922 lines
35 KiB
C++
922 lines
35 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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#define DEBUG_TYPE "jit"
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#include "llvm/ExecutionEngine/JITMemoryManager.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/GlobalValue.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/Memory.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/DynamicLibrary.h"
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#include "llvm/Config/config.h"
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#include <vector>
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#include <cassert>
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#include <climits>
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#include <cstring>
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#if defined(__linux__)
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#if defined(HAVE_SYS_STAT_H)
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#include <sys/stat.h>
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#endif
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#include <fcntl.h>
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#include <unistd.h>
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#endif
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using namespace llvm;
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STATISTIC(NumSlabs, "Number of slabs of memory allocated by the JIT");
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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)*CHAR_BIT - 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 free!");
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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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class DefaultJITMemoryManager;
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class JITSlabAllocator : public SlabAllocator {
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DefaultJITMemoryManager &JMM;
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public:
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JITSlabAllocator(DefaultJITMemoryManager &jmm) : JMM(jmm) { }
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virtual ~JITSlabAllocator() { }
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virtual MemSlab *Allocate(size_t Size);
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virtual void Deallocate(MemSlab *Slab);
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};
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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 DefaultJITMemoryManager : public JITMemoryManager {
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// Whether to poison freed memory.
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bool PoisonMemory;
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/// LastSlab - This points to the last slab allocated and is used as the
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/// NearBlock parameter to AllocateRWX so that we can attempt to lay out all
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/// stubs, data, and code contiguously in memory. In general, however, this
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/// is not possible because the NearBlock parameter is ignored on Windows
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/// platforms and even on Unix it works on a best-effort pasis.
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sys::MemoryBlock LastSlab;
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// Memory slabs allocated by the JIT. We refer to them as slabs so we don't
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// confuse them with the blocks of memory described above.
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std::vector<sys::MemoryBlock> CodeSlabs;
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JITSlabAllocator BumpSlabAllocator;
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BumpPtrAllocator StubAllocator;
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BumpPtrAllocator DataAllocator;
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// Circular list of free blocks.
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FreeRangeHeader *FreeMemoryList;
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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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uint8_t *GOTBase; // Target Specific reserved memory
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public:
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DefaultJITMemoryManager();
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~DefaultJITMemoryManager();
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/// allocateNewSlab - Allocates a new MemoryBlock and remembers it as the
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/// last slab it allocated, so that subsequent allocations follow it.
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sys::MemoryBlock allocateNewSlab(size_t size);
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/// DefaultCodeSlabSize - When we have to go map more memory, we allocate at
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/// least this much unless more is requested.
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static const size_t DefaultCodeSlabSize;
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/// DefaultSlabSize - Allocate data into slabs of this size unless we get
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/// an allocation above SizeThreshold.
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static const size_t DefaultSlabSize;
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/// DefaultSizeThreshold - For any allocation larger than this threshold, we
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/// should allocate a separate slab.
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static const size_t DefaultSizeThreshold;
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/// getPointerToNamedFunction - This method returns the address of the
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/// specified function by using the dlsym function call.
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virtual void *getPointerToNamedFunction(const std::string &Name,
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bool AbortOnFailure = true);
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void AllocateGOT();
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// Testing methods.
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virtual bool CheckInvariants(std::string &ErrorStr);
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size_t GetDefaultCodeSlabSize() { return DefaultCodeSlabSize; }
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size_t GetDefaultDataSlabSize() { return DefaultSlabSize; }
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size_t GetDefaultStubSlabSize() { return DefaultSlabSize; }
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unsigned GetNumCodeSlabs() { return CodeSlabs.size(); }
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unsigned GetNumDataSlabs() { return DataAllocator.GetNumSlabs(); }
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unsigned GetNumStubSlabs() { return StubAllocator.GetNumSlabs(); }
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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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uint8_t *startFunctionBody(const Function *F, uintptr_t &ActualSize) {
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FreeRangeHeader* candidateBlock = FreeMemoryList;
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FreeRangeHeader* head = FreeMemoryList;
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FreeRangeHeader* iter = head->Next;
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uintptr_t largest = candidateBlock->BlockSize;
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// Search for the largest free block
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while (iter != head) {
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if (iter->BlockSize > largest) {
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largest = iter->BlockSize;
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candidateBlock = iter;
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}
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iter = iter->Next;
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}
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largest = largest - sizeof(MemoryRangeHeader);
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// If this block isn't big enough for the allocation desired, allocate
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// another block of memory and add it to the free list.
