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
32using namespace llvm;
33
34namespace {
35
36class 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
48public:
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
154private:
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 parseMetadataSym(MCSymbolELF *&Associated);
162  bool maybeParseUniqueID(int64_t &UniqueID);
163};
164
165} // end anonymous namespace
166
167/// ParseDirectiveSymbolAttribute
168///  ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ]
169bool 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
202bool 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
217bool 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
239bool 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
281static 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
340unsigned 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
370bool 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
381bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
382  if (!getStreamer().PopSection())
383    return TokError(".popsection without corresponding .pushsection");
384  return false;
385}
386
387bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
388  return ParseSectionArguments(/*IsPush=*/false, loc);
389}
390
391bool 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
413bool 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
424bool 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
446bool ELFAsmParser::parseMetadataSym(MCSymbolELF *&Associated) {
447  MCAsmLexer &L = getLexer();
448  if (L.isNot(AsmToken::Comma))
449    return TokError("expected metadata symbol");
450  Lex();
451  StringRef Name;
452  if (getParser().parseIdentifier(Name))
453    return TokError("invalid metadata symbol");
454  Associated = dyn_cast_or_null<MCSymbolELF>(getContext().lookupSymbol(Name));
455  if (!Associated || !Associated->isInSection())
456    return TokError("symbol is not in a section: " + Name);
457  return false;
458}
459
460bool ELFAsmParser::maybeParseUniqueID(int64_t &UniqueID) {
461  MCAsmLexer &L = getLexer();
462  if (L.isNot(AsmToken::Comma))
463    return false;
464  Lex();
465  StringRef UniqueStr;
466  if (getParser().parseIdentifier(UniqueStr))
467    return TokError("expected identifier in directive");
468  if (UniqueStr != "unique")
469    return TokError("expected 'unique'");
470  if (L.isNot(AsmToken::Comma))
471    return TokError("expected commma");
472  Lex();
473  if (getParser().parseAbsoluteExpression(UniqueID))
474    return true;
475  if (UniqueID < 0)
476    return TokError("unique id must be positive");
477  if (!isUInt<32>(UniqueID) || UniqueID == ~0U)
478    return TokError("unique id is too large");
479  return false;
480}
481
482static bool hasPrefix(StringRef SectionName, StringRef Prefix) {
483  return SectionName.startswith(Prefix) || SectionName == Prefix.drop_back();
484}
485
486bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
487  StringRef SectionName;
488
489  if (ParseSectionName(SectionName))
490    return TokError("expected identifier in directive");
491
492  StringRef TypeName;
493  int64_t Size = 0;
494  StringRef GroupName;
495  unsigned Flags = 0;
496  const MCExpr *Subsection = nullptr;
497  bool UseLastGroup = false;
498  MCSymbolELF *Associated = nullptr;
499  int64_t UniqueID = ~0;
500
501  // Set the defaults first.
502  if (hasPrefix(SectionName, ".rodata.") || SectionName == ".rodata1")
503    Flags |= ELF::SHF_ALLOC;
504  else if (SectionName == ".fini" || SectionName == ".init" ||
505           hasPrefix(SectionName, ".text."))
506    Flags |= ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
507  else if (hasPrefix(SectionName, ".data.") || SectionName == ".data1" ||
508           hasPrefix(SectionName, ".bss.") ||
509           hasPrefix(SectionName, ".init_array.") ||
510           hasPrefix(SectionName, ".fini_array.") ||
511           hasPrefix(SectionName, ".preinit_array."))
512    Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE;
513  else if (hasPrefix(SectionName, ".tdata.") ||
514           hasPrefix(SectionName, ".tbss."))
