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 #include "precompiled.hpp"
 26 #include "asm/codeBuffer.hpp"
 27 #include "asm/macroAssembler.inline.hpp"
 28 #include "memory/resourceArea.hpp"
 29 #include "oops/access.inline.hpp"
 30 #include "oops/klass.hpp"
 31 #include "oops/oop.inline.hpp"
 32 #include "prims/vectorSupport.hpp"
 33 #include "runtime/continuation.hpp"
 34 #include "runtime/interfaceSupport.inline.hpp"
 35 #include "runtime/timerTrace.hpp"
 36 #include "runtime/sharedRuntime.hpp"
 37 #include "runtime/stubRoutines.hpp"
 38 #include "utilities/align.hpp"
 39 #include "utilities/copy.hpp"
 40 #ifdef COMPILER2
 41 #include "opto/runtime.hpp"
 42 #endif
 43 
 44 UnsafeMemoryAccess* UnsafeMemoryAccess::_table                  = nullptr;
 45 int UnsafeMemoryAccess::_table_length                           = 0;
 46 int UnsafeMemoryAccess::_table_max_length                       = 0;
 47 address UnsafeMemoryAccess::_common_exit_stub_pc                = nullptr;
 48 
 49 // Implementation of StubRoutines - for a description
 50 // of how to extend it, see the header file.
 51 
 52 // Class Variables
 53 
 54 BufferBlob* StubRoutines::_initial_stubs_code                   = nullptr;
 55 BufferBlob* StubRoutines::_final_stubs_code                     = nullptr;
 56 BufferBlob* StubRoutines::_compiler_stubs_code                  = nullptr;
 57 BufferBlob* StubRoutines::_continuation_stubs_code              = nullptr;
 58 
 59 address StubRoutines::_call_stub_return_address                 = nullptr;
 60 address StubRoutines::_call_stub_entry                          = nullptr;
 61 
 62 address StubRoutines::_catch_exception_entry                    = nullptr;
 63 address StubRoutines::_forward_exception_entry                  = nullptr;
 64 jint    StubRoutines::_verify_oop_count                         = 0;
 65 address StubRoutines::_verify_oop_subroutine_entry              = nullptr;
 66 address StubRoutines::_atomic_xchg_entry                        = nullptr;
 67 address StubRoutines::_atomic_cmpxchg_entry                     = nullptr;
 68 address StubRoutines::_atomic_cmpxchg_long_entry                = nullptr;
 69 address StubRoutines::_atomic_add_entry                         = nullptr;
 70 address StubRoutines::_fence_entry                              = nullptr;
 71 
 72 // Compiled code entry points default values
 73 // The default functions don't have separate disjoint versions.
 74 address StubRoutines::_jbyte_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jbyte_copy);
 75 address StubRoutines::_jshort_arraycopy         = CAST_FROM_FN_PTR(address, StubRoutines::jshort_copy);
 76 address StubRoutines::_jint_arraycopy           = CAST_FROM_FN_PTR(address, StubRoutines::jint_copy);
 77 address StubRoutines::_jlong_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jlong_copy);
 78 address StubRoutines::_oop_arraycopy            = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy);
 79 address StubRoutines::_oop_arraycopy_uninit     = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy_uninit);
 80 address StubRoutines::_jbyte_disjoint_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jbyte_copy);
 81 address StubRoutines::_jshort_disjoint_arraycopy         = CAST_FROM_FN_PTR(address, StubRoutines::jshort_copy);
 82 address StubRoutines::_jint_disjoint_arraycopy           = CAST_FROM_FN_PTR(address, StubRoutines::jint_copy);
 83 address StubRoutines::_jlong_disjoint_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jlong_copy);
 84 address StubRoutines::_oop_disjoint_arraycopy            = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy);
 85 address StubRoutines::_oop_disjoint_arraycopy_uninit     = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy_uninit);
 86 
 87 address StubRoutines::_arrayof_jbyte_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jbyte_copy);
 88 address StubRoutines::_arrayof_jshort_arraycopy = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jshort_copy);
 89 address StubRoutines::_arrayof_jint_arraycopy   = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jint_copy);
