bors [Sat, 7 Jun 2014 07:51:36 +0000 (00:51 -0700)]
auto merge of #14708 : gereeter/rust/faster-sem, r=alexcrichton
Currently, `Sem`, which is used as a building block for all the blocking primitives, uses a very ugly hack to implement `Share` and be able to mutate the stored `WaitQueue` by hiding it all behind a `transmute`d `*()`. This PR replaces all that ugly machinery with `Unsafe`. Beyond being cleaner and not requiring `transmute`, this removes an allocation in the creation and removes an indirection for access.
bors [Sat, 7 Jun 2014 06:06:35 +0000 (23:06 -0700)]
auto merge of #14638 : alexcrichton/rust/librustrt, r=brson
As part of the libstd facade efforts, this commit extracts the runtime interface
out of the standard library into a standalone crate, librustrt. This crate will
provide the following services:
* Definition of the rtio interface
* Definition of the Runtime interface
* Implementation of the Task structure
* Implementation of task-local-data
* Implementation of task failure via unwinding via libunwind
* Implementation of runtime initialization and shutdown
* Implementation of thread-local-storage for the local rust Task
Notably, this crate avoids the following services:
* Thread creation and destruction. The crate does not require the knowledge of
an OS threading system, and as a result it seemed best to leave out the
`rt::thread` module from librustrt. The librustrt module does depend on
mutexes, however.
* Implementation of backtraces. There is no inherent requirement for the runtime
to be able to generate backtraces. As will be discussed later, this
functionality continues to live in libstd rather than librustrt.
As usual, a number of architectural changes were required to make this crate
possible. Users of "stable" functionality will not be impacted by this change,
but users of the `std::rt` module will likely note the changes. A list of
architectural changes made is:
* The stdout/stderr handles no longer live directly inside of the `Task`
structure. This is a consequence of librustrt not knowing about `std::io`.
These two handles are now stored inside of task-local-data.
The handles were originally stored inside of the `Task` for perf reasons, and
TLD is not currently as fast as it could be. For comparison, 100k prints goes
from 59ms to 68ms (a 15% slowdown). This appeared to me to be an acceptable
perf loss for the successful extraction of a librustrt crate.
* The `rtio` module was forced to duplicate more functionality of `std::io`. As
the module no longer depends on `std::io`, `rtio` now defines structures such
as socket addresses, addrinfo fiddly bits, etc. The primary change made was
that `rtio` now defines its own `IoError` type. This type is distinct from
`std::io::IoError` in that it does not have an enum for what error occurred,
but rather a platform-specific error code.
The native and green libraries will be updated in later commits for this
change, and the bulk of this effort was put behind updating the two libraries
for this change (with `rtio`).
* Printing a message on task failure (along with the backtrace) continues to
live in libstd, not in librustrt. This is a consequence of the above decision
to move the stdout/stderr handles to TLD rather than inside the `Task` itself.
The unwinding API now supports registration of global callback functions which
will be invoked when a task fails, allowing for libstd to register a function
to print a message and a backtrace.
The API for registering a callback is experimental and unsafe, as the
ramifications of running code on unwinding is pretty hairy.
* The `std::unstable::mutex` module has moved to `std::rt::mutex`.
* The `std::unstable::sync` module has been moved to `std::rt::exclusive` and
the type has been rewritten to not internally have an Arc and to have an RAII
guard structure when locking. Old code should stop using `Exclusive` in favor
of the primitives in `libsync`, but if necessary, old code should port to
`Arc<Exclusive<T>>`.
* The local heap has been stripped down to have fewer debugging options. None of
these were tested, and none of these have been used in a very long time.
Alex Crichton [Wed, 4 Jun 2014 02:11:49 +0000 (19:11 -0700)]
std: Extract librustrt out of libstd
As part of the libstd facade efforts, this commit extracts the runtime interface
out of the standard library into a standalone crate, librustrt. This crate will
provide the following services:
* Definition of the rtio interface
* Definition of the Runtime interface
* Implementation of the Task structure
* Implementation of task-local-data
* Implementation of task failure via unwinding via libunwind
* Implementation of runtime initialization and shutdown
* Implementation of thread-local-storage for the local rust Task
Notably, this crate avoids the following services:
* Thread creation and destruction. The crate does not require the knowledge of
an OS threading system, and as a result it seemed best to leave out the
`rt::thread` module from librustrt. The librustrt module does depend on
mutexes, however.
