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//===- Win32/Memory.cpp - Win32 Memory Implementation -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the Win32 specific implementation of various Memory
// management utilities
//
//===----------------------------------------------------------------------===//
#include "Windows.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Process.h"
namespace llvm {
using namespace sys;
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 specific code
//=== and must not be UNIX code
//===----------------------------------------------------------------------===//
MemoryBlock Memory::AllocateRWX(size_t NumBytes,
const MemoryBlock *NearBlock,
std::string *ErrMsg) {
if (NumBytes == 0) return MemoryBlock();
static const size_t pageSize = Process::GetPageSize();
size_t NumPages = (NumBytes+pageSize-1)/pageSize;
PVOID start = NearBlock ? static_cast<unsigned char *>(NearBlock->base()) +
NearBlock->size() : NULL;
void *pa = VirtualAlloc(start, NumPages*pageSize, MEM_RESERVE | MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
if (pa == NULL) {
if (NearBlock) {
// Try again without the NearBlock hint
return AllocateRWX(NumBytes, NULL, ErrMsg);
}
MakeErrMsg(ErrMsg, "Can't allocate RWX Memory: ");
return MemoryBlock();
}
MemoryBlock result;
result.Address = pa;
result.Size = NumPages*pageSize;
return result;
}
bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
if (M.Address == 0 || M.Size == 0) return false;
if (!VirtualFree(M.Address, 0, MEM_RELEASE))
return MakeErrMsg(ErrMsg, "Can't release RWX Memory: ");
return false;
}
static DWORD getProtection(const void *addr) {
MEMORY_BASIC_INFORMATION info;
if (sizeof(info) == ::VirtualQuery(addr, &info, sizeof(info))) {
return info.Protect;
}
return 0;
}
bool Memory::setWritable(MemoryBlock &M, std::string *ErrMsg) {
if (!setRangeWritable(M.Address, M.Size)) {
return MakeErrMsg(ErrMsg, "Cannot set memory to writeable: ");
}
return true;
}
bool Memory::setExecutable(MemoryBlock &M, std::string *ErrMsg) {
if (!setRangeExecutable(M.Address, M.Size)) {
return MakeErrMsg(ErrMsg, "Cannot set memory to executable: ");
}
return true;
}
bool Memory::setRangeWritable(const void *Addr, size_t Size) {
DWORD prot = getProtection(Addr);
if (!prot)
return false;
if (prot == PAGE_EXECUTE || prot == PAGE_EXECUTE_READ) {
prot = PAGE_EXECUTE_READWRITE;
} else if (prot == PAGE_NOACCESS || prot == PAGE_READONLY) {
prot = PAGE_READWRITE;
}
DWORD oldProt;
sys::Memory::InvalidateInstructionCache(Addr, Size);
return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt)
== TRUE;
}
bool Memory::setRangeExecutable(const void *Addr, size_t Size) {
DWORD prot = getProtection(Addr);
if (!prot)
return false;
if (prot == PAGE_NOACCESS) {
prot = PAGE_EXECUTE;
} else if (prot == PAGE_READONLY) {
prot = PAGE_EXECUTE_READ;
} else if (prot == PAGE_READWRITE) {
prot = PAGE_EXECUTE_READWRITE;
}
DWORD oldProt;
sys::Memory::InvalidateInstructionCache(Addr, Size);
return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt)
== TRUE;
}
}
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