BitcodeWriter.cpp revision fdfeb6976f07ad10d809b922ed7376ba2a3539be 
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_UNION.
185  Abbv = new BitCodeAbbrev();
186  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_UNION));
187  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
188  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
189                            Log2_32_Ceil(VE.getTypes().size()+1)));
190  unsigned UnionAbbrev = Stream.EmitAbbrev(Abbv);
191
192  // Abbrev for TYPE_CODE_ARRAY.
193  Abbv = new BitCodeAbbrev();
194  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
195  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
196  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
197                            Log2_32_Ceil(VE.getTypes().size()+1)));
198  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
199
200  // Emit an entry count so the reader can reserve space.
201  TypeVals.push_back(TypeList.size());
202  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
203  TypeVals.clear();
204
205  // Loop over all of the types, emitting each in turn.
206  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
207    const Type *T = TypeList[i].first;
208    int AbbrevToUse = 0;
209    unsigned Code = 0;
210
211    switch (T->getTypeID()) {
212    default: llvm_unreachable("Unknown type!");
213    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
214    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
215    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
216    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
217    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
218    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
219    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
220    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
221    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
222    case Type::IntegerTyID:
223      // INTEGER: [width]
224      Code = bitc::TYPE_CODE_INTEGER;
225      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
226      break;
227    case Type::PointerTyID: {
228      const PointerType *PTy = cast<PointerType>(T);
229      // POINTER: [pointee type, address space]
230      Code = bitc::TYPE_CODE_POINTER;
231      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
232      unsigned AddressSpace = PTy->getAddressSpace();
233      TypeVals.push_back(AddressSpace);
234      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
235      break;
236    }
237    case Type::FunctionTyID: {
238      const FunctionType *FT = cast<FunctionType>(T);
239      // FUNCTION: [isvararg, attrid, retty, paramty x N]
240      Code = bitc::TYPE_CODE_FUNCTION;
241      TypeVals.push_back(FT->isVarArg());
242      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
243      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
244      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
245        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
246      AbbrevToUse = FunctionAbbrev;
247      break;
248    }
249    case Type::StructTyID: {
250      const StructType *ST = cast<StructType>(T);
251      // STRUCT: [ispacked, eltty x N]
252      Code = bitc::TYPE_CODE_STRUCT;
253      TypeVals.push_back(ST->isPacked());
254      // Output all of the element types.
255      for (StructType::element_iterator I = ST->element_begin(),
256           E = ST->element_end(); I != E; ++I)
257        TypeVals.push_back(VE.getTypeID(*I));
258      AbbrevToUse = StructAbbrev;
259      break;
260    }
261    case Type::UnionTyID: {
262      const UnionType *UT = cast<UnionType>(T);
263      // UNION: [eltty x N]
264      Code = bitc::TYPE_CODE_UNION;
265      // Output all of the element types.
266      for (UnionType::element_iterator I = UT->element_begin(),
267           E = UT->element_end(); I != E; ++I)
268        TypeVals.push_back(VE.getTypeID(*I));
269      AbbrevToUse = UnionAbbrev;
270      break;
271    }
272    case Type::ArrayTyID: {
273      const ArrayType *AT = cast<ArrayType>(T);
274      // ARRAY: [numelts, eltty]
275      Code = bitc::TYPE_CODE_ARRAY;
276      TypeVals.push_back(AT->getNumElements());
277      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
278      AbbrevToUse = ArrayAbbrev;
279      break;
280    }
281    case Type::VectorTyID: {
282      const VectorType *VT = cast<VectorType>(T);
283      // VECTOR [numelts, eltty]
284      Code = bitc::TYPE_CODE_VECTOR;
285      TypeVals.push_back(VT->getNumElements());
286      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
287      break;
288    }
289    }
290
291    // Emit the finished record.
292    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
293    TypeVals.clear();
294  }
295
296  Stream.ExitBlock();
297}
298
299static unsigned getEncodedLinkage(const GlobalValue *GV) {
300  switch (GV->getLinkage()) {
301  default: llvm_unreachable("Invalid linkage!");
302  case GlobalValue::ExternalLinkage:            return 0;
303  case GlobalValue::WeakAnyLinkage:             return 1;
304  case GlobalValue::AppendingLinkage:           return 2;
305  case GlobalValue::InternalLinkage:            return 3;
306  case GlobalValue::LinkOnceAnyLinkage:         return 4;
307  case GlobalValue::DLLImportLinkage:           return 5;
308  case GlobalValue::DLLExportLinkage:           return 6;
309  case GlobalValue::ExternalWeakLinkage:        return 7;
310  case GlobalValue::CommonLinkage:              return 8;
311  case GlobalValue::PrivateLinkage:             return 9;
312  case GlobalValue::WeakODRLinkage:             return 10;
313  case GlobalValue::LinkOnceODRLinkage:         return 11;
314  case GlobalValue::AvailableExternallyLinkage: return 12;
315  case GlobalValue::LinkerPrivateLinkage:       return 13;
316  }
317}
318
319static unsigned getEncodedVisibility(const GlobalValue *GV) {
320  switch (GV->getVisibility()) {
321  default: llvm_unreachable("Invalid visibility!");
322  case GlobalValue::DefaultVisibility:   return 0;
323  case GlobalValue::HiddenVisibility:    return 1;
324  case GlobalValue::ProtectedVisibility: return 2;
325  }
326}
327
328// Emit top-level description of module, including target triple, inline asm,
329// descriptors for global variables, and function prototype info.
330static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
331                            BitstreamWriter &Stream) {
332  // Emit the list of dependent libraries for the Module.
333  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
334    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
335
336  // Emit various pieces of data attached to a module.
337  if (!M->getTargetTriple().empty())
338    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
339                      0/*TODO*/, Stream);
340  if (!M->getDataLayout().empty())
341    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
342                      0/*TODO*/, Stream);
343  if (!M->getModuleInlineAsm().empty())
344    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
345                      0/*TODO*/, Stream);
346
347  // Emit information about sections and GC, computing how many there are. Also
348  // compute the maximum alignment value.
