1 //===- ELFAsmParser.cpp - ELF Assembly Parser -----------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/ADT/StringRef.h" 10 #include "llvm/ADT/StringSwitch.h" 11 #include "llvm/BinaryFormat/ELF.h" 12 #include "llvm/MC/MCAsmInfo.h" 13 #include "llvm/MC/MCContext.h" 14 #include "llvm/MC/MCDirectives.h" 15 #include "llvm/MC/MCExpr.h" 16 #include "llvm/MC/MCParser/MCAsmLexer.h" 17 #include "llvm/MC/MCParser/MCAsmParser.h" 18 #include "llvm/MC/MCParser/MCAsmParserExtension.h" 19 #include "llvm/MC/MCSection.h" 20 #include "llvm/MC/MCSectionELF.h" 21 #include "llvm/MC/MCStreamer.h" 22 #include "llvm/MC/MCSymbol.h" 23 #include "llvm/MC/MCSymbolELF.h" 24 #include "llvm/MC/SectionKind.h" 25 #include "llvm/Support/Casting.h" 26 #include "llvm/Support/MathExtras.h" 27 #include "llvm/Support/SMLoc.h" 28 #include <cassert> 29 #include <cstdint> 30 #include <utility> 31 32 using namespace llvm; 33 34 namespace { 35 36 class ELFAsmParser : public MCAsmParserExtension { 37 template<bool (ELFAsmParser::*HandlerMethod)(StringRef, SMLoc)> 38 void addDirectiveHandler(StringRef Directive) { 39 MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair( 40 this, HandleDirective<ELFAsmParser, HandlerMethod>); 41 42 getParser().addDirectiveHandler(Directive, Handler); 43 } 44 45 bool ParseSectionSwitch(StringRef Section, unsigned Type, unsigned Flags, 46 SectionKind Kind); 47 48 public: 49 ELFAsmParser() { BracketExpressionsSupported = true; } 50 51 void Initialize(MCAsmParser &Parser) override { 52 // Call the base implementation. 53 this->MCAsmParserExtension::Initialize(Parser); 54 55 addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data"); 56 addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text"); 57 addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss"); 58 addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata"); 59 addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata"); 60 addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss"); 61 addDirectiveHandler< 62 &ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel"); 63 addDirectiveHandler< 64 &ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro"); 65 addDirectiveHandler< 66 &ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame"); 67 addDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section"); 68 addDirectiveHandler< 69 &ELFAsmParser::ParseDirectivePushSection>(".pushsection"); 70 addDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection"); 71 addDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size"); 72 addDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous"); 73 addDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type"); 74 addDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident"); 75 addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver"); 76 addDirectiveHandler<&ELFAsmParser::ParseDirectiveVersion>(".version"); 77 addDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref"); 78 addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak"); 79 addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local"); 80 addDirectiveHandler< 81 &ELFAsmParser::ParseDirectiveSymbolAttribute>(".protected"); 82 addDirectiveHandler< 83 &ELFAsmParser::ParseDirectiveSymbolAttribute>(".internal"); 84 addDirectiveHandler< 85 &ELFAsmParser::ParseDirectiveSymbolAttribute>(".hidden"); 86 addDirectiveHandler<&ELFAsmParser::ParseDirectiveSubsection>(".subsection"); 87 addDirectiveHandler<&ELFAsmParser::ParseDirectiveCGProfile>(".cg_profile"); 88 } 89 90 // FIXME: Part of this logic is duplicated in the MCELFStreamer. What is 91 // the best way for us to get access to it? 92 