//===--- ParentMap.cpp - Mappings from Stmts to their Parents ---*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

//  This file defines the ParentMap class.

//

//===----------------------------------------------------------------------===//

#include "clang/AST/ParentMap.h"

#include "clang/AST/Decl.h"

#include "clang/AST/Expr.h"

#include "clang/AST/ExprCXX.h"

#include "clang/AST/StmtObjC.h"

#include "llvm/ADT/DenseMap.h"

using namespace clang;

typedef llvm::DenseMap<Stmt*, Stmt*> MapTy;

enum OpaqueValueMode {

  OV_Transparent,

  OV_Opaque

};

static void BuildParentMap(MapTy& M, Stmt* S,

                           OpaqueValueMode OVMode = OV_Transparent) {

  if (!S)

    return;

  switch (S->getStmtClass()) {

  case Stmt::PseudoObjectExprClass: {

    PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S);

    if (OVMode == OV_Opaque && M[POE->getSyntacticForm()])

      break;

    // If we are rebuilding the map, clear out any existing state.

    if (M[POE->getSyntacticForm()])

      for (Stmt *SubStmt : S->children())

        M[SubStmt] = nullptr;

    M[POE->getSyntacticForm()] = S;

    BuildParentMap(M, POE->getSyntacticForm(), OV_Transparent);

    for (PseudoObjectExpr::semantics_iterator I = POE->semantics_begin(),

                                              E = POE->semantics_end();

         I != E; ++I) {

      M[*I] = S;

      BuildParentMap(M, *I, OV_Opaque);

    }

    break;

  }

  case Stmt::BinaryConditionalOperatorClass: {

    assert(OVMode == OV_Transparent && "Should not appear alongside OVEs");

    BinaryConditionalOperator *BCO = cast<BinaryConditionalOperator>(S);

    M[BCO->getCommon()] = S;

    BuildParentMap(M, BCO->getCommon(), OV_Transparent);

    M[BCO->getCond()] = S;

    BuildParentMap(M, BCO->getCond(), OV_Opaque);

    M[BCO->getTrueExpr()] = S;

    BuildParentMap(M, BCO->getTrueExpr(), OV_Opaque);

    M[BCO->getFalseExpr()] = S;

    BuildParentMap(M, BCO->getFalseExpr(), OV_Transparent);

    break;

  }

  case Stmt::OpaqueValueExprClass: {

    // FIXME: This isn't correct; it assumes that multiple OpaqueValueExprs

    // share a single source expression, but in the AST a single

    // OpaqueValueExpr is shared among multiple parent expressions.

    // The right thing to do is to give the OpaqueValueExpr its syntactic

    // parent, then not reassign that when traversing the semantic expressions.

    OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(S);

    if (OVMode == OV_Transparent || !M[OVE->getSourceExpr()]) {

      M[OVE->getSourceExpr()] = S;

      BuildParentMap(M, OVE->getSourceExpr(), OV_Transparent);

    }

    break;

  }

  case Stmt::CapturedStmtClass:

    for (Stmt *SubStmt : S->children()) {

      if (SubStmt) {

        M[SubStmt] = S;

        BuildParentMap(M, SubStmt, OVMode);

      }

    }

    if (Stmt *SubStmt = cast<CapturedStmt>(S)->getCapturedStmt()) {

      M[SubStmt] = S;

      BuildParentMap(M, SubStmt, OVMode);

    }

    break;

  default:

    for (Stmt *SubStmt : S->children()) {

      if (SubStmt) {

        M[SubStmt] = S;

        BuildParentMap(M, SubStmt, OVMode);

      }

    }

    break;

  }

}

ParentMap::ParentMap(Stmt *S) : Impl(nullptr) {

  if (S) {

    MapTy *M = new MapTy();

    BuildParentMap(*M, S);

    Impl = M;

  }

}

ParentMap::~ParentMap() {

  delete (MapTy*) Impl;

}

void ParentMap::addStmt(Stmt* S) {

  if (S) {

    BuildParentMap(*(MapTy*) Impl, S);

  }

}

void ParentMap::setParent(const Stmt *S, const Stmt *Parent) {

  assert(S);

  assert(Parent);

  MapTy *M = reinterpret_cast<MapTy *>(Impl);

  M->insert(std::make_pair(const_cast<Stmt *>(S), const_cast<Stmt *>(Parent)));

}

Stmt* ParentMap::getParent(Stmt* S) const {

  MapTy* M = (MapTy*) Impl;

  return M->lookup(S);

}

Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {

  do { S = getParent(S); } while (S && isa<ParenExpr>(S));

  return S;

}

Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {

  do {

    S = getParent(S);

  }

  while (S && (isa<ParenExpr>(S) || isa<CastExpr>(S)));

  return S;

}

Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {

  do {

    S = getParent(S);

  } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);

  return S;

}

Stmt *ParentMap::getOuterParenParent(Stmt *S) const {

  Stmt *Paren = nullptr;

  while (isa<ParenExpr>(S)) {

    Paren = S;

    S = getParent(S);

  };

  return Paren;

}

bool ParentMap::isConsumedExpr(Expr* E) const {

  Stmt *P = getParent(E);

  Stmt *DirectChild = E;

  // Ignore parents that don't guarantee consumption.

  while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P) ||

               isa<FullExpr>(P))) {

    DirectChild = P;

    P = getParent(P);

  }

  if (!P)

    return false;

  switch (P->getStmtClass()) {

    default:

      return isa<Expr>(P);

    case Stmt::DeclStmtClass:

      return true;

    case Stmt::BinaryOperatorClass: {

      BinaryOperator *BE = cast<BinaryOperator>(P);

      // If it is a comma, only the right side is consumed.

      // If it isn't a comma, both sides are consumed.

      return BE->getOpcode()!=BO_Comma ||DirectChild==BE->getRHS();

    }

    case Stmt::ForStmtClass:

      return DirectChild == cast<ForStmt>(P)->getCond();

    case Stmt::WhileStmtClass:

      return DirectChild == cast<WhileStmt>(P)->getCond();

    case Stmt::DoStmtClass:

      return DirectChild == cast<DoStmt>(P)->getCond();

    case Stmt::IfStmtClass:

      return DirectChild == cast<IfStmt>(P)->getCond();

    case Stmt::IndirectGotoStmtClass:

      return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();

    case Stmt::SwitchStmtClass:

      return DirectChild == cast<SwitchStmt>(P)->getCond();

    case Stmt::ObjCForCollectionStmtClass:

      return DirectChild == cast<ObjCForCollectionStmt>(P)->getCollection();

    case Stmt::ReturnStmtClass:

      return true;

  }

}