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src/hotspot/share/gc/shenandoah/shenandoahNMethod.cpp

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 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  *
 24  */
 25 
 26 
 27 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
 28 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 29 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
 30 #include "memory/resourceArea.hpp"
 31 #include "runtime/continuation.hpp"
 32 #include "runtime/safepointVerifiers.hpp"
 33 
 34 ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop*>& oops, bool non_immediate_oops) :
 35   _nm(nm), _oops(nullptr), _oops_count(0), _unregistered(false), _lock(), _ic_lock() {
 36 
 37   if (!oops.is_empty()) {
 38     _oops_count = oops.length();
 39     _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC);
 40     for (int c = 0; c < _oops_count; c++) {
 41       _oops[c] = oops.at(c);
 42     }
 43   }
 44   _has_non_immed_oops = non_immediate_oops;
 45 
 46   assert_same_oops();








 47 }
 48 
 49 ShenandoahNMethod::~ShenandoahNMethod() {
 50   if (_oops != nullptr) {
 51     FREE_C_HEAP_ARRAY(oop*, _oops);
 52   }



 53 }
 54 
 55 void ShenandoahNMethod::update() {
 56   ResourceMark rm;
 57   bool non_immediate_oops = false;
 58   GrowableArray<oop*> oops;

 59 
 60   detect_reloc_oops(nm(), oops, non_immediate_oops);
 61   if (oops.length() != _oops_count) {
 62     if (_oops != nullptr) {
 63       FREE_C_HEAP_ARRAY(oop*, _oops);
 64       _oops = nullptr;
 65     }
 66 
 67     _oops_count = oops.length();
 68     if (_oops_count > 0) {
 69       _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC);
 70     }
 71   }
 72 
 73   for (int index = 0; index < _oops_count; index ++) {
 74     _oops[index] = oops.at(index);
 75   }
 76   _has_non_immed_oops = non_immediate_oops;
 77 
 78   assert_same_oops();
 79 }
 80 
 81 void ShenandoahNMethod::detect_reloc_oops(nmethod* nm, GrowableArray<oop*>& oops, bool& has_non_immed_oops) {
 82   has_non_immed_oops = false;
 83   // Find all oops relocations
 84   RelocIterator iter(nm);
 85   while (iter.next()) {
 86     if (iter.type() != relocInfo::oop_type) {
 87       // Not an oop
 88       continue;
 89     }
 90 
 91     oop_Relocation* r = iter.oop_reloc();
 92     if (!r->oop_is_immediate()) {
 93       // Non-immediate oop found
 94       has_non_immed_oops = true;
 95       continue;
 96     }






























 97 
 98     oop value = r->oop_value();
 99     if (value != nullptr) {
100       oop* addr = r->oop_addr();
101       shenandoah_assert_correct(addr, value);
102       shenandoah_assert_not_in_cset_except(addr, value, ShenandoahHeap::heap()->cancelled_gc());
103       shenandoah_assert_not_forwarded(addr, value);
104       // Non-null immediate oop found. null oops can safely be
105       // ignored since the method will be re-registered if they
106       // are later patched to be non-null.
107       oops.push(addr);
108     }
109   }
110 }
111 
112 ShenandoahNMethod* ShenandoahNMethod::for_nmethod(nmethod* nm) {
113   ResourceMark rm;
114   bool non_immediate_oops = false;
115   GrowableArray<oop*> oops;

116 
117   detect_reloc_oops(nm, oops, non_immediate_oops);
118   return new ShenandoahNMethod(nm, oops, non_immediate_oops);
119 }
120 
121 void ShenandoahNMethod::heal_nmethod(nmethod* nm) {
122   ShenandoahNMethod* data = gc_data(nm);
123   assert(data != nullptr, "Sanity");
124   assert(data->lock()->owned_by_self(), "Must hold the lock");
125 
126   ShenandoahHeap* const heap = ShenandoahHeap::heap();
127   if (heap->is_concurrent_weak_root_in_progress() ||
128       heap->is_concurrent_strong_root_in_progress()) {
129     ShenandoahEvacOOMScope evac_scope;
130     heal_nmethod_metadata(data);
131   } else if (heap->is_concurrent_mark_in_progress()) {
132     ShenandoahKeepAliveClosure cl;
133     data->oops_do(&cl);
134   } else {
135     // There is possibility that GC is cancelled when it arrives final mark.
136     // In this case, concurrent root phase is skipped and degenerated GC should be
137     // followed, where nmethods are disarmed.
138   }



























































139 }
140 
141 #ifdef ASSERT
142 void ShenandoahNMethod::assert_correct() {
143   ShenandoahHeap* heap = ShenandoahHeap::heap();
144   for (int c = 0; c < _oops_count; c++) {
145     oop *loc = _oops[c];
146     assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*");
147     oop o = RawAccess<>::oop_load(loc);
148     shenandoah_assert_correct_except(loc, o, o == nullptr || heap->is_full_gc_move_in_progress());
149   }
150 
151   oop* const begin = _nm->oops_begin();
152   oop* const end = _nm->oops_end();
153   for (oop* p = begin; p < end; p++) {
154     if (*p != Universe::non_oop_word()) {
155       oop o = RawAccess<>::oop_load(p);
156       shenandoah_assert_correct_except(p, o, o == nullptr || heap->is_full_gc_move_in_progress());
157     }
158   }

189     assert(oops->contains(_oops[index]), "Must contain this oop");
190   }
191 
192   for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) {
193     if (*p == Universe::non_oop_word()) continue;
194     count++;
195     assert(oops->contains(p), "Must contain this oop");
196   }
197 
198   if (oops->length() < count) {
199     stringStream debug_stream;
200     debug_stream.print_cr("detected locs: %d", oops->length());
201     for (int i = 0; i < oops->length(); i++) {
202       debug_stream.print_cr("-> " PTR_FORMAT, p2i(oops->at(i)));
203     }
204     debug_stream.print_cr("recorded oops: %d", _oops_count);
205     for (int i = 0; i < _oops_count; i++) {
206       debug_stream.print_cr("-> " PTR_FORMAT, p2i(_oops[i]));
207     }
208     GrowableArray<oop*> check;

209     bool non_immed;
210     detect_reloc_oops(nm(), check, non_immed);
211     debug_stream.print_cr("check oops: %d", check.length());
212     for (int i = 0; i < check.length(); i++) {
213       debug_stream.print_cr("-> " PTR_FORMAT, p2i(check.at(i)));
214     }
215     fatal("Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT "\n%s",
216           oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()), debug_stream.freeze());
217   }
218 }
219 #endif
220 
221 ShenandoahNMethodTable::ShenandoahNMethodTable() :
222   _heap(ShenandoahHeap::heap()),
223   _index(0),
224   _itr_cnt(0) {
225   _list = new ShenandoahNMethodList(minSize);
226 }
227 
228 ShenandoahNMethodTable::~ShenandoahNMethodTable() {
229   assert(_list != nullptr, "Sanity");
230   _list->release();
231 }
232 
233 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) {
234   assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
235   assert(_index >= 0 && _index <= _list->size(), "Sanity");
236 
237   ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
238 
239   if (data != nullptr) {
240     assert(contain(nm), "Must have been registered");
241     assert(nm == data->nm(), "Must be same nmethod");
242     // Prevent updating a nmethod while concurrent iteration is in progress.
243     wait_until_concurrent_iteration_done();
244     ShenandoahNMethodLocker data_locker(data->lock());
245     data->update();

246   } else {
247     // For a new nmethod, we can safely append it to the list, because
248     // concurrent iteration will not touch it.
249     data = ShenandoahNMethod::for_nmethod(nm);

250     assert(data != nullptr, "Sanity");
251     ShenandoahNMethod::attach_gc_data(nm, data);
252     ShenandoahLocker locker(&_lock);
253     log_register_nmethod(nm);
254     append(data);
255   }
256   // Disarm new nmethod
257   ShenandoahNMethod::disarm_nmethod(nm);
258 }
259 
260 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) {
261   assert_locked_or_safepoint(CodeCache_lock);
262 
263   ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
264   assert(data != nullptr, "Sanity");
265   log_unregister_nmethod(nm);
266   ShenandoahLocker locker(&_lock);
267   assert(contain(nm), "Must have been registered");
268 
269   int idx = index_of(nm);

 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  *
 24  */
 25 
 26 
 27 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
 28 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 29 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
 30 #include "memory/resourceArea.hpp"
 31 #include "runtime/continuation.hpp"
 32 #include "runtime/safepointVerifiers.hpp"
 33 
 34 ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop*>& oops, bool non_immediate_oops, GrowableArray<ShenandoahNMethodBarrier>& barriers) :
 35   _nm(nm), _oops(nullptr), _oops_count(0), _barriers(nullptr), _unregistered(false), _lock(), _ic_lock() {
 36 
 37   if (!oops.is_empty()) {
 38     _oops_count = oops.length();
 39     _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC);
 40     for (int c = 0; c < _oops_count; c++) {
 41       _oops[c] = oops.at(c);
 42     }
 43   }
 44   _has_non_immed_oops = non_immediate_oops;
 45 
 46   assert_same_oops();
 47 
 48   if (!barriers.is_empty()) {
 49     _barriers_count = barriers.length();
 50     _barriers = NEW_C_HEAP_ARRAY(ShenandoahNMethodBarrier, _barriers_count, mtGC);
 51     for (int c = 0; c < _barriers_count; c++) {
 52       _barriers[c] = barriers.at(c);
 53     }
 54   }
 55 }
 56 
 57 ShenandoahNMethod::~ShenandoahNMethod() {
 58   if (_oops != nullptr) {
 59     FREE_C_HEAP_ARRAY(oop*, _oops);
 60   }
 61   if (_barriers != nullptr) {
 62     FREE_C_HEAP_ARRAY(ShenandoahNMethodBarrier, _barriers);
 63   }
 64 }
 65 
 66 void ShenandoahNMethod::update() {
 67   ResourceMark rm;
 68   bool non_immediate_oops = false;
 69   GrowableArray<oop*> oops;
 70   GrowableArray<ShenandoahNMethodBarrier> barriers;
 71 
 72   parse(nm(), oops, non_immediate_oops, barriers);
 73   if (oops.length() != _oops_count) {
 74     if (_oops != nullptr) {
 75       FREE_C_HEAP_ARRAY(oop*, _oops);
 76       _oops = nullptr;
 77     }
 78 
 79     _oops_count = oops.length();
 80     if (_oops_count > 0) {
 81       _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC);
 82     }
 83   }
 84 
 85   for (int index = 0; index < _oops_count; index ++) {
 86     _oops[index] = oops.at(index);
 87   }
 88   _has_non_immed_oops = non_immediate_oops;
 89 
 90   assert_same_oops();
 91 }
 92 
 93 void ShenandoahNMethod::parse(nmethod* nm, GrowableArray<oop*>& oops, bool& has_non_immed_oops, GrowableArray<ShenandoahNMethodBarrier>& barriers) {
 94   has_non_immed_oops = false;

 95   RelocIterator iter(nm);
 96   while (iter.next()) {
 97     switch (iter.type()) {
 98       case relocInfo::oop_type: {
 99         oop_Relocation* r = iter.oop_reloc();
100         if (!r->oop_is_immediate()) {
101           // Non-immediate oop found
102           has_non_immed_oops = true;
103           break;
104         }
105 
106         oop value = r->oop_value();
107         if (value != nullptr) {
108           oop* addr = r->oop_addr();
109           shenandoah_assert_correct(addr, value);
110           shenandoah_assert_not_in_cset_except(addr, value, ShenandoahHeap::heap()->cancelled_gc());
111           shenandoah_assert_not_forwarded(addr, value);
112           // Non-null immediate oop found. null oops can safely be
113           // ignored since the method will be re-registered if they
114           // are later patched to be non-null.
115           oops.push(addr);
116         }
117         break;
118       }
119       case relocInfo::barrier_type: {
120         assert(ShenandoahGCStateCheckHotpatch, "Who emits these?");
121         barrier_Relocation* r = iter.barrier_reloc();
122 
123         // TODO: Move to assembler?
124 #ifdef AMD64
125         NativeInstruction* ni = nativeInstruction_at(r->addr());
126         assert(ni->is_jump(), "Initial code version: GC barrier fastpath must be a jump");
127         NativeJump* jmp = nativeJump_at(r->addr());
128 
129         ShenandoahNMethodBarrier b;
130         b._barrier_pc = r->addr();
131         b._stub_addr = jmp->jump_destination();
132         // TODO: Can technically figure out which GC state we care about in this reloc.
133         // b._gc_state_fast_bit = r->format();
134         barriers.push(b);
135 #else
136         Unimplemented();
137 #endif
138 
139         break;
140       }
141       default:
142         // We do not care about other relocations.
143         break;





