Mon, 24 Nov 2014 07:29:03 -0800
8058148: MaxNodeLimit and LiveNodeCountInliningCutoff
Reviewed-by: kvn, roland
1 /*
2 * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #ifndef SHARE_VM_OPTO_ESCAPE_HPP
26 #define SHARE_VM_OPTO_ESCAPE_HPP
28 #include "opto/addnode.hpp"
29 #include "opto/node.hpp"
30 #include "utilities/growableArray.hpp"
32 //
33 // Adaptation for C2 of the escape analysis algorithm described in:
34 //
35 // [Choi99] Jong-Deok Shoi, Manish Gupta, Mauricio Seffano,
36 // Vugranam C. Sreedhar, Sam Midkiff,
37 // "Escape Analysis for Java", Procedings of ACM SIGPLAN
38 // OOPSLA Conference, November 1, 1999
39 //
40 // The flow-insensitive analysis described in the paper has been implemented.
41 //
42 // The analysis requires construction of a "connection graph" (CG) for
43 // the method being analyzed. The nodes of the connection graph are:
44 //
45 // - Java objects (JO)
46 // - Local variables (LV)
47 // - Fields of an object (OF), these also include array elements
48 //
49 // The CG contains 3 types of edges:
50 //
51 // - PointsTo (-P>) {LV, OF} to JO
52 // - Deferred (-D>) from {LV, OF} to {LV, OF}
53 // - Field (-F>) from JO to OF
54 //
55 // The following utility functions is used by the algorithm:
56 //
57 // PointsTo(n) - n is any CG node, it returns the set of JO that n could
58 // point to.
59 //
60 // The algorithm describes how to construct the connection graph
61 // in the following 4 cases:
62 //
63 // Case Edges Created
64 //
65 // (1) p = new T() LV -P> JO
66 // (2) p = q LV -D> LV
67 // (3) p.f = q JO -F> OF, OF -D> LV
68 // (4) p = q.f JO -F> OF, LV -D> OF
69 //
70 // In all these cases, p and q are local variables. For static field
71 // references, we can construct a local variable containing a reference
72 // to the static memory.
73 //
74 // C2 does not have local variables. However for the purposes of constructing
75 // the connection graph, the following IR nodes are treated as local variables:
76 // Phi (pointer values)
77 // LoadP, LoadN
78 // Proj#5 (value returned from callnodes including allocations)
79 // CheckCastPP, CastPP
80 //
81 // The LoadP, Proj and CheckCastPP behave like variables assigned to only once.
82 // Only a Phi can have multiple assignments. Each input to a Phi is treated
83 // as an assignment to it.
84 //
85 // The following node types are JavaObject:
86 //
87 // phantom_object (general globally escaped object)
88 // Allocate
89 // AllocateArray
90 // Parm (for incoming arguments)
91 // CastX2P ("unsafe" operations)
92 // CreateEx
93 // ConP
94 // LoadKlass
95 // ThreadLocal
96 // CallStaticJava (which returns Object)
97 //
98 // AddP nodes are fields.
99 //
100 // After building the graph, a pass is made over the nodes, deleting deferred
101 // nodes and copying the edges from the target of the deferred edge to the
102 // source. This results in a graph with no deferred edges, only:
103 //
104 // LV -P> JO
105 // OF -P> JO (the object whose oop is stored in the field)
106 // JO -F> OF
107 //
108 // Then, for each node which is GlobalEscape, anything it could point to
109 // is marked GlobalEscape. Finally, for any node marked ArgEscape, anything
110 // it could point to is marked ArgEscape.
