gcc/libstdc++-v3/crossconfig.m4
Jonathan Wakely 932fbc868a libstdc++: Add std::from_chars for floating-point types
This adds the missing std::from_chars overloads for floating-point
types, as required for C++17 conformance.

The implementation is a hack and not intended to be used in the long
term. Rather than parsing the string directly, this determines the
initial portion of the string that matches the pattern determined by the
chars_format parameter, then creates a NTBS to be parsed by strtod (or
strtold or strtof).

Because creating a NTBS requires allocating memory, but std::from_chars
is noexcept, we need to be careful to minimise allocation. Even after
being careful, allocation failure is still possible, and so a
non-conforming std::no_more_memory error code might be returned.

Because strtod et al depend on the current locale, but std::from_chars
does not, we change the current thread's locale to "C" using newlocale
and uselocale before calling strtod, and restore it afterwards.

Because strtod doesn't have the equivalent of a std::chars_format
parameter, it has to examine the input to determine the format in use,
even though the std::from_chars code has already parsed it once (or
twice for large input strings!)

By replacing the use of strtod we could avoid allocation, avoid changing
locale, and use optimised code paths specific to each std::chars_format
case. We would also get more portable behaviour, rather than depending
on the presence of uselocale, and on any bugs or quirks of the target
libc's strtod. Replacing strtod is a project for a later date.

libstdc++-v3/ChangeLog:

	* acinclude.m4 (libtool_VERSION): Bump version.
	* config.h.in: Regenerate.
	* config/abi/pre/gnu.ver: Add GLIBCXX_3.4.29 version and new
	exports.
	* config/os/gnu-linux/ldbl-extra.ver: Add _GLIBCXX_LDBL_3.4.29
	version and new export.
	* configure: Regenerate.
	* configure.ac: Check for <xlocale.h> and uselocale.
	* crossconfig.m4: Add macro or checks for uselocale.
	* include/std/charconv (from_chars): Declare overloads for
	float, double, and long double.
	* src/c++17/Makefile.am: Add new file.
	* src/c++17/Makefile.in: Regenerate.
	* src/c++17/floating_from_chars.cc: New file.
	(from_chars): Define for float, double, and long double.
	* testsuite/20_util/from_chars/1_c++20_neg.cc: Prune extra
	diagnostics caused by new overloads.
	* testsuite/20_util/from_chars/1_neg.cc: Likewise.
	* testsuite/20_util/from_chars/2.cc: Check leading '+'.
	* testsuite/20_util/from_chars/4.cc: New test.
	* testsuite/20_util/from_chars/5.cc: New test.
	* testsuite/util/testsuite_abi.cc: Add new symbol versions.
2020-07-20 23:49:27 +01:00

