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_holder->is_valuetype()) {
90 assert(is_get, "value type field store not supported");
91 BasicType bt = field->layout_type();
92 ValueTypeNode* vt = pop()->as_ValueType();
93 Node* value = vt->field_value_by_offset(field->offset());
94 push_node(bt, value);
95 return;
96 }
97
98 if (is_field == field->is_static()) {
99 // Interpreter will throw java_lang_IncompatibleClassChangeError
100 // Check this before allowing <clinit> methods to access static fields
101 uncommon_trap(Deoptimization::Reason_unhandled,
102 Deoptimization::Action_none);
103 return;
104 }
105
106 if (!is_field && !field_holder->is_initialized()) {
107 if (!static_field_ok_in_clinit(field, method())) {
108 uncommon_trap(Deoptimization::Reason_uninitialized,
109 Deoptimization::Action_reinterpret,
110 NULL, "!static_field_ok_in_clinit");
111 return;
112 }
113 }
114
115 // Deoptimize on putfield writes to call site target field.
116 if (!is_get && field->is_call_site_target()) {
117 uncommon_trap(Deoptimization::Reason_unhandled,
118 Deoptimization::Action_reinterpret,
119 NULL, "put to call site target field");
120 return;
121 }
122
123 assert(field->will_link(method(), bc()), "getfield: typeflow responsibility");
124
125 // Note: We do not check for an unloaded field type here any more.
126
127 // Generate code for the object pointer.
128 Node* obj;
129 if (is_field) {
130 int obj_depth = is_get ? 0 : field->type()->size();
131 obj = null_check(peek(obj_depth));
132 // Compile-time detect of null-exception?
133 if (stopped()) return;
134
135 #ifdef ASSERT
136 const TypeInstPtr *tjp = TypeInstPtr::make(TypePtr::NotNull, iter().get_declared_field_holder());
137 assert(_gvn.type(obj)->higher_equal(tjp), "cast_up is no longer needed");
138 #endif
139
140 if (is_get) {
141 (void) pop(); // pop receiver before getting
142 do_get_xxx(obj, field, is_field);
143 } else {
144 do_put_xxx(obj, field, is_field);
145 (void) pop(); // pop receiver after putting
146 }
147 } else {
148 const TypeInstPtr* tip = TypeInstPtr::make(field_holder->java_mirror());
149 obj = _gvn.makecon(tip);
150 if (is_get) {
151 do_get_xxx(obj, field, is_field);
152 } else {
153 do_put_xxx(obj, field, is_field);
154 }
155 }
156 }
157
158 void Parse::do_get_xxx(Node* obj, ciField* field, bool is_field) {
159 BasicType bt = field->layout_type();
160
161 // Does this field have a constant value? If so, just push the value.
162 if (field->is_constant() &&
163 // Keep consistent with types found by ciTypeFlow: for an
164 // unloaded field type, ciTypeFlow::StateVector::do_getstatic()
165 // speculates the field is null. The code in the rest of this
166 // method does the same. We must not bypass it and use a non
167 // null constant here.
168 (bt != T_OBJECT || field->type()->is_loaded())) {
169 // final or stable field
170 Node* con = make_constant_from_field(field, obj);
171 if (con != NULL) {
172 push_node(field->layout_type(), con);
173 return;
174 }
175 }
176
177 ciType* field_klass = field->type();
178 bool is_vol = field->is_volatile();
179 bool flattened = field->is_flattened();
180
181 // Compute address and memory type.
182 int offset = field->offset_in_bytes();
183 const TypePtr* adr_type = C->alias_type(field)->adr_type();
184 Node *adr = basic_plus_adr(obj, obj, offset);
185
186 // Build the resultant type of the load
187 const Type *type;
188
189 bool must_assert_null = false;
190 if (bt == T_OBJECT || bt == T_VALUETYPE) {
191 if (!field->type()->is_loaded()) {
192 type = TypeInstPtr::BOTTOM;
193 must_assert_null = true;
194 } else if (field->is_static_constant()) {
195 // This can happen if the constant oop is non-perm.
