BitcodeWriter.cpp revision d701aa7bed07cad16e33594c59251c958df2c74d 
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
476/// WriteValues - Write Constants and Metadata.
477/// This function could use some refactoring help.
478static void WriteValues(unsigned FirstVal, unsigned LastVal,
479                        const ValueEnumerator &VE,
480                        BitstreamWriter &Stream, bool isGlobal) {
481  if (FirstVal == LastVal) return;
482
483  // MODULE_BLOCK_ID is 0, which is not handled here. So it is OK to use
484  // 0 as the initializer to indicate that block is not set.
485  enum bitc::BlockIDs LastBlockID = bitc::MODULE_BLOCK_ID;
486
487  unsigned AggregateAbbrev = 0;
488  unsigned String8Abbrev = 0;
489  unsigned CString7Abbrev = 0;
490  unsigned CString6Abbrev = 0;
491  unsigned MDSAbbrev = 0;
492
493  SmallVector<uint64_t, 64> Record;
494
495  const ValueEnumerator::ValueList &Vals = VE.getValues();
496  const Type *LastTy = 0;
497  for (unsigned i = FirstVal; i != LastVal; ++i) {
498    const Value *V = Vals[i].first;
499    if (isa<MetadataBase>(V)) {
500      if (LastBlockID != bitc::METADATA_BLOCK_ID) {
501        // Exit privious block.
502        if (LastBlockID != bitc::MODULE_BLOCK_ID)
503          Stream.ExitBlock();
504
505        LastBlockID = bitc::METADATA_BLOCK_ID;
506        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
507      }
508    }
509    if (const MDString *MDS = dyn_cast<MDString>(V)) {
510      if (MDSAbbrev == 0) {
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      }
518      // Code: [strchar x N]
519      const char *StrBegin = MDS->begin();
520      for (unsigned i = 0, e = MDS->length(); i != e; ++i)
521        Record.push_back(StrBegin[i]);
522
523      // Emit the finished record.
524      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
525      Record.clear();
526      continue;
527    } else if (const MDNode *N = dyn_cast<MDNode>(V)) {
528      for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
529        if (N->getElement(i)) {
530          Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
531          Record.push_back(VE.getValueID(N->getElement(i)));
532        } else {
533          Record.push_back(VE.getTypeID(Type::VoidTy));
534          Record.push_back(0);
535        }
536      }
537      Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
538      Record.clear();
539      continue;
540    } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(V)) {
541      // Write name.
542      std::string Str = NMD->getNameStr();
543      const char *StrBegin = Str.c_str();
544      for (unsigned i = 0, e = Str.length(); i != e; ++i)
545        Record.push_back(StrBegin[i]);
546      Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
547      Record.clear();
548
549      // Write named metadata elements.
550      for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
551        if (NMD->getElement(i))
552          Record.push_back(VE.getValueID(NMD->getElement(i)));
553        else
554          Record.push_back(0);
555      }
556      Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
557      Record.clear();
558      continue;
559    }
560
561    // If we need to switch block, do so now.
562    if (LastBlockID != bitc::CONSTANTS_BLOCK_ID) {
563      // Exit privious block.
564      if (LastBlockID != bitc::MODULE_BLOCK_ID)
565        Stream.ExitBlock();
566
567      LastBlockID = bitc::CONSTANTS_BLOCK_ID;
568      Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
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
585        // Abbrev for CST_CODE_CSTRING.
586        Abbv = new BitCodeAbbrev();
587        Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
588        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
589        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
590        CString7Abbrev = Stream.EmitAbbrev(Abbv);
591
592        // Abbrev for CST_CODE_CSTRING.
593        Abbv = new BitCodeAbbrev();
594        Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
595        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
596        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
597        CString6Abbrev = Stream.EmitAbbrev(Abbv);
598      }
599
600    }
601    if (isa<MetadataBase>(V))
602      continue;
603    // If we need to switch types, do so now.
