diff --git a/cranelift/README.md b/cranelift/README.md
index b84e89bad1..b304a97891 100644
--- a/cranelift/README.md
+++ b/cranelift/README.md
@@ -79,6 +79,7 @@ Building with no\_std
 
 The following crates support \`no\_std\`:
  - cranelift-entity
+ - cranelift-bforest
  - cranelift-codegen
  - cranelift-frontend
  - cranelift-native
diff --git a/cranelift/publish-all.sh b/cranelift/publish-all.sh
index 67311f5f6f..089e7f27cb 100755
--- a/cranelift/publish-all.sh
+++ b/cranelift/publish-all.sh
@@ -36,7 +36,7 @@ cargo update
 echo git commit -a -m "\"Bump version to $version"\"
 echo git push
 for crate in \
-    entity codegen/meta codegen frontend native \
+    entity bforest codegen/meta codegen frontend native \
     reader wasm module simplejit \
     faerie umbrella
 do
diff --git a/lib/bforest/Cargo.toml b/lib/bforest/Cargo.toml
new file mode 100644
index 0000000000..4b1d1d076c
--- /dev/null
+++ b/lib/bforest/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+authors = ["The Cranelift Project Developers"]
+name = "cranelift-bforest"
+version = "0.18.1"
+description = "A forest of B+-trees"
+license = "Apache-2.0"
+documentation = "https://cranelift.readthedocs.io/"
+repository = "https://github.com/CraneStation/cranelift"
+readme = "README.md"
+keywords = ["btree", "forest", "set", "map"]
+
+[dependencies]
+cranelift-entity = { path = "../entity", version = "0.18.1", default-features = false }
+
+[features]
+default = ["std"]
+std = ["cranelift-entity/std"]
+
+[badges]
+maintenance = { status = "experimental" }
+travis-ci = { repository = "CraneStation/cranelift" }
diff --git a/lib/bforest/README.md b/lib/bforest/README.md
new file mode 100644
index 0000000000..718a4ed8fe
--- /dev/null
+++ b/lib/bforest/README.md
@@ -0,0 +1,2 @@
+This crate contains array-based data structures used by the core Cranelift code
+generator which represent a set of small ordered sets or maps.
diff --git a/lib/codegen/src/bforest/mod.rs b/lib/bforest/src/lib.rs
similarity index 79%
rename from lib/codegen/src/bforest/mod.rs
rename to lib/bforest/src/lib.rs
index bc22cf88c0..1bddcd8a73 100644
--- a/lib/codegen/src/bforest/mod.rs
+++ b/lib/bforest/src/lib.rs
@@ -1,6 +1,6 @@
 //! A forest of B+-trees.
 //!
-//! This module provides a data structures representing a set of small ordered sets or maps.
+//! This crate provides a data structures representing a set of small ordered sets or maps.
 //! It is implemented as a forest of B+-trees all allocating nodes out of the same pool.
 //!
 //! **These are not general purpose data structures that are somehow magically faster that the
@@ -13,6 +13,34 @@
 //! - Empty trees have a very small 32-bit footprint.
 //! - All the trees in a forest can be cleared in constant time.
 
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
+#![warn(unused_import_braces)]
+#![cfg_attr(feature = "std", warn(unstable_features))]
+#![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
+#![cfg_attr(feature = "cargo-clippy", allow(new_without_default, new_without_default_derive))]
+#![cfg_attr(
+    feature = "cargo-clippy",
+    warn(
+        float_arithmetic, mut_mut, nonminimal_bool, option_map_unwrap_or, option_map_unwrap_or_else,
+        print_stdout, unicode_not_nfc, use_self
+    )
+)]
+// 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))]
+
+/// This replaces `std` in builds with `core`.
+#[cfg(not(feature = "std"))]
+mod std {
+    extern crate alloc;
+    pub use self::alloc::{boxed, string, vec};
+    pub use core::*;
+}
+
+#[macro_use]
+extern crate cranelift_entity as entity;
+use entity::packed_option;
+
 use std::borrow::BorrowMut;
 use std::cmp::Ordering;
 
@@ -124,7 +152,11 @@ fn slice_shift<T: Copy>(s: &mut [T], n: usize) {
 mod test {
     use super::*;
     use entity::EntityRef;
-    use ir::Ebb;
+
+    /// An opaque reference to an extended basic block in a function.
+    #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+    pub struct Ebb(u32);
+    entity_impl!(Ebb, "ebb");
 
     #[test]
     fn comparator() {
diff --git a/lib/codegen/src/bforest/map.rs b/lib/bforest/src/map.rs
similarity index 100%
rename from lib/codegen/src/bforest/map.rs
rename to lib/bforest/src/map.rs
diff --git a/lib/codegen/src/bforest/node.rs b/lib/bforest/src/node.rs
similarity index 100%
rename from lib/codegen/src/bforest/node.rs
rename to lib/bforest/src/node.rs
diff --git a/lib/codegen/src/bforest/path.rs b/lib/bforest/src/path.rs
similarity index 100%
rename from lib/codegen/src/bforest/path.rs
rename to lib/bforest/src/path.rs
diff --git a/lib/codegen/src/bforest/pool.rs b/lib/bforest/src/pool.rs
similarity index 100%
rename from lib/codegen/src/bforest/pool.rs
rename to lib/bforest/src/pool.rs
diff --git a/lib/codegen/src/bforest/set.rs b/lib/bforest/src/set.rs
similarity index 100%
rename from lib/codegen/src/bforest/set.rs
rename to lib/bforest/src/set.rs
diff --git a/lib/codegen/Cargo.toml b/lib/codegen/Cargo.toml
index bb767dd67f..5bddad6418 100644
--- a/lib/codegen/Cargo.toml
+++ b/lib/codegen/Cargo.toml
@@ -12,6 +12,7 @@ build = "build.rs"
 
 [dependencies]
 cranelift-entity = { path = "../entity", version = "0.18.1", default-features = false }
+cranelift-bforest = { path = "../bforest", version = "0.18.1", default-features = false }
 failure = { version = "0.1.1", default-features = false, features = ["derive"] }
 failure_derive = { version = "0.1.1", default-features = false }
 hashmap_core = { version = "0.1.9", optional = true }
@@ -29,7 +30,7 @@ cranelift-codegen-meta = { path = "meta", version = "0.18.1" }
 # of some minimal std-like replacement libraries. At least one of these two
 # features need to be enabled.
 default = ["std"]
-std = ["cranelift-entity/std", "target-lexicon/std"]
+std = ["cranelift-entity/std", "cranelift-bforest/std", "target-lexicon/std"]
 core = ["hashmap_core"]
 
 [badges]
diff --git a/lib/codegen/src/lib.rs b/lib/codegen/src/lib.rs
index 5d24ddf709..23959e67ac 100644
--- a/lib/codegen/src/lib.rs
+++ b/lib/codegen/src/lib.rs
@@ -60,10 +60,11 @@ pub const VERSION: &str = env!("CARGO_PKG_VERSION");
 #[macro_use]
 pub extern crate cranelift_entity as entity;
 
+pub extern crate cranelift_bforest as bforest;
+
 #[macro_use]
 pub mod dbg;
 
-pub mod bforest;
 pub mod binemit;
 pub mod cfg_printer;
 pub mod cursor;