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/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, bool &IsComdat);
 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       if (getParser().discardLTOSymbol(Name)) {
 186         if (getLexer().is(AsmToken::EndOfStatement))
 187           break;
 188         continue;
 189       }
 190
 191       MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 192
 193       getStreamer().emitSymbolAttribute(Sym, Attr);
 194
 195       if (getLexer().is(AsmToken::EndOfStatement))
 196         break;
 197
 198       if (getLexer().isNot(AsmToken::Comma))
 199         return TokError("unexpected token in directive");
 200       Lex();
 201     }
 202   }
 203
 204   Lex();
 205   return false;
 206 }
 207
 208 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
 209                                       unsigned Flags, SectionKind Kind) {
 210   const MCExpr *Subsection = nullptr;
 211   if (getLexer().isNot(AsmToken::EndOfStatement)) {
 212     if (getParser().parseExpression(Subsection))
 213       return true;
 214   }
 215   Lex();
 216
 217   getStreamer().SwitchSection(getContext().getELFSection(Section, Type, Flags),
 218                               Subsection);
 219
 220   return false;
 221 }
 222
 223 bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
 224   StringRef Name;
 225   if (getParser().parseIdentifier(Name))
 226     return TokError("expected identifier in directive");
 227   MCSymbolELF *Sym = cast<MCSymbolELF>(getContext().getOrCreateSymbol(Name));
 228
 229   if (getLexer().isNot(AsmToken::Comma))
 230     return TokError("unexpected token in directive");
 231   Lex();
 232
 233   const MCExpr *Expr;
 234   if (getParser().parseExpression(Expr))
 235     return true;
 236
 237   if (getLexer().isNot(AsmToken::EndOfStatement))
 238     return TokError("unexpected token in directive");
 239   Lex();
 240
 241   getStreamer().emitELFSize(Sym, Expr);
 242   return false;
 243 }
 244
 245 bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
 246   // A section name can contain -, so we cannot just use
 247   // parseIdentifier.
 248   SMLoc FirstLoc = getLexer().getLoc();
 249   unsigned Size = 0;
 250
 251   if (getLexer().is(AsmToken::String)) {
 252     SectionName = getTok().getIdentifier();
 253     Lex();
 254     return false;
 255   }
 256
 257   while (!getParser().hasPendingError()) {
 258     SMLoc PrevLoc = getLexer().getLoc();
 259     if (getLexer().is(AsmToken::Comma) ||
 260       getLexer().is(AsmToken::EndOfStatement))
 261       break;
 262
 263     unsigned CurSize;
 264     if (getLexer().is(AsmToken::String)) {
 265       CurSize = getTok().getIdentifier().size() + 2;
 266       Lex();
 267     } else if (getLexer().is(AsmToken::Identifier)) {
 268       CurSize = getTok().getIdentifier().size();
 269       Lex();
 270     } else {
 271       CurSize = getTok().getString().size();
 272       Lex();
 273     }
 274     Size += CurSize;
 275     SectionName = StringRef(FirstLoc.getPointer(), Size);
 276
 277     // Make sure the following token is adjacent.
 278     if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
 279       break;
 280   }
 281   if (Size == 0)
 282     return true;
 283
 284   return false;
 285 }
 286
 287 static unsigned parseSectionFlags(StringRef flagsStr, 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       flags |= ELF::XCORE_SHF_CP_SECTION;
 322       break;
 323     case 'd':
 324       flags |= ELF::XCORE_SHF_DP_SECTION;
 325       break;
 326     case 'y':
 327       flags |= ELF::SHF_ARM_PURECODE;
 328       break;
 329     case 's':
 330       flags |= ELF::SHF_HEX_GPREL;
 331       break;
 332     case 'G':
 333       flags |= ELF::SHF_GROUP;
 334       break;
 335     case 'R':
 336       flags |= ELF::SHF_GNU_RETAIN;
 337       break;
 338     case '?':
 339       *UseLastGroup = true;
 340       break;
 341     default:
 342       return -1U;
 343     }
 344   }
 345
 346   return flags;
 347 }
 348
 349 unsigned ELFAsmParser::parseSunStyleSectionFlags() {
 350   unsigned flags = 0;
