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dda73336ad22bd0b5ecda17040c50fb10fcbe5fb
clang-p2996/llvm/lib/MC/MCParser/ELFAsmParser.cpp
Fangrui Song 7620f03ef7 [MC] Parse SHF_LINK_ORDER argument before section group name (#77407) 
When both SHF_LINK_ORDER | SHF_GROUP flags are set, GNU assembler from
2.35 onwards (https://sourceware.org/PR25381
https://sourceware.org/binutils/docs/as/Section.html) parses the
SHF_LINK_ORDER argument before section group name, different from us.

This is unfortunate, but does not matter because the `.section` flag `o`
is a niche feature only used by compiler instrumentations, not adopted
by hand-written assembly, and using both flags is extremely rare. Let's
just match GNU assembler. There is another benefit: we now support
zero-flag section group with the SHF_LINK_ORDER flag, while previously
there isn't a syntax.

While here, print 'G' after 'o' to be clear that the 'G' argument is
parsed after the 'o' argument. To make the diff smaller, we don't print
'G' after 'w' in the absence of 'o' for now.
2024-01-09 10:42:34 -08:00

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//===- ELFAsmParser.cpp - ELF Assembly Parser -----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/MC/MCParser/MCAsmParserExtension.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/SMLoc.h"
#include <cassert>
#include <cstdint>
#include <utility>
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::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");
addDirectiveHandler<&ELFAsmParser::ParseDirectiveCGProfile>(".cg_profile");
}
// 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::getData());
}
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::getData());
}
bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) {
return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC |
ELF::SHF_WRITE,
SectionKind::getReadOnlyWithRel());
}
bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) {
return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_WRITE,
SectionKind::getData());
}
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);
bool ParseDirectiveCGProfile(StringRef, SMLoc);
private:
bool ParseSectionName(StringRef &SectionName);
bool ParseSectionArguments(bool IsPush, SMLoc loc);
unsigned parseSunStyleSectionFlags();
bool maybeParseSectionType(StringRef &TypeName);
bool parseMergeSize(int64_t &Size);
bool parseGroup(StringRef &GroupName, bool &IsComdat);
bool parseLinkedToSym(MCSymbolELF *&LinkedToSym);
bool maybeParseUniqueID(int64_t &UniqueID);
};
} // end anonymous namespace
/// 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)) {
while (true) {
StringRef Name;
if (getParser().parseIdentifier(Name))
return TokError("expected identifier");
if (getParser().discardLTOSymbol(Name)) {
if (getLexer().is(AsmToken::EndOfStatement))
break;
continue;
}
MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
getStreamer().emitSymbolAttribute(Sym, Attr);
if (getLexer().is(AsmToken::EndOfStatement))
break;
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected comma");
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;
}
Lex();
getStreamer().switchSection(getContext().getELFSection(Section, Type, Flags),
Subsection);
return false;
}
bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
StringRef Name;
if (getParser().parseIdentifier(Name))
return TokError("expected identifier");
MCSymbolELF *Sym = cast<MCSymbolELF>(getContext().getOrCreateSymbol(Name));
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected comma");
Lex();
const MCExpr *Expr;
if (getParser().parseExpression(Expr))
return true;
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("unexpected token");
Lex();
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;
}
while (!getParser().hasPendingError()) {
SMLoc PrevLoc = getLexer().getLoc();
if (getLexer().is(AsmToken::Comma) ||
getLexer().is(AsmToken::EndOfStatement))
break;
unsigned CurSize;
if (getLexer().is(AsmToken::String)) {
CurSize = getTok().getIdentifier().size() + 2;
Lex();
} else if (getLexer().is(AsmToken::Identifier)) {
CurSize = getTok().getIdentifier().size();
Lex();
} else {
CurSize = getTok().getString().size();
Lex();
}
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 unsigned parseSectionFlags(const Triple &TT, StringRef flagsStr,
bool *UseLastGroup) {
unsigned flags = 0;
// If a valid numerical value is set for the section flag, use it verbatim
