ExecutionEngine.cpp revision 551ccae044b0ff658fe629dd67edd5ffe75d10e8 
1//===-- ExecutionEngine.cpp - Common Implementation shared by EEs ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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 "Interpreter/Interpreter.h"
17#include "JIT/JIT.h"
18#include "llvm/Constants.h"
19#include "llvm/DerivedTypes.h"
20#include "llvm/Module.h"
21#include "llvm/ModuleProvider.h"
22#include "llvm/CodeGen/IntrinsicLowering.h"
23#include "llvm/ExecutionEngine/ExecutionEngine.h"
24#include "llvm/ExecutionEngine/GenericValue.h"
25#include "llvm/Target/TargetData.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/ADT/Statistic.h"
28#include "llvm/Support/DynamicLinker.h"
29using namespace llvm;
30
31namespace {
32  Statistic<> NumInitBytes("lli", "Number of bytes of global vars initialized");
33  Statistic<> NumGlobals  ("lli", "Number of global vars initialized");
34}
35
36ExecutionEngine::ExecutionEngine(ModuleProvider *P) :
37  CurMod(*P->getModule()), MP(P) {
38  assert(P && "ModuleProvider is null?");
39}
40
41ExecutionEngine::ExecutionEngine(Module *M) : CurMod(*M), MP(0) {
42  assert(M && "Module is null?");
43}
44
45ExecutionEngine::~ExecutionEngine() {
46  delete MP;
47}
48
49/// getGlobalValueAtAddress - Return the LLVM global value object that starts
50/// at the specified address.
51///
52const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
53  // If we haven't computed the reverse mapping yet, do so first.
54  if (GlobalAddressReverseMap.empty()) {
55    for (std::map<const GlobalValue*, void *>::iterator I =
56           GlobalAddressMap.begin(), E = GlobalAddressMap.end(); I != E; ++I)
57      GlobalAddressReverseMap.insert(std::make_pair(I->second, I->first));
58  }
59
60  std::map<void *, const GlobalValue*>::iterator I =
61    GlobalAddressReverseMap.find(Addr);
62  return I != GlobalAddressReverseMap.end() ? I->second : 0;
63}
64
65// CreateArgv - Turn a vector of strings into a nice argv style array of
66// pointers to null terminated strings.
67//
68static void *CreateArgv(ExecutionEngine *EE,
69                        const std::vector<std::string> &InputArgv) {
70  unsigned PtrSize = EE->getTargetData().getPointerSize();
71  char *Result = new char[(InputArgv.size()+1)*PtrSize];
72
73  DEBUG(std::cerr << "ARGV = " << (void*)Result << "\n");
74  const Type *SBytePtr = PointerType::get(Type::SByteTy);
75
76  for (unsigned i = 0; i != InputArgv.size(); ++i) {
77    unsigned Size = InputArgv[i].size()+1;
78    char *Dest = new char[Size];
79    DEBUG(std::cerr << "ARGV[" << i << "] = " << (void*)Dest << "\n");
80
81    std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest);
82    Dest[Size-1] = 0;
83
84    // Endian safe: Result[i] = (PointerTy)Dest;
85    EE->StoreValueToMemory(PTOGV(Dest), (GenericValue*)(Result+i*PtrSize),
86                           SBytePtr);
87  }
88
89  // Null terminate it
90  EE->StoreValueToMemory(PTOGV(0),
91                         (GenericValue*)(Result+InputArgv.size()*PtrSize),
92                         SBytePtr);
93  return Result;
94}
95
96/// runFunctionAsMain - This is a helper function which wraps runFunction to
97/// handle the common task of starting up main with the specified argc, argv,
98/// and envp parameters.
99int ExecutionEngine::runFunctionAsMain(Function *Fn,
100                                       const std::vector<std::string> &argv,
101                                       const char * const * envp) {
102  std::vector<GenericValue> GVArgs;
103  GenericValue GVArgc;
104  GVArgc.IntVal = argv.size();
105  unsigned NumArgs = Fn->getFunctionType()->getNumParams();
106  if (NumArgs) {
107    GVArgs.push_back(GVArgc); // Arg #0 = argc.
108    if (NumArgs > 1) {
109      GVArgs.push_back(PTOGV(CreateArgv(this, argv))); // Arg #1 = argv.
110      assert(((char **)GVTOP(GVArgs[1]))[0] &&
111             "argv[0] was null after CreateArgv");
112      if (NumArgs > 2) {
113        std::vector<std::string> EnvVars;
114        for (unsigned i = 0; envp[i]; ++i)
115          EnvVars.push_back(envp[i]);
116        GVArgs.push_back(PTOGV(CreateArgv(this, EnvVars))); // Arg #2 = envp.
117      }
118    }
119  }
120  return runFunction(Fn, GVArgs).IntVal;
121}
122
123
124
125/// If possible, create a JIT, unless the caller specifically requests an
126/// Interpreter or there's an error. If even an Interpreter cannot be created,
127/// NULL is returned.
