1 /*
  2  * Copyright (c) 1997, 2023, 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/oop.inline.hpp"
 31 #include "prims/vectorSupport.hpp"
 32 #include "runtime/continuation.hpp"
 33 #include "runtime/interfaceSupport.inline.hpp"
 34 #include "runtime/timerTrace.hpp"
 35 #include "runtime/sharedRuntime.hpp"
 36 #include "runtime/stubRoutines.hpp"
 37 #include "utilities/align.hpp"
 38 #include "utilities/copy.hpp"
 39 #ifdef COMPILER2
 40 #include "opto/runtime.hpp"
 41 #endif
 42 
 43 UnsafeCopyMemory* UnsafeCopyMemory::_table                      = nullptr;
 44 int UnsafeCopyMemory::_table_length                             = 0;
 45 int UnsafeCopyMemory::_table_max_length                         = 0;
 46 address UnsafeCopyMemory::_common_exit_stub_pc                  = nullptr;
 47 
 48 // Implementation of StubRoutines - for a description
 49 // of how to extend it, see the header file.
 50 
 51 // Class Variables
 52 
 53 BufferBlob* StubRoutines::_initial_stubs_code                   = nullptr;
 54 BufferBlob* StubRoutines::_final_stubs_code                     = nullptr;
 55 BufferBlob* StubRoutines::_compiler_stubs_code                  = nullptr;
 56 BufferBlob* StubRoutines::_continuation_stubs_code              = nullptr;
 57 
 58 address StubRoutines::_call_stub_return_address                 = nullptr;
 59 address StubRoutines::_call_stub_entry                          = nullptr;
 60 
 61 address StubRoutines::_catch_exception_entry                    = nullptr;
 62 address StubRoutines::_forward_exception_entry                  = nullptr;
 63 address StubRoutines::_throw_AbstractMethodError_entry          = nullptr;
 64 address StubRoutines::_throw_IncompatibleClassChangeError_entry = nullptr;
 65 address StubRoutines::_throw_NullPointerException_at_call_entry = nullptr;
 66 address StubRoutines::_throw_StackOverflowError_entry           = nullptr;
 67 address StubRoutines::_throw_delayed_StackOverflowError_entry   = nullptr;
 68 jint    StubRoutines::_verify_oop_count                         = 0;
 69 address StubRoutines::_verify_oop_subroutine_entry              = nullptr;
 70 address StubRoutines::_atomic_xchg_entry                        = nullptr;
 71 address StubRoutines::_atomic_cmpxchg_entry                     = nullptr;
 72 address StubRoutines::_atomic_cmpxchg_long_entry                = nullptr;
 73 address StubRoutines::_atomic_add_entry                         = nullptr;
 74 address StubRoutines::_fence_entry                              = nullptr;
 75 
 76 // Compiled code entry points default values
 77 // The default functions don't have separate disjoint versions.
 78 address StubRoutines::_jbyte_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jbyte_copy);
 79 address StubRoutines::_jshort_arraycopy         = CAST_FROM_FN_PTR(address, StubRoutines::jshort_copy);
 80 address StubRoutines::_jint_arraycopy           = CAST_FROM_FN_PTR(address, StubRoutines::jint_copy);
 81 address StubRoutines::_jlong_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jlong_copy);
 82 address StubRoutines::_oop_arraycopy            = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy);
 83 address StubRoutines::_oop_arraycopy_uninit     = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy_uninit);
 84 address StubRoutines::_jbyte_disjoint_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jbyte_copy);
 85 address StubRoutines::_jshort_disjoint_arraycopy         = CAST_FROM_FN_PTR(address, StubRoutines::jshort_copy);
 86 address StubRoutines::_jint_disjoint_arraycopy           = CAST_FROM_FN_PTR(address, StubRoutines::jint_copy);
 87 address StubRoutines::_jlong_disjoint_arraycopy          = CAST_FROM_FN_PTR(address, StubRoutines::jlong_copy);
 88 address StubRoutines::_oop_disjoint_arraycopy            = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy);
 89 address StubRoutines::_oop_disjoint_arraycopy_uninit     = CAST_FROM_FN_PTR(address, StubRoutines::oop_copy_uninit);
 90 
 91 address StubRoutines::_arrayof_jbyte_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jbyte_copy);
 92 address StubRoutines::_arrayof_jshort_arraycopy = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jshort_copy);
 93 address StubRoutines::_arrayof_jint_arraycopy   = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jint_copy);
 94 address StubRoutines::_arrayof_jlong_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jlong_copy);
 95 address StubRoutines::_arrayof_oop_arraycopy    = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy);
 96 address StubRoutines::_arrayof_oop_arraycopy_uninit      = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy_uninit);
