1 | /* Iterator routines for manipulating GENERIC and GIMPLE tree statements. |
2 | Copyright (C) 2003-2023 Free Software Foundation, Inc. |
3 | 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 |
8 | it under the terms of the GNU General Public License as published by |
9 | the Free Software Foundation; either version 3, or (at your option) |
10 | any later version. |
11 | |
12 | GCC is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 | GNU General Public License for more details. |
16 | |
17 | You should have received a copy of the GNU General Public License |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ |
20 | |
21 | #include "config.h" |
22 | #include "system.h" |
23 | #include "coretypes.h" |
24 | #include "tree.h" |
25 | #include "tree-iterator.h" |
26 | |
27 | |
28 | /* This is a cache of STATEMENT_LIST nodes. We create and destroy them |
29 | fairly often during gimplification. */ |
30 | |
31 | static GTY ((deletable ("" ))) vec<tree, va_gc> *stmt_list_cache; |
32 | |
33 | tree |
34 | alloc_stmt_list (void) |
35 | { |
36 | tree list; |
37 | if (!vec_safe_is_empty (v: stmt_list_cache)) |
38 | { |
39 | list = stmt_list_cache->pop (); |
40 | memset (s: list, c: 0, n: sizeof (struct tree_base)); |
41 | TREE_SET_CODE (list, STATEMENT_LIST); |
42 | } |
43 | else |
44 | { |
45 | list = make_node (STATEMENT_LIST); |
46 | TREE_SIDE_EFFECTS (list) = 0; |
47 | } |
48 | TREE_TYPE (list) = void_type_node; |
49 | return list; |
50 | } |
51 | |
52 | void |
53 | free_stmt_list (tree t) |
54 | { |
55 | gcc_assert (!STATEMENT_LIST_HEAD (t)); |
56 | gcc_assert (!STATEMENT_LIST_TAIL (t)); |
57 | vec_safe_push (v&: stmt_list_cache, obj: t); |
58 | } |
59 | |
60 | /* A subroutine of append_to_statement_list{,_force}. T is not NULL. */ |
61 | |
62 | static void |
63 | append_to_statement_list_1 (tree t, tree *list_p) |
64 | { |
65 | tree list = *list_p; |
66 | tree_stmt_iterator i; |
67 | |
68 | if (!list) |
69 | { |
70 | if (t && TREE_CODE (t) == STATEMENT_LIST) |
71 | { |
72 | *list_p = t; |
73 | return; |
74 | } |
75 | *list_p = list = alloc_stmt_list (); |
76 | } |
77 | else if (TREE_CODE (list) != STATEMENT_LIST) |
78 | { |
79 | tree first = list; |
80 | *list_p = list = alloc_stmt_list (); |
81 | i = tsi_last (t: list); |
82 | tsi_link_after (&i, first, TSI_CONTINUE_LINKING); |
83 | } |
84 | |
85 | i = tsi_last (t: list); |
86 | tsi_link_after (&i, t, TSI_CONTINUE_LINKING); |
87 | } |
88 | |
89 | /* Add T to the end of the list container pointed to by LIST_P. |
90 | If T is an expression with no effects, it is ignored. */ |
91 | |
92 | void |
93 | append_to_statement_list (tree t, tree *list_p) |
94 | { |
95 | if (t && (TREE_SIDE_EFFECTS (t) || TREE_CODE (t) == DEBUG_BEGIN_STMT)) |
96 | append_to_statement_list_1 (t, list_p); |
97 | } |
98 | |
99 | /* Similar, but the statement is always added, regardless of side effects. */ |
100 | |
101 | void |
102 | append_to_statement_list_force (tree t, tree *list_p) |
103 | { |
104 | if (t != NULL_TREE) |
105 | append_to_statement_list_1 (t, list_p); |
106 | } |
107 | |
108 | /* Links a statement, or a chain of statements, before the current stmt. */ |
109 | |
110 | void |
111 | tsi_link_before (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode) |
112 | { |
113 | struct tree_statement_list_node *head, *tail, *cur; |
114 | |
115 | /* Die on looping. */ |
116 | gcc_assert (t != i->container); |
117 | |
118 | if (TREE_CODE (t) == STATEMENT_LIST) |
119 | { |
120 | head = STATEMENT_LIST_HEAD (t); |
121 | tail = STATEMENT_LIST_TAIL (t); |
122 | STATEMENT_LIST_HEAD (t) = NULL; |
123 | STATEMENT_LIST_TAIL (t) = NULL; |
124 | |
125 | free_stmt_list (t); |
126 | |
127 | /* Empty statement lists need no work. */ |
