Add `format_args_capture` feature
This is the initial implementation PR for [RFC 2795](https://github.com/rust-lang/rfcs/pull/2795).
Note that, as dicussed in the tracking issue (#67984), the feature gate has been called `format_args_capture`.
Next up I guess I need to add documentation for this feature. I've not written any docs before for rustc / std so I would appreciate suggestions on where I should add docs.
Fix handling of reserved registers for ARM inline asm
`r6` is now disallowed as an operand since LLVM sometimes uses it as a base pointer.
The check against using the frame pointer as an operand now takes the platform into account and will block either `r7` or `r11` as appropriate.
Fixes#73450
cc @cbiffle
Diagnose use of incompatible sanitizers
Emit an error when incompatible sanitizer are configured through command
line options. Previously the last one configured prevailed and others
were silently ignored.
Additionally use a set to represent configured sanitizers, making it
possible to enable multiple sanitizers at once. At least in principle,
since currently all of them are considered to be incompatible with
others.
asm: Allow multiple template string arguments; interpret them as newline-separated
Allow the `asm!` macro to accept a series of template arguments, and interpret them as if they were concatenated with a '\n' between them. This allows writing an `asm!` where each line of assembly appears in a separate template string argument.
This syntax makes it possible for rustfmt to reliably format and indent each line of assembly, without risking changes to the inside of a template string. It also avoids the complexity of having the user carefully format and indent a multi-line string (including where to put the surrounding quotes), and avoids the extra indentation and lines of a call to `concat!`.
For example, rewriting the second example from the [blog post on the new inline assembly syntax](https://blog.rust-lang.org/inside-rust/2020/06/08/new-inline-asm.html) using multiple template strings:
```rust
fn main() {
let mut bits = [0u8; 64];
for value in 0..=1024u64 {
let popcnt;
unsafe {
asm!(
" popcnt {popcnt}, {v}",
"2:",
" blsi rax, {v}",
" jz 1f",
" xor {v}, rax",
" tzcnt rax, rax",
" stosb",
" jmp 2b",
"1:",
v = inout(reg) value => _,
popcnt = out(reg) popcnt,
out("rax") _, // scratch
inout("rdi") bits.as_mut_ptr() => _,
);
}
println!("bits of {}: {:?}", value, &bits[0..popcnt]);
}
}
```
Note that all the template strings must appear before all other arguments; you cannot, for instance, provide a series of template strings intermixed with the corresponding operands.
Emit an error when incompatible sanitizer are configured through command
line options. Previously the last one configured prevailed and others
were silently ignored.
Additionally use a set to represent configured sanitizers, making it
possible to enable multiple sanitizers at once. At least in principle,
since currently all of them are considered to be incompatible with
others.
Suggest including unused asm arguments in a comment to avoid error
We require all arguments to an `asm!` to be used in the template string, just like format strings. However in some cases (e.g. `black_box`) it may be desirable to have `asm!` arguments that are not used in the template string.
Currently this is a hard error rather than a lint since `#[allow]` does not work on macros (#63221), so this PR suggests using the unused arguments in an asm comment as a workaround.
r? @petrochenkov
Update books
## nomicon
3 commits in d1517d4e3f29264c5c67bce2658516bb5202c800..bfe1ab96d717d1dda50e499b360f2e2f57e1750a
2020-05-12 13:47:00 -0400 to 2020-06-05 13:19:42 -0400
- Clarify that str data must still be initialized
- Remove language-level UB for non-UTF-8 str
- fix Nomicon transmute UB
## reference
5 commits in becdca9477c9eafa96a4eea5156fe7a2730d9dd2..5d40ba5c2515caffa7790cda621239dc21ef5a72
2020-05-21 21:08:02 +0100 to 2020-06-06 20:25:36 -0700
- Add some links to Disambiguating Function Calls. (rust-lang-nursery/reference#829)
- change bash to sh as shell code blocks language indentifier (rust-lang-nursery/reference#827)
- Fix sentence mistake in array-expr.md (rust-lang-nursery/reference#826)
- removed the word "Second" form the beginning of the 2nd list item and labelled it as `2` (rust-lang-nursery/reference#822)
- Update fn-like proc-macro invocation restrictions. (rust-lang-nursery/reference#816)
## book
14 commits in e8a4714a9d8a6136a59b8e63544e149683876e36..30cd9dfe71c446de63826bb4472627af45acc9db
2020-05-25 10:29:27 -0500 to 2020-06-07 23:07:19 -0500
- Unnecessarily long type name in Ch 13 (rust-lang/book#2362)
- Tweak example in chapter 10 (rust-lang/book#2363)
- Mention that to_lowercase isn't perfect (rust-lang/book#2364)
- fix typo in CONTRIBUTING.md (rust-lang/book#2360)
- Link German translation in appendix F (rust-lang/book#2347)
- Updates wording on Box example (rust-lang/book#2332)
- fix: match 15-24 with 15-18 (rust-lang/book#2324)
- Reword ch01-03 recap paragraph (rust-lang/book#2305)
- Remove some confusing wording. (rust-lang/book#2358)
- Clarify some wording a bit (rust-lang/book#2357)
- Update ch12-05 PowerShell note (rust-lang/book#2348)
- text -> console (rust-lang/book#2352)
- Improve wording around drop (rust-lang/book#2350)
- Make some statements about crates more correct (rust-lang/book#2349)
## edition-guide
1 commits in 0a8ab5046829733eb03df0738c4fafaa9b36b348..82bec5877c77cfad530ca11095db4456d757f668
2020-05-18 08:34:23 -0500 to 2020-06-03 08:56:02 -0500
- Add stuff for Rust 1.33 (rust-lang/edition-guide#214)
Free `default()` forwarding to `Default::default()`
It feels a bit redundant to have to say `Default::default()` every time I need a new value of a type that has a `Default` instance.
Especially so, compared to Haskell, where the same functionality is called `def`.
Providing a free `default()` function that forwards to `Default::default()` seems to improve the situation.
The trait is still there, so if someone wants to be explicit and to say `Default::default()` - it still works, but if imported as `std::default::default;`, then the free function reduces typing and visual noise.
Fix documentation example for gcov profiling
closes#72546
Improves the documentation for the unstable Rustflag `-Zprofile` by:
- stating that Incremental compilation must be turned off.
- Adding the other `RUSTFLAGS` that should/need to be turned on (taken from [grcov documentation](https://github.com/mozilla/grcov#example-how-to-generate-gcda-files-for-a-rust-project))
- Mentioning `RUSTC_WRAPPER` to prevent everything getting instrumented.
r? @steveklabnik