 90 address StubRoutines::_arrayof_jlong_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jlong_copy);
 91 address StubRoutines::_arrayof_oop_arraycopy    = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy);
 92 address StubRoutines::_arrayof_oop_arraycopy_uninit      = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy_uninit);
 93 address StubRoutines::_arrayof_jbyte_disjoint_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jbyte_copy);
 94 address StubRoutines::_arrayof_jshort_disjoint_arraycopy = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jshort_copy);
 95 address StubRoutines::_arrayof_jint_disjoint_arraycopy   = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jint_copy);
 96 address StubRoutines::_arrayof_jlong_disjoint_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jlong_copy);
 97 address StubRoutines::_arrayof_oop_disjoint_arraycopy    = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy);
 98 address StubRoutines::_arrayof_oop_disjoint_arraycopy_uninit  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy_uninit);
 99 
100 address StubRoutines::_data_cache_writeback              = nullptr;
101 address StubRoutines::_data_cache_writeback_sync         = nullptr;
102 
103 address StubRoutines::_checkcast_arraycopy               = nullptr;
104 address StubRoutines::_checkcast_arraycopy_uninit        = nullptr;
105 address StubRoutines::_unsafe_arraycopy                  = nullptr;
106 address StubRoutines::_generic_arraycopy                 = nullptr;
107 
108 address StubRoutines::_unsafe_setmemory                  = nullptr;
109 
110 address StubRoutines::_jbyte_fill;
111 address StubRoutines::_jshort_fill;
112 address StubRoutines::_jint_fill;
113 address StubRoutines::_arrayof_jbyte_fill;
114 address StubRoutines::_arrayof_jshort_fill;
115 address StubRoutines::_arrayof_jint_fill;
116 
117 address StubRoutines::_aescrypt_encryptBlock               = nullptr;
118 address StubRoutines::_aescrypt_decryptBlock               = nullptr;
119 address StubRoutines::_cipherBlockChaining_encryptAESCrypt = nullptr;
120 address StubRoutines::_cipherBlockChaining_decryptAESCrypt = nullptr;
121 address StubRoutines::_electronicCodeBook_encryptAESCrypt  = nullptr;
122 address StubRoutines::_electronicCodeBook_decryptAESCrypt  = nullptr;
123 address StubRoutines::_counterMode_AESCrypt                = nullptr;
124 address StubRoutines::_galoisCounterMode_AESCrypt          = nullptr;
125 address StubRoutines::_ghash_processBlocks                 = nullptr;
126 address StubRoutines::_chacha20Block                       = nullptr;
127 address StubRoutines::_base64_encodeBlock                  = nullptr;
128 address StubRoutines::_base64_decodeBlock                  = nullptr;
129 address StubRoutines::_poly1305_processBlocks              = nullptr;
130 address StubRoutines::_intpoly_montgomeryMult_P256         = nullptr;
131 address StubRoutines::_intpoly_assign                      = nullptr;
132 
133 address StubRoutines::_md5_implCompress      = nullptr;
134 address StubRoutines::_md5_implCompressMB    = nullptr;
135 address StubRoutines::_sha1_implCompress     = nullptr;
136 address StubRoutines::_sha1_implCompressMB   = nullptr;
137 address StubRoutines::_sha256_implCompress   = nullptr;
138 address StubRoutines::_sha256_implCompressMB = nullptr;
139 address StubRoutines::_sha512_implCompress   = nullptr;
140 address StubRoutines::_sha512_implCompressMB = nullptr;
141 address StubRoutines::_sha3_implCompress     = nullptr;
142 address StubRoutines::_sha3_implCompressMB   = nullptr;
143 
144 address StubRoutines::_updateBytesCRC32 = nullptr;
145 address StubRoutines::_crc_table_adr =    nullptr;
146 
147 address StubRoutines::_string_indexof_array[4]   =    { nullptr };
148 
149 address StubRoutines::_crc32c_table_addr = nullptr;
150 address StubRoutines::_updateBytesCRC32C = nullptr;
151 address StubRoutines::_updateBytesAdler32 = nullptr;
152 
153 address StubRoutines::_multiplyToLen = nullptr;
154 address StubRoutines::_squareToLen = nullptr;
155 address StubRoutines::_mulAdd = nullptr;
156 address StubRoutines::_montgomeryMultiply = nullptr;
157 address StubRoutines::_montgomerySquare = nullptr;
