Implement another internal lints
cc #49509
This adds ~~two~~ one internal lint~~s~~:
1. LINT_PASS_IMPL_WITHOUT_MACRO: Make sure, that the `{declare,impl}_lint_pass` macro is used to implement lint passes. cc #59669
2. ~~USAGE_OF_TYCTXT_AND_SPAN_ARGS: item 2 on the list in #49509~~
~~With 2. I wasn't sure, if this lint should be applied everywhere. That means a careful review of 0955835 would be great. Also 73fb9b4 allows this lint on some functions. Should I also apply this lint there?~~
TODO (not directly relevant for review):
- [ ] https://github.com/rust-lang/rust/pull/59316#discussion_r280186517 (not sure yet, if this works or how to query for `rustc_private`, since it's not in [`Features`](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/feature_gate/struct.Features.html) 🤔 cc @eddyb)
- [x] https://github.com/rust-lang/rust/pull/61735#discussion_r292389870
- [x] Check explicitly for the `{declare,impl}_lint_pass!` macros
r? @oli-obk
Stabilize support for Profile-guided Optimization
This PR makes profile-guided optimization available via the `-C profile-generate` / `-C profile-use` pair of commandline flags and adds end-user documentation for the feature to the [rustc book](https://doc.rust-lang.org/rustc/). The PR thus ticks the last two remaining checkboxes of the [stabilization tracking issue](https://github.com/rust-lang/rust/issues/59913).
From the tracking issue:
> Profile-guided optimization (PGO) is a common optimization technique for ahead-of-time compilers. It works by collecting data about a program's typical execution (e.g. probability of branches taken, typical runtime values of variables, etc) and then uses this information during program optimization for things like inlining decisions, machine code layout, or indirect call promotion.
If you are curious about how this can be used, there is a rendered version of the documentation this PR adds available [here](
https://github.com/michaelwoerister/rust/blob/stabilize-pgo/src/doc/rustc/src/profile-guided-optimization.md).
r? @alexcrichton
cc @rust-lang/compiler
Fix meta-variable binding errors in macros
The errors are either:
- The meta-variable used in the right-hand side is not bound (or defined) in the
left-hand side.
- The meta-variable used in the right-hand side does not repeat with the same
kleene operator as its binder in the left-hand side. Either it does not repeat
enough, or it uses a different operator somewhere.
This change should have no semantic impact.
Found by https://github.com/rust-lang/rust/pull/62008
The errors are either:
- The meta-variable used in the right-hand side is not bound (or defined) in the
left-hand side.
- The meta-variable used in the right-hand side does not repeat with the same
kleene operator as its binder in the left-hand side. Either it does not repeat
enough, or it uses a different operator somewhere.
This change should have no semantic impact.
`ByRef` const values have no identity beyond their value, we should not treat them as having identity. The `AllocId` often differed between equal constants, because of the way that the miri-engine evaluates constants.
Refactor C FFI variadics to more closely match their C counterparts, and add Clone implementation
We had to make some changes to expose `va_copy` and `va_end` directly to users (mainly for C2Rust, but not exclusively):
- redefine the Rust variadic structures to more closely correspond to C: `VaList` now matches `va_list`, and `VaListImpl` matches `__va_list_tag`
- add `Clone` for `VaListImpl`
- add explicit `as_va_list()` conversion function from `VaListImpl` to `VaList`
- add deref coercion from `VaList` to `VaListImpl`
- add support for the `asmjs` target
All these changes were needed for use cases like:
```Rust
let mut ap2 = va_copy(ap);
vprintf(fmt, ap2);
va_end(&mut ap2);
```
librustc_codegen_llvm: Use repr(transparent) for bitflags over repr(C…
…) (#61306)
In order to make sure that Rust's bitflags types are passed the same way in the Rust ABI as they are in the C ABI, we need to use the attribute repr(transparent) over the repr(C) attribute for the single-field bitflags structs in in order to prevent ABI mismatches. Thanks to Michael Karcher for finding this bug.
In order to make sure that Rust's bitflags types are passed the same
way in the Rust ABI as they are in the C ABI, we need to use the attribute
repr(transparent) over the repr(C) attribute for the single-field bitflags
structs in in order to prevent ABI mismatches. Thanks to Michael Karcher
for finding this bug.
add support for unchecked math
add compiler support for
```rust
/// Returns the result of an unchecked addition, resulting in
/// undefined behavior when `x + y > T::max_value()` or `x + y < T::min_value()`.
pub fn unchecked_add<T>(x: T, y: T) -> T;
/// Returns the result of an unchecked substraction, resulting in
/// undefined behavior when `x - y > T::max_value()` or `x - y < T::min_value()`.
pub fn unchecked_sub<T>(x: T, y: T) -> T;
/// Returns the result of an unchecked multiplication, resulting in
/// undefined behavior when `x * y > T::max_value()` or `x * y < T::min_value()`.
pub fn unchecked_mul<T>(x: T, y: T) -> T;
```
cc https://github.com/rust-lang/rfcs/issues/2508