* Implementation of backtraces. There is no inherent requirement for the runtime
to be able to generate backtraces. As will be discussed later, this
functionality continues to live in libstd rather than librustrt.
As usual, a number of architectural changes were required to make this crate
possible. Users of "stable" functionality will not be impacted by this change,
but users of the `std::rt` module will likely note the changes. A list of
architectural changes made is:
* The stdout/stderr handles no longer live directly inside of the `Task`
structure. This is a consequence of librustrt not knowing about `std::io`.
These two handles are now stored inside of task-local-data.
The handles were originally stored inside of the `Task` for perf reasons, and
TLD is not currently as fast as it could be. For comparison, 100k prints goes
from 59ms to 68ms (a 15% slowdown). This appeared to me to be an acceptable
perf loss for the successful extraction of a librustrt crate.
* The `rtio` module was forced to duplicate more functionality of `std::io`. As
the module no longer depends on `std::io`, `rtio` now defines structures such
as socket addresses, addrinfo fiddly bits, etc. The primary change made was
that `rtio` now defines its own `IoError` type. This type is distinct from
`std::io::IoError` in that it does not have an enum for what error occurred,
but rather a platform-specific error code.
The native and green libraries will be updated in later commits for this
change, and the bulk of this effort was put behind updating the two libraries
for this change (with `rtio`).
* Printing a message on task failure (along with the backtrace) continues to
live in libstd, not in librustrt. This is a consequence of the above decision
to move the stdout/stderr handles to TLD rather than inside the `Task` itself.
The unwinding API now supports registration of global callback functions which
will be invoked when a task fails, allowing for libstd to register a function
to print a message and a backtrace.
The API for registering a callback is experimental and unsafe, as the
ramifications of running code on unwinding is pretty hairy.
* The `std::unstable::mutex` module has moved to `std::rt::mutex`.
* The `std::unstable::sync` module has been moved to `std::rt::exclusive` and
the type has been rewritten to not internally have an Arc and to have an RAII
guard structure when locking. Old code should stop using `Exclusive` in favor
of the primitives in `libsync`, but if necessary, old code should port to
`Arc<Exclusive<T>>`.
* The local heap has been stripped down to have fewer debugging options. None of
these were tested, and none of these have been used in a very long time.
Alex Crichton [Fri, 6 Jun 2014 16:12:18 +0000 (09:12 -0700)]
rustdoc: Submit examples to play.rust-lang.org
This grows a new option inside of rustdoc to add the ability to submit examples
to an external website. If the `--markdown-playground-url` command line option
or crate doc attribute `html_playground_url` is present, then examples will have
a button on hover to submit the code to the playground specified.
This commit enables submission of example code to play.rust-lang.org. The code
submitted is that which is tested by rustdoc, not necessarily the exact code
shown in the example.
Alex Crichton [Sat, 7 Jun 2014 00:48:46 +0000 (17:48 -0700)]
rustc: Preserve reachable extern fns with LTO
All rust functions are internal implementation details with respect to the ABI
exposed by crates, but extern fns are public components of the ABI and shouldn't
be stripped. This commit serializes reachable extern fns to metadata, so when
LTO is performed all of their symbols are not stripped.
Aaron Turon [Fri, 6 Jun 2014 06:18:51 +0000 (23:18 -0700)]
Rename Iterator::len to count
This commit carries out the request from issue #14678:
> The method `Iterator::len()` is surprising, as all the other uses of
> `len()` do not consume the value. `len()` would make more sense to be
> called `count()`, but that would collide with the current
> `Iterator::count(|T| -> bool) -> unit` method. That method, however, is
> a bit redundant, and can be easily replaced with
> `iter.filter(|x| x < 5).count()`.
> After this change, we could then define the `len()` method
> on `iter::ExactSize`.
Alex Crichton [Thu, 5 Jun 2014 22:31:45 +0000 (15:31 -0700)]
rustc: Avoid 16-byte filenames in rlibs
In addition to avoiding 16-byte filenames with bytecode files, this commit also
avoids 16-byte filenames with object files pulled in from native libraries.
LLDB contains a bug that makes it crash if an archive it reads
contains a file the name of which is exactly 16 bytes long. This
bug recently has made it impossible to debug Rust applications with
LLDB because some standard libraries triggered it indirectly:
For rlibs, rustc includes the LLVM bytecode in the archive, giving
it the extension ".bc.deflate". For liballoc (for example) this
results in the 16 character filename "alloc.bc.deflate", which is
bad.
