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

Note: this is a reland with a trivial 2 lines fix in ELFState<ELFT>::writeSectionContent.
      It adds a check similar to ones we already have for other sections to fix the case revealed
      by bots, like http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/60744.

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, 12 insertions, 0 deletions

diff --git a/llvm/include/llvm/ObjectYAML/ELFYAML.h b/llvm/include/llvm/ObjectYAML/ELFYAML.h
index c9f14589906..f87135e6a1b 100644
--- a/llvm/include/llvm/ObjectYAML/ELFYAML.h
+++ b/llvm/include/llvm/ObjectYAML/ELFYAML.h
@@ -138,6 +138,7 @@ struct Chunk {
     Group,
     RawContent,
     Relocation,
+    Relr,
     NoBits,
     Note,
     Hash,
@@ -440,6 +441,17 @@ struct RelocationSection : Section {
   }
 };
 
+struct RelrSection : Section {
+  Optional<std::vector<llvm::yaml::Hex64>> Entries;
+  Optional<yaml::BinaryRef> Content;
+
+  RelrSection() : Section(ChunkKind::Relr) {}
+
+  static bool classof(const Chunk *S) {
+    return S->Kind == ChunkKind::Relr;
+  }
+};
+
 struct SymtabShndxSection : Section {
   std::vector<uint32_t> Entries;