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)
121 sprintf (string, "%s_%s", derived->module, derived->name);
122 else if (derived->ns->proc_name)
123 sprintf (string, "%s_%s", derived->ns->proc_name->name, derived->name);
125 sprintf (string, "_%s", derived->name);
129 /* A relative of 'get_unique_type_string' which makes sure the generated
130 string will not be too long (replacing it by a hash string if needed). */
133 get_unique_hashed_string (char *string, gfc_symbol *derived)
135 char tmp[2*GFC_MAX_SYMBOL_LEN+2];
136 get_unique_type_string (&tmp[0], derived);
137 /* If string is too long, use hash value in hex representation
138 (allow for extra decoration, cf. gfc_build_class_symbol)*/
139 if (strlen (tmp) > GFC_MAX_SYMBOL_LEN - 10)
141 int h = gfc_hash_value (derived);
142 sprintf (string, "%X", h);
145 strcpy (string, tmp);
149 /* Assign a hash value for a derived type. The algorithm is that of SDBM. */
152 gfc_hash_value (gfc_symbol *sym)
154 unsigned int hash = 0;
155 char c[2*(GFC_MAX_SYMBOL_LEN+1)];
158 get_unique_type_string (&c[0], sym);
161 for (i = 0; i < len; i++)
162 hash = (hash << 6) + (hash << 16) - hash + c[i];
164 /* Return the hash but take the modulus for the sake of module read,
165 even though this slightly increases the chance of collision. */
166 return (hash % 100000000);
170 /* Build a polymorphic CLASS entity, using the symbol that comes from
171 build_sym. A CLASS entity is represented by an encapsulating type,
172 which contains the declared type as '_data' component, plus a pointer
173 component '_vptr' which determines the dynamic type. */
176 gfc_build_class_symbol (gfc_typespec *ts, symbol_attribute *attr,
177 gfc_array_spec **as, bool delayed_vtab)
179 char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
184 /* Determine the name of the encapsulating type. */
185 get_unique_hashed_string (tname, ts->u.derived);
186 if ((*as) && (*as)->rank && attr->allocatable)
187 sprintf (name, "__class_%s_%d_a", tname, (*as)->rank);
188 else if ((*as) && (*as)->rank)
189 sprintf (name, "__class_%s_%d", tname, (*as)->rank);
190 else if (attr->pointer)
191 sprintf (name, "__class_%s_p", tname);
192 else if (attr->allocatable)
193 sprintf (name, "__class_%s_a", tname);
195 sprintf (name, "__class_%s", tname);
197 gfc_find_symbol (name, ts->u.derived->ns, 0, &fclass);
201 /* If not there, create a new symbol. */
202 fclass = gfc_new_symbol (name, ts->u.derived->ns);
203 st = gfc_new_symtree (&ts->u.derived->ns->sym_root, name);
205 gfc_set_sym_referenced (fclass);
207 fclass->ts.type = BT_UNKNOWN;
208 fclass->attr.abstract = ts->u.derived->attr.abstract;
209 if (ts->u.derived->f2k_derived)
210 fclass->f2k_derived = gfc_get_namespace (NULL, 0);
211 if (gfc_add_flavor (&fclass->attr, FL_DERIVED,
212 NULL, &gfc_current_locus) == FAILURE)
215 /* Add component '_data'. */
216 if (gfc_add_component (fclass, "_data", &c) == FAILURE)
219 c->ts.type = BT_DERIVED;
220 c->attr.access = ACCESS_PRIVATE;
221 c->ts.u.derived = ts->u.derived;
222 c->attr.class_pointer = attr->pointer;
223 c->attr.pointer = attr->pointer || attr->dummy;
224 c->attr.allocatable = attr->allocatable;
225 c->attr.dimension = attr->dimension;
226 c->attr.codimension = attr->codimension;
227 c->attr.abstract = ts->u.derived->attr.abstract;
229 c->initializer = NULL;
231 /* Add component '_vptr'. */
232 if (gfc_add_component (fclass, "_vptr", &c) == FAILURE)
234 c->ts.type = BT_DERIVED;
236 c->ts.u.derived = NULL;
239 vtab = gfc_find_derived_vtab (ts->u.derived);
241 c->ts.u.derived = vtab->ts.u.derived;
243 c->attr.access = ACCESS_PRIVATE;
247 /* Since the extension field is 8 bit wide, we can only have
248 up to 255 extension levels. */
249 if (ts->u.derived->attr.extension == 255)
