1 //===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a MachineCodeEmitter object that is used by the JIT to
11 // write machine code to memory and remember where relocatable values are.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "jit"
17 #include "JITDwarfEmitter.h"
18 #include "llvm/Constants.h"
19 #include "llvm/Module.h"
20 #include "llvm/DerivedTypes.h"
21 #include "llvm/CodeGen/JITCodeEmitter.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineConstantPool.h"
24 #include "llvm/CodeGen/MachineJumpTableInfo.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/CodeGen/MachineRelocation.h"
27 #include "llvm/ExecutionEngine/GenericValue.h"
28 #include "llvm/ExecutionEngine/JITEventListener.h"
29 #include "llvm/ExecutionEngine/JITMemoryManager.h"
30 #include "llvm/CodeGen/MachineCodeInfo.h"
31 #include "llvm/Target/TargetData.h"
32 #include "llvm/Target/TargetJITInfo.h"
33 #include "llvm/Target/TargetMachine.h"
34 #include "llvm/Target/TargetOptions.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/ErrorHandling.h"
37 #include "llvm/Support/MutexGuard.h"
38 #include "llvm/Support/ValueHandle.h"
39 #include "llvm/Support/raw_ostream.h"
40 #include "llvm/System/Disassembler.h"
41 #include "llvm/System/Memory.h"
42 #include "llvm/Target/TargetInstrInfo.h"
43 #include "llvm/ADT/SmallPtrSet.h"
44 #include "llvm/ADT/SmallVector.h"
45 #include "llvm/ADT/Statistic.h"
52 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
53 STATISTIC(NumRelos, "Number of relocations applied");
54 static JIT *TheJIT = 0;
57 //===----------------------------------------------------------------------===//
58 // JIT lazy compilation code.
61 class JITResolverState {
63 typedef std::map<AssertingVH<Function>, void*> FunctionToStubMapTy;
64 typedef std::map<void*, Function*> StubToFunctionMapTy;
65 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
67 /// FunctionToStubMap - Keep track of the stub created for a particular
68 /// function so that we can reuse them if necessary.
69 FunctionToStubMapTy FunctionToStubMap;
71 /// StubToFunctionMap - Keep track of the function that each stub
73 StubToFunctionMapTy StubToFunctionMap;
75 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
76 /// particular GlobalVariable so that we can reuse them if necessary.
77 GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
80 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) {
81 assert(locked.holds(TheJIT->lock));
82 return FunctionToStubMap;
85 StubToFunctionMapTy& getStubToFunctionMap(const MutexGuard& locked) {
86 assert(locked.holds(TheJIT->lock));
87 return StubToFunctionMap;
90 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) {
91 assert(locked.holds(TheJIT->lock));
92 return GlobalToIndirectSymMap;
96 /// JITResolver - Keep track of, and resolve, call sites for functions that
97 /// have not yet been compiled.
99 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy;
100 typedef JITResolverState::StubToFunctionMapTy StubToFunctionMapTy;
101 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
103 /// LazyResolverFn - The target lazy resolver function that we actually
104 /// rewrite instructions to use.
105 TargetJITInfo::LazyResolverFn LazyResolverFn;
107 JITResolverState state;
109 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
110 /// external functions.
111 std::map<void*, void*> ExternalFnToStubMap;
113 /// revGOTMap - map addresses to indexes in the GOT
114 std::map<void*, unsigned> revGOTMap;
115 unsigned nextGOTIndex;
117 static JITResolver *TheJITResolver;
119 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
122 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
123 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
124 TheJITResolver = this;
131 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
132 /// if it has already been created.
133 void *getFunctionStubIfAvailable(Function *F);
135 /// getFunctionStub - This returns a pointer to a function stub, creating
136 /// one on demand as needed. If empty is true, create a function stub
137 /// pointing at address 0, to be filled in later.
138 void *getFunctionStub(Function *F);
140 /// getExternalFunctionStub - Return a stub for the function at the
141 /// specified address, created lazily on demand.
142 void *getExternalFunctionStub(void *FnAddr);
144 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
145 /// specified GV address.
146 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
148 /// AddCallbackAtLocation - If the target is capable of rewriting an
149 /// instruction without the use of a stub, record the location of the use so
150 /// we know which function is being used at the location.
151 void *AddCallbackAtLocation(Function *F, void *Location) {
152 MutexGuard locked(TheJIT->lock);
153 /// Get the target-specific JIT resolver function.
154 state.getStubToFunctionMap(locked)[Location] = F;
155 return (void*)(intptr_t)LazyResolverFn;
158 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
159 SmallVectorImpl<void*> &Ptrs);
161 GlobalValue *invalidateStub(void *Stub);
163 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
164 /// an address. This function only manages slots, it does not manage the
165 /// contents of the slots or the memory associated with the GOT.
166 unsigned getGOTIndexForAddr(void *addr);
168 /// JITCompilerFn - This function is called to resolve a stub to a compiled
169 /// address. If the LLVM Function corresponding to the stub has not yet
170 /// been compiled, this function compiles it first.
171 static void *JITCompilerFn(void *Stub);
175 JITResolver *JITResolver::TheJITResolver = 0;
177 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
178 /// if it has already been created.
