BitcodeWriter.cpp revision 2359e5193aa9fff9e005e99074ed40ea5d08f838 
1//===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Bitcode writer implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Bitcode/ReaderWriter.h"
15#include "llvm/Bitcode/BitstreamWriter.h"
16#include "llvm/Bitcode/LLVMBitCodes.h"
17#include "ValueEnumerator.h"
18#include "llvm/Constants.h"
19#include "llvm/DerivedTypes.h"
20#include "llvm/InlineAsm.h"
21#include "llvm/Instructions.h"
22#include "llvm/Module.h"
23#include "llvm/Operator.h"
24#include "llvm/TypeSymbolTable.h"
25#include "llvm/ValueSymbolTable.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/MathExtras.h"
28#include "llvm/Support/raw_ostream.h"
29#include "llvm/System/Program.h"
30using namespace llvm;
31
32/// These are manifest constants used by the bitcode writer. They do not need to
33/// be kept in sync with the reader, but need to be consistent within this file.
34enum {
35  CurVersion = 0,
36
37  // VALUE_SYMTAB_BLOCK abbrev id's.
38  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
39  VST_ENTRY_7_ABBREV,
40  VST_ENTRY_6_ABBREV,
41  VST_BBENTRY_6_ABBREV,
42
43  // CONSTANTS_BLOCK abbrev id's.
44  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
45  CONSTANTS_INTEGER_ABBREV,
46  CONSTANTS_CE_CAST_Abbrev,
47  CONSTANTS_NULL_Abbrev,
48
49  // FUNCTION_BLOCK abbrev id's.
50  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
51  FUNCTION_INST_BINOP_ABBREV,
52  FUNCTION_INST_BINOP_FLAGS_ABBREV,
53  FUNCTION_INST_CAST_ABBREV,
54  FUNCTION_INST_RET_VOID_ABBREV,
55  FUNCTION_INST_RET_VAL_ABBREV,
56  FUNCTION_INST_UNREACHABLE_ABBREV
57};
58
59
60static unsigned GetEncodedCastOpcode(unsigned Opcode) {
61  switch (Opcode) {
62  default: llvm_unreachable("Unknown cast instruction!");
63  case Instruction::Trunc   : return bitc::CAST_TRUNC;
64  case Instruction::ZExt    : return bitc::CAST_ZEXT;
65  case Instruction::SExt    : return bitc::CAST_SEXT;
66  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
67  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
68  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
69  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
70  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
71  case Instruction::FPExt   : return bitc::CAST_FPEXT;
72  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
73  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
74  case Instruction::BitCast : return bitc::CAST_BITCAST;
75  }
76}
77
78static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
79  switch (Opcode) {
80  default: llvm_unreachable("Unknown binary instruction!");
81  case Instruction::Add:
82  case Instruction::FAdd: return bitc::BINOP_ADD;
83  case Instruction::Sub:
84  case Instruction::FSub: return bitc::BINOP_SUB;
85  case Instruction::Mul:
86  case Instruction::FMul: return bitc::BINOP_MUL;
87  case Instruction::UDiv: return bitc::BINOP_UDIV;
88  case Instruction::FDiv:
89  case Instruction::SDiv: return bitc::BINOP_SDIV;
90  case Instruction::URem: return bitc::BINOP_UREM;
91  case Instruction::FRem:
92  case Instruction::SRem: return bitc::BINOP_SREM;
93  case Instruction::Shl:  return bitc::BINOP_SHL;
94  case Instruction::LShr: return bitc::BINOP_LSHR;
95  case Instruction::AShr: return bitc::BINOP_ASHR;
96  case Instruction::And:  return bitc::BINOP_AND;
97  case Instruction::Or:   return bitc::BINOP_OR;
98  case Instruction::Xor:  return bitc::BINOP_XOR;
99  }
100}
101
102
103
104static void WriteStringRecord(unsigned Code, const std::string &Str,
105                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
106  SmallVector<unsigned, 64> Vals;
107
108  // Code: [strchar x N]
109  for (unsigned i = 0, e = Str.size(); i != e; ++i)
110    Vals.push_back(Str[i]);
111
112  // Emit the finished record.
113  Stream.EmitRecord(Code, Vals, AbbrevToUse);
114}
115
116// Emit information about parameter attributes.
117static void WriteAttributeTable(const ValueEnumerator &VE,
118                                BitstreamWriter &Stream) {
119  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
120  if (Attrs.empty()) return;
121
122  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
123
124  SmallVector<uint64_t, 64> Record;
125  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
126    const AttrListPtr &A = Attrs[i];
127    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
128      const AttributeWithIndex &PAWI = A.getSlot(i);
129      Record.push_back(PAWI.Index);
130
131      // FIXME: remove in LLVM 3.0
132      // Store the alignment in the bitcode as a 16-bit raw value instead of a
133      // 5-bit log2 encoded value. Shift the bits above the alignment up by
134      // 11 bits.
135      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
136      if (PAWI.Attrs & Attribute::Alignment)
137        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
138      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
139
140      Record.push_back(FauxAttr);
141    }
142
143    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
144    Record.clear();
145  }
146
147  Stream.ExitBlock();
148}
149
150/// WriteTypeTable - Write out the type table for a module.
151static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
152  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
153
154  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
155  SmallVector<uint64_t, 64> TypeVals;
156
157  // Abbrev for TYPE_CODE_POINTER.
158  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
159  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
160  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
161                            Log2_32_Ceil(VE.getTypes().size()+1)));
162  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
163  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
164
165  // Abbrev for TYPE_CODE_FUNCTION.
166  Abbv = new BitCodeAbbrev();
167  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
168  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
169  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
171  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
172                            Log2_32_Ceil(VE.getTypes().size()+1)));
173  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
174
175  // Abbrev for TYPE_CODE_STRUCT.
176  Abbv = new BitCodeAbbrev();
177  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
178  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
179  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
181                            Log2_32_Ceil(VE.getTypes().size()+1)));
182  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
183
184  // Abbrev for TYPE_CODE_UNION.
185  Abbv = new BitCodeAbbrev();
186  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_UNION));
187  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
188  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
189                            Log2_32_Ceil(VE.getTypes().size()+1)));
190  unsigned UnionAbbrev = Stream.EmitAbbrev(Abbv);
191
192  // Abbrev for TYPE_CODE_ARRAY.
193  Abbv = new BitCodeAbbrev();
194  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
195  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
196  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
197                            Log2_32_Ceil(VE.getTypes().size()+1)));
198  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
199
200  // Emit an entry count so the reader can reserve space.
201  TypeVals.push_back(TypeList.size());
202  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
203  TypeVals.clear();
204
205  // Loop over all of the types, emitting each in turn.
