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 "JITDebugRegisterer.h"
18 #include "JITDwarfEmitter.h"
19 #include "llvm/ADT/OwningPtr.h"
20 #include "llvm/Constants.h"
21 #include "llvm/Module.h"
22 #include "llvm/DerivedTypes.h"
23 #include "llvm/CodeGen/JITCodeEmitter.h"
24 #include "llvm/CodeGen/MachineFunction.h"
25 #include "llvm/CodeGen/MachineConstantPool.h"
26 #include "llvm/CodeGen/MachineJumpTableInfo.h"
27 #include "llvm/CodeGen/MachineModuleInfo.h"
28 #include "llvm/CodeGen/MachineRelocation.h"
29 #include "llvm/ExecutionEngine/GenericValue.h"
30 #include "llvm/ExecutionEngine/JITEventListener.h"
31 #include "llvm/ExecutionEngine/JITMemoryManager.h"
32 #include "llvm/CodeGen/MachineCodeInfo.h"
33 #include "llvm/Target/TargetData.h"
34 #include "llvm/Target/TargetJITInfo.h"
35 #include "llvm/Target/TargetMachine.h"
36 #include "llvm/Target/TargetOptions.h"
37 #include "llvm/Support/Debug.h"
38 #include "llvm/Support/ErrorHandling.h"
39 #include "llvm/Support/MutexGuard.h"
40 #include "llvm/Support/ValueHandle.h"
41 #include "llvm/Support/raw_ostream.h"
42 #include "llvm/System/Disassembler.h"
43 #include "llvm/System/Memory.h"
44 #include "llvm/Target/TargetInstrInfo.h"
45 #include "llvm/ADT/DenseMap.h"
46 #include "llvm/ADT/SmallPtrSet.h"
47 #include "llvm/ADT/SmallVector.h"
48 #include "llvm/ADT/Statistic.h"
49 #include "llvm/ADT/ValueMap.h"
56 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
57 STATISTIC(NumRelos, "Number of relocations applied");
58 STATISTIC(NumRetries, "Number of retries with more memory");
59 static JIT *TheJIT = 0;
62 //===----------------------------------------------------------------------===//
63 // JIT lazy compilation code.
67 class JITResolverState;
69 template<typename ValueTy>
70 struct NoRAUWValueMapConfig : public ValueMapConfig<ValueTy> {
71 typedef JITResolverState *ExtraData;
72 static void onRAUW(JITResolverState *, Value *Old, Value *New) {
73 assert(false && "The JIT doesn't know how to handle a"
74 " RAUW on a value it has emitted.");
78 struct CallSiteValueMapConfig : public NoRAUWValueMapConfig<Function*> {
79 typedef JITResolverState *ExtraData;
80 static void onDelete(JITResolverState *JRS, Function *F);
83 class JITResolverState {
85 typedef ValueMap<Function*, void*, NoRAUWValueMapConfig<Function*> >
87 typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy;
88 typedef ValueMap<Function *, SmallPtrSet<void*, 1>,
89 CallSiteValueMapConfig> FunctionToCallSitesMapTy;
90 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
92 /// FunctionToStubMap - Keep track of the stub created for a particular
93 /// function so that we can reuse them if necessary.
94 FunctionToStubMapTy FunctionToStubMap;
96 /// CallSiteToFunctionMap - Keep track of the function that each lazy call
97 /// site corresponds to, and vice versa.
98 CallSiteToFunctionMapTy CallSiteToFunctionMap;
99 FunctionToCallSitesMapTy FunctionToCallSitesMap;
101 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
102 /// particular GlobalVariable so that we can reuse them if necessary.
103 GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
106 JITResolverState() : FunctionToStubMap(this),
107 FunctionToCallSitesMap(this) {}
109 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) {
110 assert(locked.holds(TheJIT->lock));
111 return FunctionToStubMap;
114 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) {
115 assert(locked.holds(TheJIT->lock));
116 return GlobalToIndirectSymMap;
119 pair<void *, Function *> LookupFunctionFromCallSite(
120 const MutexGuard &locked, void *CallSite) const {
121 assert(locked.holds(TheJIT->lock));
123 // The address given to us for the stub may not be exactly right, it might be
124 // a little bit after the stub. As such, use upper_bound to find it.
125 CallSiteToFunctionMapTy::const_iterator I =
126 CallSiteToFunctionMap.upper_bound(CallSite);
127 assert(I != CallSiteToFunctionMap.begin() &&
128 "This is not a known call site!");
133 void AddCallSite(const MutexGuard &locked, void *CallSite, Function *F) {
134 assert(locked.holds(TheJIT->lock));
136 bool Inserted = CallSiteToFunctionMap.insert(
137 std::make_pair(CallSite, F)).second;
139 assert(Inserted && "Pair was already in CallSiteToFunctionMap");
140 FunctionToCallSitesMap[F].insert(CallSite);
143 // Returns the Function of the stub if a stub was erased, or NULL if there
144 // was no stub. This function uses the call-site->function map to find a
145 // relevant function, but asserts that only stubs and not other call sites
146 // will be passed in.
147 Function *EraseStub(const MutexGuard &locked, void *Stub) {
148 CallSiteToFunctionMapTy::iterator C2F_I =
149 CallSiteToFunctionMap.find(Stub);
150 if (C2F_I == CallSiteToFunctionMap.end()) {
155 Function *const F = C2F_I->second;
157 void *RealStub = FunctionToStubMap.lookup(F);
158 assert(RealStub == Stub &&
159 "Call-site that wasn't a stub pass in to EraseStub");
161 FunctionToStubMap.erase(F);
162 CallSiteToFunctionMap.erase(C2F_I);
164 // Remove the stub from the function->call-sites map, and remove the whole
165 // entry from the map if that was the last call site.
