1 //===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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 "JITDwarfEmitter.h"
18 #include "llvm/Constants.h"
19 #include "llvm/Module.h"
20 #include "llvm/DerivedTypes.h"
21 #include "llvm/CodeGen/JITCodeEmitter.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineConstantPool.h"
24 #include "llvm/CodeGen/MachineJumpTableInfo.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/CodeGen/MachineRelocation.h"
27 #include "llvm/ExecutionEngine/GenericValue.h"
28 #include "llvm/ExecutionEngine/JITEventListener.h"
29 #include "llvm/ExecutionEngine/JITMemoryManager.h"
30 #include "llvm/CodeGen/MachineCodeInfo.h"
31 #include "llvm/Target/TargetData.h"
32 #include "llvm/Target/TargetJITInfo.h"
33 #include "llvm/Target/TargetMachine.h"
34 #include "llvm/Target/TargetOptions.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/MutexGuard.h"
37 #include "llvm/Support/ValueHandle.h"
38 #include "llvm/System/Disassembler.h"
39 #include "llvm/System/Memory.h"
40 #include "llvm/Target/TargetInstrInfo.h"
41 #include "llvm/ADT/SmallPtrSet.h"
42 #include "llvm/ADT/SmallVector.h"
43 #include "llvm/ADT/Statistic.h"
50 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
51 STATISTIC(NumRelos, "Number of relocations applied");
52 static JIT *TheJIT = 0;
55 //===----------------------------------------------------------------------===//
56 // JIT lazy compilation code.
59 class JITResolverState {
61 typedef std::map<AssertingVH<Function>, void*> FunctionToStubMapTy;
62 typedef std::map<void*, Function*> StubToFunctionMapTy;
63 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
65 /// FunctionToStubMap - Keep track of the stub created for a particular
66 /// function so that we can reuse them if necessary.
67 FunctionToStubMapTy FunctionToStubMap;
69 /// StubToFunctionMap - Keep track of the function that each stub
71 StubToFunctionMapTy StubToFunctionMap;
73 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
74 /// particular GlobalVariable so that we can reuse them if necessary.
75 GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
78 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) {
79 assert(locked.holds(TheJIT->lock));
80 return FunctionToStubMap;
83 StubToFunctionMapTy& getStubToFunctionMap(const MutexGuard& locked) {
84 assert(locked.holds(TheJIT->lock));
85 return StubToFunctionMap;
88 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) {
89 assert(locked.holds(TheJIT->lock));
90 return GlobalToIndirectSymMap;
94 /// JITResolver - Keep track of, and resolve, call sites for functions that
95 /// have not yet been compiled.
97 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy;
98 typedef JITResolverState::StubToFunctionMapTy StubToFunctionMapTy;
99 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
101 /// LazyResolverFn - The target lazy resolver function that we actually
102 /// rewrite instructions to use.
103 TargetJITInfo::LazyResolverFn LazyResolverFn;
105 JITResolverState state;
107 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
108 /// external functions.
109 std::map<void*, void*> ExternalFnToStubMap;
111 /// revGOTMap - map addresses to indexes in the GOT
112 std::map<void*, unsigned> revGOTMap;
113 unsigned nextGOTIndex;
115 static JITResolver *TheJITResolver;
117 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
120 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
121 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
122 TheJITResolver = this;
129 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
130 /// if it has already been created.
131 void *getFunctionStubIfAvailable(Function *F);
133 /// getFunctionStub - This returns a pointer to a function stub, creating
134 /// one on demand as needed. If empty is true, create a function stub
135 /// pointing at address 0, to be filled in later.
136 void *getFunctionStub(Function *F);
138 /// getExternalFunctionStub - Return a stub for the function at the
139 /// specified address, created lazily on demand.
140 void *getExternalFunctionStub(void *FnAddr);
142 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
143 /// specified GV address.
144 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
146 /// AddCallbackAtLocation - If the target is capable of rewriting an
147 /// instruction without the use of a stub, record the location of the use so
148 /// we know which function is being used at the location.
149 void *AddCallbackAtLocation(Function *F, void *Location) {
150 MutexGuard locked(TheJIT->lock);
151 /// Get the target-specific JIT resolver function.
152 state.getStubToFunctionMap(locked)[Location] = F;
153 return (void*)(intptr_t)LazyResolverFn;
156 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
157 SmallVectorImpl<void*> &Ptrs);
159 GlobalValue *invalidateStub(void *Stub);
161 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
162 /// an address. This function only manages slots, it does not manage the
163 /// contents of the slots or the memory associated with the GOT.
164 unsigned getGOTIndexForAddr(void *addr);
166 /// JITCompilerFn - This function is called to resolve a stub to a compiled
167 /// address. If the LLVM Function corresponding to the stub has not yet
168 /// been compiled, this function compiles it first.
169 static void *JITCompilerFn(void *Stub);
173 JITResolver *JITResolver::TheJITResolver = 0;
175 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
176 /// if it has already been created.
177 void *JITResolver::getFunctionStubIfAvailable(Function *F) {
178 MutexGuard locked(TheJIT->lock);
180 // If we already have a stub for this function, recycle it.