This commit replaces the ".bc.deflate" suffix with
".bytecode.deflate" which itself is already longer than 16 bytes,
thus making sure that the bug won't be run into anymore.
The bug could still be run into with 14 character filenames because
then the .o files will trigger it. However, this is much more rare
and working around it would introduce more complexity than necessary
at the moment. It can always be done later on, if the need arises.
Alex Crichton [Thu, 5 Jun 2014 19:23:34 +0000 (12:23 -0700)]
rustc: Avoid UB with signed division/remainder
Division and remainder by 0 are undefined behavior, and are detected at runtime.
This commit adds support for ensuring that MIN / -1 is also checked for at
runtime, as this would cause signed overflow, or undefined behvaior.
bors [Fri, 6 Jun 2014 19:17:10 +0000 (12:17 -0700)]
auto merge of #14318 : zwarich/rust/check-loans-refactor, r=nikomatsakis
I tried to split up the less mechanical changes into separate commits so they are easier to review. One thing I'm not quite sure of is whether `MoveReason` should just be replaced with `move_data::MoveKind`.
Cameron Zwarich [Fri, 6 Jun 2014 18:59:33 +0000 (11:59 -0700)]
Add a test for borrowck errors with multiple closure captures.
When converting check_loans to use ExprUseVisitor I encountered a few
issues where the wrong number of errors were being emitted for multiple
closure captures, but there is no existing test for this.
Cameron Zwarich [Fri, 6 Jun 2014 18:59:33 +0000 (11:59 -0700)]
Add a move reason to the Move ConsumeMode.
Currently it is not possible to distinguish moves caused by captures
in the ExprUseVisitor interface. Since check_Loans needs to make that
distinction for generating good diagnostics, this is necessary for
check_loans to switch to ExprUseVisitor.
Cameron Zwarich [Fri, 6 Jun 2014 18:59:32 +0000 (11:59 -0700)]
Add an Init mode to MutateMode.
This isn't necessary right now, but check_loans needs to be able to
distinguish between initialization and writes in the ExprUseVisitor
mutate callback.
Cameron Zwarich [Fri, 6 Jun 2014 18:59:32 +0000 (11:59 -0700)]
Fix mem_categorization to treat an AutoObject adjustment as an rvalue.
Currently mem_categorization categorizes an AutoObject adjustment the
same as the original expression. This can cause two moves to be
generated for the same underlying expression. Currently this isn't a
problem in practice, since check_loans doesn't rely on ExprUseVisitor.
Cameron Zwarich [Fri, 6 Jun 2014 18:59:32 +0000 (11:59 -0700)]
Clean up check_loans.
Refactor a number of functions in check_loans to take node IDs and spans
rather than taking expressions directly. Also rename some variables to
make them less ambiguous.
This is the first step towards using ExprUseVisitor in check_loans, as
now some of the interfaces more closely match those used in
ExprUseVisitor.
bors [Fri, 6 Jun 2014 01:36:56 +0000 (18:36 -0700)]
auto merge of #14653 : alexcrichton/rust/travis-opt, r=cmr
The most frequent failure for our travis builds is running into the timeout
limits when building the compiler itself. Building librustc takes a very long
amount of time, often hitting the 10 minutes with no output threshold that
travis imposes on us.
This commit switches the relevant `make` step to being wrapped in the
`travis_wait` command [1]. This command will print something once a minute so as
to not time out a build.
This will hopefully enable us to have fewer flaky builds on travis!
bors [Thu, 5 Jun 2014 22:01:54 +0000 (15:01 -0700)]
auto merge of #14538 : alexcrichton/rust/libcollections, r=brson
As with the previous commit with `librand`, this commit shuffles around some
`collections` code. The new state of the world is similar to that of librand:
* The libcollections crate now only depends on libcore and liballoc.
* The standard library has a new module, `std::collections`. All functionality
of libcollections is reexported through this module.
I would like to stress that this change is purely cosmetic. There are very few
alterations to these primitives.
There are a number of notable points about the new organization:
* std::{str, slice, string, vec} all moved to libcollections. There is no reason
that these primitives shouldn't be necessarily usable in a freestanding
context that has allocation. These are all reexported in their usual places in
the standard library.
* The `hashmap`, and transitively the `lru_cache`, modules no longer reside in
`libcollections`, but rather in libstd. The reason for this is because the
`HashMap::new` contructor requires access to the OSRng for initially seeding
the hash map. Beyond this requirement, there is no reason that the hashmap
could not move to libcollections.
