BitcodeWriter.cpp revision 7d05c46d601cbb52be605019548c34286c02e3a3 
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/LLVMContext.h"
23#include "llvm/Metadata.h"
24#include "llvm/Module.h"
25#include "llvm/Operator.h"
26#include "llvm/TypeSymbolTable.h"
27#include "llvm/ValueSymbolTable.h"
28#include "llvm/Support/ErrorHandling.h"
29#include "llvm/Support/MathExtras.h"
30#include "llvm/Support/raw_ostream.h"
31#include "llvm/System/Program.h"
32using namespace llvm;
33
34/// These are manifest constants used by the bitcode writer. They do not need to
35/// be kept in sync with the reader, but need to be consistent within this file.
36enum {
37  CurVersion = 0,
38
39  // VALUE_SYMTAB_BLOCK abbrev id's.
40  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
41  VST_ENTRY_7_ABBREV,
42  VST_ENTRY_6_ABBREV,
43  VST_BBENTRY_6_ABBREV,
44
45  // CONSTANTS_BLOCK abbrev id's.
46  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
47  CONSTANTS_INTEGER_ABBREV,
48  CONSTANTS_CE_CAST_Abbrev,
49  CONSTANTS_NULL_Abbrev,
50
51  // FUNCTION_BLOCK abbrev id's.
52  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
53  FUNCTION_INST_BINOP_ABBREV,
54  FUNCTION_INST_BINOP_FLAGS_ABBREV,
55  FUNCTION_INST_CAST_ABBREV,
56  FUNCTION_INST_RET_VOID_ABBREV,
57  FUNCTION_INST_RET_VAL_ABBREV,
58  FUNCTION_INST_UNREACHABLE_ABBREV
59};
60
61
62static unsigned GetEncodedCastOpcode(unsigned Opcode) {
63  switch (Opcode) {
64  default: llvm_unreachable("Unknown cast instruction!");
65  case Instruction::Trunc   : return bitc::CAST_TRUNC;
66  case Instruction::ZExt    : return bitc::CAST_ZEXT;
67  case Instruction::SExt    : return bitc::CAST_SEXT;
68  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
69  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
70  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
71  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
72  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
73  case Instruction::FPExt   : return bitc::CAST_FPEXT;
74  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
75  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
76  case Instruction::BitCast : return bitc::CAST_BITCAST;
77  }
78}
79
80static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
81  switch (Opcode) {
82  default: llvm_unreachable("Unknown binary instruction!");
83  case Instruction::Add:
84  case Instruction::FAdd: return bitc::BINOP_ADD;
85  case Instruction::Sub:
86  case Instruction::FSub: return bitc::BINOP_SUB;
87  case Instruction::Mul:
88  case Instruction::FMul: return bitc::BINOP_MUL;
89  case Instruction::UDiv: return bitc::BINOP_UDIV;
90  case Instruction::FDiv:
91  case Instruction::SDiv: return bitc::BINOP_SDIV;
92  case Instruction::URem: return bitc::BINOP_UREM;
93  case Instruction::FRem:
94  case Instruction::SRem: return bitc::BINOP_SREM;
95  case Instruction::Shl:  return bitc::BINOP_SHL;
96  case Instruction::LShr: return bitc::BINOP_LSHR;
97  case Instruction::AShr: return bitc::BINOP_ASHR;
98  case Instruction::And:  return bitc::BINOP_AND;
99  case Instruction::Or:   return bitc::BINOP_OR;
100  case Instruction::Xor:  return bitc::BINOP_XOR;
101  }
102}
103
104
105
106static void WriteStringRecord(unsigned Code, const std::string &Str,
107                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
108  SmallVector<unsigned, 64> Vals;
109
110  // Code: [strchar x N]
111  for (unsigned i = 0, e = Str.size(); i != e; ++i)
112    Vals.push_back(Str[i]);
113
114  // Emit the finished record.
115  Stream.EmitRecord(Code, Vals, AbbrevToUse);
116}
117
118// Emit information about parameter attributes.
119static void WriteAttributeTable(const ValueEnumerator &VE,
120                                BitstreamWriter &Stream) {
121  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
122  if (Attrs.empty()) return;
123
124  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
125
126  SmallVector<uint64_t, 64> Record;
127  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
128    const AttrListPtr &A = Attrs[i];
129    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
130      const AttributeWithIndex &PAWI = A.getSlot(i);
131      Record.push_back(PAWI.Index);
132
133      // FIXME: remove in LLVM 3.0
134      // Store the alignment in the bitcode as a 16-bit raw value instead of a
135      // 5-bit log2 encoded value. Shift the bits above the alignment up by
136      // 11 bits.
137      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
138      if (PAWI.Attrs & Attribute::Alignment)
139        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
140      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
141
142      Record.push_back(FauxAttr);
143    }
144
145    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
146    Record.clear();
147  }
148
149  Stream.ExitBlock();
150}
151
152/// WriteTypeTable - Write out the type table for a module.
153static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
154  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
155
156  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
157  SmallVector<uint64_t, 64> TypeVals;
158
159  // Abbrev for TYPE_CODE_POINTER.
160  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
161  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
162  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
163                            Log2_32_Ceil(VE.getTypes().size()+1)));
164  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
165  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
166
167  // Abbrev for TYPE_CODE_FUNCTION.
168  Abbv = new BitCodeAbbrev();
169  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
171  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
172  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
173  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
174                            Log2_32_Ceil(VE.getTypes().size()+1)));
175  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
176
177  // Abbrev for TYPE_CODE_STRUCT.
178  Abbv = new BitCodeAbbrev();
179  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
181  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
182  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
183                            Log2_32_Ceil(VE.getTypes().size()+1)));
184  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
185
186  // Abbrev for TYPE_CODE_ARRAY.
187  Abbv = new BitCodeAbbrev();
188  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
189  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
190  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
191                            Log2_32_Ceil(VE.getTypes().size()+1)));
192  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
193
194  // Emit an entry count so the reader can reserve space.
195  TypeVals.push_back(TypeList.size());
196  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
197  TypeVals.clear();
198
199  // Loop over all of the types, emitting each in turn.
