1 /*
   2  * Copyright (c) 2008, 2011, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/symbolTable.hpp"
  27 #include "compiler/compileBroker.hpp"
  28 #include "interpreter/interpreter.hpp"
  29 #include "interpreter/oopMapCache.hpp"
  30 #include "memory/allocation.inline.hpp"
  31 #include "memory/oopFactory.hpp"
  32 #include "prims/methodHandles.hpp"
  33 #include "prims/methodHandleWalk.hpp"
  34 #include "runtime/compilationPolicy.hpp"
  35 #include "runtime/javaCalls.hpp"
  36 #include "runtime/reflection.hpp"
  37 #include "runtime/signature.hpp"
  38 #include "runtime/stubRoutines.hpp"
  39 
  40 /*
  41  * JSR 292 reference implementation: method handles
  42  */
  43 
  44 bool MethodHandles::_enabled = false; // set true after successful native linkage
  45 
  46 MethodHandleEntry* MethodHandles::_entries[MethodHandles::_EK_LIMIT] = {NULL};
  47 const char*        MethodHandles::_entry_names[_EK_LIMIT+1] = {
  48   "raise_exception",
  49   "invokestatic",               // how a MH emulates invokestatic
  50   "invokespecial",              // ditto for the other invokes...
  51   "invokevirtual",
  52   "invokeinterface",
  53   "bound_ref",                  // these are for BMH...
  54   "bound_int",
  55   "bound_long",
  56   "bound_ref_direct",           // (direct versions have a direct methodOop)
  57   "bound_int_direct",
  58   "bound_long_direct",
  59 
  60   // starting at _adapter_mh_first:
  61   "adapter_retype_only",       // these are for AMH...
  62   "adapter_retype_raw",
  63   "adapter_check_cast",
  64   "adapter_prim_to_prim",
  65   "adapter_ref_to_prim",
  66   "adapter_prim_to_ref",
  67   "adapter_swap_args",
  68   "adapter_rot_args",
  69   "adapter_dup_args",
  70   "adapter_drop_args",
  71   "adapter_collect_args",
  72   "adapter_spread_args",
  73   "adapter_fold_args",
  74   "adapter_unused_13",
  75 
  76   // optimized adapter types:
  77   "adapter_swap_args/1",
  78   "adapter_swap_args/2",
  79   "adapter_rot_args/1,up",
  80   "adapter_rot_args/1,down",
  81   "adapter_rot_args/2,up",
  82   "adapter_rot_args/2,down",
  83   "adapter_prim_to_prim/i2i",
  84   "adapter_prim_to_prim/l2i",
  85   "adapter_prim_to_prim/d2f",
  86   "adapter_prim_to_prim/i2l",
  87   "adapter_prim_to_prim/f2d",
  88   "adapter_ref_to_prim/unboxi",
  89   "adapter_ref_to_prim/unboxl",
  90 
  91   // return value handlers for collect/filter/fold adapters:
  92   "return/ref",
  93   "return/int",
  94   "return/long",
  95   "return/float",
  96   "return/double",
  97   "return/void",
  98   "return/S0/ref",
  99   "return/S1/ref",
 100   "return/S2/ref",
 101   "return/S3/ref",
 102   "return/S4/ref",
 103   "return/S5/ref",
 104   "return/any",
 105 
 106   // spreading (array length cases 0, 1, ...)
 107   "adapter_spread/0",
 108   "adapter_spread/1/ref",
 109   "adapter_spread/2/ref",
 110   "adapter_spread/3/ref",
 111   "adapter_spread/4/ref",
 112   "adapter_spread/5/ref",
 113   "adapter_spread/ref",
 114   "adapter_spread/byte",
 115   "adapter_spread/char",
 116   "adapter_spread/short",
 117   "adapter_spread/int",
 118   "adapter_spread/long",
 119   "adapter_spread/float",
 120   "adapter_spread/double",
 121 
 122   // blocking filter/collect conversions:
 123   "adapter_collect/ref",
 124   "adapter_collect/int",
 125   "adapter_collect/long",
 126   "adapter_collect/float",
 127   "adapter_collect/double",
 128   "adapter_collect/void",
 129   "adapter_collect/0/ref",
 130   "adapter_collect/1/ref",
 131   "adapter_collect/2/ref",
 132   "adapter_collect/3/ref",
 133   "adapter_collect/4/ref",
 134   "adapter_collect/5/ref",
 135   "adapter_filter/S0/ref",
 136   "adapter_filter/S1/ref",
 137   "adapter_filter/S2/ref",
 138   "adapter_filter/S3/ref",
 139   "adapter_filter/S4/ref",
 140   "adapter_filter/S5/ref",
 141   "adapter_collect/2/S0/ref",
 142   "adapter_collect/2/S1/ref",
 143   "adapter_collect/2/S2/ref",
 144   "adapter_collect/2/S3/ref",
 145   "adapter_collect/2/S4/ref",
 146   "adapter_collect/2/S5/ref",
 147 
 148   // blocking fold conversions:
 149   "adapter_fold/ref",
 150   "adapter_fold/int",
 151   "adapter_fold/long",
 152   "adapter_fold/float",
 153   "adapter_fold/double",
 154   "adapter_fold/void",
 155   "adapter_fold/1/ref",
 156   "adapter_fold/2/ref",
 157   "adapter_fold/3/ref",
 158   "adapter_fold/4/ref",
 159   "adapter_fold/5/ref",
 160 
 161   NULL
 162 };
 163 
 164 // Adapters.
 165 MethodHandlesAdapterBlob* MethodHandles::_adapter_code = NULL;
 166 
 167 jobject MethodHandles::_raise_exception_method;
 168 
 169 address MethodHandles::_adapter_return_handlers[CONV_TYPE_MASK+1];
 170 
 171 #ifdef ASSERT
 172 bool MethodHandles::spot_check_entry_names() {
 173   assert(!strcmp(entry_name(_invokestatic_mh), "invokestatic"), "");
 174   assert(!strcmp(entry_name(_bound_ref_mh), "bound_ref"), "");
 175   assert(!strcmp(entry_name(_adapter_retype_only), "adapter_retype_only"), "");
 176   assert(!strcmp(entry_name(_adapter_fold_args), "adapter_fold_args"), "");
 177   assert(!strcmp(entry_name(_adapter_opt_unboxi), "adapter_ref_to_prim/unboxi"), "");
 178   assert(!strcmp(entry_name(_adapter_opt_spread_char), "adapter_spread/char"), "");
 179   assert(!strcmp(entry_name(_adapter_opt_spread_double), "adapter_spread/double"), "");
 180   assert(!strcmp(entry_name(_adapter_opt_collect_int), "adapter_collect/int"), "");
 181   assert(!strcmp(entry_name(_adapter_opt_collect_0_ref), "adapter_collect/0/ref"), "");
 182   assert(!strcmp(entry_name(_adapter_opt_collect_2_S3_ref), "adapter_collect/2/S3/ref"), "");
 183   assert(!strcmp(entry_name(_adapter_opt_filter_S5_ref), "adapter_filter/S5/ref"), "");
 184   assert(!strcmp(entry_name(_adapter_opt_fold_3_ref), "adapter_fold/3/ref"), "");
 185   assert(!strcmp(entry_name(_adapter_opt_fold_void), "adapter_fold/void"), "");
 186   return true;
 187 }
 188 #endif
 189 
 190 
 191 //------------------------------------------------------------------------------
 192 // MethodHandles::generate_adapters
 193 //
 194 void MethodHandles::generate_adapters() {
 195 #ifdef TARGET_ARCH_NYI_6939861
 196   if (FLAG_IS_DEFAULT(UseRicochetFrames))  UseRicochetFrames = false;
 197 #endif
 198   if (!EnableInvokeDynamic || SystemDictionary::MethodHandle_klass() == NULL)  return;
 199 
 200   assert(_adapter_code == NULL, "generate only once");
 201 
 202   ResourceMark rm;
 203   TraceTime timer("MethodHandles adapters generation", TraceStartupTime);
 204   _adapter_code = MethodHandlesAdapterBlob::create(adapter_code_size);
 205   if (_adapter_code == NULL)
 206     vm_exit_out_of_memory(adapter_code_size, "CodeCache: no room for MethodHandles adapters");
 207   CodeBuffer code(_adapter_code);
 208   MethodHandlesAdapterGenerator g(&code);
 209   g.generate();
 210 }
 211 
 212 //------------------------------------------------------------------------------
 213 // MethodHandlesAdapterGenerator::generate
 214 //
 215 void MethodHandlesAdapterGenerator::generate() {
 216   // Generate generic method handle adapters.
 217   for (MethodHandles::EntryKind ek = MethodHandles::_EK_FIRST;
 218        ek < MethodHandles::_EK_LIMIT;
 219        ek = MethodHandles::EntryKind(1 + (int)ek)) {
 220     if (MethodHandles::ek_supported(ek)) {
 221       StubCodeMark mark(this, "MethodHandle", MethodHandles::entry_name(ek));
 222       MethodHandles::generate_method_handle_stub(_masm, ek);
 223     }
 224   }
 225 }
 226 
 227 
 228 #ifdef TARGET_ARCH_NYI_6939861
 229 // these defs belong in methodHandles_<arch>.cpp
 230 frame MethodHandles::ricochet_frame_sender(const frame& fr, RegisterMap *map) {
 231   ShouldNotCallThis();
 232   return fr;
 233 }
 234 void MethodHandles::ricochet_frame_oops_do(const frame& fr, OopClosure* f, const RegisterMap* reg_map) {
 235   ShouldNotCallThis();
 236 }
 237 #endif //TARGET_ARCH_NYI_6939861
 238 
 239 
 240 //------------------------------------------------------------------------------
 241 // MethodHandles::ek_supported
 242 //
 243 bool MethodHandles::ek_supported(MethodHandles::EntryKind ek) {
 244   MethodHandles::EntryKind ek_orig = MethodHandles::ek_original_kind(ek);
 245   switch (ek_orig) {
 246   case _adapter_unused_13:
 247     return false;  // not defined yet
 248   case _adapter_prim_to_ref:
 249     return UseRicochetFrames && conv_op_supported(java_lang_invoke_AdapterMethodHandle::OP_PRIM_TO_REF);
 250   case _adapter_collect_args:
 251     return UseRicochetFrames && conv_op_supported(java_lang_invoke_AdapterMethodHandle::OP_COLLECT_ARGS);
 252   case _adapter_fold_args:
 253     return UseRicochetFrames && conv_op_supported(java_lang_invoke_AdapterMethodHandle::OP_FOLD_ARGS);
 254   case _adapter_opt_return_any:
 255     return UseRicochetFrames;
 256 #ifdef TARGET_ARCH_NYI_6939861
 257   // ports before 6939861 supported only three kinds of spread ops
 258   case _adapter_spread_args:
 259     // restrict spreads to three kinds:
 260     switch (ek) {
 261     case _adapter_opt_spread_0:
 262     case _adapter_opt_spread_1:
 263     case _adapter_opt_spread_more:
 264       break;
 265     default:
 266       return false;
 267       break;
 268     }
 269     break;
 270 #endif //TARGET_ARCH_NYI_6939861
 271   }
 272   return true;
 273 }
 274 
 275 
 276 void MethodHandles::set_enabled(bool z) {
 277   if (_enabled != z) {
 278     guarantee(z && EnableInvokeDynamic, "can only enable once, and only if -XX:+EnableInvokeDynamic");
 279     _enabled = z;
 280   }
 281 }
 282 
 283 // Note: A method which does not have a TRAPS argument cannot block in the GC
 284 // or throw exceptions.  Such methods are used in this file to do something quick
 285 // and local, like parse a data structure.  For speed, such methods work on plain
 286 // oops, not handles.  Trapping methods uniformly operate on handles.
 287 
 288 methodHandle MethodHandles::decode_vmtarget(oop vmtarget, int vmindex, oop mtype,
 289                                             KlassHandle& receiver_limit_result, int& decode_flags_result) {
 290   if (vmtarget == NULL)  return methodHandle();
 291   assert(methodOopDesc::nonvirtual_vtable_index < 0, "encoding");
 292   if (vmindex < 0) {
 293     // this DMH performs no dispatch; it is directly bound to a methodOop
 294     // A MemberName may either be directly bound to a methodOop,
 295     // or it may use the klass/index form; both forms mean the same thing.
 296     methodOop m = decode_methodOop(methodOop(vmtarget), decode_flags_result);
 297     if ((decode_flags_result & _dmf_has_receiver) != 0
 298         && java_lang_invoke_MethodType::is_instance(mtype)) {
 299       // Extract receiver type restriction from mtype.ptypes[0].
 300       objArrayOop ptypes = java_lang_invoke_MethodType::ptypes(mtype);
 301       oop ptype0 = (ptypes == NULL || ptypes->length() < 1) ? oop(NULL) : ptypes->obj_at(0);
 302       if (java_lang_Class::is_instance(ptype0))
 303         receiver_limit_result = java_lang_Class::as_klassOop(ptype0);
 304     }
 305     if (vmindex == methodOopDesc::nonvirtual_vtable_index) {
 306       // this DMH can be an "invokespecial" version
 307       decode_flags_result &= ~_dmf_does_dispatch;
 308     } else {
 309       assert(vmindex == methodOopDesc::invalid_vtable_index, "random vmindex?");
 310     }
 311     return m;
 312   } else {
 313     assert(vmtarget->is_klass(), "must be class or interface");
 314     decode_flags_result |= MethodHandles::_dmf_does_dispatch;
 315     decode_flags_result |= MethodHandles::_dmf_has_receiver;
 316     receiver_limit_result = (klassOop)vmtarget;
 317     Klass* tk = Klass::cast((klassOop)vmtarget);
 318     if (tk->is_interface()) {
 319       // an itable linkage is <interface, itable index>
 320       decode_flags_result |= MethodHandles::_dmf_from_interface;
 321       return klassItable::method_for_itable_index((klassOop)vmtarget, vmindex);
 322     } else {
 323       if (!tk->oop_is_instance())
 324         tk = instanceKlass::cast(SystemDictionary::Object_klass());
 325       return ((instanceKlass*)tk)->method_at_vtable(vmindex);
 326     }
 327   }
 328 }
 329 
 330 // MemberName and DirectMethodHandle have the same linkage to the JVM internals.
 331 // (MemberName is the non-operational name used for queries and setup.)
 332 
 333 methodHandle MethodHandles::decode_DirectMethodHandle(oop mh, KlassHandle& receiver_limit_result, int& decode_flags_result) {
 334   oop vmtarget = java_lang_invoke_DirectMethodHandle::vmtarget(mh);
 335   int vmindex  = java_lang_invoke_DirectMethodHandle::vmindex(mh);
 336   oop mtype    = java_lang_invoke_DirectMethodHandle::type(mh);
 337   return decode_vmtarget(vmtarget, vmindex, mtype, receiver_limit_result, decode_flags_result);
 338 }
 339 
 340 methodHandle MethodHandles::decode_BoundMethodHandle(oop mh, KlassHandle& receiver_limit_result, int& decode_flags_result) {
 341   assert(java_lang_invoke_BoundMethodHandle::is_instance(mh), "");
 342   assert(mh->klass() != SystemDictionary::AdapterMethodHandle_klass(), "");
 343   for (oop bmh = mh;;) {
 344     // Bound MHs can be stacked to bind several arguments.
 345     oop target = java_lang_invoke_MethodHandle::vmtarget(bmh);
 346     if (target == NULL)  return methodHandle();
 347     decode_flags_result |= MethodHandles::_dmf_binds_argument;
 348     klassOop tk = target->klass();
 349     if (tk == SystemDictionary::BoundMethodHandle_klass()) {
 350       bmh = target;
 351       continue;
 352     } else {
 353       if (java_lang_invoke_MethodHandle::is_subclass(tk)) {
 354         //assert(tk == SystemDictionary::DirectMethodHandle_klass(), "end of BMH chain must be DMH");
 355         return decode_MethodHandle(target, receiver_limit_result, decode_flags_result);
 356       } else {
 357         // Optimized case:  binding a receiver to a non-dispatched DMH
 358         // short-circuits directly to the methodOop.
 359         // (It might be another argument besides a receiver also.)
 360         assert(target->is_method(), "must be a simple method");
 361         decode_flags_result |= MethodHandles::_dmf_binds_method;
 362         methodOop m = (methodOop) target;
 363         if (!m->is_static())
 364           decode_flags_result |= MethodHandles::_dmf_has_receiver;
 365         return m;
 366       }
 367     }
 368   }
 369 }
 370 
 371 methodHandle MethodHandles::decode_AdapterMethodHandle(oop mh, KlassHandle& receiver_limit_result, int& decode_flags_result) {
 372   assert(mh->klass() == SystemDictionary::AdapterMethodHandle_klass(), "");
 373   for (oop amh = mh;;) {
 374     // Adapter MHs can be stacked to convert several arguments.
 375     int conv_op = adapter_conversion_op(java_lang_invoke_AdapterMethodHandle::conversion(amh));
 376     decode_flags_result |= (_dmf_adapter_lsb << conv_op) & _DMF_ADAPTER_MASK;
 377     oop target = java_lang_invoke_MethodHandle::vmtarget(amh);
 378     if (target == NULL)  return methodHandle();
 379     klassOop tk = target->klass();
 380     if (tk == SystemDictionary::AdapterMethodHandle_klass()) {
 381       amh = target;
 382       continue;
 383     } else {
 384       // must be a BMH (which will bind some more arguments) or a DMH (for the final call)
 385       return MethodHandles::decode_MethodHandle(target, receiver_limit_result, decode_flags_result);
 386     }
 387   }
 388 }
 389 
 390 methodHandle MethodHandles::decode_MethodHandle(oop mh, KlassHandle& receiver_limit_result, int& decode_flags_result) {
 391   if (mh == NULL)  return methodHandle();
 392   klassOop mhk = mh->klass();
 393   assert(java_lang_invoke_MethodHandle::is_subclass(mhk), "must be a MethodHandle");
 394   if (mhk == SystemDictionary::DirectMethodHandle_klass()) {
 395     return decode_DirectMethodHandle(mh, receiver_limit_result, decode_flags_result);
 396   } else if (mhk == SystemDictionary::BoundMethodHandle_klass()) {
 397     return decode_BoundMethodHandle(mh, receiver_limit_result, decode_flags_result);
 398   } else if (mhk == SystemDictionary::AdapterMethodHandle_klass()) {
 399     return decode_AdapterMethodHandle(mh, receiver_limit_result, decode_flags_result);
 400   } else if (java_lang_invoke_BoundMethodHandle::is_subclass(mhk)) {
 401     // could be a JavaMethodHandle (but not an adapter MH)
 402     return decode_BoundMethodHandle(mh, receiver_limit_result, decode_flags_result);
 403   } else {
 404     assert(false, "cannot parse this MH");
 405     return methodHandle();  // random MH?
 406   }
 407 }
 408 
 409 methodOop MethodHandles::decode_methodOop(methodOop m, int& decode_flags_result) {
 410   assert(m->is_method(), "");
 411   if (m->is_static()) {
 412     // check that signature begins '(L' or '([' (not '(I', '()', etc.)
