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
LogWriter(zx_handle_t Vmo)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
gcd(size_t a,size_t b)57 constexpr size_t gcd(size_t a, size_t b) {
58 return (b == 0) ? a : gcd(b, a % b);
59 }
60
lcm(size_t a,size_t b)61 constexpr size_t lcm(size_t a, size_t b) { return a * b / gcd(a, b); }
62
nearest_boundary(size_t number,size_t multiple)63 constexpr size_t nearest_boundary(size_t number, size_t multiple) {
64 return multiple * ((number / multiple) + (number % multiple ? 1 : 0));
65 }
66
next_pow2_helper(size_t num,size_t acc)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
next_pow2(size_t number)71 constexpr size_t next_pow2(size_t number) {
72 return next_pow2_helper(number, 1);
73 }
74
max(T & A,T & B)75 template <class T> constexpr T &max(T &A, T &B) { return A > B ? A : B; }
76
min(T & A,T & B)77 template <class T> constexpr T &min(T &A, T &B) { return A <= B ? A : B; }
78
diff(uintptr_t A,uintptr_t B)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