decl2.c

gcc库的原代码,对编程有很大帮助.

  if (TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
    {
      /* Must add the class instance variable up front.  */
      /* Right now we just make this a pointer.  But later
	 we may wish to make it special.  */
      tree type = TREE_VALUE (arg_types);
      int constp = 1;

      if ((flag_this_is_variable > 0)
	  && (flags == DTOR_FLAG || DECL_CONSTRUCTOR_P (function)))
	constp = 0;

      if (DECL_CONSTRUCTOR_P (function))
	{
	  if (TYPE_USES_VIRTUAL_BASECLASSES (ctype))
	    {
	      DECL_CONSTRUCTOR_FOR_VBASE_P (function) = 1;
	      /* In this case we need "in-charge" flag saying whether
		 this constructor is responsible for initialization
		 of virtual baseclasses or not.  */
	      parm = build_decl (PARM_DECL, in_charge_identifier, integer_type_node);
	      /* Mark the artificial `__in_chrg' parameter as "artificial".  */
	      SET_DECL_ARTIFICIAL (parm);
	      DECL_ARG_TYPE (parm) = integer_type_node;
	      DECL_REGISTER (parm) = 1;
	      TREE_CHAIN (parm) = last_function_parms;
	      last_function_parms = parm;
	    }
	}

      parm = build_decl (PARM_DECL, this_identifier, type);
      /* Mark the artificial `this' parameter as "artificial".  */
      SET_DECL_ARTIFICIAL (parm);
      DECL_ARG_TYPE (parm) = type;
      /* We can make this a register, so long as we don't
	 accidentally complain if someone tries to take its address.  */
      DECL_REGISTER (parm) = 1;
      if (constp)
	TREE_READONLY (parm) = 1;
      TREE_CHAIN (parm) = last_function_parms;
      last_function_parms = parm;
    }

  if (flags == DTOR_FLAG)
    {
      char *buf, *dbuf;
      tree const_integer_type = build_type_variant (integer_type_node, 1, 0);
      int len = sizeof (DESTRUCTOR_DECL_PREFIX)-1;

      arg_types = hash_tree_chain (const_integer_type, void_list_node);
      TREE_SIDE_EFFECTS (arg_types) = 1;
      /* Build the overload name.  It will look like `7Example'.  */
      if (IDENTIFIER_TYPE_VALUE (cname))
	dbuf = build_overload_name (IDENTIFIER_TYPE_VALUE (cname), 1, 1);
      else if (IDENTIFIER_LOCAL_VALUE (cname))
	dbuf = build_overload_name (TREE_TYPE (IDENTIFIER_LOCAL_VALUE (cname)), 1, 1);
      else
      /* Using ctype fixes the `X::Y::~Y()' crash.  The cname has no type when
	 it's defined out of the class definition, since poplevel_class wipes
	 it out.  This used to be internal error 346.  */
	dbuf = build_overload_name (ctype, 1, 1);
      buf = (char *) alloca (strlen (dbuf) + sizeof (DESTRUCTOR_DECL_PREFIX));
      bcopy (DESTRUCTOR_DECL_PREFIX, buf, len);
      buf[len] = '\0';
      strcat (buf, dbuf);
      DECL_ASSEMBLER_NAME (function) = get_identifier (buf);
      parm = build_decl (PARM_DECL, in_charge_identifier, const_integer_type);
      /* Mark the artificial `__in_chrg' parameter as "artificial".  */
      SET_DECL_ARTIFICIAL (parm);
      TREE_USED (parm) = 1;
#if 0
      /* We don't need to mark the __in_chrg parameter itself as `const'
 	 since its type is already `const int'.  In fact we MUST NOT mark
 	 it as `const' cuz that will screw up the debug info (causing it
 	 to say that the type of __in_chrg is `const const int').  */
      TREE_READONLY (parm) = 1;
#endif
      DECL_ARG_TYPE (parm) = const_integer_type;
      /* This is the same chain as DECL_ARGUMENTS (...).  */
      TREE_CHAIN (last_function_parms) = parm;

