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 if (!S)
32 return;
33
34 switch (S->getStmtClass()) {
35 case Stmt::PseudoObjectExprClass: {
36 assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
37 PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S);
38
39 // If we are rebuilding the map, clear out any existing state.
40 if (M[POE->getSyntacticForm()])
41 for (Stmt *SubStmt : S->children())
42 M[SubStmt] = nullptr;
43
44 M[POE->getSyntacticForm()] = S;
45 BuildParentMap(M, POE->getSyntacticForm(), OV_Transparent);
46
47 for (PseudoObjectExpr::semantics_iterator I = POE->semantics_begin(),
48 E = POE->semantics_end();
49 I != E; ++I) {
50 M[*I] = S;
51 BuildParentMap(M, *I, OV_Opaque);
52 }
53 break;
54 }
55 case Stmt::BinaryConditionalOperatorClass: {
56 assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
57 BinaryConditionalOperator *BCO = cast<BinaryConditionalOperator>(S);
58
59 M[BCO->getCommon()] = S;
60 BuildParentMap(M, BCO->getCommon(), OV_Transparent);
61
62 M[BCO->getCond()] = S;
63 BuildParentMap(M, BCO->getCond(), OV_Opaque);
64
65 M[BCO->getTrueExpr()] = S;
66 BuildParentMap(M, BCO->getTrueExpr(), OV_Opaque);
67
68 M[BCO->getFalseExpr()] = S;
69 BuildParentMap(M, BCO->getFalseExpr(), OV_Transparent);
70
71 break;
72 }
73 case Stmt::OpaqueValueExprClass: {
74 // FIXME: This isn't correct; it assumes that multiple OpaqueValueExprs
75 // share a single source expression, but in the AST a single
76 // OpaqueValueExpr is shared among multiple parent expressions.
77 // The right thing to do is to give the OpaqueValueExpr its syntactic
78 // parent, then not reassign that when traversing the semantic expressions.
79 OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(S);
80 if (OVMode == OV_Transparent || !M[OVE->getSourceExpr()]) {
81 M[OVE->getSourceExpr()] = S;
82 BuildParentMap(M, OVE->getSourceExpr(), OV_Transparent);
83 }
84 break;
85 }
86 default:
87 for (Stmt *SubStmt : S->children()) {
88 if (SubStmt) {
89 M[SubStmt] = S;
90 BuildParentMap(M, SubStmt, OVMode);
91 }
92 }
93 break;
94 }
95 }
96
ParentMap(Stmt * S)97 ParentMap::ParentMap(Stmt *S) : Impl(nullptr) {
98 if (S) {
99 MapTy *M = new MapTy();
100 BuildParentMap(*M, S);
101 Impl = M;
102 }
103 }
104
~ParentMap()105 ParentMap::~ParentMap() {
106 delete (MapTy*) Impl;
107 }
108
addStmt(Stmt * S)109 void ParentMap::addStmt(Stmt* S) {
110 if (S) {
111 BuildParentMap(*(MapTy*) Impl, S);
112 }
113 }
114
setParent(const Stmt * S,const Stmt * Parent)115 void ParentMap::setParent(const Stmt *S, const Stmt *Parent) {
116 assert(S);
117 assert(Parent);
118 MapTy *M = reinterpret_cast<MapTy *>(Impl);
119 M->insert(std::make_pair(const_cast<Stmt *>(S), const_cast<Stmt *>(Parent)));
120 }
121
getParent(Stmt * S) const122 Stmt* ParentMap::getParent(Stmt* S) const {
123 MapTy* M = (MapTy*) Impl;
124 MapTy::iterator I = M->find(S);
125 return I == M->end() ? nullptr : I->second;
126 }
127
getParentIgnoreParens(Stmt * S) const128 Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
129 do { S = getParent(S); } while (S && isa<ParenExpr>(S));
130 return S;
131 }
132
getParentIgnoreParenCasts(Stmt * S) const133 Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {
134 do {
135 S = getParent(S);
136 }
137 while (S && (isa<ParenExpr>(S) || isa<CastExpr>(S)));
138
139 return S;
140 }
141
getParentIgnoreParenImpCasts(Stmt * S) const142 Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {
143 do {
144 S = getParent(S);
145 } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);
146
147 return S;
148 }
149
getOuterParenParent(Stmt * S) const150 Stmt *ParentMap::getOuterParenParent(Stmt *S) const {
151 Stmt *Paren = nullptr;
152 while (isa<ParenExpr>(S)) {
153 Paren = S;
154 S = getParent(S);
155 };
156 return Paren;
157 }
158
isConsumedExpr(Expr * E) const159 bool ParentMap::isConsumedExpr(Expr* E) const {
160 Stmt *P = getParent(E);
161 Stmt *DirectChild = E;
162
163 // Ignore parents that don't guarantee consumption.
164 while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P) ||
165 isa<ExprWithCleanups>(P))) {
166 DirectChild = P;
167 P = getParent(P);
168 }
169
170 if (!P)
171 return false;
172
173 switch (P->getStmtClass()) {
174 default:
175 return isa<Expr>(P);
176 case Stmt::DeclStmtClass:
177 return true;
178 case Stmt::BinaryOperatorClass: {
179 BinaryOperator *BE = cast<BinaryOperator>(P);
180 // If it is a comma, only the right side is consumed.
181 // If it isn't a comma, both sides are consumed.
182 return BE->getOpcode()!=BO_Comma ||DirectChild==BE->getRHS();
183 }
184 case Stmt::ForStmtClass:
185 return DirectChild == cast<ForStmt>(P)->getCond();
186 case Stmt::WhileStmtClass:
187 return DirectChild == cast<WhileStmt>(P)->getCond();
188 case Stmt::DoStmtClass:
189 return DirectChild == cast<DoStmt>(P)->getCond();
190 case Stmt::IfStmtClass:
191 return DirectChild == cast<IfStmt>(P)->getCond();
192 case Stmt::IndirectGotoStmtClass:
193 return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();
194 case Stmt::SwitchStmtClass:
195 return DirectChild == cast<SwitchStmt>(P)->getCond();
196 case Stmt::ReturnStmtClass:
197 return true;
198 }
199 }
200
201