179 void *JITResolver::getFunctionStubIfAvailable(Function *F) {
180 MutexGuard locked(TheJIT->lock);
182 // If we already have a stub for this function, recycle it.
183 void *&Stub = state.getFunctionToStubMap(locked)[F];
187 /// getFunctionStub - This returns a pointer to a function stub, creating
188 /// one on demand as needed.
189 void *JITResolver::getFunctionStub(Function *F) {
190 MutexGuard locked(TheJIT->lock);
192 // If we already have a stub for this function, recycle it.
193 void *&Stub = state.getFunctionToStubMap(locked)[F];
194 if (Stub) return Stub;
196 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which
197 // case we must resolve the symbol now.
198 void *Actual = TheJIT->isLazyCompilationDisabled()
199 ? (void *)0 : (void *)(intptr_t)LazyResolverFn;
201 // If this is an external declaration, attempt to resolve the address now
202 // to place in the stub.
203 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
204 Actual = TheJIT->getPointerToFunction(F);
206 // If we resolved the symbol to a null address (eg. a weak external)
207 // don't emit a stub. Return a null pointer to the application. If dlsym
208 // stubs are enabled, not being able to resolve the address is not
210 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
213 // Codegen a new stub, calling the lazy resolver or the actual address of the
214 // external function, if it was resolved.
215 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
216 *TheJIT->getCodeEmitter());
218 if (Actual != (void*)(intptr_t)LazyResolverFn) {
219 // If we are getting the stub for an external function, we really want the
220 // address of the stub in the GlobalAddressMap for the JIT, not the address
221 // of the external function.
222 TheJIT->updateGlobalMapping(F, Stub);
225 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
226 << F->getName() << "'\n";
228 // Finally, keep track of the stub-to-Function mapping so that the
229 // JITCompilerFn knows which function to compile!
230 state.getStubToFunctionMap(locked)[Stub] = F;
232 // If we are JIT'ing non-lazily but need to call a function that does not
233 // exist yet, add it to the JIT's work list so that we can fill in the stub
235 if (!Actual && TheJIT->isLazyCompilationDisabled())
236 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
237 TheJIT->addPendingFunction(F);
242 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
244 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
245 MutexGuard locked(TheJIT->lock);
247 // If we already have a stub for this global variable, recycle it.
248 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
249 if (IndirectSym) return IndirectSym;
251 // Otherwise, codegen a new indirect symbol.
252 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
253 *TheJIT->getCodeEmitter());
255 DOUT << "JIT: Indirect symbol emitted at [" << IndirectSym << "] for GV '"
256 << GV->getName() << "'\n";
261 /// getExternalFunctionStub - Return a stub for the function at the
262 /// specified address, created lazily on demand.
263 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
264 // If we already have a stub for this function, recycle it.
265 void *&Stub = ExternalFnToStubMap[FnAddr];
266 if (Stub) return Stub;
268 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
269 *TheJIT->getCodeEmitter());
271 DOUT << "JIT: Stub emitted at [" << Stub
272 << "] for external function at '" << FnAddr << "'\n";
276 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
277 unsigned idx = revGOTMap[addr];
279 idx = ++nextGOTIndex;
280 revGOTMap[addr] = idx;
281 DOUT << "JIT: Adding GOT entry " << idx << " for addr [" << addr << "]\n";
286 void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
287 SmallVectorImpl<void*> &Ptrs) {
288 MutexGuard locked(TheJIT->lock);
290 FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
291 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
293 for (FunctionToStubMapTy::iterator i = FM.begin(), e = FM.end(); i != e; ++i){
294 Function *F = i->first;
295 if (F->isDeclaration() && F->hasExternalLinkage()) {
296 GVs.push_back(i->first);
297 Ptrs.push_back(i->second);
300 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
302 GVs.push_back(i->first);
303 Ptrs.push_back(i->second);
307 GlobalValue *JITResolver::invalidateStub(void *Stub) {
308 MutexGuard locked(TheJIT->lock);
310 FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
311 StubToFunctionMapTy &SM = state.getStubToFunctionMap(locked);
312 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
314 // Look up the cheap way first, to see if it's a function stub we are
315 // invalidating. If so, remove it from both the forward and reverse maps.
316 if (SM.find(Stub) != SM.end()) {
317 Function *F = SM[Stub];
323 // Otherwise, it might be an indirect symbol stub. Find it and remove it.
324 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
326 if (i->second != Stub)
328 GlobalValue *GV = i->first;
333 // Lastly, check to see if it's in the ExternalFnToStubMap.
334 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
335 e = ExternalFnToStubMap.end(); i != e; ++i) {
336 if (i->second != Stub)
338 ExternalFnToStubMap.erase(i);
345 /// JITCompilerFn - This function is called when a lazy compilation stub has
346 /// been entered. It looks up which function this stub corresponds to, compiles
347 /// it if necessary, then returns the resultant function pointer.
348 void *JITResolver::JITCompilerFn(void *Stub) {
349 JITResolver &JR = *TheJITResolver;
355 // Only lock for getting the Function. The call getPointerToFunction made
356 // in this function might trigger function materializing, which requires
357 // JIT lock to be unlocked.
358 MutexGuard locked(TheJIT->lock);
360 // The address given to us for the stub may not be exactly right, it might be
361 // a little bit after the stub. As such, use upper_bound to find it.
