1 //===- LazyValueInfo.h - Value constraint analysis --------------*- 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 // This file defines the interface for lazy computation of value constraint 11 // information. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ANALYSIS_LAZYVALUEINFO_H 16 #define LLVM_ANALYSIS_LAZYVALUEINFO_H 17 18 #include "llvm/Pass.h" 19 20 namespace llvm { 21 class Constant; 22 class TargetData; 23 class Value; 24 25 /// LazyValueInfo - This pass computes, caches, and vends lazy value constraint 26 /// information. 27 class LazyValueInfo : public FunctionPass { 28 class TargetData *TD; 29 void *PImpl; 30 LazyValueInfo(const LazyValueInfo&); // DO NOT IMPLEMENT. 31 void operator=(const LazyValueInfo&); // DO NOT IMPLEMENT. 32 public: 33 static char ID; 34 LazyValueInfo() : FunctionPass(ID), PImpl(0) { 35 initializeLazyValueInfoPass(*PassRegistry::getPassRegistry()); 36 } 37 ~LazyValueInfo() { assert(PImpl == 0 && "releaseMemory not called"); } 38 39 /// Tristate - This is used to return true/false/dunno results. 40 enum Tristate { 41 Unknown = -1, False = 0, True = 1 42 }; 43 44 45 // Public query interface. 46 47 /// getPredicateOnEdge - Determine whether the specified value comparison 48 /// with a constant is known to be true or false on the specified CFG edge. 49 /// Pred is a CmpInst predicate. 50 Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, 51 BasicBlock *FromBB, BasicBlock *ToBB); 52 53 54 /// getConstant - Determine whether the specified value is known to be a 55 /// constant at the end of the specified block. Return null if not. 56 Constant *getConstant(Value *V, BasicBlock *BB); 57 58 /// getConstantOnEdge - Determine whether the specified value is known to be a 59 /// constant on the specified edge. Return null if not. 60 Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB); 61 62 /// threadEdge - Inform the analysis cache that we have threaded an edge from 63 /// PredBB to OldSucc to be from PredBB to NewSucc instead. 64 void threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc); 65 66 /// eraseBlock - Inform the analysis cache that we have erased a block. 67 void eraseBlock(BasicBlock *BB); 68 69 // Implementation boilerplate. 70 71 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 72 AU.setPreservesAll(); 73 } 74 virtual void releaseMemory(); 75 virtual bool runOnFunction(Function &F); 76 }; 77 78 } // end namespace llvm 79 80 #endif 81 82
