[clang] [NFC][LifetimeSafety]: Track assignment history within a single CFGBlock (PR #196075)

[Utkarsh Saxena via cfe-commits]

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@@ -0,0 +1,36 @@
+//===- AssignmentQuery.cpp - C++ Lifetime Safety Checker --------*- 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 functions for tracing assignment history,
+// as well as future data structures or other helper functions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_ASSIGNMENTQUERY_H
+#define LLVM_CLANG_ANALYSIS_ANALYSES_ASSIGNMENTQUERY_H
+
+#include "clang/Analysis/Analyses/LifetimeSafety/Facts.h"
+#include "clang/Analysis/Analyses/LifetimeSafety/LoanPropagation.h"
+
+namespace clang::lifetimes::internal {
+
+using AssignmentUnit = Origin;
+
+/// Traces the provenance of a pointer to provide contextual notes for
+/// lifetime-related diagnostics.
+///
+/// To help user understand the data flow, we track where the problematic
+/// address originated.
+void trackAssignmentHistory(
+    const FactManager &FactMgr, const LoanPropagationAnalysis &LoanPropagation,
+    llvm::SmallVectorImpl<AssignmentUnit> &AssignmentList,
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usx95 wrote:

Let us have this as the explicit return type since there is only one output.

https://github.com/llvm/llvm-project/pull/196075