181 void *&Stub = state.getFunctionToStubMap(locked)[F];
185 /// getFunctionStub - This returns a pointer to a function stub, creating
186 /// one on demand as needed.
187 void *JITResolver::getFunctionStub(Function *F) {
188 MutexGuard locked(TheJIT->lock);
190 // If we already have a stub for this function, recycle it.
191 void *&Stub = state.getFunctionToStubMap(locked)[F];
192 if (Stub) return Stub;
194 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which
195 // case we must resolve the symbol now.
196 void *Actual = TheJIT->isLazyCompilationDisabled()
197 ? (void *)0 : (void *)(intptr_t)LazyResolverFn;
199 // If this is an external declaration, attempt to resolve the address now
200 // to place in the stub.
201 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
202 Actual = TheJIT->getPointerToFunction(F);
204 // If we resolved the symbol to a null address (eg. a weak external)
205 // don't emit a stub. Return a null pointer to the application. If dlsym
206 // stubs are enabled, not being able to resolve the address is not
208 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
211 // Codegen a new stub, calling the lazy resolver or the actual address of the
212 // external function, if it was resolved.
213 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
214 *TheJIT->getCodeEmitter());
216 if (Actual != (void*)(intptr_t)LazyResolverFn) {
217 // If we are getting the stub for an external function, we really want the
218 // address of the stub in the GlobalAddressMap for the JIT, not the address
219 // of the external function.
220 TheJIT->updateGlobalMapping(F, Stub);
223 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
224 << F->getName() << "'\n";
226 // Finally, keep track of the stub-to-Function mapping so that the
227 // JITCompilerFn knows which function to compile!
228 state.getStubToFunctionMap(locked)[Stub] = F;
230 // If we are JIT'ing non-lazily but need to call a function that does not
231 // exist yet, add it to the JIT's work list so that we can fill in the stub
233 if (!Actual && TheJIT->isLazyCompilationDisabled())
234 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
235 TheJIT->addPendingFunction(F);
240 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
242 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
243 MutexGuard locked(TheJIT->lock);
245 // If we already have a stub for this global variable, recycle it.
246 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
247 if (IndirectSym) return IndirectSym;
249 // Otherwise, codegen a new indirect symbol.
250 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
251 *TheJIT->getCodeEmitter());
253 DOUT << "JIT: Indirect symbol emitted at [" << IndirectSym << "] for GV '"
254 << GV->getName() << "'\n";
259 /// getExternalFunctionStub - Return a stub for the function at the
260 /// specified address, created lazily on demand.
261 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
262 // If we already have a stub for this function, recycle it.
263 void *&Stub = ExternalFnToStubMap[FnAddr];
264 if (Stub) return Stub;
266 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
267 *TheJIT->getCodeEmitter());
269 DOUT << "JIT: Stub emitted at [" << Stub
270 << "] for external function at '" << FnAddr << "'\n";
274 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
275 unsigned idx = revGOTMap[addr];
277 idx = ++nextGOTIndex;
278 revGOTMap[addr] = idx;
279 DOUT << "JIT: Adding GOT entry " << idx << " for addr [" << addr << "]\n";
284 void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
285 SmallVectorImpl<void*> &Ptrs) {
286 MutexGuard locked(TheJIT->lock);
288 FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
289 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
291 for (FunctionToStubMapTy::iterator i = FM.begin(), e = FM.end(); i != e; ++i){
292 Function *F = i->first;
293 if (F->isDeclaration() && F->hasExternalLinkage()) {
294 GVs.push_back(i->first);
295 Ptrs.push_back(i->second);
298 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
300 GVs.push_back(i->first);
301 Ptrs.push_back(i->second);
305 GlobalValue *JITResolver::invalidateStub(void *Stub) {
306 MutexGuard locked(TheJIT->lock);
308 FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
309 StubToFunctionMapTy &SM = state.getStubToFunctionMap(locked);
310 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
312 // Look up the cheap way first, to see if it's a function stub we are
313 // invalidating. If so, remove it from both the forward and reverse maps.
314 if (SM.find(Stub) != SM.end()) {
315 Function *F = SM[Stub];
321 // Otherwise, it might be an indirect symbol stub. Find it and remove it.
322 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
324 if (i->second != Stub)
326 GlobalValue *GV = i->first;
331 // Lastly, check to see if it's in the ExternalFnToStubMap.
332 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
333 e = ExternalFnToStubMap.end(); i != e; ++i) {
334 if (i->second != Stub)
336 ExternalFnToStubMap.erase(i);
343 /// JITCompilerFn - This function is called when a lazy compilation stub has
344 /// been entered. It looks up which function this stub corresponds to, compiles
345 /// it if necessary, then returns the resultant function pointer.
346 void *JITResolver::JITCompilerFn(void *Stub) {
347 JITResolver &JR = *TheJITResolver;
353 // Only lock for getting the Function. The call getPointerToFunction made
354 // in this function might trigger function materializing, which requires
355 // JIT lock to be unlocked.
