1 /*
  2  * Copyright (c) 2020, 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 "ci/ciSymbols.hpp"
 27 #include "gc/shared/barrierSet.hpp"
 28 #include "opto/castnode.hpp"
 29 #include "opto/graphKit.hpp"
 30 #include "opto/phaseX.hpp"
 31 #include "opto/rootnode.hpp"
 32 #include "opto/vector.hpp"
 33 #include "utilities/macros.hpp"
 34 
 35 static bool is_vector_mask(ciKlass* klass) {
 36   return klass->is_subclass_of(ciEnv::current()->vector_VectorMask_klass());
 37 }
 38 
 39 static bool is_vector_shuffle(ciKlass* klass) {
 40   return klass->is_subclass_of(ciEnv::current()->vector_VectorShuffle_klass());
 41 }
 42 
 43 
 44 void PhaseVector::optimize_vector_boxes() {
 45   Compile::TracePhase tp("vector_elimination", &timers[_t_vector_elimination]);
 46 
 47   // Signal GraphKit it's post-parse phase.
 48   assert(C->inlining_incrementally() == false, "sanity");
 49   C->set_inlining_incrementally(true);
 50 
 51   C->igvn_worklist()->ensure_empty(); // should be done with igvn
 52 
 53   expand_vunbox_nodes();
 54   scalarize_vbox_nodes();
 55 
 56   C->inline_vector_reboxing_calls();
 57 
 58   expand_vbox_nodes();
 59   eliminate_vbox_alloc_nodes();
 60 
 61   C->set_inlining_incrementally(false);
 62 
 63   do_cleanup();
 64 }
 65 
 66 void PhaseVector::do_cleanup() {
 67   if (C->failing())  return;
 68   {
 69     Compile::TracePhase tp("vector_pru", &timers[_t_vector_pru]);
 70     ResourceMark rm;
 71     PhaseRemoveUseless pru(C->initial_gvn(), *C->igvn_worklist());
 72     if (C->failing())  return;
 73   }
 74   {
 75     Compile::TracePhase tp("incrementalInline_igvn", &timers[_t_vector_igvn]);
 76     _igvn.reset_from_gvn(C->initial_gvn());
 77     _igvn.optimize();
 78     if (C->failing())  return;
 79   }
 80   C->print_method(PHASE_ITER_GVN_BEFORE_EA, 3);
 81 }
 82 
 83 void PhaseVector::scalarize_vbox_nodes() {
 84   if (C->failing())  return;
 85 
 86   if (!EnableVectorReboxing) {
 87     return; // don't scalarize vector boxes
 88   }
 89 
 90   int macro_idx = C->macro_count() - 1;
 91   while (macro_idx >= 0) {
 92     Node * n = C->macro_node(macro_idx);
 93     assert(n->is_macro(), "only macro nodes expected here");
 94     if (n->Opcode() == Op_VectorBox) {
 95       VectorBoxNode* vbox = static_cast<VectorBoxNode*>(n);
 96       scalarize_vbox_node(vbox);
 97       if (C->failing())  return;
 98       C->print_method(PHASE_SCALARIZE_VBOX, 3, vbox);
 99     }
100     if (C->failing())  return;
101     macro_idx = MIN2(macro_idx - 1, C->macro_count() - 1);
102   }
103 }
104 
105 void PhaseVector::expand_vbox_nodes() {
106   if (C->failing())  return;
107 
108   int macro_idx = C->macro_count() - 1;
109   while (macro_idx >= 0) {
110     Node * n = C->macro_node(macro_idx);
111     assert(n->is_macro(), "only macro nodes expected here");
112     if (n->Opcode() == Op_VectorBox) {
113       VectorBoxNode* vbox = static_cast<VectorBoxNode*>(n);
114       expand_vbox_node(vbox);
115       if (C->failing())  return;
116     }
117     if (C->failing())  return;
118     macro_idx = MIN2(macro_idx - 1, C->macro_count() - 1);
119   }
120 }
121 
