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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "frontend/DoWhileEmitter.h"

#include "frontend/BytecodeEmitter.h"
#include "frontend/SourceNotes.h"
#include "vm/Opcodes.h"

using namespace js;
using namespace js::frontend;

using mozilla::Maybe;
using mozilla::Nothing;

DoWhileEmitter::DoWhileEmitter(BytecodeEmitter* bce) : bce_(bce) {}

bool DoWhileEmitter::emitBody(const Maybe<uint32_t>& doPos,
                              const Maybe<uint32_t>& bodyPos) {
  MOZ_ASSERT(state_ == State::Start);

  // Ensure that the column of the 'do' is set properly.
  if (doPos) {
    if (!bce_->updateSourceCoordNotes(*doPos)) {
      return false;
    }
  }

  // We need a nop here to make it possible to set a breakpoint on `do`.
  if (!bce_->emit1(JSOP_NOP)) {
    return false;
  }

  // Emit an annotated nop so IonBuilder can recognize the 'do' loop.
  if (!bce_->newSrcNote3(SRC_DO_WHILE, 0, 0, &noteIndex_)) {
    return false;
  }

  loopInfo_.emplace(bce_, StatementKind::DoLoop);

  if (!loopInfo_->emitLoopHead(bce_, bodyPos)) {
    return false;
  }

  if (!loopInfo_->emitLoopEntry(bce_, Nothing())) {
    return false;
  }

#ifdef DEBUG
  state_ = State::Body;
#endif
  return true;
}

bool DoWhileEmitter::emitCond() {
  MOZ_ASSERT(state_ == State::Body);

  if (!loopInfo_->emitContinueTarget(bce_)) {
    return false;
  }

#ifdef DEBUG
  state_ = State::Cond;
#endif
  return true;
}

bool DoWhileEmitter::emitEnd() {
  MOZ_ASSERT(state_ == State::Cond);

  if (!loopInfo_->emitLoopEnd(bce_, JSOP_IFNE)) {
    return false;
  }

  if (!bce_->addTryNote(JSTRY_LOOP, bce_->bytecodeSection().stackDepth(),
                        loopInfo_->headOffset(),
                        loopInfo_->breakTargetOffset())) {
    return false;
  }

  // Update the annotations with the update and back edge positions, for
  // IonBuilder.
  if (!bce_->setSrcNoteOffset(noteIndex_, SrcNote::DoWhile::CondOffset,
                              loopInfo_->continueTargetOffsetFromLoopHead())) {
    return false;
  }
  if (!bce_->setSrcNoteOffset(noteIndex_, SrcNote::DoWhile::BackJumpOffset,
                              loopInfo_->loopEndOffsetFromLoopHead())) {
    return false;
  }

  if (!loopInfo_->patchBreaksAndContinues(bce_)) {
    return false;
  }

  loopInfo_.reset();

#ifdef DEBUG
  state_ = State::End;
#endif
  return true;
}