1 2 // Copyright 2011 the V8 project authors. All rights reserved. 3 // Use of this source code is governed by a BSD-style license that can be 4 // found in the LICENSE file. 5 6 #include "src/v8.h" 7 8 #include "src/codegen.h" 9 #include "src/deoptimizer.h" 10 #include "src/full-codegen.h" 11 #include "src/safepoint-table.h" 12 13 namespace v8 { 14 namespace internal { 15 16 17 int Deoptimizer::patch_size() { 18 const int kCallInstructionSizeInWords = 4; 19 return kCallInstructionSizeInWords * Assembler::kInstrSize; 20 } 21 22 23 void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) { 24 Address code_start_address = code->instruction_start(); 25 // Invalidate the relocation information, as it will become invalid by the 26 // code patching below, and is not needed any more. 27 code->InvalidateRelocation(); 28 29 if (FLAG_zap_code_space) { 30 // Fail hard and early if we enter this code object again. 31 byte* pointer = code->FindCodeAgeSequence(); 32 if (pointer != NULL) { 33 pointer += kNoCodeAgeSequenceLength; 34 } else { 35 pointer = code->instruction_start(); 36 } 37 CodePatcher patcher(pointer, 1); 38 patcher.masm()->break_(0xCC); 39 40 DeoptimizationInputData* data = 41 DeoptimizationInputData::cast(code->deoptimization_data()); 42 int osr_offset = data->OsrPcOffset()->value(); 43 if (osr_offset > 0) { 44 CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1); 45 osr_patcher.masm()->break_(0xCC); 46 } 47 } 48 49 DeoptimizationInputData* deopt_data = 50 DeoptimizationInputData::cast(code->deoptimization_data()); 51 SharedFunctionInfo* shared = 52 SharedFunctionInfo::cast(deopt_data->SharedFunctionInfo()); 53 shared->EvictFromOptimizedCodeMap(code, "deoptimized code"); 54 #ifdef DEBUG 55 Address prev_call_address = NULL; 56 #endif 57 // For each LLazyBailout instruction insert a call to the corresponding 58 // deoptimization entry. 59 for (int i = 0; i < deopt_data->DeoptCount(); i++) { 60 if (deopt_data->Pc(i)->value() == -1) continue; 61 Address call_address = code_start_address + deopt_data->Pc(i)->value(); 62 Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY); 63 int call_size_in_bytes = MacroAssembler::CallSize(deopt_entry, 64 RelocInfo::NONE32); 65 int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize; 66 ASSERT(call_size_in_bytes % Assembler::kInstrSize == 0); 67 ASSERT(call_size_in_bytes <= patch_size()); 68 CodePatcher patcher(call_address, call_size_in_words); 69 patcher.masm()->Call(deopt_entry, RelocInfo::NONE32); 70 ASSERT(prev_call_address == NULL || 71 call_address >= prev_call_address + patch_size()); 72 ASSERT(call_address + patch_size() <= code->instruction_end()); 73 74 #ifdef DEBUG 75 prev_call_address = call_address; 76 #endif 77 } 78 } 79 80 81 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) { 82 // Set the register values. The values are not important as there are no 83 // callee saved registers in JavaScript frames, so all registers are 84 // spilled. Registers fp and sp are set to the correct values though. 85 86 for (int i = 0; i < Register::kNumRegisters; i++) { 87 input_->SetRegister(i, i * 4); 88 } 89 input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp())); 90 input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp())); 91 for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) { 92 input_->SetDoubleRegister(i, 0.0); 93 } 94 95 // Fill the frame content from the actual data on the frame. 