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split the JIT memory management code out from the main JIT logic into its

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own JITMemoryManager interface.  There is no functionality change with 
this patch.

llvm-svn: 44640
This commit is contained in:
Chris Lattner 2007-12-05 23:39:57 +00:00
parent e3f1487574
commit 3043dc44cd
4 changed files with 552 additions and 413 deletions
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4
include/llvm/ExecutionEngine/JIT.h
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@ -12,8 +12,8 @@
//
//===----------------------------------------------------------------------===//
#ifndef EXECUTION_ENGINE_JIT_H
#define EXECUTION_ENGINE_JIT_H
#ifndef LLVM_EXECUTION_ENGINE_JIT_H
#define LLVM_EXECUTION_ENGINE_JIT_H
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include <cstdlib>

96
include/llvm/ExecutionEngine/JITMemoryManager.h Normal file
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@ -0,0 +1,96 @@
//===-- JITMemoryManager.h - Interface JIT uses to Allocate Mem -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the JITMemoryManagerInterface
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTION_ENGINE_JIT_H
#define LLVM_EXECUTION_ENGINE_JIT_H
#include "llvm/Support/DataTypes.h"
namespace llvm {
class Function;
/// JITMemoryManager - This interface is used by the JIT to allocate and manage
/// memory for the code generated by the JIT. This can be reimplemented by
/// clients that have a strong desire to control how the layout of JIT'd memory
/// works.
class JITMemoryManager {
protected:
bool HasGOT;
public:
JITMemoryManager() : HasGOT(false) {}
virtual ~JITMemoryManager();
/// CreateDefaultMemManager - This is used to create the default
/// JIT Memory Manager if the client does not provide one to the JIT.
static JITMemoryManager *CreateDefaultMemManager();
//===--------------------------------------------------------------------===//
// Global Offset Table Management
//===--------------------------------------------------------------------===//
/// AllocateGOT - If the current table requires a Global Offset Table, this
/// method is invoked to allocate it. This method is required to set HasGOT
/// to true.
virtual void AllocateGOT() = 0;
/// isManagingGOT - Return true if the AllocateGOT method is called.
///
bool isManagingGOT() const {
return HasGOT;
}
/// getGOTBase - If this is managing a Global Offset Table, this method should
/// return a pointer to its base.
virtual unsigned char *getGOTBase() const = 0;
//===--------------------------------------------------------------------===//
// Main Allocation Functions
//===--------------------------------------------------------------------===//
/// startFunctionBody - When we start JITing a function, the JIT calls this
/// method to allocate a block of free RWX memory, which returns a pointer to
/// it. The JIT doesn't know ahead of time how much space it will need to
/// emit the function, so it doesn't pass in the size. Instead, this method
/// is required to pass back a "valid size". The JIT will be careful to not
/// write more than the returned ActualSize bytes of memory.
virtual unsigned char *startFunctionBody(const Function *F,
uintptr_t &ActualSize) = 0;
/// allocateStub - This method is called by the JIT to allocate space for a
/// function stub (used to handle limited branch displacements) while it is
/// JIT compiling a function. For example, if foo calls bar, and if bar
/// either needs to be lazily compiled or is a native function that exists too
/// far away from the call site to work, this method will be used to make a
/// thunk for it. The stub should be "close" to the current function body,
/// but should not be included in the 'actualsize' returned by
/// startFunctionBody.
virtual unsigned char *allocateStub(unsigned StubSize, unsigned Alignment) =0;
/// endFunctionBody - This method is called when the JIT is done codegen'ing
/// the specified function. At this point we know the size of the JIT
/// compiled function. This passes in FunctionStart (which was returned by
/// the startFunctionBody method) and FunctionEnd which is a pointer to the
/// actual end of the function. This method should mark the space allocated
/// and remember where it is in case the client wants to deallocate it.
virtual void endFunctionBody(const Function *F, unsigned char *FunctionStart,
unsigned char *FunctionEnd) = 0;
/// deallocateMemForFunction - Free JIT memory for the specified function.
/// This is never called when the JIT is currently emitting a function.
virtual void deallocateMemForFunction(const Function *F) = 0;
};
} // end namespace llvm.
#endif

438
lib/ExecutionEngine/JIT/JITEmitter.cpp
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@ -22,7 +22,7 @@
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRelocation.h"
#include "llvm/ExecutionEngine/GenericValue.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetJITInfo.h"
#include "llvm/Target/TargetMachine.h"
@ -30,7 +30,6 @@
#include "llvm/Support/MutexGuard.h"
#include "llvm/System/Disassembler.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/System/Memory.h"
#include <algorithm>
using namespace llvm;
@ -38,395 +37,6 @@ STATISTIC(NumBytes, "Number of bytes of machine code compiled");
STATISTIC(NumRelos, "Number of relocations applied");
static JIT *TheJIT = 0;
//===----------------------------------------------------------------------===//
// JITMemoryManager code.
