BitcodeWriter.cpp revision 4dc2b39bf89d7c87868008ef8a0f807e0419aca6 
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/TypeSymbolTable.h"
24#include "llvm/ValueSymbolTable.h"
25#include "llvm/Support/MathExtras.h"
26#include "llvm/Support/Streams.h"
27#include "llvm/Support/raw_ostream.h"
28#include "llvm/System/Program.h"
29using namespace llvm;
30
31/// These are manifest constants used by the bitcode writer. They do not need to
32/// be kept in sync with the reader, but need to be consistent within this file.
33enum {
34  CurVersion = 0,
35
36  // VALUE_SYMTAB_BLOCK abbrev id's.
37  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
38  VST_ENTRY_7_ABBREV,
39  VST_ENTRY_6_ABBREV,
40  VST_BBENTRY_6_ABBREV,
41
42  // CONSTANTS_BLOCK abbrev id's.
43  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
44  CONSTANTS_INTEGER_ABBREV,
45  CONSTANTS_CE_CAST_Abbrev,
46  CONSTANTS_NULL_Abbrev,
47
48  // FUNCTION_BLOCK abbrev id's.
49  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
50  FUNCTION_INST_BINOP_ABBREV,
51  FUNCTION_INST_CAST_ABBREV,
52  FUNCTION_INST_RET_VOID_ABBREV,
53  FUNCTION_INST_RET_VAL_ABBREV,
54  FUNCTION_INST_UNREACHABLE_ABBREV
55};
56
57
58static unsigned GetEncodedCastOpcode(unsigned Opcode) {
59  switch (Opcode) {
60  default: assert(0 && "Unknown cast instruction!");
61  case Instruction::Trunc   : return bitc::CAST_TRUNC;
62  case Instruction::ZExt    : return bitc::CAST_ZEXT;
63  case Instruction::SExt    : return bitc::CAST_SEXT;
64  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
65  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
66  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
67  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
68  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
69  case Instruction::FPExt   : return bitc::CAST_FPEXT;
70  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
71  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
72  case Instruction::BitCast : return bitc::CAST_BITCAST;
73  }
74}
75
76static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
77  switch (Opcode) {
78  default: assert(0 && "Unknown binary instruction!");
79  case Instruction::Add:  return bitc::BINOP_ADD;
80  case Instruction::Sub:  return bitc::BINOP_SUB;
81  case Instruction::Mul:  return bitc::BINOP_MUL;
82  case Instruction::UDiv: return bitc::BINOP_UDIV;
83  case Instruction::FDiv:
84  case Instruction::SDiv: return bitc::BINOP_SDIV;
85  case Instruction::URem: return bitc::BINOP_UREM;
86  case Instruction::FRem:
87  case Instruction::SRem: return bitc::BINOP_SREM;
88  case Instruction::Shl:  return bitc::BINOP_SHL;
89  case Instruction::LShr: return bitc::BINOP_LSHR;
90  case Instruction::AShr: return bitc::BINOP_ASHR;
91  case Instruction::And:  return bitc::BINOP_AND;
92  case Instruction::Or:   return bitc::BINOP_OR;
93  case Instruction::Xor:  return bitc::BINOP_XOR;
94  }
95}
96
97
98
99static void WriteStringRecord(unsigned Code, const std::string &Str,
100                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
101  SmallVector<unsigned, 64> Vals;
102
103  // Code: [strchar x N]
104  for (unsigned i = 0, e = Str.size(); i != e; ++i)
105    Vals.push_back(Str[i]);
106
107  // Emit the finished record.
108  Stream.EmitRecord(Code, Vals, AbbrevToUse);
109}
110
111// Emit information about parameter attributes.
112static void WriteAttributeTable(const ValueEnumerator &VE,
113                                BitstreamWriter &Stream) {
114  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
115  if (Attrs.empty()) return;
116
117  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
118
119  SmallVector<uint64_t, 64> Record;
120  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
121    const AttrListPtr &A = Attrs[i];
122    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
123      const AttributeWithIndex &PAWI = A.getSlot(i);
124      Record.push_back(PAWI.Index);
125
126      // FIXME: remove in LLVM 3.0
127      // Store the alignment in the bitcode as a 16-bit raw value instead of a
128      // 5-bit log2 encoded value. Shift the bits above the alignment up by
129      // 11 bits.
130      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
131      if (PAWI.Attrs & Attribute::Alignment)
132        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
133      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
134
135      Record.push_back(FauxAttr);
136    }
137
138    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
139    Record.clear();
140  }
141
142  Stream.ExitBlock();
143}
144
145/// WriteTypeTable - Write out the type table for a module.
146static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
147  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
148
149  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
150  SmallVector<uint64_t, 64> TypeVals;
151
152  // Abbrev for TYPE_CODE_POINTER.
153  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
154  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
155  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
156                            Log2_32_Ceil(VE.getTypes().size()+1)));
157  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
158  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
159
160  // Abbrev for TYPE_CODE_FUNCTION.
161  Abbv = new BitCodeAbbrev();
162  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
163  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
164  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
165  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
166  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
167                            Log2_32_Ceil(VE.getTypes().size()+1)));
168  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
169
170  // Abbrev for TYPE_CODE_STRUCT.
171  Abbv = new BitCodeAbbrev();
172  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
173  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
174  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
175  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
176                            Log2_32_Ceil(VE.getTypes().size()+1)));
177  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
178
179  // Abbrev for TYPE_CODE_ARRAY.
180  Abbv = new BitCodeAbbrev();
181  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
182  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
183  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
184                            Log2_32_Ceil(VE.getTypes().size()+1)));
185  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
186
187  // Emit an entry count so the reader can reserve space.
