//===--- Expr.cpp - Expression AST Node Implementation --------------------===// // // 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 class and subclasses. // //===----------------------------------------------------------------------===// #include "clang/AST/Expr.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/ASTContext.h" #include "clang/AST/RecordLayout.h" #include "clang/AST/StmtVisitor.h" #include "clang/Basic/TargetInfo.h" using namespace clang; //===----------------------------------------------------------------------===// // Primary Expressions. //===----------------------------------------------------------------------===// /// getValueAsApproximateDouble - This returns the value as an inaccurate /// double. Note that this may cause loss of precision, but is useful for /// debugging dumps, etc. double FloatingLiteral::getValueAsApproximateDouble() const { llvm::APFloat V = getValue(); V.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven); return V.convertToDouble(); } StringLiteral::StringLiteral(const char *strData, unsigned byteLength, bool Wide, QualType t, SourceLocation firstLoc, SourceLocation lastLoc) : Expr(StringLiteralClass, t) { // OPTIMIZE: could allocate this appended to the StringLiteral. char *AStrData = new char[byteLength]; memcpy(AStrData, strData, byteLength); StrData = AStrData; ByteLength = byteLength; IsWide = Wide; firstTokLoc = firstLoc; lastTokLoc = lastLoc; } StringLiteral::~StringLiteral() { delete[] StrData; } bool UnaryOperator::isPostfix(Opcode Op) { switch (Op) { case PostInc: case PostDec: return true; default: return false; } } bool UnaryOperator::isPrefix(Opcode Op) { switch (Op) { case PreInc: case PreDec: return true; default: return false; } } /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it /// corresponds to, e.g. "sizeof" or "[pre]++". const char *UnaryOperator::getOpcodeStr(Opcode Op) { switch (Op) { default: assert(0 && "Unknown unary operator"); case PostInc: return "++"; case PostDec: return "--"; case PreInc: return "++"; case PreDec: return "--"; case AddrOf: return "&"; case Deref: return "*"; case Plus: return "+"; case Minus: return "-"; case Not: return "~"; case LNot: return "!"; case Real: return "__real"; case Imag: return "__imag"; case SizeOf: return "sizeof"; case AlignOf: return "alignof"; case Extension: return "__extension__"; case OffsetOf: return "__builtin_offsetof"; } } //===----------------------------------------------------------------------===// // Postfix Operators. //===----------------------------------------------------------------------===// CallExpr::CallExpr(Expr *fn, Expr **args, unsigned numargs, QualType t, SourceLocation rparenloc) : Expr(CallExprClass, t), NumArgs(numargs) { SubExprs = new Stmt*[numargs+1]; SubExprs[FN] = fn; for (unsigned i = 0; i != numargs; ++i) SubExprs[i+ARGS_START] = args[i]; RParenLoc = rparenloc; } /// setNumArgs - This changes the number of arguments present in this call. /// Any orphaned expressions are deleted by this, and any new operands are set /// to null. void CallExpr::setNumArgs(unsigned NumArgs) { // No change, just return. if (NumArgs == getNumArgs()) return; // If shrinking # arguments, just delete the extras and forgot them. if (NumArgs < getNumArgs()) { for (unsigned i = NumArgs, e = getNumArgs(); i != e; ++i) delete getArg(i); this->NumArgs = NumArgs; return; } // Otherwise, we are growing the # arguments. New an bigger argument array. Stmt **NewSubExprs = new Stmt*[NumArgs+1]; // Copy over args. for (unsigned i = 0; i != getNumArgs()+ARGS_START; ++i) NewSubExprs[i] = SubExprs[i]; // Null out new args. for (unsigned i = getNumArgs()+ARGS_START; i != NumArgs+ARGS_START; ++i) NewSubExprs[i] = 0; delete[] SubExprs; SubExprs = NewSubExprs; this->NumArgs = NumArgs; } bool CallExpr::isBuiltinConstantExpr() const { // All simple function calls (e.g. func()) are implicitly cast to pointer to // function. As a result, we try and obtain the DeclRefExpr from the // ImplicitCastExpr. const ImplicitCastExpr *ICE = dyn_cast(getCallee()); if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()). return false; const DeclRefExpr *DRE = dyn_cast(ICE->getSubExpr()); if (!DRE) return false; const FunctionDecl *FDecl = dyn_cast(DRE->getDecl()); if (!FDecl) return false; unsigned builtinID = FDecl->getIdentifier()->getBuiltinID(); if (!builtinID) return false; // We have a builtin that is a constant expression return builtinID == Builtin::BI__builtin___CFStringMakeConstantString || builtinID == Builtin::BI__builtin_classify_type; } bool CallExpr::isBuiltinClassifyType(llvm::APSInt &Result) const { // The following enum mimics gcc's internal "typeclass.h" file. 