[serializer] tweak startup serializer for warming up.

src/snapshot/startup-serializer.cc

 // 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/snapshot/startup-serializer.h"
 
 #include "src/objects-inl.h"
 #include "src/v8threads.h"
 
 namespace v8 {
 namespace internal {
 
 StartupSerializer::StartupSerializer(
     Isolate* isolate, SnapshotByteSink* sink,
     FunctionCodeHandling function_code_handling)
     : Serializer(isolate, sink),
       function_code_handling_(function_code_handling),
       serializing_builtins_(false) {
   InitializeCodeAddressMap();
 }
 
 StartupSerializer::~StartupSerializer() {
   OutputStatistics("StartupSerializer");
 }
 
 void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
                                         WhereToPoint where_to_point, int skip) {
   DCHECK(!obj->IsJSFunction());
 
-  if (obj->IsCode()) {
+  if (function_code_handling_ == CLEAR_FUNCTION_CODE) {
+    if (obj->IsCode()) {
+      Code* code = Code::cast(obj);
+      // If the function code is compiled (either as native code or bytecode),
+      // replace it with lazy-compile builtin. Only exception is when we are
+      // serializing the canonical interpreter-entry-trampoline builtin.
+      if (code->kind() == Code::FUNCTION ||
+          (!serializing_builtins_ && code->is_interpreter_entry_trampoline())) {
+        obj = isolate()->builtins()->builtin(Builtins::kCompileLazy);
+      }
+    } else if (obj->IsBytecodeArray()) {
+      obj = isolate()->heap()->undefined_value();
+    }
+  } else if (obj->IsCode()) {
+    DCHECK_EQ(KEEP_FUNCTION_CODE, function_code_handling_);
     Code* code = Code::cast(obj);
-    // If the function code is compiled (either as native code or bytecode),
-    // replace it with lazy-compile builtin. Only exception is when we are
-    // serializing the canonical interpreter-entry-trampoline builtin.
-    if (function_code_handling_ == CLEAR_FUNCTION_CODE &&
-        (code->kind() == Code::FUNCTION ||
-         (!serializing_builtins_ && code->is_interpreter_entry_trampoline()))) {
-      obj = isolate()->builtins()->builtin(Builtins::kCompileLazy);
+    if (code->kind() == Code::FUNCTION) {
+      code->ClearInlineCaches();
+      code->set_profiler_ticks(0);
     }
-  } else if (obj->IsBytecodeArray()) {
-    obj = isolate()->heap()->undefined_value();
   }
 
   int root_index = root_index_map_.Lookup(obj);
   // We can only encode roots as such if it has already been serialized.
   // That applies to root indices below the wave front.
   if (root_index != RootIndexMap::kInvalidRootIndex) {
     if (root_has_been_serialized_.test(root_index)) {
       PutRoot(root_index, obj, how_to_code, where_to_point, skip);
       return;
     }
@@ skipping 94 matching lines @@
       root_index == Heap::kStackLimitRootIndex ||
       root_index == Heap::kRealStackLimitRootIndex) {
     return true;
   }
   return Heap::RootIsImmortalImmovable(root_index) !=
          serializing_immortal_immovables_roots_;
 }
 
 }  // namespace internal
 }  // namespace v8