Remove some dead code.

src/x64/virtual-frame-x64.cc

Index: src/x64/virtual-frame-x64.cc
diff --git a/src/x64/virtual-frame-x64.cc b/src/x64/virtual-frame-x64.cc
deleted file mode 100644
index 10c327aa143e514fc7698e6a8c095bed30f5e0bb..0000000000000000000000000000000000000000
--- a/src/x64/virtual-frame-x64.cc
+++ /dev/null
@@ -1,1296 +0,0 @@
-// 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
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (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"
-
-#if defined(V8_TARGET_ARCH_X64)
-
-#include "codegen-inl.h"
-#include "register-allocator-inl.h"
-#include "scopes.h"
-#include "stub-cache.h"
-#include "virtual-frame-inl.h"
-
-namespace v8 {
-namespace internal {
-
-#define __ ACCESS_MASM(masm())
-
-void VirtualFrame::Enter() {
-  // Registers live on entry to a JS frame:
-  //   rsp: stack pointer, points to return address from this function.
-  //   rbp: base pointer, points to previous JS, ArgumentsAdaptor, or
-  //        Trampoline frame.
-  //   rsi: context of this function call.
-  //   rdi: pointer to this function object.
-  Comment cmnt(masm(), "[ Enter JS frame");
-
-#ifdef DEBUG
-  if (FLAG_debug_code) {
-    // Verify that rdi contains a JS function.  The following code
-    // relies on rax being available for use.
-    Condition not_smi = NegateCondition(masm()->CheckSmi(rdi));
-    __ Check(not_smi,
-             "VirtualFrame::Enter - rdi is not a function (smi check).");
-    __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rax);
-    __ Check(equal,
-             "VirtualFrame::Enter - rdi is not a function (map check).");
-  }
-#endif
-
-  EmitPush(rbp);
-
-  __ movq(rbp, rsp);
-
-  // Store the context in the frame.  The context is kept in rsi and a
-  // copy is stored in the frame.  The external reference to rsi
-  // remains.
-  EmitPush(rsi);
-
-  // Store the function in the frame.  The frame owns the register
-  // reference now (ie, it can keep it in rdi or spill it later).
-  Push(rdi);
-  SyncElementAt(element_count() - 1);
-  cgen()->allocator()->Unuse(rdi);
-}
-
-
-void VirtualFrame::Exit() {
-  Comment cmnt(masm(), "[ Exit JS frame");
-  // Record the location of the JS exit code for patching when setting
-  // break point.
-  __ RecordJSReturn();
-
-  // Avoid using the leave instruction here, because it is too
-  // short. We need the return sequence to be a least the size of a
-  // call instruction to support patching the exit code in the
-  // debugger. See GenerateReturnSequence for the full return sequence.
-  // TODO(X64): A patched call will be very long now.  Make sure we
-  // have enough room.
-  __ movq(rsp, rbp);
-  stack_pointer_ = frame_pointer();
-  for (int i = element_count() - 1; i > stack_pointer_; i--) {
-    FrameElement last = elements_.RemoveLast();
-    if (last.is_register()) {
-      Unuse(last.reg());
-    }
-  }
-
-  EmitPop(rbp);
-}
-
-
-void VirtualFrame::AllocateStackSlots() {
-  int count = local_count();
-  if (count > 0) {
-    Comment cmnt(masm(), "[ Allocate space for locals");
-    // The locals are initialized to a constant (the undefined value), but
-    // we sync them with the actual frame to allocate space for spilling
-    // them later.  First sync everything above the stack pointer so we can
-    // use pushes to allocate and initialize the locals.
-    SyncRange(stack_pointer_ + 1, element_count() - 1);
-    Handle<Object> undefined = FACTORY->undefined_value();
-    FrameElement initial_value =
-        FrameElement::ConstantElement(undefined, FrameElement::SYNCED);
-    if (count < kLocalVarBound) {
-      // For fewer locals the unrolled loop is more compact.
-
-      // Hope for one of the first eight registers, where the push operation
-      // takes only one byte (kScratchRegister needs the REX.W bit).
-      Result tmp = cgen()->allocator()->Allocate();
-      ASSERT(tmp.is_valid());
-      __ movq(tmp.reg(), undefined, RelocInfo::EMBEDDED_OBJECT);
-      for (int i = 0; i < count; i++) {
-        __ push(tmp.reg());
-      }
-    } else {
-      // For more locals a loop in generated code is more compact.
-      Label alloc_locals_loop;
-      Result cnt = cgen()->allocator()->Allocate();
-      ASSERT(cnt.is_valid());
-      __ movq(kScratchRegister, undefined, RelocInfo::EMBEDDED_OBJECT);
-#ifdef DEBUG
-      Label loop_size;
-      __ bind(&loop_size);
-#endif
-      if (is_uint8(count)) {
-        // Loading imm8 is shorter than loading imm32.
-        // Loading only partial byte register, and using decb below.