122 void PhaseVector::expand_vunbox_nodes() {
123   if (C->failing())  return;
124 
125   int macro_idx = C->macro_count() - 1;
126   while (macro_idx >= 0) {
127     Node * n = C->macro_node(macro_idx);
128     assert(n->is_macro(), "only macro nodes expected here");
129     if (n->Opcode() == Op_VectorUnbox) {
130       VectorUnboxNode* vec_unbox = static_cast<VectorUnboxNode*>(n);
131       expand_vunbox_node(vec_unbox);
132       if (C->failing())  return;
133       C->print_method(PHASE_EXPAND_VUNBOX, 3, vec_unbox);
134     }
135     if (C->failing())  return;
136     macro_idx = MIN2(macro_idx - 1, C->macro_count() - 1);
137   }
138 }
139 
140 void PhaseVector::eliminate_vbox_alloc_nodes() {
141   if (C->failing())  return;
142 
143   int macro_idx = C->macro_count() - 1;
144   while (macro_idx >= 0) {
145     Node * n = C->macro_node(macro_idx);
146     assert(n->is_macro(), "only macro nodes expected here");
147     if (n->Opcode() == Op_VectorBoxAllocate) {
148       VectorBoxAllocateNode* vbox_alloc = static_cast<VectorBoxAllocateNode*>(n);
149       eliminate_vbox_alloc_node(vbox_alloc);
150       if (C->failing())  return;
151       C->print_method(PHASE_ELIMINATE_VBOX_ALLOC, 3, vbox_alloc);
152     }
153     if (C->failing())  return;
154     macro_idx = MIN2(macro_idx - 1, C->macro_count() - 1);
155   }
156 }
157 
158 static JVMState* clone_jvms(Compile* C, SafePointNode* sfpt) {
159   JVMState* new_jvms = sfpt->jvms()->clone_shallow(C);
160   uint size = sfpt->req();
161   SafePointNode* map = new SafePointNode(size, new_jvms);
162   for (uint i = 0; i < size; i++) {
163     map->init_req(i, sfpt->in(i));
164   }
165   Node* mem = map->memory();
166   if (!mem->is_MergeMem()) {
167     // Since we are not in parsing, the SafePointNode does not guarantee that the memory
168     // input is necessarily a MergeMemNode. But we need to ensure that there is that
169     // MergeMemNode, since the GraphKit assumes the memory input of the map to be a
170     // MergeMemNode, so that it can directly access the memory slices.
171     PhaseGVN& gvn = *C->initial_gvn();
172     Node* mergemem = MergeMemNode::make(mem);
173     gvn.set_type_bottom(mergemem);
174     map->set_memory(mergemem);
175   }
176   new_jvms->set_map(map);
177   return new_jvms;
178 }
179 
180 void PhaseVector::scalarize_vbox_node(VectorBoxNode* vec_box) {
181   Node* vec_value = vec_box->in(VectorBoxNode::Value);
182   PhaseGVN& gvn = *C->initial_gvn();
183 
184   // Process merged VBAs
185 
186   if (EnableVectorAggressiveReboxing) {
187     Unique_Node_List calls(C->comp_arena());
188     for (DUIterator_Fast imax, i = vec_box->fast_outs(imax); i < imax; i++) {
189       Node* use = vec_box->fast_out(i);
190       if (use->is_CallJava()) {
191         CallJavaNode* call = use->as_CallJava();
192         if (call->has_non_debug_use(vec_box) && vec_box->in(VectorBoxNode::Box)->is_Phi()) {
193           calls.push(call);
194         }
195       }
196     }
197 
198     while (calls.size() > 0) {
199       CallJavaNode* call = calls.pop()->as_CallJava();
200       // Attach new VBA to the call and use it instead of Phi (VBA ... VBA).
