refactor(allocator): store allocation pointer in metadata

Author: overlookmotel

crates/oxc_allocator/src/generated/assert_layouts.rs

@@ -9,26 +9,28 @@ use crate::*;
 
 #[cfg(target_pointer_width = "64")]
 const _: () = {
-    // Padding: 2 bytes
-    assert!(size_of::<RawTransferMetadata2>() == 16);
-    assert!(align_of::<RawTransferMetadata2>() == 4);
-    assert!(offset_of!(RawTransferMetadata2, data_offset) == 0);
-    assert!(offset_of!(RawTransferMetadata2, is_ts) == 12);
-    assert!(offset_of!(RawTransferMetadata2, id) == 4);
-    assert!(offset_of!(RawTransferMetadata2, can_be_freed) == 13);
-    assert!(offset_of!(RawTransferMetadata2, _padding) == 8);
+    // Padding: 6 bytes
+    assert!(size_of::<RawTransferMetadata2>() == 32);
+    assert!(align_of::<RawTransferMetadata2>() == 8);
+    assert!(offset_of!(RawTransferMetadata2, data_offset) == 16);
+    assert!(offset_of!(RawTransferMetadata2, is_ts) == 24);
+    assert!(offset_of!(RawTransferMetadata2, id) == 20);
+    assert!(offset_of!(RawTransferMetadata2, can_be_freed) == 25);
+    assert!(offset_of!(RawTransferMetadata2, alloc_ptr) == 8);
+    assert!(offset_of!(RawTransferMetadata2, _padding) == 0);
 };
 
 #[cfg(target_pointer_width = "32")]
 const _: () = {
     // Padding: 2 bytes
-    assert!(size_of::<RawTransferMetadata2>() == 16);
-    assert!(align_of::<RawTransferMetadata2>() == 4);
-    assert!(offset_of!(RawTransferMetadata2, data_offset) == 0);
-    assert!(offset_of!(RawTransferMetadata2, is_ts) == 12);
-    assert!(offset_of!(RawTransferMetadata2, id) == 4);
-    assert!(offset_of!(RawTransferMetadata2, can_be_freed) == 13);
-    assert!(offset_of!(RawTransferMetadata2, _padding) == 8);
+    assert!(size_of::<RawTransferMetadata2>() == 24);
+    assert!(align_of::<RawTransferMetadata2>() == 8);
+    assert!(offset_of!(RawTransferMetadata2, data_offset) == 12);
+    assert!(offset_of!(RawTransferMetadata2, is_ts) == 20);
+    assert!(offset_of!(RawTransferMetadata2, id) == 16);
+    assert!(offset_of!(RawTransferMetadata2, can_be_freed) == 21);
+    assert!(offset_of!(RawTransferMetadata2, alloc_ptr) == 8);
+    assert!(offset_of!(RawTransferMetadata2, _padding) == 0);
 };
 
 #[cfg(not(any(target_pointer_width = "64", target_pointer_width = "32")))]

crates/oxc_allocator/src/pool_fixed_size.rs

@@ -125,16 +125,25 @@ pub struct RawTransferMetadata2 {
     /// * Also be set to `true` if `FixedSizeAllocator` is dropped on Rust side.
     ///   Memory will be freed in finalizer when JS garbage collector collects the buffer.
     pub(crate) can_be_freed: AtomicBool,
-    /// Padding to pad struct to size 16.
-    pub(crate) _padding: u32,
+    /// Pointer to start of original allocation backing the `Allocator`.
+    pub(crate) alloc_ptr: NonNull<u8>,
+    /// Padding to pad struct to size 32.
+    pub(crate) _padding: u64,
 }
 use RawTransferMetadata2 as RawTransferMetadata;
 
 const METADATA_SIZE: usize = size_of::<RawTransferMetadata>();
 
 impl RawTransferMetadata {
-    fn new(id: u32) -> Self {
-        Self { data_offset: 0, is_ts: false, id, can_be_freed: AtomicBool::new(true), _padding: 0 }
+    fn new(id: u32, alloc_ptr: NonNull<u8>) -> Self {
+        Self {
+            data_offset: 0,
+            is_ts: false,
+            id,
+            can_be_freed: AtomicBool::new(true),
+            alloc_ptr,
+            _padding: 0,
+        }
     }
 }
 
