Switch from error_core to failure.

README.rst

@@ -92,10 +92,6 @@ called `hashmap_core` is pulled in (only in `no_std` builds). This
 is mostly the same as `std::collections::HashMap`, except that it doesn't
 have DOS protection. Just something to think about.
 
-Lastly, to support `std::error`, which isn't is `std` or `alloc` for
-an inexplicable reason, the `error_core` crate is also used in `no_std` builds.
-You might need it, as well, when interfacing with `CtonError`.
-
 Building the documentation
 --------------------------
 

lib/cretonne/Cargo.toml

@@ -17,19 +17,17 @@ name = "cretonne"
 # Please don't add any unless they are essential to the task of creating binary
 # machine code. Integration tests that need external dependencies can be
 # accomodated in `tests`.
+failure = { version = "0.1.1", default-features = false, features = ["derive"] }
+failure_derive = { version = "0.1.1", default-features = false }
 
 [dependencies.hashmap_core]
 version = "0.1.1"
 optional = true
 
-[dependencies.error_core]
-version = "0.1.0"
-optional = true
-
 [features]
 # The "std" feature enables use of libstd. The "no_std" 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", "error_core"]
+no_std = ["hashmap_core"]

lib/cretonne/src/lib.rs

@@ -8,11 +8,12 @@
 // Include the `hashmap_core` crate if no_std
 #[cfg(feature = "no_std")]
 extern crate hashmap_core;
-#[cfg(feature = "no_std")]
-extern crate error_core;
 #[cfg(not(feature = "std"))]
 #[macro_use]
 extern crate alloc;
+extern crate failure;
+#[macro_use]
+extern crate failure_derive;
 
 pub use context::Context;
 pub use legalizer::legalize_function;
@@ -69,7 +70,4 @@ mod std {
         pub use hashmap_core::map as hash_map;
         pub use alloc::BTreeSet;
     }
-    pub mod error {
-        pub use error_core::Error;
-    }
 }

lib/cretonne/src/result.rs

@@ -1,25 +1,28 @@
 //! Result and error types representing the outcome of compiling a function.
 
 use verifier;
-use std::error::Error as StdError;
-use std::fmt;
 
 /// A compilation error.
 ///
 /// When Cretonne fails to compile a function, it will return one of these error codes.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Fail, Debug, PartialEq, Eq)]
 pub enum CtonError {
     /// The input is invalid.
     ///
     /// This error code is used by a WebAssembly translator when it encounters invalid WebAssembly
     /// code. This should never happen for validated WebAssembly code.
+    #[fail(display = "Invalid input code")]
     InvalidInput,
 
     /// An IL verifier error.
     ///
     /// This always represents a bug, either in the code that generated IL for Cretonne, or a bug
     /// in Cretonne itself.
-    Verifier(verifier::Error),
+    #[fail(display = "Verifier error: {}", _0)]
+    Verifier(
+        #[cause]
+        verifier::Error
+    ),
 
     /// An implementation limit was exceeded.
     ///
@@ -27,48 +30,20 @@ pub enum CtonError {
     /// limits][limits] that cause compilation to fail when they are exceeded.
     ///
     /// [limits]: http://cretonne.readthedocs.io/en/latest/langref.html#implementation-limits
+    #[fail(display = "Implementation limit exceeded")]
     ImplLimitExceeded,
 
     /// The code size for the function is too large.
     ///
     /// Different target ISAs may impose a limit on the size of a compiled function. If that limit
     /// is exceeded, compilation fails.
+    #[fail(display = "Code for function is too large")]
     CodeTooLarge,
 }
 
 /// A Cretonne compilation result.
 pub type CtonResult = Result<(), CtonError>;
 
-impl fmt::Display for CtonError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            CtonError::Verifier(ref e) => write!(f, "Verifier error: {}", e),
-            CtonError::InvalidInput |
-            CtonError::ImplLimitExceeded |
-            CtonError::CodeTooLarge => f.write_str(self.description()),
-        }
-    }
-}
-
-impl StdError for CtonError {
-    fn description(&self) -> &str {
-        match *self {
-            CtonError::InvalidInput => "Invalid input code",
-            CtonError::Verifier(ref e) => &e.message,
-            CtonError::ImplLimitExceeded => "Implementation limit exceeded",
-            CtonError::CodeTooLarge => "Code for function is too large",
-        }
-    }
-    fn cause(&self) -> Option<&StdError> {
-        match *self {
-            CtonError::Verifier(ref e) => Some(e),
-            CtonError::InvalidInput |
-            CtonError::ImplLimitExceeded |
-            CtonError::CodeTooLarge => None,
-        }
-    }
-}
-
 impl From<verifier::Error> for CtonError {
     fn from(e: verifier::Error) -> CtonError {
         CtonError::Verifier(e)

lib/cretonne/src/verifier/mod.rs

@@ -70,7 +70,6 @@ use self::flags::verify_flags;
 use settings::{Flags, FlagsOrIsa};
 use std::cmp::Ordering;
 use std::collections::BTreeSet;
-use std::error as std_error;
 use std::fmt::{self, Display, Formatter, Write};
 use std::result;
 use std::vec::Vec;
@@ -104,7 +103,7 @@ mod liveness;
 mod locations;
 
