contrib/ntp/sntp/m4/ntp_compiler.m4

   1 dnl ######################################################################
   2 dnl Common m4sh code for compiler stuff
   3 AC_DEFUN([NTP_COMPILER], [
   4
   5 AC_USE_SYSTEM_EXTENSIONS
   6
   7 # Ralf Wildenhues: With per-target flags we need CC_C_O
   8 # AM_PROG_CC_C_O supersets AC_PROG_CC_C_O
   9 AM_PROG_CC_C_O
  10 AC_PROG_GCC_TRADITIONAL
  11 AC_REQUIRE([AC_PROG_CC_STDC])
  12 dnl AC_REQUIRE([AC_PROG_CC_C89])
  13 dnl AC_REQUIRE([AC_PROG_CC_C99])
  14
  15 CFLAGS_NTP=
  16 CPPFLAGS_NTP=
  17 LDADD_NTP=
  18 LDFLAGS_NTP=
  19 AC_SUBST([CFLAGS_NTP])
  20 AC_SUBST([CPPFLAGS_NTP])
  21 AC_SUBST([LDADD_NTP])
  22 AC_SUBST([LDFLAGS_NTP])
  23
  24 case "$ac_cv_prog_cc_c89" in
  25  no)
  26     AC_MSG_WARN([ANSI C89/ISO C90 is the minimum to compile NTP]
  27                 [ version 4.2.5 and higher.])
  28     ;;
  29 esac
  30
  31 AC_CACHE_CHECK(
  32     [if $CC can handle @%:@warning],
  33     [ntp_cv_cpp_warning],
  34     [AC_COMPILE_IFELSE(
  35         [AC_LANG_PROGRAM([[]], [[#warning foo]])],
  36         [ntp_cv_cpp_warning=yes],
  37         [ntp_cv_cpp_warning=no]
  38     )]
  39 )
  40 case "$ntp_cv_cpp_warning" in
  41  no)
  42     AC_DEFINE([NO_OPTION_NAME_WARNINGS], [1],
  43         [Should we avoid @%:@warning on option name collisions?])
  44 esac
  45
  46 AC_CACHE_CHECK(
  47     [if $CC supports __attribute__((...))],
  48     [ntp_cv_cc_attribute],
  49     [AC_COMPILE_IFELSE(
  50         [AC_LANG_PROGRAM(
  51             [[]],
  52             [[void foo(void) __attribute__((__noreturn__));]]
  53             )],
  54         [ntp_cv_cc_attribute=yes],
  55         [ntp_cv_cc_attribute=no]
  56     )]
  57 )
  58 case "$ntp_cv_cc_attribute" in
  59  yes)
  60     AC_DEFINE([HAVE___ATTRIBUTE__], [],
  61         [defined if C compiler supports __attribute__((...))])
  62 esac
  63 AH_VERBATIM(
  64     [HAVE___ATTRIBUTE___VERBATIM],
  65     [
  66         /* define away __attribute__() if unsupported */
  67         #ifndef HAVE___ATTRIBUTE__
  68         # define __attribute__(x) /* empty */
  69         #endif
  70         #define ISC_PLATFORM_NORETURN_PRE
  71         #define ISC_PLATFORM_NORETURN_POST __attribute__((__noreturn__))
  72     ]
  73 )
  74
  75 case "$GCC" in
  76  yes)
  77     SAVED_CFLAGS="$CFLAGS"
  78     CFLAGS="$CFLAGS -Wstrict-overflow"
  79     AC_CACHE_CHECK(
  80         [if $CC can handle -Wstrict-overflow],
  81         [ntp_cv_gcc_Wstrict_overflow],
  82         [AC_COMPILE_IFELSE(
  83             [AC_LANG_PROGRAM([[]], [[]])],
  84             [ntp_cv_gcc_Wstrict_overflow=yes],
  85             [ntp_cv_gcc_Wstrict_overflow=no]
  86         )       ]
  87     )
  88     #
  89     # $ntp_cv_gcc_Wstrict_overflow is tested later to add the
  90     # flag to CFLAGS.
  91     #
  92     CFLAGS="$SAVED_CFLAGS -Winit-self"
  93     AC_CACHE_CHECK(
  94         [if $CC can handle -Winit-self],
  95         [ntp_cv_gcc_Winit_self],
  96         [
  97             AC_COMPILE_IFELSE(
  98                 [AC_LANG_PROGRAM([[]], [[]])],
  99                 [ntp_cv_gcc_Winit_self=yes],
 100                 [ntp_cv_gcc_Winit_self=no]
 101             )
 102         ]
 103     )
 104     CFLAGS="$SAVED_CFLAGS"
 105     AS_UNSET([SAVED_CFLAGS])
 106     #
 107     # $ntp_cv_gcc_Winit_self is tested later to add the
 108     # flag to CFLAGS_NTP.