-        __ movb(cnt.reg(), Immediate(count));
-      } else {
-        __ movl(cnt.reg(), Immediate(count));
-      }
-      __ bind(&alloc_locals_loop);
-      __ push(kScratchRegister);
-      if (is_uint8(count)) {
-        __ decb(cnt.reg());
-      } else {
-        __ decl(cnt.reg());
-      }
-      __ j(not_zero, &alloc_locals_loop);
-#ifdef DEBUG
-      CHECK(masm()->SizeOfCodeGeneratedSince(&loop_size) < kLocalVarBound);
-#endif
-    }
-    for (int i = 0; i < count; i++) {
-      elements_.Add(initial_value);
-      stack_pointer_++;
-    }
-  }
-}
-
-
-void VirtualFrame::SaveContextRegister() {
-  ASSERT(elements_[context_index()].is_memory());
-  __ movq(Operand(rbp, fp_relative(context_index())), rsi);
-}
-
-
-void VirtualFrame::RestoreContextRegister() {
-  ASSERT(elements_[context_index()].is_memory());
-  __ movq(rsi, Operand(rbp, fp_relative(context_index())));
-}
-
-
-void VirtualFrame::PushReceiverSlotAddress() {
-  Result temp = cgen()->allocator()->Allocate();
-  ASSERT(temp.is_valid());
-  __ lea(temp.reg(), ParameterAt(-1));
-  Push(&temp);
-}
-
-
-void VirtualFrame::EmitPop(Register reg) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  stack_pointer_--;
-  elements_.RemoveLast();
-  __ pop(reg);
-}
-
-
-void VirtualFrame::EmitPop(const Operand& operand) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  stack_pointer_--;
-  elements_.RemoveLast();
-  __ pop(operand);
-}
-
-
-void VirtualFrame::EmitPush(Register reg, TypeInfo info) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  elements_.Add(FrameElement::MemoryElement(info));
-  stack_pointer_++;
-  __ push(reg);
-}
-
-
-void VirtualFrame::EmitPush(const Operand& operand, TypeInfo info) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  elements_.Add(FrameElement::MemoryElement(info));
-  stack_pointer_++;
-  __ push(operand);
-}
-
-
-void VirtualFrame::EmitPush(Immediate immediate, TypeInfo info) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  elements_.Add(FrameElement::MemoryElement(info));
-  stack_pointer_++;
-  __ push(immediate);
-}
-
-
-void VirtualFrame::EmitPush(Smi* smi_value) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  elements_.Add(FrameElement::MemoryElement(TypeInfo::Smi()));
-  stack_pointer_++;
-  __ Push(smi_value);
-}
-
-
-void VirtualFrame::EmitPush(Handle<Object> value) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  TypeInfo info = TypeInfo::TypeFromValue(value);
-  elements_.Add(FrameElement::MemoryElement(info));
-  stack_pointer_++;
-  __ Push(value);
-}
-
-
-void VirtualFrame::EmitPush(Heap::RootListIndex index, TypeInfo info) {
-  ASSERT(stack_pointer_ == element_count() - 1);
-  elements_.Add(FrameElement::MemoryElement(info));
-  stack_pointer_++;
-  __ PushRoot(index);
-}
-
-
-void VirtualFrame::Push(Expression* expr) {
-  ASSERT(expr->IsTrivial());
-
-  Literal* lit = expr->AsLiteral();
-  if (lit != NULL) {
-    Push(lit->handle());
-    return;
-  }
-
-  VariableProxy* proxy = expr->AsVariableProxy();
-  if (proxy != NULL) {
-    Slot* slot = proxy->var()->AsSlot();
-    if (slot->type() == Slot::LOCAL) {
-      PushLocalAt(slot->index());
-      return;
-    }
-    if (slot->type() == Slot::PARAMETER) {
-      PushParameterAt(slot->index());
-      return;
-    }
-  }
-  UNREACHABLE();
-}
-
-
-void VirtualFrame::Push(Handle<Object> value) {
-  if (ConstantPoolOverflowed()) {
-    Result temp = cgen()->allocator()->Allocate();
-    ASSERT(temp.is_valid());
-    if (value->IsSmi()) {
-      __ Move(temp.reg(), Smi::cast(*value));
-    } else {
-      __ movq(temp.reg(), value, RelocInfo::EMBEDDED_OBJECT);
-    }
-    Push(&temp);
-  } else {
-    FrameElement element =
-        FrameElement::ConstantElement(value, FrameElement::NOT_SYNCED);
-    elements_.Add(element);
-  }
-}
-
-
-void VirtualFrame::Drop(int count) {
-  ASSERT(count >= 0);
-  ASSERT(height() >= count);
-  int num_virtual_elements = (element_count() - 1) - stack_pointer_;
-
-  // Emit code to lower the stack pointer if necessary.
-  if (num_virtual_elements < count) {
-    int num_dropped = count - num_virtual_elements;
-    stack_pointer_ -= num_dropped;
-    __ addq(rsp, Immediate(num_dropped * kPointerSize));
-  }
-
-  // Discard elements from the virtual frame and free any registers.
-  for (int i = 0; i < count; i++) {
-    FrameElement dropped = elements_.RemoveLast();
-    if (dropped.is_register()) {
-      Unuse(dropped.reg());
-    }
-  }
-}
-
-
-int VirtualFrame::InvalidateFrameSlotAt(int index) {
-  FrameElement original = elements_[index];
-
-  // Is this element the backing store of any copies?
-  int new_backing_index = kIllegalIndex;
-  if (original.is_copied()) {
-    // Verify it is copied, and find first copy.
-    for (int i = index + 1; i < element_count(); i++) {
-      if (elements_[i].is_copy() && elements_[i].index() == index) {
-        new_backing_index = i;
-        break;
-      }
-    }
-  }
-
-  if (new_backing_index == kIllegalIndex) {
-    // No copies found, return kIllegalIndex.
-    if (original.is_register()) {
-      Unuse(original.reg());
-    }
-    elements_[index] = FrameElement::InvalidElement();
-    return kIllegalIndex;
-  }
-
-  // This is the backing store of copies.
-  Register backing_reg;
-  if (original.is_memory()) {
-    Result fresh = cgen()->allocator()->Allocate();
-    ASSERT(fresh.is_valid());
-    Use(fresh.reg(), new_backing_index);
-    backing_reg = fresh.reg();
-    __ movq(backing_reg, Operand(rbp, fp_relative(index)));
-  } else {
-    // The original was in a register.
-    backing_reg = original.reg();
-    set_register_location(backing_reg, new_backing_index);
-  }
-  // Invalidate the element at index.
-  elements_[index] = FrameElement::InvalidElement();
-  // Set the new backing element.
