std: Add `{read,write}_vectored` for more types

This commit implements the `{read,write}_vectored` methods on more types
in the standard library, namely:

* `std::fs::File`
* `std::process::ChildStd{in,out,err}`
* `std::io::Std{in,out,err}`
* `std::io::Std{in,out,err}Lock`
* `std::io::Std{in,out,err}Raw`

Where supported the OS implementations hook up to native support,
otherwise it falls back to the already-defaulted implementation.

19 files changed, 247 insertions, 37 deletions

diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index 14ff4d72f87..dea198d8c91 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -9,7 +9,7 @@
 
 use crate::fmt;
 use crate::ffi::OsString;
-use crate::io::{self, SeekFrom, Seek, Read, Initializer, Write};
+use crate::io::{self, SeekFrom, Seek, Read, Initializer, Write, IoVec, IoVecMut};
 use crate::path::{Path, PathBuf};
 use crate::sys::fs as fs_imp;
 use crate::sys_common::{AsInnerMut, FromInner, AsInner, IntoInner};
@@ -615,6 +615,10 @@ impl Read for File {
         self.inner.read(buf)
     }
 
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.inner.read_vectored(bufs)
+    }
+
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
@@ -625,6 +629,11 @@ impl Write for File {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.write(buf)
     }
+
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.inner.write_vectored(bufs)
+    }
+
     fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -639,6 +648,10 @@ impl Read for &File {
         self.inner.read(buf)
     }
 
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.inner.read_vectored(bufs)
+    }
+
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
@@ -649,6 +662,11 @@ impl Write for &File {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.write(buf)
     }
+
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.inner.write_vectored(bufs)
+    }
+
     fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 0bbff5769ab..1848ddeab65 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -5,7 +5,7 @@ use crate::io::prelude::*;
 use crate::cell::RefCell;
 use crate::fmt;
 use crate::io::lazy::Lazy;
-use crate::io::{self, Initializer, BufReader, LineWriter};
+use crate::io::{self, Initializer, BufReader, LineWriter, IoVec, IoVecMut};
 use crate::sync::{Arc, Mutex, MutexGuard};
 use crate::sys::stdio;
 use crate::sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
@@ -75,6 +75,10 @@ fn stderr_raw() -> io::Result<StderrRaw> { stdio::Stderr::new().map(StderrRaw) }
 impl Read for StdinRaw {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { self.0.read(buf) }
 
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.0.read_vectored(bufs)
+    }
+
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
@@ -82,10 +86,20 @@ impl Read for StdinRaw {
 }
 impl Write for StdoutRaw {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.0.write(buf) }
+
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.0.write_vectored(bufs)
+    }
+
     fn flush(&mut self) -> io::Result<()> { self.0.flush() }
 }
 impl Write for StderrRaw {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.0.write(buf) }
+
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.0.write_vectored(bufs)
+    }
+
     fn flush(&mut self) -> io::Result<()> { self.0.flush() }
 }
 
@@ -102,6 +116,14 @@ impl<W: io::Write> io::Write for Maybe<W> {
         }
     }
 
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        let total = bufs.iter().map(|b| b.len()).sum();
+        match self {
+            Maybe::Real(w) => handle_ebadf(w.write_vectored(bufs), total),
+            Maybe::Fake => Ok(total),
+        }
+    }
+
     fn flush(&mut self) -> io::Result<()> {
         match *self {
             Maybe::Real(ref mut w) => handle_ebadf(w.flush(), ()),
@@ -117,6 +139,13 @@ impl<R: io::Read> io::Read for Maybe<R> {
             Maybe::Fake => Ok(0)
         }
     }
+
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self {
+            Maybe::Real(r) => handle_ebadf(r.read_vectored(bufs), 0),
+            Maybe::Fake => Ok(0)
+        }
+    }
 }
 