362 StubToFunctionMapTy::iterator I =
363 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
364 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
365 "This is not a known stub!");
367 ActualPtr = I->first;
370 // If we have already code generated the function, just return the address.
371 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
374 // Otherwise we don't have it, do lazy compilation now.
376 // If lazy compilation is disabled, emit a useful error message and abort.
377 if (TheJIT->isLazyCompilationDisabled()) {
378 llvm_report_error("LLVM JIT requested to do lazy compilation of function '"
379 + F->getName() + "' when lazy compiles are disabled!");
382 // We might like to remove the stub from the StubToFunction map.
383 // We can't do that! Multiple threads could be stuck, waiting to acquire the
384 // lock above. As soon as the 1st function finishes compiling the function,
385 // the next one will be released, and needs to be able to find the function
387 //JR.state.getStubToFunctionMap(locked).erase(I);
389 DOUT << "JIT: Lazily resolving function '" << F->getName()
390 << "' In stub ptr = " << Stub << " actual ptr = "
391 << ActualPtr << "\n";
393 Result = TheJIT->getPointerToFunction(F);
396 // Reacquire the lock to erase the stub in the map.
397 MutexGuard locked(TheJIT->lock);
399 // We don't need to reuse this stub in the future, as F is now compiled.
400 JR.state.getFunctionToStubMap(locked).erase(F);
402 // FIXME: We could rewrite all references to this stub if we knew them.
404 // What we will do is set the compiled function address to map to the
405 // same GOT entry as the stub so that later clients may update the GOT
406 // if they see it still using the stub address.
407 // Note: this is done so the Resolver doesn't have to manage GOT memory
408 // Do this without allocating map space if the target isn't using a GOT
409 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
410 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
415 //===----------------------------------------------------------------------===//
419 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
420 /// used to output functions to memory for execution.
421 class JITEmitter : public JITCodeEmitter {
422 JITMemoryManager *MemMgr;
424 // When outputting a function stub in the context of some other function, we
425 // save BufferBegin/BufferEnd/CurBufferPtr here.
426 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
428 /// Relocations - These are the relocations that the function needs, as
430 std::vector<MachineRelocation> Relocations;
432 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
433 /// It is filled in by the StartMachineBasicBlock callback and queried by
434 /// the getMachineBasicBlockAddress callback.
435 std::vector<uintptr_t> MBBLocations;
437 /// ConstantPool - The constant pool for the current function.
439 MachineConstantPool *ConstantPool;
441 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
443 void *ConstantPoolBase;
445 /// ConstPoolAddresses - Addresses of individual constant pool entries.
447 SmallVector<uintptr_t, 8> ConstPoolAddresses;
449 /// JumpTable - The jump tables for the current function.
451 MachineJumpTableInfo *JumpTable;
453 /// JumpTableBase - A pointer to the first entry in the jump table.
457 /// Resolver - This contains info about the currently resolved functions.
458 JITResolver Resolver;
460 /// DE - The dwarf emitter for the jit.
463 /// LabelLocations - This vector is a mapping from Label ID's to their
465 std::vector<uintptr_t> LabelLocations;
467 /// MMI - Machine module info for exception informations
468 MachineModuleInfo* MMI;
470 // GVSet - a set to keep track of which globals have been seen
471 SmallPtrSet<const GlobalVariable*, 8> GVSet;
473 // CurFn - The llvm function being emitted. Only valid during
475 const Function *CurFn;
477 /// Information about emitted code, which is passed to the
478 /// JITEventListeners. This is reset in startFunction and used in
480 JITEvent_EmittedFunctionDetails EmissionDetails;
482 // CurFnStubUses - For a given Function, a vector of stubs that it
483 // references. This facilitates the JIT detecting that a stub is no
484 // longer used, so that it may be deallocated.
485 DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
487 // StubFnRefs - For a given pointer to a stub, a set of Functions which
488 // reference the stub. When the count of a stub's references drops to zero,
489 // the stub is unused.
490 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
492 // ExtFnStubs - A map of external function names to stubs which have entries
493 // in the JITResolver's ExternalFnToStubMap.
494 StringMap<void *> ExtFnStubs;
496 DebugLocTuple PrevDLT;
499 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit), CurFn(0) {
500 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
501 if (jit.getJITInfo().needsGOT()) {
502 MemMgr->AllocateGOT();
503 DOUT << "JIT is managing a GOT\n";
506 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
510 if (ExceptionHandling) delete DE;
513 /// classof - Methods for support type inquiry through isa, cast, and
516 static inline bool classof(const JITEmitter*) { return true; }
517 static inline bool classof(const MachineCodeEmitter*) { return true; }
519 JITResolver &getJITResolver() { return Resolver; }
521 virtual void startFunction(MachineFunction &F);
522 virtual bool finishFunction(MachineFunction &F);
524 void emitConstantPool(MachineConstantPool *MCP);
525 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
526 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
528 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
529 unsigned Alignment = 1);
530 virtual void startGVStub(const GlobalValue* GV, void *Buffer,
532 virtual void* finishGVStub(const GlobalValue *GV);
534 /// allocateSpace - Reserves space in the current block if any, or
535 /// allocate a new one of the given size.
