[RFC] Stabs parsing regression from GDB 6.6 to GDB 6.6.90

[Pierre Muller]

  There is a new problem that 
appears in 6.6.90 and was not present in 
6.6 related to the gcc
-gstabs+ option.

  If I compile the following tiny source
and try to get the type of the variable u,
I get an error, because
gdb is not able to handle the extended 
stabs generated with -gstabs+ option
(if you only use -gstabs, it works OK).

>>>Source file:
unsigned long long u;

int
main ()
{
  u = 15;
  printf("Value of u is %lu\r\n",u);
  return 0;
}
>>>End of source file

>>> Compilation
gcc -gstabs+ -o testll testll.c

>>> Launch gdb

gdb6690 ./testll
and
type 'ptyp u'

and you will receive an error...

The error is caused by:
        .stabs  "long long unsigned
int:t(0,7)=@s64;r(0,7);0000000000000;01777777777777777777777;",128,0,0,0
(With -gstabs, you don't get the '@s64;' part
which means that the size is 64 bits wide).

Note that this is parsed without generating errors:
       .stabs  "long long
int:t(0,6)=@s64;r(0,6);01000000000000000000000;0777777777777777777777;",128,
0,0,0

I added Michael Snyder in CC
because it is the only name that
I found associated with a recent change in read_huge_number
stabsread.c function. It seems that
his change changed the position
of the assignment of the variable
twos_complement_representation,
that was set in earlier version before
radix could be changed to 8 because of a leading '0'.


  Thus in 6.6 gdb, twos_complement_representation is 
always equal to zero and the problem appears
now because it is now set correctly. It seems 
that the code for twos_complement_representation
is not working properly for 13 '0' as in 'long long unsigned int' type
above.
But I am unable to understand the code correctly.

  Michael, could you please confirm my problem and 
tell us if the 

Pierre Muller
Pascal language code maintainer