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 }; Result.setIsSigned(true); // All simple function calls (e.g. func()) are implicitly cast to pointer to // function. As a result, we try and obtain the DeclRefExpr from the // ImplicitCastExpr. const ImplicitCastExpr *ICE = dyn_cast(getCallee()); if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()). return false; const DeclRefExpr *DRE = dyn_cast(ICE->getSubExpr()); if (!DRE) return false; // We have a DeclRefExpr. if (strcmp(DRE->getDecl()->getName(), "__builtin_classify_type") == 0) { // If no argument was supplied, default to "no_type_class". This isn't // ideal, however it's what gcc does. Result = static_cast(no_type_class); if (NumArgs >= 1) { QualType argType = getArg(0)->getType(); if (argType->isVoidType()) Result = void_type_class; else if (argType->isEnumeralType()) Result = enumeral_type_class; else if (argType->isBooleanType()) Result = boolean_type_class; else if (argType->isCharType()) Result = string_type_class; // gcc doesn't appear to use char_type_class else if (argType->isIntegerType()) Result = integer_type_class; else if (argType->isPointerType()) Result = pointer_type_class; else if (argType->isReferenceType()) Result = reference_type_class; else if (argType->isRealType()) Result = real_type_class; else if (argType->isComplexType()) Result = complex_type_class; else if (argType->isFunctionType()) Result = function_type_class; else if (argType->isStructureType()) Result = record_type_class; else if (argType->isUnionType()) Result = union_type_class; else if (argType->isArrayType()) Result = array_type_class; else if (argType->isUnionType()) Result = union_type_class; else // FIXME: offset_type_class, method_type_class, & lang_type_class? assert(0 && "CallExpr::isBuiltinClassifyType(): unimplemented type"); } return true; } return false; } /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it /// corresponds to, e.g. "<<=". const char *BinaryOperator::getOpcodeStr(Opcode Op) { switch (Op) { default: assert(0 && "Unknown binary operator"); case Mul: return "*"; case Div: return "/"; case Rem: return "%"; case Add: return "+"; case Sub: return "-"; case Shl: return "<<"; case Shr: return ">>"; case LT: return "<"; case GT: return ">"; case LE: return "<="; case GE: return ">="; case EQ: return "=="; case NE: return "!="; case And: return "&"; case Xor: return "^"; case Or: return "|"; case LAnd: return "&&"; case LOr: return "||"; case Assign: return "="; case MulAssign: return "*="; case DivAssign: return "/="; case RemAssign: return "%="; case AddAssign: return "+="; case SubAssign: return "-="; case ShlAssign: return "<<="; case ShrAssign: return ">>="; case AndAssign: return "&="; case XorAssign: return "^="; case OrAssign: return "|="; case Comma: return ","; } } InitListExpr::InitListExpr(SourceLocation lbraceloc, Expr **initexprs, unsigned numinits, SourceLocation rbraceloc) : Expr(InitListExprClass, QualType()), LBraceLoc(lbraceloc), RBraceLoc(rbraceloc) { for (unsigned i = 0; i != numinits; i++) InitExprs.push_back(initexprs[i]); } //===----------------------------------------------------------------------===// // Generic Expression Routines //===----------------------------------------------------------------------===// /// hasLocalSideEffect - Return true if this immediate expression has side /// effects, not counting any sub-expressions. bool Expr::hasLocalSideEffect() const { switch (getStmtClass()) { default: return false; case ParenExprClass: return cast(this)->getSubExpr()->hasLocalSideEffect(); case UnaryOperatorClass: { const UnaryOperator *UO = cast(this); switch (UO->getOpcode()) { default: return false; case UnaryOperator::PostInc: case UnaryOperator::PostDec: case UnaryOperator::PreInc: case UnaryOperator::PreDec: return true; // ++/-- case UnaryOperator::Deref: // Dereferencing a volatile pointer is a side-effect. return getType().isVolatileQualified(); case UnaryOperator::Real: case UnaryOperator::Imag: // accessing a piece of a volatile complex is a side-effect. return UO->getSubExpr()->getType().isVolatileQualified(); case UnaryOperator::Extension: return UO->getSubExpr()->hasLocalSideEffect(); } } case BinaryOperatorClass: { const BinaryOperator *BinOp = cast(this); // Consider comma to have side effects if the LHS and RHS both do. if (BinOp->getOpcode() == BinaryOperator::Comma) return BinOp->getLHS()->hasLocalSideEffect() && BinOp->getRHS()->hasLocalSideEffect(); return BinOp->isAssignmentOp(); } case CompoundAssignOperatorClass: return true; case ConditionalOperatorClass: { const ConditionalOperator *Exp = cast(this); return Exp->getCond()->hasLocalSideEffect() || (Exp->getLHS() && Exp->getLHS()->hasLocalSideEffect()) || (Exp->getRHS() && Exp->getRHS()->hasLocalSideEffect()); } case MemberExprClass: case ArraySubscriptExprClass: // If the base pointer or element is to a volatile pointer/field, accessing // if is a side effect. return getType().isVolatileQualified(); case CallExprClass: // TODO: check attributes for pure/const. "void foo() { strlen("bar"); }" // should warn. return true; case ObjCMessageExprClass: return true; case StmtExprClass: { // Statement exprs don't logically have side effects themselves, but are // sometimes used in macros in ways that give them a type that is unused. // For example ({ blah; foo(); }) will end up with a type if foo has a type. // however, if the result of the stmt expr is dead, we don't want to emit a // warning. const CompoundStmt *CS = cast(this)->getSubStmt(); if (!CS->body_empty()) if (const Expr *E = dyn_cast(CS->body_back())) return E->hasLocalSideEffect(); return false; } case ExplicitCastExprClass: case CXXFunctionalCastExprClass: // If this is a cast to void, check the