1//===-- MCJIT.cpp - MC-based Just-in-Time Compiler ------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "MCJIT.h"
11#include "llvm/ADT/STLExtras.h"
12#include "llvm/ExecutionEngine/GenericValue.h"
13#include "llvm/ExecutionEngine/JITEventListener.h"
14#include "llvm/ExecutionEngine/MCJIT.h"
15#include "llvm/ExecutionEngine/SectionMemoryManager.h"
16#include "llvm/IR/DataLayout.h"
17#include "llvm/IR/DerivedTypes.h"
18#include "llvm/IR/Function.h"
19#include "llvm/IR/LegacyPassManager.h"
20#include "llvm/IR/Mangler.h"
21#include "llvm/IR/Module.h"
22#include "llvm/MC/MCAsmInfo.h"
23#include "llvm/Object/Archive.h"
24#include "llvm/Object/ObjectFile.h"
25#include "llvm/Support/DynamicLibrary.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/MemoryBuffer.h"
28#include "llvm/Support/MutexGuard.h"
29
30using namespace llvm;
31
32void ObjectCache::anchor() {}
33
34namespace {
35
36static struct RegisterJIT {
37  RegisterJIT() { MCJIT::Register(); }
38} JITRegistrator;
39
40}
41
42extern "C" void LLVMLinkInMCJIT() {
43}
44
45ExecutionEngine*
46MCJIT::createJIT(std::unique_ptr<Module> M,
47                 std::string *ErrorStr,
48                 std::shared_ptr<MCJITMemoryManager> MemMgr,
49                 std::shared_ptr<RuntimeDyld::SymbolResolver> Resolver,
50                 std::unique_ptr<TargetMachine> TM) {
51  // Try to register the program as a source of symbols to resolve against.
52  //
53  // FIXME: Don't do this here.
54  sys::DynamicLibrary::LoadLibraryPermanently(nullptr, nullptr);
55
56  if (!MemMgr || !Resolver) {
57    auto RTDyldMM = std::make_shared<SectionMemoryManager>();
58    if (!MemMgr)
59      MemMgr = RTDyldMM;
60    if (!Resolver)
61      Resolver = RTDyldMM;
62  }
63
64  return new MCJIT(std::move(M), std::move(TM), std::move(MemMgr),
65                   std::move(Resolver));
66}
67
68MCJIT::MCJIT(std::unique_ptr<Module> M, std::unique_ptr<TargetMachine> TM,
69             std::shared_ptr<MCJITMemoryManager> MemMgr,
70             std::shared_ptr<RuntimeDyld::SymbolResolver> Resolver)
71    : ExecutionEngine(TM->createDataLayout(), std::move(M)), TM(std::move(TM)),
72      Ctx(nullptr), MemMgr(std::move(MemMgr)),
73      Resolver(*this, std::move(Resolver)), Dyld(*this->MemMgr, this->Resolver),
74      ObjCache(nullptr) {
75  // FIXME: We are managing our modules, so we do not want the base class
76  // ExecutionEngine to manage them as well. To avoid double destruction
77  // of the first (and only) module added in ExecutionEngine constructor
78  // we remove it from EE and will destruct it ourselves.
79  //
80  // It may make sense to move our module manager (based on SmallStPtr) back
81  // into EE if the JIT and Interpreter can live with it.
82  // If so, additional functions: addModule, removeModule, FindFunctionNamed,
83  // runStaticConstructorsDestructors could be moved back to EE as well.
