1 /* Common block and equivalence list handling
2 Copyright (C) 2000-2015 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. */
100 #include "coretypes.h"
104 #include "fold-const.h"
105 #include "stringpool.h"
106 #include "stor-layout.h"
108 #include "gfortran.h"
110 #include "trans-types.h"
111 #include "trans-const.h"
112 #include "target-memory.h"
115 /* Holds a single variable in an equivalence set. */
116 typedef struct segment_info
119 HOST_WIDE_INT offset
;
120 HOST_WIDE_INT length
;
121 /* This will contain the field type until the field is created. */
123 struct segment_info
*next
;
126 static segment_info
* current_segment
;
128 /* Store decl of all common blocks in this translation unit; the first
129 tree is the identifier. */
130 static std::map
<tree
, tree
> gfc_map_of_all_commons
;
133 /* Make a segment_info based on a symbol. */
135 static segment_info
*
136 get_segment_info (gfc_symbol
* sym
, HOST_WIDE_INT offset
)
140 /* Make sure we've got the character length. */
141 if (sym
->ts
.type
== BT_CHARACTER
)
142 gfc_conv_const_charlen (sym
->ts
.u
.cl
);
144 /* Create the segment_info and fill it in. */
145 s
= XCNEW (segment_info
);
147 /* We will use this type when building the segment aggregate type. */
148 s
->field
= gfc_sym_type (sym
);
149 s
->length
= int_size_in_bytes (s
->field
);
156 /* Add a copy of a segment list to the namespace. This is specifically for
157 equivalence segments, so that dependency checking can be done on
158 equivalence group members. */
161 copy_equiv_list_to_ns (segment_info
*c
)
167 l
= XCNEW (gfc_equiv_list
);
169 l
->next
= c
->sym
->ns
->equiv_lists
;
170 c
->sym
->ns
->equiv_lists
= l
;
172 for (f
= c
; f
; f
= f
->next
)
174 s
= XCNEW (gfc_equiv_info
);
178 s
->offset
= f
->offset
;
179 s
->length
= f
->length
;
184 /* Add combine segment V and segment LIST. */
186 static segment_info
*
187 add_segments (segment_info
*list
, segment_info
*v
)
198 /* Find the location of the new element. */
201 if (v
->offset
< s
->offset
)
203 if (v
->offset
== s
->offset
204 && v
->length
<= s
->length
)
211 /* Insert the new element in between p and s. */
227 /* Construct mangled common block name from symbol name. */
229 /* We need the bind(c) flag to tell us how/if we should mangle the symbol
230 name. There are few calls to this function, so few places that this
231 would need to be added. At the moment, there is only one call, in
232 build_common_decl(). We can't attempt to look up the common block
233 because we may be building it for the first time and therefore, it won't
234 be in the common_root. We also need the binding label, if it's bind(c).
235 Therefore, send in the pointer to the common block, so whatever info we
236 have so far can be used. All of the necessary info should be available
237 in the gfc_common_head by now, so it should be accurate to test the
238 isBindC flag and use the binding label given if it is bind(c).
240 We may NOT know yet if it's bind(c) or not, but we can try at least.
241 Will have to figure out what to do later if it's labeled bind(c)
242 after this is called. */
245 gfc_sym_mangled_common_id (gfc_common_head
*com
)
248 char mangled_name
[GFC_MAX_MANGLED_SYMBOL_LEN
+ 1];
249 char name
[GFC_MAX_SYMBOL_LEN
+ 1];
251 /* Get the name out of the common block pointer. */
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 (h
->sym
->declared_at
.lb
->location
,
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
)
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 (!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 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 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 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
