2010-05-17 Janus Weil <janus@gcc.gnu.org>

	* class.c (gfc_add_component_ref,gfc_class_null_initializer,
	gfc_build_class_symbol,add_proc_component,add_proc_comps, 
	add_procs_to_declared_vtab1,copy_vtab_proc_comps,
	add_procs_to_declared_vtab,add_generic_specifics, 
	add_generics_to_declared_vtab,gfc_find_derived_vtab,
	find_typebound_proc_uop,gfc_find_typebound_proc,
	gfc_find_typebound_user_op,gfc_find_typebound_intrinsic_op, 
	gfc_get_tbp_symtree): Moved here from other places.
	* expr.c (gfc_add_component_ref,gfc_class_null_initializer): Move to
	class.c.
	* gfortran.h (gfc_build_class_symbol,gfc_find_derived_vtab,
	gfc_find_typebound_proc,gfc_find_typebound_user_op,
	gfc_find_typebound_intrinsic_op,gfc_get_tbp_symtree,
	gfc_add_component_ref, gfc_class_null_initializer): Moved to class.c.
	* Make-lang.in: Add class.o.
	* symbol.c (gfc_build_class_symbol,add_proc_component,add_proc_comps,
	add_procs_to_declared_vtab1,copy_vtab_proc_comps,
	add_procs_to_declared_vtab,add_generic_specifics,
	add_generics_to_declared_vtab,gfc_find_derived_vtab,
	find_typebound_proc_uop,gfc_find_typebound_proc,
	gfc_find_typebound_user_op,gfc_find_typebound_intrinsic_op,
	gfc_get_tbp_symtree): Move to class.c.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@159506 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 797 insertions, 0 deletions

diff --git a/gcc/fortran/class.c b/gcc/fortran/class.c
new file mode 100644
index 00000000000..37b9cf01590
--- /dev/null
+++ b/gcc/fortran/class.c
@@ -0,0 +1,797 @@
+/* Implementation of Fortran 2003 Polymorphism.
+   Copyright (C) 2009, 2010
+   Free Software Foundation, Inc.
+   Contributed by Paul Richard Thomas & Janus Weil
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+
+/* class.c -- This file contains the front end functions needed to service
+              the implementation of Fortran 2003 polymorphism and other
+              object-oriented features.  */
+
+
+/* Outline of the internal representation:
+
+   Each CLASS variable is encapsulated by a class container, which is a
+   structure with two fields:
+    * $data: A pointer to the actual data of the variable. This field has the
+             declared type of the class variable and its attributes
+             (pointer/allocatable/dimension/...).
+    * $vptr: A pointer to the vtable entry (see below) of the dynamic type.
+    
+   For each derived type we set up a "vtable" entry, i.e. a structure with the
+   following fields:
+    * $hash: A hash value serving as a unique identifier for this type.
+    * $size: The size in bytes of the derived type.
+    * $extends: A pointer to the vtable entry of the parent derived type.
+   In addition to these fields, each vtable entry contains additional procedure
+   pointer components, which contain pointers to the procedures which are bound
+   to the type's "methods" (type-bound procedures).  */
+
+
+#include "config.h"
+#include "system.h"
+#include "gfortran.h"
+#include "constructor.h"
+
+
+/* Insert a reference to the component of the given name.
