Author: labath Date: Sat Dec 15 05:45:38 2018 New Revision: 349268 URL: http://llvm.org/viewvc/llvm-project?rev=349268&view=rev Log: ELF: more section creation cleanup
Summary: This patch attempts to move as much code as possible out of the CreateSections function to make room for future improvements there. Some of this may be slightly over-engineered (VMAddressProvider), but I wanted to keep the logic of this function very simple, because once I start taking segment headers into acount (as discussed in D55356), the function is going to grow significantly. While in there, I also added tests for various bits of functionality. This should be NFC, except that I changed the order of hac^H^Heuristicks for determining section type slightly. Previously, name-based deduction (.symtab -> symtab) would take precedence over type-based (SHT_SYMTAB -> symtab) one. In fact we would assert if we ran into a .text section with type SHT_SYMTAB. Though unlikely to matter in practice, this order seemed wrong to me, so I have inverted it. Reviewers: clayborg, krytarowski, espindola Subscribers: emaste, arichardson, lldb-commits Differential Revision: https://reviews.llvm.org/D55706 Added: lldb/trunk/lit/Modules/ELF/section-addresses.yaml lldb/trunk/lit/Modules/ELF/section-permissions.yaml lldb/trunk/lit/Modules/ELF/section-types-edgecases.yaml Modified: lldb/trunk/lit/Modules/ELF/compressed-sections.yaml lldb/trunk/lit/Modules/ELF/section-types.yaml lldb/trunk/lit/Modules/MachO/subsections.yaml lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h lldb/trunk/tools/lldb-test/lldb-test.cpp Modified: lldb/trunk/lit/Modules/ELF/compressed-sections.yaml URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/ELF/compressed-sections.yaml?rev=349268&r1=349267&r2=349268&view=diff ============================================================================== --- lldb/trunk/lit/Modules/ELF/compressed-sections.yaml (original) +++ lldb/trunk/lit/Modules/ELF/compressed-sections.yaml Sat Dec 15 05:45:38 2018 @@ -19,15 +19,13 @@ Sections: # CHECK: Name: .hello_elf # CHECK-NEXT: Type: regular -# CHECK-NEXT: Thread specific: no -# CHECK-NEXT: VM size: 0 +# CHECK: VM size: 0 # CHECK-NEXT: File size: 28 # CHECK-NEXT: Data: # CHECK-NEXT: 20304050 60708090 # CHECK: Name: .bogus # CHECK-NEXT: Type: regular -# CHECK-NEXT: Thread specific: no -# CHECK-NEXT: VM size: 0 +# CHECK: VM size: 0 # CHECK-NEXT: File size: 8 # CHECK-NEXT: Data: () Added: lldb/trunk/lit/Modules/ELF/section-addresses.yaml URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/ELF/section-addresses.yaml?rev=349268&view=auto ============================================================================== --- lldb/trunk/lit/Modules/ELF/section-addresses.yaml (added) +++ lldb/trunk/lit/Modules/ELF/section-addresses.yaml Sat Dec 15 05:45:38 2018 @@ -0,0 +1,58 @@ +# RUN: yaml2obj %s > %t +# RUN: lldb-test object-file %t | FileCheck %s + +# CHECK-LABEL: Name: .one +# CHECK: VM address: 0x0 + +# CHECK-LABEL: Name: .nonalloc +# CHECK: VM address: 0x0 + +# CHECK-LABEL: Name: .two +# CHECK: VM address: 0x8 + +# CHECK-LABEL: Name: .three +# CHECK: VM address: 0xc + +# CHECK-LABEL: Name: .four +# CHECK: VM address: 0xc + +# CHECK-LABEL: Name: .five +# CHECK: VM address: 0x1000 + +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_REL + Machine: EM_X86_64 + Entry: 0x00000000000007A0 +Sections: + - Name: .one + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + AddressAlign: 0x0000000000000004 + Content: DEADBEEFBAADF00D + - Name: .nonalloc + Type: SHT_PROGBITS + AddressAlign: 0x0000000000000004 + Content: DEADBEEFBAADF00D + - Name: .two + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + AddressAlign: 0x0000000000000004 + Content: DE + - Name: .three + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + AddressAlign: 0x0000000000000004 + - Name: .four + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + AddressAlign: 0x0000000000000004 + Content: DEADBEEFBAADF00D + - Name: .five + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC ] + AddressAlign: 0x0000000000001000 + Content: DEADBEEFBAADF00D +... Added: lldb/trunk/lit/Modules/ELF/section-permissions.yaml URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/ELF/section-permissions.yaml?rev=349268&view=auto ============================================================================== --- lldb/trunk/lit/Modules/ELF/section-permissions.yaml (added) +++ lldb/trunk/lit/Modules/ELF/section-permissions.yaml Sat Dec 15 05:45:38 2018 @@ -0,0 +1,34 @@ +# RUN: yaml2obj %s > %t +# RUN: lldb-test object-file %t | FileCheck %s + +# CHECK-LABEL: Name: .r-x +# CHECK: Permissions: r-x +# +# CHECK-LABEL: Name: .rw- +# CHECK: Permissions: rw- + +# CHECK-LABEL: Name: .--- +# CHECK: Permissions: --- + +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_DYN + Machine: EM_X86_64 + Entry: 0x00000000000007A0 +Sections: + - Name: .r-x + Type: SHT_PROGBITS + Flags: [ SHF_ALLOC, SHF_EXECINSTR ] + Content: DEADBEEFBAADF00D + - Name: .rw- + Type: SHT_PROGBITS + Flags: [ SHF_WRITE, SHF_ALLOC ] + AddressAlign: 0x0000000000000004 + Content: DEADBEEFBAADF00D + - Name: .--- + Type: SHT_PROGBITS + AddressAlign: 0x0000000000000001 + Content: DEADBEEFBAADF00D +... Added: lldb/trunk/lit/Modules/ELF/section-types-edgecases.yaml URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/ELF/section-types-edgecases.yaml?rev=349268&view=auto ============================================================================== --- lldb/trunk/lit/Modules/ELF/section-types-edgecases.yaml (added) +++ lldb/trunk/lit/Modules/ELF/section-types-edgecases.yaml Sat Dec 15 05:45:38 2018 @@ -0,0 +1,35 @@ +# This test doesn't attempt to mandate a specific section classification. It is +# here to document the existing behavior and to make sure we don't do something +# completely crazy (like crashing). + +# RUN: yaml2obj %s > %t +# RUN: lldb-test object-file %t | FileCheck %s + +# The section is called .data, but it has the SHF_EXECINSTR flag set. Have +# the flag take precedence over the name. +# CHECK-LABEL: Name: .data +# CHECK-NEXT: Type: code + +# Section type (SHT_SYMTAB) takes precedence over name-based deduction. +# CHECK-LABEL: Name: .text +# CHECK-NEXT: Type: elf-symbol-table + +--- !ELF +FileHeader: + Class: ELFCLASS64 + Data: ELFDATA2LSB + Type: ET_DYN + Machine: EM_X86_64 + Entry: 0x00000000000007A0 +Sections: + - Name: .data + Type: SHT_PROGBITS + Flags: [ SHF_EXECINSTR, SHF_ALLOC ] + AddressAlign: 0x0000000000000004 + Content: DEADBEEFBAADF00D + - Name: .text + Type: SHT_SYMTAB + Flags: [ ] + AddressAlign: 0x0000000000000004 + Content: DEADBEEFBAADF00D +... Modified: lldb/trunk/lit/Modules/ELF/section-types.yaml URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/ELF/section-types.yaml?rev=349268&r1=349267&r2=349268&view=diff ============================================================================== --- lldb/trunk/lit/Modules/ELF/section-types.yaml (original) +++ lldb/trunk/lit/Modules/ELF/section-types.yaml Sat Dec 15 05:45:38 2018 @@ -25,11 +25,11 @@ # CHECK-LABEL: Name: .tdata # CHECK-NEXT: Type: data -# CHECK-NEXT: Thread specific: yes +# CHECK: Thread specific: yes # CHECK-LABEL: Name: .tbss # CHECK-NEXT: Type: zero-fill -# CHECK-NEXT: Thread specific: yes +# CHECK: Thread specific: yes --- !ELF FileHeader: Modified: lldb/trunk/lit/Modules/MachO/subsections.yaml URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/MachO/subsections.yaml?rev=349268&r1=349267&r2=349268&view=diff ============================================================================== --- lldb/trunk/lit/Modules/MachO/subsections.yaml (original) +++ lldb/trunk/lit/Modules/MachO/subsections.yaml Sat Dec 15 05:45:38 2018 @@ -5,7 +5,9 @@ #CHECK-NEXT: Index: 0 #CHECK-NEXT: Name: __PAGEZERO #CHECK-NEXT: Type: container +#CHECK-NEXT: Permissions: --- #CHECK-NEXT: Thread specific: no +#CHECK-NEXT: VM address: 0x0 #CHECK-NEXT: VM size: 4294967296 #CHECK-NEXT: File size: 0 #CHECK-NEXT: There are no subsections @@ -13,28 +15,36 @@ #CHECK: Index: 1 #CHECK-NEXT: Name: __TEXT #CHECK-NEXT: Type: container +#CHECK-NEXT: Permissions: r-x #CHECK-NEXT: Thread specific: no +#CHECK-NEXT: VM address: 0x100000000 #CHECK-NEXT: VM size: 4096 #CHECK-NEXT: File size: 4096 #CHECK-NEXT: Showing 3 subsections #CHECK-NEXT: Index: 0 #CHECK-NEXT: Name: __text #CHECK-NEXT: Type: code +#CHECK-NEXT: Permissions: r-x #CHECK-NEXT: Thread specific: no +#CHECK-NEXT: VM address: 0x100000f30 #CHECK-NEXT: VM size: 22 #CHECK-NEXT: File size: 22 # #CHECK: Index: 1 #CHECK-NEXT: Name: __unwind_info #CHECK-NEXT: Type: compact-unwind +#CHECK-NEXT: Permissions: r-x #CHECK-NEXT: Thread specific: no +#CHECK-NEXT: VM address: 0x100000f48 #CHECK-NEXT: VM size: 76 #CHECK-NEXT: File size: 76 # #CHECK: Index: 2 #CHECK-NEXT: Name: __eh_frame #CHECK-NEXT: Type: eh-frame +#CHECK-NEXT: Permissions: r-x #CHECK-NEXT: Thread specific: no +#CHECK-NEXT: VM address: 0x100000f98 #CHECK-NEXT: VM size: 104 #CHECK-NEXT: File size: 104 Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp?rev=349268&r1=349267&r2=349268&view=diff ============================================================================== --- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp (original) +++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp Sat Dec 15 05:45:38 2018 @@ -1735,7 +1735,7 @@ lldb::user_id_t ObjectFileELF::GetSectio return 0; } -static SectionType getSectionType(llvm::StringRef Name) { +static SectionType GetSectionTypeFromName(llvm::StringRef Name) { return llvm::StringSwitch<SectionType>(Name) .Case(".ARM.exidx", eSectionTypeARMexidx) .Case(".ARM.extab", eSectionTypeARMextab) @@ -1774,16 +1774,85 @@ static SectionType getSectionType(llvm:: .Default(eSectionTypeOther); } +SectionType ObjectFileELF::GetSectionType(const ELFSectionHeaderInfo &H) const { + switch (H.sh_type) { + case SHT_PROGBITS: + if (H.sh_flags & SHF_EXECINSTR) + return eSectionTypeCode; + break; + case SHT_SYMTAB: + return eSectionTypeELFSymbolTable; + case SHT_DYNSYM: + return eSectionTypeELFDynamicSymbols; + case SHT_RELA: + case SHT_REL: + return eSectionTypeELFRelocationEntries; + case SHT_DYNAMIC: + return eSectionTypeELFDynamicLinkInfo; + } + SectionType Type = GetSectionTypeFromName(H.section_name.GetStringRef()); + if (Type == eSectionTypeOther) { + // the kalimba toolchain assumes that ELF section names are free-form. + // It does support linkscripts which (can) give rise to various + // arbitrarily named sections being "Code" or "Data". + Type = kalimbaSectionType(m_header, H); + } + return Type; +} + +static uint32_t GetTargetByteSize(SectionType Type, const ArchSpec &arch) { + switch (Type) { + case eSectionTypeData: + case eSectionTypeZeroFill: + return arch.GetDataByteSize(); + case eSectionTypeCode: + return