contrib/ntp/sntp/m4/ntp_compiler.m4

   1 dnl ######################################################################
   2 dnl Common m4sh code for compiler stuff
   3 AC_DEFUN([NTP_COMPILER], [
   4 AC_REQUIRE([AC_PROG_CC_C89])
   5 AC_REQUIRE([AC_PROG_CC_C99])
   6
   7 CFLAGS_NTP=
   8 CPPFLAGS_NTP=
   9 LDADD_NTP=
  10 LDFLAGS_NTP=
  11 AC_SUBST([CFLAGS_NTP])
  12 AC_SUBST([CPPFLAGS_NTP])
  13 AC_SUBST([LDADD_NTP])
  14 AC_SUBST([LDFLAGS_NTP])
  15
  16 case "$ac_cv_prog_cc_c89" in
  17  no)
  18     AC_MSG_WARN([ANSI C89/ISO C90 is the minimum to compile NTP]
  19                 [ version 4.2.5 and higher.])
  20     ;;
  21 esac
  22
  23 AC_CACHE_CHECK(
  24     [if $CC can handle @%:@warning],
  25     [ntp_cv_cpp_warning],
  26     [AC_COMPILE_IFELSE(
  27         [AC_LANG_PROGRAM([[]], [[#warning foo]])],
  28         [ntp_cv_cpp_warning=yes],
  29         [ntp_cv_cpp_warning=no]
  30     )]
  31 )
  32 case "$ntp_cv_cpp_warning" in
  33  no)
  34     AC_DEFINE([NO_OPTION_NAME_WARNINGS], [1],
  35         [Should we avoid @%:@warning on option name collisions?])
  36 esac
  37
  38 AC_CACHE_CHECK(
  39     [if $CC supports __attribute__((...))],
  40     [ntp_cv_cc_attribute],
  41     [AC_COMPILE_IFELSE(
  42         [AC_LANG_PROGRAM(
  43             [[]],
  44             [[void foo(void) __attribute__((__noreturn__));]]
  45             )],
  46         [ntp_cv_cc_attribute=yes],
  47         [ntp_cv_cc_attribute=no]
  48     )]
  49 )
  50 case "$ntp_cv_cc_attribute" in
  51  yes)
  52     AC_DEFINE([HAVE___ATTRIBUTE__], [],
  53         [defined if C compiler supports __attribute__((...))])
  54 esac
  55 AH_VERBATIM(
  56     [HAVE___ATTRIBUTE___VERBATIM],
  57     [
  58         /* define away __attribute__() if unsupported */
  59         #ifndef HAVE___ATTRIBUTE__
  60         # define __attribute__(x) /* empty */
  61         #endif
  62         #define ISC_PLATFORM_NORETURN_PRE
  63         #define ISC_PLATFORM_NORETURN_POST __attribute__((__noreturn__))
  64     ]
  65 )
  66
  67 case "$GCC" in
  68  yes)
  69     SAVED_CFLAGS="$CFLAGS"
  70     CFLAGS="$CFLAGS -Wstrict-overflow"
  71     AC_CACHE_CHECK(
  72         [if $CC can handle -Wstrict-overflow],
  73         [ntp_cv_gcc_Wstrict_overflow],
  74         [AC_COMPILE_IFELSE(
  75             [AC_LANG_PROGRAM([[]], [[]])],
  76             [ntp_cv_gcc_Wstrict_overflow=yes],
  77             [ntp_cv_gcc_Wstrict_overflow=no]
  78         )       ]
  79     )
  80     #
  81     # $ntp_cv_gcc_Wstrict_overflow is tested later to add the
  82     # flag to CFLAGS.
  83     #
  84     CFLAGS="$SAVED_CFLAGS -Winit-self"
  85     AC_CACHE_CHECK(
  86         [if $CC can handle -Winit-self],
  87         [ntp_cv_gcc_Winit_self],
  88         [
  89             AC_COMPILE_IFELSE(
  90                 [AC_LANG_PROGRAM([[]], [[]])],
  91                 [ntp_cv_gcc_Winit_self=yes],
  92                 [ntp_cv_gcc_Winit_self=no]
  93             )
  94         ]
  95     )
  96     CFLAGS="$SAVED_CFLAGS"
  97     AS_UNSET([SAVED_CFLAGS])
  98     #
  99     # $ntp_cv_gcc_Winit_self is tested later to add the
 100     # flag to CFLAGS_NTP.
