1 /* Common block and equivalence list handling
2 Copyright (C) 2000-2020 Free Software Foundation, Inc.
3 Contributed by Canqun Yang <canqun@nudt.edu.cn>
5 This file is part of GCC.
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
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
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/>. */
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.
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.
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.
32 So if two variables are equivalenced, they just point to a common
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.
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
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.
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
66 EQUIVALENCE(B(2), C(3))
68 B + 2*size of B's elements = C + 3*size of C's elements.
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
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.
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.
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. */
98 #include "coretypes.h"
101 #include "gfortran.h"
103 #include "stringpool.h"
104 #include "fold-const.h"
105 #include "stor-layout.h"
107 #include "trans-types.h"
108 #include "trans-const.h"
109 #include "target-memory.h"
112 /* Holds a single variable in an equivalence set. */
113 typedef struct segment_info
116 HOST_WIDE_INT offset
;
117 HOST_WIDE_INT length
;
118 /* This will contain the field type until the field is created. */
120 struct segment_info
*next
;
123 static segment_info
* current_segment
;
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
;
130 /* Make a segment_info based on a symbol. */
132 static segment_info
*
133 get_segment_info (gfc_symbol
* sym
, HOST_WIDE_INT offset
)
137 /* Make sure we've got the character length. */
138 if (sym
->ts
.type
== BT_CHARACTER
)
139 gfc_conv_const_charlen (sym
->ts
.u
.cl
);
141 /* Create the segment_info and fill it in. */
142 s
= XCNEW (segment_info
);
144 /* We will use this type when building the segment aggregate type. */
145 s
->field
= gfc_sym_type (sym
);
146 s
->length
= int_size_in_bytes (s
->field
);
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. */
158 copy_equiv_list_to_ns (segment_info
*c
)
164 l
= XCNEW (gfc_equiv_list
);
166 l
->next
= c
->sym
->ns
->equiv_lists
;
167 c
->sym
->ns
->equiv_lists
= l
;
169 for (f
= c
; f
; f
= f
->next
)
171 s
= XCNEW (gfc_equiv_info
);
175 s
->offset
= f
->offset
;
176 s
->length
= f
->length
;
181 /* Add combine segment V and segment LIST. */
183 static segment_info
*
184 add_segments (segment_info
*list
, segment_info
*v
)
195 /* Find the location of the new element. */
198 if (v
->offset
< s
->offset
)
200 if (v
->offset
== s
->offset
201 && v
->length
<= s
->length
)
208 /* Insert the new element in between p and s. */
224 /* Construct mangled common block name from symbol name. */
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).
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. */
242 gfc_sym_mangled_common_id (gfc_common_head
*com
)
245 /* Provide sufficient space to hold "symbol.symbol.eq.1234567890__". */
246 char mangled_name
[2*GFC_MAX_MANGLED_SYMBOL_LEN
+ 1 + 16 + 1];
247 char name
[sizeof (mangled_name
) - 2];
249 /* Get the name out of the common block pointer. */
250 size_t len
= strlen (com
->name
);
251 gcc_assert (len
< sizeof (name
));
252 strcpy (name
, com
->name
);
254 /* If we're suppose to do a bind(c). */
255 if (com
->is_bind_c
== 1 && com
->binding_label
)
256 return get_identifier (com
->binding_label
);
258 if (strcmp (name
, BLANK_COMMON_NAME
) == 0)
259 return get_identifier (name
);
261 if (flag_underscoring
)
263 has_underscore
= strchr (name
, '_') != 0;
264 if (flag_second_underscore
&& has_underscore
)
265 snprintf (mangled_name
, sizeof mangled_name
, "%s__", name
);
267 snprintf (mangled_name
, sizeof mangled_name
, "%s_", name
);
269 return get_identifier (mangled_name
);
272 return get_identifier (name
);
276 /* Build a field declaration for a common variable or a local equivalence
280 build_field (segment_info
*h
, tree union_type
, record_layout_info rli
)
284 HOST_WIDE_INT offset
= h
->offset
;
285 unsigned HOST_WIDE_INT desired_align
, known_align
;
287 name
= get_identifier (h
->sym
->name
);
288 field
= build_decl (gfc_get_location (&h
->sym
->declared_at
),
289 FIELD_DECL
, name