251 gfc_error ("Maximum extension level reached with type '%s' at %L",
252 ts->u.derived->name, &ts->u.derived->declared_at);
256 fclass->attr.extension = ts->u.derived->attr.extension + 1;
257 fclass->attr.is_class = 1;
258 ts->u.derived = fclass;
259 attr->allocatable = attr->pointer = attr->dimension = 0;
260 (*as) = NULL; /* XXX */
265 /* Add a procedure pointer component to the vtype
266 to represent a specific type-bound procedure. */
269 add_proc_comp (gfc_symbol *vtype, const char *name, gfc_typebound_proc *tb)
272 c = gfc_find_component (vtype, name, true, true);
276 /* Add procedure component. */
277 if (gfc_add_component (vtype, name, &c) == FAILURE)
281 c->tb = XCNEW (gfc_typebound_proc);
284 c->attr.procedure = 1;
285 c->attr.proc_pointer = 1;
286 c->attr.flavor = FL_PROCEDURE;
287 c->attr.access = ACCESS_PRIVATE;
288 c->attr.external = 1;
290 c->attr.if_source = IFSRC_IFBODY;
292 else if (c->attr.proc_pointer && c->tb)
300 c->ts.interface = tb->u.specific->n.sym;
302 c->initializer = gfc_get_variable_expr (tb->u.specific);
307 /* Add all specific type-bound procedures in the symtree 'st' to a vtype. */
310 add_procs_to_declared_vtab1 (gfc_symtree *st, gfc_symbol *vtype)
316 add_procs_to_declared_vtab1 (st->left, vtype);
319 add_procs_to_declared_vtab1 (st->right, vtype);
321 if (st->n.tb && !st->n.tb->error
322 && !st->n.tb->is_generic && st->n.tb->u.specific)
323 add_proc_comp (vtype, st->name, st->n.tb);
327 /* Copy procedure pointers components from the parent type. */
330 copy_vtab_proc_comps (gfc_symbol *declared, gfc_symbol *vtype)
335 vtab = gfc_find_derived_vtab (declared);
337 for (cmp = vtab->ts.u.derived->components; cmp; cmp = cmp->next)
339 if (gfc_find_component (vtype, cmp->name, true, true))
342 add_proc_comp (vtype, cmp->name, cmp->tb);
347 /* Add procedure pointers for all type-bound procedures to a vtab. */
350 add_procs_to_declared_vtab (gfc_symbol *derived, gfc_symbol *vtype)
352 gfc_symbol* super_type;
354 super_type = gfc_get_derived_super_type (derived);
356 if (super_type && (super_type != derived))
358 /* Make sure that the PPCs appear in the same order as in the parent. */
359 copy_vtab_proc_comps (super_type, vtype);
360 /* Only needed to get the PPC initializers right. */
361 add_procs_to_declared_vtab (super_type, vtype);
364 if (derived->f2k_derived && derived->f2k_derived->tb_sym_root)
365 add_procs_to_declared_vtab1 (derived->f2k_derived->tb_sym_root, vtype);
367 if (derived->f2k_derived && derived->f2k_derived->tb_uop_root)
368 add_procs_to_declared_vtab1 (derived->f2k_derived->tb_uop_root, vtype);
372 /* Find (or generate) the symbol for a derived type's vtab. */
375 gfc_find_derived_vtab (gfc_symbol *derived)
378 gfc_symbol *vtab = NULL, *vtype = NULL, *found_sym = NULL, *def_init = NULL;
379 gfc_symbol *copy = NULL, *src = NULL, *dst = NULL;
381 /* Find the top-level namespace (MODULE or PROGRAM). */
382 for (ns = gfc_current_ns; ns; ns = ns->parent)
386 /* If the type is a class container, use the underlying derived type. */
387 if (derived->attr.is_class)
388 derived = gfc_get_derived_super_type (derived);
392 char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
394 get_unique_hashed_string (tname, derived);
395 sprintf (name, "__vtab_%s", tname);
397 /* Look for the vtab symbol in various namespaces. */
398 gfc_find_symbol (name, gfc_current_ns, 0, &vtab);
400 gfc_find_symbol (name, ns, 0, &vtab);
402 gfc_find_symbol (name, derived->ns, 0, &vtab);
406 gfc_get_symbol (name, ns, &vtab);
407 vtab->ts.type = BT_DERIVED;
408 if (gfc_add_flavor (&vtab->attr, FL_VARIABLE, NULL,
409 &gfc_current_locus) == FAILURE)
411 vtab->attr.target = 1;
412 vtab->attr.save = SAVE_EXPLICIT;
414 vtab->attr.access = ACCESS_PUBLIC;
415 gfc_set_sym_referenced (vtab);
