BitcodeReader.cpp revision 866971474ced63f725bd3dbf10fdb9e3badb7d9e 
1//===- BitcodeReader.cpp - Internal BitcodeReader implementation ----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by Chris Lattner and is distributed under
6// the University of Illinois Open Source License.  See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This header defines the BitcodeReader class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Bitcode/ReaderWriter.h"
15#include "BitcodeReader.h"
16#include "llvm/Constants.h"
17#include "llvm/DerivedTypes.h"
18#include "llvm/Module.h"
19#include "llvm/ADT/SmallString.h"
20#include "llvm/Support/MathExtras.h"
21#include "llvm/Support/MemoryBuffer.h"
22using namespace llvm;
23
24BitcodeReader::~BitcodeReader() {
25  delete Buffer;
26}
27
28
29/// ConvertToString - Convert a string from a record into an std::string, return
30/// true on failure.
31template<typename StrTy>
32static bool ConvertToString(SmallVector<uint64_t, 64> &Record, unsigned Idx,
33                            StrTy &Result) {
34  if (Record.size() < Idx+1 || Record.size() < Record[Idx]+Idx+1)
35    return true;
36
37  for (unsigned i = 0, e = Record[Idx]; i != e; ++i)
38    Result += (char)Record[Idx+i+1];
39  return false;
40}
41
42static GlobalValue::LinkageTypes GetDecodedLinkage(unsigned Val) {
43  switch (Val) {
44  default: // Map unknown/new linkages to external
45  case 0: return GlobalValue::ExternalLinkage;
46  case 1: return GlobalValue::WeakLinkage;
47  case 2: return GlobalValue::AppendingLinkage;
48  case 3: return GlobalValue::InternalLinkage;
49  case 4: return GlobalValue::LinkOnceLinkage;
50  case 5: return GlobalValue::DLLImportLinkage;
51  case 6: return GlobalValue::DLLExportLinkage;
52  case 7: return GlobalValue::ExternalWeakLinkage;
53  }
54}
55
56static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
57  switch (Val) {
58  default: // Map unknown visibilities to default.
59  case 0: return GlobalValue::DefaultVisibility;
60  case 1: return GlobalValue::HiddenVisibility;
61  case 2: return GlobalValue::ProtectedVisibility;
62  }
63}
64
65static int GetDecodedCastOpcode(unsigned Val) {
66  switch (Val) {
67  default: return -1;
68  case bitc::CAST_TRUNC   : return Instruction::Trunc;
69  case bitc::CAST_ZEXT    : return Instruction::ZExt;
70  case bitc::CAST_SEXT    : return Instruction::SExt;
71  case bitc::CAST_FPTOUI  : return Instruction::FPToUI;
72  case bitc::CAST_FPTOSI  : return Instruction::FPToSI;
73  case bitc::CAST_UITOFP  : return Instruction::UIToFP;
74  case bitc::CAST_SITOFP  : return Instruction::SIToFP;
75  case bitc::CAST_FPTRUNC : return Instruction::FPTrunc;
76  case bitc::CAST_FPEXT   : return Instruction::FPExt;
77  case bitc::CAST_PTRTOINT: return Instruction::PtrToInt;
78  case bitc::CAST_INTTOPTR: return Instruction::IntToPtr;
79  case bitc::CAST_BITCAST : return Instruction::BitCast;
80  }
81}
82static int GetDecodedBinaryOpcode(unsigned Val, const Type *Ty) {
83  switch (Val) {
84  default: return -1;
85  case bitc::BINOP_ADD:  return Instruction::Add;
86  case bitc::BINOP_SUB:  return Instruction::Sub;
87  case bitc::BINOP_MUL:  return Instruction::Mul;
88  case bitc::BINOP_UDIV: return Instruction::UDiv;
89  case bitc::BINOP_SDIV:
90    return Ty->isFPOrFPVector() ? Instruction::FDiv : Instruction::SDiv;
91  case bitc::BINOP_UREM: return Instruction::URem;
92  case bitc::BINOP_SREM:
93    return Ty->isFPOrFPVector() ? Instruction::FRem : Instruction::SRem;
94  case bitc::BINOP_SHL:  return Instruction::Shl;
95  case bitc::BINOP_LSHR: return Instruction::LShr;
96  case bitc::BINOP_ASHR: return Instruction::AShr;
97  case bitc::BINOP_AND:  return Instruction::And;
98  case bitc::BINOP_OR:   return Instruction::Or;
99  case bitc::BINOP_XOR:  return Instruction::Xor;
100  }
101}
102
103
104namespace {
105  /// @brief A class for maintaining the slot number definition
106  /// as a placeholder for the actual definition for forward constants defs.
