Fixes rust-lang#68104

Previous, we were encoding AnonConst as a regular Const, causing us to
treat them differently after being deserialized in another compilation
session.

This will run all tests for `riscv64gc-unknown-linux-gnu` in a QEMU
instance. This is based upon the armhf QEMU test image.

Thanks to jfrimmel for pointing this out

Co-authored-by: J. Frimmel <31166235+jfrimmel@users.noreply.github.com>

In our GitHub Actions setup macOS is too unreliable to gate on it, but
the other builders work fine. This commit splits the macOS builders into
a separate job (called auto-fallible), allowing us to gate on the auto
job without failing due to macOS spurious failures.

The build is not actually needed often, and it can be added back on a
case-by-case basis if a specific PR needs access to it.

Insufficient sanitization of the x87 FPU tag word in the trusted enclave runtime allowed unprivileged adversaries in the containing host application to induce incoherent or unexpected results for ABI-compliant compiled enclave application code that uses the x87 FPU.

Vulnerability was disclosed to us by Fritz Alder, Jo Van Bulck, David Oswald and Frank Piessens

…o io traits

…r=varkor

Properly encode AnonConst into crate metadata

Fixes rust-lang#68104

Previous, we were encoding AnonConst as a regular Const, causing us to
treat them differently after being deserialized in another compilation
session.

RISC-V Emulated Testing

Adds a disabled docker image on which to run RISC-V tests. Based on the armhf image.

Test using
```
./src/ci/docker/run.sh riscv64gc-linux
```

cc: @msizanoen1

…oli-obk

Remove use of specialization from librustc_arena

This reworks the macro so that specialization, `transmute` and `#[marker]` are not used.

r? @oli-obk

…ulacrum

Update CFGuard syntax

Update the naming and syntax of the control-flow-guard option, as discussed in rust-lang#68793.

r? @Mark-Simulacrum

Update bootstrap to rustc 1.45.0-beta.2 (1dc0f6d 2020-06-15)

Pulls in changes from rust-lang#73326.

Closes rust-lang#73286

Update cargo

3 commits in 79c769c3d7b4c2cf6a93781575b7f592ef974255..089cbb80b73ba242efdcf5430e89f63fa3b5328d
2020-06-11 22:13:37 +0000 to 2020-06-15 14:38:34 +0000
- Support linker with -Zdoctest-xcompile. (rust-lang/cargo#8359)
- Fix doctests not running with --target=HOST. (rust-lang/cargo#8358)
- Allow passing a registry index url directly to `cargo install` (rust-lang/cargo#8344)

…ark-Simulacrum

ci: allow gating GHA on everything but macOS

In our GitHub Actions setup macOS is too unreliable to gate on it, but the other builders work fine. This commit splits the macOS builders into a separate job (called `auto-fallible`), allowing us to gate on the auto job without failing due to macOS spurious failures.

cc rust-lang/rust-central-station#848
r? @Mark-Simulacrum

…ark-Simulacrum

ci: disable alt build during try builds

The alt build is not actually needed often, and it can be added back on a case-by-case basis if a specific PR needs access to it.

This will free up a builder.

r? @Mark-Simulacrum

…jethrogb

Prevent attacker from manipulating FPU tag word used in SGX enclave

Insufficient sanitization of the x87 FPU tag word in the trusted enclave runtime allowed unprivileged adversaries in the containing host application to induce incoherent or unexpected results for ABI-compliant compiled enclave application code that uses the x87 FPU.

Vulnerability was disclosed to us by Fritz Alder, Jo Van Bulck, David Oswald and Frank Piessens

cc: @jethrogb

Converted all platform-specific stdin/stdout/stderr implementations to use io:: traits

Currently, some of the platform-specific standard streams (`src/libstd/sys/*/stdio.rs`) manually implement parts of the `io::Write` interface directly as methods on the struct, rather than by actually implementing the trait. There doesn't seem to be any reason for this, other than an unused advantage of `fn write(&self, ...)` instead of `fn write(&mut self, ...)`.

Unfortunately, this means that those implementations don't have the default-implemented io methods, like `read_exact` and `write_all`. This caused rust-lang#72705, which adds forwarding methods to the user-facing standard stream implementations, to fail to compile on those platforms.

This change converts *all* such standard stream structs to use the standard library traits. This change should not cause any breakages, because the changed types are not publicly exported, and in fact are only ever used in `src/libstd/io/stdio.rs`.