, h
->field
);
290 known_align
= (offset
& -offset
) * BITS_PER_UNIT
;
291 if (known_align
== 0 || known_align
> BIGGEST_ALIGNMENT
)
292 known_align
= BIGGEST_ALIGNMENT
;
294 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
295 if (desired_align
> known_align
)
296 DECL_PACKED (field
) = 1;
298 DECL_FIELD_CONTEXT (field
) = union_type
;
299 DECL_FIELD_OFFSET (field
) = size_int (offset
);
300 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
301 SET_DECL_OFFSET_ALIGN (field
, known_align
);
303 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 if (h
->sym
->attr
.assign
)
315 gfc_allocate_lang_decl (field
);
316 GFC_DECL_ASSIGN (field
) = 1;
317 len
= gfc_create_var_np (gfc_charlen_type_node
,h
->sym
->name
);
318 addr
= gfc_create_var_np (pvoid_type_node
, h
->sym
->name
);
319 TREE_STATIC (len
) = 1;
320 TREE_STATIC (addr
) = 1;
321 DECL_INITIAL (len
) = build_int_cst (gfc_charlen_type_node
, -2);
322 gfc_set_decl_location (len
, &h
->sym
->declared_at
);
323 gfc_set_decl_location (addr
, &h
->sym
->declared_at
);
324 GFC_DECL_STRING_LEN (field
) = pushdecl_top_level (len
);
325 GFC_DECL_ASSIGN_ADDR (field
) = pushdecl_top_level (addr
);
328 /* If this field is volatile, mark it. */
329 if (h
->sym
->attr
.volatile_
)
332 TREE_THIS_VOLATILE (field
) = 1;
333 TREE_SIDE_EFFECTS (field
) = 1;
334 new_type
= build_qualified_type (TREE_TYPE (field
), TYPE_QUAL_VOLATILE
);
335 TREE_TYPE (field
) = new_type
;
342 /* Get storage for local equivalence. */
345 build_equiv_decl (tree union_type
, bool is_init
, bool is_saved
, bool is_auto
)
349 static int serial
= 0;
353 decl
= gfc_create_var (union_type
, "equiv");
354 TREE_STATIC (decl
) = 1;
355 GFC_DECL_COMMON_OR_EQUIV (decl
) = 1;
359 snprintf (name
, sizeof (name
), "equiv.%d", serial
++);
360 decl
= build_decl (input_location
,
361 VAR_DECL
, get_identifier (name
), union_type
);
362 DECL_ARTIFICIAL (decl
) = 1;
363 DECL_IGNORED_P (decl
) = 1;
365 if (!is_auto
&& (!gfc_can_put_var_on_stack (DECL_SIZE_UNIT (decl
))
367 TREE_STATIC (decl
) = 1;
369 TREE_ADDRESSABLE (decl
) = 1;
370 TREE_USED (decl
) = 1;
371 GFC_DECL_COMMON_OR_EQUIV (decl
) = 1;
373 /* The source location has been lost, and doesn't really matter.
374 We need to set it to something though. */
375 gfc_set_decl_location (decl
, &gfc_current_locus
);
377 gfc_add_decl_to_function (decl
);
383 /* Get storage for common block. */
386 build_common_decl (gfc_common_head
*com
, tree union_type
, bool is_init
)
388 tree decl
, identifier
;
390 identifier
= gfc_sym_mangled_common_id (com
);
391 decl
= gfc_map_of_all_commons
.count(identifier
)
392 ? gfc_map_of_all_commons
[identifier
] : NULL_TREE
;
394 /* Update the size of this common block as needed. */
395 if (decl
!= NULL_TREE
)
397 tree size
= TYPE_SIZE_UNIT (union_type
);
399 /* Named common blocks of the same name shall be of the same size
400 in all scoping units of a program in which they appear, but
401 blank common blocks may be of different sizes. */
402 if (!tree_int_cst_equal (DECL_SIZE_UNIT (decl
), size
)
403 && strcmp (com
->name
, BLANK_COMMON_NAME
))
404 gfc_warning (0, "Named COMMON block %qs at %L shall be of the "
405 "same size as elsewhere (%lu vs %lu bytes)", com
->name
,
407 (unsigned long) TREE_INT_CST_LOW (size
),
408 (unsigned long) TREE_INT_CST_LOW (DECL_SIZE_UNIT (decl
)));
410 if (tree_int_cst_lt (DECL_SIZE_UNIT (decl
), size
))
412 DECL_SIZE (decl
) = TYPE_SIZE (union_type
);
413 DECL_SIZE_UNIT (decl
) = size
;
414 SET_DECL_MODE (decl
, TYPE_MODE (union_type
));
415 TREE_TYPE (decl
) = union_type
;
416 layout_decl (decl
, 0);
420 /* If this common block has been declared in a previous program unit,
421 and either it is already initialized or there is no new initialization
422 for it, just return. */
423 if ((decl
!= NULL_TREE
) && (!is_init
|| DECL_INITIAL (decl
)))
426 /* If there is no backend_decl for the common block, build it. */
427 if (decl
== NULL_TREE
)
429 if (com
->is_bind_c
== 1 && com
->binding_label
)
430 decl
= build_decl (input_location
, VAR_DECL
, identifier
, union_type
);
433 decl
= build_decl (input_location
, VAR_DECL
, get_identifier (com
->name
),
435 gfc_set_decl_assembler_name (decl
, identifier
);
438 TREE_PUBLIC (decl
) = 1;
439 TREE_STATIC (decl
) = 1;
440 DECL_IGNORED_P (decl
) = 1;
442 SET_DECL_ALIGN (decl
, BIGGEST_ALIGNMENT
);
445 /* Do not set the alignment for bind(c) common blocks to
