| /* |
| * Copyright (c) 2004, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "asm/macroAssembler.hpp" |
| #include "asm/codeBuffer.hpp" |
| #include "memory/metaspaceShared.hpp" |
| |
| // Generate the self-patching vtable method: |
| // |
| // This method will be called (as any other Klass virtual method) with |
| // the Klass itself as the first argument. Example: |
| // |
| // oop obj; |
| // int size = obj->klass()->oop_size(this); |
| // |
| // for which the virtual method call is Klass::oop_size(); |
| // |
| // The dummy method is called with the Klass object as the first |
| // operand, and an object as the second argument. |
| // |
| |
| //===================================================================== |
| |
| // All of the dummy methods in the vtable are essentially identical, |
| // differing only by an ordinal constant, and they bear no relationship |
| // to the original method which the caller intended. Also, there needs |
| // to be 'vtbl_list_size' instances of the vtable in order to |
| // differentiate between the 'vtable_list_size' original Klass objects. |
| |
| #define __ masm-> |
| |
| void MetaspaceShared::generate_vtable_methods(void** vtbl_list, |
| void** vtable, |
| char** md_top, |
| char* md_end, |
| char** mc_top, |
| char* mc_end) { |
| |
| intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*); |
| *(intptr_t *)(*md_top) = vtable_bytes; |
| *md_top += sizeof(intptr_t); |
| void** dummy_vtable = (void**)*md_top; |
| *vtable = dummy_vtable; |
| *md_top += vtable_bytes; |
| |
| // Get ready to generate dummy methods. |
| |
| CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top); |
| MacroAssembler* masm = new MacroAssembler(&cb); |
| |
| Label common_code; |
| for (int i = 0; i < vtbl_list_size; ++i) { |
| for (int j = 0; j < num_virtuals; ++j) { |
| dummy_vtable[num_virtuals * i + j] = (void*)masm->pc(); |
| |
| // Load eax with a value indicating vtable/offset pair. |
| // -- bits[ 7..0] (8 bits) which virtual method in table? |
| // -- bits[12..8] (5 bits) which virtual method table? |
| // -- must fit in 13-bit instruction immediate field. |
| __ movl(rax, (i << 8) + j); |
| __ jmp(common_code); |
| } |
| } |
| |
| __ bind(common_code); |
| |
| // Expecting to be called with "thiscall" convections -- the arguments |
| // are on the stack and the "this" pointer is in c_rarg0. In addition, rax |
| // was set (above) to the offset of the method in the table. |
| |
| __ push(c_rarg1); // save & free register |
| __ push(c_rarg0); // save "this" |
| __ mov(c_rarg0, rax); |
| __ shrptr(c_rarg0, 8); // isolate vtable identifier. |
| __ shlptr(c_rarg0, LogBytesPerWord); |
| __ lea(c_rarg1, ExternalAddress((address)vtbl_list)); // ptr to correct vtable list. |
| __ addptr(c_rarg1, c_rarg0); // ptr to list entry. |
| __ movptr(c_rarg1, Address(c_rarg1, 0)); // get correct vtable address. |
| __ pop(c_rarg0); // restore "this" |
| __ movptr(Address(c_rarg0, 0), c_rarg1); // update vtable pointer. |
| |
| __ andptr(rax, 0x00ff); // isolate vtable method index |
| __ shlptr(rax, LogBytesPerWord); |
| __ addptr(rax, c_rarg1); // address of real method pointer. |
| __ pop(c_rarg1); // restore register. |
| __ movptr(rax, Address(rax, 0)); // get real method pointer. |
| __ jmp(rax); // jump to the real method. |
| |
| __ flush(); |
| |
| *mc_top = (char*)__ pc(); |
| } |
