1 /*
  2  * Copyright (c) 1997, 2024, 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 #ifndef SHARE_RUNTIME_STUBROUTINES_HPP
 26 #define SHARE_RUNTIME_STUBROUTINES_HPP
 27 
 28 #include "code/codeBlob.hpp"
 29 #include "memory/allocation.hpp"
 30 #include "prims/vectorSupport.hpp"
 31 #include "runtime/frame.hpp"
 32 #include "runtime/mutexLocker.hpp"
 33 #include "runtime/stubCodeGenerator.hpp"
 34 #include "runtime/threadWXSetters.inline.hpp"
 35 #include "utilities/macros.hpp"
 36 
 37 // StubRoutines provides entry points to assembly routines used by
 38 // compiled code and the run-time system. Platform-specific entry
 39 // points are defined in the platform-specific inner class. Most
 40 // routines have a single (main) entry point. However, a few routines
 41 // do provide alternative entry points.
 42 //
 43 // Stub routines whose entries are advertised via class StubRoutines
 44 // are generated in batches at well-defined stages during JVM init:
 45 // initial stubs, continuation stubs, compiler stubs, final stubs.
 46 // Each batch is embedded in a single, associated blob (an instance of
 47 // BufferBlob) i.e. the blob to entry relationship is 1-m.
 48 //
 49 // Note that this constrasts with the much smaller number of stub
 50 // routines generated via classes SharedRuntime, c1_Runtime1 and
 51 // OptoRuntime. The latter routines are also generated at well-defined
 52 // points during JVM init. However, each stub routine has its own
 53 // unique blob (various subclasses of RuntimeBlob) i.e. the blob to
 54 // entry relationship is 1-1. The difference arises because
 55 // SharedRuntime routines may need to be relocatable or advertise
 56 // properties such as a frame size via their blob.
 57 //
 58 // Staging of stub routine generation is needed in order to manage
 59 // init dependencies between 1) stubs and other stubs or 2) stubs and
 60 // other runtime components. For example, some exception throw stubs
 61 // need to be generated before compiler stubs (such as the
 62 // deoptimization stub) so that the latter can invoke the thrwo rotine
 63 // in bail-out code. Likewise, stubs that access objects (such as the
 64 // object array copy stub) need to be created after initialization of
 65 // some GC constants and generation of the GC barrier stubs they might
 66 // need to invoke.
 67 //
 68 // Class scheme:
 69 //
 70 //    platform-independent               platform-dependent
 71 //
 72 //    stubRoutines.hpp  <-- included --  stubRoutines_<arch>.hpp
 73 //           ^                                  ^
 74 //           |                                  |
 75 //       implements                         implements
 76 //           |                                  |
 77 //           |                                  |
 78 //    stubRoutines.cpp                   stubRoutines_<arch>.cpp
 79 //                                       stubGenerator_<arch>.cpp
 80 //
 81 // Note 1: The important thing is a clean decoupling between stub
 82 //         entry points (interfacing to the whole vm; i.e., 1-to-n
 83 //         relationship) and stub generators (interfacing only to
 84 //         the entry points implementation; i.e., 1-to-1 relationship).
 85 //         This significantly simplifies changes in the generator
 86 //         structure since the rest of the vm is not affected.
 87 //
 88 // Note 2: stubGenerator_<arch>.cpp contains a minimal portion of
 89 //         machine-independent code; namely the generator calls of
 90 //         the generator functions that are used platform-independently.
 91 //         However, it comes with the advantage of having a 1-file
 92 //         implementation of the generator. It should be fairly easy
 93 //         to change, should it become a problem later.
 94 //
 95 // Scheme for adding a new entry point:
 96 //
 97 // 1. determine if it's a platform-dependent or independent entry point
 98 //    a) if platform independent: make subsequent changes in the independent files
 99 //    b) if platform   dependent: make subsequent changes in the   dependent files
100 // 2. add a private instance variable holding the entry point address
101 // 3. add a public accessor function to the instance variable
102 // 4. implement the corresponding generator function in the platform-dependent
103 //    stubGenerator_<arch>.cpp file and call the function in generate_all() of that file
104 // 5. ensure the entry is generated in the right blob to satisfy initialization
105 //    dependencies between it and other stubs or runtime components.
