diff --git a/.cargo/config b/.cargo/config
index f3eb8d6e5a1..c1ea8d02bf4 100644
--- a/.cargo/config
+++ b/.cargo/config
@@ -1,6 +1,11 @@
 
 [build]
-rustflags = ["--cfg", "procmacro2_semver_exempt"] 
+rustflags = [
+    "--cfg", "procmacro2_semver_exempt",
+    "--cfg", "parallel_queries",
+]
+ 
 rustdocflags = [
     "--cfg", "procmacro2_semver_exempt",
+    "--cfg", "parallel_queries",
 ]
diff --git a/README.md b/README.md
index 8e339d93cbb..e38ae3c04ef 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ swc is rust port of [babel][] and [closure compiler][].
 Requires nightly version of [rust][].
 
 ```sh
-RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo install --git https://github.com/swc-project/swc.git
+RUSTFLAGS='--cfg procmacro2_semver_exempt --cfg parallel_queries' cargo install --git https://github.com/swc-project/swc.git
 ```
 
 # Features
diff --git a/common/src/errors/tests.rs b/common/src/errors/tests.rs
index b8e605e1319..c9351e99ed2 100644
--- a/common/src/errors/tests.rs
+++ b/common/src/errors/tests.rs
@@ -3,8 +3,8 @@ use crate::{FileLoader, FilePathMapping, SourceMap};
 use std::{
     io,
     path::{Path, PathBuf},
-    rc::Rc,
 };
+use sync::Lrc;
 use BytePos;
 use Span;
 
@@ -47,7 +47,7 @@ fn test() {
     let end_pos = file_map.end_pos - BytePos(1);
     let full = Span::new(start_pos, end_pos, Default::default());
 
-    let handler = Handler::with_tty_emitter(ColorConfig::Always, false, false, Some(Rc::new(cm)));
+    let handler = Handler::with_tty_emitter(ColorConfig::Always, false, false, Some(Lrc::new(cm)));
 
     ::syntax_pos::GLOBALS.set(&::syntax_pos::Globals::new(), || {
         DiagnosticBuilder::new_with_code(
diff --git a/common/src/lib.rs b/common/src/lib.rs
index c0d58ab39a5..26ab3dce757 100644
--- a/common/src/lib.rs
+++ b/common/src/lib.rs
@@ -17,6 +17,7 @@ pub use self::{
     pos::*,
 };
 pub use ast_node::{ast_node, Fold, FromVariant, Spanned};
+pub use rustc_data_structures::sync;
 use std::fmt::Debug;
 pub use syntax::source_map::{
     FileLines, FileLoader, FileName, FilePathMapping, SourceMap, SpanSnippetError,
diff --git a/ecmascript/codegen/src/lib.rs b/ecmascript/codegen/src/lib.rs
index 6528e28c81b..f60355b2572 100644
--- a/ecmascript/codegen/src/lib.rs
+++ b/ecmascript/codegen/src/lib.rs
@@ -21,9 +21,9 @@ use self::{
     text_writer::WriteJs,
     util::{SourceMapperExt, SpanExt, StartsWithAlphaNum},
 };
-use std::{collections::HashSet, io, rc::Rc};
+use std::{collections::HashSet, io};
 use swc_atoms::JsWord;
-use swc_common::{BytePos, SourceMap, Span, Spanned, SyntaxContext, DUMMY_SP};
+use swc_common::{sync::Lrc, BytePos, SourceMap, Span, Spanned, SyntaxContext, DUMMY_SP};
 use swc_ecma_ast::*;
 use swc_ecma_codegen_macros::emitter;
 
