xref: /freebsd/contrib/llvm-project/llvm/lib/ExecutionEngine/MCJIT/MCJIT.cpp (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 //===-- MCJIT.cpp - MC-based Just-in-Time Compiler ------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "MCJIT.h"
10 #include "llvm/ADT/STLExtras.h"
11 #include "llvm/ExecutionEngine/GenericValue.h"
12 #include "llvm/ExecutionEngine/JITEventListener.h"
13 #include "llvm/ExecutionEngine/MCJIT.h"
14 #include "llvm/ExecutionEngine/ObjectCache.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/Object/Archive.h"
23 #include "llvm/Object/ObjectFile.h"
24 #include "llvm/Support/DynamicLibrary.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/SmallVectorMemoryBuffer.h"
28 #include <mutex>
29 
30 using namespace llvm;
31 
32 namespace {
33 
34 static struct RegisterJIT {
35   RegisterJIT() { MCJIT::Register(); }
36 } JITRegistrator;
37 
38 }
39 
40 extern "C" void LLVMLinkInMCJIT() {
41 }
42 
43 ExecutionEngine *
44 MCJIT::createJIT(std::unique_ptr<Module> M, std::string *ErrorStr,
45                  std::shared_ptr<MCJITMemoryManager> MemMgr,
46                  std::shared_ptr<LegacyJITSymbolResolver> Resolver,
47                  std::unique_ptr<TargetMachine> TM) {
48   // Try to register the program as a source of symbols to resolve against.
49   //
50   // FIXME: Don't do this here.
51   sys::DynamicLibrary::LoadLibraryPermanently(nullptr, nullptr);
52 
53   if (!MemMgr || !Resolver) {
54     auto RTDyldMM = std::make_shared<SectionMemoryManager>();
55     if (!MemMgr)
56       MemMgr = RTDyldMM;
57     if (!Resolver)
58       Resolver = RTDyldMM;
59   }
60 
61   return new MCJIT(std::move(M), std::move(TM), std::move(MemMgr),
62                    std::move(Resolver));
63 }
64 
65 MCJIT::MCJIT(std::unique_ptr<Module> M, std::unique_ptr<TargetMachine> TM,
66              std::shared_ptr<MCJITMemoryManager> MemMgr,
67              std::shared_ptr<LegacyJITSymbolResolver> Resolver)
68     : ExecutionEngine(TM->createDataLayout(), std::move(M)), TM(std::move(TM)),
69       Ctx(nullptr), MemMgr(std::move(MemMgr)),
70       Resolver(*this, std::move(Resolver)), Dyld(*this->MemMgr, this->Resolver),
71       ObjCache(nullptr) {
72   // FIXME: We are managing our modules, so we do not want the base class
73   // ExecutionEngine to manage them as well. To avoid double destruction
74   // of the first (and only) module added in ExecutionEngine constructor
75   // we remove it from EE and will destruct it ourselves.
76   //
77   // It may make sense to move our module manager (based on SmallStPtr) back
78   // into EE if the JIT and Interpreter can live with it.
79   // If so, additional functions: addModule, removeModule, FindFunctionNamed,
80   // runStaticConstructorsDestructors could be moved back to EE as well.
