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// Copyright 2009 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "codegen-inl.h"
#include "register-allocator-inl.h"
#include "virtual-frame-inl.h"
namespace v8 {
namespace internal {
// -------------------------------------------------------------------------
// Result implementation.
Result::Result(Register reg, TypeInfo info) {
ASSERT(reg.is_valid() && !RegisterAllocator::IsReserved(reg));
CodeGeneratorScope::Current(Isolate::Current())->allocator()->Use(reg);
value_ = TypeField::encode(REGISTER)
| TypeInfoField::encode(info.ToInt())
| DataField::encode(reg.code_);
}
// -------------------------------------------------------------------------
// RegisterAllocator implementation.
Result RegisterAllocator::AllocateWithoutSpilling() {
// Return the first free register, if any.
int num = registers_.ScanForFreeRegister();
if (num == RegisterAllocator::kInvalidRegister) {
return Result();
}
return Result(RegisterAllocator::ToRegister(num));
}
Result RegisterAllocator::Allocate() {
Result result = AllocateWithoutSpilling();
if (!result.is_valid()) {
// Ask the current frame to spill a register.
ASSERT(cgen_->has_valid_frame());
Register free_reg = cgen_->frame()->SpillAnyRegister();
if (free_reg.is_valid()) {
ASSERT(!is_used(free_reg));
return Result(free_reg);
}
}
return result;
}
Result RegisterAllocator::Allocate(Register target) {
// If the target is not referenced, it can simply be allocated.
if (!is_used(RegisterAllocator::ToNumber(target))) {
return Result(target);
}
// If the target is only referenced in the frame, it can be spilled and
// then allocated.
ASSERT(cgen_->has_valid_frame());
if (cgen_->frame()->is_used(RegisterAllocator::ToNumber(target)) &&
count(target) == 1) {
cgen_->frame()->Spill(target);
ASSERT(!is_used(RegisterAllocator::ToNumber(target)));
return Result(target);
}
// Otherwise (if it's referenced outside the frame) we cannot allocate it.
return Result();
}
} } // namespace v8::internal
|
