LTOModule.cpp revision 288943
133965Sjdp//===-- LTOModule.cpp - LLVM Link Time Optimizer --------------------------===// 278828Sobrien// 333965Sjdp// The LLVM Compiler Infrastructure 433965Sjdp// 533965Sjdp// This file is distributed under the University of Illinois Open Source 633965Sjdp// License. See LICENSE.TXT for details. 733965Sjdp// 833965Sjdp//===----------------------------------------------------------------------===// 933965Sjdp// 1033965Sjdp// This file implements the Link Time Optimization library. This library is 1133965Sjdp// intended to be used by linker to optimize code at link time. 1233965Sjdp// 1333965Sjdp//===----------------------------------------------------------------------===// 1433965Sjdp 1533965Sjdp#include "llvm/LTO/LTOModule.h" 1633965Sjdp#include "llvm/ADT/Triple.h" 1777298Sobrien#include "llvm/Bitcode/ReaderWriter.h" 1877298Sobrien#include "llvm/CodeGen/Analysis.h" 1977298Sobrien#include "llvm/IR/Constants.h" 2033965Sjdp#include "llvm/IR/DiagnosticPrinter.h" 2133965Sjdp#include "llvm/IR/LLVMContext.h" 2233965Sjdp#include "llvm/IR/Mangler.h" 2333965Sjdp#include "llvm/IR/Metadata.h" 2433965Sjdp#include "llvm/IR/Module.h" 2533965Sjdp#include "llvm/MC/MCExpr.h" 2633965Sjdp#include "llvm/MC/MCInst.h" 2733965Sjdp#include "llvm/MC/MCInstrInfo.h" 2833965Sjdp#include "llvm/MC/MCParser/MCAsmParser.h" 2933965Sjdp#include "llvm/MC/MCSection.h" 3033965Sjdp#include "llvm/MC/MCSubtargetInfo.h" 3133965Sjdp#include "llvm/MC/MCSymbol.h" 3233965Sjdp#include "llvm/MC/MCTargetAsmParser.h" 3333965Sjdp#include "llvm/MC/SubtargetFeature.h" 3433965Sjdp#include "llvm/Object/IRObjectFile.h" 3533965Sjdp#include "llvm/Object/ObjectFile.h" 3633965Sjdp#include "llvm/Support/CommandLine.h" 3733965Sjdp#include "llvm/Support/FileSystem.h" 3833965Sjdp#include "llvm/Support/Host.h" 3933965Sjdp#include "llvm/Support/MemoryBuffer.h" 4033965Sjdp#include "llvm/Support/Path.h" 4133965Sjdp#include "llvm/Support/SourceMgr.h" 4233965Sjdp#include "llvm/Support/TargetRegistry.h" 4333965Sjdp#include "llvm/Support/TargetSelect.h" 4433965Sjdp#include "llvm/Target/TargetLowering.h" 4533965Sjdp#include "llvm/Target/TargetLoweringObjectFile.h" 4633965Sjdp#include "llvm/Target/TargetRegisterInfo.h" 4733965Sjdp#include "llvm/Target/TargetSubtargetInfo.h" 4833965Sjdp#include "llvm/Transforms/Utils/GlobalStatus.h" 4933965Sjdp#include <system_error> 5033965Sjdpusing namespace llvm; 5133965Sjdpusing namespace llvm::object; 5233965Sjdp 5333965SjdpLTOModule::LTOModule(std::unique_ptr<object::IRObjectFile> Obj, 5433965Sjdp llvm::TargetMachine *TM) 5533965Sjdp : IRFile(std::move(Obj)), _target(TM) {} 5633965Sjdp 5733965SjdpLTOModule::LTOModule(std::unique_ptr<object::IRObjectFile> Obj, 58130561Sobrien llvm::TargetMachine *TM, 59130561Sobrien std::unique_ptr<LLVMContext> Context) 60130561Sobrien : OwnedContext(std::move(Context)), IRFile(std::move(Obj)), _target(TM) {} 61130561Sobrien 62130561SobrienLTOModule::~LTOModule() {} 63130561Sobrien 64130561Sobrien/// isBitcodeFile - Returns 'true' if the file (or memory contents) is LLVM 65130561Sobrien/// bitcode. 