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Add a new function for the JIT. libsupport is now the only library that

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includes mman.h

llvm-svn: 13870
This commit is contained in:
Chris Lattner 2004-05-28 00:59:40 +00:00
parent a691850f26
commit 2df71158fb
1 changed files with 53 additions and 1 deletions
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54
lib/Support/SystemUtils.cpp
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@ -12,13 +12,14 @@
//
//===----------------------------------------------------------------------===//
#define _POSIX_MAPPED_FILES
#include "Support/SystemUtils.h"
#include "Config/sys/types.h"
#include "Config/sys/stat.h"
#include "Config/fcntl.h"
#include "Config/sys/wait.h"
#include "Config/sys/mman.h"
#include "Config/unistd.h"
#include "Config/config.h"
#include <algorithm>
#include <fstream>
#include <iostream>
@ -268,3 +269,54 @@ int llvm::ExecWait(const char * const old_argv[],
// Otherwise, return failure.
return 1;
}
/// AllocateRWXMemory - Allocate a slab of memory with read/write/execute
/// permissions. This is typically used for JIT applications where we want
/// to emit code to the memory then jump to it. Getting this type of memory
/// is very OS specific.
///
void *llvm::AllocateRWXMemory(unsigned NumBytes) {
if (NumBytes == 0) return 0;
static const long pageSize = sysconf(_SC_PAGESIZE);
unsigned NumPages = (NumBytes+pageSize-1)/pageSize;
/* FIXME: This should use the proper autoconf flags */
#if defined(i386) || defined(__i386__) || defined(__x86__)
/* Linux and *BSD tend to have these flags named differently. */
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
# define MAP_ANONYMOUS MAP_ANON
#endif /* defined(MAP_ANON) && !defined(MAP_ANONYMOUS) */
#elif defined(sparc) || defined(__sparc__) || defined(__sparcv9)
/* nothing */
#else
std::cerr << "This architecture is not supported by the JIT!\n";
abort();
return 0;
#endif
#ifdef HAVE_MMAP
int fd = -1;
#if defined(__linux__)
fd = 0;
#endif
unsigned mmapFlags = MAP_PRIVATE|MAP_ANONYMOUS;
#ifdef MAP_NORESERVE
mmapFlags |= MAP_NORESERVE;
#endif
void *pa = mmap(0, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
mmapFlags, fd, 0);
if (pa == MAP_FAILED) {
perror("mmap");
abort();
}
return pa;
#else
std::cerr << "Do not know how to allocate mem for the JIT without mmap!\n";
abort();
return 0;
#endif
}