Restore original meaning of std::fs::read_dir's example changed in #33958
`DirEntry.file_type().is_dir()` will not follow symlinks, but the original example (`fs::metadata(&path).is_dir()`) does. Therefore the change in #33958 introduced a subtle difference that now it won't enter linked folders. To preserve the same behavior, we use `Path::is_dir()` instead, which does follow symlink.
(See discussion in the previous PR for detail.)
Open code the __fastfail intrinsic for rtabort! on windows
As described https://msdn.microsoft.com/en-us/library/dn774154.aspx
This is a Windows 8+ mechanism for terminating the process quickly,
which degrades to either an access violation or bugcheck in older versions.
I'm not sure this is better the the current mechanism of terminating
with an illegal instruction, but we recently converted unix to
terminate more correctly with SIGABORT, and this *seems* more correct
for windows.
[breaking-change]
DirEntry.file_type().is_dir() will not follow symlinks, but the original
example (fs::metadata(&path).is_dir()) does. Therefore the change in
#33958 introduced a subtle difference that now it won't enter linked
folders. To preserve the same behavior, we use Path::is_dir() instead,
which does follow symlink.
Inline simple Cursor write calls
Implementing the Write trait for Cursors over slices is so light-weight that under some circumstances multiple writes can be fused into a single instruction. In general I think inlining these functions is a good idea because most of the code can be constant-folded and copy-propagated away.
Closes issue #33916.
r? @alexcrichton
Implement Error trait for fmt::Error type
Fixes#33827.
r? @alexcrichton
Just one last thing: I added a feature name, but don't hesitate to ask me to change it if you think it doesn't fit well.
panic.rs: fix docs (recover -> catch_unwind)
The current docs are a bit inconsistent. First, change all references of "recover" to "catch_unwind" because the function was renamed. Second, consistently use the term "unwind safe" instead of "panic safe", "exception safe" and "recover safe" (all these terms were used previously).
Implementing the Write trait for Cursors over slices is so light-weight that under some circumstances multiple writes can be fused into a single instruction. In general I think inlining these functions is a good idea because most of the code can be constant-folded and copy-propagated away.
Closes issue #33916.
As described https://msdn.microsoft.com/en-us/library/dn774154.aspx
This is a Windows 8+ mechanism for terminating the process quickly,
which degrades to either an access violation or bugcheck in older versions.
I'm not sure this is better the the current mechanism of terminating
with an illegal instruction, but we recently converted unix to
terminate more correctly with SIGABORT, and this *seems* more correct
for windows.
[breaking-change]
The current docs are a bit inconsistent. First, change all references of "recover" to "catch_unwind" because the function was renamed. Second, consistently use the term "unwind safe" instead of "panic safe", "exception safe" and "recover safe" (all these terms were used previously).
Deprecate {f32,f64}::abs_sub.
The abs_sub name is misleading: the function actually computes the
positive difference (`fdim` in C), not the `(x - y).abs()` that *many* people expect
from the name.
This function can be replaced with just `(x - y).max(0.0)`, mirroring
the `abs` version, but this behaves differently with NAN: `NAN.max(0.0)
== 0.0`, while `NAN.positive_diff(0.0) == NAN`. People who absolutely
need that behaviour can use the C function directly and/or talk to the libs
team (we haven't encountered a concrete use-case for this functionality).
Closes#30315.
Use libc::abort, not intrinsics::abort, in rtabort!
intrinsics::abort compiles down to an illegal instruction, which on
Unix-like platforms causes the process to be killed with SIGILL. A more
appropriate way to kill the process would be SIGABRT; this indicates
better that the runtime has explicitly aborted, rather than some kind of
compiler bug or architecture mismatch that SIGILL might indicate.
For rtassert!, replace this with libc::abort. libc::abort raises
SIGABRT, but is defined to do so in such a way that it will terminate
the process even if SIGABRT is currently masked or caught by a signal
handler that returns.
On non-Unix platforms, retain the existing behavior. On Windows we
prefer to avoid depending on the C runtime, and we need a fallback for
any other platforms that may be defined. An alternative on Windows
would be to call TerminateProcess, but this seems less essential than
switching to using SIGABRT on Unix-like platforms, where it is common
for the process-killing signal to be printed out or logged.
This is a [breaking-change] for any code that depends on the exact
signal raised to abort a process via rtabort!
cc #31273
cc #31333
intrinsics::abort compiles down to an illegal instruction, which on
Unix-like platforms causes the process to be killed with SIGILL. A more
appropriate way to kill the process would be SIGABRT; this indicates
better that the runtime has explicitly aborted, rather than some kind of
compiler bug or architecture mismatch that SIGILL might indicate.
For rtassert!, replace this with libc::abort. libc::abort raises
SIGABRT, but is defined to do so in such a way that it will terminate
the process even if SIGABRT is currently masked or caught by a signal
handler that returns.
On non-Unix platforms, retain the existing behavior. On Windows we
prefer to avoid depending on the C runtime, and we need a fallback for
any other platforms that may be defined. An alternative on Windows
would be to call TerminateProcess, but this seems less essential than
switching to using SIGABRT on Unix-like platforms, where it is common
for the process-killing signal to be printed out or logged.
This is a [breaking-change] for any code that depends on the exact
signal raised to abort a process via rtabort!
cc #31273
cc #31333
This is a rebase and extension of #31356 where we cache the keys in thread local
storage. This should give us a nice speed bost in creating hash maps along with
mostly retaining the property that all maps have a nondeterministic iteration
order.