bool ParseSectionDirectiveData(StringRef, SMLoc) { 93 return ParseSectionSwitch(".data", ELF::SHT_PROGBITS, 94 ELF::SHF_WRITE | ELF::SHF_ALLOC, 95 SectionKind::getData()); 96 } 97 bool ParseSectionDirectiveText(StringRef, SMLoc) { 98 return ParseSectionSwitch(".text", ELF::SHT_PROGBITS, 99 ELF::SHF_EXECINSTR | 100 ELF::SHF_ALLOC, SectionKind::getText()); 101 } 102 bool ParseSectionDirectiveBSS(StringRef, SMLoc) { 103 return ParseSectionSwitch(".bss", ELF::SHT_NOBITS, 104 ELF::SHF_WRITE | 105 ELF::SHF_ALLOC, SectionKind::getBSS()); 106 } 107 bool ParseSectionDirectiveRoData(StringRef, SMLoc) { 108 return ParseSectionSwitch(".rodata", ELF::SHT_PROGBITS, 109 ELF::SHF_ALLOC, 110 SectionKind::getReadOnly()); 111 } 112 bool ParseSectionDirectiveTData(StringRef, SMLoc) { 113 return ParseSectionSwitch(".tdata", ELF::SHT_PROGBITS, 114 ELF::SHF_ALLOC | 115 ELF::SHF_TLS | ELF::SHF_WRITE, 116 SectionKind::getThreadData()); 117 } 118 bool ParseSectionDirectiveTBSS(StringRef, SMLoc) { 119 return ParseSectionSwitch(".tbss", ELF::SHT_NOBITS, 120 ELF::SHF_ALLOC | 121 ELF::SHF_TLS | ELF::SHF_WRITE, 122 SectionKind::getThreadBSS()); 123 } 124 bool ParseSectionDirectiveDataRel(StringRef, SMLoc) { 125 return ParseSectionSwitch(".data.rel", ELF::SHT_PROGBITS, 126 ELF::SHF_ALLOC | ELF::SHF_WRITE, 127 SectionKind::getData()); 128 } 129 bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) { 130 return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS, 131 ELF::SHF_ALLOC | 132 ELF::SHF_WRITE, 133 SectionKind::getReadOnlyWithRel()); 134 } 135 bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) { 136 return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS, 137 ELF::SHF_ALLOC | ELF::SHF_WRITE, 138 SectionKind::getData()); 139 } 140 bool ParseDirectivePushSection(StringRef, SMLoc); 141 bool ParseDirectivePopSection(StringRef, SMLoc); 142 bool ParseDirectiveSection(StringRef, SMLoc); 143 bool ParseDirectiveSize(StringRef, SMLoc); 144 bool ParseDirectivePrevious(StringRef, SMLoc); 145 bool ParseDirectiveType(StringRef, SMLoc); 146 bool ParseDirectiveIdent(StringRef, SMLoc); 147 bool ParseDirectiveSymver(StringRef, SMLoc); 148 bool ParseDirectiveVersion(StringRef, SMLoc); 149 bool ParseDirectiveWeakref(StringRef, SMLoc); 150 bool ParseDirectiveSymbolAttribute(StringRef, SMLoc); 151 bool ParseDirectiveSubsection(StringRef, SMLoc); 152 bool ParseDirectiveCGProfile(StringRef, SMLoc); 153 154 private: 155 bool ParseSectionName(StringRef &SectionName); 156 bool ParseSectionArguments(bool IsPush, SMLoc loc); 157 unsigned parseSunStyleSectionFlags(); 158 bool maybeParseSectionType(StringRef &TypeName); 159 bool parseMergeSize(int64_t &Size); 160 bool parseGroup(StringRef &GroupName); 161 bool parseLinkedToSym(MCSymbolELF *&LinkedToSym); 162 bool maybeParseUniqueID(int64_t &UniqueID); 163 }; 164 165 } // end anonymous namespace 166 167 /// ParseDirectiveSymbolAttribute 168 /// ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ] 169 bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) { 170 MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive) 171 .Case(".weak", MCSA_Weak) 172 .Case(".local", MCSA_Local) 173 .Case(".hidden", MCSA_Hidden) 174 .Case(".internal", MCSA_Internal) 175 .Case(".protected", MCSA_Protected) 176 .Default(MCSA_Invalid); 177 assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!"); 178 if (getLexer().isNot(AsmToken::EndOfStatement)) { 179 while (true) { 180 StringRef Name; 181 182 if (getParser().parseIdentifier(Name)) 183 return TokError("expected identifier in directive"); 184 185 MCSymbol *Sym = getContext().getOrCreateSymbol(Name); 186 187 getStreamer().emitSymbolAttribute(Sym, Attr); 