[yaml2obj/obj2yaml] - Add support for SHT_HASH sections.

SHT_HASH specification is:
http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash

In short the format is the following: it has 2 uint32 fields
in its header: nbucket and nchain followed by (nbucket + nchain)
uint32 values.

This patch allows dumping and parsing such sections.

Differential revision: https://reviews.llvm.org/D68085

llvm-svn: 373315

2 files changed, 64 insertions, 1 deletions

diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
index 6edc3c8e763..5acb02a5a57 100644
--- a/llvm/lib/ObjectYAML/ELFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -171,6 +171,9 @@ template <class ELFT> class ELFState {
   void writeSectionContent(Elf_Shdr &SHeader,
                            const ELFYAML::StackSizesSection &Section,
                            ContiguousBlobAccumulator &CBA);
+  void writeSectionContent(Elf_Shdr &SHeader,
+                           const ELFYAML::HashSection &Section,
+                           ContiguousBlobAccumulator &CBA);
   ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH);
 
 public:
@@ -417,7 +420,9 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
     } else if (auto S = dyn_cast<ELFYAML::VerdefSection>(Sec)) {
       writeSectionContent(SHeader, *S, CBA);
     } else if (auto S = dyn_cast<ELFYAML::StackSizesSection>(Sec)) {
-      writeSectionContent(SHeader, *S, CBA);  
+      writeSectionContent(SHeader, *S, CBA);
+    } else if (auto S = dyn_cast<ELFYAML::HashSection>(Sec)) {
+      writeSectionContent(SHeader, *S, CBA);
     } else {
       llvm_unreachable("Unknown section type");
     }
@@ -810,6 +815,34 @@ void ELFState<ELFT>::writeSectionContent(
 
 template <class ELFT>
 void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+                                         const ELFYAML::HashSection &Section,
+                                         ContiguousBlobAccumulator &CBA) {
+  raw_ostream &OS =
+      CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+
+  unsigned Link = 0;
+  if (SN2I.lookup(".dynsym", Link))
+    SHeader.sh_link = Link;
+
+  if (Section.Content) {
+    SHeader.sh_size = writeContent(OS, Section.Content, None);
+    return;
+  }
+
+  support::endian::write<uint32_t>(OS, Section.Bucket->size(),
+                                   ELFT::TargetEndianness);
+  support::endian::write<uint32_t>(OS, Section.Chain->size(),
+                                   ELFT::TargetEndianness);
+  for (uint32_t Val : *Section.Bucket)
+    support::endian::write<uint32_t>(OS, Val, ELFT::TargetEndianness);
+  for (uint32_t Val : *Section.Chain)
+    support::endian::write<uint32_t>(OS, Val, ELFT::TargetEndianness);
+
+  SHeader.sh_size = (2 + Section.Bucket->size() + Section.Chain->size()) * 4;
+}
+
+template <class ELFT>
+void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
                                          const ELFYAML::VerdefSection &Section,
                                          ContiguousBlobAccumulator &CBA) {
   typedef typename ELFT::Verdef Elf_Verdef;
diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index 94b1df10439..3a09a11ad83 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -1024,6 +1024,13 @@ static void sectionMapping(IO &IO, ELFYAML::StackSizesSection &Section) {
   IO.mapOptional("Entries", Section.Entries);
 }
 
+static void sectionMapping(IO &IO, ELFYAML::HashSection &Section) {
+  commonSectionMapping(IO, Section);
+  IO.mapOptional("Content", Section.Content);
+  IO.mapOptional("Bucket", Section.Bucket);
+  IO.mapOptional("Chain", Section.Chain);
+}
+
 static void sectionMapping(IO &IO, ELFYAML::NoBitsSection &Section) {
   commonSectionMapping(IO, Section);
   IO.mapOptional("Size", Section.Size, Hex64(0));
@@ -1123,6 +1130,11 @@ void MappingTraits<std::unique_ptr<ELFYAML::Section>>::mapping(
       Section.reset(new ELFYAML::NoBitsSection());
     sectionMapping(IO, *cast<ELFYAML::NoBitsSection>(Section.get()));
     break;
+  case ELF::SHT_HASH:
+    if (!IO.outputting())
+      Section.reset(new ELFYAML::HashSection());
+    sectionMapping(IO, *cast<ELFYAML::HashSection>(Section.get()));
+    break;
   case ELF::SHT_MIPS_ABIFLAGS:
     if (!IO.outputting())
       Section.reset(new ELFYAML::MipsABIFlags());
@@ -1196,6 +1208,24 @@ StringRef MappingTraits<std::unique_ptr<ELFYAML::Section>>::validate(
       return ".stack_sizes: Content and Entries cannot be used together";
     return {};
   }
+
+  if (const auto *HS = dyn_cast<ELFYAML::HashSection>(Section.get())) {
+    if (!HS->Content && !HS->Bucket && !HS->Chain)
+      return "one of \"Content\", \"Bucket\" or \"Chain\" must be specified";
+
+    if (HS->Content) {
+      if (HS->Bucket)
+        return "\"Content\" and \"Bucket\" cannot be used together";
+      if (HS->Chain)
+        return "\"Content\" and \"Chain\" cannot be used together";
+      return {};
+    }
+
+    if ((HS->Bucket && !HS->Chain) || (!HS->Bucket && HS->Chain))
+      return "\"Bucket\" and \"Chain\" must be used together";
+    return {};
+  }
+
   return {};
 }