1 /*
   2  * Copyright (c) 2008, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   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/javaClasses.inline.hpp"
  27 #include "classfile/stringTable.hpp"
  28 #include "code/codeCache.hpp"
  29 #include "code/dependencyContext.hpp"
  30 #include "compiler/compileBroker.hpp"
  31 #include "interpreter/interpreter.hpp"
  32 #include "interpreter/oopMapCache.hpp"
  33 #include "interpreter/linkResolver.hpp"
  34 #include "memory/allocation.inline.hpp"
  35 #include "memory/oopFactory.hpp"
  36 #include "memory/resourceArea.hpp"
  37 #include "oops/objArrayOop.inline.hpp"
  38 #include "oops/oop.inline.hpp"
  39 #include "prims/methodHandles.hpp"
  40 #include "runtime/compilationPolicy.hpp"
  41 #include "runtime/javaCalls.hpp"
  42 #include "runtime/timerTrace.hpp"
  43 #include "runtime/reflection.hpp"
  44 #include "runtime/signature.hpp"
  45 #include "runtime/stubRoutines.hpp"
  46 #include "utilities/exceptions.hpp"
  47 
  48 
  49 /*
  50  * JSR 292 reference implementation: method handles
  51  * The JDK 7 reference implementation represented method handle
  52  * combinations as chains.  Each link in the chain had a "vmentry"
  53  * field which pointed at a bit of assembly code which performed
  54  * one transformation before dispatching to the next link in the chain.
  55  *
  56  * The current reference implementation pushes almost all code generation
  57  * responsibility to (trusted) Java code.  A method handle contains a
  58  * pointer to its "LambdaForm", which embodies all details of the method
  59  * handle's behavior.  The LambdaForm is a normal Java object, managed
  60  * by a runtime coded in Java.
  61  */
  62 
  63 bool MethodHandles::_enabled = false; // set true after successful native linkage
  64 MethodHandlesAdapterBlob* MethodHandles::_adapter_code = NULL;
  65 
  66 /**
  67  * Generates method handle adapters. Returns 'false' if memory allocation
  68  * failed and true otherwise.
  69  */
  70 void MethodHandles::generate_adapters() {
  71   assert(SystemDictionary::MethodHandle_klass() != NULL, "should be present");
  72   assert(_adapter_code == NULL, "generate only once");
  73 
  74   ResourceMark rm;
  75   TraceTime timer("MethodHandles adapters generation", TRACETIME_LOG(Info, startuptime));
  76   _adapter_code = MethodHandlesAdapterBlob::create(adapter_code_size);
  77   CodeBuffer code(_adapter_code);
  78   MethodHandlesAdapterGenerator g(&code);
  79   g.generate();
  80   code.log_section_sizes("MethodHandlesAdapterBlob");
  81 }
  82 
  83 //------------------------------------------------------------------------------
  84 // MethodHandlesAdapterGenerator::generate
  85 //
  86 void MethodHandlesAdapterGenerator::generate() {
  87   // Generate generic method handle adapters.
  88   // Generate interpreter entries
  89   for (Interpreter::MethodKind mk = Interpreter::method_handle_invoke_FIRST;
  90        mk <= Interpreter::method_handle_invoke_LAST;
  91        mk = Interpreter::MethodKind(1 + (int)mk)) {
  92     vmIntrinsics::ID iid = Interpreter::method_handle_intrinsic(mk);
  93     StubCodeMark mark(this, "MethodHandle::interpreter_entry", vmIntrinsics::name_at(iid));
  94     address entry = MethodHandles::generate_method_handle_interpreter_entry(_masm, iid);
  95     if (entry != NULL) {
  96       Interpreter::set_entry_for_kind(mk, entry);
  97     }
  98     // If the entry is not set, it will throw AbstractMethodError.
  99   }
 100 }
 101 
 102 void MethodHandles::set_enabled(bool z) {
 103   if (_enabled != z) {
 104     guarantee(z, "can only enable once");
 105     _enabled = z;
 106   }
 107 }
 108 
 109 // MemberName support
 110 
 111 // import java_lang_invoke_MemberName.*
 112 enum {
 113   IS_METHOD            = java_lang_invoke_MemberName::MN_IS_METHOD,
 114   IS_CONSTRUCTOR       = java_lang_invoke_MemberName::MN_IS_CONSTRUCTOR,
 115   IS_FIELD             = java_lang_invoke_MemberName::MN_IS_FIELD,
 116   IS_TYPE              = java_lang_invoke_MemberName::MN_IS_TYPE,
 117   CALLER_SENSITIVE     = java_lang_invoke_MemberName::MN_CALLER_SENSITIVE,
 118   REFERENCE_KIND_SHIFT = java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT,
 119   REFERENCE_KIND_MASK  = java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK,
 120   SEARCH_SUPERCLASSES  = java_lang_invoke_MemberName::MN_SEARCH_SUPERCLASSES,
 121   SEARCH_INTERFACES    = java_lang_invoke_MemberName::MN_SEARCH_INTERFACES,
 122   ALL_KINDS      = IS_METHOD | IS_CONSTRUCTOR | IS_FIELD | IS_TYPE
 123 };
 124 
 125 oop MethodHandles::init_MemberName(Handle mname, Handle target, TRAPS) {
 126   // This method is used from java.lang.invoke.MemberName constructors.
 127   // It fills in the new MemberName from a java.lang.reflect.Member.
 128   Thread* thread = Thread::current();
 129   oop target_oop = target();
 130   Klass* 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     Klass* k = java_lang_Class::as_Klass(clazz);
 135     if (k != NULL && k->is_instance_klass()) {
 136       fieldDescriptor fd(InstanceKlass::cast(k), slot);
 137       oop mname2 = init_field_MemberName(mname, fd);
 138       if (mname2 != NULL) {
 139         // Since we have the reified name and type handy, add them to the result.
 140         if (java_lang_invoke_MemberName::name(mname2) == NULL)
 141           java_lang_invoke_MemberName::set_name(mname2, java_lang_reflect_Field::name(target_oop));
 142         if (java_lang_invoke_MemberName::type(mname2) == NULL)
 143           java_lang_invoke_MemberName::set_type(mname2, java_lang_reflect_Field::type(target_oop));
 144       }
 145       return mname2;
 146     }
 147   } else if (target_klass == SystemDictionary::reflect_Method_klass()) {
 148     oop clazz  = java_lang_reflect_Method::clazz(target_oop);
 149     int slot   = java_lang_reflect_Method::slot(target_oop);
 150     Klass* k = java_lang_Class::as_Klass(clazz);
 151     if (k != NULL && k->is_instance_klass()) {
 152       Method* m = InstanceKlass::cast(k)->method_with_idnum(slot);
 153       if (m == NULL || is_signature_polymorphic(m->intrinsic_id()))
 154         return NULL;            // do not resolve unless there is a concrete signature
 155       CallInfo info(m, k, CHECK_NULL);
 156       return init_method_MemberName(mname, info);
 157     }
 158   } else if (target_klass == SystemDictionary::reflect_Constructor_klass()) {
 159     oop clazz  = java_lang_reflect_Constructor::clazz(target_oop);
 160     int slot   = java_lang_reflect_Constructor::slot(target_oop);
 161     Klass* k = java_lang_Class::as_Klass(clazz);
 162     if (k != NULL && k->is_instance_klass()) {
 163       Method* m = InstanceKlass::cast(k)->method_with_idnum(slot);
 164       if (m == NULL)  return NULL;
 165       CallInfo info(m, k, CHECK_NULL);
 166       return init_method_MemberName(mname, info);
 167     }
 168   }
 169   return NULL;
 170 }
 171 
 172 oop MethodHandles::init_method_MemberName(Handle mname, CallInfo& info) {
 173   assert(info.resolved_appendix().is_null(), "only normal methods here");
 174   methodHandle m = info.resolved_method();
 175   assert(m.not_null(), "null method handle");
 176   Klass* m_klass = m->method_holder();
 177   assert(m_klass != NULL, "null holder for method handle");
 178   int flags = (jushort)( m->access_flags().as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS );
 179   int vmindex = Method::invalid_vtable_index;
 180 
 181   switch (info.call_kind()) {
 182   case CallInfo::itable_call:
 183     vmindex = info.itable_index();
 184     // More importantly, the itable index only works with the method holder.
