pt.c

gcc库的原代码,对编程有很大帮助.

		    goto maybe_error;
		  }
	      }
	    if (r == NULL_TREE)
	      {
	      no_match:
		cp_error
		  (found
		   ? "template for method `%D' doesn't match any in class `%T'"
		   : "method `%D' not found in class `%T'", name, ctx);
		if (in_decl)
		  cp_error_at ("in attempt to instantiate `%D' declared at this point in file", in_decl);
		return error_mark_node;
	      }
	  }
	else
	  {
	    r = DECL_NAME (t);
	    {
	      tree decls;
	      int got_it = 0;

	      decls = lookup_name_nonclass (r);
	      if (decls == NULL_TREE)
		/* no match */;
	      else if (TREE_CODE (decls) == TREE_LIST)
		for (decls = TREE_VALUE (decls); decls ;
		     decls = DECL_CHAIN (decls))
		  {
		    if (TREE_CODE (decls) == FUNCTION_DECL
			&& TREE_TYPE (decls) == type)
		      {
			got_it = 1;
			r = decls;
			break;
		      }
		  }
	      else
		{
		  tree val = decls;
		  decls = NULL_TREE;
		  if (TREE_CODE (val) == FUNCTION_DECL
		      && TREE_TYPE (val) == type)
		    {
		      got_it = 1;
		      r = val;
		    }
		}

	      if (!got_it)
		{
		  tree a = build_decl_overload (r, TYPE_VALUES (type),
						DECL_CONTEXT (t) != NULL_TREE);
		  r = build_lang_decl (FUNCTION_DECL, r, type);
		  DECL_ASSEMBLER_NAME (r) = a;
		}
	      else if (TREE_STATIC (r))
		{
		  /* This overrides the template version, use it. */
		  return r;
		}
	    }
	  }
	TREE_PUBLIC (r) = 1;
	DECL_EXTERNAL (r) = 1;
	TREE_STATIC (r) = 0;
	DECL_INTERFACE_KNOWN (r) = 0;
	DECL_INLINE (r) = DECL_INLINE (t);
	DECL_THIS_INLINE (r) = DECL_THIS_INLINE (t);
	TREE_READONLY (r) = TREE_READONLY (t);
	TREE_THIS_VOLATILE (r) = TREE_THIS_VOLATILE (t);
	{
#if 0				/* Maybe later.  -jason  */
	  struct tinst_level *til = tinst_for_decl();

	  /* should always be true under new approach */
	  if (til)
	    {
	      DECL_SOURCE_FILE (r) = til->file;
	      DECL_SOURCE_LINE (r) = til->line;
	    }
	  else
#endif
	    {
	      DECL_SOURCE_FILE (r) = DECL_SOURCE_FILE (t);
	      DECL_SOURCE_LINE (r) = DECL_SOURCE_LINE (t);
	    }
	}
	DECL_CLASS_CONTEXT (r) = tsubst (DECL_CLASS_CONTEXT (t), args, nargs, t);
	make_decl_rtl (r, NULL_PTR, 1);
	DECL_ARGUMENTS (r) = fnargs;
	DECL_RESULT (r) = result;
#if 0
	if (DECL_CONTEXT (t) == NULL_TREE
	    || TREE_CODE_CLASS (TREE_CODE (DECL_CONTEXT (t))) != 't')
	  push_overloaded_decl_top_level (r, 0);
#endif
	return r;
      }

    case PARM_DECL:
      {
	tree r;
	r = build_decl (PARM_DECL, DECL_NAME (t), type);
	DECL_INITIAL (r) = TREE_TYPE (r);
	DECL_ARTIFICIAL (r) = DECL_ARTIFICIAL (t);
#ifdef PROMOTE_PROTOTYPES
	if ((TREE_CODE (type) == INTEGER_TYPE
	     || TREE_CODE (type) == ENUMERAL_TYPE)
	    && TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node))
	  DECL_ARG_TYPE (r) = integer_type_node;
#endif
	if (TREE_CHAIN (t))
	  TREE_CHAIN (r) = tsubst (TREE_CHAIN (t), args, nargs, TREE_CHAIN (t));
	return r;
      }

