view src/share/vm/opto/multnode.cpp @ 452:00b023ae2d78

6722113: CMS: Incorrect overflow handling during precleaning of Reference lists Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery. Reviewed-by: apetrusenko, jcoomes
author ysr
date Thu, 20 Nov 2008 12:27:41 -0800
parents a61af66fc99e
children c18cbe5936b8
line wrap: on
line source

/*
 * 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/_multnode.cpp.incl"

//=============================================================================
//------------------------------MultiNode--------------------------------------
const RegMask &MultiNode::out_RegMask() const {
  return RegMask::Empty;
}

Node *MultiNode::match( const ProjNode *proj, const Matcher *m ) { return proj->clone(); }

//------------------------------proj_out---------------------------------------
// Get a named projection
ProjNode* MultiNode::proj_out(uint which_proj) const {
  assert(Opcode() != Op_If || which_proj == (uint)true || which_proj == (uint)false, "must be 1 or 0");
  assert(Opcode() != Op_If || outcnt() == 2, "bad if #1");
  for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
    Node *p = fast_out(i);
    if( !p->is_Proj() ) {
      assert(p == this && this->is_Start(), "else must be proj");
      continue;
    }
    ProjNode *proj = p->as_Proj();
    if( proj->_con == which_proj ) {
      assert(Opcode() != Op_If || proj->Opcode() == (which_proj?Op_IfTrue:Op_IfFalse), "bad if #2");
      return proj;
    }
  }
  return NULL;
}

//=============================================================================
//------------------------------ProjNode---------------------------------------
uint ProjNode::hash() const {
  // only one input
  return (uintptr_t)in(TypeFunc::Control) + (_con << 1) + (_is_io_use ? 1 : 0);
}
uint ProjNode::cmp( const Node &n ) const { return _con == ((ProjNode&)n)._con && ((ProjNode&)n)._is_io_use == _is_io_use; }
uint ProjNode::size_of() const { return sizeof(ProjNode); }

// Test if we propagate interesting control along this projection
bool ProjNode::is_CFG() const {
  Node *def = in(0);
  return (_con == TypeFunc::Control && def->is_CFG());
}

const Type *ProjNode::bottom_type() const {
  if (in(0) == NULL)  return Type::TOP;
  const Type *tb = in(0)->bottom_type();
  if( tb == Type::TOP ) return Type::TOP;
  if( tb == Type::BOTTOM ) return Type::BOTTOM;
  const TypeTuple *t = tb->is_tuple();
  return t->field_at(_con);
}

const TypePtr *ProjNode::adr_type() const {
  if (bottom_type() == Type::MEMORY) {
    // in(0) might be a narrow MemBar; otherwise we will report TypePtr::BOTTOM
    const TypePtr* adr_type = in(0)->adr_type();
    #ifdef ASSERT
    if (!is_error_reported() && !Node::in_dump())
      assert(adr_type != NULL, "source must have adr_type");
    #endif
    return adr_type;
  }
  assert(bottom_type()->base() != Type::Memory, "no other memories?");
  return NULL;
}

bool ProjNode::pinned() const { return in(0)->pinned(); }
#ifndef PRODUCT
void ProjNode::dump_spec(outputStream *st) const { st->print("#%d",_con); if(_is_io_use) st->print(" (i_o_use)");}
#endif

//----------------------------check_con----------------------------------------
void ProjNode::check_con() const {
  Node* n = in(0);
  if (n == NULL)       return;  // should be assert, but NodeHash makes bogons
  if (n->is_Mach())    return;  // mach. projs. are not type-safe
  if (n->is_Start())   return;  // alas, starts can have mach. projs. also
  if (_con == SCMemProjNode::SCMEMPROJCON ) return;
  const Type* t = n->bottom_type();
  if (t == Type::TOP)  return;  // multi is dead
  assert(_con < t->is_tuple()->cnt(), "ProjNode::_con must be in range");
}

//------------------------------Value------------------------------------------
const Type *ProjNode::Value( PhaseTransform *phase ) const {
  if( !in(0) ) return Type::TOP;
  const Type *t = phase->type(in(0));
  if( t == Type::TOP ) return t;
  if( t == Type::BOTTOM ) return t;
  return t->is_tuple()->field_at(_con);
}

//------------------------------out_RegMask------------------------------------
// Pass the buck uphill
const RegMask &ProjNode::out_RegMask() const {
  return RegMask::Empty;
}

//------------------------------ideal_reg--------------------------------------
uint ProjNode::ideal_reg() const {
  return Matcher::base2reg[bottom_type()->base()];
}