Revert of Always deserialize scope infos for parsing

src/ast/context-slot-cache.cc

Index: src/ast/context-slot-cache.cc
diff --git a/src/ast/context-slot-cache.cc b/src/ast/context-slot-cache.cc
new file mode 100644
index 0000000000000000000000000000000000000000..43bd6d6b19205b9be5f909275e06691f0558b299
--- /dev/null
+++ b/src/ast/context-slot-cache.cc
@@ -0,0 +1,91 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/ast/context-slot-cache.h"
+
+#include <stdlib.h>
+
+#include "src/ast/scopes.h"
+#include "src/bootstrapper.h"
+
+namespace v8 {
+namespace internal {
+
+int ContextSlotCache::Hash(Object* data, String* name) {
+  // Uses only lower 32 bits if pointers are larger.
+  uintptr_t addr_hash =
+      static_cast<uint32_t>(reinterpret_cast<uintptr_t>(data)) >> 2;
+  return static_cast<int>((addr_hash ^ name->Hash()) % kLength);
+}
+
+int ContextSlotCache::Lookup(Object* data, String* name, VariableMode* mode,
+                             InitializationFlag* init_flag,
+                             MaybeAssignedFlag* maybe_assigned_flag) {
+  int index = Hash(data, name);
+  Key& key = keys_[index];
+  if ((key.data == data) && key.name->Equals(name)) {
+    Value result(values_[index]);
+    if (mode != nullptr) *mode = result.mode();
+    if (init_flag != nullptr) *init_flag = result.initialization_flag();
+    if (maybe_assigned_flag != nullptr)
+      *maybe_assigned_flag = result.maybe_assigned_flag();
+    return result.index() + kNotFound;
+  }
+  return kNotFound;
+}
+
+void ContextSlotCache::Update(Handle<Object> data, Handle<String> name,
+                              VariableMode mode, InitializationFlag init_flag,
+                              MaybeAssignedFlag maybe_assigned_flag,
+                              int slot_index) {
+  DisallowHeapAllocation no_gc;
+  Handle<String> internalized_name;
+  DCHECK(slot_index > kNotFound);
+  if (StringTable::InternalizeStringIfExists(name->GetIsolate(), name)
+          .ToHandle(&internalized_name)) {
+    int index = Hash(*data, *internalized_name);
+    Key& key = keys_[index];
+    key.data = *data;
+    key.name = *internalized_name;
+    // Please note value only takes a uint as index.
+    values_[index] =
+        Value(mode, init_flag, maybe_assigned_flag, slot_index - kNotFound)
+            .raw();
+#ifdef DEBUG
+    ValidateEntry(data, name, mode, init_flag, maybe_assigned_flag, slot_index);
+#endif
+  }
+}
+
+void ContextSlotCache::Clear() {
+  for (int index = 0; index < kLength; index++) keys_[index].data = nullptr;
+}
+
+#ifdef DEBUG
+
+void ContextSlotCache::ValidateEntry(Handle<Object> data, Handle<String> name,
+                                     VariableMode mode,
+                                     InitializationFlag init_flag,
+                                     MaybeAssignedFlag maybe_assigned_flag,
+                                     int slot_index) {
+  DisallowHeapAllocation no_gc;
+  Handle<String> internalized_name;
+  if (StringTable::InternalizeStringIfExists(name->GetIsolate(), name)
+          .ToHandle(&internalized_name)) {
+    int index = Hash(*data, *name);
+    Key& key = keys_[index];
+    DCHECK(key.data == *data);
+    DCHECK(key.name->Equals(*name));
+    Value result(values_[index]);
+    DCHECK(result.mode() == mode);
+    DCHECK(result.initialization_flag() == init_flag);
+    DCHECK(result.maybe_assigned_flag() == maybe_assigned_flag);
+    DCHECK(result.index() + kNotFound == slot_index);
+  }
+}
+
+#endif  // DEBUG
+
+}  // namespace internal
+}  // namespace v8