81   //
82   std::unique_ptr<Module> First = std::move(Modules[0]);
83   Modules.clear();
84 
85   if (First->getDataLayout().isDefault())
86     First->setDataLayout(getDataLayout());
87 
88   OwnedModules.addModule(std::move(First));
89   RegisterJITEventListener(JITEventListener::createGDBRegistrationListener());
90 }
91 
92 MCJIT::~MCJIT() {
93   std::lock_guard<sys::Mutex> locked(lock);
94 
95   Dyld.deregisterEHFrames();
96 
97   for (auto &Obj : LoadedObjects)
98     if (Obj)
99       notifyFreeingObject(*Obj);
100 
101   Archives.clear();
102 }
103 
104 void MCJIT::addModule(std::unique_ptr<Module> M) {
105   std::lock_guard<sys::Mutex> locked(lock);
106 
107   if (M->getDataLayout().isDefault())
108     M->setDataLayout(getDataLayout());
109 
110   OwnedModules.addModule(std::move(M));
111 }
112 
113 bool MCJIT::removeModule(Module *M) {
114   std::lock_guard<sys::Mutex> locked(lock);
115   return OwnedModules.removeModule(M);
116 }
117 
118 void MCJIT::addObjectFile(std::unique_ptr<object::ObjectFile> Obj) {
119   std::unique_ptr<RuntimeDyld::LoadedObjectInfo> L = Dyld.loadObject(*Obj);
120   if (Dyld.hasError())
121     report_fatal_error(Dyld.getErrorString());
122 
123   notifyObjectLoaded(*Obj, *L);
124 
125   LoadedObjects.push_back(std::move(Obj));
126 }
127 
128 void MCJIT::addObjectFile(object::OwningBinary<object::ObjectFile> Obj) {
129   std::unique_ptr<object::ObjectFile> ObjFile;
130   std::unique_ptr<MemoryBuffer> MemBuf;
131   std::tie(ObjFile, MemBuf) = Obj.takeBinary();
132   addObjectFile(std::move(ObjFile));
133   Buffers.push_back(std::move(MemBuf));
134 }
135 
136 void MCJIT::addArchive(object::OwningBinary<object::Archive> A) {
137   Archives.push_back(std::move(A));
138 }
139 
140 void MCJIT::setObjectCache(ObjectCache* NewCache) {
141   std::lock_guard<sys::Mutex> locked(lock);
142   ObjCache = NewCache;
143 }
144 
145 std::unique_ptr<MemoryBuffer> MCJIT::emitObject(Module *M) {
146   assert(M && "Can not emit a null module");
147 
148   std::lock_guard<sys::Mutex> locked(lock);
149 
150   // Materialize all globals in the module if they have not been
151   // materialized already.
152   cantFail(M->materializeAll());
153 
154   // This must be a module which has already been added but not loaded to this
155   // MCJIT instance, since these conditions are tested by our caller,
156   // generateCodeForModule.
157 
158   legacy::PassManager PM;
159 
160   // The RuntimeDyld will take ownership of this shortly
161   SmallVector<char, 4096> ObjBufferSV;
162   raw_svector_ostream ObjStream(ObjBufferSV);
163 
164   // Turn the machine code intermediate representation into bytes in memory
165   // that may be executed.
166   if (TM->addPassesToEmitMC(PM, Ctx, ObjStream, !getVerifyModules()))
167     report_fatal_error("Target does not support MC emission!");
168 
169   // Initialize passes.
170   PM.run(*M);
171   // Flush the output buffer to get the generated code into memory
172 
173   std::unique_ptr<MemoryBuffer> CompiledObjBuffer(
174       new SmallVectorMemoryBuffer(std::move(ObjBufferSV)));
175 
176   // If we have an object cache, tell it about the new object.
177   // Note that we're using the compiled image, not the loaded image (as below).
178   if (ObjCache) {
179     // MemoryBuffer is a thin wrapper around the actual memory, so it's OK
180     // to create a temporary object here and delete it after the call.
181     MemoryBufferRef MB = CompiledObjBuffer->getMemBufferRef();
182     ObjCache->notifyObjectCompiled(M, MB);
183   }
184 
185   return CompiledObjBuffer;
186 }
187 
188 void MCJIT::generateCodeForModule(Module *M) {
189   // Get a thread lock to make sure we aren't trying to load multiple times
190   std::lock_guard<sys::Mutex> locked(lock);
191 
192   // This must be a module which has already been added to this MCJIT instance.
