deps: cherry-pick 88f8fe1 from upstream V8

Original commit message:

    Fix collection iterator preview with deleted entries

    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}

Refs: https://github.com/v8/v8/commit/88f8fe19a863c6392bd296faf86c06eff2a41bc1

PR-URL: https://github.com/nodejs/node/pull/24514
Refs: https://github.com/nodejs/node/issues/24053
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

2 files changed, 241 insertions, 25 deletions

diff --git a/deps/v8/src/api.cc b/deps/v8/src/api.cc
index 161538638b..64676f06c1 100644
--- a/deps/v8/src/api.cc
+++ b/deps/v8/src/api.cc
@@ -7033,30 +7033,30 @@ 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
@@ -7141,24 +7141,26 @@ 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
 
diff --git a/deps/v8/test/cctest/test-api.cc b/deps/v8/test/cctest/test-api.cc
index 0d92508d24..9bf7870f75 100644
--- a/deps/v8/test/cctest/test-api.cc
+++ b/deps/v8/test/cctest/test-api.cc
@@ -28852,3 +28852,217 @@ TEST(TestGetEmbeddedCodeRange) {
     CHECK_EQ(0, builtins_range.length_in_bytes);
   }
 }
+
+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());
+    }
+  }
+}