1 /*

     2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #include "precompiled.hpp"

    26 #include "interp_masm_x86.hpp"

    27 #include "interpreter/interpreter.hpp"

    28 #include "interpreter/interpreterRuntime.hpp"

    29 #include "oops/arrayOop.hpp"

    30 #include "oops/markOop.hpp"

    31 #include "oops/methodData.hpp"

    32 #include "oops/method.hpp"

    33 #include "prims/jvmtiExport.hpp"

    34 #include "prims/jvmtiRedefineClassesTrace.hpp"

    35 #include "prims/jvmtiThreadState.hpp"

    36 #include "runtime/basicLock.hpp"

    37 #include "runtime/biasedLocking.hpp"

    38 #include "runtime/sharedRuntime.hpp"

    39 #include "runtime/thread.inline.hpp"

    40 

    41 

    42 // Implementation of InterpreterMacroAssembler

    43 #ifdef CC_INTERP

    44 void InterpreterMacroAssembler::get_method(Register reg) {

    45   movptr(reg, Address(rbp, -(sizeof(BytecodeInterpreter) + 2 * wordSize)));

    46   movptr(reg, Address(reg, byte_offset_of(BytecodeInterpreter, _method)));

    47 }

    48 #endif // CC_INTERP

    49 

    50 

    51 #ifndef CC_INTERP

    52 void InterpreterMacroAssembler::call_VM_leaf_base(

    53   address entry_point,

    54   int     number_of_arguments

    55 ) {

    56   // interpreter specific

    57   //

    58   // Note: No need to save/restore bcp & locals (rsi & rdi) pointer

    59   //       since these are callee saved registers and no blocking/

    60   //       GC can happen in leaf calls.

    61   // Further Note: DO NOT save/restore bcp/locals. If a caller has

    62   // already saved them so that it can use rsi/rdi as temporaries

    63   // then a save/restore here will DESTROY the copy the caller

    64   // saved! There used to be a save_bcp() that only happened in

    65   // the ASSERT path (no restore_bcp). Which caused bizarre failures

    66   // when jvm built with ASSERTs.

    67 #ifdef ASSERT

    68   { Label L;

    69     cmpptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);

    70     jcc(Assembler::equal, L);

    71     stop("InterpreterMacroAssembler::call_VM_leaf_base: last_sp != NULL");

    72     bind(L);

    73   }

    74 #endif

    75   // super call

    76   MacroAssembler::call_VM_leaf_base(entry_point, number_of_arguments);

    77   // interpreter specific

    78 

    79   // Used to ASSERT that rsi/rdi were equal to frame's bcp/locals

    80   // but since they may not have been saved (and we don't want to

    81   // save them here (see note above) the assert is invalid.

    82 }

    83 

    84 

    85 void InterpreterMacroAssembler::call_VM_base(

    86   Register oop_result,

    87   Register java_thread,

    88   Register last_java_sp,

    89   address  entry_point,

    90   int      number_of_arguments,

    91   bool     check_exceptions

    92 ) {

    93 #ifdef ASSERT

    94   { Label L;

    95     cmpptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);

    96     jcc(Assembler::equal, L);

    97     stop("InterpreterMacroAssembler::call_VM_base: last_sp != NULL");

    98     bind(L);

    99   }

   100 #endif /* ASSERT */

   101   // interpreter specific

   102   //

   103   // Note: Could avoid restoring locals ptr (callee saved) - however doesn't

   104   //       really make a difference for these runtime calls, since they are

   105   //       slow anyway. Btw., bcp must be saved/restored since it may change

   106   //       due to GC.

   107   assert(java_thread == noreg , "not expecting a precomputed java thread");

   108   save_bcp();

   109   // super call

   110   MacroAssembler::call_VM_base(oop_result, java_thread, last_java_sp, entry_point, number_of_arguments, check_exceptions);

   111   // interpreter specific

   112   restore_bcp();

   113   restore_locals();

   114 }

   115 

   116 

   117 void InterpreterMacroAssembler::check_and_handle_popframe(Register java_thread) {

   118   if (JvmtiExport::can_pop_frame()) {

   119     Label L;

   120     // Initiate popframe handling only if it is not already being processed.  If the flag

   121     // has the popframe_processing bit set, it means that this code is called *during* popframe

   122     // handling - we don't want to reenter.

   123     Register pop_cond = java_thread;  // Not clear if any other register is available...

   124     movl(pop_cond, Address(java_thread, JavaThread::popframe_condition_offset()));

   125     testl(pop_cond, JavaThread::popframe_pending_bit);

   126     jcc(Assembler::zero, L);

   127     testl(pop_cond, JavaThread::popframe_processing_bit);

   128     jcc(Assembler::notZero, L);

   129     // Call Interpreter::remove_activation_preserving_args_entry() to get the

   130     // address of the same-named entrypoint in the generated interpreter code.

   131     call_VM_leaf(CAST_FROM_FN_PTR(address, Interpreter::remove_activation_preserving_args_entry));

   132     jmp(rax);

   133     bind(L);

   134     get_thread(java_thread);

   135   }

   136 }

   137 

   138 

   139 void InterpreterMacroAssembler::load_earlyret_value(TosState state) {

   140   get_thread(rcx);

   141   movl(rcx, Address(rcx, JavaThread::jvmti_thread_state_offset()));

   142   const Address tos_addr (rcx, JvmtiThreadState::earlyret_tos_offset());

   143   const Address oop_addr (rcx, JvmtiThreadState::earlyret_oop_offset());

   144   const Address val_addr (rcx, JvmtiThreadState::earlyret_value_offset());

   145   const Address val_addr1(rcx, JvmtiThreadState::earlyret_value_offset()

   146                              + in_ByteSize(wordSize));

   147   switch (state) {

   148     case atos: movptr(rax, oop_addr);

   149                movptr(oop_addr, NULL_WORD);

   150                verify_oop(rax, state);                break;

   151     case ltos:

   152                movl(rdx, val_addr1);               // fall through

   153     case btos:                                     // fall through

   154     case ctos:                                     // fall through

   155     case stos:                                     // fall through

   156     case itos: movl(rax, val_addr);                   break;

   157     case ftos: fld_s(val_addr);                       break;

   158     case dtos: fld_d(val_addr);                       break;

   159     case vtos: /* nothing to do */                    break;

   160     default  : ShouldNotReachHere();

   161   }

   162   // Clean up tos value in the thread object

   163   movl(tos_addr,  (int32_t) ilgl);

   164   movptr(val_addr,  NULL_WORD);

   165   NOT_LP64(movptr(val_addr1, NULL_WORD));

   166 }

   167 

   168 

   169 void InterpreterMacroAssembler::check_and_handle_earlyret(Register java_thread) {

   170   if (JvmtiExport::can_force_early_return()) {

   171     Label L;

   172     Register tmp = java_thread;

   173     movptr(tmp, Address(tmp, JavaThread::jvmti_thread_state_offset()));

   174     testptr(tmp, tmp);

   175     jcc(Assembler::zero, L); // if (thread->jvmti_thread_state() == NULL) exit;

   176 

   177     // Initiate earlyret handling only if it is not already being processed.

