Serializer: cache hashmaps on the isolate.

src/isolate.h

 // Copyright 2012 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.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <queue>
 #include "include/v8-debug.h"
 #include "src/allocation.h"
@@ skipping 358 matching lines @@
   /* To distinguish the function templates, so that we can find them in the */ \
   /* function cache of the native context. */                                  \
   V(int, next_serial_number, 0)                                                \
   V(ExternalReferenceRedirectorPointer*, external_reference_redirector, NULL)  \
   /* Part of the state of liveedit. */                                         \
   V(FunctionInfoListener*, active_function_info_listener, NULL)                \
   /* State for Relocatable. */                                                 \
   V(Relocatable*, relocatable_top, NULL)                                       \
   V(DebugObjectCache*, string_stream_debug_object_cache, NULL)                 \
   V(Object*, string_stream_current_security_token, NULL)                       \
-  /* Serializer state. */                                                      \
   V(ExternalReferenceTable*, external_reference_table, NULL)                   \
+  V(HashMap*, external_reference_map, NULL)                                    \
+  V(HashMap*, root_index_map, NULL)                                            \
   V(int, pending_microtask_count, 0)                                           \
   V(bool, autorun_microtasks, true)                                            \
   V(HStatistics*, hstatistics, NULL)                                           \
   V(CompilationStatistics*, turbo_statistics, NULL)                            \
   V(HTracer*, htracer, NULL)                                                   \
   V(CodeTracer*, code_tracer, NULL)                                            \
   V(bool, fp_stubs_generated, false)                                           \
   V(int, max_available_threads, 0)                                             \
   V(uint32_t, per_isolate_assert_data, 0xFFFFFFFFu)                            \
   V(PromiseRejectCallback, promise_reject_callback, NULL)                      \
@@ skipping 129 matching lines @@
   // True if at least one thread Enter'ed this isolate.
   bool IsInUse() { return entry_stack_ != NULL; }
 
   // Destroys the non-default isolates.
   // Sets default isolate into "has_been_disposed" state rather then destroying,
   // for legacy API reasons.
   void TearDown();
 
   static void GlobalTearDown();
 
+  void ClearSerializerData();
+
   // Find the PerThread for this particular (isolate, thread) combination
   // If one does not yet exist, return null.
   PerIsolateThreadData* FindPerThreadDataForThisThread();
 
   // Find the PerThread for given (isolate, thread) combination
   // If one does not yet exist, return null.
   PerIsolateThreadData* FindPerThreadDataForThread(ThreadId thread_id);
 
   // Returns the key used to store the pointer to the current isolate.
   // Used internally for V8 threads that do not execute JavaScript but still
@@ skipping 1023 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_