ee53b0a5ed
BUG= R=titzer@chromium.org Review URL: https://chromiumcodereview.appspot.com/22555004 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16139 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
90 lines
3.3 KiB
C++
90 lines
3.3 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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#ifndef V8_HYDROGEN_GVN_H_
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#define V8_HYDROGEN_GVN_H_
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#include "hydrogen.h"
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#include "hydrogen-instructions.h"
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#include "compiler.h"
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#include "zone.h"
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namespace v8 {
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namespace internal {
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// Perform common subexpression elimination and loop-invariant code motion.
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class HGlobalValueNumberingPhase : public HPhase {
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public:
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explicit HGlobalValueNumberingPhase(HGraph* graph);
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void Run() {
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Analyze();
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// Trigger a second analysis pass to further eliminate duplicate values
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// that could only be discovered by removing side-effect-generating
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// instructions during the first pass.
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if (FLAG_smi_only_arrays && removed_side_effects_) {
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Analyze();
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// TODO(danno): Turn this into a fixpoint iteration.
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}
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}
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private:
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void Analyze();
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GVNFlagSet CollectSideEffectsOnPathsToDominatedBlock(
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HBasicBlock* dominator,
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HBasicBlock* dominated);
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void AnalyzeGraph();
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void ComputeBlockSideEffects();
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void LoopInvariantCodeMotion();
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void ProcessLoopBlock(HBasicBlock* block,
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HBasicBlock* before_loop,
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GVNFlagSet loop_kills,
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GVNFlagSet* accumulated_first_time_depends,
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GVNFlagSet* accumulated_first_time_changes);
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bool AllowCodeMotion();
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bool ShouldMove(HInstruction* instr, HBasicBlock* loop_header);
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bool removed_side_effects_;
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// A map of block IDs to their side effects.
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ZoneList<GVNFlagSet> block_side_effects_;
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// A map of loop header block IDs to their loop's side effects.
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ZoneList<GVNFlagSet> loop_side_effects_;
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// Used when collecting side effects on paths from dominator to
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// dominated.
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BitVector visited_on_paths_;
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DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase);
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};
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} } // namespace v8::internal
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#endif // V8_HYDROGEN_GVN_H_
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