1 /*
2 * Copyright (c) 1998, 2013, 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 "compiler/compileLog.hpp"
27 #include "interpreter/linkResolver.hpp"
28 #include "memory/universe.inline.hpp"
29 #include "oops/objArrayKlass.hpp"
30 #include "oops/valueArrayKlass.hpp"
31 #include "opto/addnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/memnode.hpp"
34 #include "opto/parse.hpp"
35 #include "opto/rootnode.hpp"
36 #include "opto/runtime.hpp"
37 #include "opto/subnode.hpp"
38 #include "opto/valuetypenode.hpp"
39 #include "runtime/deoptimization.hpp"
40 #include "runtime/handles.inline.hpp"
41
42 //=============================================================================
43 // Helper methods for _get* and _put* bytecodes
44 //=============================================================================
45 bool Parse::static_field_ok_in_clinit(ciField *field, ciMethod *method) {
46 // Could be the field_holder's <clinit> method, or <clinit> for a subklass.
47 // Better to check now than to Deoptimize as soon as we execute
48 assert( field->is_static(), "Only check if field is static");
49 // is_being_initialized() is too generous. It allows access to statics
50 // by threads that are not running the <clinit> before the <clinit> finishes.
51 // return field->holder()->is_being_initialized();
52
53 // The following restriction is correct but conservative.
54 // It is also desirable to allow compilation of methods called from <clinit>
55 // but this generated code will need to be made safe for execution by
56 // other threads, or the transition from interpreted to compiled code would
57 // need to be guarded.
58 ciInstanceKlass *field_holder = field->holder();
59
60 bool access_OK = false;
61 if (method->holder()->is_subclass_of(field_holder)) {
62 if (method->is_static()) {
63 if (method->name() == ciSymbol::class_initializer_name()) {
64 // OK to access static fields inside initializer
65 access_OK = true;
66 }
67 } else {
68 if (method->name() == ciSymbol::object_initializer_name()) {
69 // It's also OK to access static fields inside a constructor,
70 // because any thread calling the constructor must first have
71 // synchronized on the class by executing a '_new' bytecode.
72 access_OK = true;
73 }
74 }
75 }
76
77 return access_OK;
78
79 }
80
81
82 void Parse::do_field_access(bool is_get, bool is_field) {
83 bool will_link;
84 ciField* field = iter().get_field(will_link);
85 assert(will_link, "getfield: typeflow responsibility");
86
87 ciInstanceKlass* field_holder = field->holder();
88
89 if (is_field == field->is_static()) {
90 // Interpreter will throw java_lang_IncompatibleClassChangeError
91 // Check this before allowing <clinit> methods to access static fields
92 uncommon_trap(Deoptimization::Reason_unhandled,
93 Deoptimization::Action_none);
94 return;
95 }
96
97 if (!is_field && !field_holder->is_initialized()) {
98 if (!static_field_ok_in_clinit(field, method())) {
99 uncommon_trap(Deoptimization::Reason_uninitialized,
100 Deoptimization::Action_reinterpret,
101 NULL, "!static_field_ok_in_clinit");
102 return;
103 }
104 }
105
106 // Deoptimize on putfield writes to call site target field.
107 if (!is_get && field->is_call_site_target()) {
108 uncommon_trap(Deoptimization::Reason_unhandled,
109 Deoptimization::Action_reinterpret,
110 NULL, "put to call site target field");
111 return;
112 }
113
114 assert(field->will_link(method()->holder(), bc()), "getfield: typeflow responsibility");
115
116 // Note: We do not check for an unloaded field type here any more.
117
118 // Generate code for the object pointer.
119 Node* obj;
120 if (is_field) {
121 int obj_depth = is_get ? 0 : field->type()->size();
122 obj = null_check(peek(obj_depth));
123 // Compile-time detect of null-exception?
124 if (stopped()) return;
125
126 #ifdef ASSERT
127 const TypeInstPtr *tjp = TypeInstPtr::make(TypePtr::NotNull, iter().get_declared_field_holder());
128 assert(_gvn.type(obj)->higher_equal(tjp), "cast_up is no longer needed");
129 #endif
130
131 if (is_get) {
132 (void) pop(); // pop receiver before getting
133 do_get_xxx(obj, field, is_field);
134 } else {
135 do_put_xxx(obj, field, is_field);
136 (void) pop(); // pop receiver after putting
137 }
138 } else {
139 const TypeInstPtr* tip = TypeInstPtr::make(field_holder->java_mirror());
140 obj = _gvn.makecon(tip);
141 if (is_get) {
142 do_get_xxx(obj, field, is_field);
143 } else {
144 do_put_xxx(obj, field, is_field);
145 }
146 }
147 }
148
149 void Parse::do_vgetfield() {
150 // fixme null/top check?
