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ELF: Simplfiy ELFFile::createAtom. 

createAtom function did too much in a single for-loop. This patch
splits the for-loop and extract COMDAT handling into a separate
function.

llvm-svn: 234276
This commit is contained in:
Rui Ueyama 2015-04-07 01:56:07 +00:00
parent aecab7a93d
commit f122b91a02
1 changed files with 56 additions and 56 deletions
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112
lld/lib/ReaderWriter/ELF/ELFFile.h
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@ -254,12 +254,10 @@ protected:
llvm::StringMap<std::vector<ELFDefinedAtom<ELFT> *>> &atomsForSection,
const Elf_Shdr *shdr);
// Handle Section groups/COMDAT scetions.
// Handle COMDAT scetions.
std::error_code handleSectionGroup(
StringRef signature, StringRef groupSectionName,
llvm::StringMap<std::vector<ELFDefinedAtom<ELFT> *>> &atomsForSection,
llvm::DenseMap<const Elf_Shdr *, std::vector<StringRef>> &comdatSections,
const Elf_Shdr *shdr);
const Elf_Shdr *section,
llvm::StringMap<std::vector<ELFDefinedAtom<ELFT> *>> &atomsForSection);
/// Process the Undefined symbol and create an atom for it.
ELFUndefinedAtom<ELFT> *createUndefinedAtom(StringRef symName,
@ -674,12 +672,9 @@ template <class ELFT> std::error_code ELFFile<ELFT>::createAtoms() {
// group sections have a mapping of the section header to the
// signature/section.
llvm::DenseMap<const Elf_Shdr *, std::pair<StringRef, StringRef>>
groupSections;
llvm::DenseMap<const Elf_Shdr *, StringRef> linkOnceSections;
// Contains a list of comdat sections for a group.
llvm::DenseMap<const Elf_Shdr *, std::vector<StringRef>> comdatSections;
for (auto &i : _sectionSymbols) {
const Elf_Shdr *section = i.first;
std::vector<Elf_Sym_Iter> &symbols = i.second;
@ -698,36 +693,11 @@ template <class ELFT> std::error_code ELFFile<ELFT>::createAtoms() {
if (std::error_code ec = sectionContents.getError())
return ec;
bool addAtoms = true;
// A section of type SHT_GROUP defines a grouping of sections. The
// name of a symbol from one of the containing object's symbol tables
// provides a signature for the section group. The section header of
// the SHT_GROUP section specifies the identifying symbol entry, as
// described: the sh_link member contains the section header index of
// the symbol table section that contains the entry. The sh_info
// member contains the symbol table index of the identifying entry.
// The sh_flags member of the section header contains 0. The name of
// the section (sh_name) is not specified.
if (isGroupSection(section)) {
const Elf_Word *groupMembers =
reinterpret_cast<const Elf_Word *>(sectionContents->data());
const long count = (section->sh_size) / sizeof(Elf_Word);
for (int i = 1; i < count; i++) {
const Elf_Shdr *sHdr = _objFile->getSection(groupMembers[i]);
ErrorOr<StringRef> sectionName = _objFile->getSectionName(sHdr);
if (std::error_code ec = sectionName.getError())
return ec;
comdatSections[section].push_back(*sectionName);
}
const Elf_Sym *symbol = _objFile->getSymbol(section->sh_info);
const Elf_Shdr *symtab = _objFile->getSection(section->sh_link);
ErrorOr<StringRef> symbolName = _objFile->getSymbolName(symtab, symbol);
if (std::error_code ec = symbolName.getError())
return ec;
groupSections.insert({section, {*symbolName, *sectionName}});
// SHT_GROUP sections are handled in the following loop.
if (isGroupSection(section))
continue;
}
bool addAtoms = true;
if (isGnuLinkOnceSection(*sectionName)) {
linkOnceSections.insert({section, *sectionName});
@ -858,13 +828,10 @@ template <class ELFT> std::error_code ELFFile<ELFT>::createAtoms() {
}
}
// Iterate over all the group sections to create parent atoms pointing to
// group-child atoms.
