remove 32-bit arm HelenOS for now

See also notes in the PR, I was unable to run anything non-trivial on ARM HelenOS, there are issues
with the linker/loader, incomplete support of atomics, and overall a lot of confusion about
the precise version of ARM architecture that the HelenOS builds target.

Author: mvolfik

compiler/rustc_target/src/spec/mod.rs

@@ -1842,7 +1842,6 @@ supported_targets! {
     ("x86_64-unknown-haiku", x86_64_unknown_haiku),
 
     ("aarch64-unknown-helenos", aarch64_unknown_helenos),
-    ("armv5te-unknown-helenos-eabi", armv5te_unknown_helenos_eabi),
     ("i686-unknown-helenos", i686_unknown_helenos),
     ("powerpc-unknown-helenos", powerpc_unknown_helenos),
     ("sparc64-unknown-helenos", sparc64_unknown_helenos),

compiler/rustc_target/src/spec/targets/armv5te_unknown_helenos_eabi.rs

@@ -34,7 +34,6 @@ pub struct Finder {
 // Targets can be removed from this list once they are present in the stage0 compiler (usually by updating the beta compiler of the bootstrap).
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     "aarch64-unknown-helenos",
-    "armv5te-unknown-helenos-eabi",
     "i686-unknown-helenos",
     "x86_64-unknown-helenos",
     "powerpc-unknown-helenos",

src/bootstrap/src/core/sanity.rs

@@ -283,7 +283,6 @@ target | std | host | notes
 [`armv4t-none-eabi`](platform-support/armv4t-none-eabi.md) | * |  | Bare Armv4T
 `armv4t-unknown-linux-gnueabi` | ? |  | Armv4T Linux
 [`armv5te-none-eabi`](platform-support/armv5te-none-eabi.md) | * |  | Bare Armv5TE
-[`armv5te-unknown-helenos-eabi`](platform-support/helenos.md) | ✓ |  | Armv5TE HelenOS (see docs for pending issues)
 `armv5te-unknown-linux-uclibceabi` | ? |  | Armv5TE Linux with uClibc
 [`armv6-unknown-freebsd`](platform-support/freebsd.md) | ✓ | ✓ | Armv6 FreeBSD
 [`armv6-unknown-netbsd-eabihf`](platform-support/netbsd.md) | ✓ | ✓ | Armv6 NetBSD w/hard-float

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

@@ -12,15 +12,11 @@ Target triplets available:
 - `powerpc-unknown-helenos`
 - `aarch64-unknown-helenos`
 - `i686-unknown-helenos`*
-- `armv5te-unknown-helenos`*
 
-Support of the latter two platforms is available in the compiler, however, the toolchains are not fully functional:
 
-- On i686, some portions of native HelenOS libraries run into issues due to vector instructions accessing variables from stack that seems
+On i686, some portions of native HelenOS libraries run into issues due to vector instructions accessing variables from the stack that seems
 to be misaligned. It is not clear if this is fault of HelenOS or Rust. Most programs work, but for example calling `ui_window_create` from HelenOS
 libui does not work.
-- On 32-bit Arm, HelenOS libc is missing atomic primitives, and even after attempting to fill them, the resulting executables weren't functional,
-again for reasons that weren't fully understood yet.
 
 ## Target maintainers
 

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

@@ -118,9 +118,6 @@
 //@ revisions: armv5te_none_eabi
 //@ [armv5te_none_eabi] compile-flags: --target armv5te-none-eabi
 //@ [armv5te_none_eabi] needs-llvm-components: arm
-//@ revisions: armv5te_unknown_helenos_eabi
-//@ [armv5te_unknown_helenos_eabi] compile-flags: --target armv5te-unknown-helenos-eabi
-//@ [armv5te_unknown_helenos_eabi] needs-llvm-components: arm
 //@ revisions: armv5te_unknown_linux_gnueabi
 //@ [armv5te_unknown_linux_gnueabi] compile-flags: --target armv5te-unknown-linux-gnueabi
 //@ [armv5te_unknown_linux_gnueabi] needs-llvm-components: arm