/*
* Copyright (c) 1997, 2014, 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 "code/vtableStubs.hpp"
#include "interp_masm_x86.hpp"
#include "memory/resourceArea.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/klassVtable.hpp"
#include "runtime/sharedRuntime.hpp"
#include "vmreg_x86.inline.hpp"
#ifdef COMPILER2
#include "opto/runtime.hpp"
#endif
// machine-dependent part of VtableStubs: create VtableStub of correct size and
// initialize its code
#define __ masm->
#ifndef PRODUCT
extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
#endif
// These stubs are used by the compiler only.
// Argument registers, which must be preserved:
// rcx - receiver (always first argument)
// rdx - second argument (if any)
// Other registers that might be usable:
// rax - inline cache register (is interface for itable stub)
// rbx - method (used when calling out to interpreter)
// Available now, but may become callee-save at some point:
// rsi, rdi
// Note that rax and rdx are also used for return values.
//
VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
const int i486_code_length = VtableStub::pd_code_size_limit(true);
VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index);
// Can be NULL if there is no free space in the code cache.
if (s == NULL) {
return NULL;
}
ResourceMark rm;
CodeBuffer cb(s->entry_point(), i486_code_length);
MacroAssembler* masm = new MacroAssembler(&cb);
#ifndef PRODUCT
if (CountCompiledCalls) {
__ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
}
#endif /* PRODUCT */
// get receiver (need to skip return address on top of stack)
assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
// get receiver klass
address npe_addr = __ pc();
__ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
#ifndef PRODUCT
if (DebugVtables) {
Label L;
// check offset vs vtable length
__ cmpl(Address(rax, InstanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size());
__ jcc(Assembler::greater, L);
__ movl(rbx, vtable_index);
__ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
__ bind(L);
}
#endif // PRODUCT
const Register method = rbx;
// load Method* and target address
__ lookup_virtual_method(rax, vtable_index, method);
if (DebugVtables) {
Label L;
__ cmpptr(method, (int32_t)NULL_WORD);
__ jcc(Assembler::equal, L);
__ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
__ jcc(Assembler::notZero, L);
__ stop("Vtable entry is NULL");
__ bind(L);
}
// rax,: receiver klass
// method (rbx): Method*
// rcx: receiver
address ame_addr = __ pc();
__ jmp( Address(method, Method::from_compiled_offset()));
masm->flush();
if (PrintMiscellaneous && (WizardMode || Verbose)) {
tty->print_cr("vtable #%d at " PTR_FORMAT "[%d] left over: %d",
vtable_index, p2i(s->entry_point()),
(int)(s->code_end() - s->entry_point()),
(int)(s->code_end() - __ pc()));
}
guarantee(__ pc() <= s->code_end(), "overflowed buffer");
// shut the door on sizing bugs
int slop = 3; // 32-bit offset is this much larger than an 8-bit one
assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
s->set_exception_points(npe_addr, ame_addr);
return s;
}
VtableStub* VtableStubs::create_itable_stub(int itable_index) {
// Note well: pd_code_size_limit is the absolute minimum we can get away with. If you
// add code here, bump the code stub size returned by pd_code_size_limit!
const int i486_code_length = VtableStub::pd_code_size_limit(false);
VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);
// Can be NULL if there is no free space in the code cache.
if (s == NULL) {
return NULL;
}
ResourceMark rm;
CodeBuffer cb(s->entry_point(), i486_code_length);
MacroAssembler* masm = new MacroAssembler(&cb);
// Entry arguments:
// rax,: Interface
// rcx: Receiver
#ifndef PRODUCT
if (CountCompiledCalls) {
__ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
}
#endif /* PRODUCT */
// get receiver (need to skip return address on top of stack)
assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
// get receiver klass (also an implicit null-check)
address npe_addr = __ pc();
__ movptr(rsi, Address(rcx, oopDesc::klass_offset_in_bytes()));
// Most registers are in use; we'll use rax, rbx, rsi, rdi
// (If we need to make rsi, rdi callee-save, do a push/pop here.)
const Register method = rbx;
Label throw_icce;
// Get Method* and entrypoint for compiler
__ lookup_interface_method(// inputs: rec. class, interface, itable index
rsi, rax, itable_index,
// outputs: method, scan temp. reg
method, rdi,
throw_icce);
// method (rbx): Method*
// rcx: receiver
#ifdef ASSERT
if (DebugVtables) {
Label L1;
__ cmpptr(method, (int32_t)NULL_WORD);
__ jcc(Assembler::equal, L1);
__ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
__ jcc(Assembler::notZero, L1);
__ stop("Method* is null");
__ bind(L1);
}
#endif // ASSERT
address ame_addr = __ pc();
__ jmp(Address(method, Method::from_compiled_offset()));
__ bind(throw_icce);
__ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
masm->flush();
if (PrintMiscellaneous && (WizardMode || Verbose)) {
tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d",
itable_index, p2i(s->entry_point()),
(int)(s->code_end() - s->entry_point()),
(int)(s->code_end() - __ pc()));
}
guarantee(__ pc() <= s->code_end(), "overflowed buffer");
// shut the door on sizing bugs
int slop = 3; // 32-bit offset is this much larger than an 8-bit one
assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
s->set_exception_points(npe_addr, ame_addr);
return s;
}
int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
if (is_vtable_stub) {
// Vtable stub size
return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);
} else {
// Itable stub size
return (DebugVtables ? 256 : 66) + (CountCompiledCalls ? 6 : 0);
}
// In order to tune these parameters, run the JVM with VM options
// +PrintMiscellaneous and +WizardMode to see information about
// actual itable stubs. Look for lines like this:
// itable #1 at 0x5551212[65] left over: 3
// Reduce the constants so that the "left over" number is >=3
// for the common cases.
// Do not aim at a left-over number of zero, because a
// large vtable or itable index (> 16) will require a 32-bit
// immediate displacement instead of an 8-bit one.
//
// The JVM98 app. _202_jess has a megamorphic interface call.
// The itable code looks like this:
// Decoding VtableStub itbl[1]@1
// mov 0x4(%ecx),%esi
// mov 0xe8(%esi),%edi
// lea 0x130(%esi,%edi,4),%edi
// add $0x7,%edi
// and $0xfffffff8,%edi
// lea 0x4(%esi),%esi
// mov (%edi),%ebx
// cmp %ebx,%eax
// je success
// loop:
// test %ebx,%ebx
// je throw_icce
// add $0x8,%edi
// mov (%edi),%ebx
// cmp %ebx,%eax
// jne loop
// success:
// mov 0x4(%edi),%edi
// mov (%esi,%edi,1),%ebx
// jmp *0x44(%ebx)
// throw_icce:
// jmp throw_ICCE_entry
}
int VtableStub::pd_code_alignment() {
return wordSize;
}