operand. Otherwise, the result of // the cast is unused. if (getType()->isVoidType()) return cast(this)->getSubExpr()->hasLocalSideEffect(); return false; case ImplicitCastExprClass: // Check the operand, since implicit casts are inserted by Sema return cast(this)->getSubExpr()->hasLocalSideEffect(); case CXXDefaultArgExprClass: return cast(this)->getExpr()->hasLocalSideEffect(); } } /// isLvalue - C99 6.3.2.1: an lvalue is an expression with an object type or an /// incomplete type other than void. Nonarray expressions that can be lvalues: /// - name, where name must be a variable /// - e[i] /// - (e), where e must be an lvalue /// - e.name, where e must be an lvalue /// - e->name /// - *e, the type of e cannot be a function type /// - string-constant /// - (__real__ e) and (__imag__ e) where e is an lvalue [GNU extension] /// - reference type [C++ [expr]] /// Expr::isLvalueResult Expr::isLvalue(ASTContext &Ctx) const { // first, check the type (C99 6.3.2.1) if (TR->isFunctionType()) // from isObjectType() return LV_NotObjectType; // Allow qualified void which is an incomplete type other than void (yuck). if (TR->isVoidType() && !Ctx.getCanonicalType(TR).getCVRQualifiers()) return LV_IncompleteVoidType; if (TR->isReferenceType()) // C++ [expr] return LV_Valid; // the type looks fine, now check the expression switch (getStmtClass()) { case StringLiteralClass: // C99 6.5.1p4 return LV_Valid; case ArraySubscriptExprClass: // C99 6.5.3p4 (e1[e2] == (*((e1)+(e2)))) // For vectors, make sure base is an lvalue (i.e. not a function call). if (cast(this)->getBase()->getType()->isVectorType()) return cast(this)->getBase()->isLvalue(Ctx); return LV_Valid; case DeclRefExprClass: { // C99 6.5.1p2 const Decl *RefdDecl = cast(this)->getDecl(); if (isa(RefdDecl) || isa(RefdDecl)) return LV_Valid; break; } case MemberExprClass: { // C99 6.5.2.3p4 const MemberExpr *m = cast(this); return m->isArrow() ? LV_Valid : m->getBase()->isLvalue(Ctx); } case UnaryOperatorClass: if (cast(this)->getOpcode() == UnaryOperator::Deref) return LV_Valid; // C99 6.5.3p4 if (cast(this)->getOpcode() == UnaryOperator::Real || cast(this)->getOpcode() == UnaryOperator::Imag || cast(this)->getOpcode() == UnaryOperator::Extension) return cast(this)->getSubExpr()->isLvalue(Ctx); // GNU. break; case ParenExprClass: // C99 6.5.1p5 return cast(this)->getSubExpr()->isLvalue(Ctx); case CompoundLiteralExprClass: // C99 6.5.2.5p5 return LV_Valid; case ExtVectorElementExprClass: if (cast(this)->containsDuplicateElements()) return LV_DuplicateVectorComponents; return LV_Valid; case ObjCIvarRefExprClass: // ObjC instance variables are lvalues. return LV_Valid; case ObjCPropertyRefExprClass: // FIXME: check if read-only property. return LV_Valid; case PredefinedExprClass: return (cast(this)->getIdentType() == PredefinedExpr::CXXThis ? LV_InvalidExpression : LV_Valid); case CXXDefaultArgExprClass: return cast(this)->getExpr()->isLvalue(Ctx); default: break; } return LV_InvalidExpression; } /// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type, /// does not have an incomplete type, does not have a const-qualified type, and /// if it is a structure or union, does not have any member (including, /// recursively, any member or element of all contained aggregates or unions) /// with a const-qualified type. Expr::isModifiableLvalueResult Expr::isModifiableLvalue(ASTContext &Ctx) const { isLvalueResult lvalResult = isLvalue(Ctx); switch (lvalResult) { case LV_Valid: break; case LV_NotObjectType: return MLV_NotObjectType; case LV_IncompleteVoidType: return MLV_IncompleteVoidType; case LV_DuplicateVectorComponents: return MLV_DuplicateVectorComponents; case LV_InvalidExpression: return MLV_InvalidExpression; } QualType CT = Ctx.getCanonicalType(getType()); if (CT.isConstQualified()) return MLV_ConstQualified; if (CT->isArrayType()) return MLV_ArrayType; if (CT->isIncompleteType()) return MLV_IncompleteType; if (const RecordType *r = CT->getAsRecordType()) { if (r->hasConstFields()) return MLV_ConstQualified; } return MLV_Valid; } /// hasGlobalStorage - Return true if this expression has static storage /// duration. This means that the address of this expression is a link-time /// constant. bool Expr::hasGlobalStorage() const { switch (getStmtClass()) { default: return false; case ParenExprClass: return cast(this)->getSubExpr()->hasGlobalStorage(); case ImplicitCastExprClass: return cast(this)->getSubExpr()->hasGlobalStorage(); case CompoundLiteralExprClass: return cast(this)->isFileScope(); case DeclRefExprClass: { const Decl *D = cast(this)->getDecl(); if (const VarDecl *VD = dyn_cast(D)) return VD->hasGlobalStorage(); if (isa(D)) return true; return false; } case MemberExprClass: { const MemberExpr *M = cast(this); return !M->isArrow() && M->getBase()->hasGlobalStorage(); } case ArraySubscriptExprClass: return cast(this)->getBase()->hasGlobalStorage(); case PredefinedExprClass: return true; case CXXDefaultArgExprClass: return cast(this)->getExpr()->hasGlobalStorage(); } } Expr* Expr::IgnoreParens() { Expr* E = this; while (ParenExpr* P = dyn_cast(E)) E = P->getSubExpr(); return E; } /// IgnoreParenCasts - Ignore parentheses and casts. Strip off any ParenExpr /// or CastExprs or