 101     #
 102     AC_CACHE_CHECK(
 103         [if linker supports omitting unused code and data],
 104         [ntp_cv_gc_sections_runs],
 105         [
 106             dnl  NetBSD will link but likely not run with --gc-sections
 107             dnl  http://bugs.ntp.org/1844
 108             dnl  http://gnats.netbsd.org/40401
 109             dnl  --gc-sections causes attempt to load as linux elf, with
 110             dnl  wrong syscalls in place.  Test a little gauntlet of
 111             dnl  simple stdio read code checking for errors, expecting
 112             dnl  enough syscall differences that the NetBSD code will
 113             dnl  fail even with Linux emulation working as designed.
 114             dnl  A shorter test could be refined by someone with access
 115             dnl  to a NetBSD host with Linux emulation working.
 116             origCFLAGS="$CFLAGS"
 117             CFLAGS="$CFLAGS -Wl,--gc-sections"
 118             AC_LINK_IFELSE(
 119                 [AC_LANG_PROGRAM(
 120                     [[
 121                         #include <stdlib.h>
 122                         #include <stdio.h>
 123                     ]],
 124                     [[
 125                         FILE *  fpC;
 126                         char    buf[32];
 127                         size_t  cch;
 128                         int     read_success_once;
 129
 130                         fpC = fopen("conftest.c", "r");
 131                         if (NULL == fpC)
 132                                 exit(1);
 133                         do {
 134                                 cch = fread(buf, sizeof(buf), 1, fpC);
 135                                 read_success_once |= (0 != cch);
 136                         } while (0 != cch);
 137                         if (!read_success_once)
 138                                 exit(2);
 139                         if (!feof(fpC))
 140                                 exit(3);
 141                         if (0 != fclose(fpC))
 142                                 exit(4);
 143
 144                         exit(EXIT_SUCCESS);
 145                     ]]
 146                 )],
 147                 [
 148                     if test "X$cross_compiling" = "Xyes" || grep gc-sections conftest.err ; then
 149                         ntp_cv_gc_sections_runs=no
 150                     else
 151                         ntp_cv_gc_sections_runs=no
 152                         ./conftest >/dev/null 2>&1 && ntp_cv_gc_sections_runs=yes
 153                     fi
 154                 ],
 155                 [ntp_cv_gc_sections_runs=no]
 156             )
 157             CFLAGS="$origCFLAGS"
 158             AS_UNSET([origCFLAGS])
 159         ]
 160     )
 161     case "$ntp_cv_gc_sections_runs" in
 162      yes)
 163         LDADD_LIBNTP="-Wl,--gc-sections"
 164         CFLAGS_NTP="$CFLAGS_NTP -ffunction-sections -fdata-sections"
 165         ;;
 166      no)
 167         LDADD_LIBNTP=
 168         ;;
 169     esac
 170     CFLAGS_NTP="$CFLAGS_NTP -Wall"
 171     CFLAGS_NTP="$CFLAGS_NTP -Wcast-align"
 172     CFLAGS_NTP="$CFLAGS_NTP -Wcast-qual"
 173     # CFLAGS_NTP="$CFLAGS_NTP -Wconversion"
 174     # CFLAGS_NTP="$CFLAGS_NTP -Werror"
 175     # CFLAGS_NTP="$CFLAGS_NTP -Wextra"
 176     # CFLAGS_NTP="$CFLAGS_NTP -Wfloat-equal"
 177     CFLAGS_NTP="$CFLAGS_NTP -Wmissing-prototypes"
 178     CFLAGS_NTP="$CFLAGS_NTP -Wpointer-arith"
 179     CFLAGS_NTP="$CFLAGS_NTP -Wshadow"
 180     # CFLAGS_NTP="$CFLAGS_NTP -Wtraditional"
 181     # CFLAGS_NTP="$CFLAGS_NTP -Wwrite-strings"
 182     case "$ntp_cv_gcc_Winit_self" in
 183      yes)
 184         CFLAGS_NTP="$CFLAGS_NTP -Winit-self"
 185     esac
 186     case "$ntp_cv_gcc_Wstrict_overflow" in
 187      yes)
 188         CFLAGS_NTP="$CFLAGS_NTP -Wstrict-overflow"
 189     esac
 190     # -W[no-]strict-prototypes might be added by NTP_OPENSSL
 191 esac
 192
 193 NTP_OS_CFLAGS
 194
 195 ])dnl
 196 dnl ======================================================================