1 /*
   2  * Copyright (c) 2008, 2014, 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/jvmtiRedefineClassesTrace.hpp"
  33 #include "prims/methodHandles.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 /*
  42  * JSR 292 reference implementation: method handles
  43  * The JDK 7 reference implementation represented method handle
  44  * combinations as chains.  Each link in the chain had a "vmentry"
  45  * field which pointed at a bit of assembly code which performed
  46  * one transformation before dispatching to the next link in the chain.
  47  *
  48  * The current reference implementation pushes almost all code generation
  49  * responsibility to (trusted) Java code.  A method handle contains a
  50  * pointer to its "LambdaForm", which embodies all details of the method
  51  * handle's behavior.  The LambdaForm is a normal Java object, managed
  52  * by a runtime coded in Java.
  53  */
  54 
  55 bool MethodHandles::_enabled = false; // set true after successful native linkage
  56 MethodHandlesAdapterBlob* MethodHandles::_adapter_code = NULL;
  57 
  58 //------------------------------------------------------------------------------
  59 // MethodHandles::generate_adapters
  60 //
  61 void MethodHandles::generate_adapters() {
  62   if (!EnableInvokeDynamic || SystemDictionary::MethodHandle_klass() == NULL)  return;
  63 
  64   assert(_adapter_code == NULL, "generate only once");
  65 
  66   ResourceMark rm;
  67   TraceTime timer("MethodHandles adapters generation", TraceStartupTime);
  68   _adapter_code = MethodHandlesAdapterBlob::create(adapter_code_size);
  69   if (_adapter_code == NULL)
  70     vm_exit_out_of_memory(adapter_code_size, "CodeCache: no room for MethodHandles adapters");
  71   {
  72     CodeBuffer code(_adapter_code);
  73     MethodHandlesAdapterGenerator g(&code);
  74     g.generate();
  75     code.log_section_sizes("MethodHandlesAdapterBlob");
  76   }
  77 }
  78 
  79 //------------------------------------------------------------------------------
  80 // MethodHandlesAdapterGenerator::generate
  81 //
  82 void MethodHandlesAdapterGenerator::generate() {
  83   // Generate generic method handle adapters.
  84   // Generate interpreter entries
  85   for (Interpreter::MethodKind mk = Interpreter::method_handle_invoke_FIRST;
  86        mk <= Interpreter::method_handle_invoke_LAST;
  87        mk = Interpreter::MethodKind(1 + (int)mk)) {
  88     vmIntrinsics::ID iid = Interpreter::method_handle_intrinsic(mk);
  89     StubCodeMark mark(this, "MethodHandle::interpreter_entry", vmIntrinsics::name_at(iid));
  90     address entry = MethodHandles::generate_method_handle_interpreter_entry(_masm, iid);
  91     if (entry != NULL) {
  92       Interpreter::set_entry_for_kind(mk, entry);
  93     }
  94     // If the entry is not set, it will throw AbstractMethodError.
  95   }
  96 }
  97 
  98 void MethodHandles::set_enabled(bool z) {
  99   if (_enabled != z) {
 100     guarantee(z && EnableInvokeDynamic, "can only enable once, and only if -XX:+EnableInvokeDynamic");
 101     _enabled = z;
 102   }
 103 }
 104 
 105 // MemberName support
 106 
 107 // import java_lang_invoke_MemberName.*
 108 enum {
 109   IS_METHOD      = java_lang_invoke_MemberName::MN_IS_METHOD,
 110   IS_CONSTRUCTOR = java_lang_invoke_MemberName::MN_IS_CONSTRUCTOR,
 111   IS_FIELD       = java_lang_invoke_MemberName::MN_IS_FIELD,
 112   IS_TYPE        = java_lang_invoke_MemberName::MN_IS_TYPE,
 113   REFERENCE_KIND_SHIFT = java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT,
 114   REFERENCE_KIND_MASK  = java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK,
 115   SEARCH_SUPERCLASSES = java_lang_invoke_MemberName::MN_SEARCH_SUPERCLASSES,
 116   SEARCH_INTERFACES   = java_lang_invoke_MemberName::MN_SEARCH_INTERFACES,
 117   ALL_KINDS      = IS_METHOD | IS_CONSTRUCTOR | IS_FIELD | IS_TYPE
 118 };
 119 
 120 Handle MethodHandles::new_MemberName(TRAPS) {
 121   Handle empty;
 122   instanceKlassHandle k(THREAD, SystemDictionary::MemberName_klass());
 123   if (!k->is_initialized())  k->initialize(CHECK_(empty));
 124   return Handle(THREAD, k->allocate_instance(THREAD));
 125 }
 126 
 127 oop MethodHandles::init_MemberName(Handle mname, Handle target) {
 128   Thread* thread = Thread::current();
 129   oop target_oop = target();
 130   klassOop target_klass = target_oop->klass();
 131   if (target_klass == SystemDictionary::reflect_Field_klass()) {
 132     oop clazz = java_lang_reflect_Field::clazz(target_oop); // fd.field_holder()
 133     int slot  = java_lang_reflect_Field::slot(target_oop);  // fd.index()
 134     int mods  = java_lang_reflect_Field::modifiers(target_oop);
 135     oop type  = java_lang_reflect_Field::type(target_oop);
 136     oop name  = java_lang_reflect_Field::name(target_oop);
 137     KlassHandle k(thread, java_lang_Class::as_klassOop(clazz));
 138     intptr_t offset = instanceKlass::cast(k())->field_offset(slot);
 139     return init_field_MemberName(mname, k, accessFlags_from(mods), type, name, offset);
 140   } else if (target_klass == SystemDictionary::reflect_Method_klass()) {
 141     oop clazz  = java_lang_reflect_Method::clazz(target_oop);
 142     int slot   = java_lang_reflect_Method::slot(target_oop);
 143     KlassHandle k(thread, java_lang_Class::as_klassOop(clazz));
 144     if (!k.is_null() && k->oop_is_instance()) {
 145       methodOop m = instanceKlass::cast(k())->method_with_idnum(slot);
 146       return init_method_MemberName(mname, m, true, k);
 147     }
 148   } else if (target_klass == SystemDictionary::reflect_Constructor_klass()) {
 149     oop clazz  = java_lang_reflect_Constructor::clazz(target_oop);
 150     int slot   = java_lang_reflect_Constructor::slot(target_oop);
 151     KlassHandle k(thread, java_lang_Class::as_klassOop(clazz));
 152     if (!k.is_null() && k->oop_is_instance()) {
 153       methodOop m = instanceKlass::cast(k())->method_with_idnum(slot);
 154       return init_method_MemberName(mname, m, false, k);
 155     }
 156   } else if (target_klass == SystemDictionary::MemberName_klass()) {
 157     // Note: This only works if the MemberName has already been resolved.
 158     oop clazz        = java_lang_invoke_MemberName::clazz(target_oop);
 159     int flags        = java_lang_invoke_MemberName::flags(target_oop);
 160     oop vmtarget     = java_lang_invoke_MemberName::vmtarget(target_oop);
 161     intptr_t vmindex = java_lang_invoke_MemberName::vmindex(target_oop);
 162     KlassHandle k(thread, java_lang_Class::as_klassOop(clazz));
 163     int ref_kind     = (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
 164     if (vmtarget == NULL)  return NULL;  // not resolved
 165     if ((flags & IS_FIELD) != 0) {
 166       assert(vmtarget->is_klass(), "field vmtarget is klassOop");
 167       int basic_mods = (ref_kind_is_static(ref_kind) ? JVM_ACC_STATIC : 0);
 168       // FIXME:  how does k (receiver_limit) contribute?
