Re: [PATCH]

[Sergio Durigan Junior <sergiodj@redhat.com>]

Hi Joel,

Thank for the review.

On Wednesday, January 18 2012, Joel Brobecker wrote:

>> This patch is going to be important for the coming SystemTap patches
>> that I plan to submit this week, and I know GDB has a rule to avoid
>> premature modification of the code before a patch is posted, but I
>> believe this is a good cleanup to have in any case.
> [...]
>> 2012-01-18  Sergio Durigan Junior  <sergiodj@redhat.com>
>> 
>> 	* parse.c (initialize_expout): New function.
>> 	(reallocate_expout): Likewise.
>> 	(parse_exp_in_context): Use `initialize_expout' and
>> 	`reallocate_expout' when appropriate.
>
> FWIW, it seems OK to me on its own. I like the fact that you made
> the initial_size and gdbarch parameters.

Thanks.

> The description does seem to mention an argument that has not been
> added yet (parser_state PS). I haven't followed the discussion on
> the thread, but have we decided to keep "ps" as the name of the
> parser_state argument?

Sorry, this was actually another mistake.  I am getting crazy with so
many parser patches.  This argument is not present yet because the
parser cleanup is an ongoing work, so I will remove its mention on the
comment.  As for your question about the name: Tom asked me to change
the name to something else, so it's not going to be `ps' anymore.  But
that is probably a discussion for the other thread :-).

Anyway, here is the fixed version of the patch.

-- 
Sergio

2012-01-18  Sergio Durigan Junior  <sergiodj@redhat.com>

	* parse.c (initialize_expout): New function.
	(reallocate_expout): Likewise.
	(parse_exp_in_context): Use `initialize_expout' and
	`reallocate_expout' when appropriate.

diff --git a/gdb/parse.c b/gdb/parse.c
index f405dc5..1ce3b4b 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -182,6 +182,40 @@ free_funcalls (void *ignore)
 /* This page contains the functions for adding data to the struct expression
    being constructed.  */
 
+/* Helper function used to initialize an struct expression that is going
+   to be used to store expression elements.  The arguments are the
+   INITIAL_SIZE of the expression, the language LANG parsed to build this
+   expression, and the GDBARCH pointer.  */
+
+static void
+initialize_expout (int initial_size, const struct language_defn *lang,
+		   struct gdbarch *gdbarch)
+{
+  expout_size = initial_size;
+  expout_ptr = 0;
+  expout = xmalloc (sizeof (struct expression)
+		    + EXP_ELEM_TO_BYTES (expout_size));
+  expout->language_defn = lang;
+  expout->gdbarch = gdbarch;
+}
+
+/* Helper function that reallocates the EXPOUT in order to eliminate any
+   unused space.  It is generally used when the expression has just been
+   parsed and created.  */
+
+static void
+reallocate_expout (void)
+{
+  /* Record the actual number of expression elements, and then
+     reallocate the expression memory so that we free up any
+     excess elements.  */
+
+  expout->nelts = expout_ptr;
+  expout = xrealloc ((char *) expout,
+		     sizeof (struct expression)
+		     + EXP_ELEM_TO_BYTES (expout_ptr));
+}
+
 /* Add one element to the end of the expression.  */
 
 /* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
@@ -1156,12 +1190,7 @@ parse_exp_in_context (char **stringptr, struct block *block, int comma,
   else
     lang = current_language;
 
-  expout_size = 10;
-  expout_ptr = 0;
-  expout = (struct expression *)
-    xmalloc (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size));
-  expout->language_defn = lang;
-  expout->gdbarch = get_current_arch ();
+  initialize_expout (10, lang, get_current_arch ());
 
   TRY_CATCH (except, RETURN_MASK_ALL)
     {
@@ -1179,14 +1208,7 @@ parse_exp_in_context (char **stringptr, struct block *block, int comma,
 
   discard_cleanups (old_chain);
 
-  /* Record the actual number of expression elements, and then
-     reallocate the expression memory so that we free up any
-     excess elements.  */
-
-  expout->nelts = expout_ptr;
-  expout = (struct expression *)
-    xrealloc ((char *) expout,
-	      sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_ptr));
+  reallocate_expout ();
 
   /* Convert expression from postfix form as generated by yacc
      parser, to a prefix form.  */