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      1 //===-- ExecutionEngine.cpp - Common Implementation shared by EEs ---------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines the common interface used by the various execution engine
     11 // subclasses.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #define DEBUG_TYPE "jit"
     16 #include "llvm/ExecutionEngine/ExecutionEngine.h"
     17 
     18 #include "llvm/Constants.h"
     19 #include "llvm/DerivedTypes.h"
     20 #include "llvm/Module.h"
     21 #include "llvm/ExecutionEngine/GenericValue.h"
     22 #include "llvm/ADT/SmallString.h"
     23 #include "llvm/ADT/Statistic.h"
     24 #include "llvm/Support/Debug.h"
     25 #include "llvm/Support/ErrorHandling.h"
     26 #include "llvm/Support/MutexGuard.h"
     27 #include "llvm/Support/ValueHandle.h"
     28 #include "llvm/Support/raw_ostream.h"
     29 #include "llvm/Support/DynamicLibrary.h"
     30 #include "llvm/Support/Host.h"
     31 #include "llvm/Target/TargetData.h"
     32 #include "llvm/Target/TargetMachine.h"
     33 #include <cmath>
     34 #include <cstring>
     35 using namespace llvm;
     36 
     37 STATISTIC(NumInitBytes, "Number of bytes of global vars initialized");
     38 STATISTIC(NumGlobals  , "Number of global vars initialized");
     39 
     40 ExecutionEngine *(*ExecutionEngine::JITCtor)(
     41   Module *M,
     42   std::string *ErrorStr,
     43   JITMemoryManager *JMM,
     44   CodeGenOpt::Level OptLevel,
     45   bool GVsWithCode,
     46   TargetMachine *TM) = 0;
     47 ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
     48   Module *M,
     49   std::string *ErrorStr,
     50   JITMemoryManager *JMM,
     51   CodeGenOpt::Level OptLevel,
     52   bool GVsWithCode,
     53   TargetMachine *TM) = 0;
     54 ExecutionEngine *(*ExecutionEngine::InterpCtor)(Module *M,
     55                                                 std::string *ErrorStr) = 0;
     56 
     57 ExecutionEngine::ExecutionEngine(Module *M)
     58   : EEState(*this),
     59     LazyFunctionCreator(0),
     60     ExceptionTableRegister(0),
     61     ExceptionTableDeregister(0) {
     62   CompilingLazily         = false;
     63   GVCompilationDisabled   = false;
     64   SymbolSearchingDisabled = false;
     65   Modules.push_back(M);
     66   assert(M && "Module is null?");
     67 }
     68 
     69 ExecutionEngine::~ExecutionEngine() {
     70   clearAllGlobalMappings();
     71   for (unsigned i = 0, e = Modules.size(); i != e; ++i)
     72     delete Modules[i];
     73 }
     74 
     75 void ExecutionEngine::DeregisterAllTables() {
     76   if (ExceptionTableDeregister) {
     77     DenseMap<const Function*, void*>::iterator it = AllExceptionTables.begin();
     78     DenseMap<const Function*, void*>::iterator ite = AllExceptionTables.end();
     79     for (; it != ite; ++it)
     80       ExceptionTableDeregister(it->second);
     81     AllExceptionTables.clear();
     82   }
     83 }
     84 
     85 namespace {
     86 /// \brief Helper class which uses a value handler to automatically deletes the
     87 /// memory block when the GlobalVariable is destroyed.
     88 class GVMemoryBlock : public CallbackVH {
     89   GVMemoryBlock(const GlobalVariable *GV)
     90     : CallbackVH(const_cast<GlobalVariable*>(GV)) {}
     91 
     92 public:
     93   /// \brief Returns the address the GlobalVariable should be written into.  The
     94   /// GVMemoryBlock object prefixes that.
     95   static char *Create(const GlobalVariable *GV, const TargetData& TD) {
     96     Type *ElTy = GV->getType()->getElementType();
     97     size_t GVSize = (size_t)TD.getTypeAllocSize(ElTy);
     98     void *RawMemory = ::operator new(
     99       TargetData::RoundUpAlignment(sizeof(GVMemoryBlock),
    100                                    TD.getPreferredAlignment(GV))
    101       + GVSize);
    102     new(RawMemory) GVMemoryBlock(GV);
    103     return static_cast<char*>(RawMemory) + sizeof(GVMemoryBlock);
    104   }
    105 
    106   virtual void deleted() {
    107     // We allocated with operator new and with some extra memory hanging off the
    108     // end, so don't just delete this.  I'm not sure if this is actually
    109     // required.
    110     this->~GVMemoryBlock();
    111     ::operator delete(this);
    112   }
    113 };
    114 }  // anonymous namespace
    115 
    116 char *ExecutionEngine::getMemoryForGV(const GlobalVariable *GV) {
    117   return GVMemoryBlock::Create(GV, *getTargetData());
    118 }
    119 
    120 bool ExecutionEngine::removeModule(Module *M) {
    121   for(SmallVector<Module *, 1>::iterator I = Modules.begin(),
    122         E = Modules.end(); I != E; ++I) {
    123     Module *Found = *I;
    124     if (Found == M) {
    125       Modules.erase(I);
    126       clearGlobalMappingsFromModule(M);
    127       return true;
    128     }
    129   }
    130   return false;
    131 }
    132 
    133 Function *ExecutionEngine::FindFunctionNamed(const char *FnName) {
    134   for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
    135     if (Function *F = Modules[i]->getFunction(FnName))
    136       return F;
    137   }
    138   return 0;
    139 }
    140 
    141 
    142 void *ExecutionEngineState::RemoveMapping(const MutexGuard &,
    143                                           const GlobalValue *ToUnmap) {
    144   GlobalAddressMapTy::iterator I = GlobalAddressMap.find(ToUnmap);
    145   void *OldVal;
    146 
    147   // FIXME: This is silly, we shouldn't end up with a mapping -> 0 in the
    148   // GlobalAddressMap.
