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