   178     // If the flag has the earlyret_processing bit set, it means that this code

   179     // is called *during* earlyret handling - we don't want to reenter.

   180     movl(tmp, Address(tmp, JvmtiThreadState::earlyret_state_offset()));

   181     cmpl(tmp, JvmtiThreadState::earlyret_pending);

   182     jcc(Assembler::notEqual, L);

   183 

   184     // Call Interpreter::remove_activation_early_entry() to get the address of the

   185     // same-named entrypoint in the generated interpreter code.

   186     get_thread(java_thread);

   187     movptr(tmp, Address(java_thread, JavaThread::jvmti_thread_state_offset()));

   188     pushl(Address(tmp, JvmtiThreadState::earlyret_tos_offset()));

   189     call_VM_leaf(CAST_FROM_FN_PTR(address, Interpreter::remove_activation_early_entry), 1);

   190     jmp(rax);

   191     bind(L);

   192     get_thread(java_thread);

   193   }

   194 }

   195 

   196 

   197 void InterpreterMacroAssembler::get_unsigned_2_byte_index_at_bcp(Register reg, int bcp_offset) {

   198   assert(bcp_offset >= 0, "bcp is still pointing to start of bytecode");

   199   load_unsigned_short(reg, Address(rsi, bcp_offset));

   200   bswapl(reg);

   201   shrl(reg, 16);

   202 }

   203 

   204 

   205 void InterpreterMacroAssembler::get_cache_index_at_bcp(Register reg, int bcp_offset, size_t index_size) {

   206   assert(bcp_offset > 0, "bcp is still pointing to start of bytecode");

   207   if (index_size == sizeof(u2)) {

   208     load_unsigned_short(reg, Address(rsi, bcp_offset));

   209   } else if (index_size == sizeof(u4)) {

   210     movl(reg, Address(rsi, bcp_offset));

   211     // Check if the secondary index definition is still ~x, otherwise

   212     // we have to change the following assembler code to calculate the

   213     // plain index.

   214     assert(ConstantPool::decode_invokedynamic_index(~123) == 123, "else change next line");

   215     notl(reg);  // convert to plain index

   216   } else if (index_size == sizeof(u1)) {

   217     load_unsigned_byte(reg, Address(rsi, bcp_offset));

   218   } else {

   219     ShouldNotReachHere();

   220   }

   221 }

   222 

   223 

   224 void InterpreterMacroAssembler::get_cache_and_index_at_bcp(Register cache, Register index,

   225                                                            int bcp_offset, size_t index_size) {

   226   assert_different_registers(cache, index);

   227   get_cache_index_at_bcp(index, bcp_offset, index_size);

   228   movptr(cache, Address(rbp, frame::interpreter_frame_cache_offset * wordSize));

   229   assert(sizeof(ConstantPoolCacheEntry) == 4*wordSize, "adjust code below");

   230   assert(exact_log2(in_words(ConstantPoolCacheEntry::size())) == 2, "else change next line");

   231   shlptr(index, 2); // convert from field index to ConstantPoolCacheEntry index

   232 }

   233 

   234 

   235 void InterpreterMacroAssembler::get_cache_and_index_and_bytecode_at_bcp(Register cache,

   236                                                                         Register index,

   237                                                                         Register bytecode,

   238                                                                         int byte_no,

   239                                                                         int bcp_offset,

   240                                                                         size_t index_size) {

   241   get_cache_and_index_at_bcp(cache, index, bcp_offset, index_size);

   242   movptr(bytecode, Address(cache, index, Address::times_ptr, ConstantPoolCache::base_offset() + ConstantPoolCacheEntry::indices_offset()));

   243   const int shift_count = (1 + byte_no) * BitsPerByte;

   244   assert((byte_no == TemplateTable::f1_byte && shift_count == ConstantPoolCacheEntry::bytecode_1_shift) ||

   245          (byte_no == TemplateTable::f2_byte && shift_count == ConstantPoolCacheEntry::bytecode_2_shift),

   246          "correct shift count");

   247   shrptr(bytecode, shift_count);

   248   assert(ConstantPoolCacheEntry::bytecode_1_mask == ConstantPoolCacheEntry::bytecode_2_mask, "common mask");

   249   andptr(bytecode, ConstantPoolCacheEntry::bytecode_1_mask);

   250 }

   251 

   252 

   253 void InterpreterMacroAssembler::get_cache_entry_pointer_at_bcp(Register cache, Register tmp,

   254                                                                int bcp_offset, size_t index_size) {

   255   assert(cache != tmp, "must use different register");

   256   get_cache_index_at_bcp(tmp, bcp_offset, index_size);

   257   assert(sizeof(ConstantPoolCacheEntry) == 4*wordSize, "adjust code below");

   258                                // convert from field index to ConstantPoolCacheEntry index

   259                                // and from word offset to byte offset

   260   assert(exact_log2(in_bytes(ConstantPoolCacheEntry::size_in_bytes())) == 2 + LogBytesPerWord, "else change next line");

   261   shll(tmp, 2 + LogBytesPerWord);

   262   movptr(cache, Address(rbp, frame::interpreter_frame_cache_offset * wordSize));

   263                                // skip past the header

   264   addptr(cache, in_bytes(ConstantPoolCache::base_offset()));

