src/share/vm/prims/methodHandles.hpp

Fri, 30 Apr 2010 08:37:24 -0700

author
twisti
date
Fri, 30 Apr 2010 08:37:24 -0700
changeset 1861
2338d41fbd81
parent 1858
c640000b7cc1
child 1862
cd5dbf694d45
permissions
-rw-r--r--

6943304: remove tagged stack interpreter
Reviewed-by: coleenp, never, gbenson

     1 /*
     2  * Copyright 2008-2010 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 class MacroAssembler;
    26 class Label;
    27 class MethodHandleEntry;
    29 class MethodHandles: AllStatic {
    30   // JVM support for MethodHandle, MethodType, and related types
    31   // in java.dyn and java.dyn.hotspot.
    32   // See also  javaClasses for layouts java_dyn_Method{Handle,Type,Type::Form}.
    33  public:
    34   enum EntryKind {
    35     _raise_exception,           // stub for error generation from other stubs
    36     _invokestatic_mh,           // how a MH emulates invokestatic
    37     _invokespecial_mh,          // ditto for the other invokes...
    38     _invokevirtual_mh,
    39     _invokeinterface_mh,
    40     _bound_ref_mh,              // reference argument is bound
    41     _bound_int_mh,              // int argument is bound (via an Integer or Float)
    42     _bound_long_mh,             // long argument is bound (via a Long or Double)
    43     _bound_ref_direct_mh,       // same as above, with direct linkage to methodOop
    44     _bound_int_direct_mh,
    45     _bound_long_direct_mh,
    47     _adapter_mh_first,     // adapter sequence goes here...
    48     _adapter_retype_only   = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_RETYPE_ONLY,
    49     _adapter_retype_raw    = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_RETYPE_RAW,
    50     _adapter_check_cast    = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_CHECK_CAST,
    51     _adapter_prim_to_prim  = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_PRIM_TO_PRIM,
    52     _adapter_ref_to_prim   = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_REF_TO_PRIM,
    53     _adapter_prim_to_ref   = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_PRIM_TO_REF,
    54     _adapter_swap_args     = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_SWAP_ARGS,
    55     _adapter_rot_args      = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_ROT_ARGS,
    56     _adapter_dup_args      = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_DUP_ARGS,
    57     _adapter_drop_args     = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_DROP_ARGS,
    58     _adapter_collect_args  = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_COLLECT_ARGS,
    59     _adapter_spread_args   = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_SPREAD_ARGS,
    60     _adapter_flyby         = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_FLYBY,
    61     _adapter_ricochet      = _adapter_mh_first + sun_dyn_AdapterMethodHandle::OP_RICOCHET,
    62     _adapter_mh_last       = _adapter_mh_first + sun_dyn_AdapterMethodHandle::CONV_OP_LIMIT - 1,
    64     // Optimized adapter types
    66     // argument list reordering
    67     _adapter_opt_swap_1,
    68     _adapter_opt_swap_2,
    69     _adapter_opt_rot_1_up,
    70     _adapter_opt_rot_1_down,
    71     _adapter_opt_rot_2_up,
    72     _adapter_opt_rot_2_down,
    73     // primitive single to single:
    74     _adapter_opt_i2i,           // i2c, i2z, i2b, i2s
    75     // primitive double to single:
    76     _adapter_opt_l2i,
    77     _adapter_opt_d2f,
    78     // primitive single to double:
    79     _adapter_opt_i2l,
    80     _adapter_opt_f2d,
    81     // conversion between floating point and integer type is handled by Java
    83     // reference to primitive:
    84     _adapter_opt_unboxi,
    85     _adapter_opt_unboxl,
    87     // spreading (array length cases 0, 1, >=2)
    88     _adapter_opt_spread_0,
    89     _adapter_opt_spread_1,
    90     _adapter_opt_spread_more,
    92     _EK_LIMIT,
    93     _EK_FIRST = 0
    94   };
    96  public:
    97   static bool enabled()                         { return _enabled; }
    98   static void set_enabled(bool z);
   100  private:
   101   enum {  // import sun_dyn_AdapterMethodHandle::CONV_OP_*
   102     CONV_OP_LIMIT         = sun_dyn_AdapterMethodHandle::CONV_OP_LIMIT,
   103     CONV_OP_MASK          = sun_dyn_AdapterMethodHandle::CONV_OP_MASK,
   104     CONV_VMINFO_MASK      = sun_dyn_AdapterMethodHandle::CONV_VMINFO_MASK,
   105     CONV_VMINFO_SHIFT     = sun_dyn_AdapterMethodHandle::CONV_VMINFO_SHIFT,
   106     CONV_OP_SHIFT         = sun_dyn_AdapterMethodHandle::CONV_OP_SHIFT,
   107     CONV_DEST_TYPE_SHIFT  = sun_dyn_AdapterMethodHandle::CONV_DEST_TYPE_SHIFT,
   108     CONV_SRC_TYPE_SHIFT   = sun_dyn_AdapterMethodHandle::CONV_SRC_TYPE_SHIFT,
   109     CONV_STACK_MOVE_SHIFT = sun_dyn_AdapterMethodHandle::CONV_STACK_MOVE_SHIFT,
   110     CONV_STACK_MOVE_MASK  = sun_dyn_AdapterMethodHandle::CONV_STACK_MOVE_MASK
   111   };
   113   static bool _enabled;
   114   static MethodHandleEntry* _entries[_EK_LIMIT];
   115   static const char*        _entry_names[_EK_LIMIT+1];
   116   static jobject            _raise_exception_method;
   118   // Adapters.