193   assert(OwnedModules.ownsModule(M) &&
194          "MCJIT::generateCodeForModule: Unknown module.");
195 
196   // Re-compilation is not supported
197   if (OwnedModules.hasModuleBeenLoaded(M))
198     return;
199 
200   std::unique_ptr<MemoryBuffer> ObjectToLoad;
201   // Try to load the pre-compiled object from cache if possible
202   if (ObjCache)
203     ObjectToLoad = ObjCache->getObject(M);
204 
205   assert(M->getDataLayout() == getDataLayout() && "DataLayout Mismatch");
206 
207   // If the cache did not contain a suitable object, compile the object
208   if (!ObjectToLoad) {
209     ObjectToLoad = emitObject(M);
210     assert(ObjectToLoad && "Compilation did not produce an object.");
211   }
212 
213   // Load the object into the dynamic linker.
214   // MCJIT now owns the ObjectImage pointer (via its LoadedObjects list).
215   Expected<std::unique_ptr<object::ObjectFile>> LoadedObject =
216     object::ObjectFile::createObjectFile(ObjectToLoad->getMemBufferRef());
217   if (!LoadedObject) {
218     std::string Buf;
219     raw_string_ostream OS(Buf);
220     logAllUnhandledErrors(LoadedObject.takeError(), OS);
221     OS.flush();
222     report_fatal_error(Buf);
223   }
224   std::unique_ptr<RuntimeDyld::LoadedObjectInfo> L =
225     Dyld.loadObject(*LoadedObject.get());
226 
227   if (Dyld.hasError())
228     report_fatal_error(Dyld.getErrorString());
229 
230   notifyObjectLoaded(*LoadedObject.get(), *L);
231 
232   Buffers.push_back(std::move(ObjectToLoad));
233   LoadedObjects.push_back(std::move(*LoadedObject));
234 
235   OwnedModules.markModuleAsLoaded(M);
236 }
237 
238 void MCJIT::finalizeLoadedModules() {
239   std::lock_guard<sys::Mutex> locked(lock);
240 
241   // Resolve any outstanding relocations.
242   Dyld.resolveRelocations();
243 
244   // Check for Dyld error.
245   if (Dyld.hasError())
246     ErrMsg = Dyld.getErrorString().str();
247 
248   OwnedModules.markAllLoadedModulesAsFinalized();
249 
250   // Register EH frame data for any module we own which has been loaded
251   Dyld.registerEHFrames();
252 
253   // Set page permissions.
254   MemMgr->finalizeMemory();
255 }
256 
257 // FIXME: Rename this.
258 void MCJIT::finalizeObject() {
259   std::lock_guard<sys::Mutex> locked(lock);
260 
261   // Generate code for module is going to move objects out of the 'added' list,
262   // so we need to copy that out before using it:
263   SmallVector<Module*, 16> ModsToAdd;
264   for (auto M : OwnedModules.added())
265     ModsToAdd.push_back(M);
266 
267   for (auto M : ModsToAdd)
268     generateCodeForModule(M);
269 
270   finalizeLoadedModules();
271 }
272 
273 void MCJIT::finalizeModule(Module *M) {
274   std::lock_guard<sys::Mutex> locked(lock);
275 
276   // This must be a module which has already been added to this MCJIT instance.
277   assert(OwnedModules.ownsModule(M) && "MCJIT::finalizeModule: Unknown module.");
278 
279   // If the module hasn't been compiled, just do that.
280   if (!OwnedModules.hasModuleBeenLoaded(M))
281     generateCodeForModule(M);
282 
283   finalizeLoadedModules();
284 }
285 
286 JITSymbol MCJIT::findExistingSymbol(const std::string &Name) {
287   if (void *Addr = getPointerToGlobalIfAvailable(Name))
288     return JITSymbol(static_cast<uint64_t>(
289                          reinterpret_cast<uintptr_t>(Addr)),
290                      JITSymbolFlags::Exported);
291 
292   return Dyld.getSymbol(Name);
293 }
294 
295 Module *MCJIT::findModuleForSymbol(const std::string &Name,
296                                    bool CheckFunctionsOnly) {
297   StringRef DemangledName = Name;
298   if (DemangledName[0] == getDataLayout().getGlobalPrefix())
299     DemangledName = DemangledName.substr(1);
300 
301   std::lock_guard<sys::Mutex> locked(lock);
302 
303   // If it hasn't already been generated, see if it's in one of our modules.
