue == 0; }
~OpaqueValueEvaluation() {
// FIXME: This will not work for recursive constexpr functions using opaque
// values. Restore the former value.
if (opaqueValue) info.OpaqueValues.erase(opaqueValue);
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Generic Evaluation
//===----------------------------------------------------------------------===//
namespace {
template <class Derived, typename RetTy=void>
class ExprEvaluatorBase
: public ConstStmtVisitor<Derived, RetTy> {
private:
RetTy DerivedSuccess(const APValue &V, const Expr *E) {
return static_cast<Derived*>(this)->Success(V, E);
}
RetTy DerivedError(const Expr *E) {
return static_cast<Derived*>(this)->Error(E);
}
RetTy DerivedValueInitialization(const Expr *E) {
return static_cast<Derived*>(this)->ValueInitialization(E);
}
protected:
EvalInfo &Info;
typedef ConstStmtVisitor<Derived, RetTy> StmtVisitorTy;
typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
RetTy ValueInitialization(const Expr *E) { return DerivedError(E); }
public:
ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
RetTy VisitStmt(const Stmt *) {
llvm_unreachable("Expression evaluator should not be called on stmts");
}
RetTy VisitExpr(const Expr *E) {
return DerivedError(E);
}
RetTy VisitParenExpr(const ParenExpr *E)
{ return StmtVisitorTy::Visit(E->getSubExpr()); }
RetTy VisitUnaryExtension(const UnaryOperator *E)
{ return StmtVisitorTy::Visit(E->getSubExpr()); }
RetTy VisitUnaryPlus(const UnaryOperator *E)
{ return StmtVisitorTy::Visit(E->getSubExpr()); }
RetTy VisitChooseExpr(const ChooseExpr *E)
{ return StmtVisitorTy::Visit(E->getChosenSubExpr(Info.Ctx)); }
RetTy VisitGenericSelectionExpr(const GenericSelectionExpr *E)
{ return StmtVisitorTy::Visit(E->getResultExpr()); }
RetTy VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
{ return StmtVisitorTy::Visit(E->getReplacement()); }
RetTy VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
OpaqueValueEvaluation opaque(Info, E->getOpaqueValue(), E->getCommon());
if (opaque.hasError())
return DerivedError(E);
bool cond;
if (!HandleConversionToBool(E->getCond(), cond, Info))
return DerivedError(E);
return StmtVisitorTy::Visit(cond ? E->getTrueExpr() : E->getFalseExpr());
}
RetTy VisitConditionalOperator(const ConditionalOperator *E) {
bool BoolResult;
if (!HandleConversionToBool(E->getCond(), BoolResult, Info))
return DerivedError(E);
Expr* EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
return StmtVisitorTy::Visit(EvalExpr);
}
RetTy VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
const APValue *value = Info.getOpaqueValue(E);
if (!value)
return (E->getSourceExpr() ? StmtVisitorTy::Visit(E->getSourceExpr())
: DerivedError(E));
return DerivedSuccess(*value, E);
}
RetTy VisitInitListExpr(const InitListExpr *E) {
if (Info.getLangOpts().CPlusPlus0x) {
if (E->getNumInits() == 0)
return DerivedValueInitialization(E);
if (E->getNumInits() == 1)
return StmtVisitorTy::Visit(E->getInit(0));
}
return DerivedError(E);
}
RetTy VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
return DerivedValueInitialization(E);
}
RetTy VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
return DerivedValueInitialization(E);
}
};
}
//===----------------------------------------------------------------------===//
// LValue Evaluation
//===----------------------------------------------------------------------===//
namespace {
class LValueExprEvaluator
: public ExprEvaluatorBase<LValueExprEvaluator, bool> {
LValue &Result;
const Decl *PrevDecl;
bool Success(const Expr *E) {
Result.Base = E;
Result.Offset = CharUnits::Zero();
return true;
}
public:
LValueExprEvaluator(EvalInfo &info, LValue &Result) :
ExprEvaluatorBaseTy(info), Result(Result), PrevDecl(0) {}
bool Success(const APValue &V, const Expr *E) {
Result.setFrom(V);
return true;
}
bool Error(const Expr *E) {
return false;
}
bool VisitDeclRefExpr(const DeclRefExpr *E);
bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
bool VisitMemberExpr(const MemberExpr *E);
bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
bool VisitUnaryDeref(const UnaryOperator *E);
bool VisitCastExpr(const CastExpr *E) {
switch (E->getCastKind()) {
default:
return false;
case CK_NoOp:
case CK_LValueBitCast:
return Visit(E->getSubExpr());
// FIXME: Support CK_DerivedToBase and friends.
}
}
// FIXME: Missing: __real__, __imag__
};
} // end anonymous namespace
static bool EvaluateLValue(const Expr* E, LValue& Result, EvalInfo &Info) {
return LValueExprEvaluator(Info, Result).Visit(E);
}
bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
if (isa<FunctionDecl>(E->getDecl())) {
return Success(E);
} else if (const VarDecl* VD = dyn_cast<VarDecl>(E->getDecl())) {
if (!VD->getType()->isReferenceType())
return Success(E);
// Reference parameters can refer to anything even if they have an
// "initializer" in the form of a default argument.
if (!isa<ParmVarDecl>(VD)) {
// FIXME: Check whether VD might be overridden!
// Check for recursive initializers of references.
if (PrevDecl == VD)
return Error(E);
PrevDecl = VD;
if (const Expr *Init = VD->getAnyInitializer())
return Visit(Init);
}
}
return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
}
bool
LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
return Success(E);
}
bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
QualType Ty;
if (E->isArrow()) {
if (!EvaluatePointer(E->getBase(), Result, Info))
return false;
Ty = E->getBase()->getType()->getAs<PointerType>()->getPointeeType();
} else {
if (!Visit(E->getBase()))
return false;
Ty = E->getBase()->getType();
}
const RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
if (!FD) // FIXME: deal with other kinds of member expressions
return false;
if (FD->getType()->isReferenceType())
return false;
unsigned i = FD->getFieldIndex();
Result.Offset += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
return true;
}
bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
if (!EvaluatePointer(E->getBase(), Result, Info))
return false;
APSInt Index;
if (!EvaluateInteger(E->getIdx(), Index, Info))
return false;
CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(E->getType());
Result.Offset += Index.getSExtValue() * ElementSize;
return true;
}
bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
return EvaluatePointer(E->getSubExpr(), Result, Info);
}
//===----------------------------------------------------------------------===//
// Pointer Evaluation
//===----------------------------------------------------------------------===//
namespace {
class PointerExprEvaluator
: public ExprEvaluatorBase<PointerExprEvaluator, bool> {
LValue &Result;
bool Success(const Expr *E) {
Result.Base = E;
Result.Offset = CharUnits::Zero();
return true;
}
public:
PointerExprEvaluator(EvalInfo &info, LValue &Result)
: ExprEvaluatorBaseTy(info), Result(Result) {}
bool Success(const APValue &V, const Expr *E) {
Result.setFrom(V);
return true;
}
bool Error(const Stmt *S) {
return false;
}
bool ValueInitialization(const Expr *E) {
return Success((Expr*)0);
}
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitCastExpr(const CastExpr* E);
bool VisitUnaryAddrOf(const UnaryOperator *E);
bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
{ return Success(E); }
bool VisitAddrLabelExpr(const AddrLabelExpr *E)
{ return Success(E); }
bool VisitCallExpr(const CallExpr *E);
bool VisitBlockExpr(const BlockExpr *E) {
if (!E->getBlockDecl()->hasCaptures())
return Success(E);
return false;
}
bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E)
{ return ValueInitialization(E); }
// FIXME: Missing: @protocol, @selector
};
} // end anonymous namespace
static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) {
assert(E->getType()->hasPointerRepresentation());
return PointerExprEvaluator(Info, Result).Visit(E);
}
bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->getOpcode() != BO_Add &&
E->getOpcode() != BO_Sub)
return false;
const Expr *PExp = E->getLHS();
const Expr *IExp = E->getRHS();
if (IExp->getType()->isPointerType())
std::swap(PExp, IExp);
if (!EvaluatePointer(PExp, Result, Info))
return false;
llvm::APSInt Offset;
if (!EvaluateInteger(IExp, Offset, Info))
return false;
int64_t AdditionalOffset
= Offset.isSigned() ? Offset.getSExtValue()
: static_cast<int64_t>(Offset.getZExtValue());
// Compute the new offset in the appropriate width.
QualType PointeeType =
PExp->getType()->getAs<PointerType>()->getPointeeType();
CharUnits SizeOfPointee;
// Explicitly handle GNU void* and function pointer arithmetic extensions.
if (PointeeType->isVoidType() || PointeeType->isFunctionType())
SizeOfPointee = CharUnits::One();
else
SizeOfPointee = Info.Ctx.getTypeSizeInChars(PointeeType);
if (E->getOpcode() == BO_Add)
Result.Offset += AdditionalOffset * SizeOfPointee;
else
Result.Offset -= AdditionalOffset * SizeOfPointee;
return true;
}
bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
return EvaluateLValue(E->getSubExpr(), Result, Info);
}
bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
const Expr* SubExpr = E->getSubExpr();
switch (E->getCastKind()) {
default:
break;
case CK_NoOp:
case CK_BitCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
return Visit(SubExpr);
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase: {
LValue BaseLV;
if (!EvaluatePointer(E->getSubExpr(), BaseLV, Info))
return false;
// Now figure out the necessary offset to add to the baseLV to get from
// the derived class to the base class.
CharUnits Offset = CharUnits::Zero();
QualType Ty = E->getSubExpr()->getType();
const CXXRecordDecl *DerivedDecl =
Ty->getAs<PointerType>()->getPointeeType()->getAsCXXRecordDecl();
for (CastExpr::path_const_iterator PathI = E->path_begin(),
PathE = E->path_end(); PathI != PathE; ++PathI) {
const CXXBaseSpecifier *Base = *PathI;
// FIXME: If the base is virtual, we'd need to determine the type of the
// most derived class and we don't support that right now.
if (Base->isVirtual())
return false;
const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
Offset += Layout.getBaseClassOffset(BaseDecl);
DerivedDecl = BaseDecl;
}
Result.Base = BaseLV.getLValueBase();
Result.Offset = BaseLV.getLValueOffset() + Offset;
return true;
}
case CK_NullToPointer: {
Result.Base = 0;
Result.Offset = CharUnits::Zero();
return true;
}
case CK_IntegralToPointer: {
APValue Value;
if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
break;
if (Value.isInt()) {
Value.getInt() = Value.getInt().extOrTrunc((unsigned)Info.Ctx.getTypeSize(E->getType()));
Result.Base = 0;
Result.Offset = CharUnits::fromQuantity(Value.getInt().getZExtValue());
return true;
} else {
// Cast is of an lvalue, no need to change value.