-  if (elements_[new_backing_index].is_synced()) {
-    elements_[new_backing_index] =
-        FrameElement::RegisterElement(backing_reg,
-                                      FrameElement::SYNCED,
-                                      original.type_info());
-  } else {
-    elements_[new_backing_index] =
-        FrameElement::RegisterElement(backing_reg,
-                                      FrameElement::NOT_SYNCED,
-                                      original.type_info());
-  }
-  // Update the other copies.
-  for (int i = new_backing_index + 1; i < element_count(); i++) {
-    if (elements_[i].is_copy() && elements_[i].index() == index) {
-      elements_[i].set_index(new_backing_index);
-      elements_[new_backing_index].set_copied();
-    }
-  }
-  return new_backing_index;
-}
-
-
-void VirtualFrame::TakeFrameSlotAt(int index) {
-  ASSERT(index >= 0);
-  ASSERT(index <= element_count());
-  FrameElement original = elements_[index];
-  int new_backing_store_index = InvalidateFrameSlotAt(index);
-  if (new_backing_store_index != kIllegalIndex) {
-    elements_.Add(CopyElementAt(new_backing_store_index));
-    return;
-  }
-
-  switch (original.type()) {
-    case FrameElement::MEMORY: {
-      // Emit code to load the original element's data into a register.
-      // Push that register as a FrameElement on top of the frame.
-      Result fresh = cgen()->allocator()->Allocate();
-      ASSERT(fresh.is_valid());
-      FrameElement new_element =
-          FrameElement::RegisterElement(fresh.reg(),
-                                        FrameElement::NOT_SYNCED,
-                                        original.type_info());
-      Use(fresh.reg(), element_count());
-      elements_.Add(new_element);
-      __ movq(fresh.reg(), Operand(rbp, fp_relative(index)));
-      break;
-    }
-    case FrameElement::REGISTER:
-      Use(original.reg(), element_count());
-      // Fall through.
-    case FrameElement::CONSTANT:
-    case FrameElement::COPY:
-      original.clear_sync();
-      elements_.Add(original);
-      break;
-    case FrameElement::INVALID:
-      UNREACHABLE();
-      break;
-  }
-}
-
-
-void VirtualFrame::StoreToFrameSlotAt(int index) {
-  // Store the value on top of the frame to the virtual frame slot at
-  // a given index.  The value on top of the frame is left in place.
-  // This is a duplicating operation, so it can create copies.
-  ASSERT(index >= 0);
-  ASSERT(index < element_count());
-
-  int top_index = element_count() - 1;
-  FrameElement top = elements_[top_index];
-  FrameElement original = elements_[index];
-  if (top.is_copy() && top.index() == index) return;
-  ASSERT(top.is_valid());
-
-  InvalidateFrameSlotAt(index);
-
-  // InvalidateFrameSlotAt can potentially change any frame element, due
-  // to spilling registers to allocate temporaries in order to preserve
-  // the copy-on-write semantics of aliased elements.  Reload top from
-  // the frame.
-  top = elements_[top_index];
-
-  if (top.is_copy()) {
-    // There are two cases based on the relative positions of the
-    // stored-to slot and the backing slot of the top element.
-    int backing_index = top.index();
-    ASSERT(backing_index != index);
-    if (backing_index < index) {
-      // 1. The top element is a copy of a slot below the stored-to
-      // slot.  The stored-to slot becomes an unsynced copy of that
-      // same backing slot.
-      elements_[index] = CopyElementAt(backing_index);
-    } else {
-      // 2. The top element is a copy of a slot above the stored-to
-      // slot.  The stored-to slot becomes the new (unsynced) backing
-      // slot and both the top element and the element at the former
-      // backing slot become copies of it.  The sync state of the top
-      // and former backing elements is preserved.
-      FrameElement backing_element = elements_[backing_index];
-      ASSERT(backing_element.is_memory() || backing_element.is_register());
-      if (backing_element.is_memory()) {
-        // Because sets of copies are canonicalized to be backed by
-        // their lowest frame element, and because memory frame
-        // elements are backed by the corresponding stack address, we
-        // have to move the actual value down in the stack.
-        //
-        // TODO(209): considering allocating the stored-to slot to the
-        // temp register.  Alternatively, allow copies to appear in
-        // any order in the frame and lazily move the value down to
-        // the slot.
-        __ movq(kScratchRegister, Operand(rbp, fp_relative(backing_index)));
-        __ movq(Operand(rbp, fp_relative(index)), kScratchRegister);
-      } else {
-        set_register_location(backing_element.reg(), index);
-        if (backing_element.is_synced()) {
-          // If the element is a register, we will not actually move
-          // anything on the stack but only update the virtual frame
-          // element.
-          backing_element.clear_sync();
-        }
-      }
-      elements_[index] = backing_element;
-
-      // The old backing element becomes a copy of the new backing
-      // element.
-      FrameElement new_element = CopyElementAt(index);
-      elements_[backing_index] = new_element;
-      if (backing_element.is_synced()) {
-        elements_[backing_index].set_sync();
-      }
-
-      // All the copies of the old backing element (including the top
-      // element) become copies of the new backing element.
-      for (int i = backing_index + 1; i < element_count(); i++) {
-        if (elements_[i].is_copy() && elements_[i].index() == backing_index) {
-          elements_[i].set_index(index);
-        }
-      }
-    }
-    return;
-  }
-
-  // Move the top element to the stored-to slot and replace it (the
-  // top element) with a copy.
-  elements_[index] = top;
-  if (top.is_memory()) {
-    // TODO(209): consider allocating the stored-to slot to the temp
-    // register.  Alternatively, allow copies to appear in any order
-    // in the frame and lazily move the value down to the slot.
-    FrameElement new_top = CopyElementAt(index);
-    new_top.set_sync();
-    elements_[top_index] = new_top;
-
-    // The sync state of the former top element is correct (synced).
-    // Emit code to move the value down in the frame.
