Joshua Nelson [Sun, 20 Sep 2020 06:18:09 +0000 (02:18 -0400)]
Fix intra-doc links for primitives
- Add `PrimTy::name` and `PrimTy::name_str`
- Use those new functions to distinguish between the name in scope and
the canonical name
- Fix diagnostics for primitive types
- Add tests for primitives
Joshua Nelson [Sun, 20 Sep 2020 04:32:00 +0000 (00:32 -0400)]
Perform most diagnostic lookups in `resolution_failure`
Previously, these were spread throughout the codebase. This had two
drawbacks:
1. It caused the fast path to be slower: even if a link resolved,
rustdoc would still perform various lookups for the error diagnostic.
2. It was inconsistent and didn't always give all diagnostics (https://github.com/rust-lang/rust/issues/76925)
Now, diagnostics only perform expensive lookups in the error case.
Additionally, the error handling is much more consistent, both in
wording and behavior.
- Remove `CannotHaveAssociatedItems`, `NotInScope`, `NoAssocItem`, and `NotAVariant`
in favor of the more general `NotResolved`
`resolution_failure` will now look up which of the four above
categories is relevant, instead of requiring the rest of the code to
be consistent and accurate in which it picked.
- Remove unnecessary lookups throughout the intra-doc link pass. These
are now done by `resolution_failure`.
+ Remove unnecessary `extra_fragment` argument to `variant_field()`;
it was only used to do lookups on failure.
+ Remove various lookups related to associated items
+ Remove distinction between 'not in scope' and 'no associated item'
- Don't perform unnecessary copies
- Remove unused variables and code
- Update tests
- Note why looking at other namespaces is still necessary
- 'has no inner item' -> 'contains no item'
Auto merge of #76626 - jyn514:x.py-changelog, r=Mark-Simulacrum
Add a changelog for x.py and nag contributors until they read it
Add a changelog for x.py
- Add a changelog and instructions for updating it
- Use `changelog-seen` in `config.toml` and `VERSION` in bootstrap to determine whether the changelog has been read. There's no way to tie reading the changelog to updating the version, so unfortunately they still have to update `config.toml` manually. Actually reading the changelog is optional, anyone can set `changelog-seen = N` without reading (although it's not recommended).
- Nag people if they haven't read the x.py changelog
+ Print message twice to make sure it's seen
- Give different error messages depending on whether the version needs to be updated or added
Auto merge of #76799 - Mark-Simulacrum:fix-cross-compile-dist, r=alexcrichton
Fix cross compiling dist/build invocations
I am uncertain why the first commit is not affecting CI. I suspect it's because we pass --disable-docs on most of our cross-compilation builders. The second commit doesn't affect CI because CI runs x.py dist, not x.py build.
Both commits are standalone; together they should resolve #76733. The first commit doesn't really fix that issue but rather just fixes cross-compiled x.py dist, resolving a bug introduced in #76549.
Auto merge of #77039 - ecstatic-morse:rollup-qv3jj4a, r=ecstatic-morse
Rollup of 13 pull requests
Successful merges:
- #72734 (Reduce duplicate in liballoc reserve error handling)
- #76131 (Don't use `zip` to compare iterators during pretty-print hack)
- #76150 (Don't recommend ManuallyDrop to customize drop order)
- #76275 (Implementation of Write for some immutable ref structs)
- #76489 (Add explanation for E0756)
- #76581 (do not ICE on bound variables, return `TooGeneric` instead)
- #76655 (Make some methods of `Pin` unstable const)
- #76783 (Only get ImplKind::Impl once)
- #76807 (Use const-checking to forbid use of unstable features in const-stable functions)
- #76888 (use if let instead of single match arm expressions)
- #76914 (extend `Ty` and `TyCtxt` lints to self types)
- #77022 (Reduce boilerplate for BytePos and CharPos)
- #77032 (lint missing docs for extern items)
Rollup merge of #76807 - ecstatic-morse:const-checking-staged-api, r=oli-obk
Use const-checking to forbid use of unstable features in const-stable functions
First step towards #76618.
Currently this code isn't ever hit because `qualify_min_const_fn` runs first and catches pretty much everything. One exception is `const_precise_live_drops`, which does not use the newly added code since it runs as part of a separate pass.
Also contains some unrelated refactoring, which is split into separate commits.
Rollup merge of #76150 - matklad:droporder, r=withoutboats
Don't recommend ManuallyDrop to customize drop order
See
https://internals.rust-lang.org/t/need-for-controlling-drop-order-of-fields/12914/21
for the discussion.
