//
// 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 is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "jit"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/GlobalValue.h"
+#include "llvm/Support/Allocator.h"
#include "llvm/Support/Compiler.h"
-#include "llvm/System/Memory.h"
-#include <map>
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Memory.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Config/config.h"
#include <vector>
+#include <cassert>
+#include <climits>
+#include <cstring>
+
+#if defined(__linux__)
+#if defined(HAVE_SYS_STAT_H)
+#include <sys/stat.h>
+#endif
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+
using namespace llvm;
+STATISTIC(NumSlabs, "Number of slabs of memory allocated by the JIT");
JITMemoryManager::~JITMemoryManager() {}
/// 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);
-
+ uintptr_t BlockSize : (sizeof(intptr_t)*CHAR_BIT - 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 {
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,
+ FreeRangeHeader *TrimAllocationToSize(FreeRangeHeader *FreeList,
uint64_t NewSize);
};
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() {
Next->Prev = Prev;
return Prev->Next = Next;
}
-
+
void AddToFreeList(FreeRangeHeader *FreeList) {
Next = FreeList;
Prev = FreeList->Prev;
/// 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();
// Mark this block allocated.
ThisAllocated = 1;
getBlockAfter().PrevAllocated = 1;
-
+
// Remove it from the free list.
return RemoveFromFreeList();
}
/// FreeRangeHeader to allocate from.
FreeRangeHeader *MemoryRangeHeader::FreeBlock(FreeRangeHeader *FreeList) {
MemoryRangeHeader *FollowingBlock = &getBlockAfter();
- assert(ThisAllocated && "This block is already allocated!");
+ assert(ThisAllocated && "This block is already free!");
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;
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;
assert(ThisAllocated && getBlockAfter().PrevAllocated &&
"Cannot deallocate part of an allocated block!");
+ // Don't allow blocks to be trimmed below minimum required size
+ NewSize = std::max<uint64_t>(FreeRangeHeader::getMinBlockSize(), NewSize);
+
// 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;
// Memory Block Implementation.
//===----------------------------------------------------------------------===//
-namespace {
+namespace {
+
+ class DefaultJITMemoryManager;
+
+ class JITSlabAllocator : public SlabAllocator {
+ DefaultJITMemoryManager &JMM;
+ public:
+ JITSlabAllocator(DefaultJITMemoryManager &jmm) : JMM(jmm) { }
+ virtual ~JITSlabAllocator() { }
+ virtual MemSlab *Allocate(size_t Size);
+ virtual void Deallocate(MemSlab *Slab);
+ };
+
/// 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.
-
+ class DefaultJITMemoryManager : public JITMemoryManager {
+
+ // Whether to poison freed memory.
+ bool PoisonMemory;
+
+ /// LastSlab - This points to the last slab allocated and is used as the
+ /// NearBlock parameter to AllocateRWX so that we can attempt to lay out all
+ /// stubs, data, and code contiguously in memory. In general, however, this
+ /// is not possible because the NearBlock parameter is ignored on Windows
+ /// platforms and even on Unix it works on a best-effort pasis.
+ sys::MemoryBlock LastSlab;
+
+ // Memory slabs allocated by the JIT. We refer to them as slabs so we don't
+ // confuse them with the blocks of memory described above.
+ std::vector<sys::MemoryBlock> CodeSlabs;
+ JITSlabAllocator BumpSlabAllocator;
+ BumpPtrAllocator StubAllocator;
+ BumpPtrAllocator DataAllocator;
+
+ // Circular list of free blocks.
+ FreeRangeHeader *FreeMemoryList;
+
// 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;
+
+ uint8_t *GOTBase; // Target Specific reserved memory
public:
DefaultJITMemoryManager();
~DefaultJITMemoryManager();
+ /// allocateNewSlab - Allocates a new MemoryBlock and remembers it as the
+ /// last slab it allocated, so that subsequent allocations follow it.