166 FunctionToCallSitesMapTy::iterator F2C_I = FunctionToCallSitesMap.find(F);
167 assert(F2C_I != FunctionToCallSitesMap.end() &&
168 "FunctionToCallSitesMap broken");
169 bool Erased = F2C_I->second.erase(Stub);
171 assert(Erased && "FunctionToCallSitesMap broken");
172 if (F2C_I->second.empty())
173 FunctionToCallSitesMap.erase(F2C_I);
178 void EraseAllCallSites(const MutexGuard &locked, Function *F) {
179 assert(locked.holds(TheJIT->lock));
180 EraseAllCallSitesPrelocked(F);
182 void EraseAllCallSitesPrelocked(Function *F) {
183 FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F);
184 if (F2C == FunctionToCallSitesMap.end())
186 for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(),
187 E = F2C->second.end(); I != E; ++I) {
188 bool Erased = CallSiteToFunctionMap.erase(*I);
190 assert(Erased && "Missing call site->function mapping");
192 FunctionToCallSitesMap.erase(F2C);
196 /// JITResolver - Keep track of, and resolve, call sites for functions that
197 /// have not yet been compiled.
199 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy;
200 typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy;
201 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
203 /// LazyResolverFn - The target lazy resolver function that we actually
204 /// rewrite instructions to use.
205 TargetJITInfo::LazyResolverFn LazyResolverFn;
207 JITResolverState state;
209 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
210 /// external functions.
211 std::map<void*, void*> ExternalFnToStubMap;
213 /// revGOTMap - map addresses to indexes in the GOT
214 std::map<void*, unsigned> revGOTMap;
215 unsigned nextGOTIndex;
219 static JITResolver *TheJITResolver;
221 explicit JITResolver(JIT &jit, JITEmitter &je) : nextGOTIndex(0), JE(je) {
224 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
225 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
226 TheJITResolver = this;
233 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
234 /// if it has already been created.
235 void *getFunctionStubIfAvailable(Function *F);
237 /// getFunctionStub - This returns a pointer to a function stub, creating
238 /// one on demand as needed. If empty is true, create a function stub
239 /// pointing at address 0, to be filled in later.
240 void *getFunctionStub(Function *F);
242 /// getExternalFunctionStub - Return a stub for the function at the
243 /// specified address, created lazily on demand.
244 void *getExternalFunctionStub(void *FnAddr);
246 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
247 /// specified GV address.
248 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
250 /// AddCallbackAtLocation - If the target is capable of rewriting an
251 /// instruction without the use of a stub, record the location of the use so
252 /// we know which function is being used at the location.
253 void *AddCallbackAtLocation(Function *F, void *Location) {
254 MutexGuard locked(TheJIT->lock);
255 /// Get the target-specific JIT resolver function.
256 state.AddCallSite(locked, Location, F);
257 return (void*)(intptr_t)LazyResolverFn;
260 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
261 SmallVectorImpl<void*> &Ptrs);
263 GlobalValue *invalidateStub(void *Stub);
265 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
266 /// an address. This function only manages slots, it does not manage the
267 /// contents of the slots or the memory associated with the GOT.
268 unsigned getGOTIndexForAddr(void *addr);
270 /// JITCompilerFn - This function is called to resolve a stub to a compiled
271 /// address. If the LLVM Function corresponding to the stub has not yet
272 /// been compiled, this function compiles it first.
273 static void *JITCompilerFn(void *Stub);
276 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
277 /// used to output functions to memory for execution.
278 class JITEmitter : public JITCodeEmitter {
279 JITMemoryManager *MemMgr;
281 // When outputting a function stub in the context of some other function, we
282 // save BufferBegin/BufferEnd/CurBufferPtr here.
283 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
285 // When reattempting to JIT a function after running out of space, we store
286 // the estimated size of the function we're trying to JIT here, so we can
287 // ask the memory manager for at least this much space. When we
288 // successfully emit the function, we reset this back to zero.
289 uintptr_t SizeEstimate;
291 /// Relocations - These are the relocations that the function needs, as
293 std::vector<MachineRelocation> Relocations;
295 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
296 /// It is filled in by the StartMachineBasicBlock callback and queried by
297 /// the getMachineBasicBlockAddress callback.
298 std::vector<uintptr_t> MBBLocations;
300 /// ConstantPool - The constant pool for the current function.
302 MachineConstantPool *ConstantPool;
304 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
306 void *ConstantPoolBase;
308 /// ConstPoolAddresses - Addresses of individual constant pool entries.
310 SmallVector<uintptr_t, 8> ConstPoolAddresses;
312 /// JumpTable - The jump tables for the current function.
314 MachineJumpTableInfo *JumpTable;
316 /// JumpTableBase - A pointer to the first entry in the jump table.
320 /// Resolver - This contains info about the currently resolved functions.
321 JITResolver Resolver;
323 /// DE - The dwarf emitter for the jit.
324 OwningPtr<JITDwarfEmitter> DE;
326 /// DR - The debug registerer for the jit.
327 OwningPtr<JITDebugRegisterer> DR;
329 /// LabelLocations - This vector is a mapping from Label ID's to their
331 std::vector<uintptr_t> LabelLocations;
333 /// MMI - Machine module info for exception informations
334 MachineModuleInfo* MMI;
336 // GVSet - a set to keep track of which globals have been seen
337 SmallPtrSet<const GlobalVariable*, 8> GVSet;
339 // CurFn - The llvm function being emitted. Only valid during
341 const Function *CurFn;
343 /// Information about emitted code, which is passed to the
344 /// JITEventListeners. This is reset in startFunction and used in
346 JITEvent_EmittedFunctionDetails EmissionDetails;
349 void *FunctionBody; // Beginning of the function's allocation.
350 void *Code; // The address the function's code actually starts at.
351 void *ExceptionTable;
352 EmittedCode() : FunctionBody(0), Code(0), ExceptionTable(0) {}
354 struct EmittedFunctionConfig : public ValueMapConfig<const Function*> {
355 typedef JITEmitter *ExtraData;
356 static void onDelete(JITEmitter *, const Function*);
357 static void onRAUW(JITEmitter *, const Function*, const Function*);
359 ValueMap<const Function *, EmittedCode,
360 EmittedFunctionConfig> EmittedFunctions;
362 // CurFnStubUses - For a given Function, a vector of stubs that it
363 // references. This facilitates the JIT detecting that a stub is no
364 // longer used, so that it may be deallocated.
365 DenseMap<AssertingVH<const Function>, SmallVector<void*, 1> > CurFnStubUses;
367 // StubFnRefs - For a given pointer to a stub, a set of Functions which
368 // reference the stub. When the count of a stub's references drops to zero,
369 // the stub is unused.
370 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
372 // ExtFnStubs - A map of external function names to stubs which have entries
373 // in the JITResolver's ExternalFnToStubMap.