349  std::map<std::string, unsigned> SectionMap;
350  std::map<std::string, unsigned> GCMap;
351  unsigned MaxAlignment = 0;
352  unsigned MaxGlobalType = 0;
353  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
354       GV != E; ++GV) {
355    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
356    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
357
358    if (!GV->hasSection()) continue;
359    // Give section names unique ID's.
360    unsigned &Entry = SectionMap[GV->getSection()];
361    if (Entry != 0) continue;
362    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
363                      0/*TODO*/, Stream);
364    Entry = SectionMap.size();
365  }
366  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
367    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
368    if (F->hasSection()) {
369      // Give section names unique ID's.
370      unsigned &Entry = SectionMap[F->getSection()];
371      if (!Entry) {
372        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
373                          0/*TODO*/, Stream);
374        Entry = SectionMap.size();
375      }
376    }
377    if (F->hasGC()) {
378      // Same for GC names.
379      unsigned &Entry = GCMap[F->getGC()];
380      if (!Entry) {
381        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
382                          0/*TODO*/, Stream);
383        Entry = GCMap.size();
384      }
385    }
386  }
387
388  // Emit abbrev for globals, now that we know # sections and max alignment.
389  unsigned SimpleGVarAbbrev = 0;
390  if (!M->global_empty()) {
391    // Add an abbrev for common globals with no visibility or thread localness.
392    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
393    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
394    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
395                              Log2_32_Ceil(MaxGlobalType+1)));
396    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
397    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
398    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
399    if (MaxAlignment == 0)                                      // Alignment.
400      Abbv->Add(BitCodeAbbrevOp(0));
401    else {
402      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
403      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
404                               Log2_32_Ceil(MaxEncAlignment+1)));
405    }
406    if (SectionMap.empty())                                    // Section.
407      Abbv->Add(BitCodeAbbrevOp(0));
408    else
409      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
410                               Log2_32_Ceil(SectionMap.size()+1)));
411    // Don't bother emitting vis + thread local.
412    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
413  }
414
415  // Emit the global variable information.
416  SmallVector<unsigned, 64> Vals;
417  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
418       GV != E; ++GV) {
419    unsigned AbbrevToUse = 0;
420
421    // GLOBALVAR: [type, isconst, initid,
422    //             linkage, alignment, section, visibility, threadlocal]
423    Vals.push_back(VE.getTypeID(GV->getType()));
424    Vals.push_back(GV->isConstant());
425    Vals.push_back(GV->isDeclaration() ? 0 :
426                   (VE.getValueID(GV->getInitializer()) + 1));
427    Vals.push_back(getEncodedLinkage(GV));
428    Vals.push_back(Log2_32(GV->getAlignment())+1);
429    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
430    if (GV->isThreadLocal() ||
431        GV->getVisibility() != GlobalValue::DefaultVisibility) {
432      Vals.push_back(getEncodedVisibility(GV));
433      Vals.push_back(GV->isThreadLocal());
434    } else {
435      AbbrevToUse = SimpleGVarAbbrev;
436    }
437
438    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
439    Vals.clear();
440  }
441
442  // Emit the function proto information.
443  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
444    // FUNCTION:  [type, callingconv, isproto, paramattr,
445    //             linkage, alignment, section, visibility, gc]
446    Vals.push_back(VE.getTypeID(F->getType()));
447    Vals.push_back(F->getCallingConv());
448    Vals.push_back(F->isDeclaration());
449    Vals.push_back(getEncodedLinkage(F));
450    Vals.push_back(VE.getAttributeID(F->getAttributes()));
451    Vals.push_back(Log2_32(F->getAlignment())+1);
452    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
453    Vals.push_back(getEncodedVisibility(F));
454    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
455
456    unsigned AbbrevToUse = 0;
457    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
458    Vals.clear();
459  }
460
461
462  // Emit the alias information.
463  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
464       AI != E; ++AI) {
465    Vals.push_back(VE.getTypeID(AI->getType()));
466    Vals.push_back(VE.getValueID(AI->getAliasee()));
467    Vals.push_back(getEncodedLinkage(AI));
468    Vals.push_back(getEncodedVisibility(AI));
469    unsigned AbbrevToUse = 0;
470    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
471    Vals.clear();
472  }
473}
474
475static uint64_t GetOptimizationFlags(const Value *V) {
476  uint64_t Flags = 0;
477
478  if (const OverflowingBinaryOperator *OBO =
479        dyn_cast<OverflowingBinaryOperator>(V)) {
480    if (OBO->hasNoSignedWrap())
481      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
482    if (OBO->hasNoUnsignedWrap())
483      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
484  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
485    if (Div->isExact())
486      Flags |= 1 << bitc::SDIV_EXACT;
487  }
488
489  return Flags;
490}
491
492static void WriteMDNode(const MDNode *N,
493                        const ValueEnumerator &VE,
494                        BitstreamWriter &Stream,
495                        SmallVector<uint64_t, 64> &Record) {
496  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
497    if (N->getOperand(i)) {
498      Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
499      Record.push_back(VE.getValueID(N->getOperand(i)));
500    } else {
501      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
502      Record.push_back(0);
503    }
504  }
505  unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
506                                           bitc::METADATA_NODE;
507  Stream.EmitRecord(MDCode, Record, 0);
508  Record.clear();
509}
510
511static void WriteModuleMetadata(const ValueEnumerator &VE,
512                                BitstreamWriter &Stream) {
513  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
514  bool StartedMetadataBlock = false;
515  unsigned MDSAbbrev = 0;
516  SmallVector<uint64_t, 64> Record;
517  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
518
519    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
520      if (!N->isFunctionLocal() || !N->getFunction()) {
521        if (!StartedMetadataBlock) {
522          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
523          StartedMetadataBlock = true;
524        }
525        WriteMDNode(N, VE, Stream, Record);
526      }
527    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
528      if (!StartedMetadataBlock)  {
529        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
530
531        // Abbrev for METADATA_STRING.