200  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
201    const Type *T = TypeList[i].first;
202    int AbbrevToUse = 0;
203    unsigned Code = 0;
204
205    switch (T->getTypeID()) {
206    default: llvm_unreachable("Unknown type!");
207    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
208    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
209    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
210    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
211    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
212    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
213    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
214    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
215    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
216    case Type::IntegerTyID:
217      // INTEGER: [width]
218      Code = bitc::TYPE_CODE_INTEGER;
219      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
220      break;
221    case Type::PointerTyID: {
222      const PointerType *PTy = cast<PointerType>(T);
223      // POINTER: [pointee type, address space]
224      Code = bitc::TYPE_CODE_POINTER;
225      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
226      unsigned AddressSpace = PTy->getAddressSpace();
227      TypeVals.push_back(AddressSpace);
228      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
229      break;
230    }
231    case Type::FunctionTyID: {
232      const FunctionType *FT = cast<FunctionType>(T);
233      // FUNCTION: [isvararg, attrid, retty, paramty x N]
234      Code = bitc::TYPE_CODE_FUNCTION;
235      TypeVals.push_back(FT->isVarArg());
236      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
237      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
238      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
239        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
240      AbbrevToUse = FunctionAbbrev;
241      break;
242    }
243    case Type::StructTyID: {
244      const StructType *ST = cast<StructType>(T);
245      // STRUCT: [ispacked, eltty x N]
246      Code = bitc::TYPE_CODE_STRUCT;
247      TypeVals.push_back(ST->isPacked());
248      // Output all of the element types.
249      for (StructType::element_iterator I = ST->element_begin(),
250           E = ST->element_end(); I != E; ++I)
251        TypeVals.push_back(VE.getTypeID(*I));
252      AbbrevToUse = StructAbbrev;
253      break;
254    }
255    case Type::ArrayTyID: {
256      const ArrayType *AT = cast<ArrayType>(T);
257      // ARRAY: [numelts, eltty]
258      Code = bitc::TYPE_CODE_ARRAY;
259      TypeVals.push_back(AT->getNumElements());
260      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
261      AbbrevToUse = ArrayAbbrev;
262      break;
263    }
264    case Type::VectorTyID: {
265      const VectorType *VT = cast<VectorType>(T);
266      // VECTOR [numelts, eltty]
267      Code = bitc::TYPE_CODE_VECTOR;
268      TypeVals.push_back(VT->getNumElements());
269      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
270      break;
271    }
272    }
273
274    // Emit the finished record.
275    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
276    TypeVals.clear();
277  }
278
279  Stream.ExitBlock();
280}
281
282static unsigned getEncodedLinkage(const GlobalValue *GV) {
283  switch (GV->getLinkage()) {
284  default: llvm_unreachable("Invalid linkage!");
285  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
286  case GlobalValue::ExternalLinkage:            return 0;
287  case GlobalValue::WeakAnyLinkage:             return 1;
288  case GlobalValue::AppendingLinkage:           return 2;
289  case GlobalValue::InternalLinkage:            return 3;
290  case GlobalValue::LinkOnceAnyLinkage:         return 4;
291  case GlobalValue::DLLImportLinkage:           return 5;
292  case GlobalValue::DLLExportLinkage:           return 6;
293  case GlobalValue::ExternalWeakLinkage:        return 7;
294  case GlobalValue::CommonLinkage:              return 8;
295  case GlobalValue::PrivateLinkage:             return 9;
296  case GlobalValue::WeakODRLinkage:             return 10;
297  case GlobalValue::LinkOnceODRLinkage:         return 11;
298  case GlobalValue::AvailableExternallyLinkage: return 12;
299  case GlobalValue::LinkerPrivateLinkage:       return 13;
300  }
301}
302
303static unsigned getEncodedVisibility(const GlobalValue *GV) {
304  switch (GV->getVisibility()) {
305  default: llvm_unreachable("Invalid visibility!");
306  case GlobalValue::DefaultVisibility:   return 0;
307  case GlobalValue::HiddenVisibility:    return 1;
308  case GlobalValue::ProtectedVisibility: return 2;
309  }
310}
311
312// Emit top-level description of module, including target triple, inline asm,
313// descriptors for global variables, and function prototype info.
314static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
315                            BitstreamWriter &Stream) {
316  // Emit the list of dependent libraries for the Module.
317  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
318    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
319
320  // Emit various pieces of data attached to a module.
321  if (!M->getTargetTriple().empty())
322    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
323                      0/*TODO*/, Stream);
324  if (!M->getDataLayout().empty())
325    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
326                      0/*TODO*/, Stream);
327  if (!M->getModuleInlineAsm().empty())
328    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
329                      0/*TODO*/, Stream);
330
331  // Emit information about sections and GC, computing how many there are. Also
332  // compute the maximum alignment value.
333  std::map<std::string, unsigned> SectionMap;
334  std::map<std::string, unsigned> GCMap;
335  unsigned MaxAlignment = 0;
336  unsigned MaxGlobalType = 0;
337  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
338       GV != E; ++GV) {
339    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
340    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
341
342    if (!GV->hasSection()) continue;
343    // Give section names unique ID's.
344    unsigned &Entry = SectionMap[GV->getSection()];
345    if (Entry != 0) continue;
346    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
347                      0/*TODO*/, Stream);
348    Entry = SectionMap.size();
349  }
350  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
351    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
352    if (F->hasSection()) {
353      // Give section names unique ID's.
354      unsigned &Entry = SectionMap[F->getSection()];
355      if (!Entry) {
356        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
357                          0/*TODO*/, Stream);
358        Entry = SectionMap.size();
359      }
360    }
361    if (F->hasGC()) {
362      // Same for GC names.
363      unsigned &Entry = GCMap[F->getGC()];
364      if (!Entry) {
365        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
366                          0/*TODO*/, Stream);
367        Entry = GCMap.size();
368      }
369    }
370  }
371
372  // Emit abbrev for globals, now that we know # sections and max alignment.
373  unsigned SimpleGVarAbbrev = 0;
374  if (!M->global_empty()) {
375    // Add an abbrev for common globals with no visibility or thread localness.
376    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
377    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
379                              Log2_32_Ceil(MaxGlobalType+1)));
380    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
381    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
382    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
383    if (MaxAlignment == 0)                                      // Alignment.
