BitcodeWriter.cpp revision d127c1b5f3785a4a957ccf70b79a96adfc223259
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/DerivedTypes.h" 19#include "llvm/Module.h" 20#include "llvm/TypeSymbolTable.h" 21#include "llvm/Support/MathExtras.h" 22using namespace llvm; 23 24static const unsigned CurVersion = 0; 25 26static void WriteStringRecord(unsigned Code, const std::string &Str, 27 unsigned AbbrevToUse, BitstreamWriter &Stream) { 28 SmallVector<unsigned, 64> Vals; 29 30 // Code: [strlen, strchar x N] 31 Vals.push_back(Str.size()); 32 for (unsigned i = 0, e = Str.size(); i != e; ++i) 33 Vals.push_back(Str[i]); 34 35 // Emit the finished record. 36 Stream.EmitRecord(Code, Vals, AbbrevToUse); 37} 38 39 40/// WriteTypeTable - Write out the type table for a module. 41static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) { 42 const ValueEnumerator::TypeList &TypeList = VE.getTypes(); 43 44 Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */); 45 SmallVector<uint64_t, 64> TypeVals; 46 47 // FIXME: Set up abbrevs now that we know the width of the type fields, etc. 48 49 // Emit an entry count so the reader can reserve space. 50 TypeVals.push_back(TypeList.size()); 51 Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals); 52 TypeVals.clear(); 53 54 // Loop over all of the types, emitting each in turn. 55 for (unsigned i = 0, e = TypeList.size(); i != e; ++i) { 56 const Type *T = TypeList[i].first; 57 int AbbrevToUse = 0; 58 unsigned Code = 0; 59 60 switch (T->getTypeID()) { 61 case Type::PackedStructTyID: // FIXME: Delete Type::PackedStructTyID. 62 default: assert(0 && "Unknown type!"); 63 case Type::VoidTyID: Code = bitc::TYPE_CODE_VOID; break; 64 case Type::FloatTyID: Code = bitc::TYPE_CODE_FLOAT; break; 65 case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break; 66 case Type::LabelTyID: Code = bitc::TYPE_CODE_LABEL; break; 67 case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break; 68 case Type::IntegerTyID: 69 // INTEGER: [width] 70 Code = bitc::TYPE_CODE_INTEGER; 71 TypeVals.push_back(cast<IntegerType>(T)->getBitWidth()); 72 break; 73 case Type::PointerTyID: 74 // POINTER: [pointee type] 75 Code = bitc::TYPE_CODE_POINTER; 76 TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType())); 77 break; 78 79 case Type::FunctionTyID: { 80 const FunctionType *FT = cast<FunctionType>(T); 81 // FUNCTION: [isvararg, #pararms, paramty x N] 82 Code = bitc::TYPE_CODE_FUNCTION; 83 TypeVals.push_back(FT->isVarArg()); 84 TypeVals.push_back(VE.getTypeID(FT->getReturnType())); 85 // FIXME: PARAM ATTR ID! 86 TypeVals.push_back(FT->getNumParams()); 87 for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) 88 TypeVals.push_back(VE.getTypeID(FT->getParamType(i))); 89 break; 90 } 91 case Type::StructTyID: { 92 const StructType *ST = cast<StructType>(T); 93 // STRUCT: [ispacked, #elts, eltty x N] 94 Code = bitc::TYPE_CODE_STRUCT; 95 TypeVals.push_back(ST->isPacked()); 96 TypeVals.push_back(ST->getNumElements()); 97 // Output all of the element types... 98 for (StructType::element_iterator I = ST->element_begin(), 99 E = ST->element_end(); I != E; ++I) 100 TypeVals.push_back(VE.getTypeID(*I)); 101 break; 102 } 103 case Type::ArrayTyID: { 104 const ArrayType *AT = cast<ArrayType>(T); 105 // ARRAY: [numelts, eltty] 106 Code = bitc::TYPE_CODE_ARRAY; 107 TypeVals.push_back(AT->getNumElements()); 108 TypeVals.push_back(VE.getTypeID(AT->getElementType())); 109 break; 110 } 111 case Type::VectorTyID: { 112 const VectorType *VT = cast<VectorType>(T); 113 // VECTOR [numelts, eltty] 114 Code = bitc::TYPE_CODE_VECTOR; 115 TypeVals.push_back(VT->getNumElements()); 116 TypeVals.push_back(VE.getTypeID(VT->getElementType())); 117 break; 118 } 119 } 120 121 // Emit the finished record. 122 Stream.EmitRecord(Code, TypeVals, AbbrevToUse); 123 TypeVals.clear(); 124 } 125 126 Stream.ExitBlock(); 127} 128 129/// WriteTypeSymbolTable - Emit a block for the specified type symtab. 