jdk8-mips64-public/hotspot: src/share/vm/opto/escape.hpp@82a980778b92 (annotated)

src/share/vm/opto/escape.hpp@82a980778b92 (annotated)

src/share/vm/opto/escape.hpp

Thu, 05 Feb 2009 11:42:10 -0800

author: never
date: Thu, 05 Feb 2009 11:42:10 -0800
changeset 979: 82a980778b92
parent 728: c3e045194476
child 1535: f96a1a986f7b
permissions: -rw-r--r--

6793828: G1: invariant: queues are empty when activated
Reviewed-by: jrose, kvn

 /*
  * Copyright 2005-2008 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.
  *
  */
 //
 // Adaptation for C2 of the escape analysis algorithm described in:
 //
 // [Choi99] Jong-Deok Shoi, Manish Gupta, Mauricio Seffano,
 //          Vugranam C. Sreedhar, Sam Midkiff,
 //          "Escape Analysis for Java", Procedings of ACM SIGPLAN
 //          OOPSLA  Conference, November 1, 1999
 //
 // The flow-insensitive analysis described in the paper has been implemented.
 //
 // The analysis requires construction of a "connection graph" (CG) for
 // the method being analyzed.  The nodes of the connection graph are:
 //
 //     -  Java objects (JO)
 //     -  Local variables (LV)
 //     -  Fields of an object (OF),  these also include array elements
 //
 // The CG contains 3 types of edges:
 //
 //   -  PointsTo  (-P>)    {LV, OF} to JO
 //   -  Deferred  (-D>)    from {LV, OF} to {LV, OF}
 //   -  Field     (-F>)    from JO to OF
 //
 // The following  utility functions is used by the algorithm:
 //
 //   PointsTo(n) - n is any CG node, it returns the set of JO that n could
 //                 point to.
 //
 // The algorithm describes how to construct the connection graph
 // in the following 4 cases:
 //
 //          Case                  Edges Created
 //
 // (1)   p   = new T()              LV -P> JO
 // (2)   p   = q                    LV -D> LV
 // (3)   p.f = q                    JO -F> OF,  OF -D> LV
 // (4)   p   = q.f                  JO -F> OF,  LV -D> OF
 //
 // In all these cases, p and q are local variables.  For static field
 // references, we can construct a local variable containing a reference
 // to the static memory.
 //
 // C2 does not have local variables.  However for the purposes of constructing
 // the connection graph, the following IR nodes are treated as local variables:
 //     Phi    (pointer values)
 //     LoadP
 //     Proj#5 (value returned from callnodes including allocations)
 //     CheckCastPP, CastPP
 //
 // The LoadP, Proj and CheckCastPP behave like variables assigned to only once.
 // Only a Phi can have multiple assignments.  Each input to a Phi is treated
 // as an assignment to it.
 //
 // The following node types are JavaObject:
 //
 //     top()
 //     Allocate
 //     AllocateArray
 //     Parm  (for incoming arguments)
 //     CastX2P ("unsafe" operations)
 //     CreateEx
 //     ConP
 //     LoadKlass
 //     ThreadLocal
 //
 // AddP nodes are fields.
 //
 // After building the graph, a pass is made over the nodes, deleting deferred
 // nodes and copying the edges from the target of the deferred edge to the
 // source.  This results in a graph with no deferred edges, only:
 //
 //    LV -P> JO
 //    OF -P> JO (the object whose oop is stored in the field)
 //    JO -F> OF
 //
 // Then, for each node which is GlobalEscape, anything it could point to
 // is marked GlobalEscape.  Finally, for any node marked ArgEscape, anything
 // it could point to is marked ArgEscape.
 //
 class  Compile;
 class  Node;
 class  CallNode;
 class  PhiNode;
 class  PhaseTransform;
 class  Type;
 class  TypePtr;
 class  VectorSet;
 class PointsToNode {
 friend class ConnectionGraph;
 public:
   typedef enum {
     UnknownType = 0,
     JavaObject  = 1,
     LocalVar    = 2,
     Field       = 3
   } NodeType;
   typedef enum {
     UnknownEscape = 0,
     NoEscape      = 1, // A scalar replaceable object with unique type.
     ArgEscape     = 2, // An object passed as argument or referenced by
                        // argument (and not globally escape during call).
     GlobalEscape  = 3  // An object escapes the method and thread.
   } EscapeState;
   typedef enum {
     UnknownEdge   = 0,
     PointsToEdge  = 1,
