BitcodeWriter.cpp revision d408f06048797a43b17a7740acb766cc5f0adfbb 
1//===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Bitcode writer implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Bitcode/ReaderWriter.h"
15#include "llvm/Bitcode/BitstreamWriter.h"
16#include "llvm/Bitcode/LLVMBitCodes.h"
17#include "ValueEnumerator.h"
18#include "llvm/Constants.h"
19#include "llvm/DerivedTypes.h"
20#include "llvm/InlineAsm.h"
21#include "llvm/Instructions.h"
22#include "llvm/Module.h"
23#include "llvm/Operator.h"
24#include "llvm/ValueSymbolTable.h"
25#include "llvm/ADT/Triple.h"
26#include "llvm/Support/CommandLine.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/MathExtras.h"
29#include "llvm/Support/raw_ostream.h"
30#include "llvm/Support/Program.h"
31#include <cctype>
32#include <map>
33using namespace llvm;
34
35static cl::opt<bool>
36EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
37                              cl::desc("Turn on experimental support for "
38                                       "use-list order preservation."),
39                              cl::init(false), cl::Hidden);
40
41/// These are manifest constants used by the bitcode writer. They do not need to
42/// be kept in sync with the reader, but need to be consistent within this file.
43enum {
44  CurVersion = 0,
45
46  // VALUE_SYMTAB_BLOCK abbrev id's.
47  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
48  VST_ENTRY_7_ABBREV,
49  VST_ENTRY_6_ABBREV,
50  VST_BBENTRY_6_ABBREV,
51
52  // CONSTANTS_BLOCK abbrev id's.
53  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
54  CONSTANTS_INTEGER_ABBREV,
55  CONSTANTS_CE_CAST_Abbrev,
56  CONSTANTS_NULL_Abbrev,
57
58  // FUNCTION_BLOCK abbrev id's.
59  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
60  FUNCTION_INST_BINOP_ABBREV,
61  FUNCTION_INST_BINOP_FLAGS_ABBREV,
62  FUNCTION_INST_CAST_ABBREV,
63  FUNCTION_INST_RET_VOID_ABBREV,
64  FUNCTION_INST_RET_VAL_ABBREV,
65  FUNCTION_INST_UNREACHABLE_ABBREV
66};
67
68static unsigned GetEncodedCastOpcode(unsigned Opcode) {
69  switch (Opcode) {
70  default: llvm_unreachable("Unknown cast instruction!");
71  case Instruction::Trunc   : return bitc::CAST_TRUNC;
72  case Instruction::ZExt    : return bitc::CAST_ZEXT;
73  case Instruction::SExt    : return bitc::CAST_SEXT;
74  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
75  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
76  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
77  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
78  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
79  case Instruction::FPExt   : return bitc::CAST_FPEXT;
80  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
81  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
82  case Instruction::BitCast : return bitc::CAST_BITCAST;
83  }
84}
85
86static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
87  switch (Opcode) {
88  default: llvm_unreachable("Unknown binary instruction!");
89  case Instruction::Add:
90  case Instruction::FAdd: return bitc::BINOP_ADD;
91  case Instruction::Sub:
92  case Instruction::FSub: return bitc::BINOP_SUB;
93  case Instruction::Mul:
94  case Instruction::FMul: return bitc::BINOP_MUL;
95  case Instruction::UDiv: return bitc::BINOP_UDIV;
96  case Instruction::FDiv:
97  case Instruction::SDiv: return bitc::BINOP_SDIV;
98  case Instruction::URem: return bitc::BINOP_UREM;
99  case Instruction::FRem:
100  case Instruction::SRem: return bitc::BINOP_SREM;
101  case Instruction::Shl:  return bitc::BINOP_SHL;
102  case Instruction::LShr: return bitc::BINOP_LSHR;
103  case Instruction::AShr: return bitc::BINOP_ASHR;
104  case Instruction::And:  return bitc::BINOP_AND;
105  case Instruction::Or:   return bitc::BINOP_OR;
106  case Instruction::Xor:  return bitc::BINOP_XOR;
107  }
108}
109
110static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
111  switch (Op) {
112  default: llvm_unreachable("Unknown RMW operation!");
113  case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
114  case AtomicRMWInst::Add: return bitc::RMW_ADD;
115  case AtomicRMWInst::Sub: return bitc::RMW_SUB;
116  case AtomicRMWInst::And: return bitc::RMW_AND;
117  case AtomicRMWInst::Nand: return bitc::RMW_NAND;
118  case AtomicRMWInst::Or: return bitc::RMW_OR;
119  case AtomicRMWInst::Xor: return bitc::RMW_XOR;
120  case AtomicRMWInst::Max: return bitc::RMW_MAX;
121  case AtomicRMWInst::Min: return bitc::RMW_MIN;
122  case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
123  case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
124  }
125}
126
127static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
128  switch (Ordering) {
129  case NotAtomic: return bitc::ORDERING_NOTATOMIC;
130  case Unordered: return bitc::ORDERING_UNORDERED;
131  case Monotonic: return bitc::ORDERING_MONOTONIC;
132  case Acquire: return bitc::ORDERING_ACQUIRE;
133  case Release: return bitc::ORDERING_RELEASE;
134  case AcquireRelease: return bitc::ORDERING_ACQREL;
135  case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
136  }
137  llvm_unreachable("Invalid ordering");
138}
139
140static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
141  switch (SynchScope) {
142  case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
143  case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
144  }
145  llvm_unreachable("Invalid synch scope");
146}
147
148static void WriteStringRecord(unsigned Code, StringRef Str,
149                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
150  SmallVector<unsigned, 64> Vals;
151
152  // Code: [strchar x N]
153  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
154    if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
155      AbbrevToUse = 0;
156    Vals.push_back(Str[i]);
157  }
158
159  // Emit the finished record.
160  Stream.EmitRecord(Code, Vals, AbbrevToUse);
161}
162
163// Emit information about parameter attributes.
164static void WriteAttributeTable(const ValueEnumerator &VE,
165                                BitstreamWriter &Stream) {
166  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
167  if (Attrs.empty()) return;
168
169  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
170
171  SmallVector<uint64_t, 64> Record;
172  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
173    const AttrListPtr &A = Attrs[i];
174    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
175      const AttributeWithIndex &PAWI = A.getSlot(i);
176      Record.push_back(PAWI.Index);
177
178      // FIXME: remove in LLVM 3.0
179      // Store the alignment in the bitcode as a 16-bit raw value instead of a
180      // 5-bit log2 encoded value. Shift the bits above the alignment up by
181      // 11 bits.
182      uint64_t FauxAttr = PAWI.Attrs.Raw() & 0xffff;
183      if (PAWI.Attrs & Attribute::Alignment)
184        FauxAttr |= (1ull<<16)<<
185            (((PAWI.Attrs & Attribute::Alignment).Raw()-1) >> 16);
186      FauxAttr |= (PAWI.Attrs.Raw() & (0x3FFull << 21)) << 11;
187
188      Record.push_back(FauxAttr);
189    }
190
191    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
192    Record.clear();
193  }
194
195  Stream.ExitBlock();
196}
197
198/// WriteTypeTable - Write out the type table for a module.
199static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
200  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
201
202  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
203  SmallVector<uint64_t, 64> TypeVals;
204
205  uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
206
207  // Abbrev for TYPE_CODE_POINTER.
208  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
209  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
210  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
211  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
212  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
213
214  // Abbrev for TYPE_CODE_FUNCTION.
215  Abbv = new BitCodeAbbrev();
216  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
217  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
218  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
219  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
220
221  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
222
223  // Abbrev for TYPE_CODE_STRUCT_ANON.