ImplicitCastExprs, returning their operand. Expr *Expr::IgnoreParenCasts() { Expr *E = this; while (true) { if (ParenExpr *P = dyn_cast(E)) E = P->getSubExpr(); else if (CastExpr *P = dyn_cast(E)) E = P->getSubExpr(); else return E; } } bool Expr::isConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const { switch (getStmtClass()) { default: if (Loc) *Loc = getLocStart(); return false; case ParenExprClass: return cast(this)->getSubExpr()->isConstantExpr(Ctx, Loc); case StringLiteralClass: case ObjCStringLiteralClass: case FloatingLiteralClass: case IntegerLiteralClass: case CharacterLiteralClass: case ImaginaryLiteralClass: case TypesCompatibleExprClass: case CXXBoolLiteralExprClass: case AddrLabelExprClass: return true; case CallExprClass: { const CallExpr *CE = cast(this); if (CE->isBuiltinConstantExpr()) return true; if (Loc) *Loc = getLocStart(); return false; } case DeclRefExprClass: { const Decl *D = cast(this)->getDecl(); // Accept address of function. if (isa(D) || isa(D)) return true; if (Loc) *Loc = getLocStart(); if (isa(D)) return TR->isArrayType(); return false; } case CompoundLiteralExprClass: if (Loc) *Loc = getLocStart(); // Allow "(int []){2,4}", since the array will be converted to a pointer. // Allow "(vector type){2,4}" since the elements are all constant. return TR->isArrayType() || TR->isVectorType(); case UnaryOperatorClass: { const UnaryOperator *Exp = cast(this); // C99 6.6p9 if (Exp->getOpcode() == UnaryOperator::AddrOf) { if (!Exp->getSubExpr()->hasGlobalStorage()) { if (Loc) *Loc = getLocStart(); return false; } return true; } // Get the operand value. If this is sizeof/alignof, do not evalute the // operand. This affects C99 6.6p3. if (!Exp->isSizeOfAlignOfOp() && Exp->getOpcode() != UnaryOperator::OffsetOf && !Exp->getSubExpr()->isConstantExpr(Ctx, Loc)) return false; switch (Exp->getOpcode()) { // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. // See C99 6.6p3. default: if (Loc) *Loc = Exp->getOperatorLoc(); return false; case UnaryOperator::Extension: return true; // FIXME: this is wrong. case UnaryOperator::SizeOf: case UnaryOperator::AlignOf: case UnaryOperator::OffsetOf: // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. if (!Exp->getSubExpr()->getType()->isConstantSizeType()) { if (Loc) *Loc = Exp->getOperatorLoc(); return false; } return true; case UnaryOperator::LNot: case UnaryOperator::Plus: case UnaryOperator::Minus: case UnaryOperator::Not: return true; } } case SizeOfAlignOfTypeExprClass: { const SizeOfAlignOfTypeExpr *Exp = cast(this); // alignof always evaluates to a constant. if (Exp->isSizeOf() && !Exp->getArgumentType()->isVoidType() && !Exp->getArgumentType()->isConstantSizeType()) { if (Loc) *Loc = Exp->getOperatorLoc(); return false; } return true; } case BinaryOperatorClass: { const BinaryOperator *Exp = cast(this); // The LHS of a constant expr is always evaluated and needed. if (!Exp->getLHS()->isConstantExpr(Ctx, Loc)) return false; if (!Exp->getRHS()->isConstantExpr(Ctx, Loc)) return false; return true; } case ImplicitCastExprClass: case ExplicitCastExprClass: case CXXFunctionalCastExprClass: { const Expr *SubExpr = cast(this)->getSubExpr(); SourceLocation CastLoc = getLocStart(); if (!SubExpr->isConstantExpr(Ctx, Loc)) { if (Loc) *Loc = SubExpr->getLocStart(); return false; } return true; } case ConditionalOperatorClass: { const ConditionalOperator *Exp = cast(this); if (!Exp->getCond()->isConstantExpr(Ctx, Loc) || // Handle the GNU extension for missing LHS. !(Exp->getLHS() && Exp->getLHS()->isConstantExpr(Ctx, Loc)) || !Exp->getRHS()->isConstantExpr(Ctx, Loc)) return false; return true; } case InitListExprClass: { const InitListExpr *Exp = cast(this); unsigned numInits = Exp->getNumInits(); for (unsigned i = 0; i < numInits; i++) { if (!Exp->getInit(i)->isConstantExpr(Ctx, Loc)) { if (Loc) *Loc = Exp->getInit(i)->getLocStart(); return false; } } return true; } case CXXDefaultArgExprClass: return cast(this)->getExpr()->isConstantExpr(Ctx, Loc); } } /// isIntegerConstantExpr - this recursive routine will test if an expression is /// an integer constant expression. Note: With the introduction of VLA's in /// C99 the result of the sizeof operator is no longer always a constant /// expression. The generalization of the wording to include any subexpression /// that is not evaluated (C99 6.6p3) means that nonconstant subexpressions /// can appear as operands to other operators (e.g. &&, ||, ?:). For instance, /// "0 || f()" can be treated as a constant expression. In C90 this expression, /// occurring in a context requiring a constant, would have been a constraint /// violation. FIXME: This routine currently implements C90 semantics. /// To properly implement C99 semantics this routine will need to evaluate /// expressions involving operators previously mentioned. /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero, /// comma, etc /// /// FIXME: This should ext-warn on overflow during evaluation! ISO C does not /// permit this. This includes things like (int)1e1000 /// /// 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. bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx, SourceLocation *Loc, bool isEvaluated) const { switch (getStmtClass()) { default: if (Loc) *Loc = getLocStart(); return false; case ParenExprClass: return cast(this)->getSubExpr()-> isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated); case IntegerLiteralClass: Result = cast(this)->getValue(); break; case CharacterLiteralClass: { const CharacterLiteral *CL = cast(this); Result.zextOrTrunc(static_cast(Ctx.getTypeSize(getType()))); Result = CL->getValue(); Result.setIsUnsigned(!getType()->isSignedIntegerType()); break; } case TypesCompatibleExprClass: { const TypesCompatibleExpr *TCE = cast(this); Result.zextOrTrunc(static_cast(Ctx.getTypeSize(getType()))); Result = Ctx.typesAreCompatible(TCE->getArgType1(), TCE->getArgType2()); break; } case CallExprClass: { const CallExpr *CE = cast(this); Result.zextOrTrunc(static_cast(Ctx.getTypeSize(getType()))); if (CE->isBuiltinClassifyType(Result)) break; if (Loc) *Loc = getLocStart(); return false; } case DeclRefExprClass: if (const EnumConstantDecl *D = dyn_cast(cast(this)->getDecl())) { Result = D->getInitVal(); break; } if (Loc) *Loc = getLocStart(); return false; case UnaryOperatorClass: { const UnaryOperator *Exp = cast(this); // Get the operand value. If this is sizeof/alignof, do not evalute the // operand. This affects C99 6.6p3. if (!Exp->isSizeOfAlignOfOp() && !Exp->isOffsetOfOp() && !Exp->getSubExpr()->isIntegerConstantExpr(Result, Ctx, Loc,isEvaluated)) return false; switch (Exp->getOpcode()) { // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. // See C99 6.6p3. default: if (Loc) *Loc = Exp->getOperatorLoc(); return false; case UnaryOperator::Extension: return true; // FIXME: this is wrong. case UnaryOperator::SizeOf: case UnaryOperator::AlignOf: // Return the result in the right width. Result.zextOrTrunc(static_cast(Ctx.getTypeSize(getType()))); // sizeof(void) and __alignof__(void) = 1 as a gcc extension. if (Exp->getSubExpr()->getType()->isVoidType()) { Result = 1; break; } // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. if (!Exp->getSubExpr()->getType()->isConstantSizeType()) { if (Loc) *Loc = Exp->getOperatorLoc(); return false; } // Get information about the size or align. if (Exp->getSubExpr()->getType()->isFunctionType()) { // GCC extension: sizeof(function) = 1. Result = Exp->getOpcode() == UnaryOperator::AlignOf ? 4 : 1; } else { unsigned CharSize = Ctx.Target.getCharWidth(); if (Exp->getOpcode() == UnaryOperator::AlignOf) Result = Ctx.getTypeAlign(Exp->getSubExpr()->getType()) / CharSize; else Result = Ctx.getTypeSize(Exp->getSubExpr()->getType()) / CharSize; } break; case UnaryOperator::LNot: { bool Val = Result == 0; Result.zextOrTrunc(static_cast(Ctx.getTypeSize(getType()))); Result = Val; break; } case UnaryOperator::Plus: break; case UnaryOperator::Minus: Result = -Result; break; case UnaryOperator::Not: Result = ~Result; break; case UnaryOperator::OffsetOf: Result = Exp->evaluateOffsetOf(Ctx); } break; } case SizeOfAlignOfTypeExprClass: { const SizeOfAlignOfTypeExpr *Exp = cast(this); // Return the result in the right width. Result.zextOrTrunc(static_cast(Ctx.getTypeSize(getType()))); // sizeof(void) and __alignof__(void) = 1 as a gcc extension. if (Exp->getArgumentType()->isVoidType()) { Result = 1; break; } // alignof always evaluates to a constant, sizeof does if arg is not VLA. if (Exp->isSizeOf() && !Exp->getArgumentType()->isConstantSizeType()) { if (Loc) *Loc = Exp->getOperatorLoc(); return false; } // Get information about the size or align. if (Exp->getArgumentType()->isFunctionType()) { // GCC extension: sizeof(function) = 1. Result = Exp->isSizeOf() ? 1 : 4; } else { unsigned CharSize = Ctx.Target.getCharWidth(); if (Exp->isSizeOf()) Result = Ctx.getTypeSize(Exp->getArgumentType()) / CharSize; else Result = Ctx.getTypeAlign(Exp->getArgumentType()) / CharSize; } break; } case BinaryOperatorClass: { const BinaryOperator *Exp = cast(this); // The LHS of a constant expr is always evaluated and needed. if (!Exp->getLHS()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated)) return false; llvm::APSInt RHS(Result); // The short-circuiting &&/|| operators don't necessarily evaluate their // RHS. Make sure to pass isEvaluated down correctly. if (Exp->isLogicalOp()) { bool RHSEval; if (Exp->getOpcode() == BinaryOperator::LAnd) RHSEval = Result != 0; else { assert(Exp->getOpcode() == BinaryOperator::LOr &&"Unexpected logical"); RHSEval = Result == 0; } if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc, isEvaluated & RHSEval)) return false; } else { if (!Exp->getRHS()->isIntegerConstantExpr(RHS, Ctx, Loc, isEvaluated)) return false; } switch (Exp->getOpcode()) { default: if (Loc) *Loc = getLocStart(); return false; case BinaryOperator::Mul: Result *= RHS; break; case BinaryOperator::Div: if (RHS == 0) { if (!isEvaluated) break; if (Loc) *Loc = getLocStart(); return false; } Result /= RHS; break; case BinaryOperator::Rem: if (RHS == 0) { if (!isEvaluated) break; if (Loc) *Loc = getLocStart(); return false; } Result %= RHS; break; case BinaryOperator::Add: Result += RHS; break; case BinaryOperator::Sub: Result -= RHS; break; case BinaryOperator::Shl: Result <<= static_cast(RHS.getLimitedValue(Result.getBitWidth()-1)); break; case BinaryOperator::Shr: Result >>= static_cast(RHS.getLimitedValue(Result.getBitWidth()-1)); break; case BinaryOperator::LT: Result = Result < RHS; break; case BinaryOperator::GT: Result = Result > RHS; break; case BinaryOperator::LE: Result = Result <= RHS; break; case BinaryOperator::GE: Result = Result >= RHS; break; case BinaryOperator::EQ: Result = Result == RHS; break; case BinaryOperator::NE: Result = Result != RHS; break; case BinaryOperator::And: Result &= RHS; break; case BinaryOperator::Xor: Result ^= RHS; break; case BinaryOperator::Or: Result |= RHS; break; case BinaryOperator::LAnd: Result = Result != 0 && RHS != 0; break; case BinaryOperator::LOr: Result = Result != 0 || RHS != 0; break; case BinaryOperator::Comma: // C99 6.6p3: "shall not contain assignment, ..., or comma operators, // *except* when they are contained within a subexpression that is not // evaluated". Note that Assignment can never happen due to constraints // on the LHS subexpr, so we don't need to check it here. if (isEvaluated) { if (Loc) *Loc = getLocStart(); return false; } // The result of the constant expr is the RHS. Result = RHS; return true; } assert(!Exp->isAssignmentOp() && "LHS can't be a constant expr!"); break; } case ImplicitCastExprClass: case ExplicitCastExprClass: case CXXFunctionalCastExprClass: { const Expr *SubExpr = cast(this)->getSubExpr(); SourceLocation CastLoc = getLocStart(); // C99 6.6p6: shall only convert arithmetic types to integer types. if (!SubExpr->getType()->isArithmeticType() || !getType()->isIntegerType()) { if (Loc) *Loc = SubExpr->getLocStart(); return false; } uint32_t DestWidth = static_cast(Ctx.getTypeSize(getType())); // Handle simple integer->integer casts. if (SubExpr->getType()->isIntegerType()) { if (!SubExpr->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated)) return false; // Figure out if this is a truncate, extend or noop cast. // If the input is signed, do a sign extend, noop, or truncate. if (getType()->isBooleanType()) { // Conversion to bool compares against zero. Result = Result != 0; Result.zextOrTrunc(DestWidth); } else if (SubExpr->getType()->isSignedIntegerType()) Result.sextOrTrunc(DestWidth); else // If the input is unsigned, do a zero extend, noop, or truncate. Result.zextOrTrunc(DestWidth); break; } // Allow floating constants that are the immediate operands of casts or that // are parenthesized. const Expr *Operand = SubExpr; while (const ParenExpr *PE = dyn_cast(Operand)) Operand = PE->getSubExpr(); // If this isn't a floating literal, we can't handle it. const FloatingLiteral *FL = dyn_cast(Operand); if (!FL) { if (Loc) *Loc = Operand->getLocStart(); return false; } // If the destination is boolean, compare against zero. if (getType()->isBooleanType()) { Result = !FL->getValue().isZero(); Result.zextOrTrunc(DestWidth); break; } // Determine whether we are converting to unsigned or signed. bool DestSigned = getType()->isSignedIntegerType(); // TODO: Warn on overflow, but probably not here: isIntegerConstantExpr can // be called multiple times per AST. uint64_t Space[4]; (void)FL->getValue().convertToInteger(Space, DestWidth, DestSigned, llvm::APFloat::rmTowardZero); Result = llvm::APInt(DestWidth, 4, Space); break; } case ConditionalOperatorClass: { const ConditionalOperator *Exp = cast(this); if (!Exp->getCond()->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated)) return false; const Expr *TrueExp = Exp->getLHS(); const Expr *FalseExp = Exp->getRHS(); if (Result == 0) std::swap(TrueExp, FalseExp); // Evaluate the false one first, discard the result. if (FalseExp && !FalseExp->isIntegerConstantExpr(Result, Ctx, Loc, false)) return false; // Evalute the true one, capture the result. if (TrueExp && !TrueExp->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated)) return false; break; } case CXXDefaultArgExprClass: return cast(this) ->isIntegerConstantExpr(Result, Ctx, Loc, isEvaluated); } // Cases that are valid constant exprs fall through to here. Result.setIsUnsigned(getType()->isUnsignedIntegerType()); return true; } /// isNullPointerConstant - C99 6.3.2.3p3 - Return true if this is either an /// integer constant expression with the value zero, or if this is one that is /// cast to void*. bool Expr::isNullPointerConstant(ASTContext &Ctx) const { // Strip off a cast to void*, if it exists. if (const ExplicitCastExpr *CE = dyn_cast(this)) { // Check that it is a cast to void*. if (const PointerType *PT = CE->getType()->getAsPointerType()) { QualType Pointee = PT->getPointeeType(); if (Pointee.getCVRQualifiers() == 0 && Pointee->isVoidType() && // to void* CE->getSubExpr()->getType()->isIntegerType()) // from int. return CE->getSubExpr()->isNullPointerConstant(Ctx); } } else if (const ImplicitCastExpr *ICE = dyn_cast(this)) { // Ignore the ImplicitCastExpr type entirely. return ICE->getSubExpr()->isNullPointerConstant(Ctx); } else if (const ParenExpr *PE = dyn_cast(this)) { // Accept ((void*)0) as a null pointer constant, as many other // implementations do. return PE->getSubExpr()->isNullPointerConstant(Ctx); } else if (const CXXDefaultArgExpr *DefaultArg = dyn_cast(this)) { // See through default argument expressions return DefaultArg->getExpr()->isNullPointerConstant(Ctx); } // This expression must be