1 /*
   2  * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.lang.invoke;
  27 
  28 import jdk.internal.perf.PerfCounter;
  29 import jdk.internal.vm.annotation.DontInline;
  30 import jdk.internal.vm.annotation.Stable;
  31 import sun.invoke.util.Wrapper;
  32 
  33 import java.lang.annotation.ElementType;
  34 import java.lang.annotation.Retention;
  35 import java.lang.annotation.RetentionPolicy;
  36 import java.lang.annotation.Target;
  37 import java.lang.reflect.Method;
  38 import java.util.Arrays;
  39 import java.util.HashMap;
  40 
  41 import static java.lang.invoke.LambdaForm.BasicType.*;
  42 import static java.lang.invoke.MethodHandleNatives.Constants.REF_invokeStatic;
  43 import static java.lang.invoke.MethodHandleStatics.*;
  44 
  45 /**
  46  * The symbolic, non-executable form of a method handle's invocation semantics.
  47  * It consists of a series of names.
  48  * The first N (N=arity) names are parameters,
  49  * while any remaining names are temporary values.
  50  * Each temporary specifies the application of a function to some arguments.
  51  * The functions are method handles, while the arguments are mixes of
  52  * constant values and local names.
  53  * The result of the lambda is defined as one of the names, often the last one.
  54  * <p>
  55  * Here is an approximate grammar:
  56  * <blockquote><pre>{@code
  57  * LambdaForm = "(" ArgName* ")=>{" TempName* Result "}"
  58  * ArgName = "a" N ":" T
  59  * TempName = "t" N ":" T "=" Function "(" Argument* ");"
  60  * Function = ConstantValue
  61  * Argument = NameRef | ConstantValue
  62  * Result = NameRef | "void"
  63  * NameRef = "a" N | "t" N
  64  * N = (any whole number)
  65  * T = "L" | "I" | "J" | "F" | "D" | "V"
  66  * }</pre></blockquote>
  67  * Names are numbered consecutively from left to right starting at zero.
  68  * (The letters are merely a taste of syntax sugar.)
  69  * Thus, the first temporary (if any) is always numbered N (where N=arity).
  70  * Every occurrence of a name reference in an argument list must refer to
  71  * a name previously defined within the same lambda.
  72  * A lambda has a void result if and only if its result index is -1.
  73  * If a temporary has the type "V", it cannot be the subject of a NameRef,
  74  * even though possesses a number.
  75  * Note that all reference types are erased to "L", which stands for {@code Object}.
  76  * All subword types (boolean, byte, short, char) are erased to "I" which is {@code int}.
  77  * The other types stand for the usual primitive types.
  78  * <p>
  79  * Function invocation closely follows the static rules of the Java verifier.
  80  * Arguments and return values must exactly match when their "Name" types are
  81  * considered.
  82  * Conversions are allowed only if they do not change the erased type.
  83  * <ul>
  84  * <li>L = Object: casts are used freely to convert into and out of reference types
  85  * <li>I = int: subword types are forcibly narrowed when passed as arguments (see {@code explicitCastArguments})
  86  * <li>J = long: no implicit conversions
  87  * <li>F = float: no implicit conversions
  88  * <li>D = double: no implicit conversions
  89  * <li>V = void: a function result may be void if and only if its Name is of type "V"
  90  * </ul>
  91  * Although implicit conversions are not allowed, explicit ones can easily be
  92  * encoded by using temporary expressions which call type-transformed identity functions.
  93  * <p>
  94  * Examples:
  95  * <blockquote><pre>{@code
  96  * (a0:J)=>{ a0 }
  97  *     == identity(long)
  98  * (a0:I)=>{ t1:V = System.out#println(a0); void }
  99  *     == System.out#println(int)
 100  * (a0:L)=>{ t1:V = System.out#println(a0); a0 }
 101  *     == identity, with printing side-effect
 102  * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
 103  *                 t3:L = BoundMethodHandle#target(a0);
 104  *                 t4:L = MethodHandle#invoke(t3, t2, a1); t4 }
 105  *     == general invoker for unary insertArgument combination
 106  * (a0:L, a1:L)=>{ t2:L = FilterMethodHandle#filter(a0);
 107  *                 t3:L = MethodHandle#invoke(t2, a1);
 108  *                 t4:L = FilterMethodHandle#target(a0);
 109  *                 t5:L = MethodHandle#invoke(t4, t3); t5 }
 110  *     == general invoker for unary filterArgument combination
 111  * (a0:L, a1:L)=>{ ...(same as previous example)...
 112  *                 t5:L = MethodHandle#invoke(t4, t3, a1); t5 }
 113  *     == general invoker for unary/unary foldArgument combination
 114  * (a0:L, a1:I)=>{ t2:I = identity(long).asType((int)->long)(a1); t2 }
 115  *     == invoker for identity method handle which performs i2l
 116  * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
 117  *                 t3:L = Class#cast(t2,a1); t3 }
 118  *     == invoker for identity method handle which performs cast
 119  * }</pre></blockquote>
 120  * <p>
 121  * @author John Rose, JSR 292 EG
 122  */
 123 class LambdaForm {
 124     final int arity;
 125     final int result;
 126     final boolean forceInline;
 127     final MethodHandle customized;
 128     @Stable final Name[] names;
 129     final Kind kind;
 130     MemberName vmentry;   // low-level behavior, or null if not yet prepared
 131     private boolean isCompiled;
 132 
 133     // Either a LambdaForm cache (managed by LambdaFormEditor) or a link to uncustomized version (for customized LF)
 134     volatile Object transformCache;
 135 
 136     public static final int VOID_RESULT = -1, LAST_RESULT = -2;
 137 
 138     enum BasicType {
 139         L_TYPE('L', Object.class, Wrapper.OBJECT),  // all reference types
 140         I_TYPE('I', int.class,    Wrapper.INT),
 141         J_TYPE('J', long.class,   Wrapper.LONG),
 142         F_TYPE('F', float.class,  Wrapper.FLOAT),
 143         D_TYPE('D', double.class, Wrapper.DOUBLE),  // all primitive types
 144         V_TYPE('V', void.class,   Wrapper.VOID);    // not valid in all contexts
 145 
 146         static final BasicType[] ALL_TYPES = BasicType.values();
 147         static final BasicType[] ARG_TYPES = Arrays.copyOf(ALL_TYPES, ALL_TYPES.length-1);
 148 
 149         static final int ARG_TYPE_LIMIT = ARG_TYPES.length;
 150         static final int TYPE_LIMIT = ALL_TYPES.length;
 151 
 152         final char btChar;
 153         final Class<?> btClass;
 154         final Wrapper btWrapper;
 155 
 156         private BasicType(char btChar, Class<?> btClass, Wrapper wrapper) {
 157             this.btChar = btChar;
 158             this.btClass = btClass;
 159             this.btWrapper = wrapper;
 160         }
 161 
 162         char basicTypeChar() {
 163             return btChar;
 164         }
 165         Class<?> basicTypeClass() {
 166             return btClass;
 167         }
 168         Wrapper basicTypeWrapper() {
 169             return btWrapper;
 170         }
 171         int basicTypeSlots() {
 172             return btWrapper.stackSlots();
 173         }
 174 
 175         static BasicType basicType(byte type) {
 176             return ALL_TYPES[type];
 177         }
 178         static BasicType basicType(char type) {
 179             switch (type) {
 180                 case 'L': return L_TYPE;
 181                 case 'I': return I_TYPE;
 182                 case 'J': return J_TYPE;
 183                 case 'F': return F_TYPE;
 184                 case 'D': return D_TYPE;
 185                 case 'V': return V_TYPE;
 186                 // all subword types are represented as ints
 187                 case 'Z':
 188                 case 'B':
 189                 case 'S':
 190                 case 'C':
 191                     return I_TYPE;
 192                 default:
 193                     throw newInternalError("Unknown type char: '"+type+"'");
 194             }
 195         }
 196         static BasicType basicType(Wrapper type) {
 197             char c = type.basicTypeChar();
 198             return basicType(c);
 199         }
 200         static BasicType basicType(Class<?> type) {
 201             if (!type.isPrimitive())  return L_TYPE;
 202             return basicType(Wrapper.forPrimitiveType(type));
 203         }
 204         static BasicType[] basicTypes(String types) {
 205             BasicType[] btypes = new BasicType[types.length()];
 206             for (int i = 0; i < btypes.length; i++) {
 207                 btypes[i] = basicType(types.charAt(i));
 208             }
 209             return btypes;
 210         }