224  Abbv = new BitCodeAbbrev();
225  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
226  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
227  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
228  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
229
230  unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
231
232  // Abbrev for TYPE_CODE_STRUCT_NAME.
233  Abbv = new BitCodeAbbrev();
234  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
235  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
236  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
237  unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
238
239  // Abbrev for TYPE_CODE_STRUCT_NAMED.
240  Abbv = new BitCodeAbbrev();
241  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
242  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
243  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
244  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
245
246  unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
247
248  // Abbrev for TYPE_CODE_ARRAY.
249  Abbv = new BitCodeAbbrev();
250  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
251  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
252  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
253
254  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
255
256  // Emit an entry count so the reader can reserve space.
257  TypeVals.push_back(TypeList.size());
258  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
259  TypeVals.clear();
260
261  // Loop over all of the types, emitting each in turn.
262  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
263    Type *T = TypeList[i];
264    int AbbrevToUse = 0;
265    unsigned Code = 0;
266
267    switch (T->getTypeID()) {
268    default: llvm_unreachable("Unknown type!");
269    case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;   break;
270    case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;   break;
271    case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;  break;
272    case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE; break;
273    case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80; break;
274    case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128; break;
275    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
276    case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;  break;
277    case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA; break;
278    case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX; break;
279    case Type::IntegerTyID:
280      // INTEGER: [width]
281      Code = bitc::TYPE_CODE_INTEGER;
282      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
283      break;
284    case Type::PointerTyID: {
285      PointerType *PTy = cast<PointerType>(T);
286      // POINTER: [pointee type, address space]
287      Code = bitc::TYPE_CODE_POINTER;
288      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
289      unsigned AddressSpace = PTy->getAddressSpace();
290      TypeVals.push_back(AddressSpace);
291      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
292      break;
293    }
294    case Type::FunctionTyID: {
295      FunctionType *FT = cast<FunctionType>(T);
296      // FUNCTION: [isvararg, retty, paramty x N]
297      Code = bitc::TYPE_CODE_FUNCTION;
298      TypeVals.push_back(FT->isVarArg());
299      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
300      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
301        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
302      AbbrevToUse = FunctionAbbrev;
303      break;
304    }
305    case Type::StructTyID: {
306      StructType *ST = cast<StructType>(T);
307      // STRUCT: [ispacked, eltty x N]
308      TypeVals.push_back(ST->isPacked());
309      // Output all of the element types.
310      for (StructType::element_iterator I = ST->element_begin(),
311           E = ST->element_end(); I != E; ++I)
312        TypeVals.push_back(VE.getTypeID(*I));
313
314      if (ST->isLiteral()) {
315        Code = bitc::TYPE_CODE_STRUCT_ANON;
316        AbbrevToUse = StructAnonAbbrev;
317      } else {
318        if (ST->isOpaque()) {
319          Code = bitc::TYPE_CODE_OPAQUE;
320        } else {
321          Code = bitc::TYPE_CODE_STRUCT_NAMED;
322          AbbrevToUse = StructNamedAbbrev;
323        }
324
325        // Emit the name if it is present.
326        if (!ST->getName().empty())
327          WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
328                            StructNameAbbrev, Stream);
329      }
330      break;
331    }
332    case Type::ArrayTyID: {
333      ArrayType *AT = cast<ArrayType>(T);
334      // ARRAY: [numelts, eltty]
335      Code = bitc::TYPE_CODE_ARRAY;
336      TypeVals.push_back(AT->getNumElements());
337      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
338      AbbrevToUse = ArrayAbbrev;
339      break;
340    }
341    case Type::VectorTyID: {
342      VectorType *VT = cast<VectorType>(T);
343      // VECTOR [numelts, eltty]
344      Code = bitc::TYPE_CODE_VECTOR;
345      TypeVals.push_back(VT->getNumElements());
346      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
347      break;
348    }
349    }
350
351    // Emit the finished record.
352    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
353    TypeVals.clear();
354  }
355
356  Stream.ExitBlock();
357}
358
359static unsigned getEncodedLinkage(const GlobalValue *GV) {
360  switch (GV->getLinkage()) {
361  case GlobalValue::ExternalLinkage:                 return 0;
362  case GlobalValue::WeakAnyLinkage:                  return 1;
363  case GlobalValue::AppendingLinkage:                return 2;
364  case GlobalValue::InternalLinkage:                 return 3;
365  case GlobalValue::LinkOnceAnyLinkage:              return 4;
366  case GlobalValue::DLLImportLinkage:                return 5;
367  case GlobalValue::DLLExportLinkage:                return 6;
368  case GlobalValue::ExternalWeakLinkage:             return 7;
369  case GlobalValue::CommonLinkage:                   return 8;
370  case GlobalValue::PrivateLinkage:                  return 9;
371  case GlobalValue::WeakODRLinkage:                  return 10;
372  case GlobalValue::LinkOnceODRLinkage:              return 11;
373  case GlobalValue::AvailableExternallyLinkage:      return 12;
374  case GlobalValue::LinkerPrivateLinkage:            return 13;
375  case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
376  case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
377  }
378  llvm_unreachable("Invalid linkage");
379}
380
381static unsigned getEncodedVisibility(const GlobalValue *GV) {
382  switch (GV->getVisibility()) {
383  case GlobalValue::DefaultVisibility:   return 0;
384  case GlobalValue::HiddenVisibility:    return 1;
385  case GlobalValue::ProtectedVisibility: return 2;
386  }
387  llvm_unreachable("Invalid visibility");
388}
389
390// Emit top-level description of module, including target triple, inline asm,
391// descriptors for global variables, and function prototype info.
392static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
393                            BitstreamWriter &Stream) {
394  // Emit the list of dependent libraries for the Module.
395  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
396    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
397
398  // Emit various pieces of data attached to a module.
399  if (!M->getTargetTriple().empty())
400    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
401                      0/*TODO*/, Stream);
402  if (!M->getDataLayout().empty())
403    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
404                      0/*TODO*/, Stream);
405  if (!M->getModuleInlineAsm().empty())
406    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
407                      0/*TODO*/, Stream);
408
409  // Emit information about sections and GC, computing how many there are. Also
410  // compute the maximum alignment value.
411  std::map<std::string, unsigned> SectionMap;
412  std::map<std::string, unsigned> GCMap;
413  unsigned MaxAlignment = 0;
414  unsigned MaxGlobalType = 0;
415  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
416       GV != E; ++GV) {
417    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
418    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
419    if (GV->hasSection()) {
420      // Give section names unique ID's.
421      unsigned &Entry = SectionMap[GV->getSection()];
422      if (!Entry) {
423        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
424                          0/*TODO*/, Stream);
425        Entry = SectionMap.size();
426      }
427    }
428  }
429  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
430    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
431    if (F->hasSection()) {
432      // Give section names unique ID's.
433      unsigned &Entry = SectionMap[F->getSection()];
434      if (!Entry) {
435        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
436                          0/*TODO*/, Stream);
437        Entry = SectionMap.size();
438      }
439    }
440    if (F->hasGC()) {
441      // Same for GC names.
442      unsigned &Entry = GCMap[F->getGC()];
443      if (!Entry) {
444        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
445                          0/*TODO*/, Stream);
446        Entry = GCMap.size();
447      }
448    }
449  }
450
451  // Emit abbrev for globals, now that we know # sections and max alignment.
452  unsigned SimpleGVarAbbrev = 0;
453  if (!M->global_empty()) {
454    // Add an abbrev for common globals with no visibility or thread localness.