      fntype = build_cplus_method_type (qualtype, void_type_node,
					arg_types);
      if (raises)
	{
	  fntype = build_exception_variant (fntype, raises);
	}
      TREE_TYPE (function) = fntype;
      TYPE_HAS_DESTRUCTOR (ctype) = 1;
    }
  else
    {
      tree these_arg_types;

      if (DECL_CONSTRUCTOR_FOR_VBASE_P (function))
	{
	  arg_types = hash_tree_chain (integer_type_node,
				       TREE_CHAIN (arg_types));
	  fntype = build_cplus_method_type (qualtype,
					    TREE_TYPE (TREE_TYPE (function)),
					    arg_types);
	  if (raises)
	    {
	      fntype = build_exception_variant (fntype, raises);
	    }
	  TREE_TYPE (function) = fntype;
	  arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
	}

      these_arg_types = arg_types;

      if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE)
	/* Only true for static member functions.  */
	these_arg_types = hash_tree_chain (build_pointer_type (qualtype),
					   arg_types);

      DECL_ASSEMBLER_NAME (function)
	= build_decl_overload (fn_name, these_arg_types,
			       1 + DECL_CONSTRUCTOR_P (function));

#if 0
      /* This code is going into the compiler, but currently, it makes
	 libg++/src/Integer.cc not compile.  The problem is that the nice name
	 winds up going into the symbol table, and conversion operations look
	 for the manged name.  */
      substitute_nice_name (function);
#endif
    }

  DECL_ARGUMENTS (function) = last_function_parms;
  /* First approximations.  */
  DECL_CONTEXT (function) = ctype;
  DECL_CLASS_CONTEXT (function) = ctype;
}

/* Work on the expr used by alignof (this is only called by the parser).  */
tree
grok_alignof (expr)
     tree expr;
{
  tree best, t;
  int bestalign;

  if (TREE_CODE (expr) == COMPONENT_REF
      && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
    error ("`__alignof__' applied to a bit-field");

  if (TREE_CODE (expr) == INDIRECT_REF)
    {
      best = t = TREE_OPERAND (expr, 0);
      bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));

      while (TREE_CODE (t) == NOP_EXPR
	     && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
	{
	  int thisalign;
	  t = TREE_OPERAND (t, 0);
	  thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
	  if (thisalign > bestalign)
	    best = t, bestalign = thisalign;
	}
      return c_alignof (TREE_TYPE (TREE_TYPE (best)));
    }
  else
    {
      /* ANSI says arrays and fns are converted inside comma.
	 But we can't convert them in build_compound_expr
	 because that would break commas in lvalues.
	 So do the conversion here if operand was a comma.  */
      if (TREE_CODE (expr) == COMPOUND_EXPR
	  && (TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE
	      || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE))
	expr = default_conversion (expr);
      return c_alignof (TREE_TYPE (expr));
    }
}

/* Create an ARRAY_REF, checking for the user doing things backwards
   along the way.  */
tree
grok_array_decl (array_expr, index_exp)
     tree array_expr, index_exp;
{
  tree type = TREE_TYPE (array_expr);
  tree p1, p2, i1, i2;

  if (type == error_mark_node || index_exp == error_mark_node)
    return error_mark_node;
  if (type == NULL_TREE)
    {
      /* Something has gone very wrong.  Assume we are mistakenly reducing
	 an expression instead of a declaration.  */
      error ("parser may be lost: is there a '{' missing somewhere?");
      return NULL_TREE;
    }

  if (TREE_CODE (type) == OFFSET_TYPE
      || TREE_CODE (type) == REFERENCE_TYPE)
    type = TREE_TYPE (type);

  /* If they have an `operator[]', use that.  */
  if (TYPE_LANG_SPECIFIC (type)
      && TYPE_OVERLOADS_ARRAY_REF (type))
    return build_opfncall (ARRAY_REF, LOOKUP_NORMAL,
			   array_expr, index_exp, NULL_TREE);

