Adjust no_std usage in Wasmi workspace crates (#1307)

* adjust no_std usage in wasmi_core

* adjust no_std usage for wasmi_collections

* adjust no_std usage for wasmi_ir

* adjust no_std usage in wasmi

* apply rustfmt

crates/collections/src/arena/component_vec.rs

@@ -1,10 +1,10 @@
 use crate::arena::ArenaIndex;
+use alloc::vec::Vec;
 use core::{
     fmt::{self, Debug},
     marker::PhantomData,
     ops::{Index, IndexMut},
 };
-use std::vec::Vec;
 
 /// Stores components for entities backed by a [`Vec`].
 pub struct ComponentVec<Idx, T> {

crates/collections/src/arena/mod.rs

@@ -9,13 +9,13 @@ mod dedup;
 mod guarded;
 
 pub use self::{component_vec::ComponentVec, dedup::DedupArena, guarded::GuardedEntity};
+use alloc::vec::Vec;
 use core::{
     iter::Enumerate,
     marker::PhantomData,
     ops::{Index, IndexMut, Range},
     slice,
 };
-use std::vec::Vec;
 
 /// Types that can be used as indices for arenas.
 pub trait ArenaIndex: Copy {

crates/collections/src/head_vec.rs

@@ -1,5 +1,5 @@
+use alloc::vec::Vec;
 use core::mem;
-use std::vec::Vec;
 
 /// A [`Vec`]-like data structure with fast access to the last item.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]

crates/collections/src/lib.rs

@@ -30,9 +30,7 @@
     clippy::items_after_statements
 )]
 
-#[cfg(not(feature = "std"))]
-extern crate alloc as std;
-
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate std;
 

crates/collections/src/map.rs

@@ -1,7 +1,6 @@
 //! Type definitions for a default map.
 
-use core::{borrow::Borrow, hash::Hash, iter::FusedIterator, ops::Index};
-use std::fmt::Debug;
+use core::{borrow::Borrow, fmt::Debug, hash::Hash, iter::FusedIterator, ops::Index};
 
 #[cfg(all(
     feature = "hash-collections",
@@ -30,7 +29,7 @@ mod detail {
     feature = "prefer-btree-collections"
 ))]
 mod detail {
-    use std::collections::btree_map;
+    use alloc::collections::btree_map;
 
     pub type MapImpl<K, V> = btree_map::BTreeMap<K, V>;
     pub type EntryImpl<'a, K, V> = btree_map::Entry<'a, K, V>;

crates/collections/src/set.rs

@@ -31,7 +31,7 @@ mod detail {
     feature = "prefer-btree-collections"
 ))]
 mod detail {
-    use std::collections::btree_set;
+    use alloc::collections::btree_set;
 
     pub type SetImpl<T> = btree_set::BTreeSet<T>;
     pub type IterImpl<'a, T> = btree_set::Iter<'a, T>;

crates/collections/src/string_interner/detail.rs

@@ -1,11 +1,11 @@
 use super::{GetOrInternWithHint, InternHint, Sym};
-use core::{cmp::Ordering, mem, ops::Deref};
-use std::{
+use alloc::{
     borrow::Borrow,
     collections::{btree_map::Entry, BTreeMap},
     sync::Arc,
     vec::Vec,
 };
+use core::{cmp::Ordering, mem, ops::Deref};
 
 pub type StringInternerImpl = StringInterner;
 

crates/core/src/lib.rs

@@ -20,9 +20,7 @@ mod units;
 mod untyped;
 mod value;
 
-#[cfg(not(feature = "std"))]
-extern crate alloc as std;
-
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate std;
 

crates/core/src/trap.rs

@@ -1,6 +1,6 @@
 use crate::HostError;
+use alloc::{boxed::Box, string::String};
 use core::fmt::{self, Display};
-use std::{boxed::Box, string::String};
 
 #[cfg(feature = "std")]
 use std::error::Error as StdError;

crates/ir/src/lib.rs

@@ -1,8 +1,6 @@
-#![cfg_attr(not(feature = "std"), no_std)]
-
-#[cfg(not(feature = "std"))]
-extern crate alloc as std;
+#![no_std]
 
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate std;
 

crates/ir/src/sequence.rs

@@ -3,7 +3,7 @@ use ::core::{
     num::{NonZeroI32, NonZeroI64, NonZeroU32, NonZeroU64},
     slice,
 };
-use std::{boxed::Box, vec::Vec};
+use alloc::{boxed::Box, vec::Vec};
 
