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llvm-6502/lib/MC/MCParser/ELFAsmParser.cpp
Oliver Stannard 98ef3474ef Downgrade DWARF2 section limit error to a warning 
We currently emit an error when trying to assemble a file with more
than one section using DWARF2 debug info. This should be a warning
instead, as the resulting file will still be usable, but with a
degraded debug illusion.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218241 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-22 10:45:16 +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/MC/MCSymbol.h"
#include "llvm/Support/ELF.h"
using namespace llvm;
namespace {
class ELFAsmParser : public MCAsmParserExtension {
template<bool (ELFAsmParser::*HandlerMethod)(StringRef, SMLoc)>
void addDirectiveHandler(StringRef Directive) {
MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair(
this, HandleDirective<ELFAsmParser, HandlerMethod>);
getParser().addDirectiveHandler(Directive, Handler);
}
bool ParseSectionSwitch(StringRef Section, unsigned Type, unsigned Flags,
SectionKind Kind);
public:
ELFAsmParser() { BracketExpressionsSupported = true; }
void Initialize(MCAsmParser &Parser) override {
// 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::ParseDirectiveVersion>(".version");
addDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local");
addDirectiveHandler<
&ELFAsmParser::ParseDirectiveSymbolAttribute>(".protected");
addDirectiveHandler<
&ELFAsmParser::ParseDirectiveSymbolAttribute>(".internal");
addDirectiveHandler<
&ELFAsmParser::ParseDirectiveSymbolAttribute>(".hidden");
addDirectiveHandler<&ELFAsmParser::ParseDirectiveSubsection>(".subsection");
}
// 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 ParseDirectiveVersion(StringRef, SMLoc);
bool ParseDirectiveWeakref(StringRef, SMLoc);
bool ParseDirectiveSymbolAttribute(StringRef, SMLoc);
bool ParseDirectiveSubsection(StringRef, SMLoc);
private:
bool ParseSectionName(StringRef &SectionName);
bool ParseSectionArguments(bool IsPush, SMLoc loc);
unsigned parseSunStyleSectionFlags();
};
}
/// 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) {
const MCExpr *Subsection = nullptr;
if (getLexer().isNot(AsmToken::EndOfStatement)) {
if (getParser().parseExpression(Subsection))
return true;
}
getStreamer().SwitchSection(getContext().getELFSection(
Section, Type, Flags, Kind),
Subsection);
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 (;;) {
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, unsigned ElemSize) {
if (Flags & ELF::SHF_EXECINSTR)
return SectionKind::getText();
if (Flags & ELF::SHF_TLS)
return SectionKind::getThreadData();
if (Flags & ELF::SHF_MERGE) {
if (Flags & ELF::SHF_STRINGS) {
switch (ElemSize) {
default:
break;
case 1:
return SectionKind::getMergeable1ByteCString();
case 2:
return SectionKind::getMergeable2ByteCString();
case 4:
return SectionKind::getMergeable4ByteCString();
}
} else {
switch (ElemSize) {
default:
break;
case 4:
return SectionKind::getMergeableConst4();
case 8:
return SectionKind::getMergeableConst8();
case 16:
return SectionKind::getMergeableConst16();
}
}
}
return SectionKind::getDataRel();
}
static unsigned parseSectionFlags(StringRef flagsStr, bool *UseLastGroup) {
unsigned flags = 0;
for (unsigned i = 0; i < flagsStr.size(); i++) {
switch (flagsStr[i]) {
case 'a':
flags |= ELF::SHF_ALLOC;
break;
case 'e':
flags |= ELF::SHF_EXCLUDE;
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;
case '?':
*UseLastGroup = true;
break;
default:
return -1U;
}
}
return flags;
}
unsigned ELFAsmParser::parseSunStyleSectionFlags() {
unsigned flags = 0;
while (getLexer().is(AsmToken::Hash)) {
Lex(); // Eat the #.
if (!getLexer().is(AsmToken::Identifier))
return -1U;
StringRef flagId = getTok().getIdentifier();
if (flagId == "alloc")
flags |= ELF::SHF_ALLOC;
else if (flagId == "execinstr")
flags |= ELF::SHF_EXECINSTR;
else if (flagId == "write")
flags |= ELF::SHF_WRITE;
else if (flagId == "tls")
flags |= ELF::SHF_TLS;
else
return -1U;
Lex(); // Eat the flag.
if (!getLexer().is(AsmToken::Comma))
break;
Lex(); // Eat the comma.
