LazyValueInfo.h revision b52675b643db496bcea218bd3d5fc5e23f523c22
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 true/false/dunno results. 35 enum Tristate { 36 Unknown = -1, False = 0, True = 1 37 }; 38 39 40 // Public query interface. 41 42 /// getPredicateOnEdge - Determine whether the specified value comparison 43 /// with a constant is known to be true or false on the specified CFG edge. 44 /// Pred is a CmpInst predicate. 45 Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, 46 BasicBlock *FromBB, BasicBlock *ToBB); 47 48 49 /// getConstant - Determine whether the specified value is known to be a 50 /// constant at the end of the specified block. Return null if not. 51 Constant *getConstant(Value *V, BasicBlock *BB); 52 53 /// getConstantOnEdge - Determine whether the specified value is known to be a 54 /// constant on the specified edge. Return null if not. 55 Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB); 56 57 58 // Implementation boilerplate. 59 60 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 61 AU.setPreservesAll(); 62 } 63 virtual void releaseMemory(); 64 virtual bool runOnFunction(Function &F); 65}; 66 67} // end namespace llvm 68 69#endif 70 71