Yet another attempt to make the prose on the std crate page
clearer and more informative.
This does a lot of things: tightens up the opening, adds useful links
(including a link to the search bar), offers guidance on how to use
the docs, and expands the prelude docs as a useful newbie entrypoint.
... matching the existing Index impls.
There is no reason not to if String implement DerefMut.
The code removed in `src/librustc/middle/effect.rs` was added in #9750
to prevent things like `s[0] = 0x80` where `s: String`,
but I belive became unnecessary when the Index(Mut) traits were introduced.
TLS tests have been deadlocking on the OSX bots for quite some time now and this
commit is the result of the investigation into what's going on. It turns out
that a value in TLS which is being destroyed (e.g. the destructor is run) can be
reset back to the initial state **while the destructor is running** if TLS is
re-accessed.
To fix this we stop calling drop_in_place on OSX and instead move the data to a
temporary location on the stack.
TLS tests have been deadlocking on the OSX bots for quite some time now and this
commit is the result of the investigation into what's going on. It turns out
that a value in TLS which is being destroyed (e.g. the destructor is run) can be
reset back to the initial state **while the destructor is running** if TLS is
re-accessed.
To fix this we stop calling drop_in_place on OSX and instead move the data to a
temporary location on the stack.
Use escaped byte string representation for CString Debug
Faithfully represent the contents of the CString and CStr in their Debug
impl, by treating them as byte strings with our default escaping to
ascii representation.
Add impl Debug for CStr.
Fixes#26964.
Faithfully represent the contents of the CString and CStr in their Debug
impl, by treating them as byte strings with our default escaping to
ascii representation.
Add impl Debug for Cstr.
Fixes#26964.
Previously on Windows a directory junction would return false from `is_dir`,
causing various odd behavior, specifically calls to `create_dir_all` might fail
when they would otherwise continue to succeed.
Closes#26716
This makes `Debug` for `File` show the file path and access mode of the file on OS X, just like on Linux.
I'd be happy about any feedback how to make this code better. In particular, I'm not sure how to handle the buffer passed to `fnctl`. This way works, but it feels a bit cumbersome. `fcntl` unfortunately doesn't return the length of the path.
Previously on Windows a directory junction would return false from `is_dir`,
causing various odd behavior, specifically calls to `create_dir_all` might fail
when they would otherwise continue to succeed.
Closes#26716
This allows CString and CStr to be used with the Cow type,
which is extremely useful when interfacing with C libraries
that make extensive use of C-style strings.
This allows CString and CStr to be used with the Cow type,
which is extremely useful when interfacing with C libraries
that make extensive use of C-style strings.
I find that isn't supported on the current API and I think is necesary.
It is my first PR to rust (I'm not a rust expert and I'm not sure if this is the better way to propose this thinks), of course any suggestion of change will be welcome.
I'm almost sure that in windows aren't supported this filetypes, then, i put in the api of win::fs the functions with a fixed false in the response, I hope this is correct.
In a followup to PR #26849, improve one more location for I/O where
we can use `Vec::resize` to ensure better performance when zeroing
buffers.
Use the `vec![elt; n]` macro everywhere we can in the tree. It replaces
`repeat(elt).take(n).collect()` which is more verbose, requires type
hints, and right now produces worse code. `vec![]` is preferable for vector
initialization.
The `vec![]` replacement touches upon one I/O path too, Stdin::read
for windows, and that should be a small improvement.
r? @alexcrichton
The common pattern `iter::repeat(elt).take(n).collect::<Vec<_>>()` is
exactly equivalent to `vec![elt; n]`, do this replacement in the whole
tree.
(Actually, vec![] is smart enough to only call clone n - 1 times, while
the former solution would call clone n times, and this fact is
virtually irrelevant in practice.)
Improve zerofill in Vec::resize and Read::read_to_end
We needed a more efficient way to zerofill the vector in read_to_end.
This to reduce the memory intialization overhead to a minimum.
Use the implementation of `std::vec::from_elem` (used for the vec![]
macro) for Vec::resize as well. For simple element types like u8, this
compiles to memset, so it makes Vec::resize much more efficient.
Use the vec![] macro directly to create a sized, zeroed vector.
This should result in a big speedup when creating BufReader, because
vec![0; cap] compiles to a memset call, while the previous extend code
currently did not.
We needed a more efficient way to zerofill the vector in read_to_end.
This to reduce the memory intialization overhead to a minimum.
Use the implementation of `std::vec::from_elem` (used for the vec![]
macro) for Vec::resize as well. For simple element types like u8, this
compiles to memset, so it makes Vec::resize much more efficient.
This PR was originally going to be a "let's start running tests on MSVC" PR, but it didn't quite get to that point. It instead gets us ~80% of the way there! The steps taken in this PR are:
* Landing pads are turned on by default for 64-bit MSVC. The LLVM support is "good enough" with the caveat the destructor glue is now marked noinline. This was recommended [on the associated bug](https://llvm.org/bugs/show_bug.cgi?id=23884) as a stopgap until LLVM has a better representation for exception handling in MSVC. The consequence of this is that MSVC will have a bit of a perf hit, but there are possible routes we can take if this workaround sticks around for too long.
* The linker (`link.exe`) is now looked up in the Windows Registry if it's not otherwise available in the environment. This improves using the compiler outside of a VS shell (e.g. in a MSYS shell or in a vanilla cmd.exe shell). This also makes cross compiles via Cargo "just work" when crossing between 32 and 64 bit!
* TLS destructors were fixed to start running on MSVC (they previously weren't running at all)
* A few assorted `run-pass` tests were fixed.
* The dependency on the `rust_builtin` library was removed entirely for MSVC to try to prevent any `cl.exe` compiled objects get into the standard library. This should help us later remove any dependence on the CRT by the standard library.
* I re-added `rust_try_msvc_32.ll` for 32-bit MSVC and ensured that landing pads were turned off by default there as well.
Despite landing pads being enabled, there are still *many* failing tests on MSVC. The two major classes I've identified so far are:
* Spurious aborts. It appears that when optimizations are enabled that landing pads aren't always lined up properly, and sometimes an exception being thrown can't find the catch block down the stack, causing the program to abort. I've been working to reduce this test case but haven't been met with great success just yet.
* Parallel codegen does not work on MSVC. Our current strategy is to take the N object files emitted by the N codegen threads and use `ld -r` to assemble them into *one* object file. The MSVC linker, however, does not have this ability, and this will need to be rearchitected to work on MSVC.
I will fix parallel codegen in a future PR, and I'll also be watching LLVM closely to see if the aborts... disappear!