 413     Symbol* sig = m->signature();
 414     BasicType recv_bt = char2type(sig->byte_at(1));
 415     // Note: recv_bt might be T_ILLEGAL if byte_at(2) is ')'
 416     assert(sig->byte_at(0) == '(', "must be method sig");
 417 //     if (recv_bt == T_OBJECT || recv_bt == T_ARRAY)
 418 //       decode_flags_result |= _dmf_has_receiver;
 419   } else {
 420     // non-static method
 421     decode_flags_result |= _dmf_has_receiver;
 422     if (!m->can_be_statically_bound() && !m->is_initializer()) {
 423       decode_flags_result |= _dmf_does_dispatch;
 424       if (Klass::cast(m->method_holder())->is_interface())
 425         decode_flags_result |= _dmf_from_interface;
 426     }
 427   }
 428   return m;
 429 }
 430 
 431 
 432 // A trusted party is handing us a cookie to determine a method.
 433 // Let's boil it down to the method oop they really want.
 434 methodHandle MethodHandles::decode_method(oop x, KlassHandle& receiver_limit_result, int& decode_flags_result) {
 435   decode_flags_result = 0;
 436   receiver_limit_result = KlassHandle();
 437   klassOop xk = x->klass();
 438   if (xk == Universe::methodKlassObj()) {
 439     return decode_methodOop((methodOop) x, decode_flags_result);
 440   } else if (xk == SystemDictionary::MemberName_klass()) {
 441     // Note: This only works if the MemberName has already been resolved.
 442     return decode_MemberName(x, receiver_limit_result, decode_flags_result);
 443   } else if (java_lang_invoke_MethodHandle::is_subclass(xk)) {
 444     return decode_MethodHandle(x, receiver_limit_result, decode_flags_result);
 445   } else if (xk == SystemDictionary::reflect_Method_klass()) {
 446     oop clazz  = java_lang_reflect_Method::clazz(x);
 447     int slot   = java_lang_reflect_Method::slot(x);
 448     klassOop k = java_lang_Class::as_klassOop(clazz);
 449     if (k != NULL && Klass::cast(k)->oop_is_instance())
 450       return decode_methodOop(instanceKlass::cast(k)->method_with_idnum(slot),
 451                               decode_flags_result);
 452   } else if (xk == SystemDictionary::reflect_Constructor_klass()) {
 453     oop clazz  = java_lang_reflect_Constructor::clazz(x);
 454     int slot   = java_lang_reflect_Constructor::slot(x);
 455     klassOop k = java_lang_Class::as_klassOop(clazz);
 456     if (k != NULL && Klass::cast(k)->oop_is_instance())
 457       return decode_methodOop(instanceKlass::cast(k)->method_with_idnum(slot),
 458                               decode_flags_result);
 459   } else {
 460     // unrecognized object
 461     assert(!x->is_method(), "already checked");
 462     assert(!java_lang_invoke_MemberName::is_instance(x), "already checked");
 463   }
 464   return methodHandle();
 465 }
 466 
 467 
 468 int MethodHandles::decode_MethodHandle_stack_pushes(oop mh) {
 469   if (mh->klass() == SystemDictionary::DirectMethodHandle_klass())
 470     return 0;                   // no push/pop
 471   int this_vmslots = java_lang_invoke_MethodHandle::vmslots(mh);
 472   int last_vmslots = 0;
 473   oop last_mh = mh;
 474   for (;;) {
 475     oop target = java_lang_invoke_MethodHandle::vmtarget(last_mh);
 476     if (target->klass() == SystemDictionary::DirectMethodHandle_klass()) {
 477       last_vmslots = java_lang_invoke_MethodHandle::vmslots(target);
 478       break;
 479     } else if (!java_lang_invoke_MethodHandle::is_instance(target)) {
 480       // might be klass or method
 481       assert(target->is_method(), "must get here with a direct ref to method");
 482       last_vmslots = methodOop(target)->size_of_parameters();
 483       break;
 484     }
 485     last_mh = target;
 486   }
 487   // If I am called with fewer VM slots than my ultimate callee,
 488   // it must be that I push the additionally needed slots.
 489   // Likewise if am called with more VM slots, I will pop them.
 490   return (last_vmslots - this_vmslots);
 491 }
 492 
 493 
 494 // MemberName support
 495 
 496 // import java_lang_invoke_MemberName.*
 497 enum {
 498   IS_METHOD      = java_lang_invoke_MemberName::MN_IS_METHOD,
 499   IS_CONSTRUCTOR = java_lang_invoke_MemberName::MN_IS_CONSTRUCTOR,
 500   IS_FIELD       = java_lang_invoke_MemberName::MN_IS_FIELD,
 501   IS_TYPE        = java_lang_invoke_MemberName::MN_IS_TYPE,
 502   SEARCH_SUPERCLASSES = java_lang_invoke_MemberName::MN_SEARCH_SUPERCLASSES,
 503   SEARCH_INTERFACES   = java_lang_invoke_MemberName::MN_SEARCH_INTERFACES,
 504   ALL_KINDS      = IS_METHOD | IS_CONSTRUCTOR | IS_FIELD | IS_TYPE,
 505   VM_INDEX_UNINITIALIZED = java_lang_invoke_MemberName::VM_INDEX_UNINITIALIZED
 506 };
 507 
 508 Handle MethodHandles::new_MemberName(TRAPS) {
 509   Handle empty;
 510   instanceKlassHandle k(THREAD, SystemDictionary::MemberName_klass());
 511   if (!k->is_initialized())  k->initialize(CHECK_(empty));
 512   return Handle(THREAD, k->allocate_instance(THREAD));
 513 }
 514 
 515 void MethodHandles::init_MemberName(oop mname_oop, oop target_oop) {
 516   if (target_oop->klass() == SystemDictionary::reflect_Field_klass()) {
 517     oop clazz = java_lang_reflect_Field::clazz(target_oop); // fd.field_holder()
 518     int slot  = java_lang_reflect_Field::slot(target_oop);  // fd.index()
 519     int mods  = java_lang_reflect_Field::modifiers(target_oop);
 520     klassOop k = java_lang_Class::as_klassOop(clazz);
 521     int offset = instanceKlass::cast(k)->offset_from_fields(slot);
 522     init_MemberName(mname_oop, k, accessFlags_from(mods), offset);
 523   } else {
 524     KlassHandle receiver_limit; int decode_flags = 0;
 525     methodHandle m = MethodHandles::decode_method(target_oop, receiver_limit, decode_flags);
 526     bool do_dispatch = ((decode_flags & MethodHandles::_dmf_does_dispatch) != 0);
 527     init_MemberName(mname_oop, m(), do_dispatch);
 528   }
 529 }
 530 
 531 void MethodHandles::init_MemberName(oop mname_oop, methodOop m, bool do_dispatch) {
 532   int flags = ((m->is_initializer() ? IS_CONSTRUCTOR : IS_METHOD)
 533                | (jushort)( m->access_flags().as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS ));
 534   oop vmtarget = m;
 535   int vmindex  = methodOopDesc::invalid_vtable_index;  // implies no info yet
 536   if (!do_dispatch || (flags & IS_CONSTRUCTOR) || m->can_be_statically_bound())
 537     vmindex = methodOopDesc::nonvirtual_vtable_index; // implies never any dispatch
 538   assert(vmindex != VM_INDEX_UNINITIALIZED, "Java sentinel value");
 539   java_lang_invoke_MemberName::set_vmtarget(mname_oop, vmtarget);
 540   java_lang_invoke_MemberName::set_vmindex(mname_oop,  vmindex);
 541   java_lang_invoke_MemberName::set_flags(mname_oop,    flags);
 542   java_lang_invoke_MemberName::set_clazz(mname_oop,    Klass::cast(m->method_holder())->java_mirror());
 543 }
 544 
 545 void MethodHandles::init_MemberName(oop mname_oop, klassOop field_holder, AccessFlags mods, int offset) {
 546   int flags = (IS_FIELD | (jushort)( mods.as_short() & JVM_RECOGNIZED_FIELD_MODIFIERS ));
 547   oop vmtarget = field_holder;
 548   int vmindex  = offset;  // determines the field uniquely when combined with static bit
 549   assert(vmindex != VM_INDEX_UNINITIALIZED, "bad alias on vmindex");
 550   java_lang_invoke_MemberName::set_vmtarget(mname_oop, vmtarget);
 551   java_lang_invoke_MemberName::set_vmindex(mname_oop,  vmindex);
 552   java_lang_invoke_MemberName::set_flags(mname_oop,    flags);
 553   java_lang_invoke_MemberName::set_clazz(mname_oop,    Klass::cast(field_holder)->java_mirror());
 554 }
 555 
 556 
 557 methodHandle MethodHandles::decode_MemberName(oop mname, KlassHandle& receiver_limit_result, int& decode_flags_result) {
 558   methodHandle empty;
 559   int flags  = java_lang_invoke_MemberName::flags(mname);
 560   if ((flags & (IS_METHOD | IS_CONSTRUCTOR)) == 0)  return empty;  // not invocable
 561   oop vmtarget = java_lang_invoke_MemberName::vmtarget(mname);
 562   int vmindex  = java_lang_invoke_MemberName::vmindex(mname);
 563   if (vmindex == VM_INDEX_UNINITIALIZED)  return empty;  // not resolved
 564   methodHandle m = decode_vmtarget(vmtarget, vmindex, NULL, receiver_limit_result, decode_flags_result);
 565   oop clazz = java_lang_invoke_MemberName::clazz(mname);
 566   if (clazz != NULL && java_lang_Class::is_instance(clazz)) {
 567     klassOop klass = java_lang_Class::as_klassOop(clazz);
 568     if (klass != NULL)  receiver_limit_result = klass;
 569   }
 570   return m;
 571 }
 572 
 573 // convert the external string or reflective type to an internal signature
 574 Symbol* MethodHandles::convert_to_signature(oop type_str, bool polymorphic, TRAPS) {
 575   if (java_lang_invoke_MethodType::is_instance(type_str)) {
 576     return java_lang_invoke_MethodType::as_signature(type_str, polymorphic, CHECK_NULL);
 577   } else if (java_lang_Class::is_instance(type_str)) {
 578     return java_lang_Class::as_signature(type_str, false, CHECK_NULL);
 579   } else if (java_lang_String::is_instance(type_str)) {
 580     if (polymorphic) {
 581       return java_lang_String::as_symbol(type_str, CHECK_NULL);
 582     } else {
 583       return java_lang_String::as_symbol_or_null(type_str);
 584     }
 585   } else {
 586     THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized type", NULL);
 587   }
 588 }
 589 
 590 // An unresolved member name is a mere symbolic reference.
 591 // Resolving it plants a vmtarget/vmindex in it,
 592 // which refers dirctly to JVM internals.
 593 void MethodHandles::resolve_MemberName(Handle mname, TRAPS) {
 594   assert(java_lang_invoke_MemberName::is_instance(mname()), "");
 595 #ifdef ASSERT
 596   // If this assert throws, renegotiate the sentinel value used by the Java code,
 597   // so that it is distinct from any valid vtable index value, and any special
 598   // values defined in methodOopDesc::VtableIndexFlag.
 599   // The point of the slop is to give the Java code and the JVM some room
 600   // to independently specify sentinel values.
 601   const int sentinel_slop  = 10;
 602   const int sentinel_limit = methodOopDesc::highest_unused_vtable_index_value - sentinel_slop;
 603   assert(VM_INDEX_UNINITIALIZED < sentinel_limit, "Java sentinel != JVM sentinels");
 604 #endif
 605   if (java_lang_invoke_MemberName::vmindex(mname()) != VM_INDEX_UNINITIALIZED)
 606     return;  // already resolved
 607   Handle defc_oop(THREAD, java_lang_invoke_MemberName::clazz(mname()));
 608   Handle name_str(THREAD, java_lang_invoke_MemberName::name( mname()));
 609   Handle type_str(THREAD, java_lang_invoke_MemberName::type( mname()));
 610   int    flags    =       java_lang_invoke_MemberName::flags(mname());
 611 
 612   if (defc_oop.is_null() || name_str.is_null() || type_str.is_null()) {
 613     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "nothing to resolve");
 614   }
 615 
 616   instanceKlassHandle defc;
 617   {
 618     klassOop defc_klassOop = java_lang_Class::as_klassOop(defc_oop());
 619     if (defc_klassOop == NULL)  return;  // a primitive; no resolution possible
 620     if (!Klass::cast(defc_klassOop)->oop_is_instance()) {
 621       if (!Klass::cast(defc_klassOop)->oop_is_array())  return;
 622       defc_klassOop = SystemDictionary::Object_klass();
 623     }
 624     defc = instanceKlassHandle(THREAD, defc_klassOop);
 625   }
 626   if (defc.is_null()) {
 627     THROW_MSG(vmSymbols::java_lang_InternalError(), "primitive class");
 628   }
 629   defc->link_class(CHECK);  // possible safepoint
 630 
 631   // convert the external string name to an internal symbol
 632   TempNewSymbol name = java_lang_String::as_symbol_or_null(name_str());
 633   if (name == NULL)  return;  // no such name
 634   if (name == vmSymbols::class_initializer_name())
 635     return; // illegal name
 636 
 637   Handle polymorphic_method_type;
 638   bool polymorphic_signature = false;
 639   if ((flags & ALL_KINDS) == IS_METHOD &&
 640       (defc() == SystemDictionary::MethodHandle_klass() &&
 641        methodOopDesc::is_method_handle_invoke_name(name))) {
 642     polymorphic_signature = true;
 643   }
 644 
 645   // convert the external string or reflective type to an internal signature
 646   TempNewSymbol type = convert_to_signature(type_str(), polymorphic_signature, CHECK);
 647   if (java_lang_invoke_MethodType::is_instance(type_str()) && polymorphic_signature) {
 648     polymorphic_method_type = type_str;  // preserve exactly
 649   }
 650   if (type == NULL)  return;  // no such signature exists in the VM
 651 
 652   // Time to do the lookup.
 653   switch (flags & ALL_KINDS) {
 654   case IS_METHOD:
 655     {
 656       CallInfo result;
 657       {
 658         EXCEPTION_MARK;
 659         if ((flags & JVM_ACC_STATIC) != 0) {
 660           LinkResolver::resolve_static_call(result,
 661                         defc, name, type, KlassHandle(), false, false, THREAD);
 662         } else if (defc->is_interface()) {
 663           LinkResolver::resolve_interface_call(result, Handle(), defc,
 664                         defc, name, type, KlassHandle(), false, false, THREAD);
 665         } else {
 666           LinkResolver::resolve_virtual_call(result, Handle(), defc,
 667                         defc, name, type, KlassHandle(), false, false, THREAD);
 668         }
 669         if (HAS_PENDING_EXCEPTION) {
 670           CLEAR_PENDING_EXCEPTION;
 671           break;  // go to second chance
 672         }
 673       }
 674       methodHandle m = result.resolved_method();
 675       oop vmtarget = NULL;
 676       int vmindex = methodOopDesc::nonvirtual_vtable_index;
 677       if (defc->is_interface()) {
 678         vmindex = klassItable::compute_itable_index(m());
 679         assert(vmindex >= 0, "");
 680       } else if (result.has_vtable_index()) {
 681         vmindex = result.vtable_index();
 682         assert(vmindex >= 0, "");
 683       }
 684       assert(vmindex != VM_INDEX_UNINITIALIZED, "");
 685       if (vmindex < 0) {
 686         assert(result.is_statically_bound(), "");
 687         vmtarget = m();
 688       } else {
 689         vmtarget = result.resolved_klass()->as_klassOop();
 690       }
 691       int mods = (m->access_flags().as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS);
 692       java_lang_invoke_MemberName::set_vmtarget(mname(), vmtarget);
 693       java_lang_invoke_MemberName::set_vmindex(mname(),  vmindex);
 694       java_lang_invoke_MemberName::set_modifiers(mname(), mods);
 695       DEBUG_ONLY(KlassHandle junk1; int junk2);
 696       assert(decode_MemberName(mname(), junk1, junk2) == result.resolved_method(),
 697              "properly stored for later decoding");
 698       return;
 699     }
 700   case IS_CONSTRUCTOR:
 701     {
 702       CallInfo result;
 703       {
 704         EXCEPTION_MARK;
 705         if (name == vmSymbols::object_initializer_name()) {
 706           LinkResolver::resolve_special_call(result,
 707                         defc, name, type, KlassHandle(), false, THREAD);
 708         } else {
 709           break;                // will throw after end of switch
 710         }
 711         if (HAS_PENDING_EXCEPTION) {
 712           CLEAR_PENDING_EXCEPTION;
 713           return;
 714         }
 715       }
 716       assert(result.is_statically_bound(), "");
 717       methodHandle m = result.resolved_method();
 718       oop vmtarget = m();
 719       int vmindex  = methodOopDesc::nonvirtual_vtable_index;
 720       int mods     = (m->access_flags().as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS);
 721       java_lang_invoke_MemberName::set_vmtarget(mname(), vmtarget);
 722       java_lang_invoke_MemberName::set_vmindex(mname(),  vmindex);
 723       java_lang_invoke_MemberName::set_modifiers(mname(), mods);
 724       DEBUG_ONLY(KlassHandle junk1; int junk2);
 725       assert(decode_MemberName(mname(), junk1, junk2) == result.resolved_method(),
 726              "properly stored for later decoding");
 727       return;
 728     }
 729   case IS_FIELD:
 730     {
 731       // This is taken from LinkResolver::resolve_field, sans access checks.
 732       fieldDescriptor fd; // find_field initializes fd if found
 733       KlassHandle sel_klass(THREAD, instanceKlass::cast(defc())->find_field(name, type, &fd));
 734       // check if field exists; i.e., if a klass containing the field def has been selected
 735       if (sel_klass.is_null())  return;
 736       oop vmtarget = sel_klass->as_klassOop();
 737       int vmindex  = fd.offset();
 738       int mods     = (fd.access_flags().as_short() & JVM_RECOGNIZED_FIELD_MODIFIERS);
 739       if (vmindex == VM_INDEX_UNINITIALIZED)  break;  // should not happen
 740       java_lang_invoke_MemberName::set_vmtarget(mname(),  vmtarget);
 741       java_lang_invoke_MemberName::set_vmindex(mname(),   vmindex);
 742       java_lang_invoke_MemberName::set_modifiers(mname(), mods);
 743       return;
 744     }
 745   default:
 746     THROW_MSG(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format");
 747   }
 748 
 749   // Second chance.
 750   if (polymorphic_method_type.not_null()) {
 751     // Look on a non-null class loader.
 752     Handle cur_class_loader;
 753     const int nptypes = java_lang_invoke_MethodType::ptype_count(polymorphic_method_type());
 754     for (int i = 0; i <= nptypes; i++) {
 755       oop type_mirror;
 756       if (i < nptypes)  type_mirror = java_lang_invoke_MethodType::ptype(polymorphic_method_type(), i);
 757       else              type_mirror = java_lang_invoke_MethodType::rtype(polymorphic_method_type());
 758       klassOop example_type = java_lang_Class::as_klassOop(type_mirror);
 759       if (example_type == NULL)  continue;
 760       oop class_loader = Klass::cast(example_type)->class_loader();
 761       if (class_loader == NULL || class_loader == cur_class_loader())  continue;
 762       cur_class_loader = Handle(THREAD, class_loader);
 763       methodOop m = SystemDictionary::find_method_handle_invoke(name,
 764                                                                 type,
 765                                                                 KlassHandle(THREAD, example_type),
 766                                                                 THREAD);
 767       if (HAS_PENDING_EXCEPTION) {
 768         CLEAR_PENDING_EXCEPTION;
 769         m = NULL;
 770         // try again with a different class loader...
