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/ModuleProvider.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/MutexGuard.h"
32 #include "llvm/System/DynamicLibrary.h"
33 #include "llvm/Config/config.h"
38 // Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
39 // of atexit). It passes the address of linker generated symbol __dso_handle
41 // This configuration change happened at version 5330.
42 # include <AvailabilityMacros.h>
43 # if defined(MAC_OS_X_VERSION_10_4) && \
44 ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
45 (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
46 __APPLE_CC__ >= 5330))
47 # ifndef HAVE___DSO_HANDLE
48 # define HAVE___DSO_HANDLE 1
54 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
59 static struct RegisterJIT {
60 RegisterJIT() { JIT::Register(); }
65 extern "C" void LLVMLinkInJIT() {
69 #if defined(__GNUC__) && !defined(__ARM__EABI__)
71 // libgcc defines the __register_frame function to dynamically register new
72 // dwarf frames for exception handling. This functionality is not portable
73 // across compilers and is only provided by GCC. We use the __register_frame
74 // function here so that code generated by the JIT cooperates with the unwinding
75 // runtime of libgcc. When JITting with exception handling enable, LLVM
76 // generates dwarf frames and registers it to libgcc with __register_frame.
78 // The __register_frame function works with Linux.
80 // Unfortunately, this functionality seems to be in libgcc after the unwinding
81 // library of libgcc for darwin was written. The code for darwin overwrites the
82 // value updated by __register_frame with a value fetched with "keymgr".
83 // "keymgr" is an obsolete functionality, which should be rewritten some day.
84 // In the meantime, since "keymgr" is on all libgccs shipped with apple-gcc, we
85 // need a workaround in LLVM which uses the "keymgr" to dynamically modify the
86 // values of an opaque key, used by libgcc to find dwarf tables.
88 extern "C" void __register_frame(void*);
90 #if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED <= 1050
100 // LibgccObject - This is the structure defined in libgcc. There is no #include
101 // provided for this structure, so we also define it here. libgcc calls it
102 // "struct object". The structure is undocumented in libgcc.
103 struct LibgccObject {
108 /// frame - Pointer to the exception table.
111 /// encoding - The encoding of the object?
114 unsigned long sorted : 1;
115 unsigned long from_array : 1;
116 unsigned long mixed_encoding : 1;
117 unsigned long encoding : 8;
118 unsigned long count : 21;
123 /// fde_end - libgcc defines this field only if some macro is defined. We
124 /// include this field even if it may not there, to make libgcc happy.
127 /// next - At least we know it's a chained list!
128 struct LibgccObject *next;
131 // "kemgr" stuff. Apparently, all frame tables are stored there.
132 extern "C" void _keymgr_set_and_unlock_processwide_ptr(int, void *);
133 extern "C" void *_keymgr_get_and_lock_processwide_ptr(int);
134 #define KEYMGR_GCC3_DW2_OBJ_LIST 302 /* Dwarf2 object list */
136 /// LibgccObjectInfo - libgcc defines this struct as km_object_info. It
137 /// probably contains all dwarf tables that are loaded.
138 struct LibgccObjectInfo {
140 /// seenObjects - LibgccObjects already parsed by the unwinding runtime.
142 struct LibgccObject* seenObjects;
144 /// unseenObjects - LibgccObjects not parsed yet by the unwinding runtime.
146 struct LibgccObject* unseenObjects;
151 /// darwin_register_frame - Since __register_frame does not work with darwin's
152 /// libgcc,we provide our own function, which "tricks" libgcc by modifying the
153 /// "Dwarf2 object list" key.
154 void DarwinRegisterFrame(void* FrameBegin) {
156 LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
157 _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
158 assert(LOI && "This should be preallocated by the runtime");
160 // Allocate a new LibgccObject to represent this frame. Deallocation of this
161 // object may be impossible: since darwin code in libgcc was written after
162 // the ability to dynamically register frames, things may crash if we
164 struct LibgccObject* ob = (struct LibgccObject*)
165 malloc(sizeof(struct LibgccObject));
167 // Do like libgcc for the values of the field.