206  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
207    const Type *T = TypeList[i].first;
208    int AbbrevToUse = 0;
209    unsigned Code = 0;
210
211    switch (T->getTypeID()) {
212    default: llvm_unreachable("Unknown type!");
213    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
214    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
215    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
216    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
217    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
218    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
219    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
220    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
221    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
222    case Type::IntegerTyID:
223      // INTEGER: [width]
224      Code = bitc::TYPE_CODE_INTEGER;
225      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
226      break;
227    case Type::PointerTyID: {
228      const PointerType *PTy = cast<PointerType>(T);
229      // POINTER: [pointee type, address space]
230      Code = bitc::TYPE_CODE_POINTER;
231      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
232      unsigned AddressSpace = PTy->getAddressSpace();
233      TypeVals.push_back(AddressSpace);
234      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
235      break;
236    }
237    case Type::FunctionTyID: {
238      const FunctionType *FT = cast<FunctionType>(T);
239      // FUNCTION: [isvararg, attrid, retty, paramty x N]
240      Code = bitc::TYPE_CODE_FUNCTION;
241      TypeVals.push_back(FT->isVarArg());
242      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
243      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
244      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
245        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
246      AbbrevToUse = FunctionAbbrev;
247      break;
248    }
249    case Type::StructTyID: {
250      const StructType *ST = cast<StructType>(T);
251      // STRUCT: [ispacked, eltty x N]
252      Code = bitc::TYPE_CODE_STRUCT;
253      TypeVals.push_back(ST->isPacked());
254      // Output all of the element types.
255      for (StructType::element_iterator I = ST->element_begin(),
256           E = ST->element_end(); I != E; ++I)
257        TypeVals.push_back(VE.getTypeID(*I));
258      AbbrevToUse = StructAbbrev;
259      break;
260    }
261    case Type::UnionTyID: {
262      const UnionType *UT = cast<UnionType>(T);
263      // UNION: [eltty x N]
264      Code = bitc::TYPE_CODE_UNION;
265      // Output all of the element types.
266      for (UnionType::element_iterator I = UT->element_begin(),
267           E = UT->element_end(); I != E; ++I)
268        TypeVals.push_back(VE.getTypeID(*I));
269      AbbrevToUse = UnionAbbrev;
270      break;
271    }
272    case Type::ArrayTyID: {
273      const ArrayType *AT = cast<ArrayType>(T);
274      // ARRAY: [numelts, eltty]
275      Code = bitc::TYPE_CODE_ARRAY;
276      TypeVals.push_back(AT->getNumElements());
277      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
278      AbbrevToUse = ArrayAbbrev;
279      break;
280    }
281    case Type::VectorTyID: {
282      const VectorType *VT = cast<VectorType>(T);
283      // VECTOR [numelts, eltty]
284      Code = bitc::TYPE_CODE_VECTOR;
285      TypeVals.push_back(VT->getNumElements());
286      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
287      break;
288    }
289    }
290
291    // Emit the finished record.
292    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
293    TypeVals.clear();
294  }
295
296  Stream.ExitBlock();
297}
298
299static unsigned getEncodedLinkage(const GlobalValue *GV) {
300  switch (GV->getLinkage()) {
301  default: llvm_unreachable("Invalid linkage!");
302  case GlobalValue::ExternalLinkage:            return 0;
303  case GlobalValue::WeakAnyLinkage:             return 1;
304  case GlobalValue::AppendingLinkage:           return 2;
305  case GlobalValue::InternalLinkage:            return 3;
306  case GlobalValue::LinkOnceAnyLinkage:         return 4;
307  case GlobalValue::DLLImportLinkage:           return 5;
308  case GlobalValue::DLLExportLinkage:           return 6;
309  case GlobalValue::ExternalWeakLinkage:        return 7;
310  case GlobalValue::CommonLinkage:              return 8;
311  case GlobalValue::PrivateLinkage:             return 9;
312  case GlobalValue::WeakODRLinkage:             return 10;
313  case GlobalValue::LinkOnceODRLinkage:         return 11;
314  case GlobalValue::AvailableExternallyLinkage: return 12;
315  case GlobalValue::LinkerPrivateLinkage:       return 13;
316  case GlobalValue::LinkerPrivateWeakLinkage:   return 14;
317  }
318}
319
320static unsigned getEncodedVisibility(const GlobalValue *GV) {
321  switch (GV->getVisibility()) {
322  default: llvm_unreachable("Invalid visibility!");
323  case GlobalValue::DefaultVisibility:   return 0;
324  case GlobalValue::HiddenVisibility:    return 1;
325  case GlobalValue::ProtectedVisibility: return 2;
326  }
327}
328
329// Emit top-level description of module, including target triple, inline asm,
330// descriptors for global variables, and function prototype info.
331static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
332                            BitstreamWriter &Stream) {
333  // Emit the list of dependent libraries for the Module.
334  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
335    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
336
337  // Emit various pieces of data attached to a module.
338  if (!M->getTargetTriple().empty())
339    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
340                      0/*TODO*/, Stream);
341  if (!M->getDataLayout().empty())
342    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
343                      0/*TODO*/, Stream);
344  if (!M->getModuleInlineAsm().empty())
345    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
346                      0/*TODO*/, Stream);
347
348  // Emit information about sections and GC, computing how many there are. Also
349  // compute the maximum alignment value.
350  std::map<std::string, unsigned> SectionMap;
351  std::map<std::string, unsigned> GCMap;
352  unsigned MaxAlignment = 0;
353  unsigned MaxGlobalType = 0;
354  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
355       GV != E; ++GV) {
356    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
357    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
358
359    if (!GV->hasSection()) continue;
360    // Give section names unique ID's.
361    unsigned &Entry = SectionMap[GV->getSection()];
362    if (Entry != 0) continue;
363    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
364                      0/*TODO*/, Stream);
365    Entry = SectionMap.size();
366  }
367  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
368    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
369    if (F->hasSection()) {
370      // Give section names unique ID's.
371      unsigned &Entry = SectionMap[F->getSection()];
372      if (!Entry) {
373        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
374                          0/*TODO*/, Stream);
375        Entry = SectionMap.size();
376      }
377    }
378    if (F->hasGC()) {
379      // Same for GC names.
380      unsigned &Entry = GCMap[F->getGC()];
381      if (!Entry) {
382        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
383                          0/*TODO*/, Stream);
384        Entry = GCMap.size();
385      }
386    }
387  }
388
389  // Emit abbrev for globals, now that we know # sections and max alignment.
390  unsigned SimpleGVarAbbrev = 0;
391  if (!M->global_empty()) {
392    // Add an abbrev for common globals with no visibility or thread localness.
393    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
394    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
395    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
396                              Log2_32_Ceil(MaxGlobalType+1)));
397    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
398    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
399    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
400    if (MaxAlignment == 0)                                      // Alignment.
