1 /*
2 * Copyright (c) 2012, 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.
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23 */
24
25 #ifndef SHARE_C1_C1_RANGECHECKELIMINATION_HPP
26 #define SHARE_C1_C1_RANGECHECKELIMINATION_HPP
27
28 #include "c1/c1_Instruction.hpp"
29
30 // Base class for range check elimination
31 class RangeCheckElimination : AllStatic {
32 public:
33 static void eliminate(IR *ir);
34 };
35
36 // Implementation
37 class RangeCheckEliminator {
38 private:
39 int _number_of_instructions;
40 bool _optimistic; // Insert predicates and deoptimize when they fail
41 IR *_ir;
42
43 typedef GrowableArray<BlockBegin*> BlockBeginList;
44 typedef GrowableArray<int> IntegerStack;
45
46 #ifdef ASSERT
47 class Verification : public BlockClosure {
48 // RangeCheckEliminator::Verification should never get instatiated on the heap.
49 private:
50 void* operator new(size_t size) throw();
51 void* operator new[](size_t size) throw();
52 void operator delete(void* p) { ShouldNotReachHere(); }
53 void operator delete[](void* p) { ShouldNotReachHere(); }
54
55 bool can_reach(BlockBegin *start, BlockBegin *end, BlockBegin *dont_use = nullptr);
56 bool dominates(BlockBegin *dominator, BlockBegin *block);
57 bool is_backbranch_from_xhandler(BlockBegin* block);
58
59 IR *_ir;
60 boolArray _used;
61 BlockBeginList _current;
62 BlockBeginList _successors;
63
64 public:
65 Verification(IR *ir);
66 virtual void block_do(BlockBegin *block);
67 };
68 #endif
69
70 public:
71 // Bounds for an instruction in the form x + c which c integer
72 // constant and x another instruction
73 class Bound : public CompilationResourceObj {
74 private:
75 int _upper;
76 Value _upper_instr;
77 int _lower;
78 Value _lower_instr;
79
80 public:
81 Bound();
82 Bound(Value v);
83 Bound(Instruction::Condition cond, Value v, int constant = 0);
84 Bound(int lower, Value lower_instr, int upper, Value upper_instr);
85 ~Bound();
86
87 #ifdef ASSERT
88 void add_assertion(Instruction *instruction, Instruction *position, int i, Value instr, Instruction::Condition cond);
89 #endif
90 int upper();
91 Value upper_instr();
92 int lower();
93 Value lower_instr();
94 void print();
95 bool check_no_overflow(int const_value);
96 void or_op(Bound *b);
97 void and_op(Bound *b);
98 bool has_upper();
99 bool has_lower();
100 bool is_smaller(Bound *b);
101 void remove_upper();
102 void remove_lower();
103 Bound *copy();
104 };
105
106
107 class Visitor : public InstructionVisitor {
108 private:
109 Bound *_bound;
110 RangeCheckEliminator *_rce;
111
112 public:
113 void set_range_check_eliminator(RangeCheckEliminator *rce) { _rce = rce; }
114 Bound *bound() const { return _bound; }
115 void clear_bound() { _bound = nullptr; }
116
117 protected:
118 // visitor functions
119 void do_Constant (Constant* x);
120 void do_IfOp (IfOp* x);
121 void do_LogicOp (LogicOp* x);
122 void do_ArithmeticOp (ArithmeticOp* x);
123 void do_Phi (Phi* x);
124
125 void do_StoreField (StoreField* x) { /* nothing to do */ };
126 void do_StoreIndexed (StoreIndexed* x) { /* nothing to do */ };
127 void do_MonitorEnter (MonitorEnter* x) { /* nothing to do */ };
128 void do_MonitorExit (MonitorExit* x) { /* nothing to do */ };
129 void do_Invoke (Invoke* x) { /* nothing to do */ };
130 void do_Intrinsic (Intrinsic* x) { /* nothing to do */ };
131 void do_Local (Local* x) { /* nothing to do */ };
132 void do_LoadField (LoadField* x) { /* nothing to do */ };
133 void do_ArrayLength (ArrayLength* x) { /* nothing to do */ };
134 void do_LoadIndexed (LoadIndexed* x) { /* nothing to do */ };
135 void do_NegateOp (NegateOp* x) { /* nothing to do */ };
136 void do_ShiftOp (ShiftOp* x) { /* nothing to do */ };
137 void do_CompareOp (CompareOp* x) { /* nothing to do */ };
138 void do_Convert (Convert* x) { /* nothing to do */ };
139 void do_NullCheck (NullCheck* x) { /* nothing to do */ };
140 void do_TypeCast (TypeCast* x) { /* nothing to do */ };
141 void do_NewInstance (NewInstance* x) { /* nothing to do */ };
142 void do_NewTypeArray (NewTypeArray* x) { /* nothing to do */ };
143 void do_NewObjectArray (NewObjectArray* x) { /* nothing to do */ };
144 void do_NewMultiArray (NewMultiArray* x) { /* nothing to do */ };
145 void do_CheckCast (CheckCast* x) { /* nothing to do */ };
146 void do_InstanceOf (InstanceOf* x) { /* nothing to do */ };
147 void do_BlockBegin (BlockBegin* x) { /* nothing to do */ };
148 void do_Goto (Goto* x) { /* nothing to do */ };
149 void do_If (If* x) { /* nothing to do */ };
150 void do_TableSwitch (TableSwitch* x) { /* nothing to do */ };
151 void do_LookupSwitch (LookupSwitch* x) { /* nothing to do */ };
152 void do_Return (Return* x) { /* nothing to do */ };
153 void do_Throw (Throw* x) { /* nothing to do */ };