 169       KlassHandle k_vmtarget(thread, klassOop(vmtarget));
 170       return init_field_MemberName(mname, k_vmtarget, accessFlags_from(basic_mods), NULL, NULL, vmindex);
 171     } else if ((flags & (IS_METHOD | IS_CONSTRUCTOR)) != 0) {
 172       assert(vmtarget->is_method(), "method or constructor vmtarget is methodOop");
 173       return init_method_MemberName(mname, methodOop(vmtarget), ref_kind_does_dispatch(ref_kind), k);
 174     } else {
 175       return NULL;
 176     }
 177   }
 178   return NULL;
 179 }
 180 
 181 oop MethodHandles::init_method_MemberName(Handle mname, methodOop m, bool do_dispatch,
 182                                           KlassHandle resolved_klass_h) {
 183   klassOop resolved_klass = resolved_klass_h();
 184   AccessFlags mods = m->access_flags();
 185   int flags = (jushort)( mods.as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS );
 186   int vmindex = methodOopDesc::nonvirtual_vtable_index; // implies never any dispatch
 187   bool is_itable_call = false;
 188   klassOop m_klass = m->method_holder();
 189   // resolved_klass is a copy of CallInfo::resolved_klass, if available
 190   if (resolved_klass == NULL)
 191     resolved_klass = m_klass;
 192   if (m->is_initializer()) {
 193     flags |= IS_CONSTRUCTOR | (JVM_REF_invokeSpecial << REFERENCE_KIND_SHIFT);
 194   } else if (mods.is_static()) {
 195     flags |= IS_METHOD | (JVM_REF_invokeStatic << REFERENCE_KIND_SHIFT);
 196   } else if (resolved_klass != m_klass &&
 197              !Klass::cast(resolved_klass)->is_subtype_of(m_klass)) {
 198     return NULL;  // bad receiver limit
 199   } else if (Klass::cast(resolved_klass)->is_interface() &&
 200              Klass::cast(m_klass)->is_interface()) {
 201     flags |= IS_METHOD | (JVM_REF_invokeInterface << REFERENCE_KIND_SHIFT);
 202     vmindex = klassItable::compute_itable_index(m);
 203     is_itable_call = true;
 204   } else if (m_klass != resolved_klass && Klass::cast(m_klass)->is_interface()) {
 205     flags |= IS_METHOD | (JVM_REF_invokeVirtual << REFERENCE_KIND_SHIFT);
 206     // it is a miranda method, so m->vtable_index is not what we want
 207     ResourceMark rm;
 208     klassVtable* vt = instanceKlass::cast(resolved_klass)->vtable();
 209     vmindex = vt->index_of_miranda(m->name(), m->signature());
 210   } else if (!do_dispatch || m->can_be_statically_bound()) {
 211     flags |= IS_METHOD | (JVM_REF_invokeSpecial << REFERENCE_KIND_SHIFT);
 212   } else {
 213     flags |= IS_METHOD | (JVM_REF_invokeVirtual << REFERENCE_KIND_SHIFT);
 214     vmindex = m->vtable_index();
 215   }
 216 
 217   if (vmindex >= 0 && !is_itable_call) {
 218     if (Klass::cast(m_klass)->is_interface()) {
 219       // This is a vtable call to an interface method (abstract "miranda method").
 220       // The vtable index is meaningless without a class (not interface) receiver type, so get one.
 221       // (LinkResolver should help us figure this out.)
 222       KlassHandle m_klass_non_interface = resolved_klass;
 223       if (m_klass_non_interface->is_interface()) {
 224         m_klass_non_interface = SystemDictionary::Object_klass();
 225 #ifdef ASSERT
 226         { ResourceMark rm;
 227           methodOop m2 = m_klass_non_interface->vtable()->method_at(vmindex);
 228           assert(m->name() == m2->name() && m->signature() == m2->signature(),
 229                  err_msg("at %d, %s != %s", vmindex,
 230                          m->name_and_sig_as_C_string(), m2->name_and_sig_as_C_string()));
 231         }
 232 #endif //ASSERT
 233       }
 234       if (!m->is_public()) {
 235         assert(m->is_public(), "virtual call must be to public interface method");
 236         return NULL;  // elicit an error later in product build
 237       }
 238       assert(Klass::cast(resolved_klass)->is_subtype_of(m_klass_non_interface()), "virtual call must be type-safe");
 239       m_klass = m_klass_non_interface();
 240     }
 241   }
 242 
 243   oop mname_oop = mname();
 244   java_lang_invoke_MemberName::set_flags(mname_oop,    flags);
 245   java_lang_invoke_MemberName::set_vmtarget(mname_oop, m);
 246   java_lang_invoke_MemberName::set_vmindex(mname_oop,  vmindex);   // vtable/itable index
 247   java_lang_invoke_MemberName::set_clazz(mname_oop,    Klass::cast(m_klass)->java_mirror());
 248   // Note:  name and type can be lazily computed by resolve_MemberName,
 249   // if Java code needs them as resolved String and MethodType objects.
 250   // The clazz must be eagerly stored, because it provides a GC
 251   // root to help keep alive the methodOop.
 252   // If relevant, the vtable or itable value is stored as vmindex.
 253   // This is done eagerly, since it is readily available without
 254   // constructing any new objects.
 255   instanceKlass::cast(m->method_holder())->add_member_name(m->method_idnum(), mname);
 256 
 257   return mname();
 258 }
 259 
 260 Handle MethodHandles::init_method_MemberName(Handle mname, CallInfo& info, TRAPS) {
 261   Handle empty;
 262   if (info.resolved_appendix().not_null()) {
 263     // The resolved MemberName must not be accompanied by an appendix argument,
 264     // since there is no way to bind this value into the MemberName.
 265     // Caller is responsible to prevent this from happening.
 266     THROW_MSG_(vmSymbols::java_lang_InternalError(), "appendix", empty);
 267   }
 268   methodHandle m = info.resolved_method();
 269   KlassHandle defc = info.resolved_klass();
 270   int vmindex = -1;
 271   if (defc->is_interface() && Klass::cast(m->method_holder())->is_interface()) {
 272     // LinkResolver does not report itable indexes!  (fix this?)
 273     vmindex = klassItable::compute_itable_index(m());
 274   } else if (m->can_be_statically_bound()) {
 275     // LinkResolver reports vtable index even for final methods!
 276     vmindex = methodOopDesc::nonvirtual_vtable_index;
 277   } else {
 278     vmindex = info.vtable_index();
 279   }
 280   oop res = init_method_MemberName(mname, m(), (vmindex >= 0), defc());
 281   assert(res == NULL || (java_lang_invoke_MemberName::vmindex(res) == vmindex), "");
 282   return Handle(THREAD, res);
 283 }
 284 
 285 oop MethodHandles::init_field_MemberName(Handle mname, KlassHandle field_holder,
 286                                          AccessFlags mods, oop type, oop name,
 287                                          intptr_t offset, bool is_setter) {
 288   int flags = (jushort)( mods.as_short() & JVM_RECOGNIZED_FIELD_MODIFIERS );
 289   flags |= IS_FIELD | ((mods.is_static() ? JVM_REF_getStatic : JVM_REF_getField) << REFERENCE_KIND_SHIFT);
 290   if (is_setter)  flags += ((JVM_REF_putField - JVM_REF_getField) << REFERENCE_KIND_SHIFT);
 291   oop vmtarget = field_holder();
 292   int vmindex  = offset;  // determines the field uniquely when combined with static bit
 293   oop mname_oop = mname();
 294   java_lang_invoke_MemberName::set_flags(mname_oop,    flags);
 295   java_lang_invoke_MemberName::set_vmtarget(mname_oop, vmtarget);
 296   java_lang_invoke_MemberName::set_vmindex(mname_oop,  vmindex);
 297   java_lang_invoke_MemberName::set_clazz(mname_oop,    field_holder()->java_mirror());
 298   if (name != NULL)
 299     java_lang_invoke_MemberName::set_name(mname_oop,   name);
 300   if (type != NULL)
 301     java_lang_invoke_MemberName::set_type(mname_oop,   type);
 302   // Note:  name and type can be lazily computed by resolve_MemberName,
 303   // if Java code needs them as resolved String and Class objects.
 304   // Note that the incoming type oop might be pre-resolved (non-null).
 305   // The base clazz and field offset (vmindex) must be eagerly stored,
 306   // because they unambiguously identify the field.
 307   // Although the fieldDescriptor::_index would also identify the field,
 308   // we do not use it, because it is harder to decode.
 309   return mname();
 310 }
 311 
 312 Handle MethodHandles::init_field_MemberName(Handle mname, FieldAccessInfo& info, TRAPS) {
 313   return Handle();
 314 #if 0
 315   KlassHandle field_holder = info.klass();
 316   intptr_t    field_offset = info.field_offset();
 317   return init_field_MemberName(mname_oop, field_holder(),
 318                                info.access_flags(),
 319                                type, name,
 320                                field_offset, false /*is_setter*/);
 321 #endif
 322 }
 323 
 324 
 325 // JVM 2.9 Special Methods:
 326 // A method is signature polymorphic if and only if all of the following conditions hold :
 327 // * It is declared in the java.lang.invoke.MethodHandle class.
 328 // * It has a single formal parameter of type Object[].
 329 // * It has a return type of Object.
 330 // * It has the ACC_VARARGS and ACC_NATIVE flags set.