158 address StubRoutines::_bigIntegerRightShiftWorker = nullptr;
159 address StubRoutines::_bigIntegerLeftShiftWorker = nullptr;
160 
161 address StubRoutines::_vectorizedMismatch = nullptr;
162 
163 address StubRoutines::_dexp = nullptr;
164 address StubRoutines::_dlog = nullptr;
165 address StubRoutines::_dlog10 = nullptr;
166 address StubRoutines::_fmod = nullptr;
167 address StubRoutines::_dpow = nullptr;
168 address StubRoutines::_dsin = nullptr;
169 address StubRoutines::_dcos = nullptr;
170 address StubRoutines::_dlibm_sin_cos_huge = nullptr;
171 address StubRoutines::_dlibm_reduce_pi04l = nullptr;
172 address StubRoutines::_dlibm_tan_cot_huge = nullptr;
173 address StubRoutines::_dtan = nullptr;
174 address StubRoutines::_dtanh = nullptr;
175 
176 address StubRoutines::_f2hf = nullptr;
177 address StubRoutines::_hf2f = nullptr;
178 
179 address StubRoutines::_vector_f_math[VectorSupport::NUM_VEC_SIZES][VectorSupport::NUM_VECTOR_OP_MATH] = {{nullptr}, {nullptr}};
180 address StubRoutines::_vector_d_math[VectorSupport::NUM_VEC_SIZES][VectorSupport::NUM_VECTOR_OP_MATH] = {{nullptr}, {nullptr}};
181 
182 address StubRoutines::_method_entry_barrier = nullptr;
183 address StubRoutines::_array_sort = nullptr;
184 address StubRoutines::_array_partition  = nullptr;
185 
186 address StubRoutines::_cont_thaw          = nullptr;
187 address StubRoutines::_cont_returnBarrier = nullptr;
188 address StubRoutines::_cont_returnBarrierExc = nullptr;
189 
190 address StubRoutines::_upcall_stub_exception_handler = nullptr;
191 address StubRoutines::_upcall_stub_load_target = nullptr;
192 
193 address StubRoutines::_lookup_secondary_supers_table_slow_path_stub = nullptr;
194 address StubRoutines::_lookup_secondary_supers_table_stubs[Klass::SECONDARY_SUPERS_TABLE_SIZE] = { nullptr };
195 
196 
197 // Initialization
198 //
199 // Note: to break cycle with universe initialization, stubs are generated in two phases.
200 // The first one generates stubs needed during universe init (e.g., _handle_must_compile_first_entry).
201 // The second phase includes all other stubs (which may depend on universe being initialized.)
202 
203 extern void StubGenerator_generate(CodeBuffer* code, StubCodeGenerator::StubsKind kind); // only interface to generators
204 
205 void UnsafeMemoryAccess::create_table(int max_size) {
206   UnsafeMemoryAccess::_table = new UnsafeMemoryAccess[max_size];
207   UnsafeMemoryAccess::_table_max_length = max_size;
208 }
209 
210 bool UnsafeMemoryAccess::contains_pc(address pc) {
211   for (int i = 0; i < UnsafeMemoryAccess::_table_length; i++) {
212     UnsafeMemoryAccess* entry = &UnsafeMemoryAccess::_table[i];
213     if (pc >= entry->start_pc() && pc < entry->end_pc()) {
214       return true;
215     }
216   }
217   return false;
218 }
219 
220 address UnsafeMemoryAccess::page_error_continue_pc(address pc) {
221   for (int i = 0; i < UnsafeMemoryAccess::_table_length; i++) {
222     UnsafeMemoryAccess* entry = &UnsafeMemoryAccess::_table[i];
223     if (pc >= entry->start_pc() && pc < entry->end_pc()) {
224       return entry->error_exit_pc();
225     }
226   }
227   return nullptr;
228 }
229 
230 
231 static BufferBlob* initialize_stubs(StubCodeGenerator::StubsKind kind,
232                                     int code_size, int max_aligned_stubs,
233                                     const char* timer_msg,
234                                     const char* buffer_name,
235                                     const char* assert_msg) {
236   ResourceMark rm;
237   TraceTime timer(timer_msg, TRACETIME_LOG(Info, startuptime));
238   // Add extra space for large CodeEntryAlignment
239   int size = code_size + CodeEntryAlignment * max_aligned_stubs;
240   BufferBlob* stubs_code = BufferBlob::create(buffer_name, size);
241   if (stubs_code == nullptr) {
242     vm_exit_out_of_memory(code_size, OOM_MALLOC_ERROR, "CodeCache: no room for %s", buffer_name);
243   }
244   CodeBuffer buffer(stubs_code);
245   StubGenerator_generate(&buffer, kind);
246   // When new stubs added we need to make sure there is some space left
247   // to catch situation when we should increase size again.
