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104 lines
3.6 KiB
104 lines
3.6 KiB
// 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 "virtual-frame-inl.h"
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namespace v8 {
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namespace internal {
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// -------------------------------------------------------------------------
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// Result implementation.
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Result::Result(Register reg, TypeInfo info) {
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ASSERT(reg.is_valid() && !RegisterAllocator::IsReserved(reg));
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CodeGeneratorScope::Current()->allocator()->Use(reg);
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value_ = TypeField::encode(REGISTER)
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| TypeInfoField::encode(info.ToInt())
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| DataField::encode(reg.code_);
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}
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Result::ZoneObjectList* Result::ConstantList() {
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static ZoneObjectList list(10);
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return &list;
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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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int num = registers_.ScanForFreeRegister();
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if (num == RegisterAllocator::kInvalidRegister) {
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return Result();
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}
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return Result(RegisterAllocator::ToRegister(num));
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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);
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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(RegisterAllocator::ToNumber(target))) {
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return Result(target);
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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 (cgen_->frame()->is_used(RegisterAllocator::ToNumber(target)) &&
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count(target) == 1) {
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cgen_->frame()->Spill(target);
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ASSERT(!is_used(RegisterAllocator::ToNumber(target)));
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return Result(target);
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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();
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}
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} } // namespace v8::internal
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