#ifdef USE_PRAGMA_IDENT_SRC
#pragma ident "@(#)vtableStubs_i486.cpp	1.51 07/05/17 15:47:16 JVM"
#endif
/*
 * Copyright 1997-2006 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/_vtableStubs_i486.cpp.incl"

// 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

// used by compiler only; may use only caller saved registers eax, ebx, ecx.
// edx holds first int arg, esi, edi, ebp are callee-save & must be preserved.
// Leave receiver in ecx; required behavior when +OptoArgsInRegisters
// is modifed to put first oop in ecx.
//
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);
  ResourceMark rm;
  CodeBuffer cb(s->entry_point(), i486_code_length);
  MacroAssembler* masm = new MacroAssembler(&cb);

#ifndef PRODUCT
  if (CountCompiledCalls) __ increment(Address((int)SharedRuntime::nof_megamorphic_calls_addr(), relocInfo::none));
#endif /* PRODUCT */

  // get receiver (need to skip return address on top of stack)
  assert(VtableStub::receiver_location() == ecx->as_VMReg(), "receiver expected in ecx");

  // get receiver klass
  address npe_addr = __ pc();
  __ movl(eax, Address(ecx, oopDesc::klass_offset_in_bytes()));
  // compute entry offset (in words)
  int entry_offset = instanceKlass::vtable_start_offset() + vtable_index*vtableEntry::size();
#ifndef PRODUCT
  if (DebugVtables) { 
    Label L;
    // check offset vs vtable length
    __ cmpl(Address(eax, instanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size());
    __ jcc(Assembler::greater, L);
    __ movl(ebx, vtable_index);
    __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), ecx, ebx);
    __ bind(L);
  }
#endif // PRODUCT

  const Register method = ebx;

  // load methodOop and target address
  __ movl(method, Address(eax, entry_offset*wordSize + vtableEntry::method_offset_in_bytes()));
  if (DebugVtables) {
    Label L;
    __ cmpl(method, NULL_WORD);
    __ jcc(Assembler::equal, L);
    __ cmpl(Address(method, methodOopDesc::from_compiled_offset()), NULL_WORD);
    __ jcc(Assembler::notZero, L);
    __ stop("Vtable entry is NULL");
    __ bind(L);
  }

  // eax: receiver klass 
  // method (ebx): methodOop
  // ecx: receiver
  address ame_addr = __ pc();
  __ jmp( Address(method, methodOopDesc::from_compiled_offset()));

  masm->flush();
  s->set_exception_points(npe_addr, ame_addr);
  return s;
}


VtableStub* VtableStubs::create_itable_stub(int vtable_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, vtable_index);
  ResourceMark rm;
  CodeBuffer cb(s->entry_point(), i486_code_length);
  MacroAssembler* masm = new MacroAssembler(&cb);
  
  // Entry arguments:
  //  eax: Interface
  //  ecx: Receiver
  
#ifndef PRODUCT
  if (CountCompiledCalls) __ increment(Address((int)SharedRuntime::nof_megamorphic_calls_addr(), relocInfo::none));
#endif /* PRODUCT */
  // get receiver (need to skip return address on top of stack)
 
  assert(VtableStub::receiver_location() == ecx->as_VMReg(), "receiver expected in ecx");
  
  // get receiver klass (also an implicit null-check)
  address npe_addr = __ pc();
  __ movl(ebx, Address(ecx, oopDesc::klass_offset_in_bytes()));    

  __ movl(esi, ebx);   // Save klass in free register    
  // Most registers are in use, so save a few
  __ pushl(edx);
  // compute itable entry offset (in words)  
  const int base = instanceKlass::vtable_start_offset() * wordSize;    
  assert(vtableEntry::size() * wordSize == 4, "adjust the scaling in the code below");
  __ movl(edx, Address(ebx, instanceKlass::vtable_length_offset() * wordSize)); // Get length of vtable
  __ leal(ebx, Address(ebx, edx, Address::times_4, base));
  if (HeapWordsPerLong > 1) {
    // Round up to align_object_offset boundary
    __ round_to(ebx, BytesPerLong);
  }

  Label hit, next, entry;
  
  __ jmp(entry);

  __ bind(next);
  __ addl(ebx, itableOffsetEntry::size() * wordSize);
  
  __ bind(entry);

#ifdef ASSERT
    // Check that the entry is non-null
  if (DebugVtables) { 
    Label L;
    __ pushl(ebx);
    __ movl(ebx, Address(ebx, itableOffsetEntry::interface_offset_in_bytes()));
    __ testl(ebx, ebx);
    __ jcc(Assembler::notZero, L);
    __ stop("null entry point found in itable's offset table");
    __ bind(L);
    __ popl(ebx);    
  }
#endif
  __ cmpl(eax, Address(ebx, itableOffsetEntry::interface_offset_in_bytes()));
  __ jcc(Assembler::notEqual, next);    
  
  // We found a hit, move offset into ebx
  __ movl(edx, Address(ebx, itableOffsetEntry::offset_offset_in_bytes()));

  // Compute itableMethodEntry.  
  const int method_offset = (itableMethodEntry::size() * wordSize * vtable_index) + itableMethodEntry::method_offset_in_bytes();
  
  // Get methodOop and entrypoint for compiler    
  const Register method = ebx;
  __ movl(method, Address(esi, edx, Address::times_1, method_offset));  

  // Restore saved register, before possible trap.
  __ popl(edx);

  // method (ebx): methodOop
  // ecx: receiver
  
#ifdef ASSERT
  if (DebugVtables) {
      Label L1;
      __ cmpl(method, NULL_WORD);
      __ jcc(Assembler::equal, L1);
      __ cmpl(Address(method, methodOopDesc::from_compiled_offset()), NULL_WORD);
      __ jcc(Assembler::notZero, L1);
      __ stop("methodOop is null");
      __ bind(L1);
    }
#endif // ASSERT

  address ame_addr = __ pc();
  __ jmp(Address(method, methodOopDesc::from_compiled_offset()));
    
  masm->flush();
  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 ? 140 : 55) + (CountCompiledCalls ? 6 : 0);
  }
}

int VtableStub::pd_code_alignment() {
  return wordSize;
}