446 BIGGEST_ALIGNMENT because that won't match what C does. Also,
447 for common blocks with one element, the alignment must be
448 that of the field within the common block in order to match
450 tree field
= NULL_TREE
;
451 field
= TYPE_FIELDS (TREE_TYPE (decl
));
452 if (DECL_CHAIN (field
) == NULL_TREE
)
453 SET_DECL_ALIGN (decl
, TYPE_ALIGN (TREE_TYPE (field
)));
455 DECL_USER_ALIGN (decl
) = 0;
456 GFC_DECL_COMMON_OR_EQUIV (decl
) = 1;
458 gfc_set_decl_location (decl
, &com
->where
);
460 if (com
->threadprivate
)
461 set_decl_tls_model (decl
, decl_default_tls_model (decl
));
463 if (com
->omp_declare_target_link
)
464 DECL_ATTRIBUTES (decl
)
465 = tree_cons (get_identifier ("omp declare target link"),
466 NULL_TREE
, DECL_ATTRIBUTES (decl
));
467 else if (com
->omp_declare_target
)
468 DECL_ATTRIBUTES (decl
)
469 = tree_cons (get_identifier ("omp declare target"),
470 NULL_TREE
, DECL_ATTRIBUTES (decl
));
472 /* Place the back end declaration for this common block in
473 GLOBAL_BINDING_LEVEL. */
474 gfc_map_of_all_commons
[identifier
] = pushdecl_top_level (decl
);
477 /* Has no initial values. */
480 DECL_INITIAL (decl
) = NULL_TREE
;
481 DECL_COMMON (decl
) = 1;
482 DECL_DEFER_OUTPUT (decl
) = 1;
486 DECL_INITIAL (decl
) = error_mark_node
;
487 DECL_COMMON (decl
) = 0;
488 DECL_DEFER_OUTPUT (decl
) = 0;
494 /* Return a field that is the size of the union, if an equivalence has
495 overlapping initializers. Merge the initializers into a single
496 initializer for this new field, then free the old ones. */
499 get_init_field (segment_info
*head
, tree union_type
, tree
*field_init
,
500 record_layout_info rli
)
503 HOST_WIDE_INT length
= 0;
504 HOST_WIDE_INT offset
= 0;
505 unsigned HOST_WIDE_INT known_align
, desired_align
;
506 bool overlap
= false;
509 unsigned char *data
, *chk
;
510 vec
<constructor_elt
, va_gc
> *v
= NULL
;
512 tree type
= unsigned_char_type_node
;
515 /* Obtain the size of the union and check if there are any overlapping
517 for (s
= head
; s
; s
= s
->next
)
519 HOST_WIDE_INT slen
= s
->offset
+ s
->length
;
522 if (s
->offset
< offset
)
526 length
= length
< slen
? slen
: length
;
532 /* Now absorb all the initializer data into a single vector,
533 whilst checking for overlapping, unequal values. */
534 data
= XCNEWVEC (unsigned char, (size_t)length
);
535 chk
= XCNEWVEC (unsigned char, (size_t)length
);
537 /* TODO - change this when default initialization is implemented. */
538 memset (data
, '\0', (size_t)length
);
539 memset (chk
, '\0', (size_t)length
);
540 for (s
= head
; s
; s
= s
->next
)
544 if (s
->sym
->ns
->equiv
&& s
->sym
->ns
->equiv
->eq
)
545 loc
= &s
->sym
->ns
->equiv
->eq
->expr
->where
;
546 gfc_merge_initializers (s
->sym
->ts
, s
->sym
->value
, loc
,
552 for (i
= 0; i
< length
; i
++)
553 CONSTRUCTOR_APPEND_ELT (v
, NULL
, build_int_cst (type
, data
[i
]));
558 /* Build a char[length] array to hold the initializers. Much of what
559 follows is borrowed from build_field, above. */
561 tmp
= build_int_cst (gfc_array_index_type
, length
- 1);
562 tmp
= build_range_type (gfc_array_index_type
,
563 gfc_index_zero_node
, tmp
);
564 tmp
= build_array_type (type
, tmp
);
565 field
= build_decl (gfc_get_location (&gfc_current_locus
),
566 FIELD_DECL
, NULL_TREE
, tmp
);
568 known_align
= BIGGEST_ALIGNMENT
;
570 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
571 if (desired_align
> known_align
)
572 DECL_PACKED (field
) = 1;
574 DECL_FIELD_CONTEXT (field
) = union_type
;
575 DECL_FIELD_OFFSET (field
) = size_int (0);
576 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
577 SET_DECL_OFFSET_ALIGN (field
, known_align
);
579 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
,
580 size_binop (PLUS_EXPR
,
581 DECL_FIELD_OFFSET (field
),
582 DECL_SIZE_UNIT (field
)));
584 init
= build_constructor (TREE_TYPE (field
), v
);
585 TREE_CONSTANT (init
) = 1;
589 for (s
= head
; s
; s
= s
->next
)
591 if (s
->sym
->value
== NULL
)
594 gfc_free_expr (s
->sym
->value
);
595 s
->sym
->value
= NULL
;
602 /* Declare memory for the common block or local equivalence, and create
603 backend declarations for all of the elements. */
606 create_common (gfc_common_head
*com
, segment_info
*head
, bool saw_equiv
)
608 segment_info
*s
, *next_s
;
612 tree field_init
= NULL_TREE
;
613 record_layout_info rli
;
615 bool is_init
= false;
616 bool is_saved
= false;
617 bool is_auto
= false;
619 /* Declare the variables inside the common block.
