1 /* 2 * Copyright 2004-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 # include "incls/_precompiled.incl" 26 # include "incls/_dump_x86_32.cpp.incl" 27 28 29 30 // Generate the self-patching vtable method: 31 // 32 // This method will be called (as any other Klass virtual method) with 33 // the Klass itself as the first argument. Example: 34 // 35 // oop obj; 36 // int size = obj->klass()->klass_part()->oop_size(this); 37 // 38 // for which the virtual method call is Klass::oop_size(); 39 // 40 // The dummy method is called with the Klass object as the first 41 // operand, and an object as the second argument. 42 // 43 44 //===================================================================== 45 46 // All of the dummy methods in the vtable are essentially identical, 47 // differing only by an ordinal constant, and they bear no releationship 48 // to the original method which the caller intended. Also, there needs 49 // to be 'vtbl_list_size' instances of the vtable in order to 50 // differentiate between the 'vtable_list_size' original Klass objects. 51 52 #define __ masm-> 53 54 void CompactingPermGenGen::generate_vtable_methods(void** vtbl_list, 55 void** vtable, 56 char** md_top, 57 char* md_end, 58 char** mc_top, 59 char* mc_end) { 60 61 intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*); 62 *(intptr_t *)(*md_top) = vtable_bytes; 63 *md_top += sizeof(intptr_t); 64 void** dummy_vtable = (void**)*md_top; 65 *vtable = dummy_vtable; 66 *md_top += vtable_bytes; 67 68 // Get ready to generate dummy methods. 69 70 CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top); 71 MacroAssembler* masm = new MacroAssembler(&cb); 72 73 Label common_code; 74 for (int i = 0; i < vtbl_list_size; ++i) { 75 for (int j = 0; j < num_virtuals; ++j) { 76 dummy_vtable[num_virtuals * i + j] = (void*)masm->pc(); 77 78 // Load rax, with a value indicating vtable/offset pair. 79 // -- bits[ 7..0] (8 bits) which virtual method in table? 80 // -- bits[12..8] (5 bits) which virtual method table? 81 // -- must fit in 13-bit instruction immediate field. 82 __ movl(rax, (i << 8) + j); 83 __ jmp(common_code); 84 } 85 } 86 87 __ bind(common_code); 88 89 #ifdef WIN32 90 // Expecting to be called with "thiscall" conventions -- the arguments 91 // are on the stack, except that the "this" pointer is in rcx. 92 #else 93 // Expecting to be called with Unix conventions -- the arguments 94 // are on the stack, including the "this" pointer. 95 #endif 96 97 // In addition, rax was set (above) to the offset of the method in the 98 // table. 99 100 #ifdef WIN32 101 __ push(rcx); // save "this" 102 #endif 103 __ mov(rcx, rax); 104 __ shrptr(rcx, 8); // isolate vtable identifier. 105 __ shlptr(rcx, LogBytesPerWord); 106 Address index(noreg, rcx, Address::times_1); 107 ExternalAddress vtbl((address)vtbl_list); 108 __ movptr(rdx, ArrayAddress(vtbl, index)); // get correct vtable address. 109 #ifdef WIN32 110 __ pop(rcx); // restore "this" 111 #else 112 __ movptr(rcx, Address(rsp, BytesPerWord)); // fetch "this" 113 #endif 114 __ movptr(Address(rcx, 0), rdx); // update vtable pointer. 115 116 __ andptr(rax, 0x00ff); // isolate vtable method index 117 __ shlptr(rax, LogBytesPerWord); 118 __ addptr(rax, rdx); // address of real method pointer. 119 __ jmp(Address(rax, 0)); // get real method pointer. 120 121 __ flush(); 122 123 *mc_top = (char*)__ pc(); 124 }