604    if (V->getType() != LastTy) {
605      LastTy = V->getType();
606      Record.push_back(VE.getTypeID(LastTy));
607      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
608                        CONSTANTS_SETTYPE_ABBREV);
609      Record.clear();
610    }
611
612    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
613      Record.push_back(unsigned(IA->hasSideEffects()));
614
615      // Add the asm string.
616      const std::string &AsmStr = IA->getAsmString();
617      Record.push_back(AsmStr.size());
618      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
619        Record.push_back(AsmStr[i]);
620
621      // Add the constraint string.
622      const std::string &ConstraintStr = IA->getConstraintString();
623      Record.push_back(ConstraintStr.size());
624      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
625        Record.push_back(ConstraintStr[i]);
626      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
627      Record.clear();
628      continue;
629    }
630    const Constant *C = cast<Constant>(V);
631    unsigned Code = -1U;
632    unsigned AbbrevToUse = 0;
633    if (C->isNullValue()) {
634      Code = bitc::CST_CODE_NULL;
635    } else if (isa<UndefValue>(C)) {
636      Code = bitc::CST_CODE_UNDEF;
637    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
638      if (IV->getBitWidth() <= 64) {
639        int64_t V = IV->getSExtValue();
640        if (V >= 0)
641          Record.push_back(V << 1);
642        else
643          Record.push_back((-V << 1) | 1);
644        Code = bitc::CST_CODE_INTEGER;
645        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
646      } else {                             // Wide integers, > 64 bits in size.
647        // We have an arbitrary precision integer value to write whose
648        // bit width is > 64. However, in canonical unsigned integer
649        // format it is likely that the high bits are going to be zero.
650        // So, we only write the number of active words.
651        unsigned NWords = IV->getValue().getActiveWords();
652        const uint64_t *RawWords = IV->getValue().getRawData();
653        for (unsigned i = 0; i != NWords; ++i) {
654          int64_t V = RawWords[i];
655          if (V >= 0)
656            Record.push_back(V << 1);
657          else
658            Record.push_back((-V << 1) | 1);
659        }
660        Code = bitc::CST_CODE_WIDE_INTEGER;
661      }
662    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
663      Code = bitc::CST_CODE_FLOAT;
664      const Type *Ty = CFP->getType();
665      if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
666        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
667      } else if (Ty == Type::X86_FP80Ty) {
668        // api needed to prevent premature destruction
669        // bits are not in the same order as a normal i80 APInt, compensate.
670        APInt api = CFP->getValueAPF().bitcastToAPInt();
671        const uint64_t *p = api.getRawData();
672        Record.push_back((p[1] << 48) | (p[0] >> 16));
673        Record.push_back(p[0] & 0xffffLL);
674      } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
675        APInt api = CFP->getValueAPF().bitcastToAPInt();
676        const uint64_t *p = api.getRawData();
677        Record.push_back(p[0]);
678        Record.push_back(p[1]);
679      } else {
680        assert (0 && "Unknown FP type!");
681      }
682    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
683      // Emit constant strings specially.
684      unsigned NumOps = C->getNumOperands();
685      // If this is a null-terminated string, use the denser CSTRING encoding.
686      if (C->getOperand(NumOps-1)->isNullValue()) {
687        Code = bitc::CST_CODE_CSTRING;
688        --NumOps;  // Don't encode the null, which isn't allowed by char6.
