Add IEEE 754 compliant fmt/parse of -0, infinity, NaN
This pull request improves the Rust float formatting/parsing libraries to comply with IEEE 754's formatting expectations around certain special values, namely signed zero, the infinities, and NaN. It also adds IEEE 754 compliance tests that, while less stringent in certain places than many of the existing flt2dec/dec2flt capability tests, are intended to serve as the beginning of a roadmap to future compliance with the standard. Some relevant documentation is also adjusted with clarifying remarks.
This PR follows from discussion in https://github.com/rust-lang/rfcs/issues/1074, and closes#24623.
The most controversial change here is likely to be that -0 is now printed as -0. Allow me to explain: While there appears to be community support for an opt-in toggle of printing floats as if they exist in the naively expected domain of numbers, i.e. not the extended reals (where floats live), IEEE 754-2019 is clear that a float converted to a string should be capable of being transformed into the original floating point bit-pattern when it satisfies certain conditions (namely, when it is an actual numeric value i.e. not a NaN and the original and destination float width are the same). -0 is given special attention here as a value that should have its sign preserved. In addition, the vast majority of other programming languages not only output `-0` but output `-0.0` here.
While IEEE 754 offers a broad leeway in how to handle producing what it calls a "decimal character sequence", it is clear that the operations a language provides should be capable of round tripping, and it is confusing to advertise the f32 and f64 types as binary32 and binary64 yet have the most basic way of producing a string and then reading it back into a floating point number be non-conformant with the standard. Further, existing documentation suggested that e.g. -0 would be printed with -0 regardless of the presence of the `+` fmt character, but it prints "+0" instead if given such (which was what led to the opening of #24623).
There are other parsing and formatting issues for floating point numbers which prevent Rust from complying with the standard, as well as other well-documented challenges on the arithmetic level, but I hope that this can be the beginning of motion towards solving those challenges.
compiletest: handle llvm_version with suffix like "12.0.0libcxx"
The previous code only remove the suffix begin with `-`, but Gentoo Linux [define `LLVM_VERSION_SUFFIX="libcxx"`](604d79f327/sys-devel/llvm/llvm-11.1.0.ebuild (L378)) when llvm is linked to libc++ and lead to a panic:
```
thread 'main' panicked at 'Malformed version component: ParseIntError { kind: InvalidDigit }', src/tools/compiletest/src/header.rs:968:28
```
This new code will handle all suffix not beginning with digit or dot.
Fixes to inline assmebly tests
* Join test thread to make assertion effective in sym.rs test case
* Use a single codegen unit to reduce non-determinism in srcloc.rs test #82886
Remove/replace some outdated crates from the dependency tree
- Remove `cloudabi` by updating `parking_lot` to 0.11.1.
- Replace `packed_simd` with `packed_simd2` by updating `bytecount` to 0.6.2.
Update cargo
12 commits in 90691f2bfe9a50291a98983b1ed2feab51d5ca55..1e8703890f285befb5e32627ad4e0a0454dde1fb
2021-03-16 21:36:55 +0000 to 2021-03-26 16:59:39 +0000
- tests: Tolerate "exit status" in error messages (rust-lang/cargo#9307)
- Default macOS targets to `unpacked` debuginfo (rust-lang/cargo#9298)
- Fix publication of packages with metadata and resolver (rust-lang/cargo#9300)
- Fix config includes not working. (rust-lang/cargo#9299)
- Emit note when `--future-incompat-report` had nothing to report (rust-lang/cargo#9263)
- RFC 3052: Stop including authors field in manifests made by cargo new (rust-lang/cargo#9282)
- Refactor feature handling, and improve error messages. (rust-lang/cargo#9290)
- Split out cargo-util package for cargo-test-support. (rust-lang/cargo#9292)
- Fix redundant_semicolons warning in resolver-tests. (rust-lang/cargo#9293)
- Use serde's error message option to avoid implementing `Deserialize`. (rust-lang/cargo#9237)
- Allow `cargo update` to operate with the --offline flag (rust-lang/cargo#9279)
- Fix typo in faq.md (rust-lang/cargo#9285)
Ban custom inner attributes in expressions and statements
Split out from https://github.com/rust-lang/rust/pull/82608
Custom inner attributes are unstable, so this won't break any stable users.
