310fd67aea
Review URL: http://codereview.chromium.org/126198 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2204 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
526 lines
17 KiB
C++
526 lines
17 KiB
C++
// Copyright 2009 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "v8.h"
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#include "codegen-inl.h"
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#include "register-allocator-inl.h"
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#include "scopes.h"
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namespace v8 {
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namespace internal {
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#define __ ACCESS_MASM(masm())
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// -------------------------------------------------------------------------
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// VirtualFrame implementation.
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// On entry to a function, the virtual frame already contains the receiver,
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// the parameters, and a return address. All frame elements are in memory.
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VirtualFrame::VirtualFrame()
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: elements_(parameter_count() + local_count() + kPreallocatedElements),
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stack_pointer_(parameter_count() + 1) { // 0-based index of TOS.
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for (int i = 0; i <= stack_pointer_; i++) {
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elements_.Add(FrameElement::MemoryElement());
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}
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for (int i = 0; i < RegisterAllocator::kNumRegisters; i++) {
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register_locations_[i] = kIllegalIndex;
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}
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}
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void VirtualFrame::Enter() {
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// Registers live on entry to a JS frame:
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// rsp: stack pointer, points to return address from this function.
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// rbp: base pointer, points to previous JS, ArgumentsAdaptor, or
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// Trampoline frame.
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// rsi: context of this function call.
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// rdi: pointer to this function object.
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Comment cmnt(masm(), "[ Enter JS frame");
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#ifdef DEBUG
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// Verify that rdi contains a JS function. The following code
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// relies on rax being available for use.
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__ testq(rdi, Immediate(kSmiTagMask));
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__ Check(not_zero,
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"VirtualFrame::Enter - rdi is not a function (smi check).");
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__ CmpObjectType(rdi, JS_FUNCTION_TYPE, rax);
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__ Check(equal,
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"VirtualFrame::Enter - rdi is not a function (map check).");
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#endif
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EmitPush(rbp);
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__ movq(rbp, rsp);
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// Store the context in the frame. The context is kept in rsi and a
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// copy is stored in the frame. The external reference to rsi
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// remains.
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EmitPush(rsi);
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// Store the function in the frame. The frame owns the register
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// reference now (ie, it can keep it in rdi or spill it later).
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Push(rdi);
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SyncElementAt(element_count() - 1);
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cgen()->allocator()->Unuse(rdi);
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}
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void VirtualFrame::Exit() {
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Comment cmnt(masm(), "[ Exit JS frame");
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// Record the location of the JS exit code for patching when setting
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// break point.
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__ RecordJSReturn();
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// Avoid using the leave instruction here, because it is too
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// short. We need the return sequence to be a least the size of a
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// call instruction to support patching the exit code in the
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// debugger. See GenerateReturnSequence for the full return sequence.
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// TODO(X64): A patched call will be very long now. Make sure we
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// have enough room.
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__ movq(rsp, rbp);
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stack_pointer_ = frame_pointer();
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for (int i = element_count() - 1; i > stack_pointer_; i--) {
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FrameElement last = elements_.RemoveLast();
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if (last.is_register()) {
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Unuse(last.reg());
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}
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}
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EmitPop(rbp);
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}
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void VirtualFrame::AllocateStackSlots() {
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int count = local_count();
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if (count > 0) {
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Comment cmnt(masm(), "[ Allocate space for locals");
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// The locals are initialized to a constant (the undefined value), but
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// we sync them with the actual frame to allocate space for spilling
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// them later. First sync everything above the stack pointer so we can
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// use pushes to allocate and initialize the locals.
