BitcodeWriter.cpp revision c25e7581b9b8088910da31702d4ca21c4734c6d7 
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/MDNode.h"
23#include "llvm/Module.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/Streams.h"
29#include "llvm/Support/raw_ostream.h"
30#include "llvm/System/Program.h"
31using namespace llvm;
32
33/// These are manifest constants used by the bitcode writer. They do not need to
34/// be kept in sync with the reader, but need to be consistent within this file.
35enum {
36  CurVersion = 0,
37
38  // VALUE_SYMTAB_BLOCK abbrev id's.
39  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
40  VST_ENTRY_7_ABBREV,
41  VST_ENTRY_6_ABBREV,
42  VST_BBENTRY_6_ABBREV,
43
44  // CONSTANTS_BLOCK abbrev id's.
45  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
46  CONSTANTS_INTEGER_ABBREV,
47  CONSTANTS_CE_CAST_Abbrev,
48  CONSTANTS_NULL_Abbrev,
49
50  // FUNCTION_BLOCK abbrev id's.
51  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
52  FUNCTION_INST_BINOP_ABBREV,
53  FUNCTION_INST_CAST_ABBREV,
54  FUNCTION_INST_RET_VOID_ABBREV,
55  FUNCTION_INST_RET_VAL_ABBREV,
56  FUNCTION_INST_UNREACHABLE_ABBREV
57};
58
59
60static unsigned GetEncodedCastOpcode(unsigned Opcode) {
61  switch (Opcode) {
62  default: LLVM_UNREACHABLE("Unknown cast instruction!");
63  case Instruction::Trunc   : return bitc::CAST_TRUNC;
64  case Instruction::ZExt    : return bitc::CAST_ZEXT;
65  case Instruction::SExt    : return bitc::CAST_SEXT;
66  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
67  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
68  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
69  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
70  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
71  case Instruction::FPExt   : return bitc::CAST_FPEXT;
72  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
73  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
74  case Instruction::BitCast : return bitc::CAST_BITCAST;
75  }
76}
77
78static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
79  switch (Opcode) {
80  default: LLVM_UNREACHABLE("Unknown binary instruction!");
81  case Instruction::Add:
82  case Instruction::FAdd: return bitc::BINOP_ADD;
83  case Instruction::Sub:
84  case Instruction::FSub: return bitc::BINOP_SUB;
85  case Instruction::Mul:
86  case Instruction::FMul: return bitc::BINOP_MUL;
87  case Instruction::UDiv: return bitc::BINOP_UDIV;
88  case Instruction::FDiv:
89  case Instruction::SDiv: return bitc::BINOP_SDIV;
90  case Instruction::URem: return bitc::BINOP_UREM;
91  case Instruction::FRem:
92  case Instruction::SRem: return bitc::BINOP_SREM;
93  case Instruction::Shl:  return bitc::BINOP_SHL;
94  case Instruction::LShr: return bitc::BINOP_LSHR;
95  case Instruction::AShr: return bitc::BINOP_ASHR;
96  case Instruction::And:  return bitc::BINOP_AND;
97  case Instruction::Or:   return bitc::BINOP_OR;
98  case Instruction::Xor:  return bitc::BINOP_XOR;
99  }
100}
101
102
103
104static void WriteStringRecord(unsigned Code, const std::string &Str,
105                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
106  SmallVector<unsigned, 64> Vals;
107
108  // Code: [strchar x N]
109  for (unsigned i = 0, e = Str.size(); i != e; ++i)
110    Vals.push_back(Str[i]);
111
112  // Emit the finished record.
113  Stream.EmitRecord(Code, Vals, AbbrevToUse);
114}
115
116// Emit information about parameter attributes.
117static void WriteAttributeTable(const ValueEnumerator &VE,
118                                BitstreamWriter &Stream) {
119  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
120  if (Attrs.empty()) return;
121
122  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
123
124  SmallVector<uint64_t, 64> Record;
125  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
126    const AttrListPtr &A = Attrs[i];
127    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
128      const AttributeWithIndex &PAWI = A.getSlot(i);
129      Record.push_back(PAWI.Index);
130
131      // FIXME: remove in LLVM 3.0
132      // Store the alignment in the bitcode as a 16-bit raw value instead of a
133      // 5-bit log2 encoded value. Shift the bits above the alignment up by
134      // 11 bits.
135      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
136      if (PAWI.Attrs & Attribute::Alignment)
137        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
138      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
139
140      Record.push_back(FauxAttr);
141    }
142
143    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
144    Record.clear();
145  }
146
147  Stream.ExitBlock();
148}
149
150/// WriteTypeTable - Write out the type table for a module.
151static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
152  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
153
154  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
155  SmallVector<uint64_t, 64> TypeVals;
156
157  // Abbrev for TYPE_CODE_POINTER.
158  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
159  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
160  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
161                            Log2_32_Ceil(VE.getTypes().size()+1)));
162  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
163  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
164
165  // Abbrev for TYPE_CODE_FUNCTION.
166  Abbv = new BitCodeAbbrev();
167  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
168  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
169  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
171  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
172                            Log2_32_Ceil(VE.getTypes().size()+1)));
173  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
174
175  // Abbrev for TYPE_CODE_STRUCT.
176  Abbv = new BitCodeAbbrev();
177  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
178  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
179  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
181                            Log2_32_Ceil(VE.getTypes().size()+1)));
182  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
183
184  // Abbrev for TYPE_CODE_ARRAY.
185  Abbv = new BitCodeAbbrev();
186  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
187  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
188  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
189                            Log2_32_Ceil(VE.getTypes().size()+1)));
190  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
191
192  // Emit an entry count so the reader can reserve space.