144     }
145   }
146 }
147 
148 ShenandoahNMethod* ShenandoahNMethod::for_nmethod(nmethod* nm) {
149   ResourceMark rm;
150   bool non_immediate_oops = false;
151   GrowableArray<oop*> oops;
152   GrowableArray<ShenandoahNMethodBarrier> barriers;
153 
154   parse(nm, oops, non_immediate_oops, barriers);
155   return new ShenandoahNMethod(nm, oops, non_immediate_oops, barriers);
156 }
157 
158 void ShenandoahNMethod::heal_nmethod(nmethod* nm) {
159   ShenandoahNMethod* data = gc_data(nm);
160   assert(data != nullptr, "Sanity");
161   assert(data->lock()->owned_by_self(), "Must hold the lock");
162 
163   ShenandoahHeap* const heap = ShenandoahHeap::heap();
164   if (heap->is_concurrent_weak_root_in_progress() ||
165       heap->is_concurrent_strong_root_in_progress()) {
166     ShenandoahEvacOOMScope evac_scope;
167     heal_nmethod_metadata(data);
168   } else if (heap->is_concurrent_mark_in_progress()) {
169     ShenandoahKeepAliveClosure cl;
170     data->oops_do(&cl);
171   } else {
172     // There is possibility that GC is cancelled when it arrives final mark.
173     // In this case, concurrent root phase is skipped and degenerated GC should be
174     // followed, where nmethods are disarmed.
175   }
176 
177   // Update all barriers
178   data->update_barriers();
179 }
180 
181 #ifdef AMD64
182 void insert_5_byte_nop(address pc) {
183   *(pc + 0) = 0x0F;
184   *(pc + 1) = 0x1F;
185   *(pc + 2) = 0x44;
186   *(pc + 3) = 0x00;
187   *(pc + 4) = 0x00;
188   ICache::invalidate_range(pc, 5);
189 }
190 
191 bool is_5_byte_nop(address pc) {
192   if (*(pc + 0) != 0x0F) return false;
193   if (*(pc + 1) != 0x1F) return false;
194   if (*(pc + 2) != 0x44) return false;
195   if (*(pc + 3) != 0x00) return false;
196   if (*(pc + 4) != 0x00) return false;
197   return true;
198 }
199 #endif
200 
201 void ShenandoahNMethod::update_barriers() {
202   if (!ShenandoahGCStateCheckHotpatch) return;
203 
204   ShenandoahHeap* heap = ShenandoahHeap::heap();
205 
206   for (int c = 0; c < _barriers_count; c++) {
207     ShenandoahNMethodBarrier& barrier = _barriers[c];
208 
209     address pc = barrier._barrier_pc;
210     NativeInstruction* ni = nativeInstruction_at(pc);
211 
212     // TODO: This should really be in assembler?
213  #ifdef AMD64
214     if (heap->is_idle()) {
215       // Heap is idle: insert nops
216       if (ni->is_jump()) {
217         insert_5_byte_nop(pc);
218       } else {
219         assert(is_5_byte_nop(pc), "Sanity: should already be nop at PC " PTR_FORMAT ": %02x%02x%02x%02x%02x",
220                p2i(pc), *(pc + 0), *(pc + 1), *(pc + 2), *(pc + 3), *(pc + 4));
221       }
222     } else {
223       // Heap is active: insert jumps to barrier stubs
224       if (is_5_byte_nop(pc)) {
225         NativeJump::insert(pc, barrier._stub_addr);
226       } else {
227         assert(ni->is_jump(), "Sanity: should already be jump at PC " PTR_FORMAT ": %02x%02x%02x%02x%02x",
228               p2i(pc), *(pc + 0), *(pc + 1), *(pc + 2), *(pc + 3), *(pc + 4));
229       }
230     }
231 #else
232     Unimplemented();
233 #endif
234   }
235 }
236 
237 #ifdef ASSERT
238 void ShenandoahNMethod::assert_correct() {
239   ShenandoahHeap* heap = ShenandoahHeap::heap();
240   for (int c = 0; c < _oops_count; c++) {
241     oop *loc = _oops[c];
242     assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*");
243     oop o = RawAccess<>::oop_load(loc);
244     shenandoah_assert_correct_except(loc, o, o == nullptr || heap->is_full_gc_move_in_progress());
245   }
246 
247   oop* const begin = _nm->oops_begin();
248   oop* const end = _nm->oops_end();
249   for (oop* p = begin; p < end; p++) {
250     if (*p != Universe::non_oop_word()) {
251       oop o = RawAccess<>::oop_load(p);
252       shenandoah_assert_correct_except(p, o, o == nullptr || heap->is_full_gc_move_in_progress());
253     }
254   }

