diff options
Diffstat (limited to 'llvm/tools/llvm-objcopy/ELF/Object.cpp')
-rw-r--r-- | llvm/tools/llvm-objcopy/ELF/Object.cpp | 173 |
1 files changed, 87 insertions, 86 deletions
diff --git a/llvm/tools/llvm-objcopy/ELF/Object.cpp b/llvm/tools/llvm-objcopy/ELF/Object.cpp index ad53c75663ec7..e15fb24f4c425 100644 --- a/llvm/tools/llvm-objcopy/ELF/Object.cpp +++ b/llvm/tools/llvm-objcopy/ELF/Object.cpp @@ -65,6 +65,7 @@ void SectionBase::finalize() {} void SectionBase::markSymbols() {} void SectionBase::replaceSectionReferences( const DenseMap<SectionBase *, SectionBase *> &) {} +void SectionBase::onRemove() {} template <class ELFT> void ELFWriter<ELFT>::writeShdr(const SectionBase &Sec) { uint8_t *B = Buf.getBufferStart() + Sec.HeaderOffset; @@ -111,7 +112,9 @@ void ELFSectionSizer<ELFT>::visit(RelocationSection &Sec) { template <class ELFT> void ELFSectionSizer<ELFT>::visit(GnuDebugLinkSection &Sec) {} -template <class ELFT> void ELFSectionSizer<ELFT>::visit(GroupSection &Sec) {} +template <class ELFT> void ELFSectionSizer<ELFT>::visit(GroupSection &Sec) { + Sec.Size = sizeof(Elf_Word) + Sec.GroupMembers.size() * sizeof(Elf_Word); +} template <class ELFT> void ELFSectionSizer<ELFT>::visit(SectionIndexSection &Sec) {} @@ -605,6 +608,7 @@ static bool isValidReservedSectionIndex(uint16_t Index, uint16_t Machine) { if (Machine == EM_HEXAGON) { switch (Index) { case SHN_HEXAGON_SCOMMON: + case SHN_HEXAGON_SCOMMON_1: case SHN_HEXAGON_SCOMMON_2: case SHN_HEXAGON_SCOMMON_4: case SHN_HEXAGON_SCOMMON_8: @@ -741,7 +745,7 @@ void SymbolTableSection::prepareForLayout() { // Reserve proper amount of space in section index table, so we can // layout sections correctly. We will fill the table with correct // indexes later in fillShdnxTable. - if (SectionIndexTable) + if (SectionIndexTable) SectionIndexTable->reserve(Symbols.size()); // Add all of our strings to SymbolNames so that SymbolNames has the right @@ -963,8 +967,24 @@ Error Section::removeSectionReferences( } void GroupSection::finalize() { - this->Info = Sym->Index; - this->Link = SymTab->Index; + this->Info = Sym ? Sym->Index : 0; + this->Link = SymTab ? SymTab->Index : 0; +} + +Error GroupSection::removeSectionReferences( + bool AllowBrokenLinks, function_ref<bool(const SectionBase *)> ToRemove) { + if (ToRemove(SymTab)) { + if (!AllowBrokenLinks) + return createStringError( + llvm::errc::invalid_argument, + "section '.symtab' cannot be removed because it is " + "referenced by the group section '%s'", + this->Name.data()); + SymTab = nullptr; + Sym = nullptr; + } + llvm::erase_if(GroupMembers, ToRemove); + return Error::success(); } Error GroupSection::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) { @@ -988,6 +1008,13 @@ void GroupSection::replaceSectionReferences( Sec = To; } +void GroupSection::onRemove() { + // As the header section of the group is removed, drop the Group flag in its + // former members. + for (SectionBase *Sec : GroupMembers) + Sec->Flags &= ~SHF_GROUP; +} + void Section::initialize(SectionTableRef SecTable) { if (Link == ELF::SHN_UNDEF) return; @@ -1101,14 +1128,6 @@ static bool compareSegmentsByOffset(const Segment *A, const Segment *B) { return A->Index < B->Index; } -static bool compareSegmentsByPAddr(const Segment *A, const Segment *B) { - if (A->PAddr < B->PAddr) - return true; - if (A->PAddr > B->PAddr) - return false; - return A->Index < B->Index; -} - void BasicELFBuilder::initFileHeader() { Obj->Flags = 0x0; Obj->Type = ET_REL; @@ -1241,7 +1260,7 @@ std::unique_ptr<Object> IHexELFBuilder::build() { template <class ELFT> void ELFBuilder<ELFT>::setParentSegment(Segment &Child) { for (Segment &Parent : Obj.segments()) { // Every segment will overlap with itself but we don't want a segment to - // be it's own parent so we avoid that situation. + // be its own parent so we avoid that situation. if (&Child != &Parent && segmentOverlapsSegment(Child, Parent)) { // We want a canonical "most