401      Abbv->Add(BitCodeAbbrevOp(0));
402    else {
403      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
404      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
405                               Log2_32_Ceil(MaxEncAlignment+1)));
406    }
407    if (SectionMap.empty())                                    // Section.
408      Abbv->Add(BitCodeAbbrevOp(0));
409    else
410      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
411                               Log2_32_Ceil(SectionMap.size()+1)));
412    // Don't bother emitting vis + thread local.
413    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
414  }
415
416  // Emit the global variable information.
417  SmallVector<unsigned, 64> Vals;
418  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
419       GV != E; ++GV) {
420    unsigned AbbrevToUse = 0;
421
422    // GLOBALVAR: [type, isconst, initid,
423    //             linkage, alignment, section, visibility, threadlocal]
424    Vals.push_back(VE.getTypeID(GV->getType()));
425    Vals.push_back(GV->isConstant());
426    Vals.push_back(GV->isDeclaration() ? 0 :
427                   (VE.getValueID(GV->getInitializer()) + 1));
428    Vals.push_back(getEncodedLinkage(GV));
429    Vals.push_back(Log2_32(GV->getAlignment())+1);
430    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
431    if (GV->isThreadLocal() ||
432        GV->getVisibility() != GlobalValue::DefaultVisibility) {
433      Vals.push_back(getEncodedVisibility(GV));
434      Vals.push_back(GV->isThreadLocal());
435    } else {
436      AbbrevToUse = SimpleGVarAbbrev;
437    }
438
439    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
440    Vals.clear();
441  }
442
443  // Emit the function proto information.
444  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
445    // FUNCTION:  [type, callingconv, isproto, paramattr,
446    //             linkage, alignment, section, visibility, gc]
447    Vals.push_back(VE.getTypeID(F->getType()));
448    Vals.push_back(F->getCallingConv());
449    Vals.push_back(F->isDeclaration());
450    Vals.push_back(getEncodedLinkage(F));
451    Vals.push_back(VE.getAttributeID(F->getAttributes()));
452    Vals.push_back(Log2_32(F->getAlignment())+1);
453    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
454    Vals.push_back(getEncodedVisibility(F));
455    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
456
457    unsigned AbbrevToUse = 0;
458    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
459    Vals.clear();
460  }
461
462
463  // Emit the alias information.
464  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
465       AI != E; ++AI) {
466    Vals.push_back(VE.getTypeID(AI->getType()));
467    Vals.push_back(VE.getValueID(AI->getAliasee()));
468    Vals.push_back(getEncodedLinkage(AI));
469    Vals.push_back(getEncodedVisibility(AI));
470    unsigned AbbrevToUse = 0;
471    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
472    Vals.clear();
473  }
474}
475
476static uint64_t GetOptimizationFlags(const Value *V) {
477  uint64_t Flags = 0;
478
479  if (const OverflowingBinaryOperator *OBO =
480        dyn_cast<OverflowingBinaryOperator>(V)) {
481    if (OBO->hasNoSignedWrap())
482      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
483    if (OBO->hasNoUnsignedWrap())
484      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
485  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
486    if (Div->isExact())
487      Flags |= 1 << bitc::SDIV_EXACT;
488  }
489
490  return Flags;
491}
492
493static void WriteMDNode(const MDNode *N,
494                        const ValueEnumerator &VE,
495                        BitstreamWriter &Stream,
496                        SmallVector<uint64_t, 64> &Record) {
497  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
498    if (N->getOperand(i)) {
499      Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
500      Record.push_back(VE.getValueID(N->getOperand(i)));
501    } else {
502      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
503      Record.push_back(0);
504    }
505  }
506  unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
507                                           bitc::METADATA_NODE;
508  Stream.EmitRecord(MDCode, Record, 0);
509  Record.clear();
510}
511
512static void WriteModuleMetadata(const Module *M,
513                                const ValueEnumerator &VE,
514                                BitstreamWriter &Stream) {
515  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
516  bool StartedMetadataBlock = false;
517  unsigned MDSAbbrev = 0;
518  SmallVector<uint64_t, 64> Record;
519  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
520
521    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
522      if (!N->isFunctionLocal() || !N->getFunction()) {
523        if (!StartedMetadataBlock) {
524          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
525          StartedMetadataBlock = true;
526        }
527        WriteMDNode(N, VE, Stream, Record);
528      }
529    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
530      if (!StartedMetadataBlock)  {
531        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
532
533        // Abbrev for METADATA_STRING.
534        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
535        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
536        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
537        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
538        MDSAbbrev = Stream.EmitAbbrev(Abbv);
539        StartedMetadataBlock = true;
540      }
541
542      // Code: [strchar x N]
543      Record.append(MDS->begin(), MDS->end());
544
545      // Emit the finished record.
546      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
547      Record.clear();
548    }
549  }
550
551  // Write named metadata.
552  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
553       E = M->named_metadata_end(); I != E; ++I) {
554    const NamedMDNode *NMD = I;
555    if (!StartedMetadataBlock)  {
556      Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
557      StartedMetadataBlock = true;
558    }
559
560    // Write name.
561    StringRef Str = NMD->getName();
562    for (unsigned i = 0, e = Str.size(); i != e; ++i)
563      Record.push_back(Str[i]);
564    Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
565    Record.clear();
566
567    // Write named metadata operands.
568    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
569      Record.push_back(VE.getValueID(NMD->getOperand(i)));
570    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
571    Record.clear();
572  }
573
574  if (StartedMetadataBlock)
575    Stream.ExitBlock();
576}
577
578static void WriteFunctionLocalMetadata(const Function &F,
579                                       const ValueEnumerator &VE,
580                                       BitstreamWriter &Stream) {
581  bool StartedMetadataBlock = false;
582  SmallVector<uint64_t, 64> Record;
583  const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
584  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
585    if (const MDNode *N = Vals[i])
586      if (N->isFunctionLocal() && N->getFunction() == &F) {
587        if (!StartedMetadataBlock) {
588          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
589          StartedMetadataBlock = true;
590        }
591        WriteMDNode(N, VE, Stream, Record);
592      }
593
594  if (StartedMetadataBlock)
595    Stream.ExitBlock();
596}
597
598static void WriteMetadataAttachment(const Function &F,
599                                    const ValueEnumerator &VE,
600                                    BitstreamWriter &Stream) {
601  Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
602
603  SmallVector<uint64_t, 64> Record;
604
605  // Write metadata attachments
606  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
607  SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
608
609  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
610    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
611         I != E; ++I) {
612      MDs.clear();
613      I->getAllMetadataOtherThanDebugLoc(MDs);
614
615      // If no metadata, ignore instruction.
