perf(allocator): Use std instead of allocator-api2 (#9281)

**Description:**

`std` is faster.

crates/swc_allocator/Cargo.toml

@@ -15,13 +15,12 @@ version       = "0.1.7"
 
 [features]
 default = ["scoped"]
-nightly = []
+nightly = ["bumpalo/allocator_api"]
 rkyv    = ["dep:rkyv"]
 scoped  = ["nightly"]
-serde   = ["dep:serde", "dep:serde_derive", "allocator-api2/serde"]
+serde   = ["dep:serde"]
 
 [dependencies]
-allocator-api2 = { workspace = true }
 bumpalo = { workspace = true, features = [
   "boxed",
   "collections",
@@ -30,7 +29,6 @@ bumpalo = { workspace = true, features = [
 ptr_meta = { workspace = true }
 rkyv = { workspace = true, optional = true }
 serde = { workspace = true, optional = true }
-serde_derive = { workspace = true, optional = true }
 triomphe = { workspace = true }
 
 

crates/swc_allocator/src/alloc.rs

@@ -1,16 +1,18 @@
-use std::{
-    alloc::Layout,
-    cell::Cell,
-    mem::transmute,
-    ops::{Deref, DerefMut},
-    ptr::NonNull,
-};
-
-use allocator_api2::alloc::AllocError;
+#[cfg(feature = "nightly")]
+use std::alloc::{AllocError, Layout};
+#[cfg(feature = "scoped")]
+use std::cell::Cell;
+#[cfg(feature = "scoped")]
+use std::mem::transmute;
+use std::ops::{Deref, DerefMut};
+#[cfg(feature = "nightly")]
+use std::ptr::NonNull;
+
 use bumpalo::Bump;
 
 use crate::FastAlloc;
 
+#[cfg(feature = "scoped")]
 thread_local! {
   static ALLOC: Cell<Option<&'static Allocator>> = const { Cell::new(None) };
 }
@@ -22,11 +24,13 @@ pub struct Allocator {
 }
 
 pub struct AllocGuard {
+    #[cfg(feature = "scoped")]
     orig: Option<&'static Allocator>,
 }
 
 impl Drop for AllocGuard {
     fn drop(&mut self) {
+        #[cfg(feature = "scoped")]
         ALLOC.set(self.orig.take());
     }
 }
@@ -39,15 +43,21 @@ impl Allocator {
     /// [Allocator] must outlive [crate::boxed::Box] and [crate::vec::Vec]
     /// created while the guard is active.
     pub unsafe fn guard(&self) -> AllocGuard {
+        #[cfg(feature = "scoped")]
         let orig = ALLOC.get();
 
+        #[cfg(feature = "scoped")]
         let s = unsafe {
             // Safery: We are using a scoped API
             transmute::<&Allocator, &'static Allocator>(self)
         };
 
+        #[cfg(feature = "scoped")]
         ALLOC.set(Some(s));
-        AllocGuard { orig }
+        AllocGuard {
+            #[cfg(feature = "scoped")]
+            orig,
+        }
     }
 }
 
@@ -66,27 +76,24 @@ impl Default for FastAlloc {
 
 impl FastAlloc {
     /// `true` is passed to `f` if the box is allocated with a custom allocator.
-    fn with_allocator<T>(
-        &self,
-        f: impl FnOnce(&dyn allocator_api2::alloc::Allocator, bool) -> T,
-    ) -> T {
+    #[cfg(feature = "nightly")]
+    fn with_allocator<T>(&self, f: impl FnOnce(&dyn std::alloc::Allocator, bool) -> T) -> T {
         #[cfg(feature = "scoped")]
         if let Some(arena) = &self.alloc {
-            return f(
-                (&&arena.alloc) as &dyn allocator_api2::alloc::Allocator,
-                true,
-            );
+            return f((&&arena.alloc) as &dyn std::alloc::Allocator, true);
         }
 
-        f(&allocator_api2::alloc::Global, false)
+        f(&std::alloc::Global, false)
     }
 }
 
+#[cfg(feature = "nightly")]
 fn mark_ptr_as_arena_mode(ptr: NonNull<[u8]>) -> NonNull<[u8]> {
     ptr
 }
 
