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 #include "v8.h" 29 30 #include "safepoint-table.h" 31 32 #include "deoptimizer.h" 33 #include "disasm.h" 34 #include "macro-assembler.h" 35 #include "zone-inl.h" 36 37 namespace v8 { 38 namespace internal { 39 40 41 bool SafepointEntry::HasRegisters() const { 42 ASSERT(is_valid()); 43 ASSERT(IsAligned(kNumSafepointRegisters, kBitsPerByte)); 44 const int num_reg_bytes = kNumSafepointRegisters >> kBitsPerByteLog2; 45 for (int i = 0; i < num_reg_bytes; i++) { 46 if (bits_[i] != SafepointTable::kNoRegisters) return true; 47 } 48 return false; 49 } 50 51 52 bool SafepointEntry::HasRegisterAt(int reg_index) const { 53 ASSERT(is_valid()); 54 ASSERT(reg_index >= 0 && reg_index < kNumSafepointRegisters); 55 int byte_index = reg_index >> kBitsPerByteLog2; 56 int bit_index = reg_index & (kBitsPerByte - 1); 57 return (bits_[byte_index] & (1 << bit_index)) != 0; 58 } 59 60 61 SafepointTable::SafepointTable(Code* code) { 62 ASSERT(code->is_crankshafted()); 63 code_ = code; 64 Address header = code->instruction_start() + code->safepoint_table_offset(); 65 length_ = Memory::uint32_at(header + kLengthOffset); 66 entry_size_ = Memory::uint32_at(header + kEntrySizeOffset); 67 pc_and_deoptimization_indexes_ = header + kHeaderSize; 68 entries_ = pc_and_deoptimization_indexes_ + 69 (length_ * kPcAndDeoptimizationIndexSize); 70 ASSERT(entry_size_ > 0); 71 STATIC_ASSERT(SafepointEntry::DeoptimizationIndexField::kMax == 72 Safepoint::kNoDeoptimizationIndex); 73 } 74 75 76 SafepointEntry SafepointTable::FindEntry(Address pc) const { 77 unsigned pc_offset = static_cast<unsigned>(pc - code_->instruction_start()); 78 for (unsigned i = 0; i < length(); i++) { 79 // TODO(kasperl): Replace the linear search with binary search. 80 if (GetPcOffset(i) == pc_offset) return GetEntry(i); 81 } 82 return SafepointEntry(); 83 } 84 85 86 void SafepointTable::PrintEntry(unsigned index, FILE* out) const { 87 disasm::NameConverter converter; 88 SafepointEntry entry = GetEntry(index); 89 uint8_t* bits = entry.bits(); 90 91 // Print the stack slot bits. 92 if (entry_size_ > 0) { 93 ASSERT(IsAligned(kNumSafepointRegisters, kBitsPerByte)); 94 const int first = kNumSafepointRegisters >> kBitsPerByteLog2; 95 int last = entry_size_ - 1; 96 for (int i = first; i < last; i++) PrintBits(out, bits[i], kBitsPerByte); 97 int last_bits = code_->stack_slots() - ((last - first) * kBitsPerByte); 98 PrintBits(out, bits[last], last_bits); 99 100 // Print the registers (if any). 101 if (!entry.HasRegisters()) return; 102 for (int j = 0; j < kNumSafepointRegisters; j++) { 103 if (entry.HasRegisterAt(j)) { 104 PrintF(out, " | %s", converter.NameOfCPURegister(j)); 105 } 106 } 107 } 108 } 109 110 111 void SafepointTable::PrintBits(FILE* out, uint8_t byte, int digits) { 112 ASSERT(digits >= 0 && digits <= kBitsPerByte); 113 for (int i = 0; i < digits; i++) { 114 PrintF(out, "%c", ((byte & (1 << i)) == 0) ? '0' : '1'); 115 } 116 } 117 118 119 void Safepoint::DefinePointerRegister(Register reg, Zone* zone) { 120 registers_->Add(reg.code(), zone); 121 } 122 123 124 Safepoint SafepointTableBuilder::DefineSafepoint( 125 Assembler* assembler, 126 Safepoint::Kind kind, 127 int arguments, 128 Safepoint::DeoptMode deopt_mode) { 129 ASSERT(arguments >= 0); 130 DeoptimizationInfo info; 131 info.pc = assembler->pc_offset(); 132 info.arguments = arguments; 133 info.has_doubles = (kind & Safepoint::kWithDoubles); 134 deoptimization_info_.Add(info, zone_); 