616      if (MDs.empty()) continue;
617
618      Record.push_back(VE.getInstructionID(I));
619
620      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
621        Record.push_back(MDs[i].first);
622        Record.push_back(VE.getValueID(MDs[i].second));
623      }
624      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
625      Record.clear();
626    }
627
628  Stream.ExitBlock();
629}
630
631static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
632  SmallVector<uint64_t, 64> Record;
633
634  // Write metadata kinds
635  // METADATA_KIND - [n x [id, name]]
636  SmallVector<StringRef, 4> Names;
637  M->getMDKindNames(Names);
638
639  if (Names.empty()) return;
640
641  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
642
643  for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
644    Record.push_back(MDKindID);
645    StringRef KName = Names[MDKindID];
646    Record.append(KName.begin(), KName.end());
647
648    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
649    Record.clear();
650  }
651
652  Stream.ExitBlock();
653}
654
655static void WriteConstants(unsigned FirstVal, unsigned LastVal,
656                           const ValueEnumerator &VE,
657                           BitstreamWriter &Stream, bool isGlobal) {
658  if (FirstVal == LastVal) return;
659
660  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
661
662  unsigned AggregateAbbrev = 0;
663  unsigned String8Abbrev = 0;
664  unsigned CString7Abbrev = 0;
665  unsigned CString6Abbrev = 0;
666  // If this is a constant pool for the module, emit module-specific abbrevs.
667  if (isGlobal) {
668    // Abbrev for CST_CODE_AGGREGATE.
669    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
670    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
671    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
672    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
673    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
674
675    // Abbrev for CST_CODE_STRING.
676    Abbv = new BitCodeAbbrev();
677    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
678    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
679    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
680    String8Abbrev = Stream.EmitAbbrev(Abbv);
681    // Abbrev for CST_CODE_CSTRING.
682    Abbv = new BitCodeAbbrev();
683    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
684    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
685    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
686    CString7Abbrev = Stream.EmitAbbrev(Abbv);
687    // Abbrev for CST_CODE_CSTRING.
688    Abbv = new BitCodeAbbrev();
689    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
690    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
691    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
692    CString6Abbrev = Stream.EmitAbbrev(Abbv);
693  }
694
695  SmallVector<uint64_t, 64> Record;
696
697  const ValueEnumerator::ValueList &Vals = VE.getValues();
698  const Type *LastTy = 0;
699  for (unsigned i = FirstVal; i != LastVal; ++i) {
700    const Value *V = Vals[i].first;
701    // If we need to switch types, do so now.
702    if (V->getType() != LastTy) {
703      LastTy = V->getType();
704      Record.push_back(VE.getTypeID(LastTy));
705      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
706                        CONSTANTS_SETTYPE_ABBREV);
707      Record.clear();
708    }
709
710    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
711      Record.push_back(unsigned(IA->hasSideEffects()) |
712                       unsigned(IA->isAlignStack()) << 1);
713
714      // Add the asm string.
715      const std::string &AsmStr = IA->getAsmString();
716      Record.push_back(AsmStr.size());
717      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
718        Record.push_back(AsmStr[i]);
719
720      // Add the constraint string.
721      const std::string &ConstraintStr = IA->getConstraintString();
722      Record.push_back(ConstraintStr.size());
723      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
724        Record.push_back(ConstraintStr[i]);
725      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
726      Record.clear();
727      continue;
728    }
729    const Constant *C = cast<Constant>(V);
730    unsigned Code = -1U;
731    unsigned AbbrevToUse = 0;
732    if (C->isNullValue()) {
733      Code = bitc::CST_CODE_NULL;
734    } else if (isa<UndefValue>(C)) {
735      Code = bitc::CST_CODE_UNDEF;
736    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
737      if (IV->getBitWidth() <= 64) {
738        uint64_t V = IV->getSExtValue();
739        if ((int64_t)V >= 0)
740          Record.push_back(V << 1);
741        else
742          Record.push_back((-V << 1) | 1);
743        Code = bitc::CST_CODE_INTEGER;
744        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
745      } else {                             // Wide integers, > 64 bits in size.
746        // We have an arbitrary precision integer value to write whose
747        // bit width is > 64. However, in canonical unsigned integer
748        // format it is likely that the high bits are going to be zero.
749        // So, we only write the number of active words.
750        unsigned NWords = IV->getValue().getActiveWords();
751        const uint64_t *RawWords = IV->getValue().getRawData();
752        for (unsigned i = 0; i != NWords; ++i) {
753          int64_t V = RawWords[i];
754          if (V >= 0)
755            Record.push_back(V << 1);
756          else
757            Record.push_back((-V << 1) | 1);
758        }
759        Code = bitc::CST_CODE_WIDE_INTEGER;
760      }
761    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
762      Code = bitc::CST_CODE_FLOAT;
763      const Type *Ty = CFP->getType();
764      if (Ty->isFloatTy() || Ty->isDoubleTy()) {
765        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
766      } else if (Ty->isX86_FP80Ty()) {
767        // api needed to prevent premature destruction
768        // bits are not in the same order as a normal i80 APInt, compensate.
769        APInt api = CFP->getValueAPF().bitcastToAPInt();
770        const uint64_t *p = api.getRawData();
771        Record.push_back((p[1] << 48) | (p[0] >> 16));
772        Record.push_back(p[0] & 0xffffLL);
773      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
774        APInt api = CFP->getValueAPF().bitcastToAPInt();
775        const uint64_t *p = api.getRawData();
776        Record.push_back(p[0]);
777        Record.push_back(p[1]);
778      } else {
779        assert (0 && "Unknown FP type!");
780      }
781    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
782      const ConstantArray *CA = cast<ConstantArray>(C);
783      // Emit constant strings specially.
784      unsigned NumOps = CA->getNumOperands();
785      // If this is a null-terminated string, use the denser CSTRING encoding.
786      if (CA->getOperand(NumOps-1)->isNullValue()) {
787        Code = bitc::CST_CODE_CSTRING;
788        --NumOps;  // Don't encode the null, which isn't allowed by char6.
789      } else {
790        Code = bitc::CST_CODE_STRING;
791        AbbrevToUse = String8Abbrev;
792      }
793      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
794      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
795      for (unsigned i = 0; i != NumOps; ++i) {
796        unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
797        Record.push_back(V);
798        isCStr7 &= (V & 128) == 0;
799        if (isCStrChar6)
800          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
801      }
802
803      if (isCStrChar6)
804        AbbrevToUse = CString6Abbrev;
805      else if (isCStr7)
806        AbbrevToUse = CString7Abbrev;
807    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
808               isa<ConstantVector>(V)) {
809      Code = bitc::CST_CODE_AGGREGATE;
810      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
811        Record.push_back(VE.getValueID(C->getOperand(i)));
812      AbbrevToUse = AggregateAbbrev;
813    } else if (isa<ConstantUnion>(C)) {
814      Code = bitc::CST_CODE_AGGREGATE;
815
816      // Unions only have one entry but we must send type along with it.
