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/ScopeExit.h"
10#include "llvm/ADT/StringExtras.h"
11#include "llvm/ADT/StringRef.h"
12#include "llvm/ADT/StringSwitch.h"
13#include "llvm/BinaryFormat/ELF.h"
14#include "llvm/MC/MCAsmInfo.h"
15#include "llvm/MC/MCContext.h"
16#include "llvm/MC/MCDirectives.h"
17#include "llvm/MC/MCParser/AsmLexer.h"
18#include "llvm/MC/MCParser/MCAsmParser.h"
19#include "llvm/MC/MCParser/MCAsmParserExtension.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/SMLoc.h"
26#include <cassert>
27#include <cstdint>
28
29using namespace llvm;
30
31namespace {
32
33class ELFAsmParser : public MCAsmParserExtension {
34 template<bool (ELFAsmParser::*HandlerMethod)(StringRef, SMLoc)>
35 void addDirectiveHandler(StringRef Directive) {
36 MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair(
37 this, HandleDirective<ELFAsmParser, HandlerMethod>);
38
39 getParser().addDirectiveHandler(Directive, Handler);
40 }
41
42 bool parseSectionSwitch(StringRef Section, unsigned Type, unsigned Flags,
43 SectionKind Kind);
44
45public:
46 ELFAsmParser() { BracketExpressionsSupported = true; }
47
48 void Initialize(MCAsmParser &Parser) override {
49 // Call the base implementation.
50 this->MCAsmParserExtension::Initialize(Parser);
51
52 addDirectiveHandler<&ELFAsmParser::parseSectionDirectiveData>(Directive: ".data");
53 addDirectiveHandler<&ELFAsmParser::parseSectionDirectiveText>(Directive: ".text");
54 addDirectiveHandler<&ELFAsmParser::parseSectionDirectiveBSS>(Directive: ".bss");
55 addDirectiveHandler<&ELFAsmParser::parseSectionDirectiveRoData>(Directive: ".rodata");
56 addDirectiveHandler<&ELFAsmParser::parseSectionDirectiveTData>(Directive: ".tdata");
57 addDirectiveHandler<&ELFAsmParser::parseSectionDirectiveTBSS>(Directive: ".tbss");
58 addDirectiveHandler<&ELFAsmParser::parseDirectiveSection>(Directive: ".section");
59 addDirectiveHandler<
60 &ELFAsmParser::parseDirectivePushSection>(Directive: ".pushsection");
61 addDirectiveHandler<&ELFAsmParser::parseDirectivePopSection>(Directive: ".popsection");
62 addDirectiveHandler<&ELFAsmParser::parseDirectiveSize>(Directive: ".size");
63 addDirectiveHandler<&ELFAsmParser::parseDirectivePrevious>(Directive: ".previous");
64 addDirectiveHandler<&ELFAsmParser::parseDirectiveType>(Directive: ".type");
65 addDirectiveHandler<&ELFAsmParser::parseDirectiveIdent>(Directive: ".ident");
66 addDirectiveHandler<&ELFAsmParser::parseDirectiveSymver>(Directive: ".symver");
67 addDirectiveHandler<&ELFAsmParser::parseDirectiveVersion>(Directive: ".version");
68 addDirectiveHandler<&ELFAsmParser::parseDirectiveWeakref>(Directive: ".weakref");
69 addDirectiveHandler<&ELFAsmParser::parseDirectiveSymbolAttribute>(Directive: ".weak");
70 addDirectiveHandler<&ELFAsmParser::parseDirectiveSymbolAttribute>(Directive: ".local");
71 addDirectiveHandler<
72 &ELFAsmParser::parseDirectiveSymbolAttribute>(Directive: ".protected");
73 addDirectiveHandler<
74 &ELFAsmParser::parseDirectiveSymbolAttribute>(Directive: ".internal");
75 addDirectiveHandler<
76 &ELFAsmParser::parseDirectiveSymbolAttribute>(Directive: ".hidden");
77 addDirectiveHandler<&ELFAsmParser::parseDirectiveSubsection>(Directive: ".subsection");
78 addDirectiveHandler<&ELFAsmParser::parseDirectiveCGProfile>(Directive: ".cg_profile");
79 }
80
81 // FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
82 // the best way for us to get access to it?
