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124 lines
3.6 KiB
Plaintext
124 lines
3.6 KiB
Plaintext
# Macros to detect C compiler features
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# $Header: /cvsroot/pgsql/config/c-compiler.m4,v 1.5.2.1 2004/02/02 04:08:02 tgl Exp $
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# PGAC_C_SIGNED
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# -------------
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# Check if the C compiler understands signed types.
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AC_DEFUN([PGAC_C_SIGNED],
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[AC_CACHE_CHECK(for signed types, pgac_cv_c_signed,
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[AC_TRY_COMPILE([],
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[signed char c; signed short s; signed int i;],
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[pgac_cv_c_signed=yes],
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[pgac_cv_c_signed=no])])
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if test x"$pgac_cv_c_signed" = xno ; then
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AC_DEFINE(signed,, [Define empty if the C compiler does not understand signed types])
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fi])# PGAC_C_SIGNED
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# PGAC_TYPE_64BIT_INT(TYPE)
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# -------------------------
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# Check if TYPE is a working 64 bit integer type. Set HAVE_TYPE_64 to
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# yes or no respectively, and define HAVE_TYPE_64 if yes.
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AC_DEFUN([PGAC_TYPE_64BIT_INT],
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[define([Ac_define], [translit([have_$1_64], [a-z *], [A-Z_P])])dnl
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define([Ac_cachevar], [translit([pgac_cv_type_$1_64], [ *], [_p])])dnl
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AC_CACHE_CHECK([whether $1 is 64 bits], [Ac_cachevar],
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[AC_TRY_RUN(
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[typedef $1 int64;
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/*
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* These are globals to discourage the compiler from folding all the
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* arithmetic tests down to compile-time constants.
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*/
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int64 a = 20000001;
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int64 b = 40000005;
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int does_int64_work()
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{
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int64 c,d;
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if (sizeof(int64) != 8)
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return 0; /* definitely not the right size */
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/* Do perfunctory checks to see if 64-bit arithmetic seems to work */
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c = a * b;
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d = (c + b) / b;
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if (d != a+1)
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return 0;
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return 1;
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}
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main() {
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exit(! does_int64_work());
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}],
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[Ac_cachevar=yes],
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[Ac_cachevar=no],
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[Ac_cachevar=no
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dnl We will do better here with Autoconf 2.50
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AC_MSG_WARN([64 bit arithmetic disabled when cross-compiling])])])
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Ac_define=$Ac_cachevar
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if test x"$Ac_cachevar" = xyes ; then
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AC_DEFINE(Ac_define,, [Set to 1 if `]$1[' is 64 bits])
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fi
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undefine([Ac_define])dnl
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undefine([Ac_cachevar])dnl
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])# PGAC_TYPE_64BIT_INT
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# PGAC_CHECK_ALIGNOF(TYPE, [INCLUDES = DEFAULT-INCLUDES])
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# -----------------------------------------------------
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# Find the alignment requirement of the given type. Define the result
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# as ALIGNOF_TYPE. This macro works even when cross compiling.
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# (Modelled after AC_CHECK_SIZEOF.)
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AC_DEFUN([PGAC_CHECK_ALIGNOF],
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[AS_LITERAL_IF([$1], [],
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[AC_FATAL([$0: requires literal arguments])])dnl
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AC_CHECK_TYPE([$1], [], [], [$2])
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AC_CACHE_CHECK([alignment of $1], [AS_TR_SH([pgac_cv_alignof_$1])],
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[if test "$AS_TR_SH([ac_cv_type_$1])" = yes; then
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_AC_COMPUTE_INT([((char*) & pgac_struct.field) - ((char*) & pgac_struct)],
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[AS_TR_SH([pgac_cv_alignof_$1])],
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[AC_INCLUDES_DEFAULT([$2])
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struct { char filler; $1 field; } pgac_struct;],
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[AC_MSG_ERROR([cannot compute alignment of $1, 77])])
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else
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AS_TR_SH([pgac_cv_alignof_$1])=0
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fi])dnl
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AC_DEFINE_UNQUOTED(AS_TR_CPP(alignof_$1),
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[$AS_TR_SH([pgac_cv_alignof_$1])],
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[The alignment requirement of a `$1'])
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])# PGAC_CHECK_ALIGNOF
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# PGAC_PROG_CC_NO_STRICT_ALIASING
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# -------------------------------
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# Find out how to turn off strict aliasing in the C compiler.
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AC_DEFUN([PGAC_PROG_CC_NO_STRICT_ALIASING],
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[AC_CACHE_CHECK([how to turn off strict aliasing in $CC],
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pgac_cv_prog_cc_no_strict_aliasing,
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[pgac_save_CFLAGS=$CFLAGS
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if test "$GCC" = yes; then
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pgac_try="-fno-strict-aliasing"
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else
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# Maybe fill in later...
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pgac_try=
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fi
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for pgac_flag in $pgac_try; do
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CFLAGS="$pgac_save_CFLAGS $pgac_flag"
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_AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
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[pgac_cv_prog_cc_no_strict_aliasing=$pgac_try
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break])
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done
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CFLAGS=$pgac_save_CFLAGS
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])
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if test x"$pgac_cv_prog_cc_no_strict_aliasing" != x""; then
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CFLAGS="$CFLAGS $pgac_cv_prog_cc_no_strict_aliasing"
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fi])# PGAC_PROG_CC_NO_STRICT_ALIASING
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