111 //
113 class Compile;
114 class Node;
115 class CallNode;
116 class PhiNode;
117 class PhaseTransform;
118 class PointsToNode;
119 class Type;
120 class TypePtr;
121 class VectorSet;
123 class JavaObjectNode;
124 class LocalVarNode;
125 class FieldNode;
126 class ArraycopyNode;
128 class ConnectionGraph;
130 // ConnectionGraph nodes
131 class PointsToNode : public ResourceObj {
132 GrowableArray<PointsToNode*> _edges; // List of nodes this node points to
133 GrowableArray<PointsToNode*> _uses; // List of nodes which point to this node
135 const u1 _type; // NodeType
136 u1 _flags; // NodeFlags
137 u1 _escape; // EscapeState of object
138 u1 _fields_escape; // EscapeState of object's fields
140 Node* const _node; // Ideal node corresponding to this PointsTo node.
141 const int _idx; // Cached ideal node's _idx
142 const uint _pidx; // Index of this node
144 public:
145 typedef enum {
146 UnknownType = 0,
147 JavaObject = 1,
148 LocalVar = 2,
149 Field = 3,
150 Arraycopy = 4
151 } NodeType;
153 typedef enum {
154 UnknownEscape = 0,
155 NoEscape = 1, // An object does not escape method or thread and it is
156 // not passed to call. It could be replaced with scalar.
157 ArgEscape = 2, // An object does not escape method or thread but it is
158 // passed as argument to call or referenced by argument
159 // and it does not escape during call.
160 GlobalEscape = 3 // An object escapes the method or thread.
161 } EscapeState;
163 typedef enum {
164 ScalarReplaceable = 1, // Not escaped object could be replaced with scalar
165 PointsToUnknown = 2, // Has edge to phantom_object
166 ArraycopySrc = 4, // Has edge from Arraycopy node
167 ArraycopyDst = 8 // Has edge to Arraycopy node
168 } NodeFlags;
171 inline PointsToNode(ConnectionGraph* CG, Node* n, EscapeState es, NodeType type);
173 uint pidx() const { return _pidx; }
175 Node* ideal_node() const { return _node; }
176 int idx() const { return _idx; }
178 bool is_JavaObject() const { return _type == (u1)JavaObject; }
179 bool is_LocalVar() const { return _type == (u1)LocalVar; }
180 bool is_Field() const { return _type == (u1)Field; }
181 bool is_Arraycopy() const { return _type == (u1)Arraycopy; }
183 JavaObjectNode* as_JavaObject() { assert(is_JavaObject(),""); return (JavaObjectNode*)this; }
184 LocalVarNode* as_LocalVar() { assert(is_LocalVar(),""); return (LocalVarNode*)this; }
185 FieldNode* as_Field() { assert(is_Field(),""); return (FieldNode*)this; }
186 ArraycopyNode* as_Arraycopy() { assert(is_Arraycopy(),""); return (ArraycopyNode*)this; }
188 EscapeState escape_state() const { return (EscapeState)_escape; }
189 void set_escape_state(EscapeState state) { _escape = (u1)state; }
191 EscapeState fields_escape_state() const { return (EscapeState)_fields_escape; }
192 void set_fields_escape_state(EscapeState state) { _fields_escape = (u1)state; }
194 bool has_unknown_ptr() const { return (_flags & PointsToUnknown) != 0; }
195 void set_has_unknown_ptr() { _flags |= PointsToUnknown; }
197 bool arraycopy_src() const { return (_flags & ArraycopySrc) != 0; }
198 void set_arraycopy_src() { _flags |= ArraycopySrc; }
199 bool arraycopy_dst() const { return (_flags & ArraycopyDst) != 0; }
200 void set_arraycopy_dst() { _flags |= ArraycopyDst; }
202 bool scalar_replaceable() const { return (_flags & ScalarReplaceable) != 0;}
203 void set_scalar_replaceable(bool v) {
204 if (v)
205 _flags |= ScalarReplaceable;
206 else
207 _flags &= ~ScalarReplaceable;
208 }
210 int edge_count() const { return _edges.length(); }
211 PointsToNode* edge(int e) const { return _edges.at(e); }
212 bool add_edge(PointsToNode* edge) { return _edges.append_if_missing(edge); }
214 int use_count() const { return _uses.length(); }
215 PointsToNode* use(int e) const { return _uses.at(e); }
216 bool add_use(PointsToNode* use) { return _uses.append_if_missing(use); }
218 // Mark base edge use to distinguish from stored value edge.
