[deserializer] Dump the disassembly of deserialized code

Prints the disassembly of code objects on the heap after
deserialization, if --print-builtin-code is on. This allows us to
annotate the disassembly of builtins in the same way as we do optimised
code now, for example using `perf report --objdump=v8/tools/objdump`.

Change-Id: I1781302de6fca035ea9bd4c4f7d58796a957f4af
Reviewed-on: https://chromium-review.googlesource.com/456340Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43923}

src/snapshot/deserializer.cc

@@ -113,6 +113,9 @@ void Deserializer::Deserialize(Isolate* isolate) {
         isolate_->heap()->undefined_value());
   }
 
+  // If needed, print the dissassembly of deserialized code objects.
+  PrintDisassembledCodeObjects();
+
   // Issue code events for newly deserialized code objects.
   LOG_CODE_EVENT(isolate_, LogCodeObjects());
   LOG_CODE_EVENT(isolate_, LogBytecodeHandlers());
@@ -250,6 +253,26 @@ void Deserializer::DeserializeEmbedderFields(
   }
 }
 
+void Deserializer::PrintDisassembledCodeObjects() {
+#ifdef ENABLE_DISASSEMBLER
+  if (FLAG_print_builtin_code) {
+    Heap* heap = isolate_->heap();
+    HeapIterator iterator(heap);
+    DisallowHeapAllocation no_gc;
+
+    CodeTracer::Scope tracing_scope(isolate_->GetCodeTracer());
+    OFStream os(tracing_scope.file());
+
+    for (HeapObject* obj = iterator.next(); obj != NULL;
+         obj = iterator.next()) {
+      if (obj->IsCode()) {
+        Code::cast(obj)->Disassemble(nullptr, os);
+      }
+    }
+  }
+#endif
+}
+
 // Used to insert a deserialized internalized string into the string table.
 class StringTableInsertionKey : public HashTableKey {
  public:

src/snapshot/deserializer.h

@@ -98,6 +98,8 @@ class Deserializer : public SerializerDeserializer {
 
   void CommitPostProcessedObjects(Isolate* isolate);
 
+  void PrintDisassembledCodeObjects();
+
   // Fills in some heap data in an area from start to end (non-inclusive).  The
   // space id is used for the write barrier.  The object_address is the address
   // of the object we are writing into, or NULL if we are not writing into an