feat(ops): Fast zero copy string arguments (#16777)

Uses SeqOneByteString optimization to do zero-copy `&str` arguments in
fast calls.

- [x] Depends on https://github.com/denoland/rusty_v8/pull/1129
- [x] Depends on
https://chromium-review.googlesource.com/c/v8/v8/+/4036884
- [x] Disable in async ops
- [x] Make it work with owned `String` with an extra alloc in fast path.
- [x] Support `Cow<'_, str>`. Owned for slow case, Borrowed for fast
case

```rust
#[op]
fn op_string_len(s: &str) -> u32 { 
  str.len() as u32 
}
```

34 files changed, 805 insertions, 98 deletions

diff --git a/cli/bench/console.js b/cli/bench/console.js
index b1873953c..1e0ebb37a 100644
--- a/cli/bench/console.js
+++ b/cli/bench/console.js
@@ -1,8 +1,3 @@
 // Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
 const count = 100000;
-
-const start = Date.now();
 for (let i = 0; i < count; i++) console.log("Hello World");
-const elapsed = Date.now() - start;
-const rate = Math.floor(count / (elapsed / 1000));
-console.log(`time ${elapsed} ms rate ${rate}`);
diff --git a/cli/bench/encode_into.js b/cli/bench/encode_into.js
index aaee23434..458a88b84 100644
--- a/cli/bench/encode_into.js
+++ b/cli/bench/encode_into.js
@@ -1,11 +1,10 @@
 // Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
-const queueMicrotask = globalThis.queueMicrotask || process.nextTick;
 let [total, count] = typeof Deno !== "undefined"
   ? Deno.args
   : [process.argv[2], process.argv[3]];
 
 total = total ? parseInt(total, 0) : 50;
-count = count ? parseInt(count, 10) : 1000000;
+count = count ? parseInt(count, 10) : 10000000;
 
 function bench(fun) {
   const start = Date.now();
@@ -13,7 +12,7 @@ function bench(fun) {
   const elapsed = Date.now() - start;
   const rate = Math.floor(count / (elapsed / 1000));
   console.log(`time ${elapsed} ms rate ${rate}`);
-  if (--total) queueMicrotask(() => bench(fun));
+  if (--total) bench(fun);
 }
 
 const encoder = new TextEncoder();
diff --git a/cli/bench/webstorage.js b/cli/bench/webstorage.js
new file mode 100644
index 000000000..bdb10e568
--- /dev/null
+++ b/cli/bench/webstorage.js
@@ -0,0 +1,21 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+
+// Note: when benchmarking across different Deno version, make sure to clear
+// the DENO_DIR cache.
+let [total, count] = typeof Deno !== "undefined" ? Deno.args : [];
+
+total = total ? parseInt(total, 0) : 50;
+count = count ? parseInt(count, 10) : 1000000;
+
+function bench(fun) {
+  const start = Date.now();
+  for (let i = 0; i < count; i++) fun(i);
+  const elapsed = Date.now() - start;
+  const rate = Math.floor(count / (elapsed / 1000));
+  console.log(`time ${elapsed} ms rate ${rate}`);
+  if (--total) queueMicrotask(() => bench(fun));
+}
+
+localStorage.clear();
+localStorage.setItem("foo", "bar");
+bench(() => localStorage.getItem("foo"));
diff --git a/cli/tsc/mod.rs b/cli/tsc/mod.rs
index a8eb15c19..1fb4d32d3 100644
--- a/cli/tsc/mod.rs
+++ b/cli/tsc/mod.rs
@@ -683,9 +683,9 @@ pub fn resolve_npm_package_reference_types(
 }
 
 #[op]
-fn op_is_node_file(state: &mut OpState, path: String) -> bool {
+fn op_is_node_file(state: &mut OpState, path: &str) -> bool {
   let state = state.borrow::<State>();
-  match ModuleSpecifier::parse(&path) {
+  match ModuleSpecifier::parse(path) {
     Ok(specifier) => state
       .maybe_npm_resolver
       .as_ref()
diff --git a/core/ops_builtin.rs b/core/ops_builtin.rs
index 6374e9951..858ce97bd 100644
--- a/core/ops_builtin.rs
+++ b/core/ops_builtin.rs
@@ -107,7 +107,7 @@ pub fn op_metrics(state: &mut OpState) -> (OpMetrics, Vec<OpMetrics>) {
 
 /// Builtin utility to print to stdout/stderr
 #[op]
-pub fn op_print(msg: String, is_err: bool) -> Result<(), Error> {
+pub fn op_print(msg: &str, is_err: bool) -> Result<(), Error> {
   if is_err {
     stderr().write_all(msg.as_bytes())?;
     stderr().flush().unwrap();
@@ -152,12 +152,12 @@ pub fn op_wasm_streaming_feed(
 pub fn op_wasm_streaming_set_url(
   state: &mut OpState,
   rid: ResourceId,
-  url: String,
+  url: &str,
 ) -> Result<(), Error> {
   let wasm_streaming =
     state.resource_table.get::<WasmStreamingResource>(rid)?;
 
-  wasm_streaming.0.borrow_mut().set_url(&url);
+  wasm_streaming.0.borrow_mut().set_url(url);
 
   Ok(())
 }
diff --git a/ext/node/lib.rs b/ext/node/lib.rs
index b2443db0b..5282c0660 100644
--- a/ext/node/lib.rs
+++ b/ext/node/lib.rs
@@ -262,7 +262,7 @@ fn op_require_proxy_path(filename: String) -> String {
 }
 
 #[op]
-fn op_require_is_request_relative(request: String) -> bool {
+fn op_require_is_request_relative(request: &str) -> bool {
   if request.starts_with("./") || request.starts_with("../") || request == ".."
   {
     return true;
diff --git a/ext/url/00_url.js b/ext/url/00_url.js
index 5479cb59c..754c647b1 100644
--- a/ext/url/00_url.js
+++ b/ext/url/00_url.js
@@ -56,12 +56,12 @@
   function opUrlParse(href, maybeBase) {
     let status;
     if (maybeBase === undefined) {
-      status = ops.op_url_parse(href, componentsBuf.buffer);
+      status = ops.op_url_parse(href, componentsBuf);
     } else {
-      status = core.ops.op_url_parse_with_base(
+      status = ops.op_url_parse_with_base(
         href,
         maybeBase,
-        componentsBuf.buffer,
+        componentsBuf,
       );
     }
     return getSerialization(status, href);
@@ -71,7 +71,7 @@
     if (status === 0) {
       return href;
     } else if (status === 1) {
-      return core.ops.op_url_get_serialization();
+      return ops.op_url_get_serialization();
     } else {
       throw new TypeError("Invalid URL");
     }
diff --git a/ext/url/lib.rs b/ext/url/lib.rs
index ac668207f..01014ccd3 100644
--- a/ext/url/lib.rs
+++ b/ext/url/lib.rs
@@ -41,11 +41,11 @@ pub fn init() -> Extension {
 #[op]
 pub fn op_url_parse_with_base(
   state: &mut OpState,
-  href: String,
-  base_href: String,
-  buf: &mut [u8],
+  href: &str,
+  base_href: &str,
+  buf: &mut [u32],
 ) -> u32 {
-  let base_url = match Url::parse(&base_href) {
+  let base_url = match Url::parse(base_href) {
     Ok(url) => url,
     Err(_) => return ParseStatus::Err as u32,
   };
@@ -67,8 +67,8 @@ pub fn op_url_get_serialization(state: &mut OpState) -> String {
 }
 