 185     assert(m_klass->verify_itable_index(vmindex), "");
 186     flags |= IS_METHOD | (JVM_REF_invokeInterface << REFERENCE_KIND_SHIFT);
 187     if (TraceInvokeDynamic) {
 188       ttyLocker ttyl;
 189       ResourceMark rm;
 190       tty->print_cr("memberName: invokeinterface method_holder::method: %s, itableindex: %d, access_flags:",
 191             Method::name_and_sig_as_C_string(m->method_holder(), m->name(), m->signature()),
 192             vmindex);
 193        m->access_flags().print_on(tty);
 194        if (!m->is_abstract()) {
 195          tty->print("default");
 196        }
 197        tty->cr();
 198     }
 199     break;
 200 
 201   case CallInfo::vtable_call:
 202     vmindex = info.vtable_index();
 203     flags |= IS_METHOD | (JVM_REF_invokeVirtual << REFERENCE_KIND_SHIFT);
 204     assert(info.resolved_klass()->is_subtype_of(m_klass), "virtual call must be type-safe");
 205     if (m_klass->is_interface()) {
 206       // This is a vtable call to an interface method (abstract "miranda method" or default method).
 207       // The vtable index is meaningless without a class (not interface) receiver type, so get one.
 208       // (LinkResolver should help us figure this out.)
 209       Klass* m_klass_non_interface = info.resolved_klass();
 210       if (m_klass_non_interface->is_interface()) {
 211         m_klass_non_interface = SystemDictionary::Object_klass();
 212 #ifdef ASSERT
 213         { ResourceMark rm;
 214           Method* m2 = m_klass_non_interface->vtable().method_at(vmindex);
 215           assert(m->name() == m2->name() && m->signature() == m2->signature(),
 216                  "at %d, %s != %s", vmindex,
 217                  m->name_and_sig_as_C_string(), m2->name_and_sig_as_C_string());
 218         }
 219 #endif //ASSERT
 220       }
 221       if (!m->is_public()) {
 222         assert(m->is_public(), "virtual call must be to public interface method");
 223         return NULL;  // elicit an error later in product build
 224       }
 225       assert(info.resolved_klass()->is_subtype_of(m_klass_non_interface), "virtual call must be type-safe");
 226       m_klass = m_klass_non_interface;
 227     }
 228     if (TraceInvokeDynamic) {
 229       ttyLocker ttyl;
 230       ResourceMark rm;
 231       tty->print_cr("memberName: invokevirtual method_holder::method: %s, receiver: %s, vtableindex: %d, access_flags:",
 232             Method::name_and_sig_as_C_string(m->method_holder(), m->name(), m->signature()),
 233             m_klass->internal_name(), vmindex);
 234        m->access_flags().print_on(tty);
 235        if (m->is_default_method()) {
 236          tty->print("default");
 237        }
 238        tty->cr();
 239     }
 240     break;
 241 
 242   case CallInfo::direct_call:
 243     vmindex = Method::nonvirtual_vtable_index;
 244     if (m->is_static()) {
 245       flags |= IS_METHOD      | (JVM_REF_invokeStatic  << REFERENCE_KIND_SHIFT);
 246     } else if (m->is_initializer()) {
 247       flags |= IS_CONSTRUCTOR | (JVM_REF_invokeSpecial << REFERENCE_KIND_SHIFT);
 248     } else {
 249       flags |= IS_METHOD      | (JVM_REF_invokeSpecial << REFERENCE_KIND_SHIFT);
 250     }
 251     break;
 252 
 253   default:  assert(false, "bad CallInfo");  return NULL;
 254   }
 255 
 256   // @CallerSensitive annotation detected
 257   if (m->caller_sensitive()) {
 258     flags |= CALLER_SENSITIVE;
 259   }
 260 
 261   Handle resolved_method = info.resolved_method_name();
 262   assert(java_lang_invoke_ResolvedMethodName::vmtarget(resolved_method()) == m(),
 263          "Should not change after link resolultion");
 264 
 265   oop mname_oop = mname();
 266   java_lang_invoke_MemberName::set_flags  (mname_oop, flags);
 267   java_lang_invoke_MemberName::set_method (mname_oop, resolved_method());
 268   java_lang_invoke_MemberName::set_vmindex(mname_oop, vmindex);   // vtable/itable index
 269   java_lang_invoke_MemberName::set_clazz  (mname_oop, m_klass->java_mirror());
 270   // Note:  name and type can be lazily computed by resolve_MemberName,
 271   // if Java code needs them as resolved String and MethodType objects.
 272   // If relevant, the vtable or itable value is stored as vmindex.
 273   // This is done eagerly, since it is readily available without
 274   // constructing any new objects.
 275   return mname();
 276 }
 277 
 278 oop MethodHandles::init_field_MemberName(Handle mname, fieldDescriptor& fd, bool is_setter) {
 279   int flags = (jushort)( fd.access_flags().as_short() & JVM_RECOGNIZED_FIELD_MODIFIERS );
 280   flags |= IS_FIELD | ((fd.is_static() ? JVM_REF_getStatic : JVM_REF_getField) << REFERENCE_KIND_SHIFT);
 281   if (is_setter)  flags += ((JVM_REF_putField - JVM_REF_getField) << REFERENCE_KIND_SHIFT);
 282   int vmindex        = fd.offset();  // determines the field uniquely when combined with static bit
 283 
 284   oop mname_oop = mname();
 285   java_lang_invoke_MemberName::set_flags  (mname_oop, flags);
 286   java_lang_invoke_MemberName::set_method (mname_oop, NULL);
 287   java_lang_invoke_MemberName::set_vmindex(mname_oop, vmindex);
 288   java_lang_invoke_MemberName::set_clazz  (mname_oop, fd.field_holder()->java_mirror());
 289 
 290   oop type = field_signature_type_or_null(fd.signature());
 291   oop name = field_name_or_null(fd.name());
 292   if (name != NULL)
 293     java_lang_invoke_MemberName::set_name(mname_oop,   name);
 294   if (type != NULL)
 295     java_lang_invoke_MemberName::set_type(mname_oop,   type);
 296   // Note:  name and type can be lazily computed by resolve_MemberName,
 297   // if Java code needs them as resolved String and Class objects.
 298   // Note that the incoming type oop might be pre-resolved (non-null).
 299   // The base clazz and field offset (vmindex) must be eagerly stored,
 300   // because they unambiguously identify the field.
 301   // Although the fieldDescriptor::_index would also identify the field,
 302   // we do not use it, because it is harder to decode.
 303   // TO DO: maybe intern mname_oop
 304   return mname();
 305 }
 306 
 307 // JVM 2.9 Special Methods:
 308 // A method is signature polymorphic if and only if all of the following conditions hold :
 309 // * It is declared in the java.lang.invoke.MethodHandle/VarHandle classes.
 310 // * It has a single formal parameter of type Object[].
 311 // * It has a return type of Object for a polymorphic return type, otherwise a fixed return type.
 312 // * It has the ACC_VARARGS and ACC_NATIVE flags set.
