It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
new file mode 100644
index 0000000..484af48
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -0,0 +1,1067 @@
+//===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a MachineCodeEmitter object that is used by the JIT to
+// write machine code to memory and remember where relocatable values are.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "jit"
+#include "JIT.h"
+#include "llvm/Constant.h"
+#include "llvm/Module.h"
+#include "llvm/Type.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
+#include "llvm/CodeGen/MachineRelocation.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetJITInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/Debug.h"
+#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;
+
+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.
+ intptr_t 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.
+ intptr_t 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.
+//
+namespace {
+ class JITResolverState {
+ private:
+ /// FunctionToStubMap - Keep track of the stub created for a particular
+ /// function so that we can reuse them if necessary.
+ std::map<Function*, void*> FunctionToStubMap;
+
+ /// StubToFunctionMap - Keep track of the function that each stub
+ /// corresponds to.
+ std::map<void*, Function*> StubToFunctionMap;
+
+ public:
+ std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
+ assert(locked.holds(TheJIT->lock));
+ return FunctionToStubMap;
+ }
+
+ std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
+ assert(locked.holds(TheJIT->lock));
+ return StubToFunctionMap;
+ }
+ };
+
+ /// JITResolver - Keep track of, and resolve, call sites for functions that
+ /// have not yet been compiled.
+ class JITResolver {
+ /// LazyResolverFn - The target lazy resolver function that we actually
+ /// rewrite instructions to use.
+ TargetJITInfo::LazyResolverFn LazyResolverFn;
+
+ JITResolverState state;
+
+ /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
+ /// external functions.
+ std::map<void*, void*> ExternalFnToStubMap;
+
+ //map addresses to indexes in the GOT
+ std::map<void*, unsigned> revGOTMap;
+ unsigned nextGOTIndex;
+
+ static JITResolver *TheJITResolver;
+ public:
+ JITResolver(JIT &jit) : nextGOTIndex(0) {
+ TheJIT = &jit;
+
+ LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
+ assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
+ TheJITResolver = this;
+ }
+
+ ~JITResolver() {
+ TheJITResolver = 0;
+ }
+
+ /// getFunctionStub - This returns a pointer to a function stub, creating
+ /// one on demand as needed.
+ void *getFunctionStub(Function *F);
+
+ /// getExternalFunctionStub - Return a stub for the function at the
+ /// specified address, created lazily on demand.
+ void *getExternalFunctionStub(void *FnAddr);
+
+ /// AddCallbackAtLocation - If the target is capable of rewriting an
+ /// instruction without the use of a stub, record the location of the use so
+ /// we know which function is being used at the location.
+ void *AddCallbackAtLocation(Function *F, void *Location) {
+ MutexGuard locked(TheJIT->lock);
+ /// Get the target-specific JIT resolver function.
+ state.getStubToFunctionMap(locked)[Location] = F;
+ return (void*)(intptr_t)LazyResolverFn;
+ }
+
+ /// getGOTIndexForAddress - Return a new or existing index in the GOT for
+ /// and 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);
+
+ /// JITCompilerFn - This function is called to resolve a stub to a compiled
+ /// address. If the LLVM Function corresponding to the stub has not yet
+ /// been compiled, this function compiles it first.
+ static void *JITCompilerFn(void *Stub);
+ };
+}
+
+JITResolver *JITResolver::TheJITResolver = 0;
+
+#if (defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)) && \
+ defined(__APPLE__)
+extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
+#endif
+
+/// synchronizeICache - On some targets, the JIT emitted code must be
+/// explicitly refetched to ensure correct execution.
+static void synchronizeICache(const void *Addr, size_t len) {
+#if (defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)) && \
+ defined(__APPLE__)
+ sys_icache_invalidate(Addr, len);
+#endif
+}
+
+/// getFunctionStub - This returns a pointer to a function stub, creating
+/// one on demand as needed.
+void *JITResolver::getFunctionStub(Function *F) {
+ MutexGuard locked(TheJIT->lock);
+
+ // If we already have a stub for this function, recycle it.
+ void *&Stub = state.getFunctionToStubMap(locked)[F];
+ if (Stub) return Stub;
+
+ // Call the lazy resolver function unless we already KNOW it is an external
+ // function, in which case we just skip the lazy resolution step.
+ void *Actual = (void*)(intptr_t)LazyResolverFn;
+ if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode())
+ Actual = TheJIT->getPointerToFunction(F);
+
+ // Otherwise, codegen a new stub. For now, the stub will call the lazy
+ // resolver function.
