RFR: 8304089: Convert TraceDependencies to UL [v3]

[David Holmes]

On Thu, 16 Mar 2023 13:16:42 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Sorry I don't follow that. `use_vm_log()` only affects non-product builds and forces `LogVMOutput` to true. That in turn will cause `defaultStream::init_log()` to execute which initializes the log file etc. But I don't see how that would cause UL logging for "dependencies" to also get written to the log file???
>
> See the function log_dependency()
> 
> https://github.com/openjdk/jdk/blob/421b4ee33c652cc7c444fbbf298bbc23d052c2fe/src/hotspot/share/code/dependencies.cpp#L845
> 
> called from here (as one place).
> 
> https://github.com/openjdk/jdk/blob/421b4ee33c652cc7c444fbbf298bbc23d052c2fe/src/hotspot/share/code/dependencies.cpp#L2071
> 
> When TraceDependencies was true, the log file would be non-null and log_dependency would write to it.  Keeping this with -Xlog:dependencies=debug retains what TraceDependencies did.

Hmmm this seems broken to me then. We output the general dependency logging to one place based on UL configuration, but then we output `log_dependency` to the log file. If these are meant to be related and always reported together then we have lost that. If they are actually unrelated then this may still need the TraceDependencies flag to control it.

@iwanowww can you comment on this please?

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PR: https://git.openjdk.org/jdk/pull/13007