     DeferredEdge  = 2,
     FieldEdge     = 3
   } EdgeType;
 private:
   enum {
     EdgeMask = 3,
     EdgeShift = 2,
     INITIAL_EDGE_COUNT = 4
   };
   NodeType             _type;
   EscapeState          _escape;
   GrowableArray<uint>* _edges;   // outgoing edges
 public:
   Node* _node;              // Ideal node corresponding to this PointsTo node.
   int   _offset;            // Object fields offsets.
   bool  _scalar_replaceable;// Not escaped object could be replaced with scalar
   bool  _hidden_alias;      // This node is an argument to a function.
                             // which may return it creating a hidden alias.
   PointsToNode():
     _type(UnknownType),
     _escape(UnknownEscape),
     _edges(NULL),
     _node(NULL),
     _offset(-1),
     _scalar_replaceable(true),
     _hidden_alias(false) {}
   EscapeState escape_state() const { return _escape; }
   NodeType node_type() const { return _type;}
   int offset() { return _offset;}
   void set_offset(int offs) { _offset = offs;}
   void set_escape_state(EscapeState state) { _escape = state; }
   void set_node_type(NodeType ntype) {
     assert(_type == UnknownType || _type == ntype, "Can't change node type");
     _type = ntype;
   }
   // count of outgoing edges
   uint edge_count() const { return (_edges == NULL) ? 0 : _edges->length(); }
   // node index of target of outgoing edge "e"
   uint edge_target(uint e) const {
     assert(_edges != NULL, "valid edge index");
     return (_edges->at(e) >> EdgeShift);
   }
   // type of outgoing edge "e"
   EdgeType edge_type(uint e) const {
     assert(_edges != NULL, "valid edge index");
     return (EdgeType) (_edges->at(e) & EdgeMask);
   }
   // add a edge of the specified type pointing to the specified target
   void add_edge(uint targIdx, EdgeType et);
   // remove an edge of the specified type pointing to the specified target
   void remove_edge(uint targIdx, EdgeType et);
 #ifndef PRODUCT
   void dump(bool print_state=true) const;
 #endif
 };
 class ConnectionGraph: public ResourceObj {
 private:
   GrowableArray<PointsToNode>  _nodes; // Connection graph nodes indexed
                                        // by ideal node index.
   Unique_Node_List  _delayed_worklist; // Nodes to be processed before
                                        // the call build_connection_graph().
   VectorSet                _processed; // Records which nodes have been
                                        // processed.
   bool                    _collecting; // Indicates whether escape information
                                        // is still being collected. If false,
                                        // no new nodes will be processed.
   uint                _phantom_object; // Index of globally escaping object
                                        // that pointer values loaded from
                                        // a field which has not been set
                                        // are assumed to point to.
   uint                      _oop_null; // ConP(#NULL)
   uint                     _noop_null; // ConN(#NULL)
   Compile *                  _compile; // Compile object for current compilation
   // Address of an element in _nodes.  Used when the element is to be modified
   PointsToNode *ptnode_adr(uint idx) const {
     // There should be no new ideal nodes during ConnectionGraph build,
     // growableArray::adr_at() will throw assert otherwise.
     return _nodes.adr_at(idx);
   }
   uint nodes_size() const { return _nodes.length(); }
   // Add node to ConnectionGraph.
   void add_node(Node *n, PointsToNode::NodeType nt, PointsToNode::EscapeState es, bool done);
   // offset of a field reference
   int address_offset(Node* adr, PhaseTransform *phase);
   // compute the escape state for arguments to a call
   void process_call_arguments(CallNode *call, PhaseTransform *phase);
   // compute the escape state for the return value of a call
   void process_call_result(ProjNode *resproj, PhaseTransform *phase);
   // Populate Connection Graph with Ideal nodes.
   void record_for_escape_analysis(Node *n, PhaseTransform *phase);