304   for (ModulePtrSet::iterator I = OwnedModules.begin_added(),
305                               E = OwnedModules.end_added();
306        I != E; ++I) {
307     Module *M = *I;
308     Function *F = M->getFunction(DemangledName);
309     if (F && !F->isDeclaration())
310       return M;
311     if (!CheckFunctionsOnly) {
312       GlobalVariable *G = M->getGlobalVariable(DemangledName);
313       if (G && !G->isDeclaration())
314         return M;
315       // FIXME: Do we need to worry about global aliases?
316     }
317   }
318   // We didn't find the symbol in any of our modules.
319   return nullptr;
320 }
321 
322 uint64_t MCJIT::getSymbolAddress(const std::string &Name,
323                                  bool CheckFunctionsOnly) {
324   std::string MangledName;
325   {
326     raw_string_ostream MangledNameStream(MangledName);
327     Mangler::getNameWithPrefix(MangledNameStream, Name, getDataLayout());
328   }
329   if (auto Sym = findSymbol(MangledName, CheckFunctionsOnly)) {
330     if (auto AddrOrErr = Sym.getAddress())
331       return *AddrOrErr;
332     else
333       report_fatal_error(AddrOrErr.takeError());
334   } else if (auto Err = Sym.takeError())
335     report_fatal_error(Sym.takeError());
336   return 0;
337 }
338 
339 JITSymbol MCJIT::findSymbol(const std::string &Name,
340                             bool CheckFunctionsOnly) {
341   std::lock_guard<sys::Mutex> locked(lock);
342 
343   // First, check to see if we already have this symbol.
344   if (auto Sym = findExistingSymbol(Name))
345     return Sym;
346 
347   for (object::OwningBinary<object::Archive> &OB : Archives) {
348     object::Archive *A = OB.getBinary();
349     // Look for our symbols in each Archive
350     auto OptionalChildOrErr = A->findSym(Name);
351     if (!OptionalChildOrErr)
352       report_fatal_error(OptionalChildOrErr.takeError());
353     auto &OptionalChild = *OptionalChildOrErr;
354     if (OptionalChild) {
355       // FIXME: Support nested archives?
356       Expected<std::unique_ptr<object::Binary>> ChildBinOrErr =
357           OptionalChild->getAsBinary();
358       if (!ChildBinOrErr) {
359         // TODO: Actually report errors helpfully.
360         consumeError(ChildBinOrErr.takeError());
361         continue;
362       }
363       std::unique_ptr<object::Binary> &ChildBin = ChildBinOrErr.get();
364       if (ChildBin->isObject()) {
365         std::unique_ptr<object::ObjectFile> OF(
366             static_cast<object::ObjectFile *>(ChildBin.release()));
367         // This causes the object file to be loaded.
368         addObjectFile(std::move(OF));
369         // The address should be here now.
370         if (auto Sym = findExistingSymbol(Name))
371           return Sym;
372       }
373     }
374   }
375 
376   // If it hasn't already been generated, see if it's in one of our modules.
377   Module *M = findModuleForSymbol(Name, CheckFunctionsOnly);
378   if (M) {
379     generateCodeForModule(M);
380 
381     // Check the RuntimeDyld table again, it should be there now.
382     return findExistingSymbol(Name);
383   }
384 
385   // If a LazyFunctionCreator is installed, use it to get/create the function.
386   // FIXME: Should we instead have a LazySymbolCreator callback?