107  class ConstantPlaceHolder : public ConstantExpr {
108    ConstantPlaceHolder();                       // DO NOT IMPLEMENT
109    void operator=(const ConstantPlaceHolder &); // DO NOT IMPLEMENT
110  public:
111    Use Op;
112    ConstantPlaceHolder(const Type *Ty)
113      : ConstantExpr(Ty, Instruction::UserOp1, &Op, 1),
114        Op(UndefValue::get(Type::Int32Ty), this) {
115    }
116  };
117}
118
119Constant *BitcodeReaderValueList::getConstantFwdRef(unsigned Idx,
120                                                    const Type *Ty) {
121  if (Idx >= size()) {
122    // Insert a bunch of null values.
123    Uses.resize(Idx+1);
124    OperandList = &Uses[0];
125    NumOperands = Idx+1;
126  }
127
128  if (Uses[Idx]) {
129    assert(Ty == getOperand(Idx)->getType() &&
130           "Type mismatch in constant table!");
131    return cast<Constant>(getOperand(Idx));
132  }
133
134  // Create and return a placeholder, which will later be RAUW'd.
135  Constant *C = new ConstantPlaceHolder(Ty);
136  Uses[Idx].init(C, this);
137  return C;
138}
139
140
141const Type *BitcodeReader::getTypeByID(unsigned ID, bool isTypeTable) {
142  // If the TypeID is in range, return it.
143  if (ID < TypeList.size())
144    return TypeList[ID].get();
145  if (!isTypeTable) return 0;
146
147  // The type table allows forward references.  Push as many Opaque types as
148  // needed to get up to ID.
149  while (TypeList.size() <= ID)
150    TypeList.push_back(OpaqueType::get());
151  return TypeList.back().get();
152}
153
154
155bool BitcodeReader::ParseTypeTable() {
156  if (Stream.EnterSubBlock())
157    return Error("Malformed block record");
158
159  if (!TypeList.empty())
160    return Error("Multiple TYPE_BLOCKs found!");
161
162  SmallVector<uint64_t, 64> Record;
163  unsigned NumRecords = 0;
164
165  // Read all the records for this type table.
166  while (1) {
167    unsigned Code = Stream.ReadCode();
168    if (Code == bitc::END_BLOCK) {
169      if (NumRecords != TypeList.size())
170        return Error("Invalid type forward reference in TYPE_BLOCK");
171      if (Stream.ReadBlockEnd())
172        return Error("Error at end of type table block");
173      return false;
174    }
175
176    if (Code == bitc::ENTER_SUBBLOCK) {
177      // No known subblocks, always skip them.
178      Stream.ReadSubBlockID();
179      if (Stream.SkipBlock())
180        return Error("Malformed block record");
181      continue;
182    }
183
184    if (Code == bitc::DEFINE_ABBREV) {
185      Stream.ReadAbbrevRecord();
186      continue;
187    }
188
189    // Read a record.
190    Record.clear();
191    const Type *ResultTy = 0;
192    switch (Stream.ReadRecord(Code, Record)) {
193    default:  // Default behavior: unknown type.
194      ResultTy = 0;
195      break;
196    case bitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
197      // TYPE_CODE_NUMENTRY contains a count of the number of types in the
198      // type list.  This allows us to reserve space.
199      if (Record.size() < 1)
200        return Error("Invalid TYPE_CODE_NUMENTRY record");
201      TypeList.reserve(Record[0]);
202      continue;
203    case bitc::TYPE_CODE_META:      // TYPE_CODE_META: [metacode]...
204      // No metadata supported yet.
205      if (Record.size() < 1)
206        return Error("Invalid TYPE_CODE_META record");
207      continue;
208
209    case bitc::TYPE_CODE_VOID:      // VOID
210      ResultTy = Type::VoidTy;
211      break;
212    case bitc::TYPE_CODE_FLOAT:     // FLOAT
213      ResultTy = Type::FloatTy;
214      break;
215    case bitc::TYPE_CODE_DOUBLE:    // DOUBLE
216      ResultTy = Type::DoubleTy;
217      break;
218    case bitc::TYPE_CODE_LABEL:     // LABEL
219      ResultTy = Type::LabelTy;
220      break;
221    case bitc::TYPE_CODE_OPAQUE:    // OPAQUE
222      ResultTy = 0;
223      break;
224    case bitc::TYPE_CODE_INTEGER:   // INTEGER: [width]
225      if (Record.size() < 1)
226        return Error("Invalid Integer type record");
227
228      ResultTy = IntegerType::get(Record[0]);
229      break;
230    case bitc::TYPE_CODE_POINTER:   // POINTER: [pointee type]
231      if (Record.size() < 1)
232        return Error("Invalid POINTER type record");
233      ResultTy = PointerType::get(getTypeByID(Record[0], true));
234      break;
235    case bitc::TYPE_CODE_FUNCTION: {
236      // FUNCTION: [vararg, retty, #pararms, paramty N]
237      if (Record.size() < 3 || Record.size() < Record[2]+3)
238        return Error("Invalid FUNCTION type record");
239      std::vector<const Type*> ArgTys;
240      for (unsigned i = 0, e = Record[2]; i != e; ++i)
241        ArgTys.push_back(getTypeByID(Record[3+i], true));
242
243      // FIXME: PARAM TYS.
