FieldDecl::getBitWidthValue api change

[lcarlier]

Hello,

I'm the author of a tool which uses libclang.

My tool doesn't compile anymore because of the following pull request.

#117732

The function FieldDecl::getBitWidthValue has changed. Before it was taking a reference to a const ASTContext &Ctx now it does not.

I still would like to be able to compile my tools against earlier versions of libclang?

How to do? Is there any define or variable I can check at compile time? e.g. on the libclang version?
I see that CINDEX_VERSION_MINOR hasn't been updated for a while....

Kind regards,

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Laurent Carlier (lcarlier)

Hello,

I'm the author of a tool which uses libclang.

My tool doesn't compile anymore because of the following pull request.

#117732

The function FieldDecl::getBitWidthValue has changed. Before it was taking a reference to a const ASTContext &Ctx now it does not.

I still would like to be able to compile my tools against earlier versions of libclang?

How to do? Is there any define or variable I can check at compile time? e.g. on the libclang version?
I see that CINDEX_VERSION_MINOR hasn't been updated for a while....

Kind regards,

[shafik]

CC @AaronBallman @erichkeane

[tbaederr]

I still would like to be able to compile my tools against earlier versions of libclang?

You'll either have to check the version of libclang you're compiling against and pass that information on to your build process, or check the version of clang you're compiling with, e.g. __clang_major__: https://clang.llvm.org/docs/LanguageExtensions.html#builtin-macros and decide using that.

[AaronBallman]

Hello,

I'm the author of a tool which uses libclang.

My tool doesn't compile anymore because of the following pull request.

#117732

The function FieldDecl::getBitWidthValue has changed. Before it was taking a reference to a const ASTContext &Ctx now it does not.

I still would like to be able to compile my tools against earlier versions of libclang?

How to do? Is there any define or variable I can check at compile time? e.g. on the libclang version? I see that CINDEX_VERSION_MINOR hasn't been updated for a while....

libclang is the stable C interface; those APIs should not change. But the C++ APIs are subject to change and so this kind of breakage is expected. The suggestion from @tbaederr is likely your best bet.

[lcarlier]

Ok I'll add an extra -DLIBCLANG_MAJOR_VERSION=x in my builds and take actions based on an #ifdef

Any advice on the best way to detect which libclang version I'm compiling against? My project is using Cmake.

Also can we confirm from which version the api changes? Is it correct this is from libclang major version 20 onwards?

Many thanks.

[AaronBallman]

Any advice on the best way to detect which libclang version I'm compiling against? My project is using Cmake.

CLANG_VERSION_MAJOR and CLANG_VERSION_MINOR are likely good candidates to look at.

Also can we confirm from which version the api changes? Is it correct this is from libclang major version 20 onwards?

Correct, should be Clang 20.x and later.