130static void WriteTypeSymbolTable(const TypeSymbolTable &TST, 131 const ValueEnumerator &VE, 132 BitstreamWriter &Stream) { 133 if (TST.empty()) return; 134 135 Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3); 136 137 // FIXME: Set up the abbrev, we know how many types there are! 138 // FIXME: We know if the type names can use 7-bit ascii. 139 140 SmallVector<unsigned, 64> NameVals; 141 142 for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end(); 143 TI != TE; ++TI) { 144 unsigned AbbrevToUse = 0; 145 146 // TST_ENTRY: [typeid, namelen, namechar x N] 147 NameVals.push_back(VE.getTypeID(TI->second)); 148 149 const std::string &Str = TI->first; 150 NameVals.push_back(Str.size()); 151 for (unsigned i = 0, e = Str.size(); i != e; ++i) 152 NameVals.push_back(Str[i]); 153 154 // Emit the finished record. 155 Stream.EmitRecord(bitc::TST_ENTRY_CODE, NameVals, AbbrevToUse); 156 NameVals.clear(); 157 } 158 159 Stream.ExitBlock(); 160} 161 162static unsigned getEncodedLinkage(const GlobalValue *GV) { 163 switch (GV->getLinkage()) { 164 default: assert(0 && "Invalid linkage!"); 165 case GlobalValue::ExternalLinkage: return 0; 166 case GlobalValue::WeakLinkage: return 1; 167 case GlobalValue::AppendingLinkage: return 2; 168 case GlobalValue::InternalLinkage: return 3; 169 case GlobalValue::LinkOnceLinkage: return 4; 170 case GlobalValue::DLLImportLinkage: return 5; 171 case GlobalValue::DLLExportLinkage: return 6; 172 case GlobalValue::ExternalWeakLinkage: return 7; 173 } 174} 175 176static unsigned getEncodedVisibility(const GlobalValue *GV) { 177 switch (GV->getVisibility()) { 178 default: assert(0 && "Invalid visibility!"); 179 case GlobalValue::DefaultVisibility: return 0; 180 case GlobalValue::HiddenVisibility: return 1; 181 } 182} 183 184// Emit top-level description of module, including target triple, inline asm, 185// descriptors for global variables, and function prototype info. 186static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE, 187 BitstreamWriter &Stream) { 188 // Emit the list of dependent libraries for the Module. 189 for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I) 190 WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream); 191 192 // Emit various pieces of data attached to a module. 193 if (!M->getTargetTriple().empty()) 194 WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(), 195 0/*TODO*/, Stream); 196 if (!M->getDataLayout().empty()) 197 WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(), 198 0/*TODO*/, Stream); 199 if (!M->getModuleInlineAsm().empty()) 200 WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(), 201 0/*TODO*/, Stream); 202 203 // Emit information about sections, computing how many there are. Also 204 // compute the maximum alignment value. 205 std::map<std::string, unsigned> SectionMap; 206 unsigned MaxAlignment = 0; 207 unsigned MaxGlobalType = 0; 208 for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end(); 209 GV != E; ++GV) { 210 MaxAlignment = std::max(MaxAlignment, GV->getAlignment()); 211 MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType())); 212 213 if (!GV->hasSection()) continue; 214 // Give section names unique ID's. 215 unsigned &Entry = SectionMap[GV->getSection()]; 216 if (Entry != 0) continue; 217 WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(), 218 0/*TODO*/, Stream); 219 Entry = SectionMap.size(); 220 } 221 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) { 222 MaxAlignment = std::max(MaxAlignment, F->getAlignment()); 223 if (!F->hasSection()) continue; 224 // Give section names unique ID's. 225 unsigned &Entry = SectionMap[F->getSection()]; 226 if (Entry != 0) continue; 227 WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(), 228 0/*TODO*/, Stream); 229 Entry = SectionMap.size(); 230 } 231 232 // Emit abbrev for globals, now that we know # sections and max alignment. 233 unsigned SimpleGVarAbbrev = 0; 234 if (!M->global_empty()) { 235 // Add an abbrev for common globals with no visibility or thread localness. 236 BitCodeAbbrev *Abbv = new BitCodeAbbrev(); 237 Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR)); 238 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 239 Log2_32_Ceil(MaxGlobalType+1))); 240 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 1)); // Constant. 