//
namespace {
/// MemoryRangeHeader - For a range of memory, this is the header that we put
/// on the block of memory. It is carefully crafted to be one word of memory.
/// Allocated blocks have just this header, free'd blocks have FreeRangeHeader
/// which starts with this.
struct FreeRangeHeader;
struct MemoryRangeHeader {
/// ThisAllocated - This is true if this block is currently allocated. If
/// not, this can be converted to a FreeRangeHeader.
unsigned ThisAllocated : 1;
/// PrevAllocated - Keep track of whether the block immediately before us is
/// allocated. If not, the word immediately before this header is the size
/// of the previous block.
unsigned PrevAllocated : 1;
/// BlockSize - This is the size in bytes of this memory block,
/// including this header.
uintptr_t BlockSize : (sizeof(intptr_t)*8 - 2);
/// getBlockAfter - Return the memory block immediately after this one.
///
MemoryRangeHeader &getBlockAfter() const {
return *(MemoryRangeHeader*)((char*)this+BlockSize);
}
/// getFreeBlockBefore - If the block before this one is free, return it,
/// otherwise return null.
FreeRangeHeader *getFreeBlockBefore() const {
if (PrevAllocated) return 0;
intptr_t PrevSize = ((intptr_t *)this)[-1];
return (FreeRangeHeader*)((char*)this-PrevSize);
}
/// FreeBlock - Turn an allocated block into a free block, adjusting
/// bits in the object headers, and adding an end of region memory block.
FreeRangeHeader *FreeBlock(FreeRangeHeader *FreeList);
/// TrimAllocationToSize - If this allocated block is significantly larger
/// than NewSize, split it into two pieces (where the former is NewSize
/// bytes, including the header), and add the new block to the free list.
FreeRangeHeader *TrimAllocationToSize(FreeRangeHeader *FreeList,
uint64_t NewSize);
};
/// FreeRangeHeader - For a memory block that isn't already allocated, this
/// keeps track of the current block and has a pointer to the next free block.
/// Free blocks are kept on a circularly linked list.
struct FreeRangeHeader : public MemoryRangeHeader {
FreeRangeHeader *Prev;
FreeRangeHeader *Next;
/// getMinBlockSize - Get the minimum size for a memory block. Blocks
/// smaller than this size cannot be created.
static unsigned getMinBlockSize() {
return sizeof(FreeRangeHeader)+sizeof(intptr_t);
}
/// SetEndOfBlockSizeMarker - The word at the end of every free block is
/// known to be the size of the free block. Set it for this block.
void SetEndOfBlockSizeMarker() {
void *EndOfBlock = (char*)this + BlockSize;
((intptr_t *)EndOfBlock)[-1] = BlockSize;
}
FreeRangeHeader *RemoveFromFreeList() {
assert(Next->Prev == this && Prev->Next == this && "Freelist broken!");
Next->Prev = Prev;
return Prev->Next = Next;
}
void AddToFreeList(FreeRangeHeader *FreeList) {
Next = FreeList;
Prev = FreeList->Prev;
Prev->Next = this;
Next->Prev = this;
}
/// GrowBlock - The block after this block just got deallocated. Merge it
/// into the current block.
void GrowBlock(uintptr_t NewSize);
/// AllocateBlock - Mark this entire block allocated, updating freelists
/// etc. This returns a pointer to the circular free-list.
FreeRangeHeader *AllocateBlock();
};
}
/// AllocateBlock - Mark this entire block allocated, updating freelists
/// etc. This returns a pointer to the circular free-list.
FreeRangeHeader *FreeRangeHeader::AllocateBlock() {
assert(!ThisAllocated && !getBlockAfter().PrevAllocated &&
"Cannot allocate an allocated block!");
// Mark this block allocated.
ThisAllocated = 1;
getBlockAfter().PrevAllocated = 1;
// Remove it from the free list.
return RemoveFromFreeList();
}
/// FreeBlock - Turn an allocated block into a free block, adjusting
/// bits in the object headers, and adding an end of region memory block.
/// If possible, coalesce this block with neighboring blocks. Return the
/// FreeRangeHeader to allocate from.