188  TypeVals.push_back(TypeList.size());
189  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
190  TypeVals.clear();
191
192  // Loop over all of the types, emitting each in turn.
193  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
194    const Type *T = TypeList[i].first;
195    int AbbrevToUse = 0;
196    unsigned Code = 0;
197
198    switch (T->getTypeID()) {
199    default: assert(0 && "Unknown type!");
200    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
201    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
202    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
203    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
204    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
205    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
206    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
207    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
208    case Type::IntegerTyID:
209      // INTEGER: [width]
210      Code = bitc::TYPE_CODE_INTEGER;
211      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
212      break;
213    case Type::PointerTyID: {
214      const PointerType *PTy = cast<PointerType>(T);
215      // POINTER: [pointee type, address space]
216      Code = bitc::TYPE_CODE_POINTER;
217      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
218      unsigned AddressSpace = PTy->getAddressSpace();
219      TypeVals.push_back(AddressSpace);
220      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
221      break;
222    }
223    case Type::FunctionTyID: {
224      const FunctionType *FT = cast<FunctionType>(T);
225      // FUNCTION: [isvararg, attrid, retty, paramty x N]
226      Code = bitc::TYPE_CODE_FUNCTION;
227      TypeVals.push_back(FT->isVarArg());
228      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
229      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
230      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
231        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
232      AbbrevToUse = FunctionAbbrev;
233      break;
234    }
235    case Type::StructTyID: {
236      const StructType *ST = cast<StructType>(T);
237      // STRUCT: [ispacked, eltty x N]
238      Code = bitc::TYPE_CODE_STRUCT;
239      TypeVals.push_back(ST->isPacked());
240      // Output all of the element types.
241      for (StructType::element_iterator I = ST->element_begin(),
242           E = ST->element_end(); I != E; ++I)
243        TypeVals.push_back(VE.getTypeID(*I));
244      AbbrevToUse = StructAbbrev;
245      break;
246    }
247    case Type::ArrayTyID: {
248      const ArrayType *AT = cast<ArrayType>(T);
249      // ARRAY: [numelts, eltty]
250      Code = bitc::TYPE_CODE_ARRAY;
251      TypeVals.push_back(AT->getNumElements());
252      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
253      AbbrevToUse = ArrayAbbrev;
254      break;
255    }
256    case Type::VectorTyID: {
257      const VectorType *VT = cast<VectorType>(T);
258      // VECTOR [numelts, eltty]
259      Code = bitc::TYPE_CODE_VECTOR;
260      TypeVals.push_back(VT->getNumElements());
261      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
262      break;
263    }
264    }
265
266    // Emit the finished record.
267    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
268    TypeVals.clear();
269  }
270
271  Stream.ExitBlock();
272}
273
274static unsigned getEncodedLinkage(const GlobalValue *GV) {
275  switch (GV->getLinkage()) {
276  default: assert(0 && "Invalid linkage!");
277  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
278  case GlobalValue::ExternalLinkage:     return 0;
279  case GlobalValue::WeakAnyLinkage:      return 1;
280  case GlobalValue::AppendingLinkage:    return 2;
281  case GlobalValue::InternalLinkage:     return 3;
282  case GlobalValue::LinkOnceAnyLinkage:  return 4;
283  case GlobalValue::DLLImportLinkage:    return 5;
284  case GlobalValue::DLLExportLinkage:    return 6;
285  case GlobalValue::ExternalWeakLinkage: return 7;
286  case GlobalValue::CommonLinkage:       return 8;
287  case GlobalValue::PrivateLinkage:      return 9;
288  case GlobalValue::WeakODRLinkage:      return 10;
289  case GlobalValue::LinkOnceODRLinkage:  return 11;
290  }
291}
292
293static unsigned getEncodedVisibility(const GlobalValue *GV) {
294  switch (GV->getVisibility()) {
295  default: assert(0 && "Invalid visibility!");
296  case GlobalValue::DefaultVisibility:   return 0;
297  case GlobalValue::HiddenVisibility:    return 1;
298  case GlobalValue::ProtectedVisibility: return 2;
299  }
300}
301
302// Emit top-level description of module, including target triple, inline asm,
303// descriptors for global variables, and function prototype info.
304static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
305                            BitstreamWriter &Stream) {
306  // Emit the list of dependent libraries for the Module.
307  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
308    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
309
310  // Emit various pieces of data attached to a module.
311  if (!M->getTargetTriple().empty())
312    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
313                      0/*TODO*/, Stream);
314  if (!M->getDataLayout().empty())
315    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
316                      0/*TODO*/, Stream);
317  if (!M->getModuleInlineAsm().empty())
318    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
319                      0/*TODO*/, Stream);
320
321  // Emit information about sections and GC, computing how many there are. Also
322  // compute the maximum alignment value.
323  std::map<std::string, unsigned> SectionMap;
324  std::map<std::string, unsigned> GCMap;
325  unsigned MaxAlignment = 0;
326  unsigned MaxGlobalType = 0;
327  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
328       GV != E; ++GV) {
329    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
330    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
331
332    if (!GV->hasSection()) continue;
333    // Give section names unique ID's.
334    unsigned &Entry = SectionMap[GV->getSection()];
335    if (Entry != 0) continue;
336    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
337                      0/*TODO*/, Stream);
338    Entry = SectionMap.size();
339  }
340  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
341    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
342    if (F->hasSection()) {
343      // Give section names unique ID's.
344      unsigned &Entry = SectionMap[F->getSection()];
345      if (!Entry) {
346        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
347                          0/*TODO*/, Stream);
348        Entry = SectionMap.size();
349      }
350    }
351    if (F->hasGC()) {
352      // Same for GC names.
