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/Constant.h"
19 #include "llvm/Module.h"
20 #include "llvm/Type.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/Target/TargetData.h"
29 #include "llvm/Target/TargetJITInfo.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/Target/TargetOptions.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/MutexGuard.h"
34 #include "llvm/System/Disassembler.h"
35 #include "llvm/ADT/Statistic.h"
39 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
40 STATISTIC(NumRelos, "Number of relocations applied");
41 static JIT *TheJIT = 0;
44 //===----------------------------------------------------------------------===//
45 // JIT lazy compilation code.
48 class JITResolverState {
50 /// FunctionToStubMap - Keep track of the stub created for a particular
51 /// function so that we can reuse them if necessary.
52 std::map<Function*, void*> FunctionToStubMap;
54 /// StubToFunctionMap - Keep track of the function that each stub
56 std::map<void*, Function*> StubToFunctionMap;
58 /// GlobalToLazyPtrMap - Keep track of the lazy pointer created for a
59 /// particular GlobalVariable so that we can reuse them if necessary.
60 std::map<GlobalValue*, void*> GlobalToLazyPtrMap;
63 std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
64 assert(locked.holds(TheJIT->lock));
65 return FunctionToStubMap;
68 std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
69 assert(locked.holds(TheJIT->lock));
70 return StubToFunctionMap;
73 std::map<GlobalValue*, void*>&
74 getGlobalToLazyPtrMap(const MutexGuard& locked) {
75 assert(locked.holds(TheJIT->lock));
76 return GlobalToLazyPtrMap;
80 /// JITResolver - Keep track of, and resolve, call sites for functions that
81 /// have not yet been compiled.
83 /// LazyResolverFn - The target lazy resolver function that we actually
84 /// rewrite instructions to use.
85 TargetJITInfo::LazyResolverFn LazyResolverFn;
87 JITResolverState state;
89 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
90 /// external functions.
91 std::map<void*, void*> ExternalFnToStubMap;
93 //map addresses to indexes in the GOT
94 std::map<void*, unsigned> revGOTMap;
95 unsigned nextGOTIndex;
97 static JITResolver *TheJITResolver;
99 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
102 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
103 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
104 TheJITResolver = this;
111 /// getFunctionStub - This returns a pointer to a function stub, creating
112 /// one on demand as needed.
113 void *getFunctionStub(Function *F);
115 /// getExternalFunctionStub - Return a stub for the function at the
116 /// specified address, created lazily on demand.
117 void *getExternalFunctionStub(void *FnAddr);
119 /// getGlobalValueLazyPtr - Return a lazy pointer containing the specified
121 void *getGlobalValueLazyPtr(GlobalValue *V, void *GVAddress);
123 /// AddCallbackAtLocation - If the target is capable of rewriting an
124 /// instruction without the use of a stub, record the location of the use so
125 /// we know which function is being used at the location.
126 void *AddCallbackAtLocation(Function *F, void *Location) {
127 MutexGuard locked(TheJIT->lock);
128 /// Get the target-specific JIT resolver function.
129 state.getStubToFunctionMap(locked)[Location] = F;
130 return (void*)(intptr_t)LazyResolverFn;
133 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
134 /// an address. This function only manages slots, it does not manage the
135 /// contents of the slots or the memory associated with the GOT.
136 unsigned getGOTIndexForAddr(void *addr);
138 /// JITCompilerFn - This function is called to resolve a stub to a compiled
139 /// address. If the LLVM Function corresponding to the stub has not yet
140 /// been compiled, this function compiles it first.
141 static void *JITCompilerFn(void *Stub);
145 JITResolver *JITResolver::TheJITResolver = 0;
147 #if (defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)) && \
149 extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
152 /// synchronizeICache - On some targets, the JIT emitted code must be
153 /// explicitly refetched to ensure correct execution.
154 static void synchronizeICache(const void *Addr, size_t len) {
155 #if (defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)) && \
157 sys_icache_invalidate(Addr, len);
161 /// getFunctionStub - This returns a pointer to a function stub, creating
162 /// one on demand as needed.
163 void *JITResolver::getFunctionStub(Function *F) {
164 MutexGuard locked(TheJIT->lock);
166 // If we already have a stub for this function, recycle it.
167 void *&Stub = state.getFunctionToStubMap(locked)[F];
168 if (Stub) return Stub;
170 // Call the lazy resolver function unless we already KNOW it is an external
171 // function, in which case we just skip the lazy resolution step.