@@ -61,7 +61,7 @@ impl<'a, N: Node> Node for &'a N {
 
 pub struct Emitter<'a> {
     pub cfg: config::Config,
-    pub cm: Rc<SourceMap>,
+    pub cm: Lrc<SourceMap>,
     pub wr: Box<('a + WriteJs)>,
     pub handlers: Box<('a + Handlers)>,
     pub pos_of_leading_comments: HashSet<BytePos>,
@@ -1478,7 +1478,7 @@ impl<'a> Emitter<'a> {
 }
 
 fn get_text_of_node<T: Spanned>(
-    cm: &Rc<SourceMap>,
+    cm: &Lrc<SourceMap>,
     node: &T,
     _include_travia: bool,
 ) -> Option<String> {
diff --git a/ecmascript/codegen/src/tests.rs b/ecmascript/codegen/src/tests.rs
index 6c414bd9f22..35c66ae7a4e 100644
--- a/ecmascript/codegen/src/tests.rs
+++ b/ecmascript/codegen/src/tests.rs
@@ -19,7 +19,7 @@ impl Handlers for Noop {}
 
 struct Builder {
     cfg: Config,
-    cm: Rc<SourceMap>,
+    cm: Lrc<SourceMap>,
 }
 
 fn test() -> Builder {
@@ -27,7 +27,7 @@ fn test() -> Builder {
 
     Builder {
         cfg: Default::default(),
-        cm: Rc::new(src),
+        cm: Lrc::new(src),
     }
 }
 
diff --git a/ecmascript/codegen/src/text_writer/basic_impl.rs b/ecmascript/codegen/src/text_writer/basic_impl.rs
index b457d96d981..026020d97a1 100644
--- a/ecmascript/codegen/src/text_writer/basic_impl.rs
+++ b/ecmascript/codegen/src/text_writer/basic_impl.rs
@@ -1,10 +1,7 @@
 use super::{Result, WriteJs};
 use sourcemap::SourceMapBuilder;
-use std::{
-    io::{self, Write},
-    rc::Rc,
-};
-use swc_common::{SourceMap, Span};
+use std::io::{self, Write};
+use swc_common::{sync::Lrc, SourceMap, Span};
 
 ///
 /// -----
@@ -13,7 +10,7 @@ use swc_common::{SourceMap, Span};
 ///
 /// https://github.com/Microsoft/TypeScript/blob/45eaf42006/src/compiler/utilities.ts#L2548
 pub struct JsWriter<'a, W: Write> {
-    cm: Rc<SourceMap>,
+    cm: Lrc<SourceMap>,
     indent: usize,
     line_start: bool,
     line_count: usize,
@@ -26,7 +23,7 @@ pub struct JsWriter<'a, W: Write> {
 
 impl<'a, W: Write> JsWriter<'a, W> {
     pub fn new(
-        cm: Rc<SourceMap>,
+        cm: Lrc<SourceMap>,
         new_line: &'a str,
         wr: W,
         srcmap: &'a mut SourceMapBuilder,
diff --git a/ecmascript/codegen/src/util.rs b/ecmascript/codegen/src/util.rs
index 3cc8328f800..232caf3ef36 100644
--- a/ecmascript/codegen/src/util.rs
+++ b/ecmascript/codegen/src/util.rs
@@ -1,7 +1,7 @@
 use super::list::ListFormat;
-use std::rc::Rc;
 use swc_common::{
-    errors::SourceMapper, BytePos, SourceMap, SourceMapperDyn, Span, Spanned, SyntaxContext,
+    errors::SourceMapper, sync::Lrc, BytePos, SourceMap, SourceMapperDyn, Span, Spanned,
+    SyntaxContext,
 };
 use swc_ecma_ast::*;
 
@@ -127,12 +127,13 @@ impl SourceMapperExt for SourceMapper {
         self
     }
 }
-impl SourceMapperExt for Rc<SourceMapperDyn> {
+impl SourceMapperExt for Lrc<SourceMapperDyn> {
     fn get_code_map(&self) -> &SourceMapper {
         &**self
     }
 }
-impl SourceMapperExt for Rc<SourceMap> {
+
+impl SourceMapperExt for Lrc<SourceMap> {
     fn get_code_map(&self) -> &SourceMapper {
         &**self
     }
diff --git a/ecmascript/codegen/tests/test262.rs b/ecmascript/codegen/tests/test262.rs
index d90d47a8312..79b9b353c49 100644
--- a/ecmascript/codegen/tests/test262.rs
+++ b/ecmascript/codegen/tests/test262.rs
@@ -15,10 +15,9 @@ use std::{
     fs::{read_dir, File},
     io::{self, Read, Write},
     path::Path,
-    rc::Rc,
     sync::{Arc, RwLock},
 };
-use swc_common::{Fold, FoldWith, Span};
+use swc_common::{sync::Lrc, Fold, FoldWith, Span};
 use swc_ecma_ast::*;
 use swc_ecma_codegen::Emitter;
 use swc_ecma_parser::{Parser, Session, SourceFileInput};
@@ -158,7 +157,7 @@ fn error_tests(tests: &mut Vec<TestDescAndFn>) -> Result<(), io::Error> {
                     (&*src).into(),
                 );
 
