compiler-rt/lib/xray/xray_utils.h

   1 //===-- xray_utils.h --------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of XRay, a dynamic runtime instrumentation system.
  10 //
  11 // Some shared utilities for the XRay runtime implementation.
  12 //
  13 //===----------------------------------------------------------------------===//
  14 #ifndef XRAY_UTILS_H
  15 #define XRAY_UTILS_H
  16
  17 #include <cstddef>
  18 #include <cstdint>
  19 #include <sys/types.h>
  20 #include <utility>
  21
  22 #include "sanitizer_common/sanitizer_common.h"
  23 #if SANITIZER_FUCHSIA
  24 #include <zircon/types.h>
  25 #endif
  26
  27 namespace __xray {
  28
  29 class LogWriter {
  30 public:
  31 #if SANITIZER_FUCHSIA
  32  LogWriter(zx_handle_t Vmo) : Vmo(Vmo) {}
  33 #else
  34   explicit LogWriter(int Fd) : Fd(Fd) {}
  35 #endif
  36  ~LogWriter();
  37
  38  // Write a character range into a log.
  39  void WriteAll(const char *Begin, const char *End);
  40
  41  void Flush();
  42
  43  // Returns a new log instance initialized using the flag-provided values.
  44  static LogWriter *Open();
  45  // Closes and deallocates the log instance.
  46  static void Close(LogWriter *LogWriter);
  47
  48 private:
  49 #if SANITIZER_FUCHSIA
  50  zx_handle_t Vmo = ZX_HANDLE_INVALID;
  51  uint64_t Offset = 0;
  52 #else
  53  int Fd = -1;
  54 #endif
  55 };
  56
  57 constexpr size_t gcd(size_t a, size_t b) {
  58   return (b == 0) ? a : gcd(b, a % b);
  59 }
  60
  61 constexpr size_t lcm(size_t a, size_t b) { return a * b / gcd(a, b); }
  62
  63 constexpr size_t nearest_boundary(size_t number, size_t multiple) {
  64   return multiple * ((number / multiple) + (number % multiple ? 1 : 0));
  65 }
  66
  67 constexpr size_t next_pow2_helper(size_t num, size_t acc) {
  68   return (1u << acc) >= num ? (1u << acc) : next_pow2_helper(num, acc + 1);
  69 }
  70
  71 constexpr size_t next_pow2(size_t number) {
  72   return next_pow2_helper(number, 1);
  73 }
  74
  75 template <class T> constexpr T &max(T &A, T &B) { return A > B ? A : B; }
  76
  77 template <class T> constexpr T &min(T &A, T &B) { return A <= B ? A : B; }
  78
  79 constexpr ptrdiff_t diff(uintptr_t A, uintptr_t B) {
  80   return max(A, B) - min(A, B);
  81 }
  82
  83 } // namespace __xray
  84
  85 #endif // XRAY_UTILS_H