1 //===- Linux/Memory.cpp - Linux Memory Implementation -----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Reid Spencer and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file provides the Linux specific implementation of various Memory
11 // management utilities
13 //===----------------------------------------------------------------------===//
15 // Include the generic unix implementation
16 #include "../Unix/Memory.cpp"
17 #include "llvm/System/Process.h"
23 //===----------------------------------------------------------------------===//
24 //=== WARNING: Implementation here must contain only Linux specific code
25 //=== and must not be generic UNIX code (see ../Unix/Memory.cpp)
26 //===----------------------------------------------------------------------===//
28 /// AllocateRWXMemory - Allocate a slab of memory with read/write/execute
29 /// permissions. This is typically used for JIT applications where we want
30 /// to emit code to the memory then jump to it. Getting this type of memory
31 /// is very OS specific.
33 MemoryBlock Memory::AllocateRWX(unsigned NumBytes) {
34 if (NumBytes == 0) return MemoryBlock();
36 static const long pageSize = Process::GetPageSize();
37 unsigned NumPages = (NumBytes+pageSize-1)/pageSize;
39 void *pa = mmap(0, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
40 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 0, 0);
41 if (pa == MAP_FAILED) {
43 strerror_r(errno, msg, MAXPATHLEN-1);
44 throw std::string("Can't allocate RWX Memory: ") + msg;
48 result.Size = NumPages*pageSize;
52 void Memory::ReleaseRWX(MemoryBlock& M) {
53 if (M.Address == 0 || M.Size == 0) return;
54 if (0 != munmap(M.Address, M.Size)) {
56 strerror_r(errno, msg, MAXPATHLEN-1);
57 throw std::string("Can't release RWX Memory: ") + msg;
63 // vim: sw=2 smartindent smarttab tw=80 autoindent expandtab