66130561Sobrienbool LTOModule::isBitcodeFile(const void *Mem, size_t Length) { 67 ErrorOr<MemoryBufferRef> BCData = IRObjectFile::findBitcodeInMemBuffer( 68 MemoryBufferRef(StringRef((const char *)Mem, Length), "<mem>")); 69 return bool(BCData); 70} 71 72bool LTOModule::isBitcodeFile(const char *Path) { 73 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 74 MemoryBuffer::getFile(Path); 75 if (!BufferOrErr) 76 return false; 77 78 ErrorOr<MemoryBufferRef> BCData = IRObjectFile::findBitcodeInMemBuffer( 79 BufferOrErr.get()->getMemBufferRef()); 80 return bool(BCData); 81} 82 83bool LTOModule::isBitcodeForTarget(MemoryBuffer *Buffer, 84 StringRef TriplePrefix) { 85 ErrorOr<MemoryBufferRef> BCOrErr = 86 IRObjectFile::findBitcodeInMemBuffer(Buffer->getMemBufferRef()); 87 if (!BCOrErr) 88 return false; 89 LLVMContext Context; 90 std::string Triple = getBitcodeTargetTriple(*BCOrErr, Context); 91 return StringRef(Triple).startswith(TriplePrefix); 92} 93 94LTOModule *LTOModule::createFromFile(const char *path, TargetOptions options, 95 std::string &errMsg) { 96 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 97 MemoryBuffer::getFile(path); 98 if (std::error_code EC = BufferOrErr.getError()) { 99 errMsg = EC.message(); 100 return nullptr; 101 } 102 std::unique_ptr<MemoryBuffer> Buffer = std::move(BufferOrErr.get()); 103 return makeLTOModule(Buffer->getMemBufferRef(), options, errMsg, 104 &getGlobalContext()); 105} 106 107LTOModule *LTOModule::createFromOpenFile(int fd, const char *path, size_t size, 108 TargetOptions options, 109 std::string &errMsg) { 110 return createFromOpenFileSlice(fd, path, size, 0, options, errMsg); 111} 112 113LTOModule *LTOModule::createFromOpenFileSlice(int fd, const char *path, 114 size_t map_size, off_t offset, 115 TargetOptions options, 116 std::string &errMsg) { 117 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 118 MemoryBuffer::getOpenFileSlice(fd, path, map_size, offset); 119 if (std::error_code EC = BufferOrErr.getError()) { 120 errMsg = EC.message(); 121 return nullptr; 122 } 123 std::unique_ptr<MemoryBuffer> Buffer = std::move(BufferOrErr.get()); 124 return makeLTOModule(Buffer->getMemBufferRef(), options, errMsg, 125 &getGlobalContext()); 126} 127 128LTOModule *LTOModule::createFromBuffer(const void *mem, size_t length, 129 TargetOptions options, 130 std::string &errMsg, StringRef path) { 131 return createInContext(mem, length, options, errMsg, path, 132 &getGlobalContext()); 133} 134 135LTOModule *LTOModule::createInLocalContext(const void *mem, size_t length, 136 TargetOptions options, 137 std::string &errMsg, 138 StringRef path) { 139 return createInContext(mem, length, options, errMsg, path, nullptr); 140} 141 142LTOModule *LTOModule::createInContext(const void *mem, size_t length, 143 TargetOptions options, 144 std::string &errMsg, StringRef path, 145 LLVMContext *Context) { 146 StringRef Data((const char *)mem, length); 147 MemoryBufferRef Buffer(Data, path); 148 return makeLTOModule(Buffer, options, errMsg, Context); 149} 150 151static std::unique_ptr<Module> parseBitcodeFileImpl(MemoryBufferRef Buffer, 152 LLVMContext &Context, 153 bool ShouldBeLazy, 154 std::string &ErrMsg) { 155 156 // Find the buffer. 157 ErrorOr<MemoryBufferRef> MBOrErr = 158 IRObjectFile::findBitcodeInMemBuffer(Buffer); 159 if (std::error_code EC = MBOrErr.getError()) { 160 ErrMsg = EC.message(); 161 return nullptr; 162 } 163 164 std::function<void(const DiagnosticInfo &)> DiagnosticHandler = 165 [&ErrMsg](const DiagnosticInfo &DI) { 166 raw_string_ostream Stream(ErrMsg); 167 DiagnosticPrinterRawOStream DP(Stream); 168 DI.print(DP); 169 }; 170 171 if (!ShouldBeLazy) { 172 // Parse the full file. 173 ErrorOr<std::unique_ptr<Module>> M = 174 parseBitcodeFile(*MBOrErr, Context, DiagnosticHandler); 175 if (!M) 176 return nullptr; 177 return std::move(*M); 178 } 179 180 // Parse lazily. 