+ Stub = TheJIT->getJITInfo().emitFunctionStub(Actual,
+ *TheJIT->getCodeEmitter());
+
+ if (Actual != (void*)(intptr_t)LazyResolverFn) {
+ // If we are getting the stub for an external function, we really want the
+ // address of the stub in the GlobalAddressMap for the JIT, not the address
+ // of the external function.
+ TheJIT->updateGlobalMapping(F, Stub);
+ }
+
+ // Invalidate the icache if necessary.
+ synchronizeICache(Stub, TheJIT->getCodeEmitter()->getCurrentPCValue() -
+ (intptr_t)Stub);
+
+ DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
+ << F->getName() << "'\n";
+
+ // Finally, keep track of the stub-to-Function mapping so that the
+ // JITCompilerFn knows which function to compile!
+ state.getStubToFunctionMap(locked)[Stub] = F;
+ return Stub;
+}
+
+/// getExternalFunctionStub - Return a stub for the function at the
+/// specified address, created lazily on demand.
+void *JITResolver::getExternalFunctionStub(void *FnAddr) {
+ // If we already have a stub for this function, recycle it.
+ void *&Stub = ExternalFnToStubMap[FnAddr];
+ if (Stub) return Stub;
+
+ Stub = TheJIT->getJITInfo().emitFunctionStub(FnAddr,
+ *TheJIT->getCodeEmitter());
+
+ // Invalidate the icache if necessary.
+ synchronizeICache(Stub, TheJIT->getCodeEmitter()->getCurrentPCValue() -
+ (intptr_t)Stub);
+
+ DOUT << "JIT: Stub emitted at [" << Stub
+ << "] for external function at '" << FnAddr << "'\n";
+ return Stub;
+}
+
+unsigned JITResolver::getGOTIndexForAddr(void* addr) {
+ unsigned idx = revGOTMap[addr];
+ if (!idx) {
+ idx = ++nextGOTIndex;
+ revGOTMap[addr] = idx;
+ DOUT << "Adding GOT entry " << idx
+ << " for addr " << addr << "\n";
+ // ((void**)MemMgr.getGOTBase())[idx] = addr;
+ }
+ return idx;
+}
+
+/// JITCompilerFn - This function is called when a lazy compilation stub has
+/// been entered. It looks up which function this stub corresponds to, compiles
+/// it if necessary, then returns the resultant function pointer.
+void *JITResolver::JITCompilerFn(void *Stub) {
+ JITResolver &JR = *TheJITResolver;
+
+ MutexGuard locked(TheJIT->lock);
+
+ // The address given to us for the stub may not be exactly right, it might be
+ // a little bit after the stub. As such, use upper_bound to find it.
+ std::map<void*, Function*>::iterator I =
+ JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
+ assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
+ "This is not a known stub!");
+ Function *F = (--I)->second;
+
+ // If we have already code generated the function, just return the address.
+ void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
+
+ if (!Result) {
+ // Otherwise we don't have it, do lazy compilation now.
+
+ // If lazy compilation is disabled, emit a useful error message and abort.
+ if (TheJIT->isLazyCompilationDisabled()) {
+ cerr << "LLVM JIT requested to do lazy compilation of function '"
+ << F->getName() << "' when lazy compiles are disabled!\n";
+ abort();
+ }
+
+ // We might like to remove the stub from the StubToFunction map.
+ // We can't do that! Multiple threads could be stuck, waiting to acquire the
+ // lock above. As soon as the 1st function finishes compiling the function,
+ // the next one will be released, and needs to be able to find the function
+ // it needs to call.
+ //JR.state.getStubToFunctionMap(locked).erase(I);
+
+ DOUT << "JIT: Lazily resolving function '" << F->getName()
+ << "' In stub ptr = " << Stub << " actual ptr = "
+ << I->first << "\n";
+
+ Result = TheJIT->getPointerToFunction(F);
+ }
+
+ // We don't need to reuse this stub in the future, as F is now compiled.
+ JR.state.getFunctionToStubMap(locked).erase(F);
+
+ // FIXME: We could rewrite all references to this stub if we knew them.
+
+ // What we will do is set the compiled function address to map to the
+ // same GOT entry as the stub so that later clients may update the GOT
+ // if they see it still using the stub address.
+ // Note: this is done so the Resolver doesn't have to manage GOT memory
+ // Do this without allocating map space if the target isn't using a GOT
+ if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
+ JR.revGOTMap[Result] = JR.revGOTMap[Stub];
+
+ return Result;
+}
+
+
+//===----------------------------------------------------------------------===//
+// JITEmitter code.
