1 //===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
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 tool implements a just-in-time compiler for LLVM, allowing direct
11 // execution of LLVM bitcode in an efficient manner.
13 //===----------------------------------------------------------------------===//
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Function.h"
19 #include "llvm/GlobalVariable.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/CodeGen/JITCodeEmitter.h"
23 #include "llvm/CodeGen/MachineCodeInfo.h"
24 #include "llvm/ExecutionEngine/GenericValue.h"
25 #include "llvm/ExecutionEngine/JITEventListener.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/Target/TargetMachine.h"
28 #include "llvm/Target/TargetJITInfo.h"
29 #include "llvm/Support/Dwarf.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/ManagedStatic.h"
32 #include "llvm/Support/MutexGuard.h"
33 #include "llvm/Support/DynamicLibrary.h"
34 #include "llvm/Config/config.h"
39 // Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
40 // of atexit). It passes the address of linker generated symbol __dso_handle
42 // This configuration change happened at version 5330.
43 # include <AvailabilityMacros.h>
44 # if defined(MAC_OS_X_VERSION_10_4) && \
45 ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
46 (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
47 __APPLE_CC__ >= 5330))
48 # ifndef HAVE___DSO_HANDLE
49 # define HAVE___DSO_HANDLE 1
55 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
60 static struct RegisterJIT {
61 RegisterJIT() { JIT::Register(); }
66 extern "C" void LLVMLinkInJIT() {
69 // Determine whether we can register EH tables.
70 #if (defined(__GNUC__) && !defined(__ARM_EABI__) && \
71 !defined(__USING_SJLJ_EXCEPTIONS__))
72 #define HAVE_EHTABLE_SUPPORT 1
74 #define HAVE_EHTABLE_SUPPORT 0
77 #if HAVE_EHTABLE_SUPPORT
79 // libgcc defines the __register_frame function to dynamically register new
80 // dwarf frames for exception handling. This functionality is not portable
81 // across compilers and is only provided by GCC. We use the __register_frame
82 // function here so that code generated by the JIT cooperates with the unwinding
83 // runtime of libgcc. When JITting with exception handling enable, LLVM
84 // generates dwarf frames and registers it to libgcc with __register_frame.
86 // The __register_frame function works with Linux.
88 // Unfortunately, this functionality seems to be in libgcc after the unwinding
89 // library of libgcc for darwin was written. The code for darwin overwrites the
90 // value updated by __register_frame with a value fetched with "keymgr".
91 // "keymgr" is an obsolete functionality, which should be rewritten some day.
92 // In the meantime, since "keymgr" is on all libgccs shipped with apple-gcc, we
93 // need a workaround in LLVM which uses the "keymgr" to dynamically modify the
94 // values of an opaque key, used by libgcc to find dwarf tables.
96 extern "C" void __register_frame(void*);
97 extern "C" void __deregister_frame(void*);
99 #if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED <= 1050
100 # define USE_KEYMGR 1
102 # define USE_KEYMGR 0
109 // LibgccObject - This is the structure defined in libgcc. There is no #include
110 // provided for this structure, so we also define it here. libgcc calls it
111 // "struct object". The structure is undocumented in libgcc.
112 struct LibgccObject {
117 /// frame - Pointer to the exception table.
120 /// encoding - The encoding of the object?
123 unsigned long sorted : 1;
124 unsigned long from_array : 1;
125 unsigned long mixed_encoding : 1;
126 unsigned long encoding : 8;
127 unsigned long count : 21;
132 /// fde_end - libgcc defines this field only if some macro is defined. We
133 /// include this field even if it may not there, to make libgcc happy.
136 /// next - At least we know it's a chained list!
137 struct LibgccObject *next;
140 // "kemgr" stuff. Apparently, all frame tables are stored there.
141 extern "C" void _keymgr_set_and_unlock_processwide_ptr(int, void *);
142 extern "C" void *_keymgr_get_and_lock_processwide_ptr(int);
143 #define KEYMGR_GCC3_DW2_OBJ_LIST 302 /* Dwarf2 object list */
145 /// LibgccObjectInfo - libgcc defines this struct as km_object_info. It
146 /// probably contains all dwarf tables that are loaded.
147 struct LibgccObjectInfo {
149 /// seenObjects - LibgccObjects already parsed by the unwinding runtime.
