1 //===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a MachineCodeEmitter object that is used by the JIT to
11 // write machine code to memory and remember where relocatable values are.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "jit"
17 #include "llvm/Constant.h"
18 #include "llvm/Module.h"
19 #include "llvm/Type.h"
20 #include "llvm/CodeGen/MachineCodeEmitter.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineConstantPool.h"
23 #include "llvm/CodeGen/MachineJumpTableInfo.h"
24 #include "llvm/CodeGen/MachineRelocation.h"
25 #include "llvm/ExecutionEngine/GenericValue.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/Target/TargetJITInfo.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/ADT/Statistic.h"
30 #include "llvm/System/Memory.h"
37 Statistic<> NumBytes("jit", "Number of bytes of machine code compiled");
38 Statistic<> NumRelos("jit", "Number of relocations applied");
43 //===----------------------------------------------------------------------===//
44 // JITMemoryManager code.
47 /// JITMemoryManager - Manage memory for the JIT code generation in a logical,
48 /// sane way. This splits a large block of MAP_NORESERVE'd memory into two
49 /// sections, one for function stubs, one for the functions themselves. We
50 /// have to do this because we may need to emit a function stub while in the
51 /// middle of emitting a function, and we don't know how large the function we
52 /// are emitting is. This never bothers to release the memory, because when
53 /// we are ready to destroy the JIT, the program exits.
54 class JITMemoryManager {
55 std::list<sys::MemoryBlock> Blocks; // List of blocks allocated by the JIT
56 unsigned char *FunctionBase; // Start of the function body area
57 unsigned char *ConstantBase; // Memory allocated for constant pools
58 unsigned char *CurStubPtr, *CurFunctionPtr, *CurConstantPtr;
59 unsigned char *GOTBase; // Target Specific reserved memory
61 // centralize memory block allocation
62 sys::MemoryBlock getNewMemoryBlock(unsigned size);
64 JITMemoryManager(bool useGOT);
67 inline unsigned char *allocateStub(unsigned StubSize);
68 inline unsigned char *allocateConstant(unsigned ConstantSize,
70 inline unsigned char *startFunctionBody();
71 inline void endFunctionBody(unsigned char *FunctionEnd);
73 unsigned char *getGOTBase() const {
76 bool isManagingGOT() const {
77 return GOTBase != NULL;
82 JITMemoryManager::JITMemoryManager(bool useGOT) {
83 // Allocate a 16M block of memory for functions
84 sys::MemoryBlock FunBlock = getNewMemoryBlock(16 << 20);
85 // Allocate a 1M block of memory for Constants
86 sys::MemoryBlock ConstBlock = getNewMemoryBlock(1 << 20);
88 Blocks.push_front(FunBlock);
89 Blocks.push_front(ConstBlock);
91 FunctionBase = reinterpret_cast<unsigned char*>(FunBlock.base());
92 ConstantBase = reinterpret_cast<unsigned char*>(ConstBlock.base());
94 // Allocate stubs backwards from the base, allocate functions forward
96 CurStubPtr = CurFunctionPtr = FunctionBase + 512*1024;// Use 512k for stubs
98 CurConstantPtr = ConstantBase + ConstBlock.size();
102 if (useGOT) GOTBase = (unsigned char*)malloc(sizeof(void*) * 8192);
105 JITMemoryManager::~JITMemoryManager() {
106 for (std::list<sys::MemoryBlock>::iterator ib = Blocks.begin(),
107 ie = Blocks.end(); ib != ie; ++ib)
108 sys::Memory::ReleaseRWX(*ib);
112 unsigned char *JITMemoryManager::allocateStub(unsigned StubSize) {
113 CurStubPtr -= StubSize;
114 if (CurStubPtr < FunctionBase) {
115 // FIXME: allocate a new block
116 std::cerr << "JIT ran out of memory for function stubs!\n";
122 unsigned char *JITMemoryManager::allocateConstant(unsigned ConstantSize,
123 unsigned Alignment) {
124 // Reserve space and align pointer.