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if (largest < ActualSize ||
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largest <= FreeRangeHeader::getMinBlockSize()) {
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DEBUG(dbgs() << "JIT: Allocating another slab of memory for function.");
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candidateBlock = allocateNewCodeSlab((size_t)ActualSize);
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}
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// Select this candidate block for allocation
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CurBlock = candidateBlock;
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// Allocate the entire memory block.
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FreeMemoryList = candidateBlock->AllocateBlock();
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ActualSize = CurBlock->BlockSize - sizeof(MemoryRangeHeader);
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return (uint8_t *)(CurBlock + 1);
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}
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/// allocateNewCodeSlab - Helper method to allocate a new slab of code
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/// memory from the OS and add it to the free list. Returns the new
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/// FreeRangeHeader at the base of the slab.
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FreeRangeHeader *allocateNewCodeSlab(size_t MinSize) {
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// If the user needs at least MinSize free memory, then we account for
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// two MemoryRangeHeaders: the one in the user's block, and the one at the
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// end of the slab.
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size_t PaddedMin = MinSize + 2 * sizeof(MemoryRangeHeader);
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size_t SlabSize = std::max(DefaultCodeSlabSize, PaddedMin);
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sys::MemoryBlock B = allocateNewSlab(SlabSize);
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CodeSlabs.push_back(B);
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char *MemBase = (char*)(B.base());
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// Put a tiny allocated block at the end of the memory chunk, so when
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// FreeBlock calls getBlockAfter it doesn't fall off the end.
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MemoryRangeHeader *EndBlock =
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(MemoryRangeHeader*)(MemBase + B.size()) - 1;
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EndBlock->ThisAllocated = 1;
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EndBlock->PrevAllocated = 0;
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EndBlock->BlockSize = sizeof(MemoryRangeHeader);
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// Start out with a vast new block of free memory.
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FreeRangeHeader *NewBlock = (FreeRangeHeader*)MemBase;
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NewBlock->ThisAllocated = 0;
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// Make sure getFreeBlockBefore doesn't look into unmapped memory.
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NewBlock->PrevAllocated = 1;
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NewBlock->BlockSize = (uintptr_t)EndBlock - (uintptr_t)NewBlock;
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NewBlock->SetEndOfBlockSizeMarker();
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NewBlock->AddToFreeList(FreeMemoryList);
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assert(NewBlock->BlockSize - sizeof(MemoryRangeHeader) >= MinSize &&
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"The block was too small!");
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return NewBlock;
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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, uint8_t *FunctionStart,
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uint8_t *FunctionEnd) {
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assert(FunctionEnd > FunctionStart);
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assert(FunctionStart == (uint8_t *)(CurBlock+1) &&
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"Mismatched function start/end!");
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uintptr_t BlockSize = FunctionEnd - (uint8_t *)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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/// allocateSpace - Allocate a memory block of the given size. This method
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/// cannot be called between calls to startFunctionBody and endFunctionBody.
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uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) {
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CurBlock = FreeMemoryList;
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FreeMemoryList = FreeMemoryList->AllocateBlock();
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uint8_t *result = (uint8_t *)(CurBlock + 1);
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if (Alignment == 0) Alignment = 1;
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result = (uint8_t*)(((intptr_t)result+Alignment-1) &
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~(intptr_t)(Alignment-1));
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uintptr_t BlockSize = result + Size - (uint8_t *)CurBlock;
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FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
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return result;
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}
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/// allocateStub - Allocate memory for a function stub.
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uint8_t *allocateStub(const GlobalValue* F, unsigned StubSize,
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unsigned Alignment) {
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return (uint8_t*)StubAllocator.Allocate(StubSize, Alignment);
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}
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/// allocateGlobal - Allocate memory for a global.
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uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) {
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return (uint8_t*)DataAllocator.Allocate(Size, Alignment);
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}
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/// allocateCodeSection - Allocate memory for a code section.
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uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
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unsigned SectionID) {
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// FIXME: Alignement handling.
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FreeRangeHeader* candidateBlock = FreeMemoryList;
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FreeRangeHeader* head = FreeMemoryList;
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FreeRangeHeader* iter = head->Next;
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uintptr_t largest = candidateBlock->BlockSize;
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// Search for the largest free block.
