f4735247cf
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1389 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
259 lines
9.5 KiB
C++
259 lines
9.5 KiB
C++
// Copyright 2008 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.h"
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#include "jump-target.h"
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namespace v8 { namespace internal {
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// -------------------------------------------------------------------------
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// JumpTarget implementation.
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#define __ masm_->
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void JumpTarget::Jump() {
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ASSERT(cgen_ != NULL);
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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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if (is_bound()) {
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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()->MergeTo(entry_frame_);
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cgen_->DeleteFrame();
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__ jmp(&entry_label_);
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} else {
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// Forward jump. The current frame is added to the end of the list
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// of frames reaching the target block and a jump to the merge code
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// is emitted.
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AddReachingFrame(cgen_->frame());
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RegisterFile empty;
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cgen_->SetFrame(NULL, &empty);
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__ jmp(&merge_labels_.last());
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}
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is_linked_ = !is_bound_;
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}
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void JumpTarget::Branch(Condition cc, Hint ignored) {
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ASSERT(cgen_ != NULL);
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ASSERT(cgen_->has_valid_frame());
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if (is_bound()) {
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// Backward branch. We have an expected frame to merge to on the
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// backward edge. We negate the condition and emit the merge code
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// here.
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//
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// TODO(210): we should try to avoid negating the condition in the
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// case where there is no merge code to emit. Otherwise, we emit
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// a branch around an unconditional jump.
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ASSERT(direction_ == BIDIRECTIONAL);
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Label original_fall_through;
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__ b(NegateCondition(cc), &original_fall_through);
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// Swap the current frame for a copy of it, saving non-frame
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// register reference counts and invalidating all non-frame register
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// references except the reserved ones on the backward edge.
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VirtualFrame* original_frame = cgen_->frame();
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VirtualFrame* working_frame = new VirtualFrame(original_frame);
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RegisterFile non_frame_registers = RegisterAllocator::Reserved();
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cgen_->SetFrame(working_frame, &non_frame_registers);
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working_frame->MergeTo(entry_frame_);
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cgen_->DeleteFrame();
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__ jmp(&entry_label_);
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// Restore the frame and its associated non-frame registers.
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cgen_->SetFrame(original_frame, &non_frame_registers);
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__ bind(&original_fall_through);
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} else {
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// Forward branch. A copy of the current frame is added to the end
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// of the list of frames reaching the target block and a branch to
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// the merge code is emitted.
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AddReachingFrame(new VirtualFrame(cgen_->frame()));
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__ b(cc, &merge_labels_.last());
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}
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is_linked_ = !is_bound_;
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}
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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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AddReachingFrame(target_frame);
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__ bl(&merge_labels_.last());
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is_linked_ = !is_bound_;
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}
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void JumpTarget::Bind(int mergable_elements) {
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ASSERT(cgen_ != NULL);
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ASSERT(!is_bound());
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// Live non-frame registers are not allowed at the start of a basic
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// block.
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ASSERT(!cgen_->has_valid_frame() || cgen_->HasValidEntryRegisters());
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// Compute the frame to use for entry to the block.
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ComputeEntryFrame(mergable_elements);
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if (is_linked()) {
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// There were forward jumps. Handle merging the reaching frames
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// and possible fall through to the entry frame.
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// Some moves required to merge to an expected frame require
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// purely frame state changes, and do not require any code
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// generation. Perform those first to increase the possibility of
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// finding equal frames below.
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if (cgen_->has_valid_frame()) {
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cgen_->frame()->PrepareMergeTo(entry_frame_);
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}
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for (int i = 0; i < reaching_frames_.length(); i++) {
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reaching_frames_[i]->PrepareMergeTo(entry_frame_);
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}
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// If there is a fall through to the jump target and it needs
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// merge code, process it first.
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if (cgen_->has_valid_frame() && !cgen_->frame()->Equals(entry_frame_)) {
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// Loop over all the reaching frames, looking for any that can
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// share merge code with this one.
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for (int i = 0; i < reaching_frames_.length(); i++) {
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if (cgen_->frame()->Equals(reaching_frames_[i])) {
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// Set the reaching frames element to null to avoid
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// processing it later, and then bind its entry label.
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delete reaching_frames_[i];
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reaching_frames_[i] = NULL;
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__ bind(&merge_labels_[i]);
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}
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}
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// Emit the merge code.
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cgen_->frame()->MergeTo(entry_frame_);
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}
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// Loop over the (non-null) reaching frames and process any that
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// need merge code.
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for (int i = 0; i < reaching_frames_.length(); i++) {
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VirtualFrame* frame = reaching_frames_[i];
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if (frame != NULL && !frame->Equals(entry_frame_)) {
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// Set the reaching frames element to null to avoid processing
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// it later. Do not delete it as it is needed for merging.
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reaching_frames_[i] = NULL;
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// If the code generator has a current frame (a fall-through
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// or a previously merged frame), insert a jump around the
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// merge code we are about to generate.
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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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}
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// Set the frame to merge as the code generator's current
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// frame and bind its merge label.
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RegisterFile reserved_registers = RegisterAllocator::Reserved();
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cgen_->SetFrame(frame, &reserved_registers);
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__ bind(&merge_labels_[i]);
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// Loop over the remaining (non-null) reaching frames, looking
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// for any that can share merge code with this one.
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for (int j = i + 1; j < reaching_frames_.length(); j++) {
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VirtualFrame* other = reaching_frames_[j];
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if (other != NULL && frame->Equals(other)) {
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delete other;
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reaching_frames_[j] = NULL;
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__ bind(&merge_labels_[j]);
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}
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}
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// Emit the merge code.
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cgen_->frame()->MergeTo(entry_frame_);
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}
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}
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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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RegisterFile reserved_registers = RegisterAllocator::Reserved();
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cgen_->SetFrame(new VirtualFrame(entry_frame_), &reserved_registers);
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}
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// There is certainly a current frame equal to the entry frame.
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// Bind the entry frame label.
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__ bind(&entry_label_);
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// There may be unprocessed reaching frames that did not need
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// merge code. Bind their merge labels to be the same as the
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// entry label.
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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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delete reaching_frames_[i];
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__ bind(&merge_labels_[i]);
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}
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}
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// All the reaching frames except the one that is the current
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// frame (if it is one of the reaching frames) have been deleted.
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reaching_frames_.Clear();
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merge_labels_.Clear();
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} else {
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// There were no forward jumps. The current frame is merged to
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// the entry frame.
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cgen_->frame()->MergeTo(entry_frame_);
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__ bind(&entry_label_);
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}
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is_linked_ = false;
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is_bound_ = true;
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}
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#undef __
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} } // namespace v8::internal
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