+//
+namespace {
+ /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
+ /// used to output functions to memory for execution.
+ class JITEmitter : public MachineCodeEmitter {
+ JITMemoryManager MemMgr;
+
+ // When outputting a function stub in the context of some other function, we
+ // save BufferBegin/BufferEnd/CurBufferPtr here.
+ unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
+
+ /// Relocations - These are the relocations that the function needs, as
+ /// emitted.
+ std::vector<MachineRelocation> Relocations;
+
+ /// MBBLocations - This vector is a mapping from MBB ID's to their address.
+ /// It is filled in by the StartMachineBasicBlock callback and queried by
+ /// the getMachineBasicBlockAddress callback.
+ std::vector<intptr_t> MBBLocations;
+
+ /// ConstantPool - The constant pool for the current function.
+ ///
+ MachineConstantPool *ConstantPool;
+
+ /// ConstantPoolBase - A pointer to the first entry in the constant pool.
+ ///
+ void *ConstantPoolBase;
+
+ /// JumpTable - The jump tables for the current function.
+ ///
+ MachineJumpTableInfo *JumpTable;
+
+ /// JumpTableBase - A pointer to the first entry in the jump table.
+ ///
+ void *JumpTableBase;
+
+ /// 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";
+ }
+
+ JITResolver &getJITResolver() { return Resolver; }
+
+ virtual void startFunction(MachineFunction &F);
+ virtual bool finishFunction(MachineFunction &F);
+
+ void emitConstantPool(MachineConstantPool *MCP);
+ void initJumpTableInfo(MachineJumpTableInfo *MJTI);
+ void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
+
+ virtual void startFunctionStub(unsigned StubSize, unsigned Alignment = 1);
+ virtual void* finishFunctionStub(const Function *F);
+
+ virtual void addRelocation(const MachineRelocation &MR) {
+ Relocations.push_back(MR);
+ }
+
+ virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
+ if (MBBLocations.size() <= (unsigned)MBB->getNumber())
+ MBBLocations.resize((MBB->getNumber()+1)*2);
+ MBBLocations[MBB->getNumber()] = getCurrentPCValue();
+ }
+
+ virtual intptr_t getConstantPoolEntryAddress(unsigned Entry) const;
+ virtual intptr_t getJumpTableEntryAddress(unsigned Entry) const;
+
+ virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
+ assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
+ MBBLocations[MBB->getNumber()] && "MBB not emitted!");
+ return MBBLocations[MBB->getNumber()];
+ }
+
+ /// deallocateMemForFunction - Deallocate all memory for the specified
+ /// function body.
+ void deallocateMemForFunction(Function *F) {
+ MemMgr.deallocateMemForFunction(F);
+ }
+ private:
+ void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
+ };
+}
+
+void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
+ bool DoesntNeedStub) {
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
+ /// FIXME: If we straightened things out, this could actually emit the
+ /// global immediately instead of queuing it for codegen later!
+ return TheJIT->getOrEmitGlobalVariable(GV);
+ }
+
+ // If we have already compiled the function, return a pointer to its body.
+ Function *F = cast<Function>(V);
+ void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
+ if (ResultPtr) return ResultPtr;
+
+ if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
+ // If this is an external function pointer, we can force the JIT to
+ // 'compile' it, which really just adds it to the map.
+ if (DoesntNeedStub)
+ return TheJIT->getPointerToFunction(F);
+
+ return Resolver.getFunctionStub(F);
+ }
+
+ // Okay, the function has not been compiled yet, if the target callback
+ // mechanism is capable of rewriting the instruction directly, prefer to do
+ // that instead of emitting a stub.
+ if (DoesntNeedStub)
+ return Resolver.AddCallbackAtLocation(F, Reference);
+
+ // Otherwise, we have to emit a lazy resolving stub.
+ return Resolver.getFunctionStub(F);
+}
+
+void JITEmitter::startFunction(MachineFunction &F) {
+ uintptr_t ActualSize;
+ BufferBegin = CurBufferPtr = MemMgr.startFunctionBody(ActualSize);
+ BufferEnd = BufferBegin+ActualSize;
+
+ // Ensure the constant pool/jump table info is at least 4-byte aligned.
+ emitAlignment(16);
+
+ emitConstantPool(F.getConstantPool());
+ initJumpTableInfo(F.getJumpTableInfo());
+
+ // About to start emitting the machine code for the function.
+ emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
+ TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
+
+ MBBLocations.clear();
+}
+
+bool JITEmitter::finishFunction(MachineFunction &F) {
+ if (CurBufferPtr == BufferEnd) {
+ // FIXME: Allocate more space, then try again.