353      unsigned &Entry = GCMap[F->getGC()];
354      if (!Entry) {
355        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
356                          0/*TODO*/, Stream);
357        Entry = GCMap.size();
358      }
359    }
360  }
361
362  // Emit abbrev for globals, now that we know # sections and max alignment.
363  unsigned SimpleGVarAbbrev = 0;
364  if (!M->global_empty()) {
365    // Add an abbrev for common globals with no visibility or thread localness.
366    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
367    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
368    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
369                              Log2_32_Ceil(MaxGlobalType+1)));
370    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
371    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
372    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
373    if (MaxAlignment == 0)                                      // Alignment.
374      Abbv->Add(BitCodeAbbrevOp(0));
375    else {
376      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
377      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
378                               Log2_32_Ceil(MaxEncAlignment+1)));
379    }
380    if (SectionMap.empty())                                    // Section.
381      Abbv->Add(BitCodeAbbrevOp(0));
382    else
383      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
384                               Log2_32_Ceil(SectionMap.size()+1)));
385    // Don't bother emitting vis + thread local.
386    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
387  }
388
389  // Emit the global variable information.
390  SmallVector<unsigned, 64> Vals;
391  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
392       GV != E; ++GV) {
393    unsigned AbbrevToUse = 0;
394
395    // GLOBALVAR: [type, isconst, initid,
396    //             linkage, alignment, section, visibility, threadlocal]
397    Vals.push_back(VE.getTypeID(GV->getType()));
398    Vals.push_back(GV->isConstant());
399    Vals.push_back(GV->isDeclaration() ? 0 :
400                   (VE.getValueID(GV->getInitializer()) + 1));
401    Vals.push_back(getEncodedLinkage(GV));
402    Vals.push_back(Log2_32(GV->getAlignment())+1);
403    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
404    if (GV->isThreadLocal() ||
405        GV->getVisibility() != GlobalValue::DefaultVisibility) {
406      Vals.push_back(getEncodedVisibility(GV));
407      Vals.push_back(GV->isThreadLocal());
408    } else {
409      AbbrevToUse = SimpleGVarAbbrev;
410    }
411
412    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
413    Vals.clear();
414  }
415
416  // Emit the function proto information.
417  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
418    // FUNCTION:  [type, callingconv, isproto, paramattr,
419    //             linkage, alignment, section, visibility, gc]
420    Vals.push_back(VE.getTypeID(F->getType()));
421    Vals.push_back(F->getCallingConv());
422    Vals.push_back(F->isDeclaration());
423    Vals.push_back(getEncodedLinkage(F));
424    Vals.push_back(VE.getAttributeID(F->getAttributes()));
425    Vals.push_back(Log2_32(F->getAlignment())+1);
426    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
427    Vals.push_back(getEncodedVisibility(F));
428    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
429
430    unsigned AbbrevToUse = 0;
431    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
432    Vals.clear();
433  }
434
435
436  // Emit the alias information.
437  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
438       AI != E; ++AI) {
439    Vals.push_back(VE.getTypeID(AI->getType()));
440    Vals.push_back(VE.getValueID(AI->getAliasee()));
441    Vals.push_back(getEncodedLinkage(AI));
442    Vals.push_back(getEncodedVisibility(AI));
443    unsigned AbbrevToUse = 0;
444    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
445    Vals.clear();
446  }
447}
448
449
450static void WriteConstants(unsigned FirstVal, unsigned LastVal,
451                           const ValueEnumerator &VE,
452                           BitstreamWriter &Stream, bool isGlobal) {
453  if (FirstVal == LastVal) return;
454
455  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
456
457  unsigned AggregateAbbrev = 0;
458  unsigned String8Abbrev = 0;
459  unsigned CString7Abbrev = 0;
460  unsigned CString6Abbrev = 0;
461  // If this is a constant pool for the module, emit module-specific abbrevs.
462  if (isGlobal) {
463    // Abbrev for CST_CODE_AGGREGATE.
464    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
465    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
466    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
467    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
468    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
469
470    // Abbrev for CST_CODE_STRING.
471    Abbv = new BitCodeAbbrev();
472    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
473    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
474    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
475    String8Abbrev = Stream.EmitAbbrev(Abbv);
476    // Abbrev for CST_CODE_CSTRING.
477    Abbv = new BitCodeAbbrev();
478    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
479    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
480    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
481    CString7Abbrev = Stream.EmitAbbrev(Abbv);
482    // Abbrev for CST_CODE_CSTRING.
483    Abbv = new BitCodeAbbrev();
484    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
485    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
486    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
487    CString6Abbrev = Stream.EmitAbbrev(Abbv);
488  }
489
490  SmallVector<uint64_t, 64> Record;
491
492  const ValueEnumerator::ValueList &Vals = VE.getValues();
493  const Type *LastTy = 0;
494  for (unsigned i = FirstVal; i != LastVal; ++i) {
495    const Value *V = Vals[i].first;
496    // If we need to switch types, do so now.
497    if (V->getType() != LastTy) {
498      LastTy = V->getType();
499      Record.push_back(VE.getTypeID(LastTy));
500      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
501                        CONSTANTS_SETTYPE_ABBREV);
502      Record.clear();
503    }
504
505    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
506      Record.push_back(unsigned(IA->hasSideEffects()));
507
508      // Add the asm string.
509      const std::string &AsmStr = IA->getAsmString();
510      Record.push_back(AsmStr.size());
511      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
512        Record.push_back(AsmStr[i]);
513
514      // Add the constraint string.
