BitcodeWriter.cpp revision 0da7f6c8201b27938d3b9f048d71fd784cd1df9a 
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 "ReaderWriter_3_2.h"
15#include "ValueEnumerator.h"
16#include "llvm/ADT/Triple.h"
17#include "llvm/Bitcode/BitstreamWriter.h"
18#include "llvm/Bitcode/LLVMBitCodes.h"
19#include "llvm/IR/Constants.h"
20#include "llvm/IR/DerivedTypes.h"
21#include "llvm/IR/InlineAsm.h"
22#include "llvm/IR/Instructions.h"
23#include "llvm/IR/Module.h"
24#include "llvm/IR/Operator.h"
25#include "llvm/IR/ValueSymbolTable.h"
26#include "llvm/Support/CommandLine.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/MathExtras.h"
29#include "llvm/Support/Program.h"
30#include "llvm/Support/raw_ostream.h"
31#include <cctype>
32#include <map>
33using namespace llvm;
34
35static cl::opt<bool>
36EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
37                              cl::desc("Turn on experimental support for "
38                                       "use-list order preservation."),
39                              cl::init(false), cl::Hidden);
40
41/// These are manifest constants used by the bitcode writer. They do not need to
42/// be kept in sync with the reader, but need to be consistent within this file.
43enum {
44  CurVersion = 0,
45
46  // VALUE_SYMTAB_BLOCK abbrev id's.
47  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
48  VST_ENTRY_7_ABBREV,
49  VST_ENTRY_6_ABBREV,
50  VST_BBENTRY_6_ABBREV,
51
52  // CONSTANTS_BLOCK abbrev id's.
53  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
54  CONSTANTS_INTEGER_ABBREV,
55  CONSTANTS_CE_CAST_Abbrev,
56  CONSTANTS_NULL_Abbrev,
57
58  // FUNCTION_BLOCK abbrev id's.
59  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
60  FUNCTION_INST_BINOP_ABBREV,
61  FUNCTION_INST_BINOP_FLAGS_ABBREV,
62  FUNCTION_INST_CAST_ABBREV,
63  FUNCTION_INST_RET_VOID_ABBREV,
64  FUNCTION_INST_RET_VAL_ABBREV,
65  FUNCTION_INST_UNREACHABLE_ABBREV,
66
67  // SwitchInst Magic
68  SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
69};
70
71static unsigned GetEncodedCastOpcode(unsigned Opcode) {
72  switch (Opcode) {
73  default: llvm_unreachable("Unknown cast instruction!");
74  case Instruction::Trunc   : return bitc::CAST_TRUNC;
75  case Instruction::ZExt    : return bitc::CAST_ZEXT;
76  case Instruction::SExt    : return bitc::CAST_SEXT;
77  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
78  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
79  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
80  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
81  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
82  case Instruction::FPExt   : return bitc::CAST_FPEXT;
83  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
84  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
85  case Instruction::BitCast : return bitc::CAST_BITCAST;
86  }
87}
88
89static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
90  switch (Opcode) {
91  default: llvm_unreachable("Unknown binary instruction!");
92  case Instruction::Add:
93  case Instruction::FAdd: return bitc::BINOP_ADD;
94  case Instruction::Sub:
95  case Instruction::FSub: return bitc::BINOP_SUB;
96  case Instruction::Mul:
97  case Instruction::FMul: return bitc::BINOP_MUL;
98  case Instruction::UDiv: return bitc::BINOP_UDIV;
99  case Instruction::FDiv:
100  case Instruction::SDiv: return bitc::BINOP_SDIV;
101  case Instruction::URem: return bitc::BINOP_UREM;
102  case Instruction::FRem:
103  case Instruction::SRem: return bitc::BINOP_SREM;
104  case Instruction::Shl:  return bitc::BINOP_SHL;
105  case Instruction::LShr: return bitc::BINOP_LSHR;
106  case Instruction::AShr: return bitc::BINOP_ASHR;
107  case Instruction::And:  return bitc::BINOP_AND;
108  case Instruction::Or:   return bitc::BINOP_OR;
109  case Instruction::Xor:  return bitc::BINOP_XOR;
110  }
111}
112
113static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
114  switch (Op) {
115  default: llvm_unreachable("Unknown RMW operation!");
116  case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
117  case AtomicRMWInst::Add: return bitc::RMW_ADD;
118  case AtomicRMWInst::Sub: return bitc::RMW_SUB;
119  case AtomicRMWInst::And: return bitc::RMW_AND;
120  case AtomicRMWInst::Nand: return bitc::RMW_NAND;
121  case AtomicRMWInst::Or: return bitc::RMW_OR;
122  case AtomicRMWInst::Xor: return bitc::RMW_XOR;
123  case AtomicRMWInst::Max: return bitc::RMW_MAX;
124  case AtomicRMWInst::Min: return bitc::RMW_MIN;
125  case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
126  case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
127  }
128}
129
130static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
131  switch (Ordering) {
132  case NotAtomic: return bitc::ORDERING_NOTATOMIC;
133  case Unordered: return bitc::ORDERING_UNORDERED;
134  case Monotonic: return bitc::ORDERING_MONOTONIC;
135  case Acquire: return bitc::ORDERING_ACQUIRE;
136  case Release: return bitc::ORDERING_RELEASE;
137  case AcquireRelease: return bitc::ORDERING_ACQREL;
138  case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
139  }
140  llvm_unreachable("Invalid ordering");
141}
142
143static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
144  switch (SynchScope) {
145  case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
146  case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
147  }
148  llvm_unreachable("Invalid synch scope");
149}
150
151static void WriteStringRecord(unsigned Code, StringRef Str,
152                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
153  SmallVector<unsigned, 64> Vals;
154
155  // Code: [strchar x N]
156  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
157    if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
158      AbbrevToUse = 0;
159    Vals.push_back(Str[i]);
160  }
161
162  // Emit the finished record.
163  Stream.EmitRecord(Code, Vals, AbbrevToUse);
164}
165
166// Emit information about parameter attributes.
167static void WriteAttributeTable(const llvm_3_2::ValueEnumerator &VE,
168                                BitstreamWriter &Stream) {
169  const std::vector<AttributeSet> &Attrs = VE.getAttributes();
170  if (Attrs.empty()) return;
171
172  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
173
174  SmallVector<uint64_t, 64> Record;
175  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
176    const AttributeSet &A = Attrs[i];
177    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
178      Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
179
180    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
181    Record.clear();
182  }
183
184  Stream.ExitBlock();
185}
186
187/// WriteTypeTable - Write out the type table for a module.
188static void WriteTypeTable(const llvm_3_2::ValueEnumerator &VE,
189                           BitstreamWriter &Stream) {
190  const llvm_3_2::ValueEnumerator::TypeList &TypeList = VE.getTypes();
191
192  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
193  SmallVector<uint64_t, 64> TypeVals;
194
195  uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
196
197  // Abbrev for TYPE_CODE_POINTER.
198  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
199  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
200  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
201  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
202  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
203
204  // Abbrev for TYPE_CODE_FUNCTION.
205  Abbv = new BitCodeAbbrev();
206  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
207  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
208  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
209  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
210
211  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
212
213  // Abbrev for TYPE_CODE_STRUCT_ANON.
214  Abbv = new BitCodeAbbrev();
215  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
216  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
217  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
218  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
219
220  unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
221
222  // Abbrev for TYPE_CODE_STRUCT_NAME.
223  Abbv = new BitCodeAbbrev();
224  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
225  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
226  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
227  unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
228
229  // Abbrev for TYPE_CODE_STRUCT_NAMED.
230  Abbv = new BitCodeAbbrev();
231  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
232  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
233  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
234  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
235
236  unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
237
238  // Abbrev for TYPE_CODE_ARRAY.
239  Abbv = new BitCodeAbbrev();
240  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
241  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
242  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
243
244  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
245
246  // Emit an entry count so the reader can reserve space.
247  TypeVals.push_back(TypeList.size());
248  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
249  TypeVals.clear();
250
251  // Loop over all of the types, emitting each in turn.