532        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
533        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
534        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
535        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
536        MDSAbbrev = Stream.EmitAbbrev(Abbv);
537        StartedMetadataBlock = true;
538      }
539
540      // Code: [strchar x N]
541      Record.append(MDS->begin(), MDS->end());
542
543      // Emit the finished record.
544      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
545      Record.clear();
546    } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
547      if (!StartedMetadataBlock)  {
548        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
549        StartedMetadataBlock = true;
550      }
551
552      // Write name.
553      StringRef Str = NMD->getName();
554      for (unsigned i = 0, e = Str.size(); i != e; ++i)
555        Record.push_back(Str[i]);
556      Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
557      Record.clear();
558
559      // Write named metadata operands.
560      for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
561        if (NMD->getOperand(i))
562          Record.push_back(VE.getValueID(NMD->getOperand(i)));
563        else
564          Record.push_back(~0U);
565      }
566      Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
567      Record.clear();
568    }
569  }
570
571  if (StartedMetadataBlock)
572    Stream.ExitBlock();
573}
574
575static void WriteFunctionLocalMetadata(const Function &F,
576                                       const ValueEnumerator &VE,
577                                       BitstreamWriter &Stream) {
578  bool StartedMetadataBlock = false;
579  SmallVector<uint64_t, 64> Record;
580  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
581
582  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
583    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first))
584      if (N->isFunctionLocal() && N->getFunction() == &F) {
585        if (!StartedMetadataBlock) {
586          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
587          StartedMetadataBlock = true;
588        }
589        WriteMDNode(N, VE, Stream, Record);
590      }
591
592  if (StartedMetadataBlock)
593    Stream.ExitBlock();
594}
595
596static void WriteMetadataAttachment(const Function &F,
597                                    const ValueEnumerator &VE,
598                                    BitstreamWriter &Stream) {
599  bool StartedMetadataBlock = false;
600  SmallVector<uint64_t, 64> Record;
601
602  // Write metadata attachments
603  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
604  SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
605
606  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
607    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
608         I != E; ++I) {
609      MDs.clear();
610      I->getAllMetadata(MDs);
611
612      // If no metadata, ignore instruction.
613      if (MDs.empty()) continue;
614
615      Record.push_back(VE.getInstructionID(I));
616
617      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
618        Record.push_back(MDs[i].first);
619        Record.push_back(VE.getValueID(MDs[i].second));
620      }
621      if (!StartedMetadataBlock)  {
622        Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
623        StartedMetadataBlock = true;
624      }
625      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
626      Record.clear();
627    }
628
629  if (StartedMetadataBlock)
630    Stream.ExitBlock();
631}
632
633static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
634  SmallVector<uint64_t, 64> Record;
635
636  // Write metadata kinds
637  // METADATA_KIND - [n x [id, name]]
638  SmallVector<StringRef, 4> Names;
639  M->getMDKindNames(Names);
640
641  assert(Names[0] == "" && "MDKind #0 is invalid");
642  if (Names.size() == 1) return;
643
644  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
645
646  for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
647    Record.push_back(MDKindID);
648    StringRef KName = Names[MDKindID];
649    Record.append(KName.begin(), KName.end());
650
651    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
652    Record.clear();
653  }
654
655  Stream.ExitBlock();
656}
657
658static void WriteConstants(unsigned FirstVal, unsigned LastVal,
659                           const ValueEnumerator &VE,
660                           BitstreamWriter &Stream, bool isGlobal) {
661  if (FirstVal == LastVal) return;
662
663  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
664
665  unsigned AggregateAbbrev = 0;
666  unsigned String8Abbrev = 0;
667  unsigned CString7Abbrev = 0;
668  unsigned CString6Abbrev = 0;
669  // If this is a constant pool for the module, emit module-specific abbrevs.
670  if (isGlobal) {
671    // Abbrev for CST_CODE_AGGREGATE.
672    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
673    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
674    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
675    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
676    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
677
678    // Abbrev for CST_CODE_STRING.
679    Abbv = new BitCodeAbbrev();
680    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
681    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
682    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
683    String8Abbrev = Stream.EmitAbbrev(Abbv);
684    // Abbrev for CST_CODE_CSTRING.
685    Abbv = new BitCodeAbbrev();
686    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
687    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
688    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
689    CString7Abbrev = Stream.EmitAbbrev(Abbv);
690    // Abbrev for CST_CODE_CSTRING.
691    Abbv = new BitCodeAbbrev();
692    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
693    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
694    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
695    CString6Abbrev = Stream.EmitAbbrev(Abbv);
696  }
697
698  SmallVector<uint64_t, 64> Record;
699
700  const ValueEnumerator::ValueList &Vals = VE.getValues();
701  const Type *LastTy = 0;
702  for (unsigned i = FirstVal; i != LastVal; ++i) {
703    const Value *V = Vals[i].first;
704    // If we need to switch types, do so now.
705    if (V->getType() != LastTy) {
706      LastTy = V->getType();
707      Record.push_back(VE.getTypeID(LastTy));
708      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
709                        CONSTANTS_SETTYPE_ABBREV);
710      Record.clear();
711    }
712
713    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
714      Record.push_back(unsigned(IA->hasSideEffects()) |
715                       unsigned(IA->isAlignStack()) << 1);
716
717      // Add the asm string.
718      const std::string &AsmStr = IA->getAsmString();
719      Record.push_back(AsmStr.size());
720      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
721        Record.push_back(AsmStr[i]);
722
723      // Add the constraint string.
