MIPS: crankshaft implementation

src/mips/deoptimizer-mips.cc

 // Copyright 2011 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 14 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "v8.h"
 
 #include "codegen.h"
 #include "deoptimizer.h"
 #include "full-codegen.h"
 #include "safepoint-table.h"
 
-// Note: this file was taken from the X64 version. ARM has a partially working
-// lithium implementation, but for now it is not ported to mips.
-
 namespace v8 {
 namespace internal {
 
 
-const int Deoptimizer::table_entry_size_ = 10;
+const int Deoptimizer::table_entry_size_ = 32;
 
 
 int Deoptimizer::patch_size() {
-  const int kCallInstructionSizeInWords = 3;
+  const int kCallInstructionSizeInWords = 4;
   return kCallInstructionSizeInWords * Assembler::kInstrSize;
 }
 
 
-void Deoptimizer::DeoptimizeFunction(JSFunction* function) {
-  UNIMPLEMENTED();
+void Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) {
+  // Nothing to do. No new relocation information is written for lazy
+  // deoptimization on MIPS.
 }
 
 
+void Deoptimizer::DeoptimizeFunction(JSFunction* function) {
+  HandleScope scope;
+  AssertNoAllocation no_allocation;
+
+  if (!function->IsOptimized()) return;
+
+  // Get the optimized code.
+  Code* code = function->code();
+
+  // Invalidate the relocation information, as it will become invalid by the
+  // code patching below, and is not needed any more.
+  code->InvalidateRelocation();
+
+  // For each return after a safepoint insert an absolute call to the
+  // corresponding deoptimization entry.
+  unsigned last_pc_offset = 0;
+  SafepointTable table(function->code());
+  for (unsigned i = 0; i < table.length(); i++) {
+    unsigned pc_offset = table.GetPcOffset(i);
+    SafepointEntry safepoint_entry = table.GetEntry(i);
+    int deoptimization_index = safepoint_entry.deoptimization_index();
+    int gap_code_size = safepoint_entry.gap_code_size();
+    // Check that we did not shoot past next safepoint.
+    CHECK(pc_offset >= last_pc_offset);
+#ifdef DEBUG
+    // Destroy the code which is not supposed to be run again.
+    int instructions = (pc_offset - last_pc_offset) / Assembler::kInstrSize;
+    CodePatcher destroyer(code->instruction_start() + last_pc_offset,
+                          instructions);
+    for (int x = 0; x < instructions; x++) {
+      destroyer.masm()->break_(0);
+    }
+#endif
+    last_pc_offset = pc_offset;
+    if (deoptimization_index != Safepoint::kNoDeoptimizationIndex) {
+      Address deoptimization_entry = Deoptimizer::GetDeoptimizationEntry(
+          deoptimization_index, Deoptimizer::LAZY);
+      last_pc_offset += gap_code_size;
+      int call_size_in_bytes = MacroAssembler::CallSize(deoptimization_entry,
+                                                        RelocInfo::NONE);
+      int call_size_in_words = call_size_in_bytes / Assembler::kInstrSize;
+      ASSERT(call_size_in_bytes % Assembler::kInstrSize == 0);
+      ASSERT(call_size_in_bytes <= patch_size());
+      CodePatcher patcher(code->instruction_start() + last_pc_offset,
+                          call_size_in_words);
+      patcher.masm()->Call(deoptimization_entry, RelocInfo::NONE);
+      last_pc_offset += call_size_in_bytes;
+    }
+  }
+
+#ifdef DEBUG
+  // Destroy the code which is not supposed to be run again.
+  int instructions =
+      (code->safepoint_table_offset() - last_pc_offset) / Assembler::kInstrSize;
+  CodePatcher destroyer(code->instruction_start() + last_pc_offset,
+                        instructions);
+  for (int x = 0; x < instructions; x++) {
+    destroyer.masm()->break_(0);
+  }
+#endif
+
+  Isolate* isolate = code->GetIsolate();
+

[fschneider, 2011/10/18 14:27:58]

Remove extra new line.

[Paul Lind, 2011/10/19 02:18:27]

Done.

