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 //===----------------------------------------------------------------------===//
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/SmallPtrSet.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/CodeGen/JITCodeEmitter.h"
21 #include "llvm/CodeGen/MachineCodeInfo.h"
22 #include "llvm/CodeGen/MachineConstantPool.h"
23 #include "llvm/CodeGen/MachineFunction.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/IR/Constants.h"
31 #include "llvm/IR/DataLayout.h"
32 #include "llvm/IR/DebugInfo.h"
33 #include "llvm/IR/DerivedTypes.h"
34 #include "llvm/IR/Module.h"
35 #include "llvm/IR/Operator.h"
36 #include "llvm/IR/ValueHandle.h"
37 #include "llvm/IR/ValueMap.h"
38 #include "llvm/Support/Debug.h"
39 #include "llvm/Support/Disassembler.h"
40 #include "llvm/Support/ErrorHandling.h"
41 #include "llvm/Support/ManagedStatic.h"
42 #include "llvm/Support/Memory.h"
43 #include "llvm/Support/MutexGuard.h"
44 #include "llvm/Support/raw_ostream.h"
45 #include "llvm/Target/TargetInstrInfo.h"
46 #include "llvm/Target/TargetJITInfo.h"
47 #include "llvm/Target/TargetMachine.h"
48 #include "llvm/Target/TargetOptions.h"
55 #define DEBUG_TYPE "jit"
57 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
58 STATISTIC(NumRelos, "Number of relocations applied");
59 STATISTIC(NumRetries, "Number of retries with more memory");
62 // A declaration may stop being a declaration once it's fully read from bitcode.
63 // This function returns true if F is fully read and is still a declaration.
64 static bool isNonGhostDeclaration(const Function *F) {
65 return F->isDeclaration() && !F->isMaterializable();
68 //===----------------------------------------------------------------------===//
69 // JIT lazy compilation code.
73 class JITResolverState;
75 template<typename ValueTy>
76 struct NoRAUWValueMapConfig : public ValueMapConfig<ValueTy> {
77 typedef JITResolverState *ExtraData;
78 static void onRAUW(JITResolverState *, Value *Old, Value *New) {
79 llvm_unreachable("The JIT doesn't know how to handle a"
80 " RAUW on a value it has emitted.");
84 struct CallSiteValueMapConfig : public NoRAUWValueMapConfig<Function*> {
85 typedef JITResolverState *ExtraData;
86 static void onDelete(JITResolverState *JRS, Function *F);
89 class JITResolverState {
91 typedef ValueMap<Function*, void*, NoRAUWValueMapConfig<Function*> >
92 FunctionToLazyStubMapTy;
93 typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy;
94 typedef ValueMap<Function *, SmallPtrSet<void*, 1>,
95 CallSiteValueMapConfig> FunctionToCallSitesMapTy;
96 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
98 /// FunctionToLazyStubMap - Keep track of the lazy stub created for a
99 /// particular function so that we can reuse them if necessary.
100 FunctionToLazyStubMapTy FunctionToLazyStubMap;
102 /// CallSiteToFunctionMap - Keep track of the function that each lazy call
103 /// site corresponds to, and vice versa.
104 CallSiteToFunctionMapTy CallSiteToFunctionMap;
105 FunctionToCallSitesMapTy FunctionToCallSitesMap;
107 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
108 /// particular GlobalVariable so that we can reuse them if necessary.
109 GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
112 /// Instance of the JIT this ResolverState serves.
117 JITResolverState(JIT *jit) : FunctionToLazyStubMap(this),
118 FunctionToCallSitesMap(this) {
124 FunctionToLazyStubMapTy& getFunctionToLazyStubMap(
125 const MutexGuard& locked) {
126 assert(locked.holds(TheJIT->lock));
127 return FunctionToLazyStubMap;
130 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& lck) {
131 assert(lck.holds(TheJIT->lock));
132 return GlobalToIndirectSymMap;
135 std::pair<void *, Function *> LookupFunctionFromCallSite(
136 const MutexGuard &locked, void *CallSite) const {
137 assert(locked.holds(TheJIT->lock));
139 // The address given to us for the stub may not be exactly right, it
140 // might be a little bit after the stub. As such, use upper_bound to
142 CallSiteToFunctionMapTy::const_iterator I =
143 CallSiteToFunctionMap.upper_bound(CallSite);
144 assert(I != CallSiteToFunctionMap.begin() &&
145 "This is not a known call site!");
150 void AddCallSite(const MutexGuard &locked, void *CallSite, Function *F) {
151 assert(locked.holds(TheJIT->lock));
153 bool Inserted = CallSiteToFunctionMap.insert(
154 std::make_pair(CallSite, F)).second;
156 assert(Inserted && "Pair was already in CallSiteToFunctionMap");
157 FunctionToCallSitesMap[F].insert(CallSite);
160 void EraseAllCallSitesForPrelocked(Function *F);
162 // Erases _all_ call sites regardless of their function. This is used to
163 // unregister the stub addresses from the StubToResolverMap in
165 void EraseAllCallSitesPrelocked();
168 /// JITResolver - Keep track of, and resolve, call sites for functions that
169 /// have not yet been compiled.