 331 bool MethodHandles::is_method_handle_invoke_name(klassOop klass, Symbol* name) {
 332   if (klass == NULL)
 333     return false;
 334   // The following test will fail spuriously during bootstrap of MethodHandle itself:
 335   //    if (klass != SystemDictionary::MethodHandle_klass())
 336   // Test the name instead:
 337   if (Klass::cast(klass)->name() != vmSymbols::java_lang_invoke_MethodHandle())
 338     return false;
 339   Symbol* poly_sig = vmSymbols::object_array_object_signature();
 340   methodOop m = instanceKlass::cast(klass)->find_method(name, poly_sig);
 341   if (m == NULL)  return false;
 342   int required = JVM_ACC_NATIVE | JVM_ACC_VARARGS;
 343   int flags = m->access_flags().as_int();
 344   return (flags & required) == required;
 345 }
 346 
 347 
 348 Symbol* MethodHandles::signature_polymorphic_intrinsic_name(vmIntrinsics::ID iid) {
 349   assert(is_signature_polymorphic_intrinsic(iid), err_msg("iid=%d", iid));
 350   switch (iid) {
 351   case vmIntrinsics::_invokeBasic:      return vmSymbols::invokeBasic_name();
 352   case vmIntrinsics::_linkToVirtual:    return vmSymbols::linkToVirtual_name();
 353   case vmIntrinsics::_linkToStatic:     return vmSymbols::linkToStatic_name();
 354   case vmIntrinsics::_linkToSpecial:    return vmSymbols::linkToSpecial_name();
 355   case vmIntrinsics::_linkToInterface:  return vmSymbols::linkToInterface_name();
 356   }
 357   assert(false, "");
 358   return 0;
 359 }
 360 
 361 int MethodHandles::signature_polymorphic_intrinsic_ref_kind(vmIntrinsics::ID iid) {
 362   switch (iid) {
 363   case vmIntrinsics::_invokeBasic:      return 0;
 364   case vmIntrinsics::_linkToVirtual:    return JVM_REF_invokeVirtual;
 365   case vmIntrinsics::_linkToStatic:     return JVM_REF_invokeStatic;
 366   case vmIntrinsics::_linkToSpecial:    return JVM_REF_invokeSpecial;
 367   case vmIntrinsics::_linkToInterface:  return JVM_REF_invokeInterface;
 368   }
 369   assert(false, err_msg("iid=%d", iid));
 370   return 0;
 371 }
 372 
 373 vmIntrinsics::ID MethodHandles::signature_polymorphic_name_id(Symbol* name) {
 374   vmSymbols::SID name_id = vmSymbols::find_sid(name);
 375   switch (name_id) {
 376   // The ID _invokeGeneric stands for all non-static signature-polymorphic methods, except built-ins.
 377   case vmSymbols::VM_SYMBOL_ENUM_NAME(invoke_name):           return vmIntrinsics::_invokeGeneric;
 378   // The only built-in non-static signature-polymorphic method is MethodHandle.invokeBasic:
 379   case vmSymbols::VM_SYMBOL_ENUM_NAME(invokeBasic_name):      return vmIntrinsics::_invokeBasic;
 380 
 381   // There is one static signature-polymorphic method for each JVM invocation mode.
 382   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToVirtual_name):    return vmIntrinsics::_linkToVirtual;
 383   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToStatic_name):     return vmIntrinsics::_linkToStatic;
 384   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToSpecial_name):    return vmIntrinsics::_linkToSpecial;
 385   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToInterface_name):  return vmIntrinsics::_linkToInterface;
 386   }
 387 
 388   // Cover the case of invokeExact and any future variants of invokeFoo.
 389   klassOop mh_klass = SystemDictionary::well_known_klass(
 390                               SystemDictionary::WK_KLASS_ENUM_NAME(MethodHandle_klass) );
 391   if (mh_klass != NULL && is_method_handle_invoke_name(mh_klass, name))
 392     return vmIntrinsics::_invokeGeneric;
 393 
 394   // Note: The pseudo-intrinsic _compiledLambdaForm is never linked against.
 395   // Instead it is used to mark lambda forms bound to invokehandle or invokedynamic.
 396   return vmIntrinsics::_none;
 397 }
 398 
 399 vmIntrinsics::ID MethodHandles::signature_polymorphic_name_id(klassOop klass, Symbol* name) {
 400   if (klass != NULL &&
 401       Klass::cast(klass)->name() == vmSymbols::java_lang_invoke_MethodHandle()) {
 402     vmIntrinsics::ID iid = signature_polymorphic_name_id(name);
 403     if (iid != vmIntrinsics::_none)
 404       return iid;
 405     if (is_method_handle_invoke_name(klass, name))
 406       return vmIntrinsics::_invokeGeneric;
 407   }
 408   return vmIntrinsics::_none;
 409 }
 410 
 411 
 412 // convert the external string or reflective type to an internal signature
 413 Symbol* MethodHandles::lookup_signature(oop type_str, bool intern_if_not_found, TRAPS) {
 414   if (java_lang_invoke_MethodType::is_instance(type_str)) {
 415     return java_lang_invoke_MethodType::as_signature(type_str, intern_if_not_found, CHECK_NULL);
 416   } else if (java_lang_Class::is_instance(type_str)) {
 417     return java_lang_Class::as_signature(type_str, false, CHECK_NULL);
 418   } else if (java_lang_String::is_instance(type_str)) {
 419     if (intern_if_not_found) {
 420       return java_lang_String::as_symbol(type_str, CHECK_NULL);
 421     } else {
 422       return java_lang_String::as_symbol_or_null(type_str);
 423     }
 424   } else {
 425     THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized type", NULL);
 426   }
 427 }
 428 
 429 static const char OBJ_SIG[] = "Ljava/lang/Object;";
 430 enum { OBJ_SIG_LEN = 18 };
 431 
 432 bool MethodHandles::is_basic_type_signature(Symbol* sig) {
 433   assert(vmSymbols::object_signature()->utf8_length() == (int)OBJ_SIG_LEN, "");
 434   assert(vmSymbols::object_signature()->equals(OBJ_SIG), "");
 435   const int len = sig->utf8_length();
 436   for (int i = 0; i < len; i++) {
 437     switch (sig->byte_at(i)) {
 438     case 'L':
 439       // only java/lang/Object is valid here
 440       if (sig->index_of_at(i, OBJ_SIG, OBJ_SIG_LEN) != i)
 441         return false;
 442       i += OBJ_SIG_LEN-1;  //-1 because of i++ in loop
 443       continue;
 444     case '(': case ')': case 'V':
 445     case 'I': case 'J': case 'F': case 'D':
 446       continue;
 447     //case '[':
 448     //case 'Z': case 'B': case 'C': case 'S':
 449     default:
 450       return false;
 451     }
 452   }
 453   return true;
 454 }
 455 
 456 Symbol* MethodHandles::lookup_basic_type_signature(Symbol* sig, bool keep_last_arg, TRAPS) {
 457   Symbol* bsig = NULL;
 458   if (sig == NULL) {
 459     return sig;
 460   } else if (is_basic_type_signature(sig)) {
 461     sig->increment_refcount();
 462     return sig;  // that was easy
 463   } else if (sig->byte_at(0) != '(') {
 464     BasicType bt = char2type(sig->byte_at(0));
 465     if (is_subword_type(bt)) {
 466       bsig = vmSymbols::int_signature();
 467     } else {
 468       assert(bt == T_OBJECT || bt == T_ARRAY, "is_basic_type_signature was false");
 469       bsig = vmSymbols::object_signature();
 470     }
 471   } else {
 472     ResourceMark rm;
 473     stringStream buffer(128);
 474     buffer.put('(');
 475     int arg_pos = 0, keep_arg_pos = -1;
 476     if (keep_last_arg)
 477       keep_arg_pos = ArgumentCount(sig).size() - 1;
 478     for (SignatureStream ss(sig); !ss.is_done(); ss.next()) {
 479       BasicType bt = ss.type();
 480       size_t this_arg_pos = buffer.size();
 481       if (ss.at_return_type()) {
 482         buffer.put(')');
 483       }
 484       if (arg_pos == keep_arg_pos) {
 485         buffer.write((char*) ss.raw_bytes(),
 486                      (int)   ss.raw_length());
 487       } else if (bt == T_OBJECT || bt == T_ARRAY) {
 488         buffer.write(OBJ_SIG, OBJ_SIG_LEN);
 489       } else {
 490         if (is_subword_type(bt))
 491           bt = T_INT;
 492         buffer.put(type2char(bt));
 493       }
 494       arg_pos++;
 495     }
 496     const char* sigstr =       buffer.base();
 497     int         siglen = (int) buffer.size();
 498     bsig = SymbolTable::new_symbol(sigstr, siglen, THREAD);
 499   }
 500   assert(is_basic_type_signature(bsig) ||
 501          // detune assert in case the injected argument is not a basic type:
 502          keep_last_arg, "");
 503   return bsig;
 504 }
 505 
 506 void MethodHandles::print_as_basic_type_signature_on(outputStream* st,
 507                                                      Symbol* sig,
 508                                                      bool keep_arrays,
 509                                                      bool keep_basic_names) {
 510   st = st ? st : tty;
 511   int len  = sig->utf8_length();
 512   int array = 0;
 513   bool prev_type = false;
 514   for (int i = 0; i < len; i++) {
 515     char ch = sig->byte_at(i);
 516     switch (ch) {
 517     case '(': case ')':
 518       prev_type = false;
 519       st->put(ch);
 520       continue;
 521     case '[':
 522       if (!keep_basic_names && keep_arrays)
 523         st->put(ch);
 524       array++;
 525       continue;
 526     case 'L':
 527       {
 528         if (prev_type)  st->put(',');
 529         int start = i+1, slash = start;
 530         while (++i < len && (ch = sig->byte_at(i)) != ';') {
 531           if (ch == '/' || ch == '.' || ch == '$')  slash = i+1;
 532         }
 533         if (slash < i)  start = slash;
 534         if (!keep_basic_names) {
 535           st->put('L');
 536         } else {
 537           for (int j = start; j < i; j++)
 538             st->put(sig->byte_at(j));
 539           prev_type = true;
 540         }
 541         break;
 542       }
 543     default:
 544       {
 545         if (array && char2type(ch) != T_ILLEGAL && !keep_arrays) {
 546           ch = '[';
 547           array = 0;
 548         }
 549         if (prev_type)  st->put(',');
 550         const char* n = NULL;
 551         if (keep_basic_names)
 552           n = type2name(char2type(ch));
 553         if (n == NULL) {
 554           // unknown letter, or we don't want to know its name
 555           st->put(ch);
 556         } else {
 557           st->print(n);
 558           prev_type = true;
 559         }
 560         break;
 561       }
 562     }
 563     // Switch break goes here to take care of array suffix:
 564     if (prev_type) {
 565       while (array > 0) {
 566         st->print("[]");
 567         --array;
 568       }
 569     }
 570     array = 0;
 571   }
 572 }
 573 
 574 
 575 
 576 static oop object_java_mirror() {
 577   return Klass::cast(SystemDictionary::Object_klass())->java_mirror();
 578 }
 579 
 580 static oop field_name_or_null(Symbol* s) {
 581   if (s == NULL)  return NULL;
 582   return StringTable::lookup(s);
 583 }
 584 
 585 static oop field_signature_type_or_null(Symbol* s) {
 586   if (s == NULL)  return NULL;
 587   BasicType bt = FieldType::basic_type(s);
 588   if (is_java_primitive(bt)) {
 589     assert(s->utf8_length() == 1, "");
 590     return java_lang_Class::primitive_mirror(bt);
 591   }
 592   // Here are some more short cuts for common types.
