Replace str's transmute() calls with pointer casts
After the following conversation in #rust-lang:
```
[14:43:50] <Ixrec> TIL the implementation of from_utf_unchecked is literally just "mem::transmute(x)"
[14:43:59] <Ixrec> no wonder people keep saying transmute is overpowered
[15:15:30] <eddyb> Ixrec: it should be a pointer cast lol
[15:15:46] <eddyb> unless it doesn't let you
[16:50:34] <Ixrec> https://play.rust-lang.org/?gist=d1e6b629ad9ec1baf64ce261c63845e6&version=stable seems like it does let me
[16:52:35] <eddyb> Ixrec: yeah that's the preferred impl
[16:52:46] <eddyb> Ixrec: it just wasn't in 1.0
[16:52:50] <eddyb> IIRC
[16:53:00] <eddyb> (something something fat pointers)
```
Since I already wrote half of the preferred impls in the playground, might as well make an actual PR.
Document thread builder panics for nul bytes in thread names
This seems to have been undocumented. Mention this where the name is set
(Builder::name) and where the panic could happen (Builder::spawn).
Thread::new is private and I think the builder is the only user where
this matters. A short comment was added to "document" Thread::new too.
Add proper help line for `-C inline threshold`
Looks like someone accidentally some words when adding this.
This also remove a period on a different help line for consistency, as no options have a period.
Add Cow<str> -> Box<Error> impls.
Considering how impls exist for `String` and `&str`, it makes sense to also add an impl for `Cow<str>` as well.
This would allow converting `String::from_utf8_lossy` directly into a `Box<Error>` or `io::Error` without having to add an extra `into_ownd()`.
incr.comp.: Compute fingerprint for all query results.
This PR enables query result fingerprinting in incremental mode. This is an essential piece of infrastructure for red/green tracking. We don't do anything with the fingerprints yet but merging the infrastructure should protect it from bit-rotting and will make it easier to start measuring its performance impact (and thus let us determine if we should switch to a faster hashing algorithm rather sooner than later).
Note, this PR also includes the changes from https://github.com/rust-lang/rust/pull/43887 which I'm therefore closing. No need to re-review the first commit though.
r? @nikomatsakis
- Don't hash traits in scope as part of HIR hashing any more.
- Some queries returned DefIndexes from other crates.
- Provide a generic way of stably hashing maps (not used everywhere yet).
This makes sure that we don't introduce strange cases where we have
nodes outside the query system that could break red/green tracking
and it will allow to keep red/green neatly encapsulated within the
DepGraph implementation.
Run the miri test suite on the aux builder and travis
Reopen of #38350
see https://github.com/rust-lang/rust/pull/43340#issuecomment-316940762 for earlier discussion
Rationale for running miri's test suite in rustc's CI is that miri currently contains many features that we want in const eval in the future, and these features would break if the test suite is not run.
fixes#44077
r? @nikomatsakis
cc @eddyb
Refactor translation unit partitioning/collection as a query
This commit is targeted at #44486 with the ultimate goal of making the `collect_and_partition_translation_items` function a query. This mostly just involved query-ifying a few other systems along with plumbing the tcx instead of `SharedCrateContext` in a few locations.
Currently this only tackles the first bullet of #44486 and doesn't add a dedicated query for a particular codegen unit. I wasn't quite sure how to do that yet but figured this was good to put up.
Closes#44486
This commit moves the actual code generation in the compiler behind a query
keyed by a codegen unit's name. This ended up entailing quite a few internal
refactorings to enable this, along with a few cut corners:
* The `OutputFilenames` structure is now tracked in the `TyCtxt` as it affects a
whole bunch of trans and such. This is now behind a query and threaded into
the construction of the `TyCtxt`.
* The `TyCtxt` now has a channel "out the back" intended to send data to worker
threads in rustc_trans. This is used as a sort of side effect of the codegen
query but morally what's happening here is the return value of the query
(currently unit but morally a path) is only valid once the background threads
have all finished.
* Dispatching work items to the codegen threads was refactored to only rely on
data in `TyCtxt`, which mostly just involved refactoring where data was
stored, moving it from the translation thread to the controller thread's
`CodegenContext` or the like.
* A new thread locals was introduced in trans to work around the query
system. This is used in the implementation of `assert_module_sources` which
looks like an artifact of the old query system and will presumably go away
once red/green is up and running.
rustbuild: Don't pass `-j` if called by `make`
In these situations Cargo just prints out a warning about ignoring the flag
anyway, so let `make` take care of jobs and whatnot instead of getting warnings
printed.
This commit attaches a channel to the LLVM workers to the `TyCtxt` which will
later be used during the codegen query to actually send work to LLVM workers.
Otherwise this commit is just plumbing this channel throughout the compiler to
ensure it reaches the right consumers.
This commit removes the `crate_trans_items` field from the `CrateContext` of
trans. This field, a big map, was calculated during partioning and was a set of
all translation items. This isn't quite incremental-friendly because the map may
change a lot but not have much effect on downstream consumers.
Instead a new query was added for the one location this map was needed, along
with a new comment explaining what the location is doing!
This is a big map that ends up inside of a `CrateContext` during translation for
all codegen units. This means that any change to the map may end up causing an
incremental recompilation of a codegen unit! In order to reduce the amount of
dependencies here between codegen units and the actual input crate this commit
refactors dealing with exported symbols and such into various queries.
The new queries are largely based on existing queries with filled out
implementations for the local crate in addition to external crates, but the main
idea is that while translating codegen untis no unit needs the entire set of
exported symbols, instead they only need queries about particulare `DefId`
instances every now and then.
The linking stage, however, still generates a full list of all exported symbols
from all crates, but that's going to always happen unconditionally anyway, so no
news there!
Otherwise we may emit double errors related to the `#[export_name]` attribute,
for example, and using a query should ensure that it's only emitted at most
once.
This commit moves the `collect_and_partition_translation_items` function into a
query on `TyCtxt` instead of a free function in trans, allowing us to track
dependencies and such of the function.
This commit moves the definition of the `ExportedSymbols` structure to the
`rustc` crate and then creates a query that'll be used to construct the
`ExportedSymbols` set. This in turn uses the reachablity query exposed in the
previous commit.
This commit refactors the the `partitioning::partition` function to operate with
a `TyCtxt` instead of a `SharedCrateContext` in preparation for making it a
query.
