Mercurial > hg > truffle
comparison src/share/vm/c1/c1_CodeStubs.hpp @ 6615:09aad8452938
7190310: Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops
Summary: In C2 add software membar after load from Reference.referent field to prevent commoning of loads across safepoint since GC can change its value. In C1 always generate Reference.get() intrinsic.
Reviewed-by: roland, twisti, dholmes, johnc
| author | kvn |
|---|---|
| date | Mon, 20 Aug 2012 09:58:58 -0700 |
| parents | e1162778c1c8 |
| children | da91efe96a93 |
comparison
equal
deleted
inserted
replaced
| 6614:006050192a5a | 6615:09aad8452938 |
|---|---|
| 572 #ifndef PRODUCT | 572 #ifndef PRODUCT |
| 573 virtual void print_name(outputStream* out) const { out->print("G1PreBarrierStub"); } | 573 virtual void print_name(outputStream* out) const { out->print("G1PreBarrierStub"); } |
| 574 #endif // PRODUCT | 574 #endif // PRODUCT |
| 575 }; | 575 }; |
| 576 | 576 |
| 577 // This G1 barrier code stub is used in Unsafe.getObject. | |
| 578 // It generates a sequence of guards around the SATB | |
| 579 // barrier code that are used to detect when we have | |
| 580 // the referent field of a Reference object. | |
| 581 // The first check is assumed to have been generated | |
| 582 // in the code generated for Unsafe.getObject(). | |
| 583 | |
| 584 class G1UnsafeGetObjSATBBarrierStub: public CodeStub { | |
| 585 private: | |
| 586 LIR_Opr _val; | |
| 587 LIR_Opr _src; | |
| 588 | |
| 589 LIR_Opr _tmp; | |
| 590 LIR_Opr _thread; | |
| 591 | |
| 592 bool _gen_src_check; | |
| 593 | |
| 594 public: | |
| 595 // A G1 barrier that is guarded by generated guards that determine whether | |
| 596 // val (which is the result of Unsafe.getObject() should be recorded in an | |
| 597 // SATB log buffer. We could be reading the referent field of a Reference object | |
| 598 // using Unsafe.getObject() and we need to record the referent. | |
| 599 // | |
| 600 // * val is the operand returned by the unsafe.getObject routine. | |
| 601 // * src is the base object | |
| 602 // * tmp is a temp used to load the klass of src, and then reference type | |
| 603 // * thread is the thread object. | |
| 604 | |
| 605 G1UnsafeGetObjSATBBarrierStub(LIR_Opr val, LIR_Opr src, | |
| 606 LIR_Opr tmp, LIR_Opr thread, | |
| 607 bool gen_src_check) : | |
| 608 _val(val), _src(src), | |
| 609 _tmp(tmp), _thread(thread), | |
| 610 _gen_src_check(gen_src_check) | |
| 611 { | |
| 612 assert(_val->is_register(), "should have already been loaded"); | |
| 613 assert(_src->is_register(), "should have already been loaded"); | |
| 614 | |
| 615 assert(_tmp->is_register(), "should be a temporary register"); | |
| 616 } | |
| 617 | |
| 618 LIR_Opr val() const { return _val; } | |
| 619 LIR_Opr src() const { return _src; } | |
| 620 | |
| 621 LIR_Opr tmp() const { return _tmp; } | |
| 622 LIR_Opr thread() const { return _thread; } | |
| 623 | |
| 624 bool gen_src_check() const { return _gen_src_check; } | |
| 625 | |
| 626 virtual void emit_code(LIR_Assembler* e); | |
| 627 | |
| 628 virtual void visit(LIR_OpVisitState* visitor) { | |
| 629 visitor->do_slow_case(); | |
| 630 visitor->do_input(_val); | |
| 631 visitor->do_input(_src); | |
| 632 visitor->do_input(_thread); | |
| 633 | |
| 634 visitor->do_temp(_tmp); | |
| 635 } | |
| 636 | |
| 637 #ifndef PRODUCT | |
| 638 virtual void print_name(outputStream* out) const { out->print("G1UnsafeGetObjSATBBarrierStub"); } | |
| 639 #endif // PRODUCT | |
| 640 }; | |
| 641 | |
| 642 class G1PostBarrierStub: public CodeStub { | 577 class G1PostBarrierStub: public CodeStub { |
| 643 private: | 578 private: |
| 644 LIR_Opr _addr; | 579 LIR_Opr _addr; |
| 645 LIR_Opr _new_val; | 580 LIR_Opr _new_val; |
| 646 | 581 |