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/MachineCodeEmitter.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/JITMemoryManager.h"
28 #include "llvm/ExecutionEngine/GenericValue.h"
29 #include "llvm/Target/TargetData.h"
30 #include "llvm/Target/TargetJITInfo.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Target/TargetOptions.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/MutexGuard.h"
35 #include "llvm/System/Disassembler.h"
36 #include "llvm/System/Memory.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/ADT/SmallPtrSet.h"
39 #include "llvm/ADT/SmallVector.h"
40 #include "llvm/ADT/Statistic.h"
47 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
48 STATISTIC(NumRelos, "Number of relocations applied");
49 static JIT *TheJIT = 0;
52 //===----------------------------------------------------------------------===//
53 // JIT lazy compilation code.
56 class JITResolverState {
58 /// FunctionToStubMap - Keep track of the stub created for a particular
59 /// function so that we can reuse them if necessary.
60 std::map<Function*, void*> FunctionToStubMap;
62 /// StubToFunctionMap - Keep track of the function that each stub
64 std::map<void*, Function*> StubToFunctionMap;
66 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
67 /// particular GlobalVariable so that we can reuse them if necessary.
68 std::map<GlobalValue*, void*> GlobalToIndirectSymMap;
71 std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
72 assert(locked.holds(TheJIT->lock));
73 return FunctionToStubMap;
76 std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
77 assert(locked.holds(TheJIT->lock));
78 return StubToFunctionMap;
81 std::map<GlobalValue*, void*>&
82 getGlobalToIndirectSymMap(const MutexGuard& locked) {
83 assert(locked.holds(TheJIT->lock));
84 return GlobalToIndirectSymMap;
88 /// JITResolver - Keep track of, and resolve, call sites for functions that
89 /// have not yet been compiled.
91 /// LazyResolverFn - The target lazy resolver function that we actually
92 /// rewrite instructions to use.
93 TargetJITInfo::LazyResolverFn LazyResolverFn;
95 JITResolverState state;
97 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
98 /// external functions.
99 std::map<void*, void*> ExternalFnToStubMap;
101 //map addresses to indexes in the GOT
102 std::map<void*, unsigned> revGOTMap;
103 unsigned nextGOTIndex;
105 static JITResolver *TheJITResolver;
107 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
110 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
111 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
112 TheJITResolver = this;
119 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
120 /// if it has already been created.
121 void *getFunctionStubIfAvailable(Function *F);
123 /// getFunctionStub - This returns a pointer to a function stub, creating
124 /// one on demand as needed. If empty is true, create a function stub
125 /// pointing at address 0, to be filled in later.
126 void *getFunctionStub(Function *F);
128 /// getExternalFunctionStub - Return a stub for the function at the
129 /// specified address, created lazily on demand.
130 void *getExternalFunctionStub(void *FnAddr);
132 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
133 /// specified GV address.
134 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
136 /// AddCallbackAtLocation - If the target is capable of rewriting an
137 /// instruction without the use of a stub, record the location of the use so
138 /// we know which function is being used at the location.
139 void *AddCallbackAtLocation(Function *F, void *Location) {
140 MutexGuard locked(TheJIT->lock);
141 /// Get the target-specific JIT resolver function.
142 state.getStubToFunctionMap(locked)[Location] = F;
143 return (void*)(intptr_t)LazyResolverFn;
146 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
147 SmallVectorImpl<void*> &Ptrs);
149 GlobalValue *invalidateStub(void *Stub);
151 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
152 /// an address. This function only manages slots, it does not manage the
153 /// contents of the slots or the memory associated with the GOT.
154 unsigned getGOTIndexForAddr(void *addr);
156 /// JITCompilerFn - This function is called to resolve a stub to a compiled
157 /// address. If the LLVM Function corresponding to the stub has not yet
158 /// been compiled, this function compiles it first.
159 static void *JITCompilerFn(void *Stub);
163 JITResolver *JITResolver::TheJITResolver = 0;
165 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
166 /// if it has already been created.
167 void *JITResolver::getFunctionStubIfAvailable(Function *F) {
168 MutexGuard locked(TheJIT->lock);
170 // If we already have a stub for this function, recycle it.
171 void *&Stub = state.getFunctionToStubMap(locked)[F];
175 /// getFunctionStub - This returns a pointer to a function stub, creating
176 /// one on demand as needed.
177 void *JITResolver::getFunctionStub(Function *F) {
178 MutexGuard locked(TheJIT->lock);
180 // If we already have a stub for this function, recycle it.
181 void *&Stub = state.getFunctionToStubMap(locked)[F];
182 if (Stub) return Stub;
184 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which
185 // case we must resolve the symbol now.
186 void *Actual = TheJIT->isLazyCompilationDisabled()
187 ? (void *)0 : (void *)(intptr_t)LazyResolverFn;
189 // If this is an external declaration, attempt to resolve the address now
190 // to place in the stub.
191 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
192 Actual = TheJIT->getPointerToFunction(F);
194 // If we resolved the symbol to a null address (eg. a weak external)
195 // don't emit a stub. Return a null pointer to the application. If dlsym
196 // stubs are enabled, not being able to resolve the address is not
198 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
201 // Codegen a new stub, calling the lazy resolver or the actual address of the
202 // external function, if it was resolved.
