Do not hash leading zero bytes of i64 numbers in Sip128 hasher
I was poking into the stable hasher, trying to improve its performance by compressing the number of hashed bytes. First I was experimenting with LEB128, but it was painful to implement because of the many assumptions that the SipHasher makes, so I tried something simpler - just ignoring leading zero bytes. For example, if an 8-byte integer can fit into a 4-byte integer, I will just hash the four bytes.
I wonder if this could produce any hashing ambiguity. Originally I thought so, but then I struggled to find any counter-example where this could cause different values to have the same hash. I'd be glad for any examples that could be broken by this (there are some ways of mitigating it if that would be the case). It could happen if you had e.g. 2x `u8` vs 1x `u16` hashed after one another in two different runs, but that can also happen now, without this "trick". And with collections, it should be fine, because the length is included in their hash.
I gathered some statistics for common values used in the `clap` benchmark. I observed that especially `i64` often had very low values, so I started with that type, let's see what perf does on CI.
There are some tradeoffs that we can try:
1) What types to use this optimization for? `u64`, `u32`, `u16`? Locally it was a slight loss for `u64`, I noticed that its values are often quite large.
2) What byte sizes to check? E.g. we can only distinguish between `u64`/`u32` or `u64`/`u8` instead of `u64`/`u32`/`u16`/`u8` to reduce branching (with `i64` it seemed to be better to go all the way down to `u8` locally though).
(The macro was introduced because I expect that I will be trying out this "trick" for different types).
Can you please schedule a perf. run? Thanks.
r? `@the8472`
Ignore flaky `panic-short-backtrace-windows-x86_64.rs` test for now
Mitigates (but does not fix) #92000.
It has been causing a lot of spurious test failures recently that slow
down the bors queue.
Update cargo
10 commits in fcef61230c3b6213b6b0d233a36ba4ebd1649ec3..358e79fe56fe374649275ca7aebaafd57ade0e8d
2021-12-17 02:30:38 +0000 to 2022-01-04 18:39:45 +0000
- Make rmeta_required no longer depend on whether timing is enabled (rust-lang/cargo#10254)
- The first version of pull request template (rust-lang/cargo#10218)
- Stabilize the `strip` profile option, now that rustc has stable `-C strip` (rust-lang/cargo#10088)
- Update docs for windows ssh-agent. (rust-lang/cargo#10248)
- Fix typo: substract -> subtract (rust-lang/cargo#10244)
- timings: Fix tick mark alignment (rust-lang/cargo#10239)
- Remove unused lifetimes (rust-lang/cargo#10238)
- Make levenshtein distance case insensitive. (rust-lang/cargo#10224)
- [docs] Adds basic CI yaml for GitHub Actions (rust-lang/cargo#10212)
- Add function for parsing already-read manifest (rust-lang/cargo#10209)
Rollup of 7 pull requests
Successful merges:
- #91587 (core::ops::unsize: improve docs for DispatchFromDyn)
- #91907 (Allow `_` as the length of array types and repeat expressions)
- #92515 (RustWrapper: adapt for an LLVM API change)
- #92516 (Do not use deprecated -Zsymbol-mangling-version in bootstrap)
- #92530 (Move `contains` method of Option and Result lower in docs)
- #92546 (Update books)
- #92551 (rename StackPopClean::None to Root)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Update books
## reference
3 commits in 06f9e61931bcf58b91dfe6c924057e42ce273ee1..f8ba2f12df60ee19b96de24ae5b73af3de8a446b
2021-12-17 07:31:40 -0800 to 2022-01-03 11:02:08 -0800
- Switch the default edition for examples to 2021 (rust-lang/reference#1125)
- Clarify behavior of x87 FP registers in inline assembly (rust-lang/reference#1126)
- Add inline assembly to the reference (rust-lang/reference#1105)
## book
36 commits in 8a0bb3c96e71927b80fa2286d7a5a5f2547c6aa4..d3740fb7aad0ea4a80ae20f64dee3a8cfc0c5c3c
2021-12-22 20:54:27 -0500 to 2022-01-03 21:46:04 -0500
- Add a concrete example of an optional value. Fixesrust-lang/book#2848.