244      ResultTy = FunctionType::get(getTypeByID(Record[1], true), ArgTys,
245                                   Record[0]);
246      break;
247    }
248    case bitc::TYPE_CODE_STRUCT: {  // STRUCT: [ispacked, #elts, eltty x N]
249      if (Record.size() < 2 || Record.size() < Record[1]+2)
250        return Error("Invalid STRUCT type record");
251      std::vector<const Type*> EltTys;
252      for (unsigned i = 0, e = Record[1]; i != e; ++i)
253        EltTys.push_back(getTypeByID(Record[2+i], true));
254      ResultTy = StructType::get(EltTys, Record[0]);
255      break;
256    }
257    case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
258      if (Record.size() < 2)
259        return Error("Invalid ARRAY type record");
260      ResultTy = ArrayType::get(getTypeByID(Record[1], true), Record[0]);
261      break;
262    case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
263      if (Record.size() < 2)
264        return Error("Invalid VECTOR type record");
265      ResultTy = VectorType::get(getTypeByID(Record[1], true), Record[0]);
266      break;
267    }
268
269    if (NumRecords == TypeList.size()) {
270      // If this is a new type slot, just append it.
271      TypeList.push_back(ResultTy ? ResultTy : OpaqueType::get());
272      ++NumRecords;
273    } else if (ResultTy == 0) {
274      // Otherwise, this was forward referenced, so an opaque type was created,
275      // but the result type is actually just an opaque.  Leave the one we
276      // created previously.
277      ++NumRecords;
278    } else {
279      // Otherwise, this was forward referenced, so an opaque type was created.
280      // Resolve the opaque type to the real type now.
281      assert(NumRecords < TypeList.size() && "Typelist imbalance");
282      const OpaqueType *OldTy = cast<OpaqueType>(TypeList[NumRecords++].get());
283
284      // Don't directly push the new type on the Tab. Instead we want to replace
285      // the opaque type we previously inserted with the new concrete value. The
286      // refinement from the abstract (opaque) type to the new type causes all
287      // uses of the abstract type to use the concrete type (NewTy). This will
288      // also cause the opaque type to be deleted.
289      const_cast<OpaqueType*>(OldTy)->refineAbstractTypeTo(ResultTy);
290
291      // This should have replaced the old opaque type with the new type in the
292      // value table... or with a preexisting type that was already in the
293      // system.  Let's just make sure it did.
294      assert(TypeList[NumRecords-1].get() != OldTy &&
295             "refineAbstractType didn't work!");
296    }
297  }
298}
299
300
301bool BitcodeReader::ParseTypeSymbolTable() {
302  if (Stream.EnterSubBlock())
303    return Error("Malformed block record");
304
305  SmallVector<uint64_t, 64> Record;
306
307  // Read all the records for this type table.
308  std::string TypeName;
309  while (1) {
310    unsigned Code = Stream.ReadCode();
311    if (Code == bitc::END_BLOCK) {
312      if (Stream.ReadBlockEnd())
313        return Error("Error at end of type symbol table block");
314      return false;
315    }
316
317    if (Code == bitc::ENTER_SUBBLOCK) {
318      // No known subblocks, always skip them.
319      Stream.ReadSubBlockID();
320      if (Stream.SkipBlock())
321        return Error("Malformed block record");
322      continue;
323    }
324
325    if (Code == bitc::DEFINE_ABBREV) {
326      Stream.ReadAbbrevRecord();
327      continue;
328    }
329
330    // Read a record.
331    Record.clear();
332    switch (Stream.ReadRecord(Code, Record)) {
333    default:  // Default behavior: unknown type.
334      break;
335    case bitc::TST_CODE_ENTRY:    // TST_ENTRY: [typeid, namelen, namechar x N]
336      if (ConvertToString(Record, 1, TypeName))
337        return Error("Invalid TST_ENTRY record");
338      unsigned TypeID = Record[0];
339      if (TypeID >= TypeList.size())
340        return Error("Invalid Type ID in TST_ENTRY record");
341
342      TheModule->addTypeName(TypeName, TypeList[TypeID].get());
343      TypeName.clear();
344      break;
345    }
346  }
347}
348
349bool BitcodeReader::ParseValueSymbolTable() {
350  if (Stream.EnterSubBlock())
351    return Error("Malformed block record");
352
353  SmallVector<uint64_t, 64> Record;
354
355  // Read all the records for this value table.
356  SmallString<128> ValueName;
357  while (1) {
358    unsigned Code = Stream.ReadCode();
359    if (Code == bitc::END_BLOCK) {
360      if (Stream.ReadBlockEnd())
361        return Error("Error at end of value symbol table block");
362      return false;
363    }
364    if (Code == bitc::ENTER_SUBBLOCK) {
365      // No known subblocks, always skip them.