 211         static String basicTypeDesc(BasicType[] types) {
 212             if (types == null) {
 213                 return null;
 214             }
 215             if (types.length == 0) {
 216                 return "";
 217             }
 218             StringBuilder sb = new StringBuilder();
 219             for (BasicType bt : types) {
 220                 sb.append(bt.basicTypeChar());
 221             }
 222             return sb.toString();
 223         }
 224         static int[] basicTypeOrds(BasicType[] types) {
 225             if (types == null) {
 226                 return null;
 227             }
 228             int[] a = new int[types.length];
 229             for(int i = 0; i < types.length; ++i) {
 230                 a[i] = types[i].ordinal();
 231             }
 232             return a;
 233         }
 234 
 235         static char basicTypeChar(Class<?> type) {
 236             return basicType(type).btChar;
 237         }
 238 
 239         static byte[] basicTypesOrd(Class<?>[] types) {
 240             byte[] ords = new byte[types.length];
 241             for (int i = 0; i < ords.length; i++) {
 242                 ords[i] = (byte)basicType(types[i]).ordinal();
 243             }
 244             return ords;
 245         }
 246 
 247         static boolean isBasicTypeChar(char c) {
 248             return "LIJFDV".indexOf(c) >= 0;
 249         }
 250         static boolean isArgBasicTypeChar(char c) {
 251             return "LIJFD".indexOf(c) >= 0;
 252         }
 253 
 254         static { assert(checkBasicType()); }
 255         private static boolean checkBasicType() {
 256             for (int i = 0; i < ARG_TYPE_LIMIT; i++) {
 257                 assert ARG_TYPES[i].ordinal() == i;
 258                 assert ARG_TYPES[i] == ALL_TYPES[i];
 259             }
 260             for (int i = 0; i < TYPE_LIMIT; i++) {
 261                 assert ALL_TYPES[i].ordinal() == i;
 262             }
 263             assert ALL_TYPES[TYPE_LIMIT - 1] == V_TYPE;
 264             assert !Arrays.asList(ARG_TYPES).contains(V_TYPE);
 265             return true;
 266         }
 267     }
 268 
 269     enum Kind {
 270         GENERIC("invoke"),
 271         ZERO("zero"),
 272         IDENTITY("identity"),
 273         BOUND_REINVOKER("BMH.reinvoke", "reinvoke"),
 274         REINVOKER("MH.reinvoke", "reinvoke"),
 275         DELEGATE("MH.delegate", "delegate"),
 276         EXACT_LINKER("MH.invokeExact_MT", "invokeExact_MT"),
 277         EXACT_INVOKER("MH.exactInvoker", "exactInvoker"),
 278         GENERIC_LINKER("MH.invoke_MT", "invoke_MT"),
 279         GENERIC_INVOKER("MH.invoker", "invoker"),
 280         LINK_TO_TARGET_METHOD("linkToTargetMethod"),
 281         LINK_TO_CALL_SITE("linkToCallSite"),
 282         DIRECT_INVOKE_VIRTUAL("DMH.invokeVirtual", "invokeVirtual"),
 283         DIRECT_INVOKE_SPECIAL("DMH.invokeSpecial", "invokeSpecial"),
 284         DIRECT_INVOKE_STATIC("DMH.invokeStatic", "invokeStatic"),
 285         DIRECT_NEW_INVOKE_SPECIAL("DMH.newInvokeSpecial", "newInvokeSpecial"),
 286         DIRECT_INVOKE_INTERFACE("DMH.invokeInterface", "invokeInterface"),
 287         DIRECT_INVOKE_STATIC_INIT("DMH.invokeStaticInit", "invokeStaticInit"),
 288         GET_OBJECT("getObject"),
 289         PUT_OBJECT("putObject"),
 290         GET_OBJECT_VOLATILE("getObjectVolatile"),
 291         PUT_OBJECT_VOLATILE("putObjectVolatile"),
 292         GET_INT("getInt"),
 293         PUT_INT("putInt"),
 294         GET_INT_VOLATILE("getIntVolatile"),
 295         PUT_INT_VOLATILE("putIntVolatile"),
 296         GET_BOOLEAN("getBoolean"),
 297         PUT_BOOLEAN("putBoolean"),
 298         GET_BOOLEAN_VOLATILE("getBooleanVolatile"),
 299         PUT_BOOLEAN_VOLATILE("putBooleanVolatile"),
 300         GET_BYTE("getByte"),
 301         PUT_BYTE("putByte"),
 302         GET_BYTE_VOLATILE("getByteVolatile"),
 303         PUT_BYTE_VOLATILE("putByteVolatile"),
 304         GET_CHAR("getChar"),
 305         PUT_CHAR("putChar"),
 306         GET_CHAR_VOLATILE("getCharVolatile"),
 307         PUT_CHAR_VOLATILE("putCharVolatile"),
 308         GET_SHORT("getShort"),
 309         PUT_SHORT("putShort"),
 310         GET_SHORT_VOLATILE("getShortVolatile"),
 311         PUT_SHORT_VOLATILE("putShortVolatile"),
 312         GET_LONG("getLong"),
 313         PUT_LONG("putLong"),
 314         GET_LONG_VOLATILE("getLongVolatile"),
 315         PUT_LONG_VOLATILE("putLongVolatile"),
 316         GET_FLOAT("getFloat"),
 317         PUT_FLOAT("putFloat"),
 318         GET_FLOAT_VOLATILE("getFloatVolatile"),
 319         PUT_FLOAT_VOLATILE("putFloatVolatile"),
 320         GET_DOUBLE("getDouble"),
 321         PUT_DOUBLE("putDouble"),
 322         GET_DOUBLE_VOLATILE("getDoubleVolatile"),
 323         PUT_DOUBLE_VOLATILE("putDoubleVolatile"),
 324         TRY_FINALLY("tryFinally"),
 325         COLLECT("collect"),
 326         CONVERT("convert"),
 327         SPREAD("spread"),
 328         LOOP("loop"),
 329         FIELD("field"),
 330         GUARD("guard"),
 331         GUARD_WITH_CATCH("guardWithCatch"),
 332         VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
 333         VARHANDLE_INVOKER("VH.invoker", "invoker"),
 334         VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
 335 
 336         final String defaultLambdaName;
 337         final String methodName;
 338 
 339         private Kind(String defaultLambdaName) {
 340             this(defaultLambdaName, defaultLambdaName);
 341         }
 342 
 343         private Kind(String defaultLambdaName, String methodName) {
 344             this.defaultLambdaName = defaultLambdaName;
 345             this.methodName = methodName;
 346         }
 347     }
 348 
 349     LambdaForm(int arity, Name[] names, int result) {
 350         this(arity, names, result, /*forceInline=*/true, /*customized=*/null, Kind.GENERIC);
 351     }
 352     LambdaForm(int arity, Name[] names, int result, Kind kind) {
 353         this(arity, names, result, /*forceInline=*/true, /*customized=*/null, kind);
 354     }
 355     LambdaForm(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized) {
 356         this(arity, names, result, forceInline, customized, Kind.GENERIC);
 357     }
 358     LambdaForm(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
 359         assert(namesOK(arity, names));
 360         this.arity = arity;
 361         this.result = fixResult(result, names);
 362         this.names = names.clone();
 363         this.forceInline = forceInline;
 364         this.customized = customized;
 365         this.kind = kind;
 366         int maxOutArity = normalize();
 367         if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
 368             // Cannot use LF interpreter on very high arity expressions.
 369             assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
 370             compileToBytecode();
 371         }
 372     }
 373     LambdaForm(int arity, Name[] names) {
 374         this(arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null, Kind.GENERIC);
 375     }
 376     LambdaForm(int arity, Name[] names, Kind kind) {
 377         this(arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null, kind);
 378     }
 379     LambdaForm(int arity, Name[] names, boolean forceInline) {
 380         this(arity, names, LAST_RESULT, forceInline, /*customized=*/null, Kind.GENERIC);
 381     }
 382     LambdaForm(int arity, Name[] names, boolean forceInline, Kind kind) {
 383         this(arity, names, LAST_RESULT, forceInline, /*customized=*/null, kind);
 384     }
 385     LambdaForm(Name[] formals, Name[] temps, Name result) {
 386         this(formals.length, buildNames(formals, temps, result), LAST_RESULT, /*forceInline=*/true, /*customized=*/null);
 387     }
 388     LambdaForm(Name[] formals, Name[] temps, Name result, boolean forceInline) {
 389         this(formals.length, buildNames(formals, temps, result), LAST_RESULT, forceInline, /*customized=*/null);
 390     }
 391 
 392     private static Name[] buildNames(Name[] formals, Name[] temps, Name result) {
 393         int arity = formals.length;
 394         int length = arity + temps.length + (result == null ? 0 : 1);
 395         Name[] names = Arrays.copyOf(formals, length);
 396         System.arraycopy(temps, 0, names, arity, temps.length);
 397         if (result != null)
 398             names[length - 1] = result;
 399         return names;
 400     }
 401 
 402     private LambdaForm(MethodType mt) {
 403         // Make a blank lambda form, which returns a constant zero or null.
