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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/Support/TargetRegistry.h"
     32 #include "llvm/Target/TargetData.h"
     33 #include "llvm/Target/TargetMachine.h"
     34 #include <cmath>
     35 #include <cstring>
     36 using namespace llvm;
     37 
     38 STATISTIC(NumInitBytes, "Number of bytes of global vars initialized");
     39 STATISTIC(NumGlobals  , "Number of global vars initialized");
     40 
     41 ExecutionEngine *(*ExecutionEngine::JITCtor)(
     42   Module *M,
     43   std::string *ErrorStr,
     44   JITMemoryManager *JMM,
     45   bool GVsWithCode,
     46   TargetMachine *TM) = 0;
     47 ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
     48   Module *M,
     49   std::string *ErrorStr,
     50   JITMemoryManager *JMM,
     51   bool GVsWithCode,
     52   TargetMachine *TM) = 0;
     53 ExecutionEngine *(*ExecutionEngine::InterpCtor)(Module *M,
     54                                                 std::string *ErrorStr) = 0;
     55 
     56 ExecutionEngine::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 
     68 ExecutionEngine::~ExecutionEngine() {
     69   clearAllGlobalMappings();
     70   for (unsigned i = 0, e = Modules.size(); i != e; ++i)
     71     delete Modules[i];
     72 }
     73 
     74 void 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 
     84 namespace {
     85 /// \brief Helper class which uses a value handler to automatically deletes the
     86 /// memory block when the GlobalVariable is destroyed.
     87 class GVMemoryBlock : public CallbackVH {
     88   GVMemoryBlock(const GlobalVariable *GV)
     89     : CallbackVH(const_cast<GlobalVariable*>(GV)) {}
     90 
     91 public:
     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 TargetData& TD) {
     95     Type *ElTy = GV->getType()->getElementType();
     96     size_t GVSize = (size_t)TD.getTypeAllocSize(ElTy);
     97     void *RawMemory = ::operator new(
     98       TargetData::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 
    115 char *ExecutionEngine::getMemoryForGV(const GlobalVariable *GV) {
    116   return GVMemoryBlock::Create(GV, *getTargetData());
    117 }
    118 
    119 bool 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 
    132 Function *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 
    141 void *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 
    159 void 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 
    177 void ExecutionEngine::clearAllGlobalMappings() {
    178   MutexGuard locked(lock);
    179 
    180   EEState.getGlobalAddressMap(locked).clear();
    181   EEState.getGlobalAddressReverseMap(locked).clear();
    182 }
    183 
    184 void 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 
    194 void *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 
    221 void *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 
    229 const 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 
    246 namespace {
    247 class ArgvArray {
    248   char *Array;
    249   std::vector<char*> Values;
    250 public:
    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
    267 void *ArgvArray::reset(LLVMContext &C, ExecutionEngine *EE,
    268                        const std::vector<std::string> &InputArgv) {
    269   clear();  // Free the old contents.
    270   unsigned PtrSize = EE->getTargetData()->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 
    297 void 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 
    336 void 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.
    344 static bool isTargetNullPtr(ExecutionEngine *EE, void *Loc) {
    345   unsigned PtrSize = EE->getTargetData()->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 
    353 int 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 
    400 ExecutionEngine *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.
    419 ExecutionEngine *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 
    450 ExecutionEngine *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     if (ErrorStr)
    506       *ErrorStr = "JIT has not been linked in.";
    507   }
    508 
    509   return 0;
    510 }
    511 
    512 void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
    513   if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
    514     return getPointerToFunction(F);
    515 
    516   MutexGuard locked(lock);
    517   if (void *P = EEState.getGlobalAddressMap(locked)[GV])
    518     return P;
    519 
    520   // Global variable might have been added since interpreter started.
    521   if (GlobalVariable *GVar =
    522           const_cast<GlobalVariable *>(dyn_cast<GlobalVariable>(GV)))
    523     EmitGlobalVariable(GVar);
    524   else
    525     llvm_unreachable("Global hasn't had an address allocated yet!");
    526 
    527   return EEState.getGlobalAddressMap(locked)[GV];
    528 }
    529 
    530 /// \brief Converts a Constant* into a GenericValue, including handling of
    531 /// ConstantExpr values.
