BitcodeWriter.cpp revision 1d0be15f89cb5056e20e2d24faa8d6afb1573bca 
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/Metadata.h"
23#include "llvm/Module.h"
24#include "llvm/Operator.h"
25#include "llvm/TypeSymbolTable.h"
26#include "llvm/ValueSymbolTable.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/MathExtras.h"
29#include "llvm/Support/Streams.h"
30#include "llvm/Support/raw_ostream.h"
31#include "llvm/System/Program.h"
32using namespace llvm;
33
34/// These are manifest constants used by the bitcode writer. They do not need to
35/// be kept in sync with the reader, but need to be consistent within this file.
36enum {
37  CurVersion = 0,
38
39  // VALUE_SYMTAB_BLOCK abbrev id's.
40  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
41  VST_ENTRY_7_ABBREV,
42  VST_ENTRY_6_ABBREV,
43  VST_BBENTRY_6_ABBREV,
44
45  // CONSTANTS_BLOCK abbrev id's.
46  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
47  CONSTANTS_INTEGER_ABBREV,
48  CONSTANTS_CE_CAST_Abbrev,
49  CONSTANTS_NULL_Abbrev,
50
51  // FUNCTION_BLOCK abbrev id's.
52  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
53  FUNCTION_INST_BINOP_ABBREV,
54  FUNCTION_INST_BINOP_FLAGS_ABBREV,
55  FUNCTION_INST_CAST_ABBREV,
56  FUNCTION_INST_RET_VOID_ABBREV,
57  FUNCTION_INST_RET_VAL_ABBREV,
58  FUNCTION_INST_UNREACHABLE_ABBREV
59};
60
61
62static unsigned GetEncodedCastOpcode(unsigned Opcode) {
63  switch (Opcode) {
64  default: llvm_unreachable("Unknown cast instruction!");
65  case Instruction::Trunc   : return bitc::CAST_TRUNC;
66  case Instruction::ZExt    : return bitc::CAST_ZEXT;
67  case Instruction::SExt    : return bitc::CAST_SEXT;
68  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
69  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
70  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
71  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
72  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
73  case Instruction::FPExt   : return bitc::CAST_FPEXT;
74  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
75  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
76  case Instruction::BitCast : return bitc::CAST_BITCAST;
77  }
78}
79
80static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
81  switch (Opcode) {
82  default: llvm_unreachable("Unknown binary instruction!");
83  case Instruction::Add:
84  case Instruction::FAdd: return bitc::BINOP_ADD;
85  case Instruction::Sub:
86  case Instruction::FSub: return bitc::BINOP_SUB;
87  case Instruction::Mul:
88  case Instruction::FMul: return bitc::BINOP_MUL;
89  case Instruction::UDiv: return bitc::BINOP_UDIV;
90  case Instruction::FDiv:
91  case Instruction::SDiv: return bitc::BINOP_SDIV;
92  case Instruction::URem: return bitc::BINOP_UREM;
93  case Instruction::FRem:
94  case Instruction::SRem: return bitc::BINOP_SREM;
95  case Instruction::Shl:  return bitc::BINOP_SHL;
96  case Instruction::LShr: return bitc::BINOP_LSHR;
97  case Instruction::AShr: return bitc::BINOP_ASHR;
98  case Instruction::And:  return bitc::BINOP_AND;
99  case Instruction::Or:   return bitc::BINOP_OR;
100  case Instruction::Xor:  return bitc::BINOP_XOR;
101  }
102}
103
104
105
106static void WriteStringRecord(unsigned Code, const std::string &Str,
107                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
108  SmallVector<unsigned, 64> Vals;
109
110  // Code: [strchar x N]
111  for (unsigned i = 0, e = Str.size(); i != e; ++i)
112    Vals.push_back(Str[i]);
113
114  // Emit the finished record.
115  Stream.EmitRecord(Code, Vals, AbbrevToUse);
116}
117
118// Emit information about parameter attributes.
119static void WriteAttributeTable(const ValueEnumerator &VE,
120                                BitstreamWriter &Stream) {
121  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
122  if (Attrs.empty()) return;
123
124  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
125
126  SmallVector<uint64_t, 64> Record;
127  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
128    const AttrListPtr &A = Attrs[i];
129    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
130      const AttributeWithIndex &PAWI = A.getSlot(i);
131      Record.push_back(PAWI.Index);
132
133      // FIXME: remove in LLVM 3.0
134      // Store the alignment in the bitcode as a 16-bit raw value instead of a
135      // 5-bit log2 encoded value. Shift the bits above the alignment up by
136      // 11 bits.
137      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
138      if (PAWI.Attrs & Attribute::Alignment)
139        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
140      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
141
142      Record.push_back(FauxAttr);
143    }
144
145    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
146    Record.clear();
147  }
148
149  Stream.ExitBlock();
150}
151
152/// WriteTypeTable - Write out the type table for a module.
153static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
154  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
155
156  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
157  SmallVector<uint64_t, 64> TypeVals;
158
159  // Abbrev for TYPE_CODE_POINTER.
160  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
161  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
162  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
163                            Log2_32_Ceil(VE.getTypes().size()+1)));
164  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
165  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
166
167  // Abbrev for TYPE_CODE_FUNCTION.
168  Abbv = new BitCodeAbbrev();
169  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
171  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
172  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
173  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
174                            Log2_32_Ceil(VE.getTypes().size()+1)));
175  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
176
177  // Abbrev for TYPE_CODE_STRUCT.
178  Abbv = new BitCodeAbbrev();
179  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
181  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
182  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
183                            Log2_32_Ceil(VE.getTypes().size()+1)));
184  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
185
186  // Abbrev for TYPE_CODE_ARRAY.
187  Abbv = new BitCodeAbbrev();
188  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
189  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
190  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
191                            Log2_32_Ceil(VE.getTypes().size()+1)));
192  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
193
194  // Emit an entry count so the reader can reserve space.
195  TypeVals.push_back(TypeList.size());
196  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
197  TypeVals.clear();
198
199  // Loop over all of the types, emitting each in turn.