if (!flagsStr.getAsInteger(0, flags))
return flags;
for (char i : flagsStr) {
switch (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 'o':
flags |= ELF::SHF_LINK_ORDER;
break;
case 'M':
flags |= ELF::SHF_MERGE;
break;
case 'S':
flags |= ELF::SHF_STRINGS;
break;
case 'T':
flags |= ELF::SHF_TLS;
break;
case 'c':
if (TT.getArch() != Triple::xcore)
return -1U;
flags |= ELF::XCORE_SHF_CP_SECTION;
break;
case 'd':
if (TT.getArch() != Triple::xcore)
return -1U;
flags |= ELF::XCORE_SHF_DP_SECTION;
break;
case 'y':
if (!(TT.isARM() || TT.isThumb()))
return -1U;
flags |= ELF::SHF_ARM_PURECODE;
break;
case 's':
if (TT.getArch() != Triple::hexagon)
return -1U;
flags |= ELF::SHF_HEX_GPREL;
break;
case 'G':
flags |= ELF::SHF_GROUP;
break;
case 'l':
if (TT.getArch() != Triple::x86_64)
return -1U;
flags |= ELF::SHF_X86_64_LARGE;
break;
case 'R':
if (TT.isOSSolaris())
flags |= ELF::SHF_SUNW_NODISCARD;
else
flags |= ELF::SHF_GNU_RETAIN;
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;
}
bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
return ParseSectionArguments(/*IsPush=*/false, loc);
}
bool ELFAsmParser::maybeParseSectionType(StringRef &TypeName) {
MCAsmLexer &L = getLexer();
if (L.isNot(AsmToken::Comma))
return false;
Lex();
if (L.isNot(AsmToken::At) && L.isNot(AsmToken::Percent) &&
L.isNot(AsmToken::String)) {
if (L.getAllowAtInIdentifier())
return TokError("expected '@<type>', '%<type>' or \"<type>\"");
else
return TokError("expected '%<type>' or \"<type>\"");
}
if (!L.is(AsmToken::String))
Lex();
if (L.is(AsmToken::Integer)) {
TypeName = getTok().getString();
Lex();
} else if (getParser().parseIdentifier(TypeName))
return TokError("expected identifier");
return false;
}
bool ELFAsmParser::parseMergeSize(int64_t &Size) {
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");
return false;
}
bool ELFAsmParser::parseGroup(StringRef &GroupName, bool &IsComdat) {
MCAsmLexer &L = getLexer();
if (L.isNot(AsmToken::Comma))
return TokError("expected group name");
Lex();
if (L.is(AsmToken::Integer)) {
GroupName = getTok().getString();
Lex();
} else if (getParser().parseIdentifier(GroupName)) {
return TokError("invalid group name");
}
if (L.is(AsmToken::Comma)) {
Lex();
StringRef Linkage;
if (getParser().parseIdentifier(Linkage))
return TokError("invalid linkage");
if (Linkage != "comdat")
return TokError("Linkage must be 'comdat'");
IsComdat = true;
} else {
IsComdat = false;
}
return false;
}
bool ELFAsmParser::parseLinkedToSym(MCSymbolELF *&LinkedToSym) {
MCAsmLexer &L = getLexer();
if (L.isNot(AsmToken::Comma))
return TokError("expected linked-to symbol");
Lex();
StringRef Name;
SMLoc StartLoc = L.getLoc();
if (getParser().parseIdentifier(Name)) {
if (getParser().getTok().getString() == "0") {
getParser().Lex();
LinkedToSym = nullptr;
return false;
}
return TokError("invalid linked-to symbol");
}
LinkedToSym = dyn_cast_or_null<MCSymbolELF>(getContext().lookupSymbol(Name));
if (!LinkedToSym || !LinkedToSym->isInSection())
return Error(StartLoc, "linked-to symbol is not in a section: " + Name);
return false;
}
bool ELFAsmParser::maybeParseUniqueID(int64_t &UniqueID) {
MCAsmLexer &L = getLexer();
if (L.isNot(AsmToken::Comma))
return false;
Lex();
StringRef UniqueStr;
if (getParser().parseIdentifier(UniqueStr))
return TokError("expected identifier");
if (UniqueStr != "unique")
return TokError("expected 'unique'");
if (L.isNot(AsmToken::Comma))
return TokError("expected commma");
Lex();
if (getParser().parseAbsoluteExpression(UniqueID))
return true;
if (UniqueID < 0)
return TokError("unique id must be positive");
if (!isUInt<32>(UniqueID) || UniqueID == ~0U)
return TokError("unique id is too large");
return false;
}
static bool hasPrefix(StringRef SectionName, StringRef Prefix) {
return SectionName.consume_front(Prefix) &&
(SectionName.empty() || SectionName[0] == '.');
}
static bool allowSectionTypeMismatch(const Triple &TT, StringRef SectionName,
unsigned Type) {
if (TT.getArch() == Triple::x86_64) {
// x86-64 psABI names SHT_X86_64_UNWIND as the canonical type for .eh_frame,
// but GNU as emits SHT_PROGBITS .eh_frame for .cfi_* directives. Don't
// error for SHT_PROGBITS .eh_frame
return SectionName == ".eh_frame" && Type == ELF::SHT_PROGBITS;
}
if (TT.isMIPS()) {
// MIPS .debug_* sections should have SHT_MIPS_DWARF section type to
// distinguish among sections contain DWARF and ECOFF debug formats,
// but in assembly files these sections have SHT_PROGBITS type.
