[yaml2obj][ELF] Don't explicitly set `Binding` with STB_*

Instead, just have 3 sub-lists, one for each of
{STB_LOCAL,STB_GLOBAL,STB_WEAK}.

This allows us to be a lot more explicit w.r.t. the symbol ordering in
the object file, because if we allowed explicitly setting the STB_*
`Binding` key for the symbol, then we might have ended up having to
shuffle STB_LOCAL symbols to the front of the list, which is likely to
cause confusion and potential for error.

Also, this new approach is simpler ;)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184506 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Object/ELFYAML.cpp b/lib/Object/ELFYAML.cpp
index 7fa7756..107333c 100644
--- a/lib/Object/ELFYAML.cpp
+++ b/lib/Object/ELFYAML.cpp
@@ -278,15 +278,6 @@
 #undef BCase
 }
 
-void ScalarEnumerationTraits<ELFYAML::ELF_STB>::enumeration(
-    IO &IO, ELFYAML::ELF_STB &Value) {
-#define ECase(X) IO.enumCase(Value, #X, ELF::X);
-  ECase(STB_LOCAL)
-  ECase(STB_GLOBAL)
-  ECase(STB_WEAK)
-#undef ECase
-}
-
 void ScalarEnumerationTraits<ELFYAML::ELF_STT>::enumeration(
     IO &IO, ELFYAML::ELF_STT &Value) {
 #define ECase(X) IO.enumCase(Value, #X, ELF::X);
@@ -313,13 +304,19 @@
 
 void MappingTraits<ELFYAML::Symbol>::mapping(IO &IO, ELFYAML::Symbol &Symbol) {
   IO.mapOptional("Name", Symbol.Name, StringRef());
-  IO.mapOptional("Binding", Symbol.Binding, ELFYAML::ELF_STB(0));
   IO.mapOptional("Type", Symbol.Type, ELFYAML::ELF_STT(0));
   IO.mapOptional("Section", Symbol.Section, StringRef());
   IO.mapOptional("Value", Symbol.Value, Hex64(0));
   IO.mapOptional("Size", Symbol.Size, Hex64(0));
 }
 
+void MappingTraits<ELFYAML::LocalGlobalWeakSymbols>::mapping(
+    IO &IO, ELFYAML::LocalGlobalWeakSymbols &Symbols) {
+  IO.mapOptional("Local", Symbols.Local);
+  IO.mapOptional("Global", Symbols.Global);
+  IO.mapOptional("Weak", Symbols.Weak);
+}
+
 void MappingTraits<ELFYAML::Section>::mapping(IO &IO,
                                               ELFYAML::Section &Section) {
   IO.mapOptional("Name", Section.Name, StringRef());