Hi again,
When trying to instrument switch statements (this time), by adding calls
to trace() in every branch and after the switch, I got some Fatal errors
because of inconsistent paths.
The rule I'm trying is:
--- trace.c
@@ statement s; @@
switch(...) {
case ...:
+mwtrace();/*case*/
s
... }
+mwtrace();/*endsw*/
@@ statement s; @@
switch(...) {
default:
+mwtrace();/*def*/
s
... }
I applied this patch to both of the following two files:
--- contbreak.c:
short GetInfoDestInf() {
short i = 0;
for(i=0; i<10; i++) {
switch(i) {
case 1:
printf("i=1\n");
break;
default:
printf("default\n");
continue;
break;
}
printf("for body\n");
}
return 0;
}
--- ifdefcase.c
short GetInfoOcc(long lTypeArray)
{
switch(lTypeArray)
{
case C_RINA_ST_BLK :
sRetour = 0;
break;
#ifdef INA_UNIX
case C_RINA_MES_ST_LST_THEME :
sRetour = 1;
break;
#endif
default:
sRetour = -1;
break;
}
return sRetour;
}
As a result, I get in both cases a fatal error:
Fatal error: exception Failure("rule starting on line 1: node 13:
[endswitch][1,2,4,5,6] in GetInfoDestInf reachable by inconsistent
control-flow paths")
Fatal error: exception Failure("rule starting on line 1: node 18:
sRetour = ... ;[1,2,3,4,8,9] in GetInfoOcc reachable by inconsistent
control-flow paths")
By plaing a bit with the examples, I saw that:
- in contbreak.c, the problem comes from the "continue" followed by the
"break", because commenting either one eliminates the error
- in ifdefcase.c, the problem comes from the case within #if/#endif,
because taking this out eliminate the error.
To avoid the problem, I used the option --allow-inconsistent-paths, and
this works for both cases, with the results I'm expecting. So this is
ok.
However, as the manual says that this option is "unsafe", my question
is: do I risk anything on this kind of local syntactic transformations?
I mean, when all the rules have to be applied independently of the
control flow graph?
Cheers,
Nic.
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