| //===- 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/Support/ManagedStatic.h" |
| #include <limits> |
| |
| namespace llvm { |
| |
| class Pass; |
| |
| /// 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(const Pass *P, StringRef IRDescription) { |
| 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 a command line option |
| /// (-opt-bisect-limit) in order to perform a bisecting search for |
| /// optimization-related problems. |
| class 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; |
| |
| virtual ~OptBisect() = default; |
| |
| /// Checks the bisect limit to determine if the specified pass should run. |
| /// |
| /// This forwards to checkPass(). |
| bool shouldRunPass(const Pass *P, StringRef IRDescription) override; |
| |
| /// isEnabled() should return true before calling shouldRunPass(). |
| bool isEnabled() const override { return BisectLimit != Disabled; } |
| |
| /// Set the new optimization limit and reset the counter. Passing |
| /// OptBisect::Disabled disables the limiting. |
| void setLimit(int Limit) { |
| BisectLimit = Limit; |
| LastBisectNum = 0; |
| } |
| |
| /// Checks the bisect limit to determine if the specified pass should run. |
| /// |
| /// If the bisect limit is set to -1, the function prints a message describing |
| /// the pass and the bisect number assigned to it and return true. Otherwise, |
| /// the function prints a message with the bisect number assigned to the |
| /// pass and indicating whether or not the pass will be run and return true if |
| /// the bisect limit has not yet been exceeded or false if it has. |
| /// |
| /// Most passes should not call this routine directly. Instead, they are |
| /// called through helper routines provided by the pass base classes. For |
| /// instance, function passes should call FunctionPass::skipFunction(). |
| bool checkPass(const StringRef PassName, const StringRef TargetDesc); |
| |
| static const int Disabled = std::numeric_limits<int>::max(); |
| |
| private: |
| int BisectLimit = Disabled; |
| int LastBisectNum = 0; |
| }; |
| |
| /// Singleton instance of the OptBisect class, so multiple pass managers don't |
| /// need to coordinate their uses of OptBisect. |
| extern ManagedStatic<OptBisect> OptBisector; |
| } // end namespace llvm |
| |
| #endif // LLVM_IR_OPTBISECT_H |