    532 GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
    533   // If its undefined, return the garbage.
    534   if (isa<UndefValue>(C)) {
    535     GenericValue Result;
    536     switch (C->getType()->getTypeID()) {
    537     case Type::IntegerTyID:
    538     case Type::X86_FP80TyID:
    539     case Type::FP128TyID:
    540     case Type::PPC_FP128TyID:
    541       // Although the value is undefined, we still have to construct an APInt
    542       // with the correct bit width.
    543       Result.IntVal = APInt(C->getType()->getPrimitiveSizeInBits(), 0);
    544       break;
    545     default:
    546       break;
    547     }
    548     return Result;
    549   }
    550 
    551   // Otherwise, if the value is a ConstantExpr...
    552   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
    553     Constant *Op0 = CE->getOperand(0);
    554     switch (CE->getOpcode()) {
    555     case Instruction::GetElementPtr: {
    556       // Compute the index
    557       GenericValue Result = getConstantValue(Op0);
    558       SmallVector<Value*, 8> Indices(CE->op_begin()+1, CE->op_end());
    559       uint64_t Offset = TD->getIndexedOffset(Op0->getType(), Indices);
    560 
    561       char* tmp = (char*) Result.PointerVal;
    562       Result = PTOGV(tmp + Offset);
    563       return Result;
    564     }
    565     case Instruction::Trunc: {
    566       GenericValue GV = getConstantValue(Op0);
    567       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    568       GV.IntVal = GV.IntVal.trunc(BitWidth);
    569       return GV;
    570     }
    571     case Instruction::ZExt: {
    572       GenericValue GV = getConstantValue(Op0);
    573       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    574       GV.IntVal = GV.IntVal.zext(BitWidth);
    575       return GV;
    576     }
    577     case Instruction::SExt: {
    578       GenericValue GV = getConstantValue(Op0);
    579       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    580       GV.IntVal = GV.IntVal.sext(BitWidth);
    581       return GV;
    582     }
    583     case Instruction::FPTrunc: {
    584       // FIXME long double
    585       GenericValue GV = getConstantValue(Op0);
    586       GV.FloatVal = float(GV.DoubleVal);
    587       return GV;
    588     }
    589     case Instruction::FPExt:{
    590       // FIXME long double
    591       GenericValue GV = getConstantValue(Op0);
    592       GV.DoubleVal = double(GV.FloatVal);
    593       return GV;
    594     }
    595     case Instruction::UIToFP: {
    596       GenericValue GV = getConstantValue(Op0);
    597       if (CE->getType()->isFloatTy())
    598         GV.FloatVal = float(GV.IntVal.roundToDouble());
    599       else if (CE->getType()->isDoubleTy())
    600         GV.DoubleVal = GV.IntVal.roundToDouble();
    601       else if (CE->getType()->isX86_FP80Ty()) {
    602         APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended);
    603         (void)apf.convertFromAPInt(GV.IntVal,
    604                                    false,
    605                                    APFloat::rmNearestTiesToEven);
    606         GV.IntVal = apf.bitcastToAPInt();
    607       }
    608       return GV;
    609     }
    610     case Instruction::SIToFP: {
    611       GenericValue GV = getConstantValue(Op0);
    612       if (CE->getType()->isFloatTy())
    613         GV.FloatVal = float(GV.IntVal.signedRoundToDouble());
    614       else if (CE->getType()->isDoubleTy())
    615         GV.DoubleVal = GV.IntVal.signedRoundToDouble();
    616       else if (CE->getType()->isX86_FP80Ty()) {
    617         APFloat apf = APFloat::getZero(APFloat::x87DoubleExtended);
    618         (void)apf.convertFromAPInt(GV.IntVal,
    619                                    true,
    620                                    APFloat::rmNearestTiesToEven);
    621         GV.IntVal = apf.bitcastToAPInt();
    622       }
    623       return GV;
    624     }
    625     case Instruction::FPToUI: // double->APInt conversion handles sign
    626     case Instruction::FPToSI: {
    627       GenericValue GV = getConstantValue(Op0);
    628       uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
    629       if (Op0->getType()->isFloatTy())
    630         GV.IntVal = APIntOps::RoundFloatToAPInt(GV.FloatVal, BitWidth);
    631       else if (Op0->getType()->isDoubleTy())
    632         GV.IntVal = APIntOps::RoundDoubleToAPInt(GV.DoubleVal, BitWidth);
    633       else if (Op0->getType()->isX86_FP80Ty()) {
    634         APFloat apf = APFloat(GV.IntVal);
    635         uint64_t v;
    636         bool ignored;