106 
107 class UnsafeMemoryAccess : public CHeapObj<mtCode> {
108  private:
109   address _start_pc;
110   address _end_pc;
111   address _error_exit_pc;
112  public:
113   static address           _common_exit_stub_pc;
114   static UnsafeMemoryAccess* _table;
115   static int               _table_length;
116   static int               _table_max_length;
117   UnsafeMemoryAccess() : _start_pc(nullptr), _end_pc(nullptr), _error_exit_pc(nullptr) {}
118   void    set_start_pc(address pc)      { _start_pc = pc; }
119   void    set_end_pc(address pc)        { _end_pc = pc; }
120   void    set_error_exit_pc(address pc) { _error_exit_pc = pc; }
121   address start_pc()      const { return _start_pc; }
122   address end_pc()        const { return _end_pc; }
123   address error_exit_pc() const { return _error_exit_pc; }
124 
125   static void    set_common_exit_stub_pc(address pc) { _common_exit_stub_pc = pc; }
126   static address common_exit_stub_pc()               { return _common_exit_stub_pc; }
127 
128   static UnsafeMemoryAccess* add_to_table(address start_pc, address end_pc, address error_exit_pc) {
129     guarantee(_table_length < _table_max_length, "Incorrect UnsafeMemoryAccess::_table_max_length");
130     UnsafeMemoryAccess* entry = &_table[_table_length];
131     entry->set_start_pc(start_pc);
132     entry->set_end_pc(end_pc);
133     entry->set_error_exit_pc(error_exit_pc);
134 
135     _table_length++;
136     return entry;
137   }
138 
139   static bool    contains_pc(address pc);
140   static address page_error_continue_pc(address pc);
141   static void    create_table(int max_size);
142 };
143 
144 class UnsafeMemoryAccessMark : public StackObj {
145  private:
146   UnsafeMemoryAccess*  _ucm_entry;
147   StubCodeGenerator* _cgen;
148  public:
149   UnsafeMemoryAccessMark(StubCodeGenerator* cgen, bool add_entry, bool continue_at_scope_end, address error_exit_pc = nullptr);
150   ~UnsafeMemoryAccessMark();
151 };
152 
153 class StubRoutines: AllStatic {
154 
155  public:
156   // Dependencies
157   friend class StubGenerator;
158 
159 #include CPU_HEADER(stubRoutines)
160 
161   static jint    _verify_oop_count;
162   static address _verify_oop_subroutine_entry;
163 
164   static address _call_stub_return_address;                // the return PC, when returning to a call stub
165   static address _call_stub_entry;
166   static address _forward_exception_entry;
167   static address _catch_exception_entry;
168 
169   static address _atomic_xchg_entry;
170   static address _atomic_cmpxchg_entry;
171   static address _atomic_cmpxchg_long_entry;
172   static address _atomic_add_entry;
173   static address _fence_entry;
174 
175   static BufferBlob* _initial_stubs_code;                  // code buffer for initial routines
176   static BufferBlob* _continuation_stubs_code;             // code buffer for continuation stubs
177   static BufferBlob* _compiler_stubs_code;                 // code buffer for C2 intrinsics
178   static BufferBlob* _final_stubs_code;                    // code buffer for all other routines
179 
180   static address _array_sort;
181   static address _array_partition;
182   // Leaf routines which implement arraycopy and their addresses
183   // arraycopy operands aligned on element type boundary
184   static address _jbyte_arraycopy;
185   static address _jshort_arraycopy;
186   static address _jint_arraycopy;
187   static address _jlong_arraycopy;
188   static address _oop_arraycopy, _oop_arraycopy_uninit;
189   static address _jbyte_disjoint_arraycopy;
190   static address _jshort_disjoint_arraycopy;
191   static address _jint_disjoint_arraycopy;
192   static address _jlong_disjoint_arraycopy;
193   static address _oop_disjoint_arraycopy, _oop_disjoint_arraycopy_uninit;
194 
195   // arraycopy operands aligned on zero'th element boundary
196   // These are identical to the ones aligned aligned on an
197   // element type boundary, except that they assume that both
198   // source and destination are HeapWord aligned.
