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duke@435 | 1 | /* |
xdono@631 | 2 | * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | // |
duke@435 | 26 | // Adaptation for C2 of the escape analysis algorithm described in: |
duke@435 | 27 | // |
kvn@500 | 28 | // [Choi99] Jong-Deok Shoi, Manish Gupta, Mauricio Seffano, |
kvn@500 | 29 | // Vugranam C. Sreedhar, Sam Midkiff, |
kvn@500 | 30 | // "Escape Analysis for Java", Procedings of ACM SIGPLAN |
kvn@500 | 31 | // OOPSLA Conference, November 1, 1999 |
duke@435 | 32 | // |
duke@435 | 33 | // The flow-insensitive analysis described in the paper has been implemented. |
duke@435 | 34 | // |
kvn@500 | 35 | // The analysis requires construction of a "connection graph" (CG) for |
kvn@500 | 36 | // the method being analyzed. The nodes of the connection graph are: |
duke@435 | 37 | // |
duke@435 | 38 | // - Java objects (JO) |
duke@435 | 39 | // - Local variables (LV) |
duke@435 | 40 | // - Fields of an object (OF), these also include array elements |
duke@435 | 41 | // |
duke@435 | 42 | // The CG contains 3 types of edges: |
duke@435 | 43 | // |
kvn@500 | 44 | // - PointsTo (-P>) {LV, OF} to JO |
kvn@500 | 45 | // - Deferred (-D>) from {LV, OF} to {LV, OF} |
duke@435 | 46 | // - Field (-F>) from JO to OF |
duke@435 | 47 | // |
duke@435 | 48 | // The following utility functions is used by the algorithm: |
duke@435 | 49 | // |
kvn@500 | 50 | // PointsTo(n) - n is any CG node, it returns the set of JO that n could |
kvn@500 | 51 | // point to. |
duke@435 | 52 | // |
kvn@500 | 53 | // The algorithm describes how to construct the connection graph |
kvn@500 | 54 | // in the following 4 cases: |
duke@435 | 55 | // |
duke@435 | 56 | // Case Edges Created |
duke@435 | 57 | // |
kvn@500 | 58 | // (1) p = new T() LV -P> JO |
kvn@500 | 59 | // (2) p = q LV -D> LV |
kvn@500 | 60 | // (3) p.f = q JO -F> OF, OF -D> LV |
kvn@500 | 61 | // (4) p = q.f JO -F> OF, LV -D> OF |
duke@435 | 62 | // |
kvn@500 | 63 | // In all these cases, p and q are local variables. For static field |
kvn@500 | 64 | // references, we can construct a local variable containing a reference |
kvn@500 | 65 | // to the static memory. |
duke@435 | 66 | // |
duke@435 | 67 | // C2 does not have local variables. However for the purposes of constructing |
duke@435 | 68 | // the connection graph, the following IR nodes are treated as local variables: |
duke@435 | 69 | // Phi (pointer values) |
duke@435 | 70 | // LoadP |
kvn@500 | 71 | // Proj#5 (value returned from callnodes including allocations) |
kvn@500 | 72 | // CheckCastPP, CastPP |
duke@435 | 73 | // |
kvn@500 | 74 | // The LoadP, Proj and CheckCastPP behave like variables assigned to only once. |
kvn@500 | 75 | // Only a Phi can have multiple assignments. Each input to a Phi is treated |
duke@435 | 76 | // as an assignment to it. |
duke@435 | 77 | // |
kvn@500 | 78 | // The following node types are JavaObject: |
duke@435 | 79 | // |
duke@435 | 80 | // top() |
duke@435 | 81 | // Allocate |
duke@435 | 82 | // AllocateArray |
duke@435 | 83 | // Parm (for incoming arguments) |
kvn@500 | 84 | // CastX2P ("unsafe" operations) |
duke@435 | 85 | // CreateEx |
duke@435 | 86 | // ConP |
duke@435 | 87 | // LoadKlass |
kvn@500 | 88 | // ThreadLocal |
duke@435 | 89 | // |