171 typedef JITResolverState::FunctionToLazyStubMapTy FunctionToLazyStubMapTy;
172 typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy;
173 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
175 /// LazyResolverFn - The target lazy resolver function that we actually
176 /// rewrite instructions to use.
177 TargetJITInfo::LazyResolverFn LazyResolverFn;
179 JITResolverState state;
181 /// ExternalFnToStubMap - This is the equivalent of FunctionToLazyStubMap
182 /// for external functions. TODO: Of course, external functions don't need
183 /// a lazy stub. It's actually here to make it more likely that far calls
184 /// succeed, but no single stub can guarantee that. I'll remove this in a
185 /// subsequent checkin when I actually fix far calls.
186 std::map<void*, void*> ExternalFnToStubMap;
188 /// revGOTMap - map addresses to indexes in the GOT
189 std::map<void*, unsigned> revGOTMap;
190 unsigned nextGOTIndex;
194 /// Instance of JIT corresponding to this Resolver.
198 explicit JITResolver(JIT &jit, JITEmitter &je)
199 : state(&jit), nextGOTIndex(0), JE(je), TheJIT(&jit) {
200 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
205 /// getLazyFunctionStubIfAvailable - This returns a pointer to a function's
206 /// lazy-compilation stub if it has already been created.
207 void *getLazyFunctionStubIfAvailable(Function *F);
209 /// getLazyFunctionStub - This returns a pointer to a function's
210 /// lazy-compilation stub, creating one on demand as needed.
211 void *getLazyFunctionStub(Function *F);
213 /// getExternalFunctionStub - Return a stub for the function at the
214 /// specified address, created lazily on demand.
215 void *getExternalFunctionStub(void *FnAddr);
217 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
218 /// specified GV address.
219 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
221 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
222 /// an address. This function only manages slots, it does not manage the
223 /// contents of the slots or the memory associated with the GOT.
224 unsigned getGOTIndexForAddr(void *addr);
226 /// JITCompilerFn - This function is called to resolve a stub to a compiled
227 /// address. If the LLVM Function corresponding to the stub has not yet
228 /// been compiled, this function compiles it first.
229 static void *JITCompilerFn(void *Stub);
232 class StubToResolverMapTy {
233 /// Map a stub address to a specific instance of a JITResolver so that
234 /// lazily-compiled functions can find the right resolver to use.
237 std::map<void*, JITResolver*> Map;
239 /// Guards Map from concurrent accesses.
240 mutable sys::Mutex Lock;
243 /// Registers a Stub to be resolved by Resolver.
244 void RegisterStubResolver(void *Stub, JITResolver *Resolver) {
245 MutexGuard guard(Lock);
246 Map.insert(std::make_pair(Stub, Resolver));
248 /// Unregisters the Stub when it's invalidated.
249 void UnregisterStubResolver(void *Stub) {
250 MutexGuard guard(Lock);
253 /// Returns the JITResolver instance that owns the Stub.
254 JITResolver *getResolverFromStub(void *Stub) const {
255 MutexGuard guard(Lock);
256 // The address given to us for the stub may not be exactly right, it might
257 // be a little bit after the stub. As such, use upper_bound to find it.
258 // This is the same trick as in LookupFunctionFromCallSite from
260 std::map<void*, JITResolver*>::const_iterator I = Map.upper_bound(Stub);
261 assert(I != Map.begin() && "This is not a known stub!");
265 /// True if any stubs refer to the given resolver. Only used in an assert().
267 bool ResolverHasStubs(JITResolver* Resolver) const {
268 MutexGuard guard(Lock);
269 for (std::map<void*, JITResolver*>::const_iterator I = Map.begin(),
270 E = Map.end(); I != E; ++I) {
271 if (I->second == Resolver)
277 /// This needs to be static so that a lazy call stub can access it with no
278 /// context except the address of the stub.
279 ManagedStatic<StubToResolverMapTy> StubToResolverMap;
281 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
282 /// used to output functions to memory for execution.
283 class JITEmitter : public JITCodeEmitter {
284 JITMemoryManager *MemMgr;
286 // When outputting a function stub in the context of some other function, we
287 // save BufferBegin/BufferEnd/CurBufferPtr here.
288 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
290 // When reattempting to JIT a function after running out of space, we store
291 // the estimated size of the function we're trying to JIT here, so we can
292 // ask the memory manager for at least this much space. When we
293 // successfully emit the function, we reset this back to zero.
294 uintptr_t SizeEstimate;
296 /// Relocations - These are the relocations that the function needs, as
298 std::vector<MachineRelocation> Relocations;
300 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
301 /// It is filled in by the StartMachineBasicBlock callback and queried by
302 /// the getMachineBasicBlockAddress callback.
303 std::vector<uintptr_t> MBBLocations;
305 /// ConstantPool - The constant pool for the current function.
307 MachineConstantPool *ConstantPool;
309 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
311 void *ConstantPoolBase;
313 /// ConstPoolAddresses - Addresses of individual constant pool entries.
315 SmallVector<uintptr_t, 8> ConstPoolAddresses;
317 /// JumpTable - The jump tables for the current function.
