Auto merge of rust-lang#115228 - saethlin:is-interrupted, r=thomcc

Add a new helper to avoid calling io::Error::kind

On `cfg(unix)`, `Error::kind` emits an enormous jump table that LLVM seems unable to optimize out. I don't really understand why, but see for yourself: https://godbolt.org/z/17hY496KG

This change lets us check for `ErrorKind::Interrupted` without going through a big match. I've checked the codegen locally, and it has the desired effect on the codegen for `BufReader::read_exact`.

Author: bors

library/std/src/fs.rs

@@ -745,14 +745,17 @@ fn buffer_capacity_required(mut file: &File) -> Option<usize> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Read for &File {
+    #[inline]
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
 
+    #[inline]
     fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
         self.inner.read_vectored(bufs)
     }
 
+    #[inline]
     fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
         self.inner.read_buf(cursor)
     }

library/std/src/io/error.rs

@@ -916,6 +916,16 @@ impl Error {
             ErrorData::SimpleMessage(m) => m.kind,
         }
     }
+
+    #[inline]
+    pub(crate) fn is_interrupted(&self) -> bool {
+        match self.repr.data() {
+            ErrorData::Os(code) => sys::is_interrupted(code),
+            ErrorData::Custom(c) => c.kind == ErrorKind::Interrupted,
+            ErrorData::Simple(kind) => kind == ErrorKind::Interrupted,
+            ErrorData::SimpleMessage(m) => m.kind == ErrorKind::Interrupted,
+        }
+    }
 }
 
 impl fmt::Debug for Repr {

library/std/src/io/mod.rs

@@ -390,7 +390,7 @@ pub(crate) fn default_read_to_end<R: Read + ?Sized>(
         let mut cursor = read_buf.unfilled();
         match r.read_buf(cursor.reborrow()) {
             Ok(()) => {}
-            Err(e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) if e.is_interrupted() => continue,
             Err(e) => return Err(e),
         }
 
@@ -421,7 +421,7 @@ pub(crate) fn default_read_to_end<R: Read + ?Sized>(
                         buf.extend_from_slice(&probe[..n]);
                         break;
                     }
-                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(ref e) if e.is_interrupted() => continue,
                     Err(e) => return Err(e),
                 }
             }
@@ -470,7 +470,7 @@ pub(crate) fn default_read_exact<R: Read + ?Sized>(this: &mut R, mut buf: &mut [
                 let tmp = buf;
                 buf = &mut tmp[n..];
             }
-            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(ref e) if e.is_interrupted() => {}
             Err(e) => return Err(e),
         }
     }
@@ -860,7 +860,7 @@ pub trait Read {
             let prev_written = cursor.written();
             match self.read_buf(cursor.reborrow()) {
                 Ok(()) => {}
-                Err(e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) if e.is_interrupted() => continue,
                 Err(e) => return Err(e),
             }
 
@@ -1579,7 +1579,7 @@ pub trait Write {
                     ));
                 }
                 Ok(n) => buf = &buf[n..],
-                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(ref e) if e.is_interrupted() => {}
                 Err(e) => return Err(e),
             }
         }
@@ -1943,7 +1943,7 @@ fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>) -> R
         let (done, used) = {
             let available = match r.fill_buf() {
                 Ok(n) => n,
-                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(ref e) if e.is_interrupted() => continue,
                 Err(e) => return Err(e),
             };
             match memchr::memchr(delim, available) {
@@ -2734,7 +2734,7 @@ impl<R: Read> Iterator for Bytes<R> {
             return match self.inner.read(slice::from_mut(&mut byte)) {
                 Ok(0) => None,
                 Ok(..) => Some(Ok(byte)),
-                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(ref e) if e.is_interrupted() => continue,
                 Err(e) => Some(Err(e)),
             };
         }

library/std/src/sys/itron/error.rs

@@ -79,6 +79,11 @@ pub fn error_name(er: abi::ER) -> Option<&'static str> {
     }
 }
 
