LLVM  9.0.0svn
CallGraphSCCPass.h
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1 //===- CallGraphSCCPass.h - Pass that operates BU on call graph -*- 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 // This file defines the CallGraphSCCPass class, which is used for passes which
10 // are implemented as bottom-up traversals on the call graph. Because there may
11 // be cycles in the call graph, passes of this type operate on the call-graph in
12 // SCC order: that is, they process function bottom-up, except for recursive
13 // functions, which they process all at once.
14 //
15 // These passes are inherently interprocedural, and are required to keep the
16 // call graph up-to-date if they do anything which could modify it.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #ifndef LLVM_ANALYSIS_CALLGRAPHSCCPASS_H
21 #define LLVM_ANALYSIS_CALLGRAPHSCCPASS_H
22 
23 #include "llvm/ADT/ArrayRef.h"
24 #include "llvm/Pass.h"
25 #include <vector>
26 
27 namespace llvm {
28 
29 class CallGraph;
30 class CallGraphNode;
31 class CallGraphSCC;
32 class PMStack;
33 
34 class CallGraphSCCPass : public Pass {
35 public:
36  explicit CallGraphSCCPass(char &pid) : Pass(PT_CallGraphSCC, pid) {}
37 
38  /// createPrinterPass - Get a pass that prints the Module
39  /// corresponding to a CallGraph.
41  const std::string &Banner) const override;
42 
45 
46  /// doInitialization - This method is called before the SCC's of the program
47  /// has been processed, allowing the pass to do initialization as necessary.
48  virtual bool doInitialization(CallGraph &CG) {
49  return false;
50  }
51 
52  /// runOnSCC - This method should be implemented by the subclass to perform
53  /// whatever action is necessary for the specified SCC. Note that
54  /// non-recursive (or only self-recursive) functions will have an SCC size of
55  /// 1, where recursive portions of the call graph will have SCC size > 1.
56  ///
57  /// SCC passes that add or delete functions to the SCC are required to update
58  /// the SCC list, otherwise stale pointers may be dereferenced.
59  virtual bool runOnSCC(CallGraphSCC &SCC) = 0;
60 
61  /// doFinalization - This method is called after the SCC's of the program has
62  /// been processed, allowing the pass to do final cleanup as necessary.
63  virtual bool doFinalization(CallGraph &CG) {
64  return false;
65  }
66 
67  /// Assign pass manager to manager this pass
68  void assignPassManager(PMStack &PMS, PassManagerType PMT) override;
69 
70  /// Return what kind of Pass Manager can manage this pass.
73  }
74 
75  /// getAnalysisUsage - For this class, we declare that we require and preserve
76  /// the call graph. If the derived class implements this method, it should
77  /// always explicitly call the implementation here.
78  void getAnalysisUsage(AnalysisUsage &Info) const override;
79 
80 protected:
81  /// Optional passes call this function to check whether the pass should be
82  /// skipped. This is the case when optimization bisect is over the limit.
83  bool skipSCC(CallGraphSCC &SCC) const;
84 };
85 
86 /// CallGraphSCC - This is a single SCC that a CallGraphSCCPass is run on.
87 class CallGraphSCC {
88  const CallGraph &CG; // The call graph for this SCC.
89  void *Context; // The CGPassManager object that is vending this.
90  std::vector<CallGraphNode *> Nodes;
91 
92 public:
93  CallGraphSCC(CallGraph &cg, void *context) : CG(cg), Context(context) {}
94 
96  Nodes.assign(NewNodes.begin(), NewNodes.end());
97  }
98 
99  bool isSingular() const { return Nodes.size() == 1; }
100  unsigned size() const { return Nodes.size(); }
101 
102  /// ReplaceNode - This informs the SCC and the pass manager that the specified
103  /// Old node has been deleted, and New is to be used in its place.