200  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
201    const Type *T = TypeList[i].first;
202    int AbbrevToUse = 0;
203    unsigned Code = 0;
204
205    switch (T->getTypeID()) {
206    default: llvm_unreachable("Unknown type!");
207    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
208    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
209    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
210    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
211    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
212    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
213    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
214    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
215    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
216    case Type::IntegerTyID:
217      // INTEGER: [width]
218      Code = bitc::TYPE_CODE_INTEGER;
219      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
220      break;
221    case Type::PointerTyID: {
222      const PointerType *PTy = cast<PointerType>(T);
223      // POINTER: [pointee type, address space]
224      Code = bitc::TYPE_CODE_POINTER;
225      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
226      unsigned AddressSpace = PTy->getAddressSpace();
227      TypeVals.push_back(AddressSpace);
228      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
229      break;
230    }
231    case Type::FunctionTyID: {
232      const FunctionType *FT = cast<FunctionType>(T);
233      // FUNCTION: [isvararg, attrid, retty, paramty x N]
234      Code = bitc::TYPE_CODE_FUNCTION;
235      TypeVals.push_back(FT->isVarArg());
236      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
237      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
238      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
239        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
240      AbbrevToUse = FunctionAbbrev;
241      break;
242    }
243    case Type::StructTyID: {
244      const StructType *ST = cast<StructType>(T);
245      // STRUCT: [ispacked, eltty x N]
246      Code = bitc::TYPE_CODE_STRUCT;
247      TypeVals.push_back(ST->isPacked());
248      // Output all of the element types.
249      for (StructType::element_iterator I = ST->element_begin(),
250           E = ST->element_end(); I != E; ++I)
251        TypeVals.push_back(VE.getTypeID(*I));
252      AbbrevToUse = StructAbbrev;
253      break;
254    }
255    case Type::ArrayTyID: {
256      const ArrayType *AT = cast<ArrayType>(T);
257      // ARRAY: [numelts, eltty]
258      Code = bitc::TYPE_CODE_ARRAY;
259      TypeVals.push_back(AT->getNumElements());
260      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
261      AbbrevToUse = ArrayAbbrev;
262      break;
263    }
264    case Type::VectorTyID: {
265      const VectorType *VT = cast<VectorType>(T);
266      // VECTOR [numelts, eltty]
267      Code = bitc::TYPE_CODE_VECTOR;
268      TypeVals.push_back(VT->getNumElements());
269      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
270      break;
271    }
272    }
273
274    // Emit the finished record.
275    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
276    TypeVals.clear();
277  }
278
279  Stream.ExitBlock();
280}
281
282static unsigned getEncodedLinkage(const GlobalValue *GV) {
283  switch (GV->getLinkage()) {
284  default: llvm_unreachable("Invalid linkage!");
285  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
286  case GlobalValue::ExternalLinkage:            return 0;
287  case GlobalValue::WeakAnyLinkage:             return 1;
288  case GlobalValue::AppendingLinkage:           return 2;
289  case GlobalValue::InternalLinkage:            return 3;
290  case GlobalValue::LinkOnceAnyLinkage:         return 4;
291  case GlobalValue::DLLImportLinkage:           return 5;
292  case GlobalValue::DLLExportLinkage:           return 6;
293  case GlobalValue::ExternalWeakLinkage:        return 7;
294  case GlobalValue::CommonLinkage:              return 8;
295  case GlobalValue::PrivateLinkage:             return 9;
296  case GlobalValue::WeakODRLinkage:             return 10;
297  case GlobalValue::LinkOnceODRLinkage:         return 11;
298  case GlobalValue::AvailableExternallyLinkage: return 12;
299  case GlobalValue::LinkerPrivateLinkage:       return 13;
300  }
301}
302
303static unsigned getEncodedVisibility(const GlobalValue *GV) {
304  switch (GV->getVisibility()) {
305  default: llvm_unreachable("Invalid visibility!");
306  case GlobalValue::DefaultVisibility:   return 0;
307  case GlobalValue::HiddenVisibility:    return 1;
308  case GlobalValue::ProtectedVisibility: return 2;
309  }
310}
311
312// Emit top-level description of module, including target triple, inline asm,
313// descriptors for global variables, and function prototype info.
314static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
315                            BitstreamWriter &Stream) {
316  // Emit the list of dependent libraries for the Module.
317  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
318    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
319
320  // Emit various pieces of data attached to a module.
321  if (!M->getTargetTriple().empty())
322    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
323                      0/*TODO*/, Stream);
324  if (!M->getDataLayout().empty())
325    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
326                      0/*TODO*/, Stream);
327  if (!M->getModuleInlineAsm().empty())
328    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
329                      0/*TODO*/, Stream);
330
331  // Emit information about sections and GC, computing how many there are. Also
332  // compute the maximum alignment value.
333  std::map<std::string, unsigned> SectionMap;
334  std::map<std::string, unsigned> GCMap;
335  unsigned MaxAlignment = 0;
336  unsigned MaxGlobalType = 0;
337  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
338       GV != E; ++GV) {
339    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
340    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
341
342    if (!GV->hasSection()) continue;
343    // Give section names unique ID's.
344    unsigned &Entry = SectionMap[GV->getSection()];
345    if (Entry != 0) continue;
346    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
347                      0/*TODO*/, Stream);
348    Entry = SectionMap.size();
349  }
350  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
351    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
352    if (F->hasSection()) {
353      // Give section names unique ID's.
354      unsigned &Entry = SectionMap[F->getSection()];
355      if (!Entry) {
356        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
357                          0/*TODO*/, Stream);
358        Entry = SectionMap.size();
359      }
360    }
361    if (F->hasGC()) {
362      // Same for GC names.
363      unsigned &Entry = GCMap[F->getGC()];
364      if (!Entry) {
365        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
366                          0/*TODO*/, Stream);
367        Entry = GCMap.size();
368      }
369    }
370  }
371
372  // Emit abbrev for globals, now that we know # sections and max alignment.