   119   static MethodHandlesAdapterBlob* _adapter_code;
   120   static int                       _adapter_code_size;
   122   static bool ek_valid(EntryKind ek)            { return (uint)ek < (uint)_EK_LIMIT; }
   123   static bool conv_op_valid(int op)             { return (uint)op < (uint)CONV_OP_LIMIT; }
   125  public:
   126   static bool    have_entry(EntryKind ek)       { return ek_valid(ek) && _entries[ek] != NULL; }
   127   static MethodHandleEntry* entry(EntryKind ek) { assert(ek_valid(ek), "initialized");
   128                                                   return _entries[ek]; }
   129   static const char* entry_name(EntryKind ek)   { assert(ek_valid(ek), "oob");
   130                                                   return _entry_names[ek]; }
   131   static EntryKind adapter_entry_kind(int op)   { assert(conv_op_valid(op), "oob");
   132                                                   return EntryKind(_adapter_mh_first + op); }
   134   static void init_entry(EntryKind ek, MethodHandleEntry* me) {
   135     assert(ek_valid(ek), "oob");
   136     assert(_entries[ek] == NULL, "no double initialization");
   137     _entries[ek] = me;
   138   }
   140   // Some adapter helper functions.
   141   static void get_ek_bound_mh_info(EntryKind ek, BasicType& arg_type, int& arg_mask, int& arg_slots) {
   142     switch (ek) {
   143     case _bound_int_mh        : // fall-thru
   144     case _bound_int_direct_mh : arg_type = T_INT;    arg_mask = _INSERT_INT_MASK;  break;
   145     case _bound_long_mh       : // fall-thru
   146     case _bound_long_direct_mh: arg_type = T_LONG;   arg_mask = _INSERT_LONG_MASK; break;
   147     case _bound_ref_mh        : // fall-thru
   148     case _bound_ref_direct_mh : arg_type = T_OBJECT; arg_mask = _INSERT_REF_MASK;  break;
   149     default: ShouldNotReachHere();
   150     }
   151     arg_slots = type2size[arg_type];
   152   }
   154   static void get_ek_adapter_opt_swap_rot_info(EntryKind ek, int& swap_bytes, int& rotate) {
   155     int swap_slots = 0;
   156     switch (ek) {
   157     case _adapter_opt_swap_1:     swap_slots = 1; rotate =  0; break;
   158     case _adapter_opt_swap_2:     swap_slots = 2; rotate =  0; break;
   159     case _adapter_opt_rot_1_up:   swap_slots = 1; rotate =  1; break;
   160     case _adapter_opt_rot_1_down: swap_slots = 1; rotate = -1; break;
   161     case _adapter_opt_rot_2_up:   swap_slots = 2; rotate =  1; break;
   162     case _adapter_opt_rot_2_down: swap_slots = 2; rotate = -1; break;
   163     default: ShouldNotReachHere();
   164     }
   165     // Return the size of the stack slots to move in bytes.
