Coverage Report

Created: 2020-09-19 12:23

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Analysis/Analyses/LiveVariables.h
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//===- LiveVariables.h - Live Variable Analysis for Source CFGs -*- 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 implements Live Variables analysis for source-level CFGs.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_LIVEVARIABLES_H
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#define LLVM_CLANG_ANALYSIS_ANALYSES_LIVEVARIABLES_H
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#include "clang/AST/Decl.h"
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#include "clang/Analysis/AnalysisDeclContext.h"
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#include "llvm/ADT/ImmutableSet.h"
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namespace clang {
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class CFG;
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class CFGBlock;
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class Stmt;
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class DeclRefExpr;
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class SourceManager;
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class LiveVariables : public ManagedAnalysis {
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public:
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  class LivenessValues {
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  public:
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    llvm::ImmutableSet<const Expr *> liveExprs;
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    llvm::ImmutableSet<const VarDecl *> liveDecls;
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    llvm::ImmutableSet<const BindingDecl *> liveBindings;
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    bool equals(const LivenessValues &V) const;
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    LivenessValues()
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      : liveExprs(nullptr), liveDecls(nullptr), liveBindings(nullptr) {}
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    LivenessValues(llvm::ImmutableSet<const Expr *> liveExprs,
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                   llvm::ImmutableSet<const VarDecl *> LiveDecls,
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                   llvm::ImmutableSet<const BindingDecl *> LiveBindings)
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        : liveExprs(liveExprs), liveDecls(LiveDecls),
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          liveBindings(LiveBindings) {}
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    bool isLive(const Expr *E) const;
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    bool isLive(const VarDecl *D) const;
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    friend class LiveVariables;
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  };
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  class Observer {
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    virtual void anchor();
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  public:
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    virtual ~Observer() {}
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    /// A callback invoked right before invoking the
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    ///  liveness transfer function on the given statement.
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    virtual void observeStmt(const Stmt *S,
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                             const CFGBlock *currentBlock,
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                             const LivenessValues& V) {}
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    /// Called when the live variables analysis registers
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    /// that a variable is killed.
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    virtual void observerKill(const DeclRefExpr *DR) {}
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  };
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  ~LiveVariables() override;
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  /// Compute the liveness information for a given CFG.
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  static std::unique_ptr<LiveVariables>
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  computeLiveness(AnalysisDeclContext &analysisContext, bool killAtAssign);
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  /// Return true if a variable is live at the end of a
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  /// specified block.
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  bool isLive(const CFGBlock *B, const VarDecl *D);
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  /// Returns true if a variable is live at the beginning of the
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  ///  the statement.  This query only works if liveness information
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  ///  has been recorded at the statement level (see runOnAllBlocks), and
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  ///  only returns liveness information for block-level expressions.
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  bool isLive(const Stmt *S, const VarDecl *D);
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  /// Returns true the block-level expression value is live
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  ///  before the given block-level expression (see runOnAllBlocks).
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  bool isLive(const Stmt *Loc, const Expr *Val);
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  /// Print to stderr the variable liveness information associated with
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  /// each basic block.
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  void dumpBlockLiveness(const SourceManager &M);
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  /// Print to stderr the expression liveness information associated with
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  /// each basic block.
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  void dumpExprLiveness(const SourceManager &M);
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  void runOnAllBlocks(Observer &obs);
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  static std::unique_ptr<LiveVariables>
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  create(AnalysisDeclContext &analysisContext) {
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    return computeLiveness(analysisContext, true);
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  }
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  static const void *getTag();
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private:
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  LiveVariables(void *impl);
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  void *impl;
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};
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class RelaxedLiveVariables : public LiveVariables {
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public:
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  static std::unique_ptr<LiveVariables>
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  create(AnalysisDeclContext &analysisContext) {
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    return computeLiveness(analysisContext, false);
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  }
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  static const void *getTag();
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};
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} // end namespace clang
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#endif