  /* Otherwise, create an ARRAY_REF for a pointer or array type.  */

  if (TREE_CODE (type) == ARRAY_TYPE)
    p1 = array_expr;
  else
    p1 = build_expr_type_conversion (WANT_POINTER, array_expr, 0);

  if (TREE_CODE (TREE_TYPE (index_exp)) == ARRAY_TYPE)
    p2 = index_exp;
  else
    p2 = build_expr_type_conversion (WANT_POINTER, index_exp, 0);

  i1 = build_expr_type_conversion (WANT_INT | WANT_ENUM, array_expr, 0);
  i2 = build_expr_type_conversion (WANT_INT | WANT_ENUM, index_exp, 0);

  if ((p1 && i2) && (i1 && p2))
    error ("ambiguous conversion for array subscript");

  if (p1 && i2)
    array_expr = p1, index_exp = i2;
  else if (i1 && p2)
    array_expr = p2, index_exp = i1;
  else
    {
      cp_error ("invalid types `%T[%T]' for array subscript",
		type, TREE_TYPE (index_exp));
      return error_mark_node;
    }

  if (array_expr == error_mark_node || index_exp == error_mark_node)
    error ("ambiguous conversion for array subscript");

  return build_array_ref (array_expr, index_exp);
}

/* Given the cast expression EXP, checking out its validity.   Either return
   an error_mark_node if there was an unavoidable error, return a cast to
   void for trying to delete a pointer w/ the value 0, or return the
   call to delete.  If DOING_VEC is 1, we handle things differently
   for doing an array delete.  If DOING_VEC is 2, they gave us the
   array size as an argument to delete.
   Implements ARM $5.3.4.  This is called from the parser.  */
tree
delete_sanity (exp, size, doing_vec, use_global_delete)
     tree exp, size;
     int doing_vec, use_global_delete;
{
  tree t = stabilize_reference (convert_from_reference (exp));
  tree type = TREE_TYPE (t);
  enum tree_code code = TREE_CODE (type);
  /* For a regular vector delete (aka, no size argument) we will pass
     this down as a NULL_TREE into build_vec_delete.  */
  tree maxindex = NULL_TREE;
  /* This is used for deleting arrays.  */
  tree elt_size;

  switch (doing_vec)
    {
    case 2:
      maxindex = build_binary_op (MINUS_EXPR, size, integer_one_node, 1);
      if (! flag_traditional)
	pedwarn ("anachronistic use of array size in vector delete");
      /* Fall through.  */
    case 1:
      elt_size = c_sizeof (type);
      break;
    default:
      if (code != POINTER_TYPE)
	{
	  cp_error ("type `%#T' argument given to `delete', expected pointer",
		    type);
	  return error_mark_node;
	}

      /* Deleting a pointer with the value zero is valid and has no effect.  */
      if (integer_zerop (t))
	return build1 (NOP_EXPR, void_type_node, t);
    }

  if (code == POINTER_TYPE)
    {
#if 0
      /* As of Valley Forge, you can delete a pointer to constant.  */
      /* You can't delete a pointer to constant.  */
      if (TREE_READONLY (TREE_TYPE (type)))
	{
	  error ("`const *' cannot be deleted");
	  return error_mark_node;
	}
#endif
      /* You also can't delete functions.  */
      if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
	{
	  error ("cannot delete a function");
	  return error_mark_node;
	}
    }

#if 0
  /* If the type has no destructor, then we should build a regular
     delete, instead of a vector delete.  Otherwise, we would end
     up passing a bogus offset into __builtin_delete, which is
     not expecting it.  */ 
  if (doing_vec
      && TREE_CODE (type) == POINTER_TYPE
      && !TYPE_HAS_DESTRUCTOR (TREE_TYPE (type)))
    {
      doing_vec = 0;
      use_global_delete = 1;
    }
#endif

