[clang] [llvm] [LifetimeSafety] Reorganize code into modular components (PR #162474)

[Utkarsh Saxena via llvm-commits]

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@@ -0,0 +1,190 @@
+//===- Dataflow.h - Generic Dataflow Analysis Framework --------*- 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, policy-based driver for dataflow analyses.
+// It provides a flexible framework that combines the dataflow runner and
+// transfer functions, allowing derived classes to implement specific analyses
+// by defining their lattice, join, and transfer functions.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_LIFETIMESAFETY_DATAFLOW_H
+#define LLVM_CLANG_ANALYSIS_ANALYSES_LIFETIMESAFETY_DATAFLOW_H
+
+#include "clang/Analysis/Analyses/LifetimeSafety/Facts.h"
+#include "clang/Analysis/AnalysisDeclContext.h"
+#include "clang/Analysis/CFG.h"
+#include "clang/Analysis/FlowSensitive/DataflowWorklist.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/TimeProfiler.h"
+#include <optional>
+
+namespace clang::lifetimes {
+namespace internal {
+
+enum class Direction { Forward, Backward };
+
+/// A `ProgramPoint` identifies a location in the CFG by pointing to a specific
+/// `Fact`. identified by a lifetime-related event (`Fact`).
+///
+/// A `ProgramPoint` has "after" semantics: it represents the location
+/// immediately after its corresponding `Fact`.
+using ProgramPoint = const Fact *;
+
+/// A generic, policy-based driver for dataflow analyses. It combines
+/// the dataflow runner and the transferer logic into a single class hierarchy.
+///
+/// The derived class is expected to provide:
+/// - A `Lattice` type.
+/// - `StringRef getAnalysisName() const`
+/// - `Lattice getInitialState();` The initial state of the analysis.
+/// - `Lattice join(Lattice, Lattice);` Merges states from multiple CFG paths.
+/// - `Lattice transfer(Lattice, const FactType&);` Defines how a single
+///   lifetime-relevant `Fact` transforms the lattice state. Only overloads
+///   for facts relevant to the analysis need to be implemented.
+///
+/// \tparam Derived The CRTP derived class that implements the specific
+/// analysis.
+/// \tparam LatticeType The dataflow lattice used by the analysis.
+/// \tparam Dir The direction of the analysis (Forward or Backward).
+/// TODO: Maybe use the dataflow framework! The framework might need changes
+/// to support the current comparison done at block-entry.
+template <typename Derived, typename LatticeType, Direction Dir>
+class DataflowAnalysis {
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usx95 wrote:

Moved to `lib`. Thanks for the suggestion.

https://github.com/llvm/llvm-project/pull/162474