methodHandles.hpp revision 1472:c18cbe5936b8
1/*
2 * Copyright (c) 2008, 2010, 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
25class MacroAssembler;
26class Label;
27class MethodHandleEntry;
28
29class 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,
46
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,
63
64    // Optimized adapter types
65
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
82
83    // reference to primitive:
84    _adapter_opt_unboxi,
85    _adapter_opt_unboxl,
86
87    // spreading (array length cases 0, 1, >=2)
88    _adapter_opt_spread_0,
89    _adapter_opt_spread_1,
90    _adapter_opt_spread_more,
91
92    _EK_LIMIT,
93    _EK_FIRST = 0
94  };
95
96 public:
97  static bool enabled()                         { return _enabled; }
98  static void set_enabled(bool z);
99
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  };
112
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;
117
118  // Adapters.
119  static MethodHandlesAdapterBlob* _adapter_code;
120  static int                       _adapter_code_size;
121
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; }
124
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); }
133
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  }
139
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  }
153
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  }
168
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  }
176
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  }
186
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  }
218
219  // Bit mask of conversion_op values.  May vary by platform.
220  static int adapter_conversion_ops_supported_mask();
221
222  // Offset in words that the interpreter stack pointer moves when an argument is pushed.
223  // The stack_move value must always be a multiple of this.
224  static int stack_move_unit() {
225    return frame::interpreter_frame_expression_stack_direction() * Interpreter::stackElementWords;
226  }
227
228  enum { CONV_VMINFO_SIGN_FLAG = 0x80 };
229  static int adapter_subword_vminfo(BasicType dest) {
230    if (dest == T_BOOLEAN) return (BitsPerInt -  1);
231    if (dest == T_CHAR)    return (BitsPerInt - 16);
232    if (dest == T_BYTE)    return (BitsPerInt -  8) | CONV_VMINFO_SIGN_FLAG;
233    if (dest == T_SHORT)   return (BitsPerInt - 16) | CONV_VMINFO_SIGN_FLAG;
234    return 0;                   // case T_INT
235  }
236  // Here is the transformation the i2i adapter must perform:
237  static int truncate_subword_from_vminfo(jint value, int vminfo) {
238    jint tem = value << vminfo;
239    if ((vminfo & CONV_VMINFO_SIGN_FLAG) != 0) {
240      return (jint)tem >> vminfo;
241    } else {
242      return (juint)tem >> vminfo;
243    }
244  }
245
246  static inline address from_compiled_entry(EntryKind ek);
247  static inline address from_interpreted_entry(EntryKind ek);
248
249  // helpers for decode_method.
250  static methodOop decode_methodOop(methodOop m, int& decode_flags_result);
251  static methodOop decode_vmtarget(oop vmtarget, int vmindex, oop mtype, klassOop& receiver_limit_result, int& decode_flags_result);
252  static methodOop decode_MemberName(oop mname, klassOop& receiver_limit_result, int& decode_flags_result);
253  static methodOop decode_MethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
254  static methodOop decode_DirectMethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
255  static methodOop decode_BoundMethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
256  static methodOop decode_AdapterMethodHandle(oop mh, klassOop& receiver_limit_result, int& decode_flags_result);
257
258  // Find out how many stack slots an mh pushes or pops.
259  // The result is *not* reported as a multiple of stack_move_unit();
260  // It is a signed net number of pushes (a difference in vmslots).
261  // To compare with a stack_move value, first multiply by stack_move_unit().
262  static int decode_MethodHandle_stack_pushes(oop mh);
263
264 public:
265  // working with member names
266  static void resolve_MemberName(Handle mname, TRAPS); // compute vmtarget/vmindex from name/type
267  static void expand_MemberName(Handle mname, int suppress, TRAPS);  // expand defc/name/type if missing
268  static Handle new_MemberName(TRAPS);  // must be followed by init_MemberName
269  static void init_MemberName(oop mname_oop, oop target); // compute vmtarget/vmindex from target
270  static void init_MemberName(oop mname_oop, methodOop m, bool do_dispatch = true);
271  static void init_MemberName(oop mname_oop, klassOop field_holder, AccessFlags mods, int offset);
272  static int find_MemberNames(klassOop k, symbolOop name, symbolOop sig,
273                              int mflags, klassOop caller,
274                              int skip, objArrayOop results);
275  // bit values for suppress argument to expand_MemberName:
276  enum { _suppress_defc = 1, _suppress_name = 2, _suppress_type = 4 };
277
278  // Generate MethodHandles adapters.