172 void *Actual = (void*)(intptr_t)LazyResolverFn;
173 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode())
174 Actual = TheJIT->getPointerToFunction(F);
176 // Otherwise, codegen a new stub. For now, the stub will call the lazy
177 // resolver function.
178 Stub = TheJIT->getJITInfo().emitFunctionStub(Actual,
179 *TheJIT->getCodeEmitter());
181 if (Actual != (void*)(intptr_t)LazyResolverFn) {
182 // If we are getting the stub for an external function, we really want the
183 // address of the stub in the GlobalAddressMap for the JIT, not the address
184 // of the external function.
185 TheJIT->updateGlobalMapping(F, Stub);
188 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
189 << F->getName() << "'\n";
191 // Finally, keep track of the stub-to-Function mapping so that the
192 // JITCompilerFn knows which function to compile!
193 state.getStubToFunctionMap(locked)[Stub] = F;
197 /// getGlobalValueLazyPtr - Return a lazy pointer containing the specified
199 void *JITResolver::getGlobalValueLazyPtr(GlobalValue *GV, void *GVAddress) {
200 MutexGuard locked(TheJIT->lock);
202 // If we already have a stub for this global variable, recycle it.
203 void *&LazyPtr = state.getGlobalToLazyPtrMap(locked)[GV];
204 if (LazyPtr) return LazyPtr;
206 // Otherwise, codegen a new lazy pointer.
207 LazyPtr = TheJIT->getJITInfo().emitGlobalValueLazyPtr(GVAddress,
208 *TheJIT->getCodeEmitter());
210 DOUT << "JIT: Stub emitted at [" << LazyPtr << "] for GV '"
211 << GV->getName() << "'\n";
216 /// getExternalFunctionStub - Return a stub for the function at the
217 /// specified address, created lazily on demand.
218 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
219 // If we already have a stub for this function, recycle it.
220 void *&Stub = ExternalFnToStubMap[FnAddr];
221 if (Stub) return Stub;
223 Stub = TheJIT->getJITInfo().emitFunctionStub(FnAddr,
224 *TheJIT->getCodeEmitter());
226 DOUT << "JIT: Stub emitted at [" << Stub
227 << "] for external function at '" << FnAddr << "'\n";
231 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
232 unsigned idx = revGOTMap[addr];
234 idx = ++nextGOTIndex;
235 revGOTMap[addr] = idx;
236 DOUT << "Adding GOT entry " << idx
237 << " for addr " << addr << "\n";
242 /// JITCompilerFn - This function is called when a lazy compilation stub has
243 /// been entered. It looks up which function this stub corresponds to, compiles
244 /// it if necessary, then returns the resultant function pointer.
245 void *JITResolver::JITCompilerFn(void *Stub) {
246 JITResolver &JR = *TheJITResolver;
248 MutexGuard locked(TheJIT->lock);
250 // The address given to us for the stub may not be exactly right, it might be
251 // a little bit after the stub. As such, use upper_bound to find it.
252 std::map<void*, Function*>::iterator I =
253 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
254 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
255 "This is not a known stub!");
256 Function *F = (--I)->second;
258 // If we have already code generated the function, just return the address.
259 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
262 // Otherwise we don't have it, do lazy compilation now.
264 // If lazy compilation is disabled, emit a useful error message and abort.
265 if (TheJIT->isLazyCompilationDisabled()) {
266 cerr << "LLVM JIT requested to do lazy compilation of function '"
267 << F->getName() << "' when lazy compiles are disabled!\n";
271 // We might like to remove the stub from the StubToFunction map.
272 // We can't do that! Multiple threads could be stuck, waiting to acquire the
273 // lock above. As soon as the 1st function finishes compiling the function,
274 // the next one will be released, and needs to be able to find the function
276 //JR.state.getStubToFunctionMap(locked).erase(I);
278 DOUT << "JIT: Lazily resolving function '" << F->getName()
279 << "' In stub ptr = " << Stub << " actual ptr = "
282 Result = TheJIT->getPointerToFunction(F);
285 // We don't need to reuse this stub in the future, as F is now compiled.
286 JR.state.getFunctionToStubMap(locked).erase(F);
288 // FIXME: We could rewrite all references to this stub if we knew them.
290 // What we will do is set the compiled function address to map to the
291 // same GOT entry as the stub so that later clients may update the GOT
292 // if they see it still using the stub address.