689      } else {
690        Code = bitc::CST_CODE_STRING;
691        AbbrevToUse = String8Abbrev;
692      }
693      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
694      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
695      for (unsigned i = 0; i != NumOps; ++i) {
696        unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
697        Record.push_back(V);
698        isCStr7 &= (V & 128) == 0;
699        if (isCStrChar6)
700          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
701      }
702
703      if (isCStrChar6)
704        AbbrevToUse = CString6Abbrev;
705      else if (isCStr7)
706        AbbrevToUse = CString7Abbrev;
707    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
708               isa<ConstantVector>(V)) {
709      Code = bitc::CST_CODE_AGGREGATE;
710      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
711        Record.push_back(VE.getValueID(C->getOperand(i)));
712      AbbrevToUse = AggregateAbbrev;
713    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
714      switch (CE->getOpcode()) {
715      default:
716        if (Instruction::isCast(CE->getOpcode())) {
717          Code = bitc::CST_CODE_CE_CAST;
718          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
719          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
720          Record.push_back(VE.getValueID(C->getOperand(0)));
721          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
722        } else {
723          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
724          Code = bitc::CST_CODE_CE_BINOP;
725          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
726          Record.push_back(VE.getValueID(C->getOperand(0)));
727          Record.push_back(VE.getValueID(C->getOperand(1)));
728          uint64_t Flags = GetOptimizationFlags(CE);
729          if (Flags != 0)
730            Record.push_back(Flags);
731        }
732        break;
733      case Instruction::GetElementPtr:
734        Code = bitc::CST_CODE_CE_GEP;
735        if (cast<GEPOperator>(C)->isInBounds())
736          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
737        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
738          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
739          Record.push_back(VE.getValueID(C->getOperand(i)));
740        }
741        break;
742      case Instruction::Select:
743        Code = bitc::CST_CODE_CE_SELECT;
744        Record.push_back(VE.getValueID(C->getOperand(0)));
745        Record.push_back(VE.getValueID(C->getOperand(1)));
746        Record.push_back(VE.getValueID(C->getOperand(2)));
747        break;
748      case Instruction::ExtractElement:
749        Code = bitc::CST_CODE_CE_EXTRACTELT;
750        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
751        Record.push_back(VE.getValueID(C->getOperand(0)));
752        Record.push_back(VE.getValueID(C->getOperand(1)));
753        break;
754      case Instruction::InsertElement:
755        Code = bitc::CST_CODE_CE_INSERTELT;
756        Record.push_back(VE.getValueID(C->getOperand(0)));
757        Record.push_back(VE.getValueID(C->getOperand(1)));
758        Record.push_back(VE.getValueID(C->getOperand(2)));
759        break;
760      case Instruction::ShuffleVector:
761        // If the return type and argument types are the same, this is a
762        // standard shufflevector instruction.  If the types are different,
763        // then the shuffle is widening or truncating the input vectors, and
764        // the argument type must also be encoded.
765        if (C->getType() == C->getOperand(0)->getType()) {
766          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
767        } else {
768          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
769          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
770        }
771        Record.push_back(VE.getValueID(C->getOperand(0)));
772        Record.push_back(VE.getValueID(C->getOperand(1)));
773        Record.push_back(VE.getValueID(C->getOperand(2)));
774        break;
775      case Instruction::ICmp:
776      case Instruction::FCmp:
777        Code = bitc::CST_CODE_CE_CMP;
778        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
779        Record.push_back(VE.getValueID(C->getOperand(0)));
780        Record.push_back(VE.getValueID(C->getOperand(1)));
781        Record.push_back(CE->getPredicate());
782        break;
783      }
784    } else {
785      llvm_unreachable("Unknown constant!");
786    }
787    Stream.EmitRecord(Code, Record, AbbrevToUse);
788    Record.clear();
789  }
790
791  Stream.ExitBlock();
792}
793
794static void WriteModuleConstants(const ValueEnumerator &VE,
795                                 BitstreamWriter &Stream) {
796  const ValueEnumerator::ValueList &Vals = VE.getValues();
797
798  // Find the first constant to emit, which is the first non-globalvalue value.
799  // We know globalvalues have been emitted by WriteModuleInfo.
800  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
801    if (!isa<GlobalValue>(Vals[i].first)) {
802      WriteValues(i, Vals.size(), VE, Stream, true);
803      return;
804    }
805  }
806}
807
808/// PushValueAndType - The file has to encode both the value and type id for
809/// many values, because we need to know what type to create for forward
810/// references.  However, most operands are not forward references, so this type
811/// field is not needed.
812///
813/// This function adds V's value ID to Vals.  If the value ID is higher than the
814/// instruction ID, then it is a forward reference, and it also includes the
815/// type ID.