 593   // They are optional, since reference types can be resolved lazily.
 594   if (bt == T_OBJECT) {
 595     if (s == vmSymbols::object_signature()) {
 596       return object_java_mirror();
 597     } else if (s == vmSymbols::class_signature()) {
 598       return Klass::cast(SystemDictionary::Class_klass())->java_mirror();
 599     } else if (s == vmSymbols::string_signature()) {
 600       return Klass::cast(SystemDictionary::String_klass())->java_mirror();
 601     }
 602   }
 603   return NULL;
 604 }
 605 
 606 // An unresolved member name is a mere symbolic reference.
 607 // Resolving it plants a vmtarget/vmindex in it,
 608 // which refers dirctly to JVM internals.
 609 Handle MethodHandles::resolve_MemberName(Handle mname, KlassHandle caller, TRAPS) {
 610   Handle empty;
 611   assert(java_lang_invoke_MemberName::is_instance(mname()), "");
 612 
 613   if (java_lang_invoke_MemberName::vmtarget(mname()) != NULL) {
 614     // Already resolved.
 615     DEBUG_ONLY(int vmindex = java_lang_invoke_MemberName::vmindex(mname()));
 616     assert(vmindex >= methodOopDesc::nonvirtual_vtable_index, "");
 617     return mname;
 618   }
 619 
 620   Handle defc_oop(THREAD, java_lang_invoke_MemberName::clazz(mname()));
 621   Handle name_str(THREAD, java_lang_invoke_MemberName::name( mname()));
 622   Handle type_str(THREAD, java_lang_invoke_MemberName::type( mname()));
 623   int    flags    =       java_lang_invoke_MemberName::flags(mname());
 624   int    ref_kind =       (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
 625   if (!ref_kind_is_valid(ref_kind)) {
 626     THROW_MSG_(vmSymbols::java_lang_InternalError(), "obsolete MemberName format", empty);
 627   }
 628 
 629   DEBUG_ONLY(int old_vmindex);
 630   assert((old_vmindex = java_lang_invoke_MemberName::vmindex(mname())) == 0, "clean input");
 631 
 632   if (defc_oop.is_null() || name_str.is_null() || type_str.is_null()) {
 633     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(), "nothing to resolve", empty);
 634   }
 635 
 636   instanceKlassHandle defc;
 637   {
 638     klassOop defc_klassOop = java_lang_Class::as_klassOop(defc_oop());
 639     if (defc_klassOop == NULL)  return empty;  // a primitive; no resolution possible
 640     if (!Klass::cast(defc_klassOop)->oop_is_instance()) {
 641       if (!Klass::cast(defc_klassOop)->oop_is_array())  return empty;
 642       defc_klassOop = SystemDictionary::Object_klass();
 643     }
 644     defc = instanceKlassHandle(THREAD, defc_klassOop);
 645   }
 646   if (defc.is_null()) {
 647     THROW_MSG_(vmSymbols::java_lang_InternalError(), "primitive class", empty);
 648   }
 649   defc->link_class(CHECK_(empty));  // possible safepoint
 650 
 651   // convert the external string name to an internal symbol
 652   TempNewSymbol name = java_lang_String::as_symbol_or_null(name_str());
 653   if (name == NULL)  return empty;  // no such name
 654   if (name == vmSymbols::class_initializer_name())
 655     return empty; // illegal name
 656 
 657   vmIntrinsics::ID mh_invoke_id = vmIntrinsics::_none;
 658   if ((flags & ALL_KINDS) == IS_METHOD &&
 659       (defc() == SystemDictionary::MethodHandle_klass()) &&
 660       (ref_kind == JVM_REF_invokeVirtual ||
 661        ref_kind == JVM_REF_invokeSpecial ||
 662        // static invocation mode is required for _linkToVirtual, etc.:
 663        ref_kind == JVM_REF_invokeStatic)) {
 664     vmIntrinsics::ID iid = signature_polymorphic_name_id(name);
 665     if (iid != vmIntrinsics::_none &&
 666         ((ref_kind == JVM_REF_invokeStatic) == is_signature_polymorphic_static(iid))) {
 667       // Virtual methods invoke and invokeExact, plus internal invokers like _invokeBasic.
 668       // For a static reference it could an internal linkage routine like _linkToVirtual, etc.
 669       mh_invoke_id = iid;
 670     }
 671   }
 672 
 673   // convert the external string or reflective type to an internal signature
 674   TempNewSymbol type = lookup_signature(type_str(), (mh_invoke_id != vmIntrinsics::_none), CHECK_(empty));
 675   if (type == NULL)  return empty;  // no such signature exists in the VM
 676 
 677   // Time to do the lookup.
 678   switch (flags & ALL_KINDS) {
 679   case IS_METHOD:
 680     {
 681       CallInfo result;
 682       bool do_dispatch = true;  // default, neutral setting
 683       {
 684         assert(!HAS_PENDING_EXCEPTION, "");
 685         if (ref_kind == JVM_REF_invokeStatic) {
 686           //do_dispatch = false;  // no need, since statics are never dispatched
 687           LinkResolver::resolve_static_call(result,
 688                         defc, name, type, caller, caller.not_null(), false, THREAD);
 689         } else if (ref_kind == JVM_REF_invokeInterface) {
 690           LinkResolver::resolve_interface_call(result, Handle(), defc,
 691                         defc, name, type, caller, caller.not_null(), false, THREAD);
 692         } else if (mh_invoke_id != vmIntrinsics::_none) {
 693           assert(!is_signature_polymorphic_static(mh_invoke_id), "");
 694           LinkResolver::resolve_handle_call(result,
 695                         defc, name, type, caller, THREAD);
 696         } else if (ref_kind == JVM_REF_invokeSpecial) {
 697           do_dispatch = false;  // force non-virtual linkage
 698           LinkResolver::resolve_special_call(result,
 699                         defc, name, type, caller, caller.not_null(), THREAD);
 700           // CR 8029533:
 701           // As a corner case, invokespecial can return a method *below* its resolved_klass.
 702           // Since method search *starts* at the resolved_klass, the eventual
 703           // method is almost always in a supertype *above* the resolved_klass.