    637         (void)apf.convertToInteger(&v, BitWidth,
    638                                    CE->getOpcode()==Instruction::FPToSI,
    639                                    APFloat::rmTowardZero, &ignored);
    640         GV.IntVal = v; // endian?
    641       }
    642       return GV;
    643     }
    644     case Instruction::PtrToInt: {
    645       GenericValue GV = getConstantValue(Op0);
    646       uint32_t PtrWidth = TD->getPointerSizeInBits();
    647       GV.IntVal = APInt(PtrWidth, uintptr_t(GV.PointerVal));
    648       return GV;
    649     }
    650     case Instruction::IntToPtr: {
    651       GenericValue GV = getConstantValue(Op0);
    652       uint32_t PtrWidth = TD->getPointerSizeInBits();
    653       if (PtrWidth != GV.IntVal.getBitWidth())
    654         GV.IntVal = GV.IntVal.zextOrTrunc(PtrWidth);
    655       assert(GV.IntVal.getBitWidth() <= 64 && "Bad pointer width");
    656       GV.PointerVal = PointerTy(uintptr_t(GV.IntVal.getZExtValue()));
    657       return GV;
    658     }
    659     case Instruction::BitCast: {
    660       GenericValue GV = getConstantValue(Op0);
    661       Type* DestTy = CE->getType();
    662       switch (Op0->getType()->getTypeID()) {
    663         default: llvm_unreachable("Invalid bitcast operand");
    664         case Type::IntegerTyID:
    665           assert(DestTy->isFloatingPointTy() && "invalid bitcast");
    666           if (DestTy->isFloatTy())
    667             GV.FloatVal = GV.IntVal.bitsToFloat();
    668           else if (DestTy->isDoubleTy())
    669             GV.DoubleVal = GV.IntVal.bitsToDouble();
    670           break;
    671         case Type::FloatTyID:
    672           assert(DestTy->isIntegerTy(32) && "Invalid bitcast");
    673           GV.IntVal = APInt::floatToBits(GV.FloatVal);
    674           break;
    675         case Type::DoubleTyID:
    676           assert(DestTy->isIntegerTy(64) && "Invalid bitcast");
    677           GV.IntVal = APInt::doubleToBits(GV.DoubleVal);
    678           break;
    679         case Type::PointerTyID:
    680           assert(DestTy->isPointerTy() && "Invalid bitcast");
    681           break; // getConstantValue(Op0)  above already converted it
    682       }
    683       return GV;
    684     }
    685     case Instruction::Add:
    686     case Instruction::FAdd:
    687     case Instruction::Sub:
    688     case Instruction::FSub:
    689     case Instruction::Mul:
    690     case Instruction::FMul:
    691     case Instruction::UDiv:
    692     case Instruction::SDiv:
    693     case Instruction::URem:
    694     case Instruction::SRem:
    695     case Instruction::And:
    696     case Instruction::Or:
    697     case Instruction::Xor: {
    698       GenericValue LHS = getConstantValue(Op0);
    699       GenericValue RHS = getConstantValue(CE->getOperand(1));
    700       GenericValue GV;
    701       switch (CE->getOperand(0)->getType()->getTypeID()) {
    702       default: llvm_unreachable("Bad add type!");
    703       case Type::IntegerTyID:
    704         switch (CE->getOpcode()) {
    705           default: llvm_unreachable("Invalid integer opcode");
    706           case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
    707           case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
    708           case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
    709           case Instruction::UDiv:GV.IntVal = LHS.IntVal.udiv(RHS.IntVal); break;
    710           case Instruction::SDiv:GV.IntVal = LHS.IntVal.sdiv(RHS.IntVal); break;
    711           case Instruction::URem:GV.IntVal = LHS.IntVal.urem(RHS.IntVal); break;
