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1 : : /* Common block and equivalence list handling
2 : : Copyright (C) 2000-2024 Free Software Foundation, Inc.
3 : : Contributed by Canqun Yang <canqun@nudt.edu.cn>
4 : :
5 : : This file is part of GCC.
6 : :
7 : : GCC is free software; you can redistribute it and/or modify it under
8 : : the terms of the GNU General Public License as published by the Free
9 : : Software Foundation; either version 3, or (at your option) any later
10 : : version.
11 : :
12 : : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 : : WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 : : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 : : 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 : : /* The core algorithm is based on Andy Vaught's g95 tree. Also the
22 : : way to build UNION_TYPE is borrowed from Richard Henderson.
23 : :
24 : : Transform common blocks. An integral part of this is processing
25 : : equivalence variables. Equivalenced variables that are not in a
26 : : common block end up in a private block of their own.
27 : :
28 : : Each common block or local equivalence list is declared as a union.
29 : : Variables within the block are represented as a field within the
30 : : block with the proper offset.
31 : :
32 : : So if two variables are equivalenced, they just point to a common
33 : : area in memory.
34 : :
35 : : Mathematically, laying out an equivalence block is equivalent to
36 : : solving a linear system of equations. The matrix is usually a
37 : : sparse matrix in which each row contains all zero elements except
38 : : for a +1 and a -1, a sort of a generalized Vandermonde matrix. The
39 : : matrix is usually block diagonal. The system can be
40 : : overdetermined, underdetermined or have a unique solution. If the
41 : : system is inconsistent, the program is not standard conforming.
42 : : The solution vector is integral, since all of the pivots are +1 or -1.
43 : :
44 : : How we lay out an equivalence block is a little less complicated.
45 : : In an equivalence list with n elements, there are n-1 conditions to
46 : : be satisfied. The conditions partition the variables into what we
47 : : will call segments. If A and B are equivalenced then A and B are
48 : : in the same segment. If B and C are equivalenced as well, then A,
49 : : B and C are in a segment and so on. Each segment is a block of
50 : : memory that has one or more variables equivalenced in some way. A
51 : : common block is made up of a series of segments that are joined one
52 : : after the other. In the linear system, a segment is a block
53 : : diagonal.
54 : :
55 : : To lay out a segment we first start with some variable and
56 : : determine its length. The first variable is assumed to start at
57 : : offset one and extends to however long it is. We then traverse the
58 : : list of equivalences to find an unused condition that involves at
59 : : least one of the variables currently in the segment.
60 : :
61 : : Each equivalence condition amounts to the condition B+b=C+c where B
62 : : and C are the offsets of the B and C variables, and b and c are
63 : : constants which are nonzero for array elements, substrings or
64 : : structure components. So for
65 : :
66 : : EQUIVALENCE(B(2), C(3))
67 : : we have
68 : : B + 2*size of B's elements = C + 3*size of C's elements.
69 : :
70 : : If B and C are known we check to see if the condition already
71 : : holds. If B is known we can solve for C. Since we know the length
72 : : of C, we can see if the minimum and maximum extents of the segment
73 : : are affected. Eventually, we make a full pass through the
74 : : equivalence list without finding any new conditions and the segment
75 : : is fully specified.
76 : :
77 : : At this point, the segment is added to the current common block.
78 : : Since we know the minimum extent of the segment, everything in the
79 : : segment is translated to its position in the common block. The
80 : : usual case here is that there are no equivalence statements and the
81 : : common block is series of segments with one variable each, which is
82 : : a diagonal matrix in the matrix formulation.
83 : :
84 : : Each segment is described by a chain of segment_info structures. Each
85 : : segment_info structure describes the extents of a single variable within
86 : : the segment. This list is maintained in the order the elements are
87 : : positioned within the segment. If two elements have the same starting
88 : : offset the smaller will come first. If they also have the same size their
89 : : ordering is undefined.
90 : :
91 : : Once all common blocks have been created, the list of equivalences
92 : : is examined for still-unused equivalence conditions. We create a
93 : : block for each merged equivalence list. */
94 : :
95 : : #include "config.h"
96 : : #define INCLUDE_MAP
97 : : #include "system.h"
98 : : #include "coretypes.h"
99 : : #include "tm.h"
100 : : #include "tree.h"
101 : : #include "gfortran.h"
102 : : #include "trans.h"
103 : : #include "stringpool.h"
104 : : #include "fold-const.h"
105 : : #include "stor-layout.h"
106 : : #include "varasm.h"
107 : : #include "trans-types.h"
108 : : #include "trans-const.h"
109 : : #include "target-memory.h"
110 : :
111 : :
112 : : /* Holds a single variable in an equivalence set. */
113 : : typedef struct segment_info
114 : : {
115 : : gfc_symbol *sym;
116 : : HOST_WIDE_INT offset;
117 : : HOST_WIDE_INT length;
118 : : /* This will contain the field type until the field is created. */
119 : : tree field;
120 : : struct segment_info *next;
121 : : } segment_info;
122 : :
123 : : static segment_info * current_segment;
124 : :
125 : : /* Store decl of all common blocks in this translation unit; the first
126 : : tree is the identifier. */
127 : : static std::map<tree, tree> gfc_map_of_all_commons;
128 : :
129 : :
130 : : /* Make a segment_info based on a symbol. */
131 : :
132 : : static segment_info *
133 : 8224 : get_segment_info (gfc_symbol * sym, HOST_WIDE_INT offset)
134 : : {
135 : 8224 : segment_info *s;
136 : :
137 : : /* Make sure we've got the character length. */
138 : 8224 : if (sym->ts.type == BT_CHARACTER)
139 : 641 : gfc_conv_const_charlen (sym->ts.u.cl);
140 : :
141 : : /* Create the segment_info and fill it in. */
142 : 8224 : s = XCNEW (segment_info);
143 : 8224 : s->sym = sym;
144 : : /* We will use this type when building the segment aggregate type. */
145 : 8224 : s->field = gfc_sym_type (sym);
146 : 8224 : s->length = int_size_in_bytes (s->field);
147 : 8224 : s->offset = offset;
148 : :
149 : 8224 : return s;
150 : : }
151 : :
152 : :
153 : : /* Add a copy of a segment list to the namespace. This is specifically for
154 : : equivalence segments, so that dependency checking can be done on
155 : : equivalence group members. */
156 : :
157 : : static void
158 : 6648 : copy_equiv_list_to_ns (segment_info *c)
159 : : {
160 : 6648 : segment_info *f;
161 : 6648 : gfc_equiv_info *s;
162 : 6648 : gfc_equiv_list *l;
163 : :
164 : 6648 : l = XCNEW (gfc_equiv_list);
165 : :
166 : 6648 : l->next = c->sym->ns->equiv_lists;
167 : 6648 : c->sym->ns->equiv_lists = l;
168 : :
169 : 14872 : for (f = c; f; f = f->next)
170 : : {
171 : 8224 : s = XCNEW (gfc_equiv_info);
172 : 8224 : s->next = l->equiv;
173 : 8224 : l->equiv = s;
174 : 8224 : s->sym = f->sym;
175 : 8224 : s->offset = f->offset;
176 : 8224 : s->length = f->length;
177 : : }
178 : 6648 : }
179 : :
180 : :
181 : : /* Add combine segment V and segment LIST. */
182 : :
183 : : static segment_info *
184 : 7421 : add_segments (segment_info *list, segment_info *v)
185 : : {
186 : 7421 : segment_info *s;
187 : 7421 : segment_info *p;
188 : 7421 : segment_info *next;
189 : :
190 : 7421 : p = NULL;
191 : 7421 : s = list;
192 : :
193 : 15189 : while (v)
194 : : {
195 : : /* Find the location of the new element. */
196 : 42291 : while (s)
197 : : {
198 : 35646 : if (v->offset < s->offset)
199 : : break;
200 : 35214 : if (v->offset == s->offset
201 : 737 : && v->length <= s->length)
202 : : break;
203 : :
204 : 34523 : p = s;
205 : 34523 : s = s->next;
206 : : }
207 : :
208 : : /* Insert the new element in between p and s. */
209 : 7768 : next = v->next;
210 : 7768 : v->next = s;
211 : 7768 : if (p == NULL)
212 : : list = v;
213 : : else
214 : 4806 : p->next = v;
215 : :
216 : : p = v;
217 : : v = next;
218 : : }
219 : :
220 : 7421 : return list;
221 : : }
222 : :
223 : :
224 : : /* Construct mangled common block name from symbol name. */
225 : :
226 : : /* We need the bind(c) flag to tell us how/if we should mangle the symbol
227 : : name. There are few calls to this function, so few places that this
228 : : would need to be added. At the moment, there is only one call, in
229 : : build_common_decl(). We can't attempt to look up the common block
230 : : because we may be building it for the first time and therefore, it won't
231 : : be in the common_root. We also need the binding label, if it's bind(c).