+   Only to be used with CLASS containers.  */
+
+void
+gfc_add_component_ref (gfc_expr *e, const char *name)
+{
+  gfc_ref **tail = &(e->ref);
+  gfc_ref *next = NULL;
+  gfc_symbol *derived = e->symtree->n.sym->ts.u.derived;
+  while (*tail != NULL)
+    {
+      if ((*tail)->type == REF_COMPONENT)
+	derived = (*tail)->u.c.component->ts.u.derived;
+      if ((*tail)->type == REF_ARRAY && (*tail)->next == NULL)
+	break;
+      tail = &((*tail)->next);
+    }
+  if (*tail != NULL && strcmp (name, "$data") == 0)
+    next = *tail;
+  (*tail) = gfc_get_ref();
+  (*tail)->next = next;
+  (*tail)->type = REF_COMPONENT;
+  (*tail)->u.c.sym = derived;
+  (*tail)->u.c.component = gfc_find_component (derived, name, true, true);
+  gcc_assert((*tail)->u.c.component);
+  if (!next)
+    e->ts = (*tail)->u.c.component->ts;
+}
+
+
+/* Build a NULL initializer for CLASS pointers,
+   initializing the $data and $vptr components to zero.  */
+
+gfc_expr *
+gfc_class_null_initializer (gfc_typespec *ts)
+{
+  gfc_expr *init;
+  gfc_component *comp;
+  
+  init = gfc_get_structure_constructor_expr (ts->type, ts->kind,
+					     &ts->u.derived->declared_at);
+  init->ts = *ts;
+  
+  for (comp = ts->u.derived->components; comp; comp = comp->next)
+    {
+      gfc_constructor *ctor = gfc_constructor_get();
+      ctor->expr = gfc_get_expr ();
+      ctor->expr->expr_type = EXPR_NULL;
+      ctor->expr->ts = comp->ts;
+      gfc_constructor_append (&init->value.constructor, ctor);
+    }
+
+  return init;
+}
+
+
+/* Build a polymorphic CLASS entity, using the symbol that comes from
+   build_sym. A CLASS entity is represented by an encapsulating type,
+   which contains the declared type as '$data' component, plus a pointer
+   component '$vptr' which determines the dynamic type.  */
+
+gfc_try
+gfc_build_class_symbol (gfc_typespec *ts, symbol_attribute *attr,
+			gfc_array_spec **as, bool delayed_vtab)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 5];
+  gfc_symbol *fclass;
+  gfc_symbol *vtab;
+  gfc_component *c;
+
+  /* Determine the name of the encapsulating type.  */
+  if ((*as) && (*as)->rank && attr->allocatable)
+    sprintf (name, "class$%s_%d_a", ts->u.derived->name, (*as)->rank);
+  else if ((*as) && (*as)->rank)
+    sprintf (name, "class$%s_%d", ts->u.derived->name, (*as)->rank);
+  else if (attr->pointer)
+    sprintf (name, "class$%s_p", ts->u.derived->name);
+  else if (attr->allocatable)
+    sprintf (name, "class$%s_a", ts->u.derived->name);
+  else
+    sprintf (name, "class$%s", ts->u.derived->name);
+
+  gfc_find_symbol (name, ts->u.derived->ns, 0, &fclass);
+  if (fclass == NULL)
+    {
+      gfc_symtree *st;
+      /* If not there, create a new symbol.  */
+      fclass = gfc_new_symbol (name, ts->u.derived->ns);
+      st = gfc_new_symtree (&ts->u.derived->ns->sym_root, name);
+      st->n.sym = fclass;
+      gfc_set_sym_referenced (fclass);
+      fclass->refs++;
+      fclass->ts.type = BT_UNKNOWN;
+      fclass->attr.abstract = ts->u.derived->attr.abstract;
+      if (ts->u.derived->f2k_derived)
+	fclass->f2k_derived = gfc_get_namespace (NULL, 0);
+      if (gfc_add_flavor (&fclass->attr, FL_DERIVED,
+	  NULL, &gfc_current_locus) == FAILURE)
+	return FAILURE;
+
+      /* Add component '$data'.  */
+      if (gfc_add_component (fclass, "$data", &c) == FAILURE)
+	return FAILURE;
+      c->ts = *ts;
+      c->ts.type = BT_DERIVED;
+      c->attr.access = ACCESS_PRIVATE;
+      c->ts.u.derived = ts->u.derived;
+      c->attr.class_pointer = attr->pointer;
