add explicit use of -XX:+EnableJVMCI on command line or in jimage vm options

Author: dougxc

docs/reference-manual/embedding/embed-languages.md

@@ -415,15 +415,17 @@ This table shows the level of optimizations the Java runtimes currently provide:
 |-----------------------------------------------|---------------------------------------------------|
 | Oracle GraalVM                                | Optimized with additional compiler passes         |
 | GraalVM Community Edition                     | Optimized                                         |
-| Oracle JDK                                    | Optimized if enabled via experimental VM option   |
-| OpenJDK                                       | Optimized if enabled via experimental VM option   |
+| Oracle JDK                                    | Optimized via VM option                           |
+| OpenJDK                                       | Optimized via VM option and upgrade-module-path   |
 | JDK without JVMCI capability                  | No runtime optimizations (interpreter-only)       |
 
 ### Explanations
 
 * **Optimized:** Executed guest application code can be compiled and executed as highly efficient machine code at run time.
 * **Optimized with additional compiler passes:** Oracle GraalVM implements additional optimizations performed during runtime compilation. For example, it uses a more advanced inlining heuristic. This typically leads to better runtime performance and memory consumption.
-* **Optimized if enabled via experimental VM option:** Optimization is not enabled by default and must be enabled using `-XX:+EnableJVMCI` virtual machine option. In addition, to support compilation, the Graal compiler must be downloaded as a JAR file and put on the `--upgrade-module-path`. In this mode, the compiler runs as a Java application and may negatively affect the execution performance of the host application.
+* **Optimized via VM option:** Optimization is enabled by specifying `-XX:+EnableJVMCI` to the `java` launcher.
+* **Optimized via VM option and upgrade-module-path:** Optimization is enabled by specifying `-XX:+EnableJVMCI` to the `java` launcher.
+  In addition, the Graal compiler must be downloaded as a JAR file and put on the `--upgrade-module-path`. In this mode, the compiler runs as a Java application and may negatively affect the execution performance of the host application.
 * **No runtime optimizations:** With no runtime optimizations or if JVMCI is not enabled, the guest application code is executed in interpreter-only mode. 
 * **JVMCI:** Refers to the [Java-Level JVM Compiler Interface](https://openjdk.org/jeps/243) supported by most Java runtimes.
 

sdk/mx.sdk/mx_sdk.py

@@ -273,8 +273,7 @@ def __init__(self):
             # Oracle JDK includes the libjvmci compiler, allowing it to function as GraalVM.
             # However, the Graal compiler is disabled by default and must be explicitly enabled using the -XX:+UseJVMCICompiler option.
             graalvm_home = default_jdk.home
-            # GR-58388: Switch '-XX:+UseJVMCINativeLibrary' to '-XX:+UseGraalJIT'
-            additional_vm_args = ['-XX:+UnlockExperimentalVMOptions', '-XX:+EnableJVMCI', '-XX:+UseJVMCINativeLibrary', '-XX:-UnlockExperimentalVMOptions']
+            additional_vm_args = ['-XX:+UnlockExperimentalVMOptions', '-XX:+EnableJVMCI', '-XX:+UseGraalJIT', '-XX:-UnlockExperimentalVMOptions']
         else:
             graalvm_home = mx_sdk_vm.graalvm_home(fatalIfMissing=True)
             additional_vm_args = []

sdk/mx.sdk/mx_sdk_vm.py

@@ -776,6 +776,8 @@ def _get_image_vm_options(jdk, use_upgrade_module_path, modules, synthetic_modul
     if default_to_jvmci or 'jdk.graal.compiler' in non_synthetic_modules:
         threads = get_JVMCIThreadsPerNativeLibraryRuntime(jdk)
         vm_options.extend(['-XX:+UnlockExperimentalVMOptions', '-XX:+EnableJVMCIProduct'])
+        # As of JDK-8345826, the JVMCI module must be explicitly added to the root set
+        vm_options.append('-XX:+EnableJVMCI')
         if threads is not None and threads != 1:
             vm_options.append('-XX:JVMCIThreadsPerNativeLibraryRuntime=1')
         if default_to_jvmci == 'lib':
@@ -978,7 +980,7 @@ def jlink_new_jdk(jdk, dst_jdk_dir, module_dists, ignore_dists,
         jlink_persist = []
 
         if jdk_enables_jvmci_by_default(jdk):
-            # On JDK 9+, +EnableJVMCI forces jdk.internal.vm.ci to be in the root set
+            # +EnableJVMCI forces jdk.internal.vm.ci to be in the root set
             jlink += ['-J-XX:-EnableJVMCI', '-J-XX:-UseJVMCICompiler']
 
         jlink.append('--add-modules=' + ','.join(_get_image_root_modules(root_module_names, module_names, jdk_modules.keys(), use_upgrade_module_path)))

truffle/mx.truffle/mx_truffle.py

@@ -494,8 +494,13 @@ def _truffle_gate_runner(args, tasks):
 
 
 def gate_truffle_jvm(tasks):
-    if mx_sdk.GraalVMJDKConfig.is_libgraal_jdk(mx.get_jdk(tag='default').home):
+    default_jdk = mx.get_jdk(tag='default')
+    if mx_sdk.GraalVMJDKConfig.is_libgraal_jdk(default_jdk.home):
         additional_jvm_args = ['-XX:+UnlockExperimentalVMOptions', '-XX:+EnableJVMCI', '-XX:+UseJVMCINativeLibrary', '-XX:-UnlockExperimentalVMOptions']
+    elif default_jdk.javaCompliance >= '25':
+        # As of JDK-8345826, -XX:+EnableJVMCI must be on the command line
+        # to load the JVMCI module if libgraal is in use
+        additional_jvm_args = ['-XX:+EnableJVMCI']
     else:
         additional_jvm_args = []
     # GR-62632: Debug VM exception translation failure