+/* Perform default promotions for C data used in expressions.
+ Arrays and functions are converted to pointers;
+ enumeral types or short or char, to int.
+ In addition, manifest constants symbols are replaced by their values. */
+
+tree
+default_conversion (exp)
+ tree exp;
+{
+ tree orig_exp;
+ tree type = TREE_TYPE (exp);
+ enum tree_code code = TREE_CODE (type);
+
+ if (code == FUNCTION_TYPE || code == ARRAY_TYPE)
+ return default_function_array_conversion (exp);
+
+ /* Constants can be used directly unless they're not loadable. */
+ if (TREE_CODE (exp) == CONST_DECL)
+ exp = DECL_INITIAL (exp);
+
+ /* Replace a nonvolatile const static variable with its value unless
+ it is an array, in which case we must be sure that taking the
+ address of the array produces consistent results. */
+ else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
+ {
+ exp = decl_constant_value_for_broken_optimization (exp);
+ type = TREE_TYPE (exp);
+ }
+
+ /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
+ an lvalue.
+
+ Do not use STRIP_NOPS here! It will remove conversions from pointer
+ to integer and cause infinite recursion. */
+ orig_exp = exp;
+ while (TREE_CODE (exp) == NON_LVALUE_EXPR
+ || (TREE_CODE (exp) == NOP_EXPR
+ && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
+ exp = TREE_OPERAND (exp, 0);
+
+ /* Preserve the original expression code. */
+ if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (exp))))
+ C_SET_EXP_ORIGINAL_CODE (exp, C_EXP_ORIGINAL_CODE (orig_exp));
+
+ /* Normally convert enums to int,
+ but convert wide enums to something wider. */
+ if (code == ENUMERAL_TYPE)
+ {
+ type = type_for_size (MAX (TYPE_PRECISION (type),
+ TYPE_PRECISION (integer_type_node)),
+ ((flag_traditional
+ || (TYPE_PRECISION (type)
+ >= TYPE_PRECISION (integer_type_node)))
+ && TREE_UNSIGNED (type)));
+
+ return convert (type, exp);
+ }
+
+ if (TREE_CODE (exp) == COMPONENT_REF
+ && DECL_C_BIT_FIELD (TREE_OPERAND (exp, 1))
+ /* If it's thinner than an int, promote it like a
+ c_promoting_integer_type_p, otherwise leave it alone. */
+ && 0 > compare_tree_int (DECL_SIZE (TREE_OPERAND (exp, 1)),
+ TYPE_PRECISION (integer_type_node)))
+ return convert (flag_traditional && TREE_UNSIGNED (type)
+ ? unsigned_type_node : integer_type_node,
+ exp);
+
+ if (c_promoting_integer_type_p (type))
+ {
+ /* Traditionally, unsignedness is preserved in default promotions.
+ Also preserve unsignedness if not really getting any wider. */
+ if (TREE_UNSIGNED (type)
+ && (flag_traditional
+ || TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
+ return convert (unsigned_type_node, exp);
+
+ return convert (integer_type_node, exp);
+ }
+
+ if (flag_traditional && !flag_allow_single_precision
+ && TYPE_MAIN_VARIANT (type) == float_type_node)
+ return convert (double_type_node, exp);
+
+ if (code == VOID_TYPE)
+ {
+ error ("void value not ignored as it ought to be");
+ return error_mark_node;
+ }
+ return exp;
+}
+\f
+/* Look up COMPONENT in a structure or union DECL.
+
+ If the component name is not found, returns NULL_TREE. Otherwise,
+ the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
+ stepping down the chain to the component, which is in the last
+ TREE_VALUE of the list. Normally the list is of length one, but if
+ the component is embedded within (nested) anonymous structures or
+ unions, the list steps down the chain to the component. */