ExecutionEngine.cpp revision 20a277e162f971ec1b9c6f2c90a214c177d54f99 
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/VM.h"
18#include "llvm/Constants.h"
19#include "llvm/DerivedTypes.h"
20#include "llvm/Module.h"
21#include "llvm/ModuleProvider.h"
22#include "llvm/ExecutionEngine/ExecutionEngine.h"
23#include "llvm/ExecutionEngine/GenericValue.h"
24#include "llvm/Target/TargetData.h"
25#include "Support/Debug.h"
26#include "Support/Statistic.h"
27#include "Support/DynamicLinker.h"
28#include "Config/dlfcn.h"
29
30Statistic<> NumInitBytes("lli", "Number of bytes of global vars initialized");
31
32ExecutionEngine::ExecutionEngine(ModuleProvider *P) :
33  CurMod(*P->getModule()), MP(P) {
34  assert(P && "ModuleProvider is null?");
35}
36
37ExecutionEngine::ExecutionEngine(Module *M) : CurMod(*M), MP(0) {
38  assert(M && "Module is null?");
39}
40
41ExecutionEngine::~ExecutionEngine() {
42  delete MP;
43}
44
45/// If possible, create a JIT, unless the caller specifically requests an
46/// Interpreter or there's an error. If even an Interpreter cannot be created,
47/// NULL is returned.
48///
49ExecutionEngine *ExecutionEngine::create(ModuleProvider *MP,
50                                         bool ForceInterpreter) {
51  ExecutionEngine *EE = 0;
52
53  // Unless the interpreter was explicitly selected, make a JIT.
54  if (!ForceInterpreter)
55    EE = VM::create(MP);
56
57  // If we can't make a JIT, make an interpreter instead.
58  try {
59    if (EE == 0)
60      EE = Interpreter::create(MP->materializeModule());
61  } catch (...) {
62    EE = 0;
63  }
64  return EE;
65}
66
67/// getPointerToGlobal - This returns the address of the specified global
68/// value.  This may involve code generation if it's a function.
69///
70void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
71  if (Function *F = const_cast<Function*>(dyn_cast<Function>(GV)))
72    return getPointerToFunction(F);
73
74  assert(GlobalAddress[GV] && "Global hasn't had an address allocated yet?");
75  return GlobalAddress[GV];
76}
77
78/// FIXME: document
79///
80GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
81  GenericValue Result;
82
83  if (ConstantExpr *CE = const_cast<ConstantExpr*>(dyn_cast<ConstantExpr>(C))) {
84    switch (CE->getOpcode()) {
85    case Instruction::GetElementPtr: {
86      Result = getConstantValue(CE->getOperand(0));
87      std::vector<Value*> Indexes(CE->op_begin()+1, CE->op_end());
88      uint64_t Offset =
89        TD->getIndexedOffset(CE->getOperand(0)->getType(), Indexes);
90
91      Result.LongVal += Offset;
92      return Result;
93    }
94    case Instruction::Cast: {
95      // We only need to handle a few cases here.  Almost all casts will
96      // automatically fold, just the ones involving pointers won't.
97      //
98      Constant *Op = CE->getOperand(0);
99
100      // Handle cast of pointer to pointer...
101      if (Op->getType()->getPrimitiveID() == C->getType()->getPrimitiveID())
102        return getConstantValue(Op);
103
104      // Handle a cast of pointer to any integral type...
105      if (isa<PointerType>(Op->getType()) && C->getType()->isIntegral())
106        return getConstantValue(Op);
107
108      // Handle cast of long to pointer...
