js/src/jit/mips32/Bailouts-mips32.cpp


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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 "jit/mips32/Bailouts-mips32.h"

#include "jit/JitFrames.h"
#include "jit/JitRuntime.h"
#include "jit/ScriptFromCalleeToken.h"
#include "vm/JSContext.h"
#include "vm/Realm.h"

#include "vm/JSScript-inl.h"

using namespace js;
using namespace js::jit;

BailoutFrameInfo::BailoutFrameInfo(const JitActivationIterator& activations,
                                   BailoutStack* bailout)
    : machine_(bailout->machine()) {
  uint8_t* sp = bailout->parentStackPointer();
  framePointer_ = sp + bailout->frameSize();
  topFrameSize_ = framePointer_ - sp;

  JSScript* script =
      ScriptFromCalleeToken(((JitFrameLayout*)framePointer_)->calleeToken());
  JitActivation* activation = activations.activation()->asJit();
  topIonScript_ = script->ionScript();

  attachOnJitActivation(activations);

  if (bailout->frameClass() == FrameSizeClass::None()) {
    snapshotOffset_ = bailout->snapshotOffset();
    return;
  }

  // Compute the snapshot offset from the bailout ID.
  JSRuntime* rt = activation->compartment()->runtimeFromMainThread();
  TrampolinePtr code = rt->jitRuntime()->getBailoutTable(bailout->frameClass());
#ifdef DEBUG
  uint32_t tableSize =
      rt->jitRuntime()->getBailoutTableSize(bailout->frameClass());
#endif
  uintptr_t tableOffset = bailout->tableOffset();
  uintptr_t tableStart = reinterpret_cast<uintptr_t>(code.value);

  MOZ_ASSERT(tableOffset >= tableStart && tableOffset < tableStart + tableSize);
  MOZ_ASSERT((tableOffset - tableStart) % BAILOUT_TABLE_ENTRY_SIZE == 0);

  uint32_t bailoutId =
      ((tableOffset - tableStart) / BAILOUT_TABLE_ENTRY_SIZE) - 1;
  MOZ_ASSERT(bailoutId < BAILOUT_TABLE_SIZE);

  snapshotOffset_ = topIonScript_->bailoutToSnapshot(bailoutId);
}