Add an "umbrella" crate, which seeks to provide a convenient interface.

This currently pulls in cretonne-codegen and cretonne-frontend and
provides a simple prelude interface.

This fixes #287.

lib/umbrella/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+authors = ["The Cretonne Project Developers"]
+name = "cretonne"
+version = "0.4.4"
+description = "Umbrella for commonly-used cretonne crates"
+license = "Apache-2.0"
+documentation = "https://cretonne.readthedocs.io/"
+repository = "https://github.com/cretonne/cretonne"
+readme = "README.md"
+keywords = ["compile", "compiler", "jit"]
+
+[dependencies]
+cretonne-codegen = { path = "../codegen", version = "0.4.4" }
+cretonne-frontend = { path = "../frontend", version = "0.4.4" }
+
+[badges]
+maintenance = { status = "experimental" }
+travis-ci = { repository = "cretonne/cretonne" }

lib/umbrella/README.md

@@ -0,0 +1,3 @@
+This is an umbrella crate which contains no code of its own, but pulls in
+other cretonne library crates to provide a convenient one-line dependency
+for common use cases.

lib/umbrella/src/lib.rs

@@ -0,0 +1,19 @@
+//! Cretonne umbrella crate, providing a convenient one-line dependency.
+
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
+#![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
+
+pub extern crate cretonne_codegen;
+pub extern crate cretonne_frontend;
+
+/// A prelude providing convenient access to commonly-used cretonne features. Use
+/// as `use cretonne::prelude::*`.
+pub mod prelude {
+    pub use cretonne_codegen;
+    pub use cretonne_codegen::entity::EntityRef;
+    pub use cretonne_codegen::ir::{AbiParam, InstBuilder, Value, Ebb, Signature, CallConv};
+    pub use cretonne_codegen::ir::types;
+    pub use cretonne_codegen::ir::condcodes::IntCC;
+
+    pub use cretonne_frontend::{FunctionBuilderContext, FunctionBuilder, Variable};
+}