620 If the current common block contains any equivalence object, then
621 make a UNION_TYPE node, otherwise RECORD_TYPE. This will let the
622 alias analyzer work well when there is no address overlapping for
623 common variables in the current common block. */
625 union_type
= make_node (UNION_TYPE
);
627 union_type
= make_node (RECORD_TYPE
);
629 rli
= start_record_layout (union_type
);
630 field_link
= &TYPE_FIELDS (union_type
);
632 /* Check for overlapping initializers and replace them with a single,
633 artificial field that contains all the data. */
635 field
= get_init_field (head
, union_type
, &field_init
, rli
);
639 if (field
!= NULL_TREE
)
643 field_link
= &DECL_CHAIN (field
);
646 for (s
= head
; s
; s
= s
->next
)
648 build_field (s
, union_type
, rli
);
650 /* Link the field into the type. */
651 *field_link
= s
->field
;
652 field_link
= &DECL_CHAIN (s
->field
);
654 /* Has initial value. */
658 /* Has SAVE attribute. */
659 if (s
->sym
->attr
.save
)
662 /* Has AUTOMATIC attribute. */
663 if (s
->sym
->attr
.automatic
)
667 finish_record_layout (rli
, true);
670 decl
= build_common_decl (com
, union_type
, is_init
);
672 decl
= build_equiv_decl (union_type
, is_init
, is_saved
, is_auto
);
677 vec
<constructor_elt
, va_gc
> *v
= NULL
;
679 if (field
!= NULL_TREE
&& field_init
!= NULL_TREE
)
680 CONSTRUCTOR_APPEND_ELT (v
, field
, field_init
);
682 for (s
= head
; s
; s
= s
->next
)
686 /* Add the initializer for this field. */
687 tmp
= gfc_conv_initializer (s
->sym
->value
, &s
->sym
->ts
,
688 TREE_TYPE (s
->field
),
689 s
->sym
->attr
.dimension
,
691 || s
->sym
->attr
.allocatable
, false);
693 CONSTRUCTOR_APPEND_ELT (v
, s
->field
, tmp
);
697 gcc_assert (!v
->is_empty ());
698 ctor
= build_constructor (union_type
, v
);
699 TREE_CONSTANT (ctor
) = 1;
700 TREE_STATIC (ctor
) = 1;
701 DECL_INITIAL (decl
) = ctor
;
706 unsigned HOST_WIDE_INT idx
;
707 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor
), idx
, field
, value
)
708 gcc_assert (TREE_CODE (field
) == FIELD_DECL
);
712 /* Build component reference for each variable. */
713 for (s
= head
; s
; s
= next_s
)
717 var_decl
= build_decl (gfc_get_location (&s
->sym
->declared_at
),
718 VAR_DECL
, DECL_NAME (s
->field
),
719 TREE_TYPE (s
->field
));
720 TREE_STATIC (var_decl
) = TREE_STATIC (decl
);
721 /* Mark the variable as used in order to avoid warnings about
723 TREE_USED (var_decl
) = 1;
724 if (s
->sym
->attr
.use_assoc
)
725 DECL_IGNORED_P (var_decl
) = 1;
726 if (s
->sym
->attr
.target
)
727 TREE_ADDRESSABLE (var_decl
) = 1;
728 /* Fake variables are not visible from other translation units. */
729 TREE_PUBLIC (var_decl
) = 0;
730 gfc_finish_decl_attrs (var_decl
, &s
->sym
->attr
);
732 /* To preserve identifier names in COMMON, chain to procedure
733 scope unless at top level in a module definition. */
735 && s
->sym
->ns
->proc_name
736 && s
->sym
->ns
->proc_name
->attr
.flavor
== FL_MODULE
)
737 var_decl
= pushdecl_top_level (var_decl
);
739 gfc_add_decl_to_function (var_decl
);
741 SET_DECL_VALUE_EXPR (var_decl
,
742 fold_build3_loc (input_location
, COMPONENT_REF
,
743 TREE_TYPE (s
->field
),
744 decl
, s
->field
, NULL_TREE
));
745 DECL_HAS_VALUE_EXPR_P (var_decl
) = 1;
746 GFC_DECL_COMMON_OR_EQUIV (var_decl
) = 1;
748 if (s
->sym
->attr
.assign
)
750 gfc_allocate_lang_decl (var_decl
);
751 GFC_DECL_ASSIGN (var_decl
) = 1;
752 GFC_DECL_STRING_LEN (var_decl
) = GFC_DECL_STRING_LEN (s
->field
);
753 GFC_DECL_ASSIGN_ADDR (var_decl
) = GFC_DECL_ASSIGN_ADDR (s
->field
);
756 s
->sym
->backend_decl
= var_decl
;
764 /* Given a symbol, find it in the current segment list. Returns NULL if
767 static segment_info
*
768 find_segment_info (gfc_symbol
*symbol
)
772 for (n
