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Always use our own versions of *printf().

Browse Source 
We've spent an awful lot of effort over the years in coping with
platform-specific vagaries of the *printf family of functions.  Let's just
forget all that mess and standardize on always using src/port/snprintf.c.
This gets rid of a lot of configure logic, and it will allow a saner
approach to dealing with %m (though actually changing that is left for
a follow-on patch).

Preliminary performance testing suggests that as it stands, snprintf.c is
faster than the native printf functions for some tasks on some platforms,
and slower for other cases.  A pending patch will improve that, though
cases with floating-point conversions will doubtless remain slower unless
we want to put a *lot* of effort into that.  Still, we've not observed
that *printf is really a performance bottleneck for most workloads, so
I doubt this matters much.

Patch by me, reviewed by Michael Paquier

Discussion: https://postgr.es/m/2975.1526862605@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2018-09-26 13:13:57 -04:00
parent 758ce9b779
commit 96bf88d527
16 changed files with 19 additions and 509 deletions
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254
configure vendored
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@ -15367,97 +15367,6 @@ $as_echo "#define HAVE_PS_STRINGS 1" >>confdefs.h
fi
# We use our snprintf.c emulation if either snprintf() or vsnprintf()
# is missing. Yes, there are machines that have only one. We may
# also decide to use snprintf.c if snprintf() is present but does not
# have all the features we need --- see below.
if test "$PORTNAME" = "win32"; then
# Win32 gets snprintf.c built unconditionally.
#
# To properly translate all NLS languages strings, we must support the
# *printf() %$ format, which allows *printf() arguments to be selected
# by position in the translated string.
#
# libintl versions < 0.13 use the native *printf() functions, and Win32
# *printf() doesn't understand %$, so we must use our /port versions,
# which do understand %$. libintl versions >= 0.13 include their own
# *printf versions on Win32. The libintl 0.13 release note text is:
#
# C format strings with positions, as they arise when a translator
# needs to reorder a sentence, are now supported on all platforms.
# On those few platforms (NetBSD and Woe32) for which the native
# printf()/fprintf()/... functions don't support such format
# strings, replacements are provided through <libintl.h>.
#
# We could use libintl >= 0.13's *printf() if we were sure that we had
# a libintl >= 0.13 at runtime, but seeing that there is no clean way
# to guarantee that, it is best to just use our own, so we are sure to
# get %$ support. In include/port.h we disable the *printf() macros
# that might have been defined by libintl.
#
# We do this unconditionally whether NLS is used or not so we are sure
# that all Win32 libraries and binaries behave the same.
pgac_need_repl_snprintf=yes
else
pgac_need_repl_snprintf=no
for ac_func in snprintf
do :
ac_fn_c_check_func "$LINENO" "snprintf" "ac_cv_func_snprintf"
if test "x$ac_cv_func_snprintf" = xyes; then :
cat >>confdefs.h <<_ACEOF
#define HAVE_SNPRINTF 1
_ACEOF
else
pgac_need_repl_snprintf=yes
fi
done
for ac_func in vsnprintf
do :
ac_fn_c_check_func "$LINENO" "vsnprintf" "ac_cv_func_vsnprintf"
if test "x$ac_cv_func_vsnprintf" = xyes; then :
cat >>confdefs.h <<_ACEOF
#define HAVE_VSNPRINTF 1
_ACEOF
else
pgac_need_repl_snprintf=yes
fi
done
fi
# Check whether <stdio.h> declares snprintf() and vsnprintf(); if not,
# include/c.h will provide declarations. Note this is a separate test
# from whether the functions exist in the C library --- there are
# systems that have the functions but don't bother to declare them :-(
ac_fn_c_check_decl "$LINENO" "snprintf" "ac_cv_have_decl_snprintf" "$ac_includes_default"
if test "x$ac_cv_have_decl_snprintf" = xyes; then :
ac_have_decl=1
else
ac_have_decl=0
fi
cat >>confdefs.h <<_ACEOF
#define HAVE_DECL_SNPRINTF $ac_have_decl
_ACEOF
ac_fn_c_check_decl "$LINENO" "vsnprintf" "ac_cv_have_decl_vsnprintf" "$ac_includes_default"
if test "x$ac_cv_have_decl_vsnprintf" = xyes; then :
ac_have_decl=1
else
ac_have_decl=0
fi
cat >>confdefs.h <<_ACEOF
#define HAVE_DECL_VSNPRINTF $ac_have_decl
_ACEOF
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for isinf" >&5
$as_echo_n "checking for isinf... " >&6; }
if ${ac_cv_func_isinf+:} false; then :
@ -16175,53 +16084,6 @@ fi
# Run tests below here
# --------------------
# For NLS, force use of our snprintf if system's doesn't do arg control.
# See comment above at snprintf test for details.
if test "$enable_nls" = yes -a "$pgac_need_repl_snprintf" = no; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether snprintf supports argument control" >&5
