commit 5b118a0471435751f39eeb92d56ecc3956053304
author Georgii Rymar <grimar@accesssoftek.com> Mon Oct 28 13:30:05 2019 +0300
committer Georgii Rymar <grimar@accesssoftek.com> Tue Oct 29 11:09:12 2019 +0300
tree bf63bbed8c429a3bb4a095a6df6b6196bde0e0e5
parent 5a955cc8b95a88fd0489d9b0a36ec86941ba6337

[yaml2obj] - Improve handling of the SHT_GROUP section.

Currently, when we do not specify "Info" field in a YAML description
for SHT_GROUP section, yaml2obj reports an error:
"error: unknown symbol referenced: '' by YAML section '.group1'"

Also, we do not link it with a symbol table by default,
though it is what we do for AddrsigSection, HashSection, RelocationSection.
(http://www.sco.com/developers/gabi/latest/ch4.sheader.html#sh_link)

The patch fixes missings mentioned.

Differential revision: https://reviews.llvm.org/D69299

llvm/lib/ObjectYAML/ELFEmitter.cpp

diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
index d5cdb85..6a4e00c 100644
--- a/llvm/lib/ObjectYAML/ELFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -791,10 +791,16 @@
   assert(Section.Type == llvm::ELF::SHT_GROUP &&
          "Section type is not SHT_GROUP");
 
+  unsigned Link = 0;
+  if (Section.Link.empty() && SN2I.lookup(".symtab", Link))
+    SHeader.sh_link = Link;
+
   SHeader.sh_entsize = 4;
   SHeader.sh_size = SHeader.sh_entsize * Section.Members.size();
-  SHeader.sh_info =
-      toSymbolIndex(Section.Signature, Section.Name, /*IsDynamic=*/false);
+
+  if (Section.Signature)
+    SHeader.sh_info =
+        toSymbolIndex(*Section.Signature, Section.Name, /*IsDynamic=*/false);
 
   raw_ostream &OS =
       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);