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GDB does not handle functions with float args with K&R prototypes

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Information:
Type :: BUG
Status :: CLOSED
Assigned to :: Jeremy, Bennett

Description:

GDB has a problem passing args correctly to dummy function calls if that function takes a float argument, and is specified using a Kernigan & Ritchie style function prototype, rather than an ANSI prototype.

Test program:

float foo = '1';
float L;


#ifdef KR
void Fun (foo)
     float  foo;
#else
void Fun (float foo)
#endif
{
  L = foo;

}       /* Fun () */


int main ()
{
  Fun (foo);    
  return  0;

}       /* main () */

This can be compiled using the ANSI function prototype using:

or32-elf-gcc -g -mor32-newlib call-test.c

And as K&R function prototype using:

or32-elf-gcc -g -mor32-newlib -DKR call-test.c

This should be debugged with GDB, using the following commands

file a.out
target sim
load
break main
run
call Fun(foo)
print /c L

Fun should set the float global variable L to the value in the float global variable foo, which as a char is '1'. It works with the ANSI version, not the K&R version.

It seems that the K&R version effectively treats the argument as double, even though declared float. However when called as a dummy function within GDB, the argument is set up as a float.

Not clear if this is a generic GDB issue, or a fault in the OR32 function to set up a dummy call.

No one is likely to write (and hence debug) K&R code today, but there is still a lot out there, so we should support this. For now the regression is run using -DPROTOTYPES in the C flags, which means all tests are compiled using prototypes.

Jeremy

--
Tel: +44 (1590) 610184
Cell: +44 (7970) 676050
SkypeID: jeremybennett
Email: jeremy.bennett@embecosm.com
Web: www.embecosm.com

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