203 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
204 *TheJIT->getCodeEmitter());
206 if (Actual != (void*)(intptr_t)LazyResolverFn) {
207 // If we are getting the stub for an external function, we really want the
208 // address of the stub in the GlobalAddressMap for the JIT, not the address
209 // of the external function.
210 TheJIT->updateGlobalMapping(F, Stub);
213 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
214 << F->getName() << "'\n";
216 // Finally, keep track of the stub-to-Function mapping so that the
217 // JITCompilerFn knows which function to compile!
218 state.getStubToFunctionMap(locked)[Stub] = F;
220 // If we are JIT'ing non-lazily but need to call a function that does not
221 // exist yet, add it to the JIT's work list so that we can fill in the stub
223 if (!Actual && TheJIT->isLazyCompilationDisabled())
224 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
225 TheJIT->addPendingFunction(F);
230 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
232 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
233 MutexGuard locked(TheJIT->lock);
235 // If we already have a stub for this global variable, recycle it.
236 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
237 if (IndirectSym) return IndirectSym;
239 // Otherwise, codegen a new indirect symbol.
240 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
241 *TheJIT->getCodeEmitter());
243 DOUT << "JIT: Indirect symbol emitted at [" << IndirectSym << "] for GV '"
244 << GV->getName() << "'\n";
249 /// getExternalFunctionStub - Return a stub for the function at the
250 /// specified address, created lazily on demand.
251 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
252 // If we already have a stub for this function, recycle it.
253 void *&Stub = ExternalFnToStubMap[FnAddr];
254 if (Stub) return Stub;
256 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
257 *TheJIT->getCodeEmitter());
259 DOUT << "JIT: Stub emitted at [" << Stub
260 << "] for external function at '" << FnAddr << "'\n";
264 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
265 unsigned idx = revGOTMap[addr];
267 idx = ++nextGOTIndex;
268 revGOTMap[addr] = idx;
269 DOUT << "JIT: Adding GOT entry " << idx << " for addr [" << addr << "]\n";
274 void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
275 SmallVectorImpl<void*> &Ptrs) {
276 MutexGuard locked(TheJIT->lock);
278 std::map<Function*,void*> &FM = state.getFunctionToStubMap(locked);
279 std::map<GlobalValue*,void*> &GM = state.getGlobalToIndirectSymMap(locked);
281 for (std::map<Function*,void*>::iterator i = FM.begin(), e = FM.end();
283 Function *F = i->first;
284 if (F->isDeclaration() && F->hasExternalLinkage()) {
285 GVs.push_back(i->first);
286 Ptrs.push_back(i->second);
289 for (std::map<GlobalValue*,void*>::iterator i = GM.begin(), e = GM.end();
291 GVs.push_back(i->first);
292 Ptrs.push_back(i->second);
296 GlobalValue *JITResolver::invalidateStub(void *Stub) {
297 MutexGuard locked(TheJIT->lock);
299 std::map<Function*,void*> &FM = state.getFunctionToStubMap(locked);
300 std::map<void*,Function*> &SM = state.getStubToFunctionMap(locked);
301 std::map<GlobalValue*,void*> &GM = state.getGlobalToIndirectSymMap(locked);
303 // Look up the cheap way first, to see if it's a function stub we are
304 // invalidating. If so, remove it from both the forward and reverse maps.
305 if (SM.find(Stub) != SM.end()) {
306 Function *F = SM[Stub];
312 // Otherwise, it might be an indirect symbol stub. Find it and remove it.
313 for (std::map<GlobalValue*,void*>::iterator i = GM.begin(), e = GM.end();
315 if (i->second != Stub)
317 GlobalValue *GV = i->first;
322 // Lastly, check to see if it's in the ExternalFnToStubMap.
323 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
324 e = ExternalFnToStubMap.end(); i != e; ++i) {
325 if (i->second != Stub)
327 ExternalFnToStubMap.erase(i);
334 /// JITCompilerFn - This function is called when a lazy compilation stub has
335 /// been entered. It looks up which function this stub corresponds to, compiles
336 /// it if necessary, then returns the resultant function pointer.
337 void *JITResolver::JITCompilerFn(void *Stub) {
338 JITResolver &JR = *TheJITResolver;
344 // Only lock for getting the Function. The call getPointerToFunction made
345 // in this function might trigger function materializing, which requires
346 // JIT lock to be unlocked.
347 MutexGuard locked(TheJIT->lock);
349 // The address given to us for the stub may not be exactly right, it might be
350 // a little bit after the stub. As such, use upper_bound to find it.
351 std::map<void*, Function*>::iterator I =
352 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
353 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
354 "This is not a known stub!");
356 ActualPtr = I->first;
359 // If we have already code generated the function, just return the address.
360 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
363 // Otherwise we don't have it, do lazy compilation now.
365 // If lazy compilation is disabled, emit a useful error message and abort.
366 if (TheJIT->isLazyCompilationDisabled()) {
367 cerr << "LLVM JIT requested to do lazy compilation of function '"
368 << F->getName() << "' when lazy compiles are disabled!\n";
372 // We might like to remove the stub from the StubToFunction map.
