[core] support .gnu.linkonce sections

.gnu.linkonce sections are similar to section groups. They were supported before
section groups existed and provided a way to resolve COMDAT sections using a
different design. There are few implementations that use .gnu.linkonce sections
to store simple floating point constants which doesnot require complex section
group support but need a way to store only one copy of the floating point
constant. .gnu.linkonce based symbol resolution achieves that.

llvm-svn: 205163

1 files changed, 7 insertions, 3 deletions

diff --git a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
index 49de7f551cf..b2295f87d66 100644
--- a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
+++ b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
@@ -71,7 +71,9 @@ public:
       if (!atom->name().empty())
         buildDuplicateNameMap(*atom);
 
-      if (atom->contentType() == DefinedAtom::typeGroupComdat) {
+      if (atom->contentType() == DefinedAtom::typeGroupComdat ||
+          atom->contentType() == DefinedAtom::typeGnuLinkOnce) {
+
         for (const lld::Reference *ref : *atom) {
           if (ref->kindNamespace() != lld::Reference::KindNamespace::all)
             continue;
@@ -229,7 +231,8 @@ private:
     }
 
     if (const lld::DefinedAtom *da = dyn_cast<DefinedAtom>(atom)) {
-      if (da->contentType() == DefinedAtom::typeGroupComdat) {
+      if (da->contentType() == DefinedAtom::typeGroupComdat ||
+          da->contentType() == DefinedAtom::typeGnuLinkOnce) {
         if (_groupMap.count(name)) {
           _io.setError(Twine("duplicate group name: ") + name);
         } else {
@@ -476,7 +479,8 @@ template <> struct ScalarEnumerationTraits<lld::DefinedAtom::ContentType> {
     io.enumCase(value, "ro-note",         DefinedAtom::typeRONote);
     io.enumCase(value, "rw-note",         DefinedAtom::typeRWNote);
     io.enumCase(value, "no-alloc",        DefinedAtom::typeNoAlloc);
-    io.enumCase(value, "group-comdat", DefinedAtom::typeGroupComdat);
+    io.enumCase(value, "group-comdat",    DefinedAtom::typeGroupComdat);
+    io.enumCase(value, "gnu-linkonce",    DefinedAtom::typeGnuLinkOnce);
   }
 };