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teak-llvm/clang/lib/AST/ExprConstant.cpp
John McCall c63de66c4f An insomniac stab at making block declarations list the variables they close 
on, as well as more reliably limiting invalid references to locals from
nested scopes.

llvm-svn: 124721
2011-02-02 13:00:07 +00:00

2909 lines
94 KiB
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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.
struct EvalInfo {
const ASTContext &Ctx;
/// EvalResult - Contains information about the evaluation.
Expr::EvalResult &EvalResult;
EvalInfo(const ASTContext &ctx, Expr::EvalResult& evalresult)
: Ctx(ctx), EvalResult(evalresult) {}
};
namespace {
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) {
if (isComplexFloat())
v = APValue(FloatReal, FloatImag);
else
v = APValue(IntReal, IntImag);
}
};
struct LValue {
Expr *Base;
CharUnits Offset;
Expr *getLValueBase() { return Base; }
CharUnits getLValueOffset() { return Offset; }
void moveInto(APValue &v) {
v = APValue(Base, Offset);
}
};
}
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->hasAttr<WeakImportAttr>())
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->isSignedIntegerType();
// FIXME: Warning for overflow.
uint64_t Space[4];
bool ignored;
(void)Value.convertToInteger(Space, DestWidth, DestSigned,
llvm::APFloat::rmTowardZero, &ignored);
return APSInt(llvm::APInt(DestWidth, 4, Space), !DestSigned);
}
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->isUnsignedIntegerType());
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 StmtVisitor<HasSideEffect, bool> {
EvalInfo &Info;
public:
HasSideEffect(EvalInfo &info) : Info(info) {}
// Unhandled nodes conservatively default to having side effects.
bool VisitStmt(Stmt *S) {
return true;
}
bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); }
bool VisitDeclRefExpr(DeclRefExpr *E) {
if (Info.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(BlockExpr *E) { return true; }
bool VisitPredefinedExpr(PredefinedExpr *E) { return false; }
bool VisitCompoundLiteralExpr(CompoundLiteralExpr *E)
{ return Visit(E->getInitializer()); }
bool VisitMemberExpr(MemberExpr *E) { return Visit(E->getBase()); }
bool VisitIntegerLiteral(IntegerLiteral *E) { return false; }
bool VisitFloatingLiteral(FloatingLiteral *E) { return false; }
bool VisitStringLiteral(StringLiteral *E) { return false; }
bool VisitCharacterLiteral(CharacterLiteral *E) { return false; }
bool VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E) { return false; }
bool VisitArraySubscriptExpr(ArraySubscriptExpr *E)
{ return Visit(E->getLHS()) || Visit(E->getRHS()); }
bool VisitChooseExpr(ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Info.Ctx)); }
bool VisitCastExpr(CastExpr *E) { return Visit(E->getSubExpr()); }
bool VisitBinAssign(BinaryOperator *E) { return true; }
bool VisitCompoundAssignOperator(BinaryOperator *E) { return true; }
bool VisitBinaryOperator(BinaryOperator *E)
{ return Visit(E->getLHS()) || Visit(E->getRHS()); }
bool VisitUnaryPreInc(UnaryOperator *E) { return true; }
bool VisitUnaryPostInc(UnaryOperator *E) { return true; }
bool VisitUnaryPreDec(UnaryOperator *E) { return true; }
bool VisitUnaryPostDec(UnaryOperator *E) { return true; }
bool VisitUnaryDeref(UnaryOperator *E) {
if (Info.Ctx.getCanonicalType(E->getType()).isVolatileQualified())
return true;
return Visit(E->getSubExpr());
}
bool VisitUnaryOperator(UnaryOperator *E) { return Visit(E->getSubExpr()); }
// Has side effects if any element does.
