ExecutionEngine.cpp revision 6456d8639b6f3ede1bb1a90a5d33fe4e719ad4ac 
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/Constants.h"
17#include "llvm/DerivedTypes.h"
18#include "llvm/Module.h"
19#include "llvm/ModuleProvider.h"
20#include "llvm/ADT/Statistic.h"
21#include "llvm/Config/alloca.h"
22#include "llvm/ExecutionEngine/ExecutionEngine.h"
23#include "llvm/ExecutionEngine/GenericValue.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/MutexGuard.h"
26#include "llvm/System/DynamicLibrary.h"
27#include "llvm/System/Host.h"
28#include "llvm/Target/TargetData.h"
29#include <cmath>
30#include <cstring>
31using namespace llvm;
32
33STATISTIC(NumInitBytes, "Number of bytes of global vars initialized");
34STATISTIC(NumGlobals  , "Number of global vars initialized");
35
36ExecutionEngine::EECtorFn ExecutionEngine::JITCtor = 0;
37ExecutionEngine::EECtorFn ExecutionEngine::InterpCtor = 0;
38ExecutionEngine::EERegisterFn ExecutionEngine::ExceptionTableRegister = 0;
39
40
41ExecutionEngine::ExecutionEngine(ModuleProvider *P) : LazyFunctionCreator(0) {
42  LazyCompilationDisabled = false;
43  Modules.push_back(P);
44  assert(P && "ModuleProvider is null?");
45}
46
47ExecutionEngine::~ExecutionEngine() {
48  clearAllGlobalMappings();
49  for (unsigned i = 0, e = Modules.size(); i != e; ++i)
50    delete Modules[i];
51}
52
53/// removeModuleProvider - Remove a ModuleProvider from the list of modules.
54/// Release module from ModuleProvider.
55Module* ExecutionEngine::removeModuleProvider(ModuleProvider *P,
56                                              std::string *ErrInfo) {
57  for(SmallVector<ModuleProvider *, 1>::iterator I = Modules.begin(),
58        E = Modules.end(); I != E; ++I) {
59    ModuleProvider *MP = *I;
60    if (MP == P) {
61      Modules.erase(I);
62      return MP->releaseModule(ErrInfo);
63    }
64  }
65  return NULL;
66}
67
68/// FindFunctionNamed - Search all of the active modules to find the one that
69/// defines FnName.  This is very slow operation and shouldn't be used for
70/// general code.
71Function *ExecutionEngine::FindFunctionNamed(const char *FnName) {
72  for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
73    if (Function *F = Modules[i]->getModule()->getFunction(FnName))
74      return F;
75  }
76  return 0;
77}
78
79
80/// addGlobalMapping - Tell the execution engine that the specified global is
81/// at the specified location.  This is used internally as functions are JIT'd
82/// and as global variables are laid out in memory.  It can and should also be
83/// used by clients of the EE that want to have an LLVM global overlay
84/// existing data in memory.
85void ExecutionEngine::addGlobalMapping(const GlobalValue *GV, void *Addr) {
86  MutexGuard locked(lock);
87
88  void *&CurVal = state.getGlobalAddressMap(locked)[GV];
89  assert((CurVal == 0 || Addr == 0) && "GlobalMapping already established!");
90  CurVal = Addr;
91
92  // If we are using the reverse mapping, add it too
93  if (!state.getGlobalAddressReverseMap(locked).empty()) {
94    const GlobalValue *&V = state.getGlobalAddressReverseMap(locked)[Addr];
95    assert((V == 0 || GV == 0) && "GlobalMapping already established!");
96    V = GV;
97  }
98}
99
100/// clearAllGlobalMappings - Clear all global mappings and start over again
101/// use in dynamic compilation scenarios when you want to move globals
102void ExecutionEngine::clearAllGlobalMappings() {
103  MutexGuard locked(lock);
104
105  state.getGlobalAddressMap(locked).clear();
106  state.getGlobalAddressReverseMap(locked).clear();
107}
108
109/// updateGlobalMapping - Replace an existing mapping for GV with a new
110/// address.  This updates both maps as required.  If "Addr" is null, the
111/// entry for the global is removed from the mappings.
112void ExecutionEngine::updateGlobalMapping(const GlobalValue *GV, void *Addr) {
113  MutexGuard locked(lock);
114
115  // Deleting from the mapping?
116  if (Addr == 0) {
117    state.getGlobalAddressMap(locked).erase(GV);
118    if (!state.getGlobalAddressReverseMap(locked).empty())
119      state.getGlobalAddressReverseMap(locked).erase(Addr);
120    return;
121  }
122
123  void *&CurVal = state.getGlobalAddressMap(locked)[GV];
124  if (CurVal && !state.getGlobalAddressReverseMap(locked).empty())
125    state.getGlobalAddressReverseMap(locked).erase(CurVal);
126  CurVal = Addr;
127
128  // If we are using the reverse mapping, add it too
129  if (!state.getGlobalAddressReverseMap(locked).empty()) {
130    const GlobalValue *&V = state.getGlobalAddressReverseMap(locked)[Addr];
131    assert((V == 0 || GV == 0) && "GlobalMapping already established!");
132    V = GV;
133  }
134}
135
136/// getPointerToGlobalIfAvailable - This returns the address of the specified
137/// global value if it is has already been codegen'd, otherwise it returns null.
