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are allocated in the same buffer as the code, jump tables, etc. The default JIT memory manager does not handle buffer overflow well. I didn't introduce this and I'm not attempting to fix it here, but it is more likely to be hit now since we're putting more stuff in the buffer. This affects one test that I know of so far, MultiSource/Benchmarks/NPB-serial/is. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54442 91177308-0d34-0410-b5e6-96231b3b80d8
479 lines
18 KiB
C++
479 lines
18 KiB
C++
//===-- JITMemoryManager.cpp - Memory Allocator for JIT'd code ------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the DefaultJITMemoryManager class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/GlobalValue.h"
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#include "llvm/ExecutionEngine/JITMemoryManager.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/System/Memory.h"
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#include <map>
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#include <vector>
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#include <cassert>
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#include <cstdlib>
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#include <cstring>
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using namespace llvm;
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JITMemoryManager::~JITMemoryManager() {}
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//===----------------------------------------------------------------------===//
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// Memory Block Implementation.
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//===----------------------------------------------------------------------===//
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namespace {
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/// MemoryRangeHeader - For a range of memory, this is the header that we put
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/// on the block of memory. It is carefully crafted to be one word of memory.
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/// Allocated blocks have just this header, free'd blocks have FreeRangeHeader
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/// which starts with this.
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struct FreeRangeHeader;
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struct MemoryRangeHeader {
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/// ThisAllocated - This is true if this block is currently allocated. If
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/// not, this can be converted to a FreeRangeHeader.
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unsigned ThisAllocated : 1;
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/// PrevAllocated - Keep track of whether the block immediately before us is
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/// allocated. If not, the word immediately before this header is the size
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/// of the previous block.
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unsigned PrevAllocated : 1;
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/// BlockSize - This is the size in bytes of this memory block,
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/// including this header.
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uintptr_t BlockSize : (sizeof(intptr_t)*8 - 2);
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/// getBlockAfter - Return the memory block immediately after this one.
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///
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MemoryRangeHeader &getBlockAfter() const {
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return *(MemoryRangeHeader*)((char*)this+BlockSize);
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}
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/// getFreeBlockBefore - If the block before this one is free, return it,
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/// otherwise return null.
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FreeRangeHeader *getFreeBlockBefore() const {
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if (PrevAllocated) return 0;
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intptr_t PrevSize = ((intptr_t *)this)[-1];
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return (FreeRangeHeader*)((char*)this-PrevSize);
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}
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/// FreeBlock - Turn an allocated block into a free block, adjusting
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/// bits in the object headers, and adding an end of region memory block.
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FreeRangeHeader *FreeBlock(FreeRangeHeader *FreeList);
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/// TrimAllocationToSize - If this allocated block is significantly larger
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/// than NewSize, split it into two pieces (where the former is NewSize
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/// bytes, including the header), and add the new block to the free list.
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FreeRangeHeader *TrimAllocationToSize(FreeRangeHeader *FreeList,
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uint64_t NewSize);
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};
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/// FreeRangeHeader - For a memory block that isn't already allocated, this
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/// keeps track of the current block and has a pointer to the next free block.
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/// Free blocks are kept on a circularly linked list.
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struct FreeRangeHeader : public MemoryRangeHeader {
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FreeRangeHeader *Prev;
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FreeRangeHeader *Next;
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/// getMinBlockSize - Get the minimum size for a memory block. Blocks
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/// smaller than this size cannot be created.
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static unsigned getMinBlockSize() {
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return sizeof(FreeRangeHeader)+sizeof(intptr_t);
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}
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/// SetEndOfBlockSizeMarker - The word at the end of every free block is
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/// known to be the size of the free block. Set it for this block.