181 std::unique_ptr<MemoryBuffer> LightweightBuf = 182 MemoryBuffer::getMemBuffer(*MBOrErr, false); 183 ErrorOr<std::unique_ptr<Module>> M = 184 getLazyBitcodeModule(std::move(LightweightBuf), Context, 185 DiagnosticHandler, true /*ShouldLazyLoadMetadata*/); 186 if (!M) 187 return nullptr; 188 return std::move(*M); 189} 190 191LTOModule *LTOModule::makeLTOModule(MemoryBufferRef Buffer, 192 TargetOptions options, std::string &errMsg, 193 LLVMContext *Context) { 194 std::unique_ptr<LLVMContext> OwnedContext; 195 if (!Context) { 196 OwnedContext = llvm::make_unique<LLVMContext>(); 197 Context = OwnedContext.get(); 198 } 199 200 // If we own a context, we know this is being used only for symbol 201 // extraction, not linking. Be lazy in that case. 202 std::unique_ptr<Module> M = parseBitcodeFileImpl( 203 Buffer, *Context, 204 /* ShouldBeLazy */ static_cast<bool>(OwnedContext), errMsg); 205 if (!M) 206 return nullptr; 207 208 std::string TripleStr = M->getTargetTriple(); 209 if (TripleStr.empty()) 210 TripleStr = sys::getDefaultTargetTriple(); 211 llvm::Triple Triple(TripleStr); 212 213 // find machine architecture for this module 214 const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg); 215 if (!march) 216 return nullptr; 217 218 // construct LTOModule, hand over ownership of module and target 219 SubtargetFeatures Features; 220 Features.getDefaultSubtargetFeatures(Triple); 221 std::string FeatureStr = Features.getString(); 222 // Set a default CPU for Darwin triples. 223 std::string CPU; 224 if (Triple.isOSDarwin()) { 225 if (Triple.getArch() == llvm::Triple::x86_64) 226 CPU = "core2"; 227 else if (Triple.getArch() == llvm::Triple::x86) 228 CPU = "yonah"; 229 else if (Triple.getArch() == llvm::Triple::aarch64) 230 CPU = "cyclone"; 231 } 232 233 TargetMachine *target = march->createTargetMachine(TripleStr, CPU, FeatureStr, 234 options); 235 M->setDataLayout(*target->getDataLayout()); 236 237 std::unique_ptr<object::IRObjectFile> IRObj( 238 new object::IRObjectFile(Buffer, std::move(M))); 239 240 LTOModule *Ret; 241 if (OwnedContext) 242 Ret = new LTOModule(std::move(IRObj), target, std::move(OwnedContext)); 243 else 244 Ret = new LTOModule(std::move(IRObj), target); 245 246 if (Ret->parseSymbols(errMsg)) { 247 delete Ret; 248 return nullptr; 249 } 250 251 Ret->parseMetadata(); 252 253 return Ret; 254} 255 256/// Create a MemoryBuffer from a memory range with an optional name. 257std::unique_ptr<MemoryBuffer> 258LTOModule::makeBuffer(const void *mem, size_t length, StringRef name) { 259 const char *startPtr = (const char*)mem; 260 return MemoryBuffer::getMemBuffer(StringRef(startPtr, length), name, false); 261} 262 263/// objcClassNameFromExpression - Get string that the data pointer points to. 264bool 265LTOModule::objcClassNameFromExpression(const Constant *c, std::string &name) { 266 if (const ConstantExpr *ce = dyn_cast<ConstantExpr>(c)) { 267 Constant *op = ce->getOperand(0); 268 if (GlobalVariable *gvn = dyn_cast<GlobalVariable>(op)) { 269 Constant *cn = gvn->getInitializer(); 270 if (ConstantDataArray *ca = dyn_cast<ConstantDataArray>(cn)) { 271 if (ca->isCString()) { 272 name = (".objc_class_name_" + ca->getAsCString()).str(); 273 return true; 274 } 275 } 276 } 277 } 278 return false; 279} 280 281/// addObjCClass - Parse i386/ppc ObjC class data structure. 