Configure: adjusted optimization level for Sun C. With "-fast" (and with "-xbuiltin=%all -xO4"), Sun C miscompiles ngx_http_script_add_copy_code(), which is inlined into ngx_http_script_compile(). From the assembly code it looks like the code uses uninitialized register when calculating new p value after memcpy: movq %r15,%rdi call _memcpy leaq (%r15,rbx),%rax movq (%r12),%rbx movb $0x0000000000000000,(%rax) Note that %rax is set to (%r15 + %rbx), but %rbx is only set after it is used. As such, "*p = '\0'" tries to modify an unrelated memory address, leading to a segmentation fault. The issue was seen in tests which use null-terminated complex values: proxy_ssl_certificate_vars.t, uwsgi_ssl_certificate_vars.t, stream_proxy_ssl_certificate_vars.t. Tested with Sun C compilers from Sun Studio 12.3, 12.4, 12.5, and 12.6. Restructuring code, such as splitting ngx_cpymem() with a separate "p += value->len" increment, fixes things, but it is not clear if its the only place where such miscompilation can happen. Fix is to use "-fast -xO3". Since IPO requires "-xO5", it is commented out.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


echo $ngx_n "checking for system byte ordering ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for system byte ordering

END


cat << END > $NGX_AUTOTEST.c

int main(void) {
    int i = 0x11223344;
    char *p;

    p = (char *) &i;
    if (*p == 0x44) return 0;
    return 1;
}

END

ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
          -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"

eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"

if [ -x $NGX_AUTOTEST ]; then
    if $NGX_AUTOTEST >/dev/null 2>&1; then
        echo " little endian"
        have=NGX_HAVE_LITTLE_ENDIAN . auto/have
    else
        echo " big endian"
    fi

    rm -rf $NGX_AUTOTEST*

else
    rm -rf $NGX_AUTOTEST*

    echo
    echo "$0: error: cannot detect system byte ordering"
    exit 1
fi