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void SetEndOfBlockSizeMarker() {
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void *EndOfBlock = (char*)this + BlockSize;
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((intptr_t *)EndOfBlock)[-1] = BlockSize;
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}
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FreeRangeHeader *RemoveFromFreeList() {
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assert(Next->Prev == this && Prev->Next == this && "Freelist broken!");
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Next->Prev = Prev;
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return Prev->Next = Next;
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}
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void AddToFreeList(FreeRangeHeader *FreeList) {
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Next = FreeList;
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Prev = FreeList->Prev;
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Prev->Next = this;
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Next->Prev = this;
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}
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/// GrowBlock - The block after this block just got deallocated. Merge it
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/// into the current block.
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void GrowBlock(uintptr_t NewSize);
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/// AllocateBlock - Mark this entire block allocated, updating freelists
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/// etc. This returns a pointer to the circular free-list.
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FreeRangeHeader *AllocateBlock();
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};
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}
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/// AllocateBlock - Mark this entire block allocated, updating freelists
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/// etc. This returns a pointer to the circular free-list.
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FreeRangeHeader *FreeRangeHeader::AllocateBlock() {
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assert(!ThisAllocated && !getBlockAfter().PrevAllocated &&
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"Cannot allocate an allocated block!");
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// Mark this block allocated.
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ThisAllocated = 1;
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getBlockAfter().PrevAllocated = 1;
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// Remove it from the free list.
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return RemoveFromFreeList();
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}
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/// FreeBlock - Turn an allocated block into a free block, adjusting
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/// bits in the object headers, and adding an end of region memory block.
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/// If possible, coalesce this block with neighboring blocks. Return the
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/// FreeRangeHeader to allocate from.
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FreeRangeHeader *MemoryRangeHeader::FreeBlock(FreeRangeHeader *FreeList) {
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MemoryRangeHeader *FollowingBlock = &getBlockAfter();
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assert(ThisAllocated && "This block is already allocated!");
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assert(FollowingBlock->PrevAllocated && "Flags out of sync!");
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FreeRangeHeader *FreeListToReturn = FreeList;
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// If the block after this one is free, merge it into this block.
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if (!FollowingBlock->ThisAllocated) {
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FreeRangeHeader &FollowingFreeBlock = *(FreeRangeHeader *)FollowingBlock;
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// "FreeList" always needs to be a valid free block. If we're about to
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// coalesce with it, update our notion of what the free list is.
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if (&FollowingFreeBlock == FreeList) {
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FreeList = FollowingFreeBlock.Next;
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FreeListToReturn = 0;
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assert(&FollowingFreeBlock != FreeList && "No tombstone block?");
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}
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FollowingFreeBlock.RemoveFromFreeList();
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// Include the following block into this one.
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BlockSize += FollowingFreeBlock.BlockSize;
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FollowingBlock = &FollowingFreeBlock.getBlockAfter();
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// Tell the block after the block we are coalescing that this block is
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// allocated.
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FollowingBlock->PrevAllocated = 1;
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}
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assert(FollowingBlock->ThisAllocated && "Missed coalescing?");
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if (FreeRangeHeader *PrevFreeBlock = getFreeBlockBefore()) {
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PrevFreeBlock->GrowBlock(PrevFreeBlock->BlockSize + BlockSize);
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return FreeListToReturn ? FreeListToReturn : PrevFreeBlock;
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}
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// Otherwise, mark this block free.
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FreeRangeHeader &FreeBlock = *(FreeRangeHeader*)this;
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FollowingBlock->PrevAllocated = 0;
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FreeBlock.ThisAllocated = 0;
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// Link this into the linked list of free blocks.
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FreeBlock.AddToFreeList(FreeList);
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// Add a marker at the end of the block, indicating the size of this free
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// block.
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FreeBlock.SetEndOfBlockSizeMarker();
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return FreeListToReturn ? FreeListToReturn : &FreeBlock;
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}
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/// GrowBlock - The block after this block just got deallocated. Merge it
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/// into the current block.
