[llvm] r317646 - Reapply: Allow yaml2obj to order implicit sections for ELF
Rafael Avila de Espindola via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 7 17:20:13 PST 2017
Sorry, the test still fails, but it is not a crash, it is lld producing
a different error message.
This shows that yaml2obj is producing a different output on that input
now. Is that intentional?
Cheers,
Rafael
Rafael Avila de Espindola <rafael.espindola at gmail.com> writes:
> The same test still crashes.
>
>
> Dave Lee via llvm-commits <llvm-commits at lists.llvm.org> writes:
>
>> Author: kastiglione
>> Date: Tue Nov 7 16:58:50 2017
>> New Revision: 317646
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=317646&view=rev
>> Log:
>> Reapply: Allow yaml2obj to order implicit sections for ELF
>>
>> Summary:
>> This change allows yaml input to control the order of implicitly added sections
>> (`.symtab`, `.strtab`, `.shstrtab`). The order is controlled by adding a
>> placeholder section of the given name to the Sections field.
>>
>> This change is to support changes in D39582, where it is desirable to control
>> the location of the `.dynsym` section.
>>
>> This reapplied version fixes:
>> 1. use of a function call within an assert
>> 2. failing lld test which has an unnamed section
>>
>> Additionally, one more test to cover the unnamed section failure.
>>
>> Reviewers: compnerd, jakehehrlich
>>
>> Reviewed By: jakehehrlich
>>
>> Subscribers: llvm-commits
>>
>> Differential Revision: https://reviews.llvm.org/D39749
>>
>> Added:
>> llvm/trunk/test/tools/yaml2obj/section-ordering.yaml
>> llvm/trunk/test/tools/yaml2obj/unnamed-section.yaml
>> Modified:
>> llvm/trunk/lib/ObjectYAML/ELFYAML.cpp
>> llvm/trunk/tools/yaml2obj/yaml2elf.cpp
>>
>> Modified: llvm/trunk/lib/ObjectYAML/ELFYAML.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ObjectYAML/ELFYAML.cpp?rev=317646&r1=317645&r2=317646&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/ObjectYAML/ELFYAML.cpp (original)
>> +++ llvm/trunk/lib/ObjectYAML/ELFYAML.cpp Tue Nov 7 16:58:50 2017
>> @@ -388,7 +388,7 @@ void ScalarEnumerationTraits<ELFYAML::EL
>> #define ECase(X) IO.enumCase(Value, #X, ELF::X)
>> ECase(SHT_NULL);
>> ECase(SHT_PROGBITS);
>> - // No SHT_SYMTAB. Use the top-level `Symbols` key instead.
>> + ECase(SHT_SYMTAB);
>> // FIXME: Issue a diagnostic with this information.
>> ECase(SHT_STRTAB);
>> ECase(SHT_RELA);
>>
>> Added: llvm/trunk/test/tools/yaml2obj/section-ordering.yaml
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/yaml2obj/section-ordering.yaml?rev=317646&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/tools/yaml2obj/section-ordering.yaml (added)
>> +++ llvm/trunk/test/tools/yaml2obj/section-ordering.yaml Tue Nov 7 16:58:50 2017
>> @@ -0,0 +1,29 @@
>> +# Ensures that implicitly added sections can be ordered within Sections.
