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// Copyright 2010 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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// * 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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// 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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#if defined(V8_TARGET_ARCH_X64)
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#include "codegen-inl.h"
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#include "jump-target-inl.h"
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#include "register-allocator-inl.h"
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#include "virtual-frame-inl.h"
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// -------------------------------------------------------------------------
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// JumpTarget implementation.
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#define __ ACCESS_MASM(cgen()->masm())
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void JumpTarget::DoJump() {
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ASSERT(cgen()->has_valid_frame());
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// Live non-frame registers are not allowed at unconditional jumps
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// because we have no way of invalidating the corresponding results
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// which are still live in the C++ code.
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ASSERT(cgen()->HasValidEntryRegisters());
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// Backward jump. There is an expected frame to merge to.
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ASSERT(direction_ == BIDIRECTIONAL);
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cgen()->frame()->PrepareMergeTo(entry_frame_);
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cgen()->frame()->MergeTo(entry_frame_);
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cgen()->DeleteFrame();
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__ jmp(&entry_label_);
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} else if (entry_frame_ != NULL) {
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// Forward jump with a preconfigured entry frame. Assert the
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// current frame matches the expected one and jump to the block.
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ASSERT(cgen()->frame()->Equals(entry_frame_));
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cgen()->DeleteFrame();
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__ jmp(&entry_label_);
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// Forward jump. Remember the current frame and emit a jump to
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AddReachingFrame(cgen()->frame());
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cgen()->SetFrame(NULL, &empty);
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__ jmp(&merge_labels_.last());
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void JumpTarget::DoBranch(Condition cc, Hint b) {
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ASSERT(cgen() != NULL);
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ASSERT(cgen()->has_valid_frame());
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ASSERT(direction_ == BIDIRECTIONAL);
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// Backward branch. We have an expected frame to merge to on the
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// Swap the current frame for a copy (we do the swapping to get
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// the off-frame registers off the fall through) to use for the
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VirtualFrame* fall_through_frame = cgen()->frame();
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VirtualFrame* branch_frame = new VirtualFrame(fall_through_frame);
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RegisterFile non_frame_registers;
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cgen()->SetFrame(branch_frame, &non_frame_registers);
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// Check if we can avoid merge code.
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cgen()->frame()->PrepareMergeTo(entry_frame_);
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if (cgen()->frame()->Equals(entry_frame_)) {
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// Branch right in to the block.
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cgen()->DeleteFrame();
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__ j(cc, &entry_label_);
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cgen()->SetFrame(fall_through_frame, &non_frame_registers);
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// Check if we can reuse existing merge code.
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for (int i = 0; i < reaching_frames_.length(); i++) {
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if (reaching_frames_[i] != NULL &&
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cgen()->frame()->Equals(reaching_frames_[i])) {
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// Branch to the merge code.
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cgen()->DeleteFrame();
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__ j(cc, &merge_labels_[i]);
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cgen()->SetFrame(fall_through_frame, &non_frame_registers);
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// To emit the merge code here, we negate the condition and branch
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// around the merge code on the fall through path.
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Label original_fall_through;
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__ j(NegateCondition(cc), &original_fall_through);
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cgen()->frame()->MergeTo(entry_frame_);
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cgen()->DeleteFrame();
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__ jmp(&entry_label_);
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cgen()->SetFrame(fall_through_frame, &non_frame_registers);
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__ bind(&original_fall_through);
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} else if (entry_frame_ != NULL) {
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// Forward branch with a preconfigured entry frame. Assert the
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// current frame matches the expected one and branch to the block.
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ASSERT(cgen()->frame()->Equals(entry_frame_));
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// Explicitly use the macro assembler instead of __ as forward
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// branches are expected to be a fixed size (no inserted
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// coverage-checking instructions please). This is used in
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// Reference::GetValue.
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cgen()->masm()->j(cc, &entry_label_);
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// Forward branch. A copy of the current frame is remembered and
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// a branch to the merge code is emitted. Explicitly use the
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// macro assembler instead of __ as forward branches are expected
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// to be a fixed size (no inserted coverage-checking instructions
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// please). This is used in Reference::GetValue.
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AddReachingFrame(new VirtualFrame(cgen()->frame()));
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cgen()->masm()->j(cc, &merge_labels_.last());
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void JumpTarget::Call() {
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// Call is used to push the address of the catch block on the stack as
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// a return address when compiling try/catch and try/finally. We
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// fully spill the frame before making the call. The expected frame
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// at the label (which should be the only one) is the spilled current
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// frame plus an in-memory return address. The "fall-through" frame
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// at the return site is the spilled current frame.
