Implement CPU time for OS X and POSIX.

src/base/platform/time.cc

Index: src/base/platform/time.cc
diff --git a/src/base/platform/time.cc b/src/base/platform/time.cc
index 6d5e538970cfd8e8b3608c196b79c361a44c4107..14a0d1e6db97be0cb97ca91630bd1d99e55f67f8 100644
--- a/src/base/platform/time.cc
+++ b/src/base/platform/time.cc
@@ -10,6 +10,7 @@
 #include <unistd.h>
 #endif
 #if V8_OS_MACOSX
+#include <mach/mach.h>
 #include <mach/mach_time.h>
 #endif
 
@@ -19,11 +20,66 @@
 #if V8_OS_WIN
 #include "src/base/atomicops.h"
 #include "src/base/lazy-instance.h"
-#include "src/base/win32-headers.h"

[fmeawad, 2016/05/09 21:50:32]

This line should be untouched in this CL.

[lpy, 2016/05/09 22:13:41]

Done.

 #endif
 #include "src/base/cpu.h"
 #include "src/base/logging.h"
 #include "src/base/platform/platform.h"
+#include "src/base/safe_math.h"
+
+namespace {
+
+#if V8_OS_MACOSX
+int64_t ComputeThreadTicks() {
+  mach_port_t thread = mach_thread_self();
+  mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
+  thread_basic_info_data_t thread_info_data;
+
+  if (thread == MACH_PORT_NULL) {
+    return 0;
+  }
+
+  kern_return_t kr = thread_info(
+      thread,
+      THREAD_BASIC_INFO,
+      reinterpret_cast<thread_info_t>(&thread_info_data),
+      &thread_info_count);
+  USE(kr);

[fmeawad, 2016/05/09 21:50:32]

You are loosing the check here that kr == KERN_SUCCESS

[lpy, 2016/05/09 22:13:41]

Done.

+
+  v8::base::CheckedNumeric<int64_t> absolute_micros(
+      thread_info_data.user_time.seconds);
+  absolute_micros *= v8::base::Time::kMicrosecondsPerSecond;
+  absolute_micros += thread_info_data.user_time.microseconds;
+  return absolute_micros.ValueOrDie();
+}
+#elif V8_OS_POSIX
+int64_t ConvertTimespecToMicros(const struct timespec& ts) {
+  v8::base::internal::CheckedNumeric<int64_t> result(ts.tv_sec);
+  result *= v8::base::Time::kMicrosecondsPerSecond;
+  result += (ts.tv_nsec / v8::base::Time::kNanosecondsPerMicrosecond);
+  return result.ValueOrDie();
+}
+
+// Helper function to get results from clock_gettime() and convert to a
+// microsecond timebase. Minimum requirement is MONOTONIC_CLOCK to be supported
+// on the system. FreeBSD 6 has CLOCK_MONOTONIC but defines
+// _POSIX_MONOTONIC_CLOCK to -1.
+int64_t ClockNow(clockid_t clk_id) {

[fmeawad, 2016/05/09 21:50:32]

If this method is only used for CLOCK_THREAD_CPU, then maybe it should be
inlined.

if we are using clock_gettime somewhere else, then they should all call this
method instead.

[lpy, 2016/05/09 22:13:41]

Done.

+#if (defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0) || \
+  defined(V8_OS_BSD) || defined(V8_OS_ANDROID)
+  struct timespec ts;
+  if (clock_gettime(clk_id, &ts) != 0) {
+    UNREACHABLE();
+    return 0;
+  }
+  return ConvertTimespecToMicros(ts);
+#else  // Monotonic clock not supported.
+  return 0;
+#endif
+}
+#endif  // V8_OS_MACOSX
+
+
+}  // namespace
 
 namespace v8 {
 namespace base {
@@ -560,5 +616,28 @@ bool TimeTicks::IsHighResolutionClockWorking() {
 
 #endif  // V8_OS_WIN
 
+
+bool ThreadTicks::IsSupported() {
+#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+    defined(V8_OS_MACOSX) || defined(V8_OS_ANDROID)
+    return true;
+#else
+    return false;
+#endif
+}
+
+
+ThreadTicks ThreadTicks::Now() {
+#if V8_OS_MACOSX
+  return ThreadTicks(ComputeThreadTicks());
+#elif(defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+  defined(V8_OS_ANDROID)
+  return ThreadTicks(ClockNow(CLOCK_THREAD_CPUTIME_ID));
+#else
+  UNREACHABLE();
+  return ThreadTicks();
+#endif
+}
+
 }  // namespace base
 }  // namespace v8