================ @@ -0,0 +1,112 @@ +//===-- NullPointerAnalysisModel.h ------------------------------*- 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 a generic null-pointer analysis model, used for finding +// pointer null-checks after the pointer has already been dereferenced. +// +// Only a limited set of operations are currently recognized. Notably, pointer +// arithmetic, null-pointer assignments and _nullable/_nonnull attributes are +// missing as of yet. +// +//===----------------------------------------------------------------------===// + +#ifndef CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_NULLPOINTERANALYSISMODEL_H +#define CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_NULLPOINTERANALYSISMODEL_H + +#include "clang/AST/ASTContext.h" +#include "clang/AST/Decl.h" +#include "clang/AST/Expr.h" +#include "clang/AST/Stmt.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" +#include "clang/Analysis/CFG.h" +#include "clang/Analysis/FlowSensitive/CFGMatchSwitch.h" +#include "clang/Analysis/FlowSensitive/DataflowAnalysis.h" +#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h" +#include "clang/Analysis/FlowSensitive/DataflowLattice.h" +#include "clang/Analysis/FlowSensitive/MapLattice.h" +#include "clang/Analysis/FlowSensitive/NoopLattice.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/ADT/Twine.h" + +namespace clang::dataflow { + +class NullPointerAnalysisModel + : public DataflowAnalysis<NullPointerAnalysisModel, NoopLattice> { +public: + /// A transparent wrapper around the function arguments of transferBranch(). + /// Does not outlive the call to transferBranch(). + struct TransferArgs { + bool Branch; + Environment &Env; + }; + +private: + CFGMatchSwitch<Environment> TransferMatchSwitch; + ASTMatchSwitch<Stmt, TransferArgs> BranchTransferMatchSwitch; + +public: + explicit NullPointerAnalysisModel(ASTContext &Context); + + static NoopLattice initialElement() { return {}; } + + static ast_matchers::StatementMatcher ptrValueMatcher(); + + // Used to initialize the storage locations of function arguments. + // Required to merge these values within the environment. + void initializeFunctionParameters(const ControlFlowContext &CFCtx, + Environment &Env); + + void transfer(const CFGElement &E, NoopLattice &State, Environment &Env); + + void transferBranch(bool Branch, const Stmt *E, NoopLattice &State, + Environment &Env); + + void join(QualType Type, const Value &Val1, const Environment &Env1, + const Value &Val2, const Environment &Env2, Value &MergedVal, + Environment &MergedEnv) override; + + ComparisonResult compare(QualType Type, const Value &Val1, + const Environment &Env1, const Value &Val2, + const Environment &Env2) override; + + Value *widen(QualType Type, Value &Prev, const Environment &PrevEnv, + Value &Current, Environment &CurrentEnv) override; +}; + +class NullCheckAfterDereferenceDiagnoser { +public: + struct DiagnoseArgs { + llvm::DenseMap<const Value *, const Expr *> &ValToDerefLoc; + llvm::DenseMap<SourceLocation, const Value *> &WarningLocToVal; + const Environment &Env; + }; + + using ResultType = + std::pair<std::vector<SourceLocation>, std::vector<SourceLocation>>; + + // Maps a pointer's Value to a dereference, null-assignment, etc. + // This is used later to construct the Note tag. + llvm::DenseMap<const Value *, const Expr *> ValToDerefLoc; + // Maps Maps a warning's SourceLocation to its relevant Value. + llvm::DenseMap<SourceLocation, const Value *> WarningLocToVal; + ---------------- Discookie wrote:
These maps are used to make the note-tags within `NullCheckAfterDereferenceCheck`. Their naming scheme is a bit misleading in that sense, and note-tags could probably also be created directly by the Diagnoser. https://github.com/llvm/llvm-project/pull/84166 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