193  TypeVals.push_back(TypeList.size());
194  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
195  TypeVals.clear();
196
197  // Loop over all of the types, emitting each in turn.
198  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
199    const Type *T = TypeList[i].first;
200    int AbbrevToUse = 0;
201    unsigned Code = 0;
202
203    switch (T->getTypeID()) {
204    default: LLVM_UNREACHABLE("Unknown type!");
205    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
206    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
207    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
208    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
209    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
210    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
211    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
212    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
213    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
214    case Type::IntegerTyID:
215      // INTEGER: [width]
216      Code = bitc::TYPE_CODE_INTEGER;
217      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
218      break;
219    case Type::PointerTyID: {
220      const PointerType *PTy = cast<PointerType>(T);
221      // POINTER: [pointee type, address space]
222      Code = bitc::TYPE_CODE_POINTER;
223      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
224      unsigned AddressSpace = PTy->getAddressSpace();
225      TypeVals.push_back(AddressSpace);
226      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
227      break;
228    }
229    case Type::FunctionTyID: {
230      const FunctionType *FT = cast<FunctionType>(T);
231      // FUNCTION: [isvararg, attrid, retty, paramty x N]
232      Code = bitc::TYPE_CODE_FUNCTION;
233      TypeVals.push_back(FT->isVarArg());
234      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
235      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
236      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
237        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
238      AbbrevToUse = FunctionAbbrev;
239      break;
240    }
241    case Type::StructTyID: {
242      const StructType *ST = cast<StructType>(T);
243      // STRUCT: [ispacked, eltty x N]
244      Code = bitc::TYPE_CODE_STRUCT;
245      TypeVals.push_back(ST->isPacked());
246      // Output all of the element types.
247      for (StructType::element_iterator I = ST->element_begin(),
248           E = ST->element_end(); I != E; ++I)
249        TypeVals.push_back(VE.getTypeID(*I));
250      AbbrevToUse = StructAbbrev;
251      break;
252    }
253    case Type::ArrayTyID: {
254      const ArrayType *AT = cast<ArrayType>(T);
255      // ARRAY: [numelts, eltty]
256      Code = bitc::TYPE_CODE_ARRAY;
257      TypeVals.push_back(AT->getNumElements());
258      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
259      AbbrevToUse = ArrayAbbrev;
260      break;
261    }
262    case Type::VectorTyID: {
263      const VectorType *VT = cast<VectorType>(T);
264      // VECTOR [numelts, eltty]
265      Code = bitc::TYPE_CODE_VECTOR;
266      TypeVals.push_back(VT->getNumElements());
267      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
268      break;
269    }
270    }
271
272    // Emit the finished record.
273    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
274    TypeVals.clear();
275  }
276
277  Stream.ExitBlock();
278}
279
280static unsigned getEncodedLinkage(const GlobalValue *GV) {
281  switch (GV->getLinkage()) {
282  default: LLVM_UNREACHABLE("Invalid linkage!");
283  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
284  case GlobalValue::ExternalLinkage:     return 0;
285  case GlobalValue::WeakAnyLinkage:      return 1;
286  case GlobalValue::AppendingLinkage:    return 2;
287  case GlobalValue::InternalLinkage:     return 3;
288  case GlobalValue::LinkOnceAnyLinkage:  return 4;
289  case GlobalValue::DLLImportLinkage:    return 5;
290  case GlobalValue::DLLExportLinkage:    return 6;
291  case GlobalValue::ExternalWeakLinkage: return 7;
292  case GlobalValue::CommonLinkage:       return 8;
293  case GlobalValue::PrivateLinkage:      return 9;
294  case GlobalValue::WeakODRLinkage:      return 10;
295  case GlobalValue::LinkOnceODRLinkage:  return 11;
296  case GlobalValue::AvailableExternallyLinkage:  return 12;
297  }
298}
299
300static unsigned getEncodedVisibility(const GlobalValue *GV) {
301  switch (GV->getVisibility()) {
302  default: LLVM_UNREACHABLE("Invalid visibility!");
303  case GlobalValue::DefaultVisibility:   return 0;
304  case GlobalValue::HiddenVisibility:    return 1;
305  case GlobalValue::ProtectedVisibility: return 2;
306  }
307}
308
309// Emit top-level description of module, including target triple, inline asm,
310// descriptors for global variables, and function prototype info.
311static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
312                            BitstreamWriter &Stream) {
313  // Emit the list of dependent libraries for the Module.
314  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
315    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
316
317  // Emit various pieces of data attached to a module.
318  if (!M->getTargetTriple().empty())
319    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
320                      0/*TODO*/, Stream);
321  if (!M->getDataLayout().empty())
322    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
323                      0/*TODO*/, Stream);
324  if (!M->getModuleInlineAsm().empty())
325    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
326                      0/*TODO*/, Stream);
327
328  // Emit information about sections and GC, computing how many there are. Also
329  // compute the maximum alignment value.
330  std::map<std::string, unsigned> SectionMap;
331  std::map<std::string, unsigned> GCMap;
332  unsigned MaxAlignment = 0;
333  unsigned MaxGlobalType = 0;
334  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
335       GV != E; ++GV) {
336    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
337    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
338
339    if (!GV->hasSection()) continue;
340    // Give section names unique ID's.
341    unsigned &Entry = SectionMap[GV->getSection()];
342    if (Entry != 0) continue;
343    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
344                      0/*TODO*/, Stream);
345    Entry = SectionMap.size();
346  }
347  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
348    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
349    if (F->hasSection()) {
350      // Give section names unique ID's.