724      const std::string &ConstraintStr = IA->getConstraintString();
725      Record.push_back(ConstraintStr.size());
726      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
727        Record.push_back(ConstraintStr[i]);
728      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
729      Record.clear();
730      continue;
731    }
732    const Constant *C = cast<Constant>(V);
733    unsigned Code = -1U;
734    unsigned AbbrevToUse = 0;
735    if (C->isNullValue()) {
736      Code = bitc::CST_CODE_NULL;
737    } else if (isa<UndefValue>(C)) {
738      Code = bitc::CST_CODE_UNDEF;
739    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
740      if (IV->getBitWidth() <= 64) {
741        int64_t V = IV->getSExtValue();
742        if (V >= 0)
743          Record.push_back(V << 1);
744        else
745          Record.push_back((-V << 1) | 1);
746        Code = bitc::CST_CODE_INTEGER;
747        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
748      } else {                             // Wide integers, > 64 bits in size.
749        // We have an arbitrary precision integer value to write whose
750        // bit width is > 64. However, in canonical unsigned integer
751        // format it is likely that the high bits are going to be zero.
752        // So, we only write the number of active words.
753        unsigned NWords = IV->getValue().getActiveWords();
754        const uint64_t *RawWords = IV->getValue().getRawData();
755        for (unsigned i = 0; i != NWords; ++i) {
756          int64_t V = RawWords[i];
757          if (V >= 0)
758            Record.push_back(V << 1);
759          else
760            Record.push_back((-V << 1) | 1);
761        }
762        Code = bitc::CST_CODE_WIDE_INTEGER;
763      }
764    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
765      Code = bitc::CST_CODE_FLOAT;
766      const Type *Ty = CFP->getType();
767      if (Ty->isFloatTy() || Ty->isDoubleTy()) {
768        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
769      } else if (Ty->isX86_FP80Ty()) {
770        // api needed to prevent premature destruction
771        // bits are not in the same order as a normal i80 APInt, compensate.
772        APInt api = CFP->getValueAPF().bitcastToAPInt();
773        const uint64_t *p = api.getRawData();
774        Record.push_back((p[1] << 48) | (p[0] >> 16));
775        Record.push_back(p[0] & 0xffffLL);
776      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
777        APInt api = CFP->getValueAPF().bitcastToAPInt();
778        const uint64_t *p = api.getRawData();
779        Record.push_back(p[0]);
780        Record.push_back(p[1]);
781      } else {
782        assert (0 && "Unknown FP type!");
783      }
784    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
785      const ConstantArray *CA = cast<ConstantArray>(C);
786      // Emit constant strings specially.
787      unsigned NumOps = CA->getNumOperands();
788      // If this is a null-terminated string, use the denser CSTRING encoding.
789      if (CA->getOperand(NumOps-1)->isNullValue()) {
790        Code = bitc::CST_CODE_CSTRING;
791        --NumOps;  // Don't encode the null, which isn't allowed by char6.
792      } else {
793        Code = bitc::CST_CODE_STRING;
794        AbbrevToUse = String8Abbrev;
795      }
796      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
797      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
798      for (unsigned i = 0; i != NumOps; ++i) {
799        unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
800        Record.push_back(V);
801        isCStr7 &= (V & 128) == 0;
802        if (isCStrChar6)
803          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
804      }
805
806      if (isCStrChar6)
807        AbbrevToUse = CString6Abbrev;
808      else if (isCStr7)
809        AbbrevToUse = CString7Abbrev;
810    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
811               isa<ConstantUnion>(C) || isa<ConstantVector>(V)) {
812      Code = bitc::CST_CODE_AGGREGATE;
813      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
814        Record.push_back(VE.getValueID(C->getOperand(i)));
815      AbbrevToUse = AggregateAbbrev;
816    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
817      switch (CE->getOpcode()) {
818      default:
819        if (Instruction::isCast(CE->getOpcode())) {
820          Code = bitc::CST_CODE_CE_CAST;
821          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
822          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
823          Record.push_back(VE.getValueID(C->getOperand(0)));
824          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
825        } else {
826          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
827          Code = bitc::CST_CODE_CE_BINOP;
828          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
829          Record.push_back(VE.getValueID(C->getOperand(0)));
830          Record.push_back(VE.getValueID(C->getOperand(1)));
831          uint64_t Flags = GetOptimizationFlags(CE);
832          if (Flags != 0)
833            Record.push_back(Flags);
834        }
835        break;
836      case Instruction::GetElementPtr:
837        Code = bitc::CST_CODE_CE_GEP;
838        if (cast<GEPOperator>(C)->isInBounds())
839          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
840        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
841          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
842          Record.push_back(VE.getValueID(C->getOperand(i)));
843        }
844        break;
845      case Instruction::Select:
846        Code = bitc::CST_CODE_CE_SELECT;
847        Record.push_back(VE.getValueID(C->getOperand(0)));
848        Record.push_back(VE.getValueID(C->getOperand(1)));
849        Record.push_back(VE.getValueID(C->getOperand(2)));
850        break;
851      case Instruction::ExtractElement:
852        Code = bitc::CST_CODE_CE_EXTRACTELT;
853        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
854        Record.push_back(VE.getValueID(C->getOperand(0)));
855        Record.push_back(VE.getValueID(C->getOperand(1)));
856        break;
857      case Instruction::InsertElement:
858        Code = bitc::CST_CODE_CE_INSERTELT;
859        Record.push_back(VE.getValueID(C->getOperand(0)));
860        Record.push_back(VE.getValueID(C->getOperand(1)));
861        Record.push_back(VE.getValueID(C->getOperand(2)));
862        break;
863      case Instruction::ShuffleVector:
864        // If the return type and argument types are the same, this is a
865        // standard shufflevector instruction.  If the types are different,
866        // then the shuffle is widening or truncating the input vectors, and
867        // the argument type must also be encoded.