   166     swap_bytes = swap_slots * Interpreter::stackElementSize;
   167   }
   169   static int get_ek_adapter_opt_spread_info(EntryKind ek) {
   170     switch (ek) {
   171     case _adapter_opt_spread_0: return  0;
   172     case _adapter_opt_spread_1: return  1;
   173     default                   : return -1;
   174     }
   175   }
   177   static methodOop raise_exception_method() {
   178     oop rem = JNIHandles::resolve(_raise_exception_method);
   179     assert(rem == NULL || rem->is_method(), "");
   180     return (methodOop) rem;
   181   }
   182   static void set_raise_exception_method(methodOop rem) {
   183     assert(_raise_exception_method == NULL, "");
   184     _raise_exception_method = JNIHandles::make_global(Handle(rem));
   185   }
   187   static jint adapter_conversion(int conv_op, BasicType src, BasicType dest,
   188                                  int stack_move = 0, int vminfo = 0) {
   189     assert(conv_op_valid(conv_op), "oob");
   190     jint conv = ((conv_op      << CONV_OP_SHIFT)
   191                  | (src        << CONV_SRC_TYPE_SHIFT)
   192                  | (dest       << CONV_DEST_TYPE_SHIFT)
   193                  | (stack_move << CONV_STACK_MOVE_SHIFT)
   194                  | (vminfo     << CONV_VMINFO_SHIFT)
   195                  );
   196     assert(adapter_conversion_op(conv) == conv_op, "decode conv_op");
   197     assert(adapter_conversion_src_type(conv) == src, "decode src");
   198     assert(adapter_conversion_dest_type(conv) == dest, "decode dest");
   199     assert(adapter_conversion_stack_move(conv) == stack_move, "decode stack_move");
   200     assert(adapter_conversion_vminfo(conv) == vminfo, "decode vminfo");
   201     return conv;
   202   }
   203   static int adapter_conversion_op(jint conv) {
   204     return ((conv >> CONV_OP_SHIFT) & 0xF);
   205   }
   206   static BasicType adapter_conversion_src_type(jint conv) {
   207     return (BasicType)((conv >> CONV_SRC_TYPE_SHIFT) & 0xF);
   208   }
   209   static BasicType adapter_conversion_dest_type(jint conv) {
   210     return (BasicType)((conv >> CONV_DEST_TYPE_SHIFT) & 0xF);
   211   }
   212   static int adapter_conversion_stack_move(jint conv) {
   213     return (conv >> CONV_STACK_MOVE_SHIFT);
   214   }
   215   static int adapter_conversion_vminfo(jint conv) {
   216     return (conv >> CONV_VMINFO_SHIFT) & CONV_VMINFO_MASK;
   217   }
   219   // Offset in words that the interpreter stack pointer moves when an argument is pushed.
   220   // The stack_move value must always be a multiple of this.
   221   static int stack_move_unit() {
   222     return frame::interpreter_frame_expression_stack_direction() * Interpreter::stackElementWords;
   223   }
   225   enum { CONV_VMINFO_SIGN_FLAG = 0x80 };
   226   static int adapter_subword_vminfo(BasicType dest) {
   227     if (dest == T_BOOLEAN) return (BitsPerInt -  1);
   228     if (dest == T_CHAR)    return (BitsPerInt - 16);
   229     if (dest == T_BYTE)    return (BitsPerInt -  8) | CONV_VMINFO_SIGN_FLAG;
   230     if (dest == T_SHORT)   return (BitsPerInt - 16) | CONV_VMINFO_SIGN_FLAG;
   231     return 0;                   // case T_INT
   232   }
   233   // Here is the transformation the i2i adapter must perform:
   234   static int truncate_subword_from_vminfo(jint value, int vminfo) {
   235     jint tem = value << vminfo;
   236     if ((vminfo & CONV_VMINFO_SIGN_FLAG) != 0) {
   237       return (jint)tem >> vminfo;
   238     } else {
   239       return (juint)tem >> vminfo;
   240     }
   241   }
   243   static inline address from_compiled_entry(EntryKind ek);
   244   static inline address from_interpreted_entry(EntryKind ek);
   246   // helpers for decode_method.
   247   static methodOop decode_methodOop(methodOop m, int& decode_flags_result);
   248   static methodOop decode_vmtarget(oop vmtarget, int vmindex, oop mtype, klassOop& receiver_limit_result, int& decode_flags_result);
   249   static methodOop decode_MemberName(oop mname, klassOop& receiver_limit_result, int& decode_flags_result);
   250   static methodOop decode_MethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
   251   static methodOop decode_DirectMethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
   252   static methodOop decode_BoundMethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
   253   static methodOop decode_AdapterMethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
   255   // Find out how many stack slots an mh pushes or pops.
