RFR: 8328630: Add logging when needed symbols in dll are missing. [v6]

[Robbin Ehn]

On Tue, 9 Apr 2024 08:49:53 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   use SetLastError to clear error
>
> Thanks for adding this, it's helpful.
> 
> Just some minor comments.

Thanks @Hamlin-Li !

> src/hotspot/os/posix/os_posix.cpp line 720:
> 
>> 718:     // It is possible that we found a NULL symbol, hence no error.
>> 719:     if (tmp != nullptr) {
>> 720:       log_debug(os)("Symbol %s not found in dll: %s", name, tmp);
> 
> Would log_warning be more suitable?

The reason why they are not warning is that we have code that is just checking if a function is available.
E.g. this happens like 40 times for math libs we try load and we don't want 40 warnings on every boot when that.

> src/hotspot/os/windows/os_windows.cpp line 1288:
> 
>> 1286:     char buf[512];
>> 1287:     if (os::lasterror(buf, sizeof(buf)) > 0) {
>> 1288:       log_debug(os)("Symbol %s not found in dll: %s", name, buf);
> 
> similar here.

Same as above! Unfortunately we can't log it as warning, because we do these spectated looks ups.

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PR Comment: https://git.openjdk.org/jdk/pull/18404#issuecomment-2044495757
PR Review Comment: https://git.openjdk.org/jdk/pull/18404#discussion_r1557259616
PR Review Comment: https://git.openjdk.org/jdk/pull/18404#discussion_r1557261308