parental" segment but this requires // inspecting the ParentSegment. @@ -1330,18 +1349,20 @@ void ELFBuilder<ELFT>::initGroupSection(GroupSection *GroupSec) { error("invalid alignment " + Twine(GroupSec->Align) + " of group section '" + GroupSec->Name + "'"); SectionTableRef SecTable = Obj.sections(); - auto SymTab = SecTable.template getSectionOfType<SymbolTableSection>( - GroupSec->Link, - "link field value '" + Twine(GroupSec->Link) + "' in section '" + - GroupSec->Name + "' is invalid", - "link field value '" + Twine(GroupSec->Link) + "' in section '" + - GroupSec->Name + "' is not a symbol table"); - Symbol *Sym = SymTab->getSymbolByIndex(GroupSec->Info); - if (!Sym) - error("info field value '" + Twine(GroupSec->Info) + "' in section '" + - GroupSec->Name + "' is not a valid symbol index"); - GroupSec->setSymTab(SymTab); - GroupSec->setSymbol(Sym); + if (GroupSec->Link != SHN_UNDEF) { + auto SymTab = SecTable.template getSectionOfType<SymbolTableSection>( + GroupSec->Link, + "link field value '" + Twine(GroupSec->Link) + "' in section '" + + GroupSec->Name + "' is invalid", + "link field value '" + Twine(GroupSec->Link) + "' in section '" + + GroupSec->Name + "' is not a symbol table"); + Symbol *Sym = SymTab->getSymbolByIndex(GroupSec->Info); + if (!Sym) + error("info field value '" + Twine(GroupSec->Info) + "' in section '" + + GroupSec->Name + "' is not a valid symbol index"); + GroupSec->setSymTab(SymTab); + GroupSec->setSymbol(Sym); + } if (GroupSec->Contents.size() % sizeof(ELF::Elf32_Word) || GroupSec->Contents.empty()) error("the content of the section " + GroupSec->Name + " is malformed"); @@ -1520,7 +1541,7 @@ template <class ELFT> void ELFBuilder<ELFT>::readSectionHeaders() { continue; } auto &Sec = makeSection(Shdr); - Sec.Name = unwrapOrError(ElfFile.getSectionName(&Shdr)); + Sec.Name = std::string(unwrapOrError(ElfFile.getSectionName(&Shdr))); Sec.Type = Sec.OriginalType = Shdr.sh_type; Sec.Flags = Sec.OriginalFlags = Shdr.sh_flags; Sec.Addr = Shdr.sh_addr; @@ -1567,27 +1588,7 @@ template <class ELFT> void ELFBuilder<ELFT>::readSections(bool EnsureSymtab) { Obj.SymbolTable->initialize(Obj.sections()); initSymbolTable(Obj.SymbolTable); } else if (EnsureSymtab) { - // Reuse an existing SHT_STRTAB section if it exists. - StringTableSection *StrTab = nullptr; - for (auto &Sec : Obj.sections()) { - if (Sec.Type == ELF::SHT_STRTAB && !(Sec.Flags & SHF_ALLOC)) { - StrTab = static_cast<StringTableSection *>(&Sec); - - // Prefer a string table that is not the section header string table, if - // such a table exists. - if (Obj.SectionNames != &Sec) - break; - } - } - if (!StrTab) - StrTab = &Obj.addSection<StringTableSection>(); - - SymbolTableSection &SymTab = Obj.addSection<SymbolTableSection>(); - SymTab.Name = ".symtab"; - SymTab.Link = StrTab->Index; - SymTab.initialize(Obj.sections()); - SymTab.addSymbol("", 0, 0, nullptr, 0, 0, 0, 0); - Obj.SymbolTable = &SymTab; + Obj.addNewSymbolTable(); } // Now that all sections and symbols have been added we can add @@ -1846,6 +1847,7 @@ Error Object::removeSections(bool AllowBrokenLinks, for (auto &RemoveSec : make_range(Iter, std::end(Sections))) { for (auto &Segment : Segments) Segment->removeSection(RemoveSec.get()); + RemoveSec->onRemove(); RemoveSections.insert(RemoveSec.get()); } @@ -1878,6 +1880,33 @@ Error Object::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) { return Error::success(); } +void Object::addNewSymbolTable() { + assert(!SymbolTable && "Object must not has a SymbolTable."); + + // Reuse an existing SHT_STRTAB section if it exists. + StringTableSection *StrTab = nullptr; + for (SectionBase &Sec : sections()) { + if (Sec.Type == ELF::SHT_STRTAB && !