Result.Base = Value.getLValueBase();
Result.Offset = Value.getLValueOffset();
return true;
}
}
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
return EvaluateLValue(SubExpr, Result, Info);
}
return false;
}
bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
if (E->isBuiltinCall(Info.Ctx) ==
Builtin::BI__builtin___CFStringMakeConstantString ||
E->isBuiltinCall(Info.Ctx) ==
Builtin::BI__builtin___NSStringMakeConstantString)
return Success(E);
return ExprEvaluatorBaseTy::VisitCallExpr(E);
}
//===----------------------------------------------------------------------===//
// Vector Evaluation
//===----------------------------------------------------------------------===//
namespace {
class VectorExprEvaluator
: public ExprEvaluatorBase<VectorExprEvaluator, APValue> {
APValue GetZeroVector(QualType VecType);
public:
VectorExprEvaluator(EvalInfo &info) : ExprEvaluatorBaseTy(info) {}
APValue Success(const APValue &V, const Expr *E) { return V; }
APValue Error(const Expr *E) { return APValue(); }
APValue ValueInitialization(const Expr *E)
{ return GetZeroVector(E->getType()); }
APValue VisitUnaryReal(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
APValue VisitCastExpr(const CastExpr* E);
APValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
APValue VisitInitListExpr(const InitListExpr *E);
APValue VisitUnaryImag(const UnaryOperator *E);
// FIXME: Missing: unary -, unary ~, binary add/sub/mul/div,
// binary comparisons, binary and/or/xor,
// shufflevector, ExtVectorElementExpr
// (Note that these require implementing conversions
// between vector types.)
};
} // end anonymous namespace
static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
if (!E->getType()->isVectorType())
return false;
Result = VectorExprEvaluator(Info).Visit(E);
return !Result.isUninit();
}
APValue VectorExprEvaluator::VisitCastExpr(const CastExpr* E) {
const VectorType *VTy = E->getType()->getAs<VectorType>();
QualType EltTy = VTy->getElementType();
unsigned NElts = VTy->getNumElements();
unsigned EltWidth = Info.Ctx.getTypeSize(EltTy);
const Expr* SE = E->getSubExpr();
QualType SETy = SE->getType();
switch (E->getCastKind()) {
case CK_VectorSplat: {
APValue Result = APValue();
if (SETy->isIntegerType()) {
APSInt IntResult;
if (!EvaluateInteger(SE, IntResult, Info))
return APValue();
Result = APValue(IntResult);
} else if (SETy->isRealFloatingType()) {
APFloat F(0.0);
if (!EvaluateFloat(SE, F, Info))
return APValue();
Result = APValue(F);
} else {
return APValue();
}
// Splat and create vector APValue.
SmallVector<APValue, 4> Elts(NElts, Result);
return APValue(&Elts[0], Elts.size());
}
case CK_BitCast: {
if (SETy->isVectorType())
return Visit(SE);
if (!SETy->isIntegerType())
return APValue();
APSInt Init;
if (!EvaluateInteger(SE, Init, Info))
return APValue();
assert((EltTy->isIntegerType() || EltTy->isRealFloatingType()) &&
"Vectors must be composed of ints or floats");
SmallVector<APValue, 4> Elts;
for (unsigned i = 0; i != NElts; ++i) {
APSInt Tmp = Init.extOrTrunc(EltWidth);
if (EltTy->isIntegerType())
Elts.push_back(APValue(Tmp));
else
Elts.push_back(APValue(APFloat(Tmp)));
Init >>= EltWidth;
}
return APValue(&Elts[0], Elts.size());
}
case CK_LValueToRValue:
case CK_NoOp:
return Visit(SE);
default:
return APValue();
}
}
APValue
VectorExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
return this->Visit(E->getInitializer());
}
APValue
VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
const VectorType *VT = E->getType()->getAs<VectorType>();
unsigned NumInits = E->getNumInits();
unsigned NumElements = VT->getNumElements();
QualType EltTy = VT->getElementType();
SmallVector<APValue, 4> Elements;
// If a vector is initialized with a single element, that value
// becomes every element of the vector, not just the first.
// This is the behavior described in the IBM AltiVec documentation.
if (NumInits == 1) {
// Handle the case where the vector is initialized by a another
// vector (OpenCL 6.1.6).
if (E->getInit(0)->getType()->isVectorType())
return this->Visit(const_cast<Expr*>(E->getInit(0)));
APValue InitValue;
if (EltTy->isIntegerType()) {
llvm::APSInt sInt(32);
if (!EvaluateInteger(E->getInit(0), sInt, Info))
return APValue();
InitValue = APValue(sInt);
} else {
llvm::APFloat f(0.0);
if (!EvaluateFloat(E->getInit(0), f, Info))
return APValue();
InitValue = APValue(f);
}
for (unsigned i = 0; i < NumElements; i++) {
Elements.push_back(InitValue);
}
} else {
for (unsigned i = 0; i < NumElements; i++) {
if (EltTy->isIntegerType()) {
llvm::APSInt sInt(32);
if (i < NumInits) {
if (!EvaluateInteger(E->getInit(i), sInt, Info))
return APValue();
} else {
sInt = Info.Ctx.MakeIntValue(0, EltTy);
}
Elements.push_back(APValue(sInt));
} else {
llvm::APFloat f(0.0);
if (i < NumInits) {
if (!EvaluateFloat(E->getInit(i), f, Info))
return APValue();
} else {
f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
}
Elements.push_back(APValue(f));
}
}
}
return APValue(&Elements[0], Elements.size());
}
APValue
VectorExprEvaluator::GetZeroVector(QualType T) {
const VectorType *VT = T->getAs<VectorType>();
QualType EltTy = VT->getElementType();
APValue ZeroElement;
if (EltTy->isIntegerType())
ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
else
ZeroElement =
APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
return APValue(&Elements[0], Elements.size());
}
APValue VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
APValue Scratch;
if (!Evaluate(Scratch, Info, E->getSubExpr()))
Info.EvalStatus.HasSideEffects = true;
return GetZeroVector(E->getType());
}
//===----------------------------------------------------------------------===//
// Integer Evaluation
//===----------------------------------------------------------------------===//
namespace {
class IntExprEvaluator
: public ExprEvaluatorBase<IntExprEvaluator, bool> {
APValue &Result;
public:
IntExprEvaluator(EvalInfo &info, APValue &result)
: ExprEvaluatorBaseTy(info), Result(result) {}
bool Success(const llvm::APSInt &SI, const Expr *E) {
assert(E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.");
assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
"Invalid evaluation result.");
assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.");
Result = APValue(SI);
return true;
}
bool Success(const llvm::APInt &I, const Expr *E) {
assert(E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.");
assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.");
Result = APValue(APSInt(I));
Result.getInt().setIsUnsigned(
E->getType()->isUnsignedIntegerOrEnumerationType());
return true;
}
bool Success(uint64_t Value, const Expr *E) {
assert(E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.");
Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
return true;
}
bool Success(CharUnits Size, const Expr *E) {
return Success(Size.getQuantity(), E);
}
bool Error(SourceLocation L, diag::kind D, const Expr *E) {
// Take the first error.
if (Info.EvalStatus.Diag == 0) {
Info.EvalStatus.DiagLoc = L;
Info.EvalStatus.Diag = D;
Info.EvalStatus.DiagExpr = E;
}
return false;
}
bool Success(const APValue &V, const Expr *E) {
return Success(V.getInt(), E);
}
bool Error(const Expr *E) {
return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
bool ValueInitialization(const Expr *E) { return Success(0, E); }
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//
bool VisitIntegerLiteral(const IntegerLiteral *E) {
return Success(E->getValue(), E);
}
bool VisitCharacterLiteral(const CharacterLiteral *E) {
return Success(E->getValue(), E);
}
bool CheckReferencedDecl(const Expr *E, const Decl *D);
bool VisitDeclRefExpr(const DeclRefExpr *E) {
if (CheckReferencedDecl(E, E->getDecl()))
return true;
return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
}
bool VisitMemberExpr(const MemberExpr *E) {
if (CheckReferencedDecl(E, E->getMemberDecl())) {
// Conservatively assume a MemberExpr will have side-effects
Info.EvalStatus.HasSideEffects = true;
return true;
}
return ExprEvaluatorBaseTy::VisitMemberExpr(E);
}
bool VisitCallExpr(const CallExpr *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitOffsetOfExpr(const OffsetOfExpr *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitCastExpr(const CastExpr* E);
bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
return Success(E->getValue(), E);
}
// Note, GNU defines __null as an integer, not a pointer.
bool VisitGNUNullExpr(const GNUNullExpr *E) {
return ValueInitialization(E);
}
bool VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) {
return Success(E->getValue(), E);
}
bool VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr *E) {
return Success(E->getValue(), E);
}
bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
return Success(E->getValue(), E);
}
bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
return Success(E->getValue(), E);
}
bool VisitUnaryReal(const UnaryOperator *E);
bool VisitUnaryImag(const UnaryOperator *E);
bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
private:
CharUnits GetAlignOfExpr(const Expr *E);
CharUnits GetAlignOfType(QualType T);
static QualType GetObjectType(const Expr *E);
bool TryEvaluateBuiltinObjectSize(const CallExpr *E);
// FIXME: Missing: array subscript of vector, member of vector
};
} // end anonymous namespace
static bool EvaluateIntegerOrLValue(const Expr* E, APValue &Result, EvalInfo &Info) {
assert(E->getType()->isIntegralOrEnumerationType());
return IntExprEvaluator(Info, Result).Visit(E);
}
static bool EvaluateInteger(const Expr* E, APSInt &Result, EvalInfo &Info) {
assert(E->getType()->isIntegralOrEnumerationType());
APValue Val;
if (!EvaluateIntegerOrLValue(E, Val, Info) || !Val.isInt())
return false;
Result = Val.getInt();
return true;
}
bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
// Enums are integer constant exprs.
if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
// Check for signedness/width mismatches between E type and ECD value.
bool SameSign = (ECD->getInitVal().isSigned()
== E->getType()->isSignedIntegerOrEnumerationType());
bool SameWidth = (ECD->getInitVal().getBitWidth()
== Info.Ctx.getIntWidth(E->getType()));
if (SameSign && SameWidth)
return Success(ECD->getInitVal(), E);
else {
// Get rid of mismatch (otherwise Success assertions will fail)
// by computing a new value matching the type of E.
llvm::APSInt Val = ECD->getInitVal();
if (!SameSign)
Val.setIsSigned(!ECD->getInitVal().isSigned());
if (!SameWidth)
Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
return Success(Val, E);
}
}
// In C++, const, non-volatile integers initialized with ICEs are ICEs.
