[Bug c/16000] New: for h8 targets variadic functions are not working properly

[Bug c/16000] New: for h8 targets variadic functions are not working properly

[manishas at kpitcummins dot com]

Consider the  attached test case for H8 target in which variadic function is 
declared to take variable number of  arguments but in the definition fixed 
number of arguments are used.  This is allowed in gcc as per document in  
http://www.gnu.org/software/libc/manual/html_node/Why-Variadic.html#Why%
20Variadic

Following code does not pass arguments properly to the function. The variadic 
function gives 
wrong results because  parameters are passed on stack and the function is 
expects parameters in registers. Which can be observed from the following 
assembly code
	
mov.w	#3,r2
mov.l er2, @-er7 // push arg3 on stack
sub.l	er2,er2
add.b	#2,r2l
mov.l er2, @-er7 // push arg2 on stack
mov.w	#1,r0 // move arg1 in er0
jsr	@_variadic_test// call variadic_test function.

The register er7 is the stack pointer. So the arguments 2 and 3 are pushed onto 
stack and argument1 is in register r0.And this is the assembler code in the 
function variadic_test immediately after the jsr instruction above is executed:

mov.l er6, @-er7 // save frame pointer
mov.l er7,er6
.
.
mov.w r0,@(-2,er6) // get arg 1 from r0
mov.l er1,@(-8,er6) // get arg 2 from er1
mov.l er2,@(-12,er6) // get arg 3 from er2


The function sets up the stack and then copies the function arguments from the 
registers r0, er1 and er2 onto the stack. But because of the different function 
declaration the registers r0, er1 and er2 do not contain the expected values.

command line for assembly code:
h8300-elf-gcc -S -ms variadic.c  main.c

command line for output file: 
h8300-elf-gcc  -o  main.out  variadic.c main.c

------------variadic.c------------------------------------

int variadic_test(int arg1, unsigned long arg2, unsigned long arg3)
{

    int           ret;


    ret = arg1 + arg2 + arg3;

    return ret;
}
----------------------------------------------------------------
------------------ main.c ----------------------------------------------
int variadic_test (int, unsigned long, ...);

int main (void)
{
    int result_varfunc;
    int result_local;

    result_local   =  1 + 2 + 3;
    result_varfunc =  variadic_test(1, 2, 3);

    if (result_local != result_varfunc)
    {
        //printf("error");

        return 0;
    }
    else
    {

        return 1;
    }
}

-- 
           Summary:  for h8 targets variadic functions are not working
                    properly
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: manishas at kpitcummins dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: windows 2000
GCC target triplet: h8


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

[Bug target/16000] for h8 targets variadic functions are not working properly

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-15 14:08 -------
What version are you using?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |target
           Keywords|                            |wrong-code
            Summary| for h8 targets variadic    |for h8 targets variadic
                   |functions are not working   |functions are not working
                   |properly                    |properly


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

[Bug target/16000] for h8 targets variadic functions are not working properly

[manishas at kpitcummins dot com]

------- Additional Comments From manishas at kpitcummins dot com  2004-06-15 14:12 -------
Subject: RE:  for h8 targets variadic functions are not working properly

gcc-3.4.0

-----Original Message-----
From: pinskia at gcc dot gnu dot org [mailto:gcc-bugzilla@gcc.gnu.org]
Sent: Tuesday, June 15, 2004 7:39 PM
To: Manisha V. Sagare
Subject: [Bug target/16000] for h8 targets variadic functions are not
working properly



------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-15 14:08 -------
What version are you using?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |target
           Keywords|                            |wrong-code
            Summary| for h8 targets variadic    |for h8 targets variadic
                   |functions are not working   |functions are not working
                   |properly                    |properly


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

------- You are receiving this mail because: -------
You reported the bug, or are watching the reporter.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

[Bug target/16000] for h8 targets variadic functions are not working properly

[graham dot stott at btinternet dot com]

------- Additional Comments From graham dot stott at btinternet dot com  2004-06-15 14:27 -------
Subject: Re:  for h8 targets variadic functions are not working properly

>Consider the  attached test case for H8 target in which variadic function is 
>declared to take variable number of  arguments but in the definition fixed 
>number of arguments are used.  This is allowed in gcc as per document in  
>http://www.gnu.org/software/libc/manual/html_node/Why-Variadic.html#Why%
>20Variadic

I think the statments made in the above link regarding variadic functions
are plainly wrong. It may work for sometimes for some targets but definately
not for all targets. The reason is the compiler may and can pass arguments
differently depending on the prototype and especially for varadic functions.

Both the declaration and definition should agree mixing them isn't going to
work.

Graham



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

Re: [Bug target/16000] for h8 targets variadic functions are not working properly

[Graham Stott]

>Consider the  attached test case for H8 target in which variadic function is 
>declared to take variable number of  arguments but in the definition fixed 
>number of arguments are used.  This is allowed in gcc as per document in  
>http://www.gnu.org/software/libc/manual/html_node/Why-Variadic.html#Why%
>20Variadic

I think the statments made in the above link regarding variadic functions
are plainly wrong. It may work for sometimes for some targets but definately
not for all targets. The reason is the compiler may and can pass arguments
differently depending on the prototype and especially for varadic functions.

Both the declaration and definition should agree mixing them isn't going to
work.

Graham

[Bug target/16000] for h8 targets variadic functions are not working properly

[bonzini at gnu dot org]

------- Additional Comments From bonzini at gnu dot org  2004-06-15 15:26 -------
Graham is right.  This is a problem in user code, unless this fails as well...

int variadic_test (int, unsigned long, unsigned long);

int main (void)
{
    int result_varfunc;
    int result_local;

    result_local   =  1 + 2 + 3;
    result_varfunc =  variadic_test(1, 2, 3);

    if (result_local != result_varfunc) {
        //printf("error");
        return 0;
    } else
        return 1;
}

Paolo

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

[Bug target/16000] for h8 targets variadic functions are not working properly

[bonzini at gnu dot org]

------- Additional Comments From bonzini at gnu dot org  2004-06-15 15:27 -------
This means that the error is in the documentation.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000

[Bug other/16000] for h8 targets variadic functions are not working properly

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-08-16 07:16 -------
The documentation in question is not GCC's.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
          Component|target                      |other
           Keywords|wrong-code                  |documentation
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16000