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/DeclObjC.h"
17#include "clang/AST/Expr.h"
18#include "clang/AST/ExprCXX.h"
19#include "clang/AST/ExprObjC.h"
20
21using namespace clang;
22using namespace sema;
23
24void FunctionScopeInfo::Clear() {
25 HasBranchProtectedScope = false;
26 HasBranchIntoScope = false;
27 HasIndirectGoto = false;
28 HasDroppedStmt = false;
29 HasOMPDeclareReductionCombiner = false;
30 HasFallthroughStmt = false;
31 UsesFPIntrin = false;
32 HasPotentialAvailabilityViolations = false;
33 ObjCShouldCallSuper = false;
34 ObjCIsDesignatedInit = false;
35 ObjCWarnForNoDesignatedInitChain = false;
36 ObjCIsSecondaryInit = false;
37 ObjCWarnForNoInitDelegation = false;
38 FirstReturnLoc = SourceLocation();
39 FirstCXXOrObjCTryLoc = SourceLocation();
40 FirstSEHTryLoc = SourceLocation();
41 FirstVLALoc = SourceLocation();
42 FoundImmediateEscalatingExpression = false;
43
44 // Coroutine state
45 FirstCoroutineStmtLoc = SourceLocation();
46 CoroutinePromise = nullptr;
47 CoroutineParameterMoves.clear();
48 NeedsCoroutineSuspends = true;
49 CoroutineSuspends.first = nullptr;
50 CoroutineSuspends.second = nullptr;
51
52 SwitchStack.clear();
53 Returns.clear();
54 ErrorTrap.reset();
55 PossiblyUnreachableDiags.clear();
56 WeakObjectUses.clear();
57 ModifiedNonNullParams.clear();
58 Blocks.clear();
59 ByrefBlockVars.clear();
60 AddrLabels.clear();
61}
62
63static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
64 if (PropE->isExplicitProperty())
65 return PropE->getExplicitProperty();
66
67 return PropE->getImplicitPropertyGetter();
68}
69
70FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
71FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
72 E = E->IgnoreParenCasts();
73
74 const NamedDecl *D = nullptr;
75 bool IsExact = false;
76
77 switch (E->getStmtClass()) {
78 case Stmt::DeclRefExprClass:
79 D = cast<DeclRefExpr>(Val: E)->getDecl();
80 IsExact = isa<VarDecl>(Val: D);
81 break;
82 case Stmt::MemberExprClass: {
83 const MemberExpr *ME = cast<MemberExpr>(Val: E);
84 D = ME->getMemberDecl();
85 IsExact = isa<CXXThisExpr>(Val: ME->getBase()->IgnoreParenImpCasts());
86 break;
87 }
88 case Stmt::ObjCIvarRefExprClass: {
89 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(Val: E);
90 D = IE->getDecl();
91 IsExact = IE->getBase()->isObjCSelfExpr();
92 break;
93 }
94 case Stmt::PseudoObjectExprClass: {
95 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(Val: E);
96 const ObjCPropertyRefExpr *BaseProp =
97 dyn_cast<ObjCPropertyRefExpr>(Val: POE->getSyntacticForm());
98 if (BaseProp) {
99 D = getBestPropertyDecl(PropE: BaseProp);
100
101 if (BaseProp->isObjectReceiver()) {
102 const Expr *DoubleBase = BaseProp->getBase();
103 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Val: DoubleBase))
104 DoubleBase = OVE->getSourceExpr();
105
106 IsExact = DoubleBase->isObjCSelfExpr();
107 }
108 }
109 break;
110 }
111 default:
112 break;
113 }
114
115 return BaseInfoTy(D, IsExact);
116}
117
118FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
119 const ObjCPropertyRefExpr *PropE)
120 : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
121
122 if (PropE->isObjectReceiver()) {
123 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(Val: PropE->getBase());
124 const Expr *E = OVE->getSourceExpr();
125 Base = getBaseInfo(E);
126 } else if (PropE->isClassReceiver()) {
127 Base.setPointer(PropE->getClassReceiver());
128 } else {
129 assert(PropE->isSuperReceiver());
130 }
131}
132
133FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
134 const ObjCPropertyDecl *Prop)
135 : Base(nullptr, true), Property(Prop) {
136 if (BaseE)
137 Base = getBaseInfo(E: BaseE);
138 // else, this is a message accessing a property on super.