 313 bool MethodHandles::is_method_handle_invoke_name(Klass* klass, Symbol* name) {
 314   if (klass == NULL)
 315     return false;
 316   // The following test will fail spuriously during bootstrap of MethodHandle itself:
 317   //    if (klass != SystemDictionary::MethodHandle_klass())
 318   // Test the name instead:
 319   if (klass->name() != vmSymbols::java_lang_invoke_MethodHandle() &&
 320       klass->name() != vmSymbols::java_lang_invoke_VarHandle()) {
 321     return false;
 322   }
 323 
 324   // Look up signature polymorphic method with polymorphic return type
 325   Symbol* poly_sig = vmSymbols::object_array_object_signature();
 326   InstanceKlass* iklass = InstanceKlass::cast(klass);
 327   Method* m = iklass->find_method(name, poly_sig);
 328   if (m != NULL) {
 329     int required = JVM_ACC_NATIVE | JVM_ACC_VARARGS;
 330     int flags = m->access_flags().as_int();
 331     if ((flags & required) == required) {
 332       return true;
 333     }
 334   }
 335 
 336   // Look up signature polymorphic method with non-polymorphic (non Object) return type
 337   int me;
 338   int ms = iklass->find_method_by_name(name, &me);
 339   if (ms == -1) return false;
 340   for (; ms < me; ms++) {
 341     Method* m = iklass->methods()->at(ms);
 342     int required = JVM_ACC_NATIVE | JVM_ACC_VARARGS;
 343     int flags = m->access_flags().as_int();
 344     if ((flags & required) == required && ArgumentCount(m->signature()).size() == 1) {
 345       return true;
 346     }
 347   }
 348   return false;
 349 }
 350 
 351 
 352 Symbol* MethodHandles::signature_polymorphic_intrinsic_name(vmIntrinsics::ID iid) {
 353   assert(is_signature_polymorphic_intrinsic(iid), "%d %s", iid, vmIntrinsics::name_at(iid));
 354   switch (iid) {
 355   case vmIntrinsics::_invokeBasic:      return vmSymbols::invokeBasic_name();
 356   case vmIntrinsics::_linkToVirtual:    return vmSymbols::linkToVirtual_name();
 357   case vmIntrinsics::_linkToStatic:     return vmSymbols::linkToStatic_name();
 358   case vmIntrinsics::_linkToSpecial:    return vmSymbols::linkToSpecial_name();
 359   case vmIntrinsics::_linkToInterface:  return vmSymbols::linkToInterface_name();
 360   default:
 361     fatal("unexpected intrinsic id: %d %s", iid, vmIntrinsics::name_at(iid));
 362     return 0;
 363   }
 364 }
 365 
 366 Bytecodes::Code MethodHandles::signature_polymorphic_intrinsic_bytecode(vmIntrinsics::ID id) {
 367   switch(id) {
 368     case vmIntrinsics::_linkToVirtual:   return Bytecodes::_invokevirtual;
 369     case vmIntrinsics::_linkToInterface: return Bytecodes::_invokeinterface;
 370     case vmIntrinsics::_linkToStatic:    return Bytecodes::_invokestatic;
 371     case vmIntrinsics::_linkToSpecial:   return Bytecodes::_invokespecial;
 372     case vmIntrinsics::_invokeBasic:     return Bytecodes::_invokehandle;
 373     default:
 374       fatal("unexpected id: (%d) %s", (uint)id, vmIntrinsics::name_at(id));
 375       return Bytecodes::_illegal;
 376   }
 377 }
 378 
 379 int MethodHandles::signature_polymorphic_intrinsic_ref_kind(vmIntrinsics::ID iid) {
 380   switch (iid) {
 381   case vmIntrinsics::_invokeBasic:      return 0;
 382   case vmIntrinsics::_linkToVirtual:    return JVM_REF_invokeVirtual;
 383   case vmIntrinsics::_linkToStatic:     return JVM_REF_invokeStatic;
 384   case vmIntrinsics::_linkToSpecial:    return JVM_REF_invokeSpecial;
 385   case vmIntrinsics::_linkToInterface:  return JVM_REF_invokeInterface;
 386   default:
 387     fatal("unexpected intrinsic id: %d %s", iid, vmIntrinsics::name_at(iid));
 388     return 0;
 389   }
 390 }
 391 
 392 vmIntrinsics::ID MethodHandles::signature_polymorphic_name_id(Symbol* name) {
 393   vmSymbols::SID name_id = vmSymbols::find_sid(name);
 394   switch (name_id) {
 395   // The ID _invokeGeneric stands for all non-static signature-polymorphic methods, except built-ins.
 396   case vmSymbols::VM_SYMBOL_ENUM_NAME(invoke_name):           return vmIntrinsics::_invokeGeneric;
 397   // The only built-in non-static signature-polymorphic method is MethodHandle.invokeBasic:
 398   case vmSymbols::VM_SYMBOL_ENUM_NAME(invokeBasic_name):      return vmIntrinsics::_invokeBasic;
 399 
 400   // There is one static signature-polymorphic method for each JVM invocation mode.
 401   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToVirtual_name):    return vmIntrinsics::_linkToVirtual;
 402   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToStatic_name):     return vmIntrinsics::_linkToStatic;
 403   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToSpecial_name):    return vmIntrinsics::_linkToSpecial;
 404   case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToInterface_name):  return vmIntrinsics::_linkToInterface;
 405   default:                                                    break;
 406   }
 407 
 408   // Cover the case of invokeExact and any future variants of invokeFoo.
 409   Klass* mh_klass = SystemDictionary::well_known_klass(
 410                               SystemDictionary::WK_KLASS_ENUM_NAME(MethodHandle_klass) );
 411   if (mh_klass != NULL && is_method_handle_invoke_name(mh_klass, name)) {
 412     return vmIntrinsics::_invokeGeneric;
 413   }
 414 
 415   // Cover the case of methods on VarHandle.
 416   Klass* vh_klass = SystemDictionary::well_known_klass(
 417                               SystemDictionary::WK_KLASS_ENUM_NAME(VarHandle_klass) );
 418   if (vh_klass != NULL && is_method_handle_invoke_name(vh_klass, name)) {
 419     return vmIntrinsics::_invokeGeneric;
 420   }
 421 
 422   // Note: The pseudo-intrinsic _compiledLambdaForm is never linked against.
 423   // Instead it is used to mark lambda forms bound to invokehandle or invokedynamic.
 424   return vmIntrinsics::_none;
 425 }
 426 
 427 vmIntrinsics::ID MethodHandles::signature_polymorphic_name_id(Klass* klass, Symbol* name) {
 428   if (klass != NULL &&
 429       (klass->name() == vmSymbols::java_lang_invoke_MethodHandle() ||
 430        klass->name() == vmSymbols::java_lang_invoke_VarHandle())) {
 431     vmIntrinsics::ID iid = signature_polymorphic_name_id(name);
 432     if (iid != vmIntrinsics::_none)
 433       return iid;
 434     if (is_method_handle_invoke_name(klass, name))
 435       return vmIntrinsics::_invokeGeneric;
 436   }
 437   return vmIntrinsics::_none;
 438 }
 439 
 440 
 441 // convert the external string or reflective type to an internal signature
 442 Symbol* MethodHandles::lookup_signature(oop type_str, bool intern_if_not_found, TRAPS) {
 443   if (java_lang_invoke_MethodType::is_instance(type_str)) {
 444     return java_lang_invoke_MethodType::as_signature(type_str, intern_if_not_found, THREAD);
 445   } else if (java_lang_Class::is_instance(type_str)) {
 446     return java_lang_Class::as_signature(type_str, false, THREAD);
 447   } else if (java_lang_String::is_instance_inlined(type_str)) {
 448     if (intern_if_not_found) {
 449       return java_lang_String::as_symbol(type_str, THREAD);
 450     } else {
 451       return java_lang_String::as_symbol_or_null(type_str);
 452     }
 453   } else {
 454     THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized type", NULL);
 455   }
 456 }
 457 
 458 static const char OBJ_SIG[] = "Ljava/lang/Object;";
 459 enum { OBJ_SIG_LEN = 18 };
 460 
 461 bool MethodHandles::is_basic_type_signature(Symbol* sig) {
 462   assert(vmSymbols::object_signature()->utf8_length() == (int)OBJ_SIG_LEN, "");
 463   assert(vmSymbols::object_signature()->equals(OBJ_SIG), "");
 464   const int len = sig->utf8_length();
 465   for (int i = 0; i < len; i++) {
 466     switch (sig->byte_at(i)) {
 467     case 'L':
 468       // only java/lang/Object is valid here
 469       if (sig->index_of_at(i, OBJ_SIG, OBJ_SIG_LEN) != i)
 470         return false;
 471       i += OBJ_SIG_LEN-1;  //-1 because of i++ in loop
 472       continue;
 473     case '(': case ')': case 'V':
 474     case 'I': case 'J': case 'F': case 'D':
 475       continue;
 476     //case '[':
 477     //case 'Z': case 'B': case 'C': case 'S':
 478     default:
 479       return false;
 480     }
 481   }
 482   return true;
 483 }
 484 
 485 Symbol* MethodHandles::lookup_basic_type_signature(Symbol* sig, bool keep_last_arg, TRAPS) {
 486   Symbol* bsig = NULL;