-    __ movq(kScratchRegister, Operand(rsp, 0));
-    __ movq(Operand(rbp, fp_relative(index)), kScratchRegister);
-  } else if (top.is_register()) {
-    set_register_location(top.reg(), index);
-    // The stored-to slot has the (unsynced) register reference and
-    // the top element becomes a copy.  The sync state of the top is
-    // preserved.
-    FrameElement new_top = CopyElementAt(index);
-    if (top.is_synced()) {
-      new_top.set_sync();
-      elements_[index].clear_sync();
-    }
-    elements_[top_index] = new_top;
-  } else {
-    // The stored-to slot holds the same value as the top but
-    // unsynced.  (We do not have copies of constants yet.)
-    ASSERT(top.is_constant());
-    elements_[index].clear_sync();
-  }
-}
-
-
-void VirtualFrame::MakeMergable() {
-  for (int i = 0; i < element_count(); i++) {
-    FrameElement element = elements_[i];
-
-    // In all cases we have to reset the number type information
-    // to unknown for a mergable frame because of incoming back edges.
-    if (element.is_constant() || element.is_copy()) {
-      if (element.is_synced()) {
-        // Just spill.
-        elements_[i] = FrameElement::MemoryElement(TypeInfo::Unknown());
-      } else {
-        // Allocate to a register.
-        FrameElement backing_element;  // Invalid if not a copy.
-        if (element.is_copy()) {
-          backing_element = elements_[element.index()];
-        }
-        Result fresh = cgen()->allocator()->Allocate();
-        ASSERT(fresh.is_valid());  // A register was spilled if all were in use.
-        elements_[i] =
-            FrameElement::RegisterElement(fresh.reg(),
-                                          FrameElement::NOT_SYNCED,
-                                          TypeInfo::Unknown());
-        Use(fresh.reg(), i);
-
-        // Emit a move.
-        if (element.is_constant()) {
-          __ Move(fresh.reg(), element.handle());
-        } else {
-          ASSERT(element.is_copy());
-          // Copies are only backed by register or memory locations.
-          if (backing_element.is_register()) {
-            // The backing store may have been spilled by allocating,
-            // but that's OK.  If it was, the value is right where we
-            // want it.
-            if (!fresh.reg().is(backing_element.reg())) {
-              __ movq(fresh.reg(), backing_element.reg());
-            }
-          } else {
-            ASSERT(backing_element.is_memory());
-            __ movq(fresh.reg(), Operand(rbp, fp_relative(element.index())));
-          }
-        }
-      }
-      // No need to set the copied flag --- there are no copies.
-    } else {
-      // Clear the copy flag of non-constant, non-copy elements.
-      // They cannot be copied because copies are not allowed.
-      // The copy flag is not relied on before the end of this loop,
-      // including when registers are spilled.
-      elements_[i].clear_copied();
-      elements_[i].set_type_info(TypeInfo::Unknown());
-    }
-  }
-}
-
-
-void VirtualFrame::MergeTo(VirtualFrame* expected) {
-  Comment cmnt(masm(), "[ Merge frame");
-  // We should always be merging the code generator's current frame to an
-  // expected frame.
-  ASSERT(cgen()->frame() == this);
-
-  // Adjust the stack pointer upward (toward the top of the virtual
-  // frame) if necessary.
-  if (stack_pointer_ < expected->stack_pointer_) {
-    int difference = expected->stack_pointer_ - stack_pointer_;
-    stack_pointer_ = expected->stack_pointer_;
-    __ subq(rsp, Immediate(difference * kPointerSize));
-  }
-
-  MergeMoveRegistersToMemory(expected);
-  MergeMoveRegistersToRegisters(expected);
-  MergeMoveMemoryToRegisters(expected);
-
-  // Adjust the stack pointer downward if necessary.
-  if (stack_pointer_ > expected->stack_pointer_) {
-    int difference = stack_pointer_ - expected->stack_pointer_;
-    stack_pointer_ = expected->stack_pointer_;
-    __ addq(rsp, Immediate(difference * kPointerSize));
-  }
-
-  // At this point, the frames should be identical.
-  ASSERT(Equals(expected));
-}
-
-
-void VirtualFrame::MergeMoveRegistersToMemory(VirtualFrame* expected) {
-  ASSERT(stack_pointer_ >= expected->stack_pointer_);
-
-  // Move registers, constants, and copies to memory.  Perform moves
-  // from the top downward in the frame in order to leave the backing
-  // stores of copies in registers.
-  for (int i = element_count() - 1; i >= 0; i--) {
-    FrameElement target = expected->elements_[i];
-    if (target.is_register()) continue;  // Handle registers later.
-    if (target.is_memory()) {
-      FrameElement source = elements_[i];
-      switch (source.type()) {
-        case FrameElement::INVALID:
-          // Not a legal merge move.
-          UNREACHABLE();
-          break;
-
-        case FrameElement::MEMORY:
-          // Already in place.
-          break;
-
-        case FrameElement::REGISTER:
-          Unuse(source.reg());
-          if (!source.is_synced()) {
-            __ movq(Operand(rbp, fp_relative(i)), source.reg());
-          }
-          break;
-
-        case FrameElement::CONSTANT:
-          if (!source.is_synced()) {
-            __ Move(Operand(rbp, fp_relative(i)), source.handle());
-          }
-          break;
-
-        case FrameElement::COPY:
-          if (!source.is_synced()) {
-            int backing_index = source.index();
-            FrameElement backing_element = elements_[backing_index];
-            if (backing_element.is_memory()) {
-              __ movq(kScratchRegister,
-                       Operand(rbp, fp_relative(backing_index)));
-              __ movq(Operand(rbp, fp_relative(i)), kScratchRegister);
-            } else {
-              ASSERT(backing_element.is_register());
-              __ movq(Operand(rbp, fp_relative(i)), backing_element.reg());
-            }
-          }
-          break;
-      }
-    }
-    elements_[i] = target;
-  }
-}
-
-
-void VirtualFrame::MergeMoveRegistersToRegisters(VirtualFrame* expected) {
-  // We have already done X-to-memory moves.