 109     #
 110     AC_CACHE_CHECK(
 111         [if linker supports omitting unused code and data],
 112         [ntp_cv_gc_sections_runs],
 113         [
 114             dnl  NetBSD will link but likely not run with --gc-sections
 115             dnl  http://bugs.ntp.org/1844
 116             dnl  http://gnats.netbsd.org/40401
 117             dnl  --gc-sections causes attempt to load as linux elf, with
 118             dnl  wrong syscalls in place.  Test a little gauntlet of
 119             dnl  simple stdio read code checking for errors, expecting
 120             dnl  enough syscall differences that the NetBSD code will
 121             dnl  fail even with Linux emulation working as designed.
 122             dnl  A shorter test could be refined by someone with access
 123             dnl  to a NetBSD host with Linux emulation working.
 124             origCFLAGS="$CFLAGS"
 125             CFLAGS="$CFLAGS -Wl,--gc-sections"
 126             AC_LINK_IFELSE(
 127                 [AC_LANG_PROGRAM(
 128                     [[
 129                         #include <stdlib.h>
 130                         #include <stdio.h>
 131                     ]],
 132                     [[
 133                         FILE *  fpC;
 134                         char    buf[32];
 135                         size_t  cch;
 136                         int     read_success_once;
 137
 138                         fpC = fopen("conftest.c", "r");
 139                         if (NULL == fpC)
 140                                 exit(1);
 141                         do {
 142                                 cch = fread(buf, sizeof(buf), 1, fpC);
 143                                 read_success_once |= (0 != cch);
 144                         } while (0 != cch);
 145                         if (!read_success_once)
 146                                 exit(2);
 147                         if (!feof(fpC))
 148                                 exit(3);
 149                         if (0 != fclose(fpC))
 150                                 exit(4);
 151
 152                         exit(EXIT_SUCCESS);
 153                     ]]
 154                 )],
 155                 [
 156                     if test "X$cross_compiling" = "Xyes" || grep gc-sections conftest.err ; then
 157                         ntp_cv_gc_sections_runs=no
 158                     else
 159                         ntp_cv_gc_sections_runs=no
 160                         ./conftest >/dev/null 2>&1 && ntp_cv_gc_sections_runs=yes
 161                     fi
 162                 ],
 163                 [ntp_cv_gc_sections_runs=no]
 164             )
 165             CFLAGS="$origCFLAGS"
 166             AS_UNSET([origCFLAGS])
 167         ]
 168     )
 169     case "$ntp_cv_gc_sections_runs" in
 170      yes)
 171         LDADD_LIBNTP="-Wl,--gc-sections"
 172         CFLAGS_NTP="$CFLAGS_NTP -ffunction-sections -fdata-sections"
 173         ;;
 174      no)
 175         LDADD_LIBNTP=
 176         ;;
 177     esac
 178     CFLAGS_NTP="$CFLAGS_NTP -Wall"
 179     CFLAGS_NTP="$CFLAGS_NTP -Wcast-align"
 180     CFLAGS_NTP="$CFLAGS_NTP -Wcast-qual"
 181     # CFLAGS_NTP="$CFLAGS_NTP -Wconversion"
 182     # CFLAGS_NTP="$CFLAGS_NTP -Werror"
 183     # CFLAGS_NTP="$CFLAGS_NTP -Wextra"
 184     # CFLAGS_NTP="$CFLAGS_NTP -Wfloat-equal"
 185     CFLAGS_NTP="$CFLAGS_NTP -Wmissing-prototypes"
 186     CFLAGS_NTP="$CFLAGS_NTP -Wpointer-arith"
 187     CFLAGS_NTP="$CFLAGS_NTP -Wshadow"
 188     # CFLAGS_NTP="$CFLAGS_NTP -Wtraditional"
 189     # CFLAGS_NTP="$CFLAGS_NTP -Wwrite-strings"
 190     case "$ntp_cv_gcc_Winit_self" in
 191      yes)
 192         CFLAGS_NTP="$CFLAGS_NTP -Winit-self"
 193     esac
 194     case "$ntp_cv_gcc_Wstrict_overflow" in
 195      yes)
 196         CFLAGS_NTP="$CFLAGS_NTP -Wstrict-overflow"
 197     esac
 198     # -W[no-]strict-prototypes might be added by NTP_OPENSSL
 199 esac
 200
 201 NTP_OS_CFLAGS
 202
 203 AC_C_BIGENDIAN
 204 AC_C_VOLATILE
 205 AC_PROG_CPP
 206
 207 ])dnl
 208 dnl ======================================================================