 404         // It is used as a template for managing the invocation of similar forms that are non-empty.
 405         // Called only from getPreparedForm.
 406         this.arity = mt.parameterCount();
 407         this.result = (mt.returnType() == void.class || mt.returnType() == Void.class) ? -1 : arity;
 408         this.names = buildEmptyNames(arity, mt, result == -1);
 409         this.forceInline = true;
 410         this.customized = null;
 411         this.kind = Kind.ZERO;
 412         assert(nameRefsAreLegal());
 413         assert(isEmpty());
 414         String sig = null;
 415         assert(isValidSignature(sig = basicTypeSignature()));
 416         assert(sig.equals(basicTypeSignature())) : sig + " != " + basicTypeSignature();
 417     }
 418 
 419     private static Name[] buildEmptyNames(int arity, MethodType mt, boolean isVoid) {
 420         Name[] names = arguments(isVoid ? 0 : 1, mt);
 421         if (!isVoid) {
 422             Name zero = new Name(constantZero(basicType(mt.returnType())));
 423             names[arity] = zero.newIndex(arity);
 424         }
 425         return names;
 426     }
 427 
 428     private static int fixResult(int result, Name[] names) {
 429         if (result == LAST_RESULT)
 430             result = names.length - 1;  // might still be void
 431         if (result >= 0 && names[result].type == V_TYPE)
 432             result = VOID_RESULT;
 433         return result;
 434     }
 435 
 436     static boolean debugNames() {
 437         return DEBUG_NAME_COUNTERS != null;
 438     }
 439 
 440     static void associateWithDebugName(LambdaForm form, String name) {
 441         assert (debugNames());
 442         synchronized (DEBUG_NAMES) {
 443             DEBUG_NAMES.put(form, name);
 444         }
 445     }
 446 
 447     String lambdaName() {
 448         if (DEBUG_NAMES != null) {
 449             synchronized (DEBUG_NAMES) {
 450                 String name = DEBUG_NAMES.get(this);
 451                 if (name == null) {
 452                     name = generateDebugName();
 453                 }
 454                 return name;
 455             }
 456         }
 457         return kind.defaultLambdaName;
 458     }
 459 
 460     private String generateDebugName() {
 461         assert (debugNames());
 462         String debugNameStem = kind.defaultLambdaName;
 463         Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
 464         DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
 465         StringBuilder buf = new StringBuilder(debugNameStem);
 466         int leadingZero = buf.length();
 467         buf.append((int) ctr);
 468         for (int i = buf.length() - leadingZero; i < 3; i++) {
 469             buf.insert(leadingZero, '0');
 470         }
 471         buf.append('_');
 472         buf.append(basicTypeSignature());
 473         String name = buf.toString();
 474         associateWithDebugName(this, name);
 475         return name;
 476     }
 477 
 478     private static boolean namesOK(int arity, Name[] names) {
 479         for (int i = 0; i < names.length; i++) {
 480             Name n = names[i];
 481             assert(n != null) : "n is null";
 482             if (i < arity)
 483                 assert( n.isParam()) : n + " is not param at " + i;
 484             else
 485                 assert(!n.isParam()) : n + " is param at " + i;
 486         }
 487         return true;
 488     }
 489 
 490     /** Customize LambdaForm for a particular MethodHandle */
 491     LambdaForm customize(MethodHandle mh) {
 492         LambdaForm customForm = new LambdaForm(arity, names, result, forceInline, mh, kind);
 493         if (COMPILE_THRESHOLD >= 0 && isCompiled) {
 494             // If shared LambdaForm has been compiled, compile customized version as well.
 495             customForm.compileToBytecode();
 496         }
 497         customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
 498         return customForm;
 499     }
 500 
 501     /** Get uncustomized flavor of the LambdaForm */
 502     LambdaForm uncustomize() {
 503         if (customized == null) {
 504             return this;
 505         }
 506         assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
 507         LambdaForm uncustomizedForm = (LambdaForm)transformCache;
 508         if (COMPILE_THRESHOLD >= 0 && isCompiled) {
 509             // If customized LambdaForm has been compiled, compile uncustomized version as well.
 510             uncustomizedForm.compileToBytecode();
 511         }
 512         return uncustomizedForm;
 513     }
 514 
 515     /** Renumber and/or replace params so that they are interned and canonically numbered.
 516      *  @return maximum argument list length among the names (since we have to pass over them anyway)
 517      */
 518     private int normalize() {
 519         Name[] oldNames = null;
 520         int maxOutArity = 0;
 521         int changesStart = 0;
 522         for (int i = 0; i < names.length; i++) {
 523             Name n = names[i];
 524             if (!n.initIndex(i)) {
 525                 if (oldNames == null) {
 526                     oldNames = names.clone();
 527                     changesStart = i;
 528                 }
 529                 names[i] = n.cloneWithIndex(i);
 530             }
 531             if (n.arguments != null && maxOutArity < n.arguments.length)
 532                 maxOutArity = n.arguments.length;
 533         }
 534         if (oldNames != null) {
 535             int startFixing = arity;
 536             if (startFixing <= changesStart)
 537                 startFixing = changesStart+1;
 538             for (int i = startFixing; i < names.length; i++) {
 539                 Name fixed = names[i].replaceNames(oldNames, names, changesStart, i);
 540                 names[i] = fixed.newIndex(i);
 541             }
 542         }
 543         assert(nameRefsAreLegal());
 544         int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
 545         boolean needIntern = false;
 546         for (int i = 0; i < maxInterned; i++) {
 547             Name n = names[i], n2 = internArgument(n);
 548             if (n != n2) {
 549                 names[i] = n2;
 550                 needIntern = true;
 551             }
 552         }
 553         if (needIntern) {
 554             for (int i = arity; i < names.length; i++) {
 555                 names[i].internArguments();
 556             }
 557         }
 558         assert(nameRefsAreLegal());
 559         return maxOutArity;
 560     }
 561 
 562     /**
 563      * Check that all embedded Name references are localizable to this lambda,
 564      * and are properly ordered after their corresponding definitions.
 565      * <p>
 566      * Note that a Name can be local to multiple lambdas, as long as
 567      * it possesses the same index in each use site.
 568      * This allows Name references to be freely reused to construct
 569      * fresh lambdas, without confusion.
 570      */
 571     boolean nameRefsAreLegal() {
 572         assert(arity >= 0 && arity <= names.length);
 573         assert(result >= -1 && result < names.length);
 574         // Do all names possess an index consistent with their local definition order?
 575         for (int i = 0; i < arity; i++) {
 576             Name n = names[i];
 577             assert(n.index() == i) : Arrays.asList(n.index(), i);
 578             assert(n.isParam());
 579         }
 580         // Also, do all local name references
 581         for (int i = arity; i < names.length; i++) {
 582             Name n = names[i];
 583             assert(n.index() == i);
 584             for (Object arg : n.arguments) {
 585                 if (arg instanceof Name) {
 586                     Name n2 = (Name) arg;
 587                     int i2 = n2.index;
 588                     assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
 589                     assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
 590                     assert(i2 < i);  // ref must come after def!
 591                 }
 592             }
 593         }
 594         return true;
 595     }
 596 
 597     /** Invoke this form on the given arguments. */
 598     // final Object invoke(Object... args) throws Throwable {
 599     //     // NYI: fit this into the fast path?