// In C, they can also be folded, although they are not ICEs.
if (Info.Ctx.getCanonicalType(E->getType()).getCVRQualifiers()
== Qualifiers::Const) {
if (isa<ParmVarDecl>(D))
return false;
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (const Expr *Init = VD->getAnyInitializer()) {
if (APValue *V = VD->getEvaluatedValue()) {
if (V->isInt())
return Success(V->getInt(), E);
return false;
}
if (VD->isEvaluatingValue())
return false;
VD->setEvaluatingValue();
Expr::EvalResult EResult;
// FIXME: Produce a diagnostic if the initializer isn't a constant
// expression.
if (Init->Evaluate(EResult, Info.Ctx) && !EResult.HasSideEffects &&
EResult.Val.isInt()) {
// Cache the evaluated value in the variable declaration.
Result = EResult.Val;
VD->setEvaluatedValue(Result);
return true;
}
VD->setEvaluatedValue(APValue());
}
}
}
// Otherwise, random variable references are not constants.
return false;
}
/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
/// as GCC.
static int EvaluateBuiltinClassifyType(const CallExpr *E) {
// The following enum mimics the values returned by GCC.
// FIXME: Does GCC differ between lvalue and rvalue references here?
enum gcc_type_class {
no_type_class = -1,
void_type_class, integer_type_class, char_type_class,
enumeral_type_class, boolean_type_class,
pointer_type_class, reference_type_class, offset_type_class,
real_type_class, complex_type_class,
function_type_class, method_type_class,
record_type_class, union_type_class,
array_type_class, string_type_class,
lang_type_class
};
// If no argument was supplied, default to "no_type_class". This isn't
// ideal, however it is what gcc does.
if (E->getNumArgs() == 0)
return no_type_class;
QualType ArgTy = E->getArg(0)->getType();
if (ArgTy->isVoidType())
return void_type_class;
else if (ArgTy->isEnumeralType())
return enumeral_type_class;
else if (ArgTy->isBooleanType())
return boolean_type_class;
else if (ArgTy->isCharType())
return string_type_class; // gcc doesn't appear to use char_type_class
else if (ArgTy->isIntegerType())
return integer_type_class;
else if (ArgTy->isPointerType())
return pointer_type_class;
else if (ArgTy->isReferenceType())
return reference_type_class;
else if (ArgTy->isRealType())
return real_type_class;
else if (ArgTy->isComplexType())
return complex_type_class;
else if (ArgTy->isFunctionType())
return function_type_class;
else if (ArgTy->isStructureOrClassType())
return record_type_class;
else if (ArgTy->isUnionType())
return union_type_class;
else if (ArgTy->isArrayType())
return array_type_class;
else if (ArgTy->isUnionType())
return union_type_class;
else // FIXME: offset_type_class, method_type_class, & lang_type_class?
llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
return -1;
}
/// Retrieves the "underlying object type" of the given expression,
/// as used by __builtin_object_size.
QualType IntExprEvaluator::GetObjectType(const Expr *E) {
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
return VD->getType();
} else if (isa<CompoundLiteralExpr>(E)) {
return E->getType();
}
return QualType();
}
bool IntExprEvaluator::TryEvaluateBuiltinObjectSize(const CallExpr *E) {
// TODO: Perhaps we should let LLVM lower this?
LValue Base;
if (!EvaluatePointer(E->getArg(0), Base, Info))
return false;
// If we can prove the base is null, lower to zero now.
const Expr *LVBase = Base.getLValueBase();
if (!LVBase) return Success(0, E);
QualType T = GetObjectType(LVBase);
if (T.isNull() ||
T->isIncompleteType() ||
T->isFunctionType() ||
T->isVariablyModifiedType() ||
T->isDependentType())
return false;
CharUnits Size = Info.Ctx.getTypeSizeInChars(T);
CharUnits Offset = Base.getLValueOffset();
if (!Offset.isNegative() && Offset <= Size)
Size -= Offset;
else
Size = CharUnits::Zero();
return Success(Size, E);
}
bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
switch (E->isBuiltinCall(Info.Ctx)) {
default:
return ExprEvaluatorBaseTy::VisitCallExpr(E);
case Builtin::BI__builtin_object_size: {
if (TryEvaluateBuiltinObjectSize(E))
return true;
// If evaluating the argument has side-effects we can't determine
// the size of the object and lower it to unknown now.
if (E->getArg(0)->HasSideEffects(Info.Ctx)) {
if (E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue() <= 1)
return Success(-1ULL, E);
return Success(0, E);
}
return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
case Builtin::BI__builtin_classify_type:
return Success(EvaluateBuiltinClassifyType(E), E);
case Builtin::BI__builtin_constant_p:
// __builtin_constant_p always has one operand: it returns true if that
// operand can be folded, false otherwise.
return Success(E->getArg(0)->isEvaluatable(Info.Ctx), E);
case Builtin::BI__builtin_eh_return_data_regno: {
int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
return Success(Operand, E);
}
case Builtin::BI__builtin_expect:
return Visit(E->getArg(0));
case Builtin::BIstrlen:
case Builtin::BI__builtin_strlen:
// As an extension, we support strlen() and __builtin_strlen() as constant
// expressions when the argument is a string literal.
if (const StringLiteral *S
= dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenImpCasts())) {
// The string literal may have embedded null characters. Find the first
// one and truncate there.
StringRef Str = S->getString();
StringRef::size_type Pos = Str.find(0);
if (Pos != StringRef::npos)
Str = Str.substr(0, Pos);
return Success(Str.size(), E);
}
return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
}
bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->getOpcode() == BO_Comma) {
if (!Visit(E->getRHS()))
return false;
// If we can't evaluate the LHS, it might have side effects;
// conservatively mark it.
APValue Scratch;
if (!Evaluate(Scratch, Info, E->getLHS()))
Info.EvalStatus.HasSideEffects = true;
return true;
}
if (E->isLogicalOp()) {
// These need to be handled specially because the operands aren't
// necessarily integral
bool lhsResult, rhsResult;
if (HandleConversionToBool(E->getLHS(), lhsResult, Info)) {
// We were able to evaluate the LHS, see if we can get away with not
// evaluating the RHS: 0 && X -> 0, 1 || X -> 1
if (lhsResult == (E->getOpcode() == BO_LOr))
return Success(lhsResult, E);
if (HandleConversionToBool(E->getRHS(), rhsResult, Info)) {
if (E->getOpcode() == BO_LOr)
return Success(lhsResult || rhsResult, E);
else
return Success(lhsResult && rhsResult, E);
}
} else {
if (HandleConversionToBool(E->getRHS(), rhsResult, Info)) {
// We can't evaluate the LHS; however, sometimes the result
// is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
if (rhsResult == (E->getOpcode() == BO_LOr) ||
!rhsResult == (E->getOpcode() == BO_LAnd)) {
// Since we weren't able to evaluate the left hand side, it
// must have had side effects.
Info.EvalStatus.HasSideEffects = true;
return Success(rhsResult, E);
}
}
}
return false;
}
QualType LHSTy = E->getLHS()->getType();
QualType RHSTy = E->getRHS()->getType();
if (LHSTy->isAnyComplexType()) {
assert(RHSTy->isAnyComplexType() && "Invalid comparison");
ComplexValue LHS, RHS;
if (!EvaluateComplex(E->getLHS(), LHS, Info))
return false;
if (!EvaluateComplex(E->getRHS(), RHS, Info))
return false;
if (LHS.isComplexFloat()) {
APFloat::cmpResult CR_r =
LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
APFloat::cmpResult CR_i =
LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
if (E->getOpcode() == BO_EQ)
return Success((CR_r == APFloat::cmpEqual &&
CR_i == APFloat::cmpEqual), E);
else {
assert(E->getOpcode() == BO_NE &&
"Invalid complex comparison.");
return Success(((CR_r == APFloat::cmpGreaterThan ||
CR_r == APFloat::cmpLessThan ||
CR_r == APFloat::cmpUnordered) ||
(CR_i == APFloat::cmpGreaterThan ||
CR_i == APFloat::cmpLessThan ||
CR_i == APFloat::cmpUnordered)), E);
}
} else {
if (E->getOpcode() == BO_EQ)
return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
LHS.getComplexIntImag() == RHS.getComplexIntImag()), E);
else {
assert(E->getOpcode() == BO_NE &&
"Invalid compex comparison.");
return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() ||
LHS.getComplexIntImag() != RHS.getComplexIntImag()), E);
}
}
}
if (LHSTy->isRealFloatingType() &&
RHSTy->isRealFloatingType()) {
APFloat RHS(0.0), LHS(0.0);
if (!EvaluateFloat(E->getRHS(), RHS, Info))
return false;
if (!EvaluateFloat(E->getLHS(), LHS, Info))
return false;
APFloat::cmpResult CR = LHS.compare(RHS);
switch (E->getOpcode()) {
default:
llvm_unreachable("Invalid binary operator!");
case BO_LT:
return Success(CR == APFloat::cmpLessThan, E);
case BO_GT:
return Success(CR == APFloat::cmpGreaterThan, E);
case BO_LE:
return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E);
case BO_GE:
return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual,
E);
case BO_EQ:
return Success(CR == APFloat::cmpEqual, E);
case BO_NE:
return Success(CR == APFloat::cmpGreaterThan
|| CR == APFloat::cmpLessThan
|| CR == APFloat::cmpUnordered, E);
}
}
if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
if (E->getOpcode() == BO_Sub || E->isEqualityOp()) {
LValue LHSValue;
if (!EvaluatePointer(E->getLHS(), LHSValue, Info))
return false;
LValue RHSValue;
if (!EvaluatePointer(E->getRHS(), RHSValue, Info))
return false;
// Reject any bases from the normal codepath; we special-case comparisons
// to null.
