[PATCH] D43981: [XRay] [compiler-rt] [macosx] Add getTSCFrequency implementation for macOS.

[Nicholas Levin via Phabricator via llvm-commits]

nglevin updated this revision to Diff 136654.
nglevin added a comment.

Transform mach_timebase_info_data_t into an "assured once" initialisation, per feedback.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D43981

Files:
  lib/xray/xray_x86_64.cc


Index: lib/xray/xray_x86_64.cc
===================================================================
--- lib/xray/xray_x86_64.cc
+++ lib/xray/xray_x86_64.cc
@@ -6,6 +6,8 @@
 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 #include <sys/types.h>
 #include <sys/sysctl.h>
+#elif SANITIZER_MAC
+#include <mach/mach_time.h>
 #endif
 
 #include <atomic>
@@ -92,6 +94,19 @@
     return 0;
     
 }
+#elif SANITIZER_MAC
+static const mach_timebase_info_data_t TI = [] {
+  mach_timebase_info_data_t LocalTI;
+  mach_timebase_info(&LocalTI);
+  return LocalTI;
+}();
+
+uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
+    uint64_t currentTime = mach_absolute_time();
+    currentTime *= TI.numer;
+    currentTime /= TI.denom;
+    return currentTime;
+}
 #else
 uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
     /* Not supported */


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