1 //===--- ScopeInfo.cpp - Information about a semantic context -------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements FunctionScopeInfo and its subclasses, which contain 11 // information about a single function, block, lambda, or method body. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Sema/ScopeInfo.h" 16 #include "clang/AST/Decl.h" 17 #include "clang/AST/DeclObjC.h" 18 #include "clang/AST/Expr.h" 19 #include "clang/AST/ExprCXX.h" 20 #include "clang/AST/ExprObjC.h" 21 22 using namespace clang; 23 using namespace sema; 24 25 void FunctionScopeInfo::Clear() { 26 HasBranchProtectedScope = false; 27 HasBranchIntoScope = false; 28 HasIndirectGoto = false; 29 30 SwitchStack.clear(); 31 Returns.clear(); 32 ErrorTrap.reset(); 33 PossiblyUnreachableDiags.clear(); 34 WeakObjectUses.clear(); 35 } 36 37 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) { 38 if (PropE->isExplicitProperty()) 39 return PropE->getExplicitProperty(); 40 41 return PropE->getImplicitPropertyGetter(); 42 } 43 44 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy 45 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) { 46 E = E->IgnoreParenCasts(); 47 48 const NamedDecl *D = 0; 49 bool IsExact = false; 50 51 switch (E->getStmtClass()) { 52 case Stmt::DeclRefExprClass: 53 D = cast<DeclRefExpr>(E)->getDecl(); 54 IsExact = isa<VarDecl>(D); 55 break; 56 case Stmt::MemberExprClass: { 57 const MemberExpr *ME = cast<MemberExpr>(E); 58 D = ME->getMemberDecl(); 59 IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts()); 60 break; 61 } 62 case Stmt::ObjCIvarRefExprClass: { 63 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E); 64 D = IE->getDecl(); 65 IsExact = IE->getBase()->isObjCSelfExpr(); 66 break; 67 } 68 case Stmt::PseudoObjectExprClass: { 69 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E); 70 const ObjCPropertyRefExpr *BaseProp = 71 dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm()); 72 if (BaseProp) { 73 D = getBestPropertyDecl(BaseProp); 74 75 const Expr *DoubleBase = BaseProp->getBase(); 76 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase)) 77 DoubleBase = OVE->getSourceExpr(); 78 79 IsExact = DoubleBase->isObjCSelfExpr(); 80 } 81 break; 82 } 83 default: 84 break; 85 } 86 87 return BaseInfoTy(D, IsExact); 88 } 89 90 91 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy( 92 const ObjCPropertyRefExpr *PropE) 93 : Base(0, true), Property(getBestPropertyDecl(PropE)) { 94 95 if (PropE->isObjectReceiver()) { 96 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase()); 97 const Expr *E = OVE->getSourceExpr(); 98 Base = getBaseInfo(E); 99 } else if (PropE->isClassReceiver()) { 100 Base.setPointer(PropE->getClassReceiver()); 101 } else { 102 assert(PropE->isSuperReceiver()); 103 } 104 } 105 106 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE, 107 const ObjCPropertyDecl *Prop) 108 : Base(0, true), Property(Prop) { 109 if (BaseE) 110 Base = getBaseInfo(BaseE); 111 // else, this is a message accessing a property on super. 112 } 113 114 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy( 115 const DeclRefExpr *DRE) 116 : Base(0, true), Property(DRE->getDecl()) { 117 assert(isa<VarDecl>(Property)); 118 } 119 120 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy( 121 const ObjCIvarRefExpr *IvarE) 122 : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) { 123 } 124 125 void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg, 126 const ObjCPropertyDecl *Prop) { 127 assert(Msg && Prop); 128 WeakUseVector &Uses = 129 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)]; 130 Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0)); 131 } 132 133 void FunctionScopeInfo::markSafeWeakUse(const Expr *E) { 134 E = E->IgnoreParenCasts(); 135 136 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) { 137 markSafeWeakUse(POE->getSyntacticForm()); 138 return; 139 } 140 141 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) { 142 markSafeWeakUse(Cond->getTrueExpr()); 143 markSafeWeakUse(Cond->getFalseExpr()); 144 return; 145 } 146 147 if (const BinaryConditionalOperator *Cond = 148 dyn_cast<BinaryConditionalOperator>(E)) { 149 markSafeWeakUse(Cond->getCommon()); 150 markSafeWeakUse(Cond->getFalseExpr()); 151 return; 152 } 153 154 // Has this weak object been seen before? 155 FunctionScopeInfo::WeakObjectUseMap::iterator Uses; 156 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) 157 Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr)); 158 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E)) 159 Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE)); 160 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 161 Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE)); 162 else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) { 163 Uses = WeakObjectUses.end(); 164 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) { 165 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) { 166 Uses = 167 WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(), 168 Prop)); 169 } 170 } 171 } 172 else 173 return; 174 175 if (Uses == WeakObjectUses.end()) 176 return; 177 178 // Has there been a read from the object using this Expr? 179 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse = 180 std::find(Uses->second.rbegin(), Uses->second.rend(), WeakUseTy(E, true)); 181 if (ThisUse == Uses->second.rend()) 182 return; 183 184 ThisUse->markSafe(); 185 } 186 187 FunctionScopeInfo::~FunctionScopeInfo() { } 188 BlockScopeInfo::~BlockScopeInfo() { } 189 LambdaScopeInfo::~LambdaScopeInfo() { } 190
