382     int arity() {
 383         return arity;
 384     }
 385 
 386     /** Return the method type corresponding to my basic type signature. */
 387     MethodType methodType() {
 388         return signatureType(basicTypeSignature());
 389     }
 390     /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
 391     final String basicTypeSignature() {
 392         StringBuilder buf = new StringBuilder(arity() + 3);
 393         for (int i = 0, a = arity(); i < a; i++)
 394             buf.append(basicTypeChar(parameterType(i)));
 395         return buf.append('_').append(basicTypeChar(returnType())).toString();
 396     }
 397     static int signatureArity(String sig) {
 398         assert(isValidSignature(sig));
 399         return sig.indexOf('_');
 400     }
 401     static byte signatureReturn(String sig) {
 402         return basicType(sig.charAt(signatureArity(sig)+1));
 403     }
 404     static boolean isValidSignature(String sig) {
 405         int arity = sig.indexOf('_');
 406         if (arity < 0)  return false;  // must be of the form *_*
 407         int siglen = sig.length();
 408         if (siglen != arity + 2)  return false;  // *_X
 409         for (int i = 0; i < siglen; i++) {
 410             if (i == arity)  continue;  // skip '_'
 411             char c = sig.charAt(i);
 412             if (c == 'V')
 413                 return (i == siglen - 1 && arity == siglen - 2);
 414             if (BASIC_TYPE_CHARS.indexOf(c) < 0)  return false; // must be [LIJFD]
 415         }
 416         return true;  // [LIJFD]*_[LIJFDV]
 417     }
 418     static MethodType signatureType(String sig) {
 419         Class<?>[] ptypes = new Class<?>[signatureArity(sig)];
 420         for (int i = 0; i < ptypes.length; i++)
 421             ptypes[i] = basicTypeClass(basicType(sig.charAt(i)));
 422         Class<?> rtype = basicTypeClass(signatureReturn(sig));

 500         }
 501         LambdaForm prep = getPreparedForm(basicTypeSignature());
 502         this.vmentry = prep.vmentry;
 503         // TO DO: Maybe add invokeGeneric, invokeWithArguments
 504     }
 505 
 506     /** Generate optimizable bytecode for this form. */
 507     MemberName compileToBytecode() {
 508         MethodType invokerType = methodType();
 509         assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
 510         if (vmentry != null && isCompiled) {
 511             return vmentry;  // already compiled somehow
 512         }
 513         try {
 514             vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
 515             if (TRACE_INTERPRETER)
 516                 traceInterpreter("compileToBytecode", this);
 517             isCompiled = true;
 518             return vmentry;
 519         } catch (Error | Exception ex) {
 520             throw newInternalError("compileToBytecode", ex);
 521         }
 522     }
 523 
 524     private static final ConcurrentHashMap<String,LambdaForm> PREPARED_FORMS;
 525     static {
 526         int   capacity   = 512;    // expect many distinct signatures over time
 527         float loadFactor = 0.75f;  // normal default
 528         int   writers    = 1;
 529         PREPARED_FORMS = new ConcurrentHashMap<>(capacity, loadFactor, writers);
 530     }
 531 
 532     private static Map<String,LambdaForm> computeInitialPreparedForms() {
 533         // Find all predefined invokers and associate them with canonical empty lambda forms.
 534         HashMap<String,LambdaForm> forms = new HashMap<>();
 535         for (MemberName m : MemberName.getFactory().getMethods(LambdaForm.class, false, null, null, null)) {
 536             if (!m.isStatic() || !m.isPackage())  continue;
 537             MethodType mt = m.getMethodType();
 538             if (mt.parameterCount() > 0 &&
 539                 mt.parameterType(0) == MethodHandle.class &&
 540                 m.getName().startsWith("interpret_")) {

 382     int arity() {
 383         return arity;
 384     }
 385 
 386     /** Return the method type corresponding to my basic type signature. */
 387     MethodType methodType() {
 388         return signatureType(basicTypeSignature());
 389     }
 390     /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
 391     final String basicTypeSignature() {
 392         StringBuilder buf = new StringBuilder(arity() + 3);
 393         for (int i = 0, a = arity(); i < a; i++)
 394             buf.append(basicTypeChar(parameterType(i)));
 395         return buf.append('_').append(basicTypeChar(returnType())).toString();
 396     }
 397     static int signatureArity(String sig) {
 398         assert(isValidSignature(sig));
 399         return sig.indexOf('_');
 400     }
 401     static byte signatureReturn(String sig) {
 402         return basicType(sig.charAt(signatureArity(sig) + 1));
 403     }
 404     static boolean isValidSignature(String sig) {
 405         int arity = sig.indexOf('_');
 406         if (arity < 0)  return false;  // must be of the form *_*
 407         int siglen = sig.length();
 408         if (siglen != arity + 2)  return false;  // *_X
 409         for (int i = 0; i < siglen; i++) {
 410             if (i == arity)  continue;  // skip '_'
 411             char c = sig.charAt(i);
 412             if (c == 'V')
 413                 return (i == siglen - 1 && arity == siglen - 2);
 414             if (BASIC_TYPE_CHARS.indexOf(c) < 0)  return false; // must be [LIJFD]
 415         }
 416         return true;  // [LIJFD]*_[LIJFDV]
 417     }
 418     static MethodType signatureType(String sig) {
 419         Class<?>[] ptypes = new Class<?>[signatureArity(sig)];
 420         for (int i = 0; i < ptypes.length; i++)
 421             ptypes[i] = basicTypeClass(basicType(sig.charAt(i)));
 422         Class<?> rtype = basicTypeClass(signatureReturn(sig));

 500         }
 501         LambdaForm prep = getPreparedForm(basicTypeSignature());
 502         this.vmentry = prep.vmentry;
 503         // TO DO: Maybe add invokeGeneric, invokeWithArguments
 504     }
 505 
 506     /** Generate optimizable bytecode for this form. */
 507     MemberName compileToBytecode() {
 508         MethodType invokerType = methodType();
 509         assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
 510         if (vmentry != null && isCompiled) {
 511             return vmentry;  // already compiled somehow
 512         }
 513         try {
 514             vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
 515             if (TRACE_INTERPRETER)
 516                 traceInterpreter("compileToBytecode", this);
 517             isCompiled = true;
 518             return vmentry;
 519         } catch (Error | Exception ex) {
 520             throw newInternalError("compileToBytecode: " + this, ex);
 521         }
 522     }
 523 
 524     private static final ConcurrentHashMap<String,LambdaForm> PREPARED_FORMS;
 525     static {
 526         int   capacity   = 512;    // expect many distinct signatures over time
 527         float loadFactor = 0.75f;  // normal default
 528         int   writers    = 1;
 529         PREPARED_FORMS = new ConcurrentHashMap<>(capacity, loadFactor, writers);
 530     }
 531 
 532     private static Map<String,LambdaForm> computeInitialPreparedForms() {
 533         // Find all predefined invokers and associate them with canonical empty lambda forms.
 534         HashMap<String,LambdaForm> forms = new HashMap<>();
 535         for (MemberName m : MemberName.getFactory().getMethods(LambdaForm.class, false, null, null, null)) {
 536             if (!m.isStatic() || !m.isPackage())  continue;
 537             MethodType mt = m.getMethodType();
 538             if (mt.parameterCount() > 0 &&
 539                 mt.parameterType(0) == MethodHandle.class &&
 540                 m.getName().startsWith("interpret_")) {