515    Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_TLS;
516
517  if (getLexer().is(AsmToken::Comma)) {
518    Lex();
519
520    if (IsPush && getLexer().isNot(AsmToken::String)) {
521      if (getParser().parseExpression(Subsection))
522        return true;
523      if (getLexer().isNot(AsmToken::Comma))
524        goto EndStmt;
525      Lex();
526    }
527
528    unsigned extraFlags;
529
530    if (getLexer().isNot(AsmToken::String)) {
531      if (!getContext().getAsmInfo()->usesSunStyleELFSectionSwitchSyntax()
532          || getLexer().isNot(AsmToken::Hash))
533        return TokError("expected string in directive");
534      extraFlags = parseSunStyleSectionFlags();
535    } else {
536      StringRef FlagsStr = getTok().getStringContents();
537      Lex();
538      extraFlags = parseSectionFlags(FlagsStr, &UseLastGroup);
539    }
540
541    if (extraFlags == -1U)
542      return TokError("unknown flag");
543    Flags |= extraFlags;
544
545    bool Mergeable = Flags & ELF::SHF_MERGE;
546    bool Group = Flags & ELF::SHF_GROUP;
547    if (Group && UseLastGroup)
548      return TokError("Section cannot specifiy a group name while also acting "
549                      "as a member of the last group");
550
551    if (maybeParseSectionType(TypeName))
552      return true;
553
554    MCAsmLexer &L = getLexer();
555    if (TypeName.empty()) {
556      if (Mergeable)
557        return TokError("Mergeable section must specify the type");
558      if (Group)
559        return TokError("Group section must specify the type");
560      if (L.isNot(AsmToken::EndOfStatement))
561        return TokError("unexpected token in directive");
562    }
563
564    if (Mergeable)
565      if (parseMergeSize(Size))
566        return true;
567    if (Group)
568      if (parseGroup(GroupName))
569        return true;
570    if (Flags & ELF::SHF_LINK_ORDER)
571      if (parseMetadataSym(Associated))
572        return true;
573    if (maybeParseUniqueID(UniqueID))
574      return true;
575  }
576
577EndStmt:
578  if (getLexer().isNot(AsmToken::EndOfStatement))
579    return TokError("unexpected token in directive");
580  Lex();
581
582  unsigned Type = ELF::SHT_PROGBITS;
583
584  if (TypeName.empty()) {
585    if (SectionName.startswith(".note"))
586      Type = ELF::SHT_NOTE;
587    else if (hasPrefix(SectionName, ".init_array."))
588      Type = ELF::SHT_INIT_ARRAY;
589    else if (hasPrefix(SectionName, ".bss."))
590      Type = ELF::SHT_NOBITS;
591    else if (hasPrefix(SectionName, ".tbss."))
592      Type = ELF::SHT_NOBITS;
593    else if (hasPrefix(SectionName, ".fini_array."))
594      Type = ELF::SHT_FINI_ARRAY;
595    else if (hasPrefix(SectionName, ".preinit_array."))
596      Type = ELF::SHT_PREINIT_ARRAY;
597  } else {
598    if (TypeName == "init_array")
599      Type = ELF::SHT_INIT_ARRAY;
600    else if (TypeName == "fini_array")
601      Type = ELF::SHT_FINI_ARRAY;
602    else if (TypeName == "preinit_array")
603      Type = ELF::SHT_PREINIT_ARRAY;
604    else if (TypeName == "nobits")
605      Type = ELF::SHT_NOBITS;
606    else if (TypeName == "progbits")
607      Type = ELF::SHT_PROGBITS;
608    else if (TypeName == "note")
609      Type = ELF::SHT_NOTE;
610    else if (TypeName == "unwind")
611      Type = ELF::SHT_X86_64_UNWIND;
612    else if (TypeName == "llvm_odrtab")
613      Type = ELF::SHT_LLVM_ODRTAB;
614    else if (TypeName == "llvm_linker_options")
615      Type = ELF::SHT_LLVM_LINKER_OPTIONS;
616    else if (TypeName == "llvm_call_graph_profile")
617      Type = ELF::SHT_LLVM_CALL_GRAPH_PROFILE;
618    else if (TypeName == "llvm_dependent_libraries")
619      Type = ELF::SHT_LLVM_DEPENDENT_LIBRARIES;
620    else if (TypeName == "llvm_sympart")
621      Type = ELF::SHT_LLVM_SYMPART;
622    else if (TypeName.getAsInteger(0, Type))
623      return TokError("unknown section type");
624  }
625
626  if (UseLastGroup) {
627    MCSectionSubPair CurrentSection = getStreamer().getCurrentSection();
628    if (const MCSectionELF *Section =
629            cast_or_null<MCSectionELF>(CurrentSection.first))
630      if (const MCSymbol *Group = Section->getGroup()) {
631        GroupName = Group->getName();
632        Flags |= ELF::SHF_GROUP;
633      }
634  }
635
636  MCSection *ELFSection =
637      getContext().getELFSection(SectionName, Type, Flags, Size, GroupName,
638                                 UniqueID, Associated);
639  getStreamer().SwitchSection(ELFSection, Subsection);
640
641  if (getContext().getGenDwarfForAssembly()) {
642    bool InsertResult = getContext().addGenDwarfSection(ELFSection);
643    if (InsertResult) {