 351   while (getLexer().is(AsmToken::Hash)) {
 352     Lex(); // Eat the #.
 353
 354     if (!getLexer().is(AsmToken::Identifier))
 355       return -1U;
 356
 357     StringRef flagId = getTok().getIdentifier();
 358     if (flagId == "alloc")
 359       flags |= ELF::SHF_ALLOC;
 360     else if (flagId == "execinstr")
 361       flags |= ELF::SHF_EXECINSTR;
 362     else if (flagId == "write")
 363       flags |= ELF::SHF_WRITE;
 364     else if (flagId == "tls")
 365       flags |= ELF::SHF_TLS;
 366     else
 367       return -1U;
 368
 369     Lex(); // Eat the flag.
 370
 371     if (!getLexer().is(AsmToken::Comma))
 372         break;
 373     Lex(); // Eat the comma.
 374   }
 375   return flags;
 376 }
 377
 378
 379 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
 380   getStreamer().PushSection();
 381
 382   if (ParseSectionArguments(/*IsPush=*/true, loc)) {
 383     getStreamer().PopSection();
 384     return true;
 385   }
 386
 387   return false;
 388 }
 389
 390 bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
 391   if (!getStreamer().PopSection())
 392     return TokError(".popsection without corresponding .pushsection");
 393   return false;
 394 }
 395
 396 bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
 397   return ParseSectionArguments(/*IsPush=*/false, loc);
 398 }
 399
 400 bool ELFAsmParser::maybeParseSectionType(StringRef &TypeName) {
 401   MCAsmLexer &L = getLexer();
 402   if (L.isNot(AsmToken::Comma))
 403     return false;
 404   Lex();
 405   if (L.isNot(AsmToken::At) && L.isNot(AsmToken::Percent) &&
 406       L.isNot(AsmToken::String)) {
 407     if (L.getAllowAtInIdentifier())
 408       return TokError("expected '@<type>', '%<type>' or \"<type>\"");
 409     else
 410       return TokError("expected '%<type>' or \"<type>\"");
 411   }
 412   if (!L.is(AsmToken::String))
 413     Lex();
 414   if (L.is(AsmToken::Integer)) {
 415     TypeName = getTok().getString();
 416     Lex();
 417   } else if (getParser().parseIdentifier(TypeName))
 418     return TokError("expected identifier in directive");
 419   return false;
 420 }
 421
 422 bool ELFAsmParser::parseMergeSize(int64_t &Size) {
 423   if (getLexer().isNot(AsmToken::Comma))
 424     return TokError("expected the entry size");
 425   Lex();
 426   if (getParser().parseAbsoluteExpression(Size))
 427     return true;
 428   if (Size <= 0)
 429     return TokError("entry size must be positive");
 430   return false;
 431 }
 432
 433 bool ELFAsmParser::parseGroup(StringRef &GroupName, bool &IsComdat) {
 434   MCAsmLexer &L = getLexer();
 435   if (L.isNot(AsmToken::Comma))
 436     return TokError("expected group name");
 437   Lex();
 438   if (L.is(AsmToken::Integer)) {
 439     GroupName = getTok().getString();
 440     Lex();
 441   } else if (getParser().parseIdentifier(GroupName)) {
 442     return TokError("invalid group name");
 443   }
 444   if (L.is(AsmToken::Comma)) {
 445     Lex();
 446     StringRef Linkage;
 447     if (getParser().parseIdentifier(Linkage))
 448       return TokError("invalid linkage");
 449     if (Linkage != "comdat")
 450       return TokError("Linkage must be 'comdat'");
 451     IsComdat = true;
 452   } else {
