Rename the no_std feature to core.

See
https://github.com/yurydelendik/wasmparser.rs/pull/49#issuecomment-375436225
for more details.

README.rst

@@ -62,14 +62,14 @@ Building with `no_std`
 
 To build cretonne without libstd, disable the `std` feature on `lib/cretonne`,
 `lib/frontend`, `lib/native`, and `lib/wasm`, which is otherwise enabled by
-default, and enable the `no_std` feature.
+default, and enable the `core` feature.
 
 For example, to build `cretonne`:
 
 .. code-block:: sh
 
     cd lib/cretonne
-    cargo build --no-default-features --features no_std
+    cargo build --no-default-features --features core
 
 Or, when using `cretonne` as a dependency (in Cargo.toml):
 
@@ -78,23 +78,23 @@ Or, when using `cretonne` as a dependency (in Cargo.toml):
     [dependency.cretonne]
     ...
     default-features = false
-    features = ["no_std"]
+    features = ["core"]
 
-`no_std` is currently "best effort". We won't try to break it, and we'll
+`no_std` support is currently "best effort". We won't try to break it, and
-accept patches fixing problems, however we don't expect all developers to
+we'll accept patches fixing problems, however we don't expect all developers to
-build and test with `no_std` when submitting patches. Accordingly, the
+build and test `no_std` when submitting patches. Accordingly, the
 `./test-all.sh` script does not test `no_std`.
 
 There is a separate `./test-no_std.sh` script that tests the `no_std`
-feature in packages which support it.
+support in packages which support it.
 
 It's important to note that cretonne still needs liballoc to compile.
 Thus, whatever environment is used must implement an allocator.
 
-Also, to allow the use of HashMaps in `no_std` mode, an external crate
+Also, to allow the use of HashMaps with `no_std`, an external crate called
-called `hashmap_core` is pulled in (only in `no_std` builds). This
+`hashmap_core` is pulled in (via the `core` feature). This is mostly the same
-is mostly the same as `std::collections::HashMap`, except that it doesn't
+as `std::collections::HashMap`, except that it doesn't have DOS protection.
-have DOS protection. Just something to think about.
+Just something to think about.
 
 Building the documentation
 --------------------------

cranelift/test-no_std.sh

@@ -21,8 +21,8 @@ for LIB in $LIBS
 do
     banner "Rust unit tests in $LIB"
     cd "lib/$LIB"
-    cargo test --no-default-features --features no_std
+    cargo test --no-default-features --features core
-    cargo test --features no_std
+    cargo test --features core
     cd "$topdir"
 done
 

lib/cretonne/Cargo.toml

@@ -26,9 +26,9 @@ version = "0.1.1"
 optional = true
 
 [features]
-# The "std" feature enables use of libstd. The "no_std" feature enables use
+# The "std" feature enables use of libstd. The "core" feature enables use
 # of some minimal std-like replacement libraries. At least one of these two
 # features to be enabled.
 default = ["std"]
 std = []
-no_std = ["hashmap_core"]
+core = ["hashmap_core"]

lib/cretonne/src/dbg.rs

@@ -8,23 +8,23 @@
 ///
 /// The output will appear in files named `cretonne.dbg.*`, where the suffix is named after the
 /// thread doing the logging.
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::cell::RefCell;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::env;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::ffi::OsStr;
 use std::fmt;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fs::File;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::io::{self, Write};
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::sync::atomic;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::thread;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 static STATE: atomic::AtomicIsize = atomic::ATOMIC_ISIZE_INIT;
 
 /// Is debug tracing enabled?
@@ -33,7 +33,7 @@ static STATE: atomic::AtomicIsize = atomic::ATOMIC_ISIZE_INIT;
 /// other than `0`.
 ///
 /// This inline function turns into a constant `false` when debug assertions are disabled.
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 #[inline]
 pub fn enabled() -> bool {
     if cfg!(debug_assertions) {
@@ -47,14 +47,14 @@ pub fn enabled() -> bool {
 }
 
 /// Does nothing
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 #[inline]
 pub fn enabled() -> bool {
     false
 }
 
 /// Initialize `STATE` from the environment variable.
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 fn initialize() -> bool {
     let enable = match env::var_os("CRETONNE_DBG") {
         Some(s) => s != OsStr::new("0"),
@@ -70,7 +70,7 @@ fn initialize() -> bool {
     enable
 }
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 thread_local! {
     static WRITER : RefCell<io::BufWriter<File>> = RefCell::new(open_file());
 }
@@ -78,7 +78,7 @@ thread_local! {
 /// Write a line with the given format arguments.
 ///
 /// This is for use by the `dbg!` macro.
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 pub fn writeln_with_format_args(args: fmt::Arguments) -> io::Result<()> {
     WRITER.with(|rc| {
         let mut w = rc.borrow_mut();
@@ -88,7 +88,7 @@ pub fn writeln_with_format_args(args: fmt::Arguments) -> io::Result<()> {
 }
 
