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1//===-- MmapUtils.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-exception6//7//===----------------------------------------------------------------------===//8//9// This file contains compatibility-related preprocessor directives related10// to mmap.11//12//===----------------------------------------------------------------------===//13 14#ifdef __linux__15#include <sys/mman.h>16#include <sys/syscall.h>17 18// Before kernel 4.17, Linux did not support MAP_FIXED_NOREPLACE, so if it is19// not available, simplfy define it as MAP_FIXED which performs the same20// function but does not guarantee existing mappings won't get clobbered.21#ifndef MAP_FIXED_NOREPLACE22#define MAP_FIXED_NOREPLACE MAP_FIXED23#endif24 25// Some 32-bit architectures don't have mmap and define mmap2 instead. The only26// difference between the two syscalls is that mmap2's offset parameter is in27// terms 4096 byte offsets rather than individual bytes, so for our purposes28// they are effectively the same as all ofsets here are set to 0.29#if defined(SYS_mmap2) && !defined(SYS_mmap)30#define SYS_mmap SYS_mmap231#endif32#endif // __linux__33