868        if (C->getType() == C->getOperand(0)->getType()) {
869          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
870        } else {
871          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
872          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
873        }
874        Record.push_back(VE.getValueID(C->getOperand(0)));
875        Record.push_back(VE.getValueID(C->getOperand(1)));
876        Record.push_back(VE.getValueID(C->getOperand(2)));
877        break;
878      case Instruction::ICmp:
879      case Instruction::FCmp:
880        Code = bitc::CST_CODE_CE_CMP;
881        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
882        Record.push_back(VE.getValueID(C->getOperand(0)));
883        Record.push_back(VE.getValueID(C->getOperand(1)));
884        Record.push_back(CE->getPredicate());
885        break;
886      }
887    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
888      assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
889             "Malformed blockaddress");
890      Code = bitc::CST_CODE_BLOCKADDRESS;
891      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
892      Record.push_back(VE.getValueID(BA->getFunction()));
893      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
894    } else {
895      llvm_unreachable("Unknown constant!");
896    }
897    Stream.EmitRecord(Code, Record, AbbrevToUse);
898    Record.clear();
899  }
900
901  Stream.ExitBlock();
902}
903
904static void WriteModuleConstants(const ValueEnumerator &VE,
905                                 BitstreamWriter &Stream) {
906  const ValueEnumerator::ValueList &Vals = VE.getValues();
907
908  // Find the first constant to emit, which is the first non-globalvalue value.
909  // We know globalvalues have been emitted by WriteModuleInfo.
910  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
911    if (!isa<GlobalValue>(Vals[i].first)) {
912      WriteConstants(i, Vals.size(), VE, Stream, true);
913      return;
914    }
915  }
916}
917
918/// PushValueAndType - The file has to encode both the value and type id for
919/// many values, because we need to know what type to create for forward
920/// references.  However, most operands are not forward references, so this type
921/// field is not needed.
922///
923/// This function adds V's value ID to Vals.  If the value ID is higher than the
924/// instruction ID, then it is a forward reference, and it also includes the
925/// type ID.
926static bool PushValueAndType(const Value *V, unsigned InstID,
927                             SmallVector<unsigned, 64> &Vals,
928                             ValueEnumerator &VE) {
929  unsigned ValID = VE.getValueID(V);
930  Vals.push_back(ValID);
931  if (ValID >= InstID) {
932    Vals.push_back(VE.getTypeID(V->getType()));
933    return true;
934  }
935  return false;
936}
937
938/// WriteInstruction - Emit an instruction to the specified stream.
939static void WriteInstruction(const Instruction &I, unsigned InstID,
940                             ValueEnumerator &VE, BitstreamWriter &Stream,
941                             SmallVector<unsigned, 64> &Vals) {
942  unsigned Code = 0;
943  unsigned AbbrevToUse = 0;
944  VE.setInstructionID(&I);
945  switch (I.getOpcode()) {
946  default:
947    if (Instruction::isCast(I.getOpcode())) {
948      Code = bitc::FUNC_CODE_INST_CAST;
949      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
950        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
951      Vals.push_back(VE.getTypeID(I.getType()));
952      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
953    } else {
954      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
955      Code = bitc::FUNC_CODE_INST_BINOP;
956      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
957        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
958      Vals.push_back(VE.getValueID(I.getOperand(1)));
959      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
960      uint64_t Flags = GetOptimizationFlags(&I);
961      if (Flags != 0) {
962        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
963          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
964        Vals.push_back(Flags);
965      }
966    }
967    break;
968
969  case Instruction::GetElementPtr:
970    Code = bitc::FUNC_CODE_INST_GEP;
971    if (cast<GEPOperator>(&I)->isInBounds())
972      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
973    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
974      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
975    break;
976  case Instruction::ExtractValue: {
977    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
978    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
979    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
980    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
981      Vals.push_back(*i);
982    break;
983  }
984  case Instruction::InsertValue: {
985    Code = bitc::FUNC_CODE_INST_INSERTVAL;
986    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
987    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
988    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
989    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
990      Vals.push_back(*i);
991    break;
992  }
993  case Instruction::Select:
994    Code = bitc::FUNC_CODE_INST_VSELECT;
995    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
996    Vals.push_back(VE.getValueID(I.getOperand(2)));
997    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
998    break;
999  case Instruction::ExtractElement:
1000    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1001    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1002    Vals.push_back(VE.getValueID(I.getOperand(1)));
1003    break;
1004  case Instruction::InsertElement:
1005    Code = bitc::FUNC_CODE_INST_INSERTELT;
1006    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1007    Vals.push_back(VE.getValueID(I.getOperand(1)));
1008    Vals.push_back(VE.getValueID(I.getOperand(2)));
1009    break;
1010  case Instruction::ShuffleVector:
1011    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1012    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1013    Vals.push_back(VE.getValueID(I.getOperand(1)));
1014    Vals.push_back(VE.getValueID(I.getOperand(2)));
1015    break;
1016  case Instruction::ICmp:
1017  case Instruction::FCmp:
1018    // compare returning Int1Ty or vector of Int1Ty
1019    Code = bitc::FUNC_CODE_INST_CMP2;
1020    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1021    Vals.push_back(VE.getValueID(I.getOperand(1)));
1022    Vals.push_back(cast<CmpInst>(I).getPredicate());
1023    break;
1024
1025  case Instruction::Ret:
1026    {
1027      Code = bitc::FUNC_CODE_INST_RET;
1028      unsigned NumOperands = I.getNumOperands();
1029      if (NumOperands == 0)
1030        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1031      else if (NumOperands == 1) {
1032        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1033          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1034      } else {
1035        for (unsigned i = 0, e = NumOperands; i != e; ++i)
1036          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1037      }
1038    }
1039    break;
1040  case Instruction::Br:
1041    {
1042      Code = bitc::FUNC_CODE_INST_BR;
1043      BranchInst &II = cast<BranchInst>(I);
1044      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1045      if (II.isConditional()) {
1046        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1047        Vals.push_back(VE.getValueID(II.getCondition()));
1048      }
1049    }
1050    break;
1051  case Instruction::Switch:
1052    Code = bitc::FUNC_CODE_INST_SWITCH;
1053    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1054    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1055      Vals.push_back(VE.getValueID(I.getOperand(i)));
1056    break;
1057  case Instruction::IndirectBr:
1058    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1059    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1060    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1061      Vals.push_back(VE.getValueID(I.getOperand(i)));
1062    break;
1063
1064  case Instruction::Invoke: {
1065    const InvokeInst *II = cast<InvokeInst>(&I);
1066    const Value *Callee(II->getCalledValue());
1067    const PointerType *PTy = cast<PointerType>(Callee->getType());
1068    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1069    Code = bitc::FUNC_CODE_INST_INVOKE;
1070
1071    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1072    Vals.push_back(II->getCallingConv());
1073    Vals.push_back(VE.getValueID(II->getNormalDest()));
1074    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1075    PushValueAndType(Callee, InstID, Vals, VE);
1076
1077    // Emit value #'s for the fixed parameters.