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void FreeRangeHeader::GrowBlock(uintptr_t NewSize) {
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assert(NewSize > BlockSize && "Not growing block?");
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BlockSize = NewSize;
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SetEndOfBlockSizeMarker();
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getBlockAfter().PrevAllocated = 0;
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}
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/// TrimAllocationToSize - If this allocated block is significantly larger
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/// than NewSize, split it into two pieces (where the former is NewSize
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/// bytes, including the header), and add the new block to the free list.
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FreeRangeHeader *MemoryRangeHeader::
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TrimAllocationToSize(FreeRangeHeader *FreeList, uint64_t NewSize) {
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assert(ThisAllocated && getBlockAfter().PrevAllocated &&
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"Cannot deallocate part of an allocated block!");
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// Don't allow blocks to be trimmed below minimum required size
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NewSize = std::max<uint64_t>(FreeRangeHeader::getMinBlockSize(), NewSize);
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// Round up size for alignment of header.
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unsigned HeaderAlign = __alignof(FreeRangeHeader);
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NewSize = (NewSize+ (HeaderAlign-1)) & ~(HeaderAlign-1);
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// Size is now the size of the block we will remove from the start of the
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// current block.
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assert(NewSize <= BlockSize &&
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"Allocating more space from this block than exists!");
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// If splitting this block will cause the remainder to be too small, do not
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// split the block.
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if (BlockSize <= NewSize+FreeRangeHeader::getMinBlockSize())
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return FreeList;
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// Otherwise, we splice the required number of bytes out of this block, form
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// a new block immediately after it, then mark this block allocated.
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MemoryRangeHeader &FormerNextBlock = getBlockAfter();
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// Change the size of this block.
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BlockSize = NewSize;
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// Get the new block we just sliced out and turn it into a free block.
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FreeRangeHeader &NewNextBlock = (FreeRangeHeader &)getBlockAfter();
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NewNextBlock.BlockSize = (char*)&FormerNextBlock - (char*)&NewNextBlock;
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NewNextBlock.ThisAllocated = 0;
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NewNextBlock.PrevAllocated = 1;
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NewNextBlock.SetEndOfBlockSizeMarker();
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FormerNextBlock.PrevAllocated = 0;
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NewNextBlock.AddToFreeList(FreeList);
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return &NewNextBlock;
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}
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//===----------------------------------------------------------------------===//
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// Memory Block Implementation.
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//===----------------------------------------------------------------------===//
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namespace {
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/// DefaultJITMemoryManager - Manage memory for the JIT code generation.
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/// This splits a large block of MAP_NORESERVE'd memory into two
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/// sections, one for function stubs, one for the functions themselves. We
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/// have to do this because we may need to emit a function stub while in the
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/// middle of emitting a function, and we don't know how large the function we
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/// are emitting is.
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class VISIBILITY_HIDDEN DefaultJITMemoryManager : public JITMemoryManager {
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std::vector<sys::MemoryBlock> Blocks; // Memory blocks allocated by the JIT
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FreeRangeHeader *FreeMemoryList; // Circular list of free blocks.
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// When emitting code into a memory block, this is the block.
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MemoryRangeHeader *CurBlock;
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unsigned char *CurStubPtr, *StubBase;
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unsigned char *GOTBase; // Target Specific reserved memory
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// Centralize memory block allocation.
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sys::MemoryBlock getNewMemoryBlock(unsigned size);
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std::map<const Function*, MemoryRangeHeader*> FunctionBlocks;
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std::map<const Function*, MemoryRangeHeader*> TableBlocks;
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public:
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DefaultJITMemoryManager();
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~DefaultJITMemoryManager();
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void AllocateGOT();
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unsigned char *allocateStub(const GlobalValue* F, unsigned StubSize,
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unsigned Alignment);
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/// startFunctionBody - When a function starts, allocate a block of free
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/// executable memory, returning a pointer to it and its actual size.
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unsigned char *startFunctionBody(const Function *F, uintptr_t &ActualSize) {
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CurBlock = FreeMemoryList;
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// Allocate the entire memory block.
