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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.2.2/] [gcc/] [tree-iterator.c] - Blame information for rev 318

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/* Iterator routines for manipulating GENERIC and GIMPLE tree statements.
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   Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.
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   Contributed by Andrew MacLeod  <amacleod@redhat.com>
4
 
5
This file is part of GCC.
6
 
7
GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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12
GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3.  If not see
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<http://www.gnu.org/licenses/>.  */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tree.h"
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#include "tree-gimple.h"
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#include "tree-iterator.h"
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#include "ggc.h"
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29
 
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/* This is a cache of STATEMENT_LIST nodes.  We create and destroy them
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   fairly often during gimplification.  */
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static GTY ((deletable (""))) tree stmt_list_cache;
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tree
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alloc_stmt_list (void)
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{
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  tree list = stmt_list_cache;
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  if (list)
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    {
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      stmt_list_cache = TREE_CHAIN (list);
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      gcc_assert (stmt_list_cache != list);
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      memset (list, 0, sizeof(struct tree_common));
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      TREE_SET_CODE (list, STATEMENT_LIST);
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    }
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  else
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    list = make_node (STATEMENT_LIST);
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  TREE_TYPE (list) = void_type_node;
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  return list;
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}
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void
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free_stmt_list (tree t)
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{
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  gcc_assert (!STATEMENT_LIST_HEAD (t));
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  gcc_assert (!STATEMENT_LIST_TAIL (t));
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  /* If this triggers, it's a sign that the same list is being freed
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     twice.  */
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  gcc_assert (t != stmt_list_cache || stmt_list_cache == NULL);
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  TREE_CHAIN (t) = stmt_list_cache;
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  stmt_list_cache = t;
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}
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/* Links a statement, or a chain of statements, before the current stmt.  */
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void
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tsi_link_before (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode)
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{
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  struct tree_statement_list_node *head, *tail, *cur;
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  /* Die on looping.  */
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  gcc_assert (t != i->container);
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  if (TREE_CODE (t) == STATEMENT_LIST)
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    {
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      head = STATEMENT_LIST_HEAD (t);
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      tail = STATEMENT_LIST_TAIL (t);
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      STATEMENT_LIST_HEAD (t) = NULL;
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      STATEMENT_LIST_TAIL (t) = NULL;
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      free_stmt_list (t);
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      /* Empty statement lists need no work.  */
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      if (!head || !tail)
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        {
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          gcc_assert (head == tail);
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          return;
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        }
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    }
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  else
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    {
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      head = ggc_alloc (sizeof (*head));
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      head->prev = NULL;
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      head->next = NULL;
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      head->stmt = t;
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      tail = head;
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    }
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  TREE_SIDE_EFFECTS (i->container) = 1;
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  cur = i->ptr;
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  /* Link it into the list.  */
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  if (cur)
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    {
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      head->prev = cur->prev;
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      if (head->prev)
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        head->prev->next = head;
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      else
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        STATEMENT_LIST_HEAD (i->container) = head;
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      tail->next = cur;
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      cur->prev = tail;
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    }
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  else
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    {
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      head->prev = STATEMENT_LIST_TAIL (i->container);
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      if (head->prev)
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       head->prev->next = head;
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      else
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       STATEMENT_LIST_HEAD (i->container) = head;
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      STATEMENT_LIST_TAIL (i->container) = tail;
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    }
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  /* Update the iterator, if requested.  */
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  switch (mode)
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    {
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    case TSI_NEW_STMT:
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    case TSI_CONTINUE_LINKING:
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    case TSI_CHAIN_START:
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      i->ptr = head;
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      break;
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    case TSI_CHAIN_END:
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      i->ptr = tail;
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      break;
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    case TSI_SAME_STMT:
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      break;
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    }
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}
139
 
140
/* Links a statement, or a chain of statements, after the current stmt.  */
141
 
142
void
143
tsi_link_after (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode)
144
{
145
  struct tree_statement_list_node *head, *tail, *cur;
146
 
147
  /* Die on looping.  */
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  gcc_assert (t != i->container);
149
 
150
  if (TREE_CODE (t) == STATEMENT_LIST)
151
    {
152
      head = STATEMENT_LIST_HEAD (t);
153
      tail = STATEMENT_LIST_TAIL (t);
154
      STATEMENT_LIST_HEAD (t) = NULL;
155
      STATEMENT_LIST_TAIL (t) = NULL;
156
 
157
      free_stmt_list (t);
158
 
159
      /* Empty statement lists need no work.  */
160
      if (!head || !tail)
161
        {
162
          gcc_assert (head == tail);
163
          return;
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        }
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    }
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  else
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    {
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      head = ggc_alloc (sizeof (*head));
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      head->prev = NULL;
170
      head->next = NULL;
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      head->stmt = t;
172
      tail = head;
173
    }
174
 
175
  TREE_SIDE_EFFECTS (i->container) = 1;
176
 
177
  cur = i->ptr;
178
 
179
  /* Link it into the list.  */
180
  if (cur)
181
    {
182
      tail->next = cur->next;
183
      if (tail->next)
184
        tail->next->prev = tail;
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      else
186
        STATEMENT_LIST_TAIL (i->container) = tail;
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      head->prev = cur;
188
      cur->next = head;
189
    }
190
  else
191
    {
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      gcc_assert (!STATEMENT_LIST_TAIL (i->container));
193
      STATEMENT_LIST_HEAD (i->container) = head;
194
      STATEMENT_LIST_TAIL (i->container) = tail;
195
    }
196
 
