[skip ci] add UseGraalJIT VM flag

Author: dougxc

src/hotspot/share/jvmci/jvmci_globals.hpp

@@ -48,6 +48,14 @@ class fileStream;
   product(bool, EnableJVMCI, false, EXPERIMENTAL,                           \
           "Enable JVMCI")                                                   \
                                                                             \
+  product(bool, UseGraalJIT, false,                                         \
+          "Select the Graal JVMCI compiler. This is a macro for: "          \
+          "  -XX:+UnlockExperimentalVMOptions "                             \
+          "  -XX:+EnableJVMCIProduct "                                      \
+          "  -XX:+UseJVMCICompiler "                                        \
+          "  -Djvmci.Compiler=graal "                                       \
+          "  -XX:-UnlockExperimentalVMOptions")                             \
+                                                                            \
   product(bool, EnableJVMCIProduct, false, EXPERIMENTAL,                    \
           "Allow JVMCI to be used in product mode. This alters a subset of "\
           "JVMCI flags to be non-experimental, defaults UseJVMCICompiler "  \

src/hotspot/share/runtime/arguments.cpp

@@ -2827,10 +2827,35 @@ jint Arguments::parse_each_vm_init_arg(const JavaVMInitArgs* args, bool* patch_m
         return JNI_ERR;
 #endif // INCLUDE_MANAGEMENT
 #if INCLUDE_JVMCI
+    } else if (match_option(option, "-XX:-UseGraalJIT")) {
+      FLAG_SET_CMDLINE(UseJVMCICompiler, false);
+    } else if (match_option(option, "-XX:+UseGraalJIT")) {
+      if (!EnableJVMCIProduct) {
+        bool save = UnlockExperimentalVMOptions;
+        bool ok = JVMCIGlobals::enable_jvmci_product_mode(origin);
+        UnlockExperimentalVMOptions = save;
+        if (!ok) {
+          jio_fprintf(defaultStream::error_stream(),
+            "Unable to enable JVMCI in product mode");
+          return JNI_ERR;
+        }
+      }
+
+      const char* jvmci_compiler = get_property("jvmci.Compiler");
+      if (jvmci_compiler != nullptr) {
+        if (strcmp(jvmci_compiler, "graal") != 0) {
+          jio_fprintf(defaultStream::error_stream(),
+            "Value of jvmci.Compiler incompatible with +UseGraalJIT: %s", jvmci_compiler);
+          return JNI_ERR;
+        }
+      } else if (!add_property("jvmci.Compiler=graal")) {
+          return JNI_ENOMEM;
+      }
+      FLAG_SET_CMDLINE(UseJVMCICompiler, true);
     } else if (match_option(option, "-XX:-EnableJVMCIProduct")) {
       if (EnableJVMCIProduct) {
         jio_fprintf(defaultStream::error_stream(),
-                  "-XX:-EnableJVMCIProduct cannot come after -XX:+EnableJVMCIProduct\n");
+                  "-XX:-EnableJVMCIProduct cannot come after -XX:+EnableJVMCIProduct or -XX:+UseGraalJIT\n");
         return JNI_EINVAL;
       }
     } else if (match_option(option, "-XX:+EnableJVMCIProduct")) {