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

The encoded sequence of Elf*_Relr entries in a SHT_RELR section looks
like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
i.e. start with an address, followed by any number of bitmaps. The address
entry encodes 1 relocation. The subsequent bitmap entries encode up to 63(31)
relocations each, at subsequent offsets following the last address entry.

More information is here:
https://github.com/llvm-mirror/llvm/blob/master/lib/Object/ELF.cpp#L272

This patch adds a support for these sections.

Differential revision: https://reviews.llvm.org/D71872

1 files changed, 17 insertions, 0 deletions

diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index 21ae85022c2..efa7ecb4728 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -1101,6 +1101,12 @@ static void sectionMapping(IO &IO, ELFYAML::RelocationSection &Section) {
   IO.mapOptional("Relocations", Section.Relocations);
 }
 
+static void sectionMapping(IO &IO, ELFYAML::RelrSection &Section) {
+  commonSectionMapping(IO, Section);
+  IO.mapOptional("Entries", Section.Entries);
+  IO.mapOptional("Content", Section.Content);
+}
+
 static void groupSectionMapping(IO &IO, ELFYAML::Group &Group) {
   commonSectionMapping(IO, Group);
   IO.mapOptional("Info", Group.Signature);
@@ -1200,6 +1206,11 @@ void MappingTraits<std::unique_ptr<ELFYAML::Chunk>>::mapping(
       Section.reset(new ELFYAML::RelocationSection());
     sectionMapping(IO, *cast<ELFYAML::RelocationSection>(Section.get()));
     break;
+  case ELF::SHT_RELR:
+    if (!IO.outputting())
+      Section.reset(new ELFYAML::RelrSection());
+    sectionMapping(IO, *cast<ELFYAML::RelrSection>(Section.get()));
+    break;
   case ELF::SHT_GROUP:
     if (!IO.outputting())
       Section.reset(new ELFYAML::Group());
@@ -1441,6 +1452,12 @@ StringRef MappingTraits<std::unique_ptr<ELFYAML::Chunk>>::validate(
     return {};
   }
 
+  if (const auto *RS = dyn_cast<ELFYAML::RelrSection>(C.get())) {
+    if (RS->Entries && RS->Content)
+      return "\"Entries\" and \"Content\" can't be used together";
+    return {};
+  }
+
   return {};
 }