mirror of
https://github.com/opnsense/src.git
synced 2026-03-03 05:41:01 -05:00
dd6029ff3a
There are several bugfixes in this update, but the most important one is to ensure __start_ and __stop_ symbols for linker sets and kernel module metadata are always emitted in object files: http://llvm.org/bugs/show_bug.cgi?id=9292 Before this fix, if you compiled kernel modules with clang, they would not be properly processed by kldxref, and if they had any dependencies, the kernel would fail to load those. Another problem occurred when attempting to mount a tmpfs filesystem, which would result in 'operation not supported by device'.
533 lines
17 KiB
C++
533 lines
17 KiB
C++
//===- ELFAsmParser.cpp - ELF Assembly Parser -----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCParser/MCAsmParserExtension.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCParser/MCAsmLexer.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/Support/ELF.h"
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using namespace llvm;
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namespace {
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class ELFAsmParser : public MCAsmParserExtension {
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template<bool (ELFAsmParser::*Handler)(StringRef, SMLoc)>
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void AddDirectiveHandler(StringRef Directive) {
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getParser().AddDirectiveHandler(this, Directive,
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HandleDirective<ELFAsmParser, Handler>);
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}
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bool ParseSectionSwitch(StringRef Section, unsigned Type,
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unsigned Flags, SectionKind Kind);
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bool SeenIdent;
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public:
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ELFAsmParser() : SeenIdent(false) {
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BracketExpressionsSupported = true;
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}
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virtual void Initialize(MCAsmParser &Parser) {
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// Call the base implementation.
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this->MCAsmParserExtension::Initialize(Parser);
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRelRoLocal>(".data.rel.ro.local");
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AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectivePushSection>(".pushsection");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
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AddDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
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}
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// FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
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// the best way for us to get access to it?
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bool ParseSectionDirectiveData(StringRef, SMLoc) {
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return ParseSectionSwitch(".data", ELF::SHT_PROGBITS,
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ELF::SHF_WRITE |ELF::SHF_ALLOC,
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SectionKind::getDataRel());
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}
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bool ParseSectionDirectiveText(StringRef, SMLoc) {
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return ParseSectionSwitch(".text", ELF::SHT_PROGBITS,
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ELF::SHF_EXECINSTR |
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ELF::SHF_ALLOC, SectionKind::getText());
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}
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bool ParseSectionDirectiveBSS(StringRef, SMLoc) {
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return ParseSectionSwitch(".bss", ELF::SHT_NOBITS,
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ELF::SHF_WRITE |
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ELF::SHF_ALLOC, SectionKind::getBSS());
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}
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bool ParseSectionDirectiveRoData(StringRef, SMLoc) {
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return ParseSectionSwitch(".rodata", ELF::SHT_PROGBITS,
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ELF::SHF_ALLOC,
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SectionKind::getReadOnly());
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}
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bool ParseSectionDirectiveTData(StringRef, SMLoc) {
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return ParseSectionSwitch(".tdata", ELF::SHT_PROGBITS,
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ELF::SHF_ALLOC |
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ELF::SHF_TLS | ELF::SHF_WRITE,
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SectionKind::getThreadData());
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}
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bool ParseSectionDirectiveTBSS(StringRef, SMLoc) {
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return ParseSectionSwitch(".tbss", ELF::SHT_NOBITS,
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ELF::SHF_ALLOC |
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ELF::SHF_TLS | ELF::SHF_WRITE,
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SectionKind::getThreadBSS());
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}
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bool ParseSectionDirectiveDataRel(StringRef, SMLoc) {
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return ParseSectionSwitch(".data.rel", ELF::SHT_PROGBITS,
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ELF::SHF_ALLOC |
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ELF::SHF_WRITE,
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SectionKind::getDataRel());
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}
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bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) {
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return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS,
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ELF::SHF_ALLOC |
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ELF::SHF_WRITE,
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SectionKind::getReadOnlyWithRel());
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}
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bool ParseSectionDirectiveDataRelRoLocal(StringRef, SMLoc) {
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return ParseSectionSwitch(".data.rel.ro.local", ELF::SHT_PROGBITS,
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ELF::SHF_ALLOC |
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ELF::SHF_WRITE,
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SectionKind::getReadOnlyWithRelLocal());
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}
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bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) {
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return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS,
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ELF::SHF_ALLOC |
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ELF::SHF_WRITE,
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SectionKind::getDataRel());
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}
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bool ParseDirectivePushSection(StringRef, SMLoc);
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bool ParseDirectivePopSection(StringRef, SMLoc);
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bool ParseDirectiveSection(StringRef, SMLoc);
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bool ParseDirectiveSize(StringRef, SMLoc);
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bool ParseDirectivePrevious(StringRef, SMLoc);
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bool ParseDirectiveType(StringRef, SMLoc);
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bool ParseDirectiveIdent(StringRef, SMLoc);
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bool ParseDirectiveSymver(StringRef, SMLoc);
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bool ParseDirectiveWeakref(StringRef, SMLoc);
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private:
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bool ParseSectionName(StringRef &SectionName);
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};
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}
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bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
