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llvm-mirror/lib/MC/MCParser/ELFAsmParser.cpp
Roman Divacky a450b8b2c8 Add support for gnu_indirect_function. 
llvm-svn: 146377
2011-12-12 17:34:04 +00:00

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//===- ELFAsmParser.cpp - ELF Assembly Parser -----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCParser/MCAsmParserExtension.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Support/ELF.h"
using namespace llvm;
namespace {
class ELFAsmParser : public MCAsmParserExtension {
template<bool (ELFAsmParser::*Handler)(StringRef, SMLoc)>
void AddDirectiveHandler(StringRef Directive) {
getParser().AddDirectiveHandler(this, Directive,
HandleDirective<ELFAsmParser, Handler>);
}
bool ParseSectionSwitch(StringRef Section, unsigned Type,
unsigned Flags, SectionKind Kind);
bool SeenIdent;
public:
ELFAsmParser() : SeenIdent(false) {
BracketExpressionsSupported = true;
}
virtual void Initialize(MCAsmParser &Parser) {
// Call the base implementation.
this->MCAsmParserExtension::Initialize(Parser);
AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
AddDirectiveHandler<
&ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel");
AddDirectiveHandler<
&ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro");
AddDirectiveHandler<
&ELFAsmParser::ParseSectionDirectiveDataRelRoLocal>(".data.rel.ro.local");
AddDirectiveHandler<
&ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
AddDirectiveHandler<
&ELFAsmParser::ParseDirectivePushSection>(".pushsection");
AddDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
AddDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local");
AddDirectiveHandler<
&ELFAsmParser::ParseDirectiveSymbolAttribute>(".protected");
AddDirectiveHandler<
&ELFAsmParser::ParseDirectiveSymbolAttribute>(".internal");
AddDirectiveHandler<
&ELFAsmParser::ParseDirectiveSymbolAttribute>(".hidden");
}
// FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
// the best way for us to get access to it?
bool ParseSectionDirectiveData(StringRef, SMLoc) {
return ParseSectionSwitch(".data", ELF::SHT_PROGBITS,
ELF::SHF_WRITE |ELF::SHF_ALLOC,
SectionKind::getDataRel());
}
bool ParseSectionDirectiveText(StringRef, SMLoc) {
return ParseSectionSwitch(".text", ELF::SHT_PROGBITS,
ELF::SHF_EXECINSTR |
ELF::SHF_ALLOC, SectionKind::getText());
}
bool ParseSectionDirectiveBSS(StringRef, SMLoc) {
return ParseSectionSwitch(".bss", ELF::SHT_NOBITS,
ELF::SHF_WRITE |
ELF::SHF_ALLOC, SectionKind::getBSS());
}
bool ParseSectionDirectiveRoData(StringRef, SMLoc) {
return ParseSectionSwitch(".rodata", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC,
SectionKind::getReadOnly());
}
bool ParseSectionDirectiveTData(StringRef, SMLoc) {
return ParseSectionSwitch(".tdata", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC |
ELF::SHF_TLS | ELF::SHF_WRITE,
SectionKind::getThreadData());
}
bool ParseSectionDirectiveTBSS(StringRef, SMLoc) {
return ParseSectionSwitch(".tbss", ELF::SHT_NOBITS,
ELF::SHF_ALLOC |
ELF::SHF_TLS | ELF::SHF_WRITE,
SectionKind::getThreadBSS());
}
bool ParseSectionDirectiveDataRel(StringRef, SMLoc) {
return ParseSectionSwitch(".data.rel", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC |
ELF::SHF_WRITE,
SectionKind::getDataRel());
}
bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) {
return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC |
ELF::SHF_WRITE,
SectionKind::getReadOnlyWithRel());
}
bool ParseSectionDirectiveDataRelRoLocal(StringRef, SMLoc) {
return ParseSectionSwitch(".data.rel.ro.local", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC |
ELF::SHF_WRITE,
SectionKind::getReadOnlyWithRelLocal());
}
bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) {
return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC |
ELF::SHF_WRITE,
SectionKind::getDataRel());
}
bool ParseDirectivePushSection(StringRef, SMLoc);
bool ParseDirectivePopSection(StringRef, SMLoc);
bool ParseDirectiveSection(StringRef, SMLoc);
bool ParseDirectiveSize(StringRef, SMLoc);
bool ParseDirectivePrevious(StringRef, SMLoc);
bool ParseDirectiveType(StringRef, SMLoc);
bool ParseDirectiveIdent(StringRef, SMLoc);
bool ParseDirectiveSymver(StringRef, SMLoc);
bool ParseDirectiveWeakref(StringRef, SMLoc);
bool ParseDirectiveSymbolAttribute(StringRef, SMLoc);
private:
bool ParseSectionName(StringRef &SectionName);
};
}
/// ParseDirectiveSymbolAttribute
/// ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ]
bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
.Case(".weak", MCSA_Weak)
.Case(".local", MCSA_Local)
.Case(".hidden", MCSA_Hidden)
.Case(".internal", MCSA_Internal)
.Case(".protected", MCSA_Protected)
.Default(MCSA_Invalid);
assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
if (getLexer().isNot(AsmToken::EndOfStatement)) {
for (;;) {
StringRef Name;
if (getParser().ParseIdentifier(Name))
return TokError("expected identifier in directive");
MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
getStreamer().EmitSymbolAttribute(Sym, Attr);
if (getLexer().is(AsmToken::EndOfStatement))
break;
if (getLexer().isNot(AsmToken::Comma))
return TokError("unexpected token in directive");
Lex();
}
}
Lex();
return false;
}
bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
unsigned Flags, SectionKind Kind) {
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in section switching directive");
Lex();
getStreamer().SwitchSection(getContext().getELFSection(
Section, Type, Flags, Kind));
return false;
}
bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
StringRef Name;
if (getParser().ParseIdentifier(Name))
return TokError("expected identifier in directive");
MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);;
if (getLexer().isNot(AsmToken::Comma))
return TokError("unexpected token in directive");
Lex();
const MCExpr *Expr;
if (getParser().ParseExpression(Expr))
return true;
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in directive");
getStreamer().EmitELFSize(Sym, Expr);
return false;
}
bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
// A section name can contain -, so we cannot just use
// ParseIdentifier.
