Define char16_t, char32_t consistently with uint_least16_t, uint_least32_t (bug 17979)
Commit Message
As noted in bug 17979 (and as I noted earlier in
<https://sourceware.org/ml/libc-alpha/2012-02/msg00647.html>), uchar.h
has gratuitously complicated code to determine the types for char16_t
and char32_t, and to reject including that header for pre-C11
compilers not defining __CHAR16_TYPE__ and __CHAR32_TYPE__. Since
those types are always required to match uint_least16_t and
uint_least32_t, which glibc knows how to define without reference to
such predefined macros, it's safe just to define those types the same
as the *least* types are defined in stdint.h, so allowing the header
to work with (for example) GCC 4.3.
This patch implements that. bits/types.h is made to define
__int_leastN_t and __uint_leastN_t so the logic for those types can
stay in a single place, and stdint.h is made to use those __*_t to
define the public *_t types. uchar.h is then made to use
__uint_least16_t and __uint_least32_t to define char16_t and char32_t,
so simplifying the logic there. A new test is added that verifies the
types chosen for char16_t and char32_t do indeed match the types the
compiler uses for u"" and U"" string literals.
Tested for x86_64. (I have not tested with any of the older compilers
for which this would actually make a difference to whether you can
include uchar.h.)
2018-02-01 Joseph Myers <joseph@codesourcery.com>
[BZ #17979]
* posix/bits/types.h (__int_least8_t): New typedef.
(__uint_least8_t): Likewise.
(__int_least16_t): Likewise.
(__uint_least16_t): Likewise.
(__int_least32_t): Likewise.
(__uint_least32_t): Likewise.
(__int_least64_t): Likewise.
(__uint_least64_t): Likewise.
* sysdeps/generic/stdint.h (int_least8_t): Define using
__int_least8_t.
(int_least16_t): Define using __int_least16_t.
(int_least32_t): Define using __int_least32_t.
(int_least64_t): Define using __int_least64_t.
(uint_least8_t): Define using __uint_least8_t.
(uint_least16_t): Define using __uint_least16_t.
(uint_least32_t): Define using __uint_least32_t.
(uint_least64_t): Define using __uint_least64_t.
* wcsmbs/uchar.h: Include <bits/types.h>.
(char16_t): Define using __uint_least16_t conditional only on
[!__USE_ISOCXX11].
(char32_t): Define using __uint_least32_t conditional only on
[!__USE_ISOCXX11].
* wcsmbs/test-char-types.c: New file.
* wcsmbs/Makefile (tests): Add test-char-types.
Comments
Ping. This patch
<https://sourceware.org/ml/libc-alpha/2018-02/msg00032.html> is pending
review.
On 01/02/2018 18:36, Joseph Myers wrote:
> As noted in bug 17979 (and as I noted earlier in
> <https://sourceware.org/ml/libc-alpha/2012-02/msg00647.html>), uchar.h
> has gratuitously complicated code to determine the types for char16_t
> and char32_t, and to reject including that header for pre-C11
> compilers not defining __CHAR16_TYPE__ and __CHAR32_TYPE__. Since
> those types are always required to match uint_least16_t and
> uint_least32_t, which glibc knows how to define without reference to
> such predefined macros, it's safe just to define those types the same
> as the *least* types are defined in stdint.h, so allowing the header
> to work with (for example) GCC 4.3.
>
> This patch implements that. bits/types.h is made to define
> __int_leastN_t and __uint_leastN_t so the logic for those types can
> stay in a single place, and stdint.h is made to use those __*_t to
> define the public *_t types. uchar.h is then made to use
> __uint_least16_t and __uint_least32_t to define char16_t and char32_t,
> so simplifying the logic there. A new test is added that verifies the
> types chosen for char16_t and char32_t do indeed match the types the
> compiler uses for u"" and U"" string literals.
>
> Tested for x86_64. (I have not tested with any of the older compilers
> for which this would actually make a difference to whether you can
> include uchar.h.)
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> +
> +#include <uchar.h>
> +
> +const char16_t *s16 = u"";
> +const char32_t *s32 = U"";
> +
> +static int
> +do_test (void)
> +{
> + /* This is a compilation test. */
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
Maybe we could add these kind of tests on build time to catch on cross-compilation,
as:
#define is_compatible(x, T) _Generic((x), T:1, default: 0)
#define check_compatibility(x, t) \
_Static_assert (is_compatible (x, t), "type not compatible")
check_compatibility (u"", char16_t *);
check_compatibility (U"", char32_t *);
On Wed, 7 Feb 2018, Adhemerval Zanella wrote:
> > +#include <uchar.h>
> > +
> > +const char16_t *s16 = u"";
> > +const char32_t *s32 = U"";
> > +
> > +static int
> > +do_test (void)
> > +{
> > + /* This is a compilation test. */
> > + return 0;
> > +}
> > +
> > +#include <support/test-driver.c>
>
> Maybe we could add these kind of tests on build time to catch on
> cross-compilation, as:
The test above is fully functional for cross compilation (provided you
compile the testsuite, not just glibc itself, of course).
> #define is_compatible(x, T) _Generic((x), T:1, default: 0)
> #define check_compatibility(x, t) \
> _Static_assert (is_compatible (x, t), "type not compatible")
>
> check_compatibility (u"", char16_t *);
> check_compatibility (U"", char32_t *);
This would be problematic because of -Wwrite-strings meaning the types end
up as const char16_t * and const char32_t *. The test as written works
whether or not the type ends up being const-qualified. (You don't want a
test that actually relies on -Wwrite-strings being in use to get the
tested-for type, because it's not ideal that -Wwrite-strings works by
changing types of string constants; see GCC bug 61579.)