384      Abbv->Add(BitCodeAbbrevOp(0));
385    else {
386      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
387      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
388                               Log2_32_Ceil(MaxEncAlignment+1)));
389    }
390    if (SectionMap.empty())                                    // Section.
391      Abbv->Add(BitCodeAbbrevOp(0));
392    else
393      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
394                               Log2_32_Ceil(SectionMap.size()+1)));
395    // Don't bother emitting vis + thread local.
396    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
397  }
398
399  // Emit the global variable information.
400  SmallVector<unsigned, 64> Vals;
401  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
402       GV != E; ++GV) {
403    unsigned AbbrevToUse = 0;
404
405    // GLOBALVAR: [type, isconst, initid,
406    //             linkage, alignment, section, visibility, threadlocal]
407    Vals.push_back(VE.getTypeID(GV->getType()));
408    Vals.push_back(GV->isConstant());
409    Vals.push_back(GV->isDeclaration() ? 0 :
410                   (VE.getValueID(GV->getInitializer()) + 1));
411    Vals.push_back(getEncodedLinkage(GV));
412    Vals.push_back(Log2_32(GV->getAlignment())+1);
413    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
414    if (GV->isThreadLocal() ||
415        GV->getVisibility() != GlobalValue::DefaultVisibility) {
416      Vals.push_back(getEncodedVisibility(GV));
417      Vals.push_back(GV->isThreadLocal());
418    } else {
419      AbbrevToUse = SimpleGVarAbbrev;
420    }
421
422    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
423    Vals.clear();
424  }
425
426  // Emit the function proto information.
427  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
428    // FUNCTION:  [type, callingconv, isproto, paramattr,
429    //             linkage, alignment, section, visibility, gc]
430    Vals.push_back(VE.getTypeID(F->getType()));
431    Vals.push_back(F->getCallingConv());
432    Vals.push_back(F->isDeclaration());
433    Vals.push_back(getEncodedLinkage(F));
434    Vals.push_back(VE.getAttributeID(F->getAttributes()));
435    Vals.push_back(Log2_32(F->getAlignment())+1);
436    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
437    Vals.push_back(getEncodedVisibility(F));
438    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
439
440    unsigned AbbrevToUse = 0;
441    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
442    Vals.clear();
443  }
444
445
446  // Emit the alias information.
447  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
448       AI != E; ++AI) {
449    Vals.push_back(VE.getTypeID(AI->getType()));
450    Vals.push_back(VE.getValueID(AI->getAliasee()));
451    Vals.push_back(getEncodedLinkage(AI));
452    Vals.push_back(getEncodedVisibility(AI));
453    unsigned AbbrevToUse = 0;
454    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
455    Vals.clear();
456  }
457}
458
459static uint64_t GetOptimizationFlags(const Value *V) {
460  uint64_t Flags = 0;
461
462  if (const OverflowingBinaryOperator *OBO =
463        dyn_cast<OverflowingBinaryOperator>(V)) {
464    if (OBO->hasNoSignedWrap())
465      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
466    if (OBO->hasNoUnsignedWrap())
467      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
468  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
469    if (Div->isExact())
470      Flags |= 1 << bitc::SDIV_EXACT;
471  }
472
473  return Flags;
474}
475
476static void WriteMDNode(const MDNode *N,
477                        const ValueEnumerator &VE,
478                        BitstreamWriter &Stream,
479                        SmallVector<uint64_t, 64> &Record) {
480  for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
481    if (N->getElement(i)) {
482      Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
483      Record.push_back(VE.getValueID(N->getElement(i)));
484    } else {
485      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
486      Record.push_back(0);
487    }
488  }
489  Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
490  Record.clear();
491}
492
493static void WriteModuleMetadata(const ValueEnumerator &VE,
494                                BitstreamWriter &Stream) {
495  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
496  bool StartedMetadataBlock = false;
497  unsigned MDSAbbrev = 0;
498  SmallVector<uint64_t, 64> Record;
499  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
500
501    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
502      if (!StartedMetadataBlock) {
503        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
504        StartedMetadataBlock = true;
505      }
506      WriteMDNode(N, VE, Stream, Record);
507    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
508      if (!StartedMetadataBlock)  {
509        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
510
511        // Abbrev for METADATA_STRING.
512        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
513        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
514        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
515        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
516        MDSAbbrev = Stream.EmitAbbrev(Abbv);
517        StartedMetadataBlock = true;
518      }
519
520      // Code: [strchar x N]
521      Record.append(MDS->begin(), MDS->end());
522
523      // Emit the finished record.
524      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
525      Record.clear();
526    } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
527      if (!StartedMetadataBlock)  {
528        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
529        StartedMetadataBlock = true;
530      }
531
532      // Write name.
533      std::string Str = NMD->getNameStr();
534      const char *StrBegin = Str.c_str();
535      for (unsigned i = 0, e = Str.length(); i != e; ++i)
536        Record.push_back(StrBegin[i]);
537      Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
538      Record.clear();
539
540      // Write named metadata elements.
