Example: provenance_equality_uintptr_t_global_xy.c

#include <stdio.h>
#include <inttypes.h> 
int x=1, y=2;
int main() {
  uintptr_t p = (uintptr_t)(&x + 1);
  uintptr_t q = (uintptr_t)&y;
  printf("Addresses: p=%" PRIxPTR " q=%" PRIxPTR "\n",
         p,q);
  _Bool b = (p==q);
  // can this be false even with identical addresses?
  printf("(p==q) = %s\n", b?"true":"false");
  return 0;
}

Experimental data (what does this mean?)

gcc-8.1-O0
 
Addresses: p=6009b4 q=6009b4
(p==q) = true

gcc-8.1-O2
 
Addresses: p=6009a0 q=600998
(p==q) = false

gcc-8.1-O3
 
Addresses: p=6009a0 q=600998
(p==q) = false

gcc-8.1-O2-no-strict-aliasing
 
Addresses: p=6009a0 q=600998
(p==q) = false

gcc-8.1-O3-no-strict-aliasing
 
Addresses: p=6009a0 q=600998
(p==q) = false

clang-6.0-O0
 
Addresses: p=60103c q=60103c
(p==q) = true

clang-6.0-O2
 
Addresses: p=60103c q=60103c
(p==q) = true

clang-6.0-O3
 
Addresses: p=60103c q=60103c
(p==q) = true

clang-6.0-O2-no-strict-aliasing
 
Addresses: p=60103c q=60103c
(p==q) = true

clang-6.0-O3-no-strict-aliasing
 
Addresses: p=60103c q=60103c
(p==q) = true

clang-6.0-UBSAN
 
Addresses: p=631b54 q=631b54
(p==q) = true

clang-6.0-ASAN
 
Addresses: p=716b64 q=716ba0
(p==q) = false

clang-6.0-MSAN
 
Addresses: p=6b7af4 q=6b7af4
(p==q) = true

icc-19-O0
 
Addresses: p=600ae4 q=600ae4
(p==q) = true

icc-19-O2
 
Addresses: p=6046c4 q=6046c4
(p==q) = true

icc-19-O3
 
Addresses: p=6046c4 q=6046c4
(p==q) = true

icc-19-O2-no-strict-aliasing
 
Addresses: p=6046c4 q=6046c4
(p==q) = true

icc-19-O3-no-strict-aliasing
 
Addresses: p=6046c4 q=6046c4
(p==q) = true

cerberus-concrete
 
BEGIN EXEC[0]
Defined {value: "Specified(0)", stdout: "Addresses: p=3c q=3c\n(p==q) = true\n", blocked: "false"}
END EXEC[0]
Time spent: 0.020401 seconds

cerberus-symbolic
 
BEGIN EXEC[0]
Undefined [other_location(Core parser)]{id: [DUMMY(rev_listFromStr_aux)]}
END EXEC[0]
Time spent: 0.078452 seconds

gcc-4.9-shadowprov
 
Addresses: p=414140 q=414138
(p==q) = false

CHERI:MIPS-O0
 
Addresses: p=30024 q=30024
(p==q) = true

CHERI:MIPS-O2
 
Addresses: p=30024 q=30024
(p==q) = true

CHERI:MIPS-O2-no-strict-aliasing
 
Addresses: p=30024 q=30024
(p==q) = true

CHERI:CHERI-O0-uintcap-addr-exact-equals
 
Addresses: p=4 q=0
(p==q) = false

CHERI:CHERI-O2-uintcap-addr-exact-equals
 
Addresses: p=4 q=0
(p==q) = false

CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr-exact-equals
 
Addresses: p=4 q=0
(p==q) = false

CHERI:CHERI-O0-uintcap-offset-exact-equals
 
Addresses: p=4 q=0
(p==q) = false

CHERI:CHERI-O2-uintcap-offset-exact-equals
 
Addresses: p=4 q=0
(p==q) = false

CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset-exact-equals
 
Addresses: p=4 q=0
(p==q) = false

CHERI:CHERI-O0-uintcap-addr
 
Addresses: p=4 q=0
(p==q) = true

CHERI:CHERI-O2-uintcap-addr
 
Addresses: p=4 q=0
(p==q) = true

CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr
 
Addresses: p=4 q=0
(p==q) = true

CHERI:CHERI-O0-uintcap-offset
 
Addresses: p=4 q=0
(p==q) = true

CHERI:CHERI-O2-uintcap-offset
 
Addresses: p=4 q=0
(p==q) = true

CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset
 
Addresses: p=4 q=0
(p==q) = true

RV-Match
 
exit codes: compile 0 / execute 1

ch2o
 
provenance_equality_uintptr_t_global_xy.c:2:10: fatal error: inttypes.h: No such file or directory
 #include <inttypes.h>
          ^~~~~~~~~~~~
compilation terminated.