 704           // This pattern breaks when an invokespecial "over-reaches" beyond an
 705           // immediate super to a method overridden by a super class.
 706           // In that case, the selected method will be below the resolved_klass.
 707           // (This is the behavior enabled by the famous ACC_SUPER classfile flag.)
 708           //
 709           // Downstream of this code, we make assumptions about resolved_klass being below m.
 710           // (See init_method_MemberName, the comment "bad receiver limit".)
 711           // We basically want to patch result._resolved_klass to be m.method_holder().
 712           // The simplest way to get this happier outcome is to re-resolve.
 713           if (!HAS_PENDING_EXCEPTION &&
 714               caller.not_null() &&
 715               result.resolved_method().not_null()) {
 716             // this is the m_klass value that will be checked later:
 717             klassOop m_klass = result.resolved_method()->method_holder();
 718             if (m_klass != result.resolved_klass()() &&
 719                 Klass::cast(m_klass)->is_subtype_of(result.resolved_klass()())) {
 720               KlassHandle adjusted_defc(THREAD, m_klass);
 721               LinkResolver::resolve_special_call(result,
 722                             adjusted_defc, name, type, caller, caller.not_null(), THREAD);
 723               assert(HAS_PENDING_EXCEPTION  // if there is something like an OOM, pass it up to caller
 724                      || result.resolved_method()->method_holder() == adjusted_defc(),
 725                      "same method, different resolved_klass");
 726             }
 727           }
 728         } else if (ref_kind == JVM_REF_invokeVirtual) {
 729           LinkResolver::resolve_virtual_call(result, Handle(), defc,
 730                         defc, name, type, caller, caller.not_null(), false, THREAD);
 731         } else {
 732           assert(false, err_msg("ref_kind=%d", ref_kind));
 733         }
 734         if (HAS_PENDING_EXCEPTION) {
 735           return empty;
 736         }
 737       }
 738       return init_method_MemberName(mname, result, THREAD);
 739     }
 740   case IS_CONSTRUCTOR:
 741     {
 742       CallInfo result;
 743       {
 744         assert(!HAS_PENDING_EXCEPTION, "");
 745         if (name == vmSymbols::object_initializer_name()) {
 746           LinkResolver::resolve_special_call(result,
 747                         defc, name, type, caller, caller.not_null(), THREAD);
 748         } else {
 749           break;                // will throw after end of switch
 750         }
 751         if (HAS_PENDING_EXCEPTION) {
 752           return empty;
 753         }
 754       }
 755       assert(result.is_statically_bound(), "");
 756       return init_method_MemberName(mname, result, THREAD);
 757     }
 758   case IS_FIELD:
 759     {
 760       // This is taken from LinkResolver::resolve_field, sans access checks.
 761       fieldDescriptor fd; // find_field initializes fd if found
 762       KlassHandle sel_klass(THREAD, instanceKlass::cast(defc())->find_field(name, type, &fd));
 763       // check if field exists; i.e., if a klass containing the field def has been selected
 764       if (sel_klass.is_null())  return empty;  // should not happen
 765       oop type = field_signature_type_or_null(fd.signature());
 766       oop name = field_name_or_null(fd.name());
 767       bool is_setter = (ref_kind_is_valid(ref_kind) && ref_kind_is_setter(ref_kind));
 768       mname = Handle(THREAD,
 769                      init_field_MemberName(mname, sel_klass,
 770                                            fd.access_flags(), type, name, fd.offset(), is_setter));
 771       return mname;
 772     }
 773   default:
 774     THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format", empty);
 775   }
 776 
 777   return empty;
 778 }
 779 
 780 // Conversely, a member name which is only initialized from JVM internals
 781 // may have null defc, name, and type fields.
 782 // Resolving it plants a vmtarget/vmindex in it,
 783 // which refers directly to JVM internals.
 784 void MethodHandles::expand_MemberName(Handle mname, int suppress, TRAPS) {
 785   assert(java_lang_invoke_MemberName::is_instance(mname()), "");
 786   oop vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
 787   int vmindex  = java_lang_invoke_MemberName::vmindex(mname());
 788   if (vmtarget == NULL) {
 789     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "nothing to expand");
 790   }
 791 
 792   bool have_defc = (java_lang_invoke_MemberName::clazz(mname()) != NULL);
 793   bool have_name = (java_lang_invoke_MemberName::name(mname()) != NULL);
 794   bool have_type = (java_lang_invoke_MemberName::type(mname()) != NULL);
 795   int flags      = java_lang_invoke_MemberName::flags(mname());
 796 
 797   if (suppress != 0) {
 798     if (suppress & _suppress_defc)  have_defc = true;
 799     if (suppress & _suppress_name)  have_name = true;
 800     if (suppress & _suppress_type)  have_type = true;
 801   }
 802 
 803   if (have_defc && have_name && have_type)  return;  // nothing needed
 804 
 805   switch (flags & ALL_KINDS) {
 806   case IS_METHOD:
 807   case IS_CONSTRUCTOR:
 808     {
 809       assert(vmtarget->is_method(), "method or constructor vmtarget is methodOop");
 810       methodHandle m(THREAD, methodOop(vmtarget));
 811       DEBUG_ONLY(vmtarget = NULL);  // safety
 812       if (m.is_null())  break;
 813       if (!have_defc) {
 814         klassOop defc = m->method_holder();
 815         java_lang_invoke_MemberName::set_clazz(mname(), Klass::cast(defc)->java_mirror());
 816       }
 817       if (!have_name) {
 818         //not java_lang_String::create_from_symbol; let's intern member names
 819         Handle name = StringTable::intern(m->name(), CHECK);
 820         java_lang_invoke_MemberName::set_name(mname(), name());
 821       }
 822       if (!have_type) {
 823         Handle type = java_lang_String::create_from_symbol(m->signature(), CHECK);
 824         java_lang_invoke_MemberName::set_type(mname(), type());
 825       }
 826       return;
 827     }
 828   case IS_FIELD:
 829     {
 830       // This is taken from LinkResolver::resolve_field, sans access checks.
 831       assert(vmtarget->is_klass(), "field vmtarget is klassOop");
 832       if (!Klass::cast((klassOop) vmtarget)->oop_is_instance())  break;
 833       instanceKlassHandle defc(THREAD, (klassOop) vmtarget);
 834       DEBUG_ONLY(vmtarget = NULL);  // safety
 835       bool is_static = ((flags & JVM_ACC_STATIC) != 0);
 836       fieldDescriptor fd; // find_field initializes fd if found
 837       if (!defc->find_field_from_offset(vmindex, is_static, &fd))
 838         break;                  // cannot expand
 839       if (!have_defc) {
 840         java_lang_invoke_MemberName::set_clazz(mname(), defc->java_mirror());
 841       }
 842       if (!have_name) {
 843         //not java_lang_String::create_from_symbol; let's intern member names
 844         Handle name = StringTable::intern(fd.name(), CHECK);
 845         java_lang_invoke_MemberName::set_name(mname(), name());
 846       }
 847       if (!have_type) {
 848         // If it is a primitive field type, don't mess with short strings like "I".
 849         Handle type = field_signature_type_or_null(fd.signature());
 850         if (type.is_null()) {
 851           java_lang_String::create_from_symbol(fd.signature(), CHECK);
 852         }
 853         java_lang_invoke_MemberName::set_type(mname(), type());
 854       }
 855       return;
 856     }
 857   }
 858   THROW_MSG(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format");
 859 }
 860 
 861 int MethodHandles::find_MemberNames(KlassHandle k,
 862                                     Symbol* name, Symbol* sig,
 863                                     int mflags, KlassHandle caller,
 864                                     int skip, objArrayHandle results) {
 865 
 866   // %%% take caller into account!
 867 
 868   Thread* thread = Thread::current();
 869 
 870   if (k.is_null() || !k->oop_is_instance())  return -1;
 871 
 872   int rfill = 0, rlimit = results->length(), rskip = skip;
 873   // overflow measurement:
 874   int overflow = 0, overflow_limit = MAX2(1000, rlimit);
 875 
 876   int match_flags = mflags;
 877   bool search_superc = ((match_flags & SEARCH_SUPERCLASSES) != 0);
 878   bool search_intfc  = ((match_flags & SEARCH_INTERFACES)   != 0);
 879   bool local_only = !(search_superc | search_intfc);
 880   bool classes_only = false;
 881 
 882   if (name != NULL) {
 883     if (name->utf8_length() == 0)  return 0; // a match is not possible
 884   }
 885   if (sig != NULL) {
 886     if (sig->utf8_length() == 0)  return 0; // a match is not possible
 887     if (sig->byte_at(0) == '(')
 888       match_flags &= ~(IS_FIELD | IS_TYPE);
 889     else
 890       match_flags &= ~(IS_CONSTRUCTOR | IS_METHOD);
 891   }
 892 
 893   if ((match_flags & IS_TYPE) != 0) {
 894     // NYI, and Core Reflection works quite well for this query
 895   }
 896 
 897   if ((match_flags & IS_FIELD) != 0) {
 898     for (FieldStream st(k(), local_only, !search_intfc); !st.eos(); st.next()) {
 899       if (name != NULL && st.name() != name)
 900           continue;
 901       if (sig != NULL && st.signature() != sig)
 902         continue;
 903       // passed the filters
 904       if (rskip > 0) {
 905         --rskip;
 906       } else if (rfill < rlimit) {
 907         Handle result(thread, results->obj_at(rfill++));
 908         if (!java_lang_invoke_MemberName::is_instance(result()))
 909           return -99;  // caller bug!
