These need to be inlined across crates to avoid showing up as one-instruction
functions in profiles! In the benchmark from #43578 this decreased the
translation item collection step from 30s to 23s, and looks like it also allowed
vectorization elsewhere of the operations!
Commit c4710203c0 in #43492 make `LLVMRustHasFeature` "more robust"
by using `getFeatureTable()`. However, this function is specific to
Rust's own LLVM fork, not upstream LLVM-4.0, so we need to use
`#if LLVM_RUSTLLVM` to guard this call.
borrowck: skip CFG construction when there is nothing to propagate
CFG construction takes a large amount of time and memory, especially for
large constants. If such a constant contains no actions on lvalues, it
can't have borrowck problems and can be ignored by it.
This removes the 4.9GB borrowck peak from #36799. It seems that HIR had
grown by 300MB and MIR had grown by 500MB from the last massif
collection and that remains to be investigated, but this at least shaves
the borrowck peak.
r? @nikomatsakis
Set `LLVM_LINK_LLVM_DYLIB=ON` -- "If enabled, tools will be linked with
the libLLVM shared library." Rust doesn't ship any of the LLVM tools,
and only needs a few at all for some test cases, so statically linking
the tools is just a waste of space. I've also had memory issues on
slower machines with LLVM debuginfo enabled, when several tools start
linking in parallel consuming several GBs each.
With the default configuration, `build/x86_64-unknown-linux-gnu/llvm`
was 1.5GB before, now down to 731MB. The difference is more drastic
with `--enable-llvm-release-debuginfo`, from 28GB to "only" 13GB.
This does not change the linking behavior of `rustc_llvm`.
Removing nops can allow more basic blocks to be merged, but merging
basic blocks can't allow for more nops to be removed, so we should
remove nops first.
This doesn't matter *that* much, because normally we run SimplifyCfg
several times, but there's no reason not to do it.
I saw MIR cache invalidation somewhat hot on my profiler when per-BB
indexin was used. That shouldn't matter much, but there is no good
reason not to use an iterator.
default binding modes: add pat_binding_modes
This PR kicks off the implementation of the [default binding modes RFC][1] by
introducing the `pat_binding_modes` typeck table mentioned in the [mentoring
instructions][2].
It is a WIP because I wasn't able to avoid all uses of the binding modes as
not all call sites are close enough to the typeck tables. I added marker
comments to any line matching `BindByRef|BindByValue` so that reviewers
are aware of all of them.
I will look into changing the HIR (as suggested in [2]) to not carry a
`BindingMode` unless one was explicitly specified, but this PR is good for
a first round of comments.
The actual changes are quite small and CI will fail due to overlong lines
caused by the marker comments.
See #42640.
cc @nikomatsakis
[1]: https://github.com/rust-lang/rfcs/pull/2005
[2]: https://github.com/rust-lang/rust/issues/42640#issuecomment-313535089
CFG construction takes a large amount of time and memory, especially for
large constants. If such a constant contains no actions on lvalues, it
can't have borrowck problems and can be ignored by it.
This removes the 4.9GB borrowck peak from #36799. It seems that HIR had
grown by 300MB and MIR had grown by 500MB from the last massif
collection and that remains to be investigated, but this at least shaves
the borrowck peak.