151 struct LibgccObject* seenObjects;
153 /// unseenObjects - LibgccObjects not parsed yet by the unwinding runtime.
155 struct LibgccObject* unseenObjects;
160 /// darwin_register_frame - Since __register_frame does not work with darwin's
161 /// libgcc,we provide our own function, which "tricks" libgcc by modifying the
162 /// "Dwarf2 object list" key.
163 void DarwinRegisterFrame(void* FrameBegin) {
165 LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
166 _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
167 assert(LOI && "This should be preallocated by the runtime");
169 // Allocate a new LibgccObject to represent this frame. Deallocation of this
170 // object may be impossible: since darwin code in libgcc was written after
171 // the ability to dynamically register frames, things may crash if we
173 struct LibgccObject* ob = (struct LibgccObject*)
174 malloc(sizeof(struct LibgccObject));
176 // Do like libgcc for the values of the field.
177 ob->unused1 = (void *)-1;
180 ob->frame = FrameBegin;
182 ob->encoding.b.encoding = llvm::dwarf::DW_EH_PE_omit;
184 // Put the info on both places, as libgcc uses the first or the second
185 // field. Note that we rely on having two pointers here. If fde_end was a
186 // char, things would get complicated.
187 ob->fde_end = (char*)LOI->unseenObjects;
188 ob->next = LOI->unseenObjects;
190 // Update the key's unseenObjects list.
191 LOI->unseenObjects = ob;
193 // Finally update the "key". Apparently, libgcc requires it.
194 _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
201 #endif // HAVE_EHTABLE_SUPPORT
203 /// createJIT - This is the factory method for creating a JIT for the current
204 /// machine, it does not fall back to the interpreter. This takes ownership
206 ExecutionEngine *JIT::createJIT(Module *M,
207 std::string *ErrorStr,
208 JITMemoryManager *JMM,
211 // Try to register the program as a source of symbols to resolve against.
213 // FIXME: Don't do this here.
214 sys::DynamicLibrary::LoadLibraryPermanently(0, NULL);
216 // If the target supports JIT code generation, create the JIT.
217 if (TargetJITInfo *TJ = TM->getJITInfo()) {
218 return new JIT(M, *TM, *TJ, JMM, GVsWithCode);
221 *ErrorStr = "target does not support JIT code generation";
227 /// This class supports the global getPointerToNamedFunction(), which allows
228 /// bugpoint or gdb users to search for a function by name without any context.
230 SmallPtrSet<JIT*, 1> JITs; // Optimize for process containing just 1 JIT.
231 mutable sys::Mutex Lock;
234 MutexGuard guard(Lock);
237 void Remove(JIT *jit) {
238 MutexGuard guard(Lock);
241 void *getPointerToNamedFunction(const char *Name) const {
242 MutexGuard guard(Lock);
243 assert(JITs.size() != 0 && "No Jit registered");
244 //search function in every instance of JIT
245 for (SmallPtrSet<JIT*, 1>::const_iterator Jit = JITs.begin(),
248 if (Function *F = (*Jit)->FindFunctionNamed(Name))
249 return (*Jit)->getPointerToFunction(F);
251 // The function is not available : fallback on the first created (will
252 // search in symbol of the current program/library)
253 return (*JITs.begin())->getPointerToNamedFunction(Name);
256 ManagedStatic<JitPool> AllJits;
259 // getPointerToNamedFunction - This function is used as a global wrapper to
260 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
261 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
262 // need to resolve function(s) that are being mis-codegenerated, so we need to
263 // resolve their addresses at runtime, and this is the way to do it.
264 void *getPointerToNamedFunction(const char *Name) {
265 return AllJits->getPointerToNamedFunction(Name);
269 JIT::JIT(Module *M, TargetMachine &tm, TargetJITInfo &tji,
270 JITMemoryManager *JMM, bool GVsWithCode)
271 : ExecutionEngine(M), TM(tm), TJI(tji), AllocateGVsWithCode(GVsWithCode),
272 isAlreadyCodeGenerating(false) {
273 setTargetData(TM.getTargetData());
275 jitstate = new JITState(M);
278 JCE = createEmitter(*this, JMM, TM);
280 // Register in global list of all JITs.
