BitcodeWriter.cpp revision 1224c386981f7948f298ed9ad444c40609570f2e 
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/MDNode.h"
23#include "llvm/Module.h"
24#include "llvm/Operator.h"
25#include "llvm/TypeSymbolTable.h"
26#include "llvm/ValueSymbolTable.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/MathExtras.h"
29#include "llvm/Support/Streams.h"
30#include "llvm/Support/raw_ostream.h"
31#include "llvm/System/Program.h"
32using namespace llvm;
33
34/// These are manifest constants used by the bitcode writer. They do not need to
35/// be kept in sync with the reader, but need to be consistent within this file.
36enum {
37  CurVersion = 0,
38
39  // VALUE_SYMTAB_BLOCK abbrev id's.
40  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
41  VST_ENTRY_7_ABBREV,
42  VST_ENTRY_6_ABBREV,
43  VST_BBENTRY_6_ABBREV,
44
45  // CONSTANTS_BLOCK abbrev id's.
46  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
47  CONSTANTS_INTEGER_ABBREV,
48  CONSTANTS_CE_CAST_Abbrev,
49  CONSTANTS_NULL_Abbrev,
50
51  // FUNCTION_BLOCK abbrev id's.
52  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
53  FUNCTION_INST_BINOP_ABBREV,
54  FUNCTION_INST_BINOP_FLAGS_ABBREV,
55  FUNCTION_INST_CAST_ABBREV,
56  FUNCTION_INST_RET_VOID_ABBREV,
57  FUNCTION_INST_RET_VAL_ABBREV,
58  FUNCTION_INST_UNREACHABLE_ABBREV
59};
60
61
62static unsigned GetEncodedCastOpcode(unsigned Opcode) {
63  switch (Opcode) {
64  default: llvm_unreachable("Unknown cast instruction!");
65  case Instruction::Trunc   : return bitc::CAST_TRUNC;
66  case Instruction::ZExt    : return bitc::CAST_ZEXT;
67  case Instruction::SExt    : return bitc::CAST_SEXT;
68  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
69  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
70  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
71  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
72  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
73  case Instruction::FPExt   : return bitc::CAST_FPEXT;
74  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
75  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
76  case Instruction::BitCast : return bitc::CAST_BITCAST;
77  }
78}
79
80static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
81  switch (Opcode) {
82  default: llvm_unreachable("Unknown binary instruction!");
83  case Instruction::Add:
84  case Instruction::FAdd: return bitc::BINOP_ADD;
85  case Instruction::Sub:
86  case Instruction::FSub: return bitc::BINOP_SUB;
87  case Instruction::Mul:
88  case Instruction::FMul: return bitc::BINOP_MUL;
89  case Instruction::UDiv: return bitc::BINOP_UDIV;
90  case Instruction::FDiv:
91  case Instruction::SDiv: return bitc::BINOP_SDIV;
92  case Instruction::URem: return bitc::BINOP_UREM;
93  case Instruction::FRem:
94  case Instruction::SRem: return bitc::BINOP_SREM;
95  case Instruction::Shl:  return bitc::BINOP_SHL;
96  case Instruction::LShr: return bitc::BINOP_LSHR;
97  case Instruction::AShr: return bitc::BINOP_ASHR;
98  case Instruction::And:  return bitc::BINOP_AND;
99  case Instruction::Or:   return bitc::BINOP_OR;
100  case Instruction::Xor:  return bitc::BINOP_XOR;
101  }
102}
103
104
105
106static void WriteStringRecord(unsigned Code, const std::string &Str,
107                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
108  SmallVector<unsigned, 64> Vals;
109
110  // Code: [strchar x N]
111  for (unsigned i = 0, e = Str.size(); i != e; ++i)
112    Vals.push_back(Str[i]);
113
114  // Emit the finished record.
115  Stream.EmitRecord(Code, Vals, AbbrevToUse);
116}
117
118// Emit information about parameter attributes.
119static void WriteAttributeTable(const ValueEnumerator &VE,
120                                BitstreamWriter &Stream) {
121  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
122  if (Attrs.empty()) return;
123
124  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
125
126  SmallVector<uint64_t, 64> Record;
127  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
128    const AttrListPtr &A = Attrs[i];
129    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
130      const AttributeWithIndex &PAWI = A.getSlot(i);
131      Record.push_back(PAWI.Index);
132
133      // FIXME: remove in LLVM 3.0
134      // Store the alignment in the bitcode as a 16-bit raw value instead of a
135      // 5-bit log2 encoded value. Shift the bits above the alignment up by
136      // 11 bits.
137      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
138      if (PAWI.Attrs & Attribute::Alignment)
139        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
140      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
141
142      Record.push_back(FauxAttr);
143    }
144
145    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
146    Record.clear();
147  }
148
149  Stream.ExitBlock();
150}
151
152/// WriteTypeTable - Write out the type table for a module.
153static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
154  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
155
156  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
157  SmallVector<uint64_t, 64> TypeVals;
158
159  // Abbrev for TYPE_CODE_POINTER.
160  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
161  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
162  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
163                            Log2_32_Ceil(VE.getTypes().size()+1)));
164  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
165  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
166
167  // Abbrev for TYPE_CODE_FUNCTION.
168  Abbv = new BitCodeAbbrev();
169  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
171  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
172  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
173  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
174                            Log2_32_Ceil(VE.getTypes().size()+1)));
175  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
176
177  // Abbrev for TYPE_CODE_STRUCT.
178  Abbv = new BitCodeAbbrev();
179  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
181  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
182  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
183                            Log2_32_Ceil(VE.getTypes().size()+1)));
184  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
185
186  // Abbrev for TYPE_CODE_ARRAY.
187  Abbv = new BitCodeAbbrev();
188  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
189  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
190  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
191                            Log2_32_Ceil(VE.getTypes().size()+1)));
192  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
193
194  // Emit an entry count so the reader can reserve space.
