2009-02-27 13:00:32 +00:00
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// 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.h"
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2009-03-20 09:35:31 +00:00
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#include "virtual-frame.h"
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2009-02-27 13:00:32 +00:00
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namespace v8 { namespace internal {
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// -------------------------------------------------------------------------
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// Result implementation.
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Result::Result(Register reg, CodeGenerator* cgen)
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: type_(REGISTER),
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cgen_(cgen) {
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data_.reg_ = reg;
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ASSERT(reg.is_valid());
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cgen_->allocator()->Use(reg);
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}
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void Result::CopyTo(Result* destination) const {
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destination->type_ = type();
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destination->cgen_ = cgen_;
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if (is_register()) {
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destination->data_.reg_ = reg();
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cgen_->allocator()->Use(reg());
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} else if (is_constant()) {
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destination->data_.handle_ = data_.handle_;
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} else {
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ASSERT(!is_valid());
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}
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}
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void Result::Unuse() {
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if (is_register()) {
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cgen_->allocator()->Unuse(reg());
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}
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type_ = INVALID;
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}
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// -------------------------------------------------------------------------
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// RegisterFile implementation.
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void RegisterFile::CopyTo(RegisterFile* other) {
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for (int i = 0; i < kNumRegisters; i++) {
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other->ref_counts_[i] = ref_counts_[i];
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}
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}
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// -------------------------------------------------------------------------
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// RegisterAllocator implementation.
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Result RegisterAllocator::AllocateWithoutSpilling() {
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// Return the first free register, if any.
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2009-03-18 10:31:31 +00:00
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int free_reg = registers_.ScanForFreeRegister();
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if (free_reg < kNumRegisters) {
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Register free_result = { free_reg };
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return Result(free_result, cgen_);
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2009-02-27 13:00:32 +00:00
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}
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return Result(cgen_);
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}
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Result RegisterAllocator::Allocate() {
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Result result = AllocateWithoutSpilling();
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if (!result.is_valid()) {
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// Ask the current frame to spill a register.
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ASSERT(cgen_->has_valid_frame());
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Register free_reg = cgen_->frame()->SpillAnyRegister();
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if (free_reg.is_valid()) {
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ASSERT(!is_used(free_reg));
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return Result(free_reg, cgen_);
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}
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}
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return result;
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}
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Result RegisterAllocator::Allocate(Register target) {
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// If the target is not referenced, it can simply be allocated.
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if (!is_used(target)) {
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return Result(target, cgen_);
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}
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// If the target is only referenced in the frame, it can be spilled and
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// then allocated.
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ASSERT(cgen_->has_valid_frame());
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if (count(target) == cgen_->frame()->register_count(target)) {
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cgen_->frame()->Spill(target);
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ASSERT(!is_used(target));
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return Result(target, cgen_);
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}
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// Otherwise (if it's referenced outside the frame) we cannot allocate it.
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return Result(cgen_);
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}
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} } // namespace v8::internal
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