188 189 if (getLexer().is(AsmToken::EndOfStatement)) 190 break; 191 192 if (getLexer().isNot(AsmToken::Comma)) 193 return TokError("unexpected token in directive"); 194 Lex(); 195 } 196 } 197 198 Lex(); 199 return false; 200 } 201 202 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type, 203 unsigned Flags, SectionKind Kind) { 204 const MCExpr *Subsection = nullptr; 205 if (getLexer().isNot(AsmToken::EndOfStatement)) { 206 if (getParser().parseExpression(Subsection)) 207 return true; 208 } 209 Lex(); 210 211 getStreamer().SwitchSection(getContext().getELFSection(Section, Type, Flags), 212 Subsection); 213 214 return false; 215 } 216 217 bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) { 218 StringRef Name; 219 if (getParser().parseIdentifier(Name)) 220 return TokError("expected identifier in directive"); 221 MCSymbolELF *Sym = cast<MCSymbolELF>(getContext().getOrCreateSymbol(Name)); 222 223 if (getLexer().isNot(AsmToken::Comma)) 224 return TokError("unexpected token in directive"); 225 Lex(); 226 227 const MCExpr *Expr; 228 if (getParser().parseExpression(Expr)) 229 return true; 230 231 if (getLexer().isNot(AsmToken::EndOfStatement)) 232 return TokError("unexpected token in directive"); 233 Lex(); 234 235 getStreamer().emitELFSize(Sym, Expr); 236 return false; 237 } 238 239 bool ELFAsmParser::ParseSectionName(StringRef &SectionName) { 240 // A section name can contain -, so we cannot just use 241 // parseIdentifier. 242 SMLoc FirstLoc = getLexer().getLoc(); 243 unsigned Size = 0; 244 245 if (getLexer().is(AsmToken::String)) { 246 SectionName = getTok().getIdentifier(); 247 Lex(); 248 return false; 249 } 250 251 while (!getParser().hasPendingError()) { 252 SMLoc PrevLoc = getLexer().getLoc(); 253 if (getLexer().is(AsmToken::Comma) || 254 getLexer().is(AsmToken::EndOfStatement)) 255 break; 256 257 unsigned CurSize; 258 if (getLexer().is(AsmToken::String)) { 259 CurSize = getTok().getIdentifier().size() + 2; 260 Lex(); 261 } else if (getLexer().is(AsmToken::Identifier)) { 262 CurSize = getTok().getIdentifier().size(); 263 Lex(); 264 } else { 265 CurSize = getTok().getString().size(); 266 Lex(); 267 } 268 Size += CurSize; 269 SectionName = StringRef(FirstLoc.getPointer(), Size); 270 271 // Make sure the following token is adjacent. 272 if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer()) 273 break; 274 } 275 if (Size == 0) 276 return true; 277 278 return false; 279 } 280 281 static unsigned parseSectionFlags(StringRef flagsStr, bool *UseLastGroup) { 282 unsigned flags = 0; 283 284 // If a valid numerical value is set for the section flag, use it verbatim 285 if (!flagsStr.getAsInteger(0, flags)) 286 return flags; 287 288 for (char i : flagsStr) { 289 switch (i) { 290 case 'a': 291 flags |= ELF::SHF_ALLOC; 292 break; 293 case 'e': 294 flags |= ELF::SHF_EXCLUDE; 295 break; 296 case 'x': 297 flags |= ELF::SHF_EXECINSTR; 298 break; 299 case 'w': 300 flags |= ELF::SHF_WRITE; 301 break; 302 case 'o': 303 flags |= ELF::SHF_LINK_ORDER; 304 break; 305 case 'M': 306 flags |= ELF::SHF_MERGE; 307 break; 308 case 'S': 309 flags |= ELF::SHF_STRINGS; 310 break; 311 case 'T': 312 flags |= ELF::SHF_TLS; 313 break; 314 case 'c': 315 flags |= ELF::XCORE_SHF_CP_SECTION; 316 break; 317 case 'd': 318 flags |= ELF::XCORE_SHF_DP_SECTION; 319 break; 320 case 'y': 321 flags |= ELF::SHF_ARM_PURECODE; 322 break; 323 case 's': 324 flags |= ELF::SHF_HEX_GPREL; 325 break; 326 case 'G': 327 flags |= ELF::SHF_GROUP; 328 break; 329 case '?': 330 *UseLastGroup = true; 331 break; 332 default: 333 return -1U; 334 } 335 } 336 337 return flags; 338 } 339 340 unsigned ELFAsmParser::parseSunStyleSectionFlags() { 341 unsigned flags = 0; 342 while (getLexer().is(AsmToken::Hash)) { 343 Lex(); // Eat the #. 