96 for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) { 97 input_->SetFrameSlot(i, Memory::uint32_at(tos + i)); 98 } 99 } 100 101 102 void Deoptimizer::SetPlatformCompiledStubRegisters( 103 FrameDescription* output_frame, CodeStubInterfaceDescriptor* descriptor) { 104 ApiFunction function(descriptor->deoptimization_handler_); 105 ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_); 106 intptr_t handler = reinterpret_cast<intptr_t>(xref.address()); 107 int params = descriptor->GetHandlerParameterCount(); 108 output_frame->SetRegister(s0.code(), params); 109 output_frame->SetRegister(s1.code(), (params - 1) * kPointerSize); 110 output_frame->SetRegister(s2.code(), handler); 111 } 112 113 114 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) { 115 for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) { 116 double double_value = input_->GetDoubleRegister(i); 117 output_frame->SetDoubleRegister(i, double_value); 118 } 119 } 120 121 122 bool Deoptimizer::HasAlignmentPadding(JSFunction* function) { 123 // There is no dynamic alignment padding on MIPS in the input frame. 124 return false; 125 } 126 127 128 #define __ masm()-> 129 130 131 // This code tries to be close to ia32 code so that any changes can be 132 // easily ported. 133 void Deoptimizer::EntryGenerator::Generate() { 134 GeneratePrologue(); 135 136 // Unlike on ARM we don't save all the registers, just the useful ones. 137 // For the rest, there are gaps on the stack, so the offsets remain the same. 138 const int kNumberOfRegisters = Register::kNumRegisters; 139 140 RegList restored_regs = kJSCallerSaved | kCalleeSaved; 141 RegList saved_regs = restored_regs | sp.bit() | ra.bit(); 142 143 const int kDoubleRegsSize = 144 kDoubleSize * FPURegister::kMaxNumAllocatableRegisters; 145 146 // Save all FPU registers before messing with them. 147 __ Subu(sp, sp, Operand(kDoubleRegsSize)); 148 for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) { 149 FPURegister fpu_reg = FPURegister::FromAllocationIndex(i); 150 int offset = i * kDoubleSize; 151 __ sdc1(fpu_reg, MemOperand(sp, offset)); 152 } 153 154 // Push saved_regs (needed to populate FrameDescription::registers_). 155 // Leave gaps for other registers. 156 __ Subu(sp, sp, kNumberOfRegisters * kPointerSize); 157 for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) { 158 if ((saved_regs & (1 << i)) != 0) { 159 __ sw(ToRegister(i), MemOperand(sp, kPointerSize * i)); 160 } 161 } 162 163 const int kSavedRegistersAreaSize = 164 (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize; 165 166 // Get the bailout id from the stack. 167 __ lw(a2, MemOperand(sp, kSavedRegistersAreaSize)); 168 169 // Get the address of the location in the code object (a3) (return 170 // address for lazy deoptimization) and compute the fp-to-sp delta in 171 // register t0. 172 __ mov(a3, ra); 173 // Correct one word for bailout id. 174 __ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize))); 175 176 __ Subu(t0, fp, t0); 177 178 // Allocate a new deoptimizer object. 179 // Pass four arguments in a0 to a3 and fifth & sixth arguments on stack. 180 __ PrepareCallCFunction(6, t1); 181 __ lw(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset)); 182 __ li(a1, Operand(type())); // bailout type, 183 // a2: bailout id already loaded. 184 // a3: code address or 0 already loaded. 185 __ sw(t0, CFunctionArgumentOperand(5)); // Fp-to-sp delta. 186 __ li(t1, Operand(ExternalReference::isolate_address(isolate()))); 187 __ sw(t1, CFunctionArgumentOperand(6)); // Isolate. 188 // Call Deoptimizer::New(). 