ExecutionEngine.cpp revision e2947531280503a4e73e8d94a6161f68bea857a7 
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 "Support/Debug.h"
27#include "Support/Statistic.h"
28#include "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  GVArgs.push_back(GVArgc); // Arg #0 = argc.
106  GVArgs.push_back(PTOGV(CreateArgv(this, argv))); // Arg #1 = argv.
107  assert(((char **)GVTOP(GVArgs[1]))[0] && "argv[0] was null after CreateArgv");
108
109  std::vector<std::string> EnvVars;
110  for (unsigned i = 0; envp[i]; ++i)
111    EnvVars.push_back(envp[i]);
112  GVArgs.push_back(PTOGV(CreateArgv(this, EnvVars))); // Arg #2 = envp.
113  return runFunction(Fn, GVArgs).IntVal;
114}
115
116
117
118/// If possible, create a JIT, unless the caller specifically requests an
119/// Interpreter or there's an error. If even an Interpreter cannot be created,
120/// NULL is returned.
121///
122ExecutionEngine *ExecutionEngine::create(ModuleProvider *MP,
123                                         bool ForceInterpreter,
124                                         IntrinsicLowering *IL) {
125  ExecutionEngine *EE = 0;
126
127  // Unless the interpreter was explicitly selected, try making a JIT.
128  if (!ForceInterpreter)
129    EE = JIT::create(MP, IL);
130
131  // If we can't make a JIT, make an interpreter instead.
132  if (EE == 0) {
133    try {
134      Module *M = MP->materializeModule();
135      try {
136        EE = Interpreter::create(M, IL);
137      } catch (...) {
138        std::cerr << "Error creating the interpreter!\n";
139      }
140    } catch (std::string& errmsg) {
141      std::cerr << "Error reading the bytecode file: " << errmsg << "\n";
142    } catch (...) {
143      std::cerr << "Error reading the bytecode file!\n";
144    }
145  }
146
147  if (EE == 0) delete IL;
148  return EE;
149}
150
151/// getPointerToGlobal - This returns the address of the specified global
152/// value.  This may involve code generation if it's a function.
153///
154void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
155  if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
156    return getPointerToFunction(F);
157
158  assert(GlobalAddressMap[GV] && "Global hasn't had an address allocated yet?");
159  return GlobalAddressMap[GV];
160}
161
162/// FIXME: document
163///
164GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
165  GenericValue Result;
166
167  if (ConstantExpr *CE = const_cast<ConstantExpr*>(dyn_cast<ConstantExpr>(C))) {
168    switch (CE->getOpcode()) {
169    case Instruction::GetElementPtr: {
170      Result = getConstantValue(CE->getOperand(0));
171      std::vector<Value*> Indexes(CE->op_begin()+1, CE->op_end());
172      uint64_t Offset =
173        TD->getIndexedOffset(CE->getOperand(0)->getType(), Indexes);
174
175      Result.LongVal += Offset;
176      return Result;
177    }
178    case Instruction::Cast: {
179      // We only need to handle a few cases here.  Almost all casts will
180      // automatically fold, just the ones involving pointers won't.
181      //
182      Constant *Op = CE->getOperand(0);
183      GenericValue GV = getConstantValue(Op);
184
185      // Handle cast of pointer to pointer...
186      if (Op->getType()->getTypeID() == C->getType()->getTypeID())
187        return GV;
188
189      // Handle a cast of pointer to any integral type...
190      if (isa<PointerType>(Op->getType()) && C->getType()->isIntegral())
191        return GV;
192
193      // Handle cast of integer to a pointer...