373 // We can't do that! Multiple threads could be stuck, waiting to acquire the
374 // lock above. As soon as the 1st function finishes compiling the function,
375 // the next one will be released, and needs to be able to find the function
377 //JR.state.getStubToFunctionMap(locked).erase(I);
379 DOUT << "JIT: Lazily resolving function '" << F->getName()
380 << "' In stub ptr = " << Stub << " actual ptr = "
381 << ActualPtr << "\n";
383 Result = TheJIT->getPointerToFunction(F);
386 // Reacquire the lock to erase the stub in the map.
387 MutexGuard locked(TheJIT->lock);
389 // We don't need to reuse this stub in the future, as F is now compiled.
390 JR.state.getFunctionToStubMap(locked).erase(F);
392 // FIXME: We could rewrite all references to this stub if we knew them.
394 // What we will do is set the compiled function address to map to the
395 // same GOT entry as the stub so that later clients may update the GOT
396 // if they see it still using the stub address.
397 // Note: this is done so the Resolver doesn't have to manage GOT memory
398 // Do this without allocating map space if the target isn't using a GOT
399 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
400 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
405 //===----------------------------------------------------------------------===//
406 // Function Index Support
408 // On MacOS we generate an index of currently JIT'd functions so that
409 // performance tools can determine a symbol name and accurate code range for a
410 // PC value. Because performance tools are generally asynchronous, the code
411 // below is written with the hope that it could be interrupted at any time and
412 // have useful answers. However, we don't go crazy with atomic operations, we
413 // just do a "reasonable effort".
415 #define ENABLE_JIT_SYMBOL_TABLE 0
418 /// JitSymbolEntry - Each function that is JIT compiled results in one of these
419 /// being added to an array of symbols. This indicates the name of the function
420 /// as well as the address range it occupies. This allows the client to map
421 /// from a PC value to the name of the function.
422 struct JitSymbolEntry {
423 const char *FnName; // FnName - a strdup'd string.
429 struct JitSymbolTable {
430 /// NextPtr - This forms a linked list of JitSymbolTable entries. This
431 /// pointer is not used right now, but might be used in the future. Consider
432 /// it reserved for future use.
433 JitSymbolTable *NextPtr;
435 /// Symbols - This is an array of JitSymbolEntry entries. Only the first
436 /// 'NumSymbols' symbols are valid.
437 JitSymbolEntry *Symbols;
439 /// NumSymbols - This indicates the number entries in the Symbols array that
443 /// NumAllocated - This indicates the amount of space we have in the Symbols
444 /// array. This is a private field that should not be read by external tools.
445 unsigned NumAllocated;
448 #if ENABLE_JIT_SYMBOL_TABLE
449 JitSymbolTable *__jitSymbolTable;
452 static void AddFunctionToSymbolTable(const char *FnName,
453 void *FnStart, intptr_t FnSize) {
454 assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
455 JitSymbolTable **SymTabPtrPtr = 0;
456 #if !ENABLE_JIT_SYMBOL_TABLE
459 SymTabPtrPtr = &__jitSymbolTable;
462 // If this is the first entry in the symbol table, add the JitSymbolTable
464 if (*SymTabPtrPtr == 0) {
465 JitSymbolTable *New = new JitSymbolTable();
469 New->NumAllocated = 0;
473 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
475 // If we have space in the table, reallocate the table.
476 if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
477 // If we don't have space, reallocate the table.
478 unsigned NewSize = std::max(64U, SymTabPtr->NumAllocated*2);
479 JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
480 JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
482 // Copy the old entries over.
483 memcpy(NewSymbols, OldSymbols, SymTabPtr->NumSymbols*sizeof(OldSymbols[0]));
485 // Swap the new symbols in, delete the old ones.
486 SymTabPtr->Symbols = NewSymbols;
487 SymTabPtr->NumAllocated = NewSize;
488 delete [] OldSymbols;
491 // Otherwise, we have enough space, just tack it onto the end of the array.
492 JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
493 Entry.FnName = strdup(FnName);
494 Entry.FnStart = FnStart;
495 Entry.FnSize = FnSize;
496 ++SymTabPtr->NumSymbols;
499 static void RemoveFunctionFromSymbolTable(void *FnStart) {
500 assert(FnStart && "Invalid function pointer");
501 JitSymbolTable **SymTabPtrPtr = 0;
502 #if !ENABLE_JIT_SYMBOL_TABLE
505 SymTabPtrPtr = &__jitSymbolTable;
508 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
509 JitSymbolEntry *Symbols = SymTabPtr->Symbols;
511 // Scan the table to find its index. The table is not sorted, so do a linear
514 for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
515 assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
517 // Once we have an index, we know to nuke this entry, overwrite it with the
518 // entry at the end of the array, making the last entry redundant.
519 const char *OldName = Symbols[Index].FnName;
520 Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
521 free((void*)OldName);
523 // Drop the number of symbols in the table.
524 --SymTabPtr->NumSymbols;
526 // Finally, if we deleted the final symbol, deallocate the table itself.
527 if (SymTabPtr->NumSymbols != 0)
535 //===----------------------------------------------------------------------===//
539 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
540 /// used to output functions to memory for execution.
