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

*** 63,72 ****
--- 63,73 ----
  
      private static final String OBJ     = "java/lang/Object";
      private static final String CLASS_PREFIX   = "java/lang/invoke/LambdaForm$Value$";
      private static final String DEFAULT_CLASS  = "MH";
      private static final String LL_SIG  = "(L" + OBJ + ";)L" + OBJ + ";";
+     private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
  
      private static final String MH           = "java/lang/invoke/MethodHandle";
      private static final String MHARY2       = "[[L" + MH + ";";
  
      static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
*** 92,102 ****
--- 93,121 ----
      LambdaFormBuilder(LambdaFormCodeBuilder builder, LambdaForm lambdaForm) {
          this.builder = builder;
          this.lambdaForm = lambdaForm;
      }
  
+     /** Generates code to check that actual receiver and LambdaForm matches */
+     private boolean checkActualReceiver() {
+         // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
+         builder.dup().load(0).invokestatic(MethodHandleImpl.class, "assertSame", LLV_SIG, false);
+         return true;
+     }
+ 
      void generateLambdaFormBody() {
+         if (lambdaForm.customized != null && MethodHandleBuilder.ENABLE_POOL_PATCHES) {
+             // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
+             // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
+             // It enables more efficient code generation in some situations, since embedded constants
+             // are compile-time constants for JIT compiler.
+             builder.ldc(lambdaForm.customized)
+                    .checkcast(MethodHandle.class);
+             assert(checkActualReceiver()); // generates runtime check
+             builder.store(0);
+         }
+ 
          // iterate over the form's names, generating bytecode instructions for each
          // start iterating at the first name following the arguments
          Name onStack = null;
          for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
              Name name = lambdaForm.names[i];