816static bool PushValueAndType(const Value *V, unsigned InstID,
817                             SmallVector<unsigned, 64> &Vals,
818                             ValueEnumerator &VE) {
819  unsigned ValID = VE.getValueID(V);
820  Vals.push_back(ValID);
821  if (ValID >= InstID) {
822    Vals.push_back(VE.getTypeID(V->getType()));
823    return true;
824  }
825  return false;
826}
827
828/// WriteInstruction - Emit an instruction to the specified stream.
829static void WriteInstruction(const Instruction &I, unsigned InstID,
830                             ValueEnumerator &VE, BitstreamWriter &Stream,
831                             SmallVector<unsigned, 64> &Vals) {
832  unsigned Code = 0;
833  unsigned AbbrevToUse = 0;
834  switch (I.getOpcode()) {
835  default:
836    if (Instruction::isCast(I.getOpcode())) {
837      Code = bitc::FUNC_CODE_INST_CAST;
838      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
839        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
840      Vals.push_back(VE.getTypeID(I.getType()));
841      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
842    } else {
843      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
844      Code = bitc::FUNC_CODE_INST_BINOP;
845      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
846        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
847      Vals.push_back(VE.getValueID(I.getOperand(1)));
848      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
849      uint64_t Flags = GetOptimizationFlags(&I);
850      if (Flags != 0) {
851        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
852          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
853        Vals.push_back(Flags);
854      }
855    }
856    break;
857
858  case Instruction::GetElementPtr:
859    Code = bitc::FUNC_CODE_INST_GEP;
860    if (cast<GEPOperator>(&I)->isInBounds())
861      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
862    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
863      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
864    break;
865  case Instruction::ExtractValue: {
866    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
867    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
868    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
869    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
870      Vals.push_back(*i);
871    break;
872  }
873  case Instruction::InsertValue: {
874    Code = bitc::FUNC_CODE_INST_INSERTVAL;
875    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
876    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
877    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
878    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
879      Vals.push_back(*i);
880    break;
881  }
882  case Instruction::Select:
883    Code = bitc::FUNC_CODE_INST_VSELECT;
884    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
885    Vals.push_back(VE.getValueID(I.getOperand(2)));
886    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
887    break;
888  case Instruction::ExtractElement:
889    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
890    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
891    Vals.push_back(VE.getValueID(I.getOperand(1)));
892    break;
893  case Instruction::InsertElement:
894    Code = bitc::FUNC_CODE_INST_INSERTELT;
895    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
896    Vals.push_back(VE.getValueID(I.getOperand(1)));
897    Vals.push_back(VE.getValueID(I.getOperand(2)));
898    break;
899  case Instruction::ShuffleVector:
900    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
901    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
902    Vals.push_back(VE.getValueID(I.getOperand(1)));
903    Vals.push_back(VE.getValueID(I.getOperand(2)));
904    break;
905  case Instruction::ICmp:
906  case Instruction::FCmp:
907    // compare returning Int1Ty or vector of Int1Ty
908    Code = bitc::FUNC_CODE_INST_CMP2;
909    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
910    Vals.push_back(VE.getValueID(I.getOperand(1)));
911    Vals.push_back(cast<CmpInst>(I).getPredicate());
912    break;
913
914  case Instruction::Ret:
915    {
916      Code = bitc::FUNC_CODE_INST_RET;
917      unsigned NumOperands = I.getNumOperands();
918      if (NumOperands == 0)
919        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
920      else if (NumOperands == 1) {
921        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
922          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
923      } else {
924        for (unsigned i = 0, e = NumOperands; i != e; ++i)
925          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
926      }
927    }
928    break;
929  case Instruction::Br:
930    {
931      Code = bitc::FUNC_CODE_INST_BR;
932      BranchInst &II(cast<BranchInst>(I));
933      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
934      if (II.isConditional()) {
935        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
936        Vals.push_back(VE.getValueID(II.getCondition()));
937      }
938    }
939    break;
940  case Instruction::Switch:
941    Code = bitc::FUNC_CODE_INST_SWITCH;
942    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
943    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
944      Vals.push_back(VE.getValueID(I.getOperand(i)));
945    break;
946  case Instruction::Invoke: {
947    const InvokeInst *II = cast<InvokeInst>(&I);
948    const Value *Callee(II->getCalledValue());
949    const PointerType *PTy = cast<PointerType>(Callee->getType());
950    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
951    Code = bitc::FUNC_CODE_INST_INVOKE;
952
953    Vals.push_back(VE.getAttributeID(II->getAttributes()));
954    Vals.push_back(II->getCallingConv());
955    Vals.push_back(VE.getValueID(II->getNormalDest()));
956    Vals.push_back(VE.getValueID(II->getUnwindDest()));
957    PushValueAndType(Callee, InstID, Vals, VE);
958
959    // Emit value #'s for the fixed parameters.