138///
139void *ExecutionEngine::getPointerToGlobalIfAvailable(const GlobalValue *GV) {
140  MutexGuard locked(lock);
141
142  std::map<const GlobalValue*, void*>::iterator I =
143  state.getGlobalAddressMap(locked).find(GV);
144  return I != state.getGlobalAddressMap(locked).end() ? I->second : 0;
145}
146
147/// getGlobalValueAtAddress - Return the LLVM global value object that starts
148/// at the specified address.
149///
150const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
151  MutexGuard locked(lock);
152
153  // If we haven't computed the reverse mapping yet, do so first.
154  if (state.getGlobalAddressReverseMap(locked).empty()) {
155    for (std::map<const GlobalValue*, void *>::iterator
156         I = state.getGlobalAddressMap(locked).begin(),
157         E = state.getGlobalAddressMap(locked).end(); I != E; ++I)
158      state.getGlobalAddressReverseMap(locked).insert(std::make_pair(I->second,
159                                                                     I->first));
160  }
161
162  std::map<void *, const GlobalValue*>::iterator I =
163    state.getGlobalAddressReverseMap(locked).find(Addr);
164  return I != state.getGlobalAddressReverseMap(locked).end() ? I->second : 0;
165}
166
167// CreateArgv - Turn a vector of strings into a nice argv style array of
168// pointers to null terminated strings.
169//
170static void *CreateArgv(ExecutionEngine *EE,
171                        const std::vector<std::string> &InputArgv) {
172  unsigned PtrSize = EE->getTargetData()->getPointerSize();
173  char *Result = new char[(InputArgv.size()+1)*PtrSize];
174
175  DOUT << "ARGV = " << (void*)Result << "\n";
176  const Type *SBytePtr = PointerType::getUnqual(Type::Int8Ty);
177
178  for (unsigned i = 0; i != InputArgv.size(); ++i) {
179    unsigned Size = InputArgv[i].size()+1;
180    char *Dest = new char[Size];
181    DOUT << "ARGV[" << i << "] = " << (void*)Dest << "\n";
182
183    std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest);
184    Dest[Size-1] = 0;
185
186    // Endian safe: Result[i] = (PointerTy)Dest;
187    EE->StoreValueToMemory(PTOGV(Dest), (GenericValue*)(Result+i*PtrSize),
188                           SBytePtr);
189  }
190
191  // Null terminate it
192  EE->StoreValueToMemory(PTOGV(0),
193                         (GenericValue*)(Result+InputArgv.size()*PtrSize),
194                         SBytePtr);
195  return Result;
196}
197
198
199/// runStaticConstructorsDestructors - This method is used to execute all of
200/// the static constructors or destructors for a program, depending on the
201/// value of isDtors.
202void ExecutionEngine::runStaticConstructorsDestructors(bool isDtors) {
203  const char *Name = isDtors ? "llvm.global_dtors" : "llvm.global_ctors";
204
205  // Execute global ctors/dtors for each module in the program.
206  for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
207    GlobalVariable *GV = Modules[m]->getModule()->getNamedGlobal(Name);
208
209    // If this global has internal linkage, or if it has a use, then it must be
210    // an old-style (llvmgcc3) static ctor with __main linked in and in use.  If
211    // this is the case, don't execute any of the global ctors, __main will do
212    // it.
213    if (!GV || GV->isDeclaration() || GV->hasInternalLinkage()) continue;
214
215    // Should be an array of '{ int, void ()* }' structs.  The first value is
216    // the init priority, which we ignore.
217    ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
218    if (!InitList) continue;
219    for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
220      if (ConstantStruct *CS =
221          dyn_cast<ConstantStruct>(InitList->getOperand(i))) {
222        if (CS->getNumOperands() != 2) break; // Not array of 2-element structs.
223
224        Constant *FP = CS->getOperand(1);
225        if (FP->isNullValue())
226          break;  // Found a null terminator, exit.
227
228        if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
229          if (CE->isCast())
230            FP = CE->getOperand(0);
231        if (Function *F = dyn_cast<Function>(FP)) {
232          // Execute the ctor/dtor function!
233          runFunction(F, std::vector<GenericValue>());
234        }
235      }
236  }
237}
238
239/// isTargetNullPtr - Return whether the target pointer stored at Loc is null.
240static bool isTargetNullPtr(ExecutionEngine *EE, void *Loc) {
241  unsigned PtrSize = EE->getTargetData()->getPointerSize();
242  for (unsigned i = 0; i < PtrSize; ++i)
243    if (*(i + (uint8_t*)Loc))
244      return false;
245  return true;
246}
247
248/// runFunctionAsMain - This is a helper function which wraps runFunction to
249/// handle the common task of starting up main with the specified argc, argv,
250/// and envp parameters.