    712           case Instruction::SRem:GV.IntVal = LHS.IntVal.srem(RHS.IntVal); break;
    713           case Instruction::And: GV.IntVal = LHS.IntVal & RHS.IntVal; break;
    714           case Instruction::Or:  GV.IntVal = LHS.IntVal | RHS.IntVal; break;
    715           case Instruction::Xor: GV.IntVal = LHS.IntVal ^ RHS.IntVal; break;
    716         }
    717         break;
    718       case Type::FloatTyID:
    719         switch (CE->getOpcode()) {
    720           default: llvm_unreachable("Invalid float opcode");
    721           case Instruction::FAdd:
    722             GV.FloatVal = LHS.FloatVal + RHS.FloatVal; break;
    723           case Instruction::FSub:
    724             GV.FloatVal = LHS.FloatVal - RHS.FloatVal; break;
    725           case Instruction::FMul:
    726             GV.FloatVal = LHS.FloatVal * RHS.FloatVal; break;
    727           case Instruction::FDiv:
    728             GV.FloatVal = LHS.FloatVal / RHS.FloatVal; break;
    729           case Instruction::FRem:
    730             GV.FloatVal = std::fmod(LHS.FloatVal,RHS.FloatVal); break;
    731         }
    732         break;
    733       case Type::DoubleTyID:
    734         switch (CE->getOpcode()) {
    735           default: llvm_unreachable("Invalid double opcode");
    736           case Instruction::FAdd:
    737             GV.DoubleVal = LHS.DoubleVal + RHS.DoubleVal; break;
    738           case Instruction::FSub:
    739             GV.DoubleVal = LHS.DoubleVal - RHS.DoubleVal; break;
    740           case Instruction::FMul:
    741             GV.DoubleVal = LHS.DoubleVal * RHS.DoubleVal; break;
    742           case Instruction::FDiv:
    743             GV.DoubleVal = LHS.DoubleVal / RHS.DoubleVal; break;
    744           case Instruction::FRem:
    745             GV.DoubleVal = std::fmod(LHS.DoubleVal,RHS.DoubleVal); break;
    746         }
    747         break;
    748       case Type::X86_FP80TyID:
    749       case Type::PPC_FP128TyID:
    750       case Type::FP128TyID: {
    751         APFloat apfLHS = APFloat(LHS.IntVal);
    752         switch (CE->getOpcode()) {
    753           default: llvm_unreachable("Invalid long double opcode");
    754           case Instruction::FAdd:
    755             apfLHS.add(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    756             GV.IntVal = apfLHS.bitcastToAPInt();
    757             break;
    758           case Instruction::FSub:
    759             apfLHS.subtract(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    760             GV.IntVal = apfLHS.bitcastToAPInt();
    761             break;
    762           case Instruction::FMul:
    763             apfLHS.multiply(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    764             GV.IntVal = apfLHS.bitcastToAPInt();
    765             break;
    766           case Instruction::FDiv:
    767             apfLHS.divide(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    768             GV.IntVal = apfLHS.bitcastToAPInt();
    769             break;
    770           case Instruction::FRem:
    771             apfLHS.mod(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
    772             GV.IntVal = apfLHS.bitcastToAPInt();
    773             break;
    774           }
    775         }
    776         break;
    777       }
    778       return GV;
    779     }
    780     default:
    781       break;
    782     }
    783 
    784     SmallString<256> Msg;
    785     raw_svector_ostream OS(Msg);
    786     OS << "ConstantExpr not handled: " << *CE;
    787     report_fatal_error(OS.str());
    788   }
    789 
    790   // Otherwise, we have a simple constant.