= current_segment
; n
; n
= n
->next
)
774 if (n
->sym
== symbol
)
782 /* Given an expression node, make sure it is a constant integer and return
786 get_mpz (gfc_expr
*e
)
789 if (e
->expr_type
!= EXPR_CONSTANT
)
790 gfc_internal_error ("get_mpz(): Not an integer constant");
792 return &e
->value
.integer
;
796 /* Given an array specification and an array reference, figure out the
797 array element number (zero based). Bounds and elements are guaranteed
798 to be constants. If something goes wrong we generate an error and
802 element_number (gfc_array_ref
*ar
)
804 mpz_t multiplier
, offset
, extent
, n
;
806 HOST_WIDE_INT i
, rank
;
810 mpz_init_set_ui (multiplier
, 1);
811 mpz_init_set_ui (offset
, 0);
815 for (i
= 0; i
< rank
; i
++)
817 if (ar
->dimen_type
[i
] != DIMEN_ELEMENT
)
818 gfc_internal_error ("element_number(): Bad dimension type");
820 if (as
&& as
->lower
[i
])
821 mpz_sub (n
, *get_mpz (ar
->start
[i
]), *get_mpz (as
->lower
[i
]));
823 mpz_sub_ui (n
, *get_mpz (ar
->start
[i
]), 1);
825 mpz_mul (n
, n
, multiplier
);
826 mpz_add (offset
, offset
, n
);
828 if (as
&& as
->upper
[i
] && as
->lower
[i
])
830 mpz_sub (extent
, *get_mpz (as
->upper
[i
]), *get_mpz (as
->lower
[i
]));
831 mpz_add_ui (extent
, extent
, 1);
834 mpz_set_ui (extent
, 0);
836 if (mpz_sgn (extent
) < 0)
837 mpz_set_ui (extent
, 0);
839 mpz_mul (multiplier
, multiplier
, extent
);
842 i
= mpz_get_ui (offset
);
844 mpz_clear (multiplier
);
853 /* Given a single element of an equivalence list, figure out the offset
854 from the base symbol. For simple variables or full arrays, this is
855 simply zero. For an array element we have to calculate the array
856 element number and multiply by the element size. For a substring we
857 have to calculate the further reference. */
860 calculate_offset (gfc_expr
*e
)
862 HOST_WIDE_INT n
, element_size
, offset
;
863 gfc_typespec
*element_type
;
867 element_type
= &e
->symtree
->n
.sym
->ts
;
869 for (reference
= e
->ref
; reference
; reference
= reference
->next
)
870 switch (reference
->type
)
873 switch (reference
->u
.ar
.type
)
879 n
= element_number (&reference
->u
.ar
);
880 if (element_type
->type
== BT_CHARACTER
)
881 gfc_conv_const_charlen (element_type
->u
.cl
);
883 int_size_in_bytes (gfc_typenode_for_spec (element_type
));
884 offset
+= n
* element_size
;
888 gfc_error ("Bad array reference at %L", &e
->where
);
892 if (reference
->u
.ss
.start
!= NULL
)
893 offset
+= mpz_get_ui (*get_mpz (reference
->u
.ss
.start
)) - 1;
896 gfc_error ("Illegal reference type at %L as EQUIVALENCE object",
903 /* Add a new segment_info structure to the current segment. eq1 is already
904 in the list, eq2 is not. */
907 new_condition (segment_info
*v
, gfc_equiv
*eq1
, gfc_equiv
*eq2
)
909 HOST_WIDE_INT offset1
, offset2
;
912 offset1
= calculate_offset (eq1
->expr
);
913 offset2
= calculate_offset (eq2
->expr
);
915 a
= get_segment_info (eq2
->expr
->symtree
->n
.sym
,
916 v
->offset
+ offset1
- offset2
);
918 current_segment
= add_segments (current_segment
, a
);
922 /* Given two equivalence structures that are both already in the list, make
923 sure that this new condition is not violated, generating an error if it
927 confirm_condition (segment_info
*s1
, gfc_equiv
*eq1
, segment_info
*s2
,
930 HOST_WIDE_INT offset1
, offset2
;
932 offset1
= calculate_offset (eq1
->expr
);
933 offset2
= calculate_offset (eq2
->expr
);
935 if (s1
->offset
+ offset1
!= s2
->offset
+ offset2
)
936 gfc_error ("Inconsistent equivalence rules involving %qs at %L and "
937 "%qs at %L", s1
->sym
->name
, &s1
->sym
->declared_at
,
938 s2
->sym
->name
, &s2
->sym
->declared_at
);
942 /* Process a new equivalence condition. eq1 is know to be in segment f.
