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Java example source code file (linkResolver.hpp)

This example Java source code file (linkResolver.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

assert, bytecodes\:\:_getfield, bytecodes\:\:_putstatic, bytecodes\:\:code, callinfo, callinfo\:\:unknown_kind, callkind, cpce\:\:has_appendix, klasshandle, null, product_return, share_vm_interpreter_linkresolver_hpp, symbol, traps

The linkResolver.hpp Java example source code

/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#ifndef SHARE_VM_INTERPRETER_LINKRESOLVER_HPP
#define SHARE_VM_INTERPRETER_LINKRESOLVER_HPP

#include "oops/method.hpp"
#include "utilities/top.hpp"

// All the necessary definitions for run-time link resolution.

// CallInfo provides all the information gathered for a particular
// linked call site after resolving it. A link is any reference
// made from within the bytecodes of a method to an object outside of
// that method. If the info is invalid, the link has not been resolved
// successfully.

class CallInfo VALUE_OBJ_CLASS_SPEC {
 public:
  // Ways that a method call might be selected (or not) based on receiver type.
  // Note that an invokevirtual instruction might be linked with no_dispatch,
  // and an invokeinterface instruction might be linked with any of the three options
  enum CallKind {
    direct_call,                        // jump into resolved_method (must be concrete)
    vtable_call,                        // select recv.klass.method_at_vtable(index)
    itable_call,                        // select recv.klass.method_at_itable(resolved_method.holder, index)
    unknown_kind = -1
  };
 private:
  KlassHandle  _resolved_klass;         // static receiver klass, resolved from a symbolic reference
  KlassHandle  _selected_klass;         // dynamic receiver class (same as static, or subklass)
  methodHandle _resolved_method;        // static target method
  methodHandle _selected_method;        // dynamic (actual) target method
  CallKind     _call_kind;              // kind of call (static(=bytecode static/special +
                                        //               others inferred), vtable, itable)
  int          _call_index;             // vtable or itable index of selected class method (if any)
  Handle       _resolved_appendix;      // extra argument in constant pool (if CPCE::has_appendix)
  Handle       _resolved_method_type;   // MethodType (for invokedynamic and invokehandle call sites)

  void         set_static(   KlassHandle resolved_klass,                             methodHandle resolved_method                                                       , TRAPS);
  void         set_interface(KlassHandle resolved_klass, KlassHandle selected_klass, methodHandle resolved_method, methodHandle selected_method, int itable_index       , TRAPS);
  void         set_virtual(  KlassHandle resolved_klass, KlassHandle selected_klass, methodHandle resolved_method, methodHandle selected_method, int vtable_index       , TRAPS);
  void         set_handle(                                                           methodHandle resolved_method, Handle resolved_appendix, Handle resolved_method_type, TRAPS);
  void         set_common(   KlassHandle resolved_klass, KlassHandle selected_klass, methodHandle resolved_method, methodHandle selected_method, CallKind kind, int index, TRAPS);

  friend class LinkResolver;

 public:
  CallInfo() {
#ifndef PRODUCT
    _call_kind  = CallInfo::unknown_kind;
    _call_index = Method::garbage_vtable_index;
#endif //PRODUCT
  }

  // utility to extract an effective CallInfo from a method and an optional receiver limit
  // does not queue the method for compilation
  CallInfo(Method* resolved_method, Klass* resolved_klass = NULL);

  KlassHandle  resolved_klass() const            { return _resolved_klass; }
  KlassHandle  selected_klass() const            { return _selected_klass; }
  methodHandle resolved_method() const           { return _resolved_method; }
  methodHandle selected_method() const           { return _selected_method; }
  Handle       resolved_appendix() const         { return _resolved_appendix; }
  Handle       resolved_method_type() const      { return _resolved_method_type; }

