BitcodeWriter.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
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 "ValueEnumerator.h"
16#include "llvm/ADT/Triple.h"
17#include "llvm/Bitcode/BitstreamWriter.h"
18#include "llvm/Bitcode/LLVMBitCodes.h"
19#include "llvm/IR/Constants.h"
20#include "llvm/IR/DerivedTypes.h"
21#include "llvm/IR/InlineAsm.h"
22#include "llvm/IR/Instructions.h"
23#include "llvm/IR/Module.h"
24#include "llvm/IR/Operator.h"
25#include "llvm/IR/ValueSymbolTable.h"
26#include "llvm/Support/CommandLine.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/MathExtras.h"
29#include "llvm/Support/Program.h"
30#include "llvm/Support/raw_ostream.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  // VALUE_SYMTAB_BLOCK abbrev id's.
45  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
46  VST_ENTRY_7_ABBREV,
47  VST_ENTRY_6_ABBREV,
48  VST_BBENTRY_6_ABBREV,
49
50  // CONSTANTS_BLOCK abbrev id's.
51  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
52  CONSTANTS_INTEGER_ABBREV,
53  CONSTANTS_CE_CAST_Abbrev,
54  CONSTANTS_NULL_Abbrev,
55
56  // FUNCTION_BLOCK abbrev id's.
57  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
58  FUNCTION_INST_BINOP_ABBREV,
59  FUNCTION_INST_BINOP_FLAGS_ABBREV,
60  FUNCTION_INST_CAST_ABBREV,
61  FUNCTION_INST_RET_VOID_ABBREV,
62  FUNCTION_INST_RET_VAL_ABBREV,
63  FUNCTION_INST_UNREACHABLE_ABBREV
64};
65
66static unsigned GetEncodedCastOpcode(unsigned Opcode) {
67  switch (Opcode) {
68  default: llvm_unreachable("Unknown cast instruction!");
69  case Instruction::Trunc   : return bitc::CAST_TRUNC;
70  case Instruction::ZExt    : return bitc::CAST_ZEXT;
71  case Instruction::SExt    : return bitc::CAST_SEXT;
72  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
73  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
74  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
75  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
76  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
77  case Instruction::FPExt   : return bitc::CAST_FPEXT;
78  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
79  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
80  case Instruction::BitCast : return bitc::CAST_BITCAST;
81  case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
82  }
83}
84
85static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
86  switch (Opcode) {
87  default: llvm_unreachable("Unknown binary instruction!");
88  case Instruction::Add:
89  case Instruction::FAdd: return bitc::BINOP_ADD;
90  case Instruction::Sub:
91  case Instruction::FSub: return bitc::BINOP_SUB;
92  case Instruction::Mul:
93  case Instruction::FMul: return bitc::BINOP_MUL;
94  case Instruction::UDiv: return bitc::BINOP_UDIV;
95  case Instruction::FDiv:
96  case Instruction::SDiv: return bitc::BINOP_SDIV;
97  case Instruction::URem: return bitc::BINOP_UREM;
98  case Instruction::FRem:
99  case Instruction::SRem: return bitc::BINOP_SREM;
100  case Instruction::Shl:  return bitc::BINOP_SHL;
101  case Instruction::LShr: return bitc::BINOP_LSHR;
102  case Instruction::AShr: return bitc::BINOP_ASHR;
103  case Instruction::And:  return bitc::BINOP_AND;
104  case Instruction::Or:   return bitc::BINOP_OR;
105  case Instruction::Xor:  return bitc::BINOP_XOR;
106  }
107}
108
109static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
110  switch (Op) {
111  default: llvm_unreachable("Unknown RMW operation!");
112  case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
113  case AtomicRMWInst::Add: return bitc::RMW_ADD;
114  case AtomicRMWInst::Sub: return bitc::RMW_SUB;
115  case AtomicRMWInst::And: return bitc::RMW_AND;
116  case AtomicRMWInst::Nand: return bitc::RMW_NAND;
117  case AtomicRMWInst::Or: return bitc::RMW_OR;
118  case AtomicRMWInst::Xor: return bitc::RMW_XOR;
119  case AtomicRMWInst::Max: return bitc::RMW_MAX;
120  case AtomicRMWInst::Min: return bitc::RMW_MIN;
121  case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
122  case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
123  }
124}
125
126static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
127  switch (Ordering) {
128  case NotAtomic: return bitc::ORDERING_NOTATOMIC;
129  case Unordered: return bitc::ORDERING_UNORDERED;
130  case Monotonic: return bitc::ORDERING_MONOTONIC;
131  case Acquire: return bitc::ORDERING_ACQUIRE;
132  case Release: return bitc::ORDERING_RELEASE;
133  case AcquireRelease: return bitc::ORDERING_ACQREL;
134  case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
135  }
136  llvm_unreachable("Invalid ordering");
137}
138
139static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
140  switch (SynchScope) {
141  case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
142  case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
143  }
144  llvm_unreachable("Invalid synch scope");
145}
146
147static void WriteStringRecord(unsigned Code, StringRef Str,
148                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
149  SmallVector<unsigned, 64> Vals;
150
151  // Code: [strchar x N]
152  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
153    if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
154      AbbrevToUse = 0;
155    Vals.push_back(Str[i]);
156  }
157
158  // Emit the finished record.
159  Stream.EmitRecord(Code, Vals, AbbrevToUse);
160}
161
162static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
163  switch (Kind) {
164  case Attribute::Alignment:
165    return bitc::ATTR_KIND_ALIGNMENT;
166  case Attribute::AlwaysInline:
167    return bitc::ATTR_KIND_ALWAYS_INLINE;
168  case Attribute::Builtin:
169    return bitc::ATTR_KIND_BUILTIN;
170  case Attribute::ByVal:
171    return bitc::ATTR_KIND_BY_VAL;
172  case Attribute::InAlloca:
173    return bitc::ATTR_KIND_IN_ALLOCA;
174  case Attribute::Cold:
175    return bitc::ATTR_KIND_COLD;
176  case Attribute::InlineHint:
177    return bitc::ATTR_KIND_INLINE_HINT;
178  case Attribute::InReg:
179    return bitc::ATTR_KIND_IN_REG;
180  case Attribute::MinSize:
181    return bitc::ATTR_KIND_MIN_SIZE;
182  case Attribute::Naked:
183    return bitc::ATTR_KIND_NAKED;
184  case Attribute::Nest:
185    return bitc::ATTR_KIND_NEST;
186  case Attribute::NoAlias:
187    return bitc::ATTR_KIND_NO_ALIAS;
188  case Attribute::NoBuiltin:
189    return bitc::ATTR_KIND_NO_BUILTIN;
190  case Attribute::NoCapture:
191    return bitc::ATTR_KIND_NO_CAPTURE;
192  case Attribute::NoDuplicate:
193    return bitc::ATTR_KIND_NO_DUPLICATE;
194  case Attribute::NoImplicitFloat:
195    return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
196  case Attribute::NoInline:
197    return bitc::ATTR_KIND_NO_INLINE;
198  case Attribute::NonLazyBind:
199    return bitc::ATTR_KIND_NON_LAZY_BIND;
200  case Attribute::NoRedZone:
201    return bitc::ATTR_KIND_NO_RED_ZONE;
202  case Attribute::NoReturn:
203    return bitc::ATTR_KIND_NO_RETURN;
204  case Attribute::NoUnwind:
205    return bitc::ATTR_KIND_NO_UNWIND;
206  case Attribute::OptimizeForSize:
207    return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
208  case Attribute::OptimizeNone:
209    return bitc::ATTR_KIND_OPTIMIZE_NONE;
210  case Attribute::ReadNone:
211    return bitc::ATTR_KIND_READ_NONE;
212  case Attribute::ReadOnly:
213    return bitc::ATTR_KIND_READ_ONLY;
214  case Attribute::Returned:
215    return bitc::ATTR_KIND_RETURNED;
216  case Attribute::ReturnsTwice:
217    return bitc::ATTR_KIND_RETURNS_TWICE;
218  case Attribute::SExt:
219    return bitc::ATTR_KIND_S_EXT;
220  case Attribute::StackAlignment:
221    return bitc::ATTR_KIND_STACK_ALIGNMENT;
222  case Attribute::StackProtect:
223    return bitc::ATTR_KIND_STACK_PROTECT;
224  case Attribute::StackProtectReq:
225    return bitc::ATTR_KIND_STACK_PROTECT_REQ;
226  case Attribute::StackProtectStrong:
227    return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
228  case Attribute::StructRet:
229    return bitc::ATTR_KIND_STRUCT_RET;
230  case Attribute::SanitizeAddress:
231    return bitc::ATTR_KIND_SANITIZE_ADDRESS;
232  case Attribute::SanitizeThread:
233    return bitc::ATTR_KIND_SANITIZE_THREAD;
234  case Attribute::SanitizeMemory:
235    return bitc::ATTR_KIND_SANITIZE_MEMORY;
236  case Attribute::UWTable:
237    return bitc::ATTR_KIND_UW_TABLE;
238  case Attribute::ZExt:
239    return bitc::ATTR_KIND_Z_EXT;
240  case Attribute::EndAttrKinds:
241    llvm_unreachable("Can not encode end-attribute kinds marker.");
242  case Attribute::None:
243    llvm_unreachable("Can not encode none-attribute.");
244  }
245
246  llvm_unreachable("Trying to encode unknown attribute");
247}
248
249static void WriteAttributeGroupTable(const ValueEnumerator &VE,
250                                     BitstreamWriter &Stream) {
251  const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
252  if (AttrGrps.empty()) return;
253
254  Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
255
256  SmallVector<uint64_t, 64> Record;
257  for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
258    AttributeSet AS = AttrGrps[i];
259    for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
260      AttributeSet A = AS.getSlotAttributes(i);
261
262      Record.push_back(VE.getAttributeGroupID(A));
263      Record.push_back(AS.getSlotIndex(i));
264
265      for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
266           I != E; ++I) {
267        Attribute Attr = *I;
268        if (Attr.isEnumAttribute()) {
269          Record.push_back(0);
270          Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
271        } else if (Attr.isAlignAttribute()) {
272          Record.push_back(1);
273          Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
274          Record.push_back(Attr.getValueAsInt());
275        } else {
276          StringRef Kind = Attr.getKindAsString();
