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/SmallPtrSet.h"
46 #include "llvm/ADT/SmallVector.h"
47 #include "llvm/ADT/Statistic.h"
54 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
55 STATISTIC(NumRelos, "Number of relocations applied");
56 STATISTIC(NumRetries, "Number of retries with more memory");
57 static JIT *TheJIT = 0;
60 //===----------------------------------------------------------------------===//
61 // JIT lazy compilation code.
64 class JITResolverState {
66 typedef DenseMap<AssertingVH<Function>, void*> FunctionToStubMapTy;
67 typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy;
68 typedef DenseMap<AssertingVH<Function>, SmallPtrSet<void*, 1> >
69 FunctionToCallSitesMapTy;
70 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
72 /// FunctionToStubMap - Keep track of the stub created for a particular
73 /// function so that we can reuse them if necessary.
74 FunctionToStubMapTy FunctionToStubMap;
76 /// CallSiteToFunctionMap - Keep track of the function that each lazy call
77 /// site corresponds to, and vice versa.
78 CallSiteToFunctionMapTy CallSiteToFunctionMap;
79 FunctionToCallSitesMapTy FunctionToCallSitesMap;
81 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
82 /// particular GlobalVariable so that we can reuse them if necessary.
83 GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
86 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) {
87 assert(locked.holds(TheJIT->lock));
88 return FunctionToStubMap;
91 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) {
92 assert(locked.holds(TheJIT->lock));
93 return GlobalToIndirectSymMap;
96 pair<void *, Function *> LookupFunctionFromCallSite(
97 const MutexGuard &locked, void *CallSite) const {
98 assert(locked.holds(TheJIT->lock));
100 // The address given to us for the stub may not be exactly right, it might be
101 // a little bit after the stub. As such, use upper_bound to find it.
102 CallSiteToFunctionMapTy::const_iterator I =
103 CallSiteToFunctionMap.upper_bound(CallSite);
104 assert(I != CallSiteToFunctionMap.begin() &&
105 "This is not a known call site!");
110 void AddCallSite(const MutexGuard &locked, void *CallSite, Function *F) {
111 assert(locked.holds(TheJIT->lock));
113 assert(CallSiteToFunctionMap.insert(std::make_pair(CallSite, F)).second &&
114 "Pair was already in CallSiteToFunctionMap");
115 FunctionToCallSitesMap[F].insert(CallSite);
118 // Returns the Function of the stub if a stub was erased, or NULL if there
119 // was no stub. This function uses the call-site->function map to find a
120 // relevant function, but asserts that only stubs and not other call sites
121 // will be passed in.
122 Function *EraseStub(const MutexGuard &locked, void *Stub) {
123 CallSiteToFunctionMapTy::iterator C2F_I =
124 CallSiteToFunctionMap.find(Stub);
125 if (C2F_I == CallSiteToFunctionMap.end()) {
130 Function *const F = C2F_I->second;
132 void *RealStub = FunctionToStubMap.lookup(F);
133 assert(RealStub == Stub &&
134 "Call-site that wasn't a stub pass in to EraseStub");
136 FunctionToStubMap.erase(F);
137 CallSiteToFunctionMap.erase(C2F_I);
139 // Remove the stub from the function->call-sites map, and remove the whole
140 // entry from the map if that was the last call site.
141 FunctionToCallSitesMapTy::iterator F2C_I = FunctionToCallSitesMap.find(F);
142 assert(F2C_I != FunctionToCallSitesMap.end() &&
143 "FunctionToCallSitesMap broken");
144 assert(F2C_I->second.erase(Stub) &&
145 "FunctionToCallSitesMap broken");
146 if (F2C_I->second.empty())
147 FunctionToCallSitesMap.erase(F2C_I);
152 void EraseAllCallSites(const MutexGuard &locked, Function *F) {
153 assert(locked.holds(TheJIT->lock));
154 FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F);
155 if (F2C == FunctionToCallSitesMap.end())
157 for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(),
158 E = F2C->second.end(); I != E; ++I) {
159 assert(CallSiteToFunctionMap.erase(*I) == 1 &&
160 "Missing call site->function mapping");
162 FunctionToCallSitesMap.erase(F2C);
166 /// JITResolver - Keep track of, and resolve, call sites for functions that
167 /// have not yet been compiled.
169 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy;
170 typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy;
171 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
173 /// LazyResolverFn - The target lazy resolver function that we actually
174 /// rewrite instructions to use.
175 TargetJITInfo::LazyResolverFn LazyResolverFn;
177 JITResolverState state;
179 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
180 /// external functions.
181 std::map<void*, void*> ExternalFnToStubMap;
183 /// revGOTMap - map addresses to indexes in the GOT
184 std::map<void*, unsigned> revGOTMap;
185 unsigned nextGOTIndex;
187 static JITResolver *TheJITResolver;
189 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
192 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
193 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
194 TheJITResolver = this;
201 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
202 /// if it has already been created.
203 void *getFunctionStubIfAvailable(Function *F);
205 /// getFunctionStub - This returns a pointer to a function stub, creating
206 /// one on demand as needed. If empty is true, create a function stub
207 /// pointing at address 0, to be filled in later.
208 void *getFunctionStub(Function *F);
210 /// getExternalFunctionStub - Return a stub for the function at the
211 /// specified address, created lazily on demand.
212 void *getExternalFunctionStub(void *FnAddr);
214 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
215 /// specified GV address.
216 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
218 /// AddCallbackAtLocation - If the target is capable of rewriting an
219 /// instruction without the use of a stub, record the location of the use so
220 /// we know which function is being used at the location.
221 void *AddCallbackAtLocation(Function *F, void *Location) {
222 MutexGuard locked(TheJIT->lock);
223 /// Get the target-specific JIT resolver function.