536 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
538 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace,
539 /// this method does not allocate memory in the current output buffer,
540 /// because a global may live longer than the current function.
541 virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment);
543 virtual void addRelocation(const MachineRelocation &MR) {
544 Relocations.push_back(MR);
547 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
548 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
549 MBBLocations.resize((MBB->getNumber()+1)*2);
550 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
551 DOUT << "JIT: Emitting BB" << MBB->getNumber() << " at ["
552 << (void*) getCurrentPCValue() << "]\n";
555 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
556 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
558 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
559 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
560 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
561 return MBBLocations[MBB->getNumber()];
564 /// deallocateMemForFunction - Deallocate all memory for the specified
566 void deallocateMemForFunction(Function *F);
568 /// AddStubToCurrentFunction - Mark the current function being JIT'd as
569 /// using the stub at the specified address. Allows
570 /// deallocateMemForFunction to also remove stubs no longer referenced.
571 void AddStubToCurrentFunction(void *Stub);
573 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
574 /// MachineRelocations that reference external functions by name.
575 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
577 virtual void processDebugLoc(DebugLoc DL);
579 virtual void emitLabel(uint64_t LabelID) {
580 if (LabelLocations.size() <= LabelID)
581 LabelLocations.resize((LabelID+1)*2);
582 LabelLocations[LabelID] = getCurrentPCValue();
585 virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
586 assert(LabelLocations.size() > (unsigned)LabelID &&
587 LabelLocations[LabelID] && "Label not emitted!");
588 return LabelLocations[LabelID];
591 virtual void setModuleInfo(MachineModuleInfo* Info) {
593 if (ExceptionHandling) DE->setModuleInfo(Info);
596 void setMemoryExecutable(void) {
597 MemMgr->setMemoryExecutable();
600 JITMemoryManager *getMemMgr(void) const { return MemMgr; }
603 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
604 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
606 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
607 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
608 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
609 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
613 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
614 bool DoesntNeedStub) {
615 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
616 return TheJIT->getOrEmitGlobalVariable(GV);
618 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
619 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
621 // If we have already compiled the function, return a pointer to its body.
622 Function *F = cast<Function>(V);
624 if (!DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) {
625 // Return the function stub if it's already created.
626 ResultPtr = Resolver.getFunctionStubIfAvailable(F);
628 AddStubToCurrentFunction(ResultPtr);
630 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
632 if (ResultPtr) return ResultPtr;
634 // If this is an external function pointer, we can force the JIT to
635 // 'compile' it, which really just adds it to the map. In dlsym mode,
636 // external functions are forced through a stub, regardless of reloc type.
637 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
638 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
639 return TheJIT->getPointerToFunction(F);
641 // Okay, the function has not been compiled yet, if the target callback
642 // mechanism is capable of rewriting the instruction directly, prefer to do
643 // that instead of emitting a stub. This uses the lazy resolver, so is not
644 // legal if lazy compilation is disabled.
645 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
646 return Resolver.AddCallbackAtLocation(F, Reference);
648 // Otherwise, we have to emit a stub.
649 void *StubAddr = Resolver.getFunctionStub(F);
651 // Add the stub to the current function's list of referenced stubs, so we can
652 // deallocate them if the current function is ever freed. It's possible to
653 // return null from getFunctionStub in the case of a weak extern that fails
656 AddStubToCurrentFunction(StubAddr);
661 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
663 // Make sure GV is emitted first, and create a stub containing the fully
665 void *GVAddress = getPointerToGlobal(V, Reference, true);
666 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
668 // Add the stub to the current function's list of referenced stubs, so we can
669 // deallocate them if the current function is ever freed.
670 AddStubToCurrentFunction(StubAddr);
675 void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
676 if (!TheJIT->areDlsymStubsEnabled())
679 assert(CurFn && "Stub added to current function, but current function is 0!");
681 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
682 StubsUsed.push_back(StubAddr);
684 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
685 FnRefs.insert(CurFn);
688 void JITEmitter::processDebugLoc(DebugLoc DL) {
689 if (!DL.isUnknown()) {
690 DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL);
692 if (CurDLT.CompileUnit != 0 && PrevDLT != CurDLT) {
693 JITEvent_EmittedFunctionDetails::LineStart NextLine;
694 NextLine.Address = getCurrentPCValue();
696 EmissionDetails.LineStarts.push_back(NextLine);
703 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
704 const TargetData *TD) {
705 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
706 if (Constants.empty()) return 0;
709 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
710 MachineConstantPoolEntry CPE = Constants[i];
711 unsigned AlignMask = CPE.getAlignment() - 1;
712 Size = (Size + AlignMask) & ~AlignMask;
713 const Type *Ty = CPE.getType();
714 Size += TD->getTypeAllocSize(Ty);
719 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
720 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
721 if (JT.empty()) return 0;
723 unsigned NumEntries = 0;
724 for (unsigned i = 0, e = JT.size(); i != e; ++i)
725 NumEntries += JT[i].MBBs.size();
727 unsigned EntrySize = MJTI->getEntrySize();
729 return NumEntries * EntrySize;
732 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
733 if (Alignment == 0) Alignment = 1;
734 // Since we do not know where the buffer will be allocated, be pessimistic.
735 return Size + Alignment;
738 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
739 /// into the running total Size.