293 // Note: this is done so the Resolver doesn't have to manage GOT memory
294 // Do this without allocating map space if the target isn't using a GOT
295 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
296 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
301 //===----------------------------------------------------------------------===//
302 // Function Index Support
304 // On MacOS we generate an index of currently JIT'd functions so that
305 // performance tools can determine a symbol name and accurate code range for a
306 // PC value. Because performance tools are generally asynchronous, the code
307 // below is written with the hope that it could be interrupted at any time and
308 // have useful answers. However, we don't go crazy with atomic operations, we
309 // just do a "reasonable effort".
311 //#define ENABLE_JIT_SYMBOL_TABLE 1
314 /// JitSymbolEntry - Each function that is JIT compiled results in one of these
315 /// being added to an array of symbols. This indicates the name of the function
316 /// as well as the address range it occupies. This allows the client to map
317 /// from a PC value to the name of the function.
318 struct JitSymbolEntry {
319 const char *FnName; // FnName - a strdup'd string.
325 struct JitSymbolTable {
326 /// NextPtr - This forms a linked list of JitSymbolTable entries. This
327 /// pointer is not used right now, but might be used in the future. Consider
328 /// it reserved for future use.
329 JitSymbolTable *NextPtr;
331 /// Symbols - This is an array of JitSymbolEntry entries. Only the first
332 /// 'NumSymbols' symbols are valid.
333 JitSymbolEntry *Symbols;
335 /// NumSymbols - This indicates the number entries in the Symbols array that
339 /// NumAllocated - This indicates the amount of space we have in the Symbols
340 /// array. This is a private field that should not be read by external tools.
341 unsigned NumAllocated;
344 #if ENABLE_JIT_SYMBOL_TABLE
345 JitSymbolTable *__jitSymbolTable;
348 static void AddFunctionToSymbolTable(const char *FnName,
349 void *FnStart, intptr_t FnSize) {
350 assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
351 JitSymbolTable **SymTabPtrPtr = 0;
352 #if !ENABLE_JIT_SYMBOL_TABLE
355 SymTabPtrPtr = &__jitSymbolTable;
358 // If this is the first entry in the symbol table, add the JitSymbolTable
360 if (*SymTabPtrPtr == 0) {
361 JitSymbolTable *New = new JitSymbolTable();
365 New->NumAllocated = 0;
369 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
371 // If we have space in the table, reallocate the table.
372 if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
373 // If we don't have space, reallocate the table.
374 unsigned NewSize = std::min(64U, SymTabPtr->NumAllocated*2);
375 JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
376 JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
378 // Copy the old entries over.
379 memcpy(NewSymbols, OldSymbols,
380 SymTabPtr->NumAllocated*sizeof(JitSymbolEntry));
382 // Swap the new symbols in, delete the old ones.
383 SymTabPtr->Symbols = NewSymbols;
384 SymTabPtr->NumSymbols = NewSize;
385 delete [] OldSymbols;
388 // Otherwise, we have enough space, just tack it onto the end of the array.
389 JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
390 Entry.FnName = strdup(FnName);
391 Entry.FnStart = FnStart;
392 Entry.FnSize = FnSize;
393 ++SymTabPtr->NumSymbols;
396 static void RemoveFunctionFromSymbolTable(void *FnStart) {
397 assert(FnStart && "Invalid function pointer");
398 JitSymbolTable **SymTabPtrPtr = 0;
399 #if !ENABLE_JIT_SYMBOL_TABLE
402 SymTabPtrPtr = &__jitSymbolTable;
405 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
406 JitSymbolEntry *Symbols = SymTabPtr->Symbols;
408 // Scan the table to find its index. The table is not sorted, so do a linear
411 for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
412 assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
414 // Once we have an index, we know to nuke this entry, overwrite it with the
415 // entry at the end of the array, making the last entry redundant.
416 const char *OldName = Symbols[Index].FnName;
417 Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
418 free((void*)OldName);
420 // Drop the number of symbols in the table.
421 --SymTabPtr->NumSymbols;
423 // Finally, if we deleted the final symbol, deallocate the table itself.
424 if (SymTabPtr->NumSymbols == 0)
432 //===----------------------------------------------------------------------===//
436 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
437 /// used to output functions to memory for execution.
438 class JITEmitter : public MachineCodeEmitter {
439 JITMemoryManager *MemMgr;
441 // When outputting a function stub in the context of some other function, we
442 // save BufferBegin/BufferEnd/CurBufferPtr here.
