llvm/lib/MC/MCParser/ELFAsmParser.cpp

   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/StringExtras.h"
  10 #include "llvm/ADT/StringRef.h"
  11 #include "llvm/ADT/StringSwitch.h"
  12 #include "llvm/BinaryFormat/ELF.h"
  13 #include "llvm/MC/MCAsmInfo.h"
  14 #include "llvm/MC/MCContext.h"
  15 #include "llvm/MC/MCDirectives.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/MCSectionELF.h"
  20 #include "llvm/MC/MCStreamer.h"
  21 #include "llvm/MC/MCSymbol.h"
  22 #include "llvm/MC/MCSymbolELF.h"
  23 #include "llvm/MC/SectionKind.h"
  24 #include "llvm/Support/Casting.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/SMLoc.h"
  27 #include <cassert>
  28 #include <cstdint>
  29 #include <utility>
  30
  31 using namespace llvm;
  32
  33 namespace {
  34
  35 class ELFAsmParser : public MCAsmParserExtension {
  36   template<bool (ELFAsmParser::*HandlerMethod)(StringRef, SMLoc)>
  37   void addDirectiveHandler(StringRef Directive) {
  38     MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair(
  39         this, HandleDirective<ELFAsmParser, HandlerMethod>);
  40
  41     getParser().addDirectiveHandler(Directive, Handler);
  42   }
  43
  44   bool ParseSectionSwitch(StringRef Section, unsigned Type, unsigned Flags,
  45                           SectionKind Kind);
  46
  47 public:
  48   ELFAsmParser() { BracketExpressionsSupported = true; }
  49
  50   void Initialize(MCAsmParser &Parser) override {
  51     // Call the base implementation.
  52     this->MCAsmParserExtension::Initialize(Parser);
  53
  54     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
  55     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
  56     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
  57     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
  58     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
  59     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
  60     addDirectiveHandler<
  61       &ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel");
  62     addDirectiveHandler<
  63       &ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro");
  64     addDirectiveHandler<
  65       &ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
  66     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
  67     addDirectiveHandler<
  68       &ELFAsmParser::ParseDirectivePushSection>(".pushsection");
  69     addDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
  70     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
  71     addDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
  72     addDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
  73     addDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
  74     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
  75     addDirectiveHandler<&ELFAsmParser::ParseDirectiveVersion>(".version");
  76     addDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
  77     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
  78     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local");
  79     addDirectiveHandler<
  80       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".protected");
  81     addDirectiveHandler<
  82       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".internal");
  83     addDirectiveHandler<
  84       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".hidden");
  85     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSubsection>(".subsection");
  86     addDirectiveHandler<&ELFAsmParser::ParseDirectiveCGProfile>(".cg_profile");
  87   }
  88
  89   // FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
  90   // the best way for us to get access to it?
  91   bool ParseSectionDirectiveData(StringRef, SMLoc) {
  92     return ParseSectionSwitch(".data", ELF::SHT_PROGBITS,
  93                               ELF::SHF_WRITE | ELF::SHF_ALLOC,
  94                               SectionKind::getData());
  95   }
  96   bool ParseSectionDirectiveText(StringRef, SMLoc) {
  97     return ParseSectionSwitch(".text", ELF::SHT_PROGBITS,
  98                               ELF::SHF_EXECINSTR |
  99                               ELF::SHF_ALLOC, SectionKind::getText());
 100   }
 101   bool ParseSectionDirectiveBSS(StringRef, SMLoc) {
 102     return ParseSectionSwitch(".bss", ELF::SHT_NOBITS,
 103                               ELF::SHF_WRITE |
 104                               ELF::SHF_ALLOC, SectionKind::getBSS());
 105   }
 106   bool ParseSectionDirectiveRoData(StringRef, SMLoc) {
 107     return ParseSectionSwitch(".rodata", ELF::SHT_PROGBITS,
 108                               ELF::SHF_ALLOC,
 109                               SectionKind::getReadOnly());
 110   }
 111   bool ParseSectionDirectiveTData(StringRef, SMLoc) {
 112     return ParseSectionSwitch(".tdata", ELF::SHT_PROGBITS,
 113                               ELF::SHF_ALLOC |
 114                               ELF::SHF_TLS | ELF::SHF_WRITE,
 115                               SectionKind::getThreadData());