 453     IsComdat = false;
 454   }
 455   return false;
 456 }
 457
 458 bool ELFAsmParser::parseLinkedToSym(MCSymbolELF *&LinkedToSym) {
 459   MCAsmLexer &L = getLexer();
 460   if (L.isNot(AsmToken::Comma))
 461     return TokError("expected linked-to symbol");
 462   Lex();
 463   StringRef Name;
 464   SMLoc StartLoc = L.getLoc();
 465   if (getParser().parseIdentifier(Name)) {
 466     if (getParser().getTok().getString() == "0") {
 467       getParser().Lex();
 468       LinkedToSym = nullptr;
 469       return false;
 470     }
 471     return TokError("invalid linked-to symbol");
 472   }
 473   LinkedToSym = dyn_cast_or_null<MCSymbolELF>(getContext().lookupSymbol(Name));
 474   if (!LinkedToSym || !LinkedToSym->isInSection())
 475     return Error(StartLoc, "linked-to symbol is not in a section: " + Name);
 476   return false;
 477 }
 478
 479 bool ELFAsmParser::maybeParseUniqueID(int64_t &UniqueID) {
 480   MCAsmLexer &L = getLexer();
 481   if (L.isNot(AsmToken::Comma))
 482     return false;
 483   Lex();
 484   StringRef UniqueStr;
 485   if (getParser().parseIdentifier(UniqueStr))
 486     return TokError("expected identifier in directive");
 487   if (UniqueStr != "unique")
 488     return TokError("expected 'unique'");
 489   if (L.isNot(AsmToken::Comma))
 490     return TokError("expected commma");
 491   Lex();
 492   if (getParser().parseAbsoluteExpression(UniqueID))
 493     return true;
 494   if (UniqueID < 0)
 495     return TokError("unique id must be positive");
 496   if (!isUInt<32>(UniqueID) || UniqueID == ~0U)
 497     return TokError("unique id is too large");
 498   return false;
 499 }
 500
 501 static bool hasPrefix(StringRef SectionName, StringRef Prefix) {
 502   return SectionName.startswith(Prefix) || SectionName == Prefix.drop_back();
 503 }
 504
 505 static bool allowSectionTypeMismatch(const Triple &TT, StringRef SectionName,
 506                                      unsigned Type) {
 507   if (TT.getArch() == Triple::x86_64) {
 508     // x86-64 psABI names SHT_X86_64_UNWIND as the canonical type for .eh_frame,
 509     // but GNU as emits SHT_PROGBITS .eh_frame for .cfi_* directives. Don't
 510     // error for SHT_PROGBITS .eh_frame
 511     return SectionName == ".eh_frame" && Type == ELF::SHT_PROGBITS;
 512   }
 513   if (TT.isMIPS()) {
 514     // MIPS .debug_* sections should have SHT_MIPS_DWARF section type to
 515     // distinguish among sections contain DWARF and ECOFF debug formats,
 516     // but in assembly files these sections have SHT_PROGBITS type.
 517     return hasPrefix(SectionName, ".debug_") && Type == ELF::SHT_PROGBITS;
 518   }
 519   return false;
 520 }
 521
 522 bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
 523   StringRef SectionName;
 524
 525   if (ParseSectionName(SectionName))
 526     return TokError("expected identifier in directive");
 527
 528   StringRef TypeName;
 529   int64_t Size = 0;
 530   StringRef GroupName;
 531   bool IsComdat = false;
 532   unsigned Flags = 0;
 533   unsigned extraFlags = 0;
 534   const MCExpr *Subsection = nullptr;
 535   bool UseLastGroup = false;
 536   MCSymbolELF *LinkedToSym = nullptr;
 537   int64_t UniqueID = ~0;
 538
 539   // Set the defaults first.
