Mercurial > hg > graal-compiler
comparison src/share/vm/opto/graphKit.cpp @ 1746:4b29a725c43c
6912064: type profiles need to be exploited more for dynamic language support
Reviewed-by: kvn
author | jrose |
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date | Fri, 20 Aug 2010 23:40:30 -0700 |
parents | 4311f23817fd |
children | 3e8fbc61cee8 |
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1730:f55c4f82ab9d | 1746:4b29a725c43c |
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2449 | 2449 |
2450 return fail; | 2450 return fail; |
2451 } | 2451 } |
2452 | 2452 |
2453 | 2453 |
2454 //------------------------------seems_never_null------------------------------- | |
2455 // Use null_seen information if it is available from the profile. | |
2456 // If we see an unexpected null at a type check we record it and force a | |
2457 // recompile; the offending check will be recompiled to handle NULLs. | |
2458 // If we see several offending BCIs, then all checks in the | |
2459 // method will be recompiled. | |
2460 bool GraphKit::seems_never_null(Node* obj, ciProfileData* data) { | |
2461 if (UncommonNullCast // Cutout for this technique | |
2462 && obj != null() // And not the -Xcomp stupid case? | |
2463 && !too_many_traps(Deoptimization::Reason_null_check) | |
2464 ) { | |
2465 if (data == NULL) | |
2466 // Edge case: no mature data. Be optimistic here. | |
2467 return true; | |
2468 // If the profile has not seen a null, assume it won't happen. | |
2469 assert(java_bc() == Bytecodes::_checkcast || | |
2470 java_bc() == Bytecodes::_instanceof || | |
2471 java_bc() == Bytecodes::_aastore, "MDO must collect null_seen bit here"); | |
2472 return !data->as_BitData()->null_seen(); | |
2473 } | |
2474 return false; | |
2475 } | |
2476 | |
2477 //------------------------maybe_cast_profiled_receiver------------------------- | |
2478 // If the profile has seen exactly one type, narrow to exactly that type. | |
2479 // Subsequent type checks will always fold up. | |
2480 Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj, | |
2481 ciProfileData* data, | |
2482 ciKlass* require_klass) { | |
2483 if (!UseTypeProfile || !TypeProfileCasts) return NULL; | |
2484 if (data == NULL) return NULL; | |
2485 | |
2486 // Make sure we haven't already deoptimized from this tactic. | |
2487 if (too_many_traps(Deoptimization::Reason_class_check)) | |
2488 return NULL; | |
2489 | |
2490 // (No, this isn't a call, but it's enough like a virtual call | |
2491 // to use the same ciMethod accessor to get the profile info...) | |
2492 ciCallProfile profile = method()->call_profile_at_bci(bci()); | |
2493 if (profile.count() >= 0 && // no cast failures here | |
2494 profile.has_receiver(0) && | |
2495 profile.morphism() == 1) { | |
2496 ciKlass* exact_kls = profile.receiver(0); | |
2497 if (require_klass == NULL || | |
2498 static_subtype_check(require_klass, exact_kls) == SSC_always_true) { | |
2499 // If we narrow the type to match what the type profile sees, | |
2500 // we can then remove the rest of the cast. | |
2501 // This is a win, even if the exact_kls is very specific, | |
2502 // because downstream operations, such as method calls, | |
2503 // will often benefit from the sharper type. | |
2504 Node* exact_obj = not_null_obj; // will get updated in place... | |
2505 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0, | |
2506 &exact_obj); | |
2507 { PreserveJVMState pjvms(this); | |
2508 set_control(slow_ctl); | |
2509 uncommon_trap(Deoptimization::Reason_class_check, | |
2510 Deoptimization::Action_maybe_recompile); | |
2511 } | |
2512 replace_in_map(not_null_obj, exact_obj); | |
2513 return exact_obj; | |
2514 } | |
2515 // assert(ssc == SSC_always_true)... except maybe the profile lied to us. | |
2516 } | |
2517 | |
2518 return NULL; | |
2519 } | |
2520 | |
2521 | |
2454 //-------------------------------gen_instanceof-------------------------------- | 2522 //-------------------------------gen_instanceof-------------------------------- |
2455 // Generate an instance-of idiom. Used by both the instance-of bytecode | 2523 // Generate an instance-of idiom. Used by both the instance-of bytecode |
2456 // and the reflective instance-of call. | 2524 // and the reflective instance-of call. |
2457 Node* GraphKit::gen_instanceof( Node *subobj, Node* superklass ) { | 2525 Node* GraphKit::gen_instanceof(Node* obj, Node* superklass) { |
