Example: provenance_basic_using_uintptr_t_global_xy.c

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    #include <stdio.h>
    #include <string.h> 
    #include <stdint.h>
    #include <inttypes.h>
    int x=1, y=2;
    int main() {
      uintptr_t ux = (uintptr_t)&x;
      uintptr_t uy = (uintptr_t)&y;
      uintptr_t offset = 4;
      ux = ux + offset;
      int *p = (int *)ux; // does this have UB?
      int *q = &y;
      printf("Addresses: &x=%p p=%p &y=%"PRIxPTR\
             "\n",(void*)&x,(void*)p,(unsigned long)uy);
      if (memcmp(&p, &q, sizeof(p)) == 0) {
        *p = 11; // does this have undefined behaviour?
        printf("x=%d  y=%d  *p=%d  *q=%d\n",x,y,*p,*q); 
      }
    }
[link to run test in Cerberus]

Experimental data (what does this mean?) 



cerberus-concrete-PVI-plain Addresses: &x=(@0, 0xfffffff8) p=(@empty, 0xfffffffc) &y=fffffff4


cerberus-concrete-PVI-ae Addresses: &x=(@0, 0xfffffff8) p=(@empty, 0xfffffffc) &y=fffffff4


cerberus-concrete-PVI-ae-udi Addresses: &x=(@0, 0xfffffff8) p=(@0, 0xfffffffc) &y=fffffff4


gcc-8.3-O0 Addresses: &x=0x100001020 p=0x100001024 &y=100001024
x=1  y=11  *p=11  *q=11


gcc-8.3-O2 Addresses: &x=0x10000101c p=0x100001020 &y=100001018


gcc-8.3-O3 Addresses: &x=0x10000101c p=0x100001020 &y=100001018


gcc-8.3-O2-no-strict-aliasing Addresses: &x=0x10000101c p=0x100001020 &y=100001018


gcc-8.3-O3-no-strict-aliasing Addresses: &x=0x10000101c p=0x100001020 &y=100001018


clang-7.0.1-O0 Addresses: &x=0x100001018 p=0x10000101c &y=10000101c
x=1  y=11  *p=11  *q=11


clang-7.0.1-O2 Addresses: &x=0x100001018 p=0x10000101c &y=10000101c
x=1  y=11  *p=11  *q=11


clang-7.0.1-O3 Addresses: &x=0x100001018 p=0x10000101c &y=10000101c
x=1  y=11  *p=11  *q=11


clang-7.0.1-O2-no-strict-aliasing Addresses: &x=0x100001018 p=0x10000101c &y=10000101c
x=1  y=11  *p=11  *q=11


clang-7.0.1-O3-no-strict-aliasing Addresses: &x=0x100001018 p=0x10000101c &y=10000101c
x=1  y=11  *p=11  *q=11


icc-19-O0 Addresses: &x=0x600b88 p=0x600b8c &y=600b8c
x=1  y=11  *p=11  *q=11


icc-19-O2 Addresses: &x=0x6046c0 p=0x6046c4 &y=6046c4
x=1  y=2  *p=11  *q=11


icc-19-O3 Addresses: &x=0x6046c0 p=0x6046c4 &y=6046c4
x=1  y=2  *p=11  *q=11


icc-19-O2-no-strict-aliasing Addresses: &x=0x6046c0 p=0x6046c4 &y=6046c4
x=1  y=2  *p=11  *q=11


icc-19-O3-no-strict-aliasing Addresses: &x=0x6046c0 p=0x6046c4 &y=6046c4
x=1  y=2  *p=11  *q=11