151 bool will_link;
152 ciField* field = iter().get_field(will_link);
153 BasicType bt = field->layout_type();
154 ValueTypeNode* vt = pop()->as_ValueType();
155 Node* value = vt->field_value_by_offset(field->offset());
156 push_node(bt, value);
157 }
158
159 void Parse::do_get_xxx(Node* obj, ciField* field, bool is_field) {
160 BasicType bt = field->layout_type();
161 // Does this field have a constant value? If so, just push the value.
162 if (field->is_constant()) {
163 // final or stable field
164 const Type* con_type = Type::make_constant(field, obj);
165 if (con_type != NULL) {
166 Node* con = makecon(con_type);
167 if (bt == T_VALUETYPE) {
168 // Load value type from constant oop
169 con = ValueTypeNode::make(gvn(), map()->memory(), con);
170 }
171 push_node(con_type->basic_type(), con);
172 return;
173 }
174 }
175
176 ciType* field_klass = field->type();
177 bool is_vol = field->is_volatile();
178
179 // Compute address and memory type.
180 int offset = field->offset_in_bytes();
181 const TypePtr* adr_type = C->alias_type(field)->adr_type();
182 Node *adr = basic_plus_adr(obj, obj, offset);
183
184 // Build the resultant type of the load
185 const Type *type;
186
187 bool must_assert_null = false;
188
189 if (bt == T_OBJECT || bt == T_VALUETYPE) {
190 if (!field->type()->is_loaded()) {
191 type = TypeInstPtr::BOTTOM;
192 must_assert_null = true;
193 } else if (field->is_constant() && field->is_static()) {
194 // This can happen if the constant oop is non-perm.
195 ciObject* con = field->constant_value().as_object();
196 // Do not "join" in the previous type; it doesn't add value,
197 // and may yield a vacuous result if the field is of interface type.
198 type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
199 assert(type != NULL, "field singleton type must be consistent");
200 } else {
201 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
202 }
203 } else {
204 type = Type::get_const_basic_type(bt);
205 }
206 if (support_IRIW_for_not_multiple_copy_atomic_cpu && field->is_volatile()) {
207 insert_mem_bar(Op_MemBarVolatile); // StoreLoad barrier
208 }
209
210 // Build the load.
211 //
212 MemNode::MemOrd mo = is_vol ? MemNode::acquire : MemNode::unordered;
213 bool needs_atomic_access = is_vol || AlwaysAtomicAccesses;
214 Node* ld = NULL;
215 if (bt == T_VALUETYPE && !field->is_static()) {
216 // Load flattened value type from non-static field
217 ld = ValueTypeNode::make(_gvn, field_klass->as_value_klass(), map()->memory(), obj, obj, field->holder(), offset);
218 } else {
219 ld = make_load(NULL, adr, type, bt, adr_type, mo, LoadNode::DependsOnlyOnTest, needs_atomic_access);
220 }
221
222 // Adjust Java stack
223 if (type2size[bt] == 1)
224 push(ld);
225 else
226 push_pair(ld);
227
228 if (must_assert_null) {
229 // Do not take a trap here. It's possible that the program
230 // will never load the field's class, and will happily see
231 // null values in this field forever. Don't stumble into a
232 // trap for such a program, or we might get a long series
233 // of useless recompilations. (Or, we might load a class
234 // which should not be loaded.) If we ever see a non-null
235 // value, we will then trap and recompile. (The trap will
236 // not need to mention the class index, since the class will
237 // already have been loaded if we ever see a non-null value.)
238 // uncommon_trap(iter().get_field_signature_index());
239 if (PrintOpto && (Verbose || WizardMode)) {
240 method()->print_name(); tty->print_cr(" asserting nullness of field at bci: %d", bci());
241 }
242 if (C->log() != NULL) {
243 C->log()->elem("assert_null reason='field' klass='%d'",
244 C->log()->identify(field->type()));
245 }
246 // If there is going to be a trap, put it at the next bytecode:
247 set_bci(iter().next_bci());
248 null_assert(peek());
249 set_bci(iter().cur_bci()); // put it back
250 }
251
252 // If reference is volatile, prevent following memory ops from
253 // floating up past the volatile read. Also prevents commoning
254 // another volatile read.