 116   }
 117   bool ParseSectionDirectiveTBSS(StringRef, SMLoc) {
 118     return ParseSectionSwitch(".tbss", ELF::SHT_NOBITS,
 119                               ELF::SHF_ALLOC |
 120                               ELF::SHF_TLS | ELF::SHF_WRITE,
 121                               SectionKind::getThreadBSS());
 122   }
 123   bool ParseSectionDirectiveDataRel(StringRef, SMLoc) {
 124     return ParseSectionSwitch(".data.rel", ELF::SHT_PROGBITS,
 125                               ELF::SHF_ALLOC | ELF::SHF_WRITE,
 126                               SectionKind::getData());
 127   }
 128   bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) {
 129     return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS,
 130                               ELF::SHF_ALLOC |
 131                               ELF::SHF_WRITE,
 132                               SectionKind::getReadOnlyWithRel());
 133   }
 134   bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) {
 135     return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS,
 136                               ELF::SHF_ALLOC | ELF::SHF_WRITE,
 137                               SectionKind::getData());
 138   }
 139   bool ParseDirectivePushSection(StringRef, SMLoc);
 140   bool ParseDirectivePopSection(StringRef, SMLoc);
 141   bool ParseDirectiveSection(StringRef, SMLoc);
 142   bool ParseDirectiveSize(StringRef, SMLoc);
 143   bool ParseDirectivePrevious(StringRef, SMLoc);
 144   bool ParseDirectiveType(StringRef, SMLoc);
 145   bool ParseDirectiveIdent(StringRef, SMLoc);
 146   bool ParseDirectiveSymver(StringRef, SMLoc);
 147   bool ParseDirectiveVersion(StringRef, SMLoc);
 148   bool ParseDirectiveWeakref(StringRef, SMLoc);
 149   bool ParseDirectiveSymbolAttribute(StringRef, SMLoc);
 150   bool ParseDirectiveSubsection(StringRef, SMLoc);
 151   bool ParseDirectiveCGProfile(StringRef, SMLoc);
 152
 153 private:
 154   bool ParseSectionName(StringRef &SectionName);
 155   bool ParseSectionArguments(bool IsPush, SMLoc loc);
 156   unsigned parseSunStyleSectionFlags();
 157   bool maybeParseSectionType(StringRef &TypeName);
 158   bool parseMergeSize(int64_t &Size);
 159   bool parseGroup(StringRef &GroupName, bool &IsComdat);
 160   bool parseLinkedToSym(MCSymbolELF *&LinkedToSym);
 161   bool maybeParseUniqueID(int64_t &UniqueID);
 162 };
 163
 164 } // end anonymous namespace
 165
 166 /// ParseDirectiveSymbolAttribute
 167 ///  ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ]
 168 bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
 169   MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
 170     .Case(".weak", MCSA_Weak)
 171     .Case(".local", MCSA_Local)
 172     .Case(".hidden", MCSA_Hidden)
 173     .Case(".internal", MCSA_Internal)
 174     .Case(".protected", MCSA_Protected)
 175     .Default(MCSA_Invalid);
 176   assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
 177   if (getLexer().isNot(AsmToken::EndOfStatement)) {
 178     while (true) {
 179       StringRef Name;
 180
 181       if (getParser().parseIdentifier(Name))
 182         return TokError("expected identifier");
 183
 184       if (getParser().discardLTOSymbol(Name)) {
 185         if (getLexer().is(AsmToken::EndOfStatement))
 186           break;
 187         continue;
 188       }
 189
 190       MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 191
 192       getStreamer().emitSymbolAttribute(Sym, Attr);
 193
 194       if (getLexer().is(AsmToken::EndOfStatement))
 195         break;
 196
 197       if (getLexer().isNot(AsmToken::Comma))
 198         return TokError("expected comma");
 199       Lex();
 200     }
 201   }
 202
 203   Lex();
 204   return false;
 205 }
 206
 207 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
 208                                       unsigned Flags, SectionKind Kind) {
 209   const MCExpr *Subsection = nullptr;
 210   if (getLexer().isNot(AsmToken::EndOfStatement)) {
 211     if (getParser().parseExpression(Subsection))
 212       return true;
 213   }
 214   Lex();
 215
 216   getStreamer().switchSection(getContext().getELFSection(Section, Type, Flags),
 217                               Subsection);
 218
 219   return false;
 220 }
 221
 222 bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
 223   StringRef Name;
 224   if (getParser().parseIdentifier(Name))
 225     return TokError("expected identifier");
 226   MCSymbolELF *Sym = cast<MCSymbolELF>(getContext().getOrCreateSymbol(Name));
 227
 228   if (getLexer().isNot(AsmToken::Comma))
 229     return TokError("expected comma");
 230   Lex();
 231
 232   const MCExpr *Expr;
 233   if (getParser().parseExpression(Expr))
 234     return true;
 235
 236   if (getLexer().isNot(AsmToken::EndOfStatement))
 237     return TokError("unexpected token");
 238   Lex();
 239
 240   getStreamer().emitELFSize(Sym, Expr);
 241   return false;
 242 }
 243
 244 bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
 245   // A section name can contain -, so we cannot just use
 246   // parseIdentifier.
