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/*
* Copyright 2004-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
# include "incls/_precompiled.incl"
# include "incls/_dump_x86_32.cpp.incl"
// 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()->klass_part()->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 releationship
// 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 CompactingPermGenGen::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 rax, 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);
#ifdef WIN32
// Expecting to be called with "thiscall" conventions -- the arguments
// are on the stack, except that the "this" pointer is in rcx.
#else
// Expecting to be called with Unix conventions -- the arguments
// are on the stack, including the "this" pointer.
#endif
// In addition, rax was set (above) to the offset of the method in the
// table.
#ifdef WIN32
__ push(rcx); // save "this"
#endif
__ mov(rcx, rax);
__ shrptr(rcx, 8); // isolate vtable identifier.
__ shlptr(rcx, LogBytesPerWord);
Address index(noreg, rcx, Address::times_1);
ExternalAddress vtbl((address)vtbl_list);
__ movptr(rdx, ArrayAddress(vtbl, index)); // get correct vtable address.
#ifdef WIN32
__ pop(rcx); // restore "this"
#else
__ movptr(rcx, Address(rsp, BytesPerWord)); // fetch "this"
#endif
__ movptr(Address(rcx, 0), rdx); // update vtable pointer.
__ andptr(rax, 0x00ff); // isolate vtable method index
__ shlptr(rax, LogBytesPerWord);
__ addptr(rax, rdx); // address of real method pointer.
__ jmp(Address(rax, 0)); // get real method pointer.
__ flush();
*mc_top = (char*)__ pc();
}
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