416 sprintf (name, "__vtype_%s", tname);
418 gfc_find_symbol (name, ns, 0, &vtype);
422 gfc_symbol *parent = NULL, *parent_vtab = NULL;
424 gfc_get_symbol (name, ns, &vtype);
425 if (gfc_add_flavor (&vtype->attr, FL_DERIVED,
426 NULL, &gfc_current_locus) == FAILURE)
428 vtype->attr.access = ACCESS_PUBLIC;
429 vtype->attr.vtype = 1;
430 gfc_set_sym_referenced (vtype);
432 /* Add component '_hash'. */
433 if (gfc_add_component (vtype, "_hash", &c) == FAILURE)
435 c->ts.type = BT_INTEGER;
437 c->attr.access = ACCESS_PRIVATE;
438 c->initializer = gfc_get_int_expr (gfc_default_integer_kind,
439 NULL, derived->hash_value);
441 /* Add component '_size'. */
442 if (gfc_add_component (vtype, "_size", &c) == FAILURE)
444 c->ts.type = BT_INTEGER;
446 c->attr.access = ACCESS_PRIVATE;
447 /* Remember the derived type in ts.u.derived,
448 so that the correct initializer can be set later on
449 (in gfc_conv_structure). */
450 c->ts.u.derived = derived;
451 c->initializer = gfc_get_int_expr (gfc_default_integer_kind,
454 /* Add component _extends. */
455 if (gfc_add_component (vtype, "_extends", &c) == FAILURE)
458 c->attr.access = ACCESS_PRIVATE;
459 parent = gfc_get_derived_super_type (derived);
462 parent_vtab = gfc_find_derived_vtab (parent);
463 c->ts.type = BT_DERIVED;
464 c->ts.u.derived = parent_vtab->ts.u.derived;
465 c->initializer = gfc_get_expr ();
466 c->initializer->expr_type = EXPR_VARIABLE;
467 gfc_find_sym_tree (parent_vtab->name, parent_vtab->ns,
468 0, &c->initializer->symtree);
472 c->ts.type = BT_DERIVED;
473 c->ts.u.derived = vtype;
474 c->initializer = gfc_get_null_expr (NULL);
477 if (derived->components == NULL && !derived->attr.zero_comp)
479 /* At this point an error must have occurred.
480 Prevent further errors on the vtype components. */
485 /* Add component _def_init. */
486 if (gfc_add_component (vtype, "_def_init", &c) == FAILURE)
489 c->attr.access = ACCESS_PRIVATE;
490 c->ts.type = BT_DERIVED;
491 c->ts.u.derived = derived;
492 if (derived->attr.abstract)
493 c->initializer = gfc_get_null_expr (NULL);
496 /* Construct default initialization variable. */
497 sprintf (name, "__def_init_%s", tname);
498 gfc_get_symbol (name, ns, &def_init);
499 def_init->attr.target = 1;
500 def_init->attr.save = SAVE_EXPLICIT;
501 def_init->attr.access = ACCESS_PUBLIC;
502 def_init->attr.flavor = FL_VARIABLE;
503 gfc_set_sym_referenced (def_init);
504 def_init->ts.type = BT_DERIVED;
505 def_init->ts.u.derived = derived;
506 def_init->value = gfc_default_initializer (&def_init->ts);
508 c->initializer = gfc_lval_expr_from_sym (def_init);
511 /* Add component _copy. */
512 if (gfc_add_component (vtype, "_copy", &c) == FAILURE)
514 c->attr.proc_pointer = 1;
515 c->attr.access = ACCESS_PRIVATE;
516 c->tb = XCNEW (gfc_typebound_proc);
518 if (derived->attr.abstract)
519 c->initializer = gfc_get_null_expr (NULL);
522 /* Set up namespace. */
523 gfc_namespace *sub_ns = gfc_get_namespace (ns, 0);
524 sub_ns->sibling = ns->contained;
525 ns->contained = sub_ns;
526 sub_ns->resolved = 1;
527 /* Set up procedure symbol. */
528 sprintf (name, "__copy_%s", tname);
529 gfc_get_symbol (name, sub_ns, ©);
530 sub_ns->proc_name = copy;
531 copy->attr.flavor = FL_PROCEDURE;
532 copy->attr.if_source = IFSRC_DECL;
533 if (ns->proc_name->attr.flavor == FL_MODULE)
534 copy->module = ns->proc_name->name;
535 gfc_set_sym_referenced (copy);
536 /* Set up formal arguments. */
537 gfc_get_symbol ("src", sub_ns, &src);
538 src->ts.type = BT_DERIVED;
539 src->ts.u.derived = derived;
540 src->attr.flavor = FL_VARIABLE;
542 gfc_set_sym_referenced (src);
543 copy->formal = gfc_get_formal_arglist ();
544 copy->formal->sym = src;
545 gfc_get_symbol ("dst", sub_ns, &dst);
546 dst->ts.type = BT_DERIVED;
547 dst->ts.u.derived = derived;
