A64: Implement LOsrEntry and LUnknownOSRValue

src/a64/deoptimizer-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 94 matching lines @@
   ReplaceCodeForRelatedFunctions(function, code);
 
   if (FLAG_trace_deopt) {
     PrintF("[forced deoptimization: ");
     function->PrintName();
     PrintF(" / %" V8PRIxPTR "]\n", reinterpret_cast<intptr_t>(function));
   }
 }
 
 
+// The back edge bookkeeping code matches the pattern:
+//
+//  <decrement profiling counter>
+//  .. .. .. ..       b.pl ok
+//  .. .. .. ..       ldr x16, pc+<interrupt stub address>
+//  .. .. .. ..       blr x16
+//  ok-label
+//
+// We patch the code to the following form:
+//
+//  <decrement profiling counter>
+//  .. .. .. ..       mov x0, x0 (NOP)
+//  .. .. .. ..       ldr x16, pc+<on-stack replacement address>
+//  .. .. .. ..       blr x16
 void Deoptimizer::PatchInterruptCodeAt(Code* unoptimized_code,
                                        Address pc_after,
                                        Code* interrupt_code,
                                        Code* replacement_code) {
-  UNIMPLEMENTED();
   ASSERT(!InterruptCodeIsPatched(unoptimized_code,
                                  pc_after,
                                  interrupt_code,
                                  replacement_code));
+
+  // Turn the jump into a nop.
+  Instruction* jump = Instruction::Cast(pc_after)->preceding(3);
+  PatchingAssembler patcher(jump, 1);
+  patcher.nop(Assembler::INTERRUPT_CODE_NOP);
+
+  // Replace the call address.
+  Instruction* load = Instruction::Cast(pc_after)->preceding(2);
+  Address interrupt_address_pointer =
+      reinterpret_cast<Address>(load) + load->ImmPCOffset();
+  Memory::uint64_at(interrupt_address_pointer) =
+      reinterpret_cast<uint64_t>(replacement_code->entry());
+
+  unoptimized_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
+      unoptimized_code, pc_after - 2 * kInstructionSize, replacement_code);
 }
 
 
 void Deoptimizer::RevertInterruptCodeAt(Code* unoptimized_code,
                                         Address pc_after,
                                         Code* interrupt_code,
                                         Code* replacement_code) {
-  UNIMPLEMENTED();
   ASSERT(InterruptCodeIsPatched(unoptimized_code,
                                 pc_after,
                                 interrupt_code,
                                 replacement_code));
+
+  // Turn the nop into a jump.
+  Instruction* jump = Instruction::Cast(pc_after)->preceding(3);
+  PatchingAssembler patcher(jump, 1);
+  patcher.b(6, pl);  // The ok label is 6 instructions later.
+
+  // Replace the call address.
+  Instruction* load = Instruction::Cast(pc_after)->preceding(2);
+  Address interrupt_address_pointer =
+      reinterpret_cast<Address>(load) + load->ImmPCOffset();
+  Memory::uint64_at(interrupt_address_pointer) =
+      reinterpret_cast<uint64_t>(interrupt_code->entry());
+
+  interrupt_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
+      unoptimized_code, pc_after - 2 * kInstructionSize, interrupt_code);
 }
 
 
 #ifdef DEBUG
 bool Deoptimizer::InterruptCodeIsPatched(Code* unoptimized_code,
                                          Address pc_after,
                                          Code* interrupt_code,
                                          Code* replacement_code) {
-  UNIMPLEMENTED();
-  return false;
+  Instruction* jump_or_nop = Instruction::Cast(pc_after)->preceding(3);
+  return jump_or_nop->IsNop(Assembler::INTERRUPT_CODE_NOP);
 }
 #endif
 
 
-void Deoptimizer::DoComputeOsrOutputFrame() {
-  UNIMPLEMENTED();
+static int LookupBailoutId(DeoptimizationInputData* data, BailoutId ast_id) {
+  ByteArray* translations = data->TranslationByteArray();
+  int length = data->DeoptCount();
+  for (int i = 0; i < length; i++) {
+    if (data->AstId(i) == ast_id) {
+      TranslationIterator it(translations,  data->TranslationIndex(i)->value());
+      int value = it.Next();
+      ASSERT(Translation::BEGIN == static_cast<Translation::Opcode>(value));
+      // Read the number of frames.
+      value = it.Next();
+      if (value == 1) return i;
+    }
+  }
+  UNREACHABLE();
+  return -1;
 }
 
