moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

cranelift/codegen/src/result.rs

@@ -0,0 +1,42 @@
+//! Result and error types representing the outcome of compiling a function.
+
+use crate::verifier::VerifierErrors;
+use failure_derive::Fail;
+
+/// A compilation error.
+///
+/// When Cranelift fails to compile a function, it will return one of these error codes.
+#[derive(Fail, Debug, PartialEq, Eq)]
+pub enum CodegenError {
+    /// A list of IR verifier errors.
+    ///
+    /// This always represents a bug, either in the code that generated IR for Cranelift, or a bug
+    /// in Cranelift itself.
+    #[fail(display = "Verifier errors:\n{}", _0)]
+    Verifier(#[cause] VerifierErrors),
+
+    /// An implementation limit was exceeded.
+    ///
+    /// Cranelift can compile very large and complicated functions, but the [implementation has
+    /// limits][limits] that cause compilation to fail when they are exceeded.
+    ///
+    /// [limits]: https://cranelift.readthedocs.io/en/latest/ir.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 convenient alias for a `Result` that uses `CodegenError` as the error type.
+pub type CodegenResult<T> = Result<T, CodegenError>;
+
+impl From<VerifierErrors> for CodegenError {
+    fn from(e: VerifierErrors) -> Self {
+        CodegenError::Verifier(e)
+    }
+}