219 bool add_base_use(FieldNode* use) { return _uses.append_if_missing((PointsToNode*)((intptr_t)use + 1)); }
220 static bool is_base_use(PointsToNode* use) { return (((intptr_t)use) & 1); }
221 static PointsToNode* get_use_node(PointsToNode* use) { return (PointsToNode*)(((intptr_t)use) & ~1); }
223 // Return true if this node points to specified node or nodes it points to.
224 bool points_to(JavaObjectNode* ptn) const;
226 // Return true if this node points only to non-escaping allocations.
227 bool non_escaping_allocation();
229 // Return true if one node points to an other.
230 bool meet(PointsToNode* ptn);
232 #ifndef PRODUCT
233 NodeType node_type() const { return (NodeType)_type;}
234 void dump(bool print_state=true) const;
235 #endif
237 };
239 class LocalVarNode: public PointsToNode {
240 public:
241 LocalVarNode(ConnectionGraph *CG, Node* n, EscapeState es):
242 PointsToNode(CG, n, es, LocalVar) {}
243 };
245 class JavaObjectNode: public PointsToNode {
246 public:
247 JavaObjectNode(ConnectionGraph *CG, Node* n, EscapeState es):
248 PointsToNode(CG, n, es, JavaObject) {
249 if (es > NoEscape)
250 set_scalar_replaceable(false);
251 }
252 };
254 class FieldNode: public PointsToNode {
255 GrowableArray<PointsToNode*> _bases; // List of JavaObject nodes which point to this node
256 const int _offset; // Field's offset.
257 const bool _is_oop; // Field points to object
258 bool _has_unknown_base; // Has phantom_object base
259 public:
260 FieldNode(ConnectionGraph *CG, Node* n, EscapeState es, int offs, bool is_oop):
261 PointsToNode(CG, n, es, Field),
262 _offset(offs), _is_oop(is_oop),
263 _has_unknown_base(false) {}
265 int offset() const { return _offset;}
266 bool is_oop() const { return _is_oop;}
267 bool has_unknown_base() const { return _has_unknown_base; }
268 void set_has_unknown_base() { _has_unknown_base = true; }
270 int base_count() const { return _bases.length(); }
271 PointsToNode* base(int e) const { return _bases.at(e); }
272 bool add_base(PointsToNode* base) { return _bases.append_if_missing(base); }
273 #ifdef ASSERT
274 // Return true if bases points to this java object.
275 bool has_base(JavaObjectNode* ptn) const;
276 #endif
278 };
280 class ArraycopyNode: public PointsToNode {
281 public:
282 ArraycopyNode(ConnectionGraph *CG, Node* n, EscapeState es):
283 PointsToNode(CG, n, es, Arraycopy) {}
284 };
286 // Iterators for PointsTo node's edges:
287 // for (EdgeIterator i(n); i.has_next(); i.next()) {
288 // PointsToNode* u = i.get();
289 class PointsToIterator: public StackObj {
290 protected:
291 const PointsToNode* node;
292 const int cnt;
293 int i;
294 public:
295 inline PointsToIterator(const PointsToNode* n, int cnt) : node(n), cnt(cnt), i(0) { }
296 inline bool has_next() const { return i < cnt; }
297 inline void next() { i++; }
298 PointsToNode* get() const { ShouldNotCallThis(); return NULL; }
299 };
301 class EdgeIterator: public PointsToIterator {
302 public:
303 inline EdgeIterator(const PointsToNode* n) : PointsToIterator(n, n->edge_count()) { }
304 inline PointsToNode* get() const { return node->edge(i); }
305 };
307 class UseIterator: public PointsToIterator {
308 public:
309 inline UseIterator(const PointsToNode* n) : PointsToIterator(n, n->use_count()) { }
310 inline PointsToNode* get() const { return node->use(i); }
311 };
313 class BaseIterator: public PointsToIterator {
314 public:
315 inline BaseIterator(const FieldNode* n) : PointsToIterator(n, n->base_count()) { }
316 inline PointsToNode* get() const { return ((PointsToNode*)node)->as_Field()->base(i); }
317 };
320 class ConnectionGraph: public ResourceObj {
321 friend class PointsToNode;
322 private:
323 GrowableArray<PointsToNode*> _nodes; // Map from ideal nodes to
324 // ConnectionGraph nodes.