 fn handle_ebadf<T>(r: io::Result<T>, default: T) -> io::Result<T> {
@@ -305,6 +334,9 @@ impl Read for Stdin {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.lock().read(buf)
     }
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.lock().read_vectored(bufs)
+    }
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
@@ -325,6 +357,11 @@ impl Read for StdinLock<'_> {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
+
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.inner.read_vectored(bufs)
+    }
+
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
@@ -483,6 +520,9 @@ impl Write for Stdout {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.lock().write(buf)
     }
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.lock().write_vectored(bufs)
+    }
     fn flush(&mut self) -> io::Result<()> {
         self.lock().flush()
     }
@@ -498,6 +538,9 @@ impl Write for StdoutLock<'_> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.borrow_mut().write(buf)
     }
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.inner.borrow_mut().write_vectored(bufs)
+    }
     fn flush(&mut self) -> io::Result<()> {
         self.inner.borrow_mut().flush()
     }
@@ -636,6 +679,9 @@ impl Write for Stderr {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.lock().write(buf)
     }
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.lock().write_vectored(bufs)
+    }
     fn flush(&mut self) -> io::Result<()> {
         self.lock().flush()
     }
@@ -651,6 +697,9 @@ impl Write for StderrLock<'_> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.borrow_mut().write(buf)
     }
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.inner.borrow_mut().write_vectored(bufs)
+    }
     fn flush(&mut self) -> io::Result<()> {
         self.inner.borrow_mut().flush()
     }
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index e0c9b7cad86..ef5626700e8 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -111,7 +111,7 @@ use crate::io::prelude::*;
 use crate::ffi::OsStr;
 use crate::fmt;
 use crate::fs;
-use crate::io::{self, Initializer};
+use crate::io::{self, Initializer, IoVec, IoVecMut};
 use crate::path::Path;
 use crate::str;
 use crate::sys::pipe::{read2, AnonPipe};
@@ -225,6 +225,10 @@ impl Write for ChildStdin {
         self.inner.write(buf)
     }
 
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.inner.write_vectored(bufs)
+    }
+
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }
@@ -271,6 +275,11 @@ impl Read for ChildStdout {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
+
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.inner.read_vectored(bufs)
+    }
+
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
@@ -318,6 +327,11 @@ impl Read for ChildStderr {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
+
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.inner.read_vectored(bufs)
+    }
+
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
         Initializer::nop()
diff --git a/src/libstd/sys/cloudabi/shims/fs.rs b/src/libstd/sys/cloudabi/shims/fs.rs
index ee045b8e515..abd7f0fd3ee 100644
--- a/src/libstd/sys/cloudabi/shims/fs.rs
+++ b/src/libstd/sys/cloudabi/shims/fs.rs
@@ -1,7 +1,7 @@
 use crate::ffi::OsString;
 use crate::fmt;
 use crate::hash::{Hash, Hasher};
-use crate::io::{self, SeekFrom};
+use crate::io::{self, SeekFrom, IoVec, IoVecMut};
 use crate::path::{Path, PathBuf};
 use crate::sys::time::SystemTime;
 use crate::sys::{unsupported, Void};
@@ -198,10 +198,18 @@ impl File {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn flush(&self) -> io::Result<()> {
         match self.0 {}
     }
diff --git a/src/libstd/sys/cloudabi/shims/pipe.rs b/src/libstd/sys/cloudabi/shims/pipe.rs
index f3debb95047..804d3e001ac 100644
--- a/src/libstd/sys/cloudabi/shims/pipe.rs
+++ b/src/libstd/sys/cloudabi/shims/pipe.rs
@@ -1,4 +1,4 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::sys::Void;
 
 pub struct AnonPipe(Void);
@@ -8,10 +8,18 @@ impl AnonPipe {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn diverge(&self) -> ! {
         match self.0 {}
     }
diff --git a/src/libstd/sys/redox/fs.rs b/src/libstd/sys/redox/fs.rs
index ebefbc94210..c86c6000eae 100644
--- a/src/libstd/sys/redox/fs.rs
+++ b/src/libstd/sys/redox/fs.rs
@@ -2,7 +2,7 @@ use crate::os::unix::prelude::*;
 
 use crate::ffi::{OsString, OsStr};
 use crate::fmt;
-use crate::io::{self, Error, SeekFrom};
+use crate::io::{self, Error, SeekFrom, IoVec, IoVecMut};
 use crate::path::{Path, PathBuf};
 use crate::sync::Arc;
 use crate::sys::fd::FileDesc;
@@ -278,10 +278,18 @@ impl File {
         self.0.read(buf)
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        crate::io::default_read_vectored(|buf| self.read(buf), bufs)
+    }
+
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
         self.0.write(buf)
     }
 
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        crate::io::default_write_vectored(|buf| self.write(buf), bufs)
+    }
+
     pub fn flush(&self) -> io::Result<()> { Ok(()) }
 
     pub fn seek(&self, pos: SeekFrom) -> io::Result<u64> {
diff --git a/src/libstd/sys/redox/pipe.rs b/src/libstd/sys/redox/pipe.rs
index 911ba9c3f65..b926968f7b3 100644
--- a/src/libstd/sys/redox/pipe.rs
+++ b/src/libstd/sys/redox/pipe.rs
@@ -1,4 +1,4 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::sys::{cvt, syscall};
 use crate::sys::fd::FileDesc;
 
