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1 //===-- ExecutionEngine.cpp - Common Implementation shared by EEs ---------===//
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 // This file defines the common interface used by the various execution engine
11 // subclasses.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/ExecutionEngine/ExecutionEngine.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/ADT/SmallString.h"
18 #include "llvm/ADT/Statistic.h"
19 #include "llvm/ExecutionEngine/GenericValue.h"
20 #include "llvm/ExecutionEngine/JITEventListener.h"
21 #include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/IR/DataLayout.h"
24 #include "llvm/IR/DerivedTypes.h"
25 #include "llvm/IR/Mangler.h"
26 #include "llvm/IR/Module.h"
27 #include "llvm/IR/Operator.h"
28 #include "llvm/IR/ValueHandle.h"
29 #include "llvm/Object/Archive.h"
30 #include "llvm/Object/ObjectFile.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/DynamicLibrary.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/Host.h"
35 #include "llvm/Support/MutexGuard.h"
36 #include "llvm/Support/TargetRegistry.h"
37 #include "llvm/Support/raw_ostream.h"
38 #include "llvm/Target/TargetMachine.h"
39 #include <cmath>
40 #include <cstring>
41 using namespace llvm;
42 
43 #define DEBUG_TYPE "jit"
44 
45 STATISTIC(NumInitBytes, "Number of bytes of global vars initialized");
46 STATISTIC(NumGlobals  , "Number of global vars initialized");
47 
48 ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
49     std::unique_ptr<Module> M, std::string *ErrorStr,
50     std::shared_ptr<MCJITMemoryManager> MemMgr,
51     std::shared_ptr<RuntimeDyld::SymbolResolver> Resolver,
52     std::unique_ptr<TargetMachine> TM) = nullptr;
53 
54 ExecutionEngine *(*ExecutionEngine::OrcMCJITReplacementCtor)(
55   std::string *ErrorStr, std::shared_ptr<MCJITMemoryManager> MemMgr,
56   std::shared_ptr<RuntimeDyld::SymbolResolver> Resolver,
57   std::unique_ptr<TargetMachine> TM) = nullptr;
58 
59 ExecutionEngine *(*ExecutionEngine::InterpCtor)(std::unique_ptr<Module> M,
60                                                 std::string *ErrorStr) =nullptr;
61 
anchor()62 void JITEventListener::anchor() {}
63 
Init(std::unique_ptr<Module> M)64 void ExecutionEngine::Init(std::unique_ptr<Module> M) {
65   CompilingLazily         = false;
66   GVCompilationDisabled   = false;
67   SymbolSearchingDisabled = false;
68 
69   // IR module verification is enabled by default in debug builds, and disabled
70   // by default in release builds.
71 #ifndef NDEBUG
72   VerifyModules = true;
73 #else
74   VerifyModules = false;
75 #endif
76 
77   assert(M && "Module is null?");
78   Modules.push_back(std::move(M));
79 }
80 
ExecutionEngine(std::unique_ptr<Module> M)81 ExecutionEngine::ExecutionEngine(std::unique_ptr<Module> M)
82     : DL(M->getDataLayout()), LazyFunctionCreator(nullptr) {
83   Init(std::move(M));
84 }
85 
ExecutionEngine(DataLayout DL,std::unique_ptr<Module> M)86 ExecutionEngine::ExecutionEngine(DataLayout DL, std::unique_ptr<Module> M)
87     : DL(std::move(DL)), LazyFunctionCreator(nullptr) {
88   Init(std::move(M));
89 }
90 
~ExecutionEngine()91 ExecutionEngine::~ExecutionEngine() {
92   clearAllGlobalMappings();
93 }
94 
95 namespace {
96 /// \brief Helper class which uses a value handler to automatically deletes the
97 /// memory block when the GlobalVariable is destroyed.
98 class GVMemoryBlock final : public CallbackVH {
GVMemoryBlock(const GlobalVariable * GV)99   GVMemoryBlock(const GlobalVariable *GV)
100     : CallbackVH(const_cast<GlobalVariable*>(GV)) {}
101 
102 public:
103   /// \brief Returns the address the GlobalVariable should be written into.  The
104   /// GVMemoryBlock object prefixes that.
Create(const GlobalVariable * GV,const DataLayout & TD)105   static char *Create(const GlobalVariable *GV, const DataLayout& TD) {
106     Type *ElTy = GV->getValueType();
107     size_t GVSize = (size_t)TD.getTypeAllocSize(ElTy);
108     void *RawMemory = ::operator new(
109         alignTo(sizeof(GVMemoryBlock), TD.getPreferredAlignment(GV)) + GVSize);
110     new(RawMemory) GVMemoryBlock(GV);
111     return static_cast<char*>(RawMemory) + sizeof(GVMemoryBlock);
112   }
113 
deleted()114   void deleted() override {
115     // We allocated with operator new and with some extra memory hanging off the
116     // end, so don't just delete this.  I'm not sure if this is actually
117     // required.
118     this->~GVMemoryBlock();
119     ::operator delete(this);
120   }
121 };
122 }  // anonymous namespace
123 
getMemoryForGV(const GlobalVariable * GV)124 char *ExecutionEngine::getMemoryForGV(const GlobalVariable *GV) {
125   return GVMemoryBlock::Create(GV, getDataLayout());
126 }
127 
addObjectFile(std::unique_ptr<object::ObjectFile> O)128 void ExecutionEngine::addObjectFile(std::unique_ptr<object::ObjectFile> O) {
129   llvm_unreachable("ExecutionEngine subclass doesn't implement addObjectFile.");
130 }
131 
132 void
addObjectFile(object::OwningBinary<object::ObjectFile> O)133 ExecutionEngine::addObjectFile(object::OwningBinary<object::ObjectFile> O) {
134   llvm_unreachable("ExecutionEngine subclass doesn't implement addObjectFile.");
135 }
136 
addArchive(object::OwningBinary<object::Archive> A)137 void ExecutionEngine::addArchive(object::OwningBinary<object::Archive> A) {
138   llvm_unreachable("ExecutionEngine subclass doesn't implement addArchive.");
139 }
140 
removeModule(Module * M)141 bool ExecutionEngine::removeModule(Module *M) {
142   for (auto I = Modules.begin(), E = Modules.end(); I != E; ++I) {
143     Module *Found = I->get();
144     if (Found == M) {
145       I->release();
146       Modules.erase(I);
147       clearGlobalMappingsFromModule(M);
148       return true;
149     }
150   }
151   return false;
152 }
153 
FindFunctionNamed(const char * FnName)154 Function *ExecutionEngine::FindFunctionNamed(const char *FnName) {
155   for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
156     Function *F = Modules[i]->getFunction(FnName);
157     if (F && !F->isDeclaration())
158       return F;
159   }
160   return nullptr;
161 }
162 
FindGlobalVariableNamed(const char * Name,bool AllowInternal)163 GlobalVariable *ExecutionEngine::FindGlobalVariableNamed(const char *Name, bool AllowInternal) {
164   for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
165     GlobalVariable *GV = Modules[i]->getGlobalVariable(Name,AllowInternal);
166     if (GV && !GV->isDeclaration())
167       return GV;
168   }
169   return nullptr;
170 }
171 
RemoveMapping(StringRef Name)172 uint64_t ExecutionEngineState::RemoveMapping(StringRef Name) {
173   GlobalAddressMapTy::iterator I = GlobalAddressMap.find(Name);
174   uint64_t OldVal;
175 
176   // FIXME: This is silly, we shouldn't end up with a mapping -> 0 in the
177   // GlobalAddressMap.
