Mercurial > hg > truffle
view src/cpu/x86/vm/runtime_x86_32.cpp @ 453:c96030fff130
6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa
author | ysr |
---|---|
date | Thu, 20 Nov 2008 16:56:09 -0800 |
parents | 9ee9cf798b59 |
children | db4caa99ef11 |
line wrap: on
line source
/* * Copyright 1998-2008 Sun Microsystems, Inc. All Rights Reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ #include "incls/_precompiled.incl" #include "incls/_runtime_x86_32.cpp.incl" #define __ masm-> ExceptionBlob* OptoRuntime::_exception_blob; //------------------------------generate_exception_blob--------------------------- // creates exception blob at the end // Using exception blob, this code is jumped from a compiled method. // // Given an exception pc at a call we call into the runtime for the // handler in this method. This handler might merely restore state // (i.e. callee save registers) unwind the frame and jump to the // exception handler for the nmethod if there is no Java level handler // for the nmethod. // // This code is entered with a jmp. // // Arguments: // rax,: exception oop // rdx: exception pc // // Results: // rax,: exception oop // rdx: exception pc in caller or ??? // destination: exception handler of caller // // Note: the exception pc MUST be at a call (precise debug information) // Only register rax, rdx, rcx are not callee saved. // void OptoRuntime::generate_exception_blob() { // Capture info about frame layout enum layout { thread_off, // last_java_sp // The frame sender code expects that rbp will be in the "natural" place and // will override any oopMap setting for it. We must therefore force the layout // so that it agrees with the frame sender code. rbp_off, return_off, // slot for return address framesize }; // allocate space for the code ResourceMark rm; // setup code generation tools CodeBuffer buffer("exception_blob", 512, 512); MacroAssembler* masm = new MacroAssembler(&buffer); OopMapSet *oop_maps = new OopMapSet(); address start = __ pc(); __ push(rdx); __ subptr(rsp, return_off * wordSize); // Prolog! // rbp, location is implicitly known __ movptr(Address(rsp,rbp_off *wordSize), rbp); // Store exception in Thread object. We cannot pass any arguments to the // handle_exception call, since we do not want to make any assumption // about the size of the frame where the exception happened in. __ get_thread(rcx); __ movptr(Address(rcx, JavaThread::exception_oop_offset()), rax); __ movptr(Address(rcx, JavaThread::exception_pc_offset()), rdx); // This call does all the hard work. It checks if an exception handler // exists in the method. // If so, it returns the handler address. // If not, it prepares for stack-unwinding, restoring the callee-save // registers of the frame being removed. // __ movptr(Address(rsp, thread_off * wordSize), rcx); // Thread is first argument __ set_last_Java_frame(rcx, noreg, noreg, NULL); __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C))); // No registers to map, rbp is known implicitly oop_maps->add_gc_map( __ pc() - start, new OopMap( framesize, 0 )); __ get_thread(rcx); __ reset_last_Java_frame(rcx, false, false); // Restore callee-saved registers __ movptr(rbp, Address(rsp, rbp_off * wordSize)); __ addptr(rsp, return_off * wordSize); // Epilog! __ pop(rdx); // Exception pc // rax,: exception handler for given <exception oop/exception pc> // We have a handler in rax, (could be deopt blob) // rdx - throwing pc, deopt blob will need it. __ push(rax); // rcx contains handler address __ get_thread(rcx); // TLS // Get the exception __ movptr(rax, Address(rcx, JavaThread::exception_oop_offset())); // Get the exception pc in case we are deoptimized __ movptr(rdx, Address(rcx, JavaThread::exception_pc_offset())); #ifdef ASSERT __ movptr(Address(rcx, JavaThread::exception_handler_pc_offset()), (int32_t)NULL_WORD); __ movptr(Address(rcx, JavaThread::exception_pc_offset()), (int32_t)NULL_WORD); #endif // Clear the exception oop so GC no longer processes it as a root. __ movptr(Address(rcx, JavaThread::exception_oop_offset()), (int32_t)NULL_WORD); __ pop(rcx); // rax,: exception oop // rcx: exception handler // rdx: exception pc __ jmp (rcx); // ------------- // make sure all code is generated masm->flush(); _exception_blob = ExceptionBlob::create(&buffer, oop_maps, framesize); }