252  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
253    Type *T = TypeList[i];
254    int AbbrevToUse = 0;
255    unsigned Code = 0;
256
257    switch (T->getTypeID()) {
258    default: llvm_unreachable("Unknown type!");
259    case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
260    case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
261    case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
262    case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
263    case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
264    case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
265    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
266    case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
267    case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
268    case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
269    case Type::IntegerTyID:
270      // INTEGER: [width]
271      Code = bitc::TYPE_CODE_INTEGER;
272      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
273      break;
274    case Type::PointerTyID: {
275      PointerType *PTy = cast<PointerType>(T);
276      // POINTER: [pointee type, address space]
277      Code = bitc::TYPE_CODE_POINTER;
278      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
279      unsigned AddressSpace = PTy->getAddressSpace();
280      TypeVals.push_back(AddressSpace);
281      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
282      break;
283    }
284    case Type::FunctionTyID: {
285      FunctionType *FT = cast<FunctionType>(T);
286      // FUNCTION: [isvararg, retty, paramty x N]
287      Code = bitc::TYPE_CODE_FUNCTION;
288      TypeVals.push_back(FT->isVarArg());
289      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
290      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
291        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
292      AbbrevToUse = FunctionAbbrev;
293      break;
294    }
295    case Type::StructTyID: {
296      StructType *ST = cast<StructType>(T);
297      // STRUCT: [ispacked, eltty x N]
298      TypeVals.push_back(ST->isPacked());
299      // Output all of the element types.
300      for (StructType::element_iterator I = ST->element_begin(),
301           E = ST->element_end(); I != E; ++I)
302        TypeVals.push_back(VE.getTypeID(*I));
303
304      if (ST->isLiteral()) {
305        Code = bitc::TYPE_CODE_STRUCT_ANON;
306        AbbrevToUse = StructAnonAbbrev;
307      } else {
308        if (ST->isOpaque()) {
309          Code = bitc::TYPE_CODE_OPAQUE;
310        } else {
311          Code = bitc::TYPE_CODE_STRUCT_NAMED;
312          AbbrevToUse = StructNamedAbbrev;
313        }
314
315        // Emit the name if it is present.
316        if (!ST->getName().empty())
317          WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
318                            StructNameAbbrev, Stream);
319      }
320      break;
321    }
322    case Type::ArrayTyID: {
323      ArrayType *AT = cast<ArrayType>(T);
324      // ARRAY: [numelts, eltty]
325      Code = bitc::TYPE_CODE_ARRAY;
326      TypeVals.push_back(AT->getNumElements());
327      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
328      AbbrevToUse = ArrayAbbrev;
329      break;
330    }
331    case Type::VectorTyID: {
332      VectorType *VT = cast<VectorType>(T);
333      // VECTOR [numelts, eltty]
334      Code = bitc::TYPE_CODE_VECTOR;
335      TypeVals.push_back(VT->getNumElements());
336      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
337      break;
338    }
339    }
340
341    // Emit the finished record.
342    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
343    TypeVals.clear();
344  }
345
346  Stream.ExitBlock();
347}
348
349static unsigned getEncodedLinkage(const GlobalValue *GV) {
350  switch (GV->getLinkage()) {
351  case GlobalValue::ExternalLinkage:                 return 0;
352  case GlobalValue::WeakAnyLinkage:                  return 1;
353  case GlobalValue::AppendingLinkage:                return 2;
354  case GlobalValue::InternalLinkage:                 return 3;
355  case GlobalValue::LinkOnceAnyLinkage:              return 4;
356  case GlobalValue::DLLImportLinkage:                return 5;
357  case GlobalValue::DLLExportLinkage:                return 6;
358  case GlobalValue::ExternalWeakLinkage:             return 7;
359  case GlobalValue::CommonLinkage:                   return 8;
360  case GlobalValue::PrivateLinkage:                  return 9;
361  case GlobalValue::WeakODRLinkage:                  return 10;
362  case GlobalValue::LinkOnceODRLinkage:              return 11;
363  case GlobalValue::AvailableExternallyLinkage:      return 12;
364  case GlobalValue::LinkerPrivateLinkage:            return 13;
365  case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
366  case GlobalValue::LinkOnceODRAutoHideLinkage:      return 15;
367  }
368  llvm_unreachable("Invalid linkage");
369}
370
371static unsigned getEncodedVisibility(const GlobalValue *GV) {
372  switch (GV->getVisibility()) {
373  case GlobalValue::DefaultVisibility:   return 0;
374  case GlobalValue::HiddenVisibility:    return 1;
375  case GlobalValue::ProtectedVisibility: return 2;
376  }
377  llvm_unreachable("Invalid visibility");
378}
379
380static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
381  switch (GV->getThreadLocalMode()) {
382    case GlobalVariable::NotThreadLocal:         return 0;
383    case GlobalVariable::GeneralDynamicTLSModel: return 1;
384    case GlobalVariable::LocalDynamicTLSModel:   return 2;
385    case GlobalVariable::InitialExecTLSModel:    return 3;
386    case GlobalVariable::LocalExecTLSModel:      return 4;
387  }
388  llvm_unreachable("Invalid TLS model");
389}
390
391// Emit top-level description of module, including target triple, inline asm,
392// descriptors for global variables, and function prototype info.
393static void WriteModuleInfo(const Module *M,
394                            const llvm_3_2::ValueEnumerator &VE,
395                            BitstreamWriter &Stream) {
396  // Emit various pieces of data attached to a module.
397  if (!M->getTargetTriple().empty())
398    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
399                      0/*TODO*/, Stream);
400  if (!M->getDataLayout().empty())
401    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
402                      0/*TODO*/, Stream);
403  if (!M->getModuleInlineAsm().empty())
404    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
405                      0/*TODO*/, Stream);
406
407  // Emit information about sections and GC, computing how many there are. Also
408  // compute the maximum alignment value.
409  std::map<std::string, unsigned> SectionMap;
410  std::map<std::string, unsigned> GCMap;
411  unsigned MaxAlignment = 0;
412  unsigned MaxGlobalType = 0;
413  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
414       GV != E; ++GV) {
415    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
416    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
417    if (GV->hasSection()) {
418      // Give section names unique ID's.
419      unsigned &Entry = SectionMap[GV->getSection()];
420      if (!Entry) {
421        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
422                          0/*TODO*/, Stream);
423        Entry = SectionMap.size();
424      }
425    }
426  }
427  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
428    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
429    if (F->hasSection()) {
430      // Give section names unique ID's.
431      unsigned &Entry = SectionMap[F->getSection()];
432      if (!Entry) {
433        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
434                          0/*TODO*/, Stream);
435        Entry = SectionMap.size();
436      }
437    }
438    if (F->hasGC()) {
439      // Same for GC names.
440      unsigned &Entry = GCMap[F->getGC()];
441      if (!Entry) {
442        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
443                          0/*TODO*/, Stream);
444        Entry = GCMap.size();
445      }
446    }
447  }
448
449  // Emit abbrev for globals, now that we know # sections and max alignment.
450  unsigned SimpleGVarAbbrev = 0;
451  if (!M->global_empty()) {
452    // Add an abbrev for common globals with no visibility or thread localness.
453    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
454    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
455    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
456                              Log2_32_Ceil(MaxGlobalType+1)));
457    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
458    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
459    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
460    if (MaxAlignment == 0)                                      // Alignment.
461      Abbv->Add(BitCodeAbbrevOp(0));
462    else {
463      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
464      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
465                               Log2_32_Ceil(MaxEncAlignment+1)));
466    }
467    if (SectionMap.empty())                                    // Section.
468      Abbv->Add(BitCodeAbbrevOp(0));
469    else
470      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
471                               Log2_32_Ceil(SectionMap.size()+1)));
472    // Don't bother emitting vis + thread local.
473    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
474  }
475
476  // Emit the global variable information.