if (LHSValue.getLValueBase()) {
if (!E->isEqualityOp())
return false;
if (RHSValue.getLValueBase() || !RHSValue.getLValueOffset().isZero())
return false;
bool bres;
if (!EvalPointerValueAsBool(LHSValue, bres))
return false;
return Success(bres ^ (E->getOpcode() == BO_EQ), E);
} else if (RHSValue.getLValueBase()) {
if (!E->isEqualityOp())
return false;
if (LHSValue.getLValueBase() || !LHSValue.getLValueOffset().isZero())
return false;
bool bres;
if (!EvalPointerValueAsBool(RHSValue, bres))
return false;
return Success(bres ^ (E->getOpcode() == BO_EQ), E);
}
if (E->getOpcode() == BO_Sub) {
QualType Type = E->getLHS()->getType();
QualType ElementType = Type->getAs<PointerType>()->getPointeeType();
CharUnits ElementSize = CharUnits::One();
if (!ElementType->isVoidType() && !ElementType->isFunctionType())
ElementSize = Info.Ctx.getTypeSizeInChars(ElementType);
CharUnits Diff = LHSValue.getLValueOffset() -
RHSValue.getLValueOffset();
return Success(Diff / ElementSize, E);
}
bool Result;
if (E->getOpcode() == BO_EQ) {
Result = LHSValue.getLValueOffset() == RHSValue.getLValueOffset();
} else {
Result = LHSValue.getLValueOffset() != RHSValue.getLValueOffset();
}
return Success(Result, E);
}
}
if (!LHSTy->isIntegralOrEnumerationType() ||
!RHSTy->isIntegralOrEnumerationType()) {
// We can't continue from here for non-integral types, and they
// could potentially confuse the following operations.
return false;
}
// The LHS of a constant expr is always evaluated and needed.
if (!Visit(E->getLHS()))
return false; // error in subexpression.
APValue RHSVal;
if (!EvaluateIntegerOrLValue(E->getRHS(), RHSVal, Info))
return false;
// Handle cases like (unsigned long)&a + 4.
if (E->isAdditiveOp() && Result.isLValue() && RHSVal.isInt()) {
CharUnits Offset = Result.getLValueOffset();
CharUnits AdditionalOffset = CharUnits::fromQuantity(
RHSVal.getInt().getZExtValue());
if (E->getOpcode() == BO_Add)
Offset += AdditionalOffset;
else
Offset -= AdditionalOffset;
Result = APValue(Result.getLValueBase(), Offset);
return true;
}
// Handle cases like 4 + (unsigned long)&a
if (E->getOpcode() == BO_Add &&
RHSVal.isLValue() && Result.isInt()) {
CharUnits Offset = RHSVal.getLValueOffset();
Offset += CharUnits::fromQuantity(Result.getInt().getZExtValue());
Result = APValue(RHSVal.getLValueBase(), Offset);
return true;
}
// All the following cases expect both operands to be an integer
if (!Result.isInt() || !RHSVal.isInt())
return false;
APSInt& RHS = RHSVal.getInt();
switch (E->getOpcode()) {
default:
return Error(E->getOperatorLoc(), diag::note_invalid_subexpr_in_ice, E);
case BO_Mul: return Success(Result.getInt() * RHS, E);
case BO_Add: return Success(Result.getInt() + RHS, E);
case BO_Sub: return Success(Result.getInt() - RHS, E);
case BO_And: return Success(Result.getInt() & RHS, E);
case BO_Xor: return Success(Result.getInt() ^ RHS, E);
case BO_Or: return Success(Result.getInt() | RHS, E);
case BO_Div:
if (RHS == 0)
return Error(E->getOperatorLoc(), diag::note_expr_divide_by_zero, E);
return Success(Result.getInt() / RHS, E);
case BO_Rem:
if (RHS == 0)
return Error(E->getOperatorLoc(), diag::note_expr_divide_by_zero, E);
return Success(Result.getInt() % RHS, E);
case BO_Shl: {
// During constant-folding, a negative shift is an opposite shift.
if (RHS.isSigned() && RHS.isNegative()) {
RHS = -RHS;
goto shift_right;
}
shift_left:
unsigned SA
= (unsigned) RHS.getLimitedValue(Result.getInt().getBitWidth()-1);
return Success(Result.getInt() << SA, E);
}
case BO_Shr: {
// During constant-folding, a negative shift is an opposite shift.
if (RHS.isSigned() && RHS.isNegative()) {
RHS = -RHS;
goto shift_left;
}
shift_right:
unsigned SA =
(unsigned) RHS.getLimitedValue(Result.getInt().getBitWidth()-1);
return Success(Result.getInt() >> SA, E);
}
case BO_LT: return Success(Result.getInt() < RHS, E);
case BO_GT: return Success(Result.getInt() > RHS, E);
case BO_LE: return Success(Result.getInt() <= RHS, E);
case BO_GE: return Success(Result.getInt() >= RHS, E);
case BO_EQ: return Success(Result.getInt() == RHS, E);
case BO_NE: return Success(Result.getInt() != RHS, E);
}
}
CharUnits IntExprEvaluator::GetAlignOfType(QualType T) {
// C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
// the result is the size of the referenced type."
// C++ [expr.alignof]p3: "When alignof is applied to a reference type, the
// result shall be the alignment of the referenced type."
if (const ReferenceType *Ref = T->getAs<ReferenceType>())
T = Ref->getPointeeType();
// __alignof is defined to return the preferred alignment.
return Info.Ctx.toCharUnitsFromBits(
Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
}
CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) {
E = E->IgnoreParens();
// alignof decl is always accepted, even if it doesn't make sense: we default
// to 1 in those cases.
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
return Info.Ctx.getDeclAlign(DRE->getDecl(),
/*RefAsPointee*/true);
if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
/*RefAsPointee*/true);
return GetAlignOfType(E->getType());
}
/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
/// a result as the expression's type.
bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
const UnaryExprOrTypeTraitExpr *E) {
switch(E->getKind()) {
case UETT_AlignOf: {
if (E->isArgumentType())
return Success(GetAlignOfType(E->getArgumentType()), E);
else
return Success(GetAlignOfExpr(E->getArgumentExpr()), E);
}
case UETT_VecStep: {
QualType Ty = E->getTypeOfArgument();
if (Ty->isVectorType()) {
unsigned n = Ty->getAs<VectorType>()->getNumElements();
// The vec_step built-in functions that take a 3-component
// vector return 4. (OpenCL 1.1 spec 6.11.12)
if (n == 3)
n = 4;
return Success(n, E);
} else
return Success(1, E);
}
case UETT_SizeOf: {
QualType SrcTy = E->getTypeOfArgument();
// C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
// the result is the size of the referenced type."
// C++ [expr.alignof]p3: "When alignof is applied to a reference type, the
// result shall be the alignment of the referenced type."
if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
SrcTy = Ref->getPointeeType();
// sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
// extension.
if (SrcTy->isVoidType() || SrcTy->isFunctionType())
return Success(1, E);
// sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
if (!SrcTy->isConstantSizeType())
return false;
// Get information about the size.
return Success(Info.Ctx.getTypeSizeInChars(SrcTy), E);
}
}
llvm_unreachable("unknown expr/type trait");
return false;
}
bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
CharUnits Result;
unsigned n = OOE->getNumComponents();
if (n == 0)
return false;
QualType CurrentType = OOE->getTypeSourceInfo()->getType();
for (unsigned i = 0; i != n; ++i) {
OffsetOfExpr::OffsetOfNode ON = OOE->getComponent(i);
switch (ON.getKind()) {
case OffsetOfExpr::OffsetOfNode::Array: {
const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
APSInt IdxResult;
if (!EvaluateInteger(Idx, IdxResult, Info))
return false;
const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
if (!AT)
return false;
CurrentType = AT->getElementType();
CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
Result += IdxResult.getSExtValue() * ElementSize;
break;
}
case OffsetOfExpr::OffsetOfNode::Field: {
FieldDecl *MemberDecl = ON.getField();
const RecordType *RT = CurrentType->getAs<RecordType>();
if (!RT)
return false;
RecordDecl *RD = RT->getDecl();
const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
unsigned i = MemberDecl->getFieldIndex();
assert(i < RL.getFieldCount() && "offsetof field in wrong type");
Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
CurrentType = MemberDecl->getType().getNonReferenceType();
break;
}
case OffsetOfExpr::OffsetOfNode::Identifier:
llvm_unreachable("dependent __builtin_offsetof");
return false;
case OffsetOfExpr::OffsetOfNode::Base: {
CXXBaseSpecifier *BaseSpec = ON.getBase();
if (BaseSpec->isVirtual())
return false;
// Find the layout of the class whose base we are looking into.
const RecordType *RT = CurrentType->getAs<RecordType>();
if (!RT)
return false;
RecordDecl *RD = RT->getDecl();
const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
// Find the base class itself.
CurrentType = BaseSpec->getType();
const RecordType *BaseRT = CurrentType->getAs<RecordType>();
if (!BaseRT)
return false;
// Add the offset to the base.
Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
break;
}
}
}
return Success(Result, OOE);
}
bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
if (E->getOpcode() == UO_LNot) {
// LNot's operand isn't necessarily an integer, so we handle it specially.
bool bres;
if (!HandleConversionToBool(E->getSubExpr(), bres, Info))
return false;
return Success(!bres, E);
}
// Only handle integral operations...
if (!E->getSubExpr()->getType()->isIntegralOrEnumerationType())
return false;
// Get the operand value into 'Result'.
if (!Visit(E->getSubExpr()))
return false;
switch (E->getOpcode()) {
default:
// Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
// See C99 6.6p3.
return Error(E->getOperatorLoc(), diag::note_invalid_subexpr_in_ice, E);
case UO_Extension:
// FIXME: Should extension allow i-c-e extension expressions in its scope?