 97 address StubRoutines::_arrayof_jbyte_disjoint_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jbyte_copy);
 98 address StubRoutines::_arrayof_jshort_disjoint_arraycopy = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jshort_copy);
 99 address StubRoutines::_arrayof_jint_disjoint_arraycopy   = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jint_copy);
100 address StubRoutines::_arrayof_jlong_disjoint_arraycopy  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_jlong_copy);
101 address StubRoutines::_arrayof_oop_disjoint_arraycopy    = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy);
102 address StubRoutines::_arrayof_oop_disjoint_arraycopy_uninit  = CAST_FROM_FN_PTR(address, StubRoutines::arrayof_oop_copy_uninit);
103 
104 address StubRoutines::_data_cache_writeback              = nullptr;
105 address StubRoutines::_data_cache_writeback_sync         = nullptr;
106 
107 address StubRoutines::_checkcast_arraycopy               = nullptr;
108 address StubRoutines::_checkcast_arraycopy_uninit        = nullptr;
109 address StubRoutines::_unsafe_arraycopy                  = nullptr;
110 address StubRoutines::_generic_arraycopy                 = nullptr;
111 
112 address StubRoutines::_jbyte_fill;
113 address StubRoutines::_jshort_fill;
114 address StubRoutines::_jint_fill;
115 address StubRoutines::_arrayof_jbyte_fill;
116 address StubRoutines::_arrayof_jshort_fill;
117 address StubRoutines::_arrayof_jint_fill;
118 
119 address StubRoutines::_aescrypt_encryptBlock               = nullptr;
120 address StubRoutines::_aescrypt_decryptBlock               = nullptr;
121 address StubRoutines::_cipherBlockChaining_encryptAESCrypt = nullptr;
122 address StubRoutines::_cipherBlockChaining_decryptAESCrypt = nullptr;
123 address StubRoutines::_electronicCodeBook_encryptAESCrypt  = nullptr;
124 address StubRoutines::_electronicCodeBook_decryptAESCrypt  = nullptr;
125 address StubRoutines::_counterMode_AESCrypt                = nullptr;
126 address StubRoutines::_galoisCounterMode_AESCrypt          = nullptr;
127 address StubRoutines::_ghash_processBlocks                 = nullptr;
128 address StubRoutines::_chacha20Block                       = nullptr;
129 address StubRoutines::_base64_encodeBlock                  = nullptr;
130 address StubRoutines::_base64_decodeBlock                  = nullptr;
131 address StubRoutines::_poly1305_processBlocks              = 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::_crc32c_table_addr = nullptr;
148 address StubRoutines::_updateBytesCRC32C = nullptr;
149 address StubRoutines::_updateBytesAdler32 = nullptr;
150 
151 address StubRoutines::_multiplyToLen = nullptr;
152 address StubRoutines::_squareToLen = nullptr;
153 address StubRoutines::_mulAdd = nullptr;
154 address StubRoutines::_montgomeryMultiply = nullptr;
155 address StubRoutines::_montgomerySquare = nullptr;
156 address StubRoutines::_bigIntegerRightShiftWorker = nullptr;
157 address StubRoutines::_bigIntegerLeftShiftWorker = nullptr;
158 
159 address StubRoutines::_vectorizedMismatch = nullptr;
160 
161 address StubRoutines::_dexp = nullptr;
162 address StubRoutines::_dlog = nullptr;
163 address StubRoutines::_dlog10 = nullptr;
164 address StubRoutines::_fmod = nullptr;
165 address StubRoutines::_dpow = nullptr;
166 address StubRoutines::_dsin = nullptr;
167 address StubRoutines::_dcos = nullptr;
168 address StubRoutines::_dlibm_sin_cos_huge = nullptr;
169 address StubRoutines::_dlibm_reduce_pi04l = nullptr;
170 address StubRoutines::_dlibm_tan_cot_huge = nullptr;
171 address StubRoutines::_dtan = nullptr;
172 
173 address StubRoutines::_f2hf = nullptr;
174 address StubRoutines::_hf2f = nullptr;
175 
176 address StubRoutines::_vector_f_math[VectorSupport::NUM_VEC_SIZES][VectorSupport::NUM_SVML_OP] = {{nullptr}, {nullptr}};
177 address StubRoutines::_vector_d_math[VectorSupport::NUM_VEC_SIZES][VectorSupport::NUM_SVML_OP] = {{nullptr}, {nullptr}};
178 
179 address StubRoutines::_method_entry_barrier = nullptr;
180 address StubRoutines::_array_sort = nullptr;
181 address StubRoutines::_array_partition  = nullptr;
182 
183 address StubRoutines::_cont_thaw          = nullptr;
184 address StubRoutines::_cont_returnBarrier = nullptr;
185 address StubRoutines::_cont_returnBarrierExc = nullptr;
186 
187 JFR_ONLY(RuntimeStub* StubRoutines::_jfr_write_checkpoint_stub = nullptr;)
188 JFR_ONLY(address StubRoutines::_jfr_write_checkpoint = nullptr;)
189 JFR_ONLY(RuntimeStub* StubRoutines::_jfr_return_lease_stub = nullptr;)
190 JFR_ONLY(address StubRoutines::_jfr_return_lease = nullptr;)
191 
192 address StubRoutines::_upcall_stub_exception_handler = nullptr;
193 
194 // Initialization
195 //
196 // Note: to break cycle with universe initialization, stubs are generated in two phases.