387   if (LazyFunctionCreator) {
388     auto Addr = static_cast<uint64_t>(
389                   reinterpret_cast<uintptr_t>(LazyFunctionCreator(Name)));
390     return JITSymbol(Addr, JITSymbolFlags::Exported);
391   }
392 
393   return nullptr;
394 }
395 
396 uint64_t MCJIT::getGlobalValueAddress(const std::string &Name) {
397   std::lock_guard<sys::Mutex> locked(lock);
398   uint64_t Result = getSymbolAddress(Name, false);
399   if (Result != 0)
400     finalizeLoadedModules();
401   return Result;
402 }
403 
404 uint64_t MCJIT::getFunctionAddress(const std::string &Name) {
405   std::lock_guard<sys::Mutex> locked(lock);
406   uint64_t Result = getSymbolAddress(Name, true);
407   if (Result != 0)
408     finalizeLoadedModules();
409   return Result;
410 }
411 
412 // Deprecated.  Use getFunctionAddress instead.
413 void *MCJIT::getPointerToFunction(Function *F) {
414   std::lock_guard<sys::Mutex> locked(lock);
415 
416   Mangler Mang;
417   SmallString<128> Name;
418   TM->getNameWithPrefix(Name, F, Mang);
419 
420   if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
421     bool AbortOnFailure = !F->hasExternalWeakLinkage();
422     void *Addr = getPointerToNamedFunction(Name, AbortOnFailure);
423     updateGlobalMapping(F, Addr);
424     return Addr;
425   }
426 
427   Module *M = F->getParent();
428   bool HasBeenAddedButNotLoaded = OwnedModules.hasModuleBeenAddedButNotLoaded(M);
429 
430   // Make sure the relevant module has been compiled and loaded.
431   if (HasBeenAddedButNotLoaded)
432     generateCodeForModule(M);
433   else if (!OwnedModules.hasModuleBeenLoaded(M)) {
434     // If this function doesn't belong to one of our modules, we're done.
435     // FIXME: Asking for the pointer to a function that hasn't been registered,
436     //        and isn't a declaration (which is handled above) should probably
437     //        be an assertion.
438     return nullptr;
439   }
440 
441   // FIXME: Should the Dyld be retaining module information? Probably not.
442   //
443   // This is the accessor for the target address, so make sure to check the
444   // load address of the symbol, not the local address.
445   return (void*)Dyld.getSymbol(Name).getAddress();
446 }
447 
448 void MCJIT::runStaticConstructorsDestructorsInModulePtrSet(
449     bool isDtors, ModulePtrSet::iterator I, ModulePtrSet::iterator E) {
450   for (; I != E; ++I) {
451     ExecutionEngine::runStaticConstructorsDestructors(**I, isDtors);
452   }
453 }
454 
455 void MCJIT::runStaticConstructorsDestructors(bool isDtors) {
456   // Execute global ctors/dtors for each module in the program.