 487   if (sig == NULL) {
 488     return sig;
 489   } else if (is_basic_type_signature(sig)) {
 490     sig->increment_refcount();
 491     return sig;  // that was easy
 492   } else if (sig->byte_at(0) != '(') {
 493     BasicType bt = char2type(sig->byte_at(0));
 494     if (is_subword_type(bt)) {
 495       bsig = vmSymbols::int_signature();
 496     } else {
 497       assert(bt == T_OBJECT || bt == T_ARRAY, "is_basic_type_signature was false");
 498       bsig = vmSymbols::object_signature();
 499     }
 500   } else {
 501     ResourceMark rm;
 502     stringStream buffer(128);
 503     buffer.put('(');
 504     int arg_pos = 0, keep_arg_pos = -1;
 505     if (keep_last_arg)
 506       keep_arg_pos = ArgumentCount(sig).size() - 1;
 507     for (SignatureStream ss(sig); !ss.is_done(); ss.next()) {
 508       BasicType bt = ss.type();
 509       size_t this_arg_pos = buffer.size();
 510       if (ss.at_return_type()) {
 511         buffer.put(')');
 512       }
 513       if (arg_pos == keep_arg_pos) {
 514         buffer.write((char*) ss.raw_bytes(),
 515                      (int)   ss.raw_length());
 516       } else if (bt == T_OBJECT || bt == T_ARRAY) {
 517         buffer.write(OBJ_SIG, OBJ_SIG_LEN);
 518       } else {
 519         if (is_subword_type(bt))
 520           bt = T_INT;
 521         buffer.put(type2char(bt));
 522       }
 523       arg_pos++;
 524     }
 525     const char* sigstr =       buffer.base();
 526     int         siglen = (int) buffer.size();
 527     bsig = SymbolTable::new_symbol(sigstr, siglen, THREAD);
 528   }
 529   assert(is_basic_type_signature(bsig) ||
 530          // detune assert in case the injected argument is not a basic type:
 531          keep_last_arg, "");
 532   return bsig;
 533 }
 534 
 535 void MethodHandles::print_as_basic_type_signature_on(outputStream* st,
 536                                                      Symbol* sig,
 537                                                      bool keep_arrays,
 538                                                      bool keep_basic_names) {
 539   st = st ? st : tty;
 540   int len  = sig->utf8_length();
 541   int array = 0;
 542   bool prev_type = false;
 543   for (int i = 0; i < len; i++) {
 544     char ch = sig->byte_at(i);
 545     switch (ch) {
 546     case '(': case ')':
 547       prev_type = false;
 548       st->put(ch);
 549       continue;
 550     case '[':
 551       if (!keep_basic_names && keep_arrays)
 552         st->put(ch);
 553       array++;
 554       continue;
 555     case 'L':
 556       {
 557         if (prev_type)  st->put(',');
 558         int start = i+1, slash = start;
 559         while (++i < len && (ch = sig->byte_at(i)) != ';') {
 560           if (ch == '/' || ch == '.' || ch == '$')  slash = i+1;
 561         }
 562         if (slash < i)  start = slash;
 563         if (!keep_basic_names) {
 564           st->put('L');
 565         } else {
 566           for (int j = start; j < i; j++)
 567             st->put(sig->byte_at(j));
 568           prev_type = true;
 569         }
 570         break;
 571       }
 572     default:
 573       {
 574         if (array && char2type(ch) != T_ILLEGAL && !keep_arrays) {
 575           ch = '[';
 576           array = 0;
 577         }
 578         if (prev_type)  st->put(',');
 579         const char* n = NULL;
 580         if (keep_basic_names)
 581           n = type2name(char2type(ch));
 582         if (n == NULL) {
 583           // unknown letter, or we don't want to know its name
 584           st->put(ch);
 585         } else {
 586           st->print("%s", n);
 587           prev_type = true;
 588         }
 589         break;
 590       }
 591     }
 592     // Switch break goes here to take care of array suffix:
 593     if (prev_type) {
 594       while (array > 0) {
 595         st->print("[]");
 596         --array;
 597       }
 598     }
 599     array = 0;
 600   }
 601 }
 602 
 603 
 604 
 605 static oop object_java_mirror() {
 606   return SystemDictionary::Object_klass()->java_mirror();
 607 }
 608 
 609 oop MethodHandles::field_name_or_null(Symbol* s) {
 610   if (s == NULL)  return NULL;
 611   return StringTable::lookup(s);
 612 }
 613 
 614 oop MethodHandles::field_signature_type_or_null(Symbol* s) {
 615   if (s == NULL)  return NULL;
 616   BasicType bt = FieldType::basic_type(s);
 617   if (is_java_primitive(bt)) {
 618     assert(s->utf8_length() == 1, "");
 619     return java_lang_Class::primitive_mirror(bt);
 620   }
 621   // Here are some more short cuts for common types.
 622   // They are optional, since reference types can be resolved lazily.
 623   if (bt == T_OBJECT) {
 624     if (s == vmSymbols::object_signature()) {
 625       return object_java_mirror();
 626     } else if (s == vmSymbols::class_signature()) {
 627       return SystemDictionary::Class_klass()->java_mirror();
 628     } else if (s == vmSymbols::string_signature()) {
 629       return SystemDictionary::String_klass()->java_mirror();
 630     }
 631   }
 632   return NULL;
 633 }
 634 
 635 
 636 // An unresolved member name is a mere symbolic reference.
 637 // Resolving it plants a vmtarget/vmindex in it,
 638 // which refers directly to JVM internals.
 639 Handle MethodHandles::resolve_MemberName(Handle mname, Klass* caller, TRAPS) {
 640   Handle empty;
 641   assert(java_lang_invoke_MemberName::is_instance(mname()), "");
 642 
 643   if (java_lang_invoke_MemberName::vmtarget(mname()) != NULL) {
 644     // Already resolved.
 645     DEBUG_ONLY(int vmindex = java_lang_invoke_MemberName::vmindex(mname()));
 646     assert(vmindex >= Method::nonvirtual_vtable_index, "");
 647     return mname;
 648   }
 649 
 650   Handle defc_oop(THREAD, java_lang_invoke_MemberName::clazz(mname()));
 651   Handle name_str(THREAD, java_lang_invoke_MemberName::name( mname()));
 652   Handle type_str(THREAD, java_lang_invoke_MemberName::type( mname()));
 653   int    flags    =       java_lang_invoke_MemberName::flags(mname());
 654   int    ref_kind =       (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
 655   if (!ref_kind_is_valid(ref_kind)) {
 656     THROW_MSG_(vmSymbols::java_lang_InternalError(), "obsolete MemberName format", empty);
 657   }
 658 
 659   DEBUG_ONLY(int old_vmindex);
 660   assert((old_vmindex = java_lang_invoke_MemberName::vmindex(mname())) == 0, "clean input");
 661 
 662   if (defc_oop.is_null() || name_str.is_null() || type_str.is_null()) {
 663     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(), "nothing to resolve", empty);
 664   }
 665 
 666   InstanceKlass* defc = NULL;
 667   {
 668     Klass* defc_klass = java_lang_Class::as_Klass(defc_oop());
 669     if (defc_klass == NULL)  return empty;  // a primitive; no resolution possible
 670     if (!defc_klass->is_instance_klass()) {
 671       if (!defc_klass->is_array_klass())  return empty;
 672       defc_klass = SystemDictionary::Object_klass();
 673     }
 674     defc = InstanceKlass::cast(defc_klass);
 675   }
 676   if (defc == NULL) {
 677     THROW_MSG_(vmSymbols::java_lang_InternalError(), "primitive class", empty);
 678   }
 679   defc->link_class(CHECK_(empty));  // possible safepoint
 680 
 681   // convert the external string name to an internal symbol
 682   TempNewSymbol name = java_lang_String::as_symbol_or_null(name_str());
 683   if (name == NULL)  return empty;  // no such name
 684   if (name == vmSymbols::class_initializer_name())
 685     return empty; // illegal name
 686 
 687   vmIntrinsics::ID mh_invoke_id = vmIntrinsics::_none;
 688   if ((flags & ALL_KINDS) == IS_METHOD &&
 689       (defc == SystemDictionary::MethodHandle_klass()) &&
 690       (ref_kind == JVM_REF_invokeVirtual ||
 691        ref_kind == JVM_REF_invokeSpecial ||
 692        // static invocation mode is required for _linkToVirtual, etc.:
 693        ref_kind == JVM_REF_invokeStatic)) {
 694     vmIntrinsics::ID iid = signature_polymorphic_name_id(name);
 695     if (iid != vmIntrinsics::_none &&
 696         ((ref_kind == JVM_REF_invokeStatic) == is_signature_polymorphic_static(iid))) {
 697       // Virtual methods invoke and invokeExact, plus internal invokers like _invokeBasic.
 698       // For a static reference it could an internal linkage routine like _linkToVirtual, etc.