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while (iter != head) {
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if (iter->BlockSize > largest) {
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largest = iter->BlockSize;
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candidateBlock = iter;
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}
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iter = iter->Next;
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}
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largest = largest - sizeof(MemoryRangeHeader);
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// If this block isn't big enough for the allocation desired, allocate
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// another block of memory and add it to the free list.
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if (largest < Size || largest <= FreeRangeHeader::getMinBlockSize()) {
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DEBUG(dbgs() << "JIT: Allocating another slab of memory for function.");
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candidateBlock = allocateNewCodeSlab((size_t)Size);
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}
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// Select this candidate block for allocation
|
|
CurBlock = candidateBlock;
|
|
|
|
// Allocate the entire memory block.
|
|
FreeMemoryList = candidateBlock->AllocateBlock();
|
|
// Release the memory at the end of this block that isn't needed.
|
|
FreeMemoryList = CurBlock->TrimAllocationToSize(FreeMemoryList, Size);
|
|
return (uint8_t *)(CurBlock + 1);
|
|
}
|
|
|
|
/// allocateDataSection - Allocate memory for a data section.
|
|
uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
|
|
unsigned SectionID) {
|
|
return (uint8_t*)DataAllocator.Allocate(Size, Alignment);
|
|
}
|
|
|
|
/// startExceptionTable - Use startFunctionBody to allocate memory for the
|
|
/// function's exception table.
|
|
uint8_t* startExceptionTable(const Function* F, uintptr_t &ActualSize) {
|
|
return startFunctionBody(F, ActualSize);
|
|
}
|
|
|
|
/// endExceptionTable - The exception table of F is now allocated,
|
|
/// and takes the memory in the range [TableStart,TableEnd).
|
|
void endExceptionTable(const Function *F, uint8_t *TableStart,
|
|
uint8_t *TableEnd, uint8_t* FrameRegister) {
|
|
assert(TableEnd > TableStart);
|
|
assert(TableStart == (uint8_t *)(CurBlock+1) &&
|
|
"Mismatched table start/end!");
|
|
|
|
uintptr_t BlockSize = TableEnd - (uint8_t *)CurBlock;
|
|
|
|
// Release the memory at the end of this block that isn't needed.
|
|
FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
|
|
}
|
|
|
|
uint8_t *getGOTBase() const {
|
|
return GOTBase;
|
|
}
|
|
|
|
void deallocateBlock(void *Block) {
|
|
// Find the block that is allocated for this function.
|
|
MemoryRangeHeader *MemRange = static_cast<MemoryRangeHeader*>(Block) - 1;
|
|
assert(MemRange->ThisAllocated && "Block isn't allocated!");
|
|
|
|
// Fill the buffer with garbage!
|
|
if (PoisonMemory) {
|
|
memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange));
|
|
}
|
|
|
|
// Free the memory.
|
|
FreeMemoryList = MemRange->FreeBlock(FreeMemoryList);
|
|
}
|
|
|
|
/// deallocateFunctionBody - Deallocate all memory for the specified
|
|
/// function body.
|
|
void deallocateFunctionBody(void *Body) {
|
|
if (Body) deallocateBlock(Body);
|
|
}
|
|
|
|
/// deallocateExceptionTable - Deallocate memory for the specified
|
|
/// exception table.
|
|
void deallocateExceptionTable(void *ET) {
|
|
if (ET) deallocateBlock(ET);
|
|
}
|
|
|
|
/// setMemoryWritable - When code generation is in progress,
|
|
/// the code pages may need permissions changed.
|
|
void setMemoryWritable()
|
|
{
|
|
for (unsigned i = 0, e = CodeSlabs.size(); i != e; ++i)
|
|
sys::Memory::setWritable(CodeSlabs[i]);
|
|
}
|
|
/// setMemoryExecutable - When code generation is done and we're ready to
|
|
/// start execution, the code pages may need permissions changed.
|
|
void setMemoryExecutable()
|
|
{
|
|
for (unsigned i = 0, e = CodeSlabs.size(); i != e; ++i)
|
|
sys::Memory::setExecutable(CodeSlabs[i]);
|
|
}
|
|
|
|
/// setPoisonMemory - Controls whether we write garbage over freed memory.