84  //
85  std::unique_ptr<Module> First = std::move(Modules[0]);
86  Modules.clear();
87
88  OwnedModules.addModule(std::move(First));
89  RegisterJITEventListener(JITEventListener::createGDBRegistrationListener());
90}
91
92MCJIT::~MCJIT() {
93  MutexGuard locked(lock);
94
95  Dyld.deregisterEHFrames();
96
97  for (auto &Obj : LoadedObjects)
98    if (Obj)
99      NotifyFreeingObject(*Obj);
100
101  Archives.clear();
102}
103
104void MCJIT::addModule(std::unique_ptr<Module> M) {
105  MutexGuard locked(lock);
106  OwnedModules.addModule(std::move(M));
107}
108
109bool MCJIT::removeModule(Module *M) {
110  MutexGuard locked(lock);
111  return OwnedModules.removeModule(M);
112}
113
114void MCJIT::addObjectFile(std::unique_ptr<object::ObjectFile> Obj) {
115  std::unique_ptr<RuntimeDyld::LoadedObjectInfo> L = Dyld.loadObject(*Obj);
116  if (Dyld.hasError())
117    report_fatal_error(Dyld.getErrorString());
118
119  NotifyObjectEmitted(*Obj, *L);
120
121  LoadedObjects.push_back(std::move(Obj));
122}
123
124void MCJIT::addObjectFile(object::OwningBinary<object::ObjectFile> Obj) {
125  std::unique_ptr<object::ObjectFile> ObjFile;
126  std::unique_ptr<MemoryBuffer> MemBuf;
127  std::tie(ObjFile, MemBuf) = Obj.takeBinary();
128  addObjectFile(std::move(ObjFile));
129  Buffers.push_back(std::move(MemBuf));
130}
131
132void MCJIT::addArchive(object::OwningBinary<object::Archive> A) {
133  Archives.push_back(std::move(A));
134}
135
136void MCJIT::setObjectCache(ObjectCache* NewCache) {
137  MutexGuard locked(lock);
138  ObjCache = NewCache;
139}
140
141std::unique_ptr<MemoryBuffer> MCJIT::emitObject(Module *M) {
142  MutexGuard locked(lock);
143
144  // This must be a module which has already been added but not loaded to this
145  // MCJIT instance, since these conditions are tested by our caller,
146  // generateCodeForModule.
147
148  legacy::PassManager PM;
149
150  // The RuntimeDyld will take ownership of this shortly
151  SmallVector<char, 4096> ObjBufferSV;
152  raw_svector_ostream ObjStream(ObjBufferSV);
153
154  // Turn the machine code intermediate representation into bytes in memory
155  // that may be executed.
156  if (TM->addPassesToEmitMC(PM, Ctx, ObjStream, !getVerifyModules()))
157    report_fatal_error("Target does not support MC emission!");
158
159  // Initialize passes.
160  PM.run(*M);
161  // Flush the output buffer to get the generated code into memory
162
163  std::unique_ptr<MemoryBuffer> CompiledObjBuffer(
164                                new ObjectMemoryBuffer(std::move(ObjBufferSV)));
165
166  // If we have an object cache, tell it about the new object.
167  // Note that we're using the compiled image, not the loaded image (as below).
168  if (ObjCache) {
169    // MemoryBuffer is a thin wrapper around the actual memory, so it's OK
170    // to create a temporary object here and delete it after the call.
171    MemoryBufferRef MB = CompiledObjBuffer->getMemBufferRef();
172    ObjCache->notifyObjectCompiled(M, MB);
173  }
174
175  return CompiledObjBuffer;
176}
177
178void MCJIT::generateCodeForModule(Module *M) {
179  // Get a thread lock to make sure we aren't trying to load multiple times
180  MutexGuard locked(lock);
181
182  // This must be a module which has already been added to this MCJIT instance.
183  assert(OwnedModules.ownsModule(M) &&
184         "MCJIT::generateCodeForModule: Unknown module.");
185
186  // Re-compilation is not supported
187  if (OwnedModules.hasModuleBeenLoaded(M))
188    return;
189
190  std::unique_ptr<MemoryBuffer> ObjectToLoad;
191  // Try to load the pre-compiled object from cache if possible
192  if (ObjCache)
193    ObjectToLoad = ObjCache->getObject(M);
194
195  if (M->getDataLayout().isDefault()) {
196    M->setDataLayout(getDataLayout());
197  } else {
198    assert(M->getDataLayout() == getDataLayout() && "DataLayout Mismatch");
199  }
200
201  // If the cache did not contain a suitable object, compile the object
202  if (!ObjectToLoad) {
203    ObjectToLoad = emitObject(M);
204    assert(ObjectToLoad && "Compilation did not produce an object.");
205  }
206
207  // Load the object into the dynamic linker.
208  // MCJIT now owns the ObjectImage pointer (via its LoadedObjects list).