104  void ReplaceNode(CallGraphNode *Old, CallGraphNode *New);
105 
106  using iterator = std::vector<CallGraphNode *>::const_iterator;
107 
108  iterator begin() const { return Nodes.begin(); }
109  iterator end() const { return Nodes.end(); }
110 
111  const CallGraph &getCallGraph() { return CG; }
112 };
113 
115 
116 /// This pass is required by interprocedural register allocation. It forces
117 /// codegen to follow bottom up order on call graph.
119 public:
120  static char ID;
121 
125  }
126 
127  bool runOnSCC(CallGraphSCC &SCC) override { return false; }
128 
129  void getAnalysisUsage(AnalysisUsage &AU) const override {
130  AU.setPreservesAll();
131  }
132 };
133 
134 } // end namespace llvm
135 
136 #endif // LLVM_ANALYSIS_CALLGRAPHSCCPASS_H
Pass interface - Implemented by all &#39;passes&#39;.
Definition: Pass.h:80
PassManagerType
Different types of internal pass managers.
Definition: Pass.h:53
bool runOnSCC(CallGraphSCC &SCC) override
runOnSCC - This method should be implemented by the subclass to perform whatever action is necessary ...
CGPassManager.
Definition: Pass.h:56
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
LLVMContext & Context
This class represents lattice values for constants.
Definition: AllocatorList.h:23
iterator begin() const
Definition: ArrayRef.h:136
iterator end() const
A global registry used in conjunction with static constructors to make pluggable components (like tar...
Definition: Registry.h:44
virtual bool doInitialization(CallGraph &CG)
doInitialization - This method is called before the SCC&#39;s of the program has been processed...
A node in the call graph for a module.
Definition: CallGraph.h:164
bool skipSCC(CallGraphSCC &SCC) const
Optional passes call this function to check whether the pass should be skipped.
void getAnalysisUsage(AnalysisUsage &Info) const override
getAnalysisUsage - For this class, we declare that we require and preserve the call graph...
Pass * createPrinterPass(raw_ostream &OS, const std::string &Banner) const override
createPrinterPass - Get a pass that prints the Module corresponding to a CallGraph.
virtual bool doFinalization(Module &)
doFinalization - Virtual method overriden by subclasses to do any necessary clean up after all passes...
Definition: Pass.h:109
const CallGraph & getCallGraph()
PMStack - This class implements a stack data structure of PMDataManager pointers. ...
bool isSingular() const
unsigned size() const
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:32
Analysis containing CSE Info
Definition: CSEInfo.cpp:20
virtual bool doInitialization(Module &)
doInitialization - Virtual method overridden by subclasses to do any necessary initialization before ...
Definition: Pass.h:105
iterator begin() const
This pass is required by interprocedural register allocation.
Represent the analysis usage information of a pass.
PassManagerType getPotentialPassManagerType() const override
Return what kind of Pass Manager can manage this pass.
void initialize(ArrayRef< CallGraphNode *> NewNodes)
void assignPassManager(PMStack &PMS, PassManagerType PMT) override
Assign pass manager to manager this pass.
void initializeDummyCGSCCPassPass(PassRegistry &)
iterator end() const
Definition: ArrayRef.h:137
void setPreservesAll()
Set by analyses that do not transform their input at all.
The basic data container for the call graph of a Module of IR.
Definition: CallGraph.h:73
std::vector< CallGraphNode * >::const_iterator iterator
CallGraphSCC(CallGraph &cg, void *context)
virtual bool doFinalization(CallGraph &CG)
doFinalization - This method is called after the SCC&#39;s of the program has been processed, allowing the pass to do final cleanup as necessary.
virtual bool runOnSCC(CallGraphSCC &SCC)=0
runOnSCC - This method should be implemented by the subclass to perform whatever action is necessary ...
CallGraphSCC - This is a single SCC that a CallGraphSCCPass is run on.
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
PassRegistry - This class manages the registration and intitialization of the pass subsystem as appli...
Definition: PassRegistry.h:38
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - For this class, we declare that we require and preserve the call graph...