201 
202       JVMState* jvms = clone_jvms(C, call);
203       GraphKit kit(jvms);
204       PhaseGVN& gvn = kit.gvn();
205 
206       // Adjust JVMS from post-call to pre-call state: put args on stack
207       uint nargs = call->method()->arg_size();
208       kit.ensure_stack(kit.sp() + nargs);
209       for (uint i = TypeFunc::Parms; i < call->tf()->domain()->cnt(); i++) {
210         kit.push(call->in(i));
211       }
212       jvms = kit.sync_jvms();
213 
214       Node* new_vbox = nullptr;
215       {
216         Node* vect = vec_box->in(VectorBoxNode::Value);
217         const TypeInstPtr* vbox_type = vec_box->box_type();
218         const TypeVect* vt = vec_box->vec_type();
219         BasicType elem_bt = vt->element_basic_type();
220         int num_elem = vt->length();
221 
222         new_vbox = kit.box_vector(vect, vbox_type, elem_bt, num_elem, /*deoptimize=*/true);
223 
224         kit.replace_in_map(vec_box, new_vbox);
225       }
226 
227       kit.dec_sp(nargs);
228       jvms = kit.sync_jvms();
229 
230       call->set_req(TypeFunc::Control , kit.control());
231       call->set_req(TypeFunc::I_O     , kit.i_o());
232       call->set_req(TypeFunc::Memory  , kit.reset_memory());
233       call->set_req(TypeFunc::FramePtr, kit.frameptr());
234       call->replace_edge(vec_box, new_vbox);
235 
236       C->record_for_igvn(call);
237     }
238   }
239 
240   // Process debug uses at safepoints
241   Unique_Node_List safepoints(C->comp_arena());
242 
243   Unique_Node_List worklist(C->comp_arena());
244   worklist.push(vec_box);
245   while (worklist.size() > 0) {
246     Node* n = worklist.pop();
247     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
248       Node* use = n->fast_out(i);
249       if (use->is_SafePoint()) {
250         SafePointNode* sfpt = use->as_SafePoint();
251         if (!sfpt->is_Call() || !sfpt->as_Call()->has_non_debug_use(n)) {
252           safepoints.push(sfpt);
253         }
254       } else if (use->is_ConstraintCast()) {
255         worklist.push(use); // reversed version of Node::uncast()
256       }
257     }
258   }
259 
260   ciInstanceKlass* iklass = vec_box->box_type()->instance_klass();
261   int n_fields = iklass->nof_nonstatic_fields();
262   assert(n_fields == 1, "sanity");
263 
264   // If a mask is feeding into safepoint[s], then its value should be
265   // packed into a boolean/byte vector first, this will simplify the
266   // re-materialization logic for both predicated and non-predicated
267   // targets.
268   bool is_mask = is_vector_mask(iklass);
269   if (is_mask && vec_value->Opcode() != Op_VectorStoreMask) {
270     const TypeVect* vt = vec_value->bottom_type()->is_vect();
271     BasicType bt = vt->element_basic_type();
272     vec_value = gvn.transform(VectorStoreMaskNode::make(gvn, vec_value, bt, vt->length()));
273   }
274 
275   while (safepoints.size() > 0) {
276     SafePointNode* sfpt = safepoints.pop()->as_SafePoint();
277 
278     uint first_ind = (sfpt->req() - sfpt->jvms()->scloff());
279     Node* sobj = new SafePointScalarObjectNode(vec_box->box_type(), vec_box, first_ind, sfpt->jvms()->depth(), n_fields);
280     sobj->init_req(0, C->root());
281     sfpt->add_req(vec_value);
282 
283     sobj = gvn.transform(sobj);
284 
285     JVMState *jvms = sfpt->jvms();
286 
287     jvms->set_endoff(sfpt->req());
288     // Now make a pass over the debug information replacing any references
289     // to the allocated object with vector value.