+#[inline]
+pub fn is_interrupted(er: abi::ER) -> bool {
+    er == abi::E_RLWAI
+}
+
 pub fn decode_error_kind(er: abi::ER) -> ErrorKind {
     match er {
         // Success

library/std/src/sys/sgx/mod.rs

@@ -86,6 +86,12 @@ pub fn sgx_ineffective<T>(v: T) -> crate::io::Result<T> {
     }
 }
 
+#[inline]
+pub fn is_interrupted(code: i32) -> bool {
+    use fortanix_sgx_abi::Error;
+    code == Error::Interrupted as _
+}
+
 pub fn decode_error_kind(code: i32) -> ErrorKind {
     use fortanix_sgx_abi::Error;
 

library/std/src/sys/solid/error.rs

@@ -31,6 +31,11 @@ pub fn error_name(er: abi::ER) -> Option<&'static str> {
     }
 }
 
+#[inline]
+fn is_interrupted(er: abi::ER) -> bool {
+    false
+}
+
 pub fn decode_error_kind(er: abi::ER) -> ErrorKind {
     match er {
         // Success

library/std/src/sys/solid/mod.rs

@@ -72,6 +72,11 @@ pub fn unsupported_err() -> crate::io::Error {
     )
 }
 
+#[inline]
+pub fn is_interrupted(code: i32) -> bool {
+    error::is_interrupted(code)
+}
+
 pub fn decode_error_kind(code: i32) -> crate::io::ErrorKind {
     error::decode_error_kind(code)
 }

library/std/src/sys/solid/net.rs

@@ -181,6 +181,12 @@ pub(super) fn error_name(er: abi::ER) -> Option<&'static str> {
     unsafe { CStr::from_ptr(netc::strerror(er)) }.to_str().ok()
 }
 
+#[inline]
+pub fn is_interrupted(er: abi::ER) -> bool {
+    let errno = netc::SOLID_NET_ERR_BASE - er;
+    errno as libc::c_int == libc::EINTR
+}
+
 pub(super) fn decode_error_kind(er: abi::ER) -> ErrorKind {
     let errno = netc::SOLID_NET_ERR_BASE - er;
     match errno as libc::c_int {

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

@@ -240,6 +240,11 @@ pub use crate::sys::android::signal;
 #[cfg(not(target_os = "android"))]
 pub use libc::signal;
 
+#[inline]
+pub(crate) fn is_interrupted(errno: i32) -> bool {
+    errno == libc::EINTR
+}
+
 pub fn decode_error_kind(errno: i32) -> ErrorKind {
     use ErrorKind::*;
     match errno as libc::c_int {

library/std/src/sys/unsupported/common.rs

@@ -23,6 +23,10 @@ pub fn unsupported_err() -> std_io::Error {
     )
 }
 
+pub fn is_interrupted(_code: i32) -> bool {
+    false
+}
+
 pub fn decode_error_kind(_code: i32) -> crate::io::ErrorKind {
     crate::io::ErrorKind::Uncategorized
 }

library/std/src/sys/wasi/mod.rs

@@ -76,6 +76,11 @@ cfg_if::cfg_if! {
 mod common;
 pub use common::*;
 
+#[inline]
+pub fn is_interrupted(errno: i32) -> bool {
+    errno == wasi::ERRNO_INTR.raw().into()
+}
+
 pub fn decode_error_kind(errno: i32) -> std_io::ErrorKind {
     use std_io::ErrorKind::*;
     if errno > u16::MAX as i32 || errno < 0 {

library/std/src/sys/windows/mod.rs

@@ -60,6 +60,11 @@ pub unsafe fn cleanup() {
     net::cleanup();
 }
 
+#[inline]
+pub fn is_interrupted(_errno: i32) -> bool {
+    false
+}
+
 pub fn decode_error_kind(errno: i32) -> ErrorKind {
     use ErrorKind::*;