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 FirstCXXOrObjCTryLoc = SourceLocation();
41 FirstSEHTryLoc = SourceLocation();
42 FirstVLALoc = SourceLocation();
43 FoundImmediateEscalatingExpression = false;
44
45 // Coroutine state
46 FirstCoroutineStmtLoc = SourceLocation();
47 CoroutinePromise = nullptr;
48 CoroutineParameterMoves.clear();
49 NeedsCoroutineSuspends = true;
50 CoroutineSuspends.first = nullptr;
51 CoroutineSuspends.second = nullptr;
52
53 SwitchStack.clear();
54 Returns.clear();
55 ErrorTrap.reset();
56 PossiblyUnreachableDiags.clear();
57 WeakObjectUses.clear();
58 ModifiedNonNullParams.clear();
59 Blocks.clear();
60 ByrefBlockVars.clear();
61 AddrLabels.clear();
62 }
63
getBestPropertyDecl(const ObjCPropertyRefExpr * PropE)64 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
65 if (PropE->isExplicitProperty())
66 return PropE->getExplicitProperty();
67
68 return PropE->getImplicitPropertyGetter();
69 }
70
71 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
getBaseInfo(const Expr * E)72 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
73 E = E->IgnoreParenCasts();
74
75 const NamedDecl *D = nullptr;
76 bool IsExact = false;
77
78 switch (E->getStmtClass()) {
79 case Stmt::DeclRefExprClass:
80 D = cast<DeclRefExpr>(E)->getDecl();
81 IsExact = isa<VarDecl>(D);
82 break;
83 case Stmt::MemberExprClass: {
84 const MemberExpr *ME = cast<MemberExpr>(E);
85 D = ME->getMemberDecl();
86 IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
87 break;
88 }
89 case Stmt::ObjCIvarRefExprClass: {
90 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
91 D = IE->getDecl();
92 IsExact = IE->getBase()->isObjCSelfExpr();
93 break;
94 }
95 case Stmt::PseudoObjectExprClass: {
96 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
97 const ObjCPropertyRefExpr *BaseProp =
98 dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
99 if (BaseProp) {
100 D = getBestPropertyDecl(BaseProp);
101
102 if (BaseProp->isObjectReceiver()) {
103 const Expr *DoubleBase = BaseProp->getBase();
104 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
105 DoubleBase = OVE->getSourceExpr();
106
107 IsExact = DoubleBase->isObjCSelfExpr();
108 }
109 }
110 break;
111 }
112 default:
113 break;
114 }
115
116 return BaseInfoTy(D, IsExact);
117 }
118
WeakObjectProfileTy(const ObjCPropertyRefExpr * PropE)119 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
120 const ObjCPropertyRefExpr *PropE)
121 : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
122
123 if (PropE->isObjectReceiver()) {
124 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
125 const Expr *E = OVE->getSourceExpr();
126 Base = getBaseInfo(E);
127 } else if (PropE->isClassReceiver()) {
128 Base.setPointer(PropE->getClassReceiver());
129 } else {
130 assert(PropE->isSuperReceiver());
131 }
132 }
133
WeakObjectProfileTy(const Expr * BaseE,const ObjCPropertyDecl * Prop)134 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
135 const ObjCPropertyDecl *Prop)
136 : Base(nullptr, true), Property(Prop) {
137 if (BaseE)
138 Base = getBaseInfo(BaseE);
139 // else, this is a message accessing a property on super.
140 }
141
WeakObjectProfileTy(const DeclRefExpr * DRE)142 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
143 const DeclRefExpr *DRE)
144 : Base(nullptr, true), Property(DRE->getDecl()) {
145 assert(isa<VarDecl>(Property));
146 }
147
WeakObjectProfileTy(const ObjCIvarRefExpr * IvarE)148 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
149 const ObjCIvarRefExpr *IvarE)
150 : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
151 }
152
recordUseOfWeak(const ObjCMessageExpr * Msg,const ObjCPropertyDecl * Prop)153 void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,
154 const ObjCPropertyDecl *Prop) {
155 assert(Msg && Prop);
156 WeakUseVector &Uses =
157 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
158 Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
159 }
160
markSafeWeakUse(const Expr * E)161 void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
162 E = E->IgnoreParenCasts();
163
164 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
165 markSafeWeakUse(POE->getSyntacticForm());
166 return;
167 }
168
169 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
170 markSafeWeakUse(Cond->getTrueExpr());
171 markSafeWeakUse(Cond->getFalseExpr());
172 return;
173 }
174
175 if (const BinaryConditionalOperator *Cond =
176 dyn_cast<BinaryConditionalOperator>(E)) {
177 markSafeWeakUse(Cond->getCommon());
178 markSafeWeakUse(Cond->getFalseExpr());
179 return;
180 }
181
182 // Has this weak object been seen before?
183 FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();
184 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
185 if (!RefExpr->isObjectReceiver())
186 return;
187 if (isa<OpaqueValueExpr>(RefExpr->getBase()))
188 Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
189 else {
190 markSafeWeakUse(RefExpr->getBase());
191 return;
192 }
193 }
194 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
195 Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
196 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
197 if (isa<VarDecl>(DRE->getDecl()))
198 Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
199 } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
200 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
201 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
202 Uses =
203 WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
204 Prop));
205 }
206 }
207 }
208 else
209 return;
210
211 if (Uses == WeakObjectUses.end())
212 return;
213
214 // Has there been a read from the object using this Expr?
215 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
216 llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));
217 if (ThisUse == Uses->second.rend())
218 return;
219
220 ThisUse->markSafe();
221 }
222
isInitCapture() const223 bool Capture::isInitCapture() const {
224 // Note that a nested capture of an init-capture is not itself an
225 // init-capture.
226 return !isNested() && isVariableCapture() && getVariable()->isInitCapture();
227 }
228
isVLATypeCaptured(const VariableArrayType * VAT) const229 bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
230 for (auto &Cap : Captures)
231 if (Cap.isVLATypeCapture() && Cap.getCapturedVLAType() == VAT)
232 return true;
233 return false;
234 }
235
visitPotentialCaptures(llvm::function_ref<void (ValueDecl *,Expr *)> Callback) const236 void LambdaScopeInfo::visitPotentialCaptures(
237 llvm::function_ref<void(ValueDecl *, Expr *)> Callback) const {
238 for (Expr *E : PotentiallyCapturingExprs) {
239 if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
240 Callback(cast<ValueDecl>(DRE->getFoundDecl()), E);
241 } else if (auto *ME = dyn_cast<MemberExpr>(E)) {
242 Callback(cast<ValueDecl>(ME->getMemberDecl()), E);
243 } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) {
244 for (ValueDecl *VD : *FP)
245 Callback(VD, E);
246 } else {
247 llvm_unreachable("unexpected expression in potential captures list");
248 }
249 }
250 }
251
lambdaCaptureShouldBeConst() const252 bool LambdaScopeInfo::lambdaCaptureShouldBeConst() const {
253 if (ExplicitObjectParameter)
254 return ExplicitObjectParameter->getType()
255 .getNonReferenceType()
256 .isConstQualified();
257 return !Mutable;
258 }
259
~FunctionScopeInfo()260 FunctionScopeInfo::~FunctionScopeInfo() { }
~BlockScopeInfo()261 BlockScopeInfo::~BlockScopeInfo() { }
~CapturedRegionScopeInfo()262 CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }
263