277          StringRef Val = Attr.getValueAsString();
278
279          Record.push_back(Val.empty() ? 3 : 4);
280          Record.append(Kind.begin(), Kind.end());
281          Record.push_back(0);
282          if (!Val.empty()) {
283            Record.append(Val.begin(), Val.end());
284            Record.push_back(0);
285          }
286        }
287      }
288
289      Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
290      Record.clear();
291    }
292  }
293
294  Stream.ExitBlock();
295}
296
297static void WriteAttributeTable(const ValueEnumerator &VE,
298                                BitstreamWriter &Stream) {
299  const std::vector<AttributeSet> &Attrs = VE.getAttributes();
300  if (Attrs.empty()) return;
301
302  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
303
304  SmallVector<uint64_t, 64> Record;
305  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
306    const AttributeSet &A = Attrs[i];
307    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
308      Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
309
310    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
311    Record.clear();
312  }
313
314  Stream.ExitBlock();
315}
316
317/// WriteTypeTable - Write out the type table for a module.
318static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
319  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
320
321  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
322  SmallVector<uint64_t, 64> TypeVals;
323
324  uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
325
326  // Abbrev for TYPE_CODE_POINTER.
327  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
328  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
329  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
330  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
331  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
332
333  // Abbrev for TYPE_CODE_FUNCTION.
334  Abbv = new BitCodeAbbrev();
335  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
336  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
337  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
338  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
339
340  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
341
342  // Abbrev for TYPE_CODE_STRUCT_ANON.
343  Abbv = new BitCodeAbbrev();
344  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
345  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
346  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
347  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
348
349  unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
350
351  // Abbrev for TYPE_CODE_STRUCT_NAME.
352  Abbv = new BitCodeAbbrev();
353  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
354  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
355  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
356  unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
357
358  // Abbrev for TYPE_CODE_STRUCT_NAMED.
359  Abbv = new BitCodeAbbrev();
360  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
361  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
362  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
363  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
364
365  unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
366
367  // Abbrev for TYPE_CODE_ARRAY.
368  Abbv = new BitCodeAbbrev();
369  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
370  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
371  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
372
373  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
374
375  // Emit an entry count so the reader can reserve space.
376  TypeVals.push_back(TypeList.size());
377  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
378  TypeVals.clear();
379
380  // Loop over all of the types, emitting each in turn.
381  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
382    Type *T = TypeList[i];
383    int AbbrevToUse = 0;
384    unsigned Code = 0;
385
386    switch (T->getTypeID()) {
387    case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
388    case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
389    case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
390    case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
391    case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
392    case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
393    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
394    case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
395    case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
396    case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
397    case Type::IntegerTyID:
398      // INTEGER: [width]
399      Code = bitc::TYPE_CODE_INTEGER;
400      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
401      break;
402    case Type::PointerTyID: {
403      PointerType *PTy = cast<PointerType>(T);
404      // POINTER: [pointee type, address space]
405      Code = bitc::TYPE_CODE_POINTER;
406      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
407      unsigned AddressSpace = PTy->getAddressSpace();
408      TypeVals.push_back(AddressSpace);
409      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
410      break;
411    }
412    case Type::FunctionTyID: {
413      FunctionType *FT = cast<FunctionType>(T);
414      // FUNCTION: [isvararg, retty, paramty x N]
415      Code = bitc::TYPE_CODE_FUNCTION;
416      TypeVals.push_back(FT->isVarArg());
417      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
418      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
419        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
420      AbbrevToUse = FunctionAbbrev;
421      break;
422    }
423    case Type::StructTyID: {
424      StructType *ST = cast<StructType>(T);
425      // STRUCT: [ispacked, eltty x N]
426      TypeVals.push_back(ST->isPacked());
427      // Output all of the element types.
428      for (StructType::element_iterator I = ST->element_begin(),
429           E = ST->element_end(); I != E; ++I)
430        TypeVals.push_back(VE.getTypeID(*I));
431
432      if (ST->isLiteral()) {
433        Code = bitc::TYPE_CODE_STRUCT_ANON;
434        AbbrevToUse = StructAnonAbbrev;
435      } else {
436        if (ST->isOpaque()) {
437          Code = bitc::TYPE_CODE_OPAQUE;
438        } else {
439          Code = bitc::TYPE_CODE_STRUCT_NAMED;
440          AbbrevToUse = StructNamedAbbrev;
441        }
442
443        // Emit the name if it is present.
444        if (!ST->getName().empty())
445          WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
446                            StructNameAbbrev, Stream);
447      }
448      break;
449    }
450    case Type::ArrayTyID: {
451      ArrayType *AT = cast<ArrayType>(T);
452      // ARRAY: [numelts, eltty]
453      Code = bitc::TYPE_CODE_ARRAY;
454      TypeVals.push_back(AT->getNumElements());
455      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
456      AbbrevToUse = ArrayAbbrev;
457      break;
458    }
459    case Type::VectorTyID: {
460      VectorType *VT = cast<VectorType>(T);
461      // VECTOR [numelts, eltty]
462      Code = bitc::TYPE_CODE_VECTOR;
463      TypeVals.push_back(VT->getNumElements());
464      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
465      break;
466    }
467    }
468
469    // Emit the finished record.
470    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
471    TypeVals.clear();
472  }
473
474  Stream.ExitBlock();
475}
476
477static unsigned getEncodedLinkage(const GlobalValue *GV) {
478  switch (GV->getLinkage()) {
479  case GlobalValue::ExternalLinkage:                 return 0;
480  case GlobalValue::WeakAnyLinkage:                  return 1;
481  case GlobalValue::AppendingLinkage:                return 2;
482  case GlobalValue::InternalLinkage:                 return 3;
483  case GlobalValue::LinkOnceAnyLinkage:              return 4;
484  case GlobalValue::ExternalWeakLinkage:             return 7;
485  case GlobalValue::CommonLinkage:                   return 8;
486  case GlobalValue::PrivateLinkage:                  return 9;
487  case GlobalValue::WeakODRLinkage:                  return 10;
488  case GlobalValue::LinkOnceODRLinkage:              return 11;
489  case GlobalValue::AvailableExternallyLinkage:      return 12;
490  }
491  llvm_unreachable("Invalid linkage");
492}
493
494static unsigned getEncodedVisibility(const GlobalValue *GV) {
495  switch (GV->getVisibility()) {
496  case GlobalValue::DefaultVisibility:   return 0;
497  case GlobalValue::HiddenVisibility:    return 1;
498  case GlobalValue::ProtectedVisibility: return 2;
499  }
500  llvm_unreachable("Invalid visibility");
501}
502
503static unsigned getEncodedDLLStorageClass(const GlobalValue *GV) {
504  switch (GV->getDLLStorageClass()) {
505  case GlobalValue::DefaultStorageClass:   return 0;
506  case GlobalValue::DLLImportStorageClass: return 1;
507  case GlobalValue::DLLExportStorageClass: return 2;
508  }
509  llvm_unreachable("Invalid DLL storage class");
510}
511
512static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
513  switch (GV->getThreadLocalMode()) {
514    case GlobalVariable::NotThreadLocal:         return 0;
515    case GlobalVariable::GeneralDynamicTLSModel: return 1;
516    case GlobalVariable::LocalDynamicTLSModel:   return 2;
517    case GlobalVariable::InitialExecTLSModel:    return 3;
518    case GlobalVariable::LocalExecTLSModel:      return 4;
519  }
520  llvm_unreachable("Invalid TLS model");
521}
522
523// Emit top-level description of module, including target triple, inline asm,
524// descriptors for global variables, and function prototype info.
