From bc5a4dfcf7390145dc3ba3c1c18c5ce561b778cd Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 25 Nov 2024 13:11:28 +1300 Subject: [PATCH] Assume that conforms to the C standard. Previously we checked "for that conforms to C99" using autoconf's AC_HEADER_STDBOOL macro. We've required C99 since PostgreSQL 12, so the test was redundant, and under C23 it was broken: autoconf 2.69's implementation doesn't understand C23's new empty header (the macros it's looking for went away, replaced by language keywords). Later autoconf versions fixed that, but let's just remove the anachronistic test. HAVE_STDBOOL_H and HAVE__BOOL will no longer be defined, but they weren't directly tested in core or likely extensions (except in 11, see below). PG_USE_STDBOOL (or USE_STDBOOL in 11 and 12) is still defined when sizeof(bool) is 1, which should be true on all modern systems. Otherwise we define our own bool type and values of size 1, which would fail to compile under C23 as revealed by the broken test. (We'll probably clean that dead code up in master, but here we want a minimal back-patchable change.) This came to our attention when GCC 15 recently started using using C23 by default and failed to compile the replacement code, as reported by Sam James and build farm animal alligator. Back-patch to all supported releases, and then two older versions that also know about , per the recently-out-of-support policy[1]. 12 requires C99 so it's much like the supported releases, but 11 only assumes C89 so it now uses AC_CHECK_HEADERS instead of the overly picky AC_HEADER_STDBOOL. (I could find no discussion of which historical systems had but failed the conformance test; if they ever existed, they surely aren't relevant to that policy's goals.) [1] https://wiki.postgresql.org/wiki/Committing_checklist#Policies Reported-by: Sam James Reviewed-by: Peter Eisentraut (master version) Reviewed-by: Tom Lane (approach) Discussion: https://www.postgresql.org/message-id/flat/87o72eo9iu.fsf%40gentoo.org --- configure | 208 ++++++++++--------------------------- configure.ac | 13 +-- meson.build | 9 +- src/include/c.h | 2 +- src/include/pg_config.h.in | 6 -- 5 files changed, 64 insertions(+), 174 deletions(-) diff --git a/configure b/configure index 28719ed30c6..62bf4c7655b 100755 --- a/configure +++ b/configure @@ -2094,60 +2094,6 @@ $as_echo "$ac_res" >&6; } } # ac_fn_c_check_func -# ac_fn_c_check_type LINENO TYPE VAR INCLUDES -# ------------------------------------------- -# Tests whether TYPE exists after having included INCLUDES, setting cache -# variable VAR accordingly. -ac_fn_c_check_type () -{ - as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack - { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5 -$as_echo_n "checking for $2... " >&6; } -if eval \${$3+:} false; then : - $as_echo_n "(cached) " >&6 -else - eval "$3=no" - cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ -$4 -int -main () -{ -if (sizeof ($2)) - return 0; - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ -$4 -int -main () -{ -if (sizeof (($2))) - return 0; - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - -else - eval "$3=yes" -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext -fi -eval ac_res=\$$3 - { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5 -$as_echo "$ac_res" >&6; } - eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno - -} # ac_fn_c_check_type - # ac_fn_c_check_member LINENO AGGR MEMBER VAR INCLUDES # ---------------------------------------------------- # Tries to find if the field MEMBER exists in type AGGR, after including @@ -2205,6 +2151,60 @@ $as_echo "$ac_res" >&6; } } # ac_fn_c_check_member +# ac_fn_c_check_type LINENO TYPE VAR INCLUDES +# ------------------------------------------- +# Tests whether TYPE exists after having included INCLUDES, setting cache +# variable VAR accordingly. +ac_fn_c_check_type () +{ + as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5 +$as_echo_n "checking for $2... " >&6; } +if eval \${$3+:} false; then : + $as_echo_n "(cached) " >&6 +else + eval "$3=no" + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +$4 +int +main () +{ +if (sizeof ($2)) + return 0; + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +$4 +int +main () +{ +if (sizeof (($2))) + return 0; + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + +else + eval "$3=yes" +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext +fi +eval ac_res=\$$3 + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5 +$as_echo "$ac_res" >&6; } + eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno + +} # ac_fn_c_check_type + # ac_fn_c_compute_int LINENO EXPR VAR INCLUDES # -------------------------------------------- # Tries to find the compile-time value of EXPR in a program that includes @@ -13227,100 +13227,6 @@ fi ## Header files ## -{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for stdbool.h that conforms to C99" >&5 -$as_echo_n "checking for stdbool.h that conforms to C99... " >&6; } -if ${ac_cv_header_stdbool_h+:} false; then : - $as_echo_n "(cached) " >&6 -else - cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ - - #include - #ifndef bool - "error: bool is not defined" - #endif - #ifndef false - "error: false is not defined" - #endif - #if false - "error: false is not 0" - #endif - #ifndef true - "error: true is not defined" - #endif - #if true != 1 - "error: true is not 1" - #endif - #ifndef __bool_true_false_are_defined - "error: __bool_true_false_are_defined is not defined" - #endif - - struct s { _Bool s: 1; _Bool t; } s; - - char a[true == 1 ? 