Implement daedalean-unions-must-not-be-used check

clang-tools-extra/clang-tidy/daedalean/CMakeLists.txt

@@ -23,6 +23,7 @@ add_clang_library(clangTidyDaedaleanModule
   StructsAndClassesCheck.cpp
   ProtectedMustNotBeUsedCheck.cpp
   SwitchStatementCheck.cpp
+  UnionsMustNotBeUsedCheck.cpp
 
   LINK_LIBS
   clangTidy

clang-tools-extra/clang-tidy/daedalean/DaedaleanTidyModule.cpp

@@ -26,6 +26,7 @@
 #include "SwitchStatementCheck.h"
 #include "TernaryOperatorMustNotBeUsedCheck.h"
 #include "TypeConversionsCheck.h"
+#include "UnionsMustNotBeUsedCheck.h"
 
 using namespace clang::ast_matchers;
 
@@ -73,6 +74,8 @@ class DaedaleanModule : public ClangTidyModule {
         "daedalean-ternary-operator-must-not-be-used");
     CheckFactories.registerCheck<SwitchStatementCheck>(
         "daedalean-switch-statement");
+    CheckFactories.registerCheck<UnionsMustNotBeUsedCheck>(
+        "daedalean-unions-must-not-be-used");
   }
 };
 

clang-tools-extra/clang-tidy/daedalean/UnionsMustNotBeUsedCheck.cpp

@@ -0,0 +1,32 @@
+//===--- UnionsMustNotBeUsedCheck.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 "UnionsMustNotBeUsedCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace daedalean {
+
+void UnionsMustNotBeUsedCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(recordDecl(isUnion()).bind("x"), this);
+}
+
+void UnionsMustNotBeUsedCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *MatchedDecl = Result.Nodes.getNodeAs<RecordDecl>("x");
+  diag(MatchedDecl->getLocation(), "Unions must not be used");
+  diag(MatchedDecl->getLocation(), "Remove union %0", DiagnosticIDs::Note)
+      << MatchedDecl;
+}
+
+} // namespace daedalean
+} // namespace tidy
+} // namespace clang

clang-tools-extra/clang-tidy/daedalean/UnionsMustNotBeUsedCheck.h

@@ -0,0 +1,34 @@
+//===--- UnionsMustNotBeUsedCheck.h - clang-tidy ----------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_DAEDALEAN_UNIONSMUSTNOTBEUSEDCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_DAEDALEAN_UNIONSMUSTNOTBEUSEDCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace daedalean {
+
+/// Checks CS.R.29 and flags uses of unions
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/daedalean-unions-must-not-be-used.html
+class UnionsMustNotBeUsedCheck : public ClangTidyCheck {
+public:
+  UnionsMustNotBeUsedCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace daedalean
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_DAEDALEAN_UNIONSMUSTNOTBEUSEDCHECK_H

clang-tools-extra/docs/ReleaseNotes.rst

@@ -250,6 +250,11 @@ New checks
 - New :doc:`daedalean-type-conversions
   <clang-tidy/checks/daedalean-type-conversions>` check.
 
+- New :doc:`daedalean-unions-must-not-be-used
+  <clang-tidy/checks/daedalean-unions-must-not-be-used>` check.
+
+  FIXME: add release notes.
+
 - New :doc:`misc-misleading-bidirectional <clang-tidy/checks/misc-misleading-bidirectional>` check.
 
   Inspects string literal and comments for unterminated bidirectional Unicode

clang-tools-extra/docs/clang-tidy/checks/daedalean-unions-must-not-be-used.rst

@@ -0,0 +1,6 @@
+.. title:: clang-tidy - daedalean-unions-must-not-be-used
+
+daedalean-unions-must-not-be-used
+=================================
+
+Flags uses of unions and warns about them.

clang-tools-extra/docs/clang-tidy/checks/list.rst

@@ -175,7 +175,6 @@ Clang-Tidy Checks
    `daedalean-class-methods <daedalean-class-methods.html>`_,
    `daedalean-derived-classes <daedalean-derived-classes.html>`_, "Yes"
    `daedalean-enum-class <daedalean-enum-class.html>`_, "Yes"
-   `daedalean-type-conversions <daedalean-type-conversions.html>`_, "Yes"
    `daedalean-floating-point-comparison <daedalean-floating-point-comparison.html>`_,
    `daedalean-friend-declarations <daedalean-friend-declarations.html>`_,
    `daedalean-include-order <daedalean-include-order.html>`_, "Yes"
@@ -187,6 +186,8 @@ Clang-Tidy Checks
    `daedalean-structs-and-classes <daedalean-structs-and-classes.html>`_, "Yes"
    `daedalean-switch-statement <daedalean-switch-statement.html>`_,
    `daedalean-ternary-operator-must-not-be-used <daedalean-ternary-operator-must-not-be-used.html>`_,
+   `daedalean-type-conversions <daedalean-type-conversions.html>`_,
+   `daedalean-unions-must-not-be-used <daedalean-unions-must-not-be-used.html>`_, "Yes"
    `darwin-avoid-spinlock <darwin-avoid-spinlock.html>`_,
    `darwin-dispatch-once-nonstatic <darwin-dispatch-once-nonstatic.html>`_, "Yes"
    `fuchsia-default-arguments-calls <fuchsia-default-arguments-calls.html>`_,
@@ -347,6 +348,7 @@ Clang-Tidy Checks
    `readability-use-anyofallof <readability-use-anyofallof.html>`_,
    `zircon-temporary-objects <zircon-temporary-objects.html>`_,
 
+
 .. csv-table:: Aliases..
    :header: "Name", "Redirect", "Offers fixes"
 

clang-tools-extra/test/clang-tidy/checkers/daedalean-unions-must-not-be-used.cpp

@@ -0,0 +1,18 @@
+// RUN: %check_clang_tidy %s daedalean-unions-must-not-be-used %t
+
+union UnionsAreNotOk {
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: Unions must not be used [daedalean-unions-must-not-be-used]
+  // CHECK-MESSAGES: :[[@LINE-2]]:7: note: Remove union 'UnionsAreNotOk'
+  int i;
+  char *ptr;
+};
+
+struct Fine {
+  int i;
+  char *ptr;
+};
+
+class AlsoFine {
+  int i;
+  char *ptr;
+};