[ELFYAML] Fix handling SHT_NOBITS sections by obj2yaml/yaml2obj tools

SHT_NOBITS sections do not have content in an object file. Now the yaml2obj
tool does not accept `Content` field for such sections, and the obj2yaml
tool does not attempt to read the section content from a file.

Restore r241350 and r241352.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241377 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Object/ELFYAML.h b/include/llvm/Object/ELFYAML.h
index b45507920a9c61af52fd32f2bbb8c923f5f679f7..df0aa500c8a29d6b552a3432a02ad2a9335a0722 100644 (file)
--- a/include/llvm/Object/ELFYAML.h
+++ b/include/llvm/Object/ELFYAML.h
@@ -85,7 +85,13 @@ struct SectionOrType {
 };
 
 struct Section {
-  enum class SectionKind { Group, RawContent, Relocation, MipsABIFlags };
+  enum class SectionKind {
+    Group,
+    RawContent,
+    Relocation,
+    NoBits,
+    MipsABIFlags
+  };
   SectionKind Kind;
   StringRef Name;
   ELF_SHT Type;
@@ -106,6 +112,14 @@ struct RawContentSection : Section {
   }
 };
 
+struct NoBitsSection : Section {
+  llvm::yaml::Hex64 Size;
+  NoBitsSection() : Section(SectionKind::NoBits) {}
+  static bool classof(const Section *S) {
+    return S->Kind == SectionKind::NoBits;
+  }
+};
+
 struct Group : Section {
   // Members of a group contain a flag and a list of section indices
   // that are part of the group.

diff --git a/lib/Object/ELFYAML.cpp b/lib/Object/ELFYAML.cpp
index ecdd468305bebf9f4772f92fde6ae39959f980e4..72c232c3287065c83c77e913eddbf2564c665a95 100644 (file)
--- a/lib/Object/ELFYAML.cpp
+++ b/lib/Object/ELFYAML.cpp
@@ -627,6 +627,11 @@ static void sectionMapping(IO &IO, ELFYAML::RawContentSection &Section) {
   IO.mapOptional("Size", Section.Size, Hex64(Section.Content.binary_size()));
 }
 
+static void sectionMapping(IO &IO, ELFYAML::NoBitsSection &Section) {
+  commonSectionMapping(IO, Section);
+  IO.mapOptional("Size", Section.Size, Hex64(0));
+}
+
 static void sectionMapping(IO &IO, ELFYAML::RelocationSection &Section) {
   commonSectionMapping(IO, Section);
   IO.mapOptional("Relocations", Section.Relocations);
@@ -682,6 +687,11 @@ void MappingTraits<std::unique_ptr<ELFYAML::Section>>::mapping(
       Section.reset(new ELFYAML::Group());
     groupSectionMapping(IO, *cast<ELFYAML::Group>(Section.get()));
     break;
+  case ELF::SHT_NOBITS:
+    if (!IO.outputting())
+      Section.reset(new ELFYAML::NoBitsSection());
+    sectionMapping(IO, *cast<ELFYAML::NoBitsSection>(Section.get()));
+    break;
   case ELF::SHT_MIPS_ABIFLAGS:
     if (!IO.outputting())
       Section.reset(new ELFYAML::MipsABIFlags());

diff --git a/test/Object/obj2yaml.test b/test/Object/obj2yaml.test
index 08000f66581bd3c5278b6c9cc70ca9b77159c3ae..8054b23eb560bee2c5917370d36c899bc99f6fe2 100644 (file)
--- a/test/Object/obj2yaml.test
+++ b/test/Object/obj2yaml.test
@@ -234,7 +234,7 @@ ELF-MIPSEL-NEXT:   - Name:            .bss
 ELF-MIPSEL-NEXT:     Type:            SHT_NOBITS
 ELF-MIPSEL-NEXT:     Flags:           [ SHF_WRITE, SHF_ALLOC ]
 ELF-MIPSEL-NEXT:     AddressAlign:    0x0000000000000004
-ELF-MIPSEL-NEXT:     Content:         48656C6C
+ELF-MIPSEL-NEXT:     Size:            0x0000000000000004
 ELF-MIPSEL-NEXT:   - Name:            .mdebug.abi32
 ELF-MIPSEL-NEXT:     Type:            SHT_PROGBITS
 ELF-MIPSEL-NEXT:     AddressAlign:    0x0000000000000001
@@ -324,7 +324,6 @@ ELF-MIPS64EL-NEXT:   - Name:            .bss
 ELF-MIPS64EL-NEXT:     Type:            SHT_NOBITS
 ELF-MIPS64EL-NEXT:     Flags:           [ SHF_WRITE, SHF_ALLOC ]
 ELF-MIPS64EL-NEXT:     AddressAlign:    0x0000000000000010
-ELF-MIPS64EL-NEXT:     Content:         ''
 ELF-MIPS64EL-NEXT:   - Name:            .MIPS.options
 ELF-MIPS64EL-NEXT:     Type:            SHT_MIPS_OPTIONS
 ELF-MIPS64EL-NEXT:     Flags:           [ SHF_ALLOC ]

