Adding 'isolates' argument to LOG to get rid of multiple TLS fetches in profiling.

src/ia32/assembler-ia32.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 111 matching lines @@
   CodeDesc desc;
   assm.GetCode(&desc);
   Object* code;
   { MaybeObject* maybe_code = HEAP->CreateCode(desc,
                                                Code::ComputeFlags(Code::STUB),
                                                Handle<Code>::null());
     if (!maybe_code->ToObject(&code)) return;
   }
   if (!code->IsCode()) return;
 
-  PROFILE(CodeCreateEvent(Logger::BUILTIN_TAG,
+  PROFILE(ISOLATE,
+          CodeCreateEvent(Logger::BUILTIN_TAG,
                           Code::cast(code), "CpuFeatures::Probe"));
   typedef uint64_t (*F0)();
   F0 probe = FUNCTION_CAST<F0>(Code::cast(code)->entry());
   supported_ = probe();
   found_by_runtime_probing_ = supported_;
   uint64_t os_guarantees = OS::CpuFeaturesImpliedByPlatform();
   supported_ |= os_guarantees;
   found_by_runtime_probing_ &= portable ? ~os_guarantees : 0;
 }
 
@@ skipping 2651 matching lines @@
     fprintf(coverage_log, "%s\n", file_line);
     fflush(coverage_log);
   }
 }
 
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32