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 struct foo2
  46 {
  47   int val[2];
  48 };
  49 struct foo2 foo2;
  50
  51 struct foo4
  52 {
  53   int val[4];
  54 };
  55 struct foo4 foo4;
  56
  57 struct foo5
  58 {
  59   struct { int x; } *p;
  60 };
  61
  62 struct foo5 *nullptr;
  63
  64 void marker1 ()
  65 {
  66 }
  67
  68 void marker2 ()
  69 {
  70 }
  71
  72 void marker4 ()
  73 {
  74 }
  75
  76 void marker5 ()
  77 {
  78 }
  79
  80 void marker6 ()
  81 {
  82 }
  83
  84 void recurser (int  x)
  85 {
  86   int  local_x = 0;
  87
  88   if (x > 0)
  89     recurser (x-1);
  90   local_x = x;
  91 }
  92
  93 void
  94 func2 ()
  95 {
  96   int  local_a = 0;
  97   static int  static_b;
  98
  99   /* func2 breakpoint here */
 100   ival5++;
 101   local_a = ival5;
 102   static_b = local_a;
 103 }
 104
 105 void
 106 func3 ()
 107 {
 108   int x;
 109   int y;
 110
 111   x = 0;
 112   x = 1;                                /* second x assignment */
 113   y = 1;
 114   y = 2;
 115   buf[26] = 3;
 116 }
 117
 118 int
 119 func1 ()
 120 {
 121   /* The point of this is that we will set a breakpoint at this call.
 122
 123      Then, if DECR_PC_AFTER_BREAK equals the size of a function call
 124      instruction (true on a sun3 if this is gcc-compiled--FIXME we
 125      should use asm() to make it work for any compiler, present or
 126      future), then we will end up branching to the location just after
 127      the breakpoint.  And we better not confuse that with hitting the
 128      breakpoint.  */
 129   func2 ();
 130   return 73;
 131 }
 132
 133 void
 134 func4 ()
 135 {
 136   buf[0] = 3;
 137   global_ptr = buf;
 138   buf[0] = 7;
 139   buf[1] = 5;
 140   global_ptr_ptr = &global_ptr;
 141   buf[0] = 9;
 142   global_ptr++;
 143 }
 144
 145 void
 146 func5 ()
 147 {
 148   int val = 0, val2 = 23;
 149   int *x = &val;
 150
 151   /* func5 breakpoint here */
 152   x = &val2;
 153   val = 27;
 154 }
 155
 156 void
 157 func6 (void)
 158 {
 159   /* func6 breakpoint here */
 160   foo2.val[1] = 0;
 161   foo2.val[1] = 11;
 162 }
 163
 164 void
 165 func7 (void)
 166 {
 167   /* func7 breakpoint here */
 168   foo4.val[3] = 0;
 169   foo4.val[3] = 33;
 170 }
 171
 172 int main ()
 173 {
 174   struct1.val = 1;
 175   struct2.val = 2;
 176   ptr1 = &struct1;
 177   ptr2 = &struct2;
 178   marker1 ();
 179   func1 ();
 180   for (count = 0; count < 4; count++) {
 181     ival1 = count;
 182     ival3 = count; ival4 = count;
 183   }
 184   ival1 = count; /* Outside loop */
 185   ival2 = count;
 186   ival3 = count; ival4 = count;
 187   marker2 ();
 188   if (doread)
 189     {
 190       static char msg[] = "type stuff for buf now:";
 191       write (1, msg, sizeof (msg) - 1);
 192       read (0, &buf[0], 5);
 193     }
 194   marker4 ();
 195
 196   /* We have a watchpoint on ptr1->val.  It should be triggered if
 197      ptr1's value changes.  */
 198   ptr1 = ptr2;
 199
 200   /* This should not trigger the watchpoint.  If it does, then we
 201      used the wrong value chain to re-insert the watchpoints or we
 202      are not evaluating the watchpoint expression correctly.  */
 203   struct1.val = 5;
 204   marker5 ();
 205
 206   /* We have a watchpoint on ptr1->val.  It should be triggered if
 207      ptr1's value changes.  */
 208   ptr1 = ptr2;
 209
 210   /* This should not trigger the watchpoint.  If it does, then we
 211      used the wrong value chain to re-insert the watchpoints or we
 212      are not evaluating the watchpoint expression correctly.  */
 213   struct1.val = 5;
 214   marker5 ();
 215
 216   /* We're going to watch locals of func2, to see that out-of-scope
 217      watchpoints are detected and properly deleted.
 218      */
 219   marker6 ();
 220
 221   /* This invocation is used for watches of a single
 222      local variable. */
 223   func2 ();
 224
 225   /* This invocation is used for watches of an expression
 226      involving a local variable. */
 227   func2 ();
 228
 229   /* This invocation is used for watches of a static
 230      (non-stack-based) local variable. */
 231   func2 ();
 232
 233   /* This invocation is used for watches of a local variable
 234      when recursion happens.
 235      */
 236   marker6 ();
 237   recurser (2);
 238
 239   /* This invocation is used for watches of a local variable with explicitly
 240      specified scope when recursion happens.
 241      */
 242   marker6 ();
 243   recurser (2);
 244
 245   marker6 ();
 246
 247   func3 ();
 248
 249   func4 ();
 250
 251   func5 ();
 252
 253   func6 ();
 254
 255   func7 ();
 256
 257   return 0;
 258 }