@@ -24,10 +24,18 @@ impl AnonPipe {
         self.0.read(buf)
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        crate::io::default_read_vectored(|buf| self.read(buf), bufs)
+    }
+
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
         self.0.write(buf)
     }
 
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        crate::io::default_write_vectored(|buf| self.write(buf), bufs)
+    }
+
     pub fn fd(&self) -> &FileDesc { &self.0 }
     pub fn into_fd(self) -> FileDesc { self.0 }
 }
diff --git a/src/libstd/sys/sgx/fs.rs b/src/libstd/sys/sgx/fs.rs
index 68c8e9356a8..c3c898eb23e 100644
--- a/src/libstd/sys/sgx/fs.rs
+++ b/src/libstd/sys/sgx/fs.rs
@@ -1,7 +1,7 @@
 use crate::ffi::OsString;
 use crate::fmt;
 use crate::hash::{Hash, Hasher};
-use crate::io::{self, SeekFrom};
+use crate::io::{self, SeekFrom, IoVec, IoVecMut};
 use crate::path::{Path, PathBuf};
 use crate::sys::time::SystemTime;
 use crate::sys::{unsupported, Void};
@@ -200,10 +200,18 @@ impl File {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn flush(&self) -> io::Result<()> {
         match self.0 {}
     }
diff --git a/src/libstd/sys/sgx/pipe.rs b/src/libstd/sys/sgx/pipe.rs
index 2582b993b60..804d3e001ac 100644
--- a/src/libstd/sys/sgx/pipe.rs
+++ b/src/libstd/sys/sgx/pipe.rs
@@ -1,4 +1,4 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::sys::Void;
 
 pub struct AnonPipe(Void);
@@ -8,18 +8,23 @@ impl AnonPipe {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn diverge(&self) -> ! {
         match self.0 {}
     }
 }
 
-pub fn read2(p1: AnonPipe,
-             _v1: &mut Vec<u8>,
-             _p2: AnonPipe,
-             _v2: &mut Vec<u8>) -> io::Result<()> {
+pub fn read2(p1: AnonPipe, _v1: &mut Vec<u8>, _p2: AnonPipe, _v2: &mut Vec<u8>) -> io::Result<()> {
     match p1.0 {}
 }
diff --git a/src/libstd/sys/unix/fs.rs b/src/libstd/sys/unix/fs.rs
index dc3dcb5817c..a14db108c34 100644
--- a/src/libstd/sys/unix/fs.rs
+++ b/src/libstd/sys/unix/fs.rs
@@ -2,7 +2,7 @@ use crate::os::unix::prelude::*;
 
 use crate::ffi::{CString, CStr, OsString, OsStr};
 use crate::fmt;
-use crate::io::{self, Error, ErrorKind, SeekFrom};
+use crate::io::{self, Error, ErrorKind, SeekFrom, IoVec, IoVecMut};
 use crate::mem;
 use crate::path::{Path, PathBuf};
 use crate::ptr;
@@ -560,6 +560,10 @@ impl File {
         self.0.read(buf)
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.0.read_vectored(bufs)
+    }
+
     pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
         self.0.read_at(buf, offset)
     }
@@ -568,6 +572,10 @@ impl File {
         self.0.write(buf)
     }
 
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.0.write_vectored(bufs)
+    }
+
     pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
         self.0.write_at(buf, offset)
     }
diff --git a/src/libstd/sys/unix/pipe.rs b/src/libstd/sys/unix/pipe.rs
index bc3c026adab..a7792d42af9 100644
--- a/src/libstd/sys/unix/pipe.rs
+++ b/src/libstd/sys/unix/pipe.rs
@@ -1,4 +1,4 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::mem;
 use crate::sync::atomic::{AtomicBool, Ordering};
 use crate::sys::fd::FileDesc;
@@ -60,10 +60,18 @@ impl AnonPipe {
         self.0.read(buf)
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.0.read_vectored(bufs)
+    }
+
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
         self.0.write(buf)
     }
 
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.0.write_vectored(bufs)
+    }
+
     pub fn fd(&self) -> &FileDesc { &self.0 }
     pub fn into_fd(self) -> FileDesc { self.0 }
 }
diff --git a/src/libstd/sys/unix/stdio.rs b/src/libstd/sys/unix/stdio.rs
index 35f163bbdb1..bc2986f624e 100644
--- a/src/libstd/sys/unix/stdio.rs
+++ b/src/libstd/sys/unix/stdio.rs
@@ -1,5 +1,6 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::sys::fd::FileDesc;
+use crate::mem::ManuallyDrop;
 
 pub struct Stdin(());
 pub struct Stdout(());
@@ -11,10 +12,11 @@ impl Stdin {
 
 impl io::Read for Stdin {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let fd = FileDesc::new(libc::STDIN_FILENO);
-        let ret = fd.read(buf);
-        fd.into_raw(); // do not close this FD
-        ret
+        ManuallyDrop::new(FileDesc::new(libc::STDIN_FILENO)).read(buf)
+    }
+
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        ManuallyDrop::new(FileDesc::new(libc::STDIN_FILENO)).read_vectored(bufs)
     }
 }
 
