1 /*
  2  * Copyright (c) 2017, 2026, 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 "cds/archiveUtils.hpp"
 26 #include "cds/cdsConfig.hpp"
 27 #include "classfile/vmSymbols.hpp"
 28 #include "code/codeCache.hpp"
 29 #include "gc/shared/barrierSet.hpp"
 30 #include "gc/shared/collectedHeap.inline.hpp"
 31 #include "gc/shared/gcLocker.inline.hpp"
 32 #include "interpreter/interpreter.hpp"
 33 #include "logging/log.hpp"
 34 #include "memory/metadataFactory.hpp"
 35 #include "memory/metaspaceClosure.hpp"
 36 #include "oops/access.hpp"
 37 #include "oops/arrayKlass.hpp"
 38 #include "oops/compressedOops.inline.hpp"
 39 #include "oops/fieldStreams.inline.hpp"
 40 #include "oops/flatArrayKlass.hpp"
 41 #include "oops/inlineKlass.inline.hpp"
 42 #include "oops/instanceKlass.inline.hpp"
 43 #include "oops/method.hpp"
 44 #include "oops/objArrayKlass.hpp"
 45 #include "oops/oop.inline.hpp"
 46 #include "oops/refArrayKlass.hpp"
 47 #include "runtime/fieldDescriptor.inline.hpp"
 48 #include "runtime/handles.inline.hpp"
 49 #include "runtime/registerMap.hpp"
 50 #include "runtime/safepointVerifiers.hpp"
 51 #include "runtime/sharedRuntime.hpp"
 52 #include "runtime/signature.hpp"
 53 #include "runtime/thread.inline.hpp"
 54 #include "utilities/copy.hpp"
 55 #include "utilities/stringUtils.hpp"
 56 
 57 InlineKlass::Members::Members()
 58   : _extended_sig(nullptr),
 59     _return_regs(nullptr),
 60     _pack_handler(nullptr),
 61     _pack_handler_jobject(nullptr),
 62     _unpack_handler(nullptr),
 63     _null_reset_value_offset(0),
 64     _payload_offset(-1),
 65     _payload_size_in_bytes(-1),
 66     _payload_alignment(-1),
 67     _non_atomic_size_in_bytes(-1),
 68     _non_atomic_alignment(-1),
 69     _atomic_size_in_bytes(-1),
 70     _nullable_size_in_bytes(-1),
 71     _null_marker_offset(-1) {
 72 }
 73 
 74 InlineKlass::InlineKlass() {
 75   assert(CDSConfig::is_dumping_archive() || UseSharedSpaces, "only for CDS");
 76 }
 77 
 78 // Constructor
 79 InlineKlass::InlineKlass(const ClassFileParser& parser)
 80     : InstanceKlass(parser, InlineKlass::Kind, markWord::inline_type_prototype()) {
 81   assert(is_inline_klass(), "sanity");
 82   assert(prototype_header().is_inline_type(), "sanity");
 83 
 84   // Set up the offset to the members of this klass
 85   _adr_inline_klass_members = calculate_members_address();
 86 
 87   // Placement install the members
 88   new (_adr_inline_klass_members) Members();
 89 
 90   // Sanity check construction of the members
 91   assert(pack_handler() == nullptr, "pack handler not null");
 92 }
 93 
 94 address InlineKlass::calculate_members_address() const {
 95   // The members are placed after all other contents inherited from the InstanceKlass
 96   return end_of_instance_klass();
 97 }
 98 
 99 oop InlineKlass::null_reset_value() {
100   assert(is_initialized() || is_being_initialized() || is_in_error_state(), "null reset value is set at the beginning of initialization");
101   oop val = java_mirror()->obj_field_acquire(null_reset_value_offset());
102   assert(val != nullptr, "Sanity check");
103   return val;
104 }
105 
106 void InlineKlass::set_null_reset_value(oop val) {
107   assert(val != nullptr, "Sanity check");
108   assert(oopDesc::is_oop(val), "Sanity check");
109   assert(val->is_inline_type(), "Sanity check");
110   assert(val->klass() == this, "sanity check");
111   java_mirror()->obj_field_put(null_reset_value_offset(), val);
112 }
113 
114 instanceOop InlineKlass::allocate_instance(TRAPS) {
115   instanceOop oop = InstanceKlass::allocate_instance(CHECK_NULL);
116   assert(oop->mark().is_inline_type(), "Expected inline type");
117   return oop;
118 }
119 
120 int InlineKlass::nonstatic_oop_count() {
121   int oops = 0;
122   int map_count = nonstatic_oop_map_count();
123   OopMapBlock* block = start_of_nonstatic_oop_maps();