I do, however, have a plan to move the hash map to the collections module. The
`HashMap::new` function could be altered to require that the `H` hasher
parameter ascribe to the `Default` trait, allowing the entire `hashmap` module
to live in libcollections. The key idea would be that the default hasher would
be different in libstd. Something along the lines of:
// src/libstd/collections/mod.rs
pub type HashMap<K, V, H = RandomizedSipHasher> =
core_collections::HashMap<K, V, H>;
This is not possible today because you cannot invoke static methods through
type aliases. If we modified the compiler, however, to allow invocation of
static methods through type aliases, then this type definition would
essentially be switching the default hasher from `SipHasher` in libcollections
to a libstd-defined `RandomizedSipHasher` type. This type's `Default`
implementation would randomly seed the `SipHasher` instance, and otherwise
perform the same as `SipHasher`.
This future state doesn't seem incredibly far off, but until that time comes,
the hashmap module will live in libstd to not compromise on functionality.
* In preparation for the hashmap moving to libcollections, the `hash` module has
moved from libstd to libcollections. A previously snapshotted commit enables a
distinct `Writer` trait to live in the `hash` module which `Hash`
implementations are now parameterized over.
Due to using a custom trait, the `SipHasher` implementation has lost its
specialized methods for writing integers. These can be re-added
backwards-compatibly in the future via default methods if necessary, but the
FNV hashing should satisfy much of the need for speedier hashing.
A list of breaking changes:
* HashMap::{get, get_mut} no longer fails with the key formatted into the error
message with `{:?}`, instead, a generic message is printed. With backtraces,
it should still be not-too-hard to track down errors.
* The HashMap, HashSet, and LruCache types are now available through
std::collections instead of the collections crate.
* Manual implementations of hash should be parameterized over `hash::Writer`
instead of just `Writer`.
Alex Crichton [Fri, 30 May 2014 01:50:12 +0000 (18:50 -0700)]
std: Recreate a `collections` module
As with the previous commit with `librand`, this commit shuffles around some
`collections` code. The new state of the world is similar to that of librand:
* The libcollections crate now only depends on libcore and liballoc.
* The standard library has a new module, `std::collections`. All functionality
of libcollections is reexported through this module.
I would like to stress that this change is purely cosmetic. There are very few
alterations to these primitives.
There are a number of notable points about the new organization:
* std::{str, slice, string, vec} all moved to libcollections. There is no reason
that these primitives shouldn't be necessarily usable in a freestanding
context that has allocation. These are all reexported in their usual places in
the standard library.
* The `hashmap`, and transitively the `lru_cache`, modules no longer reside in
`libcollections`, but rather in libstd. The reason for this is because the
`HashMap::new` contructor requires access to the OSRng for initially seeding
the hash map. Beyond this requirement, there is no reason that the hashmap
could not move to libcollections.
I do, however, have a plan to move the hash map to the collections module. The
`HashMap::new` function could be altered to require that the `H` hasher
parameter ascribe to the `Default` trait, allowing the entire `hashmap` module
to live in libcollections. The key idea would be that the default hasher would
be different in libstd. Something along the lines of:
// src/libstd/collections/mod.rs
pub type HashMap<K, V, H = RandomizedSipHasher> =
core_collections::HashMap<K, V, H>;
This is not possible today because you cannot invoke static methods through
type aliases. If we modified the compiler, however, to allow invocation of
static methods through type aliases, then this type definition would
essentially be switching the default hasher from `SipHasher` in libcollections
to a libstd-defined `RandomizedSipHasher` type. This type's `Default`
implementation would randomly seed the `SipHasher` instance, and otherwise
perform the same as `SipHasher`.
This future state doesn't seem incredibly far off, but until that time comes,
the hashmap module will live in libstd to not compromise on functionality.
* In preparation for the hashmap moving to libcollections, the `hash` module has
moved from libstd to libcollections. A previously snapshotted commit enables a
distinct `Writer` trait to live in the `hash` module which `Hash`
implementations are now parameterized over.
Due to using a custom trait, the `SipHasher` implementation has lost its
specialized methods for writing integers. These can be re-added
backwards-compatibly in the future via default methods if necessary, but the
FNV hashing should satisfy much of the need for speedier hashing.
