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

[Gábor Horváth 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
+    UnmodeledExprKind,
+    LoopWideningKind,
+    BEGIN_UNMODELED_STMT = UnmodeledExprKind,
+    END_UNMODELED_STMT = LoopWideningKind,
+  };
+
+  Kind getKind() const { return K; }
+
+  virtual void Profile(llvm::FoldingSetNodeID &ID) const = 0;
+  virtual void dumpToStream(raw_ostream &OS) const = 0;
+
+  LLVM_DUMP_METHOD void dump() const;
+
+protected:
+  explicit InvalidationCause(Kind K) : K(K) {}
+  virtual void anchor();
+
+private:
+  Kind K;
+};
+
+/// Abstract base for invalidations triggered by an unmodeled or partially
+/// modeled call.
+class UnmodeledCall : public InvalidationCause {
+public:
+  /// Returns the expression whose value will be the result of this call.
+  /// Null if and only if 'this' is a CXXDestructorCall.
+  const CallExpr *getCallExpr() const { return CE; }
+
+  static bool classof(const InvalidationCause *C) {
+    return C->getKind() >= BEGIN_UNMODELED_CALL &&
+           C->getKind() <= END_UNMODELED_CALL;
+  }
+
+protected:
+  const CallExpr *CE;
+  UnmodeledCall(Kind K, const CallExpr *CE) : InvalidationCause(K), CE(CE) {}
+  void anchor() override;
+};
+
+/// Conservative evaluation of a call: the call's body wasn't inlined and we
+/// fall back to invalidating its arguments / reachable globals.
+class ConservativeEvalCall final : public UnmodeledCall {
+public:
+  void Profile(llvm::FoldingSetNodeID &ID) const override { Profile(ID, CE); }
+
+  static void Profile(llvm::FoldingSetNodeID &ID, const CallExpr *CE) {
+    ID.AddInteger((unsigned)ConservativeEvalCallKind);
+    ID.AddPointer(CE);
+  }
+
+  void dumpToStream(raw_ostream &OS) const override;
+
+  static bool classof(const InvalidationCause *C) {
+    return C->getKind() == ConservativeEvalCallKind;
+  }
+
+protected:
+  friend class SymbolManager;
+  explicit ConservativeEvalCall(const CallExpr *CE)
+      : UnmodeledCall(ConservativeEvalCallKind, CE) {}
+  void anchor() override;
+};
+
+/// A call that the analyzer models but bails out of for some operands (e.g.
+/// CStringChecker's memcpy fallback, MallocChecker's free invalidation,
+/// SmartPtrModeling's ostream<< handling).
+class PartiallyModeledCall final : public UnmodeledCall {
----------------
Xazax-hun wrote:

Does a new base class carry its weight if it adds no extra information other than its kind? Or should we just have a field for the unmodeled call for now?

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