374 StringMap<void *> ExtFnStubs;
376 DebugLocTuple PrevDLT;
379 JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM)
380 : SizeEstimate(0), Resolver(jit, *this), MMI(0), CurFn(0),
381 EmittedFunctions(this) {
382 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
383 if (jit.getJITInfo().needsGOT()) {
384 MemMgr->AllocateGOT();
385 DEBUG(errs() << "JIT is managing a GOT\n");
388 if (DwarfExceptionHandling || JITEmitDebugInfo) {
389 DE.reset(new JITDwarfEmitter(jit));
391 if (JITEmitDebugInfo) {
392 DR.reset(new JITDebugRegisterer(TM));
399 /// classof - Methods for support type inquiry through isa, cast, and
402 static inline bool classof(const JITEmitter*) { return true; }
403 static inline bool classof(const MachineCodeEmitter*) { return true; }
405 JITResolver &getJITResolver() { return Resolver; }
407 virtual void startFunction(MachineFunction &F);
408 virtual bool finishFunction(MachineFunction &F);
410 void emitConstantPool(MachineConstantPool *MCP);
411 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
412 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
414 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
415 unsigned Alignment = 1);
416 virtual void startGVStub(const GlobalValue* GV, void *Buffer,
418 virtual void* finishGVStub(const GlobalValue *GV);
420 /// allocateSpace - Reserves space in the current block if any, or
421 /// allocate a new one of the given size.
422 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
424 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace,
425 /// this method does not allocate memory in the current output buffer,
426 /// because a global may live longer than the current function.
427 virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment);
429 virtual void addRelocation(const MachineRelocation &MR) {
430 Relocations.push_back(MR);
433 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
434 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
435 MBBLocations.resize((MBB->getNumber()+1)*2);
436 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
437 DEBUG(errs() << "JIT: Emitting BB" << MBB->getNumber() << " at ["
438 << (void*) getCurrentPCValue() << "]\n");
441 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
442 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
444 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
445 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
446 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
447 return MBBLocations[MBB->getNumber()];
450 /// retryWithMoreMemory - Log a retry and deallocate all memory for the
451 /// given function. Increase the minimum allocation size so that we get
452 /// more memory next time.
453 void retryWithMoreMemory(MachineFunction &F);
455 /// deallocateMemForFunction - Deallocate all memory for the specified
457 void deallocateMemForFunction(const Function *F);
459 /// AddStubToCurrentFunction - Mark the current function being JIT'd as
460 /// using the stub at the specified address. Allows
461 /// deallocateMemForFunction to also remove stubs no longer referenced.
462 void AddStubToCurrentFunction(void *Stub);
464 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
465 /// MachineRelocations that reference external functions by name.
466 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
468 virtual void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn);
470 virtual void emitLabel(uint64_t LabelID) {
471 if (LabelLocations.size() <= LabelID)
472 LabelLocations.resize((LabelID+1)*2);
473 LabelLocations[LabelID] = getCurrentPCValue();
476 virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
477 assert(LabelLocations.size() > (unsigned)LabelID &&
478 LabelLocations[LabelID] && "Label not emitted!");
479 return LabelLocations[LabelID];
482 virtual void setModuleInfo(MachineModuleInfo* Info) {
484 if (DE.get()) DE->setModuleInfo(Info);
487 void setMemoryExecutable() {
488 MemMgr->setMemoryExecutable();
491 JITMemoryManager *getMemMgr() const { return MemMgr; }
494 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
495 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
497 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
498 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
499 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
500 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
504 JITResolver *JITResolver::TheJITResolver = 0;
506 void CallSiteValueMapConfig::onDelete(JITResolverState *JRS, Function *F) {
507 JRS->EraseAllCallSitesPrelocked(F);
510 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
511 /// if it has already been created.
512 void *JITResolver::getFunctionStubIfAvailable(Function *F) {
513 MutexGuard locked(TheJIT->lock);
515 // If we already have a stub for this function, recycle it.
516 return state.getFunctionToStubMap(locked).lookup(F);
519 /// getFunctionStub - This returns a pointer to a function stub, creating
520 /// one on demand as needed.
521 void *JITResolver::getFunctionStub(Function *F) {
522 MutexGuard locked(TheJIT->lock);
524 // If we already have a stub for this function, recycle it.
525 void *&Stub = state.getFunctionToStubMap(locked)[F];
526 if (Stub) return Stub;
528 // Call the lazy resolver function if we are JIT'ing lazily. Otherwise we
529 // must resolve the symbol now.
530 void *Actual = TheJIT->isCompilingLazily()
531 ? (void *)(intptr_t)LazyResolverFn : (void *)0;
533 // If this is an external declaration, attempt to resolve the address now
534 // to place in the stub.
535 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
536 Actual = TheJIT->getPointerToFunction(F);
538 // If we resolved the symbol to a null address (eg. a weak external)
539 // don't emit a stub. Return a null pointer to the application. If dlsym
540 // stubs are enabled, not being able to resolve the address is not
542 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
545 // Codegen a new stub, calling the lazy resolver or the actual address of the
546 // external function, if it was resolved.
547 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual, JE);
549 if (Actual != (void*)(intptr_t)LazyResolverFn) {
550 // If we are getting the stub for an external function, we really want the
551 // address of the stub in the GlobalAddressMap for the JIT, not the address
552 // of the external function.
553 TheJIT->updateGlobalMapping(F, Stub);
556 DEBUG(errs() << "JIT: Stub emitted at [" << Stub << "] for function '"
557 << F->getName() << "'\n");
559 // Finally, keep track of the stub-to-Function mapping so that the
560 // JITCompilerFn knows which function to compile!
561 state.AddCallSite(locked, Stub, F);
563 // If we are JIT'ing non-lazily but need to call a function that does not
564 // exist yet, add it to the JIT's work list so that we can fill in the stub
566 if (!Actual && !TheJIT->isCompilingLazily())
567 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
568 TheJIT->addPendingFunction(F);
573 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
575 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
576 MutexGuard locked(TheJIT->lock);
578 // If we already have a stub for this global variable, recycle it.
579 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
580 if (IndirectSym) return IndirectSym;
582 // Otherwise, codegen a new indirect symbol.