344 345 if (!getLexer().is(AsmToken::Identifier)) 346 return -1U; 347 348 StringRef flagId = getTok().getIdentifier(); 349 if (flagId == "alloc") 350 flags |= ELF::SHF_ALLOC; 351 else if (flagId == "execinstr") 352 flags |= ELF::SHF_EXECINSTR; 353 else if (flagId == "write") 354 flags |= ELF::SHF_WRITE; 355 else if (flagId == "tls") 356 flags |= ELF::SHF_TLS; 357 else 358 return -1U; 359 360 Lex(); // Eat the flag. 361 362 if (!getLexer().is(AsmToken::Comma)) 363 break; 364 Lex(); // Eat the comma. 365 } 366 return flags; 367 } 368 369 370 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) { 371 getStreamer().PushSection(); 372 373 if (ParseSectionArguments(/*IsPush=*/true, loc)) { 374 getStreamer().PopSection(); 375 return true; 376 } 377 378 return false; 379 } 380 381 bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) { 382 if (!getStreamer().PopSection()) 383 return TokError(".popsection without corresponding .pushsection"); 384 return false; 385 } 386 387 bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) { 388 return ParseSectionArguments(/*IsPush=*/false, loc); 389 } 390 391 bool ELFAsmParser::maybeParseSectionType(StringRef &TypeName) { 392 MCAsmLexer &L = getLexer(); 393 if (L.isNot(AsmToken::Comma)) 394 return false; 395 Lex(); 396 if (L.isNot(AsmToken::At) && L.isNot(AsmToken::Percent) && 397 L.isNot(AsmToken::String)) { 398 if (L.getAllowAtInIdentifier()) 399 return TokError("expected '@<type>', '%<type>' or \"<type>\""); 400 else 401 return TokError("expected '%<type>' or \"<type>\""); 402 } 403 if (!L.is(AsmToken::String)) 404 Lex(); 405 if (L.is(AsmToken::Integer)) { 406 TypeName = getTok().getString(); 407 Lex(); 408 } else if (getParser().parseIdentifier(TypeName)) 409 return TokError("expected identifier in directive"); 410 return false; 411 } 412 413 bool ELFAsmParser::parseMergeSize(int64_t &Size) { 414 if (getLexer().isNot(AsmToken::Comma)) 415 return TokError("expected the entry size"); 416 Lex(); 417 if (getParser().parseAbsoluteExpression(Size)) 418 return true; 419 if (Size <= 0) 420 return TokError("entry size must be positive"); 421 return false; 422 } 423 424 bool ELFAsmParser::parseGroup(StringRef &GroupName) { 425 MCAsmLexer &L = getLexer(); 426 if (L.isNot(AsmToken::Comma)) 427 return TokError("expected group name"); 428 Lex(); 429 if (L.is(AsmToken::Integer)) { 430 GroupName = getTok().getString(); 431 Lex(); 432 } else if (getParser().parseIdentifier(GroupName)) { 433 return TokError("invalid group name"); 434 } 435 if (L.is(AsmToken::Comma)) { 436 Lex(); 437 StringRef Linkage; 438 if (getParser().parseIdentifier(Linkage)) 439 return TokError("invalid linkage"); 440 if (Linkage != "comdat") 441 return TokError("Linkage must be 'comdat'"); 442 } 443 return false; 444 } 445 446 bool ELFAsmParser::parseLinkedToSym(MCSymbolELF *&LinkedToSym) { 447 MCAsmLexer &L = getLexer(); 448 if (L.isNot(AsmToken::Comma)) 449 return TokError("expected linked-to symbol"); 450 Lex(); 451 StringRef Name; 452 SMLoc StartLoc = L.getLoc(); 453 if (getParser().parseIdentifier(Name)) { 454 if (getParser().getTok().getString() == "0") { 455 getParser().Lex(); 456 LinkedToSym = nullptr; 457 return false; 458 } 459 return TokError("invalid linked-to symbol"); 460 } 461 LinkedToSym = dyn_cast_or_null<MCSymbolELF>(getContext().lookupSymbol(Name)); 462 if (!LinkedToSym || !LinkedToSym->isInSection()) 463 return Error(StartLoc, "linked-to symbol is not in a section: " + Name); 464 return false; 465 } 466 467 bool ELFAsmParser::maybeParseUniqueID(int64_t &UniqueID) { 468 MCAsmLexer &L = getLexer(); 469 if (L.isNot(AsmToken::Comma)) 470 return false; 471 Lex(); 472 StringRef UniqueStr; 473 if (getParser().parseIdentifier(UniqueStr)) 474 return TokError("expected identifier in directive"); 475 if (UniqueStr != "unique") 476 return TokError("expected 'unique'"); 477 if (L.isNot(AsmToken::Comma)) 478 return TokError("expected commma"); 479 Lex(); 480 if (getParser().parseAbsoluteExpression(UniqueID)) 481 return true; 482 if (UniqueID < 0) 483 return TokError("unique id must be positive"); 484 if (!isUInt<32>(UniqueID) || UniqueID == ~0U) 485 return TokError("unique id is too large"); 486 return false; 487 } 488 489 static bool hasPrefix(StringRef SectionName, StringRef Prefix) { 490 return SectionName.startswith(Prefix) || SectionName == Prefix.drop_back(); 491 } 492 493 bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) { 494 StringRef SectionName; 495 496 if (ParseSectionName(SectionName)) 497 return TokError("expected identifier in directive"); 498 499 StringRef TypeName; 500 int64_t Size = 0; 501 StringRef GroupName; 502 unsigned Flags = 0; 503 const MCExpr *Subsection = nullptr; 504 bool UseLastGroup = false; 505 MCSymbolELF *LinkedToSym = nullptr; 506 int64_t UniqueID = ~0; 507 508 // Set the defaults first. 509 if (hasPrefix(SectionName, ".rodata.") || SectionName == ".rodata1") 510 Flags |= ELF::SHF_ALLOC; 511 else if (SectionName == ".fini" || SectionName == ".init" || 512 hasPrefix(SectionName, ".text.")) 513 Flags |= ELF::SHF_ALLOC | ELF::SHF_EXECINSTR; 514 else if (hasPrefix(SectionName, ".data.") || SectionName == ".data1" || 515 hasPrefix(SectionName, ".bss.") || 516 hasPrefix(SectionName, ".init_array.") || 517 hasPrefix(SectionName, ".fini_array.") || 518 hasPrefix(SectionName, ".preinit_array.")) 519 Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE; 520 else if (hasPrefix(SectionName, ".tdata.") || 521 hasPrefix(SectionName, ".tbss.")) 522 Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_TLS; 523 524 if (getLexer().is(AsmToken::Comma)) { 525 Lex(); 526 527 if (IsPush && getLexer().isNot(AsmToken::String)) { 528 if (getParser().parseExpression(Subsection)) 529 return true; 530 if (getLexer().isNot(AsmToken::Comma)) 531 goto EndStmt; 532 Lex(); 533 } 534 535 unsigned extraFlags; 536 537 if (getLexer().isNot(AsmToken::String)) { 538 if (!getContext().getAsmInfo()->usesSunStyleELFSectionSwitchSyntax() 539 || getLexer().isNot(AsmToken::Hash)) 540 return TokError("expected string in directive"); 541 extraFlags = parseSunStyleSectionFlags(); 542 } else { 543 StringRef FlagsStr = getTok().getStringContents(); 544 Lex(); 545 extraFlags = parseSectionFlags(FlagsStr, &UseLastGroup); 546 } 547 548 if (extraFlags == -1U) 549 return TokError("unknown flag"); 550 Flags |= extraFlags; 551 552 bool Mergeable = Flags & ELF::SHF_MERGE; 553 bool Group = Flags & ELF::SHF_GROUP; 554 if (Group && UseLastGroup) 555 return TokError("Section cannot specifiy a group name while also acting " 556 "as a member of the last group"); 557 558 if (maybeParseSectionType(TypeName)) 559 return true; 560 561 MCAsmLexer &L = getLexer(); 562 if (TypeName.empty()) { 563 if (Mergeable) 564 return TokError("Mergeable section must specify the type"); 565 if (Group) 566 return TokError("Group section must specify the type"); 567 if (L.isNot(AsmToken::EndOfStatement)) 568 return TokError("unexpected token in directive"); 569 } 570 571 if (Mergeable) 572 if (parseMergeSize(Size)) 573 return true; 574 if (Group) 575 if (parseGroup(GroupName)) 576 return true; 577 if (Flags & ELF::SHF_LINK_ORDER) 578 if (parseLinkedToSym(LinkedToSym)) 579 return true; 580 if (maybeParseUniqueID(UniqueID)) 581 return true; 582 } 583 584 EndStmt: 585 if (getLexer().isNot(AsmToken::EndOfStatement)) 586 return TokError("unexpected token in directive"); 587 Lex(); 588 589 unsigned Type = ELF::SHT_PROGBITS; 590 591 if (TypeName.empty()) { 592 if (SectionName.startswith(".note")) 593 Type = ELF::SHT_NOTE; 594 else if (hasPrefix(SectionName, ".init_array.")) 595 Type = ELF::SHT_INIT_ARRAY; 596 else if (hasPrefix(SectionName, ".bss.")) 597 Type = ELF::SHT_NOBITS; 598 else if (hasPrefix(SectionName, ".tbss.")) 599 Type = ELF::SHT_NOBITS; 600 else if (hasPrefix(SectionName, ".fini_array.")) 601 Type = ELF::SHT_FINI_ARRAY; 602 else if (hasPrefix(SectionName, ".preinit_array.")) 603 Type = ELF::SHT_PREINIT_ARRAY; 604 } else { 605 if (TypeName == "init_array") 606 Type = ELF::SHT_INIT_ARRAY; 607 else if (TypeName == "fini_array") 608 Type = ELF::SHT_FINI_ARRAY; 609 else if (TypeName == "preinit_array") 610 Type = ELF::SHT_PREINIT_ARRAY; 611 else if (TypeName == "nobits") 612 Type = ELF::SHT_NOBITS; 613 else if (TypeName == "progbits") 614 Type = ELF::SHT_PROGBITS; 615 else if (TypeName == "note") 616 Type = ELF::SHT_NOTE; 617 else if (TypeName == "unwind") 618 Type = ELF::SHT_X86_64_UNWIND; 619 else if (TypeName == "llvm_odrtab") 620 Type = ELF::SHT_LLVM_ODRTAB; 621 else if (TypeName == "llvm_linker_options") 622 Type = ELF::SHT_LLVM_LINKER_OPTIONS; 623 else if (TypeName == "llvm_call_graph_profile") 624 Type = ELF::SHT_LLVM_CALL_GRAPH_PROFILE; 625 else if (TypeName == "llvm_dependent_libraries") 626 Type = ELF::SHT_LLVM_DEPENDENT_LIBRARIES; 627 else if (TypeName == "llvm_sympart") 628 Type = ELF::SHT_LLVM_SYMPART; 629 else if (TypeName == "llvm_bb_addr_map") 630 Type = ELF::SHT_LLVM_BB_ADDR_MAP; 631 else if (TypeName.getAsInteger(0, Type)) 632 return TokError("unknown section type"); 633 } 634 635 if (UseLastGroup) { 636 MCSectionSubPair CurrentSection = getStreamer().getCurrentSection(); 637 if (const MCSectionELF *Section = 638 cast_or_null<MCSectionELF>(CurrentSection.first)) 639 if (const MCSymbol *Group = Section->getGroup()) { 640 GroupName = Group->getName(); 641 Flags |= ELF::SHF_GROUP; 642 } 643 } 644 645 MCSectionELF *Section = getContext().getELFSection( 646 SectionName, Type, Flags, Size, GroupName, UniqueID, LinkedToSym); 647 getStreamer().SwitchSection(Section, Subsection); 648 // x86-64 psABI names SHT_X86_64_UNWIND as the canonical type for .eh_frame, 649 // but GNU as emits SHT_PROGBITS .eh_frame for .cfi_* directives. Don't error 650 // for SHT_PROGBITS .eh_frame 651 if (Section->getType() != Type && 652 !(SectionName == ".eh_frame" && Type == ELF::SHT_PROGBITS)) 653 Error(loc, "changed section type for " + SectionName + ", expected: 0x" + 654 utohexstr(Section->getType())); 655 // Check that flags are used consistently. However, the GNU assembler permits 656 // to leave out in subsequent uses of the same sections; for compatibility, 657 // do likewise. 658 if ((Flags || Size || !TypeName.empty()) && Section->getFlags() != Flags) 659 Error(loc, "changed section flags for " + SectionName + ", expected: 0x" + 660 utohexstr(Section->getFlags())); 661 if ((Flags || Size || !TypeName.empty()) && Section->getEntrySize() != Size) 662 Error(loc, "changed section entsize for " + SectionName + 663 ", expected: " + Twine(Section->getEntrySize())); 664 665 if (getContext().getGenDwarfForAssembly() && 666 (Section->getFlags() & ELF::SHF_ALLOC) && 667 (Section->getFlags() & ELF::SHF_EXECINSTR)) { 668 bool InsertResult = getContext().addGenDwarfSection(Section); 669 if (InsertResult) { 670 if (getContext().getDwarfVersion() <= 2) 671 Warning(loc, "DWARF2 