1 //===--- ParentMap.cpp - Mappings from Stmts to their Parents ---*- C++ -*-===//
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 defines the ParentMap class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "clang/AST/ParentMap.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/Expr.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "llvm/ADT/DenseMap.h"
19
20 using namespace clang;
21
22 typedef llvm::DenseMap<Stmt*, Stmt*> MapTy;
23
24 enum OpaqueValueMode {
25 OV_Transparent,
26 OV_Opaque
27 };
28
BuildParentMap(MapTy & M,Stmt * S,OpaqueValueMode OVMode=OV_Transparent)29 static void BuildParentMap(MapTy& M, Stmt* S,
30 OpaqueValueMode OVMode = OV_Transparent) {
31
32 switch (S->getStmtClass()) {
33 case Stmt::PseudoObjectExprClass: {
34 assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
35 PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S);
36
37 // If we are rebuilding the map, clear out any existing state.
38 if (M[POE->getSyntacticForm()])
39 for (Stmt *SubStmt : S->children())
40 M[SubStmt] = nullptr;
41
42 M[POE->getSyntacticForm()] = S;
43 BuildParentMap(M, POE->getSyntacticForm(), OV_Transparent);
44
45 for (PseudoObjectExpr::semantics_iterator I = POE->semantics_begin(),
46 E = POE->semantics_end();
47 I != E; ++I) {
48 M[*I] = S;
49 BuildParentMap(M, *I, OV_Opaque);
50 }
51 break;
52 }
53 case Stmt::BinaryConditionalOperatorClass: {
54 assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
55 BinaryConditionalOperator *BCO = cast<BinaryConditionalOperator>(S);
56
57 M[BCO->getCommon()] = S;
58 BuildParentMap(M, BCO->getCommon(), OV_Transparent);
59
60 M[BCO->getCond()] = S;
61 BuildParentMap(M, BCO->getCond(), OV_Opaque);
62
63 M[BCO->getTrueExpr()] = S;
64 BuildParentMap(M, BCO->getTrueExpr(), OV_Opaque);
65
66 M[BCO->getFalseExpr()] = S;
67 BuildParentMap(M, BCO->getFalseExpr(), OV_Transparent);
68
69 break;
70 }
71 case Stmt::OpaqueValueExprClass: {
72 // FIXME: This isn't correct; it assumes that multiple OpaqueValueExprs
73 // share a single source expression, but in the AST a single
74 // OpaqueValueExpr is shared among multiple parent expressions.
75 // The right thing to do is to give the OpaqueValueExpr its syntactic
76 // parent, then not reassign that when traversing the semantic expressions.
77 OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(S);
78 if (OVMode == OV_Transparent || !M[OVE->getSourceExpr()]) {
79 M[OVE->getSourceExpr()] = S;
80 BuildParentMap(M, OVE->getSourceExpr(), OV_Transparent);
81 }
82 break;
83 }
84 default:
85 for (Stmt *SubStmt : S->children()) {
86 if (SubStmt) {
87 M[SubStmt] = S;
88 BuildParentMap(M, SubStmt, OVMode);
89 }
90 }
91 break;
92 }
93 }
94
ParentMap(Stmt * S)95 ParentMap::ParentMap(Stmt *S) : Impl(nullptr) {
96 if (S) {
97 MapTy *M = new MapTy();
98 BuildParentMap(*M, S);
99 Impl = M;
100 }
101 }
102
~ParentMap()103 ParentMap::~ParentMap() {
104 delete (MapTy*) Impl;
105 }
106
addStmt(Stmt * S)107 void ParentMap::addStmt(Stmt* S) {
108 if (S) {
109 BuildParentMap(*(MapTy*) Impl, S);
110 }
111 }
112
setParent(const Stmt * S,const Stmt * Parent)113 void ParentMap::setParent(const Stmt *S, const Stmt *Parent) {
114 assert(S);
115 assert(Parent);
116 MapTy *M = reinterpret_cast<MapTy *>(Impl);
117 M->insert(std::make_pair(const_cast<Stmt *>(S), const_cast<Stmt *>(Parent)));
118 }
119
getParent(Stmt * S) const120 Stmt* ParentMap::getParent(Stmt* S) const {
121 MapTy* M = (MapTy*) Impl;
122 MapTy::iterator I = M->find(S);
123 return I == M->end() ? nullptr : I->second;
124 }
125
getParentIgnoreParens(Stmt * S) const126 Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
127 do { S = getParent(S); } while (S && isa<ParenExpr>(S));
128 return S;
129 }
130
getParentIgnoreParenCasts(Stmt * S) const131 Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {
132 do {
133 S = getParent(S);
134 }
135 while (S && (isa<ParenExpr>(S) || isa<CastExpr>(S)));
136
137 return S;
138 }
139
getParentIgnoreParenImpCasts(Stmt * S) const140 Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {
141 do {
142 S = getParent(S);
143 } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);
144
145 return S;
146 }
147
getOuterParenParent(Stmt * S) const148 Stmt *ParentMap::getOuterParenParent(Stmt *S) const {
149 Stmt *Paren = nullptr;
150 while (isa<ParenExpr>(S)) {
151 Paren = S;
152 S = getParent(S);
153 };
154 return Paren;
155 }
156
isConsumedExpr(Expr * E) const157 bool ParentMap::isConsumedExpr(Expr* E) const {
158 Stmt *P = getParent(E);
159 Stmt *DirectChild = E;
160
161 // Ignore parents that don't guarantee consumption.
162 while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P) ||
163 isa<ExprWithCleanups>(P))) {
164 DirectChild = P;
165 P = getParent(P);
166 }
167
168 if (!P)
169 return false;
170
171 switch (P->getStmtClass()) {
172 default:
173 return isa<Expr>(P);
174 case Stmt::DeclStmtClass:
175 return true;
176 case Stmt::BinaryOperatorClass: {
177 BinaryOperator *BE = cast<BinaryOperator>(P);
178 // If it is a comma, only the right side is consumed.
179 // If it isn't a comma, both sides are consumed.
180 return BE->getOpcode()!=BO_Comma ||DirectChild==BE->getRHS();
181 }
182 case Stmt::ForStmtClass:
183 return DirectChild == cast<ForStmt>(P)->getCond();
184 case Stmt::WhileStmtClass:
185 return DirectChild == cast<WhileStmt>(P)->getCond();
186 case Stmt::DoStmtClass:
187 return DirectChild == cast<DoStmt>(P)->getCond();
188 case Stmt::IfStmtClass:
189 return DirectChild == cast<IfStmt>(P)->getCond();
190 case Stmt::IndirectGotoStmtClass:
191 return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();
192 case Stmt::SwitchStmtClass:
193 return DirectChild == cast<SwitchStmt>(P)->getCond();
194 case Stmt::ReturnStmtClass:
195 return true;
196 }
197 }
198
199