251int ExecutionEngine::runFunctionAsMain(Function *Fn,
252                                       const std::vector<std::string> &argv,
253                                       const char * const * envp) {
254  std::vector<GenericValue> GVArgs;
255  GenericValue GVArgc;
256  GVArgc.IntVal = APInt(32, argv.size());
257
258  // Check main() type
259  unsigned NumArgs = Fn->getFunctionType()->getNumParams();
260  const FunctionType *FTy = Fn->getFunctionType();
261  const Type* PPInt8Ty =
262    PointerType::getUnqual(PointerType::getUnqual(Type::Int8Ty));
263  switch (NumArgs) {
264  case 3:
265   if (FTy->getParamType(2) != PPInt8Ty) {
266     cerr << "Invalid type for third argument of main() supplied\n";
267     abort();
268   }
269   // FALLS THROUGH
270  case 2:
271   if (FTy->getParamType(1) != PPInt8Ty) {
272     cerr << "Invalid type for second argument of main() supplied\n";
273     abort();
274   }
275   // FALLS THROUGH
276  case 1:
277   if (FTy->getParamType(0) != Type::Int32Ty) {
278     cerr << "Invalid type for first argument of main() supplied\n";
279     abort();
280   }
281   // FALLS THROUGH
282  case 0:
283   if (FTy->getReturnType() != Type::Int32Ty &&
284       FTy->getReturnType() != Type::VoidTy) {
285     cerr << "Invalid return type of main() supplied\n";
286     abort();
287   }
288   break;
289  default:
290   cerr << "Invalid number of arguments of main() supplied\n";
291   abort();
292  }
293
294  if (NumArgs) {
295    GVArgs.push_back(GVArgc); // Arg #0 = argc.
296    if (NumArgs > 1) {
297      GVArgs.push_back(PTOGV(CreateArgv(this, argv))); // Arg #1 = argv.
298      assert(!isTargetNullPtr(this, GVTOP(GVArgs[1])) &&
299             "argv[0] was null after CreateArgv");
300      if (NumArgs > 2) {
301        std::vector<std::string> EnvVars;
302        for (unsigned i = 0; envp[i]; ++i)
303          EnvVars.push_back(envp[i]);
304        GVArgs.push_back(PTOGV(CreateArgv(this, EnvVars))); // Arg #2 = envp.
305      }
306    }
307  }
308  return runFunction(Fn, GVArgs).IntVal.getZExtValue();
309}
310
311/// If possible, create a JIT, unless the caller specifically requests an
312/// Interpreter or there's an error. If even an Interpreter cannot be created,
313/// NULL is returned.
314///
315ExecutionEngine *ExecutionEngine::create(ModuleProvider *MP,
316                                         bool ForceInterpreter,
317                                         std::string *ErrorStr) {
318  ExecutionEngine *EE = 0;
319
320  // Make sure we can resolve symbols in the program as well. The zero arg
321  // to the function tells DynamicLibrary to load the program, not a library.
322  if (sys::DynamicLibrary::LoadLibraryPermanently(0, ErrorStr))
323    return 0;
324
325  // Unless the interpreter was explicitly selected, try making a JIT.
326  if (!ForceInterpreter && JITCtor)
327    EE = JITCtor(MP, ErrorStr);
328
329  // If we can't make a JIT, make an interpreter instead.
330  if (EE == 0 && InterpCtor)
331    EE = InterpCtor(MP, ErrorStr);
332
333  return EE;
334}
335
336ExecutionEngine *ExecutionEngine::create(Module *M) {
337  return create(new ExistingModuleProvider(M));
338}
339
340/// getPointerToGlobal - This returns the address of the specified global
341/// value.  This may involve code generation if it's a function.
342///
343void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
344  if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
345    return getPointerToFunction(F);
346
347  MutexGuard locked(lock);
348  void *p = state.getGlobalAddressMap(locked)[GV];
349  if (p)
350    return p;
351
352  // Global variable might have been added since interpreter started.
353  if (GlobalVariable *GVar =
354          const_cast<GlobalVariable *>(dyn_cast<GlobalVariable>(GV)))
355    EmitGlobalVariable(GVar);
356  else
357    assert(0 && "Global hasn't had an address allocated yet!");
358  return state.getGlobalAddressMap(locked)[GV];
359}
360
361/// This function converts a Constant* into a GenericValue. The interesting
362/// part is if C is a ConstantExpr.
363/// @brief Get a GenericValue for a Constant*
364GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
365  // If its undefined, return the garbage.