124   OopMapBlock* end = block + map_count;
125   while (block != end) {
126     oops += block->count();
127     block++;
128   }
129   return oops;
130 }
131 
132 int InlineKlass::layout_size_in_bytes(LayoutKind kind) const {
133   switch(kind) {
134     case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
135       assert(has_non_atomic_layout(), "Layout not available");
136       return non_atomic_size_in_bytes();
137       break;
138     case LayoutKind::NULL_FREE_ATOMIC_FLAT:
139       assert(has_atomic_layout(), "Layout not available");
140       return atomic_size_in_bytes();
141       break;
142     case LayoutKind::NULLABLE_ATOMIC_FLAT:
143       assert(has_nullable_atomic_layout(), "Layout not available");
144       return nullable_atomic_size_in_bytes();
145       break;
146     case LayoutKind::BUFFERED:
147       return payload_size_in_bytes();
148       break;
149     default:
150       ShouldNotReachHere();
151   }
152 }
153 
154 int InlineKlass::layout_alignment(LayoutKind kind) const {
155   switch(kind) {
156     case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
157       assert(has_non_atomic_layout(), "Layout not available");
158       return non_atomic_alignment();
159       break;
160     case LayoutKind::NULL_FREE_ATOMIC_FLAT:
161       assert(has_atomic_layout(), "Layout not available");
162       return atomic_size_in_bytes();
163       break;
164     case LayoutKind::NULLABLE_ATOMIC_FLAT:
165       assert(has_nullable_atomic_layout(), "Layout not available");
166       return nullable_atomic_size_in_bytes();
167       break;
168     case LayoutKind::BUFFERED:
169       return payload_alignment();
170       break;
171     default:
172       ShouldNotReachHere();
173   }
174 }
175 
176 bool InlineKlass::is_layout_supported(LayoutKind lk) {
177   switch(lk) {
178     case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT:
179       return has_non_atomic_layout();
180       break;
181     case LayoutKind::NULL_FREE_ATOMIC_FLAT:
182       return has_atomic_layout();
183       break;
184     case LayoutKind::NULLABLE_ATOMIC_FLAT:
185       return has_nullable_atomic_layout();
186       break;
187     case LayoutKind::BUFFERED:
188       return true;
189       break;
190     default:
191       ShouldNotReachHere();
192   }
193 }
194 
195 void InlineKlass::copy_payload_to_addr(void* src, void* dst, LayoutKind lk, bool dest_is_initialized) {
196   assert(is_layout_supported(lk), "Unsupported layout");
197   assert(lk != LayoutKind::REFERENCE && lk != LayoutKind::UNKNOWN, "Sanity check");
198   switch(lk) {
199     case LayoutKind::NULLABLE_ATOMIC_FLAT: {
200       if (is_payload_marked_as_null((address)src)) {
201         // copy null_reset value to dest
202         if (dest_is_initialized) {
203           HeapAccess<>::value_copy(payload_addr(null_reset_value()), dst, this, lk);
204         } else {
205           HeapAccess<IS_DEST_UNINITIALIZED>::value_copy(payload_addr(null_reset_value()), dst, this, lk);
206         }
207       } else {
208         // Copy has to be performed, even if this is an empty value, because of the null marker
209         if (dest_is_initialized) {
210           HeapAccess<>::value_copy(src, dst, this, lk);
211         } else {
212           HeapAccess<IS_DEST_UNINITIALIZED>::value_copy(src, dst, this, lk);
213         }
214       }
215     }
216     break;
217     case LayoutKind::BUFFERED:
218     case LayoutKind::NULL_FREE_ATOMIC_FLAT:
219     case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT: {
220       if (is_empty_inline_type()) return; // nothing to do
221       if (dest_is_initialized) {
222         HeapAccess<>::value_copy(src, dst, this, lk);
223       } else {
224         HeapAccess<IS_DEST_UNINITIALIZED>::value_copy(src, dst, this, lk);
225       }
226     }
227     break;
228     default:
229       ShouldNotReachHere();
230   }
231 }
232 
233 oop InlineKlass::read_payload_from_addr(const oop src, size_t offset, LayoutKind lk, TRAPS) {
234   assert(src != nullptr, "Must be");
235   assert(is_layout_supported(lk), "Unsupported layout");
236   switch(lk) {
237     case LayoutKind::NULLABLE_ATOMIC_FLAT: {
238       if (is_payload_marked_as_null(cast_from_oop<address>(src) + offset)) {
239         return nullptr;
240       }
241     } // Fallthrough
242     case LayoutKind::BUFFERED:
243     case LayoutKind::NULL_FREE_ATOMIC_FLAT:
244     case LayoutKind::NULL_FREE_NON_ATOMIC_FLAT: {
245       Handle obj_h(THREAD, src);
246       oop res = allocate_instance(CHECK_NULL);
247       copy_payload_to_addr((void*)(cast_from_oop<address>(obj_h()) + offset), payload_addr(res), lk, false);
248 
249       // After copying, re-check if the payload is now marked as null. Another
250       // thread could have marked the src object as null after the initial check
251       // but before the copy operation, causing the null-marker to be marked in
252       // the destination. In this case, discard the allocated object and
253       // return nullptr.
254       if (LayoutKindHelper::is_nullable_flat(lk)) {
255         if (is_payload_marked_as_null(payload_addr(res))) {
256           return nullptr;
257         }
258       }
259 
260       return res;
261     }
262     break;
263     default:
264       ShouldNotReachHere();
265   }
266 }
267 
268 void InlineKlass::write_value_to_addr(oop src, void* dst, LayoutKind lk, TRAPS) {
269   void* src_addr = nullptr;
270   if (src == nullptr) {
271     if (!LayoutKindHelper::is_nullable_flat(lk)) {
272       THROW_MSG(vmSymbols::java_lang_NullPointerException(), "Value is null");
273     }
274     // Writing null to a nullable flat field/element is usually done by writing
275     // the whole pre-allocated null_reset_value at the payload address to ensure
276     // that the null marker and all potential oops are reset to "zeros".
277     // However, the null_reset_value is allocated during class initialization.
278     // If the current value of the field is null, it is possible that the class
279     // of the field has not been initialized yet and thus the null_reset_value
280     // might not be available yet.
281     // Writing null over an already null value should not trigger class initialization.
282     // The solution is to detect null being written over null cases and return immediately
283     // (writing null over null is a no-op from a field modification point of view)
284     if (is_payload_marked_as_null((address)dst)) return;
285     src_addr = payload_addr(null_reset_value());
286   } else {
287     src_addr = payload_addr(src);
288     if (LayoutKindHelper::is_nullable_flat(lk)) {
289       mark_payload_as_non_null((address)src_addr);
290     }
291   }
292   copy_payload_to_addr(src_addr, dst, lk, true /* dest_is_initialized */);
293 }
294 
295 // Arrays of...
296 
297 bool InlineKlass::maybe_flat_in_array() {
298   if (!UseArrayFlattening) {
299     return false;
300   }
301   // Too many embedded oops
302   if ((FlatArrayElementMaxOops >= 0) && (nonstatic_oop_count() > FlatArrayElementMaxOops)) {
303     return false;
304   }
305   // No flat layout?
306   if (!has_nullable_atomic_layout() && !has_atomic_layout() && !has_non_atomic_layout()) {
307     return false;
308   }
309   return true;
310 }
311 
312 bool InlineKlass::is_always_flat_in_array() {
313   if (!UseArrayFlattening) {
314     return false;
315   }
316   // Too many embedded oops
317   if ((FlatArrayElementMaxOops >= 0) && (nonstatic_oop_count() > FlatArrayElementMaxOops)) {
318     return false;
319   }
320 
321   // An instance is always flat in an array if we have all layouts. Note that this could change in the future when the
322   // flattening policies are updated or if new APIs are added that allow the creation of reference arrays directly.
323   return has_nullable_atomic_layout() && has_atomic_layout() && has_non_atomic_layout();
324 }
325 
326 // Inline type arguments are not passed by reference, instead each
327 // field of the inline type is passed as an argument. This helper
328 // function collects the flat field (recursively)
329 // in a list. Included with the field's type is
330 // the offset of each field in the inline type: i2c and c2i adapters
331 // need that to load or store fields. Finally, the list of fields is
332 // sorted in order of increasing offsets: the adapters and the
333 // compiled code need to agree upon the order of fields.
334 //
335 // The list of basic types that is returned starts with a T_METADATA
336 // and ends with an extra T_VOID. T_METADATA/T_VOID pairs are used as
337 // delimiters. Every entry between the two is a field of the inline
338 // type. If there's an embedded inline type in the list, it also starts
339 // with a T_METADATA and ends with a T_VOID. This is so we can
340 // generate a unique fingerprint for the method's adapters and we can
341 // generate the list of basic types from the interpreter point of view
342 // (inline types passed as reference: iterate on the list until a
343 // T_METADATA, drop everything until and including the closing
344 // T_VOID) or the compiler point of view (each field of the inline
345 // types is an argument: drop all T_METADATA/T_VOID from the list).
346 //
347 // Value classes could also have fields in abstract super value classes.
348 // Use a HierarchicalFieldStream to get them as well.
349 int InlineKlass::collect_fields(GrowableArray<SigEntry>* sig, int base_off, int null_marker_offset) {
350   int count = 0;
351   SigEntry::add_entry(sig, T_METADATA, name(), base_off);
352   for (TopDownHierarchicalNonStaticFieldStreamBase fs(this); !fs.done(); fs.next()) {
353     assert(!fs.access_flags().is_static(), "TopDownHierarchicalNonStaticFieldStreamBase should not let static fields pass.");
354     int offset = base_off + fs.offset() - (base_off > 0 ? payload_offset() : 0);
355     InstanceKlass* field_holder = fs.field_descriptor().field_holder();
356     // TODO 8284443 Use different heuristic to decide what should be scalarized in the calling convention
357     if (fs.is_flat()) {
358       // Resolve klass of flat field and recursively collect fields
359       int field_null_marker_offset = -1;
360       if (!fs.is_null_free_inline_type()) {
361         field_null_marker_offset = base_off + fs.null_marker_offset() - (base_off > 0 ? payload_offset() : 0);
362       }
363       Klass* vk = field_holder->get_inline_type_field_klass(fs.index());
364       count += InlineKlass::cast(vk)->collect_fields(sig, offset, field_null_marker_offset);
365     } else {
366       BasicType bt = Signature::basic_type(fs.signature());
367       SigEntry::add_entry(sig, bt,  fs.name(), offset);
368       count += type2size[bt];
369     }
370   }
371   int offset = base_off + size_helper()*HeapWordSize - (base_off > 0 ? payload_offset() : 0);
372   // Null markers are no real fields, add them manually at the end (C2 relies on this) of the flat fields
373   if (null_marker_offset != -1) {
374     SigEntry::add_null_marker(sig, name(), null_marker_offset);
375     count++;
376   }
377   SigEntry::add_entry(sig, T_VOID, name(), offset);
378   assert(sig->at(0)._bt == T_METADATA && sig->at(sig->length()-1)._bt == T_VOID, "broken structure");
379   return count;
380 }
381 
382 void InlineKlass::initialize_calling_convention(TRAPS) {
383   // Because the pack and unpack handler addresses need to be loadable from generated code,
384   // they are stored at a fixed offset in the klass metadata. Since inline type klasses do
385   // not have a vtable, the vtable offset is used to store these addresses.
386   if (InlineTypeReturnedAsFields || InlineTypePassFieldsAsArgs) {
387     ResourceMark rm;
388     GrowableArray<SigEntry> sig_vk;
389     int nb_fields = collect_fields(&sig_vk);
390     if (*PrintInlineKlassFields != '\0') {
391       const char* class_name_str = _name->as_C_string();
392       if (StringUtils::class_list_match(PrintInlineKlassFields, class_name_str)) {
393         ttyLocker ttyl;
394         tty->print_cr("Fields of InlineKlass: %s", class_name_str);
395         for (const SigEntry& entry : sig_vk) {
396           tty->print("  %s: %s+%d", entry._name->as_C_string(), type2name(entry._bt), entry._offset);
397           if (entry._null_marker) {
398             tty->print(" (null marker)");
399           }
400           tty->print_cr("");
401         }
402       }
403     }
404     Array<SigEntry>* extended_sig = MetadataFactory::new_array<SigEntry>(class_loader_data(), sig_vk.length(), CHECK);
405     set_extended_sig(extended_sig);
406     for (int i = 0; i < sig_vk.length(); i++) {
407       extended_sig->at_put(i, sig_vk.at(i));
408     }
409     if (can_be_returned_as_fields(/* init= */ true)) {
410       nb_fields++;
411       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, nb_fields);
412       sig_bt[0] = T_METADATA;
413       SigEntry::fill_sig_bt(&sig_vk, sig_bt+1);
414       VMRegPair* regs = NEW_RESOURCE_ARRAY(VMRegPair, nb_fields);
415       int total = SharedRuntime::java_return_convention(sig_bt, regs, nb_fields);
416 
417       if (total > 0) {
418         Array<VMRegPair>* return_regs = MetadataFactory::new_array<VMRegPair>(class_loader_data(), nb_fields, CHECK);
419         set_return_regs(return_regs);
420         for (int i = 0; i < nb_fields; i++) {
421           return_regs->at_put(i, regs[i]);
422         }
423 
424         BufferedInlineTypeBlob* buffered_blob = SharedRuntime::generate_buffered_inline_type_adapter(this);
425         if (buffered_blob == nullptr) {
426           THROW_MSG(vmSymbols::java_lang_OutOfMemoryError(), "Out of space in CodeCache for adapters");
427         }
428         set_pack_handler(buffered_blob->pack_fields());
429         set_pack_handler_jobject(buffered_blob->pack_fields_jobject());
430         set_unpack_handler(buffered_blob->unpack_fields());
431         assert(CodeCache::find_blob(pack_handler()) == buffered_blob, "lost track of blob");
432         assert(can_be_returned_as_fields(), "sanity");
433       }
434     }
435     if (!can_be_returned_as_fields() && !can_be_passed_as_fields()) {
436       MetadataFactory::free_array<SigEntry>(class_loader_data(), extended_sig);
437       assert(return_regs() == nullptr, "sanity");
438     }
439   }
440 }
441 
442 void InlineKlass::deallocate_contents(ClassLoaderData* loader_data) {
443   if (extended_sig() != nullptr) {
444     MetadataFactory::free_array<SigEntry>(loader_data, members()._extended_sig);
445     set_extended_sig(nullptr);
446   }
447   if (return_regs() != nullptr) {
448     MetadataFactory::free_array<VMRegPair>(loader_data, members()._return_regs);
449     set_return_regs(nullptr);
450   }
451   cleanup_blobs();
452   InstanceKlass::deallocate_contents(loader_data);
453 }
454 
455 void InlineKlass::cleanup(InlineKlass* ik) {
456   ik->cleanup_blobs();
457 }
458 
459 void InlineKlass::cleanup_blobs() {
460   if (pack_handler() != nullptr) {
461     CodeBlob* buffered_blob = CodeCache::find_blob(pack_handler());
462     assert(buffered_blob->is_buffered_inline_type_blob(), "bad blob type");
463     BufferBlob::free((BufferBlob*)buffered_blob);
464     set_pack_handler(nullptr);
465     set_pack_handler_jobject(nullptr);
466     set_unpack_handler(nullptr);
467   }
468 }
469 
470 // Can this inline type be passed as multiple values?
471 bool InlineKlass::can_be_passed_as_fields() const {
472   return InlineTypePassFieldsAsArgs;
473 }
474 
475 // Can this inline type be returned as multiple values?
476 bool InlineKlass::can_be_returned_as_fields(bool init) const {
477   return InlineTypeReturnedAsFields && (init || return_regs() != nullptr);
478 }
479 
480 // Create handles for all oop fields returned in registers that are going to be live across a safepoint
481 void InlineKlass::save_oop_fields(const RegisterMap& reg_map, GrowableArray<Handle>& handles) const {
482   Thread* thread = Thread::current();
483   const Array<SigEntry>* sig_vk = extended_sig();
484   const Array<VMRegPair>* regs = return_regs();
485   int j = 1;
486 
487   for (int i = 0; i < sig_vk->length(); i++) {
488     BasicType bt = sig_vk->at(i)._bt;
489     if (bt == T_OBJECT || bt == T_ARRAY) {
490       VMRegPair pair = regs->at(j);
491       address loc = reg_map.location(pair.first(), nullptr);
492       oop o = *(oop*)loc;
493       assert(oopDesc::is_oop_or_null(o), "Bad oop value: " PTR_FORMAT, p2i(o));
494       handles.push(Handle(thread, o));
495     }
496     if (bt == T_METADATA) {
497       continue;
498     }
499     if (bt == T_VOID &&
500         sig_vk->at(i-1)._bt != T_LONG &&
501         sig_vk->at(i-1)._bt != T_DOUBLE) {
502       continue;
503     }
504     j++;
505   }
506   assert(j == regs->length(), "missed a field?");
507 }
508 
509 // Update oop fields in registers from handles after a safepoint
510 void InlineKlass::restore_oop_results(RegisterMap& reg_map, GrowableArray<Handle>& handles) const {
511   assert(InlineTypeReturnedAsFields, "Inline types should never be returned as fields");
512   const Array<SigEntry>* sig_vk = extended_sig();
513   const Array<VMRegPair>* regs = return_regs();
514   assert(regs != nullptr, "inconsistent");
515 
516   int j = 1;
517   int k = 0;
518   for (int i = 0; i < sig_vk->length(); i++) {
519     BasicType bt = sig_vk->at(i)._bt;
520     if (bt == T_OBJECT || bt == T_ARRAY) {
521       VMRegPair pair = regs->at(j);
522       address loc = reg_map.location(pair.first(), nullptr);
523       *(oop*)loc = handles.at(k++)();
524     }
525     if (bt == T_METADATA) {
526       continue;
527     }
528     if (bt == T_VOID &&
529         sig_vk->at(i-1)._bt != T_LONG &&
530         sig_vk->at(i-1)._bt != T_DOUBLE) {
531       continue;
532     }
533     j++;
534   }
535   assert(k == handles.length(), "missed a handle?");
536   assert(j == regs->length(), "missed a field?");
537 }
538 
539 // Fields are in registers. Create an instance of the inline type and
540 // initialize it with the values of the fields.
541 oop InlineKlass::realloc_result(const RegisterMap& reg_map, const GrowableArray<Handle>& handles, TRAPS) {
542   oop new_vt = allocate_instance(CHECK_NULL);
543   const Array<SigEntry>* sig_vk = extended_sig();
544   const Array<VMRegPair>* regs = return_regs();
545 
546   int j = 1;
547   int k = 0;
548   for (int i = 0; i < sig_vk->length(); i++) {
549     BasicType bt = sig_vk->at(i)._bt;
550     if (bt == T_METADATA) {
551       continue;
552     }
553     if (bt == T_VOID) {
554       if (sig_vk->at(i-1)._bt == T_LONG ||
555           sig_vk->at(i-1)._bt == T_DOUBLE) {
556         j++;
557       }
558       continue;
559     }
560     int off = sig_vk->at(i)._offset;
561     assert(off > 0, "offset in object should be positive");
562     VMRegPair pair = regs->at(j);
563     address loc = reg_map.location(pair.first(), nullptr);
564     switch(bt) {
565     case T_BOOLEAN: {
566       new_vt->bool_field_put(off, *(jboolean*)loc);
567       break;
568     }
569     case T_CHAR: {
570       new_vt->char_field_put(off, *(jchar*)loc);
571       break;
572     }
573     case T_BYTE: {
574       new_vt->byte_field_put(off, *(jbyte*)loc);
575       break;
576     }
577     case T_SHORT: {
578       new_vt->short_field_put(off, *(jshort*)loc);
579       break;
580     }
581     case T_INT: {
582       new_vt->int_field_put(off, *(jint*)loc);
583       break;
584     }
585     case T_LONG: {
586 #ifdef _LP64
587       new_vt->double_field_put(off,  *(jdouble*)loc);
588 #else
589       Unimplemented();
590 #endif
591       break;
592     }
593     case T_OBJECT:
594     case T_ARRAY: {
595       Handle handle = handles.at(k++);
596       new_vt->obj_field_put(off, handle());
597       break;
598     }
599     case T_FLOAT: {
600       new_vt->float_field_put(off,  *(jfloat*)loc);
601       break;
602     }
603     case T_DOUBLE: {
604       new_vt->double_field_put(off, *(jdouble*)loc);
605       break;
606     }
607     default:
608       ShouldNotReachHere();
609     }
610     *(intptr_t*)loc = 0xDEAD;
611     j++;
612   }
613   assert(j == regs->length(), "missed a field?");
614   assert(k == handles.length(), "missed an oop?");
615   return new_vt;
616 }
617 
618 // Check if we return an inline type in scalarized form, i.e. check if either
619 // - The return value is a tagged InlineKlass pointer, or
620 // - The return value is an inline type oop that is also returned in scalarized form
621 InlineKlass* InlineKlass::returned_inline_klass(const RegisterMap& map, bool* return_oop, Method* method) {
622   BasicType bt = T_METADATA;
623   VMRegPair pair;
624   int nb = SharedRuntime::java_return_convention(&bt, &pair, 1);
625   assert(nb == 1, "broken");
626 
627   address loc = map.location(pair.first(), nullptr);
628   intptr_t ptr = *(intptr_t*)loc;
629   if (is_set_nth_bit(ptr, 0)) {
630     // Return value is tagged, must be an InlineKlass pointer
631     clear_nth_bit(ptr, 0);
632     assert(Metaspace::contains((void*)ptr), "should be klass");
633     InlineKlass* vk = (InlineKlass*)ptr;
634     assert(vk->can_be_returned_as_fields(), "must be able to return as fields");
635     if (return_oop != nullptr) {
636       // Not returning an oop
637       *return_oop = false;
638     }
639     return vk;
640   }
641   // Return value is not tagged, must be a valid oop
642   oop o = cast_to_oop(ptr);
643   assert(oopDesc::is_oop_or_null(o), "Bad oop return: " PTR_FORMAT, ptr);
644   if (return_oop != nullptr && o != nullptr && o->is_inline_type()) {
645     // Check if inline type is also returned in scalarized form
646     InlineKlass* vk_val = InlineKlass::cast(o->klass());
647     InlineKlass* vk_sig = method->returns_inline_type();
648     if (vk_val->can_be_returned_as_fields() && vk_sig != nullptr) {
649       assert(vk_val == vk_sig, "Unexpected return value");
650       return vk_val;
651     }
652   }
653   return nullptr;
654 }
655 
656 // CDS support
657 #if INCLUDE_CDS
658 
659 void InlineKlass::remove_unshareable_info() {
660   InstanceKlass::remove_unshareable_info();
661 
662   // update it to point to the "buffered" copy of this class.
663   _adr_inline_klass_members = calculate_members_address();
664   ArchivePtrMarker::mark_pointer(&_adr_inline_klass_members);
665 
666   set_extended_sig(nullptr);
667   set_return_regs(nullptr);
668   set_pack_handler(nullptr);
669   set_pack_handler_jobject(nullptr);
670   set_unpack_handler(nullptr);
671 
672   assert(pack_handler() == nullptr, "pack handler not null");
673 }
674 
675 #endif // CDS
676 
677 // Verification
678 
679 void InlineKlass::verify_on(outputStream* st) {
680   InstanceKlass::verify_on(st);
681   guarantee(prototype_header().is_inline_type(), "Prototype header is not inline type");
682 }
683 
684 void InlineKlass::oop_verify_on(oop obj, outputStream* st) {
685   InstanceKlass::oop_verify_on(obj, st);
686   guarantee(obj->mark().is_inline_type(), "Header is not inline type");
687 }