197 // The first one generates stubs needed during universe init (e.g., _handle_must_compile_first_entry).
198 // The second phase includes all other stubs (which may depend on universe being initialized.)
199 
200 extern void StubGenerator_generate(CodeBuffer* code, StubCodeGenerator::StubsKind kind); // only interface to generators
201 
202 void UnsafeCopyMemory::create_table(int max_size) {
203   UnsafeCopyMemory::_table = new UnsafeCopyMemory[max_size];
204   UnsafeCopyMemory::_table_max_length = max_size;
205 }
206 
207 bool UnsafeCopyMemory::contains_pc(address pc) {
208   for (int i = 0; i < UnsafeCopyMemory::_table_length; i++) {
209     UnsafeCopyMemory* entry = &UnsafeCopyMemory::_table[i];
210     if (pc >= entry->start_pc() && pc < entry->end_pc()) {
211       return true;
212     }
213   }
214   return false;
215 }
216 
217 address UnsafeCopyMemory::page_error_continue_pc(address pc) {
218   for (int i = 0; i < UnsafeCopyMemory::_table_length; i++) {
219     UnsafeCopyMemory* entry = &UnsafeCopyMemory::_table[i];
220     if (pc >= entry->start_pc() && pc < entry->end_pc()) {
221       return entry->error_exit_pc();
222     }
223   }
224   return nullptr;
225 }
226 
227 
228 static BufferBlob* initialize_stubs(StubCodeGenerator::StubsKind kind,
229                                     int code_size, int max_aligned_stubs,
230                                     const char* timer_msg,
231                                     const char* buffer_name,
232                                     const char* assert_msg) {
233   ResourceMark rm;
234   TraceTime timer(timer_msg, TRACETIME_LOG(Info, startuptime));
235   // Add extra space for large CodeEntryAlignment
236   int size = code_size + CodeEntryAlignment * max_aligned_stubs;
237   BufferBlob* stubs_code = BufferBlob::create(buffer_name, size);
238   if (stubs_code == nullptr) {
239     vm_exit_out_of_memory(code_size, OOM_MALLOC_ERROR, "CodeCache: no room for %s", buffer_name);
240   }
241   CodeBuffer buffer(stubs_code);
242   StubGenerator_generate(&buffer, kind);
243   // When new stubs added we need to make sure there is some space left
244   // to catch situation when we should increase size again.