This allows us to speed up token collection, and avoid a redundant call to `collect_tokens_no_attrs` when parsing an `Expr` that has outer attributes.
r? `@petrochenkov`
Update char::escape_debug_ext to handle different escapes in strings and chars
Fixes#83046
The program
fn main() {
println!("{:?}", '"');
println!("{:?}", "'");
}
would previously print
'\"'
"\'"
With this patch it now prints:
'"'
"'"
Fixes#83046
The program
fn main() {
println!("{:?}", '"');
println!("{:?}", "'");
}
would previously print
'\"'
"\'"
With this patch it now prints:
'"'
"'"
Don't ICE when using `#[global_alloc]` on a non-item statement
Fixes#83469
We need to return an `Annotatable::Stmt` if we were passed an
`Annotatable::Stmt`
Refactor #82270 as lint instead of an error
This PR fixes several issues with #82270 which generated an error when `.intel_syntax` or `.att_syntax` was used in inline assembly:
- It is now a warn-by-default lint instead of an error.
- The lint only triggers on x86. `.intel_syntax` and `.att_syntax` are only valid on x86.
- The lint no longer provides machine-applicable suggestions for two reasons:
- These changes should not be made automatically since changes to assembly code can be very subtle.
- The template string is not always just a string: it can contain macro invocation (`concat!`), raw strings, escape characters, etc.
cc ``@asquared31415``
Rework rustdoc const type
This PR is mostly about two things:
1. Not storing some information in the `clean::Constant` type
2. Using `TyCtxt` in the formatting (which we will need in any case as we move forward in any case).
Also: I'm very curious of the perf change in here.
Thanks a lot `@danielhenrymantilla` for your `Captures` idea! It allowed me to solve the lifetime issue completely. :)
r? `@jyn514`
Refactor rustc_resolve::late::lifetimes to resolve per-item
There are some changes to tests that I'd like some feedback on; so this is still WIP.
The reason behind this change will (hopefully) allow us to (as part of #76814) be able to essentially use the lifetime resolve code to resolve *all* late bound vars (including those of super traits). Currently, it only resolves those that are *syntactically* in scope. In #76814, I'm essentially finding that I would essentially have to redo the passing of bound vars through scopes (i.e. when instantiating a poly trait ref), and that's what this code does anyways. However, to be able to do this (ask super traits what bound vars are in scope), we have to be able to resolve items separately.
The first commit is actually partially orthogonal. Essentially removing one use of late bound debruijn indices.
Not exactly sure who would be best to review here.
Let r? `@nikomatsakis`
coverage bug fixes and optimization support
Adjusted LLVM codegen for code compiled with `-Zinstrument-coverage` to
address multiple, somewhat related issues.
Fixed a significant flaw in prior coverage solution: Every counter
generated a new counter variable, but there should have only been one
counter variable per function. This appears to have bloated .profraw
files significantly. (For a small program, it increased the size by
about 40%. I have not tested large programs, but there is anecdotal
evidence that profraw files were way too large. This is a good fix,
regardless, but hopefully it also addresses related issues.
Fixes: #82144
Invalid LLVM coverage data produced when compiled with -C opt-level=1
Existing tests now work up to at least `opt-level=3`. This required a
detailed analysis of the LLVM IR, comparisons with Clang C++ LLVM IR
when compiled with coverage, and a lot of trial and error with codegen
adjustments.
The biggest hurdle was figuring out how to continue to support coverage
results for unused functions and generics. Rust's coverage results have
three advantages over Clang's coverage results:
1. Rust's coverage map does not include any overlapping code regions,
making coverage counting unambiguous.
2. Rust generates coverage results (showing zero counts) for all unused
functions, including generics. (Clang does not generate coverage for
uninstantiated template functions.)
3. Rust's unused functions produce minimal stubbed functions in LLVM IR,
sufficient for including in the coverage results; while Clang must
generate the complete LLVM IR for each unused function, even though
it will never be called.
This PR removes the previous hack of attempting to inject coverage into
some other existing function instance, and generates dedicated instances
for each unused function. This change, and a few other adjustments
(similar to what is required for `-C link-dead-code`, but with lower
impact), makes it possible to support LLVM optimizations.
Fixes: #79651
Coverage report: "Unexecuted instantiation:..." for a generic function
from multiple crates
Fixed by removing the aforementioned hack. Some "Unexecuted
instantiation" notices are unavoidable, as explained in the
`used_crate.rs` test, but `-Zinstrument-coverage` has new options to
back off support for either unused generics, or all unused functions,
which avoids the notice, at the cost of less coverage of unused
functions.