 771       }
 772       if (m != NULL &&
 773           m->is_method_handle_invoke() &&
 774           java_lang_invoke_MethodType::equals(polymorphic_method_type(), m->method_handle_type())) {
 775         int mods = (m->access_flags().as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS);
 776         java_lang_invoke_MemberName::set_vmtarget(mname(),  m);
 777         java_lang_invoke_MemberName::set_vmindex(mname(),   m->vtable_index());
 778         java_lang_invoke_MemberName::set_modifiers(mname(), mods);
 779         return;
 780       }
 781     }
 782   }
 783 }
 784 
 785 // Conversely, a member name which is only initialized from JVM internals
 786 // may have null defc, name, and type fields.
 787 // Resolving it plants a vmtarget/vmindex in it,
 788 // which refers directly to JVM internals.
 789 void MethodHandles::expand_MemberName(Handle mname, int suppress, TRAPS) {
 790   assert(java_lang_invoke_MemberName::is_instance(mname()), "");
 791   oop vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
 792   int vmindex  = java_lang_invoke_MemberName::vmindex(mname());
 793   if (vmtarget == NULL || vmindex == VM_INDEX_UNINITIALIZED) {
 794     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "nothing to expand");
 795   }
 796 
 797   bool have_defc = (java_lang_invoke_MemberName::clazz(mname()) != NULL);
 798   bool have_name = (java_lang_invoke_MemberName::name(mname()) != NULL);
 799   bool have_type = (java_lang_invoke_MemberName::type(mname()) != NULL);
 800   int flags      = java_lang_invoke_MemberName::flags(mname());
 801 
 802   if (suppress != 0) {
 803     if (suppress & _suppress_defc)  have_defc = true;
 804     if (suppress & _suppress_name)  have_name = true;
 805     if (suppress & _suppress_type)  have_type = true;
 806   }
 807 
 808   if (have_defc && have_name && have_type)  return;  // nothing needed
 809 
 810   switch (flags & ALL_KINDS) {
 811   case IS_METHOD:
 812   case IS_CONSTRUCTOR:
 813     {
 814       KlassHandle receiver_limit; int decode_flags = 0;
 815       methodHandle m = decode_vmtarget(vmtarget, vmindex, NULL, receiver_limit, decode_flags);
 816       if (m.is_null())  break;
 817       if (!have_defc) {
 818         klassOop defc = m->method_holder();
 819         if (receiver_limit.not_null() && receiver_limit() != defc
 820             && Klass::cast(receiver_limit())->is_subtype_of(defc))
 821           defc = receiver_limit();
 822         java_lang_invoke_MemberName::set_clazz(mname(), Klass::cast(defc)->java_mirror());
 823       }
 824       if (!have_name) {
 825         //not java_lang_String::create_from_symbol; let's intern member names
 826         Handle name = StringTable::intern(m->name(), CHECK);
 827         java_lang_invoke_MemberName::set_name(mname(), name());
 828       }
 829       if (!have_type) {
 830         Handle type = java_lang_String::create_from_symbol(m->signature(), CHECK);
 831         java_lang_invoke_MemberName::set_type(mname(), type());
 832       }
 833       return;
 834     }
 835   case IS_FIELD:
 836     {
 837       // This is taken from LinkResolver::resolve_field, sans access checks.
 838       if (!vmtarget->is_klass())  break;
 839       if (!Klass::cast((klassOop) vmtarget)->oop_is_instance())  break;
 840       instanceKlassHandle defc(THREAD, (klassOop) vmtarget);
 841       bool is_static = ((flags & JVM_ACC_STATIC) != 0);
 842       fieldDescriptor fd; // find_field initializes fd if found
 843       if (!defc->find_field_from_offset(vmindex, is_static, &fd))
 844         break;                  // cannot expand
 845       if (!have_defc) {
 846         java_lang_invoke_MemberName::set_clazz(mname(), defc->java_mirror());
 847       }
 848       if (!have_name) {
 849         //not java_lang_String::create_from_symbol; let's intern member names
 850         Handle name = StringTable::intern(fd.name(), CHECK);
 851         java_lang_invoke_MemberName::set_name(mname(), name());
 852       }
 853       if (!have_type) {
 854         Handle type = java_lang_String::create_from_symbol(fd.signature(), CHECK);
 855         java_lang_invoke_MemberName::set_type(mname(), type());
 856       }
 857       return;
 858     }
 859   }
 860   THROW_MSG(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format");
 861 }
 862 
 863 int MethodHandles::find_MemberNames(klassOop k,
 864                                     Symbol* name, Symbol* sig,
 865                                     int mflags, klassOop caller,
 866                                     int skip, objArrayOop results) {
 867   DEBUG_ONLY(No_Safepoint_Verifier nsv);
 868   // this code contains no safepoints!
 869 
 870   // %%% take caller into account!
 871 
 872   if (k == NULL || !Klass::cast(k)->oop_is_instance())  return -1;
 873 
 874   int rfill = 0, rlimit = results->length(), rskip = skip;
 875   // overflow measurement:
 876   int overflow = 0, overflow_limit = MAX2(1000, rlimit);
 877 
 878   int match_flags = mflags;
 879   bool search_superc = ((match_flags & SEARCH_SUPERCLASSES) != 0);
 880   bool search_intfc  = ((match_flags & SEARCH_INTERFACES)   != 0);
 881   bool local_only = !(search_superc | search_intfc);
 882   bool classes_only = false;
 883 
 884   if (name != NULL) {
 885     if (name->utf8_length() == 0)  return 0; // a match is not possible
 886   }
 887   if (sig != NULL) {
 888     if (sig->utf8_length() == 0)  return 0; // a match is not possible
 889     if (sig->byte_at(0) == '(')
 890       match_flags &= ~(IS_FIELD | IS_TYPE);
 891     else
 892       match_flags &= ~(IS_CONSTRUCTOR | IS_METHOD);
 893   }
 894 
 895   if ((match_flags & IS_TYPE) != 0) {
 896     // NYI, and Core Reflection works quite well for this query
 897   }
 898 
 899   if ((match_flags & IS_FIELD) != 0) {
 900     for (FieldStream st(k, local_only, !search_intfc); !st.eos(); st.next()) {
 901       if (name != NULL && st.name() != name)
 902           continue;
 903       if (sig != NULL && st.signature() != sig)
 904         continue;
 905       // passed the filters
 906       if (rskip > 0) {
 907         --rskip;
 908       } else if (rfill < rlimit) {
 909         oop result = results->obj_at(rfill++);
 910         if (!java_lang_invoke_MemberName::is_instance(result))
 911           return -99;  // caller bug!
 912         MethodHandles::init_MemberName(result, st.klass()->as_klassOop(), st.access_flags(), st.offset());
 913       } else if (++overflow >= overflow_limit) {
 914         match_flags = 0; break; // got tired of looking at overflow
 915       }
 916     }
 917   }
 918 
 919   if ((match_flags & (IS_METHOD | IS_CONSTRUCTOR)) != 0) {
 920     // watch out for these guys:
 921     Symbol* init_name   = vmSymbols::object_initializer_name();
 922     Symbol* clinit_name = vmSymbols::class_initializer_name();
 923     if (name == clinit_name)  clinit_name = NULL; // hack for exposing <clinit>
 924     bool negate_name_test = false;
 925     // fix name so that it captures the intention of IS_CONSTRUCTOR
 926     if (!(match_flags & IS_METHOD)) {
 927       // constructors only
 928       if (name == NULL) {
 929         name = init_name;
 930       } else if (name != init_name) {
 931         return 0;               // no constructors of this method name
 932       }
 933     } else if (!(match_flags & IS_CONSTRUCTOR)) {
 934       // methods only
 935       if (name == NULL) {
 936         name = init_name;
 937         negate_name_test = true; // if we see the name, we *omit* the entry
 938       } else if (name == init_name) {
 939         return 0;               // no methods of this constructor name
 940       }
 941     } else {
 942       // caller will accept either sort; no need to adjust name
 943     }
 944     for (MethodStream st(k, local_only, !search_intfc); !st.eos(); st.next()) {
 945       methodOop m = st.method();
 946       Symbol* m_name = m->name();
 947       if (m_name == clinit_name)
 948         continue;
 949       if (name != NULL && ((m_name != name) ^ negate_name_test))
 950           continue;
 951       if (sig != NULL && m->signature() != sig)
 952         continue;
 953       // passed the filters
 954       if (rskip > 0) {
 955         --rskip;
 956       } else if (rfill < rlimit) {
 957         oop result = results->obj_at(rfill++);
 958         if (!java_lang_invoke_MemberName::is_instance(result))
 959           return -99;  // caller bug!
 960         MethodHandles::init_MemberName(result, m, true);
 961       } else if (++overflow >= overflow_limit) {
 962         match_flags = 0; break; // got tired of looking at overflow
 963       }
 964     }
 965   }
 966 
 967   // return number of elements we at leasted wanted to initialize
 968   return rfill + overflow;
 969 }
 970 
 971 
 972 // Decode this java.lang.Class object into an instanceKlass, if possible.
 973 // Throw IAE if not
 974 instanceKlassHandle MethodHandles::resolve_instance_klass(oop java_mirror_oop, TRAPS) {
 975   instanceKlassHandle empty;
 976   klassOop caller = NULL;
 977   if (java_lang_Class::is_instance(java_mirror_oop)) {
 978     caller = java_lang_Class::as_klassOop(java_mirror_oop);
 979   }
 980   if (caller == NULL || !Klass::cast(caller)->oop_is_instance()) {
 981     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(), "not a class", empty);
 982   }
 983   return instanceKlassHandle(THREAD, caller);
 984 }
 985 
 986 
 987 
 988 // Decode the vmtarget field of a method handle.
 989 // Sanitize out methodOops, klassOops, and any other non-Java data.
 990 // This is for debugging and reflection.
 991 oop MethodHandles::encode_target(Handle mh, int format, TRAPS) {
 992   assert(java_lang_invoke_MethodHandle::is_instance(mh()), "must be a MH");
 993   if (format == ETF_FORCE_DIRECT_HANDLE ||
 994       format == ETF_COMPILE_DIRECT_HANDLE) {
 995     // Internal function for stress testing.
 996     Handle mt = java_lang_invoke_MethodHandle::type(mh());
 997     int invocation_count = 10000;
 998     TempNewSymbol signature = java_lang_invoke_MethodType::as_signature(mt(), true, CHECK_NULL);
 999     bool omit_receiver_argument = true;
1000     MethodHandleCompiler mhc(mh, vmSymbols::invoke_name(), signature, invocation_count, omit_receiver_argument, CHECK_NULL);
1001     methodHandle m = mhc.compile(CHECK_NULL);
1002     if (StressMethodHandleWalk && Verbose || PrintMiscellaneous) {
1003       tty->print_cr("MethodHandleNatives.getTarget(%s)",
1004                     format == ETF_FORCE_DIRECT_HANDLE ? "FORCE_DIRECT" : "COMPILE_DIRECT");
1005       if (Verbose) {
1006         m->print_codes();
1007       }
1008     }
1009     if (StressMethodHandleWalk) {
1010       InterpreterOopMap mask;
1011       OopMapCache::compute_one_oop_map(m, m->code_size() - 1, &mask);
1012     }
1013     if ((format == ETF_COMPILE_DIRECT_HANDLE ||
1014          CompilationPolicy::must_be_compiled(m))
1015         && !instanceKlass::cast(m->method_holder())->is_not_initialized()
1016         && CompilationPolicy::can_be_compiled(m)) {
1017       // Force compilation
1018       CompileBroker::compile_method(m, InvocationEntryBci,
1019                                     CompilationPolicy::policy()->initial_compile_level(),
1020                                     methodHandle(), 0, "MethodHandleNatives.getTarget",
1021                                     CHECK_NULL);
1022     }
1023     // Now wrap m in a DirectMethodHandle.
1024     instanceKlassHandle dmh_klass(THREAD, SystemDictionary::DirectMethodHandle_klass());
1025     Handle dmh = dmh_klass->allocate_instance_handle(CHECK_NULL);
1026     JavaValue ignore_result(T_VOID);
1027     Symbol* init_name = vmSymbols::object_initializer_name();
1028     Symbol* init_sig  = vmSymbols::notifyGenericMethodType_signature();
1029     JavaCalls::call_special(&ignore_result, dmh,
1030                             SystemDictionaryHandles::MethodHandle_klass(), init_name, init_sig,
1031                             java_lang_invoke_MethodHandle::type(mh()), CHECK_NULL);
1032     MethodHandles::init_DirectMethodHandle(dmh, m, false, CHECK_NULL);
1033     return dmh();
1034   }
1035   if (format == ETF_HANDLE_OR_METHOD_NAME) {
1036     oop target = java_lang_invoke_MethodHandle::vmtarget(mh());
1037     if (target == NULL) {
1038       return NULL;                // unformed MH
1039     }
1040     klassOop tklass = target->klass();
1041     if (Klass::cast(tklass)->is_subclass_of(SystemDictionary::Object_klass())) {
1042       return target;              // target is another MH (or something else?)
1043     }
1044   }
1045   if (format == ETF_DIRECT_HANDLE) {
1046     oop target = mh();
1047     for (;;) {
1048       if (target->klass() == SystemDictionary::DirectMethodHandle_klass()) {
1049         return target;
1050       }
1051       if (!java_lang_invoke_MethodHandle::is_instance(target)){
1052         return NULL;                // unformed MH
1053       }
1054       target = java_lang_invoke_MethodHandle::vmtarget(target);
1055     }
1056   }
1057   // cases of metadata in MH.vmtarget:
1058   // - AMH can have methodOop for static invoke with bound receiver
1059   // - DMH can have methodOop for static invoke (on variable receiver)
1060   // - DMH can have klassOop for dispatched (non-static) invoke
1061   KlassHandle receiver_limit; int decode_flags = 0;
1062   methodHandle m = decode_MethodHandle(mh(), receiver_limit, decode_flags);
1063   if (m.is_null())  return NULL;
1064   switch (format) {
1065   case ETF_REFLECT_METHOD:
1066     // same as jni_ToReflectedMethod:
1067     if (m->is_initializer()) {
1068       return Reflection::new_constructor(m, THREAD);
1069     } else {
1070       return Reflection::new_method(m, UseNewReflection, false, THREAD);
1071     }
1072 
1073   case ETF_HANDLE_OR_METHOD_NAME:   // method, not handle
1074   case ETF_METHOD_NAME:
1075     {
1076       if (SystemDictionary::MemberName_klass() == NULL)  break;
1077       instanceKlassHandle mname_klass(THREAD, SystemDictionary::MemberName_klass());
1078       mname_klass->initialize(CHECK_NULL);
1079       Handle mname = mname_klass->allocate_instance_handle(CHECK_NULL);  // possible safepoint
1080       java_lang_invoke_MemberName::set_vmindex(mname(), VM_INDEX_UNINITIALIZED);
1081       bool do_dispatch = ((decode_flags & MethodHandles::_dmf_does_dispatch) != 0);
1082       init_MemberName(mname(), m(), do_dispatch);
1083       expand_MemberName(mname, 0, CHECK_NULL);
1084       return mname();
1085     }
1086   }
1087 
1088   // Unknown format code.
1089   char msg[50];
1090   jio_snprintf(msg, sizeof(msg), "unknown getTarget format=%d", format);
1091   THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), msg);
1092 }
1093 
1094 static const char* always_null_names[] = {
1095   "java/lang/Void",
1096   "java/lang/Null",
1097   //"java/lang/Nothing",
1098   "sun/dyn/empty/Empty",
1099   "sun/invoke/empty/Empty",
1100   NULL
1101 };
1102 
1103 static bool is_always_null_type(klassOop klass) {
1104   if (klass == NULL)  return false;  // safety
1105   if (!Klass::cast(klass)->oop_is_instance())  return false;
1106   instanceKlass* ik = instanceKlass::cast(klass);
1107   // Must be on the boot class path:
1108   if (ik->class_loader() != NULL)  return false;
1109   // Check the name.
1110   Symbol* name = ik->name();
1111   for (int i = 0; ; i++) {
1112     const char* test_name = always_null_names[i];
1113     if (test_name == NULL)  break;
1114     if (name->equals(test_name))
1115       return true;
1116   }
1117   return false;
1118 }
1119 
1120 bool MethodHandles::class_cast_needed(klassOop src, klassOop dst) {
1121   if (dst == NULL)  return true;
1122   if (src == NULL)  return (dst != SystemDictionary::Object_klass());
1123   if (src == dst || dst == SystemDictionary::Object_klass())
1124     return false;                               // quickest checks
1125   Klass* srck = Klass::cast(src);
1126   Klass* dstk = Klass::cast(dst);
1127   if (dstk->is_interface()) {
1128     // interface receivers can safely be viewed as untyped,
1129     // because interface calls always include a dynamic check
1130     //dstk = Klass::cast(SystemDictionary::Object_klass());
1131     return false;
1132   }
1133   if (srck->is_interface()) {
1134     // interface arguments must be viewed as untyped
1135     //srck = Klass::cast(SystemDictionary::Object_klass());
1136     return true;
1137   }
1138   if (is_always_null_type(src)) {
1139     // some source types are known to be never instantiated;
1140     // they represent references which are always null
1141     // such null references never fail to convert safely
1142     return false;
1143   }
1144   return !srck->is_subclass_of(dstk->as_klassOop());
1145 }
1146 
1147 static oop object_java_mirror() {
1148   return Klass::cast(SystemDictionary::Object_klass())->java_mirror();
1149 }
1150 
1151 bool MethodHandles::is_float_fixed_reinterpretation_cast(BasicType src, BasicType dst) {
1152   if (src == T_FLOAT)   return dst == T_INT;
1153   if (src == T_INT)     return dst == T_FLOAT;
1154   if (src == T_DOUBLE)  return dst == T_LONG;
1155   if (src == T_LONG)    return dst == T_DOUBLE;
1156   return false;
1157 }
1158 
1159 bool MethodHandles::same_basic_type_for_arguments(BasicType src,
1160                                                   BasicType dst,
1161                                                   bool raw,
1162                                                   bool for_return) {
1163   if (for_return) {
1164     // return values can always be forgotten:
1165     if (dst == T_VOID)  return true;
1166     if (src == T_VOID)  return raw && (dst == T_INT);
1167     // We allow caller to receive a garbage int, which is harmless.
1168     // This trick is pulled by trusted code (see VerifyType.canPassRaw).
1169   }
1170   assert(src != T_VOID && dst != T_VOID, "should not be here");
1171   if (src == dst)  return true;
1172   if (type2size[src] != type2size[dst])  return false;
1173   if (src == T_OBJECT || dst == T_OBJECT)  return false;
1174   if (raw)  return true;  // bitwise reinterpretation; caller guarantees safety
1175   // allow reinterpretation casts for integral widening
1176   if (is_subword_type(src)) { // subwords can fit in int or other subwords
1177     if (dst == T_INT)         // any subword fits in an int
1178       return true;
1179     if (src == T_BOOLEAN)     // boolean fits in any subword
1180       return is_subword_type(dst);
1181     if (src == T_BYTE && dst == T_SHORT)
1182       return true;            // remaining case: byte fits in short
1183   }
1184   // allow float/fixed reinterpretation casts
1185   if (is_float_fixed_reinterpretation_cast(src, dst))
1186     return true;
1187   return false;
1188 }
1189 
1190 const char* MethodHandles::check_method_receiver(methodOop m,
1191                                                  klassOop passed_recv_type) {
1192   assert(!m->is_static(), "caller resp.");
1193   if (passed_recv_type == NULL)
1194     return "receiver type is primitive";
1195   if (class_cast_needed(passed_recv_type, m->method_holder())) {
1196     Klass* formal = Klass::cast(m->method_holder());
1197     return SharedRuntime::generate_class_cast_message("receiver type",
1198                                                       formal->external_name());
1199   }
1200   return NULL;                  // checks passed
1201 }
1202 
1203 // Verify that m's signature can be called type-safely by a method handle
1204 // of the given method type 'mtype'.
