| 1 | dnl @synopsis AC_PROG_CC_NO_WRITEABLE_STRINGS(substvar [,hard]) |
| 2 | dnl |
| 3 | dnl Try to find a compiler option that warns when a stringliteral is |
| 4 | dnl used in a place that could potentially modify the address. This |
| 5 | dnl should warn on giving an stringliteral to a function that asks of |
| 6 | dnl a non-const-modified char-pointer. |
| 7 | dnl |
| 8 | dnl The sanity check is done by looking at string.h which has a set |
| 9 | dnl of strcpy definitions that should be defined with const-modifiers |
| 10 | dnl to not emit a warning in all so many places. |
| 11 | dnl |
| 12 | dnl Currently this macro knows about GCC. |
| 13 | dnl hopefully will evolve to use: Solaris C compiler, |
| 14 | dnl Digital Unix C compiler, C for AIX Compiler, HP-UX C compiler, |
| 15 | dnl and IRIX C compiler. |
| 16 | dnl |
| 17 | dnl @version $Id: ac_prog_cc_no_writeable_strings.m4,v 1.1 2002/02/20 16:18:18 steve Exp $ |
| 18 | dnl @author Guido Draheim <guidod@gmx.de> |
| 19 | dnl |
| 20 | AC_DEFUN([AC_PROG_CC_NO_WRITEABLE_STRINGS], [ |
| 21 | pushdef([CV],ac_cv_prog_cc_no_writeable_strings)dnl |
| 22 | hard=$2 |
| 23 | if test -z "$hard"; then |
| 24 | msg="C to warn about writing to stringliterals" |
| 25 | else |
| 26 | msg="C to prohibit any write to stringliterals" |
| 27 | fi |
| 28 | AC_CACHE_CHECK($msg, CV, [ |
| 29 | cat > conftest.c <<EOF |
| 30 | #include <string.h> |
| 31 | int main (void) |
| 32 | { |
| 33 | char test[[16]]; |
| 34 | if (strcpy (test, "test")) return 0; |
| 35 | return 1; |
| 36 | } |
| 37 | EOF |
| 38 | dnl GCC |
| 39 | if test "$GCC" = "yes"; |
| 40 | then |
| 41 | if test -z "$hard"; then |
| 42 | CV="-Wwrite-strings" |
| 43 | else |
| 44 | CV="-fno-writable-strings -Wwrite-strings" |
| 45 | fi |
| 46 | |
| 47 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 48 | CV="suppressed: string.h" |
| 49 | fi |
| 50 | |
| 51 | dnl Solaris C compiler |
| 52 | elif $CC -flags 2>&1 | grep "Xc.*strict ANSI C" > /dev/null 2>&1 && |
| 53 | $CC -c -xstrconst conftest.c > /dev/null 2>&1 && |
| 54 | test -f conftest.o |
| 55 | then |
| 56 | # strings go into readonly segment |
| 57 | CV="-xstrconst" |
| 58 | |
| 59 | rm conftest.o |
| 60 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 61 | CV="suppressed: string.h" |
| 62 | fi |
| 63 | |
| 64 | dnl HP-UX C compiler |
| 65 | elif $CC > /dev/null 2>&1 && |
| 66 | $CC -c +ESlit conftest.c > /dev/null 2>&1 && |
| 67 | test -f conftest.o |
| 68 | then |
| 69 | # strings go into readonly segment |
| 70 | CV="+ESlit" |
| 71 | |
| 72 | rm conftest.o |
| 73 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 74 | CV="suppressed: string.h" |
| 75 | fi |
| 76 | |
| 77 | dnl Digital Unix C compiler |
| 78 | elif ! $CC > /dev/null 2>&1 && |
| 79 | $CC -c -readonly_strings conftest.c > /dev/null 2>&1 && |
| 80 | test -f conftest.o |
| 81 | then |
| 82 | # strings go into readonly segment |
| 83 | CV="-readonly_strings" |
| 84 | |
| 85 | rm conftest.o |
| 86 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 87 | CV="suppressed: string.h" |
| 88 | fi |
| 89 | |
| 90 | dnl C for AIX Compiler |
| 91 | |
| 92 | dnl IRIX C compiler |
| 93 | # -use_readonly_const is the default for IRIX C, |
| 94 | # puts them into .rodata, but they are copied later. |
| 95 | # need to be "-G0 -rdatashared" for strictmode but |
| 96 | # I am not sure what effect that has really. |
| 97 | |
| 98 | fi |
| 99 | rm -f conftest.* |
| 100 | ]) |
| 101 | if test -z "[$]$1" ; then |
| 102 | if test -n "$CV" ; then |
| 103 | case "$CV" in |
| 104 | suppressed*) $1="" ;; # known but suppressed |
| 105 | *) $1="$CV" ;; |
| 106 | esac |
| 107 | fi |
| 108 | fi |
| 109 | AC_SUBST($1) |
| 110 | popdef([CV])dnl |
| 111 | ]) |
| 112 | |
| 113 | |