Rollup merge of rust-lang#138988 - madsmtm:internal-weak-macro-syntax, r=ibraheemdev

Change the syntax of the internal `weak!` macro

Change the syntax to include parameter names and a trailing semicolon.

Motivation:
- Mirror the `syscall!` macro.
- Allow rustfmt to format it (when wrapped in parentheses, and when not inside `cfg_if!`).
- For better documentation (having the parameter names available in the source code is a bit nicer).
- Allow a future improvement to this macro where we can sometimes use the symbol directly when it's statically known to be available (and thus need the parameter names to be available), see rust-lang#136868.

r? libs

Author: matthiaskrgr

Diff for: std/src/sys/fs/unix.rs

@@ -155,15 +155,15 @@ cfg_has_statx! {{
         enum STATX_STATE{ Unknown = 0, Present, Unavailable }
         static STATX_SAVED_STATE: AtomicU8 = AtomicU8::new(STATX_STATE::Unknown as u8);
 
-        syscall! {
+        syscall!(
             fn statx(
                 fd: c_int,
                 pathname: *const c_char,
                 flags: c_int,
                 mask: libc::c_uint,
-                statxbuf: *mut libc::statx
-            ) -> c_int
-        }
+                statxbuf: *mut libc::statx,
+            ) -> c_int;
+        );
 
         let statx_availability = STATX_SAVED_STATE.load(Ordering::Relaxed);
         if statx_availability == STATX_STATE::Unavailable as u8 {
@@ -1540,7 +1540,9 @@ impl File {
                 let times = [to_timespec(times.accessed)?, to_timespec(times.modified)?];
                 // futimens requires Android API level 19
                 cvt(unsafe {
-                    weak!(fn futimens(c_int, *const libc::timespec) -> c_int);
+                    weak!(
+                        fn futimens(fd: c_int, times: *const libc::timespec) -> c_int;
+                    );
                     match futimens.get() {
                         Some(futimens) => futimens(self.as_raw_fd(), times.as_ptr()),
                         None => return Err(io::const_error!(
@@ -1556,7 +1558,9 @@ impl File {
                     use crate::sys::{time::__timespec64, weak::weak};
 
                     // Added in glibc 2.34
-                    weak!(fn __futimens64(libc::c_int, *const __timespec64) -> libc::c_int);
+                    weak!(
+                        fn __futimens64(fd: c_int, times: *const __timespec64) -> c_int;
+                    );
 
                     if let Some(futimens64) = __futimens64.get() {
                         let to_timespec = |time: Option<SystemTime>| time.map(|time| time.t.to_timespec64())

Diff for: std/src/sys/pal/unix/fd.rs

@@ -232,14 +232,14 @@ impl FileDesc {
     // implementation if `preadv` is not available.
     #[cfg(all(target_os = "android", target_pointer_width = "64"))]
     pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
-        super::weak::syscall! {
+        super::weak::syscall!(
             fn preadv(
                 fd: libc::c_int,
                 iovec: *const libc::iovec,
                 n_iovec: libc::c_int,
-                offset: off64_t
-            ) -> isize
-        }
+                offset: off64_t,
+            ) -> isize;
+        );
 
         let ret = cvt(unsafe {
             preadv(
@@ -257,7 +257,14 @@ impl FileDesc {
     // and its metadata from LLVM IR.
     #[no_sanitize(cfi)]
     pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
-        super::weak::weak!(fn preadv64(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
+        super::weak::weak!(
+            fn preadv64(
+                fd: libc::c_int,
+                iovec: *const libc::iovec,
+                n_iovec: libc::c_int,
+                offset: off64_t,
+            ) -> isize;
+        );
 
         match preadv64.get() {
             Some(preadv) => {
@@ -286,7 +293,14 @@ impl FileDesc {
     // use "weak" linking.
     #[cfg(target_vendor = "apple")]
     pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
-        super::weak::weak!(fn preadv(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
+        super::weak::weak!(
+            fn preadv(
+                fd: libc::c_int,
+                iovec: *const libc::iovec,
+                n_iovec: libc::c_int,
+                offset: off64_t,
+            ) -> isize;
+        );
 
         match preadv.get() {
             Some(preadv) => {
@@ -428,14 +442,14 @@ impl FileDesc {
     // implementation if `pwritev` is not available.
     #[cfg(all(target_os = "android", target_pointer_width = "64"))]
     pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
-        super::weak::syscall! {
+        super::weak::syscall!(
             fn pwritev(
                 fd: libc::c_int,
                 iovec: *const libc::iovec,
                 n_iovec: libc::c_int,
-                offset: off64_t
-            ) -> isize
-        }
+                offset: off64_t,
+            ) -> isize;
+        );
 
         let ret = cvt(unsafe {
             pwritev(
@@ -450,7 +464,14 @@ impl FileDesc {
 