|
|
///
|
|
void setPoisonMemory(bool poison) {
|
|
PoisonMemory = poison;
|
|
}
|
|
};
|
|
}
|
|
|
|
MemSlab *JITSlabAllocator::Allocate(size_t Size) {
|
|
sys::MemoryBlock B = JMM.allocateNewSlab(Size);
|
|
MemSlab *Slab = (MemSlab*)B.base();
|
|
Slab->Size = B.size();
|
|
Slab->NextPtr = 0;
|
|
return Slab;
|
|
}
|
|
|
|
void JITSlabAllocator::Deallocate(MemSlab *Slab) {
|
|
sys::MemoryBlock B(Slab, Slab->Size);
|
|
sys::Memory::ReleaseRWX(B);
|
|
}
|
|
|
|
DefaultJITMemoryManager::DefaultJITMemoryManager()
|
|
:
|
|
#ifdef NDEBUG
|
|
PoisonMemory(false),
|
|
#else
|
|
PoisonMemory(true),
|
|
#endif
|
|
LastSlab(0, 0),
|
|
BumpSlabAllocator(*this),
|
|
StubAllocator(DefaultSlabSize, DefaultSizeThreshold, BumpSlabAllocator),
|
|
DataAllocator(DefaultSlabSize, DefaultSizeThreshold, BumpSlabAllocator) {
|
|
|
|
// Allocate space for code.
|
|
sys::MemoryBlock MemBlock = allocateNewSlab(DefaultCodeSlabSize);
|
|
CodeSlabs.push_back(MemBlock);
|
|
uint8_t *MemBase = (uint8_t*)MemBlock.base();
|
|
|
|
// We set up the memory chunk with 4 mem regions, like this:
|
|
// [ START
|
|
// [ Free #0 ] -> Large space to allocate functions from.
|
|
// [ Allocated #1 ] -> Tiny space to separate regions.
|
|
// [ Free #2 ] -> Tiny space so there is always at least 1 free block.
|
|
// [ Allocated #3 ] -> Tiny space to prevent looking past end of block.
|
|
// END ]
|
|
//
|
|
// The last three blocks are never deallocated or touched.
|
|
|
|
// Add MemoryRangeHeader to the end of the memory region, indicating that
|
|
// the space after the block of memory is allocated. This is block #3.
|
|
MemoryRangeHeader *Mem3 = (MemoryRangeHeader*)(MemBase+MemBlock.size())-1;
|
|
Mem3->ThisAllocated = 1;
|
|
Mem3->PrevAllocated = 0;
|
|
Mem3->BlockSize = sizeof(MemoryRangeHeader);
|
|
|
|
/// Add a tiny free region so that the free list always has one entry.
|
|
FreeRangeHeader *Mem2 =
|
|
(FreeRangeHeader *)(((char*)Mem3)-FreeRangeHeader::getMinBlockSize());
|
|
Mem2->ThisAllocated = 0;
|
|
Mem2->PrevAllocated = 1;
|
|
Mem2->BlockSize = FreeRangeHeader::getMinBlockSize();
|
|
Mem2->SetEndOfBlockSizeMarker();
|
|
Mem2->Prev = Mem2; // Mem2 *is* the free list for now.
|
|
Mem2->Next = Mem2;
|
|
|
|
/// Add a tiny allocated region so that Mem2 is never coalesced away.
|
|
MemoryRangeHeader *Mem1 = (MemoryRangeHeader*)Mem2-1;
|
|
Mem1->ThisAllocated = 1;
|
|
Mem1->PrevAllocated = 0;
|
|
Mem1->BlockSize = sizeof(MemoryRangeHeader);
|
|
|
|
// Add a FreeRangeHeader to the start of the function body region, indicating
|
|
// that the space is free. Mark the previous block allocated so we never look
|
|
// at it.
|
|
FreeRangeHeader *Mem0 = (FreeRangeHeader*)MemBase;
|
|
Mem0->ThisAllocated = 0;
|
|
Mem0->PrevAllocated = 1;
|
|
Mem0->BlockSize = (char*)Mem1-(char*)Mem0;
|
|
Mem0->SetEndOfBlockSizeMarker();
|
|
Mem0->AddToFreeList(Mem2);
|
|
|
|
// Start out with the freelist pointing to Mem0.
