/*

 * Copyright (c) 2003, 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

VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {

  const int amd64_code_length = VtableStub::pd_code_size_limit(true);

  VtableStub* s = new(amd64_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(), amd64_code_length);

  MacroAssembler* masm = new MacroAssembler(&cb);

#ifndef PRODUCT

  if (CountCompiledCalls) {

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

  }

#endif

  // get receiver (need to skip return address on top of stack)

  assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");

  // Free registers (non-args) are rax, rbx

  // get receiver klass

  address npe_addr = __ pc();

  __ load_klass(rax, j_rarg0);

#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), j_rarg0, rbx);

    __ bind(L);

  }

#endif // PRODUCT

  // load Method* and target address

  const Register method = rbx;

  __ 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

  // rbx: Method*

  // rcx: receiver

  address ame_addr = __ pc();

  __ jmp( Address(rbx, Method::from_compiled_offset()));

  __ 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 amd64_code_length = VtableStub::pd_code_size_limit(false);

  VtableStub* s = new(amd64_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(), amd64_code_length);

  MacroAssembler* masm = new MacroAssembler(&cb);

#ifndef PRODUCT

  if (CountCompiledCalls) {

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

  }

#endif

  // Entry arguments:

  //  rax: Interface

  //  j_rarg0: Receiver

  // Free registers (non-args) are rax (interface), rbx

  // get receiver (need to skip return address on top of stack)

  assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");

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

  address npe_addr = __ pc();

  // Most registers are in use; we'll use rax, rbx, r10, r11

  // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them)

  __ load_klass(r10, j_rarg0);

  // If we take a trap while this arg is on the stack we will not

  // be able to walk the stack properly. This is not an issue except

  // when there are mistakes in this assembly code that could generate

  // a spurious fault. Ask me how I know...

  const Register method = rbx;

  Label throw_icce;

  // Get Method* and entrypoint for compiler

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

                             r10, rax, itable_index,

                             // outputs: method, scan temp. reg

                             method, r11,

                             throw_icce);

  // method (rbx): Method*

  // j_rarg0: receiver

#ifdef ASSERT

  if (DebugVtables) {

    Label L2;

    __ cmpptr(method, (int32_t)NULL_WORD);

    __ jcc(Assembler::equal, L2);

    __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);

    __ jcc(Assembler::notZero, L2);

    __ stop("compiler entrypoint is null");

    __ bind(L2);

  }

#endif // ASSERT

  // rbx: Method*

  // j_rarg0: receiver

  address ame_addr = __ pc();

  __ jmp(Address(method, Method::from_compiled_offset()));

  __ bind(throw_icce);

  __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));

  __ 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 ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +

           (UseCompressedClassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);

  } else {

    // Itable stub size

    return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) +

           (UseCompressedClassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 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[71] 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 (>= 32) 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]@12

  //   mov    0x8(%rsi),%r10

  //   mov    0x198(%r10),%r11d

  //   lea    0x218(%r10,%r11,8),%r11

  //   lea    0x8(%r10),%r10

  //   mov    (%r11),%rbx

  //   cmp    %rbx,%rax

  //   je     success

  // loop:

  //   test   %rbx,%rbx

  //   je     throw_icce

  //   add    $0x10,%r11

  //   mov    (%r11),%rbx

  //   cmp    %rbx,%rax

  //   jne    loop

  // success:

  //   mov    0x8(%r11),%r11d

  //   mov    (%r10,%r11,1),%rbx

  //   jmpq   *0x60(%rbx)

  // throw_icce:

  //   jmpq   throw_ICCE_entry

}

int VtableStub::pd_code_alignment() {

  return wordSize;

}