sdcc/support/regression/tests/bug-3729.c

   1 /** Code generation for f8 could overwrite the lower byte of a still-needed pointer value in register x.
   2 */
   3
   4 #include <testfwk.h>
   5
   6 #include <string.h>
   7
   8 #ifdef __SDCC_pdk14
   9 #define GUARDSIZE 4
  10 #else
  11 #define GUARDSIZE 16
  12 #endif
  13
  14 struct a { unsigned int bitfield : 1; };
  15
  16 unsigned int x;
  17
  18 void
  19 f (void)
  20 {
  21   struct a a = {0};    // Here the lower byte of a pointer to a was overwritten.
  22   x = 0xbeef;
  23   a.bitfield |= x;     // So this 1 was stored to the wrong location.
  24   if (a.bitfield != 1) // But this cheak read fom the wrong location, too, and thus got the correct value.
  25     ASSERT (0);
  26   return;
  27 }
  28
  29 void h(const char *c0, const char *c1)
  30 {
  31   ASSERT (!memcmp (c0, c1, GUARDSIZE));
  32 }
  33
  34 void
  35 f2 (void)
  36 {
  37   char c0 [GUARDSIZE] = {0};
  38   struct a a = {0};
  39   char c1 [GUARDSIZE] = {0};
  40   x = 0xbeef;
  41   a.bitfield |= x;
  42   if (a.bitfield != 1)
  43     ASSERT (0);
  44   h (c0, c1);
  45   return;
  46 }
  47
  48 void
  49 f3 (void)
  50 {
  51   char c0 [GUARDSIZE] = {0};
  52   char c1 [GUARDSIZE] = {0};
  53   f ();
  54   f2 ();
  55   h (c0, c1);
  56 }
  57
  58 void
  59 testBug(void)
  60 {
  61   f ();
  62   f2 ();
  63   f3 ();
  64 }
  65