|
|
FreeMemoryList = Mem0;
|
|
|
|
GOTBase = NULL;
|
|
}
|
|
|
|
void DefaultJITMemoryManager::AllocateGOT() {
|
|
assert(GOTBase == 0 && "Cannot allocate the got multiple times");
|
|
GOTBase = new uint8_t[sizeof(void*) * 8192];
|
|
HasGOT = true;
|
|
}
|
|
|
|
DefaultJITMemoryManager::~DefaultJITMemoryManager() {
|
|
for (unsigned i = 0, e = CodeSlabs.size(); i != e; ++i)
|
|
sys::Memory::ReleaseRWX(CodeSlabs[i]);
|
|
|
|
delete[] GOTBase;
|
|
}
|
|
|
|
sys::MemoryBlock DefaultJITMemoryManager::allocateNewSlab(size_t size) {
|
|
// Allocate a new block close to the last one.
|
|
std::string ErrMsg;
|
|
sys::MemoryBlock *LastSlabPtr = LastSlab.base() ? &LastSlab : 0;
|
|
sys::MemoryBlock B = sys::Memory::AllocateRWX(size, LastSlabPtr, &ErrMsg);
|
|
if (B.base() == 0) {
|
|
report_fatal_error("Allocation failed when allocating new memory in the"
|
|
" JIT\n" + Twine(ErrMsg));
|
|
}
|
|
LastSlab = B;
|
|
++NumSlabs;
|
|
// Initialize the slab to garbage when debugging.
|
|
if (PoisonMemory) {
|
|
memset(B.base(), 0xCD, B.size());
|
|
}
|
|
return B;
|
|
}
|
|
|
|
/// CheckInvariants - For testing only. Return "" if all internal invariants
|
|
/// are preserved, and a helpful error message otherwise. For free and
|
|
/// allocated blocks, make sure that adding BlockSize gives a valid block.
|
|
/// For free blocks, make sure they're in the free list and that their end of
|
|
/// block size marker is correct. This function should return an error before
|
|
/// accessing bad memory. This function is defined here instead of in
|
|
/// JITMemoryManagerTest.cpp so that we don't have to expose all of the
|
|
/// implementation details of DefaultJITMemoryManager.
|
|
bool DefaultJITMemoryManager::CheckInvariants(std::string &ErrorStr) {
|
|
raw_string_ostream Err(ErrorStr);
|
|
|
|
// Construct a the set of FreeRangeHeader pointers so we can query it
|
|
// efficiently.
|
|
llvm::SmallPtrSet<MemoryRangeHeader*, 16> FreeHdrSet;
|
|
FreeRangeHeader* FreeHead = FreeMemoryList;
|
|
FreeRangeHeader* FreeRange = FreeHead;
|
|
|
|
do {
|
|
// Check that the free range pointer is in the blocks we've allocated.
|
|
bool Found = false;
|
|
for (std::vector<sys::MemoryBlock>::iterator I = CodeSlabs.begin(),
|
|
E = CodeSlabs.end(); I != E && !Found; ++I) {
|
|
char *Start = (char*)I->base();
|
|
char *End = Start + I->size();
|
|
Found = (Start <= (char*)FreeRange && (char*)FreeRange < End);
|
|
}
|
|
if (!Found) {
|
|
Err << "Corrupt free list; points to " << FreeRange;
|
|
return false;
|
|
}
|
|
|
|
if (FreeRange->Next->Prev != FreeRange) {
|
|
Err << "Next and Prev pointers do not match.";
|
|
return false;
|
|
}
|
|
|
|
// Otherwise, add it to the set.
|
|
FreeHdrSet.insert(FreeRange);
|
|
FreeRange = FreeRange->Next;
|
|
} while (FreeRange != FreeHead);
|
|
|
|
// Go over each block, and look at each MemoryRangeHeader.
|
|
for (std::vector<sys::MemoryBlock>::iterator I = CodeSlabs.begin(),
|
|
E = CodeSlabs.end(); I != E; ++I) {
|
|
char *Start = (char*)I->base();
|
|
char *End = Start + I->size();
|
|
|
|
// Check each memory range.
|
|
for (MemoryRangeHeader *Hdr = (MemoryRangeHeader*)Start, *LastHdr = NULL;
|
|
Start <= (char*)Hdr && (char*)Hdr < End;
|
|
Hdr = &Hdr->getBlockAfter()) {
|
|
if (Hdr->ThisAllocated == 0) {
|
|
// Check that this range is in the free list.