   265   addptr(cache, tmp);            // construct pointer to cache entry

   266 }

   267 

   268 // Load object from cpool->resolved_references(index)

   269 void InterpreterMacroAssembler::load_resolved_reference_at_index(

   270                                            Register result, Register index) {

   271   assert_different_registers(result, index);

   272   // convert from field index to resolved_references() index and from

   273   // word index to byte offset. Since this is a java object, it can be compressed

   274   Register tmp = index;  // reuse

   275   shll(tmp, LogBytesPerHeapOop);

   276 

   277   get_constant_pool(result);

   278   // load pointer for resolved_references[] objArray

   279   movptr(result, Address(result, ConstantPool::resolved_references_offset_in_bytes()));

   280   // JNIHandles::resolve(obj);

   281   movptr(result, Address(result, 0));

   282   // Add in the index

   283   addptr(result, tmp);

   284   load_heap_oop(result, Address(result, arrayOopDesc::base_offset_in_bytes(T_OBJECT)));

   285 }

   286 

   287   // Generate a subtype check: branch to ok_is_subtype if sub_klass is

   288   // a subtype of super_klass.  EAX holds the super_klass.  Blows ECX.

   289   // Resets EDI to locals.  Register sub_klass cannot be any of the above.

   290 void InterpreterMacroAssembler::gen_subtype_check( Register Rsub_klass, Label &ok_is_subtype ) {

   291   assert( Rsub_klass != rax, "rax, holds superklass" );

   292   assert( Rsub_klass != rcx, "used as a temp" );

   293   assert( Rsub_klass != rdi, "used as a temp, restored from locals" );

   294 

   295   // Profile the not-null value's klass.

   296   profile_typecheck(rcx, Rsub_klass, rdi); // blows rcx, reloads rdi

   297 

   298   // Do the check.

   299   check_klass_subtype(Rsub_klass, rax, rcx, ok_is_subtype); // blows rcx

   300 

   301   // Profile the failure of the check.

   302   profile_typecheck_failed(rcx); // blows rcx

   303 }

   304 

   305 void InterpreterMacroAssembler::f2ieee() {

   306   if (IEEEPrecision) {

   307     fstp_s(Address(rsp, 0));

   308     fld_s(Address(rsp, 0));

   309   }

   310 }

   311 

   312 

   313 void InterpreterMacroAssembler::d2ieee() {

   314   if (IEEEPrecision) {

   315     fstp_d(Address(rsp, 0));

   316     fld_d(Address(rsp, 0));

   317   }

   318 }

   319 

   320 // Java Expression Stack

   321 

   322 void InterpreterMacroAssembler::pop_ptr(Register r) {

   323   pop(r);

   324 }

   325 

   326 void InterpreterMacroAssembler::pop_i(Register r) {

   327   pop(r);

   328 }

   329 

   330 void InterpreterMacroAssembler::pop_l(Register lo, Register hi) {

   331   pop(lo);

   332   pop(hi);

   333 }

   334 

   335 void InterpreterMacroAssembler::pop_f() {

   336   fld_s(Address(rsp, 0));

   337   addptr(rsp, 1 * wordSize);

   338 }

   339 

   340 void InterpreterMacroAssembler::pop_d() {

   341   fld_d(Address(rsp, 0));

   342   addptr(rsp, 2 * wordSize);

   343 }

   344 

   345 

   346 void InterpreterMacroAssembler::pop(TosState state) {

   347   switch (state) {

   348     case atos: pop_ptr(rax);                                 break;

   349     case btos:                                               // fall through

   350     case ctos:                                               // fall through

   351     case stos:                                               // fall through

   352     case itos: pop_i(rax);                                   break;

   353     case ltos: pop_l(rax, rdx);                              break;

   354     case ftos: pop_f();                                      break;

   355     case dtos: pop_d();                                      break;

   356     case vtos: /* nothing to do */                           break;

   357     default  : ShouldNotReachHere();

   358   }

   359   verify_oop(rax, state);

   360 }

   361 

   362 void InterpreterMacroAssembler::push_ptr(Register r) {

   363   push(r);

   364 }

   365 

   366 void InterpreterMacroAssembler::push_i(Register r) {

   367   push(r);

   368 }

   369 

   370 void InterpreterMacroAssembler::push_l(Register lo, Register hi) {

   371   push(hi);

   372   push(lo);

   373 }

   374 

   375 void InterpreterMacroAssembler::push_f() {

   376   // Do not schedule for no AGI! Never write beyond rsp!

   377   subptr(rsp, 1 * wordSize);

   378   fstp_s(Address(rsp, 0));

   379 }

   380 

   381 void InterpreterMacroAssembler::push_d(Register r) {

   382   // Do not schedule for no AGI! Never write beyond rsp!

   383   subptr(rsp, 2 * wordSize);

   384   fstp_d(Address(rsp, 0));

   385 }

   386 

   387 

   388 void InterpreterMacroAssembler::push(TosState state) {

   389   verify_oop(rax, state);

   390   switch (state) {

   391     case atos: push_ptr(rax); break;

   392     case btos:                                               // fall through

   393     case ctos:                                               // fall through

   394     case stos:                                               // fall through

   395     case itos: push_i(rax);                                    break;

   396     case ltos: push_l(rax, rdx);                               break;

   397     case ftos: push_f();                                       break;

   398     case dtos: push_d(rax);                                    break;

   399     case vtos: /* nothing to do */                             break;

   400     default  : ShouldNotReachHere();

   401   }

   402 }

   403 

   404 

   405 // Helpers for swap and dup

   406 void InterpreterMacroAssembler::load_ptr(int n, Register val) {

   407   movptr(val, Address(rsp, Interpreter::expr_offset_in_bytes(n)));

   408 }

   409 

   410 void InterpreterMacroAssembler::store_ptr(int n, Register val) {

   411   movptr(Address(rsp, Interpreter::expr_offset_in_bytes(n)), val);

   412 }

   413 

   414 void InterpreterMacroAssembler::prepare_to_jump_from_interpreted() {

   415   // set sender sp

   416   lea(rsi, Address(rsp, wordSize));

   417   // record last_sp

   418   movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), rsi);

   419 }

   420 

   421 

   422 // Jump to from_interpreted entry of a call unless single stepping is possible

   423 // in this thread in which case we must call the i2i entry

   424 void InterpreterMacroAssembler::jump_from_interpreted(Register method, Register temp) {

   425   prepare_to_jump_from_interpreted();

   426 

   427   if (JvmtiExport::can_post_interpreter_events()) {

   428     Label run_compiled_code;

   429     // JVMTI events, such as single-stepping, are implemented partly by avoiding running

   430     // compiled code in threads for which the event is enabled.  Check here for

   431     // interp_only_mode if these events CAN be enabled.

   432     get_thread(temp);

   433     // interp_only is an int, on little endian it is sufficient to test the byte only

   434     // Is a cmpl faster?

   435     cmpb(Address(temp, JavaThread::interp_only_mode_offset()), 0);

   436     jccb(Assembler::zero, run_compiled_code);

   437     jmp(Address(method, Method::interpreter_entry_offset()));

   438     bind(run_compiled_code);

   439   }

   440 

   441   jmp(Address(method, Method::from_interpreted_offset()));

   442 

   443 }

   444 

   445 

   446 // The following two routines provide a hook so that an implementation

   447 // can schedule the dispatch in two parts.  Intel does not do this.

   448 void InterpreterMacroAssembler::dispatch_prolog(TosState state, int step) {

   449   // Nothing Intel-specific to be done here.

   450 }

   451 

   452 void InterpreterMacroAssembler::dispatch_epilog(TosState state, int step) {

   453   dispatch_next(state, step);

   454 }

   455 

   456 void InterpreterMacroAssembler::dispatch_base(TosState state, address* table,

   457                                               bool verifyoop) {

   458   verify_FPU(1, state);

   459   if (VerifyActivationFrameSize) {

   460     Label L;

   461     mov(rcx, rbp);

   462     subptr(rcx, rsp);

   463     int min_frame_size = (frame::link_offset - frame::interpreter_frame_initial_sp_offset) * wordSize;

   464     cmpptr(rcx, min_frame_size);

   465     jcc(Assembler::greaterEqual, L);

   466     stop("broken stack frame");

   467     bind(L);

   468   }

   469   if (verifyoop) verify_oop(rax, state);

   470   Address index(noreg, rbx, Address::times_ptr);

   471   ExternalAddress tbl((address)table);

   472   ArrayAddress dispatch(tbl, index);

   473   jump(dispatch);

   474 }

   475 

   476 

   477 void InterpreterMacroAssembler::dispatch_only(TosState state) {

   478   dispatch_base(state, Interpreter::dispatch_table(state));

   479 }

   480 

   481 

   482 void InterpreterMacroAssembler::dispatch_only_normal(TosState state) {

   483   dispatch_base(state, Interpreter::normal_table(state));

   484 }

   485 

   486 void InterpreterMacroAssembler::dispatch_only_noverify(TosState state) {

   487   dispatch_base(state, Interpreter::normal_table(state), false);

   488 }

   489 

   490 

   491 void InterpreterMacroAssembler::dispatch_next(TosState state, int step) {

   492   // load next bytecode (load before advancing rsi to prevent AGI)

   493   load_unsigned_byte(rbx, Address(rsi, step));

   494   // advance rsi

   495   increment(rsi, step);

   496   dispatch_base(state, Interpreter::dispatch_table(state));

   497 }

   498 

   499 

   500 void InterpreterMacroAssembler::dispatch_via(TosState state, address* table) {

   501   // load current bytecode

   502   load_unsigned_byte(rbx, Address(rsi, 0));

   503   dispatch_base(state, table);

   504 }

   505 

   506 // remove activation

   507 //

   508 // Unlock the receiver if this is a synchronized method.

   509 // Unlock any Java monitors from syncronized blocks.

   510 // Remove the activation from the stack.

   511 //

   512 // If there are locked Java monitors

   513 //    If throw_monitor_exception

   514 //       throws IllegalMonitorStateException

   515 //    Else if install_monitor_exception

   516 //       installs IllegalMonitorStateException

   517 //    Else

   518 //       no error processing

   519 void InterpreterMacroAssembler::remove_activation(TosState state, Register ret_addr,

   520                                                   bool throw_monitor_exception,

   521                                                   bool install_monitor_exception,

   522                                                   bool notify_jvmdi) {

   523   // Note: Registers rax, rdx and FPU ST(0) may be in use for the result

   524   // check if synchronized method

   525   Label unlocked, unlock, no_unlock;

   526 

   527   get_thread(rcx);

   528   const Address do_not_unlock_if_synchronized(rcx,

   529     in_bytes(JavaThread::do_not_unlock_if_synchronized_offset()));

   530 

   531   movbool(rbx, do_not_unlock_if_synchronized);

   532   mov(rdi,rbx);

   533   movbool(do_not_unlock_if_synchronized, false); // reset the flag

   534 

   535   movptr(rbx, Address(rbp, frame::interpreter_frame_method_offset * wordSize)); // get method access flags

   536   movl(rcx, Address(rbx, Method::access_flags_offset()));

   537 

   538   testl(rcx, JVM_ACC_SYNCHRONIZED);

   539   jcc(Assembler::zero, unlocked);

   540 

   541   // Don't unlock anything if the _do_not_unlock_if_synchronized flag

   542   // is set.

   543   mov(rcx,rdi);

   544   testbool(rcx);

   545   jcc(Assembler::notZero, no_unlock);

   546 

   547   // unlock monitor

   548   push(state);                                   // save result

   549 

   550   // BasicObjectLock will be first in list, since this is a synchronized method. However, need

   551   // to check that the object has not been unlocked by an explicit monitorexit bytecode.

   552   const Address monitor(rbp, frame::interpreter_frame_initial_sp_offset * wordSize - (int)sizeof(BasicObjectLock));

   553   lea   (rdx, monitor);                          // address of first monitor

   554 

   555   movptr (rax, Address(rdx, BasicObjectLock::obj_offset_in_bytes()));

   556   testptr(rax, rax);

   557   jcc    (Assembler::notZero, unlock);

   558 

   559   pop(state);

   560   if (throw_monitor_exception) {

   561     empty_FPU_stack();  // remove possible return value from FPU-stack, otherwise stack could overflow

   562 

   563     // Entry already unlocked, need to throw exception

   564     call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::throw_illegal_monitor_state_exception));

   565     should_not_reach_here();

   566   } else {

   567     // Monitor already unlocked during a stack unroll.

