LTOModule.cpp revision 321369
1//===-- LTOModule.cpp - LLVM Link Time Optimizer --------------------------===// 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// This file implements the Link Time Optimization library. This library is 11// intended to be used by linker to optimize code at link time. 12// 13//===----------------------------------------------------------------------===// 14 15#include "llvm/LTO/legacy/LTOModule.h" 16#include "llvm/ADT/Triple.h" 17#include "llvm/Analysis/ObjectUtils.h" 18#include "llvm/Bitcode/BitcodeReader.h" 19#include "llvm/IR/Constants.h" 20#include "llvm/IR/DiagnosticPrinter.h" 21#include "llvm/IR/LLVMContext.h" 22#include "llvm/IR/Mangler.h" 23#include "llvm/IR/Metadata.h" 24#include "llvm/IR/Module.h" 25#include "llvm/MC/MCExpr.h" 26#include "llvm/MC/MCInst.h" 27#include "llvm/MC/MCInstrInfo.h" 28#include "llvm/MC/MCParser/MCAsmParser.h" 29#include "llvm/MC/MCParser/MCTargetAsmParser.h" 30#include "llvm/MC/MCSection.h" 31#include "llvm/MC/MCSubtargetInfo.h" 32#include "llvm/MC/MCSymbol.h" 33#include "llvm/MC/SubtargetFeature.h" 34#include "llvm/Object/IRObjectFile.h" 35#include "llvm/Object/ObjectFile.h" 36#include "llvm/Support/FileSystem.h" 37#include "llvm/Support/Host.h" 38#include "llvm/Support/MemoryBuffer.h" 39#include "llvm/Support/Path.h" 40#include "llvm/Support/SourceMgr.h" 41#include "llvm/Support/TargetRegistry.h" 42#include "llvm/Support/TargetSelect.h" 43#include "llvm/Target/TargetLowering.h" 44#include "llvm/Target/TargetLoweringObjectFile.h" 45#include "llvm/Target/TargetRegisterInfo.h" 46#include "llvm/Target/TargetSubtargetInfo.h" 47#include "llvm/Transforms/Utils/GlobalStatus.h" 48#include <system_error> 49using namespace llvm; 50using namespace llvm::object; 51 52LTOModule::LTOModule(std::unique_ptr<Module> M, MemoryBufferRef MBRef, 53 llvm::TargetMachine *TM) 54 : Mod(std::move(M)), MBRef(MBRef), _target(TM) { 55 SymTab.addModule(Mod.get()); 56} 57 58LTOModule::~LTOModule() {} 59 60/// isBitcodeFile - Returns 'true' if the file (or memory contents) is LLVM 61/// bitcode. 62bool LTOModule::isBitcodeFile(const void *Mem, size_t Length) { 63 ErrorOr<MemoryBufferRef> BCData = IRObjectFile::findBitcodeInMemBuffer( 64 MemoryBufferRef(StringRef((const char *)Mem, Length), "<mem>")); 65 return bool(BCData); 66} 67 68bool LTOModule::isBitcodeFile(StringRef Path) { 69 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 70 MemoryBuffer::getFile(Path); 71 if (!BufferOrErr) 72 return false; 73 74 ErrorOr<MemoryBufferRef> BCData = IRObjectFile::findBitcodeInMemBuffer( 75 BufferOrErr.get()->getMemBufferRef()); 76 return bool(BCData); 77} 78 79bool LTOModule::isThinLTO() { 80 Expected<BitcodeLTOInfo> Result = getBitcodeLTOInfo(MBRef); 81 if (!Result) { 82 logAllUnhandledErrors(Result.takeError(), errs(), ""); 83 return false; 84 } 85 return Result->IsThinLTO; 86} 87 88bool LTOModule::isBitcodeForTarget(MemoryBuffer *Buffer, 89 StringRef TriplePrefix) { 90 ErrorOr<MemoryBufferRef> BCOrErr = 91 IRObjectFile::findBitcodeInMemBuffer(Buffer->getMemBufferRef()); 92 if (!BCOrErr) 93 return false; 94 LLVMContext Context; 95 ErrorOr<std::string> TripleOrErr = 96 expectedToErrorOrAndEmitErrors(Context, getBitcodeTargetTriple(*BCOrErr)); 97 if (!TripleOrErr) 98 return false; 99 return StringRef(*TripleOrErr).startswith(TriplePrefix); 100} 101 102std::string LTOModule::getProducerString(MemoryBuffer *Buffer) { 103 ErrorOr<MemoryBufferRef> BCOrErr = 104 IRObjectFile::findBitcodeInMemBuffer(Buffer->getMemBufferRef()); 105 if (!BCOrErr) 106 return ""; 107 LLVMContext Context; 108 ErrorOr<std::string> ProducerOrErr = expectedToErrorOrAndEmitErrors( 109 Context, getBitcodeProducerString(*BCOrErr)); 110 if (!ProducerOrErr) 111 return ""; 112 return *ProducerOrErr; 113} 114 115ErrorOr<std::unique_ptr<LTOModule>> 116LTOModule::createFromFile(LLVMContext &Context, StringRef path, 117 const TargetOptions &options) { 118 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 119 MemoryBuffer::getFile(path); 120 if (std::error_code EC = BufferOrErr.getError()) { 121 Context.emitError(EC.message()); 122 return EC; 123 } 124 std::unique_ptr<MemoryBuffer> Buffer = std::move(BufferOrErr.get()); 125 return makeLTOModule(Buffer->getMemBufferRef(), options, Context, 126 /* ShouldBeLazy*/ false); 127} 128 129ErrorOr<std::unique_ptr<LTOModule>> 130LTOModule::createFromOpenFile(LLVMContext &Context, int fd, StringRef path, 131 size_t size, const TargetOptions &options) { 132 return createFromOpenFileSlice(Context, fd, path, size, 0, options); 133} 134 135ErrorOr<std::unique_ptr<LTOModule>> 136LTOModule::createFromOpenFileSlice(LLVMContext &Context, int fd, StringRef path, 137 size_t map_size, off_t offset, 138 const TargetOptions &options) { 139 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 140 MemoryBuffer::getOpenFileSlice(fd, path, map_size, offset); 141 if (std::error_code EC = BufferOrErr.getError()) { 142 Context.emitError(EC.message()); 143 return EC; 144 } 145 std::unique_ptr<MemoryBuffer> Buffer = std::move(BufferOrErr.get()); 146 return makeLTOModule(Buffer->getMemBufferRef(), options, Context, 147 /* ShouldBeLazy */ false); 148} 149 150ErrorOr<std::unique_ptr<LTOModule>> 151LTOModule::createFromBuffer(LLVMContext &Context, const void *mem, 152 size_t length, const TargetOptions &options, 153 StringRef path) { 154 StringRef Data((const char *)mem, length); 155 MemoryBufferRef Buffer(Data, path); 156 return makeLTOModule(Buffer, options, Context, /* ShouldBeLazy */ false); 157} 158 159ErrorOr<std::unique_ptr<LTOModule>> 160LTOModule::createInLocalContext(std::unique_ptr<LLVMContext> Context, 161 const void *mem, size_t length, 162 const TargetOptions &options, StringRef path) { 163 StringRef Data((const char *)mem, length); 164 MemoryBufferRef Buffer(Data, path); 165 // If we own a context, we know this is being used only for symbol extraction, 166 // not linking. Be lazy in that case. 167 ErrorOr<std::unique_ptr<LTOModule>> Ret = 168 makeLTOModule(Buffer, options, *Context, /* ShouldBeLazy */ true); 169 if (Ret) 170 (*Ret)->OwnedContext = std::move(Context); 171 return Ret; 172} 173 174static ErrorOr<std::unique_ptr<Module>> 175parseBitcodeFileImpl(MemoryBufferRef Buffer, LLVMContext &Context, 176 bool ShouldBeLazy) { 177 178 // Find the buffer. 179 ErrorOr<MemoryBufferRef> MBOrErr = 180 IRObjectFile::findBitcodeInMemBuffer(Buffer); 181 if (std::error_code EC = MBOrErr.getError()) { 182 Context.emitError(EC.message()); 183 return EC; 184 } 185 186 if (!ShouldBeLazy) { 187 // Parse the full file. 188 return expectedToErrorOrAndEmitErrors(Context, 189 parseBitcodeFile(*MBOrErr, Context)); 190 } 191 192 // Parse lazily. 193 return expectedToErrorOrAndEmitErrors( 194 Context, 195 getLazyBitcodeModule(*MBOrErr, Context, true /*ShouldLazyLoadMetadata*/)); 196} 197 198ErrorOr<std::unique_ptr<LTOModule>> 199LTOModule::makeLTOModule(MemoryBufferRef Buffer, const TargetOptions &options, 200 LLVMContext &Context, bool ShouldBeLazy) { 201 ErrorOr<std::unique_ptr<Module>> MOrErr = 202 parseBitcodeFileImpl(Buffer, Context, ShouldBeLazy); 203 if (std::error_code EC = MOrErr.getError()) 204 return EC; 205 std::unique_ptr<Module> &M = *MOrErr; 206 207 std::string TripleStr = M->getTargetTriple(); 208 if (TripleStr.empty()) 209 TripleStr = sys::getDefaultTargetTriple(); 210 llvm::Triple Triple(TripleStr); 211 212 // find machine architecture for this module 213 std::string errMsg; 214 const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg); 215 if (!march) 216 return std::unique_ptr<LTOModule>(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 = 234 march->createTargetMachine(TripleStr, CPU, FeatureStr, options, None); 235 236 std::unique_ptr<LTOModule> Ret(new LTOModule(std::move(M), Buffer, target)); 237 Ret->parseSymbols(); 238 Ret->parseMetadata(); 239 240 return std::move(Ret); 241} 242 243/// Create a MemoryBuffer from a memory range with an optional name. 244std::unique_ptr<MemoryBuffer> 245LTOModule::makeBuffer(const void *mem, size_t length, StringRef name) { 246 const char *startPtr = (const char*)mem; 247 return MemoryBuffer::getMemBuffer(StringRef(startPtr, length), name, false); 248} 249 250/// objcClassNameFromExpression - Get string that the data pointer points to. 251bool 252LTOModule::objcClassNameFromExpression(const Constant *c, std::string &name) { 253 if (const ConstantExpr *ce = dyn_cast<ConstantExpr>(c)) { 254 Constant *op = ce->getOperand(0); 255 if (GlobalVariable *gvn = dyn_cast<GlobalVariable>(op)) { 256 Constant *cn = gvn->getInitializer(); 257 if (ConstantDataArray *ca = dyn_cast<ConstantDataArray>(cn)) { 258 if (ca->isCString()) { 259 name = (".objc_class_name_" + ca->getAsCString()).str(); 260 return true; 261 } 262 } 263 } 264 } 265 return false; 266} 267 268/// addObjCClass - Parse i386/ppc ObjC class data structure. 269void LTOModule::addObjCClass(const GlobalVariable *clgv) { 270 const ConstantStruct *c = dyn_cast<ConstantStruct>(clgv->getInitializer()); 271 if (!c) return; 272 273 // second slot in __OBJC,__class is pointer to superclass name 274 std::string superclassName; 275 if (objcClassNameFromExpression(c->getOperand(1), superclassName)) { 276 auto IterBool = 277 _undefines.insert(std::make_pair(superclassName, NameAndAttributes())); 278 if (IterBool.second) { 279 NameAndAttributes &info = IterBool.first->second; 280 info.name = IterBool.first->first(); 281 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 282 info.isFunction = false; 283 info.symbol = clgv; 284 } 285 } 286 287 // third slot in __OBJC,__class is pointer to class name 288 std::string className; 289 if (objcClassNameFromExpression(c->getOperand(2), className)) { 290 auto Iter = _defines.insert(className).first; 291 292 NameAndAttributes info; 293 info.name = Iter->first(); 294 info.attributes = LTO_SYMBOL_PERMISSIONS_DATA | 295 LTO_SYMBOL_DEFINITION_REGULAR | LTO_SYMBOL_SCOPE_DEFAULT; 296 info.isFunction = false; 297 info.symbol = clgv; 298 _symbols.push_back(info); 299 } 300} 301 302/// addObjCCategory - Parse i386/ppc ObjC category data structure. 303void LTOModule::addObjCCategory(const GlobalVariable *clgv) { 304 const ConstantStruct *c = dyn_cast<ConstantStruct>(clgv->getInitializer()); 305 if (!c) return; 306 307 // second slot in __OBJC,__category is pointer to target class name 308 std::string targetclassName; 309 if (!objcClassNameFromExpression(c->getOperand(1), targetclassName)) 310 return; 311 312 auto IterBool = 313 _undefines.insert(std::make_pair(targetclassName, NameAndAttributes())); 314 315 if (!IterBool.second) 316 return; 317 318 NameAndAttributes &info = IterBool.first->second; 319 info.name = IterBool.first->first(); 320 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 321 info.isFunction = false; 322 info.symbol = clgv; 323} 324 325/// addObjCClassRef - Parse i386/ppc ObjC class list data structure. 