Fix configure to find arc4random via header files.

ISSUE:

On Ubuntu 12.04 LTS, arc4random is provided by libbsd.so, which is a
transitive dependency of libedit. If a system had libedit on it that
was implemented in terms of libbsd.so, then the arc4random test,
previously implemented as a linker test, would succeed with -ledit.
However, on Ubuntu this would also require a #include <bsd/stdlib.h>.
This caused a build breakage on configure-based Ubuntu 12.04 with
libedit installed.

FIX:

This fix changes configure to test for arc4random by searching for it
in the standard header files. On Ubuntu 12.04, this test now properly
fails to find arc4random as it is not defined in the default header
locations. It also tweaks the #define names to match the output of the
header check command, which is slightly different than the linker
function check #defines.

I tested the following scenarios:

(1) Ubuntu 12.04 without the libedit package [did not find arc4random,
as expected]

(2) Ubuntu 12.04 with libedit package [properly did not find
arc4random, as expected]

(3) Ubuntu 12.04 with most recent libedit, custom built, and not
dependent on libbsd.so [properly did not find arc4random, as
expected].

(4) FreeBSD 10.0B1 [properly found arc4random, as expected]

llvm-svn: 200819

autoconf/configure.ac

@@ -1757,13 +1757,16 @@ AC_CHECK_FUNCS([log log2 log10 exp exp2])
 AC_CHECK_FUNCS([getpagesize getrusage getrlimit setrlimit gettimeofday ])
 AC_CHECK_FUNCS([isatty mkdtemp mkstemp ])
 AC_CHECK_FUNCS([mktemp posix_spawn pread realpath sbrk setrlimit ])
-AC_CHECK_FUNCS([strerror strerror_r setenv arc4random ])
+AC_CHECK_FUNCS([strerror strerror_r setenv ])
 AC_CHECK_FUNCS([strtoll strtoq sysconf malloc_zone_statistics ])
 AC_CHECK_FUNCS([setjmp longjmp sigsetjmp siglongjmp writev])
 AC_CHECK_FUNCS([futimes futimens])
 AC_C_PRINTF_A
 AC_FUNC_RAND48
 
+dnl Check for arc4random accessible via AC_INCLUDES_DEFAULT.
+AC_CHECK_DECLS([arc4random])
+
 dnl Check the declaration "Secure API" on Windows environments.
 AC_CHECK_DECLS([strerror_s])
 

cmake/config-ix.cmake

@@ -117,7 +117,7 @@ if( NOT PURE_WINDOWS )
 endif()
 
 # function checks
-check_symbol_exists(arc4random "stdlib.h" HAVE_ARC4RANDOM)
+check_symbol_exists(arc4random "stdlib.h" HAVE_DECL_ARC4RANDOM)
 check_symbol_exists(backtrace "execinfo.h" HAVE_BACKTRACE)
 check_symbol_exists(getpagesize unistd.h HAVE_GETPAGESIZE)
 check_symbol_exists(getrusage sys/resource.h HAVE_GETRUSAGE)

configure

@@ -18527,8 +18527,7 @@ done
 
 
 
-
-for ac_func in strerror strerror_r setenv arc4random
+for ac_func in strerror strerror_r setenv
 do
 as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
 { echo "$as_me:$LINENO: checking for $ac_func" >&5
@@ -19161,6 +19160,93 @@ _ACEOF
 fi
 
 
+{ echo "$as_me:$LINENO: checking whether arc4random is declared" >&5
+echo $ECHO_N "checking whether arc4random is declared... $ECHO_C" >&6; }
+if test "${ac_cv_have_decl_arc4random+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+$ac_includes_default
+int
+main ()
+{
+#ifndef arc4random
+  char *p = (char *) arc4random;
+  return !p;
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest.$ac_objext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_have_decl_arc4random=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_cv_have_decl_arc4random=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_have_decl_arc4random" >&5
+echo "${ECHO_T}$ac_cv_have_decl_arc4random" >&6; }
+if test $ac_cv_have_decl_arc4random = yes; then
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_ARC4RANDOM 1
+_ACEOF
+
+
+else
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_ARC4RANDOM 0
+_ACEOF
+
+
+fi
+
+
+
 { echo "$as_me:$LINENO: checking whether strerror_s is declared" >&5
 echo $ECHO_N "checking whether strerror_s is declared... $ECHO_C" >&6; }
 if test "${ac_cv_have_decl_strerror_s+set}" = set; then

include/llvm/Config/config.h.in

@@ -33,9 +33,6 @@
 /* Directory where gcc is installed. */
 #undef GCC_INSTALL_PREFIX
 
-/* Define to 1 if you have the `arc4random' function. */
-#undef HAVE_ARC4RANDOM
-
 /* Define to 1 if you have the `argz_append' function. */
 #undef HAVE_ARGZ_APPEND
 
@@ -75,6 +72,10 @@
 /* Define to 1 if you have the <cxxabi.h> header file. */
 #undef HAVE_CXXABI_H
 
+/* Define to 1 if you have the declaration of `arc4random', and to 0 if you
+   don't. */
+#undef HAVE_DECL_ARC4RANDOM
+
 /* Define to 1 if you have the declaration of `FE_ALL_EXCEPT', and to 0 if you
    don't. */
 #undef HAVE_DECL_FE_ALL_EXCEPT

lib/Support/Unix/Process.inc

@@ -343,7 +343,7 @@ const char *Process::ResetColor() {
   return "\033[0m";
 }
 
-#if !defined(HAVE_ARC4RANDOM)
+#if !defined(HAVE_DECL_ARC4RANDOM) || !HAVE_DECL_ARC4RANDOM
 static unsigned GetRandomNumberSeed() {
   // Attempt to get the initial seed from /dev/urandom, if possible.
   if (FILE *RandomSource = ::fopen("/dev/urandom", "r")) {
@@ -364,7 +364,7 @@ static unsigned GetRandomNumberSeed() {
 #endif
 
 unsigned llvm::sys::Process::GetRandomNumber() {
-#if defined(HAVE_ARC4RANDOM)
+#if defined(HAVE_DECL_ARC4RANDOM) && HAVE_DECL_ARC4RANDOM
   return arc4random();
 #else
   static int x = (::srand(GetRandomNumberSeed()), 0);