 699       mh_invoke_id = iid;
 700     }
 701   }
 702 
 703   // convert the external string or reflective type to an internal signature
 704   TempNewSymbol type = lookup_signature(type_str(), (mh_invoke_id != vmIntrinsics::_none), CHECK_(empty));
 705   if (type == NULL)  return empty;  // no such signature exists in the VM
 706 
 707   LinkInfo::AccessCheck access_check = caller != NULL ?
 708                                               LinkInfo::needs_access_check :
 709                                               LinkInfo::skip_access_check;
 710 
 711   // Time to do the lookup.
 712   switch (flags & ALL_KINDS) {
 713   case IS_METHOD:
 714     {
 715       CallInfo result;
 716       LinkInfo link_info(defc, name, type, caller, access_check);
 717       {
 718         assert(!HAS_PENDING_EXCEPTION, "");
 719         if (ref_kind == JVM_REF_invokeStatic) {
 720           LinkResolver::resolve_static_call(result,
 721                         link_info, false, THREAD);
 722         } else if (ref_kind == JVM_REF_invokeInterface) {
 723           LinkResolver::resolve_interface_call(result, Handle(), defc,
 724                         link_info, false, THREAD);
 725         } else if (mh_invoke_id != vmIntrinsics::_none) {
 726           assert(!is_signature_polymorphic_static(mh_invoke_id), "");
 727           LinkResolver::resolve_handle_call(result, link_info, THREAD);
 728         } else if (ref_kind == JVM_REF_invokeSpecial) {
 729           LinkResolver::resolve_special_call(result, Handle(),
 730                         link_info, THREAD);
 731         } else if (ref_kind == JVM_REF_invokeVirtual) {
 732           LinkResolver::resolve_virtual_call(result, Handle(), defc,
 733                         link_info, false, THREAD);
 734         } else {
 735           assert(false, "ref_kind=%d", ref_kind);
 736         }
 737         if (HAS_PENDING_EXCEPTION) {
 738           return empty;
 739         }
 740       }
 741       if (result.resolved_appendix().not_null()) {
 742         // The resolved MemberName must not be accompanied by an appendix argument,
 743         // since there is no way to bind this value into the MemberName.
 744         // Caller is responsible to prevent this from happening.
 745         THROW_MSG_(vmSymbols::java_lang_InternalError(), "appendix", empty);
 746       }
 747       result.set_resolved_method_name(CHECK_(empty));
 748       oop mname2 = init_method_MemberName(mname, result);
 749       return Handle(THREAD, mname2);
 750     }
 751   case IS_CONSTRUCTOR:
 752     {
 753       CallInfo result;
 754       LinkInfo link_info(defc, name, type, caller, access_check);
 755       {
 756         assert(!HAS_PENDING_EXCEPTION, "");
 757         if (name == vmSymbols::object_initializer_name()) {
 758           LinkResolver::resolve_special_call(result, Handle(), link_info, THREAD);
 759         } else {
 760           break;                // will throw after end of switch
 761         }
 762         if (HAS_PENDING_EXCEPTION) {
 763           return empty;
 764         }
 765       }
 766       assert(result.is_statically_bound(), "");
 767       result.set_resolved_method_name(CHECK_(empty));
 768       oop mname2 = init_method_MemberName(mname, result);
 769       return Handle(THREAD, mname2);
 770     }
 771   case IS_FIELD:
 772     {
 773       fieldDescriptor result; // find_field initializes fd if found
 774       {
 775         assert(!HAS_PENDING_EXCEPTION, "");
 776         LinkInfo link_info(defc, name, type, caller, LinkInfo::skip_access_check);
 777         LinkResolver::resolve_field(result, link_info, Bytecodes::_nop, false, THREAD);
 778         if (HAS_PENDING_EXCEPTION) {
 779           return empty;
 780         }
 781       }
 782       oop mname2 = init_field_MemberName(mname, result, ref_kind_is_setter(ref_kind));
 783       return Handle(THREAD, mname2);
 784     }
 785   default:
 786     THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format", empty);
 787   }
 788 
 789   return empty;
 790 }
 791 
 792 // Conversely, a member name which is only initialized from JVM internals
 793 // may have null defc, name, and type fields.
 794 // Resolving it plants a vmtarget/vmindex in it,
 795 // which refers directly to JVM internals.
 796 void MethodHandles::expand_MemberName(Handle mname, int suppress, TRAPS) {
 797   assert(java_lang_invoke_MemberName::is_instance(mname()), "");
 798 
 799   bool have_defc = (java_lang_invoke_MemberName::clazz(mname()) != NULL);
 800   bool have_name = (java_lang_invoke_MemberName::name(mname()) != NULL);
 801   bool have_type = (java_lang_invoke_MemberName::type(mname()) != NULL);
 802   int flags      = java_lang_invoke_MemberName::flags(mname());
 803 
 804   if (suppress != 0) {
 805     if (suppress & _suppress_defc)  have_defc = true;
 806     if (suppress & _suppress_name)  have_name = true;
 807     if (suppress & _suppress_type)  have_type = true;
 808   }
 809 
 810   if (have_defc && have_name && have_type)  return;  // nothing needed
 811 
 812   switch (flags & ALL_KINDS) {
 813   case IS_METHOD:
 814   case IS_CONSTRUCTOR:
 815     {
 816       Method* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
 817       if (vmtarget == NULL) {
 818         THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "nothing to expand");
 819       }
 820       methodHandle m(THREAD, vmtarget);
 821       DEBUG_ONLY(vmtarget = NULL);  // safety
 822       if (!have_defc) {
 823         InstanceKlass* defc = m->method_holder();
 824         java_lang_invoke_MemberName::set_clazz(mname(), defc->java_mirror());
 825       }
 826       if (!have_name) {
 827         //not java_lang_String::create_from_symbol; let's intern member names
 828         oop name = StringTable::intern(m->name(), CHECK);
 829         java_lang_invoke_MemberName::set_name(mname(), name);
 830       }
 831       if (!have_type) {
 832         Handle type = java_lang_String::create_from_symbol(m->signature(), CHECK);
 833         java_lang_invoke_MemberName::set_type(mname(), type());
 834       }
 835       return;
 836     }
 837   case IS_FIELD:
 838     {
 839       oop clazz = java_lang_invoke_MemberName::clazz(mname());
 840       if (clazz == NULL) {
 841         THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "nothing to expand (as field)");
 842       }
 843       InstanceKlass* defc = InstanceKlass::cast(java_lang_Class::as_Klass(clazz));
 844       DEBUG_ONLY(clazz = NULL);  // safety
 845       int vmindex  = java_lang_invoke_MemberName::vmindex(mname());
 846       bool is_static = ((flags & JVM_ACC_STATIC) != 0);
 847       fieldDescriptor fd; // find_field initializes fd if found
 848       if (!defc->find_field_from_offset(vmindex, is_static, &fd))
 849         break;                  // cannot expand
 850       if (!have_name) {
 851         //not java_lang_String::create_from_symbol; let's intern member names
 852         oop name = StringTable::intern(fd.name(), CHECK);
 853         java_lang_invoke_MemberName::set_name(mname(), name);
 854       }
 855       if (!have_type) {
 856         // If it is a primitive field type, don't mess with short strings like "I".
 857         Handle type (THREAD, field_signature_type_or_null(fd.signature()));
 858         if (type.is_null()) {
 859           type = java_lang_String::create_from_symbol(fd.signature(), CHECK);
 860         }
 861         java_lang_invoke_MemberName::set_type(mname(), type());
 862       }
 863       return;
 864     }
 865   }
 866   THROW_MSG(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format");
 867 }
 868 
 869 int MethodHandles::find_MemberNames(Klass* k,
 870                                     Symbol* name, Symbol* sig,
 871                                     int mflags, Klass* caller,
 872                                     int skip, objArrayHandle results, TRAPS) {
 873   // %%% take caller into account!
