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.
8 #include "src/codegen.h"
9 #include "src/deoptimizer.h"
10 #include "src/full-codegen.h"
11 #include "src/safepoint-table.h"
17 int Deoptimizer::patch_size() {
18 const int kCallInstructionSizeInWords = 4;
19 return kCallInstructionSizeInWords * Assembler::kInstrSize;
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();
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;
35 pointer = code->instruction_start();
37 CodePatcher patcher(pointer, 1);
38 patcher.masm()->break_(0xCC);
40 DeoptimizationInputData* data =
41 DeoptimizationInputData::cast(code->deoptimization_data());
42 int osr_offset = data->OsrPcOffset()->value();
44 CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
45 osr_patcher.masm()->break_(0xCC);
49 DeoptimizationInputData* deopt_data =
50 DeoptimizationInputData::cast(code->deoptimization_data());
52 Address prev_call_address = NULL;
54 // For each LLazyBailout instruction insert a call to the corresponding
55 // deoptimization entry.
56 for (int i = 0; i < deopt_data->DeoptCount(); i++) {
57 if (deopt_data->Pc(i)->value() == -1) continue;
58 Address call_address = code_start_address + deopt_data->Pc(i)->value();
59 Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
60 int call_size_in_bytes = MacroAssembler::CallSize(deopt_entry,
62 int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize;
63 DCHECK(call_size_in_bytes % Assembler::kInstrSize == 0);
64 DCHECK(call_size_in_bytes <= patch_size());
65 CodePatcher patcher(call_address, call_size_in_words);
66 patcher.masm()->Call(deopt_entry, RelocInfo::NONE32);
67 DCHECK(prev_call_address == NULL ||
68 call_address >= prev_call_address + patch_size());
69 DCHECK(call_address + patch_size() <= code->instruction_end());
72 prev_call_address = call_address;
78 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
79 // Set the register values. The values are not important as there are no
80 // callee saved registers in JavaScript frames, so all registers are
81 // spilled. Registers fp and sp are set to the correct values though.
83 for (int i = 0; i < Register::kNumRegisters; i++) {
84 input_->SetRegister(i, i * 4);
86 input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp()));
87 input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp()));
88 for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
89 input_->SetDoubleRegister(i, 0.0);
92 // Fill the frame content from the actual data on the frame.
93 for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
94 input_->SetFrameSlot(i, Memory::uint32_at(tos + i));
99 void Deoptimizer::SetPlatformCompiledStubRegisters(
100 FrameDescription* output_frame, CodeStubInterfaceDescriptor* descriptor) {
101 ApiFunction function(descriptor->deoptimization_handler());
102 ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_);
103 intptr_t handler = reinterpret_cast<intptr_t>(xref.address());
104 int params = descriptor->GetHandlerParameterCount();
105 output_frame->SetRegister(s0.code(), params);
106 output_frame->SetRegister(s1.code(), (params - 1) * kPointerSize);
107 output_frame->SetRegister(s2.code(), handler);
111 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
112 for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
113 double double_value = input_->GetDoubleRegister(i);
114 output_frame->SetDoubleRegister(i, double_value);
119 bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
120 // There is no dynamic alignment padding on MIPS in the input frame.
128 // This code tries to be close to ia32 code so that any changes can be
130 void Deoptimizer::EntryGenerator::Generate() {
133 // Unlike on ARM we don't save all the registers, just the useful ones.
134 // For the rest, there are gaps on the stack, so the offsets remain the same.
135 const int kNumberOfRegisters = Register::kNumRegisters;
137 RegList restored_regs = kJSCallerSaved | kCalleeSaved;
138 RegList saved_regs = restored_regs | sp.bit() | ra.bit();
140 const int kDoubleRegsSize =
141 kDoubleSize * FPURegister::kMaxNumAllocatableRegisters;
143 // Save all FPU registers before messing with them.
