Use arena allocation instead of reference counting for `Module`s to fix memory leaks from `Rc` cycles.
A module references its module children and its import resolutions, and an import resolution references the module defining the imported name, so there is a cycle whenever a module imports something from an ancestor module.
For example,
```rust
mod foo { // `foo` references `bar`.
fn baz() {}
mod bar { // `bar` references the import.
use foo::baz; // The import references `foo`.
}
}
```
Rollup merge of #30851 - jonas-schievink:unneeded-dropflags, r=pnkfelix
Apparently we allocate and maintain non-working dropflag hints since June... In anticipation of a working implementation of on-stack drop flag hints, let's not spend even more time on types that don't even need to be dropped.
Rollup merge of #30850 - ranma42:cleanup-io, r=alexcrichton
In 8d90d3f36871a00023cc1f313f91e351c287ca15 `BufStream`, the only
consumer of `InternalBufWriter`, was removed. As implied by the name,
this type is private, hence it is currently dead code.
Rollup merge of #30839 - tomaka:debug-phantomdata, r=nikomatsakis
All the trait implementations of `PhantomData` use `impl<T: ?Sized>` except for `Debug`
https://doc.rust-lang.org/nightly/std/marker/struct.PhantomData.html#implementations
Rollup merge of #30837 - semarie:openbsd-libc, r=alexcrichton
The following PR updates libc version to latest commits for correctly support openbsd.
It corrects several points in rustc to be compatible with libc changes.
Rollup merge of #30823 - pnkfelix:put-back-alloca-zeroing-for-issue-30530, r=dotdash
Put back alloca zeroing for issues #29092, #30018, #30530; inject zeroing for #30822.
----
Background context: `fn alloca_zeroed` was removed in PR #22969, so we haven't been "zero'ing" (\*) the alloca's since at least that point, but the logic behind that PR seems sound, so its not entirely obvious how *long* the underlying bug has actually been present. In other words, I have not yet done a survey to see when the new `alloc_ty` and `lvalue_scratch_datum` calls were introduced that should have had "zero'ing" the alloca's.
----
I first fixed #30018, then decided to do a survey of `alloc_ty` calls to see if they needed similar treatment, which quickly led to a rediscovery of #30530.
While making the regression test for the latter, I discovered #30822, which is a slightly different bug (in terms of where the "zero'ing" needs to go), but still relevant.
I haven't finished the aforementioned survey of `fn alloc_ty` calls, but I decided I wanted to get this up for review in its current state (namely to see if my attempt to force developers to include a justification for passing `Uninit` can possibly fly, or if I should abandon that path of action).
----
(*): I am putting quotation marks around "zero'ing" because we no longer use zero as our "dropped" marker value.
Rollup merge of #30801 - Amanieu:oom_print, r=alexcrichton
This adds the ability to override the default OOM behavior by setting a handler function. This is used by libstd to print a message when running out of memory instead of crashing with an obscure "illegal hardware instruction" error (at least on Linux).
bors [Thu, 14 Jan 2016 01:26:54 +0000 (01:26 +0000)]
Auto merge of #30466 - alexcrichton:move-wrapping-and-fill-out, r=aturon
This commit migrates all of the methods on `num::wrapping::OverflowingOps` onto
inherent methods of the integer types. This also fills out some missing gaps in
the saturating and checked departments such as:
bors [Wed, 13 Jan 2016 22:27:46 +0000 (22:27 +0000)]
Auto merge of #30870 - Eljay:issue-30477, r=alexcrichton
Fixes #30477, #30213.
The loop over reexports used to be a closure before #30043 but it's an iterator now so it should just continue instead of exiting the loop and skipping stuff.
(Note that it might be a good idea to replace *all* calls of
`alloc_ty` with calls to `alloc_ty_init`, to encourage programmers to
consider the appropriate value for the `init` flag when creating
temporary values.)
* Only `call_lifetime_start` for an alloca if the function entry does
not itself initialize it to "dropped."