209  ErrorOr<std::unique_ptr<object::ObjectFile>> LoadedObject =
210    object::ObjectFile::createObjectFile(ObjectToLoad->getMemBufferRef());
211  std::unique_ptr<RuntimeDyld::LoadedObjectInfo> L =
212    Dyld.loadObject(*LoadedObject.get());
213
214  if (Dyld.hasError())
215    report_fatal_error(Dyld.getErrorString());
216
217  NotifyObjectEmitted(*LoadedObject.get(), *L);
218
219  Buffers.push_back(std::move(ObjectToLoad));
220  LoadedObjects.push_back(std::move(*LoadedObject));
221
222  OwnedModules.markModuleAsLoaded(M);
223}
224
225void MCJIT::finalizeLoadedModules() {
226  MutexGuard locked(lock);
227
228  // Resolve any outstanding relocations.
229  Dyld.resolveRelocations();
230
231  OwnedModules.markAllLoadedModulesAsFinalized();
232
233  // Register EH frame data for any module we own which has been loaded
234  Dyld.registerEHFrames();
235
236  // Set page permissions.
237  MemMgr->finalizeMemory();
238}
239
240// FIXME: Rename this.
241void MCJIT::finalizeObject() {
242  MutexGuard locked(lock);
243
244  // Generate code for module is going to move objects out of the 'added' list,
245  // so we need to copy that out before using it:
246  SmallVector<Module*, 16> ModsToAdd;
247  for (auto M : OwnedModules.added())
248    ModsToAdd.push_back(M);
249
250  for (auto M : ModsToAdd)
251    generateCodeForModule(M);
252
253  finalizeLoadedModules();
254}
255
256void MCJIT::finalizeModule(Module *M) {
257  MutexGuard locked(lock);
258
259  // This must be a module which has already been added to this MCJIT instance.
260  assert(OwnedModules.ownsModule(M) && "MCJIT::finalizeModule: Unknown module.");
261
262  // If the module hasn't been compiled, just do that.
263  if (!OwnedModules.hasModuleBeenLoaded(M))
264    generateCodeForModule(M);
265
266  finalizeLoadedModules();
267}
268
269RuntimeDyld::SymbolInfo MCJIT::findExistingSymbol(const std::string &Name) {
270  SmallString<128> FullName;
271  Mangler::getNameWithPrefix(FullName, Name, getDataLayout());
272
273  if (void *Addr = getPointerToGlobalIfAvailable(FullName))
274    return RuntimeDyld::SymbolInfo(static_cast<uint64_t>(
275                                     reinterpret_cast<uintptr_t>(Addr)),
276                                   JITSymbolFlags::Exported);
277
278  return Dyld.getSymbol(FullName);
279}
280
281Module *MCJIT::findModuleForSymbol(const std::string &Name,
282                                   bool CheckFunctionsOnly) {
283  MutexGuard locked(lock);
284
285  // If it hasn't already been generated, see if it's in one of our modules.
286  for (ModulePtrSet::iterator I = OwnedModules.begin_added(),
287                              E = OwnedModules.end_added();
288       I != E; ++I) {
289    Module *M = *I;
290    Function *F = M->getFunction(Name);
291    if (F && !F->isDeclaration())
292      return M;
293    if (!CheckFunctionsOnly) {
294      GlobalVariable *G = M->getGlobalVariable(Name);
295      if (G && !G->isDeclaration())
296        return M;
297      // FIXME: Do we need to worry about global aliases?
298    }
299  }
300  // We didn't find the symbol in any of our modules.
301  return nullptr;
302}
303
304uint64_t MCJIT::getSymbolAddress(const std::string &Name,
305                                 bool CheckFunctionsOnly) {
306  return findSymbol(Name, CheckFunctionsOnly).getAddress();
307}
308
309RuntimeDyld::SymbolInfo MCJIT::findSymbol(const std::string &Name,
310                                          bool CheckFunctionsOnly) {
311  MutexGuard locked(lock);
312
313  // First, check to see if we already have this symbol.