 247   SMLoc FirstLoc = getLexer().getLoc();
 248   unsigned Size = 0;
 249
 250   if (getLexer().is(AsmToken::String)) {
 251     SectionName = getTok().getIdentifier();
 252     Lex();
 253     return false;
 254   }
 255
 256   while (!getParser().hasPendingError()) {
 257     SMLoc PrevLoc = getLexer().getLoc();
 258     if (getLexer().is(AsmToken::Comma) ||
 259       getLexer().is(AsmToken::EndOfStatement))
 260       break;
 261
 262     unsigned CurSize;
 263     if (getLexer().is(AsmToken::String)) {
 264       CurSize = getTok().getIdentifier().size() + 2;
 265       Lex();
 266     } else if (getLexer().is(AsmToken::Identifier)) {
 267       CurSize = getTok().getIdentifier().size();
 268       Lex();
 269     } else {
 270       CurSize = getTok().getString().size();
 271       Lex();
 272     }
 273     Size += CurSize;
 274     SectionName = StringRef(FirstLoc.getPointer(), Size);
 275
 276     // Make sure the following token is adjacent.
 277     if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
 278       break;
 279   }
 280   if (Size == 0)
 281     return true;
 282
 283   return false;
 284 }
 285
 286 static unsigned parseSectionFlags(const Triple &TT, StringRef flagsStr,
 287                                   bool *UseLastGroup) {
 288   unsigned flags = 0;
 289
 290   // If a valid numerical value is set for the section flag, use it verbatim
 291   if (!flagsStr.getAsInteger(0, flags))
 292     return flags;
 293
 294   for (char i : flagsStr) {
 295     switch (i) {
 296     case 'a':
 297       flags |= ELF::SHF_ALLOC;
 298       break;
 299     case 'e':
 300       flags |= ELF::SHF_EXCLUDE;
 301       break;
 302     case 'x':
 303       flags |= ELF::SHF_EXECINSTR;
 304       break;
 305     case 'w':
 306       flags |= ELF::SHF_WRITE;
 307       break;
 308     case 'o':
 309       flags |= ELF::SHF_LINK_ORDER;
 310       break;
 311     case 'M':
 312       flags |= ELF::SHF_MERGE;
 313       break;
 314     case 'S':
 315       flags |= ELF::SHF_STRINGS;
 316       break;
 317     case 'T':
 318       flags |= ELF::SHF_TLS;
 319       break;
 320     case 'c':
 321       if (TT.getArch() != Triple::xcore)
 322         return -1U;
 323       flags |= ELF::XCORE_SHF_CP_SECTION;
 324       break;
 325     case 'd':
 326       if (TT.getArch() != Triple::xcore)
 327         return -1U;
 328       flags |= ELF::XCORE_SHF_DP_SECTION;
 329       break;
 330     case 'y':
 331       if (!(TT.isARM() || TT.isThumb()))
 332         return -1U;
 333       flags |= ELF::SHF_ARM_PURECODE;
 334       break;
 335     case 's':
 336       if (TT.getArch() != Triple::hexagon)
 337         return -1U;
 338       flags |= ELF::SHF_HEX_GPREL;
 339       break;
 340     case 'G':
 341       flags |= ELF::SHF_GROUP;
 342       break;
 343     case 'l':
 344       if (TT.getArch() != Triple::x86_64)
 345         return -1U;
 346       flags |= ELF::SHF_X86_64_LARGE;
 347       break;
 348     case 'R':
 349       if (TT.isOSSolaris())
 350         flags |= ELF::SHF_SUNW_NODISCARD;
 351       else
 352         flags |= ELF::SHF_GNU_RETAIN;
 353       break;
 354     case '?':
 355       *UseLastGroup = true;
 356       break;
 357     default:
 358       return -1U;
 359     }
 360   }
 361
 362   return flags;
 363 }
 364
 365 unsigned ELFAsmParser::parseSunStyleSectionFlags() {
 366   unsigned flags = 0;