1205 // It takes a TRAPS argument because it must perform symbol lookups.
1206 void MethodHandles::verify_method_signature(methodHandle m,
1207                                             Handle mtype,
1208                                             int first_ptype_pos,
1209                                             KlassHandle insert_ptype,
1210                                             TRAPS) {
1211   Handle mhi_type;
1212   if (m->is_method_handle_invoke()) {
1213     // use this more exact typing instead of the symbolic signature:
1214     mhi_type = Handle(THREAD, m->method_handle_type());
1215   }
1216   objArrayHandle ptypes(THREAD, java_lang_invoke_MethodType::ptypes(mtype()));
1217   int pnum = first_ptype_pos;
1218   int pmax = ptypes->length();
1219   int anum = 0;                 // method argument
1220   const char* err = NULL;
1221   ResourceMark rm(THREAD);
1222   for (SignatureStream ss(m->signature()); !ss.is_done(); ss.next()) {
1223     oop ptype_oop = NULL;
1224     if (ss.at_return_type()) {
1225       if (pnum != pmax)
1226         { err = "too many arguments"; break; }
1227       ptype_oop = java_lang_invoke_MethodType::rtype(mtype());
1228     } else {
1229       if (pnum >= pmax)
1230         { err = "not enough arguments"; break; }
1231       if (pnum >= 0)
1232         ptype_oop = ptypes->obj_at(pnum);
1233       else if (insert_ptype.is_null())
1234         ptype_oop = NULL;
1235       else
1236         ptype_oop = insert_ptype->java_mirror();
1237       pnum += 1;
1238       anum += 1;
1239     }
1240     KlassHandle pklass;
1241     BasicType   ptype = T_OBJECT;
1242     bool   have_ptype = false;
1243     // missing ptype_oop does not match any non-reference; use Object to report the error
1244     pklass = SystemDictionaryHandles::Object_klass();
1245     if (ptype_oop != NULL) {
1246       have_ptype = true;
1247       klassOop pklass_oop = NULL;
1248       ptype = java_lang_Class::as_BasicType(ptype_oop, &pklass_oop);
1249       pklass = KlassHandle(THREAD, pklass_oop);
1250     }
1251     ptype_oop = NULL; //done with this
1252     KlassHandle aklass;
1253     BasicType   atype = ss.type();
1254     if (atype == T_ARRAY)  atype = T_OBJECT; // fold all refs to T_OBJECT
1255     if (atype == T_OBJECT) {
1256       if (!have_ptype) {
1257         // null matches any reference
1258         continue;
1259       }
1260       if (mhi_type.is_null()) {
1261         // If we fail to resolve types at this point, we will usually throw an error.
1262         TempNewSymbol name = ss.as_symbol_or_null();
1263         if (name != NULL) {
1264           instanceKlass* mk = instanceKlass::cast(m->method_holder());
1265           Handle loader(THREAD, mk->class_loader());
1266           Handle domain(THREAD, mk->protection_domain());
1267           klassOop aklass_oop = SystemDictionary::resolve_or_null(name, loader, domain, CHECK);
1268           if (aklass_oop != NULL)
1269             aklass = KlassHandle(THREAD, aklass_oop);
1270           if (aklass.is_null() &&
1271               pklass.not_null() &&
1272               loader.is_null() &&
1273               pklass->name() == name)
1274             // accept name equivalence here, since that's the best we can do
1275             aklass = pklass;
1276         }
1277       } else {
1278         // for method handle invokers we don't look at the name in the signature
1279         oop atype_oop;
1280         if (ss.at_return_type())
1281           atype_oop = java_lang_invoke_MethodType::rtype(mhi_type());
1282         else
1283           atype_oop = java_lang_invoke_MethodType::ptype(mhi_type(), anum-1);
1284         klassOop aklass_oop = NULL;
1285         atype = java_lang_Class::as_BasicType(atype_oop, &aklass_oop);
1286         aklass = KlassHandle(THREAD, aklass_oop);
1287       }
1288     }
1289     if (!ss.at_return_type()) {
1290       err = check_argument_type_change(ptype, pklass(), atype, aklass(), anum);
1291     } else {
1292       err = check_return_type_change(atype, aklass(), ptype, pklass()); // note reversal!
1293     }
1294     if (err != NULL)  break;
1295   }
1296 
1297   if (err != NULL) {
1298 #ifndef PRODUCT
1299     if (PrintMiscellaneous && (Verbose || WizardMode)) {
1300       tty->print("*** verify_method_signature failed: ");
1301       java_lang_invoke_MethodType::print_signature(mtype(), tty);
1302       tty->cr();
1303       tty->print_cr("    first_ptype_pos = %d, insert_ptype = "UINTX_FORMAT, first_ptype_pos, insert_ptype());
1304       tty->print("    Failing method: ");
1305       m->print();
1306     }
1307 #endif //PRODUCT
1308     THROW_MSG(vmSymbols::java_lang_InternalError(), err);
1309   }
1310 }
1311 
1312 // Main routine for verifying the MethodHandle.type of a proposed
1313 // direct or bound-direct method handle.
1314 void MethodHandles::verify_method_type(methodHandle m,
1315                                        Handle mtype,
1316                                        bool has_bound_recv,
1317                                        KlassHandle bound_recv_type,
1318                                        TRAPS) {
1319   bool m_needs_receiver = !m->is_static();
1320 
1321   const char* err = NULL;
1322 
1323   int first_ptype_pos = m_needs_receiver ? 1 : 0;
1324   if (has_bound_recv) {
1325     first_ptype_pos -= 1;  // ptypes do not include the bound argument; start earlier in them
1326     if (m_needs_receiver && bound_recv_type.is_null())
1327       { err = "bound receiver is not an object"; goto die; }
1328   }
1329 
1330   if (m_needs_receiver && err == NULL) {
1331     objArrayOop ptypes = java_lang_invoke_MethodType::ptypes(mtype());
1332     if (ptypes->length() < first_ptype_pos)
1333       { err = "receiver argument is missing"; goto die; }
1334     if (has_bound_recv)
1335       err = check_method_receiver(m(), bound_recv_type->as_klassOop());
1336     else
1337       err = check_method_receiver(m(), java_lang_Class::as_klassOop(ptypes->obj_at(first_ptype_pos-1)));
1338     if (err != NULL)  goto die;
1339   }
1340 
1341   // Check the other arguments for mistypes.
1342   verify_method_signature(m, mtype, first_ptype_pos, bound_recv_type, CHECK);
1343   return;
1344 
1345  die:
1346   THROW_MSG(vmSymbols::java_lang_InternalError(), err);
1347 }
1348 
1349 void MethodHandles::verify_vmslots(Handle mh, TRAPS) {
1350   // Verify vmslots.
1351   int check_slots = argument_slot_count(java_lang_invoke_MethodHandle::type(mh()));
1352   if (java_lang_invoke_MethodHandle::vmslots(mh()) != check_slots) {
1353     THROW_MSG(vmSymbols::java_lang_InternalError(), "bad vmslots in BMH");
1354   }
1355 }
1356 
1357 void MethodHandles::verify_vmargslot(Handle mh, int argnum, int argslot, TRAPS) {
1358   // Verify that argslot points at the given argnum.
1359   int check_slot = argument_slot(java_lang_invoke_MethodHandle::type(mh()), argnum);
1360   if (argslot != check_slot || argslot < 0) {
1361     ResourceMark rm;
1362     const char* fmt = "for argnum of %d, vmargslot is %d, should be %d";
1363     size_t msglen = strlen(fmt) + 3*11 + 1;
1364     char* msg = NEW_RESOURCE_ARRAY(char, msglen);
1365     jio_snprintf(msg, msglen, fmt, argnum, argslot, check_slot);
1366     THROW_MSG(vmSymbols::java_lang_InternalError(), msg);
1367   }
1368 }
1369 
1370 // Verify the correspondence between two method types.
1371 // Apart from the advertised changes, caller method type X must
1372 // be able to invoke the callee method Y type with no violations
1373 // of type integrity.
1374 // Return NULL if all is well, else a short error message.
1375 const char* MethodHandles::check_method_type_change(oop src_mtype, int src_beg, int src_end,
1376                                                     int insert_argnum, oop insert_type,
1377                                                     int change_argnum, oop change_type,
1378                                                     int delete_argnum,
1379                                                     oop dst_mtype, int dst_beg, int dst_end,
1380                                                     bool raw) {
1381   objArrayOop src_ptypes = java_lang_invoke_MethodType::ptypes(src_mtype);
1382   objArrayOop dst_ptypes = java_lang_invoke_MethodType::ptypes(dst_mtype);
1383 
1384   int src_max = src_ptypes->length();
1385   int dst_max = dst_ptypes->length();
1386 
1387   if (src_end == -1)  src_end = src_max;
1388   if (dst_end == -1)  dst_end = dst_max;
1389 
1390   assert(0 <= src_beg && src_beg <= src_end && src_end <= src_max, "oob");
1391   assert(0 <= dst_beg && dst_beg <= dst_end && dst_end <= dst_max, "oob");
1392 
1393   // pending actions; set to -1 when done:
1394   int ins_idx = insert_argnum, chg_idx = change_argnum, del_idx = delete_argnum;
1395 
1396   const char* err = NULL;
1397 
1398   // Walk along each array of parameter types, including a virtual
1399   // NULL end marker at the end of each.
1400   for (int src_idx = src_beg, dst_idx = dst_beg;
1401        (src_idx <= src_end && dst_idx <= dst_end);
1402        src_idx++, dst_idx++) {
1403     oop src_type = (src_idx == src_end) ? oop(NULL) : src_ptypes->obj_at(src_idx);
1404     oop dst_type = (dst_idx == dst_end) ? oop(NULL) : dst_ptypes->obj_at(dst_idx);
1405     bool fix_null_src_type = false;
1406 
1407     // Perform requested edits.
1408     if (ins_idx == src_idx) {
1409       // note that the inserted guy is never affected by a change or deletion
1410       ins_idx = -1;
1411       src_type = insert_type;
1412       fix_null_src_type = true;
1413       --src_idx;                // back up to process src type on next loop
1414       src_idx = src_end;
1415     } else {
1416       // note that the changed guy can be immediately deleted
1417       if (chg_idx == src_idx) {
1418         chg_idx = -1;
1419         assert(src_idx < src_end, "oob");
1420         src_type = change_type;
1421         fix_null_src_type = true;
1422       }
1423       if (del_idx == src_idx) {
1424         del_idx = -1;
1425         assert(src_idx < src_end, "oob");
1426         --dst_idx;
1427         continue;               // rerun loop after skipping this position
1428       }
1429     }
1430 
1431     if (src_type == NULL && fix_null_src_type)
1432       // explicit null in this case matches any dest reference
1433       src_type = (java_lang_Class::is_primitive(dst_type) ? object_java_mirror() : dst_type);
1434 
1435     // Compare the two argument types.
1436     if (src_type != dst_type) {
1437       if (src_type == NULL)  return "not enough arguments";
1438       if (dst_type == NULL)  return "too many arguments";
1439       err = check_argument_type_change(src_type, dst_type, dst_idx, raw);
1440       if (err != NULL)  return err;
1441     }
1442   }
1443 
1444   // Now compare return types also.
1445   oop src_rtype = java_lang_invoke_MethodType::rtype(src_mtype);
1446   oop dst_rtype = java_lang_invoke_MethodType::rtype(dst_mtype);
1447   if (src_rtype != dst_rtype) {
1448     err = check_return_type_change(dst_rtype, src_rtype, raw); // note reversal!
1449     if (err != NULL)  return err;
1450   }
1451 
1452   assert(err == NULL, "");
1453   return NULL;  // all is well
1454 }
1455 
1456 
1457 const char* MethodHandles::check_argument_type_change(BasicType src_type,
1458                                                       klassOop src_klass,
1459                                                       BasicType dst_type,
1460                                                       klassOop dst_klass,
1461                                                       int argnum,
1462                                                       bool raw) {
1463   const char* err = NULL;
1464   const bool for_return = (argnum < 0);
1465 
1466   // just in case:
1467   if (src_type == T_ARRAY)  src_type = T_OBJECT;
1468   if (dst_type == T_ARRAY)  dst_type = T_OBJECT;
1469 
1470   // Produce some nice messages if VerifyMethodHandles is turned on:
1471   if (!same_basic_type_for_arguments(src_type, dst_type, raw, for_return)) {
1472     if (src_type == T_OBJECT) {
1473       if (raw && is_java_primitive(dst_type))
1474         return NULL;    // ref-to-prim discards ref and returns zero
1475       err = (!for_return
1476              ? "type mismatch: passing a %s for method argument #%d, which expects primitive %s"
1477              : "type mismatch: returning a %s, but caller expects primitive %s");
1478     } else if (dst_type == T_OBJECT) {
1479       err = (!for_return
1480              ? "type mismatch: passing a primitive %s for method argument #%d, which expects %s"
1481              : "type mismatch: returning a primitive %s, but caller expects %s");
1482     } else {
1483       err = (!for_return
1484              ? "type mismatch: passing a %s for method argument #%d, which expects %s"
1485              : "type mismatch: returning a %s, but caller expects %s");
1486     }
1487   } else if (src_type == T_OBJECT && dst_type == T_OBJECT &&
1488              class_cast_needed(src_klass, dst_klass)) {
1489     if (!class_cast_needed(dst_klass, src_klass)) {
1490       if (raw)
1491         return NULL;    // reverse cast is OK; the MH target is trusted to enforce it
1492       err = (!for_return
1493              ? "cast required: passing a %s for method argument #%d, which expects %s"
1494              : "cast required: returning a %s, but caller expects %s");
1495     } else {
1496       err = (!for_return
1497              ? "reference mismatch: passing a %s for method argument #%d, which expects %s"
1498              : "reference mismatch: returning a %s, but caller expects %s");
1499     }
1500   } else {
1501     // passed the obstacle course
1502     return NULL;
1503   }
1504 
1505   // format, format, format
1506   const char* src_name = type2name(src_type);
1507   const char* dst_name = type2name(dst_type);
1508   if (src_name == NULL)  src_name = "unknown type";
1509   if (dst_name == NULL)  dst_name = "unknown type";
1510   if (src_type == T_OBJECT)
1511     src_name = (src_klass != NULL) ? Klass::cast(src_klass)->external_name() : "an unresolved class";
1512   if (dst_type == T_OBJECT)
1513     dst_name = (dst_klass != NULL) ? Klass::cast(dst_klass)->external_name() : "an unresolved class";
1514 
1515   size_t msglen = strlen(err) + strlen(src_name) + strlen(dst_name) + (argnum < 10 ? 1 : 11);
1516   char* msg = NEW_RESOURCE_ARRAY(char, msglen + 1);
1517   if (!for_return) {
1518     assert(strstr(err, "%d") != NULL, "");
1519     jio_snprintf(msg, msglen, err, src_name, argnum, dst_name);
1520   } else {
1521     assert(strstr(err, "%d") == NULL, "");
1522     jio_snprintf(msg, msglen, err, src_name,         dst_name);
1523   }
1524   return msg;
1525 }
1526 
1527 // Compute the depth within the stack of the given argument, i.e.,
1528 // the combined size of arguments to the right of the given argument.
1529 // For the last argument (ptypes.length-1) this will be zero.
1530 // For the first argument (0) this will be the size of all
1531 // arguments but that one.  For the special number -1, this
1532 // will be the size of all arguments, including the first.
1533 // If the argument is neither -1 nor a valid argument index,
1534 // then return a negative number.  Otherwise, the result
1535 // is in the range [0..vmslots] inclusive.
1536 int MethodHandles::argument_slot(oop method_type, int arg) {
1537   objArrayOop ptypes = java_lang_invoke_MethodType::ptypes(method_type);
1538   int argslot = 0;
1539   int len = ptypes->length();
1540   if (arg < -1 || arg >= len)  return -99;
1541   for (int i = len-1; i > arg; i--) {
1542     BasicType bt = java_lang_Class::as_BasicType(ptypes->obj_at(i));
1543     argslot += type2size[bt];
1544   }
1545   assert(argument_slot_to_argnum(method_type, argslot) == arg, "inverse works");
1546   return argslot;
1547 }
1548 
1549 // Given a slot number, return the argument number.
1550 int MethodHandles::argument_slot_to_argnum(oop method_type, int query_argslot) {
1551   objArrayOop ptypes = java_lang_invoke_MethodType::ptypes(method_type);
1552   int argslot = 0;
1553   int len = ptypes->length();
1554   for (int i = len-1; i >= 0; i--) {
1555     if (query_argslot == argslot)  return i;
1556     BasicType bt = java_lang_Class::as_BasicType(ptypes->obj_at(i));
1557     argslot += type2size[bt];
1558   }
1559   // return pseudo-arg deepest in stack:
1560   if (query_argslot == argslot)  return -1;
1561   return -99;                   // oob slot, or splitting a double-slot arg
1562 }
1563 
1564 methodHandle MethodHandles::dispatch_decoded_method(methodHandle m,
1565                                                     KlassHandle receiver_limit,
1566                                                     int decode_flags,
1567                                                     KlassHandle receiver_klass,
1568                                                     TRAPS) {
1569   assert((decode_flags & ~_DMF_DIRECT_MASK) == 0, "must be direct method reference");
1570   assert((decode_flags & _dmf_has_receiver) != 0, "must have a receiver or first reference argument");
1571 
1572   if (!m->is_static() &&
1573       (receiver_klass.is_null() || !receiver_klass->is_subtype_of(m->method_holder())))
1574     // given type does not match class of method, or receiver is null!
1575     // caller should have checked this, but let's be extra careful...
1576     return methodHandle();
1577 
1578   if (receiver_limit.not_null() &&
1579       (receiver_klass.not_null() && !receiver_klass->is_subtype_of(receiver_limit())))
1580     // given type is not limited to the receiver type
1581     // note that a null receiver can match any reference value, for a static method
1582     return methodHandle();
1583 
1584   if (!(decode_flags & MethodHandles::_dmf_does_dispatch)) {
1585     // pre-dispatched or static method (null receiver is OK for static)
1586     return m;
1587 
1588   } else if (receiver_klass.is_null()) {
1589     // null receiver value; cannot dispatch
1590     return methodHandle();
1591 
1592   } else if (!(decode_flags & MethodHandles::_dmf_from_interface)) {
1593     // perform virtual dispatch
1594     int vtable_index = m->vtable_index();
1595     guarantee(vtable_index >= 0, "valid vtable index");
1596 
1597     // receiver_klass might be an arrayKlassOop but all vtables start at
1598     // the same place. The cast is to avoid virtual call and assertion.
1599     // See also LinkResolver::runtime_resolve_virtual_method.
1600     instanceKlass* inst = (instanceKlass*)Klass::cast(receiver_klass());
1601     DEBUG_ONLY(inst->verify_vtable_index(vtable_index));
1602     methodOop m_oop = inst->method_at_vtable(vtable_index);
1603     return methodHandle(THREAD, m_oop);
1604 
1605   } else {
1606     // perform interface dispatch
1607     int itable_index = klassItable::compute_itable_index(m());
1608     guarantee(itable_index >= 0, "valid itable index");
1609     instanceKlass* inst = instanceKlass::cast(receiver_klass());
1610     methodOop m_oop = inst->method_at_itable(m->method_holder(), itable_index, THREAD);
1611     return methodHandle(THREAD, m_oop);
1612   }
1613 }
1614 
1615 void MethodHandles::verify_DirectMethodHandle(Handle mh, methodHandle m, TRAPS) {
1616   // Verify type.
