If ELF subtargets don't want to support 4/8/16-byte mergable sections, allow 
them to null out the default section pointers.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79078 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp
index 4be0b9e..a695e24 100644
--- a/lib/Target/TargetLoweringObjectFile.cpp
+++ b/lib/Target/TargetLoweringObjectFile.cpp
@@ -578,11 +578,11 @@
   }
   
   if (Kind.isMergeableConst()) {
-    if (Kind.isMergeableConst4())
+    if (Kind.isMergeableConst4() && MergeableConst4Section)
       return MergeableConst4Section;
-    if (Kind.isMergeableConst8())
+    if (Kind.isMergeableConst8() && MergeableConst8Section)
       return MergeableConst8Section;
-    if (Kind.isMergeableConst16())
+    if (Kind.isMergeableConst16() && MergeableConst16Section)
       return MergeableConst16Section;
     return ReadOnlySection;  // .const
   }