    149   if (I == GlobalAddressMap.end())
    150     OldVal = 0;
    151   else {
    152     OldVal = I->second;
    153     GlobalAddressMap.erase(I);
    154   }
    155 
    156   GlobalAddressReverseMap.erase(OldVal);
    157   return OldVal;
    158 }
    159 
    160 void ExecutionEngine::addGlobalMapping(const GlobalValue *GV, void *Addr) {
    161   MutexGuard locked(lock);
    162 
    163   DEBUG(dbgs() << "JIT: Map \'" << GV->getName()
    164         << "\' to [" << Addr << "]\n";);
    165   void *&CurVal = EEState.getGlobalAddressMap(locked)[GV];
    166   assert((CurVal == 0 || Addr == 0) && "GlobalMapping already established!");
    167   CurVal = Addr;
    168 
    169   // If we are using the reverse mapping, add it too.
    170   if (!EEState.getGlobalAddressReverseMap(locked).empty()) {
    171     AssertingVH<const GlobalValue> &V =
    172       EEState.getGlobalAddressReverseMap(locked)[Addr];
    173     assert((V == 0 || GV == 0) && "GlobalMapping already established!");
    174     V = GV;
    175   }
    176 }
    177 
    178 void ExecutionEngine::clearAllGlobalMappings() {
    179   MutexGuard locked(lock);
    180 
    181   EEState.getGlobalAddressMap(locked).clear();
    182   EEState.getGlobalAddressReverseMap(locked).clear();
    183 }
    184 
    185 void ExecutionEngine::clearGlobalMappingsFromModule(Module *M) {
    186   MutexGuard locked(lock);
    187 
    188   for (Module::iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI)
    189     EEState.RemoveMapping(locked, FI);
    190   for (Module::global_iterator GI = M->global_begin(), GE = M->global_end();
    191        GI != GE; ++GI)
    192     EEState.RemoveMapping(locked, GI);
    193 }
    194 
    195 void *ExecutionEngine::updateGlobalMapping(const GlobalValue *GV, void *Addr) {
    196   MutexGuard locked(lock);
    197 
    198   ExecutionEngineState::GlobalAddressMapTy &Map =
    199     EEState.getGlobalAddressMap(locked);
    200 
    201   // Deleting from the mapping?
    202   if (Addr == 0)
    203     return EEState.RemoveMapping(locked, GV);
    204 
    205   void *&CurVal = Map[GV];
    206   void *OldVal = CurVal;
    207 
    208   if (CurVal && !EEState.getGlobalAddressReverseMap(locked).empty())
    209     EEState.getGlobalAddressReverseMap(locked).erase(CurVal);
    210   CurVal = Addr;
    211 
    212   // If we are using the reverse mapping, add it too.
    213   if (!EEState.getGlobalAddressReverseMap(locked).empty()) {
    214     AssertingVH<const GlobalValue> &V =
    215       EEState.getGlobalAddressReverseMap(locked)[Addr];
    216     assert((V == 0 || GV == 0) && "GlobalMapping already established!");
    217     V = GV;
    218   }
    219   return OldVal;
    220 }
    221 
    222 void *ExecutionEngine::getPointerToGlobalIfAvailable(const GlobalValue *GV) {
    223   MutexGuard locked(lock);
    224 
    225   ExecutionEngineState::GlobalAddressMapTy::iterator I =
    226     EEState.getGlobalAddressMap(locked).find(GV);
    227   return I != EEState.getGlobalAddressMap(locked).end() ? I->second : 0;
    228 }
    229 
    230 const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
    231   MutexGuard locked(lock);
    232 
    233   // If we haven't computed the reverse mapping yet, do so first.
    234   if (EEState.getGlobalAddressReverseMap(locked).empty()) {
    235     for (ExecutionEngineState::GlobalAddressMapTy::iterator
    236          I = EEState.getGlobalAddressMap(locked).begin(),
    237          E = EEState.getGlobalAddressMap(locked).end(); I != E; ++I)
    238       EEState.getGlobalAddressReverseMap(locked).insert(std::make_pair(
    239                                                           I->second, I->first));
    240   }
    241 
    242   std::map<void *, AssertingVH<const GlobalValue> >::iterator I =
    243     EEState.getGlobalAddressReverseMap(locked).find(Addr);
    244   return I != EEState.getGlobalAddressReverseMap(locked).end() ? I->second : 0;
    245 }
    246 
    247 namespace {
    248 class ArgvArray {
    249   char *Array;
    250   std::vector<char*> Values;
    251 public:
    252   ArgvArray() : Array(NULL) {}
    253   ~ArgvArray() { clear(); }
    254   void clear() {
    255     delete[] Array;
    256     Array = NULL;
    257     for (size_t I = 0, E = Values.size(); I != E; ++I) {
    258       delete[] Values[I];
    259     }
    260     Values.clear();
    261   }
    262   /// Turn a vector of strings into a nice argv style array of pointers to null
    263   /// terminated strings.
    264   void *reset(LLVMContext &C, ExecutionEngine *EE,
    265               const std::vector<std::string> &InputArgv);
    266 };
    267 }  // anonymous namespace
    268 void *ArgvArray::reset(LLVMContext &C, ExecutionEngine *EE,
    269                        const std::vector<std::string> &InputArgv) {
    270   clear();  // Free the old contents.
    271   unsigned PtrSize = EE->getTargetData()->getPointerSize();
    272   Array = new char[(InputArgv.size()+1)*PtrSize];
    273 
    274   DEBUG(dbgs() << "JIT: ARGV = " << (void*)Array << "\n");
    275   Type *SBytePtr = Type::getInt8PtrTy(C);
    276 
    277   for (unsigned i = 0; i != InputArgv.size(); ++i) {
    278     unsigned Size = InputArgv[i].size()+1;
    279     char *Dest = new char[Size];
    280     Values.push_back(Dest);
    281     DEBUG(dbgs() << "JIT: ARGV[" << i << "] = " << (void*)Dest << "\n");
    282 
    283     std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest);
    284     Dest[Size-1] = 0;
    285 
    286     // Endian safe: Array[i] = (PointerTy)Dest;
    287     EE->StoreValueToMemory(PTOGV(Dest), (GenericValue*)(Array+i*PtrSize),
    288                            SBytePtr);
    289   }
    290 
    291   // Null terminate it
    292   EE->StoreValueToMemory(PTOGV(0),
    293                          (GenericValue*)(Array+InputArgv.size()*PtrSize),
    294                          SBytePtr);
    295   return Array;
    296 }
    297 
    298 void ExecutionEngine::runStaticConstructorsDestructors(Module *module,
    299                                                        bool isDtors) {
    300   const char *Name = isDtors ? "llvm.global_dtors" : "llvm.global_ctors";
    301   GlobalVariable *GV = module->getNamedGlobal(Name);
    302 
    303   // If this global has internal linkage, or if it has a use, then it must be
    304   // an old-style (llvmgcc3) static ctor with __main linked in and in use.  If
    305   // this is the case, don't execute any of the global ctors, __main will do
    306   // it.