326 GrowableArray<PointsToNode*> _worklist; // Nodes to be processed
327 VectorSet _in_worklist;
328 uint _next_pidx;
330 bool _collecting; // Indicates whether escape information
331 // is still being collected. If false,
332 // no new nodes will be processed.
334 bool _verify; // verify graph
336 JavaObjectNode* phantom_obj; // Unknown object
337 JavaObjectNode* null_obj;
338 Node* _pcmp_neq; // ConI(#CC_GT)
339 Node* _pcmp_eq; // ConI(#CC_EQ)
341 Compile* _compile; // Compile object for current compilation
342 PhaseIterGVN* _igvn; // Value numbering
344 Unique_Node_List ideal_nodes; // Used by CG construction and types splitting.
346 // Address of an element in _nodes. Used when the element is to be modified
347 PointsToNode* ptnode_adr(int idx) const {
348 // There should be no new ideal nodes during ConnectionGraph build,
349 // growableArray::at() will throw assert otherwise.
350 return _nodes.at(idx);
351 }
352 uint nodes_size() const { return _nodes.length(); }
354 uint next_pidx() { return _next_pidx++; }
356 // Add nodes to ConnectionGraph.
357 void add_local_var(Node* n, PointsToNode::EscapeState es);
358 void add_java_object(Node* n, PointsToNode::EscapeState es);
359 void add_field(Node* n, PointsToNode::EscapeState es, int offset);
360 void add_arraycopy(Node* n, PointsToNode::EscapeState es, PointsToNode* src, PointsToNode* dst);
362 // Compute the escape state for arguments to a call.
363 void process_call_arguments(CallNode *call);
365 // Add PointsToNode node corresponding to a call
366 void add_call_node(CallNode* call);
368 // Map ideal node to existing PointsTo node (usually phantom_object).
369 void map_ideal_node(Node *n, PointsToNode* ptn) {
370 assert(ptn != NULL, "only existing PointsTo node");
371 _nodes.at_put(n->_idx, ptn);
372 }
374 // Utility function for nodes that load an object
375 void add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist);
376 // Create PointsToNode node and add it to Connection Graph.
377 void add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist);
379 // Add final simple edges to graph.
380 void add_final_edges(Node *n);
382 // Finish Graph construction.
383 bool complete_connection_graph(GrowableArray<PointsToNode*>& ptnodes_worklist,
384 GrowableArray<JavaObjectNode*>& non_escaped_worklist,
385 GrowableArray<JavaObjectNode*>& java_objects_worklist,
386 GrowableArray<FieldNode*>& oop_fields_worklist);
388 #ifdef ASSERT
389 void verify_connection_graph(GrowableArray<PointsToNode*>& ptnodes_worklist,
390 GrowableArray<JavaObjectNode*>& non_escaped_worklist,
391 GrowableArray<JavaObjectNode*>& java_objects_worklist,
392 GrowableArray<Node*>& addp_worklist);
393 #endif
395 // Add all references to this JavaObject node.
396 int add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist);
398 // Put node on worklist if it is (or was) not there.
399 inline void add_to_worklist(PointsToNode* pt) {
400 PointsToNode* ptf = pt;
401 uint pidx_bias = 0;
402 if (PointsToNode::is_base_use(pt)) {
403 // Create a separate entry in _in_worklist for a marked base edge
404 // because _worklist may have an entry for a normal edge pointing
405 // to the same node. To separate them use _next_pidx as bias.