232 : : Therefore, send in the pointer to the common block, so whatever info we
233 : : have so far can be used. All of the necessary info should be available
234 : : in the gfc_common_head by now, so it should be accurate to test the
235 : : isBindC flag and use the binding label given if it is bind(c).
236 : :
237 : : We may NOT know yet if it's bind(c) or not, but we can try at least.
238 : : Will have to figure out what to do later if it's labeled bind(c)
239 : : after this is called. */
240 : :
241 : : static tree
242 : 2109 : gfc_sym_mangled_common_id (gfc_common_head *com)
243 : : {
244 : 2109 : int has_underscore;
245 : : /* Provide sufficient space to hold "symbol.symbol.eq.1234567890__". */
246 : 2109 : char mangled_name[2*GFC_MAX_MANGLED_SYMBOL_LEN + 1 + 16 + 1];
247 : 2109 : char name[sizeof (mangled_name) - 2];
248 : :
249 : : /* Get the name out of the common block pointer. */
250 : 2109 : size_t len = strlen (com->name);
251 : 2109 : gcc_assert (len < sizeof (name));
252 : 2109 : strcpy (name, com->name);
253 : :
254 : : /* If we're suppose to do a bind(c). */
255 : 2109 : if (com->is_bind_c == 1 && com->binding_label)
256 : 69 : return get_identifier (com->binding_label);
257 : :
258 : 2040 : if (strcmp (name, BLANK_COMMON_NAME) == 0)
259 : 212 : return get_identifier (name);
260 : :
261 : 1828 : if (flag_underscoring)
262 : : {
263 : 1828 : has_underscore = strchr (name, '_') != 0;
264 : 1828 : if (flag_second_underscore && has_underscore)
265 : 4 : snprintf (mangled_name, sizeof mangled_name, "%s__", name);
266 : : else
267 : 1824 : snprintf (mangled_name, sizeof mangled_name, "%s_", name);
268 : :
269 : 1828 : return get_identifier (mangled_name);
270 : : }
271 : : else
272 : 0 : return get_identifier (name);
273 : : }
274 : :
275 : :
276 : : /* Build a field declaration for a common variable or a local equivalence
277 : : object. */
278 : :
279 : : static void
280 : 8224 : build_field (segment_info *h, tree union_type, record_layout_info rli)
281 : : {
282 : 8224 : tree field;
283 : 8224 : tree name;
284 : 8224 : HOST_WIDE_INT offset = h->offset;
285 : 8224 : unsigned HOST_WIDE_INT desired_align, known_align;
286 : :
287 : 8224 : name = get_identifier (h->sym->name);
288 : 8224 : field = build_decl (gfc_get_location (&h->sym->declared_at),
289 : : FIELD_DECL, name, h->field);
290 : 8224 : known_align = (offset & -offset) * BITS_PER_UNIT;
291 : 13042 : if (known_align == 0 || known_align > BIGGEST_ALIGNMENT)
292 : 5003 : known_align = BIGGEST_ALIGNMENT;
293 : :
294 : 8224 : desired_align = update_alignment_for_field (rli, field, known_align);
295 : 8224 : if (desired_align > known_align)
296 : 7 : DECL_PACKED (field) = 1;
297 : :
298 : 8224 : DECL_FIELD_CONTEXT (field) = union_type;
299 : 8224 : DECL_FIELD_OFFSET (field) = size_int (offset);
300 : 8224 : DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
301 : 8224 : SET_DECL_OFFSET_ALIGN (field, known_align);
302 : :
303 : 8224 : rli->offset = size_binop (MAX_EXPR, rli->offset,
304 : : size_binop (PLUS_EXPR,
305 : : DECL_FIELD_OFFSET (field),
306 : : DECL_SIZE_UNIT (field)));
307 : : /* If this field is assigned to a label, we create another two variables.
308 : : One will hold the address of target label or format label. The other will
309 : : hold the length of format label string. */
310 : 8224 : if (h->sym->attr.assign)
311 : : {
312 : 14 : tree len;
313 : 14 : tree addr;
314 : :
315 : 14 : gfc_allocate_lang_decl (field);
316 : 14 : GFC_DECL_ASSIGN (field) = 1;
317 : 14 : len = gfc_create_var_np (gfc_charlen_type_node,h->sym->name);
318 : 14 : addr = gfc_create_var_np (pvoid_type_node, h->sym->name);
319 : 14 : TREE_STATIC (len) = 1;
320 : 14 : TREE_STATIC (addr) = 1;
321 : 14 : DECL_INITIAL (len) = build_int_cst (gfc_charlen_type_node, -2);
322 : 14 : gfc_set_decl_location (len, &h->sym->declared_at);
323 : 14 : gfc_set_decl_location (addr, &h->sym->declared_at);
324 : 14 : GFC_DECL_STRING_LEN (field) = pushdecl_top_level (len);
325 : 14 : GFC_DECL_ASSIGN_ADDR (field) = pushdecl_top_level (addr);
326 : : }
327 : :
328 : : /* If this field is volatile, mark it. */
329 : 8224 : if (h->sym->attr.volatile_)
330 : : {
331 : 3 : tree new_type;
332 : 3 : TREE_THIS_VOLATILE (field) = 1;
333 : 3 : TREE_SIDE_EFFECTS (field) = 1;
334 : 3 : new_type = build_qualified_type (TREE_TYPE (field), TYPE_QUAL_VOLATILE);
335 : 3 : TREE_TYPE (field) = new_type;
336 : : }
337 : :
338 : 8224 : h->field = field;
339 : 8224 : }
340 : :
341 : : #if !defined (NO_DOT_IN_LABEL)
342 : : #define GFC_EQUIV_FMT "equiv.%d"
343 : : #elif !defined (NO_DOLLAR_IN_LABEL)
344 : : #define GFC_EQUIV_FMT "_Equiv$%d"
345 : : #else
346 : : #define GFC_EQUIV_FMT "_Equiv_%d"
347 : : #endif
348 : :
349 : : /* Get storage for local equivalence. */
350 : :
351 : : static tree
352 : 698 : build_equiv_decl (tree union_type, bool is_init, bool is_saved, bool is_auto)
353 : : {
354 : 698 : tree decl;
355 : 698 : char name[18];
356 : 698 : static int serial = 0;
357 : :
358 : 698 : if (is_init)
359 : : {
360 : 146 : decl = gfc_create_var (union_type, "equiv");
361 : 146 : TREE_STATIC (decl) = 1;
362 : 146 : GFC_DECL_COMMON_OR_EQUIV (decl) = 1;
363 : 146 : return decl;
364 : : }
365 : :
366 : 552 : snprintf (name, sizeof (name), GFC_EQUIV_FMT, serial++);
367 : 552 : decl = build_decl (input_location,
368 : : VAR_DECL, get_identifier (name), union_type);
369 : 552 : DECL_ARTIFICIAL (decl) = 1;
370 : 552 : DECL_IGNORED_P (decl) = 1;
371 : :
372 : 552 : if (!is_auto && (!gfc_can_put_var_on_stack (DECL_SIZE_UNIT (decl))
373 : 531 : || is_saved))
374 : 27 : TREE_STATIC (decl) = 1;
375 : :
376 : 552 : TREE_ADDRESSABLE (decl) = 1;
377 : 552 : TREE_USED (decl) = 1;
378 : 552 : GFC_DECL_COMMON_OR_EQUIV (decl) = 1;
379 : :
380 : : /* The source location has been lost, and doesn't really matter.