83 bool parseSectionDirectiveData(StringRef, SMLoc) {
84 return parseSectionSwitch(Section: ".data", Type: ELF::SHT_PROGBITS,
85 Flags: ELF::SHF_WRITE | ELF::SHF_ALLOC,
86 Kind: SectionKind::getData());
87 }
88 bool parseSectionDirectiveText(StringRef, SMLoc) {
89 return parseSectionSwitch(Section: ".text", Type: ELF::SHT_PROGBITS,
90 Flags: ELF::SHF_EXECINSTR |
91 ELF::SHF_ALLOC, Kind: SectionKind::getText());
92 }
93 bool parseSectionDirectiveBSS(StringRef, SMLoc) {
94 return parseSectionSwitch(Section: ".bss", Type: ELF::SHT_NOBITS,
95 Flags: ELF::SHF_WRITE |
96 ELF::SHF_ALLOC, Kind: SectionKind::getBSS());
97 }
98 bool parseSectionDirectiveRoData(StringRef, SMLoc) {
99 return parseSectionSwitch(Section: ".rodata", Type: ELF::SHT_PROGBITS,
100 Flags: ELF::SHF_ALLOC,
101 Kind: SectionKind::getReadOnly());
102 }
103 bool parseSectionDirectiveTData(StringRef, SMLoc) {
104 return parseSectionSwitch(Section: ".tdata", Type: ELF::SHT_PROGBITS,
105 Flags: ELF::SHF_ALLOC |
106 ELF::SHF_TLS | ELF::SHF_WRITE,
107 Kind: SectionKind::getThreadData());
108 }
109 bool parseSectionDirectiveTBSS(StringRef, SMLoc) {
110 return parseSectionSwitch(Section: ".tbss", Type: ELF::SHT_NOBITS,
111 Flags: ELF::SHF_ALLOC |
112 ELF::SHF_TLS | ELF::SHF_WRITE,
113 Kind: SectionKind::getThreadBSS());
114 }
115 bool parseDirectivePushSection(StringRef, SMLoc);
116 bool parseDirectivePopSection(StringRef, SMLoc);
117 bool parseDirectiveSection(StringRef, SMLoc);
118 bool parseDirectiveSize(StringRef, SMLoc);
119 bool parseDirectivePrevious(StringRef, SMLoc);
120 bool parseDirectiveType(StringRef, SMLoc);
121 bool parseDirectiveIdent(StringRef, SMLoc);
122 bool parseDirectiveSymver(StringRef, SMLoc);
123 bool parseDirectiveVersion(StringRef, SMLoc);
124 bool parseDirectiveWeakref(StringRef, SMLoc);
125 bool parseDirectiveSymbolAttribute(StringRef, SMLoc);
126 bool parseDirectiveSubsection(StringRef, SMLoc);
127 bool parseDirectiveCGProfile(StringRef, SMLoc);
128
129private:
130 bool parseSectionName(StringRef &SectionName);
131 bool parseSectionArguments(bool IsPush, SMLoc loc);
132 unsigned parseSunStyleSectionFlags();
133 bool maybeParseSectionType(StringRef &TypeName);
134 bool parseMergeSize(int64_t &Size);
135 bool parseGroup(StringRef &GroupName, bool &IsComdat);
136 bool parseLinkedToSym(MCSymbolELF *&LinkedToSym);
137};
138
139} // end anonymous namespace
140
141/// parseDirectiveSymbolAttribute
142/// ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ]
143bool ELFAsmParser::parseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
144 MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
145 .Case(S: ".weak", Value: MCSA_Weak)
146 .Case(S: ".local", Value: MCSA_Local)
147 .Case(S: ".hidden", Value: MCSA_Hidden)
148 .Case(S: ".internal", Value: MCSA_Internal)
149 .Case(S: ".protected", Value: MCSA_Protected)
150 .Default(Value: MCSA_Invalid);
151 assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
152 if (getLexer().isNot(K: AsmToken::EndOfStatement)) {
153 while (true) {
154 StringRef Name;
155
156 if (getParser().parseIdentifier(Res&: Name))
157 return TokError(Msg: "expected identifier");
158
159 if (getParser().discardLTOSymbol(Name)) {
160 if (getLexer().is(K: AsmToken::EndOfStatement))
161 break;
162 continue;
163 }
164
165 MCSymbol *Sym = getContext().parseSymbol(Name);
166
167 getStreamer().emitSymbolAttribute(Symbol: Sym, Attribute: Attr);
168
169 if (getLexer().is(K: AsmToken::EndOfStatement))
170 break;
171
172 if (getLexer().isNot(K: AsmToken::Comma))
173 return TokError(Msg: "expected comma");
174 Lex();
175 }
176 }
177
178 Lex();
179 return false;
180}
181
182bool ELFAsmParser::parseSectionSwitch(StringRef Section, unsigned Type,
183 unsigned Flags, SectionKind Kind) {
184 const MCExpr *Subsection = nullptr;
185 if (getLexer().isNot(K: AsmToken::EndOfStatement)) {
186 if (getParser().parseExpression(Res&: Subsection))
187 return true;
188 }
189 Lex();
190
191 getStreamer().switchSection(Section: getContext().getELFSection(Section, Type, Flags),
192 Subsection);
193
194 return false;
195}
196
197bool ELFAsmParser::parseDirectiveSize(StringRef, SMLoc) {
198 MCSymbol *Sym;
199 if (getParser().parseSymbol(Res&: Sym))
200 return TokError(Msg: "expected identifier");
201
202 if (getLexer().isNot(K: AsmToken::Comma))
203 return TokError(Msg: "expected comma");
204 Lex();
205
206 const MCExpr *Expr;
207 if (getParser().parseExpression(Res&: Expr))
208 return true;
209
210 if (getLexer().isNot(K: AsmToken::EndOfStatement))
211 return TokError(Msg: "unexpected token");
212 Lex();
213
214 getStreamer().emitELFSize(Symbol: Sym, Value: Expr);
215 return false;
216}
217
218bool ELFAsmParser::parseSectionName(StringRef &SectionName) {
219 // A section name can contain -, so we cannot just use
220 // parseIdentifier.