525static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
526                            BitstreamWriter &Stream) {
527  // Emit various pieces of data attached to a module.
528  if (!M->getTargetTriple().empty())
529    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
530                      0/*TODO*/, Stream);
531  const std::string &DL = M->getDataLayoutStr();
532  if (!DL.empty())
533    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
534  if (!M->getModuleInlineAsm().empty())
535    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
536                      0/*TODO*/, Stream);
537
538  // Emit information about sections and GC, computing how many there are. Also
539  // compute the maximum alignment value.
540  std::map<std::string, unsigned> SectionMap;
541  std::map<std::string, unsigned> GCMap;
542  unsigned MaxAlignment = 0;
543  unsigned MaxGlobalType = 0;
544  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
545       GV != E; ++GV) {
546    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
547    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
548    if (GV->hasSection()) {
549      // Give section names unique ID's.
550      unsigned &Entry = SectionMap[GV->getSection()];
551      if (!Entry) {
552        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
553                          0/*TODO*/, Stream);
554        Entry = SectionMap.size();
555      }
556    }
557  }
558  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
559    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
560    if (F->hasSection()) {
561      // Give section names unique ID's.
562      unsigned &Entry = SectionMap[F->getSection()];
563      if (!Entry) {
564        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
565                          0/*TODO*/, Stream);
566        Entry = SectionMap.size();
567      }
568    }
569    if (F->hasGC()) {
570      // Same for GC names.
571      unsigned &Entry = GCMap[F->getGC()];
572      if (!Entry) {
573        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
574                          0/*TODO*/, Stream);
575        Entry = GCMap.size();
576      }
577    }
578  }
579
580  // Emit abbrev for globals, now that we know # sections and max alignment.
581  unsigned SimpleGVarAbbrev = 0;
582  if (!M->global_empty()) {
583    // Add an abbrev for common globals with no visibility or thread localness.
584    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
585    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
586    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
587                              Log2_32_Ceil(MaxGlobalType+1)));
588    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
589    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
590    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
591    if (MaxAlignment == 0)                                      // Alignment.
592      Abbv->Add(BitCodeAbbrevOp(0));
593    else {
594      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
595      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
596                               Log2_32_Ceil(MaxEncAlignment+1)));
597    }
598    if (SectionMap.empty())                                    // Section.
599      Abbv->Add(BitCodeAbbrevOp(0));
600    else
601      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
602                               Log2_32_Ceil(SectionMap.size()+1)));
603    // Don't bother emitting vis + thread local.
604    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
605  }
606
607  // Emit the global variable information.
608  SmallVector<unsigned, 64> Vals;
609  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
610       GV != E; ++GV) {
611    unsigned AbbrevToUse = 0;
612
613    // GLOBALVAR: [type, isconst, initid,
614    //             linkage, alignment, section, visibility, threadlocal,
615    //             unnamed_addr, externally_initialized, dllstorageclass]
616    Vals.push_back(VE.getTypeID(GV->getType()));
617    Vals.push_back(GV->isConstant());
618    Vals.push_back(GV->isDeclaration() ? 0 :
619                   (VE.getValueID(GV->getInitializer()) + 1));
620    Vals.push_back(getEncodedLinkage(GV));
621    Vals.push_back(Log2_32(GV->getAlignment())+1);
622    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
623    if (GV->isThreadLocal() ||
624        GV->getVisibility() != GlobalValue::DefaultVisibility ||
625        GV->hasUnnamedAddr() || GV->isExternallyInitialized() ||
626        GV->getDLLStorageClass() != GlobalValue::DefaultStorageClass) {
627      Vals.push_back(getEncodedVisibility(GV));
628      Vals.push_back(getEncodedThreadLocalMode(GV));
629      Vals.push_back(GV->hasUnnamedAddr());
630      Vals.push_back(GV->isExternallyInitialized());
631      Vals.push_back(getEncodedDLLStorageClass(GV));
632    } else {
633      AbbrevToUse = SimpleGVarAbbrev;
634    }
635
636    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
637    Vals.clear();
638  }
639
640  // Emit the function proto information.
641  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
642    // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
643    //             section, visibility, gc, unnamed_addr, prefix]
644    Vals.push_back(VE.getTypeID(F->getType()));
645    Vals.push_back(F->getCallingConv());
646    Vals.push_back(F->isDeclaration());
647    Vals.push_back(getEncodedLinkage(F));
648    Vals.push_back(VE.getAttributeID(F->getAttributes()));
649    Vals.push_back(Log2_32(F->getAlignment())+1);
650    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
651    Vals.push_back(getEncodedVisibility(F));
652    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
653    Vals.push_back(F->hasUnnamedAddr());
654    Vals.push_back(F->hasPrefixData() ? (VE.getValueID(F->getPrefixData()) + 1)
655                                      : 0);
656    Vals.push_back(getEncodedDLLStorageClass(F));
657
658    unsigned AbbrevToUse = 0;
659    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
660    Vals.clear();
661  }
662
663  // Emit the alias information.
664  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
665       AI != E; ++AI) {
666    // ALIAS: [alias type, aliasee val#, linkage, visibility]
667    Vals.push_back(VE.getTypeID(AI->getType()));
668    Vals.push_back(VE.getValueID(AI->getAliasee()));
669    Vals.push_back(getEncodedLinkage(AI));
670    Vals.push_back(getEncodedVisibility(AI));
671    Vals.push_back(getEncodedDLLStorageClass(AI));
672    unsigned AbbrevToUse = 0;
673    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
674    Vals.clear();
675  }
676}
677
678static uint64_t GetOptimizationFlags(const Value *V) {
679  uint64_t Flags = 0;
680
681  if (const OverflowingBinaryOperator *OBO =
682        dyn_cast<OverflowingBinaryOperator>(V)) {
683    if (OBO->hasNoSignedWrap())
684      Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
685    if (OBO->hasNoUnsignedWrap())
686      Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
687  } else if (const PossiblyExactOperator *PEO =
688               dyn_cast<PossiblyExactOperator>(V)) {
689    if (PEO->isExact())
690      Flags |= 1 << bitc::PEO_EXACT;
691  } else if (const FPMathOperator *FPMO =
692             dyn_cast<const FPMathOperator>(V)) {
693    if (FPMO->hasUnsafeAlgebra())
694      Flags |= FastMathFlags::UnsafeAlgebra;
695    if (FPMO->hasNoNaNs())
696      Flags |= FastMathFlags::NoNaNs;
697    if (FPMO->hasNoInfs())
698      Flags |= FastMathFlags::NoInfs;
699    if (FPMO->hasNoSignedZeros())
700      Flags |= FastMathFlags::NoSignedZeros;
701    if (FPMO->hasAllowReciprocal())
702      Flags |= FastMathFlags::AllowReciprocal;
703  }
704
705  return Flags;
706}
707
708static void WriteMDNode(const MDNode *N,
709                        const ValueEnumerator &VE,
710                        BitstreamWriter &Stream,
711                        SmallVectorImpl<uint64_t> &Record) {
712  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
713    if (N->getOperand(i)) {
714      Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
715      Record.push_back(VE.getValueID(N->getOperand(i)));
716    } else {
717      Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
718      Record.push_back(0);
719    }
720  }
721  unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
722                                           bitc::METADATA_NODE;
723  Stream.EmitRecord(MDCode, Record, 0);
724  Record.clear();
725}
726
727static void WriteModuleMetadata(const Module *M,
728                                const ValueEnumerator &VE,
729                                BitstreamWriter &Stream) {
730  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
731  bool StartedMetadataBlock = false;
732  unsigned MDSAbbrev = 0;
733  SmallVector<uint64_t, 64> Record;
734  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
735
736    if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
737      if (!N->isFunctionLocal() || !N->getFunction()) {
738        if (!StartedMetadataBlock) {
739          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
740          StartedMetadataBlock = true;
741        }
742        WriteMDNode(N, VE, Stream, Record);
743      }
744    } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
745      if (!StartedMetadataBlock)  {
746        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
747
748        // Abbrev for METADATA_STRING.
