BitcodeWriter.cpp revision 081134741b40b342fb2f85722c9cea5d412489a8 
1//===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Bitcode writer implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Bitcode/ReaderWriter.h"
15#include "llvm/Bitcode/BitstreamWriter.h"
16#include "llvm/Bitcode/LLVMBitCodes.h"
17#include "ValueEnumerator.h"
18#include "llvm/Constants.h"
19#include "llvm/DerivedTypes.h"
20#include "llvm/InlineAsm.h"
21#include "llvm/Instructions.h"
22#include "llvm/Module.h"
23#include "llvm/Operator.h"
24#include "llvm/TypeSymbolTable.h"
25#include "llvm/ValueSymbolTable.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/MathExtras.h"
28#include "llvm/Support/raw_ostream.h"
29#include "llvm/System/Program.h"
30using namespace llvm;
31
32/// These are manifest constants used by the bitcode writer. They do not need to
33/// be kept in sync with the reader, but need to be consistent within this file.
34enum {
35  CurVersion = 0,
36
37  // VALUE_SYMTAB_BLOCK abbrev id's.
38  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
39  VST_ENTRY_7_ABBREV,
40  VST_ENTRY_6_ABBREV,
41  VST_BBENTRY_6_ABBREV,
42
43  // CONSTANTS_BLOCK abbrev id's.
44  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
45  CONSTANTS_INTEGER_ABBREV,
46  CONSTANTS_CE_CAST_Abbrev,
47  CONSTANTS_NULL_Abbrev,
48
49  // FUNCTION_BLOCK abbrev id's.
50  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
51  FUNCTION_INST_BINOP_ABBREV,
52  FUNCTION_INST_BINOP_FLAGS_ABBREV,
53  FUNCTION_INST_CAST_ABBREV,
54  FUNCTION_INST_RET_VOID_ABBREV,
55  FUNCTION_INST_RET_VAL_ABBREV,
56  FUNCTION_INST_UNREACHABLE_ABBREV
57};
58
59
60static unsigned GetEncodedCastOpcode(unsigned Opcode) {
61  switch (Opcode) {
62  default: llvm_unreachable("Unknown cast instruction!");
63  case Instruction::Trunc   : return bitc::CAST_TRUNC;
64  case Instruction::ZExt    : return bitc::CAST_ZEXT;
65  case Instruction::SExt    : return bitc::CAST_SEXT;
66  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
67  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
68  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
69  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
70  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
71  case Instruction::FPExt   : return bitc::CAST_FPEXT;
72  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
73  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
74  case Instruction::BitCast : return bitc::CAST_BITCAST;
75  }
76}
77
78static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
79  switch (Opcode) {
80  default: llvm_unreachable("Unknown binary instruction!");
81  case Instruction::Add:
82  case Instruction::FAdd: return bitc::BINOP_ADD;
83  case Instruction::Sub:
84  case Instruction::FSub: return bitc::BINOP_SUB;
85  case Instruction::Mul:
86  case Instruction::FMul: return bitc::BINOP_MUL;
87  case Instruction::UDiv: return bitc::BINOP_UDIV;
88  case Instruction::FDiv:
89  case Instruction::SDiv: return bitc::BINOP_SDIV;
90  case Instruction::URem: return bitc::BINOP_UREM;
91  case Instruction::FRem:
92  case Instruction::SRem: return bitc::BINOP_SREM;
93  case Instruction::Shl:  return bitc::BINOP_SHL;
94  case Instruction::LShr: return bitc::BINOP_LSHR;
95  case Instruction::AShr: return bitc::BINOP_ASHR;
96  case Instruction::And:  return bitc::BINOP_AND;
97  case Instruction::Or:   return bitc::BINOP_OR;
98  case Instruction::Xor:  return bitc::BINOP_XOR;
99  }
100}
101
102
103
104static void WriteStringRecord(unsigned Code, const std::string &Str,
105                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
106  SmallVector<unsigned, 64> Vals;
107
108  // Code: [strchar x N]
109  for (unsigned i = 0, e = Str.size(); i != e; ++i)
110    Vals.push_back(Str[i]);
111
112  // Emit the finished record.
113  Stream.EmitRecord(Code, Vals, AbbrevToUse);
114}
115
116// Emit information about parameter attributes.
117static void WriteAttributeTable(const ValueEnumerator &VE,
118                                BitstreamWriter &Stream) {
119  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
120  if (Attrs.empty()) return;
121
122  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
123
124  SmallVector<uint64_t, 64> Record;
125  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
126    const AttrListPtr &A = Attrs[i];
127    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
128      const AttributeWithIndex &PAWI = A.getSlot(i);
129      Record.push_back(PAWI.Index);
130
131      // FIXME: remove in LLVM 3.0
132      // Store the alignment in the bitcode as a 16-bit raw value instead of a
133      // 5-bit log2 encoded value. Shift the bits above the alignment up by
134      // 11 bits.
135      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
136      if (PAWI.Attrs & Attribute::Alignment)
137        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
138      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
139
140      Record.push_back(FauxAttr);
141    }
142
143    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
144    Record.clear();
145  }
146
147  Stream.ExitBlock();
148}
149
150/// WriteTypeTable - Write out the type table for a module.
151static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
152  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
153
154  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
155  SmallVector<uint64_t, 64> TypeVals;
156
157  // Abbrev for TYPE_CODE_POINTER.
158  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
159  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
160  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
161                            Log2_32_Ceil(VE.getTypes().size()+1)));
162  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
163  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
164
165  // Abbrev for TYPE_CODE_FUNCTION.
166  Abbv = new BitCodeAbbrev();
167  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
168  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
169  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
171  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
172                            Log2_32_Ceil(VE.getTypes().size()+1)));
173  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
174
175  // Abbrev for TYPE_CODE_STRUCT.
176  Abbv = new BitCodeAbbrev();
177  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
178  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
179  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
181                            Log2_32_Ceil(VE.getTypes().size()+1)));
182  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
183
184  // Abbrev for TYPE_CODE_ARRAY.
185  Abbv = new BitCodeAbbrev();
186  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
187  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
188  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
189                            Log2_32_Ceil(VE.getTypes().size()+1)));
190  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
191
192  // Emit an entry count so the reader can reserve space.