 367   while (getLexer().is(AsmToken::Hash)) {
 368     Lex(); // Eat the #.
 369
 370     if (!getLexer().is(AsmToken::Identifier))
 371       return -1U;
 372
 373     StringRef flagId = getTok().getIdentifier();
 374     if (flagId == "alloc")
 375       flags |= ELF::SHF_ALLOC;
 376     else if (flagId == "execinstr")
 377       flags |= ELF::SHF_EXECINSTR;
 378     else if (flagId == "write")
 379       flags |= ELF::SHF_WRITE;
 380     else if (flagId == "tls")
 381       flags |= ELF::SHF_TLS;
 382     else
 383       return -1U;
 384
 385     Lex(); // Eat the flag.
 386
 387     if (!getLexer().is(AsmToken::Comma))
 388         break;
 389     Lex(); // Eat the comma.
 390   }
 391   return flags;
 392 }
 393
 394
 395 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
 396   getStreamer().pushSection();
 397
 398   if (ParseSectionArguments(/*IsPush=*/true, loc)) {
 399     getStreamer().popSection();
 400     return true;
 401   }
 402
 403   return false;
 404 }
 405
 406 bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
 407   if (!getStreamer().popSection())
 408     return TokError(".popsection without corresponding .pushsection");
 409   return false;
 410 }
 411
 412 bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
 413   return ParseSectionArguments(/*IsPush=*/false, loc);
 414 }
 415
 416 bool ELFAsmParser::maybeParseSectionType(StringRef &TypeName) {
 417   MCAsmLexer &L = getLexer();
 418   if (L.isNot(AsmToken::Comma))
 419     return false;
 420   Lex();
 421   if (L.isNot(AsmToken::At) && L.isNot(AsmToken::Percent) &&
 422       L.isNot(AsmToken::String)) {
 423     if (L.getAllowAtInIdentifier())
 424       return TokError("expected '@<type>', '%<type>' or \"<type>\"");
 425     else
 426       return TokError("expected '%<type>' or \"<type>\"");
 427   }
 428   if (!L.is(AsmToken::String))
 429     Lex();
 430   if (L.is(AsmToken::Integer)) {
 431     TypeName = getTok().getString();
 432     Lex();
 433   } else if (getParser().parseIdentifier(TypeName))
 434     return TokError("expected identifier");
 435   return false;
 436 }
 437
 438 bool ELFAsmParser::parseMergeSize(int64_t &Size) {
 439   if (getLexer().isNot(AsmToken::Comma))
 440     return TokError("expected the entry size");
 441   Lex();
 442   if (getParser().parseAbsoluteExpression(Size))
 443     return true;
 444   if (Size <= 0)
 445     return TokError("entry size must be positive");
 446   return false;
 447 }
 448
 449 bool ELFAsmParser::parseGroup(StringRef &GroupName, bool &IsComdat) {
 450   MCAsmLexer &L = getLexer();
 451   if (L.isNot(AsmToken::Comma))
 452     return TokError("expected group name");
 453   Lex();
 454   if (L.is(AsmToken::Integer)) {
 455     GroupName = getTok().getString();
 456     Lex();
 457   } else if (getParser().parseIdentifier(GroupName)) {
 458     return TokError("invalid group name");
 459   }
 460   if (L.is(AsmToken::Comma)) {
 461     Lex();
 462     StringRef Linkage;
 463     if (getParser().parseIdentifier(Linkage))
 464       return TokError("invalid linkage");
 465     if (Linkage != "comdat")
 466       return TokError("Linkage must be 'comdat'");
 467     IsComdat = true;
 468   } else {
 469     IsComdat = false;
 470   }
 471   return false;
 472 }
 473
 474 bool ELFAsmParser::parseLinkedToSym(MCSymbolELF *&LinkedToSym) {
 475   MCAsmLexer &L = getLexer();
 476   if (L.isNot(AsmToken::Comma))
 477     return TokError("expected linked-to symbol");
 478   Lex();
 479   StringRef Name;
 480   SMLoc StartLoc = L.getLoc();
 481   if (getParser().parseIdentifier(Name)) {
 482     if (getParser().getTok().getString() == "0") {
 483       getParser().Lex();
 484       LinkedToSym = nullptr;
 485       return false;
 486     }
 487     return TokError("invalid linked-to symbol");
 488   }
 489   LinkedToSym = dyn_cast_or_null<MCSymbolELF>(getContext().lookupSymbol(Name));
 490   if (!LinkedToSym || !LinkedToSym->isInSection())
 491     return Error(StartLoc, "linked-to symbol is not in a section: " + Name);
 492   return false;
 493 }
 494
 495 bool ELFAsmParser::maybeParseUniqueID(int64_t &UniqueID) {
