1 // Copyright 2011 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_SAFEPOINT_TABLE_H_ 29 #define V8_SAFEPOINT_TABLE_H_ 30 31 #include "allocation.h" 32 #include "heap.h" 33 #include "v8memory.h" 34 #include "zone.h" 35 36 namespace v8 { 37 namespace internal { 38 39 struct Register; 40 41 class SafepointEntry BASE_EMBEDDED { 42 public: SafepointEntry()43 SafepointEntry() : info_(0), bits_(NULL) {} 44 SafepointEntry(unsigned info,uint8_t * bits)45 SafepointEntry(unsigned info, uint8_t* bits) : info_(info), bits_(bits) { 46 ASSERT(is_valid()); 47 } 48 is_valid()49 bool is_valid() const { return bits_ != NULL; } 50 Equals(const SafepointEntry & other)51 bool Equals(const SafepointEntry& other) const { 52 return info_ == other.info_ && bits_ == other.bits_; 53 } 54 Reset()55 void Reset() { 56 info_ = 0; 57 bits_ = NULL; 58 } 59 deoptimization_index()60 int deoptimization_index() const { 61 ASSERT(is_valid()); 62 return DeoptimizationIndexField::decode(info_); 63 } 64 65 static const int kArgumentsFieldBits = 3; 66 static const int kSaveDoublesFieldBits = 1; 67 static const int kDeoptIndexBits = 68 32 - kArgumentsFieldBits - kSaveDoublesFieldBits; 69 class DeoptimizationIndexField: 70 public BitField<int, 0, kDeoptIndexBits> {}; // NOLINT 71 class ArgumentsField: 72 public BitField<unsigned, 73 kDeoptIndexBits, 74 kArgumentsFieldBits> {}; // NOLINT 75 class SaveDoublesField: 76 public BitField<bool, 77 kDeoptIndexBits + kArgumentsFieldBits, 78 kSaveDoublesFieldBits> { }; // NOLINT 79 argument_count()80 int argument_count() const { 81 ASSERT(is_valid()); 82 return ArgumentsField::decode(info_); 83 } 84 has_doubles()85 bool has_doubles() const { 86 ASSERT(is_valid()); 87 return SaveDoublesField::decode(info_); 88 } 89 bits()90 uint8_t* bits() { 91 ASSERT(is_valid()); 92 return bits_; 93 } 94 95 bool HasRegisters() const; 96 bool HasRegisterAt(int reg_index) const; 97 98 private: 99 unsigned info_; 100 uint8_t* bits_; 101 }; 102 103 104 class SafepointTable BASE_EMBEDDED { 105 public: 106 explicit SafepointTable(Code* code); 107 size()108 int size() const { 109 return kHeaderSize + 110 (length_ * (kPcAndDeoptimizationIndexSize + entry_size_)); } length()111 unsigned length() const { return length_; } entry_size()112 unsigned entry_size() const { return entry_size_; } 113 GetPcOffset(unsigned index)114 unsigned GetPcOffset(unsigned index) const { 115 ASSERT(index < length_); 116 return Memory::uint32_at(GetPcOffsetLocation(index)); 117 } 118 GetEntry(unsigned index)119 SafepointEntry GetEntry(unsigned index) const { 120 ASSERT(index < length_); 121 unsigned info = Memory::uint32_at(GetInfoLocation(index)); 122 uint8_t* bits = &Memory::uint8_at(entries_ + (index * entry_size_)); 123 return SafepointEntry(info, bits); 124 } 125 126 // Returns the entry for the given pc. 127 SafepointEntry FindEntry(Address pc) const; 128 129 void PrintEntry(unsigned index) const; 130 131 private: 132 static const uint8_t kNoRegisters = 0xFF; 133 134 static const int kLengthOffset = 0; 135 static const int kEntrySizeOffset = kLengthOffset + kIntSize; 136 static const int kHeaderSize = kEntrySizeOffset + kIntSize; 137 138 static const int kPcSize = kIntSize; 139 static