373  unsigned SimpleGVarAbbrev = 0;
374  if (!M->global_empty()) {
375    // Add an abbrev for common globals with no visibility or thread localness.
376    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
377    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
379                              Log2_32_Ceil(MaxGlobalType+1)));
380    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
381    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
382    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
383    if (MaxAlignment == 0)                                      // Alignment.
384      Abbv->Add(BitCodeAbbrevOp(0));
385    else {
386      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
387      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
388                               Log2_32_Ceil(MaxEncAlignment+1)));
389    }
390    if (SectionMap.empty())                                    // Section.
391      Abbv->Add(BitCodeAbbrevOp(0));
392    else
393      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
394                               Log2_32_Ceil(SectionMap.size()+1)));
395    // Don't bother emitting vis + thread local.
396    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
397  }
398
399  // Emit the global variable information.
400  SmallVector<unsigned, 64> Vals;
401  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
402       GV != E; ++GV) {
403    unsigned AbbrevToUse = 0;
404
405    // GLOBALVAR: [type, isconst, initid,
406    //             linkage, alignment, section, visibility, threadlocal]
407    Vals.push_back(VE.getTypeID(GV->getType()));
408    Vals.push_back(GV->isConstant());
409    Vals.push_back(GV->isDeclaration() ? 0 :
410                   (VE.getValueID(GV->getInitializer()) + 1));
411    Vals.push_back(getEncodedLinkage(GV));
412    Vals.push_back(Log2_32(GV->getAlignment())+1);
413    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
414    if (GV->isThreadLocal() ||
415        GV->getVisibility() != GlobalValue::DefaultVisibility) {
416      Vals.push_back(getEncodedVisibility(GV));
417      Vals.push_back(GV->isThreadLocal());
418    } else {
419      AbbrevToUse = SimpleGVarAbbrev;
420    }
421
422    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
423    Vals.clear();
424  }
425
426  // Emit the function proto information.
427  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
428    // FUNCTION:  [type, callingconv, isproto, paramattr,
429    //             linkage, alignment, section, visibility, gc]
430    Vals.push_back(VE.getTypeID(F->getType()));
431    Vals.push_back(F->getCallingConv());
432    Vals.push_back(F->isDeclaration());
433    Vals.push_back(getEncodedLinkage(F));
434    Vals.push_back(VE.getAttributeID(F->getAttributes()));
435    Vals.push_back(Log2_32(F->getAlignment())+1);
436    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
437    Vals.push_back(getEncodedVisibility(F));
438    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
439
440    unsigned AbbrevToUse = 0;
441    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
442    Vals.clear();
443  }
444
445
446  // Emit the alias information.
447  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
448       AI != E; ++AI) {
449    Vals.push_back(VE.getTypeID(AI->getType()));
450    Vals.push_back(VE.getValueID(AI->getAliasee()));
451    Vals.push_back(getEncodedLinkage(AI));
452    Vals.push_back(getEncodedVisibility(AI));
453    unsigned AbbrevToUse = 0;
454    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
455    Vals.clear();
456  }
457}
458
459static uint64_t GetOptimizationFlags(const Value *V) {
460  uint64_t Flags = 0;
461
462  if (const OverflowingBinaryOperator *OBO =
463        dyn_cast<OverflowingBinaryOperator>(V)) {
464    if (OBO->hasNoSignedOverflow())
465      Flags |= 1 << bitc::OBO_NO_SIGNED_OVERFLOW;
466    if (OBO->hasNoUnsignedOverflow())
467      Flags |= 1 << bitc::OBO_NO_UNSIGNED_OVERFLOW;
468  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
469    if (Div->isExact())
470      Flags |= 1 << bitc::SDIV_EXACT;
471  }
472
473  return Flags;
474}
475
476static void WriteMDNode(const MDNode *N,
477                        const ValueEnumerator &VE,
478                        BitstreamWriter &Stream,
479                        SmallVector<uint64_t, 64> &Record) {
480  for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
481    if (N->getElement(i)) {
482      Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
483      Record.push_back(VE.getValueID(N->getElement(i)));
484    } else {
485      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
486      Record.push_back(0);
487    }
488  }
489  Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
490  Record.clear();
491}
492
493static void WriteModuleMetadata(const ValueEnumerator &VE,
494                                BitstreamWriter &Stream) {
495  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
496  bool StartedMetadataBlock = false;
497  unsigned MDSAbbrev = 0;
498  SmallVector<uint64_t, 64> Record;
499  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
500
501    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
502      if (!StartedMetadataBlock) {
503        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
504        StartedMetadataBlock = true;
505      }
506      WriteMDNode(N, VE, Stream, Record);
507    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
508      if (!StartedMetadataBlock)  {
509        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
510
511        // Abbrev for METADATA_STRING.
512        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
513        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
514        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
515        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
516        MDSAbbrev = Stream.EmitAbbrev(Abbv);
517        StartedMetadataBlock = true;
518      }
519
520      // Code: [strchar x N]
521      const char *StrBegin = MDS->begin();
522      for (unsigned i = 0, e = MDS->length(); i != e; ++i)
523        Record.push_back(StrBegin[i]);
524
525      // Emit the finished record.
526      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
527      Record.clear();
528    } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
529      if (!StartedMetadataBlock)  {
530        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
531        StartedMetadataBlock = true;
532      }
533
534      // Write name.
535      std::string Str = NMD->getNameStr();
536      const char *StrBegin = Str.c_str();
537      for (unsigned i = 0, e = Str.length(); i != e; ++i)
538        Record.push_back(StrBegin[i]);
539      Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
540      Record.clear();
541
542      // Write named metadata elements.
543      for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
544        if (NMD->getElement(i))
545          Record.push_back(VE.getValueID(NMD->getElement(i)));
546        else
547          Record.push_back(0);
548      }
549      Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
550      Record.clear();
551    }
552  }
553
554  if (StartedMetadataBlock)
555    Stream.ExitBlock();
556}
557
558static void WriteConstants(unsigned FirstVal, unsigned LastVal,
559                           const ValueEnumerator &VE,
560                           BitstreamWriter &Stream, bool isGlobal) {
561  if (FirstVal == LastVal) return;
562
563  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
564
565  unsigned AggregateAbbrev = 0;
566  unsigned String8Abbrev = 0;
567  unsigned CString7Abbrev = 0;
568  unsigned CString6Abbrev = 0;
569  // If this is a constant pool for the module, emit module-specific abbrevs.