366      Stream.ReadSubBlockID();
367      if (Stream.SkipBlock())
368        return Error("Malformed block record");
369      continue;
370    }
371
372    if (Code == bitc::DEFINE_ABBREV) {
373      Stream.ReadAbbrevRecord();
374      continue;
375    }
376
377    // Read a record.
378    Record.clear();
379    switch (Stream.ReadRecord(Code, Record)) {
380    default:  // Default behavior: unknown type.
381      break;
382    case bitc::TST_CODE_ENTRY:    // VST_ENTRY: [valueid, namelen, namechar x N]
383      if (ConvertToString(Record, 1, ValueName))
384        return Error("Invalid TST_ENTRY record");
385      unsigned ValueID = Record[0];
386      if (ValueID >= ValueList.size())
387        return Error("Invalid Value ID in VST_ENTRY record");
388      Value *V = ValueList[ValueID];
389
390      V->setName(&ValueName[0], ValueName.size());
391      ValueName.clear();
392      break;
393    }
394  }
395}
396
397/// DecodeSignRotatedValue - Decode a signed value stored with the sign bit in
398/// the LSB for dense VBR encoding.
399static uint64_t DecodeSignRotatedValue(uint64_t V) {
400  if ((V & 1) == 0)
401    return V >> 1;
402  if (V != 1)
403    return -(V >> 1);
404  // There is no such thing as -0 with integers.  "-0" really means MININT.
405  return 1ULL << 63;
406}
407
408/// ResolveGlobalAndAliasInits - Resolve all of the initializers for global
409/// values and aliases that we can.
410bool BitcodeReader::ResolveGlobalAndAliasInits() {
411  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
412  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
413
414  GlobalInitWorklist.swap(GlobalInits);
415  AliasInitWorklist.swap(AliasInits);
416
417  while (!GlobalInitWorklist.empty()) {
418    unsigned ValID = GlobalInitWorklist.back().second;
419    if (ValID >= ValueList.size()) {
420      // Not ready to resolve this yet, it requires something later in the file.
421      GlobalInits.push_back(GlobalInitWorklist.back());
422    } else {
423      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
424        GlobalInitWorklist.back().first->setInitializer(C);
425      else
426        return Error("Global variable initializer is not a constant!");
427    }
428    GlobalInitWorklist.pop_back();
429  }
430
431  while (!AliasInitWorklist.empty()) {
432    unsigned ValID = AliasInitWorklist.back().second;
433    if (ValID >= ValueList.size()) {
434      AliasInits.push_back(AliasInitWorklist.back());
435    } else {
436      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
437        AliasInitWorklist.back().first->setAliasee(C);
438      else
439        return Error("Alias initializer is not a constant!");
440    }
441    AliasInitWorklist.pop_back();
442  }
443  return false;
444}
445
446
447bool BitcodeReader::ParseConstants() {
448  if (Stream.EnterSubBlock())
449    return Error("Malformed block record");
450
451  SmallVector<uint64_t, 64> Record;
452
453  // Read all the records for this value table.
454  const Type *CurTy = Type::Int32Ty;
455  unsigned NextCstNo = ValueList.size();
456  while (1) {
457    unsigned Code = Stream.ReadCode();
458    if (Code == bitc::END_BLOCK) {
459      if (NextCstNo != ValueList.size())
460        return Error("Invalid constant reference!");
461
462      if (Stream.ReadBlockEnd())
463        return Error("Error at end of constants block");
464      return false;
465    }
466
467    if (Code == bitc::ENTER_SUBBLOCK) {
468      // No known subblocks, always skip them.
469      Stream.ReadSubBlockID();
470      if (Stream.SkipBlock())
471        return Error("Malformed block record");
472      continue;
473    }
474
475    if (Code == bitc::DEFINE_ABBREV) {
476      Stream.ReadAbbrevRecord();
477      continue;
478    }
479
480    // Read a record.
481    Record.clear();
482    Value *V = 0;
483    switch (Stream.ReadRecord(Code, Record)) {
484    default:  // Default behavior: unknown constant
485    case bitc::CST_CODE_UNDEF:     // UNDEF
486      V = UndefValue::get(CurTy);
487      break;
488    case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
489      if (Record.empty())
490        return Error("Malformed CST_SETTYPE record");
491      if (Record[0] >= TypeList.size())
492        return Error("Invalid Type ID in CST_SETTYPE record");
493      CurTy = TypeList[Record[0]];
494      continue;  // Skip the ValueList manipulation.
