diff --git a/crates/api/Cargo.toml b/crates/api/Cargo.toml
index 5289480ebc..93cdffcd44 100644
--- a/crates/api/Cargo.toml
+++ b/crates/api/Cargo.toml
@@ -26,23 +26,6 @@ target-lexicon = { version = "0.9.0", default-features = false }
 anyhow = "1.0.19"
 thiserror = "1.0.4"
 region = "2.0.0"
-hashbrown = { version = "0.6.0", optional = true }
-
-[features]
-default = ["std"]
-std = [
-    "cranelift-codegen/std",
-    "cranelift-wasm/std",
-    "wasmtime-environ/std",
-    "wasmparser/std"
-]
-core = [
-    "hashbrown/nightly",
-    "cranelift-codegen/core",
-    "cranelift-wasm/core",
-    "wasmtime-environ/core",
-    "wasmparser/core"
-]
 
 [dev-dependencies]
 # for wasmtime.rs
diff --git a/crates/api/examples/hello.rs b/crates/api/examples/hello.rs
index 2f517a3e86..7e99ec0477 100644
--- a/crates/api/examples/hello.rs
+++ b/crates/api/examples/hello.rs
@@ -1,7 +1,7 @@
 //! Translation of hello example
 
 use anyhow::{ensure, format_err, Context as _, Result};
-use core::cell::Ref;
+use std::cell::Ref;
 use std::rc::Rc;
 use wasmtime_api::*;
 
diff --git a/crates/api/src/callable.rs b/crates/api/src/callable.rs
index 2a86789377..b6b51f8786 100644
--- a/crates/api/src/callable.rs
+++ b/crates/api/src/callable.rs
@@ -4,8 +4,8 @@ use crate::trampoline::generate_func_export;
 use crate::trap::Trap;
 use crate::types::FuncType;
 use crate::values::Val;
-use alloc::{rc::Rc, vec::Vec};
 use cranelift_codegen::ir;
+use std::rc::Rc;
 use wasmtime_jit::InstanceHandle;
 use wasmtime_runtime::Export;
 
@@ -43,8 +43,8 @@ impl WasmtimeFn {
 
 impl WrappedCallable for WasmtimeFn {
     fn call(&self, params: &[Val], results: &mut [Val]) -> Result<(), HostRef<Trap>> {
-        use core::cmp::max;
-        use core::{mem, ptr};
+        use std::cmp::max;
+        use std::{mem, ptr};
 
         let (vmctx, body, signature) = match self.wasmtime_export() {
             Export::Function {
diff --git a/crates/api/src/context.rs b/crates/api/src/context.rs
index 3c004db1ce..407652e17c 100644
--- a/crates/api/src/context.rs
+++ b/crates/api/src/context.rs
@@ -1,7 +1,7 @@
 use crate::Config;
-use alloc::rc::Rc;
-use core::cell::{RefCell, RefMut};
-use core::hash::{Hash, Hasher};
+use std::cell::{RefCell, RefMut};
+use std::hash::{Hash, Hasher};
+use std::rc::Rc;
 use wasmtime_jit::{Compiler, Features};
 
 #[derive(Clone)]
diff --git a/crates/api/src/externals.rs b/crates/api/src/externals.rs
index c5a6325be5..3b8748c6cd 100644
--- a/crates/api/src/externals.rs
+++ b/crates/api/src/externals.rs
@@ -5,10 +5,9 @@ use crate::trampoline::{generate_global_export, generate_memory_export, generate
 use crate::trap::Trap;
 use crate::types::{ExternType, FuncType, GlobalType, MemoryType, TableType, ValType};
 use crate::values::{from_checked_anyfunc, into_checked_anyfunc, Val};
-use alloc::boxed::Box;
-use alloc::rc::Rc;
-use core::result::Result;
-use core::slice;
+use std::fmt;
+use std::rc::Rc;
+use std::slice;
 use wasmtime_runtime::InstanceHandle;
 
 // Externals
@@ -172,8 +171,8 @@ impl Func {
     }
 }
 
-impl core::fmt::Debug for Func {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl fmt::Debug for Func {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "Func")
     }
 }
diff --git a/crates/api/src/instance.rs b/crates/api/src/instance.rs
index b5d433fe2d..0f6d1b38bf 100644
--- a/crates/api/src/instance.rs
+++ b/crates/api/src/instance.rs
@@ -4,11 +4,10 @@ use crate::module::Module;
 use crate::r#ref::HostRef;
 use crate::runtime::Store;
 use crate::types::{ExportType, ExternType, Name};
-use crate::{HashMap, HashSet};
-use alloc::string::{String, ToString};
-use alloc::{boxed::Box, rc::Rc, vec::Vec};
 use anyhow::Result;
-use core::cell::RefCell;
+use std::cell::RefCell;
+use std::collections::{HashMap, HashSet};
+use std::rc::Rc;
 use wasmtime_jit::{instantiate, Resolver};
 use wasmtime_runtime::{Export, InstanceHandle};
 
diff --git a/crates/api/src/lib.rs b/crates/api/src/lib.rs
index 54039179b6..c817c3dcc2 100644
--- a/crates/api/src/lib.rs
+++ b/crates/api/src/lib.rs
@@ -1,7 +1,6 @@
 //! Wasmtime embed API. Based on wasm-c-api.
 
 #![allow(improper_ctypes)]
-#![cfg_attr(not(feature = "std"), no_std)]
 
 mod callable;
 mod context;
@@ -17,8 +16,6 @@ mod values;
 
 pub mod wasm;
 
-extern crate alloc;
-
 pub use crate::callable::Callable;
 pub use crate::externals::*;
 pub use crate::instance::Instance;
@@ -28,8 +25,3 @@ pub use crate::runtime::{Config, Engine, Store};
 pub use crate::trap::Trap;
 pub use crate::types::*;
 pub use crate::values::*;
-
-#[cfg(not(feature = "std"))]
-use hashbrown::{hash_map, HashMap, HashSet};
-#[cfg(feature = "std")]
-use std::collections::{hash_map, HashMap, HashSet};
diff --git a/crates/api/src/module.rs b/crates/api/src/module.rs
index 26efc9e74d..6cc44c3a10 100644
--- a/crates/api/src/module.rs
+++ b/crates/api/src/module.rs
@@ -4,7 +4,6 @@ use crate::types::{
     ExportType, ExternType, FuncType, GlobalType, ImportType, Limits, MemoryType, Mutability,
     TableType, ValType,
 };
-use alloc::{boxed::Box, string::String, vec::Vec};
 use anyhow::Result;
 use wasmparser::{validate, ExternalKind, ImportSectionEntryType, ModuleReader, SectionCode};
 
@@ -12,7 +11,7 @@ fn into_memory_type(mt: wasmparser::MemoryType) -> MemoryType {
     assert!(!mt.shared);
     MemoryType::new(Limits::new(
         mt.limits.initial,
-        mt.limits.maximum.unwrap_or(::core::u32::MAX),
+        mt.limits.maximum.unwrap_or(std::u32::MAX),
     ))
 }
 
@@ -53,7 +52,7 @@ fn into_table_type(tt: wasmparser::TableType) -> TableType {
     let ty = into_valtype(&tt.element_type);
     let limits = Limits::new(
         tt.limits.initial,
-        tt.limits.maximum.unwrap_or(::core::u32::MAX),
+        tt.limits.maximum.unwrap_or(std::u32::MAX),
     );
     TableType::new(ty, limits)
 }
diff --git a/crates/api/src/ref.rs b/crates/api/src/ref.rs
index 098ec639e4..c6010c0624 100644
--- a/crates/api/src/ref.rs
+++ b/crates/api/src/ref.rs
@@ -1,8 +1,7 @@
-use alloc::boxed::Box;
-use alloc::rc::{Rc, Weak};
-use core::any::Any;
-use core::cell::{self, RefCell};
-use core::fmt;
+use std::any::Any;
+use std::cell::{self, RefCell};
+use std::fmt;
+use std::rc::{Rc, Weak};
 
 pub trait HostInfo {
     fn finalize(&mut self) {}
diff --git a/crates/api/src/runtime.rs b/crates/api/src/runtime.rs
index 2b7e462ff2..b87b09f3d4 100644
--- a/crates/api/src/runtime.rs
+++ b/crates/api/src/runtime.rs
@@ -1,9 +1,9 @@
 use crate::context::Context;
 use crate::r#ref::HostRef;
-use crate::HashMap;
-use alloc::{rc::Rc, string::String};
-use core::cell::RefCell;
 use cranelift_codegen::{ir, settings};
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::rc::Rc;
 use wasmtime_jit::{CompilationStrategy, Features};
 
 // Runtime Environment
@@ -143,7 +143,7 @@ impl Store {
         &mut self,
         signature: &ir::Signature,
     ) -> wasmtime_runtime::VMSharedSignatureIndex {
-        use crate::hash_map::Entry;
+        use std::collections::hash_map::Entry;
         let index = self.context().compiler().signatures().register(signature);
         match self.signature_cache.entry(index) {
             Entry::Vacant(v) => {
diff --git a/crates/api/src/trampoline/create_handle.rs b/crates/api/src/trampoline/create_handle.rs
index a4a6f780ee..bddc5f10f1 100644
--- a/crates/api/src/trampoline/create_handle.rs
+++ b/crates/api/src/trampoline/create_handle.rs
@@ -1,16 +1,13 @@
 //! Support for a calling of an imported function.
 
 use crate::runtime::Store;
-use crate::{HashMap, HashSet};
-use alloc::boxed::Box;
-use alloc::rc::Rc;
-use alloc::string::String;
-use alloc::vec::Vec;
 use anyhow::Result;
-use core::any::Any;
-use core::cell::{RefCell, RefMut};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::DefinedFuncIndex;
+use std::any::Any;
+use std::cell::{RefCell, RefMut};
+use std::collections::{HashMap, HashSet};
+use std::rc::Rc;
 use wasmtime_environ::Module;
 use wasmtime_runtime::{Imports, InstanceHandle, VMFunctionBody};
 
diff --git a/crates/api/src/trampoline/func.rs b/crates/api/src/trampoline/func.rs
index de3b4b2e3d..d5841365d2 100644
--- a/crates/api/src/trampoline/func.rs
+++ b/crates/api/src/trampoline/func.rs
@@ -3,15 +3,15 @@
 use super::create_handle::create_handle;
 use crate::r#ref::HostRef;
 use crate::{Callable, FuncType, Store, Trap, Val};
-use alloc::{boxed::Box, rc::Rc, string::ToString, vec::Vec};
 use anyhow::Result;
-use core::cmp;
 use cranelift_codegen::ir::{types, InstBuilder, StackSlotData, StackSlotKind, TrapCode};
 use cranelift_codegen::print_errors::pretty_error;
 use cranelift_codegen::{binemit, ir, isa, Context};
 use cranelift_entity::{EntityRef, PrimaryMap};
 use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex};
+use std::cmp;
+use std::rc::Rc;
 use wasmtime_environ::{CompiledFunction, Export, Module};
 use wasmtime_jit::CodeMemory;
 use wasmtime_runtime::{InstanceHandle, VMContext, VMFunctionBody};
diff --git a/crates/api/src/trampoline/global.rs b/crates/api/src/trampoline/global.rs
index 7e96618a76..914fa7f3d9 100644
--- a/crates/api/src/trampoline/global.rs
+++ b/crates/api/src/trampoline/global.rs
@@ -1,6 +1,5 @@
 use super::create_handle::create_handle;
 use crate::{GlobalType, Mutability, Val};
-use alloc::boxed::Box;
 use anyhow::Result;
 use cranelift_entity::PrimaryMap;
 use wasmtime_environ::Module;
diff --git a/crates/api/src/trampoline/memory.rs b/crates/api/src/trampoline/memory.rs
index 898fb71d8e..b54e847779 100644
--- a/crates/api/src/trampoline/memory.rs
+++ b/crates/api/src/trampoline/memory.rs
@@ -1,7 +1,5 @@
 use super::create_handle::create_handle;
 use crate::MemoryType;
-use alloc::boxed::Box;
-use alloc::string::ToString;
 use anyhow::Result;
 use cranelift_entity::PrimaryMap;
 use wasmtime_environ::Module;
@@ -14,7 +12,7 @@ pub fn create_handle_with_memory(memory: &MemoryType) -> Result<InstanceHandle>
 
     let memory = cranelift_wasm::Memory {
         minimum: memory.limits().min(),
-        maximum: if memory.limits().max() == core::u32::MAX {
+        maximum: if memory.limits().max() == std::u32::MAX {
             None
         } else {
             Some(memory.limits().max())
diff --git a/crates/api/src/trampoline/mod.rs b/crates/api/src/trampoline/mod.rs
index 6b5dbf1220..2ede995444 100644
--- a/crates/api/src/trampoline/mod.rs
+++ b/crates/api/src/trampoline/mod.rs
@@ -12,8 +12,8 @@ use self::memory::create_handle_with_memory;
 use self::table::create_handle_with_table;
 use super::{Callable, FuncType, GlobalType, MemoryType, Store, TableType, Val};
 use crate::r#ref::HostRef;
-use alloc::rc::Rc;
 use anyhow::Result;
+use std::rc::Rc;
 
 pub use self::global::GlobalState;
 
diff --git a/crates/api/src/trampoline/table.rs b/crates/api/src/trampoline/table.rs
index 692d43164d..6c11d25edb 100644
--- a/crates/api/src/trampoline/table.rs
+++ b/crates/api/src/trampoline/table.rs
@@ -1,7 +1,5 @@
 use super::create_handle::create_handle;
 use crate::{TableType, ValType};
-use alloc::boxed::Box;
-use alloc::string::ToString;
 use anyhow::Result;
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::TableElementType;
@@ -13,7 +11,7 @@ pub fn create_handle_with_table(table: &TableType) -> Result<InstanceHandle> {
 
     let table = cranelift_wasm::Table {
         minimum: table.limits().min(),
-        maximum: if table.limits().max() == core::u32::MAX {
+        maximum: if table.limits().max() == std::u32::MAX {
             None
         } else {
             Some(table.limits().max())
diff --git a/crates/api/src/trap.rs b/crates/api/src/trap.rs
index 4010a1eef9..77628138bd 100644
--- a/crates/api/src/trap.rs
+++ b/crates/api/src/trap.rs
@@ -1,4 +1,3 @@
-use alloc::string::{String, ToString};
 use thiserror::Error;
 
