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, 110 deletions

diff --git a/src/libstd/sys/windows/thread.rs b/src/libstd/sys/windows/thread.rs
deleted file mode 100644
index 38839ea5e90..00000000000
--- a/src/libstd/sys/windows/thread.rs
+++ /dev/null
@@ -1,110 +0,0 @@
-use crate::ffi::CStr;
-use crate::io;
-use crate::ptr;
-use crate::sys::c;
-use crate::sys::handle::Handle;
-use crate::sys::stack_overflow;
-use crate::time::Duration;
-
-use libc::c_void;
-
-use super::to_u16s;
-
-pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024;
-
-pub struct Thread {
-    handle: Handle,
-}
-
-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);
-
-        // FIXME On UNIX, we guard against stack sizes that are too small but
-        // that's because pthreads enforces that stacks are at least
-        // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
-        // just that below a certain threshold you can't do anything useful.
-        // That threshold is application and architecture-specific, however.
-        // Round up to the next 64 kB because that's what the NT kernel does,
-        // might as well make it explicit.
-        let stack_size = (stack + 0xfffe) & (!0xfffe);
-        let ret = c::CreateThread(
-            ptr::null_mut(),
-            stack_size,
-            thread_start,
-            p as *mut _,
-            c::STACK_SIZE_PARAM_IS_A_RESERVATION,
-            ptr::null_mut(),
-        );
-
-        return if ret as usize == 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::last_os_error())
-        } else {
-            Ok(Thread { handle: Handle::new(ret) })
-        };
-
-        extern "system" fn thread_start(main: *mut c_void) -> c::DWORD {
-            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()>)();
-            }
-            0
-        }
-    }
-
-    pub fn set_name(name: &CStr) {
-        if let Ok(utf8) = name.to_str() {
-            if let Ok(utf16) = to_u16s(utf8) {
-                unsafe {
-                    c::SetThreadDescription(c::GetCurrentThread(), utf16.as_ptr());
-                };
-            };
-        };
-    }
-
-    pub fn join(self) {
-        let rc = unsafe { c::WaitForSingleObject(self.handle.raw(), c::INFINITE) };
-        if rc == c::WAIT_FAILED {
-            panic!("failed to join on thread: {}", io::Error::last_os_error());
-        }
-    }
-
-    pub fn yield_now() {
-        // This function will return 0 if there are no other threads to execute,
-        // but this also means that the yield was useless so this isn't really a
-        // case that needs to be worried about.
-        unsafe {
-            c::SwitchToThread();
-        }
-    }
-
-    pub fn sleep(dur: Duration) {
-        unsafe { c::Sleep(super::dur2timeout(dur)) }
-    }
-
-    pub fn handle(&self) -> &Handle {
-        &self.handle
-    }
-
-    pub fn into_handle(self) -> Handle {
-        self.handle
-    }
-}
-
-#[cfg_attr(test, allow(dead_code))]
-pub mod guard {
-    pub type Guard = !;
-    pub unsafe fn current() -> Option<Guard> {
-        None
-    }
-    pub unsafe fn init() -> Option<Guard> {
-        None
-    }
-}