Non-SFI NaCl: Allow CLOCK_SYSTEM_TRACE on Chrome OS

base/time/time_posix.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 "base/time/time.h"
 
 #include <stdint.h>
 #include <sys/time.h>
 #include <time.h>
 #if defined(OS_ANDROID) && !defined(__LP64__)
@@ skipping 302 matching lines @@
 TimeTicks TimeTicks::ThreadNow() {
 #if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
     defined(OS_ANDROID)
   return ClockNow(CLOCK_THREAD_CPUTIME_ID);
 #else
   NOTREACHED();
   return TimeTicks();
 #endif
 }
 
-#if defined(OS_CHROMEOS)
-// Force definition of the system trace clock; it is a chromeos-only api
-// at the moment and surfacing it in the right place requires mucking
-// with glibc et al.
-#define CLOCK_SYSTEM_TRACE 11
-
+// NaCl IRT does not support the Chrome OS specific clock
+// ID. build_nexe.py sets OS_CHROMEOS without any other OS_* macros so

[Mark Seaborn, 2014/06/03 17:23:28]

Maybe say it's common.gypi that does that instead of or as well as mentioning
build_nexe.py?

There should really be a TODO here to fix this #define.

[hamaji, 2014/06/03 18:44:08]

Yeah, you are right. Sorry for the wrong description. Update the comment and
added a TODO.

+// we need to check __native_client__ explicitly.
+#if defined(OS_CHROMEOS) && !defined(__native_client__)
 // static
 TimeTicks TimeTicks::NowFromSystemTraceTime() {
   uint64_t absolute_micro;
 
   struct timespec ts;
-  if (clock_gettime(CLOCK_SYSTEM_TRACE, &ts) != 0) {
+  if (clock_gettime(kClockSystemTrace, &ts) != 0) {

[jln (very slow on Chromium), 2014/06/03 06:15:44]

If you want to, you can also COMPILE_ASSERT that kClockSystemTrace ==
CLOCK_SYSTEM_TRACE here.

[hamaji, 2014/06/03 06:26:49]

Hmm I don't understand your suggestion. As written in the original comment (now
this comment is moved to time.h), CLOCK_SYSTEM_TRACE is not defined in glibc
header. This is why we define this magic number in Chromium source. If we have
CLOCK_SYSTEM_TRACE, we can just use it instead of defining it by ourselves. So,
I think we cannot check the value.

[jln (very slow on Chromium), 2014/06/03 19:10:29]

Ahh, sorry I missed that CLOCK_SYSTEM_TRACE was in a #define above. I thought it
was defined in this file but you had trouble getting the right include in
components/

     // NB: fall-back for a chrome os build running on linux
     return HighResNow();
   }
 
   absolute_micro =
       (static_cast<int64>(ts.tv_sec) * Time::kMicrosecondsPerSecond) +
       (static_cast<int64>(ts.tv_nsec) / Time::kNanosecondsPerMicrosecond);
 
   return TimeTicks(absolute_micro);
 }
 
-#else // !defined(OS_CHROMEOS)
+#else // !(defined(OS_CHROMEOS) && !defined(__native_client__))
 
 // static
 TimeTicks TimeTicks::NowFromSystemTraceTime() {
   return HighResNow();
 }
 
-#endif // defined(OS_CHROMEOS)
+#endif // defined(OS_CHROMEOS) && !defined(__native_client__)
 
 #endif  // !OS_MACOSX
 
 // static
 Time Time::FromTimeVal(struct timeval t) {
   DCHECK_LT(t.tv_usec, static_cast<int>(Time::kMicrosecondsPerSecond));
   DCHECK_GE(t.tv_usec, 0);
   if (t.tv_usec == 0 && t.tv_sec == 0)
     return Time();
   if (t.tv_usec == static_cast<suseconds_t>(Time::kMicrosecondsPerSecond) - 1 &&
@@ skipping 17 matching lines @@
     result.tv_usec = static_cast<suseconds_t>(Time::kMicrosecondsPerSecond) - 1;
     return result;
   }
   int64 us = us_ - kTimeTToMicrosecondsOffset;
   result.tv_sec = us / Time::kMicrosecondsPerSecond;
   result.tv_usec = us % Time::kMicrosecondsPerSecond;
   return result;
 }
 
 }  // namespace base