return SectionName.starts_with(".debug_") && Type == ELF::SHT_PROGBITS;
}
return false;
}
bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
StringRef SectionName;
if (ParseSectionName(SectionName))
return TokError("expected identifier");
StringRef TypeName;
int64_t Size = 0;
StringRef GroupName;
bool IsComdat = false;
unsigned Flags = 0;
unsigned extraFlags = 0;
const MCExpr *Subsection = nullptr;
bool UseLastGroup = false;
MCSymbolELF *LinkedToSym = nullptr;
int64_t UniqueID = ~0;
// Set the defaults first.
if (hasPrefix(SectionName, ".rodata") || SectionName == ".rodata1")
Flags |= ELF::SHF_ALLOC;
else if (SectionName == ".fini" || SectionName == ".init" ||
hasPrefix(SectionName, ".text"))
Flags |= ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
else if (hasPrefix(SectionName, ".data") || SectionName == ".data1" ||
hasPrefix(SectionName, ".bss") ||
hasPrefix(SectionName, ".init_array") ||
hasPrefix(SectionName, ".fini_array") ||
hasPrefix(SectionName, ".preinit_array"))
Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE;
else if (hasPrefix(SectionName, ".tdata") || hasPrefix(SectionName, ".tbss"))
Flags |= ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_TLS;
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();
}
if (getLexer().isNot(AsmToken::String)) {
if (getLexer().isNot(AsmToken::Hash))
return TokError("expected string");
extraFlags = parseSunStyleSectionFlags();
} else {
StringRef FlagsStr = getTok().getStringContents();
Lex();
extraFlags = parseSectionFlags(getContext().getTargetTriple(), 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 (maybeParseSectionType(TypeName))
return true;
MCAsmLexer &L = getLexer();
if (TypeName.empty()) {
if (Mergeable)
return TokError("Mergeable section must specify the type");
if (Group)
return TokError("Group section must specify the type");
if (L.isNot(AsmToken::EndOfStatement))
return TokError("expected end of directive");
}
if (Mergeable)
if (parseMergeSize(Size))
return true;
if (Flags & ELF::SHF_LINK_ORDER)
if (parseLinkedToSym(LinkedToSym))
return true;
if (Group)
if (parseGroup(GroupName, IsComdat))
return true;
if (maybeParseUniqueID(UniqueID))
return true;
}
EndStmt:
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("expected end of directive");
Lex();
unsigned Type = ELF::SHT_PROGBITS;
if (TypeName.empty()) {
if (SectionName.starts_with(".note"))
Type = ELF::SHT_NOTE;
else if (hasPrefix(SectionName, ".init_array"))
Type = ELF::SHT_INIT_ARRAY;
else if (hasPrefix(SectionName, ".bss"))
Type = ELF::SHT_NOBITS;
else if (hasPrefix(SectionName, ".tbss"))
Type = ELF::SHT_NOBITS;
else if (hasPrefix(SectionName, ".fini_array"))
Type = ELF::SHT_FINI_ARRAY;
else if (hasPrefix(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 if (TypeName == "llvm_odrtab")
Type = ELF::SHT_LLVM_ODRTAB;
else if (TypeName == "llvm_linker_options")
Type = ELF::SHT_LLVM_LINKER_OPTIONS;
else if (TypeName == "llvm_call_graph_profile")
Type = ELF::SHT_LLVM_CALL_GRAPH_PROFILE;
else if (TypeName == "llvm_dependent_libraries")
Type = ELF::SHT_LLVM_DEPENDENT_LIBRARIES;
else if (TypeName == "llvm_sympart")
Type = ELF::SHT_LLVM_SYMPART;
else if (TypeName == "llvm_bb_addr_map")
Type = ELF::SHT_LLVM_BB_ADDR_MAP;
else if (TypeName == "llvm_offloading")
Type = ELF::SHT_LLVM_OFFLOADING;
else if (TypeName == "llvm_lto")
Type = ELF::SHT_LLVM_LTO;
else if (TypeName.getAsInteger(0, Type))
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();
IsComdat = Section->isComdat();
Flags |= ELF::SHF_GROUP;
}
}
MCSectionELF *Section =
getContext().getELFSection(SectionName, Type, Flags, Size, GroupName,
IsComdat, UniqueID, LinkedToSym);
getStreamer().switchSection(Section, Subsection);
// Check that flags are used consistently. However, the GNU assembler permits
// to leave out in subsequent uses of the same sections; for compatibility,
// do likewise.
