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Fix collection iterator preview with deleted entries

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We used to assume that we know the remaining entries returned by the
iterator based on the current index. However, that is not accurate,
since entries skipped by the current index could be deleted.

In the new approach, we allocate conservatively and shrink the result.

R=neis@chromium.org

Bug: v8:8433
Change-Id: I38a3004dc3af292daabb454bb76f38d65ef437e8
Reviewed-on: https://chromium-review.googlesource.com/c/1325966
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57360}
This commit is contained in:
Yang Guo 2018-11-08 15:16:17 +01:00 committed by Commit Bot
parent b208c4599d
commit 88f8fe19a8
2 changed files with 241 additions and 25 deletions
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52
src/api.cc
View File

@ -7019,30 +7019,30 @@ i::Handle<i::JSArray> MapAsArray(i::Isolate* isolate, i::Object* table_obj,
i::Factory* factory = isolate->factory();
i::Handle<i::OrderedHashMap> table(i::OrderedHashMap::cast(table_obj),
isolate);
if (offset >= table->NumberOfElements()) return factory->NewJSArray(0);
int length = (table->NumberOfElements() - offset) *
(kind == MapAsArrayKind::kEntries ? 2 : 1);
i::Handle<i::FixedArray> result = factory->NewFixedArray(length);
const bool collect_keys =
kind == MapAsArrayKind::kEntries || kind == MapAsArrayKind::kKeys;
const bool collect_values =
kind == MapAsArrayKind::kEntries || kind == MapAsArrayKind::kValues;
int capacity = table->UsedCapacity();
int max_length =
(capacity - offset) * ((collect_keys && collect_values) ? 2 : 1);
i::Handle<i::FixedArray> result = factory->NewFixedArray(max_length);
int result_index = 0;
{
i::DisallowHeapAllocation no_gc;
int capacity = table->UsedCapacity();
i::Oddball* the_hole = i::ReadOnlyRoots(isolate).the_hole_value();
for (int i = 0; i < capacity; ++i) {
for (int i = offset; i < capacity; ++i) {
i::Object* key = table->KeyAt(i);
if (key == the_hole) continue;
if (offset-- > 0) continue;
if (kind == MapAsArrayKind::kEntries || kind == MapAsArrayKind::kKeys) {
result->set(result_index++, key);
}
if (kind == MapAsArrayKind::kEntries || kind == MapAsArrayKind::kValues) {
result->set(result_index++, table->ValueAt(i));
}
if (collect_keys) result->set(result_index++, key);
if (collect_values) result->set(result_index++, table->ValueAt(i));
}
}
DCHECK_EQ(result_index, result->length());
DCHECK_EQ(result_index, length);
return factory->NewJSArrayWithElements(result, i::PACKED_ELEMENTS, length);
DCHECK_GE(max_length, result_index);
if (result_index == 0) return factory->NewJSArray(0);
result->Shrink(isolate, result_index);
return factory->NewJSArrayWithElements(result, i::PACKED_ELEMENTS,
result_index);
}
} // namespace
@ -7127,24 +7127,26 @@ i::Handle<i::JSArray> SetAsArray(i::Isolate* isolate, i::Object* table_obj,
i::Factory* factory = isolate->factory();
i::Handle<i::OrderedHashSet> table(i::OrderedHashSet::cast(table_obj),
isolate);
int length = table->NumberOfElements() - offset;
if (length <= 0) return factory->NewJSArray(0);
i::Handle<i::FixedArray> result = factory->NewFixedArray(length);
// Elements skipped by |offset| may already be deleted.
int capacity = table->UsedCapacity();
int max_length = capacity - offset;
if (max_length == 0) return factory->NewJSArray(0);
i::Handle<i::FixedArray> result = factory->NewFixedArray(max_length);
int result_index = 0;
{
i::DisallowHeapAllocation no_gc;
int capacity = table->UsedCapacity();
i::Oddball* the_hole = i::ReadOnlyRoots(isolate).the_hole_value();
for (int i = 0; i < capacity; ++i) {
for (int i = offset; i < capacity; ++i) {
i::Object* key = table->KeyAt(i);
if (key == the_hole) continue;
if (offset-- > 0) continue;
result->set(result_index++, key);
}
}
DCHECK_EQ(result_index, result->length());
DCHECK_EQ(result_index, length);
return factory->NewJSArrayWithElements(result, i::PACKED_ELEMENTS, length);
DCHECK_GE(max_length, result_index);
if (result_index == 0) return factory->NewJSArray(0);
result->Shrink(isolate, result_index);
return factory->NewJSArrayWithElements(result, i::PACKED_ELEMENTS,
result_index);
}
} // namespace