154 void do_Base (Base* x) { /* nothing to do */ };
155 void do_OsrEntry (OsrEntry* x) { /* nothing to do */ };
156 void do_ExceptionObject(ExceptionObject* x) { /* nothing to do */ };
157 void do_RoundFP (RoundFP* x) { /* nothing to do */ };
158 void do_UnsafePut (UnsafePut* x) { /* nothing to do */ };
159 void do_UnsafeGet (UnsafeGet* x) { /* nothing to do */ };
160 void do_UnsafeGetAndSet(UnsafeGetAndSet* x) { /* nothing to do */ };
161 void do_ProfileCall (ProfileCall* x) { /* nothing to do */ };
162 void do_ProfileReturnType (ProfileReturnType* x) { /* nothing to do */ };
163 void do_ProfileInvoke (ProfileInvoke* x) { /* nothing to do */ };
164 void do_RuntimeCall (RuntimeCall* x) { /* nothing to do */ };
165 void do_MemBar (MemBar* x) { /* nothing to do */ };
166 void do_RangeCheckPredicate(RangeCheckPredicate* x) { /* nothing to do */ };
167 #ifdef ASSERT
168 void do_Assert (Assert* x) { /* nothing to do */ };
169 #endif
170 };
171
172 #ifdef ASSERT
173 void add_assertions(Bound *bound, Instruction *instruction, Instruction *position);
174 #endif
175
176 typedef GrowableArray<Bound*> BoundStack;
177 typedef GrowableArray<BoundStack*> BoundMap;
178 typedef GrowableArray<AccessIndexed*> AccessIndexedList;
179 typedef GrowableArray<Instruction*> InstructionList;
180
181 class AccessIndexedInfo : public CompilationResourceObj {
182 public:
183 AccessIndexedList *_list;
184 int _min;
185 int _max;
186 };
187
188 typedef GrowableArray<AccessIndexedInfo*> AccessIndexedInfoArray;
189 BoundMap _bounds; // Mapping from Instruction's id to current bound
190 AccessIndexedInfoArray _access_indexed_info; // Mapping from Instruction's id to AccessIndexedInfo for in block motion
191 Visitor _visitor;
192
193 public:
194 RangeCheckEliminator(IR *ir);
195
196 IR *ir() const { return _ir; }
197
198 // Pass over the dominator tree to identify blocks where there's an oppportunity for optimization
199 bool set_process_block_flags(BlockBegin *block);
200 // The core of the optimization work: pass over the dominator tree
201 // to propagate bound information, insert predicate out of loops,
202 // eliminate bound checks when possible and perform in block motion
203 void calc_bounds(BlockBegin *block, BlockBegin *loop_header);
204 // reorder bound checks within a block in order to eliminate some of them
205 void in_block_motion(BlockBegin *block, AccessIndexedList &accessIndexed, InstructionList &arrays);
206
207 // update/access current bound
208 void update_bound(IntegerStack &pushed, Value v, Instruction::Condition cond, Value value, int constant);
209 void update_bound(IntegerStack &pushed, Value v, Bound *bound);
210 Bound *get_bound(Value v);
211
212 bool loop_invariant(BlockBegin *loop_header, Instruction *instruction); // check for loop invariance
213 void add_access_indexed_info(InstructionList &indices, int i, Value instruction, AccessIndexed *ai); // record indexed access for in block motion
214 void remove_range_check(AccessIndexed *ai); // Mark this instructions as not needing a range check
215 void add_if_condition(IntegerStack &pushed, Value x, Value y, Instruction::Condition condition); // Update bound for an If
216 bool in_array_bound(Bound *bound, Value array); // Check whether bound is known to fall within array
217
218 // helper functions to work with predicates
219 Instruction* insert_after(Instruction* insert_position, Instruction* instr, int bci);
220 Instruction* predicate(Instruction* left, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci=-1);
221 Instruction* predicate_cmp_with_const(Instruction* instr, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci=1);
222 Instruction* predicate_add(Instruction* left, int left_const, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci=-1);
223 Instruction* predicate_add_cmp_with_const(Instruction* left, int left_const, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci=-1);
224
225 void insert_deoptimization(ValueStack *state, Instruction *insert_position, Instruction *array_instr, // Add predicate
226 Instruction *length_instruction, Instruction *lower_instr, int lower,
227 Instruction *upper_instr, int upper, AccessIndexed *ai);
228 bool is_ok_for_deoptimization(Instruction *insert_position, Instruction *array_instr, // Can we safely add a predicate?
229 Instruction *length_instr, Instruction *lower_instr,
230 int lower, Instruction *upper_instr, int upper);
231 void process_if(IntegerStack &pushed, BlockBegin *block, If *cond); // process If Instruction
232 void process_access_indexed(BlockBegin *loop_header, BlockBegin *block, AccessIndexed *ai); // process indexed access
233
234 void dump_condition_stack(BlockBegin *cur_block);
235 static void print_statistics();
236 };
237
238 #endif // SHARE_C1_C1_RANGECHECKELIMINATION_HPP