381 : : We need to set it to something though. */
382 : 552 : gfc_set_decl_location (decl, &gfc_current_locus);
383 : :
384 : 552 : gfc_add_decl_to_function (decl);
385 : :
386 : 552 : return decl;
387 : : }
388 : :
389 : :
390 : : /* Get storage for common block. */
391 : :
392 : : static tree
393 : 2109 : build_common_decl (gfc_common_head *com, tree union_type, bool is_init)
394 : : {
395 : 2109 : tree decl, identifier;
396 : :
397 : 2109 : identifier = gfc_sym_mangled_common_id (com);
398 : 2109 : decl = gfc_map_of_all_commons.count(identifier)
399 : 992 : ? gfc_map_of_all_commons[identifier] : NULL_TREE;
400 : :
401 : : /* Update the size of this common block as needed. */
402 : 2109 : if (decl != NULL_TREE)
403 : : {
404 : 992 : tree size = TYPE_SIZE_UNIT (union_type);
405 : :
406 : : /* Named common blocks of the same name shall be of the same size
407 : : in all scoping units of a program in which they appear, but
408 : : blank common blocks may be of different sizes. */
409 : 992 : if (!tree_int_cst_equal (DECL_SIZE_UNIT (decl), size)
410 : 992 : && strcmp (com->name, BLANK_COMMON_NAME))
411 : 45 : gfc_warning (0, "Named COMMON block %qs at %L shall be of the "
412 : : "same size as elsewhere (%wu vs %wu bytes)", com->name,
413 : : &com->where,
414 : 15 : TREE_INT_CST_LOW (size),
415 : 15 : TREE_INT_CST_LOW (DECL_SIZE_UNIT (decl)));
416 : :
417 : 992 : if (tree_int_cst_lt (DECL_SIZE_UNIT (decl), size))
418 : : {
419 : 11 : DECL_SIZE (decl) = TYPE_SIZE (union_type);
420 : 11 : DECL_SIZE_UNIT (decl) = size;
421 : 11 : SET_DECL_MODE (decl, TYPE_MODE (union_type));
422 : 11 : TREE_TYPE (decl) = union_type;
423 : 11 : layout_decl (decl, 0);
424 : : }
425 : : }
426 : :
427 : : /* If this common block has been declared in a previous program unit,
428 : : and either it is already initialized or there is no new initialization
429 : : for it, just return. */
430 : 992 : if ((decl != NULL_TREE) && (!is_init || DECL_INITIAL (decl)))
431 : : return decl;
432 : :
433 : : /* If there is no backend_decl for the common block, build it. */
434 : 1135 : if (decl == NULL_TREE)
435 : : {
436 : 1117 : tree omp_clauses = NULL_TREE;
437 : :
438 : 1117 : if (com->is_bind_c == 1 && com->binding_label)
439 : 51 : decl = build_decl (input_location, VAR_DECL, identifier, union_type);
440 : : else
441 : : {
442 : 1066 : decl = build_decl (input_location, VAR_DECL, get_identifier (com->name),
443 : : union_type);
444 : 1066 : gfc_set_decl_assembler_name (decl, identifier);
445 : : }
446 : :
447 : 1117 : TREE_PUBLIC (decl) = 1;
448 : 1117 : TREE_STATIC (decl) = 1;
449 : 1117 : DECL_IGNORED_P (decl) = 1;
450 : 1117 : if (!com->is_bind_c)
451 : 2103 : SET_DECL_ALIGN (decl, BIGGEST_ALIGNMENT);
452 : : else
453 : : {
454 : : /* Do not set the alignment for bind(c) common blocks to
455 : : BIGGEST_ALIGNMENT because that won't match what C does. Also,
456 : : for common blocks with one element, the alignment must be
457 : : that of the field within the common block in order to match
458 : : what C will do. */
459 : 59 : tree field = NULL_TREE;
460 : 59 : field = TYPE_FIELDS (TREE_TYPE (decl));
461 : 59 : if (DECL_CHAIN (field) == NULL_TREE)
462 : 23 : SET_DECL_ALIGN (decl, TYPE_ALIGN (TREE_TYPE (field)));
463 : : }
464 : 1117 : DECL_USER_ALIGN (decl) = 0;
465 : 1117 : GFC_DECL_COMMON_OR_EQUIV (decl) = 1;
466 : :
467 : 1117 : gfc_set_decl_location (decl, &com->where);
468 : :
469 : 1117 : if (com->threadprivate)
470 : 42 : set_decl_tls_model (decl, decl_default_tls_model (decl));
471 : :
472 : 1117 : if (com->omp_device_type != OMP_DEVICE_TYPE_UNSET)
473 : : {
474 : 6 : tree c = build_omp_clause (UNKNOWN_LOCATION, OMP_CLAUSE_DEVICE_TYPE);
475 : 6 : switch (com->omp_device_type)
476 : : {
477 : 2 : case OMP_DEVICE_TYPE_HOST:
478 : 2 : OMP_CLAUSE_DEVICE_TYPE_KIND (c) = OMP_CLAUSE_DEVICE_TYPE_HOST;
479 : 2 : break;
480 : 2 : case OMP_DEVICE_TYPE_NOHOST:
481 : 2 : OMP_CLAUSE_DEVICE_TYPE_KIND (c) = OMP_CLAUSE_DEVICE_TYPE_NOHOST;
482 : 2 : break;
483 : 2 : case OMP_DEVICE_TYPE_ANY:
484 : 2 : OMP_CLAUSE_DEVICE_TYPE_KIND (c) = OMP_CLAUSE_DEVICE_TYPE_ANY;
485 : 2 : break;
486 : 0 : default:
487 : 0 : gcc_unreachable ();
488 : : }
489 : : omp_clauses = c;
490 : : }
491 : 1117 : if (com->omp_declare_target_link)
492 : 4 : DECL_ATTRIBUTES (decl)
493 : 8 : = tree_cons (get_identifier ("omp declare target link"),
494 : 4 : omp_clauses, DECL_ATTRIBUTES (decl));
495 : 1113 : else if (com->omp_declare_target)
496 : 5 : DECL_ATTRIBUTES (decl)
497 : 10 : = tree_cons (get_identifier ("omp declare target"),
498 : 5 : omp_clauses, DECL_ATTRIBUTES (decl));
499 : :
500 : : /* Place the back end declaration for this common block in
501 : : GLOBAL_BINDING_LEVEL. */
502 : 1117 : gfc_map_of_all_commons[identifier] = pushdecl_top_level (decl);
503 : : }
504 : :
505 : : /* Has no initial values. */
506 : 1135 : if (!is_init)
507 : : {
508 : 1033 : DECL_INITIAL (decl) = NULL_TREE;
509 : 1033 : DECL_COMMON (decl) = 1;
510 : 1033 : DECL_DEFER_OUTPUT (decl) = 1;
511 : : }
512 : : else
513 : : {
514 : 102 : DECL_INITIAL (decl) = error_mark_node;
515 : 102 : DECL_COMMON (decl) = 0;
516 : 102 : DECL_DEFER_OUTPUT (decl) = 0;
517 : : }
518 : : return decl;
519 : : }
520 : :
521 : :
522 : : /* Return a field that is the size of the union, if an equivalence has
523 : : overlapping initializers. Merge the initializers into a single
524 : : initializer for this new field, then free the old ones. */
525 : :
526 : : static tree
527 : 951 : get_init_field (segment_info *head, tree union_type, tree *field_init,
528 : : record_layout_info rli)
529 : : {
530 : 951 : segment_info *s;
531 : 951 : HOST_WIDE_INT length = 0;
532 : 951 : HOST_WIDE_INT offset = 0;
533 : 951 : unsigned HOST_WIDE_INT known_align, desired_align;
534 : 951 : bool overlap = false;
535 : 951 : tree tmp, field;
536 : 951 : tree init;
537 : 951 : unsigned char *data, *chk;
538 : 951 : vec<constructor_elt, va_gc> *v = NULL;
539 : :
540 : 951 : tree type = unsigned_char_type_node;
541 : 951 : int i;
542 : :
543 : : /* Obtain the size of the union and check if there are any overlapping
544 : : initializers. */