282void LTOModule::addObjCClass(const GlobalVariable *clgv) { 283 const ConstantStruct *c = dyn_cast<ConstantStruct>(clgv->getInitializer()); 284 if (!c) return; 285 286 // second slot in __OBJC,__class is pointer to superclass name 287 std::string superclassName; 288 if (objcClassNameFromExpression(c->getOperand(1), superclassName)) { 289 auto IterBool = 290 _undefines.insert(std::make_pair(superclassName, NameAndAttributes())); 291 if (IterBool.second) { 292 NameAndAttributes &info = IterBool.first->second; 293 info.name = IterBool.first->first().data(); 294 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 295 info.isFunction = false; 296 info.symbol = clgv; 297 } 298 } 299 300 // third slot in __OBJC,__class is pointer to class name 301 std::string className; 302 if (objcClassNameFromExpression(c->getOperand(2), className)) { 303 auto Iter = _defines.insert(className).first; 304 305 NameAndAttributes info; 306 info.name = Iter->first().data(); 307 info.attributes = LTO_SYMBOL_PERMISSIONS_DATA | 308 LTO_SYMBOL_DEFINITION_REGULAR | LTO_SYMBOL_SCOPE_DEFAULT; 309 info.isFunction = false; 310 info.symbol = clgv; 311 _symbols.push_back(info); 312 } 313} 314 315/// addObjCCategory - Parse i386/ppc ObjC category data structure. 316void LTOModule::addObjCCategory(const GlobalVariable *clgv) { 317 const ConstantStruct *c = dyn_cast<ConstantStruct>(clgv->getInitializer()); 318 if (!c) return; 319 320 // second slot in __OBJC,__category is pointer to target class name 321 std::string targetclassName; 322 if (!objcClassNameFromExpression(c->getOperand(1), targetclassName)) 323 return; 324 325 auto IterBool = 326 _undefines.insert(std::make_pair(targetclassName, NameAndAttributes())); 327 328 if (!IterBool.second) 329 return; 330 331 NameAndAttributes &info = IterBool.first->second; 332 info.name = IterBool.first->first().data(); 333 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 334 info.isFunction = false; 335 info.symbol = clgv; 336} 337 338/// addObjCClassRef - Parse i386/ppc ObjC class list data structure. 339void LTOModule::addObjCClassRef(const GlobalVariable *clgv) { 340 std::string targetclassName; 341 if (!objcClassNameFromExpression(clgv->getInitializer(), targetclassName)) 342 return; 343 344 auto IterBool = 345 _undefines.insert(std::make_pair(targetclassName, NameAndAttributes())); 346 347 if (!IterBool.second) 348 return; 349 350 NameAndAttributes &info = IterBool.first->second; 351 info.name = IterBool.first->first().data(); 352 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 353 info.isFunction = false; 354 info.symbol = clgv; 355} 356 357void LTOModule::addDefinedDataSymbol(const object::BasicSymbolRef &Sym) { 358 SmallString<64> Buffer; 359 { 360 raw_svector_ostream OS(Buffer); 361 Sym.printName(OS); 362 } 363 364 const GlobalValue *V = IRFile->getSymbolGV(Sym.getRawDataRefImpl()); 365 addDefinedDataSymbol(Buffer.c_str(), V); 366} 367 368void LTOModule::addDefinedDataSymbol(const char *Name, const GlobalValue *v) { 369 // Add to list of defined symbols. 