include/llvm/IR/OptBisect.h

   1 //===- llvm/IR/OptBisect.h - LLVM Bisect support ----------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// This file declares the interface for bisecting optimizations.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_IR_OPTBISECT_H
  15 #define LLVM_IR_OPTBISECT_H
  16
  17 #include "llvm/ADT/StringRef.h"
  18
  19 namespace llvm {
  20
  21 class Pass;
  22 class Module;
  23 class Function;
  24 class BasicBlock;
  25 class Region;
  26 class Loop;
  27 class CallGraphSCC;
  28
  29 /// Extensions to this class implement mechanisms to disable passes and
  30 /// individual optimizations at compile time.
  31 class OptPassGate {
  32 public:
  33   virtual ~OptPassGate() = default;
  34
  35   virtual bool shouldRunPass(const Pass *P, const Module &U) { return true; }
  36   virtual bool shouldRunPass(const Pass *P, const Function &U)  {return true; }
  37   virtual bool shouldRunPass(const Pass *P, const BasicBlock &U)  { return true; }
  38   virtual bool shouldRunPass(const Pass *P, const Region &U)  { return true; }
  39   virtual bool shouldRunPass(const Pass *P, const Loop &U)  { return true; }
  40   virtual bool shouldRunPass(const Pass *P, const CallGraphSCC &U)  { return true; }
  41 };
  42
  43 /// This class implements a mechanism to disable passes and individual
  44 /// optimizations at compile time based on a command line option
  45 /// (-opt-bisect-limit) in order to perform a bisecting search for
  46 /// optimization-related problems.
  47 class OptBisect : public OptPassGate {
  48 public:
  49   /// Default constructor, initializes the OptBisect state based on the
  50   /// -opt-bisect-limit command line argument.
  51   ///
  52   /// By default, bisection is disabled.
  53   ///
  54   /// Clients should not instantiate this class directly.  All access should go
  55   /// through LLVMContext.
  56   OptBisect();
  57
  58   virtual ~OptBisect() = default;
  59
  60   /// Checks the bisect limit to determine if the specified pass should run.
  61   ///
  62   /// These functions immediately return true if bisection is disabled. If the
  63   /// bisect limit is set to -1, the functions print a message describing
  64   /// the pass and the bisect number assigned to it and return true.  Otherwise,
  65   /// the functions print a message with the bisect number assigned to the
  66   /// pass and indicating whether or not the pass will be run and return true if
  67   /// the bisect limit has not yet been exceeded or false if it has.
  68   ///
  69   /// Most passes should not call these routines directly. Instead, they are
  70   /// called through helper routines provided by the pass base classes.  For
  71   /// instance, function passes should call FunctionPass::skipFunction().
  72   bool shouldRunPass(const Pass *P, const Module &U) override;
  73   bool shouldRunPass(const Pass *P, const Function &U) override;
  74   bool shouldRunPass(const Pass *P, const BasicBlock &U) override;
  75   bool shouldRunPass(const Pass *P, const Region &U) override;
  76   bool shouldRunPass(const Pass *P, const Loop &U) override;
  77   bool shouldRunPass(const Pass *P, const CallGraphSCC &U) override;
  78
  79 private:
  80   bool checkPass(const StringRef PassName, const StringRef TargetDesc);
  81
  82   bool BisectEnabled = false;
  83   unsigned LastBisectNum = 0;
  84 };
  85
  86 } // end namespace llvm
  87
  88 #endif // LLVM_IR_OPTBISECT_H