cp-except.c

早期freebsd实现

/* Handle exceptional things in C++.
   Copyright (C) 1989, 1992 Free Software Foundation, Inc.
   Contributed by Michael Tiemann ([e-mail])

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */


/* High-level class interface. */

#define NULL 0

/* This should be part of `ansi_opname', or at least be defined by the std.  */
#define EXCEPTION_NAME_PREFIX "__ex"
#define EXCEPTION_NAME_LENGTH 4

#include "config.h"
#include "tree.h"
#include "rtl.h"
#include "cp-tree.h"
#include "flags.h"
/* On Suns this can get you to the right definition if you
   set the right value for TARGET.  */
#include <setjmp.h>
#ifdef sequent
/* Can you believe they forgot this?  */
#define _JBLEN 11
#endif

#ifndef _JBLEN
#define _JBLEN (sizeof(jmp_buf)/sizeof(int))
#endif

void init_exception_processing ();
void init_exception_processing_1 ();

/* If non-zero, a VAR_DECL whose cleanup will cause a throw to the
   next exception handler.  Its value says whether to throw or not.
   In the case of functions which do not issue a RAISE, it should be
   possible to optimize away this VAR_DECL (and overhead associated
   with it).  */
tree exception_throw_decl;
/* Use this to know that we did not set `exception_throw_decl',
   until GCC optimizer is smart enough to figure it out for itself.  */
int sets_exception_throw_decl;

/* The exception `type' currently in scope, or NULL_TREE if none.  */
tree current_exception_type;

/* The exception handler object for the given scope.  */
tree current_exception_decl;
rtx current_exception_name_as_rtx;
rtx current_exception_parms_as_rtx;

/* The ``object'' view of the current exception parameters.
   We cast up from the `parms' field to `current_exception_type'.  */
tree current_exception_object;

/* Cache `setjmp', `longjmp', `raise_exception', and `unhandled_exception'
   after default conversion.  Maybe later they will get built-in.  */
static tree BISJ, BILJ, BIR, BIUE;

/* Local variables which give the appearance that exception
   handling is part of the language and the execution model.  */

/* The type of the exception handler stack.  */
static tree EHS_type;

/* The global handler stack.  */
tree EHS_decl;

/* Cached component refs to fields of `EHS_decl'.  */
static tree EHS_prev, EHS_handler, EHS_parms, EHS_name;
static rtx EHS_parms_as_rtx, EHS_name_as_rtx;

/* The parameter names of this exception type.  */

static tree last_exception_fields;
static tree last_exception_field_types;

/* When ID is VOID_TYPE_NODE, it means ``raise all''.
   Cannot be inline, since it uses `alloca', and that
   breaks code which pushes the result of this function
   on the stack.  */
static tree
exception_object_name (prefix, id)
     tree prefix;
     tree id;
{
  /* First, cons up the `name' of this exception.  */
  char *name;
  int length = (id == void_type_node ? 3 : IDENTIFIER_LENGTH (id)) + EXCEPTION_NAME_LENGTH;

  if (prefix)
    length += IDENTIFIER_LENGTH (prefix) + 2;

  name = (char *)alloca (length);
  strcpy (name, EXCEPTION_NAME_PREFIX);
  length = EXCEPTION_NAME_LENGTH;
  if (prefix)
    {
      strcpy (name + length, IDENTIFIER_POINTER (prefix));
      name[length + IDENTIFIER_LENGTH (prefix)] = JOINER;
      length += IDENTIFIER_LENGTH (prefix) + 1;
    }
  if (id == void_type_node)
    strcpy (name + length, "all");
  else
    strcpy (name + length, IDENTIFIER_POINTER (id));
  return get_identifier (name);
}

tree
lookup_exception_cname (ctype, cname, raise_id)
     tree ctype, cname;
     tree raise_id;
{
  tree this_cname = TREE_PURPOSE (raise_id);
  if (this_cname == NULL_TREE)
    {
      if (cname)
	{
	  tree name = TREE_VALUE (raise_id);
	  if (purpose_member (name, CLASSTYPE_TAGS (ctype)))
	    this_cname = cname;
	}
    }
  else if (this_cname == void_type_node)
    this_cname = NULL_TREE;
  else if (TREE_CODE (this_cname) != IDENTIFIER_NODE)
    {
      sorry ("multiple scope refs in `cplus_expand_raise_stmt'");
      this_cname = error_mark_node;
    }
  return this_cname;
}

tree
lookup_exception_tname (oname)
     tree oname;
{
  return get_identifier (IDENTIFIER_POINTER (oname) + EXCEPTION_NAME_LENGTH);
}

