1 /* 2 * Copyright (c) 1998, 2010, 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 26 #include "incls/_precompiled.incl" 27 #include "incls/_runtime_x86_32.cpp.incl" 28 29 #define __ masm-> 30 31 ExceptionBlob* OptoRuntime::_exception_blob; 32 33 //------------------------------generate_exception_blob--------------------------- 34 // creates exception blob at the end 35 // Using exception blob, this code is jumped from a compiled method. 36 // 37 // Given an exception pc at a call we call into the runtime for the 38 // handler in this method. This handler might merely restore state 39 // (i.e. callee save registers) unwind the frame and jump to the 40 // exception handler for the nmethod if there is no Java level handler 41 // for the nmethod. 42 // 43 // This code is entered with a jmp. 44 // 45 // Arguments: 46 // rax: exception oop 47 // rdx: exception pc 48 // 49 // Results: 50 // rax: exception oop 51 // rdx: exception pc in caller or ??? 52 // destination: exception handler of caller 53 // 54 // Note: the exception pc MUST be at a call (precise debug information) 55 // Only register rax, rdx, rcx are not callee saved. 56 // 57 58 void OptoRuntime::generate_exception_blob() { 59 60 // Capture info about frame layout 61 enum layout { 62 thread_off, // last_java_sp 63 // The frame sender code expects that rbp will be in the "natural" place and 64 // will override any oopMap setting for it. We must therefore force the layout 65 // so that it agrees with the frame sender code. 66 rbp_off, 67 return_off, // slot for return address 68 framesize 69 }; 70 71 // allocate space for the code 72 ResourceMark rm; 73 // setup code generation tools 74 CodeBuffer buffer("exception_blob", 512, 512); 75 MacroAssembler* masm = new MacroAssembler(&buffer); 76 77 OopMapSet *oop_maps = new OopMapSet(); 78 79 address start = __ pc(); 80 81 __ push(rdx); 82 __ subptr(rsp, return_off * wordSize); // Prolog! 83 84 // rbp, location is implicitly known 85 __ movptr(Address(rsp,rbp_off *wordSize), rbp); 86 87 // Store exception in Thread object. We cannot pass any arguments to the 88 // handle_exception call, since we do not want to make any assumption 89 // about the size of the frame where the exception happened in. 90 __ get_thread(rcx); 91 __ movptr(Address(rcx, JavaThread::exception_oop_offset()), rax); 92 __ movptr(Address(rcx, JavaThread::exception_pc_offset()), rdx); 93 94 // This call does all the hard work. It checks if an exception handler 95 // exists in the method. 96 // If so, it returns the handler address. 97 // If not, it prepares for stack-unwinding, restoring the callee-save 98 // registers of the frame being removed. 99 // 100 __ movptr(Address(rsp, thread_off * wordSize), rcx); // Thread is first argument 101 __ set_last_Java_frame(rcx, noreg, noreg, NULL); 102 103 __ call(RuntimeAddress(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C))); 104 105 // No registers to map, rbp is known implicitly 106 oop_maps->add_gc_map( __ pc() - start, new OopMap( framesize, 0 )); 107 __ get_thread(rcx); 108 __ reset_last_Java_frame(rcx, false, false); 109 110 // Restore callee-saved registers 111 __ movptr(rbp, Address(rsp, rbp_off * wordSize)); 112 113 __ addptr(rsp, return_off * wordSize); // Epilog! 114 __ pop(rdx); // Exception pc 115 116 // rax: exception handler for given <exception oop/exception pc> 117 118 // Restore SP from BP if the exception PC is a MethodHandle call site. 119 __ cmpl(Address(rcx, JavaThread::is_method_handle_return_offset()), 0); 120 __ cmovptr(Assembler::notEqual, rsp, rbp_mh_SP_save); 121 122 // We have a handler in rax, (could be deopt blob) 123 // rdx - throwing pc, deopt blob will need it. 124 125 __ push(rax); 126 127 // Get the exception 128 __ movptr(rax, Address(rcx, JavaThread::exception_oop_offset())); 129 // Get the exception pc in case we are deoptimized 130 __ movptr(rdx, Address(rcx, JavaThread::exception_pc_offset())); 131 #ifdef ASSERT 132 __ movptr(Address(rcx, JavaThread::exception_handler_pc_offset()), NULL_WORD); 133 __ movptr(Address(rcx, JavaThread::exception_pc_offset()), NULL_WORD); 134 #endif 135 // Clear the exception oop so GC no longer processes it as a root. 136 __ movptr(Address(rcx, JavaThread::exception_oop_offset()), NULL_WORD); 137 138 __ pop(rcx); 139 140 // rax: exception oop 141 // rcx: exception handler 142 // rdx: exception pc 143 __ jmp (rcx); 144 145 // ------------- 146 // make sure all code is generated 147 masm->flush(); 148 149 _exception_blob = ExceptionBlob::create(&buffer, oop_maps, framesize); 150 }