TL;DR: ManuallyDrop is unsafe and footguny, but you can just ask the compiler to do all the work for you by re-ordering declarations.
Specifically, the original example from the docs is much better written as
```rust
struct Peach;
struct Banana;
struct Melon;
struct FruitBox {
melon: Melon,
// XXX: mind the relative drop order of the fields below
peach: Peach,
banana: Banana,
}
```
Rollup merge of #76131 - Aaron1011:fix/pretty-print-zip, r=lcnr
Don't use `zip` to compare iterators during pretty-print hack
If the right-hand iterator has exactly one more element than the
left-hand iterator, then both iterators will be fully consumed, but
the extra element will never be compared.
Split out from https://github.com/rust-lang/rust/pull/76130
Auto merge of #76913 - vandenheuvel:performance_debug, r=lcnr
Fixing the performance regression of #76244
Issue https://github.com/rust-lang/rust/issues/74865 suggested that removing the `def_id` field from `ParamEnv` would improve performance. PR https://github.com/rust-lang/rust/pull/76244 implemented this change.
Generally, [results](https://perf.rust-lang.org/compare.html?start=80fc9b0ecb29050d45b17c64af004200afd3cfc2&end=5ef250dd2ad618ee339f165e9b711a1b4746887d) were as expected: an instruction count decrease of about a percent. The instruction count for the unicode crates increased by about 3%, which `@nnethercote` speculated to be caused by a quirk of inlining or codegen. As the results were generally positive, and for chalk integration, this was also a step in the right direction, the PR was r+'d regardless.
Auto merge of #77003 - joshtriplett:remove-duplicate-link-libraries, r=Mark-Simulacrum
Remove duplicated library links between std and libc
The libc crate is already responsible for linking in the appropriate
libraries, and std doing the same thing results in duplicated library
names on the linker command line. Removing this duplication slightly
reduces linker time, and makes it simpler to adjust the set or order of
linked libraries in one place (such as to add static linking support).
Aaron Hill [Sun, 30 Aug 2020 22:08:16 +0000 (18:08 -0400)]
Don't use `zip` to compare iterators during pretty-print hack
If the right-hand iterator has exactly one more element than the
left-hand iterator, then both iterators will be fully consumed, but
the extra element will never be compared.
Auto merge of #76680 - Julian-Wollersberger:nongeneric_ensure_sufficient_stack, r=jyn514
Make `ensure_sufficient_stack()` non-generic, using cargo-llvm-lines
Inspired by [this blog post](https://blog.mozilla.org/nnethercote/2020/08/05/how-to-speed-up-the-rust-compiler-some-more-in-2020/) from `@nnethercote,` I used [cargo-llvm-lines](https://github.com/dtolnay/cargo-llvm-lines/) on the rust compiler itself, to improve it's compile time. This PR contains only one low-hanging fruit, but I also want to share some measurements.
The function `ensure_sufficient_stack()` was monomorphized 1500 times, and with it the `stacker` and `psm` crates, for a total of 1.5% of all llvm IR lines. With some trickery I convert the generic closure into a dynamic one, and thus all that code is only monomorphized once.
# Measurements
Getting these numbers took some fiddling with CLI flags and I [modified](https://github.com/Julian-Wollersberger/cargo-llvm-lines/blob/master/src/main.rs#L115) cargo-llvm-lines to read from a folder instead of invoking cargo. Commands I used:
```
./x.py clean
RUSTFLAGS="--emit=llvm-ir -C link-args=-fuse-ld=lld -Z self-profile=profile" CARGOFLAGS_BOOTSTRAP="-Ztimings" RUSTC_BOOTSTRAP=1 ./x.py build -i --stage 1 library/std
# Then manually copy all .ll files into a folder I hardcoded in cargo-llvm-lines in main.rs#L115
cd ../cargo-llvm-lines
cargo run llvm-lines
```
All `.ll` files together had 4.4GB. After my change they had 4.2GB. So a few percent less code LLVM has to process. Hurray!
Sadly, I couldn't measure an actual wall-time improvement. Watching YouTube while compiling added to much noise...
Here is the top of the list after the change:
``` 16460866 (100%) 58341 (100%) (TOTAL) 1903085 (11.6%) 504 (0.9%) rustc_query_system::query::plumbing::get_query_impl::{{closure}} 1331918 (8.1%) 1287 (2.2%) hashbrown::raw::RawTable<T>::reserve_rehash
777796 (4.7%) 12031 (20.6%) core::ptr::drop_in_place
551462 (3.4%) 1519 (2.6%) rustc_data_structures::stack::ensure_sufficient_stack::{{closure}}
```
Note that the total was reduced by 430 000 lines and `psm::on_stack::with_on_stack` has disappeared. Instead `rustc_data_structures::stack::ensure_sufficient_stack::{{closure}}` appeared. I'm confused about that one, but it seems to consist of inlined calls to `rustc_query_system::*` stuff.