an integer type. if (!getType()->isIntegerType()) return false; // If we have an integer constant expression, we need to *evaluate* it and // test for the value 0. llvm::APSInt Val(32); return isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0; } unsigned ExtVectorElementExpr::getNumElements() const { if (const VectorType *VT = getType()->getAsVectorType()) return VT->getNumElements(); return 1; } /// containsDuplicateElements - Return true if any element access is repeated. bool ExtVectorElementExpr::containsDuplicateElements() const { const char *compStr = Accessor.getName(); unsigned length = strlen(compStr); for (unsigned i = 0; i < length-1; i++) { const char *s = compStr+i; for (const char c = *s++; *s; s++) if (c == *s) return true; } return false; } /// getEncodedElementAccess - We encode the fields as a llvm ConstantArray. void ExtVectorElementExpr::getEncodedElementAccess( llvm::SmallVectorImpl &Elts) const { const char *compStr = Accessor.getName(); bool isHi = !strcmp(compStr, "hi"); bool isLo = !strcmp(compStr, "lo"); bool isEven = !strcmp(compStr, "e"); bool isOdd = !strcmp(compStr, "o"); for (unsigned i = 0, e = getNumElements(); i != e; ++i) { uint64_t Index; if (isHi) Index = e + i; else if (isLo) Index = i; else if (isEven) Index = 2 * i; else if (isOdd) Index = 2 * i + 1; else Index = ExtVectorType::getAccessorIdx(compStr[i]); Elts.push_back(Index); } } // constructor for instance messages. ObjCMessageExpr::ObjCMessageExpr(Expr *receiver, Selector selInfo, QualType retType, ObjCMethodDecl *mproto, SourceLocation LBrac, SourceLocation RBrac, Expr **ArgExprs, unsigned nargs) : Expr(ObjCMessageExprClass, retType), SelName(selInfo), MethodProto(mproto) { NumArgs = nargs; SubExprs = new Stmt*[NumArgs+1]; SubExprs[RECEIVER] = receiver; if (NumArgs) { for (unsigned i = 0; i != NumArgs; ++i) SubExprs[i+ARGS_START] = static_cast(ArgExprs[i]); } LBracloc = LBrac; RBracloc = RBrac; } // constructor for class messages. // FIXME: clsName should be typed to ObjCInterfaceType ObjCMessageExpr::ObjCMessageExpr(IdentifierInfo *clsName, Selector selInfo, QualType retType, ObjCMethodDecl *mproto, SourceLocation LBrac, SourceLocation RBrac, Expr **ArgExprs, unsigned nargs) : Expr(ObjCMessageExprClass, retType), SelName(selInfo), MethodProto(mproto) { NumArgs = nargs; SubExprs = new Stmt*[NumArgs+1]; SubExprs[RECEIVER] = (Expr*) ((uintptr_t) clsName | IsClsMethDeclUnknown); if (NumArgs) { for (unsigned i = 0; i != NumArgs; ++i) SubExprs[i+ARGS_START] = static_cast(ArgExprs[i]); } LBracloc = LBrac; RBracloc = RBrac; } // constructor for class messages. ObjCMessageExpr::ObjCMessageExpr(ObjCInterfaceDecl *cls, Selector selInfo, QualType retType, ObjCMethodDecl *mproto, SourceLocation LBrac, SourceLocation RBrac, Expr **ArgExprs, unsigned nargs) : Expr(ObjCMessageExprClass, retType), SelName(selInfo), MethodProto(mproto) { NumArgs = nargs; SubExprs = new Stmt*[NumArgs+1]; SubExprs[RECEIVER] = (Expr*) ((uintptr_t) cls | IsClsMethDeclKnown); if (NumArgs) { for (unsigned i = 0; i != NumArgs; ++i) SubExprs[i+ARGS_START] = static_cast(ArgExprs[i]); } LBracloc = LBrac; RBracloc = RBrac; } ObjCMessageExpr::ClassInfo ObjCMessageExpr::getClassInfo() const { uintptr_t x = (uintptr_t) SubExprs[RECEIVER]; switch (x & Flags) { default: assert(false && "Invalid ObjCMessageExpr."); case IsInstMeth: return ClassInfo(0, 0); case IsClsMethDeclUnknown: return ClassInfo(0, (IdentifierInfo*) (x & ~Flags)); case IsClsMethDeclKnown: { ObjCInterfaceDecl* D = (ObjCInterfaceDecl*) (x & ~Flags); return ClassInfo(D, D->getIdentifier()); } } } bool ChooseExpr::isConditionTrue(ASTContext &C) const { return getCond()->getIntegerConstantExprValue(C) != 0; } static int64_t evaluateOffsetOf(ASTContext& C, const Expr *E) { if (const MemberExpr *ME = dyn_cast(E)) { QualType Ty = ME->getBase()->getType(); RecordDecl *RD = Ty->getAsRecordType()->getDecl(); const ASTRecordLayout &RL = C.getASTRecordLayout(RD); FieldDecl *FD = ME->getMemberDecl(); // FIXME: This is linear time. unsigned i = 0, e = 0; for (i = 0, e = RD->getNumMembers(); i != e; i++) { if (RD->getMember(i) == FD) break; } return RL.getFieldOffset(i) + evaluateOffsetOf(C, ME->getBase()); } else if (const ArraySubscriptExpr *ASE = dyn_cast(E)) { const Expr *Base = ASE->getBase(); int64_t size = C.getTypeSize(ASE->getType()); size *= ASE->getIdx()->getIntegerConstantExprValue(C).getSExtValue(); return size + evaluateOffsetOf(C, Base); } else if (isa(E)) return 0; assert(0 && "Unknown offsetof subexpression!"); return 0; } int64_t UnaryOperator::evaluateOffsetOf(ASTContext& C) const { assert(Opc == OffsetOf && "Unary operator not offsetof!"); unsigned CharSize = C.Target.getCharWidth(); return ::evaluateOffsetOf(C, cast(Val)) / CharSize; } //===----------------------------------------------------------------------===// // Child Iterators for iterating over subexpressions/substatements //===----------------------------------------------------------------------===// // DeclRefExpr Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); } Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); } // ObjCIvarRefExpr Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; } Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; } // ObjCPropertyRefExpr