319 MachineJumpTableInfo *JumpTable;
321 /// JumpTableBase - A pointer to the first entry in the jump table.
325 /// Resolver - This contains info about the currently resolved functions.
326 JITResolver Resolver;
328 /// LabelLocations - This vector is a mapping from Label ID's to their
330 DenseMap<MCSymbol*, uintptr_t> LabelLocations;
332 /// MMI - Machine module info for exception informations
333 MachineModuleInfo* MMI;
335 // CurFn - The llvm function being emitted. Only valid during
337 const Function *CurFn;
339 /// Information about emitted code, which is passed to the
340 /// JITEventListeners. This is reset in startFunction and used in
342 JITEvent_EmittedFunctionDetails EmissionDetails;
345 void *FunctionBody; // Beginning of the function's allocation.
346 void *Code; // The address the function's code actually starts at.
347 void *ExceptionTable;
348 EmittedCode() : FunctionBody(nullptr), Code(nullptr),
349 ExceptionTable(nullptr) {}
351 struct EmittedFunctionConfig : public ValueMapConfig<const Function*> {
352 typedef JITEmitter *ExtraData;
353 static void onDelete(JITEmitter *, const Function*);
354 static void onRAUW(JITEmitter *, const Function*, const Function*);
356 ValueMap<const Function *, EmittedCode,
357 EmittedFunctionConfig> EmittedFunctions;
361 /// Instance of the JIT
365 JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM)
366 : SizeEstimate(0), Resolver(jit, *this), MMI(nullptr), CurFn(nullptr),
367 EmittedFunctions(this), TheJIT(&jit) {
368 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
369 if (jit.getJITInfo().needsGOT()) {
370 MemMgr->AllocateGOT();
371 DEBUG(dbgs() << "JIT is managing a GOT\n");
379 JITResolver &getJITResolver() { return Resolver; }
381 void startFunction(MachineFunction &F) override;
382 bool finishFunction(MachineFunction &F) override;
384 void emitConstantPool(MachineConstantPool *MCP);
385 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
386 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
388 void startGVStub(const GlobalValue* GV,
389 unsigned StubSize, unsigned Alignment = 1);
390 void startGVStub(void *Buffer, unsigned StubSize);
392 void *allocIndirectGV(const GlobalValue *GV, const uint8_t *Buffer,
393 size_t Size, unsigned Alignment) override;
395 /// allocateSpace - Reserves space in the current block if any, or
396 /// allocate a new one of the given size.
397 void *allocateSpace(uintptr_t Size, unsigned Alignment) override;
399 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace,
400 /// this method does not allocate memory in the current output buffer,
401 /// because a global may live longer than the current function.
402 void *allocateGlobal(uintptr_t Size, unsigned Alignment) override;
404 void addRelocation(const MachineRelocation &MR) override {
405 Relocations.push_back(MR);
408 void StartMachineBasicBlock(MachineBasicBlock *MBB) override {
409 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
410 MBBLocations.resize((MBB->getNumber()+1)*2);
411 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
412 if (MBB->hasAddressTaken())
413 TheJIT->addPointerToBasicBlock(MBB->getBasicBlock(),
414 (void*)getCurrentPCValue());
415 DEBUG(dbgs() << "JIT: Emitting BB" << MBB->getNumber() << " at ["
416 << (void*) getCurrentPCValue() << "]\n");
419 uintptr_t getConstantPoolEntryAddress(unsigned Entry) const override;
420 uintptr_t getJumpTableEntryAddress(unsigned Entry) const override;
423 getMachineBasicBlockAddress(MachineBasicBlock *MBB) const override {
424 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
425 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
426 return MBBLocations[MBB->getNumber()];
429 /// retryWithMoreMemory - Log a retry and deallocate all memory for the
430 /// given function. Increase the minimum allocation size so that we get
431 /// more memory next time.
432 void retryWithMoreMemory(MachineFunction &F);
434 /// deallocateMemForFunction - Deallocate all memory for the specified
436 void deallocateMemForFunction(const Function *F);
438 void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) override;
440 void emitLabel(MCSymbol *Label) override {
441 LabelLocations[Label] = getCurrentPCValue();
444 DenseMap<MCSymbol*, uintptr_t> *getLabelLocations() override {
445 return &LabelLocations;
448 uintptr_t getLabelAddress(MCSymbol *Label) const override {
449 assert(LabelLocations.count(Label) && "Label not emitted!");
450 return LabelLocations.find(Label)->second;
453 void setModuleInfo(MachineModuleInfo* Info) override {
458 void *getPointerToGlobal(GlobalValue *GV, void *Reference,
459 bool MayNeedFarStub);
460 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference);
464 void CallSiteValueMapConfig::onDelete(JITResolverState *JRS, Function *F) {
465 JRS->EraseAllCallSitesForPrelocked(F);
468 void JITResolverState::EraseAllCallSitesForPrelocked(Function *F) {
469 FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F);
470 if (F2C == FunctionToCallSitesMap.end())
472 StubToResolverMapTy &S2RMap = *StubToResolverMap;
473 for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(),
474 E = F2C->second.end(); I != E; ++I) {
475 S2RMap.UnregisterStubResolver(*I);
476 bool Erased = CallSiteToFunctionMap.erase(*I);
478 assert(Erased && "Missing call site->function mapping");
480 FunctionToCallSitesMap.erase(F2C);
483 void JITResolverState::EraseAllCallSitesPrelocked() {
484 StubToResolverMapTy &S2RMap = *StubToResolverMap;
485 for (CallSiteToFunctionMapTy::const_iterator
486 I = CallSiteToFunctionMap.begin(),
487 E = CallSiteToFunctionMap.end(); I != E; ++I) {
488 S2RMap.UnregisterStubResolver(I->first);
490 CallSiteToFunctionMap.clear();
491 FunctionToCallSitesMap.clear();
494 JITResolver::~JITResolver() {
495 // No need to lock because we're in the destructor, and state isn't shared.