189 { 190 AllowExternalCallThatCantCauseGC scope(masm()); 191 __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6); 192 } 193 194 // Preserve "deoptimizer" object in register v0 and get the input 195 // frame descriptor pointer to a1 (deoptimizer->input_); 196 // Move deopt-obj to a0 for call to Deoptimizer::ComputeOutputFrames() below. 197 __ mov(a0, v0); 198 __ lw(a1, MemOperand(v0, Deoptimizer::input_offset())); 199 200 // Copy core registers into FrameDescription::registers_[kNumRegisters]. 201 ASSERT(Register::kNumRegisters == kNumberOfRegisters); 202 for (int i = 0; i < kNumberOfRegisters; i++) { 203 int offset = (i * kPointerSize) + FrameDescription::registers_offset(); 204 if ((saved_regs & (1 << i)) != 0) { 205 __ lw(a2, MemOperand(sp, i * kPointerSize)); 206 __ sw(a2, MemOperand(a1, offset)); 207 } else if (FLAG_debug_code) { 208 __ li(a2, kDebugZapValue); 209 __ sw(a2, MemOperand(a1, offset)); 210 } 211 } 212 213 int double_regs_offset = FrameDescription::double_registers_offset(); 214 // Copy FPU registers to 215 // double_registers_[DoubleRegister::kNumAllocatableRegisters] 216 for (int i = 0; i < FPURegister::NumAllocatableRegisters(); ++i) { 217 int dst_offset = i * kDoubleSize + double_regs_offset; 218 int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize; 219 __ ldc1(f0, MemOperand(sp, src_offset)); 220 __ sdc1(f0, MemOperand(a1, dst_offset)); 221 } 222 223 // Remove the bailout id and the saved registers from the stack. 224 __ Addu(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize))); 225 226 // Compute a pointer to the unwinding limit in register a2; that is 227 // the first stack slot not part of the input frame. 228 __ lw(a2, MemOperand(a1, FrameDescription::frame_size_offset())); 229 __ Addu(a2, a2, sp); 230 231 // Unwind the stack down to - but not including - the unwinding 232 // limit and copy the contents of the activation frame to the input 233 // frame description. 234 __ Addu(a3, a1, Operand(FrameDescription::frame_content_offset())); 235 Label pop_loop; 236 Label pop_loop_header; 237 __ BranchShort(&pop_loop_header); 238 __ bind(&pop_loop); 239 __ pop(t0); 240 __ sw(t0, MemOperand(a3, 0)); 241 __ addiu(a3, a3, sizeof(uint32_t)); 242 __ bind(&pop_loop_header); 243 __ BranchShort(&pop_loop, ne, a2, Operand(sp)); 244 245 // Compute the output frame in the deoptimizer. 246 __ push(a0); // Preserve deoptimizer object across call. 247 // a0: deoptimizer object; a1: scratch. 248 __ PrepareCallCFunction(1, a1); 249 // Call Deoptimizer::ComputeOutputFrames(). 250 { 251 AllowExternalCallThatCantCauseGC scope(masm()); 252 __ CallCFunction( 253 ExternalReference::compute_output_frames_function(isolate()), 1); 254 } 255 __ pop(a0); // Restore deoptimizer object (class Deoptimizer). 256 257 // Replace the current (input) frame with the output frames. 258 Label outer_push_loop, inner_push_loop, 259 outer_loop_header, inner_loop_header; 260 // Outer loop state: t0 = current "FrameDescription** output_", 261 // a1 = one past the last FrameDescription**. 262 __ lw(a1, MemOperand(a0, Deoptimizer::output_count_offset())); 263 __ lw(t0, MemOperand(a0, Deoptimizer::output_offset())); // t0 is output_. 264 __ sll(a1, a1, kPointerSizeLog2); // Count to offset. 265 __ addu(a1, t0, a1); // a1 = one past the last FrameDescription**. 266 __ jmp(&outer_loop_header); 267 __ bind(&outer_push_loop); 268 // Inner loop state: a2 = current FrameDescription*, a3 = loop index. 