 600     //     return interpretWithArguments(args);
 601     // }
 602 
 603     /** Report the return type. */
 604     BasicType returnType() {
 605         if (result < 0)  return V_TYPE;
 606         Name n = names[result];
 607         return n.type;
 608     }
 609 
 610     /** Report the N-th argument type. */
 611     BasicType parameterType(int n) {
 612         return parameter(n).type;
 613     }
 614 
 615     /** Report the N-th argument name. */
 616     Name parameter(int n) {
 617         assert(n < arity);
 618         Name param = names[n];
 619         assert(param.isParam());
 620         return param;
 621     }
 622 
 623     /** Report the N-th argument type constraint. */
 624     Object parameterConstraint(int n) {
 625         return parameter(n).constraint;
 626     }
 627 
 628     /** Report the arity. */
 629     int arity() {
 630         return arity;
 631     }
 632 
 633     /** Report the number of expressions (non-parameter names). */
 634     int expressionCount() {
 635         return names.length - arity;
 636     }
 637 
 638     /** Return the method type corresponding to my basic type signature. */
 639     MethodType methodType() {
 640         Class<?>[] ptypes = new Class<?>[arity];
 641         for (int i = 0; i < arity; ++i) {
 642             ptypes[i] = parameterType(i).btClass;
 643         }
 644         return MethodType.makeImpl(returnType().btClass, ptypes, true);
 645     }
 646 
 647     /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
 648     final String basicTypeSignature() {
 649         StringBuilder buf = new StringBuilder(arity() + 3);
 650         for (int i = 0, a = arity(); i < a; i++)
 651             buf.append(parameterType(i).basicTypeChar());
 652         return buf.append('_').append(returnType().basicTypeChar()).toString();
 653     }
 654     static int signatureArity(String sig) {
 655         assert(isValidSignature(sig));
 656         return sig.indexOf('_');
 657     }
 658     static BasicType signatureReturn(String sig) {
 659         return basicType(sig.charAt(signatureArity(sig) + 1));
 660     }
 661     static boolean isValidSignature(String sig) {
 662         int arity = sig.indexOf('_');
 663         if (arity < 0)  return false;  // must be of the form *_*
 664         int siglen = sig.length();
 665         if (siglen != arity + 2)  return false;  // *_X
 666         for (int i = 0; i < siglen; i++) {
 667             if (i == arity)  continue;  // skip '_'
 668             char c = sig.charAt(i);
 669             if (c == 'V')
 670                 return (i == siglen - 1 && arity == siglen - 2);
 671             if (!isArgBasicTypeChar(c))  return false; // must be [LIJFD]
 672         }
 673         return true;  // [LIJFD]*_[LIJFDV]
 674     }
 675     static MethodType signatureType(String sig) {
 676         Class<?>[] ptypes = new Class<?>[signatureArity(sig)];
 677         for (int i = 0; i < ptypes.length; i++)
 678             ptypes[i] = basicType(sig.charAt(i)).btClass;
 679         Class<?> rtype = signatureReturn(sig).btClass;
 680         return MethodType.makeImpl(rtype, ptypes, true);
 681     }
 682 
 683     /**
 684      * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
 685      */
 686     boolean isSelectAlternative(int pos) {
 687         // selectAlternative idiom:
 688         //   t_{n}:L=MethodHandleImpl.selectAlternative(...)
 689         //   t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
 690         if (pos+1 >= names.length)  return false;
 691         Name name0 = names[pos];
 692         Name name1 = names[pos+1];
 693         return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
 694                 name1.isInvokeBasic() &&
 695                 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
 696                 lastUseIndex(name0) == pos+1;     // t_{n} is local: used only in t_{n+1}
 697     }
 698 
 699     private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
 700         if (pos+2 >= names.length)  return false;
 701         Name name0 = names[pos];
 702         Name name1 = names[pos+1];
 703         Name name2 = names[pos+2];
 704         return name1.refersTo(MethodHandleImpl.class, idiomName) &&
 705                 name0.isInvokeBasic() &&
 706                 name2.isInvokeBasic() &&
 707                 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
 708                 lastUseIndex(name0) == pos+1 &&       // t_{n} is local: used only in t_{n+1}
 709                 name2.lastUseIndex(name1) == 1 &&     // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
 710                 lastUseIndex(name1) == pos+2;         // t_{n+1} is local: used only in t_{n+2}
 711     }
 712 
 713     /**
 714      * Check if i-th name is a start of GuardWithCatch idiom.
 715      */
 716     boolean isGuardWithCatch(int pos) {
 717         // GuardWithCatch idiom:
 718         //   t_{n}:L=MethodHandle.invokeBasic(...)
 719         //   t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
 720         //   t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
 721         return isMatchingIdiom(pos, "guardWithCatch", 3);
 722     }
 723 
 724     /**
 725      * Check if i-th name is a start of the tryFinally idiom.
 726      */
 727     boolean isTryFinally(int pos) {
 728         // tryFinally idiom:
 729         //   t_{n}:L=MethodHandle.invokeBasic(...)
 730         //   t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
 731         //   t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
 732         return isMatchingIdiom(pos, "tryFinally", 2);
 733     }
 734 
 735     /**
 736      * Check if i-th name is a start of the loop idiom.
 737      */
 738     boolean isLoop(int pos) {
 739         // loop idiom:
 740         //   t_{n}:L=MethodHandle.invokeBasic(...)
 741         //   t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
 742         //   t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
 743         return isMatchingIdiom(pos, "loop", 2);
 744     }
 745 
 746     /*
 747      * Code generation issues:
 748      *
 749      * Compiled LFs should be reusable in general.
 750      * The biggest issue is how to decide when to pull a name into
 751      * the bytecode, versus loading a reified form from the MH data.
 752      *
 753      * For example, an asType wrapper may require execution of a cast
 754      * after a call to a MH.  The target type of the cast can be placed
 755      * as a constant in the LF itself.  This will force the cast type
 756      * to be compiled into the bytecodes and native code for the MH.
 757      * Or, the target type of the cast can be erased in the LF, and
 758      * loaded from the MH data.  (Later on, if the MH as a whole is
 759      * inlined, the data will flow into the inlined instance of the LF,
 760      * as a constant, and the end result will be an optimal cast.)
 761      *
 762      * This erasure of cast types can be done with any use of
 763      * reference types.  It can also be done with whole method
 764      * handles.  Erasing a method handle might leave behind
 765      * LF code that executes correctly for any MH of a given
 766      * type, and load the required MH from the enclosing MH's data.
 767      * Or, the erasure might even erase the expected MT.
 768      *
 769      * Also, for direct MHs, the MemberName of the target
 770      * could be erased, and loaded from the containing direct MH.
 771      * As a simple case, a LF for all int-valued non-static
 772      * field getters would perform a cast on its input argument
 773      * (to non-constant base type derived from the MemberName)
 774      * and load an integer value from the input object
 775      * (at a non-constant offset also derived from the MemberName).
 776      * Such MN-erased LFs would be inlinable back to optimized
 777      * code, whenever a constant enclosing DMH is available
 778      * to supply a constant MN from its data.
 779      *
 780      * The main problem here is to keep LFs reasonably generic,
 781      * while ensuring that hot spots will inline good instances.
 782      * "Reasonably generic" means that we don't end up with
 783      * repeated versions of bytecode or machine code that do
 784      * not differ in their optimized form.  Repeated versions
 785      * of machine would have the undesirable overheads of
 786      * (a) redundant compilation work and (b) extra I$ pressure.
 787      * To control repeated versions, we need to be ready to
 788      * erase details from LFs and move them into MH data,
 789      * whevener those details are not relevant to significant
 790      * optimization.  "Significant" means optimization of
 791      * code that is actually hot.
 792      *
 793      * Achieving this may require dynamic splitting of MHs, by replacing
 794      * a generic LF with a more specialized one, on the same MH,
 795      * if (a) the MH is frequently executed and (b) the MH cannot
 796      * be inlined into a containing caller, such as an invokedynamic.
 797      *
 798      * Compiled LFs that are no longer used should be GC-able.
 799      * If they contain non-BCP references, they should be properly
 800      * interlinked with the class loader(s) that their embedded types
 801      * depend on.  This probably means that reusable compiled LFs
 802      * will be tabulated (indexed) on relevant class loaders,
 803      * or else that the tables that cache them will have weak links.
 804      */
 805 
 806     /**
 807      * Make this LF directly executable, as part of a MethodHandle.
 808      * Invariant:  Every MH which is invoked must prepare its LF
 809      * before invocation.
 810      * (In principle, the JVM could do this very lazily,
 811      * as a sort of pre-invocation linkage step.)
 812      */
 813     public void prepare() {
 814         if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
 815             compileToBytecode();
 816         }
 817         if (this.vmentry != null) {
 818             // already prepared (e.g., a primitive DMH invoker form)
 819             return;
 820         }
 821         MethodType mtype = methodType();
 822         LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
 823         if (prep == null) {
 824             assert (isValidSignature(basicTypeSignature()));
 825             prep = new LambdaForm(mtype);
 826             prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
 827             prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
 828         }
 829         this.vmentry = prep.vmentry;
 830         // TO DO: Maybe add invokeGeneric, invokeWithArguments
 831     }
 832 
 833     private static @Stable PerfCounter LF_FAILED;
 834 
 835     private static PerfCounter failedCompilationCounter() {
 836         if (LF_FAILED == null) {
 837             LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
 838         }
 839         return LF_FAILED;
 840     }
 841 
 842     /** Generate optimizable bytecode for this form. */
 843     void compileToBytecode() {
 844         if (forceInterpretation()) {
 845             return; // this should not be compiled
 846         }
 847         if (vmentry != null && isCompiled) {
 848             return;  // already compiled somehow
 849         }
 850 
 851         // Obtain the invoker MethodType outside of the following try block.