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ASSERT(cgen() != NULL);
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ASSERT(cgen()->has_valid_frame());
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// There are no non-frame references across the call.
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ASSERT(cgen()->HasValidEntryRegisters());
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ASSERT(!is_linked());
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cgen()->frame()->SpillAll();
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VirtualFrame* target_frame = new VirtualFrame(cgen()->frame());
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target_frame->Adjust(1);
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// We do not expect a call with a preconfigured entry frame.
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ASSERT(entry_frame_ == NULL);
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AddReachingFrame(target_frame);
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__ call(&merge_labels_.last());
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void JumpTarget::DoBind() {
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ASSERT(cgen() != NULL);
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// Live non-frame registers are not allowed at the start of a basic
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ASSERT(!cgen()->has_valid_frame() || cgen()->HasValidEntryRegisters());
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// Fast case: the jump target was manually configured with an entry
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if (entry_frame_ != NULL) {
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// Assert no reaching frames to deal with.
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ASSERT(reaching_frames_.is_empty());
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ASSERT(!cgen()->has_valid_frame());
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if (direction_ == BIDIRECTIONAL) {
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// Copy the entry frame so the original can be used for a
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// possible backward jump.
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cgen()->SetFrame(new VirtualFrame(entry_frame_), &empty);
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// Take ownership of the entry frame.
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cgen()->SetFrame(entry_frame_, &empty);
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__ bind(&entry_label_);
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ASSERT(cgen()->has_valid_frame());
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if (direction_ == FORWARD_ONLY) {
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// Fast case: no forward jumps and no possible backward jumps.
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// The stack pointer can be floating above the top of the
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// virtual frame before the bind. Afterward, it should not.
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VirtualFrame* frame = cgen()->frame();
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int difference = frame->stack_pointer_ - (frame->element_count() - 1);
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if (difference > 0) {
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frame->stack_pointer_ -= difference;
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__ addq(rsp, Immediate(difference * kPointerSize));
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ASSERT(direction_ == BIDIRECTIONAL);
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// Fast case: no forward jumps, possible backward ones. Remove
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// constants and copies above the watermark on the fall-through
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// frame and use it as the entry frame.
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cgen()->frame()->MakeMergable();
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entry_frame_ = new VirtualFrame(cgen()->frame());
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__ bind(&entry_label_);
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if (direction_ == FORWARD_ONLY &&
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!cgen()->has_valid_frame() &&
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reaching_frames_.length() == 1) {
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// Fast case: no fall-through, a single forward jump, and no
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// possible backward jumps. Pick up the only reaching frame, take
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// ownership of it, and use it for the block about to be emitted.
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VirtualFrame* frame = reaching_frames_[0];
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cgen()->SetFrame(frame, &empty);
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reaching_frames_[0] = NULL;
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__ bind(&merge_labels_[0]);
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// The stack pointer can be floating above the top of the
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// virtual frame before the bind. Afterward, it should not.
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int difference = frame->stack_pointer_ - (frame->element_count() - 1);
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if (difference > 0) {
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frame->stack_pointer_ -= difference;
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__ addq(rsp, Immediate(difference * kPointerSize));
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__ bind(&entry_label_);
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// If there is a current frame, record it as the fall-through. It
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// is owned by the reaching frames for now.
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bool had_fall_through = false;
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if (cgen()->has_valid_frame()) {
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had_fall_through = true;
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AddReachingFrame(cgen()->frame()); // Return value ignored.
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cgen()->SetFrame(NULL, &empty);
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// Compute the frame to use for entry to the block.
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// Some moves required to merge to an expected frame require purely
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// frame state changes, and do not require any code generation.
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// Perform those first to increase the possibility of finding equal
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for (int i = 0; i < reaching_frames_.length(); i++) {
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if (reaching_frames_[i] != NULL) {
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reaching_frames_[i]->PrepareMergeTo(entry_frame_);
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// There were forward jumps. Handle merging the reaching frames
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// to the entry frame.
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// Loop over the (non-null) reaching frames and process any that
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// need merge code. Iterate backwards through the list to handle
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// the fall-through frame first. Set frames that will be
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// processed after 'i' to NULL if we want to avoid processing
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for (int i = reaching_frames_.length() - 1; i >= 0; i--) {
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VirtualFrame* frame = reaching_frames_[i];
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// Does the frame (probably) need merge code?
