Example: `pointer_arith_algebraic_properties_3_auto.c`

#include <stdio.h>
#include <inttypes.h>
int main() {
  int y[2], x[2];
  int *p=(int*)(
    (((uintptr_t)&(x[0])) + ((uintptr_t)&(y[1])))
    -((uintptr_t)&(y[0])) );
  *p = 11;  // is this free of undefined behaviour?
  //(equivalent to the &x[0]+(&(y[1])-&(y[0])) version?)
  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]
Killed {msg: MerrAccess Store [pointer_arith_algebraic_properties_3_auto.c:8:3-10] OutOfBoundPtr}
END EXEC[0]
Time spent: 0.015064 seconds

cerberus-symbolic   
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   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
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   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
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 139
A pointer (or array subscript) outside the bounds of an object:
      > in main at pointer_arith_algebraic_properties_3_auto.c:5:3

    Undefined behavior (UB-CEA1):
        see C11 section 6.5.6:8 http://rvdoc.org/C11/6.5.6
        see C11 section J.2:1 item 46 http://rvdoc.org/C11/J.2
        see CERT-C section ARR30-C http://rvdoc.org/CERT-C/ARR30-C
        see CERT-C section ARR37-C http://rvdoc.org/CERT-C/ARR37-C
        see CERT-C section STR31-C http://rvdoc.org/CERT-C/STR31-C
        see MISRA-C section 8.18:1 http://rvdoc.org/MISRA-C/8.18
        see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1

Computing pointer difference between two different objects:
      > in main at pointer_arith_algebraic_properties_3_auto.c:5:3

    Undefined behavior (UB-CEA5):
        see C11 section 6.5.6:9 http://rvdoc.org/C11/6.5.6
        see C11 section J.2:1 item 48 http://rvdoc.org/C11/J.2
        see CERT-C section ARR36-C http://rvdoc.org/CERT-C/ARR36-C
        see MISRA-C section 8.18:2 http://rvdoc.org/MISRA-C/8.18
        see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1

Conversion from an integer to non-null pointer:
      > in main at pointer_arith_algebraic_properties_3_auto.c:5:3

    Implementation defined behavior (IMPL-CCV13):
        see C11 section 6.3.2.3:5 http://rvdoc.org/C11/6.3.2.3
        see CERT section INT36-C http://rvdoc.org/CERT/INT36-C

Indeterminate value used in an expression:
      > in main at pointer_arith_algebraic_properties_3_auto.c:5:3

    Undefined behavior (UB-CEE2):
        see C11 section 6.2.4 http://rvdoc.org/C11/6.2.4
        see C11 section 6.7.9 http://rvdoc.org/C11/6.7.9
        see C11 section 6.8 http://rvdoc.org/C11/6.8
        see C11 section J.2:1 item 11 http://rvdoc.org/C11/J.2
        see CERT-C section EXP33-C http://rvdoc.org/CERT-C/EXP33-C
        see MISRA-C section 8.9:1 http://rvdoc.org/MISRA-C/8.9
        see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1

Dereferencing a null pointer:
      > in main at pointer_arith_algebraic_properties_3_auto.c:8:3

    Undefined behavior (UB-CER3):
        see C11 section 6.5.3.2:4 http://rvdoc.org/C11/6.5.3.2
        see C11 section J.2:1 item 43 http://rvdoc.org/C11/J.2
        see CERT-C section EXP34-C http://rvdoc.org/CERT-C/EXP34-C
        see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1

Execution failed (configuration dumped)

ch2o   pointer_arith_algebraic_properties_3_auto.c:2:10: fatal error: inttypes.h: No such file or directory
 #include <inttypes.h>
          ^~~~~~~~~~~~
compilation terminated.