248   assert(code_size == 0 || buffer.insts_remaining() > 200, "increase %s", assert_msg);
249 
250   LogTarget(Info, stubs) lt;
251   if (lt.is_enabled()) {
252     LogStream ls(lt);
253     ls.print_cr("%s\t [" INTPTR_FORMAT ", " INTPTR_FORMAT "] used: %d, free: %d",
254                 buffer_name, p2i(stubs_code->content_begin()), p2i(stubs_code->content_end()),
255                 buffer.total_content_size(), buffer.insts_remaining());
256   }
257   return stubs_code;
258 }
259 
260 void StubRoutines::initialize_initial_stubs() {
261   if (_initial_stubs_code == nullptr) {
262     _initial_stubs_code = initialize_stubs(StubCodeGenerator::Initial_stubs,
263                                            _initial_stubs_code_size, 10,
264                                            "StubRoutines generation initial stubs",
265                                            "StubRoutines (initial stubs)",
266                                            "_initial_stubs_code_size");
267   }
268 }
269 
270 void StubRoutines::initialize_continuation_stubs() {
271   if (_continuation_stubs_code == nullptr) {
272     _continuation_stubs_code = initialize_stubs(StubCodeGenerator::Continuation_stubs,
273                                            _continuation_stubs_code_size, 10,
274                                            "StubRoutines generation continuation stubs",
275                                            "StubRoutines (continuation stubs)",
276                                            "_continuation_stubs_code_size");
277   }
278 }
279 
280 void StubRoutines::initialize_compiler_stubs() {
281   if (_compiler_stubs_code == nullptr) {
282     _compiler_stubs_code = initialize_stubs(StubCodeGenerator::Compiler_stubs,
283                                            _compiler_stubs_code_size, 100,
284                                            "StubRoutines generation compiler stubs",
285                                            "StubRoutines (compiler stubs)",
286                                            "_compiler_stubs_code_size");
287   }
288 }
289 
290 void StubRoutines::initialize_final_stubs() {
291   if (_final_stubs_code == nullptr) {
292     _final_stubs_code = initialize_stubs(StubCodeGenerator::Final_stubs,
293                                          _final_stubs_code_size, 10,
294                                          "StubRoutines generation final stubs",
295                                          "StubRoutines (final stubs)",
296                                          "_final_stubs_code_size");
297   }
298 }
299 
300 void initial_stubs_init()      { StubRoutines::initialize_initial_stubs(); }
301 void continuation_stubs_init() { StubRoutines::initialize_continuation_stubs(); }
302 void final_stubs_init()        { StubRoutines::initialize_final_stubs(); }
303 
304 void compiler_stubs_init(bool in_compiler_thread) {
305   if (in_compiler_thread && DelayCompilerStubsGeneration) {
306     // Temporarily revert state of stubs generation because
307     // it is called after final_stubs_init() finished
308     // during compiler runtime initialization.
309     // It is fine because these stubs are only used by
310     // compiled code and compiler is not running yet.
311     StubCodeDesc::unfreeze();
312     StubRoutines::initialize_compiler_stubs();
313     StubCodeDesc::freeze();
314   } else if (!in_compiler_thread && !DelayCompilerStubsGeneration) {
315     StubRoutines::initialize_compiler_stubs();
316   }
317 }
318 
319 //
320 // Default versions of arraycopy functions
321 //
322 
323 JRT_LEAF(void, StubRoutines::jbyte_copy(jbyte* src, jbyte* dest, size_t count))
324 #ifndef PRODUCT
325   SharedRuntime::_jbyte_array_copy_ctr++;      // Slow-path byte array copy
326 #endif // !PRODUCT
327   Copy::conjoint_jbytes_atomic(src, dest, count);
328 JRT_END
329 
330 JRT_LEAF(void, StubRoutines::jshort_copy(jshort* src, jshort* dest, size_t count))
331 #ifndef PRODUCT
332   SharedRuntime::_jshort_array_copy_ctr++;     // Slow-path short/char array copy
333 #endif // !PRODUCT
334   Copy::conjoint_jshorts_atomic(src, dest, count);
335 JRT_END
336 
337 JRT_LEAF(void, StubRoutines::jint_copy(jint* src, jint* dest, size_t count))
338 #ifndef PRODUCT
339   SharedRuntime::_jint_array_copy_ctr++;       // Slow-path int/float array copy
340 #endif // !PRODUCT