351      unsigned &Entry = SectionMap[F->getSection()];
352      if (!Entry) {
353        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
354                          0/*TODO*/, Stream);
355        Entry = SectionMap.size();
356      }
357    }
358    if (F->hasGC()) {
359      // Same for GC names.
360      unsigned &Entry = GCMap[F->getGC()];
361      if (!Entry) {
362        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
363                          0/*TODO*/, Stream);
364        Entry = GCMap.size();
365      }
366    }
367  }
368
369  // Emit abbrev for globals, now that we know # sections and max alignment.
370  unsigned SimpleGVarAbbrev = 0;
371  if (!M->global_empty()) {
372    // Add an abbrev for common globals with no visibility or thread localness.
373    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
374    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
375    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
376                              Log2_32_Ceil(MaxGlobalType+1)));
377    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
379    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
380    if (MaxAlignment == 0)                                      // Alignment.
381      Abbv->Add(BitCodeAbbrevOp(0));
382    else {
383      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
384      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
385                               Log2_32_Ceil(MaxEncAlignment+1)));
386    }
387    if (SectionMap.empty())                                    // Section.
388      Abbv->Add(BitCodeAbbrevOp(0));
389    else
390      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
391                               Log2_32_Ceil(SectionMap.size()+1)));
392    // Don't bother emitting vis + thread local.
393    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
394  }
395
396  // Emit the global variable information.
397  SmallVector<unsigned, 64> Vals;
398  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
399       GV != E; ++GV) {
400    unsigned AbbrevToUse = 0;
401
402    // GLOBALVAR: [type, isconst, initid,
403    //             linkage, alignment, section, visibility, threadlocal]
404    Vals.push_back(VE.getTypeID(GV->getType()));
405    Vals.push_back(GV->isConstant());
406    Vals.push_back(GV->isDeclaration() ? 0 :
407                   (VE.getValueID(GV->getInitializer()) + 1));
408    Vals.push_back(getEncodedLinkage(GV));
409    Vals.push_back(Log2_32(GV->getAlignment())+1);
410    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
411    if (GV->isThreadLocal() ||
412        GV->getVisibility() != GlobalValue::DefaultVisibility) {
413      Vals.push_back(getEncodedVisibility(GV));
414      Vals.push_back(GV->isThreadLocal());
415    } else {
416      AbbrevToUse = SimpleGVarAbbrev;
417    }
418
419    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
420    Vals.clear();
421  }
422
423  // Emit the function proto information.
424  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
425    // FUNCTION:  [type, callingconv, isproto, paramattr,
426    //             linkage, alignment, section, visibility, gc]
427    Vals.push_back(VE.getTypeID(F->getType()));
428    Vals.push_back(F->getCallingConv());
429    Vals.push_back(F->isDeclaration());
430    Vals.push_back(getEncodedLinkage(F));
431    Vals.push_back(VE.getAttributeID(F->getAttributes()));
432    Vals.push_back(Log2_32(F->getAlignment())+1);
433    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
434    Vals.push_back(getEncodedVisibility(F));
435    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
436
437    unsigned AbbrevToUse = 0;
438    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
439    Vals.clear();
440  }
441
442
443  // Emit the alias information.
444  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
445       AI != E; ++AI) {
446    Vals.push_back(VE.getTypeID(AI->getType()));
447    Vals.push_back(VE.getValueID(AI->getAliasee()));
448    Vals.push_back(getEncodedLinkage(AI));
449    Vals.push_back(getEncodedVisibility(AI));
450    unsigned AbbrevToUse = 0;
451    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
452    Vals.clear();
453  }
454}
455
456
457static void WriteConstants(unsigned FirstVal, unsigned LastVal,
458                           const ValueEnumerator &VE,
459                           BitstreamWriter &Stream, bool isGlobal) {
460  if (FirstVal == LastVal) return;
461
462  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
463
464  unsigned AggregateAbbrev = 0;
465  unsigned String8Abbrev = 0;
466  unsigned CString7Abbrev = 0;
467  unsigned CString6Abbrev = 0;
468  unsigned MDString8Abbrev = 0;
469  unsigned MDString6Abbrev = 0;
470  // If this is a constant pool for the module, emit module-specific abbrevs.
471  if (isGlobal) {
472    // Abbrev for CST_CODE_AGGREGATE.
473    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
474    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
475    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
476    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
477    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
478
479    // Abbrev for CST_CODE_STRING.
480    Abbv = new BitCodeAbbrev();
481    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
482    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
483    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
484    String8Abbrev = Stream.EmitAbbrev(Abbv);
485    // Abbrev for CST_CODE_CSTRING.
486    Abbv = new BitCodeAbbrev();
487    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
488    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
489    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
490    CString7Abbrev = Stream.EmitAbbrev(Abbv);
491    // Abbrev for CST_CODE_CSTRING.
492    Abbv = new BitCodeAbbrev();
493    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
494    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
495    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
496    CString6Abbrev = Stream.EmitAbbrev(Abbv);
497
498    // Abbrev for CST_CODE_MDSTRING.
499    Abbv = new BitCodeAbbrev();
500    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
501    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
502    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
503    MDString8Abbrev = Stream.EmitAbbrev(Abbv);
504    // Abbrev for CST_CODE_MDSTRING.
505    Abbv = new BitCodeAbbrev();
506    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
507    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
508    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
509    MDString6Abbrev = Stream.EmitAbbrev(Abbv);
510  }
511
512  SmallVector<uint64_t, 64> Record;
513
514  const ValueEnumerator::ValueList &Vals = VE.getValues();
515  const Type *LastTy = 0;
516  for (unsigned i = FirstVal; i != LastVal; ++i) {
517    const Value *V = Vals[i].first;
518    // If we need to switch types, do so now.