515      const std::string &ConstraintStr = IA->getConstraintString();
516      Record.push_back(ConstraintStr.size());
517      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
518        Record.push_back(ConstraintStr[i]);
519      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
520      Record.clear();
521      continue;
522    }
523    const Constant *C = cast<Constant>(V);
524    unsigned Code = -1U;
525    unsigned AbbrevToUse = 0;
526    if (C->isNullValue()) {
527      Code = bitc::CST_CODE_NULL;
528    } else if (isa<UndefValue>(C)) {
529      Code = bitc::CST_CODE_UNDEF;
530    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
531      if (IV->getBitWidth() <= 64) {
532        int64_t V = IV->getSExtValue();
533        if (V >= 0)
534          Record.push_back(V << 1);
535        else
536          Record.push_back((-V << 1) | 1);
537        Code = bitc::CST_CODE_INTEGER;
538        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
539      } else {                             // Wide integers, > 64 bits in size.
540        // We have an arbitrary precision integer value to write whose
541        // bit width is > 64. However, in canonical unsigned integer
542        // format it is likely that the high bits are going to be zero.
543        // So, we only write the number of active words.
544        unsigned NWords = IV->getValue().getActiveWords();
545        const uint64_t *RawWords = IV->getValue().getRawData();
546        for (unsigned i = 0; i != NWords; ++i) {
547          int64_t V = RawWords[i];
548          if (V >= 0)
549            Record.push_back(V << 1);
550          else
551            Record.push_back((-V << 1) | 1);
552        }
553        Code = bitc::CST_CODE_WIDE_INTEGER;
554      }
555    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
556      Code = bitc::CST_CODE_FLOAT;
557      const Type *Ty = CFP->getType();
558      if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
559        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
560      } else if (Ty == Type::X86_FP80Ty) {
561        // api needed to prevent premature destruction
562        APInt api = CFP->getValueAPF().bitcastToAPInt();
563        const uint64_t *p = api.getRawData();
564        Record.push_back(p[0]);
565        Record.push_back((uint16_t)p[1]);
566      } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
567        APInt api = CFP->getValueAPF().bitcastToAPInt();
568        const uint64_t *p = api.getRawData();
569        Record.push_back(p[0]);
570        Record.push_back(p[1]);
571      } else {
572        assert (0 && "Unknown FP type!");
573      }
574    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
575      // Emit constant strings specially.
576      unsigned NumOps = C->getNumOperands();
577      // If this is a null-terminated string, use the denser CSTRING encoding.
578      if (C->getOperand(NumOps-1)->isNullValue()) {
579        Code = bitc::CST_CODE_CSTRING;
580        --NumOps;  // Don't encode the null, which isn't allowed by char6.
581      } else {
582        Code = bitc::CST_CODE_STRING;
583        AbbrevToUse = String8Abbrev;
584      }
585      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
586      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
587      for (unsigned i = 0; i != NumOps; ++i) {
588        unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
589        Record.push_back(V);
590        isCStr7 &= (V & 128) == 0;
591        if (isCStrChar6)
592          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
593      }
594
595      if (isCStrChar6)
596        AbbrevToUse = CString6Abbrev;
597      else if (isCStr7)
598        AbbrevToUse = CString7Abbrev;
599    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
600               isa<ConstantVector>(V)) {
601      Code = bitc::CST_CODE_AGGREGATE;
602      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
603        Record.push_back(VE.getValueID(C->getOperand(i)));
604      AbbrevToUse = AggregateAbbrev;
605    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
606      switch (CE->getOpcode()) {
607      default:
608        if (Instruction::isCast(CE->getOpcode())) {
609          Code = bitc::CST_CODE_CE_CAST;
610          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
611          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
612          Record.push_back(VE.getValueID(C->getOperand(0)));
613          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
614        } else {
615          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
616          Code = bitc::CST_CODE_CE_BINOP;
617          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
618          Record.push_back(VE.getValueID(C->getOperand(0)));
619          Record.push_back(VE.getValueID(C->getOperand(1)));
620        }
621        break;
622      case Instruction::GetElementPtr:
623        Code = bitc::CST_CODE_CE_GEP;
624        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
625          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
626          Record.push_back(VE.getValueID(C->getOperand(i)));
627        }
628        break;
629      case Instruction::Select:
630        Code = bitc::CST_CODE_CE_SELECT;
631        Record.push_back(VE.getValueID(C->getOperand(0)));
632        Record.push_back(VE.getValueID(C->getOperand(1)));
633        Record.push_back(VE.getValueID(C->getOperand(2)));
634        break;
635      case Instruction::ExtractElement:
636        Code = bitc::CST_CODE_CE_EXTRACTELT;
637        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
638        Record.push_back(VE.getValueID(C->getOperand(0)));
639        Record.push_back(VE.getValueID(C->getOperand(1)));
640        break;
641      case Instruction::InsertElement:
642        Code = bitc::CST_CODE_CE_INSERTELT;
643        Record.push_back(VE.getValueID(C->getOperand(0)));
644        Record.push_back(VE.getValueID(C->getOperand(1)));
645        Record.push_back(VE.getValueID(C->getOperand(2)));
646        break;
647      case Instruction::ShuffleVector:
648        // If the return type and argument types are the same, this is a
649        // standard shufflevector instruction.  If the types are different,
650        // then the shuffle is widening or truncating the input vectors, and
651        // the argument type must also be encoded.