199   static address _arrayof_jbyte_arraycopy;
200   static address _arrayof_jshort_arraycopy;
201   static address _arrayof_jint_arraycopy;
202   static address _arrayof_jlong_arraycopy;
203   static address _arrayof_oop_arraycopy, _arrayof_oop_arraycopy_uninit;
204   static address _arrayof_jbyte_disjoint_arraycopy;
205   static address _arrayof_jshort_disjoint_arraycopy;
206   static address _arrayof_jint_disjoint_arraycopy;
207   static address _arrayof_jlong_disjoint_arraycopy;
208   static address _arrayof_oop_disjoint_arraycopy, _arrayof_oop_disjoint_arraycopy_uninit;
209 
210   // cache line writeback
211   static address _data_cache_writeback;
212   static address _data_cache_writeback_sync;
213 
214   // these are recommended but optional:
215   static address _checkcast_arraycopy, _checkcast_arraycopy_uninit;
216   static address _unsafe_arraycopy;
217   static address _generic_arraycopy;
218 
219   static address _unsafe_setmemory;
220 
221   static address _jbyte_fill;
222   static address _jshort_fill;
223   static address _jint_fill;
224   static address _arrayof_jbyte_fill;
225   static address _arrayof_jshort_fill;
226   static address _arrayof_jint_fill;
227 
228   static address _aescrypt_encryptBlock;
229   static address _aescrypt_decryptBlock;
230   static address _cipherBlockChaining_encryptAESCrypt;
231   static address _cipherBlockChaining_decryptAESCrypt;
232   static address _electronicCodeBook_encryptAESCrypt;
233   static address _electronicCodeBook_decryptAESCrypt;
234   static address _counterMode_AESCrypt;
235   static address _galoisCounterMode_AESCrypt;
236   static address _ghash_processBlocks;
237   static address _chacha20Block;
238   static address _base64_encodeBlock;
239   static address _base64_decodeBlock;
240   static address _poly1305_processBlocks;
241   static address _intpoly_montgomeryMult_P256;
242   static address _intpoly_assign;
243 
244   static address _md5_implCompress;
245   static address _md5_implCompressMB;
246   static address _sha1_implCompress;
247   static address _sha1_implCompressMB;
248   static address _sha256_implCompress;
249   static address _sha256_implCompressMB;
250   static address _sha512_implCompress;
251   static address _sha512_implCompressMB;
252   static address _sha3_implCompress;
253   static address _sha3_implCompressMB;
254 
255   static address _updateBytesCRC32;
256   static address _crc_table_adr;
257 
258   static address _string_indexof_array[4];
259 
260   static address _crc32c_table_addr;
261   static address _updateBytesCRC32C;
262   static address _updateBytesAdler32;
263 
264   static address _multiplyToLen;
265   static address _squareToLen;
266   static address _mulAdd;
267   static address _montgomeryMultiply;
268   static address _montgomerySquare;
269   static address _bigIntegerRightShiftWorker;
270   static address _bigIntegerLeftShiftWorker;
271 
272   static address _vectorizedMismatch;
273 
274   static address _dexp;
275   static address _dlog;
276   static address _dlog10;
277   static address _dpow;
278   static address _dsin;
279   static address _dcos;
280   static address _dlibm_sin_cos_huge;
281   static address _dlibm_reduce_pi04l;
282   static address _dlibm_tan_cot_huge;
283   static address _dtan;
284   static address _dtanh;
285   static address _fmod;
286 
287   static address _f2hf;
288   static address _hf2f;
289 
290   static address _method_entry_barrier;
291 
292   static address _cont_thaw;
293   static address _cont_returnBarrier;
294   static address _cont_returnBarrierExc;
295   static address _cont_preempt_stub;
296 
297   // Vector Math Routines
298   static address _vector_f_math[VectorSupport::NUM_VEC_SIZES][VectorSupport::NUM_VECTOR_OP_MATH];
299   static address _vector_d_math[VectorSupport::NUM_VEC_SIZES][VectorSupport::NUM_VECTOR_OP_MATH];