290     for (uint i = jvms->debug_start(); i < jvms->debug_end(); i++) {
291       Node* debug = sfpt->in(i);
292       if (debug != nullptr && debug->uncast(/*keep_deps*/false) == vec_box) {
293         sfpt->set_req(i, sobj);
294       }
295     }
296     C->record_for_igvn(sfpt);
297   }
298 }
299 
300 void PhaseVector::expand_vbox_node(VectorBoxNode* vec_box) {
301   if (vec_box->outcnt() > 0) {
302     VectorSet visited;
303     Node* vbox = vec_box->in(VectorBoxNode::Box);
304     Node* vect = vec_box->in(VectorBoxNode::Value);
305     Node* result = expand_vbox_node_helper(vbox, vect, vec_box->box_type(),
306                                            vec_box->vec_type(), visited);
307     C->gvn_replace_by(vec_box, result);
308     C->print_method(PHASE_EXPAND_VBOX, 3, vec_box);
309   }
310   C->remove_macro_node(vec_box);
311 }
312 
313 Node* PhaseVector::expand_vbox_node_helper(Node* vbox,
314                                            Node* vect,
315                                            const TypeInstPtr* box_type,
316                                            const TypeVect* vect_type,
317                                            VectorSet &visited) {
318   // JDK-8304948 shows an example that there may be a cycle in the graph.
319   if (visited.test_set(vbox->_idx)) {
320     assert(vbox->is_Phi(), "should be phi");
321     return vbox; // already visited
322   }
323 
324   // Handle the case when the allocation input to VectorBoxNode is a Proj.
325   // This is the normal case before expanding.
326   if (vbox->is_Proj() && vbox->in(0)->Opcode() == Op_VectorBoxAllocate) {
327     VectorBoxAllocateNode* vbox_alloc = static_cast<VectorBoxAllocateNode*>(vbox->in(0));
328     return expand_vbox_alloc_node(vbox_alloc, vect, box_type, vect_type);
329   }
330 
331   // Handle the case when both the allocation input and vector input to
332   // VectorBoxNode are Phi. This case is generated after the transformation of
333   // Phi: Phi (VectorBox1 VectorBox2) => VectorBox (Phi1 Phi2).
334   // With this optimization, the relative two allocation inputs of VectorBox1 and
335   // VectorBox2 are gathered into Phi1 now. Similarly, the original vector
336   // inputs of two VectorBox nodes are in Phi2.
337   //
338   // See PhiNode::merge_through_phi in cfg.cpp for more details.
339   if (vbox->is_Phi() && vect->is_Phi()) {
340     assert(vbox->as_Phi()->region() == vect->as_Phi()->region(), "");
341     for (uint i = 1; i < vbox->req(); i++) {
342       Node* new_box = expand_vbox_node_helper(vbox->in(i), vect->in(i),
343                                               box_type, vect_type, visited);
344       if (!new_box->is_Phi()) {
345         C->initial_gvn()->hash_delete(vbox);
346         vbox->set_req(i, new_box);
347       }
348     }
349     return C->initial_gvn()->transform(vbox);
350   }
351 
352   // Handle the case when the allocation input to VectorBoxNode is a phi
353   // but the vector input is not, which can definitely be the case if the
354   // vector input has been value-numbered. It seems to be safe to do by
355   // construction because VectorBoxNode and VectorBoxAllocate come in a
356   // specific order as a result of expanding an intrinsic call. After that, if
357   // any of the inputs to VectorBoxNode are value-numbered they can only
358   // move up and are guaranteed to dominate.
359   if (vbox->is_Phi() && (vect->is_Vector() || vect->is_LoadVector())) {
360     for (uint i = 1; i < vbox->req(); i++) {
361       Node* new_box = expand_vbox_node_helper(vbox->in(i), vect,
362                                               box_type, vect_type, visited);
363       if (!new_box->is_Phi()) {
364         C->initial_gvn()->hash_delete(vbox);
365         vbox->set_req(i, new_box);
366       }
367     }
368     return C->initial_gvn()->transform(vbox);
369   }
370 
371   assert(!vbox->is_Phi(), "should be expanded");
372   // TODO: assert that expanded vbox is initialized with the same value (vect).
