1 //===- ELFAsmParser.cpp - ELF Assembly Parser -----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCParser/MCAsmParserExtension.h"
11 #include "llvm/ADT/StringSwitch.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/MC/MCAsmInfo.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCParser/MCAsmLexer.h"
17 #include "llvm/MC/MCSectionELF.h"
18 #include "llvm/MC/MCStreamer.h"
19 #include "llvm/Support/ELF.h"
24 class ELFAsmParser : public MCAsmParserExtension {
25 template<bool (ELFAsmParser::*Handler)(StringRef, SMLoc)>
26 void AddDirectiveHandler(StringRef Directive) {
27 getParser().AddDirectiveHandler(this, Directive,
28 HandleDirective<ELFAsmParser, Handler>);
31 bool ParseSectionSwitch(StringRef Section, unsigned Type,
32 unsigned Flags, SectionKind Kind);
36 ELFAsmParser() : SeenIdent(false) {
37 BracketExpressionsSupported = true;
40 virtual void Initialize(MCAsmParser &Parser) {
41 // Call the base implementation.
42 this->MCAsmParserExtension::Initialize(Parser);
44 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
45 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
46 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
47 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
48 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
49 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
50 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel");
51 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro");
52 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRelRoLocal>(".data.rel.ro.local");
53 AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
54 AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
55 AddDirectiveHandler<&ELFAsmParser::ParseDirectivePushSection>(".pushsection");
56 AddDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
57 AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
58 AddDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
59 AddDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
60 AddDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
61 AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
62 AddDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
65 // FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
66 // the best way for us to get access to it?
67 bool ParseSectionDirectiveData(StringRef, SMLoc) {
68 return ParseSectionSwitch(".data", ELF::SHT_PROGBITS,
69 ELF::SHF_WRITE |ELF::SHF_ALLOC,
70 SectionKind::getDataRel());
72 bool ParseSectionDirectiveText(StringRef, SMLoc) {
73 return ParseSectionSwitch(".text", ELF::SHT_PROGBITS,
75 ELF::SHF_ALLOC, SectionKind::getText());
77 bool ParseSectionDirectiveBSS(StringRef, SMLoc) {
78 return ParseSectionSwitch(".bss", ELF::SHT_NOBITS,
80 ELF::SHF_ALLOC, SectionKind::getBSS());
82 bool ParseSectionDirectiveRoData(StringRef, SMLoc) {
83 return ParseSectionSwitch(".rodata", ELF::SHT_PROGBITS,
85 SectionKind::getReadOnly());
87 bool ParseSectionDirectiveTData(StringRef, SMLoc) {
88 return ParseSectionSwitch(".tdata", ELF::SHT_PROGBITS,
90 ELF::SHF_TLS | ELF::SHF_WRITE,
91 SectionKind::getThreadData());
93 bool ParseSectionDirectiveTBSS(StringRef, SMLoc) {
94 return ParseSectionSwitch(".tbss", ELF::SHT_NOBITS,
96 ELF::SHF_TLS | ELF::SHF_WRITE,
97 SectionKind::getThreadBSS());
99 bool ParseSectionDirectiveDataRel(StringRef, SMLoc) {
100 return ParseSectionSwitch(".data.rel", ELF::SHT_PROGBITS,
103 SectionKind::getDataRel());
105 bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) {
106 return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS,
109 SectionKind::getReadOnlyWithRel());
111 bool ParseSectionDirectiveDataRelRoLocal(StringRef, SMLoc) {
112 return ParseSectionSwitch(".data.rel.ro.local", ELF::SHT_PROGBITS,
115 SectionKind::getReadOnlyWithRelLocal());
117 bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) {
118 return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS,
121 SectionKind::getDataRel());
123 bool ParseDirectivePushSection(StringRef, SMLoc);
124 bool ParseDirectivePopSection(StringRef, SMLoc);
125 bool ParseDirectiveSection(StringRef, SMLoc);
126 bool ParseDirectiveSize(StringRef, SMLoc);
127 bool ParseDirectivePrevious(StringRef, SMLoc);
128 bool ParseDirectiveType(StringRef, SMLoc);
129 bool ParseDirectiveIdent(StringRef, SMLoc);
130 bool ParseDirectiveSymver(StringRef, SMLoc);
131 bool ParseDirectiveWeakref(StringRef, SMLoc);
134 bool ParseSectionName(StringRef &SectionName);
139 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
140 unsigned Flags, SectionKind Kind) {
141 if (getLexer().isNot(AsmToken::EndOfStatement))
142 return TokError("unexpected token in section switching directive");
145 getStreamer().SwitchSection(getContext().getELFSection(
146 Section, Type, Flags, Kind));
151 bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
153 if (getParser().ParseIdentifier(Name))
154 return TokError("expected identifier in directive");
155 MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);;
157 if (getLexer().isNot(AsmToken::Comma))
158 return TokError("unexpected token in directive");
162 if (getParser().ParseExpression(Expr))
165 if (getLexer().isNot(AsmToken::EndOfStatement))
166 return TokError("unexpected token in directive");
168 getStreamer().EmitELFSize(Sym, Expr);