960    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
961      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
962
963    // Emit type/value pairs for varargs params.
964    if (FTy->isVarArg()) {
965      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
966           i != e; ++i)
967        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
968    }
969    break;
970  }
971  case Instruction::Unwind:
972    Code = bitc::FUNC_CODE_INST_UNWIND;
973    break;
974  case Instruction::Unreachable:
975    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
976    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
977    break;
978
979  case Instruction::PHI:
980    Code = bitc::FUNC_CODE_INST_PHI;
981    Vals.push_back(VE.getTypeID(I.getType()));
982    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
983      Vals.push_back(VE.getValueID(I.getOperand(i)));
984    break;
985
986  case Instruction::Malloc:
987    Code = bitc::FUNC_CODE_INST_MALLOC;
988    Vals.push_back(VE.getTypeID(I.getType()));
989    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
990    Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
991    break;
992
993  case Instruction::Free:
994    Code = bitc::FUNC_CODE_INST_FREE;
995    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
996    break;
997
998  case Instruction::Alloca:
999    Code = bitc::FUNC_CODE_INST_ALLOCA;
1000    Vals.push_back(VE.getTypeID(I.getType()));
1001    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1002    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1003    break;
1004
1005  case Instruction::Load:
1006    Code = bitc::FUNC_CODE_INST_LOAD;
1007    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1008      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1009
1010    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1011    Vals.push_back(cast<LoadInst>(I).isVolatile());
1012    break;
1013  case Instruction::Store:
1014    Code = bitc::FUNC_CODE_INST_STORE2;
1015    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1016    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1017    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1018    Vals.push_back(cast<StoreInst>(I).isVolatile());
1019    break;
1020  case Instruction::Call: {
1021    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1022    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1023
1024    Code = bitc::FUNC_CODE_INST_CALL;
1025
1026    const CallInst *CI = cast<CallInst>(&I);
1027    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1028    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1029    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1030
1031    // Emit value #'s for the fixed parameters.
1032    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1033      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1034
1035    // Emit type/value pairs for varargs params.
1036    if (FTy->isVarArg()) {
1037      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1038      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1039           i != e; ++i)
1040        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1041    }
1042    break;
1043  }
1044  case Instruction::VAArg:
1045    Code = bitc::FUNC_CODE_INST_VAARG;
1046    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1047    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1048    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1049    break;
1050  }
1051
1052  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1053  Vals.clear();
1054}
1055
1056// Emit names for globals/functions etc.
1057static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1058                                  const ValueEnumerator &VE,
1059                                  BitstreamWriter &Stream) {
1060  if (VST.empty()) return;
1061  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1062
1063  // FIXME: Set up the abbrev, we know how many values there are!
1064  // FIXME: We know if the type names can use 7-bit ascii.
1065  SmallVector<unsigned, 64> NameVals;
1066
1067  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1068       SI != SE; ++SI) {
1069
1070    const ValueName &Name = *SI;
1071
1072    // Figure out the encoding to use for the name.
1073    bool is7Bit = true;
1074    bool isChar6 = true;
1075    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1076         C != E; ++C) {
1077      if (isChar6)
1078        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1079      if ((unsigned char)*C & 128) {
1080        is7Bit = false;
1081        break;  // don't bother scanning the rest.