545 : 4105 : for (s = head; s; s = s->next)
546 : : {
547 : 3154 : HOST_WIDE_INT slen = s->offset + s->length;
548 : 3154 : if (s->sym->value)
549 : : {
550 : 234 : if (s->offset < offset)
551 : 50 : overlap = true;
552 : : offset = slen;
553 : : }
554 : 3154 : length = length < slen ? slen : length;
555 : : }
556 : :
557 : 951 : if (!overlap)
558 : : return NULL_TREE;
559 : :
560 : : /* Now absorb all the initializer data into a single vector,
561 : : whilst checking for overlapping, unequal values. */
562 : 46 : data = XCNEWVEC (unsigned char, (size_t)length);
563 : 46 : chk = XCNEWVEC (unsigned char, (size_t)length);
564 : :
565 : : /* TODO - change this when default initialization is implemented. */
566 : 46 : memset (data, '\0', (size_t)length);
567 : 46 : memset (chk, '\0', (size_t)length);
568 : 156 : for (s = head; s; s = s->next)
569 : 110 : if (s->sym->value)
570 : : {
571 : 96 : locus *loc = NULL;
572 : 96 : if (s->sym->ns->equiv && s->sym->ns->equiv->eq)
573 : 96 : loc = &s->sym->ns->equiv->eq->expr->where;
574 : 96 : gfc_merge_initializers (s->sym->ts, s->sym->value, loc,
575 : : &data[s->offset],
576 : 96 : &chk[s->offset],
577 : 96 : (size_t)s->length);
578 : : }
579 : :
580 : 1142 : for (i = 0; i < length; i++)
581 : 1096 : CONSTRUCTOR_APPEND_ELT (v, NULL, build_int_cst (type, data[i]));
582 : :
583 : 46 : free (data);
584 : 46 : free (chk);
585 : :
586 : : /* Build a char[length] array to hold the initializers. Much of what
587 : : follows is borrowed from build_field, above. */
588 : :
589 : 46 : tmp = build_int_cst (gfc_array_index_type, length - 1);
590 : 46 : tmp = build_range_type (gfc_array_index_type,
591 : : gfc_index_zero_node, tmp);
592 : 46 : tmp = build_array_type (type, tmp);
593 : 46 : field = build_decl (gfc_get_location (&gfc_current_locus),
594 : : FIELD_DECL, NULL_TREE, tmp);
595 : :
596 : 46 : known_align = BIGGEST_ALIGNMENT;
597 : :
598 : 46 : desired_align = update_alignment_for_field (rli, field, known_align);
599 : 46 : if (desired_align > known_align)
600 : 0 : DECL_PACKED (field) = 1;
601 : :
602 : 46 : DECL_FIELD_CONTEXT (field) = union_type;
603 : 46 : DECL_FIELD_OFFSET (field) = size_int (0);
604 : 46 : DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
605 : 46 : SET_DECL_OFFSET_ALIGN (field, known_align);
606 : :
607 : 46 : rli->offset = size_binop (MAX_EXPR, rli->offset,
608 : : size_binop (PLUS_EXPR,
609 : : DECL_FIELD_OFFSET (field),
610 : : DECL_SIZE_UNIT (field)));
611 : :
612 : 46 : init = build_constructor (TREE_TYPE (field), v);
613 : 46 : TREE_CONSTANT (init) = 1;
614 : :
615 : 46 : *field_init = init;
616 : :
617 : 156 : for (s = head; s; s = s->next)
618 : : {
619 : 110 : if (s->sym->value == NULL)
620 : 14 : continue;
621 : :
622 : 96 : gfc_free_expr (s->sym->value);
623 : 96 : s->sym->value = NULL;
624 : : }
625 : :
626 : : return field;
627 : : }
628 : :
629 : :
630 : : /* Declare memory for the common block or local equivalence, and create
631 : : backend declarations for all of the elements. */
632 : :
633 : : static void
634 : 2807 : create_common (gfc_common_head *com, segment_info *head, bool saw_equiv)
635 : : {
636 : 2807 : segment_info *s, *next_s;
637 : 2807 : tree union_type;
638 : 2807 : tree *field_link;
639 : 2807 : tree field;
640 : 2807 : tree field_init = NULL_TREE;
641 : 2807 : record_layout_info rli;
642 : 2807 : tree decl;
643 : 2807 : bool is_init = false;
644 : 2807 : bool is_saved = false;
645 : 2807 : bool is_auto = false;
646 : :
647 : : /* Declare the variables inside the common block.
648 : : If the current common block contains any equivalence object, then
649 : : make a UNION_TYPE node, otherwise RECORD_TYPE. This will let the
650 : : alias analyzer work well when there is no address overlapping for
651 : : common variables in the current common block. */
652 : 2807 : if (saw_equiv)
653 : 951 : union_type = make_node (UNION_TYPE);
654 : : else
655 : 1856 : union_type = make_node (RECORD_TYPE);
656 : :
657 : 2807 : rli = start_record_layout (union_type);
658 : 2807 : field_link = &TYPE_FIELDS (union_type);
659 : :
660 : : /* Check for overlapping initializers and replace them with a single,
661 : : artificial field that contains all the data. */
662 : 2807 : if (saw_equiv)
663 : 951 : field = get_init_field (head, union_type, &field_init, rli);
664 : : else
665 : : field = NULL_TREE;
666 : :
667 : 951 : if (field != NULL_TREE)
668 : : {
669 : 46 : is_init = true;
670 : 46 : *field_link = field;
671 : 46 : field_link = &DECL_CHAIN (field);
672 : : }
673 : :
674 : 11031 : for (s = head; s; s = s->next)
675 : : {
676 : 8224 : build_field (s, union_type, rli);
677 : :
678 : : /* Link the field into the type. */
679 : 8224 : *field_link = s->field;
680 : 8224 : field_link = &DECL_CHAIN (s->field);
681 : :
682 : : /* Has initial value. */
683 : 8224 : if (s->sym->value)
684 : 259 : is_init = true;
685 : :
686 : : /* Has SAVE attribute. */
687 : 8224 : if (s->sym->attr.save)
688 : 580 : is_saved = true;
689 : :
690 : : /* Has AUTOMATIC attribute. */
691 : 8224 : if (s->sym->attr.automatic)
692 : 14 : is_auto = true;
693 : : }
694 : :
695 : 2807 : finish_record_layout (rli, true);
696 : :
697 : 2807 : if (com)
698 : 2109 : decl = build_common_decl (com, union_type, is_init);
699 : : else
700 : 698 : decl = build_equiv_decl (union_type, is_init, is_saved, is_auto);
701 : :
702 : 2807 : if (is_init)
703 : : {
704 : 248 : tree ctor, tmp;
705 : 248 : vec<constructor_elt, va_gc> *v = NULL;
706 : :
707 : 248 : if (field != NULL_TREE && field_init != NULL_TREE)
708 : 46 : CONSTRUCTOR_APPEND_ELT (v, field, field_init);
709 : : else
710 : 620 : for (s = head; s; s = s->next)
711 : : {
712 : 418 : if (s->sym->value)
713 : : {
714 : : /* Add the initializer for this field. */
715 : 259 : tmp = gfc_conv_initializer (s->sym->value, &s->sym->ts,
716 : 259 : TREE_TYPE (s->field),
717 : : s->sym->attr.dimension,
718 : : s->sym->attr.pointer
719 : 259 : || s->sym->attr.allocatable, false);
720 : :
721 : 259 : CONSTRUCTOR_APPEND_ELT (v, s->field, tmp);
722 : : }
723 : : }
724 : :
725 : 248 : gcc_assert (!v->is_empty ());