455    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
456    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
457    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
458                              Log2_32_Ceil(MaxGlobalType+1)));
459    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
460    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
461    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
462    if (MaxAlignment == 0)                                      // Alignment.
463      Abbv->Add(BitCodeAbbrevOp(0));
464    else {
465      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
466      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
467                               Log2_32_Ceil(MaxEncAlignment+1)));
468    }
469    if (SectionMap.empty())                                    // Section.
470      Abbv->Add(BitCodeAbbrevOp(0));
471    else
472      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
473                               Log2_32_Ceil(SectionMap.size()+1)));
474    // Don't bother emitting vis + thread local.
475    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
476  }
477
478  // Emit the global variable information.
479  SmallVector<unsigned, 64> Vals;
480  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
481       GV != E; ++GV) {
482    unsigned AbbrevToUse = 0;
483
484    // GLOBALVAR: [type, isconst, initid,
485    //             linkage, alignment, section, visibility, threadlocal,
486    //             unnamed_addr]
487    Vals.push_back(VE.getTypeID(GV->getType()));
488    Vals.push_back(GV->isConstant());
489    Vals.push_back(GV->isDeclaration() ? 0 :
490                   (VE.getValueID(GV->getInitializer()) + 1));
491    Vals.push_back(getEncodedLinkage(GV));
492    Vals.push_back(Log2_32(GV->getAlignment())+1);
493    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
494    if (GV->isThreadLocal() ||
495        GV->getVisibility() != GlobalValue::DefaultVisibility ||
496        GV->hasUnnamedAddr()) {
497      Vals.push_back(getEncodedVisibility(GV));
498      Vals.push_back(GV->isThreadLocal());
499      Vals.push_back(GV->hasUnnamedAddr());
500    } else {
501      AbbrevToUse = SimpleGVarAbbrev;
502    }
503
504    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
505    Vals.clear();
506  }
507
508  // Emit the function proto information.
509  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
510    // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
511    //             section, visibility, gc, unnamed_addr]
512    Vals.push_back(VE.getTypeID(F->getType()));
513    Vals.push_back(F->getCallingConv());
514    Vals.push_back(F->isDeclaration());
515    Vals.push_back(getEncodedLinkage(F));
516    Vals.push_back(VE.getAttributeID(F->getAttributes()));
517    Vals.push_back(Log2_32(F->getAlignment())+1);
518    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
519    Vals.push_back(getEncodedVisibility(F));
520    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
521    Vals.push_back(F->hasUnnamedAddr());
522
523    unsigned AbbrevToUse = 0;
524    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
525    Vals.clear();
526  }
527
528  // Emit the alias information.
529  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
530       AI != E; ++AI) {
531    // ALIAS: [alias type, aliasee val#, linkage, visibility]
532    Vals.push_back(VE.getTypeID(AI->getType()));
533    Vals.push_back(VE.getValueID(AI->getAliasee()));
534    Vals.push_back(getEncodedLinkage(AI));
535    Vals.push_back(getEncodedVisibility(AI));
536    unsigned AbbrevToUse = 0;
537    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
538    Vals.clear();
539  }
540}
541
542static uint64_t GetOptimizationFlags(const Value *V) {
543  uint64_t Flags = 0;
544
545  if (const OverflowingBinaryOperator *OBO =
546        dyn_cast<OverflowingBinaryOperator>(V)) {
547    if (OBO->hasNoSignedWrap())
548      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
549    if (OBO->hasNoUnsignedWrap())
550      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
551  } else if (const PossiblyExactOperator *PEO =
552               dyn_cast<PossiblyExactOperator>(V)) {
553    if (PEO->isExact())
554      Flags |= 1 << bitc::PEO_EXACT;
555  }
556
557  return Flags;
558}
559
560static void WriteMDNode(const MDNode *N,
561                        const ValueEnumerator &VE,
562                        BitstreamWriter &Stream,
563                        SmallVector<uint64_t, 64> &Record) {
564  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
565    if (N->getOperand(i)) {
566      Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
567      Record.push_back(VE.getValueID(N->getOperand(i)));
568    } else {
569      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
570      Record.push_back(0);
571    }
572  }
573  unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
574                                           bitc::METADATA_NODE;
575  Stream.EmitRecord(MDCode, Record, 0);
576  Record.clear();
577}
578
579static void WriteModuleMetadata(const Module *M,
580                                const ValueEnumerator &VE,
581                                BitstreamWriter &Stream) {
582  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
583  bool StartedMetadataBlock = false;
584  unsigned MDSAbbrev = 0;
585  SmallVector<uint64_t, 64> Record;
586  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
587
588    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
589      if (!N->isFunctionLocal() || !N->getFunction()) {
590        if (!StartedMetadataBlock) {
591          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
592          StartedMetadataBlock = true;
593        }
594        WriteMDNode(N, VE, Stream, Record);
595      }
596    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
597      if (!StartedMetadataBlock)  {
598        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
599
600        // Abbrev for METADATA_STRING.
601        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
602        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
603        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
604        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
605        MDSAbbrev = Stream.EmitAbbrev(Abbv);
606        StartedMetadataBlock = true;
607      }
608
609      // Code: [strchar x N]
610      Record.append(MDS->begin(), MDS->end());
611
612      // Emit the finished record.
613      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
614      Record.clear();
615    }
616  }
617
618  // Write named metadata.
619  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
620       E = M->named_metadata_end(); I != E; ++I) {
621    const NamedMDNode *NMD = I;
622    if (!StartedMetadataBlock)  {
623      Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
624      StartedMetadataBlock = true;
625    }
626
627    // Write name.
628    StringRef Str = NMD->getName();
629    for (unsigned i = 0, e = Str.size(); i != e; ++i)
630      Record.push_back(Str[i]);
631    Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
632    Record.clear();
633
634    // Write named metadata operands.
635    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
636      Record.push_back(VE.getValueID(NMD->getOperand(i)));
637    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
638    Record.clear();
639  }
640
641  if (StartedMetadataBlock)
642    Stream.ExitBlock();
643}
644
645static void WriteFunctionLocalMetadata(const Function &F,
646                                       const ValueEnumerator &VE,
647                                       BitstreamWriter &Stream) {
648  bool StartedMetadataBlock = false;
649  SmallVector<uint64_t, 64> Record;
650  const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
651  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
652    if (const MDNode *N = Vals[i])
653      if (N->isFunctionLocal() && N->getFunction() == &F) {
654        if (!StartedMetadataBlock) {
655          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
656          StartedMetadataBlock = true;
657        }
658        WriteMDNode(N, VE, Stream, Record);
659      }
660
661  if (StartedMetadataBlock)
662    Stream.ExitBlock();
663}
664
665static void WriteMetadataAttachment(const Function &F,
666                                    const ValueEnumerator &VE,
667                                    BitstreamWriter &Stream) {
668  Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
669
670  SmallVector<uint64_t, 64> Record;
671
672  // Write metadata attachments
673  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
674  SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
675
676  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
677    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
678         I != E; ++I) {
679      MDs.clear();
680      I->getAllMetadataOtherThanDebugLoc(MDs);
681
682      // If no metadata, ignore instruction.