583 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
586 DEBUG(errs() << "JIT: Indirect symbol emitted at [" << IndirectSym
587 << "] for GV '" << GV->getName() << "'\n");
592 /// getExternalFunctionStub - Return a stub for the function at the
593 /// specified address, created lazily on demand.
594 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
595 // If we already have a stub for this function, recycle it.
596 void *&Stub = ExternalFnToStubMap[FnAddr];
597 if (Stub) return Stub;
599 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr, JE);
601 DEBUG(errs() << "JIT: Stub emitted at [" << Stub
602 << "] for external function at '" << FnAddr << "'\n");
606 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
607 unsigned idx = revGOTMap[addr];
609 idx = ++nextGOTIndex;
610 revGOTMap[addr] = idx;
611 DEBUG(errs() << "JIT: Adding GOT entry " << idx << " for addr ["
617 void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
618 SmallVectorImpl<void*> &Ptrs) {
619 MutexGuard locked(TheJIT->lock);
621 const FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
622 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
624 for (FunctionToStubMapTy::const_iterator i = FM.begin(), e = FM.end();
626 Function *F = i->first;
627 if (F->isDeclaration() && F->hasExternalLinkage()) {
628 GVs.push_back(i->first);
629 Ptrs.push_back(i->second);
632 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
634 GVs.push_back(i->first);
635 Ptrs.push_back(i->second);
639 GlobalValue *JITResolver::invalidateStub(void *Stub) {
640 MutexGuard locked(TheJIT->lock);
642 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
644 // Look up the cheap way first, to see if it's a function stub we are
645 // invalidating. If so, remove it from both the forward and reverse maps.
646 if (Function *F = state.EraseStub(locked, Stub)) {
650 // Otherwise, it might be an indirect symbol stub. Find it and remove it.
651 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
653 if (i->second != Stub)
655 GlobalValue *GV = i->first;
660 // Lastly, check to see if it's in the ExternalFnToStubMap.
661 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
662 e = ExternalFnToStubMap.end(); i != e; ++i) {
663 if (i->second != Stub)
665 ExternalFnToStubMap.erase(i);
672 /// JITCompilerFn - This function is called when a lazy compilation stub has
673 /// been entered. It looks up which function this stub corresponds to, compiles
674 /// it if necessary, then returns the resultant function pointer.
675 void *JITResolver::JITCompilerFn(void *Stub) {
676 JITResolver &JR = *TheJITResolver;
682 // Only lock for getting the Function. The call getPointerToFunction made
683 // in this function might trigger function materializing, which requires
684 // JIT lock to be unlocked.
685 MutexGuard locked(TheJIT->lock);
687 // The address given to us for the stub may not be exactly right, it might
688 // be a little bit after the stub. As such, use upper_bound to find it.
689 pair<void*, Function*> I =
690 JR.state.LookupFunctionFromCallSite(locked, Stub);
695 // If we have already code generated the function, just return the address.
696 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
699 // Otherwise we don't have it, do lazy compilation now.
701 // If lazy compilation is disabled, emit a useful error message and abort.
702 if (!TheJIT->isCompilingLazily()) {
703 llvm_report_error("LLVM JIT requested to do lazy compilation of function '"
704 + F->getName() + "' when lazy compiles are disabled!");
707 DEBUG(errs() << "JIT: Lazily resolving function '" << F->getName()
708 << "' In stub ptr = " << Stub << " actual ptr = "
709 << ActualPtr << "\n");
711 Result = TheJIT->getPointerToFunction(F);
714 // Reacquire the lock to update the GOT map.
715 MutexGuard locked(TheJIT->lock);
717 // We might like to remove the call site from the CallSiteToFunction map, but
718 // we can't do that! Multiple threads could be stuck, waiting to acquire the
719 // lock above. As soon as the 1st function finishes compiling the function,
720 // the next one will be released, and needs to be able to find the function it
723 // FIXME: We could rewrite all references to this stub if we knew them.
725 // What we will do is set the compiled function address to map to the
726 // same GOT entry as the stub so that later clients may update the GOT
727 // if they see it still using the stub address.
728 // Note: this is done so the Resolver doesn't have to manage GOT memory
729 // Do this without allocating map space if the target isn't using a GOT
730 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
731 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
736 //===----------------------------------------------------------------------===//
739 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
740 bool DoesntNeedStub) {
741 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
742 return TheJIT->getOrEmitGlobalVariable(GV);
744 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
745 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
747 // If we have already compiled the function, return a pointer to its body.
748 Function *F = cast<Function>(V);
750 if (!DoesntNeedStub) {
751 // Return the function stub if it's already created.
752 ResultPtr = Resolver.getFunctionStubIfAvailable(F);
754 AddStubToCurrentFunction(ResultPtr);
756 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
758 if (ResultPtr) return ResultPtr;
760 // If this is an external function pointer, we can force the JIT to
761 // 'compile' it, which really just adds it to the map. In dlsym mode,
762 // external functions are forced through a stub, regardless of reloc type.
763 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
764 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
765 return TheJIT->getPointerToFunction(F);
767 // Okay, the function has not been compiled yet, if the target callback
768 // mechanism is capable of rewriting the instruction directly, prefer to do
769 // that instead of emitting a stub. This uses the lazy resolver, so is not
770 // legal if lazy compilation is disabled.
771 if (DoesntNeedStub && TheJIT->isCompilingLazily())
772 return Resolver.AddCallbackAtLocation(F, Reference);
774 // Otherwise, we have to emit a stub.
775 void *StubAddr = Resolver.getFunctionStub(F);
777 // Add the stub to the current function's list of referenced stubs, so we can
778 // deallocate them if the current function is ever freed. It's possible to
779 // return null from getFunctionStub in the case of a weak extern that fails
782 AddStubToCurrentFunction(StubAddr);
787 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
789 // Make sure GV is emitted first, and create a stub containing the fully
791 void *GVAddress = getPointerToGlobal(V, Reference, true);
792 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
794 // Add the stub to the current function's list of referenced stubs, so we can
795 // deallocate them if the current function is ever freed.
