1 /* Implementation of Fortran 2003 Polymorphism.
2 Copyright (C) 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Paul Richard Thomas <pault@gcc.gnu.org>
5 and Janus Weil <janus@gcc.gnu.org>
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 3, or (at your option) any later
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
24 /* class.c -- This file contains the front end functions needed to service
25 the implementation of Fortran 2003 polymorphism and other
26 object-oriented features. */
29 /* Outline of the internal representation:
31 Each CLASS variable is encapsulated by a class container, which is a
32 structure with two fields:
33 * _data: A pointer to the actual data of the variable. This field has the
34 declared type of the class variable and its attributes
35 (pointer/allocatable/dimension/...).
36 * _vptr: A pointer to the vtable entry (see below) of the dynamic type.
38 For each derived type we set up a "vtable" entry, i.e. a structure with the
40 * _hash: A hash value serving as a unique identifier for this type.
41 * _size: The size in bytes of the derived type.
42 * _extends: A pointer to the vtable entry of the parent derived type.
43 * _def_init: A pointer to a default initialized variable of this type.
44 * _copy: A procedure pointer to a copying procedure.
45 After these follow procedure pointer components for the specific
46 type-bound procedures. */
52 #include "constructor.h"
55 /* Insert a reference to the component of the given name.
56 Only to be used with CLASS containers and vtables. */
59 gfc_add_component_ref (gfc_expr *e, const char *name)
61 gfc_ref **tail = &(e->ref);
63 gfc_symbol *derived = e->symtree->n.sym->ts.u.derived;
66 if ((*tail)->type == REF_COMPONENT)
67 derived = (*tail)->u.c.component->ts.u.derived;
68 if ((*tail)->type == REF_ARRAY && (*tail)->next == NULL)
70 tail = &((*tail)->next);
72 if (*tail != NULL && strcmp (name, "_data") == 0)
74 (*tail) = gfc_get_ref();
76 (*tail)->type = REF_COMPONENT;
77 (*tail)->u.c.sym = derived;
78 (*tail)->u.c.component = gfc_find_component (derived, name, true, true);
79 gcc_assert((*tail)->u.c.component);
81 e->ts = (*tail)->u.c.component->ts;
85 /* Build a NULL initializer for CLASS pointers,
86 initializing the _data component to NULL and
87 the _vptr component to the declared type. */
90 gfc_class_null_initializer (gfc_typespec *ts)
95 init = gfc_get_structure_constructor_expr (ts->type, ts->kind,
96 &ts->u.derived->declared_at);
99 for (comp = ts->u.derived->components; comp; comp = comp->next)
101 gfc_constructor *ctor = gfc_constructor_get();
102 if (strcmp (comp->name, "_vptr") == 0)
103 ctor->expr = gfc_lval_expr_from_sym (gfc_find_derived_vtab (ts->u.derived));
105 ctor->expr = gfc_get_null_expr (NULL);
106 gfc_constructor_append (&init->value.constructor, ctor);
113 /* Create a unique string identifier for a derived type, composed of its name
114 and module name. This is used to construct unique names for the class
115 containers and vtab symbols. */
118 get_unique_type_string (char *string, gfc_symbol *derived)
120 char dt_name[GFC_MAX_SYMBOL_LEN+1];
121 sprintf (dt_name, "%s", derived->name);
122 dt_name[0] = TOUPPER (dt_name[0]);
124 sprintf (string, "%s_%s", derived->module, dt_name);
125 else if (derived->ns->proc_name)
126 sprintf (string, "%s_%s", derived->ns->proc_name->name, dt_name);
128 sprintf (string, "_%s", dt_name);
132 /* A relative of 'get_unique_type_string' which makes sure the generated
133 string will not be too long (replacing it by a hash string if needed). */
136 get_unique_hashed_string (char *string, gfc_symbol *derived)
138 char tmp[2*GFC_MAX_SYMBOL_LEN+2];