Stmt::child_iterator ObjCPropertyRefExpr::child_begin() { return &Base; } Stmt::child_iterator ObjCPropertyRefExpr::child_end() { return &Base+1; } // PredefinedExpr Stmt::child_iterator PredefinedExpr::child_begin() { return child_iterator(); } Stmt::child_iterator PredefinedExpr::child_end() { return child_iterator(); } // IntegerLiteral Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); } Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); } // CharacterLiteral Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator(); } Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); } // FloatingLiteral Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); } Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); } // ImaginaryLiteral Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; } Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; } // StringLiteral Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); } Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); } // ParenExpr Stmt::child_iterator ParenExpr::child_begin() { return &Val; } Stmt::child_iterator ParenExpr::child_end() { return &Val+1; } // UnaryOperator Stmt::child_iterator UnaryOperator::child_begin() { return &Val; } Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; } // SizeOfAlignOfTypeExpr Stmt::child_iterator SizeOfAlignOfTypeExpr::child_begin() { // If the type is a VLA type (and not a typedef), the size expression of the // VLA needs to be treated as an executable expression. if (VariableArrayType* T = dyn_cast(Ty.getTypePtr())) return child_iterator(T); else return child_iterator(); } Stmt::child_iterator SizeOfAlignOfTypeExpr::child_end() { return child_iterator(); } // ArraySubscriptExpr Stmt::child_iterator ArraySubscriptExpr::child_begin() { return &SubExprs[0]; } Stmt::child_iterator ArraySubscriptExpr::child_end() { return &SubExprs[0]+END_EXPR; } // CallExpr Stmt::child_iterator CallExpr::child_begin() { return &SubExprs[0]; } Stmt::child_iterator CallExpr::child_end() { return &SubExprs[0]+NumArgs+ARGS_START; } // MemberExpr Stmt::child_iterator MemberExpr::child_begin() { return &Base; } Stmt::child_iterator MemberExpr::child_end() { return &Base+1; } // ExtVectorElementExpr Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; } Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; } // CompoundLiteralExpr Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; } Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; } // CastExpr Stmt::child_iterator CastExpr::child_begin() { return &Op; } Stmt::child_iterator CastExpr::child_end() { return &Op+1; } // BinaryOperator Stmt::child_iterator BinaryOperator::child_begin() { return &SubExprs[0]; } Stmt::child_iterator BinaryOperator::child_end() { return &SubExprs[0]+END_EXPR; } // ConditionalOperator Stmt::child_iterator ConditionalOperator::child_begin() { return &SubExprs[0]; } Stmt::child_iterator ConditionalOperator::child_end() { return &SubExprs[0]+END_EXPR; } // AddrLabelExpr Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); } Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); } // StmtExpr Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; } Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; } // TypesCompatibleExpr Stmt::child_iterator TypesCompatibleExpr::child_begin() { return child_iterator(); } Stmt::child_iterator TypesCompatibleExpr::child_end() { return child_iterator(); } // ChooseExpr Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; } Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; } // OverloadExpr Stmt::child_iterator OverloadExpr::child_begin() { return &SubExprs[0]; } Stmt::child_iterator OverloadExpr::child_end() { return &SubExprs[0]+NumExprs; } // ShuffleVectorExpr Stmt::child_iterator ShuffleVectorExpr::child_begin() { return &SubExprs[0]; } Stmt::child_iterator ShuffleVectorExpr::child_end() { return &SubExprs[0]+NumExprs; } // VAArgExpr Stmt::child_iterator VAArgExpr::child_begin() { return &Val; } Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; } // InitListExpr Stmt::child_iterator InitListExpr::child_begin() { return InitExprs.size() ? &InitExprs[0] : 0; } Stmt::child_iterator InitListExpr::child_end() { return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0; } // ObjCStringLiteral Stmt::child_iterator ObjCStringLiteral::child_begin() { return child_iterator(); } Stmt::child_iterator ObjCStringLiteral::child_end() { return child_iterator(); } // ObjCEncodeExpr Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); } Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); } // ObjCSelectorExpr Stmt::child_iterator ObjCSelectorExpr::child_begin() { return child_iterator(); } Stmt::child_iterator ObjCSelectorExpr::child_end() { return child_iterator(); } // ObjCProtocolExpr Stmt::child_iterator ObjCProtocolExpr::child_begin() { return child_iterator(); } Stmt::child_iterator ObjCProtocolExpr::child_end() { return child_iterator(); } // ObjCMessageExpr Stmt::child_iterator ObjCMessageExpr::child_begin() { return getReceiver() ? &SubExprs[0] : &SubExprs[0] + ARGS_START; } Stmt::child_iterator ObjCMessageExpr::child_end() { return &SubExprs[0]+ARGS_START+getNumArgs(); }