683      if (MDs.empty()) continue;
684
685      Record.push_back(VE.getInstructionID(I));
686
687      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
688        Record.push_back(MDs[i].first);
689        Record.push_back(VE.getValueID(MDs[i].second));
690      }
691      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
692      Record.clear();
693    }
694
695  Stream.ExitBlock();
696}
697
698static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
699  SmallVector<uint64_t, 64> Record;
700
701  // Write metadata kinds
702  // METADATA_KIND - [n x [id, name]]
703  SmallVector<StringRef, 4> Names;
704  M->getMDKindNames(Names);
705
706  if (Names.empty()) return;
707
708  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
709
710  for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
711    Record.push_back(MDKindID);
712    StringRef KName = Names[MDKindID];
713    Record.append(KName.begin(), KName.end());
714
715    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
716    Record.clear();
717  }
718
719  Stream.ExitBlock();
720}
721
722static void WriteConstants(unsigned FirstVal, unsigned LastVal,
723                           const ValueEnumerator &VE,
724                           BitstreamWriter &Stream, bool isGlobal) {
725  if (FirstVal == LastVal) return;
726
727  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
728
729  unsigned AggregateAbbrev = 0;
730  unsigned String8Abbrev = 0;
731  unsigned CString7Abbrev = 0;
732  unsigned CString6Abbrev = 0;
733  // If this is a constant pool for the module, emit module-specific abbrevs.
734  if (isGlobal) {
735    // Abbrev for CST_CODE_AGGREGATE.
736    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
737    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
738    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
739    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
740    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
741
742    // Abbrev for CST_CODE_STRING.
743    Abbv = new BitCodeAbbrev();
744    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
745    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
746    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
747    String8Abbrev = Stream.EmitAbbrev(Abbv);
748    // Abbrev for CST_CODE_CSTRING.
749    Abbv = new BitCodeAbbrev();
750    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
751    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
752    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
753    CString7Abbrev = Stream.EmitAbbrev(Abbv);
754    // Abbrev for CST_CODE_CSTRING.
755    Abbv = new BitCodeAbbrev();
756    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
757    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
758    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
759    CString6Abbrev = Stream.EmitAbbrev(Abbv);
760  }
761
762  SmallVector<uint64_t, 64> Record;
763
764  const ValueEnumerator::ValueList &Vals = VE.getValues();
765  Type *LastTy = 0;
766  for (unsigned i = FirstVal; i != LastVal; ++i) {
767    const Value *V = Vals[i].first;
768    // If we need to switch types, do so now.
769    if (V->getType() != LastTy) {
770      LastTy = V->getType();
771      Record.push_back(VE.getTypeID(LastTy));
772      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
773                        CONSTANTS_SETTYPE_ABBREV);
774      Record.clear();
775    }
776
777    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
778      Record.push_back(unsigned(IA->hasSideEffects()) |
779                       unsigned(IA->isAlignStack()) << 1);
780
781      // Add the asm string.
782      const std::string &AsmStr = IA->getAsmString();
783      Record.push_back(AsmStr.size());
784      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
785        Record.push_back(AsmStr[i]);
786
787      // Add the constraint string.
788      const std::string &ConstraintStr = IA->getConstraintString();
789      Record.push_back(ConstraintStr.size());
790      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
791        Record.push_back(ConstraintStr[i]);
792      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
793      Record.clear();
794      continue;
795    }
796    const Constant *C = cast<Constant>(V);
797    unsigned Code = -1U;
798    unsigned AbbrevToUse = 0;
799    if (C->isNullValue()) {
800      Code = bitc::CST_CODE_NULL;
801    } else if (isa<UndefValue>(C)) {
802      Code = bitc::CST_CODE_UNDEF;
803    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
804      if (IV->getBitWidth() <= 64) {
805        uint64_t V = IV->getSExtValue();
806        if ((int64_t)V >= 0)
807          Record.push_back(V << 1);
808        else
809          Record.push_back((-V << 1) | 1);
810        Code = bitc::CST_CODE_INTEGER;
811        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
812      } else {                             // Wide integers, > 64 bits in size.
813        // We have an arbitrary precision integer value to write whose
814        // bit width is > 64. However, in canonical unsigned integer
815        // format it is likely that the high bits are going to be zero.
816        // So, we only write the number of active words.
817        unsigned NWords = IV->getValue().getActiveWords();
818        const uint64_t *RawWords = IV->getValue().getRawData();
819        for (unsigned i = 0; i != NWords; ++i) {
820          int64_t V = RawWords[i];
821          if (V >= 0)
822            Record.push_back(V << 1);
823          else
824            Record.push_back((-V << 1) | 1);
825        }
826        Code = bitc::CST_CODE_WIDE_INTEGER;
827      }
828    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
829      Code = bitc::CST_CODE_FLOAT;
830      Type *Ty = CFP->getType();
831      if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
832        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
833      } else if (Ty->isX86_FP80Ty()) {
834        // api needed to prevent premature destruction
835        // bits are not in the same order as a normal i80 APInt, compensate.
836        APInt api = CFP->getValueAPF().bitcastToAPInt();
837        const uint64_t *p = api.getRawData();
838        Record.push_back((p[1] << 48) | (p[0] >> 16));
839        Record.push_back(p[0] & 0xffffLL);
840      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
841        APInt api = CFP->getValueAPF().bitcastToAPInt();
842        const uint64_t *p = api.getRawData();
843        Record.push_back(p[0]);
844        Record.push_back(p[1]);
845      } else {
846        assert (0 && "Unknown FP type!");
847      }
848    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
849      const ConstantArray *CA = cast<ConstantArray>(C);
850      // Emit constant strings specially.
851      unsigned NumOps = CA->getNumOperands();
852      // If this is a null-terminated string, use the denser CSTRING encoding.
853      if (CA->getOperand(NumOps-1)->isNullValue()) {
854        Code = bitc::CST_CODE_CSTRING;
855        --NumOps;  // Don't encode the null, which isn't allowed by char6.
856      } else {
857        Code = bitc::CST_CODE_STRING;
858        AbbrevToUse = String8Abbrev;
859      }
860      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
861      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
862      for (unsigned i = 0; i != NumOps; ++i) {
863        unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
864        Record.push_back(V);
865        isCStr7 &= (V & 128) == 0;
866        if (isCStrChar6)
867          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
868      }
869
870      if (isCStrChar6)
871        AbbrevToUse = CString6Abbrev;
872      else if (isCStr7)
873        AbbrevToUse = CString7Abbrev;
874    } else if (isa<ConstantDataSequential>(C) &&
875               cast<ConstantDataSequential>(C)->isString()) {
876      const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
877      // Emit constant strings specially.
878      unsigned NumElts = Str->getNumElements();
879      // If this is a null-terminated string, use the denser CSTRING encoding.
880      if (Str->isCString()) {
881        Code = bitc::CST_CODE_CSTRING;
882        --NumElts;  // Don't encode the null, which isn't allowed by char6.