    791   GenericValue Result;
    792   switch (C->getType()->getTypeID()) {
    793   case Type::FloatTyID:
    794     Result.FloatVal = cast<ConstantFP>(C)->getValueAPF().convertToFloat();
    795     break;
    796   case Type::DoubleTyID:
    797     Result.DoubleVal = cast<ConstantFP>(C)->getValueAPF().convertToDouble();
    798     break;
    799   case Type::X86_FP80TyID:
    800   case Type::FP128TyID:
    801   case Type::PPC_FP128TyID:
    802     Result.IntVal = cast <ConstantFP>(C)->getValueAPF().bitcastToAPInt();
    803     break;
    804   case Type::IntegerTyID:
    805     Result.IntVal = cast<ConstantInt>(C)->getValue();
    806     break;
    807   case Type::PointerTyID:
    808     if (isa<ConstantPointerNull>(C))
    809       Result.PointerVal = 0;
    810     else if (const Function *F = dyn_cast<Function>(C))
    811       Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
    812     else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
    813       Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
    814     else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C))
    815       Result = PTOGV(getPointerToBasicBlock(const_cast<BasicBlock*>(
    816                                                         BA->getBasicBlock())));
    817     else
    818       llvm_unreachable("Unknown constant pointer type!");
    819     break;
    820   default:
    821     SmallString<256> Msg;
    822     raw_svector_ostream OS(Msg);
    823     OS << "ERROR: Constant unimplemented for type: " << *C->getType();
    824     report_fatal_error(OS.str());
    825   }
    826 
    827   return Result;
    828 }
    829 
    830 /// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
    831 /// with the integer held in IntVal.
    832 static void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
    833                              unsigned StoreBytes) {
    834   assert((IntVal.getBitWidth()+7)/8 >= StoreBytes && "Integer too small!");
    835   uint8_t *Src = (uint8_t *)IntVal.getRawData();
    836 
    837   if (sys::isLittleEndianHost()) {
    838     // Little-endian host - the source is ordered from LSB to MSB.  Order the
    839     // destination from LSB to MSB: Do a straight copy.
    840     memcpy(Dst, Src, StoreBytes);
    841   } else {
    842     // Big-endian host - the source is an array of 64 bit words ordered from
    843     // LSW to MSW.  Each word is ordered from MSB to LSB.  Order the destination
    844     // from MSB to LSB: Reverse the word order, but not the bytes in a word.
    845     while (StoreBytes > sizeof(uint64_t)) {
    846       StoreBytes -= sizeof(uint64_t);
    847       // May not be aligned so use memcpy.
    848       memcpy(Dst + StoreBytes, Src, sizeof(uint64_t));
    849       Src += sizeof(uint64_t);
    850     }
    851 
    852     memcpy(Dst, Src + sizeof(uint64_t) - StoreBytes, StoreBytes);
    853   }
    854 }
    855 
    856 void ExecutionEngine::StoreValueToMemory(const GenericValue &Val,
    857                                          GenericValue *Ptr, Type *Ty) {
    858   const unsigned StoreBytes = getTargetData()->getTypeStoreSize(Ty);
    859 
    860   switch (Ty->getTypeID()) {
    861   case Type::IntegerTyID:
    862     StoreIntToMemory(Val.IntVal, (uint8_t*)Ptr, StoreBytes);
    863     break;
    864   case Type::FloatTyID:
    865     *((float*)Ptr) = Val.FloatVal;
    866     break;
    867   case Type::DoubleTyID:
    868     *((double*)Ptr) = Val.DoubleVal;
    869     break;
    870   case Type::X86_FP80TyID:
    871     memcpy(Ptr, Val.IntVal.getRawData(), 10);
    872     break;
    873   case Type::PointerTyID:
    874     // Ensure 64 bit target pointers are fully initialized on 32 bit hosts.
