Capture unresolved backtraces on traps #4193
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I was running tests recently and was surprised that the `--test all` test was taking more than a minute to run when I didn't recall it ever taking more than a minute historically. A bisection pointed out bytecodealliance#4183 as the cause and after re-reviewing I realized I forgot that we capture unresolved backtraces by default (and don't actually resolve them anywhere yet but that's a problem for another day) rather than resolved backtraces. This means that it's intended that we use `Backtrace::new_unresolved` instead of `Backtrace::new` in the traphandlers crate. The reason that tests were running so slowly is that the tests which deal with deep stacks (e.g. stack overflow) would take forever in testing as the Rust-based decoding of DWARF information is egregiously slow in unoptimized mode. I did discover independently that optimizing these dependencies makes the tests ~6x faster, but that's irrelevant if we're not symbolicating in the first place.
pchickey
approved these changes
May 31, 2022
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I was running tests recently and was surprised that the
--test alltest was taking more than a minute to run when I didn't recall it ever
taking more than a minute historically. A bisection pointed out #4183 as
the cause and after re-reviewing I realized I forgot that we capture
unresolved backtraces by default (and don't actually resolve them
anywhere yet but that's a problem for another day) rather than resolved
backtraces. This means that it's intended that we use
Backtrace::new_unresolvedinstead ofBacktrace::newin thetraphandlers crate.
The reason that tests were running so slowly is that the tests which
deal with deep stacks (e.g. stack overflow) would take forever in
testing as the Rust-based decoding of DWARF information is egregiously
slow in unoptimized mode. I did discover independently that optimizing
these dependencies makes the tests ~6x faster, but that's irrelevant if
we're not symbolicating in the first place.