8357979: Compile jdk.internal.vm.ci targeting the Boot JDK version

Reviewed-by: erikj, dnsimon

make/CompileJavaModules.gmk

@@ -115,6 +115,7 @@ $(eval $(call SetupJavaCompilation, $(MODULE), \
     EXCLUDE_FILES := $(EXCLUDE_FILES), \
     EXCLUDE_PATTERNS := -files, \
     KEEP_ALL_TRANSLATIONS := $(KEEP_ALL_TRANSLATIONS), \
+    TARGET_RELEASE := $(TARGET_RELEASE), \
     JAVAC_FLAGS := \
         $(DOCLINT) \
         $(JAVAC_FLAGS) \

make/autoconf/boot-jdk.m4

@@ -395,11 +395,9 @@ AC_DEFUN_ONCE([BOOTJDK_SETUP_BOOT_JDK],
 
   # When compiling code to be executed by the Boot JDK, force compatibility with the
   # oldest supported bootjdk.
-  OLDEST_BOOT_JDK=`$ECHO $DEFAULT_ACCEPTABLE_BOOT_VERSIONS \
+  OLDEST_BOOT_JDK_VERSION=`$ECHO $DEFAULT_ACCEPTABLE_BOOT_VERSIONS \
       | $TR " " "\n" | $SORT -n | $HEAD -n1`
-  # -Xlint:-options is added to avoid "warning: [options] system modules path not set in conjunction with -source"
-  BOOT_JDK_SOURCETARGET="-source $OLDEST_BOOT_JDK -target $OLDEST_BOOT_JDK -Xlint:-options"
-  AC_SUBST(BOOT_JDK_SOURCETARGET)
+  AC_SUBST(OLDEST_BOOT_JDK_VERSION)
 
   # Check if the boot jdk is 32 or 64 bit
   if $JAVA -version 2>&1 | $GREP -q "64-Bit"; then

make/autoconf/spec.gmk.template

@@ -393,9 +393,8 @@ EXTERNAL_BUILDJDK := @EXTERNAL_BUILDJDK@
 # Whether the boot jdk jar supports --date=TIMESTAMP
 BOOT_JDK_JAR_SUPPORTS_DATE := @BOOT_JDK_JAR_SUPPORTS_DATE@
 
-# When compiling Java source to be run by the boot jdk
-# use these extra flags, eg -source 6 -target 6
-BOOT_JDK_SOURCETARGET := @BOOT_JDK_SOURCETARGET@
+# The oldest supported boot jdk version
+OLDEST_BOOT_JDK_VERSION := @OLDEST_BOOT_JDK_VERSION@
 
 # Information about the build system
 NUM_CORES := @NUM_CORES@

make/common/JavaCompilation.gmk

@@ -38,10 +38,15 @@ include JarArchive.gmk
 ###
 
 # Create classes that can run on the bootjdk
-TARGET_RELEASE_BOOTJDK := $(BOOT_JDK_SOURCETARGET)
+# -Xlint:-options is added to avoid the warning
+# "system modules path not set in conjunction with -source"
+TARGET_RELEASE_BOOTJDK := -source $(OLDEST_BOOT_JDK_VERSION) \
+    -target $(OLDEST_BOOT_JDK_VERSION) -Xlint:-options
 
-# Create classes that can be used in (or be a part of) the new jdk we're building
-TARGET_RELEASE_NEWJDK := -source $(JDK_SOURCE_TARGET_VERSION) -target $(JDK_SOURCE_TARGET_VERSION)
+# Create classes that can be used in (or be a part of) the new jdk we're
+# building
+TARGET_RELEASE_NEWJDK := -source $(JDK_SOURCE_TARGET_VERSION) \
+    -target $(JDK_SOURCE_TARGET_VERSION)
 
 # Create classes that can be used in JDK 8, for legacy support
 TARGET_RELEASE_JDK8 := --release 8

make/modules/jdk.internal.vm.ci/Java.gmk

@@ -33,4 +33,6 @@ DISABLED_WARNINGS_java += dangling-doc-comments this-escape
 
 JAVAC_FLAGS += -parameters -XDstringConcat=inline
 
+TARGET_RELEASE := $(TARGET_RELEASE_BOOTJDK)
+
 ################################################################################