883      } else {
884        Code = bitc::CST_CODE_STRING;
885        AbbrevToUse = String8Abbrev;
886      }
887      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
888      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
889      for (unsigned i = 0; i != NumElts; ++i) {
890        unsigned char V = Str->getElementAsInteger(i);
891        Record.push_back(V);
892        isCStr7 &= (V & 128) == 0;
893        if (isCStrChar6)
894          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
895      }
896
897      if (isCStrChar6)
898        AbbrevToUse = CString6Abbrev;
899      else if (isCStr7)
900        AbbrevToUse = CString7Abbrev;
901    } else if (const ConstantDataSequential *CDS =
902                  dyn_cast<ConstantDataSequential>(C)) {
903      Type *EltTy = CDS->getType()->getElementType();
904      if (isa<IntegerType>(EltTy)) {
905        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
906          Record.push_back(CDS->getElementAsInteger(i));
907      } else if (EltTy->isFloatTy()) {
908        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
909          union { float F; uint32_t I; };
910          F = CDS->getElementAsFloat(i);
911          Record.push_back(I);
912        }
913      } else {
914        assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
915        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
916          union { double F; uint64_t I; };
917          F = CDS->getElementAsDouble(i);
918          Record.push_back(I);
919        }
920      }
921    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
922               isa<ConstantVector>(C)) {
923      Code = bitc::CST_CODE_AGGREGATE;
924      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
925        Record.push_back(VE.getValueID(C->getOperand(i)));
926      AbbrevToUse = AggregateAbbrev;
927    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
928      switch (CE->getOpcode()) {
929      default:
930        if (Instruction::isCast(CE->getOpcode())) {
931          Code = bitc::CST_CODE_CE_CAST;
932          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
933          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
934          Record.push_back(VE.getValueID(C->getOperand(0)));
935          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
936        } else {
937          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
938          Code = bitc::CST_CODE_CE_BINOP;
939          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
940          Record.push_back(VE.getValueID(C->getOperand(0)));
941          Record.push_back(VE.getValueID(C->getOperand(1)));
942          uint64_t Flags = GetOptimizationFlags(CE);
943          if (Flags != 0)
944            Record.push_back(Flags);
945        }
946        break;
947      case Instruction::GetElementPtr:
948        Code = bitc::CST_CODE_CE_GEP;
949        if (cast<GEPOperator>(C)->isInBounds())
950          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
951        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
952          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
953          Record.push_back(VE.getValueID(C->getOperand(i)));
954        }
955        break;
956      case Instruction::Select:
957        Code = bitc::CST_CODE_CE_SELECT;
958        Record.push_back(VE.getValueID(C->getOperand(0)));
959        Record.push_back(VE.getValueID(C->getOperand(1)));
960        Record.push_back(VE.getValueID(C->getOperand(2)));
961        break;
962      case Instruction::ExtractElement:
963        Code = bitc::CST_CODE_CE_EXTRACTELT;
964        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
965        Record.push_back(VE.getValueID(C->getOperand(0)));
966        Record.push_back(VE.getValueID(C->getOperand(1)));
967        break;
968      case Instruction::InsertElement:
969        Code = bitc::CST_CODE_CE_INSERTELT;
970        Record.push_back(VE.getValueID(C->getOperand(0)));
971        Record.push_back(VE.getValueID(C->getOperand(1)));
972        Record.push_back(VE.getValueID(C->getOperand(2)));
973        break;
974      case Instruction::ShuffleVector:
975        // If the return type and argument types are the same, this is a
976        // standard shufflevector instruction.  If the types are different,
977        // then the shuffle is widening or truncating the input vectors, and
978        // the argument type must also be encoded.
979        if (C->getType() == C->getOperand(0)->getType()) {
980          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
981        } else {
982          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
983          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
984        }
985        Record.push_back(VE.getValueID(C->getOperand(0)));
986        Record.push_back(VE.getValueID(C->getOperand(1)));
987        Record.push_back(VE.getValueID(C->getOperand(2)));
988        break;
989      case Instruction::ICmp:
990      case Instruction::FCmp:
991        Code = bitc::CST_CODE_CE_CMP;
992        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
993        Record.push_back(VE.getValueID(C->getOperand(0)));
994        Record.push_back(VE.getValueID(C->getOperand(1)));
995        Record.push_back(CE->getPredicate());
996        break;
997      }
998    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
999      Code = bitc::CST_CODE_BLOCKADDRESS;
1000      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1001      Record.push_back(VE.getValueID(BA->getFunction()));
1002      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1003    } else {
1004#ifndef NDEBUG
1005      C->dump();
1006#endif
1007      llvm_unreachable("Unknown constant!");
1008    }
1009    Stream.EmitRecord(Code, Record, AbbrevToUse);
1010    Record.clear();
1011  }
1012
1013  Stream.ExitBlock();
1014}
1015
1016static void WriteModuleConstants(const ValueEnumerator &VE,
1017                                 BitstreamWriter &Stream) {
1018  const ValueEnumerator::ValueList &Vals = VE.getValues();
1019
1020  // Find the first constant to emit, which is the first non-globalvalue value.
1021  // We know globalvalues have been emitted by WriteModuleInfo.
1022  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1023    if (!isa<GlobalValue>(Vals[i].first)) {
1024      WriteConstants(i, Vals.size(), VE, Stream, true);
1025      return;
1026    }
1027  }
1028}
1029
1030/// PushValueAndType - The file has to encode both the value and type id for
1031/// many values, because we need to know what type to create for forward
1032/// references.  However, most operands are not forward references, so this type
1033/// field is not needed.
1034///
1035/// This function adds V's value ID to Vals.  If the value ID is higher than the
1036/// instruction ID, then it is a forward reference, and it also includes the
1037/// type ID.
1038static bool PushValueAndType(const Value *V, unsigned InstID,
1039                             SmallVector<unsigned, 64> &Vals,
1040                             ValueEnumerator &VE) {
1041  unsigned ValID = VE.getValueID(V);
1042  Vals.push_back(ValID);
1043  if (ValID >= InstID) {
1044    Vals.push_back(VE.getTypeID(V->getType()));
1045    return true;
1046  }
1047  return false;
1048}
1049
1050/// WriteInstruction - Emit an instruction to the specified stream.
1051static void WriteInstruction(const Instruction &I, unsigned InstID,
1052                             ValueEnumerator &VE, BitstreamWriter &Stream,
1053                             SmallVector<unsigned, 64> &Vals) {
1054  unsigned Code = 0;
1055  unsigned AbbrevToUse = 0;
1056  VE.setInstructionID(&I);
1057  switch (I.getOpcode()) {
1058  default:
1059    if (Instruction::isCast(I.getOpcode())) {
1060      Code = bitc::FUNC_CODE_INST_CAST;
1061      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1062        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1063      Vals.push_back(VE.getTypeID(I.getType()));
1064      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1065    } else {
1066      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1067      Code = bitc::FUNC_CODE_INST_BINOP;
1068      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1069        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1070      Vals.push_back(VE.getValueID(I.getOperand(1)));
1071      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1072      uint64_t Flags = GetOptimizationFlags(&I);
1073      if (Flags != 0) {
1074        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1075          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1076        Vals.push_back(Flags);
1077      }
1078    }
1079    break;
1080
1081  case Instruction::GetElementPtr:
1082    Code = bitc::FUNC_CODE_INST_GEP;
1083    if (cast<GEPOperator>(&I)->isInBounds())
1084      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1085    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1086      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1087    break;
1088  case Instruction::ExtractValue: {
1089    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1090    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1091    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1092    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1093      Vals.push_back(*i);
1094    break;
1095  }
1096  case Instruction::InsertValue: {
1097    Code = bitc::FUNC_CODE_INST_INSERTVAL;
1098    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1099    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1100    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1101    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1102      Vals.push_back(*i);
1103    break;
1104  }
1105  case Instruction::Select:
1106    Code = bitc::FUNC_CODE_INST_VSELECT;
1107    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1108    Vals.push_back(VE.getValueID(I.getOperand(2)));
1109    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1110    break;
1111  case Instruction::ExtractElement:
1112    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1113    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1114    Vals.push_back(VE.getValueID(I.getOperand(1)));
1115    break;
1116  case Instruction::InsertElement:
1117    Code = bitc::FUNC_CODE_INST_INSERTELT;
1118    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1119    Vals.push_back(VE.getValueID(I.getOperand(1)));
1120    Vals.push_back(VE.getValueID(I.getOperand(2)));
1121    break;
1122  case Instruction::ShuffleVector:
1123    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1124    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1125    Vals.push_back(VE.getValueID(I.getOperand(1)));
1126    Vals.push_back(VE.getValueID(I.getOperand(2)));
1127    break;
1128  case Instruction::ICmp:
1129  case Instruction::FCmp:
1130    // compare returning Int1Ty or vector of Int1Ty
1131    Code = bitc::FUNC_CODE_INST_CMP2;
1132    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1133    Vals.push_back(VE.getValueID(I.getOperand(1)));
1134    Vals.push_back(cast<CmpInst>(I).getPredicate());
1135    break;
1136
1137  case Instruction::Ret:
1138    {
1139      Code = bitc::FUNC_CODE_INST_RET;
1140      unsigned NumOperands = I.getNumOperands();
1141      if (NumOperands == 0)
1142        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1143      else if (NumOperands == 1) {
1144        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1145          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1146      } else {
1147        for (unsigned i = 0, e = NumOperands; i != e; ++i)
1148          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1149      }
1150    }
1151    break;
1152  case Instruction::Br:
1153    {
1154      Code = bitc::FUNC_CODE_INST_BR;
1155      BranchInst &II = cast<BranchInst>(I);
1156      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1157      if (II.isConditional()) {
1158        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1159        Vals.push_back(VE.getValueID(II.getCondition()));
1160      }
1161    }
1162    break;
1163  case Instruction::Switch:
1164    Code = bitc::FUNC_CODE_INST_SWITCH;
1165    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1166    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1167      Vals.push_back(VE.getValueID(I.getOperand(i)));
1168    break;
1169  case Instruction::IndirectBr:
1170    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1171    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1172    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1173      Vals.push_back(VE.getValueID(I.getOperand(i)));
1174    break;
1175
1176  case Instruction::Invoke: {
1177    const InvokeInst *II = cast<InvokeInst>(&I);
1178    const Value *Callee(II->getCalledValue());
1179    PointerType *PTy = cast<PointerType>(Callee->getType());
1180    FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1181    Code = bitc::FUNC_CODE_INST_INVOKE;
1182
1183    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1184    Vals.push_back(II->getCallingConv());
1185    Vals.push_back(VE.getValueID(II->getNormalDest()));
1186    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1187    PushValueAndType(Callee, InstID, Vals, VE);
1188
1189    // Emit value #'s for the fixed parameters.
