AsanCoverage: make the filenames of zygote/gpu coverage files more unique.

content/gpu/gpu_main.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 <stdlib.h>
 
 #if defined(OS_WIN)
 #include <dwmapi.h>
 #include <windows.h>
 #endif
@@ skipping 432 matching lines @@
 
   WarmUpSandboxNvidia(gpu_info, should_initialize_gl_context);
 
   if (watchdog_thread) {
     // LinuxSandbox needs to be able to ensure that the thread
     // has really been stopped.
     LinuxSandbox::StopThread(watchdog_thread);
   }
 
 #if defined(ADDRESS_SANITIZER)
+  std::stringstream ss;
+  ss << "gpu." << base::RandUint64();
+  std::string sancov_file_name = ss.str();

[jln (very slow on Chromium), 2014/06/03 21:43:40]

please do:

const std::string sancov_file_name = "gpu." +
base::Uint64ToString(base::RandUint64());

instead.

[earthdok, 2014/06/03 21:49:27]

Done.

   LinuxSandbox* linux_sandbox = LinuxSandbox::GetInstance();
   linux_sandbox->sanitizer_args()->coverage_sandboxed = 1;
-  linux_sandbox->sanitizer_args()->coverage_fd = -1;
+  linux_sandbox->sanitizer_args()->coverage_fd =
+      __sanitizer_maybe_open_cov_file(sancov_file_name.c_str());
   linux_sandbox->sanitizer_args()->coverage_max_block_size = 0;
 #endif
 
   // LinuxSandbox::InitializeSandbox() must always be called
   // with only one thread.
   res = LinuxSandbox::InitializeSandbox();
   if (watchdog_thread) {
     watchdog_thread->Start();
   }
 
@@ skipping 14 matching lines @@
     return true;
   }
 
   return false;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace.
 
 }  // namespace content