 910         oop type = field_signature_type_or_null(st.signature());
 911         oop name = field_name_or_null(st.name());
 912         oop saved = MethodHandles::init_field_MemberName(result, st.klass(),
 913                                                          st.access_flags(), type, name,
 914                                                          st.offset());
 915         if (saved != result())
 916           results->obj_at_put(rfill-1, saved);  // show saved instance to user
 917       } else if (++overflow >= overflow_limit) {
 918         match_flags = 0; break; // got tired of looking at overflow
 919       }
 920     }
 921   }
 922 
 923   if ((match_flags & (IS_METHOD | IS_CONSTRUCTOR)) != 0) {
 924     // watch out for these guys:
 925     Symbol* init_name   = vmSymbols::object_initializer_name();
 926     Symbol* clinit_name = vmSymbols::class_initializer_name();
 927     if (name == clinit_name)  clinit_name = NULL; // hack for exposing <clinit>
 928     bool negate_name_test = false;
 929     // fix name so that it captures the intention of IS_CONSTRUCTOR
 930     if (!(match_flags & IS_METHOD)) {
 931       // constructors only
 932       if (name == NULL) {
 933         name = init_name;
 934       } else if (name != init_name) {
 935         return 0;               // no constructors of this method name
 936       }
 937     } else if (!(match_flags & IS_CONSTRUCTOR)) {
 938       // methods only
 939       if (name == NULL) {
 940         name = init_name;
 941         negate_name_test = true; // if we see the name, we *omit* the entry
 942       } else if (name == init_name) {
 943         return 0;               // no methods of this constructor name
 944       }
 945     } else {
 946       // caller will accept either sort; no need to adjust name
 947     }
 948     for (MethodStream st(k(), local_only, !search_intfc); !st.eos(); st.next()) {
 949       methodOop m = st.method();
 950       Symbol* m_name = m->name();
 951       if (m_name == clinit_name)
 952         continue;
 953       if (name != NULL && ((m_name != name) ^ negate_name_test))
 954           continue;
 955       if (sig != NULL && m->signature() != sig)
 956         continue;
 957       // passed the filters
 958       if (rskip > 0) {
 959         --rskip;
 960       } else if (rfill < rlimit) {
 961         Handle result(thread, results->obj_at(rfill++));
 962         if (!java_lang_invoke_MemberName::is_instance(result()))
 963           return -99;  // caller bug!
 964         oop saved = MethodHandles::init_method_MemberName(result, m, true, KlassHandle());
 965         if (saved != result())
 966           results->obj_at_put(rfill-1, saved);  // show saved instance to user
 967       } else if (++overflow >= overflow_limit) {
 968         match_flags = 0; break; // got tired of looking at overflow
 969       }
 970     }
 971   }
 972 
 973   // return number of elements we at leasted wanted to initialize
 974   return rfill + overflow;
 975 }
 976 
 977 //------------------------------------------------------------------------------
 978 // MemberNameTable
 979 //
 980 
 981 MemberNameTable::MemberNameTable(int methods_cnt)
 982                   : GrowableArray<jweak>(methods_cnt, true) {
 983   assert_locked_or_safepoint(MemberNameTable_lock);
 984 }
 985 
 986 MemberNameTable::~MemberNameTable() {
 987   assert_locked_or_safepoint(MemberNameTable_lock);
 988   int len = this->length();
 989 
 990   for (int idx = 0; idx < len; idx++) {
 991     jweak ref = this->at(idx);
 992     JNIHandles::destroy_weak_global(ref);
 993   }
 994 }
 995 
 996 void MemberNameTable::add_member_name(int index, jweak mem_name_wref) {
 997   assert_locked_or_safepoint(MemberNameTable_lock);
 998   this->at_put_grow(index, mem_name_wref);
 999 }
1000 
1001 // Return a member name oop or NULL.
1002 oop MemberNameTable::get_member_name(int index) {
1003   assert_locked_or_safepoint(MemberNameTable_lock);
1004   jweak ref = this->at(index);
1005   oop mem_name = JNIHandles::resolve(ref);
1006   return mem_name;
1007 }
1008 
1009 oop MemberNameTable::find_member_name_by_method(methodOop old_method) {
1010   assert_locked_or_safepoint(MemberNameTable_lock);
1011   oop found = NULL;
1012   int len = this->length();
1013 
1014   for (int idx = 0; idx < len; idx++) {
1015     oop mem_name = JNIHandles::resolve(this->at(idx));
1016     if (mem_name == NULL) {
1017       continue;
1018     }
1019     methodOop method = (methodOop)java_lang_invoke_MemberName::vmtarget(mem_name);
1020     if (method == old_method) {
1021       found = mem_name;
1022       break;
1023     }
1024   }
1025   return found;
1026 }
1027 
1028 // It is called at safepoint only
1029 void MemberNameTable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
1030                                             int methods_length, bool *trace_name_printed) {
1031   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
1032   // search the MemberNameTable for uses of either obsolete or EMCP methods
1033   for (int j = 0; j < methods_length; j++) {
1034     methodOop old_method = old_methods[j];
1035     methodOop new_method = new_methods[j];
1036     oop mem_name = find_member_name_by_method(old_method);
1037     if (mem_name != NULL) {
1038       java_lang_invoke_MemberName::adjust_vmtarget(mem_name, new_method);
1039 
1040       if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
1041         if (!(*trace_name_printed)) {
1042           // RC_TRACE_MESG macro has an embedded ResourceMark
1043           RC_TRACE_MESG(("adjust: name=%s",
1044                          Klass::cast(old_method->method_holder())->external_name()));
1045           *trace_name_printed = true;
1046         }
1047         // RC_TRACE macro has an embedded ResourceMark
1048         RC_TRACE(0x00400000, ("MemberName method update: %s(%s)",
1049                               new_method->name()->as_C_string(),
1050                               new_method->signature()->as_C_string()));
1051       }
1052     }
1053   }
1054 }
1055 
1056 //
1057 // Here are the native methods in java.lang.invoke.MethodHandleNatives
1058 // They are the private interface between this JVM and the HotSpot-specific
1059 // Java code that implements JSR 292 method handles.
1060 //
1061 // Note:  We use a JVM_ENTRY macro to define each of these, for this is the way
1062 // that intrinsic (non-JNI) native methods are defined in HotSpot.