195  TypeVals.push_back(TypeList.size());
196  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
197  TypeVals.clear();
198
199  // Loop over all of the types, emitting each in turn.
200  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
201    const Type *T = TypeList[i].first;
202    int AbbrevToUse = 0;
203    unsigned Code = 0;
204
205    switch (T->getTypeID()) {
206    default: llvm_unreachable("Unknown type!");
207    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
208    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
209    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
210    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
211    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
212    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
213    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
214    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
215    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
216    case Type::IntegerTyID:
217      // INTEGER: [width]
218      Code = bitc::TYPE_CODE_INTEGER;
219      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
220      break;
221    case Type::PointerTyID: {
222      const PointerType *PTy = cast<PointerType>(T);
223      // POINTER: [pointee type, address space]
224      Code = bitc::TYPE_CODE_POINTER;
225      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
226      unsigned AddressSpace = PTy->getAddressSpace();
227      TypeVals.push_back(AddressSpace);
228      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
229      break;
230    }
231    case Type::FunctionTyID: {
232      const FunctionType *FT = cast<FunctionType>(T);
233      // FUNCTION: [isvararg, attrid, retty, paramty x N]
234      Code = bitc::TYPE_CODE_FUNCTION;
235      TypeVals.push_back(FT->isVarArg());
236      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
237      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
238      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
239        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
240      AbbrevToUse = FunctionAbbrev;
241      break;
242    }
243    case Type::StructTyID: {
244      const StructType *ST = cast<StructType>(T);
245      // STRUCT: [ispacked, eltty x N]
246      Code = bitc::TYPE_CODE_STRUCT;
247      TypeVals.push_back(ST->isPacked());
248      // Output all of the element types.
249      for (StructType::element_iterator I = ST->element_begin(),
250           E = ST->element_end(); I != E; ++I)
251        TypeVals.push_back(VE.getTypeID(*I));
252      AbbrevToUse = StructAbbrev;
253      break;
254    }
255    case Type::ArrayTyID: {
256      const ArrayType *AT = cast<ArrayType>(T);
257      // ARRAY: [numelts, eltty]
258      Code = bitc::TYPE_CODE_ARRAY;
259      TypeVals.push_back(AT->getNumElements());
260      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
261      AbbrevToUse = ArrayAbbrev;
262      break;
263    }
264    case Type::VectorTyID: {
265      const VectorType *VT = cast<VectorType>(T);
266      // VECTOR [numelts, eltty]
267      Code = bitc::TYPE_CODE_VECTOR;
268      TypeVals.push_back(VT->getNumElements());
269      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
270      break;
271    }
272    }
273
274    // Emit the finished record.
275    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
276    TypeVals.clear();
277  }
278
279  Stream.ExitBlock();
280}
281
282static unsigned getEncodedLinkage(const GlobalValue *GV) {
283  switch (GV->getLinkage()) {
284  default: llvm_unreachable("Invalid linkage!");
285  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
286  case GlobalValue::ExternalLinkage:            return 0;
287  case GlobalValue::WeakAnyLinkage:             return 1;
288  case GlobalValue::AppendingLinkage:           return 2;
289  case GlobalValue::InternalLinkage:            return 3;
290  case GlobalValue::LinkOnceAnyLinkage:         return 4;
291  case GlobalValue::DLLImportLinkage:           return 5;
292  case GlobalValue::DLLExportLinkage:           return 6;
293  case GlobalValue::ExternalWeakLinkage:        return 7;
294  case GlobalValue::CommonLinkage:              return 8;
295  case GlobalValue::PrivateLinkage:             return 9;
296  case GlobalValue::WeakODRLinkage:             return 10;
297  case GlobalValue::LinkOnceODRLinkage:         return 11;
298  case GlobalValue::AvailableExternallyLinkage: return 12;
299  case GlobalValue::LinkerPrivateLinkage:       return 13;
300  }
301}
302
303static unsigned getEncodedVisibility(const GlobalValue *GV) {
304  switch (GV->getVisibility()) {
305  default: llvm_unreachable("Invalid visibility!");
306  case GlobalValue::DefaultVisibility:   return 0;
307  case GlobalValue::HiddenVisibility:    return 1;
308  case GlobalValue::ProtectedVisibility: return 2;
309  }
310}
311
312// Emit top-level description of module, including target triple, inline asm,
313// descriptors for global variables, and function prototype info.
314static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
315                            BitstreamWriter &Stream) {
316  // Emit the list of dependent libraries for the Module.
317  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
318    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
319
320  // Emit various pieces of data attached to a module.
321  if (!M->getTargetTriple().empty())
322    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
323                      0/*TODO*/, Stream);
324  if (!M->getDataLayout().empty())
325    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
326                      0/*TODO*/, Stream);
327  if (!M->getModuleInlineAsm().empty())
328    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
329                      0/*TODO*/, Stream);
330
331  // Emit information about sections and GC, computing how many there are. Also
332  // compute the maximum alignment value.
333  std::map<std::string, unsigned> SectionMap;
334  std::map<std::string, unsigned> GCMap;
335  unsigned MaxAlignment = 0;
336  unsigned MaxGlobalType = 0;
337  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
338       GV != E; ++GV) {
339    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
340    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
341
342    if (!GV->hasSection()) continue;
343    // Give section names unique ID's.
344    unsigned &Entry = SectionMap[GV->getSection()];
345    if (Entry != 0) continue;
346    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
347                      0/*TODO*/, Stream);
348    Entry = SectionMap.size();
349  }
350  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
351    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
352    if (F->hasSection()) {
353      // Give section names unique ID's.
354      unsigned &Entry = SectionMap[F->getSection()];
355      if (!Entry) {
356        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
357                          0/*TODO*/, Stream);
358        Entry = SectionMap.size();
359      }
360    }
361    if (F->hasGC()) {
362      // Same for GC names.