 
+void Deoptimizer::DoComputeOsrOutputFrame() {
+  DeoptimizationInputData* data = DeoptimizationInputData::cast(
+      compiled_code_->deoptimization_data());
+  unsigned ast_id = data->OsrAstId()->value();
+
+  int bailout_id = LookupBailoutId(data, BailoutId(ast_id));
+  unsigned translation_index = data->TranslationIndex(bailout_id)->value();
+  ByteArray* translations = data->TranslationByteArray();
+
+  TranslationIterator iterator(translations, translation_index);
+  Translation::Opcode opcode =
+      static_cast<Translation::Opcode>(iterator.Next());
+  ASSERT(Translation::BEGIN == opcode);
+  USE(opcode);
+  int count = iterator.Next();
+  iterator.Skip(1);  // Drop JS frame count.
+  ASSERT(count == 1);
+  USE(count);
+
+  opcode = static_cast<Translation::Opcode>(iterator.Next());
+  USE(opcode);
+  ASSERT(Translation::JS_FRAME == opcode);
+  unsigned node_id = iterator.Next();
+  USE(node_id);
+  ASSERT(node_id == ast_id);
+  int closure_id = iterator.Next();
+  USE(closure_id);
+  ASSERT_EQ(Translation::kSelfLiteralId, closure_id);
+  unsigned height = iterator.Next();
+  unsigned height_in_bytes = height * kPointerSize;
+  USE(height_in_bytes);
+
+  unsigned fixed_size = ComputeFixedSize(function_);
+  unsigned input_frame_size = input_->GetFrameSize();
+  ASSERT(fixed_size + height_in_bytes == input_frame_size);
+
+  unsigned stack_slot_size = compiled_code_->stack_slots() * kPointerSize;
+  unsigned outgoing_height = data->ArgumentsStackHeight(bailout_id)->value();
+  unsigned outgoing_size = outgoing_height * kPointerSize;
+  unsigned output_frame_size = fixed_size + stack_slot_size + outgoing_size;
+  ASSERT(outgoing_size == 0);  // OSR does not happen in the middle of a call.
+
+  if (FLAG_trace_osr) {
+    PrintF("[on-stack replacement: begin 0x%08" V8PRIxPTR " ",
+           reinterpret_cast<intptr_t>(function_));
+    PrintFunctionName();
+    PrintF(" => node=%u, frame=%d->%d]\n",
+           ast_id,
+           input_frame_size,
+           output_frame_size);
+  }
+
+  // There's only one output frame in the OSR case.
+  output_count_ = 1;
+  output_ = new FrameDescription*[1];
+  output_[0] = new(output_frame_size) FrameDescription(
+      output_frame_size, function_);
+  output_[0]->SetFrameType(StackFrame::JAVA_SCRIPT);
+
+  // Clear the incoming parameters in the optimized frame to avoid
+  // confusing the garbage collector.
+  unsigned output_offset = output_frame_size - kPointerSize;
+  int parameter_count = function_->shared()->formal_parameter_count() + 1;
+  for (int i = 0; i < parameter_count; ++i) {
+    output_[0]->SetFrameSlot(output_offset, 0);
+    output_offset -= kPointerSize;
+  }
+
+  // Translate the incoming parameters. This may overwrite some of the
+  // incoming argument slots we've just cleared.
+  int input_offset = input_frame_size - kPointerSize;
+  bool ok = true;
+  int limit = input_offset - (parameter_count * kPointerSize);
+  while (ok && input_offset > limit) {
+    ok = DoOsrTranslateCommand(&iterator, &input_offset);
+  }
+
+  // There are no translation commands for the caller's pc and fp, the
+  // context, and the function.  Set them up explicitly.
+  for (int i =  StandardFrameConstants::kCallerPCOffset;
+       ok && i >=  StandardFrameConstants::kMarkerOffset;
+       i -= kPointerSize) {
+    uint32_t input_value = input_->GetFrameSlot(input_offset);
+    if (FLAG_trace_osr) {
+      const char* name = "UNKNOWN";
+      switch (i) {
+        case StandardFrameConstants::kCallerPCOffset:
+          name = "caller's pc";
+          break;
+        case StandardFrameConstants::kCallerFPOffset:
+          name = "fp";
+          break;
+        case StandardFrameConstants::kContextOffset:
+          name = "context";
+          break;
+        case StandardFrameConstants::kMarkerOffset:
+          name = "function";
+          break;
+      }
+      PrintF("    [sp + %d] <- 0x%08x ; [sp + %d] (fixed part - %s)\n",
+             output_offset,
+             input_value,
+             input_offset,
+             name);
+    }
+
+    output_[0]->SetFrameSlot(output_offset, input_->GetFrameSlot(input_offset));
+    input_offset -= kPointerSize;
+    output_offset -= kPointerSize;
+  }
+
+  // Translate the rest of the frame.
+  while (ok && input_offset >= 0) {
+    ok = DoOsrTranslateCommand(&iterator, &input_offset);
+  }
+
+  // If translation of any command failed, continue using the input frame.
+  if (!ok) {
+    delete output_[0];
+    output_[0] = input_;
+    output_[0]->SetPc(reinterpret_cast<uint64_t>(from_));
+  } else {
+    // Set up the frame pointer and the context pointer.
+    output_[0]->SetRegister(fp.code(), input_->GetRegister(fp.code()));
+    output_[0]->SetRegister(cp.code(), input_->GetRegister(cp.code()));
+
+    unsigned pc_offset = data->OsrPcOffset()->value();
+    uint64_t pc = reinterpret_cast<uint64_t>(
+        compiled_code_->entry() + pc_offset);
+    output_[0]->SetPc(pc);
+  }
+  Code* continuation = isolate_->builtins()->builtin(Builtins::kNotifyOSR);
+  output_[0]->SetContinuation(
+      reinterpret_cast<uint64_t>(continuation->entry()));
+
+  if (FLAG_trace_osr) {
+    PrintF("[on-stack replacement translation %s: 0x%08" V8PRIxPTR " ",
+           ok ? "finished" : "aborted",
+           reinterpret_cast<intptr_t>(function_));
+    PrintFunctionName();
+    PrintF(" => pc=0x%0lx]\n", output_[0]->GetPc());
+  }
+}
+
+
 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
   // Set the register values. The values are not important as there are no
   // callee saved registers in JavaScript frames, so all registers are
   // spilled. Registers fp and sp are set to the correct values though.
   for (int i = 0; i < Register::NumRegisters(); i++) {
     input_->SetRegister(i, 0);
   }
 