172 bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
173 // A section name can contain -, so we cannot just use
175 SMLoc FirstLoc = getLexer().getLoc();
178 if (getLexer().is(AsmToken::String)) {
179 SectionName = getTok().getIdentifier();
188 SMLoc PrevLoc = getLexer().getLoc();
189 if (getLexer().is(AsmToken::Minus)) {
191 Lex(); // Consume the "-".
192 } else if (getLexer().is(AsmToken::String)) {
193 CurSize = getTok().getIdentifier().size() + 2;
195 } else if (getLexer().is(AsmToken::Identifier)) {
196 CurSize = getTok().getIdentifier().size();
203 SectionName = StringRef(FirstLoc.getPointer(), Size);
205 // Make sure the following token is adjacent.
206 if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
215 static SectionKind computeSectionKind(unsigned Flags) {
216 if (Flags & ELF::SHF_EXECINSTR)
217 return SectionKind::getText();
218 if (Flags & ELF::SHF_TLS)
219 return SectionKind::getThreadData();
220 return SectionKind::getDataRel();
223 static int parseSectionFlags(StringRef flagsStr) {
226 for (unsigned i = 0; i < flagsStr.size(); i++) {
227 switch (flagsStr[i]) {
229 flags |= ELF::SHF_ALLOC;
232 flags |= ELF::SHF_EXECINSTR;
235 flags |= ELF::SHF_WRITE;
238 flags |= ELF::SHF_MERGE;
241 flags |= ELF::SHF_STRINGS;
244 flags |= ELF::SHF_TLS;
247 flags |= ELF::XCORE_SHF_CP_SECTION;
250 flags |= ELF::XCORE_SHF_DP_SECTION;
253 flags |= ELF::SHF_GROUP;
263 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
264 getStreamer().PushSection();
266 if (ParseDirectiveSection(s, loc)) {
267 getStreamer().PopSection();
274 bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
275 if (!getStreamer().PopSection())
276 return TokError(".popsection without corresponding .pushsection");
280 // FIXME: This is a work in progress.
281 bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
282 StringRef SectionName;
284 if (ParseSectionName(SectionName))
285 return TokError("expected identifier in directive");
292 // Set the defaults first.
293 if (SectionName == ".fini" || SectionName == ".init" ||
294 SectionName == ".rodata")
295 Flags |= ELF::SHF_ALLOC;
296 if (SectionName == ".fini" || SectionName == ".init")
297 Flags |= ELF::SHF_EXECINSTR;
299 if (getLexer().is(AsmToken::Comma)) {
302 if (getLexer().isNot(AsmToken::String))
303 return TokError("expected string in directive");
305 StringRef FlagsStr = getTok().getStringContents();
308 int extraFlags = parseSectionFlags(FlagsStr);
310 return TokError("unknown flag");
313 bool Mergeable = Flags & ELF::SHF_MERGE;
314 bool Group = Flags & ELF::SHF_GROUP;
316 if (getLexer().isNot(AsmToken::Comma)) {
318 return TokError("Mergeable section must specify the type");
320 return TokError("Group section must specify the type");
323 if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
324 return TokError("expected '@' or '%' before type");
327 if (getParser().ParseIdentifier(TypeName))
328 return TokError("expected identifier in directive");
331 if (getLexer().isNot(AsmToken::Comma))
332 return TokError("expected the entry size");
334 if (getParser().ParseAbsoluteExpression(Size))
337 return TokError("entry size must be positive");
341 if (getLexer().isNot(AsmToken::Comma))
342 return TokError("expected group name");
344 if (getParser().ParseIdentifier(GroupName))
346 if (getLexer().is(AsmToken::Comma)) {
349 if (getParser().ParseIdentifier(Linkage))
351 if (Linkage != "comdat")
352 return TokError("Linkage must be 'comdat'");
358 if (getLexer().isNot(AsmToken::EndOfStatement))
359 return TokError("unexpected token in directive");
361 unsigned Type = ELF::SHT_PROGBITS;
363 if (!TypeName.empty()) {
364 if (TypeName == "init_array")
365 Type = ELF::SHT_INIT_ARRAY;
366 else if (TypeName == "fini_array")
367 Type = ELF::SHT_FINI_ARRAY;
368 else if (TypeName == "preinit_array")
369 Type = ELF::SHT_PREINIT_ARRAY;
370 else if (TypeName == "nobits")
371 Type = ELF::SHT_NOBITS;
372 else if (TypeName == "progbits")
373 Type = ELF::SHT_PROGBITS;