245   assert(code_size == 0 || buffer.insts_remaining() > 200, "increase %s", assert_msg);
246 
247   LogTarget(Info, stubs) lt;
248   if (lt.is_enabled()) {
249     LogStream ls(lt);
250     ls.print_cr("%s\t [" INTPTR_FORMAT ", " INTPTR_FORMAT "] used: %d, free: %d",
251                 buffer_name, p2i(stubs_code->content_begin()), p2i(stubs_code->content_end()),
252                 buffer.total_content_size(), buffer.insts_remaining());
253   }
254   return stubs_code;
255 }
256 
257 void StubRoutines::initialize_initial_stubs() {
258   if (_initial_stubs_code == nullptr) {
259     _initial_stubs_code = initialize_stubs(StubCodeGenerator::Initial_stubs,
260                                            _initial_stubs_code_size, 10,
261                                            "StubRoutines generation initial stubs",
262                                            "StubRoutines (initial stubs)",
263                                            "_initial_stubs_code_size");
264   }
265 }
266 
267 void StubRoutines::initialize_continuation_stubs() {
268   if (_continuation_stubs_code == nullptr) {
269     _continuation_stubs_code = initialize_stubs(StubCodeGenerator::Continuation_stubs,
270                                            _continuation_stubs_code_size, 10,
271                                            "StubRoutines generation continuation stubs",
272                                            "StubRoutines (continuation stubs)",
273                                            "_continuation_stubs_code_size");
274   }
275 }
276 
277 void StubRoutines::initialize_compiler_stubs() {
278   if (_compiler_stubs_code == nullptr) {
279     _compiler_stubs_code = initialize_stubs(StubCodeGenerator::Compiler_stubs,
280                                            _compiler_stubs_code_size, 100,
281                                            "StubRoutines generation compiler stubs",
282                                            "StubRoutines (compiler stubs)",
283                                            "_compiler_stubs_code_size");
284   }
285 }
286 
287 void StubRoutines::initialize_final_stubs() {
288   if (_final_stubs_code == nullptr) {
289     _final_stubs_code = initialize_stubs(StubCodeGenerator::Final_stubs,
290                                          _final_stubs_code_size, 10,
291                                          "StubRoutines generation final stubs",
292                                          "StubRoutines (final stubs)",
293                                          "_final_stubs_code_size");
294   }
295 }
296 
297 void initial_stubs_init()      { StubRoutines::initialize_initial_stubs(); }
298 void continuation_stubs_init() { StubRoutines::initialize_continuation_stubs(); }
299 void final_stubs_init()        { StubRoutines::initialize_final_stubs(); }
300 
301 void compiler_stubs_init(bool in_compiler_thread) {
302   if (in_compiler_thread && DelayCompilerStubsGeneration) {
303     // Temporarily revert state of stubs generation because
304     // it is called after final_stubs_init() finished
305     // during compiler runtime initialization.
306     // It is fine because these stubs are only used by
307     // compiled code and compiler is not running yet.
308     StubCodeDesc::unfreeze();
309     StubRoutines::initialize_compiler_stubs();
310     StubCodeDesc::freeze();
311   } else if (!in_compiler_thread && !DelayCompilerStubsGeneration) {
312     StubRoutines::initialize_compiler_stubs();
313   }
314 }
315 
316 //
317 // Default versions of arraycopy functions
318 //
319 
320 JRT_LEAF(void, StubRoutines::jbyte_copy(jbyte* src, jbyte* dest, size_t count))
321 #ifndef PRODUCT
322   SharedRuntime::_jbyte_array_copy_ctr++;      // Slow-path byte array copy
323 #endif // !PRODUCT
324   Copy::conjoint_jbytes_atomic(src, dest, count);
325 JRT_END
326 
327 JRT_LEAF(void, StubRoutines::jshort_copy(jshort* src, jshort* dest, size_t count))
328 #ifndef PRODUCT
329   SharedRuntime::_jshort_array_copy_ctr++;     // Slow-path short/char array copy
330 #endif // !PRODUCT
331   Copy::conjoint_jshorts_atomic(src, dest, count);
332 JRT_END
333 
334 JRT_LEAF(void, StubRoutines::jint_copy(jint* src, jint* dest, size_t count))
335 #ifndef PRODUCT
336   SharedRuntime::_jint_array_copy_ctr++;       // Slow-path int/float array copy
337 #endif // !PRODUCT