796 AddStubToCurrentFunction(StubAddr);
801 void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
802 assert(CurFn && "Stub added to current function, but current function is 0!");
804 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
805 StubsUsed.push_back(StubAddr);
807 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
808 FnRefs.insert(CurFn);
811 void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
812 if (!DL.isUnknown()) {
813 DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL);
815 if (BeforePrintingInsn) {
816 if (CurDLT.Scope != 0 && PrevDLT != CurDLT) {
817 JITEvent_EmittedFunctionDetails::LineStart NextLine;
818 NextLine.Address = getCurrentPCValue();
820 EmissionDetails.LineStarts.push_back(NextLine);
828 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
829 const TargetData *TD) {
830 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
831 if (Constants.empty()) return 0;
834 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
835 MachineConstantPoolEntry CPE = Constants[i];
836 unsigned AlignMask = CPE.getAlignment() - 1;
837 Size = (Size + AlignMask) & ~AlignMask;
838 const Type *Ty = CPE.getType();
839 Size += TD->getTypeAllocSize(Ty);
844 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
845 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
846 if (JT.empty()) return 0;
848 unsigned NumEntries = 0;
849 for (unsigned i = 0, e = JT.size(); i != e; ++i)
850 NumEntries += JT[i].MBBs.size();
852 unsigned EntrySize = MJTI->getEntrySize();
854 return NumEntries * EntrySize;
857 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
858 if (Alignment == 0) Alignment = 1;
859 // Since we do not know where the buffer will be allocated, be pessimistic.
860 return Size + Alignment;
863 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
864 /// into the running total Size.
866 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
867 const Type *ElTy = GV->getType()->getElementType();
868 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy);
870 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
871 DEBUG(errs() << "JIT: Adding in size " << GVSize << " alignment " << GVAlign);
873 // Assume code section ends with worst possible alignment, so first
874 // variable needs maximal padding.
877 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
882 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
883 /// but are referenced from the constant; put them in GVSet and add their
884 /// size into the running total Size.
886 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
888 // If its undefined, return the garbage.
889 if (isa<UndefValue>(C))
892 // If the value is a ConstantExpr
893 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
894 Constant *Op0 = CE->getOperand(0);
895 switch (CE->getOpcode()) {
896 case Instruction::GetElementPtr:
897 case Instruction::Trunc:
898 case Instruction::ZExt:
899 case Instruction::SExt:
900 case Instruction::FPTrunc:
901 case Instruction::FPExt:
902 case Instruction::UIToFP:
903 case Instruction::SIToFP:
904 case Instruction::FPToUI:
905 case Instruction::FPToSI:
906 case Instruction::PtrToInt:
907 case Instruction::IntToPtr:
908 case Instruction::BitCast: {
909 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
912 case Instruction::Add:
913 case Instruction::FAdd:
914 case Instruction::Sub:
915 case Instruction::FSub:
916 case Instruction::Mul:
917 case Instruction::FMul:
918 case Instruction::UDiv:
919 case Instruction::SDiv:
920 case Instruction::URem:
921 case Instruction::SRem:
922 case Instruction::And:
923 case Instruction::Or:
924 case Instruction::Xor: {
925 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
926 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
931 raw_string_ostream Msg(msg);
932 Msg << "ConstantExpr not handled: " << *CE;
933 llvm_report_error(Msg.str());
938 if (C->getType()->getTypeID() == Type::PointerTyID)
939 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
940 if (GVSet.insert(GV))
941 Size = addSizeOfGlobal(GV, Size);
946 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
947 /// but are referenced from the given initializer.
949 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
951 if (!isa<UndefValue>(Init) &&
952 !isa<ConstantVector>(Init) &&
953 !isa<ConstantAggregateZero>(Init) &&
954 !isa<ConstantArray>(Init) &&
955 !isa<ConstantStruct>(Init) &&
956 Init->getType()->isFirstClassType())
957 Size = addSizeOfGlobalsInConstantVal(Init, Size);
961 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
962 /// globals; then walk the initializers of those globals looking for more.
963 /// If their size has not been considered yet, add it into the running total
966 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
970 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
972 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
974 const TargetInstrDesc &Desc = I->getDesc();
975 const MachineInstr &MI = *I;
976 unsigned NumOps = Desc.getNumOperands();
977 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
978 const MachineOperand &MO = MI.getOperand(CurOp);
980 GlobalValue* V = MO.getGlobal();
981 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
984 // If seen in previous function, it will have an entry here.
985 if (TheJIT->getPointerToGlobalIfAvailable(GV))
987 // If seen earlier in this function, it will have an entry here.
988 // FIXME: it should be possible to combine these tables, by
989 // assuming the addresses of the new globals in this module
990 // start at 0 (or something) and adjusting them after codegen
991 // complete. Another possibility is to grab a marker bit in GV.
992 if (GVSet.insert(GV))
993 // A variable as yet unseen. Add in its size.
994 Size = addSizeOfGlobal(GV, Size);
999 DEBUG(errs() << "JIT: About to look through initializers\n");
1000 // Look for more globals that are referenced only from initializers.
1001 // GVSet.end is computed each time because the set can grow as we go.
1002 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin();
1003 I != GVSet.end(); I++) {
1004 const GlobalVariable* GV = *I;
1005 if (GV->hasInitializer())
1006 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
1012 void JITEmitter::startFunction(MachineFunction &F) {
1013 DEBUG(errs() << "JIT: Starting CodeGen of Function "
1014 << F.getFunction()->getName() << "\n");
1016 uintptr_t ActualSize = 0;
1017 // Set the memory writable, if it's not already
1018 MemMgr->setMemoryWritable();
1019 if (MemMgr->NeedsExactSize()) {
1020 DEBUG(errs() << "JIT: ExactSize\n");
1021 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
1022 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
1023 MachineConstantPool *MCP = F.getConstantPool();
1025 // Ensure the constant pool/jump table info is at least 4-byte aligned.
1026 ActualSize = RoundUpToAlign(ActualSize, 16);
1028 // Add the alignment of the constant pool
1029 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment());
1031 // Add the constant pool size
1032 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
1034 // Add the aligment of the jump table info
1035 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
1037 // Add the jump table size
1038 ActualSize += GetJumpTableSizeInBytes(MJTI);
1040 // Add the alignment for the function
1041 ActualSize = RoundUpToAlign(ActualSize,
1042 std::max(F.getFunction()->getAlignment(), 8U));
1044 // Add the function size
1045 ActualSize += TII->GetFunctionSizeInBytes(F);
1047 DEBUG(errs() << "JIT: ActualSize before globals " << ActualSize << "\n");
1048 // Add the size of the globals that will be allocated after this function.
