Avoid decode_objc clobbering current language

Avoid decode_objc clobbering current language

[Andreas Schwab]

This fixes the failure in gdb.ada/frame_args.exp:

(gdb) break break_me
Breakpoint 1 at 0x10001170: file /cvs/gdb/gdb/testsuite/gdb.ada/frame_args/pck.adb, line 21.
(gdb) run 
Starting program: /sykes/cvs/test/ppc/gdb/gdb/testsuite/gdb.ada/frame_args/foo 
Error in re-setting breakpoint 1: Function "break_me" not defined.

Program exited normally.
(gdb) FAIL: gdb.ada/frame_args.exp: running to break_me in runto

The problem is that sal_decode_line_1 (here called from
breakpoint_re_set_one) calls decode_objc, which indirectly calls
get_selected_frame.  Since the program is just being started there is no
selected frame yet, thus get_selected_frame called select_frame, which
re-sets current_language (typically to language_c).  Thus the
set_language call in breakpoint_re_set_one is useless.

Andreas.

2008-05-21  Andreas Schwab  <schwab@suse.de>

	* linespec.c (decode_objc): Save current language around call to
	get_selected_block.

--- gdb/linespec.c.~1.79.~	2008-05-20 10:58:04.000000000 +0200
+++ gdb/linespec.c	2008-05-21 18:17:04.000000000 +0200
@@ -1116,8 +1116,16 @@ decode_objc (char **argptr, int funfirst
   if (file_symtab != NULL)
     block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (file_symtab), STATIC_BLOCK);
   else
-    block = get_selected_block (0);
-    
+    {
+      enum language save_language;
+
+      /* get_selected_block can change the current language when there is
+	 no selected frame yet.  */
+      save_language = current_language->la_language;
+      block = get_selected_block (0);
+      set_language (save_language);
+    }
+
   copy = find_imps (file_symtab, block, *argptr, NULL, &i1, &i2); 
     
   if (i1 > 0)

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: Avoid decode_objc clobbering current language

[Joel Brobecker]

Hi Andreas,

> The problem is that sal_decode_line_1 (here called from
> breakpoint_re_set_one) calls decode_objc, which indirectly calls
> get_selected_frame.  Since the program is just being started there is no
> selected frame yet, thus get_selected_frame called select_frame, which
> re-sets current_language (typically to language_c).  Thus the
> set_language call in breakpoint_re_set_one is useless.

This is an issue that I'm planning to address properly. I had some plans
earlier this year to do it, but then decided to think about it some more.
Basically, the idea is to reduce the use of the current_language to
the minimum, which is use it as the context when the user enters a
command.

It's one of the things that I want to get done around July to September.

> 2008-05-21  Andreas Schwab  <schwab@suse.de>
> 
> 	* linespec.c (decode_objc): Save current language around call to
> 	get_selected_block.

In the meantime, I think that this is reasonable. Eventually when
the change mentioned above gets under way, I will remove your change.
I feel confident that it will not be missed, because I will have to
review all the uses of current_language anyway. I hope I'm not missing
something!

So, if you confirm that this caused no regression, please go ahead and
commit.

-- 
Joel

Re: Avoid decode_objc clobbering current language

[Andreas Schwab]

Joel Brobecker <brobecker@adacore.com> writes:

> So, if you confirm that this caused no regression, please go ahead and
> commit.

I had tested it on powerpc-linux.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."