+
+  // Add the deoptimizing code to the list.
+  DeoptimizingCodeListNode* node = new DeoptimizingCodeListNode(code);
+  DeoptimizerData* data = isolate->deoptimizer_data();
+  node->set_next(data->deoptimizing_code_list_);
+  data->deoptimizing_code_list_ = node;
+
+  // We might be in the middle of incremental marking with compaction.
+  // Tell collector to treat this code object in a special way and
+  // ignore all slots that might have been recorded on it.
+  isolate->heap()->mark_compact_collector()->InvalidateCode(code);
+
+  // Set the code for the function to non-optimized version.
+  function->ReplaceCode(function->shared()->code());
+
+  if (FLAG_trace_deopt) {
+    PrintF("[forced deoptimization: ");
+    function->PrintName();
+    PrintF(" / %x]\n", reinterpret_cast<uint32_t>(function));
+#ifdef DEBUG
+    if (FLAG_print_code) {
+      code->PrintLn();
+    }
+#endif
+  }
+}
+
+
 void Deoptimizer::PatchStackCheckCodeAt(Code* unoptimized_code,
                                         Address pc_after,
                                         Code* check_code,
                                         Code* replacement_code) {
-  UNIMPLEMENTED();
+  const int kInstrSize = Assembler::kInstrSize;
+  // This structure comes from FullCodeGenerator::EmitStackCheck.
+  // The call of the stack guard check has the following form:
+  // sltu at, sp, t0
+  // beq at, zero_reg, ok
+  // lui t9, <stack guard address> upper
+  // ori t9, <stack guard address> lower
+  // jalr t9
+  // nop
+  // ----- pc_after points here
+
+  ASSERT(Assembler::IsBeq(Assembler::instr_at(pc_after - 5 * kInstrSize)));
+
+  // Replace the sltu instruction so beq is not executed.
+  CodePatcher patcher(pc_after - 6 * kInstrSize, 1);
+  patcher.masm()->addiu(at, zero_reg, 1);
+
+  Assembler::set_target_address_at(pc_after - 4 * kInstrSize,
+                                   replacement_code->entry());
+
+  // We patched the code to the following form:
+  // addiu at, zero_reg, 1
+  // beq at, zero_reg, ok  ;; Not changed
+  // lui t9, <on-stack replacement address> upper
+  // ori t9, <on-stack replacement address> lower
+  // jalr t9  ;; Not changed
+  // nop  ;; Not changed
+  // ----- pc_after points here

[fschneider, 2011/10/18 14:27:58]

With new GC I think you also need a write barrier here using RecordWriteIntoCode
(see ia32 and other platforms).

[Paul Lind, 2011/10/19 02:18:27]

Oops, we missed this. Thanks. Added it, and ported your refactoring from r9687.

Also, I added an ASSERT that seemed like a good idea, and updated some comments.

 }
 
 
 void Deoptimizer::RevertStackCheckCodeAt(Address pc_after,
                                          Code* check_code,
                                          Code* replacement_code) {
-  UNIMPLEMENTED();
+  // Exact opposite of the function above.
+  const int kInstrSize = Assembler::kInstrSize;
+  ASSERT(Assembler::IsAddImmediate(
+      Assembler::instr_at(pc_after - 6 * kInstrSize)));
+  ASSERT(Assembler::IsBeq(Assembler::instr_at(pc_after - 5 * kInstrSize)));
+
+  // Restore the sltu instruction so beq can possibly be executed again.
+  CodePatcher patcher(pc_after - 6 * kInstrSize, 1);
+  patcher.masm()->sltu(at, sp, t0);
+
+  Assembler::set_target_address_at(pc_after - 4 * kInstrSize,
+                                   check_code->entry());

[fschneider, 2011/10/18 14:27:58]

With new GC also insert call to write barrier here.

[Paul Lind, 2011/10/19 02:18:27]

Updated, as above.