FreeRangeHeader *MemoryRangeHeader::FreeBlock(FreeRangeHeader *FreeList) {
MemoryRangeHeader *FollowingBlock = &getBlockAfter();
assert(ThisAllocated && "This block is already allocated!");
assert(FollowingBlock->PrevAllocated && "Flags out of sync!");
FreeRangeHeader *FreeListToReturn = FreeList;
// If the block after this one is free, merge it into this block.
if (!FollowingBlock->ThisAllocated) {
FreeRangeHeader &FollowingFreeBlock = *(FreeRangeHeader *)FollowingBlock;
// "FreeList" always needs to be a valid free block. If we're about to
// coalesce with it, update our notion of what the free list is.
if (&FollowingFreeBlock == FreeList) {
FreeList = FollowingFreeBlock.Next;
FreeListToReturn = 0;
assert(&FollowingFreeBlock != FreeList && "No tombstone block?");
}
FollowingFreeBlock.RemoveFromFreeList();
// Include the following block into this one.
BlockSize += FollowingFreeBlock.BlockSize;
FollowingBlock = &FollowingFreeBlock.getBlockAfter();
// Tell the block after the block we are coalescing that this block is
// allocated.
FollowingBlock->PrevAllocated = 1;
}
assert(FollowingBlock->ThisAllocated && "Missed coalescing?");
if (FreeRangeHeader *PrevFreeBlock = getFreeBlockBefore()) {
PrevFreeBlock->GrowBlock(PrevFreeBlock->BlockSize + BlockSize);
return FreeListToReturn ? FreeListToReturn : PrevFreeBlock;
}
// Otherwise, mark this block free.
FreeRangeHeader &FreeBlock = *(FreeRangeHeader*)this;
FollowingBlock->PrevAllocated = 0;
FreeBlock.ThisAllocated = 0;
// Link this into the linked list of free blocks.
FreeBlock.AddToFreeList(FreeList);
// Add a marker at the end of the block, indicating the size of this free
// block.
FreeBlock.SetEndOfBlockSizeMarker();
return FreeListToReturn ? FreeListToReturn : &FreeBlock;
}
/// GrowBlock - The block after this block just got deallocated. Merge it
/// into the current block.
void FreeRangeHeader::GrowBlock(uintptr_t NewSize) {
assert(NewSize > BlockSize && "Not growing block?");
BlockSize = NewSize;
SetEndOfBlockSizeMarker();
getBlockAfter().PrevAllocated = 0;
}
/// TrimAllocationToSize - If this allocated block is significantly larger
/// than NewSize, split it into two pieces (where the former is NewSize
/// bytes, including the header), and add the new block to the free list.
FreeRangeHeader *MemoryRangeHeader::
TrimAllocationToSize(FreeRangeHeader *FreeList, uint64_t NewSize) {
assert(ThisAllocated && getBlockAfter().PrevAllocated &&
"Cannot deallocate part of an allocated block!");
// Round up size for alignment of header.
unsigned HeaderAlign = __alignof(FreeRangeHeader);
NewSize = (NewSize+ (HeaderAlign-1)) & ~(HeaderAlign-1);
// Size is now the size of the block we will remove from the start of the
// current block.
assert(NewSize <= BlockSize &&
"Allocating more space from this block than exists!");
// If splitting this block will cause the remainder to be too small, do not
// split the block.
if (BlockSize <= NewSize+FreeRangeHeader::getMinBlockSize())
return FreeList;
// Otherwise, we splice the required number of bytes out of this block, form
// a new block immediately after it, then mark this block allocated.
MemoryRangeHeader &FormerNextBlock = getBlockAfter();
// Change the size of this block.
BlockSize = NewSize;
// Get the new block we just sliced out and turn it into a free block.
FreeRangeHeader &NewNextBlock = (FreeRangeHeader &)getBlockAfter();
NewNextBlock.BlockSize = (char*)&FormerNextBlock - (char*)&NewNextBlock;
NewNextBlock.ThisAllocated = 0;
NewNextBlock.PrevAllocated = 1;
NewNextBlock.SetEndOfBlockSizeMarker();
FormerNextBlock.PrevAllocated = 0;
NewNextBlock.AddToFreeList(FreeList);
return &NewNextBlock;
}
namespace {
/// JITMemoryManager - Manage memory for the JIT code generation in a logical,
/// sane way. This splits a large block of MAP_NORESERVE'd memory into two
/// sections, one for function stubs, one for the functions themselves. We
/// have to do this because we may need to emit a function stub while in the
/// middle of emitting a function, and we don't know how large the function we
/// are emitting is. This never bothers to release the memory, because when
/// we are ready to destroy the JIT, the program exits.
class JITMemoryManager {
std::vector<sys::MemoryBlock> Blocks; // Memory blocks allocated by the JIT
FreeRangeHeader *FreeMemoryList; // Circular list of free blocks.
