Rollup merge of #101780 - chriswailes:android-platform, r=joshtriplett

Add a platform support document for Android

r? ``@joshtriplett``

Author: matthiaskrgr

src/doc/rustc/src/SUMMARY.md

@@ -24,6 +24,7 @@
     - [armv6k-nintendo-3ds](platform-support/armv6k-nintendo-3ds.md)
     - [armv7-unknown-linux-uclibceabi](platform-support/armv7-unknown-linux-uclibceabi.md)
     - [armv7-unknown-linux-uclibceabihf](platform-support/armv7-unknown-linux-uclibceabihf.md)
+    - [\*-android and \*-androideabi](platform-support/android.md)
     - [\*-fuchsia](platform-support/fuchsia.md)
     - [\*-kmc-solid_\*](platform-support/kmc-solid.md)
     - [m68k-unknown-linux-gnu](platform-support/m68k-unknown-linux-gnu.md)

src/doc/rustc/src/platform-support.md

@@ -125,17 +125,17 @@ target | std | notes
 `aarch64-apple-ios` | ✓ | ARM64 iOS
 [`aarch64-apple-ios-sim`](platform-support/aarch64-apple-ios-sim.md) | ✓ | Apple iOS Simulator on ARM64
 `aarch64-fuchsia` | ✓ | ARM64 Fuchsia
-`aarch64-linux-android` | ✓ | ARM64 Android
+[`aarch64-linux-android`](platform-support/android.md) | ✓ | ARM64 Android
 `aarch64-unknown-none-softfloat` | * | Bare ARM64, softfloat
 `aarch64-unknown-none` | * | Bare ARM64, hardfloat
-`arm-linux-androideabi` | ✓ | ARMv7 Android
+[`arm-linux-androideabi`](platform-support/android.md) | ✓ | ARMv7 Android
 `arm-unknown-linux-musleabi` | ✓ | ARMv6 Linux with MUSL
 `arm-unknown-linux-musleabihf` | ✓ | ARMv6 Linux with MUSL, hardfloat
 `armebv7r-none-eabi` | * | Bare ARMv7-R, Big Endian
 `armebv7r-none-eabihf` | * | Bare ARMv7-R, Big Endian, hardfloat
 `armv5te-unknown-linux-gnueabi` | ✓ | ARMv5TE Linux (kernel 4.4, glibc 2.23)
 `armv5te-unknown-linux-musleabi` | ✓ | ARMv5TE Linux with MUSL
-`armv7-linux-androideabi` | ✓ | ARMv7a Android
+[`armv7-linux-androideabi`](platform-support/android.md) | ✓ | ARMv7a Android
 `armv7-unknown-linux-gnueabi` | ✓ |ARMv7 Linux (kernel 4.15, glibc 2.27)
 `armv7-unknown-linux-musleabi` | ✓ |ARMv7 Linux with MUSL
 `armv7-unknown-linux-musleabihf` | ✓ | ARMv7 Linux with MUSL, hardfloat
@@ -146,7 +146,7 @@ target | std | notes
 `i586-pc-windows-msvc` | * | 32-bit Windows w/o SSE
 `i586-unknown-linux-gnu` | ✓ | 32-bit Linux w/o SSE (kernel 4.4, glibc 2.23)
 `i586-unknown-linux-musl` | ✓ | 32-bit Linux w/o SSE, MUSL
-`i686-linux-android` | ✓ | 32-bit x86 Android
+[`i686-linux-android`](platform-support/android.md) | ✓ | 32-bit x86 Android
 `i686-unknown-freebsd` | ✓ | 32-bit FreeBSD
 `i686-unknown-linux-musl` | ✓ | 32-bit Linux with MUSL
 `mips-unknown-linux-musl` | ✓ | MIPS Linux with MUSL
@@ -165,7 +165,7 @@ target | std | notes
 `thumbv7em-none-eabi` | * | Bare Cortex-M4, M7
 `thumbv7em-none-eabihf` | * | Bare Cortex-M4F, M7F, FPU, hardfloat
 `thumbv7m-none-eabi` | * | Bare Cortex-M3
-`thumbv7neon-linux-androideabi` | ✓ | Thumb2-mode ARMv7a Android with NEON
+[`thumbv7neon-linux-androideabi`](platform-support/android.md) | ✓ | Thumb2-mode ARMv7a Android with NEON
 `thumbv7neon-unknown-linux-gnueabihf` | ✓ | Thumb2-mode ARMv7a Linux with NEON (kernel 4.4, glibc 2.23)
 `thumbv8m.base-none-eabi` | * | ARMv8-M Baseline
 `thumbv8m.main-none-eabi` | * | ARMv8-M Mainline
@@ -176,7 +176,7 @@ target | std | notes
 `x86_64-apple-ios` | ✓ | 64-bit x86 iOS
 [`x86_64-fortanix-unknown-sgx`](platform-support/x86_64-fortanix-unknown-sgx.md) | ✓ | [Fortanix ABI] for 64-bit Intel SGX
 `x86_64-fuchsia` | ✓ | 64-bit Fuchsia
-`x86_64-linux-android` | ✓ | 64-bit x86 Android
+[`x86_64-linux-android`](platform-support/android.md) | ✓ | 64-bit x86 Android
 `x86_64-pc-solaris` | ✓ | 64-bit Solaris 10/11, illumos
 `x86_64-unknown-linux-gnux32` | ✓ | 64-bit Linux (x32 ABI) (kernel 4.15, glibc 2.27)
 [`x86_64-unknown-none`](platform-support/x86_64-unknown-none.md) | * | Freestanding/bare-metal x86_64, softfloat

src/doc/rustc/src/platform-support/android.md

@@ -0,0 +1,45 @@
+# *-linux-android and *-linux-androideabi
+
+**Tier: 2**
+
+[Android] is a mobile operating system built on top of the Linux kernel.
+
+[Android]: https://source.android.com/
+
+## Target maintainers
+
+- Chris Wailes ([@chriswailes](https://github.com/chriswailes))
+- Matthew Maurer ([@maurer](https://github.com/maurer))
+- Martin Geisler ([@mgeisler](https://github.com/mgeisler))
+
+## Requirements
+
+This target is cross-compiled from a host environment. Development may be done
+from the [source tree] or using the Android NDK.
+
+[source tree]: https://source.android.com/docs/setup/build/downloading
+
+Android targets support std. Generated binaries use the ELF file format.
+
+## NDK/API Update Policy
+
+Rust will support the most recent Long Term Support (LTS) Android Native
+Development Kit (NDK).  By default Rust will support all API levels supported
+by the NDK, but a higher minimum API level may be required if deemed necessary.
+
+## Building the target
+
+To build Rust binaries for Android you'll need a copy of the most recent LTS
+edition of the [Android NDK].  Supported Android targets are:
+
+* aarch64-linux-android
+* arm-linux-androideabi
+* armv7-linux-androideabi
+* i686-linux-android
+* thumbv7neon-linux-androideabi
+* x86_64-linux-android
+
+[Android NDK]: https://developer.android.com/ndk/downloads
+
+A list of all supported targets can be found
+[here](https://doc.rust-lang.org/rustc/platform-support.html)