178   if (I == GlobalAddressMap.end())
179     OldVal = 0;
180   else {
181     GlobalAddressReverseMap.erase(I->second);
182     OldVal = I->second;
183     GlobalAddressMap.erase(I);
184   }
185 
186   return OldVal;
187 }
188 
getMangledName(const GlobalValue * GV)189 std::string ExecutionEngine::getMangledName(const GlobalValue *GV) {
190   assert(GV->hasName() && "Global must have name.");
191 
192   MutexGuard locked(lock);
193   SmallString<128> FullName;
194 
195   const DataLayout &DL =
196     GV->getParent()->getDataLayout().isDefault()
197       ? getDataLayout()
198       : GV->getParent()->getDataLayout();
199 
200   Mangler::getNameWithPrefix(FullName, GV->getName(), DL);
201   return FullName.str();
202 }
203 
addGlobalMapping(const GlobalValue * GV,void * Addr)204 void ExecutionEngine::addGlobalMapping(const GlobalValue *GV, void *Addr) {
205   MutexGuard locked(lock);
206   addGlobalMapping(getMangledName(GV), (uint64_t) Addr);
207 }
208 
addGlobalMapping(StringRef Name,uint64_t Addr)209 void ExecutionEngine::addGlobalMapping(StringRef Name, uint64_t Addr) {
210   MutexGuard locked(lock);
211 
212   assert(!Name.empty() && "Empty GlobalMapping symbol name!");
213 
214   DEBUG(dbgs() << "JIT: Map \'" << Name  << "\' to [" << Addr << "]\n";);
215   uint64_t &CurVal = EEState.getGlobalAddressMap()[Name];
216   assert((!CurVal || !Addr) && "GlobalMapping already established!");
217   CurVal = Addr;
218 
219   // If we are using the reverse mapping, add it too.
220   if (!EEState.getGlobalAddressReverseMap().empty()) {
221     std::string &V = EEState.getGlobalAddressReverseMap()[CurVal];
222     assert((!V.empty() || !Name.empty()) &&
223            "GlobalMapping already established!");
224     V = Name;
225   }
226 }
227 
clearAllGlobalMappings()228 void ExecutionEngine::clearAllGlobalMappings() {
229   MutexGuard locked(lock);
230 
231   EEState.getGlobalAddressMap().clear();
232   EEState.getGlobalAddressReverseMap().clear();
233 }
234 
clearGlobalMappingsFromModule(Module * M)235 void ExecutionEngine::clearGlobalMappingsFromModule(Module *M) {
236   MutexGuard locked(lock);
237 
238   for (GlobalObject &GO : M->global_objects())
239     EEState.RemoveMapping(getMangledName(&GO));
240 }
241 
updateGlobalMapping(const GlobalValue * GV,void * Addr)242 uint64_t ExecutionEngine::updateGlobalMapping(const GlobalValue *GV,
243                                               void *Addr) {
244   MutexGuard locked(lock);
245   return updateGlobalMapping(getMangledName(GV), (uint64_t) Addr);
246 }
247 
updateGlobalMapping(StringRef Name,uint64_t Addr)248 uint64_t ExecutionEngine::updateGlobalMapping(StringRef Name, uint64_t Addr) {
249   MutexGuard locked(lock);
250 
251   ExecutionEngineState::GlobalAddressMapTy &Map =
252     EEState.getGlobalAddressMap();
253 
254   // Deleting from the mapping?
255   if (!Addr)
256     return EEState.RemoveMapping(Name);
257 
258   uint64_t &CurVal = Map[Name];
259   uint64_t OldVal = CurVal;
260 
261   if (CurVal && !EEState.getGlobalAddressReverseMap().empty())
262     EEState.getGlobalAddressReverseMap().erase(CurVal);
263   CurVal = Addr;
264 
265   // If we are using the reverse mapping, add it too.
266   if (!EEState.getGlobalAddressReverseMap().empty()) {
267     std::string &V = EEState.getGlobalAddressReverseMap()[CurVal];
268     assert((!V.empty() || !Name.empty()) &&
269            "GlobalMapping already established!");
270     V = Name;
271   }
272   return OldVal;
273 }
274 
getAddressToGlobalIfAvailable(StringRef S)275 uint64_t ExecutionEngine::getAddressToGlobalIfAvailable(StringRef S) {
276   MutexGuard locked(lock);
277   uint64_t Address = 0;
278   ExecutionEngineState::GlobalAddressMapTy::iterator I =
279     EEState.getGlobalAddressMap().find(S);
280   if (I != EEState.getGlobalAddressMap().end())
281     Address = I->second;
282   return Address;
283 }
284 
285 
getPointerToGlobalIfAvailable(StringRef S)286 void *ExecutionEngine::getPointerToGlobalIfAvailable(StringRef S) {
287   MutexGuard locked(lock);
288   if (void* Address = (void *) getAddressToGlobalIfAvailable(S))
289     return Address;
290   return nullptr;
291 }
292 
getPointerToGlobalIfAvailable(const GlobalValue * GV)293 void *ExecutionEngine::getPointerToGlobalIfAvailable(const GlobalValue *GV) {
294   MutexGuard locked(lock);
295   return getPointerToGlobalIfAvailable(getMangledName(GV));
296 }
297 
getGlobalValueAtAddress(void * Addr)298 const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
299   MutexGuard locked(lock);
300 
301   // If we haven't computed the reverse mapping yet, do so first.
302   if (EEState.getGlobalAddressReverseMap().empty()) {
303     for (ExecutionEngineState::GlobalAddressMapTy::iterator
304            I = EEState.getGlobalAddressMap().begin(),
305            E = EEState.getGlobalAddressMap().end(); I != E; ++I) {
306       StringRef Name = I->first();
307       uint64_t Addr = I->second;
308       EEState.getGlobalAddressReverseMap().insert(std::make_pair(
309                                                           Addr, Name));
310     }
311   }
312 
313   std::map<uint64_t, std::string>::iterator I =
314     EEState.getGlobalAddressReverseMap().find((uint64_t) Addr);
315 
316   if (I != EEState.getGlobalAddressReverseMap().end()) {
317     StringRef Name = I->second;
318     for (unsigned i = 0, e = Modules.size(); i != e; ++i)
319       if (GlobalValue *GV = Modules[i]->getNamedValue(Name))
320         return GV;
321   }
322   return nullptr;
323 }
324 
325 namespace {
326 class ArgvArray {
327   std::unique_ptr<char[]> Array;
328   std::vector<std::unique_ptr<char[]>> Values;
329 public:
330   /// Turn a vector of strings into a nice argv style array of pointers to null
331   /// terminated strings.
