Currently, the Unified Logging framework defaults to three decorators (uptime, level, tags) whenever the user does not specify otherwise through -Xlog. This can result in cumbersome input whenever a specific user that relies on a particular tag(s) has some predefined needs. For example, C2 developers rarely need decorations, and having to manually specify this every time results inconvenient.

To address this, this ticket enables the possibility of adding tag-specific default decorators to UL. These defaults are in no way overriding user input -- they will only act whenever -Xlog has no decorators supplied and there is a positive match with the pre-specified defaults. Such a match is based on the following:

    Inclusion: if -Xlog:jit+compilation is provided, a default for jit may be applied.
    Specificity: if, for the above line, there is a more specific default for jit+compilation the latter shall be applied. Upon equal specificity cases, both defaults will be applied.
    Additionally, defaults may target a specific log level.

Decorators are also associated with an output file, so an output device may only have one set of decorators. For this reason, if different LogSelections trigger defaults, none is to be applied.

In summary, these defaults may be seen as a "tailored" or "flavoured" version of the existing "uptime-level-tags" current defaults.