tree
lookup_exception_object (cname, name, complain)
     tree cname, name;
     int complain;
{
  tree oname;
  tree decl;

  if (cname == void_type_node)
    cname = NULL_TREE;
  else if (cname && TREE_CODE (cname) != IDENTIFIER_NODE)
    {
      sorry ("multiple scope refs in `lookup_exception_object'");
      cname = NULL_TREE;
    }
  oname = exception_object_name (cname, name);
  decl = IDENTIFIER_GLOBAL_VALUE (oname);
  if (decl == NULL_TREE || TREE_CODE (decl) != VAR_DECL)
    {
      if (complain)
	{
	  push_obstacks_nochange ();

	  if (cname)
	    error ("no exception name object for name `%s::%s'",
		   IDENTIFIER_POINTER (cname),
		   IDENTIFIER_POINTER (name));
	  else
	    error ("no exception name object for name `%s'",
		   IDENTIFIER_POINTER (name));
	  end_temporary_allocation ();
	  /* Avoid further error messages.  */
	  pushdecl_top_level (build_lang_field_decl (VAR_DECL,
						     exception_object_name (cname, name),
						     error_mark_node));
	  pop_obstacks ();
	}
      return NULL_TREE;
    }
  return decl;
}

tree
lookup_exception_type (ctype, cname, raise_id)
     tree ctype, cname;
     tree raise_id;
{
  tree name = TREE_VALUE (raise_id);
  tree purpose = TREE_PURPOSE (raise_id);

  if (cname && purpose == NULL_TREE)
    purpose = cname;

  if (purpose && purpose != void_type_node)
    {
      tree link = NULL_TREE;

      if (TREE_CODE (purpose) != IDENTIFIER_NODE)
	{
	  sorry ("multiple scope refs in `lookup_exception_type'");
	  TREE_PURPOSE (raise_id) = NULL_TREE;
	  return NULL_TREE;
	}
      if (! is_aggr_typedef (purpose, 1))
	return NULL_TREE;
      ctype = IDENTIFIER_TYPE_VALUE (purpose);
      link = purpose_member (name, CLASSTYPE_TAGS (ctype));
      if (link)
	return TREE_VALUE (link);
    }

  ctype = lookup_name (name, 1);
  if (ctype && TREE_CODE (ctype) == TYPE_DECL)
    ctype = TREE_TYPE (ctype);
  if (ctype && TREE_CODE (ctype) == RECORD_TYPE
      && CLASSTYPE_DECLARED_EXCEPTION (ctype))
    return ctype;
  return NULL_TREE;
}

tree
finish_exception (e, list_of_fieldlists)
     tree e;
     tree list_of_fieldlists;
{
  tree parmtypes = NULL_TREE, name_field;
  tree cname = TYPE_NAME (e);

  if (TREE_CODE (cname) == TYPE_DECL)
    cname = DECL_NAME (cname);

  if (last_exception_fields)
    error ("cannot declare exceptions within exceptions");
  if (list_of_fieldlists && ! ANON_AGGRNAME_P (cname))
    error_with_aggr_type (e, "exception name `%s' must follow body declaration");
  if (list_of_fieldlists)
    {
      tree prev, field;

      /* Note: no public, private, or protected allowed.  */
      if (TREE_CHAIN (list_of_fieldlists))
	error ("visibility declarations invalid in exception declaration");
      else if (TREE_PURPOSE (list_of_fieldlists) != (tree)visibility_default)
	error ("visibility declarations invalid in exception declaration");
      TREE_PURPOSE (list_of_fieldlists) = (tree)visibility_default;

      /* Note also: no member function declarations allowed.  */
      for (prev = 0, field = TREE_VALUE (list_of_fieldlists);
	   field; prev = field, field = TREE_CHAIN (field))
	{
	  switch (TREE_CODE (field))
	    {
	    case FIELD_DECL:
	      /* ok.  */
	      parmtypes = tree_cons (NULL_TREE, TREE_TYPE (field), parmtypes);
	      continue;
	    case FUNCTION_DECL:
	      error_with_decl (field, "declaration of function `%s' in exception invalid");
	      break;
	    case VAR_DECL:
	      if (TREE_STATIC (field))
		error_with_decl (field, "declaration of static variable `%s' in exception invalid");
	      else
		error_with_decl (field, "declaration of constant field `%s' in exception invalid");
	      break;
	    case CONST_DECL:
	      error_with_decl (field, "declaration of enum value `%s' in exception invalid");
	      break;
	    case SCOPE_REF:
	      error ("use of `::' in exception context invalid");
	      break;
	    }
	  if (prev)
	    TREE_CHAIN (prev) = TREE_CHAIN (field);
	  else
	    TREE_VALUE (list_of_fieldlists) = TREE_CHAIN (field);
	}
    }