bool VisitInitListExpr(InitListExpr *E) {
for (unsigned i = 0, e = E->getNumInits(); i != e; ++i)
if (Visit(E->getInit(i))) return true;
return false;
}
bool VisitSizeOfPackExpr(SizeOfPackExpr *) { return false; }
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// LValue Evaluation
//===----------------------------------------------------------------------===//
namespace {
class LValueExprEvaluator
: public StmtVisitor<LValueExprEvaluator, bool> {
EvalInfo &Info;
LValue &Result;
bool Success(Expr *E) {
Result.Base = E;
Result.Offset = CharUnits::Zero();
return true;
}
public:
LValueExprEvaluator(EvalInfo &info, LValue &Result) :
Info(info), Result(Result) {}
bool VisitStmt(Stmt *S) {
return false;
}
bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); }
bool VisitDeclRefExpr(DeclRefExpr *E);
bool VisitPredefinedExpr(PredefinedExpr *E) { return Success(E); }
bool VisitCompoundLiteralExpr(CompoundLiteralExpr *E);
bool VisitMemberExpr(MemberExpr *E);
bool VisitStringLiteral(StringLiteral *E) { return Success(E); }
bool VisitObjCEncodeExpr(ObjCEncodeExpr *E) { return Success(E); }
bool VisitArraySubscriptExpr(ArraySubscriptExpr *E);
bool VisitUnaryDeref(UnaryOperator *E);
bool VisitUnaryExtension(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
bool VisitChooseExpr(const ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Info.Ctx)); }
bool VisitCastExpr(CastExpr *E) {
switch (E->getCastKind()) {
default:
return false;
case CK_NoOp:
return Visit(E->getSubExpr());
}
}
// FIXME: Missing: __real__, __imag__
};
} // end anonymous namespace
static bool EvaluateLValue(const Expr* E, LValue& Result, EvalInfo &Info) {
return LValueExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E));
}
bool LValueExprEvaluator::VisitDeclRefExpr(DeclRefExpr *E) {
if (isa<FunctionDecl>(E->getDecl())) {
return Success(E);
} else if (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))
return false;
// FIXME: Check whether VD might be overridden!
if (const Expr *Init = VD->getAnyInitializer())
return Visit(const_cast<Expr *>(Init));
}
return false;
}
bool LValueExprEvaluator::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
return Success(E);
}
bool LValueExprEvaluator::VisitMemberExpr(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();
}
RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
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;
// FIXME: This is linear time.
unsigned i = 0;
for (RecordDecl::field_iterator Field = RD->field_begin(),
FieldEnd = RD->field_end();
Field != FieldEnd; (void)++Field, ++i) {
if (*Field == FD)
break;
}
Result.Offset += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
return true;
}
bool LValueExprEvaluator::VisitArraySubscriptExpr(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(UnaryOperator *E) {
return EvaluatePointer(E->getSubExpr(), Result, Info);
}
//===----------------------------------------------------------------------===//
// Pointer Evaluation
//===----------------------------------------------------------------------===//
namespace {
class PointerExprEvaluator
: public StmtVisitor<PointerExprEvaluator, bool> {
EvalInfo &Info;
LValue &Result;
bool Success(Expr *E) {
Result.Base = E;
Result.Offset = CharUnits::Zero();
return true;
}
public:
PointerExprEvaluator(EvalInfo &info, LValue &Result)
: Info(info), Result(Result) {}
bool VisitStmt(Stmt *S) {
return false;
}
bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); }
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitCastExpr(CastExpr* E);
bool VisitUnaryExtension(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
bool VisitUnaryAddrOf(const UnaryOperator *E);
bool VisitObjCStringLiteral(ObjCStringLiteral *E)
{ return Success(E); }
bool VisitAddrLabelExpr(AddrLabelExpr *E)
{ return Success(E); }
bool VisitCallExpr(CallExpr *E);
bool VisitBlockExpr(BlockExpr *E) {
if (!E->getBlockDecl()->hasCaptures())
return Success(E);
return false;
}
bool VisitImplicitValueInitExpr(ImplicitValueInitExpr *E)
{ return Success((Expr*)0); }
bool VisitConditionalOperator(ConditionalOperator *E);
bool VisitChooseExpr(ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Info.Ctx)); }
bool VisitCXXNullPtrLiteralExpr(CXXNullPtrLiteralExpr *E)
{ return Success((Expr*)0); }
// 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(const_cast<Expr*>(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(CastExpr* E) {
Expr* SubExpr = E->getSubExpr();
switch (E->getCastKind()) {
default:
break;
case CK_NoOp:
case CK_BitCast:
case CK_LValueBitCast:
case CK_AnyPointerToObjCPointerCast:
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(CallExpr *E) {
if (E->isBuiltinCall(Info.Ctx) ==
Builtin::BI__builtin___CFStringMakeConstantString ||
E->isBuiltinCall(Info.Ctx) ==
Builtin::BI__builtin___NSStringMakeConstantString)
return Success(E);
return false;
