LazyValueInfo.h revision ac57410a56dbe0eb944699b67f9d84cf986a127e
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; 30 LazyValueInfo(const LazyValueInfo&); // DO NOT IMPLEMENT. 31 void operator=(const LazyValueInfo&); // DO NOT IMPLEMENT. 32public: 33 static char ID; 34 LazyValueInfo() : FunctionPass(&ID), PImpl(0) {} 35 ~LazyValueInfo() { assert(PImpl == 0 && "releaseMemory not called"); } 36 37 /// Tristate - This is used to return true/false/dunno results. 38 enum Tristate { 39 Unknown = -1, False = 0, True = 1 40 }; 41 42 43 // Public query interface. 44 45 /// getPredicateOnEdge - Determine whether the specified value comparison 46 /// with a constant is known to be true or false on the specified CFG edge. 47 /// Pred is a CmpInst predicate. 48 Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, 49 BasicBlock *FromBB, BasicBlock *ToBB); 50 51 52 /// getConstant - Determine whether the specified value is known to be a 53 /// constant at the end of the specified block. Return null if not. 54 Constant *getConstant(Value *V, BasicBlock *BB); 55 56 /// getConstantOnEdge - Determine whether the specified value is known to be a 57 /// constant on the specified edge. Return null if not. 58 Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB); 59 60 61 // Implementation boilerplate. 62 63 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 64 AU.setPreservesAll(); 65 } 66 virtual void releaseMemory(); 67 virtual bool runOnFunction(Function &F); 68}; 69 70} // end namespace llvm 71 72#endif 73 74