feat(traverse): support automatically variable hoisting during genera…

…ting bindings
oxc-project · Nov 22, 2024 · d1dbaa1 · d1dbaa1
1 parent 52784d2
commit d1dbaa1
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Showing 8 changed files with 364 additions and 1,228 deletions.
diff --git a/crates/oxc_transformer/src/jsx/refresh.rs b/crates/oxc_transformer/src/jsx/refresh.rs
@@ -576,14 +576,7 @@ impl<'a, 'ctx> ReactRefresh<'a, 'ctx> {
             arguments.push(function);
         }
 
-        // TODO: Handle var hoisted in ctx API
-        let target_scope_id = ctx
-            .scopes()
-            .ancestors(ctx.current_scope_id())
-            .find(|&scope_id| ctx.scopes().get_flags(scope_id).is_var())
-            .unwrap_or_else(|| ctx.current_scope_id());
-
-        let binding = ctx.generate_uid("s", target_scope_id, SymbolFlags::FunctionScopedVariable);
+        let binding = ctx.generate_uid_in_current_scope("s", SymbolFlags::FunctionScopedVariable);
 
         // _s();
         let call_expression = ctx.ast.statement_expression(

diff --git a/crates/oxc_traverse/scripts/lib/walk.mjs b/crates/oxc_traverse/scripts/lib/walk.mjs
@@ -109,11 +109,20 @@ function generateWalkForStruct(type, types) {
     // but we don't take that into account.
     // Visitor should not do that though, so maybe it's OK.
     // In final version, we should not make `scope_id` fields `Cell`s to prevent this.
+
+    // const Var = Self::Top.bits() | Self::Function.bits() | Self::ClassStaticBlock.bits() | Self::TsModuleBlock.bits();
+    let isVarHoistingScope = type.name == "Function" || ["Top", "Function", "ClassStaticBlock", "TsModuleBlock"]
+        .some(flag => scopeArgs.flags.includes(flag));
+
+console.log("isVarHoistingScope", type.name, isVarHoistingScope, scopeArgs);
     enterScopeCode = `
-      let previous_scope_id = ctx.current_scope_id();
-      ctx.set_current_scope_id((*(${makeFieldCode(scopeIdField)})).get().unwrap());
+        let previous_scope_id = ctx.current_scope_id();
+        ${isVarHoistingScope ? `let previous_var_hoisting_scope_id = ctx.scoping.current_var_hoisting_scope_id();` : ''}
+        let current_scope_id = (*(${makeFieldCode(scopeIdField)})).get().unwrap();
+        ctx.set_current_scope_id(current_scope_id, ${isVarHoistingScope ? "Some(current_scope_id)" : "None"});
     `;
-    exitScopeCode = `ctx.set_current_scope_id(previous_scope_id);`;
+
+    exitScopeCode = `ctx.set_current_scope_id(previous_scope_id, ${isVarHoistingScope ? "Some(previous_var_hoisting_scope_id)" : "None"} );`;
   }
 
   const fieldsCodes = visitedFields.map((field, index) => {

diff --git a/crates/oxc_traverse/src/context/mod.rs b/crates/oxc_traverse/src/context/mod.rs
@@ -3,8 +3,8 @@ use oxc_ast::{
     ast::{Expression, IdentifierReference, Statement},
     AstBuilder,
 };
-use oxc_semantic::{NodeId, ScopeTree, SymbolTable};
-use oxc_span::{Atom, CompactStr, Span, SPAN};
+use oxc_semantic::{ScopeTree, SymbolTable};
+use oxc_span::{Atom, CompactStr, Span};
 use oxc_syntax::{
     reference::{ReferenceFlags, ReferenceId},
     scope::{ScopeFlags, ScopeId},
@@ -356,12 +356,7 @@ impl<'a> TraverseCtx<'a> {
         // Get name for UID
         let name = self.generate_uid_name(name);
         let name_atom = self.ast.atom(&name);
-
-        // Add binding to scope
-        let symbol_id =
-            self.symbols_mut().create_symbol(SPAN, name.clone(), flags, scope_id, NodeId::DUMMY);
-        self.scopes_mut().add_binding(scope_id, name, symbol_id);
-
+        let symbol_id = self.scoping.add_binding(scope_id, name, flags);
         BoundIdentifier::new(name_atom, symbol_id)
     }
 