224 state.AddCallSite(locked, Location, F);
225 return (void*)(intptr_t)LazyResolverFn;
228 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
229 SmallVectorImpl<void*> &Ptrs);
231 GlobalValue *invalidateStub(void *Stub);
233 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
234 /// an address. This function only manages slots, it does not manage the
235 /// contents of the slots or the memory associated with the GOT.
236 unsigned getGOTIndexForAddr(void *addr);
238 /// JITCompilerFn - This function is called to resolve a stub to a compiled
239 /// address. If the LLVM Function corresponding to the stub has not yet
240 /// been compiled, this function compiles it first.
241 static void *JITCompilerFn(void *Stub);
245 JITResolver *JITResolver::TheJITResolver = 0;
247 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
248 /// if it has already been created.
249 void *JITResolver::getFunctionStubIfAvailable(Function *F) {
250 MutexGuard locked(TheJIT->lock);
252 // If we already have a stub for this function, recycle it.
253 return state.getFunctionToStubMap(locked).lookup(F);
256 /// getFunctionStub - This returns a pointer to a function stub, creating
257 /// one on demand as needed.
258 void *JITResolver::getFunctionStub(Function *F) {
259 MutexGuard locked(TheJIT->lock);
261 // If we already have a stub for this function, recycle it.
262 void *&Stub = state.getFunctionToStubMap(locked)[F];
263 if (Stub) return Stub;
265 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which
266 // case we must resolve the symbol now.
267 void *Actual = TheJIT->isLazyCompilationDisabled()
268 ? (void *)0 : (void *)(intptr_t)LazyResolverFn;
270 // If this is an external declaration, attempt to resolve the address now
271 // to place in the stub.
272 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
273 Actual = TheJIT->getPointerToFunction(F);
275 // If we resolved the symbol to a null address (eg. a weak external)
276 // don't emit a stub. Return a null pointer to the application. If dlsym
277 // stubs are enabled, not being able to resolve the address is not
279 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
282 // Codegen a new stub, calling the lazy resolver or the actual address of the
283 // external function, if it was resolved.
284 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
285 *TheJIT->getCodeEmitter());
287 if (Actual != (void*)(intptr_t)LazyResolverFn) {
288 // If we are getting the stub for an external function, we really want the
289 // address of the stub in the GlobalAddressMap for the JIT, not the address
290 // of the external function.
291 TheJIT->updateGlobalMapping(F, Stub);
294 DEBUG(errs() << "JIT: Stub emitted at [" << Stub << "] for function '"
295 << F->getName() << "'\n");
297 // Finally, keep track of the stub-to-Function mapping so that the
298 // JITCompilerFn knows which function to compile!
299 state.AddCallSite(locked, Stub, F);
301 // If we are JIT'ing non-lazily but need to call a function that does not
302 // exist yet, add it to the JIT's work list so that we can fill in the stub
304 if (!Actual && TheJIT->isLazyCompilationDisabled())
305 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
306 TheJIT->addPendingFunction(F);
311 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
313 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
314 MutexGuard locked(TheJIT->lock);
316 // If we already have a stub for this global variable, recycle it.
317 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
318 if (IndirectSym) return IndirectSym;
320 // Otherwise, codegen a new indirect symbol.
321 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
322 *TheJIT->getCodeEmitter());
324 DEBUG(errs() << "JIT: Indirect symbol emitted at [" << IndirectSym
325 << "] for GV '" << GV->getName() << "'\n");
330 /// getExternalFunctionStub - Return a stub for the function at the
331 /// specified address, created lazily on demand.
332 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
333 // If we already have a stub for this function, recycle it.
334 void *&Stub = ExternalFnToStubMap[FnAddr];
335 if (Stub) return Stub;
337 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
338 *TheJIT->getCodeEmitter());
340 DEBUG(errs() << "JIT: Stub emitted at [" << Stub
341 << "] for external function at '" << FnAddr << "'\n");
345 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
346 unsigned idx = revGOTMap[addr];
348 idx = ++nextGOTIndex;
349 revGOTMap[addr] = idx;
350 DEBUG(errs() << "JIT: Adding GOT entry " << idx << " for addr ["
356 void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
357 SmallVectorImpl<void*> &Ptrs) {
358 MutexGuard locked(TheJIT->lock);
360 const FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
361 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
363 for (FunctionToStubMapTy::const_iterator i = FM.begin(), e = FM.end();
365 Function *F = i->first;
366 if (F->isDeclaration() && F->hasExternalLinkage()) {
367 GVs.push_back(i->first);
368 Ptrs.push_back(i->second);
371 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
373 GVs.push_back(i->first);
374 Ptrs.push_back(i->second);
378 GlobalValue *JITResolver::invalidateStub(void *Stub) {
379 MutexGuard locked(TheJIT->lock);
381 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
383 // Look up the cheap way first, to see if it's a function stub we are
384 // invalidating. If so, remove it from both the forward and reverse maps.
385 if (Function *F = state.EraseStub(locked, Stub)) {
389 // Otherwise, it might be an indirect symbol stub. Find it and remove it.
390 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
392 if (i->second != Stub)
394 GlobalValue *GV = i->first;
399 // Lastly, check to see if it's in the ExternalFnToStubMap.
400 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
401 e = ExternalFnToStubMap.end(); i != e; ++i) {
402 if (i->second != Stub)
404 ExternalFnToStubMap.erase(i);
411 /// JITCompilerFn - This function is called when a lazy compilation stub has
412 /// been entered. It looks up which function this stub corresponds to, compiles
413 /// it if necessary, then returns the resultant function pointer.