   568     // If requested, install an illegal_monitor_state_exception.

   569     // Continue with stack unrolling.

   570     if (install_monitor_exception) {

   571       empty_FPU_stack();  // remove possible return value from FPU-stack, otherwise stack could overflow

   572       call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::new_illegal_monitor_state_exception));

   573     }

   574     jmp(unlocked);

   575   }

   576 

   577   bind(unlock);

   578   unlock_object(rdx);

   579   pop(state);

   580 

   581   // Check that for block-structured locking (i.e., that all locked objects has been unlocked)

   582   bind(unlocked);

   583 

   584   // rax, rdx: Might contain return value

   585 

   586   // Check that all monitors are unlocked

   587   {

   588     Label loop, exception, entry, restart;

   589     const int entry_size               = frame::interpreter_frame_monitor_size()           * wordSize;

   590     const Address monitor_block_top(rbp, frame::interpreter_frame_monitor_block_top_offset * wordSize);

   591     const Address monitor_block_bot(rbp, frame::interpreter_frame_initial_sp_offset        * wordSize);

   592 

   593     bind(restart);

   594     movptr(rcx, monitor_block_top);           // points to current entry, starting with top-most entry

   595     lea(rbx, monitor_block_bot);              // points to word before bottom of monitor block

   596     jmp(entry);

   597 

   598     // Entry already locked, need to throw exception

   599     bind(exception);

   600 

   601     if (throw_monitor_exception) {

   602       empty_FPU_stack();  // remove possible return value from FPU-stack, otherwise stack could overflow

   603 

   604       // Throw exception

   605       call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::throw_illegal_monitor_state_exception));

   606       should_not_reach_here();

   607     } else {

   608       // Stack unrolling. Unlock object and install illegal_monitor_exception

   609       // Unlock does not block, so don't have to worry about the frame

   610 

   611       push(state);

   612       mov(rdx, rcx);

   613       unlock_object(rdx);

   614       pop(state);

   615 

   616       if (install_monitor_exception) {

   617         empty_FPU_stack();  // remove possible return value from FPU-stack, otherwise stack could overflow

   618         call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::new_illegal_monitor_state_exception));

   619       }

   620 

   621       jmp(restart);

   622     }

   623 

   624     bind(loop);

   625     cmpptr(Address(rcx, BasicObjectLock::obj_offset_in_bytes()), (int32_t)NULL_WORD);  // check if current entry is used

   626     jcc(Assembler::notEqual, exception);

   627 

   628     addptr(rcx, entry_size);                     // otherwise advance to next entry

   629     bind(entry);

   630     cmpptr(rcx, rbx);                            // check if bottom reached

   631     jcc(Assembler::notEqual, loop);              // if not at bottom then check this entry

   632   }

   633 

   634   bind(no_unlock);

   635 

   636   // jvmti support

   637   if (notify_jvmdi) {

   638     notify_method_exit(state, NotifyJVMTI);     // preserve TOSCA

   639   } else {

   640     notify_method_exit(state, SkipNotifyJVMTI); // preserve TOSCA

   641   }

   642 

   643   // remove activation

   644   movptr(rbx, Address(rbp, frame::interpreter_frame_sender_sp_offset * wordSize)); // get sender sp

   645   leave();                                     // remove frame anchor

   646   pop(ret_addr);                               // get return address

   647   mov(rsp, rbx);                               // set sp to sender sp

   648   if (UseSSE) {

   649     // float and double are returned in xmm register in SSE-mode

   650     if (state == ftos && UseSSE >= 1) {

   651       subptr(rsp, wordSize);

   652       fstp_s(Address(rsp, 0));

   653       movflt(xmm0, Address(rsp, 0));

   654       addptr(rsp, wordSize);

   655     } else if (state == dtos && UseSSE >= 2) {

   656       subptr(rsp, 2*wordSize);

   657       fstp_d(Address(rsp, 0));

   658       movdbl(xmm0, Address(rsp, 0));

   659       addptr(rsp, 2*wordSize);

   660     }

   661   }

   662 }

   663 

   664 #endif /* !CC_INTERP */

   665 

   666 void InterpreterMacroAssembler::get_method_counters(Register method,

   667                                                     Register mcs, Label& skip) {

   668   Label has_counters;

   669   movptr(mcs, Address(method, Method::method_counters_offset()));

   670   testptr(mcs, mcs);

   671   jcc(Assembler::notZero, has_counters);

   672   call_VM(noreg, CAST_FROM_FN_PTR(address,

   673           InterpreterRuntime::build_method_counters), method);

   674   movptr(mcs, Address(method,Method::method_counters_offset()));

   675   testptr(mcs, mcs);

   676   jcc(Assembler::zero, skip); // No MethodCounters allocated, OutOfMemory

   677   bind(has_counters);

   678 }

   679 

   680 

   681 // Lock object

   682 //

   683 // Argument: rdx : Points to BasicObjectLock to be used for locking. Must

   684 // be initialized with object to lock

   685 void InterpreterMacroAssembler::lock_object(Register lock_reg) {

   686   assert(lock_reg == rdx, "The argument is only for looks. It must be rdx");

   687 

   688   if (UseHeavyMonitors) {

   689     call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorenter), lock_reg);

   690   } else {

   691 

   692     Label done;

   693 

   694     const Register swap_reg = rax;  // Must use rax, for cmpxchg instruction

   695     const Register obj_reg  = rcx;  // Will contain the oop

   696 

   697     const int obj_offset = BasicObjectLock::obj_offset_in_bytes();

   698     const int lock_offset = BasicObjectLock::lock_offset_in_bytes ();

   699     const int mark_offset = lock_offset + BasicLock::displaced_header_offset_in_bytes();

   700 

   701     Label slow_case;

   702 

   703     // Load object pointer into obj_reg %rcx

   704     movptr(obj_reg, Address(lock_reg, obj_offset));

   705 

   706     if (UseBiasedLocking) {

   707       // Note: we use noreg for the temporary register since it's hard

   708       // to come up with a free register on all incoming code paths

   709       biased_locking_enter(lock_reg, obj_reg, swap_reg, noreg, false, done, &slow_case);