255 if (field->is_volatile()) {
256 // Memory barrier includes bogus read of value to force load BEFORE membar
257 insert_mem_bar(Op_MemBarAcquire, ld);
258 }
259 }
260
261 void Parse::do_put_xxx(Node* obj, ciField* field, bool is_field) {
262 bool is_vol = field->is_volatile();
263 // If reference is volatile, prevent following memory ops from
264 // floating down past the volatile write. Also prevents commoning
265 // another volatile read.
266 if (is_vol) insert_mem_bar(Op_MemBarRelease);
267
268 // Compute address and memory type.
269 int offset = field->offset_in_bytes();
270 const TypePtr* adr_type = C->alias_type(field)->adr_type();
271 Node* adr = basic_plus_adr(obj, obj, offset);
272 BasicType bt = field->layout_type();
273 // Value to be stored
274 Node* val = type2size[bt] == 1 ? pop() : pop_pair();
275 // Round doubles before storing
276 if (bt == T_DOUBLE) val = dstore_rounding(val);
277
278 // Conservatively release stores of object references.
279 const MemNode::MemOrd mo =
280 is_vol ?
281 // Volatile fields need releasing stores.
282 MemNode::release :
283 // Non-volatile fields also need releasing stores if they hold an
284 // object reference, because the object reference might point to
285 // a freshly created object.
286 StoreNode::release_if_reference(bt);
287
288 // Store the value.
289 if (bt == T_OBJECT || bt == T_VALUETYPE) {
290 const TypeOopPtr* field_type;
291 if (!field->type()->is_loaded()) {
292 field_type = TypeInstPtr::BOTTOM;
293 } else {
294 field_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
295 }
296 if (bt == T_VALUETYPE && !field->is_static()) {
297 // Store flattened value type to non-static field
298 val->as_ValueType()->store(this, obj, obj, field->holder(), offset);
299 } else {
300 store_oop_to_object(control(), obj, adr, adr_type, val, field_type, bt, mo);
301 }
302 } else {
303 bool needs_atomic_access = is_vol || AlwaysAtomicAccesses;
304 store_to_memory(control(), adr, val, bt, adr_type, mo, needs_atomic_access);
305 }
306
307 // If reference is volatile, prevent following volatiles ops from
308 // floating up before the volatile write.
309 if (is_vol) {
310 // If not multiple copy atomic, we do the MemBarVolatile before the load.
311 if (!support_IRIW_for_not_multiple_copy_atomic_cpu) {
312 insert_mem_bar(Op_MemBarVolatile); // Use fat membar
313 }
314 // Remember we wrote a volatile field.
315 // For not multiple copy atomic cpu (ppc64) a barrier should be issued
316 // in constructors which have such stores. See do_exits() in parse1.cpp.
317 if (is_field) {
318 set_wrote_volatile(true);
319 }
320 }
321
322 if (is_field) {
323 set_wrote_fields(true);
324 }
325
326 // If the field is final, the rules of Java say we are in <init> or <clinit>.
327 // Note the presence of writes to final non-static fields, so that we
328 // can insert a memory barrier later on to keep the writes from floating
329 // out of the constructor.
330 // Any method can write a @Stable field; insert memory barriers after those also.
331 if (is_field && (field->is_final() || field->is_stable())) {
332 if (field->is_final()) {
333 set_wrote_final(true);
334 }
335 if (field->is_stable()) {
336 set_wrote_stable(true);
337 }
338
339 // Preserve allocation ptr to create precedent edge to it in membar
340 // generated on exit from constructor.
341 // Can't bind stable with its allocation, only record allocation for final field.
342 if (field->is_final() && AllocateNode::Ideal_allocation(obj, &_gvn) != NULL) {
343 set_alloc_with_final(obj);
344 }
345 }
346 }
347
348 //=============================================================================
349
350 void Parse::do_newarray() {
351 bool will_link;
352 ciKlass* klass = iter().get_klass(will_link);
353
354 // Uncommon Trap when class that array contains is not loaded
355 // we need the loaded class for the rest of graph; do not
356 // initialize the container class (see Java spec)!!!
