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::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) {
24 // Empty because there is no need for relocation information for the code
25 // patching in Deoptimizer::PatchCodeForDeoptimization below.
29 void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
30 Address code_start_address = code->instruction_start();
31 // Invalidate the relocation information, as it will become invalid by the
32 // code patching below, and is not needed any more.
33 code->InvalidateRelocation();
35 if (FLAG_zap_code_space) {
36 // Fail hard and early if we enter this code object again.
37 byte* pointer = code->FindCodeAgeSequence();
38 if (pointer != NULL) {
39 pointer += kNoCodeAgeSequenceLength;
41 pointer = code->instruction_start();
43 CodePatcher patcher(pointer, 1);
44 patcher.masm()->break_(0xCC);
46 DeoptimizationInputData* data =
47 DeoptimizationInputData::cast(code->deoptimization_data());
48 int osr_offset = data->OsrPcOffset()->value();
50 CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
51 osr_patcher.masm()->break_(0xCC);
55 DeoptimizationInputData* deopt_data =
56 DeoptimizationInputData::cast(code->deoptimization_data());
58 Address prev_call_address = NULL;
60 // For each LLazyBailout instruction insert a call to the corresponding
61 // deoptimization entry.
62 for (int i = 0; i < deopt_data->DeoptCount(); i++) {
63 if (deopt_data->Pc(i)->value() == -1) continue;
64 Address call_address = code_start_address + deopt_data->Pc(i)->value();
65 Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
66 int call_size_in_bytes = MacroAssembler::CallSize(deopt_entry,
68 int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize;
69 DCHECK(call_size_in_bytes % Assembler::kInstrSize == 0);
70 DCHECK(call_size_in_bytes <= patch_size());
71 CodePatcher patcher(call_address, call_size_in_words);
72 patcher.masm()->Call(deopt_entry, RelocInfo::NONE32);
73 DCHECK(prev_call_address == NULL ||
74 call_address >= prev_call_address + patch_size());
75 DCHECK(call_address + patch_size() <= code->instruction_end());
78 prev_call_address = call_address;
84 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
85 // Set the register values. The values are not important as there are no
86 // callee saved registers in JavaScript frames, so all registers are
87 // spilled. Registers fp and sp are set to the correct values though.
89 for (int i = 0; i < Register::kNumRegisters; i++) {
90 input_->SetRegister(i, i * 4);
92 input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp()));
93 input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp()));
94 for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
95 input_->SetDoubleRegister(i, 0.0);
98 // Fill the frame content from the actual data on the frame.
99 for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
100 input_->SetFrameSlot(i, Memory::uint32_at(tos + i));
105 void Deoptimizer::SetPlatformCompiledStubRegisters(
106 FrameDescription* output_frame, CodeStubDescriptor* descriptor) {
107 ApiFunction function(descriptor->deoptimization_handler());
108 ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_);
109 intptr_t handler = reinterpret_cast<intptr_t>(xref.address());
110 int params = descriptor->GetHandlerParameterCount();
111 output_frame->SetRegister(a0.code(), params);
112 output_frame->SetRegister(a1.code(), handler);
116 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
117 for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
118 double double_value = input_->GetDoubleRegister(i);
119 output_frame->SetDoubleRegister(i, double_value);
124 bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
125 // There is no dynamic alignment padding on MIPS in the input frame.
133 // This code tries to be close to ia32 code so that any changes can be
135 void Deoptimizer::EntryGenerator::Generate() {
138 // Unlike on ARM we don't save all the registers, just the useful ones.
139 // For the rest, there are gaps on the stack, so the offsets remain the same.
140 const int kNumberOfRegisters = Register::kNumRegisters;
142 RegList restored_regs = kJSCallerSaved | kCalleeSaved;
143 RegList saved_regs = restored_regs | sp.bit() | ra.bit();
145 const int kDoubleRegsSize =
146 kDoubleSize * FPURegister::kMaxNumAllocatableRegisters;
148 // Save all FPU registers before messing with them.
149 __ Subu(sp, sp, Operand(kDoubleRegsSize));
150 for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) {
151 FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
152 int offset = i * kDoubleSize;
153 __ sdc1(fpu_reg, MemOperand(sp, offset));
156 // Push saved_regs (needed to populate FrameDescription::registers_).
157 // Leave gaps for other registers.
158 __ Subu(sp, sp, kNumberOfRegisters * kPointerSize);
159 for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
160 if ((saved_regs & (1 << i)) != 0) {
161 __ sw(ToRegister(i), MemOperand(sp, kPointerSize * i));
165 __ li(a2, Operand(ExternalReference(Isolate::kCEntryFPAddress, isolate())));
166 __ sw(fp, MemOperand(a2));
168 const int kSavedRegistersAreaSize =
169 (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
171 // Get the bailout id from the stack.
172 __ lw(a2, MemOperand(sp, kSavedRegistersAreaSize));
174 // Get the address of the location in the code object (a3) (return
175 // address for lazy deoptimization) and compute the fp-to-sp delta in
178 // Correct one word for bailout id.
179 __ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
183 // Allocate a new deoptimizer object.
184 // Pass four arguments in a0 to a3 and fifth & sixth arguments on stack.
185 __ PrepareCallCFunction(6, t1);
186 __ lw(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
187 __ li(a1, Operand(type())); // bailout type,
188 // a2: bailout id already loaded.
189 // a3: code address or 0 already loaded.
190 __ sw(t0, CFunctionArgumentOperand(5)); // Fp-to-sp delta.
191 __ li(t1, Operand(ExternalReference::isolate_address(isolate())));
192 __ sw(t1, CFunctionArgumentOperand(6)); // Isolate.
193 // Call Deoptimizer::New().
195 AllowExternalCallThatCantCauseGC scope(masm());
196 __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
199 // Preserve "deoptimizer" object in register v0 and get the input
200 // frame descriptor pointer to a1 (deoptimizer->input_);
201 // Move deopt-obj to a0 for call to Deoptimizer::ComputeOutputFrames() below.
203 __ lw(a1, MemOperand(v0, Deoptimizer::input_offset()));
205 // Copy core registers into FrameDescription::registers_[kNumRegisters].
206 DCHECK(Register::kNumRegisters == kNumberOfRegisters);
207 for (int i = 0; i < kNumberOfRegisters; i++) {
208 int offset = (i * kPointerSize) + FrameDescription::registers_offset();
209 if ((saved_regs & (1 << i)) != 0) {
210 __ lw(a2, MemOperand(sp, i * kPointerSize));
211 __ sw(a2, MemOperand(a1, offset));
212 } else if (FLAG_debug_code) {
213 __ li(a2, kDebugZapValue);
214 __ sw(a2, MemOperand(a1, offset));
218 int double_regs_offset = FrameDescription::double_registers_offset();
219 // Copy FPU registers to
220 // double_registers_[DoubleRegister::kNumAllocatableRegisters]
221 for (int i = 0; i < FPURegister::NumAllocatableRegisters(); ++i) {
222 int dst_offset = i * kDoubleSize + double_regs_offset;
223 int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
224 __ ldc1(f0, MemOperand(sp, src_offset));
225 __ sdc1(f0, MemOperand(a1, dst_offset));
228 // Remove the bailout id and the saved registers from the stack.
229 __ Addu(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
231 // Compute a pointer to the unwinding limit in register a2; that is
232 // the first stack slot not part of the input frame.
233 __ lw(a2, MemOperand(a1, FrameDescription::frame_size_offset()));
236 // Unwind the stack down to - but not including - the unwinding
237 // limit and copy the contents of the activation frame to the input
238 // frame description.
239 __ Addu(a3, a1, Operand(FrameDescription::frame_content_offset()));
241 Label pop_loop_header;
242 __ BranchShort(&pop_loop_header);
245 __ sw(t0, MemOperand(a3, 0));
246 __ addiu(a3, a3, sizeof(uint32_t));
247 __ bind(&pop_loop_header);
248 __ BranchShort(&pop_loop, ne, a2, Operand(sp));
250 // Compute the output frame in the deoptimizer.
251 __ push(a0); // Preserve deoptimizer object across call.
252 // a0: deoptimizer object; a1: scratch.
253 __ PrepareCallCFunction(1, a1);
254 // Call Deoptimizer::ComputeOutputFrames().
256 AllowExternalCallThatCantCauseGC scope(masm());
258 ExternalReference::compute_output_frames_function(isolate()), 1);
260 __ pop(a0); // Restore deoptimizer object (class Deoptimizer).
262 // Replace the current (input) frame with the output frames.
263 Label outer_push_loop, inner_push_loop,
264 outer_loop_header, inner_loop_header;
265 // Outer loop state: t0 = current "FrameDescription** output_",
266 // a1 = one past the last FrameDescription**.