193  TypeVals.push_back(TypeList.size());
194  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
195  TypeVals.clear();
196
197  // Loop over all of the types, emitting each in turn.
198  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
199    const Type *T = TypeList[i].first;
200    int AbbrevToUse = 0;
201    unsigned Code = 0;
202
203    switch (T->getTypeID()) {
204    default: llvm_unreachable("Unknown type!");
205    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
206    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
207    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
208    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
209    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
210    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
211    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
212    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
213    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
214    case Type::IntegerTyID:
215      // INTEGER: [width]
216      Code = bitc::TYPE_CODE_INTEGER;
217      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
218      break;
219    case Type::PointerTyID: {
220      const PointerType *PTy = cast<PointerType>(T);
221      // POINTER: [pointee type, address space]
222      Code = bitc::TYPE_CODE_POINTER;
223      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
224      unsigned AddressSpace = PTy->getAddressSpace();
225      TypeVals.push_back(AddressSpace);
226      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
227      break;
228    }
229    case Type::FunctionTyID: {
230      const FunctionType *FT = cast<FunctionType>(T);
231      // FUNCTION: [isvararg, attrid, retty, paramty x N]
232      Code = bitc::TYPE_CODE_FUNCTION;
233      TypeVals.push_back(FT->isVarArg());
234      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
235      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
236      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
237        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
238      AbbrevToUse = FunctionAbbrev;
239      break;
240    }
241    case Type::StructTyID: {
242      const StructType *ST = cast<StructType>(T);
243      // STRUCT: [ispacked, eltty x N]
244      Code = bitc::TYPE_CODE_STRUCT;
245      TypeVals.push_back(ST->isPacked());
246      // Output all of the element types.
247      for (StructType::element_iterator I = ST->element_begin(),
248           E = ST->element_end(); I != E; ++I)
249        TypeVals.push_back(VE.getTypeID(*I));
250      AbbrevToUse = StructAbbrev;
251      break;
252    }
253    case Type::ArrayTyID: {
254      const ArrayType *AT = cast<ArrayType>(T);
255      // ARRAY: [numelts, eltty]
256      Code = bitc::TYPE_CODE_ARRAY;
257      TypeVals.push_back(AT->getNumElements());
258      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
259      AbbrevToUse = ArrayAbbrev;
260      break;
261    }
262    case Type::VectorTyID: {
263      const VectorType *VT = cast<VectorType>(T);
264      // VECTOR [numelts, eltty]
265      Code = bitc::TYPE_CODE_VECTOR;
266      TypeVals.push_back(VT->getNumElements());
267      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
268      break;
269    }
270    }
271
272    // Emit the finished record.
273    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
274    TypeVals.clear();
275  }
276
277  Stream.ExitBlock();
278}
279
280static unsigned getEncodedLinkage(const GlobalValue *GV) {
281  switch (GV->getLinkage()) {
282  default: llvm_unreachable("Invalid linkage!");
283  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
284  case GlobalValue::ExternalLinkage:            return 0;
285  case GlobalValue::WeakAnyLinkage:             return 1;
286  case GlobalValue::AppendingLinkage:           return 2;
287  case GlobalValue::InternalLinkage:            return 3;
288  case GlobalValue::LinkOnceAnyLinkage:         return 4;
289  case GlobalValue::DLLImportLinkage:           return 5;
290  case GlobalValue::DLLExportLinkage:           return 6;
291  case GlobalValue::ExternalWeakLinkage:        return 7;
292  case GlobalValue::CommonLinkage:              return 8;
293  case GlobalValue::PrivateLinkage:             return 9;
294  case GlobalValue::WeakODRLinkage:             return 10;
295  case GlobalValue::LinkOnceODRLinkage:         return 11;
296  case GlobalValue::AvailableExternallyLinkage: return 12;
297  case GlobalValue::LinkerPrivateLinkage:       return 13;
298  }
299}
300
301static unsigned getEncodedVisibility(const GlobalValue *GV) {
302  switch (GV->getVisibility()) {
303  default: llvm_unreachable("Invalid visibility!");
304  case GlobalValue::DefaultVisibility:   return 0;
305  case GlobalValue::HiddenVisibility:    return 1;
306  case GlobalValue::ProtectedVisibility: return 2;
307  }
308}
309
310// Emit top-level description of module, including target triple, inline asm,
311// descriptors for global variables, and function prototype info.
312static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
313                            BitstreamWriter &Stream) {
314  // Emit the list of dependent libraries for the Module.
315  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
316    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
317
318  // Emit various pieces of data attached to a module.
319  if (!M->getTargetTriple().empty())
320    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
321                      0/*TODO*/, Stream);
322  if (!M->getDataLayout().empty())
323    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
324                      0/*TODO*/, Stream);
325  if (!M->getModuleInlineAsm().empty())
326    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
327                      0/*TODO*/, Stream);
328
329  // Emit information about sections and GC, computing how many there are. Also
330  // compute the maximum alignment value.
331  std::map<std::string, unsigned> SectionMap;
332  std::map<std::string, unsigned> GCMap;
333  unsigned MaxAlignment = 0;
334  unsigned MaxGlobalType = 0;
335  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
336       GV != E; ++GV) {
337    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
338    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
339
340    if (!GV->hasSection()) continue;
341    // Give section names unique ID's.
342    unsigned &Entry = SectionMap[GV->getSection()];
343    if (Entry != 0) continue;
344    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
345                      0/*TODO*/, Stream);
346    Entry = SectionMap.size();
347  }
348  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
349    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
350    if (F->hasSection()) {
351      // Give section names unique ID's.
352      unsigned &Entry = SectionMap[F->getSection()];
353      if (!Entry) {
354        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
355                          0/*TODO*/, Stream);
356        Entry = SectionMap.size();
357      }
358    }
359    if (F->hasGC()) {
360      // Same for GC names.
361      unsigned &Entry = GCMap[F->getGC()];
362      if (!Entry) {
363        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
364                          0/*TODO*/, Stream);
365        Entry = GCMap.size();
366      }
367    }
368  }
369
370  // Emit abbrev for globals, now that we know # sections and max alignment.
