1 //===- llvm/InstVisitor.h - Instruction visitor templates -------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 11 #ifndef LLVM_INSTVISITOR_H 12 #define LLVM_INSTVISITOR_H 13 14 #include "llvm/IR/Function.h" 15 #include "llvm/IR/Instructions.h" 16 #include "llvm/IR/IntrinsicInst.h" 17 #include "llvm/IR/Intrinsics.h" 18 #include "llvm/IR/Module.h" 19 #include "llvm/Support/CallSite.h" 20 #include "llvm/Support/ErrorHandling.h" 21 22 namespace llvm { 23 24 // We operate on opaque instruction classes, so forward declare all instruction 25 // types now... 26 // 27 #define HANDLE_INST(NUM, OPCODE, CLASS) class CLASS; 28 #include "llvm/IR/Instruction.def" 29 30 #define DELEGATE(CLASS_TO_VISIT) \ 31 return static_cast<SubClass*>(this)-> \ 32 visit##CLASS_TO_VISIT(static_cast<CLASS_TO_VISIT&>(I)) 33 34 35 /// @brief Base class for instruction visitors 36 /// 37 /// Instruction visitors are used when you want to perform different actions 38 /// for different kinds of instructions without having to use lots of casts 39 /// and a big switch statement (in your code, that is). 40 /// 41 /// To define your own visitor, inherit from this class, specifying your 42 /// new type for the 'SubClass' template parameter, and "override" visitXXX 43 /// functions in your class. I say "override" because this class is defined 44 /// in terms of statically resolved overloading, not virtual functions. 45 /// 46 /// For example, here is a visitor that counts the number of malloc 47 /// instructions processed: 48 /// 49 /// /// Declare the class. Note that we derive from InstVisitor instantiated 50 /// /// with _our new subclasses_ type. 51 /// /// 52 /// struct CountAllocaVisitor : public InstVisitor<CountAllocaVisitor> { 53 /// unsigned Count; 54 /// CountAllocaVisitor() : Count(0) {} 55 /// 56 /// void visitAllocaInst(AllocaInst &AI) { ++Count; } 57 /// }; 58 /// 59 /// And this class would be used like this: 60 /// CountAllocaVisitor CAV; 61 /// CAV.visit(function); 62 /// NumAllocas = CAV.Count; 63 /// 64 /// The defined has 'visit' methods for Instruction, and also for BasicBlock, 65 /// Function, and Module, which recursively process all contained instructions. 66 /// 67 /// Note that if you don't implement visitXXX for some instruction type, 68 /// the visitXXX method for instruction superclass will be invoked. So 69 /// if instructions are added in the future, they will be automatically 70 /// supported, if you handle one of their superclasses. 71 /// 72 /// The optional second template argument specifies the type that instruction 73 /// visitation functions should return. If you specify this, you *MUST* provide 74 /// an implementation of visitInstruction though!. 75 /// 76 /// Note that this class is specifically designed as a template to avoid 77 /// virtual function call overhead. Defining and using an InstVisitor is just 78 /// as efficient as having your own switch statement over the instruction 79 /// opcode. 80 template<typename SubClass, typename RetTy=void> 81 class InstVisitor { 82 //===--------------------------------------------------------------------===// 83 // Interface code - This is the public interface of the InstVisitor that you 84 // use to visit instructions... 85 // 86 87 public: 88 // Generic visit method - Allow visitation to all instructions in a range 89 template<class Iterator> 90 void visit(Iterator Start, Iterator End) { 91 while (Start != End) 92 static_cast<SubClass*>(this)->visit(*Start++); 93 } 94 95 // Define visitors for functions and basic blocks... 96 // 97 void visit(Module &M) { 98 static_cast<SubClass*>(this)->visitModule(M); 99 visit(M.begin(), M.end()); 100 } 101 void visit(Function &F) { 102 static_cast<SubClass*>(this)->visitFunction(F); 103 visit(F.begin(), F.end()); 104 } 105 void visit(BasicBlock &BB) { 106 static_cast<SubClass*>(this)->visitBasicBlock(BB); 107 visit(BB.begin(), BB.end()); 108 } 109 110 // Forwarding functions so that the user can visit with pointers AND refs. 111 void visit(Module *M) { visit(*M); } 112 void visit(Function *F) { visit(*F); } 113 void visit(BasicBlock *BB) { visit(*BB); } 114 RetTy visit(Instruction *I) { return visit(*I); } 115 116 // visit - Finally, code to visit an instruction... 