 #[derive(Error, Debug)]
diff --git a/crates/api/src/types.rs b/crates/api/src/types.rs
index 0f32b27953..9b50a1f2b5 100644
--- a/crates/api/src/types.rs
+++ b/crates/api/src/types.rs
@@ -1,7 +1,3 @@
-use alloc::borrow::ToOwned;
-use alloc::boxed::Box;
-use alloc::string::String;
-use alloc::vec::Vec;
 use cranelift_codegen::ir;
 
 // Type Representations
@@ -28,7 +24,7 @@ impl Limits {
     pub fn at_least(min: u32) -> Limits {
         Limits {
             min,
-            max: ::core::u32::MAX,
+            max: ::std::u32::MAX,
         }
     }
 
@@ -277,7 +273,7 @@ impl TableType {
             false
         });
         let ty = ValType::FuncRef;
-        let limits = Limits::new(table.minimum, table.maximum.unwrap_or(::core::u32::MAX));
+        let limits = Limits::new(table.minimum, table.maximum.unwrap_or(::std::u32::MAX));
         TableType::new(ty, limits)
     }
 }
@@ -300,7 +296,7 @@ impl MemoryType {
     pub(crate) fn from_cranelift_memory(memory: &cranelift_wasm::Memory) -> MemoryType {
         MemoryType::new(Limits::new(
             memory.minimum,
-            memory.maximum.unwrap_or(::core::u32::MAX),
+            memory.maximum.unwrap_or(::std::u32::MAX),
         ))
     }
 }
@@ -326,7 +322,7 @@ impl From<String> for Name {
     }
 }
 
-impl ::alloc::string::ToString for Name {
+impl ToString for Name {
     fn to_string(&self) -> String {
         self.0.to_owned()
     }
diff --git a/crates/api/src/values.rs b/crates/api/src/values.rs
index 42163b119d..c82dc69229 100644
--- a/crates/api/src/values.rs
+++ b/crates/api/src/values.rs
@@ -2,8 +2,8 @@ use crate::externals::Func;
 use crate::r#ref::{AnyRef, HostRef};
 use crate::runtime::Store;
 use crate::types::ValType;
-use core::ptr;
 use cranelift_codegen::ir;
+use std::ptr;
 use wasmtime_jit::RuntimeValue;
 
 #[derive(Debug, Clone)]
diff --git a/crates/api/src/wasm.rs b/crates/api/src/wasm.rs
index 4c4f545170..b8fe7fad34 100644
--- a/crates/api/src/wasm.rs
+++ b/crates/api/src/wasm.rs
@@ -10,9 +10,8 @@ use super::{
     HostInfo, HostRef, ImportType, Instance, Limits, Memory, MemoryType, Module, Name, Store,
     Table, TableType, Trap, Val, ValType,
 };
-use alloc::boxed::Box;
-use alloc::rc::Rc;
-use core::{mem, ptr, slice};
+use std::rc::Rc;
+use std::{mem, ptr, slice};
 
 macro_rules! declare_vec {
     ($name:ident, $elem_ty:path) => {
@@ -343,12 +342,12 @@ pub struct wasm_func_t {
     func: HostRef<Func>,
     ext: Option<Box<wasm_extern_t>>,
 }
-pub type wasm_func_callback_t = ::core::option::Option<
+pub type wasm_func_callback_t = std::option::Option<
     unsafe extern "C" fn(args: *const wasm_val_t, results: *mut wasm_val_t) -> *mut wasm_trap_t,
 >;
-pub type wasm_func_callback_with_env_t = ::core::option::Option<
+pub type wasm_func_callback_with_env_t = std::option::Option<
     unsafe extern "C" fn(
-        env: *mut ::core::ffi::c_void,
+        env: *mut std::ffi::c_void,
         args: *const wasm_val_t,
         results: *mut wasm_val_t,
     ) -> *mut wasm_trap_t,
@@ -567,8 +566,8 @@ impl Into<HostRef<Trap>> for wasm_trap_t {
 
 struct CallbackWithEnv {
     callback: wasm_func_callback_with_env_t,
-    env: *mut ::core::ffi::c_void,
-    finalizer: ::core::option::Option<unsafe extern "C" fn(env: *mut ::core::ffi::c_void)>,
+    env: *mut std::ffi::c_void,
+    finalizer: std::option::Option<unsafe extern "C" fn(env: *mut std::ffi::c_void)>,
 }
 
 impl Callable for CallbackWithEnv {
@@ -799,8 +798,8 @@ pub unsafe extern "C" fn wasm_func_new_with_env(
     store: *mut wasm_store_t,
     ty: *const wasm_functype_t,
     callback: wasm_func_callback_with_env_t,
-    env: *mut ::core::ffi::c_void,
-    finalizer: ::core::option::Option<unsafe extern "C" fn(arg1: *mut ::core::ffi::c_void)>,
+    env: *mut std::ffi::c_void,
+    finalizer: std::option::Option<unsafe extern "C" fn(arg1: *mut std::ffi::c_void)>,
 ) -> *mut wasm_func_t {
     let store = &(*store).store;
     let ty = (*ty).functype.clone();
@@ -1614,8 +1613,8 @@ pub unsafe extern "C" fn wasm_tabletype_new(
 }
 
 struct HostInfoState {
-    info: *mut ::core::ffi::c_void,
-    finalizer: ::core::option::Option<unsafe extern "C" fn(arg1: *mut ::core::ffi::c_void)>,
+    info: *mut std::ffi::c_void,
+    finalizer: std::option::Option<unsafe extern "C" fn(arg1: *mut std::ffi::c_void)>,
 }
 
 impl HostInfo for HostInfoState {
@@ -1631,8 +1630,8 @@ impl HostInfo for HostInfoState {
 #[no_mangle]
 pub unsafe extern "C" fn wasm_instance_set_host_info_with_finalizer(
     instance: *mut wasm_instance_t,
-    info: *mut ::core::ffi::c_void,
-    finalizer: ::core::option::Option<unsafe extern "C" fn(arg1: *mut ::core::ffi::c_void)>,
+    info: *mut std::ffi::c_void,
+    finalizer: std::option::Option<unsafe extern "C" fn(arg1: *mut std::ffi::c_void)>,
 ) {
     let info = if info.is_null() && finalizer.is_none() {
         None
diff --git a/crates/debug/Cargo.toml b/crates/debug/Cargo.toml
index e83e1e62c7..6ded069424 100644
--- a/crates/debug/Cargo.toml
+++ b/crates/debug/Cargo.toml
@@ -18,17 +18,11 @@ cranelift-codegen = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-entity = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-wasm = { version = "0.50.0", features = ["enable-serde"] }
 faerie = "0.13.0"
-wasmtime-environ = { path = "../environ", default-features = false }
+wasmtime-environ = { path = "../environ" }
 target-lexicon = { version = "0.9.0", default-features = false }
 anyhow = "1.0"
-hashbrown = { version = "0.6.0", optional = true }
 thiserror = "1.0.4"
 more-asserts = "0.2.1"
 
-[features]
-default = ["std"]
-std = ["cranelift-codegen/std", "cranelift-wasm/std", "wasmtime-environ/std"]
-core = ["hashbrown/nightly", "cranelift-codegen/core", "cranelift-wasm/core"]
-
 [badges]
 maintenance = { status = "actively-developed" }
diff --git a/crates/debug/src/gc.rs b/crates/debug/src/gc.rs
index edd4344705..9ac8ef7605 100644
--- a/crates/debug/src/gc.rs
+++ b/crates/debug/src/gc.rs
@@ -1,9 +1,8 @@
 use crate::transform::AddressTransform;
-use crate::{HashMap, HashSet};
-use alloc::vec::Vec;
 use gimli::constants;
 use gimli::read;
 use gimli::{Reader, UnitSectionOffset};
+use std::collections::{HashMap, HashSet};
 
 #[derive(Debug)]
 pub struct Dependencies {
@@ -20,7 +19,7 @@ impl Dependencies {
     }
 
     fn add_edge(&mut self, a: UnitSectionOffset, b: UnitSectionOffset) {
-        use crate::hash_map::Entry;
+        use std::collections::hash_map::Entry;
         match self.edges.entry(a) {
             Entry::Occupied(mut o) => {
                 o.get_mut().insert(b);
diff --git a/crates/debug/src/lib.rs b/crates/debug/src/lib.rs
index be46544bd2..9cbce9d60a 100644
--- a/crates/debug/src/lib.rs
+++ b/crates/debug/src/lib.rs
@@ -2,16 +2,10 @@
 
 #![allow(clippy::cast_ptr_alignment)]
 
-use alloc::string::String;
-use alloc::vec::Vec;
 use anyhow::Error;
 use cranelift_codegen::isa::TargetFrontendConfig;
 use faerie::{Artifact, Decl};
-#[cfg(not(feature = "std"))]
-use hashbrown::{hash_map, HashMap, HashSet};
 use more_asserts::assert_gt;
-#[cfg(feature = "std")]
-use std::collections::{hash_map, HashMap, HashSet};
 use target_lexicon::{BinaryFormat, Triple};
 use wasmtime_environ::{ModuleAddressMap, ModuleVmctxInfo, ValueLabelsRanges};
 
@@ -24,8 +18,6 @@ mod read_debuginfo;
 mod transform;
 mod write_debuginfo;
 
-extern crate alloc;
-
 struct FunctionRelocResolver {}
 impl SymbolResolver for FunctionRelocResolver {
     fn resolve_symbol(&self, symbol: usize, addend: i64) -> ResolvedSymbol {
@@ -80,12 +72,12 @@ pub fn emit_debugsections_image(
     assert_gt!(funcs.len(), 0);
     let mut segment_body: (usize, usize) = (!0, 0);
     for (body_ptr, body_len) in funcs {
-        segment_body.0 = ::core::cmp::min(segment_body.0, *body_ptr as usize);
-        segment_body.1 = ::core::cmp::max(segment_body.1, *body_ptr as usize + body_len);
+        segment_body.0 = std::cmp::min(segment_body.0, *body_ptr as usize);
+        segment_body.1 = std::cmp::max(segment_body.1, *body_ptr as usize + body_len);
     }
     let segment_body = (segment_body.0 as *const u8, segment_body.1 - segment_body.0);
 
-    let body = unsafe { ::core::slice::from_raw_parts(segment_body.0, segment_body.1) };
+    let body = unsafe { std::slice::from_raw_parts(segment_body.0, segment_body.1) };
     obj.declare_with("all", Decl::function(), body.to_vec())?;
 
     emit_dwarf(&mut obj, dwarf, &resolver)?;
diff --git a/crates/debug/src/read_debuginfo.rs b/crates/debug/src/read_debuginfo.rs
index 470e7e44b9..25b4e3fbc4 100644
--- a/crates/debug/src/read_debuginfo.rs
+++ b/crates/debug/src/read_debuginfo.rs
@@ -1,4 +1,3 @@
-use alloc::{boxed::Box, string::String, vec::Vec};
 use gimli::{
     DebugAbbrev, DebugAddr, DebugInfo, DebugLine, DebugLineStr, DebugLoc, DebugLocLists,
     DebugRanges, DebugRngLists, DebugStr, DebugStrOffsets, DebugTypes, EndianSlice, LittleEndian,
diff --git a/crates/debug/src/transform/address_transform.rs b/crates/debug/src/transform/address_transform.rs
index 823e8f4957..43ecf0b8c8 100644
--- a/crates/debug/src/transform/address_transform.rs
+++ b/crates/debug/src/transform/address_transform.rs
@@ -1,14 +1,12 @@
-use crate::HashMap;
 use crate::WasmFileInfo;
-use alloc::boxed::Box;
-use alloc::collections::BTreeMap;
-use alloc::vec::Vec;
-use core::iter::FromIterator;
 use cranelift_codegen::ir::SourceLoc;
 use cranelift_entity::{EntityRef, PrimaryMap};
 use cranelift_wasm::DefinedFuncIndex;
 use gimli::write;
 use more_asserts::assert_le;
+use std::collections::BTreeMap;
+use std::collections::HashMap;
+use std::iter::FromIterator;
 use wasmtime_environ::{FunctionAddressMap, ModuleAddressMap};
 
 pub type GeneratedAddress = usize;
@@ -163,7 +161,7 @@ fn build_function_lookup(
                 active_ranges.clone().into_boxed_slice(),
             );
         }
-        active_ranges.retain(|r| ranges[*r].wasm_end.cmp(&wasm_start) != core::cmp::Ordering::Less);
+        active_ranges.retain(|r| ranges[*r].wasm_end.cmp(&wasm_start) != std::cmp::Ordering::Less);
         active_ranges.push(range_index);
         last_wasm_pos = Some(wasm_start);
     }
@@ -494,10 +492,10 @@ impl AddressTransform {
 mod tests {
     use super::{build_function_lookup, get_wasm_code_offset, AddressTransform};
     use crate::read_debuginfo::WasmFileInfo;
-    use core::iter::FromIterator;
     use cranelift_codegen::ir::SourceLoc;
     use cranelift_entity::PrimaryMap;
     use gimli::write::Address;
+    use std::iter::FromIterator;
     use wasmtime_environ::{FunctionAddressMap, InstructionAddressMap, ModuleAddressMap};
 