168 ob->unused1 = (void *)-1;
171 ob->frame = FrameBegin;
173 ob->encoding.b.encoding = llvm::dwarf::DW_EH_PE_omit;
175 // Put the info on both places, as libgcc uses the first or the the second
176 // field. Note that we rely on having two pointers here. If fde_end was a
177 // char, things would get complicated.
178 ob->fde_end = (char*)LOI->unseenObjects;
179 ob->next = LOI->unseenObjects;
181 // Update the key's unseenObjects list.
182 LOI->unseenObjects = ob;
184 // Finally update the "key". Apparently, libgcc requires it.
185 _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
194 /// createJIT - This is the factory method for creating a JIT for the current
195 /// machine, it does not fall back to the interpreter. This takes ownership
196 /// of the module provider.
197 ExecutionEngine *ExecutionEngine::createJIT(ModuleProvider *MP,
198 std::string *ErrorStr,
199 JITMemoryManager *JMM,
200 CodeGenOpt::Level OptLevel,
202 CodeModel::Model CMM) {
203 return JIT::createJIT(MP, ErrorStr, JMM, OptLevel, GVsWithCode, CMM);
206 ExecutionEngine *JIT::createJIT(ModuleProvider *MP,
207 std::string *ErrorStr,
208 JITMemoryManager *JMM,
209 CodeGenOpt::Level OptLevel,
211 CodeModel::Model CMM) {
212 // Make sure we can resolve symbols in the program as well. The zero arg
213 // to the function tells DynamicLibrary to load the program, not a library.
214 if (sys::DynamicLibrary::LoadLibraryPermanently(0, ErrorStr))
217 // Pick a target either via -march or by guessing the native arch.
218 TargetMachine *TM = JIT::selectTarget(MP, ErrorStr);
219 if (!TM || (ErrorStr && ErrorStr->length() > 0)) return 0;
220 TM->setCodeModel(CMM);
222 // If the target supports JIT code generation, create a the JIT.
223 if (TargetJITInfo *TJ = TM->getJITInfo()) {
224 return new JIT(MP, *TM, *TJ, JMM, OptLevel, GVsWithCode);
227 *ErrorStr = "target does not support JIT code generation";
232 JIT::JIT(ModuleProvider *MP, TargetMachine &tm, TargetJITInfo &tji,
233 JITMemoryManager *JMM, CodeGenOpt::Level OptLevel, bool GVsWithCode)
234 : ExecutionEngine(MP), TM(tm), TJI(tji), AllocateGVsWithCode(GVsWithCode) {
235 setTargetData(TM.getTargetData());
237 jitstate = new JITState(MP);
240 JCE = createEmitter(*this, JMM, TM);
243 MutexGuard locked(lock);
244 FunctionPassManager &PM = jitstate->getPM(locked);
245 PM.add(new TargetData(*TM.getTargetData()));
247 // Turn the machine code intermediate representation into bytes in memory that
249 if (TM.addPassesToEmitMachineCode(PM, *JCE, OptLevel)) {
250 llvm_report_error("Target does not support machine code emission!");
253 // Register routine for informing unwinding runtime about new EH frames
254 #if defined(__GNUC__) && !defined(__ARM_EABI__)
256 struct LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
257 _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
259 // The key is created on demand, and libgcc creates it the first time an
260 // exception occurs. Since we need the key to register frames, we create
263 LOI = (LibgccObjectInfo*)calloc(sizeof(struct LibgccObjectInfo), 1);
264 _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST, LOI);
265 InstallExceptionTableRegister(DarwinRegisterFrame);
267 InstallExceptionTableRegister(__register_frame);
271 // Initialize passes.