A list of breaking changes:
* HashMap::{get, get_mut} no longer fails with the key formatted into the error
message with `{:?}`, instead, a generic message is printed. With backtraces,
it should still be not-too-hard to track down errors.
* The HashMap, HashSet, and LruCache types are now available through
std::collections instead of the collections crate.
* Manual implementations of hash should be parameterized over `hash::Writer`
instead of just `Writer`.
bors [Thu, 5 Jun 2014 20:26:53 +0000 (13:26 -0700)]
auto merge of #14647 : BurntSushi/rust/fix-14185, r=alexcrichton
This fix suppresses dead_code warnings from code generated by regex! when
the result of regex! is unused. Correct behavior should be a single
unused variable warning.
Regression tests are included for both `let` and `static` bound regex!
values.
bors [Thu, 5 Jun 2014 18:06:53 +0000 (11:06 -0700)]
auto merge of #14526 : pczarn/rust/hashmap-opt, r=alexcrichton
An interface that gives a better control over the load factor and the minimum capacity for HashMap.
The size of `HashMap<K, V>` is now 64 bytes by default on a 64-bit platform (or at least 40 bytes, that is 3 words less, with FNV and without minimum capacity)
Unanswered questions about `ResizePolicy`
* should it control the `INITIAL_CAPACITY`?
* should it fully control the resizing behavior? Even though the capacity always changes by a factor of 2.
* is caching `grow_at` desirable?
bors [Thu, 5 Jun 2014 15:26:51 +0000 (08:26 -0700)]
auto merge of #14644 : alexcrichton/rust/more-no-runtime-use-cases, r=brson
A few notable improvements were implemented to cut down on the number of aborts
triggered by the standard library when a local task is not found.
* Primarily, the unwinding functionality was restructured to support an unsafe
top-level function, `try`. This function invokes a closure, capturing any
failure which occurs inside of it. The purpose of this function is to be as
lightweight of a "try block" as possible for rust, intended for use when the
runtime is difficult to set up.
This function is *not* meant to be used by normal rust code, nor should it be
consider for use with normal rust code.
* When invoking spawn(), a `fail!()` is triggered rather than an abort.
* When invoking LocalIo::borrow(), which is transitively called by all I/O
constructors, None is returned rather than aborting to indicate that there is
no local I/O implementation.
A test case was also added showing the variety of things that you can do without
a runtime or task set up now. In general, this is just a refactoring to abort
less quickly in the standard library when a local task is not found.
bors [Thu, 5 Jun 2014 07:51:48 +0000 (00:51 -0700)]
auto merge of #14568 : erickt/rust/slice-update, r=alexcrichton
This PR adds two features to make it possible to transform an `Iterator<u8>` into a `Reader`. The first patch adds a method to mutable slices that allows it to be updated with an `Iterator<T>` without paying for the bounds cost. The second adds a Iterator adaptor, `IterReader`, to provide that `Reader` interface.
I had two questions. First, are these named the right things? Second, should `IterReader` instead wrap an `Iterator<Result<u8, E>>`? This would allow you to `IterReader::new(rdr.bytes())`, which could be useful if you want to apply some iterator transformations on a reader while still exporting the Reader interface, but I'd expect there'd be a lot of overhead annotating each byte with an error result.
bors [Thu, 5 Jun 2014 03:41:44 +0000 (20:41 -0700)]
auto merge of #14610 : alexcrichton/rust/issue-14008, r=brson
This commit removes the <M: Any + Send> type parameter from Option::expect in
favor of just taking a hard-coded `&str` argument. This allows this function to
move into libcore.
Previous code using strings with `expect` will continue to work, but code using
this implicitly to transmit task failure will need to unwrap manually with a
`match` statement.
bors [Thu, 5 Jun 2014 01:56:48 +0000 (18:56 -0700)]
auto merge of #14529 : brson/rust/ptr, r=brson
This time we're not promoting anything directly to 'stable', but instead promoting functions we're happy with to 'unstable'. They'll become stable in another pass later.
* null and mut_null are unstable. Their names may change if the unsafe
pointer types change.
* copy_memory and copy_overlapping_memory are unstable. We think they
aren't going to change.
* set_memory and zero_memory are experimental. Both the names and
the semantics are under question.
* swap and replace are unstable and probably won't change.
* read is unstable, probably won't change
* read_and_zero is experimental. It's necessity is in doubt.
* mem::overwrite is now called ptr::write to match read and is
unstable. mem::overwrite is now deprecated
* array_each, array_each_with_len, buf_len, and position are
all deprecated because they use old style iteration and their
utility is generally under question.