+ sys::MemoryBlock allocateNewSlab(size_t size);
+
+ /// DefaultCodeSlabSize - When we have to go map more memory, we allocate at
+ /// least this much unless more is requested.
+ static const size_t DefaultCodeSlabSize;
+
+ /// DefaultSlabSize - Allocate data into slabs of this size unless we get
+ /// an allocation above SizeThreshold.
+ static const size_t DefaultSlabSize;
+
+ /// DefaultSizeThreshold - For any allocation larger than this threshold, we
+ /// should allocate a separate slab.
+ static const size_t DefaultSizeThreshold;
+
+ /// getPointerToNamedFunction - This method returns the address of the
+ /// specified function by using the dlsym function call.
+ virtual void *getPointerToNamedFunction(const std::string &Name,
+ bool AbortOnFailure = true);
+
void AllocateGOT();
- unsigned char *allocateStub(unsigned StubSize, unsigned Alignment);
-
+ // Testing methods.
+ virtual bool CheckInvariants(std::string &ErrorStr);
+ size_t GetDefaultCodeSlabSize() { return DefaultCodeSlabSize; }
+ size_t GetDefaultDataSlabSize() { return DefaultSlabSize; }
+ size_t GetDefaultStubSlabSize() { return DefaultSlabSize; }
+ unsigned GetNumCodeSlabs() { return CodeSlabs.size(); }
+ unsigned GetNumDataSlabs() { return DataAllocator.GetNumSlabs(); }
+ unsigned GetNumStubSlabs() { return StubAllocator.GetNumSlabs(); }
+
/// 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;
-
+ uint8_t *startFunctionBody(const Function *F, uintptr_t &ActualSize) {
+
+ FreeRangeHeader* candidateBlock = FreeMemoryList;
+ FreeRangeHeader* head = FreeMemoryList;
+ FreeRangeHeader* iter = head->Next;
+
+ uintptr_t largest = candidateBlock->BlockSize;
+
+ // Search for the largest free block
+ while (iter != head) {
+ if (iter->BlockSize > largest) {
+ largest = iter->BlockSize;
+ candidateBlock = iter;
+ }
+ iter = iter->Next;
+ }
+
+ largest = largest - sizeof(MemoryRangeHeader);
+
+ // If this block isn't big enough for the allocation desired, allocate
+ // another block of memory and add it to the free list.
+ if (largest < ActualSize ||
+ largest <= FreeRangeHeader::getMinBlockSize()) {
+ DEBUG(dbgs() << "JIT: Allocating another slab of memory for function.");
+ candidateBlock = allocateNewCodeSlab((size_t)ActualSize);
+ }
+
+ // Select this candidate block for allocation
+ CurBlock = candidateBlock;
+
// Allocate the entire memory block.
- FreeMemoryList = FreeMemoryList->AllocateBlock();
- ActualSize = CurBlock->BlockSize-sizeof(MemoryRangeHeader);
- return (unsigned char *)(CurBlock+1);
+ FreeMemoryList = candidateBlock->AllocateBlock();
+ ActualSize = CurBlock->BlockSize - sizeof(MemoryRangeHeader);
+ return (uint8_t *)(CurBlock + 1);
+ }
+
+ /// allocateNewCodeSlab - Helper method to allocate a new slab of code
+ /// memory from the OS and add it to the free list. Returns the new
+ /// FreeRangeHeader at the base of the slab.
+ FreeRangeHeader *allocateNewCodeSlab(size_t MinSize) {
+ // If the user needs at least MinSize free memory, then we account for
+ // two MemoryRangeHeaders: the one in the user's block, and the one at the
+ // end of the slab.
+ size_t PaddedMin = MinSize + 2 * sizeof(MemoryRangeHeader);
+ size_t SlabSize = std::max(DefaultCodeSlabSize, PaddedMin);
+ sys::MemoryBlock B = allocateNewSlab(SlabSize);
+ CodeSlabs.push_back(B);
+ char *MemBase = (char*)(B.base());
+
+ // Put a tiny allocated block at the end of the memory chunk, so when
+ // FreeBlock calls getBlockAfter it doesn't fall off the end.
