FunctionPropertiesAnalysis.h

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//=- FunctionPropertiesAnalysis.h - Function Properties Analysis --*- 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 the FunctionPropertiesInfo and FunctionPropertiesAnalysis
// classes used to extract function properties.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_ANALYSIS_FUNCTIONPROPERTIESANALYSIS_H
#define LLVM_ANALYSIS_FUNCTIONPROPERTIESANALYSIS_H
 
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/PassManager.h"
 
namespace llvm {
class DominatorTree;
class Function;
class LoopInfo;
 
class FunctionPropertiesInfo {
  friend class FunctionPropertiesUpdater;
  void updateForBB(const BasicBlock &BB, int64_t Direction);
  void updateAggregateStats(const Function &F, const LoopInfo &LI);
  void reIncludeBB(const BasicBlock &BB);
 
public:
  static FunctionPropertiesInfo
  getFunctionPropertiesInfo(const Function &F, FunctionAnalysisManager &FAM);
 
  bool operator==(const FunctionPropertiesInfo &FPI) const {
    return std::memcmp(this, &FPI, sizeof(FunctionPropertiesInfo)) == 0;
  }
 
  bool operator!=(const FunctionPropertiesInfo &FPI) const {
    return !(*this == FPI);
  }
 
  void print(raw_ostream &OS) const;
 
  /// Number of basic blocks
  int64_t BasicBlockCount = 0;
 
  /// Number of blocks reached from a conditional instruction, or that are
  /// 'cases' of a SwitchInstr.
  // FIXME: We may want to replace this with a more meaningful metric, like
  // number of conditionally executed blocks:
  // 'if (a) s();' would be counted here as 2 blocks, just like
  // 'if (a) s(); else s2(); s3();' would.
  int64_t BlocksReachedFromConditionalInstruction = 0;
 
  /// Number of uses of this function, plus 1 if the function is callable
  /// outside the module.
  int64_t Uses = 0;
 
  /// Number of direct calls made from this function to other functions
  /// defined in this module.
  int64_t DirectCallsToDefinedFunctions = 0;
 
  // Load Instruction Count
  int64_t LoadInstCount = 0;
 
  // Store Instruction Count
  int64_t StoreInstCount = 0;
 
  // Maximum Loop Depth in the Function
  int64_t MaxLoopDepth = 0;
 
  // Number of Top Level Loops in the Function
  int64_t TopLevelLoopCount = 0;
 
  // All non-debug instructions
  int64_t TotalInstructionCount = 0;
};
 
// Analysis pass
class FunctionPropertiesAnalysis
    : public AnalysisInfoMixin<FunctionPropertiesAnalysis> {
 
public:
  static AnalysisKey Key;
 
  using Result = const FunctionPropertiesInfo;
 
  FunctionPropertiesInfo run(Function &F, FunctionAnalysisManager &FAM);
};
 
/// Printer pass for the FunctionPropertiesAnalysis results.
class FunctionPropertiesPrinterPass
    : public PassInfoMixin<FunctionPropertiesPrinterPass> {
  raw_ostream &OS;
 
public:
  explicit FunctionPropertiesPrinterPass(raw_ostream &OS) : OS(OS) {}
 
  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
 
/// Correctly update FunctionPropertiesInfo post-inlining. A
/// FunctionPropertiesUpdater keeps the state necessary for tracking the changes
/// llvm::InlineFunction makes. The idea is that inlining will at most modify
/// a few BBs of the Caller (maybe the entry BB and definitely the callsite BB)
/// and potentially affect exception handling BBs in the case of invoke
/// inlining.
class FunctionPropertiesUpdater {
public:
  FunctionPropertiesUpdater(FunctionPropertiesInfo &FPI, const CallBase &CB);
 
  void finish(FunctionAnalysisManager &FAM) const;
 
private:
  FunctionPropertiesInfo &FPI;
  const BasicBlock &CallSiteBB;
  const Function &Caller;
 
  DenseSet<const BasicBlock *> Successors;
};
} // namespace llvm
#endif // LLVM_ANALYSIS_FUNCTIONPROPERTIESANALYSIS_H