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b34b46b880
C23 adds a header <stdbit.h> with various functions and type-generic
macros for bit-manipulation of unsigned integers (plus macro defines
related to endianness). Implement this header for glibc.
The functions have both inline definitions in the header (referenced
by macros defined in the header) and copies with external linkage in
the library (which are implemented in terms of those macros to avoid
duplication). They are documented in the glibc manual. Tests, as
well as verifying results for various inputs (of both the macros and
the out-of-line functions), verify the types of those results (which
showed up a bug in an earlier version with the type-generic macro
stdc_has_single_bit wrongly returning a promoted type), that the
macros can be used at top level in a source file (so don't use ({})),
that they evaluate their arguments exactly once, and that the macros
for the type-specific functions have the expected implicit conversions
to the relevant argument type.
Jakub previously referred to -Wconversion warnings in type-generic
macros, so I've included a test with -Wconversion (but the only
warnings I saw and fixed from that test were actually in inline
functions in the <stdbit.h> header - not anything coming from use of
the type-generic macros themselves).
This implementation of the type-generic macros does not handle
unsigned __int128, or unsigned _BitInt types with a width other than
that of a standard integer type (and C23 doesn't require the header to
handle such types either). Support for those types, using the new
type-generic built-in functions Jakub's added for GCC 14, can
reasonably be added in a followup (along of course with associated
tests).
This implementation doesn't do anything special to handle C++, or have
any tests of functionality in C++ beyond the existing tests that all
headers can be compiled in C++ code; it's not clear exactly what form
this header should take in C++, but probably not one using macros.
DIS ballot comment AT-107 asks for the word "count" to be added to the
names of the stdc_leading_zeros, stdc_leading_ones,
stdc_trailing_zeros and stdc_trailing_ones functions and macros. I
don't think it's likely to be accepted (accepting any technical
comments would mean having an FDIS ballot), but if it is accepted at
the WG14 meeting (22-26 January in Strasbourg, starting with DIS
ballot comment handling) then there would still be time to update
glibc for the renaming before the 2.39 release.
The new functions and header are placed in the stdlib/ directory in
glibc, rather than creating a new toplevel stdbit/ or putting them in
string/ alongside ffs.
Tested for x86_64 and x86.
199 lines
8.0 KiB
C
199 lines
8.0 KiB
C
/* Common test support for <stdbit.h> tests.
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Copyright (C) 2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _TST_STDBIT_H
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#define _TST_STDBIT_H
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#include <stdbit.h>
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#include <stdbool.h>
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#include <array_length.h>
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#include <support/check.h>
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struct stdbit_test
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{
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/* The test input. */
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uint64_t x;
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/* Expected results if that test input is converted to 8, 16, 32 or
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64 bits and then passed to the function under test for that
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width. */
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uint64_t res_8, res_16, res_32, res_64;
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};
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#define TEST_TYPE(EXPR, TYPE) \
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_Static_assert (_Generic ((EXPR), TYPE: 1, default: 0), "bad type")
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/* Test a <stdbit.h> function / macro. For each function family, and
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each input type, we test both with and without macros from the
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header being used, both with a possibly wider argument being passed
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(that must be truncated by the prototype) and with the argument
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truncated in the caller, as well as testing the type-generic macro
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(with the argument truncated in the caller). Also test that the
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results have the correct type; also test truncation from
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floating-point arguments (valid for functions, including with macro
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expansion, because the prototype must implicitly convert to integer
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type; not valid for the type-generic macros). Also test that the
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argument is evaluated exactly once. Also test the macros are
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usable (e.g. in typeof) at top level (GCC doesn't allow ({})
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outside functions: bug 93239). */
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#define TEST_STDBIT_T(FUNC, X, RES, TTYPE, TYPE, SUFFIX) \
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do \
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{ \
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TEST_COMPARE (FUNC ## SUFFIX (X), (RES)); \
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TEST_TYPE (FUNC ## SUFFIX (X), TTYPE); \