363      unsigned &Entry = GCMap[F->getGC()];
364      if (!Entry) {
365        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
366                          0/*TODO*/, Stream);
367        Entry = GCMap.size();
368      }
369    }
370  }
371
372  // Emit abbrev for globals, now that we know # sections and max alignment.
373  unsigned SimpleGVarAbbrev = 0;
374  if (!M->global_empty()) {
375    // Add an abbrev for common globals with no visibility or thread localness.
376    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
377    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
379                              Log2_32_Ceil(MaxGlobalType+1)));
380    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
381    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
382    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
383    if (MaxAlignment == 0)                                      // Alignment.
384      Abbv->Add(BitCodeAbbrevOp(0));
385    else {
386      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
387      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
388                               Log2_32_Ceil(MaxEncAlignment+1)));
389    }
390    if (SectionMap.empty())                                    // Section.
391      Abbv->Add(BitCodeAbbrevOp(0));
392    else
393      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
394                               Log2_32_Ceil(SectionMap.size()+1)));
395    // Don't bother emitting vis + thread local.
396    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
397  }
398
399  // Emit the global variable information.
400  SmallVector<unsigned, 64> Vals;
401  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
402       GV != E; ++GV) {
403    unsigned AbbrevToUse = 0;
404
405    // GLOBALVAR: [type, isconst, initid,
406    //             linkage, alignment, section, visibility, threadlocal]
407    Vals.push_back(VE.getTypeID(GV->getType()));
408    Vals.push_back(GV->isConstant());
409    Vals.push_back(GV->isDeclaration() ? 0 :
410                   (VE.getValueID(GV->getInitializer()) + 1));
411    Vals.push_back(getEncodedLinkage(GV));
412    Vals.push_back(Log2_32(GV->getAlignment())+1);
413    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
414    if (GV->isThreadLocal() ||
415        GV->getVisibility() != GlobalValue::DefaultVisibility) {
416      Vals.push_back(getEncodedVisibility(GV));
417      Vals.push_back(GV->isThreadLocal());
418    } else {
419      AbbrevToUse = SimpleGVarAbbrev;
420    }
421
422    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
423    Vals.clear();
424  }
425
426  // Emit the function proto information.
427  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
428    // FUNCTION:  [type, callingconv, isproto, paramattr,
429    //             linkage, alignment, section, visibility, gc]
430    Vals.push_back(VE.getTypeID(F->getType()));
431    Vals.push_back(F->getCallingConv());
432    Vals.push_back(F->isDeclaration());
433    Vals.push_back(getEncodedLinkage(F));
434    Vals.push_back(VE.getAttributeID(F->getAttributes()));
435    Vals.push_back(Log2_32(F->getAlignment())+1);
436    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
437    Vals.push_back(getEncodedVisibility(F));
438    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
439
440    unsigned AbbrevToUse = 0;
441    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
442    Vals.clear();
443  }
444
445
446  // Emit the alias information.
447  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
448       AI != E; ++AI) {
449    Vals.push_back(VE.getTypeID(AI->getType()));
450    Vals.push_back(VE.getValueID(AI->getAliasee()));
451    Vals.push_back(getEncodedLinkage(AI));
452    Vals.push_back(getEncodedVisibility(AI));
453    unsigned AbbrevToUse = 0;
454    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
455    Vals.clear();
456  }
457}
458
459static uint64_t GetOptimizationFlags(const Value *V) {
460  uint64_t Flags = 0;
461
462  if (const OverflowingBinaryOperator *OBO =
463        dyn_cast<OverflowingBinaryOperator>(V)) {
464    if (OBO->hasNoSignedOverflow())
465      Flags |= 1 << bitc::OBO_NO_SIGNED_OVERFLOW;
466    if (OBO->hasNoUnsignedOverflow())
467      Flags |= 1 << bitc::OBO_NO_UNSIGNED_OVERFLOW;
468  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
469    if (Div->isExact())
470      Flags |= 1 << bitc::SDIV_EXACT;
471  }
472
473  return Flags;
474}
475
476static void WriteConstants(unsigned FirstVal, unsigned LastVal,
477                           const ValueEnumerator &VE,
478                           BitstreamWriter &Stream, bool isGlobal) {
479  if (FirstVal == LastVal) return;
480
481  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
482
483  unsigned AggregateAbbrev = 0;
484  unsigned String8Abbrev = 0;
485  unsigned CString7Abbrev = 0;
486  unsigned CString6Abbrev = 0;
487  unsigned MDString8Abbrev = 0;
488  unsigned MDString6Abbrev = 0;
489  // If this is a constant pool for the module, emit module-specific abbrevs.
490  if (isGlobal) {
491    // Abbrev for CST_CODE_AGGREGATE.
492    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
493    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
494    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
495    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
496    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
497
498    // Abbrev for CST_CODE_STRING.
499    Abbv = new BitCodeAbbrev();
500    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
501    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
502    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
503    String8Abbrev = Stream.EmitAbbrev(Abbv);
504    // Abbrev for CST_CODE_CSTRING.
505    Abbv = new BitCodeAbbrev();
506    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
507    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
508    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
509    CString7Abbrev = Stream.EmitAbbrev(Abbv);
510    // Abbrev for CST_CODE_CSTRING.
511    Abbv = new BitCodeAbbrev();
512    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
513    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
514    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
515    CString6Abbrev = Stream.EmitAbbrev(Abbv);
516
517    // Abbrev for CST_CODE_MDSTRING.
518    Abbv = new BitCodeAbbrev();
519    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
520    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
521    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
522    MDString8Abbrev = Stream.EmitAbbrev(Abbv);
523    // Abbrev for CST_CODE_MDSTRING.