279  static void generate_adapters();
280
281  // Called from InterpreterGenerator and MethodHandlesAdapterGenerator.
282  static address generate_method_handle_interpreter_entry(MacroAssembler* _masm);
283  static void generate_method_handle_stub(MacroAssembler* _masm, EntryKind ek);
284
285  // argument list parsing
286  static int argument_slot(oop method_type, int arg);
287  static int argument_slot_count(oop method_type) { return argument_slot(method_type, -1); }
288  static int argument_slot_to_argnum(oop method_type, int argslot);
289
290  // Runtime support
291  enum {                        // bit-encoded flags from decode_method or decode_vmref
292    _dmf_has_receiver   = 0x01, // target method has leading reference argument
293    _dmf_does_dispatch  = 0x02, // method handle performs virtual or interface dispatch
294    _dmf_from_interface = 0x04, // peforms interface dispatch
295    _DMF_DIRECT_MASK    = (_dmf_from_interface*2 - _dmf_has_receiver),
296    _dmf_binds_method   = 0x08,
297    _dmf_binds_argument = 0x10,
298    _DMF_BOUND_MASK     = (_dmf_binds_argument*2 - _dmf_binds_method),
299    _dmf_adapter_lsb    = 0x20,
300    _DMF_ADAPTER_MASK   = (_dmf_adapter_lsb << CONV_OP_LIMIT) - _dmf_adapter_lsb
301  };
302  static methodOop decode_method(oop x, klassOop& receiver_limit_result, int& decode_flags_result);
303  enum {
304    // format of query to getConstant:
305    GC_JVM_PUSH_LIMIT = 0,
306    GC_JVM_STACK_MOVE_UNIT = 1,
307    GC_CONV_OP_IMPLEMENTED_MASK = 2,
308
309    // format of result from getTarget / encode_target:
310    ETF_HANDLE_OR_METHOD_NAME = 0, // all available data (immediate MH or method)
311    ETF_DIRECT_HANDLE         = 1, // ultimate method handle (will be a DMH, may be self)
312    ETF_METHOD_NAME           = 2, // ultimate method as MemberName
313    ETF_REFLECT_METHOD        = 3  // ultimate method as java.lang.reflect object (sans refClass)
314  };
315  static int get_named_constant(int which, Handle name_box, TRAPS);
316  static oop encode_target(Handle mh, int format, TRAPS); // report vmtarget (to Java code)
317  static bool class_cast_needed(klassOop src, klassOop dst);
318
319  static instanceKlassHandle resolve_instance_klass(oop    java_mirror_oop, TRAPS);
320  static instanceKlassHandle resolve_instance_klass(jclass java_mirror_jh,  TRAPS) {
321    return resolve_instance_klass(JNIHandles::resolve(java_mirror_jh), THREAD);
322  }
323
324 private:
325  // These checkers operate on a pair of whole MethodTypes:
326  static const char* check_method_type_change(oop src_mtype, int src_beg, int src_end,
327                                              int insert_argnum, oop insert_type,
328                                              int change_argnum, oop change_type,
329                                              int delete_argnum,
330                                              oop dst_mtype, int dst_beg, int dst_end,
331                                              bool raw = false);
332  static const char* check_method_type_insertion(oop src_mtype,
333                                                 int insert_argnum, oop insert_type,
334                                                 oop dst_mtype) {
335    oop no_ref = NULL;
336    return check_method_type_change(src_mtype, 0, -1,
337                                    insert_argnum, insert_type,
338                                    -1, no_ref, -1, dst_mtype, 0, -1);
339  }
340  static const char* check_method_type_conversion(oop src_mtype,
341                                                  int change_argnum, oop change_type,
342                                                  oop dst_mtype) {
343    oop no_ref = NULL;
344    return check_method_type_change(src_mtype, 0, -1, -1, no_ref,