-                let s: Rc<String> = src.src.as_ref().map(|s| s.clone()).unwrap();
+                let s: Lrc<String> = src.src.as_ref().map(|s| s.clone()).unwrap();
                 let mut src_map_builder = SourceMapBuilder::new(Some(&s));
                 {
                     let mut emitter = Emitter {
diff --git a/ecmascript/transforms/src/compat/helpers/mod.rs b/ecmascript/transforms/src/compat/helpers/mod.rs
index f5da6a1bb2a..aefe82d7de5 100644
--- a/ecmascript/transforms/src/compat/helpers/mod.rs
+++ b/ecmascript/transforms/src/compat/helpers/mod.rs
@@ -1,7 +1,6 @@
 use ast::*;
 use std::{
     ops::BitOr,
-    rc::Rc,
     sync::{
         atomic::{AtomicBool, Ordering},
         Arc,
@@ -9,6 +8,7 @@ use std::{
 };
 use swc_common::{
     errors::{ColorConfig, Handler},
+    sync::Lrc,
     FileName, Fold, SourceMap,
 };
 use swc_ecma_parser::{Parser, Session, SourceFileInput};
@@ -49,7 +49,7 @@ impl<'a> BitOr<&'a Helpers> for Helpers {
 }
 
 pub struct InjectHelpers {
-    pub cm: Rc<SourceMap>,
+    pub cm: Lrc<SourceMap>,
     pub helpers: Arc<Helpers>,
 }
 
diff --git a/ecmascript/transforms/src/tests.rs b/ecmascript/transforms/src/tests.rs
index eb81027b766..cf13a0f8b5b 100644
--- a/ecmascript/transforms/src/tests.rs
+++ b/ecmascript/transforms/src/tests.rs
@@ -1,12 +1,11 @@
+use ast::*;
 use slog::Logger;
 use sourcemap::SourceMapBuilder;
 use std::{
     io::{self, Write},
-    rc::Rc,
     sync::{Arc, RwLock},
 };
-use swc_common::{errors::Handler, FileName, Fold, FoldWith, SourceMap};
-use ast::*;
+use swc_common::{errors::Handler, sync::Lrc, FileName, Fold, FoldWith, SourceMap};
 use swc_ecma_codegen::Emitter;
 use swc_ecma_parser::{Parser, Session, SourceFileInput};
 
@@ -15,7 +14,7 @@ struct MyHandlers;
 impl swc_ecma_codegen::Handlers for MyHandlers {}
 
 pub(crate) struct Tester<'a> {
-    cm: Rc<SourceMap>,
+    cm: Lrc<SourceMap>,
     logger: Logger,
     handler: &'a Handler,
 }
diff --git a/libswc/src/lib.rs b/libswc/src/lib.rs
index 4e84c8f0775..69b6e9b1195 100644
--- a/libswc/src/lib.rs
+++ b/libswc/src/lib.rs
@@ -9,7 +9,7 @@ pub extern crate swc_common as common;
 pub extern crate swc_ecmascript as ecmascript;
 
 use self::{
-    common::{errors::Handler, SourceMap},
+    common::{errors::Handler, sync::Lrc, SourceMap},
     ecmascript::{
         ast::Module,
         codegen::{self, Emitter},
@@ -21,17 +21,16 @@ use sourcemap::SourceMapBuilder;
 use std::{
     io::{self, Write},
     path::Path,
-    rc::Rc,
 };
 
 pub struct Compiler {
-    cm: Rc<SourceMap>,
+    cm: Lrc<SourceMap>,
     logger: Logger,
     handler: Handler,
 }
 
