mozjs_sys 0.67.1

System crate for the Mozilla SpiderMonkey JavaScript engine.
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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_BytecodeAnalysis_h
#define jit_BytecodeAnalysis_h

#include "jit/JitAllocPolicy.h"
#include "js/Vector.h"
#include "vm/JSScript.h"

namespace js {
namespace jit {

// Basic information about bytecodes in the script.  Used to help baseline
// compilation.
struct BytecodeInfo {
  static const uint16_t MAX_STACK_DEPTH = 0xffffU;
  uint16_t stackDepth;
  bool initialized : 1;
  bool jumpTarget : 1;

  // If true, this is a JSOP_LOOPENTRY op inside a catch or finally block.
  bool loopEntryInCatchOrFinally : 1;

  void init(unsigned depth) {
    MOZ_ASSERT(depth <= MAX_STACK_DEPTH);
    MOZ_ASSERT_IF(initialized, stackDepth == depth);
    initialized = true;
    stackDepth = depth;
  }
};

class BytecodeAnalysis {
  JSScript* script_;
  Vector<BytecodeInfo, 0, JitAllocPolicy> infos_;

  bool usesEnvironmentChain_;
  bool hasTryFinally_;

 public:
  explicit BytecodeAnalysis(TempAllocator& alloc, JSScript* script);

  MOZ_MUST_USE bool init(TempAllocator& alloc, GSNCache& gsn);

  BytecodeInfo& info(jsbytecode* pc) {
    MOZ_ASSERT(infos_[script_->pcToOffset(pc)].initialized);
    return infos_[script_->pcToOffset(pc)];
  }

  BytecodeInfo* maybeInfo(jsbytecode* pc) {
    if (infos_[script_->pcToOffset(pc)].initialized) {
      return &infos_[script_->pcToOffset(pc)];
    }
    return nullptr;
  }

  bool usesEnvironmentChain() const { return usesEnvironmentChain_; }

  bool hasTryFinally() const { return hasTryFinally_; }
};

}  // namespace jit
}  // namespace js

#endif /* jit_BytecodeAnalysis_h */