496 state.EraseAllCallSitesPrelocked();
497 assert(!StubToResolverMap->ResolverHasStubs(this) &&
498 "Resolver destroyed with stubs still alive.");
501 /// getLazyFunctionStubIfAvailable - This returns a pointer to a function stub
502 /// if it has already been created.
503 void *JITResolver::getLazyFunctionStubIfAvailable(Function *F) {
504 MutexGuard locked(TheJIT->lock);
506 // If we already have a stub for this function, recycle it.
507 return state.getFunctionToLazyStubMap(locked).lookup(F);
510 /// getFunctionStub - This returns a pointer to a function stub, creating
511 /// one on demand as needed.
512 void *JITResolver::getLazyFunctionStub(Function *F) {
513 MutexGuard locked(TheJIT->lock);
515 // If we already have a lazy stub for this function, recycle it.
516 void *&Stub = state.getFunctionToLazyStubMap(locked)[F];
517 if (Stub) return Stub;
519 // Call the lazy resolver function if we are JIT'ing lazily. Otherwise we
520 // must resolve the symbol now.
521 void *Actual = TheJIT->isCompilingLazily()
522 ? (void *)(intptr_t)LazyResolverFn : (void *)nullptr;
524 // If this is an external declaration, attempt to resolve the address now
525 // to place in the stub.
526 if (isNonGhostDeclaration(F) || F->hasAvailableExternallyLinkage()) {
527 Actual = TheJIT->getPointerToFunction(F);
529 // If we resolved the symbol to a null address (eg. a weak external)
530 // don't emit a stub. Return a null pointer to the application.
531 if (!Actual) return nullptr;
534 TargetJITInfo::StubLayout SL = TheJIT->getJITInfo().getStubLayout();
535 JE.startGVStub(F, SL.Size, SL.Alignment);
536 // Codegen a new stub, calling the lazy resolver or the actual address of the
537 // external function, if it was resolved.
538 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual, JE);
541 if (Actual != (void*)(intptr_t)LazyResolverFn) {
542 // If we are getting the stub for an external function, we really want the
543 // address of the stub in the GlobalAddressMap for the JIT, not the address
544 // of the external function.
545 TheJIT->updateGlobalMapping(F, Stub);
548 DEBUG(dbgs() << "JIT: Lazy stub emitted at [" << Stub << "] for function '"
549 << F->getName() << "'\n");
551 if (TheJIT->isCompilingLazily()) {
552 // Register this JITResolver as the one corresponding to this call site so
553 // JITCompilerFn will be able to find it.
554 StubToResolverMap->RegisterStubResolver(Stub, this);
556 // Finally, keep track of the stub-to-Function mapping so that the
557 // JITCompilerFn knows which function to compile!
558 state.AddCallSite(locked, Stub, F);
559 } else if (!Actual) {
560 // If we are JIT'ing non-lazily but need to call a function that does not
561 // exist yet, add it to the JIT's work list so that we can fill in the
562 // stub address later.
563 assert(!isNonGhostDeclaration(F) && !F->hasAvailableExternallyLinkage() &&
564 "'Actual' should have been set above.");
565 TheJIT->addPendingFunction(F);
571 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
573 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
574 MutexGuard locked(TheJIT->lock);
576 // If we already have a stub for this global variable, recycle it.
577 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
578 if (IndirectSym) return IndirectSym;
580 // Otherwise, codegen a new indirect symbol.
581 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
584 DEBUG(dbgs() << "JIT: Indirect symbol emitted at [" << IndirectSym
585 << "] for GV '" << GV->getName() << "'\n");
590 /// getExternalFunctionStub - Return a stub for the function at the
591 /// specified address, created lazily on demand.
592 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
593 // If we already have a stub for this function, recycle it.
594 void *&Stub = ExternalFnToStubMap[FnAddr];
595 if (Stub) return Stub;
597 TargetJITInfo::StubLayout SL = TheJIT->getJITInfo().getStubLayout();
598 JE.startGVStub(nullptr, SL.Size, SL.Alignment);
599 Stub = TheJIT->getJITInfo().emitFunctionStub(nullptr, FnAddr, JE);
602 DEBUG(dbgs() << "JIT: Stub emitted at [" << Stub
603 << "] for external function at '" << FnAddr << "'\n");
607 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
608 unsigned idx = revGOTMap[addr];
610 idx = ++nextGOTIndex;
611 revGOTMap[addr] = idx;
612 DEBUG(dbgs() << "JIT: Adding GOT entry " << idx << " for addr ["
618 /// JITCompilerFn - This function is called when a lazy compilation stub has
619 /// been entered. It looks up which function this stub corresponds to, compiles
620 /// it if necessary, then returns the resultant function pointer.
