aboutsummaryrefslogtreecommitdiff
path: root/include/llvm/Support/InstVisitor.h
blob: 597cc9d905421355bcfd10e1195e6d8cfbe8fad1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
//===- llvm/Support/InstVisitor.h - Define instruction visitors -*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//


#ifndef LLVM_SUPPORT_INSTVISITOR_H
#define LLVM_SUPPORT_INSTVISITOR_H

#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"

namespace llvm {

// We operate on opaque instruction classes, so forward declare all instruction
// types now...
//
#define HANDLE_INST(NUM, OPCODE, CLASS)   class CLASS;
#include "llvm/Instruction.def"

#define DELEGATE(CLASS_TO_VISIT) \
  return static_cast<SubClass*>(this)-> \
               visit##CLASS_TO_VISIT(static_cast<CLASS_TO_VISIT&>(I))


/// @brief Base class for instruction visitors
///
/// Instruction visitors are used when you want to perform different action for
/// different kinds of instruction without without having to use lots of casts
/// and a big switch statement (in your code that is).
///
/// To define your own visitor, inherit from this class, specifying your
/// new type for the 'SubClass' template parameter, and "override" visitXXX
/// functions in your class. I say "overriding" because this class is defined
/// in terms of statically resolved overloading, not virtual functions.
///
/// For example, here is a visitor that counts the number of malloc
/// instructions processed:
///
///  /// Declare the class.  Note that we derive from InstVisitor instantiated
///  /// with _our new subclasses_ type.
///  ///
///  struct CountMallocVisitor : public InstVisitor<CountMallocVisitor> {
///    unsigned Count;
///    CountMallocVisitor() : Count(0) {}
///
///    void visitMallocInst(MallocInst &MI) { ++Count; }
///  };
///
///  And this class would be used like this:
///    CountMallocVistor CMV;
///    CMV.visit(function);
///    NumMallocs = CMV.Count;
///
/// The defined has 'visit' methods for Instruction, and also for BasicBlock,
/// Function, and Module, which recursively process all conained instructions.
///
/// Note that if you don't implement visitXXX for some instruction type,
/// the visitXXX method for instruction superclass will be invoked. So
/// if instructions are added in the future, they will be automatically
/// supported, if you handle on of their superclasses.
///
/// The optional second template argument specifies the type that instruction
/// visitation functions should return. If you specify this, you *MUST* provide
/// an implementation of visitInstruction though!.
///
/// Note that this class is specifically designed as a template to avoid
/// virtual function call overhead.  Defining and using an InstVisitor is just
/// as efficient as having your own switch statement over the instruction
/// opcode.
template<typename SubClass, typename RetTy=void>
class InstVisitor {
  //===--------------------------------------------------------------------===//
  // Interface code - This is the public interface of the InstVisitor that you
  // use to visit instructions...
  //

public:
  // Generic visit method - Allow visitation to all instructions in a range
  template<class Iterator>
  void visit(Iterator Start, Iterator End) {
    while (Start != End)
      static_cast<SubClass*>(this)->visit(*Start++);
  }

  // Define visitors for functions and basic blocks...
  //
  void visit(Module &M) {
    static_cast<SubClass*>(this)->visitModule(M);
    visit(M.begin(), M.end());
  }
  void visit(Function &F) {
    static_cast<SubClass*>(this)->visitFunction(F);
    visit(F.begin(), F.end());
  }
  void visit(BasicBlock &BB) {
    static_cast<SubClass*>(this)->visitBasicBlock(BB);
    visit(BB.begin(), BB.end());
  }

  // Forwarding functions so that the user can visit with pointers AND refs.
  void visit(Module       *M)  { visit(*M); }
  void visit(Function     *F)  { visit(*F); }
  void visit(BasicBlock   *BB) { visit(*BB); }
  RetTy visit(Instruction *I)  { return visit(*I); }

  // visit - Finally, code to visit an instruction...
  //
  RetTy visit(Instruction &I) {
    switch (I.getOpcode()) {
    default: assert(0 && "Unknown instruction type encountered!");
             abort();
      // Build the switch statement using the Instruction.def file...
#define HANDLE_INST(NUM, OPCODE, CLASS) \
    case Instruction::OPCODE: return \
           static_cast<SubClass*>(this)-> \
                      visit##OPCODE(static_cast<CLASS&>(I));
#include "llvm/Instruction.def"
    }
  }

  //===--------------------------------------------------------------------===//
  // Visitation functions... these functions provide default fallbacks in case
  // the user does not specify what to do for a particular instruction type.
  // The default behavior is to generalize the instruction type to its subtype
  // and try visiting the subtype.  All of this should be inlined perfectly,
  // because there are no virtual functions to get in the way.
  //

  // When visiting a module, function or basic block directly, these methods get
  // called to indicate when transitioning into a new unit.
  //
  void visitModule    (Module &M) {}
  void visitFunction  (Function &F) {}
  void visitBasicBlock(BasicBlock &BB) {}

