1 files changed, 68 insertions, 0 deletions
diff --git a/lib/xray/xray_tsc.h b/lib/xray/xray_tsc.h
new file mode 100644
index 0000000000000..4507564e7cd2c
--- /dev/null
+++ b/lib/xray/xray_tsc.h
@@ -0,0 +1,68 @@
+//===-- xray_tsc.h ----------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of XRay, a dynamic runtime instrumentation system.
+//
+//===----------------------------------------------------------------------===//
+#ifndef XRAY_EMULATE_TSC_H
+#define XRAY_EMULATE_TSC_H
+
+namespace __xray {
+static constexpr uint64_t NanosecondsPerSecond = 1000ULL * 1000 * 1000;
+}
+
+#if defined(__x86_64__)
+#include "xray_x86_64.inc"
+#elif defined(__powerpc64__)
+#include "xray_powerpc64.inc"
+#elif defined(__arm__) || defined(__aarch64__) || defined(__mips__)
+// Emulated TSC.
+// There is no instruction like RDTSCP in user mode on ARM. ARM's CP15 does
+//   not have a constant frequency like TSC on x86(_64), it may go faster
+//   or slower depending on CPU turbo or power saving mode. Furthermore,
+//   to read from CP15 on ARM a kernel modification or a driver is needed.
+//   We can not require this from users of compiler-rt.
+// So on ARM we use clock_gettime() which gives the result in nanoseconds.
+//   To get the measurements per second, we scale this by the number of
+//   nanoseconds per second, pretending that the TSC frequency is 1GHz and
+//   one TSC tick is 1 nanosecond.
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "xray_defs.h"
+#include <cerrno>
+#include <cstdint>
+#include <time.h>
+
+namespace __xray {
+
+inline bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
+
+ALWAYS_INLINE uint64_t readTSC(uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
+  timespec TS;
+  int result = clock_gettime(CLOCK_REALTIME, &TS);
+  if (result != 0) {
+    Report("clock_gettime(2) returned %d, errno=%d.", result, int(errno));
+    TS.tv_sec = 0;
+    TS.tv_nsec = 0;
+  }
+  CPU = 0;
+  return TS.tv_sec * NanosecondsPerSecond + TS.tv_nsec;
+}
+
+inline uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
+  return NanosecondsPerSecond;
+}
+
+} // namespace __xray
+
+#else
+#error Target architecture is not supported.
+#endif // CPU architecture
+
+#endif // XRAY_EMULATE_TSC_H