Further note the other two big culprits in this list: `rustc_query_system` and `hashbrown`. These two are monomorphized many times, the query system summing to more than 20% of all lines, not even counting code that's probably inlined elsewhere.
Assuming compile times scale linearly with llvm-lines, that means a possible 20% compile time reduction.
Reducing eg. `get_query_impl` would probably need a major refactoring of the qery system though. _Everything_ in there is generic over multiple types, has associated types and passes generic Self arguments by value. Which means you can't simply make things `dyn`.
---------------------------------------
This PR is a small step to make rustc compile faster and thus make contributing to rustc less painful. Nonetheless I love Rust and I find the work around rustc fascinating :)
Auto merge of #77013 - RalfJung:rollup-84ut0xq, r=RalfJung
Rollup of 10 pull requests
Successful merges:
- #76439 (Add error explanation for E0755)
- #76521 (Fix segfault if pthread_getattr_np fails)
- #76835 (make replace_prefix only take &str as arguments )
- #76967 (Revert adding Atomic::from_mut.)
- #76977 (Add a regression test for copy propagation miscompilation)
- #76981 (liballoc bench use imported path Bencher)
- #76983 (BTreeMap: extra testing & fixed comments)
- #76996 (Fix typo in rustc_lexer docs)
- #77009 (Dogfood total_cmp in the test crate)
- #77012 (update Miri for another bugfix)
Rollup merge of #76521 - tavianator:fix-pthread-getattr-destroy, r=Amanieu
Fix segfault if pthread_getattr_np fails
glibc [destroys][1] the passed pthread_attr_t if pthread_getattr_np()
fails. Destroying it again leads to a segfault. Fix it by only
destroying it on success for glibc.
Joshua Nelson [Sat, 12 Sep 2020 02:55:16 +0000 (22:55 -0400)]
Add a changelog for x.py
- Add a changelog and instructions for updating it
- Use `changelog-seen` in `config.toml` and `VERSION` in bootstrap to determine whether the changelog has been read
- Nag people if they haven't read the x.py changelog
+ Print message twice to make sure it's seen
- Give different error messages depending on whether the version needs to be updated or added
This PR tries to move the sound `&mut UnsafeCell<T> -> &mut T` projection that all the "downstream" constructions were already relying on, up to the root abstraction, where it rightfully belongs, and officially blessing it.
- this **helps reduce the amount of `unsafe` snippets out there** (_c.f._, the second commit of this PR: https://github.com/rust-lang/rust/pull/76936/commits/09503fd1b30c83ca605546fa3f899721e41e68c6)
The fact that this getter is now expose for `UnsafeCell<T>` itself, will also help convey the idea that **`UnsafeCell` is not magical _w.r.t._ `&mut` accesses**, contrary to what some people incorrectly think.
- Even the standard library itself at some point had such a confusion, _c.f._ this comment where there is a mention of multi-threaded (and thus _shared_) access despite dealing with exclusive references over unique ownership: https://github.com/rust-lang/rust/blob/59fb88d061544a035f3043b47594b34789204cee/library/core/src/cell.rs#L498-L499
Rollup merge of #76872 - khyperia:remove_declare_methods, r=eddyb
Remove DeclareMethods
Most of the `DeclareMethods` API was only used internally by rustc_codegen_llvm. As such, it makes no sense to require other backends to implement them.
(`get_declared_value` and `declare_cfn` were used, in one place, specific to the `main` symbol, which I've replaced with a more specialized function to allow more flexibility in implementation - the intent is that `declare_c_main` can go away once we do something more clever, e.g. @eddyb has ideas around having a MIR shim or somesuch we can explore in a follow-up PR)
Rollup merge of #76628 - jyn514:default-config-files, r=Mark-Simulacrum
Add sample defaults for config.toml
- Allow including defaults in `src/bootstrap/defaults` using `profile = "..."`.
- Add default config files, with a README noting they're experimental and asking you to open an issue if you run into trouble. The config files have comments explaining why the defaults are set.
- Combine config files using the `merge` dependency.
This introduces a new dependency on `merge` that hasn't yet been vetted.