    307   if (!GV || GV->isDeclaration() || GV->hasLocalLinkage()) return;
    308 
    309   // Should be an array of '{ i32, void ()* }' structs.  The first value is
    310   // the init priority, which we ignore.
    311   if (isa<ConstantAggregateZero>(GV->getInitializer()))
    312     return;
    313   ConstantArray *InitList = cast<ConstantArray>(GV->getInitializer());
    314   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
    315     if (isa<ConstantAggregateZero>(InitList->getOperand(i)))
    316       continue;
    317     ConstantStruct *CS = cast<ConstantStruct>(InitList->getOperand(i));
    318 
    319     Constant *FP = CS->getOperand(1);
    320     if (FP->isNullValue())
    321       continue;  // Found a sentinal value, ignore.
    322 
    323     // Strip off constant expression casts.
    324     if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
    325       if (CE->isCast())
    326         FP = CE->getOperand(0);
    327 
    328     // Execute the ctor/dtor function!
    329     if (Function *F = dyn_cast<Function>(FP))
    330       runFunction(F, std::vector<GenericValue>());
    331 
    332     // FIXME: It is marginally lame that we just do nothing here if we see an
    333     // entry we don't recognize. It might not be unreasonable for the verifier
    334     // to not even allow this and just assert here.
    335   }
    336 }
    337 
    338 void ExecutionEngine::runStaticConstructorsDestructors(bool isDtors) {
    339   // Execute global ctors/dtors for each module in the program.
    340   for (unsigned i = 0, e = Modules.size(); i != e; ++i)
    341     runStaticConstructorsDestructors(Modules[i], isDtors);
    342 }
    343 
    344 #ifndef NDEBUG
    345 /// isTargetNullPtr - Return whether the target pointer stored at Loc is null.
    346 static bool isTargetNullPtr(ExecutionEngine *EE, void *Loc) {
    347   unsigned PtrSize = EE->getTargetData()->getPointerSize();
    348   for (unsigned i = 0; i < PtrSize; ++i)
    349     if (*(i + (uint8_t*)Loc))
    350       return false;
    351   return true;
    352 }
    353 #endif
    354 
    355 int ExecutionEngine::runFunctionAsMain(Function *Fn,
    356                                        const std::vector<std::string> &argv,
    357                                        const char * const * envp) {
    358   std::vector<GenericValue> GVArgs;
    359   GenericValue GVArgc;
    360   GVArgc.IntVal = APInt(32, argv.size());
    361 
    362   // Check main() type
    363   unsigned NumArgs = Fn->getFunctionType()->getNumParams();
    364   FunctionType *FTy = Fn->getFunctionType();
    365   Type* PPInt8Ty = Type::getInt8PtrTy(Fn->getContext())->getPointerTo();
    366 
    367   // Check the argument types.
    368   if (NumArgs > 3)
    369     report_fatal_error("Invalid number of arguments of main() supplied");
    370   if (NumArgs >= 3 && FTy->getParamType(2) != PPInt8Ty)
    371     report_fatal_error("Invalid type for third argument of main() supplied");
    372   if (NumArgs >= 2 && FTy->getParamType(1) != PPInt8Ty)
    373     report_fatal_error("Invalid type for second argument of main() supplied");
    374   if (NumArgs >= 1 && !FTy->getParamType(0)->isIntegerTy(32))
    375     report_fatal_error("Invalid type for first argument of main() supplied");
    376   if (!FTy->getReturnType()->isIntegerTy() &&
    377       !FTy->getReturnType()->isVoidTy())
    378     report_fatal_error("Invalid return type of main() supplied");
    379 
    380   ArgvArray CArgv;
    381   ArgvArray CEnv;
    382   if (NumArgs) {
    383     GVArgs.push_back(GVArgc); // Arg #0 = argc.
    384     if (NumArgs > 1) {
    385       // Arg #1 = argv.
    386       GVArgs.push_back(PTOGV(CArgv.reset(Fn->getContext(), this, argv)));
    387       assert(!isTargetNullPtr(this, GVTOP(GVArgs[1])) &&
    388              "argv[0] was null after CreateArgv");
    389       if (NumArgs > 2) {
    390         std::vector<std::string> EnvVars;
    391         for (unsigned i = 0; envp[i]; ++i)
    392           EnvVars.push_back(envp[i]);
    393         // Arg #2 = envp.
    394         GVArgs.push_back(PTOGV(CEnv.reset(Fn->getContext(), this, EnvVars)));
    395       }
    396     }
    397   }
    398 
    399   return runFunction(Fn, GVArgs).IntVal.getZExtValue();
    400 }
    401 
    402 ExecutionEngine *ExecutionEngine::create(Module *M,
    403                                          bool ForceInterpreter,
    404                                          std::string *ErrorStr,
    405                                          CodeGenOpt::Level OptLevel,
    406                                          bool GVsWithCode) {
    407   return EngineBuilder(M)
    408       .setEngineKind(ForceInterpreter
    409                      ? EngineKind::Interpreter
    410                      : EngineKind::JIT)
    411       .setErrorStr(ErrorStr)
    412       .setOptLevel(OptLevel)
    413       .setAllocateGVsWithCode(GVsWithCode)
    414       .create();
    415 }
    416 
    417 /// createJIT - This is the factory method for creating a JIT for the current
    418 /// machine, it does not fall back to the interpreter.  This takes ownership
    419 /// of the module.