741 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
742 const Type *ElTy = GV->getType()->getElementType();
743 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy);
745 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
746 DOUT << "JIT: Adding in size " << GVSize << " alignment " << GVAlign;
748 // Assume code section ends with worst possible alignment, so first
749 // variable needs maximal padding.
752 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
757 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
758 /// but are referenced from the constant; put them in GVSet and add their
759 /// size into the running total Size.
761 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
763 // If its undefined, return the garbage.
764 if (isa<UndefValue>(C))
767 // If the value is a ConstantExpr
768 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
769 Constant *Op0 = CE->getOperand(0);
770 switch (CE->getOpcode()) {
771 case Instruction::GetElementPtr:
772 case Instruction::Trunc:
773 case Instruction::ZExt:
774 case Instruction::SExt:
775 case Instruction::FPTrunc:
776 case Instruction::FPExt:
777 case Instruction::UIToFP:
778 case Instruction::SIToFP:
779 case Instruction::FPToUI:
780 case Instruction::FPToSI:
781 case Instruction::PtrToInt:
782 case Instruction::IntToPtr:
783 case Instruction::BitCast: {
784 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
787 case Instruction::Add:
788 case Instruction::FAdd:
789 case Instruction::Sub:
790 case Instruction::FSub:
791 case Instruction::Mul:
792 case Instruction::FMul:
793 case Instruction::UDiv:
794 case Instruction::SDiv:
795 case Instruction::URem:
796 case Instruction::SRem:
797 case Instruction::And:
798 case Instruction::Or:
799 case Instruction::Xor: {
800 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
801 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
806 raw_string_ostream Msg(msg);
807 Msg << "ConstantExpr not handled: " << *CE;
808 llvm_report_error(Msg.str());
813 if (C->getType()->getTypeID() == Type::PointerTyID)
814 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
815 if (GVSet.insert(GV))
816 Size = addSizeOfGlobal(GV, Size);
821 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
822 /// but are referenced from the given initializer.
824 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
826 if (!isa<UndefValue>(Init) &&
827 !isa<ConstantVector>(Init) &&
828 !isa<ConstantAggregateZero>(Init) &&
829 !isa<ConstantArray>(Init) &&
830 !isa<ConstantStruct>(Init) &&
831 Init->getType()->isFirstClassType())
832 Size = addSizeOfGlobalsInConstantVal(Init, Size);
836 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
837 /// globals; then walk the initializers of those globals looking for more.
838 /// If their size has not been considered yet, add it into the running total
841 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
845 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
847 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
849 const TargetInstrDesc &Desc = I->getDesc();
850 const MachineInstr &MI = *I;
851 unsigned NumOps = Desc.getNumOperands();
852 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
853 const MachineOperand &MO = MI.getOperand(CurOp);
855 GlobalValue* V = MO.getGlobal();
856 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
859 // If seen in previous function, it will have an entry here.
860 if (TheJIT->getPointerToGlobalIfAvailable(GV))
862 // If seen earlier in this function, it will have an entry here.
863 // FIXME: it should be possible to combine these tables, by
864 // assuming the addresses of the new globals in this module
865 // start at 0 (or something) and adjusting them after codegen
866 // complete. Another possibility is to grab a marker bit in GV.
867 if (GVSet.insert(GV))
868 // A variable as yet unseen. Add in its size.
869 Size = addSizeOfGlobal(GV, Size);
874 DOUT << "JIT: About to look through initializers\n";
875 // Look for more globals that are referenced only from initializers.
876 // GVSet.end is computed each time because the set can grow as we go.
877 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin();
878 I != GVSet.end(); I++) {
879 const GlobalVariable* GV = *I;
880 if (GV->hasInitializer())
881 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
887 void JITEmitter::startFunction(MachineFunction &F) {
888 DOUT << "JIT: Starting CodeGen of Function "
889 << F.getFunction()->getName() << "\n";
891 uintptr_t ActualSize = 0;
892 // Set the memory writable, if it's not already
893 MemMgr->setMemoryWritable();
894 if (MemMgr->NeedsExactSize()) {
895 DOUT << "JIT: ExactSize\n";
896 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
897 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
898 MachineConstantPool *MCP = F.getConstantPool();
900 // Ensure the constant pool/jump table info is at least 4-byte aligned.
901 ActualSize = RoundUpToAlign(ActualSize, 16);
903 // Add the alignment of the constant pool
904 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment());
906 // Add the constant pool size
907 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
909 // Add the aligment of the jump table info
910 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
912 // Add the jump table size
913 ActualSize += GetJumpTableSizeInBytes(MJTI);
915 // Add the alignment for the function
916 ActualSize = RoundUpToAlign(ActualSize,
917 std::max(F.getFunction()->getAlignment(), 8U));
919 // Add the function size
920 ActualSize += TII->GetFunctionSizeInBytes(F);
922 DOUT << "JIT: ActualSize before globals " << ActualSize << "\n";
923 // Add the size of the globals that will be allocated after this function.
924 // These are all the ones referenced from this function that were not
925 // previously allocated.
926 ActualSize += GetSizeOfGlobalsInBytes(F);
927 DOUT << "JIT: ActualSize after globals " << ActualSize << "\n";
930 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
932 BufferEnd = BufferBegin+ActualSize;
934 // Ensure the constant pool/jump table info is at least 4-byte aligned.
