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/DeclCXX.h"
18 #include "clang/AST/DeclObjC.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/ExprObjC.h"
22
23 using namespace clang;
24 using namespace sema;
25
Clear()26 void FunctionScopeInfo::Clear() {
27 HasBranchProtectedScope = false;
28 HasBranchIntoScope = false;
29 HasIndirectGoto = false;
30 HasDroppedStmt = false;
31 HasOMPDeclareReductionCombiner = false;
32 ObjCShouldCallSuper = false;
33 ObjCIsDesignatedInit = false;
34 ObjCWarnForNoDesignatedInitChain = false;
35 ObjCIsSecondaryInit = false;
36 ObjCWarnForNoInitDelegation = false;
37 FirstReturnLoc = SourceLocation();
38 FirstCXXTryLoc = SourceLocation();
39 FirstSEHTryLoc = SourceLocation();
40
41 SwitchStack.clear();
42 Returns.clear();
43 CoroutinePromise = nullptr;
44 CoroutineStmts.clear();
45 ErrorTrap.reset();
46 PossiblyUnreachableDiags.clear();
47 WeakObjectUses.clear();
48 ModifiedNonNullParams.clear();
49 }
50
getBestPropertyDecl(const ObjCPropertyRefExpr * PropE)51 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
52 if (PropE->isExplicitProperty())
53 return PropE->getExplicitProperty();
54
55 return PropE->getImplicitPropertyGetter();
56 }
57
58 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
getBaseInfo(const Expr * E)59 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
60 E = E->IgnoreParenCasts();
61
62 const NamedDecl *D = nullptr;
63 bool IsExact = false;
64
65 switch (E->getStmtClass()) {
66 case Stmt::DeclRefExprClass:
67 D = cast<DeclRefExpr>(E)->getDecl();
68 IsExact = isa<VarDecl>(D);
69 break;
70 case Stmt::MemberExprClass: {
71 const MemberExpr *ME = cast<MemberExpr>(E);
72 D = ME->getMemberDecl();
73 IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
74 break;
75 }
76 case Stmt::ObjCIvarRefExprClass: {
77 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
78 D = IE->getDecl();
79 IsExact = IE->getBase()->isObjCSelfExpr();
80 break;
81 }
82 case Stmt::PseudoObjectExprClass: {
83 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
84 const ObjCPropertyRefExpr *BaseProp =
85 dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
86 if (BaseProp) {
87 D = getBestPropertyDecl(BaseProp);
88
89 if (BaseProp->isObjectReceiver()) {
90 const Expr *DoubleBase = BaseProp->getBase();
91 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
92 DoubleBase = OVE->getSourceExpr();
93
94 IsExact = DoubleBase->isObjCSelfExpr();
95 }
96 }
97 break;
98 }
99 default:
100 break;
101 }
102
103 return BaseInfoTy(D, IsExact);
104 }
105
isVLATypeCaptured(const VariableArrayType * VAT) const106 bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
107 RecordDecl *RD = nullptr;
108 if (auto *LSI = dyn_cast<LambdaScopeInfo>(this))
109 RD = LSI->Lambda;
110 else if (auto CRSI = dyn_cast<CapturedRegionScopeInfo>(this))
111 RD = CRSI->TheRecordDecl;
112
113 if (RD)
114 for (auto *FD : RD->fields()) {
115 if (FD->hasCapturedVLAType() && FD->getCapturedVLAType() == VAT)
116 return true;
117 }
118 return false;
119 }
120
WeakObjectProfileTy(const ObjCPropertyRefExpr * PropE)121 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
122 const ObjCPropertyRefExpr *PropE)
123 : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
124
125 if (PropE->isObjectReceiver()) {
126 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
127 const Expr *E = OVE->getSourceExpr();
128 Base = getBaseInfo(E);
129 } else if (PropE->isClassReceiver()) {
130 Base.setPointer(PropE->getClassReceiver());
131 } else {
132 assert(PropE->isSuperReceiver());
133 }
134 }
135
WeakObjectProfileTy(const Expr * BaseE,const ObjCPropertyDecl * Prop)136 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
137 const ObjCPropertyDecl *Prop)
138 : Base(nullptr, true), Property(Prop) {
139 if (BaseE)
140 Base = getBaseInfo(BaseE);
141 // else, this is a message accessing a property on super.
142 }
143
WeakObjectProfileTy(const DeclRefExpr * DRE)144 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
145 const DeclRefExpr *DRE)
146 : Base(nullptr, true), Property(DRE->getDecl()) {
147 assert(isa<VarDecl>(Property));
148 }
149
WeakObjectProfileTy(const ObjCIvarRefExpr * IvarE)150 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
151 const ObjCIvarRefExpr *IvarE)
152 : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
153 }
154
recordUseOfWeak(const ObjCMessageExpr * Msg,const ObjCPropertyDecl * Prop)155 void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,
156 const ObjCPropertyDecl *Prop) {
157 assert(Msg && Prop);
158 WeakUseVector &Uses =
159 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
160 Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
161 }
162
markSafeWeakUse(const Expr * E)163 void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
164 E = E->IgnoreParenCasts();
165
166 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
167 markSafeWeakUse(POE->getSyntacticForm());
168 return;
169 }
170
171 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
172 markSafeWeakUse(Cond->getTrueExpr());
173 markSafeWeakUse(Cond->getFalseExpr());
174 return;
175 }
176
177 if (const BinaryConditionalOperator *Cond =
178 dyn_cast<BinaryConditionalOperator>(E)) {
179 markSafeWeakUse(Cond->getCommon());
180 markSafeWeakUse(Cond->getFalseExpr());
181 return;
182 }
183
184 // Has this weak object been seen before?
185 FunctionScopeInfo::WeakObjectUseMap::iterator Uses;
186 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
187 if (!RefExpr->isObjectReceiver())
188 return;
189 if (isa<OpaqueValueExpr>(RefExpr->getBase()))
190 Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
191 else {
192 markSafeWeakUse(RefExpr->getBase());
193 return;
194 }
195 }
196 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
197 Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
198 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
199 Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
200 else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
201 Uses = WeakObjectUses.end();
202 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
203 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
204 Uses =
205 WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
206 Prop));
207 }
208 }
209 }
210 else
211 return;
212
213 if (Uses == WeakObjectUses.end())
214 return;
215
216 // Has there been a read from the object using this Expr?
217 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
218 llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));
219 if (ThisUse == Uses->second.rend())
220 return;
221
222 ThisUse->markSafe();
223 }
224
getPotentialVariableCapture(unsigned Idx,VarDecl * & VD,Expr * & E) const225 void LambdaScopeInfo::getPotentialVariableCapture(unsigned Idx, VarDecl *&VD,
226 Expr *&E) const {
227 assert(Idx < getNumPotentialVariableCaptures() &&
228 "Index of potential capture must be within 0 to less than the "
229 "number of captures!");
230 E = PotentiallyCapturingExprs[Idx];
231 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
232 VD = dyn_cast<VarDecl>(DRE->getFoundDecl());
233 else if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
234 VD = dyn_cast<VarDecl>(ME->getMemberDecl());
235 else
236 llvm_unreachable("Only DeclRefExprs or MemberExprs should be added for "
237 "potential captures");
238 assert(VD);
239 }
240
~FunctionScopeInfo()241 FunctionScopeInfo::~FunctionScopeInfo() { }
~BlockScopeInfo()242 BlockScopeInfo::~BlockScopeInfo() { }
~CapturedRegionScopeInfo()243 CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }
244