414 void *JITResolver::JITCompilerFn(void *Stub) {
415 JITResolver &JR = *TheJITResolver;
421 // Only lock for getting the Function. The call getPointerToFunction made
422 // in this function might trigger function materializing, which requires
423 // JIT lock to be unlocked.
424 MutexGuard locked(TheJIT->lock);
426 // The address given to us for the stub may not be exactly right, it might
427 // be a little bit after the stub. As such, use upper_bound to find it.
428 pair<void*, Function*> I =
429 JR.state.LookupFunctionFromCallSite(locked, Stub);
434 // If we have already code generated the function, just return the address.
435 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
438 // Otherwise we don't have it, do lazy compilation now.
440 // If lazy compilation is disabled, emit a useful error message and abort.
441 if (TheJIT->isLazyCompilationDisabled()) {
442 llvm_report_error("LLVM JIT requested to do lazy compilation of function '"
443 + F->getName() + "' when lazy compiles are disabled!");
446 DEBUG(errs() << "JIT: Lazily resolving function '" << F->getName()
447 << "' In stub ptr = " << Stub << " actual ptr = "
448 << ActualPtr << "\n");
450 Result = TheJIT->getPointerToFunction(F);
453 // Reacquire the lock to update the GOT map.
454 MutexGuard locked(TheJIT->lock);
456 // We might like to remove the call site from the CallSiteToFunction map, but
457 // we can't do that! Multiple threads could be stuck, waiting to acquire the
458 // lock above. As soon as the 1st function finishes compiling the function,
459 // the next one will be released, and needs to be able to find the function it
462 // FIXME: We could rewrite all references to this stub if we knew them.
464 // What we will do is set the compiled function address to map to the
465 // same GOT entry as the stub so that later clients may update the GOT
466 // if they see it still using the stub address.
467 // Note: this is done so the Resolver doesn't have to manage GOT memory
468 // Do this without allocating map space if the target isn't using a GOT
469 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
470 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
475 //===----------------------------------------------------------------------===//
479 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
480 /// used to output functions to memory for execution.
481 class JITEmitter : public JITCodeEmitter {
482 JITMemoryManager *MemMgr;
484 // When outputting a function stub in the context of some other function, we
485 // save BufferBegin/BufferEnd/CurBufferPtr here.
486 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
488 // When reattempting to JIT a function after running out of space, we store
489 // the estimated size of the function we're trying to JIT here, so we can
490 // ask the memory manager for at least this much space. When we
491 // successfully emit the function, we reset this back to zero.
492 uintptr_t SizeEstimate;
494 /// Relocations - These are the relocations that the function needs, as
496 std::vector<MachineRelocation> Relocations;
498 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
499 /// It is filled in by the StartMachineBasicBlock callback and queried by
500 /// the getMachineBasicBlockAddress callback.
501 std::vector<uintptr_t> MBBLocations;
503 /// ConstantPool - The constant pool for the current function.
505 MachineConstantPool *ConstantPool;
507 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
509 void *ConstantPoolBase;
511 /// ConstPoolAddresses - Addresses of individual constant pool entries.
513 SmallVector<uintptr_t, 8> ConstPoolAddresses;
515 /// JumpTable - The jump tables for the current function.
517 MachineJumpTableInfo *JumpTable;
519 /// JumpTableBase - A pointer to the first entry in the jump table.
523 /// Resolver - This contains info about the currently resolved functions.
524 JITResolver Resolver;
526 /// DE - The dwarf emitter for the jit.
527 OwningPtr<JITDwarfEmitter> DE;
529 /// DR - The debug registerer for the jit.
530 OwningPtr<JITDebugRegisterer> DR;
532 /// LabelLocations - This vector is a mapping from Label ID's to their
534 std::vector<uintptr_t> LabelLocations;
536 /// MMI - Machine module info for exception informations
537 MachineModuleInfo* MMI;
539 // GVSet - a set to keep track of which globals have been seen
540 SmallPtrSet<const GlobalVariable*, 8> GVSet;
542 // CurFn - The llvm function being emitted. Only valid during
544 const Function *CurFn;
546 /// Information about emitted code, which is passed to the
547 /// JITEventListeners. This is reset in startFunction and used in
549 JITEvent_EmittedFunctionDetails EmissionDetails;
551 // CurFnStubUses - For a given Function, a vector of stubs that it
552 // references. This facilitates the JIT detecting that a stub is no
553 // longer used, so that it may be deallocated.
554 DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
556 // StubFnRefs - For a given pointer to a stub, a set of Functions which
557 // reference the stub. When the count of a stub's references drops to zero,
558 // the stub is unused.
559 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
561 // ExtFnStubs - A map of external function names to stubs which have entries
562 // in the JITResolver's ExternalFnToStubMap.
563 StringMap<void *> ExtFnStubs;
565 DebugLocTuple PrevDLT;
568 JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM)
569 : SizeEstimate(0), Resolver(jit), MMI(0), CurFn(0) {
570 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
571 if (jit.getJITInfo().needsGOT()) {
572 MemMgr->AllocateGOT();
573 DEBUG(errs() << "JIT is managing a GOT\n");
576 if (DwarfExceptionHandling || JITEmitDebugInfo) {
577 DE.reset(new JITDwarfEmitter(jit));
579 if (JITEmitDebugInfo) {
580 DR.reset(new JITDebugRegisterer(TM));
587 /// classof - Methods for support type inquiry through isa, cast, and
590 static inline bool classof(const JITEmitter*) { return true; }
591 static inline bool classof(const MachineCodeEmitter*) { return true; }
593 JITResolver &getJITResolver() { return Resolver; }
595 virtual void startFunction(MachineFunction &F);
596 virtual bool finishFunction(MachineFunction &F);
598 void emitConstantPool(MachineConstantPool *MCP);
599 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
600 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
602 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
603 unsigned Alignment = 1);
604 virtual void startGVStub(const GlobalValue* GV, void *Buffer,
606 virtual void* finishGVStub(const GlobalValue *GV);
608 /// allocateSpace - Reserves space in the current block if any, or
609 /// allocate a new one of the given size.