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dnl
dnl This file contains details for non-native builds.
dnl
AC_DEFUN([GLIBCXX_CROSSCONFIG],[
# Base decisions on target environment.
case "${host}" in
arm*-*-symbianelf*)
# This is a freestanding configuration; there is nothing to do here.
;;
avr*-*-*)
AC_DEFINE(HAVE_ACOSF)
AC_DEFINE(HAVE_ASINF)
AC_DEFINE(HAVE_ATAN2F)
AC_DEFINE(HAVE_ATANF)
AC_DEFINE(HAVE_CEILF)
AC_DEFINE(HAVE_COSF)
AC_DEFINE(HAVE_COSHF)
AC_DEFINE(HAVE_EXPF)
AC_DEFINE(HAVE_FABSF)
AC_DEFINE(HAVE_FLOORF)
AC_DEFINE(HAVE_FMODF)
AC_DEFINE(HAVE_FREXPF)
AC_DEFINE(HAVE_SQRTF)
AC_DEFINE(HAVE_HYPOTF)
AC_DEFINE(HAVE_LDEXPF)
AC_DEFINE(HAVE_LOG10F)
AC_DEFINE(HAVE_LOGF)
AC_DEFINE(HAVE_MODFF)
AC_DEFINE(HAVE_POWF)
AC_DEFINE(HAVE_SINF)
AC_DEFINE(HAVE_SINHF)
AC_DEFINE(HAVE_TANF)
AC_DEFINE(HAVE_TANHF)
;;
mips*-sde-elf*)
# These definitions are for the SDE C library rather than newlib.
SECTION_FLAGS='-ffunction-sections -fdata-sections'
AC_SUBST(SECTION_FLAGS)
GLIBCXX_CHECK_COMPILER_FEATURES
GLIBCXX_CHECK_LINKER_FEATURES
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
AC_DEFINE(HAVE_FINITE)
AC_DEFINE(HAVE_HYPOT)
AC_DEFINE(HAVE_ISNAN)
AC_DEFINE(HAVE_ISINF)
AC_DEFINE(HAVE_LDEXPF)
AC_DEFINE(HAVE_MODF)
AC_DEFINE(HAVE_SQRTF)
;;
*-aix*)
GLIBCXX_CHECK_LINKER_FEATURES
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
AC_DEFINE(_GLIBCXX_USE_DEV_RANDOM)
AC_DEFINE(_GLIBCXX_USE_RANDOM_TR1)
# We don't yet support AIX's TLS ABI.
#GCC_CHECK_TLS
AM_ICONV
AC_DEFINE(HAVE_USELOCALE)
;;
*-darwin*)
# Darwin versions vary, but the linker should work in a cross environment,
# so we just check for all the features here.
# Check for available headers.
# Don't call GLIBCXX_CHECK_LINKER_FEATURES, Darwin doesn't have a GNU ld
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
AC_CHECK_FUNCS(uselocale)
;;
*djgpp)
# GLIBCXX_CHECK_MATH_SUPPORT
AC_DEFINE(HAVE_ISINF)
AC_DEFINE(HAVE_ISNAN)
AC_DEFINE(HAVE_FINITE)
AC_DEFINE(HAVE_SINCOS)
AC_DEFINE(HAVE_HYPOT)
;;
*-freebsd*)
SECTION_FLAGS='-ffunction-sections -fdata-sections'
AC_SUBST(SECTION_FLAGS)
GLIBCXX_CHECK_LINKER_FEATURES
AC_DEFINE(HAVE_SETENV)
AC_DEFINE(HAVE_FINITEF)
AC_DEFINE(HAVE_FINITE)
AC_DEFINE(HAVE_FREXPF)
AC_DEFINE(HAVE_HYPOT)
AC_DEFINE(HAVE_HYPOTF)
AC_DEFINE(HAVE_ISINF)
AC_DEFINE(HAVE_ISNAN)
AC_DEFINE(HAVE_ISNANF)
AC_DEFINE(HAVE_ACOSF)
AC_DEFINE(HAVE_ASINF)
AC_DEFINE(HAVE_ATAN2F)
AC_DEFINE(HAVE_ATANF)
AC_DEFINE(HAVE_CEILF)
AC_DEFINE(HAVE_COSF)
AC_DEFINE(HAVE_COSHF)
AC_DEFINE(HAVE_EXPF)
AC_DEFINE(HAVE_FABSF)
AC_DEFINE(HAVE_FLOORF)
AC_DEFINE(HAVE_FMODF)
AC_DEFINE(HAVE_FREXPF)
AC_DEFINE(HAVE_LDEXPF)
AC_DEFINE(HAVE_LOG10F)
AC_DEFINE(HAVE_LOGF)
AC_DEFINE(HAVE_MODFF)
AC_DEFINE(HAVE_POWF)
AC_DEFINE(HAVE_SINF)
AC_DEFINE(HAVE_SINHF)
AC_DEFINE(HAVE_SQRTF)
AC_DEFINE(HAVE_TANF)
AC_DEFINE(HAVE_TANHF)
if test x"long_double_math_on_this_cpu" = x"yes"; then
AC_DEFINE(HAVE_FINITEL)
AC_DEFINE(HAVE_ISINFL)
AC_DEFINE(HAVE_ISNANL)
fi
