[compiler-rt] d905c7e - [XRay][SystemZ] Use stckf for non-clang compilers (#125289)

[via llvm-commits]

Author: Kai Nacke
Date: 2025-02-06T16:08:05-05:00
New Revision: d905c7e316b941afcef32e28073b3e77c536407c

URL: https://github.com/llvm/llvm-project/commit/d905c7e316b941afcef32e28073b3e77c536407c
DIFF: https://github.com/llvm/llvm-project/commit/d905c7e316b941afcef32e28073b3e77c536407c.diff

LOG: [XRay][SystemZ] Use stckf for non-clang compilers (#125289)

Turns out there are users who use gcc to compile compiler-rt. Using the
clang-specific builtin function `__builtin_readcyclecounter()` does not
work in this case.
Solution is to use inline assembly using the stckf instruction in case
the compiler is not clang.

Added: 
    

Modified: 
    compiler-rt/lib/xray/xray_tsc.h

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/xray/xray_tsc.h b/compiler-rt/lib/xray/xray_tsc.h
index 17e06c7035d85cc..118b6f00e33ea53 100644
--- a/compiler-rt/lib/xray/xray_tsc.h
+++ b/compiler-rt/lib/xray/xray_tsc.h
@@ -96,7 +96,13 @@ namespace __xray {
 inline bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
 
 ALWAYS_INLINE uint64_t readTSC(uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
+#if __has_builtin(__builtin_readcyclecounter)
   return __builtin_readcyclecounter();
+#else
+  uint64_t Cycles;
+  asm volatile("stckf %0" : : "Q"(Cycles) : "cc");
+  return Cycles;
+#endif
 }
 
 inline uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {