1 /*
2 * Copyright (c) 1999, 2023, 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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_C1_C1_VALUEMAP_HPP
26 #define SHARE_C1_C1_VALUEMAP_HPP
27
28 #include "c1/c1_Instruction.hpp"
29 #include "c1/c1_ValueSet.hpp"
30 #include "memory/allocation.hpp"
31
32 class ValueMapEntry: public CompilationResourceObj {
33 private:
34 intx _hash;
35 Value _value;
36 int _nesting;
37 ValueMapEntry* _next;
38
39 public:
40 ValueMapEntry(intx hash, Value value, int nesting, ValueMapEntry* next)
41 : _hash(hash)
42 , _value(value)
43 , _nesting(nesting)
44 , _next(next)
45 {
46 }
47
48 intx hash() { return _hash; }
49 Value value() { return _value; }
50 int nesting() { return _nesting; }
51 ValueMapEntry* next() { return _next; }
52
53 void set_next(ValueMapEntry* next) { _next = next; }
54 };
55
56 typedef GrowableArray<ValueMapEntry*> ValueMapEntryArray;
57 typedef GrowableArray<ValueMapEntry*> ValueMapEntryList;
58
59 // ValueMap implements nested hash tables for value numbering. It
60 // maintains a set _killed_values which represents the instructions
61 // which have been killed so far and an array of linked lists of
62 // ValueMapEntries names _entries. Each ValueMapEntry has a nesting
63 // which indicates what ValueMap nesting it belongs to. Higher
64 // nesting values are always before lower values in the linked list.
65 // This allows cloning of parent ValueMaps by simply copying the heads
66 // of the list. _entry_count represents the number of reachable
67 // entries in the ValueMap. A ValueMap is only allowed to mutate
68 // ValueMapEntries with the same nesting level. Adding or removing
69 // entries at the current nesting level requires updating
70 // _entry_count. Elements in the parent's list that get killed can be
71 // skipped if they are at the head of the list by simply moving to the
72 // next element in the list and decrementing _entry_count.
73
74 class ValueMap: public CompilationResourceObj {
75 private:
76 int _nesting;
77 ValueMapEntryArray _entries;
78 ValueSet _killed_values;
79 int _entry_count;
80
81 int nesting() { return _nesting; }
82 bool is_local_value_numbering() { return _nesting == 0; }
83 bool is_global_value_numbering() { return _nesting > 0; }
84
85 int entry_count() { return _entry_count; }
86 int size() { return _entries.length(); }
87 ValueMapEntry* entry_at(int i) { return _entries.at(i); }
88
89 // calculates the index of a hash value in a hash table of size n
90 int entry_index(intx hash, int n) { return (unsigned int)hash % n; }
91
92 // if entry_count > size_threshold, the size of the hash table is increased
93 int size_threshold() { return size(); }
94
95 // management of the killed-bitset for global value numbering
96 void kill_value(Value v) { if (is_global_value_numbering()) _killed_values.put(v); }
97 bool is_killed(Value v) { if (is_global_value_numbering()) return _killed_values.contains(v); else return false; }
98
99 // helper functions
100 void increase_table_size();
101
102 #ifndef PRODUCT
103 static int _number_of_finds;
104 static int _number_of_hits;
105 static int _number_of_kills;
106 #endif // PRODUCT
107
108 public:
109 // creation
110 ValueMap(); // empty value map
111 ValueMap(ValueMap* old); // value map with increased nesting
112
113 // manipulation
114 Value find_insert(Value x);
115
116 void kill_memory();
117 void kill_field(ciField* field, bool all_offsets);
118 void kill_array(ValueType* type);
119 void kill_map(ValueMap* map);
120 void kill_all();
121
122 #ifndef PRODUCT
123 // debugging/printing
124 void print();
125
126 static void reset_statistics();
127 static void print_statistics();
128 #endif
129 };
130
131 typedef GrowableArray<ValueMap*> ValueMapArray;
132
133 class ValueNumberingVisitor: public InstructionVisitor {
134 protected:
135 // called by visitor functions for instructions that kill values
136 virtual void kill_memory() = 0;
137 virtual void kill_field(ciField* field, bool all_offsets) = 0;
138 virtual void kill_array(ValueType* type) = 0;
139
140 // visitor functions
141 void do_StoreField (StoreField* x) {
142 if (x->is_init_point() || // putstatic is an initialization point so treat it as a wide kill
143 // This is actually too strict and the JMM doesn't require
144 // this in all cases (e.g. load a; volatile store b; load a)
145 // but possible future optimizations might require this.