 /// A sequence of [`Instruction`]s.
 #[derive(Debug, Default, Clone, PartialEq, Eq)]

crates/wasmi/src/engine/code_map.rs

@@ -22,6 +22,7 @@ use crate::{
     Config,
     Error,
 };
+use alloc::boxed::Box;
 use core::{
     fmt,
     mem::{self, MaybeUninit},
@@ -30,7 +31,6 @@ use core::{
     slice,
 };
 use spin::Mutex;
-use std::boxed::Box;
 use wasmparser::{FuncToValidate, ValidatorResources, WasmFeatures};
 
 /// A reference to a compiled function stored in the [`CodeMap`] of an [`Engine`](crate::Engine).

crates/wasmi/src/engine/executor/instrs/call.rs

@@ -18,8 +18,7 @@ use crate::{
     Instance,
     Store,
 };
-use core::array;
-use std::fmt;
+use core::{array, fmt};
 
 /// Dispatches and executes the host function.
 ///

crates/wasmi/src/engine/executor/stack/calls.rs

@@ -6,7 +6,7 @@ use crate::{
     ir::RegSpan,
     Instance,
 };
-use std::vec::Vec;
+use alloc::vec::Vec;
 
 #[cfg(doc)]
 use crate::{

crates/wasmi/src/engine/executor/stack/values.rs

@@ -4,14 +4,14 @@ use crate::{
     engine::code_map::CompiledFuncRef,
     ir::Reg,
 };
+use alloc::vec::Vec;
 use core::{
     fmt::{self, Debug},
     mem::{self, MaybeUninit},
     ops::Range,
     ptr,
     slice,
 };
-use std::vec::Vec;
 
 #[cfg(doc)]
 use super::calls::CallFrame;

crates/wasmi/src/engine/mod.rs

@@ -52,12 +52,12 @@ use crate::{
     FuncType,
     StoreContextMut,
 };
-use core::sync::atomic::{AtomicU32, Ordering};
-use spin::{Mutex, RwLock};
-use std::{
+use alloc::{
     sync::{Arc, Weak},
     vec::Vec,
 };
+use core::sync::atomic::{AtomicU32, Ordering};
+use spin::{Mutex, RwLock};
 use wasmparser::{FuncToValidate, FuncValidatorAllocations, ValidatorResources};
 
 #[cfg(doc)]

crates/wasmi/src/engine/translator/control_stack.rs

@@ -4,7 +4,7 @@ use crate::{
     engine::translator::{Provider, ProviderSliceStack},
     Error,
 };
-use std::vec::{Drain, Vec};
+use alloc::vec::{Drain, Vec};
 
 /// An acquired branch target.
 #[derive(Debug)]

crates/wasmi/src/engine/translator/instr_encoder.rs

@@ -33,8 +33,8 @@ use crate::{
     module::ModuleHeader,
     Error,
 };
+use alloc::vec::{Drain, Vec};
 use core::mem;
-use std::vec::{Drain, Vec};
 
 /// A reference to an instruction of the partially
 /// constructed function body of the [`InstrEncoder`].

crates/wasmi/src/engine/translator/labels.rs

@@ -1,10 +1,10 @@
 use super::Instr;
 use crate::{ir::BranchOffset, Error};
+use alloc::vec::Vec;
 use core::{
     fmt::{self, Display},
     slice::Iter as SliceIter,
 };
-use std::vec::Vec;
 
 /// A label during the Wasmi compilation process.
 #[derive(Debug, Copy, Clone)]

crates/wasmi/src/engine/translator/mod.rs

@@ -65,9 +65,9 @@ use crate::{
     FuncRef,
     FuncType,
 };
+use alloc::vec::Vec;
 use core::fmt;
 use stack::RegisterSpace;
-use std::vec::Vec;
 use utils::Wrap;
 use wasmparser::{
     BinaryReaderError,

crates/wasmi/src/engine/translator/provider.rs

@@ -4,7 +4,7 @@ use crate::{
     ir::{AnyConst32, Reg},
     Error,
 };
-use std::vec::{Drain, Vec};
+use alloc::vec::{Drain, Vec};
 
 #[cfg(doc)]
 use super::Instruction;

crates/wasmi/src/engine/translator/stack/consts.rs

@@ -1,10 +1,10 @@
 use super::Reg;
 use crate::{core::UntypedVal, engine::TranslationError, Error};
-use core::{iter::Rev, slice::Iter as SliceIter};
-use std::{
+use alloc::{
     collections::{btree_map, BTreeMap},
     vec::Vec,
 };
+use core::{iter::Rev, slice::Iter as SliceIter};
 
 /// A pool of deduplicated function local constant values.
 ///

crates/wasmi/src/engine/translator/stack/locals.rs

@@ -1,9 +1,9 @@
 use crate::{ir::Reg, Error};
-use core::mem;
-use std::{
+use alloc::{
     collections::{btree_map, BTreeMap},
     vec::Vec,
 };
+use core::mem;
 