144 __ Subu(sp, sp, Operand(kDoubleRegsSize));
145 for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) {
146 FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
147 int offset = i * kDoubleSize;
148 __ sdc1(fpu_reg, MemOperand(sp, offset));
151 // Push saved_regs (needed to populate FrameDescription::registers_).
152 // Leave gaps for other registers.
153 __ Subu(sp, sp, kNumberOfRegisters * kPointerSize);
154 for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
155 if ((saved_regs & (1 << i)) != 0) {
156 __ sw(ToRegister(i), MemOperand(sp, kPointerSize * i));
160 const int kSavedRegistersAreaSize =
161 (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
163 // Get the bailout id from the stack.
164 __ lw(a2, MemOperand(sp, kSavedRegistersAreaSize));
166 // Get the address of the location in the code object (a3) (return
167 // address for lazy deoptimization) and compute the fp-to-sp delta in
170 // Correct one word for bailout id.
171 __ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
175 // Allocate a new deoptimizer object.
176 // Pass four arguments in a0 to a3 and fifth & sixth arguments on stack.
177 __ PrepareCallCFunction(6, t1);
178 __ lw(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
179 __ li(a1, Operand(type())); // bailout type,
180 // a2: bailout id already loaded.
181 // a3: code address or 0 already loaded.
182 __ sw(t0, CFunctionArgumentOperand(5)); // Fp-to-sp delta.
183 __ li(t1, Operand(ExternalReference::isolate_address(isolate())));
184 __ sw(t1, CFunctionArgumentOperand(6)); // Isolate.
185 // Call Deoptimizer::New().
187 AllowExternalCallThatCantCauseGC scope(masm());
188 __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
191 // Preserve "deoptimizer" object in register v0 and get the input
192 // frame descriptor pointer to a1 (deoptimizer->input_);
193 // Move deopt-obj to a0 for call to Deoptimizer::ComputeOutputFrames() below.
195 __ lw(a1, MemOperand(v0, Deoptimizer::input_offset()));
197 // Copy core registers into FrameDescription::registers_[kNumRegisters].
198 DCHECK(Register::kNumRegisters == kNumberOfRegisters);
199 for (int i = 0; i < kNumberOfRegisters; i++) {
200 int offset = (i * kPointerSize) + FrameDescription::registers_offset();
201 if ((saved_regs & (1 << i)) != 0) {
202 __ lw(a2, MemOperand(sp, i * kPointerSize));
203 __ sw(a2, MemOperand(a1, offset));
204 } else if (FLAG_debug_code) {
205 __ li(a2, kDebugZapValue);
206 __ sw(a2, MemOperand(a1, offset));
210 int double_regs_offset = FrameDescription::double_registers_offset();
211 // Copy FPU registers to
212 // double_registers_[DoubleRegister::kNumAllocatableRegisters]
213 for (int i = 0; i < FPURegister::NumAllocatableRegisters(); ++i) {
214 int dst_offset = i * kDoubleSize + double_regs_offset;
215 int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
216 __ ldc1(f0, MemOperand(sp, src_offset));
217 __ sdc1(f0, MemOperand(a1, dst_offset));
220 // Remove the bailout id and the saved registers from the stack.
221 __ Addu(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
223 // Compute a pointer to the unwinding limit in register a2; that is
224 // the first stack slot not part of the input frame.
225 __ lw(a2, MemOperand(a1, FrameDescription::frame_size_offset()));
228 // Unwind the stack down to - but not including - the unwinding
229 // limit and copy the contents of the activation frame to the input
230 // frame description.
231 __ Addu(a3, a1, Operand(FrameDescription::frame_content_offset()));
233 Label pop_loop_header;
234 __ BranchShort(&pop_loop_header);
237 __ sw(t0, MemOperand(a3, 0));
238 __ addiu(a3, a3, sizeof(uint32_t));
239 __ bind(&pop_loop_header);
240 __ BranchShort(&pop_loop, ne, a2, Operand(sp));
242 // Compute the output frame in the deoptimizer.