I want to improve the output when `include = "x"` isn't found:
```
thread 'main' panicked at 'fs::read_to_string(&file) failed with No such file or directory (os error 2) ("configuration file did not exist")', src/bootstrap/config.rs:522:28
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
failed to run: /home/joshua/rustc/build/bootstrap/debug/bootstrap test tidy
Build completed unsuccessfully in 0:00:00
```
However that seems like it could be fixed in a follow-up.
Rollup merge of #76135 - CDirkx:const-option, r=dtolnay,oli-obk
Stabilize some Option methods as const
Stabilize the following methods of `Option` as const:
- `is_some`
- `is_none`
- `as_ref`
These methods are currently const under the unstable feature `const_option` (tracking issue: #67441).
I believe these methods to be eligible for stabilization because of the stabilization of #49146 (Allow if and match in constants) and the trivial implementations, see also: [PR#75463](https://github.com/rust-lang/rust/pull/75463).
Remove duplicated library links between std and libc
The libc crate is already responsible for linking in the appropriate
libraries, and std doing the same thing results in duplicated library
names on the linker command line. Removing this duplication slightly
reduces linker time, and makes it simpler to adjust the set or order of
linked libraries in one place (such as to add static linking support).
Auto merge of #76843 - kornelski:longtypetofile, r=ecstatic-morse
Let user see the full type of type-length limit error
Seeing the full type of the error is sometimes essential to diagnosing the problem, but the type itself is too long to be displayed in the terminal in a useful fashion. This change solves this dilemma by writing the full offending type name to a file, and displays this filename as a note.
> note: the full type name been written to '$TEST_BUILD_DIR/issues/issue-22638/issue-22638.long-type.txt'
Auto merge of #75974 - SkiFire13:peekmut-opt-sift, r=LukasKalbertodt
Avoid useless sift_down when std::collections::binary_heap::PeekMut is never mutably dereferenced
If `deref_mut` is never called then it's not possible for the element to be mutated without internal mutability, meaning there's no need to call `sift_down`.
This could be a little improvement in cases where you want to mutate the biggest element of the heap only if it satisfies a certain predicate that needs only read access to the element.
Auto merge of #76295 - mati865:remove-mmx, r=Amanieu,oli-obk
Remove MMX from Rust
Follow-up to https://github.com/rust-lang/stdarch/pull/890
This removes most of MMX from Rust (tests pass with small changes), keeping stable `is_x86_feature_detected!("mmx")` working.
Auto merge of #76544 - Mark-Simulacrum:less-python, r=alexcrichton
De-couple Python and bootstrap slightly
This revises rustbuild's entry points from Python to rely less on magic environment variables, preferring to use Cargo-provided environment variables where feasible.
Notably, BUILD_DIR and BOOTSTRAP_CONFIG are *not* moved, because both more-or-less have some non-trivial discovery logic and replicating it in rustbuild seems unfortunate; if it moved to Cargo that would be a different story.
Joshua Nelson [Sat, 12 Sep 2020 04:42:52 +0000 (00:42 -0400)]
Add sample defaults for config.toml
- Allow including defaults in `src/bootstrap/defaults` using `profile = "..."`
- Add default config files
- Combine config files using the merge dependency.
- Add comments to default config files
- Add a README asking to open an issue if the defaults are bad
- Give a loud error if trying to merge `.target`, since it's not
currently supported
- Use an exhaustive match
- Use `<none>` in config.toml.example to avoid confusion
- Fix bugs in `Merge` derives
Previously, it would completely ignore the profile defaults if there
were any settings in `config.toml`. I sent an email to the `merge` maintainer
asking them to make the behavior in this commit the default.
This introduces a new dependency on `merge` that hasn't yet been vetted.
I want to improve the output when `include = "x"` isn't found:
```
thread 'main' panicked at 'fs::read_to_string(&file) failed with No such file or directory (os error 2) ("configuration file did not exist")', src/bootstrap/config.rs:522:28
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
failed to run: /home/joshua/rustc/build/bootstrap/debug/bootstrap test tidy
Build completed unsuccessfully in 0:00:00
```
However that seems like it could be fixed in a follow-up.
Mark Rousskov [Mon, 7 Sep 2020 01:32:55 +0000 (21:32 -0400)]
Remove support for different src directory
This requires that bootstrap is run from the same worktree as the sources it'll
build, but this is basically required for the build to work anyway. You can
still run it from a different directory, just that the files it builds must be
beside it.
Mark Rousskov [Sun, 6 Sep 2020 23:57:07 +0000 (19:57 -0400)]
Set BUILD_TRIPLE via build script
This moves build triple discovery for rustbuild from bootstrap.py into a build
script, meaning it will "just work" if building rustbuild via Cargo rather than
Python.
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