 /// Parse `href` without a `base_url`. Fills the out `buf` with URL components.
-#[op]
-pub fn op_url_parse(state: &mut OpState, href: String, buf: &mut [u8]) -> u32 {
+#[op(fast)]
+pub fn op_url_parse(state: &mut OpState, href: &str, buf: &mut [u32]) -> u32 {
   parse_url(state, href, None, buf)
 }
 
@@ -99,15 +99,14 @@ pub fn op_url_parse(state: &mut OpState, href: String, buf: &mut [u8]) -> u32 {
 #[inline]
 fn parse_url(
   state: &mut OpState,
-  href: String,
+  href: &str,
   base_href: Option<&Url>,
-  buf: &mut [u8],
+  buf: &mut [u32],
 ) -> u32 {
-  match Url::options().base_url(base_href).parse(&href) {
+  match Url::options().base_url(base_href).parse(href) {
     Ok(url) => {
       let inner_url = quirks::internal_components(&url);
 
-      let buf: &mut [u32] = as_u32_slice(buf);
       buf[0] = inner_url.scheme_end;
       buf[1] = inner_url.username_end;
       buf[2] = inner_url.host_start;
diff --git a/ext/web/blob.rs b/ext/web/blob.rs
index 7da42e178..5f1936860 100644
--- a/ext/web/blob.rs
+++ b/ext/web/blob.rs
@@ -252,9 +252,9 @@ pub fn op_blob_create_object_url(
 #[op]
 pub fn op_blob_revoke_object_url(
   state: &mut deno_core::OpState,
-  url: String,
+  url: &str,
 ) -> Result<(), AnyError> {
-  let url = Url::parse(&url)?;
+  let url = Url::parse(url)?;
   let blob_store = state.borrow::<BlobStore>();
   blob_store.remove_object_url(&url);
   Ok(())
diff --git a/ext/web/compression.rs b/ext/web/compression.rs
index d2647e498..05dcf02b1 100644
--- a/ext/web/compression.rs
+++ b/ext/web/compression.rs
@@ -41,11 +41,11 @@ impl Resource for CompressionResource {
 #[op]
 pub fn op_compression_new(
   state: &mut OpState,
-  format: String,
+  format: &str,
   is_decoder: bool,
 ) -> ResourceId {
   let w = Vec::new();
-  let inner = match (format.as_str(), is_decoder) {
+  let inner = match (format, is_decoder) {
     ("deflate", true) => Inner::DeflateDecoder(ZlibDecoder::new(w)),
     ("deflate", false) => {
       Inner::DeflateEncoder(ZlibEncoder::new(w, Compression::default()))
diff --git a/ext/web/lib.rs b/ext/web/lib.rs
index cfbcee6e3..7c75a9a28 100644
--- a/ext/web/lib.rs
+++ b/ext/web/lib.rs
@@ -270,7 +270,7 @@ fn op_encoding_decode_single(
 #[op]
 fn op_encoding_new_decoder(
   state: &mut OpState,
-  label: String,
+  label: &str,
   fatal: bool,
   ignore_bom: bool,
 ) -> Result<ResourceId, AnyError> {
@@ -352,25 +352,43 @@ impl Resource for TextDecoderResource {
   }
 }
 
-#[op(v8)]
+#[op]
 fn op_encoding_encode_into(
-  scope: &mut v8::HandleScope,
-  input: serde_v8::Value,
+  input: Cow<'_, str>,
   buffer: &mut [u8],
   out_buf: &mut [u32],
-) -> Result<(), AnyError> {
-  let s = v8::Local::<v8::String>::try_from(input.v8_value)?;
-
-  let mut nchars = 0;
-  out_buf[1] = s.write_utf8(
-    scope,
-    buffer,
-    Some(&mut nchars),
-    v8::WriteOptions::NO_NULL_TERMINATION
-      | v8::WriteOptions::REPLACE_INVALID_UTF8,
-  ) as u32;
-  out_buf[0] = nchars as u32;
-  Ok(())
+) {
+  // Since `input` is already UTF-8, we can simply find the last UTF-8 code
+  // point boundary from input that fits in `buffer`, and copy the bytes up to
+  // that point.
+  let boundary = if buffer.len() >= input.len() {
+    input.len()
+  } else {
+    let mut boundary = buffer.len();
+
+    // The maximum length of a UTF-8 code point is 4 bytes.
+    for _ in 0..4 {
+      if input.is_char_boundary(boundary) {
+        break;
+      }
+      debug_assert!(boundary > 0);
+      boundary -= 1;
+    }
+
+    debug_assert!(input.is_char_boundary(boundary));
+    boundary
+  };
+
+  buffer[..boundary].copy_from_slice(input[..boundary].as_bytes());
+
+  // The `read` output parameter is measured in UTF-16 code units.
+  out_buf[0] = match input {
+    // Borrowed Cow strings are zero-copy views into the V8 heap.
+    // Thus, they are guarantee to be SeqOneByteString.
+    Cow::Borrowed(v) => v[..boundary].len() as u32,
+    Cow::Owned(v) => v[..boundary].encode_utf16().count() as u32,
+  };
+  out_buf[1] = boundary as u32;
 }
 
 #[op(v8)]
diff --git a/ext/webstorage/lib.rs b/ext/webstorage/lib.rs
index 6284a59bc..58b7c07e4 100644
--- a/ext/webstorage/lib.rs
+++ b/ext/webstorage/lib.rs
@@ -139,8 +139,8 @@ pub fn op_webstorage_key(
 #[op]
 pub fn op_webstorage_set(
   state: &mut OpState,
-  key: String,
-  value: String,
+  key: &str,
+  value: &str,
   persistent: bool,
 ) -> Result<(), AnyError> {
   let conn = get_webstorage(state, persistent)?;
@@ -184,7 +184,7 @@ pub fn op_webstorage_get(
 #[op]
 pub fn op_webstorage_remove(
   state: &mut OpState,
-  key_name: String,
+  key_name: &str,
   persistent: bool,
 ) -> Result<(), AnyError> {
   let conn = get_webstorage(state, persistent)?;
diff --git a/ops/fast_call.rs b/ops/fast_call.rs
index f2ed8cb2d..1d6bfa1fa 100644
--- a/ops/fast_call.rs
+++ b/ops/fast_call.rs
@@ -403,7 +403,9 @@ fn q_fast_ty(v: &FastValue) -> Quote {
     FastValue::F64 => q!({ f64 }),
     FastValue::Bool => q!({ bool }),
     FastValue::V8Value => q!({ v8::Local<v8::Value> }),
-    FastValue::Uint8Array | FastValue::Uint32Array => unreachable!(),
+    FastValue::Uint8Array
+    | FastValue::Uint32Array
+    | FastValue::SeqOneByteString => unreachable!(),
   }
 }
 
@@ -421,6 +423,7 @@ fn q_fast_ty_variant(v: &FastValue) -> Quote {
     FastValue::V8Value => q!({ V8Value }),
     FastValue::Uint8Array => q!({ TypedArray(CType::Uint8) }),
     FastValue::Uint32Array => q!({ TypedArray(CType::Uint32) }),
+    FastValue::SeqOneByteString => q!({ SeqOneByteString }),
   }
 }
 
diff --git a/ops/lib.rs b/ops/lib.rs
index 598350167..26fcb2a78 100644
--- a/ops/lib.rs
+++ b/ops/lib.rs
@@ -400,7 +400,12 @@ fn codegen_arg(
     return quote! { let #ident = (); };
   }
   // Fast path for `String`
-  if is_string(&**ty) {
+  if let Some(is_ref) = is_string(&**ty) {
+    let ref_block = if is_ref {
+      quote! { let #ident = #ident.as_ref(); }
+    } else {
+      quote! {}
+    };
     return quote! {
       let #ident = match #core::v8::Local::<#core::v8::String>::try_from(args.get(#idx as i32)) {
         Ok(v8_string) => #core::serde_v8::to_utf8(v8_string, scope),
@@ -408,6 +413,18 @@ fn codegen_arg(
           return #core::_ops::throw_type_error(scope, format!("Expected string at position {}", #idx));
         }
       };
+      #ref_block
+    };
+  }
+  // Fast path for `Cow<'_, str>`
+  if is_cow_str(&**ty) {
+    return quote! {
+      let #ident = match #core::v8::Local::<#core::v8::String>::try_from(args.get(#idx as i32)) {
+        Ok(v8_string) => ::std::borrow::Cow::Owned(#core::serde_v8::to_utf8(v8_string, scope)),
+        Err(_) => {
+          return #core::_ops::throw_type_error(scope, format!("Expected string at position {}", #idx));
+        }
+      };
     };
   }
   // Fast path for `Option<String>`
@@ -618,14 +635,25 @@ fn is_result(ty: impl ToTokens) -> bool {
   }
 }
 
-fn is_string(ty: impl ToTokens) -> bool {
-  tokens(ty) == "String"
+fn is_string(ty: impl ToTokens) -> Option<bool> {
+  let toks = tokens(ty);
+  if toks == "String" {
+    return Some(false);
+  }
+  if toks == "& str" {
+    return Some(true);
+  }
+  None
 }
 
 fn is_option_string(ty: impl ToTokens) -> bool {
   tokens(ty) == "Option < String >"
 }
 
+fn is_cow_str(ty: impl ToTokens) -> bool {
+  tokens(&ty).starts_with("Cow <") && tokens(&ty).ends_with("str >")
+}
+
 enum SliceType {
   U8,
   U8Mut,
diff --git a/ops/optimizer.rs b/ops/optimizer.rs
index d25857032..17435407c 100644
--- a/ops/optimizer.rs
+++ b/ops/optimizer.rs
@@ -20,11 +20,19 @@ pub(crate) enum BailoutReason {
 }
 
 #[derive(Debug, PartialEq)]
+enum StringType {
+  Cow,
+  Ref,
+  Owned,
+}
+
+#[derive(Debug, PartialEq)]
 enum TransformKind {
   // serde_v8::Value
   V8Value,
   SliceU32(bool),
   SliceU8(bool),
+  SeqOneByteString(StringType),
   PtrU8,
   WasmMemory,
 }
@@ -51,6 +59,13 @@ impl Transform {
     }
   }
 
+  fn seq_one_byte_string(index: usize, is_ref: StringType) -> Self {
+    Transform {
+      kind: TransformKind::SeqOneByteString(is_ref),
+      index,
+    }
+  }
+
   fn wasm_memory(index: usize) -> Self {
     Transform {
       kind: TransformKind::WasmMemory,
@@ -132,6 +147,21 @@ impl Transform {
           };
         })
       }
+      // &str
+      TransformKind::SeqOneByteString(str_ty) => {
+        *ty = parse_quote! { *const #core::v8::fast_api::FastApiOneByteString };
+        match str_ty {
+          StringType::Ref => q!(Vars { var: &ident }, {
+            let var = unsafe { &*var }.as_str();
+          }),
+          StringType::Cow => q!(Vars { var: &ident }, {
+            let var = ::std::borrow::Cow::Borrowed(unsafe { &*var }.as_str());
+          }),
+          StringType::Owned => q!(Vars { var: &ident }, {
+            let var = unsafe { &*var }.as_str().to_owned();
+          }),
+        }
+      }
       TransformKind::WasmMemory => {
         // Note: `ty` is correctly set to __opts by the fast call tier.
         q!(Vars { var: &ident, core }, {
@@ -198,6 +228,7 @@ pub(crate) enum FastValue {
   V8Value,
   Uint8Array,
   Uint32Array,
+  SeqOneByteString,
 }
 
 impl Default for FastValue {
@@ -550,10 +581,58 @@ impl Optimizer {
                 }
               }
             }
+            // Cow<'_, str>
+            PathSegment {
+              ident, arguments, ..
+            } if ident == "Cow" => {
+              if let PathArguments::AngleBracketed(
+                AngleBracketedGenericArguments { args, .. },
+              ) = arguments
+              {
+                assert_eq!(args.len(), 2);
+
+                let ty = &args[1];
+                match ty {
+                  GenericArgument::Type(Type::Path(TypePath {
+                    path: Path { segments, .. },
+                    ..
+                  })) => {
+                    let segment = single_segment(segments)?;
+                    match segment {
+                      PathSegment { ident, .. } if ident == "str" => {
+                        self.fast_parameters.push(FastValue::SeqOneByteString);
+                        assert!(self
+                          .transforms
+                          .insert(
+                            index,
+                            Transform::seq_one_byte_string(
+                              index,
+                              StringType::Cow
+                            )
+                          )
+                          .is_none());
+                      }
+                      _ => return Err(BailoutReason::FastUnsupportedParamType),
+                    }
+                  }
+                  _ => return Err(BailoutReason::FastUnsupportedParamType),
+                }
+              }
+            }
             // Is `T` a fast scalar?
             PathSegment { ident, .. } => {
               if let Some(val) = get_fast_scalar(ident.to_string().as_str()) {
                 self.fast_parameters.push(val);
+              } else if ident == "String" {
+                // Is `T` an owned String?
+                self.fast_parameters.push(FastValue::SeqOneByteString);
+                assert!(self
+                  .transforms
+                  .insert(
+                    index,
+                    Transform::seq_one_byte_string(index, StringType::Owned)
+                  )
+                  .is_none());
               } else {
                 return Err(BailoutReason::FastUnsupportedParamType);
               }
@@ -574,6 +653,17 @@ impl Optimizer {
               PathSegment { ident, .. } if ident == "OpState" => {
                 self.has_ref_opstate = true;
               }
+              // Is `T` a str?
+              PathSegment { ident, .. } if ident == "str" => {
+                self.fast_parameters.push(FastValue::SeqOneByteString);
+                assert!(self
+                  .transforms
+                  .insert(
+                    index,
+                    Transform::seq_one_byte_string(index, StringType::Ref)
+                  )
+                  .is_none());
+              }
               _ => return Err(BailoutReason::FastUnsupportedParamType),
             }
           }
diff --git a/ops/optimizer_tests/cow_str.expected b/ops/optimizer_tests/cow_str.expected
new file mode 100644
index 000000000..8b28965ba
--- /dev/null
+++ b/ops/optimizer_tests/cow_str.expected
@@ -0,0 +1,11 @@
+=== Optimizer Dump ===
+returns_result: false
+has_ref_opstate: false
+has_rc_opstate: false
+has_fast_callback_option: false
+needs_fast_callback_option: false
+fast_result: Some(Void)
+fast_parameters: [V8Value, SeqOneByteString]
+transforms: {0: Transform { kind: SeqOneByteString(Cow), index: 0 }}
+is_async: false
+fast_compatible: true
diff --git a/ops/optimizer_tests/cow_str.out b/ops/optimizer_tests/cow_str.out
new file mode 100644
index 000000000..da405f451
--- /dev/null
+++ b/ops/optimizer_tests/cow_str.out
@@ -0,0 +1,87 @@
+#[allow(non_camel_case_types)]
+///Auto-generated by `deno_ops`, i.e: `#[op]`
+///
+///Use `op_cow_str::decl()` to get an op-declaration
+///you can include in a `deno_core::Extension`.
+pub struct op_cow_str;
+#[doc(hidden)]
+impl op_cow_str {
+    pub fn name() -> &'static str {
+        stringify!(op_cow_str)
+    }
+    pub fn v8_fn_ptr<'scope>() -> deno_core::v8::FunctionCallback {
+        use deno_core::v8::MapFnTo;
+        Self::v8_func.map_fn_to()
+    }
+    pub fn decl<'scope>() -> deno_core::OpDecl {
+        deno_core::OpDecl {
+            name: Self::name(),
+            v8_fn_ptr: Self::v8_fn_ptr(),
+            enabled: true,
+            fast_fn: Some(
+                Box::new(op_cow_str_fast {
+                    _phantom: ::std::marker::PhantomData,
+                }),
+            ),
+            is_async: false,
+            is_unstable: false,
+            is_v8: false,
+            argc: 1usize,
+        }
+    }
+    #[inline]
+    #[allow(clippy::too_many_arguments)]
+    fn call(c: Cow<'_, str>) {}
+    pub fn v8_func<'scope>(
+        scope: &mut deno_core::v8::HandleScope<'scope>,
+        args: deno_core::v8::FunctionCallbackArguments,
+        mut rv: deno_core::v8::ReturnValue,
+    ) {
+        let ctx = unsafe {
+            &*(deno_core::v8::Local::<deno_core::v8::External>::cast(args.data()).value()
+                as *const deno_core::_ops::OpCtx)
+        };
+        let arg_0 = match deno_core::v8::Local::<
+            deno_core::v8::String,
+        >::try_from(args.get(0usize as i32)) {
+            Ok(v8_string) => {
+                ::std::borrow::Cow::Owned(deno_core::serde_v8::to_utf8(v8_string, scope))
+            }
+            Err(_) => {
+                return deno_core::_ops::throw_type_error(
+                    scope,
+                    format!("Expected string at position {}", 0usize),
+                );
+            }
+        };
+        let result = Self::call(arg_0);
+        let op_state = ::std::cell::RefCell::borrow(&*ctx.state);
+        op_state.tracker.track_sync(ctx.id);
+    }
+}
+struct op_cow_str_fast {
+    _phantom: ::std::marker::PhantomData<()>,
+}
+impl<'scope> deno_core::v8::fast_api::FastFunction for op_cow_str_fast {
+    fn function(&self) -> *const ::std::ffi::c_void {
+        op_cow_str_fast_fn as *const ::std::ffi::c_void
+    }
+    fn args(&self) -> &'static [deno_core::v8::fast_api::Type] {
+        use deno_core::v8::fast_api::Type::*;
+        use deno_core::v8::fast_api::CType;
+        &[V8Value, SeqOneByteString]
+    }
+    fn return_type(&self) -> deno_core::v8::fast_api::CType {
+        deno_core::v8::fast_api::CType::Void
+    }
+}
+fn op_cow_str_fast_fn<'scope>(
+    _: deno_core::v8::Local<deno_core::v8::Object>,
+    c: *const deno_core::v8::fast_api::FastApiOneByteString,
+) -> () {
+    use deno_core::v8;
+    use deno_core::_ops;
+    let c = ::std::borrow::Cow::Borrowed(unsafe { &*c }.as_str());
+    let result = op_cow_str::call(c);
+    result
+}
diff --git a/ops/optimizer_tests/cow_str.rs b/ops/optimizer_tests/cow_str.rs
new file mode 100644
index 000000000..b7214bdc7
--- /dev/null
+++ b/ops/optimizer_tests/cow_str.rs
@@ -0,0 +1,3 @@
+fn op_cow_str(c: Cow<'_, str>) {
+  // ...
+}
diff --git a/ops/optimizer_tests/op_blob_revoke_object_url.expected b/ops/optimizer_tests/op_blob_revoke_object_url.expected
index 0fae25e86..5b3e43edc 100644
--- a/ops/optimizer_tests/op_blob_revoke_object_url.expected
+++ b/ops/optimizer_tests/op_blob_revoke_object_url.expected
@@ -1 +1,11 @@
-MustBeSingleSegment
\ No newline at end of file
+=== Optimizer Dump ===
+returns_result: true
+has_ref_opstate: true
+has_rc_opstate: false
+has_fast_callback_option: false
+needs_fast_callback_option: false
+fast_result: Some(Void)
+fast_parameters: [V8Value, SeqOneByteString]
+transforms: {1: Transform { kind: SeqOneByteString(Owned), index: 1 }}
+is_async: false
+fast_compatible: true
diff --git a/ops/optimizer_tests/op_blob_revoke_object_url.out b/ops/optimizer_tests/op_blob_revoke_object_url.out
index 72bc75e05..28fe17acb 100644
--- a/ops/optimizer_tests/op_blob_revoke_object_url.out
+++ b/ops/optimizer_tests/op_blob_revoke_object_url.out
@@ -18,7 +18,11 @@ impl op_blob_revoke_object_url {
             name: Self::name(),
             v8_fn_ptr: Self::v8_fn_ptr(),
             enabled: true,
-            fast_fn: None,
+            fast_fn: Some(
+                Box::new(op_blob_revoke_object_url_fast {
+                    _phantom: ::std::marker::PhantomData,
+                }),
+            ),
             is_async: false,
             is_unstable: false,
             is_v8: false,
@@ -27,7 +31,7 @@ impl op_blob_revoke_object_url {
     }
     #[inline]
     #[allow(clippy::too_many_arguments)]
-    pub fn call(state: &mut deno_core::OpState, url: String) -> Result<(), AnyError> {
+    pub fn call(state: &mut OpState, url: String) -> Result<(), AnyError> {
         let url = Url::parse(&url)?;
         let blob_store = state.borrow::<BlobStore>();
         blob_store.remove_object_url(&url);
@@ -42,6 +46,18 @@ impl op_blob_revoke_object_url {
             &*(deno_core::v8::Local::<deno_core::v8::External>::cast(args.data()).value()
                 as *const deno_core::_ops::OpCtx)
         };
+        {
+            let op_state = &mut std::cell::RefCell::borrow_mut(&ctx.state);
+            if let Some(err) = op_state.last_fast_op_error.take() {
+                let exception = deno_core::error::to_v8_error(
+                    scope,
+                    op_state.get_error_class_fn,
+                    &err,
+                );
+                scope.throw_exception(exception);
+                return;
+            }
+        }
         let arg_0 = match deno_core::v8::Local::<
             deno_core::v8::String,
         >::try_from(args.get(0usize as i32)) {
@@ -69,3 +85,45 @@ impl op_blob_revoke_object_url {
         };
     }
 }
+struct op_blob_revoke_object_url_fast {
+    _phantom: ::std::marker::PhantomData<()>,
+}
+impl<'scope> deno_core::v8::fast_api::FastFunction for op_blob_revoke_object_url_fast {
+    fn function(&self) -> *const ::std::ffi::c_void {
+        op_blob_revoke_object_url_fast_fn as *const ::std::ffi::c_void
+    }
+    fn args(&self) -> &'static [deno_core::v8::fast_api::Type] {
+        use deno_core::v8::fast_api::Type::*;
+        use deno_core::v8::fast_api::CType;
+        &[V8Value, SeqOneByteString, CallbackOptions]
+    }
+    fn return_type(&self) -> deno_core::v8::fast_api::CType {
+        deno_core::v8::fast_api::CType::Void
+    }
+}
+fn op_blob_revoke_object_url_fast_fn<'scope>(
+    _: deno_core::v8::Local<deno_core::v8::Object>,
+    url: *const deno_core::v8::fast_api::FastApiOneByteString,
+    fast_api_callback_options: *mut deno_core::v8::fast_api::FastApiCallbackOptions,
+) -> () {
+    use deno_core::v8;
+    use deno_core::_ops;
+    let __opts: &mut v8::fast_api::FastApiCallbackOptions = unsafe {
+        &mut *fast_api_callback_options
+    };
+    let __ctx = unsafe {
+        &*(v8::Local::<v8::External>::cast(unsafe { __opts.data.data }).value()
+            as *const _ops::OpCtx)
+    };
+    let state = &mut ::std::cell::RefCell::borrow_mut(&__ctx.state);
+    let url = unsafe { &*url }.as_str().to_owned();
+    let result = op_blob_revoke_object_url::call(state, url);
+    match result {
+        Ok(result) => result,
+        Err(err) => {
+            state.last_fast_op_error.replace(err);
+            __opts.fallback = true;
+            Default::default()
+        }
+    }
+}
diff --git a/ops/optimizer_tests/op_blob_revoke_object_url.rs b/ops/optimizer_tests/op_blob_revoke_object_url.rs
index 8e139da06..b51a2ed7f 100644
--- a/ops/optimizer_tests/op_blob_revoke_object_url.rs
+++ b/ops/optimizer_tests/op_blob_revoke_object_url.rs
@@ -1,5 +1,5 @@
 pub fn op_blob_revoke_object_url(
-  state: &mut deno_core::OpState,
+  state: &mut OpState,
   url: String,
 ) -> Result<(), AnyError> {
   let url = Url::parse(&url)?;
diff --git a/ops/optimizer_tests/op_print.expected b/ops/optimizer_tests/op_print.expected
new file mode 100644
index 000000000..fb52693aa
--- /dev/null
+++ b/ops/optimizer_tests/op_print.expected
@@ -0,0 +1,11 @@
+=== Optimizer Dump ===
+returns_result: true
+has_ref_opstate: true
+has_rc_opstate: false
+has_fast_callback_option: false
+needs_fast_callback_option: false
+fast_result: Some(Void)
+fast_parameters: [V8Value, SeqOneByteString, Bool]
+transforms: {1: Transform { kind: SeqOneByteString(Ref), index: 1 }}
+is_async: false
+fast_compatible: true
diff --git a/ops/optimizer_tests/op_print.out b/ops/optimizer_tests/op_print.out
new file mode 100644
index 000000000..5d0062a01
--- /dev/null
+++ b/ops/optimizer_tests/op_print.out
@@ -0,0 +1,141 @@
+#[allow(non_camel_case_types)]
+///Auto-generated by `deno_ops`, i.e: `#[op]`
+///
+///Use `op_print::decl()` to get an op-declaration
+///you can include in a `deno_core::Extension`.
+pub struct op_print;
+#[doc(hidden)]
+impl op_print {
+    pub fn name() -> &'static str {
+        stringify!(op_print)
+    }
+    pub fn v8_fn_ptr<'scope>() -> deno_core::v8::FunctionCallback {
+        use deno_core::v8::MapFnTo;
+        Self::v8_func.map_fn_to()
+    }
+    pub fn decl<'scope>() -> deno_core::OpDecl {
+        deno_core::OpDecl {
+            name: Self::name(),
+            v8_fn_ptr: Self::v8_fn_ptr(),
+            enabled: true,
+            fast_fn: Some(
+                Box::new(op_print_fast {
+                    _phantom: ::std::marker::PhantomData,
+                }),
+            ),
+            is_async: false,
+            is_unstable: false,
+            is_v8: false,
+            argc: 2usize,
+        }
+    }
+    #[inline]
+    #[allow(clippy::too_many_arguments)]
+    fn call(state: &mut OpState, msg: &str, is_err: bool) -> Result<(), AnyError> {}
+    pub fn v8_func<'scope>(
+        scope: &mut deno_core::v8::HandleScope<'scope>,
+        args: deno_core::v8::FunctionCallbackArguments,
+        mut rv: deno_core::v8::ReturnValue,
+    ) {
+        let ctx = unsafe {
+            &*(deno_core::v8::Local::<deno_core::v8::External>::cast(args.data()).value()
+                as *const deno_core::_ops::OpCtx)
+        };
+        {
+            let op_state = &mut std::cell::RefCell::borrow_mut(&ctx.state);
+            if let Some(err) = op_state.last_fast_op_error.take() {
+                let exception = deno_core::error::to_v8_error(
+                    scope,
+                    op_state.get_error_class_fn,
+                    &err,
+                );
+                scope.throw_exception(exception);
+                return;
+            }
+        }
+        let arg_0 = match deno_core::v8::Local::<
+            deno_core::v8::String,
+        >::try_from(args.get(0usize as i32)) {
+            Ok(v8_string) => deno_core::serde_v8::to_utf8(v8_string, scope),
+            Err(_) => {
+                return deno_core::_ops::throw_type_error(
+                    scope,
+                    format!("Expected string at position {}", 0usize),
+                );
+            }
+        };
+        let arg_0 = arg_0.as_ref();
+        let arg_1 = args.get(1usize as i32);
+        let arg_1 = match deno_core::serde_v8::from_v8(scope, arg_1) {
+            Ok(v) => v,
+            Err(err) => {
+                let msg = format!(
+                    "Error parsing args at position {}: {}", 1usize,
+                    deno_core::anyhow::Error::from(err)
+                );
+                return deno_core::_ops::throw_type_error(scope, msg);
+            }
+        };
+        let result = Self::call(
+            &mut std::cell::RefCell::borrow_mut(&ctx.state),
+            arg_0,
+            arg_1,
+        );
+        let op_state = ::std::cell::RefCell::borrow(&*ctx.state);
+        op_state.tracker.track_sync(ctx.id);
+        match result {
+            Ok(result) => {}
+            Err(err) => {
+                let exception = deno_core::error::to_v8_error(
+                    scope,
+                    op_state.get_error_class_fn,
+                    &err,
+                );
+                scope.throw_exception(exception);
+            }
+        };
+    }
+}
+struct op_print_fast {
+    _phantom: ::std::marker::PhantomData<()>,
+}
+impl<'scope> deno_core::v8::fast_api::FastFunction for op_print_fast {
+    fn function(&self) -> *const ::std::ffi::c_void {
+        op_print_fast_fn as *const ::std::ffi::c_void
+    }
+    fn args(&self) -> &'static [deno_core::v8::fast_api::Type] {
+        use deno_core::v8::fast_api::Type::*;
+        use deno_core::v8::fast_api::CType;
+        &[V8Value, SeqOneByteString, Bool, CallbackOptions]
+    }
+    fn return_type(&self) -> deno_core::v8::fast_api::CType {
+        deno_core::v8::fast_api::CType::Void
+    }
+}
+fn op_print_fast_fn<'scope>(
+    _: deno_core::v8::Local<deno_core::v8::Object>,
+    msg: *const deno_core::v8::fast_api::FastApiOneByteString,
+    is_err: bool,
+    fast_api_callback_options: *mut deno_core::v8::fast_api::FastApiCallbackOptions,
+) -> () {
+    use deno_core::v8;
+    use deno_core::_ops;
+    let __opts: &mut v8::fast_api::FastApiCallbackOptions = unsafe {
+        &mut *fast_api_callback_options
+    };
+    let __ctx = unsafe {
+        &*(v8::Local::<v8::External>::cast(unsafe { __opts.data.data }).value()
+            as *const _ops::OpCtx)
+    };
+    let state = &mut ::std::cell::RefCell::borrow_mut(&__ctx.state);
+    let msg = unsafe { &*msg }.as_str();
+    let result = op_print::call(state, msg, is_err);
+    match result {
+        Ok(result) => result,
+        Err(err) => {
+            state.last_fast_op_error.replace(err);
+            __opts.fallback = true;
+            Default::default()
+        }
+    }
+}
diff --git a/ops/optimizer_tests/op_print.rs b/ops/optimizer_tests/op_print.rs
new file mode 100644
index 000000000..516521a0e
--- /dev/null
+++ b/ops/optimizer_tests/op_print.rs
@@ -0,0 +1,6 @@
+fn op_print(
+  state: &mut OpState,
+  msg: &str,
+  is_err: bool,
+) -> Result<(), AnyError> {
+}
diff --git a/ops/optimizer_tests/owned_string.expected b/ops/optimizer_tests/owned_string.expected
new file mode 100644
index 000000000..a15275412
--- /dev/null
+++ b/ops/optimizer_tests/owned_string.expected
@@ -0,0 +1,11 @@
