Sliced program computes value different from original (csmith)
ID0000781: This issue was created automatically from Mantis Issue 781. Further discussion may take place here.
| Id | Project | Category | View | Due Date | Updated |
|---|---|---|---|---|---|
| ID0000781 | Frama-C | Plug-in > from | public | 2011-04-11 | 2014-02-12 |
| Reporter | pascal | Assigned To | pascal | Resolution | fixed |
| Priority | normal | Severity | minor | Reproducibility | have not tried |
| Platform | - | OS | - | OS Version | - |
| Product Version | Frama-C GIT, precise the release id | Target Version | - | Fixed in Version | Frama-C Nitrogen-20111001 |
Description :
The program does not contain undefined behaviors in the sense of the value analysis, as checked by ~/ppc/bin/toplevel.opt -val -slevel 5000 -cpp-command "gcc -C -E -I runtime " s.11114014.1.c -no-results -machdep x86_64
But, when compiling and executing the sliced program, the number displayed is different from the number displayed by the original program.
cuoq@ns61143:/csmith-2.0.0$ gcc -I runtime s.11114014.1.c -o s1
s.11114014.1.c: In function ‘func_59’:
s.11114014.1.c:448: warning: comparison of distinct pointer types lacks a cast
s.11114014.1.c: In function ‘func_93’:
s.11114014.1.c:895: warning: large integer implicitly truncated to unsigned type
cuoq@ns61143:/csmith-2.0.0$ ./s1
[value] Called Frama_C_show_each({3932636802; })
cuoq@ns61143:/csmith-2.0.0$ gcc -I runtime s.11114014.1.s.c -o s2
cuoq@ns61143:/csmith-2.0.0$ ./s2
[value] Called Frama_C_show_each({1079028560; })
The sliced program was obtained using 12793+patch from bug report 780, with the command:
~/ppc/bin/toplevel.opt -val-signed-overflow-alarms s.11114014.1.c -cpp-command "gcc -C -E -I. -I runtime " -machdep x86_64 -slice-calls printf -slevel 5000 -slevel-function crc32_gentab:0 -then-on 'Slicing export' -no-slice-force -no-val -print -ocode s...s.c
Additional Information :
I am in a good position to know that these big random programs can be a pain to debug. It is possible to wait for a smaller problematic program to come along.
I have quite thoroughly tested the value analysis on these random generated programs earlier. I would have liked to be more progressive and now check building blocks of the slicing, but I do not know what to use as oracle then. Only the slicing at the top of the pyramid offers a testable interface again.
Take it easy, it's only random programs.
I should replace the variadic printf by something less variadic, just in case.