332   void *reset(LLVMContext &C, ExecutionEngine *EE,
333               const std::vector<std::string> &InputArgv);
334 };
335 }  // anonymous namespace
reset(LLVMContext & C,ExecutionEngine * EE,const std::vector<std::string> & InputArgv)336 void *ArgvArray::reset(LLVMContext &C, ExecutionEngine *EE,
337                        const std::vector<std::string> &InputArgv) {
338   Values.clear();  // Free the old contents.
339   Values.reserve(InputArgv.size());
340   unsigned PtrSize = EE->getDataLayout().getPointerSize();
341   Array = make_unique<char[]>((InputArgv.size()+1)*PtrSize);
342 
343   DEBUG(dbgs() << "JIT: ARGV = " << (void*)Array.get() << "\n");
344   Type *SBytePtr = Type::getInt8PtrTy(C);
345 
346   for (unsigned i = 0; i != InputArgv.size(); ++i) {
347     unsigned Size = InputArgv[i].size()+1;
348     auto Dest = make_unique<char[]>(Size);
349     DEBUG(dbgs() << "JIT: ARGV[" << i << "] = " << (void*)Dest.get() << "\n");
350 
351     std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest.get());
352     Dest[Size-1] = 0;
353 
354     // Endian safe: Array[i] = (PointerTy)Dest;
355     EE->StoreValueToMemory(PTOGV(Dest.get()),
356                            (GenericValue*)(&Array[i*PtrSize]), SBytePtr);
357     Values.push_back(std::move(Dest));
358   }
359 
360   // Null terminate it
361   EE->StoreValueToMemory(PTOGV(nullptr),
362                          (GenericValue*)(&Array[InputArgv.size()*PtrSize]),
363                          SBytePtr);
364   return Array.get();
365 }
366 
runStaticConstructorsDestructors(Module & module,bool isDtors)367 void ExecutionEngine::runStaticConstructorsDestructors(Module &module,
368                                                        bool isDtors) {
369   const char *Name = isDtors ? "llvm.global_dtors" : "llvm.global_ctors";
370   GlobalVariable *GV = module.getNamedGlobal(Name);
371 
372   // If this global has internal linkage, or if it has a use, then it must be
373   // an old-style (llvmgcc3) static ctor with __main linked in and in use.  If
374   // this is the case, don't execute any of the global ctors, __main will do
375   // it.
376   if (!GV || GV->isDeclaration() || GV->hasLocalLinkage()) return;
377 
378   // Should be an array of '{ i32, void ()* }' structs.  The first value is
379   // the init priority, which we ignore.
380   ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
381   if (!InitList)
382     return;
383   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
384     ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i));
385     if (!CS) continue;
386 
387     Constant *FP = CS->getOperand(1);
388     if (FP->isNullValue())
389       continue;  // Found a sentinal value, ignore.
390 
391     // Strip off constant expression casts.
392     if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
393       if (CE->isCast())
394         FP = CE->getOperand(0);
395 
396     // Execute the ctor/dtor function!
397     if (Function *F = dyn_cast<Function>(FP))
398       runFunction(F, None);
399 
400     // FIXME: It is marginally lame that we just do nothing here if we see an
401     // entry we don't recognize. It might not be unreasonable for the verifier
402     // to not even allow this and just assert here.
403   }
404 }
405 
runStaticConstructorsDestructors(bool isDtors)406 void ExecutionEngine::runStaticConstructorsDestructors(bool isDtors) {
407   // Execute global ctors/dtors for each module in the program.
408   for (std::unique_ptr<Module> &M : Modules)
409     runStaticConstructorsDestructors(*M, isDtors);
410 }
411 
412 #ifndef NDEBUG
413 /// isTargetNullPtr - Return whether the target pointer stored at Loc is null.
isTargetNullPtr(ExecutionEngine * EE,void * Loc)414 static bool isTargetNullPtr(ExecutionEngine *EE, void *Loc) {
415   unsigned PtrSize = EE->getDataLayout().getPointerSize();
416   for (unsigned i = 0; i < PtrSize; ++i)
417     if (*(i + (uint8_t*)Loc))
418       return false;
419   return true;
420 }
421 #endif
422 
runFunctionAsMain(Function * Fn,const std::vector<std::string> & argv,const char * const * envp)423 int ExecutionEngine::runFunctionAsMain(Function *Fn,
424                                        const std::vector<std::string> &argv,
425                                        const char * const * envp) {
426   std::vector<GenericValue> GVArgs;
427   GenericValue GVArgc;
428   GVArgc.IntVal = APInt(32, argv.size());
429 
430   // Check main() type
431   unsigned NumArgs = Fn->getFunctionType()->getNumParams();
432   FunctionType *FTy = Fn->getFunctionType();
433   Type* PPInt8Ty = Type::getInt8PtrTy(Fn->getContext())->getPointerTo();
434 
435   // Check the argument types.
436   if (NumArgs > 3)
437     report_fatal_error("Invalid number of arguments of main() supplied");
438   if (NumArgs >= 3 && FTy->getParamType(2) != PPInt8Ty)
439     report_fatal_error("Invalid type for third argument of main() supplied");
440   if (NumArgs >= 2 && FTy->getParamType(1) != PPInt8Ty)
441     report_fatal_error("Invalid type for second argument of main() supplied");
442   if (NumArgs >= 1 && !FTy->getParamType(0)->isIntegerTy(32))
443     report_fatal_error("Invalid type for first argument of main() supplied");
444   if (!FTy->getReturnType()->isIntegerTy() &&
445       !FTy->getReturnType()->isVoidTy())
446     report_fatal_error("Invalid return type of main() supplied");
447 
448   ArgvArray CArgv;
449   ArgvArray CEnv;
450   if (NumArgs) {
451     GVArgs.push_back(GVArgc); // Arg #0 = argc.
452     if (NumArgs > 1) {
453       // Arg #1 = argv.
454       GVArgs.push_back(PTOGV(CArgv.reset(Fn->getContext(), this, argv)));
455       assert(!isTargetNullPtr(this, GVTOP(GVArgs[1])) &&
456              "argv[0] was null after CreateArgv");
457       if (NumArgs > 2) {
458         std::vector<std::string> EnvVars;
459         for (unsigned i = 0; envp[i]; ++i)
460           EnvVars.emplace_back(envp[i]);
461         // Arg #2 = envp.
462         GVArgs.push_back(PTOGV(CEnv.reset(Fn->getContext(), this, EnvVars)));
463       }
464     }
465   }
466 
467   return runFunction(Fn, GVArgs).IntVal.getZExtValue();
468 }
469 
EngineBuilder()470 EngineBuilder::EngineBuilder() : EngineBuilder(nullptr) {}
471 
EngineBuilder(std::unique_ptr<Module> M)472 EngineBuilder::EngineBuilder(std::unique_ptr<Module> M)
473     : M(std::move(M)), WhichEngine(EngineKind::Either), ErrorStr(nullptr),
474       OptLevel(CodeGenOpt::Default), MemMgr(nullptr), Resolver(nullptr),
475       CMModel(CodeModel::JITDefault), UseOrcMCJITReplacement(false) {
476 // IR module verification is enabled by default in debug builds, and disabled
477 // by default in release builds.
478 #ifndef NDEBUG
479   VerifyModules = true;
480 #else
481   VerifyModules = false;
482 #endif
483 }
484 
485 EngineBuilder::~EngineBuilder() = default;
486 
setMCJITMemoryManager(std::unique_ptr<RTDyldMemoryManager> mcjmm)487 EngineBuilder &EngineBuilder::setMCJITMemoryManager(
488                                    std::unique_ptr<RTDyldMemoryManager> mcjmm) {
489   auto SharedMM = std::shared_ptr<RTDyldMemoryManager>(std::move(mcjmm));
490   MemMgr = SharedMM;
491   Resolver = SharedMM;
492   return *this;
493 }
494 
495 EngineBuilder&
setMemoryManager(std::unique_ptr<MCJITMemoryManager> MM)496 EngineBuilder::setMemoryManager(std::unique_ptr<MCJITMemoryManager> MM) {
497   MemMgr = std::shared_ptr<MCJITMemoryManager>(std::move(MM));
498   return *this;
499 }
500 
501 EngineBuilder&
setSymbolResolver(std::unique_ptr<RuntimeDyld::SymbolResolver> SR)502 EngineBuilder::setSymbolResolver(std::unique_ptr<RuntimeDyld::SymbolResolver> SR) {
503   Resolver = std::shared_ptr<RuntimeDyld::SymbolResolver>(std::move(SR));
504   return *this;
505 }
506 
create(TargetMachine * TM)507 ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
508   std::unique_ptr<TargetMachine> TheTM(TM); // Take ownership.