1049 // These are all the ones referenced from this function that were not
1050 // previously allocated.
1051 ActualSize += GetSizeOfGlobalsInBytes(F);
1052 DEBUG(errs() << "JIT: ActualSize after globals " << ActualSize << "\n");
1053 } else if (SizeEstimate > 0) {
1054 // SizeEstimate will be non-zero on reallocation attempts.
1055 ActualSize = SizeEstimate;
1058 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
1060 BufferEnd = BufferBegin+ActualSize;
1061 EmittedFunctions[F.getFunction()].FunctionBody = BufferBegin;
1063 // Ensure the constant pool/jump table info is at least 4-byte aligned.
1066 emitConstantPool(F.getConstantPool());
1067 initJumpTableInfo(F.getJumpTableInfo());
1069 // About to start emitting the machine code for the function.
1070 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
1071 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
1072 EmittedFunctions[F.getFunction()].Code = CurBufferPtr;
1074 MBBLocations.clear();
1076 EmissionDetails.MF = &F;
1077 EmissionDetails.LineStarts.clear();
1080 bool JITEmitter::finishFunction(MachineFunction &F) {
1081 if (CurBufferPtr == BufferEnd) {
1082 // We must call endFunctionBody before retrying, because
1083 // deallocateMemForFunction requires it.
1084 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
1085 retryWithMoreMemory(F);
1089 emitJumpTableInfo(F.getJumpTableInfo());
1091 // FnStart is the start of the text, not the start of the constant pool and
1092 // other per-function data.
1094 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
1096 // FnEnd is the end of the function's machine code.
1097 uint8_t *FnEnd = CurBufferPtr;
1099 if (!Relocations.empty()) {
1100 CurFn = F.getFunction();
1101 NumRelos += Relocations.size();
1103 // Resolve the relocations to concrete pointers.
1104 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
1105 MachineRelocation &MR = Relocations[i];
1106 void *ResultPtr = 0;
1107 if (!MR.letTargetResolve()) {
1108 if (MR.isExternalSymbol()) {
1109 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
1111 DEBUG(errs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
1112 << ResultPtr << "]\n");
1114 // If the target REALLY wants a stub for this function, emit it now.
1115 if (!MR.doesntNeedStub()) {
1116 if (!TheJIT->areDlsymStubsEnabled()) {
1117 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
1119 void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
1121 Stub = Resolver.getExternalFunctionStub((void *)&Stub);
1122 AddStubToCurrentFunction(Stub);
1127 } else if (MR.isGlobalValue()) {
1128 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
1129 BufferBegin+MR.getMachineCodeOffset(),
1130 MR.doesntNeedStub());
1131 } else if (MR.isIndirectSymbol()) {
1132 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
1133 BufferBegin+MR.getMachineCodeOffset(),
1134 MR.doesntNeedStub());
1135 } else if (MR.isBasicBlock()) {
1136 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
1137 } else if (MR.isConstantPoolIndex()) {
1138 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
1140 assert(MR.isJumpTableIndex());
1141 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
1144 MR.setResultPointer(ResultPtr);
1147 // if we are managing the GOT and the relocation wants an index,
1149 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
1150 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
1151 MR.setGOTIndex(idx);
1152 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
1153 DEBUG(errs() << "JIT: GOT was out of date for " << ResultPtr
1154 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1156 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
1162 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
1163 Relocations.size(), MemMgr->getGOTBase());
1166 // Update the GOT entry for F to point to the new code.
1167 if (MemMgr->isManagingGOT()) {
1168 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
1169 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
1170 DEBUG(errs() << "JIT: GOT was out of date for " << (void*)BufferBegin
1171 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1173 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
1177 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
1178 // global variables that were referenced in the relocations.
1179 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
1181 if (CurBufferPtr == BufferEnd) {
1182 retryWithMoreMemory(F);
1185 // Now that we've succeeded in emitting the function, reset the
1186 // SizeEstimate back down to zero.
1190 BufferBegin = CurBufferPtr = 0;
1191 NumBytes += FnEnd-FnStart;
1193 // Invalidate the icache if necessary.
1194 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
1196 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
1199 DEBUG(errs() << "JIT: Finished CodeGen of [" << (void*)FnStart
1200 << "] Function: " << F.getFunction()->getName()
1201 << ": " << (FnEnd-FnStart) << " bytes of text, "
1202 << Relocations.size() << " relocations\n");
1204 Relocations.clear();
1205 ConstPoolAddresses.clear();
1207 // Mark code region readable and executable if it's not so already.
1208 MemMgr->setMemoryExecutable();
1211 if (sys::hasDisassembler()) {
1212 errs() << "JIT: Disassembled code:\n";
1213 errs() << sys::disassembleBuffer(FnStart, FnEnd-FnStart,
1214 (uintptr_t)FnStart);
1216 errs() << "JIT: Binary code:\n";
1217 uint8_t* q = FnStart;
1218 for (int i = 0; q < FnEnd; q += 4, ++i) {
1222 errs() << "JIT: " << (long)(q - FnStart) << ": ";
1224 for (int j = 3; j >= 0; --j) {
1228 errs() << (unsigned short)q[j];
1240 if (DwarfExceptionHandling || JITEmitDebugInfo) {
1241 uintptr_t ActualSize = 0;
1242 SavedBufferBegin = BufferBegin;
1243 SavedBufferEnd = BufferEnd;
1244 SavedCurBufferPtr = CurBufferPtr;
1246 if (MemMgr->NeedsExactSize()) {
1247 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
1250 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
1252 BufferEnd = BufferBegin+ActualSize;
1253 EmittedFunctions[F.getFunction()].ExceptionTable = BufferBegin;
1255 uint8_t *FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd,
1257 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
1259 uint8_t *EhEnd = CurBufferPtr;
1260 BufferBegin = SavedBufferBegin;
1261 BufferEnd = SavedBufferEnd;
1262 CurBufferPtr = SavedCurBufferPtr;
1264 if (DwarfExceptionHandling) {
1265 TheJIT->RegisterTable(FrameRegister);
1268 if (JITEmitDebugInfo) {
1270 I.FnStart = FnStart;
1272 I.EhStart = EhStart;
1274 DR->RegisterFunction(F.getFunction(), I);
1284 void JITEmitter::retryWithMoreMemory(MachineFunction &F) {
1285 DEBUG(errs() << "JIT: Ran out of space for native code. Reattempting.\n");
1286 Relocations.clear(); // Clear the old relocations or we'll reapply them.
1287 ConstPoolAddresses.clear();
1289 deallocateMemForFunction(F.getFunction());
1290 // Try again with at least twice as much free space.
