Auto merge of #73265 - mark-i-m:mv-std, r=<try>tmp-nightly

mv std libs to library/

This is the first step in refactoring the directory layout of this repository, with further followup steps planned (but not done yet).

Background: currently, all crates are under src/, without nested src directories and with the unconventional `lib*` prefixes (e.g., `src/libcore/lib.rs`). This directory structures is not idiomatic and makes the `src/` directory rather overwhelming. To improve contributor experience and make things a bit more approachable, we are reorganizing the repo a bit.

In this PR, we move the standard libs (basically anything that is "runtime", as opposed to part of the compiler, build system, or one of the tools, etc). The new layout moves these libraries to a new `library/` directory in the root of the repo. Additionally, we remove the `lib*` prefixes and add nested `src/` directories.  The other crates/tools in this repo are not touched. So in summary:

```
library/<crate>/src/*.rs
src/<all the rest>     // unchanged
```

where `<crate>` is:
- core
- alloc
- std
- test
- proc_macro
- panic_abort
- panic_unwind
- profiler_builtins
- term
- unwind
- rtstartup
- backtrace
- rustc-std-workspace-*

There was a lot of discussion about this and a few rounds of compiler team approvals, FCPs, MCPs, and nominations. The original MCP is https://github.com/rust-lang/compiler-team/issues/298. The final approval of the compiler team was given here: https://github.com/rust-lang/rust/pull/73265#issuecomment-659498446.

The name `library` was chosen to complement a later move of the compiler crates to a `compiler/` directory. There was a lot of discussion around adding the nested `src/` directories. Note that this does increase the nesting depth (plausibly important for manual traversal of the tree, e.g., through GitHub's UI or `cd`), but this is deemed to be better as it fits the standard layout of Rust crates throughout most of the ecosystem, though there is some debate about how much this should apply to multi-crate projects. Overall, there seem to be more people in favor of nested `src/` than against.

After this PR, there are no dependencies out of the `library/` directory except on the `build_helper` (or crates.io crates).