-unsafe impl allocator_api2::alloc::Allocator for FastAlloc {
+#[cfg(feature = "nightly")]
+unsafe impl std::alloc::Allocator for FastAlloc {
     #[inline]
     fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
         self.with_allocator(|a, is_arena_mode| {
@@ -121,7 +128,7 @@ unsafe impl allocator_api2::alloc::Allocator for FastAlloc {
             return;
         }
 
-        allocator_api2::alloc::Global.deallocate(ptr, layout)
+        std::alloc::Global.deallocate(ptr, layout)
     }
 
     #[inline]

crates/swc_allocator/src/boxed/mod.rs

@@ -19,7 +19,7 @@ mod serde;
 /// Faster alterantive for [`std::boxed::Box`].
 #[repr(transparent)]
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Box<T: ?Sized>(pub(crate) allocator_api2::boxed::Box<T, FastAlloc>);
+pub struct Box<T: ?Sized>(pub(crate) std::boxed::Box<T, FastAlloc>);
 
 impl<T> From<T> for Box<T> {
     #[inline(always)]
@@ -28,9 +28,9 @@ impl<T> From<T> for Box<T> {
     }
 }
 
-impl<T: ?Sized> From<allocator_api2::boxed::Box<T, FastAlloc>> for Box<T> {
+impl<T: ?Sized> From<std::boxed::Box<T, FastAlloc>> for Box<T> {
     #[inline(always)]
-    fn from(v: allocator_api2::boxed::Box<T, FastAlloc>) -> Self {
+    fn from(v: std::boxed::Box<T, FastAlloc>) -> Self {
         Box(v)
     }
 }
@@ -76,12 +76,12 @@ impl<T> Box<T> {
     /// ```
     #[inline(always)]
     pub fn new_in(value: T, alloc: FastAlloc) -> Self {
-        Self(allocator_api2::boxed::Box::new_in(value, alloc))
+        Self(std::boxed::Box::new_in(value, alloc))
     }
 
     /// Moves the value out of the box.
     pub fn unbox(self) -> T {
-        allocator_api2::boxed::Box::into_inner(self.0)
+        std::boxed::Box::into_inner(self.0)
     }
 }
 
@@ -128,10 +128,7 @@ impl<T: ?Sized> Box<T> {
     /// [memory layout]: self#memory-layout
     /// [`Layout`]: crate::Layout
     pub unsafe fn from_raw(raw: *mut T) -> Self {
-        Self(allocator_api2::boxed::Box::from_raw_in(
-            raw,
-            FastAlloc::default(),
-        ))
+        Self(std::boxed::Box::from_raw_in(raw, FastAlloc::default()))
     }
 
     /// Consumes the `Box`, returning a wrapped raw pointer.
@@ -182,7 +179,7 @@ impl<T: ?Sized> Box<T> {
     ///
     /// [memory layout]: self#memory-layout
     pub fn into_raw(b: Self) -> *mut T {
-        allocator_api2::boxed::Box::into_raw(b.0)
+        std::boxed::Box::into_raw(b.0)
     }
 
     /// Converts a `Box<T>` into a `Pin<Box<T>>`. If `T` does not implement

crates/swc_allocator/src/boxed/serde.rs

@@ -22,6 +22,6 @@ where
     where
         D: Deserializer<'de>,
     {
-        Ok(Box(allocator_api2::boxed::Box::deserialize(deserializer)?))
+        Ok(Box::new(T::deserialize(deserializer)?))
     }
 }

crates/swc_allocator/src/lib.rs

@@ -29,7 +29,7 @@
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(
     feature = "nightly",
-    feature(allocator_api, fundamental, with_negative_coherence)
+    feature(allocator_api, fundamental, with_negative_coherence, box_into_inner)
 )]
 #![deny(missing_docs)]
 #![allow(clippy::derivable_impls)]
@@ -66,9 +66,9 @@ pub mod maybe {
 ///
 /// # Misc
 ///
-/// It implements [`allocator_api2::alloc::Allocator`]. So it can be used as the
-/// second argument for [`allocator_api2::boxed::Box`] and
-/// [`allocator_api2::vec::Vec`]. But you should prefer using
+/// It implements [`std::alloc::Allocator`]. So it can be used as the
+/// second argument for [`std::boxed::Box`] and
+/// [`std::vec::Vec`]. But you should prefer using
 /// [`crate::boxed::Box`] and [`crate::vec::Vec`], which is a wrapper around the
 /// original types.
 #[derive(Clone, Copy)]