1 : -1]; - char b[false == 0 ? 1 : -1]; - char c[__bool_true_false_are_defined == 1 ? 1 : -1]; - char d[(bool) 0.5 == true ? 1 : -1]; - /* See body of main program for 'e'. */ - char f[(_Bool) 0.0 == false ? 1 : -1]; - char g[true]; - char h[sizeof (_Bool)]; - char i[sizeof s.t]; - enum { j = false, k = true, l = false * true, m = true * 256 }; - /* The following fails for - HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */ - _Bool n[m]; - char o[sizeof n == m * sizeof n[0] ? 1 : -1]; - char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1]; - /* Catch a bug in an HP-UX C compiler. See - http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html - http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html - */ - _Bool q = true; - _Bool *pq = &q; - -int -main () -{ - - bool e = &s; - *pq |= q; - *pq |= ! q; - /* Refer to every declared value, to avoid compiler optimizations. */ - return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l - + !m + !n + !o + !p + !q + !pq); - - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - ac_cv_header_stdbool_h=yes -else - ac_cv_header_stdbool_h=no -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext -fi -{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_header_stdbool_h" >&5 -$as_echo "$ac_cv_header_stdbool_h" >&6; } - ac_fn_c_check_type "$LINENO" "_Bool" "ac_cv_type__Bool" "$ac_includes_default" -if test "x$ac_cv_type__Bool" = xyes; then : - -cat >>confdefs.h <<_ACEOF -#define HAVE__BOOL 1 -_ACEOF - - -fi - - -if test $ac_cv_header_stdbool_h = yes; then - -$as_echo "#define HAVE_STDBOOL_H 1" >>confdefs.h - -fi - - for ac_header in atomic.h copyfile.h execinfo.h getopt.h ifaddrs.h mbarrier.h sys/epoll.h sys/event.h sys/personality.h sys/prctl.h sys/procctl.h sys/signalfd.h sys/ucred.h termios.h ucred.h xlocale.h do : as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh` @@ -15061,9 +14967,7 @@ $as_echo_n "checking size of bool... " >&6; } if ${ac_cv_sizeof_bool+:} false; then : $as_echo_n "(cached) " >&6 else - if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (bool))" "ac_cv_sizeof_bool" "#ifdef HAVE_STDBOOL_H -#include -#endif + if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (bool))" "ac_cv_sizeof_bool" "#include "; then : else @@ -15089,7 +14993,7 @@ _ACEOF -if test "$ac_cv_header_stdbool_h" = yes -a "$ac_cv_sizeof_bool" = 1; then +if test "$ac_cv_sizeof_bool" = 1; then $as_echo "#define PG_USE_STDBOOL 1" >>confdefs.h diff --git a/configure.ac b/configure.ac index 533f4ab78a5..c7d01168814 100644 --- a/configure.ac +++ b/configure.ac @@ -1432,8 +1432,6 @@ AC_SUBST(UUID_LIBS) ## Header files ## -AC_HEADER_STDBOOL - AC_CHECK_HEADERS(m4_normalize([ atomic.h copyfile.h @@ -1693,14 +1691,11 @@ if test "$ac_cv_sizeof_off_t" -lt 8; then fi fi -AC_CHECK_SIZEOF([bool], [], -[#ifdef HAVE_STDBOOL_H -#include -#endif]) +AC_CHECK_SIZEOF([bool], [], [#include ]) -dnl We use if we have it and it declares type bool as having -dnl size 1. Otherwise, c.h will fall back to declaring bool as unsigned char. -if test "$ac_cv_header_stdbool_h" = yes -a "$ac_cv_sizeof_bool" = 1; then +dnl We use if bool has size 1 after including it. Otherwise, c.h +dnl will fall back to declaring bool as unsigned char. +if test "$ac_cv_sizeof_bool" = 1; then AC_DEFINE([PG_USE_STDBOOL], 1, [Define to 1 to use to define type bool.]) fi diff --git a/meson.build b/meson.build index b64d253fe41..26b8b47d3ef 100644 --- a/meson.build +++ b/meson.build @@ -1755,12 +1755,9 @@ if cc.compiles(''' endif -# We use if we have it and it declares type bool as having -# size 1. Otherwise, c.h will fall back to declaring bool as unsigned char. -if cc.has_type('_Bool', args: test_c_args) \ - and cc.has_type('bool', prefix: '#include ', args: test_c_args) \ - and cc.sizeof('bool', prefix: '#include ', args: test_c_args) == 1 - cdata.set('HAVE__BOOL', 1) +# We use if bool has size 1 after including it. Otherwise, c.h +# will fall back to declaring bool as unsigned char. +if cc.sizeof('bool', prefix: '#include ', args: test_c_args) == 1 cdata.set('PG_USE_STDBOOL', 1) endif diff --git a/src/include/c.h b/src/include/c.h index 4a6b361231c..fe1ce87882b 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -450,7 +450,7 @@ typedef void (*pg_funcptr_t) (void); * bool * Boolean value, either true or false. * - * We use stdbool.h if available and its bool has size 1. That's useful for + * We use stdbool.h if bool has size 1 after including it. That's useful for * better compiler and debugger output and for compatibility with third-party * libraries. But PostgreSQL currently cannot deal with bool of other sizes; * there are static assertions around the code to prevent that. diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index a903c60a3a0..40e4b2e3816 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -367,9 +367,6 @@ /* Define to 1 if you have the `SSL_CTX_set_num_tickets' function. */ #undef HAVE_SSL_CTX_SET_NUM_TICKETS -/* Define to 1 if stdbool.h conforms to C99. */ -#undef HAVE_STDBOOL_H - /* Define to 1 if you have the header file. */ #undef HAVE_STDINT_H @@ -499,9 +496,6 @@ /* Define to 1 if you have XSAVE intrinsics. */ #undef HAVE_XSAVE_INTRINSICS -/* Define to 1 if the system has the type `_Bool'. */ -#undef HAVE__BOOL - /* Define to 1 if your compiler understands __builtin_bswap16. */ #undef HAVE__BUILTIN_BSWAP16