2458 C->set_has_split_ifs(true); // Has chance for split-if optimization | 2526 kill_dead_locals(); // Benefit all the uncommon traps |
2459 assert( !stopped(), "dead parse path should be checked in callers" ); | 2527 assert( !stopped(), "dead parse path should be checked in callers" ); |
2460 assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()), | 2528 assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()), |
2461 "must check for not-null not-dead klass in callers"); | 2529 "must check for not-null not-dead klass in callers"); |
2462 | 2530 |
2463 // Make the merge point | 2531 // Make the merge point |
2464 enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT }; | 2532 enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT }; |
2465 RegionNode* region = new(C, PATH_LIMIT) RegionNode(PATH_LIMIT); | 2533 RegionNode* region = new(C, PATH_LIMIT) RegionNode(PATH_LIMIT); |
2466 Node* phi = new(C, PATH_LIMIT) PhiNode(region, TypeInt::BOOL); | 2534 Node* phi = new(C, PATH_LIMIT) PhiNode(region, TypeInt::BOOL); |
2467 C->set_has_split_ifs(true); // Has chance for split-if optimization | 2535 C->set_has_split_ifs(true); // Has chance for split-if optimization |
2468 | 2536 |
2537 ciProfileData* data = NULL; | |
2538 if (java_bc() == Bytecodes::_instanceof) { // Only for the bytecode | |
2539 data = method()->method_data()->bci_to_data(bci()); | |
2540 } | |
2541 bool never_see_null = (ProfileDynamicTypes // aggressive use of profile | |
2542 && seems_never_null(obj, data)); | |
2543 | |
2469 // Null check; get casted pointer; set region slot 3 | 2544 // Null check; get casted pointer; set region slot 3 |
2470 Node* null_ctl = top(); | 2545 Node* null_ctl = top(); |
2471 Node* not_null_obj = null_check_oop(subobj, &null_ctl); | 2546 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null); |
2472 | 2547 |
2473 // If not_null_obj is dead, only null-path is taken | 2548 // If not_null_obj is dead, only null-path is taken |
2474 if (stopped()) { // Doing instance-of on a NULL? | 2549 if (stopped()) { // Doing instance-of on a NULL? |
2475 set_control(null_ctl); | 2550 set_control(null_ctl); |
2476 return intcon(0); | 2551 return intcon(0); |
2477 } | 2552 } |
2478 region->init_req(_null_path, null_ctl); | 2553 region->init_req(_null_path, null_ctl); |
2479 phi ->init_req(_null_path, intcon(0)); // Set null path value | 2554 phi ->init_req(_null_path, intcon(0)); // Set null path value |
2555 if (null_ctl == top()) { | |
2556 // Do this eagerly, so that pattern matches like is_diamond_phi | |
2557 // will work even during parsing. | |
2558 assert(_null_path == PATH_LIMIT-1, "delete last"); | |
2559 region->del_req(_null_path); | |
2560 phi ->del_req(_null_path); | |
2561 } | |
2562 | |
2563 if (ProfileDynamicTypes && data != NULL) { | |
2564 Node* cast_obj = maybe_cast_profiled_receiver(not_null_obj, data, NULL); | |
2565 if (stopped()) { // Profile disagrees with this path. | |
2566 set_control(null_ctl); // Null is the only remaining possibility. | |
2567 return intcon(0); | |
2568 } | |
2569 if (cast_obj != NULL) | |
2570 not_null_obj = cast_obj; | |
2571 } | |
2480 | 2572 |
2481 // Load the object's klass | 2573 // Load the object's klass |
2482 Node* obj_klass = load_object_klass(not_null_obj); | 2574 Node* obj_klass = load_object_klass(not_null_obj); |
2483 | 2575 |
2484 // Generate the subtype check | 2576 // Generate the subtype check |
2544 RegionNode* region = new (C, PATH_LIMIT) RegionNode(PATH_LIMIT); | 2636 RegionNode* region = new (C, PATH_LIMIT) RegionNode(PATH_LIMIT); |
2545 Node* phi = new (C, PATH_LIMIT) PhiNode(region, toop); | 2637 Node* phi = new (C, PATH_LIMIT) PhiNode(region, toop); |
2546 C->set_has_split_ifs(true); // Has chance for split-if optimization | 2638 C->set_has_split_ifs(true); // Has chance for split-if optimization |
2547 | 2639 |
2548 // Use null-cast information if it is available | 2640 // Use null-cast information if it is available |
2549 bool never_see_null = false; | 2641 bool never_see_null = ((failure_control == NULL) // regular case only |
2550 // If we see an unexpected null at a check-cast we record it and force a | 2642 && seems_never_null(obj, data)); |
2551 // recompile; the offending check-cast will be compiled to handle NULLs. | |
2552 // If we see several offending BCIs, then all checkcasts in the | |
2553 // method will be compiled to handle NULLs. | |
2554 if (UncommonNullCast // Cutout for this technique | |
2555 && failure_control == NULL // regular case | |
2556 && obj != null() // And not the -Xcomp stupid case? | |
2557 && !too_many_traps(Deoptimization::Reason_null_check)) { | |
2558 // Finally, check the "null_seen" bit from the interpreter. | |
2559 if (data == NULL || !data->as_BitData()->null_seen()) { | |
2560 never_see_null = true; | |
2561 } | |
2562 } | |
2563 | 2643 |
2564 // Null check; get casted pointer; set region slot 3 | 2644 // Null check; get casted pointer; set region slot 3 |
2565 Node* null_ctl = top(); | 2645 Node* null_ctl = top(); |
2566 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null); | 2646 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null); |
2567 | 2647 |
2570 set_control(null_ctl); | 2650 set_control(null_ctl); |
2571 return null(); | 2651 return null(); |
2572 } | 2652 } |
2573 region->init_req(_null_path, null_ctl); | 2653 region->init_req(_null_path, null_ctl); |
2574 phi ->init_req(_null_path, null()); // Set null path value | 2654 phi ->init_req(_null_path, null()); // Set null path value |
2575 | 2655 if (null_ctl == top()) { |
2576 Node* cast_obj = NULL; // the casted version of the object | 2656 // Do this eagerly, so that pattern matches like is_diamond_phi |
2577 | 2657 // will work even during parsing. |
2578 // If the profile has seen exactly one type, narrow to that type. | 2658 assert(_null_path == PATH_LIMIT-1, "delete last"); |
2579 // (The subsequent subtype check will always fold up.) | 2659 region->del_req(_null_path); |
2580 if (UseTypeProfile && TypeProfileCasts && data != NULL && | 2660 phi ->del_req(_null_path); |
2661 } | |
2662 | |
2663 Node* cast_obj = NULL; | |
2664 if (data != NULL && | |
2581 // Counter has never been decremented (due to cast failure). | 2665 // Counter has never been decremented (due to cast failure). |
2582 // ...This is a reasonable thing to expect. It is true of | 2666 // ...This is a reasonable thing to expect. It is true of |
2583 // all casts inserted by javac to implement generic types. | 2667 // all casts inserted by javac to implement generic types. |
2584 data->as_CounterData()->count() >= 0 && | 2668 data->as_CounterData()->count() >= 0) { |
2585 !too_many_traps(Deoptimization::Reason_class_check)) { | 2669 cast_obj = maybe_cast_profiled_receiver(not_null_obj, data, tk->klass()); |
2586 // (No, this isn't a call, but it's enough like a virtual call | 2670 if (cast_obj != NULL) { |
2587 // to use the same ciMethod accessor to get the profile info...) | 2671 if (failure_control != NULL) // failure is now impossible |
2588 ciCallProfile profile = method()->call_profile_at_bci(bci()); | 2672 (*failure_control) = top(); |
2589 if (profile.count() >= 0 && // no cast failures here | 2673 // adjust the type of the phi to the exact klass: |
2590 profile.has_receiver(0) && | 2674 phi->raise_bottom_type(_gvn.type(cast_obj)->meet(TypePtr::NULL_PTR)); |
2591 profile.morphism() == 1) { | |
2592 ciKlass* exact_kls = profile.receiver(0); | |
2593 int ssc = static_subtype_check(tk->klass(), exact_kls); | |
2594 if (ssc == SSC_always_true) { | |
2595 // If we narrow the type to match what the type profile sees, | |
2596 // we can then remove the rest of the cast. | |
2597 // This is a win, even if the exact_kls is very specific, | |
2598 // because downstream operations, such as method calls, | |
2599 // will often benefit from the sharper type. | |
2600 Node* exact_obj = not_null_obj; // will get updated in place... | |
2601 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0, | |
2602 &exact_obj); | |
2603 { PreserveJVMState pjvms(this); | |
2604 set_control(slow_ctl); | |
2605 uncommon_trap(Deoptimization::Reason_class_check, | |
2606 Deoptimization::Action_maybe_recompile); | |
2607 } | |
2608 if (failure_control != NULL) // failure is now impossible | |
2609 (*failure_control) = top(); | |
2610 replace_in_map(not_null_obj, exact_obj); | |
2611 // adjust the type of the phi to the exact klass: | |
2612 phi->raise_bottom_type(_gvn.type(exact_obj)->meet(TypePtr::NULL_PTR)); | |
2613 cast_obj = exact_obj; | |
2614 } | |
2615 // assert(cast_obj != NULL)... except maybe the profile lied to us. | |
2616 } | 2675 } |
2617 } | 2676 } |
2618 | 2677 |
2619 if (cast_obj == NULL) { | 2678 if (cast_obj == NULL) { |
2620 // Load the object's klass | 2679 // Load the object's klass |