1078    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1079      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1080
1081    // Emit type/value pairs for varargs params.
1082    if (FTy->isVarArg()) {
1083      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1084           i != e; ++i)
1085        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1086    }
1087    break;
1088  }
1089  case Instruction::Unwind:
1090    Code = bitc::FUNC_CODE_INST_UNWIND;
1091    break;
1092  case Instruction::Unreachable:
1093    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1094    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1095    break;
1096
1097  case Instruction::PHI:
1098    Code = bitc::FUNC_CODE_INST_PHI;
1099    Vals.push_back(VE.getTypeID(I.getType()));
1100    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1101      Vals.push_back(VE.getValueID(I.getOperand(i)));
1102    break;
1103
1104  case Instruction::Alloca:
1105    Code = bitc::FUNC_CODE_INST_ALLOCA;
1106    Vals.push_back(VE.getTypeID(I.getType()));
1107    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1108    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1109    break;
1110
1111  case Instruction::Load:
1112    Code = bitc::FUNC_CODE_INST_LOAD;
1113    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1114      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1115
1116    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1117    Vals.push_back(cast<LoadInst>(I).isVolatile());
1118    break;
1119  case Instruction::Store:
1120    Code = bitc::FUNC_CODE_INST_STORE2;
1121    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1122    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1123    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1124    Vals.push_back(cast<StoreInst>(I).isVolatile());
1125    break;
1126  case Instruction::Call: {
1127    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1128    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1129
1130    Code = bitc::FUNC_CODE_INST_CALL;
1131
1132    const CallInst *CI = cast<CallInst>(&I);
1133    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1134    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1135    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1136
1137    // Emit value #'s for the fixed parameters.
1138    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1139      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1140
1141    // Emit type/value pairs for varargs params.
1142    if (FTy->isVarArg()) {
1143      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1144      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1145           i != e; ++i)
1146        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1147    }
1148    break;
1149  }
1150  case Instruction::VAArg:
1151    Code = bitc::FUNC_CODE_INST_VAARG;
1152    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1153    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1154    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1155    break;
1156  }
1157
1158  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1159  Vals.clear();
1160}
1161
1162// Emit names for globals/functions etc.
1163static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1164                                  const ValueEnumerator &VE,
1165                                  BitstreamWriter &Stream) {
1166  if (VST.empty()) return;
1167  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1168
1169  // FIXME: Set up the abbrev, we know how many values there are!
1170  // FIXME: We know if the type names can use 7-bit ascii.
1171  SmallVector<unsigned, 64> NameVals;
1172
1173  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1174       SI != SE; ++SI) {
1175
1176    const ValueName &Name = *SI;
1177
1178    // Figure out the encoding to use for the name.
1179    bool is7Bit = true;
1180    bool isChar6 = true;
1181    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1182         C != E; ++C) {
1183      if (isChar6)
1184        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1185      if ((unsigned char)*C & 128) {
1186        is7Bit = false;
1187        break;  // don't bother scanning the rest.
1188      }
1189    }
1190
1191    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1192
1193    // VST_ENTRY:   [valueid, namechar x N]
1194    // VST_BBENTRY: [bbid, namechar x N]
1195    unsigned Code;
1196    if (isa<BasicBlock>(SI->getValue())) {
1197      Code = bitc::VST_CODE_BBENTRY;
1198      if (isChar6)
1199        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1200    } else {
1201      Code = bitc::VST_CODE_ENTRY;
1202      if (isChar6)
1203        AbbrevToUse = VST_ENTRY_6_ABBREV;
1204      else if (is7Bit)
1205        AbbrevToUse = VST_ENTRY_7_ABBREV;
1206    }
1207
1208    NameVals.push_back(VE.getValueID(SI->getValue()));
1209    for (const char *P = Name.getKeyData(),
1210         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1211      NameVals.push_back((unsigned char)*P);
1212
1213    // Emit the finished record.
1214    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1215    NameVals.clear();
1216  }
1217  Stream.ExitBlock();
1218}
1219
1220/// WriteFunction - Emit a function body to the module stream.
1221static void WriteFunction(const Function &F, ValueEnumerator &VE,
1222                          BitstreamWriter &Stream) {
1223  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1224  VE.incorporateFunction(F);
1225
1226  SmallVector<unsigned, 64> Vals;
1227
1228  // Emit the number of basic blocks, so the reader can create them ahead of
1229  // time.
1230  Vals.push_back(VE.getBasicBlocks().size());
1231  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1232  Vals.clear();
1233
1234  // If there are function-local constants, emit them now.
1235  unsigned CstStart, CstEnd;
1236  VE.getFunctionConstantRange(CstStart, CstEnd);
1237  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1238
1239  // If there is function-local metadata, emit it now.
1240  WriteFunctionLocalMetadata(F, VE, Stream);
1241
1242  // Keep a running idea of what the instruction ID is.
1243  unsigned InstID = CstEnd;
1244
1245  // Finally, emit all the instructions, in order.