     #[test]
diff --git a/crates/debug/src/transform/attr.rs b/crates/debug/src/transform/attr.rs
index 755441565e..5dcb7e4d9d 100644
--- a/crates/debug/src/transform/attr.rs
+++ b/crates/debug/src/transform/attr.rs
@@ -3,12 +3,11 @@ use super::expression::{compile_expression, CompiledExpression, FunctionFrameInf
 use super::range_info_builder::RangeInfoBuilder;
 use super::unit::PendingDieRef;
 use super::{DebugInputContext, Reader, TransformError};
-use crate::HashMap;
-use alloc::vec::Vec;
 use anyhow::Error;
 use gimli::{
     write, AttributeValue, DebugLineOffset, DebugStr, DebuggingInformationEntry, UnitOffset,
 };
+use std::collections::HashMap;
 
 pub(crate) enum FileAttributeContext<'a> {
     Root(Option<DebugLineOffset>),
diff --git a/crates/debug/src/transform/expression.rs b/crates/debug/src/transform/expression.rs
index 64950a303c..6da8818e55 100644
--- a/crates/debug/src/transform/expression.rs
+++ b/crates/debug/src/transform/expression.rs
@@ -1,6 +1,4 @@
 use super::address_transform::AddressTransform;
-use crate::{HashMap, HashSet};
-use alloc::vec::Vec;
 use anyhow::Error;
 use cranelift_codegen::ir::{StackSlots, ValueLabel, ValueLoc};
 use cranelift_codegen::isa::RegUnit;
@@ -9,6 +7,7 @@ use cranelift_entity::EntityRef;
 use cranelift_wasm::{get_vmctx_value_label, DefinedFuncIndex};
 use gimli::{self, write, Expression, Operation, Reader, ReaderOffset, Register, X86_64};
 use more_asserts::{assert_le, assert_lt};
+use std::collections::{HashMap, HashSet};
 
 #[derive(Debug)]
 pub struct FunctionFrameInfo<'a> {
@@ -201,7 +200,7 @@ impl CompiledExpression {
         addr_tr: &AddressTransform,
         frame_info: Option<&FunctionFrameInfo>,
         endian: gimli::RunTimeEndian,
-    ) -> alloc::vec::Vec<(write::Address, u64, write::Expression)> {
+    ) -> Vec<(write::Address, u64, write::Expression)> {
         if scope.is_empty() {
             return vec![];
         }
diff --git a/crates/debug/src/transform/line_program.rs b/crates/debug/src/transform/line_program.rs
index 7d6deaaeba..d9e1434136 100644
--- a/crates/debug/src/transform/line_program.rs
+++ b/crates/debug/src/transform/line_program.rs
@@ -1,15 +1,14 @@
 use super::address_transform::AddressTransform;
 use super::attr::clone_attr_string;
 use super::{Reader, TransformError};
-use alloc::collections::BTreeMap;
-use alloc::vec::Vec;
 use anyhow::Error;
-use core::iter::FromIterator;
 use cranelift_entity::EntityRef;
 use gimli::{
     write, DebugLine, DebugLineOffset, DebugStr, DebuggingInformationEntry, LineEncoding, Unit,
 };
 use more_asserts::assert_le;
+use std::collections::BTreeMap;
+use std::iter::FromIterator;
 
 #[derive(Debug)]
 enum SavedLineProgramRow {
diff --git a/crates/debug/src/transform/mod.rs b/crates/debug/src/transform/mod.rs
index 18dd363a52..65dc055b8b 100644
--- a/crates/debug/src/transform/mod.rs
+++ b/crates/debug/src/transform/mod.rs
@@ -1,5 +1,5 @@
 use crate::gc::build_dependencies;
-use crate::{DebugInfoData, HashSet};
+use crate::DebugInfoData;
 use anyhow::Error;
 use cranelift_codegen::isa::TargetFrontendConfig;
 use gimli::{
@@ -7,6 +7,7 @@ use gimli::{
     UnitSectionOffset,
 };
 use simulate::generate_simulated_dwarf;
+use std::collections::HashSet;
 use thiserror::Error;
 use unit::clone_unit;
 use wasmtime_environ::{ModuleAddressMap, ModuleVmctxInfo, ValueLabelsRanges};
diff --git a/crates/debug/src/transform/range_info_builder.rs b/crates/debug/src/transform/range_info_builder.rs
index e26b1e451e..d9077fa3e8 100644
--- a/crates/debug/src/transform/range_info_builder.rs
+++ b/crates/debug/src/transform/range_info_builder.rs
@@ -1,6 +1,5 @@
 use super::address_transform::AddressTransform;
 use super::{DebugInputContext, Reader};
-use alloc::vec::Vec;
 use anyhow::Error;
 use cranelift_entity::EntityRef;
 use cranelift_wasm::DefinedFuncIndex;
diff --git a/crates/debug/src/transform/simulate.rs b/crates/debug/src/transform/simulate.rs
index 728a30ea94..197fe4cd58 100644
--- a/crates/debug/src/transform/simulate.rs
+++ b/crates/debug/src/transform/simulate.rs
@@ -2,14 +2,12 @@ use super::expression::{CompiledExpression, FunctionFrameInfo};
 use super::utils::{add_internal_types, append_vmctx_info, get_function_frame_info};
 use super::AddressTransform;
 use crate::read_debuginfo::WasmFileInfo;
-use crate::{HashMap, HashSet};
-use alloc::string::String;
-use alloc::vec::Vec;
 use anyhow::Error;
 use cranelift_entity::EntityRef;
 use cranelift_wasm::get_vmctx_value_label;
 use gimli::write;
 use gimli::{self, LineEncoding};
+use std::collections::{HashMap, HashSet};
 use std::path::PathBuf;
 use wasmtime_environ::{ModuleVmctxInfo, ValueLabelsRanges};
 
diff --git a/crates/debug/src/transform/unit.rs b/crates/debug/src/transform/unit.rs
index ee5d929892..64bd5f82be 100644
--- a/crates/debug/src/transform/unit.rs
+++ b/crates/debug/src/transform/unit.rs
@@ -5,12 +5,11 @@ use super::line_program::clone_line_program;
 use super::range_info_builder::RangeInfoBuilder;
 use super::utils::{add_internal_types, append_vmctx_info, get_function_frame_info};
 use super::{DebugInputContext, Reader, TransformError};
-use crate::{HashMap, HashSet};
-use alloc::{string::String, vec::Vec};
 use anyhow::Error;
 use cranelift_entity::EntityRef;
 use gimli::write;
 use gimli::{AttributeValue, DebuggingInformationEntry, Unit, UnitOffset};
+use std::collections::{HashMap, HashSet};
 use wasmtime_environ::{ModuleVmctxInfo, ValueLabelsRanges};
 
 pub(crate) type PendingDieRef = (write::UnitEntryId, gimli::DwAt, UnitOffset);
diff --git a/crates/debug/src/transform/utils.rs b/crates/debug/src/transform/utils.rs
index 24c94df265..4fca0d0837 100644
--- a/crates/debug/src/transform/utils.rs
+++ b/crates/debug/src/transform/utils.rs
@@ -1,6 +1,5 @@
 use super::address_transform::AddressTransform;
 use super::expression::{CompiledExpression, FunctionFrameInfo};
-use alloc::vec::Vec;
 use anyhow::Error;
 use cranelift_wasm::DefinedFuncIndex;
 use gimli::write;
diff --git a/crates/debug/src/write_debuginfo.rs b/crates/debug/src/write_debuginfo.rs
index 3e0b6e1d3c..28771ab3e3 100644
--- a/crates/debug/src/write_debuginfo.rs
+++ b/crates/debug/src/write_debuginfo.rs
@@ -1,8 +1,8 @@
-use alloc::{string::String, vec::Vec};
 use faerie::artifact::{Decl, SectionKind};
 use faerie::*;
 use gimli::write::{Address, Dwarf, EndianVec, Result, Sections, Writer};
 use gimli::{RunTimeEndian, SectionId};
+use std::result;
 
 #[derive(Clone)]
 struct DebugReloc {
diff --git a/crates/environ/Cargo.toml b/crates/environ/Cargo.toml
index ff2ebe1d33..97cd656cec 100644
--- a/crates/environ/Cargo.toml
+++ b/crates/environ/Cargo.toml
@@ -48,10 +48,5 @@ rand = { version = "0.7.0", features = ["small_rng"] }
 cranelift-codegen = { version = "0.50.0", features = ["enable-serde", "all-arch"] }
 filetime = "0.2.7"
 
-[features]
-default = ["std"]
-std = ["cranelift-codegen/std", "cranelift-wasm/std"]
-core = ["cranelift-codegen/core", "cranelift-wasm/core"]
-
 [badges]
 maintenance = { status = "actively-developed" }
diff --git a/crates/environ/src/address_map.rs b/crates/environ/src/address_map.rs
index b3aeafa997..3ca12abebb 100644
--- a/crates/environ/src/address_map.rs
+++ b/crates/environ/src/address_map.rs
@@ -1,7 +1,6 @@
 //! Data structures to provide transformation of the source
 // addresses of a WebAssembly module into the native code.
 
-use alloc::vec::Vec;
 use cranelift_codegen::ir;
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::DefinedFuncIndex;
diff --git a/crates/environ/src/cache.rs b/crates/environ/src/cache.rs
index 2d65dc298b..dad5f490b4 100644
--- a/crates/environ/src/cache.rs
+++ b/crates/environ/src/cache.rs
@@ -2,8 +2,6 @@ use crate::address_map::{ModuleAddressMap, ValueLabelsRanges};
 use crate::compilation::{Compilation, Relocations, Traps};
 use crate::module::Module;
 use crate::module_environ::FunctionBodyData;
-use alloc::string::{String, ToString};
-use core::hash::Hasher;
 use cranelift_codegen::{ir, isa};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::DefinedFuncIndex;
@@ -12,6 +10,7 @@ use log::{debug, trace, warn};
 use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
 use std::fs;
+use std::hash::Hasher;
 use std::io::Write;
 use std::path::{Path, PathBuf};
 
diff --git a/crates/environ/src/cache/config.rs b/crates/environ/src/cache/config.rs
index e625f37248..bf128e1070 100644
--- a/crates/environ/src/cache/config.rs
+++ b/crates/environ/src/cache/config.rs
@@ -1,9 +1,6 @@
 //! Module for configuring the cache system.
 
 use super::worker;
-use alloc::string::{String, ToString};
-use alloc::vec::Vec;
-use core::time::Duration;
 use directories::ProjectDirs;
 use lazy_static::lazy_static;
 use log::{debug, error, trace, warn};
@@ -17,6 +14,7 @@ use std::fs;
 use std::mem;
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::time::Duration;
 
 // wrapped, so we have named section in config,
 // also, for possible future compatibility
diff --git a/crates/environ/src/cache/config/tests.rs b/crates/environ/src/cache/config/tests.rs
index 33c252611f..7a9094a2ad 100644
--- a/crates/environ/src/cache/config/tests.rs
+++ b/crates/environ/src/cache/config/tests.rs
@@ -1,7 +1,7 @@
 use super::CacheConfig;
-use core::time::Duration;
 use std::fs;
 use std::path::PathBuf;
+use std::time::Duration;
 use tempfile::{self, TempDir};
 
 // note: config loading during validation creates cache directory to canonicalize its path,
diff --git a/crates/environ/src/cache/tests.rs b/crates/environ/src/cache/tests.rs
index 7e9632da89..55685d6de7 100644
--- a/crates/environ/src/cache/tests.rs
+++ b/crates/environ/src/cache/tests.rs
@@ -3,15 +3,13 @@ use super::*;
 use crate::address_map::{FunctionAddressMap, InstructionAddressMap};
 use crate::compilation::{CompiledFunction, Relocation, RelocationTarget, TrapInformation};
 use crate::module::{MemoryPlan, MemoryStyle, Module};
-use alloc::boxed::Box;
-use alloc::vec::Vec;
-use core::cmp::min;
 use cranelift_codegen::{binemit, ir, isa, settings, ValueLocRange};
 use cranelift_entity::EntityRef;
 use cranelift_entity::{PrimaryMap, SecondaryMap};
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex, Global, GlobalInit, Memory, SignatureIndex};
 use rand::rngs::SmallRng;
 use rand::{Rng, SeedableRng};
+use std::cmp::min;
 use std::fs;
 use std::str::FromStr;
 use target_lexicon::triple;
diff --git a/crates/environ/src/cache/worker.rs b/crates/environ/src/cache/worker.rs
index 673ea7694e..8f71390004 100644
--- a/crates/environ/src/cache/worker.rs
+++ b/crates/environ/src/cache/worker.rs
@@ -6,12 +6,10 @@
 //! Background tasks can be CPU intensive, but the worker thread has low priority.
 