  // Define instruction specific visitor functions that can be overridden to
  // handle SPECIFIC instructions.  These functions automatically define
  // visitMul to proxy to visitBinaryOperator for instance in case the user does
  // not need this generality.
  //
  // The one problem case we have to handle here though is that the PHINode
  // class and opcode name are the exact same.  Because of this, we cannot
  // define visitPHINode (the inst version) to forward to visitPHINode (the
  // generic version) without multiply defined symbols and recursion.  To handle
  // this, we do not autoexpand "Other" instructions, we do it manually.
  //
#define HANDLE_INST(NUM, OPCODE, CLASS) \
    RetTy visit##OPCODE(CLASS &I) { DELEGATE(CLASS); }
#include "llvm/Instruction.def"

  // Specific Instruction type classes... note that all of the casts are
  // necessary because we use the instruction classes as opaque types...
  //
  RetTy visitReturnInst(ReturnInst &I)              { DELEGATE(TerminatorInst);}
  RetTy visitBranchInst(BranchInst &I)              { DELEGATE(TerminatorInst);}
  RetTy visitSwitchInst(SwitchInst &I)              { DELEGATE(TerminatorInst);}
  RetTy visitInvokeInst(InvokeInst &I)              { DELEGATE(TerminatorInst);}
  RetTy visitUnwindInst(UnwindInst &I)              { DELEGATE(TerminatorInst);}
  RetTy visitUnreachableInst(UnreachableInst &I)    { DELEGATE(TerminatorInst);}
  RetTy visitICmpInst(ICmpInst &I)                  { DELEGATE(CmpInst);}
  RetTy visitFCmpInst(FCmpInst &I)                  { DELEGATE(CmpInst);}
  RetTy visitVICmpInst(VICmpInst &I)                { DELEGATE(CmpInst);}
  RetTy visitVFCmpInst(VFCmpInst &I)                { DELEGATE(CmpInst);}
  RetTy visitMallocInst(MallocInst &I)              { DELEGATE(AllocationInst);}
  RetTy visitAllocaInst(AllocaInst &I)              { DELEGATE(AllocationInst);}
  RetTy visitFreeInst(FreeInst     &I)              { DELEGATE(Instruction); }
  RetTy visitLoadInst(LoadInst     &I)              { DELEGATE(Instruction); }
  RetTy visitStoreInst(StoreInst   &I)              { DELEGATE(Instruction); }
  RetTy visitGetElementPtrInst(GetElementPtrInst &I){ DELEGATE(Instruction); }
  RetTy visitPHINode(PHINode       &I)              { DELEGATE(Instruction); }
  RetTy visitTruncInst(TruncInst &I)                { DELEGATE(CastInst); }
  RetTy visitZExtInst(ZExtInst &I)                  { DELEGATE(CastInst); }
  RetTy visitSExtInst(SExtInst &I)                  { DELEGATE(CastInst); }
  RetTy visitFPTruncInst(FPTruncInst &I)            { DELEGATE(CastInst); }
  RetTy visitFPExtInst(FPExtInst &I)                { DELEGATE(CastInst); }
  RetTy visitFPToUIInst(FPToUIInst &I)              { DELEGATE(CastInst); }
  RetTy visitFPToSIInst(FPToSIInst &I)              { DELEGATE(CastInst); }
  RetTy visitUIToFPInst(UIToFPInst &I)              { DELEGATE(CastInst); }
  RetTy visitSIToFPInst(SIToFPInst &I)              { DELEGATE(CastInst); }
  RetTy visitPtrToIntInst(PtrToIntInst &I)          { DELEGATE(CastInst); }
  RetTy visitIntToPtrInst(IntToPtrInst &I)          { DELEGATE(CastInst); }
  RetTy visitBitCastInst(BitCastInst &I)            { DELEGATE(CastInst); }
  RetTy visitSelectInst(SelectInst &I)              { DELEGATE(Instruction); }
  RetTy visitCallInst(CallInst     &I)              { DELEGATE(Instruction); }
  RetTy visitVAArgInst(VAArgInst   &I)              { DELEGATE(Instruction); }
  RetTy visitExtractElementInst(ExtractElementInst &I) { DELEGATE(Instruction);}
  RetTy visitInsertElementInst(InsertElementInst &I) { DELEGATE(Instruction); }
  RetTy visitShuffleVectorInst(ShuffleVectorInst &I) { DELEGATE(Instruction); }
  RetTy visitExtractValueInst(ExtractValueInst &I)  { DELEGATE(Instruction);}
  RetTy visitInsertValueInst(InsertValueInst &I)    { DELEGATE(Instruction); }

  // Next level propagators... if the user does not overload a specific
  // instruction type, they can overload one of these to get the whole class
  // of instructions...
  //
  RetTy visitTerminatorInst(TerminatorInst &I) { DELEGATE(Instruction); }
  RetTy visitBinaryOperator(BinaryOperator &I) { DELEGATE(Instruction); }
  RetTy visitAllocationInst(AllocationInst &I) { DELEGATE(Instruction); }
  RetTy visitCmpInst(CmpInst &I)               { DELEGATE(Instruction); }
  RetTy visitCastInst(CastInst &I)             { DELEGATE(Instruction); }

  // If the user wants a 'default' case, they can choose to override this
  // function.  If this function is not overloaded in the users subclass, then
  // this instruction just gets ignored.
  //
  // Note that you MUST override this function if your return type is not void.
  //
  void visitInstruction(Instruction &I) {}  // Ignore unhandled instructions
};

#undef DELEGATE

} // End llvm namespace

#endif