duke@435 | 90 | // AddP nodes are fields. |
duke@435 | 91 | // |
duke@435 | 92 | // After building the graph, a pass is made over the nodes, deleting deferred |
duke@435 | 93 | // nodes and copying the edges from the target of the deferred edge to the |
duke@435 | 94 | // source. This results in a graph with no deferred edges, only: |
duke@435 | 95 | // |
duke@435 | 96 | // LV -P> JO |
kvn@500 | 97 | // OF -P> JO (the object whose oop is stored in the field) |
duke@435 | 98 | // JO -F> OF |
duke@435 | 99 | // |
duke@435 | 100 | // Then, for each node which is GlobalEscape, anything it could point to |
duke@435 | 101 | // is marked GlobalEscape. Finally, for any node marked ArgEscape, anything |
duke@435 | 102 | // it could point to is marked ArgEscape. |
duke@435 | 103 | // |
duke@435 | 104 | |
duke@435 | 105 | class Compile; |
duke@435 | 106 | class Node; |
duke@435 | 107 | class CallNode; |
duke@435 | 108 | class PhiNode; |
duke@435 | 109 | class PhaseTransform; |
duke@435 | 110 | class Type; |
duke@435 | 111 | class TypePtr; |
duke@435 | 112 | class VectorSet; |
duke@435 | 113 | |
duke@435 | 114 | class PointsToNode { |
duke@435 | 115 | friend class ConnectionGraph; |
duke@435 | 116 | public: |
duke@435 | 117 | typedef enum { |
kvn@500 | 118 | UnknownType = 0, |
kvn@500 | 119 | JavaObject = 1, |
kvn@500 | 120 | LocalVar = 2, |
kvn@500 | 121 | Field = 3 |
duke@435 | 122 | } NodeType; |
duke@435 | 123 | |
duke@435 | 124 | typedef enum { |
duke@435 | 125 | UnknownEscape = 0, |
kvn@500 | 126 | NoEscape = 1, // A scalar replaceable object with unique type. |
kvn@500 | 127 | ArgEscape = 2, // An object passed as argument or referenced by |
kvn@500 | 128 | // argument (and not globally escape during call). |
kvn@500 | 129 | GlobalEscape = 3 // An object escapes the method and thread. |
duke@435 | 130 | } EscapeState; |
duke@435 | 131 | |
duke@435 | 132 | typedef enum { |
duke@435 | 133 | UnknownEdge = 0, |
duke@435 | 134 | PointsToEdge = 1, |
duke@435 | 135 | DeferredEdge = 2, |
duke@435 | 136 | FieldEdge = 3 |
duke@435 | 137 | } EdgeType; |
duke@435 | 138 | |
duke@435 | 139 | private: |
duke@435 | 140 | enum { |
duke@435 | 141 | EdgeMask = 3, |
duke@435 | 142 | EdgeShift = 2, |
duke@435 | 143 | |
duke@435 | 144 | INITIAL_EDGE_COUNT = 4 |
duke@435 | 145 | }; |
duke@435 | 146 | |
duke@435 | 147 | NodeType _type; |
duke@435 | 148 | EscapeState _escape; |
kvn@500 | 149 | GrowableArray<uint>* _edges; // outgoing edges |
duke@435 | 150 | |
duke@435 | 151 | public: |
kvn@500 | 152 | Node* _node; // Ideal node corresponding to this PointsTo node. |
kvn@500 | 153 | int _offset; // Object fields offsets. |
kvn@500 | 154 | bool _scalar_replaceable;// Not escaped object could be replaced with scalar |
kvn@500 | 155 | bool _hidden_alias; // This node is an argument to a function. |
kvn@500 | 156 | // which may return it creating a hidden alias. |
duke@435 | 157 | |
kvn@500 | 158 | PointsToNode(): |
kvn@500 | 159 | _type(UnknownType), |
kvn@500 | 160 | _escape(UnknownEscape), |
kvn@500 | 161 | _edges(NULL), |
kvn@500 | 162 | _node(NULL), |
kvn@500 | 163 | _offset(-1), |
kvn@500 | 164 | _scalar_replaceable(true), |
kvn@500 | 165 | _hidden_alias(false) {} |
duke@435 | 166 | |
duke@435 | 167 | |
duke@435 | 168 | EscapeState escape_state() const { return _escape; } |