570  if (isGlobal) {
571    // Abbrev for CST_CODE_AGGREGATE.
572    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
573    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
574    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
575    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
576    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
577
578    // Abbrev for CST_CODE_STRING.
579    Abbv = new BitCodeAbbrev();
580    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
581    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
582    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
583    String8Abbrev = Stream.EmitAbbrev(Abbv);
584    // Abbrev for CST_CODE_CSTRING.
585    Abbv = new BitCodeAbbrev();
586    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
587    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
588    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
589    CString7Abbrev = Stream.EmitAbbrev(Abbv);
590    // Abbrev for CST_CODE_CSTRING.
591    Abbv = new BitCodeAbbrev();
592    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
593    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
594    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
595    CString6Abbrev = Stream.EmitAbbrev(Abbv);
596  }
597
598  SmallVector<uint64_t, 64> Record;
599
600  const ValueEnumerator::ValueList &Vals = VE.getValues();
601  const Type *LastTy = 0;
602  for (unsigned i = FirstVal; i != LastVal; ++i) {
603    const Value *V = Vals[i].first;
604    // If we need to switch types, do so now.
605    if (V->getType() != LastTy) {
606      LastTy = V->getType();
607      Record.push_back(VE.getTypeID(LastTy));
608      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
609                        CONSTANTS_SETTYPE_ABBREV);
610      Record.clear();
611    }
612
613    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
614      Record.push_back(unsigned(IA->hasSideEffects()));
615
616      // Add the asm string.
617      const std::string &AsmStr = IA->getAsmString();
618      Record.push_back(AsmStr.size());
619      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
620        Record.push_back(AsmStr[i]);
621
622      // Add the constraint string.
623      const std::string &ConstraintStr = IA->getConstraintString();
624      Record.push_back(ConstraintStr.size());
625      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
626        Record.push_back(ConstraintStr[i]);
627      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
628      Record.clear();
629      continue;
630    }
631    const Constant *C = cast<Constant>(V);
632    unsigned Code = -1U;
633    unsigned AbbrevToUse = 0;
634    if (C->isNullValue()) {
635      Code = bitc::CST_CODE_NULL;
636    } else if (isa<UndefValue>(C)) {
637      Code = bitc::CST_CODE_UNDEF;
638    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
639      if (IV->getBitWidth() <= 64) {
640        int64_t V = IV->getSExtValue();
641        if (V >= 0)
642          Record.push_back(V << 1);
643        else
644          Record.push_back((-V << 1) | 1);
645        Code = bitc::CST_CODE_INTEGER;
646        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
647      } else {                             // Wide integers, > 64 bits in size.
648        // We have an arbitrary precision integer value to write whose
649        // bit width is > 64. However, in canonical unsigned integer
650        // format it is likely that the high bits are going to be zero.
651        // So, we only write the number of active words.
652        unsigned NWords = IV->getValue().getActiveWords();
653        const uint64_t *RawWords = IV->getValue().getRawData();
654        for (unsigned i = 0; i != NWords; ++i) {
655          int64_t V = RawWords[i];
656          if (V >= 0)
657            Record.push_back(V << 1);
658          else
659            Record.push_back((-V << 1) | 1);
660        }
661        Code = bitc::CST_CODE_WIDE_INTEGER;
662      }
663    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
664      Code = bitc::CST_CODE_FLOAT;
665      const Type *Ty = CFP->getType();
666      if (Ty == Type::getFloatTy(Ty->getContext()) ||
667          Ty == Type::getDoubleTy(Ty->getContext())) {
668        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
669      } else if (Ty == Type::getX86_FP80Ty(Ty->getContext())) {
670        // api needed to prevent premature destruction
671        // bits are not in the same order as a normal i80 APInt, compensate.
672        APInt api = CFP->getValueAPF().bitcastToAPInt();
673        const uint64_t *p = api.getRawData();
674        Record.push_back((p[1] << 48) | (p[0] >> 16));
675        Record.push_back(p[0] & 0xffffLL);
676      } else if (Ty == Type::getFP128Ty(Ty->getContext()) ||
677                 Ty == Type::getPPC_FP128Ty(Ty->getContext())) {
678        APInt api = CFP->getValueAPF().bitcastToAPInt();
679        const uint64_t *p = api.getRawData();
680        Record.push_back(p[0]);
681        Record.push_back(p[1]);
682      } else {
683        assert (0 && "Unknown FP type!");
684      }
685    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
686      // Emit constant strings specially.
687      unsigned NumOps = C->getNumOperands();
688      // If this is a null-terminated string, use the denser CSTRING encoding.
689      if (C->getOperand(NumOps-1)->isNullValue()) {
690        Code = bitc::CST_CODE_CSTRING;
691        --NumOps;  // Don't encode the null, which isn't allowed by char6.
692      } else {
693        Code = bitc::CST_CODE_STRING;
694        AbbrevToUse = String8Abbrev;
695      }
696      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
697      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
698      for (unsigned i = 0; i != NumOps; ++i) {
699        unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
700        Record.push_back(V);
701        isCStr7 &= (V & 128) == 0;
702        if (isCStrChar6)
703          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
704      }
705
706      if (isCStrChar6)
707        AbbrevToUse = CString6Abbrev;
708      else if (isCStr7)
709        AbbrevToUse = CString7Abbrev;
710    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
711               isa<ConstantVector>(V)) {
712      Code = bitc::CST_CODE_AGGREGATE;
713      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
714        Record.push_back(VE.getValueID(C->getOperand(i)));
715      AbbrevToUse = AggregateAbbrev;
716    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
717      switch (CE->getOpcode()) {
718      default:
719        if (Instruction::isCast(CE->getOpcode())) {
720          Code = bitc::CST_CODE_CE_CAST;
721          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
722          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
723          Record.push_back(VE.getValueID(C->getOperand(0)));
724          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
725        } else {
726          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
727          Code = bitc::CST_CODE_CE_BINOP;
728          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
729          Record.push_back(VE.getValueID(C->getOperand(0)));
730          Record.push_back(VE.getValueID(C->getOperand(1)));
731          uint64_t Flags = GetOptimizationFlags(CE);
732          if (Flags != 0)
733            Record.push_back(Flags);
734        }
735        break;
736      case Instruction::GetElementPtr:
737        Code = bitc::CST_CODE_CE_GEP;
738        if (cast<GEPOperator>(C)->isInBounds())
739          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
740        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
741          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
742          Record.push_back(VE.getValueID(C->getOperand(i)));
743        }
744        break;
745      case Instruction::Select:
746        Code = bitc::CST_CODE_CE_SELECT;
747        Record.push_back(VE.getValueID(C->getOperand(0)));
748        Record.push_back(VE.getValueID(C->getOperand(1)));
749        Record.push_back(VE.getValueID(C->getOperand(2)));
750        break;
751      case Instruction::ExtractElement:
752        Code = bitc::CST_CODE_CE_EXTRACTELT;
753        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
754        Record.push_back(VE.getValueID(C->getOperand(0)));
755        Record.push_back(VE.getValueID(C->getOperand(1)));
756        break;
757      case Instruction::InsertElement:
758        Code = bitc::CST_CODE_CE_INSERTELT;
759        Record.push_back(VE.getValueID(C->getOperand(0)));
760        Record.push_back(VE.getValueID(C->getOperand(1)));
761        Record.push_back(VE.getValueID(C->getOperand(2)));
762        break;
763      case Instruction::ShuffleVector:
764        // If the return type and argument types are the same, this is a
765        // standard shufflevector instruction.  If the types are different,
766        // then the shuffle is widening or truncating the input vectors, and
767        // the argument type must also be encoded.
768        if (C->getType() == C->getOperand(0)->getType()) {
769          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
770        } else {
771          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
772          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
773        }
774        Record.push_back(VE.getValueID(C->getOperand(0)));
775        Record.push_back(VE.getValueID(C->getOperand(1)));
776        Record.push_back(VE.getValueID(C->getOperand(2)));
777        break;
778      case Instruction::ICmp:
779      case Instruction::FCmp:
780        Code = bitc::CST_CODE_CE_CMP;
781        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
782        Record.push_back(VE.getValueID(C->getOperand(0)));
783        Record.push_back(VE.getValueID(C->getOperand(1)));
784        Record.push_back(CE->getPredicate());
785        break;
786      }
787    } else {
788      llvm_unreachable("Unknown constant!");
789    }
790    Stream.EmitRecord(Code, Record, AbbrevToUse);
791    Record.clear();
792  }
793
794  Stream.ExitBlock();
795}
796
797static void WriteModuleConstants(const ValueEnumerator &VE,
798                                 BitstreamWriter &Stream) {
799  const ValueEnumerator::ValueList &Vals = VE.getValues();
800
801  // Find the first constant to emit, which is the first non-globalvalue value.
802  // We know globalvalues have been emitted by WriteModuleInfo.
803  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
804    if (!isa<GlobalValue>(Vals[i].first)) {
805      WriteConstants(i, Vals.size(), VE, Stream, true);
806      return;
807    }
808  }
809}
810
811/// PushValueAndType - The file has to encode both the value and type id for
812/// many values, because we need to know what type to create for forward
813/// references.  However, most operands are not forward references, so this type
814/// field is not needed.
815///
816/// This function adds V's value ID to Vals.  If the value ID is higher than the
817/// instruction ID, then it is a forward reference, and it also includes the
818/// type ID.
819static bool PushValueAndType(const Value *V, unsigned InstID,
820                             SmallVector<unsigned, 64> &Vals,
821                             ValueEnumerator &VE) {
822  unsigned ValID = VE.getValueID(V);
823  Vals.push_back(ValID);
824  if (ValID >= InstID) {
825    Vals.push_back(VE.getTypeID(V->getType()));
826    return true;
827  }
828  return false;
829}
830
831/// WriteInstruction - Emit an instruction to the specified stream.
