ExecutionEngine.cpp revision 6f335f905c76187a7baf70a227fa843061473afe 
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  if (isa<UndefValue>(C)) return Result;
174
175  if (ConstantExpr *CE = const_cast<ConstantExpr*>(dyn_cast<ConstantExpr>(C))) {
176    switch (CE->getOpcode()) {
177    case Instruction::GetElementPtr: {
178      Result = getConstantValue(CE->getOperand(0));
179      std::vector<Value*> Indexes(CE->op_begin()+1, CE->op_end());
180      uint64_t Offset =
181        TD->getIndexedOffset(CE->getOperand(0)->getType(), Indexes);
182
183      Result.LongVal += Offset;
184      return Result;
185    }
186    case Instruction::Cast: {
187      // We only need to handle a few cases here.  Almost all casts will
188      // automatically fold, just the ones involving pointers won't.
189      //
190      Constant *Op = CE->getOperand(0);
191      GenericValue GV = getConstantValue(Op);
192
193      // Handle cast of pointer to pointer...
194      if (Op->getType()->getTypeID() == C->getType()->getTypeID())
195        return GV;
196
197      // Handle a cast of pointer to any integral type...
198      if (isa<PointerType>(Op->getType()) && C->getType()->isIntegral())
199        return GV;
200
201      // Handle cast of integer to a pointer...
202      if (isa<PointerType>(C->getType()) && Op->getType()->isIntegral())
203        switch (Op->getType()->getTypeID()) {
204        case Type::BoolTyID:    return PTOGV((void*)(uintptr_t)GV.BoolVal);
205        case Type::SByteTyID:   return PTOGV((void*)( intptr_t)GV.SByteVal);
206        case Type::UByteTyID:   return PTOGV((void*)(uintptr_t)GV.UByteVal);
207        case Type::ShortTyID:   return PTOGV((void*)( intptr_t)GV.ShortVal);
208        case Type::UShortTyID:  return PTOGV((void*)(uintptr_t)GV.UShortVal);
209        case Type::IntTyID:     return PTOGV((void*)( intptr_t)GV.IntVal);
210        case Type::UIntTyID:    return PTOGV((void*)(uintptr_t)GV.UIntVal);
211        case Type::LongTyID:    return PTOGV((void*)( intptr_t)GV.LongVal);
212        case Type::ULongTyID:   return PTOGV((void*)(uintptr_t)GV.ULongVal);
213        default: assert(0 && "Unknown integral type!");
214        }
215      break;
216    }
217
218    case Instruction::Add:
219      switch (CE->getOperand(0)->getType()->getTypeID()) {
220      default: assert(0 && "Bad add type!"); abort();
221      case Type::LongTyID:
222      case Type::ULongTyID:
223        Result.LongVal = getConstantValue(CE->getOperand(0)).LongVal +
224                         getConstantValue(CE->getOperand(1)).LongVal;
225        break;
226      case Type::IntTyID:
227      case Type::UIntTyID:
228        Result.IntVal = getConstantValue(CE->getOperand(0)).IntVal +
229                        getConstantValue(CE->getOperand(1)).IntVal;
230        break;
231      case Type::ShortTyID:
232      case Type::UShortTyID:
233        Result.ShortVal = getConstantValue(CE->getOperand(0)).ShortVal +
234                          getConstantValue(CE->getOperand(1)).ShortVal;
235        break;
236      case Type::SByteTyID:
237      case Type::UByteTyID:
238        Result.SByteVal = getConstantValue(CE->getOperand(0)).SByteVal +
239                          getConstantValue(CE->getOperand(1)).SByteVal;
240        break;
241      case Type::FloatTyID:
242        Result.FloatVal = getConstantValue(CE->getOperand(0)).FloatVal +
243                          getConstantValue(CE->getOperand(1)).FloatVal;
244        break;
245      case Type::DoubleTyID:
246        Result.DoubleVal = getConstantValue(CE->getOperand(0)).DoubleVal +
247                           getConstantValue(CE->getOperand(1)).DoubleVal;
248        break;
249      }
250      return Result;
251    default:
252      break;
253    }
254    std::cerr << "ConstantExpr not handled as global var init: " << *CE << "\n";
255    abort();
256  }
257
258  switch (C->getType()->getTypeID()) {
259#define GET_CONST_VAL(TY, CLASS) \
260  case Type::TY##TyID: Result.TY##Val = cast<CLASS>(C)->getValue(); break
261    GET_CONST_VAL(Bool   , ConstantBool);
262    GET_CONST_VAL(UByte  , ConstantUInt);
263    GET_CONST_VAL(SByte  , ConstantSInt);
264    GET_CONST_VAL(UShort , ConstantUInt);
265    GET_CONST_VAL(Short  , ConstantSInt);
266    GET_CONST_VAL(UInt   , ConstantUInt);
267    GET_CONST_VAL(Int    , ConstantSInt);
268    GET_CONST_VAL(ULong  , ConstantUInt);
269    GET_CONST_VAL(Long   , ConstantSInt);
270    GET_CONST_VAL(Float  , ConstantFP);
271    GET_CONST_VAL(Double , ConstantFP);
272#undef GET_CONST_VAL
273  case Type::PointerTyID:
274    if (isa<ConstantPointerNull>(C))
275      Result.PointerVal = 0;
276    else if (const Function *F = dyn_cast<Function>(C))
277      Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
278    else if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
279      Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
280    else
281      assert(0 && "Unknown constant pointer type!");
282    break;
283  default:
284    std::cout << "ERROR: Constant unimp for type: " << *C->getType() << "\n";
285    abort();
286  }
287  return Result;
288}
289
290/// FIXME: document
291///
292void ExecutionEngine::StoreValueToMemory(GenericValue Val, GenericValue *Ptr,
293                                         const Type *Ty) {
294  if (getTargetData().isLittleEndian()) {
295    switch (Ty->getTypeID()) {
296    case Type::BoolTyID:
297    case Type::UByteTyID:
298    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
299    case Type::UShortTyID:
300    case Type::ShortTyID:   Ptr->Untyped[0] = Val.UShortVal & 255;
301                            Ptr->Untyped[1] = (Val.UShortVal >> 8) & 255;
302                            break;
303    Store4BytesLittleEndian:
304    case Type::FloatTyID:
305    case Type::UIntTyID:
306    case Type::IntTyID:     Ptr->Untyped[0] =  Val.UIntVal        & 255;
307                            Ptr->Untyped[1] = (Val.UIntVal >>  8) & 255;
308                            Ptr->Untyped[2] = (Val.UIntVal >> 16) & 255;
309                            Ptr->Untyped[3] = (Val.UIntVal >> 24) & 255;
310                            break;
311    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
312                              goto Store4BytesLittleEndian;
313    case Type::DoubleTyID:
314    case Type::ULongTyID:
315    case Type::LongTyID:    Ptr->Untyped[0] =  Val.ULongVal        & 255;
316                            Ptr->Untyped[1] = (Val.ULongVal >>  8) & 255;
317                            Ptr->Untyped[2] = (Val.ULongVal >> 16) & 255;
318                            Ptr->Untyped[3] = (Val.ULongVal >> 24) & 255;
319                            Ptr->Untyped[4] = (Val.ULongVal >> 32) & 255;
320                            Ptr->Untyped[5] = (Val.ULongVal >> 40) & 255;
321                            Ptr->Untyped[6] = (Val.ULongVal >> 48) & 255;
322                            Ptr->Untyped[7] = (Val.ULongVal >> 56) & 255;
323                            break;
324    default:
325      std::cout << "Cannot store value of type " << *Ty << "!\n";
326    }
327  } else {
328    switch (Ty->getTypeID()) {
329    case Type::BoolTyID:
330    case Type::UByteTyID:
331    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
332    case Type::UShortTyID:
333    case Type::ShortTyID:   Ptr->Untyped[1] = Val.UShortVal & 255;
334                            Ptr->Untyped[0] = (Val.UShortVal >> 8) & 255;
335                            break;
336    Store4BytesBigEndian:
337    case Type::FloatTyID:
338    case Type::UIntTyID:
339    case Type::IntTyID:     Ptr->Untyped[3] =  Val.UIntVal        & 255;
340                            Ptr->Untyped[2] = (Val.UIntVal >>  8) & 255;
341                            Ptr->Untyped[1] = (Val.UIntVal >> 16) & 255;
342                            Ptr->Untyped[0] = (Val.UIntVal >> 24) & 255;
343                            break;
344    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
345                              goto Store4BytesBigEndian;
346    case Type::DoubleTyID:
347    case Type::ULongTyID:
348    case Type::LongTyID:    Ptr->Untyped[7] =  Val.ULongVal        & 255;
349                            Ptr->Untyped[6] = (Val.ULongVal >>  8) & 255;
350                            Ptr->Untyped[5] = (Val.ULongVal >> 16) & 255;
351                            Ptr->Untyped[4] = (Val.ULongVal >> 24) & 255;
352                            Ptr->Untyped[3] = (Val.ULongVal >> 32) & 255;
353                            Ptr->Untyped[2] = (Val.ULongVal >> 40) & 255;