125 CurConstantPtr -= ConstantSize;
127 (unsigned char *)((intptr_t)CurConstantPtr & ~((intptr_t)Alignment - 1));
129 if (CurConstantPtr < ConstantBase) {
130 //Either allocate another MB or 2xConstantSize
131 sys::MemoryBlock ConstBlock = getNewMemoryBlock(2 * ConstantSize);
132 ConstantBase = reinterpret_cast<unsigned char*>(ConstBlock.base());
133 CurConstantPtr = ConstantBase + ConstBlock.size();
134 return allocateConstant(ConstantSize, Alignment);
136 return CurConstantPtr;
139 unsigned char *JITMemoryManager::startFunctionBody() {
140 // Round up to an even multiple of 8 bytes, this should eventually be target
142 return (unsigned char*)(((intptr_t)CurFunctionPtr + 7) & ~7);
145 void JITMemoryManager::endFunctionBody(unsigned char *FunctionEnd) {
146 assert(FunctionEnd > CurFunctionPtr);
147 CurFunctionPtr = FunctionEnd;
150 sys::MemoryBlock JITMemoryManager::getNewMemoryBlock(unsigned size) {
151 const sys::MemoryBlock* BOld = 0;
153 BOld = &Blocks.front();
154 //never allocate less than 1 MB
157 B = sys::Memory::AllocateRWX(std::max(((unsigned)1 << 20), size), BOld);
158 } catch (std::string& err) {
159 std::cerr << "Allocation failed when allocating new memory in the JIT\n";
160 std::cerr << err << "\n";
163 Blocks.push_front(B);
167 //===----------------------------------------------------------------------===//
168 // JIT lazy compilation code.
171 class JITResolverState {
173 /// FunctionToStubMap - Keep track of the stub created for a particular
174 /// function so that we can reuse them if necessary.
175 std::map<Function*, void*> FunctionToStubMap;
177 /// StubToFunctionMap - Keep track of the function that each stub
179 std::map<void*, Function*> StubToFunctionMap;
182 std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
183 assert(locked.holds(TheJIT->lock));
184 return FunctionToStubMap;
187 std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
188 assert(locked.holds(TheJIT->lock));
189 return StubToFunctionMap;
193 /// JITResolver - Keep track of, and resolve, call sites for functions that
194 /// have not yet been compiled.
196 /// MCE - The MachineCodeEmitter to use to emit stubs with.
197 MachineCodeEmitter &MCE;
199 /// LazyResolverFn - The target lazy resolver function that we actually
200 /// rewrite instructions to use.
201 TargetJITInfo::LazyResolverFn LazyResolverFn;
203 JITResolverState state;
205 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
206 /// external functions.
207 std::map<void*, void*> ExternalFnToStubMap;
209 //map addresses to indexes in the GOT
210 std::map<void*, unsigned> revGOTMap;
211 unsigned nextGOTIndex;
214 JITResolver(MachineCodeEmitter &mce) : MCE(mce), nextGOTIndex(0) {
216 TheJIT->getJITInfo().getLazyResolverFunction(JITCompilerFn);
219 /// getFunctionStub - This returns a pointer to a function stub, creating
220 /// one on demand as needed.
221 void *getFunctionStub(Function *F);
223 /// getExternalFunctionStub - Return a stub for the function at the
224 /// specified address, created lazily on demand.
225 void *getExternalFunctionStub(void *FnAddr);
227 /// AddCallbackAtLocation - If the target is capable of rewriting an
228 /// instruction without the use of a stub, record the location of the use so
229 /// we know which function is being used at the location.
230 void *AddCallbackAtLocation(Function *F, void *Location) {
231 MutexGuard locked(TheJIT->lock);
232 /// Get the target-specific JIT resolver function.
233 state.getStubToFunctionMap(locked)[Location] = F;
234 return (void*)LazyResolverFn;
237 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
238 /// and address. This function only manages slots, it does not manage the
239 /// contents of the slots or the memory associated with the GOT.
240 unsigned getGOTIndexForAddr(void* addr);
242 /// JITCompilerFn - This function is called to resolve a stub to a compiled
243 /// address. If the LLVM Function corresponding to the stub has not yet
244 /// been compiled, this function compiles it first.
245 static void *JITCompilerFn(void *Stub);
249 /// getJITResolver - This function returns the one instance of the JIT resolver.
251 static JITResolver &getJITResolver(MachineCodeEmitter *MCE = 0) {
252 static JITResolver TheJITResolver(*MCE);
253 return TheJITResolver;
256 /// getFunctionStub - This returns a pointer to a function stub, creating
257 /// one on demand as needed.
258 void *JITResolver::getFunctionStub(Function *F) {
259 MutexGuard locked(TheJIT->lock);
261 // If we already have a stub for this function, recycle it.
262 void *&Stub = state.getFunctionToStubMap(locked)[F];
263 if (Stub) return Stub;
265 // Call the lazy resolver function unless we already KNOW it is an external
266 // function, in which case we just skip the lazy resolution step.
267 void *Actual = (void*)LazyResolverFn;
268 if (F->isExternal() && F->hasExternalLinkage())
269 Actual = TheJIT->getPointerToFunction(F);
271 // Otherwise, codegen a new stub. For now, the stub will call the lazy
272 // resolver function.
273 Stub = TheJIT->getJITInfo().emitFunctionStub(Actual, MCE);
275 if (Actual != (void*)LazyResolverFn) {
276 // If we are getting the stub for an external function, we really want the
277 // address of the stub in the GlobalAddressMap for the JIT, not the address
278 // of the external function.
279 TheJIT->updateGlobalMapping(F, Stub);
282 DEBUG(std::cerr << "JIT: Stub emitted at [" << Stub << "] for function '"
283 << F->getName() << "'\n");
285 // Finally, keep track of the stub-to-Function mapping so that the
286 // JITCompilerFn knows which function to compile!
287 state.getStubToFunctionMap(locked)[Stub] = F;
291 /// getExternalFunctionStub - Return a stub for the function at the
292 /// specified address, created lazily on demand.
293 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
294 // If we already have a stub for this function, recycle it.
295 void *&Stub = ExternalFnToStubMap[FnAddr];
296 if (Stub) return Stub;
298 Stub = TheJIT->getJITInfo().emitFunctionStub(FnAddr, MCE);
299 DEBUG(std::cerr << "JIT: Stub emitted at [" << Stub
300 << "] for external function at '" << FnAddr << "'\n");
304 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
305 unsigned idx = revGOTMap[addr];
307 idx = ++nextGOTIndex;
308 revGOTMap[addr] = idx;
309 DEBUG(std::cerr << "Adding GOT entry " << idx
310 << " for addr " << addr << "\n");
311 // ((void**)MemMgr.getGOTBase())[idx] = addr;
316 /// JITCompilerFn - This function is called when a lazy compilation stub has
317 /// been entered. It looks up which function this stub corresponds to, compiles
318 /// it if necessary, then returns the resultant function pointer.
319 void *JITResolver::JITCompilerFn(void *Stub) {
320 JITResolver &JR = getJITResolver();
322 MutexGuard locked(TheJIT->lock);
324 // The address given to us for the stub may not be exactly right, it might be
325 // a little bit after the stub. As such, use upper_bound to find it.
326 std::map<void*, Function*>::iterator I =
327 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
328 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
329 "This is not a known stub!");
330 Function *F = (--I)->second;
332 // We might like to remove the stub from the StubToFunction map.
333 // We can't do that! Multiple threads could be stuck, waiting to acquire the
334 // lock above. As soon as the 1st function finishes compiling the function,
335 // the next one will be released, and needs to be able to find the function it
337 //JR.state.getStubToFunctionMap(locked).erase(I);
339 DEBUG(std::cerr << "JIT: Lazily resolving function '" << F->getName()
340 << "' In stub ptr = " << Stub << " actual ptr = "
341 << I->first << "\n");
343 void *Result = TheJIT->getPointerToFunction(F);
345 // We don't need to reuse this stub in the future, as F is now compiled.
346 JR.state.getFunctionToStubMap(locked).erase(F);
348 // FIXME: We could rewrite all references to this stub if we knew them.
350 // What we will do is set the compiled function address to map to the
351 // same GOT entry as the stub so that later clients may update the GOT
352 // if they see it still using the stub address.
353 // Note: this is done so the Resolver doesn't have to manage GOT memory
354 // Do this without allocating map space if the target isn't using a GOT
355 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
356 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
362 // getPointerToFunctionOrStub - If the specified function has been
363 // code-gen'd, return a pointer to the function. If not, compile it, or use
364 // a stub to implement lazy compilation if available.
366 void *JIT::getPointerToFunctionOrStub(Function *F) {
367 // If we have already code generated the function, just return the address.
368 if (void *Addr = getPointerToGlobalIfAvailable(F))
371 // Get a stub if the target supports it
372 return getJITResolver(MCE).getFunctionStub(F);
377 //===----------------------------------------------------------------------===//
381 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
382 /// used to output functions to memory for execution.
383 class JITEmitter : public MachineCodeEmitter {
384 JITMemoryManager MemMgr;
386 // When outputting a function stub in the context of some other function, we
387 // save BufferBegin/BufferEnd/CurBufferPtr here.
388 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
390 /// Relocations - These are the relocations that the function needs, as
392 std::vector<MachineRelocation> Relocations;
394 /// ConstantPool - The constant pool for the current function.
396 MachineConstantPool *ConstantPool;
398 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
400 void *ConstantPoolBase;
402 /// ConstantPool - The constant pool for the current function.
404 MachineJumpTableInfo *JumpTable;
406 /// JumpTableBase - A pointer to the first entry in the jump table.
410 JITEmitter(JIT &jit) : MemMgr(jit.getJITInfo().needsGOT()) {
412 DEBUG(if (MemMgr.isManagingGOT()) std::cerr << "JIT is managing a GOT\n");
415 virtual void startFunction(MachineFunction &F);
416 virtual bool finishFunction(MachineFunction &F);
417 virtual void emitConstantPool(MachineConstantPool *MCP);
418 virtual void initJumpTableInfo(MachineJumpTableInfo *MJTI);
419 virtual void emitJumpTableInfo(MachineJumpTableInfo *MJTI,
420 std::map<MachineBasicBlock*,uint64_t> &MBBM);
421 virtual void startFunctionStub(unsigned StubSize);
422 virtual void* finishFunctionStub(const Function *F);
424 virtual void addRelocation(const MachineRelocation &MR) {
425 Relocations.push_back(MR);
428 virtual uint64_t getConstantPoolEntryAddress(unsigned Entry);
429 virtual uint64_t getJumpTableEntryAddress(unsigned Entry);
432 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
436 MachineCodeEmitter *JIT::createEmitter(JIT &jit) {
437 return new JITEmitter(jit);
440 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
441 bool DoesntNeedStub) {
442 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
443 /// FIXME: If we straightened things out, this could actually emit the
444 /// global immediately instead of queuing it for codegen later!
445 return TheJIT->getOrEmitGlobalVariable(GV);
448 // If we have already compiled the function, return a pointer to its body.
449 Function *F = cast<Function>(V);
450 void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
451 if (ResultPtr) return ResultPtr;
453 if (F->hasExternalLinkage() && F->isExternal()) {
454 // If this is an external function pointer, we can force the JIT to
455 // 'compile' it, which really just adds it to the map.
457 return TheJIT->getPointerToFunction(F);
459 return getJITResolver(this).getFunctionStub(F);
462 // Okay, the function has not been compiled yet, if the target callback
463 // mechanism is capable of rewriting the instruction directly, prefer to do
464 // that instead of emitting a stub.
466 return getJITResolver(this).AddCallbackAtLocation(F, Reference);
468 // Otherwise, we have to emit a lazy resolving stub.
469 return getJITResolver(this).getFunctionStub(F);
472 void JITEmitter::startFunction(MachineFunction &F) {
473 BufferBegin = CurBufferPtr = MemMgr.startFunctionBody();
474 TheJIT->updateGlobalMapping(F.getFunction(), BufferBegin);
476 /// FIXME: implement out of space handling correctly!
477 BufferEnd = (unsigned char*)(intptr_t)~0ULL;
480 bool JITEmitter::finishFunction(MachineFunction &F) {
481 MemMgr.endFunctionBody(CurBufferPtr);
482 NumBytes += getCurrentPCOffset();
484 if (!Relocations.empty()) {
485 NumRelos += Relocations.size();
487 // Resolve the relocations to concrete pointers.
488 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
489 MachineRelocation &MR = Relocations[i];
492 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
494 // If the target REALLY wants a stub for this function, emit it now.
495 if (!MR.doesntNeedFunctionStub())
496 ResultPtr = getJITResolver(this).getExternalFunctionStub(ResultPtr);
497 } else if (MR.isGlobalValue())
498 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
499 BufferBegin+MR.getMachineCodeOffset(),
500 MR.doesntNeedFunctionStub());
501 else //ConstantPoolIndex
503 (void*)(intptr_t)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
505 MR.setResultPointer(ResultPtr);
507 // if we are managing the GOT and the relocation wants an index,
509 if (MemMgr.isManagingGOT() && !MR.isConstantPoolIndex() &&
510 MR.isGOTRelative()) {
511 unsigned idx = getJITResolver(this).getGOTIndexForAddr(ResultPtr);
513 if (((void**)MemMgr.getGOTBase())[idx] != ResultPtr) {
514 DEBUG(std::cerr << "GOT was out of date for " << ResultPtr
515 << " pointing at " << ((void**)MemMgr.getGOTBase())[idx]
517 ((void**)MemMgr.getGOTBase())[idx] = ResultPtr;
522 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
523 Relocations.size(), MemMgr.getGOTBase());
526 //Update the GOT entry for F to point to the new code.
527 if(MemMgr.isManagingGOT()) {
528 unsigned idx = getJITResolver(this).getGOTIndexForAddr((void*)BufferBegin);
529 if (((void**)MemMgr.getGOTBase())[idx] != (void*)BufferBegin) {
530 DEBUG(std::cerr << "GOT was out of date for " << (void*)BufferBegin
531 << " pointing at " << ((void**)MemMgr.getGOTBase())[idx] << "\n");
532 ((void**)MemMgr.getGOTBase())[idx] = (void*)BufferBegin;
536 DEBUG(std::cerr << "JIT: Finished CodeGen of [" << (void*)BufferBegin
537 << "] Function: " << F.getFunction()->getName()
538 << ": " << getCurrentPCOffset() << " bytes of text, "
539 << Relocations.size() << " relocations\n");
544 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
545 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
546 if (Constants.empty()) return;
548 unsigned Size = Constants.back().Offset;
549 Size += TheJIT->getTargetData().getTypeSize(Constants.back().Val->getType());
551 ConstantPoolBase = MemMgr.allocateConstant(Size,
552 1 << MCP->getConstantPoolAlignment());
555 // Initialize the memory for all of the constant pool entries.
556 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
557 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
558 TheJIT->InitializeMemory(Constants[i].Val, CAddr);
562 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
563 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
564 if (JT.empty()) return;
567 unsigned EntrySize = MJTI->getEntrySize();
568 for (unsigned i = 0, e = JT.size(); i != e; ++i)
569 Size += JT[i].MBBs.size() * EntrySize;
571 // Just allocate space for all the jump tables now. We will fix up the actual
572 // MBB entries in the tables after we emit the code for each block, since then
573 // we will know the final locations of the MBBs in memory.
575 JumpTableBase = MemMgr.allocateConstant(Size, MJTI->getAlignment());
578 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI,
579 std::map<MachineBasicBlock*,uint64_t> &MBBM){
580 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
581 if (JT.empty()) return;
584 unsigned EntrySize = MJTI->getEntrySize();
586 // For each jump table, map each target in the jump table to the address of
587 // an emitted MachineBasicBlock.
588 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
589 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
590 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
591 uint64_t addr = MBBM[MBBs[mi]];
594 if (EntrySize == 4) {
595 addrgv.UIntVal = addr;
597 } else if (EntrySize == 8) {
598 addrgv.ULongVal = addr;
601 assert(0 && "Unhandled jump table entry size!");
604 // Store the address of the basic block for this jump table slot in the
605 // memory we allocated for the jump table in 'initJumpTableInfo'
606 void *ptr = (void *)((char *)JumpTableBase + Offset);
607 TheJIT->StoreValueToMemory(addrgv, (GenericValue *)ptr, Ty);
613 void JITEmitter::startFunctionStub(unsigned StubSize) {
614 SavedBufferBegin = BufferBegin;
615 SavedBufferEnd = BufferEnd;
616 SavedCurBufferPtr = CurBufferPtr;
618 BufferBegin = CurBufferPtr = MemMgr.allocateStub(StubSize);
619 BufferEnd = BufferBegin+StubSize+1;
622 void *JITEmitter::finishFunctionStub(const Function *F) {
623 NumBytes += getCurrentPCOffset();
624 std::swap(SavedBufferBegin, BufferBegin);
625 BufferEnd = SavedBufferEnd;
626 CurBufferPtr = SavedCurBufferPtr;
627 return SavedBufferBegin;
630 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
631 // in the constant pool that was last emitted with the 'emitConstantPool'
634 uint64_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) {
635 assert(ConstantNum < ConstantPool->getConstants().size() &&
636 "Invalid ConstantPoolIndex!");
637 return (intptr_t)ConstantPoolBase +
638 ConstantPool->getConstants()[ConstantNum].Offset;
641 // getJumpTableEntryAddress - Return the address of the JumpTable with index
642 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
644 uint64_t JITEmitter::getJumpTableEntryAddress(unsigned Index) {
645 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
646 assert(Index < JT.size() && "Invalid jump table index!");
649 unsigned EntrySize = JumpTable->getEntrySize();
651 for (unsigned i = 0; i < Index; ++i)
652 Offset += JT[i].MBBs.size() * EntrySize;
654 return (intptr_t)((char *)JumpTableBase + Offset);
657 // getPointerToNamedFunction - This function is used as a global wrapper to
658 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
659 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
660 // need to resolve function(s) that are being mis-codegenerated, so we need to
661 // resolve their addresses at runtime, and this is the way to do it.
663 void *getPointerToNamedFunction(const char *Name) {
664 Module &M = TheJIT->getModule();
665 if (Function *F = M.getNamedFunction(Name))
666 return TheJIT->getPointerToFunction(F);
667 return TheJIT->getPointerToNamedFunction(Name);