610 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
612 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace,
613 /// this method does not allocate memory in the current output buffer,
614 /// because a global may live longer than the current function.
615 virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment);
617 virtual void addRelocation(const MachineRelocation &MR) {
618 Relocations.push_back(MR);
621 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
622 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
623 MBBLocations.resize((MBB->getNumber()+1)*2);
624 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
625 DEBUG(errs() << "JIT: Emitting BB" << MBB->getNumber() << " at ["
626 << (void*) getCurrentPCValue() << "]\n");
629 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
630 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
632 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
633 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
634 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
635 return MBBLocations[MBB->getNumber()];
638 /// retryWithMoreMemory - Log a retry and deallocate all memory for the
639 /// given function. Increase the minimum allocation size so that we get
640 /// more memory next time.
641 void retryWithMoreMemory(MachineFunction &F);
643 /// deallocateMemForFunction - Deallocate all memory for the specified
645 void deallocateMemForFunction(const Function *F);
647 /// AddStubToCurrentFunction - Mark the current function being JIT'd as
648 /// using the stub at the specified address. Allows
649 /// deallocateMemForFunction to also remove stubs no longer referenced.
650 void AddStubToCurrentFunction(void *Stub);
652 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
653 /// MachineRelocations that reference external functions by name.
654 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
656 virtual void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn);
658 virtual void emitLabel(uint64_t LabelID) {
659 if (LabelLocations.size() <= LabelID)
660 LabelLocations.resize((LabelID+1)*2);
661 LabelLocations[LabelID] = getCurrentPCValue();
664 virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
665 assert(LabelLocations.size() > (unsigned)LabelID &&
666 LabelLocations[LabelID] && "Label not emitted!");
667 return LabelLocations[LabelID];
670 virtual void setModuleInfo(MachineModuleInfo* Info) {
672 if (DE.get()) DE->setModuleInfo(Info);
675 void setMemoryExecutable() {
676 MemMgr->setMemoryExecutable();
679 JITMemoryManager *getMemMgr() const { return MemMgr; }
682 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
683 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
685 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
686 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
687 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
688 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
692 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
693 bool DoesntNeedStub) {
694 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
695 return TheJIT->getOrEmitGlobalVariable(GV);
697 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
698 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
700 // If we have already compiled the function, return a pointer to its body.
701 Function *F = cast<Function>(V);
703 if (!DoesntNeedStub) {
704 // Return the function stub if it's already created.
705 ResultPtr = Resolver.getFunctionStubIfAvailable(F);
707 AddStubToCurrentFunction(ResultPtr);
709 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
711 if (ResultPtr) return ResultPtr;
713 // If this is an external function pointer, we can force the JIT to
714 // 'compile' it, which really just adds it to the map. In dlsym mode,
715 // external functions are forced through a stub, regardless of reloc type.
716 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
717 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
718 return TheJIT->getPointerToFunction(F);
720 // Okay, the function has not been compiled yet, if the target callback
721 // mechanism is capable of rewriting the instruction directly, prefer to do
722 // that instead of emitting a stub. This uses the lazy resolver, so is not
723 // legal if lazy compilation is disabled.
724 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
725 return Resolver.AddCallbackAtLocation(F, Reference);
727 // Otherwise, we have to emit a stub.
728 void *StubAddr = Resolver.getFunctionStub(F);
730 // Add the stub to the current function's list of referenced stubs, so we can
731 // deallocate them if the current function is ever freed. It's possible to
732 // return null from getFunctionStub in the case of a weak extern that fails
735 AddStubToCurrentFunction(StubAddr);
740 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
742 // Make sure GV is emitted first, and create a stub containing the fully
744 void *GVAddress = getPointerToGlobal(V, Reference, true);
745 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
747 // Add the stub to the current function's list of referenced stubs, so we can
748 // deallocate them if the current function is ever freed.
749 AddStubToCurrentFunction(StubAddr);
754 void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
755 assert(CurFn && "Stub added to current function, but current function is 0!");
757 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
758 StubsUsed.push_back(StubAddr);
760 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
761 FnRefs.insert(CurFn);
764 void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
765 if (!DL.isUnknown()) {
766 DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL);
768 if (BeforePrintingInsn) {
769 if (CurDLT.Scope != 0 && PrevDLT != CurDLT) {
770 JITEvent_EmittedFunctionDetails::LineStart NextLine;
771 NextLine.Address = getCurrentPCValue();
773 EmissionDetails.LineStarts.push_back(NextLine);
781 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
782 const TargetData *TD) {
783 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
784 if (Constants.empty()) return 0;
787 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
788 MachineConstantPoolEntry CPE = Constants[i];
789 unsigned AlignMask = CPE.getAlignment() - 1;
790 Size = (Size + AlignMask) & ~AlignMask;
791 const Type *Ty = CPE.getType();
792 Size += TD->getTypeAllocSize(Ty);
797 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
798 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
799 if (JT.empty()) return 0;
801 unsigned NumEntries = 0;
802 for (unsigned i = 0, e = JT.size(); i != e; ++i)
803 NumEntries += JT[i].MBBs.size();
805 unsigned EntrySize = MJTI->getEntrySize();
807 return NumEntries * EntrySize;
810 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
811 if (Alignment == 0) Alignment = 1;
812 // Since we do not know where the buffer will be allocated, be pessimistic.