357 assert(will_link, "newarray: typeflow responsibility");
358
359 ciArrayKlass* array_klass = ciArrayKlass::make(klass);
360 // Check that array_klass object is loaded
361 if (!array_klass->is_loaded()) {
362 // Generate uncommon_trap for unloaded array_class
363 uncommon_trap(Deoptimization::Reason_unloaded,
364 Deoptimization::Action_reinterpret,
365 array_klass);
366 return;
367 } else if (array_klass->element_klass() != NULL &&
368 array_klass->element_klass()->is_valuetype() &&
369 !array_klass->element_klass()->as_value_klass()->is_initialized()) {
370 uncommon_trap(Deoptimization::Reason_uninitialized,
371 Deoptimization::Action_reinterpret,
372 NULL);
373 return;
374 }
375
376 kill_dead_locals();
377
378 const TypeKlassPtr* array_klass_type = TypeKlassPtr::make(array_klass);
379 Node* count_val = pop();
380 Node* obj = new_array(makecon(array_klass_type), count_val, 1);
381 push(obj);
382 }
383
384
385 void Parse::do_newarray(BasicType elem_type) {
386 kill_dead_locals();
387
388 Node* count_val = pop();
389 const TypeKlassPtr* array_klass = TypeKlassPtr::make(ciTypeArrayKlass::make(elem_type));
390 Node* obj = new_array(makecon(array_klass), count_val, 1);
391 // Push resultant oop onto stack
392 push(obj);
393 }
394
395 // Expand simple expressions like new int[3][5] and new Object[2][nonConLen].
396 // Also handle the degenerate 1-dimensional case of anewarray.
397 Node* Parse::expand_multianewarray(ciArrayKlass* array_klass, Node* *lengths, int ndimensions, int nargs) {
398 Node* length = lengths[0];
399 assert(length != NULL, "");
400 Node* array = new_array(makecon(TypeKlassPtr::make(array_klass)), length, nargs);
401 if (ndimensions > 1) {
402 jint length_con = find_int_con(length, -1);
403 guarantee(length_con >= 0, "non-constant multianewarray");
404 ciArrayKlass* array_klass_1 = array_klass->as_obj_array_klass()->element_klass()->as_array_klass();
405 const TypePtr* adr_type = TypeAryPtr::OOPS;
406 const TypeOopPtr* elemtype = _gvn.type(array)->is_aryptr()->elem()->make_oopptr();
407 const intptr_t header = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
408 for (jint i = 0; i < length_con; i++) {
409 Node* elem = expand_multianewarray(array_klass_1, &lengths[1], ndimensions-1, nargs);
410 intptr_t offset = header + ((intptr_t)i << LogBytesPerHeapOop);
411 Node* eaddr = basic_plus_adr(array, offset);
412 store_oop_to_array(control(), array, eaddr, adr_type, elem, elemtype, T_OBJECT, MemNode::unordered);
413 }
414 }
415 return array;
416 }
417
418 void Parse::do_multianewarray() {
419 int ndimensions = iter().get_dimensions();
420
421 // the m-dimensional array
422 bool will_link;
423 ciArrayKlass* array_klass = iter().get_klass(will_link)->as_array_klass();
424 assert(will_link, "multianewarray: typeflow responsibility");
425
426 // Note: Array classes are always initialized; no is_initialized check.
427
428 kill_dead_locals();
429
430 // get the lengths from the stack (first dimension is on top)
431 Node** length = NEW_RESOURCE_ARRAY(Node*, ndimensions + 1);
432 length[ndimensions] = NULL; // terminating null for make_runtime_call
433 int j;
434 for (j = ndimensions-1; j >= 0 ; j--) length[j] = pop();
435
436 // The original expression was of this form: new T[length0][length1]...
437 // It is often the case that the lengths are small (except the last).
438 // If that happens, use the fast 1-d creator a constant number of times.
439 const jint expand_limit = MIN2((jint)MultiArrayExpandLimit, 100);
440 jint expand_count = 1; // count of allocations in the expansion
441 jint expand_fanout = 1; // running total fanout
442 for (j = 0; j < ndimensions-1; j++) {
443 jint dim_con = find_int_con(length[j], -1);
444 expand_fanout *= dim_con;
445 expand_count += expand_fanout; // count the level-J sub-arrays
446 if (dim_con <= 0
447 || dim_con > expand_limit
448 || expand_count > expand_limit) {
449 expand_count = 0;
450 break;
451 }
452 }
453
454 // Can use multianewarray instead of [a]newarray if only one dimension,
455 // or if all non-final dimensions are small constants.
