Alp Mestanogullari authored Sep 07, 2019 and Marge Bot committed Sep 19, 2019

'withTiming' becomes a function that, when passed '-vN' (N >= 2) or
'-ddump-timings', will print timing (and possibly allocations) related
information. When additionally built with '-eventlog' and executed with
'+RTS -l', 'withTiming' will also emit both 'traceMarker' and 'traceEvent'
events to the eventlog.

'withTimingSilent' on the other hand will never print any timing information,
under any circumstance, and will only emit 'traceEvent' events to the eventlog.
As pointed out in !1672, 'traceMarker' is better suited for things that we
might want to visualize in tools like eventlog2html, while 'traceEvent'
is better suited for internal events that occur a lot more often and that we
don't necessarily want to visualize.

This addresses #17138 by using 'withTimingSilent' for all the codegen bits
that are expressed as a bunch of small computations over streams of codegen
ASTs.