621 void *JITResolver::JITCompilerFn(void *Stub) {
622 JITResolver *JR = StubToResolverMap->getResolverFromStub(Stub);
623 assert(JR && "Unable to find the corresponding JITResolver to the call site");
625 Function* F = nullptr;
626 void* ActualPtr = nullptr;
629 // Only lock for getting the Function. The call getPointerToFunction made
630 // in this function might trigger function materializing, which requires
631 // JIT lock to be unlocked.
632 MutexGuard locked(JR->TheJIT->lock);
634 // The address given to us for the stub may not be exactly right, it might
635 // be a little bit after the stub. As such, use upper_bound to find it.
636 std::pair<void*, Function*> I =
637 JR->state.LookupFunctionFromCallSite(locked, Stub);
642 // If we have already code generated the function, just return the address.
643 void *Result = JR->TheJIT->getPointerToGlobalIfAvailable(F);
646 // Otherwise we don't have it, do lazy compilation now.
648 // If lazy compilation is disabled, emit a useful error message and abort.
649 if (!JR->TheJIT->isCompilingLazily()) {
650 report_fatal_error("LLVM JIT requested to do lazy compilation of"
652 + F->getName() + "' when lazy compiles are disabled!");
655 DEBUG(dbgs() << "JIT: Lazily resolving function '" << F->getName()
656 << "' In stub ptr = " << Stub << " actual ptr = "
657 << ActualPtr << "\n");
660 Result = JR->TheJIT->getPointerToFunction(F);
663 // Reacquire the lock to update the GOT map.
664 MutexGuard locked(JR->TheJIT->lock);
666 // We might like to remove the call site from the CallSiteToFunction map, but
667 // we can't do that! Multiple threads could be stuck, waiting to acquire the
668 // lock above. As soon as the 1st function finishes compiling the function,
669 // the next one will be released, and needs to be able to find the function it
672 // FIXME: We could rewrite all references to this stub if we knew them.
674 // What we will do is set the compiled function address to map to the
675 // same GOT entry as the stub so that later clients may update the GOT
676 // if they see it still using the stub address.
677 // Note: this is done so the Resolver doesn't have to manage GOT memory
678 // Do this without allocating map space if the target isn't using a GOT
679 if(JR->revGOTMap.find(Stub) != JR->revGOTMap.end())
680 JR->revGOTMap[Result] = JR->revGOTMap[Stub];
685 //===----------------------------------------------------------------------===//
689 static GlobalObject *getSimpleAliasee(Constant *C) {
690 C = C->stripPointerCasts();
691 return dyn_cast<GlobalObject>(C);
694 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
695 bool MayNeedFarStub) {
696 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
697 return TheJIT->getOrEmitGlobalVariable(GV);
699 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
700 // We can only handle simple cases.
701 if (GlobalValue *GV = getSimpleAliasee(GA->getAliasee()))
702 return TheJIT->getPointerToGlobal(GV);
706 // If we have already compiled the function, return a pointer to its body.
707 Function *F = cast<Function>(V);
709 void *FnStub = Resolver.getLazyFunctionStubIfAvailable(F);
711 // Return the function stub if it's already created. We do this first so
712 // that we're returning the same address for the function as any previous
713 // call. TODO: Yes, this is wrong. The lazy stub isn't guaranteed to be
714 // close enough to call.
718 // If we know the target can handle arbitrary-distance calls, try to
719 // return a direct pointer.
720 if (!MayNeedFarStub) {
721 // If we have code, go ahead and return that.
722 void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
723 if (ResultPtr) return ResultPtr;
725 // If this is an external function pointer, we can force the JIT to
726 // 'compile' it, which really just adds it to the map.
727 if (isNonGhostDeclaration(F) || F->hasAvailableExternallyLinkage())
728 return TheJIT->getPointerToFunction(F);
731 // Otherwise, we may need a to emit a stub, and, conservatively, we always do
732 // so. Note that it's possible to return null from getLazyFunctionStub in the
733 // case of a weak extern that fails to resolve.
