This commit adds support to the build system to execute test suites that cannot
run natively but can instead run inside of a QEMU emulator. A proof-of-concept
builder was added for the `arm-unknown-linux-gnueabihf` target to show off how
this might work.

In general the architecture is to have a server running inside of the emulator
which a local client connects to. The protocol between the server/client
supports compiling tests on the host and running them on the target inside the
emulator.

Closes rust-lang#33114

Fixes rust-lang#34798

This is apparently a regression from 1.14.0 to 1.15.0. Previously we
passed `-fPIC` to C compilers on i686 targets, but the `gcc` crate
apparently [explicitly] didn't do this. I don't recall why that was
avoided but it was [previously passed by the makefiles][mk] and this
seems to have [caused a regression][regression] in Firefox, so this
commit reverts back to passing `-fPIC`.

[explicitly]: rust-lang/cc-rs@362bdf20
[mk]: https://github.com/rust-lang/rust/blob/c781fc4a/mk/cfg/i686-unknown-linux-gnu.mk#L11
[regression]: https://bugzilla.mozilla.org/show_bug.cgi?id=1336155

Previously AdtDef variants contained ConstInt for each discriminant, which did not really reflect
the actual type of the discriminants. Moving the type into AdtDef allows to easily put the type
into metadata and also saves bytes from ConstVal overhead for each discriminant.

Also arguably the code is cleaner now :)

This removes another special case of Switch by replacing it with the more general SwitchInt. While
this is more clunky currently, there’s no reason we can’t make it nice (and efficient) to use.

Also use a Cow to avoid full Vec for all SwitchInts

First example of optimisation that applies to many more cases than originally.

Previously it used to build a switch in a way that didn’t preserve the invariat of SwitchInt. Now
it builds it in an optimal way too, where otherwise branch becomes all the branches which did not
have partial variant drops.

This ends up not really mattering because we generate a plain conditional branch in LLVM either
way.

Constructs a TerminatorKind::SwitchInt for an equivalent conditional true-false branch.

Additionally, revert unnecessary changes to ty::layout

And libcore/benches

cc rust-lang#39569 -- almost certainly a fix for that

This commit deletes the old build system located in the `mk` folder as it's now
been obsoleted for two cycles and is replaced by rustbuild.

This commit deletes swaths of the configure script related to the old build
system which are now no longer needed when using rustbuild.

We no longer need these builders as we're no longer testing the old build
system.

These are all now no longer needed that we've only got rustbuild in tree.

Some of these have long since expired, some are no longer in use now that we've
jettisoned the makefiles, but none of them should be needed any more.

* Add version info to channel.rs as main.mk is no longer available
* Update `Makefile.in` used with bootstrap to not try to require `mk/util.mk`
* Update the `dist` target to avoid the makefile pieces

Don't re-run tests in compiletest if all the inputs haven't changed, manage
stamp files in the output directory.

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

* Moved algorithm explanation to module docs
* Added ``` before and after the examples
* Explanation of the `rbox`, `ibox` and `cbox` names
* Added docs about the breaking types to `Breaks`

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

Clarify and reorganize.

Add the section for the bookshelf. More to come here in the near future!

Part of rust-lang#39588

This landed on beta in rust-lang#39546 and this is bringing the patch back to master.

Right now all Cargo release tarballs are 'nightly', they're not on the standard
channels yet.

Even more SNAP cleanup.

This is much nicer for callers who want to short-circuit real I/O errors
with `?`, because they can write this

    if let Some(status) = foo.try_wait()? {
        ...
    } else {
        ...
    }

instead of this

    match foo.try_wait() {
        Ok(status) => {
            ...
        }
        Err(err) if err.kind() == io::ErrorKind::WouldBlock => {
            ...
        }
        Err(err) => return Err(err),
    }

The original design of `try_wait` was patterned after the `Read` and
`Write` traits, which support both blocking and non-blocking
implementations in a single API. But since `try_wait` is never blocking,
it makes sense to optimize for the non-blocking case.

