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lld/ELF/DWARF.cpp
| Show All 20 Lines | |||||
| #include "llvm/Object/ELFObjectFile.h" | #include "llvm/Object/ELFObjectFile.h" | ||||
| using namespace llvm; | using namespace llvm; | ||||
| using namespace llvm::object; | using namespace llvm::object; | ||||
| using namespace lld; | using namespace lld; | ||||
| using namespace lld::elf; | using namespace lld::elf; | ||||
| template <class ELFT> LLDDwarfObj<ELFT>::LLDDwarfObj(ObjFile<ELFT> *obj) { | template <class ELFT> LLDDwarfObj<ELFT>::LLDDwarfObj(ObjFile<ELFT> *obj) { | ||||
| for (InputSectionBase *sec : obj->getSections()) { | ArrayRef<typename ELFT::Shdr> objSections = | ||||
| CHECK(obj->getObj().sections(), obj); | |||||
| for (auto it : llvm::enumerate(obj->getSections())) { | |||||
| InputSectionBase *sec = it.value(); | |||||
| if (!sec) | if (!sec) | ||||
grimar: So, you need this to read the flags from the `sh_flags` field of a section header in the… | |||||
| continue; | continue; | ||||
| // In DWARF v5, a .debug_info in a COMDAT group may represent a type unit. | |||||
| // Don't bother calling data() (which may uncompress the content) on it. | |||||
| if (LLDDWARFSection *m = | if (LLDDWARFSection *m = | ||||
| StringSwitch<LLDDWARFSection *>(sec->name) | StringSwitch<LLDDWARFSection *>(sec->name) | ||||
| .Case(".debug_addr", &addrSection) | .Case(".debug_addr", &addrSection) | ||||
| .Case(".debug_gnu_pubnames", &gnuPubnamesSection) | .Case(".debug_gnu_pubnames", &gnuPubnamesSection) | ||||
| .Case(".debug_gnu_pubtypes", &gnuPubtypesSection) | .Case(".debug_gnu_pubtypes", &gnuPubtypesSection) | ||||
| .Case(".debug_info", &infoSection) | |||||
| .Case(".debug_loclists", &loclistsSection) | .Case(".debug_loclists", &loclistsSection) | ||||
| .Case(".debug_ranges", &rangesSection) | .Case(".debug_ranges", &rangesSection) | ||||
| .Case(".debug_rnglists", &rnglistsSection) | .Case(".debug_rnglists", &rnglistsSection) | ||||
| .Case(".debug_str_offsets", &strOffsetsSection) | .Case(".debug_str_offsets", &strOffsetsSection) | ||||
| .Case(".debug_line", &lineSection) | .Case(".debug_line", &lineSection) | ||||
| .Default(nullptr)) { | .Default(nullptr)) { | ||||
| m->Data = toStringRef(sec->data()); | m->Data = toStringRef(sec->data()); | ||||
| m->sec = sec; | m->sec = sec; | ||||
| continue; | continue; | ||||
| } | } | ||||
| if (sec->name == ".debug_abbrev") | if (sec->name == ".debug_abbrev") | ||||
| abbrevSection = toStringRef(sec->data()); | abbrevSection = toStringRef(sec->data()); | ||||
| else if (sec->name == ".debug_str") | else if (sec->name == ".debug_str") | ||||
| strSection = toStringRef(sec->data()); | strSection = toStringRef(sec->data()); | ||||
| else if (sec->name == ".debug_line_str") | else if (sec->name == ".debug_line_str") | ||||
| lineStrSection = toStringRef(sec->data()); | lineStrSection = toStringRef(sec->data()); | ||||
| else if (sec->name == ".debug_info" && | |||||
| !(objSections[it.index()].sh_flags & ELF::SHF_GROUP)) { | |||||
| // In DWARF v5, -fdebug-types-section places type units in .debug_info | |||||
| // sections in COMDAT groups. They are not compile units and thus should | |||||
| // be ignored. If we place compile units in COMDAT groups in the future, | |||||
| // we will need to perform a lightweight parsing. We drop the SHF_GROUP | |||||
| // flag when the InputSection was created, so we need to retrieve sh_flags | |||||
| // from the ELF section header. | |||||
| infoSection.Data = toStringRef(sec->data()); | |||||
| infoSection.sec = sec; | |||||
| } | |||||
| } | } | ||||
| } | } | ||||
| namespace { | namespace { | ||||
| template <class RelTy> struct LLDRelocationResolver { | template <class RelTy> struct LLDRelocationResolver { | ||||
| // In the ELF ABIs, S sepresents the value of the symbol in the relocation | // In the ELF ABIs, S sepresents the value of the symbol in the relocation | ||||
| // entry. For Rela, the addend is stored as part of the relocation entry. | // entry. For Rela, the addend is stored as part of the relocation entry. | ||||
| static uint64_t resolve(object::RelocationRef ref, uint64_t s, | static uint64_t resolve(object::RelocationRef ref, uint64_t s, | ||||
| ▲ Show 20 Lines • Show All 62 Lines • Show Last 20 Lines | |||||
So, you need this to read the flags from the sh_flags field of a section header in the initial object.
And you can't just use sec->flags, because we drop the SHF_GROUP flag much earlier.
I do not know a simpler way to access initial flags. Though probably it worth adding an assert to check that the number
of sections in obj->getObj().sections() == the number of them in obj->getSections() and a comment
about SHT_GROUP flag? That way we will not forget to simplify this loop back later when will stop relying on SHF_GROUP flag.