1082      }
1083    }
1084
1085    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1086
1087    // VST_ENTRY:   [valueid, namechar x N]
1088    // VST_BBENTRY: [bbid, namechar x N]
1089    unsigned Code;
1090    if (isa<BasicBlock>(SI->getValue())) {
1091      Code = bitc::VST_CODE_BBENTRY;
1092      if (isChar6)
1093        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1094    } else {
1095      Code = bitc::VST_CODE_ENTRY;
1096      if (isChar6)
1097        AbbrevToUse = VST_ENTRY_6_ABBREV;
1098      else if (is7Bit)
1099        AbbrevToUse = VST_ENTRY_7_ABBREV;
1100    }
1101
1102    NameVals.push_back(VE.getValueID(SI->getValue()));
1103    for (const char *P = Name.getKeyData(),
1104         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1105      NameVals.push_back((unsigned char)*P);
1106
1107    // Emit the finished record.
1108    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1109    NameVals.clear();
1110  }
1111  Stream.ExitBlock();
1112}
1113
1114/// WriteFunction - Emit a function body to the module stream.
1115static void WriteFunction(const Function &F, ValueEnumerator &VE,
1116                          BitstreamWriter &Stream) {
1117  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1118  VE.incorporateFunction(F);
1119
1120  SmallVector<unsigned, 64> Vals;
1121
1122  // Emit the number of basic blocks, so the reader can create them ahead of
1123  // time.
1124  Vals.push_back(VE.getBasicBlocks().size());
1125  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1126  Vals.clear();
1127
1128  // If there are function-local constants, emit them now.
1129  unsigned CstStart, CstEnd;
1130  VE.getFunctionConstantRange(CstStart, CstEnd);
1131  WriteValues(CstStart, CstEnd, VE, Stream, false);
1132
1133  // Keep a running idea of what the instruction ID is.
1134  unsigned InstID = CstEnd;
1135
1136  // Finally, emit all the instructions, in order.
1137  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1138    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1139         I != E; ++I) {
1140      WriteInstruction(*I, InstID, VE, Stream, Vals);
1141      if (I->getType() != Type::VoidTy)
1142        ++InstID;
1143    }
1144
1145  // Emit names for all the instructions etc.
1146  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1147
1148  VE.purgeFunction();
1149  Stream.ExitBlock();
1150}
1151
1152/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1153static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1154                                 const ValueEnumerator &VE,
1155                                 BitstreamWriter &Stream) {
1156  if (TST.empty()) return;
1157
1158  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1159
1160  // 7-bit fixed width VST_CODE_ENTRY strings.
1161  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1162  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1163  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1164                            Log2_32_Ceil(VE.getTypes().size()+1)));
1165  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1166  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1167  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1168
1169  SmallVector<unsigned, 64> NameVals;
1170
1171  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1172       TI != TE; ++TI) {
1173    // TST_ENTRY: [typeid, namechar x N]
1174    NameVals.push_back(VE.getTypeID(TI->second));
1175
1176    const std::string &Str = TI->first;
1177    bool is7Bit = true;
1178    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1179      NameVals.push_back((unsigned char)Str[i]);
1180      if (Str[i] & 128)
1181        is7Bit = false;
1182    }
1183
1184    // Emit the finished record.
1185    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1186    NameVals.clear();
1187  }
1188
1189  Stream.ExitBlock();
1190}
1191
1192// Emit blockinfo, which defines the standard abbreviations etc.
1193static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1194  // We only want to emit block info records for blocks that have multiple
1195  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1196  // blocks can defined their abbrevs inline.
1197  Stream.EnterBlockInfoBlock(2);
1198
1199  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1200    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1201    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1202    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1203    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1204    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1205    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1206                                   Abbv) != VST_ENTRY_8_ABBREV)
1207      llvm_unreachable("Unexpected abbrev ordering!");
1208  }
1209
1210  { // 7-bit fixed width VST_ENTRY strings.
1211    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1212    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1213    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1214    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1215    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1216    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1217                                   Abbv) != VST_ENTRY_7_ABBREV)
1218      llvm_unreachable("Unexpected abbrev ordering!");
1219  }
1220  { // 6-bit char6 VST_ENTRY strings.