196 ciObject* con = field->constant_value().as_object();
197 // Do not "join" in the previous type; it doesn't add value,
198 // and may yield a vacuous result if the field is of interface type.
199 if (con->is_null_object()) {
200 type = TypePtr::NULL_PTR;
201 } else {
202 type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
203 }
204 assert(type != NULL, "field singleton type must be consistent");
205 } else {
206 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
207 if (bt == T_VALUETYPE && !flattened) {
208 // A non-flattened value type field may be NULL
209 bool maybe_null = true;
210 if (field->is_static()) {
211 // Check if static field is already initialized
212 ciInstance* mirror = field->holder()->java_mirror();
213 ciObject* val = mirror->field_value(field).as_object();
214 if (!val->is_null_object()) {
215 maybe_null = false;
216 }
217 }
218 if (maybe_null) {
219 type = type->is_valuetypeptr()->cast_to_ptr_type(TypePtr::BotPTR);
220 }
221 }
222 }
223 } else {
224 type = Type::get_const_basic_type(bt);
225 }
226 if (support_IRIW_for_not_multiple_copy_atomic_cpu && field->is_volatile()) {
227 insert_mem_bar(Op_MemBarVolatile); // StoreLoad barrier
228 }
229
230 // Build the load.
231 //
232 MemNode::MemOrd mo = is_vol ? MemNode::acquire : MemNode::unordered;
233 bool needs_atomic_access = is_vol || AlwaysAtomicAccesses;
234 Node* ld = NULL;
235 if (flattened) {
236 // Load flattened value type
237 ld = ValueTypeNode::make(this, field_klass->as_value_klass(), obj, obj, field->holder(), offset);
238 } else {
239 ld = make_load(NULL, adr, type, bt, adr_type, mo, LoadNode::DependsOnlyOnTest, needs_atomic_access);
240 }
241
242 // Adjust Java stack
243 if (type2size[bt] == 1)
244 push(ld);
245 else
246 push_pair(ld);
247
248 if (must_assert_null) {
249 // Do not take a trap here. It's possible that the program
250 // will never load the field's class, and will happily see
251 // null values in this field forever. Don't stumble into a
252 // trap for such a program, or we might get a long series
253 // of useless recompilations. (Or, we might load a class
254 // which should not be loaded.) If we ever see a non-null
255 // value, we will then trap and recompile. (The trap will
256 // not need to mention the class index, since the class will
257 // already have been loaded if we ever see a non-null value.)
258 // uncommon_trap(iter().get_field_signature_index());
259 if (PrintOpto && (Verbose || WizardMode)) {
260 method()->print_name(); tty->print_cr(" asserting nullness of field at bci: %d", bci());
261 }
262 if (C->log() != NULL) {
263 C->log()->elem("assert_null reason='field' klass='%d'",
264 C->log()->identify(field->type()));
265 }
266 // If there is going to be a trap, put it at the next bytecode:
267 set_bci(iter().next_bci());
268 null_assert(peek());
269 set_bci(iter().cur_bci()); // put it back
270 }
271
272 // If reference is volatile, prevent following memory ops from
273 // floating up past the volatile read. Also prevents commoning
274 // another volatile read.
275 if (field->is_volatile()) {
276 // Memory barrier includes bogus read of value to force load BEFORE membar
277 insert_mem_bar(Op_MemBarAcquire, ld);
278 }
279 }
280
281 void Parse::do_put_xxx(Node* obj, ciField* field, bool is_field) {
282 bool is_vol = field->is_volatile();
283 bool is_flattened = field->is_flattened();
284 // If reference is volatile, prevent following memory ops from
285 // floating down past the volatile write. Also prevents commoning
286 // another volatile read.
287 if (is_vol) insert_mem_bar(Op_MemBarRelease);
288
289 // Compute address and memory type.
290 int offset = field->offset_in_bytes();
291 const TypePtr* adr_type = C->alias_type(field)->adr_type();
292 Node* adr = basic_plus_adr(obj, obj, offset);
293 BasicType bt = field->layout_type();
294 // Value to be stored
295 Node* val = type2size[bt] == 1 ? pop() : pop_pair();
296 // Round doubles before storing
297 if (bt == T_DOUBLE) val = dstore_rounding(val);
298
299 // Conservatively release stores of object references.