+      c->attr.pointer = attr->pointer || attr->dummy;
+      c->attr.allocatable = attr->allocatable;
+      c->attr.dimension = attr->dimension;
+      c->attr.codimension = attr->codimension;
+      c->attr.abstract = ts->u.derived->attr.abstract;
+      c->as = (*as);
+      c->initializer = NULL;
+
+      /* Add component '$vptr'.  */
+      if (gfc_add_component (fclass, "$vptr", &c) == FAILURE)
+	return FAILURE;
+      c->ts.type = BT_DERIVED;
+      if (delayed_vtab)
+	c->ts.u.derived = NULL;
+      else
+	{
+	  vtab = gfc_find_derived_vtab (ts->u.derived, false);
+	  gcc_assert (vtab);
+	  c->ts.u.derived = vtab->ts.u.derived;
+	}
+      c->attr.pointer = 1;
+    }
+
+  /* Since the extension field is 8 bit wide, we can only have
+     up to 255 extension levels.  */
+  if (ts->u.derived->attr.extension == 255)
+    {
+      gfc_error ("Maximum extension level reached with type '%s' at %L",
+		 ts->u.derived->name, &ts->u.derived->declared_at);
+      return FAILURE;
+    }
+    
+  fclass->attr.extension = ts->u.derived->attr.extension + 1;
+  fclass->attr.is_class = 1;
+  ts->u.derived = fclass;
+  attr->allocatable = attr->pointer = attr->dimension = 0;
+  (*as) = NULL;  /* XXX */
+  return SUCCESS;
+}
+
+
+static void
+add_proc_component (gfc_component *c, gfc_symbol *vtype,
+		    gfc_symtree *st, gfc_symbol *specific,
+		    bool is_generic, bool is_generic_specific)
+{
+  /* Add procedure component.  */
+  if (is_generic)
+    {
+      if (gfc_add_component (vtype, specific->name, &c) == FAILURE)
+	return;
+      c->ts.interface = specific;
+    }
+  else if (c && is_generic_specific)
+    {
+      c->ts.interface = st->n.tb->u.specific->n.sym;
+    }
+  else
+    {
+      c = gfc_find_component (vtype, st->name, true, true);
+      if (!c && gfc_add_component (vtype, st->name, &c) == FAILURE)
+	return;
+      c->ts.interface = st->n.tb->u.specific->n.sym;
+    }
+
+  if (!c->tb)
+    c->tb = XCNEW (gfc_typebound_proc);
+  *c->tb = *st->n.tb;
+  c->tb->ppc = 1;
+  c->attr.procedure = 1;
+  c->attr.proc_pointer = 1;
+  c->attr.flavor = FL_PROCEDURE;
+  c->attr.access = ACCESS_PRIVATE;
+  c->attr.external = 1;
+  c->attr.untyped = 1;
+  c->attr.if_source = IFSRC_IFBODY;
+
+  /* A static initializer cannot be used here because the specific
+     function is not a constant; internal compiler error: in
+     output_constant, at varasm.c:4623  */
+  c->initializer = NULL;
+}
+
+
+static void
+add_proc_comps (gfc_component *c, gfc_symbol *vtype,
+		gfc_symtree *st, bool is_generic)
+{
+  if (c == NULL && !is_generic)
+    {
+      add_proc_component (c, vtype, st, NULL, false, false);
+    }
+  else if (is_generic && st->n.tb && vtype->components == NULL)
+    {
+      gfc_tbp_generic* g;
+      gfc_symbol * specific;
+      for (g = st->n.tb->u.generic; g; g = g->next)
+	{
+	  if (!g->specific)
+	    continue;
+	  specific = g->specific->u.specific->n.sym;
+	  add_proc_component (NULL, vtype, st, specific, true, false);
+	}
+    }
+  else if (c->attr.proc_pointer && c->tb)
+    {
+      *c->tb = *st->n.tb;
+      c->tb->ppc = 1;
+      c->ts.interface = st->n.tb->u.specific->n.sym;	  
+    }
+}
+
+static void
+add_procs_to_declared_vtab1 (gfc_symtree *st, gfc_symbol *vtype,
+			     bool resolved)
+{
+  gfc_component *c;
+  gfc_symbol *generic;
+  char name[3 * GFC_MAX_SYMBOL_LEN + 10];
+
+  if (!st)
+    return;
+
+  if (st->left)
+    add_procs_to_declared_vtab1 (st->left, vtype, resolved);
+
+  if (st->right)
+    add_procs_to_declared_vtab1 (st->right, vtype, resolved);
+
+  if (!st->n.tb)
+    return;
+