356 MutexGuard locked(TheJIT->lock);
358 // The address given to us for the stub may not be exactly right, it might be
359 // a little bit after the stub. As such, use upper_bound to find it.
360 StubToFunctionMapTy::iterator I =
361 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
362 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
363 "This is not a known stub!");
365 ActualPtr = I->first;
368 // If we have already code generated the function, just return the address.
369 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
372 // Otherwise we don't have it, do lazy compilation now.
374 // If lazy compilation is disabled, emit a useful error message and abort.
375 if (TheJIT->isLazyCompilationDisabled()) {
376 cerr << "LLVM JIT requested to do lazy compilation of function '"
377 << F->getName() << "' when lazy compiles are disabled!\n";
381 // We might like to remove the stub from the StubToFunction map.
382 // We can't do that! Multiple threads could be stuck, waiting to acquire the
383 // lock above. As soon as the 1st function finishes compiling the function,
384 // the next one will be released, and needs to be able to find the function
386 //JR.state.getStubToFunctionMap(locked).erase(I);
388 DOUT << "JIT: Lazily resolving function '" << F->getName()
389 << "' In stub ptr = " << Stub << " actual ptr = "
390 << ActualPtr << "\n";
392 Result = TheJIT->getPointerToFunction(F);
395 // Reacquire the lock to erase the stub in the map.
396 MutexGuard locked(TheJIT->lock);
398 // We don't need to reuse this stub in the future, as F is now compiled.
399 JR.state.getFunctionToStubMap(locked).erase(F);
401 // FIXME: We could rewrite all references to this stub if we knew them.
403 // What we will do is set the compiled function address to map to the
404 // same GOT entry as the stub so that later clients may update the GOT
405 // if they see it still using the stub address.
406 // Note: this is done so the Resolver doesn't have to manage GOT memory
407 // Do this without allocating map space if the target isn't using a GOT
408 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
409 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
414 //===----------------------------------------------------------------------===//
418 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
419 /// used to output functions to memory for execution.
420 class JITEmitter : public JITCodeEmitter {
421 JITMemoryManager *MemMgr;
423 // When outputting a function stub in the context of some other function, we
424 // save BufferBegin/BufferEnd/CurBufferPtr here.
425 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
427 /// Relocations - These are the relocations that the function needs, as
429 std::vector<MachineRelocation> Relocations;
431 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
432 /// It is filled in by the StartMachineBasicBlock callback and queried by
433 /// the getMachineBasicBlockAddress callback.
434 std::vector<uintptr_t> MBBLocations;
436 /// ConstantPool - The constant pool for the current function.
438 MachineConstantPool *ConstantPool;
440 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
442 void *ConstantPoolBase;
444 /// ConstPoolAddresses - Addresses of individual constant pool entries.
446 SmallVector<uintptr_t, 8> ConstPoolAddresses;
448 /// JumpTable - The jump tables for the current function.
450 MachineJumpTableInfo *JumpTable;
452 /// JumpTableBase - A pointer to the first entry in the jump table.
456 /// Resolver - This contains info about the currently resolved functions.
457 JITResolver Resolver;
459 /// DE - The dwarf emitter for the jit.
462 /// LabelLocations - This vector is a mapping from Label ID's to their
464 std::vector<uintptr_t> LabelLocations;
466 /// MMI - Machine module info for exception informations
467 MachineModuleInfo* MMI;
469 // GVSet - a set to keep track of which globals have been seen
470 SmallPtrSet<const GlobalVariable*, 8> GVSet;
472 // CurFn - The llvm function being emitted. Only valid during
474 const Function *CurFn;
476 // CurFnStubUses - For a given Function, a vector of stubs that it
477 // references. This facilitates the JIT detecting that a stub is no
478 // longer used, so that it may be deallocated.
479 DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
481 // StubFnRefs - For a given pointer to a stub, a set of Functions which
482 // reference the stub. When the count of a stub's references drops to zero,
483 // the stub is unused.
484 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
486 // ExtFnStubs - A map of external function names to stubs which have entries
487 // in the JITResolver's ExternalFnToStubMap.
488 StringMap<void *> ExtFnStubs;
491 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit), CurFn(0) {
492 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
493 if (jit.getJITInfo().needsGOT()) {
494 MemMgr->AllocateGOT();
495 DOUT << "JIT is managing a GOT\n";
498 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
502 if (ExceptionHandling) delete DE;
505 /// classof - Methods for support type inquiry through isa, cast, and
508 static inline bool classof(const JITEmitter*) { return true; }
509 static inline bool classof(const MachineCodeEmitter*) { return true; }
511 JITResolver &getJITResolver() { return Resolver; }
513 virtual void startFunction(MachineFunction &F);
514 virtual bool finishFunction(MachineFunction &F);
516 void emitConstantPool(MachineConstantPool *MCP);
517 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
518 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
520 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
521 unsigned Alignment = 1);
522 virtual void startGVStub(const GlobalValue* GV, void *Buffer,
524 virtual void* finishGVStub(const GlobalValue *GV);
526 /// allocateSpace - Reserves space in the current block if any, or
527 /// allocate a new one of the given size.
