make debug mode ~20% faster on linux

content/common/set_process_title.cc

 // Copyright (c) 2012 The Chromium 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 "content/common/set_process_title.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_SOLARIS)
 #include <limits.h>
@@ skipping 24 matching lines @@
   !defined(OS_ANDROID)
 
 void SetProcessTitleFromCommandLine(const char** main_argv) {
   // Build a single string which consists of all the arguments separated
   // by spaces. We can't actually keep them separate due to the way the
   // setproctitle() function works.
   std::string title;
   bool have_argv0 = false;
 
 #if defined(OS_LINUX)
-  DCHECK_EQ(base::PlatformThread::CurrentId(), getpid());

[piman, 2014/05/20 05:09:22]

nit: maybe DCHECK_EQ(gettid(), getpid()); ?

I think the goal of the DCHECK is to verify we're on the main thread (but before
any MessageLoop is created or anything), otherwise things would be racy.

-
   if (main_argv)
     setproctitle_init(main_argv);
 
   // In Linux we sometimes exec ourselves from /proc/self/exe, but this makes us
   // show up as "exe" in process listings. Read the symlink /proc/self/exe and
   // use the path it points at for our process title. Note that this is only for
   // display purposes and has no TOCTTOU security implications.
   base::FilePath target;
   base::FilePath self_exe(base::kProcSelfExe);
   if (base::ReadSymbolicLink(self_exe, &target)) {
@@ skipping 26 matching lines @@
 #else
 
 // All other systems (basically Windows & Mac) have no need or way to implement
 // this function.
 void SetProcessTitleFromCommandLine(const char** /* main_argv */) {
 }
 
 #endif
 
 } // namespace content