dhat/tests/acc.c

   1 // Testing accesses of blocks.
   2
   3 #include <stdint.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6
   7 void* m1(size_t n) { return malloc(n); }
   8
   9 void* m2(size_t n) { return malloc(n); }
  10
  11 int main(void)
  12 {
  13    // 0th char is written 0 times, 1st char is written once, etc.
  14    char* a = malloc(32);
  15    for (int i = 1; i < 32; i++) {
  16       for (int j = 0; j < i; j++) {
  17          a[i] = 0;
  18       }
  19    }
  20    free(a);
  21
  22    // Repetition and gaps.
  23    int* b = malloc(20);
  24    b[0] = 1;
  25    b[2] = b[0];
  26    for (int i = 0; i < 10; i++) {
  27       b[4] = 99;
  28    }
  29    free(b);
  30
  31    // 33 bytes, goes onto a second line in dh_view.
  32    char* c = calloc(33, 1);
  33    c[32] = 0;
  34    free(c);
  35
  36    // 1024 bytes, accesses are shown.
  37    char* d = malloc(1024);
  38    for (int i = 0; i < 1024; i++) {
  39       d[i] = d[1023 - i];
  40    }
  41    for (int i = 500; i < 600; i++) {
  42       d[i] = 0;
  43    }
  44    free(d);
  45
  46    // 1025 bytes, accesses aren't shown.
  47    char* e = calloc(1025, 1);
  48    for (int i = 0; i < 1025; i++) {
  49       e[i] += 1;
  50    }
  51    free(e);
  52
  53    // Lots of accesses, but fewer than the 0xffff max value.
  54    int* f1 = m1(100);
  55    int* f2 = m1(100);
  56    for (int i = 0; i < 50000; i++) {
  57       f1[0] = 0;
  58       f2[0] = 0;
  59    }
  60    free(f1);
  61    free(f2);
  62
  63    // Lots of accesses, more than the 0xffff max value: treated as Infinity.
  64    int* g1 = m2(100);
  65    int* g2 = m2(100);
  66    for (int i = 0; i < 100000; i++) {
  67       g1[0] = 0;
  68       g2[0] = 0;
  69    }
  70    free(g1);
  71    free(g2);
  72
  73    return 0;
  74 }