267 __ lw(a1, MemOperand(a0, Deoptimizer::output_count_offset()));
268 __ lw(t0, MemOperand(a0, Deoptimizer::output_offset())); // t0 is output_.
269 __ sll(a1, a1, kPointerSizeLog2); // Count to offset.
270 __ addu(a1, t0, a1); // a1 = one past the last FrameDescription**.
271 __ jmp(&outer_loop_header);
272 __ bind(&outer_push_loop);
273 // Inner loop state: a2 = current FrameDescription*, a3 = loop index.
274 __ lw(a2, MemOperand(t0, 0)); // output_[ix]
275 __ lw(a3, MemOperand(a2, FrameDescription::frame_size_offset()));
276 __ jmp(&inner_loop_header);
277 __ bind(&inner_push_loop);
278 __ Subu(a3, a3, Operand(sizeof(uint32_t)));
279 __ Addu(t2, a2, Operand(a3));
280 __ lw(t3, MemOperand(t2, FrameDescription::frame_content_offset()));
282 __ bind(&inner_loop_header);
283 __ BranchShort(&inner_push_loop, ne, a3, Operand(zero_reg));
285 __ Addu(t0, t0, Operand(kPointerSize));
286 __ bind(&outer_loop_header);
287 __ BranchShort(&outer_push_loop, lt, t0, Operand(a1));
289 __ lw(a1, MemOperand(a0, Deoptimizer::input_offset()));
290 for (int i = 0; i < FPURegister::kMaxNumAllocatableRegisters; ++i) {
291 const FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
292 int src_offset = i * kDoubleSize + double_regs_offset;
293 __ ldc1(fpu_reg, MemOperand(a1, src_offset));
296 // Push state, pc, and continuation from the last output frame.
297 __ lw(t2, MemOperand(a2, FrameDescription::state_offset()));
300 __ lw(t2, MemOperand(a2, FrameDescription::pc_offset()));
302 __ lw(t2, MemOperand(a2, FrameDescription::continuation_offset()));
306 // Technically restoring 'at' should work unless zero_reg is also restored
307 // but it's safer to check for this.
308 DCHECK(!(at.bit() & restored_regs));
309 // Restore the registers from the last output frame.
311 for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
312 int offset = (i * kPointerSize) + FrameDescription::registers_offset();
313 if ((restored_regs & (1 << i)) != 0) {
314 __ lw(ToRegister(i), MemOperand(at, offset));
318 __ InitializeRootRegister();
320 __ pop(at); // Get continuation, leave pc on stack.
323 __ stop("Unreachable.");
327 // Maximum size of a table entry generated below.
328 const int Deoptimizer::table_entry_size_ = 2 * Assembler::kInstrSize;
330 void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
331 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
333 // Create a sequence of deoptimization entries.
334 // Note that registers are still live when jumping to an entry.
335 Label table_start, done, done_special, trampoline_jump;
336 __ bind(&table_start);
337 int kMaxEntriesBranchReach = (1 << (kImm16Bits - 2))/
338 (table_entry_size_ / Assembler::kInstrSize);
340 if (count() <= kMaxEntriesBranchReach) {
342 for (int i = 0; i < count(); i++) {
346 __ Branch(USE_DELAY_SLOT, &done); // Expose delay slot.
347 __ li(at, i); // In the delay slot.
349 DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
352 DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
353 count() * table_entry_size_);
357 // Uncommon case, the branch cannot reach.
358 // Create mini trampoline and adjust id constants to get proper value at
360 for (int i = kMaxEntriesBranchReach; i > 1; i--) {
364 __ Branch(USE_DELAY_SLOT, &trampoline_jump); // Expose delay slot.
365 __ li(at, - i); // In the delay slot.
366 DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
368 // Entry with id == kMaxEntriesBranchReach - 1.
369 __ bind(&trampoline_jump);
370 __ Branch(USE_DELAY_SLOT, &done_special);
373 for (int i = kMaxEntriesBranchReach ; i < count(); i++) {
377 __ Branch(USE_DELAY_SLOT, &done); // Expose delay slot.
378 __ li(at, i); // In the delay slot.
381 DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
382 count() * table_entry_size_);
383 __ bind(&done_special);
384 __ addiu(at, at, kMaxEntriesBranchReach);
391 void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
392 SetFrameSlot(offset, value);
396 void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
397 SetFrameSlot(offset, value);
401 void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
402 // No out-of-line constant pool support.
410 } } // namespace v8::internal