 496   MCAsmLexer &L = getLexer();
 497   if (L.isNot(AsmToken::Comma))
 498     return false;
 499   Lex();
 500   StringRef UniqueStr;
 501   if (getParser().parseIdentifier(UniqueStr))
 502     return TokError("expected identifier");
 503   if (UniqueStr != "unique")
 504     return TokError("expected 'unique'");
 505   if (L.isNot(AsmToken::Comma))
 506     return TokError("expected commma");
 507   Lex();
 508   if (getParser().parseAbsoluteExpression(UniqueID))
 509     return true;
 510   if (UniqueID < 0)
 511     return TokError("unique id must be positive");
 512   if (!isUInt<32>(UniqueID) || UniqueID == ~0U)
 513     return TokError("unique id is too large");
 514   return false;
 515 }
 516
 517 static bool hasPrefix(StringRef SectionName, StringRef Prefix) {
 518   return SectionName.consume_front(Prefix) &&
 519          (SectionName.empty() || SectionName[0] == '.');
 520 }
 521
 522 static bool allowSectionTypeMismatch(const Triple &TT, StringRef SectionName,
 523                                      unsigned Type) {
 524   if (TT.getArch() == Triple::x86_64) {
 525     // x86-64 psABI names SHT_X86_64_UNWIND as the canonical type for .eh_frame,
 526     // but GNU as emits SHT_PROGBITS .eh_frame for .cfi_* directives. Don't
 527     // error for SHT_PROGBITS .eh_frame
 528     return SectionName == ".eh_frame" && Type == ELF::SHT_PROGBITS;
 529   }
 530   if (TT.isMIPS()) {
 531     // MIPS .debug_* sections should have SHT_MIPS_DWARF section type to
 532     // distinguish among sections contain DWARF and ECOFF debug formats,
 533     // but in assembly files these sections have SHT_PROGBITS type.
 534     return SectionName.starts_with(".debug_") && Type == ELF::SHT_PROGBITS;
 535   }
 536   return false;
 537 }
 538
 539 bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
 540   StringRef SectionName;
 541
 542   if (ParseSectionName(SectionName))
 543     return TokError("expected identifier");
 544
 545   StringRef TypeName;
 546   int64_t Size = 0;
 547   StringRef GroupName;
 548   bool IsComdat = false;
 549   unsigned Flags = 0;
 550   unsigned extraFlags = 0;
 551   const MCExpr *Subsection = nullptr;
 552   bool UseLastGroup = false;
 553   MCSymbolELF *LinkedToSym = nullptr;
 554   int64_t UniqueID = ~0;
 555
 556   // Set the defaults first.
 557   if (hasPrefix(SectionName, ".rodata") || SectionName == ".rodata1")
 558     Flags |= ELF::SHF_ALLOC;
 559   else if (SectionName == ".fini" || SectionName == ".init" ||
 560            hasPrefix(SectionName, ".text"))
 561     Flags |= ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
 562   else if (hasPrefix(SectionName, ".data") || SectionName == ".data1" ||
 563            hasPrefix(SectionName, ".bss") ||
 564            hasPrefix(SectionName, ".init_array") ||
 565            hasPrefix(SectionName, ".fini_array") ||
 566            hasPrefix(SectionName, ".preinit_array"))
 567     Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE;
 568   else if (hasPrefix(SectionName, ".tdata") || hasPrefix(SectionName, ".tbss"))
 569     Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_TLS;
 570
 571   if (getLexer().is(AsmToken::Comma)) {
 572     Lex();
 573
 574     if (IsPush && getLexer().isNot(AsmToken::String)) {
 575       if (getParser().parseExpression(Subsection))
 576         return true;
 577       if (getLexer().isNot(AsmToken::Comma))
 578         goto EndStmt;
 579       Lex();
 580     }
 581
 582     if (getLexer().isNot(AsmToken::String)) {
 583       if (getLexer().isNot(AsmToken::Hash))
 584         return TokError("expected string");
 585       extraFlags = parseSunStyleSectionFlags();
 586     } else {
 587       StringRef FlagsStr = getTok().getStringContents();
 588       Lex();
 589       extraFlags = parseSectionFlags(getContext().getTargetTriple(), FlagsStr,
 590                                      &UseLastGroup);
 591     }
 592
 593     if (extraFlags == -1U)
 594       return TokError("unknown flag");
 595     Flags |= extraFlags;
 596
 597     bool Mergeable = Flags & ELF::SHF_MERGE;
 598     bool Group = Flags & ELF::SHF_GROUP;
