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
Clear()25 void FunctionScopeInfo::Clear() {
26 HasBranchProtectedScope = false;
27 HasBranchIntoScope = false;
28 HasIndirectGoto = false;
29 HasDroppedStmt = false;
30 HasOMPDeclareReductionCombiner = false;
31 HasFallthroughStmt = false;
32 UsesFPIntrin = false;
33 HasPotentialAvailabilityViolations = false;
34 ObjCShouldCallSuper = false;
35 ObjCIsDesignatedInit = false;
36 ObjCWarnForNoDesignatedInitChain = false;
37 ObjCIsSecondaryInit = false;
38 ObjCWarnForNoInitDelegation = false;
39 FirstReturnLoc = SourceLocation();
40 FirstCXXTryLoc = SourceLocation();
41 FirstSEHTryLoc = SourceLocation();
42
43 // Coroutine state
44 FirstCoroutineStmtLoc = SourceLocation();
45 CoroutinePromise = nullptr;
46 CoroutineParameterMoves.clear();
47 NeedsCoroutineSuspends = true;
48 CoroutineSuspends.first = nullptr;
49 CoroutineSuspends.second = nullptr;
50
51 SwitchStack.clear();
52 Returns.clear();
53 ErrorTrap.reset();
54 PossiblyUnreachableDiags.clear();
55 WeakObjectUses.clear();
56 ModifiedNonNullParams.clear();
57 Blocks.clear();
58 ByrefBlockVars.clear();
59 }
60
getBestPropertyDecl(const ObjCPropertyRefExpr * PropE)61 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
62 if (PropE->isExplicitProperty())
63 return PropE->getExplicitProperty();
64
65 return PropE->getImplicitPropertyGetter();
66 }
67
68 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
getBaseInfo(const Expr * E)69 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
70 E = E->IgnoreParenCasts();
71
72 const NamedDecl *D = nullptr;
73 bool IsExact = false;
74
75 switch (E->getStmtClass()) {
76 case Stmt::DeclRefExprClass:
77 D = cast<DeclRefExpr>(E)->getDecl();
78 IsExact = isa<VarDecl>(D);
79 break;
80 case Stmt::MemberExprClass: {
81 const MemberExpr *ME = cast<MemberExpr>(E);
82 D = ME->getMemberDecl();
83 IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
84 break;
85 }
86 case Stmt::ObjCIvarRefExprClass: {
87 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
88 D = IE->getDecl();
89 IsExact = IE->getBase()->isObjCSelfExpr();
90 break;
91 }
92 case Stmt::PseudoObjectExprClass: {
93 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
94 const ObjCPropertyRefExpr *BaseProp =
95 dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
96 if (BaseProp) {
97 D = getBestPropertyDecl(BaseProp);
98
99 if (BaseProp->isObjectReceiver()) {
100 const Expr *DoubleBase = BaseProp->getBase();
101 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
102 DoubleBase = OVE->getSourceExpr();
103
104 IsExact = DoubleBase->isObjCSelfExpr();
105 }
106 }
107 break;
108 }
109 default:
110 break;
111 }
112
113 return BaseInfoTy(D, IsExact);
114 }
115
WeakObjectProfileTy(const ObjCPropertyRefExpr * PropE)116 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
117 const ObjCPropertyRefExpr *PropE)
118 : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
119
120 if (PropE->isObjectReceiver()) {
121 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
122 const Expr *E = OVE->getSourceExpr();
123 Base = getBaseInfo(E);
124 } else if (PropE->isClassReceiver()) {
125 Base.setPointer(PropE->getClassReceiver());
126 } else {
127 assert(PropE->isSuperReceiver());
128 }
129 }
130
WeakObjectProfileTy(const Expr * BaseE,const ObjCPropertyDecl * Prop)131 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
132 const ObjCPropertyDecl *Prop)
133 : Base(nullptr, true), Property(Prop) {
134 if (BaseE)
135 Base = getBaseInfo(BaseE);
136 // else, this is a message accessing a property on super.
137 }
138
WeakObjectProfileTy(const DeclRefExpr * DRE)139 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
140 const DeclRefExpr *DRE)
141 : Base(nullptr, true), Property(DRE->getDecl()) {
142 assert(isa<VarDecl>(Property));
143 }
144
WeakObjectProfileTy(const ObjCIvarRefExpr * IvarE)145 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
146 const ObjCIvarRefExpr *IvarE)
147 : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
148 }
149
recordUseOfWeak(const ObjCMessageExpr * Msg,const ObjCPropertyDecl * Prop)150 void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,
151 const ObjCPropertyDecl *Prop) {
152 assert(Msg && Prop);
153 WeakUseVector &Uses =
154 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
155 Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
156 }
157
markSafeWeakUse(const Expr * E)158 void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
159 E = E->IgnoreParenCasts();
160
161 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
162 markSafeWeakUse(POE->getSyntacticForm());
163 return;
164 }
165
166 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
167 markSafeWeakUse(Cond->getTrueExpr());
168 markSafeWeakUse(Cond->getFalseExpr());
169 return;
170 }
171
172 if (const BinaryConditionalOperator *Cond =
173 dyn_cast<BinaryConditionalOperator>(E)) {
174 markSafeWeakUse(Cond->getCommon());
175 markSafeWeakUse(Cond->getFalseExpr());
176 return;
177 }
178
179 // Has this weak object been seen before?
180 FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();
181 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
182 if (!RefExpr->isObjectReceiver())
183 return;
184 if (isa<OpaqueValueExpr>(RefExpr->getBase()))
185 Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
186 else {
187 markSafeWeakUse(RefExpr->getBase());
188 return;
189 }
190 }
191 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
192 Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
193 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
194 if (isa<VarDecl>(DRE->getDecl()))
195 Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
196 } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
197 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
198 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
199 Uses =
200 WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
201 Prop));
202 }
203 }
204 }
205 else
206 return;
207
208 if (Uses == WeakObjectUses.end())
209 return;
210
211 // Has there been a read from the object using this Expr?
212 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
213 llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));
214 if (ThisUse == Uses->second.rend())
215 return;
216
217 ThisUse->markSafe();
218 }
219
isInitCapture() const220 bool Capture::isInitCapture() const {
221 // Note that a nested capture of an init-capture is not itself an
222 // init-capture.
223 return !isNested() && isVariableCapture() && getVariable()->isInitCapture();
224 }
225
isVLATypeCaptured(const VariableArrayType * VAT) const226 bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
227 for (auto &Cap : Captures)
228 if (Cap.isVLATypeCapture() && Cap.getCapturedVLAType() == VAT)
229 return true;
230 return false;
231 }
232
visitPotentialCaptures(llvm::function_ref<void (VarDecl *,Expr *)> Callback) const233 void LambdaScopeInfo::visitPotentialCaptures(
234 llvm::function_ref<void(VarDecl *, Expr *)> Callback) const {
235 for (Expr *E : PotentiallyCapturingExprs) {
236 if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
237 Callback(cast<VarDecl>(DRE->getFoundDecl()), E);
238 } else if (auto *ME = dyn_cast<MemberExpr>(E)) {
239 Callback(cast<VarDecl>(ME->getMemberDecl()), E);
240 } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) {
241 for (VarDecl *VD : *FP)
242 Callback(VD, E);
243 } else {
244 llvm_unreachable("unexpected expression in potential captures list");
245 }
246 }
247 }
248
~FunctionScopeInfo()249 FunctionScopeInfo::~FunctionScopeInfo() { }
~BlockScopeInfo()250 BlockScopeInfo::~BlockScopeInfo() { }
~CapturedRegionScopeInfo()251 CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }
252