-  ASSERT(stack_pointer_ >= expected->stack_pointer_);
-
-  for (int i = 0; i < RegisterAllocator::kNumRegisters; i++) {
-    // Move the right value into register i if it is currently in a register.
-    int index = expected->register_location(i);
-    int use_index = register_location(i);
-    // Skip if register i is unused in the target or else if source is
-    // not a register (this is not a register-to-register move).
-    if (index == kIllegalIndex || !elements_[index].is_register()) continue;
-
-    Register target = RegisterAllocator::ToRegister(i);
-    Register source = elements_[index].reg();
-    if (index != use_index) {
-      if (use_index == kIllegalIndex) {  // Target is currently unused.
-        // Copy contents of source from source to target.
-        // Set frame element register to target.
-        Use(target, index);
-        Unuse(source);
-        __ movq(target, source);
-      } else {
-        // Exchange contents of registers source and target.
-        // Nothing except the register backing use_index has changed.
-        elements_[use_index].set_reg(source);
-        set_register_location(target, index);
-        set_register_location(source, use_index);
-        __ xchg(source, target);
-      }
-    }
-
-    if (!elements_[index].is_synced() &&
-        expected->elements_[index].is_synced()) {
-      __ movq(Operand(rbp, fp_relative(index)), target);
-    }
-    elements_[index] = expected->elements_[index];
-  }
-}
-
-
-void VirtualFrame::MergeMoveMemoryToRegisters(VirtualFrame* expected) {
-  // Move memory, constants, and copies to registers.  This is the
-  // final step and since it is not done from the bottom up, but in
-  // register code order, we have special code to ensure that the backing
-  // elements of copies are in their correct locations when we
-  // encounter the copies.
-  for (int i = 0; i < RegisterAllocator::kNumRegisters; i++) {
-    int index = expected->register_location(i);
-    if (index != kIllegalIndex) {
-      FrameElement source = elements_[index];
-      FrameElement target = expected->elements_[index];
-      Register target_reg = RegisterAllocator::ToRegister(i);
-      ASSERT(target.reg().is(target_reg));
-      switch (source.type()) {
-        case FrameElement::INVALID:  // Fall through.
-          UNREACHABLE();
-          break;
-        case FrameElement::REGISTER:
-          ASSERT(source.Equals(target));
-          // Go to next iteration.  Skips Use(target_reg) and syncing
-          // below.  It is safe to skip syncing because a target
-          // register frame element would only be synced if all source
-          // elements were.
-          continue;
-          break;
-        case FrameElement::MEMORY:
-          ASSERT(index <= stack_pointer_);
-          __ movq(target_reg, Operand(rbp, fp_relative(index)));
-          break;
-
-        case FrameElement::CONSTANT:
-          __ Move(target_reg, source.handle());
-          break;
-
-        case FrameElement::COPY: {
-          int backing_index = source.index();
-          FrameElement backing = elements_[backing_index];
-          ASSERT(backing.is_memory() || backing.is_register());
-          if (backing.is_memory()) {
-            ASSERT(backing_index <= stack_pointer_);
-            // Code optimization if backing store should also move
-            // to a register: move backing store to its register first.
-            if (expected->elements_[backing_index].is_register()) {
-              FrameElement new_backing = expected->elements_[backing_index];
-              Register new_backing_reg = new_backing.reg();
-              ASSERT(!is_used(new_backing_reg));
-              elements_[backing_index] = new_backing;
-              Use(new_backing_reg, backing_index);
-              __ movq(new_backing_reg,
-                      Operand(rbp, fp_relative(backing_index)));
-              __ movq(target_reg, new_backing_reg);
-            } else {
-              __ movq(target_reg, Operand(rbp, fp_relative(backing_index)));
-            }
-          } else {
-            __ movq(target_reg, backing.reg());
-          }
-        }
-      }
-      // Ensure the proper sync state.
-      if (target.is_synced() && !source.is_synced()) {
-        __ movq(Operand(rbp, fp_relative(index)), target_reg);
-      }
-      Use(target_reg, index);
-      elements_[index] = target;
-    }
-  }
-}
-
-
-Result VirtualFrame::Pop() {
-  FrameElement element = elements_.RemoveLast();
-  int index = element_count();
-  ASSERT(element.is_valid());
-
-  // Get number type information of the result.
-  TypeInfo info;
-  if (!element.is_copy()) {
-    info = element.type_info();
-  } else {
-    info = elements_[element.index()].type_info();
-  }
-
-  bool pop_needed = (stack_pointer_ == index);
-  if (pop_needed) {
-    stack_pointer_--;
-    if (element.is_memory()) {
-      Result temp = cgen()->allocator()->Allocate();
-      ASSERT(temp.is_valid());
-      __ pop(temp.reg());
-      temp.set_type_info(info);
-      return temp;
-    }
-
-    __ addq(rsp, Immediate(kPointerSize));
-  }
-  ASSERT(!element.is_memory());
-
-  // The top element is a register, constant, or a copy.  Unuse
-  // registers and follow copies to their backing store.
-  if (element.is_register()) {
-    Unuse(element.reg());
-  } else if (element.is_copy()) {
-    ASSERT(element.index() < index);
-    index = element.index();
-    element = elements_[index];
-  }
-  ASSERT(!element.is_copy());
-
-  // The element is memory, a register, or a constant.
-  if (element.is_memory()) {
-    // Memory elements could only be the backing store of a copy.
-    // Allocate the original to a register.
-    ASSERT(index <= stack_pointer_);
-    Result temp = cgen()->allocator()->Allocate();
-    ASSERT(temp.is_valid());
-    Use(temp.reg(), index);
-    FrameElement new_element =
-        FrameElement::RegisterElement(temp.reg(),
-                                      FrameElement::SYNCED,
-                                      element.type_info());
-    // Preserve the copy flag on the element.