}
bool PointerExprEvaluator::VisitConditionalOperator(ConditionalOperator *E) {
bool BoolResult;
if (!HandleConversionToBool(E->getCond(), BoolResult, Info))
return false;
Expr* EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
return Visit(EvalExpr);
}
//===----------------------------------------------------------------------===//
// Vector Evaluation
//===----------------------------------------------------------------------===//
namespace {
class VectorExprEvaluator
: public StmtVisitor<VectorExprEvaluator, APValue> {
EvalInfo &Info;
APValue GetZeroVector(QualType VecType);
public:
VectorExprEvaluator(EvalInfo &info) : Info(info) {}
APValue VisitStmt(Stmt *S) {
return APValue();
}
APValue VisitParenExpr(ParenExpr *E)
{ return Visit(E->getSubExpr()); }
APValue VisitUnaryExtension(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
APValue VisitUnaryPlus(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
APValue VisitUnaryReal(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
APValue VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E)
{ return GetZeroVector(E->getType()); }
APValue VisitCastExpr(const CastExpr* E);
APValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
APValue VisitInitListExpr(const InitListExpr *E);
APValue VisitConditionalOperator(const ConditionalOperator *E);
APValue VisitChooseExpr(const ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Info.Ctx)); }
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(const_cast<Expr*>(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();
APValue Result = APValue();
// Check for vector->vector bitcast and scalar->vector splat.
if (SETy->isVectorType()) {
return this->Visit(const_cast<Expr*>(SE));
} else 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();
// For casts of a scalar to ExtVector, convert the scalar to the element type
// and splat it to all elements.
if (E->getType()->isExtVectorType()) {
if (EltTy->isIntegerType() && Result.isInt())
Result = APValue(HandleIntToIntCast(EltTy, SETy, Result.getInt(),
Info.Ctx));
else if (EltTy->isIntegerType())
Result = APValue(HandleFloatToIntCast(EltTy, SETy, Result.getFloat(),
Info.Ctx));
else if (EltTy->isRealFloatingType() && Result.isInt())
Result = APValue(HandleIntToFloatCast(EltTy, SETy, Result.getInt(),
Info.Ctx));
else if (EltTy->isRealFloatingType())
Result = APValue(HandleFloatToFloatCast(EltTy, SETy, Result.getFloat(),
Info.Ctx));
else
return APValue();
// Splat and create vector APValue.
llvm::SmallVector<APValue, 4> Elts(NElts, Result);
return APValue(&Elts[0], Elts.size());
}
// For casts of a scalar to regular gcc-style vector type, bitcast the scalar
// to the vector. To construct the APValue vector initializer, bitcast the
// initializing value to an APInt, and shift out the bits pertaining to each
// element.
APSInt Init;
Init = Result.isInt() ? Result.getInt() : Result.getFloat().bitcastToAPInt();
llvm::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 if (EltTy->isRealFloatingType())
Elts.push_back(APValue(APFloat(Tmp)));
else
return APValue();
Init >>= EltWidth;
}
return APValue(&Elts[0], Elts.size());
}
APValue
VectorExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
return this->Visit(const_cast<Expr*>(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();
llvm::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) {
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)));
llvm::SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
return APValue(&Elements[0], Elements.size());
}
APValue VectorExprEvaluator::VisitConditionalOperator(const ConditionalOperator *E) {
bool BoolResult;
if (!HandleConversionToBool(E->getCond(), BoolResult, Info))
return APValue();
Expr* EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
APValue Result;
if (EvaluateVector(EvalExpr, Result, Info))
return Result;
return APValue();
}
APValue VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
if (!E->getSubExpr()->isEvaluatable(Info.Ctx))
Info.EvalResult.HasSideEffects = true;
return GetZeroVector(E->getType());
}
//===----------------------------------------------------------------------===//
// Integer Evaluation
//===----------------------------------------------------------------------===//
namespace {
class IntExprEvaluator
: public StmtVisitor<IntExprEvaluator, bool> {
EvalInfo &Info;
APValue &Result;
public:
IntExprEvaluator(EvalInfo &info, APValue &result)
: Info(info), Result(result) {}
bool Success(const llvm::APSInt &SI, const Expr *E) {
assert(E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.");
assert(SI.isSigned() == E->getType()->isSignedIntegerType() &&
"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()->isUnsignedIntegerType());
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 Error(SourceLocation L, diag::kind D, const Expr *E) {
// Take the first error.