duke@435 | 169 | NodeType node_type() const { return _type;} |
duke@435 | 170 | int offset() { return _offset;} |
duke@435 | 171 | |
duke@435 | 172 | void set_offset(int offs) { _offset = offs;} |
duke@435 | 173 | void set_escape_state(EscapeState state) { _escape = state; } |
duke@435 | 174 | void set_node_type(NodeType ntype) { |
duke@435 | 175 | assert(_type == UnknownType || _type == ntype, "Can't change node type"); |
duke@435 | 176 | _type = ntype; |
duke@435 | 177 | } |
duke@435 | 178 | |
duke@435 | 179 | // count of outgoing edges |
duke@435 | 180 | uint edge_count() const { return (_edges == NULL) ? 0 : _edges->length(); } |
kvn@679 | 181 | |
duke@435 | 182 | // node index of target of outgoing edge "e" |
kvn@679 | 183 | uint edge_target(uint e) const { |
kvn@679 | 184 | assert(_edges != NULL, "valid edge index"); |
kvn@679 | 185 | return (_edges->at(e) >> EdgeShift); |
kvn@679 | 186 | } |
duke@435 | 187 | // type of outgoing edge "e" |
kvn@679 | 188 | EdgeType edge_type(uint e) const { |
kvn@679 | 189 | assert(_edges != NULL, "valid edge index"); |
kvn@679 | 190 | return (EdgeType) (_edges->at(e) & EdgeMask); |
kvn@679 | 191 | } |
kvn@679 | 192 | |
duke@435 | 193 | // add a edge of the specified type pointing to the specified target |
duke@435 | 194 | void add_edge(uint targIdx, EdgeType et); |
kvn@679 | 195 | |
duke@435 | 196 | // remove an edge of the specified type pointing to the specified target |
duke@435 | 197 | void remove_edge(uint targIdx, EdgeType et); |
kvn@679 | 198 | |
duke@435 | 199 | #ifndef PRODUCT |
kvn@688 | 200 | void dump(bool print_state=true) const; |
duke@435 | 201 | #endif |
duke@435 | 202 | |
duke@435 | 203 | }; |
duke@435 | 204 | |
duke@435 | 205 | class ConnectionGraph: public ResourceObj { |
duke@435 | 206 | private: |
kvn@679 | 207 | GrowableArray<PointsToNode> _nodes; // Connection graph nodes indexed |
kvn@500 | 208 | // by ideal node index. |
duke@435 | 209 | |
kvn@500 | 210 | Unique_Node_List _delayed_worklist; // Nodes to be processed before |
kvn@500 | 211 | // the call build_connection_graph(). |
duke@435 | 212 | |
kvn@1535 | 213 | GrowableArray<MergeMemNode *> _mergemem_worklist; // List of all MergeMem nodes |
kvn@1535 | 214 | |
kvn@500 | 215 | VectorSet _processed; // Records which nodes have been |
kvn@500 | 216 | // processed. |
kvn@500 | 217 | |
kvn@500 | 218 | bool _collecting; // Indicates whether escape information |
kvn@500 | 219 | // is still being collected. If false, |
kvn@500 | 220 | // no new nodes will be processed. |
kvn@500 | 221 | |
kvn@500 | 222 | uint _phantom_object; // Index of globally escaping object |
kvn@500 | 223 | // that pointer values loaded from |
kvn@500 | 224 | // a field which has not been set |
kvn@500 | 225 | // are assumed to point to. |
kvn@688 | 226 | uint _oop_null; // ConP(#NULL) |
kvn@688 | 227 | uint _noop_null; // ConN(#NULL) |
kvn@500 | 228 | |
kvn@500 | 229 | Compile * _compile; // Compile object for current compilation |
duke@435 | 230 | |
kvn@679 | 231 | // Address of an element in _nodes. Used when the element is to be modified |
kvn@679 | 232 | PointsToNode *ptnode_adr(uint idx) const { |
kvn@679 | 233 | // There should be no new ideal nodes during ConnectionGraph build, |
kvn@679 | 234 | // growableArray::adr_at() will throw assert otherwise. |