  if (doing_vec)
    return build_vec_delete (t, maxindex, elt_size, integer_one_node,
			     integer_two_node, use_global_delete);
  else
    {
      if (IS_AGGR_TYPE (TREE_TYPE (type))
	  && TYPE_GETS_REG_DELETE (TREE_TYPE (type)))
	{
	  /* Only do access checking here; we'll be calling op delete
	     from the destructor.  */
	  tree tmp = build_opfncall (DELETE_EXPR, LOOKUP_NORMAL, t,
				     size_zero_node, NULL_TREE);
	  if (tmp == error_mark_node)
	    return error_mark_node;
	}

      return build_delete (type, t, integer_three_node,
			   LOOKUP_NORMAL|LOOKUP_HAS_IN_CHARGE,
			   use_global_delete);
    }
}

/* Sanity check: report error if this function FUNCTION is not
   really a member of the class (CTYPE) it is supposed to belong to.
   CNAME is the same here as it is for grokclassfn above.  */

tree
check_classfn (ctype, cname, function)
     tree ctype, cname, function;
{
  tree fn_name = DECL_NAME (function);
  tree fndecl;
  tree method_vec = CLASSTYPE_METHOD_VEC (ctype);
  tree *methods = 0;
  tree *end = 0;

  if (method_vec != 0)
    {
      methods = &TREE_VEC_ELT (method_vec, 0);
      end = TREE_VEC_END (method_vec);

      /* First suss out ctors and dtors.  */
      if (*methods && fn_name == DECL_NAME (*methods))
	goto got_it;

      while (++methods != end)
	{
	  if (fn_name == DECL_NAME (*methods))
	    {
	    got_it:
	      fndecl = *methods;
	      while (fndecl)
		{
		  if (DECL_ASSEMBLER_NAME (function) == DECL_ASSEMBLER_NAME (fndecl))
		    return fndecl;
#if 0
		  /* This should work, but causes libg++ to fail
		     make check-tFix. */
		  /* We have to do more extensive argument checking here, as
		     the name may have been changed by asm("new_name"). */
		  if (decls_match (function, fndecl))
		    return fndecl;
#else
		  if (DECL_NAME (function) == DECL_NAME (fndecl))
		    {
		      tree p1 = TYPE_ARG_TYPES (TREE_TYPE (function));
		      tree p2 = TYPE_ARG_TYPES (TREE_TYPE (fndecl));

		      /* Get rid of the this parameter on functions that become
			 static. */
		      if (DECL_STATIC_FUNCTION_P (fndecl)
			  && TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
			p1 = TREE_CHAIN (p1);

		      if (comptypes (TREE_TYPE (TREE_TYPE (function)),
				     TREE_TYPE (TREE_TYPE (fndecl)), 1)
			  && compparms (p1, p2, 3))
			{
			  if (DECL_STATIC_FUNCTION_P (fndecl)
			      && TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
			    revert_static_member_fn (&function, NULL, NULL);
			  return fndecl;
			}
		    }
#endif
		  fndecl = DECL_CHAIN (fndecl);
		}
	      break;		/* loser */
	    }
	}
    }

  if (methods != end)
    {
      tree fndecl = *methods;
      cp_error ("prototype for `%#D' does not match any in class `%T'",
		function, ctype);
      cp_error_at ("candidate%s: %+#D", DECL_CHAIN (fndecl) ? "s are" : " is",
		   fndecl);
      while (fndecl = DECL_CHAIN (fndecl), fndecl)
	cp_error_at ("                %#D", fndecl);
    }
  else
    {
      methods = 0;
      cp_error ("no `%#D' member function declared in class `%T'",
		function, ctype);
    }

  /* If we did not find the method in the class, add it to
     avoid spurious errors.  */
  add_method (ctype, methods, function);
  return NULL_TREE;
}

/* Process the specs, declarator (NULL if omitted) and width (NULL if omitted)
   of a structure component, returning a FIELD_DECL node.
   QUALS is a list of type qualifiers for this decl (such as for declaring
   const member functions).

   This is done during the parsing of the struct declaration.
   The FIELD_DECL nodes are chained together and the lot of them
   are ultimately passed to `build_struct' to make the RECORD_TYPE node.