)
464 DECL_ATTRIBUTES (decl
)
465 = tree_cons (get_identifier ("omp declare target"),
466 NULL_TREE
, DECL_ATTRIBUTES (decl
));
468 /* Place the back end declaration for this common block in
469 GLOBAL_BINDING_LEVEL. */
470 gfc_map_of_all_commons
[identifier
] = pushdecl_top_level (decl
);
473 /* Has no initial values. */
476 DECL_INITIAL (decl
) = NULL_TREE
;
477 DECL_COMMON (decl
) = 1;
478 DECL_DEFER_OUTPUT (decl
) = 1;
482 DECL_INITIAL (decl
) = error_mark_node
;
483 DECL_COMMON (decl
) = 0;
484 DECL_DEFER_OUTPUT (decl
) = 0;
490 /* Return a field that is the size of the union, if an equivalence has
491 overlapping initializers. Merge the initializers into a single
492 initializer for this new field, then free the old ones. */
495 get_init_field (segment_info
*head
, tree union_type
, tree
*field_init
,
496 record_layout_info rli
)
499 HOST_WIDE_INT length
= 0;
500 HOST_WIDE_INT offset
= 0;
501 unsigned HOST_WIDE_INT known_align
, desired_align
;
502 bool overlap
= false;
505 unsigned char *data
, *chk
;
506 vec
<constructor_elt
, va_gc
> *v
= NULL
;
508 tree type
= unsigned_char_type_node
;
511 /* Obtain the size of the union and check if there are any overlapping
513 for (s
= head
; s
; s
= s
->next
)
515 HOST_WIDE_INT slen
= s
->offset
+ s
->length
;
518 if (s
->offset
< offset
)
522 length
= length
< slen
? slen
: length
;
528 /* Now absorb all the initializer data into a single vector,
529 whilst checking for overlapping, unequal values. */
530 data
= XCNEWVEC (unsigned char, (size_t)length
);
531 chk
= XCNEWVEC (unsigned char, (size_t)length
);
533 /* TODO - change this when default initialization is implemented. */
534 memset (data
, '\0', (size_t)length
);
535 memset (chk
, '\0', (size_t)length
);
536 for (s
= head
; s
; s
= s
->next
)
538 gfc_merge_initializers (s
->sym
->ts
, s
->sym
->value
,
543 for (i
= 0; i
< length
; i
++)
544 CONSTRUCTOR_APPEND_ELT (v
, NULL
, build_int_cst (type
, data
[i
]));
549 /* Build a char[length] array to hold the initializers. Much of what
550 follows is borrowed from build_field, above. */
552 tmp
= build_int_cst (gfc_array_index_type
, length
- 1);
553 tmp
= build_range_type (gfc_array_index_type
,
554 gfc_index_zero_node
, tmp
);
555 tmp
= build_array_type (type
, tmp
);
556 field
= build_decl (gfc_current_locus
.lb
->location
,
557 FIELD_DECL
, NULL_TREE
, tmp
);
559 known_align
= BIGGEST_ALIGNMENT
;
561 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
562 if (desired_align
> known_align
)
563 DECL_PACKED (field
) = 1;
565 DECL_FIELD_CONTEXT (field
) = union_type
;
566 DECL_FIELD_OFFSET (field
) = size_int (0);
567 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
568 SET_DECL_OFFSET_ALIGN (field
, known_align
);
570 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
,
571 size_binop (PLUS_EXPR
,
572 DECL_FIELD_OFFSET (field
),
573 DECL_SIZE_UNIT (field
)));
575 init
= build_constructor (TREE_TYPE (field
), v
);
576 TREE_CONSTANT (init
) = 1;
580 for (s
= head
; s
; s
= s
->next
)
582 if (s
->sym
->value
== NULL
)
585 gfc_free_expr (s
->sym
->value
);
586 s
->sym
->value
= NULL
;
593 /* Declare memory for the common block or local equivalence, and create
594 backend declarations for all of the elements. */
597 create_common (gfc_common_head
*com
, segment_info
*head
, bool saw_equiv
)
599 segment_info
*s
, *next_s
;
603 tree field_init
= NULL_TREE
;
604 record_layout_info rli
;
606 bool is_init
= false;
607 bool is_saved
= false;
609 /* Declare the variables inside the common block.
