forked from OSchip/llvm-project
[llvm-readobj] - Simplify conditions used for printing segment mappings. NFCI.
This patch is a NFC refactoring. Currently the logic is overcomplicated, contains dead conditions and is very hard to read. This patch performs a very straightforward simplification. Probably it can be simplified and improved more, but we need to land test cases documenting/testing all the current functionality first. Differential revision: https://reviews.llvm.org/D78709
This commit is contained in:
Georgii Rymar
parent
0d54612164
commit
e4ba3ff359
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@ -882,10 +882,6 @@ private:
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std::string getSymbolSectionNdx(const ELFO *Obj, const Elf_Sym *Symbol,
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const Elf_Sym *FirstSym);
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void printDynamicRelocation(const ELFO *Obj, Elf_Rela R, bool IsRela);
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bool checkTLSSections(const Elf_Phdr &Phdr, const Elf_Shdr &Sec);
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bool checkoffsets(const Elf_Phdr &Phdr, const Elf_Shdr &Sec);
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bool checkVMA(const Elf_Phdr &Phdr, const Elf_Shdr &Sec);
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bool checkPTDynamic(const Elf_Phdr &Phdr, const Elf_Shdr &Sec);
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void printProgramHeaders(const ELFO *Obj);
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void printSectionMapping(const ELFO *Obj);
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void printGNUVersionSectionProlog(const ELFFile<ELFT> *Obj,
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@ -4022,63 +4018,76 @@ static inline std::string printPhdrFlags(unsigned Flag) {
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return Str;
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}
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// SHF_TLS sections are only in PT_TLS, PT_LOAD or PT_GNU_RELRO
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// PT_TLS must only have SHF_TLS sections
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template <class ELFT>
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bool GNUStyle<ELFT>::checkTLSSections(const Elf_Phdr &Phdr,
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const Elf_Shdr &Sec) {
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return (((Sec.sh_flags & ELF::SHF_TLS) &&
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((Phdr.p_type == ELF::PT_TLS) || (Phdr.p_type == ELF::PT_LOAD) ||
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(Phdr.p_type == ELF::PT_GNU_RELRO))) ||
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(!(Sec.sh_flags & ELF::SHF_TLS) && Phdr.p_type != ELF::PT_TLS));
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static bool checkTLSSections(const typename ELFT::Phdr &Phdr,
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const typename ELFT::Shdr &Sec) {
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if (Sec.sh_flags & ELF::SHF_TLS) {
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// .tbss must only be shown in the PT_TLS segment.
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if (Sec.sh_type == ELF::SHT_NOBITS)
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return Phdr.p_type == ELF::PT_TLS;
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// SHF_TLS sections are only shown in PT_TLS, PT_LOAD or PT_GNU_RELRO
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// segments.
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return (Phdr.p_type == ELF::PT_TLS) || (Phdr.p_type == ELF::PT_LOAD) ||
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(Phdr.p_type == ELF::PT_GNU_RELRO);
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}
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// PT_TLS must only have SHF_TLS sections.
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return Phdr.p_type != ELF::PT_TLS;
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}
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// Non-SHT_NOBITS must have its offset inside the segment
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// Only non-zero section can be at end of segment
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template <class ELFT>
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bool GNUStyle<ELFT>::checkoffsets(const Elf_Phdr &Phdr, const Elf_Shdr &Sec) {
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static bool checkOffsets(const typename ELFT::Phdr &Phdr,
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const typename ELFT::Shdr &Sec) {
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// SHT_NOBITS sections don't need to have an offset inside the segment.
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if (Sec.sh_type == ELF::SHT_NOBITS)
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return true;
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bool IsSpecial =
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(Sec.sh_type == ELF::SHT_NOBITS) && ((Sec.sh_flags & ELF::SHF_TLS) != 0);
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// .tbss is special, it only has memory in PT_TLS and has NOBITS properties
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auto SectionSize =
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(IsSpecial && Phdr.p_type != ELF::PT_TLS) ? 0 : Sec.sh_size;
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if (Sec.sh_offset >= Phdr.p_offset)
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return ((Sec.sh_offset + SectionSize <= Phdr.p_filesz + Phdr.p_offset)
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/*only non-zero sized sections at end*/
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&& (Sec.sh_offset + 1 <= Phdr.p_offset + Phdr.p_filesz));
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return false;
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if (Sec.sh_offset < Phdr.p_offset)
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return false;
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// Only non-empty sections can be at the end of a segment.
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if (Sec.sh_size == 0)
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return (Sec.sh_offset + 1 <= Phdr.p_offset + Phdr.p_filesz);
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return Sec.sh_offset + Sec.sh_size <= Phdr.p_offset + Phdr.p_filesz;
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}
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// SHF_ALLOC must have VMA inside segment
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// Only non-zero section can be at end of segment
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// Check that an allocatable section belongs to a virtual address
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// space of a segment.