// When emitting code into a memory block, this is the block.
MemoryRangeHeader *CurBlock;
unsigned char *CurStubPtr, *StubBase;
unsigned char *GOTBase; // Target Specific reserved memory
// Centralize memory block allocation.
sys::MemoryBlock getNewMemoryBlock(unsigned size);
std::map<const Function*, MemoryRangeHeader*> FunctionBlocks;
public:
JITMemoryManager(bool useGOT);
~JITMemoryManager();
inline unsigned char *allocateStub(unsigned StubSize, unsigned Alignment);
/// startFunctionBody - When a function starts, allocate a block of free
/// executable memory, returning a pointer to it and its actual size.
unsigned char *startFunctionBody(uintptr_t &ActualSize) {
CurBlock = FreeMemoryList;
// Allocate the entire memory block.
FreeMemoryList = FreeMemoryList->AllocateBlock();
ActualSize = CurBlock->BlockSize-sizeof(MemoryRangeHeader);
return (unsigned char *)(CurBlock+1);
}
/// endFunctionBody - The function F is now allocated, and takes the memory
/// in the range [FunctionStart,FunctionEnd).
void endFunctionBody(const Function *F, unsigned char *FunctionStart,
unsigned char *FunctionEnd) {
assert(FunctionEnd > FunctionStart);
assert(FunctionStart == (unsigned char *)(CurBlock+1) &&
"Mismatched function start/end!");
uintptr_t BlockSize = FunctionEnd - (unsigned char *)CurBlock;
FunctionBlocks[F] = CurBlock;
// Release the memory at the end of this block that isn't needed.
FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
}
unsigned char *getGOTBase() const {
return GOTBase;
}
bool isManagingGOT() const {
return GOTBase != NULL;
}
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body.
void deallocateMemForFunction(const Function *F) {
std::map<const Function*, MemoryRangeHeader*>::iterator
I = FunctionBlocks.find(F);
if (I == FunctionBlocks.end()) return;
// Find the block that is allocated for this function.
MemoryRangeHeader *MemRange = I->second;
assert(MemRange->ThisAllocated && "Block isn't allocated!");
// Fill the buffer with garbage!
DEBUG(memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange)));
// Free the memory.
FreeMemoryList = MemRange->FreeBlock(FreeMemoryList);
// Finally, remove this entry from FunctionBlocks.
FunctionBlocks.erase(I);
}
};
}
JITMemoryManager::JITMemoryManager(bool useGOT) {
// Allocate a 16M block of memory for functions.
sys::MemoryBlock MemBlock = getNewMemoryBlock(16 << 20);
unsigned char *MemBase = reinterpret_cast<unsigned char*>(MemBlock.base());
// Allocate stubs backwards from the base, allocate functions forward
// from the base.
StubBase = MemBase;
CurStubPtr = MemBase + 512*1024; // Use 512k for stubs, working backwards.
// 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 = 0;
/// 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 = (char*)Mem2 - (char*)Mem1;
// 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*)CurStubPtr;
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;
// Allocate the GOT.
GOTBase = NULL;
if (useGOT) GOTBase = new unsigned char[sizeof(void*) * 8192];
}
JITMemoryManager::~JITMemoryManager() {
for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
sys::Memory::ReleaseRWX(Blocks[i]);
delete[] GOTBase;
Blocks.clear();
}
unsigned char *JITMemoryManager::allocateStub(unsigned StubSize,
unsigned Alignment) {
CurStubPtr -= StubSize;
CurStubPtr = (unsigned char*)(((intptr_t)CurStubPtr) &
~(intptr_t)(Alignment-1));
if (CurStubPtr < StubBase) {
// FIXME: allocate a new block
cerr << "JIT ran out of memory for function stubs!\n";
abort();
}
return CurStubPtr;
}
sys::MemoryBlock JITMemoryManager::getNewMemoryBlock(unsigned size) {
// Allocate a new block close to the last one.
const sys::MemoryBlock *BOld = Blocks.empty() ? 0 : &Blocks.front();
std::string ErrMsg;
sys::MemoryBlock B = sys::Memory::AllocateRWX(size, BOld, &ErrMsg);
if (B.base() == 0) {
cerr << "Allocation failed when allocating new memory in the JIT\n";
cerr << ErrMsg << "\n";
abort();
}
Blocks.push_back(B);
return B;
}
//===----------------------------------------------------------------------===//
// JIT lazy compilation code.
