RFR: 8264806: Remove the experimental JIT compiler [v2]

[Vladimir Kozlov]

On Sat, 10 Apr 2021 15:38:11 GMT, Igor Ignatyev <iignatyev at openjdk.org> wrote:

> should we remove `sun.hotspot.code.Compiler::isGraalEnabled` method and update a few of its users accordingly?
> what about `vm.graal.enabled` `@requires` property?

Thank you, @iignatev for looking on changes.

I forgot to mention that `Compiler::isGraalEnabled()` returns always false now. Because 94 tests uses `@requires !vm.graal.enabled` I don't want to include them in these changes which are already very big. I am not sure if I should modify tests if GraalVM group wants to run all these tests.

Unfortunately changes in `Compiler.java` are listed the last on `Files changed` tab and GitHub has trouble to load these big changes - it takes time to see them. Here `Compiler.java` chnges for review:
diff --git a/test/lib/sun/hotspot/code/Compiler.java b/test/lib/sun/hotspot/code/Compiler.java
index 99122bd93b8..71288ae4482 100644
--- a/test/lib/sun/hotspot/code/Compiler.java
+++ b/test/lib/sun/hotspot/code/Compiler.java
@@ -60,33 +60,10 @@ public class Compiler {
     /**
      * Check if Graal is used as JIT compiler.
      *
-     * Graal is enabled if following conditions are true:
-     * - we are not in Interpreter mode
-     * - UseJVMCICompiler flag is true
-     * - jvmci.Compiler variable is equal to 'graal'
-     * - TieredCompilation is not used or TieredStopAtLevel is greater than 3
-     * No need to check client mode because it set UseJVMCICompiler to false.
-     *
-     * @return true if Graal is used as JIT compiler.
+     * @return false because Graal is removed from JDK.
      */
     public static boolean isGraalEnabled() {
-        Boolean useCompiler = WB.getBooleanVMFlag("UseCompiler");
-        if (useCompiler == null || !useCompiler) {
-            return false;
-        }
-        Boolean useJvmciComp = WB.getBooleanVMFlag("UseJVMCICompiler");
-        if (useJvmciComp == null || !useJvmciComp) {
-            return false;
-        }
-
-        Boolean tieredCompilation = WB.getBooleanVMFlag("TieredCompilation");
-        Long compLevel = WB.getIntxVMFlag("TieredStopAtLevel");
-        // if TieredCompilation is enabled and compilation level is <= 3 then no Graal is used
-        if (tieredCompilation != null && tieredCompilation &&
-            compLevel != null && compLevel <= 3) {
-            return false;
-        }
-        return true;
+        return false;
     }
 ```

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PR: https://git.openjdk.java.net/jdk/pull/3421