644      if (getContext().getDwarfVersion() <= 2)
645        Warning(loc, "DWARF2 only supports one section per compilation unit");
646
647      if (!ELFSection->getBeginSymbol()) {
648        MCSymbol *SectionStartSymbol = getContext().createTempSymbol();
649        getStreamer().EmitLabel(SectionStartSymbol);
650        ELFSection->setBeginSymbol(SectionStartSymbol);
651      }
652    }
653  }
654
655  return false;
656}
657
658bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
659  MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
660  if (PreviousSection.first == nullptr)
661      return TokError(".previous without corresponding .section");
662  getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second);
663
664  return false;
665}
666
667static MCSymbolAttr MCAttrForString(StringRef Type) {
668  return StringSwitch<MCSymbolAttr>(Type)
669          .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
670          .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
671          .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
672          .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
673          .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
674          .Cases("STT_GNU_IFUNC", "gnu_indirect_function",
675                 MCSA_ELF_TypeIndFunction)
676          .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
677          .Default(MCSA_Invalid);
678}
679
680/// ParseDirectiveELFType
681///  ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
682///  ::= .type identifier , #attribute
683///  ::= .type identifier , @attribute
684///  ::= .type identifier , %attribute
685///  ::= .type identifier , "attribute"
686bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
687  StringRef Name;
688  if (getParser().parseIdentifier(Name))
689    return TokError("expected identifier in directive");
690
691  // Handle the identifier as the key symbol.
692  MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
693
694  // NOTE the comma is optional in all cases.  It is only documented as being
695  // optional in the first case, however, GAS will silently treat the comma as
696  // optional in all cases.  Furthermore, although the documentation states that
697  // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
698  // accepts both the upper case name as well as the lower case aliases.
699  if (getLexer().is(AsmToken::Comma))
700    Lex();
701
702  if (getLexer().isNot(AsmToken::Identifier) &&
703      getLexer().isNot(AsmToken::Hash) &&
704      getLexer().isNot(AsmToken::Percent) &&
705      getLexer().isNot(AsmToken::String)) {
706    if (!getLexer().getAllowAtInIdentifier())
707      return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', "
708                      "'%<type>' or \"<type>\"");
709    else if (getLexer().isNot(AsmToken::At))
710      return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
711                      "'%<type>' or \"<type>\"");
712  }
713
714  if (getLexer().isNot(AsmToken::String) &&
715      getLexer().isNot(AsmToken::Identifier))
716    Lex();
717
718  SMLoc TypeLoc = getLexer().getLoc();
719
720  StringRef Type;
721  if (getParser().parseIdentifier(Type))
722    return TokError("expected symbol type in directive");
723
724  MCSymbolAttr Attr = MCAttrForString(Type);
725  if (Attr == MCSA_Invalid)
726    return Error(TypeLoc, "unsupported attribute in '.type' directive");
727
728  if (getLexer().isNot(AsmToken::EndOfStatement))
729    return TokError("unexpected token in '.type' directive");
730  Lex();
731
732  getStreamer().EmitSymbolAttribute(Sym, Attr);
733
734  return false;
735}
736
737/// ParseDirectiveIdent
738///  ::= .ident string
739bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
740  if (getLexer().isNot(AsmToken::String))
741    return TokError("unexpected token in '.ident' directive");
742
743  StringRef Data = getTok().getIdentifier();
744
745  Lex();
746
747  if (getLexer().isNot(AsmToken::EndOfStatement))
748    return TokError("unexpected token in '.ident' directive");
749  Lex();
750
751  getStreamer().EmitIdent(Data);
752  return false;
753}
754
755/// ParseDirectiveSymver
756///  ::= .symver foo, bar2@zed
757bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
758  StringRef Name;
759  if (getParser().parseIdentifier(Name))
760    return TokError("expected identifier in directive");
761
762  if (getLexer().isNot(AsmToken::Comma))
763    return TokError("expected a comma");
764
765  // ARM assembly uses @ for a comment...
766  // except when parsing the second parameter of the .symver directive.
