Merge pull request #20 from hppritcha/upstream_pr1997

Protect against LTO optimizer

config/prte_check_cflags.m4

@@ -2,7 +2,7 @@ dnl -*- shell-script -*-
 dnl
 dnl Copyright (c) 2021 IBM Corporation.  All rights reserved.
 dnl
-dnl Copyright (c) 2021      Nanook Consulting.  All rights reserved.
+dnl Copyright (c) 2021-2024 Nanook Consulting  All rights reserved.
 dnl $COPYRIGHT$
 dnl
 dnl Additional copyrights may follow
@@ -40,3 +40,15 @@ AC_MSG_CHECKING(if $CC supports ([$1]))
                 AC_MSG_RESULT([yes])
             fi
 ])
+
+
+AC_DEFUN([_PRTE_CHECK_LTO_FLAG], [
+    chkflg=`echo $1 | grep -- -flto`
+    if test -n "$chkflg"; then
+        AC_MSG_WARN([Configure has detected the presence of the -flto])
+        AC_MSG_WARN([compiler directive in $2. PRRTE does not currently])
+        AC_MSG_WARN([support this flag as it conflicts with the])
+        AC_MSG_WARN([plugin architecture of the PRRTE code base.])
+        AC_MSG_ERROR([Please remove this directive and re-run configure.])
+    fi
+])

configure.ac

@@ -931,6 +931,19 @@ CPPFLAGS="$CPP_INCLUDES $CPPFLAGS $PRTE_FINAL_CPPFLAGS"
 LDFLAGS="$LDFLAGS $PRTE_FINAL_LDFLAGS"
 LIBS="$LIBS $PRTE_FINAL_LIBS"
 
+
+# We do not currently support the "lto" optimizer as it
+# aggregates all the headers from our plugins, resulting
+# in a configuration that generates warnings/errors when
+# passed through their optimizer phase. We therefore check
+# for the flag, and if found, output a message explaining
+# the situation and aborting configure
+_PRTE_CHECK_LTO_FLAG($CPPFLAGS, CPPFLAGS)
+_PRTE_CHECK_LTO_FLAG($CFLAGS, CFLAGS)
+_PRTE_CHECK_LTO_FLAG($LDFLAGS, LDFLAGS)
+_PRTE_CHECK_LTO_FLAG($LIBS, LIBS)
+
+
 # restore any user-provided Werror flags
 AS_IF([test ! -z "$PRTE_CFLAGS_cache"], [CFLAGS="$CFLAGS $PRTE_CFLAGS_cache"])