BitcodeWriter.cpp revision 631a8ed3ff72a25c03c61319e85ff49aa601d464
1//===--- Bitcode/Writer/Writer.cpp - Bitcode Writer -----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by Chris Lattner and is distributed under 6// the University of Illinois Open Source 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/Module.h" 21#include "llvm/TypeSymbolTable.h" 22#include "llvm/ValueSymbolTable.h" 23#include "llvm/Support/MathExtras.h" 24using namespace llvm; 25 26static const unsigned CurVersion = 0; 27 28static void WriteStringRecord(unsigned Code, const std::string &Str, 29 unsigned AbbrevToUse, BitstreamWriter &Stream) { 30 SmallVector<unsigned, 64> Vals; 31 32 // Code: [strlen, strchar x N] 33 Vals.push_back(Str.size()); 34 for (unsigned i = 0, e = Str.size(); i != e; ++i) 35 Vals.push_back(Str[i]); 36 37 // Emit the finished record. 38 Stream.EmitRecord(Code, Vals, AbbrevToUse); 39} 40 41 42/// WriteTypeTable - Write out the type table for a module. 43static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) { 44 const ValueEnumerator::TypeList &TypeList = VE.getTypes(); 45 46 Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */); 47 SmallVector<uint64_t, 64> TypeVals; 48 49 // FIXME: Set up abbrevs now that we know the width of the type fields, etc. 50 51 // Emit an entry count so the reader can reserve space. 52 TypeVals.push_back(TypeList.size()); 53 Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals); 54 TypeVals.clear(); 55 56 // Loop over all of the types, emitting each in turn. 57 for (unsigned i = 0, e = TypeList.size(); i != e; ++i) { 58 const Type *T = TypeList[i].first; 59 int AbbrevToUse = 0; 60 unsigned Code = 0; 61 62 switch (T->getTypeID()) { 63 case Type::PackedStructTyID: // FIXME: Delete Type::PackedStructTyID. 64 default: assert(0 && "Unknown type!"); 65 case Type::VoidTyID: Code = bitc::TYPE_CODE_VOID; break; 66 case Type::FloatTyID: Code = bitc::TYPE_CODE_FLOAT; break; 67 case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break; 68 case Type::LabelTyID: Code = bitc::TYPE_CODE_LABEL; break; 69 case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break; 70 case Type::IntegerTyID: 71 // INTEGER: [width] 72 Code = bitc::TYPE_CODE_INTEGER; 73 TypeVals.push_back(cast<IntegerType>(T)->getBitWidth()); 74 break; 75 case Type::PointerTyID: 76 // POINTER: [pointee type] 77 Code = bitc::TYPE_CODE_POINTER; 78 TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType())); 79 break; 80 81 case Type::FunctionTyID: { 82 const FunctionType *FT = cast<FunctionType>(T); 83 // FUNCTION: [isvararg, #pararms, paramty x N] 84 Code = bitc::TYPE_CODE_FUNCTION; 85 TypeVals.push_back(FT->isVarArg()); 86 TypeVals.push_back(VE.getTypeID(FT->getReturnType())); 87 // FIXME: PARAM ATTR ID! 88 TypeVals.push_back(FT->getNumParams()); 89 for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) 90 TypeVals.push_back(VE.getTypeID(FT->getParamType(i))); 91 break; 92 } 93 case Type::StructTyID: { 94 const StructType *ST = cast<StructType>(T); 95 // STRUCT: [ispacked, #elts, eltty x N] 96 Code = bitc::TYPE_CODE_STRUCT; 97 TypeVals.push_back(ST->isPacked()); 98 TypeVals.push_back(ST->getNumElements()); 99 // Output all of the element types... 100 for (StructType::element_iterator I = ST->element_begin(), 101 E = ST->element_end(); I != E; ++I) 102 TypeVals.push_back(VE.getTypeID(*I)); 103 break; 104 } 105 case Type::ArrayTyID: { 106 const ArrayType *AT = cast<ArrayType>(T); 107 // ARRAY: [numelts, eltty] 108 Code = bitc::TYPE_CODE_ARRAY; 109 TypeVals.push_back(AT->getNumElements()); 110 TypeVals.push_back(VE.getTypeID(AT->getElementType())); 111 break; 112 } 113 case Type::VectorTyID: { 114 const VectorType *VT = cast<VectorType>(T); 115 // VECTOR [numelts, eltty] 116 Code = bitc::TYPE_CODE_VECTOR; 117 TypeVals.push_back(VT->getNumElements()); 118 TypeVals.push_back(VE.getTypeID(VT->getElementType())); 119 break; 120 } 121 } 122 123 // Emit the finished record. 124 Stream.EmitRecord(Code, TypeVals, AbbrevToUse); 125 TypeVals.clear(); 126 } 127 128 Stream.ExitBlock(); 129} 130 131static unsigned getEncodedLinkage(const GlobalValue *GV) { 132 switch (GV->getLinkage()) { 133 default: assert(0 && "Invalid linkage!"); 134 case GlobalValue::ExternalLinkage: return 0; 135 case GlobalValue::WeakLinkage: return 1; 136 case GlobalValue::AppendingLinkage: return 2; 137 case GlobalValue::InternalLinkage: return 3; 138 case GlobalValue::LinkOnceLinkage: return 4; 139 case GlobalValue::DLLImportLinkage: return 5; 140 case GlobalValue::DLLExportLinkage: return 6; 141 case GlobalValue::ExternalWeakLinkage: return 7; 142 } 143} 144 145static unsigned getEncodedVisibility(const GlobalValue *GV) { 146 switch (GV->getVisibility()) { 147 default: assert(0 && "Invalid visibility!"); 148 case GlobalValue::DefaultVisibility: return 0; 149 case GlobalValue::HiddenVisibility: return 1; 150 } 151} 152 153// Emit top-level description of module, including target triple, inline asm, 154// descriptors for global variables, and function prototype info. 155static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE, 156 BitstreamWriter &Stream) { 157 // Emit the list of dependent libraries for the Module. 158 for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I) 159 WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream); 160 161 // Emit various pieces of data attached to a module. 162 if (!M->getTargetTriple().empty()) 163 WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(), 164 0/*TODO*/, Stream); 165 if (!M->getDataLayout().empty()) 166 WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(), 167 0/*TODO*/, Stream); 168 if (!M->getModuleInlineAsm().empty()) 169 WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(), 170 0/*TODO*/, Stream); 171 172 // Emit information about sections, computing how many there are. Also 173 // compute the maximum alignment value. 174 std::map<std::string, unsigned> SectionMap; 175 unsigned MaxAlignment = 0; 176 unsigned MaxGlobalType = 0; 177 for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end(); 178 GV != E; ++GV) { 179 MaxAlignment = std::max(MaxAlignment, GV->getAlignment()); 180 MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType())); 181 182 if (!GV->hasSection()) continue; 183 // Give section names unique ID's. 184 unsigned &Entry = SectionMap[GV->getSection()]; 185 if (Entry != 0) continue; 186 WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(), 187 0/*TODO*/, Stream); 188 Entry = SectionMap.size(); 189 } 190 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) { 191 MaxAlignment = std::max(MaxAlignment, F->getAlignment()); 192 if (!F->hasSection()) continue; 193 // Give section names unique ID's. 194 unsigned &Entry = SectionMap[F->getSection()]; 195 if (Entry != 0) continue; 196 WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(), 197 0/*TODO*/, Stream); 198 Entry = SectionMap.size(); 199 } 200 201 // Emit abbrev for globals, now that we know # sections and max alignment. 202 unsigned SimpleGVarAbbrev = 0; 203 if (!M->global_empty()) { 204 // Add an abbrev for common globals with no visibility or thread localness. 205 BitCodeAbbrev *Abbv = new BitCodeAbbrev(); 206 Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR)); 207 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 208 Log2_32_Ceil(MaxGlobalType+1))); 209 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 1)); // Constant. 210 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Initializer. 211 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 3)); // Linkage. 212 if (MaxAlignment == 0) // Alignment. 213 Abbv->Add(BitCodeAbbrevOp(0)); 214 else { 215 unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1; 216 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 217 Log2_32_Ceil(MaxEncAlignment+1))); 218 } 219 if (SectionMap.empty()) // Section. 220 Abbv->Add(BitCodeAbbrevOp(0)); 221 else 222 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 223 Log2_32_Ceil(SectionMap.size()+1))); 224 // Don't bother emitting vis + thread local. 225 SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv); 226 } 227 228 // Emit the global variable information. 229 SmallVector<unsigned, 64> Vals; 230 for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end(); 231 GV != E; ++GV) { 232 unsigned AbbrevToUse = 0; 233 234 // GLOBALVAR: [type, isconst, initid, 235 // linkage, alignment, section, visibility, threadlocal] 236 Vals.push_back(VE.getTypeID(GV->getType())); 237 Vals.push_back(GV->isConstant()); 238 Vals.push_back(GV->isDeclaration() ? 