519    if (V->getType() != LastTy) {
520      LastTy = V->getType();
521      Record.push_back(VE.getTypeID(LastTy));
522      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
523                        CONSTANTS_SETTYPE_ABBREV);
524      Record.clear();
525    }
526
527    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
528      Record.push_back(unsigned(IA->hasSideEffects()));
529
530      // Add the asm string.
531      const std::string &AsmStr = IA->getAsmString();
532      Record.push_back(AsmStr.size());
533      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
534        Record.push_back(AsmStr[i]);
535
536      // Add the constraint string.
537      const std::string &ConstraintStr = IA->getConstraintString();
538      Record.push_back(ConstraintStr.size());
539      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
540        Record.push_back(ConstraintStr[i]);
541      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
542      Record.clear();
543      continue;
544    }
545    const Constant *C = cast<Constant>(V);
546    unsigned Code = -1U;
547    unsigned AbbrevToUse = 0;
548    if (C->isNullValue()) {
549      Code = bitc::CST_CODE_NULL;
550    } else if (isa<UndefValue>(C)) {
551      Code = bitc::CST_CODE_UNDEF;
552    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
553      if (IV->getBitWidth() <= 64) {
554        int64_t V = IV->getSExtValue();
555        if (V >= 0)
556          Record.push_back(V << 1);
557        else
558          Record.push_back((-V << 1) | 1);
559        Code = bitc::CST_CODE_INTEGER;
560        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
561      } else {                             // Wide integers, > 64 bits in size.
562        // We have an arbitrary precision integer value to write whose
563        // bit width is > 64. However, in canonical unsigned integer
564        // format it is likely that the high bits are going to be zero.
565        // So, we only write the number of active words.
566        unsigned NWords = IV->getValue().getActiveWords();
567        const uint64_t *RawWords = IV->getValue().getRawData();
568        for (unsigned i = 0; i != NWords; ++i) {
569          int64_t V = RawWords[i];
570          if (V >= 0)
571            Record.push_back(V << 1);
572          else
573            Record.push_back((-V << 1) | 1);
574        }
575        Code = bitc::CST_CODE_WIDE_INTEGER;
576      }
577    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
578      Code = bitc::CST_CODE_FLOAT;
579      const Type *Ty = CFP->getType();
580      if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
581        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
582      } else if (Ty == Type::X86_FP80Ty) {
583        // api needed to prevent premature destruction
584        // bits are not in the same order as a normal i80 APInt, compensate.
585        APInt api = CFP->getValueAPF().bitcastToAPInt();
586        const uint64_t *p = api.getRawData();
587        Record.push_back((p[1] << 48) | (p[0] >> 16));
588        Record.push_back(p[0] & 0xffffLL);
589      } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
590        APInt api = CFP->getValueAPF().bitcastToAPInt();
591        const uint64_t *p = api.getRawData();
592        Record.push_back(p[0]);
593        Record.push_back(p[1]);
594      } else {
595        assert (0 && "Unknown FP type!");
596      }
597    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
598      // Emit constant strings specially.
599      unsigned NumOps = C->getNumOperands();
600      // If this is a null-terminated string, use the denser CSTRING encoding.
601      if (C->getOperand(NumOps-1)->isNullValue()) {
602        Code = bitc::CST_CODE_CSTRING;
603        --NumOps;  // Don't encode the null, which isn't allowed by char6.
604      } else {
605        Code = bitc::CST_CODE_STRING;
606        AbbrevToUse = String8Abbrev;
607      }
608      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
609      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
610      for (unsigned i = 0; i != NumOps; ++i) {
611        unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
612        Record.push_back(V);
613        isCStr7 &= (V & 128) == 0;
614        if (isCStrChar6)
615          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
616      }
617
618      if (isCStrChar6)
619        AbbrevToUse = CString6Abbrev;
620      else if (isCStr7)
621        AbbrevToUse = CString7Abbrev;
622    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
623               isa<ConstantVector>(V)) {
624      Code = bitc::CST_CODE_AGGREGATE;
625      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
626        Record.push_back(VE.getValueID(C->getOperand(i)));
627      AbbrevToUse = AggregateAbbrev;
628    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
629      switch (CE->getOpcode()) {
630      default:
631        if (Instruction::isCast(CE->getOpcode())) {
632          Code = bitc::CST_CODE_CE_CAST;
633          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
634          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
635          Record.push_back(VE.getValueID(C->getOperand(0)));
636          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
637        } else {
638          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
639          Code = bitc::CST_CODE_CE_BINOP;
640          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
641          Record.push_back(VE.getValueID(C->getOperand(0)));
642          Record.push_back(VE.getValueID(C->getOperand(1)));
643        }
644        break;
645      case Instruction::GetElementPtr:
646        Code = bitc::CST_CODE_CE_GEP;
647        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
648          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
649          Record.push_back(VE.getValueID(C->getOperand(i)));
650        }
651        break;
652      case Instruction::Select:
653        Code = bitc::CST_CODE_CE_SELECT;
654        Record.push_back(VE.getValueID(C->getOperand(0)));
655        Record.push_back(VE.getValueID(C->getOperand(1)));
656        Record.push_back(VE.getValueID(C->getOperand(2)));
657        break;
658      case Instruction::ExtractElement:
659        Code = bitc::CST_CODE_CE_EXTRACTELT;
660        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
661        Record.push_back(VE.getValueID(C->getOperand(0)));
662        Record.push_back(VE.getValueID(C->getOperand(1)));
663        break;
664      case Instruction::InsertElement:
665        Code = bitc::CST_CODE_CE_INSERTELT;
666        Record.push_back(VE.getValueID(C->getOperand(0)));
667        Record.push_back(VE.getValueID(C->getOperand(1)));
668        Record.push_back(VE.getValueID(C->getOperand(2)));
669        break;
670      case Instruction::ShuffleVector:
671        // If the return type and argument types are the same, this is a
672        // standard shufflevector instruction.  If the types are different,
673        // then the shuffle is widening or truncating the input vectors, and
674        // the argument type must also be encoded.
