1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/cpu/x86/vm/metaspaceShared_x86_32.cpp Sat Sep 01 13:25:18 2012 -0400
1.3 @@ -0,0 +1,123 @@
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 "assembler_x86.inline.hpp"
1.30 +#include "memory/metaspaceShared.hpp"
1.31 +
1.32 +// Generate the self-patching vtable method:
1.33 +//
1.34 +// This method will be called (as any other Klass virtual method) with
1.35 +// the Klass itself as the first argument. Example:
1.36 +//
1.37 +// oop obj;
1.38 +// int size = obj->klass()->oop_size(this);
1.39 +//
1.40 +// for which the virtual method call is Klass::oop_size();
1.41 +//
1.42 +// The dummy method is called with the Klass object as the first
1.43 +// operand, and an object as the second argument.
1.44 +//
1.45 +
1.46 +//=====================================================================
1.47 +
1.48 +// All of the dummy methods in the vtable are essentially identical,
1.49 +// differing only by an ordinal constant, and they bear no relationship
1.50 +// to the original method which the caller intended. Also, there needs
1.51 +// to be 'vtbl_list_size' instances of the vtable in order to
1.52 +// differentiate between the 'vtable_list_size' original Klass objects.
1.53 +
1.54 +#define __ masm->
1.55 +
1.56 +void MetaspaceShared::generate_vtable_methods(void** vtbl_list,
1.57 + void** vtable,
1.58 + char** md_top,
1.59 + char* md_end,
1.60 + char** mc_top,
1.61 + char* mc_end) {
1.62 +
1.63 + intptr_t vtable_bytes = (num_virtuals * vtbl_list_size) * sizeof(void*);
1.64 + *(intptr_t *)(*md_top) = vtable_bytes;
1.65 + *md_top += sizeof(intptr_t);
1.66 + void** dummy_vtable = (void**)*md_top;
1.67 + *vtable = dummy_vtable;
1.68 + *md_top += vtable_bytes;
1.69 +
1.70 + // Get ready to generate dummy methods.
1.71 +
1.72 + CodeBuffer cb((unsigned char*)*mc_top, mc_end - *mc_top);
1.73 + MacroAssembler* masm = new MacroAssembler(&cb);
1.74 +
1.75 + Label common_code;
1.76 + for (int i = 0; i < vtbl_list_size; ++i) {
1.77 + for (int j = 0; j < num_virtuals; ++j) {
1.78 + dummy_vtable[num_virtuals * i + j] = (void*)masm->pc();
1.79 +
1.80 + // Load rax, with a value indicating vtable/offset pair.
1.81 + // -- bits[ 7..0] (8 bits) which virtual method in table?
1.82 + // -- bits[12..8] (5 bits) which virtual method table?
1.83 + // -- must fit in 13-bit instruction immediate field.
1.84 + __ movl(rax, (i << 8) + j);
1.85 + __ jmp(common_code);
1.86 + }
1.87 + }
1.88 +
1.89 + __ bind(common_code);
1.90 +
1.91 +#ifdef WIN32
1.92 + // Expecting to be called with "thiscall" conventions -- the arguments
1.93 + // are on the stack, except that the "this" pointer is in rcx.
1.94 +#else
1.95 + // Expecting to be called with Unix conventions -- the arguments
1.96 + // are on the stack, including the "this" pointer.
1.97 +#endif
1.98 +
1.99 + // In addition, rax was set (above) to the offset of the method in the
1.100 + // table.
1.101 +
1.102 +#ifdef WIN32
1.103 + __ push(rcx); // save "this"
1.104 +#endif
1.105 + __ mov(rcx, rax);
1.106 + __ shrptr(rcx, 8); // isolate vtable identifier.
1.107 + __ shlptr(rcx, LogBytesPerWord);
1.108 + Address index(noreg, rcx, Address::times_1);
1.109 + ExternalAddress vtbl((address)vtbl_list);
1.110 + __ movptr(rdx, ArrayAddress(vtbl, index)); // get correct vtable address.
1.111 +#ifdef WIN32
1.112 + __ pop(rcx); // restore "this"
1.113 +#else
1.114 + __ movptr(rcx, Address(rsp, BytesPerWord)); // fetch "this"
1.115 +#endif
1.116 + __ movptr(Address(rcx, 0), rdx); // update vtable pointer.
1.117 +
1.118 + __ andptr(rax, 0x00ff); // isolate vtable method index
1.119 + __ shlptr(rax, LogBytesPerWord);
1.120 + __ addptr(rax, rdx); // address of real method pointer.
1.121 + __ jmp(Address(rax, 0)); // get real method pointer.
1.122 +
1.123 + __ flush();
1.124 +
1.125 + *mc_top = (char*)__ pc();
1.126 +}