1291 SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin));
1294 /// deallocateMemForFunction - Deallocate all memory for the specified
1295 /// function body. Also drop any references the function has to stubs.
1296 /// May be called while the Function is being destroyed inside ~Value().
1297 void JITEmitter::deallocateMemForFunction(const Function *F) {
1298 ValueMap<const Function *, EmittedCode, EmittedFunctionConfig>::iterator
1299 Emitted = EmittedFunctions.find(F);
1300 if (Emitted != EmittedFunctions.end()) {
1301 MemMgr->deallocateFunctionBody(Emitted->second.FunctionBody);
1302 MemMgr->deallocateExceptionTable(Emitted->second.ExceptionTable);
1303 TheJIT->NotifyFreeingMachineCode(Emitted->second.Code);
1305 EmittedFunctions.erase(Emitted);
1308 // TODO: Do we need to unregister exception handling information from libgcc
1311 if (JITEmitDebugInfo) {
1312 DR->UnregisterFunction(F);
1315 // If the function did not reference any stubs, return.
1316 if (CurFnStubUses.find(F) == CurFnStubUses.end())
1319 // For each referenced stub, erase the reference to this function, and then
1320 // erase the list of referenced stubs.
1321 SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
1322 for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
1323 void *Stub = StubList[i];
1325 // If we already invalidated this stub for this function, continue.
1326 if (StubFnRefs.count(Stub) == 0)
1329 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
1332 // If this function was the last reference to the stub, invalidate the stub
1333 // in the JITResolver. Were there a memory manager deallocateStub routine,
1334 // we could call that at this point too.
1335 if (FnRefs.empty()) {
1336 DEBUG(errs() << "\nJIT: Invalidated Stub at [" << Stub << "]\n");
1337 StubFnRefs.erase(Stub);
1339 // Invalidate the stub. If it is a GV stub, update the JIT's global
1340 // mapping for that GV to zero, otherwise, search the string map of
1341 // external function names to stubs and remove the entry for this stub.
1342 GlobalValue *GV = Resolver.invalidateStub(Stub);
1344 TheJIT->updateGlobalMapping(GV, 0);
1346 for (StringMapIterator<void*> i = ExtFnStubs.begin(),
1347 e = ExtFnStubs.end(); i != e; ++i) {
1348 if (i->second == Stub) {
1349 ExtFnStubs.erase(i);
1356 CurFnStubUses.erase(F);
1360 void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1362 return JITCodeEmitter::allocateSpace(Size, Alignment);
1364 // create a new memory block if there is no active one.
1365 // care must be taken so that BufferBegin is invalidated when a
1367 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1368 BufferEnd = BufferBegin+Size;
1369 return CurBufferPtr;
1372 void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
1373 // Delegate this call through the memory manager.
1374 return MemMgr->allocateGlobal(Size, Alignment);
1377 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1378 if (TheJIT->getJITInfo().hasCustomConstantPool())
1381 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1382 if (Constants.empty()) return;
1384 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
1385 unsigned Align = MCP->getConstantPoolAlignment();
1386 ConstantPoolBase = allocateSpace(Size, Align);
1389 if (ConstantPoolBase == 0) return; // Buffer overflow.
1391 DEBUG(errs() << "JIT: Emitted constant pool at [" << ConstantPoolBase
1392 << "] (size: " << Size << ", alignment: " << Align << ")\n");
1394 // Initialize the memory for all of the constant pool entries.
1395 unsigned Offset = 0;
1396 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1397 MachineConstantPoolEntry CPE = Constants[i];
1398 unsigned AlignMask = CPE.getAlignment() - 1;
1399 Offset = (Offset + AlignMask) & ~AlignMask;
1401 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
1402 ConstPoolAddresses.push_back(CAddr);
1403 if (CPE.isMachineConstantPoolEntry()) {
1404 // FIXME: add support to lower machine constant pool values into bytes!
1405 llvm_report_error("Initialize memory with machine specific constant pool"
1406 "entry has not been implemented!");
1408 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
1409 DEBUG(errs() << "JIT: CP" << i << " at [0x";
1410 errs().write_hex(CAddr) << "]\n");
1412 const Type *Ty = CPE.Val.ConstVal->getType();
1413 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty);
1417 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1418 if (TheJIT->getJITInfo().hasCustomJumpTables())
1421 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1422 if (JT.empty()) return;
1424 unsigned NumEntries = 0;
1425 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1426 NumEntries += JT[i].MBBs.size();
1428 unsigned EntrySize = MJTI->getEntrySize();
1430 // Just allocate space for all the jump tables now. We will fix up the actual
1431 // MBB entries in the tables after we emit the code for each block, since then
1432 // we will know the final locations of the MBBs in memory.
1434 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1437 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1438 if (TheJIT->getJITInfo().hasCustomJumpTables())
1441 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1442 if (JT.empty() || JumpTableBase == 0) return;
1444 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1445 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1446 // For each jump table, place the offset from the beginning of the table
1447 // to the target address.
1448 int *SlotPtr = (int*)JumpTableBase;
1450 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1451 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1452 // Store the offset of the basic block for this jump table slot in the
1453 // memory we allocated for the jump table in 'initJumpTableInfo'
1454 uintptr_t Base = (uintptr_t)SlotPtr;
1455 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1456 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1457 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1461 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1463 // For each jump table, map each target in the jump table to the address of
1464 // an emitted MachineBasicBlock.