406 ptf = PointsToNode::get_use_node(pt)->as_Field();
407 pidx_bias = _next_pidx;
408 }
409 if (!_in_worklist.test_set(ptf->pidx() + pidx_bias)) {
410 _worklist.append(pt);
411 }
412 }
414 // Put on worklist all uses of this node.
415 inline void add_uses_to_worklist(PointsToNode* pt) {
416 for (UseIterator i(pt); i.has_next(); i.next()) {
417 add_to_worklist(i.get());
418 }
419 }
421 // Put on worklist all field's uses and related field nodes.
422 void add_field_uses_to_worklist(FieldNode* field);
424 // Put on worklist all related field nodes.
425 void add_fields_to_worklist(FieldNode* field, PointsToNode* base);
427 // Find fields which have unknown value.
428 int find_field_value(FieldNode* field);
430 // Find fields initializing values for allocations.
431 int find_init_values(JavaObjectNode* ptn, PointsToNode* init_val, PhaseTransform* phase);
433 // Set the escape state of an object and its fields.
434 void set_escape_state(PointsToNode* ptn, PointsToNode::EscapeState esc) {
435 // Don't change non-escaping state of NULL pointer.
436 if (ptn != null_obj) {
437 if (ptn->escape_state() < esc)
438 ptn->set_escape_state(esc);
439 if (ptn->fields_escape_state() < esc)
440 ptn->set_fields_escape_state(esc);
441 }
442 }
443 void set_fields_escape_state(PointsToNode* ptn, PointsToNode::EscapeState esc) {
444 // Don't change non-escaping state of NULL pointer.
445 if (ptn != null_obj) {
446 if (ptn->fields_escape_state() < esc)
447 ptn->set_fields_escape_state(esc);
448 }
449 }
451 // Propagate GlobalEscape and ArgEscape escape states to all nodes
452 // and check that we still have non-escaping java objects.
453 bool find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
454 GrowableArray<JavaObjectNode*>& non_escaped_worklist);
456 // Adjust scalar_replaceable state after Connection Graph is built.
457 void adjust_scalar_replaceable_state(JavaObjectNode* jobj);
459 // Optimize ideal graph.
460 void optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
461 GrowableArray<Node*>& storestore_worklist);
462 // Optimize objects compare.
463 Node* optimize_ptr_compare(Node* n);
465 // Returns unique corresponding java object or NULL.
466 JavaObjectNode* unique_java_object(Node *n);
468 // Add an edge of the specified type pointing to the specified target.
469 bool add_edge(PointsToNode* from, PointsToNode* to) {
470 assert(!from->is_Field() || from->as_Field()->is_oop(), "sanity");
472 if (to == phantom_obj) {
473 if (from->has_unknown_ptr()) {
474 return false; // already points to phantom_obj
475 }
476 from->set_has_unknown_ptr();
477 }
479 bool is_new = from->add_edge(to);
480 assert(to != phantom_obj || is_new, "sanity");
481 if (is_new) { // New edge?
482 assert(!_verify, "graph is incomplete");
483 is_new = to->add_use(from);
484 assert(is_new, "use should be also new");
485 }
486 return is_new;
487 }
489 // Add an edge from Field node to its base and back.
490 bool add_base(FieldNode* from, PointsToNode* to) {
491 assert(!to->is_Arraycopy(), "sanity");
492 if (to == phantom_obj) {
493 if (from->has_unknown_base()) {
494 return false; // already has phantom_obj base
495 }
496 from->set_has_unknown_base();
497 }
498 bool is_new = from->add_base(to);
499 assert(to != phantom_obj || is_new, "sanity");
500 if (is_new) { // New edge?
501 assert(!_verify, "graph is incomplete");
502 if (to == null_obj)
503 return is_new; // Don't add fields to NULL pointer.