1617   Handle mtype(THREAD, java_lang_invoke_MethodHandle::type(mh()));
1618   verify_method_type(m, mtype, false, KlassHandle(), CHECK);
1619 
1620   // Verify vmslots.
1621   if (java_lang_invoke_MethodHandle::vmslots(mh()) != m->size_of_parameters()) {
1622     THROW_MSG(vmSymbols::java_lang_InternalError(), "bad vmslots in DMH");
1623   }
1624 }
1625 
1626 void MethodHandles::init_DirectMethodHandle(Handle mh, methodHandle m, bool do_dispatch, TRAPS) {
1627   // Check arguments.
1628   if (mh.is_null() || m.is_null() ||
1629       (!do_dispatch && m->is_abstract())) {
1630     THROW(vmSymbols::java_lang_InternalError());
1631   }
1632 
1633   java_lang_invoke_MethodHandle::init_vmslots(mh());
1634 
1635   if (VerifyMethodHandles) {
1636     // The privileged code which invokes this routine should not make
1637     // a mistake about types, but it's better to verify.
1638     verify_DirectMethodHandle(mh, m, CHECK);
1639   }
1640 
1641   // Finally, after safety checks are done, link to the target method.
1642   // We will follow the same path as the latter part of
1643   // InterpreterRuntime::resolve_invoke(), which first finds the method
1644   // and then decides how to populate the constant pool cache entry
1645   // that links the interpreter calls to the method.  We need the same
1646   // bits, and will use the same calling sequence code.
1647 
1648   int    vmindex = methodOopDesc::garbage_vtable_index;
1649   Handle vmtarget;
1650 
1651   instanceKlass::cast(m->method_holder())->link_class(CHECK);
1652 
1653   MethodHandleEntry* me = NULL;
1654   if (do_dispatch && Klass::cast(m->method_holder())->is_interface()) {
1655     // We are simulating an invokeinterface instruction.
1656     // (We might also be simulating an invokevirtual on a miranda method,
1657     // but it is safe to treat it as an invokeinterface.)
1658     assert(!m->can_be_statically_bound(), "no final methods on interfaces");
1659     vmindex = klassItable::compute_itable_index(m());
1660     assert(vmindex >= 0, "(>=0) == do_dispatch");
1661     // Set up same bits as ConstantPoolCacheEntry::set_interface_call().
1662     vmtarget = m->method_holder(); // the interface
1663     me = MethodHandles::entry(MethodHandles::_invokeinterface_mh);
1664   } else if (!do_dispatch || m->can_be_statically_bound()) {
1665     // We are simulating an invokestatic or invokespecial instruction.
1666     // Set up the method pointer, just like ConstantPoolCacheEntry::set_method().
1667     vmtarget = m;
1668     // this does not help dispatch, but it will make it possible to parse this MH:
1669     vmindex  = methodOopDesc::nonvirtual_vtable_index;
1670     assert(vmindex < 0, "(>=0) == do_dispatch");
1671     if (!m->is_static()) {
1672       me = MethodHandles::entry(MethodHandles::_invokespecial_mh);
1673     } else {
1674       me = MethodHandles::entry(MethodHandles::_invokestatic_mh);
1675       // Part of the semantics of a static call is an initialization barrier.
1676       // For a DMH, it is done now, when the handle is created.
1677       Klass* k = Klass::cast(m->method_holder());
1678       if (k->should_be_initialized()) {
1679         k->initialize(CHECK);  // possible safepoint
1680       }
1681     }
1682   } else {
1683     // We are simulating an invokevirtual instruction.
1684     // Set up the vtable index, just like ConstantPoolCacheEntry::set_method().
1685     // The key logic is LinkResolver::runtime_resolve_virtual_method.
1686     vmindex  = m->vtable_index();
1687     vmtarget = m->method_holder();
1688     me = MethodHandles::entry(MethodHandles::_invokevirtual_mh);
1689   }
1690 
1691   if (me == NULL) { THROW(vmSymbols::java_lang_InternalError()); }
1692 
1693   java_lang_invoke_DirectMethodHandle::set_vmtarget(mh(), vmtarget());
1694   java_lang_invoke_DirectMethodHandle::set_vmindex( mh(), vmindex);
1695   DEBUG_ONLY(KlassHandle rlimit; int flags);
1696   assert(MethodHandles::decode_method(mh(), rlimit, flags) == m,
1697          "properly stored for later decoding");
1698   DEBUG_ONLY(bool actual_do_dispatch = ((flags & _dmf_does_dispatch) != 0));
1699   assert(!(actual_do_dispatch && !do_dispatch),
1700          "do not perform dispatch if !do_dispatch specified");
1701   assert(actual_do_dispatch == (vmindex >= 0), "proper later decoding of do_dispatch");
1702   assert(decode_MethodHandle_stack_pushes(mh()) == 0, "DMH does not move stack");
1703 
1704   // Done!
1705   java_lang_invoke_MethodHandle::set_vmentry(mh(), me);
1706 }
1707 
1708 void MethodHandles::verify_BoundMethodHandle_with_receiver(Handle mh,
1709                                                            methodHandle m,
1710                                                            TRAPS) {
1711   // Verify type.
1712   KlassHandle bound_recv_type;
1713   {
1714     oop receiver = java_lang_invoke_BoundMethodHandle::argument(mh());
1715     if (receiver != NULL)
1716       bound_recv_type = KlassHandle(THREAD, receiver->klass());
1717   }
1718   Handle mtype(THREAD, java_lang_invoke_MethodHandle::type(mh()));
1719   verify_method_type(m, mtype, true, bound_recv_type, CHECK);
1720 
1721   int receiver_pos = m->size_of_parameters() - 1;
1722 
1723   // Verify MH.vmargslot, which should point at the bound receiver.
1724   verify_vmargslot(mh, -1, java_lang_invoke_BoundMethodHandle::vmargslot(mh()), CHECK);
1725   //verify_vmslots(mh, CHECK);
1726 
1727   // Verify vmslots.
1728   if (java_lang_invoke_MethodHandle::vmslots(mh()) != receiver_pos) {
1729     THROW_MSG(vmSymbols::java_lang_InternalError(), "bad vmslots in BMH (receiver)");
1730   }
1731 }
1732 
1733 // Initialize a BMH with a receiver bound directly to a methodOop.
1734 void MethodHandles::init_BoundMethodHandle_with_receiver(Handle mh,
1735                                                          methodHandle original_m,
1736                                                          KlassHandle receiver_limit,
1737                                                          int decode_flags,
1738                                                          TRAPS) {
1739   // Check arguments.
1740   if (mh.is_null() || original_m.is_null()) {
1741     THROW(vmSymbols::java_lang_InternalError());
1742   }
1743 
1744   KlassHandle receiver_klass;
1745   {
1746     oop receiver_oop = java_lang_invoke_BoundMethodHandle::argument(mh());
1747     if (receiver_oop != NULL)
1748       receiver_klass = KlassHandle(THREAD, receiver_oop->klass());
1749   }
1750   methodHandle m = dispatch_decoded_method(original_m,
1751                                            receiver_limit, decode_flags,
1752                                            receiver_klass,
1753                                            CHECK);
1754   if (m.is_null())      { THROW(vmSymbols::java_lang_InternalError()); }
1755   if (m->is_abstract()) { THROW(vmSymbols::java_lang_AbstractMethodError()); }
1756 
1757   java_lang_invoke_MethodHandle::init_vmslots(mh());
1758   int vmargslot = m->size_of_parameters() - 1;
1759   assert(java_lang_invoke_BoundMethodHandle::vmargslot(mh()) == vmargslot, "");
1760 
1761   if (VerifyMethodHandles) {
1762     verify_BoundMethodHandle_with_receiver(mh, m, CHECK);
1763   }
1764 
1765   java_lang_invoke_BoundMethodHandle::set_vmtarget(mh(), m());
1766 
1767   DEBUG_ONLY(KlassHandle junk1; int junk2);
1768   assert(MethodHandles::decode_method(mh(), junk1, junk2) == m, "properly stored for later decoding");
1769   assert(decode_MethodHandle_stack_pushes(mh()) == 1, "BMH pushes one stack slot");
1770 
1771   // Done!
1772   java_lang_invoke_MethodHandle::set_vmentry(mh(), MethodHandles::entry(MethodHandles::_bound_ref_direct_mh));
1773 }
1774 
1775 void MethodHandles::verify_BoundMethodHandle(Handle mh, Handle target, int argnum,
1776                                              bool direct_to_method, TRAPS) {
1777   ResourceMark rm;
1778   Handle ptype_handle(THREAD,
1779                            java_lang_invoke_MethodType::ptype(java_lang_invoke_MethodHandle::type(target()), argnum));
1780   KlassHandle ptype_klass;
1781   BasicType ptype = java_lang_Class::as_BasicType(ptype_handle(), &ptype_klass);
1782   int slots_pushed = type2size[ptype];
1783 
1784   oop argument = java_lang_invoke_BoundMethodHandle::argument(mh());
1785 
1786   const char* err = NULL;
1787 
1788   switch (ptype) {
1789   case T_OBJECT:
1790     if (argument != NULL)
1791       // we must implicitly convert from the arg type to the outgoing ptype
1792       err = check_argument_type_change(T_OBJECT, argument->klass(), ptype, ptype_klass(), argnum);
1793     break;
1794 
1795   case T_ARRAY: case T_VOID:
1796     assert(false, "array, void do not appear here");
1797   default:
1798     if (ptype != T_INT && !is_subword_type(ptype)) {
1799       err = "unexpected parameter type";
1800       break;
1801     }
1802     // check subrange of Integer.value, if necessary
1803     if (argument == NULL || argument->klass() != SystemDictionary::Integer_klass()) {
1804       err = "bound integer argument must be of type java.lang.Integer";
1805       break;
1806     }
1807     if (ptype != T_INT) {
1808       int value_offset = java_lang_boxing_object::value_offset_in_bytes(T_INT);
1809       jint value = argument->int_field(value_offset);
1810       int vminfo = adapter_unbox_subword_vminfo(ptype);
1811       jint subword = truncate_subword_from_vminfo(value, vminfo);
1812       if (value != subword) {
1813         err = "bound subword value does not fit into the subword type";
1814         break;
1815       }
1816     }
1817     break;
1818   case T_FLOAT:
1819   case T_DOUBLE:
1820   case T_LONG:
1821     {
1822       // we must implicitly convert from the unboxed arg type to the outgoing ptype
1823       BasicType argbox = java_lang_boxing_object::basic_type(argument);
1824       if (argbox != ptype) {
1825         err = check_argument_type_change(T_OBJECT, (argument == NULL
1826                                                     ? SystemDictionary::Object_klass()
1827                                                     : argument->klass()),
1828                                          ptype, ptype_klass(), argnum);
1829         assert(err != NULL, "this must be an error");
1830       }
1831       break;
1832     }
1833   }
1834 
1835   if (err == NULL) {
1836     DEBUG_ONLY(int this_pushes = decode_MethodHandle_stack_pushes(mh()));
1837     if (direct_to_method) {
1838       assert(this_pushes == slots_pushed, "BMH pushes one or two stack slots");
1839     } else {
1840       int target_pushes = decode_MethodHandle_stack_pushes(target());
1841       assert(this_pushes == slots_pushed + target_pushes, "BMH stack motion must be correct");
1842     }
1843   }
1844 
1845   if (err == NULL) {
1846     // Verify the rest of the method type.
1847     err = check_method_type_insertion(java_lang_invoke_MethodHandle::type(mh()),
1848                                       argnum, ptype_handle(),
1849                                       java_lang_invoke_MethodHandle::type(target()));
1850   }
1851 
1852   if (err != NULL) {
1853     THROW_MSG(vmSymbols::java_lang_InternalError(), err);
1854   }
1855 }
1856 
1857 void MethodHandles::init_BoundMethodHandle(Handle mh, Handle target, int argnum, TRAPS) {
1858   // Check arguments.
1859   if (mh.is_null() || target.is_null() || !java_lang_invoke_MethodHandle::is_instance(target())) {
1860     THROW(vmSymbols::java_lang_InternalError());
1861   }
1862 
1863   java_lang_invoke_MethodHandle::init_vmslots(mh());
1864   int argslot = java_lang_invoke_BoundMethodHandle::vmargslot(mh());
1865 
1866   if (VerifyMethodHandles) {
1867     int insert_after = argnum - 1;
1868     verify_vmargslot(mh, insert_after, argslot, CHECK);
1869     verify_vmslots(mh, CHECK);
1870   }
1871 
1872   // Get bound type and required slots.
1873   BasicType ptype;
1874   {
1875     oop ptype_oop = java_lang_invoke_MethodType::ptype(java_lang_invoke_MethodHandle::type(target()), argnum);
1876     ptype = java_lang_Class::as_BasicType(ptype_oop);
1877   }
1878   int slots_pushed = type2size[ptype];
1879 
1880   // If (a) the target is a direct non-dispatched method handle,
1881   // or (b) the target is a dispatched direct method handle and we
1882   // are binding the receiver, cut out the middle-man.
1883   // Do this by decoding the DMH and using its methodOop directly as vmtarget.
1884   bool direct_to_method = false;
1885   if (OptimizeMethodHandles &&
1886       target->klass() == SystemDictionary::DirectMethodHandle_klass() &&
1887       (argnum != 0 || java_lang_invoke_BoundMethodHandle::argument(mh()) != NULL) &&
1888       (argnum == 0 || java_lang_invoke_DirectMethodHandle::vmindex(target()) < 0)) {
1889     KlassHandle receiver_limit; int decode_flags = 0;
1890     methodHandle m = decode_method(target(), receiver_limit, decode_flags);
1891     if (m.is_null()) { THROW_MSG(vmSymbols::java_lang_InternalError(), "DMH failed to decode"); }
1892     DEBUG_ONLY(int m_vmslots = m->size_of_parameters() - slots_pushed); // pos. of 1st arg.
1893     assert(java_lang_invoke_BoundMethodHandle::vmslots(mh()) == m_vmslots, "type w/ m sig");
1894     if (argnum == 0 && (decode_flags & _dmf_has_receiver) != 0) {
1895       init_BoundMethodHandle_with_receiver(mh, m,
1896                                            receiver_limit, decode_flags,
1897                                            CHECK);
1898       return;
1899     }
1900 
1901     // Even if it is not a bound receiver, we still might be able
1902     // to bind another argument and still invoke the methodOop directly.
1903     if (!(decode_flags & _dmf_does_dispatch)) {
1904       direct_to_method = true;
1905       java_lang_invoke_BoundMethodHandle::set_vmtarget(mh(), m());
1906     }
1907   }
1908   if (!direct_to_method)
1909     java_lang_invoke_BoundMethodHandle::set_vmtarget(mh(), target());
1910 
1911   if (VerifyMethodHandles) {
1912     verify_BoundMethodHandle(mh, target, argnum, direct_to_method, CHECK);
1913   }
1914 
1915   // Next question:  Is this a ref, int, or long bound value?
1916   MethodHandleEntry* me = NULL;
1917   if (ptype == T_OBJECT) {
1918     if (direct_to_method)  me = MethodHandles::entry(_bound_ref_direct_mh);
1919     else                   me = MethodHandles::entry(_bound_ref_mh);
1920   } else if (slots_pushed == 2) {
1921     if (direct_to_method)  me = MethodHandles::entry(_bound_long_direct_mh);
1922     else                   me = MethodHandles::entry(_bound_long_mh);
1923   } else if (slots_pushed == 1) {
1924     if (direct_to_method)  me = MethodHandles::entry(_bound_int_direct_mh);
1925     else                   me = MethodHandles::entry(_bound_int_mh);
1926   } else {
1927     assert(false, "");
1928   }
1929 
1930   // Done!
1931   java_lang_invoke_MethodHandle::set_vmentry(mh(), me);
1932 }
1933 
1934 static void throw_InternalError_for_bad_conversion(int conversion, const char* err, TRAPS) {
1935   char msg[200];
1936   jio_snprintf(msg, sizeof(msg), "bad adapter (conversion=0x%08x): %s", conversion, err);
1937   THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), msg);
1938 }
1939 
1940 void MethodHandles::verify_AdapterMethodHandle(Handle mh, int argnum, TRAPS) {
1941   ResourceMark rm;
1942   jint conversion = java_lang_invoke_AdapterMethodHandle::conversion(mh());
1943   int  argslot    = java_lang_invoke_AdapterMethodHandle::vmargslot(mh());
1944 
1945   verify_vmargslot(mh, argnum, argslot, CHECK);
1946   verify_vmslots(mh, CHECK);
1947 
1948   jint conv_op    = adapter_conversion_op(conversion);
1949   if (!conv_op_valid(conv_op)) {
1950     throw_InternalError_for_bad_conversion(conversion, "unknown conversion op", THREAD);
1951     return;
1952   }
1953   EntryKind ek = adapter_entry_kind(conv_op);
1954 
1955   int stack_move = adapter_conversion_stack_move(conversion);
1956   BasicType src  = adapter_conversion_src_type(conversion);
1957   BasicType dest = adapter_conversion_dest_type(conversion);
1958   int vminfo     = adapter_conversion_vminfo(conversion); // should be zero
1959 
1960   Handle argument(THREAD,  java_lang_invoke_AdapterMethodHandle::argument(mh()));
1961   Handle target(THREAD,    java_lang_invoke_AdapterMethodHandle::vmtarget(mh()));
1962   Handle src_mtype(THREAD, java_lang_invoke_MethodHandle::type(mh()));
1963   Handle dst_mtype(THREAD, java_lang_invoke_MethodHandle::type(target()));
1964   Handle arg_mtype;
1965 
1966   const char* err = NULL;
1967 
1968   if (err == NULL) {
1969     // Check that the correct argument is supplied, but only if it is required.
1970     switch (ek) {
1971     case _adapter_check_cast:     // target type of cast
1972     case _adapter_ref_to_prim:    // wrapper type from which to unbox
1973     case _adapter_spread_args:    // array type to spread from
1974       if (!java_lang_Class::is_instance(argument())
1975           || java_lang_Class::is_primitive(argument()))
1976         { err = "adapter requires argument of type java.lang.Class"; break; }
1977       if (ek == _adapter_spread_args) {
1978         // Make sure it is a suitable collection type.  (Array, for now.)
1979         Klass* ak = Klass::cast(java_lang_Class::as_klassOop(argument()));
1980         if (!ak->oop_is_array())
1981           { err = "spread adapter requires argument representing an array class"; break; }
1982         BasicType et = arrayKlass::cast(ak->as_klassOop())->element_type();
1983         if (et != dest && stack_move <= 0)
1984           { err = "spread adapter requires array class argument of correct type"; break; }
1985       }
1986       break;
1987     case _adapter_prim_to_ref:    // boxer MH to use
1988     case _adapter_collect_args:   // method handle which collects the args
1989     case _adapter_fold_args:      // method handle which collects the args
1990       if (!UseRicochetFrames) {
1991         { err = "box/collect/fold operators are not supported"; break; }
1992       }
1993       if (!java_lang_invoke_MethodHandle::is_instance(argument()))
1994         { err = "MethodHandle adapter argument required"; break; }
1995       arg_mtype = Handle(THREAD, java_lang_invoke_MethodHandle::type(argument()));
1996       break;
1997     default:
1998       if (argument.not_null())
1999         { err = "adapter has spurious argument"; break; }
2000       break;
2001     }
2002   }
2003 
2004   if (err == NULL) {
2005     // Check that the src/dest types are supplied if needed.
2006     // Also check relevant parameter or return types.