943 If eq2 is also present then confirm that the condition holds.
944 Otherwise add a new variable to the segment list. */
947 add_condition (segment_info
*f
, gfc_equiv
*eq1
, gfc_equiv
*eq2
)
951 n
= find_segment_info (eq2
->expr
->symtree
->n
.sym
);
954 new_condition (f
, eq1
, eq2
);
956 confirm_condition (f
, eq1
, n
, eq2
);
960 accumulate_equivalence_attributes (symbol_attribute
*dummy_symbol
, gfc_equiv
*e
)
962 symbol_attribute attr
= e
->expr
->symtree
->n
.sym
->attr
;
964 dummy_symbol
->dummy
|= attr
.dummy
;
965 dummy_symbol
->pointer
|= attr
.pointer
;
966 dummy_symbol
->target
|= attr
.target
;
967 dummy_symbol
->external
|= attr
.external
;
968 dummy_symbol
->intrinsic
|= attr
.intrinsic
;
969 dummy_symbol
->allocatable
|= attr
.allocatable
;
970 dummy_symbol
->elemental
|= attr
.elemental
;
971 dummy_symbol
->recursive
|= attr
.recursive
;
972 dummy_symbol
->in_common
|= attr
.in_common
;
973 dummy_symbol
->result
|= attr
.result
;
974 dummy_symbol
->in_namelist
|= attr
.in_namelist
;
975 dummy_symbol
->optional
|= attr
.optional
;
976 dummy_symbol
->entry
|= attr
.entry
;
977 dummy_symbol
->function
|= attr
.function
;
978 dummy_symbol
->subroutine
|= attr
.subroutine
;
979 dummy_symbol
->dimension
|= attr
.dimension
;
980 dummy_symbol
->in_equivalence
|= attr
.in_equivalence
;
981 dummy_symbol
->use_assoc
|= attr
.use_assoc
;
982 dummy_symbol
->cray_pointer
|= attr
.cray_pointer
;
983 dummy_symbol
->cray_pointee
|= attr
.cray_pointee
;
984 dummy_symbol
->data
|= attr
.data
;
985 dummy_symbol
->value
|= attr
.value
;
986 dummy_symbol
->volatile_
|= attr
.volatile_
;
987 dummy_symbol
->is_protected
|= attr
.is_protected
;
988 dummy_symbol
->is_bind_c
|= attr
.is_bind_c
;
989 dummy_symbol
->procedure
|= attr
.procedure
;
990 dummy_symbol
->proc_pointer
|= attr
.proc_pointer
;
991 dummy_symbol
->abstract
|= attr
.abstract
;
992 dummy_symbol
->asynchronous
|= attr
.asynchronous
;
993 dummy_symbol
->codimension
|= attr
.codimension
;
994 dummy_symbol
->contiguous
|= attr
.contiguous
;
995 dummy_symbol
->generic
|= attr
.generic
;
996 dummy_symbol
->automatic
|= attr
.automatic
;
997 dummy_symbol
->threadprivate
|= attr
.threadprivate
;
998 dummy_symbol
->omp_declare_target
|= attr
.omp_declare_target
;
999 dummy_symbol
->omp_declare_target_link
|= attr
.omp_declare_target_link
;
1000 dummy_symbol
->oacc_declare_copyin
|= attr
.oacc_declare_copyin
;
1001 dummy_symbol
->oacc_declare_create
|= attr
.oacc_declare_create
;
1002 dummy_symbol
->oacc_declare_deviceptr
|= attr
.oacc_declare_deviceptr
;
1003 dummy_symbol
->oacc_declare_device_resident
1004 |= attr
.oacc_declare_device_resident
;
1006 /* Not strictly correct, but probably close enough. */
1007 if (attr
.save
> dummy_symbol
->save
)
1008 dummy_symbol
->save
= attr
.save
;
1009 if (attr
.access
> dummy_symbol
->access
)
1010 dummy_symbol
->access
= attr
.access
;
1013 /* Given a segment element, search through the equivalence lists for unused
1014 conditions that involve the symbol. Add these rules to the segment. */
1017 find_equivalence (segment_info
*n
)
1019 gfc_equiv
*e1
, *e2
, *eq
;
1024 for (e1
= n
->sym
->ns
->equiv
; e1
; e1
= e1
->next
)
1028 /* Search the equivalence list, including the root (first) element
1029 for the symbol that owns the segment. */
1030 symbol_attribute dummy_symbol
;
1031 memset (&dummy_symbol
, 0, sizeof (dummy_symbol
));
1032 for (e2
= e1
; e2
; e2
= e2
->eq
)
1034 accumulate_equivalence_attributes (&dummy_symbol
, e2
);
1035 if (!e2
->used
&& e2
->expr
->symtree
->n
.sym
== n
->sym
)
1042 gfc_check_conflict (&dummy_symbol
, e1
->expr
->symtree
->name
, &e1
->expr
->where
);
1044 /* Go to the next root element. */
1050 /* Now traverse the equivalence list matching the offsets. */
1051 for (e2
= e1
; e2
; e2
= e2
->eq
)
1053 if (!e2
->used
&& e2
!= eq
)
1055 add_condition (n
, eq
, e2
);
1065 /* Add all symbols equivalenced within a segment. We need to scan the
