[yaml2obj/obj2yaml] - Move `Info` field out from `Section` class.

ELFYAML.h contains a `Section` class which is a base for a few other
sections classes that are used for mapping different section types.
`Section` has a `StringRef Info` field used for storing sh_info.

At the same time, sh_info has very different meanings for sections and
cannot be processed in a similar way generally,
for example ELFDumper does not handle it in `dumpCommonSection`
but do that in `dumpGroup` and `dumpCommonRelocationSection` respectively.

At this moment, we have and handle it as a string, because that was possible for
the current use case. But also it can simply be a number:
For SHT_GNU_verdef is "The number of version definitions within the section."

The patch moves `Info` field out to be able to have it as a number. 
With that change, each class will be able to decide what type and purpose
of the sh_info field it wants to use.

I also had to edit 2 test cases. This is because patch fixes a bug. Previously we 
accepted yaml files with Info fields for all sections (for example, for SHT_DYNSYM too).
But we do not handle it and the resulting objects had zero sh_info fields set for
such sections. Now it is accepted only for sections that supports it.

Differential revision: https://reviews.llvm.org/D58054

llvm-svn: 353810

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index 339f080337a..cec56771e1d 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -854,7 +854,6 @@ static void commonSectionMapping(IO &IO, ELFYAML::Section &Section) {
   IO.mapOptional("Link", Section.Link, StringRef());
   IO.mapOptional("AddressAlign", Section.AddressAlign, Hex64(0));
   IO.mapOptional("EntSize", Section.EntSize);
-  IO.mapOptional("Info", Section.Info, StringRef());
 }
 
 static void sectionMapping(IO &IO, ELFYAML::DynamicSection &Section) {
@@ -875,12 +874,14 @@ static void sectionMapping(IO &IO, ELFYAML::NoBitsSection &Section) {
 
 static void sectionMapping(IO &IO, ELFYAML::RelocationSection &Section) {
   commonSectionMapping(IO, Section);
+  IO.mapOptional("Info", Section.RelocatableSec, StringRef());
   IO.mapOptional("Relocations", Section.Relocations);
 }
 
-static void groupSectionMapping(IO &IO, ELFYAML::Group &group) {
-  commonSectionMapping(IO, group);
-  IO.mapRequired("Members", group.Members);
+static void groupSectionMapping(IO &IO, ELFYAML::Group &Group) {
+  commonSectionMapping(IO, Group);
+  IO.mapOptional("Info", Group.Signature, StringRef());
+  IO.mapRequired("Members", Group.Members);
 }
 
 void MappingTraits<ELFYAML::SectionOrType>::mapping(