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