 use super::{cache_config, fs_write_atomic, CacheConfig};
-use alloc::vec::Vec;
-use core::cmp;
-use core::time::Duration;
 use log::{debug, info, trace, warn};
 use serde::{Deserialize, Serialize};
 use spin::Once;
+use std::cmp;
 use std::collections::HashMap;
 use std::ffi::OsStr;
 use std::fs;
@@ -21,6 +19,7 @@ use std::sync::mpsc::{sync_channel, Receiver, SyncSender};
 #[cfg(test)]
 use std::sync::{Arc, Condvar, Mutex};
 use std::thread;
+use std::time::Duration;
 #[cfg(not(test))]
 use std::time::SystemTime;
 #[cfg(test)]
@@ -234,7 +233,7 @@ impl WorkerThread {
 
     #[cfg(target_os = "windows")]
     fn lower_thread_priority() {
-        use core::convert::TryInto;
+        use std::convert::TryInto;
         use winapi::um::processthreadsapi::{GetCurrentThread, SetThreadPriority};
         use winapi::um::winbase::THREAD_MODE_BACKGROUND_BEGIN;
 
diff --git a/crates/environ/src/cache/worker/tests.rs b/crates/environ/src/cache/worker/tests.rs
index 1eb7f5c549..43f0c0671a 100644
--- a/crates/environ/src/cache/worker/tests.rs
+++ b/crates/environ/src/cache/worker/tests.rs
@@ -1,7 +1,7 @@
 use super::*;
 use crate::cache::config::tests::test_prolog;
-use core::iter::repeat;
 use more_asserts::{assert_ge, assert_gt, assert_lt};
+use std::iter::repeat;
 use std::process;
 // load_config! comes from crate::cache(::config::tests);
 
diff --git a/crates/environ/src/compilation.rs b/crates/environ/src/compilation.rs
index c0da59ffbf..b386d456c8 100644
--- a/crates/environ/src/compilation.rs
+++ b/crates/environ/src/compilation.rs
@@ -4,7 +4,6 @@
 use crate::address_map::{ModuleAddressMap, ValueLabelsRanges};
 use crate::module;
 use crate::module_environ::FunctionBodyData;
-use alloc::vec::Vec;
 use cranelift_codegen::{binemit, ir, isa};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex, ModuleTranslationState, WasmError};
diff --git a/crates/environ/src/cranelift.rs b/crates/environ/src/cranelift.rs
index b48925f86b..f3d000e6d8 100644
--- a/crates/environ/src/cranelift.rs
+++ b/crates/environ/src/cranelift.rs
@@ -14,7 +14,6 @@ use crate::func_environ::{
 };
 use crate::module::Module;
 use crate::module_environ::FunctionBodyData;
-use alloc::vec::Vec;
 use cranelift_codegen::binemit;
 use cranelift_codegen::ir;
 use cranelift_codegen::ir::ExternalName;
diff --git a/crates/environ/src/func_environ.rs b/crates/environ/src/func_environ.rs
index a0da1c4acb..39eebe34cc 100644
--- a/crates/environ/src/func_environ.rs
+++ b/crates/environ/src/func_environ.rs
@@ -1,9 +1,6 @@
 use crate::module::{MemoryPlan, MemoryStyle, Module, TableStyle};
 use crate::vmoffsets::VMOffsets;
 use crate::WASM_PAGE_SIZE;
-use alloc::vec::Vec;
-use core::clone::Clone;
-use core::convert::TryFrom;
 use cranelift_codegen::cursor::FuncCursor;
 use cranelift_codegen::ir;
 use cranelift_codegen::ir::condcodes::*;
@@ -18,6 +15,7 @@ use cranelift_wasm::{
 };
 #[cfg(feature = "lightbeam")]
 use cranelift_wasm::{DefinedFuncIndex, DefinedGlobalIndex, DefinedMemoryIndex, DefinedTableIndex};
+use std::convert::TryFrom;
 
 /// Compute an `ir::ExternalName` for a given wasm function index.
 pub fn get_func_name(func_index: FuncIndex) -> ir::ExternalName {
diff --git a/crates/environ/src/lib.rs b/crates/environ/src/lib.rs
index d80809989b..5e23601c91 100644
--- a/crates/environ/src/lib.rs
+++ b/crates/environ/src/lib.rs
@@ -5,7 +5,6 @@
 
 #![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")))]
 #![cfg_attr(
     feature = "cargo-clippy",
@@ -25,8 +24,6 @@
     )
 )]
 
-extern crate alloc;
-
 mod address_map;
 mod compilation;
 mod func_environ;
diff --git a/crates/environ/src/module.rs b/crates/environ/src/module.rs
index f719df6aee..fefaf72dca 100644
--- a/crates/environ/src/module.rs
+++ b/crates/environ/src/module.rs
@@ -2,10 +2,6 @@
 
 use crate::module_environ::FunctionBodyData;
 use crate::tunables::Tunables;
-use alloc::boxed::Box;
-use alloc::string::String;
-use alloc::vec::Vec;
-use core::hash::{Hash, Hasher};
 use cranelift_codegen::ir;
 use cranelift_entity::{EntityRef, PrimaryMap};
 use cranelift_wasm::{
@@ -14,6 +10,7 @@ use cranelift_wasm::{
 };
 use indexmap::IndexMap;
 use more_asserts::assert_ge;
+use std::hash::{Hash, Hasher};
 
 /// A WebAssembly table initializer.
 #[derive(Clone, Debug, Hash)]
diff --git a/crates/environ/src/module_environ.rs b/crates/environ/src/module_environ.rs
index f5aa67062b..e84dd4b85f 100644
--- a/crates/environ/src/module_environ.rs
+++ b/crates/environ/src/module_environ.rs
@@ -1,10 +1,6 @@
 use crate::func_environ::FuncEnvironment;
 use crate::module::{Export, MemoryPlan, Module, TableElements, TablePlan};
 use crate::tunables::Tunables;
-use alloc::boxed::Box;
-use alloc::string::String;
-use alloc::vec::Vec;
-use core::convert::TryFrom;
 use cranelift_codegen::ir;
 use cranelift_codegen::ir::{AbiParam, ArgumentPurpose};
 use cranelift_codegen::isa::TargetFrontendConfig;
@@ -13,6 +9,7 @@ use cranelift_wasm::{
     self, translate_module, DefinedFuncIndex, FuncIndex, Global, GlobalIndex, Memory, MemoryIndex,
     ModuleTranslationState, SignatureIndex, Table, TableIndex, WasmResult,
 };
+use std::convert::TryFrom;
 
 /// Contains function data: byte code and its offset in the module.
 #[derive(Hash)]
diff --git a/crates/environ/src/vmoffsets.rs b/crates/environ/src/vmoffsets.rs
index e0659b47ed..615247ed78 100644
--- a/crates/environ/src/vmoffsets.rs
+++ b/crates/environ/src/vmoffsets.rs
@@ -3,13 +3,13 @@
 
 use crate::module::Module;
 use crate::BuiltinFunctionIndex;
-use core::convert::TryFrom;
 use cranelift_codegen::ir;
 use cranelift_wasm::{
     DefinedGlobalIndex, DefinedMemoryIndex, DefinedTableIndex, FuncIndex, GlobalIndex, MemoryIndex,
     SignatureIndex, TableIndex,
 };
 use more_asserts::assert_lt;
+use std::convert::TryFrom;
 
 #[cfg(target_pointer_width = "32")]
 fn cast_to_u32(sz: usize) -> u32 {
diff --git a/crates/interface-types/Cargo.toml b/crates/interface-types/Cargo.toml
index cef0a95dc3..b94178016d 100644
--- a/crates/interface-types/Cargo.toml
+++ b/crates/interface-types/Cargo.toml
@@ -17,8 +17,8 @@ walrus = "0.13"
 wasmparser = { version = "0.39.2", default-features = false }
 wasm-webidl-bindings = "0.6"
 wasmtime = { path = '../api' }
-wasmtime-jit = { path = '../jit', default-features = false }
-wasmtime-runtime = { path = '../runtime', default-features = false }
+wasmtime-jit = { path = '../jit' }
+wasmtime-runtime = { path = '../runtime' }
 wasmtime-wasi = { path = '../wasi' }
 
 [badges]
diff --git a/crates/interface-types/src/lib.rs b/crates/interface-types/src/lib.rs
index 2ff18a200b..064c5d65cf 100644
--- a/crates/interface-types/src/lib.rs
+++ b/crates/interface-types/src/lib.rs
@@ -7,15 +7,10 @@
 
 #![deny(missing_docs)]
 
-extern crate alloc;
-
-use alloc::boxed::Box;
-use alloc::string::ToString;
-use alloc::vec::Vec;
 use anyhow::{bail, format_err, Result};
-use core::convert::TryFrom;
-use core::str;
 use cranelift_codegen::ir;
+use std::convert::TryFrom;
+use std::str;
 use wasm_webidl_bindings::ast;
 use wasmtime_api as api;
 use wasmtime_jit::RuntimeValue;
diff --git a/crates/interface-types/src/value.rs b/crates/interface-types/src/value.rs
index 50778cf1c6..84fc081196 100644
--- a/crates/interface-types/src/value.rs
+++ b/crates/interface-types/src/value.rs
@@ -1,6 +1,5 @@
-use alloc::string::{String, ToString};
-use core::convert::TryFrom;
-use core::fmt;
+use std::convert::TryFrom;
+use std::fmt;
 
 /// The set of all possible WebAssembly Interface Types
 #[derive(Debug, Clone)]
diff --git a/crates/jit/Cargo.toml b/crates/jit/Cargo.toml
index 21dfb718dc..3fc9e0c644 100644
--- a/crates/jit/Cargo.toml
+++ b/crates/jit/Cargo.toml
@@ -15,13 +15,12 @@ cranelift-codegen = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-entity = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-wasm = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-frontend = "0.50.0"
-wasmtime-environ = { path = "../environ", default-features = false }
-wasmtime-runtime = { path = "../runtime", default-features = false }
-wasmtime-debug = { path = "../debug", default-features = false }
+wasmtime-environ = { path = "../environ" }
+wasmtime-runtime = { path = "../runtime" }
+wasmtime-debug = { path = "../debug" }
 region = "2.0.0"
 thiserror = "1.0.4"
 target-lexicon = { version = "0.9.0", default-features = false }
-hashbrown = { version = "0.6.0", optional = true }
 wasmparser = { version = "0.39.2", default-features = false }
 more-asserts = "0.2.1"
 anyhow = "1.0"
@@ -30,23 +29,6 @@ anyhow = "1.0"
 winapi = { version = "0.3.7", features = ["winnt", "impl-default"] }
 
 [features]
-default = ["std"]
-std = [
-    "cranelift-codegen/std",
-    "cranelift-wasm/std",
-    "wasmtime-environ/std",
-    "wasmtime-debug/std",
-    "wasmtime-runtime/std",
-    "wasmparser/std"
-]
-core = [
-    "hashbrown/nightly",
-    "cranelift-codegen/core",
-    "cranelift-wasm/core",
-    "wasmtime-environ/core",
-    "wasmtime-debug/core",
-    "wasmparser/core"
-]
 lightbeam = ["wasmtime-environ/lightbeam"]
 
 [badges]
diff --git a/crates/jit/src/action.rs b/crates/jit/src/action.rs
index a09357af1c..0c1be9d942 100644
--- a/crates/jit/src/action.rs
+++ b/crates/jit/src/action.rs
@@ -2,11 +2,9 @@
 
 use crate::compiler::Compiler;
 use crate::instantiate::SetupError;
-use alloc::string::String;
-use alloc::vec::Vec;
-use core::cmp::max;
-use core::{fmt, mem, ptr, slice};
 use cranelift_codegen::ir;
+use std::cmp::max;
+use std::{fmt, mem, ptr, slice};
 use thiserror::Error;
 use wasmtime_runtime::{wasmtime_call_trampoline, Export, InstanceHandle, VMInvokeArgument};
 
diff --git a/crates/jit/src/code_memory.rs b/crates/jit/src/code_memory.rs
index e11c66fadf..c1db466f80 100644
--- a/crates/jit/src/code_memory.rs
+++ b/crates/jit/src/code_memory.rs
@@ -1,11 +1,8 @@
 //! Memory management for executable code.
 
 use crate::function_table::FunctionTable;
-use alloc::boxed::Box;
-use alloc::string::String;
-use alloc::vec::Vec;
-use core::{cmp, mem};
 use region;
+use std::{cmp, mem};
 use wasmtime_environ::{Compilation, CompiledFunction};
 use wasmtime_runtime::{Mmap, VMFunctionBody};
 
diff --git a/crates/jit/src/compiler.rs b/crates/jit/src/compiler.rs
index cbe25f219d..4020baf650 100644
--- a/crates/jit/src/compiler.rs
+++ b/crates/jit/src/compiler.rs
@@ -1,13 +1,8 @@
 //! JIT compilation.
 