726 : 248 : ctor = build_constructor (union_type, v);
727 : 248 : TREE_CONSTANT (ctor) = 1;
728 : 248 : TREE_STATIC (ctor) = 1;
729 : 248 : DECL_INITIAL (decl) = ctor;
730 : :
731 : 248 : if (flag_checking)
732 : : {
733 : : tree field, value;
734 : : unsigned HOST_WIDE_INT idx;
735 : 553 : FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), idx, field, value)
736 : 305 : gcc_assert (TREE_CODE (field) == FIELD_DECL);
737 : : }
738 : : }
739 : :
740 : : /* Build component reference for each variable. */
741 : 11031 : for (s = head; s; s = next_s)
742 : : {
743 : 8224 : tree var_decl;
744 : :
745 : 8224 : var_decl = build_decl (gfc_get_location (&s->sym->declared_at),
746 : 8224 : VAR_DECL, DECL_NAME (s->field),
747 : 8224 : TREE_TYPE (s->field));
748 : 8224 : TREE_STATIC (var_decl) = TREE_STATIC (decl);
749 : : /* Mark the variable as used in order to avoid warnings about
750 : : unused variables. */
751 : 8224 : TREE_USED (var_decl) = 1;
752 : 8224 : if (s->sym->attr.use_assoc)
753 : 436 : DECL_IGNORED_P (var_decl) = 1;
754 : 8224 : if (s->sym->attr.target)
755 : 66 : TREE_ADDRESSABLE (var_decl) = 1;
756 : : /* Fake variables are not visible from other translation units. */
757 : 8224 : TREE_PUBLIC (var_decl) = 0;
758 : 8224 : gfc_finish_decl_attrs (var_decl, &s->sym->attr);
759 : :
760 : : /* To preserve identifier names in COMMON, chain to procedure
761 : : scope unless at top level in a module definition. */
762 : 8224 : if (com
763 : 6439 : && s->sym->ns->proc_name
764 : 6368 : && s->sym->ns->proc_name->attr.flavor == FL_MODULE)
765 : 482 : var_decl = pushdecl_top_level (var_decl);
766 : : else
767 : 7742 : gfc_add_decl_to_function (var_decl);
768 : :
769 : 8224 : tree comp = build3_loc (input_location, COMPONENT_REF,
770 : 8224 : TREE_TYPE (s->field), decl, s->field, NULL_TREE);
771 : 8224 : if (TREE_THIS_VOLATILE (s->field))
772 : 3 : TREE_THIS_VOLATILE (comp) = 1;
773 : 8224 : SET_DECL_VALUE_EXPR (var_decl, comp);
774 : 8224 : DECL_HAS_VALUE_EXPR_P (var_decl) = 1;
775 : 8224 : GFC_DECL_COMMON_OR_EQUIV (var_decl) = 1;
776 : :
777 : 8224 : if (s->sym->attr.assign)
778 : : {
779 : 14 : gfc_allocate_lang_decl (var_decl);
780 : 14 : GFC_DECL_ASSIGN (var_decl) = 1;
781 : 14 : GFC_DECL_STRING_LEN (var_decl) = GFC_DECL_STRING_LEN (s->field);
782 : 14 : GFC_DECL_ASSIGN_ADDR (var_decl) = GFC_DECL_ASSIGN_ADDR (s->field);
783 : : }
784 : :
785 : 8224 : s->sym->backend_decl = var_decl;
786 : :
787 : 8224 : next_s = s->next;
788 : 8224 : free (s);
789 : : }
790 : 2807 : }
791 : :
792 : :
793 : : /* Given a symbol, find it in the current segment list. Returns NULL if
794 : : not found. */
795 : :
796 : : static segment_info *
797 : 7430 : find_segment_info (gfc_symbol *symbol)
798 : : {
799 : 7430 : segment_info *n;
800 : :
801 : 43560 : for (n = current_segment; n; n = n->next)
802 : : {
803 : 36139 : if (n->sym == symbol)
804 : 0 : return n;
805 : : }
806 : :
807 : : return NULL;
808 : : }
809 : :
810 : :
811 : : /* Given an expression node, make sure it is a constant integer and return
812 : : the mpz_t value. */
813 : :
814 : : static mpz_t *
815 : 6124 : get_mpz (gfc_expr *e)
816 : : {
817 : :
818 : 0 : if (e->expr_type != EXPR_CONSTANT)
819 : 0 : gfc_internal_error ("get_mpz(): Not an integer constant");
820 : :
821 : 6124 : return &e->value.integer;
822 : : }
823 : :
824 : :
825 : : /* Given an array specification and an array reference, figure out the
826 : : array element number (zero based). Bounds and elements are guaranteed
827 : : to be constants. If something goes wrong we generate an error and
828 : : return zero. */
829 : :
830 : : static HOST_WIDE_INT
831 : 1437 : element_number (gfc_array_ref *ar)
832 : : {
833 : 1437 : mpz_t multiplier, offset, extent, n;
834 : 1437 : gfc_array_spec *as;
835 : 1437 : HOST_WIDE_INT i, rank;
836 : :
837 : 1437 : as = ar->as;
838 : 1437 : rank = as->rank;
839 : 1437 : mpz_init_set_ui (multiplier, 1);
840 : 1437 : mpz_init_set_ui (offset, 0);
841 : 1437 : mpz_init (extent);
842 : 1437 : mpz_init (n);
843 : :
844 : 4321 : for (i = 0; i < rank; i++)
845 : : {
846 : 1447 : if (ar->dimen_type[i] != DIMEN_ELEMENT)
847 : 0 : gfc_internal_error ("element_number(): Bad dimension type");
848 : :
849 : 1447 : if (as && as->lower[i])
850 : 1446 : mpz_sub (n, *get_mpz (ar->start[i]), *get_mpz (as->lower[i]));
851 : : else
852 : 1 : mpz_sub_ui (n, *get_mpz (ar->start[i]), 1);
853 : :
854 : 1447 : mpz_mul (n, n, multiplier);
855 : 1447 : mpz_add (offset, offset, n);
856 : :
857 : 1447 : if (as && as->upper[i] && as->lower[i])
858 : : {
859 : 1446 : mpz_sub (extent, *get_mpz (as->upper[i]), *get_mpz (as->lower[i]));
860 : 1446 : mpz_add_ui (extent, extent, 1);
861 : : }
862 : : else
863 : 1 : mpz_set_ui (extent, 0);
864 : :
865 : 1447 : if (mpz_sgn (extent) < 0)
866 : 0 : mpz_set_ui (extent, 0);
867 : :
868 : 1447 : mpz_mul (multiplier, multiplier, extent);
869 : : }
870 : :
871 : 1437 : i = mpz_get_ui (offset);
872 : :
873 : 1437 : mpz_clear (multiplier);
874 : 1437 : mpz_clear (offset);
875 : 1437 : mpz_clear (extent);
876 : 1437 : mpz_clear (n);
877 : :
878 : 1437 : return i;
879 : : }
880 : :
881 : :
882 : : /* Given a single element of an equivalence list, figure out the offset
883 : : from the base symbol. For simple variables or full arrays, this is
884 : : simply zero. For an array element we have to calculate the array
885 : : element number and multiply by the element size. For a substring we
886 : : have to calculate the further reference. */
887 : :
888 : : static HOST_WIDE_INT
889 : 3156 : calculate_offset (gfc_expr *e)
890 : : {
891 : 3156 : HOST_WIDE_INT n, element_size, offset;
892 : 3156 : gfc_typespec *element_type;
893 : 3156 : gfc_ref *reference;
894 : :
895 : 3156 : offset = 0;
896 : 3156 : element_type = &e->symtree->n.sym->ts;
897 : :
898 : 5365 : for (reference = e->ref; reference; reference = reference->next)
899 : 2209 : switch (reference->type)
900 : : {
901 : 1870 : case REF_ARRAY:
902 : 1870 : switch (reference->u.ar.type)
903 : : {
904 : : case AR_FULL:
905 : : break;
906 : :
907 : 1437 : case AR_ELEMENT:
908 : 1437 : n = element_number (&reference->u.ar);