 852         // This ensures that an IllegalArgumentException is directly thrown if the
 853         // type would have 256 or more parameters
 854         MethodType invokerType = methodType();
 855         assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
 856         try {
 857             vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
 858             if (TRACE_INTERPRETER)
 859                 traceInterpreter("compileToBytecode", this);
 860             isCompiled = true;
 861         } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
 862             // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
 863             invocationCounter = -1;
 864             failedCompilationCounter().increment();
 865             if (LOG_LF_COMPILATION_FAILURE) {
 866                 System.out.println("LambdaForm compilation failed: " + this);
 867                 bge.printStackTrace(System.out);
 868             }
 869         } catch (Error e) {
 870             // Pass through any error
 871             throw e;
 872         } catch (Exception e) {
 873             // Wrap any exception
 874             throw newInternalError(this.toString(), e);
 875         }
 876     }
 877 
 878     // The next few routines are called only from assert expressions
 879     // They verify that the built-in invokers process the correct raw data types.
 880     private static boolean argumentTypesMatch(String sig, Object[] av) {
 881         int arity = signatureArity(sig);
 882         assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
 883         assert(av[0] instanceof MethodHandle) : "av[0] not instace of MethodHandle: " + av[0];
 884         MethodHandle mh = (MethodHandle) av[0];
 885         MethodType mt = mh.type();
 886         assert(mt.parameterCount() == arity-1);
 887         for (int i = 0; i < av.length; i++) {
 888             Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
 889             assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
 890         }
 891         return true;
 892     }
 893     private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
 894         // The following line is needed because (...)void method handles can use non-void invokers
 895         if (type == void.class)  tc = V_TYPE;   // can drop any kind of value
 896         assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
 897         switch (tc) {
 898         case I_TYPE: assert checkInt(type, x)   : "checkInt(" + type + "," + x +")";   break;
 899         case J_TYPE: assert x instanceof Long   : "instanceof Long: " + x;             break;
 900         case F_TYPE: assert x instanceof Float  : "instanceof Float: " + x;            break;
 901         case D_TYPE: assert x instanceof Double : "instanceof Double: " + x;           break;
 902         case L_TYPE: assert checkRef(type, x)   : "checkRef(" + type + "," + x + ")";  break;
 903         case V_TYPE: break;  // allow anything here; will be dropped
 904         default:  assert(false);
 905         }
 906         return true;
 907     }
 908     private static boolean checkInt(Class<?> type, Object x) {
 909         assert(x instanceof Integer);
 910         if (type == int.class)  return true;
 911         Wrapper w = Wrapper.forBasicType(type);
 912         assert(w.isSubwordOrInt());
 913         Object x1 = Wrapper.INT.wrap(w.wrap(x));
 914         return x.equals(x1);
 915     }
 916     private static boolean checkRef(Class<?> type, Object x) {
 917         assert(!type.isPrimitive());
 918         if (x == null)  return true;
 919         if (type.isInterface())  return true;
 920         return type.isInstance(x);
 921     }
 922 
 923     /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
 924     private static final int COMPILE_THRESHOLD;
 925     static {
 926         COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
 927     }
 928     private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
 929 
 930     private boolean forceInterpretation() {
 931         return invocationCounter == -1;
 932     }
 933 
 934     @Hidden
 935     @DontInline
 936     /** Interpretively invoke this form on the given arguments. */
 937     Object interpretWithArguments(Object... argumentValues) throws Throwable {
 938         if (TRACE_INTERPRETER)
 939             return interpretWithArgumentsTracing(argumentValues);
 940         checkInvocationCounter();
 941         assert(arityCheck(argumentValues));
 942         Object[] values = Arrays.copyOf(argumentValues, names.length);
 943         for (int i = argumentValues.length; i < values.length; i++) {
 944             values[i] = interpretName(names[i], values);
 945         }
 946         Object rv = (result < 0) ? null : values[result];
 947         assert(resultCheck(argumentValues, rv));
 948         return rv;
 949     }
 950 
 951     @Hidden
 952     @DontInline
 953     /** Evaluate a single Name within this form, applying its function to its arguments. */
 954     Object interpretName(Name name, Object[] values) throws Throwable {
 955         if (TRACE_INTERPRETER)
 956             traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
 957         Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
 958         for (int i = 0; i < arguments.length; i++) {
 959             Object a = arguments[i];
 960             if (a instanceof Name) {
 961                 int i2 = ((Name)a).index();
 962                 assert(names[i2] == a);
 963                 a = values[i2];
 964                 arguments[i] = a;
 965             }
 966         }
 967         return name.function.invokeWithArguments(arguments);
 968     }
 969 
 970     private void checkInvocationCounter() {
 971         if (COMPILE_THRESHOLD != 0 &&
 972             !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
 973             invocationCounter++;  // benign race
 974             if (invocationCounter >= COMPILE_THRESHOLD) {
 975                 // Replace vmentry with a bytecode version of this LF.
 976                 compileToBytecode();
 977             }
 978         }
 979     }
 980     Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
 981         traceInterpreter("[ interpretWithArguments", this, argumentValues);
 982         if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
 983             int ctr = invocationCounter++;  // benign race
 984             traceInterpreter("| invocationCounter", ctr);
 985             if (invocationCounter >= COMPILE_THRESHOLD) {
 986                 compileToBytecode();
 987             }
 988         }
 989         Object rval;
 990         try {
 991             assert(arityCheck(argumentValues));
 992             Object[] values = Arrays.copyOf(argumentValues, names.length);
 993             for (int i = argumentValues.length; i < values.length; i++) {
 994                 values[i] = interpretName(names[i], values);
 995             }
 996             rval = (result < 0) ? null : values[result];
 997         } catch (Throwable ex) {
 998             traceInterpreter("] throw =>", ex);
 999             throw ex;
1000         }
1001         traceInterpreter("] return =>", rval);
1002         return rval;
1003     }
1004 
1005     static void traceInterpreter(String event, Object obj, Object... args) {
1006         if (TRACE_INTERPRETER) {
1007             System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
1008         }
1009     }
1010     static void traceInterpreter(String event, Object obj) {
1011         traceInterpreter(event, obj, (Object[])null);
1012     }
1013     private boolean arityCheck(Object[] argumentValues) {
1014         assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
1015         // also check that the leading (receiver) argument is somehow bound to this LF:
1016         assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
1017         MethodHandle mh = (MethodHandle) argumentValues[0];
1018         assert(mh.internalForm() == this);
1019         // note:  argument #0 could also be an interface wrapper, in the future
1020         argumentTypesMatch(basicTypeSignature(), argumentValues);
1021         return true;
1022     }
1023     private boolean resultCheck(Object[] argumentValues, Object result) {
1024         MethodHandle mh = (MethodHandle) argumentValues[0];
1025         MethodType mt = mh.type();
1026         assert(valueMatches(returnType(), mt.returnType(), result));
1027         return true;
1028     }
1029 
1030     private boolean isEmpty() {
1031         if (result < 0)
1032             return (names.length == arity);
1033         else if (result == arity && names.length == arity + 1)
1034             return names[arity].isConstantZero();
1035         else
1036             return false;
1037     }
1038 
1039     public String toString() {
1040         String lambdaName = lambdaName();
1041         StringBuilder buf = new StringBuilder(lambdaName + "=Lambda(");
1042         for (int i = 0; i < names.length; i++) {
1043             if (i == arity)  buf.append(")=>{");
1044             Name n = names[i];
1045             if (i >= arity)  buf.append("\n    ");
1046             buf.append(n.paramString());
1047             if (i < arity) {
1048                 if (i+1 < arity)  buf.append(",");
1049                 continue;
1050             }
1051             buf.append("=").append(n.exprString());
1052             buf.append(";");
1053         }
1054         if (arity == names.length)  buf.append(")=>{");
1055         buf.append(result < 0 ? "void" : names[result]).append("}");
1056         if (TRACE_INTERPRETER) {
1057             // Extra verbosity:
1058             buf.append(":").append(basicTypeSignature());
1059             buf.append("/").append(vmentry);
1060         }
1061         return buf.toString();
1062     }
1063 
1064     @Override
1065     public boolean equals(Object obj) {
1066         return obj instanceof LambdaForm && equals((LambdaForm)obj);
1067     }
1068     public boolean equals(LambdaForm that) {
1069         if (this.result != that.result)  return false;
1070         return Arrays.equals(this.names, that.names);
1071     }
1072     public int hashCode() {
1073         return result + 31 * Arrays.hashCode(names);
1074     }
1075     LambdaFormEditor editor() {
1076         return LambdaFormEditor.lambdaFormEditor(this);
1077     }
1078 
1079     boolean contains(Name name) {
1080         int pos = name.index();
1081         if (pos >= 0) {
1082             return pos < names.length && name.equals(names[pos]);
1083         }
1084         for (int i = arity; i < names.length; i++) {
1085             if (name.equals(names[i]))
1086                 return true;
1087         }
1088         return false;
1089     }
1090 
1091     static class NamedFunction {
1092         final MemberName member;
1093         private @Stable MethodHandle resolvedHandle;
1094         @Stable MethodHandle invoker;
1095         private final MethodHandleImpl.Intrinsic intrinsicName;
1096 
1097         NamedFunction(MethodHandle resolvedHandle) {
1098             this(resolvedHandle.internalMemberName(), resolvedHandle, MethodHandleImpl.Intrinsic.NONE);
1099         }
1100         NamedFunction(MethodHandle resolvedHandle, MethodHandleImpl.Intrinsic intrinsic) {
1101             this(resolvedHandle.internalMemberName(), resolvedHandle, intrinsic);
1102         }
1103         NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1104             this(member, resolvedHandle, MethodHandleImpl.Intrinsic.NONE);
1105         }
1106         NamedFunction(MemberName member, MethodHandle resolvedHandle, MethodHandleImpl.Intrinsic intrinsic) {
1107             this.member = member;
1108             this.resolvedHandle = resolvedHandle;
1109             this.intrinsicName = intrinsic;
1110             assert(resolvedHandle == null ||
1111                    resolvedHandle.intrinsicName() == MethodHandleImpl.Intrinsic.NONE ||
1112                    resolvedHandle.intrinsicName() == intrinsic) : resolvedHandle.intrinsicName() + " != " + intrinsic;
1113              // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1114              //assert(!isInvokeBasic(member));
1115         }
1116         NamedFunction(MethodType basicInvokerType) {
1117             assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1118             if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1119                 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1120                 this.member = resolvedHandle.internalMemberName();
1121             } else {
1122                 // necessary to pass BigArityTest
1123                 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1124             }
1125             this.intrinsicName = MethodHandleImpl.Intrinsic.NONE;
1126             assert(isInvokeBasic(member));
1127         }
1128 
1129         private static boolean isInvokeBasic(MemberName member) {
1130             return member != null &&
1131                    member.getDeclaringClass() == MethodHandle.class &&
1132                   "invokeBasic".equals(member.getName());
1133         }
1134 
1135         // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1136         // Any LambdaForm containing such a member is not interpretable.
