Add MIR Optimization Tests
I've starting working on the infrastructure for testing MIR optimizations.
The plan now is to have a set of test cases (written in Rust), compile them with -Z dump-mir, and check the MIR before and after each pass.
feat: reinterpret `precision` field for strings
This commit changes the behavior of formatting string arguments with both width and precision fields set.
Documentation says that the `width` field is the "minimum width" that the format should take up. If the value's string does not fill up this many characters, then the padding specified by fill/alignment will be used to take up the required space.
This is true for all formatted types except string, which is truncated down to `precision` number of chars and then all of `fill`, `align` and `width` fields are completely ignored.
For example: `format!("{:/^10.8}", "1234567890);` emits "12345678". In the contrast Python version works as the expected:
```python
>>> '{:/^10.8}'.format('1234567890')
'/12345678/'
```
This commit gives back the `Python` behavior by changing the `precision` field meaning to the truncation and nothing more. The result string *will* be prepended/appended up to the `width` field with the proper `fill` char.
__However, this is the breaking change, I admit.__ Feel free to close it, but otherwise it should be mentioned in the `std::fmt` documentation somewhere near of `fill/align/width` fields description.
rustc: Remove soft-float from MIPS targets
Right now two MIPS targets in the compiler, `mips-unknown-linux-{gnu,musl}` both
generate object files using the soft-float ABI through LLVM by default. This is
also expressed as the `-C soft-float` codegen option and otherwise isn't used
for any other target in the compiler. This option was added quite some time ago
(back in #9617), and nowadays it's more appropriate to be done through a codegen
option.
This is motivated by #34743 which necessitated an upgrade in the CMake
installation on our bots which necessitated an upgrade in the Ubuntu version
which invalidated the MIPS compilers we were using. The new MIPS compilers
(coming from Debian I believe) all have hard float enabled by default and soft
float support not built in. This meant that we couldn't upgrade the bots
until #34841 landed because otherwise we would fail to compile C code as the
`-msoft-float` option wouldn't work.
Unfortunately, though, this means that once we upgrade the bots the C code we're
compiling will be compiled for hard float and the Rust code will be compiled
for soft float, a bad mismatch! This PR remedies the situation such that Rust
will compile with hard float as well.
If this lands it will likely produce broken nightlies for a day or two while we
get around to upgrading the bots because the current C toolchain only produces
soft-float binaries, and now rust will be hard-float. Hopefully, though, the
upgrade can go smoothly!
implement AddAssign for String
Currently `String` implements `Add` but not `AddAssign`. This PR fills in that gap.
I played around with having `AddAssign` (and `Add` and `push_str`) take `AsRef<str>` instead of `&str`, but it looks like that breaks arguments that implement `Deref<Target=str>` and not `AsRef<str>`. Comments in [`libcore/convert.rs`](https://github.com/rust-lang/rust/blob/master/src/libcore/convert.rs#L207-L213) make it sound like we could fix this with a blanket impl eventually. Does anyone know what's blocking that?
core: impl From<T> for Option<T>
First, the semantics of this `impl` seem spot on. If I have a value `T`, and I wish to make a `Option<T>`, then `Option::from(val)` should always give `Some(val)`.
Second, this allows improvement for several APIs that currently take `Option<T>` as arguments. Consider:
```rust
fn set_read_timeout(&mut self, timeout: Option<u32>) {
// ...
}
x.set_read_timeout(Some(30));
x.set_read_timeout(Some(10));
x.set_read_timeout(None);
```
With this `impl`:
```rust
fn set_read_timeout<T: Into<Option<u32>>>(&mut self, timeout: T) {
let timeout = timeout.into();
// ...
}
x.set_read_timeout(30);
x.set_read_timeout(10);
x.set_read_timeout(Some(10)); // backwards compatible
x.set_read_timeout(None);
```
The change to those methods aren't included, but could be modified later.
r? @sfackler
mk: Stop using cmake for compiler-rt
The compiler-rt build system has been a never ending cause of pain for Rust
unfortunately:
* The build system is very difficult to invoke and configure to only build
compiler-rt, especially across platforms.
* The standard build system doesn't actually do what we want, not working for
some of our platforms and requiring a significant number of patches on our end
which are difficult to apply when updating compiler-rt.
* Compiling compiler-rt requires LLVM to be compiled, which... is a big
dependency! This also means that over time compiler-rt is not guaranteed to
build against older versions of LLVM (or newer versions), and we often want to
work with multiple versions of LLVM simultaneously.
The makefiles and rustbuild already know how to compile C code, the code here is
far from the *only* C code we're compiling. This patch jettisons all logic to
work with compiler-rt's build system and just goes straight to the source. We
just list all files manually (copied from compiler-rt's
lib/builtins/CMakeLists.txt) and compile them into an archive.
It's likely that this means we'll fail to pick up new files when we upgrade
compiler-rt, but that seems like a much less significant cost to pay than what
we're currently paying.
cc #34400, first steps towards that
The compiler-rt build system has been a never ending cause of pain for Rust
unfortunately:
* The build system is very difficult to invoke and configure to only build
compiler-rt, especially across platforms.
* The standard build system doesn't actually do what we want, not working for
some of our platforms and requiring a significant number of patches on our end
which are difficult to apply when updating compiler-rt.
* Compiling compiler-rt requires LLVM to be compiled, which... is a big
dependency! This also means that over time compiler-rt is not guaranteed to
build against older versions of LLVM (or newer versions), and we often want to
work with multiple versions of LLVM simultaneously.
The makefiles and rustbuild already know how to compile C code, the code here is
far from the *only* C code we're compiling. This patch jettisons all logic to
work with compiler-rt's build system and just goes straight to the source. We
just list all files manually (copied from compiler-rt's
lib/builtins/CMakeLists.txt) and compile them into an archive.
It's likely that this means we'll fail to pick up new files when we upgrade
compiler-rt, but that seems like a much less significant cost to pay than what
we're currently paying.
cc #34400, first steps towards that
Add IpAddr common methods
Per https://github.com/rust-lang/rfcs/pull/1668#issuecomment-230867962 no RFC is needed here.
The generated documentation for these methods is being weird. It shows a deprecation message referencing #27709 for each of them even though two of the referenced methods were stabilized as part of that issue. I don't know how best to address that.
Add some warnings to std::env::current_exe
/cc #21889 @rust-lang/libs @semarie
I started writing this up. I'm not sure if we want to go into other things and in what depth; we don't currently have a lot of security-specific documentation to model after.
Thoughts?
Retry on EINTR in Bytes and Chars.
>Since Bytes and Chars called directly into Read::read, they didn't use any of the retrying wrappers. This allows both iterator types to retry.