610 If the current common block contains any equivalence object, then
611 make a UNION_TYPE node, otherwise RECORD_TYPE. This will let the
612 alias analyzer work well when there is no address overlapping for
613 common variables in the current common block. */
615 union_type
= make_node (UNION_TYPE
);
617 union_type
= make_node (RECORD_TYPE
);
619 rli
= start_record_layout (union_type
);
620 field_link
= &TYPE_FIELDS (union_type
);
622 /* Check for overlapping initializers and replace them with a single,
623 artificial field that contains all the data. */
625 field
= get_init_field (head
, union_type
, &field_init
, rli
);
629 if (field
!= NULL_TREE
)
633 field_link
= &DECL_CHAIN (field
);
636 for (s
= head
; s
; s
= s
->next
)
638 build_field (s
, union_type
, rli
);
640 /* Link the field into the type. */
641 *field_link
= s
->field
;
642 field_link
= &DECL_CHAIN (s
->field
);
644 /* Has initial value. */
648 /* Has SAVE attribute. */
649 if (s
->sym
->attr
.save
)
653 finish_record_layout (rli
, true);
656 decl
= build_common_decl (com
, union_type
, is_init
);
658 decl
= build_equiv_decl (union_type
, is_init
, is_saved
);
663 vec
<constructor_elt
, va_gc
> *v
= NULL
;
665 if (field
!= NULL_TREE
&& field_init
!= NULL_TREE
)
666 CONSTRUCTOR_APPEND_ELT (v
, field
, field_init
);
668 for (s
= head
; s
; s
= s
->next
)
672 /* Add the initializer for this field. */
673 tmp
= gfc_conv_initializer (s
->sym
->value
, &s
->sym
->ts
,
674 TREE_TYPE (s
->field
),
675 s
->sym
->attr
.dimension
,
677 || s
->sym
->attr
.allocatable
, false);
679 CONSTRUCTOR_APPEND_ELT (v
, s
->field
, tmp
);
683 gcc_assert (!v
->is_empty ());
684 ctor
= build_constructor (union_type
, v
);
685 TREE_CONSTANT (ctor
) = 1;
686 TREE_STATIC (ctor
) = 1;
687 DECL_INITIAL (decl
) = ctor
;
689 #ifdef ENABLE_CHECKING
692 unsigned HOST_WIDE_INT idx
;
693 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor
), idx
, field
, value
)
694 gcc_assert (TREE_CODE (field
) == FIELD_DECL
);
699 /* Build component reference for each variable. */
700 for (s
= head
; s
; s
= next_s
)
704 var_decl
= build_decl (s
->sym
->declared_at
.lb
->location
,
705 VAR_DECL
, DECL_NAME (s
->field
),
706 TREE_TYPE (s
->field
));
707 TREE_STATIC (var_decl
) = TREE_STATIC (decl
);
708 /* Mark the variable as used in order to avoid warnings about
710 TREE_USED (var_decl
) = 1;
711 if (s
->sym
->attr
.use_assoc
)
712 DECL_IGNORED_P (var_decl
) = 1;
713 if (s
->sym
->attr
.target
)
714 TREE_ADDRESSABLE (var_decl
) = 1;
715 /* Fake variables are not visible from other translation units. */
716 TREE_PUBLIC (var_decl
) = 0;
717 gfc_finish_decl_attrs (var_decl
, &s
->sym
->attr
);
719 /* To preserve identifier names in COMMON, chain to procedure
720 scope unless at top level in a module definition. */
722 && s
->sym
->ns
->proc_name
723 && s
->sym
->ns
->proc_name
->attr
.flavor
== FL_MODULE
)
724 var_decl
= pushdecl_top_level (var_decl
);
726 gfc_add_decl_to_function (var_decl
);
728 SET_DECL_VALUE_EXPR (var_decl
,
729 fold_build3_loc (input_location
, COMPONENT_REF
,
730 TREE_TYPE (s
->field
),
731 decl
, s
->field
, NULL_TREE
));
732 DECL_HAS_VALUE_EXPR_P (var_decl
) = 1;
733 GFC_DECL_COMMON_OR_EQUIV (var_decl
) = 1;
735 if (s
->sym
->attr
.assign
)
737 gfc_allocate_lang_decl (var_decl
);
738 GFC_DECL_ASSIGN (var_decl
) = 1;
739 GFC_DECL_STRING_LEN (var_decl
) = GFC_DECL_STRING_LEN (s
->field
);
740 GFC_DECL_ASSIGN_ADDR (var_decl
) = GFC_DECL_ASSIGN_ADDR (s
->field
);
743 s
->sym
->backend_decl
= var_decl
;
751 /* Given a symbol, find it in the current segment list. Returns NULL if
754 static segment_info
*
