tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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TDZCheckCache.cpp (2000B)

      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 "frontend/TDZCheckCache.h"
      8 
      9 #include "frontend/BytecodeEmitter.h"
     10 
     11 using namespace js;
     12 using namespace js::frontend;
     13 
     14 using mozilla::Maybe;
     15 using mozilla::Nothing;
     16 using mozilla::Some;
     17 
     18 TDZCheckCache::TDZCheckCache(BytecodeEmitter* bce)
     19    : Nestable<TDZCheckCache>(&bce->innermostTDZCheckCache),
     20      cache_(bce->fc->nameCollectionPool()) {}
     21 
     22 bool TDZCheckCache::ensureCache(BytecodeEmitter* bce) {
     23  return cache_ || cache_.acquire(bce->fc);
     24 }
     25 
     26 Maybe<MaybeCheckTDZ> TDZCheckCache::needsTDZCheck(BytecodeEmitter* bce,
     27                                                  TaggedParserAtomIndex name) {
     28  if (!ensureCache(bce)) {
     29    return Nothing();
     30  }
     31 
     32  CheckTDZMap::AddPtr p = cache_->lookupForAdd(name);
     33  if (p) {
     34    return Some(p->value().wrapped);
     35  }
     36 
     37  MaybeCheckTDZ rv = CheckTDZ;
     38  for (TDZCheckCache* it = enclosing(); it; it = it->enclosing()) {
     39    if (it->cache_) {
     40      if (CheckTDZMap::Ptr p2 = it->cache_->lookup(name)) {
     41        rv = p2->value();
     42        break;
     43      }
     44    }
     45  }
     46 
     47  if (!cache_->add(p, name, rv)) {
     48    ReportOutOfMemory(bce->fc);
     49    return Nothing();
     50  }
     51 
     52  return Some(rv);
     53 }
     54 
     55 bool TDZCheckCache::noteTDZCheck(BytecodeEmitter* bce,
     56                                 TaggedParserAtomIndex name,
     57                                 MaybeCheckTDZ check) {
     58  if (!ensureCache(bce)) {
     59    return false;
     60  }
     61 
     62  CheckTDZMap::AddPtr p = cache_->lookupForAdd(name);
     63  if (p) {
     64    MOZ_ASSERT(
     65        !check,
     66        "TDZ only needs to be checked once per binding per basic block.");
     67    p->value() = check;
     68  } else {
     69    if (!cache_->add(p, name, check)) {
     70      ReportOutOfMemory(bce->fc);
     71      return false;
     72    }
     73  }
     74 
     75  return true;
     76 }