diff options
Diffstat (limited to 'evaluate.c')
| -rw-r--r-- | evaluate.c | 47 |
1 files changed, 46 insertions, 1 deletions
@@ -2948,6 +2948,26 @@ static int cast_flags(struct expression *expr, struct expression *old) return flags; } +/// +// check if a type matches one of the members of a union type +// @utype: the union type +// @type: to type to check +// @return: to identifier of the matching type in the union. +static struct symbol *find_member_type(struct symbol *utype, struct symbol *type) +{ + struct symbol *t, *member; + + if (utype->type != SYM_UNION) + return NULL; + + FOR_EACH_PTR(utype->symbol_list, member) { + classify_type(member, &t); + if (type == t) + return member; + } END_FOR_EACH_PTR(member); + return NULL; +} + static struct symbol *evaluate_compound_literal(struct expression *expr, struct expression *source) { struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL); @@ -2973,6 +2993,7 @@ static struct symbol *evaluate_cast(struct expression *expr) struct expression *source = expr->cast_expression; struct symbol *ctype; struct symbol *ttype, *stype; + struct symbol *member; int tclass, sclass; struct ident *tas = NULL, *sas = NULL; @@ -3022,8 +3043,32 @@ static struct symbol *evaluate_cast(struct expression *expr) if (expr->type == EXPR_FORCE_CAST) goto out; - if (tclass & (TYPE_COMPOUND | TYPE_FN)) + if (tclass & (TYPE_COMPOUND | TYPE_FN)) { + /* + * Special case: cast to union type (GCC extension) + * The effect is similar to a compound literal except + * that the result is a rvalue. + */ + if ((member = find_member_type(ttype, stype))) { + struct expression *item, *init; + + if (Wunion_cast) + warning(expr->pos, "cast to union type"); + + item = alloc_expression(source->pos, EXPR_IDENTIFIER); + item->expr_ident = member->ident; + item->ident_expression = source; + + init = alloc_expression(source->pos, EXPR_INITIALIZER); + add_expression(&init->expr_list, item); + + // FIXME: this should be a rvalue + evaluate_compound_literal(expr, init); + return ctype; + } + warning(expr->pos, "cast to non-scalar"); + } if (sclass & TYPE_COMPOUND) warning(expr->pos, "cast from non-scalar"); |