only supports one section per compilation unit"); 672 673 if (!Section->getBeginSymbol()) { 674 MCSymbol *SectionStartSymbol = getContext().createTempSymbol(); 675 getStreamer().emitLabel(SectionStartSymbol); 676 Section->setBeginSymbol(SectionStartSymbol); 677 } 678 } 679 } 680 681 return false; 682 } 683 684 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) { 685 MCSectionSubPair PreviousSection = getStreamer().getPreviousSection(); 686 if (PreviousSection.first == nullptr) 687 return TokError(".previous without corresponding .section"); 688 getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second); 689 690 return false; 691 } 692 693 static MCSymbolAttr MCAttrForString(StringRef Type) { 694 return StringSwitch<MCSymbolAttr>(Type) 695 .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction) 696 .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject) 697 .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS) 698 .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon) 699 .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType) 700 .Cases("STT_GNU_IFUNC", "gnu_indirect_function", 701 MCSA_ELF_TypeIndFunction) 702 .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject) 703 .Default(MCSA_Invalid); 704 } 705 706 /// ParseDirectiveELFType 707 /// ::= .type identifier , STT_<TYPE_IN_UPPER_CASE> 708 /// ::= .type identifier , #attribute 709 /// ::= .type identifier , @attribute 710 /// ::= .type identifier , %attribute 711 /// ::= .type identifier , "attribute" 712 bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) { 713 StringRef Name; 714 if (getParser().parseIdentifier(Name)) 715 return TokError("expected identifier in directive"); 716 717 // Handle the identifier as the key symbol. 718 MCSymbol *Sym = getContext().getOrCreateSymbol(Name); 719 720 // NOTE the comma is optional in all cases. It is only documented as being 721 // optional in the first case, however, GAS will silently treat the comma as 722 // optional in all cases. Furthermore, although the documentation states that 723 // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS 724 // accepts both the upper case name as well as the lower case aliases. 725 if (getLexer().is(AsmToken::Comma)) 726 Lex(); 727 728 if (getLexer().isNot(AsmToken::Identifier) && 729 getLexer().isNot(AsmToken::Hash) && 730 getLexer().isNot(AsmToken::Percent) && 731 getLexer().isNot(AsmToken::String)) { 732 if (!getLexer().getAllowAtInIdentifier()) 733 return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', " 734 "'%<type>' or \"<type>\""); 735 else if (getLexer().isNot(AsmToken::At)) 736 return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', " 737 "'%<type>' or \"<type>\""); 738 } 739 740 if (getLexer().isNot(AsmToken::String) && 741 getLexer().isNot(AsmToken::Identifier)) 742 Lex(); 743 744 SMLoc TypeLoc = getLexer().getLoc(); 745 746 StringRef Type; 747 if (getParser().parseIdentifier(Type)) 748 return TokError("expected symbol type in directive"); 749 750 MCSymbolAttr Attr = MCAttrForString(Type); 751 if (Attr == MCSA_Invalid) 752 return Error(TypeLoc, "unsupported attribute in '.type' directive"); 753 754 if (getLexer().isNot(AsmToken::EndOfStatement)) 755 return TokError("unexpected token in '.type' directive"); 756 Lex(); 757 758 getStreamer().emitSymbolAttribute(Sym, Attr); 759 760 return false; 761 } 762 763 /// ParseDirectiveIdent 764 /// ::= .ident string 765 bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) { 766 if (getLexer().isNot(AsmToken::String)) 767 return TokError("unexpected token in '.ident' directive"); 768 769 StringRef Data = getTok().getIdentifier(); 770 771 