On 07/02/2018 18:30, Joseph Myers wrote:
> On Wed, 7 Feb 2018, Adhemerval Zanella wrote:
>
>>> +#include <uchar.h>
>>> +
>>> +const char16_t *s16 = u"";
>>> +const char32_t *s32 = U"";
>>> +
>>> +static int
>>> +do_test (void)
>>> +{
>>> + /* This is a compilation test. */
>>> + return 0;
>>> +}
>>> +
>>> +#include <support/test-driver.c>
>>
>> Maybe we could add these kind of tests on build time to catch on
>> cross-compilation, as:
>
> The test above is fully functional for cross compilation (provided you
> compile the testsuite, not just glibc itself, of course).
>
>> #define is_compatible(x, T) _Generic((x), T:1, default: 0)
>> #define check_compatibility(x, t) \
>> _Static_assert (is_compatible (x, t), "type not compatible")
>>
>> check_compatibility (u"", char16_t *);
>> check_compatibility (U"", char32_t *);
>
> This would be problematic because of -Wwrite-strings meaning the types end
> up as const char16_t * and const char32_t *. The test as written works
> whether or not the type ends up being const-qualified. (You don't want a
> test that actually relies on -Wwrite-strings being in use to get the
> tested-for type, because it's not ideal that -Wwrite-strings works by
> changing types of string constants; see GCC bug 61579.)
>
Fair enough.
@@ -47,6 +47,16 @@ __extension__ typedef signed long long int __int64_t;
__extension__ typedef unsigned long long int __uint64_t;
#endif
+/* Smallest types with at least a given width. */
+typedef __int8_t __int_least8_t;
+typedef __uint8_t __uint_least8_t;
+typedef __int16_t __int_least16_t;
+typedef __uint16_t __uint_least16_t;
+typedef __int32_t __int_least32_t;
+typedef __uint32_t __uint_least32_t;
+typedef __int64_t __int_least64_t;
+typedef __uint64_t __uint_least64_t;
+
/* quad_t is also 64 bits. */
#if __WORDSIZE == 64
typedef long int __quad_t;
@@ -40,26 +40,16 @@
/* Small types. */
/* Signed. */
-typedef signed char int_least8_t;
-typedef short int int_least16_t;
-typedef int int_least32_t;
-#if __WORDSIZE == 64
-typedef long int int_least64_t;
-#else
-__extension__
-typedef long long int int_least64_t;
-#endif
+typedef __int_least8_t int_least8_t;
+typedef __int_least16_t int_least16_t;
+typedef __int_least32_t int_least32_t;
+typedef __int_least64_t int_least64_t;
/* Unsigned. */
-typedef unsigned char uint_least8_t;
-typedef unsigned short int uint_least16_t;
-typedef unsigned int uint_least32_t;
-#if __WORDSIZE == 64
-typedef unsigned long int uint_least64_t;
-#else
-__extension__
-typedef unsigned long long int uint_least64_t;
-#endif
+typedef __uint_least8_t uint_least8_t;
+typedef __uint_least16_t uint_least16_t;
+typedef __uint_least32_t uint_least32_t;
+typedef __uint_least64_t uint_least64_t;
/* Fast types. */
@@ -50,7 +50,7 @@ strop-tests := wcscmp wcsncmp wmemcmp wcslen wcschr wcsrchr wcscpy wcsnlen \
tests := tst-wcstof wcsmbs-tst1 tst-wcsnlen tst-btowc tst-mbrtowc \
tst-wcrtomb tst-wcpncpy tst-mbsrtowcs tst-wchar-h tst-mbrtowc2 \
tst-c16c32-1 wcsatcliff tst-wcstol-locale tst-wcstod-nan-locale \
- tst-wcstod-round \
+ tst-wcstod-round test-char-types \
$(addprefix test-,$(strop-tests))
include ../Rules
new file mode 100644
@@ -0,0 +1,31 @@
+/* Test char16_t and char32_t types consistent with compiler.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <uchar.h>
+
+const char16_t *s16 = u"";
+const char32_t *s32 = U"";
+
+static int
+do_test (void)
+{
+ /* This is a compilation test. */
+ return 0;
+}
+
+#include <support/test-driver.c>
@@ -28,20 +28,13 @@
#define __need_size_t
#include <stddef.h>
+#include <bits/types.h>
#include <bits/types/mbstate_t.h>
-#if defined __GNUC__ && !defined __USE_ISOCXX11
-/* Define the 16-bit and 32-bit character types. Use the information
- provided by the compiler. */
-# if !defined __CHAR16_TYPE__ || !defined __CHAR32_TYPE__
-# if defined __STDC_VERSION__ && __STDC_VERSION__ < 201000L
-# error "<uchar.h> requires ISO C11 mode"
-# else
-# error "definitions of __CHAR16_TYPE__ and/or __CHAR32_TYPE__ missing"
-# endif
-# endif
-typedef __CHAR16_TYPE__ char16_t;
-typedef __CHAR32_TYPE__ char32_t;
+#ifndef __USE_ISOCXX11
+/* Define the 16-bit and 32-bit character types. */
+typedef __uint_least16_t char16_t;
+typedef __uint_least32_t char32_t;
#endif