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#include <limits>
19
20namespace llvm {
21
22/// Extensions to this class implement mechanisms to disable passes and
23/// individual optimizations at compile time.
24class OptPassGate {
25public:
26 virtual ~OptPassGate() = default;
27
28 /// IRDescription is a textual description of the IR unit the pass is running
29 /// over.
30 virtual bool shouldRunPass(const StringRef PassName,
31 StringRef IRDescription) {
32 return true;
33 }
34
35 /// isEnabled() should return true before calling shouldRunPass().
36 virtual bool isEnabled() const { return false; }
37};
38
39/// This class implements a mechanism to disable passes and individual
40/// optimizations at compile time based on a command line option
41/// (-opt-bisect-limit) in order to perform a bisecting search for
42/// optimization-related problems.
43class OptBisect : public OptPassGate {
44public:
45 /// Default constructor. Initializes the state to "disabled". The bisection
46 /// will be enabled by the cl::opt call-back when the command line option
47 /// is processed.
48 /// Clients should not instantiate this class directly. All access should go
49 /// through LLVMContext.
50 OptBisect() = default;
51
52 virtual ~OptBisect() = default;
53
54 /// Checks the bisect limit to determine if the specified pass should run.
55 ///
56 /// The method prints the name of the pass, its assigned bisect number, and
57 /// whether or not the pass will be executed. It returns true if the pass
58 /// should run, i.e. if the bisect limit is set to -1 or has not yet been
59 /// exceeded.
60 ///
61 /// Most passes should not call this routine directly. Instead, it is called
62 /// through helper routines provided by the base classes of the pass. For
63 /// instance, function passes should call FunctionPass::skipFunction().
64 bool shouldRunPass(const StringRef PassName,
65 StringRef IRDescription) override;
66
67 /// isEnabled() should return true before calling shouldRunPass().
68 bool isEnabled() const override { return BisectLimit != Disabled; }
69
70 /// Set the new optimization limit and reset the counter. Passing
71 /// OptBisect::Disabled disables the limiting.
72 void setLimit(int Limit) {
73 BisectLimit = Limit;
74 LastBisectNum = 0;
75 }
76
77 static const int Disabled = std::numeric_limits<int>::max();
78
79private:
80 int BisectLimit = Disabled;
81 int LastBisectNum = 0;
82};
83
84/// Singleton instance of the OptBisect class, so multiple pass managers don't
85/// need to coordinate their uses of OptBisect.
86OptPassGate &getGlobalPassGate();
87
88} // end namespace llvm
89
90#endif // LLVM_IR_OPTBISECT_H
91

source code of llvm/include/llvm/IR/OptBisect.h