   256   // The result is *not* reported as a multiple of stack_move_unit();
   257   // It is a signed net number of pushes (a difference in vmslots).
   258   // To compare with a stack_move value, first multiply by stack_move_unit().
   259   static int decode_MethodHandle_stack_pushes(oop mh);
   261  public:
   262   // working with member names
   263   static void resolve_MemberName(Handle mname, TRAPS); // compute vmtarget/vmindex from name/type
   264   static void expand_MemberName(Handle mname, int suppress, TRAPS);  // expand defc/name/type if missing
   265   static void init_MemberName(oop mname_oop, oop target); // compute vmtarget/vmindex from target
   266   static void init_MemberName(oop mname_oop, methodOop m, bool do_dispatch);
   267   static void init_MemberName(oop mname_oop, klassOop field_holder, AccessFlags mods, int offset);
   268   static int find_MemberNames(klassOop k, symbolOop name, symbolOop sig,
   269                               int mflags, klassOop caller,
   270                               int skip, objArrayOop results);
   271   // bit values for suppress argument to expand_MemberName:
   272   enum { _suppress_defc = 1, _suppress_name = 2, _suppress_type = 4 };
   274   // Generate MethodHandles adapters.
   275   static void generate_adapters();
   277   // Called from InterpreterGenerator and MethodHandlesAdapterGenerator.
   278   static address generate_method_handle_interpreter_entry(MacroAssembler* _masm);
   279   static void generate_method_handle_stub(MacroAssembler* _masm, EntryKind ek);
   281   // argument list parsing
   282   static int argument_slot(oop method_type, int arg);
   283   static int argument_slot_count(oop method_type) { return argument_slot(method_type, -1); }
   284   static int argument_slot_to_argnum(oop method_type, int argslot);
   286   // Runtime support
   287   enum {                        // bit-encoded flags from decode_method or decode_vmref
   288     _dmf_has_receiver   = 0x01, // target method has leading reference argument
   289     _dmf_does_dispatch  = 0x02, // method handle performs virtual or interface dispatch
   290     _dmf_from_interface = 0x04, // peforms interface dispatch
   291     _DMF_DIRECT_MASK    = (_dmf_from_interface*2 - _dmf_has_receiver),
   292     _dmf_binds_method   = 0x08,
   293     _dmf_binds_argument = 0x10,
   294     _DMF_BOUND_MASK     = (_dmf_binds_argument*2 - _dmf_binds_method),
   295     _dmf_adapter_lsb    = 0x20,
   296     _DMF_ADAPTER_MASK   = (_dmf_adapter_lsb << CONV_OP_LIMIT) - _dmf_adapter_lsb
   297   };
   298   static methodOop decode_method(oop x, klassOop& receiver_limit_result, int& decode_flags_result);
   299   enum {
   300     // format of query to getConstant:
   301     GC_JVM_PUSH_LIMIT = 0,
   302     GC_JVM_STACK_MOVE_UNIT = 1,
   304     // format of result from getTarget / encode_target:
   305     ETF_HANDLE_OR_METHOD_NAME = 0, // all available data (immediate MH or method)
   306     ETF_DIRECT_HANDLE         = 1, // ultimate method handle (will be a DMH, may be self)
   307     ETF_METHOD_NAME           = 2, // ultimate method as MemberName
   308     ETF_REFLECT_METHOD        = 3  // ultimate method as java.lang.reflect object (sans refClass)
   309   };
   310   static int get_named_constant(int which, Handle name_box, TRAPS);
   311   static oop encode_target(Handle mh, int format, TRAPS); // report vmtarget (to Java code)
   312   static bool class_cast_needed(klassOop src, klassOop dst);
   314  private:
   315   // These checkers operate on a pair of whole MethodTypes:
   316   static const char* check_method_type_change(oop src_mtype, int src_beg, int src_end,
   317                                               int insert_argnum, oop insert_type,
   318                                               int change_argnum, oop change_type,
   319                                               int delete_argnum,
   320                                               oop dst_mtype, int dst_beg, int dst_end,
   321                                               bool raw = false);
   322   static const char* check_method_type_insertion(oop src_mtype,
   323                                                  int insert_argnum, oop insert_type,
   324                                                  oop dst_mtype) {
   325     oop no_ref = NULL;
   326     return check_method_type_change(src_mtype, 0, -1,
