Improve interaction between CRIU and CRaC configuration options

CRaC support requires CRIU support. If CRIU support is disabled
explicitly and CRaC is enabled explicitly, configuration will now
fail rather than incur a compile error later.

Otherwise, if CRaC support is requested explictly, CRIU support will
implicitly be enabled if that is not the default for CRIU.

Also, if CRIU support is explicitly disabled, CRaC will be implicitly
disabled if that is not the default for CRaC.

Signed-off-by: Keith W. Campbell <keithc@ca.ibm.com>

closed/autoconf/custom-hook.m4

@@ -40,8 +40,7 @@ AC_DEFUN_ONCE([CUSTOM_EARLY_HOOK],
   OPENJ9_PLATFORM_SETUP
   OPENJ9_CONFIGURE_CMAKE
   OPENJ9_CONFIGURE_COMPILERS
-  OPENJ9_CONFIGURE_CRAC_SUPPORT
-  OPENJ9_CONFIGURE_CRIU_SUPPORT
+  OPENJ9_CONFIGURE_CRAC_AND_CRIU_SUPPORT
   OPENJ9_CONFIGURE_CUDA
   OPENJ9_CONFIGURE_DDR
   OPENJ9_CONFIGURE_DEMOS
@@ -343,57 +342,86 @@ AC_DEFUN([OPENJ9_PLATFORM_EXTRACT_VARS_FROM_CPU],
   esac
 ])
 
-AC_DEFUN([OPENJ9_CONFIGURE_CRAC_SUPPORT],
+AC_DEFUN([OPENJ9_CONFIGURE_CRAC_AND_CRIU_SUPPORT],
 [
-  AC_MSG_CHECKING([for CRAC support])
-  AC_ARG_ENABLE([crac-support], [AS_HELP_STRING([--enable-crac-support], [enable CRAC support @<:@platform dependent@:>@])])
-  OPENJ9_ENABLE_CRAC_SUPPORT=false
+  AC_ARG_ENABLE([crac-support], [AS_HELP_STRING([--enable-crac-support], [enable CRaC support @<:@platform dependent@:>@])])
+  AC_ARG_ENABLE([criu-support], [AS_HELP_STRING([--enable-criu-support], [enable CRIU support @<:@platform dependent@:>@])])
+
+  # Complain about explicitly requested, but illegal combinations.
+  if test "x$enable_crac_support" = xyes && test "x$enable_criu_support" = xno ; then
+    AC_MSG_ERROR([--enable-crac-support requires CRIU support])
+  fi
+
+  # Compute platform-specific defaults.
+  case "$OPENJ9_PLATFORM_CODE" in
+    xa64)
+      default_crac=yes
+      default_criu=yes
+      ;;
+    xl64|xr64|xz64)
+      default_crac=no
+      default_criu=yes
+      ;;
+    *)
+      default_crac=no
+      default_criu=no
+      ;;
+  esac
 
+  # Capture the origin of each setting.
   if test "x$enable_crac_support" = xyes ; then
-    AC_MSG_RESULT([yes (explicitly enabled)])
-    OPENJ9_ENABLE_CRAC_SUPPORT=true
+    origin_crac="explicitly enabled"
   elif test "x$enable_crac_support" = xno ; then
-    AC_MSG_RESULT([no (explicitly disabled)])
+    origin_crac="explicitly disabled"
   elif test "x$enable_crac_support" = x ; then
-    case "$OPENJ9_PLATFORM_CODE" in
-      xa64)
-        AC_MSG_RESULT([yes (default)])
-        OPENJ9_ENABLE_CRAC_SUPPORT=true
-        ;;
-      *)
-        AC_MSG_RESULT([no (default)])
-        ;;
-    esac
+    # Adjust if CRUI is explicitly disabled.
+    if test "x$enable_criu_support" = xno && test "x$default_crac" = xyes ; then
+      origin_crac="implicitly disabled"
+      enable_crac_support=no
+    else
+      origin_crac=default
+      enable_crac_support=$default_crac
+    fi
   else
     AC_MSG_ERROR([--enable-crac-support accepts no argument])
   fi
-  AC_SUBST(OPENJ9_ENABLE_CRAC_SUPPORT)
-])
-
-AC_DEFUN([OPENJ9_CONFIGURE_CRIU_SUPPORT],
-[
-  AC_MSG_CHECKING([for CRIU support])
-  AC_ARG_ENABLE([criu-support], [AS_HELP_STRING([--enable-criu-support], [enable CRIU support @<:@platform dependent@:>@])])
-  OPENJ9_ENABLE_CRIU_SUPPORT=false
 
   if test "x$enable_criu_support" = xyes ; then
-    AC_MSG_RESULT([yes (explicitly enabled)])
-    OPENJ9_ENABLE_CRIU_SUPPORT=true
+    origin_criu="explicitly enabled"
   elif test "x$enable_criu_support" = xno ; then
-    AC_MSG_RESULT([no (explicitly disabled)])
+    origin_criu="explicitly disabled"
   elif test "x$enable_criu_support" = x ; then
-    case "$OPENJ9_PLATFORM_CODE" in
-      xa64|xl64|xr64|xz64)
-        AC_MSG_RESULT([yes (default)])
-        OPENJ9_ENABLE_CRIU_SUPPORT=true
-        ;;
-      *)
-        AC_MSG_RESULT([no (default)])
-        ;;
-    esac
+    # Adjust if CRaC is explicitly enabled.
+    if test "x$enable_crac_support" = xyes && test "x$default_criu" = xno ; then
+      origin_criu="implicitly enabled"
+      enable_criu_support=yes
+    else
+      origin_criu=default
+      enable_criu_support=$default_criu
+    fi
   else
     AC_MSG_ERROR([--enable-criu-support accepts no argument])
   fi
+
+  # Report and capture results.
+  AC_MSG_CHECKING([for CRAC support])
+  if test "x$enable_crac_support" = xyes ; then
+    AC_MSG_RESULT([yes ($origin_crac)])
+    OPENJ9_ENABLE_CRAC_SUPPORT=true
+  else
+    AC_MSG_RESULT([no ($origin_crac)])
+    OPENJ9_ENABLE_CRAC_SUPPORT=false
+  fi
+  AC_SUBST(OPENJ9_ENABLE_CRAC_SUPPORT)
+
+  AC_MSG_CHECKING([for CRIU support])
+  if test "x$enable_criu_support" = xyes ; then
+    AC_MSG_RESULT([yes ($origin_criu)])
+    OPENJ9_ENABLE_CRIU_SUPPORT=true
+  else
+    AC_MSG_RESULT([no ($origin_criu)])
+    OPENJ9_ENABLE_CRIU_SUPPORT=false
+  fi
   AC_SUBST(OPENJ9_ENABLE_CRIU_SUPPORT)
 ])