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
20using namespace clang;
21
22typedef llvm::DenseMap<Stmt*, Stmt*> MapTy;
23
24enum OpaqueValueMode {
25  OV_Transparent,
26  OV_Opaque
27};
28
29static 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
97ParentMap::ParentMap(Stmt *S) : Impl(nullptr) {
98  if (S) {
99    MapTy *M = new MapTy();
100    BuildParentMap(*M, S);
101    Impl = M;
102  }
103}
104
105ParentMap::~ParentMap() {
106  delete (MapTy*) Impl;
107}
108
109void ParentMap::addStmt(Stmt* S) {
110  if (S) {
111    BuildParentMap(*(MapTy*) Impl, S);
112  }
113}
114
115void 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
122Stmt* 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
128Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
129  do { S = getParent(S); } while (S && isa<ParenExpr>(S));
130  return S;
131}
132
133Stmt *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
142Stmt *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
150Stmt *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
159bool 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