221 SMLoc FirstLoc = getLexer().getLoc();
222 unsigned Size = 0;
223
224 if (getLexer().is(K: AsmToken::String)) {
225 SectionName = getTok().getIdentifier();
226 Lex();
227 return false;
228 }
229
230 while (!getParser().hasPendingError()) {
231 SMLoc PrevLoc = getLexer().getLoc();
232 if (getLexer().is(K: AsmToken::Comma) ||
233 getLexer().is(K: AsmToken::EndOfStatement))
234 break;
235
236 unsigned CurSize;
237 if (getLexer().is(K: AsmToken::String)) {
238 CurSize = getTok().getIdentifier().size() + 2;
239 Lex();
240 } else if (getLexer().is(K: AsmToken::Identifier)) {
241 CurSize = getTok().getIdentifier().size();
242 Lex();
243 } else {
244 CurSize = getTok().getString().size();
245 Lex();
246 }
247 Size += CurSize;
248 SectionName = StringRef(FirstLoc.getPointer(), Size);
249
250 // Make sure the following token is adjacent.
251 if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
252 break;
253 }
254 if (Size == 0)
255 return true;
256
257 return false;
258}
259
260static unsigned parseSectionFlags(const Triple &TT, StringRef flagsStr,
261 bool *UseLastGroup) {
262 unsigned flags = 0;
263
264 // If a valid numerical value is set for the section flag, use it verbatim
265 if (!flagsStr.getAsInteger(Radix: 0, Result&: flags))
266 return flags;
267
268 for (char i : flagsStr) {
269 switch (i) {
270 case 'a':
271 flags |= ELF::SHF_ALLOC;
272 break;
273 case 'e':
274 flags |= ELF::SHF_EXCLUDE;
275 break;
276 case 'x':
277 flags |= ELF::SHF_EXECINSTR;
278 break;
279 case 'w':
280 flags |= ELF::SHF_WRITE;
281 break;
282 case 'o':
283 flags |= ELF::SHF_LINK_ORDER;
284 break;
285 case 'M':
286 flags |= ELF::SHF_MERGE;
287 break;
288 case 'S':
289 flags |= ELF::SHF_STRINGS;
290 break;
291 case 'T':
292 flags |= ELF::SHF_TLS;
293 break;
294 case 'c':
295 if (TT.getArch() != Triple::xcore)
296 return -1U;
297 flags |= ELF::XCORE_SHF_CP_SECTION;
298 break;
299 case 'd':
300 if (TT.getArch() != Triple::xcore)
301 return -1U;
302 flags |= ELF::XCORE_SHF_DP_SECTION;
303 break;
304 case 'y':
305 if (TT.isARM() || TT.isThumb())
306 flags |= ELF::SHF_ARM_PURECODE;
307 else if (TT.isAArch64())
308 flags |= ELF::SHF_AARCH64_PURECODE;
309 else
310 return -1U;
311 break;
312 case 's':
313 if (TT.getArch() != Triple::hexagon)
314 return -1U;
315 flags |= ELF::SHF_HEX_GPREL;
316 break;
317 case 'G':
318 flags |= ELF::SHF_GROUP;
319 break;
320 case 'l':
321 if (TT.getArch() != Triple::x86_64)
322 return -1U;
323 flags |= ELF::SHF_X86_64_LARGE;
324 break;
325 case 'R':
326 if (TT.isOSSolaris())
327 flags |= ELF::SHF_SUNW_NODISCARD;
328 else
329 flags |= ELF::SHF_GNU_RETAIN;
330 break;
331 case '?':
332 *UseLastGroup = true;
333 break;
334 default:
335 return -1U;
336 }
337 }
338
339 return flags;
340}
341
342unsigned ELFAsmParser::parseSunStyleSectionFlags() {
343 unsigned flags = 0;