300 const MemNode::MemOrd mo =
301 is_vol ?
302 // Volatile fields need releasing stores.
303 MemNode::release :
304 // Non-volatile fields also need releasing stores if they hold an
305 // object reference, because the object reference might point to
306 // a freshly created object.
307 StoreNode::release_if_reference(bt);
308
309 // Store the value.
310 if (bt == T_OBJECT || bt == T_VALUETYPE) {
311 const TypeOopPtr* field_type;
312 if (!field->type()->is_loaded()) {
313 field_type = TypeInstPtr::BOTTOM;
314 } else {
315 field_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
316 }
317 if (is_flattened) {
318 // Store flattened value type to a non-static field
319 assert(bt == T_VALUETYPE, "flattening is only supported for value type fields");
320 val->as_ValueType()->store_flattened(this, obj, obj, field->holder(), offset);
321 } else {
322 if (bt == T_VALUETYPE) {
323 field_type = field_type->cast_to_ptr_type(TypePtr::BotPTR)->is_oopptr();
324 }
325 store_oop_to_object(control(), obj, adr, adr_type, val, field_type, bt, mo);
326 }
327 } else {
328 bool needs_atomic_access = is_vol || AlwaysAtomicAccesses;
329 store_to_memory(control(), adr, val, bt, adr_type, mo, needs_atomic_access);
330 }
331
332 // If reference is volatile, prevent following volatiles ops from
333 // floating up before the volatile write.
334 if (is_vol) {
335 // If not multiple copy atomic, we do the MemBarVolatile before the load.
336 if (!support_IRIW_for_not_multiple_copy_atomic_cpu) {
337 insert_mem_bar(Op_MemBarVolatile); // Use fat membar
338 }
339 // Remember we wrote a volatile field.
340 // For not multiple copy atomic cpu (ppc64) a barrier should be issued
341 // in constructors which have such stores. See do_exits() in parse1.cpp.
342 if (is_field) {
343 set_wrote_volatile(true);
344 }
345 }
346
347 if (is_field) {
348 set_wrote_fields(true);
349 }
350
351 // If the field is final, the rules of Java say we are in <init> or <clinit>.
352 // Note the presence of writes to final non-static fields, so that we
353 // can insert a memory barrier later on to keep the writes from floating
354 // out of the constructor.
355 // Any method can write a @Stable field; insert memory barriers after those also.
356 if (is_field && (field->is_final() || field->is_stable())) {
357 if (field->is_final()) {
358 set_wrote_final(true);
359 }
360 if (field->is_stable()) {
361 set_wrote_stable(true);
362 }
363
364 // Preserve allocation ptr to create precedent edge to it in membar
365 // generated on exit from constructor.
366 // Can't bind stable with its allocation, only record allocation for final field.
367 if (field->is_final() && AllocateNode::Ideal_allocation(obj, &_gvn) != NULL) {
368 set_alloc_with_final(obj);
369 }
370 }
371 }
372
373 //=============================================================================
374
375 void Parse::do_newarray() {
376 bool will_link;
377 ciKlass* klass = iter().get_klass(will_link);
378
379 // Uncommon Trap when class that array contains is not loaded
380 // we need the loaded class for the rest of graph; do not
381 // initialize the container class (see Java spec)!!!
