DIEHash: Const correct and use references where non-null/non-rebound.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193363 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DIEHash.h b/lib/CodeGen/AsmPrinter/DIEHash.h
index 2869ce7..da373de 100644
--- a/lib/CodeGen/AsmPrinter/DIEHash.h
+++ b/lib/CodeGen/AsmPrinter/DIEHash.h
@@ -84,24 +84,24 @@
 
 public:
   /// \brief Computes the ODR signature.
-  uint64_t computeDIEODRSignature(DIE *Die);
+  uint64_t computeDIEODRSignature(const DIE &Die);
 
   /// \brief Computes the CU signature.
-  uint64_t computeCUSignature(DIE *Die);
+  uint64_t computeCUSignature(const DIE &Die);
 
   /// \brief Computes the type signature.
-  uint64_t computeTypeSignature(DIE *Die);
+  uint64_t computeTypeSignature(const DIE &Die);
 
   // Helper routines to process parts of a DIE.
 private:
   /// \brief Adds the parent context of \param Die to the hash.
-  void addParentContext(DIE *Die);
+  void addParentContext(const DIE &Die);
 
   /// \brief Adds the attributes of \param Die to the hash.
-  void addAttributes(DIE *Die);
+  void addAttributes(const DIE &Die);
 
   /// \brief Computes the full DWARF4 7.27 hash of the DIE.
-  void computeHash(DIE *Die);
+  void computeHash(const DIE &Die);
 
   // Routines that add DIEValues to the hash.
 private:
@@ -116,7 +116,7 @@
 
   /// \brief Collects the attributes of DIE \param Die into the \param Attrs
   /// structure.
-  void collectAttributes(DIE *Die, DIEAttrs &Attrs);
+  void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
 
   /// \brief Hashes the attributes in \param Attrs in order.
   void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
@@ -126,19 +126,19 @@
 
   /// \brief Hashes an attribute that refers to another DIE.
   void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
-                    DIE &Entry);
+                    const DIE &Entry);
 
   /// \brief Hashes a reference to a named type in such a way that is
   /// independent of whether that type is described by a declaration or a
   /// definition.
-  void hashShallowTypeReference(dwarf::Attribute Attribute,
-                                const DIE &Entry, StringRef Name);
+  void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
+                                StringRef Name);
 
   /// \brief Hashes a reference to a previously referenced type DIE.
   void hashRepeatedTypeReference(dwarf::Attribute Attribute, unsigned DieNumber);
 
 private:
   MD5 Hash;
-  DenseMap<DIE*, unsigned> Numbering;
+  DenseMap<const DIE *, unsigned> Numbering;
 };
 }