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      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 "llvm/ADT/DenseMap.h"
     18 
     19 using namespace clang;
     20 
     21 typedef llvm::DenseMap<Stmt*, Stmt*> MapTy;
     22 
     23 enum OpaqueValueMode {
     24   OV_Transparent,
     25   OV_Opaque
     26 };
     27 
     28 static void BuildParentMap(MapTy& M, Stmt* S,
     29                            OpaqueValueMode OVMode = OV_Transparent) {
     30 
     31   switch (S->getStmtClass()) {
     32   case Stmt::PseudoObjectExprClass: {
     33     assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
     34     PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S);
     35 
     36     M[POE->getSyntacticForm()] = S;
     37     BuildParentMap(M, POE->getSyntacticForm(), OV_Transparent);
     38 
     39     for (PseudoObjectExpr::semantics_iterator I = POE->semantics_begin(),
     40                                               E = POE->semantics_end();
     41          I != E; ++I) {
     42       M[*I] = S;
     43       BuildParentMap(M, *I, OV_Opaque);
     44     }
     45     break;
     46   }
     47   case Stmt::BinaryConditionalOperatorClass: {
     48     assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");
     49     BinaryConditionalOperator *BCO = cast<BinaryConditionalOperator>(S);
     50 
     51     M[BCO->getCommon()] = S;
     52     BuildParentMap(M, BCO->getCommon(), OV_Transparent);
     53 
     54     M[BCO->getCond()] = S;
     55     BuildParentMap(M, BCO->getCond(), OV_Opaque);
     56 
     57     M[BCO->getTrueExpr()] = S;
     58     BuildParentMap(M, BCO->getTrueExpr(), OV_Opaque);
     59 
     60     M[BCO->getFalseExpr()] = S;
     61     BuildParentMap(M, BCO->getFalseExpr(), OV_Transparent);
     62 
     63     break;
     64   }
     65   case Stmt::OpaqueValueExprClass:
     66     if (OVMode == OV_Transparent) {
     67       OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(S);
     68       M[OVE->getSourceExpr()] = S;
     69       BuildParentMap(M, OVE->getSourceExpr(), OV_Transparent);
     70     }
     71     break;
     72   default:
     73     for (Stmt::child_range I = S->children(); I; ++I) {
     74       if (*I) {
     75         M[*I] = S;
     76         BuildParentMap(M, *I, OVMode);
     77       }
     78     }
     79     break;
     80   }
     81 }
     82 
     83 ParentMap::ParentMap(Stmt* S) : Impl(0) {
     84   if (S) {
     85     MapTy *M = new MapTy();
     86     BuildParentMap(*M, S);
     87     Impl = M;
     88   }
     89 }
     90 
     91 ParentMap::~ParentMap() {
     92   delete (MapTy*) Impl;
     93 }
     94 
     95 void ParentMap::addStmt(Stmt* S) {
     96   if (S) {
     97     BuildParentMap(*(MapTy*) Impl, S);
     98   }
     99 }
    100 
    101 Stmt* ParentMap::getParent(Stmt* S) const {
    102   MapTy* M = (MapTy*) Impl;
    103   MapTy::iterator I = M->find(S);
    104   return I == M->end() ? 0 : I->second;
    105 }
    106 
    107 Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
    108   do { S = getParent(S); } while (S && isa<ParenExpr>(S));
    109   return S;
    110 }
    111 
    112 Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {
    113   do {
    114     S = getParent(S);
    115   }
    116   while (S && (isa<ParenExpr>(S) || isa<CastExpr>(S)));
    117 
    118   return S;
    119 }
    120 
    121 Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {
    122   do {
    123     S = getParent(S);
    124   } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);
    125 
    126   return S;
    127 }
    128 
    129 Stmt *ParentMap::getOuterParenParent(Stmt *S) const {
    130   Stmt *Paren = 0;
    131   while (isa<ParenExpr>(S)) {
    132     Paren = S;
    133     S = getParent(S);
    134   };
    135   return Paren;
    136 }
    137 
    138 bool ParentMap::isConsumedExpr(Expr* E) const {
    139   Stmt *P = getParent(E);
    140   Stmt *DirectChild = E;
    141 
    142   // Ignore parents that are parentheses or casts.
    143   while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P))) {
    144     DirectChild = P;
    145     P = getParent(P);
    146   }
    147 
    148   if (!P)
    149     return false;
    150 
    151   switch (P->getStmtClass()) {
    152     default:
    153       return isa<Expr>(P);
    154     case Stmt::DeclStmtClass:
    155       return true;
    156     case Stmt::BinaryOperatorClass: {
    157       BinaryOperator *BE = cast<BinaryOperator>(P);
    158       // If it is a comma, only the right side is consumed.
    159       // If it isn't a comma, both sides are consumed.
    160       return BE->getOpcode()!=BO_Comma ||DirectChild==BE->getRHS();
    161     }
    162     case Stmt::ForStmtClass:
    163       return DirectChild == cast<ForStmt>(P)->getCond();
    164     case Stmt::WhileStmtClass:
    165       return DirectChild == cast<WhileStmt>(P)->getCond();
    166     case Stmt::DoStmtClass:
    167       return DirectChild == cast<DoStmt>(P)->getCond();
    168     case Stmt::IfStmtClass:
    169       return DirectChild == cast<IfStmt>(P)->getCond();
    170     case Stmt::IndirectGotoStmtClass:
    171       return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();
    172     case Stmt::SwitchStmtClass:
    173       return DirectChild == cast<SwitchStmt>(P)->getCond();
    174     case Stmt::ReturnStmtClass:
    175       return true;
    176   }
    177 }
    178 
    179