755 find_segment_info (gfc_symbol
*symbol
)
759 for (n
= current_segment
; n
; n
= n
->next
)
761 if (n
->sym
== symbol
)
769 /* Given an expression node, make sure it is a constant integer and return
773 get_mpz (gfc_expr
*e
)
776 if (e
->expr_type
!= EXPR_CONSTANT
)
777 gfc_internal_error ("get_mpz(): Not an integer constant");
779 return &e
->value
.integer
;
783 /* Given an array specification and an array reference, figure out the
784 array element number (zero based). Bounds and elements are guaranteed
785 to be constants. If something goes wrong we generate an error and
789 element_number (gfc_array_ref
*ar
)
791 mpz_t multiplier
, offset
, extent
, n
;
793 HOST_WIDE_INT i
, rank
;
797 mpz_init_set_ui (multiplier
, 1);
798 mpz_init_set_ui (offset
, 0);
802 for (i
= 0; i
< rank
; i
++)
804 if (ar
->dimen_type
[i
] != DIMEN_ELEMENT
)
805 gfc_internal_error ("element_number(): Bad dimension type");
807 mpz_sub (n
, *get_mpz (ar
->start
[i
]), *get_mpz (as
->lower
[i
]));
809 mpz_mul (n
, n
, multiplier
);
810 mpz_add (offset
, offset
, n
);
812 mpz_sub (extent
, *get_mpz (as
->upper
[i
]), *get_mpz (as
->lower
[i
]));
813 mpz_add_ui (extent
, extent
, 1);
815 if (mpz_sgn (extent
) < 0)
816 mpz_set_ui (extent
, 0);
818 mpz_mul (multiplier
, multiplier
, extent
);
821 i
= mpz_get_ui (offset
);
823 mpz_clear (multiplier
);
832 /* Given a single element of an equivalence list, figure out the offset
833 from the base symbol. For simple variables or full arrays, this is
834 simply zero. For an array element we have to calculate the array
835 element number and multiply by the element size. For a substring we
836 have to calculate the further reference. */
839 calculate_offset (gfc_expr
*e
)
841 HOST_WIDE_INT n
, element_size
, offset
;
842 gfc_typespec
*element_type
;
846 element_type
= &e
->symtree
->n
.sym
->ts
;
848 for (reference
= e
->ref
; reference
; reference
= reference
->next
)
849 switch (reference
->type
)
852 switch (reference
->u
.ar
.type
)
858 n
= element_number (&reference
->u
.ar
);
859 if (element_type
->type
== BT_CHARACTER
)
860 gfc_conv_const_charlen (element_type
->u
.cl
);
862 int_size_in_bytes (gfc_typenode_for_spec (element_type
));
863 offset
+= n
* element_size
;
867 gfc_error ("Bad array reference at %L", &e
->where
);
871 if (reference
->u
.ss
.start
!= NULL
)
872 offset
+= mpz_get_ui (*get_mpz (reference
->u
.ss
.start
)) - 1;
875 gfc_error ("Illegal reference type at %L as EQUIVALENCE object",
882 /* Add a new segment_info structure to the current segment. eq1 is already
883 in the list, eq2 is not. */
886 new_condition (segment_info
*v
, gfc_equiv
*eq1
, gfc_equiv
*eq2
)
888 HOST_WIDE_INT offset1
, offset2
;
891 offset1
= calculate_offset (eq1
->expr
);
892 offset2
= calculate_offset (eq2
->expr
);
894 a
= get_segment_info (eq2
->expr
->symtree
->n
.sym
,
895 v
->offset
+ offset1
- offset2
);
897 current_segment
= add_segments (current_segment
, a
);
901 /* Given two equivalence structures that are both already in the list, make
902 sure that this new condition is not violated, generating an error if it
906 confirm_condition (segment_info
*s1
, gfc_equiv
*eq1
, segment_info
*s2
,
909 HOST_WIDE_INT offset1
, offset2
;
911 offset1
= calculate_offset (eq1
->expr
);
912 offset2
= calculate_offset (eq2
->expr
);
914 if (s1
->offset
+ offset1
!= s2
->offset
+ offset2
)
915 gfc_error ("Inconsistent equivalence rules involving %qs at %L and "
916 "%qs at %L", s1
->sym
->name
, &s1
->sym
->declared_at
,
917 s2
->sym
->name
, &s2
->sym
->declared_at
);
921 /* Process a new equivalence condition. eq1 is know to be in segment f.