300 
301   static address _upcall_stub_exception_handler;
302   static address _upcall_stub_load_target;
303 
304   static address _lookup_secondary_supers_table_stubs[];
305   static address _lookup_secondary_supers_table_slow_path_stub;
306 
307  public:
308   // Initialization/Testing
309   static void    initialize_initial_stubs();               // must happen before universe::genesis
310   static void    initialize_continuation_stubs();          // must happen after  universe::genesis
311   static void    initialize_compiler_stubs();              // must happen after  universe::genesis
312   static void    initialize_final_stubs();                 // must happen after  universe::genesis
313 
314   static bool is_stub_code(address addr)                   { return contains(addr); }
315 
316   static bool contains(address addr) {
317     return
318       (_initial_stubs_code      != nullptr && _initial_stubs_code->blob_contains(addr))  ||
319       (_continuation_stubs_code != nullptr && _continuation_stubs_code->blob_contains(addr)) ||
320       (_compiler_stubs_code     != nullptr && _compiler_stubs_code->blob_contains(addr)) ||
321       (_final_stubs_code        != nullptr && _final_stubs_code->blob_contains(addr)) ;
322   }
323 
324   static RuntimeBlob* initial_stubs_code()      { return _initial_stubs_code; }
325   static RuntimeBlob* continuation_stubs_code() { return _continuation_stubs_code; }
326   static RuntimeBlob* compiler_stubs_code()     { return _compiler_stubs_code; }
327   static RuntimeBlob* final_stubs_code()        { return _final_stubs_code; }
328 
329   // Debugging
330   static jint    verify_oop_count()                        { return _verify_oop_count; }
331   static jint*   verify_oop_count_addr()                   { return &_verify_oop_count; }
332   // a subroutine for debugging the GC
333   static address verify_oop_subroutine_entry_address()     { return (address)&_verify_oop_subroutine_entry; }
334 
335   static address catch_exception_entry()                   { return _catch_exception_entry; }
336 
337   // Calls to Java
338   typedef void (*CallStub)(
339     address   link,
340     intptr_t* result,
341     int       result_type, /* BasicType on 4 bytes */
342     Method* method,
343     address   entry_point,
344     intptr_t* parameters,
345     int       size_of_parameters,
346     TRAPS
347   );
348 
349   static CallStub call_stub()                              { return CAST_TO_FN_PTR(CallStub, _call_stub_entry); }
350 
351   // Exceptions
352   static address forward_exception_entry()                 { return _forward_exception_entry; }
353 
354   static address atomic_xchg_entry()                       { return _atomic_xchg_entry; }
355   static address atomic_cmpxchg_entry()                    { return _atomic_cmpxchg_entry; }
356   static address atomic_cmpxchg_long_entry()               { return _atomic_cmpxchg_long_entry; }
357   static address atomic_add_entry()                        { return _atomic_add_entry; }
358   static address fence_entry()                             { return _fence_entry; }
359 
360   static address select_arraycopy_function(BasicType t, bool aligned, bool disjoint, const char* &name, bool dest_uninitialized);
361 
362   static address jbyte_arraycopy()  { return _jbyte_arraycopy; }
363   static address jshort_arraycopy() { return _jshort_arraycopy; }
364   static address jint_arraycopy()   { return _jint_arraycopy; }
365   static address jlong_arraycopy()  { return _jlong_arraycopy; }
366   static address oop_arraycopy(bool dest_uninitialized = false) {
367     return dest_uninitialized ? _oop_arraycopy_uninit : _oop_arraycopy;
368   }
369   static address jbyte_disjoint_arraycopy()  { return _jbyte_disjoint_arraycopy; }
370   static address jshort_disjoint_arraycopy() { return _jshort_disjoint_arraycopy; }