1066 segment list multiple times to include indirect equivalences. Since
1067 a new segment_info can inserted at the beginning of the segment list,
1068 depending on its offset, we have to force a final pass through the
1069 loop by demanding that completion sees a pass with no matches; i.e.,
1070 all symbols with equiv_built set and no new equivalences found. */
1073 add_equivalences (bool *saw_equiv
)
1081 for (f
= current_segment
; f
; f
= f
->next
)
1083 if (!f
->sym
->equiv_built
)
1085 f
->sym
->equiv_built
= 1;
1086 bool seen_one
= find_equivalence (f
);
1096 /* Add a copy of this segment list to the namespace. */
1097 copy_equiv_list_to_ns (current_segment
);
1101 /* Returns the offset necessary to properly align the current equivalence.
1102 Sets *palign to the required alignment. */
1104 static HOST_WIDE_INT
1105 align_segment (unsigned HOST_WIDE_INT
*palign
)
1108 unsigned HOST_WIDE_INT offset
;
1109 unsigned HOST_WIDE_INT max_align
;
1110 unsigned HOST_WIDE_INT this_align
;
1111 unsigned HOST_WIDE_INT this_offset
;
1115 for (s
= current_segment
; s
; s
= s
->next
)
1117 this_align
= TYPE_ALIGN_UNIT (s
->field
);
1118 if (s
->offset
& (this_align
- 1))
1120 /* Field is misaligned. */
1121 this_offset
= this_align
- ((s
->offset
+ offset
) & (this_align
- 1));
1122 if (this_offset
& (max_align
- 1))
1124 /* Aligning this field would misalign a previous field. */
1125 gfc_error ("The equivalence set for variable %qs "
1126 "declared at %L violates alignment requirements",
1127 s
->sym
->name
, &s
->sym
->declared_at
);
1129 offset
+= this_offset
;
1131 max_align
= this_align
;
1134 *palign
= max_align
;
1139 /* Adjust segment offsets by the given amount. */
1142 apply_segment_offset (segment_info
*s
, HOST_WIDE_INT offset
)
1144 for (; s
; s
= s
->next
)
1145 s
->offset
+= offset
;
1149 /* Lay out a symbol in a common block. If the symbol has already been seen
1150 then check the location is consistent. Otherwise create segments
1151 for that symbol and all the symbols equivalenced with it. */
1153 /* Translate a single common block. */
1156 translate_common (gfc_common_head
*common
, gfc_symbol
*var_list
)
1160 segment_info
*common_segment
;
1161 HOST_WIDE_INT offset
;
1162 HOST_WIDE_INT current_offset
;
1163 unsigned HOST_WIDE_INT align
;
1166 common_segment
= NULL
;
1172 /* Add symbols to the segment. */
1173 for (sym
= var_list
; sym
; sym
= sym
->common_next
)
1175 current_segment
= common_segment
;
1176 s
= find_segment_info (sym
);
1178 /* Symbol has already been added via an equivalence. Multiple
1179 use associations of the same common block result in equiv_built
1180 being set but no information about the symbol in the segment. */
1181 if (s
&& sym
->equiv_built
)
1183 /* Ensure the current location is properly aligned. */
1184 align
= TYPE_ALIGN_UNIT (s
->field
);
1185 current_offset
= (current_offset
+ align
- 1) &~ (align
- 1);
1187 /* Verify that it ended up where we expect it. */
1188 if (s
->offset
!= current_offset
)
1190 gfc_error ("Equivalence for %qs does not match ordering of "
1191 "COMMON %qs at %L", sym
->name
,
1192 common
->name
, &common
->where
);
1197 /* A symbol we haven't seen before. */
1198 s
= current_segment
= get_segment_info (sym
, current_offset
);
1200 /* Add all objects directly or indirectly equivalenced with this
1202 add_equivalences (&saw_equiv
);
1204 if (current_segment
->offset
< 0)
1205 gfc_error ("The equivalence set for %qs cause an invalid "
1206 "extension to COMMON %qs at %L", sym
->name
,
1207 common
->name
, &common
->where
);
1209 if (flag_align_commons
)
1210 offset
= align_segment (&align
);
1214 /* The required offset conflicts with previous alignment
1215 requirements. Insert padding immediately before this
1217 if (warn_align_commons
)
1219 if (strcmp (common
->name
, BLANK_COMMON_NAME
))
1220 gfc_warning (OPT_Walign_commons
,
1221 "Padding of %d bytes required before %qs in "
1222 "COMMON %qs at %L; reorder elements or use "
