1 // Copyright 2014 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "src/codegen.h" 6 #include "src/deoptimizer.h" 7 #include "src/full-codegen/full-codegen.h" 8 #include "src/register-configuration.h" 9 #include "src/safepoint-table.h" 10 11 namespace v8 { 12 namespace internal { 13 14 const int Deoptimizer::table_entry_size_ = 8; 15 16 17 int Deoptimizer::patch_size() { 18 #if V8_TARGET_ARCH_PPC64 19 const int kCallInstructionSizeInWords = 7; 20 #else 21 const int kCallInstructionSizeInWords = 4; 22 #endif 23 return kCallInstructionSizeInWords * Assembler::kInstrSize; 24 } 25 26 27 void Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) { 28 // Empty because there is no need for relocation information for the code 29 // patching in Deoptimizer::PatchCodeForDeoptimization below. 30 } 31 32 33 void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) { 34 Address code_start_address = code->instruction_start(); 35 36 // Invalidate the relocation information, as it will become invalid by the 37 // code patching below, and is not needed any more. 38 code->InvalidateRelocation(); 39 40 if (FLAG_zap_code_space) { 41 // Fail hard and early if we enter this code object again. 42 byte* pointer = code->FindCodeAgeSequence(); 43 if (pointer != NULL) { 44 pointer += kNoCodeAgeSequenceLength; 45 } else { 46 pointer = code->instruction_start(); 47 } 48 CodePatcher patcher(isolate, pointer, 1); 49 patcher.masm()->bkpt(0); 50 51 DeoptimizationInputData* data = 52 DeoptimizationInputData::cast(code->deoptimization_data()); 53 int osr_offset = data->OsrPcOffset()->value(); 54 if (osr_offset > 0) { 55 CodePatcher osr_patcher(isolate, code->instruction_start() + osr_offset, 56 1); 57 osr_patcher.masm()->bkpt(0); 58 } 59 } 60 61 DeoptimizationInputData* deopt_data = 62 DeoptimizationInputData::cast(code->deoptimization_data()); 63 #ifdef DEBUG 64 Address prev_call_address = NULL; 65 #endif 66 // For each LLazyBailout instruction insert a call to the corresponding 67 // deoptimization entry. 68 for (int i = 0; i < deopt_data->DeoptCount(); i++) { 69 if (deopt_data->Pc(i)->value() == -1) continue; 70 Address call_address = code_start_address + deopt_data->Pc(i)->value(); 71 Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY); 72 // We need calls to have a predictable size in the unoptimized code, but 73 // this is optimized code, so we don't have to have a predictable size. 74 int call_size_in_bytes = MacroAssembler::CallSizeNotPredictableCodeSize( 75 deopt_entry, kRelocInfo_NONEPTR); 76 int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize; 77 DCHECK(call_size_in_bytes % Assembler::kInstrSize == 0); 78 DCHECK(call_size_in_bytes <= patch_size()); 79 CodePatcher patcher(isolate, call_address, call_size_in_words); 80 patcher.masm()->Call(deopt_entry, kRelocInfo_NONEPTR); 81 DCHECK(prev_call_address == NULL || 82 call_address >= prev_call_address + patch_size()); 83 DCHECK(call_address + patch_size() <= code->instruction_end()); 84 #ifdef DEBUG 85 prev_call_address = call_address; 86 #endif 87 } 88 } 89 90 91 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) { 92 // Set the register values. The values are not important as there are no 93 // callee saved registers in JavaScript frames, so all registers are 94 // spilled. Registers fp and sp are set to the correct values though. 95 // We ensure the values are Smis to avoid confusing the garbage 96 // collector in the event that any values are retreived and stored 97 // elsewhere. 98 99 for (int i = 0; i < Register::kNumRegisters; i++) { 100 input_->SetRegister(i, reinterpret_cast<intptr_t>(Smi::FromInt(i))); 101 } 102 input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp())); 103 input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp())); 104 for (int i = 0; i < DoubleRegister::kNumRegisters; i++) { 105 input_->SetDoubleRegister(i, 0.0); 106 } 107 108 // Fill the frame content from the actual data on the frame. 109 for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) { 110 input_->SetFrameSlot( 111 i, reinterpret_cast<intptr_t>(Memory::Address_at(tos + i))); 112 } 113 } 114 115 116 void Deoptimizer::SetPlatformCompiledStubRegisters( 117 FrameDescription* output_frame, CodeStubDescriptor* descriptor) { 118 ApiFunction function(descriptor->deoptimization_handler()); 119 ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_); 120 intptr_t handler = reinterpret_cast<intptr_t>(xref.address()); 121 int params = descriptor->GetHandlerParameterCount(); 122 output_frame->SetRegister(r3.code(), params); 123 output_frame->SetRegister(r4.code(), handler); 124 } 125 126 127 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) { 128 for (int i = 0; i < DoubleRegister::kNumRegisters; ++i) { 129 double double_value = input_->GetDoubleRegister(i); 130 output_frame->SetDoubleRegister(i, double_value); 131 } 132 } 133 134 135 bool Deoptimizer::HasAlignmentPadding(JSFunction* function) { 136 // There is no dynamic alignment padding on PPC in the input frame. 