   710     }

   711 

   712     // Load immediate 1 into swap_reg %rax,

   713     movptr(swap_reg, (int32_t)1);

   714 

   715     // Load (object->mark() | 1) into swap_reg %rax,

   716     orptr(swap_reg, Address(obj_reg, 0));

   717 

   718     // Save (object->mark() | 1) into BasicLock's displaced header

   719     movptr(Address(lock_reg, mark_offset), swap_reg);

   720 

   721     assert(lock_offset == 0, "displached header must be first word in BasicObjectLock");

   722     if (os::is_MP()) {

   723       lock();

   724     }

   725     cmpxchgptr(lock_reg, Address(obj_reg, 0));

   726     if (PrintBiasedLockingStatistics) {

   727       cond_inc32(Assembler::zero,

   728                  ExternalAddress((address) BiasedLocking::fast_path_entry_count_addr()));

   729     }

   730     jcc(Assembler::zero, done);

   731 

   732     // Test if the oopMark is an obvious stack pointer, i.e.,

   733     //  1) (mark & 3) == 0, and

   734     //  2) rsp <= mark < mark + os::pagesize()

   735     //

   736     // These 3 tests can be done by evaluating the following

   737     // expression: ((mark - rsp) & (3 - os::vm_page_size())),

   738     // assuming both stack pointer and pagesize have their

   739     // least significant 2 bits clear.

   740     // NOTE: the oopMark is in swap_reg %rax, as the result of cmpxchg

   741     subptr(swap_reg, rsp);

   742     andptr(swap_reg, 3 - os::vm_page_size());

   743 

   744     // Save the test result, for recursive case, the result is zero

   745     movptr(Address(lock_reg, mark_offset), swap_reg);

   746 

   747     if (PrintBiasedLockingStatistics) {

   748       cond_inc32(Assembler::zero,

   749                  ExternalAddress((address) BiasedLocking::fast_path_entry_count_addr()));

   750     }

   751     jcc(Assembler::zero, done);

   752 

   753     bind(slow_case);

   754 

   755     // Call the runtime routine for slow case

   756     call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorenter), lock_reg);

   757 

   758     bind(done);

   759   }

   760 }

   761 

   762 

   763 // Unlocks an object. Used in monitorexit bytecode and remove_activation.

   764 //

   765 // Argument: rdx : Points to BasicObjectLock structure for lock

   766 // Throw an IllegalMonitorException if object is not locked by current thread

   767 //

   768 // Uses: rax, rbx, rcx, rdx

   769 void InterpreterMacroAssembler::unlock_object(Register lock_reg) {

   770   assert(lock_reg == rdx, "The argument is only for looks. It must be rdx");

   771 

   772   if (UseHeavyMonitors) {

   773     call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorexit), lock_reg);

   774   } else {

   775     Label done;

   776 

   777     const Register swap_reg   = rax;  // Must use rax, for cmpxchg instruction

   778     const Register header_reg = rbx;  // Will contain the old oopMark

   779     const Register obj_reg    = rcx;  // Will contain the oop

   780 

   781     save_bcp(); // Save in case of exception

   782 

   783     // Convert from BasicObjectLock structure to object and BasicLock structure

   784     // Store the BasicLock address into %rax,

   785     lea(swap_reg, Address(lock_reg, BasicObjectLock::lock_offset_in_bytes()));

   786 

   787     // Load oop into obj_reg(%rcx)

   788     movptr(obj_reg, Address(lock_reg, BasicObjectLock::obj_offset_in_bytes ()));

   789 

   790     // Free entry

   791     movptr(Address(lock_reg, BasicObjectLock::obj_offset_in_bytes()), NULL_WORD);

   792 

   793     if (UseBiasedLocking) {

   794       biased_locking_exit(obj_reg, header_reg, done);

   795     }

   796 

   797     // Load the old header from BasicLock structure

   798     movptr(header_reg, Address(swap_reg, BasicLock::displaced_header_offset_in_bytes()));

   799 

   800     // Test for recursion

   801     testptr(header_reg, header_reg);

   802 

   803     // zero for recursive case

   804     jcc(Assembler::zero, done);

   805 

   806     // Atomic swap back the old header

   807     if (os::is_MP()) lock();

   808     cmpxchgptr(header_reg, Address(obj_reg, 0));

   809 

   810     // zero for recursive case

   811     jcc(Assembler::zero, done);

   812 

   813     // Call the runtime routine for slow case.

   814     movptr(Address(lock_reg, BasicObjectLock::obj_offset_in_bytes()), obj_reg); // restore obj

   815     call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::monitorexit), lock_reg);

   816 

   817     bind(done);

   818 

   819     restore_bcp();

   820   }

   821 }

   822 

   823 

   824 #ifndef CC_INTERP

   825 

   826 // Test ImethodDataPtr.  If it is null, continue at the specified label

   827 void InterpreterMacroAssembler::test_method_data_pointer(Register mdp, Label& zero_continue) {

   828   assert(ProfileInterpreter, "must be profiling interpreter");

   829   movptr(mdp, Address(rbp, frame::interpreter_frame_mdp_offset * wordSize));

   830   testptr(mdp, mdp);

   831   jcc(Assembler::zero, zero_continue);

   832 }

   833 

   834 

   835 // Set the method data pointer for the current bcp.

   836 void InterpreterMacroAssembler::set_method_data_pointer_for_bcp() {

   837   assert(ProfileInterpreter, "must be profiling interpreter");

   838   Label set_mdp;

   839   push(rax);

   840   push(rbx);

   841 

   842   get_method(rbx);

   843   // Test MDO to avoid the call if it is NULL.

   844   movptr(rax, Address(rbx, in_bytes(Method::method_data_offset())));

   845   testptr(rax, rax);

   846   jcc(Assembler::zero, set_mdp);

   847   // rbx,: method

   848   // rsi: bcp

   849   call_VM_leaf(CAST_FROM_FN_PTR(address, InterpreterRuntime::bcp_to_di), rbx, rsi);

   850   // rax,: mdi

   851   // mdo is guaranteed to be non-zero here, we checked for it before the call.

