1 2 #include <stdio.h> 3 #include <assert.h> 4 #include <dlfcn.h> 5 6 /* see comments in preen_invar_so.c for explanation of this */ 7 8 9 int main ( void ) 10 { 11 int i, r, sum = 0; 12 char* im_a_global_array; 13 void* hdl = dlopen("./preen_invars_so.so", RTLD_NOW); 14 assert(hdl); 15 im_a_global_array = dlsym(hdl, "im_a_global_array"); 16 assert(im_a_global_array); 17 /* printf("%p %p\n", im_a_global_array, me_too_me_too); */ 18 19 /* poke around in the global array, so as to cause exp-ptrcheck 20 to generate an Inv_Global invar for it. */ 21 for (i = 10/*ERROR*/; i >= 0; i--) { 22 sum += im_a_global_array[i]; 23 } 24 /* iterating 10 .. 0 causes an Unknown->Global transition at i = 9. 25 We do it this way in order that at the end of a loop, there is a 26 Global invar in place for the memory read in the loop, so that 27 the subsequent dlclose (hence munmap) causes it to get preened. 28 29 Unfortunately there's nothing to show that the preen was 30 successful or happened at all. The only way to see is from the 31 -v output: 32 33 --686-- sg_: 251 Invars preened, of which 1 changed 34 35 It's the "1 changed" bit which is significant. 36 */ 37 38 /* let's hope gcc is not clever enough to optimise this away, since 39 if it does, then it will also nuke the preceding loop, and 40 thereby render this test program useless. */ 41 42 if (sum & 1) printf("%s bar %d\n", "foo", sum & 1); else 43 printf("foo %s %d\n", "bar", 1 - (sum & 1)); 44 45 /* Now close (== unmap) the array, so that exp-ptrcheck has to check 46 its collection of Inv_Global invars, and remove this one from 47 it. */ 48 r = dlclose(hdl); 49 assert(r == 0); 50 51 return 0; 52 } 53