541      for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
542        if (NMD->getElement(i))
543          Record.push_back(VE.getValueID(NMD->getElement(i)));
544        else
545          Record.push_back(0);
546      }
547      Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
548      Record.clear();
549    }
550  }
551
552  if (StartedMetadataBlock)
553    Stream.ExitBlock();
554}
555
556static void WriteMetadataAttachment(const Function &F,
557                                    const ValueEnumerator &VE,
558                                    BitstreamWriter &Stream) {
559  bool StartedMetadataBlock = false;
560  SmallVector<uint64_t, 64> Record;
561
562  // Write metadata attachments
563  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
564  MetadataContext &TheMetadata = F.getContext().getMetadata();
565  typedef SmallVector<std::pair<unsigned, MDNode*>, 2> MDMapTy;
566  MDMapTy MDs;
567  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
568    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
569         I != E; ++I) {
570      MDs.clear();
571      TheMetadata.getMDs(I, MDs);
572      bool RecordedInstruction = false;
573      for (MDMapTy::const_iterator PI = MDs.begin(), PE = MDs.end();
574             PI != PE; ++PI) {
575        if (RecordedInstruction == false) {
576          Record.push_back(VE.getInstructionID(I));
577          RecordedInstruction = true;
578        }
579        Record.push_back(PI->first);
580        Record.push_back(VE.getValueID(PI->second));
581      }
582      if (!Record.empty()) {
583        if (!StartedMetadataBlock)  {
584          Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
585          StartedMetadataBlock = true;
586        }
587        Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
588        Record.clear();
589      }
590    }
591
592  if (StartedMetadataBlock)
593    Stream.ExitBlock();
594}
595
596static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
597  SmallVector<uint64_t, 64> Record;
598
599  // Write metadata kinds
600  // METADATA_KIND - [n x [id, name]]
601  MetadataContext &TheMetadata = M->getContext().getMetadata();
602  SmallVector<StringRef, 4> Names;
603  TheMetadata.getMDKindNames(Names);
604
605  assert(Names[0] == "" && "MDKind #0 is invalid");
606  if (Names.size() == 1) return;
607
608  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
609
610  for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
611    Record.push_back(MDKindID);
612    StringRef KName = Names[MDKindID];
613    Record.append(KName.begin(), KName.end());
614
615    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
616    Record.clear();
617  }
618
619  Stream.ExitBlock();
620}
621
622static void WriteConstants(unsigned FirstVal, unsigned LastVal,
623                           const ValueEnumerator &VE,
624                           BitstreamWriter &Stream, bool isGlobal) {
625  if (FirstVal == LastVal) return;
626
627  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
628
629  unsigned AggregateAbbrev = 0;
630  unsigned String8Abbrev = 0;
631  unsigned CString7Abbrev = 0;
632  unsigned CString6Abbrev = 0;
633  // If this is a constant pool for the module, emit module-specific abbrevs.
634  if (isGlobal) {
635    // Abbrev for CST_CODE_AGGREGATE.
636    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
637    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
638    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
639    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
640    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
641
642    // Abbrev for CST_CODE_STRING.
643    Abbv = new BitCodeAbbrev();
644    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
645    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
646    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
647    String8Abbrev = 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::Fixed, 7));
653    CString7Abbrev = Stream.EmitAbbrev(Abbv);
654    // Abbrev for CST_CODE_CSTRING.
655    Abbv = new BitCodeAbbrev();
656    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
657    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
658    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
659    CString6Abbrev = Stream.EmitAbbrev(Abbv);
660  }
661
662  SmallVector<uint64_t, 64> Record;
663
664  const ValueEnumerator::ValueList &Vals = VE.getValues();
665  const Type *LastTy = 0;
666  for (unsigned i = FirstVal; i != LastVal; ++i) {
667    const Value *V = Vals[i].first;
668    // If we need to switch types, do so now.
669    if (V->getType() != LastTy) {
670      LastTy = V->getType();
671      Record.push_back(VE.getTypeID(LastTy));
672      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
673                        CONSTANTS_SETTYPE_ABBREV);
674      Record.clear();
675    }
676
677    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
678      Record.push_back(unsigned(IA->hasSideEffects()) |
679                       unsigned(IA->isAlignStack()) << 1);
680
681      // Add the asm string.
682      const std::string &AsmStr = IA->getAsmString();
683      Record.push_back(AsmStr.size());
684      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
685        Record.push_back(AsmStr[i]);
686
687      // Add the constraint string.
688      const std::string &ConstraintStr = IA->getConstraintString();
689      Record.push_back(ConstraintStr.size());
690      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
691        Record.push_back(ConstraintStr[i]);
692      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
693      Record.clear();
694      continue;
695    }
696    const Constant *C = cast<Constant>(V);
697    unsigned Code = -1U;
698    unsigned AbbrevToUse = 0;
699    if (C->isNullValue()) {
700      Code = bitc::CST_CODE_NULL;
701    } else if (isa<UndefValue>(C)) {
702      Code = bitc::CST_CODE_UNDEF;
703    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
704      if (IV->getBitWidth() <= 64) {
705        int64_t V = IV->getSExtValue();
706        if (V >= 0)
707          Record.push_back(V << 1);
708        else
709          Record.push_back((-V << 1) | 1);
710        Code = bitc::CST_CODE_INTEGER;
711        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
712      } else {                             // Wide integers, > 64 bits in size.
713        // We have an arbitrary precision integer value to write whose
714        // bit width is > 64. However, in canonical unsigned integer
715        // format it is likely that the high bits are going to be zero.
716        // So, we only write the number of active words.
717        unsigned NWords = IV->getValue().getActiveWords();
718        const uint64_t *RawWords = IV->getValue().getRawData();
719        for (unsigned i = 0; i != NWords; ++i) {
720          int64_t V = RawWords[i];
721          if (V >= 0)
722            Record.push_back(V << 1);
723          else
724            Record.push_back((-V << 1) | 1);
725        }
726        Code = bitc::CST_CODE_WIDE_INTEGER;
727      }
728    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
729      Code = bitc::CST_CODE_FLOAT;
730      const Type *Ty = CFP->getType();
731      if (Ty->isFloatTy() || Ty->isDoubleTy()) {
732        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
733      } else if (Ty->isX86_FP80Ty()) {
734        // api needed to prevent premature destruction
735        // bits are not in the same order as a normal i80 APInt, compensate.
736        APInt api = CFP->getValueAPF().bitcastToAPInt();
737        const uint64_t *p = api.getRawData();
738        Record.push_back((p[1] << 48) | (p[0] >> 16));
739        Record.push_back(p[0] & 0xffffLL);
740      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
741        APInt api = CFP->getValueAPF().bitcastToAPInt();
742        const uint64_t *p = api.getRawData();
743        Record.push_back(p[0]);
744        Record.push_back(p[1]);
745      } else {
746        assert (0 && "Unknown FP type!");
747      }
748    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
749      const ConstantArray *CA = cast<ConstantArray>(C);
750      // Emit constant strings specially.
751      unsigned NumOps = CA->getNumOperands();
752      // If this is a null-terminated string, use the denser CSTRING encoding.
753      if (CA->getOperand(NumOps-1)->isNullValue()) {
754        Code = bitc::CST_CODE_CSTRING;
755        --NumOps;  // Don't encode the null, which isn't allowed by char6.