 874 
 875   Thread* thread = Thread::current();
 876 
 877   if (k == NULL || !k->is_instance_klass())  return -1;
 878 
 879   int rfill = 0, rlimit = results->length(), rskip = skip;
 880   // overflow measurement:
 881   int overflow = 0, overflow_limit = MAX2(1000, rlimit);
 882 
 883   int match_flags = mflags;
 884   bool search_superc = ((match_flags & SEARCH_SUPERCLASSES) != 0);
 885   bool search_intfc  = ((match_flags & SEARCH_INTERFACES)   != 0);
 886   bool local_only = !(search_superc | search_intfc);
 887   bool classes_only = false;
 888 
 889   if (name != NULL) {
 890     if (name->utf8_length() == 0)  return 0; // a match is not possible
 891   }
 892   if (sig != NULL) {
 893     if (sig->utf8_length() == 0)  return 0; // a match is not possible
 894     if (sig->byte_at(0) == '(')
 895       match_flags &= ~(IS_FIELD | IS_TYPE);
 896     else
 897       match_flags &= ~(IS_CONSTRUCTOR | IS_METHOD);
 898   }
 899 
 900   if ((match_flags & IS_TYPE) != 0) {
 901     // NYI, and Core Reflection works quite well for this query
 902   }
 903 
 904   if ((match_flags & IS_FIELD) != 0) {
 905     InstanceKlass* ik = InstanceKlass::cast(k);
 906     for (FieldStream st(ik, local_only, !search_intfc); !st.eos(); st.next()) {
 907       if (name != NULL && st.name() != name)
 908           continue;
 909       if (sig != NULL && st.signature() != sig)
 910         continue;
 911       // passed the filters
 912       if (rskip > 0) {
 913         --rskip;
 914       } else if (rfill < rlimit) {
 915         Handle result(thread, results->obj_at(rfill++));
 916         if (!java_lang_invoke_MemberName::is_instance(result()))
 917           return -99;  // caller bug!
 918         oop saved = MethodHandles::init_field_MemberName(result, st.field_descriptor());
 919         if (saved != result())
 920           results->obj_at_put(rfill-1, saved);  // show saved instance to user
 921       } else if (++overflow >= overflow_limit) {
 922         match_flags = 0; break; // got tired of looking at overflow
 923       }
 924     }
 925   }
 926 
 927   if ((match_flags & (IS_METHOD | IS_CONSTRUCTOR)) != 0) {
 928     // watch out for these guys:
 929     Symbol* init_name   = vmSymbols::object_initializer_name();
 930     Symbol* clinit_name = vmSymbols::class_initializer_name();
 931     if (name == clinit_name)  clinit_name = NULL; // hack for exposing <clinit>
 932     bool negate_name_test = false;
 933     // fix name so that it captures the intention of IS_CONSTRUCTOR
 934     if (!(match_flags & IS_METHOD)) {
 935       // constructors only
 936       if (name == NULL) {
 937         name = init_name;
 938       } else if (name != init_name) {
 939         return 0;               // no constructors of this method name
 940       }
 941     } else if (!(match_flags & IS_CONSTRUCTOR)) {
 942       // methods only
 943       if (name == NULL) {
 944         name = init_name;
 945         negate_name_test = true; // if we see the name, we *omit* the entry
 946       } else if (name == init_name) {
 947         return 0;               // no methods of this constructor name
 948       }
 949     } else {
 950       // caller will accept either sort; no need to adjust name
 951     }
 952     InstanceKlass* ik = InstanceKlass::cast(k);
 953     for (MethodStream st(ik, local_only, !search_intfc); !st.eos(); st.next()) {
 954       Method* m = st.method();
 955       Symbol* m_name = m->name();
 956       if (m_name == clinit_name)
 957         continue;
 958       if (name != NULL && ((m_name != name) ^ negate_name_test))
 959           continue;
 960       if (sig != NULL && m->signature() != sig)
 961         continue;
 962       // passed the filters
 963       if (rskip > 0) {
 964         --rskip;
 965       } else if (rfill < rlimit) {
 966         Handle result(thread, results->obj_at(rfill++));
 967         if (!java_lang_invoke_MemberName::is_instance(result()))
 968           return -99;  // caller bug!
 969         CallInfo info(m, NULL, CHECK_0);
 970         oop saved = MethodHandles::init_method_MemberName(result, info);
 971         if (saved != result())
 972           results->obj_at_put(rfill-1, saved);  // show saved instance to user
 973       } else if (++overflow >= overflow_limit) {
 974         match_flags = 0; break; // got tired of looking at overflow
 975       }
 976     }
 977   }
 978 
 979   // return number of elements we at leasted wanted to initialize
 980   return rfill + overflow;
 981 }
 982 
 983 // Is it safe to remove stale entries from a dependency list?
 984 static bool safe_to_expunge() {
 985   // Since parallel GC threads can concurrently iterate over a dependency
 986   // list during safepoint, it is safe to remove entries only when
 987   // CodeCache lock is held.
 988   return CodeCache_lock->owned_by_self();
 989 }
 990 
 991 void MethodHandles::add_dependent_nmethod(oop call_site, nmethod* nm) {
 992   assert_locked_or_safepoint(CodeCache_lock);
 993 
 994   oop context = java_lang_invoke_CallSite::context(call_site);
 995   DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
 996   // Try to purge stale entries on updates.
 997   // Since GC doesn't clean dependency contexts rooted at CallSiteContext objects,
 998   // in order to avoid memory leak, stale entries are purged whenever a dependency list
 999   // is changed (both on addition and removal). Though memory reclamation is delayed,
1000   // it avoids indefinite memory usage growth.
1001   deps.add_dependent_nmethod(nm, /*expunge_stale_entries=*/safe_to_expunge());
1002 }
1003 
1004 void MethodHandles::remove_dependent_nmethod(oop call_site, nmethod* nm) {
1005   assert_locked_or_safepoint(CodeCache_lock);
1006 
1007   oop context = java_lang_invoke_CallSite::context(call_site);
1008   DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
1009   deps.remove_dependent_nmethod(nm, /*expunge_stale_entries=*/safe_to_expunge());
1010 }
1011 
1012 void MethodHandles::flush_dependent_nmethods(Handle call_site, Handle target) {
1013   assert_lock_strong(Compile_lock);
1014 
1015   int marked = 0;
1016   CallSiteDepChange changes(call_site, target);
1017   {
1018     NoSafepointVerifier nsv;
1019     MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1020 
1021     oop context = java_lang_invoke_CallSite::context(call_site());
1022     DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
1023     marked = deps.mark_dependent_nmethods(changes);
1024   }
1025   if (marked > 0) {
1026     // At least one nmethod has been marked for deoptimization.
1027     VM_Deoptimize op;
1028     VMThread::execute(&op);
1029   }
1030 }
1031 
1032 //
1033 // Here are the native methods in java.lang.invoke.MethodHandleNatives
1034 // They are the private interface between this JVM and the HotSpot-specific
1035 // Java code that implements JSR 292 method handles.
1036 //
1037 // Note:  We use a JVM_ENTRY macro to define each of these, for this is the way
1038 // that intrinsic (non-JNI) native methods are defined in HotSpot.