    case TREE_LIST:
      {
	tree purpose, value, chain, result;
	int via_public, via_virtual, via_protected;

	if (t == void_list_node)
	  return t;

	via_public = TREE_VIA_PUBLIC (t);
	via_protected = TREE_VIA_PROTECTED (t);
	via_virtual = TREE_VIA_VIRTUAL (t);

	purpose = TREE_PURPOSE (t);
	if (purpose)
	  purpose = tsubst (purpose, args, nargs, in_decl);
	value = TREE_VALUE (t);
	if (value)
	  value = tsubst (value, args, nargs, in_decl);
	chain = TREE_CHAIN (t);
	if (chain && chain != void_type_node)
	  chain = tsubst (chain, args, nargs, in_decl);
	if (purpose == TREE_PURPOSE (t)
	    && value == TREE_VALUE (t)
	    && chain == TREE_CHAIN (t))
	  return t;
	result = hash_tree_cons (via_public, via_virtual, via_protected,
				 purpose, value, chain);
	TREE_PARMLIST (result) = TREE_PARMLIST (t);
	return result;
      }
    case TREE_VEC:
      {
	int len = TREE_VEC_LENGTH (t), need_new = 0, i;
	tree *elts = (tree *) alloca (len * sizeof (tree));
	bzero ((char *) elts, len * sizeof (tree));

	for (i = 0; i < len; i++)
	  {
	    elts[i] = tsubst (TREE_VEC_ELT (t, i), args, nargs, in_decl);
	    if (elts[i] != TREE_VEC_ELT (t, i))
	      need_new = 1;
	  }

	if (!need_new)
	  return t;

	t = make_tree_vec (len);
	for (i = 0; i < len; i++)
	  TREE_VEC_ELT (t, i) = elts[i];
	return t;
      }
    case POINTER_TYPE:
    case REFERENCE_TYPE:
      {
	tree r;
	enum tree_code code;
	if (type == TREE_TYPE (t))
	  return t;

	code = TREE_CODE (t);
	if (code == POINTER_TYPE)
	  r = build_pointer_type (type);
	else
	  r = build_reference_type (type);
	r = cp_build_type_variant (r, TYPE_READONLY (t), TYPE_VOLATILE (t));
	/* Will this ever be needed for TYPE_..._TO values?  */
	layout_type (r);
	return r;
      }
    case OFFSET_TYPE:
      return build_offset_type
	(tsubst (TYPE_OFFSET_BASETYPE (t), args, nargs, in_decl), type);
    case FUNCTION_TYPE:
    case METHOD_TYPE:
      {
	tree values = TYPE_ARG_TYPES (t);
	tree context = TYPE_CONTEXT (t);
	tree new_value;

	/* Don't bother recursing if we know it won't change anything.	*/
	if (values != void_list_node)
	  values = tsubst (values, args, nargs, in_decl);
	if (context)
	  context = tsubst (context, args, nargs, in_decl);
	/* Could also optimize cases where return value and
	   values have common elements (e.g., T min(const &T, const T&).  */

	/* If the above parameters haven't changed, just return the type.  */
	if (type == TREE_TYPE (t)
	    && values == TYPE_VALUES (t)
	    && context == TYPE_CONTEXT (t))
	  return t;