|
|
if (!FreeHdrSet.count(Hdr)) {
|
|
Err << "Found free header at " << Hdr << " that is not in free list.";
|
|
return false;
|
|
}
|
|
|
|
// Now make sure the size marker at the end of the block is correct.
|
|
uintptr_t *Marker = ((uintptr_t*)&Hdr->getBlockAfter()) - 1;
|
|
if (!(Start <= (char*)Marker && (char*)Marker < End)) {
|
|
Err << "Block size in header points out of current MemoryBlock.";
|
|
return false;
|
|
}
|
|
if (Hdr->BlockSize != *Marker) {
|
|
Err << "End of block size marker (" << *Marker << ") "
|
|
<< "and BlockSize (" << Hdr->BlockSize << ") don't match.";
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (LastHdr && LastHdr->ThisAllocated != Hdr->PrevAllocated) {
|
|
Err << "Hdr->PrevAllocated (" << Hdr->PrevAllocated << ") != "
|
|
<< "LastHdr->ThisAllocated (" << LastHdr->ThisAllocated << ")";
|
|
return false;
|
|
} else if (!LastHdr && !Hdr->PrevAllocated) {
|
|
Err << "The first header should have PrevAllocated true.";
|
|
return false;
|
|
}
|
|
|
|
// Remember the last header.
|
|
LastHdr = Hdr;
|
|
}
|
|
}
|
|
|
|
// All invariants are preserved.
|
|
return true;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// getPointerToNamedFunction() implementation.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// AtExitHandlers - List of functions to call when the program exits,
|
|
// registered with the atexit() library function.
|
|
static std::vector<void (*)()> AtExitHandlers;
|
|
|
|
/// runAtExitHandlers - Run any functions registered by the program's
|
|
/// calls to atexit(3), which we intercept and store in
|
|
/// AtExitHandlers.
|
|
///
|
|
static void runAtExitHandlers() {
|
|
while (!AtExitHandlers.empty()) {
|
|
void (*Fn)() = AtExitHandlers.back();
|
|
AtExitHandlers.pop_back();
|
|
Fn();
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Function stubs that are invoked instead of certain library calls
|
|
//
|
|
// Force the following functions to be linked in to anything that uses the
|
|
// JIT. This is a hack designed to work around the all-too-clever Glibc
|
|
// strategy of making these functions work differently when inlined vs. when
|
|
// not inlined, and hiding their real definitions in a separate archive file
|
|
// that the dynamic linker can't see. For more info, search for
|
|
// 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
|
|
#if defined(__linux__)
|
|
/* stat functions are redirecting to __xstat with a version number. On x86-64
|
|
* linking with libc_nonshared.a and -Wl,--export-dynamic doesn't make 'stat'
|
|
* available as an exported symbol, so we have to add it explicitly.
|
|
*/
|
|
namespace {
|
|
class StatSymbols {
|
|
public:
|
|
StatSymbols() {
|
|
sys::DynamicLibrary::AddSymbol("stat", (void*)(intptr_t)stat);
|
|
sys::DynamicLibrary::AddSymbol("fstat", (void*)(intptr_t)fstat);
|
|
sys::DynamicLibrary::AddSymbol("lstat", (void*)(intptr_t)lstat);
|
|
sys::DynamicLibrary::AddSymbol("stat64", (void*)(intptr_t)stat64);
|
|
sys::DynamicLibrary::AddSymbol("\x1stat64", (void*)(intptr_t)stat64);
|
|
sys::DynamicLibrary::AddSymbol("\x1open64", (void*)(intptr_t)open64);
|
|
sys::DynamicLibrary::AddSymbol("\x1lseek64", (void*)(intptr_t)lseek64);
|
|
sys::DynamicLibrary::AddSymbol("fstat64", (void*)(intptr_t)fstat64);
|
|
sys::DynamicLibrary::AddSymbol("lstat64", (void*)(intptr_t)lstat64);
|
|
sys::DynamicLibrary::AddSymbol("atexit", (void*)(intptr_t)atexit);
|
|
sys::DynamicLibrary::AddSymbol("mknod", (void*)(intptr_t)mknod);
|
|
}
|
|
};
|
|
}
|
|
static StatSymbols initStatSymbols;
|
|
#endif // __linux__
|
|
|
|
// jit_exit - Used to intercept the "exit" library call.