139 get_unique_type_string (&tmp[0], derived);
140 /* If string is too long, use hash value in hex representation
141 (allow for extra decoration, cf. gfc_build_class_symbol)*/
142 if (strlen (tmp) > GFC_MAX_SYMBOL_LEN - 10)
144 int h = gfc_hash_value (derived);
145 sprintf (string, "%X", h);
148 strcpy (string, tmp);
152 /* Assign a hash value for a derived type. The algorithm is that of SDBM. */
155 gfc_hash_value (gfc_symbol *sym)
157 unsigned int hash = 0;
158 char c[2*(GFC_MAX_SYMBOL_LEN+1)];
161 get_unique_type_string (&c[0], sym);
164 for (i = 0; i < len; i++)
165 hash = (hash << 6) + (hash << 16) - hash + c[i];
167 /* Return the hash but take the modulus for the sake of module read,
168 even though this slightly increases the chance of collision. */
169 return (hash % 100000000);
173 /* Build a polymorphic CLASS entity, using the symbol that comes from
174 build_sym. A CLASS entity is represented by an encapsulating type,
175 which contains the declared type as '_data' component, plus a pointer
176 component '_vptr' which determines the dynamic type. */
179 gfc_build_class_symbol (gfc_typespec *ts, symbol_attribute *attr,
180 gfc_array_spec **as, bool delayed_vtab)
182 char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
189 gfc_fatal_error ("Polymorphic array at %C not yet supported");
193 /* Determine the name of the encapsulating type. */
194 get_unique_hashed_string (tname, ts->u.derived);
195 if ((*as) && (*as)->rank && attr->allocatable)
196 sprintf (name, "__class_%s_%d_a", tname, (*as)->rank);
197 else if ((*as) && (*as)->rank)
198 sprintf (name, "__class_%s_%d", tname, (*as)->rank);
199 else if (attr->pointer)
200 sprintf (name, "__class_%s_p", tname);
201 else if (attr->allocatable)
202 sprintf (name, "__class_%s_a", tname);
204 sprintf (name, "__class_%s", tname);
206 gfc_find_symbol (name, ts->u.derived->ns, 0, &fclass);
210 /* If not there, create a new symbol. */
211 fclass = gfc_new_symbol (name, ts->u.derived->ns);
212 st = gfc_new_symtree (&ts->u.derived->ns->sym_root, name);
214 gfc_set_sym_referenced (fclass);
216 fclass->ts.type = BT_UNKNOWN;
217 fclass->attr.abstract = ts->u.derived->attr.abstract;
218 if (ts->u.derived->f2k_derived)
219 fclass->f2k_derived = gfc_get_namespace (NULL, 0);
220 if (gfc_add_flavor (&fclass->attr, FL_DERIVED,
221 NULL, &gfc_current_locus) == FAILURE)
224 /* Add component '_data'. */
225 if (gfc_add_component (fclass, "_data", &c) == FAILURE)
228 c->ts.type = BT_DERIVED;
229 c->attr.access = ACCESS_PRIVATE;
230 c->ts.u.derived = ts->u.derived;
231 c->attr.class_pointer = attr->pointer;
232 c->attr.pointer = attr->pointer || attr->dummy;
233 c->attr.allocatable = attr->allocatable;
234 c->attr.dimension = attr->dimension;
235 c->attr.codimension = attr->codimension;
236 c->attr.abstract = ts->u.derived->attr.abstract;
238 c->initializer = NULL;
240 /* Add component '_vptr'. */
241 if (gfc_add_component (fclass, "_vptr", &c) == FAILURE)
243 c->ts.type = BT_DERIVED;
245 c->ts.u.derived = NULL;
248 vtab = gfc_find_derived_vtab (ts->u.derived);
250 c->ts.u.derived = vtab->ts.u.derived;
252 c->attr.access = ACCESS_PRIVATE;
256 /* Since the extension field is 8 bit wide, we can only have
257 up to 255 extension levels. */
258 if (ts->u.derived->attr.extension == 255)
260 gfc_error ("Maximum extension level reached with type '%s' at %L",
261 ts->u.derived->name, &ts->u.derived->declared_at);
265 fclass->attr.extension = ts->u.derived->attr.extension + 1;
266 fclass->attr.is_class = 1;
267 ts->u.derived = fclass;
268 attr->allocatable = attr->pointer = attr->dimension = 0;
269 (*as) = NULL; /* XXX */