SMLoc FirstLoc = getLexer().getLoc();
unsigned Size = 0;
if (getLexer().is(AsmToken::String)) {
SectionName = getTok().getIdentifier();
Lex();
return false;
}
for (;;) {
StringRef Tmp;
unsigned CurSize;
SMLoc PrevLoc = getLexer().getLoc();
if (getLexer().is(AsmToken::Minus)) {
CurSize = 1;
Lex(); // Consume the "-".
} else if (getLexer().is(AsmToken::String)) {
CurSize = getTok().getIdentifier().size() + 2;
Lex();
} else if (getLexer().is(AsmToken::Identifier)) {
CurSize = getTok().getIdentifier().size();
Lex();
} else {
break;
}
Size += CurSize;
SectionName = StringRef(FirstLoc.getPointer(), Size);
// Make sure the following token is adjacent.
if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
break;
}
if (Size == 0)
return true;
return false;
}
static SectionKind computeSectionKind(unsigned Flags) {
if (Flags & ELF::SHF_EXECINSTR)
return SectionKind::getText();
if (Flags & ELF::SHF_TLS)
return SectionKind::getThreadData();
return SectionKind::getDataRel();
}
static int parseSectionFlags(StringRef flagsStr) {
int flags = 0;
for (unsigned i = 0; i < flagsStr.size(); i++) {
switch (flagsStr[i]) {
case 'a':
flags |= ELF::SHF_ALLOC;
break;
case 'x':
flags |= ELF::SHF_EXECINSTR;
break;
case 'w':
flags |= ELF::SHF_WRITE;
break;
case 'M':
flags |= ELF::SHF_MERGE;
break;
case 'S':
flags |= ELF::SHF_STRINGS;
break;
case 'T':
flags |= ELF::SHF_TLS;
break;
case 'c':
flags |= ELF::XCORE_SHF_CP_SECTION;
break;
case 'd':
flags |= ELF::XCORE_SHF_DP_SECTION;
break;
case 'G':
flags |= ELF::SHF_GROUP;
break;
default:
return -1;
}
}
return flags;
}
bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
getStreamer().PushSection();
if (ParseDirectiveSection(s, loc)) {
getStreamer().PopSection();
return true;
}
return false;
}
bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
if (!getStreamer().PopSection())
return TokError(".popsection without corresponding .pushsection");
return false;
}
// FIXME: This is a work in progress.
bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
StringRef SectionName;
if (ParseSectionName(SectionName))
return TokError("expected identifier in directive");
StringRef TypeName;
int64_t Size = 0;
StringRef GroupName;
unsigned Flags = 0;
// Set the defaults first.
