[scripts] Add mechanism to select the Zero interpreter

Author: JakubVanek

scripts/build.sh

@@ -18,7 +18,7 @@ bash "$AUTOGEN_PATH"
 # Disable GUI:                 --enable-headless-only
 # Help to find freetype:       --with-freetype-lib=/usr/lib/arm-linux-gnueabi
 #                              --with-freetype-include=/usr/include
-# Build only the Client VM:    --with-jvm-variants=client
+# Build only the right VM:     --with-jvm-variants=client
 # Add extra build flags:       --with-extra-cflags="-w -Wno-error -D__SOFTFP__"
 #                              --with-extra-cxxflags="-w -Wno-error -D__SOFTFP__"
 #   - Fix the build on new GCC: -w -Wno-error
@@ -36,7 +36,7 @@ bash ./configure --with-boot-jdk="$HOSTJDK" \
                  --enable-headless-only \
                  --with-freetype-lib=/usr/lib/arm-linux-gnueabi \
                  --with-freetype-include=/usr/include \
-                 --with-jvm-variants=client \
+                 --with-jvm-variants="$HOTSPOT_VARIANT" \
                  --with-extra-cflags="-w -Wno-error -D__SOFTFP__" \
                  --with-extra-cxxflags="-w -Wno-error -D__SOFTFP__" \
                  --with-version-string="$JAVA_VERSION" \

scripts/config.sh

@@ -12,14 +12,42 @@ IMAGEDIR="/build/jdk/build/linux-arm-normal-client-release/images"
 HOSTJDK="$SCRIPTDIR/jdk-10"
 
 
+# Version-specific configuration
+
+# mercurial repository
+#JAVA_REPO="http://hg.openjdk.java.net/jdk-updates/jdkXu/"
+# patch to apply
+#PATCHVER="jdkX"
+# path to autogen.sh to regenerate the build system
+#AUTOGEN_PATH="./common/autoconf/autogen.sh"
+# hotspot variant to use
+#HOTSPOT_VARIANT=client
+# A comment from OpenJDK build system sums it up pretty well:
+##   server: normal interpreter, and a tiered C1/C2 compiler
+##   client: normal interpreter, and C1 (no C2 compiler)
+##   minimal: reduced form of client with optional features stripped out
+##   core: normal interpreter only, no compiler
+##   zero: C++ based interpreter only, no compiler
+##   custom: baseline JVM with no default features
+# 'client' JVM starts fast enough and provides the best performance.
+# 'zero' JVM provides us with a fallback when ARMv5 sflt JIT stops working completely.
+
+
+# OpenJDK 9
 if [ "$JDKVER" -eq "9" ]; then
   JAVA_REPO="http://hg.openjdk.java.net/jdk-updates/jdk9u/"
   PATCHVER="jdk9"
   AUTOGEN_PATH="./common/autoconf/autogen.sh"
+  HOTSPOT_VARIANT=client
+
+# OpenJDK 10
 elif [ "$JDKVER" -eq "10" ]; then
   JAVA_REPO="http://hg.openjdk.java.net/jdk-updates/jdk10u/"
   PATCHVER="jdk10"
   AUTOGEN_PATH="./make/autoconf/autogen.sh"
+  HOTSPOT_VARIANT=client
+
+# invalid or unset version
 else
   echo "Error! Please specify JDK version to compile via the JDKVER environment variable." >&2
   echo "Acceptable values:" >&2