909 : 1437 : if (element_type->type == BT_CHARACTER)
910 : 221 : gfc_conv_const_charlen (element_type->u.cl);
911 : 1437 : element_size =
912 : 1437 : int_size_in_bytes (gfc_typenode_for_spec (element_type));
913 : 1437 : offset += n * element_size;
914 : 1437 : break;
915 : :
916 : 0 : default:
917 : 0 : gfc_error ("Bad array reference at %L", &e->where);
918 : : }
919 : : break;
920 : 339 : case REF_SUBSTRING:
921 : 339 : if (reference->u.ss.start != NULL)
922 : 339 : offset += mpz_get_ui (*get_mpz (reference->u.ss.start)) - 1;
923 : : break;
924 : 0 : default:
925 : 0 : gfc_error ("Illegal reference type at %L as EQUIVALENCE object",
926 : : &e->where);
927 : : }
928 : 3156 : return offset;
929 : : }
930 : :
931 : :
932 : : /* Add a new segment_info structure to the current segment. eq1 is already
933 : : in the list, eq2 is not. */
934 : :
935 : : static void
936 : 1576 : new_condition (segment_info *v, gfc_equiv *eq1, gfc_equiv *eq2)
937 : : {
938 : 1576 : HOST_WIDE_INT offset1, offset2;
939 : 1576 : segment_info *a;
940 : :
941 : 1576 : offset1 = calculate_offset (eq1->expr);
942 : 1576 : offset2 = calculate_offset (eq2->expr);
943 : :
944 : 3152 : a = get_segment_info (eq2->expr->symtree->n.sym,
945 : 1576 : v->offset + offset1 - offset2);
946 : :
947 : 1576 : current_segment = add_segments (current_segment, a);
948 : 1576 : }
949 : :
950 : :
951 : : /* Given two equivalence structures that are both already in the list, make
952 : : sure that this new condition is not violated, generating an error if it
953 : : is. */
954 : :
955 : : static void
956 : 2 : confirm_condition (segment_info *s1, gfc_equiv *eq1, segment_info *s2,
957 : : gfc_equiv *eq2)
958 : : {
959 : 2 : HOST_WIDE_INT offset1, offset2;
960 : :
961 : 2 : offset1 = calculate_offset (eq1->expr);
962 : 2 : offset2 = calculate_offset (eq2->expr);
963 : :
964 : 2 : if (s1->offset + offset1 != s2->offset + offset2)
965 : 2 : gfc_error ("Inconsistent equivalence rules involving %qs at %L and "
966 : 2 : "%qs at %L", s1->sym->name, &s1->sym->declared_at,
967 : 2 : s2->sym->name, &s2->sym->declared_at);
968 : 2 : }
969 : :
970 : :
971 : : /* Process a new equivalence condition. eq1 is know to be in segment f.
972 : : If eq2 is also present then confirm that the condition holds.
973 : : Otherwise add a new variable to the segment list. */
974 : :
975 : : static void
976 : 1578 : add_condition (segment_info *f, gfc_equiv *eq1, gfc_equiv *eq2)
977 : : {
978 : 1578 : segment_info *n;
979 : :
980 : 1578 : n = find_segment_info (eq2->expr->symtree->n.sym);
981 : :
982 : 1578 : if (n == NULL)
983 : 1576 : new_condition (f, eq1, eq2);
984 : : else
985 : 2 : confirm_condition (f, eq1, n, eq2);
986 : 1578 : }
987 : :
988 : : static void
989 : 44810 : accumulate_equivalence_attributes (symbol_attribute *dummy_symbol, gfc_equiv *e)
990 : : {
991 : 44810 : symbol_attribute attr = e->expr->symtree->n.sym->attr;
992 : :
993 : 44810 : dummy_symbol->dummy |= attr.dummy;
994 : 44810 : dummy_symbol->pointer |= attr.pointer;
995 : 44810 : dummy_symbol->target |= attr.target;
996 : 44810 : dummy_symbol->external |= attr.external;
997 : 44810 : dummy_symbol->intrinsic |= attr.intrinsic;
998 : 44810 : dummy_symbol->allocatable |= attr.allocatable;
999 : 44810 : dummy_symbol->elemental |= attr.elemental;
1000 : 44810 : dummy_symbol->recursive |= attr.recursive;
1001 : 44810 : dummy_symbol->in_common |= attr.in_common;
1002 : 44810 : dummy_symbol->result |= attr.result;
1003 : 44810 : dummy_symbol->in_namelist |= attr.in_namelist;
1004 : 44810 : dummy_symbol->optional |= attr.optional;
1005 : 44810 : dummy_symbol->entry |= attr.entry;
1006 : 44810 : dummy_symbol->function |= attr.function;
1007 : 44810 : dummy_symbol->subroutine |= attr.subroutine;
1008 : 44810 : dummy_symbol->dimension |= attr.dimension;
1009 : 44810 : dummy_symbol->in_equivalence |= attr.in_equivalence;
1010 : 44810 : dummy_symbol->use_assoc |= attr.use_assoc;
1011 : 44810 : dummy_symbol->cray_pointer |= attr.cray_pointer;
1012 : 44810 : dummy_symbol->cray_pointee |= attr.cray_pointee;
1013 : 44810 : dummy_symbol->data |= attr.data;
1014 : 44810 : dummy_symbol->value |= attr.value;
1015 : 44810 : dummy_symbol->volatile_ |= attr.volatile_;
1016 : 44810 : dummy_symbol->is_protected |= attr.is_protected;
1017 : 44810 : dummy_symbol->is_bind_c |= attr.is_bind_c;
1018 : 44810 : dummy_symbol->procedure |= attr.procedure;
1019 : 44810 : dummy_symbol->proc_pointer |= attr.proc_pointer;
1020 : 44810 : dummy_symbol->abstract |= attr.abstract;
1021 : 44810 : dummy_symbol->asynchronous |= attr.asynchronous;
1022 : 44810 : dummy_symbol->codimension |= attr.codimension;
1023 : 44810 : dummy_symbol->contiguous |= attr.contiguous;
1024 : 44810 : dummy_symbol->generic |= attr.generic;
1025 : 44810 : dummy_symbol->automatic |= attr.automatic;
1026 : 44810 : dummy_symbol->threadprivate |= attr.threadprivate;
1027 : 44810 : dummy_symbol->omp_declare_target |= attr.omp_declare_target;
1028 : 44810 : dummy_symbol->omp_declare_target_link |= attr.omp_declare_target_link;
1029 : 44810 : dummy_symbol->oacc_declare_copyin |= attr.oacc_declare_copyin;
1030 : 44810 : dummy_symbol->oacc_declare_create |= attr.oacc_declare_create;
1031 : 44810 : dummy_symbol->oacc_declare_deviceptr |= attr.oacc_declare_deviceptr;
1032 : 44810 : dummy_symbol->oacc_declare_device_resident
1033 : 44810 : |= attr.oacc_declare_device_resident;
1034 : :
1035 : : /* Not strictly correct, but probably close enough. */
1036 : 44810 : if (attr.save > dummy_symbol->save)
1037 : 696 : dummy_symbol->save = attr.save;
1038 : 44810 : if (attr.access > dummy_symbol->access)
1039 : 4 : dummy_symbol->access = attr.access;
1040 : 44810 : }
1041 : :
1042 : : /* Given a segment element, search through the equivalence lists for unused
1043 : : conditions that involve the symbol. Add these rules to the segment. */
1044 : :
1045 : : static bool
1046 : 8212 : find_equivalence (segment_info *n)
1047 : : {
1048 : 8212 : gfc_equiv *e1, *e2, *eq;
1049 : 8212 : bool found;
1050 : :
1051 : 8212 : found = false;
1052 : :
1053 : 31159 : for (e1 = n->sym->ns->equiv; e1; e1 = e1->next)