284 MutexGuard locked(lock);
285 FunctionPassManager &PM = jitstate->getPM(locked);
286 PM.add(new TargetData(*TM.getTargetData()));
288 // Turn the machine code intermediate representation into bytes in memory that
290 if (TM.addPassesToEmitMachineCode(PM, *JCE)) {
291 report_fatal_error("Target does not support machine code emission!");
294 // Register routine for informing unwinding runtime about new EH frames
295 #if HAVE_EHTABLE_SUPPORT
297 struct LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
298 _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
300 // The key is created on demand, and libgcc creates it the first time an
301 // exception occurs. Since we need the key to register frames, we create
304 LOI = (LibgccObjectInfo*)calloc(sizeof(struct LibgccObjectInfo), 1);
305 _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST, LOI);
306 InstallExceptionTableRegister(DarwinRegisterFrame);
307 // Not sure about how to deregister on Darwin.
309 InstallExceptionTableRegister(__register_frame);
310 InstallExceptionTableDeregister(__deregister_frame);
312 #endif // HAVE_EHTABLE_SUPPORT
314 // Initialize passes.
315 PM.doInitialization();
319 // Unregister all exception tables registered by this JIT.
320 DeregisterAllTables();
322 AllJits->Remove(this);
328 /// addModule - Add a new Module to the JIT. If we previously removed the last
329 /// Module, we need re-initialize jitstate with a valid Module.
330 void JIT::addModule(Module *M) {
331 MutexGuard locked(lock);
333 if (Modules.empty()) {
334 assert(!jitstate && "jitstate should be NULL if Modules vector is empty!");
336 jitstate = new JITState(M);
338 FunctionPassManager &PM = jitstate->getPM(locked);
339 PM.add(new TargetData(*TM.getTargetData()));
341 // Turn the machine code intermediate representation into bytes in memory
342 // that may be executed.
343 if (TM.addPassesToEmitMachineCode(PM, *JCE)) {
344 report_fatal_error("Target does not support machine code emission!");
347 // Initialize passes.
348 PM.doInitialization();
351 ExecutionEngine::addModule(M);
354 /// removeModule - If we are removing the last Module, invalidate the jitstate
355 /// since the PassManager it contains references a released Module.
356 bool JIT::removeModule(Module *M) {
357 bool result = ExecutionEngine::removeModule(M);
359 MutexGuard locked(lock);
361 if (jitstate->getModule() == M) {
366 if (!jitstate && !Modules.empty()) {
367 jitstate = new JITState(Modules[0]);
369 FunctionPassManager &PM = jitstate->getPM(locked);
370 PM.add(new TargetData(*TM.getTargetData()));
372 // Turn the machine code intermediate representation into bytes in memory
373 // that may be executed.
374 if (TM.addPassesToEmitMachineCode(PM, *JCE)) {
375 report_fatal_error("Target does not support machine code emission!");
378 // Initialize passes.
379 PM.doInitialization();
384 /// run - Start execution with the specified function and arguments.
386 GenericValue JIT::runFunction(Function *F,
387 const std::vector<GenericValue> &ArgValues) {
388 assert(F && "Function *F was null at entry to run()");
390 void *FPtr = getPointerToFunction(F);
391 assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
392 FunctionType *FTy = F->getFunctionType();
393 Type *RetTy = FTy->getReturnType();
395 assert((FTy->getNumParams() == ArgValues.size() ||
396 (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
397 "Wrong number of arguments passed into function!");
398 assert(FTy->getNumParams() == ArgValues.size() &&
399 "This doesn't support passing arguments through varargs (yet)!");
401 // Handle some common cases first. These cases correspond to common `main'
403 if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
404 switch (ArgValues.size()) {
406 if (FTy->getParamType(0)->isIntegerTy(32) &&
407 FTy->getParamType(1)->isPointerTy() &&
408 FTy->getParamType(2)->isPointerTy()) {
409 int (*PF)(int, char **, const char **) =
410 (int(*)(int, char **, const char **))(intptr_t)FPtr;
412 // Call the function.
414 rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
415 (char **)GVTOP(ArgValues[1]),
416 (const char **)GVTOP(ArgValues[2])));
421 if (FTy->getParamType(0)->isIntegerTy(32) &&
422 FTy->getParamType(1)->isPointerTy()) {
423 int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
425 // Call the function.