0 : 239 (VE.getValueID(GV->getInitializer()) + 1)); 240 Vals.push_back(getEncodedLinkage(GV)); 241 Vals.push_back(Log2_32(GV->getAlignment())+1); 242 Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0); 243 if (GV->isThreadLocal() || 244 GV->getVisibility() != GlobalValue::DefaultVisibility) { 245 Vals.push_back(getEncodedVisibility(GV)); 246 Vals.push_back(GV->isThreadLocal()); 247 } else { 248 AbbrevToUse = SimpleGVarAbbrev; 249 } 250 251 Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse); 252 Vals.clear(); 253 } 254 255 // Emit the function proto information. 256 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) { 257 // FUNCTION: [type, callingconv, isproto, linkage, alignment, section, 258 // visibility] 259 Vals.push_back(VE.getTypeID(F->getType())); 260 Vals.push_back(F->getCallingConv()); 261 Vals.push_back(F->isDeclaration()); 262 Vals.push_back(getEncodedLinkage(F)); 263 Vals.push_back(Log2_32(F->getAlignment())+1); 264 Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0); 265 Vals.push_back(getEncodedVisibility(F)); 266 267 unsigned AbbrevToUse = 0; 268 Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse); 269 Vals.clear(); 270 } 271} 272 273 274/// WriteTypeSymbolTable - Emit a block for the specified type symtab. 275static void WriteTypeSymbolTable(const TypeSymbolTable &TST, 276 const ValueEnumerator &VE, 277 BitstreamWriter &Stream) { 278 if (TST.empty()) return; 279 280 Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3); 281 282 // FIXME: Set up the abbrev, we know how many types there are! 283 // FIXME: We know if the type names can use 7-bit ascii. 284 285 SmallVector<unsigned, 64> NameVals; 286 287 for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end(); 288 TI != TE; ++TI) { 289 unsigned AbbrevToUse = 0; 290 291 // TST_ENTRY: [typeid, namelen, namechar x N] 292 NameVals.push_back(VE.getTypeID(TI->second)); 293 294 const std::string &Str = TI->first; 295 NameVals.push_back(Str.size()); 296 for (unsigned i = 0, e = Str.size(); i != e; ++i) 297 NameVals.push_back(Str[i]); 298 299 // Emit the finished record. 300 Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, AbbrevToUse); 301 NameVals.clear(); 302 } 303 304 Stream.ExitBlock(); 305} 306 307// Emit names for globals/functions etc. 308static void WriteValueSymbolTable(const ValueSymbolTable &VST, 309 const ValueEnumerator &VE, 310 BitstreamWriter &Stream) { 311 if (VST.empty()) return; 312 Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 3); 313 314 // FIXME: Set up the abbrev, we know how many values there are! 315 // FIXME: We know if the type names can use 7-bit ascii. 316 SmallVector<unsigned, 64> NameVals; 317 318 for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end(); 319 SI != SE; ++SI) { 320 unsigned AbbrevToUse = 0; 321 322 // VST_ENTRY: [valueid, namelen, namechar x N] 323 NameVals.push_back(VE.getValueID(SI->getValue())); 324 325 NameVals.push_back(SI->getKeyLength()); 326 for (const char *P = SI->getKeyData(), 327 *E = SI->getKeyData()+SI->getKeyLength(); P != E; ++P) 328 NameVals.push_back((unsigned char)*P); 329 330 // Emit the finished record. 331 Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, AbbrevToUse); 332 NameVals.clear(); 333 } 334 Stream.ExitBlock(); 335} 336 337static void WriteConstants(unsigned FirstVal, unsigned LastVal, 338 const ValueEnumerator &VE, 339 BitstreamWriter &Stream) { 340 if (FirstVal == LastVal) return; 341 342 Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 2); 343 344 // FIXME: Install and use abbrevs to reduce size. 345 346 SmallVector<uint64_t, 64> Record; 347 348 const ValueEnumerator::ValueList &Vals = VE.getValues(); 349 const Type *LastTy = 0; 350 for (unsigned i = FirstVal; i != LastVal; ++i) { 351 const Value *V = Vals[i].first; 352 // If we need to switch types, do so now. 353 if (V->getType() != LastTy) { 354 LastTy = V->getType(); 355 Record.push_back(VE.getTypeID(LastTy)); 356 Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record); 357 Record.clear(); 358 } 359 360 if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) { 361 assert(0 && IA && "FIXME: Inline asm writing unimp!"); 362 continue; 363 } 364 const Constant *C = cast<Constant>(V); 365 unsigned Code = -1U; 366 unsigned AbbrevToUse = 0; 367 if (C->isNullValue()) { 368 Code = bitc::CST_CODE_NULL; 369 } else if (isa<UndefValue>(C)) { 370 Code = bitc::CST_CODE_UNDEF; 371 } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) { 372 if (IV->getBitWidth() <= 64) { 373 int64_t V = IV->getSExtValue(); 374 if (V >= 0) 375 Record.push_back(V << 1); 376 else 377 Record.push_back((-V << 1) | 1); 378 Code = bitc::CST_CODE_INTEGER; 379 } else { // Wide integers, > 64 bits in size. 380 // We have an arbitrary precision integer value to write whose 381 // bit width is > 64. However, in canonical unsigned integer 382 // format it is likely that the high bits are going to be zero. 383 // So, we only write the number of active words. 