 #[cfg(doc)]
 use super::ProviderStack;

crates/wasmi/src/engine/translator/stack/mod.rs

@@ -19,7 +19,7 @@ use crate::{
     ir::{Reg, RegSpan},
     Error,
 };
-use std::vec::Vec;
+use alloc::vec::Vec;
 
 /// Typed inputs to Wasmi bytecode instructions.
 ///

crates/wasmi/src/engine/translator/stack/provider.rs

@@ -1,7 +1,7 @@
 use super::{LocalRefs, RegisterAlloc, TypedVal};
 use crate::{engine::translator::PreservedLocal, ir::Reg, Error};
+use alloc::vec::Vec;
 use arrayvec::ArrayVec;
-use std::vec::Vec;
 
 #[cfg(doc)]
 use crate::core::UntypedVal;

crates/wasmi/src/engine/translator/stack/register_alloc.rs

@@ -4,12 +4,12 @@ use crate::{
     ir::{Reg, RegSpan},
     Error,
 };
+use alloc::collections::BTreeSet;
 use core::{
     cmp::{max, min},
     num::NonZeroUsize,
 };
 use multi_stash::{Key, Key as StashKey, MultiStash};
-use std::collections::BTreeSet;
 
 #[cfg(doc)]
 use crate::engine::translator::InstrEncoder;

crates/wasmi/src/error.rs

@@ -14,8 +14,8 @@ use crate::{
     engine::{ResumableHostError, TranslationError},
     module::ReadError,
 };
+use alloc::{boxed::Box, string::String};
 use core::{fmt, fmt::Display};
-use std::{boxed::Box, string::String};
 use wasmparser::BinaryReaderError as WasmError;
 
 /// The generic Wasmi root error type.

crates/wasmi/src/externref.rs

@@ -5,8 +5,8 @@ use crate::{
     AsContextMut,
     StoreContext,
 };
+use alloc::boxed::Box;
 use core::{any::Any, mem, num::NonZeroU32};
-use std::boxed::Box;
 
 /// A raw index to a function entity.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]

crates/wasmi/src/func/func_type.rs

@@ -1,6 +1,6 @@
 use crate::{core::ValType, func::FuncError, Val};
+use alloc::{sync::Arc, vec::Vec};
 use core::fmt;
-use std::{sync::Arc, vec::Vec};
 
 /// A function type representing a function's parameter and result types.
 ///

crates/wasmi/src/func/mod.rs

@@ -23,8 +23,8 @@ use super::{
     Stored,
 };
 use crate::{collections::arena::ArenaIndex, engine::ResumableCall, Engine, Error, Val};
+use alloc::{boxed::Box, sync::Arc};
 use core::{fmt, fmt::Debug, num::NonZeroU32};
-use std::{boxed::Box, sync::Arc};
 
 /// A raw index to a function entity.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]

crates/wasmi/src/instance/builder.rs

@@ -13,7 +13,7 @@ use crate::{
     Module,
     Table,
 };
-use std::{boxed::Box, sync::Arc, vec::Vec};
+use alloc::{boxed::Box, sync::Arc, vec::Vec};
 
 /// A module instance entity builder.
 #[derive(Debug)]

crates/wasmi/src/instance/exports.rs

@@ -10,8 +10,8 @@ use crate::{
     Table,
     TableType,
 };
+use alloc::boxed::Box;
 use core::iter::FusedIterator;
-use std::boxed::Box;
 
 /// An external item to a WebAssembly module.
 ///

crates/wasmi/src/instance/mod.rs

@@ -22,7 +22,7 @@ use crate::{
     WasmParams,
     WasmResults,
 };
-use std::{boxed::Box, sync::Arc};
+use alloc::{boxed::Box, sync::Arc};
 
 mod builder;
 mod exports;

crates/wasmi/src/lib.rs

@@ -79,9 +79,7 @@
 )]
 #![recursion_limit = "750"]
 
-#[cfg(not(feature = "std"))]
-extern crate alloc as std;
-
+extern crate alloc;
 #[cfg(feature = "std")]
 extern crate std;
 

crates/wasmi/src/linker.rs

@@ -23,15 +23,15 @@ use crate::{
     TableType,
     Val,
 };
-use core::{
-    fmt::{self, Debug, Display},
-    marker::PhantomData,
-};
-use std::{
+use alloc::{
     collections::{btree_map::Entry, BTreeMap},
     sync::Arc,
     vec::Vec,
 };
+use core::{
+    fmt::{self, Debug, Display},
+    marker::PhantomData,
+};
 
 /// An error that may occur upon operating with [`Linker`] instances.
 #[derive(Debug)]