117 // 118 RetTy visit(Instruction &I) { 119 switch (I.getOpcode()) { 120 default: llvm_unreachable("Unknown instruction type encountered!"); 121 // Build the switch statement using the Instruction.def file... 122 #define HANDLE_INST(NUM, OPCODE, CLASS) \ 123 case Instruction::OPCODE: return \ 124 static_cast<SubClass*>(this)-> \ 125 visit##OPCODE(static_cast<CLASS&>(I)); 126 #include "llvm/IR/Instruction.def" 127 } 128 } 129 130 //===--------------------------------------------------------------------===// 131 // Visitation functions... these functions provide default fallbacks in case 132 // the user does not specify what to do for a particular instruction type. 133 // The default behavior is to generalize the instruction type to its subtype 134 // and try visiting the subtype. All of this should be inlined perfectly, 135 // because there are no virtual functions to get in the way. 136 // 137 138 // When visiting a module, function or basic block directly, these methods get 139 // called to indicate when transitioning into a new unit. 140 // 141 void visitModule (Module &M) {} 142 void visitFunction (Function &F) {} 143 void visitBasicBlock(BasicBlock &BB) {} 144 145 // Define instruction specific visitor functions that can be overridden to 146 // handle SPECIFIC instructions. These functions automatically define 147 // visitMul to proxy to visitBinaryOperator for instance in case the user does 148 // not need this generality. 149 // 150 // These functions can also implement fan-out, when a single opcode and 151 // instruction have multiple more specific Instruction subclasses. The Call 152 // instruction currently supports this. We implement that by redirecting that 153 // instruction to a special delegation helper. 154 #define HANDLE_INST(NUM, OPCODE, CLASS) \ 155 RetTy visit##OPCODE(CLASS &I) { \ 156 if (NUM == Instruction::Call) \ 157 return delegateCallInst(I); \ 158 else \ 159 DELEGATE(CLASS); \ 160 } 161 #include "llvm/IR/Instruction.def" 162 163 // Specific Instruction type classes... note that all of the casts are 164 // necessary because we use the instruction classes as opaque types... 165 // 166 RetTy visitReturnInst(ReturnInst &I) { DELEGATE(TerminatorInst);} 167 RetTy visitBranchInst(BranchInst &I) { DELEGATE(TerminatorInst);} 168 RetTy visitSwitchInst(SwitchInst &I) { DELEGATE(TerminatorInst);} 169 RetTy visitIndirectBrInst(IndirectBrInst &I) { DELEGATE(TerminatorInst);} 170 RetTy visitResumeInst(ResumeInst &I) { DELEGATE(TerminatorInst);} 171 RetTy visitUnreachableInst(UnreachableInst &I) { DELEGATE(TerminatorInst);} 172 RetTy visitICmpInst(ICmpInst &I) { DELEGATE(CmpInst);} 173 RetTy visitFCmpInst(FCmpInst &I) { DELEGATE(CmpInst);} 174 RetTy visitAllocaInst(AllocaInst &I) { DELEGATE(UnaryInstruction);} 175 RetTy visitLoadInst(LoadInst &I) { DELEGATE(UnaryInstruction);} 176 RetTy visitStoreInst(StoreInst &I) { DELEGATE(Instruction);} 177 RetTy visitAtomicCmpXchgInst(AtomicCmpXchgInst &I) { DELEGATE(Instruction);} 178 RetTy visitAtomicRMWInst(AtomicRMWInst &I) { DELEGATE(Instruction);} 179 RetTy visitFenceInst(FenceInst &I) { DELEGATE(Instruction);} 180 RetTy visitGetElementPtrInst(GetElementPtrInst &I){ DELEGATE(Instruction);} 181 RetTy visitPHINode(PHINode &I) { DELEGATE(Instruction);} 182 RetTy visitTruncInst(TruncInst &I) { DELEGATE(CastInst);} 183 RetTy visitZExtInst(ZExtInst &I) { DELEGATE(CastInst);} 184 RetTy visitSExtInst(SExtInst &I) { DELEGATE(CastInst);} 185 RetTy visitFPTruncInst(FPTruncInst &I) { DELEGATE(CastInst);} 186 RetTy visitFPExtInst(FPExtInst &I) { DELEGATE(CastInst);} 187 RetTy visitFPToUIInst(FPToUIInst &I) { DELEGATE(CastInst);} 188 RetTy visitFPToSIInst(FPToSIInst &I) { DELEGATE(CastInst);} 189 RetTy visitUIToFPInst(UIToFPInst &I) { DELEGATE(CastInst);} 190 RetTy visitSIToFPInst(SIToFPInst &I) { DELEGATE(CastInst);} 191 RetTy visitPtrToIntInst(PtrToIntInst &I) { DELEGATE(CastInst);} 192 RetTy visitIntToPtrInst(IntToPtrInst &I) { DELEGATE(CastInst);} 193 RetTy visitBitCastInst(BitCastInst &I) { DELEGATE(CastInst);} 194 RetTy visitSelectInst(SelectInst &I) { DELEGATE(Instruction);} 195 RetTy visitVAArgInst(VAArgInst &I) { DELEGATE(UnaryInstruction);} 196 RetTy visitExtractElementInst(ExtractElementInst &I) { DELEGATE(Instruction);} 197 RetTy visitInsertElementInst(InsertElementInst &I) { DELEGATE(Instruction);} 198 RetTy visitShuffleVectorInst(ShuffleVectorInst &I) { DELEGATE(Instruction);} 199 RetTy visitExtractValueInst(ExtractValueInst &I){ DELEGATE(UnaryInstruction);} 200 RetTy visitInsertValueInst(InsertValueInst &I) { DELEGATE(Instruction); } 201 RetTy visitLandingPadInst(LandingPadInst &I) { DELEGATE(Instruction); } 202 203 // Handle the special instrinsic instruction classes. 