109      if (isa<PointerType>(C->getType()) && (Op->getType() == Type::LongTy ||
110                                             Op->getType() == Type::ULongTy))
111        return getConstantValue(Op);
112      break;
113    }
114
115    case Instruction::Add:
116      if (CE->getOperand(0)->getType() == Type::LongTy ||
117          CE->getOperand(0)->getType() == Type::ULongTy)
118        Result.LongVal = getConstantValue(CE->getOperand(0)).LongVal +
119                         getConstantValue(CE->getOperand(1)).LongVal;
120      else
121        break;
122      return Result;
123
124    default:
125      break;
126    }
127    std::cerr << "ConstantExpr not handled as global var init: " << *CE << "\n";
128    abort();
129  }
130
131  switch (C->getType()->getPrimitiveID()) {
132#define GET_CONST_VAL(TY, CLASS) \
133  case Type::TY##TyID: Result.TY##Val = cast<CLASS>(C)->getValue(); break
134    GET_CONST_VAL(Bool   , ConstantBool);
135    GET_CONST_VAL(UByte  , ConstantUInt);
136    GET_CONST_VAL(SByte  , ConstantSInt);
137    GET_CONST_VAL(UShort , ConstantUInt);
138    GET_CONST_VAL(Short  , ConstantSInt);
139    GET_CONST_VAL(UInt   , ConstantUInt);
140    GET_CONST_VAL(Int    , ConstantSInt);
141    GET_CONST_VAL(ULong  , ConstantUInt);
142    GET_CONST_VAL(Long   , ConstantSInt);
143    GET_CONST_VAL(Float  , ConstantFP);
144    GET_CONST_VAL(Double , ConstantFP);
145#undef GET_CONST_VAL
146  case Type::PointerTyID:
147    if (isa<ConstantPointerNull>(C)) {
148      Result.PointerVal = 0;
149    } else if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)){
150      Result = PTOGV(getPointerToGlobal(CPR->getValue()));
151
152    } else {
153      assert(0 && "Unknown constant pointer type!");
154    }
155    break;
156  default:
157    std::cout << "ERROR: Constant unimp for type: " << C->getType() << "\n";
158    abort();
159  }
160  return Result;
161}
162
163/// FIXME: document
164///
165void ExecutionEngine::StoreValueToMemory(GenericValue Val, GenericValue *Ptr,
166                                         const Type *Ty) {
167  if (getTargetData().isLittleEndian()) {
168    switch (Ty->getPrimitiveID()) {
169    case Type::BoolTyID:
170    case Type::UByteTyID:
171    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
172    case Type::UShortTyID:
173    case Type::ShortTyID:   Ptr->Untyped[0] = Val.UShortVal & 255;
174                            Ptr->Untyped[1] = (Val.UShortVal >> 8) & 255;
175                            break;
176    Store4BytesLittleEndian:
177    case Type::FloatTyID:
178    case Type::UIntTyID:
179    case Type::IntTyID:     Ptr->Untyped[0] =  Val.UIntVal        & 255;
180                            Ptr->Untyped[1] = (Val.UIntVal >>  8) & 255;
181                            Ptr->Untyped[2] = (Val.UIntVal >> 16) & 255;
182                            Ptr->Untyped[3] = (Val.UIntVal >> 24) & 255;
183                            break;
184    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
185                              goto Store4BytesLittleEndian;
186    case Type::DoubleTyID:
187    case Type::ULongTyID:
188    case Type::LongTyID:    Ptr->Untyped[0] =  Val.ULongVal        & 255;
189                            Ptr->Untyped[1] = (Val.ULongVal >>  8) & 255;
190                            Ptr->Untyped[2] = (Val.ULongVal >> 16) & 255;
191                            Ptr->Untyped[3] = (Val.ULongVal >> 24) & 255;
192                            Ptr->Untyped[4] = (Val.ULongVal >> 32) & 255;
193                            Ptr->Untyped[5] = (Val.ULongVal >> 40) & 255;
194                            Ptr->Untyped[6] = (Val.ULongVal >> 48) & 255;
195                            Ptr->Untyped[7] = (Val.ULongVal >> 56) & 255;
196                            break;
197    default:
198      std::cout << "Cannot store value of type " << Ty << "!\n";
199    }
200  } else {
201    switch (Ty->getPrimitiveID()) {
202    case Type::BoolTyID:
203    case Type::UByteTyID:
204    case Type::SByteTyID:   Ptr->Untyped[0] = Val.UByteVal; break;
205    case Type::UShortTyID:
206    case Type::ShortTyID:   Ptr->Untyped[1] = Val.UShortVal & 255;
207                            Ptr->Untyped[0] = (Val.UShortVal >> 8) & 255;
208                            break;
209    Store4BytesBigEndian:
210    case Type::FloatTyID:
211    case Type::UIntTyID:
212    case Type::IntTyID:     Ptr->Untyped[3] =  Val.UIntVal        & 255;
213                            Ptr->Untyped[2] = (Val.UIntVal >>  8) & 255;
214                            Ptr->Untyped[1] = (Val.UIntVal >> 16) & 255;
215                            Ptr->Untyped[0] = (Val.UIntVal >> 24) & 255;
216                            break;
217    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
218                              goto Store4BytesBigEndian;
219    case Type::DoubleTyID:
220    case Type::ULongTyID:
221    case Type::LongTyID:    Ptr->Untyped[7] =  Val.ULongVal        & 255;
222                            Ptr->Untyped[6] = (Val.ULongVal >>  8) & 255;
223                            Ptr->Untyped[5] = (Val.ULongVal >> 16) & 255;
224                            Ptr->Untyped[4] = (Val.ULongVal >> 24) & 255;
225                            Ptr->Untyped[3] = (Val.ULongVal >> 32) & 255;
226                            Ptr->Untyped[2] = (Val.ULongVal >> 40) & 255;
227                            Ptr->Untyped[1] = (Val.ULongVal >> 48) & 255;
228                            Ptr->Untyped[0] = (Val.ULongVal >> 56) & 255;
229                            break;
230    default:
231      std::cout << "Cannot store value of type " << Ty << "!\n";
232    }
233  }
234}
235
236/// FIXME: document
237///
238GenericValue ExecutionEngine::LoadValueFromMemory(GenericValue *Ptr,
239                                                  const Type *Ty) {
240  GenericValue Result;
241  if (getTargetData().isLittleEndian()) {
242    switch (Ty->getPrimitiveID()) {
243    case Type::BoolTyID:
244    case Type::UByteTyID:
245    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
246    case Type::UShortTyID:
247    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[0] |
248                                              ((unsigned)Ptr->Untyped[1] << 8);
249                            break;
250    Load4BytesLittleEndian:
251    case Type::FloatTyID:
252    case Type::UIntTyID:
253    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[0] |
254                                            ((unsigned)Ptr->Untyped[1] <<  8) |
255                                            ((unsigned)Ptr->Untyped[2] << 16) |
256                                            ((unsigned)Ptr->Untyped[3] << 24);
257                            break;
258    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
259                              goto Load4BytesLittleEndian;
260    case Type::DoubleTyID:
261    case Type::ULongTyID:
262    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[0] |
263                                             ((uint64_t)Ptr->Untyped[1] <<  8) |
264                                             ((uint64_t)Ptr->Untyped[2] << 16) |
265                                             ((uint64_t)Ptr->Untyped[3] << 24) |
266                                             ((uint64_t)Ptr->Untyped[4] << 32) |
267                                             ((uint64_t)Ptr->Untyped[5] << 40) |
268                                             ((uint64_t)Ptr->Untyped[6] << 48) |
269                                             ((uint64_t)Ptr->Untyped[7] << 56);
270                            break;
271    default:
272      std::cout << "Cannot load value of type " << *Ty << "!\n";
273      abort();
274    }
275  } else {
276    switch (Ty->getPrimitiveID()) {
277    case Type::BoolTyID:
278    case Type::UByteTyID:
279    case Type::SByteTyID:   Result.UByteVal = Ptr->Untyped[0]; break;
280    case Type::UShortTyID:
281    case Type::ShortTyID:   Result.UShortVal = (unsigned)Ptr->Untyped[1] |
282                                              ((unsigned)Ptr->Untyped[0] << 8);
283                            break;
284    Load4BytesBigEndian:
285    case Type::FloatTyID:
286    case Type::UIntTyID:
287    case Type::IntTyID:     Result.UIntVal = (unsigned)Ptr->Untyped[3] |
288                                            ((unsigned)Ptr->Untyped[2] <<  8) |
289                                            ((unsigned)Ptr->Untyped[1] << 16) |
290                                            ((unsigned)Ptr->Untyped[0] << 24);
291                            break;
292    case Type::PointerTyID: if (getTargetData().getPointerSize() == 4)
293                              goto Load4BytesBigEndian;
294    case Type::DoubleTyID:
295    case Type::ULongTyID:
296    case Type::LongTyID:    Result.ULongVal = (uint64_t)Ptr->Untyped[7] |
297                                             ((uint64_t)Ptr->Untyped[6] <<  8) |
298                                             ((uint64_t)Ptr->Untyped[5] << 16) |
299                                             ((uint64_t)Ptr->Untyped[4] << 24) |
300                                             ((uint64_t)Ptr->Untyped[3] << 32) |
301                                             ((uint64_t)Ptr->Untyped[2] << 40) |
302                                             ((uint64_t)Ptr->Untyped[1] << 48) |
303                                             ((uint64_t)Ptr->Untyped[0] << 56);
304                            break;
305    default:
306      std::cout << "Cannot load value of type " << *Ty << "!\n";
307      abort();
308    }
309  }
310  return Result;
311}
312
313// InitializeMemory - Recursive function to apply a Constant value into the
314// specified memory location...