 540   if (hasPrefix(SectionName, ".rodata.") || SectionName == ".rodata1")
 541     Flags |= ELF::SHF_ALLOC;
 542   else if (SectionName == ".fini" || SectionName == ".init" ||
 543            hasPrefix(SectionName, ".text."))
 544     Flags |= ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
 545   else if (hasPrefix(SectionName, ".data.") || SectionName == ".data1" ||
 546            hasPrefix(SectionName, ".bss.") ||
 547            hasPrefix(SectionName, ".init_array.") ||
 548            hasPrefix(SectionName, ".fini_array.") ||
 549            hasPrefix(SectionName, ".preinit_array."))
 550     Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE;
 551   else if (hasPrefix(SectionName, ".tdata.") ||
 552            hasPrefix(SectionName, ".tbss."))
 553     Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_TLS;
 554
 555   if (getLexer().is(AsmToken::Comma)) {
 556     Lex();
 557
 558     if (IsPush && getLexer().isNot(AsmToken::String)) {
 559       if (getParser().parseExpression(Subsection))
 560         return true;
 561       if (getLexer().isNot(AsmToken::Comma))
 562         goto EndStmt;
 563       Lex();
 564     }
 565
 566     if (getLexer().isNot(AsmToken::String)) {
 567       if (!getContext().getAsmInfo()->usesSunStyleELFSectionSwitchSyntax()
 568           || getLexer().isNot(AsmToken::Hash))
 569         return TokError("expected string in directive");
 570       extraFlags = parseSunStyleSectionFlags();
 571     } else {
 572       StringRef FlagsStr = getTok().getStringContents();
 573       Lex();
 574       extraFlags = parseSectionFlags(FlagsStr, &UseLastGroup);
 575     }
 576
 577     if (extraFlags == -1U)
 578       return TokError("unknown flag");
 579     Flags |= extraFlags;
 580
 581     bool Mergeable = Flags & ELF::SHF_MERGE;
 582     bool Group = Flags & ELF::SHF_GROUP;
 583     if (Group && UseLastGroup)
 584       return TokError("Section cannot specifiy a group name while also acting "
 585                       "as a member of the last group");
 586
 587     if (maybeParseSectionType(TypeName))
 588       return true;
 589
 590     MCAsmLexer &L = getLexer();
 591     if (TypeName.empty()) {
 592       if (Mergeable)
 593         return TokError("Mergeable section must specify the type");
 594       if (Group)
 595         return TokError("Group section must specify the type");
 596       if (L.isNot(AsmToken::EndOfStatement))
 597         return TokError("unexpected token in directive");
 598     }
 599
 600     if (Mergeable)
 601       if (parseMergeSize(Size))
 602         return true;
 603     if (Group)
 604       if (parseGroup(GroupName, IsComdat))
 605         return true;
 606     if (Flags & ELF::SHF_LINK_ORDER)
 607       if (parseLinkedToSym(LinkedToSym))
 608         return true;
 609     if (maybeParseUniqueID(UniqueID))
 610       return true;
 611   }
 612
 613 EndStmt:
 614   if (getLexer().isNot(AsmToken::EndOfStatement))
 615     return TokError("unexpected token in directive");
 616   Lex();
 617
 618   unsigned Type = ELF::SHT_PROGBITS;
 619
 620   if (TypeName.empty()) {
 621     if (SectionName.startswith(".note"))
 622       Type = ELF::SHT_NOTE;
 623     else if (hasPrefix(SectionName, ".init_array."))
 624       Type = ELF::SHT_INIT_ARRAY;
 625     else if (hasPrefix(SectionName, ".bss."))
 626       Type = ELF::SHT_NOBITS;
 627     else if (hasPrefix(SectionName, ".tbss."))
 628       Type = ELF::SHT_NOBITS;
 629     else if (hasPrefix(SectionName, ".fini_array."))
 630       Type = ELF::SHT_FINI_ARRAY;
 631     else if (hasPrefix(SectionName, ".preinit_array."))
