runtime: dirty hacks to remove allocations in ksupport.

artiq/runtime.rs/Cargo.toml

@@ -13,7 +13,7 @@ crate-type = ["staticlib"]
 path = "src/lib.rs"
 
 [dependencies]
-std_artiq = { path = "libstd_artiq" }
+std_artiq = { path = "libstd_artiq", features = ["alloc"] }
 lwip = { path = "liblwip", default-features = false }
 fringe = { version = "= 1.1.0", default-features = false, features = ["alloc"] }
 log = { version = "0.3", default-features = false, features = [] }

artiq/runtime.rs/libksupport/lib.rs

@@ -127,7 +127,7 @@ extern fn send_async_rpc(service: u32, tag: *const u8, data: *const *const ()) {
         };
         proto::write_u32(&mut slice, length as u32)
     }).unwrap_or_else(|err| {
-        assert!(err.kind() == std::io::ErrorKind::UnexpectedEof);
+        assert!(err.kind() == std::io::ErrorKind::WriteZero);
 
         send(&RpcSend {
             async:   true,

artiq/runtime.rs/liblwip/Cargo.toml

@@ -9,7 +9,7 @@ path = "lib.rs"
 
 [dependencies]
 lwip-sys = { path = "../liblwip-sys" }
-std_artiq = { path = "../libstd_artiq" }
+std_artiq = { path = "../libstd_artiq", features = ["alloc"] }
 
 [features]
 default = ["preemption"]

artiq/runtime.rs/libstd_artiq/Cargo.toml

@@ -9,3 +9,6 @@ path = "lib.rs"
 
 [dependencies]
 alloc_artiq = { path = "../liballoc_artiq" }
+
+[features]
+alloc = []

artiq/runtime.rs/libstd_artiq/io/error.rs

@@ -8,7 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
- use alloc::boxed::Box;
+#[cfg(feature="alloc")] use alloc::boxed::Box;
+#[cfg(not(feature="alloc"))] use ::FakeBox as Box;
 use core::convert::Into;
 use core::fmt;
 use core::marker::{Send, Sync};
@@ -62,13 +63,19 @@ pub struct Error {
 enum Repr {
     Os(i32),
 
+    #[cfg(feature="alloc")]
     Custom(Box<Custom>),
+    #[cfg(not(feature="alloc"))]
+    Custom(Custom),
 }
 
 #[derive(Debug)]
 struct Custom {
     kind: ErrorKind,
+    #[cfg(feature="alloc")]
     error: Box<error::Error+Send+Sync>,
+    #[cfg(not(feature="alloc"))]
+    error: &'static str
 }
 
 /// A list specifying general categories of I/O error.
@@ -162,12 +169,21 @@ impl Error {
     /// // errors can also be created from other errors
     /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
     /// ```
+    #[cfg(feature="alloc")]
     pub fn new<E>(kind: ErrorKind, error: E) -> Error
         where E: Into<Box<error::Error+Send+Sync>>
     {
         Self::_new(kind, error.into())
     }
 
+    #[cfg(not(feature="alloc"))]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<&'static str>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    #[cfg(feature="alloc")]
     fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
         Error {
             repr: Repr::Custom(Box::new(Custom {
@@ -177,6 +193,16 @@ impl Error {
         }
     }
 
+    #[cfg(not(feature="alloc"))]
+    fn _new(kind: ErrorKind, error: &'static str) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
     /// Creates a new instance of an `Error` from a particular OS error code.
     pub fn from_raw_os_error(code: i32) -> Error {
         Error { repr: Repr::Os(code) }
@@ -198,6 +224,7 @@ impl Error {
     ///
     /// If this `Error` was constructed via `new` then this function will
     /// return `Some`, otherwise it will return `None`.
+    #[cfg(feature="alloc")]
     pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
         match self.repr {
             Repr::Os(..) => None,
@@ -210,6 +237,7 @@ impl Error {
     ///
     /// If this `Error` was constructed via `new` then this function will
     /// return `Some`, otherwise it will return `None`.
+    #[cfg(feature="alloc")]
     pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
         match self.repr {
             Repr::Os(..) => None,
@@ -221,6 +249,7 @@ impl Error {
     ///
     /// If this `Error` was constructed via `new` then this function will
     /// return `Some`, otherwise it will return `None`.
+    #[cfg(feature="alloc")]
     pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
         match self.repr {
             Repr::Os(..) => None,
@@ -282,14 +311,24 @@ impl error::Error for Error {
                 ErrorKind::UnexpectedEof => "unexpected end of file",
                 ErrorKind::__Nonexhaustive => unreachable!()
             },
-            Repr::Custom(ref c) => c.error.description(),
+            Repr::Custom(ref c) => {
+                #[cfg(feature="alloc")]
+                { c.error.description() }
+                #[cfg(not(feature="alloc"))]
+                { c.error }
+            },
         }
     }
 
     fn cause(&self) -> Option<&error::Error> {
         match self.repr {
             Repr::Os(..) => None,
-            Repr::Custom(ref c) => c.error.cause(),
+            Repr::Custom(ref _c) => {
+                #[cfg(feature="alloc")]
+                { _c.error.cause() }
+                #[cfg(not(feature="alloc"))]
+                { None }
+            }
         }
     }
 }

artiq/runtime.rs/libstd_artiq/lib.rs

@@ -1,6 +1,7 @@
 #![feature(lang_items, asm, alloc, collections, libc, needs_panic_runtime,
            question_mark, unicode, reflect_marker, raw, int_error_internals,
-           try_from, try_borrow, macro_reexport, allow_internal_unstable)]
+           try_from, try_borrow, macro_reexport, allow_internal_unstable,
+           stmt_expr_attributes)]
 #![no_std]
 #![needs_panic_runtime]
 
@@ -31,3 +32,13 @@ pub mod prelude {
 
 pub mod error;
 pub mod io;
+
+// Provide Box::new wrapper
+#[cfg(not(feature="alloc"))]
+struct FakeBox<T>(core::marker::PhantomData<T>);
+#[cfg(not(feature="alloc"))]
+impl<T> FakeBox<T> {
+    fn new(val: T) -> T {
+        val
+    }
+}

artiq/runtime.rs/src/proto.rs

@@ -67,7 +67,8 @@ pub fn write_bytes(writer: &mut Write, value: &[u8]) -> io::Result<()> {
 
 pub fn read_string(reader: &mut Read) -> io::Result<String> {
     let bytes = try!(read_bytes(reader));
-    String::from_utf8(bytes).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
+    String::from_utf8(bytes)
+           .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "invalid UTF-8"))
 }
 
 pub fn write_string(writer: &mut Write, value: &str) -> io::Result<()> {