- match isn't really an operator. Fixesrust-lang/book#2859
- Edits to edits of chapter 6
- Make fixes recommended by shellcheck
- Use shellcheck
- SIGH fix all the typos that were missed while spellcheck was broken
- SIGH add all the words to the dictionary that were missed while spellcheck was broken
- Remove test_harness from the dictionary
- sigh, the xkcd sandwich one
- Install aspell in CI
- set -eu in all bash scripts
- typo: assignement -> assignment
- Fix quotes
- Snapshot of ch12 for nostarch
- Use 'static lifetime earlier because that's more correct. Fixesrust-lang/book#2864.
- Add does_not_compile annotation to intermediate steps that don't compile
- Sidestep who provides output streams. Fixesrust-lang/book#2933.
- Remove note about primitive obsession. Fixesrust-lang/book#2863.
- Remove sentence encouraging writing tests on your own. Fixesrust-lang/book#2223.
- Bump mdBook version to 0.4.14 in workflow main.yml
- Past tense make better sense
- Past tense makes better sense
- Update the edition in all the listings' Cargo.toml
- Update the book to either say 2021 edition or not talk about editions
- Remove most of the 2018 edition text from the title page. Fixesrust-lang/book#2852.
- Fix word wrapping
- Emphasize return type is mandatory
- fix title capitalization
- Further edits to mention of --include-ignored, propagate to src
- feat: mention `cargo test -- --include-ignored`
- wording: get rid of "to from"
- interchanged position of `binary` and `library`
- Fix wrong word typo
- Further edits in rust-analyzer text
- appendix-04 IDE integration: Replaced rls by rust-analyzer
- Update link to Italian translation. Connects to rust-lang/book#2484.
## rustc-dev-guide
3 commits in 9bf0028b557798ddd07a6f652e4d0c635d3d6620..875464457c4104686faf667f47848aa7b0f0a744
2021-12-20 21:53:57 +0900 to 2021-12-28 22:17:49 -0600
- Update link to moved section (rust-lang/rustc-dev-guide#1282)
- Fix link in contributing.md (rust-lang/rustc-dev-guide#1280)
- Streamline "Getting Started" (rust-lang/rustc-dev-guide#1279)
Do not use deprecated -Zsymbol-mangling-version in bootstrap
`-Zsymbol-mangling-version` now produces warnings unconditionally. So if you want to use legacy mangling for the compiler (`new-symbol-mangling = false` in `config.toml`), the build is now littered with warnings.
However, with this change, stage 1 `std` doesn't compile:
```
error: `-C symbol-mangling-version=legacy` requires `-Z unstable-options`
```
Even after the bootstrap compiler is updated and it will support `-Csymbol-mangling-version`, the bootstrap code would either need to use `-Z` for the legacy mangling or use `-C` in combination with `-Z unstable-options` (because `-C` + legacy is not allowed without the unstable options). Should we just add `-Z unstable-options` to `std` compilation to resolve this?
Btw I use legacy mangling because the new mangling is not supported by [Hotspot](https://github.com/KDAB/hotspot).
Suggest single quotes when char expected, str provided
If a type mismatch occurs where a char is expected and a string literal is provided, suggest changing the double quotes to single quotes.
We already provide this suggestion in the other direction ( ' -> " ).
Especially useful for new rust devs used to a language in which single/double quotes are interchangeable.
Fixes#92479.
Remove special-cased stable hashing for HIR module
All other 'containers' (e.g. `impl` blocks) hashed their contents
in the normal, order-dependent way. However, `Mod` was hashing
its contents in a (sort-of) order-independent way. However, the
exact order is exposed to consumers through `Mod.item_ids`,
and through query results like `hir_module_items`. Therefore,
stable hashing needs to take the order of items into account,
to avoid fingerprint ICEs.
Unforuntately, I was unable to directly build a reproducer
for the ICE, due to the behavior of `Fingerprint::combine_commutative`.
This operation swaps the upper and lower `u64` when constructing the
result, which makes the function non-associative. Since we start
the hashing of module items by combining `Fingerprint::ZERO` with
the first item, it's difficult to actually build an example where
changing the order of module items leaves the final hash unchanged.