509 
510   // Make sure we can resolve symbols in the program as well. The zero arg
511   // to the function tells DynamicLibrary to load the program, not a library.
512   if (sys::DynamicLibrary::LoadLibraryPermanently(nullptr, ErrorStr))
513     return nullptr;
514 
515   // If the user specified a memory manager but didn't specify which engine to
516   // create, we assume they only want the JIT, and we fail if they only want
517   // the interpreter.
518   if (MemMgr) {
519     if (WhichEngine & EngineKind::JIT)
520       WhichEngine = EngineKind::JIT;
521     else {
522       if (ErrorStr)
523         *ErrorStr = "Cannot create an interpreter with a memory manager.";
524       return nullptr;
525     }
526   }
527 
528   // Unless the interpreter was explicitly selected or the JIT is not linked,
529   // try making a JIT.
530   if ((WhichEngine & EngineKind::JIT) && TheTM) {
531     Triple TT(M->getTargetTriple());
532     if (!TM->getTarget().hasJIT()) {
533       errs() << "WARNING: This target JIT is not designed for the host"
534              << " you are running.  If bad things happen, please choose"
535              << " a different -march switch.\n";
536     }
537 
538     ExecutionEngine *EE = nullptr;
539     if (ExecutionEngine::OrcMCJITReplacementCtor && UseOrcMCJITReplacement) {
540       EE = ExecutionEngine::OrcMCJITReplacementCtor(ErrorStr, std::move(MemMgr),
541                                                     std::move(Resolver),
542                                                     std::move(TheTM));
543       EE->addModule(std::move(M));
544     } else if (ExecutionEngine::MCJITCtor)
545       EE = ExecutionEngine::MCJITCtor(std::move(M), ErrorStr, std::move(MemMgr),
546                                       std::move(Resolver), std::move(TheTM));
547 
548     if (EE) {
549       EE->setVerifyModules(VerifyModules);
550       return EE;
551     }
552   }
553 
554   // If we can't make a JIT and we didn't request one specifically, try making
555   // an interpreter instead.
556   if (WhichEngine & EngineKind::Interpreter) {
557     if (ExecutionEngine::InterpCtor)
558       return ExecutionEngine::InterpCtor(std::move(M), ErrorStr);
559     if (ErrorStr)
560       *ErrorStr = "Interpreter has not been linked in.";
561     return nullptr;
562   }
563 
564   if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::MCJITCtor) {
565     if (ErrorStr)
566       *ErrorStr = "JIT has not been linked in.";
567   }
568 
569   return nullptr;
570 }
571 
getPointerToGlobal(const GlobalValue * GV)572 void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
573   if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
574     return getPointerToFunction(F);
575 
576   MutexGuard locked(lock);
577   if (void* P = getPointerToGlobalIfAvailable(GV))
578     return P;
579 
580   // Global variable might have been added since interpreter started.
581   if (GlobalVariable *GVar =
582           const_cast<GlobalVariable *>(dyn_cast<GlobalVariable>(GV)))
583     EmitGlobalVariable(GVar);
584   else
585     llvm_unreachable("Global hasn't had an address allocated yet!");
586 
587   return getPointerToGlobalIfAvailable(GV);
588 }
589 
590 /// \brief Converts a Constant* into a GenericValue, including handling of
591 /// ConstantExpr values.
getConstantValue(const Constant * C)592 GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
593   // If its undefined, return the garbage.
594   if (isa<UndefValue>(C)) {
595     GenericValue Result;
596     switch (C->getType()->getTypeID()) {
597     default:
598       break;
599     case Type::IntegerTyID:
600     case Type::X86_FP80TyID:
601     case Type::FP128TyID:
602     case Type::PPC_FP128TyID:
603       // Although the value is undefined, we still have to construct an APInt
604       // with the correct bit width.
605       Result.IntVal = APInt(C->getType()->getPrimitiveSizeInBits(), 0);
606       break;
607     case Type::StructTyID: {
608       // if the whole struct is 'undef' just reserve memory for the value.
609       if(StructType *STy = dyn_cast<StructType>(C->getType())) {
610         unsigned int elemNum = STy->getNumElements();
611         Result.AggregateVal.resize(elemNum);
612         for (unsigned int i = 0; i < elemNum; ++i) {
613           Type *ElemTy = STy->getElementType(i);
614           if (ElemTy->isIntegerTy())
615             Result.AggregateVal[i].IntVal =
616               APInt(ElemTy->getPrimitiveSizeInBits(), 0);
617           else if (ElemTy->isAggregateType()) {
618               const Constant *ElemUndef = UndefValue::get(ElemTy);
619               Result.AggregateVal[i] = getConstantValue(ElemUndef);
620             }
621           }
622         }
623       }
624       break;
625     case Type::VectorTyID:
626       // if the whole vector is 'undef' just reserve memory for the value.
627       auto* VTy = dyn_cast<VectorType>(C->getType());
628       Type *ElemTy = VTy->getElementType();
629       unsigned int elemNum = VTy->getNumElements();
630       Result.AggregateVal.resize(elemNum);
631       if (ElemTy->isIntegerTy())
632         for (unsigned int i = 0; i < elemNum; ++i)
633           Result.AggregateVal[i].IntVal =
634             APInt(ElemTy->getPrimitiveSizeInBits(), 0);
635       break;
636     }
637     return Result;
638   }
639 
640   // Otherwise, if the value is a ConstantExpr...
