[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

6 files changed, 13 insertions, 12 deletions

diff --git a/llvm/include/llvm/ObjectYAML/ELFYAML.h b/llvm/include/llvm/ObjectYAML/ELFYAML.h
index 5eff7fc651e..e194e59a485 100644
--- a/llvm/include/llvm/ObjectYAML/ELFYAML.h
+++ b/llvm/include/llvm/ObjectYAML/ELFYAML.h
@@ -129,7 +129,6 @@ struct Section {
   ELF_SHF Flags;
   llvm::yaml::Hex64 Address;
   StringRef Link;
-  StringRef Info;
   llvm::yaml::Hex64 AddressAlign;
   Optional<llvm::yaml::Hex64> EntSize;
 
@@ -172,6 +171,7 @@ struct Group : Section {
   // Members of a group contain a flag and a list of section indices
   // that are part of the group.
   std::vector<SectionOrType> Members;
+  StringRef Signature; /* Info */
 
   Group() : Section(SectionKind::Group) {}
 
@@ -189,6 +189,7 @@ struct Relocation {
 
 struct RelocationSection : Section {
   std::vector<Relocation> Relocations;
+  StringRef RelocatableSec; /* Info */
 
   RelocationSection() : Section(SectionKind::Relocation) {}
 
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(
diff --git a/llvm/test/tools/llvm-readobj/demangle.test b/llvm/test/tools/llvm-readobj/demangle.test
index edac38e18f2..809a7243edf 100644
--- a/llvm/test/tools/llvm-readobj/demangle.test
+++ b/llvm/test/tools/llvm-readobj/demangle.test
@@ -133,7 +133,6 @@ Sections:
     Type:         SHT_DYNSYM
     Flags:        [ SHF_ALLOC ]
     Link:         .dynstr
-    Info:         1
     Address:      0x100
     AddressAlign: 0x100
     EntSize:      0x18
diff --git a/llvm/test/tools/llvm-readobj/gnu-hash-symbols.test b/llvm/test/tools/llvm-readobj/gnu-hash-symbols.test
index 79e58a91619..8babac599c3 100644
--- a/llvm/test/tools/llvm-readobj/gnu-hash-symbols.test
+++ b/llvm/test/tools/llvm-readobj/gnu-hash-symbols.test
@@ -63,7 +63,6 @@ Sections:
     Type:         SHT_DYNSYM
     Flags:        [ SHF_ALLOC ]
     Link:         .dynstr
-    Info:         1
     Address:      0x100
     AddressAlign: 0x100
     EntSize:      0x18
diff --git a/llvm/tools/obj2yaml/elf2yaml.cpp b/llvm/tools/obj2yaml/elf2yaml.cpp
index a089890e9a3..a3fe811b9d5 100644
--- a/llvm/tools/obj2yaml/elf2yaml.cpp
+++ b/llvm/tools/obj2yaml/elf2yaml.cpp
@@ -354,7 +354,7 @@ ELFDumper<ELFT>::dumpCommonRelocationSection(const Elf_Shdr *Shdr,
   auto NameOrErr = getUniquedSectionName(*InfoSection);
   if (!NameOrErr)
     return errorToErrorCode(NameOrErr.takeError());
-  S.Info = NameOrErr.get();
+  S.RelocatableSec = NameOrErr.get();
 
   return obj2yaml_error::success;
 }
@@ -468,7 +468,7 @@ ErrorOr<ELFYAML::Group *> ELFDumper<ELFT>::dumpGroup(const Elf_Shdr *Shdr) {
   Expected<StringRef> symbolName = getSymbolName(symbol, StrTab, Symtab);
   if (!symbolName)
     return errorToErrorCode(symbolName.takeError());
-  S->Info = *symbolName;
+  S->Signature = *symbolName;
   const Elf_Word *groupMembers =
       reinterpret_cast<const Elf_Word *>(sectionContents->data());
   const long count = (Shdr->sh_size) / sizeof(Elf_Word);
diff --git a/llvm/tools/yaml2obj/yaml2elf.cpp b/llvm/tools/yaml2obj/yaml2elf.cpp
index c904523f4c9..5198a751cfb 100644
--- a/llvm/tools/yaml2obj/yaml2elf.cpp
+++ b/llvm/tools/yaml2obj/yaml2elf.cpp
@@ -270,15 +270,16 @@ bool ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
         SHeader.sh_link = getDotSymTabSecNo();
 
       unsigned Index;
-      if (!convertSectionIndex(SN2I, S->Name, S->Info, Index))
+      if (!convertSectionIndex(SN2I, S->Name, S->RelocatableSec, Index))
         return false;
       SHeader.sh_info = Index;
       if (!writeSectionContent(SHeader, *S, CBA))
         return false;
     } else if (auto S = dyn_cast<ELFYAML::Group>(Sec.get())) {
       unsigned SymIdx;
-      if (SymN2I.lookup(S->Info, SymIdx) && !to_integer(S->Info, SymIdx)) {
-        WithColor::error() << "Unknown symbol referenced: '" << S->Info
+      if (SymN2I.lookup(S->Signature, SymIdx) &&
+          !to_integer(S->Signature, SymIdx)) {
+        WithColor::error() << "Unknown symbol referenced: '" << S->Signature
                            << "' at YAML section '" << S->Name << "'.\n";
         return false;
       }