    875     if (StoreBytes != sizeof(PointerTy))
    876       memset(&(Ptr->PointerVal), 0, StoreBytes);
    877 
    878     *((PointerTy*)Ptr) = Val.PointerVal;
    879     break;
    880   default:
    881     dbgs() << "Cannot store value of type " << *Ty << "!\n";
    882   }
    883 
    884   if (sys::isLittleEndianHost() != getTargetData()->isLittleEndian())
    885     // Host and target are different endian - reverse the stored bytes.
    886     std::reverse((uint8_t*)Ptr, StoreBytes + (uint8_t*)Ptr);
    887 }
    888 
    889 /// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
    890 /// from Src into IntVal, which is assumed to be wide enough and to hold zero.
    891 static void LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes) {
    892   assert((IntVal.getBitWidth()+7)/8 >= LoadBytes && "Integer too small!");
    893   uint8_t *Dst = (uint8_t *)IntVal.getRawData();
    894 
    895   if (sys::isLittleEndianHost())
    896     // Little-endian host - the destination must be ordered from LSB to MSB.
    897     // The source is ordered from LSB to MSB: Do a straight copy.
    898     memcpy(Dst, Src, LoadBytes);
    899   else {
    900     // Big-endian - the destination is an array of 64 bit words ordered from
    901     // LSW to MSW.  Each word must be ordered from MSB to LSB.  The source is
    902     // ordered from MSB to LSB: Reverse the word order, but not the bytes in
    903     // a word.
    904     while (LoadBytes > sizeof(uint64_t)) {
    905       LoadBytes -= sizeof(uint64_t);
    906       // May not be aligned so use memcpy.
    907       memcpy(Dst, Src + LoadBytes, sizeof(uint64_t));
    908       Dst += sizeof(uint64_t);
    909     }
    910 
    911     memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
    912   }
    913 }
    914 
    915 /// FIXME: document
    916 ///
    917 void ExecutionEngine::LoadValueFromMemory(GenericValue &Result,
    918                                           GenericValue *Ptr,
    919                                           Type *Ty) {
    920   const unsigned LoadBytes = getTargetData()->getTypeStoreSize(Ty);
    921 
    922   switch (Ty->getTypeID()) {
    923   case Type::IntegerTyID:
    924     // An APInt with all words initially zero.
    925     Result.IntVal = APInt(cast<IntegerType>(Ty)->getBitWidth(), 0);
    926     LoadIntFromMemory(Result.IntVal, (uint8_t*)Ptr, LoadBytes);
    927     break;
    928   case Type::FloatTyID:
    929     Result.FloatVal = *((float*)Ptr);
    930     break;
    931   case Type::DoubleTyID:
    932     Result.DoubleVal = *((double*)Ptr);
    933     break;
    934   case Type::PointerTyID:
    935     Result.PointerVal = *((PointerTy*)Ptr);
    936     break;
    937   case Type::X86_FP80TyID: {
    938     // This is endian dependent, but it will only work on x86 anyway.
    939     // FIXME: Will not trap if loading a signaling NaN.