 632       Type = ELF::SHT_PREINIT_ARRAY;
 633   } else {
 634     if (TypeName == "init_array")
 635       Type = ELF::SHT_INIT_ARRAY;
 636     else if (TypeName == "fini_array")
 637       Type = ELF::SHT_FINI_ARRAY;
 638     else if (TypeName == "preinit_array")
 639       Type = ELF::SHT_PREINIT_ARRAY;
 640     else if (TypeName == "nobits")
 641       Type = ELF::SHT_NOBITS;
 642     else if (TypeName == "progbits")
 643       Type = ELF::SHT_PROGBITS;
 644     else if (TypeName == "note")
 645       Type = ELF::SHT_NOTE;
 646     else if (TypeName == "unwind")
 647       Type = ELF::SHT_X86_64_UNWIND;
 648     else if (TypeName == "llvm_odrtab")
 649       Type = ELF::SHT_LLVM_ODRTAB;
 650     else if (TypeName == "llvm_linker_options")
 651       Type = ELF::SHT_LLVM_LINKER_OPTIONS;
 652     else if (TypeName == "llvm_call_graph_profile")
 653       Type = ELF::SHT_LLVM_CALL_GRAPH_PROFILE;
 654     else if (TypeName == "llvm_dependent_libraries")
 655       Type = ELF::SHT_LLVM_DEPENDENT_LIBRARIES;
 656     else if (TypeName == "llvm_sympart")
 657       Type = ELF::SHT_LLVM_SYMPART;
 658     else if (TypeName == "llvm_bb_addr_map")
 659       Type = ELF::SHT_LLVM_BB_ADDR_MAP;
 660     else if (TypeName.getAsInteger(0, Type))
 661       return TokError("unknown section type");
 662   }
 663
 664   if (UseLastGroup) {
 665     MCSectionSubPair CurrentSection = getStreamer().getCurrentSection();
 666     if (const MCSectionELF *Section =
 667             cast_or_null<MCSectionELF>(CurrentSection.first))
 668       if (const MCSymbol *Group = Section->getGroup()) {
 669         GroupName = Group->getName();
 670         IsComdat = Section->isComdat();
 671         Flags |= ELF::SHF_GROUP;
 672       }
 673   }
 674
 675   MCSectionELF *Section =
 676       getContext().getELFSection(SectionName, Type, Flags, Size, GroupName,
 677                                  IsComdat, UniqueID, LinkedToSym);
 678   getStreamer().SwitchSection(Section, Subsection);
 679   if (Section->getType() != Type &&
 680       !allowSectionTypeMismatch(getContext().getTargetTriple(), SectionName,
 681                                 Type))
 682     Error(loc, "changed section type for " + SectionName + ", expected: 0x" +
 683                    utohexstr(Section->getType()));
 684   // Check that flags are used consistently. However, the GNU assembler permits
 685   // to leave out in subsequent uses of the same sections; for compatibility,
 686   // do likewise.