272 PM.doInitialization();
281 /// addModuleProvider - Add a new ModuleProvider to the JIT. If we previously
282 /// removed the last ModuleProvider, we need re-initialize jitstate with a valid
284 void JIT::addModuleProvider(ModuleProvider *MP) {
285 MutexGuard locked(lock);
287 if (Modules.empty()) {
288 assert(!jitstate && "jitstate should be NULL if Modules vector is empty!");
290 jitstate = new JITState(MP);
292 FunctionPassManager &PM = jitstate->getPM(locked);
293 PM.add(new TargetData(*TM.getTargetData()));
295 // Turn the machine code intermediate representation into bytes in memory
296 // that may be executed.
297 if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
298 llvm_report_error("Target does not support machine code emission!");
301 // Initialize passes.
302 PM.doInitialization();
305 ExecutionEngine::addModuleProvider(MP);
308 /// removeModuleProvider - If we are removing the last ModuleProvider,
309 /// invalidate the jitstate since the PassManager it contains references a
310 /// released ModuleProvider.
311 Module *JIT::removeModuleProvider(ModuleProvider *MP, std::string *E) {
312 Module *result = ExecutionEngine::removeModuleProvider(MP, E);
314 MutexGuard locked(lock);
316 if (jitstate->getMP() == MP) {
321 if (!jitstate && !Modules.empty()) {
322 jitstate = new JITState(Modules[0]);
324 FunctionPassManager &PM = jitstate->getPM(locked);
325 PM.add(new TargetData(*TM.getTargetData()));
327 // Turn the machine code intermediate representation into bytes in memory
328 // that may be executed.
329 if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
330 llvm_report_error("Target does not support machine code emission!");
333 // Initialize passes.
334 PM.doInitialization();
339 /// deleteModuleProvider - Remove a ModuleProvider from the list of modules,
340 /// and deletes the ModuleProvider and owned Module. Avoids materializing
341 /// the underlying module.
342 void JIT::deleteModuleProvider(ModuleProvider *MP, std::string *E) {
343 ExecutionEngine::deleteModuleProvider(MP, E);
345 MutexGuard locked(lock);
347 if (jitstate->getMP() == MP) {
352 if (!jitstate && !Modules.empty()) {
353 jitstate = new JITState(Modules[0]);
355 FunctionPassManager &PM = jitstate->getPM(locked);
356 PM.add(new TargetData(*TM.getTargetData()));
358 // Turn the machine code intermediate representation into bytes in memory
359 // that may be executed.
360 if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
361 llvm_report_error("Target does not support machine code emission!");
364 // Initialize passes.
365 PM.doInitialization();
369 /// materializeFunction - make sure the given function is fully read. If the
370 /// module is corrupt, this returns true and fills in the optional string with
371 /// information about the problem. If successful, this returns false.
372 bool JIT::materializeFunction(Function *F, std::string *ErrInfo) {
373 // Read in the function if it exists in this Module.
374 if (F->hasNotBeenReadFromBitcode()) {
375 // Determine the module provider this function is provided by.
376 Module *M = F->getParent();
377 ModuleProvider *MP = 0;
378 for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
379 if (Modules[i]->getModule() == M) {
385 return MP->materializeFunction(F, ErrInfo);
388 *ErrInfo = "Function isn't in a module we know about!";
391 // Succeed if the function is already read.
395 /// run - Start execution with the specified function and arguments.
397 GenericValue JIT::runFunction(Function *F,
398 const std::vector<GenericValue> &ArgValues) {
399 assert(F && "Function *F was null at entry to run()");
401 void *FPtr = getPointerToFunction(F);
402 assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
403 const FunctionType *FTy = F->getFunctionType();
404 const Type *RetTy = FTy->getReturnType();
406 assert((FTy->getNumParams() == ArgValues.size() ||
407 (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
408 "Wrong number of arguments passed into function!");
409 assert(FTy->getNumParams() == ArgValues.size() &&
410 "This doesn't support passing arguments through varargs (yet)!");
412 // Handle some common cases first. These cases correspond to common `main'
414 if (RetTy == Type::getInt32Ty(F->getContext()) || RetTy->isVoidTy()) {
415 switch (ArgValues.size()) {
417 if (FTy->getParamType(0)->isInteger(32) &&
418 isa<PointerType>(FTy->getParamType(1)) &&
419 isa<PointerType>(FTy->getParamType(2))) {
420 int (*PF)(int, char **, const char **) =
421 (int(*)(int, char **, const char **))(intptr_t)FPtr;
423 // Call the function.
