1/*
2 * Copyright (C) 2011-2013, 2016 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#pragma once
30
31#include "ConcurrentJSLock.h"
32#include "SpeculatedType.h"
33#include "Structure.h"
34#include <wtf/PrintStream.h>
35#include <wtf/StringPrintStream.h>
36
37namespace JSC {
38
39template<unsigned numberOfBucketsArgument>
40struct ValueProfileBase {
41 static const unsigned numberOfBuckets = numberOfBucketsArgument;
42 static const unsigned numberOfSpecFailBuckets = 1;
43 static const unsigned bucketIndexMask = numberOfBuckets - 1;
44 static const unsigned totalNumberOfBuckets = numberOfBuckets + numberOfSpecFailBuckets;
45
46 ValueProfileBase()
47 : m_bytecodeOffset(-1)
48 {
49 for (unsigned i = 0; i < totalNumberOfBuckets; ++i)
50 m_buckets[i] = JSValue::encode(JSValue());
51 }
52
53 ValueProfileBase(int bytecodeOffset)
54 : m_bytecodeOffset(bytecodeOffset)
55 {
56 for (unsigned i = 0; i < totalNumberOfBuckets; ++i)
57 m_buckets[i] = JSValue::encode(JSValue());
58 }
59
60 EncodedJSValue* specFailBucket(unsigned i)
61 {
62 ASSERT(numberOfBuckets + i < totalNumberOfBuckets);
63 return m_buckets + numberOfBuckets + i;
64 }
65
66 const ClassInfo* classInfo(unsigned bucket) const
67 {
68 JSValue value = JSValue::decode(m_buckets[bucket]);
69 if (!!value) {
70 if (!value.isCell())
71 return 0;
72 return value.asCell()->structure()->classInfo();
73 }
74 return 0;
75 }
76
77 unsigned numberOfSamples() const
78 {
79 unsigned result = 0;
80 for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
81 if (!!JSValue::decode(m_buckets[i]))
82 result++;
83 }
84 return result;
85 }
86
87 unsigned totalNumberOfSamples() const
88 {
89 return numberOfSamples() + m_numberOfSamplesInPrediction;
90 }
91
92 bool isLive() const
93 {
94 for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
95 if (!!JSValue::decode(m_buckets[i]))
96 return true;
97 }
98 return false;
99 }
100
101 CString briefDescription(const ConcurrentJSLocker& locker)
102 {
103 computeUpdatedPrediction(locker);
104
105 StringPrintStream out;
106 out.print("predicting ", SpeculationDump(m_prediction));
107 return out.toCString();
108 }
109
110 void dump(PrintStream& out)
111 {
112 out.print("samples = ", totalNumberOfSamples(), " prediction = ", SpeculationDump(m_prediction));
113 bool first = true;
114 for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
115 JSValue value = JSValue::decode(m_buckets[i]);
116 if (!!value) {
117 if (first) {
118 out.printf(": ");
119 first = false;
120 } else
121 out.printf(", ");
122 out.print(value);
123 }
124 }
125 }
126
127 // Updates the prediction and returns the new one. Never call this from any thread
128 // that isn't executing the code.
129 SpeculatedType computeUpdatedPrediction(const ConcurrentJSLocker&)
130 {
131 for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
132 JSValue value = JSValue::decode(m_buckets[i]);
133 if (!value)
134 continue;
135
136 m_numberOfSamplesInPrediction++;
137 mergeSpeculation(m_prediction, speculationFromValue(value));
138
139 m_buckets[i] = JSValue::encode(JSValue());
140 }
141
142 return m_prediction;
143 }
144
145 int m_bytecodeOffset; // -1 for prologue
146 unsigned m_numberOfSamplesInPrediction { 0 };
147
148 SpeculatedType m_prediction { SpecNone };
149
150 EncodedJSValue m_buckets[totalNumberOfBuckets];
151};
152
153struct MinimalValueProfile : public ValueProfileBase<0> {
154 MinimalValueProfile(): ValueProfileBase<0>() { }
155 MinimalValueProfile(int bytecodeOffset): ValueProfileBase<0>(bytecodeOffset) { }
156};
157
158template<unsigned logNumberOfBucketsArgument>
159struct ValueProfileWithLogNumberOfBuckets : public ValueProfileBase<1 << logNumberOfBucketsArgument> {
160 static const unsigned logNumberOfBuckets = logNumberOfBucketsArgument;
161
162 ValueProfileWithLogNumberOfBuckets()
163 : ValueProfileBase<1 << logNumberOfBucketsArgument>()
164 {
165 }
166 ValueProfileWithLogNumberOfBuckets(int bytecodeOffset)
167 : ValueProfileBase<1 << logNumberOfBucketsArgument>(bytecodeOffset)
168 {
169 }
170};
171
172struct ValueProfile : public ValueProfileWithLogNumberOfBuckets<0> {
173 ValueProfile() : ValueProfileWithLogNumberOfBuckets<0>() { }
174 ValueProfile(int bytecodeOffset) : ValueProfileWithLogNumberOfBuckets<0>(bytecodeOffset) { }
175};
176
177template<typename T>
178inline int getValueProfileBytecodeOffset(T* valueProfile)
179{
180 return valueProfile->m_bytecodeOffset;
181}
182
183// This is a mini value profile to catch pathologies. It is a counter that gets
184// incremented when we take the slow path on any instruction.
185struct RareCaseProfile {
186 RareCaseProfile(int bytecodeOffset)
187 : m_bytecodeOffset(bytecodeOffset)
188 , m_counter(0)
189 {
190 }
191
192 int m_bytecodeOffset;
193 uint32_t m_counter;
194};
195
196inline int getRareCaseProfileBytecodeOffset(RareCaseProfile* rareCaseProfile)
197{
198 return rareCaseProfile->m_bytecodeOffset;
199}
200
201struct ValueProfileAndOperand {
202 ValueProfile m_profile;
203 int m_operand;
204};
205
206struct ValueProfileAndOperandBuffer {
207 ValueProfileAndOperandBuffer(unsigned size)
208 : m_size(size)
209 {
210 // FIXME: ValueProfile has more stuff than we need. We could optimize these value profiles
211 // to be more space efficient.
212 // https://bugs.webkit.org/show_bug.cgi?id=175413
213 m_buffer = MallocPtr<ValueProfileAndOperand>::malloc(m_size * sizeof(ValueProfileAndOperand));
214 for (unsigned i = 0; i < m_size; ++i)
215 new (&m_buffer.get()[i]) ValueProfileAndOperand();
216 }
217
218 ~ValueProfileAndOperandBuffer()
219 {
220 for (unsigned i = 0; i < m_size; ++i)
221 m_buffer.get()[i].~ValueProfileAndOperand();
222 }
223
224 template <typename Function>
225 void forEach(Function function)
226 {
227 for (unsigned i = 0; i < m_size; ++i)
228 function(m_buffer.get()[i]);
229 }
230
231 unsigned m_size;
232 MallocPtr<ValueProfileAndOperand> m_buffer;
233};
234
235} // namespace JSC
236