On Mon, 12 Dec 2022 05:51:52 GMT, Justin King <jck...@openjdk.org> wrote:
>> src/java.base/share/native/launcher/main.c line 37:
>>
>>> 35: #include "jni.h"
>>> 36:
>>> 37: #ifdef UNDEFINED_BEHAVIOR_SANITIZER
>>
>> I really do not like having to make source code changes to accommodate these
>> kinds of tools.
>
> Yeah, it is unfortunate. However there is no other way to actually set the
> defaults nicely. The other alternative is to use environment variables, but
> they are easy to forget when invoking the launcher manually.
Does the env-var override the src declaration, or the other way around?
>> src/java.base/share/native/launcher/main.c line 40:
>>
>>> 38: // Override weak symbol exposed by UBSan to override default options.
>>> This is called by UBSan
>>> 39: // extremely early during library loading, before main is called.
>>> 40: JNIEXPORT const char* __ubsan_default_options() {
>>
>> Why would this need `JNIEXPORT`? This is not a JNI function.
>
> Ugh, apparently resolving doesn't add the comment. I thought it did...
>
> So answering, JNIEXPORT is needed so that the symbol is exported and the
> linker doesn't remove it. It adds `__attribute__((visibility("default"))`.
Okay. The limited documentation on these `___xxx_default_options` functions
didn't show the need for any export/visibility attributes.
-------------
PR: https://git.openjdk.org/jdk/pull/11604