197
  /* Update the iterator, if requested.  */
198
  switch (mode)
199
    {
200
    case TSI_NEW_STMT:
201
    case TSI_CHAIN_START:
202
      i->ptr = head;
203
      break;
204
    case TSI_CONTINUE_LINKING:
205
    case TSI_CHAIN_END:
206
      i->ptr = tail;
207
      break;
208
    case TSI_SAME_STMT:
209
      gcc_assert (cur);
210
      break;
211
    }
212
}
213
 
214
/* Remove a stmt from the tree list.  The iterator is updated to point to
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   the next stmt.  */
216
 
217
void
218
tsi_delink (tree_stmt_iterator *i)
219
{
220
  struct tree_statement_list_node *cur, *next, *prev;
221
 
222
  cur = i->ptr;
223
  next = cur->next;
224
  prev = cur->prev;
225
 
226
  if (prev)
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    prev->next = next;
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  else
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    STATEMENT_LIST_HEAD (i->container) = next;
230
  if (next)
231
    next->prev = prev;
232
  else
233
    STATEMENT_LIST_TAIL (i->container) = prev;
234
 
235
  if (!next && !prev)
236
    TREE_SIDE_EFFECTS (i->container) = 0;
237
 
238
  i->ptr = next;
239
}
240
 
241
/* Move all statements in the statement list after I to a new
242
   statement list.  I itself is unchanged.  */
243
 
244
tree
245
tsi_split_statement_list_after (const tree_stmt_iterator *i)
246
{
247
  struct tree_statement_list_node *cur, *next;
248
  tree old_sl, new_sl;
249
 
250
  cur = i->ptr;
251
  /* How can we possibly split after the end, or before the beginning?  */
252
  gcc_assert (cur);
253
  next = cur->next;
254
 
255
  old_sl = i->container;
256
  new_sl = alloc_stmt_list ();
257
  TREE_SIDE_EFFECTS (new_sl) = 1;
258
 
259
  STATEMENT_LIST_HEAD (new_sl) = next;
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  STATEMENT_LIST_TAIL (new_sl) = STATEMENT_LIST_TAIL (old_sl);
261
  STATEMENT_LIST_TAIL (old_sl) = cur;
262
  cur->next = NULL;
263
  next->prev = NULL;
264
 
265
  return new_sl;
266
}
267
 
268
/* Move all statements in the statement list before I to a new
269
   statement list.  I is set to the head of the new list.  */
270
 
271
tree
272
tsi_split_statement_list_before (tree_stmt_iterator *i)
273
{
274
  struct tree_statement_list_node *cur, *prev;
275
  tree old_sl, new_sl;
276
 
277
  cur = i->ptr;
278
  /* How can we possibly split after the end, or before the beginning?  */
279
  gcc_assert (cur);
280
  prev = cur->prev;
281
 
282
  old_sl = i->container;
283
  new_sl = alloc_stmt_list ();
284
  TREE_SIDE_EFFECTS (new_sl) = 1;
285
  i->container = new_sl;
286
 
287
  STATEMENT_LIST_HEAD (new_sl) = cur;
288
  STATEMENT_LIST_TAIL (new_sl) = STATEMENT_LIST_TAIL (old_sl);
289
  STATEMENT_LIST_TAIL (old_sl) = prev;
290
  cur->prev = NULL;
291
  if (prev)
292
    prev->next = NULL;
293
 
294
  return new_sl;
295
}
296
 
297
/* Return the first expression in a sequence of COMPOUND_EXPRs,
298
   or in a STATEMENT_LIST.  */
299
 
300
tree
301
expr_first (tree expr)
302
{
303
  if (expr == NULL_TREE)
304
    return expr;
305
 
306
  if (TREE_CODE (expr) == STATEMENT_LIST)
307
    {
308
      struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (expr);
309
      return n ? n->stmt : NULL_TREE;
310
    }
311
 
312
  while (TREE_CODE (expr) == COMPOUND_EXPR)
313
    expr = TREE_OPERAND (expr, 0);
314
  return expr;
315
}
316
 
317
/* Return the last expression in a sequence of COMPOUND_EXPRs,
318
   or in a STATEMENT_LIST.  */
319
 
320
tree
321
expr_last (tree expr)
322
{
323
  if (expr == NULL_TREE)
324
    return expr;
325
 
326
  if (TREE_CODE (expr) == STATEMENT_LIST)
327
    {
328
      struct tree_statement_list_node *n = STATEMENT_LIST_TAIL (expr);
329
      return n ? n->stmt : NULL_TREE;
330
    }
331
 
332
  while (TREE_CODE (expr) == COMPOUND_EXPR)
333
    expr = TREE_OPERAND (expr, 1);
334
  return expr;
335
}
336
 
337
/* If EXPR is a single statement return it.  If EXPR is a
338
   STATEMENT_LIST containing exactly one statement S, return S.
339
   Otherwise, return NULL.  */
340
 
341
tree
342
expr_only (tree expr)
343
{
344
  if (expr == NULL_TREE)
345
    return NULL_TREE;
346
 
347
  if (TREE_CODE (expr) == STATEMENT_LIST)
348
    {
349
      struct tree_statement_list_node *n = STATEMENT_LIST_TAIL (expr);
350
      if (n && STATEMENT_LIST_HEAD (expr) == n)
351
        return n->stmt;
352
      else
353
        return NULL_TREE;
354
    }
355
 
356
  if (TREE_CODE (expr) == COMPOUND_EXPR)
357
    return NULL_TREE;
358
 
359
  return expr;
360
}
361
 
362
#include "gt-tree-iterator.h"

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