 /// Open the tracing file for the current thread.
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 fn open_file() -> io::BufWriter<File> {
     let curthread = thread::current();
     let tmpstr;
@@ -116,7 +116,7 @@ macro_rules! dbg {
         if $crate::dbg::enabled() {
             // Drop the error result so we don't get compiler errors for ignoring it.
             // What are you going to do, log the error?
-            #[cfg(not(feature = "no_std"))]
+            #[cfg(feature = "std")]
             $crate::dbg::writeln_with_format_args(format_args!($($arg)+)).ok();
         }
     }

lib/cretonne/src/lib.rs

@@ -4,13 +4,13 @@
         trivial_numeric_casts,
         unused_extern_crates)]
 
-// Turns on alloc feature if no_std
+// Turns on no_std and alloc features if std is not available.
 #![cfg_attr(not(feature = "std"), no_std)]
 #![cfg_attr(not(feature = "std"), feature(alloc))]
 
-// Include the `hashmap_core` crate if no_std
+// Include the `hashmap_core` crate if std is not available.
 #[allow(unused_extern_crates)]
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate hashmap_core;
 #[cfg(not(feature = "std"))]
 #[macro_use]
@@ -66,7 +66,7 @@ mod topo_order;
 mod unreachable_code;
 mod write;
 
-/// This replaces `std` in builds with no_std.
+/// This replaces `std` in builds with `core`.
 #[cfg(not(feature = "std"))]
 mod std {
     pub use core::*;

lib/cretonne/src/timing.rs

@@ -93,7 +93,7 @@ impl fmt::Display for Pass {
 /// This whole module can be gated on a `cfg` feature to provide a dummy implementation for
 /// performance-sensitive builds or restricted environments. The dummy implementation must provide
 /// `TimingToken` and `PassTimes` types and `take_current`, `add_to_current`, and `start_pass` funcs
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 mod details {
     use super::{Pass, NUM_PASSES, DESCRIPTIONS};
     use std::cell::{Cell, RefCell};
@@ -216,7 +216,7 @@ mod details {
 }
 
 /// Dummy `debug` implementation
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 mod details {
     use super::Pass;
     /// Dummy `TimingToken`

lib/cretonne/src/verifier/mod.rs

@@ -1125,9 +1125,9 @@ mod tests {
                 Ok(_) => { panic!("Expected an error!") },
                 Err(Error { message, .. } ) => {
                     if !message.contains($msg) {
-                       #[cfg(not(feature = "no_std"))]
+                       #[cfg(feature = "std")]
                        panic!(format!("'{}' did not contain the substring '{}'", message, $msg));
-                       #[cfg(feature = "no_std")]
+                       #[cfg(not(feature = "std"))]
                        panic!("error message did not contain the expected substring");
                     }
                 }

lib/frontend/Cargo.toml

@@ -17,4 +17,4 @@ cretonne = { path = "../cretonne", version = "0.3.4", default-features = false }
 [features]
 default = ["std"]
 std = ["cretonne/std"]
-no_std = ["cretonne/no_std"]
+core = ["cretonne/core"]

lib/frontend/src/ssa.rs

@@ -1026,9 +1026,9 @@ mod tests {
         match verify_function(&func, &flags) {
             Ok(()) => {}
             Err(err) => {
-                #[cfg(not(feature = "no_std"))]
+                #[cfg(feature = "std")]
                 panic!(err.message);
-                #[cfg(feature = "no_std")]
+                #[cfg(not(feature = "std"))]
                 panic!("function failed to verify");
             }
         }
@@ -1205,9 +1205,9 @@ mod tests {
         match verify_function(&func, &flags) {
             Ok(()) => {}
             Err(err) => {
-                #[cfg(not(feature = "no_std"))]
+                #[cfg(feature = "std")]
                 panic!(err.message);
-                #[cfg(feature = "no_std")]
+                #[cfg(not(feature = "std"))]
                 panic!("function failed to verify");
             }
         }
@@ -1256,9 +1256,9 @@ mod tests {
         match verify_function(&func, &flags) {
             Ok(()) => {}
             Err(err) => {
-                #[cfg(not(feature = "no_std"))]
+                #[cfg(feature = "std")]
                 panic!(err.message);
-                #[cfg(feature = "no_std")]
+                #[cfg(not(feature = "std"))]
                 panic!("function failed to verify");
             }
         }

lib/native/Cargo.toml

@@ -19,4 +19,4 @@ raw-cpuid = "3.0.0"
 [features]
 default = ["std"]
 std = ["cretonne/std"]
-no_std = ["cretonne/no_std"]
+core = ["cretonne/core"]

lib/wasm/Cargo.toml

@@ -26,4 +26,4 @@ tempdir = "0.3.5"
 [features]
 default = ["std"]
 std = ["cretonne/std", "cretonne-frontend/std"]
-no_std = ["hashmap_core", "cretonne/no_std", "cretonne-frontend/no_std"]
+core = ["hashmap_core", "cretonne/core", "cretonne-frontend/core"]

lib/wasm/src/lib.rs

@@ -21,7 +21,7 @@
 extern crate alloc;
 
 #[allow(unused_extern_crates)]
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate hashmap_core;
 
 extern crate wasmparser;