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Bug 39781 - gnat-5.0_pre20031005 fails to check range contstraints in some situations
Summary: gnat-5.0_pre20031005 fails to check range contstraints in some situations
Status: RESOLVED INVALID
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: [OLD] Development (show other bugs)
Hardware: All All
: High normal (vote)
Assignee: Gentoo Linux bug wranglers
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2004-01-29 10:07 UTC by Christian Apolloni
Modified: 2004-01-29 10:28 UTC (History)
0 users

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Package list:
Runtime testing required: ---

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Description Christian Apolloni 2004-01-29 10:07:22 UTC 
In some situations gnat fails to check range constraints of the type of a 
variable, allowing it to get a value out of the (supposed) allowed range too.

Example:

with    ada.integer_text_io;
use     ada.integer_text_io;

procedure miotest is

        n : integer := integer'last;

begin
        while n > 0 loop
                n := n + 1;
        end loop;
        put(n);

end miotest;

./miotest
-2147483648

This should exit with CONSTRAINT_ERROR when it tries to do n := n + 1. Instead 
it returns -2147483648. The same appens with a variable of type natural, obtaining in the end a natural variable containing a negative integer.

If n := n + 1 is tried without the loop, the compiler correctly warns that the 
CONSTRAINT_ERROR would be raised upon execution, as it happens:

with    ada.integer_text_io;
use     ada.integer_text_io;

procedure miotest2 is

        n : integer := integer'last;

begin
        n := n + 1;
        put(n);

end miotest2;

gnatmake miotest2
gnatgcc -c miotest2.adb
miotest2.adb:9:16: warning: value not in range of type "Standard.Integer"
miotest2.adb:9:16: warning: "Constraint_Error" will be raised at run time
gnatbind -x miotest2.ali
gnatlink miotest2.ali

./miotest2 

raised CONSTRAINT_ERROR : miotest2.adb:9 range check failed


emerge info
Portage 2.0.50_pre20 (default-x86-1.4, gcc-3.3.2, glibc-2.3.3_pre20040117-r0, 2.   6.2-rc2)
=================================================================
System uname: 2.6.2-rc2 i686 Intel(R) Pentium(R) 4 CPU 2.40GHz
Gentoo Base System version 1.4.3.12
Autoconf: sys-devel/autoconf-2.59
Automake: sys-devel/automake-1.7.8
ACCEPT_KEYWORDS="x86 ~x86"
AUTOCLEAN="yes"
CFLAGS="-march=pentium4 -mfpmath=sse -Os -pipe"
CHOST="i686-pc-linux-gnu"
COMPILER="gcc3"
CONFIG_PROTECT="/etc /usr/X11R6/lib/X11/xkb /usr/kde/2/share/config /usr/kde/3/s   hare/config /usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/   dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/c   onfig/ /usr/share/texmf/xdvi/ /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/gconf /etc/env.d"
CXXFLAGS="-march=pentium4 -mfpmath=sse -Os -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoaddcvs ccache sandbox"
GENTOO_MIRRORS="ftp://sunsite.cnlab-switch.ch/mirror/gentoo/ http://gentoo.orego   nstate.edu http://www.ibiblio.org/pub/Linux/distributions/gentoo"
MAKEOPTS="-j2"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="S3TC X aalib alsa apache2 avi caps cdr crypt cups dga dv dvb dvd encode foo   maticdb gif gimpprint gpgme gpm gtk gtk2 imlib ipv6 java jpeg maildir mmx mozill   a moznocompose moznoirc moznomail mpeg ncurses nls nptl oggvorbis opengl pam pdf   lib perl plotutils png pnp python quicktime readline samba sasl sdl snmp sse ssl    tcpd tetex tiff truetype usb wmf wxwindows x86 xchattext xml xml2 xmms xv zlib"
Comment 1 Christian Apolloni 2004-01-29 10:28:08 UTC 
Sorry, I forgot the -gnato option, it seems to solve the problem.

BTW I wonder why out of the loop it worked...