+}
+
+
+static int LookupBailoutId(DeoptimizationInputData* data, unsigned ast_id) {
+  ByteArray* translations = data->TranslationByteArray();
+  int length = data->DeoptCount();
+  for (int i = 0; i < length; i++) {
+    if (static_cast<unsigned>(data->AstId(i)->value()) == 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() {
-  UNIMPLEMENTED();
-}
-
-
+  DeoptimizationInputData* data = DeoptimizationInputData::cast(
+      optimized_code_->deoptimization_data());
+  unsigned ast_id = data->OsrAstId()->value();
+
+  int bailout_id = LookupBailoutId(data, 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();
+  ASSERT(count == 1);
+  USE(count);
+
+  opcode = static_cast<Translation::Opcode>(iterator.Next());
+  USE(opcode);
+  ASSERT(Translation::FRAME == opcode);
+  unsigned node_id = iterator.Next();
+  USE(node_id);
+  ASSERT(node_id == ast_id);
+  JSFunction* function = JSFunction::cast(ComputeLiteral(iterator.Next()));
+  USE(function);
+  ASSERT(function == function_);
+  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 = optimized_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_));
+    function_->PrintName();
+    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_);
+#ifdef DEBUG
+  output_[0]->SetKind(Code::OPTIMIZED_FUNCTION);
+#endif
+
+  // 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<uint32_t>(from_));
+  } else {
+    // Setup 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();
+    uint32_t pc = reinterpret_cast<uint32_t>(
+        optimized_code_->entry() + pc_offset);
+    output_[0]->SetPc(pc);
+  }
+  Code* continuation = isolate_->builtins()->builtin(Builtins::kNotifyOSR);
+  output_[0]->SetContinuation(
+      reinterpret_cast<uint32_t>(continuation->entry()));
+
+  if (FLAG_trace_osr) {
+    PrintF("[on-stack replacement translation %s: 0x%08" V8PRIxPTR " ",
+           ok ? "finished" : "aborted",
+           reinterpret_cast<intptr_t>(function));
+    function->PrintName();
+    PrintF(" => pc=0x%0x]\n", output_[0]->GetPc());
+  }
+}
+
+
+// This code is very similar to ia32/arm code, but relies on register names
+// (fp, sp) and how the frame is laid out.
 void Deoptimizer::DoComputeFrame(TranslationIterator* iterator,
                                  int frame_index) {
-  UNIMPLEMENTED();
-}
-
+  // Read the ast node id, function, and frame height for this output frame.
+  Translation::Opcode opcode =
+      static_cast<Translation::Opcode>(iterator->Next());
+  USE(opcode);
+  ASSERT(Translation::FRAME == opcode);
+  int node_id = iterator->Next();
+  JSFunction* function = JSFunction::cast(ComputeLiteral(iterator->Next()));
+  unsigned height = iterator->Next();
+  unsigned height_in_bytes = height * kPointerSize;
+  if (FLAG_trace_deopt) {
+    PrintF("  translating ");
+    function->PrintName();
+    PrintF(" => node=%d, height=%d\n", node_id, height_in_bytes);
+  }
+
+  // The 'fixed' part of the frame consists of the incoming parameters and
+  // the part described by JavaScriptFrameConstants.
+  unsigned fixed_frame_size = ComputeFixedSize(function);
+  unsigned input_frame_size = input_->GetFrameSize();
+  unsigned output_frame_size = height_in_bytes + fixed_frame_size;
+
+  // Allocate and store the output frame description.
+  FrameDescription* output_frame =
+      new(output_frame_size) FrameDescription(output_frame_size, function);
+#ifdef DEBUG
+  output_frame->SetKind(Code::FUNCTION);
+#endif
+
+  bool is_bottommost = (0 == frame_index);
+  bool is_topmost = (output_count_ - 1 == frame_index);
+  ASSERT(frame_index >= 0 && frame_index < output_count_);
+  ASSERT(output_[frame_index] == NULL);
+  output_[frame_index] = output_frame;
+
+  // The top address for the bottommost output frame can be computed from
+  // the input frame pointer and the output frame's height.  For all
+  // subsequent output frames, it can be computed from the previous one's
+  // top address and the current frame's size.
+  uint32_t top_address;
+  if (is_bottommost) {
+    // 2 = context and function in the frame.
+    top_address =
+        input_->GetRegister(fp.code()) - (2 * kPointerSize) - height_in_bytes;
+  } else {
+    top_address = output_[frame_index - 1]->GetTop() - output_frame_size;
+  }
+  output_frame->SetTop(top_address);
+
+  // Compute the incoming parameter translation.
+  int parameter_count = function->shared()->formal_parameter_count() + 1;
+  unsigned output_offset = output_frame_size;
+  unsigned input_offset = input_frame_size;
+  for (int i = 0; i < parameter_count; ++i) {
+    output_offset -= kPointerSize;