arch.GetCodeByteSize(); + default: + return 1; + } +} + +static Permissions GetPermissions(const ELFSectionHeader &H) { + Permissions Perm = Permissions(0); + if (H.sh_flags & SHF_ALLOC) + Perm |= ePermissionsReadable; + if (H.sh_flags & SHF_WRITE) + Perm |= ePermissionsWritable; + if (H.sh_flags & SHF_EXECINSTR) + Perm |= ePermissionsExecutable; + return Perm; +} + +namespace { +// (Unlinked) ELF object files usually have 0 for every section address, meaning +// we need to compute synthetic addresses in order for "file addresses" from +// different sections to not overlap. This class handles that logic. +class VMAddressProvider { + bool m_synthesizing; + addr_t m_next; + +public: + VMAddressProvider(ObjectFile::Type Type) + : m_synthesizing(Type == ObjectFile::Type::eTypeObjectFile), m_next(0) {} + + std::pair<addr_t, addr_t> GetAddressAndSize(const ELFSectionHeader &H) { + addr_t address = H.sh_addr; + addr_t size = H.sh_flags & SHF_ALLOC ? H.sh_size : 0; + if (m_synthesizing && (H.sh_flags & SHF_ALLOC)) { + m_next = llvm::alignTo(m_next, std::max<addr_t>(H.sh_addralign, 1)); + address = m_next; + m_next += size; + } + return {address, size}; + } +}; +} + void ObjectFileELF::CreateSections(SectionList &unified_section_list) { if (!m_sections_ap.get() && ParseSectionHeaders()) { m_sections_ap.reset(new SectionList()); - // Object files frequently have 0 for every section address, meaning we - // need to compute synthetic addresses in order for "file addresses" from - // different sections to not overlap - bool synthaddrs = (CalculateType() == ObjectFile::Type::eTypeObjectFile); - uint64_t nextaddr = 0; - + VMAddressProvider address_provider(CalculateType()); for (SectionHeaderCollIter I = m_section_headers.begin(); I != m_section_headers.end(); ++I) { const ELFSectionHeaderInfo &header = *I; @@ -1791,69 +1860,18 @@ void ObjectFileELF::CreateSections(Secti ConstString &name = I->section_name; const uint64_t file_size = header.sh_type == SHT_NOBITS ? 0 : header.sh_size; - const uint64_t vm_size = header.sh_flags & SHF_ALLOC ? header.sh_size : 0; - SectionType sect_type = getSectionType(name.GetStringRef()); + addr_t vm_addr, vm_size; + std::tie(vm_addr, vm_size) = address_provider.GetAddressAndSize(header); - bool is_thread_specific = header.sh_flags & SHF_TLS; - const uint32_t permissions = - ((header.sh_flags & SHF_ALLOC) ? ePermissionsReadable : 0u) | - ((header.sh_flags & SHF_WRITE) ? ePermissionsWritable : 0u) | - ((header.sh_flags & SHF_EXECINSTR) ? ePermissionsExecutable : 0u); - switch (header.sh_type) { - case SHT_SYMTAB: - assert(sect_type == eSectionTypeOther); - sect_type = eSectionTypeELFSymbolTable; - break; - case SHT_DYNSYM: - assert(sect_type == eSectionTypeOther); - sect_type = eSectionTypeELFDynamicSymbols; - break; - case SHT_RELA: - case SHT_REL: - assert(sect_type == eSectionTypeOther); - sect_type = eSectionTypeELFRelocationEntries; - break; - case SHT_DYNAMIC: - assert(sect_type == eSectionTypeOther); - sect_type = eSectionTypeELFDynamicLinkInfo; - break; - } - - if (eSectionTypeOther == sect_type) { - // the kalimba toolchain assumes that ELF section names are free-form. - // It does support linkscripts which (can) give rise to various - // arbitrarily named sections being "Code" or "Data". - sect_type = kalimbaSectionType(m_header, header); - } - - // In common case ELF code section can have arbitrary name (for example, - // we can specify it using section attribute for particular function) so - // assume that section is a code section if it has SHF_EXECINSTR flag set - // and has SHT_PROGBITS type. - if (eSectionTypeOther == sect_type && - llvm::ELF::SHT_PROGBITS == header.sh_type && - (header.sh_flags & SHF_EXECINSTR)) { - sect_type = eSectionTypeCode; - } + SectionType sect_type = GetSectionType(header); const uint32_t target_bytes_size = - (eSectionTypeData == sect_type || eSectionTypeZeroFill == sect_type) - ? m_arch_spec.GetDataByteSize() - : eSectionTypeCode == sect_type ? m_arch_spec.GetCodeByteSize() - : 1; + GetTargetByteSize(sect_type, m_arch_spec); + elf::elf_xword log2align = (header.sh_addralign == 0) ? 