443 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
445 /// Relocations - These are the relocations that the function needs, as
447 std::vector<MachineRelocation> Relocations;
449 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
450 /// It is filled in by the StartMachineBasicBlock callback and queried by
451 /// the getMachineBasicBlockAddress callback.
452 std::vector<intptr_t> MBBLocations;
454 /// ConstantPool - The constant pool for the current function.
456 MachineConstantPool *ConstantPool;
458 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
460 void *ConstantPoolBase;
462 /// JumpTable - The jump tables for the current function.
464 MachineJumpTableInfo *JumpTable;
466 /// JumpTableBase - A pointer to the first entry in the jump table.
470 /// Resolver - This contains info about the currently resolved functions.
471 JITResolver Resolver;
473 /// DE - The dwarf emitter for the jit.
476 /// LabelLocations - This vector is a mapping from Label ID's to their
478 std::vector<intptr_t> LabelLocations;
480 /// MMI - Machine module info for exception informations
481 MachineModuleInfo* MMI;
484 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit) {
485 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
486 if (jit.getJITInfo().needsGOT()) {
487 MemMgr->AllocateGOT();
488 DOUT << "JIT is managing a GOT\n";
491 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
495 if (ExceptionHandling) delete DE;
498 JITResolver &getJITResolver() { return Resolver; }
500 virtual void startFunction(MachineFunction &F);
501 virtual bool finishFunction(MachineFunction &F);
503 void emitConstantPool(MachineConstantPool *MCP);
504 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
505 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
507 virtual void startFunctionStub(unsigned StubSize, unsigned Alignment = 1);
508 virtual void* finishFunctionStub(const Function *F);
510 virtual void addRelocation(const MachineRelocation &MR) {
511 Relocations.push_back(MR);
514 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
515 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
516 MBBLocations.resize((MBB->getNumber()+1)*2);
517 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
520 virtual intptr_t getConstantPoolEntryAddress(unsigned Entry) const;
521 virtual intptr_t getJumpTableEntryAddress(unsigned Entry) const;
523 virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
524 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
525 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
526 return MBBLocations[MBB->getNumber()];
529 /// deallocateMemForFunction - Deallocate all memory for the specified
531 void deallocateMemForFunction(Function *F) {
532 MemMgr->deallocateMemForFunction(F);
535 virtual void emitLabel(uint64_t LabelID) {
536 if (LabelLocations.size() <= LabelID)
537 LabelLocations.resize((LabelID+1)*2);
538 LabelLocations[LabelID] = getCurrentPCValue();
541 virtual intptr_t getLabelAddress(uint64_t LabelID) const {
542 assert(LabelLocations.size() > (unsigned)LabelID &&
543 LabelLocations[LabelID] && "Label not emitted!");
544 return LabelLocations[LabelID];
547 virtual void setModuleInfo(MachineModuleInfo* Info) {
549 if (ExceptionHandling) DE->setModuleInfo(Info);
553 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
554 void *getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
559 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
560 bool DoesntNeedStub) {
561 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
562 /// FIXME: If we straightened things out, this could actually emit the
563 /// global immediately instead of queuing it for codegen later!
564 return TheJIT->getOrEmitGlobalVariable(GV);
567 // If we have already compiled the function, return a pointer to its body.
568 Function *F = cast<Function>(V);
569 void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
570 if (ResultPtr) return ResultPtr;
572 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
573 // If this is an external function pointer, we can force the JIT to
574 // 'compile' it, which really just adds it to the map.
576 return TheJIT->getPointerToFunction(F);
578 return Resolver.getFunctionStub(F);
581 // Okay, the function has not been compiled yet, if the target callback
582 // mechanism is capable of rewriting the instruction directly, prefer to do
583 // that instead of emitting a stub.
585 return Resolver.AddCallbackAtLocation(F, Reference);
587 // Otherwise, we have to emit a lazy resolving stub.
588 return Resolver.getFunctionStub(F);
591 void *JITEmitter::getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
592 bool DoesntNeedStub) {
593 // Make sure GV is emitted first.
594 // FIXME: For now, if the GV is an external function we force the JIT to
595 // compile it so the lazy pointer will contain the fully resolved address.
596 void *GVAddress = getPointerToGlobal(V, Reference, true);
597 return Resolver.getGlobalValueLazyPtr(V, GVAddress);
601 void JITEmitter::startFunction(MachineFunction &F) {
602 uintptr_t ActualSize;
603 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
605 BufferEnd = BufferBegin+ActualSize;
607 // Ensure the constant pool/jump table info is at least 4-byte aligned.
