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04d9f968fd
This is important since to be more aggressive we are ignoring incoming values that are no-payload enums since as far as we are concerned they do not matter since retains, releases on those values are no-ops. Swift SVN r21932
76 lines
2.5 KiB
C++
76 lines
2.5 KiB
C++
//===--- RCIdentityAnalysis.h ------------------------------*- C++ -*------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This is an analysis that determines the ref count identity (i.e. gc root) of
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// a pointer. Any values with the same ref count identity are able to be
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// retained and released interchangably.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SILANALYSIS_RCIDENTITYANALYSIS_H
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#define SWIFT_SILANALYSIS_RCIDENTITYANALYSIS_H
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#include "swift/SIL/SILValue.h"
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#include "swift/SIL/SILArgument.h"
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#include "swift/SILAnalysis/Analysis.h"
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#include "swift/SILAnalysis/DominanceAnalysis.h"
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#include "swift/SILPasses/PassManager.h"
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namespace swift {
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class DominanceAnalysis;
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/// This class is a simple wrapper around an identity cache.
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class RCIdentityAnalysis : public SILAnalysis {
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llvm::DenseMap<SILValue, SILValue> Cache;
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llvm::DenseSet<SILArgument *> VisitedArgs;
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DominanceAnalysis *DA;
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/// This number is arbitrary and conservative. At some point if compile time
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/// is not an issue, this value should be made more aggressive (i.e. greater).
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enum { MaxRecursionDepth = 16 };
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public:
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RCIdentityAnalysis(SILModule *, SILPassManager *PM)
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: SILAnalysis(AnalysisKind::RCIdentity), Cache(), VisitedArgs(),
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DA(PM->getAnalysis<DominanceAnalysis>()) {}
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RCIdentityAnalysis(const RCIdentityAnalysis &) = delete;
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RCIdentityAnalysis &operator=(const RCIdentityAnalysis &) = delete;
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SILValue getRCIdentityRoot(SILValue V);
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static bool classof(const SILAnalysis *S) {
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return S->getKind() == AnalysisKind::RCIdentity;
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}
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virtual void invalidate(InvalidationKind K) {
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if (K >= InvalidationKind::Instructions) {
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Cache.clear();
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}
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}
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// TODO: Add function specific cache to save compile time.
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virtual void invalidate(SILFunction* F, InvalidationKind K) {
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invalidate(K);
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}
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private:
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SILValue getRCIdentityRootInner(SILValue V, unsigned RecursionDepth);
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SILValue stripRCIdentityPreservingOps(SILValue V, unsigned RecursionDepth);
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SILValue stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth);
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};
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} // end swift namespace
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#endif
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