Coverage Report

Created: 2019-02-23 12:57

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Analysis/PhiValues.h
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//===- PhiValues.h - Phi Value Analysis -------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the PhiValues class, and associated passes, which can be
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// used to find the underlying values of the phis in a function, i.e. the
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// non-phi values that can be found by traversing the phi graph.
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//
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// This information is computed lazily and cached. If new phis are added to the
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// function they are handled correctly, but if an existing phi has its operands
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// modified PhiValues has to be notified by calling invalidateValue.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_PHIVALUES_H
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#define LLVM_ANALYSIS_PHIVALUES_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/IR/PassManager.h"
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#include "llvm/IR/ValueHandle.h"
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#include "llvm/Pass.h"
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namespace llvm {
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class Use;
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class Value;
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class PHINode;
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class Function;
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/// Class for calculating and caching the underlying values of phis in a
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/// function.
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///
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/// Initially the PhiValues is empty, and gets incrementally populated whenever
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/// it is queried.
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class PhiValues {
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public:
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  using ValueSet = SmallPtrSet<Value *, 4>;
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  /// Construct an empty PhiValues.
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1.39M
  PhiValues(const Function &F) : F(F) {}
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  /// Get the underlying values of a phi.
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  ///
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  /// This returns the cached value if PN has previously been processed,
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  /// otherwise it processes it first.
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  const ValueSet &getValuesForPhi(const PHINode *PN);
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  /// Notify PhiValues that the cached information using V is no longer valid
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  ///
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  /// Whenever a phi has its operands modified the cached values for that phi
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  /// (and the phis that use that phi) become invalid. A user of PhiValues has
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  /// to notify it of this by calling invalidateValue on either the operand or
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  /// the phi, which will then clear the relevant cached information.
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  void invalidateValue(const Value *V);
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  /// Free the memory used by this class.
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  void releaseMemory();
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  /// Print out the values currently in the cache.
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  void print(raw_ostream &OS) const;
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  /// Handle invalidation events in the new pass manager.
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  bool invalidate(Function &, const PreservedAnalyses &,
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                  FunctionAnalysisManager::Invalidator &);
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private:
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  using PhiSet = SmallPtrSet<const PHINode *, 4>;
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  using ConstValueSet = SmallPtrSet<const Value *, 4>;
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  /// The next depth number to be used by processPhi.
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  unsigned int NextDepthNumber = 1;
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  /// Depth numbers of phis. Phis with the same depth number are part of the
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  /// same strongly connected component.
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  DenseMap<const PHINode *, unsigned int> DepthMap;
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  /// Non-phi values reachable from each component.
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  DenseMap<unsigned int, ValueSet> NonPhiReachableMap;
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  /// All values reachable from each component.
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  DenseMap<unsigned int, ConstValueSet> ReachableMap;
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  /// A CallbackVH to notify PhiValues when a value is deleted or replaced, so
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  /// that the cached information for that value can be cleared to avoid
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  /// dangling pointers to invalid values.
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  class PhiValuesCallbackVH final : public CallbackVH {
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    PhiValues *PV;
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    void deleted() override;
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    void allUsesReplacedWith(Value *New) override;
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  public:
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    PhiValuesCallbackVH(Value *V, PhiValues *PV = nullptr)
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        : CallbackVH(V), PV(PV) {}
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  };
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  /// A set of callbacks to the values that processPhi has seen.
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  DenseSet<PhiValuesCallbackVH, DenseMapInfo<Value *>> TrackedValues;
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  /// The function that the PhiValues is for.
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  const Function &F;
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  /// Process a phi so that its entries in the depth and reachable maps are
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  /// fully populated.
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  void processPhi(const PHINode *PN, SmallVector<const PHINode *, 8> &Stack);
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};
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/// The analysis pass which yields a PhiValues
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///
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/// The analysis does nothing by itself, and just returns an empty PhiValues
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/// which will get filled in as it's used.
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class PhiValuesAnalysis : public AnalysisInfoMixin<PhiValuesAnalysis> {
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  friend AnalysisInfoMixin<PhiValuesAnalysis>;
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  static AnalysisKey Key;
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public:
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  using Result = PhiValues;
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  PhiValues run(Function &F, FunctionAnalysisManager &);
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};
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/// A pass for printing the PhiValues for a function.
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///
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/// This pass doesn't print whatever information the PhiValues happens to hold,
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/// but instead first uses the PhiValues to analyze all the phis in the function
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/// so the complete information is printed.
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class PhiValuesPrinterPass : public PassInfoMixin<PhiValuesPrinterPass> {
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  raw_ostream &OS;
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public:
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  explicit PhiValuesPrinterPass(raw_ostream &OS) : OS(OS) {}
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  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
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};
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/// Wrapper pass for the legacy pass manager
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class PhiValuesWrapperPass : public FunctionPass {
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  std::unique_ptr<PhiValues> Result;
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public:
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  static char ID;
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  PhiValuesWrapperPass();
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  PhiValues &getResult() { return *Result; }
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  const PhiValues &getResult() const { return *Result; }
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  bool runOnFunction(Function &F) override;
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  void releaseMemory() override;
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  void getAnalysisUsage(AnalysisUsage &AU) const override;
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};
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} // namespace llvm
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#endif