feat(macros): Add #[swc_trace] (#3738)

Cargo.lock

@@ -3189,6 +3189,7 @@ dependencies = [
  "swc_ecma_transforms_testing",
  "swc_ecma_utils",
  "swc_ecma_visit",
+ "swc_trace_macro",
  "testing",
  "tracing",
 ]
@@ -3579,6 +3580,15 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "swc_trace_macro"
+version = "0.1.0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "swc_visit"
 version = "0.3.0"

crates/swc_ecma_transforms_compat/Cargo.toml

@@ -34,6 +34,7 @@ swc_ecma_transforms_classes = {version = "0.50.0", path = "../swc_ecma_transform
 swc_ecma_transforms_macros = {version = "0.3.0", path = "../swc_ecma_transforms_macros"}
 swc_ecma_utils = {version = "0.68.0", path = "../swc_ecma_utils"}
 swc_ecma_visit = {version = "0.54.0", path = "../swc_ecma_visit"}
+swc_trace_macro = {versio = "0.1.0", path = "../swc_trace_macro"}
 tracing = "0.1.31"
 
 [dev-dependencies]

crates/swc_ecma_transforms_compat/src/es2015/arrow.rs

@@ -7,6 +7,7 @@ use swc_ecma_utils::{
     prepend,
 };
 use swc_ecma_visit::{as_folder, noop_visit_mut_type, Fold, InjectVars, VisitMut, VisitMutWith};
+use swc_trace_macro::swc_trace;
 
 /// Compile ES2015 arrow functions to ES5
 ///
@@ -67,10 +68,10 @@ struct Arrow {
     hoister: FnEnvHoister,
 }
 
+#[swc_trace]
 impl VisitMut for Arrow {
     noop_visit_mut_type!();
 
-    #[tracing::instrument(level = "trace", skip_all)]
     fn visit_mut_class(&mut self, c: &mut Class) {
         if c.super_class.is_some() {
             self.in_subclass = true;
@@ -79,7 +80,6 @@ impl VisitMut for Arrow {
         self.in_subclass = false;
     }
 
-    #[tracing::instrument(level = "trace", skip_all)]
     fn visit_mut_constructor(&mut self, c: &mut Constructor) {
         c.params.visit_mut_children_with(self);
 
@@ -108,7 +108,6 @@ impl VisitMut for Arrow {
         }
     }
 
-    #[tracing::instrument(level = "trace", skip_all)]
     fn visit_mut_expr(&mut self, expr: &mut Expr) {
         match expr {
             Expr::Arrow(ArrowExpr {
@@ -167,12 +166,10 @@ impl VisitMut for Arrow {
         }
     }
 
-    #[tracing::instrument(level = "trace", skip_all)]
     fn visit_mut_function(&mut self, f: &mut Function) {
         f.visit_mut_children_with(self);
     }
 
-    #[tracing::instrument(level = "trace", skip_all)]
     fn visit_mut_module_items(&mut self, stmts: &mut Vec<ModuleItem>) {
         stmts.visit_mut_children_with(self);
 
@@ -183,7 +180,6 @@ impl VisitMut for Arrow {
         }
     }
 
-    #[tracing::instrument(level = "trace", skip_all)]
     fn visit_mut_stmts(&mut self, stmts: &mut Vec<Stmt>) {
         let old_rep = self.hoister.take();
 

crates/swc_trace_macro/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+authors = ["강동윤 <kdy1997.dev@gmail.com>"]
+description = "Proc macro for performance trace of swc"
+documentation = "https://rustdoc.swc.rs/swc_trace_macro/"
+edition = "2021"
+license = "Apache-2.0"
+name = "swc_trace_macro"
+repository = "https://github.com/swc-project/swc.git"
+version = "0.1.0"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1"
+quote = "1"
+syn = {version = "1", features = ["full"]}

crates/swc_trace_macro/src/lib.rs

@@ -0,0 +1,35 @@
+extern crate proc_macro;
+
+use quote::ToTokens;
+use syn::{parse_quote, AttrStyle, Attribute, ImplItem, ItemImpl};
+
+/// Utility proc macro to add `#[tracing::instrument(level = "trace",
+/// skip_all)]` to all methods in an impl block.
+///
+/// This attribute macro is typically applied on an `VisitMut` impl block.
+/// If this is applied, all implemented methods will annotated with the
+/// instrument annotation from `tracing`.
+#[proc_macro_attribute]
+pub fn swc_trace(
+    _args: proc_macro::TokenStream,
+    input: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+    let mut item = syn::parse::<ItemImpl>(input).expect("#[swc_trace] expects an impl block");
+
+    item.items.iter_mut().for_each(|item| {
+        // We only handle methods
+        if let ImplItem::Method(m) = item {
+            // #[tracing::instrument(level = "trace", skip_all)]
+            let attr = Attribute {
+                pound_token: Default::default(),
+                style: AttrStyle::Outer,
+                bracket_token: Default::default(),
+                path: parse_quote!(tracing::instrument),
+                tokens: parse_quote!((level = "trace", skip_all)),
+            };
+            m.attrs.push(attr);
+        }
+    });
+
+    item.to_token_stream().into()
+}