const int kDeoptimizationIndexSize = kIntSize; 140 static const int kPcAndDeoptimizationIndexSize = 141 kPcSize + kDeoptimizationIndexSize; 142 GetPcOffsetLocation(unsigned index)143 Address GetPcOffsetLocation(unsigned index) const { 144 return pc_and_deoptimization_indexes_ + 145 (index * kPcAndDeoptimizationIndexSize); 146 } 147 GetInfoLocation(unsigned index)148 Address GetInfoLocation(unsigned index) const { 149 return GetPcOffsetLocation(index) + kPcSize; 150 } 151 152 static void PrintBits(uint8_t byte, int digits); 153 154 AssertNoAllocation no_allocation_; 155 Code* code_; 156 unsigned length_; 157 unsigned entry_size_; 158 159 Address pc_and_deoptimization_indexes_; 160 Address entries_; 161 162 friend class SafepointTableBuilder; 163 friend class SafepointEntry; 164 165 DISALLOW_COPY_AND_ASSIGN(SafepointTable); 166 }; 167 168 169 class Safepoint BASE_EMBEDDED { 170 public: 171 typedef enum { 172 kSimple = 0, 173 kWithRegisters = 1 << 0, 174 kWithDoubles = 1 << 1, 175 kWithRegistersAndDoubles = kWithRegisters | kWithDoubles 176 } Kind; 177 178 enum DeoptMode { 179 kNoLazyDeopt, 180 kLazyDeopt 181 }; 182 183 static const int kNoDeoptimizationIndex = 184 (1 << (SafepointEntry::kDeoptIndexBits)) - 1; 185 DefinePointerSlot(int index)186 void DefinePointerSlot(int index) { indexes_->Add(index); } 187 void DefinePointerRegister(Register reg); 188 189 private: Safepoint(ZoneList<int> * indexes,ZoneList<int> * registers)190 Safepoint(ZoneList<int>* indexes, ZoneList<int>* registers) : 191 indexes_(indexes), registers_(registers) { } 192 ZoneList<int>* indexes_; 193 ZoneList<int>* registers_; 194 195 friend class SafepointTableBuilder; 196 }; 197 198 199 class SafepointTableBuilder BASE_EMBEDDED { 200 public: SafepointTableBuilder()201 SafepointTableBuilder() 202 : deoptimization_info_(32), 203 deopt_index_list_(32), 204 indexes_(32), 205 registers_(32), 206 emitted_(false), 207 last_lazy_safepoint_(0) { } 208 209 // Get the offset of the emitted safepoint table in the code. 210 unsigned GetCodeOffset() const; 211 212 // Define a new safepoint for the current position in the body. 213 Safepoint DefineSafepoint(Assembler* assembler, 214 Safepoint::Kind kind, 215 int arguments, 216 Safepoint::DeoptMode mode); 217 218 // Record deoptimization index for lazy deoptimization for the last 219 // outstanding safepoints. 220 void RecordLazyDeoptimizationIndex(int index); 221 222 // Emit the safepoint table after the body. The number of bits per 223 // entry must be enough to hold all the pointer indexes. 224 void Emit(Assembler* assembler, int bits_per_entry); 225 226 227 private: 228 struct DeoptimizationInfo { 229 unsigned pc; 230 unsigned arguments; 231 bool has_doubles; 232 }; 233 234 uint32_t EncodeExceptPC(const DeoptimizationInfo& info, unsigned index); 235 236 ZoneList<DeoptimizationInfo> deoptimization_info_; 237 ZoneList<unsigned> deopt_index_list_; 238 ZoneList<ZoneList<int>*> indexes_; 239 ZoneList<ZoneList<int>*> registers_; 240 241 unsigned offset_; 242 bool emitted_; 243 int last_lazy_safepoint_; 244 245 DISALLOW_COPY_AND_ASSIGN(SafepointTableBuilder); 246 }; 247 248 } } // namespace v8::internal 249 250 #endif // V8_SAFEPOINT_TABLE_H_ 251