832static void WriteInstruction(const Instruction &I, unsigned InstID,
833                             ValueEnumerator &VE, BitstreamWriter &Stream,
834                             SmallVector<unsigned, 64> &Vals) {
835  unsigned Code = 0;
836  unsigned AbbrevToUse = 0;
837  switch (I.getOpcode()) {
838  default:
839    if (Instruction::isCast(I.getOpcode())) {
840      Code = bitc::FUNC_CODE_INST_CAST;
841      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
842        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
843      Vals.push_back(VE.getTypeID(I.getType()));
844      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
845    } else {
846      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
847      Code = bitc::FUNC_CODE_INST_BINOP;
848      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
849        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
850      Vals.push_back(VE.getValueID(I.getOperand(1)));
851      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
852      uint64_t Flags = GetOptimizationFlags(&I);
853      if (Flags != 0) {
854        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
855          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
856        Vals.push_back(Flags);
857      }
858    }
859    break;
860
861  case Instruction::GetElementPtr:
862    Code = bitc::FUNC_CODE_INST_GEP;
863    if (cast<GEPOperator>(&I)->isInBounds())
864      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
865    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
866      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
867    break;
868  case Instruction::ExtractValue: {
869    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
870    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
871    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
872    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
873      Vals.push_back(*i);
874    break;
875  }
876  case Instruction::InsertValue: {
877    Code = bitc::FUNC_CODE_INST_INSERTVAL;
878    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
879    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
880    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
881    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
882      Vals.push_back(*i);
883    break;
884  }
885  case Instruction::Select:
886    Code = bitc::FUNC_CODE_INST_VSELECT;
887    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
888    Vals.push_back(VE.getValueID(I.getOperand(2)));
889    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
890    break;
891  case Instruction::ExtractElement:
892    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
893    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
894    Vals.push_back(VE.getValueID(I.getOperand(1)));
895    break;
896  case Instruction::InsertElement:
897    Code = bitc::FUNC_CODE_INST_INSERTELT;
898    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
899    Vals.push_back(VE.getValueID(I.getOperand(1)));
900    Vals.push_back(VE.getValueID(I.getOperand(2)));
901    break;
902  case Instruction::ShuffleVector:
903    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
904    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
905    Vals.push_back(VE.getValueID(I.getOperand(1)));
906    Vals.push_back(VE.getValueID(I.getOperand(2)));
907    break;
908  case Instruction::ICmp:
909  case Instruction::FCmp:
910    // compare returning Int1Ty or vector of Int1Ty
911    Code = bitc::FUNC_CODE_INST_CMP2;
912    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
913    Vals.push_back(VE.getValueID(I.getOperand(1)));
914    Vals.push_back(cast<CmpInst>(I).getPredicate());
915    break;
916
917  case Instruction::Ret:
918    {
919      Code = bitc::FUNC_CODE_INST_RET;
920      unsigned NumOperands = I.getNumOperands();
921      if (NumOperands == 0)
922        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
923      else if (NumOperands == 1) {
924        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
925          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
926      } else {
927        for (unsigned i = 0, e = NumOperands; i != e; ++i)
928          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
929      }
930    }
931    break;
932  case Instruction::Br:
933    {
934      Code = bitc::FUNC_CODE_INST_BR;
935      BranchInst &II(cast<BranchInst>(I));
936      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
937      if (II.isConditional()) {
938        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
939        Vals.push_back(VE.getValueID(II.getCondition()));
940      }
941    }
942    break;
943  case Instruction::Switch:
944    Code = bitc::FUNC_CODE_INST_SWITCH;
945    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
946    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
947      Vals.push_back(VE.getValueID(I.getOperand(i)));
948    break;
949  case Instruction::Invoke: {
950    const InvokeInst *II = cast<InvokeInst>(&I);
951    const Value *Callee(II->getCalledValue());
952    const PointerType *PTy = cast<PointerType>(Callee->getType());
953    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
954    Code = bitc::FUNC_CODE_INST_INVOKE;
955
956    Vals.push_back(VE.getAttributeID(II->getAttributes()));
957    Vals.push_back(II->getCallingConv());
958    Vals.push_back(VE.getValueID(II->getNormalDest()));
959    Vals.push_back(VE.getValueID(II->getUnwindDest()));
960    PushValueAndType(Callee, InstID, Vals, VE);
961
962    // Emit value #'s for the fixed parameters.
963    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
964      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
965
966    // Emit type/value pairs for varargs params.
967    if (FTy->isVarArg()) {
968      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
969           i != e; ++i)
970        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
971    }
972    break;
973  }
974  case Instruction::Unwind:
975    Code = bitc::FUNC_CODE_INST_UNWIND;
976    break;
977  case Instruction::Unreachable:
978    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
979    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
980    break;
981
982  case Instruction::PHI:
983    Code = bitc::FUNC_CODE_INST_PHI;
984    Vals.push_back(VE.getTypeID(I.getType()));
985    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
986      Vals.push_back(VE.getValueID(I.getOperand(i)));
987    break;
988
989  case Instruction::Malloc:
990    Code = bitc::FUNC_CODE_INST_MALLOC;
991    Vals.push_back(VE.getTypeID(I.getType()));
992    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
993    Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
994    break;
995
996  case Instruction::Free:
997    Code = bitc::FUNC_CODE_INST_FREE;
998    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
999    break;
1000
1001  case Instruction::Alloca:
1002    Code = bitc::FUNC_CODE_INST_ALLOCA;
1003    Vals.push_back(VE.getTypeID(I.getType()));
1004    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1005    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1006    break;
1007
1008  case Instruction::Load:
1009    Code = bitc::FUNC_CODE_INST_LOAD;
1010    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1011      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1012
1013    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1014    Vals.push_back(cast<LoadInst>(I).isVolatile());
1015    break;
1016  case Instruction::Store:
1017    Code = bitc::FUNC_CODE_INST_STORE2;
1018    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1019    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1020    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1021    Vals.push_back(cast<StoreInst>(I).isVolatile());
1022    break;
1023  case Instruction::Call: {
1024    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1025    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1026
1027    Code = bitc::FUNC_CODE_INST_CALL;
1028
1029    const CallInst *CI = cast<CallInst>(&I);
1030    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1031    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1032    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1033
1034    // Emit value #'s for the fixed parameters.
1035    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1036      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1037
1038    // Emit type/value pairs for varargs params.
1039    if (FTy->isVarArg()) {
1040      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1041      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1042           i != e; ++i)
1043        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1044    }
1045    break;
1046  }
1047  case Instruction::VAArg:
1048    Code = bitc::FUNC_CODE_INST_VAARG;
1049    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1050    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1051    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1052    break;
1053  }
1054
1055  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1056  Vals.clear();
1057}
1058
1059// Emit names for globals/functions etc.
1060static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1061                                  const ValueEnumerator &VE,
1062                                  BitstreamWriter &Stream) {
1063  if (VST.empty()) return;
1064  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1065
1066  // FIXME: Set up the abbrev, we know how many values there are!
1067  // FIXME: We know if the type names can use 7-bit ascii.
1068  SmallVector<unsigned, 64> NameVals;
1069
1070  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1071       SI != SE; ++SI) {
1072
1073    const ValueName &Name = *SI;
1074
1075    // Figure out the encoding to use for the name.
1076    bool is7Bit = true;
1077    bool isChar6 = true;
1078    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1079         C != E; ++C) {
1080      if (isChar6)
1081        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1082      if ((unsigned char)*C & 128) {
1083        is7Bit = false;
1084        break;  // don't bother scanning the rest.
