xray_tsc.h revision 321369 
1//===-- xray_tsc.h ----------------------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is a part of XRay, a dynamic runtime instrumentation system.
11//
12//===----------------------------------------------------------------------===//
13#ifndef XRAY_EMULATE_TSC_H
14#define XRAY_EMULATE_TSC_H
15
16namespace __xray {
17static constexpr uint64_t NanosecondsPerSecond = 1000ULL * 1000 * 1000;
18}
19
20#if defined(__x86_64__)
21#include "xray_x86_64.inc"
22#elif defined(__powerpc64__)
23#include "xray_powerpc64.inc"
24#elif defined(__arm__) || defined(__aarch64__) || defined(__mips__)
25// Emulated TSC.
26// There is no instruction like RDTSCP in user mode on ARM. ARM's CP15 does
27//   not have a constant frequency like TSC on x86(_64), it may go faster
28//   or slower depending on CPU turbo or power saving mode. Furthermore,
29//   to read from CP15 on ARM a kernel modification or a driver is needed.
30//   We can not require this from users of compiler-rt.
31// So on ARM we use clock_gettime() which gives the result in nanoseconds.
32//   To get the measurements per second, we scale this by the number of
33//   nanoseconds per second, pretending that the TSC frequency is 1GHz and
34//   one TSC tick is 1 nanosecond.
35#include "sanitizer_common/sanitizer_common.h"
36#include "sanitizer_common/sanitizer_internal_defs.h"
37#include "xray_defs.h"
38#include <cerrno>
39#include <cstdint>
40#include <time.h>
41
42namespace __xray {
43
44inline bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
45
46ALWAYS_INLINE uint64_t readTSC(uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
47  timespec TS;
48  int result = clock_gettime(CLOCK_REALTIME, &TS);
49  if (result != 0) {
50    Report("clock_gettime(2) returned %d, errno=%d.", result, int(errno));
51    TS.tv_sec = 0;
52    TS.tv_nsec = 0;
53  }
54  CPU = 0;
55  return TS.tv_sec * NanosecondsPerSecond + TS.tv_nsec;
56}
57
58inline uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
59  return NanosecondsPerSecond;
60}
61
62} // namespace __xray
63
64#else
65#error Target architecture is not supported.
66#endif // CPU architecture
67
68#endif // XRAY_EMULATE_TSC_H
69