kvn@679 | 235 | return _nodes.adr_at(idx); |
duke@435 | 236 | } |
kvn@679 | 237 | uint nodes_size() const { return _nodes.length(); } |
duke@435 | 238 | |
kvn@500 | 239 | // Add node to ConnectionGraph. |
kvn@500 | 240 | void add_node(Node *n, PointsToNode::NodeType nt, PointsToNode::EscapeState es, bool done); |
kvn@500 | 241 | |
duke@435 | 242 | // offset of a field reference |
kvn@500 | 243 | int address_offset(Node* adr, PhaseTransform *phase); |
duke@435 | 244 | |
duke@435 | 245 | // compute the escape state for arguments to a call |
duke@435 | 246 | void process_call_arguments(CallNode *call, PhaseTransform *phase); |
duke@435 | 247 | |
duke@435 | 248 | // compute the escape state for the return value of a call |
duke@435 | 249 | void process_call_result(ProjNode *resproj, PhaseTransform *phase); |
duke@435 | 250 | |
kvn@500 | 251 | // Populate Connection Graph with Ideal nodes. |
kvn@500 | 252 | void record_for_escape_analysis(Node *n, PhaseTransform *phase); |
duke@435 | 253 | |
kvn@500 | 254 | // Build Connection Graph and set nodes escape state. |
kvn@500 | 255 | void build_connection_graph(Node *n, PhaseTransform *phase); |
duke@435 | 256 | |
duke@435 | 257 | // walk the connection graph starting at the node corresponding to "n" and |
duke@435 | 258 | // add the index of everything it could point to, to "ptset". This may cause |
duke@435 | 259 | // Phi's encountered to get (re)processed (which requires "phase".) |
duke@435 | 260 | void PointsTo(VectorSet &ptset, Node * n, PhaseTransform *phase); |
duke@435 | 261 | |
duke@435 | 262 | // Edge manipulation. The "from_i" and "to_i" arguments are the |
duke@435 | 263 | // node indices of the source and destination of the edge |
duke@435 | 264 | void add_pointsto_edge(uint from_i, uint to_i); |
duke@435 | 265 | void add_deferred_edge(uint from_i, uint to_i); |
duke@435 | 266 | void add_field_edge(uint from_i, uint to_i, int offs); |
duke@435 | 267 | |
duke@435 | 268 | |
duke@435 | 269 | // Add an edge to node given by "to_i" from any field of adr_i whose offset |
duke@435 | 270 | // matches "offset" A deferred edge is added if to_i is a LocalVar, and |
duke@435 | 271 | // a pointsto edge is added if it is a JavaObject |
duke@435 | 272 | void add_edge_from_fields(uint adr, uint to_i, int offs); |
duke@435 | 273 | |
kvn@500 | 274 | // Add a deferred edge from node given by "from_i" to any field |
kvn@500 | 275 | // of adr_i whose offset matches "offset" |
duke@435 | 276 | void add_deferred_edge_to_fields(uint from_i, uint adr, int offs); |
duke@435 | 277 | |
duke@435 | 278 | |
duke@435 | 279 | // Remove outgoing deferred edges from the node referenced by "ni". |
duke@435 | 280 | // Any outgoing edges from the target of the deferred edge are copied |
duke@435 | 281 | // to "ni". |
kvn@536 | 282 | void remove_deferred(uint ni, GrowableArray<uint>* deferred_edges, VectorSet* visited); |
duke@435 | 283 | |
duke@435 | 284 | Node_Array _node_map; // used for bookeeping during type splitting |
duke@435 | 285 | // Used for the following purposes: |
duke@435 | 286 | // Memory Phi - most recent unique Phi split out |
duke@435 | 287 | // from this Phi |
duke@435 | 288 | // MemNode - new memory input for this node |