1054 : : {
1055 : 22947 : eq = NULL;
1056 : :
1057 : : /* Search the equivalence list, including the root (first) element
1058 : : for the symbol that owns the segment. */
1059 : 22947 : symbol_attribute dummy_symbol;
1060 : 22947 : memset (&dummy_symbol, 0, sizeof (dummy_symbol));
1061 : 66226 : for (e2 = e1; e2; e2 = e2->eq)
1062 : : {
1063 : 44810 : accumulate_equivalence_attributes (&dummy_symbol, e2);
1064 : 44810 : if (!e2->used && e2->expr->symtree->n.sym == n->sym)
1065 : : {
1066 : : eq = e2;
1067 : : break;
1068 : : }
1069 : : }
1070 : :
1071 : 22947 : gfc_check_conflict (&dummy_symbol, e1->expr->symtree->name, &e1->expr->where);
1072 : :
1073 : : /* Go to the next root element. */
1074 : 22947 : if (eq == NULL)
1075 : 21416 : continue;
1076 : :
1077 : 1531 : eq->used = 1;
1078 : :
1079 : : /* Now traverse the equivalence list matching the offsets. */
1080 : 4640 : for (e2 = e1; e2; e2 = e2->eq)
1081 : : {
1082 : 3109 : if (!e2->used && e2 != eq)
1083 : : {
1084 : 1578 : add_condition (n, eq, e2);
1085 : 1578 : e2->used = 1;
1086 : 1578 : found = true;
1087 : : }
1088 : : }
1089 : : }
1090 : 8212 : return found;
1091 : : }
1092 : :
1093 : :
1094 : : /* Add all symbols equivalenced within a segment. We need to scan the
1095 : : segment list multiple times to include indirect equivalences. Since
1096 : : a new segment_info can inserted at the beginning of the segment list,
1097 : : depending on its offset, we have to force a final pass through the
1098 : : loop by demanding that completion sees a pass with no matches; i.e.,
1099 : : all symbols with equiv_built set and no new equivalences found. */
1100 : :
1101 : : static void
1102 : 6648 : add_equivalences (bool *saw_equiv)
1103 : : {
1104 : 6648 : segment_info *f;
1105 : 6648 : bool more = true;
1106 : :
1107 : 14467 : while (more)
1108 : : {
1109 : 7819 : more = false;
1110 : 17937 : for (f = current_segment; f; f = f->next)
1111 : : {
1112 : 10118 : if (!f->sym->equiv_built)
1113 : : {
1114 : 8212 : f->sym->equiv_built = 1;
1115 : 8212 : bool seen_one = find_equivalence (f);
1116 : 8212 : if (seen_one)
1117 : : {
1118 : 1178 : *saw_equiv = true;
1119 : 1178 : more = true;
1120 : : }
1121 : : }
1122 : : }
1123 : : }
1124 : :
1125 : : /* Add a copy of this segment list to the namespace. */
1126 : 6648 : copy_equiv_list_to_ns (current_segment);
1127 : 6648 : }
1128 : :
1129 : :
1130 : : /* Returns the offset necessary to properly align the current equivalence.
1131 : : Sets *palign to the required alignment. */
1132 : :
1133 : : static HOST_WIDE_INT
1134 : 6630 : align_segment (unsigned HOST_WIDE_INT *palign)
1135 : : {
1136 : 6630 : segment_info *s;
1137 : 6630 : unsigned HOST_WIDE_INT offset;
1138 : 6630 : unsigned HOST_WIDE_INT max_align;
1139 : 6630 : unsigned HOST_WIDE_INT this_align;
1140 : 6630 : unsigned HOST_WIDE_INT this_offset;
1141 : :
1142 : 6630 : max_align = 1;
1143 : 6630 : offset = 0;
1144 : 14836 : for (s = current_segment; s; s = s->next)
1145 : : {
1146 : 8206 : this_align = TYPE_ALIGN_UNIT (s->field);
1147 : 8206 : if (s->offset & (this_align - 1))
1148 : : {
1149 : : /* Field is misaligned. */
1150 : 128 : this_offset = this_align - ((s->offset + offset) & (this_align - 1));
1151 : 128 : if (this_offset & (max_align - 1))
1152 : : {
1153 : : /* Aligning this field would misalign a previous field. */
1154 : 0 : gfc_error ("The equivalence set for variable %qs "
1155 : : "declared at %L violates alignment requirements",
1156 : 0 : s->sym->name, &s->sym->declared_at);
1157 : : }
1158 : 128 : offset += this_offset;
1159 : : }
1160 : 8206 : max_align = this_align;
1161 : : }
1162 : 6630 : if (palign)
1163 : 6630 : *palign = max_align;
1164 : 6630 : return offset;
1165 : : }
1166 : :
1167 : :
1168 : : /* Adjust segment offsets by the given amount. */
1169 : :
1170 : : static void
1171 : 6648 : apply_segment_offset (segment_info *s, HOST_WIDE_INT offset)
1172 : : {
1173 : 14872 : for (; s; s = s->next)
1174 : 8224 : s->offset += offset;
1175 : 0 : }
1176 : :
1177 : :
1178 : : /* Lay out a symbol in a common block. If the symbol has already been seen
1179 : : then check the location is consistent. Otherwise create segments
1180 : : for that symbol and all the symbols equivalenced with it. */
1181 : :
1182 : : /* Translate a single common block. */
1183 : :
1184 : : static void
1185 : 2004 : translate_common (gfc_common_head *common, gfc_symbol *var_list)
1186 : : {
1187 : 2004 : gfc_symbol *sym;
1188 : 2004 : segment_info *s;
1189 : 2004 : segment_info *common_segment;
1190 : 2004 : HOST_WIDE_INT offset;
1191 : 2004 : HOST_WIDE_INT current_offset;
1192 : 2004 : unsigned HOST_WIDE_INT align;
1193 : 2004 : bool saw_equiv;
1194 : :
1195 : 2004 : common_segment = NULL;
1196 : 2004 : offset = 0;
1197 : 2004 : current_offset = 0;
1198 : 2004 : align = 1;
1199 : 2004 : saw_equiv = false;
1200 : :
1201 : : /* Add symbols to the segment. */
1202 : 7856 : for (sym = var_list; sym; sym = sym->common_next)
1203 : : {
1204 : 5852 : current_segment = common_segment;
1205 : 5852 : s = find_segment_info (sym);
1206 : :
1207 : : /* Symbol has already been added via an equivalence. Multiple
1208 : : use associations of the same common block result in equiv_built
1209 : : being set but no information about the symbol in the segment. */
1210 : 5852 : if (s && sym->equiv_built)
1211 : : {
1212 : : /* Ensure the current location is properly aligned. */
1213 : 7 : align = TYPE_ALIGN_UNIT (s->field);
1214 : 7 : current_offset = (current_offset + align - 1) &~ (align - 1);
1215 : :
1216 : : /* Verify that it ended up where we expect it. */
1217 : 7 : if (s->offset != current_offset)
1218 : : {
1219 : 1 : gfc_error ("Equivalence for %qs does not match ordering of "
1220 : : "COMMON %qs at %L", sym->name,
1221 : 1 : common->name, &common->where);
1222 : : }
1223 : : }
1224 : : else
1225 : : {
1226 : : /* A symbol we haven't seen before. */
1227 : 5845 : s = current_segment = get_segment_info (sym, current_offset);
1228 : :
1229 : : /* Add all objects directly or indirectly equivalenced with this
1230 : : symbol. */
1231 : 5845 : add_equivalences (&saw_equiv);
1232 : :
1233 : 5845 : if (current_segment->offset < 0)
1234 : 0 : gfc_error ("The equivalence set for %qs cause an invalid "
1235 : : "extension to COMMON %qs at %L", sym->name,
1236 : 0 : common->name, &common->where);
1237 : :
1238 : 5845 : if (flag_align_commons)
1239 : 5827 : offset = align_segment (&align);
1240 : :
1241 : 5845 : if (offset)
1242 : : {
1243 : : /* The required offset conflicts with previous alignment
1244 : : requirements. Insert padding immediately before this
1245 : : segment. */
1246 : 37 : if (warn_align_commons)
1247 : : {
1248 : 35 : if (strcmp (common->name, BLANK_COMMON_NAME))
1249 : 23 : gfc_warning (OPT_Walign_commons,
1250 : : "Padding of %d bytes required before %qs in "
1251 : : "COMMON %qs at %L; reorder elements or use "
1252 : : "%<-fno-align-commons%>", (int)offset,
1253 : 23 : s->sym->name, common->name, &common->where);
1254 : : else
1255 : 12 : gfc_warning (OPT_Walign_commons,
1256 : : "Padding of %d bytes required before %qs in "
1257 : : "COMMON at %L; reorder elements or use "
1258 : : "%<-fno-align-commons%>", (int)offset,
1259 : 12 : s->sym->name, &common->where);
1260 : : }
1261 : : }
1262 : :
1263 : : /* Apply the offset to the new segments. */
1264 : 5845 : apply_segment_offset (current_segment, offset);
1265 : 5845 : current_offset += offset;
1266 : :
1267 : : /* Add the new segments to the common block. */
1268 : 5845 : common_segment = add_segments (common_segment, current_segment);
1269 : : }
1270 : :
1271 : : /* The offset of the next common variable. */
1272 : 5852 : current_offset += s->length;
1273 : : }
1274 : :
1275 : 2004 : if (common_segment == NULL)
1276 : : {
1277 : 0 : gfc_error ("COMMON %qs at %L does not exist",
1278 : 0 : common->name, &common->where);
1279 : 0 : return;
1280 : : }
1281 : :
1282 : 2004 : if (common_segment->offset != 0 && warn_align_commons)
1283 : : {
1284 : 0 : if (strcmp (common->name, BLANK_COMMON_NAME))
1285 : 0 : gfc_warning (OPT_Walign_commons,
1286 : : "COMMON %qs at %L requires %d bytes of padding; "
1287 : : "reorder elements or use %<-fno-align-commons%>",
1288 : : common->name, &common->where, (int)common_segment->offset);
1289 : : else
1290 : 0 : gfc_warning (OPT_Walign_commons,
1291 : : "COMMON at %L requires %d bytes of padding; "
1292 : : "reorder elements or use %<-fno-align-commons%>",
1293 : : &common->where, (int)common_segment->offset);
1294 : : }
1295 : :
1296 : 2004 : create_common (common, common_segment, saw_equiv);
1297 : : }
1298 : :
1299 : :
1300 : : /* Create a new block for each merged equivalence list. */
1301 : :
1302 : : static void
1303 : 81531 : finish_equivalences (gfc_namespace *ns)
1304 : : {
1305 : 81531 : gfc_equiv *z, *y;
1306 : 81531 : gfc_symbol *sym;
1307 : 81531 : gfc_common_head * c;
1308 : 81531 : HOST_WIDE_INT offset;
1309 : 81531 : unsigned HOST_WIDE_INT align;
1310 : 81531 : bool dummy;
1311 : :
1312 : 83062 : for (z = ns->equiv; z; z = z->next)
1313 : 2289 : for (y = z->eq; y; y = y->eq)
1314 : : {
1315 : 1561 : if (y->used)
1316 : 758 : continue;
1317 : 803 : sym = z->expr->symtree->n.sym;
1318 : 803 : current_segment = get_segment_info (sym, 0);
1319 : :
1320 : : /* All objects directly or indirectly equivalenced with this
1321 : : symbol. */
1322 : 803 : add_equivalences (&dummy);
1323 : :
1324 : : /* Align the block. */
1325 : 803 : offset = align_segment (&align);
1326 : :
1327 : : /* Ensure all offsets are positive. */
1328 : 803 : offset -= current_segment->offset & ~(align - 1);
1329 : :
1330 : 803 : apply_segment_offset (current_segment, offset);
1331 : :
1332 : : /* Create the decl. If this is a module equivalence, it has a
1333 : : unique name, pointed to by z->module. This is written to a
1334 : : gfc_common_header to push create_common into using
1335 : : build_common_decl, so that the equivalence appears as an
1336 : : external symbol. Otherwise, a local declaration is built using
1337 : : build_equiv_decl. */
1338 : 803 : if (z->module)
1339 : : {
1340 : 105 : c = gfc_get_common_head ();
1341 : : /* We've lost the real location, so use the location of the
1342 : : enclosing procedure. If we're in a BLOCK DATA block, then
1343 : : use the location in the sym_root. */
1344 : 105 : if (ns->proc_name)
1345 : 104 : c->where = ns->proc_name->declared_at;
1346 : 1 : else if (ns->is_block_data)
1347 : 1 : c->where = ns->sym_root->n.sym->declared_at;
1348 : :
1349 : 105 : size_t len = strlen (z->module);
1350 : 105 : gcc_assert (len < sizeof (c->name));
1351 : 105 : memcpy (c->name, z->module, len);
1352 : 105 : c->name[len] = '\0';
1353 : : }
1354 : : else
1355 : : c = NULL;
1356 : :
1357 : 803 : create_common (c, current_segment, true);
1358 : 803 : break;
1359 : : }
1360 : 81531 : }
1361 : :
1362 : :
1363 : : /* Work function for translating a named common block. */
1364 : :
1365 : : static void
1366 : 1798 : named_common (gfc_symtree *st)
1367 : : {
1368 : 1798 : translate_common (st->n.common, st->n.common->head);
1369 : 1798 : }
1370 : :
1371 : :
1372 : : /* Translate the common blocks in a namespace. Unlike other variables,
1373 : : these have to be created before code, because the backend_decl depends
1374 : : on the rest of the common block. */
1375 : :
1376 : : void
1377 : 81531 : gfc_trans_common (gfc_namespace *ns)
1378 : : {
1379 : 81531 : gfc_common_head *c;
1380 : :
1381 : : /* Translate the blank common block. */
1382 : 81531 : if (ns->blank_common.head != NULL)
1383 : : {
1384 : 206 : c = gfc_get_common_head ();
1385 : 206 : c->where = ns->blank_common.head->common_head->where;
1386 : 206 : strcpy (c->name, BLANK_COMMON_NAME);
1387 : 206 : translate_common (c, ns->blank_common.head);
1388 : : }
1389 : :
1390 : : /* Translate all named common blocks. */
1391 : 81531 : gfc_traverse_symtree (ns->common_root, named_common);
1392 : :
1393 : : /* Translate local equivalence. */
1394 : 81531 : finish_equivalences (ns);
1395 : :
1396 : : /* Commit the newly created symbols for common blocks and module
1397 : : equivalences. */
1398 : 81531 : gfc_commit_symbols ();
1399 : 81531 : }
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