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TEST_COMPARE ((FUNC ## SUFFIX) (X), (RES)); \
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TEST_TYPE ((FUNC ## SUFFIX) (X), TTYPE); \
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TEST_COMPARE (FUNC ## SUFFIX ((TYPE) (X)), (RES)); \
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TEST_TYPE (FUNC ## SUFFIX ((TYPE) (X)), TTYPE); \
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TEST_COMPARE ((FUNC ## SUFFIX) ((TYPE) (X)), (RES)); \
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TEST_TYPE ((FUNC ## SUFFIX) ((TYPE) (X)), TTYPE); \
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TEST_COMPARE (FUNC ((TYPE) (X)), (RES)); \
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TEST_TYPE (FUNC ((TYPE) (X)), TTYPE); \
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if (sizeof (TYPE) <= 2) \
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{ \
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TEST_COMPARE (FUNC ## SUFFIX ((float) (TYPE) (X)), (RES)); \
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TEST_TYPE (FUNC ## SUFFIX ((float) (TYPE) (X)), TTYPE); \
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TEST_COMPARE ((FUNC ## SUFFIX) ((float) (TYPE) (X)), (RES)); \
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TEST_TYPE ((FUNC ## SUFFIX) ((float) (TYPE) (X)), TTYPE); \
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} \
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if (sizeof (TYPE) <= 4) \
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{ \
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TEST_COMPARE (FUNC ## SUFFIX ((double) (TYPE) (X)), (RES)); \
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TEST_TYPE (FUNC ## SUFFIX ((double) (TYPE) (X)), TTYPE); \
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TEST_COMPARE ((FUNC ## SUFFIX) ((double) (TYPE) (X)), (RES)); \
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TEST_TYPE ((FUNC ## SUFFIX) ((double) (TYPE) (X)), TTYPE); \
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TEST_COMPARE (FUNC ## SUFFIX ((long double) (TYPE) (X)), (RES)); \
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TEST_TYPE (FUNC ## SUFFIX ((long double) (TYPE) (X)), TTYPE); \
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TEST_COMPARE ((FUNC ## SUFFIX) ((long double) (TYPE) (X)), (RES)); \
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TEST_TYPE ((FUNC ## SUFFIX) ((long double) (TYPE) (X)), TTYPE); \
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} \
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TYPE xt = (X); \
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TEST_COMPARE (FUNC ## SUFFIX (xt++), (RES)); \
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TEST_COMPARE (xt, (TYPE) ((X) + 1)); \
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xt = (X); \
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TEST_COMPARE (FUNC (xt++), (RES)); \
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TEST_COMPARE (xt, (TYPE) ((X) + 1)); \
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} \
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while (0)
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#define TEST_STDBIT_UI(FUNC, INPUTS) \
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do \
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for (int i = 0; i < array_length (INPUTS); i++) \
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{ \
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uint64_t x = (INPUTS)[i].x; \
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unsigned int res_8 = (INPUTS)[i].res_8; \
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unsigned int res_16 = (INPUTS)[i].res_16; \
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unsigned int res_32 = (INPUTS)[i].res_32; \
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unsigned int res_64 = (INPUTS)[i].res_64; \
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unsigned int res_l = (sizeof (long int) == 4 \
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? res_32 : res_64); \
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TEST_STDBIT_T (FUNC, x, res_8, unsigned int, \
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unsigned char, _uc); \
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TEST_STDBIT_T (FUNC, x, res_16, unsigned int, \
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unsigned short, _us); \
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TEST_STDBIT_T (FUNC, x, res_32, unsigned int, \
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unsigned int, _ui); \
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TEST_STDBIT_T (FUNC, x, res_l, unsigned int, \
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unsigned long int, _ul); \
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TEST_STDBIT_T (FUNC, x, res_64, unsigned int, \
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unsigned long long int, _ull); \
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} \
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while (0)
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#define TEST_STDBIT_BOOL(FUNC, INPUTS) \
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do \
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for (int i = 0; i < array_length (INPUTS); i++) \
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{ \
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uint64_t x = (INPUTS)[i].x; \
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bool res_8 = (INPUTS)[i].res_8; \
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bool res_16 = (INPUTS)[i].res_16; \
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bool res_32 = (INPUTS)[i].res_32; \
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bool res_64 = (INPUTS)[i].res_64; \
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bool res_l = (sizeof (long int) == 4 ? res_32 : res_64); \
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TEST_STDBIT_T (FUNC, x, res_8, _Bool, unsigned char, _uc); \