354                            Ptr->Untyped[1] = (Val.ULongVal >> 48) & 255;
355                            Ptr->Untyped[0] = (Val.ULongVal >> 56) & 255;
356                            break;
357    default:
358      std::cout << "Cannot store value of type " << *Ty << "!\n";
359    }
360  }
361}
362
363/// FIXME: document
364///
365GenericValue ExecutionEngine::LoadValueFromMemory(GenericValue *Ptr,
366                                                  const Type *Ty) {
367  GenericValue Result;
368  if (getTargetData().isLittleEndian()) {
369    switch (Ty->getTypeID()) {
370    case Type::BoolTyID:
371    case Type::UByteTyID:
372    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
373    case Type::UShortTyID:
374    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[0] |
375                                              ((unsigned)Ptr->Untyped[1] << 8);
376                            break;
377    Load4BytesLittleEndian:
378    case Type::FloatTyID:
379    case Type::UIntTyID:
380    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[0] |
381                                            ((unsigned)Ptr->Untyped[1] <<  8) |
382                                            ((unsigned)Ptr->Untyped[2] << 16) |
383                                            ((unsigned)Ptr->Untyped[3] << 24);
384                            break;
385    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
386                              goto Load4BytesLittleEndian;
387    case Type::DoubleTyID:
388    case Type::ULongTyID:
389    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[0] |
390                                             ((uint64_t)Ptr->Untyped[1] <<  8) |
391                                             ((uint64_t)Ptr->Untyped[2] << 16) |
392                                             ((uint64_t)Ptr->Untyped[3] << 24) |
393                                             ((uint64_t)Ptr->Untyped[4] << 32) |
394                                             ((uint64_t)Ptr->Untyped[5] << 40) |
395                                             ((uint64_t)Ptr->Untyped[6] << 48) |
396                                             ((uint64_t)Ptr->Untyped[7] << 56);
397                            break;
398    default:
399      std::cout << "Cannot load value of type " << *Ty << "!\n";
400      abort();
401    }
402  } else {
403    switch (Ty->getTypeID()) {
404    case Type::BoolTyID:
405    case Type::UByteTyID:
406    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
407    case Type::UShortTyID:
408    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[1] |
409                                              ((unsigned)Ptr->Untyped[0] << 8);
410                            break;
411    Load4BytesBigEndian:
412    case Type::FloatTyID:
413    case Type::UIntTyID:
414    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[3] |
415                                            ((unsigned)Ptr->Untyped[2] <<  8) |
416                                            ((unsigned)Ptr->Untyped[1] << 16) |
417                                            ((unsigned)Ptr->Untyped[0] << 24);
418                            break;
419    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
420                              goto Load4BytesBigEndian;
421    case Type::DoubleTyID:
422    case Type::ULongTyID:
423    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[7] |
424                                             ((uint64_t)Ptr->Untyped[6] <<  8) |
425                                             ((uint64_t)Ptr->Untyped[5] << 16) |
426                                             ((uint64_t)Ptr->Untyped[4] << 24) |
427                                             ((uint64_t)Ptr->Untyped[3] << 32) |
428                                             ((uint64_t)Ptr->Untyped[2] << 40) |
429                                             ((uint64_t)Ptr->Untyped[1] << 48) |
430                                             ((uint64_t)Ptr->Untyped[0] << 56);
431                            break;
432    default:
433      std::cout << "Cannot load value of type " << *Ty << "!\n";
434      abort();
435    }
436  }
437  return Result;
438}
439
440// InitializeMemory - Recursive function to apply a Constant value into the
441// specified memory location...
