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  */
  24 
  25 class MacroAssembler;
  26 class Label;
  27 class MethodHandleEntry;
  28 
  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,
  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   // 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   }
 224 
 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   }
 242 
 243   static inline address from_compiled_entry(EntryKind ek);
 244   static inline address from_interpreted_entry(EntryKind ek);
 245 
 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);
 254 
 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);
 260 
 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 };
 273 
 274   // Generate MethodHandles adapters.
 275   static void generate_adapters();
 276 
 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);
 280 
 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);
 285 
 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,
 303 
 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);
 313 
 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   }
 344 
 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);
 349 
 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   }
 358 
 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   }
 362 
 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   }
 367 
 368   static const char* check_method_receiver(methodOop m, klassOop passed_recv_type);
 369 
 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);
 373 
 374   static void verify_method_type(methodHandle m, Handle mtype,
 375                                  bool has_bound_oop,
 376                                  KlassHandle bound_oop_type,
 377                                  TRAPS);
 378 
 379   static void verify_method_signature(methodHandle m, Handle mtype,
 380                                       int first_ptype_pos,
 381                                       KlassHandle insert_ptype, TRAPS);
 382 
 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);
 388 
 389  public:
 390 
 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);
 393 
 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);
 401 
 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);
 404 
 405 #ifdef ASSERT
 406   static bool spot_check_entry_names();
 407 #endif
 408 
 409  private:
 410   static methodHandle dispatch_decoded_method(methodHandle m,
 411                                               KlassHandle receiver_limit,
 412                                               int decode_flags,
 413                                               KlassHandle receiver_klass,
 414                                               TRAPS);
 415 
 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   }
 422 
 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);
 434 
 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 };
 440 
 441 
 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   };
 459 
 460   Data*     data()                              { return (Data*)this - 1; }
 461 
 462   address   start_address()                     { return (address) data(); }
 463   address   end_address()                       { return start_address() + data()->_total_size; }
 464 
 465   address   from_compiled_entry()               { return (address) this; }
 466 
 467   address   from_interpreted_entry()            { return data()->_from_interpreted_entry; }
 468   void  set_from_interpreted_entry(address e)   { data()->_from_interpreted_entry = e; }
 469 
 470   MethodHandleEntry* type_checking_entry()           { return data()->_type_checking_entry; }
 471   void set_type_checking_entry(MethodHandleEntry* e) { data()->_type_checking_entry = e; }
 472 
 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   }
 478 
 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   }
 486 
 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 };
 491 
 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(); }
 494 
 495 
 496 //------------------------------------------------------------------------------
 497 // MethodHandlesAdapterGenerator
 498 //
 499 class MethodHandlesAdapterGenerator : public StubCodeGenerator {
 500 public:
 501   MethodHandlesAdapterGenerator(CodeBuffer* code) : StubCodeGenerator(code) {}
 502 
 503   void generate();
 504 };