214
test/cctest/test-api.cc
View File

@ -28976,3 +28976,217 @@ TEST(MicrotaskContextShouldBeNativeContext) {
isolate->RunMicrotasks();
}
TEST(PreviewSetIteratorEntriesWithDeleted) {
LocalContext env;
v8::HandleScope handle_scope(env->GetIsolate());
v8::Local<v8::Context> context = env.local();
{
// Create set, delete entry, create iterator, preview.
v8::Local<v8::Object> iterator =
CompileRun("var set = new Set([1,2,3]); set.delete(1); set.keys()")
->ToObject(context)
.ToLocalChecked();
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(2, entries->Length());
CHECK_EQ(2, entries->Get(context, 0)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
CHECK_EQ(3, entries->Get(context, 1)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
{
// Create set, create iterator, delete entry, preview.
v8::Local<v8::Object> iterator =
CompileRun("var set = new Set([1,2,3]); set.keys()")
->ToObject(context)
.ToLocalChecked();
CompileRun("set.delete(1);");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(2, entries->Length());
CHECK_EQ(2, entries->Get(context, 0)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
CHECK_EQ(3, entries->Get(context, 1)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
{
// Create set, create iterator, delete entry, iterate, preview.
v8::Local<v8::Object> iterator =
CompileRun("var set = new Set([1,2,3]); var it = set.keys(); it")
->ToObject(context)
.ToLocalChecked();
CompileRun("set.delete(1); it.next();");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(1, entries->Length());
CHECK_EQ(3, entries->Get(context, 0)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
{
// Create set, create iterator, delete entry, iterate until empty, preview.
v8::Local<v8::Object> iterator =
CompileRun("var set = new Set([1,2,3]); var it = set.keys(); it")
->ToObject(context)
.ToLocalChecked();
CompileRun("set.delete(1); it.next(); it.next();");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(0, entries->Length());
}
{
// Create set, create iterator, delete entry, iterate, trigger rehash,
// preview.
v8::Local<v8::Object> iterator =
CompileRun("var set = new Set([1,2,3]); var it = set.keys(); it")
->ToObject(context)
.ToLocalChecked();
CompileRun("set.delete(1); it.next();");
CompileRun("for (var i = 4; i < 20; i++) set.add(i);");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(17, entries->Length());
for (uint32_t i = 0; i < 17; i++) {
CHECK_EQ(i + 3, entries->Get(context, i)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
}
}
TEST(PreviewMapIteratorEntriesWithDeleted) {
LocalContext env;
v8::HandleScope handle_scope(env->GetIsolate());
v8::Local<v8::Context> context = env.local();
{
// Create map, delete entry, create iterator, preview.
v8::Local<v8::Object> iterator = CompileRun(
"var map = new Map();"
"var key = {}; map.set(key, 1);"
"map.set({}, 2); map.set({}, 3);"
"map.delete(key);"
"map.values()")
->ToObject(context)
.ToLocalChecked();
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(2, entries->Length());
CHECK_EQ(2, entries->Get(context, 0)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
CHECK_EQ(3, entries->Get(context, 1)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
{
// Create map, create iterator, delete entry, preview.
v8::Local<v8::Object> iterator = CompileRun(
"var map = new Map();"
"var key = {}; map.set(key, 1);"
"map.set({}, 2); map.set({}, 3);"
"map.values()")
->ToObject(context)
.ToLocalChecked();
CompileRun("map.delete(key);");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(2, entries->Length());
CHECK_EQ(2, entries->Get(context, 0)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
CHECK_EQ(3, entries->Get(context, 1)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
{
// Create map, create iterator, delete entry, iterate, preview.
v8::Local<v8::Object> iterator = CompileRun(
"var map = new Map();"
"var key = {}; map.set(key, 1);"
"map.set({}, 2); map.set({}, 3);"
"var it = map.values(); it")
->ToObject(context)
.ToLocalChecked();
CompileRun("map.delete(key); it.next();");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(1, entries->Length());
CHECK_EQ(3, entries->Get(context, 0)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
{
// Create map, create iterator, delete entry, iterate until empty, preview.
v8::Local<v8::Object> iterator = CompileRun(
"var map = new Map();"
"var key = {}; map.set(key, 1);"
"map.set({}, 2); map.set({}, 3);"
"var it = map.values(); it")
->ToObject(context)
.ToLocalChecked();
CompileRun("map.delete(key); it.next(); it.next();");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(0, entries->Length());
}
{
// Create map, create iterator, delete entry, iterate, trigger rehash,
// preview.
v8::Local<v8::Object> iterator = CompileRun(
"var map = new Map();"
"var key = {}; map.set(key, 1);"
"map.set({}, 2); map.set({}, 3);"
"var it = map.values(); it")
->ToObject(context)
.ToLocalChecked();
CompileRun("map.delete(key); it.next();");
CompileRun("for (var i = 4; i < 20; i++) map.set({}, i);");
bool is_key;
v8::Local<v8::Array> entries =
iterator->PreviewEntries(&is_key).ToLocalChecked();
CHECK(!is_key);
CHECK_EQ(17, entries->Length());
for (uint32_t i = 0; i < 17; i++) {
CHECK_EQ(i + 3, entries->Get(context, i)
.ToLocalChecked()
->Int32Value(context)
.FromJust());
}
}
}