370 addDefinedSymbol(Name, v, false); 371 372 if (!v->hasSection() /* || !isTargetDarwin */) 373 return; 374 375 // Special case i386/ppc ObjC data structures in magic sections: 376 // The issue is that the old ObjC object format did some strange 377 // contortions to avoid real linker symbols. For instance, the 378 // ObjC class data structure is allocated statically in the executable 379 // that defines that class. That data structures contains a pointer to 380 // its superclass. But instead of just initializing that part of the 381 // struct to the address of its superclass, and letting the static and 382 // dynamic linkers do the rest, the runtime works by having that field 383 // instead point to a C-string that is the name of the superclass. 384 // At runtime the objc initialization updates that pointer and sets 385 // it to point to the actual super class. As far as the linker 386 // knows it is just a pointer to a string. But then someone wanted the 387 // linker to issue errors at build time if the superclass was not found. 388 // So they figured out a way in mach-o object format to use an absolute 389 // symbols (.objc_class_name_Foo = 0) and a floating reference 390 // (.reference .objc_class_name_Bar) to cause the linker into erroring when 391 // a class was missing. 392 // The following synthesizes the implicit .objc_* symbols for the linker 393 // from the ObjC data structures generated by the front end. 394 395 // special case if this data blob is an ObjC class definition 396 std::string Section = v->getSection(); 397 if (Section.compare(0, 15, "__OBJC,__class,") == 0) { 398 if (const GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) { 399 addObjCClass(gv); 400 } 401 } 402 403 // special case if this data blob is an ObjC category definition 404 else if (Section.compare(0, 18, "__OBJC,__category,") == 0) { 405 if (const GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) { 406 addObjCCategory(gv); 407 } 408 } 409 410 // special case if this data blob is the list of referenced classes 411 else if (Section.compare(0, 18, "__OBJC,__cls_refs,") == 0) { 412 if (const GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) { 413 addObjCClassRef(gv); 414 } 415 } 416} 417 418void LTOModule::addDefinedFunctionSymbol(const object::BasicSymbolRef &Sym) { 419 SmallString<64> Buffer; 420 { 421 raw_svector_ostream OS(Buffer); 422 Sym.printName(OS); 423 } 424 425 const Function *F = 426 cast<Function>(IRFile->getSymbolGV(Sym.getRawDataRefImpl())); 427 addDefinedFunctionSymbol(Buffer.c_str(), F); 428} 429 430void LTOModule::addDefinedFunctionSymbol(const char *Name, const Function *F) { 431 // add to list of defined symbols 432 addDefinedSymbol(Name, F, true); 433} 434 435void LTOModule::addDefinedSymbol(const char *Name, const GlobalValue *def, 436 bool isFunction) { 437 // set alignment part log2() can have rounding errors 438 uint32_t align = def->getAlignment(); 439 uint32_t attr = align ? countTrailingZeros(align) : 0; 440 441 // set permissions part 442 if (isFunction) { 443 attr |= LTO_SYMBOL_PERMISSIONS_CODE; 444 } else { 445 const GlobalVariable *gv = dyn_cast<GlobalVariable>(def); 446 if (gv && gv->isConstant()) 447 attr |= LTO_SYMBOL_PERMISSIONS_RODATA; 448 else 449 attr |= LTO_SYMBOL_PERMISSIONS_DATA; 450 } 451 452 // set definition part 453 if (def->hasWeakLinkage() || def->hasLinkOnceLinkage()) 454 attr |= LTO_SYMBOL_DEFINITION_WEAK; 455 else if (def->hasCommonLinkage()) 456 attr |= LTO_SYMBOL_DEFINITION_TENTATIVE; 457 else 458 attr |= LTO_SYMBOL_DEFINITION_REGULAR; 459 460 // set scope part 461 if (def->hasLocalLinkage()) 462 // Ignore visibility if linkage is local. 