1 files changed, 0 insertions, 155 deletions

diff --git a/src/libstd/sys/vxworks/thread.rs b/src/libstd/sys/vxworks/thread.rs
deleted file mode 100644
index 24a2e0f965d..00000000000
--- a/src/libstd/sys/vxworks/thread.rs
+++ /dev/null
@@ -1,155 +0,0 @@
-use crate::cmp;
-use crate::ffi::CStr;
-use crate::io;
-use crate::mem;
-use crate::ptr;
-use crate::sys::{os, stack_overflow};
-use crate::time::Duration;
-
-pub const DEFAULT_MIN_STACK_SIZE: usize = 0x40000; // 256K
-
-pub struct Thread {
-    id: libc::pthread_t,
-}
-
-// Some platforms may have pthread_t as a pointer in which case we still want
-// a thread to be Send/Sync
-unsafe impl Send for Thread {}
-unsafe impl Sync for Thread {}
-
-// The pthread_attr_setstacksize symbol doesn't exist in the emscripten libc,
-// so we have to not link to it to satisfy emcc's ERROR_ON_UNDEFINED_SYMBOLS.
-unsafe fn pthread_attr_setstacksize(
-    attr: *mut libc::pthread_attr_t,
-    stack_size: libc::size_t,
-) -> libc::c_int {
-    libc::pthread_attr_setstacksize(attr, stack_size)
-}
-
-impl Thread {
-    // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> {
-        let p = Box::into_raw(box p);
-        let mut native: libc::pthread_t = mem::zeroed();
-        let mut attr: libc::pthread_attr_t = mem::zeroed();
-        assert_eq!(libc::pthread_attr_init(&mut attr), 0);
-
-        let stack_size = cmp::max(stack, min_stack_size(&attr));
-
-        match pthread_attr_setstacksize(&mut attr, stack_size) {
-            0 => {}
-            n => {
-                assert_eq!(n, libc::EINVAL);
-                // EINVAL means |stack_size| is either too small or not a
-                // multiple of the system page size.  Because it's definitely
-                // >= PTHREAD_STACK_MIN, it must be an alignment issue.
-                // Round up to the nearest page and try again.
-                let page_size = os::page_size();
-                let stack_size =
-                    (stack_size + page_size - 1) & (-(page_size as isize - 1) as usize - 1);
-                assert_eq!(libc::pthread_attr_setstacksize(&mut attr, stack_size), 0);
-            }
-        };
-
-        let ret = libc::pthread_create(&mut native, &attr, thread_start, p as *mut _);
-        // Note: if the thread creation fails and this assert fails, then p will
-        // be leaked. However, an alternative design could cause double-free
-        // which is clearly worse.
-        assert_eq!(libc::pthread_attr_destroy(&mut attr), 0);
-
-        return if ret != 0 {
-            // The thread failed to start and as a result p was not consumed. Therefore, it is
-            // safe to reconstruct the box so that it gets deallocated.
-            drop(Box::from_raw(p));
-            Err(io::Error::from_raw_os_error(ret))
-        } else {
-            Ok(Thread { id: native })
-        };
-
-        extern "C" fn thread_start(main: *mut libc::c_void) -> *mut libc::c_void {
-            unsafe {
-                // Next, set up our stack overflow handler which may get triggered if we run
-                // out of stack.
-                let _handler = stack_overflow::Handler::new();
-                // Finally, let's run some code.
-                Box::from_raw(main as *mut Box<dyn FnOnce()>)();
-            }
-            ptr::null_mut()
-        }
-    }
-
-    pub fn yield_now() {
-        let ret = unsafe { libc::sched_yield() };
-        debug_assert_eq!(ret, 0);
-    }
-
-    pub fn set_name(_name: &CStr) {
-        // VxWorks does not provide a way to set the task name except at creation time
-    }
-
-    pub fn sleep(dur: Duration) {
-        let mut secs = dur.as_secs();
-        let mut nsecs = dur.subsec_nanos() as _;
-
-        // If we're awoken with a signal then the return value will be -1 and
-        // nanosleep will fill in `ts` with the remaining time.
-        unsafe {
-            while secs > 0 || nsecs > 0 {
-                let mut ts = libc::timespec {
-                    tv_sec: cmp::min(libc::time_t::MAX as u64, secs) as libc::time_t,
-                    tv_nsec: nsecs,
-                };
-                secs -= ts.tv_sec as u64;
-                if libc::nanosleep(&ts, &mut ts) == -1 {
-                    assert_eq!(os::errno(), libc::EINTR);
-                    secs += ts.tv_sec as u64;
-                    nsecs = ts.tv_nsec;
-                } else {
-                    nsecs = 0;
-                }
-            }
-        }
-    }
-
-    pub fn join(self) {
-        unsafe {
-            let ret = libc::pthread_join(self.id, ptr::null_mut());
-            mem::forget(self);
-            assert!(ret == 0, "failed to join thread: {}", io::Error::from_raw_os_error(ret));
-        }
-    }
-
-    pub fn id(&self) -> libc::pthread_t {
-        self.id
-    }
-
-    pub fn into_id(self) -> libc::pthread_t {
-        let id = self.id;
-        mem::forget(self);
-        id
-    }
-}
-
-impl Drop for Thread {
-    fn drop(&mut self) {
-        let ret = unsafe { libc::pthread_detach(self.id) };
-        debug_assert_eq!(ret, 0);
-    }
-}
-
-#[cfg_attr(test, allow(dead_code))]
-pub mod guard {
-    use crate::ops::Range;
-    pub type Guard = Range<usize>;
-    pub unsafe fn current() -> Option<Guard> {
-        None
-    }
-    pub unsafe fn init() -> Option<Guard> {
-        None
-    }
-    pub unsafe fn deinit() {}
-}
-
-fn min_stack_size(_: *const libc::pthread_attr_t) -> usize {
-    libc::PTHREAD_STACK_MIN
-}