/*

 * Copyright (c) 1997, 2016, 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/compiledICHolder.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, Klass::vtable_length_offset()), 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: CompiledICHolder

  //  rcx: Receiver

#ifndef PRODUCT

  if (CountCompiledCalls) {

    __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));

  }

#endif /* PRODUCT */

  // 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 recv_klass_reg     = rsi;

  const Register holder_klass_reg   = rax; // declaring interface klass (DECC)

  const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)

  const Register temp_reg           = rdi;

  const Register icholder_reg = rax;

  __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));

  __ movptr(holder_klass_reg,   Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));

  Label L_no_such_interface;

  // get receiver klass (also an implicit null-check)

  address npe_addr = __ pc();

  assert(VtableStub::receiver_location() ==  rcx->as_VMReg(), "receiver expected in  rcx");

  __ load_klass(recv_klass_reg, rcx);

  // Receiver subtype check against REFC.

  // Destroys recv_klass_reg value.

  __ lookup_interface_method(// inputs: rec. class, interface

                             recv_klass_reg, resolved_klass_reg, noreg,

                             // outputs:  scan temp. reg1, scan temp. reg2

                             recv_klass_reg, temp_reg,

                             L_no_such_interface,

                             /*return_method=*/false);

  // Get selected method from declaring class and itable index

  const Register method = rbx;

  __ load_klass(recv_klass_reg, rcx); // restore recv_klass_reg

  __ lookup_interface_method(// inputs: rec. class, interface, itable index

                             recv_klass_reg, holder_klass_reg, itable_index,

                             // outputs: method, scan temp. reg

                             method, temp_reg,

                             L_no_such_interface);

  // 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(L_no_such_interface);

  __ 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 : 110) + (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;

}