However, this appears to have been hit in practice in #92218
While we're not able to reproduce it, the fact that proc-macros
are involved (which can give an entire module the same span, preventing
any span-related invalidations) makes me confident that the root
cause of that issue is our method of hashing module items.
This PR removes all of the special handling for `Mod`, instead deriving
a `HashStable` implementation. This makes `Mod` consistent with other
'contains' like `Impl`, which hash their contents through the typical
derive of `HashStable`.
Currently the output of a command like `./x.py build --stage 0 library/std` is this:
```
Updating only changed submodules
Submodules updated in 0.02 seconds
extracting [...]
Compiling [...]
Finished dev [unoptimized] target(s) in 17.53s
Building stage0 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Compling [...]
Finished release [optimized + debuginfo] target(s) in 21.99s
Copying stage0 std from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Build completed successfully in 0:00:51
```
I find the part before the "Building stage0 std artifacts" a bit confusing.
After this commit, it looks like this:
```
Updating only changed submodules
Submodules updated in 0.02 seconds
extracting [...]
Building rustbuild
Compiling [...]
Finished dev [unoptimized] target(s) in 17.53s
Building stage0 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Compling [...]
Finished release [optimized + debuginfo] target(s) in 21.99s
Copying stage0 std from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Build completed successfully in 0:00:51
```
The "Building rustbuild" label makes it clear what the first cargo build
invocation is for. The indentation of the "Submodules updated" line
indicates it is a sub-step of a parent task.
This PR removes all of the `#[stable_hasher(project(name))]`
attributes used in HIR structs. While these attributes are not known
to be causing any issues in practice, we need to hash these in
order for the incremental system to work correctly -
a query could be otherwise be incorrectly marked green
when a change occures in one of the `Span`s that it uses.
Rollup of 6 pull requests
Successful merges:
- #90102 (Remove `NullOp::Box`)
- #92011 (Use field span in `rustc_macros` when emitting decode call)
- #92402 (Suggest while let x = y when encountering while x = y)
- #92409 (Couple of libtest cleanups)
- #92418 (Fix spacing in pretty printed PatKind::Struct with no fields)
- #92444 (Consolidate Result's and Option's methods into fewer impl blocks)
Failed merges:
- #92483 (Stabilize `result_cloned` and `result_copied`)
r? `@ghost`
`@rustbot` modify labels: rollup
Consolidate Result's and Option's methods into fewer impl blocks
`Result`'s and `Option`'s methods have historically been separated up into `impl` blocks based on their trait bounds, with the bounds specified on type parameters of the impl block. I find this unhelpful because closely related methods, like `unwrap_or` and `unwrap_or_default`, end up disproportionately far apart in source code and rustdocs:
<pre>
impl<T> Option<T> {
pub fn unwrap_or(self, default: T) -> T {
...
}
<img alt="one eternity later" src="https://user-images.githubusercontent.com/1940490/147780325-ad4e01a4-c971-436e-bdf4-e755f2d35f15.jpg" width="750">
}
impl<T: Default> Option<T> {
pub fn unwrap_or_default(self) -> T {
...
}
}
</pre>
I'd prefer for method to be in as few impl blocks as possible, with the most logical grouping within each impl block. Any bounds needed can be written as `where` clauses on the method instead:
```rust
impl<T> Option<T> {
pub fn unwrap_or(self, default: T) -> T {
...
}
pub fn unwrap_or_default(self) -> T
where
T: Default,
{
...
}
}
```
*Warning: the end-to-end diff of this PR is computed confusingly by git / rendered confusingly by GitHub; it's practically impossible to review that way. I've broken the PR into commits that move small groups of methods for which git behaves better — these each should be easily individually reviewable.*
Remove `NullOp::Box`
Follow up of #89030 and MCP rust-lang/compiler-team#460.
~1 month later nothing seems to be broken, apart from a small regression that #89332 (1aac85bb716c09304b313d69d30d74fe7e8e1a8e) shows could be regained by remvoing the diverging path, so it shall be safe to continue and remove `NullOp::Box` completely.
r? `@jonas-schievink`
`@rustbot` label T-compiler
Add `#[rustc_clean(loaded_from_disk)]` to assert loading of query result
Currently, you can use `#[rustc_clean]` to assert to that a particular
query (technically, a `DepNode`) is green or red. However, a green
`DepNode` does not mean that the query result was actually deserialized
from disk - we might have never re-run a query that needed the result.