// If so, we could clear the diagnostic ID.
return true;
case UO_Plus:
// The result is always just the subexpr.
return true;
case UO_Minus:
if (!Result.isInt()) return false;
return Success(-Result.getInt(), E);
case UO_Not:
if (!Result.isInt()) return false;
return Success(~Result.getInt(), E);
}
}
/// HandleCast - This is used to evaluate implicit or explicit casts where the
/// result type is integer.
bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
const Expr *SubExpr = E->getSubExpr();
QualType DestType = E->getType();
QualType SrcType = SubExpr->getType();
switch (E->getCastKind()) {
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_ToUnion:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_NullToPointer:
case CK_NullToMemberPointer:
case CK_BaseToDerivedMemberPointer:
case CK_DerivedToBaseMemberPointer:
case CK_ConstructorConversion:
case CK_IntegralToPointer:
case CK_ToVoid:
case CK_VectorSplat:
case CK_IntegralToFloating:
case CK_FloatingCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_ObjCObjectLValueCast:
case CK_FloatingRealToComplex:
case CK_FloatingComplexToReal:
case CK_FloatingComplexCast:
case CK_FloatingComplexToIntegralComplex:
case CK_IntegralRealToComplex:
case CK_IntegralComplexCast:
case CK_IntegralComplexToFloatingComplex:
llvm_unreachable("invalid cast kind for integral value");
case CK_BitCast:
case CK_Dependent:
case CK_GetObjCProperty:
case CK_LValueBitCast:
case CK_UserDefinedConversion:
case CK_ARCProduceObject:
case CK_ARCConsumeObject:
case CK_ARCReclaimReturnedObject:
case CK_ARCExtendBlockObject:
return false;
case CK_LValueToRValue:
case CK_NoOp:
return Visit(E->getSubExpr());
case CK_MemberPointerToBoolean:
case CK_PointerToBoolean:
case CK_IntegralToBoolean:
case CK_FloatingToBoolean:
case CK_FloatingComplexToBoolean:
case CK_IntegralComplexToBoolean: {
bool BoolResult;
if (!HandleConversionToBool(SubExpr, BoolResult, Info))
return false;
return Success(BoolResult, E);
}
case CK_IntegralCast: {
if (!Visit(SubExpr))
return false;
if (!Result.isInt()) {
// Only allow casts of lvalues if they are lossless.
return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
}
return Success(HandleIntToIntCast(DestType, SrcType,
Result.getInt(), Info.Ctx), E);
}
case CK_PointerToIntegral: {
LValue LV;
if (!EvaluatePointer(SubExpr, LV, Info))
return false;
if (LV.getLValueBase()) {
// Only allow based lvalue casts if they are lossless.
if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
return false;
LV.moveInto(Result);
return true;
}
APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset().getQuantity(),
SrcType);
return Success(HandleIntToIntCast(DestType, SrcType, AsInt, Info.Ctx), E);
}
case CK_IntegralComplexToReal: {
ComplexValue C;
if (!EvaluateComplex(SubExpr, C, Info))
return false;
return Success(C.getComplexIntReal(), E);
}
case CK_FloatingToIntegral: {
APFloat F(0.0);
if (!EvaluateFloat(SubExpr, F, Info))
return false;
return Success(HandleFloatToIntCast(DestType, SrcType, F, Info.Ctx), E);
}
}
llvm_unreachable("unknown cast resulting in integral value");
return false;
}
bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isAnyComplexType()) {
ComplexValue LV;
if (!EvaluateComplex(E->getSubExpr(), LV, Info) || !LV.isComplexInt())
return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E);
return Success(LV.getComplexIntReal(), E);
}
return Visit(E->getSubExpr());
}
bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isComplexIntegerType()) {
ComplexValue LV;
if (!EvaluateComplex(E->getSubExpr(), LV, Info) || !LV.isComplexInt())
return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E);
return Success(LV.getComplexIntImag(), E);
}
APValue Scratch;
if (!Evaluate(Scratch, Info, E->getSubExpr()))
Info.EvalStatus.HasSideEffects = true;
return Success(0, E);
}
bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
return Success(E->getPackLength(), E);
}
bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
return Success(E->getValue(), E);
}
//===----------------------------------------------------------------------===//
// Float Evaluation
//===----------------------------------------------------------------------===//
namespace {
class FloatExprEvaluator
: public ExprEvaluatorBase<FloatExprEvaluator, bool> {
APFloat &Result;
public:
FloatExprEvaluator(EvalInfo &info, APFloat &result)
: ExprEvaluatorBaseTy(info), Result(result) {}
bool Success(const APValue &V, const Expr *e) {
Result = V.getFloat();
return true;
}
bool Error(const Stmt *S) {
return false;
}
bool ValueInitialization(const Expr *E) {
Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
return true;
}
bool VisitCallExpr(const CallExpr *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitFloatingLiteral(const FloatingLiteral *E);
bool VisitCastExpr(const CastExpr *E);
bool VisitUnaryReal(const UnaryOperator *E);
bool VisitUnaryImag(const UnaryOperator *E);
bool VisitDeclRefExpr(const DeclRefExpr *E);
// FIXME: Missing: array subscript of vector, member of vector,
// ImplicitValueInitExpr
};
} // end anonymous namespace
static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
assert(E->getType()->isRealFloatingType());
return FloatExprEvaluator(Info, Result).Visit(E);
}
static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
QualType ResultTy,
const Expr *Arg,
bool SNaN,
llvm::APFloat &Result) {
const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
if (!S) return false;
const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
llvm::APInt fill;
// Treat empty strings as if they were zero.
if (S->getString().empty())
fill = llvm::APInt(32, 0);
else if (S->getString().getAsInteger(0, fill))
return false;
if (SNaN)
Result = llvm::APFloat::getSNaN(Sem, false, &fill);
else
Result = llvm::APFloat::getQNaN(Sem, false, &fill);
return true;
}
bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
switch (E->isBuiltinCall(Info.Ctx)) {
default:
return ExprEvaluatorBaseTy::VisitCallExpr(E);
case Builtin::BI__builtin_huge_val:
case Builtin::BI__builtin_huge_valf:
case Builtin::BI__builtin_huge_vall:
case Builtin::BI__builtin_inf:
case Builtin::BI__builtin_inff:
case Builtin::BI__builtin_infl: {
const llvm::fltSemantics &Sem =
Info.Ctx.getFloatTypeSemantics(E->getType());
Result = llvm::APFloat::getInf(Sem);
return true;
}
case Builtin::BI__builtin_nans:
case Builtin::BI__builtin_nansf:
case Builtin::BI__builtin_nansl:
return TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
true, Result);
case Builtin::BI__builtin_nan:
case Builtin::BI__builtin_nanf:
case Builtin::BI__builtin_nanl:
// If this is __builtin_nan() turn this into a nan, otherwise we
// can't constant fold it.
return TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
false, Result);
case Builtin::BI__builtin_fabs:
case Builtin::BI__builtin_fabsf:
case Builtin::BI__builtin_fabsl:
if (!EvaluateFloat(E->getArg(0), Result, Info))
return false;
if (Result.isNegative())
Result.changeSign();
return true;
case Builtin::BI__builtin_copysign:
case Builtin::BI__builtin_copysignf:
case Builtin::BI__builtin_copysignl: {
APFloat RHS(0.);
if (!EvaluateFloat(E->getArg(0), Result, Info) ||
!EvaluateFloat(E->getArg(1), RHS, Info))
return false;
Result.copySign(RHS);
return true;
}
}
}
bool FloatExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
if (ExprEvaluatorBaseTy::VisitDeclRefExpr(E))
return true;
const Decl *D = E->getDecl();
if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D)) return false;
const VarDecl *VD = cast<VarDecl>(D);
// Require the qualifiers to be const and not volatile.
CanQualType T = Info.Ctx.getCanonicalType(E->getType());
if (!T.isConstQualified() || T.isVolatileQualified())
return false;
const Expr *Init = VD->getAnyInitializer();
if (!Init) return false;
if (APValue *V = VD->getEvaluatedValue()) {
if (V->isFloat()) {
Result = V->getFloat();
return true;
}
return false;
}
if (VD->isEvaluatingValue())
return false;
VD->setEvaluatingValue();
Expr::EvalResult InitResult;
if (Init->Evaluate(InitResult, Info.Ctx) && !InitResult.HasSideEffects &&
InitResult.Val.isFloat()) {
// Cache the evaluated value in the variable declaration.
Result = InitResult.Val.getFloat();
VD->setEvaluatedValue(InitResult.Val);
return true;
}
VD->setEvaluatedValue(APValue());
return false;
}
bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isAnyComplexType()) {
ComplexValue CV;
if (!EvaluateComplex(E->getSubExpr(), CV, Info))
return false;
Result = CV.FloatReal;
return true;
}
return Visit(E->getSubExpr());
}
bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isAnyComplexType()) {
ComplexValue CV;
if (!EvaluateComplex(E->getSubExpr(), CV, Info))
return false;
Result = CV.FloatImag;
return true;
}
APValue Scratch;
if (!Evaluate(Scratch, Info, E->getSubExpr()))
Info.EvalStatus.HasSideEffects = true;
const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
Result = llvm::APFloat::getZero(Sem);
return true;
}
bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
if (E->getOpcode() == UO_Deref)
return false;
if (!EvaluateFloat(E->getSubExpr(), Result, Info))
return false;
switch (E->getOpcode()) {
default: return false;
case UO_Plus:
return true;
case UO_Minus:
Result.changeSign();
return true;
}
}
bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->getOpcode() == BO_Comma) {
if (!EvaluateFloat(E->getRHS(), Result, Info))
return false;
// If we can't evaluate the LHS, it might have side effects;
// conservatively mark it.
APValue Scratch;
if (!Evaluate(Scratch, Info, E->getLHS()))
Info.EvalStatus.HasSideEffects = true;
return true;
}
// We can't evaluate pointer-to-member operations.
if (E->isPtrMemOp())
return false;
// FIXME: Diagnostics? I really don't understand how the warnings
// and errors are supposed to work.