749        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
750        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
751        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
752        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
753        MDSAbbrev = Stream.EmitAbbrev(Abbv);
754        StartedMetadataBlock = true;
755      }
756
757      // Code: [strchar x N]
758      Record.append(MDS->begin(), MDS->end());
759
760      // Emit the finished record.
761      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
762      Record.clear();
763    }
764  }
765
766  // Write named metadata.
767  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
768       E = M->named_metadata_end(); I != E; ++I) {
769    const NamedMDNode *NMD = I;
770    if (!StartedMetadataBlock)  {
771      Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
772      StartedMetadataBlock = true;
773    }
774
775    // Write name.
776    StringRef Str = NMD->getName();
777    for (unsigned i = 0, e = Str.size(); i != e; ++i)
778      Record.push_back(Str[i]);
779    Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
780    Record.clear();
781
782    // Write named metadata operands.
783    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
784      Record.push_back(VE.getValueID(NMD->getOperand(i)));
785    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
786    Record.clear();
787  }
788
789  if (StartedMetadataBlock)
790    Stream.ExitBlock();
791}
792
793static void WriteFunctionLocalMetadata(const Function &F,
794                                       const ValueEnumerator &VE,
795                                       BitstreamWriter &Stream) {
796  bool StartedMetadataBlock = false;
797  SmallVector<uint64_t, 64> Record;
798  const SmallVectorImpl<const MDNode *> &Vals = VE.getFunctionLocalMDValues();
799  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
800    if (const MDNode *N = Vals[i])
801      if (N->isFunctionLocal() && N->getFunction() == &F) {
802        if (!StartedMetadataBlock) {
803          Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
804          StartedMetadataBlock = true;
805        }
806        WriteMDNode(N, VE, Stream, Record);
807      }
808
809  if (StartedMetadataBlock)
810    Stream.ExitBlock();
811}
812
813static void WriteMetadataAttachment(const Function &F,
814                                    const ValueEnumerator &VE,
815                                    BitstreamWriter &Stream) {
816  Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
817
818  SmallVector<uint64_t, 64> Record;
819
820  // Write metadata attachments
821  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
822  SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
823
824  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
825    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
826         I != E; ++I) {
827      MDs.clear();
828      I->getAllMetadataOtherThanDebugLoc(MDs);
829
830      // If no metadata, ignore instruction.
831      if (MDs.empty()) continue;
832
833      Record.push_back(VE.getInstructionID(I));
834
835      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
836        Record.push_back(MDs[i].first);
837        Record.push_back(VE.getValueID(MDs[i].second));
838      }
839      Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
840      Record.clear();
841    }
842
843  Stream.ExitBlock();
844}
845
846static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
847  SmallVector<uint64_t, 64> Record;
848
849  // Write metadata kinds
850  // METADATA_KIND - [n x [id, name]]
851  SmallVector<StringRef, 8> Names;
852  M->getMDKindNames(Names);
853
854  if (Names.empty()) return;
855
856  Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
857
858  for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
859    Record.push_back(MDKindID);
860    StringRef KName = Names[MDKindID];
861    Record.append(KName.begin(), KName.end());
862
863    Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
864    Record.clear();
865  }
866
867  Stream.ExitBlock();
868}
869
870static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
871  if ((int64_t)V >= 0)
872    Vals.push_back(V << 1);
873  else
874    Vals.push_back((-V << 1) | 1);
875}
876
877static void WriteConstants(unsigned FirstVal, unsigned LastVal,
878                           const ValueEnumerator &VE,
879                           BitstreamWriter &Stream, bool isGlobal) {
880  if (FirstVal == LastVal) return;
881
882  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
883
884  unsigned AggregateAbbrev = 0;
885  unsigned String8Abbrev = 0;
886  unsigned CString7Abbrev = 0;
887  unsigned CString6Abbrev = 0;
888  // If this is a constant pool for the module, emit module-specific abbrevs.
889  if (isGlobal) {
890    // Abbrev for CST_CODE_AGGREGATE.
891    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
892    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
893    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
894    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
895    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
896
897    // Abbrev for CST_CODE_STRING.
898    Abbv = new BitCodeAbbrev();
899    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
900    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
901    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
902    String8Abbrev = Stream.EmitAbbrev(Abbv);
903    // Abbrev for CST_CODE_CSTRING.
904    Abbv = new BitCodeAbbrev();
905    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
906    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
907    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
908    CString7Abbrev = Stream.EmitAbbrev(Abbv);
909    // Abbrev for CST_CODE_CSTRING.
910    Abbv = new BitCodeAbbrev();
911    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
912    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
913    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
914    CString6Abbrev = Stream.EmitAbbrev(Abbv);
915  }
916
917  SmallVector<uint64_t, 64> Record;
918
919  const ValueEnumerator::ValueList &Vals = VE.getValues();
920  Type *LastTy = 0;
921  for (unsigned i = FirstVal; i != LastVal; ++i) {
922    const Value *V = Vals[i].first;
923    // If we need to switch types, do so now.
924    if (V->getType() != LastTy) {
925      LastTy = V->getType();
926      Record.push_back(VE.getTypeID(LastTy));
927      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
928                        CONSTANTS_SETTYPE_ABBREV);
929      Record.clear();
930    }
931
932    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
933      Record.push_back(unsigned(IA->hasSideEffects()) |
934                       unsigned(IA->isAlignStack()) << 1 |
935                       unsigned(IA->getDialect()&1) << 2);
936
937      // Add the asm string.
938      const std::string &AsmStr = IA->getAsmString();
939      Record.push_back(AsmStr.size());
940      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
941        Record.push_back(AsmStr[i]);
942
943      // Add the constraint string.
944      const std::string &ConstraintStr = IA->getConstraintString();
945      Record.push_back(ConstraintStr.size());
946      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
947        Record.push_back(ConstraintStr[i]);
948      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
949      Record.clear();
950      continue;
951    }
952    const Constant *C = cast<Constant>(V);
953    unsigned Code = -1U;
954    unsigned AbbrevToUse = 0;
955    if (C->isNullValue()) {
956      Code = bitc::CST_CODE_NULL;
957    } else if (isa<UndefValue>(C)) {
958      Code = bitc::CST_CODE_UNDEF;
959    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
960      if (IV->getBitWidth() <= 64) {
961        uint64_t V = IV->getSExtValue();
962        emitSignedInt64(Record, V);
963        Code = bitc::CST_CODE_INTEGER;
964        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
965      } else {                             // Wide integers, > 64 bits in size.
966        // We have an arbitrary precision integer value to write whose
967        // bit width is > 64. However, in canonical unsigned integer
968        // format it is likely that the high bits are going to be zero.
969        // So, we only write the number of active words.
970        unsigned NWords = IV->getValue().getActiveWords();
971        const uint64_t *RawWords = IV->getValue().getRawData();
972        for (unsigned i = 0; i != NWords; ++i) {
973          emitSignedInt64(Record, RawWords[i]);
974        }
975        Code = bitc::CST_CODE_WIDE_INTEGER;
976      }
977    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
978      Code = bitc::CST_CODE_FLOAT;
979      Type *Ty = CFP->getType();
980      if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
981        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
982      } else if (Ty->isX86_FP80Ty()) {
983        // api needed to prevent premature destruction
984        // bits are not in the same order as a normal i80 APInt, compensate.
985        APInt api = CFP->getValueAPF().bitcastToAPInt();
986        const uint64_t *p = api.getRawData();
987        Record.push_back((p[1] << 48) | (p[0] >> 16));
988        Record.push_back(p[0] & 0xffffLL);
989      } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
990        APInt api = CFP->getValueAPF().bitcastToAPInt();
991        const uint64_t *p = api.getRawData();
992        Record.push_back(p[0]);
993        Record.push_back(p[1]);
994      } else {
995        assert (0 && "Unknown FP type!");
996      }
997    } else if (isa<ConstantDataSequential>(C) &&
998               cast<ConstantDataSequential>(C)->isString()) {
999      const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1000      // Emit constant strings specially.