128 | if (!head || !tail) |
129 | { |
130 | gcc_assert (head == tail); |
131 | return; |
132 | } |
133 | } |
134 | else |
135 | { |
136 | head = ggc_alloc<tree_statement_list_node> (); |
137 | head->prev = NULL; |
138 | head->next = NULL; |
139 | head->stmt = t; |
140 | tail = head; |
141 | } |
142 | |
143 | if (TREE_CODE (t) != DEBUG_BEGIN_STMT) |
144 | TREE_SIDE_EFFECTS (i->container) = 1; |
145 | |
146 | cur = i->ptr; |
147 | |
148 | /* Link it into the list. */ |
149 | if (cur) |
150 | { |
151 | head->prev = cur->prev; |
152 | if (head->prev) |
153 | head->prev->next = head; |
154 | else |
155 | STATEMENT_LIST_HEAD (i->container) = head; |
156 | tail->next = cur; |
157 | cur->prev = tail; |
158 | } |
159 | else |
160 | { |
161 | head->prev = STATEMENT_LIST_TAIL (i->container); |
162 | if (head->prev) |
163 | head->prev->next = head; |
164 | else |
165 | STATEMENT_LIST_HEAD (i->container) = head; |
166 | STATEMENT_LIST_TAIL (i->container) = tail; |
167 | } |
168 | |
169 | /* Update the iterator, if requested. */ |
170 | switch (mode) |
171 | { |
172 | case TSI_NEW_STMT: |
173 | case TSI_CONTINUE_LINKING: |
174 | case TSI_CHAIN_START: |
175 | i->ptr = head; |
176 | break; |
177 | case TSI_CHAIN_END: |
178 | i->ptr = tail; |
179 | break; |
180 | case TSI_SAME_STMT: |
181 | break; |
182 | } |
183 | } |
184 | |
185 | /* Links a statement, or a chain of statements, after the current stmt. */ |
186 | |
187 | void |
188 | tsi_link_after (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode) |
189 | { |
190 | struct tree_statement_list_node *head, *tail, *cur; |
191 | |
192 | /* Die on looping. */ |
193 | gcc_assert (t != i->container); |
194 | |
195 | if (TREE_CODE (t) == STATEMENT_LIST) |
196 | { |
197 | head = STATEMENT_LIST_HEAD (t); |
198 | tail = STATEMENT_LIST_TAIL (t); |
199 | STATEMENT_LIST_HEAD (t) = NULL; |
200 | STATEMENT_LIST_TAIL (t) = NULL; |
201 | |
202 | free_stmt_list (t); |
203 | |
204 | /* Empty statement lists need no work. */ |
205 | if (!head || !tail) |
206 | { |
207 | gcc_assert (head == tail); |
208 | return; |
209 | } |
210 | } |
211 | else |
212 | { |
213 | head = ggc_alloc<tree_statement_list_node> (); |
214 | head->prev = NULL; |
215 | head->next = NULL; |
216 | head->stmt = t; |
217 | tail = head; |
218 | } |
219 | |
220 | if (TREE_CODE (t) != DEBUG_BEGIN_STMT) |
221 | TREE_SIDE_EFFECTS (i->container) = 1; |
222 | |
223 | cur = i->ptr; |
224 | |
225 | /* Link it into the list. */ |
226 | if (cur) |
227 | { |
228 | tail->next = cur->next; |
229 | if (tail->next) |
230 | tail->next->prev = tail; |
231 | else |
232 | STATEMENT_LIST_TAIL (i->container) = tail; |
233 | head->prev = cur; |
234 | cur->next = head; |
235 | } |
236 | else |
237 | { |
238 | gcc_assert (!STATEMENT_LIST_TAIL (i->container)); |
239 | STATEMENT_LIST_HEAD (i->container) = head; |
240 | STATEMENT_LIST_TAIL (i->container) = tail; |
241 | } |
242 | |
243 | /* Update the iterator, if requested. */ |
244 | switch (mode) |
245 | { |
246 | case TSI_NEW_STMT: |
247 | case TSI_CHAIN_START: |
248 | i->ptr = head; |
249 | break; |
250 | case TSI_CONTINUE_LINKING: |
251 | case TSI_CHAIN_END: |
252 | i->ptr = tail; |
253 | break; |
254 | case TSI_SAME_STMT: |
255 | gcc_assert (cur); |
256 | break; |
257 | } |
258 | } |
259 | |
260 | /* Remove a stmt from the tree list. The iterator is updated to point to |
261 | the next stmt. */ |
262 | |
263 | void |
264 | tsi_delink (tree_stmt_iterator *i) |
265 | { |
266 | struct tree_statement_list_node *cur, *next, *prev; |
267 | |
268 | cur = i->ptr; |
269 | next = cur->next; |
270 | prev = cur->prev; |
271 | |
272 | if (prev) |
273 | prev->next = next; |
274 | else |