371  unsigned SimpleGVarAbbrev = 0;
372  if (!M->global_empty()) {
373    // Add an abbrev for common globals with no visibility or thread localness.
374    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
375    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
376    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
377                              Log2_32_Ceil(MaxGlobalType+1)));
378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
379    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
380    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
381    if (MaxAlignment == 0)                                      // Alignment.
382      Abbv->Add(BitCodeAbbrevOp(0));
383    else {
384      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
385      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
386                               Log2_32_Ceil(MaxEncAlignment+1)));
387    }
388    if (SectionMap.empty())                                    // Section.
389      Abbv->Add(BitCodeAbbrevOp(0));
390    else
391      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
392                               Log2_32_Ceil(SectionMap.size()+1)));
393    // Don't bother emitting vis + thread local.
394    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
395  }
396
397  // Emit the global variable information.
398  SmallVector<unsigned, 64> Vals;
399  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
400       GV != E; ++GV) {
401    unsigned AbbrevToUse = 0;
402
403    // GLOBALVAR: [type, isconst, initid,
404    //             linkage, alignment, section, visibility, threadlocal]
405    Vals.push_back(VE.getTypeID(GV->getType()));
406    Vals.push_back(GV->isConstant());
407    Vals.push_back(GV->isDeclaration() ? 0 :
408                   (VE.getValueID(GV->getInitializer()) + 1));
409    Vals.push_back(getEncodedLinkage(GV));
410    Vals.push_back(Log2_32(GV->getAlignment())+1);
411    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
412    if (GV->isThreadLocal() ||
413        GV->getVisibility() != GlobalValue::DefaultVisibility) {
414      Vals.push_back(getEncodedVisibility(GV));
415      Vals.push_back(GV->isThreadLocal());
416    } else {
417      AbbrevToUse = SimpleGVarAbbrev;
418    }
419
420    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
421    Vals.clear();
422  }
423
424  // Emit the function proto information.
425  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
426    // FUNCTION:  [type, callingconv, isproto, paramattr,
427    //             linkage, alignment, section, visibility, gc]
428    Vals.push_back(VE.getTypeID(F->getType()));
429    Vals.push_back(F->getCallingConv());
430    Vals.push_back(F->isDeclaration());
431    Vals.push_back(getEncodedLinkage(F));
432    Vals.push_back(VE.getAttributeID(F->getAttributes()));
433    Vals.push_back(Log2_32(F->getAlignment())+1);
434    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
435    Vals.push_back(getEncodedVisibility(F));
436    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
437
438    unsigned AbbrevToUse = 0;
439    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
440    Vals.clear();
441  }
442
443
444  // Emit the alias information.
445  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
446       AI != E; ++AI) {
447    Vals.push_back(VE.getTypeID(AI->getType()));
448    Vals.push_back(VE.getValueID(AI->getAliasee()));
449    Vals.push_back(getEncodedLinkage(AI));
450    Vals.push_back(getEncodedVisibility(AI));
451    unsigned AbbrevToUse = 0;
452    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
453    Vals.clear();
454  }
455}
456
457static uint64_t GetOptimizationFlags(const Value *V) {
458  uint64_t Flags = 0;
459
460  if (const OverflowingBinaryOperator *OBO =
461        dyn_cast<OverflowingBinaryOperator>(V)) {
462    if (OBO->hasNoSignedWrap())
463      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
464    if (OBO->hasNoUnsignedWrap())
465      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
466  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
467    if (Div->isExact())
468      Flags |= 1 << bitc::SDIV_EXACT;
469  }
470
471  return Flags;
472}
473
474static void WriteMDNode(const MDNode *N,
475                        const ValueEnumerator &VE,
476                        BitstreamWriter &Stream,
477                        SmallVector<uint64_t, 64> &Record) {
478  for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
479    if (N->getElement(i)) {
480      Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
481      Record.push_back(VE.getValueID(N->getElement(i)));
482    } else {
483      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
484      Record.push_back(0);
485    }
486  }
487  Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
488  Record.clear();
489}
490
491static void WriteModuleMetadata(const ValueEnumerator &VE,
492                                BitstreamWriter &Stream) {
493  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
494  bool StartedMetadataBlock = false;
495  unsigned MDSAbbrev = 0;
496  SmallVector<uint64_t, 64> Record;
497  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
498
499    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
500      if (!StartedMetadataBlock) {
501        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
502        StartedMetadataBlock = true;
503      }
504      WriteMDNode(N, VE, Stream, Record);
505    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
506      if (!StartedMetadataBlock)  {
507        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
508
509        // Abbrev for METADATA_STRING.
510        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
511        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
512        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
513        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
514        MDSAbbrev = Stream.EmitAbbrev(Abbv);
515        StartedMetadataBlock = true;
516      }
517
518      // Code: [strchar x N]
519      Record.append(MDS->begin(), MDS->end());
520
521      // Emit the finished record.
522      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
523      Record.clear();
524    } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
525      if (!StartedMetadataBlock)  {
526        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
527        StartedMetadataBlock = true;
528      }
529
530      // Write name.
531      std::string Str = NMD->getNameStr();
532      const char *StrBegin = Str.c_str();
533      for (unsigned i = 0, e = Str.length(); i != e; ++i)
534        Record.push_back(StrBegin[i]);
535      Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
536      Record.clear();
537
538      // Write named metadata elements.
539      for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
540        if (NMD->getElement(i))
541          Record.push_back(VE.getValueID(NMD->getElement(i)));
542        else
543          Record.push_back(0);
544      }
545      Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
546      Record.clear();
547    }
548  }
549
550  if (StartedMetadataBlock)
551    Stream.ExitBlock();
552}
553
554static void WriteMetadataAttachment(const Function &F,
555                                    const ValueEnumerator &VE,
556                                    BitstreamWriter &Stream) {
557  bool StartedMetadataBlock = false;
558  SmallVector<uint64_t, 64> Record;
559
560  // Write metadata attachments
561  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
562  SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
563
564  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
565    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
566         I != E; ++I) {
567      MDs.clear();
568      I->getAllMetadata(MDs);
569
570      // If no metadata, ignore instruction.