541 class JITEmitter : public MachineCodeEmitter {
542 JITMemoryManager *MemMgr;
544 // When outputting a function stub in the context of some other function, we
545 // save BufferBegin/BufferEnd/CurBufferPtr here.
546 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
548 /// Relocations - These are the relocations that the function needs, as
550 std::vector<MachineRelocation> Relocations;
552 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
553 /// It is filled in by the StartMachineBasicBlock callback and queried by
554 /// the getMachineBasicBlockAddress callback.
555 std::vector<uintptr_t> MBBLocations;
557 /// ConstantPool - The constant pool for the current function.
559 MachineConstantPool *ConstantPool;
561 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
563 void *ConstantPoolBase;
565 /// JumpTable - The jump tables for the current function.
567 MachineJumpTableInfo *JumpTable;
569 /// JumpTableBase - A pointer to the first entry in the jump table.
573 /// Resolver - This contains info about the currently resolved functions.
574 JITResolver Resolver;
576 /// DE - The dwarf emitter for the jit.
579 /// LabelLocations - This vector is a mapping from Label ID's to their
581 std::vector<uintptr_t> LabelLocations;
583 /// MMI - Machine module info for exception informations
584 MachineModuleInfo* MMI;
586 // GVSet - a set to keep track of which globals have been seen
587 SmallPtrSet<const GlobalVariable*, 8> GVSet;
589 // CurFn - The llvm function being emitted. Only valid during
591 const Function *CurFn;
593 // CurFnStubUses - For a given Function, a vector of stubs that it
594 // references. This facilitates the JIT detecting that a stub is no
595 // longer used, so that it may be deallocated.
596 DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
598 // StubFnRefs - For a given pointer to a stub, a set of Functions which
599 // reference the stub. When the count of a stub's references drops to zero,
600 // the stub is unused.
601 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
603 // ExtFnStubs - A map of external function names to stubs which have entries
604 // in the JITResolver's ExternalFnToStubMap.
605 StringMap<void *> ExtFnStubs;
608 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit), CurFn(0) {
609 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
610 if (jit.getJITInfo().needsGOT()) {
611 MemMgr->AllocateGOT();
612 DOUT << "JIT is managing a GOT\n";
615 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
619 if (ExceptionHandling) delete DE;
622 /// classof - Methods for support type inquiry through isa, cast, and
625 static inline bool classof(const JITEmitter*) { return true; }
626 static inline bool classof(const MachineCodeEmitter*) { return true; }
628 JITResolver &getJITResolver() { return Resolver; }
630 virtual void startFunction(MachineFunction &F);
631 virtual bool finishFunction(MachineFunction &F);
633 void emitConstantPool(MachineConstantPool *MCP);
634 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
635 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
637 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
638 unsigned Alignment = 1);
639 virtual void startGVStub(const GlobalValue* GV, void *Buffer,
641 virtual void* finishGVStub(const GlobalValue *GV);
643 /// allocateSpace - Reserves space in the current block if any, or
644 /// allocate a new one of the given size.
645 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
647 virtual void addRelocation(const MachineRelocation &MR) {
648 Relocations.push_back(MR);
651 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
652 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
653 MBBLocations.resize((MBB->getNumber()+1)*2);
654 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
655 DOUT << "JIT: Emitting BB" << MBB->getNumber() << " at ["
656 << (void*) getCurrentPCValue() << "]\n";
659 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
660 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
662 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
663 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
664 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
665 return MBBLocations[MBB->getNumber()];
668 /// deallocateMemForFunction - Deallocate all memory for the specified
670 void deallocateMemForFunction(Function *F);
672 /// AddStubToCurrentFunction - Mark the current function being JIT'd as
673 /// using the stub at the specified address. Allows
674 /// deallocateMemForFunction to also remove stubs no longer referenced.
675 void AddStubToCurrentFunction(void *Stub);
677 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
678 /// MachineRelocations that reference external functions by name.
679 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
681 virtual void emitLabel(uint64_t LabelID) {
682 if (LabelLocations.size() <= LabelID)
683 LabelLocations.resize((LabelID+1)*2);
684 LabelLocations[LabelID] = getCurrentPCValue();
687 virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
688 assert(LabelLocations.size() > (unsigned)LabelID &&
689 LabelLocations[LabelID] && "Label not emitted!");
690 return LabelLocations[LabelID];
693 virtual void setModuleInfo(MachineModuleInfo* Info) {
695 if (ExceptionHandling) DE->setModuleInfo(Info);
698 void setMemoryExecutable(void) {
699 MemMgr->setMemoryExecutable();
702 JITMemoryManager *getMemMgr(void) const { return MemMgr; }
705 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
706 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
708 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
709 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
710 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
711 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
715 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
716 bool DoesntNeedStub) {
717 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
718 return TheJIT->getOrEmitGlobalVariable(GV);
720 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
721 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
723 // If we have already compiled the function, return a pointer to its body.
724 Function *F = cast<Function>(V);
726 if (!DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) {
727 // Return the function stub if it's already created.
728 ResultPtr = Resolver.getFunctionStubIfAvailable(F);
730 AddStubToCurrentFunction(ResultPtr);
732 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
734 if (ResultPtr) return ResultPtr;
736 // If this is an external function pointer, we can force the JIT to
737 // 'compile' it, which really just adds it to the map. In dlsym mode,
738 // external functions are forced through a stub, regardless of reloc type.