1039 //
1040 
1041 #ifndef PRODUCT
1042 #define EACH_NAMED_CON(template, requirement) \
1043     template(java_lang_invoke_MemberName,MN_IS_METHOD) \
1044     template(java_lang_invoke_MemberName,MN_IS_CONSTRUCTOR) \
1045     template(java_lang_invoke_MemberName,MN_IS_FIELD) \
1046     template(java_lang_invoke_MemberName,MN_IS_TYPE) \
1047     template(java_lang_invoke_MemberName,MN_CALLER_SENSITIVE) \
1048     template(java_lang_invoke_MemberName,MN_SEARCH_SUPERCLASSES) \
1049     template(java_lang_invoke_MemberName,MN_SEARCH_INTERFACES) \
1050     template(java_lang_invoke_MemberName,MN_REFERENCE_KIND_SHIFT) \
1051     template(java_lang_invoke_MemberName,MN_REFERENCE_KIND_MASK) \
1052     /*end*/
1053 
1054 #define IGNORE_REQ(req_expr) /* req_expr */
1055 #define ONE_PLUS(scope,value) 1+
1056 static const int con_value_count = EACH_NAMED_CON(ONE_PLUS, IGNORE_REQ) 0;
1057 #define VALUE_COMMA(scope,value) scope::value,
1058 static const int con_values[con_value_count+1] = { EACH_NAMED_CON(VALUE_COMMA, IGNORE_REQ) 0 };
1059 #define STRING_NULL(scope,value) #value "\0"
1060 static const char con_names[] = { EACH_NAMED_CON(STRING_NULL, IGNORE_REQ) };
1061 
1062 static bool advertise_con_value(int which) {
1063   if (which < 0)  return false;
1064   bool ok = true;
1065   int count = 0;
1066 #define INC_COUNT(scope,value) \
1067   ++count;
1068 #define CHECK_REQ(req_expr) \
1069   if (which < count)  return ok; \
1070   ok = (req_expr);
1071   EACH_NAMED_CON(INC_COUNT, CHECK_REQ);
1072 #undef INC_COUNT
1073 #undef CHECK_REQ
1074   assert(count == con_value_count, "");
1075   if (which < count)  return ok;
1076   return false;
1077 }
1078 
1079 #undef ONE_PLUS
1080 #undef VALUE_COMMA
1081 #undef STRING_NULL
1082 #undef EACH_NAMED_CON
1083 #endif // PRODUCT
1084 
1085 JVM_ENTRY(jint, MHN_getNamedCon(JNIEnv *env, jobject igcls, jint which, jobjectArray box_jh)) {
1086 #ifndef PRODUCT
1087   if (advertise_con_value(which)) {
1088     assert(which >= 0 && which < con_value_count, "");
1089     int con = con_values[which];
1090     objArrayHandle box(THREAD, (objArrayOop) JNIHandles::resolve(box_jh));
1091     if (box.not_null() && box->klass() == Universe::objectArrayKlassObj() && box->length() > 0) {
1092       const char* str = &con_names[0];
1093       for (int i = 0; i < which; i++)
1094         str += strlen(str) + 1;   // skip name and null
1095       oop name = java_lang_String::create_oop_from_str(str, CHECK_0);  // possible safepoint
1096       box->obj_at_put(0, name);
1097     }
1098     return con;
1099   }
1100 #endif
1101   return 0;
1102 }
1103 JVM_END
1104 
1105 // void init(MemberName self, AccessibleObject ref)
1106 JVM_ENTRY(void, MHN_init_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jobject target_jh)) {
1107   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
1108   if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
1109   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1110   Handle target(THREAD, JNIHandles::resolve_non_null(target_jh));
1111   MethodHandles::init_MemberName(mname, target, CHECK);
1112 }
1113 JVM_END
1114 
1115 // void expand(MemberName self)
1116 JVM_ENTRY(void, MHN_expand_Mem(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1117   if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
1118   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1119   MethodHandles::expand_MemberName(mname, 0, CHECK);
1120 }
1121 JVM_END
1122 
1123 // void resolve(MemberName self, Class<?> caller)
1124 JVM_ENTRY(jobject, MHN_resolve_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jclass caller_jh)) {
1125   if (mname_jh == NULL) { THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "mname is null"); }
1126   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1127 
1128   // The trusted Java code that calls this method should already have performed
1129   // access checks on behalf of the given caller.  But, we can verify this.
1130   if (VerifyMethodHandles && caller_jh != NULL &&
1131       java_lang_invoke_MemberName::clazz(mname()) != NULL) {
1132     Klass* reference_klass = java_lang_Class::as_Klass(java_lang_invoke_MemberName::clazz(mname()));
1133     if (reference_klass != NULL && reference_klass->is_objArray_klass()) {
1134       reference_klass = ObjArrayKlass::cast(reference_klass)->bottom_klass();
1135     }
1136 
1137     // Reflection::verify_class_access can only handle instance classes.
1138     if (reference_klass != NULL && reference_klass->is_instance_klass()) {
1139       // Emulate LinkResolver::check_klass_accessability.
1140       Klass* caller = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(caller_jh));
1141       if (caller != SystemDictionary::Object_klass()
1142           && Reflection::verify_class_access(caller,
1143                                              InstanceKlass::cast(reference_klass),
1144                                              true) != Reflection::ACCESS_OK) {
1145         THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), reference_klass->external_name());
1146       }
1147     }
1148   }
1149 
1150   Klass* caller = caller_jh == NULL ? NULL :
1151                      java_lang_Class::as_Klass(JNIHandles::resolve_non_null(caller_jh));
1152   Handle resolved = MethodHandles::resolve_MemberName(mname, caller, CHECK_NULL);
1153 
1154   if (resolved.is_null()) {
1155     int flags = java_lang_invoke_MemberName::flags(mname());
1156     int ref_kind = (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
1157     if (!MethodHandles::ref_kind_is_valid(ref_kind)) {
1158       THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "obsolete MemberName format");
1159     }
1160     if ((flags & ALL_KINDS) == IS_FIELD) {
1161       THROW_MSG_NULL(vmSymbols::java_lang_NoSuchFieldError(), "field resolution failed");
1162     } else if ((flags & ALL_KINDS) == IS_METHOD ||
1163                (flags & ALL_KINDS) == IS_CONSTRUCTOR) {
1164       THROW_MSG_NULL(vmSymbols::java_lang_NoSuchMethodError(), "method resolution failed");
1165     } else {
1166       THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "resolution failed");
1167     }
1168   }
1169 
1170   return JNIHandles::make_local(THREAD, resolved());
1171 }
1172 JVM_END
1173 
1174 static jlong find_member_field_offset(oop mname, bool must_be_static, TRAPS) {
1175   if (mname == NULL ||
1176       java_lang_invoke_MemberName::clazz(mname) == NULL) {
1177     THROW_MSG_0(vmSymbols::java_lang_InternalError(), "mname not resolved");
1178   } else {
1179     int flags = java_lang_invoke_MemberName::flags(mname);
1180     if ((flags & IS_FIELD) != 0 &&
1181         (must_be_static
1182          ? (flags & JVM_ACC_STATIC) != 0
1183          : (flags & JVM_ACC_STATIC) == 0)) {
1184       int vmindex = java_lang_invoke_MemberName::vmindex(mname);
1185       return (jlong) vmindex;
1186     }
1187   }
1188   const char* msg = (must_be_static ? "static field required" : "non-static field required");
1189   THROW_MSG_0(vmSymbols::java_lang_InternalError(), msg);
1190   return 0;
1191 }
1192 
1193 JVM_ENTRY(jlong, MHN_objectFieldOffset(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1194   return find_member_field_offset(JNIHandles::resolve(mname_jh), false, THREAD);
1195 }
1196 JVM_END
1197 
1198 JVM_ENTRY(jlong, MHN_staticFieldOffset(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1199   return find_member_field_offset(JNIHandles::resolve(mname_jh), true, THREAD);
1200 }
1201 JVM_END
1202 
1203 JVM_ENTRY(jobject, MHN_staticFieldBase(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1204   // use the other function to perform sanity checks:
1205   jlong ignore = find_member_field_offset(JNIHandles::resolve(mname_jh), true, CHECK_NULL);
1206   oop clazz = java_lang_invoke_MemberName::clazz(JNIHandles::resolve_non_null(mname_jh));
1207   return JNIHandles::make_local(THREAD, clazz);
1208 }
1209 JVM_END
1210 
1211 JVM_ENTRY(jobject, MHN_getMemberVMInfo(JNIEnv *env, jobject igcls, jobject mname_jh)) {
1212   if (mname_jh == NULL)  return NULL;
1213   Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
1214   intptr_t vmindex  = java_lang_invoke_MemberName::vmindex(mname());
1215   objArrayHandle result = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 2, CHECK_NULL);
1216   jvalue vmindex_value; vmindex_value.j = (long)vmindex;
1217   oop x = java_lang_boxing_object::create(T_LONG, &vmindex_value, CHECK_NULL);
1218   result->obj_at_put(0, x);
1219 
1220   int flags = java_lang_invoke_MemberName::flags(mname());
1221   if ((flags & IS_FIELD) != 0) {
1222     x = java_lang_invoke_MemberName::clazz(mname());
1223   } else {
1224     Method* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
1225     assert(vmtarget != NULL && vmtarget->is_method(), "vmtarget is only method");
1226     x = mname();
1227   }
1228   result->obj_at_put(1, x);
1229   return JNIHandles::make_local(env, result());
1230 }
1231 JVM_END
1232 
1233 
1234 
1235 //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
1236 //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
1237 JVM_ENTRY(jint, MHN_getMembers(JNIEnv *env, jobject igcls,
1238                                jclass clazz_jh, jstring name_jh, jstring sig_jh,
1239                                int mflags, jclass caller_jh, jint skip, jobjectArray results_jh)) {
1240   if (clazz_jh == NULL || results_jh == NULL)  return -1;
1241   Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz_jh));
1242 
1243   objArrayHandle results(THREAD, (objArrayOop) JNIHandles::resolve(results_jh));
1244   if (results.is_null() || !results->is_objArray())  return -1;
1245 
1246   TempNewSymbol name = NULL;
1247   TempNewSymbol sig = NULL;
1248   if (name_jh != NULL) {
1249     name = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(name_jh));
1250     if (name == NULL)  return 0; // a match is not possible
1251   }
1252   if (sig_jh != NULL) {
1253     sig = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(sig_jh));
1254     if (sig == NULL)  return 0; // a match is not possible
1255   }
1256 
1257   Klass* caller = NULL;
1258   if (caller_jh != NULL) {
1259     oop caller_oop = JNIHandles::resolve_non_null(caller_jh);
1260     if (!java_lang_Class::is_instance(caller_oop))  return -1;
1261     caller = java_lang_Class::as_Klass(caller_oop);
1262   }
1263 
1264   if (name != NULL && sig != NULL && results.not_null()) {
1265     // try a direct resolve
1266     // %%% TO DO
1267   }
1268 
1269   int res = MethodHandles::find_MemberNames(k, name, sig, mflags,
1270                                             caller, skip, results, CHECK_0);
1271   // TO DO: expand at least some of the MemberNames, to avoid massive callbacks
1272   return res;
1273 }
1274 JVM_END
1275 
1276 JVM_ENTRY(void, MHN_setCallSiteTargetNormal(JNIEnv* env, jobject igcls, jobject call_site_jh, jobject target_jh)) {
1277   Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
1278   Handle target   (THREAD, JNIHandles::resolve_non_null(target_jh));
1279   {
1280     // Walk all nmethods depending on this call site.