1085      }
1086    }
1087
1088    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1089
1090    // VST_ENTRY:   [valueid, namechar x N]
1091    // VST_BBENTRY: [bbid, namechar x N]
1092    unsigned Code;
1093    if (isa<BasicBlock>(SI->getValue())) {
1094      Code = bitc::VST_CODE_BBENTRY;
1095      if (isChar6)
1096        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1097    } else {
1098      Code = bitc::VST_CODE_ENTRY;
1099      if (isChar6)
1100        AbbrevToUse = VST_ENTRY_6_ABBREV;
1101      else if (is7Bit)
1102        AbbrevToUse = VST_ENTRY_7_ABBREV;
1103    }
1104
1105    NameVals.push_back(VE.getValueID(SI->getValue()));
1106    for (const char *P = Name.getKeyData(),
1107         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1108      NameVals.push_back((unsigned char)*P);
1109
1110    // Emit the finished record.
1111    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1112    NameVals.clear();
1113  }
1114  Stream.ExitBlock();
1115}
1116
1117/// WriteFunction - Emit a function body to the module stream.
1118static void WriteFunction(const Function &F, ValueEnumerator &VE,
1119                          BitstreamWriter &Stream) {
1120  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1121  VE.incorporateFunction(F);
1122
1123  SmallVector<unsigned, 64> Vals;
1124
1125  // Emit the number of basic blocks, so the reader can create them ahead of
1126  // time.
1127  Vals.push_back(VE.getBasicBlocks().size());
1128  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1129  Vals.clear();
1130
1131  // If there are function-local constants, emit them now.
1132  unsigned CstStart, CstEnd;
1133  VE.getFunctionConstantRange(CstStart, CstEnd);
1134  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1135
1136  // Keep a running idea of what the instruction ID is.
1137  unsigned InstID = CstEnd;
1138
1139  // Finally, emit all the instructions, in order.
1140  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1141    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1142         I != E; ++I) {
1143      WriteInstruction(*I, InstID, VE, Stream, Vals);
1144      if (I->getType() != Type::getVoidTy(F.getContext()))
1145        ++InstID;
1146    }
1147
1148  // Emit names for all the instructions etc.
1149  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1150
1151  VE.purgeFunction();
1152  Stream.ExitBlock();
1153}
1154
1155/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1156static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1157                                 const ValueEnumerator &VE,
1158                                 BitstreamWriter &Stream) {
1159  if (TST.empty()) return;
1160
1161  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1162
1163  // 7-bit fixed width VST_CODE_ENTRY strings.
1164  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1165  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1166  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1167                            Log2_32_Ceil(VE.getTypes().size()+1)));
1168  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1169  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1170  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1171
1172  SmallVector<unsigned, 64> NameVals;
1173
1174  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1175       TI != TE; ++TI) {
1176    // TST_ENTRY: [typeid, namechar x N]
1177    NameVals.push_back(VE.getTypeID(TI->second));
1178
1179    const std::string &Str = TI->first;
1180    bool is7Bit = true;
1181    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1182      NameVals.push_back((unsigned char)Str[i]);
1183      if (Str[i] & 128)
1184        is7Bit = false;
1185    }
1186
1187    // Emit the finished record.
1188    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1189    NameVals.clear();
1190  }
1191
1192  Stream.ExitBlock();
1193}
1194
1195// Emit blockinfo, which defines the standard abbreviations etc.
1196static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1197  // We only want to emit block info records for blocks that have multiple
1198  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1199  // blocks can defined their abbrevs inline.
1200  Stream.EnterBlockInfoBlock(2);
1201
1202  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1203    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1204    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1205    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1206    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1207    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1208    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1209                                   Abbv) != VST_ENTRY_8_ABBREV)
1210      llvm_unreachable("Unexpected abbrev ordering!");
1211  }
1212
1213  { // 7-bit fixed width VST_ENTRY strings.
1214    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1215    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1216    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1217    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1218    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1219    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1220                                   Abbv) != VST_ENTRY_7_ABBREV)
1221      llvm_unreachable("Unexpected abbrev ordering!");
1222  }
1223  { // 6-bit char6 VST_ENTRY strings.
1224    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1225    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1226    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1227    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1228    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1229    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1230                                   Abbv) != VST_ENTRY_6_ABBREV)
1231      llvm_unreachable("Unexpected abbrev ordering!");
1232  }
1233  { // 6-bit char6 VST_BBENTRY strings.
1234    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1235    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1236    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1237    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1238    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1239    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1240                                   Abbv) != VST_BBENTRY_6_ABBREV)
1241      llvm_unreachable("Unexpected abbrev ordering!");
1242  }
1243
1244
1245
1246  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1247    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1248    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1249    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1250                              Log2_32_Ceil(VE.getTypes().size()+1)));
1251    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1252                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1253      llvm_unreachable("Unexpected abbrev ordering!");
1254  }
1255
1256  { // INTEGER abbrev for CONSTANTS_BLOCK.
1257    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1258    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1259    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1260    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1261                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1262      llvm_unreachable("Unexpected abbrev ordering!");
1263  }
1264
1265  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1266    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1267    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1268    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1269    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1270                              Log2_32_Ceil(VE.getTypes().size()+1)));
1271    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1272
1273    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1274                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1275      llvm_unreachable("Unexpected abbrev ordering!");
1276  }
1277  { // NULL abbrev for CONSTANTS_BLOCK.
1278    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1279    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1280    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1281                                   Abbv) != CONSTANTS_NULL_Abbrev)
1282      llvm_unreachable("Unexpected abbrev ordering!");
1283  }
1284
1285  // FIXME: This should only use space for first class types!
1286
1287  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1288    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1289    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1290    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1291    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1292    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1293    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1294                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1295      llvm_unreachable("Unexpected abbrev ordering!");
1296  }
1297  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1298    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1299    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1300    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1301    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1302    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1303    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1304                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1305      llvm_unreachable("Unexpected abbrev ordering!");
1306  }
1307  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1308    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1309    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1310    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1311    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1312    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1313    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1314    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1315                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1316      llvm_unreachable("Unexpected abbrev ordering!");
1317  }
1318  { // INST_CAST abbrev for FUNCTION_BLOCK.