+ cerr << "JIT: Ran out of space for generated machine code!\n";
+ abort();
+ }
+
+ emitJumpTableInfo(F.getJumpTableInfo());
+
+ // FnStart is the start of the text, not the start of the constant pool and
+ // other per-function data.
+ unsigned char *FnStart =
+ (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
+ unsigned char *FnEnd = CurBufferPtr;
+
+ MemMgr.endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
+ NumBytes += FnEnd-FnStart;
+
+ if (!Relocations.empty()) {
+ NumRelos += Relocations.size();
+
+ // Resolve the relocations to concrete pointers.
+ for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
+ MachineRelocation &MR = Relocations[i];
+ void *ResultPtr;
+ if (MR.isString()) {
+ ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
+
+ // If the target REALLY wants a stub for this function, emit it now.
+ if (!MR.doesntNeedFunctionStub())
+ ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
+ } else if (MR.isGlobalValue()) {
+ ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
+ BufferBegin+MR.getMachineCodeOffset(),
+ MR.doesntNeedFunctionStub());
+ } else if (MR.isBasicBlock()) {
+ ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
+ } else if (MR.isConstantPoolIndex()) {
+ ResultPtr=(void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
+ } else {
+ assert(MR.isJumpTableIndex());
+ ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
+ }
+
+ MR.setResultPointer(ResultPtr);
+
+ // if we are managing the GOT and the relocation wants an index,
+ // give it one
+ if (MemMgr.isManagingGOT() && MR.isGOTRelative()) {
+ unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
+ MR.setGOTIndex(idx);
+ if (((void**)MemMgr.getGOTBase())[idx] != ResultPtr) {
+ DOUT << "GOT was out of date for " << ResultPtr
+ << " pointing at " << ((void**)MemMgr.getGOTBase())[idx]
+ << "\n";
+ ((void**)MemMgr.getGOTBase())[idx] = ResultPtr;
+ }
+ }
+ }
+
+ TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
+ Relocations.size(), MemMgr.getGOTBase());
+ }
+
+ // Update the GOT entry for F to point to the new code.
+ if (MemMgr.isManagingGOT()) {
+ unsigned idx = Resolver.getGOTIndexForAddr((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;
+ }
+ }
+
+ // Invalidate the icache if necessary.
+ synchronizeICache(FnStart, FnEnd-FnStart);
+
+ DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
+ << "] Function: " << F.getFunction()->getName()
+ << ": " << (FnEnd-FnStart) << " bytes of text, "
+ << Relocations.size() << " relocations\n";
+ Relocations.clear();
+
+#ifndef NDEBUG
+ if (sys::hasDisassembler())
+ DOUT << "Disassembled code:\n"
+ << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
+#endif
+
+ return false;
+}
+
+void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
+ const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
+ if (Constants.empty()) return;
+
+ MachineConstantPoolEntry CPE = Constants.back();
+ unsigned Size = CPE.Offset;
+ const Type *Ty = CPE.isMachineConstantPoolEntry()
+ ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
+ Size += TheJIT->getTargetData()->getTypeSize(Ty);
+
+ ConstantPoolBase = allocateSpace(Size, 1 << MCP->getConstantPoolAlignment());
+ ConstantPool = MCP;
+
+ if (ConstantPoolBase == 0) return; // Buffer overflow.
+
+ // Initialize the memory for all of the constant pool entries.
+ for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
+ void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
+ if (Constants[i].isMachineConstantPoolEntry()) {
+ // FIXME: add support to lower machine constant pool values into bytes!
+ cerr << "Initialize memory with machine specific constant pool entry"
+ << " has not been implemented!\n";
+ abort();
+ }
+ TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
+ }
+}
+
+void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
+ const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+ if (JT.empty()) return;
+
+ unsigned NumEntries = 0;
+ for (unsigned i = 0, e = JT.size(); i != e; ++i)
+ NumEntries += JT[i].MBBs.size();
+
+ unsigned EntrySize = MJTI->getEntrySize();
+
+ // Just allocate space for all the jump tables now. We will fix up the actual
+ // MBB entries in the tables after we emit the code for each block, since then
+ // we will know the final locations of the MBBs in memory.
+ JumpTable = MJTI;
+ JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
+}
+
+void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
+ const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+ if (JT.empty() || JumpTableBase == 0) return;
+
+ if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
+ assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
+ // For each jump table, place the offset from the beginning of the table
+ // to the target address.