 599     if (Group && UseLastGroup)
 600       return TokError("Section cannot specifiy a group name while also acting "
 601                       "as a member of the last group");
 602
 603     if (maybeParseSectionType(TypeName))
 604       return true;
 605
 606     MCAsmLexer &L = getLexer();
 607     if (TypeName.empty()) {
 608       if (Mergeable)
 609         return TokError("Mergeable section must specify the type");
 610       if (Group)
 611         return TokError("Group section must specify the type");
 612       if (L.isNot(AsmToken::EndOfStatement))
 613         return TokError("expected end of directive");
 614     }
 615
 616     if (Mergeable)
 617       if (parseMergeSize(Size))
 618         return true;
 619     if (Flags & ELF::SHF_LINK_ORDER)
 620       if (parseLinkedToSym(LinkedToSym))
 621         return true;
 622     if (Group)
 623       if (parseGroup(GroupName, IsComdat))
 624         return true;
 625     if (maybeParseUniqueID(UniqueID))
 626       return true;
 627   }
 628
 629 EndStmt:
 630   if (getLexer().isNot(AsmToken::EndOfStatement))
 631     return TokError("expected end of directive");
 632   Lex();
 633
 634   unsigned Type = ELF::SHT_PROGBITS;
 635
 636   if (TypeName.empty()) {
 637     if (SectionName.starts_with(".note"))
 638       Type = ELF::SHT_NOTE;
 639     else if (hasPrefix(SectionName, ".init_array"))
 640       Type = ELF::SHT_INIT_ARRAY;
 641     else if (hasPrefix(SectionName, ".bss"))
 642       Type = ELF::SHT_NOBITS;
 643     else if (hasPrefix(SectionName, ".tbss"))
 644       Type = ELF::SHT_NOBITS;
 645     else if (hasPrefix(SectionName, ".fini_array"))
 646       Type = ELF::SHT_FINI_ARRAY;
 647     else if (hasPrefix(SectionName, ".preinit_array"))
 648       Type = ELF::SHT_PREINIT_ARRAY;
 649   } else {
 650     if (TypeName == "init_array")
 651       Type = ELF::SHT_INIT_ARRAY;
 652     else if (TypeName == "fini_array")
 653       Type = ELF::SHT_FINI_ARRAY;
 654     else if (TypeName == "preinit_array")
 655       Type = ELF::SHT_PREINIT_ARRAY;
 656     else if (TypeName == "nobits")
 657       Type = ELF::SHT_NOBITS;
 658     else if (TypeName == "progbits")
 659       Type = ELF::SHT_PROGBITS;
 660     else if (TypeName == "note")
 661       Type = ELF::SHT_NOTE;
 662     else if (TypeName == "unwind")
 663       Type = ELF::SHT_X86_64_UNWIND;
 664     else if (TypeName == "llvm_odrtab")
 665       Type = ELF::SHT_LLVM_ODRTAB;
 666     else if (TypeName == "llvm_linker_options")
 667       Type = ELF::SHT_LLVM_LINKER_OPTIONS;
 668     else if (TypeName == "llvm_call_graph_profile")
 669       Type = ELF::SHT_LLVM_CALL_GRAPH_PROFILE;
 670     else if (TypeName == "llvm_dependent_libraries")
 671       Type = ELF::SHT_LLVM_DEPENDENT_LIBRARIES;
 672     else if (TypeName == "llvm_sympart")
 673       Type = ELF::SHT_LLVM_SYMPART;
 674     else if (TypeName == "llvm_bb_addr_map")
 675       Type = ELF::SHT_LLVM_BB_ADDR_MAP;
 676     else if (TypeName == "llvm_offloading")
 677       Type = ELF::SHT_LLVM_OFFLOADING;
 678     else if (TypeName == "llvm_lto")
 679       Type = ELF::SHT_LLVM_LTO;
 680     else if (TypeName.getAsInteger(0, Type))
 681       return TokError("unknown section type");
 682   }
 683
 684   if (UseLastGroup) {
 685     MCSectionSubPair CurrentSection = getStreamer().getCurrentSection();
 686     if (const MCSectionELF *Section =
 687             cast_or_null<MCSectionELF>(CurrentSection.first))
 688       if (const MCSymbol *Group = Section->getGroup()) {
 689         GroupName = Group->getName();
 690         IsComdat = Section->isComdat();
 691         Flags |= ELF::SHF_GROUP;
 692       }
 693   }
 694
 695   MCSectionELF *Section =
 696       getContext().getELFSection(SectionName, Type, Flags, Size, GroupName,
 697                                  IsComdat, UniqueID, LinkedToSym);
 698   getStreamer().switchSection(Section, Subsection);
 699   // Check that flags are used consistently. However, the GNU assembler permits
 700   // to leave out in subsequent uses of the same sections; for compatibility,
 701   // do likewise.