for (auto &sect : groupSections) {
StringRef signature = sect.second.first;
StringRef groupSectionName = sect.second.second;
handleSectionGroup(signature, groupSectionName, atomsForSection,
comdatSections, sect.first);
for (auto &i : _sectionSymbols) {
const Elf_Shdr *section = i.first;
if (std::error_code ec = handleSectionGroup(section, atomsForSection))
return ec;
}
for (auto &sect : linkOnceSections)
@ -903,27 +870,60 @@ std::error_code ELFFile<ELFT>::handleGnuLinkOnceSection(
template <class ELFT>
std::error_code ELFFile<ELFT>::handleSectionGroup(
StringRef signature, StringRef groupSectionName,
llvm::StringMap<std::vector<ELFDefinedAtom<ELFT> *>> &atomsForSection,
llvm::DenseMap<const Elf_Shdr *, std::vector<StringRef>> &comdatSections,
const Elf_Shdr *shdr) {
// TODO: Check for errors.
const Elf_Shdr *section,
llvm::StringMap<std::vector<ELFDefinedAtom<ELFT> *>> &atomsForSection) {
ErrorOr<StringRef> sectionName = this->getSectionName(section);
if (std::error_code ec = sectionName.getError())
return ec;
if (!isGroupSection(section))
return std::error_code();
auto sectionContents = getSectionContents(section);
if (std::error_code ec = sectionContents.getError())
return ec;
// A section of type SHT_GROUP defines a grouping of sections. The
// name of a symbol from one of the containing object's symbol tables
// provides a signature for the section group. The section header of
// the SHT_GROUP section specifies the identifying symbol entry, as
// described: the sh_link member contains the section header index of
// the symbol table section that contains the entry. The sh_info
// member contains the symbol table index of the identifying entry.
// The sh_flags member of the section header contains 0. The name of
// the section (sh_name) is not specified.
std::vector<StringRef> sectionNames;
const Elf_Word *groupMembers =
reinterpret_cast<const Elf_Word *>(sectionContents->data());
const size_t count = section->sh_size / sizeof(Elf_Word);
for (size_t i = 1; i < count; i++) {
const Elf_Shdr *shdr = _objFile->getSection(groupMembers[i]);
ErrorOr<StringRef> sectionName = _objFile->getSectionName(shdr);
if (std::error_code ec = sectionName.getError())
return ec;
sectionNames.push_back(*sectionName);
}
const Elf_Sym *symbol = _objFile->getSymbol(section->sh_info);
const Elf_Shdr *symtab = _objFile->getSection(section->sh_link);
ErrorOr<StringRef> symbolName = _objFile->getSymbolName(symtab, symbol);
if (std::error_code ec = symbolName.getError())
return ec;
unsigned int referenceStart = _references.size();
std::vector<ELFReference<ELFT> *> refs;
auto sectionNamesInGroup = comdatSections[shdr];
for (auto sectionName : sectionNamesInGroup) {
for (auto ha : atomsForSection[sectionName]) {
_groupChild[ha->symbol()] = std::make_pair(signature, shdr);
for (auto name : sectionNames) {
for (auto ha : atomsForSection[name]) {
_groupChild[ha->symbol()] = std::make_pair(*symbolName, section);
ELFReference<ELFT> *ref = new (_readerStorage)
ELFReference<ELFT>(lld::Reference::kindGroupChild);
ref->setTarget(ha);
refs.push_back(ref);
}
atomsForSection[sectionName].clear();
atomsForSection[name].clear();
}
// Create a gnu linkonce atom.
// Create an atom for comdat signature.
ELFDefinedAtom<ELFT> *atom = createDefinedAtom(
signature, groupSectionName, nullptr, shdr, ArrayRef<uint8_t>(),
*symbolName, *sectionName, nullptr, section, ArrayRef<uint8_t>(),
referenceStart, _references.size(), _references);
atom->setOrdinal(++_ordinal);
_definedAtoms._atoms.push_back(atom);