duke@435 | 289 | // ChecCastPP - allocation that this is a cast of |
duke@435 | 290 | // allocation - CheckCastPP of the allocation |
kvn@728 | 291 | bool split_AddP(Node *addp, Node *base, PhaseGVN *igvn); |
duke@435 | 292 | PhiNode *create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, PhaseGVN *igvn, bool &new_created); |
duke@435 | 293 | PhiNode *split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, PhaseGVN *igvn); |
kvn@1536 | 294 | void move_inst_mem(Node* n, GrowableArray<PhiNode *> &orig_phis, PhaseGVN *igvn); |
kvn@500 | 295 | Node *find_inst_mem(Node *mem, int alias_idx,GrowableArray<PhiNode *> &orig_phi_worklist, PhaseGVN *igvn); |
kvn@500 | 296 | |
duke@435 | 297 | // Propagate unique types created for unescaped allocated objects |
duke@435 | 298 | // through the graph |
duke@435 | 299 | void split_unique_types(GrowableArray<Node *> &alloc_worklist); |
duke@435 | 300 | |
duke@435 | 301 | // manage entries in _node_map |
duke@435 | 302 | void set_map(int idx, Node *n) { _node_map.map(idx, n); } |
duke@435 | 303 | Node *get_map(int idx) { return _node_map[idx]; } |
duke@435 | 304 | PhiNode *get_map_phi(int idx) { |
duke@435 | 305 | Node *phi = _node_map[idx]; |
duke@435 | 306 | return (phi == NULL) ? NULL : phi->as_Phi(); |
duke@435 | 307 | } |
duke@435 | 308 | |
duke@435 | 309 | // Notify optimizer that a node has been modified |
duke@435 | 310 | // Node: This assumes that escape analysis is run before |
duke@435 | 311 | // PhaseIterGVN creation |
duke@435 | 312 | void record_for_optimizer(Node *n) { |
duke@435 | 313 | _compile->record_for_igvn(n); |
duke@435 | 314 | } |
duke@435 | 315 | |
duke@435 | 316 | // Set the escape state of a node |
duke@435 | 317 | void set_escape_state(uint ni, PointsToNode::EscapeState es); |
duke@435 | 318 | |
kvn@1535 | 319 | // Search for objects which are not scalar replaceable. |
kvn@1535 | 320 | void verify_escape_state(int nidx, VectorSet& ptset, PhaseTransform* phase); |
kvn@1535 | 321 | |
duke@435 | 322 | public: |
duke@435 | 323 | ConnectionGraph(Compile *C); |
duke@435 | 324 | |
kvn@679 | 325 | // Check for non-escaping candidates |
kvn@679 | 326 | static bool has_candidates(Compile *C); |
kvn@679 | 327 | |
kvn@500 | 328 | // Compute the escape information |
kvn@679 | 329 | bool compute_escape(); |
duke@435 | 330 | |
duke@435 | 331 | // escape state of a node |
duke@435 | 332 | PointsToNode::EscapeState escape_state(Node *n, PhaseTransform *phase); |
kvn@500 | 333 | // other information we have collected |
kvn@500 | 334 | bool is_scalar_replaceable(Node *n) { |
kvn@679 | 335 | if (_collecting || (n->_idx >= nodes_size())) |
kvn@500 | 336 | return false; |
kvn@679 | 337 | PointsToNode* ptn = ptnode_adr(n->_idx); |
kvn@679 | 338 | return ptn->escape_state() == PointsToNode::NoEscape && ptn->_scalar_replaceable; |
kvn@500 | 339 | } |
duke@435 | 340 | |
duke@435 | 341 | bool hidden_alias(Node *n) { |
kvn@679 | 342 | if (_collecting || (n->_idx >= nodes_size())) |
duke@435 | 343 | return true; |
kvn@679 | 344 | PointsToNode* ptn = ptnode_adr(n->_idx); |
kvn@679 | 345 | return (ptn->escape_state() != PointsToNode::NoEscape) || ptn->_hidden_alias; |
duke@435 | 346 | } |
duke@435 | 347 | |
duke@435 | 348 | #ifndef PRODUCT |
duke@435 | 349 | void dump(); |
duke@435 | 350 | #endif |
duke@435 | 351 | }; |