Some incremental tests are written as regression tests for ICEs that
occured during query result decoding. Using
`#[rustc_clean(loaded_from_disk="typeck")]`, you can now assert
that the result of a particular query (e.g. `typeck`) was actually
loaded from disk, in addition to being green.
Move `PatKind::Lit` checking from ast_validation to ast lowering
Fixes#92074
This allows us to insert an `ExprKind::Err` when an invalid expression
is used in a literal pattern, preventing later stages of compilation
from seeing an unexpected literal pattern.
Rustdoc: use ThinVec for GenericArgs bindings
The bindings are almost always empty. This reduces the size of `PathSegment` and `GenericArgs` by about one fourth.
According to MDN
(https://developer.mozilla.org/en-US/docs/Web/CSS/font-size),
> To maximize accessibility, it is generally best to use values that
> are relative to the user's default font size.
> Defining font sizes in px is not accessible, because the user cannot
> change the font size in some browsers.
Note that changing font size (in browser or OS settings) is distinct
from the zoom functionality triggered with Ctrl/Cmd-+. Zoom
functionality increases the size of everything on the page, effectively
applying a multiplier to all pixel sizes. Font size changes apply to
just text.
For relative font sizes, we could use `em`, as we do in several places
already. However that has a problem of "compounding" (see MDN article
for details). The compounding problem is nicely solved by `rem`, which
make font sizes relative to the root element, not the parent element.
Since we were using a hodge-podge of pixel sizes, em, rem, and
percentage sizes before, this change switching everything to rem, while
keeping the same size relative to our old default of 16px.
16px is still the default on most browsers, for users that haven't set a
larger or smaller font size.
Stabilize -Z symbol-mangling-version=v0 as -C symbol-mangling-version=v0
This allows selecting `v0` symbol-mangling without an unstable option. Selecting `legacy` still requires -Z unstable-options.
This does not change the default symbol-mangling-version. See https://github.com/rust-lang/rust/pull/89917 for a pull request changing the default. Rationale, from #89917:
Rust's current mangling scheme depends on compiler internals; loses information about generic parameters (and other things) which makes for a worse experience when using external tools that need to interact with Rust symbol names; is inconsistent; and can contain . characters which aren't universally supported. Therefore, Rust has defined its own symbol mangling scheme which is defined in terms of the Rust language, not the compiler implementation; encodes information about generic parameters in a reversible way; has a consistent definition; and generates symbols that only use the characters A-Z, a-z, 0-9, and _.
Support for the new Rust symbol mangling scheme has been added to upstream tools that will need to interact with Rust symbols (e.g. debuggers).
This pull request allows enabling the new v0 symbol-mangling-version.
See #89917 for references to the implementation of v0, and for references to the tool changes to decode Rust symbols.
Support [x; n] expressions in concat_bytes!
Currently trying to use `concat_bytes!` with a repeating array value like `[42; 5]` results in an error:
```
error: expected a byte literal
--> src/main.rs:3:27
|
3 | let x = concat_bytes!([3; 4]);
| ^^^^^^
|
= note: only byte literals (like `b"foo"`, `b's'`, and `[3, 4, 5]`) can be passed to `concat_bytes!()`
```
This makes it so repeating array syntax can be used the same way normal arrays can be. The RFC doesn't explicitly mention repeat expressions, but it seems reasonable to allow them as well, since normal arrays are allowed.
It is possible to make the compiler get stuck compiling forever with `concat_bytes!([3; 999999999])`, but I don't think that's much of an issue since you can do that already with `const X: [u8; 999999999] = [3; 999999999];`.
Contributes to #87555.
Remove effect of `#[no_link]` attribute on name resolution
Previously it hid all non-macro names from other crates.
This has no relation to linking and can change name resolution behavior in some cases (e.g. glob conflicts), in addition to just producing the "unresolved name" errors.
I can kind of understand the possible reasoning behind the current behavior - if you can use names from a `no_link` crates then you can use, for example, functions too, but whether it will actually work or produce link-time errors will depend on random factors like inliner behavior.