@ -504,9 +114,9 @@ namespace {
}
/// getGOTIndexForAddress - Return a new or existing index in the GOT for
/// and address. This function only manages slots, it does not manage the
/// an address. This function only manages slots, it does not manage the
/// contents of the slots or the memory associated with the GOT.
unsigned getGOTIndexForAddr(void* addr);
unsigned getGOTIndexForAddr(void *addr);
/// JITCompilerFn - This function is called to resolve a stub to a compiled
/// address. If the LLVM Function corresponding to the stub has not yet
@ -597,7 +207,6 @@ unsigned JITResolver::getGOTIndexForAddr(void* addr) {
revGOTMap[addr] = idx;
DOUT << "Adding GOT entry " << idx
<< " for addr " << addr << "\n";
// ((void**)MemMgr.getGOTBase())[idx] = addr;
}
return idx;
}
@ -669,7 +278,7 @@ namespace {
/// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
/// used to output functions to memory for execution.
class JITEmitter : public MachineCodeEmitter {
JITMemoryManager MemMgr;
JITMemoryManager *MemMgr;
// When outputting a function stub in the context of some other function, we
// save BufferBegin/BufferEnd/CurBufferPtr here.
@ -703,9 +312,15 @@ namespace {
/// Resolver - This contains info about the currently resolved functions.
JITResolver Resolver;
public:
JITEmitter(JIT &jit)
: MemMgr(jit.getJITInfo().needsGOT()), Resolver(jit) {
if (MemMgr.isManagingGOT()) DOUT << "JIT is managing a GOT\n";
JITEmitter(JIT &jit) : Resolver(jit) {
MemMgr = JITMemoryManager::CreateDefaultMemManager();
if (jit.getJITInfo().needsGOT()) {
MemMgr->AllocateGOT();
DOUT << "JIT is managing a GOT\n";
}
}
~JITEmitter() {
delete MemMgr;
}
JITResolver &getJITResolver() { return Resolver; }
@ -742,7 +357,7 @@ namespace {
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body.
void deallocateMemForFunction(Function *F) {
MemMgr.deallocateMemForFunction(F);
MemMgr->deallocateMemForFunction(F);
}
private:
void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
@ -783,7 +398,8 @@ void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
void JITEmitter::startFunction(MachineFunction &F) {
uintptr_t ActualSize;
BufferBegin = CurBufferPtr = MemMgr.startFunctionBody(ActualSize);
BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
ActualSize);
BufferEnd = BufferBegin+ActualSize;
// Ensure the constant pool/jump table info is at least 4-byte aligned.
@ -814,7 +430,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
(unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
unsigned char *FnEnd = CurBufferPtr;
MemMgr.endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
NumBytes += FnEnd-FnStart;
if (!Relocations.empty()) {
@ -847,29 +463,29 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
// if we are managing the GOT and the relocation wants an index,
// give it one
if (MemMgr.isManagingGOT() && MR.isGOTRelative()) {
if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
MR.setGOTIndex(idx);
if (((void**)MemMgr.getGOTBase())[idx] != ResultPtr) {
if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
DOUT << "GOT was out of date for " << ResultPtr
<< " pointing at " << ((void**)MemMgr.getGOTBase())[idx]
<< " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
<< "\n";
((void**)MemMgr.getGOTBase())[idx] = ResultPtr;
((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
}
}
}
TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
Relocations.size(), MemMgr.getGOTBase());
Relocations.size(), MemMgr->getGOTBase());
}
// Update the GOT entry for F to point to the new code.
if (MemMgr.isManagingGOT()) {
if (MemMgr->isManagingGOT()) {
unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
if (((void**)MemMgr.getGOTBase())[idx] != (void*)BufferBegin) {
if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
DOUT << "GOT was out of date for " << (void*)BufferBegin
<< " pointing at " << ((void**)MemMgr.getGOTBase())[idx] << "\n";
((void**)MemMgr.getGOTBase())[idx] = (void*)BufferBegin;
<< " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
}
}
@ -976,7 +592,7 @@ void JITEmitter::startFunctionStub(unsigned StubSize, unsigned Alignment) {
SavedBufferEnd = BufferEnd;
SavedCurBufferPtr = CurBufferPtr;
BufferBegin = CurBufferPtr = MemMgr.allocateStub(StubSize, Alignment);
BufferBegin = CurBufferPtr = MemMgr->allocateStub(StubSize, Alignment);
BufferEnd = BufferBegin+StubSize+1;
}

427
lib/ExecutionEngine/JIT/JITMemoryManager.cpp Normal file
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@ -0,0 +1,427 @@
//===-- JITMemoryManager.cpp - Memory Allocator for JIT'd code ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the DefaultJITMemoryManager class.