456 if (ndimensions == 1 || (1 <= expand_count && expand_count <= expand_limit)) {
457 Node* obj = NULL;
458 // Set the original stack and the reexecute bit for the interpreter
459 // to reexecute the multianewarray bytecode if deoptimization happens.
460 // Do it unconditionally even for one dimension multianewarray.
461 // Note: the reexecute bit will be set in GraphKit::add_safepoint_edges()
462 // when AllocateArray node for newarray is created.
463 { PreserveReexecuteState preexecs(this);
464 inc_sp(ndimensions);
465 // Pass 0 as nargs since uncommon trap code does not need to restore stack.
466 obj = expand_multianewarray(array_klass, &length[0], ndimensions, 0);
467 } //original reexecute and sp are set back here
468 push(obj);
469 return;
470 }
471
472 address fun = NULL;
473 switch (ndimensions) {
474 case 1: ShouldNotReachHere(); break;
475 case 2: fun = OptoRuntime::multianewarray2_Java(); break;
476 case 3: fun = OptoRuntime::multianewarray3_Java(); break;
477 case 4: fun = OptoRuntime::multianewarray4_Java(); break;
478 case 5: fun = OptoRuntime::multianewarray5_Java(); break;
479 };
480 Node* c = NULL;
481
482 if (fun != NULL) {
483 c = make_runtime_call(RC_NO_LEAF | RC_NO_IO,
484 OptoRuntime::multianewarray_Type(ndimensions),
485 fun, NULL, TypeRawPtr::BOTTOM,
486 makecon(TypeKlassPtr::make(array_klass)),
487 length[0], length[1], length[2],
488 (ndimensions > 2) ? length[3] : NULL,
489 (ndimensions > 3) ? length[4] : NULL);
490 } else {
491 // Create a java array for dimension sizes
492 Node* dims = NULL;
493 { PreserveReexecuteState preexecs(this);
494 inc_sp(ndimensions);
495 Node* dims_array_klass = makecon(TypeKlassPtr::make(ciArrayKlass::make(ciType::make(T_INT))));
496 dims = new_array(dims_array_klass, intcon(ndimensions), 0);
497
498 // Fill-in it with values
499 for (j = 0; j < ndimensions; j++) {
500 Node *dims_elem = array_element_address(dims, intcon(j), T_INT);
501 store_to_memory(control(), dims_elem, length[j], T_INT, TypeAryPtr::INTS, MemNode::unordered);
502 }
503 }
504
505 c = make_runtime_call(RC_NO_LEAF | RC_NO_IO,
506 OptoRuntime::multianewarrayN_Type(),
507 OptoRuntime::multianewarrayN_Java(), NULL, TypeRawPtr::BOTTOM,
508 makecon(TypeKlassPtr::make(array_klass)),
509 dims);
510 }
511 make_slow_call_ex(c, env()->Throwable_klass(), false);
512
513 Node* res = _gvn.transform(new ProjNode(c, TypeFunc::Parms));
514
515 const Type* type = TypeOopPtr::make_from_klass_raw(array_klass);
516
517 // Improve the type: We know it's not null, exact, and of a given length.
518 type = type->is_ptr()->cast_to_ptr_type(TypePtr::NotNull);
519 type = type->is_aryptr()->cast_to_exactness(true);
520
521 const TypeInt* ltype = _gvn.find_int_type(length[0]);
522 if (ltype != NULL)
523 type = type->is_aryptr()->cast_to_size(ltype);
524
525 // We cannot sharpen the nested sub-arrays, since the top level is mutable.
526
527 Node* cast = _gvn.transform( new CheckCastPPNode(control(), res, type) );
528 push(cast);
529
530 // Possible improvements:
531 // - Make a fast path for small multi-arrays. (W/ implicit init. loops.)
532 // - Issue CastII against length[*] values, to TypeInt::POS.