+ MemoryRangeHeader *EndBlock =
+ (MemoryRangeHeader*)(MemBase + B.size()) - 1;
+ EndBlock->ThisAllocated = 1;
+ EndBlock->PrevAllocated = 0;
+ EndBlock->BlockSize = sizeof(MemoryRangeHeader);
+
+ // Start out with a vast new block of free memory.
+ FreeRangeHeader *NewBlock = (FreeRangeHeader*)MemBase;
+ NewBlock->ThisAllocated = 0;
+ // Make sure getFreeBlockBefore doesn't look into unmapped memory.
+ NewBlock->PrevAllocated = 1;
+ NewBlock->BlockSize = (uintptr_t)EndBlock - (uintptr_t)NewBlock;
+ NewBlock->SetEndOfBlockSizeMarker();
+ NewBlock->AddToFreeList(FreeMemoryList);
+
+ assert(NewBlock->BlockSize - sizeof(MemoryRangeHeader) >= MinSize &&
+ "The block was too small!");
+ return NewBlock;
}
-
+
/// 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) {
+ void endFunctionBody(const Function *F, uint8_t *FunctionStart,
+ uint8_t *FunctionEnd) {
assert(FunctionEnd > FunctionStart);
- assert(FunctionStart == (unsigned char *)(CurBlock+1) &&
+ assert(FunctionStart == (uint8_t *)(CurBlock+1) &&
"Mismatched function start/end!");
-
- uintptr_t BlockSize = FunctionEnd - (unsigned char *)CurBlock;
- FunctionBlocks[F] = CurBlock;
+
+ uintptr_t BlockSize = FunctionEnd - (uint8_t *)CurBlock;
+
+ // Release the memory at the end of this block that isn't needed.
+ FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
+ }
+
+ /// allocateSpace - Allocate a memory block of the given size. This method
+ /// cannot be called between calls to startFunctionBody and endFunctionBody.
+ uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) {
+ CurBlock = FreeMemoryList;
+ FreeMemoryList = FreeMemoryList->AllocateBlock();
+
+ uint8_t *result = (uint8_t *)(CurBlock + 1);
+
+ if (Alignment == 0) Alignment = 1;
+ result = (uint8_t*)(((intptr_t)result+Alignment-1) &
+ ~(intptr_t)(Alignment-1));
+
+ uintptr_t BlockSize = result + Size - (uint8_t *)CurBlock;
+ FreeMemoryList =CurBlock->TrimAllocationToSize(FreeMemoryList, BlockSize);
+
+ return result;
+ }
+
+ /// allocateStub - Allocate memory for a function stub.
+ uint8_t *allocateStub(const GlobalValue* F, unsigned StubSize,
+ unsigned Alignment) {
+ return (uint8_t*)StubAllocator.Allocate(StubSize, Alignment);
+ }
+
+ /// allocateGlobal - Allocate memory for a global.
+ uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) {
+ return (uint8_t*)DataAllocator.Allocate(Size, Alignment);
+ }
+
+ /// allocateCodeSection - Allocate memory for a code section.
+ uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
+ unsigned SectionID) {
+ // Grow the required block size to account for the block header
+ Size += sizeof(*CurBlock);
+
+ // FIXME: Alignement handling.
+ FreeRangeHeader* candidateBlock = FreeMemoryList;
+ FreeRangeHeader* head = FreeMemoryList;
+ FreeRangeHeader* iter = head->Next;
+
+ uintptr_t largest = candidateBlock->BlockSize;
+
+ // Search for the largest free block.
+ while (iter != head) {
+ if (iter->BlockSize > largest) {
+ largest = iter->BlockSize;
+ candidateBlock = iter;
+ }
+ iter = iter->Next;
+ }
+
+ largest = largest - sizeof(MemoryRangeHeader);
+
+ // If this block isn't big enough for the allocation desired, allocate
+ // another block of memory and add it to the free list.
