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::SetPlatformCompiledStubRegisters( 92 FrameDescription* output_frame, CodeStubDescriptor* descriptor) { 93 ApiFunction function(descriptor->deoptimization_handler()); 94 ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_); 95 intptr_t handler = reinterpret_cast<intptr_t>(xref.address()); 96 int params = descriptor->GetHandlerParameterCount(); 97 output_frame->SetRegister(r3.code(), params); 98 output_frame->SetRegister(r4.code(), handler); 99 } 100 101 102 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) { 103 for (int i = 0; i < DoubleRegister::kNumRegisters; ++i) { 104 Float64 double_value = input_->GetDoubleRegister(i); 105 output_frame->SetDoubleRegister(i, double_value); 106 } 107 } 108 109 #define __ masm()-> 110 111 // This code tries to be close to ia32 code so that any changes can be 112 // easily ported. 113 void Deoptimizer::TableEntryGenerator::Generate() { 114 GeneratePrologue(); 115 116 // Unlike on ARM we don't save all the registers, just the useful ones. 117 // For the rest, there are gaps on the stack, so the offsets remain the same. 118 const int kNumberOfRegisters = Register::kNumRegisters; 119 120 RegList restored_regs = kJSCallerSaved | kCalleeSaved; 121 RegList saved_regs = restored_regs | sp.bit(); 122 123 const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters; 124 125 // Save all double registers before messing with them. 126 __ subi(sp, sp, Operand(kDoubleRegsSize)); 127 const RegisterConfiguration* config = RegisterConfiguration::Crankshaft(); 128 for (int i = 0; i < config->num_allocatable_double_registers(); ++i) { 129 int code = config->GetAllocatableDoubleCode(i); 130 const DoubleRegister dreg = DoubleRegister::from_code(code); 131 int offset = code * kDoubleSize; 132 __ stfd(dreg, MemOperand(sp, offset)); 133 } 134 135 // Push saved_regs (needed to populate FrameDescription::registers_). 136 // Leave gaps for other registers. 137 __ subi(sp, sp, Operand(kNumberOfRegisters * kPointerSize)); 138 for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) { 139 if ((saved_regs & (1 << i)) != 0) { 140 __ StoreP(ToRegister(i), MemOperand(sp, kPointerSize * i)); 141 } 142 } 143 144 __ mov(ip, Operand(ExternalReference(Isolate::kCEntryFPAddress, isolate()))); 145 __ StoreP(fp, MemOperand(ip)); 146 147 const int kSavedRegistersAreaSize = 148 (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize; 149 150 // Get the bailout id from the stack. 151 __ LoadP(r5, MemOperand(sp, kSavedRegistersAreaSize)); 152 153 // Get the address of the location in the code object (r6) (return 154 // address for lazy deoptimization) and compute the fp-to-sp delta in 155 // register r7. 156 __ mflr(r6); 157 // Correct one word for bailout id. 158 __ addi(r7, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize))); 159 __ sub(r7, fp, r7); 160 161 // Allocate a new deoptimizer object. 162 // Pass six arguments in r3 to r8. 163 __ PrepareCallCFunction(6, r8); 164 __ li(r3, Operand::Zero()); 165 Label context_check; 166 __ LoadP(r4, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset)); 167 __ JumpIfSmi(r4, &context_check); 168 __ LoadP(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset)); 169 __ bind(&context_check); 170 __ li(r4, Operand(type())); // bailout type, 171 // r5: bailout id already loaded. 172 // r6: code address or 0 already loaded. 173 // r7: Fp-to-sp delta. 174 __ mov(r8, Operand(ExternalReference::isolate_address(isolate()))); 175 // Call Deoptimizer::New(). 176 { 177 AllowExternalCallThatCantCauseGC scope(masm()); 178 __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6); 179 } 180 181 // Preserve "deoptimizer" object in register r3 and get the input 182 // frame descriptor pointer to r4 (deoptimizer->input_); 183 __ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset())); 184 185 // Copy core registers into FrameDescription::registers_[kNumRegisters]. 186 DCHECK(Register::kNumRegisters == kNumberOfRegisters); 187 for (int i = 0; i < kNumberOfRegisters; i++) { 188 int offset = (i * kPointerSize) + FrameDescription::registers_offset(); 189 __ LoadP(r5, MemOperand(sp, i * kPointerSize)); 190 __ StoreP(r5, MemOperand(r4, offset)); 191 } 192 193 int double_regs_offset = FrameDescription::double_registers_offset(); 194 // Copy double registers to 195 // double_registers_[DoubleRegister::kNumRegisters] 196 for (int i = 0; i < config->num_allocatable_double_registers(); ++i) { 197 int code = config->GetAllocatableDoubleCode(i); 198 int dst_offset = code * kDoubleSize + double_regs_offset; 199 int src_offset = code * kDoubleSize + kNumberOfRegisters * kPointerSize; 200 __ lfd(d0, MemOperand(sp, src_offset)); 201 __ stfd(d0, MemOperand(r4, dst_offset)); 202 } 203 204 // Remove the bailout id and the saved registers from the stack. 