813 return Size + Alignment;
816 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
817 /// into the running total Size.
819 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
820 const Type *ElTy = GV->getType()->getElementType();
821 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy);
823 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
824 DEBUG(errs() << "JIT: Adding in size " << GVSize << " alignment " << GVAlign);
826 // Assume code section ends with worst possible alignment, so first
827 // variable needs maximal padding.
830 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
835 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
836 /// but are referenced from the constant; put them in GVSet and add their
837 /// size into the running total Size.
839 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
841 // If its undefined, return the garbage.
842 if (isa<UndefValue>(C))
845 // If the value is a ConstantExpr
846 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
847 Constant *Op0 = CE->getOperand(0);
848 switch (CE->getOpcode()) {
849 case Instruction::GetElementPtr:
850 case Instruction::Trunc:
851 case Instruction::ZExt:
852 case Instruction::SExt:
853 case Instruction::FPTrunc:
854 case Instruction::FPExt:
855 case Instruction::UIToFP:
856 case Instruction::SIToFP:
857 case Instruction::FPToUI:
858 case Instruction::FPToSI:
859 case Instruction::PtrToInt:
860 case Instruction::IntToPtr:
861 case Instruction::BitCast: {
862 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
865 case Instruction::Add:
866 case Instruction::FAdd:
867 case Instruction::Sub:
868 case Instruction::FSub:
869 case Instruction::Mul:
870 case Instruction::FMul:
871 case Instruction::UDiv:
872 case Instruction::SDiv:
873 case Instruction::URem:
874 case Instruction::SRem:
875 case Instruction::And:
876 case Instruction::Or:
877 case Instruction::Xor: {
878 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
879 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
884 raw_string_ostream Msg(msg);
885 Msg << "ConstantExpr not handled: " << *CE;
886 llvm_report_error(Msg.str());
891 if (C->getType()->getTypeID() == Type::PointerTyID)
892 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
893 if (GVSet.insert(GV))
894 Size = addSizeOfGlobal(GV, Size);
899 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
900 /// but are referenced from the given initializer.
902 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
904 if (!isa<UndefValue>(Init) &&
905 !isa<ConstantVector>(Init) &&
906 !isa<ConstantAggregateZero>(Init) &&
907 !isa<ConstantArray>(Init) &&
908 !isa<ConstantStruct>(Init) &&
909 Init->getType()->isFirstClassType())
910 Size = addSizeOfGlobalsInConstantVal(Init, Size);
914 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
915 /// globals; then walk the initializers of those globals looking for more.
916 /// If their size has not been considered yet, add it into the running total
919 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
923 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
925 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
927 const TargetInstrDesc &Desc = I->getDesc();
928 const MachineInstr &MI = *I;
929 unsigned NumOps = Desc.getNumOperands();
930 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
931 const MachineOperand &MO = MI.getOperand(CurOp);
933 GlobalValue* V = MO.getGlobal();
934 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
937 // If seen in previous function, it will have an entry here.
938 if (TheJIT->getPointerToGlobalIfAvailable(GV))
940 // If seen earlier in this function, it will have an entry here.
941 // FIXME: it should be possible to combine these tables, by
942 // assuming the addresses of the new globals in this module
943 // start at 0 (or something) and adjusting them after codegen
944 // complete. Another possibility is to grab a marker bit in GV.
945 if (GVSet.insert(GV))
946 // A variable as yet unseen. Add in its size.
947 Size = addSizeOfGlobal(GV, Size);
952 DEBUG(errs() << "JIT: About to look through initializers\n");
953 // Look for more globals that are referenced only from initializers.
954 // GVSet.end is computed each time because the set can grow as we go.
955 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin();
956 I != GVSet.end(); I++) {
957 const GlobalVariable* GV = *I;
958 if (GV->hasInitializer())
959 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
965 void JITEmitter::startFunction(MachineFunction &F) {
966 DEBUG(errs() << "JIT: Starting CodeGen of Function "
967 << F.getFunction()->getName() << "\n");
969 uintptr_t ActualSize = 0;
970 // Set the memory writable, if it's not already
971 MemMgr->setMemoryWritable();
972 if (MemMgr->NeedsExactSize()) {
973 DEBUG(errs() << "JIT: ExactSize\n");
974 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
975 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
976 MachineConstantPool *MCP = F.getConstantPool();
978 // Ensure the constant pool/jump table info is at least 4-byte aligned.
979 ActualSize = RoundUpToAlign(ActualSize, 16);
981 // Add the alignment of the constant pool
982 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment());
984 // Add the constant pool size
985 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
987 // Add the aligment of the jump table info
988 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
990 // Add the jump table size
991 ActualSize += GetJumpTableSizeInBytes(MJTI);
993 // Add the alignment for the function
994 ActualSize = RoundUpToAlign(ActualSize,
995 std::max(F.getFunction()->getAlignment(), 8U));
997 // Add the function size
998 ActualSize += TII->GetFunctionSizeInBytes(F);
1000 DEBUG(errs() << "JIT: ActualSize before globals " << ActualSize << "\n");
1001 // Add the size of the globals that will be allocated after this function.
1002 // These are all the ones referenced from this function that were not
1003 // previously allocated.
1004 ActualSize += GetSizeOfGlobalsInBytes(F);
1005 DEBUG(errs() << "JIT: ActualSize after globals " << ActualSize << "\n");
1006 } else if (SizeEstimate > 0) {
1007 // SizeEstimate will be non-zero on reallocation attempts.
1008 ActualSize = SizeEstimate;
1011 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
1013 BufferEnd = BufferBegin+ActualSize;
1015 // Ensure the constant pool/jump table info is at least 4-byte aligned.