1001      unsigned NumElts = Str->getNumElements();
1002      // If this is a null-terminated string, use the denser CSTRING encoding.
1003      if (Str->isCString()) {
1004        Code = bitc::CST_CODE_CSTRING;
1005        --NumElts;  // Don't encode the null, which isn't allowed by char6.
1006      } else {
1007        Code = bitc::CST_CODE_STRING;
1008        AbbrevToUse = String8Abbrev;
1009      }
1010      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1011      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1012      for (unsigned i = 0; i != NumElts; ++i) {
1013        unsigned char V = Str->getElementAsInteger(i);
1014        Record.push_back(V);
1015        isCStr7 &= (V & 128) == 0;
1016        if (isCStrChar6)
1017          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1018      }
1019
1020      if (isCStrChar6)
1021        AbbrevToUse = CString6Abbrev;
1022      else if (isCStr7)
1023        AbbrevToUse = CString7Abbrev;
1024    } else if (const ConstantDataSequential *CDS =
1025                  dyn_cast<ConstantDataSequential>(C)) {
1026      Code = bitc::CST_CODE_DATA;
1027      Type *EltTy = CDS->getType()->getElementType();
1028      if (isa<IntegerType>(EltTy)) {
1029        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1030          Record.push_back(CDS->getElementAsInteger(i));
1031      } else if (EltTy->isFloatTy()) {
1032        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1033          union { float F; uint32_t I; };
1034          F = CDS->getElementAsFloat(i);
1035          Record.push_back(I);
1036        }
1037      } else {
1038        assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1039        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1040          union { double F; uint64_t I; };
1041          F = CDS->getElementAsDouble(i);
1042          Record.push_back(I);
1043        }
1044      }
1045    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1046               isa<ConstantVector>(C)) {
1047      Code = bitc::CST_CODE_AGGREGATE;
1048      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1049        Record.push_back(VE.getValueID(C->getOperand(i)));
1050      AbbrevToUse = AggregateAbbrev;
1051    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1052      switch (CE->getOpcode()) {
1053      default:
1054        if (Instruction::isCast(CE->getOpcode())) {
1055          Code = bitc::CST_CODE_CE_CAST;
1056          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1057          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1058          Record.push_back(VE.getValueID(C->getOperand(0)));
1059          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1060        } else {
1061          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1062          Code = bitc::CST_CODE_CE_BINOP;
1063          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1064          Record.push_back(VE.getValueID(C->getOperand(0)));
1065          Record.push_back(VE.getValueID(C->getOperand(1)));
1066          uint64_t Flags = GetOptimizationFlags(CE);
1067          if (Flags != 0)
1068            Record.push_back(Flags);
1069        }
1070        break;
1071      case Instruction::GetElementPtr:
1072        Code = bitc::CST_CODE_CE_GEP;
1073        if (cast<GEPOperator>(C)->isInBounds())
1074          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1075        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1076          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1077          Record.push_back(VE.getValueID(C->getOperand(i)));
1078        }
1079        break;
1080      case Instruction::Select:
1081        Code = bitc::CST_CODE_CE_SELECT;
1082        Record.push_back(VE.getValueID(C->getOperand(0)));
1083        Record.push_back(VE.getValueID(C->getOperand(1)));
1084        Record.push_back(VE.getValueID(C->getOperand(2)));
1085        break;
1086      case Instruction::ExtractElement:
1087        Code = bitc::CST_CODE_CE_EXTRACTELT;
1088        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1089        Record.push_back(VE.getValueID(C->getOperand(0)));
1090        Record.push_back(VE.getValueID(C->getOperand(1)));
1091        break;
1092      case Instruction::InsertElement:
1093        Code = bitc::CST_CODE_CE_INSERTELT;
1094        Record.push_back(VE.getValueID(C->getOperand(0)));
1095        Record.push_back(VE.getValueID(C->getOperand(1)));
1096        Record.push_back(VE.getValueID(C->getOperand(2)));
1097        break;
1098      case Instruction::ShuffleVector:
1099        // If the return type and argument types are the same, this is a
1100        // standard shufflevector instruction.  If the types are different,
1101        // then the shuffle is widening or truncating the input vectors, and
1102        // the argument type must also be encoded.
1103        if (C->getType() == C->getOperand(0)->getType()) {
1104          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1105        } else {
1106          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1107          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1108        }
1109        Record.push_back(VE.getValueID(C->getOperand(0)));
1110        Record.push_back(VE.getValueID(C->getOperand(1)));
1111        Record.push_back(VE.getValueID(C->getOperand(2)));
1112        break;
1113      case Instruction::ICmp:
1114      case Instruction::FCmp:
1115        Code = bitc::CST_CODE_CE_CMP;
1116        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1117        Record.push_back(VE.getValueID(C->getOperand(0)));
1118        Record.push_back(VE.getValueID(C->getOperand(1)));
1119        Record.push_back(CE->getPredicate());
1120        break;
1121      }
1122    } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1123      Code = bitc::CST_CODE_BLOCKADDRESS;
1124      Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1125      Record.push_back(VE.getValueID(BA->getFunction()));
1126      Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1127    } else {
1128#ifndef NDEBUG
1129      C->dump();
1130#endif
1131      llvm_unreachable("Unknown constant!");
1132    }
1133    Stream.EmitRecord(Code, Record, AbbrevToUse);
1134    Record.clear();
1135  }
1136
1137  Stream.ExitBlock();
1138}
1139
1140static void WriteModuleConstants(const ValueEnumerator &VE,
1141                                 BitstreamWriter &Stream) {
1142  const ValueEnumerator::ValueList &Vals = VE.getValues();
1143
1144  // Find the first constant to emit, which is the first non-globalvalue value.
1145  // We know globalvalues have been emitted by WriteModuleInfo.
1146  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1147    if (!isa<GlobalValue>(Vals[i].first)) {
1148      WriteConstants(i, Vals.size(), VE, Stream, true);
1149      return;
1150    }
1151  }
1152}
1153
1154/// PushValueAndType - The file has to encode both the value and type id for
1155/// many values, because we need to know what type to create for forward
1156/// references.  However, most operands are not forward references, so this type
1157/// field is not needed.
1158///
1159/// This function adds V's value ID to Vals.  If the value ID is higher than the
1160/// instruction ID, then it is a forward reference, and it also includes the
1161/// type ID.  The value ID that is written is encoded relative to the InstID.
1162static bool PushValueAndType(const Value *V, unsigned InstID,
1163                             SmallVectorImpl<unsigned> &Vals,
1164                             ValueEnumerator &VE) {
1165  unsigned ValID = VE.getValueID(V);
1166  // Make encoding relative to the InstID.
1167  Vals.push_back(InstID - ValID);
1168  if (ValID >= InstID) {
1169    Vals.push_back(VE.getTypeID(V->getType()));
1170    return true;
1171  }
1172  return false;
1173}
1174
1175/// pushValue - Like PushValueAndType, but where the type of the value is
1176/// omitted (perhaps it was already encoded in an earlier operand).
1177static void pushValue(const Value *V, unsigned InstID,
1178                      SmallVectorImpl<unsigned> &Vals,
1179                      ValueEnumerator &VE) {
1180  unsigned ValID = VE.getValueID(V);
1181  Vals.push_back(InstID - ValID);
1182}
1183
1184static void pushValueSigned(const Value *V, unsigned InstID,
1185                            SmallVectorImpl<uint64_t> &Vals,
1186                            ValueEnumerator &VE) {
1187  unsigned ValID = VE.getValueID(V);
1188  int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1189  emitSignedInt64(Vals, diff);
1190}
1191
1192/// WriteInstruction - Emit an instruction to the specified stream.
