Heads up: output of time-passes changing


If you’re parsing the output of running the compiler with -Ztime-passes, then you should be aware that the output is changing with this PR.

Previously the output looked like:

time: 0.034    translation

On Linux, and assuming there are no errors finding the memory use, it will now look like:

time: 0.034; rss: 83MB    translation

On non-Linux, or if there are problems, it will look like it used to.

The extra data is the resident set size, a crude but useful measure of memory used by the compiler. Note that it is the size of the resident set at the end of the phase, and is not the memory used only by that phase.