    420 ExecutionEngine *ExecutionEngine::createJIT(Module *M,
    421                                             std::string *ErrorStr,
    422                                             JITMemoryManager *JMM,
    423                                             CodeGenOpt::Level OptLevel,
    424                                             bool GVsWithCode,
    425                                             Reloc::Model RM,
    426                                             CodeModel::Model CMM) {
    427   if (ExecutionEngine::JITCtor == 0) {
    428     if (ErrorStr)
    429       *ErrorStr = "JIT has not been linked in.";
    430     return 0;
    431   }
    432 
    433   // Use the defaults for extra parameters.  Users can use EngineBuilder to
    434   // set them.
    435   StringRef MArch = "";
    436   StringRef MCPU = "";
    437   SmallVector<std::string, 1> MAttrs;
    438 
    439   TargetMachine *TM =
    440     EngineBuilder::selectTarget(M, MArch, MCPU, MAttrs, RM, ErrorStr);
    441   if (!TM || (ErrorStr && ErrorStr->length() > 0)) return 0;
    442   TM->setCodeModel(CMM);
    443 
    444   return ExecutionEngine::JITCtor(M, ErrorStr, JMM, OptLevel, GVsWithCode, TM);
    445 }
    446 
    447 ExecutionEngine *EngineBuilder::create() {
    448   // Make sure we can resolve symbols in the program as well. The zero arg
    449   // to the function tells DynamicLibrary to load the program, not a library.
    450   if (sys::DynamicLibrary::LoadLibraryPermanently(0, ErrorStr))
    451     return 0;
    452 
    453   // If the user specified a memory manager but didn't specify which engine to
    454   // create, we assume they only want the JIT, and we fail if they only want
    455   // the interpreter.
    456   if (JMM) {
    457     if (WhichEngine & EngineKind::JIT)
    458       WhichEngine = EngineKind::JIT;
    459     else {
    460       if (ErrorStr)
    461         *ErrorStr = "Cannot create an interpreter with a memory manager.";
    462       return 0;
    463     }
    464   }
    465 
    466   // Unless the interpreter was explicitly selected or the JIT is not linked,
    467   // try making a JIT.
    468   if (WhichEngine & EngineKind::JIT) {
    469     if (TargetMachine *TM = EngineBuilder::selectTarget(M, MArch, MCPU, MAttrs,
    470                                                         RelocModel, ErrorStr)) {
    471       TM->setCodeModel(CMModel);
    472 
    473       if (UseMCJIT && ExecutionEngine::MCJITCtor) {
    474         ExecutionEngine *EE =
    475           ExecutionEngine::MCJITCtor(M, ErrorStr, JMM, OptLevel,
    476                                      AllocateGVsWithCode, TM);
    477         if (EE) return EE;
    478       } else if (ExecutionEngine::JITCtor) {
    479         ExecutionEngine *EE =
    480           ExecutionEngine::JITCtor(M, ErrorStr, JMM, OptLevel,
    481                                    AllocateGVsWithCode, TM);
    482         if (EE) return EE;
    483       }
    484     }
    485   }
    486 
    487   // If we can't make a JIT and we didn't request one specifically, try making
    488   // an interpreter instead.
    489   if (WhichEngine & EngineKind::Interpreter) {
    490     if (ExecutionEngine::InterpCtor)
    491       return ExecutionEngine::InterpCtor(M, ErrorStr);
    492     if (ErrorStr)
    493       *ErrorStr = "Interpreter has not been linked in.";
    494     return 0;
    495   }
    496 
    497   if ((WhichEngine & EngineKind::JIT) && ExecutionEngine::JITCtor == 0) {
    498     if (ErrorStr)
    499       *ErrorStr = "JIT has not been linked in.";
    500   }
    501 
    502   return 0;
    503 }
    504 
    505 void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
    506   if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
    507     return getPointerToFunction(F);
    508 
    509   MutexGuard locked(lock);
    510   if (void *P = EEState.getGlobalAddressMap(locked)[GV])
    511     return P;
    512 
    513   // Global variable might have been added since interpreter started.
    514   if (GlobalVariable *GVar =
    515           const_cast<GlobalVariable *>(dyn_cast<GlobalVariable>(GV)))
    516     EmitGlobalVariable(GVar);
    517   else
    518     llvm_unreachable("Global hasn't had an address allocated yet!");
    519 
    520   return EEState.getGlobalAddressMap(locked)[GV];
    521 }
    522 
    523 /// \brief Converts a Constant* into a GenericValue, including handling of
    524 /// ConstantExpr values.
    525 GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
    526   // If its undefined, return the garbage.
    527   if (isa<UndefValue>(C)) {
    528     GenericValue Result;
    529     switch (C->getType()->getTypeID()) {
    530     case Type::IntegerTyID:
    531     case Type::X86_FP80TyID:
    532     case Type::FP128TyID:
    533     case Type::PPC_FP128TyID:
    534       // Although the value is undefined, we still have to construct an APInt
    535       // with the correct bit width.
    536       Result.IntVal = APInt(C->getType()->getPrimitiveSizeInBits(), 0);
    537       break;
    538     default:
    539       break;
    540     }
    541     return Result;
    542   }
    543 
    544   // Otherwise, if the value is a ConstantExpr...