427 rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
428 (char **)GVTOP(ArgValues[1])));
433 if (FTy->getNumParams() == 1 &&
434 FTy->getParamType(0)->isIntegerTy(32)) {
436 int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
437 rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
444 // Handle cases where no arguments are passed first.
445 if (ArgValues.empty()) {
447 switch (RetTy->getTypeID()) {
448 default: llvm_unreachable("Unknown return type for function call!");
449 case Type::IntegerTyID: {
450 unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
452 rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
453 else if (BitWidth <= 8)
454 rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
455 else if (BitWidth <= 16)
456 rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
457 else if (BitWidth <= 32)
458 rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
459 else if (BitWidth <= 64)
460 rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
462 llvm_unreachable("Integer types > 64 bits not supported");
466 rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
468 case Type::FloatTyID:
469 rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
471 case Type::DoubleTyID:
472 rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
474 case Type::X86_FP80TyID:
475 case Type::FP128TyID:
476 case Type::PPC_FP128TyID:
477 llvm_unreachable("long double not supported yet");
478 case Type::PointerTyID:
479 return PTOGV(((void*(*)())(intptr_t)FPtr)());
483 // Okay, this is not one of our quick and easy cases. Because we don't have a
484 // full FFI, we have to codegen a nullary stub function that just calls the
485 // function we are interested in, passing in constants for all of the
486 // arguments. Make this function and return.
488 // First, create the function.
489 FunctionType *STy=FunctionType::get(RetTy, false);
490 Function *Stub = Function::Create(STy, Function::InternalLinkage, "",
493 // Insert a basic block.
494 BasicBlock *StubBB = BasicBlock::Create(F->getContext(), "", Stub);
496 // Convert all of the GenericValue arguments over to constants. Note that we
497 // currently don't support varargs.
498 SmallVector<Value*, 8> Args;
499 for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
501 Type *ArgTy = FTy->getParamType(i);
502 const GenericValue &AV = ArgValues[i];
503 switch (ArgTy->getTypeID()) {
504 default: llvm_unreachable("Unknown argument type for function call!");
505 case Type::IntegerTyID:
506 C = ConstantInt::get(F->getContext(), AV.IntVal);
508 case Type::FloatTyID:
509 C = ConstantFP::get(F->getContext(), APFloat(AV.FloatVal));
511 case Type::DoubleTyID:
512 C = ConstantFP::get(F->getContext(), APFloat(AV.DoubleVal));
514 case Type::PPC_FP128TyID:
515 case Type::X86_FP80TyID:
516 case Type::FP128TyID:
517 C = ConstantFP::get(F->getContext(), APFloat(AV.IntVal));
519 case Type::PointerTyID:
520 void *ArgPtr = GVTOP(AV);
521 if (sizeof(void*) == 4)
522 C = ConstantInt::get(Type::getInt32Ty(F->getContext()),
523 (int)(intptr_t)ArgPtr);
525 C = ConstantInt::get(Type::getInt64Ty(F->getContext()),
527 // Cast the integer to pointer
528 C = ConstantExpr::getIntToPtr(C, ArgTy);
534 CallInst *TheCall = CallInst::Create(F, Args, "", StubBB);
535 TheCall->setCallingConv(F->getCallingConv());
536 TheCall->setTailCall();
537 if (!TheCall->getType()->isVoidTy())
538 // Return result of the call.
539 ReturnInst::Create(F->getContext(), TheCall, StubBB);
541 ReturnInst::Create(F->getContext(), StubBB); // Just return void.
543 // Finally, call our nullary stub function.
544 GenericValue Result = runFunction(Stub, std::vector<GenericValue>());
545 // Erase it, since no other function can have a reference to it.
546 Stub->eraseFromParent();
547 // And return the result.
