1//===- Win32/Memory.cpp - Win32 Memory Implementation -----------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file provides the Win32 specific implementation of various Memory 11// management utilities 12// 13//===----------------------------------------------------------------------===// 14 15#include "Windows.h" 16#include "llvm/Support/DataTypes.h" 17#include "llvm/Support/Process.h" 18 19namespace llvm { 20using namespace sys; 21 22//===----------------------------------------------------------------------===// 23//=== WARNING: Implementation here must contain only Win32 specific code 24//=== and must not be UNIX code 25//===----------------------------------------------------------------------===// 26 27MemoryBlock Memory::AllocateRWX(size_t NumBytes, 28 const MemoryBlock *NearBlock, 29 std::string *ErrMsg) { 30 if (NumBytes == 0) return MemoryBlock(); 31 32 static const size_t pageSize = Process::GetPageSize(); 33 size_t NumPages = (NumBytes+pageSize-1)/pageSize; 34 35 PVOID start = NearBlock ? static_cast<unsigned char *>(NearBlock->base()) + 36 NearBlock->size() : NULL; 37 38 void *pa = VirtualAlloc(start, NumPages*pageSize, MEM_RESERVE | MEM_COMMIT, 39 PAGE_EXECUTE_READWRITE); 40 if (pa == NULL) { 41 if (NearBlock) { 42 // Try again without the NearBlock hint 43 return AllocateRWX(NumBytes, NULL, ErrMsg); 44 } 45 MakeErrMsg(ErrMsg, "Can't allocate RWX Memory: "); 46 return MemoryBlock(); 47 } 48 49 MemoryBlock result; 50 result.Address = pa; 51 result.Size = NumPages*pageSize; 52 return result; 53} 54 55bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) { 56 if (M.Address == 0 || M.Size == 0) return false; 57 if (!VirtualFree(M.Address, 0, MEM_RELEASE)) 58 return MakeErrMsg(ErrMsg, "Can't release RWX Memory: "); 59 return false; 60} 61 62static DWORD getProtection(const void *addr) { 63 MEMORY_BASIC_INFORMATION info; 64 if (sizeof(info) == ::VirtualQuery(addr, &info, sizeof(info))) { 65 return info.Protect; 66 } 67 return 0; 68} 69 70bool Memory::setWritable(MemoryBlock &M, std::string *ErrMsg) { 71 if (!setRangeWritable(M.Address, M.Size)) { 72 return MakeErrMsg(ErrMsg, "Cannot set memory to writeable: "); 73 } 74 return true; 75} 76 77bool Memory::setExecutable(MemoryBlock &M, std::string *ErrMsg) { 78 if (!setRangeExecutable(M.Address, M.Size)) { 79 return MakeErrMsg(ErrMsg, "Cannot set memory to executable: "); 80 } 81 return true; 82} 83 84bool Memory::setRangeWritable(const void *Addr, size_t Size) { 85 DWORD prot = getProtection(Addr); 86 if (!prot) 87 return false; 88 89 if (prot == PAGE_EXECUTE || prot == PAGE_EXECUTE_READ) { 90 prot = PAGE_EXECUTE_READWRITE; 91 } else if (prot == PAGE_NOACCESS || prot == PAGE_READONLY) { 92 prot = PAGE_READWRITE; 93 } 94 95 DWORD oldProt; 96 sys::Memory::InvalidateInstructionCache(Addr, Size); 97 return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt) 98 == TRUE; 99} 100 101bool Memory::setRangeExecutable(const void *Addr, size_t Size) { 102 DWORD prot = getProtection(Addr); 103 if (!prot) 104 return false; 105 106 if (prot == PAGE_NOACCESS) { 107 prot = PAGE_EXECUTE; 108 } else if (prot == PAGE_READONLY) { 109 prot = PAGE_EXECUTE_READ; 110 } else if (prot == PAGE_READWRITE) { 111 prot = PAGE_EXECUTE_READWRITE; 112 } 113 114 DWORD oldProt; 115 sys::Memory::InvalidateInstructionCache(Addr, Size); 116 return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt) 117 == TRUE; 118} 119 120} 121