241 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Initializer. 242 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 3)); // Linkage. 243 if (MaxAlignment == 0) // Alignment. 244 Abbv->Add(BitCodeAbbrevOp(0)); 245 else { 246 unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1; 247 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 248 Log2_32_Ceil(MaxEncAlignment+1))); 249 } 250 if (SectionMap.empty()) // Section. 251 Abbv->Add(BitCodeAbbrevOp(0)); 252 else 253 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 254 Log2_32_Ceil(SectionMap.size()))); 255 // Don't bother emitting vis + thread local. 256 SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv); 257 } 258 259 // Emit the global variable information. 260 SmallVector<unsigned, 64> Vals; 261 for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end(); 262 GV != E; ++GV) { 263 unsigned AbbrevToUse = 0; 264 265 // GLOBALVAR: [type, isconst, initid, 266 // linkage, alignment, section, visibility, threadlocal] 267 Vals.push_back(VE.getTypeID(GV->getType())); 268 Vals.push_back(GV->isConstant()); 269 Vals.push_back(GV->isDeclaration() ? 0 : 270 (VE.getValueID(GV->getInitializer()) + 1)); 271 Vals.push_back(getEncodedLinkage(GV)); 272 Vals.push_back(Log2_32(GV->getAlignment())+1); 273 Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0); 274 if (GV->isThreadLocal() || 275 GV->getVisibility() != GlobalValue::DefaultVisibility) { 276 Vals.push_back(getEncodedVisibility(GV)); 277 Vals.push_back(GV->isThreadLocal()); 278 } else { 279 AbbrevToUse = SimpleGVarAbbrev; 280 } 281 282 Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse); 283 Vals.clear(); 284 } 285 286 // Emit the function proto information. 287 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) { 288 // FUNCTION: [type, callingconv, isproto, linkage, alignment, section, 289 // visibility] 290 Vals.push_back(VE.getTypeID(F->getType())); 291 Vals.push_back(F->getCallingConv()); 292 Vals.push_back(F->isDeclaration()); 293 Vals.push_back(getEncodedLinkage(F)); 294 Vals.push_back(Log2_32(F->getAlignment())+1); 295 Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0); 296 Vals.push_back(getEncodedVisibility(F)); 297 298 unsigned AbbrevToUse = 0; 299 Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse); 300 Vals.clear(); 301 } 302} 303 304 305/// WriteModule - Emit the specified module to the bitstream. 306static void WriteModule(const Module *M, BitstreamWriter &Stream) { 307 Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3); 308 309 // Emit the version number if it is non-zero. 310 if (CurVersion) { 311 SmallVector<unsigned, 1> VersionVals; 312 VersionVals.push_back(CurVersion); 313 Stream.EmitRecord(bitc::MODULE_CODE_VERSION, VersionVals); 314 } 315 316 // Analyze the module, enumerating globals, functions, etc. 317 ValueEnumerator VE(M); 318 319 // Emit information describing all of the types in the module. 320 WriteTypeTable(VE, Stream); 321 322 // FIXME: Emit constants. 323 324 // Emit top-level description of module, including target triple, inline asm, 325 // descriptors for global variables, and function prototype info. 326 WriteModuleInfo(M, VE, Stream); 327 328 // Emit the type symbol table information. 329 WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream); 330 Stream.ExitBlock(); 331} 332 333/// WriteBitcodeToFile - Write the specified module to the specified output 334/// stream. 335void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) { 336 std::vector<unsigned char> Buffer; 337 BitstreamWriter Stream(Buffer); 338 339 Buffer.reserve(256*1024); 340 341 // Emit the file header. 342 Stream.Emit((unsigned)'B', 8); 343 Stream.Emit((unsigned)'C', 8); 344 Stream.Emit(0x0, 4); 345 Stream.Emit(0xC, 4); 346 Stream.Emit(0xE, 4); 347 Stream.Emit(0xD, 4); 348 349 // Emit the module. 350 WriteModule(M, Stream); 351 352 // Write the generated bitstream to "Out". 353 Out.write((char*)&Buffer.front(), Buffer.size()); 354} 355