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The old invalidation lattice was incorrect because changes to control flow could cause changes to the call graph, so we've decided to change the way passes invalidate analysis. In the new scheme, the lattice is replaced with a list of traits that passes preserve or invalidate. The current traits are Calls and Branches. Now, passes report which traits they preserve, which is the opposite of the previous implementation where passes needed to report what they invalidate. Node: I tried to limit the changes in this commit to mechanical changes to ease the review. I will cleanup some of the code in a following commit. Swift SVN r26449
118 lines
3.8 KiB
C++
118 lines
3.8 KiB
C++
//===--- PostOrderAnalysis.h - SIL POT and RPOT Analysis -------*- 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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#ifndef SWIFT_SILANALYSIS_POSTORDERANALYSIS_H
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#define SWIFT_SILANALYSIS_POSTORDERANALYSIS_H
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#include "swift/SILAnalysis/Analysis.h"
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#include "swift/Basic/Range.h"
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#include "swift/SIL/CFG.h"
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#include "swift/SIL/SILBasicBlock.h"
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#include "swift/SIL/SILFunction.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/DenseMap.h"
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#include <vector>
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namespace swift {
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class SILBasicBlock;
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class SILFunction;
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/// This class is a simple wrapper around the POT iterator provided by LLVM. It
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/// lazily re-evaluates the post order when it is invalidated so that we do not
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/// reform the post order over and over again (it can be expensive).
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class PostOrderAnalysis : public SILAnalysis {
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struct FunctionPOTInfo {
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bool IsInvalidated;
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std::vector<SILBasicBlock *> PostOrder;
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FunctionPOTInfo() : IsInvalidated(true), PostOrder() {}
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FunctionPOTInfo(const FunctionPOTInfo &) = delete;
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FunctionPOTInfo &operator=(const FunctionPOTInfo &) = delete;
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FunctionPOTInfo(const FunctionPOTInfo &&F) {
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IsInvalidated = F.IsInvalidated;
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PostOrder = std::move(F.PostOrder);
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}
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FunctionPOTInfo &operator=(const FunctionPOTInfo &&F) {
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IsInvalidated = F.IsInvalidated;
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PostOrder = std::move(F.PostOrder);
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return *this;
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}
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void recompute(SILFunction *F) {
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assert(IsInvalidated && "Should only call this if the POT info is "
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"invalidated for this function.");
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PostOrder.clear();
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std::copy(po_begin(F), po_end(F), std::back_inserter(PostOrder));
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IsInvalidated = false;
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}
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};
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llvm::DenseMap<SILFunction *, FunctionPOTInfo> FunctionToPOTMap;
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public:
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PostOrderAnalysis(SILModule *) : SILAnalysis(AnalysisKind::PostOrder) {}
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// This is a cache and shouldn't be copied around.
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PostOrderAnalysis(const PostOrderAnalysis &) = delete;
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PostOrderAnalysis &operator=(const PostOrderAnalysis &) = delete;
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using iterator = std::vector<SILBasicBlock *>::iterator;
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using reverse_iterator = std::vector<SILBasicBlock *>::reverse_iterator;
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using range = Range<iterator>;
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using reverse_range = Range<reverse_iterator>;
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Range<iterator> getPostOrder(SILFunction *F) {
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FunctionPOTInfo &POTInfo = FunctionToPOTMap[F];
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if (POTInfo.IsInvalidated)
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POTInfo.recompute(F);
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return Range<iterator>(POTInfo.PostOrder.begin(), POTInfo.PostOrder.end());
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}
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Range<reverse_iterator> getReversePostOrder(SILFunction *F) {
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FunctionPOTInfo &POTInfo = FunctionToPOTMap[F];
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if (POTInfo.IsInvalidated)
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POTInfo.recompute(F);
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return reversed(POTInfo.PostOrder);
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}
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// Return the size of the post order for \p F.
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unsigned size(SILFunction *F) const {
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auto R = const_cast<PostOrderAnalysis *>(this)->getPostOrder(F);
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// This is cheap since we know that we are using vector iterators.
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return std::distance(R.begin(), R.end());
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}
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static bool classof(const SILAnalysis *S) {
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return S->getKind() == AnalysisKind::PostOrder;
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}
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virtual void invalidate(SILAnalysis::PreserveKind K) {
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if (!(K & PreserveKind::Branches)) {
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FunctionToPOTMap.clear();
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}
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}
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virtual void invalidate(SILFunction* F, SILAnalysis::PreserveKind K) {
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if (!(K & PreserveKind::Branches)) {
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// Invalidate just this one function. We will lazily recompute it.
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FunctionToPOTMap[F].IsInvalidated = true;
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}
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}
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};
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} // end namespace swift
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#endif
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