 687   if ((extraFlags || Size || !TypeName.empty()) && Section->getFlags() != Flags)
 688     Error(loc, "changed section flags for " + SectionName + ", expected: 0x" +
 689                    utohexstr(Section->getFlags()));
 690   if ((extraFlags || Size || !TypeName.empty()) &&
 691       Section->getEntrySize() != Size)
 692     Error(loc, "changed section entsize for " + SectionName +
 693                    ", expected: " + Twine(Section->getEntrySize()));
 694
 695   if (getContext().getGenDwarfForAssembly() &&
 696       (Section->getFlags() & ELF::SHF_ALLOC) &&
 697       (Section->getFlags() & ELF::SHF_EXECINSTR)) {
 698     bool InsertResult = getContext().addGenDwarfSection(Section);
 699     if (InsertResult) {
 700       if (getContext().getDwarfVersion() <= 2)
 701         Warning(loc, "DWARF2 only supports one section per compilation unit");
 702
 703       if (!Section->getBeginSymbol()) {
 704         MCSymbol *SectionStartSymbol = getContext().createTempSymbol();
 705         getStreamer().emitLabel(SectionStartSymbol);
 706         Section->setBeginSymbol(SectionStartSymbol);
 707       }
 708     }
 709   }
 710
 711   return false;
 712 }
 713
 714 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
 715   MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
 716   if (PreviousSection.first == nullptr)
 717       return TokError(".previous without corresponding .section");
 718   getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second);
 719
 720   return false;
 721 }
 722
 723 static MCSymbolAttr MCAttrForString(StringRef Type) {
 724   return StringSwitch<MCSymbolAttr>(Type)
 725           .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
 726           .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
 727           .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
 728           .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
 729           .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
 730           .Cases("STT_GNU_IFUNC", "gnu_indirect_function",
 731                  MCSA_ELF_TypeIndFunction)
 732           .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
 733           .Default(MCSA_Invalid);
 734 }
 735
 736 /// ParseDirectiveELFType
 737 ///  ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
 738 ///  ::= .type identifier , #attribute
 739 ///  ::= .type identifier , @attribute
 740 ///  ::= .type identifier , %attribute
 741 ///  ::= .type identifier , "attribute"
 742 bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
 743   StringRef Name;
 744   if (getParser().parseIdentifier(Name))
 745     return TokError("expected identifier in directive");
 746
 747   // Handle the identifier as the key symbol.
 748   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 749
 750   // NOTE the comma is optional in all cases.  It is only documented as being
 751   // optional in the first case, however, GAS will silently treat the comma as
 752   // optional in all cases.  Furthermore, although the documentation states that
 753   // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
 754   // accepts both the upper case name as well as the lower case aliases.
 755   if (getLexer().is(AsmToken::Comma))
 756     Lex();
 757
 758   if (getLexer().isNot(AsmToken::Identifier) &&
 759       getLexer().isNot(AsmToken::Hash) &&
 760       getLexer().isNot(AsmToken::Percent) &&
 761       getLexer().isNot(AsmToken::String)) {
 762     if (!getLexer().getAllowAtInIdentifier())
 763       return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', "
 764                       "'%<type>' or \"<type>\"");
 765     else if (getLexer().isNot(AsmToken::At))
 766       return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
 767                       "'%<type>' or \"<type>\"");
 768   }
 769
 770   if (getLexer().isNot(AsmToken::String) &&
 771       getLexer().isNot(AsmToken::Identifier))
 772     Lex();
 773
 774   SMLoc TypeLoc = getLexer().getLoc();
 775
 776   StringRef Type;
 777   if (getParser().parseIdentifier(Type))
 778     return TokError("expected symbol type in directive");
 779
 780   MCSymbolAttr Attr = MCAttrForString(Type);
 781   if (Attr == MCSA_Invalid)
 782     return Error(TypeLoc, "unsupported attribute in '.type' directive");
 783
 784   if (getLexer().isNot(AsmToken::EndOfStatement))
 785     return TokError("unexpected token in '.type' directive");
 786   Lex();
 787
 788   getStreamer().emitSymbolAttribute(Sym, Attr);
 789
 790   return false;
 791 }
 792
 793 /// ParseDirectiveIdent
 794 ///  ::= .ident string
 795 bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
 796   if (getLexer().isNot(AsmToken::String))
 797     return TokError("unexpected token in '.ident' directive");
 798
 799   StringRef Data = getTok().getIdentifier();
 800
 801   Lex();
 802
 803   if (getLexer().isNot(AsmToken::EndOfStatement))
 804     return TokError("unexpected token in '.ident' directive");
 805   Lex();
 806
 807   getStreamer().emitIdent(Data);
 808   return false;
 809 }
 810
 811 /// ParseDirectiveSymver
 812 ///  ::= .symver foo, bar2@zed
 813 bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
 814   StringRef OriginalName, Name, Action;
 815   if (getParser().parseIdentifier(OriginalName))
 816     return TokError("expected identifier in directive");
 817
 818   if (getLexer().isNot(AsmToken::Comma))
 819     return TokError("expected a comma");
 820
 821   // ARM assembly uses @ for a comment...
