gdb/testsuite/gdb.base/watchpoint.c

   1 #include <stdio.h>
   2 /*
   3  *      Since using watchpoints can be very slow, we have to take some pains to
   4  *      ensure that we don't run too long with them enabled or we run the risk
   5  *      of having the test timeout.  To help avoid this, we insert some marker
   6  *      functions in the execution stream so we can set breakpoints at known
   7  *      locations, without worrying about invalidating line numbers by changing
   8  *      this file.  We use null bodied functions are markers since gdb does
   9  *      not support breakpoints at labeled text points at this time.
  10  *
  11  *      One place we need is a marker for when we start executing our tests
  12  *      instructions rather than any process startup code, so we insert one
  13  *      right after entering main().  Another is right before we finish, before
  14  *      we start executing any process termination code.
  15  *
  16  *      Another problem we have to guard against, at least for the test
  17  *      suite, is that we need to ensure that the line that causes the
  18  *      watchpoint to be hit is still the current line when gdb notices
  19  *      the hit.  Depending upon the specific code generated by the compiler,
  20  *      the instruction after the one that triggers the hit may be part of
  21  *      the same line or part of the next line.  Thus we ensure that there
  22  *      are always some instructions to execute on the same line after the
  23  *      code that should trigger the hit.
  24  */
  25
  26 int count = -1;
  27 int ival1 = -1;
  28 int ival2 = -1;
  29 int ival3 = -1;
  30 int ival4 = -1;
  31 char buf[10];
  32 struct foo
  33 {
  34   int val;
  35 };
  36 struct foo struct1, struct2, *ptr1, *ptr2;
  37
  38 int doread = 0;
  39
  40 void marker1 ()
  41 {
  42 }
  43
  44 void marker2 ()
  45 {
  46 }
  47
  48 void marker4 ()
  49 {
  50 }
  51
  52 void marker5 ()
  53 {
  54 }
  55
  56 void
  57 func2 ()
  58 {
  59 }
  60
  61 int
  62 func1 ()
  63 {
  64   /* The point of this is that we will set a breakpoint at this call.
  65
  66      Then, if DECR_PC_AFTER_BREAK equals the size of a function call
  67      instruction (true on a sun3 if this is gcc-compiled--FIXME we
  68      should use asm() to make it work for any compiler, present or
  69      future), then we will end up branching to the location just after
  70      the breakpoint.  And we better not confuse that with hitting the
  71      breakpoint.  */
  72   func2 ();
  73   return 73;
  74 }
  75
  76 int main ()
  77 {
  78 #ifdef usestubs
  79   set_debug_traps();
  80   breakpoint();
  81 #endif
  82   struct1.val = 1;
  83   struct2.val = 2;
  84   ptr1 = &struct1;
  85   ptr2 = &struct2;
  86   marker1 ();
  87   func1 ();
  88   for (count = 0; count < 4; count++) {
  89     ival1 = count;
  90     ival3 = count; ival4 = count;
  91   }
  92   ival1 = count; /* Outside loop */
  93   ival2 = count;
  94   ival3 = count; ival4 = count;
  95   marker2 ();
  96   if (doread)
  97     {
  98       static char msg[] = "type stuff for buf now:";
  99       write (1, msg, sizeof (msg) - 1);
 100       read (0, &buf[0], 5);
 101     }
 102   marker4 ();
 103
 104   /* We have a watchpoint on ptr1->val.  It should be triggered if
 105      ptr1's value changes.  */
 106   ptr1 = ptr2;
 107
 108   /* This should not trigger the watchpoint.  If it does, then we
 109      used the wrong value chain to re-insert the watchpoints or we
 110      are not evaluating the watchpoint expression correctly.  */
 111   struct1.val = 5;
 112   marker5 ();
 113
 114   /* We have a watchpoint on ptr1->val.  It should be triggered if
 115      ptr1's value changes.  */
 116   ptr1 = ptr2;
 117
 118   /* This should not trigger the watchpoint.  If it does, then we
 119      used the wrong value chain to re-insert the watchpoints or we
 120      are not evaluating the watchpoint expression correctly.  */
 121   struct1.val = 5;
 122   marker5 ();
 123   return 0;
 124 }