Probe same-isolate compilation cache before deserializing.

src/compiler.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/compiler.h"
 
 #include "src/ast-numbering.h"
 #include "src/ast-this-access-visitor.h"
@@ skipping 1275 matching lines @@
   int source_length = source->length();
   isolate->counters()->total_load_size()->Increment(source_length);
   isolate->counters()->total_compile_size()->Increment(source_length);
 
   CompilationCache* compilation_cache = isolate->compilation_cache();
 
   // Do a lookup in the compilation cache but not for extensions.
   MaybeHandle<SharedFunctionInfo> maybe_result;
   Handle<SharedFunctionInfo> result;
   if (extension == NULL) {
-    if (FLAG_serialize_toplevel &&
+    maybe_result = compilation_cache->LookupScript(
+        source, script_name, line_offset, column_offset, is_shared_cross_origin,
+        context);
+    if (maybe_result.is_null() && FLAG_serialize_toplevel &&
         compile_options == ScriptCompiler::kConsumeCodeCache &&
         !isolate->debug()->is_loaded()) {
       HistogramTimerScope timer(isolate->counters()->compile_deserialize());
       Handle<SharedFunctionInfo> result;
       if (CodeSerializer::Deserialize(isolate, *cached_data, source)
               .ToHandle(&result)) {
         return result;
       }
       // Deserializer failed. Fall through to compile.
-    } else {
-      maybe_result = compilation_cache->LookupScript(
-          source, script_name, line_offset, column_offset,
-          is_shared_cross_origin, context);
     }
   }
 
   base::ElapsedTimer timer;
   if (FLAG_profile_deserialization && FLAG_serialize_toplevel &&
       compile_options == ScriptCompiler::kProduceCodeCache) {
     timer.Start();
   }
 
   if (!maybe_result.ToHandle(&result)) {
@@ skipping 264 matching lines @@
   AllowHandleDereference allow_deref;
   bool tracing_on = info()->IsStub()
       ? FLAG_trace_hydrogen_stubs
       : (FLAG_trace_hydrogen &&
          info()->closure()->PassesFilter(FLAG_trace_hydrogen_filter));
   return (tracing_on &&
       base::OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL);
 }
 
 } }  // namespace v8::internal