1246  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1247    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1248         I != E; ++I) {
1249      WriteInstruction(*I, InstID, VE, Stream, Vals);
1250      if (!I->getType()->isVoidTy())
1251        ++InstID;
1252    }
1253
1254  // Emit names for all the instructions etc.
1255  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1256
1257  WriteMetadataAttachment(F, VE, Stream);
1258  VE.purgeFunction();
1259  Stream.ExitBlock();
1260}
1261
1262/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1263static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1264                                 const ValueEnumerator &VE,
1265                                 BitstreamWriter &Stream) {
1266  if (TST.empty()) return;
1267
1268  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1269
1270  // 7-bit fixed width VST_CODE_ENTRY strings.
1271  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1272  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1273  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1274                            Log2_32_Ceil(VE.getTypes().size()+1)));
1275  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1276  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1277  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1278
1279  SmallVector<unsigned, 64> NameVals;
1280
1281  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1282       TI != TE; ++TI) {
1283    // TST_ENTRY: [typeid, namechar x N]
1284    NameVals.push_back(VE.getTypeID(TI->second));
1285
1286    const std::string &Str = TI->first;
1287    bool is7Bit = true;
1288    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1289      NameVals.push_back((unsigned char)Str[i]);
1290      if (Str[i] & 128)
1291        is7Bit = false;
1292    }
1293
1294    // Emit the finished record.
1295    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1296    NameVals.clear();
1297  }
1298
1299  Stream.ExitBlock();
1300}
1301
1302// Emit blockinfo, which defines the standard abbreviations etc.
1303static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1304  // We only want to emit block info records for blocks that have multiple
1305  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1306  // blocks can defined their abbrevs inline.
1307  Stream.EnterBlockInfoBlock(2);
1308
1309  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1310    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1311    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1312    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1313    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1314    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1315    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1316                                   Abbv) != VST_ENTRY_8_ABBREV)
1317      llvm_unreachable("Unexpected abbrev ordering!");
1318  }
1319
1320  { // 7-bit fixed width VST_ENTRY strings.
1321    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1322    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1323    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1324    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1325    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1326    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1327                                   Abbv) != VST_ENTRY_7_ABBREV)
1328      llvm_unreachable("Unexpected abbrev ordering!");
1329  }
1330  { // 6-bit char6 VST_ENTRY strings.
1331    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1332    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1333    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1334    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1335    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1336    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1337                                   Abbv) != VST_ENTRY_6_ABBREV)
1338      llvm_unreachable("Unexpected abbrev ordering!");
1339  }
1340  { // 6-bit char6 VST_BBENTRY strings.
1341    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1342    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1343    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1344    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1345    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1346    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1347                                   Abbv) != VST_BBENTRY_6_ABBREV)
1348      llvm_unreachable("Unexpected abbrev ordering!");
1349  }
1350
1351
1352
1353  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1354    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1355    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1356    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1357                              Log2_32_Ceil(VE.getTypes().size()+1)));
1358    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1359                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1360      llvm_unreachable("Unexpected abbrev ordering!");
1361  }
1362
1363  { // INTEGER abbrev for CONSTANTS_BLOCK.
1364    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1365    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1366    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1367    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1368                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1369      llvm_unreachable("Unexpected abbrev ordering!");
1370  }
1371
1372  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1373    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1374    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1375    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1376    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1377                              Log2_32_Ceil(VE.getTypes().size()+1)));
1378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1379
1380    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1381                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1382      llvm_unreachable("Unexpected abbrev ordering!");
1383  }
1384  { // NULL abbrev for CONSTANTS_BLOCK.
1385    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1386    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1387    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1388                                   Abbv) != CONSTANTS_NULL_Abbrev)
1389      llvm_unreachable("Unexpected abbrev ordering!");
1390  }
1391
1392  // FIXME: This should only use space for first class types!
1393
1394  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1395    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1396    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1397    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1398    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1399    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1400    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1401                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1402      llvm_unreachable("Unexpected abbrev ordering!");
1403  }
1404  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1405    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1406    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1407    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1408    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1409    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1410    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1411                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1412      llvm_unreachable("Unexpected abbrev ordering!");
1413  }
1414  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1415    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1416    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1417    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1418    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1419    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1420    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1421    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1422                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1423      llvm_unreachable("Unexpected abbrev ordering!");
1424  }
1425  { // INST_CAST abbrev for FUNCTION_BLOCK.
1426    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1427    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1428    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1429    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1430                              Log2_32_Ceil(VE.getTypes().size()+1)));
1431    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1432    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1433                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1434      llvm_unreachable("Unexpected abbrev ordering!");
1435  }
1436
1437  { // INST_RET abbrev for FUNCTION_BLOCK.
1438    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1439    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1440    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1441                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1442      llvm_unreachable("Unexpected abbrev ordering!");
1443  }
1444  { // INST_RET abbrev for FUNCTION_BLOCK.
1445    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1446    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1447    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1448    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1449                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1450      llvm_unreachable("Unexpected abbrev ordering!");
1451  }
1452  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1453    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1454    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1455    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1456                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1457      llvm_unreachable("Unexpected abbrev ordering!");
1458  }
1459
1460  Stream.ExitBlock();
1461}
1462
1463
1464/// WriteModule - Emit the specified module to the bitstream.
1465static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1466  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1467
1468  // Emit the version number if it is non-zero.
1469  if (CurVersion) {
1470    SmallVector<unsigned, 1> Vals;
1471    Vals.push_back(CurVersion);
1472    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1473  }
1474
1475  // Analyze the module, enumerating globals, functions, etc.
1476  ValueEnumerator VE(M);
1477
1478  // Emit blockinfo, which defines the standard abbreviations etc.
1479  WriteBlockInfo(VE, Stream);
1480
1481  // Emit information about parameter attributes.
1482  WriteAttributeTable(VE, Stream);
1483
1484  // Emit information describing all of the types in the module.