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unsigned Flags, SectionKind Kind) {
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if (getLexer().isNot(AsmToken::EndOfStatement))
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return TokError("unexpected token in section switching directive");
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Lex();
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getStreamer().SwitchSection(getContext().getELFSection(
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Section, Type, Flags, Kind));
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return false;
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}
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bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
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StringRef Name;
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if (getParser().ParseIdentifier(Name))
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return TokError("expected identifier in directive");
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MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);;
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if (getLexer().isNot(AsmToken::Comma))
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return TokError("unexpected token in directive");
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Lex();
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const MCExpr *Expr;
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if (getParser().ParseExpression(Expr))
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return true;
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if (getLexer().isNot(AsmToken::EndOfStatement))
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return TokError("unexpected token in directive");
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getStreamer().EmitELFSize(Sym, Expr);
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return false;
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}
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bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
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// A section name can contain -, so we cannot just use
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// ParseIdentifier.
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SMLoc FirstLoc = getLexer().getLoc();
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unsigned Size = 0;
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if (getLexer().is(AsmToken::String)) {
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SectionName = getTok().getIdentifier();
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Lex();
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return false;
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}
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for (;;) {
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StringRef Tmp;
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unsigned CurSize;
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SMLoc PrevLoc = getLexer().getLoc();
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if (getLexer().is(AsmToken::Minus)) {
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CurSize = 1;
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Lex(); // Consume the "-".
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} else if (getLexer().is(AsmToken::String)) {
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CurSize = getTok().getIdentifier().size() + 2;
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Lex();
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} else if (getLexer().is(AsmToken::Identifier)) {
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CurSize = getTok().getIdentifier().size();
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Lex();
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} else {
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break;
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}
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Size += CurSize;
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SectionName = StringRef(FirstLoc.getPointer(), Size);
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// Make sure the following token is adjacent.
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if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
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break;
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}
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if (Size == 0)
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return true;
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return false;
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}
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static SectionKind computeSectionKind(unsigned Flags) {
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if (Flags & ELF::SHF_EXECINSTR)
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return SectionKind::getText();
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if (Flags & ELF::SHF_TLS)
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return SectionKind::getThreadData();
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return SectionKind::getDataRel();
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}
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static int parseSectionFlags(StringRef flagsStr) {
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int flags = 0;
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for (unsigned i = 0; i < flagsStr.size(); i++) {
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switch (flagsStr[i]) {
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case 'a':
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flags |= ELF::SHF_ALLOC;
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break;
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case 'x':
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flags |= ELF::SHF_EXECINSTR;
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break;
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case 'w':
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flags |= ELF::SHF_WRITE;
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break;
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case 'M':
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flags |= ELF::SHF_MERGE;
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break;
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case 'S':
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flags |= ELF::SHF_STRINGS;
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break;
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case 'T':
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flags |= ELF::SHF_TLS;
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break;
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case 'c':
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flags |= ELF::XCORE_SHF_CP_SECTION;
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break;
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case 'd':
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flags |= ELF::XCORE_SHF_DP_SECTION;
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break;
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case 'G':
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flags |= ELF::SHF_GROUP;
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break;
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default:
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return -1;
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}
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}
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return flags;
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}
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bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
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getStreamer().PushSection();
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if (ParseDirectiveSection(s, loc)) {
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getStreamer().PopSection();
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return true;
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}
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return false;
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}
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bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
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if (!getStreamer().PopSection())
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return TokError(".popsection without corresponding .pushsection");
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return false;
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}
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// FIXME: This is a work in progress.
