1// Copyright 2012 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/v8.h"
6
7#if V8_TARGET_ARCH_X64
8
9#include "src/codegen.h"
10#include "src/deoptimizer.h"
11#include "src/full-codegen.h"
12#include "src/safepoint-table.h"
13
14namespace v8 {
15namespace internal {
16
17
18const int Deoptimizer::table_entry_size_ = 10;
19
20
21int Deoptimizer::patch_size() {
22  return Assembler::kCallSequenceLength;
23}
24
25
26void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
27  // Invalidate the relocation information, as it will become invalid by the
28  // code patching below, and is not needed any more.
29  code->InvalidateRelocation();
30
31  if (FLAG_zap_code_space) {
32    // Fail hard and early if we enter this code object again.
33    byte* pointer = code->FindCodeAgeSequence();
34    if (pointer != NULL) {
35      pointer += kNoCodeAgeSequenceLength;
36    } else {
37      pointer = code->instruction_start();
38    }
39    CodePatcher patcher(pointer, 1);
40    patcher.masm()->int3();
41
42    DeoptimizationInputData* data =
43        DeoptimizationInputData::cast(code->deoptimization_data());
44    int osr_offset = data->OsrPcOffset()->value();
45    if (osr_offset > 0) {
46      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
47      osr_patcher.masm()->int3();
48    }
49  }
50
51  // For each LLazyBailout instruction insert a absolute call to the
52  // corresponding deoptimization entry, or a short call to an absolute
53  // jump if space is short. The absolute jumps are put in a table just
54  // before the safepoint table (space was allocated there when the Code
55  // object was created, if necessary).
56
57  Address instruction_start = code->instruction_start();
58#ifdef DEBUG
59  Address prev_call_address = NULL;
60#endif
61  DeoptimizationInputData* deopt_data =
62      DeoptimizationInputData::cast(code->deoptimization_data());
63  deopt_data->SetSharedFunctionInfo(Smi::FromInt(0));
64  // For each LLazyBailout instruction insert a call to the corresponding
65  // deoptimization entry.
66  for (int i = 0; i < deopt_data->DeoptCount(); i++) {
67    if (deopt_data->Pc(i)->value() == -1) continue;
68    // Position where Call will be patched in.
69    Address call_address = instruction_start + deopt_data->Pc(i)->value();
70    // There is room enough to write a long call instruction because we pad
71    // LLazyBailout instructions with nops if necessary.
72    CodePatcher patcher(call_address, Assembler::kCallSequenceLength);
73    patcher.masm()->Call(GetDeoptimizationEntry(isolate, i, LAZY),
74                         Assembler::RelocInfoNone());
75    DCHECK(prev_call_address == NULL ||
76           call_address >= prev_call_address + patch_size());
77    DCHECK(call_address + patch_size() <= code->instruction_end());
78#ifdef DEBUG
79    prev_call_address = call_address;
80#endif
81  }
82}
83
84
85void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
86  // Set the register values. The values are not important as there are no
87  // callee saved registers in JavaScript frames, so all registers are
88  // spilled. Registers rbp and rsp are set to the correct values though.
89  for (int i = 0; i < Register::kNumRegisters; i++) {
90    input_->SetRegister(i, i * 4);
91  }
92  input_->SetRegister(rsp.code(), reinterpret_cast<intptr_t>(frame->sp()));
93  input_->SetRegister(rbp.code(), reinterpret_cast<intptr_t>(frame->fp()));
94  for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
95    input_->SetDoubleRegister(i, 0.0);
96  }
97
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::uintptr_at(tos + i));
101  }
102}
103
104
105void Deoptimizer::SetPlatformCompiledStubRegisters(
106    FrameDescription* output_frame, CodeStubDescriptor* descriptor) {
107  intptr_t handler =
108      reinterpret_cast<intptr_t>(descriptor->deoptimization_handler());
109  int params = descriptor->GetHandlerParameterCount();
110  output_frame->SetRegister(rax.code(), params);
111  output_frame->SetRegister(rbx.code(), handler);
112}
113
114
115void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
116  for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); ++i) {
117    double double_value = input_->GetDoubleRegister(i);
118    output_frame->SetDoubleRegister(i, double_value);
119  }
120}
121
122
123bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
124  // There is no dynamic alignment padding on x64 in the input frame.
125  return false;
126}
127
128
129#define __ masm()->
130
131void Deoptimizer::EntryGenerator::Generate() {
132  GeneratePrologue();
133
134  // Save all general purpose registers before messing with them.
