[clang-tidy] llvm-header-guard suggest invalid ifdef macros name

[vbvictor]

When https://clang.llvm.org/extra/clang-tidy/checks/llvm/header-guard.html check sees a file with has "llvm" inside its filepath (e.g. clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h), instead of making such ifdef:

#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADERGUARDCHECK_H

The check makes:

#ifndef LLVM_HEADERGUARDCHECK_H

The check removes leading part if sees "LLVM" in check-name which is incorrect.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Baranov Victor (vbvictor)

When https://clang.llvm.org/extra/clang-tidy/checks/llvm/header-guard.html check sees a file with has "llvm" inside its filepath (e.g. `clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h`), instead of making such `ifdef`: ```cpp #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADERGUARDCHECK_H ``` The check makes: ```cpp #ifndef LLVM_HEADERGUARDCHECK_H ```

The check removes leading part if sees "LLVM" in check-name which is incorrect.

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor is working on this issue. If someone is assigned to the issue or claimed to be working on it, ping the person. After one week without a response, the assignee may be changed.
2. Leave a comment indicating that you are working on the issue, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Baranov Victor (vbvictor)

When https://clang.llvm.org/extra/clang-tidy/checks/llvm/header-guard.html check sees a file with has "llvm" inside its filepath (e.g. `clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h`), instead of making such `ifdef`: ```cpp #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADERGUARDCHECK_H ``` The check makes: ```cpp #ifndef LLVM_HEADERGUARDCHECK_H ```

The check removes leading part if sees "LLVM" in check-name which is incorrect.

[sathvikreddy853]

Hey @vbvictor, I would like to work on this issue.

[vbvictor]

@sathvikreddy853 sure, but we have to think careful though.
It seems to me that we should have one "llvm" name for ifdef if we are under "one after another llvm dirs" like this: llvm/include/llvm/ADT/ArrayRef.h (the result is arguably expected to be LLVM_ADT_ARRAYREF_H, not LLVM_LLVM_ADT_ARRAYREF_H).

But if we have clang-tools-extra/clang-tidy/llvm/HeaderGuardCheck.h we don't have "llvm" directories one after another, thus the result should be LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_HEADERGUARDCHECK_H

[LegalizeAdulthood]

I see why some folks decide to put a GUID in their header guards :)

[vbvictor]

I see why some folks decide to put a GUID in their header guards :)

Just use #pragma once :)