739 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
740 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
741 return TheJIT->getPointerToFunction(F);
743 // Okay, the function has not been compiled yet, if the target callback
744 // mechanism is capable of rewriting the instruction directly, prefer to do
745 // that instead of emitting a stub. This uses the lazy resolver, so is not
746 // legal if lazy compilation is disabled.
747 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
748 return Resolver.AddCallbackAtLocation(F, Reference);
750 // Otherwise, we have to emit a stub.
751 void *StubAddr = Resolver.getFunctionStub(F);
753 // Add the stub to the current function's list of referenced stubs, so we can
754 // deallocate them if the current function is ever freed. It's possible to
755 // return null from getFunctionStub in the case of a weak extern that fails
758 AddStubToCurrentFunction(StubAddr);
763 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
765 // Make sure GV is emitted first, and create a stub containing the fully
767 void *GVAddress = getPointerToGlobal(V, Reference, true);
768 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
770 // Add the stub to the current function's list of referenced stubs, so we can
771 // deallocate them if the current function is ever freed.
772 AddStubToCurrentFunction(StubAddr);
777 void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
778 if (!TheJIT->areDlsymStubsEnabled())
781 assert(CurFn && "Stub added to current function, but current function is 0!");
783 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
784 StubsUsed.push_back(StubAddr);
786 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
787 FnRefs.insert(CurFn);
790 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP) {
791 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
792 if (Constants.empty()) return 0;
794 MachineConstantPoolEntry CPE = Constants.back();
795 unsigned Size = CPE.Offset;
796 const Type *Ty = CPE.isMachineConstantPoolEntry()
797 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
798 Size += TheJIT->getTargetData()->getTypePaddedSize(Ty);
802 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
803 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
804 if (JT.empty()) return 0;
806 unsigned NumEntries = 0;
807 for (unsigned i = 0, e = JT.size(); i != e; ++i)
808 NumEntries += JT[i].MBBs.size();
810 unsigned EntrySize = MJTI->getEntrySize();
812 return NumEntries * EntrySize;
815 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
816 if (Alignment == 0) Alignment = 1;
817 // Since we do not know where the buffer will be allocated, be pessimistic.
818 return Size + Alignment;
821 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
822 /// into the running total Size.
824 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
825 const Type *ElTy = GV->getType()->getElementType();
826 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypePaddedSize(ElTy);
828 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
829 DOUT << "JIT: Adding in size " << GVSize << " alignment " << GVAlign;
831 // Assume code section ends with worst possible alignment, so first
832 // variable needs maximal padding.
835 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
840 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
841 /// but are referenced from the constant; put them in GVSet and add their
842 /// size into the running total Size.
844 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
846 // If its undefined, return the garbage.
847 if (isa<UndefValue>(C))
850 // If the value is a ConstantExpr
851 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
852 Constant *Op0 = CE->getOperand(0);
853 switch (CE->getOpcode()) {
854 case Instruction::GetElementPtr:
855 case Instruction::Trunc:
856 case Instruction::ZExt:
857 case Instruction::SExt:
858 case Instruction::FPTrunc:
859 case Instruction::FPExt:
860 case Instruction::UIToFP:
861 case Instruction::SIToFP:
862 case Instruction::FPToUI:
863 case Instruction::FPToSI:
864 case Instruction::PtrToInt:
865 case Instruction::IntToPtr:
866 case Instruction::BitCast: {
867 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
870 case Instruction::Add:
871 case Instruction::Sub:
872 case Instruction::Mul:
873 case Instruction::UDiv:
874 case Instruction::SDiv:
875 case Instruction::URem:
876 case Instruction::SRem:
877 case Instruction::And:
878 case Instruction::Or:
879 case Instruction::Xor: {
880 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
881 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
885 cerr << "ConstantExpr not handled: " << *CE << "\n";
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 DOUT << "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 DOUT << "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 DOUT << "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,
983 1 << MCP->getConstantPoolAlignment());
985 // Add the constant pool size
986 ActualSize += GetConstantPoolSizeInBytes(MCP);
988 // Add the aligment of the jump table info
989 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
991 // Add the jump table size
992 ActualSize += GetJumpTableSizeInBytes(MJTI);
994 // Add the alignment for the function
995 ActualSize = RoundUpToAlign(ActualSize,
996 std::max(F.getFunction()->getAlignment(), 8U));
998 // Add the function size
999 ActualSize += TII->GetFunctionSizeInBytes(F);
1001 DOUT << "JIT: ActualSize before globals " << ActualSize << "\n";
1002 // Add the size of the globals that will be allocated after this function.
1003 // These are all the ones referenced from this function that were not
1004 // previously allocated.
1005 ActualSize += GetSizeOfGlobalsInBytes(F);
1006 DOUT << "JIT: ActualSize after globals " << ActualSize << "\n";
1009 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
1011 BufferEnd = BufferBegin+ActualSize;
1013 // Ensure the constant pool/jump table info is at least 4-byte aligned.
1016 emitConstantPool(F.getConstantPool());
1017 initJumpTableInfo(F.getJumpTableInfo());
1019 // About to start emitting the machine code for the function.
