Run rustc for information fewer times
#5249
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r? @matklad (rust_highfive has picked a reviewer for you, use r? to override) |
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Hm, interesting, so the previous logic kinda handled this in the case where target was not passed at all....
Perhaps add a helper Context::is_cross_compiling which handles both "no target" and "explicit target the same as the host", so that we don't duplicated this logic incorrectly elsewhere?
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I'm gonna hold off on this suggestion for now because the deduction here is different than Cargo's historical deduction of "am I cross compiling?" (aka is --target passed?). I'd hope though we could improve this in the future!
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Oh, actually this side-effectual mutating API looks horrible to me :) Do you feel like refactoring it to
self.host_info = self.probe_target_info_kind(Kind::Host);
self.target_info = if host_target_same {
self.host_info.clone()
} else {
self.probe_target_info_kind(Kind::Target)
}?
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Hm, what about normalizing and will build everything twice, because the command line and thus the fingerprints would differ. |
Currently if you pass `--target` the same as rustc's host Cargo will run `rustc` on extra time to learn information, but we only need to run it once to learn such information!
alexcrichton
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Updated! Leaving out the normalization for now as I think it runs the risk for breakage, but we can fix that later for sure I think. |
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@bors r+ |
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📌 Commit 0eb7edf has been approved by |
Run `rustc` for information fewer times Currently if you pass `--target` the same as rustc's host Cargo will run `rustc` on extra time to learn information, but we only need to run it once to learn such information!
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☀️ Test successful - status-appveyor, status-travis |
One hard cs problem Closes #5313 r? @alexcrichton Note that, due to the first commit, this still gives us all the benefits of #5249: if RUSTFLAGS is empty, we will run only a single rustc process, even if we can't cache it across different cargo invocations.
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Currently if you pass
--targetthe same as rustc's host Cargo will runrustcon extra time to learn information, but we only need to run it once to learn
such information!