2007     switch (ek) {
2008     case _adapter_check_cast:
2009       if (src != T_OBJECT || dest != T_OBJECT) {
2010         err = "adapter requires object src/dest conversion subfields";
2011       }
2012       break;
2013     case _adapter_prim_to_prim:
2014       if (!is_java_primitive(src) || !is_java_primitive(dest) || src == dest) {
2015         err = "adapter requires primitive src/dest conversion subfields"; break;
2016       }
2017       if ( (src == T_FLOAT || src == T_DOUBLE) && !(dest == T_FLOAT || dest == T_DOUBLE) ||
2018           !(src == T_FLOAT || src == T_DOUBLE) &&  (dest == T_FLOAT || dest == T_DOUBLE)) {
2019         err = "adapter cannot convert beween floating and fixed-point"; break;
2020       }
2021       break;
2022     case _adapter_ref_to_prim:
2023       if (src != T_OBJECT || !is_java_primitive(dest)
2024           || argument() != Klass::cast(SystemDictionary::box_klass(dest))->java_mirror()) {
2025         err = "adapter requires primitive dest conversion subfield"; break;
2026       }
2027       break;
2028     case _adapter_prim_to_ref:
2029       if (!is_java_primitive(src) || dest != T_OBJECT) {
2030         err = "adapter requires primitive src conversion subfield"; break;
2031       }
2032       break;
2033     case _adapter_swap_args:
2034       {
2035         if (!src || !dest) {
2036           err = "adapter requires src/dest conversion subfields for swap"; break;
2037         }
2038         int src_size  = type2size[src];
2039         if (src_size != type2size[dest]) {
2040           err = "adapter requires equal sizes for src/dest"; break;
2041         }
2042         int src_slot   = argslot;
2043         int dest_slot  = vminfo;
2044         int src_arg    = argnum;
2045         int dest_arg   = argument_slot_to_argnum(src_mtype(), dest_slot);
2046         verify_vmargslot(mh, dest_arg, dest_slot, CHECK);
2047         if (!(dest_slot >= src_slot + src_size) &&
2048             !(src_slot >= dest_slot + src_size)) {
2049           err = "source, destination slots must be distinct"; break;
2050         } else if (!(src_slot > dest_slot)) {
2051           err = "source of swap must be deeper in stack"; break;
2052         }
2053         err = check_argument_type_change(java_lang_invoke_MethodType::ptype(src_mtype(), dest_arg),
2054                                          java_lang_invoke_MethodType::ptype(dst_mtype(), src_arg),
2055                                          dest_arg);
2056         if (err == NULL)
2057           err = check_argument_type_change(java_lang_invoke_MethodType::ptype(src_mtype(), src_arg),
2058                                            java_lang_invoke_MethodType::ptype(dst_mtype(), dest_arg),
2059                                            src_arg);
2060         break;
2061       }
2062     case _adapter_rot_args:
2063       {
2064         if (!src || !dest) {
2065           err = "adapter requires src/dest conversion subfields for rotate"; break;
2066         }
2067         int src_slot   = argslot;
2068         int limit_raw  = vminfo;
2069         bool rot_down  = (src_slot < limit_raw);
2070         int limit_bias = (rot_down ? MethodHandles::OP_ROT_ARGS_DOWN_LIMIT_BIAS : 0);
2071         int limit_slot = limit_raw - limit_bias;
2072         int src_arg    = argnum;
2073         int limit_arg  = argument_slot_to_argnum(src_mtype(), limit_slot);
2074         verify_vmargslot(mh, limit_arg, limit_slot, CHECK);
2075         if (src_slot == limit_slot) {
2076           err = "source, destination slots must be distinct"; break;
2077         }
2078         if (!rot_down) {  // rotate slots up == shift arguments left
2079           // limit_slot is an inclusive lower limit
2080           assert((src_slot > limit_slot) && (src_arg < limit_arg), "");
2081           // rotate up: [limit_slot..src_slot-ss] --> [limit_slot+ss..src_slot]
2082           // that is:   [src_arg+1..limit_arg] --> [src_arg..limit_arg-1]
2083           for (int i = src_arg+1; i <= limit_arg && err == NULL; i++) {
2084             err = check_argument_type_change(java_lang_invoke_MethodType::ptype(src_mtype(), i),
2085                                              java_lang_invoke_MethodType::ptype(dst_mtype(), i-1),
2086                                              i);
2087           }
2088         } else { // rotate slots down == shfit arguments right
2089           // limit_slot is an exclusive upper limit
2090           assert((src_slot < limit_slot - limit_bias) && (src_arg > limit_arg + limit_bias), "");
2091           // rotate down: [src_slot+ss..limit_slot) --> [src_slot..limit_slot-ss)
2092           // that is:     (limit_arg..src_arg-1] --> (dst_arg+1..src_arg]
2093           for (int i = limit_arg+1; i <= src_arg-1 && err == NULL; i++) {
2094             err = check_argument_type_change(java_lang_invoke_MethodType::ptype(src_mtype(), i),
2095                                              java_lang_invoke_MethodType::ptype(dst_mtype(), i+1),
2096                                              i);
2097           }
2098         }
2099         if (err == NULL) {
2100           int dest_arg = (rot_down ? limit_arg+1 : limit_arg);
2101           err = check_argument_type_change(java_lang_invoke_MethodType::ptype(src_mtype(), src_arg),
2102                                            java_lang_invoke_MethodType::ptype(dst_mtype(), dest_arg),
2103                                            src_arg);
2104         }
2105       }
2106       break;
2107     case _adapter_spread_args:
2108     case _adapter_collect_args:
2109     case _adapter_fold_args:
2110       {
2111         bool is_spread = (ek == _adapter_spread_args);
2112         bool is_fold   = (ek == _adapter_fold_args);
2113         BasicType coll_type = is_spread ? src : dest;
2114         BasicType elem_type = is_spread ? dest : src;
2115         // coll_type is type of args in collected form (or T_VOID if none)
2116         // elem_type is common type of args in spread form (or T_VOID if missing or heterogeneous)
2117         if (coll_type == 0 || elem_type == 0) {
2118           err = "adapter requires src/dest subfields for spread or collect"; break;
2119         }
2120         if (is_spread && coll_type != T_OBJECT) {
2121           err = "spread adapter requires object type for argument bundle"; break;
2122         }
2123         Handle spread_mtype = (is_spread ? dst_mtype : src_mtype);
2124         int spread_slot = argslot;
2125         int spread_arg  = argnum;
2126         int slots_pushed = stack_move / stack_move_unit();
2127         int coll_slot_count = type2size[coll_type];
2128         int spread_slot_count = (is_spread ? slots_pushed : -slots_pushed) + coll_slot_count;
2129         if (is_fold)  spread_slot_count = argument_slot_count(arg_mtype());
2130         if (!is_spread) {
2131           int init_slots = argument_slot_count(src_mtype());
2132           int coll_slots = argument_slot_count(arg_mtype());
2133           if (spread_slot_count > init_slots ||
2134               spread_slot_count != coll_slots) {
2135             err = "collect adapter has inconsistent arg counts"; break;
2136           }
2137           int next_slots = argument_slot_count(dst_mtype());
2138           int unchanged_slots_in  = (init_slots - spread_slot_count);
2139           int unchanged_slots_out = (next_slots - coll_slot_count - (is_fold ? spread_slot_count : 0));
2140           if (unchanged_slots_in != unchanged_slots_out) {
2141             err = "collect adapter continuation has inconsistent arg counts"; break;
2142           }
2143         }
2144       }
2145       break;
2146     default:
2147       if (src != 0 || dest != 0) {
2148         err = "adapter has spurious src/dest conversion subfields"; break;
2149       }
2150       break;
2151     }
2152   }
2153 
2154   if (err == NULL) {
2155     // Check the stack_move subfield.
2156     // It must always report the net change in stack size, positive or negative.
2157     int slots_pushed = stack_move / stack_move_unit();
2158     switch (ek) {
2159     case _adapter_prim_to_prim:
2160     case _adapter_ref_to_prim:
2161     case _adapter_prim_to_ref:
2162       if (slots_pushed != type2size[dest] - type2size[src]) {
2163         err = "wrong stack motion for primitive conversion";
2164       }
2165       break;
2166     case _adapter_dup_args:
2167       if (slots_pushed <= 0) {
2168         err = "adapter requires conversion subfield slots_pushed > 0";
2169       }
2170       break;
2171     case _adapter_drop_args:
2172       if (slots_pushed >= 0) {
2173         err = "adapter requires conversion subfield slots_pushed < 0";
2174       }
2175       break;
2176     case _adapter_collect_args:
2177     case _adapter_fold_args:
2178       if (slots_pushed > 2) {
2179         err = "adapter requires conversion subfield slots_pushed <= 2";
2180       }
2181       break;
2182     case _adapter_spread_args:
2183       if (slots_pushed < -1) {
2184         err = "adapter requires conversion subfield slots_pushed >= -1";
2185       }
2186       break;
2187     default:
2188       if (stack_move != 0) {
2189         err = "adapter has spurious stack_move conversion subfield";
2190       }
2191       break;
2192     }
2193     if (err == NULL && stack_move != slots_pushed * stack_move_unit()) {
2194       err = "stack_move conversion subfield must be multiple of stack_move_unit";
2195     }
2196   }
2197 
2198   if (err == NULL) {
2199     // Make sure this adapter's stack pushing is accurately recorded.
2200     int slots_pushed = stack_move / stack_move_unit();
2201     int this_vmslots = java_lang_invoke_MethodHandle::vmslots(mh());
2202     int target_vmslots = java_lang_invoke_MethodHandle::vmslots(target());
2203     int target_pushes = decode_MethodHandle_stack_pushes(target());
2204     if (slots_pushed != (target_vmslots - this_vmslots)) {
2205       err = "stack_move inconsistent with previous and current MethodType vmslots";
2206     } else {
2207       int this_pushes = decode_MethodHandle_stack_pushes(mh());
2208       if (slots_pushed + target_pushes != this_pushes) {
2209         if (this_pushes == 0)
2210           err = "adapter push count not initialized";
2211         else
2212           err = "adapter push count is wrong";
2213       }
2214     }
2215 
2216     // While we're at it, check that the stack motion decoder works:
2217     DEBUG_ONLY(int this_pushes = decode_MethodHandle_stack_pushes(mh()));
2218     assert(this_pushes == slots_pushed + target_pushes, "AMH stack motion must be correct");
2219   }
2220 
2221   if (err == NULL && vminfo != 0) {
2222     switch (ek) {
2223     case _adapter_swap_args:
2224     case _adapter_rot_args:
2225     case _adapter_prim_to_ref:
2226     case _adapter_collect_args:
2227     case _adapter_fold_args:
2228       break;                // OK
2229     default:
2230       err = "vminfo subfield is reserved to the JVM";
2231     }
2232   }
2233 
2234   // Do additional ad hoc checks.
2235   if (err == NULL) {
2236     switch (ek) {
2237     case _adapter_retype_only:
2238       err = check_method_type_passthrough(src_mtype(), dst_mtype(), false);
2239       break;
2240 
2241     case _adapter_retype_raw:
2242       err = check_method_type_passthrough(src_mtype(), dst_mtype(), true);
2243       break;
2244 
2245     case _adapter_check_cast:
2246       {
2247         // The actual value being checked must be a reference:
2248         err = check_argument_type_change(java_lang_invoke_MethodType::ptype(src_mtype(), argnum),
2249                                          object_java_mirror(), argnum);
2250         if (err != NULL)  break;
2251 
2252         // The output of the cast must fit with the destination argument:
2253         Handle cast_class = argument;
2254         err = check_method_type_conversion(src_mtype(),
2255                                            argnum, cast_class(),
2256                                            dst_mtype());
2257       }
2258       break;
2259 
2260       // %%% TO DO: continue in remaining cases to verify src/dst_mtype if VerifyMethodHandles
2261     }
2262   }
2263 
2264   if (err != NULL) {
2265     throw_InternalError_for_bad_conversion(conversion, err, THREAD);
2266     return;
2267   }
2268 
2269 }
2270 
2271 void MethodHandles::init_AdapterMethodHandle(Handle mh, Handle target, int argnum, TRAPS) {
2272   Handle argument   = java_lang_invoke_AdapterMethodHandle::argument(mh());
2273   int    argslot    = java_lang_invoke_AdapterMethodHandle::vmargslot(mh());
2274   jint   conversion = java_lang_invoke_AdapterMethodHandle::conversion(mh());
2275   jint   conv_op    = adapter_conversion_op(conversion);
2276 
2277   // adjust the adapter code to the internal EntryKind enumeration:
2278   EntryKind ek_orig = adapter_entry_kind(conv_op);
2279   EntryKind ek_opt  = ek_orig;  // may be optimized
2280   EntryKind ek_try;             // temp
2281 
2282   // Finalize the vmtarget field (Java initialized it to null).
2283   if (!java_lang_invoke_MethodHandle::is_instance(target())) {
2284     throw_InternalError_for_bad_conversion(conversion, "bad target", THREAD);
2285     return;
2286   }
2287   java_lang_invoke_AdapterMethodHandle::set_vmtarget(mh(), target());
2288 
2289   int stack_move = adapter_conversion_stack_move(conversion);
2290   BasicType src  = adapter_conversion_src_type(conversion);
2291   BasicType dest = adapter_conversion_dest_type(conversion);
2292   int vminfo     = adapter_conversion_vminfo(conversion); // should be zero
2293 
2294   int slots_pushed = stack_move / stack_move_unit();
2295 
2296   if (VerifyMethodHandles) {
2297     verify_AdapterMethodHandle(mh, argnum, CHECK);
2298   }
2299 
2300   const char* err = NULL;
2301 
2302   if (!conv_op_supported(conv_op)) {
2303     err = "adapter not yet implemented in the JVM";
2304   }
2305 
2306   // Now it's time to finish the case analysis and pick a MethodHandleEntry.
2307   switch (ek_orig) {
2308   case _adapter_retype_only:
2309   case _adapter_retype_raw:
2310   case _adapter_check_cast:
2311   case _adapter_dup_args:
2312   case _adapter_drop_args:
2313     // these work fine via general case code
2314     break;
2315 
2316   case _adapter_prim_to_prim:
2317     {
2318       // Non-subword cases are {int,float,long,double} -> {int,float,long,double}.
2319       // And, the {float,double} -> {int,long} cases must be handled by Java.
2320       switch (type2size[src] *4+ type2size[dest]) {
2321       case 1 *4+ 1:
2322         assert(src == T_INT || is_subword_type(src), "source is not float");
2323         // Subword-related cases are int -> {boolean,byte,char,short}.
