[clang-tools-extra] [clang-tidy] Create bugprone-incorrect-enable-shared-from-this check (PR #102299)

[Julian Schmidt via cfe-commits]

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@@ -0,0 +1,105 @@
+//===--- IncorrectEnableSharedFromThisCheck.cpp - clang-tidy --------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "IncorrectEnableSharedFromThisCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Basic/Specifiers.h"
+#include "llvm/ADT/SmallPtrSet.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+void IncorrectEnableSharedFromThisCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(translationUnitDecl(), this);
+}
+
+void IncorrectEnableSharedFromThisCheck::check(
+    const MatchFinder::MatchResult &Result) {
+
+  class Visitor : public RecursiveASTVisitor<Visitor> {
+    IncorrectEnableSharedFromThisCheck &Check;
+    llvm::SmallPtrSet<const CXXRecordDecl *, 16> EnableSharedClassSet;
+
+  public:
+    explicit Visitor(IncorrectEnableSharedFromThisCheck &Check)
+        : Check(Check) {}
+
+    bool VisitCXXRecordDecl(CXXRecordDecl *RDecl) {
+      if (!RDecl->hasDefinition()) {
+        return true;
+      }
+
+      if (isStdEnableSharedFromThis(RDecl))
+        EnableSharedClassSet.insert(RDecl->getCanonicalDecl());
+
+      for (const auto &Base : RDecl->bases()) {
+        const auto *BaseRecord =
+            Base.getType()->getAsCXXRecordDecl()->getCanonicalDecl();
+
+        if (EnableSharedClassSet.contains(BaseRecord) ||
+            isStdEnableSharedFromThis(BaseRecord)) {
+
+          if (isStdEnableSharedFromThis(BaseRecord) &&
+              Base.getAccessSpecifier() != clang::AS_public) {
----------------
5chmidti wrote:

You are calling `isStdEnableSharedFromThis(BaseRecord)` twice with the same value. Please save the result before the `if` and reuse the computed value (yes, it's a cheap computation).

https://github.com/llvm/llvm-project/pull/102299