344 while (getLexer().is(K: AsmToken::Hash)) {
345 Lex(); // Eat the #.
346
347 if (!getLexer().is(K: AsmToken::Identifier))
348 return -1U;
349
350 StringRef flagId = getTok().getIdentifier();
351 if (flagId == "alloc")
352 flags |= ELF::SHF_ALLOC;
353 else if (flagId == "execinstr")
354 flags |= ELF::SHF_EXECINSTR;
355 else if (flagId == "write")
356 flags |= ELF::SHF_WRITE;
357 else if (flagId == "tls")
358 flags |= ELF::SHF_TLS;
359 else
360 return -1U;
361
362 Lex(); // Eat the flag.
363
364 if (!getLexer().is(K: AsmToken::Comma))
365 break;
366 Lex(); // Eat the comma.
367 }
368 return flags;
369}
370
371
372bool ELFAsmParser::parseDirectivePushSection(StringRef s, SMLoc loc) {
373 getStreamer().pushSection();
374
375 if (parseSectionArguments(/*IsPush=*/true, loc)) {
376 getStreamer().popSection();
377 return true;
378 }
379
380 return false;
381}
382
383bool ELFAsmParser::parseDirectivePopSection(StringRef, SMLoc) {
384 if (!getStreamer().popSection())
385 return TokError(Msg: ".popsection without corresponding .pushsection");
386 return false;
387}
388
389bool ELFAsmParser::parseDirectiveSection(StringRef, SMLoc loc) {
390 return parseSectionArguments(/*IsPush=*/false, loc);
391}
392
393bool ELFAsmParser::maybeParseSectionType(StringRef &TypeName) {
394 AsmLexer &L = getLexer();
395 if (L.isNot(K: AsmToken::Comma))
396 return false;
397 Lex();
398 if (L.isNot(K: AsmToken::At) && L.isNot(K: AsmToken::Percent) &&
399 L.isNot(K: AsmToken::String)) {
400 if (getContext().getAsmInfo()->getCommentString().starts_with(Prefix: '@'))
401 return TokError(Msg: "expected '%<type>' or \"<type>\"");
402 else
403 return TokError(Msg: "expected '@<type>', '%<type>' or \"<type>\"");
404 }
405 if (!L.is(K: AsmToken::String))
406 Lex();
407 if (L.is(K: AsmToken::Integer)) {
408 TypeName = getTok().getString();
409 Lex();
410 } else if (getParser().parseIdentifier(Res&: TypeName))
411 return TokError(Msg: "expected identifier");
412 return false;
413}
414
415bool ELFAsmParser::parseMergeSize(int64_t &Size) {
416 if (getLexer().isNot(K: AsmToken::Comma))
417 return TokError(Msg: "expected the entry size");
418 Lex();
419 if (getParser().parseAbsoluteExpression(Res&: Size))
420 return true;
421 if (Size <= 0)
422 return TokError(Msg: "entry size must be positive");
423 return false;
424}
425
426bool ELFAsmParser::parseGroup(StringRef &GroupName, bool &IsComdat) {
427 AsmLexer &L = getLexer();
428 if (L.isNot(K: AsmToken::Comma))
429 return TokError(Msg: "expected group name");
430 Lex();
431 if (L.is(K: AsmToken::Integer)) {
432 GroupName = getTok().getString();
433 Lex();
434 } else if (getParser().parseIdentifier(Res&: GroupName)) {
435 return TokError(Msg: "invalid group name");
436 }
437 if (L.is(K: AsmToken::Comma)) {
438 Lex();
439 StringRef Linkage;
440 if (getParser().parseIdentifier(Res&: Linkage))
441 return TokError(Msg: "invalid linkage");
442 if (Linkage != "comdat")
443 return TokError(Msg: "Linkage must be 'comdat'");
444 IsComdat = true;
445 } else {
446 IsComdat = false;
447 }
448 return false;
449}
450
451bool ELFAsmParser::parseLinkedToSym(MCSymbolELF *&LinkedToSym) {
452 AsmLexer &L = getLexer();
453 if (L.isNot(K: AsmToken::Comma))
454 return TokError(Msg: "expected linked-to symbol");
455 Lex();
456 StringRef Name;
457 SMLoc StartLoc = L.getLoc();
458 if (getParser().parseIdentifier(Res&: Name)) {
459 if (getParser().getTok().getString() == "0") {
460 getParser().Lex();
461 LinkedToSym = nullptr;
462 return false;
463 }
464 return TokError(Msg: "invalid linked-to symbol");
465 }
466 LinkedToSym = static_cast<MCSymbolELF *>(getContext().lookupSymbol(Name));
467 if (!LinkedToSym || !LinkedToSym->isInSection())
468 return Error(L: StartLoc, Msg: "linked-to symbol is not in a section: " + Name);
469 return false;
470}
471
472static bool hasPrefix(StringRef SectionName, StringRef Prefix) {
473 return SectionName.consume_front(Prefix) &&
474 (SectionName.empty() || SectionName[0] == '.');
475}
476
477static bool allowSectionTypeMismatch(const Triple &TT, StringRef SectionName,
478 unsigned Type) {
479 if (TT.getArch() == Triple::x86_64) {
480 // x86-64 psABI names SHT_X86_64_UNWIND as the canonical type for .eh_frame,
481 // but GNU as emits SHT_PROGBITS .eh_frame for .cfi_* directives. Don't
482 // error for SHT_PROGBITS .eh_frame
483 return SectionName == ".eh_frame" && Type == ELF::SHT_PROGBITS;
484 }
485 if (TT.isMIPS()) {
486 // MIPS .debug_* sections should have SHT_MIPS_DWARF section type to
487 // distinguish among sections contain DWARF and ECOFF debug formats,
488 // but in assembly files these sections have SHT_PROGBITS type.