  BasicType    result_type() const               { return selected_method()->result_type(); }
  CallKind     call_kind() const                 { return _call_kind; }
  int          call_index() const                { return _call_index; }
  int          vtable_index() const {
    // Even for interface calls the vtable index could be non-negative.
    // See CallInfo::set_interface.
    assert(has_vtable_index() || is_statically_bound(), "");
    assert(call_kind() == vtable_call || call_kind() == direct_call, "");
    // The returned value is < 0 if the call is statically bound.
    // But, the returned value may be >= 0 even if the kind is direct_call.
    // It is up to the caller to decide which way to go.
    return _call_index;
  }
  int          itable_index() const {
    assert(call_kind() == itable_call, "");
    // The returned value is always >= 0, a valid itable index.
    return _call_index;
  }

  // debugging
#ifdef ASSERT
  bool         has_vtable_index() const          { return _call_index >= 0 && _call_kind != CallInfo::itable_call; }
  bool         is_statically_bound() const       { return _call_index == Method::nonvirtual_vtable_index; }
#endif //ASSERT
  void         verify() PRODUCT_RETURN;
  void         print()  PRODUCT_RETURN;
};

// Link information for getfield/putfield & getstatic/putstatic bytecodes
// is represented using a fieldDescriptor.

// The LinkResolver is used to resolve constant-pool references at run-time.
// It does all necessary link-time checks & throws exceptions if necessary.

class LinkResolver: AllStatic {
  friend class klassVtable;
  friend class klassItable;

 private:
  static void lookup_method_in_klasses          (methodHandle& result, KlassHandle klass, Symbol* name, Symbol* signature, bool checkpolymorphism, bool in_imethod_resolve, TRAPS);
  static void lookup_instance_method_in_klasses (methodHandle& result, KlassHandle klass, Symbol* name, Symbol* signature, TRAPS);
  static void lookup_method_in_interfaces       (methodHandle& result, KlassHandle klass, Symbol* name, Symbol* signature, TRAPS);
  static void lookup_polymorphic_method         (methodHandle& result, KlassHandle klass, Symbol* name, Symbol* signature,
                                                 KlassHandle current_klass, Handle *appendix_result_or_null, Handle *method_type_result, TRAPS);

  static void resolve_klass           (KlassHandle& result, constantPoolHandle  pool, int index, TRAPS);

  static void resolve_pool  (KlassHandle& resolved_klass, Symbol*& method_name, Symbol*& method_signature, KlassHandle& current_klass, constantPoolHandle pool, int index, TRAPS);

  static void resolve_interface_method(methodHandle& resolved_method, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, bool nostatics, TRAPS);
  static void resolve_method          (methodHandle& resolved_method, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, bool require_methodref, TRAPS);

  static void linktime_resolve_static_method    (methodHandle& resolved_method, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, TRAPS);
  static void linktime_resolve_special_method   (methodHandle& resolved_method, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, TRAPS);
  static void linktime_resolve_virtual_method   (methodHandle &resolved_method, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature,KlassHandle current_klass, bool check_access, TRAPS);
  static void linktime_resolve_interface_method (methodHandle& resolved_method, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, TRAPS);

  static void runtime_resolve_special_method    (CallInfo& result, methodHandle resolved_method, KlassHandle resolved_klass, KlassHandle current_klass, bool check_access, TRAPS);
  static void runtime_resolve_virtual_method    (CallInfo& result, methodHandle resolved_method, KlassHandle resolved_klass, Handle recv, KlassHandle recv_klass, bool check_null_and_abstract, TRAPS);
  static void runtime_resolve_interface_method  (CallInfo& result, methodHandle resolved_method, KlassHandle resolved_klass, Handle recv, KlassHandle recv_klass, bool check_null_and_abstract, TRAPS);

  static void check_field_accessability   (KlassHandle ref_klass, KlassHandle resolved_klass, KlassHandle sel_klass, fieldDescriptor& fd, TRAPS);
  static void check_method_accessability  (KlassHandle ref_klass, KlassHandle resolved_klass, KlassHandle sel_klass, methodHandle sel_method, TRAPS);

 public:
  // constant pool resolving
  static void check_klass_accessability(KlassHandle ref_klass, KlassHandle sel_klass, TRAPS);

