Avoid creating a redundant zero APInt.

[oota-llvm.git] / lib / System / Unix / Memory.inc

diff --git a/lib/System/Unix/Memory.inc b/lib/System/Unix/Memory.inc
index cc461f15dfc0d687ffb80d9853f9567d6d2dce0f..0b74f74f7b6e1bc8d55214e6b15ece5a4d5805a5 100644 (file)
--- a/lib/System/Unix/Memory.inc
+++ b/lib/System/Unix/Memory.inc
@@ -2,8 +2,8 @@
 // 
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by Reid Spencer and is distributed under the 
-// University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 // 
 //===----------------------------------------------------------------------===//
 //
@@ -12,9 +12,65 @@
 //===----------------------------------------------------------------------===//
 
 #include "Unix.h"
+#include "llvm/System/Process.h"
 
-namespace llvm {
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
 
+/// 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.
+///
+llvm::sys::MemoryBlock 
+llvm::sys::Memory::AllocateRWX(unsigned NumBytes, const MemoryBlock* NearBlock,
+                               std::string *ErrMsg) {
+  if (NumBytes == 0) return MemoryBlock();
+
+  unsigned pageSize = Process::GetPageSize();
+  unsigned NumPages = (NumBytes+pageSize-1)/pageSize;
+
+  int fd = -1;
+#ifdef NEED_DEV_ZERO_FOR_MMAP
+  static int zero_fd = open("/dev/zero", O_RDWR);
+  if (zero_fd == -1) {
+    MakeErrMsg(ErrMsg, "Can't open /dev/zero device");
+    return MemoryBlock();
+  }
+  fd = zero_fd;
+#endif
+
+  int flags = MAP_PRIVATE |
+#ifdef HAVE_MMAP_ANONYMOUS
+  MAP_ANONYMOUS
+#else
+  MAP_ANON
+#endif
+  ;
+
+  void* start = NearBlock ? (unsigned char*)NearBlock->base() + 
+                            NearBlock->size() : 0;
+
+  void *pa = ::mmap(start, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
+                    flags, fd, 0);
+  if (pa == MAP_FAILED) {
+    if (NearBlock) //Try again without a near hint
+      return AllocateRWX(NumBytes, 0);
+
+    MakeErrMsg(ErrMsg, "Can't allocate RWX Memory");
+    return MemoryBlock();
+  }
+  MemoryBlock result;
+  result.Address = pa;
+  result.Size = NumPages*pageSize;
+  return result;
+}
+
+bool llvm::sys::Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
+  if (M.Address == 0 || M.Size == 0) return false;
+  if (0 != ::munmap(M.Address, M.Size))
+    return MakeErrMsg(ErrMsg, "Can't release RWX Memory");
+  return false;
 }
 
-// vim: sw=2 smartindent smarttab tw=80 autoindent expandtab