1//===- LoopPass.h - LoopPass class ----------------------------------------===//
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// This file defines LoopPass class. All loop optimization
10// and transformation passes are derived from LoopPass.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_ANALYSIS_LOOPPASS_H
15#define LLVM_ANALYSIS_LOOPPASS_H
16
17#include "llvm/IR/LegacyPassManagers.h"
18#include "llvm/Pass.h"
19#include <deque>
20
21namespace llvm {
22
23class Loop;
24class LoopInfo;
25class LPPassManager;
26class Function;
27
28class LoopPass : public Pass {
29public:
30 explicit LoopPass(char &pid) : Pass(PT_Loop, pid) {}
31
32 /// getPrinterPass - Get a pass to print the function corresponding
33 /// to a Loop.
34 Pass *createPrinterPass(raw_ostream &O,
35 const std::string &Banner) const override;
36
37 // runOnLoop - This method should be implemented by the subclass to perform
38 // whatever action is necessary for the specified Loop.
39 virtual bool runOnLoop(Loop *L, LPPassManager &LPM) = 0;
40
41 using llvm::Pass::doInitialization;
42 using llvm::Pass::doFinalization;
43
44 // Initialization and finalization hooks.
45 virtual bool doInitialization(Loop *L, LPPassManager &LPM) {
46 return false;
47 }
48
49 // Finalization hook does not supply Loop because at this time
50 // loop nest is completely different.
51 virtual bool doFinalization() { return false; }
52
53 // Check if this pass is suitable for the current LPPassManager, if
54 // available. This pass P is not suitable for a LPPassManager if P
55 // is not preserving higher level analysis info used by other
56 // LPPassManager passes. In such case, pop LPPassManager from the
57 // stack. This will force assignPassManager() to create new
58 // LPPassManger as expected.
59 void preparePassManager(PMStack &PMS) override;
60
61 /// Assign pass manager to manage this pass
62 void assignPassManager(PMStack &PMS, PassManagerType PMT) override;
63
64 /// Return what kind of Pass Manager can manage this pass.
65 PassManagerType getPotentialPassManagerType() const override {
66 return PMT_LoopPassManager;
67 }
68
69protected:
70 /// Optional passes call this function to check whether the pass should be
71 /// skipped. This is the case when Attribute::OptimizeNone is set or when
72 /// optimization bisect is over the limit.
73 bool skipLoop(const Loop *L) const;
74};
75
76class LPPassManager : public FunctionPass, public PMDataManager {
77public:
78 static char ID;
79 explicit LPPassManager();
80
81 /// run - Execute all of the passes scheduled for execution. Keep track of
82 /// whether any of the passes modifies the module, and if so, return true.
83 bool runOnFunction(Function &F) override;
84
85 /// Pass Manager itself does not invalidate any analysis info.
86 // LPPassManager needs LoopInfo.
87 void getAnalysisUsage(AnalysisUsage &Info) const override;
88
89 StringRef getPassName() const override { return "Loop Pass Manager"; }
90
91 PMDataManager *getAsPMDataManager() override { return this; }
92 Pass *getAsPass() override { return this; }
93
94 /// Print passes managed by this manager
95 void dumpPassStructure(unsigned Offset) override;
96
97 LoopPass *getContainedPass(unsigned N) {
98 assert(N < PassVector.size() && "Pass number out of range!");
99 LoopPass *LP = static_cast<LoopPass *>(PassVector[N]);
100 return LP;
101 }
102
103 PassManagerType getPassManagerType() const override {
104 return PMT_LoopPassManager;
105 }
106
107public:
108 // Add a new loop into the loop queue.
109 void addLoop(Loop &L);
110
111 // Mark \p L as deleted.
112 void markLoopAsDeleted(Loop &L);
113
114private:
115 std::deque<Loop *> LQ;
116 LoopInfo *LI;
117 Loop *CurrentLoop;
118 bool CurrentLoopDeleted;
119};
120
121// This pass is required by the LCSSA transformation. It is used inside
122// LPPassManager to check if current pass preserves LCSSA form, and if it does
123// pass manager calls lcssa verification for the current loop.
124struct LCSSAVerificationPass : public FunctionPass {
125 static char ID;
126 LCSSAVerificationPass();
127
128 bool runOnFunction(Function &F) override { return false; }
129
130 void getAnalysisUsage(AnalysisUsage &AU) const override {
131 AU.setPreservesAll();
132 }
133};
134
135} // End llvm namespace
136
137#endif
138

source code of llvm/include/llvm/Analysis/LoopPass.h