371   static address jint_disjoint_arraycopy()   { return _jint_disjoint_arraycopy; }
372   static address jlong_disjoint_arraycopy()  { return _jlong_disjoint_arraycopy; }
373   static address oop_disjoint_arraycopy(bool dest_uninitialized = false) {
374     return dest_uninitialized ?  _oop_disjoint_arraycopy_uninit : _oop_disjoint_arraycopy;
375   }
376 
377   static address arrayof_jbyte_arraycopy()  { return _arrayof_jbyte_arraycopy; }
378   static address arrayof_jshort_arraycopy() { return _arrayof_jshort_arraycopy; }
379   static address arrayof_jint_arraycopy()   { return _arrayof_jint_arraycopy; }
380   static address arrayof_jlong_arraycopy()  { return _arrayof_jlong_arraycopy; }
381   static address arrayof_oop_arraycopy(bool dest_uninitialized = false) {
382     return dest_uninitialized ? _arrayof_oop_arraycopy_uninit : _arrayof_oop_arraycopy;
383   }
384 
385   static address arrayof_jbyte_disjoint_arraycopy()  { return _arrayof_jbyte_disjoint_arraycopy; }
386   static address arrayof_jshort_disjoint_arraycopy() { return _arrayof_jshort_disjoint_arraycopy; }
387   static address arrayof_jint_disjoint_arraycopy()   { return _arrayof_jint_disjoint_arraycopy; }
388   static address arrayof_jlong_disjoint_arraycopy()  { return _arrayof_jlong_disjoint_arraycopy; }
389   static address arrayof_oop_disjoint_arraycopy(bool dest_uninitialized = false) {
390     return dest_uninitialized ? _arrayof_oop_disjoint_arraycopy_uninit : _arrayof_oop_disjoint_arraycopy;
391   }
392   static address data_cache_writeback()              { return _data_cache_writeback; }
393   static address data_cache_writeback_sync()         { return _data_cache_writeback_sync; }
394 
395   typedef void (*DataCacheWritebackStub)(void *);
396   static DataCacheWritebackStub DataCacheWriteback_stub()         { return CAST_TO_FN_PTR(DataCacheWritebackStub,  _data_cache_writeback); }
397   typedef void (*DataCacheWritebackSyncStub)(bool);
398   static DataCacheWritebackSyncStub DataCacheWritebackSync_stub() { return CAST_TO_FN_PTR(DataCacheWritebackSyncStub,  _data_cache_writeback_sync); }
399 
400   static address checkcast_arraycopy(bool dest_uninitialized = false) {
401     return dest_uninitialized ? _checkcast_arraycopy_uninit : _checkcast_arraycopy;
402   }
403   static address unsafe_arraycopy()     { return _unsafe_arraycopy; }
404 
405   typedef void (*UnsafeArrayCopyStub)(const void* src, void* dst, size_t count);
406   static UnsafeArrayCopyStub UnsafeArrayCopy_stub()         { return CAST_TO_FN_PTR(UnsafeArrayCopyStub,  _unsafe_arraycopy); }
407 
408   static address unsafe_setmemory()     { return _unsafe_setmemory; }
409 
410   typedef void (*UnsafeSetMemoryStub)(void* dst, size_t count, char byte);
411   static UnsafeSetMemoryStub UnsafeSetMemory_stub()         { return CAST_TO_FN_PTR(UnsafeSetMemoryStub,  _unsafe_setmemory); }
412 
413   static address generic_arraycopy()   { return _generic_arraycopy; }
414   static address select_arraysort_function() { return _array_sort; }
415   static address select_array_partition_function() { return _array_partition; }
416 
417   static address jbyte_fill()          { return _jbyte_fill; }
418   static address jshort_fill()         { return _jshort_fill; }
419   static address jint_fill()           { return _jint_fill; }
420   static address arrayof_jbyte_fill()  { return _arrayof_jbyte_fill; }
421   static address arrayof_jshort_fill() { return _arrayof_jshort_fill; }
422   static address arrayof_jint_fill()   { return _arrayof_jint_fill; }
423 
424   static address aescrypt_encryptBlock()                { return _aescrypt_encryptBlock; }
425   static address aescrypt_decryptBlock()                { return _aescrypt_decryptBlock; }
426   static address cipherBlockChaining_encryptAESCrypt()  { return _cipherBlockChaining_encryptAESCrypt; }