1020 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
1021 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
1023 MBBLocations.clear();
1026 bool JITEmitter::finishFunction(MachineFunction &F) {
1027 if (CurBufferPtr == BufferEnd) {
1028 // FIXME: Allocate more space, then try again.
1029 cerr << "JIT: Ran out of space for generated machine code!\n";
1033 emitJumpTableInfo(F.getJumpTableInfo());
1035 // FnStart is the start of the text, not the start of the constant pool and
1036 // other per-function data.
1037 unsigned char *FnStart =
1038 (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
1040 if (!Relocations.empty()) {
1041 CurFn = F.getFunction();
1042 NumRelos += Relocations.size();
1044 // Resolve the relocations to concrete pointers.
1045 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
1046 MachineRelocation &MR = Relocations[i];
1047 void *ResultPtr = 0;
1048 if (!MR.letTargetResolve()) {
1049 if (MR.isExternalSymbol()) {
1050 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
1052 DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
1053 << ResultPtr << "]\n";
1055 // If the target REALLY wants a stub for this function, emit it now.
1056 if (!MR.doesntNeedStub()) {
1057 if (!TheJIT->areDlsymStubsEnabled()) {
1058 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
1060 void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
1062 Stub = Resolver.getExternalFunctionStub((void *)&Stub);
1063 AddStubToCurrentFunction(Stub);
1068 } else if (MR.isGlobalValue()) {
1069 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
1070 BufferBegin+MR.getMachineCodeOffset(),
1071 MR.doesntNeedStub());
1072 } else if (MR.isIndirectSymbol()) {
1073 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
1074 BufferBegin+MR.getMachineCodeOffset(),
1075 MR.doesntNeedStub());
1076 } else if (MR.isBasicBlock()) {
1077 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
1078 } else if (MR.isConstantPoolIndex()) {
1079 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
1081 assert(MR.isJumpTableIndex());
1082 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
1085 MR.setResultPointer(ResultPtr);
1088 // if we are managing the GOT and the relocation wants an index,
1090 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
1091 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
1092 MR.setGOTIndex(idx);
1093 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
1094 DOUT << "JIT: GOT was out of date for " << ResultPtr
1095 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1097 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
1103 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
1104 Relocations.size(), MemMgr->getGOTBase());
1107 // Update the GOT entry for F to point to the new code.
1108 if (MemMgr->isManagingGOT()) {
1109 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
1110 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
1111 DOUT << "JIT: GOT was out of date for " << (void*)BufferBegin
1112 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
1113 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
1117 unsigned char *FnEnd = CurBufferPtr;
1119 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
1121 if (CurBufferPtr == BufferEnd) {
1122 // FIXME: Allocate more space, then try again.
1123 cerr << "JIT: Ran out of space for generated machine code!\n";
1127 BufferBegin = CurBufferPtr = 0;
1128 NumBytes += FnEnd-FnStart;
1130 // Invalidate the icache if necessary.
1131 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
1133 // Add it to the JIT symbol table if the host wants it.
1134 AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
1135 FnStart, FnEnd-FnStart);
1137 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
1138 << "] Function: " << F.getFunction()->getName()
1139 << ": " << (FnEnd-FnStart) << " bytes of text, "
1140 << Relocations.size() << " relocations\n";
1141 Relocations.clear();
1143 // Mark code region readable and executable if it's not so already.
1144 MemMgr->setMemoryExecutable();
1148 if (sys::hasDisassembler()) {
1149 DOUT << "JIT: Disassembled code:\n";
1150 DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
1152 DOUT << "JIT: Binary code:\n";
1154 unsigned char* q = FnStart;
1155 for (int i = 0; q < FnEnd; q += 4, ++i) {
1159 DOUT << "JIT: " << std::setw(8) << std::setfill('0')
1160 << (long)(q - FnStart) << ": ";
1162 for (int j = 3; j >= 0; --j) {
1166 DOUT << std::setw(2) << std::setfill('0') << (unsigned short)q[j];
1179 if (ExceptionHandling) {
1180 uintptr_t ActualSize = 0;
1181 SavedBufferBegin = BufferBegin;
1182 SavedBufferEnd = BufferEnd;
1183 SavedCurBufferPtr = CurBufferPtr;
1185 if (MemMgr->NeedsExactSize()) {
1186 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
1189 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
1191 BufferEnd = BufferBegin+ActualSize;
1192 unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
1193 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
1195 BufferBegin = SavedBufferBegin;
1196 BufferEnd = SavedBufferEnd;
1197 CurBufferPtr = SavedCurBufferPtr;
1199 TheJIT->RegisterTable(FrameRegister);
1208 /// deallocateMemForFunction - Deallocate all memory for the specified
1209 /// function body. Also drop any references the function has to stubs.
1210 void JITEmitter::deallocateMemForFunction(Function *F) {
1211 MemMgr->deallocateMemForFunction(F);
1213 // If the function did not reference any stubs, return.
1214 if (CurFnStubUses.find(F) == CurFnStubUses.end())
1217 // For each referenced stub, erase the reference to this function, and then
1218 // erase the list of referenced stubs.