641   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
642     Constant *Op0 = CE->getOperand(0);
643     switch (CE->getOpcode()) {
644     case Instruction::GetElementPtr: {
645       // Compute the index
646       GenericValue Result = getConstantValue(Op0);
647       APInt Offset(DL.getPointerSizeInBits(), 0);
648       cast<GEPOperator>(CE)->accumulateConstantOffset(DL, Offset);
649 
650       char* tmp = (char*) Result.PointerVal;
651       Result = PTOGV(tmp + Offset.getSExtValue());
652       return Result;
653     }
654     case Instruction::Trunc: {
655       GenericValue GV = getConstantValue(Op0);
656       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
657       GV.IntVal = GV.IntVal.trunc(BitWidth);
658       return GV;
659     }
660     case Instruction::ZExt: {
661       GenericValue GV = getConstantValue(Op0);
662       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
663       GV.IntVal = GV.IntVal.zext(BitWidth);
664       return GV;
665     }
666     case Instruction::SExt: {
667       GenericValue GV = getConstantValue(Op0);
668       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
669       GV.IntVal = GV.IntVal.sext(BitWidth);
670       return GV;
671     }
672     case Instruction::FPTrunc: {
673       // FIXME long double
674       GenericValue GV = getConstantValue(Op0);
675       GV.FloatVal = float(GV.DoubleVal);
676       return GV;
677     }
678     case Instruction::FPExt:{
679       // FIXME long double
680       GenericValue GV = getConstantValue(Op0);
681       GV.DoubleVal = double(GV.FloatVal);
682       return GV;
683     }
684     case Instruction::UIToFP: {
685       GenericValue GV = getConstantValue(Op0);
686       if (CE->getType()->isFloatTy())
687         GV.FloatVal = float(GV.IntVal.roundToDouble());
688       else if (CE->getType()->isDoubleTy())
689         GV.DoubleVal = GV.IntVal.roundToDouble();
690       else if (CE->getType()->isX86_FP80Ty()) {
691         APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended);
692         (void)apf.convertFromAPInt(GV.IntVal,
693                                    false,
694                                    APFloat::rmNearestTiesToEven);
695         GV.IntVal = apf.bitcastToAPInt();
696       }
697       return GV;
698     }
699     case Instruction::SIToFP: {
700       GenericValue GV = getConstantValue(Op0);
701       if (CE->getType()->isFloatTy())
702         GV.FloatVal = float(GV.IntVal.signedRoundToDouble());
703       else if (CE->getType()->isDoubleTy())
704         GV.DoubleVal = GV.IntVal.signedRoundToDouble();
705       else if (CE->getType()->isX86_FP80Ty()) {
706         APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended);
707         (void)apf.convertFromAPInt(GV.IntVal,
708                                    true,
709                                    APFloat::rmNearestTiesToEven);
710         GV.IntVal = apf.bitcastToAPInt();
711       }
712       return GV;
713     }
714     case Instruction::FPToUI: // double->APInt conversion handles sign
715     case Instruction::FPToSI: {
716       GenericValue GV = getConstantValue(Op0);
717       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
718       if (Op0->getType()->isFloatTy())
719         GV.IntVal = APIntOps::RoundFloatToAPInt(GV.FloatVal, BitWidth);
720       else if (Op0->getType()->isDoubleTy())
721         GV.IntVal = APIntOps::RoundDoubleToAPInt(GV.DoubleVal, BitWidth);
722       else if (Op0->getType()->isX86_FP80Ty()) {
723         APFloat apf = APFloat(APFloat::x87DoubleExtended, GV.IntVal);
724         uint64_t v;
725         bool ignored;
726         (void)apf.convertToInteger(&v, BitWidth,
727                                    CE->getOpcode()==Instruction::FPToSI,
728                                    APFloat::rmTowardZero, &ignored);
729         GV.IntVal = v; // endian?
730       }
731       return GV;
732     }
733     case Instruction::PtrToInt: {
734       GenericValue GV = getConstantValue(Op0);
735       uint32_t PtrWidth = DL.getTypeSizeInBits(Op0->getType());
736       assert(PtrWidth <= 64 && "Bad pointer width");
737       GV.IntVal = APInt(PtrWidth, uintptr_t(GV.PointerVal));
738       uint32_t IntWidth = DL.getTypeSizeInBits(CE->getType());
739       GV.IntVal = GV.IntVal.zextOrTrunc(IntWidth);
740       return GV;
741     }
742     case Instruction::IntToPtr: {
743       GenericValue GV = getConstantValue(Op0);
744       uint32_t PtrWidth = DL.getTypeSizeInBits(CE->getType());
745       GV.IntVal = GV.IntVal.zextOrTrunc(PtrWidth);
746       assert(GV.IntVal.getBitWidth() <= 64 && "Bad pointer width");
747       GV.PointerVal = PointerTy(uintptr_t(GV.IntVal.getZExtValue()));
748       return GV;
749     }
750     case Instruction::BitCast: {
751       GenericValue GV = getConstantValue(Op0);
752       Type* DestTy = CE->getType();
753       switch (Op0->getType()->getTypeID()) {
754         default: llvm_unreachable("Invalid bitcast operand");
755         case Type::IntegerTyID:
756           assert(DestTy->isFloatingPointTy() && "invalid bitcast");
757           if (DestTy->isFloatTy())
758             GV.FloatVal = GV.IntVal.bitsToFloat();
759           else if (DestTy->isDoubleTy())
760             GV.DoubleVal = GV.IntVal.bitsToDouble();
761           break;
762         case Type::FloatTyID:
763           assert(DestTy->isIntegerTy(32) && "Invalid bitcast");
764           GV.IntVal = APInt::floatToBits(GV.FloatVal);
765           break;
766         case Type::DoubleTyID:
767           assert(DestTy->isIntegerTy(64) && "Invalid bitcast");
768           GV.IntVal = APInt::doubleToBits(GV.DoubleVal);
769           break;
770         case Type::PointerTyID:
771           assert(DestTy->isPointerTy() && "Invalid bitcast");
772           break; // getConstantValue(Op0)  above already converted it
773       }
774       return GV;
775     }
776     case Instruction::Add:
777     case Instruction::FAdd:
778     case Instruction::Sub:
779     case Instruction::FSub:
780     case Instruction::Mul:
781     case Instruction::FMul:
782     case Instruction::UDiv:
783     case Instruction::SDiv:
784     case Instruction::URem:
785     case Instruction::SRem:
786     case Instruction::And:
787     case Instruction::Or:
788     case Instruction::Xor: {
789       GenericValue LHS = getConstantValue(Op0);
790       GenericValue RHS = getConstantValue(CE->getOperand(1));
791       GenericValue GV;
792       switch (CE->getOperand(0)->getType()->getTypeID()) {
793       default: llvm_unreachable("Bad add type!");
794       case Type::IntegerTyID:
795         switch (CE->getOpcode()) {
796           default: llvm_unreachable("Invalid integer opcode");
797           case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
798           case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
799           case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
800           case Instruction::UDiv:GV.IntVal = LHS.IntVal.udiv(RHS.IntVal); break;
801           case Instruction::SDiv:GV.IntVal = LHS.IntVal.sdiv(RHS.IntVal); break;
802           case Instruction::URem:GV.IntVal = LHS.IntVal.urem(RHS.IntVal); break;
803           case Instruction::SRem:GV.IntVal = LHS.IntVal.srem(RHS.IntVal); break;
804           case Instruction::And: GV.IntVal = LHS.IntVal & RHS.IntVal; break;
805           case Instruction::Or:  GV.IntVal = LHS.IntVal | RHS.IntVal; break;
806           case Instruction::Xor: GV.IntVal = LHS.IntVal ^ RHS.IntVal; break;
807         }
808         break;
809       case Type::FloatTyID:
810         switch (CE->getOpcode()) {
811           default: llvm_unreachable("Invalid float opcode");
812           case Instruction::FAdd:
813             GV.FloatVal = LHS.FloatVal + RHS.FloatVal; break;
814           case Instruction::FSub:
815             GV.FloatVal = LHS.FloatVal - RHS.FloatVal; break;
816           case Instruction::FMul:
817             GV.FloatVal = LHS.FloatVal * RHS.FloatVal; break;
818           case Instruction::FDiv:
819             GV.FloatVal = LHS.FloatVal / RHS.FloatVal; break;
820           case Instruction::FRem:
821             GV.FloatVal = std::fmod(LHS.FloatVal,RHS.FloatVal); break;
822         }
823         break;
824       case Type::DoubleTyID:
825         switch (CE->getOpcode()) {
826           default: llvm_unreachable("Invalid double opcode");
827           case Instruction::FAdd:
828             GV.DoubleVal = LHS.DoubleVal + RHS.DoubleVal; break;
829           case Instruction::FSub:
830             GV.DoubleVal = LHS.DoubleVal - RHS.DoubleVal; break;
831           case Instruction::FMul:
832             GV.DoubleVal = LHS.DoubleVal * RHS.DoubleVal; break;
833           case Instruction::FDiv:
834             GV.DoubleVal = LHS.DoubleVal / RHS.DoubleVal; break;
835           case Instruction::FRem:
836             GV.DoubleVal = std::fmod(LHS.DoubleVal,RHS.DoubleVal); break;
837         }
838         break;
839       case Type::X86_FP80TyID:
840       case Type::PPC_FP128TyID:
841       case Type::FP128TyID: {
842         const fltSemantics &Sem = CE->getOperand(0)->getType()->getFltSemantics();
843         APFloat apfLHS = APFloat(Sem, LHS.IntVal);
844         switch (CE->getOpcode()) {
845           default: llvm_unreachable("Invalid long double opcode");
846           case Instruction::FAdd:
847             apfLHS.add(APFloat(Sem, RHS.IntVal), APFloat::rmNearestTiesToEven);
848             GV.IntVal = apfLHS.bitcastToAPInt();
849             break;
850           case Instruction::FSub:
851             apfLHS.subtract(APFloat(Sem, RHS.IntVal),
852                             APFloat::rmNearestTiesToEven);
853             GV.IntVal = apfLHS.bitcastToAPInt();
854             break;
855           case Instruction::FMul:
856             apfLHS.multiply(APFloat(Sem, RHS.IntVal),
857                             APFloat::rmNearestTiesToEven);
858             GV.IntVal = apfLHS.bitcastToAPInt();
859             break;
860           case Instruction::FDiv:
861             apfLHS.divide(APFloat(Sem, RHS.IntVal),
862                           APFloat::rmNearestTiesToEven);
863             GV.IntVal = apfLHS.bitcastToAPInt();
864             break;
865           case Instruction::FRem:
866             apfLHS.mod(APFloat(Sem, RHS.IntVal));
867             GV.IntVal = apfLHS.bitcastToAPInt();
868             break;
869           }
870         }
871         break;
872       }
873       return GV;
874     }
875     default:
876       break;
877     }
878 
879     SmallString<256> Msg;
880     raw_svector_ostream OS(Msg);
881     OS << "ConstantExpr not handled: " << *CE;
882     report_fatal_error(OS.str());
883   }
884 
885   // Otherwise, we have a simple constant.