 822   // except when parsing the second parameter of the .symver directive.
 823   // Force the next symbol to allow @ in the identifier, which is
 824   // required for this directive and then reset it to its initial state.
 825   const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
 826   getLexer().setAllowAtInIdentifier(true);
 827   Lex();
 828   getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
 829
 830   if (getParser().parseIdentifier(Name))
 831     return TokError("expected identifier in directive");
 832
 833   if (Name.find('@') == StringRef::npos)
 834     return TokError("expected a '@' in the name");
 835   bool KeepOriginalSym = !Name.contains("@@@");
 836   if (parseOptionalToken(AsmToken::Comma)) {
 837     if (getParser().parseIdentifier(Action) || Action != "remove")
 838       return TokError("expected 'remove'");
 839     KeepOriginalSym = false;
 840   }
 841   (void)parseOptionalToken(AsmToken::EndOfStatement);
 842
 843   getStreamer().emitELFSymverDirective(
 844       getContext().getOrCreateSymbol(OriginalName), Name, KeepOriginalSym);
 845   return false;
 846 }
 847
 848 /// ParseDirectiveVersion
 849 ///  ::= .version string
 850 bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
 851   if (getLexer().isNot(AsmToken::String))
 852     return TokError("unexpected token in '.version' directive");
 853
 854   StringRef Data = getTok().getIdentifier();
 855
 856   Lex();
 857
 858   MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0);
 859
 860   getStreamer().PushSection();
 861   getStreamer().SwitchSection(Note);
 862   getStreamer().emitInt32(Data.size() + 1); // namesz
 863   getStreamer().emitInt32(0);               // descsz = 0 (no description).
 864   getStreamer().emitInt32(1);               // type = NT_VERSION
 865   getStreamer().emitBytes(Data);            // name
 866   getStreamer().emitInt8(0);                // NUL
 867   getStreamer().emitValueToAlignment(4);
 868   getStreamer().PopSection();
 869   return false;
 870 }
 871
 872 /// ParseDirectiveWeakref
 873 ///  ::= .weakref foo, bar
 874 bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
 875   // FIXME: Share code with the other alias building directives.
 876
 877   StringRef AliasName;
 878   if (getParser().parseIdentifier(AliasName))
 879     return TokError("expected identifier in directive");
 880
 881   if (getLexer().isNot(AsmToken::Comma))
 882     return TokError("expected a comma");
 883
 884   Lex();
 885
 886   StringRef Name;
 887   if (getParser().parseIdentifier(Name))
 888     return TokError("expected identifier in directive");
 889
 890   MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
 891
 892   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 893
 894   getStreamer().emitWeakReference(Alias, Sym);
 895   return false;
 896 }
 897
 898 bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) {
 899   const MCExpr *Subsection = nullptr;
 900   if (getLexer().isNot(AsmToken::EndOfStatement)) {
 901     if (getParser().parseExpression(Subsection))
 902      return true;
 903   }
 904
 905   if (getLexer().isNot(AsmToken::EndOfStatement))
 906     return TokError("unexpected token in directive");
 907
 908   Lex();
 909
 910   getStreamer().SubSection(Subsection);
 911   return false;
 912 }
 913
 914 bool ELFAsmParser::ParseDirectiveCGProfile(StringRef S, SMLoc Loc) {
 915   return MCAsmParserExtension::ParseDirectiveCGProfile(S, Loc);
 916 }
 917
 918 namespace llvm {
 919
 920 MCAsmParserExtension *createELFAsmParser() {
 921   return new ELFAsmParser;
 922 }
 923
 924 } // end namespace llvm