     #[cfg(all(target_os = "android", target_pointer_width = "32"))]
     pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
-        super::weak::weak!(fn pwritev64(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
+        super::weak::weak!(
+            fn pwritev64(
+                fd: libc::c_int,
+                iovec: *const libc::iovec,
+                n_iovec: libc::c_int,
+                offset: off64_t,
+            ) -> isize;
+        );
 
         match pwritev64.get() {
             Some(pwritev) => {
@@ -479,7 +500,14 @@ impl FileDesc {
     // use "weak" linking.
     #[cfg(target_vendor = "apple")]
     pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
-        super::weak::weak!(fn pwritev(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
+        super::weak::weak!(
+            fn pwritev(
+                fd: libc::c_int,
+                iovec: *const libc::iovec,
+                n_iovec: libc::c_int,
+                offset: off64_t,
+            ) -> isize;
+        );
 
         match pwritev.get() {
             Some(pwritev) => {

Diff for: std/src/sys/pal/unix/kernel_copy.rs

@@ -604,16 +604,16 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) ->
         _ => true,
     };
 
-    syscall! {
+    syscall!(
         fn copy_file_range(
             fd_in: libc::c_int,
             off_in: *mut libc::loff_t,
             fd_out: libc::c_int,
             off_out: *mut libc::loff_t,
             len: libc::size_t,
-            flags: libc::c_uint
-        ) -> libc::ssize_t
-    }
+            flags: libc::c_uint,
+        ) -> libc::ssize_t;
+    );
 
     fn probe_copy_file_range_support() -> u8 {
         // In some cases, we cannot determine availability from the first
@@ -727,16 +727,16 @@ fn sendfile_splice(mode: SpliceMode, reader: RawFd, writer: RawFd, len: u64) ->
     // Android builds use feature level 14, but the libc wrapper for splice is
     // gated on feature level 21+, so we have to invoke the syscall directly.
     #[cfg(target_os = "android")]
-    syscall! {
+    syscall!(
         fn splice(
             srcfd: libc::c_int,
             src_offset: *const i64,
             dstfd: libc::c_int,
             dst_offset: *const i64,
             len: libc::size_t,
-            flags: libc::c_int
-        ) -> libc::ssize_t
-    }
+            flags: libc::c_int,
+        ) -> libc::ssize_t;
+    );
 
     #[cfg(target_os = "linux")]
     use libc::splice;

Diff for: std/src/sys/pal/unix/stack_overflow.rs

@@ -424,18 +424,32 @@ mod imp {
 
         let pages = PAGES.get_or_init(|| {
             use crate::sys::weak::dlsym;
-            dlsym!(fn sysctlbyname(*const libc::c_char, *mut libc::c_void, *mut libc::size_t, *const libc::c_void, libc::size_t) -> libc::c_int);
+            dlsym!(
+                fn sysctlbyname(
+                    name: *const libc::c_char,
+                    oldp: *mut libc::c_void,
+                    oldlenp: *mut libc::size_t,
+                    newp: *const libc::c_void,
+                    newlen: libc::size_t,
+                ) -> libc::c_int;
+            );
             let mut guard: usize = 0;
             let mut size = size_of_val(&guard);
             let oid = c"security.bsd.stack_guard_page";
             match sysctlbyname.get() {
-                Some(fcn) if unsafe {
-                    fcn(oid.as_ptr(),
-                        (&raw mut guard).cast(),
-                        &raw mut size,
-                        ptr::null_mut(),
-                        0) == 0
-                } => guard,
+                Some(fcn)
+                    if unsafe {
+                        fcn(
+                            oid.as_ptr(),
+                            (&raw mut guard).cast(),
+                            &raw mut size,
+                            ptr::null_mut(),
+                            0,
+                        ) == 0
+                    } =>
+                {
+                    guard
+                }
                 _ => 1,
             }
         });

Diff for: std/src/sys/pal/unix/thread.rs

@@ -193,11 +193,12 @@ impl Thread {
     // and its metadata from LLVM IR.
     #[no_sanitize(cfi)]
     pub fn set_name(name: &CStr) {
-        weak! {
+        weak!(
             fn pthread_setname_np(
-                libc::pthread_t, *const libc::c_char
-            ) -> libc::c_int
-        }
+                thread: libc::pthread_t,
+                name: *const libc::c_char,
+            ) -> libc::c_int;
+        );
 
         if let Some(f) = pthread_setname_np.get() {
             #[cfg(target_os = "nto")]
@@ -762,7 +763,9 @@ unsafe fn min_stack_size(attr: *const libc::pthread_attr_t) -> usize {
     // We use dlsym to avoid an ELF version dependency on GLIBC_PRIVATE. (#23628)
     // We shouldn't really be using such an internal symbol, but there's currently
     // no other way to account for the TLS size.
-    dlsym!(fn __pthread_get_minstack(*const libc::pthread_attr_t) -> libc::size_t);
+    dlsym!(
+        fn __pthread_get_minstack(attr: *const libc::pthread_attr_t) -> libc::size_t;
+    );
 
