wip Stable and unique Lambda and LambdaForm class names

Author: ThanHenderson

src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java

@@ -163,7 +163,16 @@ public InnerClassLambdaMetafactory(MethodHandles.Lookup caller,
         implMethodName = implInfo.getName();
         implMethodDesc = implInfo.getMethodType().toMethodDescriptorString();
         constructorType = invokedType.changeReturnType(Void.TYPE);
-        lambdaClassName = targetClass.getName().replace('.', '/') + "$$Lambda$" + counter.incrementAndGet();
+        int uniqueID = targetClass.getName().hashCode()
+                        ^ invokedType.toString().hashCode()
+                        ^ samMethodName.hashCode()
+                        ^ samMethodType.toString().hashCode()
+                        ^ instantiatedMethodType.toString().hashCode()
+                        ^ implMethodClassName.hashCode()
+                        ^ implMethodName.hashCode()
+                        ^ implMethodDesc.hashCode();
+        uniqueID &= 0x7fffffff;
+        lambdaClassName = targetClass.getName().replace('.', '/') + "$$Lambda$" + uniqueID;
         cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
         int parameterCount = invokedType.parameterCount();
         if (parameterCount > 0) {
@@ -252,6 +261,10 @@ public Constructor<?>[] run() {
      * is not found
      */
     private Class<?> spinInnerClass() throws LambdaConversionException {
+        Class<?> innerClass = MethodHandleNatives.findInSCC(lambdaClassName, targetClass);
+        if (innerClass != null) {
+            return innerClass;
+        }
         String[] interfaces;
         String samIntf = samBase.getName().replace('.', '/');
         boolean accidentallySerializable = !isSerializable && Serializable.class.isAssignableFrom(samBase);

src/java.base/share/classes/java/lang/invoke/InvokerBytecodeGenerator.java

@@ -38,6 +38,9 @@
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.lang.invoke.LambdaForm.BasicType;
+import java.lang.invoke.LambdaForm.Name;
+import java.lang.invoke.LambdaForm.NamedFunction;
 import java.lang.reflect.Modifier;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -111,7 +114,12 @@ private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
         if (DUMP_CLASS_FILES) {
             className = makeDumpableClassName(className);
         }
-        this.className  = className;
+        int uniqueID = lambdaForm.toString().hashCode()
+                        ^ className.hashCode()
+                        ^ invokerName.hashCode()
+                        ^ invokerType.toString().hashCode();
+        uniqueID &= 0x7fffffff;
+        this.className = className + "$" + uniqueID;
         this.lambdaForm = lambdaForm;
         this.invokerName = invokerName;
         this.invokerType = invokerType;
@@ -690,6 +698,10 @@ static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType
         if (pregenerated != null)  return pregenerated; // pre-generated bytecode
 
         InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
+        Class<?> customized = MethodHandleNatives.findInSCC(CLASS_PREFIX + g.className, HOST_CLASS);
+        if (customized != null) {
+            return resolveInvokerMember(customized, g.invokerName, g.invokerType);
+        }
         return g.loadMethod(g.generateCustomizedCodeBytes());
     }
 
@@ -1766,6 +1778,10 @@ static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
         MethodType type = mt;  // includes leading argument
         type = type.changeParameterType(0, MethodHandle.class);
         InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
+        Class<?> customized = MethodHandleNatives.findInSCC(CLASS_PREFIX + g.className, HOST_CLASS);
+        if (customized != null) {
+            return resolveInvokerMember(customized, g.invokerName, g.invokerType);
+        }
         return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
     }
 
@@ -1825,6 +1841,10 @@ static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
         MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
         String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
         InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
+        Class<?> customized = MethodHandleNatives.findInSCC(CLASS_PREFIX + g.className, HOST_CLASS);
+        if (customized != null) {
+            return resolveInvokerMember(customized, g.invokerName, g.invokerType);
+        }
         return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
     }
 

src/java.base/share/classes/java/lang/invoke/MethodHandleNatives.java

@@ -49,6 +49,7 @@ private MethodHandleNatives() { } // static only
 
     static native void init(MemberName self, Object ref);
     static native void expand(MemberName self);
+    static native Class<?> findInSCC(String classname, Class<?> hostClass);
     static native MemberName resolve(MemberName self, Class<?> caller,
             boolean speculativeResolve) throws LinkageError, ClassNotFoundException;
     static native int getMembers(Class<?> defc, String matchName, String matchSig,