pt.c

gcc库的原代码,对编程有很大帮助.

			 TREE_CODE (TREE_TYPE (TREE_TYPE (val))) == FUNCTION_TYPE
			 ? "a function" : "an object");
		  val = error_mark_node;
		}
	    }
	}

      if (val == error_mark_node)
	lost++;

      TREE_VEC_ELT (vec, i) = val;
    }
  if (lost)
    return error_mark_node;
  return vec;
}

/* Given class template name and parameter list, produce a user-friendly name
   for the instantiation.  */
static char *
mangle_class_name_for_template (name, parms, arglist)
     char *name;
     tree parms, arglist;
{
  static struct obstack scratch_obstack;
  static char *scratch_firstobj;
  int i, nparms;

  if (!scratch_firstobj)
    {
      gcc_obstack_init (&scratch_obstack);
      scratch_firstobj = obstack_alloc (&scratch_obstack, 1);
    }
  else
    obstack_free (&scratch_obstack, scratch_firstobj);

#if 0
#define buflen	sizeof(buf)
#define check	if (bufp >= buf+buflen-1) goto too_long
#define ccat(c) *bufp++=(c); check
#define advance	bufp+=strlen(bufp); check
#define cat(s)	strncpy(bufp, s, buf+buflen-bufp-1); advance
#else
#define check
#define ccat(c)	obstack_1grow (&scratch_obstack, (c));
#define advance
#define cat(s)	obstack_grow (&scratch_obstack, (s), strlen (s))
#endif

  cat (name);
  ccat ('<');
  nparms = TREE_VEC_LENGTH (parms);
  my_friendly_assert (nparms == TREE_VEC_LENGTH (arglist), 268);
  for (i = 0; i < nparms; i++)
    {
      tree parm = TREE_VALUE (TREE_VEC_ELT (parms, i));
      tree arg = TREE_VEC_ELT (arglist, i);

      if (i)
	ccat (',');

      if (TREE_CODE (parm) == TYPE_DECL)
	{
	  cat (type_as_string (arg, 0));
	  continue;
	}
      else
	my_friendly_assert (TREE_CODE (parm) == PARM_DECL, 269);

      if (TREE_CODE (arg) == TREE_LIST)
	{
	  /* New list cell was built because old chain link was in
	     use.  */
	  my_friendly_assert (TREE_PURPOSE (arg) == NULL_TREE, 270);
	  arg = TREE_VALUE (arg);
	}
      /* No need to check arglist against parmlist here; we did that
	 in coerce_template_parms, called from lookup_template_class.  */
      cat (expr_as_string (arg, 0));
    }
  {
    char *bufp = obstack_next_free (&scratch_obstack);
    int offset = 0;
    while (bufp[offset - 1] == ' ')
      offset--;
    obstack_blank_fast (&scratch_obstack, offset);

    /* B<C<char> >, not B<C<char>> */
    if (bufp[offset - 1] == '>')
      ccat (' ');
  }
  ccat ('>');
  ccat ('\0');
  return (char *) obstack_base (&scratch_obstack);

#if 0
 too_long:
#endif
  fatal ("out of (preallocated) string space creating template instantiation name");
  /* NOTREACHED */
  return NULL;
}

/* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
   parameters, find the desired type.

   D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
   Since ARGLIST is build on the decl_obstack, we must copy it here
   to keep it from being reclaimed when the decl storage is reclaimed.

   IN_DECL, if non-NULL, is the template declaration we are trying to
   instantiate.  */
tree
lookup_template_class (d1, arglist, in_decl)
     tree d1, arglist;
     tree in_decl;
{
  tree template, parmlist;
  char *mangled_name;
  tree id;

  my_friendly_assert (TREE_CODE (d1) == IDENTIFIER_NODE, 272);
  template = IDENTIFIER_GLOBAL_VALUE (d1); /* XXX */
  if (! template)
    template = IDENTIFIER_CLASS_VALUE (d1);
  /* With something like `template <class T> class X class X { ... };'
     we could end up with D1 having nothing but an IDENTIFIER_LOCAL_VALUE.
     We don't want to do that, but we have to deal with the situation, so
     let's give them some syntax errors to chew on instead of a crash.  */
  if (! template)
    return error_mark_node;
  if (TREE_CODE (template) != TEMPLATE_DECL)
    {
      cp_error ("non-template type `%T' used as a template", d1);
      if (in_decl)
	cp_error_at ("for template declaration `%D'", in_decl);
      return error_mark_node;
    }
  parmlist = DECL_TEMPLATE_PARMS (template);

  arglist = coerce_template_parms (parmlist, arglist, template);
  if (arglist == error_mark_node)
    return error_mark_node;
  if (uses_template_parms (arglist))
    {
      tree t = make_lang_type (UNINSTANTIATED_P_TYPE);
      tree d;
      id = make_anon_name ();
      d = build_decl (TYPE_DECL, id, t);
      TYPE_NAME (t) = d;
      TYPE_VALUES (t) = build_tree_list (template, arglist);
      pushdecl_top_level (d);
    }
  else
    {
      mangled_name = mangle_class_name_for_template (IDENTIFIER_POINTER (d1),
						     parmlist, arglist);
      id = get_identifier (mangled_name);
    }
  if (!IDENTIFIER_TEMPLATE (id))
    {
      arglist = copy_to_permanent (arglist);
      IDENTIFIER_TEMPLATE (id) = perm_tree_cons (template, arglist, NULL_TREE);
    }
  return id;
}

void
push_template_decls (parmlist, arglist, class_level)
     tree parmlist, arglist;
     int class_level;
{
  int i, nparms;