571      if (MDs.empty()) continue;
572
573      Record.push_back(VE.getInstructionID(I));
574
575      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
576        Record.push_back(MDs[i].first);
577        Record.push_back(VE.getValueID(MDs[i].second));
578      }
579      if (!StartedMetadataBlock)  {
580        Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
581        StartedMetadataBlock = true;
582      }
583      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
584      Record.clear();
585    }
586
587  if (StartedMetadataBlock)
588    Stream.ExitBlock();
589}
590
591static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
592  SmallVector<uint64_t, 64> Record;
593
594  // Write metadata kinds
595  // METADATA_KIND - [n x [id, name]]
596  SmallVector<StringRef, 4> Names;
597  M->getMDKindNames(Names);
598
599  assert(Names[0] == "" && "MDKind #0 is invalid");
600  if (Names.size() == 1) return;
601
602  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
603
604  for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
605    Record.push_back(MDKindID);
606    StringRef KName = Names[MDKindID];
607    Record.append(KName.begin(), KName.end());
608
609    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
610    Record.clear();
611  }
612
613  Stream.ExitBlock();
614}
615
616static void WriteConstants(unsigned FirstVal, unsigned LastVal,
617                           const ValueEnumerator &VE,
618                           BitstreamWriter &Stream, bool isGlobal) {
619  if (FirstVal == LastVal) return;
620
621  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
622
623  unsigned AggregateAbbrev = 0;
624  unsigned String8Abbrev = 0;
625  unsigned CString7Abbrev = 0;
626  unsigned CString6Abbrev = 0;
627  // If this is a constant pool for the module, emit module-specific abbrevs.
628  if (isGlobal) {
629    // Abbrev for CST_CODE_AGGREGATE.
630    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
631    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
632    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
633    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
634    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
635
636    // Abbrev for CST_CODE_STRING.
637    Abbv = new BitCodeAbbrev();
638    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
639    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
640    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
641    String8Abbrev = Stream.EmitAbbrev(Abbv);
642    // Abbrev for CST_CODE_CSTRING.
643    Abbv = new BitCodeAbbrev();
644    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
645    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
646    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
647    CString7Abbrev = Stream.EmitAbbrev(Abbv);
648    // Abbrev for CST_CODE_CSTRING.
649    Abbv = new BitCodeAbbrev();
650    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
651    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
652    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
653    CString6Abbrev = Stream.EmitAbbrev(Abbv);
654  }
655
656  SmallVector<uint64_t, 64> Record;
657
658  const ValueEnumerator::ValueList &Vals = VE.getValues();
659  const Type *LastTy = 0;
660  for (unsigned i = FirstVal; i != LastVal; ++i) {
661    const Value *V = Vals[i].first;
662    // If we need to switch types, do so now.
663    if (V->getType() != LastTy) {
664      LastTy = V->getType();
665      Record.push_back(VE.getTypeID(LastTy));
666      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
667                        CONSTANTS_SETTYPE_ABBREV);
668      Record.clear();
669    }
670
671    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
672      Record.push_back(unsigned(IA->hasSideEffects()) |
673                       unsigned(IA->isAlignStack()) << 1);
674
675      // Add the asm string.
676      const std::string &AsmStr = IA->getAsmString();
677      Record.push_back(AsmStr.size());
678      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
679        Record.push_back(AsmStr[i]);
680
681      // Add the constraint string.
682      const std::string &ConstraintStr = IA->getConstraintString();
683      Record.push_back(ConstraintStr.size());
684      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
685        Record.push_back(ConstraintStr[i]);
686      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
687      Record.clear();
688      continue;
689    }
690    const Constant *C = cast<Constant>(V);
691    unsigned Code = -1U;
692    unsigned AbbrevToUse = 0;
693    if (C->isNullValue()) {
694      Code = bitc::CST_CODE_NULL;
695    } else if (isa<UndefValue>(C)) {
696      Code = bitc::CST_CODE_UNDEF;
697    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
698      if (IV->getBitWidth() <= 64) {
699        int64_t V = IV->getSExtValue();
700        if (V >= 0)
701          Record.push_back(V << 1);
702        else
703          Record.push_back((-V << 1) | 1);
704        Code = bitc::CST_CODE_INTEGER;
705        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
706      } else {                             // Wide integers, > 64 bits in size.
707        // We have an arbitrary precision integer value to write whose
708        // bit width is > 64. However, in canonical unsigned integer
709        // format it is likely that the high bits are going to be zero.
710        // So, we only write the number of active words.
711        unsigned NWords = IV->getValue().getActiveWords();
712        const uint64_t *RawWords = IV->getValue().getRawData();
713        for (unsigned i = 0; i != NWords; ++i) {
714          int64_t V = RawWords[i];
715          if (V >= 0)
716            Record.push_back(V << 1);
717          else
718            Record.push_back((-V << 1) | 1);
719        }
720        Code = bitc::CST_CODE_WIDE_INTEGER;
721      }
722    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
723      Code = bitc::CST_CODE_FLOAT;
724      const Type *Ty = CFP->getType();
725      if (Ty->isFloatTy() || Ty->isDoubleTy()) {
726        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
727      } else if (Ty->isX86_FP80Ty()) {
728        // api needed to prevent premature destruction
729        // bits are not in the same order as a normal i80 APInt, compensate.
730        APInt api = CFP->getValueAPF().bitcastToAPInt();
731        const uint64_t *p = api.getRawData();
732        Record.push_back((p[1] << 48) | (p[0] >> 16));
733        Record.push_back(p[0] & 0xffffLL);
734      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
735        APInt api = CFP->getValueAPF().bitcastToAPInt();
736        const uint64_t *p = api.getRawData();
737        Record.push_back(p[0]);
738        Record.push_back(p[1]);
739      } else {
740        assert (0 && "Unknown FP type!");
741      }
742    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
743      const ConstantArray *CA = cast<ConstantArray>(C);
744      // Emit constant strings specially.
745      unsigned NumOps = CA->getNumOperands();
746      // If this is a null-terminated string, use the denser CSTRING encoding.
747      if (CA->getOperand(NumOps-1)->isNullValue()) {
748        Code = bitc::CST_CODE_CSTRING;
749        --NumOps;  // Don't encode the null, which isn't allowed by char6.
