diff --git a/lib/environ/Cargo.toml b/lib/environ/Cargo.toml
index 7681f8bb6e..8de7232bdf 100644
--- a/lib/environ/Cargo.toml
+++ b/lib/environ/Cargo.toml
@@ -15,6 +15,11 @@ cranelift-entity = "0.24.0"
 cranelift-wasm = "0.24.0"
 memoffset = "0.2.1"
 
+[features]
+default = ["std"]
+std = ["cranelift-codegen/std", "cranelift-wasm/std"]
+core = ["cranelift-codegen/core", "cranelift-wasm/core"]
+
 [badges]
 maintenance = { status = "experimental" }
 travis-ci = { repository = "CraneStation/wasmtime" }
diff --git a/lib/environ/src/compilation.rs b/lib/environ/src/compilation.rs
index 55a84eddfa..d6d82d6644 100644
--- a/lib/environ/src/compilation.rs
+++ b/lib/environ/src/compilation.rs
@@ -9,6 +9,8 @@ use cranelift_codegen::Context;
 use cranelift_entity::{EntityRef, PrimaryMap};
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex, FuncTranslator};
 use environ::{get_func_name, ModuleTranslation};
+use std::string::{String, ToString};
+use std::vec::Vec;
 
 /// The result of compiling a WebAssemby module's functions.
 #[derive(Debug)]
diff --git a/lib/environ/src/environ.rs b/lib/environ/src/environ.rs
index 295b69ff07..122c8f84d0 100644
--- a/lib/environ/src/environ.rs
+++ b/lib/environ/src/environ.rs
@@ -13,6 +13,8 @@ use cranelift_wasm::{
 };
 use module::{DataInitializer, Export, LazyContents, Module, TableElements};
 use std::mem;
+use std::string::String;
+use std::vec::Vec;
 use vmcontext;
 
 /// Compute a `ir::ExternalName` for a given wasm function index.
diff --git a/lib/environ/src/lib.rs b/lib/environ/src/lib.rs
index 4ad0c82ad6..7701756069 100644
--- a/lib/environ/src/lib.rs
+++ b/lib/environ/src/lib.rs
@@ -3,13 +3,9 @@
 //! the translation the base addresses of regions of memory that will hold the globals, tables and
 //! linear memories.
 
-#![deny(
-    missing_docs,
-    trivial_numeric_casts,
-    unused_extern_crates,
-    unstable_features
-)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(
     feature = "clippy",
     plugin(clippy(conf_file = "../../clippy.toml"))
@@ -31,12 +27,17 @@
         use_self
     )
 )]
+#![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(not(feature = "std"), feature(alloc))]
 
 extern crate cranelift_codegen;
 extern crate cranelift_entity;
 extern crate cranelift_wasm;
 #[macro_use]
 extern crate memoffset;
+#[cfg(not(feature = "std"))]
+#[macro_use]
+extern crate alloc;
 
 mod compilation;
 mod environ;
@@ -46,3 +47,10 @@ mod vmcontext;
 pub use compilation::{compile_module, Compilation, Relocation, RelocationTarget, Relocations};
 pub use environ::{ModuleEnvironment, ModuleTranslation};
 pub use module::{DataInitializer, Module, TableElements};
+
+#[cfg(not(feature = "std"))]
+mod std {
+    pub use alloc::{string, vec};
+    pub use core::*;
+    pub use core::{i32, str, u32};
+}
diff --git a/lib/environ/src/module.rs b/lib/environ/src/module.rs
index 3e0391e04a..c9bed3266c 100644
--- a/lib/environ/src/module.rs
+++ b/lib/environ/src/module.rs
@@ -7,6 +7,8 @@ use cranelift_wasm::{
     TableIndex,
 };
 use std::collections::HashMap;
+use std::string::String;
+use std::vec::Vec;
 