314  if (auto Sym = findExistingSymbol(Name))
315    return Sym;
316
317  for (object::OwningBinary<object::Archive> &OB : Archives) {
318    object::Archive *A = OB.getBinary();
319    // Look for our symbols in each Archive
320    object::Archive::child_iterator ChildIt = A->findSym(Name);
321    if (std::error_code EC = ChildIt->getError())
322      report_fatal_error(EC.message());
323    if (ChildIt != A->child_end()) {
324      // FIXME: Support nested archives?
325      ErrorOr<std::unique_ptr<object::Binary>> ChildBinOrErr =
326          (*ChildIt)->getAsBinary();
327      if (ChildBinOrErr.getError())
328        continue;
329      std::unique_ptr<object::Binary> &ChildBin = ChildBinOrErr.get();
330      if (ChildBin->isObject()) {
331        std::unique_ptr<object::ObjectFile> OF(
332            static_cast<object::ObjectFile *>(ChildBin.release()));
333        // This causes the object file to be loaded.
334        addObjectFile(std::move(OF));
335        // The address should be here now.
336        if (auto Sym = findExistingSymbol(Name))
337          return Sym;
338      }
339    }
340  }
341
342  // If it hasn't already been generated, see if it's in one of our modules.
343  Module *M = findModuleForSymbol(Name, CheckFunctionsOnly);
344  if (M) {
345    generateCodeForModule(M);
346
347    // Check the RuntimeDyld table again, it should be there now.
348    return findExistingSymbol(Name);
349  }
350
351  // If a LazyFunctionCreator is installed, use it to get/create the function.
352  // FIXME: Should we instead have a LazySymbolCreator callback?
353  if (LazyFunctionCreator) {
354    auto Addr = static_cast<uint64_t>(
355                  reinterpret_cast<uintptr_t>(LazyFunctionCreator(Name)));
356    return RuntimeDyld::SymbolInfo(Addr, JITSymbolFlags::Exported);
357  }
358
359  return nullptr;
360}
361
362uint64_t MCJIT::getGlobalValueAddress(const std::string &Name) {
363  MutexGuard locked(lock);
364  uint64_t Result = getSymbolAddress(Name, false);
365  if (Result != 0)
366    finalizeLoadedModules();
367  return Result;
368}
369
370uint64_t MCJIT::getFunctionAddress(const std::string &Name) {
371  MutexGuard locked(lock);
372  uint64_t Result = getSymbolAddress(Name, true);
373  if (Result != 0)
374    finalizeLoadedModules();
375  return Result;
376}
377
378// Deprecated.  Use getFunctionAddress instead.
379void *MCJIT::getPointerToFunction(Function *F) {
380  MutexGuard locked(lock);
381
382  Mangler Mang;
383  SmallString<128> Name;
384  TM->getNameWithPrefix(Name, F, Mang);
385
386  if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
387    bool AbortOnFailure = !F->hasExternalWeakLinkage();
388    void *Addr = getPointerToNamedFunction(Name, AbortOnFailure);
389    updateGlobalMapping(F, Addr);
390    return Addr;
391  }
392
393  Module *M = F->getParent();
394  bool HasBeenAddedButNotLoaded = OwnedModules.hasModuleBeenAddedButNotLoaded(M);
395
396  // Make sure the relevant module has been compiled and loaded.
397  if (HasBeenAddedButNotLoaded)
398    generateCodeForModule(M);
399  else if (!OwnedModules.hasModuleBeenLoaded(M)) {
400    // If this function doesn't belong to one of our modules, we're done.
401    // FIXME: Asking for the pointer to a function that hasn't been registered,
402    //        and isn't a declaration (which is handled above) should probably
403    //        be an assertion.
404    return nullptr;
405  }
406
407  // FIXME: Should the Dyld be retaining module information? Probably not.
408  //
409  // This is the accessor for the target address, so make sure to check the
410  // load address of the symbol, not the local address.
411  return (void*)Dyld.getSymbol(Name).getAddress();
412}
413
414void MCJIT::runStaticConstructorsDestructorsInModulePtrSet(
415    bool isDtors, ModulePtrSet::iterator I, ModulePtrSet::iterator E) {
416  for (; I != E; ++I) {
417    ExecutionEngine::runStaticConstructorsDestructors(**I, isDtors);
418  }
419}
420
421void MCJIT::runStaticConstructorsDestructors(bool isDtors) {
422  // Execute global ctors/dtors for each module in the program.