425 rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
426 (char **)GVTOP(ArgValues[1]),
427 (const char **)GVTOP(ArgValues[2])));
432 if (FTy->getParamType(0)->isInteger(32) &&
433 isa<PointerType>(FTy->getParamType(1))) {
434 int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
436 // Call the function.
438 rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
439 (char **)GVTOP(ArgValues[1])));
444 if (FTy->getNumParams() == 1 &&
445 FTy->getParamType(0)->isInteger(32)) {
447 int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
448 rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
455 // Handle cases where no arguments are passed first.
456 if (ArgValues.empty()) {
458 switch (RetTy->getTypeID()) {
459 default: llvm_unreachable("Unknown return type for function call!");
460 case Type::IntegerTyID: {
461 unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
463 rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
464 else if (BitWidth <= 8)
465 rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
466 else if (BitWidth <= 16)
467 rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
468 else if (BitWidth <= 32)
469 rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
470 else if (BitWidth <= 64)
471 rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
473 llvm_unreachable("Integer types > 64 bits not supported");
477 rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
479 case Type::FloatTyID:
480 rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
482 case Type::DoubleTyID:
483 rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
485 case Type::X86_FP80TyID:
486 case Type::FP128TyID:
487 case Type::PPC_FP128TyID:
488 llvm_unreachable("long double not supported yet");
490 case Type::PointerTyID:
491 return PTOGV(((void*(*)())(intptr_t)FPtr)());
495 // Okay, this is not one of our quick and easy cases. Because we don't have a
496 // full FFI, we have to codegen a nullary stub function that just calls the
497 // function we are interested in, passing in constants for all of the
498 // arguments. Make this function and return.
500 // First, create the function.
501 FunctionType *STy=FunctionType::get(RetTy, false);
502 Function *Stub = Function::Create(STy, Function::InternalLinkage, "",
505 // Insert a basic block.
506 BasicBlock *StubBB = BasicBlock::Create(F->getContext(), "", Stub);
508 // Convert all of the GenericValue arguments over to constants. Note that we
509 // currently don't support varargs.
510 SmallVector<Value*, 8> Args;
511 for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
513 const Type *ArgTy = FTy->getParamType(i);
514 const GenericValue &AV = ArgValues[i];
515 switch (ArgTy->getTypeID()) {
516 default: llvm_unreachable("Unknown argument type for function call!");
517 case Type::IntegerTyID:
518 C = ConstantInt::get(F->getContext(), AV.IntVal);
520 case Type::FloatTyID:
521 C = ConstantFP::get(F->getContext(), APFloat(AV.FloatVal));
523 case Type::DoubleTyID:
524 C = ConstantFP::get(F->getContext(), APFloat(AV.DoubleVal));
526 case Type::PPC_FP128TyID:
527 case Type::X86_FP80TyID:
528 case Type::FP128TyID:
529 C = ConstantFP::get(F->getContext(), APFloat(AV.IntVal));
531 case Type::PointerTyID:
532 void *ArgPtr = GVTOP(AV);
533 if (sizeof(void*) == 4)
534 C = ConstantInt::get(Type::getInt32Ty(F->getContext()),
535 (int)(intptr_t)ArgPtr);
537 C = ConstantInt::get(Type::getInt64Ty(F->getContext()),
539 // Cast the integer to pointer
540 C = ConstantExpr::getIntToPtr(C, ArgTy);
546 CallInst *TheCall = CallInst::Create(F, Args.begin(), Args.end(),
548 TheCall->setCallingConv(F->getCallingConv());
549 TheCall->setTailCall();
550 if (!TheCall->getType()->isVoidTy())
551 // Return result of the call.