if (Info.EvalResult.Diag == 0) {
Info.EvalResult.DiagLoc = L;
Info.EvalResult.Diag = D;
Info.EvalResult.DiagExpr = E;
}
return false;
}
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//
bool VisitStmt(Stmt *) {
assert(0 && "This should be called on integers, stmts are not integers");
return false;
}
bool VisitExpr(Expr *E) {
return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); }
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) {
return CheckReferencedDecl(E, E->getDecl());
}
bool VisitMemberExpr(const MemberExpr *E) {
if (CheckReferencedDecl(E, E->getMemberDecl())) {
// Conservatively assume a MemberExpr will have side-effects
Info.EvalResult.HasSideEffects = true;
return true;
}
return false;
}
bool VisitCallExpr(CallExpr *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitOffsetOfExpr(const OffsetOfExpr *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitConditionalOperator(const ConditionalOperator *E);
bool VisitCastExpr(CastExpr* E);
bool VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E);
bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
return Success(E->getValue(), E);
}
bool VisitGNUNullExpr(const GNUNullExpr *E) {
return Success(0, E);
}
bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
return Success(0, E);
}
bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
return Success(0, E);
}
bool VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) {
return Success(E->getValue(), E);
}
bool VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr *E) {
return Success(E->getValue(), E);
}
bool VisitChooseExpr(const ChooseExpr *E) {
return Visit(E->getChosenSubExpr(Info.Ctx));
}
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(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(const_cast<Expr*>(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))
return Success(ECD->getInitVal(), 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 Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
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 Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
if (VD->isEvaluatingValue())
return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
VD->setEvaluatingValue();
Expr::EvalResult EResult;
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 Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E);
}
/// 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?
assert(0 && "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(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.getQuantity(), E);
}
bool IntExprEvaluator::VisitCallExpr(CallExpr *E) {
switch (E->isBuiltinCall(Info.Ctx)) {
default:
return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, 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)->EvaluateAsInt(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)->EvaluateAsInt(Info.Ctx).getZExtValue();
Operand = Info.Ctx.Target.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 (StringLiteral *S
= dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenImpCasts())) {
// The string literal may have embedded null characters. Find the first
// one and truncate there.
llvm::StringRef Str = S->getString();
llvm::StringRef::size_type Pos = Str.find(0);
if (Pos != llvm::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.
if (!E->getLHS()->isEvaluatable(Info.Ctx))
Info.EvalResult.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.EvalResult.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:
assert(0 && "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);
}
}
bool IntExprEvaluator::VisitConditionalOperator(const ConditionalOperator *E) {
bool Cond;
if (!HandleConversionToBool(E->getCond(), Cond, Info))
return false;
return Visit(Cond ? E->getTrueExpr() : E->getFalseExpr());
}
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());
}
/// VisitSizeAlignOfExpr - Evaluate a sizeof or alignof with a result as the
/// expression's type.
bool IntExprEvaluator::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) {
// Handle alignof separately.
if (!E->isSizeOf()) {
if (E->isArgumentType())
return Success(GetAlignOfType(E->getArgumentType()).getQuantity(), E);
else
return Success(GetAlignOfExpr(E->getArgumentExpr()).getQuantity(), E);
}
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).getQuantity(), E);
}
bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *E) {
CharUnits Result;
unsigned n = E->getNumComponents();
OffsetOfExpr* OOE = const_cast<OffsetOfExpr*>(E);
if (n == 0)
return false;
QualType CurrentType = E->getTypeSourceInfo()->getType();
for (unsigned i = 0; i != n; ++i) {
OffsetOfExpr::OffsetOfNode ON = OOE->getComponent(i);
switch (ON.getKind()) {
case OffsetOfExpr::OffsetOfNode::Array: {
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.getQuantity(), E);
}
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(CastExpr *E) {
Expr *SubExpr = E->getSubExpr();
QualType DestType = E->getType();
QualType SrcType = SubExpr->getType();
if (DestType->isBooleanType()) {
bool BoolResult;
if (!HandleConversionToBool(SubExpr, BoolResult, Info))
return false;
return Success(BoolResult, E);
}
// Handle simple integer->integer casts.
if (SrcType->isIntegralOrEnumerationType()) {
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);
}
// FIXME: Clean this up!
if (SrcType->isPointerType()) {
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);
}
if (SrcType->isArrayType() || SrcType->isFunctionType()) {
// This handles double-conversion cases, where there's both
// an l-value promotion and an implicit conversion to int.