817      const Type *EntryKind = C->getOperand(0)->getType();
818
819      const UnionType *UnTy = cast<UnionType>(C->getType());
820      int UnionIndex = UnTy->getElementTypeIndex(EntryKind);
821      assert(UnionIndex != -1 && "Constant union contains invalid entry");
822
823      Record.push_back(UnionIndex);
824      Record.push_back(VE.getValueID(C->getOperand(0)));
825
826      AbbrevToUse = AggregateAbbrev;
827    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
828      switch (CE->getOpcode()) {
829      default:
830        if (Instruction::isCast(CE->getOpcode())) {
831          Code = bitc::CST_CODE_CE_CAST;
832          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
833          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
834          Record.push_back(VE.getValueID(C->getOperand(0)));
835          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
836        } else {
837          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
838          Code = bitc::CST_CODE_CE_BINOP;
839          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
840          Record.push_back(VE.getValueID(C->getOperand(0)));
841          Record.push_back(VE.getValueID(C->getOperand(1)));
842          uint64_t Flags = GetOptimizationFlags(CE);
843          if (Flags != 0)
844            Record.push_back(Flags);
845        }
846        break;
847      case Instruction::GetElementPtr:
848        Code = bitc::CST_CODE_CE_GEP;
849        if (cast<GEPOperator>(C)->isInBounds())
850          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
851        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
852          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
853          Record.push_back(VE.getValueID(C->getOperand(i)));
854        }
855        break;
856      case Instruction::Select:
857        Code = bitc::CST_CODE_CE_SELECT;
858        Record.push_back(VE.getValueID(C->getOperand(0)));
859        Record.push_back(VE.getValueID(C->getOperand(1)));
860        Record.push_back(VE.getValueID(C->getOperand(2)));
861        break;
862      case Instruction::ExtractElement:
863        Code = bitc::CST_CODE_CE_EXTRACTELT;
864        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
865        Record.push_back(VE.getValueID(C->getOperand(0)));
866        Record.push_back(VE.getValueID(C->getOperand(1)));
867        break;
868      case Instruction::InsertElement:
869        Code = bitc::CST_CODE_CE_INSERTELT;
870        Record.push_back(VE.getValueID(C->getOperand(0)));
871        Record.push_back(VE.getValueID(C->getOperand(1)));
872        Record.push_back(VE.getValueID(C->getOperand(2)));
873        break;
874      case Instruction::ShuffleVector:
875        // If the return type and argument types are the same, this is a
876        // standard shufflevector instruction.  If the types are different,
877        // then the shuffle is widening or truncating the input vectors, and
878        // the argument type must also be encoded.
879        if (C->getType() == C->getOperand(0)->getType()) {
880          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
881        } else {
882          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
883          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
884        }
885        Record.push_back(VE.getValueID(C->getOperand(0)));
886        Record.push_back(VE.getValueID(C->getOperand(1)));
887        Record.push_back(VE.getValueID(C->getOperand(2)));
888        break;
889      case Instruction::ICmp:
890      case Instruction::FCmp:
891        Code = bitc::CST_CODE_CE_CMP;
892        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
893        Record.push_back(VE.getValueID(C->getOperand(0)));
894        Record.push_back(VE.getValueID(C->getOperand(1)));
895        Record.push_back(CE->getPredicate());
896        break;
897      }
898    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
899      assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
900             "Malformed blockaddress");
901      Code = bitc::CST_CODE_BLOCKADDRESS;
902      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
903      Record.push_back(VE.getValueID(BA->getFunction()));
904      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
905    } else {
906#ifndef NDEBUG
907      C->dump();
908#endif
909      llvm_unreachable("Unknown constant!");
910    }
911    Stream.EmitRecord(Code, Record, AbbrevToUse);
912    Record.clear();
913  }
914
915  Stream.ExitBlock();
916}
917
918static void WriteModuleConstants(const ValueEnumerator &VE,
919                                 BitstreamWriter &Stream) {
920  const ValueEnumerator::ValueList &Vals = VE.getValues();
921
922  // Find the first constant to emit, which is the first non-globalvalue value.
923  // We know globalvalues have been emitted by WriteModuleInfo.
924  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
925    if (!isa<GlobalValue>(Vals[i].first)) {
926      WriteConstants(i, Vals.size(), VE, Stream, true);
927      return;
928    }
929  }
930}
931
932/// PushValueAndType - The file has to encode both the value and type id for
933/// many values, because we need to know what type to create for forward
934/// references.  However, most operands are not forward references, so this type
935/// field is not needed.
936///
937/// This function adds V's value ID to Vals.  If the value ID is higher than the
938/// instruction ID, then it is a forward reference, and it also includes the
939/// type ID.
940static bool PushValueAndType(const Value *V, unsigned InstID,
941                             SmallVector<unsigned, 64> &Vals,
942                             ValueEnumerator &VE) {
943  unsigned ValID = VE.getValueID(V);
944  Vals.push_back(ValID);
945  if (ValID >= InstID) {
946    Vals.push_back(VE.getTypeID(V->getType()));
947    return true;
948  }
949  return false;
950}
951
952/// WriteInstruction - Emit an instruction to the specified stream.