   // Build Connection Graph and set nodes escape state.
   void build_connection_graph(Node *n, PhaseTransform *phase);
   // walk the connection graph starting at the node corresponding to "n" and
   // add the index of everything it could point to, to "ptset".  This may cause
   // Phi's encountered to get (re)processed  (which requires "phase".)
   void PointsTo(VectorSet &ptset, Node * n, PhaseTransform *phase);
   //  Edge manipulation.  The "from_i" and "to_i" arguments are the
   //  node indices of the source and destination of the edge
   void add_pointsto_edge(uint from_i, uint to_i);
   void add_deferred_edge(uint from_i, uint to_i);
   void add_field_edge(uint from_i, uint to_i, int offs);
   // Add an edge to node given by "to_i" from any field of adr_i whose offset
   // matches "offset"  A deferred edge is added if to_i is a LocalVar, and
   // a pointsto edge is added if it is a JavaObject
   void add_edge_from_fields(uint adr, uint to_i, int offs);
   // Add a deferred  edge from node given by "from_i" to any field
   // of adr_i whose offset matches "offset"
   void add_deferred_edge_to_fields(uint from_i, uint adr, int offs);
   // Remove outgoing deferred edges from the node referenced by "ni".
   // Any outgoing edges from the target of the deferred edge are copied
   // to "ni".
   void remove_deferred(uint ni, GrowableArray<uint>* deferred_edges, VectorSet* visited);
   Node_Array _node_map; // used for bookeeping during type splitting
                         // Used for the following purposes:
                         // Memory Phi    - most recent unique Phi split out
                         //                 from this Phi
                         // MemNode       - new memory input for this node
                         // ChecCastPP    - allocation that this is a cast of
                         // allocation    - CheckCastPP of the allocation
   bool split_AddP(Node *addp, Node *base,  PhaseGVN  *igvn);
   PhiNode *create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn, bool &new_created);
   PhiNode *split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn);
   Node *find_mem(Node *mem, int alias_idx, PhaseGVN  *igvn);
   Node *find_inst_mem(Node *mem, int alias_idx,GrowableArray<PhiNode *>  &orig_phi_worklist,  PhaseGVN  *igvn);
   // Propagate unique types created for unescaped allocated objects
   // through the graph
   void split_unique_types(GrowableArray<Node *>  &alloc_worklist);
   // manage entries in _node_map
   void  set_map(int idx, Node *n)        { _node_map.map(idx, n); }
   void  set_map_phi(int idx, PhiNode *p) { _node_map.map(idx, (Node *) p); }
   Node *get_map(int idx)                 { return _node_map[idx]; }
   PhiNode *get_map_phi(int idx) {
     Node *phi = _node_map[idx];
     return (phi == NULL) ? NULL : phi->as_Phi();
   }
   // Notify optimizer that a node has been modified
   // Node:  This assumes that escape analysis is run before
   //        PhaseIterGVN creation
   void record_for_optimizer(Node *n) {
     _compile->record_for_igvn(n);
   }
   // Set the escape state of a node
   void set_escape_state(uint ni, PointsToNode::EscapeState es);
 public:
   ConnectionGraph(Compile *C);
   // Check for non-escaping candidates
   static bool has_candidates(Compile *C);
   // Compute the escape information
   bool compute_escape();
   // escape state of a node
   PointsToNode::EscapeState escape_state(Node *n, PhaseTransform *phase);
   // other information we have collected
   bool is_scalar_replaceable(Node *n) {
     if (_collecting || (n->_idx >= nodes_size()))
       return false;
     PointsToNode* ptn = ptnode_adr(n->_idx);
     return ptn->escape_state() == PointsToNode::NoEscape && ptn->_scalar_replaceable;
   }
   bool hidden_alias(Node *n) {
     if (_collecting || (n->_idx >= nodes_size()))
       return true;
     PointsToNode* ptn = ptnode_adr(n->_idx);
     return (ptn->escape_state() != PointsToNode::NoEscape) || ptn->_hidden_alias;
   }
 #ifndef PRODUCT
   void dump();
 #endif
 };

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src/share/vm/opto/escape.hpp@82a980778b92 (annotated)

src/share/vm/opto/escape.hpp