734 return Resolver.getLazyFunctionStub(F);
737 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference) {
738 // Make sure GV is emitted first, and create a stub containing the fully
740 void *GVAddress = getPointerToGlobal(V, Reference, false);
741 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
745 void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
746 if (DL.isUnknown()) return;
747 if (!BeforePrintingInsn) return;
749 const LLVMContext &Context = EmissionDetails.MF->getFunction()->getContext();
751 if (DL.getScope(Context) != nullptr && PrevDL != DL) {
752 JITEvent_EmittedFunctionDetails::LineStart NextLine;
753 NextLine.Address = getCurrentPCValue();
755 EmissionDetails.LineStarts.push_back(NextLine);
761 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
762 const DataLayout *TD) {
763 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
764 if (Constants.empty()) return 0;
767 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
768 MachineConstantPoolEntry CPE = Constants[i];
769 unsigned AlignMask = CPE.getAlignment() - 1;
770 Size = (Size + AlignMask) & ~AlignMask;
771 Type *Ty = CPE.getType();
772 Size += TD->getTypeAllocSize(Ty);
777 void JITEmitter::startFunction(MachineFunction &F) {
778 DEBUG(dbgs() << "JIT: Starting CodeGen of Function "
779 << F.getName() << "\n");
781 uintptr_t ActualSize = 0;
782 // Set the memory writable, if it's not already
783 MemMgr->setMemoryWritable();
785 if (SizeEstimate > 0) {
786 // SizeEstimate will be non-zero on reallocation attempts.
787 ActualSize = SizeEstimate;
790 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
792 BufferEnd = BufferBegin+ActualSize;
793 EmittedFunctions[F.getFunction()].FunctionBody = BufferBegin;
795 // Ensure the constant pool/jump table info is at least 4-byte aligned.
798 emitConstantPool(F.getConstantPool());
799 if (MachineJumpTableInfo *MJTI = F.getJumpTableInfo())
800 initJumpTableInfo(MJTI);
802 // About to start emitting the machine code for the function.
803 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
804 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
805 EmittedFunctions[F.getFunction()].Code = CurBufferPtr;
807 MBBLocations.clear();
809 EmissionDetails.MF = &F;
810 EmissionDetails.LineStarts.clear();
813 bool JITEmitter::finishFunction(MachineFunction &F) {
814 if (CurBufferPtr == BufferEnd) {
815 // We must call endFunctionBody before retrying, because
816 // deallocateMemForFunction requires it.
817 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
818 retryWithMoreMemory(F);
822 if (MachineJumpTableInfo *MJTI = F.getJumpTableInfo())
823 emitJumpTableInfo(MJTI);
825 // FnStart is the start of the text, not the start of the constant pool and
826 // other per-function data.
828 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
830 // FnEnd is the end of the function's machine code.
831 uint8_t *FnEnd = CurBufferPtr;
833 if (!Relocations.empty()) {
834 CurFn = F.getFunction();
835 NumRelos += Relocations.size();
837 // Resolve the relocations to concrete pointers.
838 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
839 MachineRelocation &MR = Relocations[i];
840 void *ResultPtr = nullptr;
841 if (!MR.letTargetResolve()) {
842 if (MR.isExternalSymbol()) {
843 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
845 DEBUG(dbgs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
846 << ResultPtr << "]\n");
848 // If the target REALLY wants a stub for this function, emit it now.
849 if (MR.mayNeedFarStub()) {
850 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
852 } else if (MR.isGlobalValue()) {
853 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
854 BufferBegin+MR.getMachineCodeOffset(),
855 MR.mayNeedFarStub());
856 } else if (MR.isIndirectSymbol()) {
857 ResultPtr = getPointerToGVIndirectSym(
858 MR.getGlobalValue(), BufferBegin+MR.getMachineCodeOffset());
859 } else if (MR.isBasicBlock()) {
860 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
861 } else if (MR.isConstantPoolIndex()) {
863 (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
865 assert(MR.isJumpTableIndex());
866 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
869 MR.setResultPointer(ResultPtr);
872 // if we are managing the GOT and the relocation wants an index,
874 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
875 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
877 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
878 DEBUG(dbgs() << "JIT: GOT was out of date for " << ResultPtr
879 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
881 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
887 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
888 Relocations.size(), MemMgr->getGOTBase());
891 // Update the GOT entry for F to point to the new code.
892 if (MemMgr->isManagingGOT()) {
893 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
894 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
895 DEBUG(dbgs() << "JIT: GOT was out of date for " << (void*)BufferBegin
896 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
898 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
902 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
903 // global variables that were referenced in the relocations.
904 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
906 if (CurBufferPtr == BufferEnd) {
907 retryWithMoreMemory(F);
910 // Now that we've succeeded in emitting the function, reset the
911 // SizeEstimate back down to zero.
915 BufferBegin = CurBufferPtr = nullptr;
916 NumBytes += FnEnd-FnStart;
918 // Invalidate the icache if necessary.
919 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
921 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
924 // Reset the previous debug location.
927 DEBUG(dbgs() << "JIT: Finished CodeGen of [" << (void*)FnStart
928 << "] Function: " << F.getName()
929 << ": " << (FnEnd-FnStart) << " bytes of text, "
930 << Relocations.size() << " relocations\n");
933 ConstPoolAddresses.clear();
935 // Mark code region readable and executable if it's not so already.
936 MemMgr->setMemoryExecutable();
939 if (sys::hasDisassembler()) {
940 dbgs() << "JIT: Disassembled code:\n";
941 dbgs() << sys::disassembleBuffer(FnStart, FnEnd-FnStart,
944 dbgs() << "JIT: Binary code:\n";
945 uint8_t* q = FnStart;
946 for (int i = 0; q < FnEnd; q += 4, ++i) {
950 dbgs() << "JIT: " << (long)(q - FnStart) << ": ";
952 for (int j = 3; j >= 0; --j) {
956 dbgs() << (unsigned short)q[j];
974 void JITEmitter::retryWithMoreMemory(MachineFunction &F) {
975 DEBUG(dbgs() << "JIT: Ran out of space for native code. Reattempting.\n");
976 Relocations.clear(); // Clear the old relocations or we'll reapply them.
977 ConstPoolAddresses.clear();
979 deallocateMemForFunction(F.getFunction());
980 // Try again with at least twice as much free space.
