[clang-tools-extra] [clang-tidy] Add avoid-pragma-once. (PR #140388)

[Baranov Victor via cfe-commits]

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@@ -0,0 +1,50 @@
+//===--- AvoidPragmaOnceCheck.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 "AvoidPragmaOnceCheck.h"
+
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/PPCallbacks.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace clang::tidy::portability {
+
+class PragmaOnceCallbacks : public PPCallbacks {
+public:
+  PragmaOnceCallbacks(AvoidPragmaOnceCheck *Check, const SourceManager &SM)
+      : Check(Check), SM(SM) {}
+  void PragmaDirective(SourceLocation Loc,
+                       PragmaIntroducerKind Introducer) override {
+    auto Str = llvm::StringRef(SM.getCharacterData(Loc));
+    if (!Str.consume_front("#")) {
+      return;
+    }
+    Str = Str.trim();
+    if (!Str.consume_front("pragma")) {
+      return;
+    }
+    Str = Str.trim();
+    if (Str.starts_with("once")) {
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vbvictor wrote:

ditto

https://github.com/llvm/llvm-project/pull/140388