* Remove `schedule_lifetime_end` after writing an *element* into a
borrowed slice. (As explained by [dotdash][irc], "the lifetime end
that is being removed was for an element in the slice, which is not
an alloca of its own and has no lifetime start of its own")
bors [Wed, 13 Jan 2016 08:15:45 +0000 (08:15 +0000)]
Auto merge of #29498 - wthrowe:replace-pattern, r=alexcrichton
It appears this was left out of RFC rust-lang/rfcs#528 because it might be useful to
also generalize the second argument in some way. That doesn't seem to
prevent generalizing the first argument now, however.
This is a [breaking-change] because it could cause type-inference to
fail where it previously succeeded.
Also update docs for a few other methods that still referred to `&str` instead of patterns.
bors [Wed, 13 Jan 2016 02:05:02 +0000 (02:05 +0000)]
Auto merge of #30639 - rkruppe:dec2flt-fastpath-tables, r=alexcrichton
Add tables of small powers of ten used in the fast path. The tables are redundant: We could also use the big, more accurate table and round the value to the correct type (in fact we did just that before this commit). However, the rounding is extra work and slows down the fast path.
Because only very small exponents enter the fast path, the table and thus the space overhead is negligible. Speed-wise, this is a clear win on a [benchmark] comparing the fast path to a naive, hand-optimized, inaccurate algorithm. Specifically, this change narrows the gap from a roughly 5x difference to a roughly 3.4x difference.
Robin Kruppe [Wed, 30 Dec 2015 13:01:42 +0000 (14:01 +0100)]
Speed up dec2flt fast path with additional tables.
Add tables of small powers of ten used in the fast path. The tables are redundant: We could also use the big, more accurate table and round the value to the correct type (in fact we did just that before this commit). However, the rounding is extra work and slows down the fast path.
Because only very small exponents enter the fast path, the table and thus the space overhead is negligible. Speed-wise, this is a clear win on a [benchmark] comparing the fast path to a naive, hand-optimized, inaccurate algorithm. Specifically, this change narrows the gap from a roughly 5x difference to a roughly 3.4x difference.
Andrea Canciani [Tue, 12 Jan 2016 10:58:52 +0000 (11:58 +0100)]
Remove dead `InternalBufWriter` implementation
In 8d90d3f36871a00023cc1f313f91e351c287ca15 `BufStream`, the only
consumer of `InternalBufWriter`, was removed. As implied by the name,
this type is private, hence it is currently dead code.
Issue 30530: initialize allocas for `Datum::to_lvalue_datum_in_scope`.
In particular, bring back the `zero` flag for `lvalue_scratch_datum`,
which controls whether the alloca's created immediately at function
start are uninitialized at that point or have their embedded
drop-flags initialized to "dropped".
Then made `to_lvalue_datum_in_scope` pass "dropped" as `zero` flag.
bors [Tue, 12 Jan 2016 08:30:56 +0000 (08:30 +0000)]
Auto merge of #30678 - Amanieu:no_elf_tls, r=alexcrichton
I also re-enabled the use of `#[thread_local]` on AArch64. It was originally disabled in the PR that introduced AArch64 (#19790), but the reasons for this were not explained. `#[thread_local]` seems to work fine in my tests on AArch64, so I don't think this should be an issue.
Alex Crichton [Fri, 18 Dec 2015 18:24:06 +0000 (10:24 -0800)]
std: Move overflowing ops to inherent methods
This commit migrates all of the methods on `num::wrapping::OverflowingOps` onto
inherent methods of the integer types. This also fills out some missing gaps in
the saturating and checked departments such as:
bors [Tue, 12 Jan 2016 05:20:23 +0000 (05:20 +0000)]
Auto merge of #30635 - nagisa:mir-rid-unit-temp, r=nikomatsakis
Get rid of that nasty unit_ty temporary variable created just because it might be handy to have one around, when in reality it isn’t really that useful at all.
bors [Tue, 12 Jan 2016 03:00:00 +0000 (03:00 +0000)]
Auto merge of #30599 - brson:extra, r=alexcrichton
This mixes in additional information into the hash that is
passed to -C extra-filename. It can be used to further distinguish
the standard libraries if they must be installed next to each
other.
Closes #29559
Frankly, I'm not sure if this solves a real problem. It's meant to help with side-by-side and overlapping installations where there are two sets of libs in /usr, but there are other potential issues there as well, including that some of our artifacts don't use this extra-filename munging, and it's not something our installers can support at all.
cc @jauhien Do you still think this helps the Gentoo case?