	/* Construct a new type node and return it.  */
	if (TREE_CODE (t) == FUNCTION_TYPE
	    && context == NULL_TREE)
	  {
	    new_value = build_function_type (type, values);
	  }
	else if (context == NULL_TREE)
	  {
	    tree base = tsubst (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t))),
				args, nargs, in_decl);
	    new_value = build_cplus_method_type (base, type,
						 TREE_CHAIN (values));
	  }
	else
	  {
	    new_value = make_node (TREE_CODE (t));
	    TREE_TYPE (new_value) = type;
	    TYPE_CONTEXT (new_value) = context;
	    TYPE_VALUES (new_value) = values;
	    TYPE_SIZE (new_value) = TYPE_SIZE (t);
	    TYPE_ALIGN (new_value) = TYPE_ALIGN (t);
	    TYPE_MODE (new_value) = TYPE_MODE (t);
	    if (TYPE_METHOD_BASETYPE (t))
	      TYPE_METHOD_BASETYPE (new_value) = tsubst (TYPE_METHOD_BASETYPE (t),
							 args, nargs, in_decl);
	    /* Need to generate hash value.  */
	    my_friendly_abort (84);
	  }
	new_value = build_type_variant (new_value,
					TYPE_READONLY (t),
					TYPE_VOLATILE (t));
	return new_value;
      }
    case ARRAY_TYPE:
      {
	tree domain = tsubst (TYPE_DOMAIN (t), args, nargs, in_decl);
	tree r;
	if (type == TREE_TYPE (t) && domain == TYPE_DOMAIN (t))
	  return t;
	r = build_cplus_array_type (type, domain);
	return r;
      }

    case UNINSTANTIATED_P_TYPE:
      {
	int nparms = TREE_VEC_LENGTH (DECL_TEMPLATE_PARMS (UPT_TEMPLATE (t)));
	tree argvec = make_tree_vec (nparms);
	tree parmvec = UPT_PARMS (t);
	int i;
	tree id, rt;
	for (i = 0; i < nparms; i++)
	  TREE_VEC_ELT (argvec, i) = tsubst (TREE_VEC_ELT (parmvec, i),
					     args, nargs, in_decl);
	id = lookup_template_class (DECL_NAME (UPT_TEMPLATE (t)), argvec, NULL_TREE);
	if (! IDENTIFIER_HAS_TYPE_VALUE (id)) {
	  instantiate_class_template(id, 0);
	  /* set up pending_classes */
	  add_pending_template (id);

	  TYPE_MAIN_VARIANT (IDENTIFIER_TYPE_VALUE (id)) =
	    IDENTIFIER_TYPE_VALUE (id);
	}
        rt = IDENTIFIER_TYPE_VALUE (id);

	/* kung: this part handles nested type in template definition */
        
	if ( !ANON_AGGRNAME_P (DECL_NAME(TYPE_NAME(t))))
          {
	    rt = search_nested_type_in_tmpl (rt, t);
          }

	return build_type_variant (rt, TYPE_READONLY (t), TYPE_VOLATILE (t));
      }

    case MINUS_EXPR:
    case PLUS_EXPR:
      return fold (build (TREE_CODE (t), TREE_TYPE (t),
			  tsubst (TREE_OPERAND (t, 0), args, nargs, in_decl),
			  tsubst (TREE_OPERAND (t, 1), args, nargs, in_decl)));

    case NEGATE_EXPR:
    case NOP_EXPR:
      return fold (build1 (TREE_CODE (t), TREE_TYPE (t),
			   tsubst (TREE_OPERAND (t, 0), args, nargs, in_decl)));

    default:
      sorry ("use of `%s' in function template",
	     tree_code_name [(int) TREE_CODE (t)]);
      return error_mark_node;
    }
}

tree
instantiate_template (tmpl, targ_ptr)
     tree tmpl, *targ_ptr;
{
  tree targs, fndecl;
  int i, len;
  struct pending_inline *p;
  struct template_info *t;
  struct obstack *old_fmp_obstack;
  extern struct obstack *function_maybepermanent_obstack;

  push_obstacks (&permanent_obstack, &permanent_obstack);
  old_fmp_obstack = function_maybepermanent_obstack;
  function_maybepermanent_obstack = &permanent_obstack;

  my_friendly_assert (TREE_CODE (tmpl) == TEMPLATE_DECL, 283);
  len = TREE_VEC_LENGTH (DECL_TEMPLATE_PARMS (tmpl));

  i = len;
  while (i--)
    targ_ptr[i] = copy_to_permanent (targ_ptr[i]);

  for (fndecl = DECL_TEMPLATE_INSTANTIATIONS (tmpl);
       fndecl; fndecl = TREE_CHAIN (fndecl))
    {
      tree *t1 = &TREE_VEC_ELT (TREE_PURPOSE (fndecl), 0);
      for (i = len - 1; i >= 0; i--)
	if (simple_cst_equal (t1[i], targ_ptr[i]) <= 0)
	  goto no_match;