139}
140
141FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
142 const DeclRefExpr *DRE)
143 : Base(nullptr, true), Property(DRE->getDecl()) {
144 assert(isa<VarDecl>(Property));
145}
146
147FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
148 const ObjCIvarRefExpr *IvarE)
149 : Base(getBaseInfo(E: IvarE->getBase())), Property(IvarE->getDecl()) {
150}
151
152void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,
153 const ObjCPropertyDecl *Prop) {
154 assert(Msg && Prop);
155 WeakUseVector &Uses =
156 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
157 Uses.push_back(Elt: WeakUseTy(Msg, Msg->getNumArgs() == 0));
158}
159
160void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
161 E = E->IgnoreParenCasts();
162
163 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Val: E)) {
164 markSafeWeakUse(E: POE->getSyntacticForm());
165 return;
166 }
167
168 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(Val: E)) {
169 markSafeWeakUse(E: Cond->getTrueExpr());
170 markSafeWeakUse(E: Cond->getFalseExpr());
171 return;
172 }
173
174 if (const BinaryConditionalOperator *Cond =
175 dyn_cast<BinaryConditionalOperator>(Val: E)) {
176 markSafeWeakUse(E: Cond->getCommon());
177 markSafeWeakUse(E: Cond->getFalseExpr());
178 return;
179 }
180
181 // Has this weak object been seen before?
182 FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();
183 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(Val: E)) {
184 if (!RefExpr->isObjectReceiver())
185 return;
186 if (isa<OpaqueValueExpr>(Val: RefExpr->getBase()))
187 Uses = WeakObjectUses.find(Val: WeakObjectProfileTy(RefExpr));
188 else {
189 markSafeWeakUse(E: RefExpr->getBase());
190 return;
191 }
192 }
193 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(Val: E))
194 Uses = WeakObjectUses.find(Val: WeakObjectProfileTy(IvarE));
195 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: E)) {
196 if (isa<VarDecl>(Val: DRE->getDecl()))
197 Uses = WeakObjectUses.find(Val: WeakObjectProfileTy(DRE));
198 } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(Val: E)) {
199 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
200 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
201 Uses =
202 WeakObjectUses.find(Val: WeakObjectProfileTy(MsgE->getInstanceReceiver(),
203 Prop));
204 }
205 }
206 }
207 else
208 return;
209
210 if (Uses == WeakObjectUses.end())
211 return;
212
213 // Has there been a read from the object using this Expr?
214 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
215 llvm::find(Range: llvm::reverse(C&: Uses->second), Val: WeakUseTy(E, true));
216 if (ThisUse == Uses->second.rend())
217 return;
218
219 ThisUse->markSafe();
220}
221
222bool Capture::isInitCapture() const {
223 // Note that a nested capture of an init-capture is not itself an
224 // init-capture.
225 return !isNested() && isVariableCapture() && getVariable()->isInitCapture();
226}
227
228bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
229 for (auto &Cap : Captures)
230 if (Cap.isVLATypeCapture() && Cap.getCapturedVLAType() == VAT)
231 return true;
232 return false;
233}
234
235void LambdaScopeInfo::visitPotentialCaptures(
236 llvm::function_ref<void(ValueDecl *, Expr *)> Callback) const {
237 for (Expr *E : PotentiallyCapturingExprs) {
238 if (auto *DRE = dyn_cast<DeclRefExpr>(Val: E)) {
239 Callback(cast<ValueDecl>(Val: DRE->getFoundDecl()), E);
240 } else if (auto *ME = dyn_cast<MemberExpr>(Val: E)) {
241 Callback(cast<ValueDecl>(Val: ME->getMemberDecl()), E);
242 } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(Val: E)) {
243 for (ValueDecl *VD : *FP)
244 Callback(VD, E);
245 } else {
246 llvm_unreachable("unexpected expression in potential captures list");
247 }
248 }
249}
250
251bool LambdaScopeInfo::lambdaCaptureShouldBeConst() const {
252 if (ExplicitObjectParameter)
253 return ExplicitObjectParameter->getType()
254 .getNonReferenceType()
255 .isConstQualified();
256 return !Mutable;
257}
258
259FunctionScopeInfo::~FunctionScopeInfo() { }
260BlockScopeInfo::~BlockScopeInfo() { }
261CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }
262