477  SmallVector<unsigned, 64> Vals;
478  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
479       GV != E; ++GV) {
480    unsigned AbbrevToUse = 0;
481
482    // GLOBALVAR: [type, isconst, initid,
483    //             linkage, alignment, section, visibility, threadlocal,
484    //             unnamed_addr]
485    Vals.push_back(VE.getTypeID(GV->getType()));
486    Vals.push_back(GV->isConstant());
487    Vals.push_back(GV->isDeclaration() ? 0 :
488                   (VE.getValueID(GV->getInitializer()) + 1));
489    Vals.push_back(getEncodedLinkage(GV));
490    Vals.push_back(Log2_32(GV->getAlignment())+1);
491    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
492    if (GV->isThreadLocal() ||
493        GV->getVisibility() != GlobalValue::DefaultVisibility ||
494        GV->hasUnnamedAddr() || GV->isExternallyInitialized()) {
495      Vals.push_back(getEncodedVisibility(GV));
496      Vals.push_back(getEncodedThreadLocalMode(GV));
497      Vals.push_back(GV->hasUnnamedAddr());
498      Vals.push_back(GV->isExternallyInitialized());
499    } else {
500      AbbrevToUse = SimpleGVarAbbrev;
501    }
502
503    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
504    Vals.clear();
505  }
506
507  // Emit the function proto information.
508  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
509    // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
510    //             section, visibility, gc, unnamed_addr]
511    Vals.push_back(VE.getTypeID(F->getType()));
512    Vals.push_back(F->getCallingConv());
513    Vals.push_back(F->isDeclaration());
514    Vals.push_back(getEncodedLinkage(F));
515    Vals.push_back(VE.getAttributeID(F->getAttributes()));
516    Vals.push_back(Log2_32(F->getAlignment())+1);
517    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
518    Vals.push_back(getEncodedVisibility(F));
519    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
520    Vals.push_back(F->hasUnnamedAddr());
521
522    unsigned AbbrevToUse = 0;
523    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
524    Vals.clear();
525  }
526
527  // Emit the alias information.
528  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
529       AI != E; ++AI) {
530    // ALIAS: [alias type, aliasee val#, linkage, visibility]
531    Vals.push_back(VE.getTypeID(AI->getType()));
532    Vals.push_back(VE.getValueID(AI->getAliasee()));
533    Vals.push_back(getEncodedLinkage(AI));
534    Vals.push_back(getEncodedVisibility(AI));
535    unsigned AbbrevToUse = 0;
536    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
537    Vals.clear();
538  }
539}
540
541static uint64_t GetOptimizationFlags(const Value *V) {
542  uint64_t Flags = 0;
543
544  if (const OverflowingBinaryOperator *OBO =
545        dyn_cast<OverflowingBinaryOperator>(V)) {
546    if (OBO->hasNoSignedWrap())
547      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
548    if (OBO->hasNoUnsignedWrap())
549      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
550  } else if (const PossiblyExactOperator *PEO =
551               dyn_cast<PossiblyExactOperator>(V)) {
552    if (PEO->isExact())
553      Flags |= 1 << bitc::PEO_EXACT;
554  } else if (const FPMathOperator *FPMO =
555             dyn_cast<const FPMathOperator>(V)) {
556    // FIXME(srhines): We don't handle fast math in llvm-rs-cc today.
557    if (false) {
558      if (FPMO->hasUnsafeAlgebra())
559        Flags |= FastMathFlags::UnsafeAlgebra;
560      if (FPMO->hasNoNaNs())
561        Flags |= FastMathFlags::NoNaNs;
562      if (FPMO->hasNoInfs())
563        Flags |= FastMathFlags::NoInfs;
564      if (FPMO->hasNoSignedZeros())
565        Flags |= FastMathFlags::NoSignedZeros;
566      if (FPMO->hasAllowReciprocal())
567        Flags |= FastMathFlags::AllowReciprocal;
568    }
569  }
570
571  return Flags;
572}
573
574static void WriteMDNode(const MDNode *N,
575                        const llvm_3_2::ValueEnumerator &VE,
576                        BitstreamWriter &Stream,
577                        SmallVector<uint64_t, 64> &Record) {
578  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
579    if (N->getOperand(i)) {
580      Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
581      Record.push_back(VE.getValueID(N->getOperand(i)));
582    } else {
583      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
584      Record.push_back(0);
585    }
586  }
587  unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
588                                           bitc::METADATA_NODE;
589  Stream.EmitRecord(MDCode, Record, 0);
590  Record.clear();
591}
592
593static void WriteModuleMetadata(const Module *M,
594                                const llvm_3_2::ValueEnumerator &VE,
595                                BitstreamWriter &Stream) {
596  const llvm_3_2::ValueEnumerator::ValueList &Vals = VE.getMDValues();
597  bool StartedMetadataBlock = false;
598  unsigned MDSAbbrev = 0;
599  SmallVector<uint64_t, 64> Record;
600  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
601
602    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
603      if (!N->isFunctionLocal() || !N->getFunction()) {
604        if (!StartedMetadataBlock) {
605          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
606          StartedMetadataBlock = true;
607        }
608        WriteMDNode(N, VE, Stream, Record);
609      }
610    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
611      if (!StartedMetadataBlock)  {
612        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
613
614        // Abbrev for METADATA_STRING.
615        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
616        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
617        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
618        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
619        MDSAbbrev = Stream.EmitAbbrev(Abbv);
620        StartedMetadataBlock = true;
621      }
622
623      // Code: [strchar x N]
624      Record.append(MDS->begin(), MDS->end());
625
626      // Emit the finished record.
627      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
628      Record.clear();
629    }
630  }
631
632  // Write named metadata.
633  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
634       E = M->named_metadata_end(); I != E; ++I) {
635    const NamedMDNode *NMD = I;
636    if (!StartedMetadataBlock)  {
637      Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
638      StartedMetadataBlock = true;
639    }
640
641    // Write name.
642    StringRef Str = NMD->getName();
643    for (unsigned i = 0, e = Str.size(); i != e; ++i)
644      Record.push_back(Str[i]);
645    Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
646    Record.clear();
647
648    // Write named metadata operands.
649    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
650      Record.push_back(VE.getValueID(NMD->getOperand(i)));
651    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
652    Record.clear();
653  }
654
655  if (StartedMetadataBlock)
656    Stream.ExitBlock();
657}
658
659static void WriteFunctionLocalMetadata(const Function &F,
660                                       const llvm_3_2::ValueEnumerator &VE,
661                                       BitstreamWriter &Stream) {
662  bool StartedMetadataBlock = false;
663  SmallVector<uint64_t, 64> Record;
664  const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
665  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
666    if (const MDNode *N = Vals[i])
667      if (N->isFunctionLocal() && N->getFunction() == &F) {
668        if (!StartedMetadataBlock) {
669          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
670          StartedMetadataBlock = true;
671        }
672        WriteMDNode(N, VE, Stream, Record);
673      }
674
675  if (StartedMetadataBlock)
676    Stream.ExitBlock();
677}
678
679static void WriteMetadataAttachment(const Function &F,
680                                    const llvm_3_2::ValueEnumerator &VE,
681                                    BitstreamWriter &Stream) {
682  Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
683
684  SmallVector<uint64_t, 64> Record;
685
686  // Write metadata attachments
687  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
688  SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
689
690  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
691    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
692         I != E; ++I) {
693      MDs.clear();
694      I->getAllMetadataOtherThanDebugLoc(MDs);
695
696      // If no metadata, ignore instruction.
697      if (MDs.empty()) continue;
698
699      Record.push_back(VE.getInstructionID(I));
700
701      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
702        Record.push_back(MDs[i].first);
703        Record.push_back(VE.getValueID(MDs[i].second));
704      }
705      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
706      Record.clear();
707    }
708
709  Stream.ExitBlock();
710}
711
712static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
713  SmallVector<uint64_t, 64> Record;
714
715  // Write metadata kinds
716  // METADATA_KIND - [n x [id, name]]
717  SmallVector<StringRef, 4> Names;
718  M->getMDKindNames(Names);
719
720  if (Names.empty()) return;
721
722  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
723
724  for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
725    Record.push_back(MDKindID);
726    StringRef KName = Names[MDKindID];
727    Record.append(KName.begin(), KName.end());
728
729    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
730    Record.clear();
731  }
732
733  Stream.ExitBlock();
734}
735
736static void EmitAPInt(SmallVectorImpl<uint64_t> &Vals,
737                      unsigned &Code, unsigned &AbbrevToUse, const APInt &Val,
738                      bool EmitSizeForWideNumbers = false
739                      ) {
740  if (Val.getBitWidth() <= 64) {
741    uint64_t V = Val.getSExtValue();
742    if ((int64_t)V >= 0)
743      Vals.push_back(V << 1);
744    else
745      Vals.push_back((-V << 1) | 1);
746    Code = bitc::CST_CODE_INTEGER;
747    AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
748  } else {
749    // Wide integers, > 64 bits in size.