   327                                     insert_argnum, insert_type,
   328                                     -1, no_ref, -1, dst_mtype, 0, -1);
   329   }
   330   static const char* check_method_type_conversion(oop src_mtype,
   331                                                   int change_argnum, oop change_type,
   332                                                   oop dst_mtype) {
   333     oop no_ref = NULL;
   334     return check_method_type_change(src_mtype, 0, -1, -1, no_ref,
   335                                     change_argnum, change_type,
   336                                     -1, dst_mtype, 0, -1);
   337   }
   338   static const char* check_method_type_passthrough(oop src_mtype, oop dst_mtype, bool raw) {
   339     oop no_ref = NULL;
   340     return check_method_type_change(src_mtype, 0, -1,
   341                                     -1, no_ref, -1, no_ref, -1,
   342                                     dst_mtype, 0, -1, raw);
   343   }
   345   // These checkers operate on pairs of argument or return types:
   346   static const char* check_argument_type_change(BasicType src_type, klassOop src_klass,
   347                                                 BasicType dst_type, klassOop dst_klass,
   348                                                 int argnum, bool raw = false);
   350   static const char* check_argument_type_change(oop src_type, oop dst_type,
   351                                                 int argnum, bool raw = false) {
   352     klassOop src_klass = NULL, dst_klass = NULL;
   353     BasicType src_bt = java_lang_Class::as_BasicType(src_type, &src_klass);
   354     BasicType dst_bt = java_lang_Class::as_BasicType(dst_type, &dst_klass);
   355     return check_argument_type_change(src_bt, src_klass,
   356                                       dst_bt, dst_klass, argnum, raw);
   357   }
   359   static const char* check_return_type_change(oop src_type, oop dst_type, bool raw = false) {
   360     return check_argument_type_change(src_type, dst_type, -1, raw);
   361   }
   363   static const char* check_return_type_change(BasicType src_type, klassOop src_klass,
   364                                               BasicType dst_type, klassOop dst_klass) {
   365     return check_argument_type_change(src_type, src_klass, dst_type, dst_klass, -1);
   366   }
   368   static const char* check_method_receiver(methodOop m, klassOop passed_recv_type);
   370   // These verifiers can block, and will throw an error if the checking fails:
   371   static void verify_vmslots(Handle mh, TRAPS);
   372   static void verify_vmargslot(Handle mh, int argnum, int argslot, TRAPS);
   374   static void verify_method_type(methodHandle m, Handle mtype,
   375                                  bool has_bound_oop,
   376                                  KlassHandle bound_oop_type,
   377                                  TRAPS);
   379   static void verify_method_signature(methodHandle m, Handle mtype,
   380                                       int first_ptype_pos,
   381                                       KlassHandle insert_ptype, TRAPS);
   383   static void verify_DirectMethodHandle(Handle mh, methodHandle m, TRAPS);
   384   static void verify_BoundMethodHandle(Handle mh, Handle target, int argnum,
   385                                        bool direct_to_method, TRAPS);
   386   static void verify_BoundMethodHandle_with_receiver(Handle mh, methodHandle m, TRAPS);
   387   static void verify_AdapterMethodHandle(Handle mh, int argnum, TRAPS);
   389  public:
   391   // Fill in the fields of a DirectMethodHandle mh.  (MH.type must be pre-filled.)
   392   static void init_DirectMethodHandle(Handle mh, methodHandle method, bool do_dispatch, TRAPS);
   394   // Fill in the fields of a BoundMethodHandle mh.  (MH.type, BMH.argument must be pre-filled.)
   395   static void init_BoundMethodHandle(Handle mh, Handle target, int argnum, TRAPS);
   396   static void init_BoundMethodHandle_with_receiver(Handle mh,
   397                                                    methodHandle original_m,
   398                                                    KlassHandle receiver_limit,
   399                                                    int decode_flags,
   400                                                    TRAPS);
   402   // Fill in the fields of an AdapterMethodHandle mh.  (MH.type must be pre-filled.)