1018 emitConstantPool(F.getConstantPool());
1019 initJumpTableInfo(F.getJumpTableInfo());
1021 // About to start emitting the machine code for the function.
1022 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
1023 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
1025 MBBLocations.clear();
1027 EmissionDetails.MF = &F;
1028 EmissionDetails.LineStarts.clear();
1031 bool JITEmitter::finishFunction(MachineFunction &F) {
1032 if (CurBufferPtr == BufferEnd) {
1033 // We must call endFunctionBody before retrying, because
1034 // deallocateMemForFunction requires it.
1035 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
1036 retryWithMoreMemory(F);
1040 emitJumpTableInfo(F.getJumpTableInfo());
1042 // FnStart is the start of the text, not the start of the constant pool and
1043 // other per-function data.
1045 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
1047 // FnEnd is the end of the function's machine code.
1048 uint8_t *FnEnd = CurBufferPtr;
1050 if (!Relocations.empty()) {
1051 CurFn = F.getFunction();
1052 NumRelos += Relocations.size();
1054 // Resolve the relocations to concrete pointers.
1055 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
1056 MachineRelocation &MR = Relocations[i];
1057 void *ResultPtr = 0;
1058 if (!MR.letTargetResolve()) {
1059 if (MR.isExternalSymbol()) {
1060 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
1062 DEBUG(errs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
1063 << ResultPtr << "]\n");
1065 // If the target REALLY wants a stub for this function, emit it now.
1066 if (!MR.doesntNeedStub()) {
1067 if (!TheJIT->areDlsymStubsEnabled()) {
1068 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
1070 void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
1072 Stub = Resolver.getExternalFunctionStub((void *)&Stub);
1073 AddStubToCurrentFunction(Stub);
1078 } else if (MR.isGlobalValue()) {
1079 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
1080 BufferBegin+MR.getMachineCodeOffset(),
1081 MR.doesntNeedStub());
1082 } else if (MR.isIndirectSymbol()) {
1083 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
1084 BufferBegin+MR.getMachineCodeOffset(),
1085 MR.doesntNeedStub());
1086 } else if (MR.isBasicBlock()) {
1087 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
1088 } else if (MR.isConstantPoolIndex()) {
1089 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
1091 assert(MR.isJumpTableIndex());
1092 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
1095 MR.setResultPointer(ResultPtr);
1098 // if we are managing the GOT and the relocation wants an index,
1100 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
1101 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
1102 MR.setGOTIndex(idx);
1103 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
1104 DEBUG(errs() << "JIT: GOT was out of date for " << ResultPtr
1105 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1107 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
1113 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
1114 Relocations.size(), MemMgr->getGOTBase());
1117 // Update the GOT entry for F to point to the new code.
1118 if (MemMgr->isManagingGOT()) {
1119 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
1120 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
1121 DEBUG(errs() << "JIT: GOT was out of date for " << (void*)BufferBegin
1122 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1124 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
1128 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
1129 // global variables that were referenced in the relocations.
1130 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
1132 if (CurBufferPtr == BufferEnd) {
1133 retryWithMoreMemory(F);
1136 // Now that we've succeeded in emitting the function, reset the
1137 // SizeEstimate back down to zero.
1141 BufferBegin = CurBufferPtr = 0;
1142 NumBytes += FnEnd-FnStart;
1144 // Invalidate the icache if necessary.
1145 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
1147 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
1150 DEBUG(errs() << "JIT: Finished CodeGen of [" << (void*)FnStart
1151 << "] Function: " << F.getFunction()->getName()
1152 << ": " << (FnEnd-FnStart) << " bytes of text, "
1153 << Relocations.size() << " relocations\n");
1155 Relocations.clear();
1156 ConstPoolAddresses.clear();
1158 // Mark code region readable and executable if it's not so already.
1159 MemMgr->setMemoryExecutable();
1162 if (sys::hasDisassembler()) {
1163 errs() << "JIT: Disassembled code:\n";
1164 errs() << sys::disassembleBuffer(FnStart, FnEnd-FnStart,
1165 (uintptr_t)FnStart);
1167 errs() << "JIT: Binary code:\n";
1168 uint8_t* q = FnStart;
1169 for (int i = 0; q < FnEnd; q += 4, ++i) {
1173 errs() << "JIT: " << (long)(q - FnStart) << ": ";
1175 for (int j = 3; j >= 0; --j) {
1179 errs() << (unsigned short)q[j];
1191 if (DwarfExceptionHandling || JITEmitDebugInfo) {
1192 uintptr_t ActualSize = 0;
1193 SavedBufferBegin = BufferBegin;
1194 SavedBufferEnd = BufferEnd;
1195 SavedCurBufferPtr = CurBufferPtr;
1197 if (MemMgr->NeedsExactSize()) {
1198 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
1201 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
1203 BufferEnd = BufferBegin+ActualSize;
1205 uint8_t *FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd,
1207 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
1209 uint8_t *EhEnd = CurBufferPtr;
1210 BufferBegin = SavedBufferBegin;
1211 BufferEnd = SavedBufferEnd;
1212 CurBufferPtr = SavedCurBufferPtr;
1214 if (DwarfExceptionHandling) {
1215 TheJIT->RegisterTable(FrameRegister);
1218 if (JITEmitDebugInfo) {
1220 I.FnStart = FnStart;
1222 I.EhStart = EhStart;
1224 DR->RegisterFunction(F.getFunction(), I);
1234 void JITEmitter::retryWithMoreMemory(MachineFunction &F) {
1235 DEBUG(errs() << "JIT: Ran out of space for native code. Reattempting.\n");
1236 Relocations.clear(); // Clear the old relocations or we'll reapply them.
1237 ConstPoolAddresses.clear();
1239 deallocateMemForFunction(F.getFunction());
1240 // Try again with at least twice as much free space.