Tracking issue: rust-lang#38903

…ved from the current compiler version

* Move to a separate float mod
* Add more tests for f64 f32 lower exp upper exp
* Use assert_eq for a clearer error message

…r-chosen names.

It claims to accept most GNU linker options, but in fact most of them
have no effect and instead it requires some special options which are
easier to handle in a separate trait.

Currently added:
 - `export_symbols`: works on executables as special Emscripten case
since staticlibs/dylibs aren't compiled to JS, while exports are
required to be accessible from JS.
Fixes rust-lang#39171.
 - `optimize` - translates Rust's optimization level to Emscripten
optimization level (whether passed via `-C opt-level=...` or `-O...`).
Fixes rust-lang#36899.
 - `debuginfo` - translates debug info; Emscripten has 5 debug levels
while Rust has 3, so chose to translate `-C debuginfo=1` to `-g3`
(preserves whitespace, variable and function names for easy debugging).
Fixes rust-lang#36901.
 - `no_default_libraries` - tells Emscripten to exlude `memcpy` and co.

Prevents stale artifacts from sticking around by accident!

Added Default impl to PathBuf

Improve error message for uninferrable types rust-lang#38812

Hello,

I tried to improve the error message for uninferrable types. The error code is `E0282`.

```rust

error[E0282]: type annotations needed
 --> /home/cengizIO/issue38812.rs:2:11
  |
2 |   let x = vec![];
  |       -   ^^^^^^ cannot infer type for `T`
  |       |
  |       consider giving `x` a type
  |
  = note: this error originates in a macro outside of the current crate
```

and

```rust

error[E0282]: type annotations needed
 --> /home/cengizIO/issue38812.rs:2:15
  |
2 |   let (x,) = (vec![],);
  |       ----    ^^^^^^ cannot infer type for `T`
  |       |
  |       consider giving a type to pattern
  |
  = note: this error originates in a macro outside of the current crate
```

Rust compiler now tries to find uninferred `local`s with type `_` and adds them into the error message.

I'm probably wrong on wording that I used. Please feel free to suggest better alternatives.

Thanks @nikomatsakis for mentoring 🍺

Any comments/feedback is more than welcome!

Thank you

…crichton

A few ergonomic From impls for SocketAddr/IpAddr

My main motivation is removing things like this: `"127.0.0.1:3000".parse().unwrap()`. Instead, this now works: `SocketAddr::from(([127, 0, 0, 1], 3000))` or even `([127, 0, 0, 1], 3000).into())` when passing to a function.

reference: clarify #[cfg] section

Closes rust-lang#39370, but maybe we (or clippy) should add a warning too.

Add support for test suites emulated in QEMU

This commit adds support to the build system to execute test suites that cannot
run natively but can instead run inside of a QEMU emulator. A proof-of-concept
builder was added for the `arm-unknown-linux-gnueabihf` target to show off how
this might work.

In general the architecture is to have a server running inside of the emulator
which a local client connects to. The protocol between the server/client
supports compiling tests on the host and running them on the target inside the
emulator.

Closes rust-lang#33114

Add i686-unknown-netbsdelf target

…rson

Delete the makefile build system

This PR deletes the makefile build system in favor of the rustbuild build system. The beta has now been branched so 1.16 will continue to be buildable from the makefiles, but going forward 1.17 will only be buildable with rustbuild.

Rustbuild has been the default build system [since 1.15.0](rust-lang#37817) and the makefiles were [proposed for deletion](https://internals.rust-lang.org/t/proposal-for-promoting-rustbuild-to-official-status/4368) at this time back in November of last year.

And now with the deletion of these makefiles we can start getting those sweet sweet improvements of using crates.io crates in the compiler!

Conversions between slices and boxes

This allows conversion for `Copy` slices, `str`, and `CStr` into their boxed counterparts.

This also adds the method `CString::into_boxed_c_str`.