1063 //
1064 JVM_ENTRY(jint, MHN_getConstant(JNIEnv *env, jobject igcls, jint which)) {
1065   switch (which) {
1066   case MethodHandles::GC_COUNT_GWT:
1067 #ifdef COMPILER2
1068     return true;
1069 #else
1070     return false;
1071 #endif
1072   }
1073   return 0;
1074 }
1075 JVM_END
1076 
1077 #ifndef PRODUCT
1078 #define EACH_NAMED_CON(template, requirement) \
1079     template(MethodHandles,GC_COUNT_GWT) \
1080     template(java_lang_invoke_MemberName,MN_IS_METHOD) \
1081     template(java_lang_invoke_MemberName,MN_IS_CONSTRUCTOR) \
1082     template(java_lang_invoke_MemberName,MN_IS_FIELD) \
1083     template(java_lang_invoke_MemberName,MN_IS_TYPE) \
1084     template(java_lang_invoke_MemberName,MN_SEARCH_SUPERCLASSES) \
1085     template(java_lang_invoke_MemberName,MN_SEARCH_INTERFACES) \
1086     template(java_lang_invoke_MemberName,MN_REFERENCE_KIND_SHIFT) \
1087     template(java_lang_invoke_MemberName,MN_REFERENCE_KIND_MASK) \
1088     template(MethodHandles,GC_LAMBDA_SUPPORT) \
1089     /*end*/
1090 
1091 #define IGNORE_REQ(req_expr) /* req_expr */
1092 #define ONE_PLUS(scope,value) 1+
1093 static const int con_value_count = EACH_NAMED_CON(ONE_PLUS, IGNORE_REQ) 0;
1094 #define VALUE_COMMA(scope,value) scope::value,
1095 static const int con_values[con_value_count+1] = { EACH_NAMED_CON(VALUE_COMMA, IGNORE_REQ) 0 };
1096 #define STRING_NULL(scope,value) #value "\0"
1097 static const char con_names[] = { EACH_NAMED_CON(STRING_NULL, IGNORE_REQ) };
1098 
1099 static bool advertise_con_value(int which) {
1100   if (which < 0)  return false;
1101   bool ok = true;
1102   int count = 0;
1103 #define INC_COUNT(scope,value) \
1104   ++count;
1105 #define CHECK_REQ(req_expr) \
1106   if (which < count)  return ok; \
1107   ok = (req_expr);
1108   EACH_NAMED_CON(INC_COUNT, CHECK_REQ);
1109 #undef INC_COUNT
1110 #undef CHECK_REQ
1111   assert(count == con_value_count, "");
1112   if (which < count)  return ok;
1113   return false;
1114 }
1115 
1116 #undef ONE_PLUS
1117 #undef VALUE_COMMA
1118 #undef STRING_NULL
1119 #undef EACH_NAMED_CON
1120 #endif // PRODUCT
1121 
1122 JVM_ENTRY(jint, MHN_getNamedCon(JNIEnv *env, jobject igcls, jint which, jobjectArray box_jh)) {
1123 #ifndef PRODUCT
1124   if (advertise_con_value(which)) {
1125     assert(which >= 0 && which < con_value_count, "");
1126     int con = con_values[which];
1127     objArrayHandle box(THREAD, (objArrayOop) JNIHandles::resolve(box_jh));
1128     if (box.not_null() && box->klass() == Universe::objectArrayKlassObj() && box->length() > 0) {
1129       const char* str = &con_names[0];
1130       for (int i = 0; i < which; i++)
1131         str += strlen(str) + 1;   // skip name and null
1132       oop name = java_lang_String::create_oop_from_str(str, CHECK_0);  // possible safepoint
1133       box->obj_at_put(0, name);
1134     }
1135     return con;
1136   }
1137 #endif
1138   return 0;
1139 }
1140 JVM_END
1141 
1142 // void init(MemberName self, AccessibleObject ref)
1143 JVM_ENTRY(void, MHN_init_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jobject target_jh)) {
1144   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
1145   if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
1146   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1147   Handle target(THREAD, JNIHandles::resolve_non_null(target_jh));
1148   MethodHandles::init_MemberName(mname, target);
1149 }
1150 JVM_END
1151 
1152 // void expand(MemberName self)
1153 JVM_ENTRY(void, MHN_expand_Mem(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1154   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
1155   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1156   MethodHandles::expand_MemberName(mname, 0, CHECK);
1157 }
1158 JVM_END
1159 
1160 // void resolve(MemberName self, Class<?> caller)
1161 JVM_ENTRY(jobject, MHN_resolve_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jclass caller_jh)) {
1162   if (mname_jh == NULL) { THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "mname is null"); }
1163   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1164 
1165   // The trusted Java code that calls this method should already have performed
1166   // access checks on behalf of the given caller.  But, we can verify this.
1167   if (VerifyMethodHandles && caller_jh != NULL &&
1168       java_lang_invoke_MemberName::clazz(mname()) != NULL) {
1169     klassOop reference_klass = java_lang_Class::as_klassOop(java_lang_invoke_MemberName::clazz(mname()));
1170     if (reference_klass != NULL && Klass::cast(reference_klass)->oop_is_objArray()) {
1171       reference_klass = objArrayKlass::cast(reference_klass)->bottom_klass();
1172     }
1173 
1174     // Reflection::verify_class_access can only handle instance classes.
1175     if (reference_klass != NULL && Klass::cast(reference_klass)->oop_is_instance()) {
1176       // Emulate LinkResolver::check_klass_accessability.
1177       klassOop caller = java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(caller_jh));
1178       if (!Reflection::verify_class_access(caller,
1179                                            reference_klass,
1180                                            true)) {
1181         THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), Klass::cast(reference_klass)->external_name());
1182       }
1183     }
1184   }
1185 
1186   KlassHandle caller(THREAD,
1187                      caller_jh == NULL ? (klassOop) NULL :
1188                      java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(caller_jh)));
1189   Handle resolved = MethodHandles::resolve_MemberName(mname, caller, CHECK_NULL);
1190 
1191   if (resolved.is_null()) {
1192     int flags = java_lang_invoke_MemberName::flags(mname());
1193     int ref_kind = (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
1194     if (!MethodHandles::ref_kind_is_valid(ref_kind)) {
1195       THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "obsolete MemberName format");
1196     }
1197     if ((flags & ALL_KINDS) == IS_FIELD) {
1198       THROW_MSG_NULL(vmSymbols::java_lang_NoSuchMethodError(), "field resolution failed");
1199     } else if ((flags & ALL_KINDS) == IS_METHOD ||
1200                (flags & ALL_KINDS) == IS_CONSTRUCTOR) {
1201       THROW_MSG_NULL(vmSymbols::java_lang_NoSuchFieldError(), "method resolution failed");
1202     } else {
1203       THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "resolution failed");
1204     }
1205   }
1206 
1207   return JNIHandles::make_local(THREAD, resolved());
1208 }
1209 JVM_END
1210 
1211 static jlong find_member_field_offset(oop mname, bool must_be_static, TRAPS) {
1212   if (mname == NULL ||
1213       java_lang_invoke_MemberName::vmtarget(mname) == NULL) {
1214     THROW_MSG_0(vmSymbols::java_lang_InternalError(), "mname not resolved");
1215   } else {
1216     int flags = java_lang_invoke_MemberName::flags(mname);
1217     if ((flags & IS_FIELD) != 0 &&
1218         (must_be_static
1219          ? (flags & JVM_ACC_STATIC) != 0
1220          : (flags & JVM_ACC_STATIC) == 0)) {
1221       int vmindex = java_lang_invoke_MemberName::vmindex(mname);
1222       return (jlong) vmindex;
1223     }
1224   }
1225   const char* msg = (must_be_static ? "static field required" : "non-static field required");
1226   THROW_MSG_0(vmSymbols::java_lang_InternalError(), msg);
1227   return 0;
1228 }
1229 
1230 JVM_ENTRY(jlong, MHN_objectFieldOffset(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1231   return find_member_field_offset(JNIHandles::resolve(mname_jh), false, THREAD);
1232 }
1233 JVM_END
1234 
1235 JVM_ENTRY(jlong, MHN_staticFieldOffset(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1236   return find_member_field_offset(JNIHandles::resolve(mname_jh), true, THREAD);
1237 }
1238 JVM_END
1239 
1240 JVM_ENTRY(jobject, MHN_staticFieldBase(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1241   // use the other function to perform sanity checks:
1242   jlong ignore = find_member_field_offset(JNIHandles::resolve(mname_jh), true, CHECK_NULL);
1243   oop clazz = java_lang_invoke_MemberName::clazz(JNIHandles::resolve_non_null(mname_jh));
1244   return JNIHandles::make_local(THREAD, clazz);
1245 }
1246 JVM_END
1247 
1248 JVM_ENTRY(jobject, MHN_getMemberVMInfo(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1249   if (mname_jh == NULL)  return NULL;
1250   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1251   intptr_t vmindex  = java_lang_invoke_MemberName::vmindex(mname());
1252   Handle   vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
1253   objArrayHandle result = oopFactory::new_objArray(SystemDictionary::Object_klass(), 2, CHECK_NULL);
1254   jvalue vmindex_value; vmindex_value.j = (long)vmindex;
1255   oop x = java_lang_boxing_object::create(T_LONG, &vmindex_value, CHECK_NULL);
1256   result->obj_at_put(0, x);
1257   x = NULL;
1258   if (vmtarget.is_null() || vmtarget->is_instance()) {
1259     x = vmtarget();
1260   } else if (vmtarget->is_klass()) {
1261     x = Klass::cast((klassOop) vmtarget())->java_mirror();
1262   } else {
1263     if (vmtarget->is_method()) {
1264       x = mname();
1265     } else {
1266       Handle mname2 = MethodHandles::new_MemberName(CHECK_NULL);
1267       x = MethodHandles::init_MemberName(mname2(), vmtarget());
1268     }
1269   }
1270   result->obj_at_put(1, x);
1271   return JNIHandles::make_local(env, result());
1272 }
1273 JVM_END
1274 
1275 
1276 
1277 //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
1278 //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
1279 JVM_ENTRY(jint, MHN_getMembers(JNIEnv *env, jobject igcls,
1280                                jclass clazz_jh, jstring name_jh, jstring sig_jh,
1281                                int mflags, jclass caller_jh, jint skip, jobjectArray results_jh)) {
1282   if (clazz_jh == NULL || results_jh == NULL)  return -1;
1283   KlassHandle k(THREAD, java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(clazz_jh)));
1284 
1285   objArrayHandle results(THREAD, (objArrayOop) JNIHandles::resolve(results_jh));
1286   if (results.is_null() || !results->is_objArray())  return -1;
1287 
1288   TempNewSymbol name = NULL;
1289   TempNewSymbol sig = NULL;
1290   if (name_jh != NULL) {
1291     name = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(name_jh));
1292     if (name == NULL)  return 0; // a match is not possible
1293   }
1294   if (sig_jh != NULL) {
1295     sig = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(sig_jh));
1296     if (sig == NULL)  return 0; // a match is not possible
1297   }
1298 
1299   KlassHandle caller;
1300   if (caller_jh != NULL) {
1301     oop caller_oop = JNIHandles::resolve_non_null(caller_jh);
1302     if (!java_lang_Class::is_instance(caller_oop))  return -1;
1303     caller = KlassHandle(THREAD, java_lang_Class::as_klassOop(caller_oop));
1304   }
1305 
1306   if (name != NULL && sig != NULL && results.not_null()) {
1307     // try a direct resolve
1308     // %%% TO DO
1309   }
1310 
1311   int res = MethodHandles::find_MemberNames(k, name, sig, mflags,
1312                                             caller, skip, results);
1313   // TO DO: expand at least some of the MemberNames, to avoid massive callbacks
1314   return res;
1315 }
1316 JVM_END
1317 
1318 JVM_ENTRY(void, MHN_setCallSiteTargetNormal(JNIEnv* env, jobject igcls, jobject call_site_jh, jobject target_jh)) {
1319   Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
1320   Handle target   (THREAD, JNIHandles::resolve(target_jh));
1321   {
1322     // Walk all nmethods depending on this call site.
