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 | |
21 | namespace llvm { |
22 | |
23 | class Loop; |
24 | class LoopInfo; |
25 | class LPPassManager; |
26 | class Function; |
27 | |
28 | class LoopPass : public Pass { |
29 | public: |
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 | |
69 | protected: |
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 | |
76 | class LPPassManager : public FunctionPass, public PMDataManager { |
77 | public: |
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 | |
107 | public: |
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 | |
114 | private: |
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. |
124 | struct 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 | |