aboutsummaryrefslogtreecommitdiff
path: root/gdb/common/common-exceptions.c
blob: b2d8e25793286e80f95bc45831f256c6934bde54 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
/* Exception (throw catch) mechanism, for GDB, the GNU debugger.

   Copyright (C) 1986-2019 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "common-defs.h"
#include "common-exceptions.h"
#include <forward_list>

const struct gdb_exception exception_none;

/* Possible catcher states.  */
enum catcher_state {
  /* Initial state, a new catcher has just been created.  */
  CATCHER_CREATED,
  /* The catch code is running.  */
  CATCHER_RUNNING,
  CATCHER_RUNNING_1,
  /* The catch code threw an exception.  */
  CATCHER_ABORTING
};

/* Possible catcher actions.  */
enum catcher_action {
  CATCH_ITER,
  CATCH_ITER_1,
  CATCH_THROWING
};

struct catcher
{
  enum catcher_state state = CATCHER_CREATED;
  /* Jump buffer pointing back at the exception handler.  */
  jmp_buf buf;
  /* Status buffer belonging to the exception handler.  */
  struct gdb_exception exception = exception_none;
};

/* Where to go for throw_exception().  */
static std::forward_list<struct catcher> catchers;

jmp_buf *
exceptions_state_mc_init ()
{
  catchers.emplace_front ();
  return &catchers.front ().buf;
}

/* Catcher state machine.  Returns non-zero if the m/c should be run
   again, zero if it should abort.  */

static int
exceptions_state_mc (enum catcher_action action)
{
  switch (catchers.front ().state)
    {
    case CATCHER_CREATED:
      switch (action)
	{
	case CATCH_ITER:
	  /* Allow the code to run the catcher.  */
	  catchers.front ().state = CATCHER_RUNNING;
	  return 1;
	default:
	  internal_error (__FILE__, __LINE__, _("bad state"));
	}
    case CATCHER_RUNNING:
      switch (action)
	{
	case CATCH_ITER:
	  /* No error/quit has occured.  */
	  return 0;
	case CATCH_ITER_1:
	  catchers.front ().state = CATCHER_RUNNING_1;
	  return 1;
	case CATCH_THROWING:
	  catchers.front ().state = CATCHER_ABORTING;
	  /* See also throw_exception.  */
	  return 1;
	default:
	  internal_error (__FILE__, __LINE__, _("bad switch"));
	}
    case CATCHER_RUNNING_1:
      switch (action)
	{
	case CATCH_ITER:
	  /* The did a "break" from the inner while loop.  */
	  return 0;
	case CATCH_ITER_1:
	  catchers.front ().state = CATCHER_RUNNING;
	  return 0;
	case CATCH_THROWING:
	  catchers.front ().state = CATCHER_ABORTING;
	  /* See also throw_exception.  */
	  return 1;
	default:
	  internal_error (__FILE__, __LINE__, _("bad switch"));
	}
    case CATCHER_ABORTING:
      switch (action)
	{
	case CATCH_ITER:
	  {
	    /* Exit normally if this catcher can handle this
	       exception.  The caller analyses the func return
	       values.  */
	    return 0;
	  }
	default:
	  internal_error (__FILE__, __LINE__, _("bad state"));
	}
    default:
      internal_error (__FILE__, __LINE__, _("bad switch"));
    }
}

int
exceptions_state_mc_catch (struct gdb_exception *exception,
			   int mask)
{
  *exception = std::move (catchers.front ().exception);
  catchers.pop_front ();

  if (exception->reason < 0)
    {
      if (mask & RETURN_MASK (exception->reason))
	{
	  /* Exit normally and let the caller handle the
	     exception.  */
	  return 1;
	}

      /* The caller didn't request that the event be caught, relay the
	 event to the next exception_catch/CATCH_SJLJ.  */
      throw_exception_sjlj (*exception);
    }

  /* No exception was thrown.  */
  return 0;
}

int
exceptions_state_mc_action_iter (void)
{
  return exceptions_state_mc (CATCH_ITER);
}

int
exceptions_state_mc_action_iter_1 (void)
{
  return exceptions_state_mc (CATCH_ITER_1);
}

/* Called by the default catch block.  IOW, we'll get here before
   jumping out to the next outermost scope an exception if a GDB
   exception is not caught.  */

void
exception_rethrow (void)
{
  throw;
}

/* Return EXCEPTION to the nearest containing CATCH_SJLJ block.  */

void
throw_exception_sjlj (struct gdb_exception exception)
{
  /* Jump to the nearest CATCH_SJLJ block, communicating REASON to
     that call via setjmp's return value.  Note that REASON can't be
     zero, by definition in common-exceptions.h.  */
  exceptions_state_mc (CATCH_THROWING);
  catchers.front ().exception = exception;
  longjmp (catchers.front ().buf, exception.reason);
}

/* Implementation of throw_exception that uses C++ try/catch.  */

static ATTRIBUTE_NORETURN void
throw_exception_cxx (struct gdb_exception exception)
{
  if (exception.reason == RETURN_QUIT)
    {
      gdb_exception_RETURN_MASK_QUIT ex (exception);
      throw ex;
    }
  else if (exception.reason == RETURN_ERROR)
    {
      gdb_exception_RETURN_MASK_ERROR ex (exception);
      throw ex;
    }
  else
    gdb_assert_not_reached ("invalid return reason");
}

void
throw_exception (struct gdb_exception exception)
{
  throw_exception_cxx (exception);
}

static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0)
throw_it (enum return_reason reason, enum errors error, const char *fmt,
	  va_list ap)
{
  struct gdb_exception e;

  /* Create the exception.  */
  e.reason = reason;
  e.error = error;
  e.message.reset (new std::string (string_vprintf (fmt, ap)));

  /* Throw the exception.  */
  throw_exception (e);
}

void
throw_verror (enum errors error, const char *fmt, va_list ap)
{
  throw_it (RETURN_ERROR, error, fmt, ap);
}

void
throw_vquit (const char *fmt, va_list ap)
{
  throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap);
}

void
throw_error (enum errors error, const char *fmt, ...)
{
  va_list args;

  va_start (args, fmt);
  throw_verror (error, fmt, args);
  va_end (args);
}

void
throw_quit (const char *fmt, ...)
{
  va_list args;

  va_start (args, fmt);
  throw_vquit (fmt, args);
  va_end (args);
}