548 dst->attr.flavor = FL_VARIABLE;
550 gfc_set_sym_referenced (dst);
551 copy->formal->next = gfc_get_formal_arglist ();
552 copy->formal->next->sym = dst;
554 sub_ns->code = gfc_get_code ();
555 sub_ns->code->op = EXEC_INIT_ASSIGN;
556 sub_ns->code->expr1 = gfc_lval_expr_from_sym (dst);
557 sub_ns->code->expr2 = gfc_lval_expr_from_sym (src);
558 /* Set initializer. */
559 c->initializer = gfc_lval_expr_from_sym (copy);
560 c->ts.interface = copy;
563 /* Add procedure pointers for type-bound procedures. */
564 add_procs_to_declared_vtab (derived, vtype);
568 vtab->ts.u.derived = vtype;
569 vtab->value = gfc_default_initializer (&vtab->ts);
576 /* It is unexpected to have some symbols added at resolution or code
577 generation time. We commit the changes in order to keep a clean state. */
580 gfc_commit_symbol (vtab);
582 gfc_commit_symbol (vtype);
584 gfc_commit_symbol (def_init);
586 gfc_commit_symbol (copy);
588 gfc_commit_symbol (src);
590 gfc_commit_symbol (dst);
599 /* General worker function to find either a type-bound procedure or a
600 type-bound user operator. */
603 find_typebound_proc_uop (gfc_symbol* derived, gfc_try* t,
604 const char* name, bool noaccess, bool uop,
610 /* Set correct symbol-root. */
611 gcc_assert (derived->f2k_derived);
612 root = (uop ? derived->f2k_derived->tb_uop_root
613 : derived->f2k_derived->tb_sym_root);
615 /* Set default to failure. */
619 /* Try to find it in the current type's namespace. */
620 res = gfc_find_symtree (root, name);
621 if (res && res->n.tb && !res->n.tb->error)
627 if (!noaccess && derived->attr.use_assoc
628 && res->n.tb->access == ACCESS_PRIVATE)
631 gfc_error ("'%s' of '%s' is PRIVATE at %L",
632 name, derived->name, where);
640 /* Otherwise, recurse on parent type if derived is an extension. */
641 if (derived->attr.extension)
643 gfc_symbol* super_type;
644 super_type = gfc_get_derived_super_type (derived);
645 gcc_assert (super_type);
647 return find_typebound_proc_uop (super_type, t, name,
648 noaccess, uop, where);
656 /* Find a type-bound procedure or user operator by name for a derived-type
657 (looking recursively through the super-types). */
660 gfc_find_typebound_proc (gfc_symbol* derived, gfc_try* t,
661 const char* name, bool noaccess, locus* where)
663 return find_typebound_proc_uop (derived, t, name, noaccess, false, where);
667 gfc_find_typebound_user_op (gfc_symbol* derived, gfc_try* t,
668 const char* name, bool noaccess, locus* where)
670 return find_typebound_proc_uop (derived, t, name, noaccess, true, where);
674 /* Find a type-bound intrinsic operator looking recursively through the
675 super-type hierarchy. */
678 gfc_find_typebound_intrinsic_op (gfc_symbol* derived, gfc_try* t,
679 gfc_intrinsic_op op, bool noaccess,
682 gfc_typebound_proc* res;
684 /* Set default to failure. */
688 /* Try to find it in the current type's namespace. */
689 if (derived->f2k_derived)
690 res = derived->f2k_derived->tb_op[op];
695 if (res && !res->error)
701 if (!noaccess && derived->attr.use_assoc
702 && res->access == ACCESS_PRIVATE)
705 gfc_error ("'%s' of '%s' is PRIVATE at %L",
706 gfc_op2string (op), derived->name, where);
714 /* Otherwise, recurse on parent type if derived is an extension. */
715 if (derived->attr.extension)
717 gfc_symbol* super_type;
718 super_type = gfc_get_derived_super_type (derived);
719 gcc_assert (super_type);
721 return gfc_find_typebound_intrinsic_op (super_type, t, op,
730 /* Get a typebound-procedure symtree or create and insert it if not yet
731 present. This is like a very simplified version of gfc_get_sym_tree for
732 tbp-symtrees rather than regular ones. */
735 gfc_get_tbp_symtree (gfc_symtree **root, const char *name)
739 result = gfc_find_symtree (*root, name);
742 result = gfc_new_symtree (root, name);