274 /* Add a procedure pointer component to the vtype
275 to represent a specific type-bound procedure. */
278 add_proc_comp (gfc_symbol *vtype, const char *name, gfc_typebound_proc *tb)
281 c = gfc_find_component (vtype, name, true, true);
285 /* Add procedure component. */
286 if (gfc_add_component (vtype, name, &c) == FAILURE)
290 c->tb = XCNEW (gfc_typebound_proc);
293 c->attr.procedure = 1;
294 c->attr.proc_pointer = 1;
295 c->attr.flavor = FL_PROCEDURE;
296 c->attr.access = ACCESS_PRIVATE;
297 c->attr.external = 1;
299 c->attr.if_source = IFSRC_IFBODY;
301 else if (c->attr.proc_pointer && c->tb)
309 c->ts.interface = tb->u.specific->n.sym;
311 c->initializer = gfc_get_variable_expr (tb->u.specific);
316 /* Add all specific type-bound procedures in the symtree 'st' to a vtype. */
319 add_procs_to_declared_vtab1 (gfc_symtree *st, gfc_symbol *vtype)
325 add_procs_to_declared_vtab1 (st->left, vtype);
328 add_procs_to_declared_vtab1 (st->right, vtype);
330 if (st->n.tb && !st->n.tb->error
331 && !st->n.tb->is_generic && st->n.tb->u.specific)
332 add_proc_comp (vtype, st->name, st->n.tb);
336 /* Copy procedure pointers components from the parent type. */
339 copy_vtab_proc_comps (gfc_symbol *declared, gfc_symbol *vtype)
344 vtab = gfc_find_derived_vtab (declared);
346 for (cmp = vtab->ts.u.derived->components; cmp; cmp = cmp->next)
348 if (gfc_find_component (vtype, cmp->name, true, true))
351 add_proc_comp (vtype, cmp->name, cmp->tb);
356 /* Add procedure pointers for all type-bound procedures to a vtab. */
359 add_procs_to_declared_vtab (gfc_symbol *derived, gfc_symbol *vtype)
361 gfc_symbol* super_type;
363 super_type = gfc_get_derived_super_type (derived);
365 if (super_type && (super_type != derived))
367 /* Make sure that the PPCs appear in the same order as in the parent. */
368 copy_vtab_proc_comps (super_type, vtype);
369 /* Only needed to get the PPC initializers right. */
370 add_procs_to_declared_vtab (super_type, vtype);
373 if (derived->f2k_derived && derived->f2k_derived->tb_sym_root)
374 add_procs_to_declared_vtab1 (derived->f2k_derived->tb_sym_root, vtype);
376 if (derived->f2k_derived && derived->f2k_derived->tb_uop_root)
377 add_procs_to_declared_vtab1 (derived->f2k_derived->tb_uop_root, vtype);
381 /* Find (or generate) the symbol for a derived type's vtab. */
384 gfc_find_derived_vtab (gfc_symbol *derived)
387 gfc_symbol *vtab = NULL, *vtype = NULL, *found_sym = NULL, *def_init = NULL;
388 gfc_symbol *copy = NULL, *src = NULL, *dst = NULL;
390 /* Find the top-level namespace (MODULE or PROGRAM). */
391 for (ns = gfc_current_ns; ns; ns = ns->parent)
395 /* If the type is a class container, use the underlying derived type. */
396 if (derived->attr.is_class)
397 derived = gfc_get_derived_super_type (derived);
401 char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
403 get_unique_hashed_string (tname, derived);
404 sprintf (name, "__vtab_%s", tname);
406 /* Look for the vtab symbol in various namespaces. */
407 gfc_find_symbol (name, gfc_current_ns, 0, &vtab);
409 gfc_find_symbol (name, ns, 0, &vtab);
411 gfc_find_symbol (name, derived->ns, 0, &vtab);
415 gfc_get_symbol (name, ns, &vtab);
416 vtab->ts.type = BT_DERIVED;
417 if (gfc_add_flavor (&vtab->attr, FL_VARIABLE, NULL,
418 &gfc_current_locus) == FAILURE)
420 vtab->attr.target = 1;
421 vtab->attr.save = SAVE_EXPLICIT;
423 vtab->attr.access = ACCESS_PUBLIC;
424 gfc_set_sym_referenced (vtab);
425 sprintf (name, "__vtype_%s", tname);
427 gfc_find_symbol (name, ns, 0, &vtype);
431 gfc_symbol *parent = NULL, *parent_vtab = NULL;
433 gfc_get_symbol (name, ns, &vtype);
434 if (gfc_add_flavor (&vtype->attr, FL_DERIVED,
435 NULL, &gfc_current_locus) == FAILURE)