981 SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin));
983 for (MachineFunction::iterator MBB = F.begin(), E = F.end(); MBB != E; ++MBB){
984 if (MBB->hasAddressTaken())
985 TheJIT->clearPointerToBasicBlock(MBB->getBasicBlock());
989 /// deallocateMemForFunction - Deallocate all memory for the specified
990 /// function body. Also drop any references the function has to stubs.
991 /// May be called while the Function is being destroyed inside ~Value().
992 void JITEmitter::deallocateMemForFunction(const Function *F) {
993 ValueMap<const Function *, EmittedCode, EmittedFunctionConfig>::iterator
994 Emitted = EmittedFunctions.find(F);
995 if (Emitted != EmittedFunctions.end()) {
996 MemMgr->deallocateFunctionBody(Emitted->second.FunctionBody);
997 TheJIT->NotifyFreeingMachineCode(Emitted->second.Code);
999 EmittedFunctions.erase(Emitted);
1004 void *JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1006 return JITCodeEmitter::allocateSpace(Size, Alignment);
1008 // create a new memory block if there is no active one.
1009 // care must be taken so that BufferBegin is invalidated when a
1011 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1012 BufferEnd = BufferBegin+Size;
1013 return CurBufferPtr;
1016 void *JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
1017 // Delegate this call through the memory manager.
1018 return MemMgr->allocateGlobal(Size, Alignment);
1021 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1022 if (TheJIT->getJITInfo().hasCustomConstantPool())
1025 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1026 if (Constants.empty()) return;
1028 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getDataLayout());
1029 unsigned Align = MCP->getConstantPoolAlignment();
1030 ConstantPoolBase = allocateSpace(Size, Align);
1033 if (!ConstantPoolBase) return; // Buffer overflow.
1035 DEBUG(dbgs() << "JIT: Emitted constant pool at [" << ConstantPoolBase
1036 << "] (size: " << Size << ", alignment: " << Align << ")\n");
1038 // Initialize the memory for all of the constant pool entries.
1039 unsigned Offset = 0;
1040 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1041 MachineConstantPoolEntry CPE = Constants[i];
1042 unsigned AlignMask = CPE.getAlignment() - 1;
1043 Offset = (Offset + AlignMask) & ~AlignMask;
1045 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
1046 ConstPoolAddresses.push_back(CAddr);
1047 if (CPE.isMachineConstantPoolEntry()) {
1048 // FIXME: add support to lower machine constant pool values into bytes!
1049 report_fatal_error("Initialize memory with machine specific constant pool"
1050 "entry has not been implemented!");
1052 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
1053 DEBUG(dbgs() << "JIT: CP" << i << " at [0x";
1054 dbgs().write_hex(CAddr) << "]\n");
1056 Type *Ty = CPE.Val.ConstVal->getType();
1057 Offset += TheJIT->getDataLayout()->getTypeAllocSize(Ty);
1061 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1062 if (TheJIT->getJITInfo().hasCustomJumpTables())
1064 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline)
1067 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1068 if (JT.empty()) return;
1070 unsigned NumEntries = 0;
1071 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1072 NumEntries += JT[i].MBBs.size();
1074 unsigned EntrySize = MJTI->getEntrySize(*TheJIT->getDataLayout());
1076 // Just allocate space for all the jump tables now. We will fix up the actual
1077 // MBB entries in the tables after we emit the code for each block, since then
1078 // we will know the final locations of the MBBs in memory.
1080 JumpTableBase = allocateSpace(NumEntries * EntrySize,
1081 MJTI->getEntryAlignment(*TheJIT->getDataLayout()));
1084 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1085 if (TheJIT->getJITInfo().hasCustomJumpTables())
1088 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1089 if (JT.empty() || !JumpTableBase) return;
1092 switch (MJTI->getEntryKind()) {
1093 case MachineJumpTableInfo::EK_Inline:
1095 case MachineJumpTableInfo::EK_BlockAddress: {
1096 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1098 assert(MJTI->getEntrySize(*TheJIT->getDataLayout()) == sizeof(void*) &&
1101 // For each jump table, map each target in the jump table to the address of
1102 // an emitted MachineBasicBlock.
1103 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1105 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1106 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1107 // Store the address of the basic block for this jump table slot in the
1108 // memory we allocated for the jump table in 'initJumpTableInfo'
1109 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1110 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1115 case MachineJumpTableInfo::EK_Custom32:
1116 case MachineJumpTableInfo::EK_GPRel32BlockAddress:
1117 case MachineJumpTableInfo::EK_LabelDifference32: {
1118 assert(MJTI->getEntrySize(*TheJIT->getDataLayout()) == 4&&"Cross JIT'ing?");
1119 // For each jump table, place the offset from the beginning of the table
1120 // to the target address.