1137         // This is OK, since all such LFs are prepared with special primitive vmentry points.
1138         // And even without the resolvedHandle, the name can still be compiled and optimized.
1139         NamedFunction(Method method) {
1140             this(new MemberName(method));
1141         }
1142         NamedFunction(MemberName member) {
1143             this(member, null);
1144         }
1145 
1146         MethodHandle resolvedHandle() {
1147             if (resolvedHandle == null)  resolve();
1148             return resolvedHandle;
1149         }
1150 
1151         synchronized void resolve() {
1152             if (resolvedHandle == null) {
1153                 resolvedHandle = DirectMethodHandle.make(member);
1154             }
1155         }
1156 
1157         @Override
1158         public boolean equals(Object other) {
1159             if (this == other) return true;
1160             if (other == null) return false;
1161             if (!(other instanceof NamedFunction)) return false;
1162             NamedFunction that = (NamedFunction) other;
1163             return this.member != null && this.member.equals(that.member);
1164         }
1165 
1166         @Override
1167         public int hashCode() {
1168             if (member != null)
1169                 return member.hashCode();
1170             return super.hashCode();
1171         }
1172 
1173         static final MethodType INVOKER_METHOD_TYPE =
1174             MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1175 
1176         private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1177             typeForm = typeForm.basicType().form();  // normalize to basic type
1178             MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1179             if (mh != null)  return mh;
1180             MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm);  // this could take a while
1181             mh = DirectMethodHandle.make(invoker);
1182             MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1183             if (mh2 != null)  return mh2;  // benign race
1184             if (!mh.type().equals(INVOKER_METHOD_TYPE))
1185                 throw newInternalError(mh.debugString());
1186             return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1187         }
1188 
1189         @Hidden
1190         Object invokeWithArguments(Object... arguments) throws Throwable {
1191             // If we have a cached invoker, call it right away.
1192             // NOTE: The invoker always returns a reference value.
1193             if (TRACE_INTERPRETER)  return invokeWithArgumentsTracing(arguments);
1194             return invoker().invokeBasic(resolvedHandle(), arguments);
1195         }
1196 
1197         @Hidden
1198         Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1199             Object rval;
1200             try {
1201                 traceInterpreter("[ call", this, arguments);
1202                 if (invoker == null) {
1203                     traceInterpreter("| getInvoker", this);
1204                     invoker();
1205                 }
1206                 // resolvedHandle might be uninitialized, ok for tracing
1207                 if (resolvedHandle == null) {
1208                     traceInterpreter("| resolve", this);
1209                     resolvedHandle();
1210                 }
1211                 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1212             } catch (Throwable ex) {
1213                 traceInterpreter("] throw =>", ex);
1214                 throw ex;
1215             }
1216             traceInterpreter("] return =>", rval);
1217             return rval;
1218         }
1219 
1220         private MethodHandle invoker() {
1221             if (invoker != null)  return invoker;
1222             // Get an invoker and cache it.
1223             return invoker = computeInvoker(methodType().form());
1224         }
1225 
1226         MethodType methodType() {
1227             if (resolvedHandle != null)
1228                 return resolvedHandle.type();
1229             else
1230                 // only for certain internal LFs during bootstrapping
1231                 return member.getInvocationType();
1232         }
1233 
1234         MemberName member() {
1235             assert(assertMemberIsConsistent());
1236             return member;
1237         }
1238 
1239         // Called only from assert.
1240         private boolean assertMemberIsConsistent() {
1241             if (resolvedHandle instanceof DirectMethodHandle) {
1242                 MemberName m = resolvedHandle.internalMemberName();
1243                 assert(m.equals(member));
1244             }
1245             return true;
1246         }
1247 
1248         Class<?> memberDeclaringClassOrNull() {
1249             return (member == null) ? null : member.getDeclaringClass();
1250         }
1251 
1252         BasicType returnType() {
1253             return basicType(methodType().returnType());
1254         }
1255 
1256         BasicType parameterType(int n) {
1257             return basicType(methodType().parameterType(n));
1258         }
1259 
1260         int arity() {
1261             return methodType().parameterCount();
1262         }
1263 
1264         public String toString() {
1265             if (member == null)  return String.valueOf(resolvedHandle);
1266             return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1267         }
1268 
1269         public boolean isIdentity() {
1270             return this.equals(identity(returnType()));
1271         }
1272 
1273         public boolean isConstantZero() {
1274             return this.equals(constantZero(returnType()));
1275         }
1276 
1277         public MethodHandleImpl.Intrinsic intrinsicName() {
1278             return intrinsicName;

1279         }
1280     }
1281 
1282     public static String basicTypeSignature(MethodType type) {
1283         int params = type.parameterCount();
1284         char[] sig = new char[params + 2];
1285         int sigp = 0;
1286         while (sigp < params) {
1287             sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1288         }
1289         sig[sigp++] = '_';
1290         sig[sigp++] = basicTypeChar(type.returnType());
1291         assert(sigp == sig.length);
1292         return String.valueOf(sig);
1293     }
1294     public static String shortenSignature(String signature) {
1295         // Hack to make signatures more readable when they show up in method names.