1223 "%<-fno-align-commons%>", (int)offset
,
1224 s
->sym
->name
, common
->name
, &common
->where
);
1226 gfc_warning (OPT_Walign_commons
,
1227 "Padding of %d bytes required before %qs in "
1228 "COMMON at %L; reorder elements or use "
1229 "%<-fno-align-commons%>", (int)offset
,
1230 s
->sym
->name
, &common
->where
);
1234 /* Apply the offset to the new segments. */
1235 apply_segment_offset (current_segment
, offset
);
1236 current_offset
+= offset
;
1238 /* Add the new segments to the common block. */
1239 common_segment
= add_segments (common_segment
, current_segment
);
1242 /* The offset of the next common variable. */
1243 current_offset
+= s
->length
;
1246 if (common_segment
== NULL
)
1248 gfc_error ("COMMON %qs at %L does not exist",
1249 common
->name
, &common
->where
);
1253 if (common_segment
->offset
!= 0 && warn_align_commons
)
1255 if (strcmp (common
->name
, BLANK_COMMON_NAME
))
1256 gfc_warning (OPT_Walign_commons
,
1257 "COMMON %qs at %L requires %d bytes of padding; "
1258 "reorder elements or use %<-fno-align-commons%>",
1259 common
->name
, &common
->where
, (int)common_segment
->offset
);
1261 gfc_warning (OPT_Walign_commons
,
1262 "COMMON at %L requires %d bytes of padding; "
1263 "reorder elements or use %<-fno-align-commons%>",
1264 &common
->where
, (int)common_segment
->offset
);
1267 create_common (common
, common_segment
, saw_equiv
);
1271 /* Create a new block for each merged equivalence list. */
1274 finish_equivalences (gfc_namespace
*ns
)
1278 gfc_common_head
* c
;
1279 HOST_WIDE_INT offset
;
1280 unsigned HOST_WIDE_INT align
;
1283 for (z
= ns
->equiv
; z
; z
= z
->next
)
1284 for (y
= z
->eq
; y
; y
= y
->eq
)
1288 sym
= z
->expr
->symtree
->n
.sym
;
1289 current_segment
= get_segment_info (sym
, 0);
1291 /* All objects directly or indirectly equivalenced with this
1293 add_equivalences (&dummy
);
1295 /* Align the block. */
1296 offset
= align_segment (&align
);
1298 /* Ensure all offsets are positive. */
1299 offset
-= current_segment
->offset
& ~(align
- 1);
1301 apply_segment_offset (current_segment
, offset
);
1303 /* Create the decl. If this is a module equivalence, it has a
1304 unique name, pointed to by z->module. This is written to a
1305 gfc_common_header to push create_common into using
1306 build_common_decl, so that the equivalence appears as an
1307 external symbol. Otherwise, a local declaration is built using
1308 build_equiv_decl. */
1311 c
= gfc_get_common_head ();
1312 /* We've lost the real location, so use the location of the
1313 enclosing procedure. If we're in a BLOCK DATA block, then
1314 use the location in the sym_root. */
1316 c
->where
= ns
->proc_name
->declared_at
;
1317 else if (ns
->is_block_data
)
1318 c
->where
= ns
->sym_root
->n
.sym
->declared_at
;
1320 size_t len
= strlen (z
->module
);
1321 gcc_assert (len
< sizeof (c
->name
));
1322 memcpy (c
->name
, z
->module
, len
);
1323 c
->name
[len
] = '\0';
1328 create_common (c
, current_segment
, true);
1334 /* Work function for translating a named common block. */
1337 named_common (gfc_symtree
*st
)
1339 translate_common (st
->n
.common
, st
->n
.common
->head
);
1343 /* Translate the common blocks in a namespace. Unlike other variables,
1344 these have to be created before code, because the backend_decl depends
1345 on the rest of the common block. */
1348 gfc_trans_common (gfc_namespace
*ns
)
1352 /* Translate the blank common block. */
1353 if (ns
->blank_common
.head
!= NULL
)
1355 c
= gfc_get_common_head ();
1356 c
->where
= ns
->blank_common
.head
->common_head
->where
;
1357 strcpy (c
->name
, BLANK_COMMON_NAME
);
1358 translate_common (c
, ns
->blank_common
.head
);
1361 /* Translate all named common blocks. */
1362 gfc_traverse_symtree (ns
->common_root
, named_common
);
1364 /* Translate local equivalence. */
1365 finish_equivalences (ns
);
1367 /* Commit the newly created symbols for common blocks and module
1369 gfc_commit_symbols ();