423  runStaticConstructorsDestructorsInModulePtrSet(
424      isDtors, OwnedModules.begin_added(), OwnedModules.end_added());
425  runStaticConstructorsDestructorsInModulePtrSet(
426      isDtors, OwnedModules.begin_loaded(), OwnedModules.end_loaded());
427  runStaticConstructorsDestructorsInModulePtrSet(
428      isDtors, OwnedModules.begin_finalized(), OwnedModules.end_finalized());
429}
430
431Function *MCJIT::FindFunctionNamedInModulePtrSet(const char *FnName,
432                                                 ModulePtrSet::iterator I,
433                                                 ModulePtrSet::iterator E) {
434  for (; I != E; ++I) {
435    Function *F = (*I)->getFunction(FnName);
436    if (F && !F->isDeclaration())
437      return F;
438  }
439  return nullptr;
440}
441
442GlobalVariable *MCJIT::FindGlobalVariableNamedInModulePtrSet(const char *Name,
443                                                             bool AllowInternal,
444                                                             ModulePtrSet::iterator I,
445                                                             ModulePtrSet::iterator E) {
446  for (; I != E; ++I) {
447    GlobalVariable *GV = (*I)->getGlobalVariable(Name, AllowInternal);
448    if (GV && !GV->isDeclaration())
449      return GV;
450  }
451  return nullptr;
452}
453
454
455Function *MCJIT::FindFunctionNamed(const char *FnName) {
456  Function *F = FindFunctionNamedInModulePtrSet(
457      FnName, OwnedModules.begin_added(), OwnedModules.end_added());
458  if (!F)
459    F = FindFunctionNamedInModulePtrSet(FnName, OwnedModules.begin_loaded(),
460                                        OwnedModules.end_loaded());
461  if (!F)
462    F = FindFunctionNamedInModulePtrSet(FnName, OwnedModules.begin_finalized(),
463                                        OwnedModules.end_finalized());
464  return F;
465}
466
467GlobalVariable *MCJIT::FindGlobalVariableNamed(const char *Name, bool AllowInternal) {
468  GlobalVariable *GV = FindGlobalVariableNamedInModulePtrSet(
469      Name, AllowInternal, OwnedModules.begin_added(), OwnedModules.end_added());
470  if (!GV)
471    GV = FindGlobalVariableNamedInModulePtrSet(Name, AllowInternal, OwnedModules.begin_loaded(),
472                                        OwnedModules.end_loaded());
473  if (!GV)
474    GV = FindGlobalVariableNamedInModulePtrSet(Name, AllowInternal, OwnedModules.begin_finalized(),
475                                        OwnedModules.end_finalized());
476  return GV;
477}
478
479GenericValue MCJIT::runFunction(Function *F, ArrayRef<GenericValue> ArgValues) {
480  assert(F && "Function *F was null at entry to run()");
481
482  void *FPtr = getPointerToFunction(F);
483  assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
484  FunctionType *FTy = F->getFunctionType();
485  Type *RetTy = FTy->getReturnType();
486
487  assert((FTy->getNumParams() == ArgValues.size() ||
488          (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
489         "Wrong number of arguments passed into function!");
490  assert(FTy->getNumParams() == ArgValues.size() &&
491         "This doesn't support passing arguments through varargs (yet)!");
492
493  // Handle some common cases first.  These cases correspond to common `main'
494  // prototypes.
495  if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
496    switch (ArgValues.size()) {
497    case 3:
498      if (FTy->getParamType(0)->isIntegerTy(32) &&
499          FTy->getParamType(1)->isPointerTy() &&
500          FTy->getParamType(2)->isPointerTy()) {
501        int (*PF)(int, char **, const char **) =
502          (int(*)(int, char **, const char **))(intptr_t)FPtr;
503
504        // Call the function.
505        GenericValue rv;
506        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
507                                 (char **)GVTOP(ArgValues[1]),
508                                 (const char **)GVTOP(ArgValues[2])));
509        return rv;
510      }
511      break;
512    case 2:
513      if (FTy->getParamType(0)->isIntegerTy(32) &&
514          FTy->getParamType(1)->isPointerTy()) {
515        int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
516
517        // Call the function.