886   GenericValue Result;
887   switch (C->getType()->getTypeID()) {
888   case Type::FloatTyID:
889     Result.FloatVal = cast<ConstantFP>(C)->getValueAPF().convertToFloat();
890     break;
891   case Type::DoubleTyID:
892     Result.DoubleVal = cast<ConstantFP>(C)->getValueAPF().convertToDouble();
893     break;
894   case Type::X86_FP80TyID:
895   case Type::FP128TyID:
896   case Type::PPC_FP128TyID:
897     Result.IntVal = cast <ConstantFP>(C)->getValueAPF().bitcastToAPInt();
898     break;
899   case Type::IntegerTyID:
900     Result.IntVal = cast<ConstantInt>(C)->getValue();
901     break;
902   case Type::PointerTyID:
903     if (isa<ConstantPointerNull>(C))
904       Result.PointerVal = nullptr;
905     else if (const Function *F = dyn_cast<Function>(C))
906       Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
907     else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
908       Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
909     else
910       llvm_unreachable("Unknown constant pointer type!");
911     break;
912   case Type::VectorTyID: {
913     unsigned elemNum;
914     Type* ElemTy;
915     const ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(C);
916     const ConstantVector *CV = dyn_cast<ConstantVector>(C);
917     const ConstantAggregateZero *CAZ = dyn_cast<ConstantAggregateZero>(C);
918 
919     if (CDV) {
920         elemNum = CDV->getNumElements();
921         ElemTy = CDV->getElementType();
922     } else if (CV || CAZ) {
923         VectorType* VTy = dyn_cast<VectorType>(C->getType());
924         elemNum = VTy->getNumElements();
925         ElemTy = VTy->getElementType();
926     } else {
927         llvm_unreachable("Unknown constant vector type!");
928     }
929 
930     Result.AggregateVal.resize(elemNum);
931     // Check if vector holds floats.
932     if(ElemTy->isFloatTy()) {
933       if (CAZ) {
934         GenericValue floatZero;
935         floatZero.FloatVal = 0.f;
936         std::fill(Result.AggregateVal.begin(), Result.AggregateVal.end(),
937                   floatZero);
938         break;
939       }
940       if(CV) {
941         for (unsigned i = 0; i < elemNum; ++i)
942           if (!isa<UndefValue>(CV->getOperand(i)))
943             Result.AggregateVal[i].FloatVal = cast<ConstantFP>(
944               CV->getOperand(i))->getValueAPF().convertToFloat();
945         break;
946       }
947       if(CDV)
948         for (unsigned i = 0; i < elemNum; ++i)
949           Result.AggregateVal[i].FloatVal = CDV->getElementAsFloat(i);
950 
951       break;
952     }
953     // Check if vector holds doubles.
954     if (ElemTy->isDoubleTy()) {
955       if (CAZ) {
956         GenericValue doubleZero;
957         doubleZero.DoubleVal = 0.0;
958         std::fill(Result.AggregateVal.begin(), Result.AggregateVal.end(),
959                   doubleZero);
960         break;
961       }
962       if(CV) {
963         for (unsigned i = 0; i < elemNum; ++i)
964           if (!isa<UndefValue>(CV->getOperand(i)))
965             Result.AggregateVal[i].DoubleVal = cast<ConstantFP>(
966               CV->getOperand(i))->getValueAPF().convertToDouble();
967         break;
968       }
969       if(CDV)
970         for (unsigned i = 0; i < elemNum; ++i)
971           Result.AggregateVal[i].DoubleVal = CDV->getElementAsDouble(i);
972 
973       break;
974     }
975     // Check if vector holds integers.
976     if (ElemTy->isIntegerTy()) {
977       if (CAZ) {
978         GenericValue intZero;
979         intZero.IntVal = APInt(ElemTy->getScalarSizeInBits(), 0ull);
980         std::fill(Result.AggregateVal.begin(), Result.AggregateVal.end(),
981                   intZero);
982         break;
983       }
984       if(CV) {
985         for (unsigned i = 0; i < elemNum; ++i)
986           if (!isa<UndefValue>(CV->getOperand(i)))
987             Result.AggregateVal[i].IntVal = cast<ConstantInt>(
988                                             CV->getOperand(i))->getValue();
989           else {
990             Result.AggregateVal[i].IntVal =
991               APInt(CV->getOperand(i)->getType()->getPrimitiveSizeInBits(), 0);
992           }
993         break;
994       }
995       if(CDV)
996         for (unsigned i = 0; i < elemNum; ++i)
997           Result.AggregateVal[i].IntVal = APInt(
998             CDV->getElementType()->getPrimitiveSizeInBits(),
999             CDV->getElementAsInteger(i));
1000 
1001       break;
1002     }
1003     llvm_unreachable("Unknown constant pointer type!");
1004   }
1005   break;
1006 
1007   default:
1008     SmallString<256> Msg;
1009     raw_svector_ostream OS(Msg);
1010     OS << "ERROR: Constant unimplemented for type: " << *C->getType();
1011     report_fatal_error(OS.str());
1012   }
1013 
1014   return Result;
1015 }
1016 
1017 /// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
1018 /// with the integer held in IntVal.
StoreIntToMemory(const APInt & IntVal,uint8_t * Dst,unsigned StoreBytes)1019 static void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
1020                              unsigned StoreBytes) {
1021   assert((IntVal.getBitWidth()+7)/8 >= StoreBytes && "Integer too small!");
1022   const uint8_t *Src = (const uint8_t *)IntVal.getRawData();
1023 
1024   if (sys::IsLittleEndianHost) {
1025     // Little-endian host - the source is ordered from LSB to MSB.  Order the
1026     // destination from LSB to MSB: Do a straight copy.