495    case bitc::CST_CODE_NULL:      // NULL
496      V = Constant::getNullValue(CurTy);
497      break;
498    case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
499      if (!isa<IntegerType>(CurTy) || Record.empty())
500        return Error("Invalid CST_INTEGER record");
501      V = ConstantInt::get(CurTy, DecodeSignRotatedValue(Record[0]));
502      break;
503    case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n, n x intval]
504      if (!isa<IntegerType>(CurTy) || Record.empty() ||
505          Record.size() < Record[0]+1)
506        return Error("Invalid WIDE_INTEGER record");
507
508      unsigned NumWords = Record[0];
509      SmallVector<uint64_t, 8> Words;
510      Words.resize(NumWords);
511      for (unsigned i = 0; i != NumWords; ++i)
512        Words[i] = DecodeSignRotatedValue(Record[i+1]);
513      V = ConstantInt::get(APInt(cast<IntegerType>(CurTy)->getBitWidth(),
514                                 NumWords, &Words[0]));
515      break;
516    }
517    case bitc::CST_CODE_FLOAT:     // FLOAT: [fpval]
518      if (Record.empty())
519        return Error("Invalid FLOAT record");
520      if (CurTy == Type::FloatTy)
521        V = ConstantFP::get(CurTy, BitsToFloat(Record[0]));
522      else if (CurTy == Type::DoubleTy)
523        V = ConstantFP::get(CurTy, BitsToDouble(Record[0]));
524      else
525        V = UndefValue::get(CurTy);
526      break;
527
528    case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n, n x value number]
529      if (Record.empty() || Record.size() < Record[0]+1)
530        return Error("Invalid CST_AGGREGATE record");
531
532      unsigned Size = Record[0];
533      std::vector<Constant*> Elts;
534
535      if (const StructType *STy = dyn_cast<StructType>(CurTy)) {
536        for (unsigned i = 0; i != Size; ++i)
537          Elts.push_back(ValueList.getConstantFwdRef(Record[i+1],
538                                                     STy->getElementType(i)));
539        V = ConstantStruct::get(STy, Elts);
540      } else if (const ArrayType *ATy = dyn_cast<ArrayType>(CurTy)) {
541        const Type *EltTy = ATy->getElementType();
542        for (unsigned i = 0; i != Size; ++i)
543          Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], EltTy));
544        V = ConstantArray::get(ATy, Elts);
545      } else if (const VectorType *VTy = dyn_cast<VectorType>(CurTy)) {
546        const Type *EltTy = VTy->getElementType();
547        for (unsigned i = 0; i != Size; ++i)
548          Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], EltTy));
549        V = ConstantVector::get(Elts);
550      } else {
551        V = UndefValue::get(CurTy);
552      }
553      break;
554    }
555
556    case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
557      if (Record.size() < 3) return Error("Invalid CE_BINOP record");
558      int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
559      if (Opc < 0) {
560        V = UndefValue::get(CurTy);  // Unknown binop.
561      } else {
562        Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
563        Constant *RHS = ValueList.getConstantFwdRef(Record[2], CurTy);
564        V = ConstantExpr::get(Opc, LHS, RHS);
565      }
566      break;
567    }
568    case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
569      if (Record.size() < 3) return Error("Invalid CE_CAST record");
570      int Opc = GetDecodedCastOpcode(Record[0]);
571      if (Opc < 0) {
572        V = UndefValue::get(CurTy);  // Unknown cast.
573      } else {
574        const Type *OpTy = getTypeByID(Record[1]);
575        Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
576        V = ConstantExpr::getCast(Opc, Op, CurTy);
577      }
578      break;
579    }
580    case bitc::CST_CODE_CE_GEP: {  // CE_GEP:        [n x operands]
581      if ((Record.size() & 1) == 0) return Error("Invalid CE_GEP record");
582      SmallVector<Constant*, 16> Elts;
583      for (unsigned i = 1, e = Record.size(); i != e; i += 2) {
584        const Type *ElTy = getTypeByID(Record[i]);
585        if (!ElTy) return Error("Invalid CE_GEP record");
586        Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
587      }
588      V = ConstantExpr::getGetElementPtr(Elts[0], &Elts[1], Elts.size()-1);
589      break;
590    }
591    case bitc::CST_CODE_CE_SELECT:  // CE_SELECT: [opval#, opval#, opval#]
592      if (Record.size() < 3) return Error("Invalid CE_SELECT record");
593      V = ConstantExpr::getSelect(ValueList.getConstantFwdRef(Record[0],
594                                                              Type::Int1Ty),
595                                  ValueList.getConstantFwdRef(Record[1],CurTy),
596                                  ValueList.getConstantFwdRef(Record[2],CurTy));
597      break;
598    case bitc::CST_CODE_CE_EXTRACTELT: { // CE_EXTRACTELT: [opty, opval, opval]
599      if (Record.size() < 3) return Error("Invalid CE_EXTRACTELT record");
600      const VectorType *OpTy =
601        dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
602      if (OpTy == 0) return Error("Invalid CE_EXTRACTELT record");
603      Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
604      Constant *Op1 = ValueList.getConstantFwdRef(Record[2],
605                                                  OpTy->getElementType());
606      V = ConstantExpr::getExtractElement(Op0, Op1);
607      break;
608    }
609    case bitc::CST_CODE_CE_INSERTELT: { // CE_INSERTELT: [opval, opval, opval]