-use super::HashMap;
 use crate::code_memory::CodeMemory;
 use crate::instantiate::SetupError;
 use crate::target_tunables::target_tunables;
-use alloc::boxed::Box;
-use alloc::string::String;
-use alloc::vec::Vec;
-use core::convert::TryFrom;
 use cranelift_codegen::ir::InstBuilder;
 use cranelift_codegen::isa::{TargetFrontendConfig, TargetIsa};
 use cranelift_codegen::print_errors::pretty_error;
@@ -16,6 +11,8 @@ use cranelift_codegen::{binemit, ir};
 use cranelift_entity::{EntityRef, PrimaryMap};
 use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
 use cranelift_wasm::{DefinedFuncIndex, DefinedMemoryIndex, ModuleTranslationState};
+use std::collections::HashMap;
+use std::convert::TryFrom;
 use wasmtime_debug::{emit_debugsections_image, DebugInfoData};
 use wasmtime_environ::{
     Compilation, CompileError, CompiledFunction, Compiler as _C, FunctionBodyData, Module,
@@ -202,7 +199,7 @@ impl Compiler {
         signature: &ir::Signature,
         value_size: usize,
     ) -> Result<*const VMFunctionBody, SetupError> {
-        use super::hash_map::Entry::{Occupied, Vacant};
+        use std::collections::hash_map::Entry::{Occupied, Vacant};
         Ok(match self.trampoline_park.entry(callee_address) {
             Occupied(entry) => *entry.get(),
             Vacant(entry) => {
diff --git a/crates/jit/src/context.rs b/crates/jit/src/context.rs
index 77b3e2e52f..e835110b09 100644
--- a/crates/jit/src/context.rs
+++ b/crates/jit/src/context.rs
@@ -1,14 +1,12 @@
 use crate::action::{get, inspect_memory, invoke};
-use crate::HashMap;
 use crate::{
     instantiate, ActionError, ActionOutcome, CompilationStrategy, CompiledModule, Compiler,
     InstanceHandle, Namespace, RuntimeValue, SetupError,
 };
-use alloc::boxed::Box;
-use alloc::rc::Rc;
-use alloc::string::{String, ToString};
-use core::cell::RefCell;
 use cranelift_codegen::isa::TargetIsa;
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::rc::Rc;
 use thiserror::Error;
 use wasmparser::{validate, OperatorValidatorConfig, ValidatingParserConfig};
 
diff --git a/crates/jit/src/instantiate.rs b/crates/jit/src/instantiate.rs
index edd35a9ef5..34240e942c 100644
--- a/crates/jit/src/instantiate.rs
+++ b/crates/jit/src/instantiate.rs
@@ -3,19 +3,15 @@
 //! `CompiledModule` to allow compiling and instantiating to be done as separate
 //! steps.
 
-use super::HashMap;
 use crate::compiler::Compiler;
 use crate::link::link_module;
 use crate::resolver::Resolver;
-use alloc::boxed::Box;
-use alloc::rc::Rc;
-use alloc::string::String;
-use alloc::vec::Vec;
-use core::cell::RefCell;
 use cranelift_entity::{BoxedSlice, PrimaryMap};
 use cranelift_wasm::{DefinedFuncIndex, SignatureIndex};
-#[cfg(feature = "std")]
+use std::cell::RefCell;
+use std::collections::HashMap;
 use std::io::Write;
+use std::rc::Rc;
 use thiserror::Error;
 use wasmtime_debug::read_debuginfo;
 use wasmtime_environ::{
@@ -120,7 +116,6 @@ impl<'data> RawCompiledModule<'data> {
         // Make all code compiled thus far executable.
         compiler.publish_compiled_code();
 
-        #[cfg(feature = "std")]
         let dbg_jit_registration = if let Some(img) = dbg_image {
             let mut bytes = Vec::new();
             bytes.write_all(&img).expect("all written");
diff --git a/crates/jit/src/lib.rs b/crates/jit/src/lib.rs
index e906fa862f..2405180254 100644
--- a/crates/jit/src/lib.rs
+++ b/crates/jit/src/lib.rs
@@ -2,7 +2,6 @@
 
 #![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")))]
 #![cfg_attr(
     feature = "cargo-clippy",
@@ -22,13 +21,6 @@
     )
 )]
 
-extern crate alloc;
-
-#[cfg(not(feature = "std"))]
-use hashbrown::{hash_map, HashMap, HashSet};
-#[cfg(feature = "std")]
-use std::collections::{hash_map, HashMap, HashSet};
-
 mod action;
 mod code_memory;
 mod compiler;
diff --git a/crates/jit/src/link.rs b/crates/jit/src/link.rs
index fb43a07e2c..44369b9286 100644
--- a/crates/jit/src/link.rs
+++ b/crates/jit/src/link.rs
@@ -1,14 +1,13 @@
 //! Linking for JIT-compiled code.
 
 use crate::resolver::Resolver;
-use crate::HashSet;
-use alloc::vec::Vec;
-use core::ptr::write_unaligned;
 use cranelift_codegen::binemit::Reloc;
 use cranelift_codegen::ir::JumpTableOffsets;
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::{DefinedFuncIndex, Global, GlobalInit, Memory, Table, TableElementType};
 use more_asserts::assert_ge;
+use std::collections::HashSet;
+use std::ptr::write_unaligned;
 use wasmtime_environ::{
     MemoryPlan, MemoryStyle, Module, Relocation, RelocationTarget, Relocations, TablePlan,
 };
diff --git a/crates/jit/src/namespace.rs b/crates/jit/src/namespace.rs
index acddc6da10..dc2c0a9e1f 100644
--- a/crates/jit/src/namespace.rs
+++ b/crates/jit/src/namespace.rs
@@ -2,9 +2,8 @@
 //! to exports. This file provides one possible way to manage multiple instances
 //! and resolve imports to exports among them.
 
-use super::HashMap;
 use crate::resolver::Resolver;
-use alloc::string::String;
+use std::collections::HashMap;
 use wasmtime_runtime::{Export, InstanceHandle};
 
 /// A namespace containing instances keyed by name.
diff --git a/crates/jit/src/target_tunables.rs b/crates/jit/src/target_tunables.rs
index dfeac9fbc7..2fd5b4848f 100644
--- a/crates/jit/src/target_tunables.rs
+++ b/crates/jit/src/target_tunables.rs
@@ -1,4 +1,4 @@
-use core::cmp::min;
+use std::cmp::min;
 use target_lexicon::{OperatingSystem, Triple};
 use wasmtime_environ::Tunables;
 
diff --git a/crates/lightbeam/src/function_body.rs b/crates/lightbeam/src/function_body.rs
index 740cf79c8f..9c29676035 100644
--- a/crates/lightbeam/src/function_body.rs
+++ b/crates/lightbeam/src/function_body.rs
@@ -5,13 +5,13 @@ use crate::backend::{
 use crate::error::Error;
 use crate::microwasm::*;
 use crate::module::{ModuleContext, SigType, Signature};
-use core::{fmt, mem};
 use cranelift_codegen::binemit;
 use dynasmrt::DynasmApi;
 use either::{Either, Left, Right};
 use more_asserts::assert_ge;
 use multi_mut::HashMapMultiMut;
 use std::{collections::HashMap, hash::Hash};
+use std::{fmt, mem};
 
 #[derive(Debug)]
 struct Block {
diff --git a/crates/lightbeam/src/module.rs b/crates/lightbeam/src/module.rs
index 61636e8f02..a2f7f9922c 100644
--- a/crates/lightbeam/src/module.rs
+++ b/crates/lightbeam/src/module.rs
@@ -2,13 +2,13 @@ use crate::backend::TranslatedCodeSection;
 use crate::error::Error;
 use crate::microwasm;
 use crate::translate_sections;
-use core::{convert::TryInto, mem};
 use cranelift_codegen::{
     ir::{self, AbiParam, Signature as CraneliftSignature},
     isa,
 };
 use memoffset::offset_of;
 use more_asserts::assert_le;
+use std::{convert::TryInto, mem};
 use thiserror::Error;
 use wasmparser::{FuncType, MemoryType, ModuleReader, SectionCode, Type};
 
@@ -167,7 +167,7 @@ impl ExecutableModule {
             self.context
                 .as_ref()
                 .map(|ctx| (&**ctx) as *const VmCtx as *const u8)
-                .unwrap_or(core::ptr::null()),
+                .unwrap_or(std::ptr::null()),
         )
     }
 
diff --git a/crates/misc/py/src/function.rs b/crates/misc/py/src/function.rs
index 856377f7ef..3cdebbdec7 100644
--- a/crates/misc/py/src/function.rs
+++ b/crates/misc/py/src/function.rs
@@ -1,12 +1,10 @@
 //! Support for a calling of a bounds (exported) function.
 
-extern crate alloc;
-
 use crate::value::{pyobj_to_value, value_to_pyobj};
-use alloc::rc::Rc;
 use pyo3::exceptions::Exception;
 use pyo3::prelude::*;
 use pyo3::types::{PyAny, PyDict, PyTuple};
+use std::rc::Rc;
 use wasmtime_api as api;
 use wasmtime_interface_types::ModuleData;
 
diff --git a/crates/misc/py/src/instance.rs b/crates/misc/py/src/instance.rs
index e789edec10..62c602daae 100644
--- a/crates/misc/py/src/instance.rs
+++ b/crates/misc/py/src/instance.rs
@@ -1,12 +1,10 @@
 //! WebAssembly Instance API object.
 
-extern crate alloc;
-
 use crate::function::Function;
 use crate::memory::Memory;
-use alloc::rc::Rc;
 use pyo3::prelude::*;
 use pyo3::types::PyDict;
+use std::rc::Rc;
 use wasmtime_api as api;
 use wasmtime_interface_types::ModuleData;
 
diff --git a/crates/misc/py/src/memory.rs b/crates/misc/py/src/memory.rs
index 8dc161c162..cb603c836d 100644
--- a/crates/misc/py/src/memory.rs
+++ b/crates/misc/py/src/memory.rs
@@ -1,14 +1,12 @@
 //! WebAssembly Memory API object.
 
-extern crate alloc;
-
-use core::ptr;
 use pyo3::class::PyBufferProtocol;
 use pyo3::exceptions::BufferError;
 use pyo3::ffi;
 use pyo3::prelude::*;
 use std::ffi::CStr;
 use std::os::raw::{c_int, c_void};
+use std::ptr;
 use wasmtime_api as api;
 
 #[pyclass]
diff --git a/crates/misc/py/src/module.rs b/crates/misc/py/src/module.rs
index 87aa10f6ac..ead54fecd6 100644
--- a/crates/misc/py/src/module.rs
+++ b/crates/misc/py/src/module.rs
@@ -1,7 +1,5 @@
 //! WebAssembly Module API object.
 
-extern crate alloc;
-
 use pyo3::prelude::*;
 use wasmtime_api as api;
 
diff --git a/crates/obj/src/context.rs b/crates/obj/src/context.rs
index f97604c7b5..5ee980f77d 100644
--- a/crates/obj/src/context.rs
+++ b/crates/obj/src/context.rs
@@ -1,14 +1,12 @@
 #![allow(clippy::cast_ptr_alignment)]
 
-use alloc::boxed::Box;
-use alloc::vec::Vec;
-use core::ptr;
 use cranelift_codegen::isa::TargetFrontendConfig;
 use cranelift_entity::EntityRef;
 use cranelift_wasm::GlobalInit;
 use more_asserts::assert_le;
 use std::collections::hash_map::Entry;
 use std::collections::HashMap;
+use std::ptr;
 use wasmtime_environ::{Module, TargetSharedSignatureIndex, VMOffsets};
 
 pub struct TableRelocation {
@@ -32,7 +30,7 @@ pub fn layout_vmcontext(
         let target_index = match signature_registry.entry(sig) {
             Entry::Occupied(o) => *o.get(),
             Entry::Vacant(v) => {
-                assert_le!(signature_registry_len, ::core::u32::MAX as usize);
+                assert_le!(signature_registry_len, std::u32::MAX as usize);
                 let id = TargetSharedSignatureIndex::new(signature_registry_len as u32);
                 signature_registry_len += 1;
                 *v.insert(id)
diff --git a/crates/obj/src/data_segment.rs b/crates/obj/src/data_segment.rs
index 6554c9c245..c4ce8862cd 100644
--- a/crates/obj/src/data_segment.rs
+++ b/crates/obj/src/data_segment.rs
@@ -1,5 +1,3 @@
-use alloc::string::String;
-use alloc::vec::Vec;
 use faerie::{Artifact, Decl};
 use wasmtime_environ::DataInitializer;
 
diff --git a/crates/obj/src/function.rs b/crates/obj/src/function.rs
index 45f2e95dac..59d3fcf049 100644
--- a/crates/obj/src/function.rs
+++ b/crates/obj/src/function.rs
@@ -1,4 +1,3 @@
-use alloc::string::String;
 use cranelift_codegen::settings;
 use cranelift_codegen::settings::Configurable;
 use cranelift_entity::EntityRef;
diff --git a/crates/obj/src/lib.rs b/crates/obj/src/lib.rs
index a95af9e66a..f4d9dc2d00 100644
--- a/crates/obj/src/lib.rs
+++ b/crates/obj/src/lib.rs
@@ -26,8 +26,6 @@
     )
 )]
 