I would like to add similar implementations for `OsStr` as well, but I have not figured out how.

…nikomatsakis

[MIR] SwitchInt Everywhere

Something I’ve been meaning to do for a very long while. This PR essentially gets rid of 3 kinds of conditional branching and only keeps the most general one – `SwitchInt`. Primary benefits are such that dealing with MIR now does not involve dealing with 3 different ways to do conditional control flow. On the other hand, constructing a `SwitchInt` currently requires more code than what previously was necessary to build an equivalent `If` terminator. Something trivially “fixable” with some constructor methods somewhere (MIR needs stuff like that badly in general).

Some timings (tl;dr: slightly faster¹ (unexpected), but also uses slightly more memory at peak (expected)):

¹: Not sure if the speed benefits are because of LLVM liking the generated code better or the compiler itself getting compiled better. Either way, its a net benefit. The CORE and SYNTAX timings done for compilation without optimisation.

```
AFTER:
Building stage1 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 31.50 secs
    Finished release [optimized] target(s) in 31.42 secs
Building stage1 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 439.56 secs
    Finished release [optimized] target(s) in 435.15 secs

CORE: 99% (24.81 real, 0.13 kernel, 24.57 user); 358536k resident
CORE: 99% (24.56 real, 0.15 kernel, 24.36 user); 359168k resident
SYNTAX: 99% (49.98 real, 0.48 kernel, 49.42 user); 653416k resident
SYNTAX: 99% (50.07 real, 0.58 kernel, 49.43 user); 653604k resident

BEFORE:
Building stage1 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 31.84 secs
Building stage1 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 451.17 secs

CORE: 99% (24.66 real, 0.20 kernel, 24.38 user); 351096k resident
CORE: 99% (24.36 real, 0.17 kernel, 24.18 user); 352284k resident
SYNTAX: 99% (52.24 real, 0.56 kernel, 51.66 user); 645544k resident
SYNTAX: 99% (51.55 real, 0.48 kernel, 50.99 user); 646428k resident
```

cc @nikomatsakis @eddyb

…c, r=steveklabnik

Fix short hand struct doc

Don't want to discredit @HnGiang effort on this issue.

I just want to lend a hand to fix this issue rust-lang#38830, it is a very nice feature and is seemingly completed.

Fixes rust-lang#39096

r? @steveklabnik

lint/ctypes: Don't warn on sized structs with PhantomData.

Fixes rust-lang#34798

doc comment rewording

Add Emscripten-specific linker

Emscripten claims to accept most GNU linker options, but in fact most of `-Wl,...` are useless for it and instead it requires some additional special options which are easier to handle in a separate trait.

Currently added:
 - `export_symbols`: works on executables as special Emscripten case since staticlibs/dylibs aren't compiled to JS, while exports are required to be accessible from JS.
Fixes rust-lang#39171.
 - `optimize` - translates Rust's optimization level to Emscripten optimization level (whether passed via `-C opt-level=...` or `-O...`).
Fixes rust-lang#36899.
 - `debuginfo` - translates debug info; Emscripten has 5 debug levels while Rust has 3, so chose to translate `-C debuginfo=1` to `-g3` (preserves whitespace, variable and function names for easy debugging).
Fixes rust-lang#36901.
 - `no_default_libraries` - tells Emscripten to exclude `memcpy` and co.

TODO (in future PR): dynamic linking via `SIDE_MODULE` / `MAIN_MODULE` mechanism.

make Child::try_wait return io::Result<Option<ExitStatus>>

This is much nicer for callers who want to short-circuit real I/O errors
with `?`, because they can write this

    if let Some(status) = foo.try_wait()? {
        ...
    } else {
        ...
    }

instead of this

    match foo.try_wait() {
        Ok(status) => {
            ...
        }
        Err(err) if err.kind() == io::ErrorKind::WouldBlock => {
            ...
        }
        Err(err) => return Err(err),
    }

The original design of `try_wait` was patterned after the `Read` and
`Write` traits, which support both blocking and non-blocking
implementations in a single API. But since `try_wait` is never blocking,
it makes sense to optimize for the non-blocking case.