528 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
530 virtual void addRelocation(const MachineRelocation &MR) {
531 Relocations.push_back(MR);
534 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
535 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
536 MBBLocations.resize((MBB->getNumber()+1)*2);
537 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
538 DOUT << "JIT: Emitting BB" << MBB->getNumber() << " at ["
539 << (void*) getCurrentPCValue() << "]\n";
542 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
543 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
545 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
546 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
547 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
548 return MBBLocations[MBB->getNumber()];
551 /// deallocateMemForFunction - Deallocate all memory for the specified
553 void deallocateMemForFunction(Function *F);
555 /// AddStubToCurrentFunction - Mark the current function being JIT'd as
556 /// using the stub at the specified address. Allows
557 /// deallocateMemForFunction to also remove stubs no longer referenced.
558 void AddStubToCurrentFunction(void *Stub);
560 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
561 /// MachineRelocations that reference external functions by name.
562 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
564 virtual void emitLabel(uint64_t LabelID) {
565 if (LabelLocations.size() <= LabelID)
566 LabelLocations.resize((LabelID+1)*2);
567 LabelLocations[LabelID] = getCurrentPCValue();
570 virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
571 assert(LabelLocations.size() > (unsigned)LabelID &&
572 LabelLocations[LabelID] && "Label not emitted!");
573 return LabelLocations[LabelID];
576 virtual void setModuleInfo(MachineModuleInfo* Info) {
578 if (ExceptionHandling) DE->setModuleInfo(Info);
581 void setMemoryExecutable(void) {
582 MemMgr->setMemoryExecutable();
585 JITMemoryManager *getMemMgr(void) const { return MemMgr; }
588 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
589 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
591 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
592 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
593 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
594 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
598 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
599 bool DoesntNeedStub) {
600 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
601 return TheJIT->getOrEmitGlobalVariable(GV);
603 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
604 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
606 // If we have already compiled the function, return a pointer to its body.
607 Function *F = cast<Function>(V);
609 if (!DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) {
610 // Return the function stub if it's already created.
611 ResultPtr = Resolver.getFunctionStubIfAvailable(F);
613 AddStubToCurrentFunction(ResultPtr);
615 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
617 if (ResultPtr) return ResultPtr;
619 // If this is an external function pointer, we can force the JIT to
620 // 'compile' it, which really just adds it to the map. In dlsym mode,
621 // external functions are forced through a stub, regardless of reloc type.
622 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
623 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
624 return TheJIT->getPointerToFunction(F);
626 // Okay, the function has not been compiled yet, if the target callback
627 // mechanism is capable of rewriting the instruction directly, prefer to do
628 // that instead of emitting a stub. This uses the lazy resolver, so is not
629 // legal if lazy compilation is disabled.
630 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
631 return Resolver.AddCallbackAtLocation(F, Reference);
633 // Otherwise, we have to emit a stub.
634 void *StubAddr = Resolver.getFunctionStub(F);
636 // Add the stub to the current function's list of referenced stubs, so we can
637 // deallocate them if the current function is ever freed. It's possible to
638 // return null from getFunctionStub in the case of a weak extern that fails
641 AddStubToCurrentFunction(StubAddr);
646 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
648 // Make sure GV is emitted first, and create a stub containing the fully
650 void *GVAddress = getPointerToGlobal(V, Reference, true);
651 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
653 // Add the stub to the current function's list of referenced stubs, so we can
654 // deallocate them if the current function is ever freed.
655 AddStubToCurrentFunction(StubAddr);
660 void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
661 if (!TheJIT->areDlsymStubsEnabled())
664 assert(CurFn && "Stub added to current function, but current function is 0!");
666 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
667 StubsUsed.push_back(StubAddr);
669 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
670 FnRefs.insert(CurFn);
673 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
674 const TargetData *TD) {
675 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
676 if (Constants.empty()) return 0;
679 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
680 MachineConstantPoolEntry CPE = Constants[i];
681 unsigned AlignMask = CPE.getAlignment() - 1;
682 Size = (Size + AlignMask) & ~AlignMask;
683 const Type *Ty = CPE.getType();
684 Size += TD->getTypeAllocSize(Ty);
689 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
690 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
691 if (JT.empty()) return 0;
693 unsigned NumEntries = 0;
694 for (unsigned i = 0, e = JT.size(); i != e; ++i)
695 NumEntries += JT[i].MBBs.size();
697 unsigned EntrySize = MJTI->getEntrySize();
699 return NumEntries * EntrySize;
702 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
703 if (Alignment == 0) Alignment = 1;
704 // Since we do not know where the buffer will be allocated, be pessimistic.
705 return Size + Alignment;
708 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
709 /// into the running total Size.
711 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
712 const Type *ElTy = GV->getType()->getElementType();
713 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy);
715 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
716 DOUT << "JIT: Adding in size " << GVSize << " alignment " << GVAlign;
718 // Assume code section ends with worst possible alignment, so first
719 // variable needs maximal padding.
722 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
727 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
728 /// but are referenced from the constant; put them in GVSet and add their
729 /// size into the running total Size.