341   Copy::conjoint_jints_atomic(src, dest, count);
342 JRT_END
343 
344 JRT_LEAF(void, StubRoutines::jlong_copy(jlong* src, jlong* dest, size_t count))
345 #ifndef PRODUCT
346   SharedRuntime::_jlong_array_copy_ctr++;      // Slow-path long/double array copy
347 #endif // !PRODUCT
348   Copy::conjoint_jlongs_atomic(src, dest, count);
349 JRT_END
350 
351 JRT_LEAF(void, StubRoutines::oop_copy(oop* src, oop* dest, size_t count))
352 #ifndef PRODUCT
353   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
354 #endif // !PRODUCT
355   assert(count != 0, "count should be non-zero");
356   ArrayAccess<>::oop_arraycopy_raw((HeapWord*)src, (HeapWord*)dest, count);
357 JRT_END
358 
359 JRT_LEAF(void, StubRoutines::oop_copy_uninit(oop* src, oop* dest, size_t count))
360 #ifndef PRODUCT
361   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
362 #endif // !PRODUCT
363   assert(count != 0, "count should be non-zero");
364   ArrayAccess<IS_DEST_UNINITIALIZED>::oop_arraycopy_raw((HeapWord*)src, (HeapWord*)dest, count);
365 JRT_END
366 
367 JRT_LEAF(void, StubRoutines::arrayof_jbyte_copy(HeapWord* src, HeapWord* dest, size_t count))
368 #ifndef PRODUCT
369   SharedRuntime::_jbyte_array_copy_ctr++;      // Slow-path byte array copy
370 #endif // !PRODUCT
371   Copy::arrayof_conjoint_jbytes(src, dest, count);
372 JRT_END
373 
374 JRT_LEAF(void, StubRoutines::arrayof_jshort_copy(HeapWord* src, HeapWord* dest, size_t count))
375 #ifndef PRODUCT
376   SharedRuntime::_jshort_array_copy_ctr++;     // Slow-path short/char array copy
377 #endif // !PRODUCT
378   Copy::arrayof_conjoint_jshorts(src, dest, count);
379 JRT_END
380 
381 JRT_LEAF(void, StubRoutines::arrayof_jint_copy(HeapWord* src, HeapWord* dest, size_t count))
382 #ifndef PRODUCT
383   SharedRuntime::_jint_array_copy_ctr++;       // Slow-path int/float array copy
384 #endif // !PRODUCT
385   Copy::arrayof_conjoint_jints(src, dest, count);
386 JRT_END
387 
388 JRT_LEAF(void, StubRoutines::arrayof_jlong_copy(HeapWord* src, HeapWord* dest, size_t count))
389 #ifndef PRODUCT
390   SharedRuntime::_jlong_array_copy_ctr++;       // Slow-path int/float array copy
391 #endif // !PRODUCT
392   Copy::arrayof_conjoint_jlongs(src, dest, count);
393 JRT_END
394 
395 JRT_LEAF(void, StubRoutines::arrayof_oop_copy(HeapWord* src, HeapWord* dest, size_t count))
396 #ifndef PRODUCT
397   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
398 #endif // !PRODUCT
399   assert(count != 0, "count should be non-zero");
400   ArrayAccess<ARRAYCOPY_ARRAYOF>::oop_arraycopy_raw(src, dest, count);
401 JRT_END
402 
403 JRT_LEAF(void, StubRoutines::arrayof_oop_copy_uninit(HeapWord* src, HeapWord* dest, size_t count))
404 #ifndef PRODUCT
405   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
406 #endif // !PRODUCT
407   assert(count != 0, "count should be non-zero");
408   ArrayAccess<ARRAYCOPY_ARRAYOF | IS_DEST_UNINITIALIZED>::oop_arraycopy_raw(src, dest, count);
409 JRT_END
410 
411 address StubRoutines::select_fill_function(BasicType t, bool aligned, const char* &name) {
412 #define RETURN_STUB(xxx_fill) { \
413   name = #xxx_fill; \
414   return StubRoutines::xxx_fill(); }
415 
416   switch (t) {
417   case T_BYTE:
418   case T_BOOLEAN:
419     if (!aligned) RETURN_STUB(jbyte_fill);
420     RETURN_STUB(arrayof_jbyte_fill);
421   case T_CHAR:
422   case T_SHORT:
423     if (!aligned) RETURN_STUB(jshort_fill);
424     RETURN_STUB(arrayof_jshort_fill);
425   case T_INT:
426   case T_FLOAT:
427     if (!aligned) RETURN_STUB(jint_fill);
428     RETURN_STUB(arrayof_jint_fill);
429   case T_DOUBLE:
430   case T_LONG:
431   case T_ARRAY:
432   case T_OBJECT:
433   case T_NARROWOOP:
434   case T_NARROWKLASS:
435   case T_ADDRESS:
436   case T_VOID:
437     // Currently unsupported
438     return nullptr;
439 
440   default:
441     ShouldNotReachHere();
442     return nullptr;
443   }
444 
445 #undef RETURN_STUB
446 }
447 
448 // constants for computing the copy function
449 enum {
450   COPYFUNC_UNALIGNED = 0,
451   COPYFUNC_ALIGNED = 1,                 // src, dest aligned to HeapWordSize
452   COPYFUNC_CONJOINT = 0,
453   COPYFUNC_DISJOINT = 2                 // src != dest, or transfer can descend
454 };
455 
456 // Note:  The condition "disjoint" applies also for overlapping copies
457 // where an descending copy is permitted (i.e., dest_offset <= src_offset).
