64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
//===- Linux/Memory.cpp - Linux Memory Implementation -----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Reid Spencer and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides the Linux specific implementation of various Memory
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// management utilities
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//
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//===----------------------------------------------------------------------===//
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// Include the generic unix implementation
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#include "../Unix/Memory.cpp"
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#include "llvm/System/Process.h"
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#include <sys/mman.h>
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namespace llvm {
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using namespace sys;
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only Linux specific code
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//=== and must not be generic UNIX code (see ../Unix/Memory.cpp)
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//===----------------------------------------------------------------------===//
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/// AllocateRWXMemory - Allocate a slab of memory with read/write/execute
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/// permissions. This is typically used for JIT applications where we want
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/// to emit code to the memory then jump to it. Getting this type of memory
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/// is very OS specific.
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///
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MemoryBlock Memory::AllocateRWX(unsigned NumBytes) {
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if (NumBytes == 0) return MemoryBlock();
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static const long pageSize = Process::GetPageSize();
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unsigned NumPages = (NumBytes+pageSize-1)/pageSize;
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void *pa = mmap(0, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
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MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 0, 0);
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if (pa == MAP_FAILED) {
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char msg[MAXPATHLEN];
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strerror_r(errno, msg, MAXPATHLEN-1);
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throw std::string("Can't allocate RWX Memory: ") + msg;
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}
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MemoryBlock result;
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result.Address = pa;
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result.Size = NumPages*pageSize;
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return result;
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}
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void Memory::ReleaseRWX(MemoryBlock& M) {
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if (M.Address == 0 || M.Size == 0) return;
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if (0 != munmap(M.Address, M.Size)) {
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char msg[MAXPATHLEN];
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strerror_r(errno, msg, MAXPATHLEN-1);
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throw std::string("Can't release RWX Memory: ") + msg;
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}
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}
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}
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// vim: sw=2 smartindent smarttab tw=80 autoindent expandtab
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