1193static void WriteInstruction(const Instruction &I, unsigned InstID,
1194                             ValueEnumerator &VE, BitstreamWriter &Stream,
1195                             SmallVectorImpl<unsigned> &Vals) {
1196  unsigned Code = 0;
1197  unsigned AbbrevToUse = 0;
1198  VE.setInstructionID(&I);
1199  switch (I.getOpcode()) {
1200  default:
1201    if (Instruction::isCast(I.getOpcode())) {
1202      Code = bitc::FUNC_CODE_INST_CAST;
1203      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1204        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1205      Vals.push_back(VE.getTypeID(I.getType()));
1206      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1207    } else {
1208      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1209      Code = bitc::FUNC_CODE_INST_BINOP;
1210      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1211        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1212      pushValue(I.getOperand(1), InstID, Vals, VE);
1213      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1214      uint64_t Flags = GetOptimizationFlags(&I);
1215      if (Flags != 0) {
1216        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1217          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1218        Vals.push_back(Flags);
1219      }
1220    }
1221    break;
1222
1223  case Instruction::GetElementPtr:
1224    Code = bitc::FUNC_CODE_INST_GEP;
1225    if (cast<GEPOperator>(&I)->isInBounds())
1226      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1227    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1228      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1229    break;
1230  case Instruction::ExtractValue: {
1231    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1232    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1233    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1234    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1235      Vals.push_back(*i);
1236    break;
1237  }
1238  case Instruction::InsertValue: {
1239    Code = bitc::FUNC_CODE_INST_INSERTVAL;
1240    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1241    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1242    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1243    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1244      Vals.push_back(*i);
1245    break;
1246  }
1247  case Instruction::Select:
1248    Code = bitc::FUNC_CODE_INST_VSELECT;
1249    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1250    pushValue(I.getOperand(2), InstID, Vals, VE);
1251    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1252    break;
1253  case Instruction::ExtractElement:
1254    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1255    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1256    pushValue(I.getOperand(1), InstID, Vals, VE);
1257    break;
1258  case Instruction::InsertElement:
1259    Code = bitc::FUNC_CODE_INST_INSERTELT;
1260    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1261    pushValue(I.getOperand(1), InstID, Vals, VE);
1262    pushValue(I.getOperand(2), InstID, Vals, VE);
1263    break;
1264  case Instruction::ShuffleVector:
1265    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1266    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1267    pushValue(I.getOperand(1), InstID, Vals, VE);
1268    pushValue(I.getOperand(2), InstID, Vals, VE);
1269    break;
1270  case Instruction::ICmp:
1271  case Instruction::FCmp:
1272    // compare returning Int1Ty or vector of Int1Ty
1273    Code = bitc::FUNC_CODE_INST_CMP2;
1274    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1275    pushValue(I.getOperand(1), InstID, Vals, VE);
1276    Vals.push_back(cast<CmpInst>(I).getPredicate());
1277    break;
1278
1279  case Instruction::Ret:
1280    {
1281      Code = bitc::FUNC_CODE_INST_RET;
1282      unsigned NumOperands = I.getNumOperands();
1283      if (NumOperands == 0)
1284        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1285      else if (NumOperands == 1) {
1286        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1287          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1288      } else {
1289        for (unsigned i = 0, e = NumOperands; i != e; ++i)
1290          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1291      }
1292    }
1293    break;
1294  case Instruction::Br:
1295    {
1296      Code = bitc::FUNC_CODE_INST_BR;
1297      const BranchInst &II = cast<BranchInst>(I);
1298      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1299      if (II.isConditional()) {
1300        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1301        pushValue(II.getCondition(), InstID, Vals, VE);
1302      }
1303    }
1304    break;
1305  case Instruction::Switch:
1306    {
1307      Code = bitc::FUNC_CODE_INST_SWITCH;
1308      const SwitchInst &SI = cast<SwitchInst>(I);
1309      Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1310      pushValue(SI.getCondition(), InstID, Vals, VE);
1311      Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1312      for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1313           i != e; ++i) {
1314        Vals.push_back(VE.getValueID(i.getCaseValue()));
1315        Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1316      }
1317    }
1318    break;
1319  case Instruction::IndirectBr:
1320    Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1321    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1322    // Encode the address operand as relative, but not the basic blocks.
1323    pushValue(I.getOperand(0), InstID, Vals, VE);
1324    for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1325      Vals.push_back(VE.getValueID(I.getOperand(i)));
1326    break;
1327
1328  case Instruction::Invoke: {
1329    const InvokeInst *II = cast<InvokeInst>(&I);
1330    const Value *Callee(II->getCalledValue());
1331    PointerType *PTy = cast<PointerType>(Callee->getType());
1332    FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1333    Code = bitc::FUNC_CODE_INST_INVOKE;
1334
1335    Vals.push_back(VE.getAttributeID(II->getAttributes()));
1336    Vals.push_back(II->getCallingConv());
1337    Vals.push_back(VE.getValueID(II->getNormalDest()));
1338    Vals.push_back(VE.getValueID(II->getUnwindDest()));
1339    PushValueAndType(Callee, InstID, Vals, VE);
1340
1341    // Emit value #'s for the fixed parameters.
1342    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1343      pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1344
1345    // Emit type/value pairs for varargs params.
1346    if (FTy->isVarArg()) {
1347      for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1348           i != e; ++i)
1349        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1350    }
1351    break;
1352  }
1353  case Instruction::Resume:
1354    Code = bitc::FUNC_CODE_INST_RESUME;
1355    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1356    break;
1357  case Instruction::Unreachable:
1358    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1359    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1360    break;
1361
1362  case Instruction::PHI: {
1363    const PHINode &PN = cast<PHINode>(I);
1364    Code = bitc::FUNC_CODE_INST_PHI;
1365    // With the newer instruction encoding, forward references could give
1366    // negative valued IDs.  This is most common for PHIs, so we use
1367    // signed VBRs.
1368    SmallVector<uint64_t, 128> Vals64;
1369    Vals64.push_back(VE.getTypeID(PN.getType()));
1370    for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1371      pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1372      Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1373    }
1374    // Emit a Vals64 vector and exit.
1375    Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1376    Vals64.clear();
1377    return;
1378  }
1379
1380  case Instruction::LandingPad: {
1381    const LandingPadInst &LP = cast<LandingPadInst>(I);
1382    Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1383    Vals.push_back(VE.getTypeID(LP.getType()));
1384    PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1385    Vals.push_back(LP.isCleanup());
1386    Vals.push_back(LP.getNumClauses());
1387    for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1388      if (LP.isCatch(I))
1389        Vals.push_back(LandingPadInst::Catch);
1390      else
1391        Vals.push_back(LandingPadInst::Filter);
1392      PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1393    }
1394    break;
1395  }
1396
1397  case Instruction::Alloca:
1398    Code = bitc::FUNC_CODE_INST_ALLOCA;
1399    Vals.push_back(VE.getTypeID(I.getType()));
1400    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1401    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1402    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1403    break;
1404
1405  case Instruction::Load:
1406    if (cast<LoadInst>(I).isAtomic()) {
1407      Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1408      PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1409    } else {
1410      Code = bitc::FUNC_CODE_INST_LOAD;
1411      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1412        AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1413    }
1414    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1415    Vals.push_back(cast<LoadInst>(I).isVolatile());
1416    if (cast<LoadInst>(I).isAtomic()) {
1417      Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1418      Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1419    }
1420    break;
1421  case Instruction::Store:
1422    if (cast<StoreInst>(I).isAtomic())
1423      Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1424    else
1425      Code = bitc::FUNC_CODE_INST_STORE;
1426    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1427    pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1428    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1429    Vals.push_back(cast<StoreInst>(I).isVolatile());
1430    if (cast<StoreInst>(I).isAtomic()) {
1431      Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1432      Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1433    }
1434    break;
1435  case Instruction::AtomicCmpXchg:
1436    Code = bitc::FUNC_CODE_INST_CMPXCHG;
1437    PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1438    pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1439    pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1440    Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1441    Vals.push_back(GetEncodedOrdering(
1442                     cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1443    Vals.push_back(GetEncodedSynchScope(
1444                     cast<AtomicCmpXchgInst>(I).getSynchScope()));
1445    Vals.push_back(GetEncodedOrdering(
1446                     cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1447    break;
1448  case Instruction::AtomicRMW:
1449    Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1450    PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1451    pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1452    Vals.push_back(GetEncodedRMWOperation(
1453                     cast<AtomicRMWInst>(I).getOperation()));
1454    Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1455    Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1456    Vals.push_back(GetEncodedSynchScope(
1457                     cast<AtomicRMWInst>(I).getSynchScope()));
1458    break;
1459  case Instruction::Fence:
1460    Code = bitc::FUNC_CODE_INST_FENCE;
1461    Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1462    Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1463    break;
1464  case Instruction::Call: {
1465    const CallInst &CI = cast<CallInst>(I);
1466    PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1467    FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1468
1469    Code = bitc::FUNC_CODE_INST_CALL;
1470
1471    Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1472    Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1473    PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1474
1475    // Emit value #'s for the fixed parameters.
