CPUProfiler: Improve line numbers support in profiler.

src/compiler.cc

 // Copyright 2012 the V8 project authors. 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.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1182 matching lines @@
 
   // Log the code generation. If source information is available include
   // script name and line number. Check explicitly whether logging is
   // enabled as finding the line number is not free.
   if (info->isolate()->logger()->is_logging_code_events() ||
       info->isolate()->cpu_profiler()->is_profiling()) {
     Handle<Script> script = info->script();
     Handle<Code> code = info->code();
     if (*code == info->isolate()->builtins()->builtin(Builtins::kLazyCompile))
       return;
+    int line_num = GetScriptLineNumber(script, shared->start_position()) + 1;
+    USE(line_num);

[yurys, 2013/07/06 05:03:22]

It seems that you can drop this line as line_num is always used.

     if (script->name()->IsString()) {
-      int line_num = GetScriptLineNumber(script, shared->start_position()) + 1;
-      USE(line_num);
       PROFILE(info->isolate(),
               CodeCreateEvent(Logger::ToNativeByScript(tag, *script),
                               *code,
                               *shared,
                               info,
                               String::cast(script->name()),
                               line_num));
     } else {
       PROFILE(info->isolate(),
               CodeCreateEvent(Logger::ToNativeByScript(tag, *script),
                               *code,
                               *shared,
                               info,
-                              shared->DebugName()));
+                              info->isolate()->heap()->empty_string(),
+                              line_num));
     }
   }
 
   GDBJIT(AddCode(Handle<String>(shared->DebugName()),
                  Handle<Script>(info->script()),
                  Handle<Code>(info->code()),
                  info));
 }
 
 
@@ skipping 17 matching lines @@
 
 
 bool CompilationPhase::ShouldProduceTraceOutput() const {
   // Produce trace output if flag is set so that the first letter of the
   // phase name matches the command line parameter FLAG_trace_phase.
   return (FLAG_trace_hydrogen &&
           OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL);
 }
 
 } }  // namespace v8::internal