194      if (isa<PointerType>(C->getType()) && Op->getType()->isIntegral())
195        switch (Op->getType()->getTypeID()) {
196        case Type::BoolTyID:    return PTOGV((void*)(uintptr_t)GV.BoolVal);
197        case Type::SByteTyID:   return PTOGV((void*)( intptr_t)GV.SByteVal);
198        case Type::UByteTyID:   return PTOGV((void*)(uintptr_t)GV.UByteVal);
199        case Type::ShortTyID:   return PTOGV((void*)( intptr_t)GV.ShortVal);
200        case Type::UShortTyID:  return PTOGV((void*)(uintptr_t)GV.UShortVal);
201        case Type::IntTyID:     return PTOGV((void*)( intptr_t)GV.IntVal);
202        case Type::UIntTyID:    return PTOGV((void*)(uintptr_t)GV.UIntVal);
203        case Type::LongTyID:    return PTOGV((void*)( intptr_t)GV.LongVal);
204        case Type::ULongTyID:   return PTOGV((void*)(uintptr_t)GV.ULongVal);
205        default: assert(0 && "Unknown integral type!");
206        }
207      break;
208    }
209
210    case Instruction::Add:
211      if (CE->getOperand(0)->getType() == Type::LongTy ||
212          CE->getOperand(0)->getType() == Type::ULongTy)
213        Result.LongVal = getConstantValue(CE->getOperand(0)).LongVal +
214                         getConstantValue(CE->getOperand(1)).LongVal;
215      else
216        break;
217      return Result;
218
219    default:
220      break;
221    }
222    std::cerr << "ConstantExpr not handled as global var init: " << *CE << "\n";
223    abort();
224  }
225
226  switch (C->getType()->getTypeID()) {
227#define GET_CONST_VAL(TY, CLASS) \
228  case Type::TY##TyID: Result.TY##Val = cast<CLASS>(C)->getValue(); break
229    GET_CONST_VAL(Bool   , ConstantBool);
230    GET_CONST_VAL(UByte  , ConstantUInt);
231    GET_CONST_VAL(SByte  , ConstantSInt);
232    GET_CONST_VAL(UShort , ConstantUInt);
233    GET_CONST_VAL(Short  , ConstantSInt);
234    GET_CONST_VAL(UInt   , ConstantUInt);
235    GET_CONST_VAL(Int    , ConstantSInt);
236    GET_CONST_VAL(ULong  , ConstantUInt);
237    GET_CONST_VAL(Long   , ConstantSInt);
238    GET_CONST_VAL(Float  , ConstantFP);
239    GET_CONST_VAL(Double , ConstantFP);
240#undef GET_CONST_VAL
241  case Type::PointerTyID:
242    if (isa<ConstantPointerNull>(C)) {
243      Result.PointerVal = 0;
244    } else if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)){
245      if (Function *F =
246          const_cast<Function*>(dyn_cast<Function>(CPR->getValue())))
247        Result = PTOGV(getPointerToFunctionOrStub(F));
248      else
249        Result = PTOGV(getOrEmitGlobalVariable(
250                           cast<GlobalVariable>(CPR->getValue())));
251
252    } else {
253      assert(0 && "Unknown constant pointer type!");
254    }
255    break;
256  default:
257    std::cout << "ERROR: Constant unimp for type: " << C->getType() << "\n";
258    abort();
259  }
260  return Result;
261}
262
263/// FIXME: document
264///
265void ExecutionEngine::StoreValueToMemory(GenericValue Val, GenericValue *Ptr,
266                                         const Type *Ty) {
267  if (getTargetData().isLittleEndian()) {
268    switch (Ty->getTypeID()) {
269    case Type::BoolTyID:
270    case Type::UByteTyID:
271    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
272    case Type::UShortTyID:
273    case Type::ShortTyID:   Ptr->Untyped[0] = Val.UShortVal & 255;
274                            Ptr->Untyped[1] = (Val.UShortVal >> 8) & 255;
275                            break;
276    Store4BytesLittleEndian:
277    case Type::FloatTyID:
278    case Type::UIntTyID:
279    case Type::IntTyID:     Ptr->Untyped[0] =  Val.UIntVal        & 255;
280                            Ptr->Untyped[1] = (Val.UIntVal >>  8) & 255;
281                            Ptr->Untyped[2] = (Val.UIntVal >> 16) & 255;
282                            Ptr->Untyped[3] = (Val.UIntVal >> 24) & 255;
283                            break;
284    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
285                              goto Store4BytesLittleEndian;
286    case Type::DoubleTyID:
287    case Type::ULongTyID:
288    case Type::LongTyID:    Ptr->Untyped[0] =  Val.ULongVal        & 255;
289                            Ptr->Untyped[1] = (Val.ULongVal >>  8) & 255;
290                            Ptr->Untyped[2] = (Val.ULongVal >> 16) & 255;
291                            Ptr->Untyped[3] = (Val.ULongVal >> 24) & 255;
292                            Ptr->Untyped[4] = (Val.ULongVal >> 32) & 255;
293                            Ptr->Untyped[5] = (Val.ULongVal >> 40) & 255;
294                            Ptr->Untyped[6] = (Val.ULongVal >> 48) & 255;
295                            Ptr->Untyped[7] = (Val.ULongVal >> 56) & 255;
296                            break;
297    default:
298      std::cout << "Cannot store value of type " << Ty << "!\n";
299    }
300  } else {
301    switch (Ty->getTypeID()) {
302    case Type::BoolTyID:
303    case Type::UByteTyID:
304    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
305    case Type::UShortTyID:
306    case Type::ShortTyID:   Ptr->Untyped[1] = Val.UShortVal & 255;
307                            Ptr->Untyped[0] = (Val.UShortVal >> 8) & 255;
308                            break;
309    Store4BytesBigEndian:
310    case Type::FloatTyID:
311    case Type::UIntTyID:
312    case Type::IntTyID:     Ptr->Untyped[3] =  Val.UIntVal        & 255;
313                            Ptr->Untyped[2] = (Val.UIntVal >>  8) & 255;
314                            Ptr->Untyped[1] = (Val.UIntVal >> 16) & 255;
315                            Ptr->Untyped[0] = (Val.UIntVal >> 24) & 255;
316                            break;
317    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
318                              goto Store4BytesBigEndian;
319    case Type::DoubleTyID:
320    case Type::ULongTyID:
321    case Type::LongTyID:    Ptr->Untyped[7] =  Val.ULongVal        & 255;
322                            Ptr->Untyped[6] = (Val.ULongVal >>  8) & 255;
323                            Ptr->Untyped[5] = (Val.ULongVal >> 16) & 255;
324                            Ptr->Untyped[4] = (Val.ULongVal >> 24) & 255;
325                            Ptr->Untyped[3] = (Val.ULongVal >> 32) & 255;
326                            Ptr->Untyped[2] = (Val.ULongVal >> 40) & 255;
327                            Ptr->Untyped[1] = (Val.ULongVal >> 48) & 255;
328                            Ptr->Untyped[0] = (Val.ULongVal >> 56) & 255;
329                            break;
330    default:
331      std::cout << "Cannot store value of type " << Ty << "!\n";
332    }
333  }
334}
335
336/// FIXME: document
337///
338GenericValue ExecutionEngine::LoadValueFromMemory(GenericValue *Ptr,
339                                                  const Type *Ty) {
340  GenericValue Result;
341  if (getTargetData().isLittleEndian()) {
342    switch (Ty->getTypeID()) {
343    case Type::BoolTyID:
344    case Type::UByteTyID:
345    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
346    case Type::UShortTyID:
347    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[0] |
348                                              ((unsigned)Ptr->Untyped[1] << 8);
349                            break;
350    Load4BytesLittleEndian:
351    case Type::FloatTyID:
352    case Type::UIntTyID:
353    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[0] |
354                                            ((unsigned)Ptr->Untyped[1] <<  8) |
355                                            ((unsigned)Ptr->Untyped[2] << 16) |
356                                            ((unsigned)Ptr->Untyped[3] << 24);
357                            break;
358    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
359                              goto Load4BytesLittleEndian;
360    case Type::DoubleTyID:
361    case Type::ULongTyID:
362    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[0] |
363                                             ((uint64_t)Ptr->Untyped[1] <<  8) |
364                                             ((uint64_t)Ptr->Untyped[2] << 16) |
365                                             ((uint64_t)Ptr->Untyped[3] << 24) |
366                                             ((uint64_t)Ptr->Untyped[4] << 32) |
367                                             ((uint64_t)Ptr->Untyped[5] << 40) |
368                                             ((uint64_t)Ptr->Untyped[6] << 48) |
369                                             ((uint64_t)Ptr->Untyped[7] << 56);
370                            break;
371    default:
372      std::cout << "Cannot load value of type " << *Ty << "!\n";
373      abort();
374    }
375  } else {
376    switch (Ty->getTypeID()) {
377    case Type::BoolTyID:
378    case Type::UByteTyID:
379    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
380    case Type::UShortTyID:
381    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[1] |
382                                              ((unsigned)Ptr->Untyped[0] << 8);
383                            break;
384    Load4BytesBigEndian:
385    case Type::FloatTyID:
386    case Type::UIntTyID:
387    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[3] |
388                                            ((unsigned)Ptr->Untyped[2] <<  8) |
389                                            ((unsigned)Ptr->Untyped[1] << 16) |
390                                            ((unsigned)Ptr->Untyped[0] << 24);
391                            break;
392    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
393                              goto Load4BytesBigEndian;
394    case Type::DoubleTyID:
395    case Type::ULongTyID:
396    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[7] |
397                                             ((uint64_t)Ptr->Untyped[6] <<  8) |
398                                             ((uint64_t)Ptr->Untyped[5] << 16) |
399                                             ((uint64_t)Ptr->Untyped[4] << 24) |
400                                             ((uint64_t)Ptr->Untyped[3] << 32) |
401                                             ((uint64_t)Ptr->Untyped[2] << 40) |
402                                             ((uint64_t)Ptr->Untyped[1] << 48) |
403                                             ((uint64_t)Ptr->Untyped[0] << 56);
404                            break;
405    default:
406      std::cout << "Cannot load value of type " << *Ty << "!\n";
407      abort();
408    }
409  }
410  return Result;
411}
412
413// InitializeMemory - Recursive function to apply a Constant value into the
414// specified memory location...
