perf: avoid unnecessary source map creation (#11773)

Author: CPunisher

crates/rspack_javascript_compiler/src/compiler/stringify.rs

@@ -4,9 +4,9 @@ use rspack_error::Result;
 use rspack_sources::{Mapping, OriginalLocation, encode_mappings};
 use rustc_hash::FxHashMap;
 use swc_core::{
-  base::{config::JsMinifyFormatOptions, sourcemap},
+  base::sourcemap,
   common::{
-    BytePos, FileName, SourceMap as SwcSourceMap, Spanned, comments::Comments,
+    BytePos, FileName, SourceMap as SwcSourceMap, comments::Comments,
     source_map::SourceMapGenConfig,
   },
   ecma::{
@@ -21,19 +21,6 @@ use swc_core::{
 };
 
 use super::{JavaScriptCompiler, TransformOutput};
-use crate::ast::Ast;
-
-#[derive(Default, Clone, Debug)]
-pub struct CodegenOptions<'a> {
-  pub target: Option<EsVersion>,
-  pub source_map_config: SourceMapConfig,
-  pub input_source_map: Option<&'a sourcemap::SourceMap>,
-  pub keep_comments: Option<bool>,
-  pub minify: Option<bool>,
-  pub ascii_only: Option<bool>,
-  pub inline_script: Option<bool>,
-  pub emit_assert_for_import_attributes: Option<bool>,
-}
 
 #[derive(Default, Clone, Debug)]
 pub struct SourceMapConfig {
@@ -80,41 +67,6 @@ pub struct PrintOptions<'a> {
 }
 
 impl JavaScriptCompiler {
-  pub fn stringify(&self, ast: &Ast, options: CodegenOptions) -> Result<TransformOutput> {
-    ast.visit(|program, context| {
-      let keep_comments = options.keep_comments;
-      let target = options.target.unwrap_or(EsVersion::latest());
-      let source_map_config = options.source_map_config;
-      let minify = options.minify.unwrap_or_default();
-      let format_opt = JsMinifyFormatOptions {
-        inline_script: options.inline_script.unwrap_or(true),
-        ascii_only: options.ascii_only.unwrap_or_default(),
-        emit_assert_for_import_attributes: options
-          .emit_assert_for_import_attributes
-          .unwrap_or_default(),
-        ..Default::default()
-      };
-
-      let span = program.program.span();
-      let print_options = PrintOptions {
-        source_len: span.hi.0.saturating_sub(span.lo.0),
-        source_map: context.source_map.clone(),
-        target,
-        source_map_config,
-        input_source_map: options.input_source_map,
-        minify,
-        comments: keep_comments
-          .unwrap_or_default()
-          .then(|| program.comments.as_ref().map(|c| c as &dyn Comments))
-          .flatten(),
-        preamble: &format_opt.preamble,
-        ascii_only: format_opt.ascii_only,
-        inline_script: format_opt.inline_script,
-      };
-      self.print(program.get_inner_program(), print_options)
-    })
-  }
-
   pub fn print(&self, node: &SwcProgram, options: PrintOptions<'_>) -> Result<TransformOutput> {
     let PrintOptions {
       source_len,

crates/rspack_loader_lightningcss/src/lib.rs

@@ -170,39 +170,39 @@ impl LightningCssLoader {
       })
       .to_rspack_result()?;
 
-    let enable_sourcemap = loader_context.context.module_source_map_kind.enabled();
-
-    let mut source_map = loader_context
-      .source_map()
-      .map(|input_source_map| -> Result<_> {
-        let mut sm = parcel_sourcemap::SourceMap::new(
-          input_source_map
-            .source_root()
-            .unwrap_or(&loader_context.context.options.context),
-        );
-        sm.add_source(&filename);
-        sm.set_source_content(0, &content_str).to_rspack_result()?;
-        Ok(sm)
-      })
-      .transpose()?
-      .unwrap_or_else(|| {
-        let mut source_map =
-          parcel_sourcemap::SourceMap::new(&loader_context.context.options.context);
-        let source_idx = source_map.add_source(&filename);
-        source_map
-          .set_source_content(source_idx as usize, &content_str)
-          .expect("should set source content");
-        source_map
-      });
+    let mut source_map = if loader_context.context.module_source_map_kind.enabled() {
+      Some(
+        loader_context
+          .source_map()
+          .map(|input_source_map| -> Result<_> {
+            let mut sm = parcel_sourcemap::SourceMap::new(
+              input_source_map
+                .source_root()
+                .unwrap_or(&loader_context.context.options.context),
+            );
+            sm.add_source(&filename);
+            sm.set_source_content(0, &content_str).to_rspack_result()?;
+            Ok(sm)
+          })
+          .transpose()?
+          .unwrap_or_else(|| {
+            let mut source_map =
+              parcel_sourcemap::SourceMap::new(&loader_context.context.options.context);
+            let source_idx = source_map.add_source(&filename);
+            source_map
+              .set_source_content(source_idx as usize, &content_str)
+              .expect("should set source content");
+            source_map
+          }),
+      )
+    } else {
+      None
+    };
 
     let content = stylesheet
       .to_css(PrinterOptions {
         minify: self.config.minify.unwrap_or(false),
-        source_map: if enable_sourcemap {
-          Some(&mut source_map)
-        } else {
-          None
-        },
+        source_map: source_map.as_mut(),
         project_root: None,
         targets,
         analyze_dependencies: None,
@@ -220,7 +220,7 @@ impl LightningCssLoader {
       })
       .to_rspack_result_with_message(|e| format!("failed to generate css: {e}"))?;
 
-    if enable_sourcemap {
+    if let Some(source_map) = source_map {
       let mappings = encode_mappings(source_map.get_mappings().iter().map(|mapping| Mapping {
         generated_line: mapping.generated_line,
         generated_column: mapping.generated_column,

crates/rspack_loader_swc/src/lib.rs

@@ -67,10 +67,15 @@ impl SwcLoader {
           .transform
           .merge(MergingOption::from(Some(transform)));
       }
-      if let Some(pre_source_map) = loader_context.source_map().cloned()
-        && let Ok(source_map) = pre_source_map.to_json()
-      {
-        swc_options.config.input_source_map = Some(InputSourceMap::Str(source_map))
+
+      if loader_context.context.module_source_map_kind.enabled() {
+        if let Some(pre_source_map) = loader_context.source_map().cloned()
+          && let Ok(source_map) = pre_source_map.to_json()
+        {
+          swc_options.config.input_source_map = Some(InputSourceMap::Str(source_map))
+        }
+      } else {
+        swc_options.config.input_source_map = Some(InputSourceMap::Bool(false));
       }
       swc_options.filename = resource_path.as_str().to_string();
       swc_options.source_file_name = Some(resource_path.as_str().to_string());