366  if (isa<UndefValue>(C))
367    return GenericValue();
368
369  // If the value is a ConstantExpr
370  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
371    Constant *Op0 = CE->getOperand(0);
372    switch (CE->getOpcode()) {
373    case Instruction::GetElementPtr: {
374      // Compute the index
375      GenericValue Result = getConstantValue(Op0);
376      SmallVector<Value*, 8> Indices(CE->op_begin()+1, CE->op_end());
377      uint64_t Offset =
378        TD->getIndexedOffset(Op0->getType(), &Indices[0], Indices.size());
379
380      char* tmp = (char*) Result.PointerVal;
381      Result = PTOGV(tmp + Offset);
382      return Result;
383    }
384    case Instruction::Trunc: {
385      GenericValue GV = getConstantValue(Op0);
386      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
387      GV.IntVal = GV.IntVal.trunc(BitWidth);
388      return GV;
389    }
390    case Instruction::ZExt: {
391      GenericValue GV = getConstantValue(Op0);
392      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
393      GV.IntVal = GV.IntVal.zext(BitWidth);
394      return GV;
395    }
396    case Instruction::SExt: {
397      GenericValue GV = getConstantValue(Op0);
398      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
399      GV.IntVal = GV.IntVal.sext(BitWidth);
400      return GV;
401    }
402    case Instruction::FPTrunc: {
403      // FIXME long double
404      GenericValue GV = getConstantValue(Op0);
405      GV.FloatVal = float(GV.DoubleVal);
406      return GV;
407    }
408    case Instruction::FPExt:{
409      // FIXME long double
410      GenericValue GV = getConstantValue(Op0);
411      GV.DoubleVal = double(GV.FloatVal);
412      return GV;
413    }
414    case Instruction::UIToFP: {
415      GenericValue GV = getConstantValue(Op0);
416      if (CE->getType() == Type::FloatTy)
417        GV.FloatVal = float(GV.IntVal.roundToDouble());
418      else if (CE->getType() == Type::DoubleTy)
419        GV.DoubleVal = GV.IntVal.roundToDouble();
420      else if (CE->getType() == Type::X86_FP80Ty) {
421        const uint64_t zero[] = {0, 0};
422        APFloat apf = APFloat(APInt(80, 2, zero));
423        (void)apf.convertFromAPInt(GV.IntVal,
424                                   false,
425                                   APFloat::rmNearestTiesToEven);
426        GV.IntVal = apf.convertToAPInt();
427      }
428      return GV;
429    }
430    case Instruction::SIToFP: {
431      GenericValue GV = getConstantValue(Op0);
432      if (CE->getType() == Type::FloatTy)
433        GV.FloatVal = float(GV.IntVal.signedRoundToDouble());
434      else if (CE->getType() == Type::DoubleTy)
435        GV.DoubleVal = GV.IntVal.signedRoundToDouble();
436      else if (CE->getType() == Type::X86_FP80Ty) {
437        const uint64_t zero[] = { 0, 0};
438        APFloat apf = APFloat(APInt(80, 2, zero));
439        (void)apf.convertFromAPInt(GV.IntVal,
440                                   true,
441                                   APFloat::rmNearestTiesToEven);
442        GV.IntVal = apf.convertToAPInt();
443      }
444      return GV;
445    }
446    case Instruction::FPToUI: // double->APInt conversion handles sign
447    case Instruction::FPToSI: {
448      GenericValue GV = getConstantValue(Op0);
449      uint32_t BitWidth = cast<IntegerType>(CE->getType())->getBitWidth();
450      if (Op0->getType() == Type::FloatTy)
451        GV.IntVal = APIntOps::RoundFloatToAPInt(GV.FloatVal, BitWidth);
452      else if (Op0->getType() == Type::DoubleTy)
453        GV.IntVal = APIntOps::RoundDoubleToAPInt(GV.DoubleVal, BitWidth);
454      else if (Op0->getType() == Type::X86_FP80Ty) {
455        APFloat apf = APFloat(GV.IntVal);
456        uint64_t v;