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SyncRange(stack_pointer_ + 1, element_count() - 1);
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Handle<Object> undefined = Factory::undefined_value();
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FrameElement initial_value =
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FrameElement::ConstantElement(undefined, FrameElement::SYNCED);
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__ movq(kScratchRegister, undefined, RelocInfo::EMBEDDED_OBJECT);
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for (int i = 0; i < count; i++) {
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elements_.Add(initial_value);
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stack_pointer_++;
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__ push(kScratchRegister);
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}
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}
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}
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void VirtualFrame::EmitPop(Register reg) {
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ASSERT(stack_pointer_ == element_count() - 1);
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stack_pointer_--;
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elements_.RemoveLast();
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__ pop(reg);
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}
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void VirtualFrame::EmitPop(const Operand& operand) {
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ASSERT(stack_pointer_ == element_count() - 1);
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stack_pointer_--;
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elements_.RemoveLast();
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__ pop(operand);
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}
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void VirtualFrame::EmitPush(Register reg) {
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ASSERT(stack_pointer_ == element_count() - 1);
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elements_.Add(FrameElement::MemoryElement());
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stack_pointer_++;
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__ push(reg);
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}
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void VirtualFrame::EmitPush(const Operand& operand) {
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ASSERT(stack_pointer_ == element_count() - 1);
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elements_.Add(FrameElement::MemoryElement());
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stack_pointer_++;
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__ push(operand);
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}
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void VirtualFrame::EmitPush(Immediate immediate) {
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ASSERT(stack_pointer_ == element_count() - 1);
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elements_.Add(FrameElement::MemoryElement());
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stack_pointer_++;
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__ push(immediate);
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}
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void VirtualFrame::Drop(int count) {
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ASSERT(height() >= count);
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int num_virtual_elements = (element_count() - 1) - stack_pointer_;
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// Emit code to lower the stack pointer if necessary.
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if (num_virtual_elements < count) {
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int num_dropped = count - num_virtual_elements;
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stack_pointer_ -= num_dropped;
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__ addq(rsp, Immediate(num_dropped * kPointerSize));
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}
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// Discard elements from the virtual frame and free any registers.
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for (int i = 0; i < count; i++) {
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FrameElement dropped = elements_.RemoveLast();
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if (dropped.is_register()) {
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Unuse(dropped.reg());
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}
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}
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}
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int VirtualFrame::InvalidateFrameSlotAt(int index) {
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FrameElement original = elements_[index];
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// Is this element the backing store of any copies?
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int new_backing_index = kIllegalIndex;
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if (original.is_copied()) {
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// Verify it is copied, and find first copy.
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for (int i = index + 1; i < element_count(); i++) {
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if (elements_[i].is_copy() && elements_[i].index() == index) {
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new_backing_index = i;
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break;
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}
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}
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}
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if (new_backing_index == kIllegalIndex) {
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// No copies found, return kIllegalIndex.
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if (original.is_register()) {
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Unuse(original.reg());
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}
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elements_[index] = FrameElement::InvalidElement();
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return kIllegalIndex;
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}
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// This is the backing store of copies.
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Register backing_reg;
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if (original.is_memory()) {
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Result fresh = cgen()->allocator()->Allocate();
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ASSERT(fresh.is_valid());
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Use(fresh.reg(), new_backing_index);
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backing_reg = fresh.reg();
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__ movq(backing_reg, Operand(rbp, fp_relative(index)));
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} else {
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// The original was in a register.
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backing_reg = original.reg();
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set_register_location(backing_reg, new_backing_index);
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}
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// Invalidate the element at index.
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elements_[index] = FrameElement::InvalidElement();
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// Set the new backing element.
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if (elements_[new_backing_index].is_synced()) {
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elements_[new_backing_index] =
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FrameElement::RegisterElement(backing_reg, FrameElement::SYNCED);
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} else {
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elements_[new_backing_index] =
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FrameElement::RegisterElement(backing_reg, FrameElement::NOT_SYNCED);
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}
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// Update the other copies.
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for (int i = new_backing_index + 1; i < element_count(); i++) {
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if (elements_[i].is_copy() && elements_[i].index() == index) {
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elements_[i].set_index(new_backing_index);
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elements_[new_backing_index].set_copied();
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}
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}
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return new_backing_index;
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}
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void VirtualFrame::StoreToFrameSlotAt(int index) {
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// Store the value on top of the frame to the virtual frame slot at
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// a given index. The value on top of the frame is left in place.
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// This is a duplicating operation, so it can create copies.
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ASSERT(index >= 0);
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ASSERT(index < element_count());
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int top_index = element_count() - 1;
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FrameElement top = elements_[top_index];
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FrameElement original = elements_[index];
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if (top.is_copy() && top.index() == index) return;
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ASSERT(top.is_valid());
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InvalidateFrameSlotAt(index);
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// InvalidateFrameSlotAt can potentially change any frame element, due
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// to spilling registers to allocate temporaries in order to preserve
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// the copy-on-write semantics of aliased elements. Reload top from
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// the frame.