338   Copy::conjoint_jints_atomic(src, dest, count);
339 JRT_END
340 
341 JRT_LEAF(void, StubRoutines::jlong_copy(jlong* src, jlong* dest, size_t count))
342 #ifndef PRODUCT
343   SharedRuntime::_jlong_array_copy_ctr++;      // Slow-path long/double array copy
344 #endif // !PRODUCT
345   Copy::conjoint_jlongs_atomic(src, dest, count);
346 JRT_END
347 
348 JRT_LEAF(void, StubRoutines::oop_copy(oop* src, oop* dest, size_t count))
349 #ifndef PRODUCT
350   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
351 #endif // !PRODUCT
352   assert(count != 0, "count should be non-zero");
353   ArrayAccess<>::oop_arraycopy_raw((HeapWord*)src, (HeapWord*)dest, count);
354 JRT_END
355 
356 JRT_LEAF(void, StubRoutines::oop_copy_uninit(oop* src, oop* dest, size_t count))
357 #ifndef PRODUCT
358   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
359 #endif // !PRODUCT
360   assert(count != 0, "count should be non-zero");
361   ArrayAccess<IS_DEST_UNINITIALIZED>::oop_arraycopy_raw((HeapWord*)src, (HeapWord*)dest, count);
362 JRT_END
363 
364 JRT_LEAF(void, StubRoutines::arrayof_jbyte_copy(HeapWord* src, HeapWord* dest, size_t count))
365 #ifndef PRODUCT
366   SharedRuntime::_jbyte_array_copy_ctr++;      // Slow-path byte array copy
367 #endif // !PRODUCT
368   Copy::arrayof_conjoint_jbytes(src, dest, count);
369 JRT_END
370 
371 JRT_LEAF(void, StubRoutines::arrayof_jshort_copy(HeapWord* src, HeapWord* dest, size_t count))
372 #ifndef PRODUCT
373   SharedRuntime::_jshort_array_copy_ctr++;     // Slow-path short/char array copy
374 #endif // !PRODUCT
375   Copy::arrayof_conjoint_jshorts(src, dest, count);
376 JRT_END
377 
378 JRT_LEAF(void, StubRoutines::arrayof_jint_copy(HeapWord* src, HeapWord* dest, size_t count))
379 #ifndef PRODUCT
380   SharedRuntime::_jint_array_copy_ctr++;       // Slow-path int/float array copy
381 #endif // !PRODUCT
382   Copy::arrayof_conjoint_jints(src, dest, count);
383 JRT_END
384 
385 JRT_LEAF(void, StubRoutines::arrayof_jlong_copy(HeapWord* src, HeapWord* dest, size_t count))
386 #ifndef PRODUCT
387   SharedRuntime::_jlong_array_copy_ctr++;       // Slow-path int/float array copy
388 #endif // !PRODUCT
389   Copy::arrayof_conjoint_jlongs(src, dest, count);
390 JRT_END
391 
392 JRT_LEAF(void, StubRoutines::arrayof_oop_copy(HeapWord* src, HeapWord* dest, size_t count))
393 #ifndef PRODUCT
394   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
395 #endif // !PRODUCT
396   assert(count != 0, "count should be non-zero");
397   ArrayAccess<ARRAYCOPY_ARRAYOF>::oop_arraycopy_raw(src, dest, count);
398 JRT_END
399 
400 JRT_LEAF(void, StubRoutines::arrayof_oop_copy_uninit(HeapWord* src, HeapWord* dest, size_t count))
401 #ifndef PRODUCT
402   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
403 #endif // !PRODUCT
404   assert(count != 0, "count should be non-zero");
405   ArrayAccess<ARRAYCOPY_ARRAYOF | IS_DEST_UNINITIALIZED>::oop_arraycopy_raw(src, dest, count);
406 JRT_END
407 
408 address StubRoutines::select_fill_function(BasicType t, bool aligned, const char* &name) {
409 #define RETURN_STUB(xxx_fill) { \
410   name = #xxx_fill; \
411   return StubRoutines::xxx_fill(); }
412 
413   switch (t) {
414   case T_BYTE:
415   case T_BOOLEAN:
416     if (!aligned) RETURN_STUB(jbyte_fill);
417     RETURN_STUB(arrayof_jbyte_fill);
418   case T_CHAR:
419   case T_SHORT:
420     if (!aligned) RETURN_STUB(jshort_fill);
421     RETURN_STUB(arrayof_jshort_fill);
422   case T_INT:
423   case T_FLOAT:
424     if (!aligned) RETURN_STUB(jint_fill);
425     RETURN_STUB(arrayof_jint_fill);
426   case T_DOUBLE:
427   case T_LONG:
428   case T_ARRAY:
429   case T_OBJECT:
430   case T_NARROWOOP:
431   case T_NARROWKLASS:
432   case T_ADDRESS:
433   case T_VOID:
434     // Currently unsupported
435     return nullptr;
436 
437   default:
438     ShouldNotReachHere();
439     return nullptr;
440   }
441 
442 #undef RETURN_STUB
443 }
444 
445 // constants for computing the copy function
446 enum {
447   COPYFUNC_UNALIGNED = 0,
448   COPYFUNC_ALIGNED = 1,                 // src, dest aligned to HeapWordSize
449   COPYFUNC_CONJOINT = 0,
450   COPYFUNC_DISJOINT = 2                 // src != dest, or transfer can descend
451 };
452 
453 // Note:  The condition "disjoint" applies also for overlapping copies
454 // where an descending copy is permitted (i.e., dest_offset <= src_offset).