   // TODO(all): Do we also need to set a value to csp?
   input_->SetRegister(jssp.code(), reinterpret_cast<intptr_t>(frame->sp()));
@@ skipping 72 matching lines @@
   // and compute the fp-to-sp delta.
   Register code_object = x3;
   Register fp_to_sp = x4;
   if ((type() == EAGER) || (type() == SOFT)) {
     __ Mov(code_object, 0);
     // Correct one word for bailout id.
     __ Add(fp_to_sp,
            masm()->StackPointer(),
            kSavedRegistersAreaSize + (1 * kPointerSize));
   } else if (type() == OSR) {
-    UNIMPLEMENTED();
+    __ Mov(code_object, lr);
+    // Correct one word for bailout id.
+    __ Add(fp_to_sp,
+           masm()->StackPointer(),
+           kSavedRegistersAreaSize + (1 * kPointerSize));
   } else {
     __ Mov(code_object, lr);
     // Correct two words for bailout id and return address.
     __ Add(fp_to_sp,
            masm()->StackPointer(),
            kSavedRegistersAreaSize + (2 * kPointerSize));
   }
   __ Sub(fp_to_sp, fp, fp_to_sp);
 
   // Allocate a new deoptimizer object.
@@ skipping 186 matching lines @@
   }
   __ Bind(&done);
   // TODO(all): We need to add some kind of assertion to verify that Tmp0()
   // is not clobbered by Push.
   __ Push(masm()->Tmp0());
 }
 
 #undef __
 
 } }  // namespace v8::internal