if (SectionName == ".fini" || SectionName == ".init" ||
SectionName == ".rodata")
Flags |= ELF::SHF_ALLOC;
if (SectionName == ".fini" || SectionName == ".init")
Flags |= ELF::SHF_EXECINSTR;
if (getLexer().is(AsmToken::Comma)) {
Lex();
if (getLexer().isNot(AsmToken::String))
return TokError("expected string in directive");
StringRef FlagsStr = getTok().getStringContents();
Lex();
int extraFlags = parseSectionFlags(FlagsStr);
if (extraFlags < 0)
return TokError("unknown flag");
Flags |= extraFlags;
bool Mergeable = Flags & ELF::SHF_MERGE;
bool Group = Flags & ELF::SHF_GROUP;
if (getLexer().isNot(AsmToken::Comma)) {
if (Mergeable)
return TokError("Mergeable section must specify the type");
if (Group)
return TokError("Group section must specify the type");
} else {
Lex();
if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
return TokError("expected '@' or '%' before type");
Lex();
if (getParser().ParseIdentifier(TypeName))
return TokError("expected identifier in directive");
if (Mergeable) {
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected the entry size");
Lex();
if (getParser().ParseAbsoluteExpression(Size))
return true;
if (Size <= 0)
return TokError("entry size must be positive");
}
if (Group) {
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected group name");
Lex();
if (getParser().ParseIdentifier(GroupName))
return true;
if (getLexer().is(AsmToken::Comma)) {
Lex();
StringRef Linkage;
if (getParser().ParseIdentifier(Linkage))
return true;
if (Linkage != "comdat")
return TokError("Linkage must be 'comdat'");
}
}
}
}
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in directive");
unsigned Type = ELF::SHT_PROGBITS;
if (!TypeName.empty()) {
if (TypeName == "init_array")
Type = ELF::SHT_INIT_ARRAY;
else if (TypeName == "fini_array")
Type = ELF::SHT_FINI_ARRAY;
else if (TypeName == "preinit_array")
Type = ELF::SHT_PREINIT_ARRAY;
else if (TypeName == "nobits")
Type = ELF::SHT_NOBITS;
else if (TypeName == "progbits")
Type = ELF::SHT_PROGBITS;
else if (TypeName == "note")
Type = ELF::SHT_NOTE;
else if (TypeName == "unwind")
Type = ELF::SHT_X86_64_UNWIND;
else
return TokError("unknown section type");
}
SectionKind Kind = computeSectionKind(Flags);
getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
Flags, Kind, Size,
GroupName));
return false;
}
bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
const MCSection *PreviousSection = getStreamer().getPreviousSection();
if (PreviousSection == NULL)
return TokError(".previous without corresponding .section");
getStreamer().SwitchSection(PreviousSection);
return false;
}
/// ParseDirectiveELFType
/// ::= .type identifier , @attribute
bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
StringRef Name;
if (getParser().ParseIdentifier(Name))
return TokError("expected identifier in directive");
// Handle the identifier as the key symbol.
MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
if (getLexer().isNot(AsmToken::Comma))
return TokError("unexpected token in '.type' directive");
Lex();
if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
return TokError("expected '@' or '%' before type");
Lex();
StringRef Type;
SMLoc TypeLoc;
TypeLoc = getLexer().getLoc();
if (getParser().ParseIdentifier(Type))
return TokError("expected symbol type in directive");
MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Type)
.Case("function", MCSA_ELF_TypeFunction)
.Case("object", MCSA_ELF_TypeObject)
.Case("tls_object", MCSA_ELF_TypeTLS)
.Case("common", MCSA_ELF_TypeCommon)
.Case("notype", MCSA_ELF_TypeNoType)
.Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
.Case("gnu_indirect_function", MCSA_ELF_TypeIndFunction)
.Default(MCSA_Invalid);
if (Attr == MCSA_Invalid)
return Error(TypeLoc, "unsupported attribute in '.type' directive");
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in '.type' directive");
Lex();
getStreamer().EmitSymbolAttribute(Sym, Attr);
return false;
}
/// ParseDirectiveIdent
/// ::= .ident string
bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
if (getLexer().isNot(AsmToken::String))
return TokError("unexpected token in '.ident' directive");
StringRef Data = getTok().getIdentifier();
Lex();
const MCSection *Comment =
getContext().getELFSection(".comment", ELF::SHT_PROGBITS,
ELF::SHF_MERGE |
ELF::SHF_STRINGS,
SectionKind::getReadOnly(),
1, "");
getStreamer().PushSection();
getStreamer().SwitchSection(Comment);
if (!SeenIdent) {
getStreamer().EmitIntValue(0, 1);
SeenIdent = true;
}
getStreamer().EmitBytes(Data, 0);
getStreamer().EmitIntValue(0, 1);
getStreamer().PopSection();
return false;
}
/// ParseDirectiveSymver
/// ::= .symver foo, bar2@zed
bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
StringRef Name;
if (getParser().ParseIdentifier(Name))
return TokError("expected identifier in directive");
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected a comma");
Lex();
StringRef AliasName;
if (getParser().ParseIdentifier(AliasName))
return TokError("expected identifier in directive");
if (AliasName.find('@') == StringRef::npos)
return TokError("expected a '@' in the name");
MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
const MCExpr *Value = MCSymbolRefExpr::Create(Sym, getContext());
getStreamer().EmitAssignment(Alias, Value);
return false;
}
/// ParseDirectiveWeakref
/// ::= .weakref foo, bar
bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
// FIXME: Share code with the other alias building directives.
StringRef AliasName;
if (getParser().ParseIdentifier(AliasName))
return TokError("expected identifier in directive");
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected a comma");
Lex();
StringRef Name;
if (getParser().ParseIdentifier(Name))
return TokError("expected identifier in directive");
MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
getStreamer().EmitWeakReference(Alias, Sym);
return false;
}
namespace llvm {
MCAsmParserExtension *createELFAsmParser() {
return new ELFAsmParser;
}
}
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