1190    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1191      Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1192
1193    // Emit type/value pairs for varargs params.
1194    if (FTy->isVarArg()) {
1195      for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1196           i != e; ++i)
1197        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1198    }
1199    break;
1200  }
1201  case Instruction::Resume:
1202    Code = bitc::FUNC_CODE_INST_RESUME;
1203    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1204    break;
1205  case Instruction::Unwind:
1206    Code = bitc::FUNC_CODE_INST_UNWIND;
1207    break;
1208  case Instruction::Unreachable:
1209    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1210    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1211    break;
1212
1213  case Instruction::PHI: {
1214    const PHINode &PN = cast<PHINode>(I);
1215    Code = bitc::FUNC_CODE_INST_PHI;
1216    Vals.push_back(VE.getTypeID(PN.getType()));
1217    for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1218      Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1219      Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1220    }
1221    break;
1222  }
1223
1224  case Instruction::LandingPad: {
1225    const LandingPadInst &LP = cast<LandingPadInst>(I);
1226    Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1227    Vals.push_back(VE.getTypeID(LP.getType()));
1228    PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1229    Vals.push_back(LP.isCleanup());
1230    Vals.push_back(LP.getNumClauses());
1231    for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1232      if (LP.isCatch(I))
1233        Vals.push_back(LandingPadInst::Catch);
1234      else
1235        Vals.push_back(LandingPadInst::Filter);
1236      PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1237    }
1238    break;
1239  }
1240
1241  case Instruction::Alloca:
1242    Code = bitc::FUNC_CODE_INST_ALLOCA;
1243    Vals.push_back(VE.getTypeID(I.getType()));
1244    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1245    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1246    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1247    break;
1248
1249  case Instruction::Load:
1250    if (cast<LoadInst>(I).isAtomic()) {
1251      Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1252      PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1253    } else {
1254      Code = bitc::FUNC_CODE_INST_LOAD;
1255      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1256        AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1257    }
1258    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1259    Vals.push_back(cast<LoadInst>(I).isVolatile());
1260    if (cast<LoadInst>(I).isAtomic()) {
1261      Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1262      Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1263    }
1264    break;
1265  case Instruction::Store:
1266    if (cast<StoreInst>(I).isAtomic())
1267      Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1268    else
1269      Code = bitc::FUNC_CODE_INST_STORE;
1270    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1271    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1272    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1273    Vals.push_back(cast<StoreInst>(I).isVolatile());
1274    if (cast<StoreInst>(I).isAtomic()) {
1275      Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1276      Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1277    }
1278    break;
1279  case Instruction::AtomicCmpXchg:
1280    Code = bitc::FUNC_CODE_INST_CMPXCHG;
1281    PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1282    Vals.push_back(VE.getValueID(I.getOperand(1)));       // cmp.
1283    Vals.push_back(VE.getValueID(I.getOperand(2)));       // newval.
1284    Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1285    Vals.push_back(GetEncodedOrdering(
1286                     cast<AtomicCmpXchgInst>(I).getOrdering()));
1287    Vals.push_back(GetEncodedSynchScope(
1288                     cast<AtomicCmpXchgInst>(I).getSynchScope()));
1289    break;
1290  case Instruction::AtomicRMW:
1291    Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1292    PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1293    Vals.push_back(VE.getValueID(I.getOperand(1)));       // val.
1294    Vals.push_back(GetEncodedRMWOperation(
1295                     cast<AtomicRMWInst>(I).getOperation()));
1296    Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1297    Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1298    Vals.push_back(GetEncodedSynchScope(
1299                     cast<AtomicRMWInst>(I).getSynchScope()));
1300    break;
1301  case Instruction::Fence:
1302    Code = bitc::FUNC_CODE_INST_FENCE;
1303    Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1304    Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1305    break;
1306  case Instruction::Call: {
1307    const CallInst &CI = cast<CallInst>(I);
1308    PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1309    FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1310
1311    Code = bitc::FUNC_CODE_INST_CALL;
1312
1313    Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1314    Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1315    PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1316
1317    // Emit value #'s for the fixed parameters.
1318    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1319      Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1320
1321    // Emit type/value pairs for varargs params.
1322    if (FTy->isVarArg()) {
1323      for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1324           i != e; ++i)
1325        PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1326    }
1327    break;
1328  }
1329  case Instruction::VAArg:
1330    Code = bitc::FUNC_CODE_INST_VAARG;
1331    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1332    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1333    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1334    break;
1335  }
1336
1337  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1338  Vals.clear();
1339}
1340
1341// Emit names for globals/functions etc.
1342static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1343                                  const ValueEnumerator &VE,
1344                                  BitstreamWriter &Stream) {
1345  if (VST.empty()) return;
1346  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1347
1348  // FIXME: Set up the abbrev, we know how many values there are!
1349  // FIXME: We know if the type names can use 7-bit ascii.
1350  SmallVector<unsigned, 64> NameVals;
1351
1352  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1353       SI != SE; ++SI) {
1354
1355    const ValueName &Name = *SI;
1356
1357    // Figure out the encoding to use for the name.
1358    bool is7Bit = true;
1359    bool isChar6 = true;
1360    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1361         C != E; ++C) {
1362      if (isChar6)
1363        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1364      if ((unsigned char)*C & 128) {
1365        is7Bit = false;
1366        break;  // don't bother scanning the rest.