+  if (!st->n.tb->is_generic && st->n.tb->u.specific)
+    {
+      c = gfc_find_component (vtype, st->name, true, true);
+      add_proc_comps (c, vtype, st, false);
+    }
+  else if (st->n.tb->is_generic)
+    {
+      c = gfc_find_component (vtype, st->name, true, true);
+
+      if (c == NULL)
+	{
+	  /* Add derived type component with generic name.  */
+	  if (gfc_add_component (vtype, st->name, &c) == FAILURE)
+	    return;
+	  c->ts.type = BT_DERIVED;
+	  c->attr.flavor = FL_VARIABLE;
+	  c->attr.pointer = 1;
+
+	  /* Add a special empty derived type as a placeholder.  */
+	  sprintf (name, "$empty");
+	  gfc_find_symbol (name, vtype->ns, 0, &generic);
+	  if (generic == NULL)
+	    {
+	      gfc_get_symbol (name, vtype->ns, &generic);
+	      generic->attr.flavor = FL_DERIVED;
+	      generic->refs++;
+	      gfc_set_sym_referenced (generic);
+	      generic->ts.type = BT_UNKNOWN;
+	      generic->attr.zero_comp = 1;
+	    }
+
+	  c->ts.u.derived = generic;
+	}
+    }
+}
+
+
+static void
+copy_vtab_proc_comps (gfc_symbol *declared, gfc_symbol *vtype,
+		      bool resolved)
+{
+  gfc_component *c, *cmp;
+  gfc_symbol *vtab;
+
+  vtab = gfc_find_derived_vtab (declared, resolved);
+
+  for (cmp = vtab->ts.u.derived->components; cmp; cmp = cmp->next)
+    {
+      if (gfc_find_component (vtype, cmp->name, true, true))
+	continue;
+
+      if (gfc_add_component (vtype, cmp->name, &c) == FAILURE)
+	return;
+
+      if (cmp->ts.type == BT_DERIVED)
+	{
+	  c->ts = cmp->ts;
+	  c->ts.u.derived = cmp->ts.u.derived;
+	  c->attr.flavor = FL_VARIABLE;
+	  c->attr.pointer = 1;
+	  c->initializer = NULL;
+	  continue;
+	}
+
+      c->tb = XCNEW (gfc_typebound_proc);
+      *c->tb = *cmp->tb;
+      c->attr.procedure = 1;
+      c->attr.proc_pointer = 1;
+      c->attr.flavor = FL_PROCEDURE;
+      c->attr.access = ACCESS_PRIVATE;
+      c->attr.external = 1;
+      c->ts.interface = cmp->ts.interface;
+      c->attr.untyped = 1;
+      c->attr.if_source = IFSRC_IFBODY;
+      c->initializer = NULL;
+    }
+}
+
+static void
+add_procs_to_declared_vtab (gfc_symbol *declared, gfc_symbol *vtype,
+			    gfc_symbol *derived, bool resolved)
+{
+  gfc_symbol* super_type;
+
+  super_type = gfc_get_derived_super_type (declared);
+
+  if (super_type && (super_type != declared))
+    add_procs_to_declared_vtab (super_type, vtype, derived, resolved);
+
+  if (declared != derived)
+    copy_vtab_proc_comps (declared, vtype, resolved);
+
+  if (declared->f2k_derived && declared->f2k_derived->tb_sym_root)
+    add_procs_to_declared_vtab1 (declared->f2k_derived->tb_sym_root,
+				 vtype, resolved);
+
+  if (declared->f2k_derived && declared->f2k_derived->tb_uop_root)
+    add_procs_to_declared_vtab1 (declared->f2k_derived->tb_uop_root,
+				 vtype, resolved);
+}
+
+
+static
+void add_generic_specifics (gfc_symbol *declared, gfc_symbol *vtab,
+			    const char *name)
+{
+  gfc_tbp_generic* g;
+  gfc_symbol * specific1;
+  gfc_symbol * specific2;
+  gfc_symtree *st = NULL;
+  gfc_component *c;
+
+  /* Find the generic procedure using the component name.  */
+  st = gfc_find_typebound_proc (declared, NULL, name, true, NULL);
+  if (st == NULL)
+    st = gfc_find_typebound_user_op (declared, NULL, name, true, NULL);
+
+  if (st == NULL)
+    return;
+
+  /* Add procedure pointer components for the specific procedures. */
+  for (g = st->n.tb->u.generic; g; g = g->next)
+    {
+      if (!g->specific)
+	continue;
+      specific1 = g->specific_st->n.tb->u.specific->n.sym;
+
+      c = vtab->ts.u.derived->components;