     match __pthread_get_minstack.get() {
         None => libc::PTHREAD_STACK_MIN,

Diff for: std/src/sys/pal/unix/time.rs

@@ -123,7 +123,12 @@ impl Timespec {
 
             // __clock_gettime64 was added to 32-bit arches in glibc 2.34,
             // and it handles both vDSO calls and ENOSYS fallbacks itself.
-            weak!(fn __clock_gettime64(libc::clockid_t, *mut __timespec64) -> libc::c_int);
+            weak!(
+                fn __clock_gettime64(
+                    clockid: libc::clockid_t,
+                    tp: *mut __timespec64,
+                ) -> libc::c_int;
+            );
 
             if let Some(clock_gettime64) = __clock_gettime64.get() {
                 let mut t = MaybeUninit::uninit();

Diff for: std/src/sys/pal/unix/weak.rs

@@ -29,7 +29,7 @@ use crate::{mem, ptr};
 // We can use true weak linkage on ELF targets.
 #[cfg(all(unix, not(target_vendor = "apple")))]
 pub(crate) macro weak {
-    (fn $name:ident($($t:ty),*) -> $ret:ty) => (
+    (fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;) => (
         let ref $name: ExternWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
             unsafe extern "C" {
                 #[linkage = "extern_weak"]
@@ -62,10 +62,16 @@ impl<F: Copy> ExternWeak<F> {
 }
 
 pub(crate) macro dlsym {
-    (fn $name:ident($($t:ty),*) -> $ret:ty) => (
-         dlsym!(fn $name($($t),*) -> $ret, stringify!($name));
+    (fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;) => (
+         dlsym!(
+            #[link_name = stringify!($name)]
+            fn $name($($param : $t),*) -> $ret;
+        );
     ),
-    (fn $name:ident($($t:ty),*) -> $ret:ty, $sym:expr) => (
+    (
+        #[link_name = $sym:expr]
+        fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;
+    ) => (
         static DLSYM: DlsymWeak<unsafe extern "C" fn($($t),*) -> $ret> =
             DlsymWeak::new(concat!($sym, '\0'));
         let $name = &DLSYM;
@@ -143,15 +149,15 @@ unsafe fn fetch(name: &str) -> *mut libc::c_void {
 
 #[cfg(not(any(target_os = "linux", target_os = "android")))]
 pub(crate) macro syscall {
-    (fn $name:ident($($arg_name:ident: $t:ty),*) -> $ret:ty) => (
+    (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 $name($($arg_name: $t),*) -> $ret {
-            weak! { fn $name($($t),*) -> $ret }
+        unsafe fn $name($($param: $t),*) -> $ret {
+            weak!(fn $name($($param: $t),*) -> $ret;);
 
             if let Some(fun) = $name.get() {
-                fun($($arg_name),*)
+                fun($($param),*)
             } else {
                 super::os::set_errno(libc::ENOSYS);
                 -1
@@ -162,26 +168,28 @@ pub(crate) macro syscall {
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub(crate) macro syscall {
-    (fn $name:ident($($arg_name:ident: $t:ty),*) -> $ret:ty) => (
-        unsafe fn $name($($arg_name:$t),*) -> $ret {
-            weak! { fn $name($($t),*) -> $ret }
+    (
+        fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;
+    ) => (
+        unsafe fn $name($($param: $t),*) -> $ret {
+            weak!(fn $name($($param: $t),*) -> $ret;);
 
             // Use a weak symbol from libc when possible, allowing `LD_PRELOAD`
             // interposition, but if it's not found just use a raw syscall.
             if let Some(fun) = $name.get() {
-                fun($($arg_name),*)
+                fun($($param),*)
             } else {
-                libc::syscall(libc::${concat(SYS_, $name)}, $($arg_name),*) as $ret
+                libc::syscall(libc::${concat(SYS_, $name)}, $($param),*) as $ret
             }
         }
     )
 }
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub(crate) macro raw_syscall {
-    (fn $name:ident($($arg_name:ident: $t:ty),*) -> $ret:ty) => (
-        unsafe fn $name($($arg_name:$t),*) -> $ret {
-            libc::syscall(libc::${concat(SYS_, $name)}, $($arg_name),*) as $ret
+    (fn $name:ident($($param:ident : $t:ty),* $(,)?) -> $ret:ty;) => (
+        unsafe fn $name($($param: $t),*) -> $ret {
+            libc::syscall(libc::${concat(SYS_, $name)}, $($param),*) as $ret
         }
     )
 }