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top = elements_[top_index];
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if (top.is_copy()) {
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// There are two cases based on the relative positions of the
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// stored-to slot and the backing slot of the top element.
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int backing_index = top.index();
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ASSERT(backing_index != index);
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if (backing_index < index) {
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// 1. The top element is a copy of a slot below the stored-to
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// slot. The stored-to slot becomes an unsynced copy of that
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// same backing slot.
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elements_[index] = CopyElementAt(backing_index);
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} else {
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// 2. The top element is a copy of a slot above the stored-to
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// slot. The stored-to slot becomes the new (unsynced) backing
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// slot and both the top element and the element at the former
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// backing slot become copies of it. The sync state of the top
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// and former backing elements is preserved.
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FrameElement backing_element = elements_[backing_index];
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ASSERT(backing_element.is_memory() || backing_element.is_register());
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if (backing_element.is_memory()) {
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// Because sets of copies are canonicalized to be backed by
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// their lowest frame element, and because memory frame
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// elements are backed by the corresponding stack address, we
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// have to move the actual value down in the stack.
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//
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// TODO(209): considering allocating the stored-to slot to the
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// temp register. Alternatively, allow copies to appear in
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// any order in the frame and lazily move the value down to
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// the slot.
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__ movq(kScratchRegister, Operand(rbp, fp_relative(backing_index)));
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__ movq(Operand(rbp, fp_relative(index)), kScratchRegister);
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} else {
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set_register_location(backing_element.reg(), index);
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if (backing_element.is_synced()) {
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// If the element is a register, we will not actually move
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// anything on the stack but only update the virtual frame
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// element.
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backing_element.clear_sync();
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}
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}
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elements_[index] = backing_element;
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// The old backing element becomes a copy of the new backing
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// element.
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FrameElement new_element = CopyElementAt(index);
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elements_[backing_index] = new_element;
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if (backing_element.is_synced()) {
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elements_[backing_index].set_sync();
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}
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// All the copies of the old backing element (including the top
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// element) become copies of the new backing element.
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for (int i = backing_index + 1; i < element_count(); i++) {
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if (elements_[i].is_copy() && elements_[i].index() == backing_index) {
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elements_[i].set_index(index);
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}
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}
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}
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return;
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}
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// Move the top element to the stored-to slot and replace it (the
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// top element) with a copy.
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elements_[index] = top;
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if (top.is_memory()) {
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// TODO(209): consider allocating the stored-to slot to the temp
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// register. Alternatively, allow copies to appear in any order
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// in the frame and lazily move the value down to the slot.
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FrameElement new_top = CopyElementAt(index);
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new_top.set_sync();
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elements_[top_index] = new_top;
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// The sync state of the former top element is correct (synced).
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// Emit code to move the value down in the frame.
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__ movq(kScratchRegister, Operand(rsp, 0));
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__ movq(Operand(rbp, fp_relative(index)), kScratchRegister);
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} else if (top.is_register()) {
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set_register_location(top.reg(), index);
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// The stored-to slot has the (unsynced) register reference and
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// the top element becomes a copy. The sync state of the top is
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// preserved.
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FrameElement new_top = CopyElementAt(index);
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if (top.is_synced()) {
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new_top.set_sync();
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elements_[index].clear_sync();
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}
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elements_[top_index] = new_top;
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} else {
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// The stored-to slot holds the same value as the top but
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// unsynced. (We do not have copies of constants yet.)
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ASSERT(top.is_constant());
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elements_[index].clear_sync();
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}
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}
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void VirtualFrame::MergeTo(VirtualFrame* a) {
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UNIMPLEMENTED();
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}
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Result VirtualFrame::Pop() {
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FrameElement element = elements_.RemoveLast();
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int index = element_count();
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ASSERT(element.is_valid());
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bool pop_needed = (stack_pointer_ == index);
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if (pop_needed) {
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stack_pointer_--;
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if (element.is_memory()) {
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Result temp = cgen()->allocator()->Allocate();
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ASSERT(temp.is_valid());
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temp.set_static_type(element.static_type());
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__ pop(temp.reg());
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return temp;
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}
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__ addq(rsp, Immediate(kPointerSize));
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}
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ASSERT(!element.is_memory());
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// The top element is a register, constant, or a copy. Unuse
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// registers and follow copies to their backing store.