128///
129ExecutionEngine *ExecutionEngine::create(ModuleProvider *MP,
130                                         bool ForceInterpreter,
131                                         IntrinsicLowering *IL) {
132  ExecutionEngine *EE = 0;
133
134  // Unless the interpreter was explicitly selected, try making a JIT.
135  if (!ForceInterpreter)
136    EE = JIT::create(MP, IL);
137
138  // If we can't make a JIT, make an interpreter instead.
139  if (EE == 0) {
140    try {
141      Module *M = MP->materializeModule();
142      try {
143        EE = Interpreter::create(M, IL);
144      } catch (...) {
145        std::cerr << "Error creating the interpreter!\n";
146      }
147    } catch (std::string& errmsg) {
148      std::cerr << "Error reading the bytecode file: " << errmsg << "\n";
149    } catch (...) {
150      std::cerr << "Error reading the bytecode file!\n";
151    }
152  }
153
154  if (EE == 0) delete IL;
155  return EE;
156}
157
158/// getPointerToGlobal - This returns the address of the specified global
159/// value.  This may involve code generation if it's a function.
160///
161void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
162  if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
163    return getPointerToFunction(F);
164
165  assert(GlobalAddressMap[GV] && "Global hasn't had an address allocated yet?");
166  return GlobalAddressMap[GV];
167}
168
169/// FIXME: document
170///
171GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
172  GenericValue Result;
173
174  if (ConstantExpr *CE = const_cast<ConstantExpr*>(dyn_cast<ConstantExpr>(C))) {
175    switch (CE->getOpcode()) {
176    case Instruction::GetElementPtr: {
177      Result = getConstantValue(CE->getOperand(0));
178      std::vector<Value*> Indexes(CE->op_begin()+1, CE->op_end());
179      uint64_t Offset =
180        TD->getIndexedOffset(CE->getOperand(0)->getType(), Indexes);
181
182      Result.LongVal += Offset;
183      return Result;
184    }
185    case Instruction::Cast: {
186      // We only need to handle a few cases here.  Almost all casts will
187      // automatically fold, just the ones involving pointers won't.
188      //
189      Constant *Op = CE->getOperand(0);
190      GenericValue GV = getConstantValue(Op);
191
192      // Handle cast of pointer to pointer...
193      if (Op->getType()->getTypeID() == C->getType()->getTypeID())
194        return GV;
195
196      // Handle a cast of pointer to any integral type...
197      if (isa<PointerType>(Op->getType()) && C->getType()->isIntegral())
198        return GV;
199
200      // Handle cast of integer to a pointer...
201      if (isa<PointerType>(C->getType()) && Op->getType()->isIntegral())
202        switch (Op->getType()->getTypeID()) {
203        case Type::BoolTyID:    return PTOGV((void*)(uintptr_t)GV.BoolVal);
204        case Type::SByteTyID:   return PTOGV((void*)( intptr_t)GV.SByteVal);
205        case Type::UByteTyID:   return PTOGV((void*)(uintptr_t)GV.UByteVal);
206        case Type::ShortTyID:   return PTOGV((void*)( intptr_t)GV.ShortVal);
207        case Type::UShortTyID:  return PTOGV((void*)(uintptr_t)GV.UShortVal);
208        case Type::IntTyID:     return PTOGV((void*)( intptr_t)GV.IntVal);
209        case Type::UIntTyID:    return PTOGV((void*)(uintptr_t)GV.UIntVal);
210        case Type::LongTyID:    return PTOGV((void*)( intptr_t)GV.LongVal);
211        case Type::ULongTyID:   return PTOGV((void*)(uintptr_t)GV.ULongVal);
212        default: assert(0 && "Unknown integral type!");
213        }
214      break;
215    }
216
217    case Instruction::Add:
218      switch (CE->getOperand(0)->getType()->getTypeID()) {
219      default: assert(0 && "Bad add type!"); abort();
220      case Type::LongTyID:
221      case Type::ULongTyID:
222        Result.LongVal = getConstantValue(CE->getOperand(0)).LongVal +
223                         getConstantValue(CE->getOperand(1)).LongVal;
224        break;
225      case Type::IntTyID:
226      case Type::UIntTyID:
227        Result.IntVal = getConstantValue(CE->getOperand(0)).IntVal +
228                        getConstantValue(CE->getOperand(1)).IntVal;
229        break;
230      case Type::ShortTyID:
231      case Type::UShortTyID:
232        Result.ShortVal = getConstantValue(CE->getOperand(0)).ShortVal +
233                          getConstantValue(CE->getOperand(1)).ShortVal;
234        break;
235      case Type::SByteTyID:
236      case Type::UByteTyID:
237        Result.SByteVal = getConstantValue(CE->getOperand(0)).SByteVal +
238                          getConstantValue(CE->getOperand(1)).SByteVal;
239        break;
240      case Type::FloatTyID:
241        Result.FloatVal = getConstantValue(CE->getOperand(0)).FloatVal +
