Add provided methods `Seek::{stream_len, stream_position}`
This adds two new, provided methods to the `io::Seek` trait:
- `fn stream_len(&mut self) -> Result<u64>`
- `fn stream_position(&mut self) -> Result<u64>`
Both are added for convenience and to improve readability in user code. Reading `file.stream_len()` is much better than to manually seek two or three times. Similarly, `file.stream_position()` is much more clear than `file.seek(SeekFrom::Current(0))`.
You can find prior discussions [in this internals thread](https://internals.rust-lang.org/t/pre-rfc-idea-extend-io-seek-with-convenience-methods-with-e-g-stream-len/9262). I think I addressed all concerns in that thread.
I already wrote three RFCs to add a small new API to libstd but I noticed that many public changes to libstd happen without an RFC. So I figured I can try opening a PR directly without going through RFCs first. After all, we do have rfcbot here too. If you think this change is too big to merge without an RFC, I can still close this PR and write an RFC.
The pause instruction requires SSE2 but was being unconditionally used
on targets without it, resulting in undefined behavior.
This PR fixes that by only using the pause intrinsic if SSE2 is available.
It also removes the inline assembly which was not required since these
instructions are available in core::arch, and extends support of
the spin_loop hint to arm targets with the v6 feature which also
support the yield instruction.
Closes#59237 .
Add new test case for possible bug in BufReader
When reading a large chunk from a BufReader, if all the bytes from the buffer have been already consumed, the internal buffer is bypassed entirely. However, it is not invalidated, and it's possible to access its contents using the `seek_relative` method, because it tries to reuse the existing buffer.
Fixes for the generator transform
* Moves cleanup annotations in pretty printed MIR so that they can be tested
* Correctly determines which drops are in cleanup blocks when elaborating generator drops
* Use the correct state for poisoning a generator
Closes#58892
Rework how bootstrap tools are built
This makes bootstrap tools buildable and testable in stage 0 with the downloaded bootstrap compiler, futhermore, it makes it such that they cannot be built in any other stage.
Notably, this will also mean that compiletest may need to wait a cycle before it can use changes to `libtest`, as it no longer depends on the in-tree libtest.
Introduce assembly tests suite
The change introduces a new test suite - **Assembly** tests. The motivation behind this is an ability to perform end-to-end codegen testing with LLVM backend. Turned out, NVPTX backend sometimes missing common Rust features (`i128` and libcalls in the past, and still full atomics support) due to different reasons.
Prior to this change, basic NVPTX assembly tests were implemented within `run-make` suite. Now, it's easier to write additional and maintain existing tests for the target.
cc @gnzlbg @peterhj
cc @eddyb I adjusted mangling scheme expectation, so there is no need to change the tests for #57967
Keep last redundant linker flag, not first
When a library (L1) is passed to the linker multiple times, this is sometimes purposeful: there might be several other libraries in the linker command (L2 and L3) that all depend on L1. You'd end up with a (simplified) linker command that looks like:
```
-l2 -l1 -l3 -l1
```
With the previous behavior, when rustc encountered a redundant library, it would keep the first instance, and remove the later ones, resulting in:
```
-l2 -l1 -l3
```
This can cause a linker error, because on some platforms (e.g. Linux), the linker will only include symbols from L1 that are needed *at the point it's referenced in the command line*. So if L3 depends on additional symbols from L1, which aren't needed by L2, the linker won't know to include them, and you'll end up with "undefined symbols" errors.
A better behavior is to keep the *last* instance of the library:
```
-l2 -l3 -l1
```
This ensures that all "downstream" libraries have been included in the linker command before the "upstream" library is referenced.
Fixes rust-lang#47989
Rollup of 5 pull requests (all of which changes `src/ci/docker`)
Successful merges:
- #58986 ([CI] Update binutils for powerpc64 and powerpc64le)
- #59038 (Track embedded-book in the toolstate)
- #59055 (CI: Set job names.)
- #59253 (Calculate Docker cache hash precisely from Dockerfile's dependencies)
- #59257 (Update CI configuration for building Redox libraries)
Failed merges:
r? @ghost
