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

rev 49071 : 8198888: Reduce string allocation churn in InvokerBytecodeGenerator
Reviewed-by: psandoz, plevart

@@ -91,10 +91,14 @@
 
     /** ASM bytecode generation. */
     private ClassWriter cw;
     private MethodVisitor mv;
 
+    /** Single element internal class name lookup cache. */
+    private Class<?> lastClass;
+    private String lastInternalName;
+
     private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
     private static final Class<?> HOST_CLASS = LambdaForm.class;
 
     /** Main constructor; other constructors delegate to this one. */
     private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,

@@ -600,17 +604,22 @@
             throw new InternalError("unknown return type: " + type);
         }
         mv.visitInsn(opcode);
     }
 
-    private static String getInternalName(Class<?> c) {
+    private String getInternalName(Class<?> c) {
         if (c == Object.class)             return OBJ;
         else if (c == Object[].class)      return OBJARY;
         else if (c == Class.class)         return CLS;
         else if (c == MethodHandle.class)  return MH;
         assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
-        return c.getName().replace('.', '/');
+
+        if (c == lastClass) {
+            return lastInternalName;
+        }
+        lastClass = c;
+        return lastInternalName = c.getName().replace('.', '/');
     }
 
     private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
         MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
         MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder);