/* -*- 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/arm/Assembler-arm.h"
#include "jit/Bailouts.h"
#include "jit/JitFrames.h"
#include "jit/JitRuntime.h"
#include "jit/SafepointIndex.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;

namespace js {
namespace jit {

class BailoutStack {
  uintptr_t frameClassId_;
  // This is pushed in the bailout handler. Both entry points into the handler
  // inserts their own value int lr, which is then placed onto the stack along
  // with frameClassId_ above. This should be migrated to ip.
 public:
  union {
    uintptr_t frameSize_;
    uintptr_t tableOffset_;
  };

 protected:  // Silence Clang warning about unused private fields.
  RegisterDump::FPUArray fpregs_;
  RegisterDump::GPRArray regs_;

  uintptr_t snapshotOffset_;
  uintptr_t padding_;

 public:
  FrameSizeClass frameClass() const {
    return FrameSizeClass::FromClass(frameClassId_);
  }
  uintptr_t tableOffset() const {
    MOZ_ASSERT(frameClass() != FrameSizeClass::None());
    return tableOffset_;
  }
  uint32_t frameSize() const {
    if (frameClass() == FrameSizeClass::None()) {
      return frameSize_;
    }
    return frameClass().frameSize();
  }
  MachineState machine() { return MachineState::FromBailout(regs_, fpregs_); }
  SnapshotOffset snapshotOffset() const {
    MOZ_ASSERT(frameClass() == FrameSizeClass::None());
    return snapshotOffset_;
  }
  uint8_t* parentStackPointer() const {
    if (frameClass() == FrameSizeClass::None()) {
      return (uint8_t*)this + sizeof(BailoutStack);
    }
    return (uint8_t*)this + offsetof(BailoutStack, snapshotOffset_);
  }
};

// Make sure the compiler doesn't add extra padding.
static_assert((sizeof(BailoutStack) % 8) == 0,
              "BailoutStack should be 8-byte aligned.");

}  // namespace jit
}  // namespace js

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>(Assembler::BailoutTableStart(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);
}

BailoutFrameInfo::BailoutFrameInfo(const JitActivationIterator& activations,
                                   InvalidationBailoutStack* bailout)
    : machine_(bailout->machine()) {
  framePointer_ = (uint8_t*)bailout->fp();
  topFrameSize_ = framePointer_ - bailout->sp();
  topIonScript_ = bailout->ionScript();
  attachOnJitActivation(activations);

  uint8_t* returnAddressToFp_ = bailout->osiPointReturnAddress();
  const OsiIndex* osiIndex = topIonScript_->getOsiIndex(returnAddressToFp_);
  snapshotOffset_ = osiIndex->snapshotOffset();
}