1281     MutexLocker mu(Compile_lock, thread);
1282     MethodHandles::flush_dependent_nmethods(call_site, target);
1283     java_lang_invoke_CallSite::set_target(call_site(), target());
1284   }
1285 }
1286 JVM_END
1287 
1288 JVM_ENTRY(void, MHN_setCallSiteTargetVolatile(JNIEnv* env, jobject igcls, jobject call_site_jh, jobject target_jh)) {
1289   Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
1290   Handle target   (THREAD, JNIHandles::resolve_non_null(target_jh));
1291   {
1292     // Walk all nmethods depending on this call site.
1293     MutexLocker mu(Compile_lock, thread);
1294     MethodHandles::flush_dependent_nmethods(call_site, target);
1295     java_lang_invoke_CallSite::set_target_volatile(call_site(), target());
1296   }
1297 }
1298 JVM_END
1299 
1300 // It is called by a Cleaner object which ensures that dropped CallSites properly
1301 // deallocate their dependency information.
1302 JVM_ENTRY(void, MHN_clearCallSiteContext(JNIEnv* env, jobject igcls, jobject context_jh)) {
1303   Handle context(THREAD, JNIHandles::resolve_non_null(context_jh));
1304   {
1305     // Walk all nmethods depending on this call site.
1306     MutexLocker mu1(Compile_lock, thread);
1307 
1308     int marked = 0;
1309     {
1310       NoSafepointVerifier nsv;
1311       MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1312       assert(safe_to_expunge(), "removal is not safe");
1313       DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context());
1314       marked = deps.remove_all_dependents();
1315     }
1316     if (marked > 0) {
1317       // At least one nmethod has been marked for deoptimization
1318       VM_Deoptimize op;
1319       VMThread::execute(&op);
1320     }
1321   }
1322 }
1323 JVM_END
1324 
1325 /**
1326  * Throws a java/lang/UnsupportedOperationException unconditionally.
1327  * This is required by the specification of MethodHandle.invoke if
1328  * invoked directly.
1329  */
1330 JVM_ENTRY(jobject, MH_invoke_UOE(JNIEnv* env, jobject mh, jobjectArray args)) {
1331   THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "MethodHandle.invoke cannot be invoked reflectively");
1332   return NULL;
1333 }
1334 JVM_END
1335 
1336 /**
1337  * Throws a java/lang/UnsupportedOperationException unconditionally.
1338  * This is required by the specification of MethodHandle.invokeExact if
1339  * invoked directly.
1340  */
1341 JVM_ENTRY(jobject, MH_invokeExact_UOE(JNIEnv* env, jobject mh, jobjectArray args)) {
1342   THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "MethodHandle.invokeExact cannot be invoked reflectively");
1343   return NULL;
1344 }
1345 JVM_END
1346 
1347 /// JVM_RegisterMethodHandleMethods
1348 
1349 #undef CS  // Solaris builds complain
1350 
1351 #define LANG "Ljava/lang/"
1352 #define JLINV "Ljava/lang/invoke/"
1353 
1354 #define OBJ   LANG "Object;"
1355 #define CLS   LANG "Class;"
1356 #define STRG  LANG "String;"
1357 #define CS    JLINV "CallSite;"
1358 #define MT    JLINV "MethodType;"
1359 #define MH    JLINV "MethodHandle;"
1360 #define MEM   JLINV "MemberName;"
1361 #define CTX   JLINV "MethodHandleNatives$CallSiteContext;"
1362 
1363 #define CC (char*)  /*cast a literal from (const char*)*/
1364 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1365 
1366 // These are the native methods on java.lang.invoke.MethodHandleNatives.
1367 static JNINativeMethod MHN_methods[] = {
1368   {CC "init",                      CC "(" MEM "" OBJ ")V",                   FN_PTR(MHN_init_Mem)},
1369   {CC "expand",                    CC "(" MEM ")V",                          FN_PTR(MHN_expand_Mem)},
1370   {CC "resolve",                   CC "(" MEM "" CLS ")" MEM,                FN_PTR(MHN_resolve_Mem)},
1371   //  static native int getNamedCon(int which, Object[] name)
1372   {CC "getNamedCon",               CC "(I[" OBJ ")I",                        FN_PTR(MHN_getNamedCon)},
1373   //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
1374   //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
1375   {CC "getMembers",                CC "(" CLS "" STRG "" STRG "I" CLS "I[" MEM ")I", FN_PTR(MHN_getMembers)},
1376   {CC "objectFieldOffset",         CC "(" MEM ")J",                          FN_PTR(MHN_objectFieldOffset)},
1377   {CC "setCallSiteTargetNormal",   CC "(" CS "" MH ")V",                     FN_PTR(MHN_setCallSiteTargetNormal)},
1378   {CC "setCallSiteTargetVolatile", CC "(" CS "" MH ")V",                     FN_PTR(MHN_setCallSiteTargetVolatile)},
1379   {CC "clearCallSiteContext",      CC "(" CTX ")V",                          FN_PTR(MHN_clearCallSiteContext)},
1380   {CC "staticFieldOffset",         CC "(" MEM ")J",                          FN_PTR(MHN_staticFieldOffset)},
1381   {CC "staticFieldBase",           CC "(" MEM ")" OBJ,                        FN_PTR(MHN_staticFieldBase)},
1382   {CC "getMemberVMInfo",           CC "(" MEM ")" OBJ,                        FN_PTR(MHN_getMemberVMInfo)}
1383 };
1384 
1385 static JNINativeMethod MH_methods[] = {
1386   // UnsupportedOperationException throwers
1387   {CC "invoke",                    CC "([" OBJ ")" OBJ,                       FN_PTR(MH_invoke_UOE)},
1388   {CC "invokeExact",               CC "([" OBJ ")" OBJ,                       FN_PTR(MH_invokeExact_UOE)}
1389 };
1390 
1391 /**
1392  * This one function is exported, used by NativeLookup.
1393  */
1394 JVM_ENTRY(void, JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass MHN_class)) {
1395   assert(!MethodHandles::enabled(), "must not be enabled");
1396   assert(SystemDictionary::MethodHandle_klass() != NULL, "should be present");
1397 
1398   oop mirror = SystemDictionary::MethodHandle_klass()->java_mirror();
1399   jclass MH_class = (jclass) JNIHandles::make_local(env, mirror);
1400 
1401   {
1402     ThreadToNativeFromVM ttnfv(thread);
1403 
1404     int status = env->RegisterNatives(MHN_class, MHN_methods, sizeof(MHN_methods)/sizeof(JNINativeMethod));
1405     guarantee(status == JNI_OK && !env->ExceptionOccurred(),
1406               "register java.lang.invoke.MethodHandleNative natives");
1407 
1408     status = env->RegisterNatives(MH_class, MH_methods, sizeof(MH_methods)/sizeof(JNINativeMethod));
1409     guarantee(status == JNI_OK && !env->ExceptionOccurred(),
1410               "register java.lang.invoke.MethodHandle natives");
1411   }
1412 
1413   if (TraceInvokeDynamic) {
1414     tty->print_cr("MethodHandle support loaded (using LambdaForms)");
1415   }
1416 
1417   MethodHandles::set_enabled(true);
1418 }
1419 JVM_END