   852   movptr(rbx, Address(rbx, in_bytes(Method::method_data_offset())));

   853   addptr(rbx, in_bytes(MethodData::data_offset()));

   854   addptr(rax, rbx);

   855   bind(set_mdp);

   856   movptr(Address(rbp, frame::interpreter_frame_mdp_offset * wordSize), rax);

   857   pop(rbx);

   858   pop(rax);

   859 }

   860 

   861 void InterpreterMacroAssembler::verify_method_data_pointer() {

   862   assert(ProfileInterpreter, "must be profiling interpreter");

   863 #ifdef ASSERT

   864   Label verify_continue;

   865   push(rax);

   866   push(rbx);

   867   push(rcx);

   868   push(rdx);

   869   test_method_data_pointer(rcx, verify_continue); // If mdp is zero, continue

   870   get_method(rbx);

   871 

   872   // If the mdp is valid, it will point to a DataLayout header which is

   873   // consistent with the bcp.  The converse is highly probable also.

   874   load_unsigned_short(rdx, Address(rcx, in_bytes(DataLayout::bci_offset())));

   875   addptr(rdx, Address(rbx, Method::const_offset()));

   876   lea(rdx, Address(rdx, ConstMethod::codes_offset()));

   877   cmpptr(rdx, rsi);

   878   jcc(Assembler::equal, verify_continue);

   879   // rbx,: method

   880   // rsi: bcp

   881   // rcx: mdp

   882   call_VM_leaf(CAST_FROM_FN_PTR(address, InterpreterRuntime::verify_mdp), rbx, rsi, rcx);

   883   bind(verify_continue);

   884   pop(rdx);

   885   pop(rcx);

   886   pop(rbx);

   887   pop(rax);

   888 #endif // ASSERT

   889 }

   890 

   891 

   892 void InterpreterMacroAssembler::set_mdp_data_at(Register mdp_in, int constant, Register value) {

   893   // %%% this seems to be used to store counter data which is surely 32bits

   894   // however 64bit side stores 64 bits which seems wrong

   895   assert(ProfileInterpreter, "must be profiling interpreter");

   896   Address data(mdp_in, constant);

   897   movptr(data, value);

   898 }

   899 

   900 

   901 void InterpreterMacroAssembler::increment_mdp_data_at(Register mdp_in,

   902                                                       int constant,

   903                                                       bool decrement) {

   904   // Counter address

   905   Address data(mdp_in, constant);

   906 

   907   increment_mdp_data_at(data, decrement);

   908 }

   909 

   910 

   911 void InterpreterMacroAssembler::increment_mdp_data_at(Address data,

   912                                                       bool decrement) {

   913 

   914   assert( DataLayout::counter_increment==1, "flow-free idiom only works with 1" );

   915   assert(ProfileInterpreter, "must be profiling interpreter");

   916 

   917   // %%% 64bit treats this as 64 bit which seems unlikely

   918   if (decrement) {

   919     // Decrement the register.  Set condition codes.

   920     addl(data, -DataLayout::counter_increment);

   921     // If the decrement causes the counter to overflow, stay negative

   922     Label L;

   923     jcc(Assembler::negative, L);

   924     addl(data, DataLayout::counter_increment);

   925     bind(L);

   926   } else {

   927     assert(DataLayout::counter_increment == 1,

   928            "flow-free idiom only works with 1");

   929     // Increment the register.  Set carry flag.

   930     addl(data, DataLayout::counter_increment);

   931     // If the increment causes the counter to overflow, pull back by 1.

   932     sbbl(data, 0);

   933   }

   934 }

   935 

   936 

   937 void InterpreterMacroAssembler::increment_mdp_data_at(Register mdp_in,

   938                                                       Register reg,

   939                                                       int constant,

   940                                                       bool decrement) {

   941   Address data(mdp_in, reg, Address::times_1, constant);

   942 

   943   increment_mdp_data_at(data, decrement);

   944 }

   945 

   946 

   947 void InterpreterMacroAssembler::set_mdp_flag_at(Register mdp_in, int flag_byte_constant) {

   948   assert(ProfileInterpreter, "must be profiling interpreter");

   949   int header_offset = in_bytes(DataLayout::header_offset());

   950   int header_bits = DataLayout::flag_mask_to_header_mask(flag_byte_constant);

   951   // Set the flag

   952   orl(Address(mdp_in, header_offset), header_bits);

   953 }

   954 

   955 

   956 

   957 void InterpreterMacroAssembler::test_mdp_data_at(Register mdp_in,

   958                                                  int offset,

   959                                                  Register value,

   960                                                  Register test_value_out,

   961                                                  Label& not_equal_continue) {

   962   assert(ProfileInterpreter, "must be profiling interpreter");

   963   if (test_value_out == noreg) {

   964     cmpptr(value, Address(mdp_in, offset));

   965   } else {

   966     // Put the test value into a register, so caller can use it:

   967     movptr(test_value_out, Address(mdp_in, offset));

   968     cmpptr(test_value_out, value);

   969   }

   970   jcc(Assembler::notEqual, not_equal_continue);

   971 }

   972 

   973 

   974 void InterpreterMacroAssembler::update_mdp_by_offset(Register mdp_in, int offset_of_disp) {

   975   assert(ProfileInterpreter, "must be profiling interpreter");

   976   Address disp_address(mdp_in, offset_of_disp);

   977   addptr(mdp_in,disp_address);

   978   movptr(Address(rbp, frame::interpreter_frame_mdp_offset * wordSize), mdp_in);

   979 }

   980 

   981 

   982 void InterpreterMacroAssembler::update_mdp_by_offset(Register mdp_in, Register reg, int offset_of_disp) {

   983   assert(ProfileInterpreter, "must be profiling interpreter");

   984   Address disp_address(mdp_in, reg, Address::times_1, offset_of_disp);

   985   addptr(mdp_in, disp_address);

   986   movptr(Address(rbp, frame::interpreter_frame_mdp_offset * wordSize), mdp_in);

   987 }

   988 

   989 

   990 void InterpreterMacroAssembler::update_mdp_by_constant(Register mdp_in, int constant) {

   991   assert(ProfileInterpreter, "must be profiling interpreter");

   992   addptr(mdp_in, constant);

   993   movptr(Address(rbp, frame::interpreter_frame_mdp_offset * wordSize), mdp_in);

   994 }

   995 

   996 

   997 void InterpreterMacroAssembler::update_mdp_for_ret(Register return_bci) {

   998   assert(ProfileInterpreter, "must be profiling interpreter");

   999   push(return_bci);             // save/restore across call_VM

  1000   call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::update_mdp_for_ret), return_bci);

  1001   pop(return_bci);

  1002 }

  1003 

  1004 

  1005 void InterpreterMacroAssembler::profile_taken_branch(Register mdp, Register bumped_count) {

  1006   if (ProfileInterpreter) {

  1007     Label profile_continue;

  1008 

  1009     // If no method data exists, go to profile_continue.