1367      }
1368    }
1369
1370    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1371
1372    // VST_ENTRY:   [valueid, namechar x N]
1373    // VST_BBENTRY: [bbid, namechar x N]
1374    unsigned Code;
1375    if (isa<BasicBlock>(SI->getValue())) {
1376      Code = bitc::VST_CODE_BBENTRY;
1377      if (isChar6)
1378        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1379    } else {
1380      Code = bitc::VST_CODE_ENTRY;
1381      if (isChar6)
1382        AbbrevToUse = VST_ENTRY_6_ABBREV;
1383      else if (is7Bit)
1384        AbbrevToUse = VST_ENTRY_7_ABBREV;
1385    }
1386
1387    NameVals.push_back(VE.getValueID(SI->getValue()));
1388    for (const char *P = Name.getKeyData(),
1389         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1390      NameVals.push_back((unsigned char)*P);
1391
1392    // Emit the finished record.
1393    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1394    NameVals.clear();
1395  }
1396  Stream.ExitBlock();
1397}
1398
1399/// WriteFunction - Emit a function body to the module stream.
1400static void WriteFunction(const Function &F, ValueEnumerator &VE,
1401                          BitstreamWriter &Stream) {
1402  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1403  VE.incorporateFunction(F);
1404
1405  SmallVector<unsigned, 64> Vals;
1406
1407  // Emit the number of basic blocks, so the reader can create them ahead of
1408  // time.
1409  Vals.push_back(VE.getBasicBlocks().size());
1410  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1411  Vals.clear();
1412
1413  // If there are function-local constants, emit them now.
1414  unsigned CstStart, CstEnd;
1415  VE.getFunctionConstantRange(CstStart, CstEnd);
1416  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1417
1418  // If there is function-local metadata, emit it now.
1419  WriteFunctionLocalMetadata(F, VE, Stream);
1420
1421  // Keep a running idea of what the instruction ID is.
1422  unsigned InstID = CstEnd;
1423
1424  bool NeedsMetadataAttachment = false;
1425
1426  DebugLoc LastDL;
1427
1428  // Finally, emit all the instructions, in order.
1429  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1430    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1431         I != E; ++I) {
1432      WriteInstruction(*I, InstID, VE, Stream, Vals);
1433
1434      if (!I->getType()->isVoidTy())
1435        ++InstID;
1436
1437      // If the instruction has metadata, write a metadata attachment later.
1438      NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1439
1440      // If the instruction has a debug location, emit it.
1441      DebugLoc DL = I->getDebugLoc();
1442      if (DL.isUnknown()) {
1443        // nothing todo.
1444      } else if (DL == LastDL) {
1445        // Just repeat the same debug loc as last time.
1446        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1447      } else {
1448        MDNode *Scope, *IA;
1449        DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1450
1451        Vals.push_back(DL.getLine());
1452        Vals.push_back(DL.getCol());
1453        Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1454        Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1455        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1456        Vals.clear();
1457
1458        LastDL = DL;
1459      }
1460    }
1461
1462  // Emit names for all the instructions etc.
1463  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1464
1465  if (NeedsMetadataAttachment)
1466    WriteMetadataAttachment(F, VE, Stream);
1467  VE.purgeFunction();
1468  Stream.ExitBlock();
1469}
1470
1471// Emit blockinfo, which defines the standard abbreviations etc.
1472static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1473  // We only want to emit block info records for blocks that have multiple
1474  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1475  // blocks can defined their abbrevs inline.
1476  Stream.EnterBlockInfoBlock(2);
1477
1478  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1479    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1480    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1481    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1482    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1483    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1484    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1485                                   Abbv) != VST_ENTRY_8_ABBREV)
1486      llvm_unreachable("Unexpected abbrev ordering!");
1487  }
1488
1489  { // 7-bit fixed width VST_ENTRY strings.
1490    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1491    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1492    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1493    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1494    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1495    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1496                                   Abbv) != VST_ENTRY_7_ABBREV)
1497      llvm_unreachable("Unexpected abbrev ordering!");
1498  }
1499  { // 6-bit char6 VST_ENTRY strings.
1500    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1501    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1502    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1503    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1504    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1505    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1506                                   Abbv) != VST_ENTRY_6_ABBREV)
1507      llvm_unreachable("Unexpected abbrev ordering!");
1508  }
1509  { // 6-bit char6 VST_BBENTRY strings.
1510    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1511    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1512    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1513    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1514    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1515    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1516                                   Abbv) != VST_BBENTRY_6_ABBREV)
1517      llvm_unreachable("Unexpected abbrev ordering!");
1518  }
1519
1520
1521
1522  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1523    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1524    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1525    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1526                              Log2_32_Ceil(VE.getTypes().size()+1)));
1527    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1528                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1529      llvm_unreachable("Unexpected abbrev ordering!");
1530  }
1531
1532  { // INTEGER abbrev for CONSTANTS_BLOCK.
1533    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1534    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1535    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1536    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1537                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1538      llvm_unreachable("Unexpected abbrev ordering!");
1539  }
1540
1541  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1542    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1543    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1544    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1545    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1546                              Log2_32_Ceil(VE.getTypes().size()+1)));
1547    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1548
1549    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1550                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1551      llvm_unreachable("Unexpected abbrev ordering!");
1552  }
1553  { // NULL abbrev for CONSTANTS_BLOCK.
1554    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1555    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1556    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1557                                   Abbv) != CONSTANTS_NULL_Abbrev)
1558      llvm_unreachable("Unexpected abbrev ordering!");
1559  }
1560
1561  // FIXME: This should only use space for first class types!
1562
1563  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1564    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1565    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1566    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1567    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1568    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1569    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1570                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1571      llvm_unreachable("Unexpected abbrev ordering!");
1572  }
1573  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1574    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1575    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1576    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1577    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1578    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1579    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1580                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1581      llvm_unreachable("Unexpected abbrev ordering!");
1582  }
1583  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1584    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1585    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1586    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1587    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1588    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1589    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1590    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1591                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1592      llvm_unreachable("Unexpected abbrev ordering!");
1593  }
1594  { // INST_CAST abbrev for FUNCTION_BLOCK.
1595    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1596    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1597    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1598    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1599                              Log2_32_Ceil(VE.getTypes().size()+1)));
1600    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1601    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1602                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1603      llvm_unreachable("Unexpected abbrev ordering!");
1604  }
1605
1606  { // INST_RET abbrev for FUNCTION_BLOCK.
1607    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1608    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1609    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1610                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1611      llvm_unreachable("Unexpected abbrev ordering!");
1612  }
1613  { // INST_RET abbrev for FUNCTION_BLOCK.
1614    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1615    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1616    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1617    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1618                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1619      llvm_unreachable("Unexpected abbrev ordering!");
1620  }
1621  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1622    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1623    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1624    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1625                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1626      llvm_unreachable("Unexpected abbrev ordering!");
1627  }
1628
1629  Stream.ExitBlock();
1630}
1631
1632// Sort the Users based on the order in which the reader parses the bitcode
1633// file.
1634static bool bitcodereader_order(const User *lhs, const User *rhs) {
1635  // TODO: Implement.
1636  return true;
1637}
1638
1639static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1640                         BitstreamWriter &Stream) {
1641
1642  // One or zero uses can't get out of order.
1643  if (V->use_empty() || V->hasNUses(1))
1644    return;
1645
1646  // Make a copy of the in-memory use-list for sorting.
1647  unsigned UseListSize = std::distance(V->use_begin(), V->use_end());
1648  SmallVector<const User*, 8> UseList;
1649  UseList.reserve(UseListSize);
1650  for (Value::const_use_iterator I = V->use_begin(), E = V->use_end();
1651       I != E; ++I) {
1652    const User *U = *I;
1653    UseList.push_back(U);
1654  }
1655
1656  // Sort the copy based on the order read by the BitcodeReader.