if (!TypeName.empty() && Section->getType() != Type &&
!allowSectionTypeMismatch(getContext().getTargetTriple(), SectionName,
Type))
Error(loc, "changed section type for " + SectionName + ", expected: 0x" +
utohexstr(Section->getType()));
if ((extraFlags || Size || !TypeName.empty()) && Section->getFlags() != Flags)
Error(loc, "changed section flags for " + SectionName + ", expected: 0x" +
utohexstr(Section->getFlags()));
if ((extraFlags || Size || !TypeName.empty()) &&
Section->getEntrySize() != Size)
Error(loc, "changed section entsize for " + SectionName +
", expected: " + Twine(Section->getEntrySize()));
if (getContext().getGenDwarfForAssembly() &&
(Section->getFlags() & ELF::SHF_ALLOC) &&
(Section->getFlags() & ELF::SHF_EXECINSTR)) {
bool InsertResult = getContext().addGenDwarfSection(Section);
if (InsertResult) {
if (getContext().getDwarfVersion() <= 2)
Warning(loc, "DWARF2 only supports one section per compilation unit");
if (!Section->getBeginSymbol()) {
MCSymbol *SectionStartSymbol = getContext().createTempSymbol();
getStreamer().emitLabel(SectionStartSymbol);
Section->setBeginSymbol(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");
// 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::Percent) &&
getLexer().isNot(AsmToken::String)) {
if (!getLexer().getAllowAtInIdentifier())
return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', "
"'%<type>' or \"<type>\"");
else if (getLexer().isNot(AsmToken::At))
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");
MCSymbolAttr Attr = MCAttrForString(Type);
if (Attr == MCSA_Invalid)
return Error(TypeLoc, "unsupported attribute");
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("expected end of directive");
Lex();
getStreamer().emitSymbolAttribute(Sym, Attr);
return false;
}
/// ParseDirectiveIdent
/// ::= .ident string
bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
if (getLexer().isNot(AsmToken::String))
return TokError("expected string");
StringRef Data = getTok().getIdentifier();
Lex();
if (getLexer().isNot(AsmToken::EndOfStatement))
return TokError("expected end of directive");
Lex();
getStreamer().emitIdent(Data);
return false;
}
/// ParseDirectiveSymver
/// ::= .symver foo, bar2@zed
bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
StringRef OriginalName, Name, Action;
if (getParser().parseIdentifier(OriginalName))
return TokError("expected identifier");
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);
if (getParser().parseIdentifier(Name))
return TokError("expected identifier");
if (!Name.contains('@'))
return TokError("expected a '@' in the name");
bool KeepOriginalSym = !Name.contains("@@@");
if (parseOptionalToken(AsmToken::Comma)) {
if (getParser().parseIdentifier(Action) || Action != "remove")
return TokError("expected 'remove'");
KeepOriginalSym = false;
}
(void)parseOptionalToken(AsmToken::EndOfStatement);
getStreamer().emitELFSymverDirective(
getContext().getOrCreateSymbol(OriginalName), Name, KeepOriginalSym);
return false;
}
/// ParseDirectiveVersion
/// ::= .version string
bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
if (getLexer().isNot(AsmToken::String))
return TokError("expected string");
StringRef Data = getTok().getIdentifier();
Lex();
MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0);
getStreamer().pushSection();
getStreamer().switchSection(Note);
getStreamer().emitInt32(Data.size() + 1); // namesz
getStreamer().emitInt32(0); // descsz = 0 (no description).
getStreamer().emitInt32(1); // type = NT_VERSION
getStreamer().emitBytes(Data); // name
getStreamer().emitInt8(0); // NUL
getStreamer().emitValueToAlignment(Align(4));
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");
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected a comma");
Lex();
StringRef Name;
if (getParser().parseIdentifier(Name))
return TokError("expected identifier");
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("expected end of directive");
Lex();
getStreamer().subSection(Subsection);
return false;
}
bool ELFAsmParser::ParseDirectiveCGProfile(StringRef S, SMLoc Loc) {
return MCAsmParserExtension::ParseDirectiveCGProfile(S, Loc);
}
namespace llvm {
MCAsmParserExtension *createELFAsmParser() {
return new ELFAsmParser;
}
} // end namespace llvm
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