518        GenericValue rv;
519        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
520                                 (char **)GVTOP(ArgValues[1])));
521        return rv;
522      }
523      break;
524    case 1:
525      if (FTy->getNumParams() == 1 &&
526          FTy->getParamType(0)->isIntegerTy(32)) {
527        GenericValue rv;
528        int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
529        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
530        return rv;
531      }
532      break;
533    }
534  }
535
536  // Handle cases where no arguments are passed first.
537  if (ArgValues.empty()) {
538    GenericValue rv;
539    switch (RetTy->getTypeID()) {
540    default: llvm_unreachable("Unknown return type for function call!");
541    case Type::IntegerTyID: {
542      unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
543      if (BitWidth == 1)
544        rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
545      else if (BitWidth <= 8)
546        rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
547      else if (BitWidth <= 16)
548        rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
549      else if (BitWidth <= 32)
550        rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
551      else if (BitWidth <= 64)
552        rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
553      else
554        llvm_unreachable("Integer types > 64 bits not supported");
555      return rv;
556    }
557    case Type::VoidTyID:
558      rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
559      return rv;
560    case Type::FloatTyID:
561      rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
562      return rv;
563    case Type::DoubleTyID:
564      rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
565      return rv;
566    case Type::X86_FP80TyID:
567    case Type::FP128TyID:
568    case Type::PPC_FP128TyID:
569      llvm_unreachable("long double not supported yet");
570    case Type::PointerTyID:
571      return PTOGV(((void*(*)())(intptr_t)FPtr)());
572    }
573  }
574
575  llvm_unreachable("Full-featured argument passing not supported yet!");
576}
577
578void *MCJIT::getPointerToNamedFunction(StringRef Name, bool AbortOnFailure) {
579  if (!isSymbolSearchingDisabled()) {
580    void *ptr =
581      reinterpret_cast<void*>(
582        static_cast<uintptr_t>(Resolver.findSymbol(Name).getAddress()));
583    if (ptr)
584      return ptr;
585  }
586
587  /// If a LazyFunctionCreator is installed, use it to get/create the function.
588  if (LazyFunctionCreator)
589    if (void *RP = LazyFunctionCreator(Name))
590      return RP;
591
592  if (AbortOnFailure) {
593    report_fatal_error("Program used external function '"+Name+
594                       "' which could not be resolved!");
595  }
596  return nullptr;
597}
598
599void MCJIT::RegisterJITEventListener(JITEventListener *L) {
600  if (!L)
601    return;
602  MutexGuard locked(lock);
603  EventListeners.push_back(L);
604}
605
606void MCJIT::UnregisterJITEventListener(JITEventListener *L) {
607  if (!L)
608    return;
609  MutexGuard locked(lock);
610  auto I = std::find(EventListeners.rbegin(), EventListeners.rend(), L);
611  if (I != EventListeners.rend()) {
612    std::swap(*I, EventListeners.back());
613    EventListeners.pop_back();
614  }
615}
616
617void MCJIT::NotifyObjectEmitted(const object::ObjectFile& Obj,
618                                const RuntimeDyld::LoadedObjectInfo &L) {
619  MutexGuard locked(lock);
620  MemMgr->notifyObjectLoaded(this, Obj);
621  for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
622    EventListeners[I]->NotifyObjectEmitted(Obj, L);
623  }
624}
625
626void MCJIT::NotifyFreeingObject(const object::ObjectFile& Obj) {
627  MutexGuard locked(lock);
628  for (JITEventListener *L : EventListeners)
629    L->NotifyFreeingObject(Obj);
630}
631
632RuntimeDyld::SymbolInfo
633LinkingSymbolResolver::findSymbol(const std::string &Name) {
634  auto Result = ParentEngine.findSymbol(Name, false);
635  // If the symbols wasn't found and it begins with an underscore, try again
636  // without the underscore.
637  if (!Result && Name[0] == '_')
638    Result = ParentEngine.findSymbol(Name.substr(1), false);
639  if (Result)
640    return Result;
641  if (ParentEngine.isSymbolSearchingDisabled())
642    return nullptr;
643  return ClientResolver->findSymbol(Name);
644}
645