326void LTOModule::addObjCClassRef(const GlobalVariable *clgv) { 327 std::string targetclassName; 328 if (!objcClassNameFromExpression(clgv->getInitializer(), targetclassName)) 329 return; 330 331 auto IterBool = 332 _undefines.insert(std::make_pair(targetclassName, NameAndAttributes())); 333 334 if (!IterBool.second) 335 return; 336 337 NameAndAttributes &info = IterBool.first->second; 338 info.name = IterBool.first->first(); 339 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 340 info.isFunction = false; 341 info.symbol = clgv; 342} 343 344void LTOModule::addDefinedDataSymbol(ModuleSymbolTable::Symbol Sym) { 345 SmallString<64> Buffer; 346 { 347 raw_svector_ostream OS(Buffer); 348 SymTab.printSymbolName(OS, Sym); 349 Buffer.c_str(); 350 } 351 352 const GlobalValue *V = Sym.get<GlobalValue *>(); 353 addDefinedDataSymbol(Buffer, V); 354} 355 356void LTOModule::addDefinedDataSymbol(StringRef Name, const GlobalValue *v) { 357 // Add to list of defined symbols. 358 addDefinedSymbol(Name, v, false); 359 360 if (!v->hasSection() /* || !isTargetDarwin */) 361 return; 362 363 // Special case i386/ppc ObjC data structures in magic sections: 364 // The issue is that the old ObjC object format did some strange 365 // contortions to avoid real linker symbols. For instance, the 366 // ObjC class data structure is allocated statically in the executable 367 // that defines that class. That data structures contains a pointer to 368 // its superclass. But instead of just initializing that part of the 369 // struct to the address of its superclass, and letting the static and 370 // dynamic linkers do the rest, the runtime works by having that field 371 // instead point to a C-string that is the name of the superclass. 372 // At runtime the objc initialization updates that pointer and sets 373 // it to point to the actual super class. As far as the linker 374 // knows it is just a pointer to a string. But then someone wanted the 375 // linker to issue errors at build time if the superclass was not found. 376 // So they figured out a way in mach-o object format to use an absolute 377 // symbols (.objc_class_name_Foo = 0) and a floating reference 378 // (.reference .objc_class_name_Bar) to cause the linker into erroring when 379 // a class was missing. 380 // The following synthesizes the implicit .objc_* symbols for the linker 381 // from the ObjC data structures generated by the front end. 382 383 // special case if this data blob is an ObjC class definition 384 std::string Section = v->getSection(); 385 if (Section.compare(0, 15, "__OBJC,__class,") == 0) { 386 if (const GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) { 387 addObjCClass(gv); 388 } 389 } 390 391 // special case if this data blob is an ObjC category definition 392 else if (Section.compare(0, 18, "__OBJC,__category,") == 0) { 393 if (const GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) { 394 addObjCCategory(gv); 395 } 396 } 397 398 // special case if this data blob is the list of referenced classes 399 else if (Section.compare(0, 18, "__OBJC,__cls_refs,") == 0) { 400 if (const GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) { 401 addObjCClassRef(gv); 402 } 403 } 404} 405 406void LTOModule::addDefinedFunctionSymbol(ModuleSymbolTable::Symbol Sym) { 407 SmallString<64> Buffer; 408 { 409 raw_svector_ostream OS(Buffer); 410 SymTab.printSymbolName(OS, Sym); 411 Buffer.c_str(); 412 } 413 414 const Function *F = cast<Function>(Sym.get<GlobalValue *>()); 415 addDefinedFunctionSymbol(Buffer, F); 416} 417 418void LTOModule::addDefinedFunctionSymbol(StringRef Name, const