+=== Optimizer Dump ===
+returns_result: false
+has_ref_opstate: false
+has_rc_opstate: false
+has_fast_callback_option: false
+needs_fast_callback_option: false
+fast_result: Some(U32)
+fast_parameters: [V8Value, SeqOneByteString]
+transforms: {0: Transform { kind: SeqOneByteString(Owned), index: 0 }}
+is_async: false
+fast_compatible: true
diff --git a/ops/optimizer_tests/owned_string.out b/ops/optimizer_tests/owned_string.out
new file mode 100644
index 000000000..4892221f8
--- /dev/null
+++ b/ops/optimizer_tests/owned_string.out
@@ -0,0 +1,99 @@
+#[allow(non_camel_case_types)]
+///Auto-generated by `deno_ops`, i.e: `#[op]`
+///
+///Use `op_string_length::decl()` to get an op-declaration
+///you can include in a `deno_core::Extension`.
+pub struct op_string_length;
+#[doc(hidden)]
+impl op_string_length {
+    pub fn name() -> &'static str {
+        stringify!(op_string_length)
+    }
+    pub fn v8_fn_ptr<'scope>() -> deno_core::v8::FunctionCallback {
+        use deno_core::v8::MapFnTo;
+        Self::v8_func.map_fn_to()
+    }
+    pub fn decl<'scope>() -> deno_core::OpDecl {
+        deno_core::OpDecl {
+            name: Self::name(),
+            v8_fn_ptr: Self::v8_fn_ptr(),
+            enabled: true,
+            fast_fn: Some(
+                Box::new(op_string_length_fast {
+                    _phantom: ::std::marker::PhantomData,
+                }),
+            ),
+            is_async: false,
+            is_unstable: false,
+            is_v8: false,
+            argc: 1usize,
+        }
+    }
+    #[inline]
+    #[allow(clippy::too_many_arguments)]
+    fn call(string: String) -> u32 {
+        string.len() as u32
+    }
+    pub fn v8_func<'scope>(
+        scope: &mut deno_core::v8::HandleScope<'scope>,
+        args: deno_core::v8::FunctionCallbackArguments,
+        mut rv: deno_core::v8::ReturnValue,
+    ) {
+        let ctx = unsafe {
+            &*(deno_core::v8::Local::<deno_core::v8::External>::cast(args.data()).value()
+                as *const deno_core::_ops::OpCtx)
+        };
+        let arg_0 = match deno_core::v8::Local::<
+            deno_core::v8::String,
+        >::try_from(args.get(0usize as i32)) {
+            Ok(v8_string) => deno_core::serde_v8::to_utf8(v8_string, scope),
+            Err(_) => {
+                return deno_core::_ops::throw_type_error(
+                    scope,
+                    format!("Expected string at position {}", 0usize),
+                );
+            }
+        };
+        let result = Self::call(arg_0);
+        let op_state = ::std::cell::RefCell::borrow(&*ctx.state);
+        op_state.tracker.track_sync(ctx.id);
+        match deno_core::serde_v8::to_v8(scope, result) {
+            Ok(ret) => rv.set(ret),
+            Err(err) => {
+                deno_core::_ops::throw_type_error(
+                    scope,
+                    format!(
+                        "Error serializing return: {}",
+                        deno_core::anyhow::Error::from(err)
+                    ),
+                )
+            }
+        };
+    }
+}
+struct op_string_length_fast {
+    _phantom: ::std::marker::PhantomData<()>,
+}
+impl<'scope> deno_core::v8::fast_api::FastFunction for op_string_length_fast {
+    fn function(&self) -> *const ::std::ffi::c_void {
+        op_string_length_fast_fn as *const ::std::ffi::c_void
+    }
+    fn args(&self) -> &'static [deno_core::v8::fast_api::Type] {
+        use deno_core::v8::fast_api::Type::*;
+        use deno_core::v8::fast_api::CType;
+        &[V8Value, SeqOneByteString]
+    }
+    fn return_type(&self) -> deno_core::v8::fast_api::CType {
+        deno_core::v8::fast_api::CType::Uint32
+    }
+}
+fn op_string_length_fast_fn<'scope>(
+    _: deno_core::v8::Local<deno_core::v8::Object>,
+    string: *const deno_core::v8::fast_api::FastApiOneByteString,
+) -> u32 {
+    use deno_core::v8;
+    use deno_core::_ops;
+    let string = unsafe { &*string }.as_str().to_owned();
+    let result = op_string_length::call(string);
+    result
+}
diff --git a/ops/optimizer_tests/owned_string.rs b/ops/optimizer_tests/owned_string.rs
new file mode 100644
index 000000000..102cf00fb
--- /dev/null
+++ b/ops/optimizer_tests/owned_string.rs
@@ -0,0 +1,3 @@
+fn op_string_length(string: String) -> u32 {
+  string.len() as u32
+}
diff --git a/ops/optimizer_tests/strings.expected b/ops/optimizer_tests/strings.expected
new file mode 100644
index 000000000..ead741054
--- /dev/null
+++ b/ops/optimizer_tests/strings.expected
@@ -0,0 +1,11 @@
+=== Optimizer Dump ===
+returns_result: false
+has_ref_opstate: false
+has_rc_opstate: false
+has_fast_callback_option: false
+needs_fast_callback_option: false
+fast_result: Some(U32)
+fast_parameters: [V8Value, SeqOneByteString]
+transforms: {0: Transform { kind: SeqOneByteString(Ref), index: 0 }}
+is_async: false
+fast_compatible: true
diff --git a/ops/optimizer_tests/strings.out b/ops/optimizer_tests/strings.out
new file mode 100644
index 000000000..41f09c4f8
--- /dev/null
+++ b/ops/optimizer_tests/strings.out
@@ -0,0 +1,100 @@
+#[allow(non_camel_case_types)]
+///Auto-generated by `deno_ops`, i.e: `#[op]`
+///
+///Use `op_string_length::decl()` to get an op-declaration
+///you can include in a `deno_core::Extension`.
+pub struct op_string_length;
+#[doc(hidden)]
+impl op_string_length {
+    pub fn name() -> &'static str {
+        stringify!(op_string_length)
+    }
+    pub fn v8_fn_ptr<'scope>() -> deno_core::v8::FunctionCallback {
+        use deno_core::v8::MapFnTo;
+        Self::v8_func.map_fn_to()
+    }
+    pub fn decl<'scope>() -> deno_core::OpDecl {
+        deno_core::OpDecl {
+            name: Self::name(),
+            v8_fn_ptr: Self::v8_fn_ptr(),
+            enabled: true,
+            fast_fn: Some(
+                Box::new(op_string_length_fast {
+                    _phantom: ::std::marker::PhantomData,
+                }),
+            ),
+            is_async: false,
+            is_unstable: false,
+            is_v8: false,
+            argc: 1usize,
+        }
+    }
+    #[inline]
+    #[allow(clippy::too_many_arguments)]
+    fn call(string: &str) -> u32 {
+        string.len() as u32
+    }
+    pub fn v8_func<'scope>(
+        scope: &mut deno_core::v8::HandleScope<'scope>,
+        args: deno_core::v8::FunctionCallbackArguments,
+        mut rv: deno_core::v8::ReturnValue,
+    ) {
+        let ctx = unsafe {
+            &*(deno_core::v8::Local::<deno_core::v8::External>::cast(args.data()).value()
+                as *const deno_core::_ops::OpCtx)
+        };
+        let arg_0 = match deno_core::v8::Local::<
+            deno_core::v8::String,
+        >::try_from(args.get(0usize as i32)) {
+            Ok(v8_string) => deno_core::serde_v8::to_utf8(v8_string, scope),
+            Err(_) => {
+                return deno_core::_ops::throw_type_error(
+                    scope,
+                    format!("Expected string at position {}", 0usize),
+                );
+            }
+        };
+        let arg_0 = arg_0.as_ref();
+        let result = Self::call(arg_0);
+        let op_state = ::std::cell::RefCell::borrow(&*ctx.state);
+        op_state.tracker.track_sync(ctx.id);
+        match deno_core::serde_v8::to_v8(scope, result) {
+            Ok(ret) => rv.set(ret),
+            Err(err) => {
+                deno_core::_ops::throw_type_error(
+                    scope,
+                    format!(
+                        "Error serializing return: {}",
+                        deno_core::anyhow::Error::from(err)
+                    ),
+                )
+            }
+        };
+    }
+}
+struct op_string_length_fast {
+    _phantom: ::std::marker::PhantomData<()>,
+}
+impl<'scope> deno_core::v8::fast_api::FastFunction for op_string_length_fast {
+    fn function(&self) -> *const ::std::ffi::c_void {
+        op_string_length_fast_fn as *const ::std::ffi::c_void
+    }
+    fn args(&self) -> &'static [deno_core::v8::fast_api::Type] {
+        use deno_core::v8::fast_api::Type::*;
+        use deno_core::v8::fast_api::CType;
+        &[V8Value, SeqOneByteString]
+    }
+    fn return_type(&self) -> deno_core::v8::fast_api::CType {
+        deno_core::v8::fast_api::CType::Uint32
+    }
+}
+fn op_string_length_fast_fn<'scope>(
+    _: deno_core::v8::Local<deno_core::v8::Object>,
+    string: *const deno_core::v8::fast_api::FastApiOneByteString,
+) -> u32 {
+    use deno_core::v8;
+    use deno_core::_ops;
+    let string = unsafe { &*string }.as_str();
+    let result = op_string_length::call(string);
+    result
+}
diff --git a/ops/optimizer_tests/strings.rs b/ops/optimizer_tests/strings.rs
new file mode 100644
index 000000000..860f1e8ec
--- /dev/null
+++ b/ops/optimizer_tests/strings.rs
@@ -0,0 +1,3 @@
+fn op_string_length(string: &str) -> u32 {
+  string.len() as u32
+}
diff --git a/runtime/ops/fs.rs b/runtime/ops/fs.rs
index ebd24ebe0..8d719393f 100644
--- a/runtime/ops/fs.rs
+++ b/runtime/ops/fs.rs
@@ -524,13 +524,13 @@ fn op_umask(state: &mut OpState, mask: Option<u32>) -> Result<u32, AnyError> {
 }
 
