[patch] Code cleanup: New SYMBOL_HASH_NEXT

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

changing the internal hashing expression was tricky, make it easier.

This is a pre-requisite for a case-insensitivity patch repost to be (re)posted
later.

I will check it in, this patch has no functionality change.


Thanks,
Jan


gdb/
2011-04-02  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Code cleanup.
	* dictionary.c (dict_hash): Use SYMBOL_HASH_NEXT.
	* dwarf2read.c (mapped_index_string_hash): Refer to SYMBOL_HASH_NEXT
	in the function comment, a new note on values compatibility.
	* minsyms.c (msymbol_hash_iw, msymbol_hash): Use SYMBOL_HASH_NEXT.
	* symtab.h (SYMBOL_HASH_NEXT): New.

--- a/gdb/dictionary.c
+++ b/gdb/dictionary.c
@@ -826,7 +826,7 @@ dict_hash (const char *string0)
 	    }
 	  /* FALL THROUGH */
 	default:
-	  hash = hash * 67 + *string - 113;
+	  hash = SYMBOL_HASH_NEXT (hash, *string);
 	  string += 1;
 	  break;
 	}
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -1962,11 +1962,11 @@ create_addrmap_from_index (struct objfile *objfile, struct mapped_index *index)
   do_cleanups (cleanup);
 }
 
-/* The hash function for strings in the mapped index.  This is the
-   same as the hashtab.c hash function, but we keep a separate copy to
-   maintain control over the implementation.  This is necessary
-   because the hash function is tied to the format of the mapped index
-   file.  */
+/* The hash function for strings in the mapped index.  This is the same as
+   SYMBOL_HASH_NEXT, but we keep a separate copy to maintain control over the
+   implementation.  This is necessary because the hash function is tied to the
+   format of the mapped index file.  The hash values do not have to match with
+   SYMBOL_HASH_NEXT.  */
 
 static hashval_t
 mapped_index_string_hash (const void *p)
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -91,7 +91,7 @@ msymbol_hash_iw (const char *string)
 	++string;
       if (*string && *string != '(')
 	{
-	  hash = hash * 67 + *string - 113;
+	  hash = SYMBOL_HASH_NEXT (hash, *string);
 	  ++string;
 	}
     }
@@ -106,7 +106,7 @@ msymbol_hash (const char *string)
   unsigned int hash = 0;
 
   for (; *string; ++string)
-    hash = hash * 67 + *string - 113;
+    hash = SYMBOL_HASH_NEXT (hash, *string);
   return hash;
 }
 
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -1020,6 +1020,12 @@ extern unsigned int msymbol_hash_iw (const char *);
 
 extern unsigned int msymbol_hash (const char *);
 
+/* Compute the next hash value from previous HASH and the character C.  This
+   is only a GDB in-memory computed value with no external files compatibility
+   requirements.  */
+
+#define SYMBOL_HASH_NEXT(hash, c) ((hash) * 67 + (c) - 113)
+
 extern struct objfile * msymbol_objfile (struct minimal_symbol *sym);
 
 extern void