AC_CHECK_FUNCS(__cxa_thread_atexit)
AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
AC_CHECK_FUNCS(timespec_get)
AC_CHECK_FUNCS(sockatmark)
AC_CHECK_FUNCS(uselocale)
;;
*-fuchsia*)
SECTION_FLAGS='-ffunction-sections -fdata-sections'
AC_SUBST(SECTION_FLAGS)
;;
*-hpux*)
SECTION_FLAGS='-ffunction-sections -fdata-sections'
AC_SUBST(SECTION_FLAGS)
GLIBCXX_CHECK_LINKER_FEATURES
# GLIBCXX_CHECK_MATH_SUPPORT
AC_DEFINE(HAVE_ISNAN)
AC_DEFINE(HAVE_HYPOT)
AC_DEFINE(HAVE_ACOSF)
AC_DEFINE(HAVE_ASINF)
AC_DEFINE(HAVE_ATANF)
AC_DEFINE(HAVE_COSF)
AC_DEFINE(HAVE_COSHF)
AC_DEFINE(HAVE_SINF)
AC_DEFINE(HAVE_SINHF)
AC_DEFINE(HAVE_TANF)
AC_DEFINE(HAVE_TANHF)
AC_DEFINE(HAVE_EXPF)
AC_DEFINE(HAVE_ATAN2F)
AC_DEFINE(HAVE_FABSF)
AC_DEFINE(HAVE_FMODF)
AC_DEFINE(HAVE_FREXPF)
AC_DEFINE(HAVE_LOGF)
AC_DEFINE(HAVE_LOG10F)
AC_DEFINE(HAVE_MODF)
AC_DEFINE(HAVE_POWF)
AC_DEFINE(HAVE_SQRTF)
# GLIBCXX_CHECK_STDLIB_SUPPORT
AC_DEFINE(HAVE_STRTOLD)
GCC_CHECK_TLS
case "$target" in
*-hpux10*)
AC_DEFINE(HAVE_ISINF)
AC_DEFINE(HAVE_ISINFF)
AC_DEFINE(HAVE_ISNANF)
AC_DEFINE(HAVE_FINITE)
AC_DEFINE(HAVE_FINITEF)
;;
esac
;;
*-linux* | *-uclinux* | *-gnu* | *-kfreebsd*-gnu | *-cygwin* | *-solaris*)
GLIBCXX_CHECK_COMPILER_FEATURES
GLIBCXX_CHECK_LINKER_FEATURES
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
AC_DEFINE(_GLIBCXX_USE_DEV_RANDOM)
AC_DEFINE(_GLIBCXX_USE_RANDOM_TR1)
GCC_CHECK_TLS
AC_CHECK_FUNCS(__cxa_thread_atexit_impl)
AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
AC_CHECK_FUNCS(timespec_get)
AC_CHECK_FUNCS(sockatmark)
AC_CHECK_FUNCS(uselocale)
AM_ICONV
;;
*-mingw32*)
GLIBCXX_CHECK_LINKER_FEATURES
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
AC_CHECK_FUNCS(_wfopen)
;;
*-netbsd* | *-openbsd*)
SECTION_FLAGS='-ffunction-sections -fdata-sections'
AC_SUBST(SECTION_FLAGS)
GLIBCXX_CHECK_LINKER_FEATURES
AC_DEFINE(HAVE_FINITEF)
AC_DEFINE(HAVE_FINITE)
AC_DEFINE(HAVE_FREXPF)
AC_DEFINE(HAVE_HYPOTF)
AC_DEFINE(HAVE_ISINF)
AC_DEFINE(HAVE_ISINFF)
AC_DEFINE(HAVE_ISNAN)
AC_DEFINE(HAVE_ISNANF)
if test x"long_double_math_on_this_cpu" = x"yes"; then
AC_DEFINE(HAVE_FINITEL)
AC_DEFINE(HAVE_ISINFL)
AC_DEFINE(HAVE_ISNANL)
fi
AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
AC_CHECK_FUNCS(timespec_get)
AC_CHECK_FUNCS(sockatmark)
;;
*-qnx6.1* | *-qnx6.2*)
SECTION_FLAGS='-ffunction-sections -fdata-sections'
AC_SUBST(SECTION_FLAGS)
GLIBCXX_CHECK_LINKER_FEATURES
AC_DEFINE(HAVE_COSF)
AC_DEFINE(HAVE_COSL)
AC_DEFINE(HAVE_COSHF)
AC_DEFINE(HAVE_COSHL)
AC_DEFINE(HAVE_LOGF)
AC_DEFINE(HAVE_LOGL)
AC_DEFINE(HAVE_LOG10F)
AC_DEFINE(HAVE_LOG10L)
AC_DEFINE(HAVE_SINF)
AC_DEFINE(HAVE_SINL)
AC_DEFINE(HAVE_SINHF)
AC_DEFINE(HAVE_SINHL)
;;
*-rtems*)
GLIBCXX_CHECK_COMPILER_FEATURES
GLIBCXX_CHECK_LINKER_FEATURES
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
;;
*-tpf)
SECTION_FLAGS='-ffunction-sections -fdata-sections'
SECTION_LDFLAGS='-Wl,--gc-sections $SECTION_LDFLAGS'
AC_SUBST(SECTION_FLAGS)
AC_DEFINE(HAVE_FINITE)