      /* Here, we have a match.  */
      fndecl = TREE_VALUE (fndecl);
      goto exit;

    no_match:
      ;
    }

  targs = make_tree_vec (len);
  i = len;
  while (i--)
    TREE_VEC_ELT (targs, i) = targ_ptr[i];

  /* substitute template parameters */
  fndecl = tsubst (DECL_RESULT (tmpl), targ_ptr,
		   TREE_VEC_LENGTH (targs), tmpl);

  if (fndecl == error_mark_node)
    goto exit;

  assemble_external (fndecl);

  /* If it's a static member fn in the template, we need to change it
     into a FUNCTION_TYPE and chop off its this pointer.  */
  if (TREE_CODE (TREE_TYPE (DECL_RESULT (tmpl))) == METHOD_TYPE
      && DECL_STATIC_FUNCTION_P (fndecl))
    {
      revert_static_member_fn (&DECL_RESULT (tmpl), NULL, NULL);
      /* Chop off the this pointer that grokclassfn so kindly added
	 for us (it didn't know yet if the fn was static or not).  */
      DECL_ARGUMENTS (fndecl) = TREE_CHAIN (DECL_ARGUMENTS (fndecl));
    }
     
  t = DECL_TEMPLATE_INFO (tmpl);

  /* If we have a preexisting version of this function, don't expand
     the template version, use the other instead.  */
  if (TREE_STATIC (fndecl) || DECL_TEMPLATE_SPECIALIZATION (fndecl))
    {
      SET_DECL_TEMPLATE_SPECIALIZATION (fndecl);
      p = (struct pending_inline *)0;
    }
  else if (t->text)
    {
      SET_DECL_IMPLICIT_INSTANTIATION (fndecl);
      repo_template_used (fndecl);
      p = (struct pending_inline *) permalloc (sizeof (struct pending_inline));
      p->parm_vec = t->parm_vec;
      p->bindings = targs;
      p->can_free = 0;
      p->deja_vu = 0;
      p->buf = t->text;
      p->len = t->length;
      p->fndecl = fndecl;
      {
	int l = lineno;
	char * f = input_filename;

	lineno = p->lineno = t->lineno;
	input_filename = p->filename = t->filename;

	extract_interface_info ();

	if (interface_unknown && flag_external_templates)
	  {
	    if (DECL_CLASS_CONTEXT (fndecl)
		&& CLASSTYPE_INTERFACE_KNOWN (DECL_CLASS_CONTEXT (fndecl)))
	      {
		interface_unknown = 0;
		interface_only
		  = CLASSTYPE_INTERFACE_ONLY (DECL_CLASS_CONTEXT (fndecl));
	      }
	    else if (! DECL_IN_SYSTEM_HEADER (tmpl))
	      warn_if_unknown_interface (tmpl);
	  }

	if (interface_unknown || ! flag_external_templates)
	  p->interface = 1;		/* unknown */
	else
	  p->interface = interface_only ? 0 : 2;

	lineno = l;
	input_filename = f;

	extract_interface_info ();
      }
    }
  else
    p = (struct pending_inline *)0;

  DECL_TEMPLATE_INSTANTIATIONS (tmpl) =
    tree_cons (targs, fndecl, DECL_TEMPLATE_INSTANTIATIONS (tmpl));

  if (p == (struct pending_inline *)0)
    {
      /* do nothing */
    }
  else if (DECL_INLINE (fndecl))
    {
      DECL_PENDING_INLINE_INFO (fndecl) = p;
      p->next = pending_inlines;
      pending_inlines = p;
    }
  else
    {
      p->next = pending_template_expansions;
      pending_template_expansions = p;
    }
 exit:
  function_maybepermanent_obstack = old_fmp_obstack;
  pop_obstacks ();

  return fndecl;
}

/* classlevel should now never be true.  jason 4/12/94 */
void
undo_template_name_overload (id, classlevel)
     tree id;
     int classlevel;
{
  tree template;

  template = IDENTIFIER_TEMPLATE (id);
  if (!template)
    return;