//===- LazyValueInfo.h - Value constraint analysis --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the interface for lazy computation of value constraint
// information.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LAZYVALUEINFO_H
#define LLVM_ANALYSIS_LAZYVALUEINFO_H
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
namespace llvm {
class AssumptionCache;
class Constant;
class ConstantRange;
class DataLayout;
class DominatorTree;
class Instruction;
class TargetLibraryInfo;
class Value;
/// This pass computes, caches, and vends lazy value constraint information.
class LazyValueInfo {
friend class LazyValueInfoWrapperPass;
AssumptionCache *AC = nullptr;
const DataLayout *DL = nullptr;
class TargetLibraryInfo *TLI = nullptr;
void *PImpl = nullptr;
LazyValueInfo(const LazyValueInfo&) = delete;
void operator=(const LazyValueInfo&) = delete;
public:
~LazyValueInfo();
LazyValueInfo() = default;
LazyValueInfo(AssumptionCache *AC_, const DataLayout *DL_,
TargetLibraryInfo *TLI_)
: AC(AC_), DL(DL_), TLI(TLI_) {}
LazyValueInfo(LazyValueInfo &&Arg)
: AC(Arg.AC), DL(Arg.DL), TLI(Arg.TLI), PImpl(Arg.PImpl) {
Arg.PImpl = nullptr;
}
LazyValueInfo &operator=(LazyValueInfo &&Arg) {
releaseMemory();
AC = Arg.AC;
DL = Arg.DL;
TLI = Arg.TLI;
PImpl = Arg.PImpl;
Arg.PImpl = nullptr;
return *this;
}
/// 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.
/// \p Pred is a CmpInst predicate. If \p UseBlockValue is true, the block
/// value is also taken into account.
Tristate getPredicateAt(unsigned Pred, Value *V, Constant *C,
Instruction *CxtI, bool UseBlockValue);
/// Determine whether the specified value comparison is known to be true
/// or false at the specified instruction. While this takes two Value's,
/// it still requires that one of them is a constant.
/// \p Pred is a CmpInst predicate.
/// If \p UseBlockValue is true, the block value is also taken into account.
Tristate getPredicateAt(unsigned Pred, Value *LHS, Value *RHS,
Instruction *CxtI, bool UseBlockValue);
/// Determine whether the specified value is known to be a constant at the
/// specified instruction. Return null if not.
Constant *getConstant(Value *V, Instruction *CxtI);
/// Return the ConstantRange constraint that is known to hold for the
/// specified value at the specified instruction. This may only be called
/// on integer-typed Values.
ConstantRange getConstantRange(Value *V, Instruction *CxtI,
bool UndefAllowed = true);
/// Return the ConstantRange constraint that is known to hold for the value
/// at a specific use-site.
ConstantRange getConstantRangeAtUse(const Use &U, bool UndefAllowed = true);
/// 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);
/// Return the ConstantRage constraint that is known to hold for the
/// specified value on the specified edge. This may be only be called
/// on integer-typed Values.
ConstantRange getConstantRangeOnEdge(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);
/// Complete flush all previously computed values
void clear(const Module *M);
/// Print the \LazyValueInfo Analysis.
/// We pass in the DTree that is required for identifying which basic blocks
/// we can solve/print for, in the LVIPrinter.
void printLVI(Function &F, DominatorTree &DTree, raw_ostream &OS);
// For old PM pass. Delete once LazyValueInfoWrapperPass is gone.
void releaseMemory();
/// Handle invalidation events in the new pass manager.
bool invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &Inv);
};
/// Analysis to compute lazy value information.
class LazyValueAnalysis : public AnalysisInfoMixin<LazyValueAnalysis> {
public:
typedef LazyValueInfo Result;
Result run(Function &F, FunctionAnalysisManager &FAM);
private:
static AnalysisKey Key;
friend struct AnalysisInfoMixin<LazyValueAnalysis>;
};
/// Wrapper around LazyValueInfo.
class LazyValueInfoWrapperPass : public FunctionPass {
LazyValueInfoWrapperPass(const LazyValueInfoWrapperPass&) = delete;
void operator=(const LazyValueInfoWrapperPass&) = delete;
public:
static char ID;
LazyValueInfoWrapperPass();
~LazyValueInfoWrapperPass() override {
assert(!Info.PImpl && "releaseMemory not called");
}
LazyValueInfo &getLVI();
void getAnalysisUsage(AnalysisUsage &AU) const override;
void releaseMemory() override;
bool runOnFunction(Function &F) override;
private:
LazyValueInfo Info;
};
} // end namespace llvm
#endif