   403   static void init_AdapterMethodHandle(Handle mh, Handle target, int argnum, TRAPS);
   405 #ifdef ASSERT
   406   static bool spot_check_entry_names();
   407 #endif
   409  private:
   410   static methodHandle dispatch_decoded_method(methodHandle m,
   411                                               KlassHandle receiver_limit,
   412                                               int decode_flags,
   413                                               KlassHandle receiver_klass,
   414                                               TRAPS);
   416   static bool same_basic_type_for_arguments(BasicType src, BasicType dst,
   417                                             bool raw = false,
   418                                             bool for_return = false);
   419   static bool same_basic_type_for_returns(BasicType src, BasicType dst, bool raw = false) {
   420     return same_basic_type_for_arguments(src, dst, raw, true);
   421   }
   423   enum {                        // arg_mask values
   424     _INSERT_NO_MASK   = -1,
   425     _INSERT_REF_MASK  = 0,
   426     _INSERT_INT_MASK  = 1,
   427     _INSERT_LONG_MASK = 3
   428   };
   429   static void insert_arg_slots(MacroAssembler* _masm,
   430                                RegisterOrConstant arg_slots,
   431                                int arg_mask,
   432                                Register argslot_reg,
   433                                Register temp_reg, Register temp2_reg, Register temp3_reg = noreg);
   435   static void remove_arg_slots(MacroAssembler* _masm,
   436                                RegisterOrConstant arg_slots,
   437                                Register argslot_reg,
   438                                Register temp_reg, Register temp2_reg, Register temp3_reg = noreg);
   439 };
   442 // Access methods for the "entry" field of a java.dyn.MethodHandle.
   443 // The field is primarily a jump target for compiled calls.
   444 // However, we squirrel away some nice pointers for other uses,
   445 // just before the jump target.
   446 // Aspects of a method handle entry:
   447 //  - from_compiled_entry - stub used when compiled code calls the MH
   448 //  - from_interpreted_entry - stub used when the interpreter calls the MH
   449 //  - type_checking_entry - stub for runtime casting between MHForm siblings (NYI)
   450 class MethodHandleEntry {
   451  public:
   452   class Data {
   453     friend class MethodHandleEntry;
   454     size_t              _total_size; // size including Data and code stub
   455     MethodHandleEntry*  _type_checking_entry;
   456     address             _from_interpreted_entry;
   457     MethodHandleEntry* method_entry() { return (MethodHandleEntry*)(this + 1); }
   458   };
   460   Data*     data()                              { return (Data*)this - 1; }
   462   address   start_address()                     { return (address) data(); }
   463   address   end_address()                       { return start_address() + data()->_total_size; }
   465   address   from_compiled_entry()               { return (address) this; }
   467   address   from_interpreted_entry()            { return data()->_from_interpreted_entry; }
   468   void  set_from_interpreted_entry(address e)   { data()->_from_interpreted_entry = e; }
   470   MethodHandleEntry* type_checking_entry()           { return data()->_type_checking_entry; }
   471   void set_type_checking_entry(MethodHandleEntry* e) { data()->_type_checking_entry = e; }
   473   void set_end_address(address end_addr) {
   474     size_t total_size = end_addr - start_address();
   475     assert(total_size > 0 && total_size < 0x1000, "reasonable end address");
   476     data()->_total_size = total_size;
   477   }
   479   // Compiler support:
   480   static int from_interpreted_entry_offset_in_bytes() {
   481     return (int)( offset_of(Data, _from_interpreted_entry) - sizeof(Data) );
   482   }
   483   static int type_checking_entry_offset_in_bytes() {
   484     return (int)( offset_of(Data, _from_interpreted_entry) - sizeof(Data) );
   485   }
   487   static address            start_compiled_entry(MacroAssembler* _masm,
   488                                                  address interpreted_entry = NULL);
   489   static MethodHandleEntry* finish_compiled_entry(MacroAssembler* masm, address start_addr);
   490 };
   492 address MethodHandles::from_compiled_entry(EntryKind ek) { return entry(ek)->from_compiled_entry(); }
   493 address MethodHandles::from_interpreted_entry(EntryKind ek) { return entry(ek)->from_interpreted_entry(); }
   496 //------------------------------------------------------------------------------
   497 // MethodHandlesAdapterGenerator
   498 //
   499 class MethodHandlesAdapterGenerator : public StubCodeGenerator {
   500 public:
   501   MethodHandlesAdapterGenerator(CodeBuffer* code) : StubCodeGenerator(code) {}
   503   void generate();
   504 };

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