>> +# RUN: yaml2obj %s -o %t
>> +# RUN: llvm-readobj -sections %t | FileCheck %s
>> +
>> +!ELF
>> +FileHeader:
>> + Class: ELFCLASS64
>> + Data: ELFDATA2LSB
>> + Type: ET_EXEC
>> + Machine: EM_X86_64
>> +Sections:
>> + - Name: .text
>> + Type: SHT_PROGBITS
>> + Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
>> + - Name: .symtab
>> + Type: SHT_SYMTAB
>> + - Name: .data
>> + Type: SHT_PROGBITS
>> + Flags: [ SHF_ALLOC, SHF_WRITE ]
>> + - Name: .shstrtab
>> + Type: SHT_STRTAB
>> + - Name: .strtab
>> + Type: SHT_STRTAB
>> +
>> +# CHECK: Name: .text
>> +# CHECK: Name: .symtab
>> +# CHECK: Name: .data
>> +# CHECK: Name: .shstrtab
>> +# CHECK: Name: .strtab
>>
>> Added: llvm/trunk/test/tools/yaml2obj/unnamed-section.yaml
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/yaml2obj/unnamed-section.yaml?rev=317646&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/tools/yaml2obj/unnamed-section.yaml (added)
>> +++ llvm/trunk/test/tools/yaml2obj/unnamed-section.yaml Tue Nov 7 16:58:50 2017
>> @@ -0,0 +1,14 @@
>> +# Ensure yaml2obj doesn't crash on unnamed sections
>> +# RUN: yaml2obj %s
>> +
>> +!ELF
>> +FileHeader:
>> + Class: ELFCLASS64
>> + Data: ELFDATA2LSB
>> + Type: ET_EXEC
>> + Machine: EM_X86_64
>> +Sections:
>> + - Type: SHT_PROGBITS
>> + - Name: .text
>> + Type: SHT_PROGBITS
>> + Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
>>
>> Modified: llvm/trunk/tools/yaml2obj/yaml2elf.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/yaml2obj/yaml2elf.cpp?rev=317646&r1=317645&r2=317646&view=diff
>> ==============================================================================
>> --- llvm/trunk/tools/yaml2obj/yaml2elf.cpp (original)
>> +++ llvm/trunk/tools/yaml2obj/yaml2elf.cpp Tue Nov 7 16:58:50 2017
>> @@ -74,6 +74,14 @@ public:
>> Idx = I->getValue();
>> return false;
>> }
>> + /// asserts if name is not present in the map
>> + unsigned get(StringRef Name) const {
>> + unsigned Idx = 0;
>> + auto missing = lookup(Name, Idx);
>> + assert(!missing && "Expected section not found in index");
>> + return Idx;
>> + }
>> + unsigned size() const { return Map.size(); }
>> };
>> } // end anonymous namespace
>>
>> @@ -144,19 +152,21 @@ class ELFState {
>> ContiguousBlobAccumulator &CBA);
>>
>> // - SHT_NULL entry (placed first, i.e. 0'th entry)
>> - // - symbol table (.symtab) (placed third to last)
>> - // - string table (.strtab) (placed second to last)
>> - // - section header string table (.shstrtab) (placed last)
>> - unsigned getDotSymTabSecNo() const { return Doc.Sections.size() + 1; }
>> - unsigned getDotStrTabSecNo() const { return Doc.Sections.size() + 2; }
>> - unsigned getDotShStrTabSecNo() const { return Doc.Sections.size() + 3; }
>> - unsigned getSectionCount() const { return Doc.Sections.size() + 4; }
>> + // - symbol table (.symtab) (defaults to third to last)
>> + // - string table (.strtab) (defaults to second to last)
>> + // - section header string table (.shstrtab) (defaults to last)
>> + unsigned getDotSymTabSecNo() const { return SN2I.get(".symtab"); }
>> + unsigned getDotStrTabSecNo() const { return SN2I.get(".strtab"); }
>> + unsigned getDotShStrTabSecNo() const { return SN2I.get(".shstrtab"); }
>> + unsigned getSectionCount() const { return SN2I.size() + 1; }
>>
>> ELFState(const ELFYAML::Object &D) : Doc(D) {}
>>
>> public:
>> static int writeELF(raw_ostream &OS, const ELFYAML::Object &Doc);
>> };
>> +
>> +static const char * const ImplicitSecNames[] = {".symtab", ".strtab", ".shstrtab"};
>> } // end anonymous namespace
>>
>> template <class ELFT>
>> @@ -211,10 +221,6 @@ bool ELFState<ELFT>::initSectionHeaders(
>> zero(SHeader);
>> SHeaders.push_back(SHeader);
>>
>> - for (const auto &Sec : Doc.Sections)
>> - DotShStrtab.add(Sec->Name);
>> - DotShStrtab.finalize();
>> -
>> for (const auto &Sec : Doc.Sections) {
>> zero(SHeader);
>> SHeader.sh_name = DotShStrtab.getOffset(Sec->Name);
>> @@ -547,12 +553,9 @@ bool ELFState<ELFT>::writeSectionContent
>> }
>>
>> template <class ELFT> bool ELFState<ELFT>::buildSectionIndex() {
>> - SN2I.addName(".symtab", getDotSymTabSecNo());
>> - SN2I.addName(".strtab", getDotStrTabSecNo());
>> - SN2I.addName(".shstrtab", getDotShStrTabSecNo());
>> -
>> for (unsigned i = 0, e = Doc.Sections.size(); i != e; ++i) {
>> StringRef Name = Doc.Sections[i]->Name;
>> + DotShStrtab.add(Name);
>> if (Name.empty())
>> continue;
>> // "+ 1" to take into account the SHT_NULL entry.
