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-rw-r--r--js/src/frontend/TDZCheckCache.cpp76
1 files changed, 76 insertions, 0 deletions
diff --git a/js/src/frontend/TDZCheckCache.cpp b/js/src/frontend/TDZCheckCache.cpp
new file mode 100644
index 0000000000..779d335759
--- /dev/null
+++ b/js/src/frontend/TDZCheckCache.cpp
@@ -0,0 +1,76 @@
+/* -*- 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/. */
+
+#include "frontend/TDZCheckCache.h"
+
+#include "frontend/BytecodeEmitter.h"
+
+using namespace js;
+using namespace js::frontend;
+
+using mozilla::Maybe;
+using mozilla::Nothing;
+using mozilla::Some;
+
+TDZCheckCache::TDZCheckCache(BytecodeEmitter* bce)
+ : Nestable<TDZCheckCache>(&bce->innermostTDZCheckCache),
+ cache_(bce->fc->nameCollectionPool()) {}
+
+bool TDZCheckCache::ensureCache(BytecodeEmitter* bce) {
+ return cache_ || cache_.acquire(bce->fc);
+}
+
+Maybe<MaybeCheckTDZ> TDZCheckCache::needsTDZCheck(BytecodeEmitter* bce,
+ TaggedParserAtomIndex name) {
+ if (!ensureCache(bce)) {
+ return Nothing();
+ }
+
+ CheckTDZMap::AddPtr p = cache_->lookupForAdd(name);
+ if (p) {
+ return Some(p->value().wrapped);
+ }
+
+ MaybeCheckTDZ rv = CheckTDZ;
+ for (TDZCheckCache* it = enclosing(); it; it = it->enclosing()) {
+ if (it->cache_) {
+ if (CheckTDZMap::Ptr p2 = it->cache_->lookup(name)) {
+ rv = p2->value();
+ break;
+ }
+ }
+ }
+
+ if (!cache_->add(p, name, rv)) {
+ ReportOutOfMemory(bce->fc);
+ return Nothing();
+ }
+
+ return Some(rv);
+}
+
+bool TDZCheckCache::noteTDZCheck(BytecodeEmitter* bce,
+ TaggedParserAtomIndex name,
+ MaybeCheckTDZ check) {
+ if (!ensureCache(bce)) {
+ return false;
+ }
+
+ CheckTDZMap::AddPtr p = cache_->lookupForAdd(name);
+ if (p) {
+ MOZ_ASSERT(
+ !check,
+ "TDZ only needs to be checked once per binding per basic block.");
+ p->value() = check;
+ } else {
+ if (!cache_->add(p, name, check)) {
+ ReportOutOfMemory(bce->fc);
+ return false;
+ }
+ }
+
+ return true;
+}