552 ReturnInst::Create(F->getContext(), TheCall, StubBB);
554 ReturnInst::Create(F->getContext(), StubBB); // Just return void.
556 // Finally, return the value returned by our nullary stub function.
557 return runFunction(Stub, std::vector<GenericValue>());
560 void JIT::RegisterJITEventListener(JITEventListener *L) {
563 MutexGuard locked(lock);
564 EventListeners.push_back(L);
566 void JIT::UnregisterJITEventListener(JITEventListener *L) {
569 MutexGuard locked(lock);
570 std::vector<JITEventListener*>::reverse_iterator I=
571 std::find(EventListeners.rbegin(), EventListeners.rend(), L);
572 if (I != EventListeners.rend()) {
573 std::swap(*I, EventListeners.back());
574 EventListeners.pop_back();
577 void JIT::NotifyFunctionEmitted(
579 void *Code, size_t Size,
580 const JITEvent_EmittedFunctionDetails &Details) {
581 MutexGuard locked(lock);
582 for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
583 EventListeners[I]->NotifyFunctionEmitted(F, Code, Size, Details);
587 void JIT::NotifyFreeingMachineCode(void *OldPtr) {
588 MutexGuard locked(lock);
589 for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
590 EventListeners[I]->NotifyFreeingMachineCode(OldPtr);
594 /// runJITOnFunction - Run the FunctionPassManager full of
595 /// just-in-time compilation passes on F, hopefully filling in
596 /// GlobalAddress[F] with the address of F's machine code.
598 void JIT::runJITOnFunction(Function *F, MachineCodeInfo *MCI) {
599 MutexGuard locked(lock);
601 class MCIListener : public JITEventListener {
602 MachineCodeInfo *const MCI;
604 MCIListener(MachineCodeInfo *mci) : MCI(mci) {}
605 virtual void NotifyFunctionEmitted(const Function &,
606 void *Code, size_t Size,
607 const EmittedFunctionDetails &) {
608 MCI->setAddress(Code);
612 MCIListener MCIL(MCI);
614 RegisterJITEventListener(&MCIL);
616 runJITOnFunctionUnlocked(F, locked);
619 UnregisterJITEventListener(&MCIL);
622 void JIT::runJITOnFunctionUnlocked(Function *F, const MutexGuard &locked) {
623 static bool isAlreadyCodeGenerating = false;
624 assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
627 isAlreadyCodeGenerating = true;
628 jitstate->getPM(locked).run(*F);
629 isAlreadyCodeGenerating = false;
631 // If the function referred to another function that had not yet been
632 // read from bitcode, and we are jitting non-lazily, emit it now.
633 while (!jitstate->getPendingFunctions(locked).empty()) {
634 Function *PF = jitstate->getPendingFunctions(locked).back();
635 jitstate->getPendingFunctions(locked).pop_back();
637 assert(!PF->hasAvailableExternallyLinkage() &&
638 "Externally-defined function should not be in pending list.");
641 isAlreadyCodeGenerating = true;
642 jitstate->getPM(locked).run(*PF);
643 isAlreadyCodeGenerating = false;
645 // Now that the function has been jitted, ask the JITEmitter to rewrite
646 // the stub with real address of the function.
647 updateFunctionStub(PF);
651 /// getPointerToFunction - This method is used to get the address of the
652 /// specified function, compiling it if neccesary.
654 void *JIT::getPointerToFunction(Function *F) {
656 if (void *Addr = getPointerToGlobalIfAvailable(F))
657 return Addr; // Check if function already code gen'd
659 MutexGuard locked(lock);
661 // Now that this thread owns the lock, make sure we read in the function if it
662 // exists in this Module.
663 std::string ErrorMsg;
664 if (materializeFunction(F, &ErrorMsg)) {
665 llvm_report_error("Error reading function '" + F->getName()+
666 "' from bitcode file: " + ErrorMsg);
669 // ... and check if another thread has already code gen'd the function.