750    // We have an arbitrary precision integer value to write whose
751    // bit width is > 64. However, in canonical unsigned integer
752    // format it is likely that the high bits are going to be zero.
753    // So, we only write the number of active words.
754    unsigned NWords = Val.getActiveWords();
755
756    if (EmitSizeForWideNumbers)
757      Vals.push_back(NWords);
758
759    const uint64_t *RawWords = Val.getRawData();
760    for (unsigned i = 0; i != NWords; ++i) {
761      int64_t V = RawWords[i];
762      if (V >= 0)
763        Vals.push_back(V << 1);
764      else
765        Vals.push_back((-V << 1) | 1);
766    }
767    Code = bitc::CST_CODE_WIDE_INTEGER;
768  }
769}
770
771static void WriteConstants(unsigned FirstVal, unsigned LastVal,
772                           const llvm_3_2::ValueEnumerator &VE,
773                           BitstreamWriter &Stream, bool isGlobal) {
774  if (FirstVal == LastVal) return;
775
776  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
777
778  unsigned AggregateAbbrev = 0;
779  unsigned String8Abbrev = 0;
780  unsigned CString7Abbrev = 0;
781  unsigned CString6Abbrev = 0;
782  // If this is a constant pool for the module, emit module-specific abbrevs.
783  if (isGlobal) {
784    // Abbrev for CST_CODE_AGGREGATE.
785    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
786    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
787    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
788    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
789    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
790
791    // Abbrev for CST_CODE_STRING.
792    Abbv = new BitCodeAbbrev();
793    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
794    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
795    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
796    String8Abbrev = Stream.EmitAbbrev(Abbv);
797    // Abbrev for CST_CODE_CSTRING.
798    Abbv = new BitCodeAbbrev();
799    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
800    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
801    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
802    CString7Abbrev = Stream.EmitAbbrev(Abbv);
803    // Abbrev for CST_CODE_CSTRING.
804    Abbv = new BitCodeAbbrev();
805    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
806    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
807    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
808    CString6Abbrev = Stream.EmitAbbrev(Abbv);
809  }
810
811  SmallVector<uint64_t, 64> Record;
812
813  const llvm_3_2::ValueEnumerator::ValueList &Vals = VE.getValues();
814  Type *LastTy = 0;
815  for (unsigned i = FirstVal; i != LastVal; ++i) {
816    const Value *V = Vals[i].first;
817    // If we need to switch types, do so now.
818    if (V->getType() != LastTy) {
819      LastTy = V->getType();
820      Record.push_back(VE.getTypeID(LastTy));
821      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
822                        CONSTANTS_SETTYPE_ABBREV);
823      Record.clear();
824    }
825
826    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
827      Record.push_back(unsigned(IA->hasSideEffects()) |
828                       unsigned(IA->isAlignStack()) << 1 |
829                       unsigned(IA->getDialect()&1) << 2);
830
831      // Add the asm string.
832      const std::string &AsmStr = IA->getAsmString();
833      Record.push_back(AsmStr.size());
834      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
835        Record.push_back(AsmStr[i]);
836
837      // Add the constraint string.
838      const std::string &ConstraintStr = IA->getConstraintString();
839      Record.push_back(ConstraintStr.size());
840      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
841        Record.push_back(ConstraintStr[i]);
842      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
843      Record.clear();
844      continue;
845    }
846    const Constant *C = cast<Constant>(V);
847    unsigned Code = -1U;
848    unsigned AbbrevToUse = 0;
849    if (C->isNullValue()) {
850      Code = bitc::CST_CODE_NULL;
851    } else if (isa<UndefValue>(C)) {
852      Code = bitc::CST_CODE_UNDEF;
853    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
854      EmitAPInt(Record, Code, AbbrevToUse, IV->getValue());
855    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
856      Code = bitc::CST_CODE_FLOAT;
857      Type *Ty = CFP->getType();
858      if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
859        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
860      } else if (Ty->isX86_FP80Ty()) {
861        // api needed to prevent premature destruction
862        // bits are not in the same order as a normal i80 APInt, compensate.
863        APInt api = CFP->getValueAPF().bitcastToAPInt();
864        const uint64_t *p = api.getRawData();
865        Record.push_back((p[1] << 48) | (p[0] >> 16));
866        Record.push_back(p[0] & 0xffffLL);
867      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
868        APInt api = CFP->getValueAPF().bitcastToAPInt();
869        const uint64_t *p = api.getRawData();
870        Record.push_back(p[0]);
871        Record.push_back(p[1]);
872      } else {
873        assert (0 && "Unknown FP type!");
874      }
875    } else if (isa<ConstantDataSequential>(C) &&
876               cast<ConstantDataSequential>(C)->isString()) {
877      const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
878      // Emit constant strings specially.
879      unsigned NumElts = Str->getNumElements();
880      // If this is a null-terminated string, use the denser CSTRING encoding.
881      if (Str->isCString()) {
882        Code = bitc::CST_CODE_CSTRING;
883        --NumElts;  // Don't encode the null, which isn't allowed by char6.
884      } else {
885        Code = bitc::CST_CODE_STRING;
886        AbbrevToUse = String8Abbrev;
887      }
888      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
889      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
890      for (unsigned i = 0; i != NumElts; ++i) {
891        unsigned char V = Str->getElementAsInteger(i);
892        Record.push_back(V);
893        isCStr7 &= (V & 128) == 0;
894        if (isCStrChar6)
895          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
896      }
897
898      if (isCStrChar6)
899        AbbrevToUse = CString6Abbrev;
900      else if (isCStr7)
901        AbbrevToUse = CString7Abbrev;
902    } else if (const ConstantDataSequential *CDS =
903                  dyn_cast<ConstantDataSequential>(C)) {
904      Code = bitc::CST_CODE_DATA;
905      Type *EltTy = CDS->getType()->getElementType();
906      if (isa<IntegerType>(EltTy)) {
907        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
908          Record.push_back(CDS->getElementAsInteger(i));
909      } else if (EltTy->isFloatTy()) {
910        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
911          union { float F; uint32_t I; };
912          F = CDS->getElementAsFloat(i);
913          Record.push_back(I);
914        }
915      } else {
916        assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
917        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
918          union { double F; uint64_t I; };
919          F = CDS->getElementAsDouble(i);
920          Record.push_back(I);
921        }
922      }
923    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
924               isa<ConstantVector>(C)) {
925      Code = bitc::CST_CODE_AGGREGATE;
926      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
927        Record.push_back(VE.getValueID(C->getOperand(i)));
928      AbbrevToUse = AggregateAbbrev;
929    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
930      switch (CE->getOpcode()) {
931      default:
932        if (Instruction::isCast(CE->getOpcode())) {
933          Code = bitc::CST_CODE_CE_CAST;
934          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
935          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
936          Record.push_back(VE.getValueID(C->getOperand(0)));
937          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
938        } else {
939          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
940          Code = bitc::CST_CODE_CE_BINOP;
941          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
942          Record.push_back(VE.getValueID(C->getOperand(0)));
943          Record.push_back(VE.getValueID(C->getOperand(1)));
944          uint64_t Flags = GetOptimizationFlags(CE);
945          if (Flags != 0)
946            Record.push_back(Flags);
947        }
948        break;
949      case Instruction::GetElementPtr:
950        Code = bitc::CST_CODE_CE_GEP;
951        if (cast<GEPOperator>(C)->isInBounds())
952          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
953        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
954          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
955          Record.push_back(VE.getValueID(C->getOperand(i)));
956        }
957        break;
958      case Instruction::Select:
959        Code = bitc::CST_CODE_CE_SELECT;
960        Record.push_back(VE.getValueID(C->getOperand(0)));
961        Record.push_back(VE.getValueID(C->getOperand(1)));
962        Record.push_back(VE.getValueID(C->getOperand(2)));
963        break;
964      case Instruction::ExtractElement:
965        Code = bitc::CST_CODE_CE_EXTRACTELT;
966        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
967        Record.push_back(VE.getValueID(C->getOperand(0)));
968        Record.push_back(VE.getValueID(C->getOperand(1)));
969        break;
970      case Instruction::InsertElement:
971        Code = bitc::CST_CODE_CE_INSERTELT;
972        Record.push_back(VE.getValueID(C->getOperand(0)));
973        Record.push_back(VE.getValueID(C->getOperand(1)));
974        Record.push_back(VE.getValueID(C->getOperand(2)));
975        break;
976      case Instruction::ShuffleVector:
977        // If the return type and argument types are the same, this is a
978        // standard shufflevector instruction.  If the types are different,
979        // then the shuffle is widening or truncating the input vectors, and
980        // the argument type must also be encoded.
