Example: provenance_multiple_2_global.c

#include <stdio.h>
int y[2], x[2];
int main() {
int *p = &(x[0]) + (&(y[1])-&(y[0]));
*p = 11; // is this free of undefined behaviour?
printf("x[1]=%d *p=%d\n",x[1],*p);
return 0;
}
[link to test in Cerberus and Compiler Explorer]

Experimental data (what does this mean?)

gcc-8.1-O0 x[1]=11 *p=11
gcc-8.1-O2 x[1]=11 *p=11
gcc-8.1-O3 x[1]=11 *p=11
gcc-8.1-O2-no-strict-aliasing x[1]=11 *p=11
gcc-8.1-O3-no-strict-aliasing x[1]=11 *p=11
clang-6.0-O0 x[1]=11 *p=11
clang-6.0-O2 x[1]=11 *p=11
clang-6.0-O3 x[1]=11 *p=11
clang-6.0-O2-no-strict-aliasing x[1]=11 *p=11
clang-6.0-O3-no-strict-aliasing x[1]=11 *p=11
clang-6.0-UBSAN x[1]=11 *p=11
clang-6.0-ASAN x[1]=11 *p=11
clang-6.0-MSAN x[1]=11 *p=11
icc-19-O0 x[1]=11 *p=11
icc-19-O2 x[1]=11 *p=11
icc-19-O3 x[1]=11 *p=11
icc-19-O2-no-strict-aliasing x[1]=11 *p=11
icc-19-O3-no-strict-aliasing x[1]=11 *p=11
cerberus-concrete BEGIN EXEC[0]
Defined {value: "Specified(0)", stdout: "x[1]=11 *p=11\n", blocked: "false"}
END EXEC[0]
Time spent: 0.021511 seconds
cerberus-symbolic exit codes: compile 0 / execute 1 cerberus: internal error, uncaught exception:
Failure("Mem.apply_shift_path_element: symbolic array index ==> IV(Prov_none, IVop(+, IVconcrete(0), IVptrdiff(signed int[2], (PVbase(3, {y}), [SPE_array(signed int,IVconcrete(1))]), (PVbase(3, {y}), [SPE_array(signed int,IVconcrete(0))]))))")