    940     uint64_t y[2];
    941     memcpy(y, Ptr, 10);
    942     Result.IntVal = APInt(80, y);
    943     break;
    944   }
    945   default:
    946     SmallString<256> Msg;
    947     raw_svector_ostream OS(Msg);
    948     OS << "Cannot load value of type " << *Ty << "!";
    949     report_fatal_error(OS.str());
    950   }
    951 }
    952 
    953 void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
    954   DEBUG(dbgs() << "JIT: Initializing " << Addr << " ");
    955   DEBUG(Init->dump());
    956   if (isa<UndefValue>(Init))
    957     return;
    958 
    959   if (const ConstantVector *CP = dyn_cast<ConstantVector>(Init)) {
    960     unsigned ElementSize =
    961       getTargetData()->getTypeAllocSize(CP->getType()->getElementType());
    962     for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
    963       InitializeMemory(CP->getOperand(i), (char*)Addr+i*ElementSize);
    964     return;
    965   }
    966 
    967   if (isa<ConstantAggregateZero>(Init)) {
    968     memset(Addr, 0, (size_t)getTargetData()->getTypeAllocSize(Init->getType()));
    969     return;
    970   }
    971 
    972   if (const ConstantArray *CPA = dyn_cast<ConstantArray>(Init)) {
    973     unsigned ElementSize =
    974       getTargetData()->getTypeAllocSize(CPA->getType()->getElementType());
    975     for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
    976       InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
    977     return;
    978   }
    979 
    980   if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(Init)) {
    981     const StructLayout *SL =
    982       getTargetData()->getStructLayout(cast<StructType>(CPS->getType()));
    983     for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
    984       InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->getElementOffset(i));
    985     return;
    986   }
    987 
    988   if (const ConstantDataSequential *CDS =
    989                dyn_cast<ConstantDataSequential>(Init)) {
    990     // CDS is already laid out in host memory order.
    991     StringRef Data = CDS->getRawDataValues();
    992     memcpy(Addr, Data.data(), Data.size());
    993     return;
    994   }
    995 
    996   if (Init->getType()->isFirstClassType()) {
    997     GenericValue Val = getConstantValue(Init);
    998     StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
    999     return;
   1000   }
   1001 
   1002   DEBUG(dbgs() << "Bad Type: " << *Init->getType() << "\n");
   1003   llvm_unreachable("Unknown constant type to initialize memory with!");
   1004 }
   1005 
   1006 /// EmitGlobals - Emit all of the global variables to memory, storing their
   1007 /// addresses into GlobalAddress.  This must make sure to copy the contents of
   1008 /// their initializers into the memory.
   1009 void ExecutionEngine::emitGlobals() {
   1010   // Loop over all of the global variables in the program, allocating the memory
   1011   // to hold them.  If there is more than one module, do a prepass over globals
   1012   // to figure out how the different modules should link together.
   1013   std::map<std::pair<std::string, Type*>,
   1014            const GlobalValue*> LinkedGlobalsMap;
   1015 
   1016   if (Modules.size() != 1) {
   1017     for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
   1018       Module &M = *Modules[m];
   1019       for (Module::const_global_iterator I = M.global_begin(),
   1020            E = M.global_end(); I != E; ++I) {
   1021         const GlobalValue *GV = I;
   1022         if (GV->hasLocalLinkage() || GV->isDeclaration() ||
   1023             GV->hasAppendingLinkage() || !GV->hasName())
   1024           continue;// Ignore external globals and globals with internal linkage.
   1025 
   1026         const GlobalValue *&GVEntry =
   1027           LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
   1028 
   1029         // If this is the first time we've seen this global, it is the canonical
   1030         // version.
   1031         if (!GVEntry) {
   1032           GVEntry = GV;
   1033           continue;
   1034         }
   1035 
   1036         // If the existing global is strong, never replace it.
   1037         if (GVEntry->hasExternalLinkage() ||
   1038             GVEntry->hasDLLImportLinkage() ||
   1039             GVEntry->hasDLLExportLinkage())
   1040           continue;
   1041 
   1042         // Otherwise, we know it's linkonce/weak, replace it if this is a strong
   1043         // symbol.  FIXME is this right for common?
   1044         if (GV->hasExternalLinkage() || GVEntry->hasExternalWeakLinkage())
   1045           GVEntry = GV;
   1046       }
   1047     }
   1048   }
   1049 
   1050   std::vector<const GlobalValue*> NonCanonicalGlobals;
   1051   for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
   1052     Module &M = *Modules[m];
   1053     for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
   1054          I != E; ++I) {
   1055       // In the multi-module case, see what this global maps to.
   1056       if (!LinkedGlobalsMap.empty()) {
   1057         if (const GlobalValue *GVEntry =
   1058               LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())]) {
   1059           // If something else is the canonical global, ignore this one.