}
return flags;
}
bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
getStreamer().PushSection();
if (ParseSectionArguments(/*IsPush=*/true, 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 loc) {
return ParseSectionArguments(/*IsPush=*/false, loc);
}
bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
StringRef SectionName;
if (ParseSectionName(SectionName))
return TokError("expected identifier in directive");
StringRef TypeName;
int64_t Size = 0;
StringRef GroupName;
unsigned Flags = 0;
const MCExpr *Subsection = nullptr;
bool UseLastGroup = false;
// 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 (IsPush && getLexer().isNot(AsmToken::String)) {
if (getParser().parseExpression(Subsection))
return true;
if (getLexer().isNot(AsmToken::Comma))
goto EndStmt;
Lex();
}
unsigned extraFlags;
if (getLexer().isNot(AsmToken::String)) {
if (!getContext().getAsmInfo()->usesSunStyleELFSectionSwitchSyntax()
|| getLexer().isNot(AsmToken::Hash))
return TokError("expected string in directive");
extraFlags = parseSunStyleSectionFlags();
} else {
StringRef FlagsStr = getTok().getStringContents();
Lex();
extraFlags = parseSectionFlags(FlagsStr, &UseLastGroup);
}
if (extraFlags == -1U)
return TokError("unknown flag");
Flags |= extraFlags;
bool Mergeable = Flags & ELF::SHF_MERGE;
bool Group = Flags & ELF::SHF_GROUP;
if (Group && UseLastGroup)
return TokError("Section cannot specifiy a group name while also acting "
"as a member of the last 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().is(AsmToken::At) || getLexer().is(AsmToken::Percent) ||
getLexer().is(AsmToken::String)) {
if (!getLexer().is(AsmToken::String))
Lex();
} else
return TokError("expected '@<type>', '%<type>' or \"<type>\"");
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'");
}
}
}
}
EndStmt:
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in directive");
unsigned Type = ELF::SHT_PROGBITS;
if (TypeName.empty()) {
if (SectionName.startswith(".note"))
Type = ELF::SHT_NOTE;
else if (SectionName == ".init_array")
Type = ELF::SHT_INIT_ARRAY;
else if (SectionName == ".fini_array")
Type = ELF::SHT_FINI_ARRAY;
else if (SectionName == ".preinit_array")
Type = ELF::SHT_PREINIT_ARRAY;
} else {
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");
}
if (UseLastGroup) {
MCSectionSubPair CurrentSection = getStreamer().getCurrentSection();
if (const MCSectionELF *Section =
cast_or_null<MCSectionELF>(CurrentSection.first))
if (const MCSymbol *Group = Section->getGroup()) {
GroupName = Group->getName();
Flags |= ELF::SHF_GROUP;
}
}
SectionKind Kind = computeSectionKind(Flags, Size);
const MCSection *ELFSection = getContext().getELFSection(
SectionName, Type, Flags, Kind, Size, GroupName);
getStreamer().SwitchSection(ELFSection, Subsection);
if (getContext().getGenDwarfForAssembly()) {
auto &Sections = getContext().getGenDwarfSectionSyms();
auto InsertResult = Sections.insert(
std::make_pair(ELFSection, std::make_pair(nullptr, nullptr)));
if (InsertResult.second) {
if (getContext().getDwarfVersion() <= 2)
Warning(loc, "DWARF2 only supports one section per compilation unit");
MCSymbol *SectionStartSymbol = getContext().CreateTempSymbol();
getStreamer().EmitLabel(SectionStartSymbol);
InsertResult.first->second.first = SectionStartSymbol;
}
}
return false;
}
bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
if (PreviousSection.first == nullptr)
return TokError(".previous without corresponding .section");
getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second);
return false;
}
static MCSymbolAttr MCAttrForString(StringRef Type) {
return StringSwitch<MCSymbolAttr>(Type)
.Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
.Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
.Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
.Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
.Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
.Cases("STT_GNU_IFUNC", "gnu_indirect_function",
MCSA_ELF_TypeIndFunction)
.Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
.Default(MCSA_Invalid);
}
/// ParseDirectiveELFType
/// ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
/// ::= .type identifier , #attribute
/// ::= .type identifier , @attribute
/// ::= .type identifier , %attribute
/// ::= .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);
// NOTE the comma is optional in all cases. It is only documented as being
// optional in the first case, however, GAS will silently treat the comma as
// optional in all cases. Furthermore, although the documentation states that
// the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
// accepts both the upper case name as well as the lower case aliases.
if (getLexer().is(AsmToken::Comma))
Lex();
if (getLexer().isNot(AsmToken::Identifier) &&
getLexer().isNot(AsmToken::Hash) && getLexer().isNot(AsmToken::At) &&
getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::String))
return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
"'%<type>' or \"<type>\"");
if (getLexer().isNot(AsmToken::String) &&
getLexer().isNot(AsmToken::Identifier))
Lex();
SMLoc TypeLoc = getLexer().getLoc();
StringRef Type;
if (getParser().parseIdentifier(Type))
return TokError("expected symbol type in directive");
MCSymbolAttr Attr = MCAttrForString(Type);
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();
getStreamer().EmitIdent(Data);
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");
// ARM assembly uses @ for a comment...
// except when parsing the second parameter of the .symver directive.
// Force the next symbol to allow @ in the identifier, which is
// required for this directive and then reset it to its initial state.
const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
getLexer().setAllowAtInIdentifier(true);
Lex();
getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
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;
}
/// ParseDirectiveVersion
/// ::= .version string
bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
if (getLexer().isNot(AsmToken::String))
return TokError("unexpected token in '.version' directive");
StringRef Data = getTok().getIdentifier();
Lex();
const MCSection *Note =
getContext().getELFSection(".note", ELF::SHT_NOTE, 0,
SectionKind::getReadOnly());
getStreamer().PushSection();
getStreamer().SwitchSection(Note);
getStreamer().EmitIntValue(Data.size()+1, 4); // namesz.
getStreamer().EmitIntValue(0, 4); // descsz = 0 (no description).
getStreamer().EmitIntValue(1, 4); // type = NT_VERSION.
getStreamer().EmitBytes(Data); // name.
getStreamer().EmitIntValue(0, 1); // terminate the string.
getStreamer().EmitValueToAlignment(4); // ensure 4 byte alignment.
getStreamer().PopSection();
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;
}
bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) {
const MCExpr *Subsection = nullptr;
if (getLexer().isNot(AsmToken::EndOfStatement)) {
if (getParser().parseExpression(Subsection))
return true;
}
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token in directive");
getStreamer().SubSection(Subsection);
return false;
}
namespace llvm {
MCAsmParserExtension *createELFAsmParser() {
return new ELFAsmParser;
}
}
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