@@ -24,10 +26,11 @@ impl Stdout {
 
 impl io::Write for Stdout {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        let fd = FileDesc::new(libc::STDOUT_FILENO);
-        let ret = fd.write(buf);
-        fd.into_raw(); // do not close this FD
-        ret
+        ManuallyDrop::new(FileDesc::new(libc::STDOUT_FILENO)).write(buf)
+    }
+
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        ManuallyDrop::new(FileDesc::new(libc::STDOUT_FILENO)).write_vectored(bufs)
     }
 
     fn flush(&mut self) -> io::Result<()> {
@@ -41,10 +44,11 @@ impl Stderr {
 
 impl io::Write for Stderr {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        let fd = FileDesc::new(libc::STDERR_FILENO);
-        let ret = fd.write(buf);
-        fd.into_raw(); // do not close this FD
-        ret
+        ManuallyDrop::new(FileDesc::new(libc::STDERR_FILENO)).write(buf)
+    }
+
+    fn write_vectored(&mut self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        ManuallyDrop::new(FileDesc::new(libc::STDERR_FILENO)).write_vectored(bufs)
     }
 
     fn flush(&mut self) -> io::Result<()> {
diff --git a/src/libstd/sys/wasi/pipe.rs b/src/libstd/sys/wasi/pipe.rs
index 2582b993b60..aa6bf8076f6 100644
--- a/src/libstd/sys/wasi/pipe.rs
+++ b/src/libstd/sys/wasi/pipe.rs
@@ -1,4 +1,4 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::sys::Void;
 
 pub struct AnonPipe(Void);
@@ -8,10 +8,18 @@ impl AnonPipe {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn diverge(&self) -> ! {
         match self.0 {}
     }
diff --git a/src/libstd/sys/wasi/stdio.rs b/src/libstd/sys/wasi/stdio.rs
index 19294788666..bdad4084891 100644
--- a/src/libstd/sys/wasi/stdio.rs
+++ b/src/libstd/sys/wasi/stdio.rs
@@ -13,8 +13,12 @@ impl Stdin {
     }
 
     pub fn read(&self, data: &mut [u8]) -> io::Result<usize> {
+        self.read_vectored(&mut [IoVecMut::new(data)])
+    }
+
+    pub fn read_vectored(&self, data: &mut [IoVecMut<'_>]) -> io::Result<usize> {
         ManuallyDrop::new(unsafe { WasiFd::from_raw(libc::STDIN_FILENO as u32) })
-            .read(&mut [IoVecMut::new(data)])
+            .read(data)
     }
 }
 
@@ -24,8 +28,12 @@ impl Stdout {
     }
 
     pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        self.write_vectored(&[IoVec::new(data)])
+    }
+
+    pub fn write_vectored(&self, data: &[IoVec<'_>]) -> io::Result<usize> {
         ManuallyDrop::new(unsafe { WasiFd::from_raw(libc::STDOUT_FILENO as u32) })
-            .write(&[IoVec::new(data)])
+            .write(data)
     }
 
     pub fn flush(&self) -> io::Result<()> {
@@ -39,8 +47,12 @@ impl Stderr {
     }
 
     pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        self.write_vectored(&[IoVec::new(data)])
+    }
+
+    pub fn write_vectored(&self, data: &[IoVec<'_>]) -> io::Result<usize> {
         ManuallyDrop::new(unsafe { WasiFd::from_raw(libc::STDERR_FILENO as u32) })
-            .write(&[IoVec::new(data)])
+            .write(data)
     }
 
     pub fn flush(&self) -> io::Result<()> {
diff --git a/src/libstd/sys/wasm/fs.rs b/src/libstd/sys/wasm/fs.rs
index 68c8e9356a8..c3c898eb23e 100644
--- a/src/libstd/sys/wasm/fs.rs
+++ b/src/libstd/sys/wasm/fs.rs
@@ -1,7 +1,7 @@
 use crate::ffi::OsString;
 use crate::fmt;
 use crate::hash::{Hash, Hasher};
-use crate::io::{self, SeekFrom};
+use crate::io::{self, SeekFrom, IoVec, IoVecMut};
 use crate::path::{Path, PathBuf};
 use crate::sys::time::SystemTime;
 use crate::sys::{unsupported, Void};
@@ -200,10 +200,18 @@ impl File {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn flush(&self) -> io::Result<()> {
         match self.0 {}
     }
diff --git a/src/libstd/sys/wasm/pipe.rs b/src/libstd/sys/wasm/pipe.rs
index 2582b993b60..aa6bf8076f6 100644
--- a/src/libstd/sys/wasm/pipe.rs
+++ b/src/libstd/sys/wasm/pipe.rs
@@ -1,4 +1,4 @@
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::sys::Void;
 