APFloat RHS(0.0);
if (!EvaluateFloat(E->getLHS(), Result, Info))
return false;
if (!EvaluateFloat(E->getRHS(), RHS, Info))
return false;
switch (E->getOpcode()) {
default: return false;
case BO_Mul:
Result.multiply(RHS, APFloat::rmNearestTiesToEven);
return true;
case BO_Add:
Result.add(RHS, APFloat::rmNearestTiesToEven);
return true;
case BO_Sub:
Result.subtract(RHS, APFloat::rmNearestTiesToEven);
return true;
case BO_Div:
Result.divide(RHS, APFloat::rmNearestTiesToEven);
return true;
}
}
bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
Result = E->getValue();
return true;
}
bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
const Expr* SubExpr = E->getSubExpr();
switch (E->getCastKind()) {
default:
return false;
case CK_LValueToRValue:
case CK_NoOp:
return Visit(SubExpr);
case CK_IntegralToFloating: {
APSInt IntResult;
if (!EvaluateInteger(SubExpr, IntResult, Info))
return false;
Result = HandleIntToFloatCast(E->getType(), SubExpr->getType(),
IntResult, Info.Ctx);
return true;
}
case CK_FloatingCast: {
if (!Visit(SubExpr))
return false;
Result = HandleFloatToFloatCast(E->getType(), SubExpr->getType(),
Result, Info.Ctx);
return true;
}
case CK_FloatingComplexToReal: {
ComplexValue V;
if (!EvaluateComplex(SubExpr, V, Info))
return false;
Result = V.getComplexFloatReal();
return true;
}
}
return false;
}
//===----------------------------------------------------------------------===//
// Complex Evaluation (for float and integer)
//===----------------------------------------------------------------------===//
namespace {
class ComplexExprEvaluator
: public ExprEvaluatorBase<ComplexExprEvaluator, bool> {
ComplexValue &Result;
public:
ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
: ExprEvaluatorBaseTy(info), Result(Result) {}
bool Success(const APValue &V, const Expr *e) {
Result.setFrom(V);
return true;
}
bool Error(const Expr *E) {
return false;
}
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//
bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
bool VisitCastExpr(const CastExpr *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitUnaryOperator(const UnaryOperator *E);
// FIXME Missing: ImplicitValueInitExpr, InitListExpr
};
} // end anonymous namespace
static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
EvalInfo &Info) {
assert(E->getType()->isAnyComplexType());
return ComplexExprEvaluator(Info, Result).Visit(E);
}
bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
const Expr* SubExpr = E->getSubExpr();
if (SubExpr->getType()->isRealFloatingType()) {
Result.makeComplexFloat();
APFloat &Imag = Result.FloatImag;
if (!EvaluateFloat(SubExpr, Imag, Info))
return false;
Result.FloatReal = APFloat(Imag.getSemantics());
return true;
} else {
assert(SubExpr->getType()->isIntegerType() &&
"Unexpected imaginary literal.");
Result.makeComplexInt();
APSInt &Imag = Result.IntImag;
if (!EvaluateInteger(SubExpr, Imag, Info))
return false;
Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
return true;
}
}
bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
switch (E->getCastKind()) {
case CK_BitCast:
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_ToUnion:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_NullToPointer:
case CK_NullToMemberPointer:
case CK_BaseToDerivedMemberPointer:
case CK_DerivedToBaseMemberPointer:
case CK_MemberPointerToBoolean:
case CK_ConstructorConversion:
case CK_IntegralToPointer:
case CK_PointerToIntegral:
case CK_PointerToBoolean:
case CK_ToVoid:
case CK_VectorSplat:
case CK_IntegralCast:
case CK_IntegralToBoolean:
case CK_IntegralToFloating:
case CK_FloatingToIntegral:
case CK_FloatingToBoolean:
case CK_FloatingCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_ObjCObjectLValueCast:
case CK_FloatingComplexToReal:
case CK_FloatingComplexToBoolean:
case CK_IntegralComplexToReal:
case CK_IntegralComplexToBoolean:
case CK_ARCProduceObject:
case CK_ARCConsumeObject:
case CK_ARCReclaimReturnedObject:
case CK_ARCExtendBlockObject:
llvm_unreachable("invalid cast kind for complex value");
case CK_LValueToRValue:
case CK_NoOp:
return Visit(E->getSubExpr());
case CK_Dependent:
case CK_GetObjCProperty:
case CK_LValueBitCast:
case CK_UserDefinedConversion:
return false;
case CK_FloatingRealToComplex: {
APFloat &Real = Result.FloatReal;
if (!EvaluateFloat(E->getSubExpr(), Real, Info))
return false;
Result.makeComplexFloat();
Result.FloatImag = APFloat(Real.getSemantics());
return true;
}
case CK_FloatingComplexCast: {
if (!Visit(E->getSubExpr()))
return false;
QualType To = E->getType()->getAs<ComplexType>()->getElementType();
QualType From
= E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
Result.FloatReal
= HandleFloatToFloatCast(To, From, Result.FloatReal, Info.Ctx);
Result.FloatImag
= HandleFloatToFloatCast(To, From, Result.FloatImag, Info.Ctx);
return true;
}
case CK_FloatingComplexToIntegralComplex: {
if (!Visit(E->getSubExpr()))
return false;
QualType To = E->getType()->getAs<ComplexType>()->getElementType();
QualType From
= E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
Result.makeComplexInt();
Result.IntReal = HandleFloatToIntCast(To, From, Result.FloatReal, Info.Ctx);
Result.IntImag = HandleFloatToIntCast(To, From, Result.FloatImag, Info.Ctx);
return true;
}
case CK_IntegralRealToComplex: {
APSInt &Real = Result.IntReal;
if (!EvaluateInteger(E->getSubExpr(), Real, Info))
return false;
Result.makeComplexInt();
Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
return true;
}
case CK_IntegralComplexCast: {
if (!Visit(E->getSubExpr()))
return false;
QualType To = E->getType()->getAs<ComplexType>()->getElementType();
QualType From
= E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
Result.IntReal = HandleIntToIntCast(To, From, Result.IntReal, Info.Ctx);
Result.IntImag = HandleIntToIntCast(To, From, Result.IntImag, Info.Ctx);
return true;
}
case CK_IntegralComplexToFloatingComplex: {
if (!Visit(E->getSubExpr()))
return false;
QualType To = E->getType()->getAs<ComplexType>()->getElementType();
QualType From
= E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
Result.makeComplexFloat();
Result.FloatReal = HandleIntToFloatCast(To, From, Result.IntReal, Info.Ctx);
Result.FloatImag = HandleIntToFloatCast(To, From, Result.IntImag, Info.Ctx);
return true;
}
}
llvm_unreachable("unknown cast resulting in complex value");
return false;
}
bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->getOpcode() == BO_Comma) {
if (!Visit(E->getRHS()))
return false;
// If we can't evaluate the LHS, it might have side effects;
// conservatively mark it.
APValue Scratch;
if (!Evaluate(Scratch, Info, E->getLHS()))
Info.EvalStatus.HasSideEffects = true;
return true;
}
if (!Visit(E->getLHS()))
return false;
ComplexValue RHS;
if (!EvaluateComplex(E->getRHS(), RHS, Info))
return false;
assert(Result.isComplexFloat() == RHS.isComplexFloat() &&
"Invalid operands to binary operator.");
switch (E->getOpcode()) {
default: return false;
case BO_Add:
if (Result.isComplexFloat()) {
Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
APFloat::rmNearestTiesToEven);
Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
APFloat::rmNearestTiesToEven);
} else {
Result.getComplexIntReal() += RHS.getComplexIntReal();
Result.getComplexIntImag() += RHS.getComplexIntImag();
}
break;
case BO_Sub:
if (Result.isComplexFloat()) {
Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
APFloat::rmNearestTiesToEven);
Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
APFloat::rmNearestTiesToEven);
} else {
Result.getComplexIntReal() -= RHS.getComplexIntReal();
Result.getComplexIntImag() -= RHS.getComplexIntImag();
}
break;
case BO_Mul:
if (Result.isComplexFloat()) {
ComplexValue LHS = Result;
APFloat &LHS_r = LHS.getComplexFloatReal();
APFloat &LHS_i = LHS.getComplexFloatImag();
APFloat &RHS_r = RHS.getComplexFloatReal();
APFloat &RHS_i = RHS.getComplexFloatImag();
APFloat Tmp = LHS_r;
Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven);
Result.getComplexFloatReal() = Tmp;
Tmp = LHS_i;
Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
Result.getComplexFloatReal().subtract(Tmp, APFloat::rmNearestTiesToEven);
Tmp = LHS_r;
Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
Result.getComplexFloatImag() = Tmp;
Tmp = LHS_i;
Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven);
Result.getComplexFloatImag().add(Tmp, APFloat::rmNearestTiesToEven);
} else {
ComplexValue LHS = Result;
Result.getComplexIntReal() =
(LHS.getComplexIntReal() * RHS.getComplexIntReal() -
LHS.getComplexIntImag() * RHS.getComplexIntImag());
Result.getComplexIntImag() =
(LHS.getComplexIntReal() * RHS.getComplexIntImag() +
LHS.getComplexIntImag() * RHS.getComplexIntReal());
}
break;
case BO_Div:
if (Result.isComplexFloat()) {
ComplexValue LHS = Result;
APFloat &LHS_r = LHS.getComplexFloatReal();
APFloat &LHS_i = LHS.getComplexFloatImag();
APFloat &RHS_r = RHS.getComplexFloatReal();
APFloat &RHS_i = RHS.getComplexFloatImag();
APFloat &Res_r = Result.getComplexFloatReal();
APFloat &Res_i = Result.getComplexFloatImag();
APFloat Den = RHS_r;
Den.multiply(RHS_r, APFloat::rmNearestTiesToEven);
APFloat Tmp = RHS_i;
Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
Den.add(Tmp, APFloat::rmNearestTiesToEven);
Res_r = LHS_r;
Res_r.multiply(RHS_r, APFloat::rmNearestTiesToEven);
Tmp = LHS_i;
Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
Res_r.add(Tmp, APFloat::rmNearestTiesToEven);
Res_r.divide(Den, APFloat::rmNearestTiesToEven);
Res_i = LHS_i;
Res_i.multiply(RHS_r, APFloat::rmNearestTiesToEven);
Tmp = LHS_r;
Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven);
Res_i.subtract(Tmp, APFloat::rmNearestTiesToEven);
Res_i.divide(Den, APFloat::rmNearestTiesToEven);
} else {
if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0) {
// FIXME: what about diagnostics?