610      const VectorType *OpTy = dyn_cast<VectorType>(CurTy);
611      if (Record.size() < 3 || OpTy == 0)
612        return Error("Invalid CE_INSERTELT record");
613      Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
614      Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
615                                                  OpTy->getElementType());
616      Constant *Op2 = ValueList.getConstantFwdRef(Record[2], Type::Int32Ty);
617      V = ConstantExpr::getInsertElement(Op0, Op1, Op2);
618      break;
619    }
620    case bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
621      const VectorType *OpTy = dyn_cast<VectorType>(CurTy);
622      if (Record.size() < 3 || OpTy == 0)
623        return Error("Invalid CE_INSERTELT record");
624      Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
625      Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
626      const Type *ShufTy=VectorType::get(Type::Int32Ty, OpTy->getNumElements());
627      Constant *Op2 = ValueList.getConstantFwdRef(Record[2], ShufTy);
628      V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
629      break;
630    }
631    case bitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
632      if (Record.size() < 4) return Error("Invalid CE_CMP record");
633      const Type *OpTy = getTypeByID(Record[0]);
634      if (OpTy == 0) return Error("Invalid CE_CMP record");
635      Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
636      Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
637
638      if (OpTy->isFloatingPoint())
639        V = ConstantExpr::getFCmp(Record[3], Op0, Op1);
640      else
641        V = ConstantExpr::getICmp(Record[3], Op0, Op1);
642      break;
643    }
644    }
645
646    if (NextCstNo == ValueList.size())
647      ValueList.push_back(V);
648    else if (ValueList[NextCstNo] == 0)
649      ValueList.initVal(NextCstNo, V);
650    else {
651      // If there was a forward reference to this constant,
652      Value *OldV = ValueList[NextCstNo];
653      ValueList.setOperand(NextCstNo, V);
654      OldV->replaceAllUsesWith(V);
655      delete OldV;
656    }
657
658    ++NextCstNo;
659  }
660}
661
662/// ParseFunction - When we see the block for a function body, remember where it
663/// is and then skip it.  This lets us lazily deserialize the functions.
664bool BitcodeReader::ParseFunction() {
665  // Get the function we are talking about.
666  if (FunctionsWithBodies.empty())
667    return Error("Insufficient function protos");
668
669  Function *Fn = FunctionsWithBodies.back();
670  FunctionsWithBodies.pop_back();
671
672  // Save the current stream state.
673  uint64_t CurBit = Stream.GetCurrentBitNo();
674  DeferredFunctionInfo[Fn] = std::make_pair(CurBit, Fn->getLinkage());
675
676  // Set the functions linkage to GhostLinkage so we know it is lazily
677  // deserialized.
678  Fn->setLinkage(GlobalValue::GhostLinkage);
679
680  // Skip over the function block for now.
681  if (Stream.SkipBlock())
682    return Error("Malformed block record");
683  return false;
684}
685
686bool BitcodeReader::ParseModule(const std::string &ModuleID) {
687  // Reject multiple MODULE_BLOCK's in a single bitstream.
688  if (TheModule)
689    return Error("Multiple MODULE_BLOCKs in same stream");
690
691  if (Stream.EnterSubBlock())
692    return Error("Malformed block record");
693
694  // Otherwise, create the module.
695  TheModule = new Module(ModuleID);
696
697  SmallVector<uint64_t, 64> Record;
698  std::vector<std::string> SectionTable;
699
700  // Read all the records for this module.
701  while (!Stream.AtEndOfStream()) {
702    unsigned Code = Stream.ReadCode();
703    if (Code == bitc::END_BLOCK) {
704      ResolveGlobalAndAliasInits();
705      if (!GlobalInits.empty() || !AliasInits.empty())
706        return Error("Malformed global initializer set");
707      if (!FunctionsWithBodies.empty())
708        return Error("Too few function bodies found");
709      if (Stream.ReadBlockEnd())
710        return Error("Error at end of module block");
711      return false;
712    }
713
714    if (Code == bitc::ENTER_SUBBLOCK) {
715      switch (Stream.ReadSubBlockID()) {
716      default:  // Skip unknown content.
717        if (Stream.SkipBlock())
718          return Error("Malformed block record");
719        break;
720      case bitc::TYPE_BLOCK_ID:
721        if (ParseTypeTable())
722          return true;
723        break;
724      case bitc::TYPE_SYMTAB_BLOCK_ID:
725        if (ParseTypeSymbolTable())
726          return true;
727        break;
728      case bitc::VALUE_SYMTAB_BLOCK_ID:
729        if (ParseValueSymbolTable())
730          return true;
731        break;
732      case bitc::CONSTANTS_BLOCK_ID:
733        if (ParseConstants() || ResolveGlobalAndAliasInits())
734          return true;
735        break;
736      case bitc::FUNCTION_BLOCK_ID:
737        // If this is the first function body we've seen, reverse the
738        // FunctionsWithBodies list.
739        if (!HasReversedFunctionsWithBodies) {
740          std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
741          HasReversedFunctionsWithBodies = true;
742        }
743
744        if (ParseFunction())
745          return true;
746        break;
747      }
748      continue;
749    }
750
751    if (Code == bitc::DEFINE_ABBREV) {
752      Stream.ReadAbbrevRecord();
753      continue;
754    }
755
756    // Read a record.
