[Bug objc/11754] New: [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[Bug objc/11754] New: [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[alexander at malmberg dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754

           Summary: [objc-improvements-branch] receiver is evaluated twice
                    when passing messages with the gnu runtime
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: objc
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: alexander at malmberg dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu

When using the objc-improvements-branch (as of 2003-07-31) to compile for the
GNU runtime, the receiver in message calls is evaluated twice. The following
program:

<cut here>
#include <objc/Object.h>

@interface Foo : Object
+ foo;
+ bar;
@end

@implementation Foo
+ foo
{
    printf("foo\n");
    return self;
}
+ bar
{
    printf("bar\n");
    return self;
}
@end

int main(int argc,char **argv)
{
    [[Foo foo] bar];
    return 0;
}
</cut here>

prints:
""
foo
foo
bar
""
instead of the expected:
""
foo
bar
""

The following patch fixes it:

Index: gcc/objc/objc-act.c
===================================================================
RCS file: /cvsroot/gcc/gcc/gcc/objc/objc-act.c,v
retrieving revision 1.179.2.2
diff -u -r1.179.2.2 objc-act.c
--- gcc/objc/objc-act.c 29 Jul 2003 23:01:58 -0000      1.179.2.2
+++ gcc/objc/objc-act.c 31 Jul 2003 18:51:51 -0000
@@ -6017,8 +6017,11 @@
       tree method;
 
       /* Avoid trouble since we may evaluate each of these twice.  */
-      object = save_expr (object);
+      lookup_object = save_expr (lookup_object);
       selector = save_expr (selector);
+
+      if (!super_flag)
+       object = lookup_object;
 
       lookup_object = build_c_cast (rcv_p, lookup_object);

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[d dot ayers at inode dot at]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754


d dot ayers at inode dot at changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |d dot ayers at inode dot at

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754


pinskia at physics dot uc dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
   Target Milestone|3.4                         |---


------- Additional Comments From pinskia at physics dot uc dot edu  2003-07-31 20:26 -------
This also happens in "gcc version 3.3 20030304 (Apple Computer, Inc. build 1409)".

I have seen reports of this on one of the Darwin's mailing lists.

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[zlaski at apple dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754



------- Additional Comments From zlaski at apple dot com  2003-07-31 20:59 -------
Thanks for catching this.  Can you create a test case for this as well (and commit both it and the 
patch)?  Thanks.  Both the bug and the fix appear to be -fgnu-runtime specific.

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[geoffk at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754


geoffk at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |zlaski at apple dot com
                   |dot org                     |
             Status|UNCONFIRMED                 |ASSIGNED

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[cvs-commit at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754



------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-07-31 22:26 -------
Subject: Bug 11754

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	objc-improvements-branch
Changes by:	pinskia@gcc.gnu.org	2003-07-31 22:26:54

Modified files:
	gcc/objc       : objc-act.c 
Added files:
	gcc/testsuite/objc/execute: cascading-1.m 

Log message:
	Fix PR objc/11754
	When cascading message together under GNU runtime, GCC was sending the inner message twice,
	this patch fixes that.
	Also adds a testcase for that case.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/objc/objc-act.c.diff?cvsroot=gcc&only_with_tag=objc-improvements-branch&r1=1.179.2.2&r2=1.179.2.3
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/objc/execute/cascading-1.m.diff?cvsroot=gcc&only_with_tag=objc-improvements-branch&r1=NONE&r2=1.1.2.1

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754


pinskia at physics dot uc dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


------- Additional Comments From pinskia at physics dot uc dot edu  2003-07-31 22:29 -------
Fixed by the patch.
Thanks for finding it alexander.

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[alexander at malmberg dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754


alexander at malmberg dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|FIXED                       |


------- Additional Comments From alexander at malmberg dot org  2003-07-31 23:49 -------
Unfortunately, there's a typo in the committed fix:

+      if (!supper_flag)

should be "super_flag", not "supper_flag".

Also, it's worth noting that this doesn't apply only to cascaded messages,
although that's where I discovered it. Incorrect code will be generated when the
expression for the receiver has any kind of side effect, and pessimal code in
other cases. Eg.

[SomeClass foo] would call objc_get_class("SomeClass") twice (which is harmless)

and

[someFunction() foo] would call someFunction() twice, which has a good chance of
not being harmless

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754



------- Additional Comments From pinskia at physics dot uc dot edu  2003-07-31 23:54 -------
I fixed the typo.  I will also add more testcases for the tests you mentioned.

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754


pinskia at physics dot uc dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


------- Additional Comments From pinskia at physics dot uc dot edu  2003-07-31 23:55 -------
I fixed the typo.

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[cvs-commit at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754



------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-07-31 23:59 -------
Subject: Bug 11754

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	objc-improvements-branch
Changes by:	pinskia@gcc.gnu.org	2003-07-31 23:59:04

Added files:
	gcc/testsuite/objc/execute: function-message-1.m 

Log message:
	new test case for PR objc/11754

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/objc/execute/function-message-1.m.diff?cvsroot=gcc&only_with_tag=objc-improvements-branch&r1=NONE&r2=1.1.2.1

[Bug objc/11754] [objc-improvements-branch] receiver is evaluated twice when passing messages with the gnu runtime

[dhazeghi at yahoo dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11754