1219 SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
1220 for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
1221 void *Stub = StubList[i];
1223 // If we already invalidated this stub for this function, continue.
1224 if (StubFnRefs.count(Stub) == 0)
1227 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
1230 // If this function was the last reference to the stub, invalidate the stub
1231 // in the JITResolver. Were there a memory manager deallocateStub routine,
1232 // we could call that at this point too.
1233 if (FnRefs.empty()) {
1234 DOUT << "\nJIT: Invalidated Stub at [" << Stub << "]\n";
1235 StubFnRefs.erase(Stub);
1237 // Invalidate the stub. If it is a GV stub, update the JIT's global
1238 // mapping for that GV to zero, otherwise, search the string map of
1239 // external function names to stubs and remove the entry for this stub.
1240 GlobalValue *GV = Resolver.invalidateStub(Stub);
1242 TheJIT->updateGlobalMapping(GV, 0);
1244 for (StringMapIterator<void*> i = ExtFnStubs.begin(),
1245 e = ExtFnStubs.end(); i != e; ++i) {
1246 if (i->second == Stub) {
1247 ExtFnStubs.erase(i);
1254 CurFnStubUses.erase(F);
1258 void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1260 return MachineCodeEmitter::allocateSpace(Size, Alignment);
1262 // create a new memory block if there is no active one.
1263 // care must be taken so that BufferBegin is invalidated when a
1265 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1266 BufferEnd = BufferBegin+Size;
1267 return CurBufferPtr;
1270 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1271 if (TheJIT->getJITInfo().hasCustomConstantPool())
1274 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1275 if (Constants.empty()) return;
1277 MachineConstantPoolEntry CPE = Constants.back();
1278 unsigned Size = CPE.Offset;
1279 const Type *Ty = CPE.isMachineConstantPoolEntry()
1280 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
1281 Size += TheJIT->getTargetData()->getTypePaddedSize(Ty);
1283 unsigned Align = 1 << MCP->getConstantPoolAlignment();
1284 ConstantPoolBase = allocateSpace(Size, Align);
1287 if (ConstantPoolBase == 0) return; // Buffer overflow.
1289 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
1290 << "] (size: " << Size << ", alignment: " << Align << ")\n";
1292 // Initialize the memory for all of the constant pool entries.
1293 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1294 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
1295 if (Constants[i].isMachineConstantPoolEntry()) {
1296 // FIXME: add support to lower machine constant pool values into bytes!
1297 cerr << "Initialize memory with machine specific constant pool entry"
1298 << " has not been implemented!\n";
1301 TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
1302 DOUT << "JIT: CP" << i << " at [" << CAddr << "]\n";
1306 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1307 if (TheJIT->getJITInfo().hasCustomJumpTables())
1310 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1311 if (JT.empty()) return;
1313 unsigned NumEntries = 0;
1314 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1315 NumEntries += JT[i].MBBs.size();
1317 unsigned EntrySize = MJTI->getEntrySize();
1319 // Just allocate space for all the jump tables now. We will fix up the actual
1320 // MBB entries in the tables after we emit the code for each block, since then
1321 // we will know the final locations of the MBBs in memory.
1323 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1326 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1327 if (TheJIT->getJITInfo().hasCustomJumpTables())
1330 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1331 if (JT.empty() || JumpTableBase == 0) return;
1333 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1334 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1335 // For each jump table, place the offset from the beginning of the table
1336 // to the target address.
1337 int *SlotPtr = (int*)JumpTableBase;
1339 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1340 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1341 // Store the offset of the basic block for this jump table slot in the
1342 // memory we allocated for the jump table in 'initJumpTableInfo'
1343 uintptr_t Base = (uintptr_t)SlotPtr;
1344 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1345 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1346 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1350 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1352 // For each jump table, map each target in the jump table to the address of
1353 // an emitted MachineBasicBlock.
1354 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1356 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1357 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1358 // Store the address of the basic block for this jump table slot in the
1359 // memory we allocated for the jump table in 'initJumpTableInfo'
1360 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1361 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1366 void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
1367 unsigned Alignment) {
1368 SavedBufferBegin = BufferBegin;
1369 SavedBufferEnd = BufferEnd;
1370 SavedCurBufferPtr = CurBufferPtr;
1372 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1373 BufferEnd = BufferBegin+StubSize+1;
1376 void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
1377 unsigned StubSize) {
1378 SavedBufferBegin = BufferBegin;
1379 SavedBufferEnd = BufferEnd;
1380 SavedCurBufferPtr = CurBufferPtr;
1382 BufferBegin = CurBufferPtr = (unsigned char *)Buffer;
1383 BufferEnd = BufferBegin+StubSize+1;
1386 void *JITEmitter::finishGVStub(const GlobalValue* GV) {
1387 NumBytes += getCurrentPCOffset();
1388 std::swap(SavedBufferBegin, BufferBegin);
1389 BufferEnd = SavedBufferEnd;
1390 CurBufferPtr = SavedCurBufferPtr;
1391 return SavedBufferBegin;
1394 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1395 // in the constant pool that was last emitted with the 'emitConstantPool'
1398 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1399 assert(ConstantNum < ConstantPool->getConstants().size() &&
1400 "Invalid ConstantPoolIndex!");
1401 return (uintptr_t)ConstantPoolBase +
1402 ConstantPool->getConstants()[ConstantNum].Offset;
1405 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1406 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1408 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1409 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1410 assert(Index < JT.size() && "Invalid jump table index!");
1412 unsigned Offset = 0;
1413 unsigned EntrySize = JumpTable->getEntrySize();
1415 for (unsigned i = 0; i < Index; ++i)
1416 Offset += JT[i].MBBs.size();
1418 Offset *= EntrySize;
1420 return (uintptr_t)((char *)JumpTableBase + Offset);
1423 //===----------------------------------------------------------------------===//
1424 // Public interface to this file
1425 //===----------------------------------------------------------------------===//
1427 MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1428 return new JITEmitter(jit, JMM);
1431 // getPointerToNamedFunction - This function is used as a global wrapper to
1432 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1433 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1434 // need to resolve function(s) that are being mis-codegenerated, so we need to
1435 // resolve their addresses at runtime, and this is the way to do it.