>> @@ -562,6 +565,17 @@ template <class ELFT> bool ELFState<ELFT
>> return false;
>> }
>> }
>> +
>> + auto SecNo = 1 + Doc.Sections.size();
>> + // Add special sections after input sections, if necessary.
>> + for (const auto &Name : ImplicitSecNames)
>> + if (!SN2I.addName(Name, SecNo)) {
>> + // Account for this section, since it wasn't in the Doc
>> + ++SecNo;
>> + DotShStrtab.add(Name);
>> + }
>> +
>> + DotShStrtab.finalize();
>> return true;
>> }
>>
>> @@ -608,32 +622,23 @@ int ELFState<ELFT>::writeELF(raw_ostream
>> Header.e_shentsize * Header.e_shnum;
>> ContiguousBlobAccumulator CBA(SectionContentBeginOffset);
>>
>> - // Doc might not contain .symtab, .strtab and .shstrtab sections,
>> - // but we will emit them, so make sure to add them to ShStrTabSHeader.
>> - State.DotShStrtab.add(".symtab");
>> - State.DotShStrtab.add(".strtab");
>> - State.DotShStrtab.add(".shstrtab");
>> -
>> std::vector<Elf_Shdr> SHeaders;
>> + SHeaders.reserve(State.SN2I.size());
>> if(!State.initSectionHeaders(SHeaders, CBA))
>> return 1;
>>
>> - // .symtab section.
>> - Elf_Shdr SymtabSHeader;
>> - State.initSymtabSectionHeader(SymtabSHeader, CBA);
>> - SHeaders.push_back(SymtabSHeader);
>> -
>> - // .strtab string table header.
>> - Elf_Shdr DotStrTabSHeader;
>> - State.initStrtabSectionHeader(DotStrTabSHeader, ".strtab", State.DotStrtab,
>> - CBA);
>> - SHeaders.push_back(DotStrTabSHeader);
>> -
>> - // .shstrtab string table header.
>> - Elf_Shdr ShStrTabSHeader;
>> - State.initStrtabSectionHeader(ShStrTabSHeader, ".shstrtab", State.DotShStrtab,
>> - CBA);
>> - SHeaders.push_back(ShStrTabSHeader);
>> + // Populate SHeaders with implicit sections not present in the Doc
>> + for (const auto &Name : ImplicitSecNames)
>> + if (State.SN2I.get(Name) >= SHeaders.size())
>> + SHeaders.push_back({});
>> +
>> + // Initialize the implicit sections
>> + auto Index = State.SN2I.get(".symtab");
>> + State.initSymtabSectionHeader(SHeaders[Index], CBA);
>> + Index = State.SN2I.get(".strtab");
>> + State.initStrtabSectionHeader(SHeaders[Index], ".strtab", State.DotStrtab, CBA);
>> + Index = State.SN2I.get(".shstrtab");
>> + State.initStrtabSectionHeader(SHeaders[Index], ".shstrtab", State.DotShStrtab, CBA);
>>
>> // Now we can decide segment offsets
>> State.setProgramHeaderLayout(PHeaders, SHeaders);
>>
>>
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