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 = (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.);
  *p = 11;
  printf(__stringlit_1, *(. + 1), *p);
  return 0;
  return 0;
--[step_seq]-->
Time 2: in function main, statement
  p = (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.);
  *p = 11;
  printf(__stringlit_1, *(. + 1), *p);
  return 0;
--[step_seq]-->
Time 3: in function main, statement
  p = (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.);
--[step_do_1]-->
Time 4: in function main, expression
  p = (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.)
--[red_var_local]-->
Time 5: in function main, expression
  <loc p> =
    (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.)
--[red_var_local]-->
Time 6: in function main, expression
  <loc p> =
    (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.)
--[red_rvalof]-->
Time 7: in function main, expression
  <loc p> =
    (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.)
--[red_binop]-->
Time 8: in function main, expression
  <loc p> =
    (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.)
--[red_deref]-->
Time 9: in function main, expression
  <loc p> =
    (int *) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &*.)
--[red_addrof]-->
Time 10: in function main, expression
  <loc p> =
    (int *) ((unsigned int) <ptr x> + (unsigned int) &. - (unsigned int) &*.)
--[red_cast]-->
Time 11: in function main, expression
  <loc p> = (int *) (<ptr x> + (unsigned int) &. - (unsigned int) &*.)
--[red_var_local]-->
Time 12: in function main, expression
  <loc p> = (int *) (<ptr x> + (unsigned int) &. - (unsigned int) &*.)
--[red_rvalof]-->
Time 13: in function main, expression
  <loc p> = (int *) (<ptr x> + (unsigned int) &. - (unsigned int) &*.)
--[red_binop]-->
Time 14: in function main, expression
  <loc p> = (int *) (<ptr x> + (unsigned int) &. - (unsigned int) &*.)
--[red_deref]-->
Time 15: in function main, expression
  <loc p> = (int *) (<ptr x> + (unsigned int) &. - (unsigned int) &*.)
--[red_addrof]-->
Time 16: in function main, expression
  <loc p> = (int *) (<ptr x> + (unsigned int) <ptr y+4> - (unsigned int) &*.)
--[red_cast]-->
Time 17: in function main, expression
  <loc p> = (int *) (<ptr x> + <ptr y+4> - (unsigned int) &*.)
Stuck state: in function main, expression
  <loc p> = (int *) (<ptr x> + <ptr y+4> - (unsigned int) &*(y + 0))
Stuck subexpression: <ptr x> + <ptr y+4>
ERROR: Undefined behavior
In file included from pointer_arith_algebraic_properties_3_auto.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.