+    DoTranslateCommand(iterator, frame_index, output_offset);
+  }
+  input_offset -= (parameter_count * kPointerSize);
+
+  // There are no translation commands for the caller's pc and fp, the
+  // context, and the function.  Synthesize their values and set them up
+  // explicitly.
+  //
+  // The caller's pc for the bottommost output frame is the same as in the
+  // input frame.  For all subsequent output frames, it can be read from the
+  // previous one.  This frame's pc can be computed from the non-optimized
+  // function code and AST id of the bailout.
+  output_offset -= kPointerSize;
+  input_offset -= kPointerSize;
+  intptr_t value;
+  if (is_bottommost) {
+    value = input_->GetFrameSlot(input_offset);
+  } else {
+    value = output_[frame_index - 1]->GetPc();
+  }
+  output_frame->SetFrameSlot(output_offset, value);
+  if (FLAG_trace_deopt) {
+    PrintF("    0x%08x: [top + %d] <- 0x%08x ; caller's pc\n",
+           top_address + output_offset, output_offset, value);
+  }
+
+  // The caller's frame pointer for the bottommost output frame is the same
+  // as in the input frame.  For all subsequent output frames, it can be
+  // read from the previous one.  Also compute and set this frame's frame
+  // pointer.
+  output_offset -= kPointerSize;
+  input_offset -= kPointerSize;
+  if (is_bottommost) {
+    value = input_->GetFrameSlot(input_offset);
+  } else {
+    value = output_[frame_index - 1]->GetFp();
+  }
+  output_frame->SetFrameSlot(output_offset, value);
+  intptr_t fp_value = top_address + output_offset;
+  ASSERT(!is_bottommost || input_->GetRegister(fp.code()) == fp_value);
+  output_frame->SetFp(fp_value);
+  if (is_topmost) {
+    output_frame->SetRegister(fp.code(), fp_value);
+  }
+  if (FLAG_trace_deopt) {
+    PrintF("    0x%08x: [top + %d] <- 0x%08x ; caller's fp\n",
+           fp_value, output_offset, value);
+  }
+
+  // For the bottommost output frame the context can be gotten from the input
+  // frame. For all subsequent output frames it can be gotten from the function
+  // so long as we don't inline functions that need local contexts.
+  output_offset -= kPointerSize;
+  input_offset -= kPointerSize;
+  if (is_bottommost) {
+    value = input_->GetFrameSlot(input_offset);
+  } else {
+    value = reinterpret_cast<intptr_t>(function->context());
+  }
+  output_frame->SetFrameSlot(output_offset, value);
+  if (is_topmost) {
+    output_frame->SetRegister(cp.code(), value);
+  }
+  if (FLAG_trace_deopt) {
+    PrintF("    0x%08x: [top + %d] <- 0x%08x ; context\n",
+           top_address + output_offset, output_offset, value);
+  }
+
+  // The function was mentioned explicitly in the BEGIN_FRAME.
+  output_offset -= kPointerSize;
+  input_offset -= kPointerSize;
+  value = reinterpret_cast<uint32_t>(function);
+  // The function for the bottommost output frame should also agree with the
+  // input frame.
+  ASSERT(!is_bottommost || input_->GetFrameSlot(input_offset) == value);
+  output_frame->SetFrameSlot(output_offset, value);
+  if (FLAG_trace_deopt) {
+    PrintF("    0x%08x: [top + %d] <- 0x%08x ; function\n",
+           top_address + output_offset, output_offset, value);
+  }
+
+  // Translate the rest of the frame.
+  for (unsigned i = 0; i < height; ++i) {
+    output_offset -= kPointerSize;
+    DoTranslateCommand(iterator, frame_index, output_offset);
+  }
+  ASSERT(0 == output_offset);
+
+  // Compute this frame's PC, state, and continuation.
+  Code* non_optimized_code = function->shared()->code();
+  FixedArray* raw_data = non_optimized_code->deoptimization_data();
+  DeoptimizationOutputData* data = DeoptimizationOutputData::cast(raw_data);
+  Address start = non_optimized_code->instruction_start();
+  unsigned pc_and_state = GetOutputInfo(data, node_id, function->shared());
+  unsigned pc_offset = FullCodeGenerator::PcField::decode(pc_and_state);
+  uint32_t pc_value = reinterpret_cast<uint32_t>(start + pc_offset);
+  output_frame->SetPc(pc_value);
+
+  FullCodeGenerator::State state =
+      FullCodeGenerator::StateField::decode(pc_and_state);
+  output_frame->SetState(Smi::FromInt(state));
+
+
+  // Set the continuation for the topmost frame.
+  if (is_topmost && bailout_type_ != DEBUGGER) {
+    Builtins* builtins = isolate_->builtins();
+    Code* continuation = (bailout_type_ == EAGER)
+        ? builtins->builtin(Builtins::kNotifyDeoptimized)
+        : builtins->builtin(Builtins::kNotifyLazyDeoptimized);
+    output_frame->SetContinuation(
+        reinterpret_cast<uint32_t>(continuation->entry()));
+  }
+}
 