489 return SectionName.starts_with(Prefix: ".debug_") && Type == ELF::SHT_PROGBITS;
490 }
491 return false;
492}
493
494bool ELFAsmParser::parseSectionArguments(bool IsPush, SMLoc loc) {
495 StringRef SectionName;
496
497 if (parseSectionName(SectionName))
498 return TokError(Msg: "expected identifier");
499
500 StringRef TypeName;
501 int64_t Size = 0;
502 StringRef GroupName;
503 bool IsComdat = false;
504 unsigned Flags = 0;
505 unsigned extraFlags = 0;
506 const MCExpr *Subsection = nullptr;
507 bool UseLastGroup = false;
508 MCSymbolELF *LinkedToSym = nullptr;
509 int64_t UniqueID = ~0;
510
511 // Set the defaults first.
512 if (hasPrefix(SectionName, Prefix: ".rodata") || SectionName == ".rodata1")
513 Flags |= ELF::SHF_ALLOC;
514 else if (SectionName == ".fini" || SectionName == ".init" ||
515 hasPrefix(SectionName, Prefix: ".text"))
516 Flags |= ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
517 else if (hasPrefix(SectionName, Prefix: ".data") || SectionName == ".data1" ||
518 hasPrefix(SectionName, Prefix: ".bss") ||
519 hasPrefix(SectionName, Prefix: ".init_array") ||
520 hasPrefix(SectionName, Prefix: ".fini_array") ||
521 hasPrefix(SectionName, Prefix: ".preinit_array"))
522 Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE;
523 else if (hasPrefix(SectionName, Prefix: ".tdata") || hasPrefix(SectionName, Prefix: ".tbss"))
524 Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_TLS;
525
526 if (getLexer().is(K: AsmToken::Comma)) {
527 Lex();
528
529 if (IsPush && getLexer().isNot(K: AsmToken::String)) {
530 if (getParser().parseExpression(Res&: Subsection))
531 return true;
532 if (getLexer().isNot(K: AsmToken::Comma))
533 goto EndStmt;
534 Lex();
535 }
536
537 if (getLexer().isNot(K: AsmToken::String)) {
538 if (getLexer().isNot(K: AsmToken::Hash))
539 return TokError(Msg: "expected string");
540 extraFlags = parseSunStyleSectionFlags();
541 } else {
542 StringRef FlagsStr = getTok().getStringContents();
543 Lex();
544 extraFlags = parseSectionFlags(TT: getContext().getTargetTriple(), flagsStr: FlagsStr,
545 UseLastGroup: &UseLastGroup);
546 }
547
548 if (extraFlags == -1U)
549 return TokError(Msg: "unknown flag");
550 Flags |= extraFlags;
551
552 bool Mergeable = Flags & ELF::SHF_MERGE;
553 bool Group = Flags & ELF::SHF_GROUP;
554 if (Group && UseLastGroup)
555 return TokError(Msg: "Section cannot specifiy a group name while also acting "
556 "as a member of the last group");
557
558 if (maybeParseSectionType(TypeName))
559 return true;
560
561 AsmLexer &L = getLexer();
562 if (TypeName.empty()) {
563 if (Mergeable)
564 return TokError(Msg: "Mergeable section must specify the type");
565 if (Group)
566 return TokError(Msg: "Group section must specify the type");
567 if (L.isNot(K: AsmToken::EndOfStatement))
568 return TokError(Msg: "expected end of directive");
569 }
570
571 if (Mergeable || TypeName == "llvm_cfi_jump_table")
572 if (parseMergeSize(Size))
573 return true;
574 if (Flags & ELF::SHF_LINK_ORDER)
575 if (parseLinkedToSym(LinkedToSym))
576 return true;
577 if (Group)
