This is necessary if we want to implement `[T]::align_to` and is more
useful in general.
This implementation effort has begun during the All Hands and represents
a month of my futile efforts to do any sort of maths. Luckily, I
found the very very nice Chris McDonald (cjm) on IRC who figured out the
core formulas for me! All the thanks for existence of this PR go to
them!
Anyway… Those formulas were mangled by yours truly into the arcane forms
you see here to squeeze out the best assembly possible on most of the
modern architectures (x86 and ARM were evaluated in practice). I mean,
just look at it: *one actual* modulo operation and everything else is
just the cheap single cycle ops! Admitedly, the naive solution might be
faster in some common scenarios, but this code absolutely butchers the
naive solution on the worst case scenario.
Alas, the result of this arcane magic also means that the code pretty
heavily relies on the preconditions holding true and breaking those
preconditions will unleash the UB-est of all UBs! So don’t.
Switch to bootstrapping from 1.27
It's possible the Float trait could be removed from core, but I couldn't tell whether it was intended to be removed or not. @SimonSapin may be able to comment more here; we can presumably also do that in a follow up PR as this one is already quite large.
In #49289, rustc was changed to emit metadata for binaries, which made
it so that the librustc.rmeta file created when compiling librustc was
overwritten by the rustc-main compilation. This commit renames the
rustc-main binary to avoid this problem.
https://github.com/rust-lang/cargo/issues/5524 has also been filed to
see if Cargo can learn to warn on this situation instead of leaving it
for the user to debug.
compiletest: Run revisions as independent tests.
Fixes#47604.
- The output of each test is now in its own directory.
- "auxiliary" output is now under the respective test directory.
- `stage_id` removed from filenames, and instead placed in the stamp file as a hash. This helps keep path lengths down for Windows.
In brief, the new layout looks like this:
```
<build_base>/<relative_dir>/<testname>.<revision>.<mode>/
stamp
<testname>.err
<testname>.out
a (binary)
auxiliary/lib<auxname>.dylib
auxiliary/<auxname>/<auxname>.err
auxiliary/<auxname>/<auxname>.out
```
(revision and mode are optional)
- The output of each test is now in its own directory.
- "auxiliary" output is now under the respective test directory.
- `stage_id` removed from filenames, and instead placed in the stamp file as a hash. This helps keep path lengths down for Windows.
In brief, the new layout looks like this:
```
<build_base>/<relative_dir>/<testname>.<revision>.<mode>/
stamp
<testname>.err
<testname>.out
a (binary)
auxiliary/lib<auxname>.dylib
auxiliary/<auxname>/<auxname>.err
auxiliary/<auxname>/<auxname>.out
```
(revision and mode are optional)
rustc: Fix `crate` lint for single-item paths
This commit fixes recommending the `crate` prefix when migrating to 2018 for
paths that look like `use foo;` or `use {bar, baz}`
Closes#50660
Rollup of 17 pull requests
Successful merges:
- #50170 (Implement From for more types on Cow)
- #50638 (Don't unconditionally set CLOEXEC twice on every fd we open on Linux)
- #50656 (Fix `fn main() -> impl Trait` for non-`Termination` trait)
- #50669 (rustdoc: deprecate `#![doc(passes, plugins, no_default_passes)]`)
- #50726 (read2: Use inner function instead of closure)
- #50728 (Fix rustdoc panic with `impl Trait` in type parameters)
- #50736 (env: remove unwrap in examples in favor of try op)
- #50740 (Remove LazyBTreeMap.)
- #50752 (Add missing error codes in libsyntax-ext asm)
- #50779 (Make mutable_noalias and arg_align_attributes be tracked)
- #50787 (Fix run-make wasm tests)
- #50788 (Fix an ICE when casting a nonexistent const)
- #50789 (Ensure libraries built in stage0 have unique metadata)
- #50793 (tidy: Add a check for empty UI test files)
- #50797 (fix a typo in signed-integer::from_str_radix())
- #50808 (Stabilize num::NonZeroU*)
- #50809 (GitHub: Stop treating Cargo.lock as a generated file.)
Failed merges:
This patch changes `opt_normalize_project_type` so it appends
obligations to a given obligations vector, instead of returning a new
obligations vector.
This change avoids lots of allocations. In the most extreme case, for a
clean "Check" build of serde it reduces the total number of allocations
by 20%.
There is a hot path through `opt_normalize_projection_type`:
- `try_start` does a cache lookup (#1).
- The result is a `NormalizedTy`.
- There are no unresolved type vars, so we call `complete`.
- `complete` does *another* cache lookup (#2), then calls
`SnapshotMap::insert`.
- `insert` does *another* cache lookup (#3), inserting the same value
that's already in the cache.
This patch optimizes this hot path by introducing `complete_normalized`,
for use when the value is known in advance to be a `NormalizedTy`. It
always avoids lookup #2. Furthermore, if the `NormalizedTy`'s
obligations are empty (the common case), we know that lookup #3 would be
a no-op, so we avoid it, while inserting a Noop into the `SnapshotMap`'s
undo log.
Implement From for more types on Cow
This is basically https://github.com/rust-lang/rust/pull/48191, except that it should be implemented in a way that doesn't break third party crates.
tidy: Add a check for empty UI test files
Check for empty `.stderr` and `.stdout` files in UI test directories.
Empty files could still pass testing for `compile-pass` tests with no output
so they can get into the repo accidentally, but they are not necessary and can
be removed.
This is very much an in progress pull request. I'm having an issue with rustfmt. It wanted to reformat the entire file for almost every file by default. And when I run tidy it just errors out because it catches the empty files that are already in the repo.
My next step is goin got be to remove those empty file and see if running tidy again will actually reformat things outside of the context of `cargo fmt`
Fixes https://github.com/rust-lang/rust/issues/50785
Ensure libraries built in stage0 have unique metadata
Issue #50786 shows a case with local rebuild where the libraries built
by stage0 had the same suffix as stage0's own, and were accidentally
loaded by that stage0 rustc when compiling `librustc_trans`.
Now we set `__CARGO_DEFAULT_LIB_METADATA` to "bootstrap" during stage0,
rather than the release channel like usual, so the library suffix will
always be completely distinct from the stage0 compiler.
Remove LazyBTreeMap.
It was introduced in #50240 to avoid an allocation when creating a new
BTreeMap, which gave some speed-ups. But then #50352 made that the
default behaviour for BTreeMap, so LazyBTreeMap is no longer necessary.
