4 Commits

Author	SHA1	Message	Date
Joseph Myers	d614a75396	Update copyright dates with scripts/update-copyrights.	2020-01-01 00:14:33 +00:00
Paul Eggert	5a82c74822	Prefer https to http for gnu.org and fsf.org URLs ... Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S	2019-09-07 02:43:31 -07:00
Joseph Myers	04277e02d7	Update copyright dates with scripts/update-copyrights. ... * All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.	2019-01-01 00:11:28 +00:00
Joseph Myers	0d40d0ecba	Unify and simplify bits/byteswap.h, bits/byteswap-16.h headers (bug 14508, bug 15512, bug 17082, bug 20530). ... We have a general principle of preferring optimizations for library facilities to use compiler built-in functions rather than being located in library headers, where the compiler can reasonably optimize code without needing to know glibc implementation details. This patch applies this principle to bits/byteswap.h, eliminating all the architecture-specific variants and bits/byteswap-16.h. The __bswap_16, __bswap_32 and __bswap_64 interfaces all become inline functions, never macros, using the GCC built-in functions where available and otherwise a single architecture-independent definition using shifts and masking (which compilers may well be able to detect and optimize; GCC has detection of various byte-swapping idioms). The __bswap_constant_32 macro needs to stay around because of uses in static initializers within glibc and its tests, and so for consistency all __bswap_constant_* are kept rather than just being inlined into the old-GCC-or-non-GCC parts of the __bswap_* inline function definitions. Various open bugs are addressed by this cleanup, with caveats about exactly what is covered by those bugs and when the bugs applied at all. Bug 14508 reports -Wformat warnings building glibc because __bswap_* sometimes returned the wrong types. Obviously we already don't have such warnings any more or the build would be failing, given -Werror, and I suspect that bug was originally for wrong types for x86_64, as fixed by commit d394eb742a (glibc 2.17). The only case I saw removed by this patch where the types would still have been wrong was the non-__GNUC__ case of __bswap_64 in the s390 header (using unsigned long long int, but uint64_t would be unsigned long int for 64-bit). In any case, the single header consistently uses __uintN_t types after this patch, thereby eliminating all such bugs. The existing string/test-endian-types.c test already suffices to verify that the types are correct with the compiler used to build glibc and its tests. Bug 15512 reports an error from __bswap_constant_16 with -Werror -Wsign-conversion. I am unable to reproduce this with any GCC version supporting -Wsign-conversion - all seem to be able to avoid warning for ((x) >> 8) & 0xffu, where x is uint16_t, which while it formally does involve an implicit conversion from int to unsigned int, is also a case where it should be easy for the compiler to see that the value converted is never negative. But in this patch __bswap_constant_16 is changed to use signed 0xff so that no such implicit conversion occurs at all, and a test with -Werror -Wsign-conversion is added. Bug 17082 objects to the use of ({}) statement expressions in these macros preventing use at file scope (in C, that's in sizeof etc.; in C++, more generally in static initializers). The particular case of these interfaces is fixed by this patch as it changes them to inline functions, eliminating all uses of ({}) in bits/byteswap.h, and a corresponding testcase is added. The bug tries to raise a more general policy question about use of ({}) in macros in installed headers, referring to "many other libc functions" (unspecified which functions are being considered). Since such policy questions belong on libc-alpha, and since there *are* macros in installed headers which can't really avoid using ({}) (where they are type-generic, so can't use an inline function, but need a temporary variable, and a few where the interface involves returning memory from alloca so can't use an inline function either), I propose to consider that bug fixed with this change. That is without prejudice to any other new bugs anyone wishes to file *for precisely defined sets of macros* requesting moving away from ({}) *where it is clearly possible for those interfaces*. Where ({}) can be avoided, typically by use of an inline function, I think that's a good idea - that inline functions are typically to be preferred to ({}) for header interfaces where such optimizations are useful but the interface is suited to being defined using an inline function. Bug 20530 requests use of __builtin_bswap16 when available (GCC 4.8 and later), which this patch implements. Tested for x86_64, and with build-many-glibcs.py. Also did an x86_64 test with the __GNUC_PREREQ conditionals changed to "#if 0" to verify the old-GCC/non-GCC case in the headers. (There are already existing tests for correctness of results of these interfaces.) [BZ #14508] [BZ #15512] [BZ #17082] [BZ #20530] * bits/byteswap.h: Update file comment. Do not include <bits/byteswap-16.h>. (__bswap_constant_16): Cast result to __uint16_t. Use signed 0xff constant. (__bswap_16): Define as inline function. (__bswap_constant_32): Reformat definition. (__bswap_32): Always define as inline function, not macro, using __uint32_t. Use __builtin_bswap32 if [__GNUC_PREREQ (4, 3)], otherwise __bswap_constant_32. (__bswap_constant_64): Reformat definition. Do not use __extension__ here. (__bswap_64): Always define as inline function, not macro. Use __extension__ on function definition. Use __builtin_bswap64 if [__GNUC_PREREQ (4, 3)], otherwise __bswap_constant_64. * string/test-endian-file-scope.c: New file. * string/test-endian-sign-conversion.c: Likewise. * string/Makefile (headers): Remove bits/byteswap-16.h. (tests): Add test-endian-file-scope and test-endian-sign-conversion. (CFLAGS-test-endian-sign-conversion.c): New variable. * bits/byteswap-16.h: Remove file. * sysdeps/ia64/bits/byteswap-16.h: Likewise. * sysdeps/ia64/bits/byteswap.h: Likewise. * sysdeps/m68k/bits/byteswap.h: Likewise. * sysdeps/s390/bits/byteswap-16.h: Likewise. * sysdeps/s390/bits/byteswap.h: Likewise. * sysdeps/tile/bits/byteswap.h: Likewise. * sysdeps/x86/bits/byteswap-16.h: Likewise. * sysdeps/x86/bits/byteswap.h: Likewise.	2018-02-06 21:55:08 +00:00