1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/src/cpu/x86/vm/metaspaceShared_x86_64.cpp Wed Apr 27 01:25:04 2016 +0800 1.3 @@ -0,0 +1,114 @@ 1.4 +/* 1.5 + * Copyright (c) 2004, 2012, Oracle and/or its affiliates. All rights reserved. 1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 1.7 + * 1.8 + * This code is free software; you can redistribute it and/or modify it 1.9 + * under the terms of the GNU General Public License version 2 only, as 1.10 + * published by the Free Software Foundation. 1.11 + * 1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT 1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1.15 + * version 2 for more details (a copy is included in the LICENSE file that 1.16 + * accompanied this code). 1.17 + * 1.18 + * You should have received a copy of the GNU General Public License version 1.19 + * 2 along with this work; if not, write to the Free Software Foundation, 1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 1.21 + * 1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 1.23 + * or visit www.oracle.com if you need additional information or have any 1.24 + * questions. 1.25 + * 1.26 + */ 1.27 + 1.28 +#include "precompiled.hpp" 1.29 +#include "asm/macroAssembler.hpp" 1.30 +#include "asm/codeBuffer.hpp" 1.31 +#include "memory/metaspaceShared.hpp" 1.32 + 1.33 +// Generate the self-patching vtable method: 1.34 +// 1.35 +// This method will be called (as any other Klass virtual method) with 1.36 +// the Klass itself as the first argument. Example: 1.37 +// 1.38 +// oop obj; 1.39 +// int size = obj->klass()->oop_size(this); 1.40 +// 1.41 +// for which the virtual method call is Klass::oop_size(); 1.42 +// 1.43 +// The dummy method is called with the Klass object as the first 1.44 +// operand, and an object as the second argument. 1.45 +// 1.46 + 1.47 +//===================================================================== 1.48 + 1.49 +// All of the dummy methods in the vtable are essentially identical, 1.50 +// differing only by an ordinal constant, and they bear no relationship 1.51 +// to the original method which the caller intended. Also, there needs 1.52 +// to be 'vtbl_list_size' instances of the vtable in order to 1.53 +// differentiate between the 'vtable_list_size' original Klass objects. 1.54 + 1.55 +#define __ masm-> 1.56 + 1.57 +void MetaspaceShared::generate_vtable_methods(void** vtbl_list, 1.58 + void** vtable, 1.59 + char** md_top, 1.60 + char* md_end, 1.61 + char** mc_top, 1.62 + char* mc_end) { 1.63 + 1.64 + intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*); 1.65 + *(intptr_t *)(*md_top) = vtable_bytes; 1.66 + *md_top += sizeof(intptr_t); 1.67 + void** dummy_vtable = (void**)*md_top; 1.68 + *vtable = dummy_vtable; 1.69 + *md_top += vtable_bytes; 1.70 + 1.71 + // Get ready to generate dummy methods. 1.72 + 1.73 + CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top); 1.74 + MacroAssembler* masm = new MacroAssembler(&cb); 1.75 + 1.76 + Label common_code; 1.77 + for (int i = 0; i < vtbl_list_size; ++i) { 1.78 + for (int j = 0; j < num_virtuals; ++j) { 1.79 + dummy_vtable[num_virtuals * i + j] = (void*)masm->pc(); 1.80 + 1.81 + // Load eax with a value indicating vtable/offset pair. 1.82 + // -- bits[ 7..0] (8 bits) which virtual method in table? 1.83 + // -- bits[12..8] (5 bits) which virtual method table? 1.84 + // -- must fit in 13-bit instruction immediate field. 1.85 + __ movl(rax, (i << 8) + j); 1.86 + __ jmp(common_code); 1.87 + } 1.88 + } 1.89 + 1.90 + __ bind(common_code); 1.91 + 1.92 + // Expecting to be called with "thiscall" convections -- the arguments 1.93 + // are on the stack and the "this" pointer is in c_rarg0. In addition, rax 1.94 + // was set (above) to the offset of the method in the table. 1.95 + 1.96 + __ push(c_rarg1); // save & free register 1.97 + __ push(c_rarg0); // save "this" 1.98 + __ mov(c_rarg0, rax); 1.99 + __ shrptr(c_rarg0, 8); // isolate vtable identifier. 1.100 + __ shlptr(c_rarg0, LogBytesPerWord); 1.101 + __ lea(c_rarg1, ExternalAddress((address)vtbl_list)); // ptr to correct vtable list. 1.102 + __ addptr(c_rarg1, c_rarg0); // ptr to list entry. 1.103 + __ movptr(c_rarg1, Address(c_rarg1, 0)); // get correct vtable address. 1.104 + __ pop(c_rarg0); // restore "this" 1.105 + __ movptr(Address(c_rarg0, 0), c_rarg1); // update vtable pointer. 1.106 + 1.107 + __ andptr(rax, 0x00ff); // isolate vtable method index 1.108 + __ shlptr(rax, LogBytesPerWord); 1.109 + __ addptr(rax, c_rarg1); // address of real method pointer. 1.110 + __ pop(c_rarg1); // restore register. 1.111 + __ movptr(rax, Address(rax, 0)); // get real method pointer. 1.112 + __ jmp(rax); // jump to the real method. 1.113 + 1.114 + __ flush(); 1.115 + 1.116 + *mc_top = (char*)__ pc(); 1.117 +}