731 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
733 // If its undefined, return the garbage.
734 if (isa<UndefValue>(C))
737 // If the value is a ConstantExpr
738 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
739 Constant *Op0 = CE->getOperand(0);
740 switch (CE->getOpcode()) {
741 case Instruction::GetElementPtr:
742 case Instruction::Trunc:
743 case Instruction::ZExt:
744 case Instruction::SExt:
745 case Instruction::FPTrunc:
746 case Instruction::FPExt:
747 case Instruction::UIToFP:
748 case Instruction::SIToFP:
749 case Instruction::FPToUI:
750 case Instruction::FPToSI:
751 case Instruction::PtrToInt:
752 case Instruction::IntToPtr:
753 case Instruction::BitCast: {
754 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
757 case Instruction::Add:
758 case Instruction::FAdd:
759 case Instruction::Sub:
760 case Instruction::FSub:
761 case Instruction::Mul:
762 case Instruction::FMul:
763 case Instruction::UDiv:
764 case Instruction::SDiv:
765 case Instruction::URem:
766 case Instruction::SRem:
767 case Instruction::And:
768 case Instruction::Or:
769 case Instruction::Xor: {
770 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
771 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
775 cerr << "ConstantExpr not handled: " << *CE << "\n";
781 if (C->getType()->getTypeID() == Type::PointerTyID)
782 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
783 if (GVSet.insert(GV))
784 Size = addSizeOfGlobal(GV, Size);
789 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
790 /// but are referenced from the given initializer.
792 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
794 if (!isa<UndefValue>(Init) &&
795 !isa<ConstantVector>(Init) &&
796 !isa<ConstantAggregateZero>(Init) &&
797 !isa<ConstantArray>(Init) &&
798 !isa<ConstantStruct>(Init) &&
799 Init->getType()->isFirstClassType())
800 Size = addSizeOfGlobalsInConstantVal(Init, Size);
804 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
805 /// globals; then walk the initializers of those globals looking for more.
806 /// If their size has not been considered yet, add it into the running total
809 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
813 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
815 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
817 const TargetInstrDesc &Desc = I->getDesc();
818 const MachineInstr &MI = *I;
819 unsigned NumOps = Desc.getNumOperands();
820 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
821 const MachineOperand &MO = MI.getOperand(CurOp);
823 GlobalValue* V = MO.getGlobal();
824 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
827 // If seen in previous function, it will have an entry here.
828 if (TheJIT->getPointerToGlobalIfAvailable(GV))
830 // If seen earlier in this function, it will have an entry here.
831 // FIXME: it should be possible to combine these tables, by
832 // assuming the addresses of the new globals in this module
833 // start at 0 (or something) and adjusting them after codegen
834 // complete. Another possibility is to grab a marker bit in GV.
835 if (GVSet.insert(GV))
836 // A variable as yet unseen. Add in its size.
837 Size = addSizeOfGlobal(GV, Size);
842 DOUT << "JIT: About to look through initializers\n";
843 // Look for more globals that are referenced only from initializers.
844 // GVSet.end is computed each time because the set can grow as we go.
845 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin();
846 I != GVSet.end(); I++) {
847 const GlobalVariable* GV = *I;
848 if (GV->hasInitializer())
849 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
855 void JITEmitter::startFunction(MachineFunction &F) {
856 DOUT << "JIT: Starting CodeGen of Function "
857 << F.getFunction()->getName() << "\n";
859 uintptr_t ActualSize = 0;
860 // Set the memory writable, if it's not already
861 MemMgr->setMemoryWritable();
862 if (MemMgr->NeedsExactSize()) {
863 DOUT << "JIT: ExactSize\n";
864 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
865 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
866 MachineConstantPool *MCP = F.getConstantPool();
868 // Ensure the constant pool/jump table info is at least 4-byte aligned.
869 ActualSize = RoundUpToAlign(ActualSize, 16);
871 // Add the alignment of the constant pool
872 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment());
874 // Add the constant pool size
875 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
877 // Add the aligment of the jump table info
878 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
880 // Add the jump table size
881 ActualSize += GetJumpTableSizeInBytes(MJTI);
883 // Add the alignment for the function
884 ActualSize = RoundUpToAlign(ActualSize,
885 std::max(F.getFunction()->getAlignment(), 8U));
887 // Add the function size
888 ActualSize += TII->GetFunctionSizeInBytes(F);
890 DOUT << "JIT: ActualSize before globals " << ActualSize << "\n";
891 // Add the size of the globals that will be allocated after this function.
892 // These are all the ones referenced from this function that were not
893 // previously allocated.
894 ActualSize += GetSizeOfGlobalsInBytes(F);
895 DOUT << "JIT: ActualSize after globals " << ActualSize << "\n";
898 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
900 BufferEnd = BufferBegin+ActualSize;
902 // Ensure the constant pool/jump table info is at least 4-byte aligned.
905 emitConstantPool(F.getConstantPool());
906 initJumpTableInfo(F.getJumpTableInfo());
908 // About to start emitting the machine code for the function.
