Merge #3

3: add an opt-out "const-fn" Cargo feature r=japaric a=japaric

with the feature disabled this crate compiles on stable

Co-authored-by: Jorge Aparicio <[email protected]>

Author: bors[bot]

.travis.yml

@@ -0,0 +1,36 @@
+language: rust
+
+matrix:
+  include:
+    - env: TARGET=x86_64-unknown-linux-gnu
+    # - env: TARGET=thumbv6m-none-eabi
+    # - env: TARGET=thumbv7m-none-eabi
+    - env: TARGET=thumbv6m-none-eabi
+      rust: nightly
+    - env: TARGET=thumbv7m-none-eabi
+      rust: nightly
+
+before_install: set -e
+
+install:
+  - bash ci/install.sh
+
+script:
+  - bash ci/script.sh
+
+after_script: set +e
+
+cache: cargo
+
+before_cache:
+  # Travis can't cache files that are not readable by "others"
+  - chmod -R a+r $HOME/.cargo
+
+branches:
+  only:
+    - staging
+    - trying
+
+notifications:
+  email:
+    on_success: never

Cargo.toml

@@ -9,4 +9,6 @@ name = "bare-metal"
 repository = "https://github.com/japaric/bare-metal"
 version = "0.1.1"
 
-[dependencies]
+[features]
+default = ["const-fn"]
+const-fn = []

bors.toml

@@ -0,0 +1,3 @@
+status = [
+  "continuous-integration/travis-ci/push",
+]

ci/install.sh

@@ -0,0 +1,9 @@
+set -euxo pipefail
+
+main() {
+    if [ $TARGET != x86_64-unknown-linux-gnu ]; then
+        rustup target add $TARGET
+    fi
+}
+
+main

ci/script.sh

@@ -0,0 +1,11 @@
+set -euxo pipefail
+
+main() {
+    cargo check --target $TARGET --no-default-features
+
+    if [ $TRAVIS_RUST_VERSION = nightly ]; then
+        cargo check --target $TARGET
+    fi
+}
+
+main

src/lib.rs

@@ -2,7 +2,7 @@
 
 #![deny(missing_docs)]
 #![deny(warnings)]
-#![feature(const_fn,const_unsafe_cell_new)]
+#![cfg_attr(feature = "const-fn", feature(const_fn, const_unsafe_cell_new))]
 #![no_std]
 
 use core::cell::UnsafeCell;
@@ -20,8 +20,21 @@ impl<T> Peripheral<T> {
     /// Creates a new peripheral
     ///
     /// `address` is the base address of the register block
+    #[cfg(feature = "const-fn")]
     pub const unsafe fn new(address: usize) -> Self {
-        Peripheral { address: address as *mut T }
+        Peripheral {
+            address: address as *mut T,
+        }
+    }
+
+    /// Creates a new peripheral
+    ///
+    /// `address` is the base address of the register block
+    #[cfg(not(feature = "const-fn"))]
+    pub unsafe fn new(address: usize) -> Self {
+        Peripheral {
+            address: address as *mut T,
+        }
     }
 
     /// Borrows the peripheral for the duration of a critical section
@@ -59,8 +72,19 @@ pub struct Mutex<T> {
 
 impl<T> Mutex<T> {
     /// Creates a new mutex
+    #[cfg(feature = "const-fn")]
     pub const fn new(value: T) -> Self {
-        Mutex { inner: UnsafeCell::new(value) }
+        Mutex {
+            inner: UnsafeCell::new(value),
+        }
+    }
+
+    /// Creates a new mutex
+    #[cfg(not(feature = "const-fn"))]
+    pub fn new(value: T) -> Self {
+        Mutex {
+            inner: UnsafeCell::new(value),
+        }
     }
 }