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comparison src/share/vm/opto/chaitin.cpp @ 729:04fa5affa478

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6709742: find_base_for_derived's use of Ideal NULL is unsafe causing crashes during register allocation Summary: Create a mach node corresponding to ideal node ConP #NULL specifically for derived pointers. Reviewed-by: never
author kvn
date Wed, 22 Apr 2009 17:03:18 -0700
parents fbc12e71c476
children e90521d61f9a
comparison
equal deleted inserted replaced
728:85656c8fa13f 729:04fa5affa478
1421 // See if this happens to be a base. 1421 // See if this happens to be a base.
1422 // NOTE: we use TypePtr instead of TypeOopPtr because we can have 1422 // NOTE: we use TypePtr instead of TypeOopPtr because we can have
1423 // pointers derived from NULL! These are always along paths that 1423 // pointers derived from NULL! These are always along paths that
1424 // can't happen at run-time but the optimizer cannot deduce it so 1424 // can't happen at run-time but the optimizer cannot deduce it so
1425 // we have to handle it gracefully. 1425 // we have to handle it gracefully.
1426 assert(!derived->bottom_type()->isa_narrowoop() ||
1427 derived->bottom_type()->make_ptr()->is_ptr()->_offset == 0, "sanity");
1426 const TypePtr *tj = derived->bottom_type()->isa_ptr(); 1428 const TypePtr *tj = derived->bottom_type()->isa_ptr();
1427 // If its an OOP with a non-zero offset, then it is derived. 1429 // If its an OOP with a non-zero offset, then it is derived.
1428 if( tj->_offset == 0 ) { 1430 if( tj == NULL || tj->_offset == 0 ) {
1429 derived_base_map[derived->_idx] = derived; 1431 derived_base_map[derived->_idx] = derived;
1430 return derived; 1432 return derived;
1431 } 1433 }
1432 // Derived is NULL+offset? Base is NULL! 1434 // Derived is NULL+offset? Base is NULL!
1433 if( derived->is_Con() ) { 1435 if( derived->is_Con() ) {
1434 Node *base = new (C, 1) ConPNode( TypePtr::NULL_PTR ); 1436 Node *base = _matcher.mach_null();
1435 uint no_lidx = 0; // an unmatched constant in debug info has no LRG 1437 assert(base != NULL, "sanity");
1436 _names.extend(base->_idx, no_lidx); 1438 if (base->in(0) == NULL) {
1439 // Initialize it once and make it shared:
1440 // set control to _root and place it into Start block
1441 // (where top() node is placed).
1442 base->init_req(0, _cfg._root);
1443 Block *startb = _cfg._bbs[C->top()->_idx];
1444 startb->_nodes.insert(startb->find_node(C->top()), base );
1445 _cfg._bbs.map( base->_idx, startb );
1446 assert (n2lidx(base) == 0, "should not have LRG yet");
1447 }
1448 if (n2lidx(base) == 0) {
1449 new_lrg(base, maxlrg++);
1450 }
1451 assert(base->in(0) == _cfg._root &&
1452 _cfg._bbs[base->_idx] == _cfg._bbs[C->top()->_idx], "base NULL should be shared");
1437 derived_base_map[derived->_idx] = base; 1453 derived_base_map[derived->_idx] = base;
1438 return base; 1454 return base;
1439 } 1455 }
1440 1456
1441 // Check for AddP-related opcodes 1457 // Check for AddP-related opcodes
1458 derived_base_map[derived->_idx] = base; 1474 derived_base_map[derived->_idx] = base;
1459 return base; 1475 return base;
1460 } 1476 }
1461 1477
1462 // Now we see we need a base-Phi here to merge the bases 1478 // Now we see we need a base-Phi here to merge the bases
1463 base = new (C, derived->req()) PhiNode( derived->in(0), base->bottom_type() ); 1479 const Type *t = base->bottom_type();
1464 for( i = 1; i < derived->req(); i++ ) 1480 base = new (C, derived->req()) PhiNode( derived->in(0), t );
1481 for( i = 1; i < derived->req(); i++ ) {
1465 base->init_req(i, find_base_for_derived(derived_base_map, derived->in(i), maxlrg)); 1482 base->init_req(i, find_base_for_derived(derived_base_map, derived->in(i), maxlrg));
1483 t = t->meet(base->in(i)->bottom_type());
1484 }
1485 base->as_Phi()->set_type(t);
1466 1486
1467 // Search the current block for an existing base-Phi 1487 // Search the current block for an existing base-Phi
1468 Block *b = _cfg._bbs[derived->_idx]; 1488 Block *b = _cfg._bbs[derived->_idx];
1469 for( i = 1; i <= b->end_idx(); i++ ) {// Search for matching Phi 1489 for( i = 1; i <= b->end_idx(); i++ ) {// Search for matching Phi
1470 Node *phi = b->_nodes[i]; 1490 Node *phi = b->_nodes[i];
1558 while ((neighbor = elements.next()) != 0) { 1578 while ((neighbor = elements.next()) != 0) {
1559 // Find reaching DEF for base and derived values 1579 // Find reaching DEF for base and derived values
1560 // This works because we are still in SSA during this call. 1580 // This works because we are still in SSA during this call.
1561 Node *derived = lrgs(neighbor)._def; 1581 Node *derived = lrgs(neighbor)._def;
1562 const TypePtr *tj = derived->bottom_type()->isa_ptr(); 1582 const TypePtr *tj = derived->bottom_type()->isa_ptr();
1583 assert(!derived->bottom_type()->isa_narrowoop() ||
1584 derived->bottom_type()->make_ptr()->is_ptr()->_offset == 0, "sanity");
1563 // If its an OOP with a non-zero offset, then it is derived. 1585 // If its an OOP with a non-zero offset, then it is derived.
1564 if( tj && tj->_offset != 0 && tj->isa_oop_ptr() ) { 1586 if( tj && tj->_offset != 0 && tj->isa_oop_ptr() ) {
1565 Node *base = find_base_for_derived( derived_base_map, derived, maxlrg ); 1587 Node *base = find_base_for_derived( derived_base_map, derived, maxlrg );
1566 assert( base->_idx < _names.Size(), "" ); 1588 assert( base->_idx < _names.Size(), "" );
1567 // Add reaching DEFs of derived pointer and base pointer as a 1589 // Add reaching DEFs of derived pointer and base pointer as a