  // static resolving calls (will not run any Java code); used only from Bytecode_invoke::static_target
  static void resolve_method_statically(methodHandle& method_result, KlassHandle& klass_result,
                                        Bytecodes::Code code, constantPoolHandle pool, int index, TRAPS);

  // runtime/static resolving for fields
  static void resolve_field_access(fieldDescriptor& result, constantPoolHandle pool, int index, Bytecodes::Code byte, TRAPS);
  static void resolve_field(fieldDescriptor& result, KlassHandle resolved_klass, Symbol* field_name, Symbol* field_signature,
                            KlassHandle current_klass, Bytecodes::Code access_kind, bool check_access, bool initialize_class, TRAPS);

  // source of access_kind codes:
  static Bytecodes::Code field_access_kind(bool is_static, bool is_put) {
    return (is_static
            ? (is_put ? Bytecodes::_putstatic : Bytecodes::_getstatic)
            : (is_put ? Bytecodes::_putfield  : Bytecodes::_getfield ));
  }

  // runtime resolving:
  //   resolved_klass = specified class (i.e., static receiver class)
  //   current_klass  = sending method holder (i.e., class containing the method containing the call being resolved)
  static void resolve_static_call   (CallInfo& result,              KlassHandle& resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, bool initialize_klass, TRAPS);
  static void resolve_special_call  (CallInfo& result,              KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, TRAPS);
  static void resolve_virtual_call  (CallInfo& result, Handle recv, KlassHandle recv_klass, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, bool check_null_and_abstract, TRAPS);
  static void resolve_interface_call(CallInfo& result, Handle recv, KlassHandle recv_klass, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access, bool check_null_and_abstract, TRAPS);
  static void resolve_handle_call   (CallInfo& result,                                      KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, TRAPS);
  static void resolve_dynamic_call  (CallInfo& result,                                      Handle bootstrap_specifier, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, TRAPS);

  // same as above for compile-time resolution; but returns null handle instead of throwing an exception on error
  // also, does not initialize klass (i.e., no side effects)
  static methodHandle resolve_virtual_call_or_null  (KlassHandle receiver_klass, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass);
  static methodHandle resolve_interface_call_or_null(KlassHandle receiver_klass, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass);
  static methodHandle resolve_static_call_or_null   (KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass);
  static methodHandle resolve_special_call_or_null  (KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass);
  static int vtable_index_of_interface_method(KlassHandle klass, methodHandle resolved_method);

  // same as above for compile-time resolution; returns vtable_index if current_klass if linked
  static int resolve_virtual_vtable_index  (KlassHandle receiver_klass, KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass);

  // static resolving for compiler (does not throw exceptions, returns null handle if unsuccessful)
  static methodHandle linktime_resolve_virtual_method_or_null  (KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access);
  static methodHandle linktime_resolve_interface_method_or_null(KlassHandle resolved_klass, Symbol* method_name, Symbol* method_signature, KlassHandle current_klass, bool check_access);

  // runtime resolving from constant pool
  static void resolve_invokestatic   (CallInfo& result,              constantPoolHandle pool, int index, TRAPS);
  static void resolve_invokespecial  (CallInfo& result,              constantPoolHandle pool, int index, TRAPS);
  static void resolve_invokevirtual  (CallInfo& result, Handle recv, constantPoolHandle pool, int index, TRAPS);
  static void resolve_invokeinterface(CallInfo& result, Handle recv, constantPoolHandle pool, int index, TRAPS);
  static void resolve_invokedynamic  (CallInfo& result,              constantPoolHandle pool, int index, TRAPS);
  static void resolve_invokehandle   (CallInfo& result,              constantPoolHandle pool, int index, TRAPS);

  static void resolve_invoke         (CallInfo& result, Handle recv, constantPoolHandle pool, int index, Bytecodes::Code byte, TRAPS);
};

#endif // SHARE_VM_INTERPRETER_LINKRESOLVER_HPP

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