551 void JIT::RegisterJITEventListener(JITEventListener *L) {
554 MutexGuard locked(lock);
555 EventListeners.push_back(L);
557 void JIT::UnregisterJITEventListener(JITEventListener *L) {
560 MutexGuard locked(lock);
561 std::vector<JITEventListener*>::reverse_iterator I=
562 std::find(EventListeners.rbegin(), EventListeners.rend(), L);
563 if (I != EventListeners.rend()) {
564 std::swap(*I, EventListeners.back());
565 EventListeners.pop_back();
568 void JIT::NotifyFunctionEmitted(
570 void *Code, size_t Size,
571 const JITEvent_EmittedFunctionDetails &Details) {
572 MutexGuard locked(lock);
573 for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
574 EventListeners[I]->NotifyFunctionEmitted(F, Code, Size, Details);
578 void JIT::NotifyFreeingMachineCode(void *OldPtr) {
579 MutexGuard locked(lock);
580 for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
581 EventListeners[I]->NotifyFreeingMachineCode(OldPtr);
585 /// runJITOnFunction - Run the FunctionPassManager full of
586 /// just-in-time compilation passes on F, hopefully filling in
587 /// GlobalAddress[F] with the address of F's machine code.
589 void JIT::runJITOnFunction(Function *F, MachineCodeInfo *MCI) {
590 MutexGuard locked(lock);
592 class MCIListener : public JITEventListener {
593 MachineCodeInfo *const MCI;
595 MCIListener(MachineCodeInfo *mci) : MCI(mci) {}
596 virtual void NotifyFunctionEmitted(const Function &,
597 void *Code, size_t Size,
598 const EmittedFunctionDetails &) {
599 MCI->setAddress(Code);
603 MCIListener MCIL(MCI);
605 RegisterJITEventListener(&MCIL);
607 runJITOnFunctionUnlocked(F, locked);
610 UnregisterJITEventListener(&MCIL);
613 void JIT::runJITOnFunctionUnlocked(Function *F, const MutexGuard &locked) {
614 assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
616 jitTheFunction(F, locked);
618 // If the function referred to another function that had not yet been
619 // read from bitcode, and we are jitting non-lazily, emit it now.
620 while (!jitstate->getPendingFunctions(locked).empty()) {
621 Function *PF = jitstate->getPendingFunctions(locked).back();
622 jitstate->getPendingFunctions(locked).pop_back();
624 assert(!PF->hasAvailableExternallyLinkage() &&
625 "Externally-defined function should not be in pending list.");
627 jitTheFunction(PF, locked);
629 // Now that the function has been jitted, ask the JITEmitter to rewrite
630 // the stub with real address of the function.
631 updateFunctionStub(PF);
635 void JIT::jitTheFunction(Function *F, const MutexGuard &locked) {
636 isAlreadyCodeGenerating = true;
637 jitstate->getPM(locked).run(*F);
638 isAlreadyCodeGenerating = false;
640 // clear basic block addresses after this function is done
641 getBasicBlockAddressMap(locked).clear();
644 /// getPointerToFunction - This method is used to get the address of the
645 /// specified function, compiling it if necessary.
647 void *JIT::getPointerToFunction(Function *F) {
649 if (void *Addr = getPointerToGlobalIfAvailable(F))
650 return Addr; // Check if function already code gen'd
652 MutexGuard locked(lock);
654 // Now that this thread owns the lock, make sure we read in the function if it
655 // exists in this Module.
656 std::string ErrorMsg;
657 if (F->Materialize(&ErrorMsg)) {
658 report_fatal_error("Error reading function '" + F->getName()+
659 "' from bitcode file: " + ErrorMsg);
662 // ... and check if another thread has already code gen'd the function.
663 if (void *Addr = getPointerToGlobalIfAvailable(F))
666 if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
667 bool AbortOnFailure = !F->hasExternalWeakLinkage();
668 void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
669 addGlobalMapping(F, Addr);
673 runJITOnFunctionUnlocked(F, locked);
675 void *Addr = getPointerToGlobalIfAvailable(F);
676 assert(Addr && "Code generation didn't add function to GlobalAddress table!");
680 void JIT::addPointerToBasicBlock(const BasicBlock *BB, void *Addr) {
681 MutexGuard locked(lock);
683 BasicBlockAddressMapTy::iterator I =
684 getBasicBlockAddressMap(locked).find(BB);
685 if (I == getBasicBlockAddressMap(locked).end()) {
686 getBasicBlockAddressMap(locked)[BB] = Addr;
688 // ignore repeats: some BBs can be split into few MBBs?
