InvalidatingFuse.h

Enable keyboard shortcuts

/* -*- 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 vm_InvalidatingFuse_h

#define vm_InvalidatingFuse_h

#include "gc/Barrier.h"

#include "gc/SweepingAPI.h"

#include "vm/GuardFuse.h"

class JSScript;

namespace js {

// [SMDOC] Invalidating Fuses

//

// An invalidating fuse will invalidate a set of dependent IonScripts when the

// fuse is popped. In this way Ion can choose to ignore fuse guarded

// possibilities when doing compilation.

class InvalidatingFuse : public GuardFuse {

 public:

  // Register a script's IonScript as having a dependency on this fuse.

  virtual bool addFuseDependency(JSContext* cx, Handle<JSScript*> script) = 0;

};

// [SMDOC] Invalidating Runtime Fuses

//

// A specialized sublass for handling runtime wide fuses. This provides a

// version of addFuseDependency which records scripts into sets associated with

// their home zone, and invalidates all sets across all zones linked to this

// specific fuse.

class InvalidatingRuntimeFuse : public InvalidatingFuse {

 public:

  virtual bool addFuseDependency(JSContext* cx,

                                 Handle<JSScript*> script) override;

  virtual void popFuse(JSContext* cx) override;

};

// A (weak) set of scripts which are dependent on an associated fuse.

//

// Because it uses JS::WeakCache, GC tracing is taken care of without any need

// for tracing in this class.

class DependentScriptSet {

 public:

  DependentScriptSet(JSContext* cx, InvalidatingFuse* fuse);

  InvalidatingFuse* associatedFuse;

  bool addScriptForFuse(InvalidatingFuse* fuse, Handle<JSScript*> script);

  void invalidateForFuse(JSContext* cx, InvalidatingFuse* fuse);

 private:

  using WeakScriptSet = GCHashSet<WeakHeapPtr<JSScript*>,

                                  StableCellHasher<WeakHeapPtr<JSScript*>>,

                                  js::SystemAllocPolicy>;

  js::WeakCache<WeakScriptSet> weakScripts;

};

class DependentScriptGroup {

  // A dependent script set pairs a fuse with a set of scripts which depend

  // on said fuse; this is a vector of script sets because the expectation for

  // now is that the number of runtime wide invalidating fuses will be small.

  // This will need to be revisited (convert to HashMap?) should that no

  // longer be the case

//

  // Note: This isn't  traced through the zone, but rather through the use

  // of JS::WeakCache.

  Vector<DependentScriptSet, 1, SystemAllocPolicy> dependencies;

 public:

  DependentScriptSet* getOrCreateDependentScriptSet(JSContext* cx,

                                                    InvalidatingFuse* fuse);

  DependentScriptSet* begin() { return dependencies.begin(); }

  DependentScriptSet* end() { return dependencies.end(); }

};

}  // namespace js

#endif  // vm_InvalidatingFuse_h