(Sec.Flags & SHF_ALLOC)) { + StrTab = static_cast<StringTableSection *>(&Sec); + + // Prefer a string table that is not the section header string table, if + // such a table exists. + if (SectionNames != &Sec) + break; + } + } + if (!StrTab) + StrTab = &addSection<StringTableSection>(); + + SymbolTableSection &SymTab = addSection<SymbolTableSection>(); + SymTab.Name = ".symtab"; + SymTab.Link = StrTab->Index; + SymTab.initialize(sections()); + SymTab.addSymbol("", 0, 0, nullptr, 0, 0, 0, 0); + + SymbolTable = &SymTab; +} + void Object::sortSections() { // Use stable_sort to maintain the original ordering as closely as possible. llvm::stable_sort(Sections, [](const SecPtr &A, const SecPtr &B) { @@ -1902,8 +1931,7 @@ static void orderSegments(std::vector<Segment *> &Segments) { // returns an Offset one past the end of the last segment. static uint64_t layoutSegments(std::vector<Segment *> &Segments, uint64_t Offset) { - assert(std::is_sorted(std::begin(Segments), std::end(Segments), - compareSegmentsByOffset)); + assert(llvm::is_sorted(Segments, compareSegmentsByOffset)); // The only way a segment should move is if a section was between two // segments and that section was removed. If that section isn't in a segment // then it's acceptable, but not ideal, to simply move it to after the @@ -2225,56 +2253,29 @@ Error BinaryWriter::write() { } Error BinaryWriter::finalize() { - // We need a temporary list of segments that has a special order to it - // so that we know that anytime ->ParentSegment is set that segment has - // already had it's offset properly set. We only want to consider the segments - // that will affect layout of allocated sections so we only add those. - std::vector<Segment *> OrderedSegments; - for (const SectionBase &Sec : Obj.allocSections()) - if (Sec.ParentSegment != nullptr) - OrderedSegments.push_back(Sec.ParentSegment); - - // For binary output, we're going to use physical addresses instead of - // virtual addresses, since a binary output is used for cases like ROM - // loading and physical addresses are intended for ROM loading. - // However, if no segment has a physical address, we'll fallback to using - // virtual addresses for all. - if (all_of(OrderedSegments, - [](const Segment *Seg) { return Seg->PAddr == 0; })) - for (Segment *Seg : OrderedSegments) - Seg->PAddr = Seg->VAddr; - - llvm::stable_sort(OrderedSegments, compareSegmentsByPAddr); - - // Because we add a ParentSegment for each section we might have duplicate - // segments in OrderedSegments. If there were duplicates then layoutSegments - // would do very strange things. - auto End = - std::unique(std::begin(OrderedSegments), std::end(OrderedSegments)); - OrderedSegments.erase(End, std::end(OrderedSegments)); - // Compute the section LMA based on its sh_offset and the containing segment's - // p_offset and p_paddr. Also compute the minimum LMA of all sections as - // MinAddr. In the output, the contents between address 0 and MinAddr will be - // skipped. + // p_offset and p_paddr. Also compute the minimum LMA of all non-empty + // sections as MinAddr. In the output, the contents between address 0 and + // MinAddr will be skipped. uint64_t MinAddr = UINT64_MAX; for (SectionBase &Sec : Obj.allocSections()) { if (Sec.ParentSegment != nullptr) Sec.Addr = Sec.Offset - Sec.ParentSegment->Offset + Sec.ParentSegment->PAddr; - MinAddr = std::min(MinAddr, Sec.Addr); + if (Sec.Size > 0) + MinAddr = std::min(MinAddr, Sec.Addr); } // Now that every section has been laid out we just need to compute the total // file size. This might not be the same as the offset returned by // layoutSections, because we want to truncate the last segment to the end of - // its last section, to match GNU objcopy's behaviour. + // its last non-empty section, to match GNU objcopy's behaviour. TotalSize = 0; - for (SectionBase &Sec : Obj.allocSections()) { - Sec.Offset = Sec.Addr - MinAddr; - if (Sec.Type != SHT_NOBITS) + for (SectionBase &Sec : Obj.allocSections()) + if (Sec.Type != SHT_NOBITS && Sec.Size > 0) { + Sec.Offset = Sec.Addr - MinAddr; TotalSize = std::max(TotalSize, Sec.Offset + Sec.Size); - } + } if (Error E = Buf.allocate(TotalSize)) return E; |