 /// A WebAssembly table initializer.
 #[derive(Clone, Debug)]
diff --git a/lib/execute/Cargo.toml b/lib/execute/Cargo.toml
index f98a3ecaed..6938ebf9bf 100644
--- a/lib/execute/Cargo.toml
+++ b/lib/execute/Cargo.toml
@@ -7,6 +7,7 @@ description = "JIT-style execution for WebAsssembly code in Cranelift"
 categories = ["wasm"]
 repository = "https://github.com/CraneStation/wasmtime"
 license = "Apache-2.0 WITH LLVM-exception"
+readme = "README.md"
 
 [dependencies]
 cranelift-codegen = "0.24.0"
@@ -15,3 +16,12 @@ cranelift-wasm = "0.24.0"
 region = "1.0.0"
 wasmtime-environ = { path = "../environ" }
 memmap = "0.7.0"
+
+[features]
+default = ["std"]
+std = ["cranelift-codegen/std", "cranelift-wasm/std"]
+core = ["cranelift-codegen/core", "cranelift-wasm/core", "wasmtime-environ/core"]
+
+[badges]
+maintenance = { status = "experimental" }
+travis-ci = { repository = "CraneStation/wasmtime" }
diff --git a/lib/execute/README.md b/lib/execute/README.md
new file mode 100644
index 0000000000..13fb3d6a1d
--- /dev/null
+++ b/lib/execute/README.md
@@ -0,0 +1,4 @@
+This is the `wasmtime-execute` crate, which contains wasm runtime support,
+supporting the wasm ABI defined by [`wasmtime-environ`].
+
+[`wasmtime-environ`]: https://crates.io/crates/wasmtime-environ
diff --git a/lib/execute/src/execute.rs b/lib/execute/src/execute.rs
index 1fd1092c59..cecc05fc17 100644
--- a/lib/execute/src/execute.rs
+++ b/lib/execute/src/execute.rs
@@ -8,6 +8,8 @@ use region::protect;
 use region::Protection;
 use std::mem::transmute;
 use std::ptr::{self, write_unaligned};
+use std::string::String;
+use std::vec::Vec;
 use wasmtime_environ::{
     compile_module, Compilation, Module, ModuleTranslation, Relocation, RelocationTarget,
 };
diff --git a/lib/execute/src/instance.rs b/lib/execute/src/instance.rs
index d9d214a7d2..36ade34767 100644
--- a/lib/execute/src/instance.rs
+++ b/lib/execute/src/instance.rs
@@ -6,6 +6,7 @@ use cranelift_entity::EntityRef;
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::{GlobalIndex, MemoryIndex, TableIndex};
 use memory::LinearMemory;
+use std::vec::Vec;
 use wasmtime_environ::{Compilation, DataInitializer, Module, TableElements};
 
 /// An Instance of a WebAssemby module.
diff --git a/lib/execute/src/lib.rs b/lib/execute/src/lib.rs
index 3bf2646cd4..f5adfa6ab4 100644
--- a/lib/execute/src/lib.rs
+++ b/lib/execute/src/lib.rs
@@ -1,12 +1,8 @@
 //! JIT-style runtime for WebAssembly using Cranelift.
 
-#![deny(
-    missing_docs,
-    trivial_numeric_casts,
-    unused_extern_crates,
-    unstable_features
-)]
+#![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
 #![warn(unused_import_braces)]
+#![cfg_attr(feature = "std", deny(unstable_features))]
 #![cfg_attr(
     feature = "clippy",
     plugin(clippy(conf_file = "../../clippy.toml"))
@@ -28,6 +24,8 @@
         use_self
     )
 )]
+#![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(not(feature = "std"), feature(alloc))]
 
 extern crate cranelift_codegen;
 extern crate cranelift_entity;
@@ -35,6 +33,9 @@ extern crate cranelift_wasm;
 extern crate memmap;
 extern crate region;
 extern crate wasmtime_environ;
+#[cfg(not(feature = "std"))]
+#[macro_use]
+extern crate alloc;
 
 mod execute;
 mod instance;
@@ -42,3 +43,10 @@ mod memory;
 
 pub use execute::{compile_and_link_module, execute};
 pub use instance::Instance;
+
+#[cfg(not(feature = "std"))]
+mod std {
+    pub use alloc::{string, vec};
+    pub use core::*;
+    pub use core::{i32, str, u32};
+}