981        if (C->getType() == C->getOperand(0)->getType()) {
982          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
983        } else {
984          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
985          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
986        }
987        Record.push_back(VE.getValueID(C->getOperand(0)));
988        Record.push_back(VE.getValueID(C->getOperand(1)));
989        Record.push_back(VE.getValueID(C->getOperand(2)));
990        break;
991      case Instruction::ICmp:
992      case Instruction::FCmp:
993        Code = bitc::CST_CODE_CE_CMP;
994        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
995        Record.push_back(VE.getValueID(C->getOperand(0)));
996        Record.push_back(VE.getValueID(C->getOperand(1)));
997        Record.push_back(CE->getPredicate());
998        break;
999      }
1000    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1001      Code = bitc::CST_CODE_BLOCKADDRESS;
1002      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1003      Record.push_back(VE.getValueID(BA->getFunction()));
1004      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1005    } else {
1006#ifndef NDEBUG
1007      C->dump();
1008#endif
1009      llvm_unreachable("Unknown constant!");
1010    }
1011    Stream.EmitRecord(Code, Record, AbbrevToUse);
1012    Record.clear();
1013  }
1014
1015  Stream.ExitBlock();
1016}
1017
1018static void WriteModuleConstants(const llvm_3_2::ValueEnumerator &VE,
1019                                 BitstreamWriter &Stream) {
1020  const llvm_3_2::ValueEnumerator::ValueList &Vals = VE.getValues();
1021
1022  // Find the first constant to emit, which is the first non-globalvalue value.
1023  // We know globalvalues have been emitted by WriteModuleInfo.
1024  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1025    if (!isa<GlobalValue>(Vals[i].first)) {
1026      WriteConstants(i, Vals.size(), VE, Stream, true);
1027      return;
1028    }
1029  }
1030}
1031
1032/// PushValueAndType - The file has to encode both the value and type id for
1033/// many values, because we need to know what type to create for forward
1034/// references.  However, most operands are not forward references, so this type
1035/// field is not needed.
1036///
1037/// This function adds V's value ID to Vals.  If the value ID is higher than the
1038/// instruction ID, then it is a forward reference, and it also includes the
1039/// type ID.
1040static bool PushValueAndType(const Value *V, unsigned InstID,
1041                             SmallVector<unsigned, 64> &Vals,
1042                             llvm_3_2::ValueEnumerator &VE) {
1043  unsigned ValID = VE.getValueID(V);
1044  Vals.push_back(ValID);
1045  if (ValID >= InstID) {
1046    Vals.push_back(VE.getTypeID(V->getType()));
1047    return true;
1048  }
1049  return false;
1050}
1051
1052/// WriteInstruction - Emit an instruction to the specified stream.
1053static void WriteInstruction(const Instruction &I, unsigned InstID,
1054                             llvm_3_2::ValueEnumerator &VE,
1055                             BitstreamWriter &Stream,
1056                             SmallVector<unsigned, 64> &Vals) {
1057  unsigned Code = 0;
1058  unsigned AbbrevToUse = 0;
1059  VE.setInstructionID(&I);
1060  switch (I.getOpcode()) {
1061  default:
1062    if (Instruction::isCast(I.getOpcode())) {
1063      Code = bitc::FUNC_CODE_INST_CAST;
1064      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1065        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1066      Vals.push_back(VE.getTypeID(I.getType()));
1067      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1068    } else {
1069      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1070      Code = bitc::FUNC_CODE_INST_BINOP;
1071      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1072        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1073      Vals.push_back(VE.getValueID(I.getOperand(1)));
1074      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1075      uint64_t Flags = GetOptimizationFlags(&I);
1076      if (Flags != 0) {
1077        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1078          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1079        Vals.push_back(Flags);
1080      }
1081    }
1082    break;
1083
1084  case Instruction::GetElementPtr:
1085    Code = bitc::FUNC_CODE_INST_GEP;
1086    if (cast<GEPOperator>(&I)->isInBounds())
1087      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1088    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1089      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1090    break;
1091  case Instruction::ExtractValue: {
1092    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1093    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1094    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1095    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1096      Vals.push_back(*i);
1097    break;
1098  }
1099  case Instruction::InsertValue: {
1100    Code = bitc::FUNC_CODE_INST_INSERTVAL;
1101    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1102    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1103    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1104    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1105      Vals.push_back(*i);
1106    break;
1107  }
1108  case Instruction::Select:
1109    Code = bitc::FUNC_CODE_INST_VSELECT;
1110    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1111    Vals.push_back(VE.getValueID(I.getOperand(2)));
1112    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1113    break;
1114  case Instruction::ExtractElement:
1115    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1116    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1117    Vals.push_back(VE.getValueID(I.getOperand(1)));
1118    break;
1119  case Instruction::InsertElement:
1120    Code = bitc::FUNC_CODE_INST_INSERTELT;
1121    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1122    Vals.push_back(VE.getValueID(I.getOperand(1)));
1123    Vals.push_back(VE.getValueID(I.getOperand(2)));
1124    break;
1125  case Instruction::ShuffleVector:
1126    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1127    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1128    Vals.push_back(VE.getValueID(I.getOperand(1)));
1129    Vals.push_back(VE.getValueID(I.getOperand(2)));
1130    break;
1131  case Instruction::ICmp:
1132  case Instruction::FCmp:
1133    // compare returning Int1Ty or vector of Int1Ty
1134    Code = bitc::FUNC_CODE_INST_CMP2;
1135    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1136    Vals.push_back(VE.getValueID(I.getOperand(1)));
1137    Vals.push_back(cast<CmpInst>(I).getPredicate());
1138    break;
1139
1140  case Instruction::Ret:
1141    {
1142      Code = bitc::FUNC_CODE_INST_RET;
1143      unsigned NumOperands = I.getNumOperands();
1144      if (NumOperands == 0)
1145        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1146      else if (NumOperands == 1) {
1147        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1148          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1149      } else {
1150        for (unsigned i = 0, e = NumOperands; i != e; ++i)
1151          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1152      }
1153    }
1154    break;
1155  case Instruction::Br:
1156    {
1157      Code = bitc::FUNC_CODE_INST_BR;
1158      const BranchInst &II = cast<BranchInst>(I);
1159      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1160      if (II.isConditional()) {
1161        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1162        Vals.push_back(VE.getValueID(II.getCondition()));
1163      }
1164    }
1165    break;
1166  case Instruction::Switch:
1167    {
1168      // Redefine Vals, since here we need to use 64 bit values
1169      // explicitly to store large APInt numbers.