-    if (element.is_copied()) new_element.set_copied();
-    elements_[index] = new_element;
-    __ movq(temp.reg(), Operand(rbp, fp_relative(index)));
-    return Result(temp.reg(), info);
-  } else if (element.is_register()) {
-    return Result(element.reg(), info);
-  } else {
-    ASSERT(element.is_constant());
-    return Result(element.handle());
-  }
-}
-
-
-Result VirtualFrame::RawCallStub(CodeStub* stub) {
-  ASSERT(cgen()->HasValidEntryRegisters());
-  __ CallStub(stub);
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-  return result;
-}
-
-
-Result VirtualFrame::CallStub(CodeStub* stub, Result* arg) {
-  PrepareForCall(0, 0);
-  arg->ToRegister(rax);
-  arg->Unuse();
-  return RawCallStub(stub);
-}
-
-
-Result VirtualFrame::CallStub(CodeStub* stub, Result* arg0, Result* arg1) {
-  PrepareForCall(0, 0);
-
-  if (arg0->is_register() && arg0->reg().is(rax)) {
-    if (arg1->is_register() && arg1->reg().is(rdx)) {
-      // Wrong registers.
-      __ xchg(rax, rdx);
-    } else {
-      // Register rdx is free for arg0, which frees rax for arg1.
-      arg0->ToRegister(rdx);
-      arg1->ToRegister(rax);
-    }
-  } else {
-    // Register rax is free for arg1, which guarantees rdx is free for
-    // arg0.
-    arg1->ToRegister(rax);
-    arg0->ToRegister(rdx);
-  }
-
-  arg0->Unuse();
-  arg1->Unuse();
-  return RawCallStub(stub);
-}
-
-
-Result VirtualFrame::CallJSFunction(int arg_count) {
-  Result function = Pop();
-
-  // InvokeFunction requires function in rdi.  Move it in there.
-  function.ToRegister(rdi);
-  function.Unuse();
-
-  // +1 for receiver.
-  PrepareForCall(arg_count + 1, arg_count + 1);
-  ASSERT(cgen()->HasValidEntryRegisters());
-  ParameterCount count(arg_count);
-  __ InvokeFunction(rdi, count, CALL_FUNCTION);
-  RestoreContextRegister();
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-  return result;
-}
-
-
-void VirtualFrame::SyncElementBelowStackPointer(int index) {
-  // Emit code to write elements below the stack pointer to their
-  // (already allocated) stack address.
-  ASSERT(index <= stack_pointer_);
-  FrameElement element = elements_[index];
-  ASSERT(!element.is_synced());
-  switch (element.type()) {
-    case FrameElement::INVALID:
-      break;
-
-    case FrameElement::MEMORY:
-      // This function should not be called with synced elements.
-      // (memory elements are always synced).
-      UNREACHABLE();
-      break;
-
-    case FrameElement::REGISTER:
-      __ movq(Operand(rbp, fp_relative(index)), element.reg());
-      break;
-
-    case FrameElement::CONSTANT:
-      __ Move(Operand(rbp, fp_relative(index)), element.handle());
-      break;
-
-    case FrameElement::COPY: {
-      int backing_index = element.index();
-      FrameElement backing_element = elements_[backing_index];
-      if (backing_element.is_memory()) {
-        __ movq(kScratchRegister, Operand(rbp, fp_relative(backing_index)));
-        __ movq(Operand(rbp, fp_relative(index)), kScratchRegister);
-      } else {
-        ASSERT(backing_element.is_register());
-        __ movq(Operand(rbp, fp_relative(index)), backing_element.reg());
-      }
-      break;
-    }
-  }
-  elements_[index].set_sync();
-}
-
-
-void VirtualFrame::SyncElementByPushing(int index) {
-  // Sync an element of the frame that is just above the stack pointer
-  // by pushing it.
-  ASSERT(index == stack_pointer_ + 1);
-  stack_pointer_++;
-  FrameElement element = elements_[index];
-
-  switch (element.type()) {
-    case FrameElement::INVALID:
-      __ Push(Smi::FromInt(0));
-      break;
-
-    case FrameElement::MEMORY:
-      // No memory elements exist above the stack pointer.
-      UNREACHABLE();
-      break;
-
-    case FrameElement::REGISTER:
-      __ push(element.reg());
-      break;
-
-    case FrameElement::CONSTANT:
-      __ Move(kScratchRegister, element.handle());
-      __ push(kScratchRegister);
-      break;
-
-    case FrameElement::COPY: {
-      int backing_index = element.index();
-      FrameElement backing = elements_[backing_index];
-      ASSERT(backing.is_memory() || backing.is_register());
-      if (backing.is_memory()) {
-        __ push(Operand(rbp, fp_relative(backing_index)));
-      } else {
-        __ push(backing.reg());
-      }
-      break;
-    }
-  }
-  elements_[index].set_sync();
-}
-
-
-// Clear the dirty bits for the range of elements in
-// [min(stack_pointer_ + 1,begin), end].
-void VirtualFrame::SyncRange(int begin, int end) {
-  ASSERT(begin >= 0);
-  ASSERT(end < element_count());
-  // Sync elements below the range if they have not been materialized
-  // on the stack.
-  int start = Min(begin, stack_pointer_ + 1);
-  int end_or_stack_pointer = Min(stack_pointer_, end);
-  // Emit normal push instructions for elements above stack pointer
-  // and use mov instructions if we are below stack pointer.
-  int i = start;
-
-  while (i <= end_or_stack_pointer) {
-    if (!elements_[i].is_synced()) SyncElementBelowStackPointer(i);
-    i++;
-  }
-  while (i <= end) {
-    SyncElementByPushing(i);
-    i++;
-  }
-}
-
-
-//------------------------------------------------------------------------------
-// Virtual frame stub and IC calling functions.