 void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
-  UNIMPLEMENTED();
-}
-
-
+  // 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::kNumRegisters; i++) {
+    input_->SetRegister(i, i * 4);
+  }
+  input_->SetRegister(sp.code(), reinterpret_cast<intptr_t>(frame->sp()));
+  input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp()));
+  for (int i = 0; i < DoubleRegister::kNumAllocatableRegisters; i++) {
+    input_->SetDoubleRegister(i, 0.0);
+  }
+
+  // Fill the frame content from the actual data on the frame.
+  for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
+    input_->SetFrameSlot(i, Memory::uint32_at(tos + i));
+  }
+}
+
+
+#define __ masm()->
+
+
+// This code tries to be close to ia32 code so that any changes can be
+// easily ported.
 void Deoptimizer::EntryGenerator::Generate() {
-  UNIMPLEMENTED();
+  GeneratePrologue();
+
+  Isolate* isolate = masm()->isolate();
+
+  CpuFeatures::Scope scope(FPU);
+  // Unlike on ARM we don't save all the registers, just the useful ones.
+  // For the rest, there are gaps on the stack, so the offsets remain the same.
+  const int kNumberOfRegisters = Register::kNumRegisters;
+
+  RegList restored_regs = kJSCallerSaved | kCalleeSaved;
+  RegList saved_regs = restored_regs | sp.bit() | ra.bit();
+
+  const int kDoubleRegsSize =
+      kDoubleSize * FPURegister::kNumAllocatableRegisters;
+
+  // Save all FPU registers before messing with them.
+  __ Subu(sp, sp, Operand(kDoubleRegsSize));
+  for (int i = 0; i < FPURegister::kNumAllocatableRegisters; ++i) {
+    FPURegister fpu_reg = FPURegister::FromAllocationIndex(i);
+    int offset = i * kDoubleSize;
+    __ sdc1(fpu_reg, MemOperand(sp, offset));
+  }
+
+  // Push saved_regs (needed to populate FrameDescription::registers_).
+  // Leave gaps for other registers.
+  __ Subu(sp, sp, kNumberOfRegisters * kPointerSize);
+  for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
+    if ((saved_regs & (1 << i)) != 0) {
+      __ sw(ToRegister(i), MemOperand(sp, 4 * i));