909 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
910 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
912 MBBLocations.clear();
915 bool JITEmitter::finishFunction(MachineFunction &F) {
916 if (CurBufferPtr == BufferEnd) {
917 // FIXME: Allocate more space, then try again.
918 cerr << "JIT: Ran out of space for generated machine code!\n";
922 emitJumpTableInfo(F.getJumpTableInfo());
924 // FnStart is the start of the text, not the start of the constant pool and
925 // other per-function data.
927 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
929 // FnEnd is the end of the function's machine code.
930 uint8_t *FnEnd = CurBufferPtr;
932 if (!Relocations.empty()) {
933 CurFn = F.getFunction();
934 NumRelos += Relocations.size();
936 // Resolve the relocations to concrete pointers.
937 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
938 MachineRelocation &MR = Relocations[i];
940 if (!MR.letTargetResolve()) {
941 if (MR.isExternalSymbol()) {
942 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
944 DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
945 << ResultPtr << "]\n";
947 // If the target REALLY wants a stub for this function, emit it now.
948 if (!MR.doesntNeedStub()) {
949 if (!TheJIT->areDlsymStubsEnabled()) {
950 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
952 void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
954 Stub = Resolver.getExternalFunctionStub((void *)&Stub);
955 AddStubToCurrentFunction(Stub);
960 } else if (MR.isGlobalValue()) {
961 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
962 BufferBegin+MR.getMachineCodeOffset(),
963 MR.doesntNeedStub());
964 } else if (MR.isIndirectSymbol()) {
965 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
966 BufferBegin+MR.getMachineCodeOffset(),
967 MR.doesntNeedStub());
968 } else if (MR.isBasicBlock()) {
969 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
970 } else if (MR.isConstantPoolIndex()) {
971 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
973 assert(MR.isJumpTableIndex());
974 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
977 MR.setResultPointer(ResultPtr);
980 // if we are managing the GOT and the relocation wants an index,
982 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
983 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
985 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
986 DOUT << "JIT: GOT was out of date for " << ResultPtr
987 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
989 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
995 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
996 Relocations.size(), MemMgr->getGOTBase());
999 // Update the GOT entry for F to point to the new code.
1000 if (MemMgr->isManagingGOT()) {
1001 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
1002 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
1003 DOUT << "JIT: GOT was out of date for " << (void*)BufferBegin
1004 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
1005 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
1009 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
1010 // global variables that were referenced in the relocations.
1011 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
1013 if (CurBufferPtr == BufferEnd) {
1014 // FIXME: Allocate more space, then try again.
1015 cerr << "JIT: Ran out of space for generated machine code!\n";
1019 BufferBegin = CurBufferPtr = 0;
1020 NumBytes += FnEnd-FnStart;
1022 // Invalidate the icache if necessary.
1023 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
1025 JITEvent_EmittedFunctionDetails Details;
1026 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
1029 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
1030 << "] Function: " << F.getFunction()->getName()
1031 << ": " << (FnEnd-FnStart) << " bytes of text, "
1032 << Relocations.size() << " relocations\n";
1034 Relocations.clear();
1035 ConstPoolAddresses.clear();
1037 // Mark code region readable and executable if it's not so already.
1038 MemMgr->setMemoryExecutable();
1042 if (sys::hasDisassembler()) {
1043 DOUT << "JIT: Disassembled code:\n";
1044 DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
1046 DOUT << "JIT: Binary code:\n";
1048 uint8_t* q = FnStart;
1049 for (int i = 0; q < FnEnd; q += 4, ++i) {
1053 DOUT << "JIT: " << std::setw(8) << std::setfill('0')
1054 << (long)(q - FnStart) << ": ";
1056 for (int j = 3; j >= 0; --j) {
1060 DOUT << std::setw(2) << std::setfill('0') << (unsigned short)q[j];
1073 if (ExceptionHandling) {
1074 uintptr_t ActualSize = 0;
1075 SavedBufferBegin = BufferBegin;
1076 SavedBufferEnd = BufferEnd;
1077 SavedCurBufferPtr = CurBufferPtr;
1079 if (MemMgr->NeedsExactSize()) {
1080 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
1083 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
1085 BufferEnd = BufferBegin+ActualSize;
1086 uint8_t* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
1087 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
1089 BufferBegin = SavedBufferBegin;
1090 BufferEnd = SavedBufferEnd;
1091 CurBufferPtr = SavedCurBufferPtr;
1093 TheJIT->RegisterTable(FrameRegister);
1102 /// deallocateMemForFunction - Deallocate all memory for the specified
1103 /// function body. Also drop any references the function has to stubs.
1104 void JITEmitter::deallocateMemForFunction(Function *F) {
1105 MemMgr->deallocateMemForFunction(F);
1107 // If the function did not reference any stubs, return.
1108 if (CurFnStubUses.find(F) == CurFnStubUses.end())
1111 // For each referenced stub, erase the reference to this function, and then
1112 // erase the list of referenced stubs.
1113 SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
1114 for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
1115 void *Stub = StubList[i];
1117 // If we already invalidated this stub for this function, continue.