652        if (C->getType() == C->getOperand(0)->getType()) {
653          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
654        } else {
655          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
656          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
657        }
658        Record.push_back(VE.getValueID(C->getOperand(0)));
659        Record.push_back(VE.getValueID(C->getOperand(1)));
660        Record.push_back(VE.getValueID(C->getOperand(2)));
661        break;
662      case Instruction::ICmp:
663      case Instruction::FCmp:
664      case Instruction::VICmp:
665      case Instruction::VFCmp:
666        if (isa<VectorType>(C->getOperand(0)->getType())
667            && (CE->getOpcode() == Instruction::ICmp
668                || CE->getOpcode() == Instruction::FCmp)) {
669          // compare returning vector of Int1Ty
670          assert(0 && "Unsupported constant!");
671        } else {
672          Code = bitc::CST_CODE_CE_CMP;
673        }
674        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
675        Record.push_back(VE.getValueID(C->getOperand(0)));
676        Record.push_back(VE.getValueID(C->getOperand(1)));
677        Record.push_back(CE->getPredicate());
678        break;
679      }
680    } else {
681      assert(0 && "Unknown constant!");
682    }
683    Stream.EmitRecord(Code, Record, AbbrevToUse);
684    Record.clear();
685  }
686
687  Stream.ExitBlock();
688}
689
690static void WriteModuleConstants(const ValueEnumerator &VE,
691                                 BitstreamWriter &Stream) {
692  const ValueEnumerator::ValueList &Vals = VE.getValues();
693
694  // Find the first constant to emit, which is the first non-globalvalue value.
695  // We know globalvalues have been emitted by WriteModuleInfo.
696  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
697    if (!isa<GlobalValue>(Vals[i].first)) {
698      WriteConstants(i, Vals.size(), VE, Stream, true);
699      return;
700    }
701  }
702}
703
704/// PushValueAndType - The file has to encode both the value and type id for
705/// many values, because we need to know what type to create for forward
706/// references.  However, most operands are not forward references, so this type
707/// field is not needed.
708///
709/// This function adds V's value ID to Vals.  If the value ID is higher than the
710/// instruction ID, then it is a forward reference, and it also includes the
711/// type ID.
712static bool PushValueAndType(const Value *V, unsigned InstID,
713                             SmallVector<unsigned, 64> &Vals,
714                             ValueEnumerator &VE) {
715  unsigned ValID = VE.getValueID(V);
716  Vals.push_back(ValID);
717  if (ValID >= InstID) {
718    Vals.push_back(VE.getTypeID(V->getType()));
719    return true;
720  }
721  return false;
722}
723
724/// WriteInstruction - Emit an instruction to the specified stream.
725static void WriteInstruction(const Instruction &I, unsigned InstID,
726                             ValueEnumerator &VE, BitstreamWriter &Stream,
727                             SmallVector<unsigned, 64> &Vals) {
728  unsigned Code = 0;
729  unsigned AbbrevToUse = 0;
730  switch (I.getOpcode()) {
731  default:
732    if (Instruction::isCast(I.getOpcode())) {
733      Code = bitc::FUNC_CODE_INST_CAST;
734      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
735        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
736      Vals.push_back(VE.getTypeID(I.getType()));
737      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
738    } else {
739      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
740      Code = bitc::FUNC_CODE_INST_BINOP;
741      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
742        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
743      Vals.push_back(VE.getValueID(I.getOperand(1)));
744      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
745    }
746    break;
747
748  case Instruction::GetElementPtr:
749    Code = bitc::FUNC_CODE_INST_GEP;
750    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
751      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
752    break;
753  case Instruction::ExtractValue: {
754    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
755    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
756    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
757    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
758      Vals.push_back(*i);
759    break;
760  }
761  case Instruction::InsertValue: {
762    Code = bitc::FUNC_CODE_INST_INSERTVAL;
763    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
764    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
765    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
766    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
767      Vals.push_back(*i);
768    break;
769  }
770  case Instruction::Select:
771    Code = bitc::FUNC_CODE_INST_VSELECT;
772    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
773    Vals.push_back(VE.getValueID(I.getOperand(2)));
774    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
775    break;
776  case Instruction::ExtractElement:
777    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
778    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
779    Vals.push_back(VE.getValueID(I.getOperand(1)));
780    break;
781  case Instruction::InsertElement:
782    Code = bitc::FUNC_CODE_INST_INSERTELT;
783    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
784    Vals.push_back(VE.getValueID(I.getOperand(1)));
785    Vals.push_back(VE.getValueID(I.getOperand(2)));
786    break;
787  case Instruction::ShuffleVector:
788    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
789    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
790    Vals.push_back(VE.getValueID(I.getOperand(1)));
791    Vals.push_back(VE.getValueID(I.getOperand(2)));
792    break;
793  case Instruction::ICmp:
794  case Instruction::FCmp:
795  case Instruction::VICmp:
796  case Instruction::VFCmp:
797    if (I.getOpcode() == Instruction::ICmp
798        || I.getOpcode() == Instruction::FCmp) {
799      // compare returning Int1Ty or vector of Int1Ty
800      Code = bitc::FUNC_CODE_INST_CMP2;
801    } else {
802      Code = bitc::FUNC_CODE_INST_CMP;
803    }
804    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
805    Vals.push_back(VE.getValueID(I.getOperand(1)));
806    Vals.push_back(cast<CmpInst>(I).getPredicate());
807    break;
808
809  case Instruction::Ret:
810    {
811      Code = bitc::FUNC_CODE_INST_RET;
812      unsigned NumOperands = I.getNumOperands();
813      if (NumOperands == 0)
814        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
815      else if (NumOperands == 1) {
816        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
817          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
818      } else {
819        for (unsigned i = 0, e = NumOperands; i != e; ++i)
820          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
821      }
822    }
823    break;
824  case Instruction::Br:
825    {
826      Code = bitc::FUNC_CODE_INST_BR;
827      BranchInst &II(cast<BranchInst>(I));
828      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
829      if (II.isConditional()) {
830        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
831        Vals.push_back(VE.getValueID(II.getCondition()));
832      }
833    }
834    break;
835  case Instruction::Switch:
836    Code = bitc::FUNC_CODE_INST_SWITCH;
837    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
838    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
839      Vals.push_back(VE.getValueID(I.getOperand(i)));
840    break;
841  case Instruction::Invoke: {
842    const InvokeInst *II = cast<InvokeInst>(&I);
843    const Value *Callee(II->getCalledValue());
844    const PointerType *PTy = cast<PointerType>(Callee->getType());
845    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
846    Code = bitc::FUNC_CODE_INST_INVOKE;
847
848    Vals.push_back(VE.getAttributeID(II->getAttributes()));
849    Vals.push_back(II->getCallingConv());
850    Vals.push_back(VE.getValueID(II->getNormalDest()));
851    Vals.push_back(VE.getValueID(II->getUnwindDest()));
852    PushValueAndType(Callee, InstID, Vals, VE);
853
854    // Emit value #'s for the fixed parameters.