-
-Result VirtualFrame::CallRuntime(const Runtime::Function* f, int arg_count) {
-  PrepareForCall(arg_count, arg_count);
-  ASSERT(cgen()->HasValidEntryRegisters());
-  __ CallRuntime(f, arg_count);
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-  return result;
-}
-
-
-Result VirtualFrame::CallRuntime(Runtime::FunctionId id, int arg_count) {
-  PrepareForCall(arg_count, arg_count);
-  ASSERT(cgen()->HasValidEntryRegisters());
-  __ CallRuntime(id, arg_count);
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-  return result;
-}
-
-
-#ifdef ENABLE_DEBUGGER_SUPPORT
-void VirtualFrame::DebugBreak() {
-  PrepareForCall(0, 0);
-  ASSERT(cgen()->HasValidEntryRegisters());
-  __ DebugBreak();
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-}
-#endif
-
-
-Result VirtualFrame::InvokeBuiltin(Builtins::JavaScript id,
-                                   InvokeFlag flag,
-                                   int arg_count) {
-  PrepareForCall(arg_count, arg_count);
-  ASSERT(cgen()->HasValidEntryRegisters());
-  __ InvokeBuiltin(id, flag);
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-  return result;
-}
-
-
-Result VirtualFrame::RawCallCodeObject(Handle<Code> code,
-                                       RelocInfo::Mode rmode) {
-  ASSERT(cgen()->HasValidEntryRegisters());
-  __ Call(code, rmode);
-  Result result = cgen()->allocator()->Allocate(rax);
-  ASSERT(result.is_valid());
-  return result;
-}
-
-
-// This function assumes that the only results that could be in a_reg or b_reg
-// are a and b.  Other results can be live, but must not be in a_reg or b_reg.
-void VirtualFrame::MoveResultsToRegisters(Result* a,
-                                          Result* b,
-                                          Register a_reg,
-                                          Register b_reg) {
-  ASSERT(!a_reg.is(b_reg));
-  // Assert that cgen()->allocator()->count(a_reg) is accounted for by a and b.
-  ASSERT(cgen()->allocator()->count(a_reg) <= 2);
-  ASSERT(cgen()->allocator()->count(a_reg) != 2 || a->reg().is(a_reg));
-  ASSERT(cgen()->allocator()->count(a_reg) != 2 || b->reg().is(a_reg));
-  ASSERT(cgen()->allocator()->count(a_reg) != 1 ||
-         (a->is_register() && a->reg().is(a_reg)) ||
-         (b->is_register() && b->reg().is(a_reg)));
-  // Assert that cgen()->allocator()->count(b_reg) is accounted for by a and b.
-  ASSERT(cgen()->allocator()->count(b_reg) <= 2);
-  ASSERT(cgen()->allocator()->count(b_reg) != 2 || a->reg().is(b_reg));
-  ASSERT(cgen()->allocator()->count(b_reg) != 2 || b->reg().is(b_reg));
-  ASSERT(cgen()->allocator()->count(b_reg) != 1 ||
-         (a->is_register() && a->reg().is(b_reg)) ||
-         (b->is_register() && b->reg().is(b_reg)));
-
-  if (a->is_register() && a->reg().is(a_reg)) {
-    b->ToRegister(b_reg);
-  } else if (!cgen()->allocator()->is_used(a_reg)) {
-    a->ToRegister(a_reg);
-    b->ToRegister(b_reg);
-  } else if (cgen()->allocator()->is_used(b_reg)) {
-    // a must be in b_reg, b in a_reg.
-    __ xchg(a_reg, b_reg);
-    // Results a and b will be invalidated, so it is ok if they are switched.
-  } else {
-    b->ToRegister(b_reg);
-    a->ToRegister(a_reg);
-  }
-  a->Unuse();
-  b->Unuse();
-}
-
-
-Result VirtualFrame::CallLoadIC(RelocInfo::Mode mode) {
-  // Name and receiver are on the top of the frame.  Both are dropped.
-  // The IC expects name in rcx and receiver in rax.
-  Handle<Code> ic(Isolate::Current()->builtins()->builtin(
-      Builtins::kLoadIC_Initialize));
-  Result name = Pop();
-  Result receiver = Pop();
-  PrepareForCall(0, 0);
-  MoveResultsToRegisters(&name, &receiver, rcx, rax);
-
-  return RawCallCodeObject(ic, mode);
-}
-
-
-Result VirtualFrame::CallKeyedLoadIC(RelocInfo::Mode mode) {
-  // Key and receiver are on top of the frame. Put them in rax and rdx.
-  Result key = Pop();
-  Result receiver = Pop();
-  PrepareForCall(0, 0);
-  MoveResultsToRegisters(&key, &receiver, rax, rdx);
-
-  Handle<Code> ic(Isolate::Current()->builtins()->builtin(
-      Builtins::kKeyedLoadIC_Initialize));
-  return RawCallCodeObject(ic, mode);
-}
-
-
-Result VirtualFrame::CallStoreIC(Handle<String> name,
-                                 bool is_contextual,
-                                 StrictModeFlag strict_mode) {
-  // Value and (if not contextual) receiver are on top of the frame.
-  // The IC expects name in rcx, value in rax, and receiver in rdx.