427   static address cipherBlockChaining_decryptAESCrypt()  { return _cipherBlockChaining_decryptAESCrypt; }
428   static address electronicCodeBook_encryptAESCrypt()   { return _electronicCodeBook_encryptAESCrypt; }
429   static address electronicCodeBook_decryptAESCrypt()   { return _electronicCodeBook_decryptAESCrypt; }
430   static address poly1305_processBlocks()               { return _poly1305_processBlocks; }
431   static address intpoly_montgomeryMult_P256()          { return _intpoly_montgomeryMult_P256; }
432   static address intpoly_assign()        { return _intpoly_assign; }
433   static address counterMode_AESCrypt()  { return _counterMode_AESCrypt; }
434   static address ghash_processBlocks()   { return _ghash_processBlocks; }
435   static address chacha20Block()         { return _chacha20Block; }
436   static address base64_encodeBlock()    { return _base64_encodeBlock; }
437   static address base64_decodeBlock()    { return _base64_decodeBlock; }
438   static address md5_implCompress()      { return _md5_implCompress; }
439   static address md5_implCompressMB()    { return _md5_implCompressMB; }
440   static address sha1_implCompress()     { return _sha1_implCompress; }
441   static address sha1_implCompressMB()   { return _sha1_implCompressMB; }
442   static address sha256_implCompress()   { return _sha256_implCompress; }
443   static address sha256_implCompressMB() { return _sha256_implCompressMB; }
444   static address sha512_implCompress()   { return _sha512_implCompress; }
445   static address sha512_implCompressMB() { return _sha512_implCompressMB; }
446   static address sha3_implCompress()     { return _sha3_implCompress; }
447   static address sha3_implCompressMB()   { return _sha3_implCompressMB; }
448 
449   static address updateBytesCRC32()    { return _updateBytesCRC32; }
450   static address crc_table_addr()      { return _crc_table_adr; }
451 
452   static address crc32c_table_addr()   { return _crc32c_table_addr; }
453   static address updateBytesCRC32C()   { return _updateBytesCRC32C; }
454   static address updateBytesAdler32()  { return _updateBytesAdler32; }
455 
456   static address multiplyToLen()       { return _multiplyToLen; }
457   static address squareToLen()         { return _squareToLen; }
458   static address mulAdd()              { return _mulAdd; }
459   static address montgomeryMultiply()  { return _montgomeryMultiply; }
460   static address montgomerySquare()    { return _montgomerySquare; }
461   static address bigIntegerRightShift() { return _bigIntegerRightShiftWorker; }
462   static address bigIntegerLeftShift()  { return _bigIntegerLeftShiftWorker; }
463   static address galoisCounterMode_AESCrypt()   { return _galoisCounterMode_AESCrypt; }
464 
465   static address vectorizedMismatch()  { return _vectorizedMismatch; }
466 
467   static address dexp()                { return _dexp; }
468   static address dlog()                { return _dlog; }
469   static address dlog10()              { return _dlog10; }
470   static address dpow()                { return _dpow; }
471   static address fmod()                { return _fmod; }
472   static address dsin()                { return _dsin; }
473   static address dcos()                { return _dcos; }
474   static address dlibm_reduce_pi04l()  { return _dlibm_reduce_pi04l; }
475   static address dlibm_sin_cos_huge()  { return _dlibm_sin_cos_huge; }
476   static address dlibm_tan_cot_huge()  { return _dlibm_tan_cot_huge; }
477   static address dtan()                { return _dtan; }
478   static address dtanh()               { return _dtanh; }
479 
480   // These are versions of the java.lang.Float::floatToFloat16() and float16ToFloat()
481   // methods which perform the same operations as the intrinsic version.