756      } else {
757        Code = bitc::CST_CODE_STRING;
758        AbbrevToUse = String8Abbrev;
759      }
760      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
761      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
762      for (unsigned i = 0; i != NumOps; ++i) {
763        unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
764        Record.push_back(V);
765        isCStr7 &= (V & 128) == 0;
766        if (isCStrChar6)
767          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
768      }
769
770      if (isCStrChar6)
771        AbbrevToUse = CString6Abbrev;
772      else if (isCStr7)
773        AbbrevToUse = CString7Abbrev;
774    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
775               isa<ConstantVector>(V)) {
776      Code = bitc::CST_CODE_AGGREGATE;
777      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
778        Record.push_back(VE.getValueID(C->getOperand(i)));
779      AbbrevToUse = AggregateAbbrev;
780    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
781      switch (CE->getOpcode()) {
782      default:
783        if (Instruction::isCast(CE->getOpcode())) {
784          Code = bitc::CST_CODE_CE_CAST;
785          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
786          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
787          Record.push_back(VE.getValueID(C->getOperand(0)));
788          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
789        } else {
790          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
791          Code = bitc::CST_CODE_CE_BINOP;
792          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
793          Record.push_back(VE.getValueID(C->getOperand(0)));
794          Record.push_back(VE.getValueID(C->getOperand(1)));
795          uint64_t Flags = GetOptimizationFlags(CE);
796          if (Flags != 0)
797            Record.push_back(Flags);
798        }
799        break;
800      case Instruction::GetElementPtr:
801        Code = bitc::CST_CODE_CE_GEP;
802        if (cast<GEPOperator>(C)->isInBounds())
803          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
804        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
805          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
806          Record.push_back(VE.getValueID(C->getOperand(i)));
807        }
808        break;
809      case Instruction::Select:
810        Code = bitc::CST_CODE_CE_SELECT;
811        Record.push_back(VE.getValueID(C->getOperand(0)));
812        Record.push_back(VE.getValueID(C->getOperand(1)));
813        Record.push_back(VE.getValueID(C->getOperand(2)));
814        break;
815      case Instruction::ExtractElement:
816        Code = bitc::CST_CODE_CE_EXTRACTELT;
817        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
818        Record.push_back(VE.getValueID(C->getOperand(0)));
819        Record.push_back(VE.getValueID(C->getOperand(1)));
820        break;
821      case Instruction::InsertElement:
822        Code = bitc::CST_CODE_CE_INSERTELT;
823        Record.push_back(VE.getValueID(C->getOperand(0)));
824        Record.push_back(VE.getValueID(C->getOperand(1)));
825        Record.push_back(VE.getValueID(C->getOperand(2)));
826        break;
827      case Instruction::ShuffleVector:
828        // If the return type and argument types are the same, this is a
829        // standard shufflevector instruction.  If the types are different,
830        // then the shuffle is widening or truncating the input vectors, and
831        // the argument type must also be encoded.
832        if (C->getType() == C->getOperand(0)->getType()) {
833          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
834        } else {
835          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
836          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
837        }
838        Record.push_back(VE.getValueID(C->getOperand(0)));
839        Record.push_back(VE.getValueID(C->getOperand(1)));
840        Record.push_back(VE.getValueID(C->getOperand(2)));
841        break;
842      case Instruction::ICmp:
843      case Instruction::FCmp:
844        Code = bitc::CST_CODE_CE_CMP;
845        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
846        Record.push_back(VE.getValueID(C->getOperand(0)));
847        Record.push_back(VE.getValueID(C->getOperand(1)));
848        Record.push_back(CE->getPredicate());
849        break;
850      }
851    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
852      assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
853             "Malformed blockaddress");
854      Code = bitc::CST_CODE_BLOCKADDRESS;
855      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
856      Record.push_back(VE.getValueID(BA->getFunction()));
857      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
858    } else {
859      llvm_unreachable("Unknown constant!");
860    }
861    Stream.EmitRecord(Code, Record, AbbrevToUse);
862    Record.clear();
863  }
864
865  Stream.ExitBlock();
866}
867
868static void WriteModuleConstants(const ValueEnumerator &VE,
869                                 BitstreamWriter &Stream) {
870  const ValueEnumerator::ValueList &Vals = VE.getValues();
871
872  // Find the first constant to emit, which is the first non-globalvalue value.
873  // We know globalvalues have been emitted by WriteModuleInfo.
874  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
875    if (!isa<GlobalValue>(Vals[i].first)) {
876      WriteConstants(i, Vals.size(), VE, Stream, true);
877      return;
878    }
879  }
880}
881
882/// PushValueAndType - The file has to encode both the value and type id for
883/// many values, because we need to know what type to create for forward
884/// references.  However, most operands are not forward references, so this type
885/// field is not needed.
886///
887/// This function adds V's value ID to Vals.  If the value ID is higher than the
888/// instruction ID, then it is a forward reference, and it also includes the
889/// type ID.
890static bool PushValueAndType(const Value *V, unsigned InstID,
891                             SmallVector<unsigned, 64> &Vals,
892                             ValueEnumerator &VE) {
893  unsigned ValID = VE.getValueID(V);
894  Vals.push_back(ValID);
895  if (ValID >= InstID) {
896    Vals.push_back(VE.getTypeID(V->getType()));
897    return true;
898  }
899  return false;
900}
901
902/// WriteInstruction - Emit an instruction to the specified stream.
