src/share/vm/opto/node.cpp

rev 9822 : 8146612: C2: Precedence edges specification violated
Reviewed-by: kvn

*** 1,7 ****
  /*
!  * Copyright (c) 1997, 2015, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 1997, 2016, 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.
*** 795,805 ****
            "remove node from hash table before modifying it");
    // First remove corresponding def-use edge
    Node *n = in(idx);
    if (n != NULL) n->del_out((Node *)this);
    _in[idx] = in(--_cnt);  // Compact the array
!   _in[_cnt] = NULL;       // NULL out emptied slot
    Compile::current()->record_modified_node(this);
  }
  
  //------------------------------del_req_ordered--------------------------------
  // Delete the required edge and compact the edge array with preserved order
--- 795,806 ----
            "remove node from hash table before modifying it");
    // First remove corresponding def-use edge
    Node *n = in(idx);
    if (n != NULL) n->del_out((Node *)this);
    _in[idx] = in(--_cnt); // Compact the array
!   // Avoid spec violation: Gap in prec edges.
!   close_prec_gap_at(_cnt);
    Compile::current()->record_modified_node(this);
  }
  
  //------------------------------del_req_ordered--------------------------------
  // Delete the required edge and compact the edge array with preserved order
*** 808,821 ****
    assert( !VerifyHashTableKeys || _hash_lock == 0,
            "remove node from hash table before modifying it");
    // First remove corresponding def-use edge
    Node *n = in(idx);
    if (n != NULL) n->del_out((Node *)this);
!   if (idx < _cnt - 1) { // Not last edge ?
!     Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx-1)*sizeof(Node*)));
    }
!   _in[--_cnt] = NULL;   // NULL out emptied slot
    Compile::current()->record_modified_node(this);
  }
  
  //------------------------------ins_req----------------------------------------
  // Insert a new required input at the end
--- 809,823 ----
    assert( !VerifyHashTableKeys || _hash_lock == 0,
            "remove node from hash table before modifying it");
    // First remove corresponding def-use edge
    Node *n = in(idx);
    if (n != NULL) n->del_out((Node *)this);
!   if (idx < --_cnt) {    // Not last edge ?
!     Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx)*sizeof(Node*)));
    }
!   // Avoid spec violation: Gap in prec edges.
!   close_prec_gap_at(_cnt);
    Compile::current()->record_modified_node(this);
  }
  
  //------------------------------ins_req----------------------------------------
  // Insert a new required input at the end
*** 843,856 ****
  int Node::replace_edge(Node* old, Node* neww) {
    if (old == neww)  return 0;  // nothing to do
    uint nrep = 0;
    for (uint i = 0; i < len(); i++) {
      if (in(i) == old) {
!       if (i < req())
          set_req(i, neww);
!       else
          set_prec(i, neww);
        nrep++;
      }
    }
    return nrep;
  }
--- 845,860 ----
  int Node::replace_edge(Node* old, Node* neww) {
    if (old == neww)  return 0;  // nothing to do
    uint nrep = 0;
    for (uint i = 0; i < len(); i++) {
      if (in(i) == old) {
!       if (i < req()) {
          set_req(i, neww);
!       } else {
!         assert(find_prec_edge(neww) == -1, "spec violation: duplicated prec edge (node %d -> %d)", _idx, neww->_idx);
          set_prec(i, neww);
+       }
        nrep++;
      }
    }
    return nrep;
  }
*** 980,1007 ****
    if( _cnt >= _max || in(_max-1) )
      grow( _max+1 );
  
    // Find a precedence edge to move
    uint i = _cnt;
!   while( in(i) != NULL ) i++;
    _in[i] = n;                                // Stuff prec edge over NULL
    if ( n != NULL) n->add_out((Node *)this);  // Add mirror edge
  }
  
  //------------------------------rm_prec----------------------------------------
  // Remove a precedence input.  Precedence inputs are unordered, with
  // duplicates removed and NULLs packed down at the end.
  void Node::rm_prec( uint j ) {
! 
!   // Find end of precedence list to pack NULLs
!   uint i;
!   for( i=j; i<_max; i++ )
!     if( !_in[i] )               // Find the NULL at end of prec edge list
!       break;
!   if (_in[j] != NULL) _in[j]->del_out((Node *)this);
!   _in[j] = _in[--i];            // Move last element over removed guy
!   _in[i] = NULL;                // NULL out last element
  }
  
  //------------------------------size_of----------------------------------------
  uint Node::size_of() const { return sizeof(*this); }
  
--- 984,1014 ----
    if( _cnt >= _max || in(_max-1) )
      grow( _max+1 );
  
    // Find a precedence edge to move
    uint i = _cnt;
!   while( in(i) != NULL ) {
!     if (in(i) == n) return; // Avoid spec violation: duplicated prec edge.
!     i++;
!   }
    _in[i] = n;                                // Stuff prec edge over NULL
    if ( n != NULL) n->add_out((Node *)this);  // Add mirror edge
+ 
+ #ifdef ASSERT
+   while ((++i)<_max) { assert(_in[i] == NULL, "spec violation: Gap in prec edges (node %d)", _idx); }
+ #endif
  }
  
  //------------------------------rm_prec----------------------------------------
  // Remove a precedence input.  Precedence inputs are unordered, with
  // duplicates removed and NULLs packed down at the end.
  void Node::rm_prec( uint j ) {
!   assert(j < _max, "oob: i=%d, _max=%d", j, _max);
!   assert(j >= _cnt, "not a precedence edge");
!   if (_in[j] == NULL) return;   // Avoid spec violation: Gap in prec edges.
!   _in[j]->del_out((Node *)this);
!   close_prec_gap_at(j);
  }
  
  //------------------------------size_of----------------------------------------
  uint Node::size_of() const { return sizeof(*this); }