750      } else {
751        Code = bitc::CST_CODE_STRING;
752        AbbrevToUse = String8Abbrev;
753      }
754      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
755      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
756      for (unsigned i = 0; i != NumOps; ++i) {
757        unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
758        Record.push_back(V);
759        isCStr7 &= (V & 128) == 0;
760        if (isCStrChar6)
761          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
762      }
763
764      if (isCStrChar6)
765        AbbrevToUse = CString6Abbrev;
766      else if (isCStr7)
767        AbbrevToUse = CString7Abbrev;
768    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
769               isa<ConstantVector>(V)) {
770      Code = bitc::CST_CODE_AGGREGATE;
771      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
772        Record.push_back(VE.getValueID(C->getOperand(i)));
773      AbbrevToUse = AggregateAbbrev;
774    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
775      switch (CE->getOpcode()) {
776      default:
777        if (Instruction::isCast(CE->getOpcode())) {
778          Code = bitc::CST_CODE_CE_CAST;
779          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
780          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
781          Record.push_back(VE.getValueID(C->getOperand(0)));
782          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
783        } else {
784          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
785          Code = bitc::CST_CODE_CE_BINOP;
786          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
787          Record.push_back(VE.getValueID(C->getOperand(0)));
788          Record.push_back(VE.getValueID(C->getOperand(1)));
789          uint64_t Flags = GetOptimizationFlags(CE);
790          if (Flags != 0)
791            Record.push_back(Flags);
792        }
793        break;
794      case Instruction::GetElementPtr:
795        Code = bitc::CST_CODE_CE_GEP;
796        if (cast<GEPOperator>(C)->isInBounds())
797          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
798        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
799          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
800          Record.push_back(VE.getValueID(C->getOperand(i)));
801        }
802        break;
803      case Instruction::Select:
804        Code = bitc::CST_CODE_CE_SELECT;
805        Record.push_back(VE.getValueID(C->getOperand(0)));
806        Record.push_back(VE.getValueID(C->getOperand(1)));
807        Record.push_back(VE.getValueID(C->getOperand(2)));
808        break;
809      case Instruction::ExtractElement:
810        Code = bitc::CST_CODE_CE_EXTRACTELT;
811        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
812        Record.push_back(VE.getValueID(C->getOperand(0)));
813        Record.push_back(VE.getValueID(C->getOperand(1)));
814        break;
815      case Instruction::InsertElement:
816        Code = bitc::CST_CODE_CE_INSERTELT;
817        Record.push_back(VE.getValueID(C->getOperand(0)));
818        Record.push_back(VE.getValueID(C->getOperand(1)));
819        Record.push_back(VE.getValueID(C->getOperand(2)));
820        break;
821      case Instruction::ShuffleVector:
822        // If the return type and argument types are the same, this is a
823        // standard shufflevector instruction.  If the types are different,
824        // then the shuffle is widening or truncating the input vectors, and
825        // the argument type must also be encoded.
826        if (C->getType() == C->getOperand(0)->getType()) {
827          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
828        } else {
829          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
830          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
831        }
832        Record.push_back(VE.getValueID(C->getOperand(0)));
833        Record.push_back(VE.getValueID(C->getOperand(1)));
834        Record.push_back(VE.getValueID(C->getOperand(2)));
835        break;
836      case Instruction::ICmp:
837      case Instruction::FCmp:
838        Code = bitc::CST_CODE_CE_CMP;
839        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
840        Record.push_back(VE.getValueID(C->getOperand(0)));
841        Record.push_back(VE.getValueID(C->getOperand(1)));
842        Record.push_back(CE->getPredicate());
843        break;
844      }
845    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
846      assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
847             "Malformed blockaddress");
848      Code = bitc::CST_CODE_BLOCKADDRESS;
849      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
850      Record.push_back(VE.getValueID(BA->getFunction()));
851      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
852    } else {
853      llvm_unreachable("Unknown constant!");
854    }
855    Stream.EmitRecord(Code, Record, AbbrevToUse);
856    Record.clear();
857  }
858
859  Stream.ExitBlock();
860}
861
862static void WriteModuleConstants(const ValueEnumerator &VE,
863                                 BitstreamWriter &Stream) {
864  const ValueEnumerator::ValueList &Vals = VE.getValues();
865
866  // Find the first constant to emit, which is the first non-globalvalue value.
867  // We know globalvalues have been emitted by WriteModuleInfo.
868  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
869    if (!isa<GlobalValue>(Vals[i].first)) {
870      WriteConstants(i, Vals.size(), VE, Stream, true);
871      return;
872    }
873  }
874}
875
876/// PushValueAndType - The file has to encode both the value and type id for
877/// many values, because we need to know what type to create for forward
878/// references.  However, most operands are not forward references, so this type
879/// field is not needed.
880///
881/// This function adds V's value ID to Vals.  If the value ID is higher than the
882/// instruction ID, then it is a forward reference, and it also includes the
883/// type ID.
884static bool PushValueAndType(const Value *V, unsigned InstID,
885                             SmallVector<unsigned, 64> &Vals,
886                             ValueEnumerator &VE) {
887  unsigned ValID = VE.getValueID(V);
888  Vals.push_back(ValID);
889  if (ValID >= InstID) {
890    Vals.push_back(VE.getTypeID(V->getType()));
891    return true;
892  }
893  return false;
894}
895
896/// WriteInstruction - Emit an instruction to the specified stream.