 #[op]
-fn op_chdir(state: &mut OpState, directory: String) -> Result<(), AnyError> {
+fn op_chdir(state: &mut OpState, directory: &str) -> Result<(), AnyError> {
   let d = PathBuf::from(&directory);
   state
     .borrow_mut::<Permissions>()
     .read
     .check(&d, Some("Deno.chdir()"))?;
-  set_current_dir(&d).map_err(|err| {
+  set_current_dir(d).map_err(|err| {
     Error::new(err.kind(), format!("{}, chdir '{}'", err, directory))
   })?;
   Ok(())
@@ -603,10 +603,10 @@ async fn op_mkdir_async(
 #[op]
 fn op_chmod_sync(
   state: &mut OpState,
-  path: String,
+  path: &str,
   mode: u32,
 ) -> Result<(), AnyError> {
-  let path = Path::new(&path);
+  let path = Path::new(path);
   let mode = mode & 0o777;
 
   state
@@ -661,11 +661,11 @@ fn raw_chmod(path: &Path, _raw_mode: u32) -> Result<(), AnyError> {
 #[op]
 fn op_chown_sync(
   state: &mut OpState,
-  path: String,
+  path: &str,
   #[cfg_attr(windows, allow(unused_variables))] uid: Option<u32>,
   #[cfg_attr(windows, allow(unused_variables))] gid: Option<u32>,
 ) -> Result<(), AnyError> {
-  let path = Path::new(&path).to_path_buf();
+  let path = Path::new(path).to_path_buf();
   state
     .borrow_mut::<Permissions>()
     .write
@@ -734,10 +734,10 @@ async fn op_chown_async(
 #[op]
 fn op_remove_sync(
   state: &mut OpState,
-  path: String,
+  path: &str,
   recursive: bool,
 ) -> Result<(), AnyError> {
-  let path = PathBuf::from(&path);
+  let path = PathBuf::from(path);
 