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FreeMemoryList = FreeMemoryList->AllocateBlock();
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ActualSize = CurBlock->BlockSize-sizeof(MemoryRangeHeader);
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return (unsigned char *)(CurBlock+1);
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}
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/// endFunctionBody - The function F is now allocated, and takes the memory
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/// in the range [FunctionStart,FunctionEnd).
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void endFunctionBody(const Function *F, unsigned char *FunctionStart,
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unsigned char *FunctionEnd) {
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assert(FunctionEnd > FunctionStart);
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assert(FunctionStart == (unsigned char *)(CurBlock+1) &&
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"Mismatched function start/end!");
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uintptr_t BlockSize = FunctionEnd - (unsigned char *)CurBlock;
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FunctionBlocks[F] = CurBlock;
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// Release the memory at the end of this block that isn't needed.
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FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
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}
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/// startExceptionTable - Use startFunctionBody to allocate memory for the
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/// function's exception table.
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unsigned char* startExceptionTable(const Function* F,
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uintptr_t &ActualSize) {
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return startFunctionBody(F, ActualSize);
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}
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/// endExceptionTable - The exception table of F is now allocated,
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/// and takes the memory in the range [TableStart,TableEnd).
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void endExceptionTable(const Function *F, unsigned char *TableStart,
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unsigned char *TableEnd,
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unsigned char* FrameRegister) {
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assert(TableEnd > TableStart);
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assert(TableStart == (unsigned char *)(CurBlock+1) &&
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"Mismatched table start/end!");
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uintptr_t BlockSize = TableEnd - (unsigned char *)CurBlock;
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TableBlocks[F] = CurBlock;
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// Release the memory at the end of this block that isn't needed.
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FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
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}
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unsigned char *getGOTBase() const {
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return GOTBase;
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}
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/// deallocateMemForFunction - Deallocate all memory for the specified
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/// function body.
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void deallocateMemForFunction(const Function *F) {
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std::map<const Function*, MemoryRangeHeader*>::iterator
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I = FunctionBlocks.find(F);
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if (I == FunctionBlocks.end()) return;
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// Find the block that is allocated for this function.
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MemoryRangeHeader *MemRange = I->second;
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assert(MemRange->ThisAllocated && "Block isn't allocated!");
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// Fill the buffer with garbage!
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#ifndef NDEBUG
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memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange));
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#endif
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// Free the memory.
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FreeMemoryList = MemRange->FreeBlock(FreeMemoryList);
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// Finally, remove this entry from FunctionBlocks.
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FunctionBlocks.erase(I);
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I = TableBlocks.find(F);
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if (I == TableBlocks.end()) return;
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// Find the block that is allocated for this function.
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MemRange = I->second;
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assert(MemRange->ThisAllocated && "Block isn't allocated!");
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// Fill the buffer with garbage!
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#ifndef NDEBUG
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memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange));
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#endif
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// Free the memory.
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FreeMemoryList = MemRange->FreeBlock(FreeMemoryList);
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// Finally, remove this entry from TableBlocks.
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TableBlocks.erase(I);
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}
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};
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}
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DefaultJITMemoryManager::DefaultJITMemoryManager() {
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// Allocate a 16M block of memory for functions.
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sys::MemoryBlock MemBlock = getNewMemoryBlock(16 << 20);
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unsigned char *MemBase = static_cast<unsigned char*>(MemBlock.base());
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// Allocate stubs backwards from the base, allocate functions forward
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// from the base.
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StubBase = MemBase;
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CurStubPtr = MemBase + 512*1024; // Use 512k for stubs, working backwards.
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// We set up the memory chunk with 4 mem regions, like this:
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// [ START
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// [ Free #0 ] -> Large space to allocate functions from.
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// [ Allocated #1 ] -> Tiny space to separate regions.