897static void WriteInstruction(const Instruction &I, unsigned InstID,
898                             ValueEnumerator &VE, BitstreamWriter &Stream,
899                             SmallVector<unsigned, 64> &Vals) {
900  unsigned Code = 0;
901  unsigned AbbrevToUse = 0;
902  VE.setInstructionID(&I);
903  switch (I.getOpcode()) {
904  default:
905    if (Instruction::isCast(I.getOpcode())) {
906      Code = bitc::FUNC_CODE_INST_CAST;
907      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
908        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
909      Vals.push_back(VE.getTypeID(I.getType()));
910      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
911    } else {
912      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
913      Code = bitc::FUNC_CODE_INST_BINOP;
914      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
915        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
916      Vals.push_back(VE.getValueID(I.getOperand(1)));
917      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
918      uint64_t Flags = GetOptimizationFlags(&I);
919      if (Flags != 0) {
920        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
921          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
922        Vals.push_back(Flags);
923      }
924    }
925    break;
926
927  case Instruction::GetElementPtr:
928    Code = bitc::FUNC_CODE_INST_GEP;
929    if (cast<GEPOperator>(&I)->isInBounds())
930      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
931    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
932      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
933    break;
934  case Instruction::ExtractValue: {
935    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
936    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
937    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
938    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
939      Vals.push_back(*i);
940    break;
941  }
942  case Instruction::InsertValue: {
943    Code = bitc::FUNC_CODE_INST_INSERTVAL;
944    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
945    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
946    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
947    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
948      Vals.push_back(*i);
949    break;
950  }
951  case Instruction::Select:
952    Code = bitc::FUNC_CODE_INST_VSELECT;
953    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
954    Vals.push_back(VE.getValueID(I.getOperand(2)));
955    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
956    break;
957  case Instruction::ExtractElement:
958    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
959    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
960    Vals.push_back(VE.getValueID(I.getOperand(1)));
961    break;
962  case Instruction::InsertElement:
963    Code = bitc::FUNC_CODE_INST_INSERTELT;
964    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
965    Vals.push_back(VE.getValueID(I.getOperand(1)));
966    Vals.push_back(VE.getValueID(I.getOperand(2)));
967    break;
968  case Instruction::ShuffleVector:
969    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
970    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
971    Vals.push_back(VE.getValueID(I.getOperand(1)));
972    Vals.push_back(VE.getValueID(I.getOperand(2)));
973    break;
974  case Instruction::ICmp:
975  case Instruction::FCmp:
976    // compare returning Int1Ty or vector of Int1Ty
977    Code = bitc::FUNC_CODE_INST_CMP2;
978    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
979    Vals.push_back(VE.getValueID(I.getOperand(1)));
980    Vals.push_back(cast<CmpInst>(I).getPredicate());
981    break;
982
983  case Instruction::Ret:
984    {
985      Code = bitc::FUNC_CODE_INST_RET;
986      unsigned NumOperands = I.getNumOperands();
987      if (NumOperands == 0)
988        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
989      else if (NumOperands == 1) {
990        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
991          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
992      } else {
993        for (unsigned i = 0, e = NumOperands; i != e; ++i)
994          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
995      }
996    }
997    break;
998  case Instruction::Br:
999    {
1000      Code = bitc::FUNC_CODE_INST_BR;
1001      BranchInst &II = cast<BranchInst>(I);
1002      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1003      if (II.isConditional()) {
1004        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1005        Vals.push_back(VE.getValueID(II.getCondition()));
1006      }
1007    }
1008    break;
1009  case Instruction::Switch:
1010    Code = bitc::FUNC_CODE_INST_SWITCH;
1011    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1012    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1013      Vals.push_back(VE.getValueID(I.getOperand(i)));
1014    break;
1015  case Instruction::IndirectBr:
1016    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1017    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1018    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1019      Vals.push_back(VE.getValueID(I.getOperand(i)));
1020    break;
1021
1022  case Instruction::Invoke: {
1023    const InvokeInst *II = cast<InvokeInst>(&I);
1024    const Value *Callee(II->getCalledValue());
1025    const PointerType *PTy = cast<PointerType>(Callee->getType());
1026    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1027    Code = bitc::FUNC_CODE_INST_INVOKE;
1028
1029    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1030    Vals.push_back(II->getCallingConv());
1031    Vals.push_back(VE.getValueID(II->getNormalDest()));
1032    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1033    PushValueAndType(Callee, InstID, Vals, VE);
1034
1035    // Emit value #'s for the fixed parameters.
1036    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1037      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1038
1039    // Emit type/value pairs for varargs params.
1040    if (FTy->isVarArg()) {
1041      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1042           i != e; ++i)
1043        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1044    }
1045    break;
1046  }
1047  case Instruction::Unwind:
1048    Code = bitc::FUNC_CODE_INST_UNWIND;
1049    break;
1050  case Instruction::Unreachable:
1051    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1052    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1053    break;
1054
1055  case Instruction::PHI:
1056    Code = bitc::FUNC_CODE_INST_PHI;
1057    Vals.push_back(VE.getTypeID(I.getType()));
1058    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1059      Vals.push_back(VE.getValueID(I.getOperand(i)));
1060    break;
1061
1062  case Instruction::Alloca:
1063    Code = bitc::FUNC_CODE_INST_ALLOCA;
1064    Vals.push_back(VE.getTypeID(I.getType()));
1065    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1066    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1067    break;
1068
1069  case Instruction::Load:
1070    Code = bitc::FUNC_CODE_INST_LOAD;
1071    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1072      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1073
1074    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1075    Vals.push_back(cast<LoadInst>(I).isVolatile());
1076    break;
1077  case Instruction::Store:
1078    Code = bitc::FUNC_CODE_INST_STORE2;
1079    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1080    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1081    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1082    Vals.push_back(cast<StoreInst>(I).isVolatile());
1083    break;
1084  case Instruction::Call: {
1085    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1086    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1087
1088    Code = bitc::FUNC_CODE_INST_CALL;
1089
1090    const CallInst *CI = cast<CallInst>(&I);
1091    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1092    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1093    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1094
1095    // Emit value #'s for the fixed parameters.
1096    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1097      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1098
1099    // Emit type/value pairs for varargs params.
1100    if (FTy->isVarArg()) {
1101      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1102      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1103           i != e; ++i)
1104        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1105    }
1106    break;
1107  }
1108  case Instruction::VAArg:
1109    Code = bitc::FUNC_CODE_INST_VAARG;
1110    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1111    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1112    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1113    break;
1114  }
1115
1116  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1117  Vals.clear();
1118}
1119
1120// Emit names for globals/functions etc.
1121static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1122                                  const ValueEnumerator &VE,
1123                                  BitstreamWriter &Stream) {
1124  if (VST.empty()) return;
1125  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1126
1127  // FIXME: Set up the abbrev, we know how many values there are!
1128  // FIXME: We know if the type names can use 7-bit ascii.
1129  SmallVector<unsigned, 64> NameVals;
1130
1131  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1132       SI != SE; ++SI) {
1133
1134    const ValueName &Name = *SI;
1135
1136    // Figure out the encoding to use for the name.