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if (!frame->Equals(entry_frame_)) {
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// We could have a valid frame as the fall through to the
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// binding site or as the fall through from a previous merge
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// code block. Jump around the code we are about to
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if (cgen()->has_valid_frame()) {
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cgen()->DeleteFrame();
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__ jmp(&entry_label_);
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// Pick up the frame for this block. Assume ownership if
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// there cannot be backward jumps.
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if (direction_ == BIDIRECTIONAL) {
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cgen()->SetFrame(new VirtualFrame(frame), &empty);
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cgen()->SetFrame(frame, &empty);
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reaching_frames_[i] = NULL;
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__ bind(&merge_labels_[i]);
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// Loop over the remaining (non-null) reaching frames,
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// looking for any that can share merge code with this one.
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for (int j = 0; j < i; j++) {
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VirtualFrame* other = reaching_frames_[j];
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if (other != NULL && other->Equals(cgen()->frame())) {
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// Set the reaching frame element to null to avoid
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// processing it later, and then bind its entry label.
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reaching_frames_[j] = NULL;
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__ bind(&merge_labels_[j]);
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// Emit the merge code.
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cgen()->frame()->MergeTo(entry_frame_);
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} else if (i == reaching_frames_.length() - 1 && had_fall_through) {
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// If this is the fall through frame, and it didn't need
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// merge code, we need to pick up the frame so we can jump
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// around subsequent merge blocks if necessary.
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cgen()->SetFrame(frame, &empty);
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reaching_frames_[i] = NULL;
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// The code generator may not have a current frame if there was no
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// fall through and none of the reaching frames needed merging.
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// In that case, clone the entry frame as the current frame.
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if (!cgen()->has_valid_frame()) {
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cgen()->SetFrame(new VirtualFrame(entry_frame_), &empty);
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// There may be unprocessed reaching frames that did not need
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// merge code. They will have unbound merge labels. Bind their
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// merge labels to be the same as the entry label and deallocate
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for (int i = 0; i < reaching_frames_.length(); i++) {
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if (!merge_labels_[i].is_bound()) {
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reaching_frames_[i] = NULL;
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__ bind(&merge_labels_[i]);
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// There are non-NULL reaching frames with bound labels for each
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// merge block, but only on backward targets.
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// There were no forward jumps. There must be a current frame and
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// this must be a bidirectional target.
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ASSERT(reaching_frames_.length() == 1);
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ASSERT(reaching_frames_[0] != NULL);
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ASSERT(direction_ == BIDIRECTIONAL);
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// Use a copy of the reaching frame so the original can be saved
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// for possible reuse as a backward merge block.
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cgen()->SetFrame(new VirtualFrame(reaching_frames_[0]), &empty);
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__ bind(&merge_labels_[0]);
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cgen()->frame()->MergeTo(entry_frame_);
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__ bind(&entry_label_);
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void BreakTarget::Jump() {
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// Drop leftover statement state from the frame before merging, without
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ASSERT(cgen()->has_valid_frame());
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int count = cgen()->frame()->height() - expected_height_;
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cgen()->frame()->ForgetElements(count);
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void BreakTarget::Jump(Result* arg) {
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// Drop leftover statement state from the frame before merging, without
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ASSERT(cgen()->has_valid_frame());
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int count = cgen()->frame()->height() - expected_height_;
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cgen()->frame()->ForgetElements(count);
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cgen()->frame()->Push(arg);
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void BreakTarget::Bind() {
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// All the forward-reaching frames should have been adjusted at the
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// jumps to this target.
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for (int i = 0; i < reaching_frames_.length(); i++) {
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ASSERT(reaching_frames_[i] == NULL ||
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reaching_frames_[i]->height() == expected_height_);
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// Drop leftover statement state from the frame before merging, even on
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// the fall through. This is so we can bind the return target with state
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if (cgen()->has_valid_frame()) {
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int count = cgen()->frame()->height() - expected_height_;
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cgen()->frame()->ForgetElements(count);
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void BreakTarget::Bind(Result* arg) {
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// All the forward-reaching frames should have been adjusted at the
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// jumps to this target.
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for (int i = 0; i < reaching_frames_.length(); i++) {
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ASSERT(reaching_frames_[i] == NULL ||
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reaching_frames_[i]->height() == expected_height_ + 1);
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// Drop leftover statement state from the frame before merging, even on
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// the fall through. This is so we can bind the return target with state
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if (cgen()->has_valid_frame()) {
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int count = cgen()->frame()->height() - expected_height_;
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cgen()->frame()->ForgetElements(count);
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cgen()->frame()->Push(arg);
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*arg = cgen()->frame()->Pop();
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} } // namespace v8::internal
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#endif // V8_TARGET_ARCH_X64