cfi: Remove #[no_sanitize(cfi)] for extern weak functions

Previously (rust-lang#115200,
rust-lang#138002), we
added `#[no_sanitize(cfi)]` to all code paths that call to a weakly
linked function.

In rust-lang#138349 we fixed the root cause
for this issue, which means we can now remove the corresponding
attributes.

Author: 1c3t3a

library/std/src/sys/fd/unix.rs

@@ -257,9 +257,6 @@ impl FileDesc {
     }
 
     #[cfg(all(target_os = "android", target_pointer_width = "32"))]
-    // FIXME(#115199): Rust currently omits weak function definitions
-    // and its metadata from LLVM IR.
-    #[no_sanitize(cfi)]
     pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
         weak!(
             fn preadv64(

library/std/src/sys/fs/unix.rs

@@ -1463,20 +1463,6 @@ impl File {
         Ok(())
     }
 
-    // FIXME(#115199): Rust currently omits weak function definitions
-    // and its metadata from LLVM IR.
-    #[cfg_attr(
-        any(
-            target_os = "android",
-            all(
-                target_os = "linux",
-                target_env = "gnu",
-                target_pointer_width = "32",
-                not(target_arch = "riscv32")
-            )
-        ),
-        no_sanitize(cfi)
-    )]
     pub fn set_times(&self, times: FileTimes) -> io::Result<()> {
         #[cfg(not(any(
             target_os = "redox",

library/std/src/sys/pal/unix/thread.rs

@@ -189,9 +189,6 @@ impl Thread {
     }
 
     #[cfg(any(target_os = "solaris", target_os = "illumos", target_os = "nto"))]
-    // FIXME(#115199): Rust currently omits weak function definitions
-    // and its metadata from LLVM IR.
-    #[no_sanitize(cfi)]
     pub fn set_name(name: &CStr) {
         weak!(
             fn pthread_setname_np(

library/std/src/sys/pal/unix/time.rs

@@ -96,17 +96,6 @@ impl Timespec {
         }
     }
 
-    // FIXME(#115199): Rust currently omits weak function definitions
-    // and its metadata from LLVM IR.
-    #[cfg_attr(
-        all(
-            target_os = "linux",
-            target_env = "gnu",
-            target_pointer_width = "32",
-            not(target_arch = "riscv32")
-        ),
-        no_sanitize(cfi)
-    )]
     pub fn now(clock: libc::clockid_t) -> Timespec {
         use crate::mem::MaybeUninit;
         use crate::sys::cvt;

library/std/src/sys/pal/unix/weak.rs

@@ -155,9 +155,6 @@ unsafe fn fetch(name: &str) -> *mut libc::c_void {
 #[cfg(not(any(target_os = "linux", target_os = "android")))]
 pub(crate) macro syscall {
     (fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;) => (
-        // FIXME(#115199): Rust currently omits weak function definitions
-        // and its metadata from LLVM IR.
-        #[no_sanitize(cfi)]
         unsafe fn $name($($param: $t),*) -> $ret {
             weak!(fn $name($($param: $t),*) -> $ret;);
 

library/std/src/sys/process/unix/unix.rs

@@ -434,9 +434,6 @@ impl Command {
         target_os = "nto",
         target_vendor = "apple",
     ))]
-    // FIXME(#115199): Rust currently omits weak function definitions
-    // and its metadata from LLVM IR.
-    #[cfg_attr(target_os = "linux", no_sanitize(cfi))]
     fn posix_spawn(
         &mut self,
         stdio: &ChildPipes,

library/std/src/sys/thread_local/destructors/linux_like.rs

@@ -12,9 +12,6 @@
 
 use crate::mem::transmute;
 
-// FIXME: The Rust compiler currently omits weakly function definitions (i.e.,
-// __cxa_thread_atexit_impl) and its metadata from LLVM IR.
-#[no_sanitize(cfi, kcfi)]
 pub unsafe fn register(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) {
     /// This is necessary because the __cxa_thread_atexit_impl implementation
     /// std links to by default may be a C or C++ implementation that was not