better detection of broken -fzero-call-used-regs

Use OSSH_CHECK_CFLAG_LINK() for detection of these flags and extend
test program to exercise varargs, which seems to catch more stuff.

ok dtucker@

diff --git a/configure.ac b/configure.ac
index 36e1028e128a094de632195bb021aa60682fa8cb..379cd746b92e35b62400c90ebc85a2eafdb8785e 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -234,9 +234,9 @@ if test "$GCC" = "yes" || test "$GCC" = "egcs"; then
        # clang 17 has a different bug that causes an ICE when using this
        # flag at all (https://bugzilla.mindrot.org/show_bug.cgi?id=3629)
        case "$CLANG_VER" in
-       apple-15*) OSSH_CHECK_CFLAG_COMPILE([-fzero-call-used-regs=used]) ;;
+       apple-15*) OSSH_CHECK_CFLAG_LINK([-fzero-call-used-regs=used]) ;;
        17*)    ;;
-       *)      OSSH_CHECK_CFLAG_COMPILE([-fzero-call-used-regs=used]) ;;
+       *)      OSSH_CHECK_CFLAG_LINK([-fzero-call-used-regs=used]) ;;
        esac
        OSSH_CHECK_CFLAG_COMPILE([-ftrivial-auto-var-init=zero])
     fi

diff --git a/m4/openssh.m4 b/m4/openssh.m4
index 6a1fa9b0e1f624f75f2e4ef8adddd77387a867ff..5d4c56280fce211715eb6aa72eb5beddb301d4c3 100644 (file)
--- a/m4/openssh.m4
+++ b/m4/openssh.m4
@@ -6,13 +6,23 @@ dnl behaviours.
 AC_DEFUN([OSSH_COMPILER_FLAG_TEST_PROGRAM],
        [AC_LANG_SOURCE([[
 #include <stdlib.h>
+#include <stdarg.h>
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 /* Trivial function to help test for -fzero-call-used-regs */
 int f(int n) {return rand() % n;}
+char *f2(char *s, ...) {
+       char ret[64];
+       va_list args;
+       va_start(args, s);
+       vsnprintf(ret, sizeof(ret), s, args);
+       va_end(args);
+       return strdup(ret);
+}
 int main(int argc, char **argv) {
        (void)argv;
-       char b[256];
+       char b[256], *cp;
        /* Some math to catch -ftrapv problems in the toolchain */
        int i = 123 * argc, j = 456 + argc, k = 789 - argc;
        float l = i * 2.1;
@@ -21,6 +31,8 @@ int main(int argc, char **argv) {
        f(1);
        snprintf(b, sizeof b, "%d %d %d %f %f %lld %lld\n", i,j,k,l,m,n,o);
        if (write(1, b, 0) == -1) exit(0);
+       cp = f2("%d %d %d %f %f %lld %lld\n", i,j,k,l,m,n,o);
+       free(cp);
        /*
         * Test fallthrough behaviour.  clang 10's -Wimplicit-fallthrough does
         * not understand comments and we don't use the "fallthrough" attribute