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] Killed {msg: MerrAccess Store [pointer_arith_algebraic_properties_3_auto.c:8:3-10] OutOfBoundPtr} END EXEC[0] Time spent: 0.015064 seconds
cerberus-symbolic
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		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
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		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
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 139 A pointer (or array subscript) outside the bounds of an object: > in main at pointer_arith_algebraic_properties_3_auto.c:5:3 Undefined behavior (UB-CEA1): see C11 section 6.5.6:8 http://rvdoc.org/C11/6.5.6 see C11 section J.2:1 item 46 http://rvdoc.org/C11/J.2 see CERT-C section ARR30-C http://rvdoc.org/CERT-C/ARR30-C see CERT-C section ARR37-C http://rvdoc.org/CERT-C/ARR37-C see CERT-C section STR31-C http://rvdoc.org/CERT-C/STR31-C see MISRA-C section 8.18:1 http://rvdoc.org/MISRA-C/8.18 see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1 Computing pointer difference between two different objects: > in main at pointer_arith_algebraic_properties_3_auto.c:5:3 Undefined behavior (UB-CEA5): see C11 section 6.5.6:9 http://rvdoc.org/C11/6.5.6 see C11 section J.2:1 item 48 http://rvdoc.org/C11/J.2 see CERT-C section ARR36-C http://rvdoc.org/CERT-C/ARR36-C see MISRA-C section 8.18:2 http://rvdoc.org/MISRA-C/8.18 see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1 Conversion from an integer to non-null pointer: > in main at pointer_arith_algebraic_properties_3_auto.c:5:3 Implementation defined behavior (IMPL-CCV13): see C11 section 6.3.2.3:5 http://rvdoc.org/C11/6.3.2.3 see CERT section INT36-C http://rvdoc.org/CERT/INT36-C Indeterminate value used in an expression: > in main at pointer_arith_algebraic_properties_3_auto.c:5:3 Undefined behavior (UB-CEE2): see C11 section 6.2.4 http://rvdoc.org/C11/6.2.4 see C11 section 6.7.9 http://rvdoc.org/C11/6.7.9 see C11 section 6.8 http://rvdoc.org/C11/6.8 see C11 section J.2:1 item 11 http://rvdoc.org/C11/J.2 see CERT-C section EXP33-C http://rvdoc.org/CERT-C/EXP33-C see MISRA-C section 8.9:1 http://rvdoc.org/MISRA-C/8.9 see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1 Dereferencing a null pointer: > in main at pointer_arith_algebraic_properties_3_auto.c:8:3 Undefined behavior (UB-CER3): see C11 section 6.5.3.2:4 http://rvdoc.org/C11/6.5.3.2 see C11 section J.2:1 item 43 http://rvdoc.org/C11/J.2 see CERT-C section EXP34-C http://rvdoc.org/CERT-C/EXP34-C see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1 Execution failed (configuration dumped)
ch2o		pointer_arith_algebraic_properties_3_auto.c:2:10: fatal error: inttypes.h: No such file or directory #include <inttypes.h> ^~~~~~~~~~~~ compilation terminated.
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 = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.); p = 11; printf(__stringlit_1, (. + 1), p); return 0; return 0; --[step_seq]--> Time 2: in function main, statement p = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.); p = 11; printf(__stringlit_1, (. + 1), p); return 0; --[step_seq]--> Time 3: in function main, statement p = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.); --[step_do_1]--> Time 4: in function main, expression p = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.) --[red_var_local]--> Time 5: in function main, expression <loc p> = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.) --[red_var_local]--> Time 6: in function main, expression <loc p> = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.) --[red_rvalof]--> Time 7: in function main, expression <loc p> = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.) --[red_binop]--> Time 8: in function main, expression <loc p> = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.) --[red_deref]--> Time 9: in function main, expression <loc p> = (int ) ((unsigned int) &. + (unsigned int) &. - (unsigned int) &.) --[red_addrof]--> Time 10: in function main, expression <loc p> = (int ) ((unsigned int) <ptr x> + (unsigned int) &. - (unsigned int) &.) --[red_cast]--> Time 11: in function main, expression <loc p> = (int ) (<ptr x> + (unsigned int) &. - (unsigned int) &.) --[red_var_local]--> Time 12: in function main, expression <loc p> = (int ) (<ptr x> + (unsigned int) &. - (unsigned int) &.) --[red_rvalof]--> Time 13: in function main, expression <loc p> = (int ) (<ptr x> + (unsigned int) &. - (unsigned int) &.) --[red_binop]--> Time 14: in function main, expression <loc p> = (int ) (<ptr x> + (unsigned int) &. - (unsigned int) &.) --[red_deref]--> Time 15: in function main, expression <loc p> = (int ) (<ptr x> + (unsigned int) &. - (unsigned int) &.) --[red_addrof]--> Time 16: in function main, expression <loc p> = (int ) (<ptr x> + (unsigned int) <ptr y+4> - (unsigned int) &.) --[red_cast]--> Time 17: in function main, expression <loc p> = (int ) (<ptr x> + <ptr y+4> - (unsigned int) &.) Stuck state: in function main, expression <loc p> = (int ) (<ptr x> + <ptr y+4> - (unsigned int) &(y + 0)) Stuck subexpression: <ptr x> + <ptr y+4> ERROR: Undefined behavior In file included from pointer_arith_algebraic_properties_3_auto.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.

Example: pointer_arith_algebraic_properties_3_auto.c

Example: `pointer_arith_algebraic_properties_3_auto.c`