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if (element.is_register()) {
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Unuse(element.reg());
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} else if (element.is_copy()) {
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ASSERT(element.index() < index);
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index = element.index();
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element = elements_[index];
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}
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ASSERT(!element.is_copy());
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// The element is memory, a register, or a constant.
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if (element.is_memory()) {
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// Memory elements could only be the backing store of a copy.
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// Allocate the original to a register.
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ASSERT(index <= stack_pointer_);
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Result temp = cgen()->allocator()->Allocate();
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ASSERT(temp.is_valid());
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Use(temp.reg(), index);
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FrameElement new_element =
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FrameElement::RegisterElement(temp.reg(), FrameElement::SYNCED);
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// Preserve the copy flag on the element.
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if (element.is_copied()) new_element.set_copied();
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new_element.set_static_type(element.static_type());
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elements_[index] = new_element;
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__ movq(temp.reg(), Operand(rbp, fp_relative(index)));
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return Result(temp.reg(), element.static_type());
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} else if (element.is_register()) {
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return Result(element.reg(), element.static_type());
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} else {
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ASSERT(element.is_constant());
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return Result(element.handle());
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}
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}
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Result VirtualFrame::RawCallStub(CodeStub* a) {
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UNIMPLEMENTED();
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return Result(NULL);
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}
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void VirtualFrame::SyncElementBelowStackPointer(int a) {
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UNIMPLEMENTED();
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}
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void VirtualFrame::SyncElementByPushing(int index) {
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// Sync an element of the frame that is just above the stack pointer
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// by pushing it.
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ASSERT(index == stack_pointer_ + 1);
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stack_pointer_++;
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FrameElement element = elements_[index];
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switch (element.type()) {
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case FrameElement::INVALID:
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__ push(Immediate(Smi::FromInt(0)));
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break;
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case FrameElement::MEMORY:
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// No memory elements exist above the stack pointer.
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UNREACHABLE();
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break;
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case FrameElement::REGISTER:
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__ push(element.reg());
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break;
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case FrameElement::CONSTANT:
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if (element.handle()->IsSmi()) {
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if (CodeGeneratorScope::Current()->IsUnsafeSmi(element.handle())) {
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CodeGeneratorScope::Current()->LoadUnsafeSmi(kScratchRegister,
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element.handle());
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} else {
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CodeGeneratorScope::Current()->masm()->
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movq(kScratchRegister, element.handle(), RelocInfo::NONE);
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}
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} else {
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CodeGeneratorScope::Current()->masm()->
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movq(kScratchRegister,
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element.handle(),
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RelocInfo::EMBEDDED_OBJECT);
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}
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__ push(kScratchRegister);
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break;
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case FrameElement::COPY: {
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int backing_index = element.index();
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FrameElement backing = elements_[backing_index];
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ASSERT(backing.is_memory() || backing.is_register());
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if (backing.is_memory()) {
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__ push(Operand(rbp, fp_relative(backing_index)));
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} else {
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__ push(backing.reg());
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}
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break;
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}
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}
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elements_[index].set_sync();
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}
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// Clear the dirty bits for the range of elements in
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// [min(stack_pointer_ + 1,begin), end].
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void VirtualFrame::SyncRange(int begin, int end) {
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ASSERT(begin >= 0);
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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);
|
|
|
|
// If positive we have to adjust the stack pointer.
|
|
int delta = end - stack_pointer_;
|
|
if (delta > 0) {
|
|
stack_pointer_ = end;
|
|
__ subq(rsp, Immediate(delta * kPointerSize));
|
|
}
|
|
|
|
for (int i = start; i <= end; i++) {
|
|
if (!elements_[i].is_synced()) SyncElementBelowStackPointer(i);
|
|
}
|
|
}
|
|
|
|
|
|
#undef __
|
|
|
|
} } // namespace v8::internal
|