463 attr |= LTO_SYMBOL_SCOPE_INTERNAL; 464 else if (def->hasHiddenVisibility()) 465 attr |= LTO_SYMBOL_SCOPE_HIDDEN; 466 else if (def->hasProtectedVisibility()) 467 attr |= LTO_SYMBOL_SCOPE_PROTECTED; 468 else if (canBeOmittedFromSymbolTable(def)) 469 attr |= LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN; 470 else 471 attr |= LTO_SYMBOL_SCOPE_DEFAULT; 472 473 if (def->hasComdat()) 474 attr |= LTO_SYMBOL_COMDAT; 475 476 if (isa<GlobalAlias>(def)) 477 attr |= LTO_SYMBOL_ALIAS; 478 479 auto Iter = _defines.insert(Name).first; 480 481 // fill information structure 482 NameAndAttributes info; 483 StringRef NameRef = Iter->first(); 484 info.name = NameRef.data(); 485 assert(info.name[NameRef.size()] == '\0'); 486 info.attributes = attr; 487 info.isFunction = isFunction; 488 info.symbol = def; 489 490 // add to table of symbols 491 _symbols.push_back(info); 492} 493 494/// addAsmGlobalSymbol - Add a global symbol from module-level ASM to the 495/// defined list. 496void LTOModule::addAsmGlobalSymbol(const char *name, 497 lto_symbol_attributes scope) { 498 auto IterBool = _defines.insert(name); 499 500 // only add new define if not already defined 501 if (!IterBool.second) 502 return; 503 504 NameAndAttributes &info = _undefines[IterBool.first->first().data()]; 505 506 if (info.symbol == nullptr) { 507 // FIXME: This is trying to take care of module ASM like this: 508 // 509 // module asm ".zerofill __FOO, __foo, _bar_baz_qux, 0" 510 // 511 // but is gross and its mother dresses it funny. Have the ASM parser give us 512 // more details for this type of situation so that we're not guessing so 513 // much. 514 515 // fill information structure 516 info.name = IterBool.first->first().data(); 517 info.attributes = 518 LTO_SYMBOL_PERMISSIONS_DATA | LTO_SYMBOL_DEFINITION_REGULAR | scope; 519 info.isFunction = false; 520 info.symbol = nullptr; 521 522 // add to table of symbols 523 _symbols.push_back(info); 524 return; 525 } 526 527 if (info.isFunction) 528 addDefinedFunctionSymbol(info.name, cast<Function>(info.symbol)); 529 else 530 addDefinedDataSymbol(info.name, info.symbol); 531 532 _symbols.back().attributes &= ~LTO_SYMBOL_SCOPE_MASK; 533 _symbols.back().attributes |= scope; 534} 535 536/// addAsmGlobalSymbolUndef - Add a global symbol from module-level ASM to the 537/// undefined list. 538void LTOModule::addAsmGlobalSymbolUndef(const char *name) { 539 auto IterBool = _undefines.insert(std::make_pair(name, NameAndAttributes())); 540 541 _asm_undefines.push_back(IterBool.first->first().data()); 542 543 // we already have the symbol 544 if (!IterBool.second) 545 return; 546 547 uint32_t attr = LTO_SYMBOL_DEFINITION_UNDEFINED; 548 attr |= LTO_SYMBOL_SCOPE_DEFAULT; 549 NameAndAttributes &info = IterBool.first->second; 550 info.name = IterBool.first->first().data(); 551 info.attributes = attr; 552 info.isFunction = false; 553 info.symbol = nullptr; 554} 555 556/// Add a symbol which isn't defined just yet to a list to be resolved later. 