glibc/scripts/check-installed-headers.sh
Zack Weinberg 711a322a23
Use a proper C tokenizer to implement the obsolete typedefs test.
The test for obsolete typedefs in installed headers was implemented
using grep, and could therefore get false positives on e.g. “ulong”
in a comment.  It was also scanning all of the headers included by
our headers, and therefore testing headers we don’t control, e.g.
Linux kernel headers.

This patch splits the obsolete-typedef test from
scripts/check-installed-headers.sh to a separate program,
scripts/check-obsolete-constructs.py.  Being implemented in Python,
it is feasible to make it tokenize C accurately enough to avoid false
positives on the contents of comments and strings.  It also only
examines $(headers) in each subdirectory--all the headers we install,
but not any external dependencies of those headers.  Headers whose
installed name starts with finclude/ are ignored, on the assumption
that they contain Fortran.

It is also feasible to make the new test understand the difference
between _defining_ the obsolete typedefs and _using_ the obsolete
typedefs, which means posix/{bits,sys}/types.h no longer need to be
exempted.  This uncovered an actual bug in bits/types.h: __quad_t and
__u_quad_t were being used to define __S64_TYPE, __U64_TYPE,
__SQUAD_TYPE and __UQUAD_TYPE.  These are changed to __int64_t and
__uint64_t respectively.  This is a safe change, despite the comments
in bits/types.h claiming a difference between __quad_t and __int64_t,
because those comments are incorrect.  In all current ABIs, both
__quad_t and __int64_t are ‘long’ when ‘long’ is a 64-bit type, and
‘long long’ when ‘long’ is a 32-bit type, and similarly for __u_quad_t
and __uint64_t.  (Changing the types to be what the comments say they
are would be an ABI break, as it affects C++ name mangling.)  This
patch includes a minimal change to make the comments not completely
wrong.

sys/types.h was defining the legacy BSD u_intN_t typedefs using a
construct that was not necessarily consistent with how the C99 uintN_t
typedefs are defined, and is also too complicated for the new script to
understand (it lexes C relatively accurately, but it does not attempt
to expand preprocessor macros, nor does it do any actual parsing).
This patch cuts all of that out and uses bits/types.h's __uintN_t typedefs
to define u_intN_t instead.  This is verified to not change the ABI on
any supported architecture, via the c++-types test, which means u_intN_t
and uintN_t were, in fact, consistent on all supported architectures.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

	* scripts/check-obsolete-constructs.py: New test script.
	* scripts/check-installed-headers.sh: Remove tests for
	obsolete typedefs, superseded by check-obsolete-constructs.py.
	* Rules: Run scripts/check-obsolete-constructs.py over $(headers)
	as a special test.  Update commentary.
	* posix/bits/types.h (__SQUAD_TYPE, __S64_TYPE): Define as __int64_t.
	(__UQUAD_TYPE, __U64_TYPE): Define as __uint64_t.
	Update commentary.
	* posix/sys/types.h (__u_intN_t): Remove.
	(u_int8_t): Typedef using __uint8_t.
	(u_int16_t): Typedef using __uint16_t.
	(u_int32_t): Typedef using __uint32_t.
	(u_int64_t): Typedef using __uint64_t.
2019-03-13 09:39:43 -04:00

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#! /bin/sh
# Copyright (C) 2016-2019 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/>.
# For each installed header, confirm that it's possible to compile a
# file that includes that header and does nothing else, in several
# different compilation modes.
# These compilation switches assume GCC or compatible, which is probably
# fine since we also assume that when _building_ glibc.
c_modes="-std=c89 -std=gnu89 -std=c11 -std=gnu11"
cxx_modes="-std=c++98 -std=gnu++98 -std=c++11 -std=gnu++11"
# An exhaustive test of feature selection macros would take far too long.
# These are probably the most commonly used three.
lib_modes="-D_DEFAULT_SOURCE=1 -D_GNU_SOURCE=1 -D_XOPEN_SOURCE=700"
if [ $# -lt 3 ]; then
echo "usage: $0 c|c++ \"compile command\" header header header..." >&2
exit 2
fi
case "$1" in
(c)
lang_modes="$c_modes"
cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test_XXXXXX.c)
;;
(c++)
lang_modes="$cxx_modes"
cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test_XXXXXX.cc)
;;
(*)
echo "usage: $0 c|c++ \"compile command\" header header header..." >&2
exit 2;;
esac
shift
cc_cmd="$1"
shift
trap "rm -f '$cih_test_c'" 0
failed=0
is_x86_64=unknown
is_x32=unknown
for header in "$@"; do
# Skip various headers for which this test gets a false failure.
case "$header" in
# bits/* are not meant to be included directly and usually #error
# out if you try it.
# regexp.h is a stub containing only an #error.
# Sun RPC's .x files are traditionally installed in
# $prefix/include/rpcsvc, but they are not C header files.
(bits/* | regexp.h | rpcsvc/*.x)
continue;;
# All extant versions of sys/elf.h contain nothing more than an
# exhortation (either a #warning or an #error) to use sys/procfs.h
# instead, plus an inclusion of that header.
(sys/elf.h)
continue;;
# Skip Fortran headers.
(finclude/*)
continue;;
# sys/sysctl.h is unsupported for x32.
(sys/sysctl.h)
case "$is_x32" in
(yes) continue;;
(no) ;;
(unknown)
cat >"$cih_test_c" <<EOF
#if defined __x86_64__ && defined __ILP32__
# error "is x32"
#endif
EOF
if $cc_cmd -fsyntax-only "$cih_test_c" > /dev/null 2>&1
then
is_x32=no
else
is_x32=yes
continue
fi
;;
esac
;;
# sys/vm86.h is "unsupported on x86-64" and errors out on that target.
(sys/vm86.h)
case "$is_x86_64" in
(yes) continue;;
(no) ;;
(unknown)
cat >"$cih_test_c" <<EOF
#if defined __x86_64__ && __x86_64__
#error "is x86-64"
#endif
EOF
if $cc_cmd -fsyntax-only "$cih_test_c" > /dev/null 2>&1
then
is_x86_64=no
else
is_x86_64=yes
continue
fi
;;
esac
;;
esac
echo :: "$header"
for lang_mode in "" $lang_modes; do
for lib_mode in "" $lib_modes; do
echo :::: $lang_mode $lib_mode
if [ -z "$lib_mode" ]; then
expanded_lib_mode='/* default library mode */'
else
expanded_lib_mode=$(echo : $lib_mode | \
sed 's/^: -D/#define /; s/=/ /')
fi
cat >"$cih_test_c" <<EOF
/* These macros may have been defined on the command line. They are
inappropriate for this test. */
#undef _LIBC
#undef _GNU_SOURCE
/* The library mode is selected here rather than on the command line to
ensure that this selection wins. */
$expanded_lib_mode
#include <$header>
int avoid_empty_translation_unit;
EOF
if $cc_cmd -fsyntax-only $lang_mode "$cih_test_c" 2>&1
then :
else failed=1
fi
done
done
done
exit $failed