[XRay][compiler-rt] Add another work-around to XRay FDR tests when TSC emulation is needed

This patch applies a work-around to the XRay FDR tests when TSC emulation is 
needed because the processor frequency cannot be determined.

This fixes PR32620 using the suggestion given by Dean in comment 1.

Reviewers: dberris

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31967

llvm-svn: 300017

2 files changed, 5 insertions, 2 deletions

diff --git a/compiler-rt/lib/xray/xray_fdr_logging.cc b/compiler-rt/lib/xray/xray_fdr_logging.cc
index f2ff4076e3c..5c6bbd41cfc 100644
--- a/compiler-rt/lib/xray/xray_fdr_logging.cc
+++ b/compiler-rt/lib/xray/xray_fdr_logging.cc
@@ -120,7 +120,8 @@ XRayLogFlushStatus fdrLoggingFlush() XRAY_NEVER_INSTRUMENT {
   XRayFileHeader Header;
   Header.Version = 1;
   Header.Type = FileTypes::FDR_LOG;
-  Header.CycleFrequency = getTSCFrequency();
+  Header.CycleFrequency = probeRequiredCPUFeatures()
+                          ? getTSCFrequency() : __xray::NanosecondsPerSecond;
   // FIXME: Actually check whether we have 'constant_tsc' and 'nonstop_tsc'
   // before setting the values in the header.
   Header.ConstantTSC = 1;
diff --git a/compiler-rt/lib/xray/xray_fdr_logging_impl.h b/compiler-rt/lib/xray/xray_fdr_logging_impl.h
index 20e89d6c12b..bc795b3b647 100644
--- a/compiler-rt/lib/xray/xray_fdr_logging_impl.h
+++ b/compiler-rt/lib/xray/xray_fdr_logging_impl.h
@@ -423,7 +423,9 @@ static inline void processFunctionHook(
       return;
     }
 
-    uint64_t CycleFrequency = getTSCFrequency();
+    uint64_t CycleFrequency = probeRequiredCPUFeatures()
+                              ? getTSCFrequency()
+                              : __xray::NanosecondsPerSecond;
     NumberOfTicksThreshold = CycleFrequency *
                              flags()->xray_fdr_log_func_duration_threshold_us /
                              1000000;