 702   if (!TypeName.empty() && Section->getType() != Type &&
 703       !allowSectionTypeMismatch(getContext().getTargetTriple(), SectionName,
 704                                 Type))
 705     Error(loc, "changed section type for " + SectionName + ", expected: 0x" +
 706                    utohexstr(Section->getType()));
 707   if ((extraFlags || Size || !TypeName.empty()) && Section->getFlags() != Flags)
 708     Error(loc, "changed section flags for " + SectionName + ", expected: 0x" +
 709                    utohexstr(Section->getFlags()));
 710   if ((extraFlags || Size || !TypeName.empty()) &&
 711       Section->getEntrySize() != Size)
 712     Error(loc, "changed section entsize for " + SectionName +
 713                    ", expected: " + Twine(Section->getEntrySize()));
 714
 715   if (getContext().getGenDwarfForAssembly() &&
 716       (Section->getFlags() & ELF::SHF_ALLOC) &&
 717       (Section->getFlags() & ELF::SHF_EXECINSTR)) {
 718     bool InsertResult = getContext().addGenDwarfSection(Section);
 719     if (InsertResult) {
 720       if (getContext().getDwarfVersion() <= 2)
 721         Warning(loc, "DWARF2 only supports one section per compilation unit");
 722
 723       if (!Section->getBeginSymbol()) {
 724         MCSymbol *SectionStartSymbol = getContext().createTempSymbol();
 725         getStreamer().emitLabel(SectionStartSymbol);
 726         Section->setBeginSymbol(SectionStartSymbol);
 727       }
 728     }
 729   }
 730
 731   return false;
 732 }
 733
 734 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
 735   MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
 736   if (PreviousSection.first == nullptr)
 737       return TokError(".previous without corresponding .section");
 738   getStreamer().switchSection(PreviousSection.first, PreviousSection.second);
 739
 740   return false;
 741 }
 742
 743 static MCSymbolAttr MCAttrForString(StringRef Type) {
 744   return StringSwitch<MCSymbolAttr>(Type)
 745           .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
 746           .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
 747           .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
 748           .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
 749           .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
 750           .Cases("STT_GNU_IFUNC", "gnu_indirect_function",
 751                  MCSA_ELF_TypeIndFunction)
 752           .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
 753           .Default(MCSA_Invalid);
 754 }
 755
 756 /// ParseDirectiveELFType
 757 ///  ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
 758 ///  ::= .type identifier , #attribute
 759 ///  ::= .type identifier , @attribute
 760 ///  ::= .type identifier , %attribute
 761 ///  ::= .type identifier , "attribute"
 762 bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
 763   StringRef Name;
 764   if (getParser().parseIdentifier(Name))
 765     return TokError("expected identifier");
 766
 767   // Handle the identifier as the key symbol.
 768   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 769
 770   // NOTE the comma is optional in all cases.  It is only documented as being
 771   // optional in the first case, however, GAS will silently treat the comma as
 772   // optional in all cases.  Furthermore, although the documentation states that
 773   // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
 774   // accepts both the upper case name as well as the lower case aliases.
 775   if (getLexer().is(AsmToken::Comma))
 776     Lex();
 777
 778   if (getLexer().isNot(AsmToken::Identifier) &&
 779       getLexer().isNot(AsmToken::Hash) &&
 780       getLexer().isNot(AsmToken::Percent) &&
 781       getLexer().isNot(AsmToken::String)) {
 782     if (!getLexer().getAllowAtInIdentifier())
 783       return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', "
 784                       "'%<type>' or \"<type>\"");
 785     else if (getLexer().isNot(AsmToken::At))
 786       return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
 787                       "'%<type>' or \"<type>\"");
 788   }
 789
 790   if (getLexer().isNot(AsmToken::String) &&
 791       getLexer().isNot(AsmToken::Identifier))
 792     Lex();
 793
 794   SMLoc TypeLoc = getLexer().getLoc();
 795
 796   StringRef Type;
 797   if (getParser().parseIdentifier(Type))
 798     return TokError("expected symbol type");
 799
 800   MCSymbolAttr Attr = MCAttrForString(Type);
 801   if (Attr == MCSA_Invalid)
 802     return Error(TypeLoc, "unsupported attribute");
 803
 804   if (getLexer().isNot(AsmToken::EndOfStatement))
 805     return TokError("expected end of directive");
 806   Lex();
 807
 808   getStreamer().emitSymbolAttribute(Sym, Attr);
 809
 810   return false;
 811 }
 812
 813 /// ParseDirectiveIdent
 814 ///  ::= .ident string
 815 bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
 816   if (getLexer().isNot(AsmToken::String))
 817     return TokError("expected string");
 818
 819   StringRef Data = getTok().getIdentifier();
 820
 821   Lex();
 822
 823   if (getLexer().isNot(AsmToken::EndOfStatement))
 824     return TokError("expected end of directive");
 825   Lex();
 826
 827   getStreamer().emitIdent(Data);
 828   return false;
 829 }
 830
 831 /// ParseDirectiveSymver
 832 ///  ::= .symver foo, bar2@zed
 833 bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
 834   StringRef OriginalName, Name, Action;
 835   if (getParser().parseIdentifier(OriginalName))
 836     return TokError("expected identifier");
 837
 838   if (getLexer().isNot(AsmToken::Comma))
 839     return TokError("expected a comma");
 840
 841   // ARM assembly uses @ for a comment...