1296         final int NO_CHAR = -1, MIN_RUN = 3;
1297         int c0, c1 = NO_CHAR, c1reps = 0;
1298         StringBuilder buf = null;
1299         int len = signature.length();
1300         if (len < MIN_RUN)  return signature;
1301         for (int i = 0; i <= len; i++) {
1302             // shift in the next char:
1303             c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1304             if (c1 == c0) { ++c1reps; continue; }
1305             // shift in the next count:
1306             int c0reps = c1reps; c1reps = 1;
1307             // end of a  character run
1308             if (c0reps < MIN_RUN) {
1309                 if (buf != null) {
1310                     while (--c0reps >= 0)
1311                         buf.append((char)c0);
1312                 }
1313                 continue;
1314             }
1315             // found three or more in a row
1316             if (buf == null)
1317                 buf = new StringBuilder().append(signature, 0, i - c0reps);
1318             buf.append((char)c0).append(c0reps);
1319         }
1320         return (buf == null) ? signature : buf.toString();
1321     }
1322 
1323     static final class Name {
1324         final BasicType type;
1325         @Stable short index;
1326         final NamedFunction function;
1327         final Object constraint;  // additional type information, if not null
1328         @Stable final Object[] arguments;
1329 
1330         private Name(int index, BasicType type, NamedFunction function, Object[] arguments) {
1331             this.index = (short)index;
1332             this.type = type;
1333             this.function = function;
1334             this.arguments = arguments;
1335             this.constraint = null;
1336             assert(this.index == index);
1337         }
1338         private Name(Name that, Object constraint) {
1339             this.index = that.index;
1340             this.type = that.type;
1341             this.function = that.function;
1342             this.arguments = that.arguments;
1343             this.constraint = constraint;
1344             assert(constraint == null || isParam());  // only params have constraints
1345             assert(constraint == null || constraint instanceof BoundMethodHandle.SpeciesData || constraint instanceof Class);
1346         }
1347         Name(MethodHandle function, Object... arguments) {
1348             this(new NamedFunction(function), arguments);
1349         }
1350         Name(MethodType functionType, Object... arguments) {
1351             this(new NamedFunction(functionType), arguments);
1352             assert(arguments[0] instanceof Name && ((Name)arguments[0]).type == L_TYPE);
1353         }
1354         Name(MemberName function, Object... arguments) {
1355             this(new NamedFunction(function), arguments);
1356         }
1357         Name(NamedFunction function, Object... arguments) {
1358             this(-1, function.returnType(), function, arguments = Arrays.copyOf(arguments, arguments.length, Object[].class));
1359             assert(typesMatch(function, arguments));
1360         }
1361         /** Create a raw parameter of the given type, with an expected index. */
1362         Name(int index, BasicType type) {
1363             this(index, type, null, null);
1364         }
1365         /** Create a raw parameter of the given type. */
1366         Name(BasicType type) { this(-1, type); }
1367 
1368         BasicType type() { return type; }
1369         int index() { return index; }
1370         boolean initIndex(int i) {
1371             if (index != i) {
1372                 if (index != -1)  return false;
1373                 index = (short)i;
1374             }
1375             return true;
1376         }
1377         char typeChar() {
1378             return type.btChar;
1379         }
1380 
1381         void resolve() {
1382             if (function != null)
1383                 function.resolve();
1384         }
1385 
1386         Name newIndex(int i) {
1387             if (initIndex(i))  return this;
1388             return cloneWithIndex(i);
1389         }
1390         Name cloneWithIndex(int i) {
1391             Object[] newArguments = (arguments == null) ? null : arguments.clone();
1392             return new Name(i, type, function, newArguments).withConstraint(constraint);
1393         }
1394         Name withConstraint(Object constraint) {
1395             if (constraint == this.constraint)  return this;
1396             return new Name(this, constraint);
1397         }
1398         Name replaceName(Name oldName, Name newName) {  // FIXME: use replaceNames uniformly
1399             if (oldName == newName)  return this;
1400             @SuppressWarnings("LocalVariableHidesMemberVariable")
1401             Object[] arguments = this.arguments;
1402             if (arguments == null)  return this;
1403             boolean replaced = false;
1404             for (int j = 0; j < arguments.length; j++) {
1405                 if (arguments[j] == oldName) {
1406                     if (!replaced) {
1407                         replaced = true;
1408                         arguments = arguments.clone();
1409                     }
1410                     arguments[j] = newName;
1411                 }
1412             }
1413             if (!replaced)  return this;
1414             return new Name(function, arguments);
1415         }
1416         /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1417          *  Limit such replacements to {@code start<=i<end}.  Return possibly changed self.
1418          */
1419         Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1420             if (start >= end)  return this;
1421             @SuppressWarnings("LocalVariableHidesMemberVariable")
1422             Object[] arguments = this.arguments;
1423             boolean replaced = false;
1424         eachArg:
1425             for (int j = 0; j < arguments.length; j++) {
1426                 if (arguments[j] instanceof Name) {
1427                     Name n = (Name) arguments[j];
1428                     int check = n.index;
1429                     // harmless check to see if the thing is already in newNames:
1430                     if (check >= 0 && check < newNames.length && n == newNames[check])
1431                         continue eachArg;
1432                     // n might not have the correct index: n != oldNames[n.index].
1433                     for (int i = start; i < end; i++) {
1434                         if (n == oldNames[i]) {
1435                             if (n == newNames[i])
1436                                 continue eachArg;
1437                             if (!replaced) {
1438                                 replaced = true;
1439                                 arguments = arguments.clone();
1440                             }
1441                             arguments[j] = newNames[i];
1442                             continue eachArg;
1443                         }
1444                     }
1445                 }
1446             }
1447             if (!replaced)  return this;
1448             return new Name(function, arguments);
1449         }
1450         void internArguments() {
1451             @SuppressWarnings("LocalVariableHidesMemberVariable")
1452             Object[] arguments = this.arguments;
1453             for (int j = 0; j < arguments.length; j++) {
1454                 if (arguments[j] instanceof Name) {
1455                     Name n = (Name) arguments[j];
1456                     if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1457                         arguments[j] = internArgument(n);
1458                 }
1459             }
1460         }
1461         boolean isParam() {
1462             return function == null;
1463         }
1464         boolean isConstantZero() {
1465             return !isParam() && arguments.length == 0 && function.isConstantZero();
1466         }
1467 
1468         boolean refersTo(Class<?> declaringClass, String methodName) {
1469             return function != null &&
1470                     function.member() != null && function.member().refersTo(declaringClass, methodName);
1471         }
1472 
1473         /**
1474          * Check if MemberName is a call to MethodHandle.invokeBasic.
1475          */
1476         boolean isInvokeBasic() {
1477             if (function == null)
1478                 return false;
1479             if (arguments.length < 1)
1480                 return false;  // must have MH argument
1481             MemberName member = function.member();
1482             return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1483                     !member.isPublic() && !member.isStatic();
1484         }
1485 
1486         /**
1487          * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1488          */
1489         boolean isLinkerMethodInvoke() {
1490             if (function == null)
1491                 return false;
1492             if (arguments.length < 1)
1493                 return false;  // must have MH argument
1494             MemberName member = function.member();
1495             return member != null &&
1496                     member.getDeclaringClass() == MethodHandle.class &&
1497                     !member.isPublic() && member.isStatic() &&
1498                     member.getName().startsWith("linkTo");
1499         }
1500 
1501         public String toString() {
1502             return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1503         }
1504         public String debugString() {
1505             String s = paramString();
1506             return (function == null) ? s : s + "=" + exprString();
1507         }
1508         public String paramString() {
1509             String s = toString();
1510             Object c = constraint;
1511             if (c == null)
1512                 return s;
1513             if (c instanceof Class)  c = ((Class<?>)c).getSimpleName();
1514             return s + "/" + c;
1515         }
1516         public String exprString() {
1517             if (function == null)  return toString();
1518             StringBuilder buf = new StringBuilder(function.toString());
1519             buf.append("(");
1520             String cma = "";
1521             for (Object a : arguments) {
1522                 buf.append(cma); cma = ",";
1523                 if (a instanceof Name || a instanceof Integer)
1524                     buf.append(a);
1525                 else
1526                     buf.append("(").append(a).append(")");
1527             }
1528             buf.append(")");
1529             return buf.toString();
1530         }
1531 
1532         private boolean typesMatch(NamedFunction function, Object ... arguments) {
1533             assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1534             for (int i = 0; i < arguments.length; i++) {
1535                 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1536             }
1537             return true;
1538         }
1539 
1540         private static boolean typesMatch(BasicType parameterType, Object object) {
1541             if (object instanceof Name) {
1542                 return ((Name)object).type == parameterType;
1543             }
1544             switch (parameterType) {
1545                 case I_TYPE:  return object instanceof Integer;
1546                 case J_TYPE:  return object instanceof Long;
1547                 case F_TYPE:  return object instanceof Float;
1548                 case D_TYPE:  return object instanceof Double;
1549             }
1550             assert(parameterType == L_TYPE);
1551             return true;
1552         }
1553 
1554         /** Return the index of the last occurrence of n in the argument array.
1555          *  Return -1 if the name is not used.
1556          */
1557         int lastUseIndex(Name n) {
1558             if (arguments == null)  return -1;
1559             for (int i = arguments.length; --i >= 0; ) {
1560                 if (arguments[i] == n)  return i;
1561             }
1562             return -1;
1563         }
1564 
1565         /** Return the number of occurrences of n in the argument array.
1566          *  Return 0 if the name is not used.
1567          */
1568         int useCount(Name n) {
1569             if (arguments == null)  return 0;
1570             int count = 0;
1571             for (int i = arguments.length; --i >= 0; ) {
1572                 if (arguments[i] == n)  ++count;
1573             }
1574             return count;
1575         }
1576 
1577         boolean contains(Name n) {
1578             return this == n || lastUseIndex(n) >= 0;
1579         }
1580 
1581         public boolean equals(Name that) {
1582             if (this == that)  return true;
1583             if (isParam())
1584                 // each parameter is a unique atom
1585                 return false;  // this != that
1586             return
1587                 //this.index == that.index &&
1588                 this.type == that.type &&
1589                 this.function.equals(that.function) &&
1590                 Arrays.equals(this.arguments, that.arguments);
1591         }
1592         @Override
1593         public boolean equals(Object x) {
1594             return x instanceof Name && equals((Name)x);
1595         }
1596         @Override
1597         public int hashCode() {
1598             if (isParam())
1599                 return index | (type.ordinal() << 8);
1600             return function.hashCode() ^ Arrays.hashCode(arguments);
1601         }
1602     }
1603 
1604     /** Return the index of the last name which contains n as an argument.