524    Abbv = new BitCodeAbbrev();
525    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
526    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
527    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
528    MDString6Abbrev = Stream.EmitAbbrev(Abbv);
529  }
530
531  SmallVector<uint64_t, 64> Record;
532
533  const ValueEnumerator::ValueList &Vals = VE.getValues();
534  const Type *LastTy = 0;
535  for (unsigned i = FirstVal; i != LastVal; ++i) {
536    const Value *V = Vals[i].first;
537    // If we need to switch types, do so now.
538    if (V->getType() != LastTy) {
539      LastTy = V->getType();
540      Record.push_back(VE.getTypeID(LastTy));
541      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
542                        CONSTANTS_SETTYPE_ABBREV);
543      Record.clear();
544    }
545
546    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
547      Record.push_back(unsigned(IA->hasSideEffects()));
548
549      // Add the asm string.
550      const std::string &AsmStr = IA->getAsmString();
551      Record.push_back(AsmStr.size());
552      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
553        Record.push_back(AsmStr[i]);
554
555      // Add the constraint string.
556      const std::string &ConstraintStr = IA->getConstraintString();
557      Record.push_back(ConstraintStr.size());
558      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
559        Record.push_back(ConstraintStr[i]);
560      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
561      Record.clear();
562      continue;
563    }
564    const Constant *C = cast<Constant>(V);
565    unsigned Code = -1U;
566    unsigned AbbrevToUse = 0;
567    if (C->isNullValue()) {
568      Code = bitc::CST_CODE_NULL;
569    } else if (isa<UndefValue>(C)) {
570      Code = bitc::CST_CODE_UNDEF;
571    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
572      if (IV->getBitWidth() <= 64) {
573        int64_t V = IV->getSExtValue();
574        if (V >= 0)
575          Record.push_back(V << 1);
576        else
577          Record.push_back((-V << 1) | 1);
578        Code = bitc::CST_CODE_INTEGER;
579        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
580      } else {                             // Wide integers, > 64 bits in size.
581        // We have an arbitrary precision integer value to write whose
582        // bit width is > 64. However, in canonical unsigned integer
583        // format it is likely that the high bits are going to be zero.
584        // So, we only write the number of active words.
585        unsigned NWords = IV->getValue().getActiveWords();
586        const uint64_t *RawWords = IV->getValue().getRawData();
587        for (unsigned i = 0; i != NWords; ++i) {
588          int64_t V = RawWords[i];
589          if (V >= 0)
590            Record.push_back(V << 1);
591          else
592            Record.push_back((-V << 1) | 1);
593        }
594        Code = bitc::CST_CODE_WIDE_INTEGER;
595      }
596    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
597      Code = bitc::CST_CODE_FLOAT;
598      const Type *Ty = CFP->getType();
599      if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
600        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
601      } else if (Ty == Type::X86_FP80Ty) {
602        // api needed to prevent premature destruction
603        // bits are not in the same order as a normal i80 APInt, compensate.
604        APInt api = CFP->getValueAPF().bitcastToAPInt();
605        const uint64_t *p = api.getRawData();
606        Record.push_back((p[1] << 48) | (p[0] >> 16));
607        Record.push_back(p[0] & 0xffffLL);
608      } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
609        APInt api = CFP->getValueAPF().bitcastToAPInt();
610        const uint64_t *p = api.getRawData();
611        Record.push_back(p[0]);
612        Record.push_back(p[1]);
613      } else {
614        assert (0 && "Unknown FP type!");
615      }
616    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
617      // Emit constant strings specially.
618      unsigned NumOps = C->getNumOperands();
619      // If this is a null-terminated string, use the denser CSTRING encoding.
620      if (C->getOperand(NumOps-1)->isNullValue()) {
621        Code = bitc::CST_CODE_CSTRING;
622        --NumOps;  // Don't encode the null, which isn't allowed by char6.
623      } else {
624        Code = bitc::CST_CODE_STRING;
625        AbbrevToUse = String8Abbrev;
626      }
627      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
628      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
629      for (unsigned i = 0; i != NumOps; ++i) {
630        unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
631        Record.push_back(V);
632        isCStr7 &= (V & 128) == 0;
633        if (isCStrChar6)
634          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
635      }
636
637      if (isCStrChar6)
638        AbbrevToUse = CString6Abbrev;
639      else if (isCStr7)
640        AbbrevToUse = CString7Abbrev;
641    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
642               isa<ConstantVector>(V)) {
643      Code = bitc::CST_CODE_AGGREGATE;
644      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
645        Record.push_back(VE.getValueID(C->getOperand(i)));
646      AbbrevToUse = AggregateAbbrev;
647    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
648      switch (CE->getOpcode()) {
649      default:
650        if (Instruction::isCast(CE->getOpcode())) {
651          Code = bitc::CST_CODE_CE_CAST;
652          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
653          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
654          Record.push_back(VE.getValueID(C->getOperand(0)));
655          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
656        } else {
657          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
658          Code = bitc::CST_CODE_CE_BINOP;
659          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
660          Record.push_back(VE.getValueID(C->getOperand(0)));
661          Record.push_back(VE.getValueID(C->getOperand(1)));
662          uint64_t Flags = GetOptimizationFlags(CE);
663          if (Flags != 0)
664            Record.push_back(Flags);
665        }
666        break;
667      case Instruction::GetElementPtr:
668        Code = bitc::CST_CODE_CE_GEP;
669        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
670          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
671          Record.push_back(VE.getValueID(C->getOperand(i)));
672        }
673        break;
674      case Instruction::Select:
675        Code = bitc::CST_CODE_CE_SELECT;
676        Record.push_back(VE.getValueID(C->getOperand(0)));
677        Record.push_back(VE.getValueID(C->getOperand(1)));
678        Record.push_back(VE.getValueID(C->getOperand(2)));
679        break;
680      case Instruction::ExtractElement:
681        Code = bitc::CST_CODE_CE_EXTRACTELT;
682        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
683        Record.push_back(VE.getValueID(C->getOperand(0)));
684        Record.push_back(VE.getValueID(C->getOperand(1)));
685        break;
686      case Instruction::InsertElement:
687        Code = bitc::CST_CODE_CE_INSERTELT;
688        Record.push_back(VE.getValueID(C->getOperand(0)));
689        Record.push_back(VE.getValueID(C->getOperand(1)));
690        Record.push_back(VE.getValueID(C->getOperand(2)));
691        break;
692      case Instruction::ShuffleVector:
693        // If the return type and argument types are the same, this is a
694        // standard shufflevector instruction.  If the types are different,
695        // then the shuffle is widening or truncating the input vectors, and
696        // the argument type must also be encoded.
