Client UUID appears truncated in verbose log

[mpirvu]

Under -Xjit:verbose={JITServer} the client prints its UUID in the verbose log, but it appears truncated:
#JITServer: Identifier for current client JVM: 3663742628
while it should have been like this:
#JITServer: Identifier for current client JVM: 9388384503642212004

The line that prints the UUID is like this:

         TR_VerboseLog::writeLineLocked(TR_Vlog_JITServer, "Identifier for current client JVM: %" OMR_PRIu64 "\n",
               compInfo->getPersistentInfo()->getClientUID());

It seems that OMR_PRIu64 does not play nice with the verbose log. I replaced that with PRIu64 and got the same bad result. "%llu" on the other hand prints the correct value.
Note that if I use fprintf instead of TR_VerboseLog::writeLineLocked then everything is fine, so it's just the combination of verbose log and OMR_PRIu64 that misbehaves.

[dmitry-ten]

The reason it doesn't work correctly is due to verbose log using a custom print function implemented in OMR and it not being compatible with PRI format specifiers.
OMR_PRIu64 is equivalent to PRIu64 macro, which converts to %lu on a Ubuntu 64-bit machine.
The standard library print functions handle this format specifier correctly, i.e. given a 64-bit value, print out all the bits.
However, the OMR implementation (in omrstr.c) only considers the value to be 64-bit, if the %llu specifier is used, as can be seen here:
https://github.com/eclipse/omr/blob/465d74a8668dd1ec3a726944a6ffd53d3548cf23/port/common/omrstr.c#L660-L667

I verified that if we change line 665 to always assign J9FTYPE_U64 type, then the correct client id is printed.

Fixing how printing works in OMR, for all platforms, seems like a pretty difficult task. For now, I'll just explicitly use %llu specifier instead of OMR_PRIu64.

[mpirvu]

Resolved by #10209