@@ -620,7 +615,11 @@ impl<'a> TraverseCtx<'a> {
 
     /// Shortcut for `ctx.scoping.set_current_scope_id`, to make `walk_*` methods less verbose.
     #[inline]
-    pub(crate) fn set_current_scope_id(&mut self, scope_id: ScopeId) {
-        self.scoping.set_current_scope_id(scope_id);
+    pub(crate) fn set_current_scope_id(
+        &mut self,
+        scope_id: ScopeId,
+        var_hoisting_scope_id: Option<ScopeId>,
+    ) {
+        self.scoping.set_current_scope_id(scope_id, var_hoisting_scope_id);
     }
 }
diff --git a/crates/oxc_traverse/src/context/scoping.rs b/crates/oxc_traverse/src/context/scoping.rs
@@ -26,6 +26,7 @@ pub struct TraverseScoping {
     symbols: SymbolTable,
     uid_names: Option<FxHashSet<CompactStr>>,
     current_scope_id: ScopeId,
+    current_var_hoisting_scope_id: ScopeId,
 }
 
 // Public methods
@@ -40,6 +41,12 @@ impl TraverseScoping {
         self.current_scope_id
     }
 
+    /// Get current scope ID
+    #[inline]
+    pub(crate) fn current_var_hoisting_scope_id(&self) -> ScopeId {
+        self.current_var_hoisting_scope_id
+    }
+
     /// Get current scope flags
     #[inline]
     pub fn current_scope_flags(&self) -> ScopeFlags {
@@ -164,6 +171,33 @@ impl TraverseScoping {
         self.scopes.delete_scope(scope_id);
     }
 
+    pub fn add_binding(
+        &mut self,
+        scope_id: ScopeId,
+        name: CompactStr,
+        flags: SymbolFlags,
+    ) -> SymbolId {
+        // println!(
+        //     "{name:?} {scope_id:?} {:?} {:?}",
+        //     self.scopes.get_flags(scope_id),
+        //     self.current_var_hoisting_scope_id
+        // );
+        let scope_id = if scope_id == self.current_var_hoisting_scope_id
+            || flags != SymbolFlags::FunctionScopedVariable
+            || self.scopes.get_flags(scope_id).is_var()
+        {
+            scope_id
+        } else {
+            self.current_var_hoisting_scope_id
+        };
+
+        let symbol_id =
+            self.symbols.create_symbol(SPAN, name.clone(), flags, scope_id, NodeId::DUMMY);
+        self.scopes.add_binding(scope_id, name, symbol_id);
+
+        symbol_id
+    }
+
     /// Generate binding.
     ///
     /// Creates a symbol with the provided name and flags and adds it to the specified scope.
@@ -174,8 +208,6 @@ impl TraverseScoping {
         flags: SymbolFlags,
     ) -> BoundIdentifier<'a> {
         let owned_name = name.to_compact_str();
-
-        // Add binding to scope
         let symbol_id =
             self.symbols.create_symbol(SPAN, owned_name.clone(), flags, scope_id, NodeId::DUMMY);
         self.scopes.add_binding(scope_id, owned_name, symbol_id);
@@ -388,13 +420,23 @@ impl TraverseScoping {
             uid_names: None,
             // Dummy value. Immediately overwritten in `walk_program`.
             current_scope_id: ScopeId::new(0),
+            // Dummy value. Immediately overwritten in `walk_program`.
+            current_var_hoisting_scope_id: ScopeId::new(0),
         }
     }
 
     /// Set current scope ID
     #[inline]
-    pub(crate) fn set_current_scope_id(&mut self, scope_id: ScopeId) {
+    pub(crate) fn set_current_scope_id(
+        &mut self,
+        scope_id: ScopeId,
+        var_hoisting_scope_id: Option<ScopeId>,
+    ) {
         self.current_scope_id = scope_id;
+        if let Some(var_hoisting_scope_id) = var_hoisting_scope_id {
+            self.current_var_hoisting_scope_id = var_hoisting_scope_id;
+        }
+        // println!("{:?} {:?} {:?}", var_hoisting_scope_id, scope_id, self.current_scope_flags());
     }
 
     /// Get `uid_names`.