1137    bool is7Bit = true;
1138    bool isChar6 = true;
1139    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1140         C != E; ++C) {
1141      if (isChar6)
1142        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1143      if ((unsigned char)*C & 128) {
1144        is7Bit = false;
1145        break;  // don't bother scanning the rest.
1146      }
1147    }
1148
1149    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1150
1151    // VST_ENTRY:   [valueid, namechar x N]
1152    // VST_BBENTRY: [bbid, namechar x N]
1153    unsigned Code;
1154    if (isa<BasicBlock>(SI->getValue())) {
1155      Code = bitc::VST_CODE_BBENTRY;
1156      if (isChar6)
1157        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1158    } else {
1159      Code = bitc::VST_CODE_ENTRY;
1160      if (isChar6)
1161        AbbrevToUse = VST_ENTRY_6_ABBREV;
1162      else if (is7Bit)
1163        AbbrevToUse = VST_ENTRY_7_ABBREV;
1164    }
1165
1166    NameVals.push_back(VE.getValueID(SI->getValue()));
1167    for (const char *P = Name.getKeyData(),
1168         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1169      NameVals.push_back((unsigned char)*P);
1170
1171    // Emit the finished record.
1172    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1173    NameVals.clear();
1174  }
1175  Stream.ExitBlock();
1176}
1177
1178/// WriteFunction - Emit a function body to the module stream.
1179static void WriteFunction(const Function &F, ValueEnumerator &VE,
1180                          BitstreamWriter &Stream) {
1181  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1182  VE.incorporateFunction(F);
1183
1184  SmallVector<unsigned, 64> Vals;
1185
1186  // Emit the number of basic blocks, so the reader can create them ahead of
1187  // time.
1188  Vals.push_back(VE.getBasicBlocks().size());
1189  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1190  Vals.clear();
1191
1192  // If there are function-local constants, emit them now.
1193  unsigned CstStart, CstEnd;
1194  VE.getFunctionConstantRange(CstStart, CstEnd);
1195  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1196
1197  // Keep a running idea of what the instruction ID is.
1198  unsigned InstID = CstEnd;
1199
1200  // Finally, emit all the instructions, in order.
1201  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1202    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1203         I != E; ++I) {
1204      WriteInstruction(*I, InstID, VE, Stream, Vals);
1205      if (!I->getType()->isVoidTy())
1206        ++InstID;
1207    }
1208
1209  // Emit names for all the instructions etc.
1210  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1211
1212  WriteMetadataAttachment(F, VE, Stream);
1213  VE.purgeFunction();
1214  Stream.ExitBlock();
1215}
1216
1217/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1218static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1219                                 const ValueEnumerator &VE,
1220                                 BitstreamWriter &Stream) {
1221  if (TST.empty()) return;
1222
1223  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1224
1225  // 7-bit fixed width VST_CODE_ENTRY strings.
1226  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1227  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1228  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1229                            Log2_32_Ceil(VE.getTypes().size()+1)));
1230  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1231  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1232  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1233
1234  SmallVector<unsigned, 64> NameVals;
1235
1236  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1237       TI != TE; ++TI) {
1238    // TST_ENTRY: [typeid, namechar x N]
1239    NameVals.push_back(VE.getTypeID(TI->second));
1240
1241    const std::string &Str = TI->first;
1242    bool is7Bit = true;
1243    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1244      NameVals.push_back((unsigned char)Str[i]);
1245      if (Str[i] & 128)
1246        is7Bit = false;
1247    }
1248
1249    // Emit the finished record.
1250    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1251    NameVals.clear();
1252  }
1253
1254  Stream.ExitBlock();
1255}
1256
1257// Emit blockinfo, which defines the standard abbreviations etc.
1258static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1259  // We only want to emit block info records for blocks that have multiple
1260  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1261  // blocks can defined their abbrevs inline.
1262  Stream.EnterBlockInfoBlock(2);
1263
1264  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1265    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1266    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1267    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1268    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1269    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1270    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1271                                   Abbv) != VST_ENTRY_8_ABBREV)
1272      llvm_unreachable("Unexpected abbrev ordering!");
1273  }
1274
1275  { // 7-bit fixed width VST_ENTRY strings.
1276    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1277    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1278    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1279    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1280    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1281    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1282                                   Abbv) != VST_ENTRY_7_ABBREV)
1283      llvm_unreachable("Unexpected abbrev ordering!");
1284  }
1285  { // 6-bit char6 VST_ENTRY strings.
1286    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1287    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1288    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1289    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1290    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1291    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1292                                   Abbv) != VST_ENTRY_6_ABBREV)
1293      llvm_unreachable("Unexpected abbrev ordering!");
1294  }
1295  { // 6-bit char6 VST_BBENTRY strings.
1296    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1297    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1298    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1299    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1300    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1301    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1302                                   Abbv) != VST_BBENTRY_6_ABBREV)
1303      llvm_unreachable("Unexpected abbrev ordering!");
1304  }
1305
1306
1307
1308  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1309    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1310    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1311    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1312                              Log2_32_Ceil(VE.getTypes().size()+1)));
1313    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1314                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1315      llvm_unreachable("Unexpected abbrev ordering!");
1316  }
1317
1318  { // INTEGER abbrev for CONSTANTS_BLOCK.
1319    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1320    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1321    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1322    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1323                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1324      llvm_unreachable("Unexpected abbrev ordering!");
1325  }
1326
1327  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1328    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1329    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1330    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1331    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1332                              Log2_32_Ceil(VE.getTypes().size()+1)));
1333    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1334
1335    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1336                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1337      llvm_unreachable("Unexpected abbrev ordering!");
1338  }
1339  { // NULL abbrev for CONSTANTS_BLOCK.
1340    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1341    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1342    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1343                                   Abbv) != CONSTANTS_NULL_Abbrev)
1344      llvm_unreachable("Unexpected abbrev ordering!");
1345  }
1346
1347  // FIXME: This should only use space for first class types!