137 return false; 138 } 139 140 141 #define __ masm()-> 142 143 // This code tries to be close to ia32 code so that any changes can be 144 // easily ported. 145 void Deoptimizer::TableEntryGenerator::Generate() { 146 GeneratePrologue(); 147 148 // Unlike on ARM we don't save all the registers, just the useful ones. 149 // For the rest, there are gaps on the stack, so the offsets remain the same. 150 const int kNumberOfRegisters = Register::kNumRegisters; 151 152 RegList restored_regs = kJSCallerSaved | kCalleeSaved; 153 RegList saved_regs = restored_regs | sp.bit(); 154 155 const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters; 156 157 // Save all double registers before messing with them. 158 __ subi(sp, sp, Operand(kDoubleRegsSize)); 159 const RegisterConfiguration* config = 160 RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT); 161 for (int i = 0; i < config->num_allocatable_double_registers(); ++i) { 162 int code = config->GetAllocatableDoubleCode(i); 163 const DoubleRegister dreg = DoubleRegister::from_code(code); 164 int offset = code * kDoubleSize; 165 __ stfd(dreg, MemOperand(sp, offset)); 166 } 167 168 // Push saved_regs (needed to populate FrameDescription::registers_). 169 // Leave gaps for other registers. 170 __ subi(sp, sp, Operand(kNumberOfRegisters * kPointerSize)); 171 for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) { 172 if ((saved_regs & (1 << i)) != 0) { 173 __ StoreP(ToRegister(i), MemOperand(sp, kPointerSize * i)); 174 } 175 } 176 177 __ mov(ip, Operand(ExternalReference(Isolate::kCEntryFPAddress, isolate()))); 178 __ StoreP(fp, MemOperand(ip)); 179 180 const int kSavedRegistersAreaSize = 181 (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize; 182 183 // Get the bailout id from the stack. 184 __ LoadP(r5, MemOperand(sp, kSavedRegistersAreaSize)); 185 186 // Get the address of the location in the code object (r6) (return 187 // address for lazy deoptimization) and compute the fp-to-sp delta in 188 // register r7. 189 __ mflr(r6); 190 // Correct one word for bailout id. 191 __ addi(r7, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize))); 192 __ sub(r7, fp, r7); 193 194 // Allocate a new deoptimizer object. 195 // Pass six arguments in r3 to r8. 196 __ PrepareCallCFunction(6, r8); 197 __ LoadP(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset)); 198 __ li(r4, Operand(type())); // bailout type, 199 // r5: bailout id already loaded. 200 // r6: code address or 0 already loaded. 201 // r7: Fp-to-sp delta. 202 __ mov(r8, Operand(ExternalReference::isolate_address(isolate()))); 203 // Call Deoptimizer::New(). 204 { 205 AllowExternalCallThatCantCauseGC scope(masm()); 206 __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6); 207 } 208 209 // Preserve "deoptimizer" object in register r3 and get the input 210 // frame descriptor pointer to r4 (deoptimizer->input_); 211 __ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset())); 212 213 // Copy core registers into FrameDescription::registers_[kNumRegisters]. 214 DCHECK(Register::kNumRegisters == kNumberOfRegisters); 215 for (int i = 0; i < kNumberOfRegisters; i++) { 216 int offset = (i * kPointerSize) + FrameDescription::registers_offset(); 217 __ LoadP(r5, MemOperand(sp, i * kPointerSize)); 218 __ StoreP(r5, MemOperand(r4, offset)); 219 } 220 221 int double_regs_offset = FrameDescription::double_registers_offset(); 222 // Copy double registers to 223 // double_registers_[DoubleRegister::kNumRegisters] 224 for (int i = 0; i < config->num_allocatable_double_registers(); ++i) { 225 int code = config->GetAllocatableDoubleCode(i); 226 int dst_offset = code * kDoubleSize + double_regs_offset; 227 int src_offset = code * kDoubleSize + kNumberOfRegisters * kPointerSize; 228 __ lfd(d0, MemOperand(sp, src_offset)); 229 __ stfd(d0, MemOperand(r4, dst_offset)); 230 } 231 232 // Remove the bailout id and the saved registers from the stack. 233 __ addi(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize))); 234 235 // Compute a pointer to the unwinding limit in register r5; that is 236 // the first stack slot not part of the input frame. 