242                          getConstantValue(CE->getOperand(1)).FloatVal;
243        break;
244      case Type::DoubleTyID:
245        Result.DoubleVal = getConstantValue(CE->getOperand(0)).DoubleVal +
246                           getConstantValue(CE->getOperand(1)).DoubleVal;
247        break;
248      }
249      return Result;
250    default:
251      break;
252    }
253    std::cerr << "ConstantExpr not handled as global var init: " << *CE << "\n";
254    abort();
255  }
256
257  switch (C->getType()->getTypeID()) {
258#define GET_CONST_VAL(TY, CLASS) \
259  case Type::TY##TyID: Result.TY##Val = cast<CLASS>(C)->getValue(); break
260    GET_CONST_VAL(Bool   , ConstantBool);
261    GET_CONST_VAL(UByte  , ConstantUInt);
262    GET_CONST_VAL(SByte  , ConstantSInt);
263    GET_CONST_VAL(UShort , ConstantUInt);
264    GET_CONST_VAL(Short  , ConstantSInt);
265    GET_CONST_VAL(UInt   , ConstantUInt);
266    GET_CONST_VAL(Int    , ConstantSInt);
267    GET_CONST_VAL(ULong  , ConstantUInt);
268    GET_CONST_VAL(Long   , ConstantSInt);
269    GET_CONST_VAL(Float  , ConstantFP);
270    GET_CONST_VAL(Double , ConstantFP);
271#undef GET_CONST_VAL
272  case Type::PointerTyID:
273    if (isa<ConstantPointerNull>(C))
274      Result.PointerVal = 0;
275    else if (const Function *F = dyn_cast<Function>(C))
276      Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
277    else if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
278      Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
279    else
280      assert(0 && "Unknown constant pointer type!");
281    break;
282  default:
283    std::cout << "ERROR: Constant unimp for type: " << *C->getType() << "\n";
284    abort();
285  }
286  return Result;
287}
288
289/// FIXME: document
290///
291void ExecutionEngine::StoreValueToMemory(GenericValue Val, GenericValue *Ptr,
292                                         const Type *Ty) {
293  if (getTargetData().isLittleEndian()) {
294    switch (Ty->getTypeID()) {
295    case Type::BoolTyID:
296    case Type::UByteTyID:
297    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
298    case Type::UShortTyID:
299    case Type::ShortTyID:   Ptr->Untyped[0] = Val.UShortVal & 255;
300                            Ptr->Untyped[1] = (Val.UShortVal >> 8) & 255;
301                            break;
302    Store4BytesLittleEndian:
303    case Type::FloatTyID:
304    case Type::UIntTyID:
305    case Type::IntTyID:     Ptr->Untyped[0] =  Val.UIntVal        & 255;
306                            Ptr->Untyped[1] = (Val.UIntVal >>  8) & 255;
307                            Ptr->Untyped[2] = (Val.UIntVal >> 16) & 255;
308                            Ptr->Untyped[3] = (Val.UIntVal >> 24) & 255;
309                            break;
310    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
311                              goto Store4BytesLittleEndian;
312    case Type::DoubleTyID:
313    case Type::ULongTyID:
314    case Type::LongTyID:    Ptr->Untyped[0] =  Val.ULongVal        & 255;
315                            Ptr->Untyped[1] = (Val.ULongVal >>  8) & 255;
316                            Ptr->Untyped[2] = (Val.ULongVal >> 16) & 255;
317                            Ptr->Untyped[3] = (Val.ULongVal >> 24) & 255;
318                            Ptr->Untyped[4] = (Val.ULongVal >> 32) & 255;
319                            Ptr->Untyped[5] = (Val.ULongVal >> 40) & 255;
320                            Ptr->Untyped[6] = (Val.ULongVal >> 48) & 255;
321                            Ptr->Untyped[7] = (Val.ULongVal >> 56) & 255;
322                            break;
323    default:
324      std::cout << "Cannot store value of type " << *Ty << "!\n";
325    }
326  } else {
327    switch (Ty->getTypeID()) {
328    case Type::BoolTyID:
329    case Type::UByteTyID:
330    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
331    case Type::UShortTyID:
332    case Type::ShortTyID:   Ptr->Untyped[1] = Val.UShortVal & 255;
333                            Ptr->Untyped[0] = (Val.UShortVal >> 8) & 255;
334                            break;
335    Store4BytesBigEndian:
336    case Type::FloatTyID:
337    case Type::UIntTyID:
338    case Type::IntTyID:     Ptr->Untyped[3] =  Val.UIntVal        & 255;
339                            Ptr->Untyped[2] = (Val.UIntVal >>  8) & 255;
340                            Ptr->Untyped[1] = (Val.UIntVal >> 16) & 255;
341                            Ptr->Untyped[0] = (Val.UIntVal >> 24) & 255;
342                            break;
343    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
344                              goto Store4BytesBigEndian;
345    case Type::DoubleTyID:
346    case Type::ULongTyID:
347    case Type::LongTyID:    Ptr->Untyped[7] =  Val.ULongVal        & 255;
348                            Ptr->Untyped[6] = (Val.ULongVal >>  8) & 255;
349                            Ptr->Untyped[5] = (Val.ULongVal >> 16) & 255;
350                            Ptr->Untyped[4] = (Val.ULongVal >> 24) & 255;
351                            Ptr->Untyped[3] = (Val.ULongVal >> 32) & 255;
352                            Ptr->Untyped[2] = (Val.ULongVal >> 40) & 255;
353                            Ptr->Untyped[1] = (Val.ULongVal >> 48) & 255;
354                            Ptr->Untyped[0] = (Val.ULongVal >> 56) & 255;
355                            break;
356    default:
357      std::cout << "Cannot store value of type " << *Ty << "!\n";
358    }
359  }
360}
361
362/// FIXME: document
363///
364GenericValue ExecutionEngine::LoadValueFromMemory(GenericValue *Ptr,
365                                                  const Type *Ty) {
366  GenericValue Result;
367  if (getTargetData().isLittleEndian()) {
368    switch (Ty->getTypeID()) {
369    case Type::BoolTyID:
370    case Type::UByteTyID:
371    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
372    case Type::UShortTyID:
373    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[0] |
374                                              ((unsigned)Ptr->Untyped[1] << 8);
375                            break;
376    Load4BytesLittleEndian:
377    case Type::FloatTyID:
378    case Type::UIntTyID:
379    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[0] |
380                                            ((unsigned)Ptr->Untyped[1] <<  8) |
381                                            ((unsigned)Ptr->Untyped[2] << 16) |
382                                            ((unsigned)Ptr->Untyped[3] << 24);
383                            break;
384    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
385                              goto Load4BytesLittleEndian;
386    case Type::DoubleTyID:
387    case Type::ULongTyID:
388    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[0] |
389                                             ((uint64_t)Ptr->Untyped[1] <<  8) |
390                                             ((uint64_t)Ptr->Untyped[2] << 16) |
391                                             ((uint64_t)Ptr->Untyped[3] << 24) |
392                                             ((uint64_t)Ptr->Untyped[4] << 32) |
393                                             ((uint64_t)Ptr->Untyped[5] << 40) |
394                                             ((uint64_t)Ptr->Untyped[6] << 48) |
395                                             ((uint64_t)Ptr->Untyped[7] << 56);
396                            break;
397    default:
398      std::cout << "Cannot load value of type " << *Ty << "!\n";
399      abort();
400    }
401  } else {
402    switch (Ty->getTypeID()) {
403    case Type::BoolTyID:
404    case Type::UByteTyID:
405    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
406    case Type::UShortTyID:
407    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[1] |
408                                              ((unsigned)Ptr->Untyped[0] << 8);
409                            break;
410    Load4BytesBigEndian:
411    case Type::FloatTyID:
412    case Type::UIntTyID:
413    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[3] |
414                                            ((unsigned)Ptr->Untyped[2] <<  8) |
415                                            ((unsigned)Ptr->Untyped[1] << 16) |
416                                            ((unsigned)Ptr->Untyped[0] << 24);
417                            break;
418    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
419                              goto Load4BytesBigEndian;
420    case Type::DoubleTyID:
421    case Type::ULongTyID:
422    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[7] |
423                                             ((uint64_t)Ptr->Untyped[6] <<  8) |
424                                             ((uint64_t)Ptr->Untyped[5] << 16) |
425                                             ((uint64_t)Ptr->Untyped[4] << 24) |
426                                             ((uint64_t)Ptr->Untyped[3] << 32) |
427                                             ((uint64_t)Ptr->Untyped[2] << 40) |
428                                             ((uint64_t)Ptr->Untyped[1] << 48) |
429                                             ((uint64_t)Ptr->Untyped[0] << 56);
430                            break;
431    default:
432      std::cout << "Cannot load value of type " << *Ty << "!\n";
433      abort();
434    }
435  }
436  return Result;
437}
438
439// InitializeMemory - Recursive function to apply a Constant value into the
440// specified memory location...
