dvander@11: /*
dvander@11:  * Copyright (C) 2012 David Anderson
dvander@11:  *
dvander@11:  * This file is part of JITCraft.
dvander@11:  *
dvander@11:  * JITCraft is free software: you can redistribute it and/or modify it under
dvander@11:  * the terms of the GNU General Public License as published by the Free
dvander@11:  * Software Foundation, either version 3 of the License, or (at your option)
dvander@11:  * any later version.
dvander@11:  * 
dvander@11:  * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY
dvander@11:  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
dvander@11:  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
dvander@11:  *
dvander@11:  * You should have received a copy of the GNU General Public License along with
dvander@11:  * JITCraft. If not, see http://www.gnu.org/licenses/.
dvander@11:  */
dvander@11: 
dvander@11: // :TODO: move into utility-style include
dvander@11: #define WIN32_LEAN_AND_MEAN
dvander@11: #include <Windows.h>
dvander@11: #include "Platform.h"
dvander@11: 
dvander@11: using namespace jc;
dvander@11: 
dvander@11: static inline DWORD
dvander@11: ToProtBits(OS::Protection prot)
dvander@11: {
dvander@11:     switch (prot) {
dvander@11: 	  case OS::Prot_ReadWrite:
dvander@11:         return PAGE_READWRITE;
dvander@11:       case OS::Prot_ReadWriteExecute:
dvander@11:         return PAGE_EXECUTE_READWRITE;
dvander@11:       default:
dvander@11:         assert(prot == OS::Prot_ReadExecute);
dvander@11:         return PAGE_EXECUTE_READ;
dvander@11:     }
dvander@11: }
dvander@11: 
dvander@11: Address
dvander@11: OS::MapMemory(size_t amount, MapMode mode, Protection prot_)
dvander@11: {
dvander@11:     DWORD prot = ToProtBits(prot_);
dvander@11:     DWORD type = MEM_RESERVE;
dvander@11:     if (mode == Map_Commit)
dvander@11:         type |= MEM_COMMIT;
dvander@11: 
dvander@11:     return (Address)VirtualAlloc(NULL, amount, type, prot);
dvander@11: }
dvander@11: 
dvander@11: bool
dvander@11: OS::CommitMemory(Address address, size_t amount, Protection prot_)
dvander@11: {
dvander@11:     DWORD prot = ToProtBits(prot_);
dvander@11:     return !!VirtualAlloc(address, amount, MEM_COMMIT, prot);
dvander@11: }
dvander@11: 
dvander@11: void
dvander@11: OS::UnmapMemory(Address address, size_t size)
dvander@11: {
dvander@11:     VirtualFree(address, 0, MEM_RELEASE);
dvander@11: }
dvander@11: 
dvander@11: OS::AlignableMapping
dvander@11: OS::MapAlignedMemory(size_t amount, size_t alignment, MapMode mode)
dvander@11: {
dvander@11:     Address addr = MapMemory(amount, mode, OS::Prot_ReadWrite);
dvander@11:     if (!addr)
dvander@11:         return AlignableMapping(NULL, alignment, 0);
dvander@11: 
dvander@11:     if (!IsAligned(addr, alignment)) {
dvander@11:         UnmapMemory(addr, amount);
dvander@11: 
dvander@11:         // Try to grab the next available aligned address.
dvander@11:         addr = AlignedBase(addr, alignment);
dvander@11:         addr = MapMemoryAt(addr + alignment, amount, mode, OS::Prot_ReadWrite);
dvander@11:         while (!addr) {
dvander@11:             // Try to over-allocate to get the right region. This can race
dvander@11:             // with other threads; we expect this to be rare. If this turns
dvander@11:             // out to be a problem, the API is set up such that we can just
dvander@11:             // return two pointers: the base, and the aligned address into
dvander@11:             // the over-allocated region.
dvander@11:             addr = MapMemory(amount + alignment, mode, OS::Prot_ReadWrite);
dvander@11:             if (!addr)
dvander@11:                 return AlignableMapping(NULL, alignment, 0);
dvander@11:             UnmapMemory(addr, amount + alignment);
dvander@11:             addr = AlignedBase(addr, alignment);
dvander@11:             addr = MapMemoryAt(addr + alignment, amount, mode, OS::Prot_ReadWrite);
dvander@11:         }
dvander@11:     }
dvander@11: 
dvander@11:     return AlignableMapping(addr, alignment, amount);
dvander@11: }
dvander@11: 
dvander@11: Address
dvander@11: OS::MapMemoryAt(Address address, size_t amount, MapMode mode, Protection prot_)
dvander@11: {
dvander@11:     DWORD bits = ToProtBits(prot_);
dvander@11:     DWORD flags = MEM_RESERVE;
dvander@11:     if (mode == Map_Commit)
dvander@11:         flags |= MEM_COMMIT;
dvander@11: 
dvander@11:     Address x = (Address)VirtualAlloc((LPVOID)address, amount, flags, bits);
dvander@11:     if (!x) {
dvander@11:         DWORD err = GetLastError();
dvander@11:         return x;
dvander@11:     }
dvander@11:     return x;
dvander@11: }
dvander@11: 
dvander@11: void
dvander@11: OS::UnmapAlignedMemory(Address address, size_t size)
dvander@11: {
dvander@11:     OS::UnmapMemory(address, size);
dvander@11: }