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bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
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StringRef SectionName;
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if (ParseSectionName(SectionName))
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return TokError("expected identifier in directive");
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StringRef TypeName;
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int64_t Size = 0;
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StringRef GroupName;
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unsigned Flags = 0;
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// Set the defaults first.
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if (SectionName == ".fini" || SectionName == ".init" ||
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SectionName == ".rodata")
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Flags |= ELF::SHF_ALLOC;
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if (SectionName == ".fini" || SectionName == ".init")
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Flags |= ELF::SHF_EXECINSTR;
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if (getLexer().is(AsmToken::Comma)) {
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Lex();
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if (getLexer().isNot(AsmToken::String))
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return TokError("expected string in directive");
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StringRef FlagsStr = getTok().getStringContents();
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Lex();
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int extraFlags = parseSectionFlags(FlagsStr);
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if (extraFlags < 0)
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return TokError("unknown flag");
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Flags |= extraFlags;
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bool Mergeable = Flags & ELF::SHF_MERGE;
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bool Group = Flags & ELF::SHF_GROUP;
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if (getLexer().isNot(AsmToken::Comma)) {
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if (Mergeable)
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return TokError("Mergeable section must specify the type");
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if (Group)
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return TokError("Group section must specify the type");
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} else {
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Lex();
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if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
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return TokError("expected '@' or '%' before type");
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Lex();
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if (getParser().ParseIdentifier(TypeName))
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return TokError("expected identifier in directive");
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if (Mergeable) {
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if (getLexer().isNot(AsmToken::Comma))
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return TokError("expected the entry size");
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Lex();
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if (getParser().ParseAbsoluteExpression(Size))
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return true;
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if (Size <= 0)
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return TokError("entry size must be positive");
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}
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if (Group) {
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if (getLexer().isNot(AsmToken::Comma))
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return TokError("expected group name");
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Lex();
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if (getParser().ParseIdentifier(GroupName))
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return true;
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if (getLexer().is(AsmToken::Comma)) {
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Lex();
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StringRef Linkage;
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if (getParser().ParseIdentifier(Linkage))
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return true;
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if (Linkage != "comdat")
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return TokError("Linkage must be 'comdat'");
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}
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}
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}
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}
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if (getLexer().isNot(AsmToken::EndOfStatement))
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return TokError("unexpected token in directive");
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unsigned Type = ELF::SHT_PROGBITS;
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if (!TypeName.empty()) {
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if (TypeName == "init_array")
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Type = ELF::SHT_INIT_ARRAY;
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else if (TypeName == "fini_array")
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Type = ELF::SHT_FINI_ARRAY;
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else if (TypeName == "preinit_array")
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Type = ELF::SHT_PREINIT_ARRAY;
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else if (TypeName == "nobits")
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Type = ELF::SHT_NOBITS;
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else if (TypeName == "progbits")
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Type = ELF::SHT_PROGBITS;
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else if (TypeName == "note")
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Type = ELF::SHT_NOTE;
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else if (TypeName == "unwind")
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Type = ELF::SHT_X86_64_UNWIND;
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else
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return TokError("unknown section type");
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}
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SectionKind Kind = computeSectionKind(Flags);
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getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
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Flags, Kind, Size,
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GroupName));
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return false;
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}
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bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
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const MCSection *PreviousSection = getStreamer().getPreviousSection();
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if (PreviousSection == NULL)
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return TokError(".previous without corresponding .section");
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getStreamer().SwitchSection(PreviousSection);
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return false;
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}
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/// ParseDirectiveELFType
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/// ::= .type identifier , @attribute
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bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
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StringRef Name;
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if (getParser().ParseIdentifier(Name))
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return TokError("expected identifier in directive");
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// Handle the identifier as the key symbol.