937 emitConstantPool(F.getConstantPool());
938 initJumpTableInfo(F.getJumpTableInfo());
940 // About to start emitting the machine code for the function.
941 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
942 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
944 MBBLocations.clear();
946 EmissionDetails.MF = &F;
947 EmissionDetails.LineStarts.clear();
950 bool JITEmitter::finishFunction(MachineFunction &F) {
951 if (CurBufferPtr == BufferEnd) {
952 // FIXME: Allocate more space, then try again.
953 llvm_report_error("JIT: Ran out of space for generated machine code!");
956 emitJumpTableInfo(F.getJumpTableInfo());
958 // FnStart is the start of the text, not the start of the constant pool and
959 // other per-function data.
961 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
963 // FnEnd is the end of the function's machine code.
964 uint8_t *FnEnd = CurBufferPtr;
966 if (!Relocations.empty()) {
967 CurFn = F.getFunction();
968 NumRelos += Relocations.size();
970 // Resolve the relocations to concrete pointers.
971 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
972 MachineRelocation &MR = Relocations[i];
974 if (!MR.letTargetResolve()) {
975 if (MR.isExternalSymbol()) {
976 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
978 DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
979 << ResultPtr << "]\n";
981 // If the target REALLY wants a stub for this function, emit it now.
982 if (!MR.doesntNeedStub()) {
983 if (!TheJIT->areDlsymStubsEnabled()) {
984 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
986 void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
988 Stub = Resolver.getExternalFunctionStub((void *)&Stub);
989 AddStubToCurrentFunction(Stub);
994 } else if (MR.isGlobalValue()) {
995 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
996 BufferBegin+MR.getMachineCodeOffset(),
997 MR.doesntNeedStub());
998 } else if (MR.isIndirectSymbol()) {
999 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
1000 BufferBegin+MR.getMachineCodeOffset(),
1001 MR.doesntNeedStub());
1002 } else if (MR.isBasicBlock()) {
1003 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
1004 } else if (MR.isConstantPoolIndex()) {
1005 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
1007 assert(MR.isJumpTableIndex());
1008 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
1011 MR.setResultPointer(ResultPtr);
1014 // if we are managing the GOT and the relocation wants an index,
1016 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
1017 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
1018 MR.setGOTIndex(idx);
1019 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
1020 DOUT << "JIT: GOT was out of date for " << ResultPtr
1021 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1023 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
1029 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
1030 Relocations.size(), MemMgr->getGOTBase());
1033 // Update the GOT entry for F to point to the new code.
1034 if (MemMgr->isManagingGOT()) {
1035 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
1036 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
1037 DOUT << "JIT: GOT was out of date for " << (void*)BufferBegin
1038 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
1039 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
1043 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
1044 // global variables that were referenced in the relocations.
1045 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
1047 if (CurBufferPtr == BufferEnd) {
1048 // FIXME: Allocate more space, then try again.
1049 llvm_report_error("JIT: Ran out of space for generated machine code!");
1052 BufferBegin = CurBufferPtr = 0;
1053 NumBytes += FnEnd-FnStart;
1055 // Invalidate the icache if necessary.
1056 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
1058 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
1061 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
1062 << "] Function: " << F.getFunction()->getName()
1063 << ": " << (FnEnd-FnStart) << " bytes of text, "
1064 << Relocations.size() << " relocations\n";
1066 Relocations.clear();
1067 ConstPoolAddresses.clear();
1069 // Mark code region readable and executable if it's not so already.
1070 MemMgr->setMemoryExecutable();
1074 if (sys::hasDisassembler()) {
1075 DOUT << "JIT: Disassembled code:\n";
1076 DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
1078 DOUT << "JIT: Binary code:\n";
1080 uint8_t* q = FnStart;
1081 for (int i = 0; q < FnEnd; q += 4, ++i) {
1085 DOUT << "JIT: " << std::setw(8) << std::setfill('0')
1086 << (long)(q - FnStart) << ": ";
1088 for (int j = 3; j >= 0; --j) {
1092 DOUT << std::setw(2) << std::setfill('0') << (unsigned short)q[j];
1105 if (ExceptionHandling) {
1106 uintptr_t ActualSize = 0;
1107 SavedBufferBegin = BufferBegin;
1108 SavedBufferEnd = BufferEnd;
1109 SavedCurBufferPtr = CurBufferPtr;
1111 if (MemMgr->NeedsExactSize()) {
1112 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
1115 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
1117 BufferEnd = BufferBegin+ActualSize;
1118 uint8_t* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
1119 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
1121 BufferBegin = SavedBufferBegin;
1122 BufferEnd = SavedBufferEnd;
1123 CurBufferPtr = SavedCurBufferPtr;
1125 TheJIT->RegisterTable(FrameRegister);
1134 /// deallocateMemForFunction - Deallocate all memory for the specified
1135 /// function body. Also drop any references the function has to stubs.
1136 void JITEmitter::deallocateMemForFunction(Function *F) {
1137 MemMgr->deallocateMemForFunction(F);
1139 // If the function did not reference any stubs, return.
1140 if (CurFnStubUses.find(F) == CurFnStubUses.end())
1143 // For each referenced stub, erase the reference to this function, and then
1144 // erase the list of referenced stubs.