457        (void)apf.convertToInteger(&v, BitWidth,
458                                   CE->getOpcode()==Instruction::FPToSI,
459                                   APFloat::rmTowardZero);
460        GV.IntVal = v; // endian?
461      }
462      return GV;
463    }
464    case Instruction::PtrToInt: {
465      GenericValue GV = getConstantValue(Op0);
466      uint32_t PtrWidth = TD->getPointerSizeInBits();
467      GV.IntVal = APInt(PtrWidth, uintptr_t(GV.PointerVal));
468      return GV;
469    }
470    case Instruction::IntToPtr: {
471      GenericValue GV = getConstantValue(Op0);
472      uint32_t PtrWidth = TD->getPointerSizeInBits();
473      if (PtrWidth != GV.IntVal.getBitWidth())
474        GV.IntVal = GV.IntVal.zextOrTrunc(PtrWidth);
475      assert(GV.IntVal.getBitWidth() <= 64 && "Bad pointer width");
476      GV.PointerVal = PointerTy(uintptr_t(GV.IntVal.getZExtValue()));
477      return GV;
478    }
479    case Instruction::BitCast: {
480      GenericValue GV = getConstantValue(Op0);
481      const Type* DestTy = CE->getType();
482      switch (Op0->getType()->getTypeID()) {
483        default: assert(0 && "Invalid bitcast operand");
484        case Type::IntegerTyID:
485          assert(DestTy->isFloatingPoint() && "invalid bitcast");
486          if (DestTy == Type::FloatTy)
487            GV.FloatVal = GV.IntVal.bitsToFloat();
488          else if (DestTy == Type::DoubleTy)
489            GV.DoubleVal = GV.IntVal.bitsToDouble();
490          break;
491        case Type::FloatTyID:
492          assert(DestTy == Type::Int32Ty && "Invalid bitcast");
493          GV.IntVal.floatToBits(GV.FloatVal);
494          break;
495        case Type::DoubleTyID:
496          assert(DestTy == Type::Int64Ty && "Invalid bitcast");
497          GV.IntVal.doubleToBits(GV.DoubleVal);
498          break;
499        case Type::PointerTyID:
500          assert(isa<PointerType>(DestTy) && "Invalid bitcast");
501          break; // getConstantValue(Op0)  above already converted it
502      }
503      return GV;
504    }
505    case Instruction::Add:
506    case Instruction::Sub:
507    case Instruction::Mul:
508    case Instruction::UDiv:
509    case Instruction::SDiv:
510    case Instruction::URem:
511    case Instruction::SRem:
512    case Instruction::And:
513    case Instruction::Or:
514    case Instruction::Xor: {
515      GenericValue LHS = getConstantValue(Op0);
516      GenericValue RHS = getConstantValue(CE->getOperand(1));
517      GenericValue GV;
518      switch (CE->getOperand(0)->getType()->getTypeID()) {
519      default: assert(0 && "Bad add type!"); abort();
520      case Type::IntegerTyID:
521        switch (CE->getOpcode()) {
522          default: assert(0 && "Invalid integer opcode");
523          case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
524          case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
525          case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
526          case Instruction::UDiv:GV.IntVal = LHS.IntVal.udiv(RHS.IntVal); break;
527          case Instruction::SDiv:GV.IntVal = LHS.IntVal.sdiv(RHS.IntVal); break;
528          case Instruction::URem:GV.IntVal = LHS.IntVal.urem(RHS.IntVal); break;
529          case Instruction::SRem:GV.IntVal = LHS.IntVal.srem(RHS.IntVal); break;
530          case Instruction::And: GV.IntVal = LHS.IntVal & RHS.IntVal; break;
531          case Instruction::Or:  GV.IntVal = LHS.IntVal | RHS.IntVal; break;
532          case Instruction::Xor: GV.IntVal = LHS.IntVal ^ RHS.IntVal; break;
533        }
534        break;
535      case Type::FloatTyID:
536        switch (CE->getOpcode()) {
537          default: assert(0 && "Invalid float opcode"); abort();
538          case Instruction::Add:
539            GV.FloatVal = LHS.FloatVal + RHS.FloatVal; break;
540          case Instruction::Sub:
541            GV.FloatVal = LHS.FloatVal - RHS.FloatVal; break;
542          case Instruction::Mul:
543            GV.FloatVal = LHS.FloatVal * RHS.FloatVal; break;
544          case Instruction::FDiv:
545            GV.FloatVal = LHS.FloatVal / RHS.FloatVal; break;
546          case Instruction::FRem:
547            GV.FloatVal = ::fmodf(LHS.FloatVal,RHS.FloatVal); break;
548        }
549        break;
550      case Type::DoubleTyID:
551        switch (CE->getOpcode()) {
552          default: assert(0 && "Invalid double opcode"); abort();
553          case Instruction::Add:
554            GV.DoubleVal = LHS.DoubleVal + RHS.DoubleVal; break;
555          case Instruction::Sub:
556            GV.DoubleVal = LHS.DoubleVal - RHS.DoubleVal; break;
557          case Instruction::Mul:
558            GV.DoubleVal = LHS.DoubleVal * RHS.DoubleVal; break;
559          case Instruction::FDiv:
560            GV.DoubleVal = LHS.DoubleVal / RHS.DoubleVal; break;
561          case Instruction::FRem:
562            GV.DoubleVal = ::fmod(LHS.DoubleVal,RHS.DoubleVal); break;
563        }
564        break;
565      case Type::X86_FP80TyID:
566      case Type::PPC_FP128TyID:
567      case Type::FP128TyID: {
568        APFloat apfLHS = APFloat(LHS.IntVal);
569        switch (CE->getOpcode()) {
570          default: assert(0 && "Invalid long double opcode"); abort();
