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comparison src/share/vm/opto/library_call.cpp @ 7422:eb409f2f146e

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8003135: HotSpot inlines and hoists the Thread.currentThread().isInterrupted() out of the loop Summary: Make the load of TLS._osthread._interrupted flag in Thread.isInterrupted(Z)Z intrinsic effectively volatile. Reviewed-by: kvn, jrose
author vlivanov
date Tue, 18 Dec 2012 06:52:00 -0800
parents dd38cfd12c3a
children 620e502e3f47
comparison
equal deleted inserted replaced
7420:18d56ca3e901 7422:eb409f2f146e
2950 // However, if the receiver is not currentThread, we must call the VM, 2950 // However, if the receiver is not currentThread, we must call the VM,
2951 // because there must be some locking done around the operation. 2951 // because there must be some locking done around the operation.
2952 2952
2953 // We only go to the fast case code if we pass two guards. 2953 // We only go to the fast case code if we pass two guards.
2954 // Paths which do not pass are accumulated in the slow_region. 2954 // Paths which do not pass are accumulated in the slow_region.
2955
2956 enum {
2957 no_int_result_path = 1, // t == Thread.current() && !TLS._osthread._interrupted
2958 no_clear_result_path = 2, // t == Thread.current() && TLS._osthread._interrupted && !clear_int
2959 slow_result_path = 3, // slow path: t.isInterrupted(clear_int)
2960 PATH_LIMIT
2961 };
2962
2963 // Ensure that it's not possible to move the load of TLS._osthread._interrupted flag
2964 // out of the function.
2965 insert_mem_bar(Op_MemBarCPUOrder);
2966
2967 RegionNode* result_rgn = new (C) RegionNode(PATH_LIMIT);
2968 PhiNode* result_val = new (C) PhiNode(result_rgn, TypeInt::BOOL);
2969
2955 RegionNode* slow_region = new (C) RegionNode(1); 2970 RegionNode* slow_region = new (C) RegionNode(1);
2956 record_for_igvn(slow_region); 2971 record_for_igvn(slow_region);
2957 RegionNode* result_rgn = new (C) RegionNode(1+3); // fast1, fast2, slow
2958 PhiNode* result_val = new (C) PhiNode(result_rgn, TypeInt::BOOL);
2959 enum { no_int_result_path = 1,
2960 no_clear_result_path = 2,
2961 slow_result_path = 3
2962 };
2963 2972
2964 // (a) Receiving thread must be the current thread. 2973 // (a) Receiving thread must be the current thread.
2965 Node* rec_thr = argument(0); 2974 Node* rec_thr = argument(0);
2966 Node* tls_ptr = NULL; 2975 Node* tls_ptr = NULL;
2967 Node* cur_thr = generate_current_thread(tls_ptr); 2976 Node* cur_thr = generate_current_thread(tls_ptr);
2968 Node* cmp_thr = _gvn.transform( new (C) CmpPNode(cur_thr, rec_thr) ); 2977 Node* cmp_thr = _gvn.transform( new (C) CmpPNode(cur_thr, rec_thr) );
2969 Node* bol_thr = _gvn.transform( new (C) BoolNode(cmp_thr, BoolTest::ne) ); 2978 Node* bol_thr = _gvn.transform( new (C) BoolNode(cmp_thr, BoolTest::ne) );
2970 2979
2971 bool known_current_thread = (_gvn.type(bol_thr) == TypeInt::ZERO); 2980 generate_slow_guard(bol_thr, slow_region);
2972 if (!known_current_thread)
2973 generate_slow_guard(bol_thr, slow_region);
2974 2981
2975 // (b) Interrupt bit on TLS must be false. 2982 // (b) Interrupt bit on TLS must be false.