 pub struct AnonPipe(Void);
@@ -8,10 +8,18 @@ impl AnonPipe {
         match self.0 {}
     }
 
+    pub fn read_vectored(&self, _bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
 
+    pub fn write_vectored(&self, _bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        match self.0 {}
+    }
+
     pub fn diverge(&self) -> ! {
         match self.0 {}
     }
diff --git a/src/libstd/sys/windows/fs.rs b/src/libstd/sys/windows/fs.rs
index 4ebbb0707f7..1d8e47a4793 100644
--- a/src/libstd/sys/windows/fs.rs
+++ b/src/libstd/sys/windows/fs.rs
@@ -2,7 +2,7 @@ use crate::os::windows::prelude::*;
 
 use crate::ffi::OsString;
 use crate::fmt;
-use crate::io::{self, Error, SeekFrom};
+use crate::io::{self, Error, SeekFrom, IoVec, IoVecMut};
 use crate::mem;
 use crate::path::{Path, PathBuf};
 use crate::ptr;
@@ -314,6 +314,10 @@ impl File {
         self.handle.read(buf)
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.handle.read_vectored(bufs)
+    }
+
     pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
         self.handle.read_at(buf, offset)
     }
@@ -322,6 +326,10 @@ impl File {
         self.handle.write(buf)
     }
 
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.handle.write_vectored(bufs)
+    }
+
     pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
         self.handle.write_at(buf, offset)
     }
diff --git a/src/libstd/sys/windows/handle.rs b/src/libstd/sys/windows/handle.rs
index 02549088c87..c3fa6c4e0bd 100644
--- a/src/libstd/sys/windows/handle.rs
+++ b/src/libstd/sys/windows/handle.rs
@@ -1,7 +1,7 @@
 #![unstable(issue = "0", feature = "windows_handle")]
 
 use crate::cmp;
-use crate::io::{self, ErrorKind, Read};
+use crate::io::{self, ErrorKind, Read, IoVec, IoVecMut};
 use crate::mem;
 use crate::ops::Deref;
 use crate::ptr;
@@ -89,6 +89,10 @@ impl RawHandle {
         }
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        crate::io::default_read_vectored(|buf| self.read(buf), bufs)
+    }
+
     pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
         let mut read = 0;
         let len = cmp::min(buf.len(), <c::DWORD>::max_value() as usize) as c::DWORD;
@@ -169,6 +173,10 @@ impl RawHandle {
         Ok(amt as usize)
     }
 
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        crate::io::default_write_vectored(|buf| self.write(buf), bufs)
+    }
+
     pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
         let mut written = 0;
         let len = cmp::min(buf.len(), <c::DWORD>::max_value() as usize) as c::DWORD;
@@ -199,4 +207,8 @@ impl<'a> Read for &'a RawHandle {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         (**self).read(buf)
     }
+
+    fn read_vectored(&mut self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        (**self).read_vectored(bufs)
+    }
 }
diff --git a/src/libstd/sys/windows/pipe.rs b/src/libstd/sys/windows/pipe.rs
index b38727830f3..6613d3a0567 100644
--- a/src/libstd/sys/windows/pipe.rs
+++ b/src/libstd/sys/windows/pipe.rs
@@ -1,7 +1,7 @@
 use crate::os::windows::prelude::*;
 
 use crate::ffi::OsStr;
-use crate::io;
+use crate::io::{self, IoVec, IoVecMut};
 use crate::mem;
 use crate::path::Path;
 use crate::ptr;
@@ -166,9 +166,17 @@ impl AnonPipe {
         self.inner.read(buf)
     }
 
+    pub fn read_vectored(&self, bufs: &mut [IoVecMut<'_>]) -> io::Result<usize> {
+        self.inner.read_vectored(bufs)
+    }
+
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
         self.inner.write(buf)
     }
+
+    pub fn write_vectored(&self, bufs: &[IoVec<'_>]) -> io::Result<usize> {
+        self.inner.write_vectored(bufs)
+    }
 }
 
 pub fn read2(p1: AnonPipe,