1170      SmallVector<uint64_t, 128> Vals64;
1171
1172      Code = bitc::FUNC_CODE_INST_SWITCH;
1173      const SwitchInst &SI = cast<SwitchInst>(I);
1174
1175      uint32_t SwitchRecordHeader = SI.hash() | (SWITCH_INST_MAGIC << 16);
1176      Vals64.push_back(SwitchRecordHeader);
1177
1178      Vals64.push_back(VE.getTypeID(SI.getCondition()->getType()));
1179      Vals64.push_back(VE.getValueID(SI.getCondition()));
1180      Vals64.push_back(VE.getValueID(SI.getDefaultDest()));
1181      Vals64.push_back(SI.getNumCases());
1182      for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1183           i != e; ++i) {
1184        const IntegersSubset& CaseRanges = i.getCaseValueEx();
1185        unsigned Code, Abbrev; // will unused.
1186
1187        if (CaseRanges.isSingleNumber()) {
1188          Vals64.push_back(1/*NumItems = 1*/);
1189          Vals64.push_back(true/*IsSingleNumber = true*/);
1190          EmitAPInt(Vals64, Code, Abbrev, CaseRanges.getSingleNumber(0), true);
1191        } else {
1192
1193          Vals64.push_back(CaseRanges.getNumItems());
1194
1195          if (CaseRanges.isSingleNumbersOnly()) {
1196            for (unsigned ri = 0, rn = CaseRanges.getNumItems();
1197                 ri != rn; ++ri) {
1198
1199              Vals64.push_back(true/*IsSingleNumber = true*/);
1200
1201              EmitAPInt(Vals64, Code, Abbrev,
1202                        CaseRanges.getSingleNumber(ri), true);
1203            }
1204          } else
1205            for (unsigned ri = 0, rn = CaseRanges.getNumItems();
1206                 ri != rn; ++ri) {
1207              IntegersSubset::Range r = CaseRanges.getItem(ri);
1208              bool IsSingleNumber = CaseRanges.isSingleNumber(ri);
1209
1210              Vals64.push_back(IsSingleNumber);
1211
1212              EmitAPInt(Vals64, Code, Abbrev, r.getLow(), true);
1213              if (!IsSingleNumber)
1214                EmitAPInt(Vals64, Code, Abbrev, r.getHigh(), true);
1215            }
1216        }
1217        Vals64.push_back(VE.getValueID(i.getCaseSuccessor()));
1218      }
1219
1220      Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1221
1222      // Also do expected action - clear external Vals collection:
1223      Vals.clear();
1224      return;
1225    }
1226    break;
1227  case Instruction::IndirectBr:
1228    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1229    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1230    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1231      Vals.push_back(VE.getValueID(I.getOperand(i)));
1232    break;
1233
1234  case Instruction::Invoke: {
1235    const InvokeInst *II = cast<InvokeInst>(&I);
1236    const Value *Callee(II->getCalledValue());
1237    PointerType *PTy = cast<PointerType>(Callee->getType());
1238    FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1239    Code = bitc::FUNC_CODE_INST_INVOKE;
1240
1241    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1242    Vals.push_back(II->getCallingConv());
1243    Vals.push_back(VE.getValueID(II->getNormalDest()));
1244    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1245    PushValueAndType(Callee, InstID, Vals, VE);
1246
1247    // Emit value #'s for the fixed parameters.
1248    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1249      Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1250
1251    // Emit type/value pairs for varargs params.
1252    if (FTy->isVarArg()) {
1253      for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1254           i != e; ++i)
1255        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1256    }
1257    break;
1258  }
1259  case Instruction::Resume:
1260    Code = bitc::FUNC_CODE_INST_RESUME;
1261    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1262    break;
1263  case Instruction::Unreachable:
1264    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1265    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1266    break;
1267
1268  case Instruction::PHI: {
1269    const PHINode &PN = cast<PHINode>(I);
1270    Code = bitc::FUNC_CODE_INST_PHI;
1271    Vals.push_back(VE.getTypeID(PN.getType()));
1272    for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1273      Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1274      Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1275    }
1276    break;
1277  }
1278
1279  case Instruction::LandingPad: {
1280    const LandingPadInst &LP = cast<LandingPadInst>(I);
1281    Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1282    Vals.push_back(VE.getTypeID(LP.getType()));
1283    PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1284    Vals.push_back(LP.isCleanup());
1285    Vals.push_back(LP.getNumClauses());
1286    for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1287      if (LP.isCatch(I))
1288        Vals.push_back(LandingPadInst::Catch);
1289      else
1290        Vals.push_back(LandingPadInst::Filter);
1291      PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1292    }
1293    break;
1294  }
1295
1296  case Instruction::Alloca:
1297    Code = bitc::FUNC_CODE_INST_ALLOCA;
1298    Vals.push_back(VE.getTypeID(I.getType()));
1299    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1300    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1301    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1302    break;
1303
1304  case Instruction::Load:
1305    if (cast<LoadInst>(I).isAtomic()) {
1306      Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1307      PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1308    } else {
1309      Code = bitc::FUNC_CODE_INST_LOAD;
1310      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1311        AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1312    }
1313    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1314    Vals.push_back(cast<LoadInst>(I).isVolatile());
1315    if (cast<LoadInst>(I).isAtomic()) {
1316      Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1317      Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1318    }
1319    break;
1320  case Instruction::Store:
1321    if (cast<StoreInst>(I).isAtomic())
1322      Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1323    else
1324      Code = bitc::FUNC_CODE_INST_STORE;
1325    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1326    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1327    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1328    Vals.push_back(cast<StoreInst>(I).isVolatile());
1329    if (cast<StoreInst>(I).isAtomic()) {
1330      Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1331      Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1332    }
1333    break;
1334  case Instruction::AtomicCmpXchg:
1335    Code = bitc::FUNC_CODE_INST_CMPXCHG;
1336    PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1337    Vals.push_back(VE.getValueID(I.getOperand(1)));       // cmp.
1338    Vals.push_back(VE.getValueID(I.getOperand(2)));       // newval.
1339    Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1340    Vals.push_back(GetEncodedOrdering(
1341                     cast<AtomicCmpXchgInst>(I).getOrdering()));
1342    Vals.push_back(GetEncodedSynchScope(
1343                     cast<AtomicCmpXchgInst>(I).getSynchScope()));
1344    break;
1345  case Instruction::AtomicRMW:
1346    Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1347    PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1348    Vals.push_back(VE.getValueID(I.getOperand(1)));       // val.
1349    Vals.push_back(GetEncodedRMWOperation(
1350                     cast<AtomicRMWInst>(I).getOperation()));
1351    Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1352    Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1353    Vals.push_back(GetEncodedSynchScope(
1354                     cast<AtomicRMWInst>(I).getSynchScope()));
1355    break;
1356  case Instruction::Fence:
1357    Code = bitc::FUNC_CODE_INST_FENCE;
1358    Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1359    Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1360    break;
1361  case Instruction::Call: {
1362    const CallInst &CI = cast<CallInst>(I);
1363    PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1364    FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1365
1366    Code = bitc::FUNC_CODE_INST_CALL;
1367
1368    Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1369    Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1370    PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1371
1372    // Emit value #'s for the fixed parameters.
1373    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1374      Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1375
1376    // Emit type/value pairs for varargs params.
1377    if (FTy->isVarArg()) {
1378      for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1379           i != e; ++i)
1380        PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1381    }
1382    break;
1383  }
1384  case Instruction::VAArg:
1385    Code = bitc::FUNC_CODE_INST_VAARG;
1386    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1387    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1388    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1389    break;
1390  }
1391
1392  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1393  Vals.clear();
1394}
1395
1396// Emit names for globals/functions etc.
1397static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1398                                  const llvm_3_2::ValueEnumerator &VE,
1399                                  BitstreamWriter &Stream) {
1400  if (VST.empty()) return;
1401  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1402
1403  // FIXME: Set up the abbrev, we know how many values there are!
1404  // FIXME: We know if the type names can use 7-bit ascii.
1405  SmallVector<unsigned, 64> NameVals;
1406
1407  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1408       SI != SE; ++SI) {
1409
1410    const ValueName &Name = *SI;
1411
1412    // Figure out the encoding to use for the name.
1413    bool is7Bit = true;
1414    bool isChar6 = true;
1415    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1416         C != E; ++C) {
1417      if (isChar6)
1418        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1419      if ((unsigned char)*C & 128) {
1420        is7Bit = false;
1421        break;  // don't bother scanning the rest.
