[clang-tools-extra] [clang-tidy] Add new check: `modernize-use-concise-preprocessor-directives` (PR #146830)

[via cfe-commits]

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@@ -0,0 +1,105 @@
+//===--- UseConcisePreprocessorDirectivesCheck.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 "UseConcisePreprocessorDirectivesCheck.h"
+#include "clang/Basic/TokenKinds.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Lex/PPCallbacks.h"
+#include "clang/Lex/Preprocessor.h"
+
+namespace clang::tidy::modernize {
+
+namespace {
+
+class IfPreprocessorCallbacks final : public PPCallbacks {
+public:
+  IfPreprocessorCallbacks(ClangTidyCheck &Check, Preprocessor &PP)
+      : Check(Check), PP(PP) {}
+
+  void If(SourceLocation Loc, SourceRange ConditionRange,
+          ConditionValueKind) override {
+    impl(Loc, ConditionRange, {"ifdef", "ifndef"});
+  }
+
+  void Elif(SourceLocation Loc, SourceRange ConditionRange, ConditionValueKind,
+            SourceLocation) override {
+    if (PP.getLangOpts().C23 || PP.getLangOpts().CPlusPlus23) {
+      impl(Loc, ConditionRange, {"elifdef", "elifndef"});
+    }
+  }
+
+private:
+  void impl(SourceLocation DirectiveLoc, SourceRange ConditionRange,
+            const llvm::StringLiteral (&Replacements)[2]) {
+    StringRef Condition =
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EugeneZelenko wrote:

Should be `const`. Same for some other variables.

https://github.com/llvm/llvm-project/pull/146830