+ int *SlotPtr = (int*)JumpTableBase;
+
+ for (unsigned i = 0, e = JT.size(); i != e; ++i) {
+ const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
+ // Store the offset of the basic block for this jump table slot in the
+ // memory we allocated for the jump table in 'initJumpTableInfo'
+ intptr_t Base = (intptr_t)SlotPtr;
+ for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
+ *SlotPtr++ = (intptr_t)getMachineBasicBlockAddress(MBBs[mi]) - Base;
+ }
+ } else {
+ assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
+
+ // For each jump table, map each target in the jump table to the address of
+ // an emitted MachineBasicBlock.
+ intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
+
+ for (unsigned i = 0, e = JT.size(); i != e; ++i) {
+ const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
+ // Store the address of the basic block for this jump table slot in the
+ // memory we allocated for the jump table in 'initJumpTableInfo'
+ for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
+ *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
+ }
+ }
+}
+
+void JITEmitter::startFunctionStub(unsigned StubSize, unsigned Alignment) {
+ SavedBufferBegin = BufferBegin;
+ SavedBufferEnd = BufferEnd;
+ SavedCurBufferPtr = CurBufferPtr;
+
+ BufferBegin = CurBufferPtr = MemMgr.allocateStub(StubSize, Alignment);
+ BufferEnd = BufferBegin+StubSize+1;
+}
+
+void *JITEmitter::finishFunctionStub(const Function *F) {
+ NumBytes += getCurrentPCOffset();
+ std::swap(SavedBufferBegin, BufferBegin);
+ BufferEnd = SavedBufferEnd;
+ CurBufferPtr = SavedCurBufferPtr;
+ return SavedBufferBegin;
+}
+
+// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
+// in the constant pool that was last emitted with the 'emitConstantPool'
+// method.
+//
+intptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
+ assert(ConstantNum < ConstantPool->getConstants().size() &&
+ "Invalid ConstantPoolIndex!");
+ return (intptr_t)ConstantPoolBase +
+ ConstantPool->getConstants()[ConstantNum].Offset;
+}
+
+// getJumpTableEntryAddress - Return the address of the JumpTable with index
+// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
+//
+intptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
+ const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
+ assert(Index < JT.size() && "Invalid jump table index!");
+
+ unsigned Offset = 0;
+ unsigned EntrySize = JumpTable->getEntrySize();
+
+ for (unsigned i = 0; i < Index; ++i)
+ Offset += JT[i].MBBs.size();
+
+ Offset *= EntrySize;
+
+ return (intptr_t)((char *)JumpTableBase + Offset);
+}
+
+//===----------------------------------------------------------------------===//
+// Public interface to this file
+//===----------------------------------------------------------------------===//
+
+MachineCodeEmitter *JIT::createEmitter(JIT &jit) {
+ return new JITEmitter(jit);
+}
+
+// getPointerToNamedFunction - This function is used as a global wrapper to
+// JIT::getPointerToNamedFunction for the purpose of resolving symbols when
+// bugpoint is debugging the JIT. In that scenario, we are loading an .so and
+// need to resolve function(s) that are being mis-codegenerated, so we need to
+// resolve their addresses at runtime, and this is the way to do it.
+extern "C" {
+ void *getPointerToNamedFunction(const char *Name) {
+ if (Function *F = TheJIT->FindFunctionNamed(Name))
+ return TheJIT->getPointerToFunction(F);
+ return TheJIT->getPointerToNamedFunction(Name);
+ }
+}
+
+// getPointerToFunctionOrStub - If the specified function has been
+// code-gen'd, return a pointer to the function. If not, compile it, or use
+// a stub to implement lazy compilation if available.
+//
+void *JIT::getPointerToFunctionOrStub(Function *F) {
+ // If we have already code generated the function, just return the address.
+ if (void *Addr = getPointerToGlobalIfAvailable(F))
+ return Addr;
+
+ // Get a stub if the target supports it.
+ assert(dynamic_cast<JITEmitter*>(MCE) && "Unexpected MCE?");
+ JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
+ return JE->getJITResolver().getFunctionStub(F);
+}
+
+/// freeMachineCodeForFunction - release machine code memory for given Function.
+///
+void JIT::freeMachineCodeForFunction(Function *F) {
+ // Delete translation for this from the ExecutionEngine, so it will get
+ // retranslated next time it is used.
+ updateGlobalMapping(F, 0);
+
+ // Free the actual memory for the function body and related stuff.
+ assert(dynamic_cast<JITEmitter*>(MCE) && "Unexpected MCE?");
+ static_cast<JITEmitter*>(MCE)->deallocateMemForFunction(F);
+}
+