557void LTOModule::addPotentialUndefinedSymbol(const object::BasicSymbolRef &Sym, 558 bool isFunc) { 559 SmallString<64> name; 560 { 561 raw_svector_ostream OS(name); 562 Sym.printName(OS); 563 } 564 565 auto IterBool = _undefines.insert(std::make_pair(name, NameAndAttributes())); 566 567 // we already have the symbol 568 if (!IterBool.second) 569 return; 570 571 NameAndAttributes &info = IterBool.first->second; 572 573 info.name = IterBool.first->first().data(); 574 575 const GlobalValue *decl = IRFile->getSymbolGV(Sym.getRawDataRefImpl()); 576 577 if (decl->hasExternalWeakLinkage()) 578 info.attributes = LTO_SYMBOL_DEFINITION_WEAKUNDEF; 579 else 580 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 581 582 info.isFunction = isFunc; 583 info.symbol = decl; 584} 585 586/// parseSymbols - Parse the symbols from the module and model-level ASM and add 587/// them to either the defined or undefined lists. 588bool LTOModule::parseSymbols(std::string &errMsg) { 589 for (auto &Sym : IRFile->symbols()) { 590 const GlobalValue *GV = IRFile->getSymbolGV(Sym.getRawDataRefImpl()); 591 uint32_t Flags = Sym.getFlags(); 592 if (Flags & object::BasicSymbolRef::SF_FormatSpecific) 593 continue; 594 595 bool IsUndefined = Flags & object::BasicSymbolRef::SF_Undefined; 596 597 if (!GV) { 598 SmallString<64> Buffer; 599 { 600 raw_svector_ostream OS(Buffer); 601 Sym.printName(OS); 602 } 603 const char *Name = Buffer.c_str(); 604 605 if (IsUndefined) 606 addAsmGlobalSymbolUndef(Name); 607 else if (Flags & object::BasicSymbolRef::SF_Global) 608 addAsmGlobalSymbol(Name, LTO_SYMBOL_SCOPE_DEFAULT); 609 else 610 addAsmGlobalSymbol(Name, LTO_SYMBOL_SCOPE_INTERNAL); 611 continue; 612 } 613 614 auto *F = dyn_cast<Function>(GV); 615 if (IsUndefined) { 616 addPotentialUndefinedSymbol(Sym, F != nullptr); 617 continue; 618 } 619 620 if (F) { 621 addDefinedFunctionSymbol(Sym); 622 continue; 623 } 624 625 if (isa<GlobalVariable>(GV)) { 626 addDefinedDataSymbol(Sym); 627 continue; 628 } 629 630 assert(isa<GlobalAlias>(GV)); 631 addDefinedDataSymbol(Sym); 632 } 633 634 // make symbols for all undefines 635 for (StringMap<NameAndAttributes>::iterator u =_undefines.begin(), 636 e = _undefines.end(); u != e; ++u) { 637 // If this symbol also has a definition, then don't make an undefine because 638 // it is a tentative definition. 639 if (_defines.count(u->getKey())) continue; 640 NameAndAttributes info = u->getValue(); 641 _symbols.push_back(info); 642 } 643 644 return false; 645} 646 647/// parseMetadata - Parse metadata from the module 648void LTOModule::parseMetadata() { 649 raw_string_ostream OS(LinkerOpts); 650 651 // Linker Options 652 if (Metadata *Val = getModule().getModuleFlag("Linker Options")) { 653 MDNode *LinkerOptions = cast<MDNode>(Val); 654 for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) { 655 MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i)); 656 for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) { 657 MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii)); 658 OS << " " << MDOption->getString(); 659 } 660 } 661 } 662 663 // Globals 664 Mangler Mang; 665 for (const NameAndAttributes &Sym : _symbols) { 666 if (!Sym.symbol) 667 continue; 668 _target->getObjFileLowering()->emitLinkerFlagsForGlobal(OS, Sym.symbol, 669 Mang); 670 } 671 672 // Add other interesting metadata here. 673} 674