1221    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1222    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1223    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1224    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1225    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1226    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1227                                   Abbv) != VST_ENTRY_6_ABBREV)
1228      llvm_unreachable("Unexpected abbrev ordering!");
1229  }
1230  { // 6-bit char6 VST_BBENTRY strings.
1231    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1232    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1233    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1234    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1235    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1236    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1237                                   Abbv) != VST_BBENTRY_6_ABBREV)
1238      llvm_unreachable("Unexpected abbrev ordering!");
1239  }
1240
1241
1242
1243  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1244    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1245    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1246    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1247                              Log2_32_Ceil(VE.getTypes().size()+1)));
1248    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1249                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1250      llvm_unreachable("Unexpected abbrev ordering!");
1251  }
1252
1253  { // INTEGER abbrev for CONSTANTS_BLOCK.
1254    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1255    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1256    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1257    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1258                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1259      llvm_unreachable("Unexpected abbrev ordering!");
1260  }
1261
1262  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1263    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1264    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1265    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1266    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1267                              Log2_32_Ceil(VE.getTypes().size()+1)));
1268    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1269
1270    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1271                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1272      llvm_unreachable("Unexpected abbrev ordering!");
1273  }
1274  { // NULL abbrev for CONSTANTS_BLOCK.
1275    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1276    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1277    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1278                                   Abbv) != CONSTANTS_NULL_Abbrev)
1279      llvm_unreachable("Unexpected abbrev ordering!");
1280  }
1281
1282  // FIXME: This should only use space for first class types!
1283
1284  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1285    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1286    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1287    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1288    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1289    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1290    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1291                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1292      llvm_unreachable("Unexpected abbrev ordering!");
1293  }
1294  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1295    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1296    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1297    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1298    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1299    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1300    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1301                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1302      llvm_unreachable("Unexpected abbrev ordering!");
1303  }
1304  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1305    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1306    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1307    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1308    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1309    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1310    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1311    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1312                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1313      llvm_unreachable("Unexpected abbrev ordering!");
1314  }
1315  { // INST_CAST abbrev for FUNCTION_BLOCK.
1316    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1317    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1318    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1319    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1320                              Log2_32_Ceil(VE.getTypes().size()+1)));
1321    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1322    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1323                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1324      llvm_unreachable("Unexpected abbrev ordering!");
1325  }
1326
1327  { // INST_RET abbrev for FUNCTION_BLOCK.
1328    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1329    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1330    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1331                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1332      llvm_unreachable("Unexpected abbrev ordering!");
1333  }
1334  { // INST_RET abbrev for FUNCTION_BLOCK.
1335    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1336    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1337    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1338    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1339                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1340      llvm_unreachable("Unexpected abbrev ordering!");
1341  }
1342  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1343    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1344    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1345    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1346                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1347      llvm_unreachable("Unexpected abbrev ordering!");
1348  }
1349
1350  Stream.ExitBlock();
1351}
1352
1353
1354/// WriteModule - Emit the specified module to the bitstream.
1355static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1356  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1357
1358  // Emit the version number if it is non-zero.
1359  if (CurVersion) {
1360    SmallVector<unsigned, 1> Vals;
1361    Vals.push_back(CurVersion);
1362    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1363  }
1364
1365  // Analyze the module, enumerating globals, functions, etc.
1366  ValueEnumerator VE(M);
1367
1368  // Emit blockinfo, which defines the standard abbreviations etc.
1369  WriteBlockInfo(VE, Stream);
1370
1371  // Emit information about parameter attributes.
1372  WriteAttributeTable(VE, Stream);
1373
1374  // Emit information describing all of the types in the module.
1375  WriteTypeTable(VE, Stream);
1376
1377  // Emit top-level description of module, including target triple, inline asm,
1378  // descriptors for global variables, and function prototype info.
1379  WriteModuleInfo(M, VE, Stream);
1380
1381  // Emit constants.
1382  WriteModuleConstants(VE, Stream);
1383
1384  // Emit function bodies.
1385  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1386    if (!I->isDeclaration())
1387      WriteFunction(*I, VE, Stream);
1388
1389  // Emit the type symbol table information.
