[GR-8577] Introduce EagerJVMCI flag to force eager JVMCI initialization.

PullRequest: graal-jvmci-8/40

Author: dougxc

jvmci/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotJVMCIRuntime.java

@@ -70,6 +70,12 @@ static class DelayedInit {
         static {
             try (InitTimer t = timer("HotSpotJVMCIRuntime.<init>")) {
                 instance = new HotSpotJVMCIRuntime();
+
+                // Can only do eager initialization of the JVMCI compiler
+                // once the singleton instance is available.
+                if (instance.config.getFlag("EagerJVMCI", Boolean.class)) {
+                    instance.getCompiler();
+                }
             }
         }
     }

src/share/vm/compiler/compileBroker.cpp

@@ -944,8 +944,9 @@ void CompileBroker::compilation_init(TRAPS) {
 #if INCLUDE_JVMCI
   if (EnableJVMCI) {
     JVMCICompiler* jvmci = new JVMCICompiler();
-    if (JVMCIPrintProperties) {
-      // Initialize JVMCI eagerly if JVMCIPrintProperties is enabled.
+    if (EagerJVMCI || JVMCIPrintProperties) {
+      // Initialize JVMCI eagerly when it is explicitly requested
+      // or if JVMCIPrintProperties is enabled.
       // The JVMCI Java initialization code will read this flag and
       // do the printing if it's set.
       JVMCIRuntime::ensure_jvmci_class_loader_is_initialized();

src/share/vm/jvmci/jvmciCompilerToVM.cpp

@@ -284,6 +284,7 @@ objArrayHandle CompilerToVM::initialize_intrinsics(TRAPS) {
   do_intx_flag(HugeMethodLimit)                                            \
   do_bool_flag(Inline)                                                     \
   do_intx_flag(JVMCICounterSize)                                           \
+  do_bool_flag(EagerJVMCI)                                                 \
   do_bool_flag(JVMCIPrintProperties)                                       \
   do_bool_flag(JVMCIUseFastLocking)                                        \
   do_intx_flag(MethodProfileWidth)                                         \

src/share/vm/jvmci/jvmci_globals.cpp

@@ -151,6 +151,16 @@ bool JVMCIGlobals::check_jvmci_flags_are_consistent() {
     }
     FLAG_SET_DEFAULT(EnableJVMCI, true);
   }
+
+  if (!EnableJVMCI) {
+    // Switch off eager JVMCI initialization if JVMCI is disabled.
+    // To simplify testing, don't throw error if EagerJVMCI is set.
+    if (EagerJVMCI) {
+      FLAG_SET_DEFAULT(EagerJVMCI, false);
+    }
+  }
+  JVMCI_FLAG_CHECKED(EagerJVMCI)
+
   CHECK_NOT_SET(UseJVMCIClassLoader,          EnableJVMCI)
   CHECK_NOT_SET(CodeInstallSafepointChecks,   EnableJVMCI)
   CHECK_NOT_SET(JVMCITraceLevel,              EnableJVMCI)

src/share/vm/jvmci/jvmci_globals.hpp

@@ -66,6 +66,9 @@
   product(bool, PrintBootstrap, true,                                       \
           "Print JVMCI bootstrap progress and summary")                     \
                                                                             \
+  product(bool, EagerJVMCI, false,                                          \
+          "Force eager initialization of the JVMCI compiler")               \
+                                                                            \
   product(intx, JVMCIThreads, 1,                                            \
           "Force number of JVMCI compiler threads to use")                  \
                                                                             \