903static void WriteInstruction(const Instruction &I, unsigned InstID,
904                             ValueEnumerator &VE, BitstreamWriter &Stream,
905                             SmallVector<unsigned, 64> &Vals) {
906  unsigned Code = 0;
907  unsigned AbbrevToUse = 0;
908  VE.setInstructionID(&I);
909  switch (I.getOpcode()) {
910  default:
911    if (Instruction::isCast(I.getOpcode())) {
912      Code = bitc::FUNC_CODE_INST_CAST;
913      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
914        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
915      Vals.push_back(VE.getTypeID(I.getType()));
916      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
917    } else {
918      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
919      Code = bitc::FUNC_CODE_INST_BINOP;
920      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
921        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
922      Vals.push_back(VE.getValueID(I.getOperand(1)));
923      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
924      uint64_t Flags = GetOptimizationFlags(&I);
925      if (Flags != 0) {
926        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
927          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
928        Vals.push_back(Flags);
929      }
930    }
931    break;
932
933  case Instruction::GetElementPtr:
934    Code = bitc::FUNC_CODE_INST_GEP;
935    if (cast<GEPOperator>(&I)->isInBounds())
936      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
937    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
938      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
939    break;
940  case Instruction::ExtractValue: {
941    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
942    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
943    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
944    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
945      Vals.push_back(*i);
946    break;
947  }
948  case Instruction::InsertValue: {
949    Code = bitc::FUNC_CODE_INST_INSERTVAL;
950    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
951    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
952    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
953    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
954      Vals.push_back(*i);
955    break;
956  }
957  case Instruction::Select:
958    Code = bitc::FUNC_CODE_INST_VSELECT;
959    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
960    Vals.push_back(VE.getValueID(I.getOperand(2)));
961    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
962    break;
963  case Instruction::ExtractElement:
964    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
965    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
966    Vals.push_back(VE.getValueID(I.getOperand(1)));
967    break;
968  case Instruction::InsertElement:
969    Code = bitc::FUNC_CODE_INST_INSERTELT;
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::ShuffleVector:
975    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
976    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
977    Vals.push_back(VE.getValueID(I.getOperand(1)));
978    Vals.push_back(VE.getValueID(I.getOperand(2)));
979    break;
980  case Instruction::ICmp:
981  case Instruction::FCmp:
982    // compare returning Int1Ty or vector of Int1Ty
983    Code = bitc::FUNC_CODE_INST_CMP2;
984    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
985    Vals.push_back(VE.getValueID(I.getOperand(1)));
986    Vals.push_back(cast<CmpInst>(I).getPredicate());
987    break;
988
989  case Instruction::Ret:
990    {
991      Code = bitc::FUNC_CODE_INST_RET;
992      unsigned NumOperands = I.getNumOperands();
993      if (NumOperands == 0)
994        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
995      else if (NumOperands == 1) {
996        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
997          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
998      } else {
999        for (unsigned i = 0, e = NumOperands; i != e; ++i)
1000          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1001      }
1002    }
1003    break;
1004  case Instruction::Br:
1005    {
1006      Code = bitc::FUNC_CODE_INST_BR;
1007      BranchInst &II = cast<BranchInst>(I);
1008      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1009      if (II.isConditional()) {
1010        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1011        Vals.push_back(VE.getValueID(II.getCondition()));
1012      }
1013    }
1014    break;
1015  case Instruction::Switch:
1016    Code = bitc::FUNC_CODE_INST_SWITCH;
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  case Instruction::IndirectBr:
1022    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1023    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1024    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1025      Vals.push_back(VE.getValueID(I.getOperand(i)));
1026    break;
1027
1028  case Instruction::Invoke: {
1029    const InvokeInst *II = cast<InvokeInst>(&I);
1030    const Value *Callee(II->getCalledValue());
1031    const PointerType *PTy = cast<PointerType>(Callee->getType());
1032    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1033    Code = bitc::FUNC_CODE_INST_INVOKE;
1034
1035    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1036    Vals.push_back(II->getCallingConv());
1037    Vals.push_back(VE.getValueID(II->getNormalDest()));
1038    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1039    PushValueAndType(Callee, InstID, Vals, VE);
1040
1041    // Emit value #'s for the fixed parameters.
1042    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1043      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1044
1045    // Emit type/value pairs for varargs params.
1046    if (FTy->isVarArg()) {
1047      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1048           i != e; ++i)
1049        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1050    }
1051    break;
1052  }
1053  case Instruction::Unwind:
1054    Code = bitc::FUNC_CODE_INST_UNWIND;
1055    break;
1056  case Instruction::Unreachable:
1057    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1058    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1059    break;
1060
1061  case Instruction::PHI:
1062    Code = bitc::FUNC_CODE_INST_PHI;
1063    Vals.push_back(VE.getTypeID(I.getType()));
1064    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1065      Vals.push_back(VE.getValueID(I.getOperand(i)));
1066    break;
1067
1068  case Instruction::Alloca:
1069    Code = bitc::FUNC_CODE_INST_ALLOCA;
1070    Vals.push_back(VE.getTypeID(I.getType()));
1071    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1072    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1073    break;
1074
1075  case Instruction::Load:
1076    Code = bitc::FUNC_CODE_INST_LOAD;
1077    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1078      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1079
1080    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1081    Vals.push_back(cast<LoadInst>(I).isVolatile());
1082    break;
1083  case Instruction::Store:
1084    Code = bitc::FUNC_CODE_INST_STORE2;
1085    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1086    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1087    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1088    Vals.push_back(cast<StoreInst>(I).isVolatile());
1089    break;
1090  case Instruction::Call: {
1091    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1092    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1093
1094    Code = bitc::FUNC_CODE_INST_CALL;
1095
1096    const CallInst *CI = cast<CallInst>(&I);
1097    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1098    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1099    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1100
1101    // Emit value #'s for the fixed parameters.
1102    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1103      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1104
1105    // Emit type/value pairs for varargs params.
1106    if (FTy->isVarArg()) {
1107      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1108      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1109           i != e; ++i)
1110        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1111    }
1112    break;
1113  }
1114  case Instruction::VAArg:
1115    Code = bitc::FUNC_CODE_INST_VAARG;
1116    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1117    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1118    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1119    break;
1120  }
1121
1122  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1123  Vals.clear();
1124}
1125
1126// Emit names for globals/functions etc.
1127static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1128                                  const ValueEnumerator &VE,
1129                                  BitstreamWriter &Stream) {
1130  if (VST.empty()) return;
1131  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1132
1133  // FIXME: Set up the abbrev, we know how many values there are!
1134  // FIXME: We know if the type names can use 7-bit ascii.
1135  SmallVector<unsigned, 64> NameVals;
1136
1137  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1138       SI != SE; ++SI) {
1139
1140    const ValueName &Name = *SI;
1141
1142    // Figure out the encoding to use for the name.