571          case Instruction::Add:
572            apfLHS.add(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
573            GV.IntVal = apfLHS.convertToAPInt();
574            break;
575          case Instruction::Sub:
576            apfLHS.subtract(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
577            GV.IntVal = apfLHS.convertToAPInt();
578            break;
579          case Instruction::Mul:
580            apfLHS.multiply(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
581            GV.IntVal = apfLHS.convertToAPInt();
582            break;
583          case Instruction::FDiv:
584            apfLHS.divide(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
585            GV.IntVal = apfLHS.convertToAPInt();
586            break;
587          case Instruction::FRem:
588            apfLHS.mod(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
589            GV.IntVal = apfLHS.convertToAPInt();
590            break;
591          }
592        }
593        break;
594      }
595      return GV;
596    }
597    default:
598      break;
599    }
600    cerr << "ConstantExpr not handled: " << *CE << "\n";
601    abort();
602  }
603
604  GenericValue Result;
605  switch (C->getType()->getTypeID()) {
606  case Type::FloatTyID:
607    Result.FloatVal = cast<ConstantFP>(C)->getValueAPF().convertToFloat();
608    break;
609  case Type::DoubleTyID:
610    Result.DoubleVal = cast<ConstantFP>(C)->getValueAPF().convertToDouble();
611    break;
612  case Type::X86_FP80TyID:
613  case Type::FP128TyID:
614  case Type::PPC_FP128TyID:
615    Result.IntVal = cast <ConstantFP>(C)->getValueAPF().convertToAPInt();
616    break;
617  case Type::IntegerTyID:
618    Result.IntVal = cast<ConstantInt>(C)->getValue();
619    break;
620  case Type::PointerTyID:
621    if (isa<ConstantPointerNull>(C))
622      Result.PointerVal = 0;
623    else if (const Function *F = dyn_cast<Function>(C))
624      Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
625    else if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
626      Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
627    else
628      assert(0 && "Unknown constant pointer type!");
629    break;
630  default:
631    cerr << "ERROR: Constant unimplemented for type: " << *C->getType() << "\n";
632    abort();
633  }
634  return Result;
635}
636
637/// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
638/// with the integer held in IntVal.
639static void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
640                             unsigned StoreBytes) {
641  assert((IntVal.getBitWidth()+7)/8 >= StoreBytes && "Integer too small!");
642  uint8_t *Src = (uint8_t *)IntVal.getRawData();
643
644  if (sys::littleEndianHost())
645    // Little-endian host - the source is ordered from LSB to MSB.  Order the
646    // destination from LSB to MSB: Do a straight copy.
647    memcpy(Dst, Src, StoreBytes);
648  else {
649    // Big-endian host - the source is an array of 64 bit words ordered from
650    // LSW to MSW.  Each word is ordered from MSB to LSB.  Order the destination
651    // from MSB to LSB: Reverse the word order, but not the bytes in a word.
652    while (StoreBytes > sizeof(uint64_t)) {
653      StoreBytes -= sizeof(uint64_t);
654      // May not be aligned so use memcpy.
655      memcpy(Dst + StoreBytes, Src, sizeof(uint64_t));
656      Src += sizeof(uint64_t);
657    }
658
659    memcpy(Dst, Src + sizeof(uint64_t) - StoreBytes, StoreBytes);
660  }
661}
662
663/// StoreValueToMemory - Stores the data in Val of type Ty at address Ptr.  Ptr
664/// is the address of the memory at which to store Val, cast to GenericValue *.
665/// It is not a pointer to a GenericValue containing the address at which to
666/// store Val.
667void ExecutionEngine::StoreValueToMemory(const GenericValue &Val, GenericValue *Ptr,
668                                         const Type *Ty) {
669  const unsigned StoreBytes = getTargetData()->getTypeStoreSize(Ty);
670
671  switch (Ty->getTypeID()) {
672  case Type::IntegerTyID:
673    StoreIntToMemory(Val.IntVal, (uint8_t*)Ptr, StoreBytes);
674    break;
675  case Type::FloatTyID:
676    *((float*)Ptr) = Val.FloatVal;
677    break;
678  case Type::DoubleTyID:
679    *((double*)Ptr) = Val.DoubleVal;
680    break;
681  case Type::X86_FP80TyID: {
682      uint16_t *Dest = (uint16_t*)Ptr;
683      const uint16_t *Src = (uint16_t*)Val.IntVal.getRawData();
684      // This is endian dependent, but it will only work on x86 anyway.
685      Dest[0] = Src[4];
686      Dest[1] = Src[0];
687      Dest[2] = Src[1];
688      Dest[3] = Src[2];
689      Dest[4] = Src[3];
690      break;
691    }
692  case Type::PointerTyID:
693    // Ensure 64 bit target pointers are fully initialized on 32 bit hosts.
694    if (StoreBytes != sizeof(PointerTy))
695      memset(Ptr, 0, StoreBytes);
696
697    *((PointerTy*)Ptr) = Val.PointerVal;
698    break;
699  default:
700    cerr << "Cannot store value of type " << *Ty << "!\n";
701  }
702
703  if (sys::littleEndianHost() != getTargetData()->isLittleEndian())
704    // Host and target are different endian - reverse the stored bytes.