457   runStaticConstructorsDestructorsInModulePtrSet(
458       isDtors, OwnedModules.begin_added(), OwnedModules.end_added());
459   runStaticConstructorsDestructorsInModulePtrSet(
460       isDtors, OwnedModules.begin_loaded(), OwnedModules.end_loaded());
461   runStaticConstructorsDestructorsInModulePtrSet(
462       isDtors, OwnedModules.begin_finalized(), OwnedModules.end_finalized());
463 }
464 
465 Function *MCJIT::FindFunctionNamedInModulePtrSet(StringRef FnName,
466                                                  ModulePtrSet::iterator I,
467                                                  ModulePtrSet::iterator E) {
468   for (; I != E; ++I) {
469     Function *F = (*I)->getFunction(FnName);
470     if (F && !F->isDeclaration())
471       return F;
472   }
473   return nullptr;
474 }
475 
476 GlobalVariable *MCJIT::FindGlobalVariableNamedInModulePtrSet(StringRef Name,
477                                                              bool AllowInternal,
478                                                              ModulePtrSet::iterator I,
479                                                              ModulePtrSet::iterator E) {
480   for (; I != E; ++I) {
481     GlobalVariable *GV = (*I)->getGlobalVariable(Name, AllowInternal);
482     if (GV && !GV->isDeclaration())
483       return GV;
484   }
485   return nullptr;
486 }
487 
488 
489 Function *MCJIT::FindFunctionNamed(StringRef FnName) {
490   Function *F = FindFunctionNamedInModulePtrSet(
491       FnName, OwnedModules.begin_added(), OwnedModules.end_added());
492   if (!F)
493     F = FindFunctionNamedInModulePtrSet(FnName, OwnedModules.begin_loaded(),
494                                         OwnedModules.end_loaded());
495   if (!F)
496     F = FindFunctionNamedInModulePtrSet(FnName, OwnedModules.begin_finalized(),
497                                         OwnedModules.end_finalized());
498   return F;
499 }
500 
501 GlobalVariable *MCJIT::FindGlobalVariableNamed(StringRef Name, bool AllowInternal) {
502   GlobalVariable *GV = FindGlobalVariableNamedInModulePtrSet(
503       Name, AllowInternal, OwnedModules.begin_added(), OwnedModules.end_added());
504   if (!GV)
505     GV = FindGlobalVariableNamedInModulePtrSet(Name, AllowInternal, OwnedModules.begin_loaded(),
506                                         OwnedModules.end_loaded());
507   if (!GV)
508     GV = FindGlobalVariableNamedInModulePtrSet(Name, AllowInternal, OwnedModules.begin_finalized(),
509                                         OwnedModules.end_finalized());
510   return GV;
511 }
512 
513 GenericValue MCJIT::runFunction(Function *F, ArrayRef<GenericValue> ArgValues) {
514   assert(F && "Function *F was null at entry to run()");
515 
516   void *FPtr = getPointerToFunction(F);
517   finalizeModule(F->getParent());
518   assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
519   FunctionType *FTy = F->getFunctionType();
520   Type *RetTy = FTy->getReturnType();
521 
522   assert((FTy->getNumParams() == ArgValues.size() ||
523           (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
524          "Wrong number of arguments passed into function!");
525   assert(FTy->getNumParams() == ArgValues.size() &&
526          "This doesn't support passing arguments through varargs (yet)!");
527 
528   // Handle some common cases first.  These cases correspond to common `main'
529   // prototypes.
530   if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
531     switch (ArgValues.size()) {
532     case 3:
533       if (FTy->getParamType(0)->isIntegerTy(32) &&
534           FTy->getParamType(1)->isPointerTy() &&
535           FTy->getParamType(2)->isPointerTy()) {
536         int (*PF)(int, char **, const char **) =
537           (int(*)(int, char **, const char **))(intptr_t)FPtr;
538 
539         // Call the function.
540         GenericValue rv;
541         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
542                                  (char **)GVTOP(ArgValues[1]),
543                                  (const char **)GVTOP(ArgValues[2])));
544         return rv;
545       }
546       break;
547     case 2:
548       if (FTy->getParamType(0)->isIntegerTy(32) &&
549           FTy->getParamType(1)->isPointerTy()) {
550         int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
551 
552         // Call the function.
553         GenericValue rv;
554         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
555                                  (char **)GVTOP(ArgValues[1])));
556         return rv;
557       }
558       break;
559     case 1:
560       if (FTy->getNumParams() == 1 &&
561           FTy->getParamType(0)->isIntegerTy(32)) {
562         GenericValue rv;
563         int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
564         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
565         return rv;
566       }
567       break;
568     }
569   }
570 
571   // Handle cases where no arguments are passed first.