Rollup merge of #30761 - nagisa:mir-fix-destination, r=michaelwoerister
Previously it was returning a clone, mostly for the two reasons:
* Cloning Lvalue is very cheap most of the time (i.e. when Lvalue is not a Projection);
* There’s users who want &mut lvalue and there’s users who want &lvalue. Returning a value allows
to make either one easier when pattern matching (i.e. Some(ref dest) or Some(ref mut dest)).
However, I’m now convinced this is an invalid approach. Namely the users which want a mutable
reference may modify the Lvalue in-place, but the changes won’t be reflected in the final MIR,
since the Lvalue modified is merely a clone.
Instead, we have two accessors `destination` and `destination_mut` which return a reference to the
destination in desired mode.
These should probably be submitted upstream. They're inevitably going to
complicate merges, and because they're non-functional changes this just
isn't worth our time.
bors [Mon, 11 Jan 2016 19:03:18 +0000 (19:03 +0000)]
Auto merge of #30534 - bluss:binary-heap-fast-pop, r=Gankro
BinaryHeap: Use full sift down in .pop()
.sift_down can either choose to compare the element on the way down (and
place it during descent), or to sift down an element fully, then sift
back up to place it.
A previous PR changed .sift_down() to the former behavior, which is much
faster for relatively small heaps and for elements that are cheap to
compare.
A benchmarking run suggested that BinaryHeap::pop() suffers
improportionally from this, and that it should use the second strategy
instead. It's logical since .pop() brings last element from the
heapified vector into index 0, it's very likely that this element will
end up at the bottom again.
bors [Mon, 11 Jan 2016 15:26:57 +0000 (15:26 +0000)]
Auto merge of #30676 - nikomatsakis:issue-29857, r=arielb1
This is an alternative to https://github.com/rust-lang/rust/pull/29954 for fixing #29857 that seems to me to be more inline with the general strategy around `TyError`. It also includes the fix for #30589 -- in fact, just the minimal change of making `ty_is_local` tolerate `TyError` avoids the ICE, but you get a lot of duplicate error reports, so in the case where the impl's trait reference already includes `TyError`, we just ignore the impl altogether.
bors [Mon, 11 Jan 2016 10:19:44 +0000 (10:19 +0000)]
Auto merge of #30490 - ipetkov:unix-spawn, r=alexcrichton
* If the requested descriptors to inherit are stdio descriptors there
are situations where they will not be set correctly
* Example: parent's stdout --> child's stderr
parent's stderr --> child's stdout
* Solution: if the requested descriptors for the child are stdio
descriptors, `dup` them before overwriting the child's stdio
Example of a program which exhibits the bug:
```rust
// stdio.rs
use std::io::Write;
use std::io::{stdout, stderr};
use std::process::{Command, Stdio};
use std::os::unix::io::FromRawFd;
bors [Mon, 11 Jan 2016 08:32:46 +0000 (08:32 +0000)]
Auto merge of #27807 - pczarn:arena-internals, r=bluss
Fixes #18037 "TypedArena cannot handle zero-sized types".
Closes #17931 "improve chunk allocation scheme used by Arena / TypedArena".
Closes #22847 "TypedArena should implement Send". - N.B. Arena cannot implement Send, since it may contain non-Send values.
Closes #18471 "`Arena::alloc_copy_inner` (at least) should be renamed and made public." - Added `Arena::alloc_bytes`.
Closes #18261 "support clearing TypedArena with the chunks preserved". - Only the largest chunk is preserved.
bors [Mon, 11 Jan 2016 06:40:58 +0000 (06:40 +0000)]
Auto merge of #30295 - jseyfried:fix_extern_crate_duplicate, r=nrc
Fix a bug allowing an item and an external crate to collide so long as the external crate is declared after the item. For example,
```rust
mod core { pub fn f() {} } // This would be an error if it followed the `extern crate`
extern crate core; // This declaration is shadowed by the preceding module
fn main() { core::f(); }
```
This is a [breaking-change], but it looks unlikely to cause breakage in practice, and any breakage can be fixed by removing colliding `extern crate` declarations, which are shadowed and hence unused.