237 __ LoadP(r5, MemOperand(r4, FrameDescription::frame_size_offset())); 238 __ add(r5, r5, sp); 239 240 // Unwind the stack down to - but not including - the unwinding 241 // limit and copy the contents of the activation frame to the input 242 // frame description. 243 __ addi(r6, r4, Operand(FrameDescription::frame_content_offset())); 244 Label pop_loop; 245 Label pop_loop_header; 246 __ b(&pop_loop_header); 247 __ bind(&pop_loop); 248 __ pop(r7); 249 __ StoreP(r7, MemOperand(r6, 0)); 250 __ addi(r6, r6, Operand(kPointerSize)); 251 __ bind(&pop_loop_header); 252 __ cmp(r5, sp); 253 __ bne(&pop_loop); 254 255 // Compute the output frame in the deoptimizer. 256 __ push(r3); // Preserve deoptimizer object across call. 257 // r3: deoptimizer object; r4: scratch. 258 __ PrepareCallCFunction(1, r4); 259 // Call Deoptimizer::ComputeOutputFrames(). 260 { 261 AllowExternalCallThatCantCauseGC scope(masm()); 262 __ CallCFunction( 263 ExternalReference::compute_output_frames_function(isolate()), 1); 264 } 265 __ pop(r3); // Restore deoptimizer object (class Deoptimizer). 266 267 // Replace the current (input) frame with the output frames. 268 Label outer_push_loop, inner_push_loop, outer_loop_header, inner_loop_header; 269 // Outer loop state: r7 = current "FrameDescription** output_", 270 // r4 = one past the last FrameDescription**. 271 __ lwz(r4, MemOperand(r3, Deoptimizer::output_count_offset())); 272 __ LoadP(r7, MemOperand(r3, Deoptimizer::output_offset())); // r7 is output_. 273 __ ShiftLeftImm(r4, r4, Operand(kPointerSizeLog2)); 274 __ add(r4, r7, r4); 275 __ b(&outer_loop_header); 276 277 __ bind(&outer_push_loop); 278 // Inner loop state: r5 = current FrameDescription*, r6 = loop index. 279 __ LoadP(r5, MemOperand(r7, 0)); // output_[ix] 280 __ LoadP(r6, MemOperand(r5, FrameDescription::frame_size_offset())); 281 __ b(&inner_loop_header); 282 283 __ bind(&inner_push_loop); 284 __ addi(r6, r6, Operand(-sizeof(intptr_t))); 285 __ add(r9, r5, r6); 286 __ LoadP(r9, MemOperand(r9, FrameDescription::frame_content_offset())); 287 __ push(r9); 288 289 __ bind(&inner_loop_header); 290 __ cmpi(r6, Operand::Zero()); 291 __ bne(&inner_push_loop); // test for gt? 292 293 __ addi(r7, r7, Operand(kPointerSize)); 294 __ bind(&outer_loop_header); 295 __ cmp(r7, r4); 296 __ blt(&outer_push_loop); 297 298 __ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset())); 299 for (int i = 0; i < config->num_allocatable_double_registers(); ++i) { 300 int code = config->GetAllocatableDoubleCode(i); 301 const DoubleRegister dreg = DoubleRegister::from_code(code); 302 int src_offset = code * kDoubleSize + double_regs_offset; 303 __ lfd(dreg, MemOperand(r4, src_offset)); 304 } 305 306 // Push state, pc, and continuation from the last output frame. 307 __ LoadP(r9, MemOperand(r5, FrameDescription::state_offset())); 308 __ push(r9); 309 __ LoadP(r9, MemOperand(r5, FrameDescription::pc_offset())); 310 __ push(r9); 311 __ LoadP(r9, MemOperand(r5, FrameDescription::continuation_offset())); 312 __ push(r9); 313 314 // Restore the registers from the last output frame. 315 DCHECK(!(ip.bit() & restored_regs)); 316 __ mr(ip, r5); 317 for (int i = kNumberOfRegisters - 1; i >= 0; i--) { 318 int offset = (i * kPointerSize) + FrameDescription::registers_offset(); 319 if ((restored_regs & (1 << i)) != 0) { 320 __ LoadP(ToRegister(i), MemOperand(ip, offset)); 321 } 322 } 323 324 __ InitializeRootRegister(); 325 326 __ pop(ip); // get continuation, leave pc on stack 327 __ pop(r0); 328 __ mtlr(r0); 329 __ Jump(ip); 330 __ stop("Unreachable."); 331 } 332 333 334 void Deoptimizer::TableEntryGenerator::GeneratePrologue() { 335 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm()); 336 337 // Create a sequence of deoptimization entries. 338 // Note that registers are still live when jumping to an entry. 339 Label done; 340 for (int i = 0; i < count(); i++) { 341 int start = masm()->pc_offset(); 342 USE(start); 343 __ li(ip, Operand(i)); 344 __ b(&done); 345 DCHECK(masm()->pc_offset() - start == table_entry_size_); 346 } 347 __ bind(&done); 348 __ push(ip); 349 } 350 351 352 void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) { 353 SetFrameSlot(offset, value); 354 } 355 356 357 void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) { 358 SetFrameSlot(offset, value); 359 } 360 361 362 void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) { 363 DCHECK(FLAG_enable_embedded_constant_pool); 364 SetFrameSlot(offset, value); 365 } 366 367 368 #undef __ 369 } // namespace internal 370 } // namespace v8 371