415//
416void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
417  if (Init->getType()->isFirstClassType()) {
418    GenericValue Val = getConstantValue(Init);
419    StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
420    return;
421  } else if (isa<ConstantAggregateZero>(Init)) {
422    unsigned Size = getTargetData().getTypeSize(Init->getType());
423    memset(Addr, 0, Size);
424    return;
425  }
426
427  switch (Init->getType()->getTypeID()) {
428  case Type::ArrayTyID: {
429    const ConstantArray *CPA = cast<ConstantArray>(Init);
430    const std::vector<Use> &Val = CPA->getValues();
431    unsigned ElementSize =
432      getTargetData().getTypeSize(cast<ArrayType>(CPA->getType())->getElementType());
433    for (unsigned i = 0; i < Val.size(); ++i)
434      InitializeMemory(cast<Constant>(Val[i].get()), (char*)Addr+i*ElementSize);
435    return;
436  }
437
438  case Type::StructTyID: {
439    const ConstantStruct *CPS = cast<ConstantStruct>(Init);
440    const StructLayout *SL =
441      getTargetData().getStructLayout(cast<StructType>(CPS->getType()));
442    const std::vector<Use> &Val = CPS->getValues();
443    for (unsigned i = 0; i < Val.size(); ++i)
444      InitializeMemory(cast<Constant>(Val[i].get()),
445                       (char*)Addr+SL->MemberOffsets[i]);
446    return;
447  }
448
449  default:
450    std::cerr << "Bad Type: " << Init->getType() << "\n";
451    assert(0 && "Unknown constant type to initialize memory with!");
452  }
453}
454
455/// EmitGlobals - Emit all of the global variables to memory, storing their
456/// addresses into GlobalAddress.  This must make sure to copy the contents of
457/// their initializers into the memory.
458///
459void ExecutionEngine::emitGlobals() {
460  const TargetData &TD = getTargetData();
461
462  // Loop over all of the global variables in the program, allocating the memory
463  // to hold them.
464  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
465       I != E; ++I)
466    if (!I->isExternal()) {
467      // Get the type of the global...
468      const Type *Ty = I->getType()->getElementType();
469
470      // Allocate some memory for it!
471      unsigned Size = TD.getTypeSize(Ty);
472      addGlobalMapping(I, new char[Size]);
473    } else {
474      // External variable reference. Try to use the dynamic loader to
475      // get a pointer to it.
476      if (void *SymAddr = GetAddressOfSymbol(I->getName().c_str()))
477        addGlobalMapping(I, SymAddr);
478      else {
479        std::cerr << "Could not resolve external global address: "
480                  << I->getName() << "\n";
481        abort();
482      }
483    }
484
485  // Now that all of the globals are set up in memory, loop through them all and
486  // initialize their contents.
487  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
488       I != E; ++I)
489    if (!I->isExternal())
490      EmitGlobalVariable(I);
491}
492
493// EmitGlobalVariable - This method emits the specified global variable to the
494// address specified in GlobalAddresses, or allocates new memory if it's not
495// already in the map.
496void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
497  void *GA = getPointerToGlobalIfAvailable(GV);
498  DEBUG(std::cerr << "Global '" << GV->getName() << "' -> " << GA << "\n");
499
500  const Type *ElTy = GV->getType()->getElementType();
501  if (GA == 0) {
502    // If it's not already specified, allocate memory for the global.
503    GA = new char[getTargetData().getTypeSize(ElTy)];
504    addGlobalMapping(GV, GA);
505  }
506
507  InitializeMemory(GV->getInitializer(), GA);
508  NumInitBytes += getTargetData().getTypeSize(ElTy);
509  ++NumGlobals;
510}
511