243 __ push(a0); // Preserve deoptimizer object across call.
244 // a0: deoptimizer object; a1: scratch.
245 __ PrepareCallCFunction(1, a1);
246 // Call Deoptimizer::ComputeOutputFrames().
248 AllowExternalCallThatCantCauseGC scope(masm());
250 ExternalReference::compute_output_frames_function(isolate()), 1);
252 __ pop(a0); // Restore deoptimizer object (class Deoptimizer).
254 // Replace the current (input) frame with the output frames.
255 Label outer_push_loop, inner_push_loop,
256 outer_loop_header, inner_loop_header;
257 // Outer loop state: t0 = current "FrameDescription** output_",
258 // a1 = one past the last FrameDescription**.
259 __ lw(a1, MemOperand(a0, Deoptimizer::output_count_offset()));
260 __ lw(t0, MemOperand(a0, Deoptimizer::output_offset())); // t0 is output_.
261 __ sll(a1, a1, kPointerSizeLog2); // Count to offset.
262 __ addu(a1, t0, a1); // a1 = one past the last FrameDescription**.
263 __ jmp(&outer_loop_header);
264 __ bind(&outer_push_loop);
265 // Inner loop state: a2 = current FrameDescription*, a3 = loop index.
266 __ lw(a2, MemOperand(t0, 0)); // output_[ix]
267 __ lw(a3, MemOperand(a2, FrameDescription::frame_size_offset()));
268 __ jmp(&inner_loop_header);
269 __ bind(&inner_push_loop);
270 __ Subu(a3, a3, Operand(sizeof(uint32_t)));
271 __ Addu(t2, a2, Operand(a3));
272 __ lw(t3, MemOperand(t2, FrameDescription::frame_content_offset()));
274 __ bind(&inner_loop_header);
275 __ BranchShort(&inner_push_loop, ne, a3, Operand(zero_reg));
277 __ Addu(t0, t0, Operand(kPointerSize));
278 __ bind(&outer_loop_header);
279 __ BranchShort(&outer_push_loop, lt, t0, Operand(a1));
281 __ lw(a1, MemOperand(a0, Deoptimizer::input_offset()));
282 for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) {
283 const FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
284 int src_offset = i * kDoubleSize + double_regs_offset;
285 __ ldc1(fpu_reg, MemOperand(a1, src_offset));
288 // Push state, pc, and continuation from the last output frame.
289 __ lw(t2, MemOperand(a2, FrameDescription::state_offset()));
292 __ lw(t2, MemOperand(a2, FrameDescription::pc_offset()));
294 __ lw(t2, MemOperand(a2, FrameDescription::continuation_offset()));
298 // Technically restoring 'at' should work unless zero_reg is also restored
299 // but it's safer to check for this.
300 DCHECK(!(at.bit() & restored_regs));
301 // Restore the registers from the last output frame.
303 for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
304 int offset = (i * kPointerSize) + FrameDescription::registers_offset();
305 if ((restored_regs & (1 << i)) != 0) {
306 __ lw(ToRegister(i), MemOperand(at, offset));
310 __ InitializeRootRegister();
312 __ pop(at); // Get continuation, leave pc on stack.
315 __ stop("Unreachable.");
319 // Maximum size of a table entry generated below.
320 const int Deoptimizer::table_entry_size_ = 2 * Assembler::kInstrSize;
322 void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
323 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
325 // Create a sequence of deoptimization entries.
326 // Note that registers are still live when jumping to an entry.
327 Label table_start, done;
328 __ bind(&table_start);
329 for (int i = 0; i < count(); i++) {
333 __ Branch(USE_DELAY_SLOT, &done); // Expose delay slot.
334 __ li(at, i); // In the delay slot.
336 DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
339 DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
340 count() * table_entry_size_);
346 void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
347 SetFrameSlot(offset, value);
351 void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
352 SetFrameSlot(offset, value);
356 void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
357 // No out-of-line constant pool support.
365 } } // namespace v8::internal