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 86