[fschneider, 2011/10/18 14:27:58]

Maybe use kPointerSize instead of 4.

[Paul Lind, 2011/10/19 02:18:27]

Done.

+    }
+  }
+
+  const int kSavedRegistersAreaSize =
+      (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
+
+  // Get the bailout id from the stack.
+  __ lw(a2, MemOperand(sp, kSavedRegistersAreaSize));
+
+  // Get the address of the location in the code object if possible (a3) (return
+  // address for lazy deoptimization) and compute the fp-to-sp delta in
+  // register t0.
+  if (type() == EAGER) {
+    __ mov(a3, zero_reg);
+    // Correct one word for bailout id.
+    __ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
+  } else if (type() == OSR) {
+    __ mov(a3, ra);
+    // Correct one word for bailout id.
+    __ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
+  } else {
+    __ mov(a3, ra);
+    // Correct two words for bailout id and return address.
+    __ Addu(t0, sp, Operand(kSavedRegistersAreaSize + (2 * kPointerSize)));
+  }
+
+  __ Subu(t0, fp, t0);
+
+  // Allocate a new deoptimizer object.
+  // Pass four arguments in a0 to a3 and fifth & sixth arguments on stack.
+  __ PrepareCallCFunction(6, t1);
+  __ lw(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
+  __ li(a1, Operand(type()));  // bailout type,
+  // a2: bailout id already loaded.
+  // a3: code address or 0 already loaded.
+  __ sw(t0, CFunctionArgumentOperand(5));  // Fp-to-sp delta.
+  __ li(t1, Operand(ExternalReference::isolate_address()));
+  __ sw(t1, CFunctionArgumentOperand(6));  // Isolate.
+  // Call Deoptimizer::New().
+  {
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate), 6);
+  }
+
+  // Preserve "deoptimizer" object in register v0 and get the input
+  // frame descriptor pointer to a1 (deoptimizer->input_);
+  // Move deopt-obj to a0 for call to Deoptimizer::ComputeOutputFrames() below.
+  __ mov(a0, v0);
+  __ lw(a1, MemOperand(v0, Deoptimizer::input_offset()));
+
+  // Copy core registers into FrameDescription::registers_[kNumRegisters].
+  ASSERT(Register::kNumRegisters == kNumberOfRegisters);
+  for (int i = 0; i < kNumberOfRegisters; i++) {
+    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
+    if ((saved_regs & (1 << i)) != 0) {
+      __ lw(a2, MemOperand(sp, i * kPointerSize));
+      __ sw(a2, MemOperand(a1, offset));
+    } else if (FLAG_debug_code) {
+      __ li(a2, kDebugZapValue);
+      __ sw(a2, MemOperand(a1, offset));
+    }
+  }
+
+  // Copy FPU registers to
+  // double_registers_[DoubleRegister::kNumAllocatableRegisters]
+  int double_regs_offset = FrameDescription::double_registers_offset();
+  for (int i = 0; i < FPURegister::kNumAllocatableRegisters; ++i) {
+    int dst_offset = i * kDoubleSize + double_regs_offset;
+    int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
+    __ ldc1(f0, MemOperand(sp, src_offset));
+    __ sdc1(f0, MemOperand(a1, dst_offset));
+  }
+
+  // Remove the bailout id, eventually return address, and the saved registers
+  // from the stack.
+  if (type() == EAGER || type() == OSR) {
+    __ Addu(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
+  } else {
+    __ Addu(sp, sp, Operand(kSavedRegistersAreaSize + (2 * kPointerSize)));
+  }
+
+  // Compute a pointer to the unwinding limit in register a2; that is
+  // the first stack slot not part of the input frame.
+  __ lw(a2, MemOperand(a1, FrameDescription::frame_size_offset()));
+  __ Addu(a2, a2, sp);
+
+  // Unwind the stack down to - but not including - the unwinding
+  // limit and copy the contents of the activation frame to the input
+  // frame description.
+  __ Addu(a3, a1, Operand(FrameDescription::frame_content_offset()));
+  Label pop_loop;
+  __ bind(&pop_loop);
+  __ pop(t0);
+  __ sw(t0, MemOperand(a3, 0));
+  __ Branch(USE_DELAY_SLOT, &pop_loop, ne, a2, Operand(sp));
+  __ addiu(a3, a3, sizeof(uint32_t));  // In delay slot.
+
+  // Compute the output frame in the deoptimizer.
+  __ push(a0);  // Preserve deoptimizer object across call.
+  // a0: deoptimizer object; a1: scratch.
+  __ PrepareCallCFunction(1, a1);
+  // Call Deoptimizer::ComputeOutputFrames().
+  {
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(
+        ExternalReference::compute_output_frames_function(isolate), 1);
+  }
+  __ pop(a0);  // Restore deoptimizer object (class Deoptimizer).
+
+  // Replace the current (input) frame with the output frames.
+  Label outer_push_loop, inner_push_loop;
+  // Outer loop state: a0 = current "FrameDescription** output_",
+  // a1 = one past the last FrameDescription**.
+  __ lw(a1, MemOperand(a0, Deoptimizer::output_count_offset()));
+  __ lw(a0, MemOperand(a0, Deoptimizer::output_offset()));  // a0 is output_.
+  // __ add(r1, r0, Operand(r1, LSL, 2));