269 __ lw(a2, MemOperand(t0, 0)); // output_[ix] 270 __ lw(a3, MemOperand(a2, FrameDescription::frame_size_offset())); 271 __ jmp(&inner_loop_header); 272 __ bind(&inner_push_loop); 273 __ Subu(a3, a3, Operand(sizeof(uint32_t))); 274 __ Addu(t2, a2, Operand(a3)); 275 __ lw(t3, MemOperand(t2, FrameDescription::frame_content_offset())); 276 __ push(t3); 277 __ bind(&inner_loop_header); 278 __ BranchShort(&inner_push_loop, ne, a3, Operand(zero_reg)); 279 280 __ Addu(t0, t0, Operand(kPointerSize)); 281 __ bind(&outer_loop_header); 282 __ BranchShort(&outer_push_loop, lt, t0, Operand(a1)); 283 284 __ lw(a1, MemOperand(a0, Deoptimizer::input_offset())); 285 for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) { 286 const FPURegister fpu_reg = FPURegister::FromAllocationIndex(i); 287 int src_offset = i * kDoubleSize + double_regs_offset; 288 __ ldc1(fpu_reg, MemOperand(a1, src_offset)); 289 } 290 291 // Push state, pc, and continuation from the last output frame. 292 __ lw(t2, MemOperand(a2, FrameDescription::state_offset())); 293 __ push(t2); 294 295 __ lw(t2, MemOperand(a2, FrameDescription::pc_offset())); 296 __ push(t2); 297 __ lw(t2, MemOperand(a2, FrameDescription::continuation_offset())); 298 __ push(t2); 299 300 301 // Technically restoring 'at' should work unless zero_reg is also restored 302 // but it's safer to check for this. 303 ASSERT(!(at.bit() & restored_regs)); 304 // Restore the registers from the last output frame. 305 __ mov(at, a2); 306 for (int i = kNumberOfRegisters - 1; i >= 0; i--) { 307 int offset = (i * kPointerSize) + FrameDescription::registers_offset(); 308 if ((restored_regs & (1 << i)) != 0) { 309 __ lw(ToRegister(i), MemOperand(at, offset)); 310 } 311 } 312 313 __ InitializeRootRegister(); 314 315 __ pop(at); // Get continuation, leave pc on stack. 316 __ pop(ra); 317 __ Jump(at); 318 __ stop("Unreachable."); 319 } 320 321 322 // Maximum size of a table entry generated below. 323 const int Deoptimizer::table_entry_size_ = 7 * Assembler::kInstrSize; 324 325 void Deoptimizer::TableEntryGenerator::GeneratePrologue() { 326 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm()); 327 328 // Create a sequence of deoptimization entries. 329 // Note that registers are still live when jumping to an entry. 330 Label table_start; 331 __ bind(&table_start); 332 for (int i = 0; i < count(); i++) { 333 Label start; 334 __ bind(&start); 335 __ addiu(sp, sp, -1 * kPointerSize); 336 // Jump over the remaining deopt entries (including this one). 337 // This code is always reached by calling Jump, which puts the target (label 338 // start) into t9. 339 const int remaining_entries = (count() - i) * table_entry_size_; 340 __ Addu(t9, t9, remaining_entries); 341 // 'at' was clobbered so we can only load the current entry value here. 342 __ li(at, i); 343 __ jr(t9); // Expose delay slot. 344 __ sw(at, MemOperand(sp, 0 * kPointerSize)); // In the delay slot. 345 346 // Pad the rest of the code. 347 while (table_entry_size_ > (masm()->SizeOfCodeGeneratedSince(&start))) { 348 __ nop(); 349 } 350 351 ASSERT_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start)); 352 } 353 354 ASSERT_EQ(masm()->SizeOfCodeGeneratedSince(&table_start), 355 count() * table_entry_size_); 356 } 357 358 359 void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) { 360 SetFrameSlot(offset, value); 361 } 362 363 364 void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) { 365 SetFrameSlot(offset, value); 366 } 367 368 369 void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) { 370 // No out-of-line constant pool support. 371 UNREACHABLE(); 372 } 373 374 375 #undef __ 376 377 378 } } // namespace v8::internal 379