1465 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1467 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1468 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1469 // Store the address of the basic block for this jump table slot in the
1470 // memory we allocated for the jump table in 'initJumpTableInfo'
1471 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1472 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1477 void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
1478 unsigned Alignment) {
1479 SavedBufferBegin = BufferBegin;
1480 SavedBufferEnd = BufferEnd;
1481 SavedCurBufferPtr = CurBufferPtr;
1483 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1484 BufferEnd = BufferBegin+StubSize+1;
1487 void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
1488 unsigned StubSize) {
1489 SavedBufferBegin = BufferBegin;
1490 SavedBufferEnd = BufferEnd;
1491 SavedCurBufferPtr = CurBufferPtr;
1493 BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
1494 BufferEnd = BufferBegin+StubSize+1;
1497 void *JITEmitter::finishGVStub(const GlobalValue* GV) {
1498 NumBytes += getCurrentPCOffset();
1499 std::swap(SavedBufferBegin, BufferBegin);
1500 BufferEnd = SavedBufferEnd;
1501 CurBufferPtr = SavedCurBufferPtr;
1502 return SavedBufferBegin;
1505 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1506 // in the constant pool that was last emitted with the 'emitConstantPool'
1509 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1510 assert(ConstantNum < ConstantPool->getConstants().size() &&
1511 "Invalid ConstantPoolIndex!");
1512 return ConstPoolAddresses[ConstantNum];
1515 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1516 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1518 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1519 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1520 assert(Index < JT.size() && "Invalid jump table index!");
1522 unsigned Offset = 0;
1523 unsigned EntrySize = JumpTable->getEntrySize();
1525 for (unsigned i = 0; i < Index; ++i)
1526 Offset += JT[i].MBBs.size();
1528 Offset *= EntrySize;
1530 return (uintptr_t)((char *)JumpTableBase + Offset);
1533 void JITEmitter::EmittedFunctionConfig::onDelete(
1534 JITEmitter *Emitter, const Function *F) {
1535 Emitter->deallocateMemForFunction(F);
1537 void JITEmitter::EmittedFunctionConfig::onRAUW(
1538 JITEmitter *, const Function*, const Function*) {
1539 llvm_unreachable("The JIT doesn't know how to handle a"
1540 " RAUW on a value it has emitted.");
1544 //===----------------------------------------------------------------------===//
1545 // Public interface to this file
1546 //===----------------------------------------------------------------------===//
1548 JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM,
1549 TargetMachine &tm) {
1550 return new JITEmitter(jit, JMM, tm);
1553 // getPointerToNamedFunction - This function is used as a global wrapper to
1554 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1555 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1556 // need to resolve function(s) that are being mis-codegenerated, so we need to
1557 // resolve their addresses at runtime, and this is the way to do it.
1559 void *getPointerToNamedFunction(const char *Name) {
1560 if (Function *F = TheJIT->FindFunctionNamed(Name))
1561 return TheJIT->getPointerToFunction(F);
1562 return TheJIT->getPointerToNamedFunction(Name);
1566 // getPointerToFunctionOrStub - If the specified function has been
1567 // code-gen'd, return a pointer to the function. If not, compile it, or use
1568 // a stub to implement lazy compilation if available.
1570 void *JIT::getPointerToFunctionOrStub(Function *F) {
1571 // If we have already code generated the function, just return the address.
1572 if (void *Addr = getPointerToGlobalIfAvailable(F))
1575 // Get a stub if the target supports it.
1576 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1577 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1578 return JE->getJITResolver().getFunctionStub(F);
1581 void JIT::updateFunctionStub(Function *F) {
1582 // Get the empty stub we generated earlier.
1583 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1584 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1585 void *Stub = JE->getJITResolver().getFunctionStub(F);
1587 // Tell the target jit info to rewrite the stub at the specified address,
1588 // rather than creating a new one.
1589 void *Addr = getPointerToGlobalIfAvailable(F);
1590 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
1593 /// updateDlsymStubTable - Emit the data necessary to relocate the stubs
1594 /// that were emitted during code generation.
1596 void JIT::updateDlsymStubTable() {
1597 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1598 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1600 SmallVector<GlobalValue*, 8> GVs;
1601 SmallVector<void*, 8> Ptrs;
1602 const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
1604 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
1606 unsigned nStubs = GVs.size() + ExtFns.size();
1608 // If there are no relocatable stubs, return.
1612 // If there are no new relocatable stubs, return.
1613 void *CurTable = JE->getMemMgr()->getDlsymTable();
1614 if (CurTable && (*(unsigned *)CurTable == nStubs))
1617 // Calculate the size of the stub info
1618 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
1620 SmallVector<unsigned, 8> Offsets;
1621 for (unsigned i = 0; i != GVs.size(); ++i) {
1622 Offsets.push_back(offset);
1623 offset += GVs[i]->getName().size() + 1;
1625 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1627 Offsets.push_back(offset);
1628 offset += strlen(i->first()) + 1;
1631 // Allocate space for the new "stub", which contains the dlsym table.
1632 JE->startGVStub(0, offset, 4);
1634 // Emit the number of records
1635 JE->emitInt32(nStubs);
1637 // Emit the string offsets
1638 for (unsigned i = 0; i != nStubs; ++i)
1639 JE->emitInt32(Offsets[i]);
1641 // Emit the pointers. Verify that they are at least 2-byte aligned, and set
1642 // the low bit to 0 == GV, 1 == Function, so that the client code doing the
1643 // relocation can write the relocated pointer at the appropriate place in
1645 for (unsigned i = 0; i != GVs.size(); ++i) {
1646 intptr_t Ptr = (intptr_t)Ptrs[i];
1647 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
1649 if (isa<Function>(GVs[i]))
1652 if (sizeof(Ptr) == 8)
1657 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1659 intptr_t Ptr = (intptr_t)i->second | 1;
1661 if (sizeof(Ptr) == 8)
1667 // Emit the strings.
1668 for (unsigned i = 0; i != GVs.size(); ++i)
1669 JE->emitString(GVs[i]->getName());
1670 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1672 JE->emitString(i->first());
1674 // Tell the JIT memory manager where it is. The JIT Memory Manager will
1675 // deallocate space for the old one, if one existed.
1676 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
1679 /// freeMachineCodeForFunction - release machine code memory for given Function.
1681 void JIT::freeMachineCodeForFunction(Function *F) {
1682 // Delete translation for this from the ExecutionEngine, so it will get
1683 // retranslated next time it is used.
1684 updateGlobalMapping(F, 0);
1686 // Free the actual memory for the function body and related stuff.
1687 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1688 cast<JITEmitter>(JCE)->deallocateMemForFunction(F);