610 emitConstantPool(F.getConstantPool());
611 initJumpTableInfo(F.getJumpTableInfo());
613 // About to start emitting the machine code for the function.
614 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
615 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
617 MBBLocations.clear();
620 bool JITEmitter::finishFunction(MachineFunction &F) {
621 if (CurBufferPtr == BufferEnd) {
622 // FIXME: Allocate more space, then try again.
623 cerr << "JIT: Ran out of space for generated machine code!\n";
627 emitJumpTableInfo(F.getJumpTableInfo());
629 // FnStart is the start of the text, not the start of the constant pool and
630 // other per-function data.
631 unsigned char *FnStart =
632 (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
633 unsigned char *FnEnd = CurBufferPtr;
635 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
636 NumBytes += FnEnd-FnStart;
638 if (!Relocations.empty()) {
639 NumRelos += Relocations.size();
641 // Resolve the relocations to concrete pointers.
642 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
643 MachineRelocation &MR = Relocations[i];
646 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
648 // If the target REALLY wants a stub for this function, emit it now.
649 if (!MR.doesntNeedStub())
650 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
651 } else if (MR.isGlobalValue()) {
652 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
653 BufferBegin+MR.getMachineCodeOffset(),
654 MR.doesntNeedStub());
655 } else if (MR.isGlobalValueLazyPtr()) {
656 ResultPtr = getPointerToGVLazyPtr(MR.getGlobalValue(),
657 BufferBegin+MR.getMachineCodeOffset(),
658 MR.doesntNeedStub());
659 } else if (MR.isBasicBlock()) {
660 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
661 } else if (MR.isConstantPoolIndex()) {
662 ResultPtr=(void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
664 assert(MR.isJumpTableIndex());
665 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
668 MR.setResultPointer(ResultPtr);
670 // if we are managing the GOT and the relocation wants an index,
672 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
673 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
675 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
676 DOUT << "GOT was out of date for " << ResultPtr
677 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
679 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
684 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
685 Relocations.size(), MemMgr->getGOTBase());
688 // Update the GOT entry for F to point to the new code.
689 if (MemMgr->isManagingGOT()) {
690 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
691 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
692 DOUT << "GOT was out of date for " << (void*)BufferBegin
693 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
694 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
698 // Invalidate the icache if necessary.
699 synchronizeICache(FnStart, FnEnd-FnStart);
701 // Add it to the JIT symbol table if the host wants it.
702 AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
703 FnStart, FnEnd-FnStart);
705 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
706 << "] Function: " << F.getFunction()->getName()
707 << ": " << (FnEnd-FnStart) << " bytes of text, "
708 << Relocations.size() << " relocations\n";
712 if (sys::hasDisassembler())
713 DOUT << "Disassembled code:\n"
714 << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
716 if (ExceptionHandling) {
717 uintptr_t ActualSize;
718 SavedBufferBegin = BufferBegin;
719 SavedBufferEnd = BufferEnd;
720 SavedCurBufferPtr = CurBufferPtr;
722 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
724 BufferEnd = BufferBegin+ActualSize;
725 unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
726 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
728 BufferBegin = SavedBufferBegin;
729 BufferEnd = SavedBufferEnd;
730 CurBufferPtr = SavedCurBufferPtr;
732 TheJIT->RegisterTable(FrameRegister);
739 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
740 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
741 if (Constants.empty()) return;
743 MachineConstantPoolEntry CPE = Constants.back();
744 unsigned Size = CPE.Offset;
745 const Type *Ty = CPE.isMachineConstantPoolEntry()
746 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
747 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
749 ConstantPoolBase = allocateSpace(Size, 1 << MCP->getConstantPoolAlignment());
752 if (ConstantPoolBase == 0) return; // Buffer overflow.
754 // Initialize the memory for all of the constant pool entries.
755 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
756 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
757 if (Constants[i].isMachineConstantPoolEntry()) {
758 // FIXME: add support to lower machine constant pool values into bytes!
759 cerr << "Initialize memory with machine specific constant pool entry"
760 << " has not been implemented!\n";
763 TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
767 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
768 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
769 if (JT.empty()) return;
771 unsigned NumEntries = 0;
772 for (unsigned i = 0, e = JT.size(); i != e; ++i)
773 NumEntries += JT[i].MBBs.size();
775 unsigned EntrySize = MJTI->getEntrySize();
777 // Just allocate space for all the jump tables now. We will fix up the actual
778 // MBB entries in the tables after we emit the code for each block, since then
779 // we will know the final locations of the MBBs in memory.
