Add lazy_static macro #125
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This adds the `lazy_static!` macro from the `lazy_static` crate. We need to re-implement it both since it establishes causality (through its use of `Once`), and because the state needs to be cleared on every execution. This implementation does that. One unfortunate downside of this implementation is that it is inherently unsafe. Specifically, in the context of loom, statics are, well, not static. And yet the API of `lazy_static!` is such that it gives out `'static` references. We _cannot_ safely give out `'static` refs into statics that we clear on every execution. One option here is to leak every static we allocate. The code would then be safe (since the references would indeed be `'static`), but it would mean we leak _all_ statics for _every_ execution, no matter whether the user needs them to be `'static` or not. Fixes tokio-rs#124.
jonhoo
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Apr 12, 2020
With this change, loom runs to completion on the treiber test!
I ran it with `LOOM_MAX_PREEMPTIONS=3`, and it took _forever_ (well, it
took 2h), but eventually finished with:
================== Iteration 112280000 ==================
Completed in 112291514 iterations
ok
With `LOOM_MAX_PREEMPTIONS=2` it "only" took 13 minutes, and finished
with:
================== Iteration 9680000 ==================
Completed in 9690926 iterations
ok
I updated the CI script to run with `LOOM_MAX_PREEMPTIONS=2`.
Note that this change depends on
tokio-rs/loom#125 and
tokio-rs/loom#128. The `patch` in the root
`Cargo.toml` should be removed once a new loom release is made.
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This adds the
lazy_static!macro from thelazy_staticcrate. We needto re-implement it both since it establishes causality (through its use
of
Once), and because the state needs to be cleared on everyexecution. This implementation does that.
One unfortunate downside of this implementation is that it is inherently
unsafe. Specifically, in the context of loom, statics are, well, not
static. And yet the API of
lazy_static!is such that it gives out'staticreferences. We cannot safely give out'staticrefs intostatics that we clear on every execution.
One option here is to leak every static we allocate. The code would then
be safe (since the references would indeed be
'static), but it wouldmean we leak all statics for every execution, no matter whether the
user needs them to be
'staticor not.Fixes #124.