1422      }
1423    }
1424
1425    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1426
1427    // VST_ENTRY:   [valueid, namechar x N]
1428    // VST_BBENTRY: [bbid, namechar x N]
1429    unsigned Code;
1430    if (isa<BasicBlock>(SI->getValue())) {
1431      Code = bitc::VST_CODE_BBENTRY;
1432      if (isChar6)
1433        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1434    } else {
1435      Code = bitc::VST_CODE_ENTRY;
1436      if (isChar6)
1437        AbbrevToUse = VST_ENTRY_6_ABBREV;
1438      else if (is7Bit)
1439        AbbrevToUse = VST_ENTRY_7_ABBREV;
1440    }
1441
1442    NameVals.push_back(VE.getValueID(SI->getValue()));
1443    for (const char *P = Name.getKeyData(),
1444         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1445      NameVals.push_back((unsigned char)*P);
1446
1447    // Emit the finished record.
1448    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1449    NameVals.clear();
1450  }
1451  Stream.ExitBlock();
1452}
1453
1454/// WriteFunction - Emit a function body to the module stream.
1455static void WriteFunction(const Function &F, llvm_3_2::ValueEnumerator &VE,
1456                          BitstreamWriter &Stream) {
1457  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1458  VE.incorporateFunction(F);
1459
1460  SmallVector<unsigned, 64> Vals;
1461
1462  // Emit the number of basic blocks, so the reader can create them ahead of
1463  // time.
1464  Vals.push_back(VE.getBasicBlocks().size());
1465  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1466  Vals.clear();
1467
1468  // If there are function-local constants, emit them now.
1469  unsigned CstStart, CstEnd;
1470  VE.getFunctionConstantRange(CstStart, CstEnd);
1471  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1472
1473  // If there is function-local metadata, emit it now.
1474  WriteFunctionLocalMetadata(F, VE, Stream);
1475
1476  // Keep a running idea of what the instruction ID is.
1477  unsigned InstID = CstEnd;
1478
1479  bool NeedsMetadataAttachment = false;
1480
1481  DebugLoc LastDL;
1482
1483  // Finally, emit all the instructions, in order.
1484  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1485    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1486         I != E; ++I) {
1487      WriteInstruction(*I, InstID, VE, Stream, Vals);
1488
1489      if (!I->getType()->isVoidTy())
1490        ++InstID;
1491
1492      // If the instruction has metadata, write a metadata attachment later.
1493      NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1494
1495      // If the instruction has a debug location, emit it.
1496      DebugLoc DL = I->getDebugLoc();
1497      if (DL.isUnknown()) {
1498        // nothing todo.
1499      } else if (DL == LastDL) {
1500        // Just repeat the same debug loc as last time.
1501        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1502      } else {
1503        MDNode *Scope, *IA;
1504        DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1505
1506        Vals.push_back(DL.getLine());
1507        Vals.push_back(DL.getCol());
1508        Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1509        Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1510        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1511        Vals.clear();
1512
1513        LastDL = DL;
1514      }
1515    }
1516
1517  // Emit names for all the instructions etc.
1518  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1519
1520  if (NeedsMetadataAttachment)
1521    WriteMetadataAttachment(F, VE, Stream);
1522  VE.purgeFunction();
1523  Stream.ExitBlock();
1524}
1525
1526// Emit blockinfo, which defines the standard abbreviations etc.
1527static void WriteBlockInfo(const llvm_3_2::ValueEnumerator &VE,
1528                           BitstreamWriter &Stream) {
1529  // We only want to emit block info records for blocks that have multiple
1530  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1531  // blocks can defined their abbrevs inline.
1532  Stream.EnterBlockInfoBlock(2);
1533
1534  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1535    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1536    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1537    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1538    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1539    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1540    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1541                                   Abbv) != VST_ENTRY_8_ABBREV)
1542      llvm_unreachable("Unexpected abbrev ordering!");
1543  }
1544
1545  { // 7-bit fixed width VST_ENTRY strings.
1546    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1547    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1548    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1549    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1550    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1551    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1552                                   Abbv) != VST_ENTRY_7_ABBREV)
1553      llvm_unreachable("Unexpected abbrev ordering!");
1554  }
1555  { // 6-bit char6 VST_ENTRY strings.
1556    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1557    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1558    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1559    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1560    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1561    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1562                                   Abbv) != VST_ENTRY_6_ABBREV)
1563      llvm_unreachable("Unexpected abbrev ordering!");
1564  }
1565  { // 6-bit char6 VST_BBENTRY strings.
1566    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1567    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1568    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1569    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1570    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1571    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1572                                   Abbv) != VST_BBENTRY_6_ABBREV)
1573      llvm_unreachable("Unexpected abbrev ordering!");
1574  }
1575
1576
1577
1578  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1579    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1580    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1581    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1582                              Log2_32_Ceil(VE.getTypes().size()+1)));
1583    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1584                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1585      llvm_unreachable("Unexpected abbrev ordering!");
1586  }
1587
1588  { // INTEGER abbrev for CONSTANTS_BLOCK.
1589    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1590    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1591    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1592    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1593                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1594      llvm_unreachable("Unexpected abbrev ordering!");
1595  }
1596
1597  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1598    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1599    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1600    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1601    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1602                              Log2_32_Ceil(VE.getTypes().size()+1)));
1603    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1604
1605    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1606                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1607      llvm_unreachable("Unexpected abbrev ordering!");
1608  }
1609  { // NULL abbrev for CONSTANTS_BLOCK.
1610    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1611    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1612    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1613                                   Abbv) != CONSTANTS_NULL_Abbrev)
1614      llvm_unreachable("Unexpected abbrev ordering!");
1615  }
1616
1617  // FIXME: This should only use space for first class types!
1618
1619  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1620    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1621    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1622    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1623    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1624    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1625    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1626                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1627      llvm_unreachable("Unexpected abbrev ordering!");
1628  }
1629  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1630    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1631    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1632    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1633    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1634    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1635    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1636                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1637      llvm_unreachable("Unexpected abbrev ordering!");
1638  }
1639  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1640    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1641    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1642    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1643    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1644    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1645    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1646    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1647                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1648      llvm_unreachable("Unexpected abbrev ordering!");
1649  }
1650  { // INST_CAST abbrev for FUNCTION_BLOCK.
1651    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1652    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1653    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1654    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1655                              Log2_32_Ceil(VE.getTypes().size()+1)));
1656    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1657    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1658                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1659      llvm_unreachable("Unexpected abbrev ordering!");
1660  }
1661
1662  { // INST_RET abbrev for FUNCTION_BLOCK.
1663    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1664    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1665    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1666                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1667      llvm_unreachable("Unexpected abbrev ordering!");
1668  }
1669  { // INST_RET abbrev for FUNCTION_BLOCK.
1670    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1671    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1672    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1673    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1674                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1675      llvm_unreachable("Unexpected abbrev ordering!");
1676  }
1677  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1678    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1679    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1680    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1681                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1682      llvm_unreachable("Unexpected abbrev ordering!");
1683  }
1684
1685  Stream.ExitBlock();
1686}
1687
1688// Sort the Users based on the order in which the reader parses the bitcode
1689// file.
1690static bool bitcodereader_order(const User *lhs, const User *rhs) {
1691  // TODO: Implement.
1692  return true;
1693}
1694
1695static void WriteUseList(const Value *V, const llvm_3_2::ValueEnumerator &VE,
1696                         BitstreamWriter &Stream) {
1697
1698  // One or zero uses can't get out of order.
1699  if (V->use_empty() || V->hasNUses(1))
1700    return;
1701
1702  // Make a copy of the in-memory use-list for sorting.
1703  unsigned UseListSize = std::distance(V->use_begin(), V->use_end());
1704  SmallVector<const User*, 8> UseList;
1705  UseList.reserve(UseListSize);
1706  for (Value::const_use_iterator I = V->use_begin(), E = V->use_end();
1707       I != E; ++I) {
1708    const User *U = *I;
1709    UseList.push_back(U);
1710  }
1711
1712  // Sort the copy based on the order read by the BitcodeReader.