1118 if (StubFnRefs.count(Stub) == 0)
1121 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
1124 // If this function was the last reference to the stub, invalidate the stub
1125 // in the JITResolver. Were there a memory manager deallocateStub routine,
1126 // we could call that at this point too.
1127 if (FnRefs.empty()) {
1128 DOUT << "\nJIT: Invalidated Stub at [" << Stub << "]\n";
1129 StubFnRefs.erase(Stub);
1131 // Invalidate the stub. If it is a GV stub, update the JIT's global
1132 // mapping for that GV to zero, otherwise, search the string map of
1133 // external function names to stubs and remove the entry for this stub.
1134 GlobalValue *GV = Resolver.invalidateStub(Stub);
1136 TheJIT->updateGlobalMapping(GV, 0);
1138 for (StringMapIterator<void*> i = ExtFnStubs.begin(),
1139 e = ExtFnStubs.end(); i != e; ++i) {
1140 if (i->second == Stub) {
1141 ExtFnStubs.erase(i);
1148 CurFnStubUses.erase(F);
1152 void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1154 return JITCodeEmitter::allocateSpace(Size, Alignment);
1156 // create a new memory block if there is no active one.
1157 // care must be taken so that BufferBegin is invalidated when a
1159 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1160 BufferEnd = BufferBegin+Size;
1161 return CurBufferPtr;
1164 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1165 if (TheJIT->getJITInfo().hasCustomConstantPool())
1168 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1169 if (Constants.empty()) return;
1171 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
1172 unsigned Align = MCP->getConstantPoolAlignment();
1173 ConstantPoolBase = allocateSpace(Size, Align);
1176 if (ConstantPoolBase == 0) return; // Buffer overflow.
1178 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
1179 << "] (size: " << Size << ", alignment: " << Align << ")\n";
1181 // Initialize the memory for all of the constant pool entries.
1182 unsigned Offset = 0;
1183 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1184 MachineConstantPoolEntry CPE = Constants[i];
1185 unsigned AlignMask = CPE.getAlignment() - 1;
1186 Offset = (Offset + AlignMask) & ~AlignMask;
1188 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
1189 ConstPoolAddresses.push_back(CAddr);
1190 if (CPE.isMachineConstantPoolEntry()) {
1191 // FIXME: add support to lower machine constant pool values into bytes!
1192 cerr << "Initialize memory with machine specific constant pool entry"
1193 << " has not been implemented!\n";
1196 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
1197 DOUT << "JIT: CP" << i << " at [0x"
1198 << std::hex << CAddr << std::dec << "]\n";
1200 const Type *Ty = CPE.Val.ConstVal->getType();
1201 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty);
1205 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1206 if (TheJIT->getJITInfo().hasCustomJumpTables())
1209 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1210 if (JT.empty()) return;
1212 unsigned NumEntries = 0;
1213 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1214 NumEntries += JT[i].MBBs.size();
1216 unsigned EntrySize = MJTI->getEntrySize();
1218 // Just allocate space for all the jump tables now. We will fix up the actual
1219 // MBB entries in the tables after we emit the code for each block, since then
1220 // we will know the final locations of the MBBs in memory.
1222 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1225 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1226 if (TheJIT->getJITInfo().hasCustomJumpTables())
1229 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1230 if (JT.empty() || JumpTableBase == 0) return;
1232 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1233 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1234 // For each jump table, place the offset from the beginning of the table
1235 // to the target address.
1236 int *SlotPtr = (int*)JumpTableBase;
1238 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1239 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1240 // Store the offset of the basic block for this jump table slot in the
1241 // memory we allocated for the jump table in 'initJumpTableInfo'
1242 uintptr_t Base = (uintptr_t)SlotPtr;
1243 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1244 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1245 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1249 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1251 // For each jump table, map each target in the jump table to the address of
1252 // an emitted MachineBasicBlock.
1253 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1255 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1256 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1257 // Store the address of the basic block for this jump table slot in the
1258 // memory we allocated for the jump table in 'initJumpTableInfo'
1259 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1260 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1265 void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
1266 unsigned Alignment) {
1267 SavedBufferBegin = BufferBegin;
1268 SavedBufferEnd = BufferEnd;
1269 SavedCurBufferPtr = CurBufferPtr;
1271 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1272 BufferEnd = BufferBegin+StubSize+1;
1275 void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
1276 unsigned StubSize) {
1277 SavedBufferBegin = BufferBegin;
1278 SavedBufferEnd = BufferEnd;
1279 SavedCurBufferPtr = CurBufferPtr;
1281 BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
1282 BufferEnd = BufferBegin+StubSize+1;
1285 void *JITEmitter::finishGVStub(const GlobalValue* GV) {
1286 NumBytes += getCurrentPCOffset();
1287 std::swap(SavedBufferBegin, BufferBegin);
1288 BufferEnd = SavedBufferEnd;
1289 CurBufferPtr = SavedCurBufferPtr;
1290 return SavedBufferBegin;
1293 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1294 // in the constant pool that was last emitted with the 'emitConstantPool'
1297 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1298 assert(ConstantNum < ConstantPool->getConstants().size() &&
1299 "Invalid ConstantPoolIndex!");
1300 return ConstPoolAddresses[ConstantNum];
1303 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1304 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1306 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1307 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1308 assert(Index < JT.size() && "Invalid jump table index!");
1310 unsigned Offset = 0;
1311 unsigned EntrySize = JumpTable->getEntrySize();
1313 for (unsigned i = 0; i < Index; ++i)
1314 Offset += JT[i].MBBs.size();
1316 Offset *= EntrySize;
1318 return (uintptr_t)((char *)JumpTableBase + Offset);
1321 //===----------------------------------------------------------------------===//
1322 // Public interface to this file
1323 //===----------------------------------------------------------------------===//
1325 JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1326 return new JITEmitter(jit, JMM);
1329 // getPointerToNamedFunction - This function is used as a global wrapper to
1330 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1331 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1332 // need to resolve function(s) that are being mis-codegenerated, so we need to
1333 // resolve their addresses at runtime, and this is the way to do it.
