FunctionSummary.h

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//===- FunctionSummary.h - Stores summaries of functions. -------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines a summary of a function gathered/used by static analysis.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_FUNCTIONSUMMARY_H
#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_FUNCTIONSUMMARY_H
 
#include "clang/AST/Decl.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallBitVector.h"
#include <cassert>
#include <deque>
#include <optional>
#include <utility>
 
namespace clang {
namespace ento {
 
using SetOfDecls = std::deque<Decl *>;
using SetOfConstDecls = llvm::DenseSet<const Decl *>;
 
class FunctionSummariesTy {
  class FunctionSummary {
  public:
    /// Marks the IDs of the basic blocks visited during the analyzes.
    llvm::SmallBitVector VisitedBasicBlocks;
 
    /// Total number of blocks in the function.
    unsigned TotalBasicBlocks : 30;
 
    /// True if this function has been checked against the rules for which
    /// functions may be inlined.
    unsigned InlineChecked : 1;
 
    /// True if this function may be inlined.
    unsigned MayInline : 1;
 
    /// The number of times the function has been inlined.
    unsigned TimesInlined : 32;
 
    FunctionSummary()
        : TotalBasicBlocks(0), InlineChecked(0), MayInline(0),
          TimesInlined(0) {}
  };
 
  using MapTy = llvm::DenseMap<const Decl *, FunctionSummary>;
  MapTy Map;
 
public:
  MapTy::iterator findOrInsertSummary(const Decl *D) {
    MapTy::iterator I = Map.find(D);
    if (I != Map.end())
      return I;
 
    using KVPair = std::pair<const Decl *, FunctionSummary>;
 
    I = Map.insert(KVPair(D, FunctionSummary())).first;
    assert(I != Map.end());
    return I;
  }
 
  void markMayInline(const Decl *D) {
    MapTy::iterator I = findOrInsertSummary(D);
    I->second.InlineChecked = 1;
    I->second.MayInline = 1;
  }
 
  void markShouldNotInline(const Decl *D) {
    MapTy::iterator I = findOrInsertSummary(D);
    I->second.InlineChecked = 1;
    I->second.MayInline = 0;
  }
 
  void markReachedMaxBlockCount(const Decl *D) {
    markShouldNotInline(D);
  }
 
  std::optional<bool> mayInline(const Decl *D) {
    MapTy::const_iterator I = Map.find(D);
    if (I != Map.end() && I->second.InlineChecked)
      return I->second.MayInline;
    return std::nullopt;
  }
 
  void markVisitedBasicBlock(unsigned ID, const Decl* D, unsigned TotalIDs) {
    MapTy::iterator I = findOrInsertSummary(D);
    llvm::SmallBitVector &Blocks = I->second.VisitedBasicBlocks;
    assert(ID < TotalIDs);
    if (TotalIDs > Blocks.size()) {
      Blocks.resize(TotalIDs);
      I->second.TotalBasicBlocks = TotalIDs;
    }
    Blocks.set(ID);
  }
 
  unsigned getNumVisitedBasicBlocks(const Decl* D) {
    MapTy::const_iterator I = Map.find(D);
    if (I != Map.end())
      return I->second.VisitedBasicBlocks.count();
    return 0;
  }
 
  unsigned getNumTimesInlined(const Decl* D) {
    MapTy::const_iterator I = Map.find(D);
    if (I != Map.end())
      return I->second.TimesInlined;
    return 0;
  }
 
  void bumpNumTimesInlined(const Decl* D) {
    MapTy::iterator I = findOrInsertSummary(D);
    I->second.TimesInlined++;
  }
 
  /// Get the percentage of the reachable blocks.
  unsigned getPercentBlocksReachable(const Decl *D) {
    MapTy::const_iterator I = Map.find(D);
      if (I != Map.end())
        return ((I->second.VisitedBasicBlocks.count() * 100) /
                 I->second.TotalBasicBlocks);
    return 0;
  }
 
  unsigned getTotalNumBasicBlocks();
  unsigned getTotalNumVisitedBasicBlocks();
};
 
} // namespace ento
} // namespace clang
 
#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_FUNCTIONSUMMARY_H