1713  std::sort(UseList.begin(), UseList.end(), bitcodereader_order);
1714
1715  // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1716  // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1717
1718  // TODO: Emit the USELIST_CODE_ENTRYs.
1719}
1720
1721static void WriteFunctionUseList(const Function *F,
1722                                 llvm_3_2::ValueEnumerator &VE,
1723                                 BitstreamWriter &Stream) {
1724  VE.incorporateFunction(*F);
1725
1726  for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1727       AI != AE; ++AI)
1728    WriteUseList(AI, VE, Stream);
1729  for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1730       ++BB) {
1731    WriteUseList(BB, VE, Stream);
1732    for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1733         ++II) {
1734      WriteUseList(II, VE, Stream);
1735      for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1736           OI != E; ++OI) {
1737        if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1738            isa<InlineAsm>(*OI))
1739          WriteUseList(*OI, VE, Stream);
1740      }
1741    }
1742  }
1743  VE.purgeFunction();
1744}
1745
1746// Emit use-lists.
1747static void WriteModuleUseLists(const Module *M, llvm_3_2::ValueEnumerator &VE,
1748                                BitstreamWriter &Stream) {
1749  Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1750
1751  // XXX: this modifies the module, but in a way that should never change the
1752  // behavior of any pass or codegen in LLVM. The problem is that GVs may
1753  // contain entries in the use_list that do not exist in the Module and are
1754  // not stored in the .bc file.
1755  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1756       I != E; ++I)
1757    I->removeDeadConstantUsers();
1758
1759  // Write the global variables.
1760  for (Module::const_global_iterator GI = M->global_begin(),
1761         GE = M->global_end(); GI != GE; ++GI) {
1762    WriteUseList(GI, VE, Stream);
1763
1764    // Write the global variable initializers.
1765    if (GI->hasInitializer())
1766      WriteUseList(GI->getInitializer(), VE, Stream);
1767  }
1768
1769  // Write the functions.
1770  for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1771    WriteUseList(FI, VE, Stream);
1772    if (!FI->isDeclaration())
1773      WriteFunctionUseList(FI, VE, Stream);
1774  }
1775
1776  // Write the aliases.
1777  for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1778       AI != AE; ++AI) {
1779    WriteUseList(AI, VE, Stream);
1780    WriteUseList(AI->getAliasee(), VE, Stream);
1781  }
1782
1783  Stream.ExitBlock();
1784}
1785
1786/// WriteModule - Emit the specified module to the bitstream.
1787static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1788  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1789
1790  // Emit the version number if it is non-zero.
1791  if (CurVersion) {
1792    SmallVector<unsigned, 1> Vals;
1793    Vals.push_back(CurVersion);
1794    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1795  }
1796
1797  // Analyze the module, enumerating globals, functions, etc.
1798  llvm_3_2::ValueEnumerator VE(M);
1799
1800  // Emit blockinfo, which defines the standard abbreviations etc.
1801  WriteBlockInfo(VE, Stream);
1802
1803  // Emit information about parameter attributes.
1804  WriteAttributeTable(VE, Stream);
1805
1806  // Emit information describing all of the types in the module.
1807  WriteTypeTable(VE, Stream);
1808
1809  // Emit top-level description of module, including target triple, inline asm,
1810  // descriptors for global variables, and function prototype info.
1811  WriteModuleInfo(M, VE, Stream);
1812
1813  // Emit constants.
1814  WriteModuleConstants(VE, Stream);
1815
1816  // Emit metadata.
1817  WriteModuleMetadata(M, VE, Stream);
1818
1819  // Emit metadata.
1820  WriteModuleMetadataStore(M, Stream);
1821
1822  // Emit names for globals/functions etc.
1823  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1824
1825  // Emit use-lists.
1826  if (EnablePreserveUseListOrdering)
1827    WriteModuleUseLists(M, VE, Stream);
1828
1829  // Emit function bodies.
1830  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1831    if (!F->isDeclaration())
1832      WriteFunction(*F, VE, Stream);
1833
1834  Stream.ExitBlock();
1835}
1836
1837/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1838/// header and trailer to make it compatible with the system archiver.  To do
1839/// this we emit the following header, and then emit a trailer that pads the
1840/// file out to be a multiple of 16 bytes.
1841///
1842/// struct bc_header {
1843///   uint32_t Magic;         // 0x0B17C0DE
1844///   uint32_t Version;       // Version, currently always 0.
1845///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1846///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1847///   uint32_t CPUType;       // CPU specifier.
1848///   ... potentially more later ...
1849/// };
1850enum {
1851  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1852  DarwinBCHeaderSize = 5*4
1853};
1854
1855static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1856                               uint32_t &Position) {
1857  Buffer[Position + 0] = (unsigned char) (Value >>  0);
1858  Buffer[Position + 1] = (unsigned char) (Value >>  8);
1859  Buffer[Position + 2] = (unsigned char) (Value >> 16);
1860  Buffer[Position + 3] = (unsigned char) (Value >> 24);
1861  Position += 4;
1862}
1863
1864static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1865                                         const Triple &TT) {
1866  unsigned CPUType = ~0U;
1867
1868  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1869  // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1870  // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1871  // specific constants here because they are implicitly part of the Darwin ABI.
1872  enum {
1873    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1874    DARWIN_CPU_TYPE_X86        = 7,
1875    DARWIN_CPU_TYPE_ARM        = 12,
1876    DARWIN_CPU_TYPE_POWERPC    = 18
1877  };
1878
1879  Triple::ArchType Arch = TT.getArch();
1880  if (Arch == Triple::x86_64)
1881    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1882  else if (Arch == Triple::x86)
1883    CPUType = DARWIN_CPU_TYPE_X86;
1884  else if (Arch == Triple::ppc)
1885    CPUType = DARWIN_CPU_TYPE_POWERPC;
1886  else if (Arch == Triple::ppc64)
1887    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1888  else if (Arch == Triple::arm || Arch == Triple::thumb)
1889    CPUType = DARWIN_CPU_TYPE_ARM;
1890
1891  // Traditional Bitcode starts after header.
1892  assert(Buffer.size() >= DarwinBCHeaderSize &&
1893         "Expected header size to be reserved");
1894  unsigned BCOffset = DarwinBCHeaderSize;
1895  unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
1896
1897  // Write the magic and version.
1898  unsigned Position = 0;
1899  WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
1900  WriteInt32ToBuffer(0          , Buffer, Position); // Version.
1901  WriteInt32ToBuffer(BCOffset   , Buffer, Position);
1902  WriteInt32ToBuffer(BCSize     , Buffer, Position);
1903  WriteInt32ToBuffer(CPUType    , Buffer, Position);
1904
1905  // If the file is not a multiple of 16 bytes, insert dummy padding.
1906  while (Buffer.size() & 15)
1907    Buffer.push_back(0);
1908}
1909
1910/// WriteBitcodeToFile - Write the specified module to the specified output
1911/// stream.
1912void llvm_3_2::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1913  SmallVector<char, 1024> Buffer;
1914  Buffer.reserve(256*1024);
1915
1916  // If this is darwin or another generic macho target, reserve space for the
1917  // header.
1918  Triple TT(M->getTargetTriple());
1919  if (TT.isOSDarwin())
1920    Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
1921
1922  // Emit the module into the buffer.
1923  {
1924    BitstreamWriter Stream(Buffer);
1925
1926    // Emit the file header.
1927    Stream.Emit((unsigned)'B', 8);
1928    Stream.Emit((unsigned)'C', 8);
1929    Stream.Emit(0x0, 4);
1930    Stream.Emit(0xC, 4);
1931    Stream.Emit(0xE, 4);
1932    Stream.Emit(0xD, 4);
1933
1934    // Emit the module.
1935    WriteModule(M, Stream);
1936  }
1937
1938  if (TT.isOSDarwin())
1939    EmitDarwinBCHeaderAndTrailer(Buffer, TT);
1940
1941  // Write the generated bitstream to "Out".
1942  Out.write((char*)&Buffer.front(), Buffer.size());
1943}
1944