LLVM  12.0.0git
OptBisect.h
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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"
19 
20 namespace llvm {
21 
22 class Pass;
23 
24 /// Extensions to this class implement mechanisms to disable passes and
25 /// individual optimizations at compile time.
26 class OptPassGate {
27 public:
28  virtual ~OptPassGate() = default;
29 
30  /// IRDescription is a textual description of the IR unit the pass is running
31  /// over.
32  virtual bool shouldRunPass(const Pass *P, StringRef IRDescription) {
33  return true;
34  }
35 
36  /// isEnabled() should return true before calling shouldRunPass().
37  virtual bool isEnabled() const { return false; }
38 };
39 
40 /// This class implements a mechanism to disable passes and individual
41 /// optimizations at compile time based on a command line option
42 /// (-opt-bisect-limit) in order to perform a bisecting search for
43 /// optimization-related problems.
44 class OptBisect : public OptPassGate {
45 public:
46  /// Default constructor, initializes the OptBisect state based on the
47  /// -opt-bisect-limit command line argument.
48  ///
49  /// By default, bisection is disabled.
50  ///
51  /// Clients should not instantiate this class directly. All access should go
52  /// through LLVMContext.
53  OptBisect();
54 
55  virtual ~OptBisect() = default;
56 
57  /// Checks the bisect limit to determine if the specified pass should run.
58  ///
59  /// This forwards to checkPass().
60  bool shouldRunPass(const Pass *P, StringRef IRDescription) override;
61 
62  /// isEnabled() should return true before calling shouldRunPass().
63  bool isEnabled() const override { return BisectEnabled; }
64 
65  /// Checks the bisect limit to determine if the specified pass should run.
66  ///
67  /// If the bisect limit is set to -1, the function prints a message describing
68  /// the pass and the bisect number assigned to it and return true. Otherwise,
69  /// the function prints a message with the bisect number assigned to the
70  /// pass and indicating whether or not the pass will be run and return true if
71  /// the bisect limit has not yet been exceeded or false if it has.
72  ///
73  /// Most passes should not call this routine directly. Instead, they are
74  /// called through helper routines provided by the pass base classes. For
75  /// instance, function passes should call FunctionPass::skipFunction().
76  bool checkPass(const StringRef PassName, const StringRef TargetDesc);
77 
78 private:
79  bool BisectEnabled = false;
80  unsigned LastBisectNum = 0;
81 };
82 
83 /// Singleton instance of the OptBisect class, so multiple pass managers don't
84 /// need to coordinate their uses of OptBisect.
85 extern ManagedStatic<OptBisect> OptBisector;
86 } // end namespace llvm
87 
88 #endif // LLVM_IR_OPTBISECT_H
Pass interface - Implemented by all 'passes'.
Definition: Pass.h:91
virtual ~OptPassGate()=default
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Extensions to this class implement mechanisms to disable passes and individual optimizations at compi...
Definition: OptBisect.h:26
virtual bool shouldRunPass(const Pass *P, StringRef IRDescription)
IRDescription is a textual description of the IR unit the pass is running over.
Definition: OptBisect.h:32
bool isEnabled() const override
isEnabled() should return true before calling shouldRunPass().
Definition: OptBisect.h:63
virtual bool isEnabled() const
isEnabled() should return true before calling shouldRunPass().
Definition: OptBisect.h:37
This class implements a mechanism to disable passes and individual optimizations at compile time base...
Definition: OptBisect.h:44
#define P(N)
virtual ~OptBisect()=default
ManagedStatic< OptBisect > OptBisector
Singleton instance of the OptBisect class, so multiple pass managers don't need to coordinate their u...
Definition: OptBisect.cpp:58
OptBisect()
Default constructor, initializes the OptBisect state based on the -opt-bisect-limit command line argu...
Definition: OptBisect.cpp:31
static const char PassName[]
print lazy value Lazy Value Info Printer Pass
bool checkPass(const StringRef PassName, const StringRef TargetDesc)
Checks the bisect limit to determine if the specified pass should run.
Definition: OptBisect.cpp:48
bool shouldRunPass(const Pass *P, StringRef IRDescription) override
Checks the bisect limit to determine if the specified pass should run.
Definition: OptBisect.cpp:42
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57