Add new EFIAPI ABI
Fixes#54527
Adds a new ABI, "efiapi", which reflects the calling convention as specified by [the current spec UEFI spec](https://uefi.org/sites/default/files/resources/UEFI%20Spec%202_7_A%20Sept%206.pdf#G6.999903). When compiling for x86_64, we should select the `win64` ABI, while on all other architectures (Itanium, x86, ARM and ARM64 and RISC-V), we should select the `C` ABI.
Currently, this is done by just turning it into the C ABI everywhere except on x86_64, where it's turned into the win64 ABI. Should we prevent this ABI from being used on unsupported architectures, and if so, how would this be done?
Lint ignored `#[inline]` on function prototypes
Fixes https://github.com/rust-lang/rust/issues/51280.
- Adds a `unused_attribute` lint for `#[inline]` on function prototypes.
- As a consequence, foreign items, impl items and trait items now have their attributes checked, which could cause some code to no longer compile (it was previously erroneously ignored).
Stabilize `const_constructor`
# Stabilization proposal
I propose that we stabilize `#![feature(const_constructor)]`.
Tracking issue: https://github.com/rust-lang/rust/issues/61456
Version target: 1.40 (2019-11-05 => beta, 2019-12-19 => stable).
## What is stabilized
### User guide
Tuple struct and tuple variant constructors are now considered to be constant functions. As such a call expression where the callee has a tuple struct or variant constructor "function item" type can be called:
```rust
const fn make_options() {
// These already work because they are special cased:
Some(0);
(Option::Some)(1);
// These also work now:
let f = Option::Some;
f(2);
{Option::Some}(3);
<Option<_>>::Some(5);
}
```
### Motivation
Consistency with other `const fn`. Consistency between syntactic path forms.
This should also ensure that constructors implement `const Fn` traits and can be coerced to `const fn` function pointers, if they are introduced.
## Tests
* [ui/consts/const_constructor/const-construct-call.rs](0d75ab2293/src/test/ui/consts/const_constructor/const-construct-call.rs) - Tests various syntactic forms, use in both `const fn` and `const` items, and constructors in both the current and extern crates.
* [ui/consts/const_constructor/const_constructor_qpath.rs](1850dfcdab/src/test/ui/consts/const_constructor/const_constructor_qpath.rs) - Tests that type qualified paths to enum variants are also considered to be `const fn`.(#64247)
r? @oli-obk
Closes#61456
Closes #64247
libsyntax: Enhance documentation of the AST module
This PR enhances documentation state to the `libsyntax/ast.rs` (as initiative caused by [rustc-guide#474](https://github.com/rust-lang/rustc-guide/issues/474)), by adding:
- Module documentation.
- Doc-comments (and a bit of usual comments) in non-obvious (as for me) places.
- Minor style fixes to improve module readability.
Adds a new ABI for the EFIAPI calls. This ABI should reflect the latest
version of the UEFI specification at the time of commit (UEFI spec 2.8,
URL below). The specification says that for x86_64, we should follow the
win64 ABI, while on all other supported platforms (ia32, itanium, arm,
arm64 and risc-v), we should follow the C ABI.
To simplify the implementation, we will simply follow the C ABI on all
platforms except x86_64, even those technically unsupported by the UEFI
specification.
https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf
Fix the start/end byte positions in the compiler JSON output
Track the changes made during normalization in the `SourceFile` and use this information to correct the `start_byte` and `end_byte` fields in the JSON output.
This should ensure the start/end byte fields can be used to index the original file, even if Rust normalized the source code for parsing purposes. Both CRLF to LF and BOM removal are handled with this one.
The rough plan was discussed with @matklad in rust-lang-nursery/rustfix#176 - although I ended up going with `u32` offset tracking so I wouldn't need to deal with `u32 + i32` arithmetics when applying the offset to the span byte positions.
Fixes#65029
Derive `Rustc{En,De}codable` for `TokenStream`.
`TokenStream` used to be a complex type, but it is now just a newtype
around a `Lrc<Vec<TreeAndJoint>>`. Currently it uses custom encoding
that discards the `IsJoint` and custom decoding that adds `NonJoint`
back in for every token tree. This requires building intermediate
`Vec<TokenTree>`s.
This commit makes `TokenStream` derive `Rustc{En,De}codable`. This
simplifies the code, and avoids the creation of the intermediate
vectors, saving up to 3% on various benchmarks. It also changes the AST
JSON output in one test.
r? @petrochenkov
