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 ObjCShouldCallSuper = false;
32 ObjCIsDesignatedInit = false;
33 ObjCWarnForNoDesignatedInitChain = false;
34 ObjCIsSecondaryInit = false;
35 ObjCWarnForNoInitDelegation = false;
36
37 SwitchStack.clear();
38 Returns.clear();
39 ErrorTrap.reset();
40 PossiblyUnreachableDiags.clear();
41 WeakObjectUses.clear();
42 ModifiedNonNullParams.clear();
43 }
44
getBestPropertyDecl(const ObjCPropertyRefExpr * PropE)45 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
46 if (PropE->isExplicitProperty())
47 return PropE->getExplicitProperty();
48
49 return PropE->getImplicitPropertyGetter();
50 }
51
52 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
getBaseInfo(const Expr * E)53 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
54 E = E->IgnoreParenCasts();
55
56 const NamedDecl *D = nullptr;
57 bool IsExact = false;
58
59 switch (E->getStmtClass()) {
60 case Stmt::DeclRefExprClass:
61 D = cast<DeclRefExpr>(E)->getDecl();
62 IsExact = isa<VarDecl>(D);
63 break;
64 case Stmt::MemberExprClass: {
65 const MemberExpr *ME = cast<MemberExpr>(E);
66 D = ME->getMemberDecl();
67 IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
68 break;
69 }
70 case Stmt::ObjCIvarRefExprClass: {
71 const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
72 D = IE->getDecl();
73 IsExact = IE->getBase()->isObjCSelfExpr();
74 break;
75 }
76 case Stmt::PseudoObjectExprClass: {
77 const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
78 const ObjCPropertyRefExpr *BaseProp =
79 dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
80 if (BaseProp) {
81 D = getBestPropertyDecl(BaseProp);
82
83 const Expr *DoubleBase = BaseProp->getBase();
84 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
85 DoubleBase = OVE->getSourceExpr();
86
87 IsExact = DoubleBase->isObjCSelfExpr();
88 }
89 break;
90 }
91 default:
92 break;
93 }
94
95 return BaseInfoTy(D, IsExact);
96 }
97
isVLATypeCaptured(const VariableArrayType * VAT) const98 bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
99 RecordDecl *RD = nullptr;
100 if (auto *LSI = dyn_cast<LambdaScopeInfo>(this))
101 RD = LSI->Lambda;
102 else if (auto CRSI = dyn_cast<CapturedRegionScopeInfo>(this))
103 RD = CRSI->TheRecordDecl;
104
105 if (RD)
106 for (auto *FD : RD->fields()) {
107 if (FD->hasCapturedVLAType() && FD->getCapturedVLAType() == VAT)
108 return true;
109 }
110 return false;
111 }
112
WeakObjectProfileTy(const ObjCPropertyRefExpr * PropE)113 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
114 const ObjCPropertyRefExpr *PropE)
115 : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
116
117 if (PropE->isObjectReceiver()) {
118 const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
119 const Expr *E = OVE->getSourceExpr();
120 Base = getBaseInfo(E);
121 } else if (PropE->isClassReceiver()) {
122 Base.setPointer(PropE->getClassReceiver());
123 } else {
124 assert(PropE->isSuperReceiver());
125 }
126 }
127
WeakObjectProfileTy(const Expr * BaseE,const ObjCPropertyDecl * Prop)128 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
129 const ObjCPropertyDecl *Prop)
130 : Base(nullptr, true), Property(Prop) {
131 if (BaseE)
132 Base = getBaseInfo(BaseE);
133 // else, this is a message accessing a property on super.
134 }
135
WeakObjectProfileTy(const DeclRefExpr * DRE)136 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
137 const DeclRefExpr *DRE)
138 : Base(nullptr, true), Property(DRE->getDecl()) {
139 assert(isa<VarDecl>(Property));
140 }
141
WeakObjectProfileTy(const ObjCIvarRefExpr * IvarE)142 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
143 const ObjCIvarRefExpr *IvarE)
144 : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
145 }
146
recordUseOfWeak(const ObjCMessageExpr * Msg,const ObjCPropertyDecl * Prop)147 void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,
148 const ObjCPropertyDecl *Prop) {
149 assert(Msg && Prop);
150 WeakUseVector &Uses =
151 WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
152 Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
153 }
154
markSafeWeakUse(const Expr * E)155 void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
156 E = E->IgnoreParenCasts();
157
158 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
159 markSafeWeakUse(POE->getSyntacticForm());
160 return;
161 }
162
163 if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
164 markSafeWeakUse(Cond->getTrueExpr());
165 markSafeWeakUse(Cond->getFalseExpr());
166 return;
167 }
168
169 if (const BinaryConditionalOperator *Cond =
170 dyn_cast<BinaryConditionalOperator>(E)) {
171 markSafeWeakUse(Cond->getCommon());
172 markSafeWeakUse(Cond->getFalseExpr());
173 return;
174 }
175
176 // Has this weak object been seen before?
177 FunctionScopeInfo::WeakObjectUseMap::iterator Uses;
178 if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
179 if (!RefExpr->isObjectReceiver())
180 return;
181 if (isa<OpaqueValueExpr>(RefExpr->getBase()))
182 Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
183 else {
184 markSafeWeakUse(RefExpr->getBase());
185 return;
186 }
187 }
188 else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
189 Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
190 else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
191 Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
192 else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
193 Uses = WeakObjectUses.end();
194 if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
195 if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
196 Uses =
197 WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
198 Prop));
199 }
200 }
201 }
202 else
203 return;
204
205 if (Uses == WeakObjectUses.end())
206 return;
207
208 // Has there been a read from the object using this Expr?
209 FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
210 std::find(Uses->second.rbegin(), Uses->second.rend(), WeakUseTy(E, true));
211 if (ThisUse == Uses->second.rend())
212 return;
213
214 ThisUse->markSafe();
215 }
216
getPotentialVariableCapture(unsigned Idx,VarDecl * & VD,Expr * & E) const217 void LambdaScopeInfo::getPotentialVariableCapture(unsigned Idx, VarDecl *&VD,
218 Expr *&E) const {
219 assert(Idx < getNumPotentialVariableCaptures() &&
220 "Index of potential capture must be within 0 to less than the "
221 "number of captures!");
222 E = PotentiallyCapturingExprs[Idx];
223 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
224 VD = dyn_cast<VarDecl>(DRE->getFoundDecl());
225 else if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
226 VD = dyn_cast<VarDecl>(ME->getMemberDecl());
227 else
228 llvm_unreachable("Only DeclRefExprs or MemberExprs should be added for "
229 "potential captures");
230 assert(VD);
231 }
232
~FunctionScopeInfo()233 FunctionScopeInfo::~FunctionScopeInfo() { }
~BlockScopeInfo()234 BlockScopeInfo::~BlockScopeInfo() { }
~LambdaScopeInfo()235 LambdaScopeInfo::~LambdaScopeInfo() { }
~CapturedRegionScopeInfo()236 CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }
237