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
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::child_range I = S->children(); I; ++I)
40        M[*I] = 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::child_range I = S->children(); I; ++I) {
86      if (*I) {
87        M[*I] = S;
88        BuildParentMap(M, *I, OVMode);
89      }
90    }
91    break;
92  }
93}
94
95ParentMap::ParentMap(Stmt *S) : Impl(nullptr) {
96  if (S) {
97    MapTy *M = new MapTy();
98    BuildParentMap(*M, S);
99    Impl = M;
100  }
101}
102
103ParentMap::~ParentMap() {
104  delete (MapTy*) Impl;
105}
106
107void ParentMap::addStmt(Stmt* S) {
108  if (S) {
109    BuildParentMap(*(MapTy*) Impl, S);
110  }
111}
112
113void 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
120Stmt* 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
126Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
127  do { S = getParent(S); } while (S && isa<ParenExpr>(S));
128  return S;
129}
130
131Stmt *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
140Stmt *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
148Stmt *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
157bool 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