922 If eq2 is also present then confirm that the condition holds.
923 Otherwise add a new variable to the segment list. */
926 add_condition (segment_info
*f
, gfc_equiv
*eq1
, gfc_equiv
*eq2
)
930 n
= find_segment_info (eq2
->expr
->symtree
->n
.sym
);
933 new_condition (f
, eq1
, eq2
);
935 confirm_condition (f
, eq1
, n
, eq2
);
939 /* Given a segment element, search through the equivalence lists for unused
940 conditions that involve the symbol. Add these rules to the segment. */
943 find_equivalence (segment_info
*n
)
945 gfc_equiv
*e1
, *e2
, *eq
;
950 for (e1
= n
->sym
->ns
->equiv
; e1
; e1
= e1
->next
)
954 /* Search the equivalence list, including the root (first) element
955 for the symbol that owns the segment. */
956 for (e2
= e1
; e2
; e2
= e2
->eq
)
958 if (!e2
->used
&& e2
->expr
->symtree
->n
.sym
== n
->sym
)
965 /* Go to the next root element. */
971 /* Now traverse the equivalence list matching the offsets. */
972 for (e2
= e1
; e2
; e2
= e2
->eq
)
974 if (!e2
->used
&& e2
!= eq
)
976 add_condition (n
, eq
, e2
);
986 /* Add all symbols equivalenced within a segment. We need to scan the
987 segment list multiple times to include indirect equivalences. Since
988 a new segment_info can inserted at the beginning of the segment list,
989 depending on its offset, we have to force a final pass through the
990 loop by demanding that completion sees a pass with no matches; i.e.,
991 all symbols with equiv_built set and no new equivalences found. */
994 add_equivalences (bool *saw_equiv
)
1004 for (f
= current_segment
; f
; f
= f
->next
)
1006 if (!f
->sym
->equiv_built
)
1008 f
->sym
->equiv_built
= 1;
1009 seen_one
= find_equivalence (f
);
1019 /* Add a copy of this segment list to the namespace. */
1020 copy_equiv_list_to_ns (current_segment
);
1024 /* Returns the offset necessary to properly align the current equivalence.
1025 Sets *palign to the required alignment. */
1027 static HOST_WIDE_INT
1028 align_segment (unsigned HOST_WIDE_INT
*palign
)
1031 unsigned HOST_WIDE_INT offset
;
1032 unsigned HOST_WIDE_INT max_align
;
1033 unsigned HOST_WIDE_INT this_align
;
1034 unsigned HOST_WIDE_INT this_offset
;
1038 for (s
= current_segment
; s
; s
= s
->next
)
1040 this_align
= TYPE_ALIGN_UNIT (s
->field
);
1041 if (s
->offset
& (this_align
- 1))
1043 /* Field is misaligned. */
1044 this_offset
= this_align
- ((s
->offset
+ offset
) & (this_align
- 1));
1045 if (this_offset
& (max_align
- 1))
1047 /* Aligning this field would misalign a previous field. */
1048 gfc_error ("The equivalence set for variable %qs "
1049 "declared at %L violates alignment requirements",
1050 s
->sym
->name
, &s
->sym
->declared_at
);
1052 offset
+= this_offset
;
1054 max_align
= this_align
;
1057 *palign
= max_align
;
1062 /* Adjust segment offsets by the given amount. */
1065 apply_segment_offset (segment_info
*s
, HOST_WIDE_INT offset
)
1067 for (; s
; s
= s
->next
)
1068 s
->offset
+= offset
;
1072 /* Lay out a symbol in a common block. If the symbol has already been seen
1073 then check the location is consistent. Otherwise create segments
1074 for that symbol and all the symbols equivalenced with it. */
1076 /* Translate a single common block. */
1079 translate_common (gfc_common_head
*common
, gfc_symbol
*var_list
)
1083 segment_info
*common_segment
;
1084 HOST_WIDE_INT offset
;
1085 HOST_WIDE_INT current_offset
;
1086 unsigned HOST_WIDE_INT align
;
1089 common_segment
= NULL
;
1095 /* Add symbols to the segment. */
1096 for (sym
= var_list
; sym
; sym
= sym
->common_next
)
1098 current_segment
= common_segment
;
1099 s
= find_segment_info (sym
);
1101 /* Symbol has already been added via an equivalence. Multiple
1102 use associations of the same common block result in equiv_built
1103 being set but no information about the symbol in the segment. */
1104 if (s
&& sym
->equiv_built
)
1106 /* Ensure the current location is properly aligned. */
1107 align
= TYPE_ALIGN_UNIT (s
->field
);
1108 current_offset
= (current_offset
+ align
- 1) &~ (align
- 1);
1110 /* Verify that it ended up where we expect it. */
1111 if (s
->offset
!= current_offset
)
1113 gfc_error ("Equivalence for %qs does not match ordering of "
1114 "COMMON %qs at %L", sym
->name
,
1115 common
->name
, &common
->where
);
1120 /* A symbol we haven't seen before. */
1121 s
= current_segment