-extern crate alloc;
-
 mod context;
 mod data_segment;
 mod function;
diff --git a/crates/obj/src/module.rs b/crates/obj/src/module.rs
index 23fbf0b07b..d35e652251 100644
--- a/crates/obj/src/module.rs
+++ b/crates/obj/src/module.rs
@@ -2,7 +2,6 @@ use crate::context::layout_vmcontext;
 use crate::data_segment::{declare_data_segment, emit_data_segment};
 use crate::function::{declare_functions, emit_functions};
 use crate::table::{declare_table, emit_table};
-use alloc::string::String;
 use cranelift_codegen::isa::TargetFrontendConfig;
 use faerie::{Artifact, Decl, Link};
 use wasmtime_environ::{Compilation, DataInitializer, Module, Relocations};
diff --git a/crates/obj/src/table.rs b/crates/obj/src/table.rs
index 0fced2d5c8..269e50927c 100644
--- a/crates/obj/src/table.rs
+++ b/crates/obj/src/table.rs
@@ -1,5 +1,3 @@
-use alloc::string::String;
-use alloc::vec::Vec;
 use faerie::{Artifact, Decl};
 
 /// Declares data segment symbol
diff --git a/crates/runtime/Cargo.toml b/crates/runtime/Cargo.toml
index 9b6409360a..8bf93483f1 100644
--- a/crates/runtime/Cargo.toml
+++ b/crates/runtime/Cargo.toml
@@ -14,14 +14,12 @@ edition = "2018"
 cranelift-codegen = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-entity = { version = "0.50.0", features = ["enable-serde"] }
 cranelift-wasm = { version = "0.50.0", features = ["enable-serde"] }
-wasmtime-environ = { path = "../environ", default-features = false }
+wasmtime-environ = { path = "../environ" }
 region = "2.0.0"
 lazy_static = "1.2.0"
 libc = { version = "0.2.60", default-features = false }
 memoffset = "0.5.3"
 indexmap = "1.0.2"
-hashbrown = { version = "0.6.0", optional = true }
-spin = { version = "0.5.2", optional = true }
 thiserror = "1.0.4"
 more-asserts = "0.2.1"
 
@@ -31,16 +29,5 @@ winapi = { version = "0.3.7", features = ["winbase", "memoryapi"] }
 [build-dependencies]
 cc = "1.0"
 
-[features]
-default = ["std"]
-std = ["cranelift-codegen/std", "cranelift-wasm/std", "wasmtime-environ/std"]
-core = [
-    "hashbrown/nightly",
-    "cranelift-codegen/core",
-    "cranelift-wasm/core",
-    "wasmtime-environ/core",
-    "spin"
-]
-
 [badges]
 maintenance = { status = "actively-developed" }
diff --git a/crates/runtime/src/imports.rs b/crates/runtime/src/imports.rs
index 3e670eb2cc..082f799ae6 100644
--- a/crates/runtime/src/imports.rs
+++ b/crates/runtime/src/imports.rs
@@ -1,8 +1,8 @@
 use crate::instance::InstanceHandle;
 use crate::vmcontext::{VMFunctionImport, VMGlobalImport, VMMemoryImport, VMTableImport};
-use crate::HashSet;
 use cranelift_entity::{BoxedSlice, PrimaryMap};
 use cranelift_wasm::{FuncIndex, GlobalIndex, MemoryIndex, TableIndex};
+use std::collections::HashSet;
 
 /// Resolved import pointers.
 #[derive(Clone)]
diff --git a/crates/runtime/src/instance.rs b/crates/runtime/src/instance.rs
index 49fbeb5c0a..95c22a7e27 100644
--- a/crates/runtime/src/instance.rs
+++ b/crates/runtime/src/instance.rs
@@ -15,16 +15,6 @@ use crate::vmcontext::{
     VMGlobalDefinition, VMGlobalImport, VMMemoryDefinition, VMMemoryImport, VMSharedSignatureIndex,
     VMTableDefinition, VMTableImport,
 };
-use crate::{HashMap, HashSet};
-use alloc::borrow::ToOwned;
-use alloc::boxed::Box;
-use alloc::rc::Rc;
-use alloc::string::{String, ToString};
-use core::any::Any;
-use core::borrow::Borrow;
-use core::cell::RefCell;
-use core::convert::TryFrom;
-use core::{mem, ptr, slice};
 use cranelift_entity::{BoxedSlice, EntityRef, PrimaryMap};
 use cranelift_wasm::{
     DefinedFuncIndex, DefinedGlobalIndex, DefinedMemoryIndex, DefinedTableIndex, FuncIndex,
@@ -32,6 +22,13 @@ use cranelift_wasm::{
 };
 use memoffset::offset_of;
 use more_asserts::assert_lt;
+use std::any::Any;
+use std::borrow::Borrow;
+use std::cell::RefCell;
+use std::collections::{HashMap, HashSet};
+use std::convert::TryFrom;
+use std::rc::Rc;
+use std::{mem, ptr, slice};
 use thiserror::Error;
 use wasmtime_environ::{DataInitializer, Module, TableElements, VMOffsets};
 
@@ -613,10 +610,8 @@ impl Instance {
     }
 
     pub(crate) fn lookup_global_export(&self, field: &str) -> Option<Export> {
-        let cell: &RefCell<HashMap<alloc::string::String, core::option::Option<Export>>> =
-            self.global_exports.borrow();
-        let map: &mut HashMap<alloc::string::String, core::option::Option<Export>> =
-            &mut cell.borrow_mut();
+        let cell: &RefCell<HashMap<String, Option<Export>>> = self.global_exports.borrow();
+        let map: &mut HashMap<String, Option<Export>> = &mut cell.borrow_mut();
         if let Some(Some(export)) = map.get(field) {
             return Some(export.clone());
         }
@@ -790,11 +785,9 @@ impl InstanceHandle {
 
         // Collect the exports for the global export map.
         for (field, decl) in &instance.module.exports {
-            use crate::hash_map::Entry::*;
-            let cell: &RefCell<HashMap<alloc::string::String, core::option::Option<Export>>> =
-                instance.global_exports.borrow();
-            let map: &mut HashMap<alloc::string::String, core::option::Option<Export>> =
-                &mut cell.borrow_mut();
+            use std::collections::hash_map::Entry::*;
+            let cell: &RefCell<HashMap<String, Option<Export>>> = instance.global_exports.borrow();
+            let map: &mut HashMap<String, Option<Export>> = &mut cell.borrow_mut();
             match map.entry(field.to_string()) {
                 Vacant(entry) => {
                     entry.insert(Some(lookup_by_declaration(
diff --git a/crates/runtime/src/jit_int.rs b/crates/runtime/src/jit_int.rs
index eed8cfda66..a8a0a44d6f 100644
--- a/crates/runtime/src/jit_int.rs
+++ b/crates/runtime/src/jit_int.rs
@@ -2,9 +2,7 @@
 //! the __jit_debug_register_code() and __jit_debug_descriptor to register
 //! or unregister generated object images with debuggers.
 
-use alloc::boxed::Box;
-use alloc::vec::Vec;
-use core::ptr;
+use std::ptr;
 
 #[repr(C)]
 struct JITCodeEntry {
@@ -41,7 +39,7 @@ extern "C" fn __jit_debug_register_code() {
     // Hack to not allow inlining even when Rust wants to do it in release mode.
     let x = 3;
     unsafe {
-        core::ptr::read_volatile(&x);
+        std::ptr::read_volatile(&x);
     }
 }
 
diff --git a/crates/runtime/src/lib.rs b/crates/runtime/src/lib.rs
index 12e79a7153..4a1f06d66c 100644
--- a/crates/runtime/src/lib.rs
+++ b/crates/runtime/src/lib.rs
@@ -3,7 +3,6 @@
 #![allow(improper_ctypes)]
 #![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")))]
 #![cfg_attr(
     feature = "cargo-clippy",
@@ -22,9 +21,6 @@
         clippy::use_self
     )
 )]
-#![cfg_attr(not(feature = "std"), no_std)]
-
-extern crate alloc;
 
 mod export;
 mod imports;
@@ -56,15 +52,5 @@ pub use crate::vmcontext::{
     VMTableDefinition, VMTableImport,
 };
 
-#[cfg(not(feature = "std"))]
-use hashbrown::{hash_map, HashMap, HashSet};
-#[cfg(feature = "std")]
-use std::collections::{hash_map, HashMap, HashSet};
-
-#[cfg(not(feature = "std"))]
-use spin::{RwLock, RwLockReadGuard, RwLockWriteGuard};
-#[cfg(feature = "std")]
-use std::sync::{RwLock, RwLockReadGuard, RwLockWriteGuard};
-
 /// Version number of this crate.
 pub const VERSION: &str = env!("CARGO_PKG_VERSION");
diff --git a/crates/runtime/src/memory.rs b/crates/runtime/src/memory.rs
index 9d3b290647..2ea3bbebb5 100644
--- a/crates/runtime/src/memory.rs
+++ b/crates/runtime/src/memory.rs
@@ -4,9 +4,8 @@
 
 use crate::mmap::Mmap;
 use crate::vmcontext::VMMemoryDefinition;
-use alloc::string::String;
-use core::convert::TryFrom;
 use more_asserts::{assert_ge, assert_le};
+use std::convert::TryFrom;
 use wasmtime_environ::{MemoryPlan, MemoryStyle, WASM_MAX_PAGES, WASM_PAGE_SIZE};
 
 /// A linear memory instance.
diff --git a/crates/runtime/src/mmap.rs b/crates/runtime/src/mmap.rs
index af019950f7..32acabbd86 100644
--- a/crates/runtime/src/mmap.rs
+++ b/crates/runtime/src/mmap.rs
@@ -1,16 +1,14 @@
 //! Low-level abstraction for allocating and managing zero-filled pages
 //! of memory.
 
-use alloc::string::{String, ToString};
-use alloc::vec::Vec;
-use core::ptr;
-use core::slice;
 #[cfg(not(target_os = "windows"))]
 use libc;
 use more_asserts::assert_le;
 use more_asserts::assert_lt;
 use region;
 use std::io;
+use std::ptr;
+use std::slice;
 
 /// Round `size` up to the nearest multiple of `page_size`.
 fn round_up_to_page_size(size: usize, page_size: usize) -> usize {
diff --git a/crates/runtime/src/sig_registry.rs b/crates/runtime/src/sig_registry.rs
index c415332529..243417af86 100644
--- a/crates/runtime/src/sig_registry.rs
+++ b/crates/runtime/src/sig_registry.rs
@@ -2,10 +2,10 @@
 //! signature checking.
 
 use crate::vmcontext::VMSharedSignatureIndex;
-use crate::{hash_map, HashMap};
-use core::convert::TryFrom;
 use cranelift_codegen::ir;
 use more_asserts::{assert_lt, debug_assert_lt};
+use std::collections::{hash_map, HashMap};
+use std::convert::TryFrom;
 
 /// WebAssembly requires that the caller and callee signatures in an indirect
 /// call must match. To implement this efficiently, keep a registry of all
@@ -30,12 +30,12 @@ impl SignatureRegistry {
         match self.signature_hash.entry(sig.clone()) {
             hash_map::Entry::Occupied(entry) => *entry.get(),
             hash_map::Entry::Vacant(entry) => {
-                // Keep `signature_hash` len under 2**32 -- VMSharedSignatureIndex::new(core::u32::MAX)
+                // Keep `signature_hash` len under 2**32 -- VMSharedSignatureIndex::new(std::u32::MAX)
                 // is reserved for VMSharedSignatureIndex::default().
                 debug_assert_lt!(
                     len,
-                    core::u32::MAX as usize,
-                    "Invariant check: signature_hash.len() < core::u32::MAX"
+                    std::u32::MAX as usize,
+                    "Invariant check: signature_hash.len() < std::u32::MAX"
                 );
                 let sig_id = VMSharedSignatureIndex::new(u32::try_from(len).unwrap());
                 entry.insert(sig_id);
diff --git a/crates/runtime/src/signalhandlers.rs b/crates/runtime/src/signalhandlers.rs
index 6c63ed6cb7..5beb737769 100644
--- a/crates/runtime/src/signalhandlers.rs
+++ b/crates/runtime/src/signalhandlers.rs
@@ -5,10 +5,10 @@
 #![allow(non_snake_case)]
 
 use crate::vmcontext::VMContext;
-use crate::RwLock;
-use core::borrow::{Borrow, BorrowMut};
-use core::cell::Cell;
 use lazy_static::lazy_static;
+use std::borrow::{Borrow, BorrowMut};
+use std::cell::Cell;
+use std::sync::RwLock;
 
 #[derive(Default)]
 struct TrapContext {
diff --git a/crates/runtime/src/table.rs b/crates/runtime/src/table.rs
index 13b55f6c7d..c7fb288f53 100644
--- a/crates/runtime/src/table.rs
+++ b/crates/runtime/src/table.rs
@@ -3,9 +3,8 @@
 //! `Table` is to WebAssembly tables what `LinearMemory` is to WebAssembly linear memories.
 
