Initial support for AIX (#1021)

* Init support of AIX

* make sysinfo change AIX specific

* Relocate TBF

* Add comments for .csect psudo op.

2 files changed, 6 insertions, 0 deletions

diff --git a/absl/base/internal/sysinfo.cc b/absl/base/internal/sysinfo.cc
index 08a1e288..a7cfb461 100644
--- a/absl/base/internal/sysinfo.cc
+++ b/absl/base/internal/sysinfo.cc
@@ -131,6 +131,8 @@ static int GetNumCPUs() {
 #elif defined(_WIN32)
   const unsigned hardware_concurrency = Win32NumCPUs();
   return hardware_concurrency ? hardware_concurrency : 1;
+#elif defined(_AIX)
+  return sysconf(_SC_NPROCESSORS_ONLN);
 #else
   // Other possibilities:
   //  - Read /sys/devices/system/cpu/online and use cpumask_parse()
diff --git a/absl/base/internal/unscaledcycleclock.cc b/absl/base/internal/unscaledcycleclock.cc
index fc07e300..4d352bd1 100644
--- a/absl/base/internal/unscaledcycleclock.cc
+++ b/absl/base/internal/unscaledcycleclock.cc
@@ -87,6 +87,10 @@ int64_t UnscaledCycleClock::Now() {
 double UnscaledCycleClock::Frequency() {
 #ifdef __GLIBC__
   return __ppc_get_timebase_freq();
+#elif defined(_AIX)
+  // This is the same constant value as returned by
+  // __ppc_get_timebase_freq().
+  return static_cast<double>(512000000);
 #elif defined(__FreeBSD__)
   static once_flag init_timebase_frequency_once;
   static double timebase_frequency = 0.0;