285     assert(oops->contains(_oops[index]), "Must contain this oop");
286   }
287 
288   for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) {
289     if (*p == Universe::non_oop_word()) continue;
290     count++;
291     assert(oops->contains(p), "Must contain this oop");
292   }
293 
294   if (oops->length() < count) {
295     stringStream debug_stream;
296     debug_stream.print_cr("detected locs: %d", oops->length());
297     for (int i = 0; i < oops->length(); i++) {
298       debug_stream.print_cr("-> " PTR_FORMAT, p2i(oops->at(i)));
299     }
300     debug_stream.print_cr("recorded oops: %d", _oops_count);
301     for (int i = 0; i < _oops_count; i++) {
302       debug_stream.print_cr("-> " PTR_FORMAT, p2i(_oops[i]));
303     }
304     GrowableArray<oop*> check;
305     GrowableArray<ShenandoahNMethodBarrier> barriers;
306     bool non_immed;
307     parse(nm(), check, non_immed, barriers);
308     debug_stream.print_cr("check oops: %d", check.length());
309     for (int i = 0; i < check.length(); i++) {
310       debug_stream.print_cr("-> " PTR_FORMAT, p2i(check.at(i)));
311     }
312     fatal("Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT "\n%s",
313           oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()), debug_stream.freeze());
314   }
315 }
316 #endif
317 
318 ShenandoahNMethodTable::ShenandoahNMethodTable() :
319   _heap(ShenandoahHeap::heap()),
320   _index(0),
321   _itr_cnt(0) {
322   _list = new ShenandoahNMethodList(minSize);
323 }
324 
325 ShenandoahNMethodTable::~ShenandoahNMethodTable() {
326   assert(_list != nullptr, "Sanity");
327   _list->release();
328 }
329 
330 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) {
331   assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held");
332   assert(_index >= 0 && _index <= _list->size(), "Sanity");
333 
334   ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
335 
336   if (data != nullptr) {
337     assert(contain(nm), "Must have been registered");
338     assert(nm == data->nm(), "Must be same nmethod");
339     // Prevent updating a nmethod while concurrent iteration is in progress.
340     wait_until_concurrent_iteration_done();
341     ShenandoahNMethodLocker data_locker(data->lock());
342     data->update();
343     data->update_barriers();
344   } else {
345     // For a new nmethod, we can safely append it to the list, because
346     // concurrent iteration will not touch it.
347     data = ShenandoahNMethod::for_nmethod(nm);
348     data->update_barriers();
349     assert(data != nullptr, "Sanity");
350     ShenandoahNMethod::attach_gc_data(nm, data);
351     ShenandoahLocker locker(&_lock);
352     log_register_nmethod(nm);
353     append(data);
354   }
355   // Disarm new nmethod
356   ShenandoahNMethod::disarm_nmethod(nm);
357 }
358 
359 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) {
360   assert_locked_or_safepoint(CodeCache_lock);
361 
362   ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm);
363   assert(data != nullptr, "Sanity");
364   log_unregister_nmethod(nm);
365   ShenandoahLocker locker(&_lock);
366   assert(contain(nm), "Must have been registered");
367 
368   int idx = index_of(nm);
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