670 if (void *Addr = getPointerToGlobalIfAvailable(F))
673 if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
674 bool AbortOnFailure = !F->hasExternalWeakLinkage();
675 void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
676 addGlobalMapping(F, Addr);
680 runJITOnFunctionUnlocked(F, locked);
682 void *Addr = getPointerToGlobalIfAvailable(F);
683 assert(Addr && "Code generation didn't add function to GlobalAddress table!");
687 /// getOrEmitGlobalVariable - Return the address of the specified global
688 /// variable, possibly emitting it to memory if needed. This is used by the
690 void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
691 MutexGuard locked(lock);
693 void *Ptr = getPointerToGlobalIfAvailable(GV);
696 // If the global is external, just remember the address.
697 if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) {
698 #if HAVE___DSO_HANDLE
699 if (GV->getName() == "__dso_handle")
700 return (void*)&__dso_handle;
702 Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName());
704 llvm_report_error("Could not resolve external global address: "
707 addGlobalMapping(GV, Ptr);
709 // If the global hasn't been emitted to memory yet, allocate space and
710 // emit it into memory.
711 Ptr = getMemoryForGV(GV);
712 addGlobalMapping(GV, Ptr);
713 EmitGlobalVariable(GV); // Initialize the variable.
718 /// recompileAndRelinkFunction - This method is used to force a function
719 /// which has already been compiled, to be compiled again, possibly
720 /// after it has been modified. Then the entry to the old copy is overwritten
721 /// with a branch to the new copy. If there was no old copy, this acts
722 /// just like JIT::getPointerToFunction().
724 void *JIT::recompileAndRelinkFunction(Function *F) {
725 void *OldAddr = getPointerToGlobalIfAvailable(F);
727 // If it's not already compiled there is no reason to patch it up.
728 if (OldAddr == 0) { return getPointerToFunction(F); }
730 // Delete the old function mapping.
731 addGlobalMapping(F, 0);
733 // Recodegen the function
736 // Update state, forward the old function to the new function.
737 void *Addr = getPointerToGlobalIfAvailable(F);
738 assert(Addr && "Code generation didn't add function to GlobalAddress table!");
739 TJI.replaceMachineCodeForFunction(OldAddr, Addr);
743 /// getMemoryForGV - This method abstracts memory allocation of global
744 /// variable so that the JIT can allocate thread local variables depending
747 char* JIT::getMemoryForGV(const GlobalVariable* GV) {
750 // GlobalVariable's which are not "constant" will cause trouble in a server
751 // situation. It's returned in the same block of memory as code which may
753 if (isGVCompilationDisabled() && !GV->isConstant()) {
754 llvm_report_error("Compilation of non-internal GlobalValue is disabled!");
757 // Some applications require globals and code to live together, so they may
758 // be allocated into the same buffer, but in general globals are allocated
759 // through the memory manager which puts them near the code but not in the
761 const Type *GlobalType = GV->getType()->getElementType();
762 size_t S = getTargetData()->getTypeAllocSize(GlobalType);
763 size_t A = getTargetData()->getPreferredAlignment(GV);
764 if (GV->isThreadLocal()) {
765 MutexGuard locked(lock);
766 Ptr = TJI.allocateThreadLocalMemory(S);
767 } else if (TJI.allocateSeparateGVMemory()) {
769 Ptr = (char*)malloc(S);
771 // Allocate S+A bytes of memory, then use an aligned pointer within that
773 Ptr = (char*)malloc(S+A);
774 unsigned MisAligned = ((intptr_t)Ptr & (A-1));
775 Ptr = Ptr + (MisAligned ? (A-MisAligned) : 0);
777 } else if (AllocateGVsWithCode) {
778 Ptr = (char*)JCE->allocateSpace(S, A);
780 Ptr = (char*)JCE->allocateGlobal(S, A);
785 void JIT::addPendingFunction(Function *F) {
786 MutexGuard locked(lock);
787 jitstate->getPendingFunctions(locked).push_back(F);
791 JITEventListener::~JITEventListener() {}