+      specific2 = NULL;
+
+      /* Override identical specific interface.  */
+      if (vtab->ts.u.derived->components)
+	{
+	  for (; c; c= c->next)
+	    {
+	      specific2 = c->ts.interface;
+	      if (gfc_compare_interfaces (specific2, specific1,
+					  specific1->name, 0, 0, NULL, 0))
+		break;
+	    }
+	}
+
+      add_proc_component (c, vtab->ts.u.derived, g->specific_st,
+			  NULL, false, true);
+      vtab->ts.u.derived->attr.zero_comp = 0;
+    }
+}
+
+
+static void
+add_generics_to_declared_vtab (gfc_symbol *declared, gfc_symbol *vtype,
+			       gfc_symbol *derived, bool resolved)
+{
+  gfc_component *cmp;
+  gfc_symtree *st = NULL;
+  gfc_symbol * vtab;
+  char name[2 * GFC_MAX_SYMBOL_LEN + 8];
+  gfc_symbol* super_type;
+
+  gcc_assert (resolved);
+
+  for (cmp = vtype->components; cmp; cmp = cmp->next)
+    {
+      if (cmp->ts.type != BT_DERIVED)
+	continue;
+
+      /* The only derived type that does not represent a generic
+	 procedure is the pointer to the parent vtab.  */
+      if (cmp->ts.u.derived
+	    && strcmp (cmp->ts.u.derived->name, "$extends") == 0)
+	continue;
+
+      /* Find the generic procedure using the component name.  */
+      st = gfc_find_typebound_proc (declared, NULL, cmp->name,
+				    true, NULL);
+      if (st == NULL)
+	st = gfc_find_typebound_user_op (declared, NULL, cmp->name,
+					 true, NULL);
+
+      /* Should be an error but we pass on it for now.  */
+      if (st == NULL || !st->n.tb->is_generic)
+	continue;
+
+      vtab = NULL;
+
+      /* Build a vtab and a special vtype, with only the procedure
+	 pointer fields, to carry the pointers to the specific
+	 procedures.  Should this name ever be changed, the same
+	 should be done in trans-expr.c(gfc_trans_assign_vtab_procs). */
+      sprintf (name, "vtab$%s$%s", vtype->name, cmp->name);
+      gfc_find_symbol (name, derived->ns, 0, &vtab);
+      if (vtab == NULL)
+	{
+	  gfc_get_symbol (name, derived->ns, &vtab);
+	  vtab->ts.type = BT_DERIVED;
+	  vtab->attr.flavor = FL_VARIABLE;
+	  vtab->attr.target = 1;
+	  vtab->attr.save = SAVE_EXPLICIT;
+	  vtab->attr.vtab = 1;
+	  vtab->refs++;
+	  gfc_set_sym_referenced (vtab);
+	  sprintf (name, "%s$%s", vtype->name, cmp->name);
+	  
+	  gfc_find_symbol (name, derived->ns, 0, &cmp->ts.u.derived);
+	  if (cmp->ts.u.derived == NULL
+		|| (strcmp (cmp->ts.u.derived->name, "$empty") == 0))
+	    {
+	      gfc_get_symbol (name, derived->ns, &cmp->ts.u.derived);
+	      if (gfc_add_flavor (&cmp->ts.u.derived->attr, FL_DERIVED,
+				  NULL, &gfc_current_locus) == FAILURE)
+		return;
+	      cmp->ts.u.derived->refs++;
+	      gfc_set_sym_referenced (cmp->ts.u.derived);
+	      cmp->ts.u.derived->attr.vtype = 1;
+	      cmp->ts.u.derived->attr.zero_comp = 1;
+	    }
+	  vtab->ts.u.derived = cmp->ts.u.derived;
+	}
+
+      /* Store this for later use in setting the pointer.  */
+      cmp->ts.interface = vtab;
+
+      if (vtab->ts.u.derived->components)
+	continue;
+
+      super_type = gfc_get_derived_super_type (declared);
+
+      if (super_type && (super_type != declared))
+	add_generic_specifics (super_type, vtab, cmp->name);
+
+      add_generic_specifics (declared, vtab, cmp->name);
+    }
+}
+
+
+/* Find the symbol for a derived type's vtab.  A vtab has the following
+   fields:
+   $hash	a hash value used to identify the derived type
+   $size	the size in bytes of the derived type
+   $extends	a pointer to the vtable of the parent derived type
+   then:
+   procedure pointer components for the specific typebound procedures