1476    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1477      // Check for labels (can happen with asm labels).
1478      if (FTy->getParamType(i)->isLabelTy())
1479        Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1480      else
1481        pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1482    }
1483
1484    // Emit type/value pairs for varargs params.
1485    if (FTy->isVarArg()) {
1486      for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1487           i != e; ++i)
1488        PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1489    }
1490    break;
1491  }
1492  case Instruction::VAArg:
1493    Code = bitc::FUNC_CODE_INST_VAARG;
1494    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1495    pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1496    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1497    break;
1498  }
1499
1500  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1501  Vals.clear();
1502}
1503
1504// Emit names for globals/functions etc.
1505static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1506                                  const ValueEnumerator &VE,
1507                                  BitstreamWriter &Stream) {
1508  if (VST.empty()) return;
1509  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1510
1511  // FIXME: Set up the abbrev, we know how many values there are!
1512  // FIXME: We know if the type names can use 7-bit ascii.
1513  SmallVector<unsigned, 64> NameVals;
1514
1515  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1516       SI != SE; ++SI) {
1517
1518    const ValueName &Name = *SI;
1519
1520    // Figure out the encoding to use for the name.
1521    bool is7Bit = true;
1522    bool isChar6 = true;
1523    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1524         C != E; ++C) {
1525      if (isChar6)
1526        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1527      if ((unsigned char)*C & 128) {
1528        is7Bit = false;
1529        break;  // don't bother scanning the rest.
1530      }
1531    }
1532
1533    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1534
1535    // VST_ENTRY:   [valueid, namechar x N]
1536    // VST_BBENTRY: [bbid, namechar x N]
1537    unsigned Code;
1538    if (isa<BasicBlock>(SI->getValue())) {
1539      Code = bitc::VST_CODE_BBENTRY;
1540      if (isChar6)
1541        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1542    } else {
1543      Code = bitc::VST_CODE_ENTRY;
1544      if (isChar6)
1545        AbbrevToUse = VST_ENTRY_6_ABBREV;
1546      else if (is7Bit)
1547        AbbrevToUse = VST_ENTRY_7_ABBREV;
1548    }
1549
1550    NameVals.push_back(VE.getValueID(SI->getValue()));
1551    for (const char *P = Name.getKeyData(),
1552         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1553      NameVals.push_back((unsigned char)*P);
1554
1555    // Emit the finished record.
1556    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1557    NameVals.clear();
1558  }
1559  Stream.ExitBlock();
1560}
1561
1562/// WriteFunction - Emit a function body to the module stream.
1563static void WriteFunction(const Function &F, ValueEnumerator &VE,
1564                          BitstreamWriter &Stream) {
1565  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1566  VE.incorporateFunction(F);
1567
1568  SmallVector<unsigned, 64> Vals;
1569
1570  // Emit the number of basic blocks, so the reader can create them ahead of
1571  // time.
1572  Vals.push_back(VE.getBasicBlocks().size());
1573  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1574  Vals.clear();
1575
1576  // If there are function-local constants, emit them now.
1577  unsigned CstStart, CstEnd;
1578  VE.getFunctionConstantRange(CstStart, CstEnd);
1579  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1580
1581  // If there is function-local metadata, emit it now.
1582  WriteFunctionLocalMetadata(F, VE, Stream);
1583
1584  // Keep a running idea of what the instruction ID is.
1585  unsigned InstID = CstEnd;
1586
1587  bool NeedsMetadataAttachment = false;
1588
1589  DebugLoc LastDL;
1590
1591  // Finally, emit all the instructions, in order.
1592  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1593    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1594         I != E; ++I) {
1595      WriteInstruction(*I, InstID, VE, Stream, Vals);
1596
1597      if (!I->getType()->isVoidTy())
1598        ++InstID;
1599
1600      // If the instruction has metadata, write a metadata attachment later.
1601      NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1602
1603      // If the instruction has a debug location, emit it.
1604      DebugLoc DL = I->getDebugLoc();
1605      if (DL.isUnknown()) {
1606        // nothing todo.
1607      } else if (DL == LastDL) {
1608        // Just repeat the same debug loc as last time.
1609        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1610      } else {
1611        MDNode *Scope, *IA;
1612        DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1613
1614        Vals.push_back(DL.getLine());
1615        Vals.push_back(DL.getCol());
1616        Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1617        Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1618        Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1619        Vals.clear();
1620
1621        LastDL = DL;
1622      }
1623    }
1624
1625  // Emit names for all the instructions etc.
1626  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1627
1628  if (NeedsMetadataAttachment)
1629    WriteMetadataAttachment(F, VE, Stream);
1630  VE.purgeFunction();
1631  Stream.ExitBlock();
1632}
1633
1634// Emit blockinfo, which defines the standard abbreviations etc.
1635static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1636  // We only want to emit block info records for blocks that have multiple
1637  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1638  // Other blocks can define their abbrevs inline.
1639  Stream.EnterBlockInfoBlock(2);
1640
1641  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1642    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1643    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1644    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1645    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1646    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1647    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1648                                   Abbv) != VST_ENTRY_8_ABBREV)
1649      llvm_unreachable("Unexpected abbrev ordering!");
1650  }
1651
1652  { // 7-bit fixed width VST_ENTRY strings.
1653    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1654    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1655    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1656    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1657    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1658    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1659                                   Abbv) != VST_ENTRY_7_ABBREV)
1660      llvm_unreachable("Unexpected abbrev ordering!");
1661  }
1662  { // 6-bit char6 VST_ENTRY strings.
1663    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1664    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1665    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1666    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1667    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1668    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1669                                   Abbv) != VST_ENTRY_6_ABBREV)
1670      llvm_unreachable("Unexpected abbrev ordering!");
1671  }
1672  { // 6-bit char6 VST_BBENTRY strings.
1673    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1674    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1675    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1676    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1677    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1678    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1679                                   Abbv) != VST_BBENTRY_6_ABBREV)
1680      llvm_unreachable("Unexpected abbrev ordering!");
1681  }
1682
1683
1684
1685  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1686    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1687    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1688    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1689                              Log2_32_Ceil(VE.getTypes().size()+1)));
1690    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1691                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1692      llvm_unreachable("Unexpected abbrev ordering!");
1693  }
1694
1695  { // INTEGER abbrev for CONSTANTS_BLOCK.
1696    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1697    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1698    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1699    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1700                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1701      llvm_unreachable("Unexpected abbrev ordering!");
1702  }
1703
1704  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1705    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1706    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1707    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1708    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1709                              Log2_32_Ceil(VE.getTypes().size()+1)));
1710    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1711
1712    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1713                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1714      llvm_unreachable("Unexpected abbrev ordering!");
1715  }
1716  { // NULL abbrev for CONSTANTS_BLOCK.
1717    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1718    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1719    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1720                                   Abbv) != CONSTANTS_NULL_Abbrev)
1721      llvm_unreachable("Unexpected abbrev ordering!");
1722  }
1723
1724  // FIXME: This should only use space for first class types!
1725
1726  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1727    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1728    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1729    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1730    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1731    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1732    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1733                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1734      llvm_unreachable("Unexpected abbrev ordering!");
1735  }
1736  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1737    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1738    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1739    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1740    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1741    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1742    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1743                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1744      llvm_unreachable("Unexpected abbrev ordering!");
1745  }
1746  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1747    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1748    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1749    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1750    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1751    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1752    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1753    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1754                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1755      llvm_unreachable("Unexpected abbrev ordering!");
1756  }
1757  { // INST_CAST abbrev for FUNCTION_BLOCK.
1758    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1759    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1760    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1761    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1762                              Log2_32_Ceil(VE.getTypes().size()+1)));
1763    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1764    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1765                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1766      llvm_unreachable("Unexpected abbrev ordering!");
1767  }
1768
1769  { // INST_RET abbrev for FUNCTION_BLOCK.
1770    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1771    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1772    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1773                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1774      llvm_unreachable("Unexpected abbrev ordering!");
1775  }
1776  { // INST_RET abbrev for FUNCTION_BLOCK.
1777    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1778    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1779    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1780    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1781                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1782      llvm_unreachable("Unexpected abbrev ordering!");
1783  }
1784  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1785    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1786    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1787    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1788                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1789      llvm_unreachable("Unexpected abbrev ordering!");
1790  }
1791
1792  Stream.ExitBlock();
1793}
1794
1795// Sort the Users based on the order in which the reader parses the bitcode
1796// file.