1143    bool is7Bit = true;
1144    bool isChar6 = true;
1145    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1146         C != E; ++C) {
1147      if (isChar6)
1148        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1149      if ((unsigned char)*C & 128) {
1150        is7Bit = false;
1151        break;  // don't bother scanning the rest.
1152      }
1153    }
1154
1155    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1156
1157    // VST_ENTRY:   [valueid, namechar x N]
1158    // VST_BBENTRY: [bbid, namechar x N]
1159    unsigned Code;
1160    if (isa<BasicBlock>(SI->getValue())) {
1161      Code = bitc::VST_CODE_BBENTRY;
1162      if (isChar6)
1163        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1164    } else {
1165      Code = bitc::VST_CODE_ENTRY;
1166      if (isChar6)
1167        AbbrevToUse = VST_ENTRY_6_ABBREV;
1168      else if (is7Bit)
1169        AbbrevToUse = VST_ENTRY_7_ABBREV;
1170    }
1171
1172    NameVals.push_back(VE.getValueID(SI->getValue()));
1173    for (const char *P = Name.getKeyData(),
1174         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1175      NameVals.push_back((unsigned char)*P);
1176
1177    // Emit the finished record.
1178    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1179    NameVals.clear();
1180  }
1181  Stream.ExitBlock();
1182}
1183
1184/// WriteFunction - Emit a function body to the module stream.
1185static void WriteFunction(const Function &F, ValueEnumerator &VE,
1186                          BitstreamWriter &Stream) {
1187  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1188  VE.incorporateFunction(F);
1189
1190  SmallVector<unsigned, 64> Vals;
1191
1192  // Emit the number of basic blocks, so the reader can create them ahead of
1193  // time.
1194  Vals.push_back(VE.getBasicBlocks().size());
1195  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1196  Vals.clear();
1197
1198  // If there are function-local constants, emit them now.
1199  unsigned CstStart, CstEnd;
1200  VE.getFunctionConstantRange(CstStart, CstEnd);
1201  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1202
1203  // Keep a running idea of what the instruction ID is.
1204  unsigned InstID = CstEnd;
1205
1206  // Finally, emit all the instructions, in order.
1207  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1208    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1209         I != E; ++I) {
1210      WriteInstruction(*I, InstID, VE, Stream, Vals);
1211      if (I->getType() != Type::getVoidTy(F.getContext()))
1212        ++InstID;
1213    }
1214
1215  // Emit names for all the instructions etc.
1216  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1217
1218  WriteMetadataAttachment(F, VE, Stream);
1219  VE.purgeFunction();
1220  Stream.ExitBlock();
1221}
1222
1223/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1224static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1225                                 const ValueEnumerator &VE,
1226                                 BitstreamWriter &Stream) {
1227  if (TST.empty()) return;
1228
1229  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1230
1231  // 7-bit fixed width VST_CODE_ENTRY strings.
1232  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1233  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1234  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1235                            Log2_32_Ceil(VE.getTypes().size()+1)));
1236  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1237  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1238  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1239
1240  SmallVector<unsigned, 64> NameVals;
1241
1242  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1243       TI != TE; ++TI) {
1244    // TST_ENTRY: [typeid, namechar x N]
1245    NameVals.push_back(VE.getTypeID(TI->second));
1246
1247    const std::string &Str = TI->first;
1248    bool is7Bit = true;
1249    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1250      NameVals.push_back((unsigned char)Str[i]);
1251      if (Str[i] & 128)
1252        is7Bit = false;
1253    }
1254
1255    // Emit the finished record.
1256    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1257    NameVals.clear();
1258  }
1259
1260  Stream.ExitBlock();
1261}
1262
1263// Emit blockinfo, which defines the standard abbreviations etc.
1264static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1265  // We only want to emit block info records for blocks that have multiple
1266  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1267  // blocks can defined their abbrevs inline.
1268  Stream.EnterBlockInfoBlock(2);
1269
1270  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1271    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1272    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1273    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1274    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1275    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1276    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1277                                   Abbv) != VST_ENTRY_8_ABBREV)
1278      llvm_unreachable("Unexpected abbrev ordering!");
1279  }
1280
1281  { // 7-bit fixed width VST_ENTRY strings.
1282    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1283    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1284    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1285    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1286    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1287    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1288                                   Abbv) != VST_ENTRY_7_ABBREV)
1289      llvm_unreachable("Unexpected abbrev ordering!");
1290  }
1291  { // 6-bit char6 VST_ENTRY strings.
1292    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1293    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1294    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1295    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1296    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1297    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1298                                   Abbv) != VST_ENTRY_6_ABBREV)
1299      llvm_unreachable("Unexpected abbrev ordering!");
1300  }
1301  { // 6-bit char6 VST_BBENTRY strings.
1302    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1303    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1304    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1305    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1306    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1307    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1308                                   Abbv) != VST_BBENTRY_6_ABBREV)
1309      llvm_unreachable("Unexpected abbrev ordering!");
1310  }
1311
1312
1313
1314  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1315    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1316    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1317    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1318                              Log2_32_Ceil(VE.getTypes().size()+1)));
1319    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1320                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1321      llvm_unreachable("Unexpected abbrev ordering!");
1322  }
1323
1324  { // INTEGER abbrev for CONSTANTS_BLOCK.
1325    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1326    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1327    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1328    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1329                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1330      llvm_unreachable("Unexpected abbrev ordering!");
1331  }
1332
1333  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1334    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1335    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1336    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1337    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1338                              Log2_32_Ceil(VE.getTypes().size()+1)));
1339    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1340
1341    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1342                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1343      llvm_unreachable("Unexpected abbrev ordering!");
1344  }
1345  { // NULL abbrev for CONSTANTS_BLOCK.
1346    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1347    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1348    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1349                                   Abbv) != CONSTANTS_NULL_Abbrev)
1350      llvm_unreachable("Unexpected abbrev ordering!");
1351  }
1352
1353  // FIXME: This should only use space for first class types!