146 x->field()->is_volatile()) {
147 kill_memory();
148 } else {
149 kill_field(x->field(), x->needs_patching());
150 if (x->enclosing_field() != nullptr) {
151 kill_field(x->enclosing_field(), true);
152 }
153 }
154 }
155 void do_StoreIndexed (StoreIndexed* x) { kill_array(x->type()); }
156 void do_MonitorEnter (MonitorEnter* x) { kill_memory(); }
157 void do_MonitorExit (MonitorExit* x) { kill_memory(); }
158 void do_Invoke (Invoke* x) { kill_memory(); }
159 void do_UnsafePut (UnsafePut* x) { kill_memory(); }
160 void do_UnsafeGetAndSet(UnsafeGetAndSet* x) { kill_memory(); }
161 void do_UnsafeGet (UnsafeGet* x) {
162 if (x->is_volatile()) { // the JMM requires this
163 kill_memory();
164 }
165 }
166 void do_Intrinsic (Intrinsic* x) { if (!x->preserves_state()) kill_memory(); }
167
168 void do_Phi (Phi* x) { /* nothing to do */ }
169 void do_Local (Local* x) { /* nothing to do */ }
170 void do_Constant (Constant* x) {
171 if (x->kills_memory()) {
172 assert(x->can_trap(), "already linked");
173 kill_memory();
174 }
175 }
176 void do_LoadField (LoadField* x) {
177 if (x->is_init_point() || // getstatic is an initialization point so treat it as a wide kill
178 x->field()->is_volatile()) { // the JMM requires this
179 kill_memory();
180 }
181 }
182 void do_ArrayLength (ArrayLength* x) { /* nothing to do */ }
183 void do_LoadIndexed (LoadIndexed* x) { /* nothing to do */ }
184 void do_NegateOp (NegateOp* x) { /* nothing to do */ }
185 void do_ArithmeticOp (ArithmeticOp* x) { /* nothing to do */ }
186 void do_ShiftOp (ShiftOp* x) { /* nothing to do */ }
187 void do_LogicOp (LogicOp* x) { /* nothing to do */ }
188 void do_CompareOp (CompareOp* x) { /* nothing to do */ }
189 void do_IfOp (IfOp* x) { /* nothing to do */ }
190 void do_Convert (Convert* x) { /* nothing to do */ }
191 void do_NullCheck (NullCheck* x) { /* nothing to do */ }
192 void do_TypeCast (TypeCast* x) { /* nothing to do */ }
193 void do_NewInstance (NewInstance* x) { /* nothing to do */ }
194 void do_NewTypeArray (NewTypeArray* x) { /* nothing to do */ }
195 void do_NewObjectArray (NewObjectArray* x) { /* nothing to do */ }
196 void do_NewMultiArray (NewMultiArray* x) { /* nothing to do */ }
197 void do_CheckCast (CheckCast* x) { /* nothing to do */ }
198 void do_InstanceOf (InstanceOf* x) { /* nothing to do */ }
199 void do_BlockBegin (BlockBegin* x) { /* nothing to do */ }
200 void do_Goto (Goto* x) { /* nothing to do */ }
201 void do_If (If* x) { /* nothing to do */ }
202 void do_TableSwitch (TableSwitch* x) { /* nothing to do */ }
203 void do_LookupSwitch (LookupSwitch* x) { /* nothing to do */ }
204 void do_Return (Return* x) { /* nothing to do */ }
205 void do_Throw (Throw* x) { /* nothing to do */ }
206 void do_Base (Base* x) { /* nothing to do */ }
207 void do_OsrEntry (OsrEntry* x) { /* nothing to do */ }
208 void do_ExceptionObject(ExceptionObject* x) { /* nothing to do */ }
209 void do_RoundFP (RoundFP* x) { /* nothing to do */ }
210 void do_ProfileCall (ProfileCall* x) { /* nothing to do */ }
211 void do_ProfileReturnType (ProfileReturnType* x) { /* nothing to do */ }
212 void do_ProfileACmpTypes(ProfileACmpTypes* x) { /* nothing to do */ }
213 void do_ProfileInvoke (ProfileInvoke* x) { /* nothing to do */ };
214 void do_RuntimeCall (RuntimeCall* x) { /* nothing to do */ };
215 void do_MemBar (MemBar* x) { /* nothing to do */ };
216 void do_RangeCheckPredicate(RangeCheckPredicate* x) { /* nothing to do */ };
217 #ifdef ASSERT
218 void do_Assert (Assert* x) { /* nothing to do */ };
219 #endif
220 };
221
222
223 class ValueNumberingEffects: public ValueNumberingVisitor {
224 private:
225 ValueMap* _map;
226
227 public:
228 // implementation for abstract methods of ValueNumberingVisitor
229 void kill_memory() { _map->kill_memory(); }
230 void kill_field(ciField* field, bool all_offsets) { _map->kill_field(field, all_offsets); }
231 void kill_array(ValueType* type) { _map->kill_array(type); }
232
233 ValueNumberingEffects(ValueMap* map): _map(map) {}
234 };
235
236
237 class GlobalValueNumbering: public ValueNumberingVisitor {
238 private:
239 Compilation* _compilation; // compilation data
240 ValueMap* _current_map; // value map of current block
241 ValueMapArray _value_maps; // list of value maps for all blocks
242 ValueSet _processed_values; // marker for instructions that were already processed
243 bool _has_substitutions; // set to true when substitutions must be resolved
244
245 public:
246 // accessors
247 Compilation* compilation() const { return _compilation; }
248 ValueMap* current_map() { return _current_map; }
249 ValueMap* value_map_of(BlockBegin* block) { return _value_maps.at(block->linear_scan_number()); }
250 void set_value_map_of(BlockBegin* block, ValueMap* map) { assert(value_map_of(block) == nullptr, ""); _value_maps.at_put(block->linear_scan_number(), map); }
251
252 bool is_processed(Value v) { return _processed_values.contains(v); }
253 void set_processed(Value v) { _processed_values.put(v); }
254
255 // implementation for abstract methods of ValueNumberingVisitor
256 void kill_memory() { current_map()->kill_memory(); }
257 void kill_field(ciField* field, bool all_offsets) { current_map()->kill_field(field, all_offsets); }
258 void kill_array(ValueType* type) { current_map()->kill_array(type); }
259
260 // main entry point that performs global value numbering
261 GlobalValueNumbering(IR* ir);
262 void substitute(Instruction* instr); // substitute instruction if it is contained in current value map
263 };
264
265 #endif // SHARE_C1_C1_VALUEMAP_HPP