953static void WriteInstruction(const Instruction &I, unsigned InstID,
954                             ValueEnumerator &VE, BitstreamWriter &Stream,
955                             SmallVector<unsigned, 64> &Vals) {
956  unsigned Code = 0;
957  unsigned AbbrevToUse = 0;
958  VE.setInstructionID(&I);
959  switch (I.getOpcode()) {
960  default:
961    if (Instruction::isCast(I.getOpcode())) {
962      Code = bitc::FUNC_CODE_INST_CAST;
963      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
964        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
965      Vals.push_back(VE.getTypeID(I.getType()));
966      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
967    } else {
968      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
969      Code = bitc::FUNC_CODE_INST_BINOP;
970      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
971        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
972      Vals.push_back(VE.getValueID(I.getOperand(1)));
973      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
974      uint64_t Flags = GetOptimizationFlags(&I);
975      if (Flags != 0) {
976        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
977          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
978        Vals.push_back(Flags);
979      }
980    }
981    break;
982
983  case Instruction::GetElementPtr:
984    Code = bitc::FUNC_CODE_INST_GEP;
985    if (cast<GEPOperator>(&I)->isInBounds())
986      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
987    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
988      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
989    break;
990  case Instruction::ExtractValue: {
991    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
992    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
993    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
994    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
995      Vals.push_back(*i);
996    break;
997  }
998  case Instruction::InsertValue: {
999    Code = bitc::FUNC_CODE_INST_INSERTVAL;
1000    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1001    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1002    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1003    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1004      Vals.push_back(*i);
1005    break;
1006  }
1007  case Instruction::Select:
1008    Code = bitc::FUNC_CODE_INST_VSELECT;
1009    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1010    Vals.push_back(VE.getValueID(I.getOperand(2)));
1011    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1012    break;
1013  case Instruction::ExtractElement:
1014    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1015    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1016    Vals.push_back(VE.getValueID(I.getOperand(1)));
1017    break;
1018  case Instruction::InsertElement:
1019    Code = bitc::FUNC_CODE_INST_INSERTELT;
1020    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1021    Vals.push_back(VE.getValueID(I.getOperand(1)));
1022    Vals.push_back(VE.getValueID(I.getOperand(2)));
1023    break;
1024  case Instruction::ShuffleVector:
1025    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1026    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1027    Vals.push_back(VE.getValueID(I.getOperand(1)));
1028    Vals.push_back(VE.getValueID(I.getOperand(2)));
1029    break;
1030  case Instruction::ICmp:
1031  case Instruction::FCmp:
1032    // compare returning Int1Ty or vector of Int1Ty
1033    Code = bitc::FUNC_CODE_INST_CMP2;
1034    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1035    Vals.push_back(VE.getValueID(I.getOperand(1)));
1036    Vals.push_back(cast<CmpInst>(I).getPredicate());
1037    break;
1038
1039  case Instruction::Ret:
1040    {
1041      Code = bitc::FUNC_CODE_INST_RET;
1042      unsigned NumOperands = I.getNumOperands();
1043      if (NumOperands == 0)
1044        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1045      else if (NumOperands == 1) {
1046        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1047          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1048      } else {
1049        for (unsigned i = 0, e = NumOperands; i != e; ++i)
1050          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1051      }
1052    }
1053    break;
1054  case Instruction::Br:
1055    {
1056      Code = bitc::FUNC_CODE_INST_BR;
1057      BranchInst &II = cast<BranchInst>(I);
1058      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1059      if (II.isConditional()) {
1060        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1061        Vals.push_back(VE.getValueID(II.getCondition()));
1062      }
1063    }
1064    break;
1065  case Instruction::Switch:
1066    Code = bitc::FUNC_CODE_INST_SWITCH;
1067    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1068    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1069      Vals.push_back(VE.getValueID(I.getOperand(i)));
1070    break;
1071  case Instruction::IndirectBr:
1072    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1073    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1074    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1075      Vals.push_back(VE.getValueID(I.getOperand(i)));
1076    break;
1077
1078  case Instruction::Invoke: {
1079    const InvokeInst *II = cast<InvokeInst>(&I);
1080    const Value *Callee(II->getCalledValue());
1081    const PointerType *PTy = cast<PointerType>(Callee->getType());
1082    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1083    Code = bitc::FUNC_CODE_INST_INVOKE;
1084
1085    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1086    Vals.push_back(II->getCallingConv());
1087    Vals.push_back(VE.getValueID(II->getNormalDest()));
1088    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1089    PushValueAndType(Callee, InstID, Vals, VE);
1090
1091    // Emit value #'s for the fixed parameters.
1092    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1093      Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1094
1095    // Emit type/value pairs for varargs params.
1096    if (FTy->isVarArg()) {
1097      for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1098           i != e; ++i)
1099        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1100    }
1101    break;
1102  }
1103  case Instruction::Unwind:
1104    Code = bitc::FUNC_CODE_INST_UNWIND;
1105    break;
1106  case Instruction::Unreachable:
1107    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1108    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1109    break;
1110
1111  case Instruction::PHI:
1112    Code = bitc::FUNC_CODE_INST_PHI;
1113    Vals.push_back(VE.getTypeID(I.getType()));
1114    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1115      Vals.push_back(VE.getValueID(I.getOperand(i)));
1116    break;
1117
1118  case Instruction::Alloca:
1119    Code = bitc::FUNC_CODE_INST_ALLOCA;
1120    Vals.push_back(VE.getTypeID(I.getType()));
1121    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1122    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1123    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1124    break;
1125
1126  case Instruction::Load:
1127    Code = bitc::FUNC_CODE_INST_LOAD;
1128    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1129      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1130
1131    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1132    Vals.push_back(cast<LoadInst>(I).isVolatile());
1133    break;
1134  case Instruction::Store:
1135    Code = bitc::FUNC_CODE_INST_STORE2;
1136    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1137    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1138    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1139    Vals.push_back(cast<StoreInst>(I).isVolatile());
1140    break;
1141  case Instruction::Call: {
1142    const CallInst &CI = cast<CallInst>(I);
1143    const PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1144    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1145
1146    Code = bitc::FUNC_CODE_INST_CALL;
1147
1148    Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1149    Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1150    PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1151
1152    // Emit value #'s for the fixed parameters.
1153    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1154      Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1155
1156    // Emit type/value pairs for varargs params.
1157    if (FTy->isVarArg()) {
1158      for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1159           i != e; ++i)
1160        PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1161    }
1162    break;
1163  }
1164  case Instruction::VAArg:
1165    Code = bitc::FUNC_CODE_INST_VAARG;
1166    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1167    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1168    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1169    break;
1170  }
1171
1172  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1173  Vals.clear();
1174}
1175
1176// Emit names for globals/functions etc.
1177static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1178                                  const ValueEnumerator &VE,
1179                                  BitstreamWriter &Stream) {
1180  if (VST.empty()) return;
1181  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1182
1183  // FIXME: Set up the abbrev, we know how many values there are!
1184  // FIXME: We know if the type names can use 7-bit ascii.
1185  SmallVector<unsigned, 64> NameVals;
1186
1187  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1188       SI != SE; ++SI) {
1189
1190    const ValueName &Name = *SI;
1191
1192    // Figure out the encoding to use for the name.
1193    bool is7Bit = true;
1194    bool isChar6 = true;
1195    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1196         C != E; ++C) {
1197      if (isChar6)
1198        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1199      if ((unsigned char)*C & 128) {
1200        is7Bit = false;
1201        break;  // don't bother scanning the rest.
1202      }
1203    }
1204
1205    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1206
1207    // VST_ENTRY:   [valueid, namechar x N]
1208    // VST_BBENTRY: [bbid, namechar x N]
1209    unsigned Code;
1210    if (isa<BasicBlock>(SI->getValue())) {
1211      Code = bitc::VST_CODE_BBENTRY;
1212      if (isChar6)
1213        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1214    } else {
1215      Code = bitc::VST_CODE_ENTRY;
1216      if (isChar6)
1217        AbbrevToUse = VST_ENTRY_6_ABBREV;
1218      else if (is7Bit)
1219        AbbrevToUse = VST_ENTRY_7_ABBREV;
1220    }
1221
1222    NameVals.push_back(VE.getValueID(SI->getValue()));
1223    for (const char *P = Name.getKeyData(),
1224         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1225      NameVals.push_back((unsigned char)*P);
1226
1227    // Emit the finished record.