  /* Don't want to push values into global context.  */
  if (!class_level)
    {
      pushlevel (1);
      declare_pseudo_global_level ();
    }

  nparms = TREE_VEC_LENGTH (parmlist);

  for (i = 0; i < nparms; i++)
    {
      int requires_type, is_type;
      tree parm = TREE_VALUE (TREE_VEC_ELT (parmlist, i));
      tree arg = TREE_VEC_ELT (arglist, i);
      tree decl = 0;

      requires_type = TREE_CODE (parm) == TYPE_DECL;
      is_type = TREE_CODE_CLASS (TREE_CODE (arg)) == 't';
      if (is_type)
	{
	  /* add typename to namespace */
	  if (!requires_type)
	    {
	      error ("template use error: type provided where value needed");
	      continue;
	    }
	  decl = arg;
	  my_friendly_assert (TREE_CODE_CLASS (TREE_CODE (decl)) == 't', 273);
	  decl = build_decl (TYPE_DECL, DECL_NAME (parm), decl);
	}
      else
	{
	  /* add const decl to namespace */
	  tree val;
	  tree parmtype;
	  if (requires_type)
	    {
	      error ("template use error: value provided where type needed");
	      continue;
	    }
	  parmtype = tsubst (TREE_TYPE (parm), &TREE_VEC_ELT (arglist, 0),
			     TREE_VEC_LENGTH (arglist), NULL_TREE);
	  val = digest_init (parmtype, arg, (tree *) 0);
	  if (val != error_mark_node)
	    {
	      decl = build_decl (CONST_DECL, DECL_NAME (parm),
				 parmtype);
	      DECL_INITIAL (decl) = val;
	      TREE_READONLY (decl) = 1;
	    }
	}
      if (decl != 0)
	{
	  SET_DECL_ARTIFICIAL (decl);
	  layout_decl (decl, 0);
	  if (class_level)
	    pushdecl_class_level (decl);
	  else
	    pushdecl (decl);
	}
    }
}

void
pop_template_decls (parmlist, arglist, class_level)
     tree parmlist, arglist;
     int class_level;
{
  if (!class_level)
    poplevel (0, 0, 0);
}

/* Should be defined in parse.h.  */
extern int yychar;

int
uses_template_parms (t)
     tree t;
{
  if (!t)
    return 0;
  switch (TREE_CODE (t))
    {
    case INDIRECT_REF:
    case COMPONENT_REF:
      /* We assume that the object must be instantiated in order to build
	 the COMPONENT_REF, so we test only whether the type of the
	 COMPONENT_REF uses template parms.  */
      return uses_template_parms (TREE_TYPE (t));

    case IDENTIFIER_NODE:
      if (!IDENTIFIER_TEMPLATE (t))
	return 0;
      return uses_template_parms (TREE_VALUE (IDENTIFIER_TEMPLATE (t)));

      /* aggregates of tree nodes */
    case TREE_VEC:
      {
	int i = TREE_VEC_LENGTH (t);
	while (i--)
	  if (uses_template_parms (TREE_VEC_ELT (t, i)))
	    return 1;
	return 0;
      }
    case TREE_LIST:
      if (uses_template_parms (TREE_PURPOSE (t))
	  || uses_template_parms (TREE_VALUE (t)))
	return 1;
      return uses_template_parms (TREE_CHAIN (t));

      /* constructed type nodes */
    case POINTER_TYPE:
    case REFERENCE_TYPE:
      return uses_template_parms (TREE_TYPE (t));
    case RECORD_TYPE:
      if (TYPE_PTRMEMFUNC_FLAG (t))
	return uses_template_parms (TYPE_PTRMEMFUNC_FN_TYPE (t));
    case UNION_TYPE:
      if (!TYPE_NAME (t))
	return 0;
      if (!TYPE_IDENTIFIER (t))
	return 0;
      return uses_template_parms (TYPE_IDENTIFIER (t));
    case FUNCTION_TYPE:
      if (uses_template_parms (TYPE_ARG_TYPES (t)))
	return 1;
      return uses_template_parms (TREE_TYPE (t));
    case ARRAY_TYPE:
      if (uses_template_parms (TYPE_DOMAIN (t)))
	return 1;
      return uses_template_parms (TREE_TYPE (t));
    case OFFSET_TYPE:
      if (uses_template_parms (TYPE_OFFSET_BASETYPE (t)))
	return 1;
      return uses_template_parms (TREE_TYPE (t));
    case METHOD_TYPE:
      if (uses_template_parms (TYPE_METHOD_BASETYPE (t)))
	return 1;
      if (uses_template_parms (TYPE_ARG_TYPES (t)))
	return 1;
      return uses_template_parms (TREE_TYPE (t));