0 : llvm::Log2_64(header.sh_addralign); - uint64_t addr = header.sh_addr; - - if ((header.sh_flags & SHF_ALLOC) && synthaddrs) { - nextaddr = - (nextaddr + header.sh_addralign - 1) & ~(header.sh_addralign - 1); - addr = nextaddr; - nextaddr += vm_size; - } - SectionSP section_sp(new Section( GetModule(), // Module to which this section belongs. this, // ObjectFile to which this section belongs and should read @@ -1861,7 +1879,7 @@ void ObjectFileELF::CreateSections(Secti SectionIndex(I), // Section ID. name, // Section name. sect_type, // Section type. - addr, // VM address. + vm_addr, // VM address. vm_size, // VM size in bytes of this section. header.sh_offset, // Offset of this section in the file. file_size, // Size of the section as found in the file. @@ -1869,9 +1887,8 @@ void ObjectFileELF::CreateSections(Secti header.sh_flags, // Flags for this section. target_bytes_size)); // Number of host bytes per target byte - section_sp->SetPermissions(permissions); - if (is_thread_specific) - section_sp->SetIsThreadSpecific(is_thread_specific); + section_sp->SetPermissions(GetPermissions(header)); + section_sp->SetIsThreadSpecific(header.sh_flags & SHF_TLS); m_sections_ap->AddSection(section_sp); } } Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h?rev=349268&r1=349267&r2=349268&view=diff ============================================================================== --- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h (original) +++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h Sat Dec 15 05:45:38 2018 @@ -246,6 +246,8 @@ private: /// Returns the number of headers parsed. size_t ParseSectionHeaders(); + lldb::SectionType GetSectionType(const ELFSectionHeaderInfo &H) const; + static void ParseARMAttributes(lldb_private::DataExtractor &data, uint64_t length, lldb_private::ArchSpec &arch_spec); Modified: lldb/trunk/tools/lldb-test/lldb-test.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/tools/lldb-test/lldb-test.cpp?rev=349268&r1=349267&r2=349268&view=diff ============================================================================== --- lldb/trunk/tools/lldb-test/lldb-test.cpp (original) +++ lldb/trunk/tools/lldb-test/lldb-test.cpp Sat Dec 15 05:45:38 2018 @@ -30,6 +30,7 @@ #include "lldb/Target/Target.h" #include "lldb/Utility/CleanUp.h" #include "lldb/Utility/DataExtractor.h" +#include "lldb/Utility/State.h" #include "lldb/Utility/StreamString.h" #include "llvm/ADT/IntervalMap.h" @@ -733,7 +734,9 @@ static void dumpSectionList(LinePrinter Printer.formatLine("Index: {0}", I); Printer.formatLine("Name: {0}", S->GetName().GetStringRef()); Printer.formatLine("Type: {0}", S->GetTypeAsCString()); + Printer.formatLine("Permissions: {0}", GetPermissionsAsCString(S->GetPermissions())); Printer.formatLine("Thread specific: {0:y}", S->IsThreadSpecific()); + Printer.formatLine("VM address: {0:x}", S->GetFileAddress()); Printer.formatLine("VM size: {0}", S->GetByteSize()); Printer.formatLine("File size: {0}", S->GetFileSize()); _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