compcert-3.2
 
Addresses: p=60103c q=60103c
(p==q) = true

compcert-3.2-O
 
Addresses: p=60103c q=60103c
(p==q) = true

compcert-3.2-interp
 
Time 0: calling main()
--[step_internal_function]-->
Time 1: in function main, statement
  p = (unsigned int) (&x + 1);
  q = (unsigned int) &y;
  printf(__stringlit_1, p, q);
  b = p == q;
  printf(__stringlit_4, b ? __stringlit_3 : __stringlit_2);
  return 0;
  return 0;
--[step_seq]-->
Time 2: in function main, statement
  p = (unsigned int) (&x + 1);
  q = (unsigned int) &y;
  printf(__stringlit_1, p, q);
  b = p == q;
  printf(__stringlit_4, b ? __stringlit_3 : __stringlit_2);
  return 0;
--[step_seq]-->
Time 3: in function main, statement p = (unsigned int) (&x + 1);
--[step_do_1]-->
Time 4: in function main, expression p = (unsigned int) (&x + 1)
--[red_var_local]-->
Time 5: in function main, expression <loc p> = (unsigned int) (&x + 1)
--[red_var_global]-->
Time 6: in function main, expression <loc p> = (unsigned int) (&<loc x> + 1)
--[red_addrof]-->
Time 7: in function main, expression <loc p> = (unsigned int) (<ptr x> + 1)
--[red_binop]-->
Time 8: in function main, expression <loc p> = (unsigned int) <ptr x+4>
--[red_cast]-->
Time 9: in function main, expression <loc p> = <ptr x+4>
--[red_assign]-->
Time 10: in function main, expression <ptr x+4>
--[step_do_2]-->
Time 11: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 12: in function main, statement
  q = (unsigned int) &y;
  printf(__stringlit_1, p, q);
  b = p == q;
  printf(__stringlit_4, b ? __stringlit_3 : __stringlit_2);
  return 0;
--[step_seq]-->
Time 13: in function main, statement q = (unsigned int) &y;
--[step_do_1]-->
Time 14: in function main, expression q = (unsigned int) &y
--[red_var_local]-->
Time 15: in function main, expression <loc q> = (unsigned int) &y
--[red_var_global]-->
Time 16: in function main, expression <loc q> = (unsigned int) &<loc y>
--[red_addrof]-->
Time 17: in function main, expression <loc q> = (unsigned int) <ptr y>
--[red_cast]-->
Time 18: in function main, expression <loc q> = <ptr y>
--[red_assign]-->
Time 19: in function main, expression <ptr y>
--[step_do_2]-->
Time 20: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 21: in function main, statement
  printf(__stringlit_1, p, q);
  b = p == q;
  printf(__stringlit_4, b ? __stringlit_3 : __stringlit_2);
  return 0;
--[step_seq]-->
Time 22: in function main, statement printf(__stringlit_1, p, q);
--[step_do_1]-->
Time 23: in function main, expression printf(__stringlit_1, p, q)
--[red_var_global]-->
Time 24: in function main, expression printf(<loc __stringlit_1>, p, q)
--[red_rvalof]-->
Time 25: in function main, expression printf(<ptr __stringlit_1>, p, q)
--[red_var_local]-->
Time 26: in function main, expression printf(<ptr __stringlit_1>, <loc p>, q)
--[red_rvalof]-->
Time 27: in function main, expression
  printf(<ptr __stringlit_1>, <ptr x+4>, q)
--[red_var_local]-->
Time 28: in function main, expression
  printf(<ptr __stringlit_1>, <ptr x+4>, <loc q>)
--[red_rvalof]-->
Time 29: in function main, expression
  printf(<ptr __stringlit_1>, <ptr x+4>, <ptr y>)
Addresses: p=<int argument expected> q=<int argument expected>

Time 29: observable event: extcall printf(& __stringlit_1, & x+4, & y) -> 63
--[red_builtin]-->
Time 30: in function main, expression 63
--[step_do_2]-->
Time 31: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 32: in function main, statement
  b = p == q;
  printf(__stringlit_4, b ? __stringlit_3 : __stringlit_2);
  return 0;
--[step_seq]-->
Time 33: in function main, statement b = p == q;
--[step_do_1]-->
Time 34: in function main, expression b = p == q
--[red_var_local]-->
Time 35: in function main, expression <loc b> = p == q
--[red_var_local]-->
Time 36: in function main, expression <loc b> = <loc p> == q
--[red_rvalof]-->
Time 37: in function main, expression <loc b> = <ptr x+4> == q
--[red_var_local]-->
Time 38: in function main, expression <loc b> = <ptr x+4> == <loc q>
--[red_rvalof]-->
Time 39: in function main, expression <loc b> = <ptr x+4> == <ptr y>
Stuck state: in function main, expression <loc b> = <ptr x+4> == <ptr y>
Stuck subexpression: <ptr x+4> == <ptr y>
ERROR: Undefined behavior
In file included from provenance_equality_uintptr_t_global_xy.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.