Function *F) { 419 // add to list of defined symbols 420 addDefinedSymbol(Name, F, true); 421} 422 423void LTOModule::addDefinedSymbol(StringRef Name, const GlobalValue *def, 424 bool isFunction) { 425 // set alignment part log2() can have rounding errors 426 uint32_t align = def->getAlignment(); 427 uint32_t attr = align ? countTrailingZeros(align) : 0; 428 429 // set permissions part 430 if (isFunction) { 431 attr |= LTO_SYMBOL_PERMISSIONS_CODE; 432 } else { 433 const GlobalVariable *gv = dyn_cast<GlobalVariable>(def); 434 if (gv && gv->isConstant()) 435 attr |= LTO_SYMBOL_PERMISSIONS_RODATA; 436 else 437 attr |= LTO_SYMBOL_PERMISSIONS_DATA; 438 } 439 440 // set definition part 441 if (def->hasWeakLinkage() || def->hasLinkOnceLinkage()) 442 attr |= LTO_SYMBOL_DEFINITION_WEAK; 443 else if (def->hasCommonLinkage()) 444 attr |= LTO_SYMBOL_DEFINITION_TENTATIVE; 445 else 446 attr |= LTO_SYMBOL_DEFINITION_REGULAR; 447 448 // set scope part 449 if (def->hasLocalLinkage()) 450 // Ignore visibility if linkage is local. 451 attr |= LTO_SYMBOL_SCOPE_INTERNAL; 452 else if (def->hasHiddenVisibility()) 453 attr |= LTO_SYMBOL_SCOPE_HIDDEN; 454 else if (def->hasProtectedVisibility()) 455 attr |= LTO_SYMBOL_SCOPE_PROTECTED; 456 else if (canBeOmittedFromSymbolTable(def)) 457 attr |= LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN; 458 else 459 attr |= LTO_SYMBOL_SCOPE_DEFAULT; 460 461 if (def->hasComdat()) 462 attr |= LTO_SYMBOL_COMDAT; 463 464 if (isa<GlobalAlias>(def)) 465 attr |= LTO_SYMBOL_ALIAS; 466 467 auto Iter = _defines.insert(Name).first; 468 469 // fill information structure 470 NameAndAttributes info; 471 StringRef NameRef = Iter->first(); 472 info.name = NameRef; 473 assert(NameRef.data()[NameRef.size()] == '\0'); 474 info.attributes = attr; 475 info.isFunction = isFunction; 476 info.symbol = def; 477 478 // add to table of symbols 479 _symbols.push_back(info); 480} 481 482/// addAsmGlobalSymbol - Add a global symbol from module-level ASM to the 483/// defined list. 484void LTOModule::addAsmGlobalSymbol(StringRef name, 485 lto_symbol_attributes scope) { 486 auto IterBool = _defines.insert(name); 487 488 // only add new define if not already defined 489 if (!IterBool.second) 490 return; 491 492 NameAndAttributes &info = _undefines[IterBool.first->first()]; 493 494 if (info.symbol == nullptr) { 495 // FIXME: This is trying to take care of module ASM like this: 496 // 497 // module asm ".zerofill __FOO, __foo, _bar_baz_qux, 0" 498 // 499 // but is gross and its mother dresses it funny. Have the ASM parser give us 500 // more details for this type of situation so that we're not guessing so 501 // much. 502 503 // fill information structure 504 info.name = IterBool.first->first(); 505 info.attributes = 506 LTO_SYMBOL_PERMISSIONS_DATA | LTO_SYMBOL_DEFINITION_REGULAR | scope; 507 info.isFunction = false; 508 info.symbol = nullptr; 509 510 // add to table of symbols 511 _symbols.push_back(info); 512 return; 513 } 514 515 if (info.isFunction) 516 addDefinedFunctionSymbol(info.name, cast<Function>(info.symbol)); 517 else 518 addDefinedDataSymbol(info.name, info.symbol); 519 520 _symbols.back().attributes &= ~LTO_SYMBOL_SCOPE_MASK; 521 _symbols.back().attributes |= scope; 522} 523 524/// addAsmGlobalSymbolUndef - Add a global symbol from module-level ASM to the 525/// undefined list. 526void LTOModule::addAsmGlobalSymbolUndef(StringRef name) { 527 auto IterBool = _undefines.insert(std::make_pair(name, NameAndAttributes())); 528 529 _asm_undefines.push_back(IterBool.first->first()); 530 531 // we already have the symbol 532 if (!IterBool.second) 533 return; 534 535 uint32_t attr = LTO_SYMBOL_DEFINITION_UNDEFINED; 536 attr |= LTO_SYMBOL_SCOPE_DEFAULT; 537 NameAndAttributes &info = IterBool.first->second; 538 info.name = IterBool.first->first(); 539 info.attributes = attr; 540 info.isFunction = false; 541 info.symbol = nullptr; 542} 543 544/// Add a symbol which isn't defined just yet to a list to be resolved later. 