1335 void *getPointerToNamedFunction(const char *Name) {
1336 if (Function *F = TheJIT->FindFunctionNamed(Name))
1337 return TheJIT->getPointerToFunction(F);
1338 return TheJIT->getPointerToNamedFunction(Name);
1342 // getPointerToFunctionOrStub - If the specified function has been
1343 // code-gen'd, return a pointer to the function. If not, compile it, or use
1344 // a stub to implement lazy compilation if available.
1346 void *JIT::getPointerToFunctionOrStub(Function *F) {
1347 // If we have already code generated the function, just return the address.
1348 if (void *Addr = getPointerToGlobalIfAvailable(F))
1351 // Get a stub if the target supports it.
1352 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1353 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1354 return JE->getJITResolver().getFunctionStub(F);
1357 void JIT::updateFunctionStub(Function *F) {
1358 // Get the empty stub we generated earlier.
1359 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1360 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1361 void *Stub = JE->getJITResolver().getFunctionStub(F);
1363 // Tell the target jit info to rewrite the stub at the specified address,
1364 // rather than creating a new one.
1365 void *Addr = getPointerToGlobalIfAvailable(F);
1366 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
1369 /// updateDlsymStubTable - Emit the data necessary to relocate the stubs
1370 /// that were emitted during code generation.
1372 void JIT::updateDlsymStubTable() {
1373 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1374 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1376 SmallVector<GlobalValue*, 8> GVs;
1377 SmallVector<void*, 8> Ptrs;
1378 const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
1380 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
1382 unsigned nStubs = GVs.size() + ExtFns.size();
1384 // If there are no relocatable stubs, return.
1388 // If there are no new relocatable stubs, return.
1389 void *CurTable = JE->getMemMgr()->getDlsymTable();
1390 if (CurTable && (*(unsigned *)CurTable == nStubs))
1393 // Calculate the size of the stub info
1394 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
1396 SmallVector<unsigned, 8> Offsets;
1397 for (unsigned i = 0; i != GVs.size(); ++i) {
1398 Offsets.push_back(offset);
1399 offset += GVs[i]->getName().length() + 1;
1401 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1403 Offsets.push_back(offset);
1404 offset += strlen(i->first()) + 1;
1407 // Allocate space for the new "stub", which contains the dlsym table.
1408 JE->startGVStub(0, offset, 4);
1410 // Emit the number of records
1411 JE->emitInt32(nStubs);
1413 // Emit the string offsets
1414 for (unsigned i = 0; i != nStubs; ++i)
1415 JE->emitInt32(Offsets[i]);
1417 // Emit the pointers. Verify that they are at least 2-byte aligned, and set
1418 // the low bit to 0 == GV, 1 == Function, so that the client code doing the
1419 // relocation can write the relocated pointer at the appropriate place in
1421 for (unsigned i = 0; i != GVs.size(); ++i) {
1422 intptr_t Ptr = (intptr_t)Ptrs[i];
1423 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
1425 if (isa<Function>(GVs[i]))
1428 if (sizeof(Ptr) == 8)
1433 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1435 intptr_t Ptr = (intptr_t)i->second | 1;
1437 if (sizeof(Ptr) == 8)
1443 // Emit the strings.
1444 for (unsigned i = 0; i != GVs.size(); ++i)
1445 JE->emitString(GVs[i]->getName());
1446 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1448 JE->emitString(i->first());
1450 // Tell the JIT memory manager where it is. The JIT Memory Manager will
1451 // deallocate space for the old one, if one existed.
1452 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
1455 /// freeMachineCodeForFunction - release machine code memory for given Function.
1457 void JIT::freeMachineCodeForFunction(Function *F) {
1459 // Delete translation for this from the ExecutionEngine, so it will get
1460 // retranslated next time it is used.
1461 void *OldPtr = updateGlobalMapping(F, 0);
1464 TheJIT->NotifyFreeingMachineCode(*F, OldPtr);
1466 // Free the actual memory for the function body and related stuff.
1467 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1468 cast<JITEmitter>(JCE)->deallocateMemForFunction(F);