|
|
static void jit_exit(int Status) {
|
|
runAtExitHandlers(); // Run atexit handlers...
|
|
exit(Status);
|
|
}
|
|
|
|
// jit_atexit - Used to intercept the "atexit" library call.
|
|
static int jit_atexit(void (*Fn)()) {
|
|
AtExitHandlers.push_back(Fn); // Take note of atexit handler...
|
|
return 0; // Always successful
|
|
}
|
|
|
|
static int jit_noop() {
|
|
return 0;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
/// getPointerToNamedFunction - This method returns the address of the specified
|
|
/// function by using the dynamic loader interface. As such it is only useful
|
|
/// for resolving library symbols, not code generated symbols.
|
|
///
|
|
void *DefaultJITMemoryManager::getPointerToNamedFunction(const std::string &Name,
|
|
bool AbortOnFailure) {
|
|
// Check to see if this is one of the functions we want to intercept. Note,
|
|
// we cast to intptr_t here to silence a -pedantic warning that complains
|
|
// about casting a function pointer to a normal pointer.
|
|
if (Name == "exit") return (void*)(intptr_t)&jit_exit;
|
|
if (Name == "atexit") return (void*)(intptr_t)&jit_atexit;
|
|
|
|
// We should not invoke parent's ctors/dtors from generated main()!
|
|
// On Mingw and Cygwin, the symbol __main is resolved to
|
|
// callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
|
|
// (and register wrong callee's dtors with atexit(3)).
|
|
// We expect ExecutionEngine::runStaticConstructorsDestructors()
|
|
// is called before ExecutionEngine::runFunctionAsMain() is called.
|
|
if (Name == "__main") return (void*)(intptr_t)&jit_noop;
|
|
|
|
const char *NameStr = Name.c_str();
|
|
// If this is an asm specifier, skip the sentinal.
|
|
if (NameStr[0] == 1) ++NameStr;
|
|
|
|
// If it's an external function, look it up in the process image...
|
|
void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
|
|
if (Ptr) return Ptr;
|
|
|
|
// If it wasn't found and if it starts with an underscore ('_') character,
|
|
// try again without the underscore.
|
|
if (NameStr[0] == '_') {
|
|
Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr+1);
|
|
if (Ptr) return Ptr;
|
|
}
|
|
|
|
// Darwin/PPC adds $LDBLStub suffixes to various symbols like printf. These
|
|
// are references to hidden visibility symbols that dlsym cannot resolve.
|
|
// If we have one of these, strip off $LDBLStub and try again.
|
|
#if defined(__APPLE__) && defined(__ppc__)
|
|
if (Name.size() > 9 && Name[Name.size()-9] == '$' &&
|
|
memcmp(&Name[Name.size()-8], "LDBLStub", 8) == 0) {
|
|
// First try turning $LDBLStub into $LDBL128. If that fails, strip it off.
|
|
// This mirrors logic in libSystemStubs.a.
|
|
std::string Prefix = std::string(Name.begin(), Name.end()-9);
|
|
if (void *Ptr = getPointerToNamedFunction(Prefix+"$LDBL128", false))
|
|
return Ptr;
|
|
if (void *Ptr = getPointerToNamedFunction(Prefix, false))
|
|
return Ptr;
|
|
}
|
|
#endif
|
|
|
|
if (AbortOnFailure) {
|
|
report_fatal_error("Program used external function '"+Name+
|
|
"' which could not be resolved!");
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
|
|
JITMemoryManager *JITMemoryManager::CreateDefaultMemManager() {
|
|
return new DefaultJITMemoryManager();
|
|
}
|
|
|
|
// Allocate memory for code in 512K slabs.
|
|
const size_t DefaultJITMemoryManager::DefaultCodeSlabSize = 512 * 1024;
|
|
|
|
// Allocate globals and stubs in slabs of 64K. (probably 16 pages)
|
|
const size_t DefaultJITMemoryManager::DefaultSlabSize = 64 * 1024;
|
|
|
|
// Waste at most 16K at the end of each bump slab. (probably 4 pages)
|
|
const size_t DefaultJITMemoryManager::DefaultSizeThreshold = 16 * 1024;
|