return false;
}
ComplexValue LHS = Result;
APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
RHS.getComplexIntImag() * RHS.getComplexIntImag();
Result.getComplexIntReal() =
(LHS.getComplexIntReal() * RHS.getComplexIntReal() +
LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
Result.getComplexIntImag() =
(LHS.getComplexIntImag() * RHS.getComplexIntReal() -
LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
}
break;
}
return true;
}
bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
// Get the operand value into 'Result'.
if (!Visit(E->getSubExpr()))
return false;
switch (E->getOpcode()) {
default:
// FIXME: what about diagnostics?
return false;
case UO_Extension:
return true;
case UO_Plus:
// The result is always just the subexpr.
return true;
case UO_Minus:
if (Result.isComplexFloat()) {
Result.getComplexFloatReal().changeSign();
Result.getComplexFloatImag().changeSign();
}
else {
Result.getComplexIntReal() = -Result.getComplexIntReal();
Result.getComplexIntImag() = -Result.getComplexIntImag();
}
return true;
case UO_Not:
if (Result.isComplexFloat())
Result.getComplexFloatImag().changeSign();
else
Result.getComplexIntImag() = -Result.getComplexIntImag();
return true;
}
}
//===----------------------------------------------------------------------===//
// Top level Expr::Evaluate method.
//===----------------------------------------------------------------------===//
static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
if (E->getType()->isVectorType()) {
if (!EvaluateVector(E, Result, Info))
return false;
} else if (E->getType()->isIntegralOrEnumerationType()) {
if (!IntExprEvaluator(Info, Result).Visit(E))
return false;
if (Result.isLValue() &&
!IsGlobalLValue(Result.getLValueBase()))
return false;
} else if (E->getType()->hasPointerRepresentation()) {
LValue LV;
if (!EvaluatePointer(E, LV, Info))
return false;
if (!IsGlobalLValue(LV.Base))
return false;
LV.moveInto(Result);
} else if (E->getType()->isRealFloatingType()) {
llvm::APFloat F(0.0);
if (!EvaluateFloat(E, F, Info))
return false;
Result = APValue(F);
} else if (E->getType()->isAnyComplexType()) {
ComplexValue C;
if (!EvaluateComplex(E, C, Info))
return false;
C.moveInto(Result);
} else
return false;
return true;
}
/// Evaluate - Return true if this is a constant which we can fold using
/// any crazy technique (that has nothing to do with language standards) that
/// we want to. If this function returns true, it returns the folded constant
/// in Result.
bool Expr::Evaluate(EvalResult &Result, const ASTContext &Ctx) const {
EvalInfo Info(Ctx, Result);
return ::Evaluate(Result.Val, Info, this);
}
bool Expr::EvaluateAsBooleanCondition(bool &Result,
const ASTContext &Ctx) const {
EvalStatus Scratch;
EvalInfo Info(Ctx, Scratch);
return HandleConversionToBool(this, Result, Info);
}
bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx) const {
EvalStatus Scratch;
EvalInfo Info(Ctx, Scratch);
return EvaluateInteger(this, Result, Info) && !Scratch.HasSideEffects;
}
bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
EvalInfo Info(Ctx, Result);
LValue LV;
if (EvaluateLValue(this, LV, Info) &&
!Result.HasSideEffects &&
IsGlobalLValue(LV.Base)) {
LV.moveInto(Result.Val);
return true;
}
return false;
}
bool Expr::EvaluateAsAnyLValue(EvalResult &Result,
const ASTContext &Ctx) const {
EvalInfo Info(Ctx, Result);
LValue LV;
if (EvaluateLValue(this, LV, Info)) {
LV.moveInto(Result.Val);
return true;
}
return false;
}
/// isEvaluatable - Call Evaluate to see if this expression can be constant
/// folded, but discard the result.
bool Expr::isEvaluatable(const ASTContext &Ctx) const {
EvalResult Result;
return Evaluate(Result, Ctx) && !Result.HasSideEffects;
}
bool Expr::HasSideEffects(const ASTContext &Ctx) const {
return HasSideEffect(Ctx).Visit(this);
}
APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx) const {
EvalResult EvalResult;
bool Result = Evaluate(EvalResult, Ctx);
(void)Result;
assert(Result && "Could not evaluate expression");
assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer");
return EvalResult.Val.getInt();
}
bool Expr::EvalResult::isGlobalLValue() const {
assert(Val.isLValue());
return IsGlobalLValue(Val.getLValueBase());
}
/// isIntegerConstantExpr - this recursive routine will test if an expression is
/// an integer constant expression.
/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
/// comma, etc
///
/// FIXME: Handle offsetof. Two things to do: Handle GCC's __builtin_offsetof
/// to support gcc 4.0+ and handle the idiom GCC recognizes with a null pointer
/// cast+dereference.
// CheckICE - This function does the fundamental ICE checking: the returned
// ICEDiag contains a Val of 0, 1, or 2, and a possibly null SourceLocation.
// Note that to reduce code duplication, this helper does no evaluation
// itself; the caller checks whether the expression is evaluatable, and
// in the rare cases where CheckICE actually cares about the evaluated
// value, it calls into Evalute.
//
// Meanings of Val:
// 0: This expression is an ICE if it can be evaluated by Evaluate.
// 1: This expression is not an ICE, but if it isn't evaluated, it's
// a legal subexpression for an ICE. This return value is used to handle
// the comma operator in C99 mode.
// 2: This expression is not an ICE, and is not a legal subexpression for one.
namespace {
struct ICEDiag {
unsigned Val;
SourceLocation Loc;
public:
ICEDiag(unsigned v, SourceLocation l) : Val(v), Loc(l) {}
ICEDiag() : Val(0) {}
};
}
static ICEDiag NoDiag() { return ICEDiag(); }
static ICEDiag CheckEvalInICE(const Expr* E, ASTContext &Ctx) {
Expr::EvalResult EVResult;
if (!E->Evaluate(EVResult, Ctx) || EVResult.HasSideEffects ||
!EVResult.Val.isInt()) {
return ICEDiag(2, E->getLocStart());
}
return NoDiag();
}
static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) {
assert(!E->isValueDependent() && "Should not see value dependent exprs!");
if (!E->getType()->isIntegralOrEnumerationType()) {
return ICEDiag(2, E->getLocStart());
}
switch (E->getStmtClass()) {
#define ABSTRACT_STMT(Node)
#define STMT(Node, Base) case Expr::Node##Class:
#define EXPR(Node, Base)
#include "clang/AST/StmtNodes.inc"
case Expr::PredefinedExprClass:
case Expr::FloatingLiteralClass:
case Expr::ImaginaryLiteralClass:
case Expr::StringLiteralClass:
case Expr::ArraySubscriptExprClass:
case Expr::MemberExprClass:
case Expr::CompoundAssignOperatorClass:
case Expr::CompoundLiteralExprClass:
case Expr::ExtVectorElementExprClass:
case Expr::DesignatedInitExprClass:
case Expr::ImplicitValueInitExprClass:
case Expr::ParenListExprClass:
case Expr::VAArgExprClass:
case Expr::AddrLabelExprClass:
case Expr::StmtExprClass:
case Expr::CXXMemberCallExprClass:
case Expr::CUDAKernelCallExprClass:
case Expr::CXXDynamicCastExprClass:
case Expr::CXXTypeidExprClass:
case Expr::CXXUuidofExprClass:
case Expr::CXXNullPtrLiteralExprClass:
case Expr::CXXThisExprClass:
case Expr::CXXThrowExprClass:
case Expr::CXXNewExprClass:
case Expr::CXXDeleteExprClass:
case Expr::CXXPseudoDestructorExprClass:
case Expr::UnresolvedLookupExprClass:
case Expr::DependentScopeDeclRefExprClass:
case Expr::CXXConstructExprClass:
case Expr::CXXBindTemporaryExprClass:
case Expr::ExprWithCleanupsClass:
case Expr::CXXTemporaryObjectExprClass:
case Expr::CXXUnresolvedConstructExprClass:
case Expr::CXXDependentScopeMemberExprClass:
case Expr::UnresolvedMemberExprClass:
case Expr::ObjCStringLiteralClass:
case Expr::ObjCEncodeExprClass:
case Expr::ObjCMessageExprClass:
case Expr::ObjCSelectorExprClass:
case Expr::ObjCProtocolExprClass:
case Expr::ObjCIvarRefExprClass:
case Expr::ObjCPropertyRefExprClass:
case Expr::ObjCIsaExprClass:
case Expr::ShuffleVectorExprClass:
case Expr::BlockExprClass:
case Expr::BlockDeclRefExprClass:
case Expr::NoStmtClass:
case Expr::OpaqueValueExprClass:
case Expr::PackExpansionExprClass:
case Expr::SubstNonTypeTemplateParmPackExprClass:
case Expr::AsTypeExprClass:
case Expr::ObjCIndirectCopyRestoreExprClass:
case Expr::MaterializeTemporaryExprClass:
case Expr::AtomicExprClass:
return ICEDiag(2, E->getLocStart());
case Expr::InitListExprClass:
if (Ctx.getLangOptions().CPlusPlus0x) {
const InitListExpr *ILE = cast<InitListExpr>(E);
if (ILE->getNumInits() == 0)
return NoDiag();
if (ILE->getNumInits() == 1)
return CheckICE(ILE->getInit(0), Ctx);
// Fall through for more than 1 expression.