   1060           if (GVEntry != &*I) {
   1061             NonCanonicalGlobals.push_back(I);
   1062             continue;
   1063           }
   1064         }
   1065       }
   1066 
   1067       if (!I->isDeclaration()) {
   1068         addGlobalMapping(I, getMemoryForGV(I));
   1069       } else {
   1070         // External variable reference. Try to use the dynamic loader to
   1071         // get a pointer to it.
   1072         if (void *SymAddr =
   1073             sys::DynamicLibrary::SearchForAddressOfSymbol(I->getName()))
   1074           addGlobalMapping(I, SymAddr);
   1075         else {
   1076           report_fatal_error("Could not resolve external global address: "
   1077                             +I->getName());
   1078         }
   1079       }
   1080     }
   1081 
   1082     // If there are multiple modules, map the non-canonical globals to their
   1083     // canonical location.
   1084     if (!NonCanonicalGlobals.empty()) {
   1085       for (unsigned i = 0, e = NonCanonicalGlobals.size(); i != e; ++i) {
   1086         const GlobalValue *GV = NonCanonicalGlobals[i];
   1087         const GlobalValue *CGV =
   1088           LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
   1089         void *Ptr = getPointerToGlobalIfAvailable(CGV);
   1090         assert(Ptr && "Canonical global wasn't codegen'd!");
   1091         addGlobalMapping(GV, Ptr);
   1092       }
   1093     }
   1094 
   1095     // Now that all of the globals are set up in memory, loop through them all
   1096     // and initialize their contents.
   1097     for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
   1098          I != E; ++I) {
   1099       if (!I->isDeclaration()) {
   1100         if (!LinkedGlobalsMap.empty()) {
   1101           if (const GlobalValue *GVEntry =
   1102                 LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())])
   1103             if (GVEntry != &*I)  // Not the canonical variable.
   1104               continue;
   1105         }
   1106         EmitGlobalVariable(I);
   1107       }
   1108     }
   1109   }
   1110 }
   1111 
   1112 // EmitGlobalVariable - This method emits the specified global variable to the
   1113 // address specified in GlobalAddresses, or allocates new memory if it's not
   1114 // already in the map.
   1115 void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
   1116   void *GA = getPointerToGlobalIfAvailable(GV);
   1117 
   1118   if (GA == 0) {
   1119     // If it's not already specified, allocate memory for the global.
   1120     GA = getMemoryForGV(GV);
   1121     addGlobalMapping(GV, GA);
   1122   }
   1123 
   1124   // Don't initialize if it's thread local, let the client do it.
   1125   if (!GV->isThreadLocal())
   1126     InitializeMemory(GV->getInitializer(), GA);
   1127 
   1128   Type *ElTy = GV->getType()->getElementType();
   1129   size_t GVSize = (size_t)getTargetData()->getTypeAllocSize(ElTy);
   1130   NumInitBytes += (unsigned)GVSize;
   1131   ++NumGlobals;
   1132 }
   1133 
   1134 ExecutionEngineState::ExecutionEngineState(ExecutionEngine &EE)
   1135   : EE(EE), GlobalAddressMap(this) {
   1136 }
   1137 
   1138 sys::Mutex *
   1139 ExecutionEngineState::AddressMapConfig::getMutex(ExecutionEngineState *EES) {
   1140   return &EES->EE.lock;
   1141 }
   1142 
   1143 void ExecutionEngineState::AddressMapConfig::onDelete(ExecutionEngineState *EES,
   1144                                                       const GlobalValue *Old) {
   1145   void *OldVal = EES->GlobalAddressMap.lookup(Old);
   1146   EES->GlobalAddressReverseMap.erase(OldVal);
   1147 }
   1148 
   1149 void ExecutionEngineState::AddressMapConfig::onRAUW(ExecutionEngineState *,
   1150                                                     const GlobalValue *,
   1151                                                     const GlobalValue *) {
   1152   llvm_unreachable("The ExecutionEngine doesn't know how to handle a"
   1153                    " RAUW on a value it has a global mapping for.");
   1154 }
   1155