275 | STATEMENT_LIST_HEAD (i->container) = next; |
276 | if (next) |
277 | next->prev = prev; |
278 | else |
279 | STATEMENT_LIST_TAIL (i->container) = prev; |
280 | |
281 | if (!next && !prev) |
282 | TREE_SIDE_EFFECTS (i->container) = 0; |
283 | |
284 | i->ptr = next; |
285 | } |
286 | |
287 | /* Return the first expression in a sequence of COMPOUND_EXPRs, or in |
288 | a STATEMENT_LIST, disregarding DEBUG_BEGIN_STMTs, recursing into a |
289 | STATEMENT_LIST if that's the first non-DEBUG_BEGIN_STMT. */ |
290 | |
291 | tree |
292 | expr_first (tree expr) |
293 | { |
294 | if (expr == NULL_TREE) |
295 | return expr; |
296 | |
297 | if (TREE_CODE (expr) == STATEMENT_LIST) |
298 | { |
299 | struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (expr); |
300 | if (!n) |
301 | return NULL_TREE; |
302 | while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) |
303 | { |
304 | n = n->next; |
305 | if (!n) |
306 | return NULL_TREE; |
307 | } |
308 | /* If the first non-debug stmt is not a statement list, we |
309 | already know it's what we're looking for. */ |
310 | if (TREE_CODE (n->stmt) != STATEMENT_LIST) |
311 | return n->stmt; |
312 | |
313 | return expr_first (expr: n->stmt); |
314 | } |
315 | |
316 | while (TREE_CODE (expr) == COMPOUND_EXPR) |
317 | expr = TREE_OPERAND (expr, 0); |
318 | |
319 | return expr; |
320 | } |
321 | |
322 | /* Return the last expression in a sequence of COMPOUND_EXPRs, or in a |
323 | STATEMENT_LIST, disregarding DEBUG_BEGIN_STMTs, recursing into a |
324 | STATEMENT_LIST if that's the last non-DEBUG_BEGIN_STMT. */ |
325 | |
326 | tree |
327 | expr_last (tree expr) |
328 | { |
329 | if (expr == NULL_TREE) |
330 | return expr; |
331 | |
332 | if (TREE_CODE (expr) == STATEMENT_LIST) |
333 | { |
334 | struct tree_statement_list_node *n = STATEMENT_LIST_TAIL (expr); |
335 | if (!n) |
336 | return NULL_TREE; |
337 | while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) |
338 | { |
339 | n = n->prev; |
340 | if (!n) |
341 | return NULL_TREE; |
342 | } |
343 | /* If the last non-debug stmt is not a statement list, we |
344 | already know it's what we're looking for. */ |
345 | if (TREE_CODE (n->stmt) != STATEMENT_LIST) |
346 | return n->stmt; |
347 | |
348 | return expr_last (expr: n->stmt); |
349 | } |
350 | |
351 | while (TREE_CODE (expr) == COMPOUND_EXPR) |
352 | expr = TREE_OPERAND (expr, 1); |
353 | |
354 | return expr; |
355 | } |
356 | |
357 | /* If EXPR is a STATEMENT_LIST containing just DEBUG_BEGIN_STMTs and |
358 | a single other stmt, return that other stmt (recursively). |
359 | If it is a STATEMENT_LIST containing no non-DEBUG_BEGIN_STMTs or |
360 | multiple, return NULL_TREE. |
361 | Otherwise return EXPR. */ |
362 | |
363 | tree |
364 | expr_single (tree expr) |
365 | { |
366 | if (expr == NULL_TREE) |
367 | return expr; |
368 | |
369 | if (TREE_CODE (expr) == STATEMENT_LIST) |
370 | { |
371 | /* With -gstatement-frontiers we could have a STATEMENT_LIST with |
372 | DEBUG_BEGIN_STMT(s) and only a single other stmt, which with |
373 | -g wouldn't be present and we'd have that single other stmt |
374 | directly instead. */ |
375 | struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (expr); |
376 | if (!n) |
377 | return NULL_TREE; |
378 | while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) |
379 | { |
380 | n = n->next; |
381 | if (!n) |
382 | return NULL_TREE; |
383 | } |
384 | expr = n->stmt; |
385 | do |
386 | { |
387 | n = n->next; |
388 | if (!n) |
389 | return expr_single (expr); |
390 | } |
391 | while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT); |
392 | return NULL_TREE; |
393 | } |
394 | |
395 | return expr; |
396 | } |
397 | |
398 | #include "gt-tree-iterator.h" |
399 | |