572   if (ArgValues.empty()) {
573     GenericValue rv;
574     switch (RetTy->getTypeID()) {
575     default: llvm_unreachable("Unknown return type for function call!");
576     case Type::IntegerTyID: {
577       unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
578       if (BitWidth == 1)
579         rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
580       else if (BitWidth <= 8)
581         rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
582       else if (BitWidth <= 16)
583         rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
584       else if (BitWidth <= 32)
585         rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
586       else if (BitWidth <= 64)
587         rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
588       else
589         llvm_unreachable("Integer types > 64 bits not supported");
590       return rv;
591     }
592     case Type::VoidTyID:
593       rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
594       return rv;
595     case Type::FloatTyID:
596       rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
597       return rv;
598     case Type::DoubleTyID:
599       rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
600       return rv;
601     case Type::X86_FP80TyID:
602     case Type::FP128TyID:
603     case Type::PPC_FP128TyID:
604       llvm_unreachable("long double not supported yet");
605     case Type::PointerTyID:
606       return PTOGV(((void*(*)())(intptr_t)FPtr)());
607     }
608   }
609 
610   report_fatal_error("MCJIT::runFunction does not support full-featured "
611                      "argument passing. Please use "
612                      "ExecutionEngine::getFunctionAddress and cast the result "
613                      "to the desired function pointer type.");
614 }
615 
616 void *MCJIT::getPointerToNamedFunction(StringRef Name, bool AbortOnFailure) {
617   if (!isSymbolSearchingDisabled()) {
618     if (auto Sym = Resolver.findSymbol(std::string(Name))) {
619       if (auto AddrOrErr = Sym.getAddress())
620         return reinterpret_cast<void*>(
621                  static_cast<uintptr_t>(*AddrOrErr));
622     } else if (auto Err = Sym.takeError())
623       report_fatal_error(std::move(Err));
624   }
625 
626   /// If a LazyFunctionCreator is installed, use it to get/create the function.
627   if (LazyFunctionCreator)
628     if (void *RP = LazyFunctionCreator(std::string(Name)))
629       return RP;
630 
631   if (AbortOnFailure) {
632     report_fatal_error("Program used external function '"+Name+
633                        "' which could not be resolved!");
634   }
635   return nullptr;
636 }
637 
638 void MCJIT::RegisterJITEventListener(JITEventListener *L) {
639   if (!L)
640     return;
641   std::lock_guard<sys::Mutex> locked(lock);
642   EventListeners.push_back(L);
643 }
644 
645 void MCJIT::UnregisterJITEventListener(JITEventListener *L) {
646   if (!L)
647     return;
648   std::lock_guard<sys::Mutex> locked(lock);
649   auto I = find(reverse(EventListeners), L);
650   if (I != EventListeners.rend()) {
651     std::swap(*I, EventListeners.back());
652     EventListeners.pop_back();
653   }
654 }
655 
656 void MCJIT::notifyObjectLoaded(const object::ObjectFile &Obj,
657                                const RuntimeDyld::LoadedObjectInfo &L) {
658   uint64_t Key =
659       static_cast<uint64_t>(reinterpret_cast<uintptr_t>(Obj.getData().data()));
660   std::lock_guard<sys::Mutex> locked(lock);
661   MemMgr->notifyObjectLoaded(this, Obj);
662   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
663     EventListeners[I]->notifyObjectLoaded(Key, Obj, L);
664   }
665 }
666 
667 void MCJIT::notifyFreeingObject(const object::ObjectFile &Obj) {
668   uint64_t Key =
669       static_cast<uint64_t>(reinterpret_cast<uintptr_t>(Obj.getData().data()));
670   std::lock_guard<sys::Mutex> locked(lock);
671   for (JITEventListener *L : EventListeners)
672     L->notifyFreeingObject(Key);
673 }
674 
675 JITSymbol
676 LinkingSymbolResolver::findSymbol(const std::string &Name) {
677   auto Result = ParentEngine.findSymbol(Name, false);
678   if (Result)
679     return Result;
680   if (ParentEngine.isSymbolSearchingDisabled())
681     return nullptr;
682   return ClientResolver->findSymbol(Name);
683 }
684 
685 void LinkingSymbolResolver::anchor() {}
686