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  • #1271

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.

Attachments

  • incorrect_sliced_value.tgz
  • small.tgz
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