Closes#27243
Added a big-picture explanation for thread::park() & co.
As I said in https://www.reddit.com/r/rust/comments/4ihvv1/hey_rust_programmers_got_a_question_ask_here/d372s4i, the current explanation of the `park()` and `unpark()` is a bit unclear. It says that they're used for blocking, but then it goes on explaining the semantics in detail, leaving the bigger picture a bit unclear.
I added a short high-level explanation that explains how the functions are used. I also exposed the full paths (`thread::park()` and `thread::Thread::unpark()`), because `unpark()`, being a method, is not directly visible at the module level.
The abs_sub name is misleading: the function actually computes the
positive difference (`fdim` in C), not the `(x - y).abs()` that *many* people expect
from the name.
This function can be replaced with just `(x - y).max(0.0)`, mirroring
the `abs` version, but this behaves differently with NAN: `NAN.max(0.0)
== 0.0`, while `NAN.positive_diff(0.0) == NAN`. People who absolutely
need that behaviour can use the C function directly and/or talk to the libs
team (we haven't encountered a concrete use-case for this functionality).
Closes#30315.
Don't use env::current_exe with libbacktrace
If the path we give to libbacktrace doesn't actually correspond to the
current process, libbacktrace will segfault *at best*.
cc #21889
r? @alexcrichton
cc @semarie
This commit adds support to rustbuild to run crate unit tests (those defined by
`#[test]`) as well as documentation tests. All tests are powered by `cargo test`
under the hood.
Each step requires the `libtest` library is built for that corresponding stage.
Ideally the `test` crate would be a dev-dependency, but for now it's just easier
to ensure that we sequence everything in the right order.
Currently no filtering is implemented, so there's not actually a method of
testing *only* libstd or *only* libcore, but rather entire swaths of crates are
tested all at once.
A few points of note here are:
* The `coretest` and `collectionstest` crates are just listed as `[[test]]`
entires for `cargo test` to naturally pick up. This mean that `cargo test -p
core` actually runs all the tests for libcore.
* Libraries that aren't tested all mention `test = false` in their `Cargo.toml`
* Crates aren't currently allowed to have dev-dependencies due to
rust-lang/cargo#860, but we can likely alleviate this restriction once
workspaces are implemented.
cc #31590
rustc: Implement custom panic runtimes
This commit is an implementation of [RFC 1513] which allows applications to
alter the behavior of panics at compile time. A new compiler flag, `-C panic`,
is added and accepts the values `unwind` or `panic`, with the default being
`unwind`. This model affects how code is generated for the local crate, skipping
generation of landing pads with `-C panic=abort`.
[RFC 1513]: https://github.com/rust-lang/rfcs/blob/master/text/1513-less-unwinding.md
Panic implementations are then provided by crates tagged with
`#![panic_runtime]` and lazily required by crates with
`#![needs_panic_runtime]`. The panic strategy (`-C panic` value) of the panic
runtime must match the final product, and if the panic strategy is not `abort`
then the entire DAG must have the same panic strategy.
With the `-C panic=abort` strategy, users can expect a stable method to disable
generation of landing pads, improving optimization in niche scenarios,
decreasing compile time, and decreasing output binary size. With the `-C
panic=unwind` strategy users can expect the existing ability to isolate failure
in Rust code from the outside world.
Organizationally, this commit dismantles the `sys_common::unwind` module in
favor of some bits moving part of it to `libpanic_unwind` and the rest into the
`panicking` module in libstd. The custom panic runtime support is pretty similar
to the custom allocator support with the only major difference being how the
panic runtime is injected (takes the `-C panic` flag into account).
Closes#32837
Currently the compiler has two relatively critical bugs in the implementation of
MSVC unwinding:
* #33112 - faults like segfaults and illegal instructions will run destructors
in Rust, meaning we keep running code after a super-fatal exception
has happened.
* #33116 - When compiling with LTO plus `-Z no-landing-pads` (or `-C
panic=abort` with the previous commit) LLVM won't remove all `invoke`
instructions, meaning that some landing pads stick around and
cleanups may be run due to the previous bug.
These both stem from the flavor of "personality function" that Rust uses for
unwinding on MSVC. On 32-bit this is `_except_handler3` and on 64-bit this is
`__C_specific_handler`, but they both essentially are the "most generic"
personality functions for catching exceptions and running cleanups. That is,
thse two personalities will run cleanups for all exceptions unconditionally, so
when we use them we run cleanups for **all SEH exceptions** (include things like
segfaults).
Note that this also explains why LLVM won't optimize away `invoke` instructions.
These functions can legitimately still unwind (the `nounwind` attribute only
seems to apply to "C++ exception-like unwining"). Also note that the standard
library only *catches* Rust exceptions, not others like segfaults and illegal
instructions.
LLVM has support for another personality, `__CxxFrameHandler3`, which does not
run cleanups for general exceptions, only C++ exceptions thrown by
`_CxxThrowException`. This essentially ideally matches our use case, so this
commit moves us over to using this well-known personality function as well as
exception-throwing function.
This doesn't *seem* to pull in any extra runtime dependencies just yet, but if
it does we can perhaps try to work out how to implement more of it in Rust
rather than relying on MSVCRT runtime bits.
More details about how this is actually implemented can be found in the changes
itself, but this...
Closes#33112Closes#33116