Lex(); 772 773 if (getLexer().isNot(AsmToken::EndOfStatement)) 774 return TokError("unexpected token in '.ident' directive"); 775 Lex(); 776 777 getStreamer().emitIdent(Data); 778 return false; 779 } 780 781 /// ParseDirectiveSymver 782 /// ::= .symver foo, bar2@zed 783 bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) { 784 StringRef Name; 785 if (getParser().parseIdentifier(Name)) 786 return TokError("expected identifier in directive"); 787 788 if (getLexer().isNot(AsmToken::Comma)) 789 return TokError("expected a comma"); 790 791 // ARM assembly uses @ for a comment... 792 // except when parsing the second parameter of the .symver directive. 793 // Force the next symbol to allow @ in the identifier, which is 794 // required for this directive and then reset it to its initial state. 795 const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier(); 796 getLexer().setAllowAtInIdentifier(true); 797 Lex(); 798 getLexer().setAllowAtInIdentifier(AllowAtInIdentifier); 799 800 StringRef AliasName; 801 if (getParser().parseIdentifier(AliasName)) 802 return TokError("expected identifier in directive"); 803 804 if (AliasName.find('@') == StringRef::npos) 805 return TokError("expected a '@' in the name"); 806 807 MCSymbol *Sym = getContext().getOrCreateSymbol(Name); 808 getStreamer().emitELFSymverDirective(AliasName, Sym); 809 return false; 810 } 811 812 /// ParseDirectiveVersion 813 /// ::= .version string 814 bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) { 815 if (getLexer().isNot(AsmToken::String)) 816 return TokError("unexpected token in '.version' directive"); 817 818 StringRef Data = getTok().getIdentifier(); 819 820 Lex(); 821 822 MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0); 823 824 getStreamer().PushSection(); 825 getStreamer().SwitchSection(Note); 826 getStreamer().emitInt32(Data.size() + 1); // namesz 827 getStreamer().emitInt32(0); // descsz = 0 (no description). 828 getStreamer().emitInt32(1); // type = NT_VERSION 829 getStreamer().emitBytes(Data); // name 830 getStreamer().emitInt8(0); // NUL 831 getStreamer().emitValueToAlignment(4); 832 getStreamer().PopSection(); 833 return false; 834 } 835 836 /// ParseDirectiveWeakref 837 /// ::= .weakref foo, bar 838 bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) { 839 // FIXME: Share code with the other alias building directives. 840 841 StringRef AliasName; 842 if (getParser().parseIdentifier(AliasName)) 843 return TokError("expected identifier in directive"); 844 845 if (getLexer().isNot(AsmToken::Comma)) 846 return TokError("expected a comma"); 847 848 Lex(); 849 850 StringRef Name; 851 if (getParser().parseIdentifier(Name)) 852 return TokError("expected identifier in directive"); 853 854 MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName); 855 856 MCSymbol *Sym = getContext().getOrCreateSymbol(Name); 857 858 getStreamer().emitWeakReference(Alias, Sym); 859 return false; 860 } 861 862 bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) { 863 const MCExpr *Subsection = nullptr; 864 if (getLexer().isNot(AsmToken::EndOfStatement)) { 865 if (getParser().parseExpression(Subsection)) 866 return true; 867 } 868 869 if (getLexer().isNot(AsmToken::EndOfStatement)) 870 return TokError("unexpected token in directive"); 871 872 Lex(); 873 874 getStreamer().SubSection(Subsection); 875 return false; 876 } 877 878 bool ELFAsmParser::ParseDirectiveCGProfile(StringRef S, SMLoc Loc) { 879 return MCAsmParserExtension::ParseDirectiveCGProfile(S, Loc); 880 } 881 882 namespace llvm { 883 884 MCAsmParserExtension *createELFAsmParser() { 885 return new ELFAsmParser; 886 } 887 888 } // end namespace llvm 889