Note that `mem::overwrite`, which was just declared stable last week, is deprecated now in favor of `ptr::write`. Woo!
Brian Anderson [Fri, 30 May 2014 00:40:18 +0000 (17:40 -0700)]
core: Apply stability attributes to ptr mod
* null and mut_null are unstable. Their names may change if the unsafe
pointer types change.
* copy_memory and copy_overlapping_memory are unstable. We think they
aren't going to change.
* set_memory and zero_memory are experimental. Both the names and
the semantics are under question.
* swap and replace are unstable and probably won't change.
* read is unstable, probably won't change
* read_and_zero is experimental. It's necessity is in doubt.
* mem::overwrite is now called ptr::write to match read and is
unstable. mem::overwrite is now deprecated
* array_each, array_each_with_len, buf_len, and position are
all deprecated because they use old style iteration and their
utility is generally under question.
Alex Crichton [Wed, 4 Jun 2014 19:00:42 +0000 (12:00 -0700)]
travis: Prevent timeouts with travis_wait
The most frequent failure for our travis builds is running into the timeout
limits when building the compiler itself. Building librustc takes a very long
amount of time, often hitting the 10 minutes with no output threshold that
travis imposes on us.
This commit switches the relevant `make` step to being wrapped in the
`travis_wait` command [1]. This command will print something once a minute so as
to not time out a build.
This will hopefully enable us to have fewer flaky builds on travis!
Andrew Gallant [Wed, 4 Jun 2014 20:59:27 +0000 (16:59 -0400)]
Fixes #14185.
This fix suppresses dead_code warnings from code generated by regex! when
the result of regex! is unused. Correct behavior should be a single
unused variable warning.
Regression tests are included for both `let` and `static` bound regex!
values.
bors [Wed, 4 Jun 2014 20:06:47 +0000 (13:06 -0700)]
auto merge of #14630 : cmr/rust/rewrite-lexer, r=alexcrichton
These are a pain to rebase, so I'm separating this from the rest of my work.
Nothing controversial here, just some simple refactoring and removal of an
unused entry in the token table. Brings the lexer into 2012 with methods!
Alex Crichton [Wed, 4 Jun 2014 17:54:35 +0000 (10:54 -0700)]
std: Improve non-task-based usage
A few notable improvements were implemented to cut down on the number of aborts
triggered by the standard library when a local task is not found.
* Primarily, the unwinding functionality was restructured to support an unsafe
top-level function, `try`. This function invokes a closure, capturing any
failure which occurs inside of it. The purpose of this function is to be as
lightweight of a "try block" as possible for rust, intended for use when the
runtime is difficult to set up.
This function is *not* meant to be used by normal rust code, nor should it be
consider for use with normal rust code.
* When invoking spawn(), a `fail!()` is triggered rather than an abort.
* When invoking LocalIo::borrow(), which is transitively called by all I/O
constructors, None is returned rather than aborting to indicate that there is
no local I/O implementation.
* Invoking get() on a TLD key will return None if no task is available
* Invoking replace() on a TLD key will fail if no task is available.
A test case was also added showing the variety of things that you can do without
a runtime or task set up now. In general, this is just a refactoring to abort
less quickly in the standard library when a local task is not found.
bors [Wed, 4 Jun 2014 18:06:49 +0000 (11:06 -0700)]
auto merge of #14623 : exscape/rust-fork/master, r=alexcrichton
Unlike ImmutableClonableVector::permutations() which returns an iterator,
cloning the entire array each iteration, these methods mutate the vector in-place.
For that reason, these methods are much faster; between 35-55 times faster,
depending on the benchmark. They also generate permutations in lexicographical order.
Refactored the load factor and the minimum capacity out of HashMap.
The size of HashMap<K, V> is now 64 bytes by default on a 64-bit platform
(or 48 bytes, that is 2 words less, with FNV)
Added a documentation in a few places to clarify the behavior.
bors [Wed, 4 Jun 2014 05:01:43 +0000 (22:01 -0700)]
auto merge of #14634 : BurntSushi/rust/fix-13843, r=alexcrichton
An empty regex is a valid regex that always matches. This behavior
is consistent with at least Go and Python.
A couple regression tests are included.
I'd just assume that an empty regex is an invalid regex and that an error should be returned (I can't think of any reason to use an empty regex?), but it's probably better to be consistent with other regex libraries.
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