Auto merge of #141133 - matthiaskrgr:rollup-u8ndxyz, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #135808 (Implement Display for ``rustc_target::callconv::Conv``)
 - #137432 (Add as_ascii_unchecked() methods to char, u8, and str)
 - #139103 (deduplicate abort implementations)
 - #140917 (checktools.sh: fix bashism)
 - #141035 (turn lld warning on old gccs into info log)
 - #141118 (Enable rust-analyzer to go from query definition to the corresponding provider field)
 - #141121 (Only select true errors in `impossible_predicates`)
 - #141125 (check coroutines with `TypingMode::Borrowck` to avoid cyclic reasoning)
 - #141131 (Make some `match`es slightly more ergonomic in `librustdoc`)

r? `@ghost`
`@rustbot` modify labels: rollup

6 files changed, 17 insertions, 29 deletions

diff --git a/library/std/src/sys/pal/hermit/mod.rs b/library/std/src/sys/pal/hermit/mod.rs
index ea636938d70..fb8d69b7375 100644
--- a/library/std/src/sys/pal/hermit/mod.rs
+++ b/library/std/src/sys/pal/hermit/mod.rs
@@ -43,15 +43,6 @@ pub fn abort_internal() -> ! {
     unsafe { hermit_abi::abort() }
 }
 
-// This function is needed by the panic runtime. The symbol is named in
-// pre-link args for the target specification, so keep that in sync.
-#[cfg(not(test))]
-#[unsafe(no_mangle)]
-// NB. used by both libunwind and libpanic_abort
-pub extern "C" fn __rust_abort() {
-    abort_internal();
-}
-
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
 pub unsafe fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) {
diff --git a/library/std/src/sys/pal/sgx/mod.rs b/library/std/src/sys/pal/sgx/mod.rs
index 3932f64c0ef..6e43a79ddec 100644
--- a/library/std/src/sys/pal/sgx/mod.rs
+++ b/library/std/src/sys/pal/sgx/mod.rs
@@ -112,11 +112,14 @@ pub fn abort_internal() -> ! {
     abi::usercalls::exit(true)
 }
 
-// This function is needed by the panic runtime. The symbol is named in
+// This function is needed by libunwind. The symbol is named in
 // pre-link args for the target specification, so keep that in sync.
+// Note: contrary to the `__rust_abort` in `crate::rt`, this uses `no_mangle`
+//       because it is actually used from C code. Because symbols annotated with
+//       #[rustc_std_internal_symbol] get mangled, this will not lead to linker
+//       conflicts.
 #[cfg(not(test))]
 #[unsafe(no_mangle)]
-// NB. used by both libunwind and libpanic_abort
 pub extern "C" fn __rust_abort() {
     abort_internal();
 }
diff --git a/library/std/src/sys/pal/uefi/mod.rs b/library/std/src/sys/pal/uefi/mod.rs
index 78fcfcb3b77..8911a2ee519 100644
--- a/library/std/src/sys/pal/uefi/mod.rs
+++ b/library/std/src/sys/pal/uefi/mod.rs
@@ -161,14 +161,6 @@ pub fn abort_internal() -> ! {
     core::intrinsics::abort();
 }
 
-// This function is needed by the panic runtime. The symbol is named in
-// pre-link args for the target specification, so keep that in sync.
-#[cfg(not(test))]
-#[unsafe(no_mangle)]
-pub extern "C" fn __rust_abort() {
-    abort_internal();
-}
-
 /// Disable access to BootServices if `EVT_SIGNAL_EXIT_BOOT_SERVICES` is signaled
 extern "efiapi" fn exit_boot_service_handler(_e: r_efi::efi::Event, _ctx: *mut crate::ffi::c_void) {
     uefi::env::disable_boot_services();
diff --git a/library/std/src/sys/pal/windows/mod.rs b/library/std/src/sys/pal/windows/mod.rs
index 4f18c4009ab..8f54e2376eb 100644
--- a/library/std/src/sys/pal/windows/mod.rs
+++ b/library/std/src/sys/pal/windows/mod.rs
@@ -328,8 +328,12 @@ pub fn dur2timeout(dur: Duration) -> u32 {
 
 /// Use `__fastfail` to abort the process
 ///
-/// This is the same implementation as in libpanic_abort's `__rust_start_panic`. See
-/// that function for more information on `__fastfail`
+/// In Windows 8 and later, this will terminate the process immediately without
+/// running any in-process exception handlers. In earlier versions of Windows,
+/// this sequence of instructions will be treated as an access violation, which
+/// will still terminate the process but might run some exception handlers.
+///
+/// https://docs.microsoft.com/en-us/cpp/intrinsics/fastfail
 #[cfg(not(miri))] // inline assembly does not work in Miri
 pub fn abort_internal() -> ! {
     unsafe {
diff --git a/library/std/src/sys/pal/xous/mod.rs b/library/std/src/sys/pal/xous/mod.rs
index 383d031ed43..042c4ff862f 100644
--- a/library/std/src/sys/pal/xous/mod.rs
+++ b/library/std/src/sys/pal/xous/mod.rs
@@ -1,5 +1,7 @@
 #![forbid(unsafe_op_in_unsafe_fn)]
 
+use crate::os::xous::ffi::exit;
+
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;
@@ -9,3 +11,7 @@ pub mod time;
 #[path = "../unsupported/common.rs"]
 mod common;
 pub use common::*;
+
+pub fn abort_internal() -> ! {
+    exit(101);
+}
diff --git a/library/std/src/sys/pal/xous/os.rs b/library/std/src/sys/pal/xous/os.rs
index 2230dabe096..d612a27d2bd 100644
--- a/library/std/src/sys/pal/xous/os.rs
+++ b/library/std/src/sys/pal/xous/os.rs
@@ -62,14 +62,6 @@ mod c_compat {
         }
         exit(unsafe { main() });
     }
-
-    // This function is needed by the panic runtime. The symbol is named in
-    // pre-link args for the target specification, so keep that in sync.
-    #[unsafe(no_mangle)]
-    // NB. used by both libunwind and libpanic_abort
-    pub extern "C" fn __rust_abort() -> ! {
-        exit(101);
-    }
 }
 
 pub fn errno() -> i32 {