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/Support/Compiler.h"
#include "llvm/System/Memory.h"
#include <map>
#include <vector>
using namespace llvm;
JITMemoryManager::~JITMemoryManager() {}
//===----------------------------------------------------------------------===//
// Memory Block Implementation.
//===----------------------------------------------------------------------===//
namespace {
/// MemoryRangeHeader - For a range of memory, this is the header that we put
/// on the block of memory. It is carefully crafted to be one word of memory.
/// Allocated blocks have just this header, free'd blocks have FreeRangeHeader
/// which starts with this.
struct FreeRangeHeader;
struct MemoryRangeHeader {
/// ThisAllocated - This is true if this block is currently allocated. If
/// not, this can be converted to a FreeRangeHeader.
unsigned ThisAllocated : 1;
/// PrevAllocated - Keep track of whether the block immediately before us is
/// allocated. If not, the word immediately before this header is the size
/// of the previous block.
unsigned PrevAllocated : 1;
/// BlockSize - This is the size in bytes of this memory block,
/// including this header.
uintptr_t BlockSize : (sizeof(intptr_t)*8 - 2);
/// getBlockAfter - Return the memory block immediately after this one.
///
MemoryRangeHeader &getBlockAfter() const {
return *(MemoryRangeHeader*)((char*)this+BlockSize);
}
/// getFreeBlockBefore - If the block before this one is free, return it,
/// otherwise return null.
FreeRangeHeader *getFreeBlockBefore() const {
if (PrevAllocated) return 0;
intptr_t PrevSize = ((intptr_t *)this)[-1];
return (FreeRangeHeader*)((char*)this-PrevSize);
}
/// FreeBlock - Turn an allocated block into a free block, adjusting
/// bits in the object headers, and adding an end of region memory block.
FreeRangeHeader *FreeBlock(FreeRangeHeader *FreeList);
/// TrimAllocationToSize - If this allocated block is significantly larger
/// than NewSize, split it into two pieces (where the former is NewSize
/// bytes, including the header), and add the new block to the free list.
FreeRangeHeader *TrimAllocationToSize(FreeRangeHeader *FreeList,
uint64_t NewSize);
};
/// FreeRangeHeader - For a memory block that isn't already allocated, this
/// keeps track of the current block and has a pointer to the next free block.
/// Free blocks are kept on a circularly linked list.
struct FreeRangeHeader : public MemoryRangeHeader {
FreeRangeHeader *Prev;
FreeRangeHeader *Next;
/// getMinBlockSize - Get the minimum size for a memory block. Blocks
/// smaller than this size cannot be created.
static unsigned getMinBlockSize() {
return sizeof(FreeRangeHeader)+sizeof(intptr_t);
}
/// SetEndOfBlockSizeMarker - The word at the end of every free block is
/// known to be the size of the free block. Set it for this block.
void SetEndOfBlockSizeMarker() {
void *EndOfBlock = (char*)this + BlockSize;
((intptr_t *)EndOfBlock)[-1] = BlockSize;
}
FreeRangeHeader *RemoveFromFreeList() {
assert(Next->Prev == this && Prev->Next == this && "Freelist broken!");
Next->Prev = Prev;
return Prev->Next = Next;
}
void AddToFreeList(FreeRangeHeader *FreeList) {
Next = FreeList;
Prev = FreeList->Prev;
Prev->Next = this;
Next->Prev = this;
}
/// GrowBlock - The block after this block just got deallocated. Merge it
/// into the current block.
void GrowBlock(uintptr_t NewSize);
/// AllocateBlock - Mark this entire block allocated, updating freelists
/// etc. This returns a pointer to the circular free-list.
FreeRangeHeader *AllocateBlock();
};
}
/// AllocateBlock - Mark this entire block allocated, updating freelists
/// etc. This returns a pointer to the circular free-list.
FreeRangeHeader *FreeRangeHeader::AllocateBlock() {
assert(!ThisAllocated && !getBlockAfter().PrevAllocated &&
"Cannot allocate an allocated block!");
// Mark this block allocated.
ThisAllocated = 1;
getBlockAfter().PrevAllocated = 1;
// Remove it from the free list.
return RemoveFromFreeList();
}
/// FreeBlock - Turn an allocated block into a free block, adjusting
/// bits in the object headers, and adding an end of region memory block.
/// If possible, coalesce this block with neighboring blocks. Return the
/// FreeRangeHeader to allocate from.