[fschneider, 2011/10/18 14:27:58]

Remove commented code. Looks as if this left over from the ARM file?

[Paul Lind, 2011/10/19 02:18:27]

Yep. A porting artifact, now removed.

+  __ sll(a1, a1, kPointerSizeLog2);  // Count to offset.
+  __ addu(a1, a0, a1);  // a1 = one past the last FrameDescription**.
+  __ bind(&outer_push_loop);
+  // Inner loop state: a2 = current FrameDescription*, a3 = loop index.
+  __ lw(a2, MemOperand(a0, 0));  // output_[ix]
+  __ lw(a3, MemOperand(a2, FrameDescription::frame_size_offset()));
+  __ bind(&inner_push_loop);
+  __ Subu(a3, a3, Operand(sizeof(uint32_t)));
+  __ Addu(t2, a2, Operand(a3));
+  __ lw(t3, MemOperand(t2, FrameDescription::frame_content_offset()));
+  __ push(t3);
+  __ Branch(&inner_push_loop, ne, a3, Operand(zero_reg));
+
+  __ Addu(a0, a0, Operand(kPointerSize));
+  __ Branch(&outer_push_loop, lt, a0, Operand(a1));
+
+
+  // Push state, pc, and continuation from the last output frame.
+  if (type() != OSR) {
+    __ lw(t2, MemOperand(a2, FrameDescription::state_offset()));
+    __ push(t2);
+  }
+
+  __ lw(t2, MemOperand(a2, FrameDescription::pc_offset()));
+  __ push(t2);
+  __ lw(t2, MemOperand(a2, FrameDescription::continuation_offset()));
+  __ push(t2);
+
+
+  // Technically restoring 'at' should work unless zero_reg is also restored
+  // but it's safer to check for this.
+  ASSERT(!(at.bit() & restored_regs));
+  // Restore the registers from the last output frame.
+  __ mov(at, a2);
+  for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
+    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
+    if ((restored_regs & (1 << i)) != 0) {
+      __ lw(ToRegister(i), MemOperand(at, offset));
+    }
+  }
+
+  // Set up the roots register.
+  ExternalReference roots_address = ExternalReference::roots_address(isolate);
+  __ li(roots, Operand(roots_address));
+
+  __ pop(at);  // Get continuation, leave pc on stack.
+  __ pop(ra);
+  __ Jump(at);
+  __ stop("Unreachable.");
 }
 
 
 void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
-  UNIMPLEMENTED();
-}
+  Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
+
+  // Create a sequence of deoptimization entries. Note that any
+  // registers may be still live.
+
+  Label done;
+  for (int i = 0; i < count(); i++) {
+    int start = masm()->pc_offset();
+    USE(start);
+    if (type() != EAGER) {
+      // Emulate ia32 like call by pushing return address to stack.
+      __ push(ra);
+    }
+    __ li(at, Operand(i));
+    __ push(at);
+    __ Branch(&done);
+
+    // Pad the rest of the code.
+    while (table_entry_size_ > (masm()->pc_offset() - start)) {
+      __ nop();
+    }
+
+    ASSERT_EQ(table_entry_size_, masm()->pc_offset() - start);
+  }
+  __ bind(&done);
+}
+
+#undef __
 
 
 } }  // namespace v8::internal