 use crate::vmcontext::{VMCallerCheckedAnyfunc, VMTableDefinition};
-use alloc::vec::Vec;
-use core::convert::{TryFrom, TryInto};
 use cranelift_wasm::TableElementType;
+use std::convert::{TryFrom, TryInto};
 use wasmtime_environ::{TablePlan, TableStyle};
 
 /// A table instance.
diff --git a/crates/runtime/src/trap_registry.rs b/crates/runtime/src/trap_registry.rs
index 33bcf2b0e3..b62d58392b 100644
--- a/crates/runtime/src/trap_registry.rs
+++ b/crates/runtime/src/trap_registry.rs
@@ -1,7 +1,7 @@
-use crate::HashMap;
-use crate::{RwLock, RwLockReadGuard, RwLockWriteGuard};
 use cranelift_codegen::ir;
 use lazy_static::lazy_static;
+use std::collections::HashMap;
+use std::sync::{RwLock, RwLockReadGuard, RwLockWriteGuard};
 
 lazy_static! {
     static ref REGISTRY: RwLock<TrapRegistry> = RwLock::new(TrapRegistry::default());
diff --git a/crates/runtime/src/traphandlers.rs b/crates/runtime/src/traphandlers.rs
index 5ddb3563c5..83ecb0a17c 100644
--- a/crates/runtime/src/traphandlers.rs
+++ b/crates/runtime/src/traphandlers.rs
@@ -4,10 +4,9 @@
 use crate::trap_registry::get_trap_registry;
 use crate::trap_registry::TrapDescription;
 use crate::vmcontext::{VMContext, VMFunctionBody};
-use alloc::string::{String, ToString};
-use core::cell::Cell;
-use core::ptr;
 use cranelift_codegen::ir;
+use std::cell::Cell;
+use std::ptr;
 
 extern "C" {
     fn WasmtimeCallTrampoline(
diff --git a/crates/runtime/src/vmcontext.rs b/crates/runtime/src/vmcontext.rs
index 536e28dcb3..2a29d558ea 100644
--- a/crates/runtime/src/vmcontext.rs
+++ b/crates/runtime/src/vmcontext.rs
@@ -2,8 +2,8 @@
 //! fields that compiled wasm code accesses directly.
 
 use crate::instance::Instance;
-use core::any::Any;
-use core::{ptr, u32};
+use std::any::Any;
+use std::{ptr, u32};
 use wasmtime_environ::BuiltinFunctionIndex;
 
 /// An imported function.
@@ -20,8 +20,8 @@ pub struct VMFunctionImport {
 #[cfg(test)]
 mod test_vmfunction_import {
     use super::VMFunctionImport;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -53,7 +53,7 @@ pub struct VMFunctionBody(u8);
 #[cfg(test)]
 mod test_vmfunction_body {
     use super::VMFunctionBody;
-    use core::mem::size_of;
+    use std::mem::size_of;
 
     #[test]
     fn check_vmfunction_body_offsets() {
@@ -76,8 +76,8 @@ pub struct VMTableImport {
 #[cfg(test)]
 mod test_vmtable_import {
     use super::VMTableImport;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -114,8 +114,8 @@ pub struct VMMemoryImport {
 #[cfg(test)]
 mod test_vmmemory_import {
     use super::VMMemoryImport;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -149,8 +149,8 @@ pub struct VMGlobalImport {
 #[cfg(test)]
 mod test_vmglobal_import {
     use super::VMGlobalImport;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -184,8 +184,8 @@ pub struct VMMemoryDefinition {
 #[cfg(test)]
 mod test_vmmemory_definition {
     use super::VMMemoryDefinition;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -228,8 +228,8 @@ pub struct VMTableDefinition {
 #[cfg(test)]
 mod test_vmtable_definition {
     use super::VMTableDefinition;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -265,8 +265,8 @@ pub struct VMGlobalDefinition {
 #[cfg(test)]
 mod test_vmglobal_definition {
     use super::VMGlobalDefinition;
-    use core::mem::{align_of, size_of};
     use more_asserts::assert_ge;
+    use std::mem::{align_of, size_of};
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -432,7 +432,7 @@ pub struct VMSharedSignatureIndex(u32);
 #[cfg(test)]
 mod test_vmshared_signature_index {
     use super::VMSharedSignatureIndex;
-    use core::mem::size_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, TargetSharedSignatureIndex, VMOffsets};
 
     #[test]
@@ -485,8 +485,8 @@ pub struct VMCallerCheckedAnyfunc {
 #[cfg(test)]
 mod test_vmcaller_checked_anyfunc {
     use super::VMCallerCheckedAnyfunc;
-    use core::mem::size_of;
     use memoffset::offset_of;
+    use std::mem::size_of;
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
@@ -559,7 +559,7 @@ pub struct VMInvokeArgument([u8; 16]);
 #[cfg(test)]
 mod test_vm_invoke_argument {
     use super::VMInvokeArgument;
-    use core::mem::{align_of, size_of};
+    use std::mem::{align_of, size_of};
     use wasmtime_environ::{Module, VMOffsets};
 
     #[test]
diff --git a/crates/wasi-c/src/instantiate.rs b/crates/wasi-c/src/instantiate.rs
index 2304b1faf4..21d3f908d5 100644
--- a/crates/wasi-c/src/instantiate.rs
+++ b/crates/wasi-c/src/instantiate.rs
@@ -3,17 +3,17 @@ use crate::host::{
     fd_table, fd_table_init, fd_table_insert_existing,
 };
 use crate::syscalls;
-use alloc::rc::Rc;
-use core::cell::RefCell;
 use cranelift_codegen::ir::types;
 use cranelift_codegen::{ir, isa};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::DefinedFuncIndex;
+use std::cell::RefCell;
 use std::collections::HashMap;
 use std::ffi::CString;
 use std::fs::File;
 use std::mem;
 use std::os::unix::io::AsRawFd;
+use std::rc::Rc;
 use target_lexicon::HOST;
 use wasmtime_environ::{translate_signature, Export, Module};
 use wasmtime_runtime::{Imports, InstanceHandle, InstantiationError, VMFunctionBody};
diff --git a/crates/wasi-c/src/lib.rs b/crates/wasi-c/src/lib.rs
index 1b2b0b28cd..c7969ac3d5 100644
--- a/crates/wasi-c/src/lib.rs
+++ b/crates/wasi-c/src/lib.rs
@@ -1,6 +1,3 @@
-extern crate alloc;
-extern crate core;
-
 mod host;
 mod instantiate;
 mod syscalls;
diff --git a/crates/wasi-c/src/syscalls.rs b/crates/wasi-c/src/syscalls.rs
index 5a163cae57..7a084e855f 100644
--- a/crates/wasi-c/src/syscalls.rs
+++ b/crates/wasi-c/src/syscalls.rs
@@ -2,9 +2,9 @@ use crate::host::{argv_environ_values, fd_prestats, fd_table};
 use crate::instantiate::WASIState;
 use crate::translate::*;
 use crate::{host, wasm32};
-use core::convert::TryFrom;
 use cranelift_codegen::ir::types::{Type, I32, I64};
 use log::{log_enabled, trace};
+use std::convert::TryFrom;
 use std::{mem, ptr, slice, str};
 use wasmtime_runtime::VMContext;
 