373   return vbox; // already expanded
374 }
375 
376 Node* PhaseVector::expand_vbox_alloc_node(VectorBoxAllocateNode* vbox_alloc,
377                                           Node* value,
378                                           const TypeInstPtr* box_type,
379                                           const TypeVect* vect_type) {
380   JVMState* jvms = clone_jvms(C, vbox_alloc);
381   GraphKit kit(jvms);
382   PhaseGVN& gvn = kit.gvn();
383 
384   ciInstanceKlass* box_klass = box_type->instance_klass();
385   BasicType bt = vect_type->element_basic_type();
386   int num_elem = vect_type->length();
387 
388   bool is_mask = is_vector_mask(box_klass);
389   // If boxed mask value is present in a predicate register, it must be
390   // spilled to a vector though a VectorStoreMaskOperation before actual StoreVector
391   // operation to vector payload field.
392   if (is_mask && (value->bottom_type()->isa_vectmask() || bt != T_BOOLEAN)) {
393     value = gvn.transform(VectorStoreMaskNode::make(gvn, value, bt, num_elem));
394     // Although type of mask depends on its definition, in terms of storage everything is stored in boolean array.
395     bt = T_BOOLEAN;
396     assert(value->bottom_type()->is_vect()->element_basic_type() == bt,
397            "must be consistent with mask representation");
398   }
399 
400   // Generate array allocation for the field which holds the values.
401   const TypeKlassPtr* array_klass = TypeKlassPtr::make(ciTypeArrayKlass::make(bt));
402   Node* arr = kit.new_array(kit.makecon(array_klass), kit.intcon(num_elem), 1);
403 
404   // Store the vector value into the array.
405   // (The store should be captured by InitializeNode and turned into initialized store later.)
406   Node* arr_adr = kit.array_element_address(arr, kit.intcon(0), bt);
407   const TypePtr* arr_adr_type = arr_adr->bottom_type()->is_ptr();
408   Node* arr_mem = kit.memory(arr_adr);
409   Node* vstore = gvn.transform(StoreVectorNode::make(0,
410                                                      kit.control(),
411                                                      arr_mem,
412                                                      arr_adr,
413                                                      arr_adr_type,
414                                                      value,
415                                                      num_elem));
416   kit.set_memory(vstore, arr_adr_type);
417 
418   C->set_max_vector_size(MAX2(C->max_vector_size(), vect_type->length_in_bytes()));
419 
420   // Generate the allocate for the Vector object.
421   const TypeKlassPtr* klass_type = box_type->as_klass_type();
422   Node* klass_node = kit.makecon(klass_type);
423   Node* vec_obj = kit.new_instance(klass_node);
424 
425   // Store the allocated array into object.
426   ciField* field = ciEnv::current()->vector_VectorPayload_klass()->get_field_by_name(ciSymbols::payload_name(),
427                                                                                      ciSymbols::object_signature(),
428                                                                                      false);
429   assert(field != nullptr, "");
430   Node* vec_field = kit.basic_plus_adr(vec_obj, field->offset_in_bytes());
431   const TypePtr* vec_adr_type = vec_field->bottom_type()->is_ptr();
432 
433   // The store should be captured by InitializeNode and turned into initialized store later.
