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[Frama-c-discuss] RE : [wp] type conversion check is less strict than Jessie?

Hi,

This is because you are casting a constant int into a pointer, which makes a valid physical address.
However, you can not do pointer arithmetics on such values, say, you **can not prove** that (int *) 0x100 shifted by one (on 64-bit machine) leads to (int *) 0x108.

By the way, I'm surprise by the output of WP you report here. Which version are you using ?
I suggest you to move to Fluorine, where the memory model of wp offers more options on pointers and casts.

Regards.

________________________________
De : frama-c-discuss-bounces at lists.gforge.inria.fr [frama-c-discuss-bounces at lists.gforge.inria.fr] de la part de Xiao-lei Cui [x_cui at hotmail.com]
Date d'envoi : lundi 9 d?cembre 2013 07:02
? : frama-c-discuss at lists.gforge.inria.fr
Objet : [Frama-c-discuss] [wp] type conversion check is less strict than Jessie?


Hi all,
   I used Jessie plug-in before I tried wp.
   Jessie will not tolerate the following situation where a int constant is to be converted to unsigned int*
--------------------------------------------------------------
#define ARTAR                ( (unsigned int * )0x01f800e0) )
unsigned int  sr;
sr = ARTAR;
--------------------------------------------------------------
[jessie] failure: Casting from type int to type struct unsigned_intP * not allowed

However, as I run wp plug-in over the same C file:
$ frama-c  -pp-annot  -wp -wp-rte -wp-prover why3ide file.c

I did not get any complaints from wp, and the VCs( very simple though) seems proved already:
[wp] Running WP plugin...
[wp] Collecting axiomatic usage
[rte] annotating function SerialBaud
[wp] Goal typed_SB_b1_post : trivial
[wp] Goal typed_SB_b2_post : trivial

Jessie and WP behaves so differently in type conversion check (for this case) ? Is it that type check is turned off by default in WP? or I did not invoke wp in the correct way..

Any hints would be appreciated. Thanks..

cheers
xiao-lei


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