OptBisect.h

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//===- llvm/IR/OptBisect.h - LLVM Bisect support ----------------*- 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file declares the interface for bisecting optimizations.
///
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_IR_OPTBISECT_H
#define LLVM_IR_OPTBISECT_H
 
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/IntegerInclusiveInterval.h"
 
namespace llvm {
 
/// Extensions to this class implement mechanisms to disable passes and
/// individual optimizations at compile time.
class OptPassGate {
public:
  virtual ~OptPassGate() = default;
 
  /// IRDescription is a textual description of the IR unit the pass is running
  /// over.
  virtual bool shouldRunPass(StringRef PassName,
                             StringRef IRDescription) const {
    return true;
  }
 
  /// isEnabled() should return true before calling shouldRunPass().
  virtual bool isEnabled() const { return false; }
};
 
/// This class implements a mechanism to disable passes and individual
/// optimizations at compile time based on two command line options
/// (-opt-bisect and -opt-disable) in order to perform a bisecting
/// search for optimization-related problems, and/or disable individual
/// passes or combinations thereof.
class LLVM_ABI OptBisect : public OptPassGate {
public:
  /// Default constructor. Initializes the state to "disabled". The bisection
  /// will be enabled by the cl::opt call-back when the command line option
  /// is processed.
  /// Clients should not instantiate this class directly.  All access should go
  /// through LLVMContext.
  OptBisect() = default;
 
  ~OptBisect() override = default;
 
  /// Checks the bisect intervals to determine if the specified pass should run.
  ///
  /// The method prints the name of the pass, its assigned bisect number, and
  /// whether or not the pass will be executed. It returns true if the pass
  /// should run, i.e. if no intervals are specified or the current pass number
  /// falls within one of the specified intervals.
  ///
  /// Most passes should not call this routine directly. Instead, it is called
  /// through helper routines provided by the base classes of the pass. For
  /// instance, function passes should call FunctionPass::skipFunction().
  bool shouldRunPass(StringRef PassName,
                     StringRef IRDescription) const override;
 
  /// isEnabled() should return true before calling shouldRunPass().
  bool isEnabled() const override {
    return !BisectIntervals.empty() || !DisabledPasses.empty();
  }
 
  /// Set intervals directly from an IntervalList.
  void setIntervals(IntegerInclusiveIntervalUtils::IntervalList Intervals) {
    BisectIntervals = std::move(Intervals);
  }
 
  /// Clear all intervals, effectively disabling bisection.
  void clearIntervals() {
    BisectIntervals.clear();
    LastBisectNum = 0;
  }
 
  /// Parses the command line argument to extract the names of the passes
  /// to be disabled. Multiple pass names can be provided with comma separation.
  void setDisabled(StringRef Pass) { DisabledPasses.insert(Pass); }
 
private:
  mutable int LastBisectNum = 0;
  IntegerInclusiveIntervalUtils::IntervalList BisectIntervals;
 
  StringSet<> DisabledPasses = {};
};
 
/// Singleton instance of the OptPassGate class, so multiple pass managers don't
/// need to coordinate their uses of OptBisect and OptDisable.
LLVM_ABI OptPassGate &getGlobalPassGate();
 
} // end namespace llvm
 
#endif // LLVM_IR_OPTBISECT_H