705    std::reverse((uint8_t*)Ptr, StoreBytes + (uint8_t*)Ptr);
706}
707
708/// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
709/// from Src into IntVal, which is assumed to be wide enough and to hold zero.
710static void LoadIntFromMemory(APInt &IntVal, uint8_t *Src, unsigned LoadBytes) {
711  assert((IntVal.getBitWidth()+7)/8 >= LoadBytes && "Integer too small!");
712  uint8_t *Dst = (uint8_t *)IntVal.getRawData();
713
714  if (sys::littleEndianHost())
715    // Little-endian host - the destination must be ordered from LSB to MSB.
716    // The source is ordered from LSB to MSB: Do a straight copy.
717    memcpy(Dst, Src, LoadBytes);
718  else {
719    // Big-endian - the destination is an array of 64 bit words ordered from
720    // LSW to MSW.  Each word must be ordered from MSB to LSB.  The source is
721    // ordered from MSB to LSB: Reverse the word order, but not the bytes in
722    // a word.
723    while (LoadBytes > sizeof(uint64_t)) {
724      LoadBytes -= sizeof(uint64_t);
725      // May not be aligned so use memcpy.
726      memcpy(Dst, Src + LoadBytes, sizeof(uint64_t));
727      Dst += sizeof(uint64_t);
728    }
729
730    memcpy(Dst + sizeof(uint64_t) - LoadBytes, Src, LoadBytes);
731  }
732}
733
734/// FIXME: document
735///
736void ExecutionEngine::LoadValueFromMemory(GenericValue &Result,
737                                                  GenericValue *Ptr,
738                                                  const Type *Ty) {
739  const unsigned LoadBytes = getTargetData()->getTypeStoreSize(Ty);
740
741  if (sys::littleEndianHost() != getTargetData()->isLittleEndian()) {
742    // Host and target are different endian - reverse copy the stored
743    // bytes into a buffer, and load from that.
744    uint8_t *Src = (uint8_t*)Ptr;
745    uint8_t *Buf = (uint8_t*)alloca(LoadBytes);
746    std::reverse_copy(Src, Src + LoadBytes, Buf);
747    Ptr = (GenericValue*)Buf;
748  }
749
750  switch (Ty->getTypeID()) {
751  case Type::IntegerTyID:
752    // An APInt with all words initially zero.
753    Result.IntVal = APInt(cast<IntegerType>(Ty)->getBitWidth(), 0);
754    LoadIntFromMemory(Result.IntVal, (uint8_t*)Ptr, LoadBytes);
755    break;
756  case Type::FloatTyID:
757    Result.FloatVal = *((float*)Ptr);
758    break;
759  case Type::DoubleTyID:
760    Result.DoubleVal = *((double*)Ptr);
761    break;
762  case Type::PointerTyID:
763    Result.PointerVal = *((PointerTy*)Ptr);
764    break;
765  case Type::X86_FP80TyID: {
766    // This is endian dependent, but it will only work on x86 anyway.
767    // FIXME: Will not trap if loading a signaling NaN.
768    uint16_t *p = (uint16_t*)Ptr;
769    union {
770      uint16_t x[8];
771      uint64_t y[2];
772    };
773    x[0] = p[1];
774    x[1] = p[2];
775    x[2] = p[3];
776    x[3] = p[4];
777    x[4] = p[0];
778    Result.IntVal = APInt(80, 2, y);
779    break;
780  }
781  default:
782    cerr << "Cannot load value of type " << *Ty << "!\n";
783    abort();
784  }
785}
786
787// InitializeMemory - Recursive function to apply a Constant value into the
788// specified memory location...
789//
790void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
791  if (isa<UndefValue>(Init)) {
792    return;
793  } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(Init)) {
794    unsigned ElementSize =
795      getTargetData()->getABITypeSize(CP->getType()->getElementType());
796    for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
797      InitializeMemory(CP->getOperand(i), (char*)Addr+i*ElementSize);
798    return;
799  } else if (isa<ConstantAggregateZero>(Init)) {
800    memset(Addr, 0, (size_t)getTargetData()->getABITypeSize(Init->getType()));
801    return;
802  } else if (Init->getType()->isFirstClassType()) {
803    GenericValue Val = getConstantValue(Init);
804    StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
805    return;
806  }
807
808  switch (Init->getType()->getTypeID()) {
809  case Type::ArrayTyID: {
810    const ConstantArray *CPA = cast<ConstantArray>(Init);
811    unsigned ElementSize =
812      getTargetData()->getABITypeSize(CPA->getType()->getElementType());
813    for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
814      InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
815    return;
816  }
817
818  case Type::StructTyID: {
819    const ConstantStruct *CPS = cast<ConstantStruct>(Init);
820    const StructLayout *SL =
821      getTargetData()->getStructLayout(cast<StructType>(CPS->getType()));
822    for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
823      InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->getElementOffset(i));
824    return;
825  }
826
827  default:
828    cerr << "Bad Type: " << *Init->getType() << "\n";
829    assert(0 && "Unknown constant type to initialize memory with!");
830  }
831}
832
833/// EmitGlobals - Emit all of the global variables to memory, storing their
834/// addresses into GlobalAddress.  This must make sure to copy the contents of
835/// their initializers into the memory.