1241 SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin));
1244 /// deallocateMemForFunction - Deallocate all memory for the specified
1245 /// function body. Also drop any references the function has to stubs.
1246 void JITEmitter::deallocateMemForFunction(const Function *F) {
1247 MemMgr->deallocateMemForFunction(F);
1249 // TODO: Do we need to unregister exception handling information from libgcc
1252 if (JITEmitDebugInfo) {
1253 DR->UnregisterFunction(F);
1256 // If the function did not reference any stubs, return.
1257 if (CurFnStubUses.find(F) == CurFnStubUses.end())
1260 // For each referenced stub, erase the reference to this function, and then
1261 // erase the list of referenced stubs.
1262 SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
1263 for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
1264 void *Stub = StubList[i];
1266 // If we already invalidated this stub for this function, continue.
1267 if (StubFnRefs.count(Stub) == 0)
1270 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
1273 // If this function was the last reference to the stub, invalidate the stub
1274 // in the JITResolver. Were there a memory manager deallocateStub routine,
1275 // we could call that at this point too.
1276 if (FnRefs.empty()) {
1277 DEBUG(errs() << "\nJIT: Invalidated Stub at [" << Stub << "]\n");
1278 StubFnRefs.erase(Stub);
1280 // Invalidate the stub. If it is a GV stub, update the JIT's global
1281 // mapping for that GV to zero, otherwise, search the string map of
1282 // external function names to stubs and remove the entry for this stub.
1283 GlobalValue *GV = Resolver.invalidateStub(Stub);
1285 TheJIT->updateGlobalMapping(GV, 0);
1287 for (StringMapIterator<void*> i = ExtFnStubs.begin(),
1288 e = ExtFnStubs.end(); i != e; ++i) {
1289 if (i->second == Stub) {
1290 ExtFnStubs.erase(i);
1297 CurFnStubUses.erase(F);
1301 void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1303 return JITCodeEmitter::allocateSpace(Size, Alignment);
1305 // create a new memory block if there is no active one.
1306 // care must be taken so that BufferBegin is invalidated when a
1308 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1309 BufferEnd = BufferBegin+Size;
1310 return CurBufferPtr;
1313 void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
1314 // Delegate this call through the memory manager.
1315 return MemMgr->allocateGlobal(Size, Alignment);
1318 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1319 if (TheJIT->getJITInfo().hasCustomConstantPool())
1322 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1323 if (Constants.empty()) return;
1325 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
1326 unsigned Align = MCP->getConstantPoolAlignment();
1327 ConstantPoolBase = allocateSpace(Size, Align);
1330 if (ConstantPoolBase == 0) return; // Buffer overflow.
1332 DEBUG(errs() << "JIT: Emitted constant pool at [" << ConstantPoolBase
1333 << "] (size: " << Size << ", alignment: " << Align << ")\n");
1335 // Initialize the memory for all of the constant pool entries.
1336 unsigned Offset = 0;
1337 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1338 MachineConstantPoolEntry CPE = Constants[i];
1339 unsigned AlignMask = CPE.getAlignment() - 1;
1340 Offset = (Offset + AlignMask) & ~AlignMask;
1342 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
1343 ConstPoolAddresses.push_back(CAddr);
1344 if (CPE.isMachineConstantPoolEntry()) {
1345 // FIXME: add support to lower machine constant pool values into bytes!
1346 llvm_report_error("Initialize memory with machine specific constant pool"
1347 "entry has not been implemented!");
1349 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
1350 DEBUG(errs() << "JIT: CP" << i << " at [0x";
1351 errs().write_hex(CAddr) << "]\n");
1353 const Type *Ty = CPE.Val.ConstVal->getType();
1354 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty);
1358 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1359 if (TheJIT->getJITInfo().hasCustomJumpTables())
1362 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1363 if (JT.empty()) return;
1365 unsigned NumEntries = 0;
1366 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1367 NumEntries += JT[i].MBBs.size();
1369 unsigned EntrySize = MJTI->getEntrySize();
1371 // Just allocate space for all the jump tables now. We will fix up the actual
1372 // MBB entries in the tables after we emit the code for each block, since then
1373 // we will know the final locations of the MBBs in memory.
1375 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1378 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1379 if (TheJIT->getJITInfo().hasCustomJumpTables())
1382 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1383 if (JT.empty() || JumpTableBase == 0) return;
1385 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1386 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1387 // For each jump table, place the offset from the beginning of the table
1388 // to the target address.
1389 int *SlotPtr = (int*)JumpTableBase;
1391 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1392 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1393 // Store the offset of the basic block for this jump table slot in the
1394 // memory we allocated for the jump table in 'initJumpTableInfo'
1395 uintptr_t Base = (uintptr_t)SlotPtr;
1396 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1397 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1398 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1402 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1404 // For each jump table, map each target in the jump table to the address of
1405 // an emitted MachineBasicBlock.