675        if (C->getType() == C->getOperand(0)->getType()) {
676          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
677        } else {
678          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
679          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
680        }
681        Record.push_back(VE.getValueID(C->getOperand(0)));
682        Record.push_back(VE.getValueID(C->getOperand(1)));
683        Record.push_back(VE.getValueID(C->getOperand(2)));
684        break;
685      case Instruction::ICmp:
686      case Instruction::FCmp:
687        Code = bitc::CST_CODE_CE_CMP;
688        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
689        Record.push_back(VE.getValueID(C->getOperand(0)));
690        Record.push_back(VE.getValueID(C->getOperand(1)));
691        Record.push_back(CE->getPredicate());
692        break;
693      }
694    } else if (const MDString *S = dyn_cast<MDString>(C)) {
695      Code = bitc::CST_CODE_MDSTRING;
696      AbbrevToUse = MDString6Abbrev;
697      for (unsigned i = 0, e = S->size(); i != e; ++i) {
698        char V = S->begin()[i];
699        Record.push_back(V);
700
701        if (!BitCodeAbbrevOp::isChar6(V))
702          AbbrevToUse = MDString8Abbrev;
703      }
704    } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
705      Code = bitc::CST_CODE_MDNODE;
706      for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
707        if (N->getElement(i)) {
708          Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
709          Record.push_back(VE.getValueID(N->getElement(i)));
710        } else {
711          Record.push_back(VE.getTypeID(Type::VoidTy));
712          Record.push_back(0);
713        }
714      }
715    } else {
716      LLVM_UNREACHABLE("Unknown constant!");
717    }
718    Stream.EmitRecord(Code, Record, AbbrevToUse);
719    Record.clear();
720  }
721
722  Stream.ExitBlock();
723}
724
725static void WriteModuleConstants(const ValueEnumerator &VE,
726                                 BitstreamWriter &Stream) {
727  const ValueEnumerator::ValueList &Vals = VE.getValues();
728
729  // Find the first constant to emit, which is the first non-globalvalue value.
730  // We know globalvalues have been emitted by WriteModuleInfo.
731  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
732    if (!isa<GlobalValue>(Vals[i].first)) {
733      WriteConstants(i, Vals.size(), VE, Stream, true);
734      return;
735    }
736  }
737}
738
739/// PushValueAndType - The file has to encode both the value and type id for
740/// many values, because we need to know what type to create for forward
741/// references.  However, most operands are not forward references, so this type
742/// field is not needed.
743///
744/// This function adds V's value ID to Vals.  If the value ID is higher than the
745/// instruction ID, then it is a forward reference, and it also includes the
746/// type ID.
747static bool PushValueAndType(const Value *V, unsigned InstID,
748                             SmallVector<unsigned, 64> &Vals,
749                             ValueEnumerator &VE) {
750  unsigned ValID = VE.getValueID(V);
751  Vals.push_back(ValID);
752  if (ValID >= InstID) {
753    Vals.push_back(VE.getTypeID(V->getType()));
754    return true;
755  }
756  return false;
757}
758
759/// WriteInstruction - Emit an instruction to the specified stream.
760static void WriteInstruction(const Instruction &I, unsigned InstID,
761                             ValueEnumerator &VE, BitstreamWriter &Stream,
762                             SmallVector<unsigned, 64> &Vals) {
763  unsigned Code = 0;
764  unsigned AbbrevToUse = 0;
765  switch (I.getOpcode()) {
766  default:
767    if (Instruction::isCast(I.getOpcode())) {
768      Code = bitc::FUNC_CODE_INST_CAST;
769      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
770        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
771      Vals.push_back(VE.getTypeID(I.getType()));
772      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
773    } else {
774      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
775      Code = bitc::FUNC_CODE_INST_BINOP;
776      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
777        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
778      Vals.push_back(VE.getValueID(I.getOperand(1)));
779      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
780    }
781    break;
782
783  case Instruction::GetElementPtr:
784    Code = bitc::FUNC_CODE_INST_GEP;
785    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
786      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
787    break;
788  case Instruction::ExtractValue: {
789    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
790    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
791    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
792    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
793      Vals.push_back(*i);
794    break;
795  }
796  case Instruction::InsertValue: {
797    Code = bitc::FUNC_CODE_INST_INSERTVAL;
798    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
799    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
800    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
801    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
802      Vals.push_back(*i);
803    break;
804  }
805  case Instruction::Select:
806    Code = bitc::FUNC_CODE_INST_VSELECT;
807    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
808    Vals.push_back(VE.getValueID(I.getOperand(2)));
809    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
810    break;
811  case Instruction::ExtractElement:
812    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
813    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
814    Vals.push_back(VE.getValueID(I.getOperand(1)));
815    break;
816  case Instruction::InsertElement:
817    Code = bitc::FUNC_CODE_INST_INSERTELT;
818    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
819    Vals.push_back(VE.getValueID(I.getOperand(1)));
820    Vals.push_back(VE.getValueID(I.getOperand(2)));
821    break;
822  case Instruction::ShuffleVector:
823    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
824    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
825    Vals.push_back(VE.getValueID(I.getOperand(1)));
826    Vals.push_back(VE.getValueID(I.getOperand(2)));
827    break;
828  case Instruction::ICmp:
829  case Instruction::FCmp:
830    // compare returning Int1Ty or vector of Int1Ty
831    Code = bitc::FUNC_CODE_INST_CMP2;
832    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