836///
837void ExecutionEngine::emitGlobals() {
838  const TargetData *TD = getTargetData();
839
840  // Loop over all of the global variables in the program, allocating the memory
841  // to hold them.  If there is more than one module, do a prepass over globals
842  // to figure out how the different modules should link together.
843  //
844  std::map<std::pair<std::string, const Type*>,
845           const GlobalValue*> LinkedGlobalsMap;
846
847  if (Modules.size() != 1) {
848    for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
849      Module &M = *Modules[m]->getModule();
850      for (Module::const_global_iterator I = M.global_begin(),
851           E = M.global_end(); I != E; ++I) {
852        const GlobalValue *GV = I;
853        if (GV->hasInternalLinkage() || GV->isDeclaration() ||
854            GV->hasAppendingLinkage() || !GV->hasName())
855          continue;// Ignore external globals and globals with internal linkage.
856
857        const GlobalValue *&GVEntry =
858          LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
859
860        // If this is the first time we've seen this global, it is the canonical
861        // version.
862        if (!GVEntry) {
863          GVEntry = GV;
864          continue;
865        }
866
867        // If the existing global is strong, never replace it.
868        if (GVEntry->hasExternalLinkage() ||
869            GVEntry->hasDLLImportLinkage() ||
870            GVEntry->hasDLLExportLinkage())
871          continue;
872
873        // Otherwise, we know it's linkonce/weak, replace it if this is a strong
874        // symbol.
875        if (GV->hasExternalLinkage() || GVEntry->hasExternalWeakLinkage())
876          GVEntry = GV;
877      }
878    }
879  }
880
881  std::vector<const GlobalValue*> NonCanonicalGlobals;
882  for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
883    Module &M = *Modules[m]->getModule();
884    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
885         I != E; ++I) {
886      // In the multi-module case, see what this global maps to.
887      if (!LinkedGlobalsMap.empty()) {
888        if (const GlobalValue *GVEntry =
889              LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())]) {
890          // If something else is the canonical global, ignore this one.
891          if (GVEntry != &*I) {
892            NonCanonicalGlobals.push_back(I);
893            continue;
894          }
895        }
896      }
897
898      if (!I->isDeclaration()) {
899        // Get the type of the global.
900        const Type *Ty = I->getType()->getElementType();
901
902        // Allocate some memory for it!
903        unsigned Size = TD->getABITypeSize(Ty);
904        addGlobalMapping(I, new char[Size]);
905      } else {
906        // External variable reference. Try to use the dynamic loader to
907        // get a pointer to it.
908        if (void *SymAddr =
909            sys::DynamicLibrary::SearchForAddressOfSymbol(I->getName().c_str()))
910          addGlobalMapping(I, SymAddr);
911        else {
912          cerr << "Could not resolve external global address: "
913               << I->getName() << "\n";
914          abort();
915        }
916      }
917    }
918
919    // If there are multiple modules, map the non-canonical globals to their
920    // canonical location.
921    if (!NonCanonicalGlobals.empty()) {
922      for (unsigned i = 0, e = NonCanonicalGlobals.size(); i != e; ++i) {
923        const GlobalValue *GV = NonCanonicalGlobals[i];
924        const GlobalValue *CGV =
925          LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
926        void *Ptr = getPointerToGlobalIfAvailable(CGV);
927        assert(Ptr && "Canonical global wasn't codegen'd!");
928        addGlobalMapping(GV, getPointerToGlobalIfAvailable(CGV));
929      }
930    }
931
932    // Now that all of the globals are set up in memory, loop through them all
933    // and initialize their contents.
934    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
935         I != E; ++I) {
936      if (!I->isDeclaration()) {
937        if (!LinkedGlobalsMap.empty()) {
938          if (const GlobalValue *GVEntry =
939                LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())])
940            if (GVEntry != &*I)  // Not the canonical variable.
941              continue;
942        }
943        EmitGlobalVariable(I);
944      }
945    }
946  }
947}
948
949// EmitGlobalVariable - This method emits the specified global variable to the
950// address specified in GlobalAddresses, or allocates new memory if it's not
951// already in the map.
952void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
953  void *GA = getPointerToGlobalIfAvailable(GV);
954  DOUT << "Global '" << GV->getName() << "' -> " << GA << "\n";
955
956  const Type *ElTy = GV->getType()->getElementType();
957  size_t GVSize = (size_t)getTargetData()->getABITypeSize(ElTy);
958  if (GA == 0) {
959    // If it's not already specified, allocate memory for the global.
960    GA = new char[GVSize];
961    addGlobalMapping(GV, GA);
962  }
963
964  InitializeMemory(GV->getInitializer(), GA);
965  NumInitBytes += (unsigned)GVSize;
966  ++NumGlobals;
967}
968