RFR: 8017234: Hotspot should stop using mapfiles [v6]

[Julian Waters]

On Thu, 22 Feb 2024 15:26:34 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> I see, seems like it's an unfortunate situation where a fix is hard or even impossible. If we file a gcc bug for it now, it'll get fixed in some insanely new gcc version (such as gcc 15 or 16) and we'd have to jump to that version, which I'm sure no one is going to like :(
>> 
>> Nevertheless, since there are so many instances of it, I suggest #pragma GCC visibility push(hidden) instead of adding a new macro to this file, in my opinion it's somewhat cleaner and also makes the change smaller.
>> 
>> #pragma GCC visibility push(hidden)
>> // Junk that needs hidden visibility to work properly
>> #pragma GCC visibility pop
>> 
>> Also, why TARGET_COMPILER_gcc instead of __GNUC__? Does this have to work with Apple Clang on macOS as well?
>
> This is not an issue with clang, only gcc.
> 
> My understanding was that the proper way to test for compiler in Hotspot code was by using `TARGET_COMPILER_gcc`.
> 
> I can try using the `#pragma` route instead; if it works I agree it is slightly better than to sprinkle `HIDDEN` all over the place.

Drat, I thought the pragma would work. Sorry.

I would file a bug for gcc, but I have no idea what to even describe it as

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PR Review Comment: https://git.openjdk.org/jdk/pull/17955#discussion_r1500624847