-  Handle<Code> ic(Isolate::Current()->builtins()->builtin(
-      (strict_mode == kStrictMode) ? Builtins::kStoreIC_Initialize_Strict
-                                   : Builtins::kStoreIC_Initialize));
-  Result value = Pop();
-  RelocInfo::Mode mode;
-  if (is_contextual) {
-    PrepareForCall(0, 0);
-    value.ToRegister(rax);
-    __ movq(rdx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
-    value.Unuse();
-    mode = RelocInfo::CODE_TARGET_CONTEXT;
-  } else {
-    Result receiver = Pop();
-    PrepareForCall(0, 0);
-    MoveResultsToRegisters(&value, &receiver, rax, rdx);
-    mode = RelocInfo::CODE_TARGET;
-  }
-  __ Move(rcx, name);
-  return RawCallCodeObject(ic, mode);
-}
-
-
-Result VirtualFrame::CallKeyedStoreIC(StrictModeFlag strict_mode) {
-  // Value, key, and receiver are on the top of the frame.  The IC
-  // expects value in rax, key in rcx, and receiver in rdx.
-  Result value = Pop();
-  Result key = Pop();
-  Result receiver = Pop();
-  PrepareForCall(0, 0);
-  if (!cgen()->allocator()->is_used(rax) ||
-      (value.is_register() && value.reg().is(rax))) {
-    if (!cgen()->allocator()->is_used(rax)) {
-      value.ToRegister(rax);
-    }
-    MoveResultsToRegisters(&key, &receiver, rcx, rdx);
-    value.Unuse();
-  } else if (!cgen()->allocator()->is_used(rcx) ||
-             (key.is_register() && key.reg().is(rcx))) {
-    if (!cgen()->allocator()->is_used(rcx)) {
-      key.ToRegister(rcx);
-    }
-    MoveResultsToRegisters(&value, &receiver, rax, rdx);
-    key.Unuse();
-  } else if (!cgen()->allocator()->is_used(rdx) ||
-             (receiver.is_register() && receiver.reg().is(rdx))) {
-    if (!cgen()->allocator()->is_used(rdx)) {
-      receiver.ToRegister(rdx);
-    }
-    MoveResultsToRegisters(&key, &value, rcx, rax);
-    receiver.Unuse();
-  } else {
-    // All three registers are used, and no value is in the correct place.
-    // We have one of the two circular permutations of rax, rcx, rdx.
-    ASSERT(value.is_register());
-    if (value.reg().is(rcx)) {
-      __ xchg(rax, rdx);
-      __ xchg(rax, rcx);
-    } else {
-      __ xchg(rax, rcx);
-      __ xchg(rax, rdx);
-    }
-    value.Unuse();
-    key.Unuse();
-    receiver.Unuse();
-  }
-
-  Handle<Code> ic(Isolate::Current()->builtins()->builtin(
-      (strict_mode == kStrictMode) ? Builtins::kKeyedStoreIC_Initialize_Strict
-                                   : Builtins::kKeyedStoreIC_Initialize));
-  return RawCallCodeObject(ic, RelocInfo::CODE_TARGET);
-}
-
-
-Result VirtualFrame::CallCallIC(RelocInfo::Mode mode,
-                                int arg_count,
-                                int loop_nesting) {
-  // Function name, arguments, and receiver are found on top of the frame
-  // and dropped by the call.  The IC expects the name in rcx and the rest
-  // on the stack, and drops them all.
-  InLoopFlag in_loop = loop_nesting > 0 ? IN_LOOP : NOT_IN_LOOP;
-  Handle<Code> ic =
-      ISOLATE->stub_cache()->ComputeCallInitialize(arg_count, in_loop);
-  Result name = Pop();
-  // Spill args, receiver, and function.  The call will drop args and
-  // receiver.
-  PrepareForCall(arg_count + 1, arg_count + 1);
-  name.ToRegister(rcx);
-  name.Unuse();
-  return RawCallCodeObject(ic, mode);
-}
-
-
-Result VirtualFrame::CallKeyedCallIC(RelocInfo::Mode mode,
-                                     int arg_count,
-                                     int loop_nesting) {
-  // Function name, arguments, and receiver are found on top of the frame
-  // and dropped by the call.  The IC expects the name in rcx and the rest
-  // on the stack, and drops them all.
-  InLoopFlag in_loop = loop_nesting > 0 ? IN_LOOP : NOT_IN_LOOP;
-  Handle<Code> ic =
-      ISOLATE->stub_cache()->ComputeKeyedCallInitialize(arg_count, in_loop);
-  Result name = Pop();
-  // Spill args, receiver, and function.  The call will drop args and
-  // receiver.
-  PrepareForCall(arg_count + 1, arg_count + 1);
-  name.ToRegister(rcx);
-  name.Unuse();
-  return RawCallCodeObject(ic, mode);
-}
-
-
-Result VirtualFrame::CallConstructor(int arg_count) {
-  // Arguments, receiver, and function are on top of the frame.  The
-  // IC expects arg count in rax, function in rdi, and the arguments
-  // and receiver on the stack.
-  Handle<Code> ic(Isolate::Current()->builtins()->builtin(
-      Builtins::kJSConstructCall));
-  // Duplicate the function before preparing the frame.
-  PushElementAt(arg_count);
-  Result function = Pop();
-  PrepareForCall(arg_count + 1, arg_count + 1);  // Spill function and args.
-  function.ToRegister(rdi);
-
-  // Constructors are called with the number of arguments in register
-  // rax for now. Another option would be to have separate construct
-  // call trampolines per different arguments counts encountered.
-  Result num_args = cgen()->allocator()->Allocate(rax);
-  ASSERT(num_args.is_valid());
-  __ Set(num_args.reg(), arg_count);
-
-  function.Unuse();
-  num_args.Unuse();
-  return RawCallCodeObject(ic, RelocInfo::CONSTRUCT_CALL);
-}
-
-
-void VirtualFrame::PushTryHandler(HandlerType type) {
-  ASSERT(cgen()->HasValidEntryRegisters());
-  // Grow the expression stack by handler size less one (the return
-  // address is already pushed by a call instruction).
-  Adjust(kHandlerSize - 1);
-  __ PushTryHandler(IN_JAVASCRIPT, type);
-}
-
-
-#undef __
-
-} }  // namespace v8::internal
-
-#endif  // V8_TARGET_ARCH_X64