refactor(traverse): simplify pointer manipulation and improve readabi…

…lity
oxc-project · Feb 16, 2025 · 4346b84 · 4346b84
1 parent 19fdf89
commit 4346b84
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Showing 4 changed files with 1,423 additions and 5,329 deletions.
diff --git a/crates/oxc_traverse/scripts/lib/ancestor.mjs b/crates/oxc_traverse/scripts/lib/ancestor.mjs
@@ -14,15 +14,8 @@ export default function generateAncestorsCode(types) {
   for (const type of Object.values(types)) {
     if (type.kind === 'enum') continue;
 
-    const typeSnakeName = camelToSnake(type.name),
-      typeScreamingName = typeSnakeName.toUpperCase();
-    let offsetCode = '';
-    for (const field of type.fields) {
-      const offsetVarName = `OFFSET_${typeScreamingName}_${field.name.toUpperCase()}`;
-      field.offsetVarName = offsetVarName;
-      offsetCode += `pub(crate) const ${offsetVarName}: usize = ` +
-        `offset_of!(${type.name}, ${field.rawName});\n`;
-    }
+    const typeSnakeName = camelToSnake(type.name);
+
 
     const variantNames = [];
     let thisAncestorTypes = '';
@@ -39,10 +32,7 @@ export default function generateAncestorsCode(types) {
           #[inline]
           pub fn ${otherField.rawName}(self) -> &'t ${otherField.rawTypeName} {
             unsafe {
-              &*(
-                (self.0 as *const u8).add(${otherField.offsetVarName})
-                as *const ${otherField.rawTypeName}
-              )
+              &*from_ref(&(*self.0).${otherField.rawName}) 
             }
           }
         `;
@@ -89,7 +79,6 @@ export default function generateAncestorsCode(types) {
 
     if (variantNames.length > 0) {
       ancestorTypes += `
-        ${offsetCode}
         ${thisAncestorTypes}
       `;
 
@@ -119,7 +108,7 @@ export default function generateAncestorsCode(types) {
       clippy::needless_lifetimes
     )]
 
-    use std::{cell::Cell, marker::PhantomData, mem::offset_of};
+    use std::{cell::Cell, marker::PhantomData, ptr::from_ref};
 
     use oxc_allocator::{Address, Box, GetAddress, Vec};
     use oxc_ast::ast::*;

diff --git a/crates/oxc_traverse/scripts/lib/walk.mjs b/crates/oxc_traverse/scripts/lib/walk.mjs
@@ -29,11 +29,10 @@ export default function generateWalkFunctionsCode(types) {
       clippy::cast_ptr_alignment
     )]
 
-    use std::{cell::Cell, marker::PhantomData};
+    use std::{marker::PhantomData, ptr::from_mut};
 
     use oxc_allocator::Vec;
     use oxc_ast::ast::*;
-    use oxc_syntax::scope::ScopeId;
 
     use crate::{ancestor::{self, AncestorType}, Ancestor, Traverse, TraverseCtx};
 
@@ -122,7 +121,7 @@ function generateWalkForStruct(type, types) {
 
     enterScopeCode = `
       let previous_scope_id = ctx.current_scope_id();
-      let current_scope_id = (*(${makeFieldCode(scopeIdField)})).get().unwrap();
+      let current_scope_id = ${makeFieldCode(scopeIdField)}.get().unwrap();
       ctx.set_current_scope_id(current_scope_id);
     `;
 
@@ -205,7 +204,7 @@ function generateWalkForStruct(type, types) {
       return `
         ${scopeCode}
         ${tagCode}
-        if let Some(field) = &mut *(${fieldCode}) {
+        if let Some(field) = &mut ${fieldCode} {
           ${retagCode}
           ${walkCode}
         }
@@ -216,18 +215,18 @@ function generateWalkForStruct(type, types) {
       let walkVecCode;
       if (field.wrappers.length === 1 && field.innerTypeName === 'Statement') {
         // Special case for `Vec<Statement>`
-        walkVecCode = `walk_statements(traverser, ${fieldCode}, ctx);`;
+        walkVecCode = `walk_statements(traverser, from_mut(&mut ${fieldCode}), ctx);`;
       } else {
         let walkCode = `${fieldWalkName}(traverser, item as *mut _, ctx);`,
           iteratorCode = '';
         if (field.wrappers.length === 2 && field.wrappers[1] === 'Option') {
-          iteratorCode = `(*(${fieldCode})).iter_mut().flatten()`;
+          iteratorCode = `${fieldCode}.iter_mut().flatten()`;
         } else {
           assert(
             field.wrappers.length === 1,
             `Cannot handle struct field with type ${field.type}`,
           );
-          iteratorCode = `&mut *(${fieldCode})`;
+          iteratorCode = `&mut ${fieldCode}`;
         }
         walkVecCode = `
           for item in ${iteratorCode} {
@@ -247,7 +246,7 @@ function generateWalkForStruct(type, types) {
       return `
         ${scopeCode}
         ${tagCode || retagCode}
-        ${fieldWalkName}(traverser, (&mut **(${fieldCode})) as *mut _, ctx);
+        ${fieldWalkName}(traverser, from_mut(&mut *(${fieldCode})), ctx);
       `;
     }
 
@@ -256,7 +255,7 @@ function generateWalkForStruct(type, types) {
     return `
       ${scopeCode}
       ${tagCode || retagCode}
-      ${fieldWalkName}(traverser, ${fieldCode}, ctx);
+      ${fieldWalkName}(traverser, from_mut(&mut ${fieldCode}), ctx);
     `;
   });
 
@@ -278,7 +277,7 @@ function generateWalkForStruct(type, types) {
 }
 
 function makeFieldCode(field) {
-  return `(node as *mut u8).add(ancestor::${field.offsetVarName}) as *mut ${field.typeName}`;
+  return `(*node).${field.name}`;
 }
 
 /**