  /* Now that we've cleaned up the fields, add a name identifier at front.  */
  name_field = build_lang_field_decl (FIELD_DECL, get_identifier ("__name"),
				      ptr_type_node);
  if (list_of_fieldlists)
    {
      TREE_CHAIN (name_field) = TREE_VALUE (list_of_fieldlists);
      TREE_VALUE (list_of_fieldlists) = name_field;
    }
  else
    list_of_fieldlists = build_tree_list (NULL_TREE, name_field);

  last_exception_fields = TREE_VALUE (list_of_fieldlists);
  if (parmtypes)
    {
      last_exception_field_types = nreverse (parmtypes);
      /* Set the TREE_CHAIN of what is now at the end of the
	 list to `void_list_node'.  */
      TREE_CHAIN (parmtypes) = void_list_node;
    }
  else
    last_exception_field_types = void_list_node;

  popclass (0);

#if 0
  /* Remove aggregate types from the list of tags,
     since these appear at global scope.  */
  while (x && IS_AGGR_TYPE (TREE_VALUE (x)))
    x = TREE_CHAIN (x);
  CLASSTYPE_TAGS (t) = x;
  y = x;
  while (x)
    {
      if (IS_AGGR_TYPE (TREE_VALUE (x)))
	TREE_CHAIN (y) = TREE_CHAIN (x);
      x = TREE_CHAIN (x);
    }
#endif

  if (flag_cadillac)
    cadillac_finish_exception (e);

  return e;
}

void
finish_exception_decl (cname, decl)
     tree cname, decl;
{
  /* In cp-decl.h.  */
  extern tree last_function_parms;

  /* An exception declaration.  */
  tree t, ctor;
  tree parmdecls = NULL_TREE, fields;
  tree list_of_fieldlists = temp_tree_cons (NULL_TREE,
					    copy_list (last_exception_fields),
					    NULL_TREE);
  tree edecl = build_lang_field_decl (VAR_DECL,
				      exception_object_name (cname, DECL_NAME (decl)),
				      ptr_type_node);

  DECL_LANGUAGE (edecl) = lang_c;
  TREE_STATIC (edecl) = 1;
  TREE_PUBLIC (edecl) = 1;
  finish_decl (pushdecl (edecl), 0, 0, 0);

  /* Now instantiate the exception decl.  */
  t = xref_tag (exception_type_node, DECL_NAME (decl), NULL_TREE);

  /* finish_struct will pop this.  */
  pushclass (t, 0);

  /* Now add a constructor which takes as parameters all the types we
     just defined.  */
  ctor = build_lang_decl (FUNCTION_DECL, DECL_NAME (decl),
			  build_cplus_method_type (t, TYPE_POINTER_TO (t),
						   last_exception_field_types));
  /* Don't take `name'.  The constructor handles that.  */
  fields = TREE_CHAIN (TREE_VALUE (list_of_fieldlists));
  while (fields)
    {
      tree parm = build_decl (PARM_DECL, DECL_NAME (fields), TREE_TYPE (fields));
      /* Since there is a prototype, args are passed in their own types.  */
      DECL_ARG_TYPE (parm) = TREE_TYPE (parm);
#ifdef PROMOTE_PROTOTYPES
      if (TREE_CODE (TREE_TYPE (fields)) == INTEGER_TYPE
	  && TYPE_PRECISION (TREE_TYPE (fields)) < TYPE_PRECISION (integer_type_node))
	DECL_ARG_TYPE (parm) = integer_type_node;
#endif
      TREE_CHAIN (parm) = parmdecls;
      parmdecls = parm;
      fields = TREE_CHAIN (fields);
    }
  fields = TREE_VALUE (list_of_fieldlists);
  last_function_parms = nreverse (parmdecls);

  DECL_CONSTRUCTOR_P (ctor) = 1;
  TYPE_HAS_CONSTRUCTOR (t) = 1;
  grokclassfn (t, DECL_NAME (decl), ctor, NO_SPECIAL, NULL_TREE);
  DECL_EXTERNAL (ctor) = 1;
  TREE_STATIC (ctor) = 1;
  TREE_PUBLIC (ctor) = 0;
  DECL_INLINE (ctor) = 1;
  make_decl_rtl (ctor, 0, 1);
  finish_decl (ctor, NULL_TREE, 0, 0);
  TREE_CHAIN (ctor) = TREE_VALUE (list_of_fieldlists);
  TREE_VALUE (list_of_fieldlists) = ctor;