+ if (largest < Size || largest <= FreeRangeHeader::getMinBlockSize()) {
+ DEBUG(dbgs() << "JIT: Allocating another slab of memory for function.");
+ candidateBlock = allocateNewCodeSlab((size_t)Size);
+ }
+
+ // 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, bool IsReadOnly) {
+ return (uint8_t*)DataAllocator.Allocate(Size, Alignment);
+ }
+
+ bool applyPermissions(std::string *ErrMsg) {
+ return false;
+ }
+
+ /// 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);
}
-
- unsigned char *getGOTBase() const {
+
+ uint8_t *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;
-
+
+ void deallocateBlock(void *Block) {
// Find the block that is allocated for this function.
- MemoryRangeHeader *MemRange = I->second;
+ MemoryRangeHeader *MemRange = static_cast<MemoryRangeHeader*>(Block) - 1;
assert(MemRange->ThisAllocated && "Block isn't allocated!");
-
+
// Fill the buffer with garbage!
-#ifndef NDEBUG
- memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange));
-#endif
-
+ if (PoisonMemory) {
+ memset(MemRange+1, 0xCD, MemRange->BlockSize-sizeof(*MemRange));
+ }
+
// Free the memory.
FreeMemoryList = MemRange->FreeBlock(FreeMemoryList);
-
- // Finally, remove this entry from FunctionBlocks.
- FunctionBlocks.erase(I);
+ }
+
+ /// 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;
}
};
}
-DefaultJITMemoryManager::DefaultJITMemoryManager() {
- // Allocate a 16M block of memory for functions.
- sys::MemoryBlock MemBlock = getNewMemoryBlock(16 << 20);
+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) {
- unsigned char *MemBase = reinterpret_cast<unsigned char*>(MemBlock.base());
+ // Allocate space for code.
+ sys::MemoryBlock MemBlock = allocateNewSlab(DefaultCodeSlabSize);
+ CodeSlabs.push_back(MemBlock);
+ uint8_t *MemBase = (uint8_t*)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.
// 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;
-
+ Mem3->BlockSize = sizeof(MemoryRangeHeader);
+
/// Add a tiny free region so that the free list always has one entry.
- FreeRangeHeader *Mem2 =
+ FreeRangeHeader *Mem2 =
(FreeRangeHeader *)(((char*)Mem3)-FreeRangeHeader::getMinBlockSize());
Mem2->ThisAllocated = 0;
Mem2->PrevAllocated = 1;
MemoryRangeHeader *Mem1 = (MemoryRangeHeader*)Mem2-1;
Mem1->ThisAllocated = 1;
Mem1->PrevAllocated = 0;
- Mem1->BlockSize = (char*)Mem2 - (char*)Mem1;
-
+ 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*)CurStubPtr;
+ 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;
void DefaultJITMemoryManager::AllocateGOT() {
assert(GOTBase == 0 && "Cannot allocate the got multiple times");
- GOTBase = new unsigned char[sizeof(void*) * 8192];
+ GOTBase = new uint8_t[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();
-}
+ for (unsigned i = 0, e = CodeSlabs.size(); i != e; ++i)
+ sys::Memory::ReleaseRWX(CodeSlabs[i]);
-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;
+ delete[] GOTBase;
}
-sys::MemoryBlock DefaultJITMemoryManager::getNewMemoryBlock(unsigned size) {
+sys::MemoryBlock DefaultJITMemoryManager::allocateNewSlab(size_t 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);
+ sys::MemoryBlock *LastSlabPtr = LastSlab.base() ? &LastSlab : 0;
+ sys::MemoryBlock B = sys::Memory::AllocateRWX(size, LastSlabPtr, &ErrMsg);
if (B.base() == 0) {
- fprintf(stderr,
- "Allocation failed when allocating new memory in the JIT\n%s\n",
- ErrMsg.c_str());
- abort();
+ 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());
}
- Blocks.push_back(B);
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;
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