1657  std::sort(UseList.begin(), UseList.end(), bitcodereader_order);
1658
1659  // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1660  // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1661
1662  // TODO: Emit the USELIST_CODE_ENTRYs.
1663}
1664
1665static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1666                                 BitstreamWriter &Stream) {
1667  VE.incorporateFunction(*F);
1668
1669  for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1670       AI != AE; ++AI)
1671    WriteUseList(AI, VE, Stream);
1672  for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1673       ++BB) {
1674    WriteUseList(BB, VE, Stream);
1675    for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1676         ++II) {
1677      WriteUseList(II, VE, Stream);
1678      for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1679           OI != E; ++OI) {
1680        if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1681            isa<InlineAsm>(*OI))
1682          WriteUseList(*OI, VE, Stream);
1683      }
1684    }
1685  }
1686  VE.purgeFunction();
1687}
1688
1689// Emit use-lists.
1690static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1691                                BitstreamWriter &Stream) {
1692  Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1693
1694  // XXX: this modifies the module, but in a way that should never change the
1695  // behavior of any pass or codegen in LLVM. The problem is that GVs may
1696  // contain entries in the use_list that do not exist in the Module and are
1697  // not stored in the .bc file.
1698  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1699       I != E; ++I)
1700    I->removeDeadConstantUsers();
1701
1702  // Write the global variables.
1703  for (Module::const_global_iterator GI = M->global_begin(),
1704         GE = M->global_end(); GI != GE; ++GI) {
1705    WriteUseList(GI, VE, Stream);
1706
1707    // Write the global variable initializers.
1708    if (GI->hasInitializer())
1709      WriteUseList(GI->getInitializer(), VE, Stream);
1710  }
1711
1712  // Write the functions.
1713  for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1714    WriteUseList(FI, VE, Stream);
1715    if (!FI->isDeclaration())
1716      WriteFunctionUseList(FI, VE, Stream);
1717  }
1718
1719  // Write the aliases.
1720  for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1721       AI != AE; ++AI) {
1722    WriteUseList(AI, VE, Stream);
1723    WriteUseList(AI->getAliasee(), VE, Stream);
1724  }
1725
1726  Stream.ExitBlock();
1727}
1728
1729/// WriteModule - Emit the specified module to the bitstream.
1730static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1731  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1732
1733  // Emit the version number if it is non-zero.
1734  if (CurVersion) {
1735    SmallVector<unsigned, 1> Vals;
1736    Vals.push_back(CurVersion);
1737    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1738  }
1739
1740  // Analyze the module, enumerating globals, functions, etc.
1741  ValueEnumerator VE(M);
1742
1743  // Emit blockinfo, which defines the standard abbreviations etc.
1744  WriteBlockInfo(VE, Stream);
1745
1746  // Emit information about parameter attributes.
1747  WriteAttributeTable(VE, Stream);
1748
1749  // Emit information describing all of the types in the module.
1750  WriteTypeTable(VE, Stream);
1751
1752  // Emit top-level description of module, including target triple, inline asm,
1753  // descriptors for global variables, and function prototype info.
1754  WriteModuleInfo(M, VE, Stream);
1755
1756  // Emit constants.
1757  WriteModuleConstants(VE, Stream);
1758
1759  // Emit metadata.
1760  WriteModuleMetadata(M, VE, Stream);
1761
1762  // Emit function bodies.
1763  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1764    if (!F->isDeclaration())
1765      WriteFunction(*F, VE, Stream);
1766
1767  // Emit metadata.
1768  WriteModuleMetadataStore(M, Stream);
1769
1770  // Emit names for globals/functions etc.
1771  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1772
1773  // Emit use-lists.
1774  if (EnablePreserveUseListOrdering)
1775    WriteModuleUseLists(M, VE, Stream);
1776
1777  Stream.ExitBlock();
1778}
1779
1780/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1781/// header and trailer to make it compatible with the system archiver.  To do
1782/// this we emit the following header, and then emit a trailer that pads the
1783/// file out to be a multiple of 16 bytes.
1784///
1785/// struct bc_header {
1786///   uint32_t Magic;         // 0x0B17C0DE
1787///   uint32_t Version;       // Version, currently always 0.
1788///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1789///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1790///   uint32_t CPUType;       // CPU specifier.
1791///   ... potentially more later ...
1792/// };
1793enum {
1794  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1795  DarwinBCHeaderSize = 5*4
1796};
1797
1798static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
1799  unsigned CPUType = ~0U;
1800
1801  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1802  // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1803  // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1804  // specific constants here because they are implicitly part of the Darwin ABI.
1805  enum {
1806    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1807    DARWIN_CPU_TYPE_X86        = 7,
1808    DARWIN_CPU_TYPE_ARM        = 12,
1809    DARWIN_CPU_TYPE_POWERPC    = 18
1810  };
1811
1812  Triple::ArchType Arch = TT.getArch();
1813  if (Arch == Triple::x86_64)
1814    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1815  else if (Arch == Triple::x86)
1816    CPUType = DARWIN_CPU_TYPE_X86;
1817  else if (Arch == Triple::ppc)
1818    CPUType = DARWIN_CPU_TYPE_POWERPC;
1819  else if (Arch == Triple::ppc64)
1820    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1821  else if (Arch == Triple::arm || Arch == Triple::thumb)
1822    CPUType = DARWIN_CPU_TYPE_ARM;
1823
1824  // Traditional Bitcode starts after header.
1825  unsigned BCOffset = DarwinBCHeaderSize;
1826
1827  Stream.Emit(0x0B17C0DE, 32);
1828  Stream.Emit(0         , 32);  // Version.
1829  Stream.Emit(BCOffset  , 32);
1830  Stream.Emit(0         , 32);  // Filled in later.
1831  Stream.Emit(CPUType   , 32);
1832}
1833
1834/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1835/// finalize the header.
1836static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1837  // Update the size field in the header.
1838  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1839
1840  // If the file is not a multiple of 16 bytes, insert dummy padding.
1841  while (BufferSize & 15) {
1842    Stream.Emit(0, 8);
1843    ++BufferSize;
1844  }
1845}
1846
1847
1848/// WriteBitcodeToFile - Write the specified module to the specified output
1849/// stream.
1850void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1851  std::vector<unsigned char> Buffer;
1852  BitstreamWriter Stream(Buffer);
1853
1854  Buffer.reserve(256*1024);
1855
1856  WriteBitcodeToStream( M, Stream );
1857
1858  // Write the generated bitstream to "Out".
1859  Out.write((char*)&Buffer.front(), Buffer.size());
1860}
1861
1862/// WriteBitcodeToStream - Write the specified module to the specified output
1863/// stream.
1864void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1865  // If this is darwin or another generic macho target, emit a file header and
1866  // trailer if needed.
1867  Triple TT(M->getTargetTriple());
1868  if (TT.isOSDarwin())
1869    EmitDarwinBCHeader(Stream, TT);
1870
1871  // Emit the file header.
1872  Stream.Emit((unsigned)'B', 8);
1873  Stream.Emit((unsigned)'C', 8);
1874  Stream.Emit(0x0, 4);
1875  Stream.Emit(0xC, 4);
1876  Stream.Emit(0xE, 4);
1877  Stream.Emit(0xD, 4);
1878
1879  // Emit the module.
1880  WriteModule(M, Stream);
1881
1882  if (TT.isOSDarwin())
1883    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1884}
1885