2324         ek_opt = _adapter_opt_i2i;
2325         vminfo = adapter_prim_to_prim_subword_vminfo(dest);
2326         break;
2327       case 2 *4+ 1:
2328         if (src == T_LONG && (dest == T_INT || is_subword_type(dest))) {
2329           ek_opt = _adapter_opt_l2i;
2330           vminfo = adapter_prim_to_prim_subword_vminfo(dest);
2331         } else if (src == T_DOUBLE && dest == T_FLOAT) {
2332           ek_opt = _adapter_opt_d2f;
2333         } else {
2334           goto throw_not_impl;        // runs user code, hence could block
2335         }
2336         break;
2337       case 1 *4+ 2:
2338         if ((src == T_INT || is_subword_type(src)) && dest == T_LONG) {
2339           ek_opt = _adapter_opt_i2l;
2340         } else if (src == T_FLOAT && dest == T_DOUBLE) {
2341           ek_opt = _adapter_opt_f2d;
2342         } else {
2343           goto throw_not_impl;        // runs user code, hence could block
2344         }
2345         break;
2346       default:
2347         goto throw_not_impl;        // runs user code, hence could block
2348         break;
2349       }
2350     }
2351     break;
2352 
2353   case _adapter_ref_to_prim:
2354     {
2355       switch (type2size[dest]) {
2356       case 1:
2357         ek_opt = _adapter_opt_unboxi;
2358         vminfo = adapter_unbox_subword_vminfo(dest);
2359         break;
2360       case 2:
2361         ek_opt = _adapter_opt_unboxl;
2362         break;
2363       default:
2364         goto throw_not_impl;
2365         break;
2366       }
2367     }
2368     break;
2369 
2370   case _adapter_prim_to_ref:
2371     {
2372       assert(UseRicochetFrames, "else don't come here");
2373       // vminfo will be the location to insert the return value
2374       vminfo = argslot;
2375       ek_opt = _adapter_opt_collect_ref;
2376       ensure_vmlayout_field(target, CHECK);
2377       // for MethodHandleWalk:
2378       if (java_lang_invoke_AdapterMethodHandle::is_instance(argument()))
2379         ensure_vmlayout_field(argument, CHECK);
2380       if (!OptimizeMethodHandles)  break;
2381       switch (type2size[src]) {
2382       case 1:
2383         ek_try = EntryKind(_adapter_opt_filter_S0_ref + argslot);
2384         if (ek_try < _adapter_opt_collect_LAST &&
2385             ek_adapter_opt_collect_slot(ek_try) == argslot) {
2386           assert(ek_adapter_opt_collect_count(ek_try) == 1 &&
2387                  ek_adapter_opt_collect_type(ek_try) == T_OBJECT, "");
2388           ek_opt = ek_try;
2389           break;
2390         }
2391         // else downgrade to variable slot:
2392         ek_opt = _adapter_opt_collect_1_ref;
2393         break;
2394       case 2:
2395         ek_try = EntryKind(_adapter_opt_collect_2_S0_ref + argslot);
2396         if (ek_try < _adapter_opt_collect_LAST &&
2397             ek_adapter_opt_collect_slot(ek_try) == argslot) {
2398           assert(ek_adapter_opt_collect_count(ek_try) == 2 &&
2399                  ek_adapter_opt_collect_type(ek_try) == T_OBJECT, "");
2400           ek_opt = ek_try;
2401           break;
2402         }
2403         // else downgrade to variable slot:
2404         ek_opt = _adapter_opt_collect_2_ref;
2405         break;
2406       default:
2407         goto throw_not_impl;
2408         break;
2409       }
2410     }
2411     break;
2412 
2413   case _adapter_swap_args:
2414   case _adapter_rot_args:
2415     {
2416       int swap_slots = type2size[src];
2417       int src_slot   = argslot;
2418       int dest_slot  = vminfo;
2419       int rotate     = (ek_orig == _adapter_swap_args) ? 0 : (src_slot > dest_slot) ? 1 : -1;
2420       switch (swap_slots) {
2421       case 1:
2422         ek_opt = (!rotate    ? _adapter_opt_swap_1 :
2423                   rotate > 0 ? _adapter_opt_rot_1_up : _adapter_opt_rot_1_down);
2424         break;
2425       case 2:
2426         ek_opt = (!rotate    ? _adapter_opt_swap_2 :
2427                   rotate > 0 ? _adapter_opt_rot_2_up : _adapter_opt_rot_2_down);
2428         break;
2429       default:
2430         goto throw_not_impl;
2431         break;
2432       }
2433     }
2434     break;
2435 
2436   case _adapter_spread_args:
2437     {
2438 #ifdef TARGET_ARCH_NYI_6939861
2439       // ports before 6939861 supported only three kinds of spread ops
2440       if (!UseRicochetFrames) {
2441         int array_size   = slots_pushed + 1;
2442         assert(array_size >= 0, "");
2443         vminfo = array_size;
2444         switch (array_size) {
2445         case 0:   ek_opt = _adapter_opt_spread_0;       break;
2446         case 1:   ek_opt = _adapter_opt_spread_1;       break;
2447         default:  ek_opt = _adapter_opt_spread_more;    break;
2448         }
2449         break;
2450       }
2451 #endif //TARGET_ARCH_NYI_6939861
2452       // vminfo will be the required length of the array
2453       int array_size = (slots_pushed + 1) / (type2size[dest] == 2 ? 2 : 1);
2454       vminfo = array_size;
2455       // general case
2456       switch (dest) {
2457       case T_BOOLEAN : // fall through to T_BYTE:
2458       case T_BYTE    : ek_opt = _adapter_opt_spread_byte;    break;
2459       case T_CHAR    : ek_opt = _adapter_opt_spread_char;    break;
2460       case T_SHORT   : ek_opt = _adapter_opt_spread_short;   break;
2461       case T_INT     : ek_opt = _adapter_opt_spread_int;     break;
2462       case T_LONG    : ek_opt = _adapter_opt_spread_long;    break;
2463       case T_FLOAT   : ek_opt = _adapter_opt_spread_float;   break;
2464       case T_DOUBLE  : ek_opt = _adapter_opt_spread_double;  break;
2465       case T_OBJECT  : ek_opt = _adapter_opt_spread_ref;     break;
2466       case T_VOID    : if (array_size != 0)  goto throw_not_impl;
2467                        ek_opt = _adapter_opt_spread_ref;     break;
2468       default        : goto throw_not_impl;
2469       }
2470       assert(array_size == 0 ||  // it doesn't matter what the spreader is
2471              (ek_adapter_opt_spread_count(ek_opt) == -1 &&
2472               (ek_adapter_opt_spread_type(ek_opt) == dest ||
2473                (ek_adapter_opt_spread_type(ek_opt) == T_BYTE && dest == T_BOOLEAN))),
2474              err_msg("dest=%d ek_opt=%d", dest, ek_opt));
2475 
2476       if (array_size <= 0) {
2477         // since the general case does not handle length 0, this case is required:
2478         ek_opt = _adapter_opt_spread_0;
2479         break;
2480       }
2481       if (dest == T_OBJECT) {
2482         ek_try = EntryKind(_adapter_opt_spread_1_ref - 1 + array_size);
2483         if (ek_try < _adapter_opt_spread_LAST &&
2484             ek_adapter_opt_spread_count(ek_try) == array_size) {
2485           assert(ek_adapter_opt_spread_type(ek_try) == dest, "");
2486           ek_opt = ek_try;
2487           break;
2488         }
2489       }
2490       break;
2491     }
2492     break;
2493 
2494   case _adapter_collect_args:
2495     {
2496       assert(UseRicochetFrames, "else don't come here");
2497       int elem_slots = argument_slot_count(java_lang_invoke_MethodHandle::type(argument()));
2498       // vminfo will be the location to insert the return value
2499       vminfo = argslot;
2500       ensure_vmlayout_field(target, CHECK);
2501       ensure_vmlayout_field(argument, CHECK);
2502 
2503       // general case:
2504       switch (dest) {
2505       default       : if (!is_subword_type(dest))  goto throw_not_impl;
2506                     // else fall through:
2507       case T_INT    : ek_opt = _adapter_opt_collect_int;     break;
2508       case T_LONG   : ek_opt = _adapter_opt_collect_long;    break;
2509       case T_FLOAT  : ek_opt = _adapter_opt_collect_float;   break;
2510       case T_DOUBLE : ek_opt = _adapter_opt_collect_double;  break;
2511       case T_OBJECT : ek_opt = _adapter_opt_collect_ref;     break;
2512       case T_VOID   : ek_opt = _adapter_opt_collect_void;    break;
2513       }
2514       assert(ek_adapter_opt_collect_slot(ek_opt) == -1 &&
2515              ek_adapter_opt_collect_count(ek_opt) == -1 &&
2516              (ek_adapter_opt_collect_type(ek_opt) == dest ||
2517               ek_adapter_opt_collect_type(ek_opt) == T_INT && is_subword_type(dest)),
2518              "");
2519 
2520       if (dest == T_OBJECT && elem_slots == 1 && OptimizeMethodHandles) {
2521         // filter operation on a ref
2522         ek_try = EntryKind(_adapter_opt_filter_S0_ref + argslot);
2523         if (ek_try < _adapter_opt_collect_LAST &&
2524             ek_adapter_opt_collect_slot(ek_try) == argslot) {
2525           assert(ek_adapter_opt_collect_count(ek_try) == elem_slots &&
2526                  ek_adapter_opt_collect_type(ek_try) == dest, "");
2527           ek_opt = ek_try;
2528           break;
2529         }
2530         ek_opt = _adapter_opt_collect_1_ref;
2531         break;
2532       }
2533 
2534       if (dest == T_OBJECT && elem_slots == 2 && OptimizeMethodHandles) {
2535         // filter of two arguments
2536         ek_try = EntryKind(_adapter_opt_collect_2_S0_ref + argslot);
2537         if (ek_try < _adapter_opt_collect_LAST &&
2538             ek_adapter_opt_collect_slot(ek_try) == argslot) {
2539           assert(ek_adapter_opt_collect_count(ek_try) == elem_slots &&
2540                  ek_adapter_opt_collect_type(ek_try) == dest, "");
2541           ek_opt = ek_try;
2542           break;
2543         }
2544         ek_opt = _adapter_opt_collect_2_ref;
2545         break;
2546       }
2547 
2548       if (dest == T_OBJECT && OptimizeMethodHandles) {
2549         // try to use a fixed length adapter
2550         ek_try = EntryKind(_adapter_opt_collect_0_ref + elem_slots);
2551         if (ek_try < _adapter_opt_collect_LAST &&
2552             ek_adapter_opt_collect_count(ek_try) == elem_slots) {
2553           assert(ek_adapter_opt_collect_slot(ek_try) == -1 &&
2554                  ek_adapter_opt_collect_type(ek_try) == dest, "");
2555           ek_opt = ek_try;
2556           break;
2557         }
2558       }
2559 
2560       break;
2561     }
2562 
2563   case _adapter_fold_args:
2564     {
2565       assert(UseRicochetFrames, "else don't come here");
2566       int elem_slots = argument_slot_count(java_lang_invoke_MethodHandle::type(argument()));
2567       // vminfo will be the location to insert the return value
2568       vminfo = argslot + elem_slots;
2569       ensure_vmlayout_field(target, CHECK);
2570       ensure_vmlayout_field(argument, CHECK);
2571 
2572       switch (dest) {
2573       default       : if (!is_subword_type(dest))  goto throw_not_impl;
2574                     // else fall through:
2575       case T_INT    : ek_opt = _adapter_opt_fold_int;     break;
2576       case T_LONG   : ek_opt = _adapter_opt_fold_long;    break;
2577       case T_FLOAT  : ek_opt = _adapter_opt_fold_float;   break;
2578       case T_DOUBLE : ek_opt = _adapter_opt_fold_double;  break;
2579       case T_OBJECT : ek_opt = _adapter_opt_fold_ref;     break;
2580       case T_VOID   : ek_opt = _adapter_opt_fold_void;    break;
2581       }
2582       assert(ek_adapter_opt_collect_slot(ek_opt) == -1 &&
2583              ek_adapter_opt_collect_count(ek_opt) == -1 &&
2584              (ek_adapter_opt_collect_type(ek_opt) == dest ||
2585               ek_adapter_opt_collect_type(ek_opt) == T_INT && is_subword_type(dest)),
2586              "");
2587 
2588       if (dest == T_OBJECT && elem_slots == 0 && OptimizeMethodHandles) {
2589         // if there are no args, just pretend it's a collect
2590         ek_opt = _adapter_opt_collect_0_ref;
2591         break;
2592       }
2593 
2594       if (dest == T_OBJECT && OptimizeMethodHandles) {
2595         // try to use a fixed length adapter
2596         ek_try = EntryKind(_adapter_opt_fold_1_ref - 1 + elem_slots);
2597         if (ek_try < _adapter_opt_fold_LAST &&
2598             ek_adapter_opt_collect_count(ek_try) == elem_slots) {
2599           assert(ek_adapter_opt_collect_slot(ek_try) == -1 &&
2600                  ek_adapter_opt_collect_type(ek_try) == dest, "");
2601           ek_opt = ek_try;
2602           break;
2603         }
2604       }
2605 
2606       break;
2607     }
2608 
2609   default:
2610     // should have failed much earlier; must be a missing case here
2611     assert(false, "incomplete switch");
2612     // and fall through:
2613 
2614   throw_not_impl:
2615     if (err == NULL)
2616       err = "unknown adapter type";
2617     break;
2618   }
2619 
2620   if (err == NULL && (vminfo & CONV_VMINFO_MASK) != vminfo) {
2621     // should not happen, since vminfo is used to encode arg/slot indexes < 255
2622     err = "vminfo overflow";
2623   }
2624 
2625   if (err == NULL && !have_entry(ek_opt)) {
2626     err = "adapter stub for this kind of method handle is missing";
2627   }
2628 
2629   if (err == NULL && ek_opt == ek_orig) {
2630     switch (ek_opt) {
2631     case _adapter_prim_to_prim:
2632     case _adapter_ref_to_prim:
2633     case _adapter_prim_to_ref:
2634     case _adapter_swap_args:
2635     case _adapter_rot_args:
2636     case _adapter_collect_args:
2637     case _adapter_fold_args:
2638     case _adapter_spread_args:
2639       // should be handled completely by optimized cases; see above
2640       err = "init_AdapterMethodHandle should not issue this";
2641       break;
2642     }
2643   }
2644 
2645   if (err != NULL) {
2646     throw_InternalError_for_bad_conversion(conversion, err_msg("%s: conv_op %d ek_opt %d", err, conv_op, ek_opt), THREAD);
2647     return;
2648   }
2649 
2650   // Rebuild the conversion value; maybe parts of it were changed.
2651   jint new_conversion = adapter_conversion(conv_op, src, dest, stack_move, vminfo);
2652 
2653   // Finalize the conversion field.  (Note that it is final to Java code.)
2654   java_lang_invoke_AdapterMethodHandle::set_conversion(mh(), new_conversion);
2655 
2656   // Done!
2657   java_lang_invoke_MethodHandle::set_vmentry(mh(), entry(ek_opt));
2658 
2659   // There should be enough memory barriers on exit from native methods
2660   // to ensure that the MH is fully initialized to all threads before
2661   // Java code can publish it in global data structures.
2662 }
2663 
2664 void MethodHandles::ensure_vmlayout_field(Handle target, TRAPS) {
2665   Handle mtype(THREAD, java_lang_invoke_MethodHandle::type(target()));
2666   Handle mtform(THREAD, java_lang_invoke_MethodType::form(mtype()));
2667   if (mtform.is_null()) { THROW(vmSymbols::java_lang_InternalError()); }
2668   if (java_lang_invoke_MethodTypeForm::vmlayout_offset_in_bytes() > 0) {
2669     if (java_lang_invoke_MethodTypeForm::vmlayout(mtform()) == NULL) {
2670       // fill it in
2671       Handle erased_mtype(THREAD, java_lang_invoke_MethodTypeForm::erasedType(mtform()));
2672       TempNewSymbol erased_signature
2673         = java_lang_invoke_MethodType::as_signature(erased_mtype(), /*intern:*/true, CHECK);
2674       methodOop cookie
2675         = SystemDictionary::find_method_handle_invoke(vmSymbols::invokeExact_name(),
2676                                                       erased_signature,
2677                                                       SystemDictionaryHandles::Object_klass(),
2678                                                       THREAD);
2679       java_lang_invoke_MethodTypeForm::init_vmlayout(mtform(), cookie);
2680     }
2681   }
2682 }
2683 
2684 #ifdef ASSERT
2685 
2686 extern "C"
2687 void print_method_handle(oop mh);
2688 
2689 static void stress_method_handle_walk_impl(Handle mh, TRAPS) {
2690   if (StressMethodHandleWalk) {
2691     // Exercise the MethodHandleWalk code in various ways and validate
2692     // the resulting method oop.  Some of these produce output so they
2693     // are guarded under Verbose.
2694     ResourceMark rm;
2695     HandleMark hm;
2696     if (Verbose) {
2697       print_method_handle(mh());
2698     }
2699     TempNewSymbol name = SymbolTable::new_symbol("invoke", CHECK);
2700     Handle mt = java_lang_invoke_MethodHandle::type(mh());
2701     TempNewSymbol signature = java_lang_invoke_MethodType::as_signature(mt(), true, CHECK);
2702     MethodHandleCompiler mhc(mh, name, signature, 10000, false, CHECK);
2703     methodHandle m = mhc.compile(CHECK);
2704     if (Verbose) {
2705       m->print_codes();
2706     }
2707     InterpreterOopMap mask;
2708     OopMapCache::compute_one_oop_map(m, m->code_size() - 1, &mask);
2709     // compile to object code if -Xcomp or WizardMode
2710     if ((WizardMode ||
2711          CompilationPolicy::must_be_compiled(m))
2712         && !instanceKlass::cast(m->method_holder())->is_not_initialized()
2713         && CompilationPolicy::can_be_compiled(m)) {
2714       // Force compilation
2715       CompileBroker::compile_method(m, InvocationEntryBci,
2716                                     CompilationPolicy::policy()->initial_compile_level(),
2717                                     methodHandle(), 0, "StressMethodHandleWalk",
2718                                     CHECK);
2719     }
2720   }
2721 }
2722 
2723 static void stress_method_handle_walk(Handle mh, TRAPS) {
2724   stress_method_handle_walk_impl(mh, THREAD);
2725   if (HAS_PENDING_EXCEPTION) {
2726     oop ex = PENDING_EXCEPTION;
2727     CLEAR_PENDING_EXCEPTION;
2728     tty->print("StressMethodHandleWalk: ");
2729     java_lang_Throwable::print(ex, tty);
2730     tty->cr();
2731   }
2732 }
2733 #else
2734 
2735 static void stress_method_handle_walk(Handle mh, TRAPS) {}
2736 
2737 #endif
2738 
2739 //
2740 // Here are the native methods on sun.invoke.MethodHandleImpl.
2741 // They are the private interface between this JVM and the HotSpot-specific
2742 // Java code that implements JSR 292 method handles.
2743 //
2744 // Note:  We use a JVM_ENTRY macro to define each of these, for this is the way
2745 // that intrinsic (non-JNI) native methods are defined in HotSpot.
2746 //
2747 
2748 // direct method handles for invokestatic or invokespecial
2749 // void init(DirectMethodHandle self, MemberName ref, boolean doDispatch, Class<?> caller);
2750 JVM_ENTRY(void, MHN_init_DMH(JNIEnv *env, jobject igcls, jobject mh_jh,
2751                              jobject target_jh, jboolean do_dispatch, jobject caller_jh)) {
2752   ResourceMark rm;              // for error messages
2753 
2754   // This is the guy we are initializing:
2755   if (mh_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "self is null"); }
2756   Handle mh(THREAD, JNIHandles::resolve_non_null(mh_jh));
2757 
2758   // Early returns out of this method leave the DMH in an unfinished state.
2759   assert(java_lang_invoke_MethodHandle::vmentry(mh()) == NULL, "must be safely null");
2760 
2761   // which method are we really talking about?
2762   if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
2763   Handle target(THREAD, JNIHandles::resolve_non_null(target_jh));
2764   if (java_lang_invoke_MemberName::is_instance(target()) &&
2765       java_lang_invoke_MemberName::vmindex(target()) == VM_INDEX_UNINITIALIZED) {
2766     MethodHandles::resolve_MemberName(target, CHECK);
2767   }
2768 
2769   KlassHandle receiver_limit; int decode_flags = 0;
2770   methodHandle m = MethodHandles::decode_method(target(), receiver_limit, decode_flags);
2771   if (m.is_null()) { THROW_MSG(vmSymbols::java_lang_InternalError(), "no such method"); }
2772 
2773   // The trusted Java code that calls this method should already have performed
2774   // access checks on behalf of the given caller.  But, we can verify this.
2775   if (VerifyMethodHandles && caller_jh != NULL) {
2776     KlassHandle caller(THREAD, java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(caller_jh)));
2777     // If this were a bytecode, the first access check would be against
2778     // the "reference class" mentioned in the CONSTANT_Methodref.
2779     // We don't know at this point which class that was, and if we
2780     // check against m.method_holder we might get the wrong answer.
2781     // So we just make sure to handle this check when the resolution
2782     // happens, when we call resolve_MemberName.
2783     //
2784     // (A public class can inherit public members from private supers,
2785     // and it would be wrong to check access against the private super
2786     // if the original symbolic reference was against the public class.)
2787     //
2788     // If there were a bytecode, the next step would be to lookup the method
2789     // in the reference class, then then check the method's access bits.
2790     // Emulate LinkResolver::check_method_accessability.
2791     klassOop resolved_klass = m->method_holder();
2792     if (!Reflection::verify_field_access(caller->as_klassOop(),
2793                                          resolved_klass, resolved_klass,
2794                                          m->access_flags(),
2795                                          true)) {
2796       // %%% following cutout belongs in Reflection::verify_field_access?
2797       bool same_pm = Reflection::is_same_package_member(caller->as_klassOop(),
2798                                                         resolved_klass, THREAD);
2799       if (!same_pm) {
2800         THROW_MSG(vmSymbols::java_lang_InternalError(), m->name_and_sig_as_C_string());
2801       }
2802     }
2803   }
2804 
2805   MethodHandles::init_DirectMethodHandle(mh, m, (do_dispatch != JNI_FALSE), CHECK);
2806   stress_method_handle_walk(mh, CHECK);
2807 }
2808 JVM_END
2809 
2810 // bound method handles
2811 JVM_ENTRY(void, MHN_init_BMH(JNIEnv *env, jobject igcls, jobject mh_jh,
2812                              jobject target_jh, int argnum)) {
2813   ResourceMark rm;              // for error messages
2814 
2815   // This is the guy we are initializing:
2816   if (mh_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "self is null"); }
2817   Handle mh(THREAD, JNIHandles::resolve_non_null(mh_jh));
2818 
2819   // Early returns out of this method leave the BMH in an unfinished state.
2820   assert(java_lang_invoke_MethodHandle::vmentry(mh()) == NULL, "must be safely null");
2821 
2822   if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
2823   Handle target(THREAD, JNIHandles::resolve_non_null(target_jh));
2824 
2825   if (!java_lang_invoke_MethodHandle::is_instance(target())) {
2826     // Target object is a reflective method.  (%%% Do we need this alternate path?)
2827     Untested("init_BMH of non-MH");
2828     if (argnum != 0) { THROW(vmSymbols::java_lang_InternalError()); }
2829     KlassHandle receiver_limit; int decode_flags = 0;
2830     methodHandle m = MethodHandles::decode_method(target(), receiver_limit, decode_flags);
2831     MethodHandles::init_BoundMethodHandle_with_receiver(mh, m,
2832                                                        receiver_limit,
2833                                                        decode_flags,
2834                                                        CHECK);
2835   } else {
2836     // Build a BMH on top of a DMH or another BMH:
2837     MethodHandles::init_BoundMethodHandle(mh, target, argnum, CHECK);
2838   }
2839 
2840   if (StressMethodHandleWalk) {
2841     if (mh->klass() == SystemDictionary::BoundMethodHandle_klass())
2842       stress_method_handle_walk(mh, CHECK);
2843     // else don't, since the subclass has not yet initialized its own fields
2844   }
2845 }
2846 JVM_END
2847 
2848 // adapter method handles
2849 JVM_ENTRY(void, MHN_init_AMH(JNIEnv *env, jobject igcls, jobject mh_jh,
2850                              jobject target_jh, int argnum)) {
2851   // This is the guy we are initializing:
2852   if (mh_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "self is null"); }
2853   if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
2854   Handle mh(THREAD, JNIHandles::resolve_non_null(mh_jh));
2855   Handle target(THREAD, JNIHandles::resolve_non_null(target_jh));
2856 
2857   // Early returns out of this method leave the AMH in an unfinished state.