gcc-4.9-shadowprov x[1]=11 *p=11
CHERI:MIPS-O0 x[1]=11 *p=11
CHERI:MIPS-O2 x[1]=11 *p=11
CHERI:MIPS-O2-no-strict-aliasing x[1]=11 *p=11
CHERI:CHERI-O0-uintcap-addr-exact-equals x[1]=11 *p=11
CHERI:CHERI-O2-uintcap-addr-exact-equals x[1]=11 *p=11
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr-exact-equals x[1]=11 *p=11
CHERI:CHERI-O0-uintcap-offset-exact-equals x[1]=11 *p=11
CHERI:CHERI-O2-uintcap-offset-exact-equals x[1]=11 *p=11
CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset-exact-equals x[1]=11 *p=11
CHERI:CHERI-O0-uintcap-addr x[1]=11 *p=11
CHERI:CHERI-O2-uintcap-addr x[1]=11 *p=11
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr x[1]=11 *p=11
CHERI:CHERI-O0-uintcap-offset x[1]=11 *p=11
CHERI:CHERI-O2-uintcap-offset x[1]=11 *p=11
CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset x[1]=11 *p=11
RV-Match exit codes: compile 0 / execute 1
ch2o x[1]=11 *p=11
compcert-3.2 x[1]=11 *p=11
compcert-3.2-O x[1]=11 *p=11
compcert-3.2-interp Time 0: calling main()
--[step_internal_function]-->
Time 1: in function main, statement
p = &*(. + 0) + (&*(. + .) - &*(. + .));
*p = 11;
printf(__stringlit_1, *(. + 1), *p);
return 0;
return 0;
--[step_seq]-->
Time 2: in function main, statement
p = &*(. + 0) + (&*(. + .) - &*(. + .));
*p = 11;
printf(__stringlit_1, *(. + 1), *p);
return 0;
--[step_seq]-->
Time 3: in function main, statement p = &*(. + 0) + (&*(. + .) - &*(. + .));
--[step_do_1]-->
Time 4: in function main, expression p = &*(. + 0) + (&*(. + .) - &*(. + .))
--[red_var_local]-->
Time 5: in function main, expression
<loc p> = &*(. + 0) + (&*(. + .) - &*(. + .))
--[red_var_global]-->
Time 6: in function main, expression
<loc p> = &*(. + 0) + (&*(. + .) - &*(. + .))
--[red_rvalof]-->
Time 7: in function main, expression
<loc p> = &*(<ptr x> + 0) + (&*(. + .) - &*(. + .))
--[red_binop]-->
Time 8: in function main, expression
<loc p> = &*<ptr x> + (&*(. + .) - &*(. + .))
--[red_deref]-->
Time 9: in function main, expression
<loc p> = &<loc x> + (&*(. + .) - &*(. + .))
--[red_addrof]-->
Time 10: in function main, expression
<loc p> = <ptr x> + (&*(. + .) - &*(. + .))
--[red_var_global]-->
Time 11: in function main, expression
<loc p> = <ptr x> + (&*(. + .) - &*(. + .))
--[red_rvalof]-->
Time 12: in function main, expression
<loc p> = <ptr x> + (&*(. + .) - &*(. + .))
--[red_binop]-->
Time 13: in function main, expression
<loc p> = <ptr x> + (&*<ptr y+4> - &*(. + .))
--[red_deref]-->
Time 14: in function main, expression
<loc p> = <ptr x> + (&<loc y+4> - &*(. + .))
--[red_addrof]-->
Time 15: in function main, expression
<loc p> = <ptr x> + (<ptr y+4> - &*(. + .))
--[red_var_global]-->
Time 16: in function main, expression
<loc p> = <ptr x> + (<ptr y+4> - &*(. + .))
--[red_rvalof]-->
Time 17: in function main, expression
<loc p> = <ptr x> + (<ptr y+4> - &*(. + .))
--[red_binop]-->
Time 18: in function main, expression
<loc p> = <ptr x> + (<ptr y+4> - &*<ptr y>)
--[red_deref]-->
Time 19: in function main, expression
<loc p> = <ptr x> + (<ptr y+4> - &<loc y>)
--[red_addrof]-->
Time 20: in function main, expression
<loc p> = <ptr x> + (<ptr y+4> - <ptr y>)
--[red_binop]-->
Time 21: in function main, expression <loc p> = <ptr x> + 1
--[red_binop]-->
Time 22: in function main, expression <loc p> = <ptr x+4>
--[red_assign]-->
Time 23: in function main, expression <ptr x+4>
--[step_do_2]-->
Time 24: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 25: in function main, statement
*p = 11; printf(__stringlit_1, *(. + 1), *p); return 0;
--[step_seq]-->
Time 26: in function main, statement *p = 11;
--[step_do_1]-->
Time 27: in function main, expression *p = 11
--[red_var_local]-->
Time 28: in function main, expression *<loc p> = 11
--[red_rvalof]-->
Time 29: in function main, expression *<ptr x+4> = 11
--[red_deref]-->
Time 30: in function main, expression <loc x+4> = 11
--[red_assign]-->
Time 31: in function main, expression 11
--[step_do_2]-->
Time 32: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 33: in function main, statement
printf(__stringlit_1, *(. + 1), *p); return 0;
--[step_seq]-->
Time 34: in function main, statement printf(__stringlit_1, *(. + 1), *p);
--[step_do_1]-->
Time 35: in function main, expression printf(__stringlit_1, *(. + 1), *p)
--[red_var_global]-->
Time 36: in function main, expression
printf(<loc __stringlit_1>, *(. + 1), *p)
--[red_rvalof]-->
Time 37: in function main, expression
printf(<ptr __stringlit_1>, *(. + 1), *p)
--[red_var_global]-->
Time 38: in function main, expression
printf(<ptr __stringlit_1>, *(. + 1), *p)
--[red_rvalof]-->
Time 39: in function main, expression
printf(<ptr __stringlit_1>, *(<ptr x> + 1), *p)
--[red_binop]-->
Time 40: in function main, expression
printf(<ptr __stringlit_1>, *<ptr x+4>, *p)
--[red_deref]-->
Time 41: in function main, expression
printf(<ptr __stringlit_1>, <loc x+4>, *p)
--[red_rvalof]-->
Time 42: in function main, expression printf(<ptr __stringlit_1>, 11, *p)
--[red_var_local]-->
Time 43: in function main, expression
printf(<ptr __stringlit_1>, 11, *<loc p>)
--[red_rvalof]-->
Time 44: in function main, expression
printf(<ptr __stringlit_1>, 11, *<ptr x+4>)
--[red_deref]-->
Time 45: in function main, expression
printf(<ptr __stringlit_1>, 11, <loc x+4>)
--[red_rvalof]-->
Time 46: in function main, expression printf(<ptr __stringlit_1>, 11, 11)
x[1]=11 *p=11
Time 46: observable event: extcall printf(& __stringlit_1, 11,
11) -> 14
--[red_builtin]-->
Time 47: in function main, expression 14
--[step_do_2]-->
Time 48: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 49: in function main, statement return 0;
--[step_return_1]-->
Time 50: in function main, expression 0
--[step_return_2]-->
Time 51: returning 0
Time 51: program terminated (exit code = 0)
In file included from provenance_multiple_2_global.c:1:
In file included from /usr/include/stdio.h:64:
In file included from /usr/include/_stdio.h:68:
/usr/include/sys/cdefs.h:81:2: warning: "Unsupported compiler detected" [-W#warnings]
#warning "Unsupported compiler detected"
^
1 warning generated.