382 assert(will_link, "newarray: typeflow responsibility");
383
384 ciArrayKlass* array_klass = ciArrayKlass::make(klass);
385 // Check that array_klass object is loaded
386 if (!array_klass->is_loaded()) {
387 // Generate uncommon_trap for unloaded array_class
388 uncommon_trap(Deoptimization::Reason_unloaded,
389 Deoptimization::Action_reinterpret,
390 array_klass);
391 return;
392 } else if (array_klass->element_klass() != NULL &&
393 array_klass->element_klass()->is_valuetype() &&
394 !array_klass->element_klass()->as_value_klass()->is_initialized()) {
395 uncommon_trap(Deoptimization::Reason_uninitialized,
396 Deoptimization::Action_reinterpret,
397 NULL);
398 return;
399 }
400
401 kill_dead_locals();
402
403 const TypeKlassPtr* array_klass_type = TypeKlassPtr::make(array_klass);
404 Node* count_val = pop();
405 Node* obj = new_array(makecon(array_klass_type), count_val, 1);
406 push(obj);
407 }
408
409
410 void Parse::do_newarray(BasicType elem_type) {
411 kill_dead_locals();
412
413 Node* count_val = pop();
414 const TypeKlassPtr* array_klass = TypeKlassPtr::make(ciTypeArrayKlass::make(elem_type));
415 Node* obj = new_array(makecon(array_klass), count_val, 1);
416 // Push resultant oop onto stack
417 push(obj);
418 }
419
420 // Expand simple expressions like new int[3][5] and new Object[2][nonConLen].
421 // Also handle the degenerate 1-dimensional case of anewarray.
422 Node* Parse::expand_multianewarray(ciArrayKlass* array_klass, Node* *lengths, int ndimensions, int nargs) {
423 Node* length = lengths[0];
424 assert(length != NULL, "");
425 Node* array = new_array(makecon(TypeKlassPtr::make(array_klass)), length, nargs);
426 if (ndimensions > 1) {
427 jint length_con = find_int_con(length, -1);
428 guarantee(length_con >= 0, "non-constant multianewarray");
429 ciArrayKlass* array_klass_1 = array_klass->as_obj_array_klass()->element_klass()->as_array_klass();
430 const TypePtr* adr_type = TypeAryPtr::OOPS;
431 const TypeOopPtr* elemtype = _gvn.type(array)->is_aryptr()->elem()->make_oopptr();
432 const intptr_t header = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
433 for (jint i = 0; i < length_con; i++) {
434 Node* elem = expand_multianewarray(array_klass_1, &lengths[1], ndimensions-1, nargs);
435 intptr_t offset = header + ((intptr_t)i << LogBytesPerHeapOop);
436 Node* eaddr = basic_plus_adr(array, offset);
437 store_oop_to_array(control(), array, eaddr, adr_type, elem, elemtype, T_OBJECT, MemNode::unordered);
438 }
439 }
440 return array;
441 }
442
443 void Parse::do_multianewarray() {
444 int ndimensions = iter().get_dimensions();
445
446 // the m-dimensional array
447 bool will_link;
448 ciArrayKlass* array_klass = iter().get_klass(will_link)->as_array_klass();
449 assert(will_link, "multianewarray: typeflow responsibility");
450
451 // Note: Array classes are always initialized; no is_initialized check.
452
453 kill_dead_locals();
454
455 // get the lengths from the stack (first dimension is on top)
456 Node** length = NEW_RESOURCE_ARRAY(Node*, ndimensions + 1);
457 length[ndimensions] = NULL; // terminating null for make_runtime_call
458 int j;
459 for (j = ndimensions-1; j >= 0 ; j--) length[j] = pop();
460
461 // The original expression was of this form: new T[length0][length1]...
462 // It is often the case that the lengths are small (except the last).
463 // If that happens, use the fast 1-d creator a constant number of times.
464 const jint expand_limit = MIN2((jint)MultiArrayExpandLimit, 100);
465 jint expand_count = 1; // count of allocations in the expansion
466 jint expand_fanout = 1; // running total fanout
467 for (j = 0; j < ndimensions-1; j++) {
468 jint dim_con = find_int_con(length[j], -1);
469 expand_fanout *= dim_con;
470 expand_count += expand_fanout; // count the level-J sub-arrays
471 if (dim_con <= 0
472 || dim_con > expand_limit
473 || expand_count > expand_limit) {
474 expand_count = 0;
475 break;
476 }
477 }
478
479 // Can use multianewarray instead of [a]newarray if only one dimension,
480 // or if all non-final dimensions are small constants.
481 if (ndimensions == 1 || (1 <= expand_count && expand_count <= expand_limit)) {
482 Node* obj = NULL;
483 // Set the original stack and the reexecute bit for the interpreter
484 // to reexecute the multianewarray bytecode if deoptimization happens.
485 // Do it unconditionally even for one dimension multianewarray.
