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//===- LazyValueInfo.h - Value constraint analysis --------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the interface for lazy computation of value constraint
// information.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LAZYVALUEINFO_H
#define LLVM_ANALYSIS_LAZYVALUEINFO_H
#include "llvm/Pass.h"
namespace llvm {
class AssumptionCache;
class Constant;
class DataLayout;
class DominatorTree;
class Instruction;
class TargetLibraryInfo;
class Value;
/// This pass computes, caches, and vends lazy value constraint information.
class LazyValueInfo : public FunctionPass {
AssumptionCache *AC;
const DataLayout *DL;
class TargetLibraryInfo *TLI;
DominatorTree *DT;
void *PImpl;
LazyValueInfo(const LazyValueInfo&) = delete;
void operator=(const LazyValueInfo&) = delete;
public:
static char ID;
LazyValueInfo() : FunctionPass(ID), PImpl(nullptr) {
initializeLazyValueInfoPass(*PassRegistry::getPassRegistry());
}
~LazyValueInfo() { assert(!PImpl && "releaseMemory not called"); }
/// This is used to return true/false/dunno results.
enum Tristate {
Unknown = -1, False = 0, True = 1
};
// Public query interface.
/// Determine whether the specified value comparison with a constant is known
/// to be true or false on the specified CFG edge.
/// Pred is a CmpInst predicate.
Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
BasicBlock *FromBB, BasicBlock *ToBB,
Instruction *CxtI = nullptr);
/// Determine whether the specified value comparison with a constant is known
/// to be true or false at the specified instruction
/// (from an assume intrinsic). Pred is a CmpInst predicate.
Tristate getPredicateAt(unsigned Pred, Value *V, Constant *C,
Instruction *CxtI);
/// Determine whether the specified value is known to be a
/// constant at the end of the specified block. Return null if not.
Constant *getConstant(Value *V, BasicBlock *BB, Instruction *CxtI = nullptr);
/// Determine whether the specified value is known to be a
/// constant on the specified edge. Return null if not.
Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
Instruction *CxtI = nullptr);
/// Inform the analysis cache that we have threaded an edge from
/// PredBB to OldSucc to be from PredBB to NewSucc instead.
void threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc);
/// Inform the analysis cache that we have erased a block.
void eraseBlock(BasicBlock *BB);
// Implementation boilerplate.
void getAnalysisUsage(AnalysisUsage &AU) const override;
void releaseMemory() override;
bool runOnFunction(Function &F) override;
};
} // end namespace llvm
#endif
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