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[30] = "testtesttesttesttesttesttestte";
  34 struct foo
  35 {
  36   int val;
  37 };
  38 struct foo struct1, struct2, *ptr1, *ptr2;
  39
  40 int doread = 0;
  41
  42 char *global_ptr;
  43 char **global_ptr_ptr;
  44
  45 void marker1 ()
  46 {
  47 }
  48
  49 void marker2 ()
  50 {
  51 }
  52
  53 void marker4 ()
  54 {
  55 }
  56
  57 void marker5 ()
  58 {
  59 }
  60
  61 void marker6 ()
  62 {
  63 }
  64
  65 #ifdef PROTOTYPES
  66 void recurser (int  x)
  67 #else
  68 void recurser (x) int  x;
  69 #endif
  70 {
  71   int  local_x;
  72
  73   if (x > 0)
  74     recurser (x-1);
  75   local_x = x;
  76 }
  77
  78 void
  79 func2 ()
  80 {
  81   int  local_a;
  82   static int  static_b;
  83
  84   ival5++;
  85   local_a = ival5;
  86   static_b = local_a;
  87 }
  88
  89 void
  90 func3 ()
  91 {
  92   int x;
  93   int y;
  94
  95   x = 0;
  96   x = 1;                                /* second x assignment */
  97   y = 1;
  98   y = 2;
  99   buf[26] = 3;
 100 }
 101
 102 int
 103 func1 ()
 104 {
 105   /* The point of this is that we will set a breakpoint at this call.
 106
 107      Then, if DECR_PC_AFTER_BREAK equals the size of a function call
 108      instruction (true on a sun3 if this is gcc-compiled--FIXME we
 109      should use asm() to make it work for any compiler, present or
 110      future), then we will end up branching to the location just after
 111      the breakpoint.  And we better not confuse that with hitting the
 112      breakpoint.  */
 113   func2 ();
 114   return 73;
 115 }
 116
 117 void
 118 func4 ()
 119 {
 120   buf[0] = 3;
 121   global_ptr = buf;
 122   buf[0] = 7;
 123   buf[1] = 5;
 124   global_ptr_ptr = &global_ptr;
 125   buf[0] = 9;
 126   global_ptr++;
 127 }
 128
 129 void
 130 func5 ()
 131 {
 132   int val = 0, val2 = 23;
 133   int *x = &val;
 134
 135   /* func5 breakpoint here */
 136   x = &val2;
 137   val = 27;
 138 }
 139
 140 int main ()
 141 {
 142 #ifdef usestubs
 143   set_debug_traps();
 144   breakpoint();
 145 #endif
 146   struct1.val = 1;
 147   struct2.val = 2;
 148   ptr1 = &struct1;
 149   ptr2 = &struct2;
 150   marker1 ();
 151   func1 ();
 152   for (count = 0; count < 4; count++) {
 153     ival1 = count;
 154     ival3 = count; ival4 = count;
 155   }
 156   ival1 = count; /* Outside loop */
 157   ival2 = count;
 158   ival3 = count; ival4 = count;
 159   marker2 ();
 160   if (doread)
 161     {
 162       static char msg[] = "type stuff for buf now:";
 163       write (1, msg, sizeof (msg) - 1);
 164       read (0, &buf[0], 5);
 165     }
 166   marker4 ();
 167
 168   /* We have a watchpoint on ptr1->val.  It should be triggered if
 169      ptr1's value changes.  */
 170   ptr1 = ptr2;
 171
 172   /* This should not trigger the watchpoint.  If it does, then we
 173      used the wrong value chain to re-insert the watchpoints or we
 174      are not evaluating the watchpoint expression correctly.  */
 175   struct1.val = 5;
 176   marker5 ();
 177
 178   /* We have a watchpoint on ptr1->val.  It should be triggered if
 179      ptr1's value changes.  */
 180   ptr1 = ptr2;
 181
 182   /* This should not trigger the watchpoint.  If it does, then we
 183      used the wrong value chain to re-insert the watchpoints or we
 184      are not evaluating the watchpoint expression correctly.  */
 185   struct1.val = 5;
 186   marker5 ();
 187
 188   /* We're going to watch locals of func2, to see that out-of-scope
 189      watchpoints are detected and properly deleted.
 190      */
 191   marker6 ();
 192
 193   /* This invocation is used for watches of a single
 194      local variable. */
 195   func2 ();
 196
 197   /* This invocation is used for watches of an expression
 198      involving a local variable. */
 199   func2 ();
 200
 201   /* This invocation is used for watches of a static
 202      (non-stack-based) local variable. */
 203   func2 ();
 204
 205   /* This invocation is used for watches of a local variable
 206      when recursion happens.
 207      */
 208   marker6 ();
 209   recurser (2);
 210
 211   marker6 ();
 212
 213   func3 ();
 214
 215   func4 ();
 216
 217   func5 ();
 218
 219   return 0;
 220 }