js/src/vm/StencilCache.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "vm/StencilCache.h"
   8
   9 #include "frontend/CompilationStencil.h"
  10 #include "js/experimental/JSStencil.h"
  11 #include "vm/MutexIDs.h"
  12
  13 js::StencilCache::StencilCache()
  14     : cache(js::mutexid::StencilCache), enabled(false) {}
  15
  16 js::StencilCache::AccessKey js::StencilCache::isSourceCached(
  17     ScriptSource* src) {
  18   if (!enabled) {
  19     return cache.noAccess();
  20   }
  21
  22   AccessKey lock(cache.lock());
  23   if (!enabled) {
  24     // As we checked the flag before taking the lock, we have to check again to
  25     // avoid races on the cache manipulation.
  26     return cache.noAccess();
  27   }
  28   if (!lock->watched.has(src)) {
  29     // If the source does not have any cached function, and we do not expect to
  30     // cache any delazification in the future, then skip any cache handling.
  31     return cache.noAccess();
  32   }
  33   return lock;
  34 }
  35
  36 bool js::StencilCache::startCaching(RefPtr<ScriptSource>&& src) {
  37   auto guard = cache.lock();
  38   if (!guard->watched.putNew(std::move(src))) {
  39     return false;
  40   }
  41   enabled = true;
  42   return true;
  43 }
  44
  45 js::frontend::CompilationStencil* js::StencilCache::lookup(
  46     AccessKey& guard, const StencilContext& key) {
  47   auto ptr = guard->functions.lookup(key);
  48   if (!ptr) {
  49     return nullptr;
  50   }
  51
  52   return ptr->value().get();
  53 }
  54
  55 bool js::StencilCache::putNew(AccessKey& guard, const StencilContext& key,
  56                               js::frontend::CompilationStencil* value) {
  57   return guard->functions.putNew(key, value);
  58 }
  59
  60 // Important: This function should not be called within a scope checking for
  61 // isSourceCached, as this would cause a dead-lock.
  62 void js::StencilCache::clearAndDisable() {
  63   auto guard = cache.lock();
  64   guard->functions.clearAndCompact();
  65   guard->watched.clearAndCompact();
  66   enabled = false;
  67 }
  68
  69 /* static */ js::DelazificationCache js::DelazificationCache::singleton;