AC_DEFINE(HAVE_FINITEF)
AC_DEFINE(HAVE_FREXPF)
AC_DEFINE(HAVE_HYPOTF)
AC_DEFINE(HAVE_ISINF)
AC_DEFINE(HAVE_ISINFF)
AC_DEFINE(HAVE_ISNAN)
AC_DEFINE(HAVE_ISNANF)
AC_DEFINE(HAVE_SINCOS)
AC_DEFINE(HAVE_SINCOSF)
if test x"long_double_math_on_this_cpu" = x"yes"; then
AC_DEFINE(HAVE_FINITEL)
AC_DEFINE(HAVE_HYPOTL)
AC_DEFINE(HAVE_ISINFL)
AC_DEFINE(HAVE_ISNANL)
fi
;;
*-*vms*)
# Check for available headers.
# Don't call GLIBCXX_CHECK_LINKER_FEATURES, VMS doesn't have a GNU ld
GLIBCXX_CHECK_MATH_SUPPORT
GLIBCXX_CHECK_STDLIB_SUPPORT
;;
*-vxworks)
AC_DEFINE(HAVE_ACOSF)
AC_DEFINE(HAVE_ASINF)
AC_DEFINE(HAVE_ATAN2F)
AC_DEFINE(HAVE_ATANF)
AC_DEFINE(HAVE_CEILF)
AC_DEFINE(HAVE_COSF)
AC_DEFINE(HAVE_COSHF)
AC_DEFINE(HAVE_EXPF)
AC_DEFINE(HAVE_FABSF)
AC_DEFINE(HAVE_FLOORF)
AC_DEFINE(HAVE_FMODF)
AC_DEFINE(HAVE_HYPOT)
AC_DEFINE(HAVE_LOG10F)
AC_DEFINE(HAVE_LOGF)
AC_DEFINE(HAVE_POWF)
AC_DEFINE(HAVE_SINF)
AC_DEFINE(HAVE_SINHF)
AC_DEFINE(HAVE_SQRTF)
AC_DEFINE(HAVE_TANF)
AC_DEFINE(HAVE_TANHF)
dnl # Different versions and execution modes implement different
dnl # subsets of these functions. Instead of hard-coding, test for C
dnl # declarations in headers. The C primitives could be defined as
dnl # macros, in which case the tests might fail, and we might have to
dnl # switch to more elaborate tests.
GLIBCXX_CHECK_MATH_DECLS([
acosl asinl atan2l atanl ceill cosl coshl expl fabsl floorl fmodl
frexpl ldexpl log10l logl modfl powl sinl sinhl sqrtl tanl tanhl hypotl
ldexpf modff hypotf frexpf])
dnl # sincosl is the only one missing here, compared with the *l
dnl # functions in the list guarded by
dnl # long_double_math_on_this_cpu in configure.ac, right after
dnl # the expansion of the present macro.
;;
*)
AC_MSG_ERROR([No support for this host/target combination.])
;;
esac
])
dnl
dnl Check to see if the (math function) argument passed is
dnl declared when using the c compiler
dnl
dnl Define HAVE_CARGF etc if "cargf" is declared
dnl
dnl argument 1 is name of function to check
dnl
dnl ASSUMES argument is a math function
dnl
dnl GLIBCXX_CHECK_MATH_DECL
AC_DEFUN([GLIBCXX_CHECK_MATH_DECL], [
AC_CACHE_CHECK([for $1 declaration],
[glibcxx_cv_func_$1_use], [
AC_LANG_SAVE
AC_LANG_C
AC_TRY_COMPILE([
#include <math.h>
#ifdef HAVE_IEEEFP_H
# include <ieeefp.h>
#endif
#undef $1
], [
void (*f)(void) = (void (*)(void))$1;
], [glibcxx_cv_func_$1_use=yes
], [glibcxx_cv_func_$1_use=no])])
if test "x$glibcxx_cv_func_$1_use" = xyes; then
AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1]))
fi
])
dnl
dnl Check to see whether multiple math functions are
dnl declared when using the c compiler
dnl
dnl Define HAVE_CARGF HAVE_POWL etc if "cargf" and "powl"
dnl are declared
dnl
dnl argument 1 is a word list naming function to check
dnl
dnl ASSUMES arguments are math functions
dnl
dnl GLIBCXX_CHECK_MATH_DECLS
AC_DEFUN([GLIBCXX_CHECK_MATH_DECLS], [
m4_foreach_w([glibcxx_func], [$1], [
GLIBCXX_CHECK_MATH_DECL(glibcxx_func)
])
])