 842   // except when parsing the second parameter of the .symver directive.
 843   // Force the next symbol to allow @ in the identifier, which is
 844   // required for this directive and then reset it to its initial state.
 845   const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
 846   getLexer().setAllowAtInIdentifier(true);
 847   Lex();
 848   getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
 849
 850   if (getParser().parseIdentifier(Name))
 851     return TokError("expected identifier");
 852
 853   if (!Name.contains('@'))
 854     return TokError("expected a '@' in the name");
 855   bool KeepOriginalSym = !Name.contains("@@@");
 856   if (parseOptionalToken(AsmToken::Comma)) {
 857     if (getParser().parseIdentifier(Action) || Action != "remove")
 858       return TokError("expected 'remove'");
 859     KeepOriginalSym = false;
 860   }
 861   (void)parseOptionalToken(AsmToken::EndOfStatement);
 862
 863   getStreamer().emitELFSymverDirective(
 864       getContext().getOrCreateSymbol(OriginalName), Name, KeepOriginalSym);
 865   return false;
 866 }
 867
 868 /// ParseDirectiveVersion
 869 ///  ::= .version string
 870 bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
 871   if (getLexer().isNot(AsmToken::String))
 872     return TokError("expected string");
 873
 874   StringRef Data = getTok().getIdentifier();
 875
 876   Lex();
 877
 878   MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0);
 879
 880   getStreamer().pushSection();
 881   getStreamer().switchSection(Note);
 882   getStreamer().emitInt32(Data.size() + 1); // namesz
 883   getStreamer().emitInt32(0);               // descsz = 0 (no description).
 884   getStreamer().emitInt32(1);               // type = NT_VERSION
 885   getStreamer().emitBytes(Data);            // name
 886   getStreamer().emitInt8(0);                // NUL
 887   getStreamer().emitValueToAlignment(Align(4));
 888   getStreamer().popSection();
 889   return false;
 890 }
 891
 892 /// ParseDirectiveWeakref
 893 ///  ::= .weakref foo, bar
 894 bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
 895   // FIXME: Share code with the other alias building directives.
 896
 897   StringRef AliasName;
 898   if (getParser().parseIdentifier(AliasName))
 899     return TokError("expected identifier");
 900
 901   if (getLexer().isNot(AsmToken::Comma))
 902     return TokError("expected a comma");
 903
 904   Lex();
 905
 906   StringRef Name;
 907   if (getParser().parseIdentifier(Name))
 908     return TokError("expected identifier");
 909
 910   MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
 911
 912   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 913
 914   getStreamer().emitWeakReference(Alias, Sym);
 915   return false;
 916 }
 917
 918 bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) {
 919   const MCExpr *Subsection = nullptr;
 920   if (getLexer().isNot(AsmToken::EndOfStatement)) {
 921     if (getParser().parseExpression(Subsection))
 922      return true;
 923   }
 924
 925   if (getLexer().isNot(AsmToken::EndOfStatement))
 926     return TokError("expected end of directive");
 927
 928   Lex();
 929
 930   getStreamer().subSection(Subsection);
 931   return false;
 932 }
 933
 934 bool ELFAsmParser::ParseDirectiveCGProfile(StringRef S, SMLoc Loc) {
 935   return MCAsmParserExtension::ParseDirectiveCGProfile(S, Loc);
 936 }
 937
 938 namespace llvm {
 939
 940 MCAsmParserExtension *createELFAsmParser() {
 941   return new ELFAsmParser;
 942 }
 943
 944 } // end namespace llvm