[PECOFF] Support yet another new type of weak symbol.

COMDAT_SELECT_LARGEST is a COMDAT type that make linker to choose the largest
definition from among all of the definition of a symbol. If the size is the
same, the choice is arbitrary.

Differential Revision: http://llvm-reviews.chandlerc.com/D3011

llvm-svn: 204172

2 files changed, 4 insertions, 1 deletions

diff --git a/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp b/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
index b5f0de049d5..c32ca9762d9 100644
--- a/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
+++ b/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
@@ -250,11 +250,13 @@ DefinedAtom::Merge getMerge(const coff_aux_section_definition *auxsym) {
   case llvm::COFF::IMAGE_COMDAT_SELECT_ANY:
     return DefinedAtom::mergeAsWeakAndAddressUsed;
   case llvm::COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
+    // TODO: This mapping is wrong. Fix it.
     return DefinedAtom::mergeByContent;
   case llvm::COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
     return DefinedAtom::mergeSameNameAndSize;
-  case llvm::COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
   case llvm::COFF::IMAGE_COMDAT_SELECT_LARGEST:
+    return DefinedAtom::mergeByLargestSection;
+  case llvm::COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
   case llvm::COFF::IMAGE_COMDAT_SELECT_NEWEST:
     // FIXME: These attributes has more complicated semantics than the regular
     // weak symbol. These are mapped to mergeAsWeakAndAddressUsed for now
diff --git a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
index fe3cffdafe4..e4c809f11d2 100644
--- a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
+++ b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
@@ -340,6 +340,7 @@ template <> struct ScalarEnumerationTraits<lld::DefinedAtom::Merge> {
     io.enumCase(value, "by-content",   lld::DefinedAtom::mergeByContent);
     io.enumCase(value, "same-name-and-size",
                 lld::DefinedAtom::mergeSameNameAndSize);
+    io.enumCase(value, "largest", lld::DefinedAtom::mergeByLargestSection);
   }
 };