434   Node* field_store = gvn.transform(kit.access_store_at(vec_obj,
435                                                         vec_field,
436                                                         vec_adr_type,
437                                                         arr,
438                                                         TypeOopPtr::make_from_klass(field->type()->as_klass()),
439                                                         T_OBJECT,
440                                                         IN_HEAP));
441   kit.set_memory(field_store, vec_adr_type);
442 
443   kit.replace_call(vbox_alloc, vec_obj, true);
444   C->remove_macro_node(vbox_alloc);
445 
446   return vec_obj;
447 }
448 
449 void PhaseVector::expand_vunbox_node(VectorUnboxNode* vec_unbox) {
450   if (vec_unbox->outcnt() > 0) {
451     GraphKit kit;
452     PhaseGVN& gvn = kit.gvn();
453 
454     Node* obj = vec_unbox->obj();
455     const TypeInstPtr* tinst = gvn.type(obj)->isa_instptr();
456     ciInstanceKlass* from_kls = tinst->instance_klass();
457     const TypeVect* vt = vec_unbox->bottom_type()->is_vect();
458     BasicType bt = vt->element_basic_type();
459     BasicType masktype = bt;
460 
461     if (is_vector_mask(from_kls)) {
462       bt = T_BOOLEAN;
463     } else if (is_vector_shuffle(from_kls)) {
464       bt = T_BYTE;
465     }
466 
467     ciField* field = ciEnv::current()->vector_VectorPayload_klass()->get_field_by_name(ciSymbols::payload_name(),
468                                                                                        ciSymbols::object_signature(),
469                                                                                        false);
470     assert(field != nullptr, "");
471     int offset = field->offset_in_bytes();
472     Node* vec_adr = kit.basic_plus_adr(obj, offset);
473 
474     Node* mem = vec_unbox->mem();
475     Node* ctrl = vec_unbox->in(0);
476     Node* vec_field_ld;
477     {
478       DecoratorSet decorators = MO_UNORDERED | IN_HEAP;
479       C2AccessValuePtr addr(vec_adr, vec_adr->bottom_type()->is_ptr());
480       MergeMemNode* local_mem = MergeMemNode::make(mem);
481       gvn.record_for_igvn(local_mem);
482       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
483       C2OptAccess access(gvn, ctrl, local_mem, decorators, T_OBJECT, obj, addr);
484       const Type* type = TypeOopPtr::make_from_klass(field->type()->as_klass());
485       vec_field_ld = bs->load_at(access, type);
486     }
487 
488     // For proper aliasing, attach concrete payload type.
489     ciKlass* payload_klass = ciTypeArrayKlass::make(bt);
490     const Type* payload_type = TypeAryPtr::make_from_klass(payload_klass)->cast_to_ptr_type(TypePtr::NotNull);
491     vec_field_ld = gvn.transform(new CastPPNode(nullptr, vec_field_ld, payload_type));
492 
493     Node* adr = kit.array_element_address(vec_field_ld, gvn.intcon(0), bt);
494     const TypePtr* adr_type = adr->bottom_type()->is_ptr();
495     int num_elem = vt->length();
496     Node* vec_val_load = LoadVectorNode::make(0,
497                                               ctrl,
498                                               mem,
499                                               adr,
500                                               adr_type,
501                                               num_elem,
502                                               bt);
503     vec_val_load = gvn.transform(vec_val_load);
504 
505     C->set_max_vector_size(MAX2(C->max_vector_size(), vt->length_in_bytes()));
506 
507     if (is_vector_mask(from_kls)) {
508       vec_val_load = gvn.transform(new VectorLoadMaskNode(vec_val_load, TypeVect::makemask(masktype, num_elem)));
509     } else if (is_vector_shuffle(from_kls) && !vec_unbox->is_shuffle_to_vector()) {
510       assert(vec_unbox->bottom_type()->is_vect()->element_basic_type() == masktype, "expect shuffle type consistency");
511       vec_val_load = gvn.transform(new VectorLoadShuffleNode(vec_val_load, TypeVect::make(masktype, num_elem)));
512     }
513 
514     gvn.hash_delete(vec_unbox);
515     vec_unbox->disconnect_inputs(C);
516     C->gvn_replace_by(vec_unbox, vec_val_load);
517   }
518   C->remove_macro_node(vec_unbox);
519 }
520 
521 void PhaseVector::eliminate_vbox_alloc_node(VectorBoxAllocateNode* vbox_alloc) {
522   JVMState* jvms = clone_jvms(C, vbox_alloc);
523   GraphKit kit(jvms);
524   // Remove VBA, but leave a safepoint behind.
525   // Otherwise, it may end up with a loop without any safepoint polls.
526   kit.replace_call(vbox_alloc, kit.map(), true);
527   C->remove_macro_node(vbox_alloc);
528 }