504 if (to->is_JavaObject()) {
505 is_new = to->add_edge(from);
506 } else {
507 is_new = to->add_base_use(from);
508 }
509 assert(is_new, "use should be also new");
510 }
511 return is_new;
512 }
514 // Add LocalVar node and edge if possible
515 void add_local_var_and_edge(Node* n, PointsToNode::EscapeState es, Node* to,
516 Unique_Node_List *delayed_worklist) {
517 PointsToNode* ptn = ptnode_adr(to->_idx);
518 if (delayed_worklist != NULL) { // First iteration of CG construction
519 add_local_var(n, es);
520 if (ptn == NULL) {
521 delayed_worklist->push(n);
522 return; // Process it later.
523 }
524 } else {
525 assert(ptn != NULL, "node should be registered");
526 }
527 add_edge(ptnode_adr(n->_idx), ptn);
528 }
529 // Helper functions
530 bool is_oop_field(Node* n, int offset, bool* unsafe);
531 static Node* get_addp_base(Node *addp);
532 static Node* find_second_addp(Node* addp, Node* n);
533 // offset of a field reference
534 int address_offset(Node* adr, PhaseTransform *phase);
537 // Propagate unique types created for unescaped allocated objects
538 // through the graph
539 void split_unique_types(GrowableArray<Node *> &alloc_worklist);
541 // Helper methods for unique types split.
542 bool split_AddP(Node *addp, Node *base);
544 PhiNode *create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, bool &new_created);
545 PhiNode *split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist);
547 void move_inst_mem(Node* n, GrowableArray<PhiNode *> &orig_phis);
548 Node* find_inst_mem(Node* mem, int alias_idx,GrowableArray<PhiNode *> &orig_phi_worklist);
549 Node* step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop);
552 GrowableArray<MergeMemNode*> _mergemem_worklist; // List of all MergeMem nodes
554 Node_Array _node_map; // used for bookeeping during type splitting
555 // Used for the following purposes:
556 // Memory Phi - most recent unique Phi split out
557 // from this Phi
558 // MemNode - new memory input for this node
559 // ChecCastPP - allocation that this is a cast of
560 // allocation - CheckCastPP of the allocation
562 // manage entries in _node_map
564 void set_map(Node* from, Node* to) {
565 ideal_nodes.push(from);
566 _node_map.map(from->_idx, to);
567 }
569 Node* get_map(int idx) { return _node_map[idx]; }
571 PhiNode* get_map_phi(int idx) {
572 Node* phi = _node_map[idx];
573 return (phi == NULL) ? NULL : phi->as_Phi();
574 }
576 // Notify optimizer that a node has been modified
577 void record_for_optimizer(Node *n) {
578 _igvn->_worklist.push(n);
579 _igvn->add_users_to_worklist(n);
580 }
582 // Compute the escape information
583 bool compute_escape();
585 public:
586 ConnectionGraph(Compile *C, PhaseIterGVN *igvn);
588 // Check for non-escaping candidates
589 static bool has_candidates(Compile *C);
591 // Perform escape analysis
592 static void do_analysis(Compile *C, PhaseIterGVN *igvn);
594 bool not_global_escape(Node *n);
596 #ifndef PRODUCT
597 void dump(GrowableArray<PointsToNode*>& ptnodes_worklist);
598 #endif
599 };
601 inline PointsToNode::PointsToNode(ConnectionGraph *CG, Node* n, EscapeState es, NodeType type):
602 _edges(CG->_compile->comp_arena(), 2, 0, NULL),
603 _uses (CG->_compile->comp_arena(), 2, 0, NULL),
604 _node(n),
605 _idx(n->_idx),
606 _pidx(CG->next_pidx()),
607 _type((u1)type),
608 _escape((u1)es),
609 _fields_escape((u1)es),
610 _flags(ScalarReplaceable) {
611 assert(n != NULL && es != UnknownEscape, "sanity");
612 }
614 #endif // SHARE_VM_OPTO_ESCAPE_HPP