@@ -175,8 +184,6 @@ const ALLOC_LAYOUT: Layout = match Layout::from_size_align(ALLOC_SIZE, ALLOC_ALI
 pub struct FixedSizeAllocator {
     /// `Allocator` which utilizes part of the original allocation
     allocator: ManuallyDrop<Allocator>,
-    /// Pointer to start of original allocation
-    alloc_ptr: NonNull<u8>,
 }
 
 impl FixedSizeAllocator {
@@ -215,14 +222,14 @@ impl FixedSizeAllocator {
         let allocator = unsafe { Allocator::from_raw_parts(chunk_ptr, CHUNK_SIZE) };
 
         // Store metadata after allocator chunk
-        let metadata = RawTransferMetadata::new(id);
+        let metadata = RawTransferMetadata::new(id, alloc_ptr);
         // SAFETY: `chunk_ptr` is at least `BUFFER_SIZE` bytes from the end of the allocation.
         // `CHUNK_SIZE` had the size of `RawTransferMetadata` subtracted from it.
         // So there is space within the allocation for `RawTransferMetadata` after the `Allocator`'s chunk.
         unsafe { chunk_ptr.add(CHUNK_SIZE).cast::<RawTransferMetadata>().write(metadata) };
 
         // Store pointer to original allocation, so it can be used to deallocate in `drop`
-        Self { allocator: ManuallyDrop::new(allocator), alloc_ptr }
+        Self { allocator: ManuallyDrop::new(allocator) }
     }
 
     /// Reset this [`FixedSizeAllocator`].
@@ -245,8 +252,17 @@ impl FixedSizeAllocator {
 
 impl Drop for FixedSizeAllocator {
     fn drop(&mut self) {
+        // Get pointer to start of allocation backing this `FixedSizeAllocator`
+        let alloc_ptr = {
+            let metadata_ptr = self.allocator.end_ptr().cast::<RawTransferMetadata>();
+            // SAFETY: `FixedSizeAllocator` is being dropped, so no other references to data in it may exist.
+            // `FixedSizeAllocator::new` wrote `RawTransferMetadata` to the location pointed to by `end_ptr`.
+            let metadata = unsafe { metadata_ptr.as_ref() };
+            metadata.alloc_ptr
+        };
+
         // SAFETY: Originally allocated from `System` allocator at `alloc_ptr`, with layout `ALLOC_LAYOUT`
-        unsafe { System.dealloc(self.alloc_ptr.as_ptr(), ALLOC_LAYOUT) }
+        unsafe { System.dealloc(alloc_ptr.as_ptr(), ALLOC_LAYOUT) }
     }
 }
 

crates/oxc_ast_macros/src/generated/structs.rs

@@ -135,7 +135,7 @@ pub static STRUCTS: phf::Map<&'static str, StructDetails> = ::phf::Map {
         ("Decorator", StructDetails { field_order: None }),
         ("CharacterClass", StructDetails { field_order: Some(&[0, 2, 3, 4, 1]) }),
         ("TemplateElementValue", StructDetails { field_order: None }),
-        ("RawTransferMetadata", StructDetails { field_order: Some(&[0, 3, 1, 4, 2]) }),
+        ("RawTransferMetadata", StructDetails { field_order: Some(&[2, 4, 3, 5, 1, 0]) }),
         ("TSTypeParameter", StructDetails { field_order: None }),
         ("SourceType", StructDetails { field_order: None }),
         ("ErrorLabel", StructDetails { field_order: Some(&[1, 0]) }),
@@ -266,7 +266,7 @@ pub static STRUCTS: phf::Map<&'static str, StructDetails> = ::phf::Map {
         ("ImportAttribute", StructDetails { field_order: None }),
         ("TSConditionalType", StructDetails { field_order: None }),
         ("TSNamespaceExportDeclaration", StructDetails { field_order: None }),
-        ("RawTransferMetadata2", StructDetails { field_order: Some(&[0, 3, 1, 4, 2]) }),
+        ("RawTransferMetadata2", StructDetails { field_order: Some(&[2, 4, 3, 5, 1, 0]) }),
         ("AssignmentTargetWithDefault", StructDetails { field_order: None }),
         ("RegExpLiteral", StructDetails { field_order: None }),
         ("CapturingGroup", StructDetails { field_order: None }),

napi/parser/generated/constants.js

@@ -4,7 +4,7 @@
 const BUFFER_SIZE = 2147483632,
   BUFFER_ALIGN = 4294967296,
   DATA_POINTER_POS_32 = 536870904,
-  IS_TS_FLAG_POS = 2147483628,
+  IS_TS_FLAG_POS = 2147483624,
   PROGRAM_OFFSET = 0;
 
 module.exports = {

napi/parser/generated/deserialize/js.js

@@ -4028,6 +4028,15 @@ function deserializeBool(pos) {
   return uint8[pos] === 1;
 }
 