486 // Note: the reexecute bit will be set in GraphKit::add_safepoint_edges()
487 // when AllocateArray node for newarray is created.
488 { PreserveReexecuteState preexecs(this);
489 inc_sp(ndimensions);
490 // Pass 0 as nargs since uncommon trap code does not need to restore stack.
491 obj = expand_multianewarray(array_klass, &length[0], ndimensions, 0);
492 } //original reexecute and sp are set back here
493 push(obj);
494 return;
495 }
496
497 address fun = NULL;
498 switch (ndimensions) {
499 case 1: ShouldNotReachHere(); break;
500 case 2: fun = OptoRuntime::multianewarray2_Java(); break;
501 case 3: fun = OptoRuntime::multianewarray3_Java(); break;
502 case 4: fun = OptoRuntime::multianewarray4_Java(); break;
503 case 5: fun = OptoRuntime::multianewarray5_Java(); break;
504 };
505 Node* c = NULL;
506
507 if (fun != NULL) {
508 c = make_runtime_call(RC_NO_LEAF | RC_NO_IO,
509 OptoRuntime::multianewarray_Type(ndimensions),
510 fun, NULL, TypeRawPtr::BOTTOM,
511 makecon(TypeKlassPtr::make(array_klass)),
512 length[0], length[1], length[2],
513 (ndimensions > 2) ? length[3] : NULL,
514 (ndimensions > 3) ? length[4] : NULL);
515 } else {
516 // Create a java array for dimension sizes
517 Node* dims = NULL;
518 { PreserveReexecuteState preexecs(this);
519 inc_sp(ndimensions);
520 Node* dims_array_klass = makecon(TypeKlassPtr::make(ciArrayKlass::make(ciType::make(T_INT))));
521 dims = new_array(dims_array_klass, intcon(ndimensions), 0);
522
523 // Fill-in it with values
524 for (j = 0; j < ndimensions; j++) {
525 Node *dims_elem = array_element_address(dims, intcon(j), T_INT);
526 store_to_memory(control(), dims_elem, length[j], T_INT, TypeAryPtr::INTS, MemNode::unordered);
527 }
528 }
529
530 c = make_runtime_call(RC_NO_LEAF | RC_NO_IO,
531 OptoRuntime::multianewarrayN_Type(),
532 OptoRuntime::multianewarrayN_Java(), NULL, TypeRawPtr::BOTTOM,
533 makecon(TypeKlassPtr::make(array_klass)),
534 dims);
535 }
536 make_slow_call_ex(c, env()->Throwable_klass(), false);
537
538 Node* res = _gvn.transform(new ProjNode(c, TypeFunc::Parms));
539
540 const Type* type = TypeOopPtr::make_from_klass_raw(array_klass);
541
542 // Improve the type: We know it's not null, exact, and of a given length.
543 type = type->is_ptr()->cast_to_ptr_type(TypePtr::NotNull);
544 type = type->is_aryptr()->cast_to_exactness(true);
545
546 const TypeInt* ltype = _gvn.find_int_type(length[0]);
547 if (ltype != NULL)
548 type = type->is_aryptr()->cast_to_size(ltype);
549
550 // We cannot sharpen the nested sub-arrays, since the top level is mutable.
551
552 Node* cast = _gvn.transform( new CheckCastPPNode(control(), res, type) );
553 push(cast);
554
555 // Possible improvements:
556 // - Make a fast path for small multi-arrays. (W/ implicit init. loops.)
557 // - Issue CastII against length[*] values, to TypeInt::POS.
558 }
559
560 void Parse::do_vbox() {
561 // Obtain target type (from bytecodes)
562 bool will_link;
563 ciKlass* target_klass = iter().get_klass(will_link);
564 guarantee(will_link, "vbox: Value-capable class must be loaded");
565 guarantee(target_klass->is_instance_klass(), "vbox: Target class must be an instance type");
566
567 // Obtain source type
568 ValueTypeNode* vt = peek()->as_ValueType();
569 const TypeValueType* src_type = gvn().type(vt)->isa_valuetype();
570 guarantee(src_type != NULL, "vbox: Source type must not be null");
571 ciValueKlass* src_vk = src_type->value_klass();
572 guarantee(src_vk != NULL && src_vk->is_loaded() && src_vk->exact_klass(),
573 "vbox: Source class must be a value type and must be loaded and exact");
574
575 kill_dead_locals();
576
577 ciInstanceKlass* target_vcc_klass = target_klass->as_instance_klass();
578 ciInstanceKlass* src_vcc_klass = src_vk->vcc_klass();
579
580 // TODO: Extend type check below if (and once) value type class hierarchies become available.