697        if (C->getType() == C->getOperand(0)->getType()) {
698          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
699        } else {
700          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
701          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
702        }
703        Record.push_back(VE.getValueID(C->getOperand(0)));
704        Record.push_back(VE.getValueID(C->getOperand(1)));
705        Record.push_back(VE.getValueID(C->getOperand(2)));
706        break;
707      case Instruction::ICmp:
708      case Instruction::FCmp:
709        Code = bitc::CST_CODE_CE_CMP;
710        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
711        Record.push_back(VE.getValueID(C->getOperand(0)));
712        Record.push_back(VE.getValueID(C->getOperand(1)));
713        Record.push_back(CE->getPredicate());
714        break;
715      }
716    } else if (const MDString *S = dyn_cast<MDString>(C)) {
717      Code = bitc::CST_CODE_MDSTRING;
718      AbbrevToUse = MDString6Abbrev;
719      for (unsigned i = 0, e = S->size(); i != e; ++i) {
720        char V = S->begin()[i];
721        Record.push_back(V);
722
723        if (!BitCodeAbbrevOp::isChar6(V))
724          AbbrevToUse = MDString8Abbrev;
725      }
726    } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
727      Code = bitc::CST_CODE_MDNODE;
728      for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
729        if (N->getElement(i)) {
730          Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
731          Record.push_back(VE.getValueID(N->getElement(i)));
732        } else {
733          Record.push_back(VE.getTypeID(Type::VoidTy));
734          Record.push_back(0);
735        }
736      }
737    } else {
738      llvm_unreachable("Unknown constant!");
739    }
740    Stream.EmitRecord(Code, Record, AbbrevToUse);
741    Record.clear();
742  }
743
744  Stream.ExitBlock();
745}
746
747static void WriteModuleConstants(const ValueEnumerator &VE,
748                                 BitstreamWriter &Stream) {
749  const ValueEnumerator::ValueList &Vals = VE.getValues();
750
751  // Find the first constant to emit, which is the first non-globalvalue value.
752  // We know globalvalues have been emitted by WriteModuleInfo.
753  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
754    if (!isa<GlobalValue>(Vals[i].first)) {
755      WriteConstants(i, Vals.size(), VE, Stream, true);
756      return;
757    }
758  }
759}
760
761/// PushValueAndType - The file has to encode both the value and type id for
762/// many values, because we need to know what type to create for forward
763/// references.  However, most operands are not forward references, so this type
764/// field is not needed.
765///
766/// This function adds V's value ID to Vals.  If the value ID is higher than the
767/// instruction ID, then it is a forward reference, and it also includes the
768/// type ID.
769static bool PushValueAndType(const Value *V, unsigned InstID,
770                             SmallVector<unsigned, 64> &Vals,
771                             ValueEnumerator &VE) {
772  unsigned ValID = VE.getValueID(V);
773  Vals.push_back(ValID);
774  if (ValID >= InstID) {
775    Vals.push_back(VE.getTypeID(V->getType()));
776    return true;
777  }
778  return false;
779}
780
781/// WriteInstruction - Emit an instruction to the specified stream.
782static void WriteInstruction(const Instruction &I, unsigned InstID,
783                             ValueEnumerator &VE, BitstreamWriter &Stream,
784                             SmallVector<unsigned, 64> &Vals) {
785  unsigned Code = 0;
786  unsigned AbbrevToUse = 0;
787  switch (I.getOpcode()) {
788  default:
789    if (Instruction::isCast(I.getOpcode())) {
790      Code = bitc::FUNC_CODE_INST_CAST;
791      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
792        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
793      Vals.push_back(VE.getTypeID(I.getType()));
794      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
795    } else {
796      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
797      Code = bitc::FUNC_CODE_INST_BINOP;
798      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
799        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
800      Vals.push_back(VE.getValueID(I.getOperand(1)));
801      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
802      uint64_t Flags = GetOptimizationFlags(&I);
803      if (Flags != 0) {
804        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
805          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
806        Vals.push_back(Flags);
807      }
808    }
809    break;
810
811  case Instruction::GetElementPtr:
812    Code = bitc::FUNC_CODE_INST_GEP;
813    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
814      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
815    break;
816  case Instruction::ExtractValue: {
817    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
818    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
819    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
820    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
821      Vals.push_back(*i);
822    break;
823  }
824  case Instruction::InsertValue: {
825    Code = bitc::FUNC_CODE_INST_INSERTVAL;
826    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
827    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
828    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
829    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
830      Vals.push_back(*i);
831    break;
832  }
833  case Instruction::Select:
834    Code = bitc::FUNC_CODE_INST_VSELECT;
835    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
836    Vals.push_back(VE.getValueID(I.getOperand(2)));
837    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
838    break;
839  case Instruction::ExtractElement:
840    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
841    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
842    Vals.push_back(VE.getValueID(I.getOperand(1)));
843    break;
844  case Instruction::InsertElement:
845    Code = bitc::FUNC_CODE_INST_INSERTELT;
846    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
847    Vals.push_back(VE.getValueID(I.getOperand(1)));
848    Vals.push_back(VE.getValueID(I.getOperand(2)));
849    break;
850  case Instruction::ShuffleVector:
851    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
852    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
853    Vals.push_back(VE.getValueID(I.getOperand(1)));
854    Vals.push_back(VE.getValueID(I.getOperand(2)));
855    break;
856  case Instruction::ICmp:
857  case Instruction::FCmp:
858    // compare returning Int1Ty or vector of Int1Ty
859    Code = bitc::FUNC_CODE_INST_CMP2;
860    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
861    Vals.push_back(VE.getValueID(I.getOperand(1)));
862    Vals.push_back(cast<CmpInst>(I).getPredicate());
863    break;
864
865  case Instruction::Ret:
866    {
867      Code = bitc::FUNC_CODE_INST_RET;
868      unsigned NumOperands = I.getNumOperands();
869      if (NumOperands == 0)
870        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
871      else if (NumOperands == 1) {
872        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
873          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
874      } else {
875        for (unsigned i = 0, e = NumOperands; i != e; ++i)
876          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
877      }
878    }
879    break;
880  case Instruction::Br:
881    {
882      Code = bitc::FUNC_CODE_INST_BR;
883      BranchInst &II(cast<BranchInst>(I));
884      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
885      if (II.isConditional()) {
886        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
887        Vals.push_back(VE.getValueID(II.getCondition()));
888      }
889    }
890    break;
891  case Instruction::Switch:
892    Code = bitc::FUNC_CODE_INST_SWITCH;
893    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
894    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
895      Vals.push_back(VE.getValueID(I.getOperand(i)));
896    break;
897  case Instruction::Invoke: {
898    const InvokeInst *II = cast<InvokeInst>(&I);
899    const Value *Callee(II->getCalledValue());
900    const PointerType *PTy = cast<PointerType>(Callee->getType());
901    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
902    Code = bitc::FUNC_CODE_INST_INVOKE;
903
904    Vals.push_back(VE.getAttributeID(II->getAttributes()));
905    Vals.push_back(II->getCallingConv());
906    Vals.push_back(VE.getValueID(II->getNormalDest()));
907    Vals.push_back(VE.getValueID(II->getUnwindDest()));
908    PushValueAndType(Callee, InstID, Vals, VE);
909
910    // Emit value #'s for the fixed parameters.
911    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
912      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
913
914    // Emit type/value pairs for varargs params.
915    if (FTy->isVarArg()) {
916      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
917           i != e; ++i)
918        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
919    }
920    break;
921  }
922  case Instruction::Unwind:
923    Code = bitc::FUNC_CODE_INST_UNWIND;
924    break;
925  case Instruction::Unreachable:
926    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
927    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
928    break;
929
930  case Instruction::PHI:
931    Code = bitc::FUNC_CODE_INST_PHI;
932    Vals.push_back(VE.getTypeID(I.getType()));
933    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
934      Vals.push_back(VE.getValueID(I.getOperand(i)));
935    break;
936
937  case Instruction::Malloc:
938    Code = bitc::FUNC_CODE_INST_MALLOC;
939    Vals.push_back(VE.getTypeID(I.getType()));
940    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
941    Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
942    break;
943
944  case Instruction::Free:
945    Code = bitc::FUNC_CODE_INST_FREE;
946    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
947    break;
948
949  case Instruction::Alloca:
950    Code = bitc::FUNC_CODE_INST_ALLOCA;
951    Vals.push_back(VE.getTypeID(I.getType()));
952    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
953    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
954    break;
955
956  case Instruction::Load:
957    Code = bitc::FUNC_CODE_INST_LOAD;
958    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
959      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
960
961    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
962    Vals.push_back(cast<LoadInst>(I).isVolatile());
963    break;
964  case Instruction::Store:
965    Code = bitc::FUNC_CODE_INST_STORE2;
966    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
967    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
968    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
969    Vals.push_back(cast<StoreInst>(I).isVolatile());
970    break;
971  case Instruction::Call: {
972    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
973    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
974
975    Code = bitc::FUNC_CODE_INST_CALL;
976
977    const CallInst *CI = cast<CallInst>(&I);
978    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
979    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
980    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
981
982    // Emit value #'s for the fixed parameters.
983    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
984      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
985
986    // Emit type/value pairs for varargs params.
987    if (FTy->isVarArg()) {
988      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
989      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
990           i != e; ++i)
991        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
992    }
993    break;
994  }
995  case Instruction::VAArg:
996    Code = bitc::FUNC_CODE_INST_VAARG;
997    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
998    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
999    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1000    break;
1001  }
1002
1003  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1004  Vals.clear();
1005}
1006
1007// Emit names for globals/functions etc.
1008static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1009                                  const ValueEnumerator &VE,
1010                                  BitstreamWriter &Stream) {
1011  if (VST.empty()) return;
1012  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1013
1014  // FIXME: Set up the abbrev, we know how many values there are!
1015  // FIXME: We know if the type names can use 7-bit ascii.
1016  SmallVector<unsigned, 64> NameVals;
1017
1018  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1019       SI != SE; ++SI) {
1020
1021    const ValueName &Name = *SI;
1022
1023    // Figure out the encoding to use for the name.
1024    bool is7Bit = true;
1025    bool isChar6 = true;
1026    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1027         C != E; ++C) {
1028      if (isChar6)
1029        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1030      if ((unsigned char)*C & 128) {
1031        is7Bit = false;
1032        break;  // don't bother scanning the rest.
1033      }
1034    }
1035
1036    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1037
1038    // VST_ENTRY:   [valueid, namechar x N]
1039    // VST_BBENTRY: [bbid, namechar x N]
1040    unsigned Code;
1041    if (isa<BasicBlock>(SI->getValue())) {
1042      Code = bitc::VST_CODE_BBENTRY;
1043      if (isChar6)
1044        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1045    } else {
1046      Code = bitc::VST_CODE_ENTRY;
1047      if (isChar6)
1048        AbbrevToUse = VST_ENTRY_6_ABBREV;
1049      else if (is7Bit)
1050        AbbrevToUse = VST_ENTRY_7_ABBREV;
1051    }
1052
1053    NameVals.push_back(VE.getValueID(SI->getValue()));
1054    for (const char *P = Name.getKeyData(),
1055         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1056      NameVals.push_back((unsigned char)*P);
1057
1058    // Emit the finished record.