442//
443void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
444  if (isa<UndefValue>(Init)) {
445    return;
446  } else if (Init->getType()->isFirstClassType()) {
447    GenericValue Val = getConstantValue(Init);
448    StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
449    return;
450  } else if (isa<ConstantAggregateZero>(Init)) {
451    unsigned Size = getTargetData().getTypeSize(Init->getType());
452    memset(Addr, 0, Size);
453    return;
454  }
455
456  switch (Init->getType()->getTypeID()) {
457  case Type::ArrayTyID: {
458    const ConstantArray *CPA = cast<ConstantArray>(Init);
459    unsigned ElementSize =
460      getTargetData().getTypeSize(cast<ArrayType>(CPA->getType())->getElementType());
461    for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
462      InitializeMemory(CPA->getOperand(i), (char*)Addr+i*ElementSize);
463    return;
464  }
465
466  case Type::StructTyID: {
467    const ConstantStruct *CPS = cast<ConstantStruct>(Init);
468    const StructLayout *SL =
469      getTargetData().getStructLayout(cast<StructType>(CPS->getType()));
470    for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
471      InitializeMemory(CPS->getOperand(i), (char*)Addr+SL->MemberOffsets[i]);
472    return;
473  }
474
475  default:
476    std::cerr << "Bad Type: " << *Init->getType() << "\n";
477    assert(0 && "Unknown constant type to initialize memory with!");
478  }
479}
480
481/// EmitGlobals - Emit all of the global variables to memory, storing their
482/// addresses into GlobalAddress.  This must make sure to copy the contents of
483/// their initializers into the memory.
484///
485void ExecutionEngine::emitGlobals() {
486  const TargetData &TD = getTargetData();
487
488  // Loop over all of the global variables in the program, allocating the memory
489  // to hold them.
490  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
491       I != E; ++I)
492    if (!I->isExternal()) {
493      // Get the type of the global...
494      const Type *Ty = I->getType()->getElementType();
495
496      // Allocate some memory for it!
497      unsigned Size = TD.getTypeSize(Ty);
498      addGlobalMapping(I, new char[Size]);
499    } else {
500      // External variable reference. Try to use the dynamic loader to
501      // get a pointer to it.
502      if (void *SymAddr = GetAddressOfSymbol(I->getName().c_str()))
503        addGlobalMapping(I, SymAddr);
504      else {
505        std::cerr << "Could not resolve external global address: "
506                  << I->getName() << "\n";
507        abort();
508      }
509    }
510
511  // Now that all of the globals are set up in memory, loop through them all and
512  // initialize their contents.
513  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
514       I != E; ++I)
515    if (!I->isExternal())
516      EmitGlobalVariable(I);
517}
518
519// EmitGlobalVariable - This method emits the specified global variable to the
520// address specified in GlobalAddresses, or allocates new memory if it's not
521// already in the map.
522void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
523  void *GA = getPointerToGlobalIfAvailable(GV);
524  DEBUG(std::cerr << "Global '" << GV->getName() << "' -> " << GA << "\n");
525
526  const Type *ElTy = GV->getType()->getElementType();
527  if (GA == 0) {
528    // If it's not already specified, allocate memory for the global.
529    GA = new char[getTargetData().getTypeSize(ElTy)];
530    addGlobalMapping(GV, GA);
531  }
532
533  InitializeMemory(GV->getInitializer(), GA);
534  NumInitBytes += getTargetData().getTypeSize(ElTy);
535  ++NumGlobals;
536}
537