c9b41c6995
LOG=Y BUG=chromium:319835,chromium:319860 R=dslomov@chromium.org Review URL: https://codereview.chromium.org/74113002 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17801 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
81 lines
3.4 KiB
C++
81 lines
3.4 KiB
C++
// Copyright 2013 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 "hydrogen-dehoist.h"
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namespace v8 {
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namespace internal {
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static void DehoistArrayIndex(ArrayInstructionInterface* array_operation) {
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HValue* index = array_operation->GetKey()->ActualValue();
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if (!index->representation().IsSmiOrInteger32()) return;
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if (!index->IsAdd() && !index->IsSub()) return;
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HConstant* constant;
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HValue* subexpression;
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HBinaryOperation* binary_operation = HBinaryOperation::cast(index);
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if (binary_operation->left()->IsConstant() && index->IsAdd()) {
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subexpression = binary_operation->right();
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constant = HConstant::cast(binary_operation->left());
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} else if (binary_operation->right()->IsConstant()) {
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subexpression = binary_operation->left();
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constant = HConstant::cast(binary_operation->right());
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} else {
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return;
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}
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if (!constant->HasInteger32Value()) return;
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int32_t sign = binary_operation->IsSub() ? -1 : 1;
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int32_t value = constant->Integer32Value() * sign;
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// We limit offset values to 30 bits because we want to avoid the risk of
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// overflows when the offset is added to the object header size.
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if (value >= 1 << array_operation->MaxIndexOffsetBits() || value < 0) return;
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array_operation->SetKey(subexpression);
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if (binary_operation->HasNoUses()) {
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binary_operation->DeleteAndReplaceWith(NULL);
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}
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array_operation->SetIndexOffset(static_cast<uint32_t>(value));
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array_operation->SetDehoisted(true);
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}
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void HDehoistIndexComputationsPhase::Run() {
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const ZoneList<HBasicBlock*>* blocks(graph()->blocks());
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for (int i = 0; i < blocks->length(); ++i) {
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for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) {
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HInstruction* instr = it.Current();
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if (instr->IsLoadKeyed()) {
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DehoistArrayIndex(HLoadKeyed::cast(instr));
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} else if (instr->IsStoreKeyed()) {
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DehoistArrayIndex(HStoreKeyed::cast(instr));
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}
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}
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}
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}
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} } // namespace v8::internal
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