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TEST_STDBIT_T (FUNC, x, res_16, _Bool, unsigned short, _us); \
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TEST_STDBIT_T (FUNC, x, res_32, _Bool, unsigned int, _ui); \
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TEST_STDBIT_T (FUNC, x, res_l, _Bool, unsigned long int, _ul); \
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TEST_STDBIT_T (FUNC, x, res_64, _Bool, \
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unsigned long long int, _ull); \
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} \
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while (0)
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#define TEST_STDBIT_SAME(FUNC, INPUTS) \
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do \
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for (int i = 0; i < array_length (INPUTS); i++) \
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{ \
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uint64_t x = (INPUTS)[i].x; \
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unsigned char res_8 = (INPUTS)[i].res_8; \
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unsigned short res_16 = (INPUTS)[i].res_16; \
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unsigned int res_32 = (INPUTS)[i].res_32; \
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unsigned long long int res_64 = (INPUTS)[i].res_64; \
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unsigned long int res_l = (sizeof (long int) == 4 \
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? res_32 : res_64); \
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TEST_STDBIT_T (FUNC, x, res_8, unsigned char, \
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unsigned char, _uc); \
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TEST_STDBIT_T (FUNC, x, res_16, unsigned short, \
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unsigned short, _us); \
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TEST_STDBIT_T (FUNC, x, res_32, unsigned int, \
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unsigned int, _ui); \
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TEST_STDBIT_T (FUNC, x, res_l, unsigned long int, \
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unsigned long int, _ul); \
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TEST_STDBIT_T (FUNC, x, res_64, unsigned long long int, \
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unsigned long long int, _ull); \
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} \
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while (0)
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#define TEST_STDBIT_UI_TOPLEVEL(FUNC) \
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TEST_TYPE (FUNC ## _uc ((unsigned char) 0), unsigned int); \
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TEST_TYPE (FUNC ((unsigned char) 0), unsigned int); \
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TEST_TYPE (FUNC ## _us ((unsigned short) 0), unsigned int); \
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TEST_TYPE (FUNC ((unsigned short) 0), unsigned int); \
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TEST_TYPE (FUNC ## _ui (0U), unsigned int); \
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TEST_TYPE (FUNC (0U), unsigned int); \
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TEST_TYPE (FUNC ## _ul (0UL), unsigned int); \
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TEST_TYPE (FUNC (0UL), unsigned int); \
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TEST_TYPE (FUNC ## _ull (0ULL), unsigned int); \
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TEST_TYPE (FUNC (0ULL), unsigned int)
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#define TEST_STDBIT_BOOL_TOPLEVEL(FUNC) \
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TEST_TYPE (FUNC ## _uc ((unsigned char) 0), _Bool); \
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TEST_TYPE (FUNC ((unsigned char) 0), _Bool); \
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TEST_TYPE (FUNC ## _us ((unsigned short) 0), _Bool); \
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TEST_TYPE (FUNC ((unsigned short) 0), _Bool); \
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TEST_TYPE (FUNC ## _ui (0U), _Bool); \
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TEST_TYPE (FUNC (0U), _Bool); \
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TEST_TYPE (FUNC ## _ul (0UL), _Bool); \
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TEST_TYPE (FUNC (0UL), _Bool); \
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TEST_TYPE (FUNC ## _ull (0ULL), _Bool); \
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TEST_TYPE (FUNC (0ULL), _Bool)
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#define TEST_STDBIT_SAME_TOPLEVEL(FUNC) \
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TEST_TYPE (FUNC ## _uc ((unsigned char) 0), unsigned char); \
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TEST_TYPE (FUNC ((unsigned char) 0), unsigned char); \
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TEST_TYPE (FUNC ## _us ((unsigned short) 0), unsigned short); \
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TEST_TYPE (FUNC ((unsigned short) 0), unsigned short); \
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TEST_TYPE (FUNC ## _ui (0U), unsigned int); \
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TEST_TYPE (FUNC (0U), unsigned int); \
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TEST_TYPE (FUNC ## _ul (0UL), unsigned long int); \
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TEST_TYPE (FUNC (0UL), unsigned long int); \
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TEST_TYPE (FUNC ## _ull (0ULL), unsigned long long int); \
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TEST_TYPE (FUNC (0ULL), unsigned long long int)
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#endif
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