855    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
856      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
857
858    // Emit type/value pairs for varargs params.
859    if (FTy->isVarArg()) {
860      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
861           i != e; ++i)
862        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
863    }
864    break;
865  }
866  case Instruction::Unwind:
867    Code = bitc::FUNC_CODE_INST_UNWIND;
868    break;
869  case Instruction::Unreachable:
870    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
871    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
872    break;
873
874  case Instruction::PHI:
875    Code = bitc::FUNC_CODE_INST_PHI;
876    Vals.push_back(VE.getTypeID(I.getType()));
877    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
878      Vals.push_back(VE.getValueID(I.getOperand(i)));
879    break;
880
881  case Instruction::Malloc:
882    Code = bitc::FUNC_CODE_INST_MALLOC;
883    Vals.push_back(VE.getTypeID(I.getType()));
884    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
885    Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
886    break;
887
888  case Instruction::Free:
889    Code = bitc::FUNC_CODE_INST_FREE;
890    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
891    break;
892
893  case Instruction::Alloca:
894    Code = bitc::FUNC_CODE_INST_ALLOCA;
895    Vals.push_back(VE.getTypeID(I.getType()));
896    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
897    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
898    break;
899
900  case Instruction::Load:
901    Code = bitc::FUNC_CODE_INST_LOAD;
902    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
903      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
904
905    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
906    Vals.push_back(cast<LoadInst>(I).isVolatile());
907    break;
908  case Instruction::Store:
909    Code = bitc::FUNC_CODE_INST_STORE2;
910    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
911    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
912    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
913    Vals.push_back(cast<StoreInst>(I).isVolatile());
914    break;
915  case Instruction::Call: {
916    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
917    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
918
919    Code = bitc::FUNC_CODE_INST_CALL;
920
921    const CallInst *CI = cast<CallInst>(&I);
922    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
923    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
924    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
925
926    // Emit value #'s for the fixed parameters.
927    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
928      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
929
930    // Emit type/value pairs for varargs params.
931    if (FTy->isVarArg()) {
932      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
933      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
934           i != e; ++i)
935        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
936    }
937    break;
938  }
939  case Instruction::VAArg:
940    Code = bitc::FUNC_CODE_INST_VAARG;
941    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
942    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
943    Vals.push_back(VE.getTypeID(I.getType())); // restype.
944    break;
945  }
946
947  Stream.EmitRecord(Code, Vals, AbbrevToUse);
948  Vals.clear();
949}
950
951// Emit names for globals/functions etc.
952static void WriteValueSymbolTable(const ValueSymbolTable &VST,
953                                  const ValueEnumerator &VE,
954                                  BitstreamWriter &Stream) {
955  if (VST.empty()) return;
956  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
957
958  // FIXME: Set up the abbrev, we know how many values there are!
959  // FIXME: We know if the type names can use 7-bit ascii.
960  SmallVector<unsigned, 64> NameVals;
961
962  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
963       SI != SE; ++SI) {
964
965    const ValueName &Name = *SI;
966
967    // Figure out the encoding to use for the name.
968    bool is7Bit = true;
969    bool isChar6 = true;
970    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
971         C != E; ++C) {
972      if (isChar6)
973        isChar6 = BitCodeAbbrevOp::isChar6(*C);
974      if ((unsigned char)*C & 128) {
975        is7Bit = false;
976        break;  // don't bother scanning the rest.
977      }
978    }
979
980    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
981
982    // VST_ENTRY:   [valueid, namechar x N]
983    // VST_BBENTRY: [bbid, namechar x N]
984    unsigned Code;
985    if (isa<BasicBlock>(SI->getValue())) {
986      Code = bitc::VST_CODE_BBENTRY;
987      if (isChar6)
988        AbbrevToUse = VST_BBENTRY_6_ABBREV;
989    } else {
990      Code = bitc::VST_CODE_ENTRY;
991      if (isChar6)
992        AbbrevToUse = VST_ENTRY_6_ABBREV;
993      else if (is7Bit)
994        AbbrevToUse = VST_ENTRY_7_ABBREV;
995    }
996
997    NameVals.push_back(VE.getValueID(SI->getValue()));
998    for (const char *P = Name.getKeyData(),
999         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1000      NameVals.push_back((unsigned char)*P);
1001
1002    // Emit the finished record.
1003    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1004    NameVals.clear();
1005  }
1006  Stream.ExitBlock();
1007}
1008
1009/// WriteFunction - Emit a function body to the module stream.