1390  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1391
1392  // Emit names for globals/functions etc.
1393  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1394
1395  Stream.ExitBlock();
1396}
1397
1398/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1399/// header and trailer to make it compatible with the system archiver.  To do
1400/// this we emit the following header, and then emit a trailer that pads the
1401/// file out to be a multiple of 16 bytes.
1402///
1403/// struct bc_header {
1404///   uint32_t Magic;         // 0x0B17C0DE
1405///   uint32_t Version;       // Version, currently always 0.
1406///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1407///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1408///   uint32_t CPUType;       // CPU specifier.
1409///   ... potentially more later ...
1410/// };
1411enum {
1412  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1413  DarwinBCHeaderSize = 5*4
1414};
1415
1416static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1417                               const std::string &TT) {
1418  unsigned CPUType = ~0U;
1419
1420  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1421  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1422  // specific constants here because they are implicitly part of the Darwin ABI.
1423  enum {
1424    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1425    DARWIN_CPU_TYPE_X86        = 7,
1426    DARWIN_CPU_TYPE_POWERPC    = 18
1427  };
1428
1429  if (TT.find("x86_64-") == 0)
1430    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1431  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1432           TT[4] == '-' && TT[1] - '3' < 6)
1433    CPUType = DARWIN_CPU_TYPE_X86;
1434  else if (TT.find("powerpc-") == 0)
1435    CPUType = DARWIN_CPU_TYPE_POWERPC;
1436  else if (TT.find("powerpc64-") == 0)
1437    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1438
1439  // Traditional Bitcode starts after header.
1440  unsigned BCOffset = DarwinBCHeaderSize;
1441
1442  Stream.Emit(0x0B17C0DE, 32);
1443  Stream.Emit(0         , 32);  // Version.
1444  Stream.Emit(BCOffset  , 32);
1445  Stream.Emit(0         , 32);  // Filled in later.
1446  Stream.Emit(CPUType   , 32);
1447}
1448
1449/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1450/// finalize the header.
1451static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1452  // Update the size field in the header.
1453  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1454
1455  // If the file is not a multiple of 16 bytes, insert dummy padding.
1456  while (BufferSize & 15) {
1457    Stream.Emit(0, 8);
1458    ++BufferSize;
1459  }
1460}
1461
1462
1463/// WriteBitcodeToFile - Write the specified module to the specified output
1464/// stream.
1465void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1466  raw_os_ostream RawOut(Out);
1467  // If writing to stdout, set binary mode.
1468  if (llvm::cout == Out)
1469    sys::Program::ChangeStdoutToBinary();
1470  WriteBitcodeToFile(M, RawOut);
1471}
1472
1473/// WriteBitcodeToFile - Write the specified module to the specified output
1474/// stream.
1475void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1476  std::vector<unsigned char> Buffer;
1477  BitstreamWriter Stream(Buffer);
1478
1479  Buffer.reserve(256*1024);
1480
1481  WriteBitcodeToStream( M, Stream );
1482
1483  // If writing to stdout, set binary mode.
1484  if (&llvm::outs() == &Out)
1485    sys::Program::ChangeStdoutToBinary();
1486
1487  // Write the generated bitstream to "Out".
1488  Out.write((char*)&Buffer.front(), Buffer.size());
1489
1490  // Make sure it hits disk now.
1491  Out.flush();
1492}
1493
1494/// WriteBitcodeToStream - Write the specified module to the specified output
1495/// stream.
1496void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1497  // If this is darwin, emit a file header and trailer if needed.
1498  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1499  if (isDarwin)
1500    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1501
1502  // Emit the file header.
1503  Stream.Emit((unsigned)'B', 8);
1504  Stream.Emit((unsigned)'C', 8);
1505  Stream.Emit(0x0, 4);
1506  Stream.Emit(0xC, 4);
1507  Stream.Emit(0xE, 4);
1508  Stream.Emit(0xD, 4);
1509
1510  // Emit the module.
1511  WriteModule(M, Stream);
1512
1513  if (isDarwin)
1514    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1515}
1516