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// [ Free #2 ] -> Tiny space so there is always at least 1 free block.
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// [ Allocated #3 ] -> Tiny space to prevent looking past end of block.
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// END ]
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//
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// The last three blocks are never deallocated or touched.
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// Add MemoryRangeHeader to the end of the memory region, indicating that
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// the space after the block of memory is allocated. This is block #3.
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MemoryRangeHeader *Mem3 = (MemoryRangeHeader*)(MemBase+MemBlock.size())-1;
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Mem3->ThisAllocated = 1;
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Mem3->PrevAllocated = 0;
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Mem3->BlockSize = 0;
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/// Add a tiny free region so that the free list always has one entry.
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FreeRangeHeader *Mem2 =
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(FreeRangeHeader *)(((char*)Mem3)-FreeRangeHeader::getMinBlockSize());
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Mem2->ThisAllocated = 0;
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Mem2->PrevAllocated = 1;
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Mem2->BlockSize = FreeRangeHeader::getMinBlockSize();
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Mem2->SetEndOfBlockSizeMarker();
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Mem2->Prev = Mem2; // Mem2 *is* the free list for now.
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Mem2->Next = Mem2;
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/// Add a tiny allocated region so that Mem2 is never coalesced away.
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MemoryRangeHeader *Mem1 = (MemoryRangeHeader*)Mem2-1;
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Mem1->ThisAllocated = 1;
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Mem1->PrevAllocated = 0;
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Mem1->BlockSize = (char*)Mem2 - (char*)Mem1;
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// Add a FreeRangeHeader to the start of the function body region, indicating
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// that the space is free. Mark the previous block allocated so we never look
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// at it.
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FreeRangeHeader *Mem0 = (FreeRangeHeader*)CurStubPtr;
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Mem0->ThisAllocated = 0;
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Mem0->PrevAllocated = 1;
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Mem0->BlockSize = (char*)Mem1-(char*)Mem0;
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Mem0->SetEndOfBlockSizeMarker();
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Mem0->AddToFreeList(Mem2);
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// Start out with the freelist pointing to Mem0.
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FreeMemoryList = Mem0;
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GOTBase = NULL;
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}
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void DefaultJITMemoryManager::AllocateGOT() {
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assert(GOTBase == 0 && "Cannot allocate the got multiple times");
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GOTBase = new unsigned char[sizeof(void*) * 8192];
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HasGOT = true;
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}
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DefaultJITMemoryManager::~DefaultJITMemoryManager() {
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for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
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sys::Memory::ReleaseRWX(Blocks[i]);
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delete[] GOTBase;
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Blocks.clear();
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}
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unsigned char *DefaultJITMemoryManager::allocateStub(const GlobalValue* F,
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unsigned StubSize,
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unsigned Alignment) {
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CurStubPtr -= StubSize;
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CurStubPtr = (unsigned char*)(((intptr_t)CurStubPtr) &
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~(intptr_t)(Alignment-1));
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if (CurStubPtr < StubBase) {
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// FIXME: allocate a new block
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fprintf(stderr, "JIT ran out of memory for function stubs!\n");
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abort();
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}
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return CurStubPtr;
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}
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sys::MemoryBlock DefaultJITMemoryManager::getNewMemoryBlock(unsigned size) {
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// Allocate a new block close to the last one.
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const sys::MemoryBlock *BOld = Blocks.empty() ? 0 : &Blocks.front();
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std::string ErrMsg;
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sys::MemoryBlock B = sys::Memory::AllocateRWX(size, BOld, &ErrMsg);
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if (B.base() == 0) {
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fprintf(stderr,
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"Allocation failed when allocating new memory in the JIT\n%s\n",
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ErrMsg.c_str());
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abort();
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}
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Blocks.push_back(B);
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return B;
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}
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JITMemoryManager *JITMemoryManager::CreateDefaultMemManager() {
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return new DefaultJITMemoryManager();
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}
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