Re: New gpc snapshot released: New bugs

10 Sep 2007

      Waldek Hebisch a écrit:
...
I have put a new gpc snapshot at:
http://www.math.uni.wroc.pl/~hebisch/gpc-20070904.tar.bz2
When recompiling my programs with djgpp built snapshot, both
with gcc 3.4.4 and gcc 4.1.2 backends (both uploaded)
I have found two new bugs (not present with gpc 20060325 /gcc 3.4.4)

Reducing to smallest possible test programs they are

1/ ======================================================

Problem with recursive definition or operators

Occurs for both backends

Two  programs display the bug

---------------------------------------------------------

program powrecur;

var r: real;

operator power(r: real; n:integer) y: real;
begin
    if n < 0 then y := 1 / (r power (0-n))
    else y := r pow n
end;

begin
    r := 10;
    if abs ( r power(-2) - r pow (-2) ) < epsreal then
       write('OK')
    else
       write('failed')
end.

--------------------------------------------------------------

program minrecur;

var i,j: integer;

operator minus (a,b: integer) = y: integer;
begin
    if b < 0 then y := -( (0-a) minus (0-b) )
    else y := a - b
end;

begin
    i := -10;
    j := -10;
    if i minus j = 0 then
       write('OK')
    else
       write('failed')
end.

---------------------------------------------------------------

They give similar error messages

minrecur.pas: In operator `minus (integer, integer)':
minrecur.pas:7: error: invalid use of operator `minus'

Notice that (0-n) (0-a) (0-b) instead of (-n) (-a) (-b)
where necessary in the previous (20060325) snapshot,
which compiles these programs (ang gives good results
with more complicated arguments).

Work around is easy, but a fix would be better.

2/ ============================================================

Occurs only with 4.1.2 backend.

The test program is composed of two files

--------------------------------------------------------------

program strg;

uses ustrg;

begin
    if  n = Un then
       write('OK')
    else
       write('failed');
end.

---------------------------------------------------

unit ustrg;

INTERFACE

function str2int(const s: string) = i : integer;

var
    Un : integer = str2int('1');
    n : integer;

IMPLEMENTATION

function str2int(const s: string) = i : integer;
begin
    ReadStr(s,i)
end;

begin
    n := str2int('1');
end.

-------------------------------------------------

The error message is

c:\lombardi\djgpp\o/ustrg.o: In function `_p__M5_Ustrg_init':
ustrg.pas:11: undefined reference to `__p__M5_Ustrg_S1_tmp_string_0'
ustrg.pas:18: undefined reference to `__p__M5_Ustrg_S1_tmp_string_0'
ustrg.pas:18: undefined reference to `__p__M5_Ustrg_S1_tmp_string_0'
ustrg.pas:11: undefined reference to `__p__M5_Ustrg_S1_tmp_string_0'
ustrg.pas:11: undefined reference to `__p__M5_Ustrg_S2_nonconstant_expr_1'
collect2: ld returned 1 exit status

-------------------------------------------------------------

it seems to occur only with this dual initialisation:
one directly in the interface
one in the initialization part of the unit.
and only with strings
changing to a given fixed length string or to a local made
(instead of internal) function WriteStr changes nothing

Hope this helps

Maurice

-- 
        Maurice Lombardi
Laboratoire de  Spectrometrie Physique,
Universite Joseph Fourier de Grenoble, BP87
38402 Saint Martin d'Heres Cedex     FRANCE
Tel: 33 (0)4 76 51 47 51
Fax: 33 (0)4 76 63 54 95
mailto:Maurice.Lombardi@ujf-grenoble.fr