spawn() is expected to return an error if the specified file could not be
executed.  FreeBSD's posix_spawn() supports returning ENOENT/ENOEXEC if
the exec() fails, which not all platforms support.  This brings a very
significant performance improvement for FreeBSD, involving heavy use of
Command in threads, due to fork() invoking jemalloc fork handlers and
causing lock contention.  FreeBSD's posix_spawn() avoids this problem
due to using vfork() internally.

…_version()

The relevant support was added in https://sourceware.org/bugzilla/show_bug.cgi?id=10354#c12

We apparently used to generate bad/incomplete debug info causing
debuggers not to find symbols of stack allocated variables. This was
somehow worked around by having frame pointers.

With the current codegen, this seems no longer necessary, so we can
remove the code that force-enables frame pointers whenever debug info
is requested.

Since certain situations, like profiling code profit from having frame
pointers, we add a -Cforce-frame-pointers flag to always enable frame
pointers.

Fixes rust-lang#11906

This reworks the force-frame-pointer PR to explicitly only consider the
value of the flag if it is provided, and use a target default otherwise.

Something that was tried but not kept was renaming the flag to
`frame-pointer`, because for flag `frame-pointer=no`, there is no
guarante, that LLVM will elide *all* the frame pointers; oposite of what
the literal reading of the flag would suggest.

Related to rust-lang#46753

Fixes rust-lang#46753

Fixes rust-lang#46753

Fixes rust-lang#46753

Related to rust-lang#48939

…for non-lexical lifetimes)

… for Default Type Parameter Fallback)

…for const generics)

…f AsRef for Deref)

…ation ergonomics)

…f Visitor

…besides host

…r measure

…terators

explicitly pass -L target-lib to rustdoc

…ang#47737"

This reverts commit 16ac85c.

The expected behavior is that the environment's PATH should be used
to find the process.  posix_spawn() could be used if we iterated
PATH to search for the binary to execute.  For now just skip
posix_spawn() if PATH is modified.

Fixes rust-lang#47326

This avoids the issues of the previous substring matching, ensuring
`ARCH_TABLE` and `OS_TABLE` will no longer contain redundant entries.

…e` is unavailable

This extends the Chalk lowering pass with the "Implemented-From-Env" rule for generating program clauses from a trait definition as part of rust-lang#49177.

…table statics

…s counter measure"

This reverts commit be73a1f.

This removes 10 dependencies from the build 🎉

…released."

This reverts commit 20e65f1.

…tart, r=QuietMisdreavus

Add warning for invalid start of code blocks in rustdoc

Follow up of rust-lang#48382.

Still two things to consider:
 1. Adding test for rustdoc output (but where? In UI or in rustdoc tests?).
 2. Try to fix the span issue.

r? @QuietMisdreavus

…xcrichton

Command: Support posix_spawn() on FreeBSD/OSX/GNU Linux

Add force-frame-pointer flag to allow control of frame pointer ommision

Rebase of rust-lang#47152 plus some changes suggested by rust-lang#48785.

Fixes rust-lang#11906

r? @nikomatsakis

… r=michaelwoerister

Querify WF-checking so it can be cached

r? @michaelwoerister

The trait and some of its methods are stable and will remain.
Some of the newer methods are unstable and can be removed later.

Fixes rust-lang#39658

…ister

Convert SerializedDepGraph to be a struct-of-arrays

Fixes rust-lang#47326

I did not try the "`mem::swap()` to avoid copying the arrays" idea because that would leave the DepGraph in an incorrect state and that doesn't seem like a good idea for me.

r? @michaelwoerister

Update submodules in parallel

address some FIXME whose associated issues were marked as closed

part of rust-lang#44366

…ichton

Allow test target to pass without installing

explicitly pass -L target-lib to rustdoc

on OpenBSD, without it, it fails on several tests with:
```
error[E0463]: can't find crate for `std`
```

Make compiletest do exact matching on triples

This avoids the issues of the previous substring matching, ensuring `ARCH_TABLE` and `OS_TABLE` will no longer contain redundant entries. Fixes rust-lang#48893.

r? @rkruppe

…uietMisdreavus

Put `#[macro_use] extern crate <crate>` before fn main() in doctests

Closes rust-lang#49174.

…-links, r=QuietMisdreavus

Fix automatic urls with backticks

Fixes rust-lang#49164.

r? @QuietMisdreavus

Run the `run-make` tests last, so more tests run on Windows when `make` is unavailable

Just rust-lang#47996 again.

r? @Mark-Simulacrum

…rom-Env, r=nikomatsakis

Implement Chalk lowering rule "Implemented-From-Env"

This extends the Chalk lowering pass with the "Implemented-From-Env" rule for generating program clauses from a trait definition as part of rust-lang#49177.

r? @nikomatsakis

fix vector fmin/fmax non-fast/fast intrinsics NaN handling

This bugs shows up in release mode tests of `stdsimd`: rust-lang/stdarch#391 . The intrinsics are thoroughly tested there for roundoff errors, NaN, and overflow behavior.

The problem was that the non-fast intrinsics where specifying `NoNaNs == true`, which meant that they don't support NaNs. This is incorrect, the non-fast intrinsics should handle NaNs properly.

Also, the "fast" intrinsics where specifying `NoNaNs == false` which meant that they support NaNs and then fast-math, which probably disables this support. This was not intended either.

I've added a comment specifying what the boolean flags do.

…richton

dpl 1.9.5 has been released, revert rust-lang#49217.

dpl 1.9.5 has been released which includes travis-ci/dpl#789, so we could move back to the standard Travis settings before that `s3-eager-autoload` branch is removed.

Don't check interpret_interner when accessing a static to fix miri mutable statics

Mutable statics don't work in my PR to fix the standalone [miri](https://github.com/solson/miri), as init_static didn't get called when the interpret_interner already contained a entry for the static, which is always immutable.

cc rust-lang/miri#364

…excrichton

Deprecate the AsciiExt trait in favor of inherent methods

The trait and some of its methods are stable and will remain.
Some of the newer methods are unstable and can be removed later.

Fixes rust-lang#39658

…Misdreavus

Make Atomic doc examples specific to each type

Fixes rust-lang#49018.

… r=Mark-Simulacrum

Bump racer and home

This removes 10 dependencies from the build 🎉

Update RELEASES.md for 1.25.0

[rendered](https://github.com/Aaronepower/rust/blob/master/RELEASES.md)