482   // They are used for constant folding in JIT compiler to ensure equivalence.
483   //
484   static address f2hf_adr()            { return _f2hf; }
485   static address hf2f_adr()            { return _hf2f; }
486 
487   static jshort f2hf(jfloat x) {
488     assert(_f2hf != nullptr, "stub is not implemented on this platform");
489     MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current());) // About to call into code cache
490     typedef jshort (*f2hf_stub_t)(jfloat x);
491     return ((f2hf_stub_t)_f2hf)(x);
492   }
493   static jfloat hf2f(jshort x) {
494     assert(_hf2f != nullptr, "stub is not implemented on this platform");
495     MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current());) // About to call into code cache
496     typedef jfloat (*hf2f_stub_t)(jshort x);
497     return ((hf2f_stub_t)_hf2f)(x);
498   }
499 
500   static address method_entry_barrier() { return _method_entry_barrier; }
501 
502   static address cont_thaw()           { return _cont_thaw; }
503   static address cont_returnBarrier()  { return _cont_returnBarrier; }
504   static address cont_returnBarrierExc(){return _cont_returnBarrierExc; }
505   static address cont_preempt_stub()   { return _cont_preempt_stub; }
506 
507   static address upcall_stub_exception_handler() {
508     assert(_upcall_stub_exception_handler != nullptr, "not implemented");
509     return _upcall_stub_exception_handler;
510   }
511 
512   static address upcall_stub_load_target() {
513     assert(_upcall_stub_load_target != nullptr, "not implemented");
514     return _upcall_stub_load_target;
515   }
516 
517   static address lookup_secondary_supers_table_stub(u1 slot) {
518     assert(slot < Klass::SECONDARY_SUPERS_TABLE_SIZE, "out of bounds");
519     assert(_lookup_secondary_supers_table_stubs[slot] != nullptr, "not implemented");
520     return _lookup_secondary_supers_table_stubs[slot];
521   }
522 
523   static address lookup_secondary_supers_table_slow_path_stub() {
524     assert(_lookup_secondary_supers_table_slow_path_stub != nullptr, "not implemented");
525     return _lookup_secondary_supers_table_slow_path_stub;
526   }
527 
528   static address select_fill_function(BasicType t, bool aligned, const char* &name);
529 
530   //
531   // Default versions of the above arraycopy functions for platforms which do
532   // not have specialized versions
533   //
534   static void jbyte_copy     (jbyte*  src, jbyte*  dest, size_t count);
535   static void jshort_copy    (jshort* src, jshort* dest, size_t count);
536   static void jint_copy      (jint*   src, jint*   dest, size_t count);
537   static void jlong_copy     (jlong*  src, jlong*  dest, size_t count);
538   static void oop_copy       (oop*    src, oop*    dest, size_t count);
539   static void oop_copy_uninit(oop*    src, oop*    dest, size_t count);
540 
541   static void arrayof_jbyte_copy     (HeapWord* src, HeapWord* dest, size_t count);
542   static void arrayof_jshort_copy    (HeapWord* src, HeapWord* dest, size_t count);
543   static void arrayof_jint_copy      (HeapWord* src, HeapWord* dest, size_t count);
544   static void arrayof_jlong_copy     (HeapWord* src, HeapWord* dest, size_t count);
545   static void arrayof_oop_copy       (HeapWord* src, HeapWord* dest, size_t count);
546   static void arrayof_oop_copy_uninit(HeapWord* src, HeapWord* dest, size_t count);
547 };
548 
549 #endif // SHARE_RUNTIME_STUBROUTINES_HPP