833    Vals.push_back(VE.getValueID(I.getOperand(1)));
834    Vals.push_back(cast<CmpInst>(I).getPredicate());
835    break;
836
837  case Instruction::Ret:
838    {
839      Code = bitc::FUNC_CODE_INST_RET;
840      unsigned NumOperands = I.getNumOperands();
841      if (NumOperands == 0)
842        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
843      else if (NumOperands == 1) {
844        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
845          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
846      } else {
847        for (unsigned i = 0, e = NumOperands; i != e; ++i)
848          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
849      }
850    }
851    break;
852  case Instruction::Br:
853    {
854      Code = bitc::FUNC_CODE_INST_BR;
855      BranchInst &II(cast<BranchInst>(I));
856      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
857      if (II.isConditional()) {
858        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
859        Vals.push_back(VE.getValueID(II.getCondition()));
860      }
861    }
862    break;
863  case Instruction::Switch:
864    Code = bitc::FUNC_CODE_INST_SWITCH;
865    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
866    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
867      Vals.push_back(VE.getValueID(I.getOperand(i)));
868    break;
869  case Instruction::Invoke: {
870    const InvokeInst *II = cast<InvokeInst>(&I);
871    const Value *Callee(II->getCalledValue());
872    const PointerType *PTy = cast<PointerType>(Callee->getType());
873    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
874    Code = bitc::FUNC_CODE_INST_INVOKE;
875
876    Vals.push_back(VE.getAttributeID(II->getAttributes()));
877    Vals.push_back(II->getCallingConv());
878    Vals.push_back(VE.getValueID(II->getNormalDest()));
879    Vals.push_back(VE.getValueID(II->getUnwindDest()));
880    PushValueAndType(Callee, InstID, Vals, VE);
881
882    // Emit value #'s for the fixed parameters.
883    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
884      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
885
886    // Emit type/value pairs for varargs params.
887    if (FTy->isVarArg()) {
888      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
889           i != e; ++i)
890        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
891    }
892    break;
893  }
894  case Instruction::Unwind:
895    Code = bitc::FUNC_CODE_INST_UNWIND;
896    break;
897  case Instruction::Unreachable:
898    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
899    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
900    break;
901
902  case Instruction::PHI:
903    Code = bitc::FUNC_CODE_INST_PHI;
904    Vals.push_back(VE.getTypeID(I.getType()));
905    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
906      Vals.push_back(VE.getValueID(I.getOperand(i)));
907    break;
908
909  case Instruction::Malloc:
910    Code = bitc::FUNC_CODE_INST_MALLOC;
911    Vals.push_back(VE.getTypeID(I.getType()));
912    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
913    Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
914    break;
915
916  case Instruction::Free:
917    Code = bitc::FUNC_CODE_INST_FREE;
918    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
919    break;
920
921  case Instruction::Alloca:
922    Code = bitc::FUNC_CODE_INST_ALLOCA;
923    Vals.push_back(VE.getTypeID(I.getType()));
924    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
925    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
926    break;
927
928  case Instruction::Load:
929    Code = bitc::FUNC_CODE_INST_LOAD;
930    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
931      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
932
933    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
934    Vals.push_back(cast<LoadInst>(I).isVolatile());
935    break;
936  case Instruction::Store:
937    Code = bitc::FUNC_CODE_INST_STORE2;
938    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
939    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
940    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
941    Vals.push_back(cast<StoreInst>(I).isVolatile());
942    break;
943  case Instruction::Call: {
944    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
945    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
946
947    Code = bitc::FUNC_CODE_INST_CALL;
948
949    const CallInst *CI = cast<CallInst>(&I);
950    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
951    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
952    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
953
954    // Emit value #'s for the fixed parameters.
955    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
956      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
957
958    // Emit type/value pairs for varargs params.
959    if (FTy->isVarArg()) {
960      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
961      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
962           i != e; ++i)
963        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
964    }
965    break;
966  }
967  case Instruction::VAArg:
968    Code = bitc::FUNC_CODE_INST_VAARG;
969    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
970    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
971    Vals.push_back(VE.getTypeID(I.getType())); // restype.
972    break;
973  }
974
975  Stream.EmitRecord(Code, Vals, AbbrevToUse);
976  Vals.clear();
977}
978
979// Emit names for globals/functions etc.
980static void WriteValueSymbolTable(const ValueSymbolTable &VST,
981                                  const ValueEnumerator &VE,
982                                  BitstreamWriter &Stream) {
983  if (VST.empty()) return;
984  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
985
986  // FIXME: Set up the abbrev, we know how many values there are!
987  // FIXME: We know if the type names can use 7-bit ascii.
988  SmallVector<unsigned, 64> NameVals;
989
990  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
991       SI != SE; ++SI) {
992
993    const ValueName &Name = *SI;
994
995    // Figure out the encoding to use for the name.
996    bool is7Bit = true;
997    bool isChar6 = true;
998    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
999         C != E; ++C) {
1000      if (isChar6)
1001        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1002      if ((unsigned char)*C & 128) {
1003        is7Bit = false;
1004        break;  // don't bother scanning the rest.