$as_echo_n "checking whether snprintf supports argument control... " >&6; }
if ${pgac_cv_snprintf_arg_control+:} false; then :
$as_echo_n "(cached) " >&6
else
if test "$cross_compiling" = yes; then :
pgac_cv_snprintf_arg_control=cross
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
#include <stdio.h>
#include <string.h>
int main()
{
char buf[100];
/* can it swap arguments? */
snprintf(buf, 100, "%2\$d %1\$d", 3, 4);
if (strcmp(buf, "4 3") != 0)
return 1;
return 0;
}
_ACEOF
if ac_fn_c_try_run "$LINENO"; then :
pgac_cv_snprintf_arg_control=yes
else
pgac_cv_snprintf_arg_control=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
conftest.$ac_objext conftest.beam conftest.$ac_ext
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_snprintf_arg_control" >&5
$as_echo "$pgac_cv_snprintf_arg_control" >&6; }
if test $pgac_cv_snprintf_arg_control != yes ; then
pgac_need_repl_snprintf=yes
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether long int is 64 bits" >&5
$as_echo_n "checking whether long int is 64 bits... " >&6; }
@ -16401,8 +16263,6 @@ _ACEOF
# Select the printf length modifier that goes with that, too.
# (This used to be bound up with replacement-snprintf selection, but now
# we assume that the native *printf functions use standard length modifiers.)
if test x"$pg_int64_type" = x"long long int" ; then
INT64_MODIFIER='"ll"'
else
@ -16415,120 +16275,6 @@ cat >>confdefs.h <<_ACEOF
_ACEOF
# Force use of our snprintf if the system's doesn't support the %z flag.
# (Note this test uses PG_INT64_TYPE and INT64_MODIFIER.)
if test "$pgac_need_repl_snprintf" = no; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether snprintf supports the %z modifier" >&5
$as_echo_n "checking whether snprintf supports the %z modifier... " >&6; }
if ${pgac_cv_snprintf_size_t_support+:} false; then :
$as_echo_n "(cached) " >&6
else
if test "$cross_compiling" = yes; then :
pgac_cv_snprintf_size_t_support=cross
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
#include <stdio.h>
#include <string.h>
int main()
{
char bufz[100];
char buf64[100];
/*
* Print the largest unsigned number fitting in a size_t using both %zu
* and the previously-determined format for 64-bit integers. Note that
* we don't run this code unless we know snprintf handles 64-bit ints.
*/
bufz[0] = '\0'; /* in case snprintf fails to emit anything */
snprintf(bufz, sizeof(bufz), "%zu", ~((size_t) 0));
snprintf(buf64, sizeof(buf64), "%" INT64_MODIFIER "u",
(unsigned PG_INT64_TYPE) ~((size_t) 0));
if (strcmp(bufz, buf64) != 0)
return 1;
return 0;
}
_ACEOF
if ac_fn_c_try_run "$LINENO"; then :
pgac_cv_snprintf_size_t_support=yes
else
pgac_cv_snprintf_size_t_support=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
conftest.$ac_objext conftest.beam conftest.$ac_ext
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_snprintf_size_t_support" >&5
$as_echo "$pgac_cv_snprintf_size_t_support" >&6; }
if test "$pgac_cv_snprintf_size_t_support" != yes; then
pgac_need_repl_snprintf=yes
fi
fi
# Force use of our snprintf if the system's doesn't handle buffer overrun
# as specified by C99.
if test "$pgac_need_repl_snprintf" = no; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether snprintf handles buffer overrun per C99" >&5
$as_echo_n "checking whether snprintf handles buffer overrun per C99... " >&6; }
if ${pgac_cv_snprintf_c99_result+:} false; then :
$as_echo_n "(cached) " >&6
else
if test "$cross_compiling" = yes; then :
pgac_cv_snprintf_c99_result=cross
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
#include <stdio.h>
#include <string.h>
int main()
{
char buf[10];
strcpy(buf, "abcdefghi");
if (snprintf(buf, 4, "%d", 123456) != 6)
return 1;
if (strcmp(buf, "123") != 0 || buf[4] != 'e')
return 1;
return 0;
}
_ACEOF
if ac_fn_c_try_run "$LINENO"; then :
pgac_cv_snprintf_c99_result=yes
else
pgac_cv_snprintf_c99_result=no
fi
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
conftest.$ac_objext conftest.beam conftest.$ac_ext
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_snprintf_c99_result" >&5
$as_echo "$pgac_cv_snprintf_c99_result" >&6; }
if test "$pgac_cv_snprintf_c99_result" != yes; then
pgac_need_repl_snprintf=yes
fi
fi
# Now we have checked all the reasons to replace snprintf
if test $pgac_need_repl_snprintf = yes; then
$as_echo "#define USE_REPL_SNPRINTF 1" >>confdefs.h
case " $LIBOBJS " in
*" snprintf.$ac_objext "* ) ;;
*) LIBOBJS="$LIBOBJS snprintf.$ac_objext"
;;
esac
fi
# has to be down here, rather than with the other builtins, because
# the test uses PG_INT64_TYPE.
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __builtin_mul_overflow" >&5