204 RetTy visitDbgDeclareInst(DbgDeclareInst &I) { DELEGATE(DbgInfoIntrinsic);} 205 RetTy visitDbgValueInst(DbgValueInst &I) { DELEGATE(DbgInfoIntrinsic);} 206 RetTy visitDbgInfoIntrinsic(DbgInfoIntrinsic &I) { DELEGATE(IntrinsicInst); } 207 RetTy visitMemSetInst(MemSetInst &I) { DELEGATE(MemIntrinsic); } 208 RetTy visitMemCpyInst(MemCpyInst &I) { DELEGATE(MemTransferInst); } 209 RetTy visitMemMoveInst(MemMoveInst &I) { DELEGATE(MemTransferInst); } 210 RetTy visitMemTransferInst(MemTransferInst &I) { DELEGATE(MemIntrinsic); } 211 RetTy visitMemIntrinsic(MemIntrinsic &I) { DELEGATE(IntrinsicInst); } 212 RetTy visitVAStartInst(VAStartInst &I) { DELEGATE(IntrinsicInst); } 213 RetTy visitVAEndInst(VAEndInst &I) { DELEGATE(IntrinsicInst); } 214 RetTy visitVACopyInst(VACopyInst &I) { DELEGATE(IntrinsicInst); } 215 RetTy visitIntrinsicInst(IntrinsicInst &I) { DELEGATE(CallInst); } 216 217 // Call and Invoke are slightly different as they delegate first through 218 // a generic CallSite visitor. 219 RetTy visitCallInst(CallInst &I) { 220 return static_cast<SubClass*>(this)->visitCallSite(&I); 221 } 222 RetTy visitInvokeInst(InvokeInst &I) { 223 return static_cast<SubClass*>(this)->visitCallSite(&I); 224 } 225 226 // Next level propagators: If the user does not overload a specific 227 // instruction type, they can overload one of these to get the whole class 228 // of instructions... 229 // 230 RetTy visitCastInst(CastInst &I) { DELEGATE(UnaryInstruction);} 231 RetTy visitBinaryOperator(BinaryOperator &I) { DELEGATE(Instruction);} 232 RetTy visitCmpInst(CmpInst &I) { DELEGATE(Instruction);} 233 RetTy visitTerminatorInst(TerminatorInst &I) { DELEGATE(Instruction);} 234 RetTy visitUnaryInstruction(UnaryInstruction &I){ DELEGATE(Instruction);} 235 236 // Provide a special visitor for a 'callsite' that visits both calls and 237 // invokes. When unimplemented, properly delegates to either the terminator or 238 // regular instruction visitor. 239 RetTy visitCallSite(CallSite CS) { 240 assert(CS); 241 Instruction &I = *CS.getInstruction(); 242 if (CS.isCall()) 243 DELEGATE(Instruction); 244 245 assert(CS.isInvoke()); 246 DELEGATE(TerminatorInst); 247 } 248 249 // If the user wants a 'default' case, they can choose to override this 250 // function. If this function is not overloaded in the user's subclass, then 251 // this instruction just gets ignored. 252 // 253 // Note that you MUST override this function if your return type is not void. 254 // 255 void visitInstruction(Instruction &I) {} // Ignore unhandled instructions 256 257 private: 258 // Special helper function to delegate to CallInst subclass visitors. 259 RetTy delegateCallInst(CallInst &I) { 260 if (const Function *F = I.getCalledFunction()) { 261 switch ((Intrinsic::ID)F->getIntrinsicID()) { 262 default: DELEGATE(IntrinsicInst); 263 case Intrinsic::dbg_declare: DELEGATE(DbgDeclareInst); 264 case Intrinsic::dbg_value: DELEGATE(DbgValueInst); 265 case Intrinsic::memcpy: DELEGATE(MemCpyInst); 266 case Intrinsic::memmove: DELEGATE(MemMoveInst); 267 case Intrinsic::memset: DELEGATE(MemSetInst); 268 case Intrinsic::vastart: DELEGATE(VAStartInst); 269 case Intrinsic::vaend: DELEGATE(VAEndInst); 270 case Intrinsic::vacopy: DELEGATE(VACopyInst); 271 case Intrinsic::not_intrinsic: break; 272 } 273 } 274 DELEGATE(CallInst); 275 } 276 277 // An overload that will never actually be called, it is used only from dead 278 // code in the dispatching from opcodes to instruction subclasses. 279 RetTy delegateCallInst(Instruction &I) { 280 llvm_unreachable("delegateCallInst called for non-CallInst"); 281 } 282 }; 283 284 #undef DELEGATE 285 286 } // End llvm namespace 287 288 #endif 289
