1 //===--- ScopeInfo.cpp - Information about a semantic context -------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements FunctionScopeInfo and its subclasses, which contain 10 // information about a single function, block, lambda, or method body. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/Sema/ScopeInfo.h" 15 #include "clang/AST/Decl.h" 16 #include "clang/AST/DeclCXX.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 HasDroppedStmt = false; 30 HasOMPDeclareReductionCombiner = false; 31 HasFallthroughStmt = false; 32 HasPotentialAvailabilityViolations = false; 33 ObjCShouldCallSuper = false; 34 ObjCIsDesignatedInit = false; 35 ObjCWarnForNoDesignatedInitChain = false; 36 ObjCIsSecondaryInit = false; 37 ObjCWarnForNoInitDelegation = false; 38 FirstReturnLoc = SourceLocation(); 39 FirstCXXTryLoc = SourceLocation(); 40 FirstSEHTryLoc = SourceLocation(); 41 42 // Coroutine state 43 FirstCoroutineStmtLoc = SourceLocation(); 44 CoroutinePromise = nullptr; 45 CoroutineParameterMoves.clear(); 46 NeedsCoroutineSuspends = true; 47 CoroutineSuspends.first = nullptr; 48 CoroutineSuspends.second = nullptr; 49 50 SwitchStack.clear(); 51 Returns.clear(); 52 ErrorTrap.reset(); 53 PossiblyUnreachableDiags.clear(); 54 WeakObjectUses.clear(); 55 ModifiedNonNullParams.clear(); 56 Blocks.clear(); 57 ByrefBlockVars.clear(); 58 } 59 60 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) { 61 if (PropE->isExplicitProperty()) 62 return PropE->getExplicitProperty(); 63 64 return PropE->getImplicitPropertyGetter(); 65 } 66 67 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy 68 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) { 69 E = E->IgnoreParenCasts(); 70 71 const NamedDecl *D = nullptr; 72 bool IsExact = false; 73 74 switch (E->getStmtClass()) { 75 case Stmt::DeclRefExprClass: 76 D = cast<DeclRefExpr>(E)->getDecl(); 77 IsExact = isa<VarDecl>(D); 78 break; 79 case Stmt::MemberExprClass: { 80 const MemberExpr *ME = cast<MemberExpr>(E); 81 D = ME->getMemberDecl(); 82 IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts()); 83 break; 84 } 85 case Stmt::ObjCIvarRefExprClass: { 86 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E); 87 D = IE->getDecl(); 88 IsExact = IE->getBase()->isObjCSelfExpr(); 89 break; 90 } 91 case Stmt::PseudoObjectExprClass: { 92 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E); 93 const ObjCPropertyRefExpr *BaseProp = 94 dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm()); 95 if (BaseProp) { 96 D = getBestPropertyDecl(BaseProp); 97 98 if (BaseProp->isObjectReceiver()) { 99 const Expr *DoubleBase = BaseProp->getBase(); 100 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase)) 101 DoubleBase = OVE->getSourceExpr(); 102 103 IsExact = DoubleBase->isObjCSelfExpr(); 104 } 105 } 106 break; 107 } 108 default: 109 break; 110 } 111 112 return BaseInfoTy(D, IsExact); 113 } 114 115 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy( 116 const ObjCPropertyRefExpr *PropE) 117 : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) { 118 119 if (PropE->isObjectReceiver()) { 120 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase()); 121 const Expr *E = OVE->getSourceExpr(); 122 Base = getBaseInfo(E); 123 } else if (PropE->isClassReceiver()) { 124 Base.setPointer(PropE->getClassReceiver()); 125 } else { 126 assert(PropE->isSuperReceiver()); 127 } 128 } 129 130 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE, 131 const ObjCPropertyDecl *Prop) 132 : Base(nullptr, true), Property(Prop) { 133 if (BaseE) 134 Base = getBaseInfo(BaseE); 135 // else, this is a message accessing a property on super. 136 } 137 138 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy( 139 const DeclRefExpr *DRE) 140 : Base(nullptr, true), Property(DRE->getDecl()) { 141 assert(isa<VarDecl>(Property)); 142 } 143 144 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy( 145 const ObjCIvarRefExpr *IvarE) 146 : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) { 147 } 148 149 void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg, 150 const ObjCPropertyDecl *Prop) { 151 assert(Msg && Prop); 152 WeakUseVector &Uses = 153 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)]; 154 Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0)); 155 } 156 157 void FunctionScopeInfo::markSafeWeakUse(const Expr *E) { 158 E = E->IgnoreParenCasts(); 159 160 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) { 161 markSafeWeakUse(POE->getSyntacticForm()); 162 return; 163 } 164 165 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) { 166 markSafeWeakUse(Cond->getTrueExpr()); 167 markSafeWeakUse(Cond->getFalseExpr()); 168 return; 169 } 170 171 if (const BinaryConditionalOperator *Cond = 172 dyn_cast<BinaryConditionalOperator>(E)) { 173 markSafeWeakUse(Cond->getCommon()); 174 markSafeWeakUse(Cond->getFalseExpr()); 175 return; 176 } 177 178 // Has this weak object been seen before? 179 FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end(); 180 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) { 181 if (!RefExpr->isObjectReceiver()) 182 return; 183 if (isa<OpaqueValueExpr>(RefExpr->getBase())) 184 Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr)); 185 else { 186 markSafeWeakUse(RefExpr->getBase()); 187 return; 188 } 189 } 190 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E)) 191 Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE)); 192 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 193 if (isa<VarDecl>(DRE->getDecl())) 194 Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE)); 195 } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) { 196 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) { 197 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) { 198 Uses = 199 WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(), 200 Prop)); 201 } 202 } 203 } 204 else 205 return; 206 207 if (Uses == WeakObjectUses.end()) 208 return; 209 210 // Has there been a read from the object using this Expr? 211 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse = 212 llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true)); 213 if (ThisUse == Uses->second.rend()) 214 return; 215 216 ThisUse->markSafe(); 217 } 218 219 bool Capture::isInitCapture() const { 220 // Note that a nested capture of an init-capture is not itself an 221 // init-capture. 222 return !isNested() && isVariableCapture() && getVariable()->isInitCapture(); 223 } 224 225 bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const { 226 for (auto &Cap : Captures) 227 if (Cap.isVLATypeCapture() && Cap.getCapturedVLAType() == VAT) 228 return true; 229 return false; 230 } 231 232 void LambdaScopeInfo::visitPotentialCaptures( 233 llvm::function_ref<void(VarDecl *, Expr *)> Callback) const { 234 for (Expr *E : PotentiallyCapturingExprs) { 235 if (auto *DRE = dyn_cast<DeclRefExpr>(E)) { 236 Callback(cast<VarDecl>(DRE->getFoundDecl()), E); 237 } else if (auto *ME = dyn_cast<MemberExpr>(E)) { 238 Callback(cast<VarDecl>(ME->getMemberDecl()), E); 239 } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) { 240 for (VarDecl *VD : *FP) 241 Callback(VD, E); 242 } else { 243 llvm_unreachable("unexpected expression in potential captures list"); 244 } 245 } 246 } 247 248 FunctionScopeInfo::~FunctionScopeInfo() { } 249 BlockScopeInfo::~BlockScopeInfo() { } 250 CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { } 251