1121 int *SlotPtr = (int*)JumpTableBase;
1123 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1124 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1125 // Store the offset of the basic block for this jump table slot in the
1126 // memory we allocated for the jump table in 'initJumpTableInfo'
1127 uintptr_t Base = (uintptr_t)SlotPtr;
1128 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1129 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1130 /// FIXME: USe EntryKind instead of magic "getPICJumpTableEntry" hook.
1131 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1136 case MachineJumpTableInfo::EK_GPRel64BlockAddress:
1138 "JT Info emission not implemented for GPRel64BlockAddress yet.");
1142 void JITEmitter::startGVStub(const GlobalValue* GV,
1143 unsigned StubSize, unsigned Alignment) {
1144 SavedBufferBegin = BufferBegin;
1145 SavedBufferEnd = BufferEnd;
1146 SavedCurBufferPtr = CurBufferPtr;
1148 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1149 BufferEnd = BufferBegin+StubSize+1;
1152 void JITEmitter::startGVStub(void *Buffer, unsigned StubSize) {
1153 SavedBufferBegin = BufferBegin;
1154 SavedBufferEnd = BufferEnd;
1155 SavedCurBufferPtr = CurBufferPtr;
1157 BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
1158 BufferEnd = BufferBegin+StubSize+1;
1161 void JITEmitter::finishGVStub() {
1162 assert(CurBufferPtr != BufferEnd && "Stub overflowed allocated space.");
1163 NumBytes += getCurrentPCOffset();
1164 BufferBegin = SavedBufferBegin;
1165 BufferEnd = SavedBufferEnd;
1166 CurBufferPtr = SavedCurBufferPtr;
1169 void *JITEmitter::allocIndirectGV(const GlobalValue *GV,
1170 const uint8_t *Buffer, size_t Size,
1171 unsigned Alignment) {
1172 uint8_t *IndGV = MemMgr->allocateStub(GV, Size, Alignment);
1173 memcpy(IndGV, Buffer, Size);
1177 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1178 // in the constant pool that was last emitted with the 'emitConstantPool'
1181 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1182 assert(ConstantNum < ConstantPool->getConstants().size() &&
1183 "Invalid ConstantPoolIndex!");
1184 return ConstPoolAddresses[ConstantNum];
1187 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1188 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1190 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1191 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1192 assert(Index < JT.size() && "Invalid jump table index!");
1194 unsigned EntrySize = JumpTable->getEntrySize(*TheJIT->getDataLayout());
1196 unsigned Offset = 0;
1197 for (unsigned i = 0; i < Index; ++i)
1198 Offset += JT[i].MBBs.size();
1200 Offset *= EntrySize;
1202 return (uintptr_t)((char *)JumpTableBase + Offset);
1205 void JITEmitter::EmittedFunctionConfig::onDelete(
1206 JITEmitter *Emitter, const Function *F) {
1207 Emitter->deallocateMemForFunction(F);
1209 void JITEmitter::EmittedFunctionConfig::onRAUW(
1210 JITEmitter *, const Function*, const Function*) {
1211 llvm_unreachable("The JIT doesn't know how to handle a"
1212 " RAUW on a value it has emitted.");
1216 //===----------------------------------------------------------------------===//
1217 // Public interface to this file
1218 //===----------------------------------------------------------------------===//
1220 JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM,
1221 TargetMachine &tm) {
1222 return new JITEmitter(jit, JMM, tm);
1225 // getPointerToFunctionOrStub - If the specified function has been
1226 // code-gen'd, return a pointer to the function. If not, compile it, or use
1227 // a stub to implement lazy compilation if available.
1229 void *JIT::getPointerToFunctionOrStub(Function *F) {
1230 // If we have already code generated the function, just return the address.
1231 if (void *Addr = getPointerToGlobalIfAvailable(F))
1234 // Get a stub if the target supports it.
1235 JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
1236 return JE->getJITResolver().getLazyFunctionStub(F);
1239 void JIT::updateFunctionStubUnlocked(Function *F) {
1240 // Get the empty stub we generated earlier.
1241 JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
1242 void *Stub = JE->getJITResolver().getLazyFunctionStub(F);
1243 void *Addr = getPointerToGlobalIfAvailable(F);
1244 assert(Addr != Stub && "Function must have non-stub address to be updated.");
1246 // Tell the target jit info to rewrite the stub at the specified address,
1247 // rather than creating a new one.
1248 TargetJITInfo::StubLayout layout = getJITInfo().getStubLayout();
1249 JE->startGVStub(Stub, layout.Size);
1250 getJITInfo().emitFunctionStub(F, Addr, *getCodeEmitter());
1254 /// freeMachineCodeForFunction - release machine code memory for given Function.
1256 void JIT::freeMachineCodeForFunction(Function *F) {
1257 // Delete translation for this from the ExecutionEngine, so it will get
1258 // retranslated next time it is used.
1259 updateGlobalMapping(F, nullptr);
1261 // Free the actual memory for the function body and related stuff.
1262 static_cast<JITEmitter*>(JCE)->deallocateMemForFunction(F);