Tweak memory management in the serializer.

src/serialize.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 2028 matching lines @@
         return;
       }
     }
   }
   // One of the strings in the natives cache should match the resource.  We
   // don't expect any other kinds of external strings here.
   UNREACHABLE();
 }
 
 
-static Code* CloneCodeObject(HeapObject* code) {
-  Address copy = new byte[code->Size()];
-  MemCopy(copy, code->address(), code->Size());
-  return Code::cast(HeapObject::FromAddress(copy));
-}
-
-
-static void WipeOutRelocations(Code* code) {
+Address Serializer::ObjectSerializer::PrepareCode() {
+  // To make snapshots reproducible, we make a copy of the code object
+  // and wipe all pointers in the copy, which we then serialize.
+  Code* code = serializer_->CopyCode(Code::cast(object_));
+  // Code age headers are not serializable.
+  code->MakeYoung(serializer_->isolate());
   int mode_mask =
       RelocInfo::kCodeTargetMask |
       RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
       RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
       RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
   for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
     if (!(FLAG_enable_ool_constant_pool && it.rinfo()->IsInConstantPool())) {
       it.rinfo()->WipeOut();
     }
   }
+  // We need to wipe out the header fields *after* wiping out the
+  // relocations, because some of these fields are needed for the latter.
+  code->WipeOutHeader();
+  return code->address();
 }
 
 
 int Serializer::ObjectSerializer::OutputRawData(
     Address up_to, Serializer::ObjectSerializer::ReturnSkip return_skip) {
   Address object_start = object_->address();
   int base = bytes_processed_so_far_;
   int up_to_offset = static_cast<int>(up_to - object_start);
   int to_skip = up_to_offset - bytes_processed_so_far_;
   int bytes_to_output = to_skip;
@@ skipping 17 matching lines @@
       to_skip = 0;  /* This insn already skips. */                             \
     } else  /* NOLINT */
     COMMON_RAW_LENGTHS(RAW_CASE)
 #undef RAW_CASE
     {  /* NOLINT */
       // We always end up here if we are outputting the code of a code object.
       sink_->Put(kRawData, "RawData");
       sink_->PutInt(bytes_to_output, "length");
     }
 
-    // To make snapshots reproducible, we need to wipe out all pointers in code.
-    if (code_object_) {
-      Code* code = CloneCodeObject(object_);
-      // Code age headers are not serializable.
-      code->MakeYoung(serializer_->isolate());
-      WipeOutRelocations(code);
-      // We need to wipe out the header fields *after* wiping out the
-      // relocations, because some of these fields are needed for the latter.
-      code->WipeOutHeader();
-      object_start = code->address();
-    }
+    if (code_object_) object_start = PrepareCode();
 
     const char* description = code_object_ ? "Code" : "Byte";
 #ifdef MEMORY_SANITIZER
     // Object sizes are usually rounded up with uninitialized padding space.
     MSAN_MEMORY_IS_INITIALIZED(object_start + base, bytes_to_output);
 #endif  // MEMORY_SANITIZER
     sink_->PutRaw(object_start + base, bytes_to_output, description);
-    if (code_object_) delete[] object_start;
   }
   if (to_skip != 0 && return_skip == kIgnoringReturn) {
     sink_->Put(kSkip, "Skip");
     sink_->PutInt(to_skip, "SkipDistance");
     to_skip = 0;
   }
   return to_skip;
 }
 
 
@@ skipping 38 matching lines @@
   }
 }
 
 
 void Serializer::InitializeCodeAddressMap() {
   isolate_->InitializeLoggingAndCounters();
   code_address_map_ = new CodeAddressMap(isolate_);
 }
 
 
+Code* Serializer::CopyCode(Code* code) {
+  code_buffer_.Rewind(0);  // Clear buffer without deleting backing store.
+  int size = code->CodeSize();
+  code_buffer_.AddAll(Vector<byte>(code->address(), size));
+  return Code::cast(HeapObject::FromAddress(&code_buffer_.first()));
+}
+
+
 ScriptData* CodeSerializer::Serialize(Isolate* isolate,
                                       Handle<SharedFunctionInfo> info,
                                       Handle<String> source) {
   base::ElapsedTimer timer;
   if (FLAG_profile_deserialization) timer.Start();
   if (FLAG_trace_serializer) {
     PrintF("[Serializing from");
     Object* script = info->script();
     if (script->IsScript()) Script::cast(script)->name()->ShortPrint();
     PrintF("]\n");
@@ skipping 462 matching lines @@
   DisallowHeapAllocation no_gc;
   SerializedCodeData* scd = new SerializedCodeData(cached_data);
   SanityCheckResult r = scd->SanityCheck(source);
   if (r == CHECK_SUCCESS) return scd;
   cached_data->Reject();
   source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(r);
   delete scd;
   return NULL;
 }
 } }  // namespace v8::internal