1319    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1320    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1321    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1322    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1323                              Log2_32_Ceil(VE.getTypes().size()+1)));
1324    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1325    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1326                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1327      llvm_unreachable("Unexpected abbrev ordering!");
1328  }
1329
1330  { // INST_RET abbrev for FUNCTION_BLOCK.
1331    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1332    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1333    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1334                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1335      llvm_unreachable("Unexpected abbrev ordering!");
1336  }
1337  { // INST_RET abbrev for FUNCTION_BLOCK.
1338    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1339    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1340    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1341    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1342                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1343      llvm_unreachable("Unexpected abbrev ordering!");
1344  }
1345  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1346    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1347    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1348    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1349                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1350      llvm_unreachable("Unexpected abbrev ordering!");
1351  }
1352
1353  Stream.ExitBlock();
1354}
1355
1356
1357/// WriteModule - Emit the specified module to the bitstream.
1358static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1359  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1360
1361  // Emit the version number if it is non-zero.
1362  if (CurVersion) {
1363    SmallVector<unsigned, 1> Vals;
1364    Vals.push_back(CurVersion);
1365    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1366  }
1367
1368  // Analyze the module, enumerating globals, functions, etc.
1369  ValueEnumerator VE(M);
1370
1371  // Emit blockinfo, which defines the standard abbreviations etc.
1372  WriteBlockInfo(VE, Stream);
1373
1374  // Emit information about parameter attributes.
1375  WriteAttributeTable(VE, Stream);
1376
1377  // Emit information describing all of the types in the module.
1378  WriteTypeTable(VE, Stream);
1379
1380  // Emit top-level description of module, including target triple, inline asm,
1381  // descriptors for global variables, and function prototype info.
1382  WriteModuleInfo(M, VE, Stream);
1383
1384  // Emit constants.
1385  WriteModuleConstants(VE, Stream);
1386
1387  // Emit metadata.
1388  WriteModuleMetadata(VE, Stream);
1389
1390  // Emit function bodies.
1391  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1392    if (!I->isDeclaration())
1393      WriteFunction(*I, VE, Stream);
1394
1395  // Emit the type symbol table information.
1396  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1397
1398  // Emit names for globals/functions etc.
1399  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1400
1401  Stream.ExitBlock();
1402}
1403
1404/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1405/// header and trailer to make it compatible with the system archiver.  To do
1406/// this we emit the following header, and then emit a trailer that pads the
1407/// file out to be a multiple of 16 bytes.
1408///
1409/// struct bc_header {
1410///   uint32_t Magic;         // 0x0B17C0DE
1411///   uint32_t Version;       // Version, currently always 0.
1412///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1413///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1414///   uint32_t CPUType;       // CPU specifier.
1415///   ... potentially more later ...
1416/// };
1417enum {
1418  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1419  DarwinBCHeaderSize = 5*4
1420};
1421
1422static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1423                               const std::string &TT) {
1424  unsigned CPUType = ~0U;
1425
1426  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1427  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1428  // specific constants here because they are implicitly part of the Darwin ABI.
1429  enum {
1430    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1431    DARWIN_CPU_TYPE_X86        = 7,
1432    DARWIN_CPU_TYPE_POWERPC    = 18
1433  };
1434
1435  if (TT.find("x86_64-") == 0)
1436    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1437  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1438           TT[4] == '-' && TT[1] - '3' < 6)
1439    CPUType = DARWIN_CPU_TYPE_X86;
1440  else if (TT.find("powerpc-") == 0)
1441    CPUType = DARWIN_CPU_TYPE_POWERPC;
1442  else if (TT.find("powerpc64-") == 0)
1443    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1444
1445  // Traditional Bitcode starts after header.
1446  unsigned BCOffset = DarwinBCHeaderSize;
1447
1448  Stream.Emit(0x0B17C0DE, 32);
1449  Stream.Emit(0         , 32);  // Version.
1450  Stream.Emit(BCOffset  , 32);
1451  Stream.Emit(0         , 32);  // Filled in later.
1452  Stream.Emit(CPUType   , 32);
1453}
1454
1455/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1456/// finalize the header.
1457static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1458  // Update the size field in the header.
1459  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1460
1461  // If the file is not a multiple of 16 bytes, insert dummy padding.
1462  while (BufferSize & 15) {
1463    Stream.Emit(0, 8);
1464    ++BufferSize;
1465  }
1466}
1467
1468
1469/// WriteBitcodeToFile - Write the specified module to the specified output
1470/// stream.
1471void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1472  raw_os_ostream RawOut(Out);
1473  // If writing to stdout, set binary mode.
1474  if (llvm::cout == Out)
1475    sys::Program::ChangeStdoutToBinary();
1476  WriteBitcodeToFile(M, RawOut);
1477}
1478
1479/// WriteBitcodeToFile - Write the specified module to the specified output
1480/// stream.
1481void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1482  std::vector<unsigned char> Buffer;
1483  BitstreamWriter Stream(Buffer);
1484
1485  Buffer.reserve(256*1024);
1486
1487  WriteBitcodeToStream( M, Stream );
1488
1489  // If writing to stdout, set binary mode.
1490  if (&llvm::outs() == &Out)
1491    sys::Program::ChangeStdoutToBinary();
1492
1493  // Write the generated bitstream to "Out".
1494  Out.write((char*)&Buffer.front(), Buffer.size());
1495
1496  // Make sure it hits disk now.
1497  Out.flush();
1498}
1499
1500/// WriteBitcodeToStream - Write the specified module to the specified output
1501/// stream.
1502void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1503  // If this is darwin, emit a file header and trailer if needed.
1504  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1505  if (isDarwin)
1506    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1507
1508  // Emit the file header.
1509  Stream.Emit((unsigned)'B', 8);
1510  Stream.Emit((unsigned)'C', 8);
1511  Stream.Emit(0x0, 4);
1512  Stream.Emit(0xC, 4);
1513  Stream.Emit(0xE, 4);
1514  Stream.Emit(0xD, 4);
1515
1516  // Emit the module.
1517  WriteModule(M, Stream);
1518
1519  if (isDarwin)
1520    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1521}
1522