437 vtype->attr.access = ACCESS_PUBLIC;
438 vtype->attr.vtype = 1;
439 gfc_set_sym_referenced (vtype);
441 /* Add component '_hash'. */
442 if (gfc_add_component (vtype, "_hash", &c) == FAILURE)
444 c->ts.type = BT_INTEGER;
446 c->attr.access = ACCESS_PRIVATE;
447 c->initializer = gfc_get_int_expr (gfc_default_integer_kind,
448 NULL, derived->hash_value);
450 /* Add component '_size'. */
451 if (gfc_add_component (vtype, "_size", &c) == FAILURE)
453 c->ts.type = BT_INTEGER;
455 c->attr.access = ACCESS_PRIVATE;
456 /* Remember the derived type in ts.u.derived,
457 so that the correct initializer can be set later on
458 (in gfc_conv_structure). */
459 c->ts.u.derived = derived;
460 c->initializer = gfc_get_int_expr (gfc_default_integer_kind,
463 /* Add component _extends. */
464 if (gfc_add_component (vtype, "_extends", &c) == FAILURE)
467 c->attr.access = ACCESS_PRIVATE;
468 parent = gfc_get_derived_super_type (derived);
471 parent_vtab = gfc_find_derived_vtab (parent);
472 c->ts.type = BT_DERIVED;
473 c->ts.u.derived = parent_vtab->ts.u.derived;
474 c->initializer = gfc_get_expr ();
475 c->initializer->expr_type = EXPR_VARIABLE;
476 gfc_find_sym_tree (parent_vtab->name, parent_vtab->ns,
477 0, &c->initializer->symtree);
481 c->ts.type = BT_DERIVED;
482 c->ts.u.derived = vtype;
483 c->initializer = gfc_get_null_expr (NULL);
486 if (derived->components == NULL && !derived->attr.zero_comp)
488 /* At this point an error must have occurred.
489 Prevent further errors on the vtype components. */
494 /* Add component _def_init. */
495 if (gfc_add_component (vtype, "_def_init", &c) == FAILURE)
498 c->attr.access = ACCESS_PRIVATE;
499 c->ts.type = BT_DERIVED;
500 c->ts.u.derived = derived;
501 if (derived->attr.abstract)
502 c->initializer = gfc_get_null_expr (NULL);
505 /* Construct default initialization variable. */
506 sprintf (name, "__def_init_%s", tname);
507 gfc_get_symbol (name, ns, &def_init);
508 def_init->attr.target = 1;
509 def_init->attr.save = SAVE_EXPLICIT;
510 def_init->attr.access = ACCESS_PUBLIC;
511 def_init->attr.flavor = FL_VARIABLE;
512 gfc_set_sym_referenced (def_init);
513 def_init->ts.type = BT_DERIVED;
514 def_init->ts.u.derived = derived;
515 def_init->value = gfc_default_initializer (&def_init->ts);
517 c->initializer = gfc_lval_expr_from_sym (def_init);
520 /* Add component _copy. */
521 if (gfc_add_component (vtype, "_copy", &c) == FAILURE)
523 c->attr.proc_pointer = 1;
524 c->attr.access = ACCESS_PRIVATE;
525 c->tb = XCNEW (gfc_typebound_proc);
527 if (derived->attr.abstract)
528 c->initializer = gfc_get_null_expr (NULL);
531 /* Set up namespace. */
532 gfc_namespace *sub_ns = gfc_get_namespace (ns, 0);
533 sub_ns->sibling = ns->contained;
534 ns->contained = sub_ns;
535 sub_ns->resolved = 1;
536 /* Set up procedure symbol. */
537 sprintf (name, "__copy_%s", tname);
538 gfc_get_symbol (name, sub_ns, ©);
539 sub_ns->proc_name = copy;
540 copy->attr.flavor = FL_PROCEDURE;
541 copy->attr.if_source = IFSRC_DECL;
542 if (ns->proc_name->attr.flavor == FL_MODULE)
543 copy->module = ns->proc_name->name;
544 gfc_set_sym_referenced (copy);
545 /* Set up formal arguments. */
546 gfc_get_symbol ("src", sub_ns, &src);
547 src->ts.type = BT_DERIVED;
548 src->ts.u.derived = derived;
549 src->attr.flavor = FL_VARIABLE;
551 gfc_set_sym_referenced (src);
552 copy->formal = gfc_get_formal_arglist ();
553 copy->formal->sym = src;
554 gfc_get_symbol ("dst", sub_ns, &dst);
555 dst->ts.type = BT_DERIVED;
556 dst->ts.u.derived = derived;
557 dst->attr.flavor = FL_VARIABLE;
559 gfc_set_sym_referenced (dst);
560 copy->formal->next = gfc_get_formal_arglist ();
