Remove the unneeded Hotspot features for building OpenJ9

OpenJ9 builds don't need to include support for the removed Hotspot
features:
`cds compiler1 compiler2 jni-check jvmci jvmti minimal nmt services
static-build vm-structs zero`
and all the gc's.

With this change configure shows:
`checking JVM features to use for variant 'server'... 'dtrace jfr
management'`

Signed-off-by: Peter Shipton <[email protected]>

closed/autoconf/custom-hook.m4

@@ -663,9 +663,6 @@ AC_DEFUN_ONCE([CUSTOM_LATE_HOOK],
   # Create the custom-spec.gmk
   AC_CONFIG_FILES([$OUTPUTDIR/custom-spec.gmk:$CLOSED_AUTOCONF_DIR/custom-spec.gmk.in])
 
-  # explicitly disable CDS archive generation (OpenJ9 does not support '-Xshare:dump')
-  BUILD_CDS_ARCHIVE=false
-
   # explicitly disable classlist generation
   ENABLE_GENERATE_CLASSLIST=false
 

closed/autoconf/custom-spec.gmk.in

@@ -182,9 +182,6 @@ $(foreach var, \
 J9JCL_SOURCES_DIR      := $(SUPPORT_OUTPUTDIR)/j9jcl
 J9JCL_SOURCES_DONEFILE := $(MAKESUPPORT_OUTPUTDIR)/j9jcl.done
 
-# Disable all hotspot features.
-JVM_FEATURES_server :=
-
 # Required by OpenJCEPlus.
 BUILD_OPENJCEPLUS  := @BUILD_OPENJCEPLUS@
 OPENJCEPLUS_TOPDIR := $(TOPDIR)/OpenJCEPlus

make/autoconf/jvm-features.m4

@@ -22,6 +22,9 @@
 # or visit www.oracle.com if you need additional information or have any
 # questions.
 #
+# ===========================================================================
+# (c) Copyright IBM Corp. 2024, 2024 All Rights Reserved
+# ===========================================================================
 
 ###############################################################################
 # Terminology used in this file:
@@ -44,9 +47,8 @@
 m4_define(jvm_features_valid, m4_normalize( \
     ifdef([custom_jvm_features_valid], custom_jvm_features_valid) \
     \
-    cds compiler1 compiler2 dtrace epsilongc g1gc jfr jni-check \
-    jvmci jvmti link-time-opt management minimal nmt opt-size parallelgc \
-    serialgc services shenandoahgc static-build vm-structs zero zgc \
+    dtrace jfr \
+    link-time-opt management opt-size \
 ))
 
 # Deprecated JVM features (these are ignored, but with a warning)
@@ -233,7 +235,10 @@ AC_DEFUN_ONCE([JVM_FEATURES_CHECK_CDS],
 [
   JVM_FEATURES_CHECK_AVAILABILITY(cds, [
     AC_MSG_CHECKING([if platform is supported by CDS])
-    if test "x$OPENJDK_TARGET_OS" = xaix; then
+    if true; then
+      AC_MSG_RESULT([no, OpenJ9])
+      AVAILABLE=false
+    elif test "x$OPENJDK_TARGET_OS" = xaix; then
       AC_MSG_RESULT([no, $OPENJDK_TARGET_OS-$OPENJDK_TARGET_CPU])
       AVAILABLE=false
     else
@@ -291,7 +296,10 @@ AC_DEFUN_ONCE([JVM_FEATURES_CHECK_JVMCI],
 [
   JVM_FEATURES_CHECK_AVAILABILITY(jvmci, [
     AC_MSG_CHECKING([if platform is supported by JVMCI])
-    if test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
+    if true; then
+      AC_MSG_RESULT([no, OpenJ9])
+      AVAILABLE=false
+    elif test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
       AC_MSG_RESULT([yes])
     elif test "x$OPENJDK_TARGET_CPU" = "xaarch64"; then
       AC_MSG_RESULT([yes])
@@ -309,7 +317,10 @@ AC_DEFUN_ONCE([JVM_FEATURES_CHECK_SHENANDOAHGC],
 [
   JVM_FEATURES_CHECK_AVAILABILITY(shenandoahgc, [
     AC_MSG_CHECKING([if platform is supported by Shenandoah])
-    if test "x$OPENJDK_TARGET_CPU_ARCH" = "xx86" || \
+    if true; then
+      AC_MSG_RESULT([no, OpenJ9])
+      AVAILABLE=false
+    elif test "x$OPENJDK_TARGET_CPU_ARCH" = "xx86" || \
         test "x$OPENJDK_TARGET_CPU" = "xaarch64" || \
         test "x$OPENJDK_TARGET_CPU" = "xppc64le" || \
         test "x$OPENJDK_TARGET_CPU" = "xriscv64"; then
@@ -344,7 +355,10 @@ AC_DEFUN_ONCE([JVM_FEATURES_CHECK_ZGC],
 [
   JVM_FEATURES_CHECK_AVAILABILITY(zgc, [
     AC_MSG_CHECKING([if platform is supported by ZGC])
-    if test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
+    if true; then
+      AC_MSG_RESULT([no, OpenJ9])
+      AVAILABLE=false
+    elif test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
       if test "x$OPENJDK_TARGET_OS" = "xlinux" || \
           test "x$OPENJDK_TARGET_OS" = "xwindows" || \
           test "x$OPENJDK_TARGET_OS" = "xmacosx"; then
@@ -543,10 +557,6 @@ AC_DEFUN([JVM_FEATURES_VERIFY],
     AC_MSG_ERROR([Specified JVM feature 'jvmti' requires feature 'services' for variant '$variant'])
   fi
 
-  if JVM_FEATURES_IS_ACTIVE(management) && ! JVM_FEATURES_IS_ACTIVE(nmt); then
-    AC_MSG_ERROR([Specified JVM feature 'management' requires feature 'nmt' for variant '$variant'])
-  fi
-
   # For backwards compatibility, disable a feature "globally" if one variant
   # is missing the feature.
   if ! JVM_FEATURES_IS_ACTIVE(cds); then
@@ -558,13 +568,6 @@ AC_DEFUN([JVM_FEATURES_VERIFY],
   if JVM_FEATURES_IS_ACTIVE(compiler2); then
     INCLUDE_COMPILER2="true"
   fi
-
-  # Verify that we have at least one gc selected (i.e., feature named "*gc").
-  if ! JVM_FEATURES_IS_ACTIVE(.*gc); then
-      AC_MSG_NOTICE([At least one gc needed for variant '$variant'.])
-      AC_MSG_NOTICE([Specified features: '$JVM_FEATURES_ACTIVE'])
-      AC_MSG_ERROR([Cannot continue])
-  fi
 ])
 
 ###############################################################################