1145 SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
1146 for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
1147 void *Stub = StubList[i];
1149 // If we already invalidated this stub for this function, continue.
1150 if (StubFnRefs.count(Stub) == 0)
1153 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
1156 // If this function was the last reference to the stub, invalidate the stub
1157 // in the JITResolver. Were there a memory manager deallocateStub routine,
1158 // we could call that at this point too.
1159 if (FnRefs.empty()) {
1160 DOUT << "\nJIT: Invalidated Stub at [" << Stub << "]\n";
1161 StubFnRefs.erase(Stub);
1163 // Invalidate the stub. If it is a GV stub, update the JIT's global
1164 // mapping for that GV to zero, otherwise, search the string map of
1165 // external function names to stubs and remove the entry for this stub.
1166 GlobalValue *GV = Resolver.invalidateStub(Stub);
1168 TheJIT->updateGlobalMapping(GV, 0);
1170 for (StringMapIterator<void*> i = ExtFnStubs.begin(),
1171 e = ExtFnStubs.end(); i != e; ++i) {
1172 if (i->second == Stub) {
1173 ExtFnStubs.erase(i);
1180 CurFnStubUses.erase(F);
1184 void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1186 return JITCodeEmitter::allocateSpace(Size, Alignment);
1188 // create a new memory block if there is no active one.
1189 // care must be taken so that BufferBegin is invalidated when a
1191 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1192 BufferEnd = BufferBegin+Size;
1193 return CurBufferPtr;
1196 void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) {
1197 // Delegate this call through the memory manager.
1198 return MemMgr->allocateGlobal(Size, Alignment);
1201 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1202 if (TheJIT->getJITInfo().hasCustomConstantPool())
1205 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1206 if (Constants.empty()) return;
1208 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
1209 unsigned Align = MCP->getConstantPoolAlignment();
1210 ConstantPoolBase = allocateSpace(Size, Align);
1213 if (ConstantPoolBase == 0) return; // Buffer overflow.
1215 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
1216 << "] (size: " << Size << ", alignment: " << Align << ")\n";
1218 // Initialize the memory for all of the constant pool entries.
1219 unsigned Offset = 0;
1220 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1221 MachineConstantPoolEntry CPE = Constants[i];
1222 unsigned AlignMask = CPE.getAlignment() - 1;
1223 Offset = (Offset + AlignMask) & ~AlignMask;
1225 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
1226 ConstPoolAddresses.push_back(CAddr);
1227 if (CPE.isMachineConstantPoolEntry()) {
1228 // FIXME: add support to lower machine constant pool values into bytes!
1229 llvm_report_error("Initialize memory with machine specific constant pool"
1230 "entry has not been implemented!");
1232 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr);
1233 DOUT << "JIT: CP" << i << " at [0x"
1234 << std::hex << CAddr << std::dec << "]\n";
1236 const Type *Ty = CPE.Val.ConstVal->getType();
1237 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty);
1241 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1242 if (TheJIT->getJITInfo().hasCustomJumpTables())
1245 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1246 if (JT.empty()) return;
1248 unsigned NumEntries = 0;
1249 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1250 NumEntries += JT[i].MBBs.size();
1252 unsigned EntrySize = MJTI->getEntrySize();
1254 // Just allocate space for all the jump tables now. We will fix up the actual
1255 // MBB entries in the tables after we emit the code for each block, since then
1256 // we will know the final locations of the MBBs in memory.
1258 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1261 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1262 if (TheJIT->getJITInfo().hasCustomJumpTables())
1265 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1266 if (JT.empty() || JumpTableBase == 0) return;
1268 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1269 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1270 // For each jump table, place the offset from the beginning of the table
1271 // to the target address.
1272 int *SlotPtr = (int*)JumpTableBase;
1274 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1275 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1276 // Store the offset of the basic block for this jump table slot in the
1277 // memory we allocated for the jump table in 'initJumpTableInfo'
1278 uintptr_t Base = (uintptr_t)SlotPtr;
1279 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1280 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1281 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1285 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1287 // For each jump table, map each target in the jump table to the address of
1288 // an emitted MachineBasicBlock.