1348
1349  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1350    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1351    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1352    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1353    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1354    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1355    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1356                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1357      llvm_unreachable("Unexpected abbrev ordering!");
1358  }
1359  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1360    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1361    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1362    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1363    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1364    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1365    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1366                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1367      llvm_unreachable("Unexpected abbrev ordering!");
1368  }
1369  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1370    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1371    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1372    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1373    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1374    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1375    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1376    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1377                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1378      llvm_unreachable("Unexpected abbrev ordering!");
1379  }
1380  { // INST_CAST abbrev for FUNCTION_BLOCK.
1381    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1382    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1383    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1384    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1385                              Log2_32_Ceil(VE.getTypes().size()+1)));
1386    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1387    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1388                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1389      llvm_unreachable("Unexpected abbrev ordering!");
1390  }
1391
1392  { // INST_RET abbrev for FUNCTION_BLOCK.
1393    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1394    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1395    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1396                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1397      llvm_unreachable("Unexpected abbrev ordering!");
1398  }
1399  { // INST_RET abbrev for FUNCTION_BLOCK.
1400    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1401    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1402    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1403    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1404                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1405      llvm_unreachable("Unexpected abbrev ordering!");
1406  }
1407  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1408    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1409    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1410    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1411                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1412      llvm_unreachable("Unexpected abbrev ordering!");
1413  }
1414
1415  Stream.ExitBlock();
1416}
1417
1418
1419/// WriteModule - Emit the specified module to the bitstream.
1420static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1421  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1422
1423  // Emit the version number if it is non-zero.
1424  if (CurVersion) {
1425    SmallVector<unsigned, 1> Vals;
1426    Vals.push_back(CurVersion);
1427    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1428  }
1429
1430  // Analyze the module, enumerating globals, functions, etc.
1431  ValueEnumerator VE(M);
1432
1433  // Emit blockinfo, which defines the standard abbreviations etc.
1434  WriteBlockInfo(VE, Stream);
1435
1436  // Emit information about parameter attributes.
1437  WriteAttributeTable(VE, Stream);
1438
1439  // Emit information describing all of the types in the module.
1440  WriteTypeTable(VE, Stream);
1441
1442  // Emit top-level description of module, including target triple, inline asm,
1443  // descriptors for global variables, and function prototype info.
1444  WriteModuleInfo(M, VE, Stream);
1445
1446  // Emit constants.
1447  WriteModuleConstants(VE, Stream);
1448
1449  // Emit metadata.
1450  WriteModuleMetadata(VE, Stream);
1451
1452  // Emit function bodies.
1453  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1454    if (!I->isDeclaration())
1455      WriteFunction(*I, VE, Stream);
1456
1457  // Emit metadata.
1458  WriteModuleMetadataStore(M, Stream);
1459
1460  // Emit the type symbol table information.
1461  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1462
1463  // Emit names for globals/functions etc.
1464  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1465
1466  Stream.ExitBlock();
1467}
1468
1469/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1470/// header and trailer to make it compatible with the system archiver.  To do
1471/// this we emit the following header, and then emit a trailer that pads the
1472/// file out to be a multiple of 16 bytes.
1473///
1474/// struct bc_header {
1475///   uint32_t Magic;         // 0x0B17C0DE
1476///   uint32_t Version;       // Version, currently always 0.
1477///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1478///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1479///   uint32_t CPUType;       // CPU specifier.
1480///   ... potentially more later ...
1481/// };
1482enum {
1483  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1484  DarwinBCHeaderSize = 5*4
1485};
1486
1487static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1488                               const std::string &TT) {
1489  unsigned CPUType = ~0U;
1490
1491  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1492  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1493  // specific constants here because they are implicitly part of the Darwin ABI.
1494  enum {
1495    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1496    DARWIN_CPU_TYPE_X86        = 7,
1497    DARWIN_CPU_TYPE_POWERPC    = 18
1498  };
1499
1500  if (TT.find("x86_64-") == 0)
1501    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1502  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1503           TT[4] == '-' && TT[1] - '3' < 6)
1504    CPUType = DARWIN_CPU_TYPE_X86;
1505  else if (TT.find("powerpc-") == 0)
1506    CPUType = DARWIN_CPU_TYPE_POWERPC;
1507  else if (TT.find("powerpc64-") == 0)
1508    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1509
1510  // Traditional Bitcode starts after header.
1511  unsigned BCOffset = DarwinBCHeaderSize;
1512
1513  Stream.Emit(0x0B17C0DE, 32);
1514  Stream.Emit(0         , 32);  // Version.
1515  Stream.Emit(BCOffset  , 32);
1516  Stream.Emit(0         , 32);  // Filled in later.
1517  Stream.Emit(CPUType   , 32);
1518}
1519
1520/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1521/// finalize the header.
1522static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1523  // Update the size field in the header.
1524  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1525
1526  // If the file is not a multiple of 16 bytes, insert dummy padding.
1527  while (BufferSize & 15) {
1528    Stream.Emit(0, 8);
1529    ++BufferSize;
1530  }
1531}
1532
1533
1534/// WriteBitcodeToFile - Write the specified module to the specified output
1535/// stream.
1536void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1537  std::vector<unsigned char> Buffer;
1538  BitstreamWriter Stream(Buffer);
1539
1540  Buffer.reserve(256*1024);
1541
1542  WriteBitcodeToStream( M, Stream );
1543
1544  // If writing to stdout, set binary mode.
1545  if (&llvm::outs() == &Out)
1546    sys::Program::ChangeStdoutToBinary();
1547
1548  // Write the generated bitstream to "Out".
1549  Out.write((char*)&Buffer.front(), Buffer.size());
1550
1551  // Make sure it hits disk now.
1552  Out.flush();
1553}
1554
1555/// WriteBitcodeToStream - Write the specified module to the specified output
1556/// stream.
1557void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1558  // If this is darwin, emit a file header and trailer if needed.
1559  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1560  if (isDarwin)
1561    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1562
1563  // Emit the file header.
1564  Stream.Emit((unsigned)'B', 8);
1565  Stream.Emit((unsigned)'C', 8);
1566  Stream.Emit(0x0, 4);
1567  Stream.Emit(0xC, 4);
1568  Stream.Emit(0xE, 4);
1569  Stream.Emit(0xD, 4);
1570
1571  // Emit the module.
1572  WriteModule(M, Stream);
1573
1574  if (isDarwin)
1575    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1576}
1577