581 // (incl. extension to support dynamic type checks).
582 if (!src_vcc_klass->equals(target_vcc_klass)) {
583 builtin_throw(Deoptimization::Reason_class_check);
584 guarantee(stopped(), "A ClassCastException must be always thrown on this path");
585 return;
586 }
587 guarantee(src_vk->is_valuetype(), "vbox: Target DVT must be a value type");
588 pop();
589
590 // Create new object
591 Node* kls = makecon(TypeKlassPtr::make(target_vcc_klass));
592 Node* obj = new_instance(kls);
593
594 // Store all field values to the newly created object.
595 // The code below relies on the assumption that the VCC has the
596 // same memory layout as the derived value type.
597 // TODO: Once the layout of the two is not the same, update code below.
598 vt->as_ValueType()->store(this, obj, obj, target_vcc_klass);
599
600 // Push the new object onto the stack
601 push(obj);
602 }
603
604 void Parse::do_vunbox() {
605 kill_dead_locals();
606
607 // Check if the VCC instance is null.
608 Node* not_null_obj = null_check(peek());
609
610 // Value determined to be null at compile time
611 if (stopped()) {
612 return;
613 }
614
615 // Obtain target type (from bytecodes)
616 bool will_link;
617 ciKlass* target_klass = iter().get_klass(will_link);
618 guarantee(will_link, "vunbox: Derived value type must be loaded");
619 guarantee(target_klass->is_instance_klass(), "vunbox: Target class must be an instance type");
620
621 // Obtain source type
622 const TypeOopPtr* source_type = gvn().type(not_null_obj)->isa_oopptr();
623 guarantee(source_type != NULL && source_type->klass() != NULL &&
624 source_type->klass()->is_instance_klass() && source_type->klass()->is_loaded(),
625 "vunbox: Source class must be an instance type and must be loaded");
626
627 ciInstanceKlass* target_dvt_klass = target_klass->as_instance_klass();
628 ciInstanceKlass* target_vcc_klass = target_dvt_klass->vcc_klass();
629
630 // Check if the class of the source is a subclass of the value-capable class
631 // corresponding to the target.
632 // TOOD: Implement profiling of vunbox bytecodes to enable type speculation.
633 if (target_vcc_klass == NULL || !source_type->klass()->is_subclass_of(target_vcc_klass)) {
634 // It is obvious at compile-time that source and target are unrelated.
635 builtin_throw(Deoptimization::Reason_class_check);
636 guarantee(stopped(), "A ClassCastException must be always thrown on this path");
637 return;
638 }
639 guarantee(target_dvt_klass->is_valuetype(), "vunbox: Target DVT must be a value type");
640
641 if (!target_vcc_klass->equals(source_type->klass()) || !source_type->klass_is_exact()) {
642 Node* exact_obj = not_null_obj;
643 Node* slow_ctl = type_check_receiver(exact_obj, target_vcc_klass, 1.0, &exact_obj);
644 {
645 PreserveJVMState pjvms(this);
646 set_control(slow_ctl);
647 builtin_throw(Deoptimization::Reason_class_check);
648 }
649 replace_in_map(not_null_obj, exact_obj);
650 not_null_obj = exact_obj;
651 }
652
653 // Remove object from the top of the stack
654 pop();
655
656 // Create a value type node with the corresponding type
657 ciValueKlass* vk = target_dvt_klass->as_value_klass();
658 Node* vt = ValueTypeNode::make(this, vk, not_null_obj, not_null_obj, target_vcc_klass, vk->first_field_offset());
659
660 // Push the value type onto the stack
661 push(vt);
662 }