(^^^ This is not the actual reason why the current behavior exist, I've looked through git history and it's mostly accidental.)
I think this risk is ok for such an obscure attribute, and we don't need to specifically prevent use of non-macro items from such crates.
(I'm not actually sure why would anyone use `#[no_link]` on a crate, even if it's macro only, if you aware of any use cases, please share. IIRC, at some point it was used for crates implementing custom derives - the now removed legacy ones, not the current proc macros.)
Extracted from https://github.com/rust-lang/rust/pull/91795.
Emit an error for `--cfg=)`
Fixes#73026
See also: #64467, #89468
The issue stems from a `FatalError` being silently raised in
`panictry_buffer`. Normally this is not a problem, because
`panictry_buffer` emits the causes of the error, but they are not
themselves fatal, so they get filtered out by the silent emitter.
To fix this, we use a parser entrypoint which doesn't use
`panictry_buffer`, and we handle the error ourselves.
Add test for where clause order
I didn't use ``@snapshot`` because of the ` ` characters, it's much simpler doing it through rustdoc-gui testsuite.
r? `@camelid`
Reduce compile time of rustbuild
Best reviewed commit by commit. The `ignore` crate and it's dependencies are probably responsible for the majority of the compile time after this PR.
cc `@jyn514` as you got a couple of open rustbuild PR.
Fixes#92074
This allows us to insert an `ExprKind::Err` when an invalid expression
is used in a literal pattern, preventing later stages of compilation
from seeing an unexpected literal pattern.
This slightly improves compilation time by reducing linking time
(saving about a 1/10 of the the total compilation time after
changing rustbuild) and slightly reduces disk usage (from 16MB for
the rustc wrapper to 4MB).
The task of the macro is simple enough that a decl macro is almost ten
times shorter than the original proc macro. The proc macro is 159 lines
while the decl macro is just 18 lines.
This reduces the amount of dependencies of rustbuild from 45 to 37. It
also slight reduces compilation time from 47s to 44s for debug builds.
Mark drop calls in landing pads `cold` instead of `noinline`
Now that deferred inlining has been disabled in LLVM (#92110), this shouldn't cause catastrophic size blowup.
I confirmed that the test cases from https://github.com/rust-lang/rust/issues/41696#issuecomment-298696944 still compile quickly (<1s) after this change. ~Although note that I wasn't able to reproduce the original issue using a recent rustc/llvm with deferred inlining enabled, so those tests may no longer be representative. I was also unable to create a modified test case that reproduced the original issue.~ (edit: I reproduced it on CI by accident--the first commit timed out on the LLVM 12 builder, because I forgot to make it conditional on LLVM version)
r? `@nagisa`
cc `@arielb1` (this effectively reverts #42771 "mark calls in the unwind path as !noinline")
cc `@RalfJung` (fixes#46515)
edit: also fixes#87055
[rustc_builtin_macros] add indices to format_foreign::printf::Substitution::Escape
Fixes#92267.
The problem was that the escape string "%%" does not need to appear at the very beginning of the format string, but
the iterator implementation assumed that it did.
The solution follows the pattern used by `format_foregin:🐚:Subtitution::Escape`: 8ed935e92d/compiler/rustc_builtin_macros/src/format_foreign.rs (L629)
Fix whitespace in pretty printed PatKind::Range
Follow-up to #92238 fixing one of the FIXMEs.
```rust
macro_rules! repro {
($pat:pat) => {
stringify!($pat)
};
}
fn main() {
println!("{}", repro!(0..=1));
}
```
Before: `0 ..=1`
After: `0..=1`
The canonical spacing applied by rustfmt has no space after the lower expr. Rustc's parser diagnostics also do not put a space there:
df96fb166f/compiler/rustc_parse/src/parser/pat.rs (L754)
Lock bootstrap (x.py) build directory
Closes#76661, closes#80849,
`x.py` creates a lock file at `project_root/lock.db`
r? `@jyn514` , because he was one that told me about this~
Fixes#73026
See also: #64467, #89468
The issue stems from a `FatalError` being silently raised in
`panictry_buffer`. Normally this is not a problem, because
`panictry_buffer` emits the causes of the error, but they are not
themselves fatal, so they get filtered out by the silent emitter.