+   structure pointers to reduced vtabs that contain procedure
+   pointers to the specific procedures.  */
+
+gfc_symbol *
+gfc_find_derived_vtab (gfc_symbol *derived, bool resolved)
+{
+  gfc_namespace *ns;
+  gfc_symbol *vtab = NULL, *vtype = NULL;
+  char name[2 * GFC_MAX_SYMBOL_LEN + 8];
+
+  ns = gfc_current_ns;
+
+  for (; ns; ns = ns->parent)
+    if (!ns->parent)
+      break;
+
+  if (ns)
+    {
+      sprintf (name, "vtab$%s", derived->name);
+      gfc_find_symbol (name, ns, 0, &vtab);
+
+      if (vtab == NULL)
+	{
+	  gfc_get_symbol (name, ns, &vtab);
+	  vtab->ts.type = BT_DERIVED;
+	  vtab->attr.flavor = FL_VARIABLE;
+	  vtab->attr.target = 1;
+	  vtab->attr.save = SAVE_EXPLICIT;
+	  vtab->attr.vtab = 1;
+	  vtab->refs++;
+	  gfc_set_sym_referenced (vtab);
+	  sprintf (name, "vtype$%s", derived->name);
+	  
+	  gfc_find_symbol (name, ns, 0, &vtype);
+	  if (vtype == NULL)
+	    {
+	      gfc_component *c;
+	      gfc_symbol *parent = NULL, *parent_vtab = NULL;
+
+	      gfc_get_symbol (name, ns, &vtype);
+	      if (gfc_add_flavor (&vtype->attr, FL_DERIVED,
+				  NULL, &gfc_current_locus) == FAILURE)
+		return NULL;
+	      vtype->refs++;
+	      gfc_set_sym_referenced (vtype);
+
+	      /* Add component '$hash'.  */
+	      if (gfc_add_component (vtype, "$hash", &c) == FAILURE)
+		return NULL;
+	      c->ts.type = BT_INTEGER;
+	      c->ts.kind = 4;
+	      c->attr.access = ACCESS_PRIVATE;
+	      c->initializer = gfc_get_int_expr (gfc_default_integer_kind,
+						 NULL, derived->hash_value);
+
+	      /* Add component '$size'.  */
+	      if (gfc_add_component (vtype, "$size", &c) == FAILURE)
+		return NULL;
+	      c->ts.type = BT_INTEGER;
+	      c->ts.kind = 4;
+	      c->attr.access = ACCESS_PRIVATE;
+	      /* Remember the derived type in ts.u.derived,
+		 so that the correct initializer can be set later on
+		 (in gfc_conv_structure).  */
+	      c->ts.u.derived = derived;
+	      c->initializer = gfc_get_int_expr (gfc_default_integer_kind,
+						 NULL, 0);
+
+	      /* Add component $extends.  */
+	      if (gfc_add_component (vtype, "$extends", &c) == FAILURE)
+		return NULL;
+	      c->attr.pointer = 1;
+	      c->attr.access = ACCESS_PRIVATE;
+	      parent = gfc_get_derived_super_type (derived);
+	      if (parent)
+		{
+		  parent_vtab = gfc_find_derived_vtab (parent, resolved);
+		  c->ts.type = BT_DERIVED;
+		  c->ts.u.derived = parent_vtab->ts.u.derived;
+		  c->initializer = gfc_get_expr ();
+		  c->initializer->expr_type = EXPR_VARIABLE;
+		  gfc_find_sym_tree (parent_vtab->name, parent_vtab->ns,
+				     0, &c->initializer->symtree);
+		}
+	      else
+		{
+		  c->ts.type = BT_DERIVED;
+		  c->ts.u.derived = vtype;
+		  c->initializer = gfc_get_null_expr (NULL);
+		}
+
+	      add_procs_to_declared_vtab (derived, vtype, derived, resolved);
+	      vtype->attr.vtype = 1;
+	    }
+
+	  vtab->ts.u.derived = vtype;
+	  vtab->value = gfc_default_initializer (&vtab->ts);
+	}
+    }
+
+  /* Catch the call just before the backend declarations are built, so that
+     the generic procedures have been resolved and the specific procedures
+     have formal interfaces that can be compared.  */
+  if (resolved
+	&& vtab->ts.u.derived
+	&& vtab->ts.u.derived->backend_decl == NULL)
+    add_generics_to_declared_vtab (derived, vtab->ts.u.derived,
+				   derived, resolved);
+
+  return vtab;
+}
+
+
+/* General worker function to find either a type-bound procedure or a
+   type-bound user operator.  */
+
+static gfc_symtree*
+find_typebound_proc_uop (gfc_symbol* derived, gfc_try* t,