781 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
784 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
785 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
786 if (JT.empty() || JumpTableBase == 0) return;
788 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
789 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
790 // For each jump table, place the offset from the beginning of the table
791 // to the target address.
792 int *SlotPtr = (int*)JumpTableBase;
794 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
795 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
796 // Store the offset of the basic block for this jump table slot in the
797 // memory we allocated for the jump table in 'initJumpTableInfo'
798 intptr_t Base = (intptr_t)SlotPtr;
799 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
800 intptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
801 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
805 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
807 // For each jump table, map each target in the jump table to the address of
808 // an emitted MachineBasicBlock.
809 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
811 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
812 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
813 // Store the address of the basic block for this jump table slot in the
814 // memory we allocated for the jump table in 'initJumpTableInfo'
815 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
816 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
821 void JITEmitter::startFunctionStub(unsigned StubSize, unsigned Alignment) {
822 SavedBufferBegin = BufferBegin;
823 SavedBufferEnd = BufferEnd;
824 SavedCurBufferPtr = CurBufferPtr;
826 BufferBegin = CurBufferPtr = MemMgr->allocateStub(StubSize, Alignment);
827 BufferEnd = BufferBegin+StubSize+1;
830 void *JITEmitter::finishFunctionStub(const Function *F) {
831 NumBytes += getCurrentPCOffset();
832 std::swap(SavedBufferBegin, BufferBegin);
833 BufferEnd = SavedBufferEnd;
834 CurBufferPtr = SavedCurBufferPtr;
835 return SavedBufferBegin;
838 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
839 // in the constant pool that was last emitted with the 'emitConstantPool'
842 intptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
843 assert(ConstantNum < ConstantPool->getConstants().size() &&
844 "Invalid ConstantPoolIndex!");
845 return (intptr_t)ConstantPoolBase +
846 ConstantPool->getConstants()[ConstantNum].Offset;
849 // getJumpTableEntryAddress - Return the address of the JumpTable with index
850 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
852 intptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
853 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
854 assert(Index < JT.size() && "Invalid jump table index!");
857 unsigned EntrySize = JumpTable->getEntrySize();
859 for (unsigned i = 0; i < Index; ++i)
860 Offset += JT[i].MBBs.size();
864 return (intptr_t)((char *)JumpTableBase + Offset);
867 //===----------------------------------------------------------------------===//
868 // Public interface to this file
869 //===----------------------------------------------------------------------===//
871 MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
872 return new JITEmitter(jit, JMM);
875 // getPointerToNamedFunction - This function is used as a global wrapper to
876 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
877 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
878 // need to resolve function(s) that are being mis-codegenerated, so we need to
879 // resolve their addresses at runtime, and this is the way to do it.
881 void *getPointerToNamedFunction(const char *Name) {
882 if (Function *F = TheJIT->FindFunctionNamed(Name))
883 return TheJIT->getPointerToFunction(F);
884 return TheJIT->getPointerToNamedFunction(Name);
888 // getPointerToFunctionOrStub - If the specified function has been
889 // code-gen'd, return a pointer to the function. If not, compile it, or use
890 // a stub to implement lazy compilation if available.
892 void *JIT::getPointerToFunctionOrStub(Function *F) {
893 // If we have already code generated the function, just return the address.
894 if (void *Addr = getPointerToGlobalIfAvailable(F))
897 // Get a stub if the target supports it.
898 assert(dynamic_cast<JITEmitter*>(MCE) && "Unexpected MCE?");
899 JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
900 return JE->getJITResolver().getFunctionStub(F);
903 /// freeMachineCodeForFunction - release machine code memory for given Function.
905 void JIT::freeMachineCodeForFunction(Function *F) {
907 // Delete translation for this from the ExecutionEngine, so it will get
908 // retranslated next time it is used.
909 void *OldPtr = updateGlobalMapping(F, 0);
912 RemoveFunctionFromSymbolTable(OldPtr);
914 // Free the actual memory for the function body and related stuff.
915 assert(dynamic_cast<JITEmitter*>(MCE) && "Unexpected MCE?");
916 static_cast<JITEmitter*>(MCE)->deallocateMemForFunction(F);