LValue LV;
if (!EvaluateLValue(SubExpr, LV, Info))
return false;
if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(Info.Ctx.VoidPtrTy))
return false;
LV.moveInto(Result);
return true;
}
if (SrcType->isAnyComplexType()) {
ComplexValue C;
if (!EvaluateComplex(SubExpr, C, Info))
return false;
if (C.isComplexFloat())
return Success(HandleFloatToIntCast(DestType, SrcType,
C.getComplexFloatReal(), Info.Ctx),
E);
else
return Success(HandleIntToIntCast(DestType, SrcType,
C.getComplexIntReal(), Info.Ctx), E);
}
// FIXME: Handle vectors
if (!SrcType->isRealFloatingType())
return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E);
APFloat F(0.0);
if (!EvaluateFloat(SubExpr, F, Info))
return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E);
return Success(HandleFloatToIntCast(DestType, SrcType, F, Info.Ctx), E);
}
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);
}
if (!E->getSubExpr()->isEvaluatable(Info.Ctx))
Info.EvalResult.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 StmtVisitor<FloatExprEvaluator, bool> {
EvalInfo &Info;
APFloat &Result;
public:
FloatExprEvaluator(EvalInfo &info, APFloat &result)
: Info(info), Result(result) {}
bool VisitStmt(Stmt *S) {
return false;
}
bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); }
bool VisitCallExpr(const CallExpr *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitFloatingLiteral(const FloatingLiteral *E);
bool VisitCastExpr(CastExpr *E);
bool VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
bool VisitConditionalOperator(ConditionalOperator *E);
bool VisitChooseExpr(const ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Info.Ctx)); }
bool VisitUnaryExtension(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
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(const_cast<Expr*>(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 false;
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) {
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;
}
if (!E->getSubExpr()->isEvaluatable(Info.Ctx))
Info.EvalResult.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.
if (!E->getLHS()->isEvaluatable(Info.Ctx))
Info.EvalResult.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(CastExpr *E) {
Expr* SubExpr = E->getSubExpr();
if (SubExpr->getType()->isIntegralOrEnumerationType()) {
APSInt IntResult;
if (!EvaluateInteger(SubExpr, IntResult, Info))
return false;
Result = HandleIntToFloatCast(E->getType(), SubExpr->getType(),
IntResult, Info.Ctx);
return true;
}
if (SubExpr->getType()->isRealFloatingType()) {
if (!Visit(SubExpr))
return false;
Result = HandleFloatToFloatCast(E->getType(), SubExpr->getType(),
Result, Info.Ctx);
return true;
}
if (E->getCastKind() == CK_FloatingComplexToReal) {
ComplexValue V;
if (!EvaluateComplex(SubExpr, V, Info))
return false;
Result = V.getComplexFloatReal();
return true;
}
return false;
}
bool FloatExprEvaluator::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
return true;
}
bool FloatExprEvaluator::VisitConditionalOperator(ConditionalOperator *E) {
bool Cond;
if (!HandleConversionToBool(E->getCond(), Cond, Info))
return false;
return Visit(Cond ? E->getTrueExpr() : E->getFalseExpr());
}
//===----------------------------------------------------------------------===//
// Complex Evaluation (for float and integer)
//===----------------------------------------------------------------------===//
namespace {
class ComplexExprEvaluator
: public StmtVisitor<ComplexExprEvaluator, bool> {
EvalInfo &Info;
ComplexValue &Result;
public:
ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
: Info(info), Result(Result) {}
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//
bool VisitStmt(Stmt *S) {
return false;
}
bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); }
bool VisitImaginaryLiteral(ImaginaryLiteral *E);
bool VisitCastExpr(CastExpr *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitConditionalOperator(const ConditionalOperator *E);
bool VisitChooseExpr(const ChooseExpr *E)
{ return Visit(E->getChosenSubExpr(Info.Ctx)); }
bool VisitUnaryExtension(const UnaryOperator *E)
{ return Visit(E->getSubExpr()); }
// FIXME Missing: ImplicitValueInitExpr
};
} // end anonymous namespace
static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
EvalInfo &Info) {
assert(E->getType()->isAnyComplexType());
return ComplexExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E));
}
bool ComplexExprEvaluator::VisitImaginaryLiteral(ImaginaryLiteral *E) {
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(CastExpr *E) {
switch (E->getCastKind()) {
case CK_BitCast:
case CK_LValueBitCast:
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_AnyPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_ObjCObjectLValueCast:
case CK_FloatingComplexToReal:
case CK_FloatingComplexToBoolean:
case CK_IntegralComplexToReal:
case CK_IntegralComplexToBoolean:
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_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.