Tracking issue: rust-lang#38903

Pass -fPIC to native compiles on 32-bit

This is apparently a regression from 1.14.0 to 1.15.0. Previously we
passed `-fPIC` to C compilers on i686 targets, but the `gcc` crate
apparently [explicitly] didn't do this. I don't recall why that was
avoided but it was [previously passed by the makefiles][mk] and this
seems to have [caused a regression][regression] in Firefox, so this
commit reverts back to passing `-fPIC`.

[explicitly]: rust-lang/cc-rs@362bdf20
[mk]: https://github.com/rust-lang/rust/blob/c781fc4a/mk/cfg/i686-unknown-linux-gnu.mk#L11
[regression]: https://bugzilla.mozilla.org/show_bug.cgi?id=1336155

…fried

Change deprecation warning to indicate custom derive support was removed

I'm very new to Rust and the message was confusing to me (using nightly and not really sure if I was > 1.15 or not).

A few documentation improvements for `syntax::print::pp`

* Moved algorithm explanation to module docs
* Added ``` before and after the examples
* Explanation of the `rbox`, `ibox` and `cbox` names
* Added docs about the breaking types to `Breaks`

…lexcrichton

Extract collections benchmarks to libcollections/bench

Good suggestion from @stjepang rust-lang#39484 (comment)

r? @alexcrichton

… r=michaelwoerister

Handle the case where an intermediate node can't be recreated

This solution grows the graph, but this is quite the corner case.

r? @michaelwoerister

…, r=nikomatsakis

back: Limit the number of LLVM worker threads.

This should fix issue rust-lang#39568.
Also see rust-lang#39280.

r? @nikomatsakis

rustbuild: support setting verbosity in config.toml

Most if not all the configuration is settable trhough config.toml but the verbosity isn't yet.

This avoids having to pass -v to x.py on each command if you want verbosity to be always on.

…, r=frewsxcv

Re-write the doc index page

Clarify and reorganize.

Add the section for the bookshelf. More to come here in the near future!

Part of rust-lang#39588

…_file, r=alexcrichton

Display correct filename with --test option

Fixes rust-lang#39592.

With the current files:

```rust
pub mod foo;

/// This is a Foo;
///
/// ```
/// println!("baaaaaar");
/// ```
pub struct Foo;

/// This is a Bar;
///
/// ```
/// println!("fooooo");
/// ```
pub struct Bar;
```

```rust
// note the whitespaces
/// ```
/// println!("foo");
/// ```
pub fn foo() {}
```

It displays:

```
./build/x86_64-apple-darwin/stage1/bin/rustdoc --test test.rs

running 3 tests
test test.rs - line 13 ... ok
test test.rs - line 5 ... ok
test foo.rs - line 2 ... ok

test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured
```

```

` ``
println!("lol");
` ``

asdjnfasd

asd
```

It displays:

```
./build/x86_64-apple-darwin/stage1/bin/rustdoc --test foo.md

running 1 test
test <input> - line 3 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured
```

r? @alexcrichton

Fix branch name Cargo's downloaded from

This landed on beta in rust-lang#39546 and this is bringing the patch back to master.

…brson

Fix a manifest-generation bug on beta

Right now all Cargo release tarballs are 'nightly', they're not on the standard
channels yet.

…aarch64-unknown-freebsd, r=alexcrichton

liblibc: Update to include `aarch64-unknown-freebsd` support

Fix ICE when accessing mutably an immutable enum

Fix rust-lang#39544.

Unignore u128 test for stage 0,1

Even more SNAP cleanup.

Follow-up of rust-lang#39519.

Sorry, I didn't check twice.

Improve format float

* Move float into mod float like in test
* Add more tests for f64 f32, lower exp, upper exp, which can come if handy in the future if we want refactor further
* Use `assert_eq` for clearer error messages