458 address
459 StubRoutines::select_arraycopy_function(BasicType t, bool aligned, bool disjoint, const char* &name, bool dest_uninitialized) {
460   int selector =
461     (aligned  ? COPYFUNC_ALIGNED  : COPYFUNC_UNALIGNED) +
462     (disjoint ? COPYFUNC_DISJOINT : COPYFUNC_CONJOINT);
463 
464 #define RETURN_STUB(xxx_arraycopy) { \
465   name = #xxx_arraycopy; \
466   return StubRoutines::xxx_arraycopy(); }
467 
468 #define RETURN_STUB_PARM(xxx_arraycopy, parm) { \
469   name = parm ? #xxx_arraycopy "_uninit": #xxx_arraycopy; \
470   return StubRoutines::xxx_arraycopy(parm); }
471 
472   switch (t) {
473   case T_BYTE:
474   case T_BOOLEAN:
475     switch (selector) {
476     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jbyte_arraycopy);
477     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jbyte_arraycopy);
478     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jbyte_disjoint_arraycopy);
479     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jbyte_disjoint_arraycopy);
480     }
481   case T_CHAR:
482   case T_SHORT:
483     switch (selector) {
484     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jshort_arraycopy);
485     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jshort_arraycopy);
486     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jshort_disjoint_arraycopy);
487     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jshort_disjoint_arraycopy);
488     }
489   case T_INT:
490   case T_FLOAT:
491     switch (selector) {
492     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jint_arraycopy);
493     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jint_arraycopy);
494     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jint_disjoint_arraycopy);
495     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jint_disjoint_arraycopy);
496     }
497   case T_DOUBLE:
498   case T_LONG:
499     switch (selector) {
500     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jlong_arraycopy);
501     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jlong_arraycopy);
502     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jlong_disjoint_arraycopy);
503     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jlong_disjoint_arraycopy);
504     }
505   case T_ARRAY:
506   case T_OBJECT:
507     switch (selector) {
508     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB_PARM(oop_arraycopy, dest_uninitialized);
509     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB_PARM(arrayof_oop_arraycopy, dest_uninitialized);
510     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB_PARM(oop_disjoint_arraycopy, dest_uninitialized);
511     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB_PARM(arrayof_oop_disjoint_arraycopy, dest_uninitialized);
512     }
513   default:
514     ShouldNotReachHere();
515     return nullptr;
516   }
517 
518 #undef RETURN_STUB
519 #undef RETURN_STUB_PARM
520 }
521 
522 UnsafeMemoryAccessMark::UnsafeMemoryAccessMark(StubCodeGenerator* cgen, bool add_entry, bool continue_at_scope_end, address error_exit_pc) {
523   _cgen = cgen;
524   _ucm_entry = nullptr;
525   if (add_entry) {
526     address err_exit_pc = nullptr;
527     if (!continue_at_scope_end) {
528       err_exit_pc = error_exit_pc != nullptr ? error_exit_pc : UnsafeMemoryAccess::common_exit_stub_pc();
529     }
530     assert(err_exit_pc != nullptr || continue_at_scope_end, "error exit not set");
531     _ucm_entry = UnsafeMemoryAccess::add_to_table(_cgen->assembler()->pc(), nullptr, err_exit_pc);
532   }
533 }
534 
535 UnsafeMemoryAccessMark::~UnsafeMemoryAccessMark() {
536   if (_ucm_entry != nullptr) {
537     _ucm_entry->set_end_pc(_cgen->assembler()->pc());
538     if (_ucm_entry->error_exit_pc() == nullptr) {
539       _ucm_entry->set_error_exit_pc(_cgen->assembler()->pc());
540     }
541   }
542 }