692 void JIT::clearPointerToBasicBlock(const BasicBlock *BB) {
693 MutexGuard locked(lock);
694 getBasicBlockAddressMap(locked).erase(BB);
697 void *JIT::getPointerToBasicBlock(BasicBlock *BB) {
698 // make sure it's function is compiled by JIT
699 (void)getPointerToFunction(BB->getParent());
701 // resolve basic block address
702 MutexGuard locked(lock);
704 BasicBlockAddressMapTy::iterator I =
705 getBasicBlockAddressMap(locked).find(BB);
706 if (I != getBasicBlockAddressMap(locked).end()) {
709 llvm_unreachable("JIT does not have BB address for address-of-label, was"
710 " it eliminated by optimizer?");
714 /// getOrEmitGlobalVariable - Return the address of the specified global
715 /// variable, possibly emitting it to memory if needed. This is used by the
717 void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
718 MutexGuard locked(lock);
720 void *Ptr = getPointerToGlobalIfAvailable(GV);
723 // If the global is external, just remember the address.
724 if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) {
725 #if HAVE___DSO_HANDLE
726 if (GV->getName() == "__dso_handle")
727 return (void*)&__dso_handle;
729 Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName());
731 report_fatal_error("Could not resolve external global address: "
734 addGlobalMapping(GV, Ptr);
736 // If the global hasn't been emitted to memory yet, allocate space and
737 // emit it into memory.
738 Ptr = getMemoryForGV(GV);
739 addGlobalMapping(GV, Ptr);
740 EmitGlobalVariable(GV); // Initialize the variable.
745 /// recompileAndRelinkFunction - This method is used to force a function
746 /// which has already been compiled, to be compiled again, possibly
747 /// after it has been modified. Then the entry to the old copy is overwritten
748 /// with a branch to the new copy. If there was no old copy, this acts
749 /// just like JIT::getPointerToFunction().
751 void *JIT::recompileAndRelinkFunction(Function *F) {
752 void *OldAddr = getPointerToGlobalIfAvailable(F);
754 // If it's not already compiled there is no reason to patch it up.
755 if (OldAddr == 0) { return getPointerToFunction(F); }
757 // Delete the old function mapping.
758 addGlobalMapping(F, 0);
760 // Recodegen the function
763 // Update state, forward the old function to the new function.
764 void *Addr = getPointerToGlobalIfAvailable(F);
765 assert(Addr && "Code generation didn't add function to GlobalAddress table!");
766 TJI.replaceMachineCodeForFunction(OldAddr, Addr);
770 /// getMemoryForGV - This method abstracts memory allocation of global
771 /// variable so that the JIT can allocate thread local variables depending
774 char* JIT::getMemoryForGV(const GlobalVariable* GV) {
777 // GlobalVariable's which are not "constant" will cause trouble in a server
778 // situation. It's returned in the same block of memory as code which may
780 if (isGVCompilationDisabled() && !GV->isConstant()) {
781 report_fatal_error("Compilation of non-internal GlobalValue is disabled!");
784 // Some applications require globals and code to live together, so they may
785 // be allocated into the same buffer, but in general globals are allocated
786 // through the memory manager which puts them near the code but not in the
788 Type *GlobalType = GV->getType()->getElementType();
789 size_t S = getTargetData()->getTypeAllocSize(GlobalType);
790 size_t A = getTargetData()->getPreferredAlignment(GV);
791 if (GV->isThreadLocal()) {
792 MutexGuard locked(lock);
793 Ptr = TJI.allocateThreadLocalMemory(S);
794 } else if (TJI.allocateSeparateGVMemory()) {
796 Ptr = (char*)malloc(S);
798 // Allocate S+A bytes of memory, then use an aligned pointer within that
800 Ptr = (char*)malloc(S+A);
801 unsigned MisAligned = ((intptr_t)Ptr & (A-1));
802 Ptr = Ptr + (MisAligned ? (A-MisAligned) : 0);
804 } else if (AllocateGVsWithCode) {
805 Ptr = (char*)JCE->allocateSpace(S, A);
807 Ptr = (char*)JCE->allocateGlobal(S, A);
812 void JIT::addPendingFunction(Function *F) {
813 MutexGuard locked(lock);
814 jitstate->getPendingFunctions(locked).push_back(F);
818 JITEventListener::~JITEventListener() {}