diff --git a/crates/wasi-c/src/translate.rs b/crates/wasi-c/src/translate.rs
index bda431ee1f..92de75db93 100644
--- a/crates/wasi-c/src/translate.rs
+++ b/crates/wasi-c/src/translate.rs
@@ -1,7 +1,7 @@
 use crate::{host, wasm32};
-use core::convert::TryFrom;
 use log::{debug, error};
 use more_asserts::assert_le;
+use std::convert::TryFrom;
 use std::mem::{align_of, size_of, zeroed};
 use std::slice;
 use wasmtime_runtime::{Export, VMContext};
diff --git a/crates/wasi-c/src/wasm32.rs b/crates/wasi-c/src/wasm32.rs
index 26f8b35ba8..2178e7f818 100644
--- a/crates/wasi-c/src/wasm32.rs
+++ b/crates/wasi-c/src/wasm32.rs
@@ -108,7 +108,7 @@ fn bindgen_test_layout_fsid_t() {
         concat!("Alignment of ", stringify!(fsid_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<fsid_t>())).__val as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<fsid_t>())).__val as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -167,7 +167,7 @@ fn bindgen_test_layout_wasi_dirent_t() {
         concat!("Size of: ", stringify!(__wasi_dirent_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_dirent_t>())).d_next as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_dirent_t>())).d_next as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -177,7 +177,7 @@ fn bindgen_test_layout_wasi_dirent_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_dirent_t>())).d_ino as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_dirent_t>())).d_ino as *const _ as usize },
         8usize,
         concat!(
             "Offset of field: ",
@@ -187,7 +187,7 @@ fn bindgen_test_layout_wasi_dirent_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_dirent_t>())).d_namlen as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_dirent_t>())).d_namlen as *const _ as usize },
         16usize,
         concat!(
             "Offset of field: ",
@@ -197,7 +197,7 @@ fn bindgen_test_layout_wasi_dirent_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_dirent_t>())).d_type as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_dirent_t>())).d_type as *const _ as usize },
         20usize,
         concat!(
             "Offset of field: ",
@@ -249,7 +249,7 @@ fn bindgen_test_layout___wasi_event_t___wasi_event_u___wasi_event_u_fd_readwrite
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t___wasi_event_u___wasi_event_u_fd_readwrite_t>()))
+            &(*(std::ptr::null::<__wasi_event_t___wasi_event_u___wasi_event_u_fd_readwrite_t>()))
                 .nbytes as *const _ as usize
         },
         0usize,
@@ -262,7 +262,7 @@ fn bindgen_test_layout___wasi_event_t___wasi_event_u___wasi_event_u_fd_readwrite
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t___wasi_event_u___wasi_event_u_fd_readwrite_t>()))
+            &(*(std::ptr::null::<__wasi_event_t___wasi_event_u___wasi_event_u_fd_readwrite_t>()))
                 .flags as *const _ as usize
         },
         8usize,
@@ -288,7 +288,7 @@ fn bindgen_test_layout___wasi_event_t___wasi_event_u() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t___wasi_event_u>())).fd_readwrite as *const _
+            &(*(std::ptr::null::<__wasi_event_t___wasi_event_u>())).fd_readwrite as *const _
                 as usize
         },
         0usize,
@@ -313,7 +313,7 @@ fn bindgen_test_layout___wasi_event_t() {
         concat!("Alignment of ", stringify!(__wasi_event_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).userdata as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).userdata as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -323,7 +323,7 @@ fn bindgen_test_layout___wasi_event_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).error as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).error as *const _ as usize },
         8usize,
         concat!(
             "Offset of field: ",
@@ -333,7 +333,7 @@ fn bindgen_test_layout___wasi_event_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).type_ as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).type_ as *const _ as usize },
         10usize,
         concat!(
             "Offset of field: ",
@@ -343,7 +343,7 @@ fn bindgen_test_layout___wasi_event_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).u as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).u as *const _ as usize },
         16usize,
         concat!(
             "Offset of field: ",
@@ -389,7 +389,7 @@ fn bindgen_test_layout___wasi_prestat_t___wasi_prestat_u___wasi_prestat_u_dir_t(
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_prestat_t___wasi_prestat_u___wasi_prestat_u_dir_t>()))
+            &(*(std::ptr::null::<__wasi_prestat_t___wasi_prestat_u___wasi_prestat_u_dir_t>()))
                 .pr_name_len as *const _ as usize
         },
         0usize,
@@ -418,7 +418,7 @@ fn bindgen_test_layout___wasi_prestat_t___wasi_prestat_u() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_prestat_t___wasi_prestat_u>())).dir as *const _ as usize
+            &(*(std::ptr::null::<__wasi_prestat_t___wasi_prestat_u>())).dir as *const _ as usize
         },
         0usize,
         concat!(
@@ -442,7 +442,7 @@ fn bindgen_test_layout___wasi_prestat_t() {
         concat!("Alignment of ", stringify!(__wasi_prestat_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_prestat_t>())).pr_type as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_prestat_t>())).pr_type as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -452,7 +452,7 @@ fn bindgen_test_layout___wasi_prestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_prestat_t>())).u as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_prestat_t>())).u as *const _ as usize },
         4usize,
         concat!(
             "Offset of field: ",
@@ -489,8 +489,8 @@ fn bindgen_test_layout_wasi_event_t__bindgen_ty_1__bindgen_ty_1() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_1>())).nbytes
-                as *const _ as usize
+            &(*(std::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_1>())).nbytes as *const _
+                as usize
         },
         0usize,
         concat!(
@@ -502,8 +502,8 @@ fn bindgen_test_layout_wasi_event_t__bindgen_ty_1__bindgen_ty_1() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_1>())).flags
-                as *const _ as usize
+            &(*(std::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_1>())).flags as *const _
+                as usize
         },
         8usize,
         concat!(
@@ -541,8 +541,8 @@ fn bindgen_test_layout_wasi_event_t__bindgen_ty_1__bindgen_ty_2() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_2>())).signal
-                as *const _ as usize
+            &(*(std::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_2>())).signal as *const _
+                as usize
         },
         0usize,
         concat!(
@@ -554,7 +554,7 @@ fn bindgen_test_layout_wasi_event_t__bindgen_ty_1__bindgen_ty_2() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_2>())).exitcode
+            &(*(std::ptr::null::<__wasi_event_t__bindgen_ty_1__bindgen_ty_2>())).exitcode
                 as *const _ as usize
         },
         4usize,
@@ -576,8 +576,7 @@ fn bindgen_test_layout_wasi_event_t__bindgen_ty_1() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_event_t__bindgen_ty_1>())).fd_readwrite as *const _
-                as usize
+            &(*(std::ptr::null::<__wasi_event_t__bindgen_ty_1>())).fd_readwrite as *const _ as usize
         },
         0usize,
         concat!(
@@ -596,7 +595,7 @@ fn bindgen_test_layout_wasi_event_t() {
         concat!("Size of: ", stringify!(__wasi_event_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).userdata as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).userdata as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -606,7 +605,7 @@ fn bindgen_test_layout_wasi_event_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).error as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).error as *const _ as usize },
         8usize,
         concat!(
             "Offset of field: ",
@@ -616,7 +615,7 @@ fn bindgen_test_layout_wasi_event_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_event_t>())).type_ as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_event_t>())).type_ as *const _ as usize },
         10usize,
         concat!(
             "Offset of field: ",
@@ -643,7 +642,7 @@ fn bindgen_test_layout_wasi_fdstat_t() {
         concat!("Size of: ", stringify!(__wasi_fdstat_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_fdstat_t>())).fs_filetype as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_fdstat_t>())).fs_filetype as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -653,7 +652,7 @@ fn bindgen_test_layout_wasi_fdstat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_fdstat_t>())).fs_flags as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_fdstat_t>())).fs_flags as *const _ as usize },
         2usize,
         concat!(
             "Offset of field: ",
@@ -663,7 +662,7 @@ fn bindgen_test_layout_wasi_fdstat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_fdstat_t>())).fs_rights_base as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_fdstat_t>())).fs_rights_base as *const _ as usize },
         8usize,
         concat!(
             "Offset of field: ",
@@ -674,7 +673,7 @@ fn bindgen_test_layout_wasi_fdstat_t() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_fdstat_t>())).fs_rights_inheriting as *const _ as usize
+            &(*(std::ptr::null::<__wasi_fdstat_t>())).fs_rights_inheriting as *const _ as usize
         },
         16usize,
         concat!(
@@ -705,7 +704,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         concat!("Size of: ", stringify!(__wasi_filestat_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_dev as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_dev as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -715,7 +714,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_ino as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_ino as *const _ as usize },
         8usize,
         concat!(
             "Offset of field: ",
@@ -725,7 +724,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_filetype as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_filetype as *const _ as usize },
         16usize,
         concat!(
             "Offset of field: ",
@@ -735,7 +734,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_nlink as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_nlink as *const _ as usize },
         20usize,
         concat!(
             "Offset of field: ",
@@ -745,7 +744,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_size as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_size as *const _ as usize },
         24usize,
         concat!(
             "Offset of field: ",
@@ -755,7 +754,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_atim as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_atim as *const _ as usize },
         32usize,
         concat!(
             "Offset of field: ",
@@ -765,7 +764,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_mtim as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_mtim as *const _ as usize },
         40usize,
         concat!(
             "Offset of field: ",
@@ -775,7 +774,7 @@ fn bindgen_test_layout_wasi_filestat_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_filestat_t>())).st_ctim as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_filestat_t>())).st_ctim as *const _ as usize },
         48usize,
         concat!(
             "Offset of field: ",
@@ -804,7 +803,7 @@ fn bindgen_test_layout_wasi_ciovec_t() {
         concat!("Alignment of ", stringify!(__wasi_ciovec_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_ciovec_t>())).buf as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_ciovec_t>())).buf as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -814,7 +813,7 @@ fn bindgen_test_layout_wasi_ciovec_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_ciovec_t>())).buf_len as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_ciovec_t>())).buf_len as *const _ as usize },
         4usize,
         concat!(
             "Offset of field: ",
@@ -843,7 +842,7 @@ fn bindgen_test_layout_wasi_iovec_t() {
         concat!("Alignment of ", stringify!(__wasi_iovec_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_iovec_t>())).buf as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_iovec_t>())).buf as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -853,7 +852,7 @@ fn bindgen_test_layout_wasi_iovec_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_iovec_t>())).buf_len as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_iovec_t>())).buf_len as *const _ as usize },
         4usize,
         concat!(
             "Offset of field: ",
@@ -914,7 +913,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u___wasi_subscr
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<
+            &(*(std::ptr::null::<
                 __wasi_subscription_t___wasi_subscription_u___wasi_subscription_u_clock_t,
             >()))
             .identifier as *const _ as usize
@@ -929,7 +928,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u___wasi_subscr
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<
+            &(*(std::ptr::null::<
                 __wasi_subscription_t___wasi_subscription_u___wasi_subscription_u_clock_t,
             >()))
             .clock_id as *const _ as usize
@@ -944,7 +943,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u___wasi_subscr
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<
+            &(*(std::ptr::null::<
                 __wasi_subscription_t___wasi_subscription_u___wasi_subscription_u_clock_t,
             >()))
             .timeout as *const _ as usize
@@ -959,7 +958,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u___wasi_subscr
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<
+            &(*(std::ptr::null::<
                 __wasi_subscription_t___wasi_subscription_u___wasi_subscription_u_clock_t,
             >()))
             .precision as *const _ as usize
@@ -974,7 +973,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u___wasi_subscr
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<
+            &(*(std::ptr::null::<
                 __wasi_subscription_t___wasi_subscription_u___wasi_subscription_u_clock_t,
             >()))
             .flags as *const _ as usize
@@ -1022,7 +1021,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u___wasi_subscr
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<
+            &(*(std::ptr::null::<
                 __wasi_subscription_t___wasi_subscription_u___wasi_subscription_u_fd_readwrite_t,
             >()))
             .fd as *const _ as usize
@@ -1058,8 +1057,8 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_subscription_t___wasi_subscription_u>())).clock
-                as *const _ as usize
+            &(*(std::ptr::null::<__wasi_subscription_t___wasi_subscription_u>())).clock as *const _
+                as usize
         },
         0usize,
         concat!(
@@ -1071,7 +1070,7 @@ fn bindgen_test_layout___wasi_subscription_t___wasi_subscription_u() {
     );
     assert_eq!(
         unsafe {
-            &(*(::core::ptr::null::<__wasi_subscription_t___wasi_subscription_u>())).fd_readwrite
+            &(*(std::ptr::null::<__wasi_subscription_t___wasi_subscription_u>())).fd_readwrite
                 as *const _ as usize
         },
         0usize,
@@ -1096,7 +1095,7 @@ fn bindgen_test_layout___wasi_subscription_t() {
         concat!("Alignment of ", stringify!(__wasi_subscription_t))
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_subscription_t>())).userdata as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_subscription_t>())).userdata as *const _ as usize },
         0usize,
         concat!(
             "Offset of field: ",
@@ -1106,7 +1105,7 @@ fn bindgen_test_layout___wasi_subscription_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_subscription_t>())).type_ as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_subscription_t>())).type_ as *const _ as usize },
         8usize,
         concat!(
             "Offset of field: ",
@@ -1116,7 +1115,7 @@ fn bindgen_test_layout___wasi_subscription_t() {
         )
     );
     assert_eq!(
-        unsafe { &(*(::core::ptr::null::<__wasi_subscription_t>())).u as *const _ as usize },
+        unsafe { &(*(std::ptr::null::<__wasi_subscription_t>())).u as *const _ as usize },
         16usize,
         concat!(
             "Offset of field: ",
diff --git a/crates/wasi/src/instantiate.rs b/crates/wasi/src/instantiate.rs
index 8c92b01f64..270ea6635a 100644
--- a/crates/wasi/src/instantiate.rs
+++ b/crates/wasi/src/instantiate.rs
@@ -1,12 +1,12 @@
 use super::syscalls;
-use alloc::rc::Rc;
-use core::cell::RefCell;
 use cranelift_codegen::ir::types;
 use cranelift_codegen::{ir, isa};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::DefinedFuncIndex;
+use std::cell::RefCell;
 use std::collections::HashMap;
 use std::fs::File;
+use std::rc::Rc;
 use target_lexicon::HOST;
 use wasi_common::{WasiCtx, WasiCtxBuilder};
 use wasmtime_api as api;
diff --git a/crates/wasi/src/lib.rs b/crates/wasi/src/lib.rs
index ef699ce0b6..3820b49ca3 100644
--- a/crates/wasi/src/lib.rs
+++ b/crates/wasi/src/lib.rs
@@ -1,7 +1,5 @@
 #![allow(improper_ctypes)]
 
-extern crate alloc;
-
 mod instantiate;
 mod syscalls;
 
diff --git a/crates/wast/src/lib.rs b/crates/wast/src/lib.rs
index 182be4a1d0..4f8f54f733 100644
--- a/crates/wast/src/lib.rs
+++ b/crates/wast/src/lib.rs
@@ -22,8 +22,6 @@
     )
 )]
 
-extern crate alloc;
-
 mod spectest;
 mod wast;
 
diff --git a/crates/wast/src/spectest.rs b/crates/wast/src/spectest.rs
index e1e3d9a1bd..5d8649e925 100644
--- a/crates/wast/src/spectest.rs
+++ b/crates/wast/src/spectest.rs
@@ -1,12 +1,12 @@
 #![allow(improper_ctypes)]
 
-use alloc::rc::Rc;
-use core::cell::RefCell;
 use cranelift_codegen::ir::types;
 use cranelift_codegen::{ir, isa};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::{DefinedFuncIndex, Global, GlobalInit, Memory, Table, TableElementType};
+use std::cell::RefCell;
 use std::collections::hash_map::HashMap;
+use std::rc::Rc;
 use target_lexicon::HOST;
 use wasmtime_environ::{translate_signature, Export, MemoryPlan, Module, TablePlan};
 use wasmtime_jit::target_tunables;
diff --git a/docs/stability-platform-support.md b/docs/stability-platform-support.md
index 024c21e296..d2ed7fb8bf 100644
--- a/docs/stability-platform-support.md
+++ b/docs/stability-platform-support.md
@@ -1,3 +1,43 @@
 # Platform Support
 
-... more coming soon
+The `wasmtime` project is a configurable and lightweight runtime for WebAssembly
+which has a number of ways it can be configured. Not all features are supported
+on all platforms, but it is intended that `wasmtime` can run in some capacity on
+almost all platforms! The matrix of what's being tested, what works, and what's
+supported where is evolving over time, and this document hopes to capture a
+snapshot of what the current state of the world looks like.
+
+All features of `wasmtime` should work on the following platforms:
+
+* Linux x86\_64
+* macOS x86\_64
+* Windows x86\_64
+
+For more detailed information about supported platforms, please check out the
+sections below!
+
+## JIT compiler support
+
+The JIT compiler, backed by either `lightbeam` or `cranelift` supports only the
+x86\_64 architecture at this time. Support for at least ARM, AArch64, and x86 is
+planned at this time.
+
+Usage of the JIT compiler will require a host operating system which supports
+creating executable memory pages on-the-fly. In Rust terms this generally means
+that `std` needs to be supported on this platform.
+
+## Interpreter support
+
+At this time `wasmtime` does not have a mode in which it simply interprets
+WebAssembly code. It is planned to add support for an interpreter, however, and
+this will have minimal system dependencies. It is planned that the system will
+need to support some form of dynamic memory allocation, but other than that not
+much else will be needed.
+
+## What about `#[no_std]`?
+
+The `wasmtime` project does not currently use `#[no_std]` for its crates, but
+this is not because it won't support it! At this time we're still gathering use
+cases for for what `#[no_std]` might entail, so if you're interested in this
+we'd love to hear about your use case! Feel free to open an issue on the
+`wasmtime` repository to discuss this.
diff --git a/fuzz/fuzz_targets/compile.rs b/fuzz/fuzz_targets/compile.rs
index 3d139e6921..134facb43a 100644
--- a/fuzz/fuzz_targets/compile.rs
+++ b/fuzz/fuzz_targets/compile.rs
@@ -1,14 +1,12 @@
 #![no_main]
 
-extern crate alloc;
-extern crate core;
 extern crate libfuzzer_sys;
 
-use alloc::rc::Rc;
-use core::cell::RefCell;
 use cranelift_codegen::settings;
 use libfuzzer_sys::fuzz_target;
+use std::cell::RefCell;
 use std::collections::HashMap;
+use std::rc::Rc;
 use wasmparser::validate;
 use wasmtime_jit::{CompilationStrategy, CompiledModule, Compiler, NullResolver};
 
diff --git a/tests/instantiate.rs b/tests/instantiate.rs
index f77e3bffc2..5a51ab4c8e 100644
--- a/tests/instantiate.rs
+++ b/tests/instantiate.rs
@@ -1,12 +1,10 @@
-extern crate alloc;
-
-use alloc::rc::Rc;
-use core::cell::RefCell;
 use cranelift_codegen::settings;
 use cranelift_codegen::settings::Configurable;
 use more_asserts::assert_gt;
+use std::cell::RefCell;
 use std::collections::HashMap;
 use std::path::PathBuf;
+use std::rc::Rc;
 use wasmtime_jit::{instantiate, CompilationStrategy, Compiler, NullResolver};
 
 const PATH_MODULE_RS2WASM_ADD_FUNC: &str = r"tests/wat/rs2wasm-add-func.wat";