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template <class ELFT>
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bool GNUStyle<ELFT>::checkVMA(const Elf_Phdr &Phdr, const Elf_Shdr &Sec) {
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static bool checkVMA(const typename ELFT::Phdr &Phdr,
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const typename ELFT::Shdr &Sec) {
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if (!(Sec.sh_flags & ELF::SHF_ALLOC))
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return true;
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bool IsSpecial =
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if (Sec.sh_addr < Phdr.p_vaddr)
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return false;
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bool IsTbss =
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(Sec.sh_type == ELF::SHT_NOBITS) && ((Sec.sh_flags & ELF::SHF_TLS) != 0);
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// .tbss is special, it only has memory in PT_TLS and has NOBITS properties
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auto SectionSize =
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(IsSpecial && Phdr.p_type != ELF::PT_TLS) ? 0 : Sec.sh_size;
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if (Sec.sh_addr >= Phdr.p_vaddr)
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return ((Sec.sh_addr + SectionSize <= Phdr.p_vaddr + Phdr.p_memsz) &&
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(Sec.sh_addr + 1 <= Phdr.p_vaddr + Phdr.p_memsz));
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return false;
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// .tbss is special, it only has memory in PT_TLS and has NOBITS properties.
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bool IsTbssInNonTLS = IsTbss && Phdr.p_type != ELF::PT_TLS;
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// Only non-empty sections can be at the end of a segment.
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if (Sec.sh_size == 0 || IsTbssInNonTLS)
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return Sec.sh_addr + 1 <= Phdr.p_vaddr + Phdr.p_memsz;
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return Sec.sh_addr + Sec.sh_size <= Phdr.p_vaddr + Phdr.p_memsz;
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}
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// No section with zero size must be at start or end of PT_DYNAMIC
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template <class ELFT>
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bool GNUStyle<ELFT>::checkPTDynamic(const Elf_Phdr &Phdr, const Elf_Shdr &Sec) {
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if (Phdr.p_type != ELF::PT_DYNAMIC || Sec.sh_size != 0 || Phdr.p_memsz == 0)
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static bool checkPTDynamic(const typename ELFT::Phdr &Phdr,
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const typename ELFT::Shdr &Sec) {
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if (Phdr.p_type != ELF::PT_DYNAMIC || Phdr.p_memsz == 0 || Sec.sh_size != 0)
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return true;
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// Is section within the phdr both based on offset and VMA ?
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return ((Sec.sh_type == ELF::SHT_NOBITS) ||
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(Sec.sh_offset > Phdr.p_offset &&
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Sec.sh_offset < Phdr.p_offset + Phdr.p_filesz)) &&
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(!(Sec.sh_flags & ELF::SHF_ALLOC) ||
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(Sec.sh_addr > Phdr.p_vaddr && Sec.sh_addr < Phdr.p_memsz));
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// We get here when we have an empty section. Only non-empty sections can be
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// at the start or at the end of PT_DYNAMIC.
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// Is section within the phdr both based on offset and VMA?
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bool CheckOffset = (Sec.sh_type == ELF::SHT_NOBITS) ||
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(Sec.sh_offset > Phdr.p_offset &&
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Sec.sh_offset < Phdr.p_offset + Phdr.p_filesz);
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bool CheckVA = !(Sec.sh_flags & ELF::SHF_ALLOC) ||
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(Sec.sh_addr > Phdr.p_vaddr && Sec.sh_addr < Phdr.p_memsz);
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return CheckOffset && CheckVA;
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}
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template <class ELFT>
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@ -4167,17 +4176,16 @@ void GNUStyle<ELFT>::printSectionMapping(const ELFO *Obj) {
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unwrapOrError(this->FileName, Obj->program_headers())) {
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std::string Sections;
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OS << format(" %2.2d ", Phnum++);
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// Check if each section is in a segment and then print mapping.
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for (const Elf_Shdr &Sec : unwrapOrError(this->FileName, Obj->sections())) {
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// Check if each section is in a segment and then print mapping.
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if (Sec.sh_type == ELF::SHT_NULL)
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continue;
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// readelf additionally makes sure it does not print zero sized sections
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// at end of segments and for PT_DYNAMIC both start and end of section
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// .tbss must only be shown in PT_TLS section.
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bool TbssInNonTLS = (Sec.sh_type == ELF::SHT_NOBITS) &&
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((Sec.sh_flags & ELF::SHF_TLS) != 0) &&
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Phdr.p_type != ELF::PT_TLS;
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if (!TbssInNonTLS && checkTLSSections(Phdr, Sec) &&
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checkoffsets(Phdr, Sec) && checkVMA(Phdr, Sec) &&
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checkPTDynamic(Phdr, Sec) && (Sec.sh_type != ELF::SHT_NULL)) {
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if (checkTLSSections<ELFT>(Phdr, Sec) && checkOffsets<ELFT>(Phdr, Sec) &&
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checkVMA<ELFT>(Phdr, Sec) && checkPTDynamic<ELFT>(Phdr, Sec)) {
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Sections +=
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unwrapOrError(this->FileName, Obj->getSectionName(&Sec)).str() +
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" ";
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