757    switch (Stream.ReadRecord(Code, Record)) {
758    default: break;  // Default behavior, ignore unknown content.
759    case bitc::MODULE_CODE_VERSION:  // VERSION: [version#]
760      if (Record.size() < 1)
761        return Error("Malformed MODULE_CODE_VERSION");
762      // Only version #0 is supported so far.
763      if (Record[0] != 0)
764        return Error("Unknown bitstream version!");
765      break;
766    case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strlen, strchr x N]
767      std::string S;
768      if (ConvertToString(Record, 0, S))
769        return Error("Invalid MODULE_CODE_TRIPLE record");
770      TheModule->setTargetTriple(S);
771      break;
772    }
773    case bitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strlen, strchr x N]
774      std::string S;
775      if (ConvertToString(Record, 0, S))
776        return Error("Invalid MODULE_CODE_DATALAYOUT record");
777      TheModule->setDataLayout(S);
778      break;
779    }
780    case bitc::MODULE_CODE_ASM: {  // ASM: [strlen, strchr x N]
781      std::string S;
782      if (ConvertToString(Record, 0, S))
783        return Error("Invalid MODULE_CODE_ASM record");
784      TheModule->setModuleInlineAsm(S);
785      break;
786    }
787    case bitc::MODULE_CODE_DEPLIB: {  // DEPLIB: [strlen, strchr x N]
788      std::string S;
789      if (ConvertToString(Record, 0, S))
790        return Error("Invalid MODULE_CODE_DEPLIB record");
791      TheModule->addLibrary(S);
792      break;
793    }
794    case bitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strlen, strchr x N]
795      std::string S;
796      if (ConvertToString(Record, 0, S))
797        return Error("Invalid MODULE_CODE_SECTIONNAME record");
798      SectionTable.push_back(S);
799      break;
800    }
801    // GLOBALVAR: [type, isconst, initid,
802    //             linkage, alignment, section, visibility, threadlocal]
803    case bitc::MODULE_CODE_GLOBALVAR: {
804      if (Record.size() < 6)
805        return Error("Invalid MODULE_CODE_GLOBALVAR record");
806      const Type *Ty = getTypeByID(Record[0]);
807      if (!isa<PointerType>(Ty))
808        return Error("Global not a pointer type!");
809      Ty = cast<PointerType>(Ty)->getElementType();
810
811      bool isConstant = Record[1];
812      GlobalValue::LinkageTypes Linkage = GetDecodedLinkage(Record[3]);
813      unsigned Alignment = (1 << Record[4]) >> 1;
814      std::string Section;
815      if (Record[5]) {
816        if (Record[5]-1 >= SectionTable.size())
817          return Error("Invalid section ID");
818        Section = SectionTable[Record[5]-1];
819      }
820      GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
821      if (Record.size() >= 6) Visibility = GetDecodedVisibility(Record[6]);
822      bool isThreadLocal = false;
823      if (Record.size() >= 7) isThreadLocal = Record[7];
824
825      GlobalVariable *NewGV =
826        new GlobalVariable(Ty, isConstant, Linkage, 0, "", TheModule);
827      NewGV->setAlignment(Alignment);
828      if (!Section.empty())
829        NewGV->setSection(Section);
830      NewGV->setVisibility(Visibility);
831      NewGV->setThreadLocal(isThreadLocal);
832
833      ValueList.push_back(NewGV);
834
835      // Remember which value to use for the global initializer.
836      if (unsigned InitID = Record[2])
837        GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
838      break;
839    }
840    // FUNCTION:  [type, callingconv, isproto, linkage, alignment, section,
841    //             visibility]
842    case bitc::MODULE_CODE_FUNCTION: {
843      if (Record.size() < 7)
844        return Error("Invalid MODULE_CODE_FUNCTION record");
845      const Type *Ty = getTypeByID(Record[0]);
846      if (!isa<PointerType>(Ty))
847        return Error("Function not a pointer type!");
848      const FunctionType *FTy =
849        dyn_cast<FunctionType>(cast<PointerType>(Ty)->getElementType());
850      if (!FTy)
851        return Error("Function not a pointer to function type!");
852
853      Function *Func = new Function(FTy, GlobalValue::ExternalLinkage,
854                                    "", TheModule);
855
856      Func->setCallingConv(Record[1]);
857      bool isProto = Record[2];
858      Func->setLinkage(GetDecodedLinkage(Record[3]));
859      Func->setAlignment((1 << Record[4]) >> 1);
860      if (Record[5]) {
861        if (Record[5]-1 >= SectionTable.size())
862          return Error("Invalid section ID");
863        Func->setSection(SectionTable[Record[5]-1]);
864      }
865      Func->setVisibility(GetDecodedVisibility(Record[6]));
866
867      ValueList.push_back(Func);
868
869      // If this is a function with a body, remember the prototype we are
870      // creating now, so that we can match up the body with them later.