+function deserializeU8(pos) {
+  return uint8[pos];
+}
+
+function deserializeU64(pos) {
+  const pos32 = pos >> 2;
+  return uint32[pos32] + uint32[pos32 + 1] * 4294967296;
+}
+
 function deserializeStr(pos) {
   const pos32 = pos >> 2,
     len = uint32[pos32 + 2];
@@ -4859,10 +4868,6 @@ function deserializeF64(pos) {
   return float64[pos >> 3];
 }
 
-function deserializeU8(pos) {
-  return uint8[pos];
-}
-
 function deserializeBoxJSXOpeningElement(pos) {
   return deserializeJSXOpeningElement(uint32[pos >> 2]);
 }
@@ -5243,11 +5248,6 @@ function deserializeOptionNameSpan(pos) {
   return deserializeNameSpan(pos);
 }
 
-function deserializeU64(pos) {
-  const pos32 = pos >> 2;
-  return uint32[pos32] + uint32[pos32 + 1] * 4294967296;
-}
-
 function deserializeOptionU64(pos) {
   if (uint8[pos] === 0) return null;
   return deserializeU64(pos + 8);

napi/parser/generated/deserialize/ts.js

@@ -4159,6 +4159,15 @@ function deserializeBool(pos) {
   return uint8[pos] === 1;
 }
 
+function deserializeU8(pos) {
+  return uint8[pos];
+}
+
+function deserializeU64(pos) {
+  const pos32 = pos >> 2;
+  return uint32[pos32] + uint32[pos32 + 1] * 4294967296;
+}
+
 function deserializeStr(pos) {
   const pos32 = pos >> 2,
     len = uint32[pos32 + 2];
@@ -4990,10 +4999,6 @@ function deserializeF64(pos) {
   return float64[pos >> 3];
 }
 
-function deserializeU8(pos) {
-  return uint8[pos];
-}
-
 function deserializeBoxJSXOpeningElement(pos) {
   return deserializeJSXOpeningElement(uint32[pos >> 2]);
 }
@@ -5374,11 +5379,6 @@ function deserializeOptionNameSpan(pos) {
   return deserializeNameSpan(pos);
 }
 
-function deserializeU64(pos) {
-  const pos32 = pos >> 2;
-  return uint32[pos32] + uint32[pos32 + 1] * 4294967296;
-}
-
 function deserializeOptionU64(pos) {
   if (uint8[pos] === 0) return null;
   return deserializeU64(pos + 8);

napi/parser/generated/lazy/constructors.js

@@ -12480,6 +12480,16 @@ function constructBool(pos, ast) {
   return ast.buffer[pos] === 1;
 }
 
+function constructU8(pos, ast) {
+  return ast.buffer[pos];
+}
+
+function constructU64(pos, ast) {
+  const { uint32 } = ast.buffer,
+    pos32 = pos >> 2;
+  return uint32[pos32] + uint32[pos32 + 1] * 4294967296;
+}
+
 function constructStr(pos, ast) {
   const pos32 = pos >> 2,
     { buffer } = ast,
@@ -13357,10 +13367,6 @@ function constructF64(pos, ast) {
   return ast.buffer.float64[pos >> 3];
 }
 
-function constructU8(pos, ast) {
-  return ast.buffer[pos];
-}
-
 function constructBoxJSXOpeningElement(pos, ast) {
   return new JSXOpeningElement(ast.buffer.uint32[pos >> 2], ast);
 }
@@ -13757,12 +13763,6 @@ function constructOptionNameSpan(pos, ast) {
   return new NameSpan(pos, ast);
 }
 
-function constructU64(pos, ast) {
-  const { uint32 } = ast.buffer,
-    pos32 = pos >> 2;
-  return uint32[pos32] + uint32[pos32 + 1] * 4294967296;
-}
-
 function constructOptionU64(pos, ast) {
   if (ast.buffer[pos] === 0) return null;
   return constructU64(pos + 8, ast);

napi/parser/src/generated/assert_layouts.rs

@@ -17,14 +17,15 @@ const _: () = {
     assert!(offset_of!(RawTransferData, module) == 152);
     assert!(offset_of!(RawTransferData, errors) == 256);
 
