Merge sys_common::rt into rt

Author: bjorn3

library/std/src/lib.rs

@@ -518,8 +518,12 @@ pub mod task {
     pub use alloc::task::*;
 }
 
-// Platform-abstraction modules
+// The runtime entry point and a few unstable public functions used by the
+// compiler
 #[macro_use]
+pub mod rt;
+
+// Platform-abstraction modules
 mod sys_common;
 mod sys;
 
@@ -528,10 +532,6 @@ pub mod alloc;
 // Private support modules
 mod panicking;
 
-// The runtime entry point and a few unstable public functions used by the
-// compiler
-pub mod rt;
-
 #[path = "../../backtrace/src/lib.rs"]
 #[allow(dead_code, unused_attributes)]
 mod backtrace_rs;

library/std/src/process.rs

@@ -1907,7 +1907,7 @@ impl Child {
 /// [platform-specific behavior]: #platform-specific-behavior
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn exit(code: i32) -> ! {
-    crate::sys_common::rt::cleanup();
+    crate::rt::cleanup();
     crate::sys::os::exit(code)
 }
 

library/std/src/rt.rs

@@ -13,10 +13,90 @@
     issue = "none"
 )]
 #![doc(hidden)]
+#![deny(unsafe_op_in_unsafe_fn)]
+#![allow(unused_macros)]
 
 // Re-export some of our utilities which are expected by other crates.
 pub use crate::panicking::{begin_panic, begin_panic_fmt, panic_count};
 
+use crate::sync::Once;
+use crate::sys;
+use crate::sys_common::thread_info;
+use crate::thread::Thread;
+
+// One-time runtime initialization.
+// Runs before `main`.
+// SAFETY: must be called only once during runtime initialization.
+// NOTE: this is not guaranteed to run, for example when Rust code is called externally.
+#[cfg_attr(test, allow(dead_code))]
+unsafe fn init(argc: isize, argv: *const *const u8) {
+    unsafe {
+        sys::init(argc, argv);
+
+        let main_guard = sys::thread::guard::init();
+        // Next, set up the current Thread with the guard information we just
+        // created. Note that this isn't necessary in general for new threads,
+        // but we just do this to name the main thread and to give it correct
+        // info about the stack bounds.
+        let thread = Thread::new(Some("main".to_owned()));
+        thread_info::set(main_guard, thread);
+    }
+}
+
+// One-time runtime cleanup.
+// Runs after `main` or at program exit.
+// NOTE: this is not guaranteed to run, for example when the program aborts.
+pub(crate) fn cleanup() {
+    static CLEANUP: Once = Once::new();
+    CLEANUP.call_once(|| unsafe {
+        // Flush stdout and disable buffering.
+        crate::io::cleanup();
+        // SAFETY: Only called once during runtime cleanup.
+        sys::cleanup();
+    });
+}
+
+// Prints to the "panic output", depending on the platform this may be:
+// - the standard error output
+// - some dedicated platform specific output
+// - nothing (so this macro is a no-op)
+macro_rules! rtprintpanic {
+    ($($t:tt)*) => {
+        if let Some(mut out) = crate::sys::stdio::panic_output() {
+            let _ = crate::io::Write::write_fmt(&mut out, format_args!($($t)*));
+        }
+    }
+}
+
+macro_rules! rtabort {
+    ($($t:tt)*) => {
+        {
+            rtprintpanic!("fatal runtime error: {}\n", format_args!($($t)*));
+            crate::sys::abort_internal();
+        }
+    }
+}
+
+macro_rules! rtassert {
+    ($e:expr) => {
+        if !$e {
+            rtabort!(concat!("assertion failed: ", stringify!($e)));
+        }
+    };
+}
+
+macro_rules! rtunwrap {
+    ($ok:ident, $e:expr) => {
+        match $e {
+            $ok(v) => v,
+            ref err => {
+                let err = err.as_ref().map(drop); // map Ok/Some which might not be Debug
+                rtabort!(concat!("unwrap failed: ", stringify!($e), " = {:?}"), err)
+            }
+        }
+    };
+}
+
 // To reduce the generated code of the new `lang_start`, this function is doing
 // the real work.
 #[cfg(not(test))]
@@ -25,7 +105,7 @@ fn lang_start_internal(
     argc: isize,
     argv: *const *const u8,
 ) -> Result<isize, !> {
-    use crate::{mem, panic, sys, sys_common};
+    use crate::{mem, panic};
     let rt_abort = move |e| {
         mem::forget(e);
         rtabort!("initialization or cleanup bug");
@@ -41,14 +121,14 @@ fn lang_start_internal(
     // prevent libstd from accidentally introducing a panic to these functions. Another is from
     // user code from `main` or, more nefariously, as described in e.g. issue #86030.
     // SAFETY: Only called once during runtime initialization.
-    panic::catch_unwind(move || unsafe { sys_common::rt::init(argc, argv) }).map_err(rt_abort)?;
+    panic::catch_unwind(move || unsafe { init(argc, argv) }).map_err(rt_abort)?;
     let ret_code = panic::catch_unwind(move || panic::catch_unwind(main).unwrap_or(101) as isize)
         .map_err(move |e| {
             mem::forget(e);
             rtprintpanic!("drop of the panic payload panicked");
             sys::abort_internal()
         });
-    panic::catch_unwind(sys_common::rt::cleanup).map_err(rt_abort)?;
+    panic::catch_unwind(cleanup).map_err(rt_abort)?;
     ret_code
 }
 

library/std/src/sys_common/mod.rs

@@ -28,8 +28,6 @@ pub mod memchr;
 pub mod mutex;
 pub mod process;
 pub mod remutex;
-#[macro_use]
-pub mod rt;
 pub mod rwlock;
 pub mod thread;
 pub mod thread_info;