545void LTOModule::addPotentialUndefinedSymbol(ModuleSymbolTable::Symbol Sym, 546 bool isFunc) { 547 SmallString<64> name; 548 { 549 raw_svector_ostream OS(name); 550 SymTab.printSymbolName(OS, Sym); 551 name.c_str(); 552 } 553 554 auto IterBool = _undefines.insert(std::make_pair(name, NameAndAttributes())); 555 556 // we already have the symbol 557 if (!IterBool.second) 558 return; 559 560 NameAndAttributes &info = IterBool.first->second; 561 562 info.name = IterBool.first->first(); 563 564 const GlobalValue *decl = Sym.dyn_cast<GlobalValue *>(); 565 566 if (decl->hasExternalWeakLinkage()) 567 info.attributes = LTO_SYMBOL_DEFINITION_WEAKUNDEF; 568 else 569 info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; 570 571 info.isFunction = isFunc; 572 info.symbol = decl; 573} 574 575void LTOModule::parseSymbols() { 576 for (auto Sym : SymTab.symbols()) { 577 auto *GV = Sym.dyn_cast<GlobalValue *>(); 578 uint32_t Flags = SymTab.getSymbolFlags(Sym); 579 if (Flags & object::BasicSymbolRef::SF_FormatSpecific) 580 continue; 581 582 bool IsUndefined = Flags & object::BasicSymbolRef::SF_Undefined; 583 584 if (!GV) { 585 SmallString<64> Buffer; 586 { 587 raw_svector_ostream OS(Buffer); 588 SymTab.printSymbolName(OS, Sym); 589 Buffer.c_str(); 590 } 591 StringRef Name(Buffer); 592 593 if (IsUndefined) 594 addAsmGlobalSymbolUndef(Name); 595 else if (Flags & object::BasicSymbolRef::SF_Global) 596 addAsmGlobalSymbol(Name, LTO_SYMBOL_SCOPE_DEFAULT); 597 else 598 addAsmGlobalSymbol(Name, LTO_SYMBOL_SCOPE_INTERNAL); 599 continue; 600 } 601 602 auto *F = dyn_cast<Function>(GV); 603 if (IsUndefined) { 604 addPotentialUndefinedSymbol(Sym, F != nullptr); 605 continue; 606 } 607 608 if (F) { 609 addDefinedFunctionSymbol(Sym); 610 continue; 611 } 612 613 if (isa<GlobalVariable>(GV)) { 614 addDefinedDataSymbol(Sym); 615 continue; 616 } 617 618 assert(isa<GlobalAlias>(GV)); 619 addDefinedDataSymbol(Sym); 620 } 621 622 // make symbols for all undefines 623 for (StringMap<NameAndAttributes>::iterator u =_undefines.begin(), 624 e = _undefines.end(); u != e; ++u) { 625 // If this symbol also has a definition, then don't make an undefine because 626 // it is a tentative definition. 627 if (_defines.count(u->getKey())) continue; 628 NameAndAttributes info = u->getValue(); 629 _symbols.push_back(info); 630 } 631} 632 633/// parseMetadata - Parse metadata from the module 634void LTOModule::parseMetadata() { 635 raw_string_ostream OS(LinkerOpts); 636 637 // Linker Options 638 if (NamedMDNode *LinkerOptions = 639 getModule().getNamedMetadata("llvm.linker.options")) { 640 for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) { 641 MDNode *MDOptions = LinkerOptions->getOperand(i); 642 for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) { 643 MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii)); 644 OS << " " << MDOption->getString(); 645 } 646 } 647 } 648 649 // Globals - we only need to do this for COFF. 650 const Triple TT(_target->getTargetTriple()); 651 if (!TT.isOSBinFormatCOFF()) 652 return; 653 Mangler M; 654 for (const NameAndAttributes &Sym : _symbols) { 655 if (!Sym.symbol) 656 continue; 657 emitLinkerFlagsForGlobalCOFF(OS, Sym.symbol, TT, M); 658 } 659 660 // Add other interesting metadata here. 661} 662