455 address
456 StubRoutines::select_arraycopy_function(BasicType t, bool aligned, bool disjoint, const char* &name, bool dest_uninitialized) {
457   int selector =
458     (aligned  ? COPYFUNC_ALIGNED  : COPYFUNC_UNALIGNED) +
459     (disjoint ? COPYFUNC_DISJOINT : COPYFUNC_CONJOINT);
460 
461 #define RETURN_STUB(xxx_arraycopy) { \
462   name = #xxx_arraycopy; \
463   return StubRoutines::xxx_arraycopy(); }
464 
465 #define RETURN_STUB_PARM(xxx_arraycopy, parm) { \
466   name = parm ? #xxx_arraycopy "_uninit": #xxx_arraycopy; \
467   return StubRoutines::xxx_arraycopy(parm); }
468 
469   switch (t) {
470   case T_BYTE:
471   case T_BOOLEAN:
472     switch (selector) {
473     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jbyte_arraycopy);
474     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jbyte_arraycopy);
475     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jbyte_disjoint_arraycopy);
476     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jbyte_disjoint_arraycopy);
477     }
478   case T_CHAR:
479   case T_SHORT:
480     switch (selector) {
481     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jshort_arraycopy);
482     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jshort_arraycopy);
483     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jshort_disjoint_arraycopy);
484     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jshort_disjoint_arraycopy);
485     }
486   case T_INT:
487   case T_FLOAT:
488     switch (selector) {
489     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jint_arraycopy);
490     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jint_arraycopy);
491     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jint_disjoint_arraycopy);
492     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jint_disjoint_arraycopy);
493     }
494   case T_DOUBLE:
495   case T_LONG:
496     switch (selector) {
497     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jlong_arraycopy);
498     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jlong_arraycopy);
499     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB(jlong_disjoint_arraycopy);
500     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB(arrayof_jlong_disjoint_arraycopy);
501     }
502   case T_ARRAY:
503   case T_OBJECT:
504     switch (selector) {
505     case COPYFUNC_CONJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB_PARM(oop_arraycopy, dest_uninitialized);
506     case COPYFUNC_CONJOINT | COPYFUNC_ALIGNED:    RETURN_STUB_PARM(arrayof_oop_arraycopy, dest_uninitialized);
507     case COPYFUNC_DISJOINT | COPYFUNC_UNALIGNED:  RETURN_STUB_PARM(oop_disjoint_arraycopy, dest_uninitialized);
508     case COPYFUNC_DISJOINT | COPYFUNC_ALIGNED:    RETURN_STUB_PARM(arrayof_oop_disjoint_arraycopy, dest_uninitialized);
509     }
510   default:
511     ShouldNotReachHere();
512     return nullptr;
513   }
514 
515 #undef RETURN_STUB
516 #undef RETURN_STUB_PARM
517 }
518 
519 UnsafeCopyMemoryMark::UnsafeCopyMemoryMark(StubCodeGenerator* cgen, bool add_entry, bool continue_at_scope_end, address error_exit_pc) {
520   _cgen = cgen;
521   _ucm_entry = nullptr;
522   if (add_entry) {
523     address err_exit_pc = nullptr;
524     if (!continue_at_scope_end) {
525       err_exit_pc = error_exit_pc != nullptr ? error_exit_pc : UnsafeCopyMemory::common_exit_stub_pc();
526     }
527     assert(err_exit_pc != nullptr || continue_at_scope_end, "error exit not set");
528     _ucm_entry = UnsafeCopyMemory::add_to_table(_cgen->assembler()->pc(), nullptr, err_exit_pc);
529   }
530 }
531 
532 UnsafeCopyMemoryMark::~UnsafeCopyMemoryMark() {
533   if (_ucm_entry != nullptr) {
534     _ucm_entry->set_end_pc(_cgen->assembler()->pc());
535     if (_ucm_entry->error_exit_pc() == nullptr) {
536       _ucm_entry->set_error_exit_pc(_cgen->assembler()->pc());
537     }
538   }
539 }