1010static void WriteFunction(const Function &F, ValueEnumerator &VE,
1011                          BitstreamWriter &Stream) {
1012  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1013  VE.incorporateFunction(F);
1014
1015  SmallVector<unsigned, 64> Vals;
1016
1017  // Emit the number of basic blocks, so the reader can create them ahead of
1018  // time.
1019  Vals.push_back(VE.getBasicBlocks().size());
1020  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1021  Vals.clear();
1022
1023  // If there are function-local constants, emit them now.
1024  unsigned CstStart, CstEnd;
1025  VE.getFunctionConstantRange(CstStart, CstEnd);
1026  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1027
1028  // Keep a running idea of what the instruction ID is.
1029  unsigned InstID = CstEnd;
1030
1031  // Finally, emit all the instructions, in order.
1032  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1033    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1034         I != E; ++I) {
1035      WriteInstruction(*I, InstID, VE, Stream, Vals);
1036      if (I->getType() != Type::VoidTy)
1037        ++InstID;
1038    }
1039
1040  // Emit names for all the instructions etc.
1041  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1042
1043  VE.purgeFunction();
1044  Stream.ExitBlock();
1045}
1046
1047/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1048static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1049                                 const ValueEnumerator &VE,
1050                                 BitstreamWriter &Stream) {
1051  if (TST.empty()) return;
1052
1053  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1054
1055  // 7-bit fixed width VST_CODE_ENTRY strings.
1056  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1057  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1058  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1059                            Log2_32_Ceil(VE.getTypes().size()+1)));
1060  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1061  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1062  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1063
1064  SmallVector<unsigned, 64> NameVals;
1065
1066  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1067       TI != TE; ++TI) {
1068    // TST_ENTRY: [typeid, namechar x N]
1069    NameVals.push_back(VE.getTypeID(TI->second));
1070
1071    const std::string &Str = TI->first;
1072    bool is7Bit = true;
1073    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1074      NameVals.push_back((unsigned char)Str[i]);
1075      if (Str[i] & 128)
1076        is7Bit = false;
1077    }
1078
1079    // Emit the finished record.
1080    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1081    NameVals.clear();
1082  }
1083
1084  Stream.ExitBlock();
1085}
1086
1087// Emit blockinfo, which defines the standard abbreviations etc.
1088static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1089  // We only want to emit block info records for blocks that have multiple
1090  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1091  // blocks can defined their abbrevs inline.
1092  Stream.EnterBlockInfoBlock(2);
1093
1094  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1095    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1096    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1097    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1098    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1099    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1100    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1101                                   Abbv) != VST_ENTRY_8_ABBREV)
1102      assert(0 && "Unexpected abbrev ordering!");
1103  }
1104
1105  { // 7-bit fixed width VST_ENTRY strings.
1106    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1107    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1108    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1109    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1110    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1111    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1112                                   Abbv) != VST_ENTRY_7_ABBREV)
1113      assert(0 && "Unexpected abbrev ordering!");
1114  }
1115  { // 6-bit char6 VST_ENTRY strings.
1116    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1117    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1118    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1119    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1120    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1121    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1122                                   Abbv) != VST_ENTRY_6_ABBREV)
1123      assert(0 && "Unexpected abbrev ordering!");
1124  }
1125  { // 6-bit char6 VST_BBENTRY strings.
1126    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1127    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1128    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1129    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1130    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1131    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1132                                   Abbv) != VST_BBENTRY_6_ABBREV)
1133      assert(0 && "Unexpected abbrev ordering!");
1134  }
1135
1136
1137
1138  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1139    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1140    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1141    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1142                              Log2_32_Ceil(VE.getTypes().size()+1)));
1143    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1144                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1145      assert(0 && "Unexpected abbrev ordering!");
1146  }
1147
1148  { // INTEGER abbrev for CONSTANTS_BLOCK.
1149    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1150    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1151    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1152    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1153                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1154      assert(0 && "Unexpected abbrev ordering!");
1155  }
1156
1157  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1158    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1159    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1160    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1161    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1162                              Log2_32_Ceil(VE.getTypes().size()+1)));
1163    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1164
1165    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1166                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1167      assert(0 && "Unexpected abbrev ordering!");
1168  }
1169  { // NULL abbrev for CONSTANTS_BLOCK.
1170    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1171    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1172    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1173                                   Abbv) != CONSTANTS_NULL_Abbrev)
1174      assert(0 && "Unexpected abbrev ordering!");
1175  }
1176
1177  // FIXME: This should only use space for first class types!
1178
1179  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1180    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1181    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1182    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1183    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1184    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1185    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1186                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1187      assert(0 && "Unexpected abbrev ordering!");
1188  }
1189  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1190    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1191    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1192    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1193    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1194    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1195    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1196                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1197      assert(0 && "Unexpected abbrev ordering!");
1198  }
1199  { // INST_CAST abbrev for FUNCTION_BLOCK.
1200    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1201    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1202    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1203    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1204                              Log2_32_Ceil(VE.getTypes().size()+1)));
1205    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1206    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1207                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1208      assert(0 && "Unexpected abbrev ordering!");
1209  }
1210
1211  { // INST_RET abbrev for FUNCTION_BLOCK.
1212    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1213    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1214    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1215                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1216      assert(0 && "Unexpected abbrev ordering!");
1217  }
1218  { // INST_RET abbrev for FUNCTION_BLOCK.
1219    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1220    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1221    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1222    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1223                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1224      assert(0 && "Unexpected abbrev ordering!");
1225  }
1226  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1227    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1228    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1229    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1230                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1231      assert(0 && "Unexpected abbrev ordering!");
1232  }
1233
1234  Stream.ExitBlock();
1235}
1236
1237
1238/// WriteModule - Emit the specified module to the bitstream.