871      if (!isProto)
872        FunctionsWithBodies.push_back(Func);
873      break;
874    }
875    // ALIAS: [alias type, aliasee val#, linkage]
876    case bitc::MODULE_CODE_ALIAS: {
877      if (Record.size() < 3)
878        return Error("Invalid MODULE_ALIAS record");
879      const Type *Ty = getTypeByID(Record[0]);
880      if (!isa<PointerType>(Ty))
881        return Error("Function not a pointer type!");
882
883      GlobalAlias *NewGA = new GlobalAlias(Ty, GetDecodedLinkage(Record[2]),
884                                           "", 0, TheModule);
885      ValueList.push_back(NewGA);
886      AliasInits.push_back(std::make_pair(NewGA, Record[1]));
887      break;
888    }
889    /// MODULE_CODE_PURGEVALS: [numvals]
890    case bitc::MODULE_CODE_PURGEVALS:
891      // Trim down the value list to the specified size.
892      if (Record.size() < 1 || Record[0] > ValueList.size())
893        return Error("Invalid MODULE_PURGEVALS record");
894      ValueList.shrinkTo(Record[0]);
895      break;
896    }
897    Record.clear();
898  }
899
900  return Error("Premature end of bitstream");
901}
902
903
904bool BitcodeReader::ParseBitcode() {
905  TheModule = 0;
906
907  if (Buffer->getBufferSize() & 3)
908    return Error("Bitcode stream should be a multiple of 4 bytes in length");
909
910  unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
911  Stream.init(BufPtr, BufPtr+Buffer->getBufferSize());
912
913  // Sniff for the signature.
914  if (Stream.Read(8) != 'B' ||
915      Stream.Read(8) != 'C' ||
916      Stream.Read(4) != 0x0 ||
917      Stream.Read(4) != 0xC ||
918      Stream.Read(4) != 0xE ||
919      Stream.Read(4) != 0xD)
920    return Error("Invalid bitcode signature");
921
922  // We expect a number of well-defined blocks, though we don't necessarily
923  // need to understand them all.
924  while (!Stream.AtEndOfStream()) {
925    unsigned Code = Stream.ReadCode();
926
927    if (Code != bitc::ENTER_SUBBLOCK)
928      return Error("Invalid record at top-level");
929
930    unsigned BlockID = Stream.ReadSubBlockID();
931
932    // We only know the MODULE subblock ID.
933    if (BlockID == bitc::MODULE_BLOCK_ID) {
934      if (ParseModule(Buffer->getBufferIdentifier()))
935        return true;
936    } else if (Stream.SkipBlock()) {
937      return Error("Malformed block record");
938    }
939  }
940
941  return false;
942}
943
944
945bool BitcodeReader::materializeFunction(Function *F, std::string *ErrInfo) {
946  // If it already is material, ignore the request.
947  if (!F->hasNotBeenReadFromBytecode()) return false;
948
949  DenseMap<Function*, std::pair<uint64_t, unsigned> >::iterator DFII =
950    DeferredFunctionInfo.find(F);
951  assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
952
953  // Move the bit stream to the saved position of the deferred function body and
954  // restore the real linkage type for the function.
955  Stream.JumpToBit(DFII->second.first);
956  F->setLinkage((GlobalValue::LinkageTypes)DFII->second.second);
957  DeferredFunctionInfo.erase(DFII);
958
959  return false;
960}
961
962
963//===----------------------------------------------------------------------===//
964// External interface
965//===----------------------------------------------------------------------===//
966
967/// getBitcodeModuleProvider - lazy function-at-a-time loading from a file.
968///
969ModuleProvider *llvm::getBitcodeModuleProvider(MemoryBuffer *Buffer,
970                                               std::string *ErrMsg) {
971  BitcodeReader *R = new BitcodeReader(Buffer);
972  if (R->ParseBitcode()) {
973    if (ErrMsg)
974      *ErrMsg = R->getErrorString();
975
976    // Don't let the BitcodeReader dtor delete 'Buffer'.
977    R->releaseMemoryBuffer();
978    delete R;
979    return 0;
980  }
981  return R;
982}
983
984/// ParseBitcodeFile - Read the specified bitcode file, returning the module.
985/// If an error occurs, return null and fill in *ErrMsg if non-null.
986Module *llvm::ParseBitcodeFile(MemoryBuffer *Buffer, std::string *ErrMsg){
987  BitcodeReader *R;
988  R = static_cast<BitcodeReader*>(getBitcodeModuleProvider(Buffer, ErrMsg));
989  if (!R) return 0;
990
991  // Read the whole module, get a pointer to it, tell ModuleProvider not to
992  // delete it when its dtor is run.
993  Module *M = R->releaseModule(ErrMsg);
994
995  // Don't let the BitcodeReader dtor delete 'Buffer'.
996  R->releaseMemoryBuffer();
997  delete R;
998  return M;
999}
1000