1323     MutexLocker mu(Compile_lock, thread);
1324     Universe::flush_dependents_on(call_site, target);
1325     java_lang_invoke_CallSite::set_target(call_site(), target());
1326   }
1327 }
1328 JVM_END
1329 
1330 JVM_ENTRY(void, MHN_setCallSiteTargetVolatile(JNIEnv* env, jobject igcls, jobject call_site_jh, jobject target_jh)) {
1331   Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
1332   Handle target   (THREAD, JNIHandles::resolve(target_jh));
1333   {
1334     // Walk all nmethods depending on this call site.
1335     MutexLocker mu(Compile_lock, thread);
1336     Universe::flush_dependents_on(call_site, target);
1337     java_lang_invoke_CallSite::set_target_volatile(call_site(), target());
1338   }
1339 }
1340 JVM_END
1341 
1342 /**
1343  * Throws a java/lang/UnsupportedOperationException unconditionally.
1344  * This is required by the specification of MethodHandle.invoke if
1345  * invoked directly.
1346  */
1347 JVM_ENTRY(jobject, MH_invoke_UOE(JNIEnv* env, jobject mh, jobjectArray args)) {
1348   THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "MethodHandle.invoke cannot be invoked reflectively");
1349   return NULL;
1350 }
1351 JVM_END
1352 
1353 /**
1354  * Throws a java/lang/UnsupportedOperationException unconditionally.
1355  * This is required by the specification of MethodHandle.invokeExact if
1356  * invoked directly.
1357  */
1358 JVM_ENTRY(jobject, MH_invokeExact_UOE(JNIEnv* env, jobject mh, jobjectArray args)) {
1359   THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "MethodHandle.invokeExact cannot be invoked reflectively");
1360   return NULL;
1361 }
1362 JVM_END
1363 
1364 /// JVM_RegisterMethodHandleMethods
1365 
1366 #undef CS  // Solaris builds complain
1367 
1368 #define LANG "Ljava/lang/"
1369 #define JLINV "Ljava/lang/invoke/"
1370 
1371 #define OBJ   LANG"Object;"
1372 #define CLS   LANG"Class;"
1373 #define STRG  LANG"String;"
1374 #define CS    JLINV"CallSite;"
1375 #define MT    JLINV"MethodType;"
1376 #define MH    JLINV"MethodHandle;"
1377 #define MEM   JLINV"MemberName;"
1378 
1379 #define CC (char*)  /*cast a literal from (const char*)*/
1380 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1381 
1382 // These are the native methods on java.lang.invoke.MethodHandleNatives.
1383 static JNINativeMethod MHN_methods[] = {
1384   {CC"init",                      CC"("MEM""OBJ")V",                     FN_PTR(MHN_init_Mem)},
1385   {CC"expand",                    CC"("MEM")V",                          FN_PTR(MHN_expand_Mem)},
1386   {CC"resolve",                   CC"("MEM""CLS")"MEM,                   FN_PTR(MHN_resolve_Mem)},
1387   {CC"getConstant",               CC"(I)I",                              FN_PTR(MHN_getConstant)},
1388   //  static native int getNamedCon(int which, Object[] name)
1389   {CC"getNamedCon",               CC"(I["OBJ")I",                        FN_PTR(MHN_getNamedCon)},
1390   //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
1391   //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
1392   {CC"getMembers",                CC"("CLS""STRG""STRG"I"CLS"I["MEM")I", FN_PTR(MHN_getMembers)},
1393   {CC"objectFieldOffset",         CC"("MEM")J",                          FN_PTR(MHN_objectFieldOffset)},
1394   {CC"setCallSiteTargetNormal",   CC"("CS""MH")V",                       FN_PTR(MHN_setCallSiteTargetNormal)},
1395   {CC"setCallSiteTargetVolatile", CC"("CS""MH")V",                       FN_PTR(MHN_setCallSiteTargetVolatile)},
1396   {CC"staticFieldOffset",         CC"("MEM")J",                          FN_PTR(MHN_staticFieldOffset)},
1397   {CC"staticFieldBase",           CC"("MEM")"OBJ,                        FN_PTR(MHN_staticFieldBase)},
1398   {CC"getMemberVMInfo",           CC"("MEM")"OBJ,                        FN_PTR(MHN_getMemberVMInfo)}
1399 };
1400 
1401 static JNINativeMethod MH_methods[] = {
1402   // UnsupportedOperationException throwers
1403   {CC"invoke",                    CC"(["OBJ")"OBJ,                       FN_PTR(MH_invoke_UOE)},
1404   {CC"invokeExact",               CC"(["OBJ")"OBJ,                       FN_PTR(MH_invokeExact_UOE)}
1405 };
1406 
1407 /**
1408  * Helper method to register native methods.
1409  */
1410 static bool register_natives(JNIEnv* env, jclass clazz, const JNINativeMethod* methods, jint nMethods) {
1411   int status = env->RegisterNatives(clazz, methods, nMethods);
1412   if (status != JNI_OK || env->ExceptionOccurred()) {
1413     warning("JSR 292 method handle code is mismatched to this JVM.  Disabling support.");
1414     env->ExceptionClear();
1415     return false;
1416   }
1417   return true;
1418 }
1419 
1420 /**
1421  * This one function is exported, used by NativeLookup.
1422  */
1423 JVM_ENTRY(void, JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass MHN_class)) {
1424   if (!EnableInvokeDynamic) {
1425     warning("JSR 292 is disabled in this JVM.  Use -XX:+UnlockDiagnosticVMOptions -XX:+EnableInvokeDynamic to enable.");
1426     return;  // bind nothing
1427   }
1428 
1429   assert(!MethodHandles::enabled(), "must not be enabled");
1430   bool enable_MH = true;
1431 
1432   jclass MH_class = NULL;
1433   if (SystemDictionary::MethodHandle_klass() == NULL) {
1434     enable_MH = false;
1435   } else {
1436     oop mirror = Klass::cast(SystemDictionary::MethodHandle_klass())->java_mirror();
1437     MH_class = (jclass) JNIHandles::make_local(env, mirror);
1438   }
1439 
1440   if (enable_MH) {
1441     ThreadToNativeFromVM ttnfv(thread);
1442 
1443     if (enable_MH) {
1444       enable_MH = register_natives(env, MHN_class, MHN_methods, sizeof(MHN_methods)/sizeof(JNINativeMethod));
1445     }
1446     if (enable_MH) {
1447       enable_MH = register_natives(env, MH_class, MH_methods, sizeof(MH_methods)/sizeof(JNINativeMethod));
1448     }
1449   }
1450 
1451   if (TraceInvokeDynamic) {
1452     tty->print_cr("MethodHandle support loaded (using LambdaForms)");
1453   }
1454 
1455   if (enable_MH) {
1456     MethodHandles::generate_adapters();
1457     MethodHandles::set_enabled(true);
1458   }
1459 }
1460 JVM_END