To fix this, we use a parser entrypoint which doesn't use
`panictry_buffer`, and we handle the error ourselves.
config.rs: Add support for a per-target default_linker option.
* src/bootstrap/config.rs (Target) <default_linker>: New field.
(TomlTarget): Likewise.
* src/bootstrap/compile.rs (rustc_cargo_env): Prefer a
target-specified default_linker over a global one if available.
* config.toml.example: Adjust doc.
Import `SourceFile`s from crate before decoding foreign `Span`
Fixes#92163Fixes#92014
When writing to the incremental cache, we encode all `Span`s
we encounter, regardless of whether or not their `SourceFile`
comes from the local crate, or from a foreign crate.
When we decode a `Span`, we use the `StableSourceFileId` we encoded
to locate the matching `SourceFile` in the current session. If this
id corresponds to a `SourceFile` from another crate, then we need to
have already imported that `SourceFile` into our current session.
This usually happens automatically during resolution / macro expansion,
when we try to resolve definitions from other crates. In certain cases,
however, we may try to load a `Span` from a transitive dependency
without having ever imported the `SourceFile`s from that crate, leading
to an ICE.
This PR fixes the issue by enconding the `SourceFile`'s `CrateNum`
when we encode a `Span`. During decoding, we call `imported_source_files()`
when we encounter a foreign `CrateNum`, which ensure that all
`SourceFile`s from that crate are imported into the current session.
Prevent spurious build failures and other bugs caused by parallel runs of
x.py. We back the lock with sqlite, so that we have a cross-platform locking
strategy, and which can be done nearly first in the build process (from Python),
which helps move the lock as early as possible.
Refactor variance diagnostics to work with more types
Instead of special-casing mutable pointers/references, we
now support general generic types (currently, we handle
`ty::Ref`, `ty::RawPtr`, and `ty::Adt`)
When a `ty::Adt` is involved, we show an additional note
explaining which of the type's generic parameters is
invariant (e.g. the `T` in `Cell<T>`). Currently, we don't
explain *why* a particular generic parameter ends up becoming
invariant. In the general case, this could require printing
a long 'backtrace' of types, so doing this would be
more suitable for a follow-up PR.
We still only handle the case where our variance switches
to `ty::Invariant`.
Instead of special-casing mutable pointers/references, we
now support general generic types (currently, we handle
`ty::Ref`, `ty::RawPtr`, and `ty::Adt`)
When a `ty::Adt` is involved, we show an additional note
explaining which of the type's generic parameters is
invariant (e.g. the `T` in `Cell<T>`). Currently, we don't
explain *why* a particular generic parameter ends up becoming
invariant. In the general case, this could require printing
a long 'backtrace' of types, so doing this would be
more suitable for a follow-up PR.
We still only handle the case where our variance switches
to `ty::Invariant`.
Add codegen option for branch protection and pointer authentication on AArch64
The branch-protection codegen option enables the use of hint-space pointer
authentication code for AArch64 targets.
rustc_metadata: Encode list of all crate's traits into metadata
While working on https://github.com/rust-lang/rust/pull/88679 I noticed that rustdoc is casually doing something quite expensive, something that is used only for error reporting in rustc - collecting all traits from all crates in the dependency tree.
This PR trades some minor extra time spent by metadata encoder in rustc for major gains for rustdoc (and for rustc runs with errors, which execute the `all_traits` query for better diagnostics).
compiletest: Remove some vestigial code
The `check_lines` header is no longer parsed as a header, but instead inside the debuginfo tests. I believe this was changed in #13726.
Print space after formal generic params in fn type
Follow-up to #92238 fixing one of the FIXMEs.
```rust
macro_rules! repro {
($ty:ty) => {
stringify!($ty)
};
}
fn main() {
println!("{}", repro!(for<'a> fn(&'a u8)));
}
```
Before: `for<'a>fn(&'a u8)`
After: `for<'a> fn(&'a u8)`
The pretty printer's `print_formal_generic_params` already prints formal generic params correctly with a space, we just need to call it when printing BareFn types instead of reimplementing the printing incorrectly without a space.
83b15bfe1c/compiler/rustc_ast_pretty/src/pprust/state.rs (L1394-L1400)
