Allow L symbols in no_dead_strip sections.

If a section cannot be dead stripped, it is safe to use L symbols, since
the linker will keep all of it in the end.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221431 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/TargetLoweringObjectFileImpl.cpp

@@ -588,6 +588,10 @@ bool TargetLoweringObjectFileMachO::isSectionAtomizableBySymbols(
         SMO.getSectionName() == "__cfstring")
       return false;
 
+    // no_dead_strip sections are not atomized in practice.
+    if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
+      return false;
+
     switch (SMO.getType()) {
     default:
       return true;