1059    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1060    NameVals.clear();
1061  }
1062  Stream.ExitBlock();
1063}
1064
1065/// WriteFunction - Emit a function body to the module stream.
1066static void WriteFunction(const Function &F, ValueEnumerator &VE,
1067                          BitstreamWriter &Stream) {
1068  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1069  VE.incorporateFunction(F);
1070
1071  SmallVector<unsigned, 64> Vals;
1072
1073  // Emit the number of basic blocks, so the reader can create them ahead of
1074  // time.
1075  Vals.push_back(VE.getBasicBlocks().size());
1076  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1077  Vals.clear();
1078
1079  // If there are function-local constants, emit them now.
1080  unsigned CstStart, CstEnd;
1081  VE.getFunctionConstantRange(CstStart, CstEnd);
1082  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1083
1084  // Keep a running idea of what the instruction ID is.
1085  unsigned InstID = CstEnd;
1086
1087  // Finally, emit all the instructions, in order.
1088  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1089    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1090         I != E; ++I) {
1091      WriteInstruction(*I, InstID, VE, Stream, Vals);
1092      if (I->getType() != Type::VoidTy)
1093        ++InstID;
1094    }
1095
1096  // Emit names for all the instructions etc.
1097  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1098
1099  VE.purgeFunction();
1100  Stream.ExitBlock();
1101}
1102
1103/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1104static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1105                                 const ValueEnumerator &VE,
1106                                 BitstreamWriter &Stream) {
1107  if (TST.empty()) return;
1108
1109  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1110
1111  // 7-bit fixed width VST_CODE_ENTRY strings.
1112  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1113  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1114  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1115                            Log2_32_Ceil(VE.getTypes().size()+1)));
1116  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1117  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1118  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1119
1120  SmallVector<unsigned, 64> NameVals;
1121
1122  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1123       TI != TE; ++TI) {
1124    // TST_ENTRY: [typeid, namechar x N]
1125    NameVals.push_back(VE.getTypeID(TI->second));
1126
1127    const std::string &Str = TI->first;
1128    bool is7Bit = true;
1129    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1130      NameVals.push_back((unsigned char)Str[i]);
1131      if (Str[i] & 128)
1132        is7Bit = false;
1133    }
1134
1135    // Emit the finished record.
1136    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1137    NameVals.clear();
1138  }
1139
1140  Stream.ExitBlock();
1141}
1142
1143// Emit blockinfo, which defines the standard abbreviations etc.
1144static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1145  // We only want to emit block info records for blocks that have multiple
1146  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1147  // blocks can defined their abbrevs inline.
1148  Stream.EnterBlockInfoBlock(2);
1149
1150  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1151    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1152    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1153    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1154    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1155    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1156    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1157                                   Abbv) != VST_ENTRY_8_ABBREV)
1158      llvm_unreachable("Unexpected abbrev ordering!");
1159  }
1160
1161  { // 7-bit fixed width VST_ENTRY strings.
1162    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1163    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1164    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1165    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1166    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1167    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1168                                   Abbv) != VST_ENTRY_7_ABBREV)
1169      llvm_unreachable("Unexpected abbrev ordering!");
1170  }
1171  { // 6-bit char6 VST_ENTRY strings.
1172    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1173    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1174    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1175    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1176    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1177    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1178                                   Abbv) != VST_ENTRY_6_ABBREV)
1179      llvm_unreachable("Unexpected abbrev ordering!");
1180  }
1181  { // 6-bit char6 VST_BBENTRY strings.
1182    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1183    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1184    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1185    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1186    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1187    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1188                                   Abbv) != VST_BBENTRY_6_ABBREV)
1189      llvm_unreachable("Unexpected abbrev ordering!");
1190  }
1191
1192
1193
1194  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1195    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1196    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1197    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1198                              Log2_32_Ceil(VE.getTypes().size()+1)));
1199    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1200                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1201      llvm_unreachable("Unexpected abbrev ordering!");
1202  }
1203
1204  { // INTEGER abbrev for CONSTANTS_BLOCK.
1205    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1206    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1207    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1208    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1209                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1210      llvm_unreachable("Unexpected abbrev ordering!");
1211  }
1212
1213  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1214    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1215    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1216    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1217    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1218                              Log2_32_Ceil(VE.getTypes().size()+1)));
1219    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1220
1221    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1222                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1223      llvm_unreachable("Unexpected abbrev ordering!");
1224  }
1225  { // NULL abbrev for CONSTANTS_BLOCK.
1226    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1227    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1228    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1229                                   Abbv) != CONSTANTS_NULL_Abbrev)
1230      llvm_unreachable("Unexpected abbrev ordering!");
1231  }
1232
1233  // FIXME: This should only use space for first class types!
1234
1235  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1236    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1237    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1238    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1239    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1240    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1241    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1242                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1243      llvm_unreachable("Unexpected abbrev ordering!");
1244  }
1245  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1246    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1247    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1248    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1249    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1250    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1251    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1252                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1253      llvm_unreachable("Unexpected abbrev ordering!");
1254  }
1255  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1256    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1257    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1258    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1259    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1260    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1261    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1262    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1263                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1264      llvm_unreachable("Unexpected abbrev ordering!");
1265  }
1266  { // INST_CAST abbrev for FUNCTION_BLOCK.
1267    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1268    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1269    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1270    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1271                              Log2_32_Ceil(VE.getTypes().size()+1)));
1272    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1273    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1274                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1275      llvm_unreachable("Unexpected abbrev ordering!");
1276  }
1277
1278  { // INST_RET abbrev for FUNCTION_BLOCK.
