gdb/testsuite/gdb.reverse/watch-reverse.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2008-2019 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <stdio.h>
  19 #include <unistd.h>
  20 /*
  21  *      Since using watchpoints can be very slow, we have to take some pains to
  22  *      ensure that we don't run too long with them enabled or we run the risk
  23  *      of having the test timeout.  To help avoid this, we insert some marker
  24  *      functions in the execution stream so we can set breakpoints at known
  25  *      locations, without worrying about invalidating line numbers by changing
  26  *      this file.  We use null bodied functions are markers since gdb does
  27  *      not support breakpoints at labeled text points at this time.
  28  *
  29  *      One place we need is a marker for when we start executing our tests
  30  *      instructions rather than any process startup code, so we insert one
  31  *      right after entering main().  Another is right before we finish, before
  32  *      we start executing any process termination code.
  33  *
  34  *      Another problem we have to guard against, at least for the test
  35  *      suite, is that we need to ensure that the line that causes the
  36  *      watchpoint to be hit is still the current line when gdb notices
  37  *      the hit.  Depending upon the specific code generated by the compiler,
  38  *      the instruction after the one that triggers the hit may be part of
  39  *      the same line or part of the next line.  Thus we ensure that there
  40  *      are always some instructions to execute on the same line after the
  41  *      code that should trigger the hit.
  42  */
  43
  44 int count = -1;
  45 int ival1 = -1;
  46 int ival2 = -1;
  47 int ival3 = -1;
  48 int ival4 = -1;
  49 int ival5 = -1;
  50 char buf[10];
  51 struct foo
  52 {
  53   int val;
  54 };
  55 struct foo struct1, struct2, *ptr1, *ptr2;
  56
  57 int doread = 0;
  58
  59 char *global_ptr;
  60
  61 void marker1 ()
  62 {
  63 }
  64
  65 void marker2 ()
  66 {
  67 }
  68
  69 void marker4 ()
  70 {
  71 }
  72
  73 void marker5 ()
  74 {
  75 }
  76
  77 void marker6 ()
  78 {
  79 }
  80
  81 void recurser (int  x)
  82 {
  83   int  local_x;
  84
  85   if (x > 0)
  86     recurser (x-1);
  87   local_x = x;
  88 }
  89
  90 void
  91 func2 ()
  92 {
  93   int  local_a;
  94   static int  static_b;
  95
  96   ival5++;
  97   local_a = ival5;
  98   static_b = local_a;
  99 }
 100
 101 void
 102 func3 ()
 103 {
 104   int x;
 105   int y;
 106
 107   x = 0;
 108   x = 1;                                /* second x assignment */
 109   y = 1;
 110   y = 2;
 111 }
 112
 113 int
 114 func1 ()
 115 {
 116   /* The point of this is that we will set a breakpoint at this call.
 117
 118      Then, if DECR_PC_AFTER_BREAK equals the size of a function call
 119      instruction (true on a sun3 if this is gcc-compiled--FIXME we
 120      should use asm() to make it work for any compiler, present or
 121      future), then we will end up branching to the location just after
 122      the breakpoint.  And we better not confuse that with hitting the
 123      breakpoint.  */
 124   func2 ();
 125   return 73;
 126 }
 127
 128 void
 129 func4 ()
 130 {
 131   buf[0] = 3;
 132   global_ptr = buf;
 133   buf[0] = 7;
 134 }
 135
 136 int main ()
 137 {
 138   struct1.val = 1;
 139   struct2.val = 2;
 140   ptr1 = &struct1;
 141   ptr2 = &struct2;
 142   marker1 ();
 143   func1 ();
 144   for (count = 0; count < 4; count++) {
 145     ival1 = count;
 146     ival3 = count; ival4 = count;
 147   }
 148   ival1 = count; /* Outside loop */
 149   ival2 = count;
 150   ival3 = count; ival4 = count;
 151   marker2 ();
 152   if (doread)
 153     {
 154       static char msg[] = "type stuff for buf now:";
 155       write (1, msg, sizeof (msg) - 1);
 156       read (0, &buf[0], 5);
 157     }
 158   marker4 ();
 159
 160   /* We have a watchpoint on ptr1->val.  It should be triggered if
 161      ptr1's value changes.  */
 162   ptr1 = ptr2;
 163
 164   /* This should not trigger the watchpoint.  If it does, then we
 165      used the wrong value chain to re-insert the watchpoints or we
 166      are not evaluating the watchpoint expression correctly.  */
 167   struct1.val = 5;
 168   marker5 ();
 169
 170   /* We have a watchpoint on ptr1->val.  It should be triggered if
 171      ptr1's value changes.  */
 172   ptr1 = ptr2;
 173
 174   /* This should not trigger the watchpoint.  If it does, then we
 175      used the wrong value chain to re-insert the watchpoints or we
 176      are not evaluating the watchpoint expression correctly.  */
 177   struct1.val = 5;
 178   marker5 ();
 179
 180   /* We're going to watch locals of func2, to see that out-of-scope
 181      watchpoints are detected and properly deleted.
 182      */
 183   marker6 ();
 184
 185   /* This invocation is used for watches of a single
 186      local variable. */
 187   func2 ();
 188
 189   /* This invocation is used for watches of an expression
 190      involving a local variable. */
 191   func2 ();
 192
 193   /* This invocation is used for watches of a static
 194      (non-stack-based) local variable. */
 195   func2 ();
 196
 197   /* This invocation is used for watches of a local variable
 198      when recursion happens.
 199      */
 200   marker6 ();
 201   recurser (2);
 202
 203   marker6 ();
 204
 205   func3 ();
 206
 207   func4 ();
 208
 209   return 0;
 210 } /* end of main */
 211