diff --git a/test/Object/yaml2obj-elf-rel-noref.yaml b/test/Object/yaml2obj-elf-rel-noref.yaml
index 69fcf08544343728aa74dc31afd3ca510f057332..4a13acd1fd382638c48127dcbe34f9ad91f89aec 100644 (file)
--- a/test/Object/yaml2obj-elf-rel-noref.yaml
+++ b/test/Object/yaml2obj-elf-rel-noref.yaml
@@ -32,7 +32,7 @@ Sections:
     Type:            SHT_NOBITS
     Flags:           [ SHF_WRITE, SHF_ALLOC ]
     AddressAlign:    0x0000000000000001
-    Content:         ''
+    Size:            0
   - Name:            .ARM.attributes
     Type:            SHT_ARM_ATTRIBUTES
     AddressAlign:    0x0000000000000001

diff --git a/tools/obj2yaml/elf2yaml.cpp b/tools/obj2yaml/elf2yaml.cpp
index 9afcedef63982e8fce6eeb366b0f8b27b497033c..f117a10d382227a4ad09fe4aac1a1547efac2b69 100644 (file)
--- a/tools/obj2yaml/elf2yaml.cpp
+++ b/tools/obj2yaml/elf2yaml.cpp
@@ -40,6 +40,7 @@ class ELFDumper {
   ErrorOr<ELFYAML::RelocationSection *> dumpRelaSection(const Elf_Shdr *Shdr);
   ErrorOr<ELFYAML::RawContentSection *>
   dumpContentSection(const Elf_Shdr *Shdr);
+  ErrorOr<ELFYAML::NoBitsSection *> dumpNoBitsSection(const Elf_Shdr *Shdr);
   ErrorOr<ELFYAML::Group *> dumpGroup(const Elf_Shdr *Shdr);
   ErrorOr<ELFYAML::MipsABIFlags *> dumpMipsABIFlags(const Elf_Shdr *Shdr);
 
@@ -104,6 +105,13 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(G.get()));
       break;
     }
+    case ELF::SHT_NOBITS: {
+      ErrorOr<ELFYAML::NoBitsSection *> S = dumpNoBitsSection(&Sec);
+      if (std::error_code EC = S.getError())
+        return EC;
+      Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
+      break;
+    }
     default: {
       ErrorOr<ELFYAML::RawContentSection *> S = dumpContentSection(&Sec);
       if (std::error_code EC = S.getError())
@@ -304,6 +312,18 @@ ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
   return S.release();
 }
 
+template <class ELFT>
+ErrorOr<ELFYAML::NoBitsSection *>
+ELFDumper<ELFT>::dumpNoBitsSection(const Elf_Shdr *Shdr) {
+  auto S = make_unique<ELFYAML::NoBitsSection>();
+
+  if (std::error_code EC = dumpCommonSection(Shdr, *S))
+    return EC;
+  S->Size = Shdr->sh_size;
+
+  return S.release();
+}
+
 template <class ELFT>
 ErrorOr<ELFYAML::Group *> ELFDumper<ELFT>::dumpGroup(const Elf_Shdr *Shdr) {
   auto S = make_unique<ELFYAML::Group>();

diff --git a/tools/yaml2obj/yaml2elf.cpp b/tools/yaml2obj/yaml2elf.cpp
index 772b5b918ecab9cbe4989e59fb60ee7a77417555..2cbc338035823889506bac88148a9227afcff289 100644 (file)
--- a/tools/yaml2obj/yaml2elf.cpp
+++ b/tools/yaml2obj/yaml2elf.cpp
@@ -241,6 +241,12 @@ bool ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
     } else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec.get())) {
       if (!writeSectionContent(SHeader, *S, CBA))
         return false;
+    } else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec.get())) {
+      SHeader.sh_entsize = 0;
+      SHeader.sh_size = S->Size;
+      // SHT_NOBITS section does not have content
+      // so just to setup the section offset.
+      CBA.getOSAndAlignedOffset(SHeader.sh_offset);
     } else
       llvm_unreachable("Unknown section type");