    545   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
    546     Constant *Op0 = CE->getOperand(0);
    547     switch (CE->getOpcode()) {
    548     case Instruction::GetElementPtr: {
    549       // Compute the index
    550       GenericValue Result = getConstantValue(Op0);
    551       SmallVector<Value*, 8> Indices(CE->op_begin()+1, CE->op_end());
    552       uint64_t Offset = TD->getIndexedOffset(Op0->getType(), Indices);
    553 
    554       char* tmp = (char*) Result.PointerVal;
    555       Result = PTOGV(tmp + Offset);
    556       return Result;
    557     }
    558     case Instruction::Trunc: {
    559       GenericValue GV = getConstantValue(Op0);
    560       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    561       GV.IntVal = GV.IntVal.trunc(BitWidth);
    562       return GV;
    563     }
    564     case Instruction::ZExt: {
    565       GenericValue GV = getConstantValue(Op0);
    566       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    567       GV.IntVal = GV.IntVal.zext(BitWidth);
    568       return GV;
    569     }
    570     case Instruction::SExt: {
    571       GenericValue GV = getConstantValue(Op0);
    572       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    573       GV.IntVal = GV.IntVal.sext(BitWidth);
    574       return GV;
    575     }
    576     case Instruction::FPTrunc: {
    577       // FIXME long double
    578       GenericValue GV = getConstantValue(Op0);
    579       GV.FloatVal = float(GV.DoubleVal);
    580       return GV;
    581     }
    582     case Instruction::FPExt:{
    583       // FIXME long double
    584       GenericValue GV = getConstantValue(Op0);
    585       GV.DoubleVal = double(GV.FloatVal);
    586       return GV;
    587     }
    588     case Instruction::UIToFP: {
    589       GenericValue GV = getConstantValue(Op0);
    590       if (CE->getType()->isFloatTy())
    591         GV.FloatVal = float(GV.IntVal.roundToDouble());
    592       else if (CE->getType()->isDoubleTy())
    593         GV.DoubleVal = GV.IntVal.roundToDouble();
    594       else if (CE->getType()->isX86_FP80Ty()) {
    595         APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended);
    596         (void)apf.convertFromAPInt(GV.IntVal,
    597                                    false,
    598                                    APFloat::rmNearestTiesToEven);
    599         GV.IntVal = apf.bitcastToAPInt();
    600       }
    601       return GV;
    602     }
    603     case Instruction::SIToFP: {
    604       GenericValue GV = getConstantValue(Op0);
    605       if (CE->getType()->isFloatTy())
    606         GV.FloatVal = float(GV.IntVal.signedRoundToDouble());
    607       else if (CE->getType()->isDoubleTy())
    608         GV.DoubleVal = GV.IntVal.signedRoundToDouble();
    609       else if (CE->getType()->isX86_FP80Ty()) {
    610         APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended);
    611         (void)apf.convertFromAPInt(GV.IntVal,
    612                                    true,
    613                                    APFloat::rmNearestTiesToEven);
    614         GV.IntVal = apf.bitcastToAPInt();
    615       }
    616       return GV;
    617     }
    618     case Instruction::FPToUI: // double->APInt conversion handles sign
    619     case Instruction::FPToSI: {
    620       GenericValue GV = getConstantValue(Op0);
    621       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    622       if (Op0->getType()->isFloatTy())
    623         GV.IntVal = APIntOps::RoundFloatToAPInt(GV.FloatVal, BitWidth);
    624       else if (Op0->getType()->isDoubleTy())
    625         GV.IntVal = APIntOps::RoundDoubleToAPInt(GV.DoubleVal, BitWidth);
    626       else if (Op0->getType()->isX86_FP80Ty()) {
    627         APFloat apf = APFloat(GV.IntVal);
    628         uint64_t v;
    629         bool ignored;
    630         (void)apf.convertToInteger(&v, BitWidth,
    631                                    CE->getOpcode()==Instruction::FPToSI,
    632                                    APFloat::rmTowardZero, &ignored);
    633         GV.IntVal = v; // endian?
    634       }
    635       return GV;
    636     }
    637     case Instruction::PtrToInt: {
    638       GenericValue GV = getConstantValue(Op0);
    639       uint32_t PtrWidth = TD->getPointerSizeInBits();
    640       GV.IntVal = APInt(PtrWidth, uintptr_t(GV.PointerVal));
    641       return GV;
    642     }
    643     case Instruction::IntToPtr: {
    644       GenericValue GV = getConstantValue(Op0);
    645       uint32_t PtrWidth = TD->getPointerSizeInBits();
    646       if (PtrWidth != GV.IntVal.getBitWidth())
    647         GV.IntVal = GV.IntVal.zextOrTrunc(PtrWidth);
    648       assert(GV.IntVal.getBitWidth() <= 64 && "Bad pointer width");
    649       GV.PointerVal = PointerTy(uintptr_t(GV.IntVal.getZExtValue()));
    650       return GV;
    651     }
    652     case Instruction::BitCast: {
    653       GenericValue GV = getConstantValue(Op0);
    654       Type* DestTy = CE->getType();
    655       switch (Op0->getType()->getTypeID()) {
    656         default: llvm_unreachable("Invalid bitcast operand");
    657         case Type::IntegerTyID:
    658           assert(DestTy->isFloatingPointTy() && "invalid bitcast");
    659           if (DestTy->isFloatTy())
    660             GV.FloatVal = GV.IntVal.bitsToFloat();
    661           else if (DestTy->isDoubleTy())
    662             GV.DoubleVal = GV.IntVal.bitsToDouble();
    663           break;
    664         case Type::FloatTyID:
    665           assert(DestTy->isIntegerTy(32) && "Invalid bitcast");
    666           GV.IntVal = APInt::floatToBits(GV.FloatVal);
    667           break;
    668         case Type::DoubleTyID:
    669           assert(DestTy->isIntegerTy(64) && "Invalid bitcast");
    670           GV.IntVal = APInt::doubleToBits(GV.DoubleVal);
    671           break;
    672         case Type::PointerTyID:
    673           assert(DestTy->isPointerTy() && "Invalid bitcast");
    674           break; // getConstantValue(Op0)  above already converted it
    675       }
    676       return GV;
    677     }
    678     case Instruction::Add:
    679     case Instruction::FAdd:
    680     case Instruction::Sub:
    681     case Instruction::FSub:
    682     case Instruction::Mul:
    683     case Instruction::FMul:
    684     case Instruction::UDiv:
    685     case Instruction::SDiv:
    686     case Instruction::URem:
    687     case Instruction::SRem:
    688     case Instruction::And:
    689     case Instruction::Or:
    690     case Instruction::Xor: {
    691       GenericValue LHS = getConstantValue(Op0);
    692       GenericValue RHS = getConstantValue(CE->getOperand(1));
    693       GenericValue GV;
    694       switch (CE->getOperand(0)->getType()->getTypeID()) {
    695       default: llvm_unreachable("Bad add type!");
    696       case Type::IntegerTyID:
    697         switch (CE->getOpcode()) {
    698           default: llvm_unreachable("Invalid integer opcode");
    699           case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
    700           case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
    701           case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
    702           case Instruction::UDiv:GV.IntVal = LHS.IntVal.udiv(RHS.IntVal); break;
    703           case Instruction::SDiv:GV.IntVal = LHS.IntVal.sdiv(RHS.IntVal); break;
    704           case Instruction::URem:GV.IntVal = LHS.IntVal.urem(RHS.IntVal); break;
    705           case Instruction::SRem:GV.IntVal = LHS.IntVal.srem(RHS.IntVal); break;
    706           case Instruction::And: GV.IntVal = LHS.IntVal & RHS.IntVal; break;
    707           case Instruction::Or:  GV.IntVal = LHS.IntVal | RHS.IntVal; break;
    708           case Instruction::Xor: GV.IntVal = LHS.IntVal ^ RHS.IntVal; break;
    709         }
    710         break;
    711       case Type::FloatTyID:
    712         switch (CE->getOpcode()) {
    713           default: llvm_unreachable("Invalid float opcode");
    714           case Instruction::FAdd:
    715             GV.FloatVal = LHS.FloatVal + RHS.FloatVal; break;
    716           case Instruction::FSub:
    717             GV.FloatVal = LHS.FloatVal - RHS.FloatVal; break;
    718           case Instruction::FMul:
    719             GV.FloatVal = LHS.FloatVal * RHS.FloatVal; break;
    720           case Instruction::FDiv:
    721             GV.FloatVal = LHS.FloatVal / RHS.FloatVal; break;
    722           case Instruction::FRem:
    723             GV.FloatVal = std::fmod(LHS.FloatVal,RHS.FloatVal); break;
    724         }
    725         break;
    726       case Type::DoubleTyID:
    727         switch (CE->getOpcode()) {
    728           default: llvm_unreachable("Invalid double opcode");
    729           case Instruction::FAdd:
    730             GV.DoubleVal = LHS.DoubleVal + RHS.DoubleVal; break;
    731           case Instruction::FSub:
    732             GV.DoubleVal = LHS.DoubleVal - RHS.DoubleVal; break;
    733           case Instruction::FMul:
    734             GV.DoubleVal = LHS.DoubleVal * RHS.DoubleVal; break;
    735           case Instruction::FDiv:
    736             GV.DoubleVal = LHS.DoubleVal / RHS.DoubleVal; break;
    737           case Instruction::FRem:
    738             GV.DoubleVal = std::fmod(LHS.DoubleVal,RHS.DoubleVal); break;
    739         }
    740         break;
    741       case Type::X86_FP80TyID:
    742       case Type::PPC_FP128TyID:
    743       case Type::FP128TyID: {
    744         APFloat apfLHS = APFloat(LHS.IntVal);
    745         switch (CE->getOpcode()) {
    746           default: llvm_unreachable("Invalid long double opcode");
    747           case Instruction::FAdd:
    748             apfLHS.add(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    749             GV.IntVal = apfLHS.bitcastToAPInt();
    750             break;
    751           case Instruction::FSub:
    752             apfLHS.subtract(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    753             GV.IntVal = apfLHS.bitcastToAPInt();
    754             break;
    755           case Instruction::FMul:
    756             apfLHS.multiply(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    757             GV.IntVal = apfLHS.bitcastToAPInt();
    758             break;
    759           case Instruction::FDiv:
    760             apfLHS.divide(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    761             GV.IntVal = apfLHS.bitcastToAPInt();
    762             break;
    763           case Instruction::FRem:
    764             apfLHS.mod(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    765             GV.IntVal = apfLHS.bitcastToAPInt();
    766             break;
    767           }
    768         }
    769         break;
    770       }
    771       return GV;
    772     }
    773     default:
    774       break;
    775     }
    776 
    777     SmallString<256> Msg;
    778     raw_svector_ostream OS(Msg);
    779     OS << "ConstantExpr not handled: " << *CE;
    780     report_fatal_error(OS.str());
    781   }
    782 
    783   // Otherwise, we have a simple constant.
    784   GenericValue Result;
    785   switch (C->getType()->getTypeID()) {
    786   case Type::FloatTyID:
    787     Result.FloatVal = cast<ConstantFP>(C)->getValueAPF().convertToFloat();
    788     break;
    789   case Type::DoubleTyID:
    790     Result.DoubleVal = cast<ConstantFP>(C)->getValueAPF().convertToDouble();
    791     break;
    792   case Type::X86_FP80TyID:
    793   case Type::FP128TyID:
    794   case Type::PPC_FP128TyID:
    795     Result.IntVal = cast <ConstantFP>(C)->getValueAPF().bitcastToAPInt();
    796     break;
    797   case Type::IntegerTyID:
    798     Result.IntVal = cast<ConstantInt>(C)->getValue();
    799     break;
    800   case Type::PointerTyID:
    801     if (isa<ConstantPointerNull>(C))
    802       Result.PointerVal = 0;
    803     else if (const Function *F = dyn_cast<Function>(C))
    804       Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
    805     else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
    806       Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
    807     else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C))
    808       Result = PTOGV(getPointerToBasicBlock(const_cast<BasicBlock*>(
    809                                                         BA->getBasicBlock())));
    810     else
    811       llvm_unreachable("Unknown constant pointer type!");
    812     break;
    813   default:
    814     SmallString<256> Msg;
    815     raw_svector_ostream OS(Msg);
    816     OS << "ERROR: Constant unimplemented for type: " << *C->getType();
    817     report_fatal_error(OS.str());
    818   }
    819 
    820   return Result;
    821 }
    822 
    823 /// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
    824 /// with the integer held in IntVal.
    825 static void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
    826                              unsigned StoreBytes) {
    827   assert((IntVal.getBitWidth()+7)/8 >= StoreBytes && "Integer too small!");
    828   uint8_t *Src = (uint8_t *)IntVal.getRawData();
    829 
    830   if (sys::isLittleEndianHost()) {
    831     // Little-endian host - the source is ordered from LSB to MSB.  Order the
    832     // destination from LSB to MSB: Do a straight copy.
    833     memcpy(Dst, Src, StoreBytes);
    834   } else {
    835     // Big-endian host - the source is an array of 64 bit words ordered from
    836     // LSW to MSW.  Each word is ordered from MSB to LSB.  Order the destination
    837     // from MSB to LSB: Reverse the word order, but not the bytes in a word.
    838     while (StoreBytes > sizeof(uint64_t)) {
    839       StoreBytes -= sizeof(uint64_t);
    840       // May not be aligned so use memcpy.