1005      }
1006    }
1007
1008    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1009
1010    // VST_ENTRY:   [valueid, namechar x N]
1011    // VST_BBENTRY: [bbid, namechar x N]
1012    unsigned Code;
1013    if (isa<BasicBlock>(SI->getValue())) {
1014      Code = bitc::VST_CODE_BBENTRY;
1015      if (isChar6)
1016        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1017    } else {
1018      Code = bitc::VST_CODE_ENTRY;
1019      if (isChar6)
1020        AbbrevToUse = VST_ENTRY_6_ABBREV;
1021      else if (is7Bit)
1022        AbbrevToUse = VST_ENTRY_7_ABBREV;
1023    }
1024
1025    NameVals.push_back(VE.getValueID(SI->getValue()));
1026    for (const char *P = Name.getKeyData(),
1027         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1028      NameVals.push_back((unsigned char)*P);
1029
1030    // Emit the finished record.
1031    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1032    NameVals.clear();
1033  }
1034  Stream.ExitBlock();
1035}
1036
1037/// WriteFunction - Emit a function body to the module stream.
1038static void WriteFunction(const Function &F, ValueEnumerator &VE,
1039                          BitstreamWriter &Stream) {
1040  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1041  VE.incorporateFunction(F);
1042
1043  SmallVector<unsigned, 64> Vals;
1044
1045  // Emit the number of basic blocks, so the reader can create them ahead of
1046  // time.
1047  Vals.push_back(VE.getBasicBlocks().size());
1048  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1049  Vals.clear();
1050
1051  // If there are function-local constants, emit them now.
1052  unsigned CstStart, CstEnd;
1053  VE.getFunctionConstantRange(CstStart, CstEnd);
1054  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1055
1056  // Keep a running idea of what the instruction ID is.
1057  unsigned InstID = CstEnd;
1058
1059  // Finally, emit all the instructions, in order.
1060  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1061    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1062         I != E; ++I) {
1063      WriteInstruction(*I, InstID, VE, Stream, Vals);
1064      if (I->getType() != Type::VoidTy)
1065        ++InstID;
1066    }
1067
1068  // Emit names for all the instructions etc.
1069  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1070
1071  VE.purgeFunction();
1072  Stream.ExitBlock();
1073}
1074
1075/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1076static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1077                                 const ValueEnumerator &VE,
1078                                 BitstreamWriter &Stream) {
1079  if (TST.empty()) return;
1080
1081  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1082
1083  // 7-bit fixed width VST_CODE_ENTRY strings.
1084  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1085  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1086  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1087                            Log2_32_Ceil(VE.getTypes().size()+1)));
1088  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1089  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1090  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1091
1092  SmallVector<unsigned, 64> NameVals;
1093
1094  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1095       TI != TE; ++TI) {
1096    // TST_ENTRY: [typeid, namechar x N]
1097    NameVals.push_back(VE.getTypeID(TI->second));
1098
1099    const std::string &Str = TI->first;
1100    bool is7Bit = true;
1101    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1102      NameVals.push_back((unsigned char)Str[i]);
1103      if (Str[i] & 128)
1104        is7Bit = false;
1105    }
1106
1107    // Emit the finished record.
1108    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1109    NameVals.clear();
1110  }
1111
1112  Stream.ExitBlock();
1113}
1114
1115// Emit blockinfo, which defines the standard abbreviations etc.
1116static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1117  // We only want to emit block info records for blocks that have multiple
1118  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1119  // blocks can defined their abbrevs inline.
1120  Stream.EnterBlockInfoBlock(2);
1121
1122  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1123    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1124    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1125    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1126    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1127    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1128    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1129                                   Abbv) != VST_ENTRY_8_ABBREV)
1130      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1131  }
1132
1133  { // 7-bit fixed width VST_ENTRY strings.
1134    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1135    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1136    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1137    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1138    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1139    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1140                                   Abbv) != VST_ENTRY_7_ABBREV)
1141      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1142  }
1143  { // 6-bit char6 VST_ENTRY strings.
1144    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1145    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1146    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1147    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1148    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1149    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1150                                   Abbv) != VST_ENTRY_6_ABBREV)
1151      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1152  }
1153  { // 6-bit char6 VST_BBENTRY strings.
1154    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1156    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1157    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1158    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1159    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1160                                   Abbv) != VST_BBENTRY_6_ABBREV)
1161      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1162  }
1163
1164
1165
1166  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1167    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1168    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1169    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1170                              Log2_32_Ceil(VE.getTypes().size()+1)));
1171    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1172                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1173      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1174  }
1175
1176  { // INTEGER abbrev for CONSTANTS_BLOCK.
1177    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1178    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1179    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1180    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1181                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1182      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1183  }
1184
1185  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1186    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1187    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1188    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1189    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1190                              Log2_32_Ceil(VE.getTypes().size()+1)));
1191    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1192
1193    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1194                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1195      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1196  }
1197  { // NULL abbrev for CONSTANTS_BLOCK.
1198    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1199    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1200    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1201                                   Abbv) != CONSTANTS_NULL_Abbrev)
1202      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1203  }
1204
1205  // FIXME: This should only use space for first class types!
1206
1207  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1208    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1209    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1210    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1211    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1212    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1213    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1214                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1215      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1216  }
1217  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1218    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1219    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1220    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1221    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1222    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1223    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1224                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1225      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1226  }
1227  { // INST_CAST abbrev for FUNCTION_BLOCK.
1228    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1229    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1230    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1231    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1232                              Log2_32_Ceil(VE.getTypes().size()+1)));
1233    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1234    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1235                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1236      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1237  }
1238
1239  { // INST_RET abbrev for FUNCTION_BLOCK.