  1010     // Otherwise, assign to mdp

  1011     test_method_data_pointer(mdp, profile_continue);

  1012 

  1013     // We are taking a branch.  Increment the taken count.

  1014     // We inline increment_mdp_data_at to return bumped_count in a register

  1015     //increment_mdp_data_at(mdp, in_bytes(JumpData::taken_offset()));

  1016     Address data(mdp, in_bytes(JumpData::taken_offset()));

  1017 

  1018     // %%% 64bit treats these cells as 64 bit but they seem to be 32 bit

  1019     movl(bumped_count,data);

  1020     assert( DataLayout::counter_increment==1, "flow-free idiom only works with 1" );

  1021     addl(bumped_count, DataLayout::counter_increment);

  1022     sbbl(bumped_count, 0);

  1023     movl(data,bumped_count);    // Store back out

  1024 

  1025     // The method data pointer needs to be updated to reflect the new target.

  1026     update_mdp_by_offset(mdp, in_bytes(JumpData::displacement_offset()));

  1027     bind (profile_continue);

  1028   }

  1029 }

  1030 

  1031 

  1032 void InterpreterMacroAssembler::profile_not_taken_branch(Register mdp) {

  1033   if (ProfileInterpreter) {

  1034     Label profile_continue;

  1035 

  1036     // If no method data exists, go to profile_continue.

  1037     test_method_data_pointer(mdp, profile_continue);

  1038 

  1039     // We are taking a branch.  Increment the not taken count.

  1040     increment_mdp_data_at(mdp, in_bytes(BranchData::not_taken_offset()));

  1041 

  1042     // The method data pointer needs to be updated to correspond to the next bytecode

  1043     update_mdp_by_constant(mdp, in_bytes(BranchData::branch_data_size()));

  1044     bind (profile_continue);

  1045   }

  1046 }

  1047 

  1048 void InterpreterMacroAssembler::profile_call(Register mdp) {

  1049   if (ProfileInterpreter) {

  1050     Label profile_continue;

  1051 

  1052     // If no method data exists, go to profile_continue.

  1053     test_method_data_pointer(mdp, profile_continue);

  1054 

  1055     // We are making a call.  Increment the count.

  1056     increment_mdp_data_at(mdp, in_bytes(CounterData::count_offset()));

  1057 

  1058     // The method data pointer needs to be updated to reflect the new target.

  1059     update_mdp_by_constant(mdp, in_bytes(CounterData::counter_data_size()));

  1060     bind (profile_continue);

  1061   }

  1062 }

  1063 

  1064 

  1065 void InterpreterMacroAssembler::profile_final_call(Register mdp) {

  1066   if (ProfileInterpreter) {

  1067     Label profile_continue;

  1068 

  1069     // If no method data exists, go to profile_continue.

  1070     test_method_data_pointer(mdp, profile_continue);

  1071 

  1072     // We are making a call.  Increment the count.

  1073     increment_mdp_data_at(mdp, in_bytes(CounterData::count_offset()));

  1074 

  1075     // The method data pointer needs to be updated to reflect the new target.

  1076     update_mdp_by_constant(mdp, in_bytes(VirtualCallData::virtual_call_data_size()));

  1077     bind (profile_continue);

  1078   }

  1079 }

  1080 

  1081 

  1082 void InterpreterMacroAssembler::profile_virtual_call(Register receiver, Register mdp,

  1083                                                      Register reg2,

  1084                                                      bool receiver_can_be_null) {

  1085   if (ProfileInterpreter) {

  1086     Label profile_continue;

  1087 

  1088     // If no method data exists, go to profile_continue.

  1089     test_method_data_pointer(mdp, profile_continue);

  1090 

  1091     Label skip_receiver_profile;

  1092     if (receiver_can_be_null) {

  1093       Label not_null;

  1094       testptr(receiver, receiver);

  1095       jccb(Assembler::notZero, not_null);

  1096       // We are making a call.  Increment the count for null receiver.

  1097       increment_mdp_data_at(mdp, in_bytes(CounterData::count_offset()));

  1098       jmp(skip_receiver_profile);

  1099       bind(not_null);

  1100     }

  1101 

  1102     // Record the receiver type.

  1103     record_klass_in_profile(receiver, mdp, reg2, true);

  1104     bind(skip_receiver_profile);

  1105 

  1106     // The method data pointer needs to be updated to reflect the new target.

  1107     update_mdp_by_constant(mdp,

  1108                            in_bytes(VirtualCallData::

  1109                                     virtual_call_data_size()));

  1110     bind(profile_continue);

  1111   }

  1112 }

  1113 

  1114 

  1115 void InterpreterMacroAssembler::record_klass_in_profile_helper(

  1116                                         Register receiver, Register mdp,

  1117                                         Register reg2, int start_row,

  1118                                         Label& done, bool is_virtual_call) {

  1119   if (TypeProfileWidth == 0) {

  1120     if (is_virtual_call) {

  1121       increment_mdp_data_at(mdp, in_bytes(CounterData::count_offset()));

  1122     }

  1123     return;

  1124   }

  1125 

  1126   int last_row = VirtualCallData::row_limit() - 1;

  1127   assert(start_row <= last_row, "must be work left to do");

  1128   // Test this row for both the receiver and for null.

  1129   // Take any of three different outcomes:

  1130   //   1. found receiver => increment count and goto done

  1131   //   2. found null => keep looking for case 1, maybe allocate this cell

  1132   //   3. found something else => keep looking for cases 1 and 2

  1133   // Case 3 is handled by a recursive call.

  1134   for (int row = start_row; row <= last_row; row++) {