1406 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1408 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1409 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1410 // Store the address of the basic block for this jump table slot in the
1411 // memory we allocated for the jump table in 'initJumpTableInfo'
1412 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1413 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1418 void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
1419 unsigned Alignment) {
1420 SavedBufferBegin = BufferBegin;
1421 SavedBufferEnd = BufferEnd;
1422 SavedCurBufferPtr = CurBufferPtr;
1424 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1425 BufferEnd = BufferBegin+StubSize+1;
1428 void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
1429 unsigned StubSize) {
1430 SavedBufferBegin = BufferBegin;
1431 SavedBufferEnd = BufferEnd;
1432 SavedCurBufferPtr = CurBufferPtr;
1434 BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
1435 BufferEnd = BufferBegin+StubSize+1;
1438 void *JITEmitter::finishGVStub(const GlobalValue* GV) {
1439 NumBytes += getCurrentPCOffset();
1440 std::swap(SavedBufferBegin, BufferBegin);
1441 BufferEnd = SavedBufferEnd;
1442 CurBufferPtr = SavedCurBufferPtr;
1443 return SavedBufferBegin;
1446 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1447 // in the constant pool that was last emitted with the 'emitConstantPool'
1450 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1451 assert(ConstantNum < ConstantPool->getConstants().size() &&
1452 "Invalid ConstantPoolIndex!");
1453 return ConstPoolAddresses[ConstantNum];
1456 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1457 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1459 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1460 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1461 assert(Index < JT.size() && "Invalid jump table index!");
1463 unsigned Offset = 0;
1464 unsigned EntrySize = JumpTable->getEntrySize();
1466 for (unsigned i = 0; i < Index; ++i)
1467 Offset += JT[i].MBBs.size();
1469 Offset *= EntrySize;
1471 return (uintptr_t)((char *)JumpTableBase + Offset);
1474 //===----------------------------------------------------------------------===//
1475 // Public interface to this file
1476 //===----------------------------------------------------------------------===//
1478 JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM,
1479 TargetMachine &tm) {
1480 return new JITEmitter(jit, JMM, tm);
1483 // getPointerToNamedFunction - This function is used as a global wrapper to
1484 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1485 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1486 // need to resolve function(s) that are being mis-codegenerated, so we need to
1487 // resolve their addresses at runtime, and this is the way to do it.
1489 void *getPointerToNamedFunction(const char *Name) {
1490 if (Function *F = TheJIT->FindFunctionNamed(Name))
1491 return TheJIT->getPointerToFunction(F);
1492 return TheJIT->getPointerToNamedFunction(Name);
1496 // getPointerToFunctionOrStub - If the specified function has been
1497 // code-gen'd, return a pointer to the function. If not, compile it, or use
1498 // a stub to implement lazy compilation if available.
1500 void *JIT::getPointerToFunctionOrStub(Function *F) {
1501 // If we have already code generated the function, just return the address.
1502 if (void *Addr = getPointerToGlobalIfAvailable(F))
1505 // Get a stub if the target supports it.
1506 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1507 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1508 return JE->getJITResolver().getFunctionStub(F);
1511 void JIT::updateFunctionStub(Function *F) {
1512 // Get the empty stub we generated earlier.
1513 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1514 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1515 void *Stub = JE->getJITResolver().getFunctionStub(F);
1517 // Tell the target jit info to rewrite the stub at the specified address,
1518 // rather than creating a new one.
1519 void *Addr = getPointerToGlobalIfAvailable(F);
1520 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
1523 /// updateDlsymStubTable - Emit the data necessary to relocate the stubs
1524 /// that were emitted during code generation.
1526 void JIT::updateDlsymStubTable() {
1527 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1528 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1530 SmallVector<GlobalValue*, 8> GVs;
1531 SmallVector<void*, 8> Ptrs;
1532 const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
1534 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
1536 unsigned nStubs = GVs.size() + ExtFns.size();
1538 // If there are no relocatable stubs, return.
1542 // If there are no new relocatable stubs, return.
1543 void *CurTable = JE->getMemMgr()->getDlsymTable();
1544 if (CurTable && (*(unsigned *)CurTable == nStubs))
1547 // Calculate the size of the stub info
1548 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
1550 SmallVector<unsigned, 8> Offsets;
1551 for (unsigned i = 0; i != GVs.size(); ++i) {
1552 Offsets.push_back(offset);
1553 offset += GVs[i]->getName().size() + 1;
1555 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1557 Offsets.push_back(offset);
1558 offset += strlen(i->first()) + 1;
1561 // Allocate space for the new "stub", which contains the dlsym table.
1562 JE->startGVStub(0, offset, 4);
1564 // Emit the number of records
1565 JE->emitInt32(nStubs);
1567 // Emit the string offsets
1568 for (unsigned i = 0; i != nStubs; ++i)
1569 JE->emitInt32(Offsets[i]);
1571 // Emit the pointers. Verify that they are at least 2-byte aligned, and set
1572 // the low bit to 0 == GV, 1 == Function, so that the client code doing the
1573 // relocation can write the relocated pointer at the appropriate place in
1575 for (unsigned i = 0; i != GVs.size(); ++i) {
1576 intptr_t Ptr = (intptr_t)Ptrs[i];
1577 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
1579 if (isa<Function>(GVs[i]))
1582 if (sizeof(Ptr) == 8)
1587 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1589 intptr_t Ptr = (intptr_t)i->second | 1;
1591 if (sizeof(Ptr) == 8)
1597 // Emit the strings.
1598 for (unsigned i = 0; i != GVs.size(); ++i)
1599 JE->emitString(GVs[i]->getName());
1600 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1602 JE->emitString(i->first());
1604 // Tell the JIT memory manager where it is. The JIT Memory Manager will
1605 // deallocate space for the old one, if one existed.
1606 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
1609 /// freeMachineCodeForFunction - release machine code memory for given Function.
1611 void JIT::freeMachineCodeForFunction(Function *F) {
1613 // Delete translation for this from the ExecutionEngine, so it will get
1614 // retranslated next time it is used.
1615 void *OldPtr = updateGlobalMapping(F, 0);
1618 TheJIT->NotifyFreeingMachineCode(*F, OldPtr);
1620 // Free the actual memory for the function body and related stuff.
1621 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1622 cast<JITEmitter>(JCE)->deallocateMemForFunction(F);