}
return ICEDiag(2, E->getLocStart());
case Expr::SizeOfPackExprClass:
case Expr::GNUNullExprClass:
// GCC considers the GNU __null value to be an integral constant expression.
return NoDiag();
case Expr::SubstNonTypeTemplateParmExprClass:
return
CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
case Expr::ParenExprClass:
return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
case Expr::GenericSelectionExprClass:
return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
case Expr::IntegerLiteralClass:
case Expr::CharacterLiteralClass:
case Expr::CXXBoolLiteralExprClass:
case Expr::CXXScalarValueInitExprClass:
case Expr::UnaryTypeTraitExprClass:
case Expr::BinaryTypeTraitExprClass:
case Expr::ArrayTypeTraitExprClass:
case Expr::ExpressionTraitExprClass:
case Expr::CXXNoexceptExprClass:
return NoDiag();
case Expr::CallExprClass:
case Expr::CXXOperatorCallExprClass: {
const CallExpr *CE = cast<CallExpr>(E);
if (CE->isBuiltinCall(Ctx))
return CheckEvalInICE(E, Ctx);
return ICEDiag(2, E->getLocStart());
}
case Expr::DeclRefExprClass:
if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
return NoDiag();
if (Ctx.getLangOptions().CPlusPlus &&
E->getType().getCVRQualifiers() == Qualifiers::Const) {
const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl();
// Parameter variables are never constants. Without this check,
// getAnyInitializer() can find a default argument, which leads
// to chaos.
if (isa<ParmVarDecl>(D))
return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
// C++ 7.1.5.1p2
// A variable of non-volatile const-qualified integral or enumeration
// type initialized by an ICE can be used in ICEs.
if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) {
Qualifiers Quals = Ctx.getCanonicalType(Dcl->getType()).getQualifiers();
if (Quals.hasVolatile() || !Quals.hasConst())
return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
// Look for a declaration of this variable that has an initializer.
const VarDecl *ID = 0;
const Expr *Init = Dcl->getAnyInitializer(ID);
if (Init) {
if (ID->isInitKnownICE()) {
// We have already checked whether this subexpression is an
// integral constant expression.
if (ID->isInitICE())
return NoDiag();
else
return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
}
// It's an ICE whether or not the definition we found is
// out-of-line. See DR 721 and the discussion in Clang PR
// 6206 for details.
if (Dcl->isCheckingICE()) {
return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation());
}
Dcl->setCheckingICE();
ICEDiag Result = CheckICE(Init, Ctx);
// Cache the result of the ICE test.
Dcl->setInitKnownICE(Result.Val == 0);
return Result;
}
}
}
return ICEDiag(2, E->getLocStart());
case Expr::UnaryOperatorClass: {
const UnaryOperator *Exp = cast<UnaryOperator>(E);
switch (Exp->getOpcode()) {
case UO_PostInc:
case UO_PostDec:
case UO_PreInc:
case UO_PreDec:
case UO_AddrOf:
case UO_Deref:
return ICEDiag(2, E->getLocStart());
case UO_Extension:
case UO_LNot:
case UO_Plus:
case UO_Minus:
case UO_Not:
case UO_Real:
case UO_Imag:
return CheckICE(Exp->getSubExpr(), Ctx);
}
// OffsetOf falls through here.
}
case Expr::OffsetOfExprClass: {
// Note that per C99, offsetof must be an ICE. And AFAIK, using
// Evaluate matches the proposed gcc behavior for cases like
// "offsetof(struct s{int x[4];}, x[!.0])". This doesn't affect
// compliance: we should warn earlier for offsetof expressions with
// array subscripts that aren't ICEs, and if the array subscripts
// are ICEs, the value of the offsetof must be an integer constant.
return CheckEvalInICE(E, Ctx);
}
case Expr::UnaryExprOrTypeTraitExprClass: {
const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
if ((Exp->getKind() == UETT_SizeOf) &&
Exp->getTypeOfArgument()->isVariableArrayType())
return ICEDiag(2, E->getLocStart());
return NoDiag();
}
case Expr::BinaryOperatorClass: {
const BinaryOperator *Exp = cast<BinaryOperator>(E);
switch (Exp->getOpcode()) {
case BO_PtrMemD:
case BO_PtrMemI:
case BO_Assign:
case BO_MulAssign:
case BO_DivAssign:
case BO_RemAssign:
case BO_AddAssign:
case BO_SubAssign:
case BO_ShlAssign:
case BO_ShrAssign:
case BO_AndAssign:
case BO_XorAssign:
case BO_OrAssign:
return ICEDiag(2, E->getLocStart());
case BO_Mul:
case BO_Div:
case BO_Rem:
case BO_Add:
case BO_Sub:
case BO_Shl:
case BO_Shr:
case BO_LT:
case BO_GT:
case BO_LE:
case BO_GE:
case BO_EQ:
case BO_NE:
case BO_And:
case BO_Xor:
case BO_Or:
case BO_Comma: {
ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
if (Exp->getOpcode() == BO_Div ||
Exp->getOpcode() == BO_Rem) {
// Evaluate gives an error for undefined Div/Rem, so make sure
// we don't evaluate one.
if (LHSResult.Val == 0 && RHSResult.Val == 0) {
llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
if (REval == 0)
return ICEDiag(1, E->getLocStart());
if (REval.isSigned() && REval.isAllOnesValue()) {
llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
if (LEval.isMinSignedValue())
return ICEDiag(1, E->getLocStart());
}
}
}
if (Exp->getOpcode() == BO_Comma) {
if (Ctx.getLangOptions().C99) {
// C99 6.6p3 introduces a strange edge case: comma can be in an ICE
// if it isn't evaluated.
if (LHSResult.Val == 0 && RHSResult.Val == 0)
return ICEDiag(1, E->getLocStart());
} else {
// In both C89 and C++, commas in ICEs are illegal.
return ICEDiag(2, E->getLocStart());
}
}
if (LHSResult.Val >= RHSResult.Val)
return LHSResult;
return RHSResult;
}
case BO_LAnd:
case BO_LOr: {
ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
// C++0x [expr.const]p2:
// [...] subexpressions of logical AND (5.14), logical OR
// (5.15), and condi- tional (5.16) operations that are not
// evaluated are not considered.
if (Ctx.getLangOptions().CPlusPlus0x && LHSResult.Val == 0) {
if (Exp->getOpcode() == BO_LAnd &&
Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0)
return LHSResult;
if (Exp->getOpcode() == BO_LOr &&
Exp->getLHS()->EvaluateKnownConstInt(Ctx) != 0)
return LHSResult;
}
ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
if (LHSResult.Val == 0 && RHSResult.Val == 1) {
// Rare case where the RHS has a comma "side-effect"; we need
// to actually check the condition to see whether the side
// with the comma is evaluated.
if ((Exp->getOpcode() == BO_LAnd) !=
(Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
return RHSResult;
return NoDiag();
}
if (LHSResult.Val >= RHSResult.Val)
return LHSResult;
return RHSResult;
}
}
}
case Expr::ImplicitCastExprClass:
case Expr::CStyleCastExprClass:
case Expr::CXXFunctionalCastExprClass:
case Expr::CXXStaticCastExprClass:
case Expr::CXXReinterpretCastExprClass:
case Expr::CXXConstCastExprClass:
case Expr::ObjCBridgedCastExprClass: {
const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
switch (cast<CastExpr>(E)->getCastKind()) {
case CK_LValueToRValue:
case CK_NoOp:
case CK_IntegralToBoolean:
case CK_IntegralCast:
return CheckICE(SubExpr, Ctx);
default:
if (isa<FloatingLiteral>(SubExpr->IgnoreParens()))
return NoDiag();
return ICEDiag(2, E->getLocStart());
}
}
case Expr::BinaryConditionalOperatorClass: {
const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
if (CommonResult.Val == 2) return CommonResult;
ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
if (FalseResult.Val == 2) return FalseResult;
if (CommonResult.Val == 1) return CommonResult;
if (FalseResult.Val == 1 &&
Exp->getCommon()->EvaluateKnownConstInt(Ctx) == 0) return NoDiag();
return FalseResult;
}
case Expr::ConditionalOperatorClass: {
const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
// If the condition (ignoring parens) is a __builtin_constant_p call,
// then only the true side is actually considered in an integer constant
// expression, and it is fully evaluated. This is an important GNU
// extension. See GCC PR38377 for discussion.
if (const CallExpr *CallCE
= dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
if (CallCE->isBuiltinCall(Ctx) == Builtin::BI__builtin_constant_p) {
Expr::EvalResult EVResult;
if (!E->Evaluate(EVResult, Ctx) || EVResult.HasSideEffects ||
!EVResult.Val.isInt()) {
return ICEDiag(2, E->getLocStart());
}
return NoDiag();
}
ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
if (CondResult.Val == 2)
return CondResult;
// C++0x [expr.const]p2:
// subexpressions of [...] conditional (5.16) operations that
// are not evaluated are not considered
bool TrueBranch = Ctx.getLangOptions().CPlusPlus0x
? Exp->getCond()->EvaluateKnownConstInt(Ctx) != 0
: false;
ICEDiag TrueResult = NoDiag();
if (!Ctx.getLangOptions().CPlusPlus0x || TrueBranch)
TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
ICEDiag FalseResult = NoDiag();
if (!Ctx.getLangOptions().CPlusPlus0x || !TrueBranch)
FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
if (TrueResult.Val == 2)
return TrueResult;
if (FalseResult.Val == 2)
return FalseResult;
if (CondResult.Val == 1)
return CondResult;
if (TrueResult.Val == 0 && FalseResult.Val == 0)
return NoDiag();
// Rare case where the diagnostics depend on which side is evaluated
// Note that if we get here, CondResult is 0, and at least one of
// TrueResult and FalseResult is non-zero.
if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0) {
return FalseResult;
}
return TrueResult;
}
case Expr::CXXDefaultArgExprClass:
return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
case Expr::ChooseExprClass: {
return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(Ctx), Ctx);
}
}
// Silence a GCC warning
return ICEDiag(2, E->getLocStart());
}
bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx,
SourceLocation *Loc, bool isEvaluated) const {
ICEDiag d = CheckICE(this, Ctx);
if (d.Val != 0) {
if (Loc) *Loc = d.Loc;
return false;
}
EvalResult EvalResult;
if (!Evaluate(EvalResult, Ctx))
llvm_unreachable("ICE cannot be evaluated!");
assert(!EvalResult.HasSideEffects && "ICE with side effects!");
assert(EvalResult.Val.isInt() && "ICE that isn't integer!");
Result = EvalResult.Val.getInt();
return true;
}
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