if (!E->getLHS()->isEvaluatable(Info.Ctx))
Info.EvalResult.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;
}
}
bool ComplexExprEvaluator::VisitConditionalOperator(const ConditionalOperator *E) {
bool Cond;
if (!HandleConversionToBool(E->getCond(), Cond, Info))
return false;
return Visit(Cond ? E->getTrueExpr() : E->getFalseExpr());
}
//===----------------------------------------------------------------------===//
// Top level Expr::Evaluate method.
//===----------------------------------------------------------------------===//
/// 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 {
const Expr *E = this;
EvalInfo Info(Ctx, Result);
if (E->getType()->isVectorType()) {
if (!EvaluateVector(E, Info.EvalResult.Val, Info))
return false;
} else if (E->getType()->isIntegerType()) {
if (!IntExprEvaluator(Info, Info.EvalResult.Val).Visit(const_cast<Expr*>(E)))
return false;
if (Result.Val.isLValue() && !IsGlobalLValue(Result.Val.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(Info.EvalResult.Val);
} else if (E->getType()->isRealFloatingType()) {
llvm::APFloat F(0.0);
if (!EvaluateFloat(E, F, Info))
return false;
Info.EvalResult.Val = APValue(F);
} else if (E->getType()->isAnyComplexType()) {
ComplexValue C;
if (!EvaluateComplex(E, C, Info))
return false;
C.moveInto(Info.EvalResult.Val);
} else
return false;
return true;
}
bool Expr::EvaluateAsBooleanCondition(bool &Result,
const ASTContext &Ctx) const {
EvalResult Scratch;
EvalInfo Info(Ctx, Scratch);
return HandleConversionToBool(this, Result, Info);
}
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 {
Expr::EvalResult Result;
EvalInfo Info(Ctx, Result);
return HasSideEffect(Info).Visit(const_cast<Expr*>(this));
}
APSInt Expr::EvaluateAsInt(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 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::InitListExprClass:
case Expr::DesignatedInitExprClass:
case Expr::ImplicitValueInitExprClass:
case Expr::ParenListExprClass:
case Expr::VAArgExprClass:
case Expr::AddrLabelExprClass:
case Expr::StmtExprClass:
case Expr::CXXMemberCallExprClass:
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:
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::ParenExprClass:
return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
case Expr::IntegerLiteralClass:
case Expr::CharacterLiteralClass:
case Expr::CXXBoolLiteralExprClass:
case Expr::CXXScalarValueInitExprClass:
case Expr::UnaryTypeTraitExprClass:
case Expr::BinaryTypeTraitExprClass:
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::SizeOfAlignOfExprClass: {
const SizeOfAlignOfExpr *Exp = cast<SizeOfAlignOfExpr>(E);
if (Exp->isSizeOf() && 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 != 2 && RHSResult.Val != 2) {
llvm::APSInt REval = Exp->getRHS()->EvaluateAsInt(Ctx);
if (REval == 0)
return ICEDiag(1, E->getLocStart());
if (REval.isSigned() && REval.isAllOnesValue()) {
llvm::APSInt LEval = Exp->getLHS()->EvaluateAsInt(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);
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()->EvaluateAsInt(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: {
const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
if (SubExpr->getType()->isIntegralOrEnumerationType())
return CheckICE(SubExpr, Ctx);
if (isa<FloatingLiteral>(SubExpr->IgnoreParens()))
return NoDiag();
return ICEDiag(2, E->getLocStart());
}
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);
ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
if (CondResult.Val == 2)
return CondResult;
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()->EvaluateAsInt(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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