2858   assert(java_lang_invoke_MethodHandle::vmentry(mh()) == NULL, "must be safely null");
2859 
2860   MethodHandles::init_AdapterMethodHandle(mh, target, argnum, CHECK);
2861   stress_method_handle_walk(mh, CHECK);
2862 }
2863 JVM_END
2864 
2865 // method type forms
2866 JVM_ENTRY(void, MHN_init_MT(JNIEnv *env, jobject igcls, jobject erased_jh)) {
2867   if (erased_jh == NULL)  return;
2868   if (TraceMethodHandles) {
2869     tty->print("creating MethodType form ");
2870     if (WizardMode || Verbose) {   // Warning: this calls Java code on the MH!
2871       // call Object.toString()
2872       Symbol* name = vmSymbols::toString_name();
2873       Symbol* sig = vmSymbols::void_string_signature();
2874       JavaCallArguments args(Handle(THREAD, JNIHandles::resolve_non_null(erased_jh)));
2875       JavaValue result(T_OBJECT);
2876       JavaCalls::call_virtual(&result, SystemDictionary::Object_klass(), name, sig,
2877                               &args, CHECK);
2878       Handle str(THREAD, (oop)result.get_jobject());
2879       java_lang_String::print(str, tty);
2880     }
2881     tty->cr();
2882   }
2883 }
2884 JVM_END
2885 
2886 // debugging and reflection
2887 JVM_ENTRY(jobject, MHN_getTarget(JNIEnv *env, jobject igcls, jobject mh_jh, jint format)) {
2888   Handle mh(THREAD, JNIHandles::resolve(mh_jh));
2889   if (!java_lang_invoke_MethodHandle::is_instance(mh())) {
2890     THROW_NULL(vmSymbols::java_lang_IllegalArgumentException());
2891   }
2892   oop target = MethodHandles::encode_target(mh, format, CHECK_NULL);
2893   return JNIHandles::make_local(THREAD, target);
2894 }
2895 JVM_END
2896 
2897 JVM_ENTRY(jint, MHN_getConstant(JNIEnv *env, jobject igcls, jint which)) {
2898   switch (which) {
2899   case MethodHandles::GC_JVM_PUSH_LIMIT:
2900     guarantee(MethodHandlePushLimit >= 2 && MethodHandlePushLimit <= 0xFF,
2901               "MethodHandlePushLimit parameter must be in valid range");
2902     return MethodHandlePushLimit;
2903   case MethodHandles::GC_JVM_STACK_MOVE_UNIT:
2904     // return number of words per slot, signed according to stack direction
2905     return MethodHandles::stack_move_unit();
2906   case MethodHandles::GC_CONV_OP_IMPLEMENTED_MASK:
2907     return MethodHandles::adapter_conversion_ops_supported_mask();
2908   case MethodHandles::GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS:
2909     return MethodHandles::OP_ROT_ARGS_DOWN_LIMIT_BIAS;
2910   }
2911   return 0;
2912 }
2913 JVM_END
2914 
2915 #ifndef PRODUCT
2916 #define EACH_NAMED_CON(template) \
2917   /* hold back this one until JDK stabilizes */ \
2918   /* template(MethodHandles,GC_JVM_PUSH_LIMIT) */  \
2919   /* hold back this one until JDK stabilizes */ \
2920   /* template(MethodHandles,GC_JVM_STACK_MOVE_UNIT) */ \
2921   /* hold back this one until JDK stabilizes */ \
2922   /* template(MethodHandles,GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS) */ \
2923     template(MethodHandles,ETF_HANDLE_OR_METHOD_NAME) \
2924     template(MethodHandles,ETF_DIRECT_HANDLE) \
2925     template(MethodHandles,ETF_METHOD_NAME) \
2926     template(MethodHandles,ETF_REFLECT_METHOD) \
2927     template(java_lang_invoke_MemberName,MN_IS_METHOD) \
2928     template(java_lang_invoke_MemberName,MN_IS_CONSTRUCTOR) \
2929     template(java_lang_invoke_MemberName,MN_IS_FIELD) \
2930     template(java_lang_invoke_MemberName,MN_IS_TYPE) \
2931     template(java_lang_invoke_MemberName,MN_SEARCH_SUPERCLASSES) \
2932     template(java_lang_invoke_MemberName,MN_SEARCH_INTERFACES) \
2933     template(java_lang_invoke_MemberName,VM_INDEX_UNINITIALIZED) \
2934     template(java_lang_invoke_AdapterMethodHandle,OP_RETYPE_ONLY) \
2935     template(java_lang_invoke_AdapterMethodHandle,OP_RETYPE_RAW) \
2936     template(java_lang_invoke_AdapterMethodHandle,OP_CHECK_CAST) \
2937     template(java_lang_invoke_AdapterMethodHandle,OP_PRIM_TO_PRIM) \
2938     template(java_lang_invoke_AdapterMethodHandle,OP_REF_TO_PRIM) \
2939     template(java_lang_invoke_AdapterMethodHandle,OP_PRIM_TO_REF) \
2940     template(java_lang_invoke_AdapterMethodHandle,OP_SWAP_ARGS) \
2941     template(java_lang_invoke_AdapterMethodHandle,OP_ROT_ARGS) \
2942     template(java_lang_invoke_AdapterMethodHandle,OP_DUP_ARGS) \
2943     template(java_lang_invoke_AdapterMethodHandle,OP_DROP_ARGS) \
2944     template(java_lang_invoke_AdapterMethodHandle,OP_COLLECT_ARGS) \
2945     template(java_lang_invoke_AdapterMethodHandle,OP_SPREAD_ARGS) \
2946       /* hold back this one until JDK stabilizes */ \
2947       /*template(java_lang_invoke_AdapterMethodHandle,CONV_OP_LIMIT)*/  \
2948     template(java_lang_invoke_AdapterMethodHandle,CONV_OP_MASK) \
2949     template(java_lang_invoke_AdapterMethodHandle,CONV_VMINFO_MASK) \
2950     template(java_lang_invoke_AdapterMethodHandle,CONV_VMINFO_SHIFT) \
2951     template(java_lang_invoke_AdapterMethodHandle,CONV_OP_SHIFT) \
2952     template(java_lang_invoke_AdapterMethodHandle,CONV_DEST_TYPE_SHIFT) \
2953     template(java_lang_invoke_AdapterMethodHandle,CONV_SRC_TYPE_SHIFT) \
2954     template(java_lang_invoke_AdapterMethodHandle,CONV_STACK_MOVE_SHIFT) \
2955     template(java_lang_invoke_AdapterMethodHandle,CONV_STACK_MOVE_MASK) \
2956     /*end*/
2957 
2958 #define ONE_PLUS(scope,value) 1+
2959 static const int con_value_count = EACH_NAMED_CON(ONE_PLUS) 0;
2960 #define VALUE_COMMA(scope,value) scope::value,
2961 static const int con_values[con_value_count+1] = { EACH_NAMED_CON(VALUE_COMMA) 0 };
2962 #define STRING_NULL(scope,value) #value "\0"
2963 static const char con_names[] = { EACH_NAMED_CON(STRING_NULL) };
2964 
2965 #undef ONE_PLUS
2966 #undef VALUE_COMMA
2967 #undef STRING_NULL
2968 #undef EACH_NAMED_CON
2969 #endif
2970 
2971 JVM_ENTRY(jint, MHN_getNamedCon(JNIEnv *env, jobject igcls, jint which, jobjectArray box_jh)) {
2972 #ifndef PRODUCT
2973   if (which >= 0 && which < con_value_count) {
2974     int con = con_values[which];
2975     objArrayHandle box(THREAD, (objArrayOop) JNIHandles::resolve(box_jh));
2976     if (box.not_null() && box->klass() == Universe::objectArrayKlassObj() && box->length() > 0) {
2977       const char* str = &con_names[0];
2978       for (int i = 0; i < which; i++)
2979         str += strlen(str) + 1;   // skip name and null
2980       oop name = java_lang_String::create_oop_from_str(str, CHECK_0);  // possible safepoint
2981       box->obj_at_put(0, name);
2982     }
2983     return con;
2984   }
2985 #endif
2986   return 0;
2987 }
2988 JVM_END
2989 
2990 // void init(MemberName self, AccessibleObject ref)
2991 JVM_ENTRY(void, MHN_init_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jobject target_jh)) {
2992   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
2993   if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
2994   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
2995   oop target_oop = JNIHandles::resolve_non_null(target_jh);
2996   MethodHandles::init_MemberName(mname(), target_oop);
2997 }
2998 JVM_END
2999 
3000 // void expand(MemberName self)
3001 JVM_ENTRY(void, MHN_expand_Mem(JNIEnv *env, jobject igcls, jobject mname_jh)) {
3002   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
3003   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
3004   MethodHandles::expand_MemberName(mname, 0, CHECK);
3005 }
3006 JVM_END
3007 
3008 // void resolve(MemberName self, Class<?> caller)
3009 JVM_ENTRY(void, MHN_resolve_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jclass caller_jh)) {
3010   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
3011   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
3012 
3013   // The trusted Java code that calls this method should already have performed
3014   // access checks on behalf of the given caller.  But, we can verify this.
3015   if (VerifyMethodHandles && caller_jh != NULL) {
3016     klassOop reference_klass = java_lang_Class::as_klassOop(java_lang_invoke_MemberName::clazz(mname()));
3017     if (reference_klass != NULL) {
3018       // Emulate LinkResolver::check_klass_accessability.
3019       klassOop caller = java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(caller_jh));
3020       if (!Reflection::verify_class_access(caller,
3021                                            reference_klass,
3022                                            true)) {
3023         THROW_MSG(vmSymbols::java_lang_InternalError(), Klass::cast(reference_klass)->external_name());
3024       }
3025     }
3026   }
3027 
3028   MethodHandles::resolve_MemberName(mname, CHECK);
3029 }
3030 JVM_END
3031 
3032 //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
3033 //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
3034 JVM_ENTRY(jint, MHN_getMembers(JNIEnv *env, jobject igcls,
3035                                jclass clazz_jh, jstring name_jh, jstring sig_jh,
3036                                int mflags, jclass caller_jh, jint skip, jobjectArray results_jh)) {
3037   if (clazz_jh == NULL || results_jh == NULL)  return -1;
3038   KlassHandle k(THREAD, java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(clazz_jh)));
3039 
3040   objArrayHandle results(THREAD, (objArrayOop) JNIHandles::resolve(results_jh));
3041   if (results.is_null() || !results->is_objArray())  return -1;
3042 
3043   TempNewSymbol name = NULL;
3044   TempNewSymbol sig = NULL;
3045   if (name_jh != NULL) {
3046     name = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(name_jh));
3047     if (name == NULL)  return 0; // a match is not possible
3048   }
3049   if (sig_jh != NULL) {
3050     sig = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(sig_jh));
3051     if (sig == NULL)  return 0; // a match is not possible
3052   }
3053 
3054   KlassHandle caller;
3055   if (caller_jh != NULL) {
3056     oop caller_oop = JNIHandles::resolve_non_null(caller_jh);
3057     if (!java_lang_Class::is_instance(caller_oop))  return -1;
3058     caller = KlassHandle(THREAD, java_lang_Class::as_klassOop(caller_oop));
3059   }
3060 
3061   if (name != NULL && sig != NULL && results.not_null()) {
3062     // try a direct resolve
3063     // %%% TO DO
3064   }
3065 
3066   int res = MethodHandles::find_MemberNames(k(), name, sig, mflags,
3067                                             caller(), skip, results());
3068   // TO DO: expand at least some of the MemberNames, to avoid massive callbacks
3069   return res;
3070 }
3071 JVM_END
3072 
3073 methodOop MethodHandles::resolve_raise_exception_method(TRAPS) {
3074   if (_raise_exception_method != NULL) {
3075     // no need to do it twice
3076     return raise_exception_method();
3077   }
3078   // LinkResolver::resolve_invokedynamic can reach this point
3079   // because an invokedynamic has failed very early (7049415)
3080   KlassHandle MHN_klass = SystemDictionaryHandles::MethodHandleNatives_klass();
3081   if (MHN_klass.not_null()) {
3082     TempNewSymbol raiseException_name = SymbolTable::new_symbol("raiseException", CHECK_NULL);
3083     TempNewSymbol raiseException_sig = SymbolTable::new_symbol("(ILjava/lang/Object;Ljava/lang/Object;)V", CHECK_NULL);
3084     methodOop raiseException_method  = instanceKlass::cast(MHN_klass->as_klassOop())
3085                   ->find_method(raiseException_name, raiseException_sig);
3086     if (raiseException_method != NULL && raiseException_method->is_static()) {
3087       return raiseException_method;
3088     }
3089   }
3090   // not found; let the caller deal with it
3091   return NULL;
3092 }
3093 void MethodHandles::raise_exception(int code, oop actual, oop required, TRAPS) {
3094   methodOop raiseException_method = resolve_raise_exception_method(CHECK);
3095   if (raiseException_method != NULL &&
3096       instanceKlass::cast(raiseException_method->method_holder())->is_not_initialized()) {
3097     instanceKlass::cast(raiseException_method->method_holder())->initialize(CHECK);
3098     // it had better be resolved by now, or maybe JSR 292 failed to load
3099     raiseException_method = raise_exception_method();
3100   }
3101   if (raiseException_method == NULL) {
3102     THROW_MSG(vmSymbols::java_lang_InternalError(), "no raiseException method");
3103   }
3104   JavaCallArguments args;
3105   args.push_int(code);
3106   args.push_oop(actual);
3107   args.push_oop(required);
3108   JavaValue result(T_VOID);
3109   JavaCalls::call(&result, raiseException_method, &args, CHECK);
3110 }
3111 
3112 JVM_ENTRY(jobject, MH_invoke_UOE(JNIEnv *env, jobject igmh, jobjectArray igargs)) {
3113     TempNewSymbol UOE_name = SymbolTable::new_symbol("java/lang/UnsupportedOperationException", CHECK_NULL);
3114     THROW_MSG_NULL(UOE_name, "MethodHandle.invoke cannot be invoked reflectively");
3115     return NULL;
3116 }
3117 JVM_END
3118 
3119 JVM_ENTRY(jobject, MH_invokeExact_UOE(JNIEnv *env, jobject igmh, jobjectArray igargs)) {
3120     TempNewSymbol UOE_name = SymbolTable::new_symbol("java/lang/UnsupportedOperationException", CHECK_NULL);
3121     THROW_MSG_NULL(UOE_name, "MethodHandle.invokeExact cannot be invoked reflectively");
3122     return NULL;
3123 }
3124 JVM_END
3125 
3126 
3127 /// JVM_RegisterMethodHandleMethods
3128 
3129 #define LANG "Ljava/lang/"
3130 #define JLINV "Ljava/lang/invoke/"
3131 
3132 #define OBJ   LANG"Object;"
3133 #define CLS   LANG"Class;"
3134 #define STRG  LANG"String;"
3135 #define MT    JLINV"MethodType;"
3136 #define MH    JLINV"MethodHandle;"
3137 #define MEM   JLINV"MemberName;"
3138 #define AMH   JLINV"AdapterMethodHandle;"
3139 #define BMH   JLINV"BoundMethodHandle;"
3140 #define DMH   JLINV"DirectMethodHandle;"
3141 
3142 #define CC (char*)  /*cast a literal from (const char*)*/
3143 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
3144 
3145 // These are the native methods on sun.invoke.MethodHandleNatives.
3146 static JNINativeMethod methods[] = {
3147   // void init(MemberName self, AccessibleObject ref)
3148   {CC"init",                    CC"("AMH""MH"I)V",              FN_PTR(MHN_init_AMH)},
3149   {CC"init",                    CC"("BMH""OBJ"I)V",             FN_PTR(MHN_init_BMH)},
3150   {CC"init",                    CC"("DMH""OBJ"Z"CLS")V",        FN_PTR(MHN_init_DMH)},
3151   {CC"init",                    CC"("MT")V",                    FN_PTR(MHN_init_MT)},
3152   {CC"init",                    CC"("MEM""OBJ")V",              FN_PTR(MHN_init_Mem)},
3153   {CC"expand",                  CC"("MEM")V",                   FN_PTR(MHN_expand_Mem)},
3154   {CC"resolve",                 CC"("MEM""CLS")V",              FN_PTR(MHN_resolve_Mem)},
3155   {CC"getTarget",               CC"("MH"I)"OBJ,                 FN_PTR(MHN_getTarget)},
3156   {CC"getConstant",             CC"(I)I",                       FN_PTR(MHN_getConstant)},
3157   //  static native int getNamedCon(int which, Object[] name)
3158   {CC"getNamedCon",             CC"(I["OBJ")I",                 FN_PTR(MHN_getNamedCon)},
3159   //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
3160   //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
3161   {CC"getMembers",              CC"("CLS""STRG""STRG"I"CLS"I["MEM")I",  FN_PTR(MHN_getMembers)}
3162 };
3163 
3164 static JNINativeMethod invoke_methods[] = {
3165   // void init(MemberName self, AccessibleObject ref)
3166   {CC"invoke",                  CC"(["OBJ")"OBJ,                FN_PTR(MH_invoke_UOE)},
3167   {CC"invokeExact",             CC"(["OBJ")"OBJ,                FN_PTR(MH_invokeExact_UOE)}
3168 };
3169 
3170 // This one function is exported, used by NativeLookup.
3171 
3172 JVM_ENTRY(void, JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass MHN_class)) {
3173   assert(MethodHandles::spot_check_entry_names(), "entry enum is OK");
3174 
3175   if (!EnableInvokeDynamic) {
3176     warning("JSR 292 is disabled in this JVM.  Use -XX:+UnlockDiagnosticVMOptions -XX:+EnableInvokeDynamic to enable.");
3177     return;  // bind nothing
3178   }
3179 
3180   bool enable_MH = true;
3181 
3182   {
3183     ThreadToNativeFromVM ttnfv(thread);
3184 
3185     int status = env->RegisterNatives(MHN_class, methods, sizeof(methods)/sizeof(JNINativeMethod));
3186     if (!env->ExceptionOccurred()) {
3187       const char* L_MH_name = (JLINV "MethodHandle");
3188       const char* MH_name = L_MH_name+1;
3189       jclass MH_class = env->FindClass(MH_name);
3190       status = env->RegisterNatives(MH_class, invoke_methods, sizeof(invoke_methods)/sizeof(JNINativeMethod));
3191     }
3192     if (env->ExceptionOccurred()) {
3193       MethodHandles::set_enabled(false);
3194       warning("JSR 292 method handle code is mismatched to this JVM.  Disabling support.");
3195       enable_MH = false;
3196       env->ExceptionClear();
3197     }
3198   }
3199 
3200   if (enable_MH) {
3201     methodOop raiseException_method = MethodHandles::resolve_raise_exception_method(CHECK);
3202     if (raiseException_method != NULL) {
3203       MethodHandles::set_raise_exception_method(raiseException_method);
3204     } else {
3205       warning("JSR 292 method handle code is mismatched to this JVM.  Disabling support.");
3206       enable_MH = false;
3207     }
3208   }
3209 
3210   if (enable_MH) {
3211     MethodHandles::generate_adapters();
3212     MethodHandles::set_enabled(true);
3213   }
3214 }
3215 JVM_END