FreeRangeHeader *MemoryRangeHeader::FreeBlock(FreeRangeHeader *FreeList) {
MemoryRangeHeader *FollowingBlock = &getBlockAfter();
assert(ThisAllocated && "This block is already allocated!");
assert(FollowingBlock->PrevAllocated && "Flags out of sync!");
FreeRangeHeader *FreeListToReturn = FreeList;
// If the block after this one is free, merge it into this block.
if (!FollowingBlock->ThisAllocated) {
FreeRangeHeader &FollowingFreeBlock = *(FreeRangeHeader *)FollowingBlock;
// "FreeList" always needs to be a valid free block. If we're about to
// coalesce with it, update our notion of what the free list is.
if (&FollowingFreeBlock == FreeList) {
FreeList = FollowingFreeBlock.Next;
FreeListToReturn = 0;
assert(&FollowingFreeBlock != FreeList && "No tombstone block?");
}
FollowingFreeBlock.RemoveFromFreeList();
// Include the following block into this one.
BlockSize += FollowingFreeBlock.BlockSize;
FollowingBlock = &FollowingFreeBlock.getBlockAfter();
// Tell the block after the block we are coalescing that this block is
// allocated.
FollowingBlock->PrevAllocated = 1;
}
assert(FollowingBlock->ThisAllocated && "Missed coalescing?");
if (FreeRangeHeader *PrevFreeBlock = getFreeBlockBefore()) {
PrevFreeBlock->GrowBlock(PrevFreeBlock->BlockSize + BlockSize);
return FreeListToReturn ? FreeListToReturn : PrevFreeBlock;
}
// Otherwise, mark this block free.
FreeRangeHeader &FreeBlock = *(FreeRangeHeader*)this;
FollowingBlock->PrevAllocated = 0;
FreeBlock.ThisAllocated = 0;
// Link this into the linked list of free blocks.
FreeBlock.AddToFreeList(FreeList);
// Add a marker at the end of the block, indicating the size of this free
// block.
FreeBlock.SetEndOfBlockSizeMarker();
return FreeListToReturn ? FreeListToReturn : &FreeBlock;
}
/// GrowBlock - The block after this block just got deallocated. Merge it
/// into the current block.
void FreeRangeHeader::GrowBlock(uintptr_t NewSize) {
assert(NewSize > BlockSize && "Not growing block?");
BlockSize = NewSize;
SetEndOfBlockSizeMarker();
getBlockAfter().PrevAllocated = 0;
}
/// TrimAllocationToSize - If this allocated block is significantly larger
/// than NewSize, split it into two pieces (where the former is NewSize
/// bytes, including the header), and add the new block to the free list.
FreeRangeHeader *MemoryRangeHeader::
TrimAllocationToSize(FreeRangeHeader *FreeList, uint64_t NewSize) {
assert(ThisAllocated && getBlockAfter().PrevAllocated &&
"Cannot deallocate part of an allocated block!");
// Round up size for alignment of header.
unsigned HeaderAlign = __alignof(FreeRangeHeader);
NewSize = (NewSize+ (HeaderAlign-1)) & ~(HeaderAlign-1);
// Size is now the size of the block we will remove from the start of the
// current block.
assert(NewSize <= BlockSize &&
"Allocating more space from this block than exists!");
// If splitting this block will cause the remainder to be too small, do not
// split the block.
if (BlockSize <= NewSize+FreeRangeHeader::getMinBlockSize())
return FreeList;
// Otherwise, we splice the required number of bytes out of this block, form
// a new block immediately after it, then mark this block allocated.
MemoryRangeHeader &FormerNextBlock = getBlockAfter();
// Change the size of this block.
BlockSize = NewSize;
// Get the new block we just sliced out and turn it into a free block.
FreeRangeHeader &NewNextBlock = (FreeRangeHeader &)getBlockAfter();
NewNextBlock.BlockSize = (char*)&FormerNextBlock - (char*)&NewNextBlock;
NewNextBlock.ThisAllocated = 0;
NewNextBlock.PrevAllocated = 1;
NewNextBlock.SetEndOfBlockSizeMarker();
FormerNextBlock.PrevAllocated = 0;
NewNextBlock.AddToFreeList(FreeList);
return &NewNextBlock;
}
//===----------------------------------------------------------------------===//
// Memory Block Implementation.
//===----------------------------------------------------------------------===//
namespace {
/// DefaultJITMemoryManager - Manage memory for the JIT code generation.
/// This splits a large block of MAP_NORESERVE'd memory into two
/// sections, one for function stubs, one for the functions themselves. We
/// have to do this because we may need to emit a function stub while in the
/// middle of emitting a function, and we don't know how large the function we
/// are emitting is.
class VISIBILITY_HIDDEN DefaultJITMemoryManager : public JITMemoryManager {
std::vector<sys::MemoryBlock> Blocks; // Memory blocks allocated by the JIT
FreeRangeHeader *FreeMemoryList; // Circular list of free blocks.
// When emitting code into a memory block, this is the block.
MemoryRangeHeader *CurBlock;
unsigned char *CurStubPtr, *StubBase;
unsigned char *GOTBase; // Target Specific reserved memory
// Centralize memory block allocation.
sys::MemoryBlock getNewMemoryBlock(unsigned size);
std::map<const Function*, MemoryRangeHeader*> FunctionBlocks;
public:
DefaultJITMemoryManager();
~DefaultJITMemoryManager();
void AllocateGOT();
unsigned char *allocateStub(unsigned StubSize, unsigned Alignment);
/// startFunctionBody - When a function starts, allocate a block of free
/// executable memory, returning a pointer to it and its actual size.
unsigned char *startFunctionBody(const Function *F, uintptr_t &ActualSize) {
CurBlock = FreeMemoryList;
// Allocate the entire memory block.
FreeMemoryList = FreeMemoryList->AllocateBlock();
ActualSize = CurBlock->BlockSize-sizeof(MemoryRangeHeader);
return (unsigned char *)(CurBlock+1);
}
/// endFunctionBody - The function F is now allocated, and takes the memory
/// in the range [FunctionStart,FunctionEnd).
void endFunctionBody(const Function *F, unsigned char *FunctionStart,
unsigned char *FunctionEnd) {
assert(FunctionEnd > FunctionStart);
assert(FunctionStart == (unsigned char *)(CurBlock+1) &&
"Mismatched function start/end!");
uintptr_t BlockSize = FunctionEnd - (unsigned char *)CurBlock;
FunctionBlocks[F] = CurBlock;
// Release the memory at the end of this block that isn't needed.
FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
}
unsigned char *getGOTBase() const {
return GOTBase;
}
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body.
void deallocateMemForFunction(const Function *F) {
std::map<const Function*, MemoryRangeHeader*>::iterator
I = FunctionBlocks.find(F);
if (I == FunctionBlocks.end()) return;
// Find the block that is allocated for this function.
MemoryRangeHeader *MemRange = I->second;
assert(MemRange->ThisAllocated && "Block isn't allocated!");
// Fill the buffer with garbage!
#ifndef NDEBUG
memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange));
#endif
// Free the memory.
FreeMemoryList = MemRange->FreeBlock(FreeMemoryList);
// Finally, remove this entry from FunctionBlocks.
FunctionBlocks.erase(I);
}
};
}
DefaultJITMemoryManager::DefaultJITMemoryManager() {
// Allocate a 16M block of memory for functions.
sys::MemoryBlock MemBlock = getNewMemoryBlock(16 << 20);
unsigned char *MemBase = reinterpret_cast<unsigned char*>(MemBlock.base());
// Allocate stubs backwards from the base, allocate functions forward
// from the base.
StubBase = MemBase;
CurStubPtr = MemBase + 512*1024; // Use 512k for stubs, working backwards.
// 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 = 0;
/// 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 = (char*)Mem2 - (char*)Mem1;
// 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*)CurStubPtr;
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 unsigned char[sizeof(void*) * 8192];
HasGOT = true;
}
DefaultJITMemoryManager::~DefaultJITMemoryManager() {
for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
sys::Memory::ReleaseRWX(Blocks[i]);
delete[] GOTBase;
Blocks.clear();
}
unsigned char *DefaultJITMemoryManager::allocateStub(unsigned StubSize,
unsigned Alignment) {
CurStubPtr -= StubSize;
CurStubPtr = (unsigned char*)(((intptr_t)CurStubPtr) &
~(intptr_t)(Alignment-1));
if (CurStubPtr < StubBase) {
// FIXME: allocate a new block
fprintf(stderr, "JIT ran out of memory for function stubs!\n");
abort();
}
return CurStubPtr;
}
sys::MemoryBlock DefaultJITMemoryManager::getNewMemoryBlock(unsigned size) {
// Allocate a new block close to the last one.
const sys::MemoryBlock *BOld = Blocks.empty() ? 0 : &Blocks.front();
std::string ErrMsg;
sys::MemoryBlock B = sys::Memory::AllocateRWX(size, BOld, &ErrMsg);
if (B.base() == 0) {
fprintf(stderr,
"Allocation failed when allocating new memory in the JIT\n%s\n",
ErrMsg.c_str());
abort();
}
Blocks.push_back(B);
return B;
}
JITMemoryManager *JITMemoryManager::CreateDefaultMemManager() {
return new DefaultJITMemoryManager();
}