1 files changed, 102 insertions, 0 deletions
diff --git a/clang/lib/Sema/UsedDeclVisitor.h b/clang/lib/Sema/UsedDeclVisitor.h
new file mode 100644
index 000000000000..d207e07f451a
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+++ b/clang/lib/Sema/UsedDeclVisitor.h
@@ -0,0 +1,102 @@
+//===- UsedDeclVisitor.h - ODR-used declarations visitor --------*- 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 UsedDeclVisitor, a CRTP class which visits all the
+//  declarations that are ODR-used by an expression or statement.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_SEMA_USEDDECLVISITOR_H
+#define LLVM_CLANG_LIB_SEMA_USEDDECLVISITOR_H
+
+#include "clang/AST/EvaluatedExprVisitor.h"
+#include "clang/Sema/SemaInternal.h"
+
+namespace clang {
+template <class Derived>
+class UsedDeclVisitor : public EvaluatedExprVisitor<Derived> {
+protected:
+  Sema &S;
+
+public:
+  typedef EvaluatedExprVisitor<Derived> Inherited;
+
+  UsedDeclVisitor(Sema &S) : Inherited(S.Context), S(S) {}
+
+  Derived &asImpl() { return *static_cast<Derived *>(this); }
+
+  void VisitDeclRefExpr(DeclRefExpr *E) {
+    auto *D = E->getDecl();
+    if (isa<FunctionDecl>(D) || isa<VarDecl>(D)) {
+      asImpl().visitUsedDecl(E->getLocation(), D);
+    }
+  }
+
+  void VisitMemberExpr(MemberExpr *E) {
+    auto *D = E->getMemberDecl();
+    if (isa<FunctionDecl>(D) || isa<VarDecl>(D)) {
+      asImpl().visitUsedDecl(E->getMemberLoc(), D);
+    }
+    asImpl().Visit(E->getBase());
+  }
+
+  void VisitCapturedStmt(CapturedStmt *Node) {
+    asImpl().visitUsedDecl(Node->getBeginLoc(), Node->getCapturedDecl());
+    Inherited::VisitCapturedStmt(Node);
+  }
+
+  void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
+    asImpl().visitUsedDecl(
+        E->getBeginLoc(),
+        const_cast<CXXDestructorDecl *>(E->getTemporary()->getDestructor()));
+    asImpl().Visit(E->getSubExpr());
+  }
+
+  void VisitCXXNewExpr(CXXNewExpr *E) {
+    if (E->getOperatorNew())
+      asImpl().visitUsedDecl(E->getBeginLoc(), E->getOperatorNew());
+    if (E->getOperatorDelete())
+      asImpl().visitUsedDecl(E->getBeginLoc(), E->getOperatorDelete());
+    Inherited::VisitCXXNewExpr(E);
+  }
+
+  void VisitCXXDeleteExpr(CXXDeleteExpr *E) {
+    if (E->getOperatorDelete())
+      asImpl().visitUsedDecl(E->getBeginLoc(), E->getOperatorDelete());
+    QualType Destroyed = S.Context.getBaseElementType(E->getDestroyedType());
+    if (const RecordType *DestroyedRec = Destroyed->getAs<RecordType>()) {
+      CXXRecordDecl *Record = cast<CXXRecordDecl>(DestroyedRec->getDecl());
+      asImpl().visitUsedDecl(E->getBeginLoc(), S.LookupDestructor(Record));
+    }
+
+    Inherited::VisitCXXDeleteExpr(E);
+  }
+
+  void VisitCXXConstructExpr(CXXConstructExpr *E) {
+    asImpl().visitUsedDecl(E->getBeginLoc(), E->getConstructor());
+    Inherited::VisitCXXConstructExpr(E);
+  }
+
+  void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) {
+    asImpl().Visit(E->getExpr());
+  }
+
+  void visitUsedDecl(SourceLocation Loc, Decl *D) {
+    if (auto *CD = dyn_cast<CapturedDecl>(D)) {
+      if (auto *S = CD->getBody()) {
+        asImpl().Visit(S);
+      }
+    } else if (auto *CD = dyn_cast<BlockDecl>(D)) {
+      if (auto *S = CD->getBody()) {
+        asImpl().Visit(S);
+      }
+    }
+  }
+};
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_SEMA_USEDDECLVISITOR_H