1797static bool bitcodereader_order(const User *lhs, const User *rhs) {
1798  // TODO: Implement.
1799  return true;
1800}
1801
1802static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1803                         BitstreamWriter &Stream) {
1804
1805  // One or zero uses can't get out of order.
1806  if (V->use_empty() || V->hasNUses(1))
1807    return;
1808
1809  // Make a copy of the in-memory use-list for sorting.
1810  SmallVector<const User*, 8> UserList(V->user_begin(), V->user_end());
1811
1812  // Sort the copy based on the order read by the BitcodeReader.
1813  std::sort(UserList.begin(), UserList.end(), bitcodereader_order);
1814
1815  // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1816  // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1817
1818  // TODO: Emit the USELIST_CODE_ENTRYs.
1819}
1820
1821static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1822                                 BitstreamWriter &Stream) {
1823  VE.incorporateFunction(*F);
1824
1825  for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1826       AI != AE; ++AI)
1827    WriteUseList(AI, VE, Stream);
1828  for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1829       ++BB) {
1830    WriteUseList(BB, VE, Stream);
1831    for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1832         ++II) {
1833      WriteUseList(II, VE, Stream);
1834      for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1835           OI != E; ++OI) {
1836        if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1837            isa<InlineAsm>(*OI))
1838          WriteUseList(*OI, VE, Stream);
1839      }
1840    }
1841  }
1842  VE.purgeFunction();
1843}
1844
1845// Emit use-lists.
1846static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1847                                BitstreamWriter &Stream) {
1848  Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1849
1850  // XXX: this modifies the module, but in a way that should never change the
1851  // behavior of any pass or codegen in LLVM. The problem is that GVs may
1852  // contain entries in the use_list that do not exist in the Module and are
1853  // not stored in the .bc file.
1854  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1855       I != E; ++I)
1856    I->removeDeadConstantUsers();
1857
1858  // Write the global variables.
1859  for (Module::const_global_iterator GI = M->global_begin(),
1860         GE = M->global_end(); GI != GE; ++GI) {
1861    WriteUseList(GI, VE, Stream);
1862
1863    // Write the global variable initializers.
1864    if (GI->hasInitializer())
1865      WriteUseList(GI->getInitializer(), VE, Stream);
1866  }
1867
1868  // Write the functions.
1869  for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1870    WriteUseList(FI, VE, Stream);
1871    if (!FI->isDeclaration())
1872      WriteFunctionUseList(FI, VE, Stream);
1873    if (FI->hasPrefixData())
1874      WriteUseList(FI->getPrefixData(), VE, Stream);
1875  }
1876
1877  // Write the aliases.
1878  for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1879       AI != AE; ++AI) {
1880    WriteUseList(AI, VE, Stream);
1881    WriteUseList(AI->getAliasee(), VE, Stream);
1882  }
1883
1884  Stream.ExitBlock();
1885}
1886
1887/// WriteModule - Emit the specified module to the bitstream.
1888static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1889  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1890
1891  SmallVector<unsigned, 1> Vals;
1892  unsigned CurVersion = 1;
1893  Vals.push_back(CurVersion);
1894  Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1895
1896  // Analyze the module, enumerating globals, functions, etc.
1897  ValueEnumerator VE(M);
1898
1899  // Emit blockinfo, which defines the standard abbreviations etc.
1900  WriteBlockInfo(VE, Stream);
1901
1902  // Emit information about attribute groups.
1903  WriteAttributeGroupTable(VE, Stream);
1904
1905  // Emit information about parameter attributes.
1906  WriteAttributeTable(VE, Stream);
1907
1908  // Emit information describing all of the types in the module.
1909  WriteTypeTable(VE, Stream);
1910
1911  // Emit top-level description of module, including target triple, inline asm,
1912  // descriptors for global variables, and function prototype info.
1913  WriteModuleInfo(M, VE, Stream);
1914
1915  // Emit constants.
1916  WriteModuleConstants(VE, Stream);
1917
1918  // Emit metadata.
1919  WriteModuleMetadata(M, VE, Stream);
1920
1921  // Emit metadata.
1922  WriteModuleMetadataStore(M, Stream);
1923
1924  // Emit names for globals/functions etc.
1925  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1926
1927  // Emit use-lists.
1928  if (EnablePreserveUseListOrdering)
1929    WriteModuleUseLists(M, VE, Stream);
1930
1931  // Emit function bodies.
1932  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1933    if (!F->isDeclaration())
1934      WriteFunction(*F, VE, Stream);
1935
1936  Stream.ExitBlock();
1937}
1938
1939/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1940/// header and trailer to make it compatible with the system archiver.  To do
1941/// this we emit the following header, and then emit a trailer that pads the
1942/// file out to be a multiple of 16 bytes.
1943///
1944/// struct bc_header {
1945///   uint32_t Magic;         // 0x0B17C0DE
1946///   uint32_t Version;       // Version, currently always 0.
1947///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1948///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1949///   uint32_t CPUType;       // CPU specifier.
1950///   ... potentially more later ...
1951/// };
1952enum {
1953  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1954  DarwinBCHeaderSize = 5*4
1955};
1956
1957static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1958                               uint32_t &Position) {
1959  Buffer[Position + 0] = (unsigned char) (Value >>  0);
1960  Buffer[Position + 1] = (unsigned char) (Value >>  8);
1961  Buffer[Position + 2] = (unsigned char) (Value >> 16);
1962  Buffer[Position + 3] = (unsigned char) (Value >> 24);
1963  Position += 4;
1964}
1965
1966static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1967                                         const Triple &TT) {
1968  unsigned CPUType = ~0U;
1969
1970  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1971  // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1972  // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1973  // specific constants here because they are implicitly part of the Darwin ABI.
1974  enum {
1975    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1976    DARWIN_CPU_TYPE_X86        = 7,
1977    DARWIN_CPU_TYPE_ARM        = 12,
1978    DARWIN_CPU_TYPE_POWERPC    = 18
1979  };
1980
1981  Triple::ArchType Arch = TT.getArch();
1982  if (Arch == Triple::x86_64)
1983    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1984  else if (Arch == Triple::x86)
1985    CPUType = DARWIN_CPU_TYPE_X86;
1986  else if (Arch == Triple::ppc)
1987    CPUType = DARWIN_CPU_TYPE_POWERPC;
1988  else if (Arch == Triple::ppc64)
1989    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1990  else if (Arch == Triple::arm || Arch == Triple::thumb)
1991    CPUType = DARWIN_CPU_TYPE_ARM;
1992
1993  // Traditional Bitcode starts after header.
1994  assert(Buffer.size() >= DarwinBCHeaderSize &&
1995         "Expected header size to be reserved");
1996  unsigned BCOffset = DarwinBCHeaderSize;
1997  unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
1998
1999  // Write the magic and version.
2000  unsigned Position = 0;
2001  WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2002  WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2003  WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2004  WriteInt32ToBuffer(BCSize     , Buffer, Position);
2005  WriteInt32ToBuffer(CPUType    , Buffer, Position);
2006
2007  // If the file is not a multiple of 16 bytes, insert dummy padding.
2008  while (Buffer.size() & 15)
2009    Buffer.push_back(0);
2010}
2011
2012/// WriteBitcodeToFile - Write the specified module to the specified output
2013/// stream.
2014void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2015  SmallVector<char, 0> Buffer;
2016  Buffer.reserve(256*1024);
2017
2018  // If this is darwin or another generic macho target, reserve space for the
2019  // header.
2020  Triple TT(M->getTargetTriple());
2021  if (TT.isOSDarwin())
2022    Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2023
2024  // Emit the module into the buffer.
2025  {
2026    BitstreamWriter Stream(Buffer);
2027
2028    // Emit the file header.
2029    Stream.Emit((unsigned)'B', 8);
2030    Stream.Emit((unsigned)'C', 8);
2031    Stream.Emit(0x0, 4);
2032    Stream.Emit(0xC, 4);
2033    Stream.Emit(0xE, 4);
2034    Stream.Emit(0xD, 4);
2035
2036    // Emit the module.
2037    WriteModule(M, Stream);
2038  }
2039
2040  if (TT.isOSDarwin())
2041    EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2042
2043  // Write the generated bitstream to "Out".
2044  Out.write((char*)&Buffer.front(), Buffer.size());
2045}
2046