1485  WriteTypeTable(VE, Stream);
1486
1487  // Emit top-level description of module, including target triple, inline asm,
1488  // descriptors for global variables, and function prototype info.
1489  WriteModuleInfo(M, VE, Stream);
1490
1491  // Emit constants.
1492  WriteModuleConstants(VE, Stream);
1493
1494  // Emit metadata.
1495  WriteModuleMetadata(VE, Stream);
1496
1497  // Emit function bodies.
1498  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1499    if (!I->isDeclaration())
1500      WriteFunction(*I, VE, Stream);
1501
1502  // Emit metadata.
1503  WriteModuleMetadataStore(M, Stream);
1504
1505  // Emit the type symbol table information.
1506  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1507
1508  // Emit names for globals/functions etc.
1509  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1510
1511  Stream.ExitBlock();
1512}
1513
1514/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1515/// header and trailer to make it compatible with the system archiver.  To do
1516/// this we emit the following header, and then emit a trailer that pads the
1517/// file out to be a multiple of 16 bytes.
1518///
1519/// struct bc_header {
1520///   uint32_t Magic;         // 0x0B17C0DE
1521///   uint32_t Version;       // Version, currently always 0.
1522///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1523///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1524///   uint32_t CPUType;       // CPU specifier.
1525///   ... potentially more later ...
1526/// };
1527enum {
1528  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1529  DarwinBCHeaderSize = 5*4
1530};
1531
1532/// isARMTriplet - Return true if the triplet looks like:
1533/// arm-*, thumb-*, armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*.
1534static bool isARMTriplet(const std::string &TT) {
1535  size_t Pos = 0;
1536  size_t Size = TT.size();
1537  if (Size >= 6 &&
1538      TT[0] == 't' && TT[1] == 'h' && TT[2] == 'u' &&
1539      TT[3] == 'm' && TT[4] == 'b')
1540    Pos = 5;
1541  else if (Size >= 4 && TT[0] == 'a' && TT[1] == 'r' && TT[2] == 'm')
1542    Pos = 3;
1543  else
1544    return false;
1545
1546  if (TT[Pos] == '-')
1547    return true;
1548  else if (TT[Pos] == 'v') {
1549    if (Size >= Pos+4 &&
1550        TT[Pos+1] == '6' && TT[Pos+2] == 't' && TT[Pos+3] == '2')
1551      return true;
1552    else if (Size >= Pos+4 &&
1553             TT[Pos+1] == '5' && TT[Pos+2] == 't' && TT[Pos+3] == 'e')
1554      return true;
1555  } else
1556    return false;
1557  while (++Pos < Size && TT[Pos] != '-') {
1558    if (!isdigit(TT[Pos]))
1559      return false;
1560  }
1561  return true;
1562}
1563
1564static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1565                               const std::string &TT) {
1566  unsigned CPUType = ~0U;
1567
1568  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1569  // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1570  // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1571  // specific constants here because they are implicitly part of the Darwin ABI.
1572  enum {
1573    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1574    DARWIN_CPU_TYPE_X86        = 7,
1575    DARWIN_CPU_TYPE_ARM        = 12,
1576    DARWIN_CPU_TYPE_POWERPC    = 18
1577  };
1578
1579  if (TT.find("x86_64-") == 0)
1580    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1581  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1582           TT[4] == '-' && TT[1] - '3' < 6)
1583    CPUType = DARWIN_CPU_TYPE_X86;
1584  else if (TT.find("powerpc-") == 0)
1585    CPUType = DARWIN_CPU_TYPE_POWERPC;
1586  else if (TT.find("powerpc64-") == 0)
1587    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1588  else if (isARMTriplet(TT))
1589    CPUType = DARWIN_CPU_TYPE_ARM;
1590
1591  // Traditional Bitcode starts after header.
1592  unsigned BCOffset = DarwinBCHeaderSize;
1593
1594  Stream.Emit(0x0B17C0DE, 32);
1595  Stream.Emit(0         , 32);  // Version.
1596  Stream.Emit(BCOffset  , 32);
1597  Stream.Emit(0         , 32);  // Filled in later.
1598  Stream.Emit(CPUType   , 32);
1599}
1600
1601/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1602/// finalize the header.
1603static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1604  // Update the size field in the header.
1605  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1606
1607  // If the file is not a multiple of 16 bytes, insert dummy padding.
1608  while (BufferSize & 15) {
1609    Stream.Emit(0, 8);
1610    ++BufferSize;
1611  }
1612}
1613
1614
1615/// WriteBitcodeToFile - Write the specified module to the specified output
1616/// stream.
1617void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1618  std::vector<unsigned char> Buffer;
1619  BitstreamWriter Stream(Buffer);
1620
1621  Buffer.reserve(256*1024);
1622
1623  WriteBitcodeToStream( M, Stream );
1624
1625  // If writing to stdout, set binary mode.
1626  if (&llvm::outs() == &Out)
1627    sys::Program::ChangeStdoutToBinary();
1628
1629  // Write the generated bitstream to "Out".
1630  Out.write((char*)&Buffer.front(), Buffer.size());
1631
1632  // Make sure it hits disk now.
1633  Out.flush();
1634}
1635
1636/// WriteBitcodeToStream - Write the specified module to the specified output
1637/// stream.
1638void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1639  // If this is darwin, emit a file header and trailer if needed.
1640  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1641  if (isDarwin)
1642    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1643
1644  // Emit the file header.
1645  Stream.Emit((unsigned)'B', 8);
1646  Stream.Emit((unsigned)'C', 8);
1647  Stream.Emit(0x0, 4);
1648  Stream.Emit(0xC, 4);
1649  Stream.Emit(0xE, 4);
1650  Stream.Emit(0xD, 4);
1651
1652  // Emit the module.
1653  WriteModule(M, Stream);
1654
1655  if (isDarwin)
1656    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1657}
1658