Mercurial > hg > graal-jvmci-8
view src/share/vm/opto/multnode.cpp @ 3249:e1162778c1c8
7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes
author | johnc |
---|---|
date | Thu, 07 Apr 2011 09:53:20 -0700 |
parents | f95d63e2154a |
children | da91efe96a93 |
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/* * Copyright (c) 1997, 2010, 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 "opto/matcher.hpp" #include "opto/multnode.hpp" #include "opto/opcodes.hpp" #include "opto/phaseX.hpp" #include "opto/regmask.hpp" #include "opto/type.hpp" //============================================================================= //------------------------------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()]; }