205 __ addi(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize))); 206 207 // Compute a pointer to the unwinding limit in register r5; that is 208 // the first stack slot not part of the input frame. 209 __ LoadP(r5, MemOperand(r4, FrameDescription::frame_size_offset())); 210 __ add(r5, r5, sp); 211 212 // Unwind the stack down to - but not including - the unwinding 213 // limit and copy the contents of the activation frame to the input 214 // frame description. 215 __ addi(r6, r4, Operand(FrameDescription::frame_content_offset())); 216 Label pop_loop; 217 Label pop_loop_header; 218 __ b(&pop_loop_header); 219 __ bind(&pop_loop); 220 __ pop(r7); 221 __ StoreP(r7, MemOperand(r6, 0)); 222 __ addi(r6, r6, Operand(kPointerSize)); 223 __ bind(&pop_loop_header); 224 __ cmp(r5, sp); 225 __ bne(&pop_loop); 226 227 // Compute the output frame in the deoptimizer. 228 __ push(r3); // Preserve deoptimizer object across call. 229 // r3: deoptimizer object; r4: scratch. 230 __ PrepareCallCFunction(1, r4); 231 // Call Deoptimizer::ComputeOutputFrames(). 232 { 233 AllowExternalCallThatCantCauseGC scope(masm()); 234 __ CallCFunction( 235 ExternalReference::compute_output_frames_function(isolate()), 1); 236 } 237 __ pop(r3); // Restore deoptimizer object (class Deoptimizer). 238 239 __ LoadP(sp, MemOperand(r3, Deoptimizer::caller_frame_top_offset())); 240 241 // Replace the current (input) frame with the output frames. 242 Label outer_push_loop, inner_push_loop, outer_loop_header, inner_loop_header; 243 // Outer loop state: r7 = current "FrameDescription** output_", 244 // r4 = one past the last FrameDescription**. 245 __ lwz(r4, MemOperand(r3, Deoptimizer::output_count_offset())); 246 __ LoadP(r7, MemOperand(r3, Deoptimizer::output_offset())); // r7 is output_. 247 __ ShiftLeftImm(r4, r4, Operand(kPointerSizeLog2)); 248 __ add(r4, r7, r4); 249 __ b(&outer_loop_header); 250 251 __ bind(&outer_push_loop); 252 // Inner loop state: r5 = current FrameDescription*, r6 = loop index. 253 __ LoadP(r5, MemOperand(r7, 0)); // output_[ix] 254 __ LoadP(r6, MemOperand(r5, FrameDescription::frame_size_offset())); 255 __ b(&inner_loop_header); 256 257 __ bind(&inner_push_loop); 258 __ addi(r6, r6, Operand(-sizeof(intptr_t))); 259 __ add(r9, r5, r6); 260 __ LoadP(r9, MemOperand(r9, FrameDescription::frame_content_offset())); 261 __ push(r9); 262 263 __ bind(&inner_loop_header); 264 __ cmpi(r6, Operand::Zero()); 265 __ bne(&inner_push_loop); // test for gt? 266 267 __ addi(r7, r7, Operand(kPointerSize)); 268 __ bind(&outer_loop_header); 269 __ cmp(r7, r4); 270 __ blt(&outer_push_loop); 271 272 __ LoadP(r4, MemOperand(r3, Deoptimizer::input_offset())); 273 for (int i = 0; i < config->num_allocatable_double_registers(); ++i) { 274 int code = config->GetAllocatableDoubleCode(i); 275 const DoubleRegister dreg = DoubleRegister::from_code(code); 276 int src_offset = code * kDoubleSize + double_regs_offset; 277 __ lfd(dreg, MemOperand(r4, src_offset)); 278 } 279 280 // Push state, pc, and continuation from the last output frame. 281 __ LoadP(r9, MemOperand(r5, FrameDescription::state_offset())); 282 __ push(r9); 283 __ LoadP(r9, MemOperand(r5, FrameDescription::pc_offset())); 284 __ push(r9); 285 __ LoadP(r9, MemOperand(r5, FrameDescription::continuation_offset())); 286 __ push(r9); 287 288 // Restore the registers from the last output frame. 289 DCHECK(!(ip.bit() & restored_regs)); 290 __ mr(ip, r5); 291 for (int i = kNumberOfRegisters - 1; i >= 0; i--) { 292 int offset = (i * kPointerSize) + FrameDescription::registers_offset(); 293 if ((restored_regs & (1 << i)) != 0) { 294 __ LoadP(ToRegister(i), MemOperand(ip, offset)); 295 } 296 } 297 298 __ InitializeRootRegister(); 299 300 __ pop(ip); // get continuation, leave pc on stack 301 __ pop(r0); 302 __ mtlr(r0); 303 __ Jump(ip); 304 __ stop("Unreachable."); 305 } 306 307 308 void Deoptimizer::TableEntryGenerator::GeneratePrologue() { 309 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm()); 310 311 // Create a sequence of deoptimization entries. 312 // Note that registers are still live when jumping to an entry. 313 Label done; 314 for (int i = 0; i < count(); i++) { 315 int start = masm()->pc_offset(); 316 USE(start); 317 __ li(ip, Operand(i)); 318 __ b(&done); 319 DCHECK(masm()->pc_offset() - start == table_entry_size_); 320 } 321 __ bind(&done); 322 __ push(ip); 323 } 324 325 326 void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) { 327 SetFrameSlot(offset, value); 328 } 329 330 331 void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) { 332 SetFrameSlot(offset, value); 333 } 334 335 336 void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) { 337 DCHECK(FLAG_enable_embedded_constant_pool); 338 SetFrameSlot(offset, value); 339 } 340 341 342 #undef __ 343 } // namespace internal 344 } // namespace v8 345