1239static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1240  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1241
1242  // Emit the version number if it is non-zero.
1243  if (CurVersion) {
1244    SmallVector<unsigned, 1> Vals;
1245    Vals.push_back(CurVersion);
1246    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1247  }
1248
1249  // Analyze the module, enumerating globals, functions, etc.
1250  ValueEnumerator VE(M);
1251
1252  // Emit blockinfo, which defines the standard abbreviations etc.
1253  WriteBlockInfo(VE, Stream);
1254
1255  // Emit information about parameter attributes.
1256  WriteAttributeTable(VE, Stream);
1257
1258  // Emit information describing all of the types in the module.
1259  WriteTypeTable(VE, Stream);
1260
1261  // Emit top-level description of module, including target triple, inline asm,
1262  // descriptors for global variables, and function prototype info.
1263  WriteModuleInfo(M, VE, Stream);
1264
1265  // Emit constants.
1266  WriteModuleConstants(VE, Stream);
1267
1268  // If we have any aggregate values in the value table, purge them - these can
1269  // only be used to initialize global variables.  Doing so makes the value
1270  // namespace smaller for code in functions.
1271  int NumNonAggregates = VE.PurgeAggregateValues();
1272  if (NumNonAggregates != -1) {
1273    SmallVector<unsigned, 1> Vals;
1274    Vals.push_back(NumNonAggregates);
1275    Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1276  }
1277
1278  // Emit function bodies.
1279  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1280    if (!I->isDeclaration())
1281      WriteFunction(*I, VE, Stream);
1282
1283  // Emit the type symbol table information.
1284  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1285
1286  // Emit names for globals/functions etc.
1287  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1288
1289  Stream.ExitBlock();
1290}
1291
1292/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1293/// header and trailer to make it compatible with the system archiver.  To do
1294/// this we emit the following header, and then emit a trailer that pads the
1295/// file out to be a multiple of 16 bytes.
1296///
1297/// struct bc_header {
1298///   uint32_t Magic;         // 0x0B17C0DE
1299///   uint32_t Version;       // Version, currently always 0.
1300///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1301///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1302///   uint32_t CPUType;       // CPU specifier.
1303///   ... potentially more later ...
1304/// };
1305enum {
1306  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1307  DarwinBCHeaderSize = 5*4
1308};
1309
1310static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1311                               const std::string &TT) {
1312  unsigned CPUType = ~0U;
1313
1314  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1315  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1316  // specific constants here because they are implicitly part of the Darwin ABI.
1317  enum {
1318    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1319    DARWIN_CPU_TYPE_X86        = 7,
1320    DARWIN_CPU_TYPE_POWERPC    = 18
1321  };
1322
1323  if (TT.find("x86_64-") == 0)
1324    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1325  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1326           TT[4] == '-' && TT[1] - '3' < 6)
1327    CPUType = DARWIN_CPU_TYPE_X86;
1328  else if (TT.find("powerpc-") == 0)
1329    CPUType = DARWIN_CPU_TYPE_POWERPC;
1330  else if (TT.find("powerpc64-") == 0)
1331    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1332
1333  // Traditional Bitcode starts after header.
1334  unsigned BCOffset = DarwinBCHeaderSize;
1335
1336  Stream.Emit(0x0B17C0DE, 32);
1337  Stream.Emit(0         , 32);  // Version.
1338  Stream.Emit(BCOffset  , 32);
1339  Stream.Emit(0         , 32);  // Filled in later.
1340  Stream.Emit(CPUType   , 32);
1341}
1342
1343/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1344/// finalize the header.
1345static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1346  // Update the size field in the header.
1347  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1348
1349  // If the file is not a multiple of 16 bytes, insert dummy padding.
1350  while (BufferSize & 15) {
1351    Stream.Emit(0, 8);
1352    ++BufferSize;
1353  }
1354}
1355
1356
1357/// WriteBitcodeToFile - Write the specified module to the specified output
1358/// stream.
1359void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1360  raw_os_ostream RawOut(Out);
1361  // If writing to stdout, set binary mode.
1362  if (llvm::cout == Out)
1363    sys::Program::ChangeStdoutToBinary();
1364  WriteBitcodeToFile(M, RawOut);
1365}
1366
1367/// WriteBitcodeToFile - Write the specified module to the specified output
1368/// stream.
1369void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1370  std::vector<unsigned char> Buffer;
1371  BitstreamWriter Stream(Buffer);
1372
1373  Buffer.reserve(256*1024);
1374
1375  WriteBitcodeToStream( M, Stream );
1376
1377  // If writing to stdout, set binary mode.
1378  if (&llvm::outs() == &Out)
1379    sys::Program::ChangeStdoutToBinary();
1380
1381  // Write the generated bitstream to "Out".
1382  Out.write((char*)&Buffer.front(), Buffer.size());
1383
1384  // Make sure it hits disk now.
1385  Out.flush();
1386}
1387
1388/// WriteBitcodeToStream - Write the specified module to the specified output
1389/// stream.
1390void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1391  // If this is darwin, emit a file header and trailer if needed.
1392  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1393  if (isDarwin)
1394    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1395
1396  // Emit the file header.
1397  Stream.Emit((unsigned)'B', 8);
1398  Stream.Emit((unsigned)'C', 8);
1399  Stream.Emit(0x0, 4);
1400  Stream.Emit(0xC, 4);
1401  Stream.Emit(0xE, 4);
1402  Stream.Emit(0xD, 4);
1403
1404  // Emit the module.
1405  WriteModule(M, Stream);
1406
1407  if (isDarwin)
1408    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1409}
1410