[clang] [analyzer] Introduce the invalidation artifact symbol (PR #207155)

[Balázs Benics via cfe-commits]

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+//===- InvalidationCause.h - Cause of a region invalidation ------*- 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 InvalidationCause, a small class hierarchy describing why
+// a memory region was invalidated by ProgramState::invalidateRegions. The
+// cause is carried by SymbolInvalidationArtifact symbols so that downstream
+// machinery (bug-report suppression, diagnostics) can distinguish symbolic
+// values produced by an invalidation event from ordinary conjured symbols.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_INVALIDATIONCAUSE_H
+#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_INVALIDATIONCAUSE_H
+
+#include "clang/Basic/LLVM.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/Compiler.h"
+
+namespace clang {
+
+class CallExpr;
+class Stmt;
+
+namespace ento {
+
+class SymbolManager;
+
+/// Describes why a memory region was invalidated. Instances are uniqued by
+/// SymbolManager::acquireCause<T>(...) and are stable for the analysis
+/// lifetime; callers must not allocate them on the stack.
+class InvalidationCause : public llvm::FoldingSetNode {
+public:
+  virtual ~InvalidationCause() = default;
+
+  enum Kind {
+    // UnmodeledCall range
+    ConservativeEvalCallKind,
+    PartiallyModeledCallKind,
+    BEGIN_UNMODELED_CALL = ConservativeEvalCallKind,
+    END_UNMODELED_CALL = PartiallyModeledCallKind,
+
+    // UnmodeledStmt range
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steakhal wrote:

I'll keep this in mind and revisit this when applicable.

https://github.com/llvm/llvm-project/pull/207155