Constify a few functions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185520 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index b5f6686..de51a43 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -114,9 +114,9 @@
   bool isInt() const         { return EntryKind == E_Integer; }
   bool isConstantFP() const  { return EntryKind == E_ConstantFP; }
   bool isConstantInt() const { return EntryKind == E_ConstantInt; }
-  int64_t getInt()                    { return Constants.Int; }
-  const ConstantFP *getConstantFP()   { return Constants.CFP; }
-  const ConstantInt *getConstantInt() { return Constants.CIP; }
+  int64_t getInt() const                    { return Constants.Int; }
+  const ConstantFP *getConstantFP() const   { return Constants.CFP; }
+  const ConstantInt *getConstantInt() const { return Constants.CIP; }
 } DotDebugLocEntry;
 
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