1279    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1280    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1281    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1282                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1283      llvm_unreachable("Unexpected abbrev ordering!");
1284  }
1285  { // INST_RET abbrev for FUNCTION_BLOCK.
1286    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1287    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1288    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1289    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1290                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1291      llvm_unreachable("Unexpected abbrev ordering!");
1292  }
1293  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1294    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1295    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1296    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1297                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1298      llvm_unreachable("Unexpected abbrev ordering!");
1299  }
1300
1301  Stream.ExitBlock();
1302}
1303
1304
1305/// WriteModule - Emit the specified module to the bitstream.
1306static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1307  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1308
1309  // Emit the version number if it is non-zero.
1310  if (CurVersion) {
1311    SmallVector<unsigned, 1> Vals;
1312    Vals.push_back(CurVersion);
1313    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1314  }
1315
1316  // Analyze the module, enumerating globals, functions, etc.
1317  ValueEnumerator VE(M);
1318
1319  // Emit blockinfo, which defines the standard abbreviations etc.
1320  WriteBlockInfo(VE, Stream);
1321
1322  // Emit information about parameter attributes.
1323  WriteAttributeTable(VE, Stream);
1324
1325  // Emit information describing all of the types in the module.
1326  WriteTypeTable(VE, Stream);
1327
1328  // Emit top-level description of module, including target triple, inline asm,
1329  // descriptors for global variables, and function prototype info.
1330  WriteModuleInfo(M, VE, Stream);
1331
1332  // Emit constants.
1333  WriteModuleConstants(VE, Stream);
1334
1335  // Emit function bodies.
1336  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1337    if (!I->isDeclaration())
1338      WriteFunction(*I, VE, Stream);
1339
1340  // Emit the type symbol table information.
1341  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1342
1343  // Emit names for globals/functions etc.
1344  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1345
1346  Stream.ExitBlock();
1347}
1348
1349/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1350/// header and trailer to make it compatible with the system archiver.  To do
1351/// this we emit the following header, and then emit a trailer that pads the
1352/// file out to be a multiple of 16 bytes.
1353///
1354/// struct bc_header {
1355///   uint32_t Magic;         // 0x0B17C0DE
1356///   uint32_t Version;       // Version, currently always 0.
1357///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1358///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1359///   uint32_t CPUType;       // CPU specifier.
1360///   ... potentially more later ...
1361/// };
1362enum {
1363  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1364  DarwinBCHeaderSize = 5*4
1365};
1366
1367static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1368                               const std::string &TT) {
1369  unsigned CPUType = ~0U;
1370
1371  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1372  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1373  // specific constants here because they are implicitly part of the Darwin ABI.
1374  enum {
1375    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1376    DARWIN_CPU_TYPE_X86        = 7,
1377    DARWIN_CPU_TYPE_POWERPC    = 18
1378  };
1379
1380  if (TT.find("x86_64-") == 0)
1381    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1382  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1383           TT[4] == '-' && TT[1] - '3' < 6)
1384    CPUType = DARWIN_CPU_TYPE_X86;
1385  else if (TT.find("powerpc-") == 0)
1386    CPUType = DARWIN_CPU_TYPE_POWERPC;
1387  else if (TT.find("powerpc64-") == 0)
1388    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1389
1390  // Traditional Bitcode starts after header.
1391  unsigned BCOffset = DarwinBCHeaderSize;
1392
1393  Stream.Emit(0x0B17C0DE, 32);
1394  Stream.Emit(0         , 32);  // Version.
1395  Stream.Emit(BCOffset  , 32);
1396  Stream.Emit(0         , 32);  // Filled in later.
1397  Stream.Emit(CPUType   , 32);
1398}
1399
1400/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1401/// finalize the header.
1402static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1403  // Update the size field in the header.
1404  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1405
1406  // If the file is not a multiple of 16 bytes, insert dummy padding.
1407  while (BufferSize & 15) {
1408    Stream.Emit(0, 8);
1409    ++BufferSize;
1410  }
1411}
1412
1413
1414/// WriteBitcodeToFile - Write the specified module to the specified output
1415/// stream.
1416void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1417  raw_os_ostream RawOut(Out);
1418  // If writing to stdout, set binary mode.
1419  if (llvm::cout == Out)
1420    sys::Program::ChangeStdoutToBinary();
1421  WriteBitcodeToFile(M, RawOut);
1422}
1423
1424/// WriteBitcodeToFile - Write the specified module to the specified output
1425/// stream.
1426void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1427  std::vector<unsigned char> Buffer;
1428  BitstreamWriter Stream(Buffer);
1429
1430  Buffer.reserve(256*1024);
1431
1432  WriteBitcodeToStream( M, Stream );
1433
1434  // If writing to stdout, set binary mode.
1435  if (&llvm::outs() == &Out)
1436    sys::Program::ChangeStdoutToBinary();
1437
1438  // Write the generated bitstream to "Out".
1439  Out.write((char*)&Buffer.front(), Buffer.size());
1440
1441  // Make sure it hits disk now.
1442  Out.flush();
1443}
1444
1445/// WriteBitcodeToStream - Write the specified module to the specified output
1446/// stream.
1447void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1448  // If this is darwin, emit a file header and trailer if needed.
1449  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1450  if (isDarwin)
1451    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1452
1453  // Emit the file header.
1454  Stream.Emit((unsigned)'B', 8);
1455  Stream.Emit((unsigned)'C', 8);
1456  Stream.Emit(0x0, 4);
1457  Stream.Emit(0xC, 4);
1458  Stream.Emit(0xE, 4);
1459  Stream.Emit(0xD, 4);
1460
1461  // Emit the module.
1462  WriteModule(M, Stream);
1463
1464  if (isDarwin)
1465    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1466}
1467