345                                    change_argnum, change_type,
346                                    -1, dst_mtype, 0, -1);
347  }
348  static const char* check_method_type_passthrough(oop src_mtype, oop dst_mtype, bool raw) {
349    oop no_ref = NULL;
350    return check_method_type_change(src_mtype, 0, -1,
351                                    -1, no_ref, -1, no_ref, -1,
352                                    dst_mtype, 0, -1, raw);
353  }
354
355  // These checkers operate on pairs of argument or return types:
356  static const char* check_argument_type_change(BasicType src_type, klassOop src_klass,
357                                                BasicType dst_type, klassOop dst_klass,
358                                                int argnum, bool raw = false);
359
360  static const char* check_argument_type_change(oop src_type, oop dst_type,
361                                                int argnum, bool raw = false) {
362    klassOop src_klass = NULL, dst_klass = NULL;
363    BasicType src_bt = java_lang_Class::as_BasicType(src_type, &src_klass);
364    BasicType dst_bt = java_lang_Class::as_BasicType(dst_type, &dst_klass);
365    return check_argument_type_change(src_bt, src_klass,
366                                      dst_bt, dst_klass, argnum, raw);
367  }
368
369  static const char* check_return_type_change(oop src_type, oop dst_type, bool raw = false) {
370    return check_argument_type_change(src_type, dst_type, -1, raw);
371  }
372
373  static const char* check_return_type_change(BasicType src_type, klassOop src_klass,
374                                              BasicType dst_type, klassOop dst_klass) {
375    return check_argument_type_change(src_type, src_klass, dst_type, dst_klass, -1);
376  }
377
378  static const char* check_method_receiver(methodOop m, klassOop passed_recv_type);
379
380  // These verifiers can block, and will throw an error if the checking fails:
381  static void verify_vmslots(Handle mh, TRAPS);
382  static void verify_vmargslot(Handle mh, int argnum, int argslot, TRAPS);
383
384  static void verify_method_type(methodHandle m, Handle mtype,
385                                 bool has_bound_oop,
386                                 KlassHandle bound_oop_type,
387                                 TRAPS);
388
389  static void verify_method_signature(methodHandle m, Handle mtype,
390                                      int first_ptype_pos,
391                                      KlassHandle insert_ptype, TRAPS);
392
393  static void verify_DirectMethodHandle(Handle mh, methodHandle m, TRAPS);
394  static void verify_BoundMethodHandle(Handle mh, Handle target, int argnum,
395                                       bool direct_to_method, TRAPS);
396  static void verify_BoundMethodHandle_with_receiver(Handle mh, methodHandle m, TRAPS);
397  static void verify_AdapterMethodHandle(Handle mh, int argnum, TRAPS);
398
399 public:
400
401  // Fill in the fields of a DirectMethodHandle mh.  (MH.type must be pre-filled.)
402  static void init_DirectMethodHandle(Handle mh, methodHandle method, bool do_dispatch, TRAPS);
403
404  // Fill in the fields of a BoundMethodHandle mh.  (MH.type, BMH.argument must be pre-filled.)
405  static void init_BoundMethodHandle(Handle mh, Handle target, int argnum, TRAPS);
406  static void init_BoundMethodHandle_with_receiver(Handle mh,
407                                                   methodHandle original_m,
408                                                   KlassHandle receiver_limit,
409                                                   int decode_flags,
410                                                   TRAPS);
411
412  // Fill in the fields of an AdapterMethodHandle mh.  (MH.type must be pre-filled.)