135  const int kNumberOfRegisters = Register::kNumRegisters;
136
137  const int kDoubleRegsSize = kDoubleSize *
138      XMMRegister::NumAllocatableRegisters();
139  __ subp(rsp, Immediate(kDoubleRegsSize));
140
141  for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); ++i) {
142    XMMRegister xmm_reg = XMMRegister::FromAllocationIndex(i);
143    int offset = i * kDoubleSize;
144    __ movsd(Operand(rsp, offset), xmm_reg);
145  }
146
147  // We push all registers onto the stack, even though we do not need
148  // to restore all later.
149  for (int i = 0; i < kNumberOfRegisters; i++) {
150    Register r = Register::from_code(i);
151    __ pushq(r);
152  }
153
154  const int kSavedRegistersAreaSize = kNumberOfRegisters * kRegisterSize +
155                                      kDoubleRegsSize;
156
157  // We use this to keep the value of the fifth argument temporarily.
158  // Unfortunately we can't store it directly in r8 (used for passing
159  // this on linux), since it is another parameter passing register on windows.
160  Register arg5 = r11;
161
162  // Get the bailout id from the stack.
163  __ movp(arg_reg_3, Operand(rsp, kSavedRegistersAreaSize));
164
165  // Get the address of the location in the code object
166  // and compute the fp-to-sp delta in register arg5.
167  __ movp(arg_reg_4, Operand(rsp, kSavedRegistersAreaSize + 1 * kRegisterSize));
168  __ leap(arg5, Operand(rsp, kSavedRegistersAreaSize + 1 * kRegisterSize +
169                            kPCOnStackSize));
170
171  __ subp(arg5, rbp);
172  __ negp(arg5);
173
174  // Allocate a new deoptimizer object.
175  __ PrepareCallCFunction(6);
176  __ movp(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
177  __ movp(arg_reg_1, rax);
178  __ Set(arg_reg_2, type());
179  // Args 3 and 4 are already in the right registers.
180
181  // On windows put the arguments on the stack (PrepareCallCFunction
182  // has created space for this). On linux pass the arguments in r8 and r9.
183#ifdef _WIN64
184  __ movq(Operand(rsp, 4 * kRegisterSize), arg5);
185  __ LoadAddress(arg5, ExternalReference::isolate_address(isolate()));
186  __ movq(Operand(rsp, 5 * kRegisterSize), arg5);
187#else
188  __ movp(r8, arg5);
189  __ LoadAddress(r9, ExternalReference::isolate_address(isolate()));
190#endif
191
192  { AllowExternalCallThatCantCauseGC scope(masm());
193    __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
194  }
195  // Preserve deoptimizer object in register rax and get the input
196  // frame descriptor pointer.
197  __ movp(rbx, Operand(rax, Deoptimizer::input_offset()));
198
199  // Fill in the input registers.
200  for (int i = kNumberOfRegisters -1; i >= 0; i--) {
201    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
202    __ PopQuad(Operand(rbx, offset));
203  }
204
205  // Fill in the double input registers.
206  int double_regs_offset = FrameDescription::double_registers_offset();
207  for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); i++) {
208    int dst_offset = i * kDoubleSize + double_regs_offset;
209    __ popq(Operand(rbx, dst_offset));
210  }
211
212  // Remove the bailout id and return address from the stack.
213  __ addp(rsp, Immediate(1 * kRegisterSize + kPCOnStackSize));
214
215  // Compute a pointer to the unwinding limit in register rcx; that is
216  // the first stack slot not part of the input frame.
217  __ movp(rcx, Operand(rbx, FrameDescription::frame_size_offset()));
218  __ addp(rcx, rsp);
219
220  // Unwind the stack down to - but not including - the unwinding
221  // limit and copy the contents of the activation frame to the input
222  // frame description.
223  __ leap(rdx, Operand(rbx, FrameDescription::frame_content_offset()));
224  Label pop_loop_header;
225  __ jmp(&pop_loop_header);
226  Label pop_loop;
227  __ bind(&pop_loop);
228  __ Pop(Operand(rdx, 0));
229  __ addp(rdx, Immediate(sizeof(intptr_t)));
230  __ bind(&pop_loop_header);
231  __ cmpp(rcx, rsp);
232  __ j(not_equal, &pop_loop);
233
234  // Compute the output frame in the deoptimizer.
235  __ pushq(rax);
236  __ PrepareCallCFunction(2);
237  __ movp(arg_reg_1, rax);
238  __ LoadAddress(arg_reg_2, ExternalReference::isolate_address(isolate()));
239  {
240    AllowExternalCallThatCantCauseGC scope(masm());
241    __ CallCFunction(
242        ExternalReference::compute_output_frames_function(isolate()), 2);
243  }
244  __ popq(rax);
245
246  // Replace the current frame with the output frames.
247  Label outer_push_loop, inner_push_loop,
248      outer_loop_header, inner_loop_header;
249  // Outer loop state: rax = current FrameDescription**, rdx = one past the
250  // last FrameDescription**.
251  __ movl(rdx, Operand(rax, Deoptimizer::output_count_offset()));
252  __ movp(rax, Operand(rax, Deoptimizer::output_offset()));
253  __ leap(rdx, Operand(rax, rdx, times_pointer_size, 0));
254  __ jmp(&outer_loop_header);
255  __ bind(&outer_push_loop);
256  // Inner loop state: rbx = current FrameDescription*, rcx = loop index.
257  __ movp(rbx, Operand(rax, 0));
258  __ movp(rcx, Operand(rbx, FrameDescription::frame_size_offset()));
259  __ jmp(&inner_loop_header);
260  __ bind(&inner_push_loop);
261  __ subp(rcx, Immediate(sizeof(intptr_t)));
262  __ Push(Operand(rbx, rcx, times_1, FrameDescription::frame_content_offset()));
263  __ bind(&inner_loop_header);
264  __ testp(rcx, rcx);
265  __ j(not_zero, &inner_push_loop);
266  __ addp(rax, Immediate(kPointerSize));
267  __ bind(&outer_loop_header);
268  __ cmpp(rax, rdx);
269  __ j(below, &outer_push_loop);
270
271  for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); ++i) {
272    XMMRegister xmm_reg = XMMRegister::FromAllocationIndex(i);
273    int src_offset = i * kDoubleSize + double_regs_offset;
274    __ movsd(xmm_reg, Operand(rbx, src_offset));
275  }
276
277  // Push state, pc, and continuation from the last output frame.
278  __ Push(Operand(rbx, FrameDescription::state_offset()));
279  __ PushQuad(Operand(rbx, FrameDescription::pc_offset()));
280  __ PushQuad(Operand(rbx, FrameDescription::continuation_offset()));
281
282  // Push the registers from the last output frame.
283  for (int i = 0; i < kNumberOfRegisters; i++) {
284    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
285    __ PushQuad(Operand(rbx, offset));
286  }
287
288  // Restore the registers from the stack.
289  for (int i = kNumberOfRegisters - 1; i >= 0 ; i--) {
290    Register r = Register::from_code(i);
291    // Do not restore rsp, simply pop the value into the next register
292    // and overwrite this afterwards.
293    if (r.is(rsp)) {
294      DCHECK(i > 0);
295      r = Register::from_code(i - 1);
296    }
297    __ popq(r);
298  }
299
300  // Set up the roots register.
301  __ InitializeRootRegister();
302  __ InitializeSmiConstantRegister();
303
304  // Return to the continuation point.
305  __ ret(0);
306}
307
308
309void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
310  // Create a sequence of deoptimization entries.
311  Label done;
312  for (int i = 0; i < count(); i++) {
313    int start = masm()->pc_offset();
314    USE(start);
315    __ pushq_imm32(i);
316    __ jmp(&done);
317    DCHECK(masm()->pc_offset() - start == table_entry_size_);
318  }
319  __ bind(&done);
320}
321
322
323void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
324  if (kPCOnStackSize == 2 * kPointerSize) {
325    // Zero out the high-32 bit of PC for x32 port.
326    SetFrameSlot(offset + kPointerSize, 0);
327  }
328  SetFrameSlot(offset, value);
329}
330
331
332void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
333  if (kFPOnStackSize == 2 * kPointerSize) {
334    // Zero out the high-32 bit of FP for x32 port.
335    SetFrameSlot(offset + kPointerSize, 0);
336  }
337  SetFrameSlot(offset, value);
338}
339
340
341void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
342  // No out-of-line constant pool support.
343  UNREACHABLE();
344}
345
346
347#undef __
348
349
350} }  // namespace v8::internal
351
352#endif  // V8_TARGET_ARCH_X64
353