1027     memcpy(Dst, Src, StoreBytes);
1028   } else {
1029     // Big-endian host - the source is an array of 64 bit words ordered from
1030     // LSW to MSW.  Each word is ordered from MSB to LSB.  Order the destination
1031     // from MSB to LSB: Reverse the word order, but not the bytes in a word.
1032     while (StoreBytes > sizeof(uint64_t)) {
1033       StoreBytes -= sizeof(uint64_t);
1034       // May not be aligned so use memcpy.
1035       memcpy(Dst + StoreBytes, Src, sizeof(uint64_t));
1036       Src += sizeof(uint64_t);
1037     }
1038 
1039     memcpy(Dst, Src + sizeof(uint64_t) - StoreBytes, StoreBytes);
1040   }
1041 }
1042 
StoreValueToMemory(const GenericValue & Val,GenericValue * Ptr,Type * Ty)1043 void ExecutionEngine::StoreValueToMemory(const GenericValue &Val,
1044                                          GenericValue *Ptr, Type *Ty) {
1045   const unsigned StoreBytes = getDataLayout().getTypeStoreSize(Ty);
1046 
1047   switch (Ty->getTypeID()) {
1048   default:
1049     dbgs() << "Cannot store value of type " << *Ty << "!\n";
1050     break;
1051   case Type::IntegerTyID:
1052     StoreIntToMemory(Val.IntVal, (uint8_t*)Ptr, StoreBytes);
1053     break;
1054   case Type::FloatTyID:
1055     *((float*)Ptr) = Val.FloatVal;
1056     break;
1057   case Type::DoubleTyID:
1058     *((double*)Ptr) = Val.DoubleVal;
1059     break;
1060   case Type::X86_FP80TyID:
1061     memcpy(Ptr, Val.IntVal.getRawData(), 10);
1062     break;
1063   case Type::PointerTyID:
1064     // Ensure 64 bit target pointers are fully initialized on 32 bit hosts.
1065     if (StoreBytes != sizeof(PointerTy))
1066       memset(&(Ptr->PointerVal), 0, StoreBytes);
1067 
1068     *((PointerTy*)Ptr) = Val.PointerVal;
1069     break;
1070   case Type::VectorTyID:
1071     for (unsigned i = 0; i < Val.AggregateVal.size(); ++i) {
1072       if (cast<VectorType>(Ty)->getElementType()->isDoubleTy())
1073         *(((double*)Ptr)+i) = Val.AggregateVal[i].DoubleVal;
1074       if (cast<VectorType>(Ty)->getElementType()->isFloatTy())
1075         *(((float*)Ptr)+i) = Val.AggregateVal[i].FloatVal;
1076       if (cast<VectorType>(Ty)->getElementType()->isIntegerTy()) {
1077         unsigned numOfBytes =(Val.AggregateVal[i].IntVal.getBitWidth()+7)/8;
1078         StoreIntToMemory(Val.AggregateVal[i].IntVal,
1079           (uint8_t*)Ptr + numOfBytes*i, numOfBytes);
1080       }
1081     }
1082     break;
1083   }
1084 
1085   if (sys::IsLittleEndianHost != getDataLayout().isLittleEndian())
1086     // Host and target are different endian - reverse the stored bytes.
1087     std::reverse((uint8_t*)Ptr, StoreBytes + (uint8_t*)Ptr);
1088 }
1089 
1090 /// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
1091 /// from Src into IntVal, which is assumed to be wide enough and to hold zero.
LoadIntFromMemory(APInt & IntVal,uint8_t * Src,unsigned LoadBytes)1092 static void LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes) {
1093   assert((IntVal.getBitWidth()+7)/8 >= LoadBytes && "Integer too small!");
1094   uint8_t *Dst = reinterpret_cast<uint8_t *>(
1095                    const_cast<uint64_t *>(IntVal.getRawData()));
1096 
1097   if (sys::IsLittleEndianHost)
1098     // Little-endian host - the destination must be ordered from LSB to MSB.
1099     // The source is ordered from LSB to MSB: Do a straight copy.
1100     memcpy(Dst, Src, LoadBytes);
1101   else {
1102     // Big-endian - the destination is an array of 64 bit words ordered from
1103     // LSW to MSW.  Each word must be ordered from MSB to LSB.  The source is
1104     // ordered from MSB to LSB: Reverse the word order, but not the bytes in
1105     // a word.
1106     while (LoadBytes > sizeof(uint64_t)) {
1107       LoadBytes -= sizeof(uint64_t);
1108       // May not be aligned so use memcpy.
1109       memcpy(Dst, Src + LoadBytes, sizeof(uint64_t));
1110       Dst += sizeof(uint64_t);
1111     }
1112 
1113     memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
1114   }
1115 }
1116 
1117 /// FIXME: document
1118 ///
LoadValueFromMemory(GenericValue & Result,GenericValue * Ptr,Type * Ty)1119 void ExecutionEngine::LoadValueFromMemory(GenericValue &Result,
1120                                           GenericValue *Ptr,
1121                                           Type *Ty) {
1122   const unsigned LoadBytes = getDataLayout().getTypeStoreSize(Ty);
1123 
1124   switch (Ty->getTypeID()) {
1125   case Type::IntegerTyID:
1126     // An APInt with all words initially zero.
1127     Result.IntVal = APInt(cast<IntegerType>(Ty)->getBitWidth(), 0);
1128     LoadIntFromMemory(Result.IntVal, (uint8_t*)Ptr, LoadBytes);
1129     break;
1130   case Type::FloatTyID:
1131     Result.FloatVal = *((float*)Ptr);
1132     break;
1133   case Type::DoubleTyID:
1134     Result.DoubleVal = *((double*)Ptr);
1135     break;
1136   case Type::PointerTyID:
1137     Result.PointerVal = *((PointerTy*)Ptr);
1138     break;
1139   case Type::X86_FP80TyID: {
1140     // This is endian dependent, but it will only work on x86 anyway.
1141     // FIXME: Will not trap if loading a signaling NaN.
