SafepointIndex.h - mozsearch

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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/. */

#ifndef jit_SafepointIndex_h

#define jit_SafepointIndex_h

#include "mozilla/Assertions.h"

#include <stdint.h>

#include "jit/IonTypes.h"

namespace js {

namespace jit {

class LSafepoint;

class CodegenSafepointIndex;

// Two-tuple that lets you look up the safepoint entry given the

// displacement of a call instruction within the JIT code.

class SafepointIndex {

  // The displacement is the distance from the first byte of the JIT'd code

  // to the return address (of the call that the safepoint was generated for).

  uint32_t displacement_ = 0;

  // Offset within the safepoint buffer.

  uint32_t safepointOffset_ = 0;

 public:

  inline explicit SafepointIndex(const CodegenSafepointIndex& csi);

  uint32_t displacement() const { return displacement_; }

  uint32_t safepointOffset() const { return safepointOffset_; }

};

class CodegenSafepointIndex {

  uint32_t displacement_ = 0;

  LSafepoint* safepoint_ = nullptr;

 public:

  CodegenSafepointIndex(uint32_t displacement, LSafepoint* safepoint)

      : displacement_(displacement), safepoint_(safepoint) {}

  LSafepoint* safepoint() const { return safepoint_; }

  uint32_t displacement() const { return displacement_; }

  inline SnapshotOffset snapshotOffset() const;

  inline bool hasSnapshotOffset() const;

};

// The OSI point is patched to a call instruction. Therefore, the

// returnPoint for an OSI call is the address immediately following that

// call instruction. The displacement of that point within the assembly

// buffer is the |returnPointDisplacement|.

class OsiIndex {

  uint32_t callPointDisplacement_;

  uint32_t snapshotOffset_;

 public:

  OsiIndex(uint32_t callPointDisplacement, uint32_t snapshotOffset)

      : callPointDisplacement_(callPointDisplacement),

        snapshotOffset_(snapshotOffset) {}

  uint32_t returnPointDisplacement() const;

  uint32_t callPointDisplacement() const { return callPointDisplacement_; }

  uint32_t snapshotOffset() const { return snapshotOffset_; }

};

} /* namespace jit */

} /* namespace js */

#endif /* jit_SafepointIndex_h */