413  static void init_AdapterMethodHandle(Handle mh, Handle target, int argnum, TRAPS);
414
415#ifdef ASSERT
416  static bool spot_check_entry_names();
417#endif
418
419 private:
420  static methodHandle dispatch_decoded_method(methodHandle m,
421                                              KlassHandle receiver_limit,
422                                              int decode_flags,
423                                              KlassHandle receiver_klass,
424                                              TRAPS);
425
426  static bool same_basic_type_for_arguments(BasicType src, BasicType dst,
427                                            bool raw = false,
428                                            bool for_return = false);
429  static bool same_basic_type_for_returns(BasicType src, BasicType dst, bool raw = false) {
430    return same_basic_type_for_arguments(src, dst, raw, true);
431  }
432
433  enum {                        // arg_mask values
434    _INSERT_NO_MASK   = -1,
435    _INSERT_REF_MASK  = 0,
436    _INSERT_INT_MASK  = 1,
437    _INSERT_LONG_MASK = 3
438  };
439  static void insert_arg_slots(MacroAssembler* _masm,
440                               RegisterOrConstant arg_slots,
441                               int arg_mask,
442                               Register argslot_reg,
443                               Register temp_reg, Register temp2_reg, Register temp3_reg = noreg);
444
445  static void remove_arg_slots(MacroAssembler* _masm,
446                               RegisterOrConstant arg_slots,
447                               Register argslot_reg,
448                               Register temp_reg, Register temp2_reg, Register temp3_reg = noreg);
449};
450
451
452// Access methods for the "entry" field of a java.dyn.MethodHandle.
453// The field is primarily a jump target for compiled calls.
454// However, we squirrel away some nice pointers for other uses,
455// just before the jump target.
456// Aspects of a method handle entry:
457//  - from_compiled_entry - stub used when compiled code calls the MH
458//  - from_interpreted_entry - stub used when the interpreter calls the MH
459//  - type_checking_entry - stub for runtime casting between MHForm siblings (NYI)
460class MethodHandleEntry {
461 public:
462  class Data {
463    friend class MethodHandleEntry;
464    size_t              _total_size; // size including Data and code stub
465    MethodHandleEntry*  _type_checking_entry;
466    address             _from_interpreted_entry;
467    MethodHandleEntry* method_entry() { return (MethodHandleEntry*)(this + 1); }
468  };
469
470  Data*     data()                              { return (Data*)this - 1; }
471
472  address   start_address()                     { return (address) data(); }
473  address   end_address()                       { return start_address() + data()->_total_size; }
474
475  address   from_compiled_entry()               { return (address) this; }
476
477  address   from_interpreted_entry()            { return data()->_from_interpreted_entry; }
478  void  set_from_interpreted_entry(address e)   { data()->_from_interpreted_entry = e; }
479
480  MethodHandleEntry* type_checking_entry()           { return data()->_type_checking_entry; }
481  void set_type_checking_entry(MethodHandleEntry* e) { data()->_type_checking_entry = e; }
482
483  void set_end_address(address end_addr) {
484    size_t total_size = end_addr - start_address();
485    assert(total_size > 0 && total_size < 0x1000, "reasonable end address");
486    data()->_total_size = total_size;
487  }
488
489  // Compiler support:
490  static int from_interpreted_entry_offset_in_bytes() {
491    return (int)( offset_of(Data, _from_interpreted_entry) - sizeof(Data) );
492  }
493  static int type_checking_entry_offset_in_bytes() {
494    return (int)( offset_of(Data, _from_interpreted_entry) - sizeof(Data) );
495  }
496
497  static address            start_compiled_entry(MacroAssembler* _masm,
498                                                 address interpreted_entry = NULL);
499  static MethodHandleEntry* finish_compiled_entry(MacroAssembler* masm, address start_addr);
500};
501
502address MethodHandles::from_compiled_entry(EntryKind ek) { return entry(ek)->from_compiled_entry(); }
503address MethodHandles::from_interpreted_entry(EntryKind ek) { return entry(ek)->from_interpreted_entry(); }
504
505
506//------------------------------------------------------------------------------
507// MethodHandlesAdapterGenerator
508//
509class MethodHandlesAdapterGenerator : public StubCodeGenerator {
510public:
511  MethodHandlesAdapterGenerator(CodeBuffer* code) : StubCodeGenerator(code) {}
512
513  void generate();
514};
515