384 unsigned NWords = IV->getValue().getActiveWords(); 385 const uint64_t *RawWords = IV->getValue().getRawData(); 386 Record.push_back(NWords); 387 for (unsigned i = 0; i != NWords; ++i) { 388 int64_t V = RawWords[i]; 389 if (V >= 0) 390 Record.push_back(V << 1); 391 else 392 Record.push_back((-V << 1) | 1); 393 } 394 Code = bitc::CST_CODE_WIDE_INTEGER; 395 } 396 } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) { 397 Code = bitc::CST_CODE_FLOAT; 398 if (CFP->getType() == Type::FloatTy) { 399 Record.push_back(FloatToBits((float)CFP->getValue())); 400 } else { 401 assert (CFP->getType() == Type::DoubleTy && "Unknown FP type!"); 402 Record.push_back(DoubleToBits((double)CFP->getValue())); 403 } 404 } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) || 405 isa<ConstantVector>(V)) { 406 Code = bitc::CST_CODE_AGGREGATE; 407 Record.push_back(C->getNumOperands()); 408 for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) 409 Record.push_back(VE.getValueID(C->getOperand(i))); 410 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) { 411 Code = bitc::CST_CODE_CONSTEXPR; 412 // FIXME: optimize for binops, compares, etc. 413 Record.push_back(CE->getOpcode()); 414 Record.push_back(CE->getNumOperands()); 415 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 416 Record.push_back(VE.getValueID(C->getOperand(i))); 417 // Compares also pass their predicate. 418 if (CE->isCompare()) 419 Record.push_back((unsigned)CE->getPredicate()); 420 } else { 421 assert(0 && "Unknown constant!"); 422 } 423 Stream.EmitRecord(Code, Record, AbbrevToUse); 424 Record.clear(); 425 } 426 427 Stream.ExitBlock(); 428} 429 430static void WriteModuleConstants(const ValueEnumerator &VE, 431 BitstreamWriter &Stream) { 432 const ValueEnumerator::ValueList &Vals = VE.getValues(); 433 434 // Find the first constant to emit, which is the first non-globalvalue value. 435 // We know globalvalues have been emitted by WriteModuleInfo. 436 for (unsigned i = 0, e = Vals.size(); i != e; ++i) { 437 if (!isa<GlobalValue>(Vals[i].first)) { 438 WriteConstants(i, Vals.size(), VE, Stream); 439 return; 440 } 441 } 442} 443 444/// WriteModule - Emit the specified module to the bitstream. 445static void WriteModule(const Module *M, BitstreamWriter &Stream) { 446 Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3); 447 448 // Emit the version number if it is non-zero. 449 if (CurVersion) { 450 SmallVector<unsigned, 1> VersionVals; 451 VersionVals.push_back(CurVersion); 452 Stream.EmitRecord(bitc::MODULE_CODE_VERSION, VersionVals); 453 } 454 455 // Analyze the module, enumerating globals, functions, etc. 456 ValueEnumerator VE(M); 457 458 // Emit information describing all of the types in the module. 459 WriteTypeTable(VE, Stream); 460 461 // Emit top-level description of module, including target triple, inline asm, 462 // descriptors for global variables, and function prototype info. 463 WriteModuleInfo(M, VE, Stream); 464 465 // Emit constants. 466 WriteModuleConstants(VE, Stream); 467 468 // Emit the type symbol table information. 469 WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream); 470 471 // Emit names for globals/functions etc. 472 WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream); 473 474 Stream.ExitBlock(); 475} 476 477/// WriteBitcodeToFile - Write the specified module to the specified output 478/// stream. 479void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) { 480 std::vector<unsigned char> Buffer; 481 BitstreamWriter Stream(Buffer); 482 483 Buffer.reserve(256*1024); 484 485 // Emit the file header. 486 Stream.Emit((unsigned)'B', 8); 487 Stream.Emit((unsigned)'C', 8); 488 Stream.Emit(0x0, 4); 489 Stream.Emit(0xC, 4); 490 Stream.Emit(0xE, 4); 491 Stream.Emit(0xD, 4); 492 493 // Emit the module. 494 WriteModule(M, Stream); 495 496 // Write the generated bitstream to "Out". 497 Out.write((char*)&Buffer.front(), Buffer.size()); 498} 499