441//
442void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
443  if (Init->getType()->isFirstClassType()) {
444    GenericValue Val = getConstantValue(Init);
445    StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
446    return;
447  } else if (isa<ConstantAggregateZero>(Init)) {
448    unsigned Size = getTargetData().getTypeSize(Init->getType());
449    memset(Addr, 0, Size);
450    return;
451  }
452
453  switch (Init->getType()->getTypeID()) {
454  case Type::ArrayTyID: {
455    const ConstantArray *CPA = cast<ConstantArray>(Init);
456    unsigned ElementSize =
457      getTargetData().getTypeSize(cast<ArrayType>(CPA->getType())->getElementType());
458    for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
459      InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
460    return;
461  }
462
463  case Type::StructTyID: {
464    const ConstantStruct *CPS = cast<ConstantStruct>(Init);
465    const StructLayout *SL =
466      getTargetData().getStructLayout(cast<StructType>(CPS->getType()));
467    for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
468      InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->MemberOffsets[i]);
469    return;
470  }
471
472  default:
473    std::cerr << "Bad Type: " << *Init->getType() << "\n";
474    assert(0 && "Unknown constant type to initialize memory with!");
475  }
476}
477
478/// EmitGlobals - Emit all of the global variables to memory, storing their
479/// addresses into GlobalAddress.  This must make sure to copy the contents of
480/// their initializers into the memory.
481///
482void ExecutionEngine::emitGlobals() {
483  const TargetData &TD = getTargetData();
484
485  // Loop over all of the global variables in the program, allocating the memory
486  // to hold them.
487  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
488       I != E; ++I)
489    if (!I->isExternal()) {
490      // Get the type of the global...
491      const Type *Ty = I->getType()->getElementType();
492
493      // Allocate some memory for it!
494      unsigned Size = TD.getTypeSize(Ty);
495      addGlobalMapping(I, new char[Size]);
496    } else {
497      // External variable reference. Try to use the dynamic loader to
498      // get a pointer to it.
499      if (void *SymAddr = GetAddressOfSymbol(I->getName().c_str()))
500        addGlobalMapping(I, SymAddr);
501      else {
502        std::cerr << "Could not resolve external global address: "
503                  << I->getName() << "\n";
504        abort();
505      }
506    }
507
508  // Now that all of the globals are set up in memory, loop through them all and
509  // initialize their contents.
510  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
511       I != E; ++I)
512    if (!I->isExternal())
513      EmitGlobalVariable(I);
514}
515
516// EmitGlobalVariable - This method emits the specified global variable to the
517// address specified in GlobalAddresses, or allocates new memory if it's not
518// already in the map.
519void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
520  void *GA = getPointerToGlobalIfAvailable(GV);
521  DEBUG(std::cerr << "Global '" << GV->getName() << "' -> " << GA << "\n");
522
523  const Type *ElTy = GV->getType()->getElementType();
524  if (GA == 0) {
525    // If it's not already specified, allocate memory for the global.
526    GA = new char[getTargetData().getTypeSize(ElTy)];
527    addGlobalMapping(GV, GA);
528  }
529
530  InitializeMemory(GV->getInitializer(), GA);
531  NumInitBytes += getTargetData().getTypeSize(ElTy);
532  ++NumGlobals;
533}
534