= get_segment_info (sym
, current_offset
);
1123 /* Add all objects directly or indirectly equivalenced with this
1125 add_equivalences (&saw_equiv
);
1127 if (current_segment
->offset
< 0)
1128 gfc_error ("The equivalence set for %qs cause an invalid "
1129 "extension to COMMON %qs at %L", sym
->name
,
1130 common
->name
, &common
->where
);
1132 if (flag_align_commons
)
1133 offset
= align_segment (&align
);
1137 /* The required offset conflicts with previous alignment
1138 requirements. Insert padding immediately before this
1140 if (warn_align_commons
)
1142 if (strcmp (common
->name
, BLANK_COMMON_NAME
))
1144 "Padding of %d bytes required before %qs in "
1145 "COMMON %qs at %L; reorder elements or use "
1146 "-fno-align-commons", (int)offset
,
1147 s
->sym
->name
, common
->name
, &common
->where
);
1150 "Padding of %d bytes required before %qs in "
1151 "COMMON at %L; reorder elements or use "
1152 "-fno-align-commons", (int)offset
,
1153 s
->sym
->name
, &common
->where
);
1157 /* Apply the offset to the new segments. */
1158 apply_segment_offset (current_segment
, offset
);
1159 current_offset
+= offset
;
1161 /* Add the new segments to the common block. */
1162 common_segment
= add_segments (common_segment
, current_segment
);
1165 /* The offset of the next common variable. */
1166 current_offset
+= s
->length
;
1169 if (common_segment
== NULL
)
1171 gfc_error ("COMMON '%s' at %L does not exist",
1172 common
->name
, &common
->where
);
1176 if (common_segment
->offset
!= 0 && warn_align_commons
)
1178 if (strcmp (common
->name
, BLANK_COMMON_NAME
))
1179 gfc_warning (OPT_Walign_commons
,
1180 "COMMON %qs at %L requires %d bytes of padding; "
1181 "reorder elements or use %<-fno-align-commons%>",
1182 common
->name
, &common
->where
, (int)common_segment
->offset
);
1184 gfc_warning (OPT_Walign_commons
,
1185 "COMMON at %L requires %d bytes of padding; "
1186 "reorder elements or use %<-fno-align-commons%>",
1187 &common
->where
, (int)common_segment
->offset
);
1190 create_common (common
, common_segment
, saw_equiv
);
1194 /* Create a new block for each merged equivalence list. */
1197 finish_equivalences (gfc_namespace
*ns
)
1201 gfc_common_head
* c
;
1202 HOST_WIDE_INT offset
;
1203 unsigned HOST_WIDE_INT align
;
1206 for (z
= ns
->equiv
; z
; z
= z
->next
)
1207 for (y
= z
->eq
; y
; y
= y
->eq
)
1211 sym
= z
->expr
->symtree
->n
.sym
;
1212 current_segment
= get_segment_info (sym
, 0);
1214 /* All objects directly or indirectly equivalenced with this
1216 add_equivalences (&dummy
);
1218 /* Align the block. */
1219 offset
= align_segment (&align
);
1221 /* Ensure all offsets are positive. */
1222 offset
-= current_segment
->offset
& ~(align
- 1);
1224 apply_segment_offset (current_segment
, offset
);
1226 /* Create the decl. If this is a module equivalence, it has a
1227 unique name, pointed to by z->module. This is written to a
1228 gfc_common_header to push create_common into using
1229 build_common_decl, so that the equivalence appears as an
1230 external symbol. Otherwise, a local declaration is built using
1231 build_equiv_decl. */
1234 c
= gfc_get_common_head ();
1235 /* We've lost the real location, so use the location of the
1236 enclosing procedure. */
1237 c
->where
= ns
->proc_name
->declared_at
;
1238 strcpy (c
->name
, z
->module
);
1243 create_common (c
, current_segment
, true);
1249 /* Work function for translating a named common block. */
1252 named_common (gfc_symtree
*st
)
1254 translate_common (st
->n
.common
, st
->n
.common
->head
);
1258 /* Translate the common blocks in a namespace. Unlike other variables,
1259 these have to be created before code, because the backend_decl depends
1260 on the rest of the common block. */
1263 gfc_trans_common (gfc_namespace
*ns
)
1267 /* Translate the blank common block. */
1268 if (ns
->blank_common
.head
!= NULL
)
1270 c
= gfc_get_common_head ();
1271 c
->where
= ns
->blank_common
.head
->common_head
->where
;
1272 strcpy (c
->name
, BLANK_COMMON_NAME
);
1273 translate_common (c
, ns
->blank_common
.head
);
1276 /* Translate all named common blocks. */
1277 gfc_traverse_symtree (ns
->common_root
, named_common
);
1279 /* Translate local equivalence. */
1280 finish_equivalences (ns
);
1282 /* Commit the newly created symbols for common blocks and module
1284 gfc_commit_symbols ();