std: A few code size optimizations #12616
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| // LLVM doesn't tend to inline this, presumably because begin_unwind_fmt | ||
| // is #[cold] and #[inline(never)] and because this is flagged as cold | ||
| // as returning !. We really do want this to be inlined, however, | ||
| // because it's just a tiny wrapper. Small wins (~7K) were seen when |
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7K out of? (These numbers are more useful if they have percentages with them too)
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Nice wins! r=me addressing my comments, seems the travis failures might be related? |
This is a ubiquitous type in concurrent code, and the assertions are causing significant code bloat for simple operations such as reading the pointer (injecting a failure point, etc). I am testing executable sizes with no I/O implementations (everything stubbed out to return nothing), and this took the size of a libnative executable from 328K to 207K (37% reduction in size), so I think that this is one assertion that's well worth configuring off for now.
Most of these are unnecessary because we're only looking at static strings. This also moves to Vec in a few places instead of ~[T]. This didn't end up getting much of a code size win (update_log_settings is the third largest function in the executables I'm looking at), but this seems like a generally nice improvement regardless.
This removes all usage of Poly in format strings from libstd. This doesn't prevent more future strings from coming in, but it at least removes the ones for now.
This function is a tiny wrapper that LLVM doesn't want to inline, and it ends up causing more bloat than necessary. The bloat is pretty small, but it's a win of at least 7k for small executables, and I imagine that the number goes up as there are more calls to fail!().
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I've been playing around with code size when linking to libstd recently, and these were some findings I found that really helped code size. I started out by eliminating all I/O implementations from libnative and instead just return an unimplemented error.
In doing so, a `fn main() {}` executable was ~378K before this patch, and about 170K after the patch. These size wins are all pretty minor, but they all seemed pretty reasonable to me. With native I/O not stubbed out, this takes the size of an LTO executable from 675K to 400K.
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Minor or not, getting |
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Correct target_feature completion I changed the `target_feature` to match the description given in rust-lang#12616.
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avoid an ICE in `ptr_as_ptr` when getting the def_id of a local Fixes rust-lang#12616 `Res::def_id` can panic, so avoid calling it in favor of `opt_def_id`, so we can gracefully handle resolutions that don't have a `DefId` (e.g. local variables) and get a false negative in the worst case, rather than an ICE changelog: Fix ICE in [`ptr_as_ptr`] when the cast expression is a function call to a local variable
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avoid an ICE in `ptr_as_ptr` when getting the def_id of a local Fixes rust-lang#12616 `Res::def_id` can panic, so avoid calling it in favor of `opt_def_id`, so we can gracefully handle resolutions that don't have a `DefId` (e.g. local variables) and get a false negative in the worst case, rather than an ICE changelog: Fix ICE in [`ptr_as_ptr`] when the cast expression is a function call to a local variable
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avoid an ICE in `ptr_as_ptr` when getting the def_id of a local Fixes rust-lang#12616 `Res::def_id` can panic, so avoid calling it in favor of `opt_def_id`, so we can gracefully handle resolutions that don't have a `DefId` (e.g. local variables) and get a false negative in the worst case, rather than an ICE changelog: Fix ICE in [`ptr_as_ptr`] when the cast expression is a function call to a local variable
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I've been playing around with code size when linking to libstd recently, and these were some findings I found that really helped code size. I started out by eliminating all I/O implementations from libnative and instead just return an unimplemented error.
In doing so, a
fn main() {}executable was ~378K before this patch, and about 170K after the patch. These size wins are all pretty minor, but they all seemed pretty reasonable to me. With native I/O not stubbed out, this takes the size of an LTO executable from 675K to 400K.