gdb/testsuite/gdb.base/watchpoint.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 /*
   4  *      Since using watchpoints can be very slow, we have to take some pains to
   5  *      ensure that we don't run too long with them enabled or we run the risk
   6  *      of having the test timeout.  To help avoid this, we insert some marker
   7  *      functions in the execution stream so we can set breakpoints at known
   8  *      locations, without worrying about invalidating line numbers by changing
   9  *      this file.  We use null bodied functions are markers since gdb does
  10  *      not support breakpoints at labeled text points at this time.
  11  *
  12  *      One place we need is a marker for when we start executing our tests
  13  *      instructions rather than any process startup code, so we insert one
  14  *      right after entering main().  Another is right before we finish, before
  15  *      we start executing any process termination code.
  16  *
  17  *      Another problem we have to guard against, at least for the test
  18  *      suite, is that we need to ensure that the line that causes the
  19  *      watchpoint to be hit is still the current line when gdb notices
  20  *      the hit.  Depending upon the specific code generated by the compiler,
  21  *      the instruction after the one that triggers the hit may be part of
  22  *      the same line or part of the next line.  Thus we ensure that there
  23  *      are always some instructions to execute on the same line after the
  24  *      code that should trigger the hit.
  25  */
  26
  27 int count = -1;
  28 int ival1 = -1;
  29 int ival2 = -1;
  30 int ival3 = -1;
  31 int ival4 = -1;
  32 int ival5 = -1;
  33 char buf[10];
  34 struct foo
  35 {
  36   int val;
  37 };
  38 struct foo struct1, struct2, *ptr1, *ptr2;
  39
  40 int doread = 0;
  41
  42 void marker1 ()
  43 {
  44 }
  45
  46 void marker2 ()
  47 {
  48 }
  49
  50 void marker4 ()
  51 {
  52 }
  53
  54 void marker5 ()
  55 {
  56 }
  57
  58 void marker6 ()
  59 {
  60 }
  61
  62 #ifdef PROTOTYPES
  63 void recurser (int  x)
  64 #else
  65 void recurser (x) int  x;
  66 #endif
  67 {
  68   int  local_x;
  69
  70   if (x > 0)
  71     recurser (x-1);
  72   local_x = x;
  73 }
  74
  75 void
  76 func2 ()
  77 {
  78   int  local_a;
  79   static int  static_b;
  80
  81   ival5++;
  82   local_a = ival5;
  83   static_b = local_a;
  84 }
  85
  86 void
  87 func3 ()
  88 {
  89   int x;
  90   int y;
  91
  92   x = 0;
  93   x = 1;                                /* second x assignment */
  94   y = 1;
  95   y = 2;
  96 }
  97
  98 int
  99 func1 ()
 100 {
 101   /* The point of this is that we will set a breakpoint at this call.
 102
 103      Then, if DECR_PC_AFTER_BREAK equals the size of a function call
 104      instruction (true on a sun3 if this is gcc-compiled--FIXME we
 105      should use asm() to make it work for any compiler, present or
 106      future), then we will end up branching to the location just after
 107      the breakpoint.  And we better not confuse that with hitting the
 108      breakpoint.  */
 109   func2 ();
 110   return 73;
 111 }
 112
 113 int main ()
 114 {
 115 #ifdef usestubs
 116   set_debug_traps();
 117   breakpoint();
 118 #endif
 119   struct1.val = 1;
 120   struct2.val = 2;
 121   ptr1 = &struct1;
 122   ptr2 = &struct2;
 123   marker1 ();
 124   func1 ();
 125   for (count = 0; count < 4; count++) {
 126     ival1 = count;
 127     ival3 = count; ival4 = count;
 128   }
 129   ival1 = count; /* Outside loop */
 130   ival2 = count;
 131   ival3 = count; ival4 = count;
 132   marker2 ();
 133   if (doread)
 134     {
 135       static char msg[] = "type stuff for buf now:";
 136       write (1, msg, sizeof (msg) - 1);
 137       read (0, &buf[0], 5);
 138     }
 139   marker4 ();
 140
 141   /* We have a watchpoint on ptr1->val.  It should be triggered if
 142      ptr1's value changes.  */
 143   ptr1 = ptr2;
 144
 145   /* This should not trigger the watchpoint.  If it does, then we
 146      used the wrong value chain to re-insert the watchpoints or we
 147      are not evaluating the watchpoint expression correctly.  */
 148   struct1.val = 5;
 149   marker5 ();
 150
 151   /* We have a watchpoint on ptr1->val.  It should be triggered if
 152      ptr1's value changes.  */
 153   ptr1 = ptr2;
 154
 155   /* This should not trigger the watchpoint.  If it does, then we
 156      used the wrong value chain to re-insert the watchpoints or we
 157      are not evaluating the watchpoint expression correctly.  */
 158   struct1.val = 5;
 159   marker5 ();
 160
 161   /* We're going to watch locals of func2, to see that out-of-scope
 162      watchpoints are detected and properly deleted.
 163      */
 164   marker6 ();
 165
 166   /* This invocation is used for watches of a single
 167      local variable. */
 168   func2 ();
 169
 170   /* This invocation is used for watches of an expression
 171      involving a local variable. */
 172   func2 ();
 173
 174   /* This invocation is used for watches of a static
 175      (non-stack-based) local variable. */
 176   func2 ();
 177
 178   /* This invocation is used for watches of a local variable
 179      when recursion happens.
 180      */
 181   marker6 ();
 182   recurser (2);
 183
 184   marker6 ();
 185
 186   func3 ();
 187
 188   return 0;
 189 }