 impl Compiler {
-    pub fn new(logger: Logger, cm: Rc<SourceMap>, handler: Handler) -> Self {
+    pub fn new(logger: Logger, cm: Lrc<SourceMap>, handler: Handler) -> Self {
         Compiler {
             cm,
             logger,
diff --git a/src/bin/swc.rs b/src/bin/swc.rs
index a21e1073255..14f7e56fa6a 100644
--- a/src/bin/swc.rs
+++ b/src/bin/swc.rs
@@ -14,11 +14,10 @@ use std::{
     error::Error,
     io::{self, Write},
     path::Path,
-    rc::Rc,
     sync::Arc,
 };
 use swc::{
-    common::{errors::Handler, FilePathMapping, Fold, SourceMap},
+    common::{errors::Handler, sync::Lrc, FilePathMapping, Fold, SourceMap},
     ecmascript::{ast::Module, codegen},
     Compiler,
 };
@@ -70,7 +69,7 @@ fn run() -> Result<(), Box<Error>> {
         .build_global()
         .expect("failed to configure rayon::ThreadPool");
 
-    let cm = Rc::new(SourceMap::new(FilePathMapping::empty()));
+    let cm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
 
     let handler = Handler::with_tty_emitter(
         swc::common::errors::ColorConfig::Always,
@@ -110,7 +109,7 @@ fn run() -> Result<(), Box<Error>> {
     Ok(())
 }
 
-fn js_pass(cm: Rc<SourceMap>, matches: &ArgMatches) -> Box<Fold<Module>> {
+fn js_pass(cm: Lrc<SourceMap>, matches: &ArgMatches) -> Box<Fold<Module>> {
     use swc::ecmascript::transforms::{compat, simplifier};
     let helpers = Arc::new(compat::helpers::Helpers::default());
 
diff --git a/testing/src/errors.rs b/testing/src/errors.rs
index 2cf78158b7c..423e71e7f6e 100644
--- a/testing/src/errors.rs
+++ b/testing/src/errors.rs
@@ -1,13 +1,15 @@
 use super::StdErr;
 use std::{
     io::{self, Write},
-    rc::Rc,
     sync::{Arc, RwLock},
 };
-use swc_common::errors::{EmitterWriter, Handler, HandlerFlags, SourceMapperDyn};
+use swc_common::{
+    errors::{EmitterWriter, Handler, HandlerFlags, SourceMapperDyn},
+    sync::Lrc,
+};
 
 /// Creates a new handler for testing.
-pub(crate) fn new_handler(cm: Rc<SourceMapperDyn>) -> (Handler, BufferedError) {
+pub(crate) fn new_handler(cm: Lrc<SourceMapperDyn>) -> (Handler, BufferedError) {
     let buf: BufferedError = Default::default();
 
     let e = EmitterWriter::new(box buf.clone(), Some(cm.clone()), false, true);
diff --git a/testing/src/lib.rs b/testing/src/lib.rs
index 83d4ba7c6d7..da3894fec5b 100644
--- a/testing/src/lib.rs
+++ b/testing/src/lib.rs
@@ -22,10 +22,9 @@ use std::{
     fs::{create_dir_all, File},
     io::{self, Write},
     path::Path,
-    rc::Rc,
     thread,
 };
-use swc_common::{errors::Handler, FilePathMapping, Fold, FoldWith, SourceMap, Span};
+use swc_common::{errors::Handler, sync::Lrc, FilePathMapping, Fold, FoldWith, SourceMap, Span};
 
 #[macro_use]
 mod macros;
@@ -35,9 +34,9 @@ mod paths;
 
 pub fn run_test<F, Ret>(op: F) -> Result<Ret, StdErr>
 where
-    F: FnOnce(Logger, Rc<SourceMap>, &Handler) -> Result<Ret, ()>,
+    F: FnOnce(Logger, Lrc<SourceMap>, &Handler) -> Result<Ret, ()>,
 {
-    let cm = Rc::new(SourceMap::new(FilePathMapping::empty()));
+    let cm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
     let (handler, errors) = self::errors::new_handler(cm.clone());
     let result =
         swc_common::GLOBALS.set(&swc_common::Globals::new(), || op(logger(), cm, &handler));