578 if (parseGroup(GroupName, IsComdat))
579 return true;
580 if (maybeParseUniqueID(UniqueID))
581 return true;
582 }
583
584EndStmt:
585 if (getLexer().isNot(K: AsmToken::EndOfStatement))
586 return TokError(Msg: "expected end of directive");
587 Lex();
588
589 unsigned Type = ELF::SHT_PROGBITS;
590
591 if (TypeName.empty()) {
592 if (SectionName.starts_with(Prefix: ".note"))
593 Type = ELF::SHT_NOTE;
594 else if (hasPrefix(SectionName, Prefix: ".init_array"))
595 Type = ELF::SHT_INIT_ARRAY;
596 else if (hasPrefix(SectionName, Prefix: ".bss"))
597 Type = ELF::SHT_NOBITS;
598 else if (hasPrefix(SectionName, Prefix: ".tbss"))
599 Type = ELF::SHT_NOBITS;
600 else if (hasPrefix(SectionName, Prefix: ".fini_array"))
601 Type = ELF::SHT_FINI_ARRAY;
602 else if (hasPrefix(SectionName, Prefix: ".preinit_array"))
603 Type = ELF::SHT_PREINIT_ARRAY;
604 } else {
605 if (TypeName == "init_array")
606 Type = ELF::SHT_INIT_ARRAY;
607 else if (TypeName == "fini_array")
608 Type = ELF::SHT_FINI_ARRAY;
609 else if (TypeName == "preinit_array")
610 Type = ELF::SHT_PREINIT_ARRAY;
611 else if (TypeName == "nobits")
612 Type = ELF::SHT_NOBITS;
613 else if (TypeName == "progbits")
614 Type = ELF::SHT_PROGBITS;
615 else if (TypeName == "note")
616 Type = ELF::SHT_NOTE;
617 else if (TypeName == "unwind")
618 Type = ELF::SHT_X86_64_UNWIND;
619 else if (TypeName == "llvm_odrtab")
620 Type = ELF::SHT_LLVM_ODRTAB;
621 else if (TypeName == "llvm_linker_options")
622 Type = ELF::SHT_LLVM_LINKER_OPTIONS;
623 else if (TypeName == "llvm_call_graph_profile")
624 Type = ELF::SHT_LLVM_CALL_GRAPH_PROFILE;
625 else if (TypeName == "llvm_dependent_libraries")
626 Type = ELF::SHT_LLVM_DEPENDENT_LIBRARIES;
627 else if (TypeName == "llvm_sympart")
628 Type = ELF::SHT_LLVM_SYMPART;
629 else if (TypeName == "llvm_bb_addr_map")
630 Type = ELF::SHT_LLVM_BB_ADDR_MAP;
631 else if (TypeName == "llvm_offloading")
632 Type = ELF::SHT_LLVM_OFFLOADING;
633 else if (TypeName == "llvm_lto")
634 Type = ELF::SHT_LLVM_LTO;
635 else if (TypeName == "llvm_jt_sizes")
636 Type = ELF::SHT_LLVM_JT_SIZES;
637 else if (TypeName == "llvm_cfi_jump_table")
638 Type = ELF::SHT_LLVM_CFI_JUMP_TABLE;
639 else if (TypeName == "llvm_call_graph")
640 Type = ELF::SHT_LLVM_CALL_GRAPH;
641 else if (TypeName.getAsInteger(Radix: 0, Result&: Type))
642 return TokError(Msg: "unknown section type");
643 }
644
645 if (UseLastGroup) {
646 if (auto *Section = static_cast<const MCSectionELF *>(
647 getStreamer().getCurrentSectionOnly()))
648 if (const MCSymbol *Group = Section->getGroup()) {
649 GroupName = Group->getName();
650 IsComdat = Section->isComdat();
651 Flags |= ELF::SHF_GROUP;
652 }
653 }
654
655 MCSectionELF *Section =
656 getContext().getELFSection(Section: SectionName, Type, Flags, EntrySize: Size, Group: GroupName,
657 IsComdat, UniqueID, LinkedToSym);
658 getStreamer().switchSection(Section, Subsection);
659 // Check that flags are used consistently. However, the GNU assembler permits
660 // to leave out in subsequent uses of the same sections; for compatibility,
661 // do likewise.