767  // Force the next symbol to allow @ in the identifier, which is
768  // required for this directive and then reset it to its initial state.
769  const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
770  getLexer().setAllowAtInIdentifier(true);
771  Lex();
772  getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
773
774  StringRef AliasName;
775  if (getParser().parseIdentifier(AliasName))
776    return TokError("expected identifier in directive");
777
778  if (AliasName.find('@') == StringRef::npos)
779    return TokError("expected a '@' in the name");
780
781  MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
782  getStreamer().emitELFSymverDirective(AliasName, Sym);
783  return false;
784}
785
786/// ParseDirectiveVersion
787///  ::= .version string
788bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
789  if (getLexer().isNot(AsmToken::String))
790    return TokError("unexpected token in '.version' directive");
791
792  StringRef Data = getTok().getIdentifier();
793
794  Lex();
795
796  MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0);
797
798  getStreamer().PushSection();
799  getStreamer().SwitchSection(Note);
800  getStreamer().EmitIntValue(Data.size()+1, 4); // namesz.
801  getStreamer().EmitIntValue(0, 4);             // descsz = 0 (no description).
802  getStreamer().EmitIntValue(1, 4);             // type = NT_VERSION.
803  getStreamer().EmitBytes(Data);                // name.
804  getStreamer().EmitIntValue(0, 1);             // terminate the string.
805  getStreamer().EmitValueToAlignment(4);        // ensure 4 byte alignment.
806  getStreamer().PopSection();
807  return false;
808}
809
810/// ParseDirectiveWeakref
811///  ::= .weakref foo, bar
812bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
813  // FIXME: Share code with the other alias building directives.
814
815  StringRef AliasName;
816  if (getParser().parseIdentifier(AliasName))
817    return TokError("expected identifier in directive");
818
819  if (getLexer().isNot(AsmToken::Comma))
820    return TokError("expected a comma");
821
822  Lex();
823
824  StringRef Name;
825  if (getParser().parseIdentifier(Name))
826    return TokError("expected identifier in directive");
827
828  MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
829
830  MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
831
832  getStreamer().EmitWeakReference(Alias, Sym);
833  return false;
834}
835
836bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) {
837  const MCExpr *Subsection = nullptr;
838  if (getLexer().isNot(AsmToken::EndOfStatement)) {
839    if (getParser().parseExpression(Subsection))
840     return true;
841  }
842
843  if (getLexer().isNot(AsmToken::EndOfStatement))
844    return TokError("unexpected token in directive");
845
846  Lex();
847
848  getStreamer().SubSection(Subsection);
849  return false;
850}
851
852/// ParseDirectiveCGProfile
853///  ::= .cg_profile identifier, identifier, <number>
854bool ELFAsmParser::ParseDirectiveCGProfile(StringRef, SMLoc) {
855  StringRef From;
856  SMLoc FromLoc = getLexer().getLoc();
857  if (getParser().parseIdentifier(From))
858    return TokError("expected identifier in directive");
859
860  if (getLexer().isNot(AsmToken::Comma))
861    return TokError("expected a comma");
862  Lex();
863
864  StringRef To;
865  SMLoc ToLoc = getLexer().getLoc();
866  if (getParser().parseIdentifier(To))
867    return TokError("expected identifier in directive");
868
869  if (getLexer().isNot(AsmToken::Comma))
870    return TokError("expected a comma");
871  Lex();
872
873  int64_t Count;
874  if (getParser().parseIntToken(
875          Count, "expected integer count in '.cg_profile' directive"))
876    return true;
877
878  if (getLexer().isNot(AsmToken::EndOfStatement))
879    return TokError("unexpected token in directive");
880
881  MCSymbol *FromSym = getContext().getOrCreateSymbol(From);
882  MCSymbol *ToSym = getContext().getOrCreateSymbol(To);
883
884  getStreamer().emitCGProfileEntry(
885      MCSymbolRefExpr::create(FromSym, MCSymbolRefExpr::VK_None, getContext(),
886                              FromLoc),
887      MCSymbolRefExpr::create(ToSym, MCSymbolRefExpr::VK_None, getContext(),
888                              ToLoc),
889      Count);
890  return false;
891}
892
893namespace llvm {
894
895MCAsmParserExtension *createELFAsmParser() {
896  return new ELFAsmParser;
897}
898
899} // end namespace llvm
900