135 deopt_index_list_.Add(Safepoint::kNoDeoptimizationIndex, zone_); 136 if (deopt_mode == Safepoint::kNoLazyDeopt) { 137 last_lazy_safepoint_ = deopt_index_list_.length(); 138 } 139 indexes_.Add(new(zone_) ZoneList<int>(8, zone_), zone_); 140 registers_.Add((kind & Safepoint::kWithRegisters) 141 ? new(zone_) ZoneList<int>(4, zone_) 142 : NULL, 143 zone_); 144 return Safepoint(indexes_.last(), registers_.last()); 145 } 146 147 148 void SafepointTableBuilder::RecordLazyDeoptimizationIndex(int index) { 149 while (last_lazy_safepoint_ < deopt_index_list_.length()) { 150 deopt_index_list_[last_lazy_safepoint_++] = index; 151 } 152 } 153 154 unsigned SafepointTableBuilder::GetCodeOffset() const { 155 ASSERT(emitted_); 156 return offset_; 157 } 158 159 160 void SafepointTableBuilder::Emit(Assembler* assembler, int bits_per_entry) { 161 // Make sure the safepoint table is properly aligned. Pad with nops. 162 assembler->Align(kIntSize); 163 assembler->RecordComment(";;; Safepoint table."); 164 offset_ = assembler->pc_offset(); 165 166 // Take the register bits into account. 167 bits_per_entry += kNumSafepointRegisters; 168 169 // Compute the number of bytes per safepoint entry. 170 int bytes_per_entry = 171 RoundUp(bits_per_entry, kBitsPerByte) >> kBitsPerByteLog2; 172 173 // Emit the table header. 174 int length = deoptimization_info_.length(); 175 assembler->dd(length); 176 assembler->dd(bytes_per_entry); 177 178 // Emit sorted table of pc offsets together with deoptimization indexes. 179 for (int i = 0; i < length; i++) { 180 assembler->dd(deoptimization_info_[i].pc); 181 assembler->dd(EncodeExceptPC(deoptimization_info_[i], 182 deopt_index_list_[i])); 183 } 184 185 // Emit table of bitmaps. 186 ZoneList<uint8_t> bits(bytes_per_entry, zone_); 187 for (int i = 0; i < length; i++) { 188 ZoneList<int>* indexes = indexes_[i]; 189 ZoneList<int>* registers = registers_[i]; 190 bits.Clear(); 191 bits.AddBlock(0, bytes_per_entry, zone_); 192 193 // Run through the registers (if any). 194 ASSERT(IsAligned(kNumSafepointRegisters, kBitsPerByte)); 195 if (registers == NULL) { 196 const int num_reg_bytes = kNumSafepointRegisters >> kBitsPerByteLog2; 197 for (int j = 0; j < num_reg_bytes; j++) { 198 bits[j] = SafepointTable::kNoRegisters; 199 } 200 } else { 201 for (int j = 0; j < registers->length(); j++) { 202 int index = registers->at(j); 203 ASSERT(index >= 0 && index < kNumSafepointRegisters); 204 int byte_index = index >> kBitsPerByteLog2; 205 int bit_index = index & (kBitsPerByte - 1); 206 bits[byte_index] |= (1 << bit_index); 207 } 208 } 209 210 // Run through the indexes and build a bitmap. 211 for (int j = 0; j < indexes->length(); j++) { 212 int index = bits_per_entry - 1 - indexes->at(j); 213 int byte_index = index >> kBitsPerByteLog2; 214 int bit_index = index & (kBitsPerByte - 1); 215 bits[byte_index] |= (1U << bit_index); 216 } 217 218 // Emit the bitmap for the current entry. 219 for (int k = 0; k < bytes_per_entry; k++) { 220 assembler->db(bits[k]); 221 } 222 } 223 emitted_ = true; 224 } 225 226 227 uint32_t SafepointTableBuilder::EncodeExceptPC(const DeoptimizationInfo& info, 228 unsigned index) { 229 uint32_t encoding = SafepointEntry::DeoptimizationIndexField::encode(index); 230 encoding |= SafepointEntry::ArgumentsField::encode(info.arguments); 231 encoding |= SafepointEntry::SaveDoublesField::encode(info.has_doubles); 232 return encoding; 233 } 234 235 236 237 } } // namespace v8::internal 238