662 if (!TypeName.empty() && Section->getType() != Type &&
663 !allowSectionTypeMismatch(TT: getContext().getTargetTriple(), SectionName,
664 Type))
665 Error(L: loc, Msg: "changed section type for " + SectionName + ", expected: 0x" +
666 utohexstr(X: Section->getType()));
667 if ((extraFlags || Size || !TypeName.empty()) && Section->getFlags() != Flags)
668 Error(L: loc, Msg: "changed section flags for " + SectionName + ", expected: 0x" +
669 utohexstr(X: Section->getFlags()));
670 if ((extraFlags || Size || !TypeName.empty()) &&
671 Section->getEntrySize() != Size)
672 Error(L: loc, Msg: "changed section entsize for " + SectionName +
673 ", expected: " + Twine(Section->getEntrySize()));
674
675 if (getContext().getGenDwarfForAssembly() &&
676 (Section->getFlags() & ELF::SHF_ALLOC) &&
677 (Section->getFlags() & ELF::SHF_EXECINSTR)) {
678 bool InsertResult = getContext().addGenDwarfSection(Sec: Section);
679 if (InsertResult && getContext().getDwarfVersion() <= 2)
680 Warning(L: loc, Msg: "DWARF2 only supports one section per compilation unit");
681 }
682
683 return false;
684}
685
686bool ELFAsmParser::parseDirectivePrevious(StringRef DirName, SMLoc) {
687 MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
688 if (PreviousSection.first == nullptr)
689 return TokError(Msg: ".previous without corresponding .section");
690 getStreamer().switchSection(Section: PreviousSection.first, Subsec: PreviousSection.second);
691
692 return false;
693}
694
695static MCSymbolAttr MCAttrForString(StringRef Type) {
696 return StringSwitch<MCSymbolAttr>(Type)
697 .Cases(CaseStrings: {"STT_FUNC", "function"}, Value: MCSA_ELF_TypeFunction)
698 .Cases(CaseStrings: {"STT_OBJECT", "object"}, Value: MCSA_ELF_TypeObject)
699 .Cases(CaseStrings: {"STT_TLS", "tls_object"}, Value: MCSA_ELF_TypeTLS)
700 .Cases(CaseStrings: {"STT_COMMON", "common"}, Value: MCSA_ELF_TypeCommon)
701 .Cases(CaseStrings: {"STT_NOTYPE", "notype"}, Value: MCSA_ELF_TypeNoType)
702 .Cases(CaseStrings: {"STT_GNU_IFUNC", "gnu_indirect_function"},
703 Value: MCSA_ELF_TypeIndFunction)
704 .Case(S: "gnu_unique_object", Value: MCSA_ELF_TypeGnuUniqueObject)
705 .Default(Value: MCSA_Invalid);
706}
707
708/// parseDirectiveELFType
709/// ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
710/// ::= .type identifier , #attribute
711/// ::= .type identifier , @attribute
712/// ::= .type identifier , %attribute
713/// ::= .type identifier , "attribute"
714bool ELFAsmParser::parseDirectiveType(StringRef, SMLoc) {
715 MCSymbol *Sym;
716 if (getParser().parseSymbol(Res&: Sym))
717 return TokError(Msg: "expected identifier");
718
719 bool AllowAt = getLexer().getAllowAtInIdentifier();
720 if (!AllowAt &&
721 !getContext().getAsmInfo()->getCommentString().starts_with(Prefix: "@"))
722 getLexer().setAllowAtInIdentifier(true);
723 llvm::scope_exit _([&]() { getLexer().setAllowAtInIdentifier(AllowAt); });
724
725 // NOTE the comma is optional in all cases. It is only documented as being
726 // optional in the first case, however, GAS will silently treat the comma as
727 // optional in all cases. Furthermore, although the documentation states that
728 // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
729 // accepts both the upper case name as well as the lower case aliases.
730 if (getLexer().is(K: AsmToken::Comma))
731 Lex();
732
733 if (getLexer().isNot(K: AsmToken::Identifier) &&
734 getLexer().isNot(K: AsmToken::Hash) &&
735 getLexer().isNot(K: AsmToken::Percent) &&
736 getLexer().isNot(K: AsmToken::String)) {
737 if (!getLexer().getAllowAtInIdentifier())
738 return TokError(Msg: "expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', "
739 "'%<type>' or \"<type>\"");
740 else if (getLexer().isNot(K: AsmToken::At))
741 return TokError(Msg: "expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
742 "'%<type>' or \"<type>\"");
743 }
744
745 if (getLexer().isNot(K: AsmToken::String) &&
746 getLexer().isNot(K: AsmToken::Identifier))
747 Lex();
748
749 SMLoc TypeLoc = getLexer().getLoc();
750
751 StringRef Type;
752 if (getParser().parseIdentifier(Res&: Type))
753 return TokError(Msg: "expected symbol type");
754
755 MCSymbolAttr Attr = MCAttrForString(Type);
756 if (Attr == MCSA_Invalid)
757 return Error(L: TypeLoc, Msg: "unsupported attribute");
758
759 if (getLexer().isNot(K: AsmToken::EndOfStatement))
760 return TokError(Msg: "expected end of directive");
761 Lex();
762
763 getStreamer().emitSymbolAttribute(Symbol: Sym, Attribute: Attr);
764
765 return false;
766}
767
768/// parseDirectiveIdent
769/// ::= .ident string
770bool ELFAsmParser::parseDirectiveIdent(StringRef, SMLoc) {
771 if (getLexer().isNot(K: AsmToken::String))
772 return TokError(Msg: "expected string");
773
774 StringRef Data = getTok().getIdentifier();
775
776 Lex();
777
778 if (getLexer().isNot(K: AsmToken::EndOfStatement))
779 return TokError(Msg: "expected end of directive");
780 Lex();
781
782 getStreamer().emitIdent(IdentString: Data);
783 return false;
784}
785
786/// parseDirectiveSymver
787/// ::= .symver foo, bar2@zed
788bool ELFAsmParser::parseDirectiveSymver(StringRef, SMLoc) {
789 MCSymbol *OriginalSym;
790 StringRef Name, Action;
791 if (getParser().parseSymbol(Res&: OriginalSym))
792 return TokError(Msg: "expected identifier");
793
794 if (getLexer().isNot(K: AsmToken::Comma))
795 return TokError(Msg: "expected a comma");
796
797 // ARM assembly uses @ for a comment...