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MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
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if (getLexer().isNot(AsmToken::Comma))
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return TokError("unexpected token in '.type' directive");
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Lex();
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if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
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return TokError("expected '@' or '%' before type");
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Lex();
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StringRef Type;
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SMLoc TypeLoc;
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TypeLoc = getLexer().getLoc();
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if (getParser().ParseIdentifier(Type))
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return TokError("expected symbol type in directive");
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MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Type)
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.Case("function", MCSA_ELF_TypeFunction)
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.Case("object", MCSA_ELF_TypeObject)
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.Case("tls_object", MCSA_ELF_TypeTLS)
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.Case("common", MCSA_ELF_TypeCommon)
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.Case("notype", MCSA_ELF_TypeNoType)
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.Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
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.Default(MCSA_Invalid);
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if (Attr == MCSA_Invalid)
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return Error(TypeLoc, "unsupported attribute in '.type' directive");
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if (getLexer().isNot(AsmToken::EndOfStatement))
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return TokError("unexpected token in '.type' directive");
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Lex();
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getStreamer().EmitSymbolAttribute(Sym, Attr);
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return false;
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}
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/// ParseDirectiveIdent
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/// ::= .ident string
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bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
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if (getLexer().isNot(AsmToken::String))
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return TokError("unexpected token in '.ident' directive");
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StringRef Data = getTok().getIdentifier();
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Lex();
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const MCSection *Comment =
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getContext().getELFSection(".comment", ELF::SHT_PROGBITS,
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ELF::SHF_MERGE |
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ELF::SHF_STRINGS,
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SectionKind::getReadOnly(),
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1, "");
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getStreamer().PushSection();
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getStreamer().SwitchSection(Comment);
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if (!SeenIdent) {
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getStreamer().EmitIntValue(0, 1);
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SeenIdent = true;
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}
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getStreamer().EmitBytes(Data, 0);
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getStreamer().EmitIntValue(0, 1);
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getStreamer().PopSection();
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return false;
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}
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/// ParseDirectiveSymver
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/// ::= .symver foo, bar2@zed
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bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
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StringRef Name;
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if (getParser().ParseIdentifier(Name))
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return TokError("expected identifier in directive");
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if (getLexer().isNot(AsmToken::Comma))
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return TokError("expected a comma");
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Lex();
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StringRef AliasName;
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if (getParser().ParseIdentifier(AliasName))
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return TokError("expected identifier in directive");
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if (AliasName.find('@') == StringRef::npos)
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return TokError("expected a '@' in the name");
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MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
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MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
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const MCExpr *Value = MCSymbolRefExpr::Create(Sym, getContext());
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getStreamer().EmitAssignment(Alias, Value);
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return false;
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}
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/// ParseDirectiveWeakref
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/// ::= .weakref foo, bar
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bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
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// FIXME: Share code with the other alias building directives.
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StringRef AliasName;
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if (getParser().ParseIdentifier(AliasName))
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return TokError("expected identifier in directive");
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if (getLexer().isNot(AsmToken::Comma))
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return TokError("expected a comma");
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Lex();
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StringRef Name;
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if (getParser().ParseIdentifier(Name))
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return TokError("expected identifier in directive");
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MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
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MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
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getStreamer().EmitWeakReference(Alias, Sym);
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return false;
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}
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namespace llvm {
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MCAsmParserExtension *createELFAsmParser() {
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return new ELFAsmParser;
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}
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}
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