1142     uint64_t y[2];
1143     memcpy(y, Ptr, 10);
1144     Result.IntVal = APInt(80, y);
1145     break;
1146   }
1147   case Type::VectorTyID: {
1148     auto *VT = cast<VectorType>(Ty);
1149     Type *ElemT = VT->getElementType();
1150     const unsigned numElems = VT->getNumElements();
1151     if (ElemT->isFloatTy()) {
1152       Result.AggregateVal.resize(numElems);
1153       for (unsigned i = 0; i < numElems; ++i)
1154         Result.AggregateVal[i].FloatVal = *((float*)Ptr+i);
1155     }
1156     if (ElemT->isDoubleTy()) {
1157       Result.AggregateVal.resize(numElems);
1158       for (unsigned i = 0; i < numElems; ++i)
1159         Result.AggregateVal[i].DoubleVal = *((double*)Ptr+i);
1160     }
1161     if (ElemT->isIntegerTy()) {
1162       GenericValue intZero;
1163       const unsigned elemBitWidth = cast<IntegerType>(ElemT)->getBitWidth();
1164       intZero.IntVal = APInt(elemBitWidth, 0);
1165       Result.AggregateVal.resize(numElems, intZero);
1166       for (unsigned i = 0; i < numElems; ++i)
1167         LoadIntFromMemory(Result.AggregateVal[i].IntVal,
1168           (uint8_t*)Ptr+((elemBitWidth+7)/8)*i, (elemBitWidth+7)/8);
1169     }
1170   break;
1171   }
1172   default:
1173     SmallString<256> Msg;
1174     raw_svector_ostream OS(Msg);
1175     OS << "Cannot load value of type " << *Ty << "!";
1176     report_fatal_error(OS.str());
1177   }
1178 }
1179 
InitializeMemory(const Constant * Init,void * Addr)1180 void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
1181   DEBUG(dbgs() << "JIT: Initializing " << Addr << " ");
1182   DEBUG(Init->dump());
1183   if (isa<UndefValue>(Init))
1184     return;
1185 
1186   if (const ConstantVector *CP = dyn_cast<ConstantVector>(Init)) {
1187     unsigned ElementSize =
1188         getDataLayout().getTypeAllocSize(CP->getType()->getElementType());
1189     for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
1190       InitializeMemory(CP->getOperand(i), (char*)Addr+i*ElementSize);
1191     return;
1192   }
1193 
1194   if (isa<ConstantAggregateZero>(Init)) {
1195     memset(Addr, 0, (size_t)getDataLayout().getTypeAllocSize(Init->getType()));
1196     return;
1197   }
1198 
1199   if (const ConstantArray *CPA = dyn_cast<ConstantArray>(Init)) {
1200     unsigned ElementSize =
1201         getDataLayout().getTypeAllocSize(CPA->getType()->getElementType());
1202     for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
1203       InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
1204     return;
1205   }
1206 
1207   if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(Init)) {
1208     const StructLayout *SL =
1209         getDataLayout().getStructLayout(cast<StructType>(CPS->getType()));
1210     for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
1211       InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->getElementOffset(i));
1212     return;
1213   }
1214 
1215   if (const ConstantDataSequential *CDS =
1216                dyn_cast<ConstantDataSequential>(Init)) {
1217     // CDS is already laid out in host memory order.
1218     StringRef Data = CDS->getRawDataValues();
1219     memcpy(Addr, Data.data(), Data.size());
1220     return;
1221   }
1222 
1223   if (Init->getType()->isFirstClassType()) {
1224     GenericValue Val = getConstantValue(Init);
1225     StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
1226     return;
1227   }
1228 
1229   DEBUG(dbgs() << "Bad Type: " << *Init->getType() << "\n");
1230   llvm_unreachable("Unknown constant type to initialize memory with!");
1231 }
1232 
1233 /// EmitGlobals - Emit all of the global variables to memory, storing their
1234 /// addresses into GlobalAddress.  This must make sure to copy the contents of
1235 /// their initializers into the memory.
emitGlobals()1236 void ExecutionEngine::emitGlobals() {
1237   // Loop over all of the global variables in the program, allocating the memory
1238   // to hold them.  If there is more than one module, do a prepass over globals
1239   // to figure out how the different modules should link together.
1240   std::map<std::pair<std::string, Type*>,
1241            const GlobalValue*> LinkedGlobalsMap;
1242 
1243   if (Modules.size() != 1) {
1244     for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
1245       Module &M = *Modules[m];
1246       for (const auto &GV : M.globals()) {
1247         if (GV.hasLocalLinkage() || GV.isDeclaration() ||
1248             GV.hasAppendingLinkage() || !GV.hasName())
1249           continue;// Ignore external globals and globals with internal linkage.
1250 
1251         const GlobalValue *&GVEntry =
1252           LinkedGlobalsMap[std::make_pair(GV.getName(), GV.getType())];
1253 
1254         // If this is the first time we've seen this global, it is the canonical
1255         // version.
1256         if (!GVEntry) {
1257           GVEntry = &GV;
1258           continue;
1259         }
1260 
1261         // If the existing global is strong, never replace it.
1262         if (GVEntry->hasExternalLinkage())
1263           continue;
1264 
1265         // Otherwise, we know it's linkonce/weak, replace it if this is a strong
1266         // symbol.  FIXME is this right for common?
1267         if (GV.hasExternalLinkage() || GVEntry->hasExternalWeakLinkage())
1268           GVEntry = &GV;
1269       }
1270     }
1271   }
1272 
1273   std::vector<const GlobalValue*> NonCanonicalGlobals;
1274   for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
1275     Module &M = *Modules[m];
1276     for (const auto &GV : M.globals()) {
1277       // In the multi-module case, see what this global maps to.
1278       if (!LinkedGlobalsMap.empty()) {
1279         if (const GlobalValue *GVEntry =
1280               LinkedGlobalsMap[std::make_pair(GV.getName(), GV.getType())]) {
1281           // If something else is the canonical global, ignore this one.
1282           if (GVEntry != &GV) {
1283             NonCanonicalGlobals.push_back(&GV);
1284             continue;
1285           }
1286         }
1287       }
1288 
1289       if (!GV.isDeclaration()) {
1290         addGlobalMapping(&GV, getMemoryForGV(&GV));
1291       } else {
1292         // External variable reference. Try to use the dynamic loader to
1293         // get a pointer to it.
1294         if (void *SymAddr =
1295             sys::DynamicLibrary::SearchForAddressOfSymbol(GV.getName()))
1296           addGlobalMapping(&GV, SymAddr);
1297         else {
1298           report_fatal_error("Could not resolve external global address: "
1299                             +GV.getName());
1300         }
1301       }
1302     }
1303 
1304     // If there are multiple modules, map the non-canonical globals to their
1305     // canonical location.
1306     if (!NonCanonicalGlobals.empty()) {
1307       for (unsigned i = 0, e = NonCanonicalGlobals.size(); i != e; ++i) {
1308         const GlobalValue *GV = NonCanonicalGlobals[i];
1309         const GlobalValue *CGV =
1310           LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
1311         void *Ptr = getPointerToGlobalIfAvailable(CGV);
1312         assert(Ptr && "Canonical global wasn't codegen'd!");
1313         addGlobalMapping(GV, Ptr);
1314       }
1315     }
1316 
1317     // Now that all of the globals are set up in memory, loop through them all
1318     // and initialize their contents.
1319     for (const auto &GV : M.globals()) {
1320       if (!GV.isDeclaration()) {
1321         if (!LinkedGlobalsMap.empty()) {
1322           if (const GlobalValue *GVEntry =
1323                 LinkedGlobalsMap[std::make_pair(GV.getName(), GV.getType())])
1324             if (GVEntry != &GV)  // Not the canonical variable.
1325               continue;
1326         }
1327         EmitGlobalVariable(&GV);
1328       }
1329     }
1330   }
1331 }
1332 
1333 // EmitGlobalVariable - This method emits the specified global variable to the
1334 // address specified in GlobalAddresses, or allocates new memory if it's not
1335 // already in the map.
EmitGlobalVariable(const GlobalVariable * GV)1336 void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
1337   void *GA = getPointerToGlobalIfAvailable(GV);
1338 
1339   if (!GA) {
1340     // If it's not already specified, allocate memory for the global.
1341     GA = getMemoryForGV(GV);
1342 
1343     // If we failed to allocate memory for this global, return.
1344     if (!GA) return;
1345 
1346     addGlobalMapping(GV, GA);
1347   }
1348 
1349   // Don't initialize if it's thread local, let the client do it.
1350   if (!GV->isThreadLocal())
1351     InitializeMemory(GV->getInitializer(), GA);
1352 
1353   Type *ElTy = GV->getValueType();
1354   size_t GVSize = (size_t)getDataLayout().getTypeAllocSize(ElTy);
1355   NumInitBytes += (unsigned)GVSize;
1356   ++NumGlobals;
1357 }
1358