      /* decl nodes */
    case TYPE_DECL:
      return uses_template_parms (DECL_NAME (t));
    case FUNCTION_DECL:
      if (uses_template_parms (TREE_TYPE (t)))
	return 1;
      /* fall through */
    case VAR_DECL:
    case PARM_DECL:
      /* ??? What about FIELD_DECLs?  */
      /* The type of a decl can't use template parms if the name of the
	 variable doesn't, because it's impossible to resolve them.  So
	 ignore the type field for now.	 */
      if (DECL_CONTEXT (t) && uses_template_parms (DECL_CONTEXT (t)))
	return 1;
      if (uses_template_parms (TREE_TYPE (t)))
	{
	  error ("template parms used where they can't be resolved");
	}
      return 0;

    case CALL_EXPR:
      return uses_template_parms (TREE_TYPE (t));
    case ADDR_EXPR:
      return uses_template_parms (TREE_OPERAND (t, 0));

      /* template parm nodes */
    case TEMPLATE_TYPE_PARM:
    case TEMPLATE_CONST_PARM:
      return 1;

      /* simple type nodes */
    case INTEGER_TYPE:
      if (uses_template_parms (TYPE_MIN_VALUE (t)))
	return 1;
      return uses_template_parms (TYPE_MAX_VALUE (t));

    case REAL_TYPE:
    case VOID_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
      return 0;

      /* constants */
    case INTEGER_CST:
    case REAL_CST:
    case STRING_CST:
      return 0;

    case ERROR_MARK:
      /* Non-error_mark_node ERROR_MARKs are bad things.  */
      my_friendly_assert (t == error_mark_node, 274);
      /* NOTREACHED */
      return 0;

    case UNINSTANTIATED_P_TYPE:
      return 1;

    case CONSTRUCTOR:
      if (TREE_TYPE (t) && TYPE_PTRMEMFUNC_P (TREE_TYPE (t)))
	return uses_template_parms (TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (t)));
      /* else fall through */

    default:
      switch (TREE_CODE_CLASS (TREE_CODE (t)))
	{
	case '1':
	case '2':
	case '3':
	case '<':
	  {
	    int i;
	    for (i = tree_code_length[(int) TREE_CODE (t)]; --i >= 0;)
	      if (uses_template_parms (TREE_OPERAND (t, i)))
		return 1;
	    return 0;
	  }
	default:
	  break;
	}
      sorry ("testing %s for template parms",
	     tree_code_name [(int) TREE_CODE (t)]);
      my_friendly_abort (82);
      /* NOTREACHED */
      return 0;
    }
}

void
instantiate_member_templates (classname)
     tree classname;
{
  tree t;
  tree id = classname;
  tree members = DECL_TEMPLATE_MEMBERS (TREE_PURPOSE (IDENTIFIER_TEMPLATE (id)));

  for (t = members; t; t = TREE_CHAIN (t))
    {
      tree parmvec, type, classparms, tdecl, t2;
      int nparms, xxx = 0, i;

      my_friendly_assert (TREE_VALUE (t) != NULL_TREE, 275);
      my_friendly_assert (TREE_CODE (TREE_VALUE (t)) == TEMPLATE_DECL, 276);
      /* @@ Should verify that class parm list is a list of
	 distinct template parameters, and covers all the template
	 parameters.  */
      tdecl = TREE_VALUE (t);
      type = DECL_CONTEXT (DECL_TEMPLATE_RESULT (tdecl));
      classparms = UPT_PARMS (type);
      nparms = TREE_VEC_LENGTH (classparms);
      parmvec = make_tree_vec (nparms);
      for (i = 0; i < nparms; i++)
	TREE_VEC_ELT (parmvec, i) = NULL_TREE;
      switch (unify (DECL_TEMPLATE_PARMS (tdecl),
		     &TREE_VEC_ELT (parmvec, 0), nparms,
		     type, IDENTIFIER_TYPE_VALUE (classname),
		     &xxx))
	{
	case 0:
	  /* Success -- well, no inconsistency, at least.  */
	  for (i = 0; i < nparms; i++)
	    if (TREE_VEC_ELT (parmvec, i) == NULL_TREE)
	      goto failure;
	  t2 = instantiate_template (tdecl,
				     &TREE_VEC_ELT (parmvec, 0));
	  type = IDENTIFIER_TYPE_VALUE (id);
	  my_friendly_assert (type != 0, 277);
	  break;
	case 1:
	  /* Failure.  */
	failure:
	  cp_error_at ("type unification error instantiating `%D'", tdecl);
	  cp_error ("while instantiating members of `%T'", classname);

	  continue /* loop of members */;
	default:
	  /* Eek, a bug.  */
	  my_friendly_abort (83);
	}
    }
}

static struct tinst_level *current_tinst_level = 0;