LazyValueInfo.h revision cc4d3b25f336eef135cb7125716ecb2c1979e92e
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_LIVEVALUES_H 16#define LLVM_ANALYSIS_LIVEVALUES_H 17 18#include "llvm/Pass.h" 19 20namespace llvm { 21 class Constant; 22 class TargetData; 23 class Value; 24 25/// LazyValueInfo - This pass computes, caches, and vends lazy value constraint 26/// information. 27class LazyValueInfo : public FunctionPass { 28 class TargetData *TD; 29 void *PImpl; 30public: 31 static char ID; 32 LazyValueInfo() : FunctionPass(&ID), PImpl(0) {} 33 34 /// Tristate - This is used to return yes/no/dunno results. 35 enum Tristate { 36 Unknown = -1, No = 0, Yes = 1 37 }; 38 39 40 // Public query interface. 41 42 43 /// isEqual - Determine whether the specified value is known to be equal or 44 /// not-equal to the specified constant at the end of the specified block. 45 Tristate isEqual(Value *V, Constant *C, BasicBlock *BB); 46 47 /// getConstant - Determine whether the specified value is known to be a 48 /// constant at the end of the specified block. Return null if not. 49 Constant *getConstant(Value *V, BasicBlock *BB); 50 51 52 // Implementation boilerplate. 53 54 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 55 AU.setPreservesAll(); 56 } 57 virtual void releaseMemory(); 58 virtual bool runOnFunction(Function &F); 59}; 60 61} // end namespace llvm 62 63#endif 64 65