Fixes: #82875
Invalid LLVM coverage data produced with crate brotli_decompressor
Fixed by disabling the LLVM function attribute that forces inlining, if
`-Z instrument-coverage` is enabled. This attribute is applied to
Rust functions with `#[inline(always)], and in some cases, the forced
inlining breaks coverage instrumentation and reports.
FYI: `@wesleywiser`
r? `@tmandry`
Add documentation for rustdoc-gui tests
I think a bit of documentation doesn't hurt in this case considering how "out of the ordinary" this is.
r? ``@jyn514``
Remove Option::{unwrap_none, expect_none}.
This removes `Option::unwrap_none` and `Option::expect_none` since we're not going to stabilize them, see https://github.com/rust-lang/rust/issues/62633.
Closes#62633
Fixes#80691
When we evaluate a trait predicate, we convert an
`EvaluatedToOk` result to `EvaluatedToOkModuloRegions` if we erased any
regions. We cache the result under a region-erased 'freshened'
predicate, so `EvaluatedToOk` may not be correct for other predicates
that have the same cache key.
2229 migration: Don't try resolve regions before writeback
In the analysis use `resolve_vars_if_possible` instead of `fully_resolve`,
because we might not have performed regionck yet.
Fixes: #83176
r? `@nikomatsakis`
implement `feature(const_generics_defaults)`
Implements const generics defaults `struct Example<const N: usize=3>`, as well as a query for getting the default of a given const-parameter's def id. There are some remaining FIXME's but they were specified as not blocking for merging this PR. This also puts the defaults behind the unstable feature gate `#![feature(const_generics_defaults)]`.
~~This currently creates a field which is always false on `GenericParamDefKind` for future use when
consts are permitted to have defaults. I'm not sure if this is exactly what is best for adding default parameters, but I mimicked the style of type defaults, so hopefully this is ok.~~
r? `@lcnr`
Remove unnecessary `Option` wrapping around `Crate.module`
I'm wondering if it was originally there so that we could `take` the
module which enables `after_krate` to take an `&Crate`. However, the two
impls of `after_krate` only use `Crate.name`, so we can pass just the
name instead.
Slight visual improvements to warning boxes in the docs
First I noticed that sometimes the thumbs-down emoji in the docs is hard to see and hard to look at because the yellow emoji color and the color of the box below are so bright. Especially if you look at the screen late at night you can notice it. I thought I should change that so I added a black outline around the emoji. It works using the [`text-shadow`](https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow) property. It may be a bit hacky but it seems to work well and browser compatibility looks pretty good too: [browser compatibility](https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow#browser_compatibility).
For consistency the microscope has the black border too.
Alternatively I had `drop-shadow(0px 0px 1px black);` in mind but its [browser compatibility](https://developer.mozilla.org/en-US/docs/Web/CSS/filter-function/drop-shadow()#browser_compatibility) doesn't look as good and the blurry shadow probably doesn't look as good either.
Then, I thought that now that I'm at it I could also try changing the purple color to a color you would rather expect to see for deprecation: red. For the red I've taken the blue and reused it as a foundation and moved it to the red color spectrum.
But then I thought that the purple color could still be reused for something else: for the boxes that tell you about portability (e.g. _only supported on Unix_). These are currently blue.
I think blue doesn't really represent danger like it should. Not being cross-platform represents a danger because if you want to compile for a different platform, your code may not compile anymore. Blue looks too friendly and is in my opinion more suitable for a box containing general information like for instance "This is available since 1.0.0". None of the current three box types (unstable, deprecated and portability) are that.
I think purple is a better fit for it because it's kind of in the middle between "use it" and "don't use it". Deprecated is definitely "don't use it". To illustrate this better, here's a color spectrum:
Blue = friendly, "use it".
Red = danger, "don't use it".
And the purple in the middle (the color that the portability box now has) probably represents "use it if you have to", so it's not entirely friendly and not entirely a danger. That is why I think it fits.
However I made one change to that existing purple: I made the outer color a bit brighter because it's outstandingly dark compared to the other outer colors of the other boxes.
This is all subjective but in my opinion it looks nicer. At first you might need to get used to it though. Notice the box colors and the black outlines around the emoji shapes:
