On 11/5/18 2:39 PM, Tom Honermann wrote:
This patch adds support for the P0482R5 core language changes. This
includes:
- The -fchar8_t and -fno_char8_t command line options.
- char8_t as a keyword.
- The char8_t builtin type as a non-aliasing unsigned integral
character type of size 1.
- Use of char8_t as a simple type specifier.
- u8 character literals with type char8_t.
- u8 string literals with type array of const char8_t.
- User defined literal operators that accept char8_1 and char8_t pointer
types.
- New __cpp_char8_t predefined feature test macro.
- New __CHAR8_TYPE__ and __GCC_ATOMIC_CHAR8_T_LOCK_FREE predefined
macros .
- Name mangling and demangling for char8_t (using Du).
gcc/ChangeLog:
2018-11-04 Tom Honermann <tom@honermann.net>
* defaults.h: Define CHAR8_TYPE.
gcc/c-family/ChangeLog:
2018-11-04 Tom Honermann <tom@honermann.net>
* c-family/c-common.c (c_common_reswords): Add char8_t.
(fix_string_type): Use char8_t for the type of u8 string literals.
(c_common_get_alias_set): char8_t doesn't alias.
(c_common_nodes_and_builtins): Define char8_t as a builtin type in
C++.
(c_stddef_cpp_builtins): Add __CHAR8_TYPE__.
(keyword_begins_type_specifier): Add RID_CHAR8.
* gcc/c-family/c-common.h (rid): Add RID_CHAR8.
(c_tree_index): Add CTI_CHAR8_TYPE and CTI_CHAR8_ARRAY_TYPE.
Define D_CXX_CHAR8_T and D_CXX_CHAR8_T_FLAGS.
Define char8_type_node and char8_array_type_node.
* c-family/c-cppbuiltin.c (cpp_atomic_builtins): Predefine
__GCC_ATOMIC_CHAR8_T_LOCK_FREE.
(c_cpp_builtins): Predefine __cpp_char8_t.
* c-family/c-lex.c (lex_string): Use char8_array_type_node as the
type of CPP_UTF8STRING.
(lex_charconst): Use char8_type_node as the type of CPP_UTF8CHAR.
* c-family/c.opt: Add the -fchar8_t command line option.
gcc/c/ChangeLog:
2018-11-04 Tom Honermann <tom@honermann.net>
* c/c-typeck.c (char_type_p): Add char8_type_node.
(digest_init): Handle initialization by a u8 string literal of
char8_t type.
gcc/cp/ChangeLog:
2018-11-04 Tom Honermann <tom@honermann.net>
* cp/cvt.c (type_promotes_to): Handle char8_t promotion.
* cp/decl.c (grokdeclarator): Handle invalid type specifier
combinations involving char8_t.
* cp/lex.c (init_reswords): Add char8_t as a reserved word.
* cp/mangle.c (write_builtin_type): Add name mangling for char8_t
(Du).
* cp/parser.c (cp_keyword_starts_decl_specifier_p,
cp_parser_simple_type_specifier): Recognize char8_t as a simple
type specifier.
(cp_parser_string_literal): Use char8_array_type_node for the type
of CPP_UTF8STRING.
(cp_parser_set_decl_spec_type): Tolerate char8_t typedefs in system
headers.
* cp/rtti.c (emit_support_tinfos): type_info support for char8_t.
* cp/tree.c (char_type_p): Recognize char8_t as a character type.
* cp/typeck.c (string_conv_p): Handle conversions of u8 string
literals of char8_t type.
(check_literal_operator_args): Handle UDLs with u8 string literals
of char8_t type.
* cp/typeck2.c (digest_init_r): Disallow initializing a char array
with a u8 string literal.
libiberty/ChangeLog:
2018-10-31 Tom Honermann <tom@honermann.net>
* cp-demangle.c (cplus_demangle_builtin_types,
cplus_demangle_type): Add name demangling for char8_t (Du).
* cp-demangle.h: Increase D_BUILTIN_TYPE_COUNT to accommodate the
new char8_t type.
@@ -3543,6 +3556,10 @@ c_common_get_alias_set (tree t)
if (!TYPE_P (t))
return -1;
+ /* Unlike char, char8_t doesn't alias. */
+ if (flag_char8_t && t == char8_type_node)
+ return -1;
This seems unnecessary; doesn't the existing code have the same effect?
I think we could do with just an adjustment to the existing comment.
+ else if (flag_char8_t && TREE_TYPE (value) == char8_array_type_node)
+ || (flag_char8_t && type == char8_type_node)
+ bool char8_array = (flag_char8_t && !!comptypes (typ1,
char8_type_node));
+ || (flag_char8_t && type == char8_type_node
In many places you check the flag and then for one of the char8 types.
Since the types won't be used without the flag, checking the flag seems
redundant?
- if (TYPE_PRECISION (typ1) == BITS_PER_UNIT)
+ if (TYPE_PRECISION (typ1) == BITS_PER_UNIT
+ && (typ1 == char_type_node || !flag_char8_t))
This looks wrong, or at least incomplete; we want to complain about
mismatched types here even with -fchar8-t. Perhaps we should replace
all of this if/else with simply comparing typ1 and char_type, and
complaining if they're different. Talking about wide and non-wide isn't
as useful as the actual types would be.