374 else if (TypeName == "note")
375 Type = ELF::SHT_NOTE;
376 else if (TypeName == "unwind")
377 Type = ELF::SHT_X86_64_UNWIND;
379 return TokError("unknown section type");
382 SectionKind Kind = computeSectionKind(Flags);
383 getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
389 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
390 const MCSection *PreviousSection = getStreamer().getPreviousSection();
391 if (PreviousSection == NULL)
392 return TokError(".previous without corresponding .section");
393 getStreamer().SwitchSection(PreviousSection);
398 /// ParseDirectiveELFType
399 /// ::= .type identifier , @attribute
400 bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
402 if (getParser().ParseIdentifier(Name))
403 return TokError("expected identifier in directive");
405 // Handle the identifier as the key symbol.
406 MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
408 if (getLexer().isNot(AsmToken::Comma))
409 return TokError("unexpected token in '.type' directive");
412 if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
413 return TokError("expected '@' or '%' before type");
419 TypeLoc = getLexer().getLoc();
420 if (getParser().ParseIdentifier(Type))
421 return TokError("expected symbol type in directive");
423 MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Type)
424 .Case("function", MCSA_ELF_TypeFunction)
425 .Case("object", MCSA_ELF_TypeObject)
426 .Case("tls_object", MCSA_ELF_TypeTLS)
427 .Case("common", MCSA_ELF_TypeCommon)
428 .Case("notype", MCSA_ELF_TypeNoType)
429 .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
430 .Default(MCSA_Invalid);
432 if (Attr == MCSA_Invalid)
433 return Error(TypeLoc, "unsupported attribute in '.type' directive");
435 if (getLexer().isNot(AsmToken::EndOfStatement))
436 return TokError("unexpected token in '.type' directive");
440 getStreamer().EmitSymbolAttribute(Sym, Attr);
445 /// ParseDirectiveIdent
446 /// ::= .ident string
447 bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
448 if (getLexer().isNot(AsmToken::String))
449 return TokError("unexpected token in '.ident' directive");
451 StringRef Data = getTok().getIdentifier();
455 const MCSection *Comment =
456 getContext().getELFSection(".comment", ELF::SHT_PROGBITS,
459 SectionKind::getReadOnly(),
462 getStreamer().PushSection();
463 getStreamer().SwitchSection(Comment);
465 getStreamer().EmitIntValue(0, 1);
468 getStreamer().EmitBytes(Data, 0);
469 getStreamer().EmitIntValue(0, 1);
470 getStreamer().PopSection();
474 /// ParseDirectiveSymver
475 /// ::= .symver foo, bar2@zed
476 bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
478 if (getParser().ParseIdentifier(Name))
479 return TokError("expected identifier in directive");
481 if (getLexer().isNot(AsmToken::Comma))
482 return TokError("expected a comma");
487 if (getParser().ParseIdentifier(AliasName))
488 return TokError("expected identifier in directive");
490 if (AliasName.find('@') == StringRef::npos)
491 return TokError("expected a '@' in the name");
493 MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
494 MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
495 const MCExpr *Value = MCSymbolRefExpr::Create(Sym, getContext());
497 getStreamer().EmitAssignment(Alias, Value);
501 /// ParseDirectiveWeakref
502 /// ::= .weakref foo, bar
503 bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
504 // FIXME: Share code with the other alias building directives.
507 if (getParser().ParseIdentifier(AliasName))
508 return TokError("expected identifier in directive");
510 if (getLexer().isNot(AsmToken::Comma))
511 return TokError("expected a comma");
516 if (getParser().ParseIdentifier(Name))
517 return TokError("expected identifier in directive");
519 MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
521 MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
523 getStreamer().EmitWeakReference(Alias, Sym);
529 MCAsmParserExtension *createELFAsmParser() {
530 return new ELFAsmParser;