1240    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1241    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1242    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1243                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1244      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1245  }
1246  { // INST_RET abbrev for FUNCTION_BLOCK.
1247    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1248    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1249    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1250    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1251                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1252      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1253  }
1254  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1255    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1256    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1257    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1258                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1259      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1260  }
1261
1262  Stream.ExitBlock();
1263}
1264
1265
1266/// WriteModule - Emit the specified module to the bitstream.
1267static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1268  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1269
1270  // Emit the version number if it is non-zero.
1271  if (CurVersion) {
1272    SmallVector<unsigned, 1> Vals;
1273    Vals.push_back(CurVersion);
1274    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1275  }
1276
1277  // Analyze the module, enumerating globals, functions, etc.
1278  ValueEnumerator VE(M);
1279
1280  // Emit blockinfo, which defines the standard abbreviations etc.
1281  WriteBlockInfo(VE, Stream);
1282
1283  // Emit information about parameter attributes.
1284  WriteAttributeTable(VE, Stream);
1285
1286  // Emit information describing all of the types in the module.
1287  WriteTypeTable(VE, Stream);
1288
1289  // Emit top-level description of module, including target triple, inline asm,
1290  // descriptors for global variables, and function prototype info.
1291  WriteModuleInfo(M, VE, Stream);
1292
1293  // Emit constants.
1294  WriteModuleConstants(VE, Stream);
1295
1296  // Emit function bodies.
1297  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1298    if (!I->isDeclaration())
1299      WriteFunction(*I, VE, Stream);
1300
1301  // Emit the type symbol table information.
1302  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1303
1304  // Emit names for globals/functions etc.
1305  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1306
1307  Stream.ExitBlock();
1308}
1309
1310/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1311/// header and trailer to make it compatible with the system archiver.  To do
1312/// this we emit the following header, and then emit a trailer that pads the
1313/// file out to be a multiple of 16 bytes.
1314///
1315/// struct bc_header {
1316///   uint32_t Magic;         // 0x0B17C0DE
1317///   uint32_t Version;       // Version, currently always 0.
1318///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1319///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1320///   uint32_t CPUType;       // CPU specifier.
1321///   ... potentially more later ...
1322/// };
1323enum {
1324  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1325  DarwinBCHeaderSize = 5*4
1326};
1327
1328static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1329                               const std::string &TT) {
1330  unsigned CPUType = ~0U;
1331
1332  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1333  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1334  // specific constants here because they are implicitly part of the Darwin ABI.
1335  enum {
1336    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1337    DARWIN_CPU_TYPE_X86        = 7,
1338    DARWIN_CPU_TYPE_POWERPC    = 18
1339  };
1340
1341  if (TT.find("x86_64-") == 0)
1342    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1343  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1344           TT[4] == '-' && TT[1] - '3' < 6)
1345    CPUType = DARWIN_CPU_TYPE_X86;
1346  else if (TT.find("powerpc-") == 0)
1347    CPUType = DARWIN_CPU_TYPE_POWERPC;
1348  else if (TT.find("powerpc64-") == 0)
1349    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1350
1351  // Traditional Bitcode starts after header.
1352  unsigned BCOffset = DarwinBCHeaderSize;
1353
1354  Stream.Emit(0x0B17C0DE, 32);
1355  Stream.Emit(0         , 32);  // Version.
1356  Stream.Emit(BCOffset  , 32);
1357  Stream.Emit(0         , 32);  // Filled in later.
1358  Stream.Emit(CPUType   , 32);
1359}
1360
1361/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1362/// finalize the header.
1363static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1364  // Update the size field in the header.
1365  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1366
1367  // If the file is not a multiple of 16 bytes, insert dummy padding.
1368  while (BufferSize & 15) {
1369    Stream.Emit(0, 8);
1370    ++BufferSize;
1371  }
1372}
1373
1374
1375/// WriteBitcodeToFile - Write the specified module to the specified output
1376/// stream.
1377void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1378  raw_os_ostream RawOut(Out);
1379  // If writing to stdout, set binary mode.
1380  if (llvm::cout == Out)
1381    sys::Program::ChangeStdoutToBinary();
1382  WriteBitcodeToFile(M, RawOut);
1383}
1384
1385/// WriteBitcodeToFile - Write the specified module to the specified output
1386/// stream.
1387void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1388  std::vector<unsigned char> Buffer;
1389  BitstreamWriter Stream(Buffer);
1390
1391  Buffer.reserve(256*1024);
1392
1393  WriteBitcodeToStream( M, Stream );
1394
1395  // If writing to stdout, set binary mode.
1396  if (&llvm::outs() == &Out)
1397    sys::Program::ChangeStdoutToBinary();
1398
1399  // Write the generated bitstream to "Out".
1400  Out.write((char*)&Buffer.front(), Buffer.size());
1401
1402  // Make sure it hits disk now.
1403  Out.flush();
1404}
1405
1406/// WriteBitcodeToStream - Write the specified module to the specified output
1407/// stream.
1408void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1409  // If this is darwin, emit a file header and trailer if needed.
1410  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1411  if (isDarwin)
1412    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1413
1414  // Emit the file header.
1415  Stream.Emit((unsigned)'B', 8);
1416  Stream.Emit((unsigned)'C', 8);
1417  Stream.Emit(0x0, 4);
1418  Stream.Emit(0xC, 4);
1419  Stream.Emit(0xE, 4);
1420  Stream.Emit(0xD, 4);
1421
1422  // Emit the module.
1423  WriteModule(M, Stream);
1424
1425  if (isDarwin)
1426    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1427}
1428