798 // except when parsing the second parameter of the .symver directive.
799 // Force the next symbol to allow @ in the identifier, which is
800 // required for this directive and then reset it to its initial state.
801 const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
802 getLexer().setAllowAtInIdentifier(true);
803 Lex();
804 getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
805
806 if (getParser().parseIdentifier(Res&: Name))
807 return TokError(Msg: "expected identifier");
808
809 if (!Name.contains(C: '@'))
810 return TokError(Msg: "expected a '@' in the name");
811 bool KeepOriginalSym = !Name.contains(Other: "@@@");
812 if (parseOptionalToken(T: AsmToken::Comma)) {
813 if (getParser().parseIdentifier(Res&: Action) || Action != "remove")
814 return TokError(Msg: "expected 'remove'");
815 KeepOriginalSym = false;
816 }
817 (void)parseOptionalToken(T: AsmToken::EndOfStatement);
818
819 getStreamer().emitELFSymverDirective(OriginalSym, Name, KeepOriginalSym);
820 return false;
821}
822
823/// parseDirectiveVersion
824/// ::= .version string
825bool ELFAsmParser::parseDirectiveVersion(StringRef, SMLoc) {
826 if (getLexer().isNot(K: AsmToken::String))
827 return TokError(Msg: "expected string");
828
829 StringRef Data = getTok().getIdentifier();
830
831 Lex();
832
833 MCSection *Note = getContext().getELFSection(Section: ".note", Type: ELF::SHT_NOTE, Flags: 0);
834
835 getStreamer().pushSection();
836 getStreamer().switchSection(Section: Note);
837 getStreamer().emitInt32(Value: Data.size() + 1); // namesz
838 getStreamer().emitInt32(Value: 0); // descsz = 0 (no description).
839 getStreamer().emitInt32(Value: 1); // type = NT_VERSION
840 getStreamer().emitBytes(Data); // name
841 getStreamer().emitInt8(Value: 0); // NUL
842 getStreamer().emitValueToAlignment(Alignment: Align(4));
843 getStreamer().popSection();
844 return false;
845}
846
847/// parseDirectiveWeakref
848/// ::= .weakref foo, bar
849bool ELFAsmParser::parseDirectiveWeakref(StringRef, SMLoc) {
850 // FIXME: Share code with the other alias building directives.
851
852 MCSymbol *Alias;
853 if (getParser().parseSymbol(Res&: Alias))
854 return TokError(Msg: "expected identifier");
855
856 if (getLexer().isNot(K: AsmToken::Comma))
857 return TokError(Msg: "expected a comma");
858
859 Lex();
860
861 MCSymbol *Sym;
862 if (getParser().parseSymbol(Res&: Sym))
863 return TokError(Msg: "expected identifier");
864
865 getStreamer().emitWeakReference(Alias, Symbol: Sym);
866 return false;
867}
868
869bool ELFAsmParser::parseDirectiveSubsection(StringRef, SMLoc) {
870 const MCExpr *Subsection = MCConstantExpr::create(Value: 0, Ctx&: getContext());
871 if (getLexer().isNot(K: AsmToken::EndOfStatement)) {
872 if (getParser().parseExpression(Res&: Subsection))
873 return true;
874 }
875
876 if (getLexer().isNot(K: AsmToken::EndOfStatement))
877 return TokError(Msg: "expected end of directive");
878
879 Lex();
880
881 return getStreamer().switchSection(Section: getStreamer().getCurrentSectionOnly(),
882 Subsection);
883}
884
885bool ELFAsmParser::parseDirectiveCGProfile(StringRef S, SMLoc Loc) {
886 return MCAsmParserExtension::parseDirectiveCGProfile(S, Loc);
887}
888
889MCAsmParserExtension *llvm::createELFAsmParser() { return new ELFAsmParser; }
890