-    // Padding: 2 bytes
-    assert!(size_of::<RawTransferMetadata>() == 16);
-    assert!(align_of::<RawTransferMetadata>() == 4);
-    assert!(offset_of!(RawTransferMetadata, data_offset) == 0);
-    assert!(offset_of!(RawTransferMetadata, is_ts) == 12);
-    assert!(offset_of!(RawTransferMetadata, id) == 4);
-    assert!(offset_of!(RawTransferMetadata, can_be_freed) == 13);
-    assert!(offset_of!(RawTransferMetadata, _padding) == 8);
+    // Padding: 6 bytes
+    assert!(size_of::<RawTransferMetadata>() == 32);
+    assert!(align_of::<RawTransferMetadata>() == 8);
+    assert!(offset_of!(RawTransferMetadata, data_offset) == 16);
+    assert!(offset_of!(RawTransferMetadata, is_ts) == 24);
+    assert!(offset_of!(RawTransferMetadata, id) == 20);
+    assert!(offset_of!(RawTransferMetadata, can_be_freed) == 25);
+    assert!(offset_of!(RawTransferMetadata, alloc_ptr) == 8);
+    assert!(offset_of!(RawTransferMetadata, _padding) == 0);
 
     // Padding: 7 bytes
     assert!(size_of::<Error>() == 80);
@@ -78,13 +79,14 @@ const _: () = {
     assert!(offset_of!(RawTransferData, errors) == 172);
 
     // Padding: 2 bytes
-    assert!(size_of::<RawTransferMetadata>() == 16);
-    assert!(align_of::<RawTransferMetadata>() == 4);
-    assert!(offset_of!(RawTransferMetadata, data_offset) == 0);
-    assert!(offset_of!(RawTransferMetadata, is_ts) == 12);
-    assert!(offset_of!(RawTransferMetadata, id) == 4);
-    assert!(offset_of!(RawTransferMetadata, can_be_freed) == 13);
-    assert!(offset_of!(RawTransferMetadata, _padding) == 8);
+    assert!(size_of::<RawTransferMetadata>() == 24);
+    assert!(align_of::<RawTransferMetadata>() == 8);
+    assert!(offset_of!(RawTransferMetadata, data_offset) == 12);
+    assert!(offset_of!(RawTransferMetadata, is_ts) == 20);
+    assert!(offset_of!(RawTransferMetadata, id) == 16);
+    assert!(offset_of!(RawTransferMetadata, can_be_freed) == 21);
+    assert!(offset_of!(RawTransferMetadata, alloc_ptr) == 8);
+    assert!(offset_of!(RawTransferMetadata, _padding) == 0);
 
     // Padding: 3 bytes
     assert!(size_of::<Error>() == 44);

napi/parser/src/raw_transfer_types.rs

@@ -1,6 +1,9 @@
 #![cfg_attr(not(all(target_pointer_width = "64", target_endian = "little")), expect(dead_code))]
 
-use std::sync::{Arc, atomic::AtomicBool};
+use std::{
+    ptr::NonNull,
+    sync::{Arc, atomic::AtomicBool},
+};
 
 use rustc_hash::FxHashMap;
 
@@ -40,13 +43,22 @@ pub struct RawTransferMetadata {
     pub(crate) id: u32,
     /// Not used in this implementation. Only used by `oxc_allocator`.
     pub(crate) can_be_freed: AtomicBool,
-    /// Padding to pad struct to size 16.
-    pub(crate) _padding: u32,
+    /// Not used in this implementation. Only used by `oxc_allocator`.
+    pub(crate) alloc_ptr: NonNull<u8>,
+    /// Padding to pad struct to size 32.
+    pub(crate) _padding: u64,
 }
 
 impl RawTransferMetadata {
     pub fn new(data_offset: u32, is_ts: bool) -> Self {
-        Self { data_offset, is_ts, id: 0, can_be_freed: AtomicBool::new(false), _padding: 0 }
+        Self {
+            data_offset,
+            is_ts,
+            id: 0,
+            can_be_freed: AtomicBool::new(false),
+            alloc_ptr: NonNull::dangling(),
+            _padding: 0,
+        }
     }
 }