gcc accumulates instead of overlaying frame variables

gcc accumulates instead of overlaying frame variables

[Michael LeBlanc]

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I am submitting this as instructed, as a last resort, because

(1) I can't figure out how to attach files in the bugzilla page; and
(2) I can't find a gccbug script in a 3.3 source package.

So here are the things from

	gcc -v -save-temps x.c f.c

$ tar tvf gnu.tar
drwxrwxr-x leblanc/leblanc   0 2004-05-12 12:50:24 ./
-rw-rw-r-- leblanc/leblanc 152 2004-05-12 12:12:33 ./x.c
-rw-rw-r-- leblanc/leblanc  76 2004-05-12 12:10:54 ./f.c
-rw-rw-r-- leblanc/leblanc 207 2004-05-12 12:49:20 ./x.i
-rw-rw-r-- leblanc/leblanc 367 2004-05-12 12:49:20 ./x.s
-rw-rw-r-- leblanc/leblanc 134 2004-05-12 12:49:20 ./f.i
-rw-rw-r-- leblanc/leblanc 437 2004-05-12 12:49:20 ./f.s
-rw-rw-r-- leblanc/leblanc 2776 2004-05-12 12:49:20 ./stderr

See the source down below.  SUN and Metaware believe, correctly, that 
the
two blocks overlay each other in the final stack frame.  GCC adds them
together.  It looks like this mistake has been around for quite a while.

(1) on Solaris

     SUN
         % /opt/SUNWspro/bin/cc -V
         cc: Sun WorkShop 6 2000/04/07 C 5.1

         % /opt/SUNWspro/bin/cc x.c f.c
         x.c:
         f.c:

         % ./a.out
         frame is about 612 bytes
         frame is about 612 bytes

     HighC
         % hc x.c f.c -Hcopyr
         x.c:
         MetaWare High C Compiler R2.8   Serial 1-SKY-799999.
         (c) Copyright 1987-98, MetaWare Incorporated
         f.c:
         w "f.c",L4/C3(#291):    printf: Function called but not 
declared.
         No errors   1 warning

         % ./a.out
         frame is about 608 bytes
         frame is about 608 bytes

     GCC
         % gcc -v
         Reading specs from 
/usr/local/lib/gcc-lib/sparc-sun-solaris2.8/2.95.3/specs
         gcc version 2.95.3 20010315 (release)

         % gcc x.c f.c

         % ./a.out
         frame is about 1136 bytes
         frame is about 624 bytes
(2) on YDL 3.0

         $ gcc -v
         ...
         gcc version 3.3

         $ gcc x.c f.c

         $ ./a.out
         frame is about 547 bytes
         frame is about 1059 bytes

SOURCE

         % cat f.c
         void foo(char *p)
         {
           char x;
           printf("frame is about %d bytes\n",p-&x);
         }

         % cat x.c

         #define N 512

         extern void foo(char *p);

         int main()
         {
           {
             char x[N];
             foo(&x[N-1]);
           }
           {
             char x[N];
             foo(&x[N-1]);
           }
           return 0;
         }


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Re: gcc accumulates instead of overlaying frame variables

[Andrew Pinski]

On May 12, 2004, at 13:16, Michael LeBlanc wrote:

> I am submitting this as instructed, as a last resort, because
>
> (1) I can't figure out how to attach files in the bugzilla page; and
> (2) I can't find a gccbug script in a 3.3 source package.
>
> So here are the things from
>
> 	gcc -v -save-temps x.c f.c
>
> $ tar tvf gnu.tar
> drwxrwxr-x leblanc/leblanc   0 2004-05-12 12:50:24 ./
> -rw-rw-r-- leblanc/leblanc 152 2004-05-12 12:12:33 ./x.c
> -rw-rw-r-- leblanc/leblanc  76 2004-05-12 12:10:54 ./f.c
> -rw-rw-r-- leblanc/leblanc 207 2004-05-12 12:49:20 ./x.i
> -rw-rw-r-- leblanc/leblanc 367 2004-05-12 12:49:20 ./x.s
> -rw-rw-r-- leblanc/leblanc 134 2004-05-12 12:49:20 ./f.i
> -rw-rw-r-- leblanc/leblanc 437 2004-05-12 12:49:20 ./f.s
> -rw-rw-r-- leblanc/leblanc 2776 2004-05-12 12:49:20 ./stderr
>
> See the source down below.  SUN and Metaware believe, correctly, that 
> the
> two blocks overlay each other in the final stack frame.  GCC adds them
> together.  It looks like this mistake has been around for quite a 
> while.



This is not a bug per say really but it is bug 9997 anyways.

Thanks,
Andrew Pinski

Re: gcc accumulates instead of overlaying frame variables

[Jim Wilson]

Michael LeBlanc wrote:
> (1) I can't figure out how to attach files in the bugzilla page; and

Create a bug report without a testcase, wait for the confirmation 
message, then visit the URL for the bug and click on the link "Create a 
New Attachment".  Admittedly this is not ideal, but it does work.

> (2) I can't find a gccbug script in a 3.3 source package.

The gccbug script is created when you build gcc, from the gccbug.in 
source file.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com