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