1228    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1229    NameVals.clear();
1230  }
1231  Stream.ExitBlock();
1232}
1233
1234/// WriteFunction - Emit a function body to the module stream.
1235static void WriteFunction(const Function &F, ValueEnumerator &VE,
1236                          BitstreamWriter &Stream) {
1237  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1238  VE.incorporateFunction(F);
1239
1240  SmallVector<unsigned, 64> Vals;
1241
1242  // Emit the number of basic blocks, so the reader can create them ahead of
1243  // time.
1244  Vals.push_back(VE.getBasicBlocks().size());
1245  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1246  Vals.clear();
1247
1248  // If there are function-local constants, emit them now.
1249  unsigned CstStart, CstEnd;
1250  VE.getFunctionConstantRange(CstStart, CstEnd);
1251  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1252
1253  // If there is function-local metadata, emit it now.
1254  WriteFunctionLocalMetadata(F, VE, Stream);
1255
1256  // Keep a running idea of what the instruction ID is.
1257  unsigned InstID = CstEnd;
1258
1259  bool NeedsMetadataAttachment = false;
1260
1261  DebugLoc LastDL;
1262
1263  // Finally, emit all the instructions, in order.
1264  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1265    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1266         I != E; ++I) {
1267      WriteInstruction(*I, InstID, VE, Stream, Vals);
1268
1269      if (!I->getType()->isVoidTy())
1270        ++InstID;
1271
1272      // If the instruction has metadata, write a metadata attachment later.
1273      NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1274
1275      // If the instruction has a debug location, emit it.
1276      DebugLoc DL = I->getDebugLoc();
1277      if (DL.isUnknown()) {
1278        // nothing todo.
1279      } else if (DL == LastDL) {
1280        // Just repeat the same debug loc as last time.
1281        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1282      } else {
1283        MDNode *Scope, *IA;
1284        DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1285
1286        Vals.push_back(DL.getLine());
1287        Vals.push_back(DL.getCol());
1288        Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1289        Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1290        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1291        Vals.clear();
1292
1293        LastDL = DL;
1294      }
1295    }
1296
1297  // Emit names for all the instructions etc.
1298  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1299
1300  if (NeedsMetadataAttachment)
1301    WriteMetadataAttachment(F, VE, Stream);
1302  VE.purgeFunction();
1303  Stream.ExitBlock();
1304}
1305
1306/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1307static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1308                                 const ValueEnumerator &VE,
1309                                 BitstreamWriter &Stream) {
1310  if (TST.empty()) return;
1311
1312  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1313
1314  // 7-bit fixed width VST_CODE_ENTRY strings.
1315  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1316  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1317  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1318                            Log2_32_Ceil(VE.getTypes().size()+1)));
1319  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1320  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1321  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1322
1323  SmallVector<unsigned, 64> NameVals;
1324
1325  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1326       TI != TE; ++TI) {
1327    // TST_ENTRY: [typeid, namechar x N]
1328    NameVals.push_back(VE.getTypeID(TI->second));
1329
1330    const std::string &Str = TI->first;
1331    bool is7Bit = true;
1332    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1333      NameVals.push_back((unsigned char)Str[i]);
1334      if (Str[i] & 128)
1335        is7Bit = false;
1336    }
1337
1338    // Emit the finished record.
1339    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1340    NameVals.clear();
1341  }
1342
1343  Stream.ExitBlock();
1344}
1345
1346// Emit blockinfo, which defines the standard abbreviations etc.
1347static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1348  // We only want to emit block info records for blocks that have multiple
1349  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1350  // blocks can defined their abbrevs inline.
1351  Stream.EnterBlockInfoBlock(2);
1352
1353  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1354    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1355    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1356    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1357    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1358    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1359    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1360                                   Abbv) != VST_ENTRY_8_ABBREV)
1361      llvm_unreachable("Unexpected abbrev ordering!");
1362  }
1363
1364  { // 7-bit fixed width VST_ENTRY strings.
1365    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1366    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1367    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1368    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1369    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1370    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1371                                   Abbv) != VST_ENTRY_7_ABBREV)
1372      llvm_unreachable("Unexpected abbrev ordering!");
1373  }
1374  { // 6-bit char6 VST_ENTRY strings.
1375    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1376    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1377    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1379    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1380    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1381                                   Abbv) != VST_ENTRY_6_ABBREV)
1382      llvm_unreachable("Unexpected abbrev ordering!");
1383  }
1384  { // 6-bit char6 VST_BBENTRY strings.
1385    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1386    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1387    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1388    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1389    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1390    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1391                                   Abbv) != VST_BBENTRY_6_ABBREV)
1392      llvm_unreachable("Unexpected abbrev ordering!");
1393  }
1394
1395
1396
1397  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1398    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1399    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1400    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1401                              Log2_32_Ceil(VE.getTypes().size()+1)));
1402    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1403                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1404      llvm_unreachable("Unexpected abbrev ordering!");
1405  }
1406
1407  { // INTEGER abbrev for CONSTANTS_BLOCK.
1408    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1409    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1410    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1411    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1412                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1413      llvm_unreachable("Unexpected abbrev ordering!");
1414  }
1415
1416  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1417    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1418    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1419    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1420    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1421                              Log2_32_Ceil(VE.getTypes().size()+1)));
1422    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1423
1424    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1425                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1426      llvm_unreachable("Unexpected abbrev ordering!");
1427  }
1428  { // NULL abbrev for CONSTANTS_BLOCK.
1429    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1430    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1431    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1432                                   Abbv) != CONSTANTS_NULL_Abbrev)
1433      llvm_unreachable("Unexpected abbrev ordering!");
1434  }
1435
1436  // FIXME: This should only use space for first class types!
1437
1438  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1439    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1440    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1441    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1442    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1443    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1444    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1445                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1446      llvm_unreachable("Unexpected abbrev ordering!");
1447  }
1448  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1449    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1450    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1451    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1452    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1453    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1454    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1455                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1456      llvm_unreachable("Unexpected abbrev ordering!");
1457  }
1458  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1459    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1460    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1461    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1462    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1463    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1464    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1465    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1466                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1467      llvm_unreachable("Unexpected abbrev ordering!");
1468  }
1469  { // INST_CAST abbrev for FUNCTION_BLOCK.
1470    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1471    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1472    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1473    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1474                              Log2_32_Ceil(VE.getTypes().size()+1)));
1475    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1476    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1477                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1478      llvm_unreachable("Unexpected abbrev ordering!");
1479  }
1480
1481  { // INST_RET abbrev for FUNCTION_BLOCK.