1437 void *getPointerToNamedFunction(const char *Name) {
1438 if (Function *F = TheJIT->FindFunctionNamed(Name))
1439 return TheJIT->getPointerToFunction(F);
1440 return TheJIT->getPointerToNamedFunction(Name);
1444 // getPointerToFunctionOrStub - If the specified function has been
1445 // code-gen'd, return a pointer to the function. If not, compile it, or use
1446 // a stub to implement lazy compilation if available.
1448 void *JIT::getPointerToFunctionOrStub(Function *F) {
1449 // If we have already code generated the function, just return the address.
1450 if (void *Addr = getPointerToGlobalIfAvailable(F))
1453 // Get a stub if the target supports it.
1454 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1455 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1456 return JE->getJITResolver().getFunctionStub(F);
1459 void JIT::updateFunctionStub(Function *F) {
1460 // Get the empty stub we generated earlier.
1461 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1462 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1463 void *Stub = JE->getJITResolver().getFunctionStub(F);
1465 // Tell the target jit info to rewrite the stub at the specified address,
1466 // rather than creating a new one.
1467 void *Addr = getPointerToGlobalIfAvailable(F);
1468 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
1471 /// updateDlsymStubTable - Emit the data necessary to relocate the stubs
1472 /// that were emitted during code generation.
1474 void JIT::updateDlsymStubTable() {
1475 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1476 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1478 SmallVector<GlobalValue*, 8> GVs;
1479 SmallVector<void*, 8> Ptrs;
1480 const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
1482 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
1484 unsigned nStubs = GVs.size() + ExtFns.size();
1486 // If there are no relocatable stubs, return.
1490 // If there are no new relocatable stubs, return.
1491 void *CurTable = JE->getMemMgr()->getDlsymTable();
1492 if (CurTable && (*(unsigned *)CurTable == nStubs))
1495 // Calculate the size of the stub info
1496 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
1498 SmallVector<unsigned, 8> Offsets;
1499 for (unsigned i = 0; i != GVs.size(); ++i) {
1500 Offsets.push_back(offset);
1501 offset += GVs[i]->getName().length() + 1;
1503 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1505 Offsets.push_back(offset);
1506 offset += strlen(i->first()) + 1;
1509 // Allocate space for the new "stub", which contains the dlsym table.
1510 JE->startGVStub(0, offset, 4);
1512 // Emit the number of records
1513 MCE->emitInt32(nStubs);
1515 // Emit the string offsets
1516 for (unsigned i = 0; i != nStubs; ++i)
1517 MCE->emitInt32(Offsets[i]);
1519 // Emit the pointers. Verify that they are at least 2-byte aligned, and set
1520 // the low bit to 0 == GV, 1 == Function, so that the client code doing the
1521 // relocation can write the relocated pointer at the appropriate place in
1523 for (unsigned i = 0; i != GVs.size(); ++i) {
1524 intptr_t Ptr = (intptr_t)Ptrs[i];
1525 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
1527 if (isa<Function>(GVs[i]))
1530 if (sizeof(Ptr) == 8)
1531 MCE->emitInt64(Ptr);
1533 MCE->emitInt32(Ptr);
1535 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1537 intptr_t Ptr = (intptr_t)i->second | 1;
1539 if (sizeof(Ptr) == 8)
1540 MCE->emitInt64(Ptr);
1542 MCE->emitInt32(Ptr);
1545 // Emit the strings.
1546 for (unsigned i = 0; i != GVs.size(); ++i)
1547 MCE->emitString(GVs[i]->getName());
1548 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
1550 MCE->emitString(i->first());
1552 // Tell the JIT memory manager where it is. The JIT Memory Manager will
1553 // deallocate space for the old one, if one existed.
1554 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
1557 /// freeMachineCodeForFunction - release machine code memory for given Function.
1559 void JIT::freeMachineCodeForFunction(Function *F) {
1561 // Delete translation for this from the ExecutionEngine, so it will get
1562 // retranslated next time it is used.
1563 void *OldPtr = updateGlobalMapping(F, 0);
1566 RemoveFunctionFromSymbolTable(OldPtr);
1568 // Free the actual memory for the function body and related stuff.
1569 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1570 cast<JITEmitter>(MCE)->deallocateMemForFunction(F);