2976 Node* p = basic_plus_adr(top()/*!oop*/, tls_ptr, in_bytes(JavaThread::osthread_offset())); 2983 Node* p = basic_plus_adr(top()/*!oop*/, tls_ptr, in_bytes(JavaThread::osthread_offset()));
2977 Node* osthread = make_load(NULL, p, TypeRawPtr::NOTNULL, T_ADDRESS); 2984 Node* osthread = make_load(NULL, p, TypeRawPtr::NOTNULL, T_ADDRESS);
2978 p = basic_plus_adr(top()/*!oop*/, osthread, in_bytes(OSThread::interrupted_offset())); 2985 p = basic_plus_adr(top()/*!oop*/, osthread, in_bytes(OSThread::interrupted_offset()));
2986
2979 // Set the control input on the field _interrupted read to prevent it floating up. 2987 // Set the control input on the field _interrupted read to prevent it floating up.
2980 Node* int_bit = make_load(control(), p, TypeInt::BOOL, T_INT); 2988 Node* int_bit = make_load(control(), p, TypeInt::BOOL, T_INT);
2981 Node* cmp_bit = _gvn.transform( new (C) CmpINode(int_bit, intcon(0)) ); 2989 Node* cmp_bit = _gvn.transform( new (C) CmpINode(int_bit, intcon(0)) );
2982 Node* bol_bit = _gvn.transform( new (C) BoolNode(cmp_bit, BoolTest::ne) ); 2990 Node* bol_bit = _gvn.transform( new (C) BoolNode(cmp_bit, BoolTest::ne) );
2983 2991
3018 CallJavaNode* slow_call = generate_method_call(vmIntrinsics::_isInterrupted); 3026 CallJavaNode* slow_call = generate_method_call(vmIntrinsics::_isInterrupted);
3019 3027
3020 Node* slow_val = set_results_for_java_call(slow_call); 3028 Node* slow_val = set_results_for_java_call(slow_call);
3021 // this->control() comes from set_results_for_java_call 3029 // this->control() comes from set_results_for_java_call
3022 3030
3023 // If we know that the result of the slow call will be true, tell the optimizer!
3024 if (known_current_thread) slow_val = intcon(1);
3025
3026 Node* fast_io = slow_call->in(TypeFunc::I_O); 3031 Node* fast_io = slow_call->in(TypeFunc::I_O);
3027 Node* fast_mem = slow_call->in(TypeFunc::Memory); 3032 Node* fast_mem = slow_call->in(TypeFunc::Memory);
3033
3028 // These two phis are pre-filled with copies of of the fast IO and Memory 3034 // These two phis are pre-filled with copies of of the fast IO and Memory
3029 Node* io_phi = PhiNode::make(result_rgn, fast_io, Type::ABIO); 3035 PhiNode* result_mem = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM);
3030 Node* mem_phi = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM); 3036 PhiNode* result_io = PhiNode::make(result_rgn, fast_io, Type::ABIO);
3031 3037
3032 result_rgn->init_req(slow_result_path, control()); 3038 result_rgn->init_req(slow_result_path, control());
3033 io_phi ->init_req(slow_result_path, i_o()); 3039 result_io ->init_req(slow_result_path, i_o());
3034 mem_phi ->init_req(slow_result_path, reset_memory()); 3040 result_mem->init_req(slow_result_path, reset_memory());
3035 result_val->init_req(slow_result_path, slow_val); 3041 result_val->init_req(slow_result_path, slow_val);
3036 3042
3037 set_all_memory( _gvn.transform(mem_phi) ); 3043 set_all_memory(_gvn.transform(result_mem));
3038 set_i_o( _gvn.transform(io_phi) ); 3044 set_i_o( _gvn.transform(result_io));
3039 } 3045 }
3040 3046
3041 C->set_has_split_ifs(true); // Has chance for split-if optimization 3047 C->set_has_split_ifs(true); // Has chance for split-if optimization
3042 set_result(result_rgn, result_val); 3048 set_result(result_rgn, result_val);
3043 return true; 3049 return true;