1605      *  Return -1 if the name is not used.  Return names.length if it is the return value.
1606      */
1607     int lastUseIndex(Name n) {
1608         int ni = n.index, nmax = names.length;
1609         assert(names[ni] == n);
1610         if (result == ni)  return nmax;  // live all the way beyond the end
1611         for (int i = nmax; --i > ni; ) {
1612             if (names[i].lastUseIndex(n) >= 0)
1613                 return i;
1614         }
1615         return -1;
1616     }
1617 
1618     /** Return the number of times n is used as an argument or return value. */
1619     int useCount(Name n) {
1620         int nmax = names.length;
1621         int end = lastUseIndex(n);
1622         if (end < 0)  return 0;
1623         int count = 0;
1624         if (end == nmax) { count++; end--; }
1625         int beg = n.index() + 1;
1626         if (beg < arity)  beg = arity;
1627         for (int i = beg; i <= end; i++) {
1628             count += names[i].useCount(n);
1629         }
1630         return count;
1631     }
1632 
1633     static Name argument(int which, BasicType type) {
1634         if (which >= INTERNED_ARGUMENT_LIMIT)
1635             return new Name(which, type);
1636         return INTERNED_ARGUMENTS[type.ordinal()][which];
1637     }
1638     static Name internArgument(Name n) {
1639         assert(n.isParam()) : "not param: " + n;
1640         assert(n.index < INTERNED_ARGUMENT_LIMIT);
1641         if (n.constraint != null)  return n;
1642         return argument(n.index, n.type);
1643     }
1644     static Name[] arguments(int extra, MethodType types) {
1645         int length = types.parameterCount();
1646         Name[] names = new Name[length + extra];
1647         for (int i = 0; i < length; i++)
1648             names[i] = argument(i, basicType(types.parameterType(i)));
1649         return names;
1650     }
1651     static final int INTERNED_ARGUMENT_LIMIT = 10;
1652     private static final Name[][] INTERNED_ARGUMENTS
1653             = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1654     static {
1655         for (BasicType type : BasicType.ARG_TYPES) {
1656             int ord = type.ordinal();
1657             for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1658                 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1659             }
1660         }
1661     }
1662 
1663     private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1664 
1665     static LambdaForm identityForm(BasicType type) {
1666         int ord = type.ordinal();
1667         LambdaForm form = LF_identity[ord];
1668         if (form != null) {
1669             return form;
1670         }
1671         createFormsFor(type);
1672         return LF_identity[ord];
1673     }
1674 
1675     static LambdaForm zeroForm(BasicType type) {
1676         int ord = type.ordinal();
1677         LambdaForm form = LF_zero[ord];
1678         if (form != null) {
1679             return form;
1680         }
1681         createFormsFor(type);
1682         return LF_zero[ord];
1683     }
1684 
1685     static NamedFunction identity(BasicType type) {
1686         int ord = type.ordinal();
1687         NamedFunction function = NF_identity[ord];
1688         if (function != null) {
1689             return function;
1690         }
1691         createFormsFor(type);
1692         return NF_identity[ord];
1693     }
1694 
1695     static NamedFunction constantZero(BasicType type) {
1696         int ord = type.ordinal();
1697         NamedFunction function = NF_zero[ord];
1698         if (function != null) {
1699             return function;
1700         }
1701         createFormsFor(type);
1702         return NF_zero[ord];
1703     }
1704 
1705     private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1706     private static final @Stable LambdaForm[] LF_zero = new LambdaForm[TYPE_LIMIT];
1707     private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1708     private static final @Stable NamedFunction[] NF_zero = new NamedFunction[TYPE_LIMIT];
1709 
1710     private static synchronized void createFormsFor(BasicType type) {
1711         final int ord = type.ordinal();
1712         LambdaForm idForm = LF_identity[ord];
1713         if (idForm != null) {
1714             return;
1715         }
1716         char btChar = type.basicTypeChar();
1717         boolean isVoid = (type == V_TYPE);
1718         Class<?> btClass = type.btClass;
1719         MethodType zeType = MethodType.methodType(btClass);
1720         MethodType idType = (isVoid) ? zeType : MethodType.methodType(btClass, btClass);
1721 
1722         // Look up symbolic names.  It might not be necessary to have these,
1723         // but if we need to emit direct references to bytecodes, it helps.
1724         // Zero is built from a call to an identity function with a constant zero input.
1725         MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1726         MemberName zeMem = null;
1727         try {
1728             idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, NoSuchMethodException.class);
1729             if (!isVoid) {
1730                 zeMem = new MemberName(LambdaForm.class, "zero_"+btChar, zeType, REF_invokeStatic);
1731                 zeMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, zeMem, null, NoSuchMethodException.class);
1732             }
1733         } catch (IllegalAccessException|NoSuchMethodException ex) {
1734             throw newInternalError(ex);
1735         }
1736 
1737         NamedFunction idFun;
1738         LambdaForm zeForm;
1739         NamedFunction zeFun;
1740 
1741         // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1742         // bootstrap dependency on this method in case we're interpreting LFs
1743         if (isVoid) {
1744             Name[] idNames = new Name[] { argument(0, L_TYPE) };
1745             idForm = new LambdaForm(1, idNames, VOID_RESULT, Kind.IDENTITY);
1746             idForm.compileToBytecode();
1747             idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1748 
1749             zeForm = idForm;
1750             zeFun = idFun;
1751         } else {
1752             Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1753             idForm = new LambdaForm(2, idNames, 1, Kind.IDENTITY);
1754             idForm.compileToBytecode();
1755             idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm),
1756                         MethodHandleImpl.Intrinsic.IDENTITY);
1757 
1758             Object zeValue = Wrapper.forBasicType(btChar).zero();
1759             Name[] zeNames = new Name[] { argument(0, L_TYPE), new Name(idFun, zeValue) };
1760             zeForm = new LambdaForm(1, zeNames, 1, Kind.ZERO);
1761             zeForm.compileToBytecode();
1762             zeFun = new NamedFunction(zeMem, SimpleMethodHandle.make(zeMem.getInvocationType(), zeForm),
1763                     MethodHandleImpl.Intrinsic.ZERO);
1764         }
1765 
1766         LF_zero[ord] = zeForm;
1767         NF_zero[ord] = zeFun;
1768         LF_identity[ord] = idForm;
1769         NF_identity[ord] = idFun;
1770 
1771         assert(idFun.isIdentity());
1772         assert(zeFun.isConstantZero());
1773         assert(new Name(zeFun).isConstantZero());
1774     }
1775 
1776     // Avoid appealing to ValueConversions at bootstrap time:
1777     private static int identity_I(int x) { return x; }
1778     private static long identity_J(long x) { return x; }
1779     private static float identity_F(float x) { return x; }
1780     private static double identity_D(double x) { return x; }
1781     private static Object identity_L(Object x) { return x; }
1782     private static void identity_V() { return; }
1783     private static int zero_I() { return 0; }
1784     private static long zero_J() { return 0; }
1785     private static float zero_F() { return 0; }
1786     private static double zero_D() { return 0; }
1787     private static Object zero_L() { return null; }
1788 
1789     /**
1790      * Internal marker for byte-compiled LambdaForms.
1791      */
1792     /*non-public*/
1793     @Target(ElementType.METHOD)
1794     @Retention(RetentionPolicy.RUNTIME)
1795     @interface Compiled {
1796     }
1797 
1798     /**
1799      * Internal marker for LambdaForm interpreter frames.
1800      */
1801     /*non-public*/
1802     @Target(ElementType.METHOD)
1803     @Retention(RetentionPolicy.RUNTIME)
1804     @interface Hidden {
1805     }
1806 
1807     private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1808     private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1809     static {
1810         if (debugEnabled()) {
1811             DEBUG_NAME_COUNTERS = new HashMap<>();
1812             DEBUG_NAMES = new HashMap<>();
1813         } else {
1814             DEBUG_NAME_COUNTERS = null;
1815             DEBUG_NAMES = null;
1816         }
1817     }
1818 
1819     static {
1820         // The Holder class will contain pre-generated forms resolved
1821         // using MemberName.getFactory(). However, that doesn't initialize the
1822         // class, which subtly breaks inlining etc. By forcing
1823         // initialization of the Holder class we avoid these issues.
1824         UNSAFE.ensureClassInitialized(Holder.class);
1825     }
1826 
1827     /* Placeholder class for zero and identity forms generated ahead of time */
1828     final class Holder {}
1829 
1830     // The following hack is necessary in order to suppress TRACE_INTERPRETER
1831     // during execution of the static initializes of this class.
1832     // Turning on TRACE_INTERPRETER too early will cause
1833     // stack overflows and other misbehavior during attempts to trace events
1834     // that occur during LambdaForm.<clinit>.
1835     // Therefore, do not move this line higher in this file, and do not remove.
1836     private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1837 }
--- EOF ---