 /// A verifier error.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Fail, Debug, PartialEq, Eq)]
 pub struct Error {
     /// The entity causing the verifier error.
     pub location: AnyEntity,
@@ -118,12 +117,6 @@ impl Display for Error {
     }
 }
 
-impl std_error::Error for Error {
-    fn description(&self) -> &str {
-        &self.message
-    }
-}
-
 /// Verifier result.
 pub type Result = result::Result<(), Error>;
 

lib/filecheck/Cargo.toml

@@ -12,3 +12,5 @@ name = "filecheck"
 
 [dependencies]
 regex = "0.2.6"
+failure = "0.1.1"
+failure_derive = "0.1.1"

lib/filecheck/src/error.rs

@@ -1,21 +1,21 @@
 use std::result;
 use std::convert::From;
-use std::error::Error as StdError;
-use std::fmt;
 use regex;
 
 /// A result from the filecheck library.
 pub type Result<T> = result::Result<T, Error>;
 
 /// A filecheck error.
-#[derive(Debug)]
+#[derive(Fail, Debug)]
 pub enum Error {
     /// A syntax error in a check line.
+    #[fail(display = "{}", _0)]
     Syntax(String),
     /// A check refers to an undefined variable.
     ///
     /// The pattern contains `$foo` where the `foo` variable has not yet been defined.
     /// Use `$$` to match a literal dollar sign.
+    #[fail(display = "{}", _0)]
     UndefVariable(String),
     /// A pattern contains a back-reference to a variable that was defined in the same pattern.
     ///
@@ -26,40 +26,19 @@ pub enum Error {
     /// check: Hello $(world=[^ ]*)
     /// sameln: $world
     /// ```
+    #[fail(display = "{}", _0)]
     Backref(String),
     /// A pattern contains multiple definitions of the same variable.
+    #[fail(display = "{}", _0)]
     DuplicateDef(String),
     /// An error in a regular expression.
     ///
     /// Use `cause()` to get the underlying `Regex` library error.
-    Regex(regex::Error),
-}
-
-impl StdError for Error {
-    fn description(&self) -> &str {
-        use Error::*;
-        match *self {
-            Syntax(ref s) |
-            UndefVariable(ref s) |
-            Backref(ref s) |
-            DuplicateDef(ref s) => s,
-            Regex(ref err) => err.description(),
-        }
-    }
-
-    fn cause(&self) -> Option<&StdError> {
-        use Error::*;
-        match *self {
-            Regex(ref err) => Some(err),
-            _ => None,
-        }
-    }
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{}", self.description())
-    }
+    #[fail(display = "{}", _0)]
+    Regex(
+        #[cause]
+        regex::Error
+    ),
 }
 
 impl From<regex::Error> for Error {

lib/filecheck/src/lib.rs

@@ -243,6 +243,9 @@ pub use variable::{VariableMap, Value, NO_VARIABLES};
 pub use checker::{Checker, CheckerBuilder};
 
 extern crate regex;
+extern crate failure;
+#[macro_use]
+extern crate failure_derive;
 
 mod error;
 mod variable;

lib/wasm/Cargo.toml

@@ -19,14 +19,10 @@ cretonne-frontend = { path = "../frontend", version = "0.1.0", default_features
 version = "0.1.1"
 optional = true
 
-[dependencies.error_core]
-version = "0.1.0"
-optional = true
-
 [dev-dependencies]
 tempdir = "0.3.5"
 
 [features]
 default = ["std"]
 std = ["cretonne/std", "cretonne-frontend/std"]
-no_std = ["hashmap_core", "error_core", "cretonne/no_std", "cretonne-frontend/no_std"]
+no_std = ["hashmap_core", "cretonne/no_std", "cretonne-frontend/no_std"]

lib/wasm/src/environ/dummy.rs

@@ -9,7 +9,6 @@ use cretonne::ir::types::*;
 use cretonne::cursor::FuncCursor;
 use cretonne::settings;
 use wasmparser;
-use std::error::Error;
 use std::vec::Vec;
 use std::string::String;
 
@@ -387,7 +386,7 @@ impl<'data> ModuleEnvironment<'data> for DummyEnvironment {
             let reader = wasmparser::BinaryReader::new(body_bytes);
             self.trans
                 .translate_from_reader(reader, &mut func, &mut func_environ)
-                .map_err(|e| String::from(e.description()))?;
+                .map_err(|e| format!("{}", e))?;
             func
         };
         self.func_bytecode_sizes.push(body_bytes.len());

lib/wasm/src/lib.rs

@@ -20,8 +20,6 @@ extern crate alloc;
 
 #[cfg(feature = "no_std")]
 extern crate hashmap_core;
-#[cfg(feature = "no_std")]
-extern crate error_core;
 
 extern crate wasmparser;
 extern crate cton_frontend;
@@ -50,7 +48,4 @@ mod std {
     pub mod collections {
         pub use hashmap_core::{HashMap, map as hash_map};
     }
-    pub mod error {
-        pub use error_core::Error;
-    }
 }