1482    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1483    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1484    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1485                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1486      llvm_unreachable("Unexpected abbrev ordering!");
1487  }
1488  { // INST_RET abbrev for FUNCTION_BLOCK.
1489    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1490    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1491    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1492    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1493                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1494      llvm_unreachable("Unexpected abbrev ordering!");
1495  }
1496  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1497    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1498    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1499    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1500                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1501      llvm_unreachable("Unexpected abbrev ordering!");
1502  }
1503
1504  Stream.ExitBlock();
1505}
1506
1507
1508/// WriteModule - Emit the specified module to the bitstream.
1509static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1510  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1511
1512  // Emit the version number if it is non-zero.
1513  if (CurVersion) {
1514    SmallVector<unsigned, 1> Vals;
1515    Vals.push_back(CurVersion);
1516    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1517  }
1518
1519  // Analyze the module, enumerating globals, functions, etc.
1520  ValueEnumerator VE(M);
1521
1522  // Emit blockinfo, which defines the standard abbreviations etc.
1523  WriteBlockInfo(VE, Stream);
1524
1525  // Emit information about parameter attributes.
1526  WriteAttributeTable(VE, Stream);
1527
1528  // Emit information describing all of the types in the module.
1529  WriteTypeTable(VE, Stream);
1530
1531  // Emit top-level description of module, including target triple, inline asm,
1532  // descriptors for global variables, and function prototype info.
1533  WriteModuleInfo(M, VE, Stream);
1534
1535  // Emit constants.
1536  WriteModuleConstants(VE, Stream);
1537
1538  // Emit metadata.
1539  WriteModuleMetadata(M, VE, Stream);
1540
1541  // Emit function bodies.
1542  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1543    if (!I->isDeclaration())
1544      WriteFunction(*I, VE, Stream);
1545
1546  // Emit metadata.
1547  WriteModuleMetadataStore(M, Stream);
1548
1549  // Emit the type symbol table information.
1550  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1551
1552  // Emit names for globals/functions etc.
1553  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1554
1555  Stream.ExitBlock();
1556}
1557
1558/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1559/// header and trailer to make it compatible with the system archiver.  To do
1560/// this we emit the following header, and then emit a trailer that pads the
1561/// file out to be a multiple of 16 bytes.
1562///
1563/// struct bc_header {
1564///   uint32_t Magic;         // 0x0B17C0DE
1565///   uint32_t Version;       // Version, currently always 0.
1566///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1567///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1568///   uint32_t CPUType;       // CPU specifier.
1569///   ... potentially more later ...
1570/// };
1571enum {
1572  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1573  DarwinBCHeaderSize = 5*4
1574};
1575
1576/// isARMTriplet - Return true if the triplet looks like:
1577/// arm-*, thumb-*, armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*.
1578static bool isARMTriplet(const std::string &TT) {
1579  size_t Pos = 0;
1580  size_t Size = TT.size();
1581  if (Size >= 6 &&
1582      TT[0] == 't' && TT[1] == 'h' && TT[2] == 'u' &&
1583      TT[3] == 'm' && TT[4] == 'b')
1584    Pos = 5;
1585  else if (Size >= 4 && TT[0] == 'a' && TT[1] == 'r' && TT[2] == 'm')
1586    Pos = 3;
1587  else
1588    return false;
1589
1590  if (TT[Pos] == '-')
1591    return true;
1592  else if (TT[Pos] == 'v') {
1593    if (Size >= Pos+4 &&
1594        TT[Pos+1] == '6' && TT[Pos+2] == 't' && TT[Pos+3] == '2')
1595      return true;
1596    else if (Size >= Pos+4 &&
1597             TT[Pos+1] == '5' && TT[Pos+2] == 't' && TT[Pos+3] == 'e')
1598      return true;
1599  } else
1600    return false;
1601  while (++Pos < Size && TT[Pos] != '-') {
1602    if (!isdigit(TT[Pos]))
1603      return false;
1604  }
1605  return true;
1606}
1607
1608static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1609                               const std::string &TT) {
1610  unsigned CPUType = ~0U;
1611
1612  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1613  // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1614  // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1615  // specific constants here because they are implicitly part of the Darwin ABI.
1616  enum {
1617    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1618    DARWIN_CPU_TYPE_X86        = 7,
1619    DARWIN_CPU_TYPE_ARM        = 12,
1620    DARWIN_CPU_TYPE_POWERPC    = 18
1621  };
1622
1623  if (TT.find("x86_64-") == 0)
1624    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1625  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1626           TT[4] == '-' && TT[1] - '3' < 6)
1627    CPUType = DARWIN_CPU_TYPE_X86;
1628  else if (TT.find("powerpc-") == 0)
1629    CPUType = DARWIN_CPU_TYPE_POWERPC;
1630  else if (TT.find("powerpc64-") == 0)
1631    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1632  else if (isARMTriplet(TT))
1633    CPUType = DARWIN_CPU_TYPE_ARM;
1634
1635  // Traditional Bitcode starts after header.
1636  unsigned BCOffset = DarwinBCHeaderSize;
1637
1638  Stream.Emit(0x0B17C0DE, 32);
1639  Stream.Emit(0         , 32);  // Version.
1640  Stream.Emit(BCOffset  , 32);
1641  Stream.Emit(0         , 32);  // Filled in later.
1642  Stream.Emit(CPUType   , 32);
1643}
1644
1645/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1646/// finalize the header.
1647static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1648  // Update the size field in the header.
1649  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1650
1651  // If the file is not a multiple of 16 bytes, insert dummy padding.
1652  while (BufferSize & 15) {
1653    Stream.Emit(0, 8);
1654    ++BufferSize;
1655  }
1656}
1657
1658
1659/// WriteBitcodeToFile - Write the specified module to the specified output
1660/// stream.
1661void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1662  std::vector<unsigned char> Buffer;
1663  BitstreamWriter Stream(Buffer);
1664
1665  Buffer.reserve(256*1024);
1666
1667  WriteBitcodeToStream( M, Stream );
1668
1669  // Write the generated bitstream to "Out".
1670  Out.write((char*)&Buffer.front(), Buffer.size());
1671}
1672
1673/// WriteBitcodeToStream - Write the specified module to the specified output
1674/// stream.
1675void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1676  // If this is darwin, emit a file header and trailer if needed.
1677  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1678  if (isDarwin)
1679    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1680
1681  // Emit the file header.
1682  Stream.Emit((unsigned)'B', 8);
1683  Stream.Emit((unsigned)'C', 8);
1684  Stream.Emit(0x0, 4);
1685  Stream.Emit(0xC, 4);
1686  Stream.Emit(0xE, 4);
1687  Stream.Emit(0xD, 4);
1688
1689  // Emit the module.
1690  WriteModule(M, Stream);
1691
1692  if (isDarwin)
1693    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1694}
1695