+			 const char* name, bool noaccess, bool uop,
+			 locus* where)
+{
+  gfc_symtree* res;
+  gfc_symtree* root;
+
+  /* Set correct symbol-root.  */
+  gcc_assert (derived->f2k_derived);
+  root = (uop ? derived->f2k_derived->tb_uop_root
+	      : derived->f2k_derived->tb_sym_root);
+
+  /* Set default to failure.  */
+  if (t)
+    *t = FAILURE;
+
+  /* Try to find it in the current type's namespace.  */
+  res = gfc_find_symtree (root, name);
+  if (res && res->n.tb && !res->n.tb->error)
+    {
+      /* We found one.  */
+      if (t)
+	*t = SUCCESS;
+
+      if (!noaccess && derived->attr.use_assoc
+	  && res->n.tb->access == ACCESS_PRIVATE)
+	{
+	  if (where)
+	    gfc_error ("'%s' of '%s' is PRIVATE at %L",
+		       name, derived->name, where);
+	  if (t)
+	    *t = FAILURE;
+	}
+
+      return res;
+    }
+
+  /* Otherwise, recurse on parent type if derived is an extension.  */
+  if (derived->attr.extension)
+    {
+      gfc_symbol* super_type;
+      super_type = gfc_get_derived_super_type (derived);
+      gcc_assert (super_type);
+
+      return find_typebound_proc_uop (super_type, t, name,
+				      noaccess, uop, where);
+    }
+
+  /* Nothing found.  */
+  return NULL;
+}
+
+
+/* Find a type-bound procedure or user operator by name for a derived-type
+   (looking recursively through the super-types).  */
+
+gfc_symtree*
+gfc_find_typebound_proc (gfc_symbol* derived, gfc_try* t,
+			 const char* name, bool noaccess, locus* where)
+{
+  return find_typebound_proc_uop (derived, t, name, noaccess, false, where);
+}
+
+gfc_symtree*
+gfc_find_typebound_user_op (gfc_symbol* derived, gfc_try* t,
+			    const char* name, bool noaccess, locus* where)
+{
+  return find_typebound_proc_uop (derived, t, name, noaccess, true, where);
+}
+
+
+/* Find a type-bound intrinsic operator looking recursively through the
+   super-type hierarchy.  */
+
+gfc_typebound_proc*
+gfc_find_typebound_intrinsic_op (gfc_symbol* derived, gfc_try* t,
+				 gfc_intrinsic_op op, bool noaccess,
+				 locus* where)
+{
+  gfc_typebound_proc* res;
+
+  /* Set default to failure.  */
+  if (t)
+    *t = FAILURE;
+
+  /* Try to find it in the current type's namespace.  */
+  if (derived->f2k_derived)
+    res = derived->f2k_derived->tb_op[op];
+  else  
+    res = NULL;
+
+  /* Check access.  */
+  if (res && !res->error)
+    {
+      /* We found one.  */
+      if (t)
+	*t = SUCCESS;
+
+      if (!noaccess && derived->attr.use_assoc
+	  && res->access == ACCESS_PRIVATE)
+	{
+	  if (where)
+	    gfc_error ("'%s' of '%s' is PRIVATE at %L",
+		       gfc_op2string (op), derived->name, where);
+	  if (t)
+	    *t = FAILURE;
+	}
+
+      return res;
+    }
+
+  /* Otherwise, recurse on parent type if derived is an extension.  */
+  if (derived->attr.extension)
+    {
+      gfc_symbol* super_type;
+      super_type = gfc_get_derived_super_type (derived);
+      gcc_assert (super_type);
+
+      return gfc_find_typebound_intrinsic_op (super_type, t, op,
+					      noaccess, where);
+    }
+
+  /* Nothing found.  */
+  return NULL;
+}
+
+
+/* Get a typebound-procedure symtree or create and insert it if not yet
+   present.  This is like a very simplified version of gfc_get_sym_tree for
+   tbp-symtrees rather than regular ones.  */
+
+gfc_symtree*
+gfc_get_tbp_symtree (gfc_symtree **root, const char *name)
+{
+  gfc_symtree *result;
+
+  result = gfc_find_symtree (*root, name);
+  if (!result)
+    {
+      result = gfc_new_symtree (root, name);
+      gcc_assert (result);
+      result->n.tb = NULL;
+    }
+
+  return result;
+}