    841       memcpy(Dst + StoreBytes, Src, sizeof(uint64_t));
    842       Src += sizeof(uint64_t);
    843     }
    844 
    845     memcpy(Dst, Src + sizeof(uint64_t) - StoreBytes, StoreBytes);
    846   }
    847 }
    848 
    849 void ExecutionEngine::StoreValueToMemory(const GenericValue &Val,
    850                                          GenericValue *Ptr, Type *Ty) {
    851   const unsigned StoreBytes = getTargetData()->getTypeStoreSize(Ty);
    852 
    853   switch (Ty->getTypeID()) {
    854   case Type::IntegerTyID:
    855     StoreIntToMemory(Val.IntVal, (uint8_t*)Ptr, StoreBytes);
    856     break;
    857   case Type::FloatTyID:
    858     *((float*)Ptr) = Val.FloatVal;
    859     break;
    860   case Type::DoubleTyID:
    861     *((double*)Ptr) = Val.DoubleVal;
    862     break;
    863   case Type::X86_FP80TyID:
    864     memcpy(Ptr, Val.IntVal.getRawData(), 10);
    865     break;
    866   case Type::PointerTyID:
    867     // Ensure 64 bit target pointers are fully initialized on 32 bit hosts.
    868     if (StoreBytes != sizeof(PointerTy))
    869       memset(&(Ptr->PointerVal), 0, StoreBytes);
    870 
    871     *((PointerTy*)Ptr) = Val.PointerVal;
    872     break;
    873   default:
    874     dbgs() << "Cannot store value of type " << *Ty << "!\n";
    875   }
    876 
    877   if (sys::isLittleEndianHost() != getTargetData()->isLittleEndian())
    878     // Host and target are different endian - reverse the stored bytes.
    879     std::reverse((uint8_t*)Ptr, StoreBytes + (uint8_t*)Ptr);
    880 }
    881 
    882 /// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
    883 /// from Src into IntVal, which is assumed to be wide enough and to hold zero.
    884 static void LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes) {
    885   assert((IntVal.getBitWidth()+7)/8 >= LoadBytes && "Integer too small!");
    886   uint8_t *Dst = (uint8_t *)IntVal.getRawData();
    887 
    888   if (sys::isLittleEndianHost())
    889     // Little-endian host - the destination must be ordered from LSB to MSB.
    890     // The source is ordered from LSB to MSB: Do a straight copy.
    891     memcpy(Dst, Src, LoadBytes);
    892   else {
    893     // Big-endian - the destination is an array of 64 bit words ordered from
    894     // LSW to MSW.  Each word must be ordered from MSB to LSB.  The source is
    895     // ordered from MSB to LSB: Reverse the word order, but not the bytes in
    896     // a word.
    897     while (LoadBytes > sizeof(uint64_t)) {
    898       LoadBytes -= sizeof(uint64_t);
    899       // May not be aligned so use memcpy.
    900       memcpy(Dst, Src + LoadBytes, sizeof(uint64_t));
    901       Dst += sizeof(uint64_t);
    902     }
    903 
    904     memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
    905   }
    906 }
    907 
    908 /// FIXME: document
    909 ///
    910 void ExecutionEngine::LoadValueFromMemory(GenericValue &Result,
    911                                           GenericValue *Ptr,
    912                                           Type *Ty) {
    913   const unsigned LoadBytes = getTargetData()->getTypeStoreSize(Ty);
    914 
    915   switch (Ty->getTypeID()) {
    916   case Type::IntegerTyID:
    917     // An APInt with all words initially zero.
    918     Result.IntVal = APInt(cast<IntegerType>(Ty)->getBitWidth(), 0);
    919     LoadIntFromMemory(Result.IntVal, (uint8_t*)Ptr, LoadBytes);
    920     break;
    921   case Type::FloatTyID:
    922     Result.FloatVal = *((float*)Ptr);
    923     break;
    924   case Type::DoubleTyID:
    925     Result.DoubleVal = *((double*)Ptr);
    926     break;
    927   case Type::PointerTyID:
    928     Result.PointerVal = *((PointerTy*)Ptr);
    929     break;
    930   case Type::X86_FP80TyID: {
    931     // This is endian dependent, but it will only work on x86 anyway.
    932     // FIXME: Will not trap if loading a signaling NaN.
    933     uint64_t y[2];
    934     memcpy(y, Ptr, 10);
    935     Result.IntVal = APInt(80, y);
    936     break;
    937   }
    938   default:
    939     SmallString<256> Msg;
    940     raw_svector_ostream OS(Msg);
    941     OS << "Cannot load value of type " << *Ty << "!";
    942     report_fatal_error(OS.str());
    943   }
    944 }
    945 
    946 void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
    947   DEBUG(dbgs() << "JIT: Initializing " << Addr << " ");
    948   DEBUG(Init->dump());
    949   if (isa<UndefValue>(Init)) {
    950     return;
    951   } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(Init)) {
    952     unsigned ElementSize =
    953       getTargetData()->getTypeAllocSize(CP->getType()->getElementType());
    954     for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
    955       InitializeMemory(CP->getOperand(i), (char*)Addr+i*ElementSize);
    956     return;
    957   } else if (isa<ConstantAggregateZero>(Init)) {
    958     memset(Addr, 0, (size_t)getTargetData()->getTypeAllocSize(Init->getType()));
    959     return;
    960   } else if (const ConstantArray *CPA = dyn_cast<ConstantArray>(Init)) {
    961     unsigned ElementSize =
    962       getTargetData()->getTypeAllocSize(CPA->getType()->getElementType());
    963     for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
    964       InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
    965     return;
    966   } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(Init)) {
    967     const StructLayout *SL =
    968       getTargetData()->getStructLayout(cast<StructType>(CPS->getType()));
    969     for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
    970       InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->getElementOffset(i));
    971     return;
    972   } else if (Init->getType()->isFirstClassType()) {
    973     GenericValue Val = getConstantValue(Init);
    974     StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
    975     return;
    976   }
    977 
    978   DEBUG(dbgs() << "Bad Type: " << *Init->getType() << "\n");
    979   llvm_unreachable("Unknown constant type to initialize memory with!");
    980 }
    981 
    982 /// EmitGlobals - Emit all of the global variables to memory, storing their
    983 /// addresses into GlobalAddress.  This must make sure to copy the contents of
    984 /// their initializers into the memory.
