[clang-tools-extra] [clang-tidy] Added bugprone-exception-rethrow check (PR #86448)

[Julian Schmidt via cfe-commits]

================
@@ -0,0 +1,67 @@
+//===--- ExceptionRethrowCheck.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 "ExceptionRethrowCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+void ExceptionRethrowCheck::registerMatchers(MatchFinder *Finder) {
+
+  auto RefToExceptionVariable = declRefExpr(to(varDecl(isExceptionVariable())));
+  auto StdMoveCall =
+      callExpr(argumentCountIs(1), callee(functionDecl(hasName("::std::move"))),
+               hasArgument(0, RefToExceptionVariable));
+  auto CopyOrMoveConstruction = cxxConstructExpr(
+      argumentCountIs(1),
+      traverse(TK_AsIs, hasDeclaration(cxxConstructorDecl(
+                            anyOf(isCopyConstructor(), isMoveConstructor())))),
+      hasArgument(0, anyOf(RefToExceptionVariable, StdMoveCall)));
+
+  auto HasEmptyThrowExprDescendant =
+      hasDescendant(cxxThrowExpr(equalsBoundNode("empty-throw")));
+
+  Finder->addMatcher(
+      cxxThrowExpr(
+          unless(isExpansionInSystemHeader()), unless(has(expr())),
+          expr().bind("empty-throw"),
+          anyOf(unless(hasAncestor(cxxCatchStmt())),
+                hasAncestor(cxxCatchStmt(anyOf(
+                    hasDescendant(functionDecl(HasEmptyThrowExprDescendant)),
+                    hasDescendant(lambdaExpr(HasEmptyThrowExprDescendant))))))),
+      this);
+  Finder->addMatcher(
+      cxxThrowExpr(unless(isExpansionInSystemHeader()),
+                   has(expr(anyOf(RefToExceptionVariable, StdMoveCall,
+                                  CopyOrMoveConstruction))))
+          .bind("throw"),
+      this);
+}
+
+void ExceptionRethrowCheck::check(const MatchFinder::MatchResult &Result) {
+  if (const auto *MatchedThrow =
+          Result.Nodes.getNodeAs<CXXThrowExpr>("throw")) {
+    const Expr *ThrownObject = MatchedThrow->getSubExpr();
+    diag(MatchedThrow->getThrowLoc(),
+         "throwing a copy of the caught %0 exception, remove the argument to "
+         "throw the original exception object")
+        << ThrownObject->getType().getNonReferenceType();
----------------
5chmidti wrote:

Ah, ok.

https://github.com/llvm/llvm-project/pull/86448