315//
316void ExecutionEngine::InitializeMemory(const Constant *Init, void *Addr) {
317  if (Init->getType()->isFirstClassType()) {
318    GenericValue Val = getConstantValue(Init);
319    StoreValueToMemory(Val, (GenericValue*)Addr, Init->getType());
320    return;
321  }
322
323  switch (Init->getType()->getPrimitiveID()) {
324  case Type::ArrayTyID: {
325    const ConstantArray *CPA = cast<ConstantArray>(Init);
326    const std::vector<Use> &Val = CPA->getValues();
327    unsigned ElementSize =
328      getTargetData().getTypeSize(cast<ArrayType>(CPA->getType())->getElementType());
329    for (unsigned i = 0; i < Val.size(); ++i)
330      InitializeMemory(cast<Constant>(Val[i].get()), (char*)Addr+i*ElementSize);
331    return;
332  }
333
334  case Type::StructTyID: {
335    const ConstantStruct *CPS = cast<ConstantStruct>(Init);
336    const StructLayout *SL =
337      getTargetData().getStructLayout(cast<StructType>(CPS->getType()));
338    const std::vector<Use> &Val = CPS->getValues();
339    for (unsigned i = 0; i < Val.size(); ++i)
340      InitializeMemory(cast<Constant>(Val[i].get()),
341                       (char*)Addr+SL->MemberOffsets[i]);
342    return;
343  }
344
345  default:
346    std::cerr << "Bad Type: " << Init->getType() << "\n";
347    assert(0 && "Unknown constant type to initialize memory with!");
348  }
349}
350
351/// EmitGlobals - Emit all of the global variables to memory, storing their
352/// addresses into GlobalAddress.  This must make sure to copy the contents of
353/// their initializers into the memory.
354///
355void ExecutionEngine::emitGlobals() {
356  const TargetData &TD = getTargetData();
357
358  // Loop over all of the global variables in the program, allocating the memory
359  // to hold them.
360  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
361       I != E; ++I)
362    if (!I->isExternal()) {
363      // Get the type of the global...
364      const Type *Ty = I->getType()->getElementType();
365
366      // Allocate some memory for it!
367      unsigned Size = TD.getTypeSize(Ty);
368      GlobalAddress[I] = new char[Size];
369      NumInitBytes += Size;
370
371      DEBUG(std::cerr << "Global '" << I->getName() << "' -> "
372                      << (void*)GlobalAddress[I] << "\n");
373    } else {
374      // External variable reference. Try to use the dynamic loader to
375      // get a pointer to it.
376      if (void *SymAddr = GetAddressOfSymbol(I->getName().c_str()))
377        GlobalAddress[I] = SymAddr;
378      else {
379        std::cerr << "Could not resolve external global address: "
380                  << I->getName() << "\n";
381        abort();
382      }
383    }
384
385  // Now that all of the globals are set up in memory, loop through them all and
386  // initialize their contents.
387  for (Module::giterator I = getModule().gbegin(), E = getModule().gend();
388       I != E; ++I)
389    if (!I->isExternal())
390      InitializeMemory(I->getInitializer(), GlobalAddress[I]);
391}
392
393