    985 void ExecutionEngine::emitGlobals() {
    986   // Loop over all of the global variables in the program, allocating the memory
    987   // to hold them.  If there is more than one module, do a prepass over globals
    988   // to figure out how the different modules should link together.
    989   std::map<std::pair<std::string, Type*>,
    990            const GlobalValue*> LinkedGlobalsMap;
    991 
    992   if (Modules.size() != 1) {
    993     for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
    994       Module &M = *Modules[m];
    995       for (Module::const_global_iterator I = M.global_begin(),
    996            E = M.global_end(); I != E; ++I) {
    997         const GlobalValue *GV = I;
    998         if (GV->hasLocalLinkage() || GV->isDeclaration() ||
    999             GV->hasAppendingLinkage() || !GV->hasName())
   1000           continue;// Ignore external globals and globals with internal linkage.
   1001 
   1002         const GlobalValue *&GVEntry =
   1003           LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
   1004 
   1005         // If this is the first time we've seen this global, it is the canonical
   1006         // version.
   1007         if (!GVEntry) {
   1008           GVEntry = GV;
   1009           continue;
   1010         }
   1011 
   1012         // If the existing global is strong, never replace it.
   1013         if (GVEntry->hasExternalLinkage() ||
   1014             GVEntry->hasDLLImportLinkage() ||
   1015             GVEntry->hasDLLExportLinkage())
   1016           continue;
   1017 
   1018         // Otherwise, we know it's linkonce/weak, replace it if this is a strong
   1019         // symbol.  FIXME is this right for common?
   1020         if (GV->hasExternalLinkage() || GVEntry->hasExternalWeakLinkage())
   1021           GVEntry = GV;
   1022       }
   1023     }
   1024   }
   1025 
   1026   std::vector<const GlobalValue*> NonCanonicalGlobals;
   1027   for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
   1028     Module &M = *Modules[m];
   1029     for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
   1030          I != E; ++I) {
   1031       // In the multi-module case, see what this global maps to.
   1032       if (!LinkedGlobalsMap.empty()) {
   1033         if (const GlobalValue *GVEntry =
   1034               LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())]) {
   1035           // If something else is the canonical global, ignore this one.
   1036           if (GVEntry != &*I) {
   1037             NonCanonicalGlobals.push_back(I);
   1038             continue;
   1039           }
   1040         }
   1041       }
   1042 
   1043       if (!I->isDeclaration()) {
   1044         addGlobalMapping(I, getMemoryForGV(I));
   1045       } else {
   1046         // External variable reference. Try to use the dynamic loader to
   1047         // get a pointer to it.
   1048         if (void *SymAddr =
   1049             sys::DynamicLibrary::SearchForAddressOfSymbol(I->getName()))
   1050           addGlobalMapping(I, SymAddr);
   1051         else {
   1052           report_fatal_error("Could not resolve external global address: "
   1053                             +I->getName());
   1054         }
   1055       }
   1056     }
   1057 
   1058     // If there are multiple modules, map the non-canonical globals to their
   1059     // canonical location.
   1060     if (!NonCanonicalGlobals.empty()) {
   1061       for (unsigned i = 0, e = NonCanonicalGlobals.size(); i != e; ++i) {
   1062         const GlobalValue *GV = NonCanonicalGlobals[i];
   1063         const GlobalValue *CGV =
   1064           LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
   1065         void *Ptr = getPointerToGlobalIfAvailable(CGV);
   1066         assert(Ptr && "Canonical global wasn't codegen'd!");
   1067         addGlobalMapping(GV, Ptr);
   1068       }
   1069     }
   1070 
   1071     // Now that all of the globals are set up in memory, loop through them all
   1072     // and initialize their contents.
   1073     for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
   1074          I != E; ++I) {
   1075       if (!I->isDeclaration()) {
   1076         if (!LinkedGlobalsMap.empty()) {
   1077           if (const GlobalValue *GVEntry =
   1078                 LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())])
   1079             if (GVEntry != &*I)  // Not the canonical variable.
   1080               continue;
   1081         }
   1082         EmitGlobalVariable(I);
   1083       }
   1084     }
   1085   }
   1086 }
   1087 
   1088 // EmitGlobalVariable - This method emits the specified global variable to the
   1089 // address specified in GlobalAddresses, or allocates new memory if it's not
   1090 // already in the map.
   1091 void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
   1092   void *GA = getPointerToGlobalIfAvailable(GV);
   1093 
   1094   if (GA == 0) {
   1095     // If it's not already specified, allocate memory for the global.
   1096     GA = getMemoryForGV(GV);
   1097     addGlobalMapping(GV, GA);
   1098   }
   1099 
   1100   // Don't initialize if it's thread local, let the client do it.
   1101   if (!GV->isThreadLocal())
   1102     InitializeMemory(GV->getInitializer(), GA);
   1103 
   1104   Type *ElTy = GV->getType()->getElementType();
   1105   size_t GVSize = (size_t)getTargetData()->getTypeAllocSize(ElTy);
   1106   NumInitBytes += (unsigned)GVSize;
   1107   ++NumGlobals;
   1108 }
   1109 
   1110 ExecutionEngineState::ExecutionEngineState(ExecutionEngine &EE)
   1111   : EE(EE), GlobalAddressMap(this) {
   1112 }
   1113 
   1114 sys::Mutex *
   1115 ExecutionEngineState::AddressMapConfig::getMutex(ExecutionEngineState *EES) {
   1116   return &EES->EE.lock;
   1117 }
   1118 
   1119 void ExecutionEngineState::AddressMapConfig::onDelete(ExecutionEngineState *EES,
   1120                                                       const GlobalValue *Old) {
   1121   void *OldVal = EES->GlobalAddressMap.lookup(Old);
   1122   EES->GlobalAddressReverseMap.erase(OldVal);
   1123 }
   1124 
   1125 void ExecutionEngineState::AddressMapConfig::onRAUW(ExecutionEngineState *,
   1126                                                     const GlobalValue *,
   1127                                                     const GlobalValue *) {
   1128   assert(false && "The ExecutionEngine doesn't know how to handle a"
   1129          " RAUW on a value it has a global mapping for.");
   1130 }
   1131