1354
1355  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1356    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1357    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1358    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1359    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1360    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1361    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1362                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1363      llvm_unreachable("Unexpected abbrev ordering!");
1364  }
1365  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1366    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1367    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1368    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1369    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1370    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1371    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1372                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1373      llvm_unreachable("Unexpected abbrev ordering!");
1374  }
1375  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1376    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1377    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1379    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1380    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1381    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1382    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1383                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1384      llvm_unreachable("Unexpected abbrev ordering!");
1385  }
1386  { // INST_CAST abbrev for FUNCTION_BLOCK.
1387    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1388    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1389    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1390    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1391                              Log2_32_Ceil(VE.getTypes().size()+1)));
1392    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1393    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1394                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1395      llvm_unreachable("Unexpected abbrev ordering!");
1396  }
1397
1398  { // INST_RET abbrev for FUNCTION_BLOCK.
1399    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1400    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1401    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1402                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1403      llvm_unreachable("Unexpected abbrev ordering!");
1404  }
1405  { // INST_RET abbrev for FUNCTION_BLOCK.
1406    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1407    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1408    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1409    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1410                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1411      llvm_unreachable("Unexpected abbrev ordering!");
1412  }
1413  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1414    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1415    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1416    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1417                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1418      llvm_unreachable("Unexpected abbrev ordering!");
1419  }
1420
1421  Stream.ExitBlock();
1422}
1423
1424
1425/// WriteModule - Emit the specified module to the bitstream.
1426static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1427  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1428
1429  // Emit the version number if it is non-zero.
1430  if (CurVersion) {
1431    SmallVector<unsigned, 1> Vals;
1432    Vals.push_back(CurVersion);
1433    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1434  }
1435
1436  // Analyze the module, enumerating globals, functions, etc.
1437  ValueEnumerator VE(M);
1438
1439  // Emit blockinfo, which defines the standard abbreviations etc.
1440  WriteBlockInfo(VE, Stream);
1441
1442  // Emit information about parameter attributes.
1443  WriteAttributeTable(VE, Stream);
1444
1445  // Emit information describing all of the types in the module.
1446  WriteTypeTable(VE, Stream);
1447
1448  // Emit top-level description of module, including target triple, inline asm,
1449  // descriptors for global variables, and function prototype info.
1450  WriteModuleInfo(M, VE, Stream);
1451
1452  // Emit constants.
1453  WriteModuleConstants(VE, Stream);
1454
1455  // Emit metadata.
1456  WriteModuleMetadata(VE, Stream);
1457
1458  // Emit function bodies.
1459  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1460    if (!I->isDeclaration())
1461      WriteFunction(*I, VE, Stream);
1462
1463  // Emit metadata.
1464  WriteModuleMetadataStore(M, Stream);
1465
1466  // Emit the type symbol table information.
1467  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1468
1469  // Emit names for globals/functions etc.
1470  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1471
1472  Stream.ExitBlock();
1473}
1474
1475/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1476/// header and trailer to make it compatible with the system archiver.  To do
1477/// this we emit the following header, and then emit a trailer that pads the
1478/// file out to be a multiple of 16 bytes.
1479///
1480/// struct bc_header {
1481///   uint32_t Magic;         // 0x0B17C0DE
1482///   uint32_t Version;       // Version, currently always 0.
1483///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1484///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1485///   uint32_t CPUType;       // CPU specifier.
1486///   ... potentially more later ...
1487/// };
1488enum {
1489  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1490  DarwinBCHeaderSize = 5*4
1491};
1492
1493static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1494                               const std::string &TT) {
1495  unsigned CPUType = ~0U;
1496
1497  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1498  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1499  // specific constants here because they are implicitly part of the Darwin ABI.
1500  enum {
1501    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1502    DARWIN_CPU_TYPE_X86        = 7,
1503    DARWIN_CPU_TYPE_POWERPC    = 18
1504  };
1505
1506  if (TT.find("x86_64-") == 0)
1507    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1508  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1509           TT[4] == '-' && TT[1] - '3' < 6)
1510    CPUType = DARWIN_CPU_TYPE_X86;
1511  else if (TT.find("powerpc-") == 0)
1512    CPUType = DARWIN_CPU_TYPE_POWERPC;
1513  else if (TT.find("powerpc64-") == 0)
1514    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1515
1516  // Traditional Bitcode starts after header.
1517  unsigned BCOffset = DarwinBCHeaderSize;
1518
1519  Stream.Emit(0x0B17C0DE, 32);
1520  Stream.Emit(0         , 32);  // Version.
1521  Stream.Emit(BCOffset  , 32);
1522  Stream.Emit(0         , 32);  // Filled in later.
1523  Stream.Emit(CPUType   , 32);
1524}
1525
1526/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1527/// finalize the header.
1528static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1529  // Update the size field in the header.
1530  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1531
1532  // If the file is not a multiple of 16 bytes, insert dummy padding.
1533  while (BufferSize & 15) {
1534    Stream.Emit(0, 8);
1535    ++BufferSize;
1536  }
1537}
1538
1539
1540/// WriteBitcodeToFile - Write the specified module to the specified output
1541/// stream.
1542void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1543  std::vector<unsigned char> Buffer;
1544  BitstreamWriter Stream(Buffer);
1545
1546  Buffer.reserve(256*1024);
1547
1548  WriteBitcodeToStream( M, Stream );
1549
1550  // If writing to stdout, set binary mode.
1551  if (&llvm::outs() == &Out)
1552    sys::Program::ChangeStdoutToBinary();
1553
1554  // Write the generated bitstream to "Out".
1555  Out.write((char*)&Buffer.front(), Buffer.size());
1556
1557  // Make sure it hits disk now.
1558  Out.flush();
1559}
1560
1561/// WriteBitcodeToStream - Write the specified module to the specified output
1562/// stream.
1563void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1564  // If this is darwin, emit a file header and trailer if needed.
1565  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1566  if (isDarwin)
1567    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1568
1569  // Emit the file header.
1570  Stream.Emit((unsigned)'B', 8);
1571  Stream.Emit((unsigned)'C', 8);
1572  Stream.Emit(0x0, 4);
1573  Stream.Emit(0xC, 4);
1574  Stream.Emit(0xE, 4);
1575  Stream.Emit(0xD, 4);
1576
1577  // Emit the module.
1578  WriteModule(M, Stream);
1579
1580  if (isDarwin)
1581    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1582}
1583