561 copy->formal->next->sym = dst;
563 sub_ns->code = gfc_get_code ();
564 sub_ns->code->op = EXEC_INIT_ASSIGN;
565 sub_ns->code->expr1 = gfc_lval_expr_from_sym (dst);
566 sub_ns->code->expr2 = gfc_lval_expr_from_sym (src);
567 /* Set initializer. */
568 c->initializer = gfc_lval_expr_from_sym (copy);
569 c->ts.interface = copy;
572 /* Add procedure pointers for type-bound procedures. */
573 add_procs_to_declared_vtab (derived, vtype);
577 vtab->ts.u.derived = vtype;
578 vtab->value = gfc_default_initializer (&vtab->ts);
585 /* It is unexpected to have some symbols added at resolution or code
586 generation time. We commit the changes in order to keep a clean state. */
589 gfc_commit_symbol (vtab);
591 gfc_commit_symbol (vtype);
593 gfc_commit_symbol (def_init);
595 gfc_commit_symbol (copy);
597 gfc_commit_symbol (src);
599 gfc_commit_symbol (dst);
608 /* General worker function to find either a type-bound procedure or a
609 type-bound user operator. */
612 find_typebound_proc_uop (gfc_symbol* derived, gfc_try* t,
613 const char* name, bool noaccess, bool uop,
619 /* Set correct symbol-root. */
620 gcc_assert (derived->f2k_derived);
621 root = (uop ? derived->f2k_derived->tb_uop_root
622 : derived->f2k_derived->tb_sym_root);
624 /* Set default to failure. */
628 /* Try to find it in the current type's namespace. */
629 res = gfc_find_symtree (root, name);
630 if (res && res->n.tb && !res->n.tb->error)
636 if (!noaccess && derived->attr.use_assoc
637 && res->n.tb->access == ACCESS_PRIVATE)
640 gfc_error ("'%s' of '%s' is PRIVATE at %L",
641 name, derived->name, where);
649 /* Otherwise, recurse on parent type if derived is an extension. */
650 if (derived->attr.extension)
652 gfc_symbol* super_type;
653 super_type = gfc_get_derived_super_type (derived);
654 gcc_assert (super_type);
656 return find_typebound_proc_uop (super_type, t, name,
657 noaccess, uop, where);
665 /* Find a type-bound procedure or user operator by name for a derived-type
666 (looking recursively through the super-types). */
669 gfc_find_typebound_proc (gfc_symbol* derived, gfc_try* t,
670 const char* name, bool noaccess, locus* where)
672 return find_typebound_proc_uop (derived, t, name, noaccess, false, where);
676 gfc_find_typebound_user_op (gfc_symbol* derived, gfc_try* t,
677 const char* name, bool noaccess, locus* where)
679 return find_typebound_proc_uop (derived, t, name, noaccess, true, where);
683 /* Find a type-bound intrinsic operator looking recursively through the
684 super-type hierarchy. */
687 gfc_find_typebound_intrinsic_op (gfc_symbol* derived, gfc_try* t,
688 gfc_intrinsic_op op, bool noaccess,
691 gfc_typebound_proc* res;
693 /* Set default to failure. */
697 /* Try to find it in the current type's namespace. */
698 if (derived->f2k_derived)
699 res = derived->f2k_derived->tb_op[op];
704 if (res && !res->error)
710 if (!noaccess && derived->attr.use_assoc
711 && res->access == ACCESS_PRIVATE)
714 gfc_error ("'%s' of '%s' is PRIVATE at %L",
715 gfc_op2string (op), derived->name, where);
723 /* Otherwise, recurse on parent type if derived is an extension. */
724 if (derived->attr.extension)
726 gfc_symbol* super_type;
727 super_type = gfc_get_derived_super_type (derived);
728 gcc_assert (super_type);
730 return gfc_find_typebound_intrinsic_op (super_type, t, op,
739 /* Get a typebound-procedure symtree or create and insert it if not yet
740 present. This is like a very simplified version of gfc_get_sym_tree for
741 tbp-symtrees rather than regular ones. */
744 gfc_get_tbp_symtree (gfc_symtree **root, const char *name)
748 result = gfc_find_symtree (*root, name);
751 result = gfc_new_symtree (root, name);