533 }
534
535 void Parse::do_vbox() {
536 // Obtain target type (from bytecodes)
537 bool will_link;
538 ciKlass* target_klass = iter().get_klass(will_link);
539 guarantee(will_link, "vbox: Value-capable class must be loaded");
540 guarantee(target_klass->is_instance_klass(), "vbox: Target class must be an instance type");
541
542 // Obtain source type
543 const TypeValueType* source_type = gvn().type(peek())->isa_valuetype();
544 guarantee(source_type != NULL && source_type->value_klass() != NULL && source_type->value_klass()->is_loaded(),
545 "vbox: Source class must be a value type and must be loaded");
546
547 ciInstanceKlass* target_vcc_klass = target_klass->as_instance_klass();
548 guarantee(target_vcc_klass->has_derive_value_type(), "vbox: Target class must have a derived value type class linked");
549 ciValueKlass* target_dvt_klass = target_vcc_klass->derive_value_type()->as_value_klass();
550
551 kill_dead_locals();
552
553 ValueTypeNode* vt = peek()->as_ValueType();
554 if (gvn().type(vt->get_oop())->higher_equal(TypePtr::NULL_PTR)) {
555 // The type of both the value type instance and of the target is known.
556 // The value type that is about to be boxed has no oop associated
557 // (i.e., the value type has not been allocated yet). To be able to
558 // allocate the value type, the compiler must have saved type information
559 // into the value type. The bytecode instruction gives the exact type of
560 // the target.
561 if(!source_type->value_klass()->derive_value_type()->is_subclass_of(target_vcc_klass)) {
562 builtin_throw(Deoptimization::Reason_class_check);
563 guarantee(stopped(), "A ClassCastException must be always thrown on this path");
564 return;
565 }
566 } else {
567 // The value type has an associated oop, so the compiler generates
568 // a typecheck for that oop (i.e., the class of the oop is supposed to
569 // be subclass of the value type derived from the target).
570 gen_checkcast(vt->get_oop(), makecon(TypeKlassPtr::make(target_dvt_klass)));
571 }
572
573 pop();
574
575 // Create new object
576 Node* kls = makecon(TypeKlassPtr::make(target_vcc_klass));
577 Node* obj = new_instance(kls);
578
579 // Store all field values to the newly created object.
580 // The code below relies on the assumption that the VCC has the
581 // same memory layout as the derived value type.
582 // TODO: Once the layout of the two is not the same, update code below.
583 vt->as_ValueType()->store_values(this, obj, obj, target_vcc_klass);
584
585 // Push the new object onto the stack
586 push(obj);
587 }
588
589 void Parse::do_vunbox() {
590 // Check if the VCC instance is null.
591 Node* obj = null_check(peek());
592
593 // Value determined to be null at compile time
594 if (stopped()) {
595 return;
596 }
597
598 // Obtain target type (from bytecodes)
599 bool will_link;
600 ciKlass* target_klass = iter().get_klass(will_link);
601 guarantee(will_link, "vunbox: Derived value type must be loaded");
602 guarantee(target_klass->is_valuetype(), "vunbox: Target class must be a value type");
603
604 // Obtain source type
605 const TypeOopPtr* source_type = gvn().type(obj)->isa_oopptr();
606 guarantee(source_type != NULL && source_type->klass() != NULL &&
607 source_type->klass()->is_instance_klass() && source_type->klass()->is_loaded(),
608 "vunbox: Source class must be an instance type and must be loaded");
609
610 ciValueKlass* target_dvt_klass = target_klass->as_value_klass();
611 guarantee(target_dvt_klass->has_derive_value_type(), "vunbox: Target class must have a value-capable class linked");
612 ciInstanceKlass* target_vcc_klass = target_dvt_klass->derive_value_type()->as_instance_klass();
613
614 // Check if the class of the source is a subclass of the value-capable class
615 // corresponding to the target.
616 // TOOD: Investigate if gen_checkcast can be used to perform the null-check above.
617 // A good occasion to do that seems when also implementing profiling of vunbox bytecodes.
618 gen_checkcast(obj, makecon(TypeKlassPtr::make(target_vcc_klass)));
619
620 // Remove object from the top of the stack
621 pop();
622
623 // Create a value type node with the corresponding type
624 Node* vt = ValueTypeNode::make(gvn(), target_dvt_klass, map()->memory(), obj, obj, target_vcc_klass, target_dvt_klass->first_field_offset());
625
626 // Push the value type onto the stack
627 push(vt);
628 }