1289 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1291 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1292 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1293 // Store the address of the basic block for this jump table slot in the
1294 // memory we allocated for the jump table in 'initJumpTableInfo'
1295 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1296 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1301 void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
1302 unsigned Alignment) {
1303 SavedBufferBegin = BufferBegin;
1304 SavedBufferEnd = BufferEnd;
1305 SavedCurBufferPtr = CurBufferPtr;
1307 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1308 BufferEnd = BufferBegin+StubSize+1;
1311 void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
1312 unsigned StubSize) {
1313 SavedBufferBegin = BufferBegin;
1314 SavedBufferEnd = BufferEnd;
1315 SavedCurBufferPtr = CurBufferPtr;
1317 BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
1318 BufferEnd = BufferBegin+StubSize+1;
1321 void *JITEmitter::finishGVStub(const GlobalValue* GV) {
1322 NumBytes += getCurrentPCOffset();
1323 std::swap(SavedBufferBegin, BufferBegin);
1324 BufferEnd = SavedBufferEnd;
1325 CurBufferPtr = SavedCurBufferPtr;
1326 return SavedBufferBegin;
1329 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1330 // in the constant pool that was last emitted with the 'emitConstantPool'
1333 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1334 assert(ConstantNum < ConstantPool->getConstants().size() &&
1335 "Invalid ConstantPoolIndex!");
1336 return ConstPoolAddresses[ConstantNum];
1339 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1340 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1342 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1343 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1344 assert(Index < JT.size() && "Invalid jump table index!");
1346 unsigned Offset = 0;
1347 unsigned EntrySize = JumpTable->getEntrySize();
1349 for (unsigned i = 0; i < Index; ++i)
1350 Offset += JT[i].MBBs.size();
1352 Offset *= EntrySize;
1354 return (uintptr_t)((char *)JumpTableBase + Offset);
1357 //===----------------------------------------------------------------------===//
1358 // Public interface to this file
1359 //===----------------------------------------------------------------------===//
1361 JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1362 return new JITEmitter(jit, JMM);
1365 // getPointerToNamedFunction - This function is used as a global wrapper to
1366 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1367 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1368 // need to resolve function(s) that are being mis-codegenerated, so we need to
1369 // resolve their addresses at runtime, and this is the way to do it.
1371 void *getPointerToNamedFunction(const char *Name) {
1372 if (Function *F = TheJIT->FindFunctionNamed(Name))
1373 return TheJIT->getPointerToFunction(F);
1374 return TheJIT->getPointerToNamedFunction(Name);
1378 // getPointerToFunctionOrStub - If the specified function has been
1379 // code-gen'd, return a pointer to the function. If not, compile it, or use
1380 // a stub to implement lazy compilation if available.
1382 void *JIT::getPointerToFunctionOrStub(Function *F) {
1383 // If we have already code generated the function, just return the address.
1384 if (void *Addr = getPointerToGlobalIfAvailable(F))
1387 // Get a stub if the target supports it.
1388 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1389 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1390 return JE->getJITResolver().getFunctionStub(F);
1393 void JIT::updateFunctionStub(Function *F) {
1394 // Get the empty stub we generated earlier.
1395 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1396 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1397 void *Stub = JE->getJITResolver().getFunctionStub(F);
1399 // Tell the target jit info to rewrite the stub at the specified address,
1400 // rather than creating a new one.
1401 void *Addr = getPointerToGlobalIfAvailable(F);
1402 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
1405 /// updateDlsymStubTable - Emit the data necessary to relocate the stubs
1406 /// that were emitted during code generation.
1408 void JIT::updateDlsymStubTable() {
1409 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1410 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1412 SmallVector<GlobalValue*, 8> GVs;
1413 SmallVector<void*, 8> Ptrs;
1414 const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
1416 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
1418 unsigned nStubs = GVs.size() + ExtFns.size();
1420 // If there are no relocatable stubs, return.
1424 // If there are no new relocatable stubs, return.
1425 void *CurTable = JE->getMemMgr()->getDlsymTable();
1426 if (CurTable && (*(unsigned *)CurTable == nStubs))
1429 // Calculate the size of the stub info
1430 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
1432 SmallVector<unsigned, 8> Offsets;
1433 for (unsigned i = 0; i != GVs.size(); ++i) {
1434 Offsets.push_back(offset);
1435 offset += GVs[i]->getName().size() + 1;
1437 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1439 Offsets.push_back(offset);
1440 offset += strlen(i->first()) + 1;
1443 // Allocate space for the new "stub", which contains the dlsym table.
1444 JE->startGVStub(0, offset, 4);
1446 // Emit the number of records
1447 JE->emitInt32(nStubs);
1449 // Emit the string offsets
1450 for (unsigned i = 0; i != nStubs; ++i)
1451 JE->emitInt32(Offsets[i]);
1453 // Emit the pointers. Verify that they are at least 2-byte aligned, and set
1454 // the low bit to 0 == GV, 1 == Function, so that the client code doing the
1455 // relocation can write the relocated pointer at the appropriate place in
1457 for (unsigned i = 0; i != GVs.size(); ++i) {
1458 intptr_t Ptr = (intptr_t)Ptrs[i];
1459 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
1461 if (isa<Function>(GVs[i]))
1464 if (sizeof(Ptr) == 8)
1469 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1471 intptr_t Ptr = (intptr_t)i->second | 1;
1473 if (sizeof(Ptr) == 8)
1479 // Emit the strings.
1480 for (unsigned i = 0; i != GVs.size(); ++i)
1481 JE->emitString(GVs[i]->getName());
1482 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1484 JE->emitString(i->first());
1486 // Tell the JIT memory manager where it is. The JIT Memory Manager will
1487 // deallocate space for the old one, if one existed.
1488 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
1491 /// freeMachineCodeForFunction - release machine code memory for given Function.
1493 void JIT::freeMachineCodeForFunction(Function *F) {
1495 // Delete translation for this from the ExecutionEngine, so it will get
1496 // retranslated next time it is used.
1497 void *OldPtr = updateGlobalMapping(F, 0);
1500 TheJIT->NotifyFreeingMachineCode(*F, OldPtr);
1502 // Free the actual memory for the function body and related stuff.
1503 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
1504 cast<JITEmitter>(JCE)->deallocateMemForFunction(F);