build: Cache build mode for components

Create cache variables for component build mode (dso vs. static).
We have a use case for components knowing how other components are
built (specifically, components that depend on a common component),
and this is a generic way of exposing that.

At the same time, slowly start trying to be more safe about variable
usage in the macros, using the Autoconf polymorphic variable functions
where possible.

Signed-off-by: Brian Barrett <[email protected]>

Author: bwbarrett

config/opal_mca.m4

@@ -12,8 +12,7 @@ dnl Copyright (c) 2004-2005 The Regents of the University of California.
 dnl                         All rights reserved.
 dnl Copyright (c) 2010-2021 Cisco Systems, Inc.  All rights reserved
 dnl Copyright (c) 2013-2017 Intel, Inc. All rights reserved.
-dnl Copyright (c) 2018-2021 Amazon.com, Inc. or its affiliates.
-dnl                         All Rights reserved.
+dnl Copyright (c) 2018-2022 Amazon.com, Inc. or its affiliates.  All Rights reserved.
 dnl Copyright (c) 2021      Triad National Security, LLC. All rights
 dnl                         reserved.
 dnl $COPYRIGHT$
@@ -604,9 +603,7 @@ AC_DEFUN([MCA_CONFIGURE_M4_CONFIG_COMPONENT],[
     MCA_COMPONENT_BUILD_CHECK($1, $2, $3, [should_build=$8], [should_build=0])
     # Allow the component to override the build mode if it really wants to.
     # It is, of course, free to end up calling MCA_COMPONENT_COMPILE_MODE
-    m4_ifdef([MCA_$1_$2_$3_COMPILE_MODE],
-             [MCA_$1_$2_$3_COMPILE_MODE($1, $2, $3, compile_mode)],
-             [MCA_COMPONENT_COMPILE_MODE($1, $2, $3, compile_mode)])
+    MCA_COMPONENT_COMPILE_MODE([$1], [$2], [$3], [compile_mode])
 
     # try to configure the component
     m4_ifdef([MCA_$1_$2_$3_CONFIG],
@@ -706,10 +703,52 @@ AC_DEFUN([MCA_CONFIGURE_ALL_CONFIG_COMPONENTS],[
 # MCA_COMPONENT_COMPILE_MODE(project_name (1), framework_name (2),
 #                            component_name (3), compile_mode_variable (4))
 # -------------------------------------------------------------------------
-# set compile_mode_variable to the compile mode for the given component
+# set compile_mode_variable to the compile mode for the given component.
+# this macro will only evaluate the build mode once per configure, returning
+# the cached value for subsequent tests.  The string is not stored in a cache
+# variable (ie .*_cv_.*) because cache variables would not be invalidated
+# based on changes to --enable-mca-dso or --enable-mca-static.
 #
 #   NOTE: component_name may not be determined until runtime....
 AC_DEFUN([MCA_COMPONENT_COMPILE_MODE],[
+    OAC_ASSERT_LITERAL([$1], [1])dnl
+    OAC_ASSERT_LITERAL([$2], [2])dnl
+
+    AS_VAR_PUSHDEF([compile_mode_cv], [$1_$2_$3_compile_mode])dnl
+    AS_VAR_SET_IF([compile_mode_cv],
+        [],
+	[AS_LITERAL_IF([$3],
+             [m4_ifdef([MCA_$1_$2_$3_COMPILE_MODE],
+                  [dnl We introduced caching of this check after setting the compile
+                   dnl mode by the substitute macro was common, and there was not a
+                   dnl polymorphic variable assumption in all those macros, so we use
+                   dnl a temporary with a fixed name.
+                   OPAL_VAR_SCOPE_PUSH([component_compile_mode_tmp])
+                   MCA_$1_$2_$3_COMPILE_MODE([$1], [$2], [$3], [component_compile_mode_tmp])
+                   AS_VAR_COPY([compile_mode_cv], [$component_compile_mode_tmp])
+                   OPAL_VAR_SCOPE_POP],
+                  [MCA_COMPONENT_COMPILE_MODE_INTERNAL([$1], [$2], [$3], [compile_mode_cv])])],
+             [MCA_COMPONENT_COMPILE_MODE_INTERNAL([$1], [$2], [$3], [compile_mode_cv])])])
+    AS_VAR_COPY([$4], [compile_mode_cv])
+    AS_VAR_POPDEF([compile_mode_cv])dnl
+])
+
+# MCA_COMPONENT_COMPILE_MODE_INTERNAL(project_name (1), framework_name (2),
+#                            component_name (3), compile_mode_variable (4))
+# -------------------------------------------------------------------------
+# Determine compile mode of the given component.  Prefer a static
+# build by default.  Users can customize build mode by influencing the
+# component, framework, or all-up build flags.  This function starts
+# at the most specific (component) and works its way out, looking for
+# a set option.
+#
+# Components can avoid calling this function by defining a macro
+# MCA_<project>_<framework>_<component>_COMPILE_MODE.
+#
+#   NOTE: component_name may not be determined until runtime....
+AC_DEFUN([MCA_COMPONENT_COMPILE_MODE_INTERNAL], [
+    OPAL_VAR_SCOPE_PUSH([compile_mode_internal_tmp SHARED_FRAMEWORK SHARED_COMPONENT STATIC_FRAMEWORK STATIC_COMPONENT])
+
     SHARED_FRAMEWORK="$DSO_$2"
     AS_VAR_COPY([SHARED_COMPONENT], [DSO_$2_$3])
 
@@ -720,27 +759,31 @@ AC_DEFUN([MCA_COMPONENT_COMPILE_MODE],[
     # there is a tie (either neither or both specified), prefer
     # static.
     if test "$STATIC_COMPONENT" = "1"; then
-        $4=static
+        compile_mode_internal_tmp=static
     elif test "$SHARED_COMPONENT" = "1"; then
-        $4=dso
+        compile_mode_internal_tmp=dso
     elif test "$STATIC_FRAMEWORK" = "1"; then
-        $4=static
+        compile_mode_internal_tmp=static
     elif test "$SHARED_FRAMEWORK" = "1"; then
-        $4=dso
+        compile_mode_internal_tmp=dso
     elif test "$STATIC_all" = "1"; then
-        $4=static
+        compile_mode_internal_tmp=static
     elif test "$DSO_all" = "1"; then
-        $4=dso
+        compile_mode_internal_tmp=dso
     else
-        $4=static
+        compile_mode_internal_tmp=static
     fi
 
+    AS_VAR_SET([$4], [$compile_mode_internal_tmp])
+
     AC_MSG_CHECKING([for MCA component $2:$3 compile mode])
     if test "$DIRECT_$2" = "$3" ; then
-        AC_MSG_RESULT([$$4 - direct])
+        AC_MSG_RESULT([$compile_mode_internal_tmp - direct])
     else
-        AC_MSG_RESULT([$$4])
+        AC_MSG_RESULT([$compile_mode_internal_tmp])
     fi
+
+    OPAL_VAR_SCOPE_POP
 ])
 
 # OPAL_MCA_STRIP_LAFILES(output_variable(1),