   state
     .borrow_mut::<Permissions>()
@@ -835,11 +835,11 @@ async fn op_remove_async(
 #[op]
 fn op_copy_file_sync(
   state: &mut OpState,
-  from: String,
-  to: String,
+  from: &str,
+  to: &str,
 ) -> Result<(), AnyError> {
-  let from_path = PathBuf::from(&from);
-  let to_path = PathBuf::from(&to);
+  let from_path = PathBuf::from(from);
+  let to_path = PathBuf::from(to);
 
   let permissions = state.borrow_mut::<Permissions>();
   permissions
@@ -1097,11 +1097,11 @@ pub struct StatArgs {
 #[op]
 fn op_stat_sync(
   state: &mut OpState,
-  path: String,
+  path: &str,
   lstat: bool,
   out_buf: &mut [u32],
 ) -> Result<(), AnyError> {
-  let path = PathBuf::from(&path);
+  let path = PathBuf::from(path);
   state
     .borrow_mut::<Permissions>()
     .read
@@ -1313,11 +1313,11 @@ async fn op_read_dir_async(
 #[op]
 fn op_rename_sync(
   state: &mut OpState,
-  oldpath: String,
-  newpath: String,
+  oldpath: &str,
+  newpath: &str,
 ) -> Result<(), AnyError> {
-  let oldpath = PathBuf::from(&oldpath);
-  let newpath = PathBuf::from(&newpath);
+  let oldpath = PathBuf::from(oldpath);
+  let newpath = PathBuf::from(newpath);
 
   let permissions = state.borrow_mut::<Permissions>();
   permissions
@@ -1382,11 +1382,11 @@ async fn op_rename_async(
 #[op]
 fn op_link_sync(
   state: &mut OpState,
-  oldpath: String,
-  newpath: String,
+  oldpath: &str,
+  newpath: &str,
 ) -> Result<(), AnyError> {
-  let oldpath = PathBuf::from(&oldpath);
-  let newpath = PathBuf::from(&newpath);
+  let oldpath = PathBuf::from(oldpath);
+  let newpath = PathBuf::from(newpath);
 
   let permissions = state.borrow_mut::<Permissions>();
   permissions.read.check(&oldpath, Some("Deno.linkSync()"))?;
@@ -1449,12 +1449,12 @@ async fn op_link_async(
 #[op]
 fn op_symlink_sync(
   state: &mut OpState,
-  oldpath: String,
-  newpath: String,
+  oldpath: &str,
+  newpath: &str,
   _type: Option<String>,
 ) -> Result<(), AnyError> {
-  let oldpath = PathBuf::from(&oldpath);
-  let newpath = PathBuf::from(&newpath);
+  let oldpath = PathBuf::from(oldpath);
+  let newpath = PathBuf::from(newpath);
 
   state
     .borrow_mut::<Permissions>()
@@ -1669,10 +1669,10 @@ async fn op_ftruncate_async(
 #[op]
 fn op_truncate_sync(
   state: &mut OpState,
-  path: String,
+  path: &str,
   len: u64,
 ) -> Result<(), AnyError> {
-  let path = PathBuf::from(&path);
+  let path = PathBuf::from(path);
 
   state
     .borrow_mut::<Permissions>()
@@ -1949,13 +1949,13 @@ async fn op_futime_async(
 #[op]
 fn op_utime_sync(
   state: &mut OpState,
-  path: String,
+  path: &str,
   atime_secs: i64,
   atime_nanos: u32,
   mtime_secs: i64,
   mtime_nanos: u32,
 ) -> Result<(), AnyError> {
-  let path = PathBuf::from(&path);
+  let path = PathBuf::from(path);
   let atime = filetime::FileTime::from_unix_time(atime_secs, atime_nanos);
   let mtime = filetime::FileTime::from_unix_time(mtime_secs, mtime_nanos);
 
diff --git a/runtime/ops/io.rs b/runtime/ops/io.rs
index 8ed6969f9..fd5b8a962 100644
--- a/runtime/ops/io.rs
+++ b/runtime/ops/io.rs
@@ -671,7 +671,7 @@ impl Resource for StdFileResource {
 #[op]
 pub fn op_print(
   state: &mut OpState,
-  msg: String,
+  msg: &str,
   is_err: bool,
 ) -> Result<(), AnyError> {
   let rid = if is_err { 2 } else { 1 };
diff --git a/runtime/ops/os/mod.rs b/runtime/ops/os/mod.rs
index b93935955..844fbaecc 100644
--- a/runtime/ops/os/mod.rs
+++ b/runtime/ops/os/mod.rs
@@ -78,10 +78,10 @@ fn op_exec_path(state: &mut OpState) -> Result<String, AnyError> {
 #[op]
 fn op_set_env(
   state: &mut OpState,
-  key: String,
-  value: String,
+  key: &str,
+  value: &str,
 ) -> Result<(), AnyError> {
-  state.borrow_mut::<Permissions>().env.check(&key)?;
+  state.borrow_mut::<Permissions>().env.check(key)?;
   if key.is_empty() {
     return Err(type_error("Key is an empty string."));
   }
diff --git a/runtime/ops/signal.rs b/runtime/ops/signal.rs
index 95c166787..66530a838 100644
--- a/runtime/ops/signal.rs
+++ b/runtime/ops/signal.rs
@@ -453,9 +453,9 @@ pub fn signal_int_to_str(s: libc::c_int) -> Result<&'static str, AnyError> {
 #[op]
 fn op_signal_bind(
   state: &mut OpState,
-  sig: String,
+  sig: &str,
 ) -> Result<ResourceId, AnyError> {
-  let signo = signal_str_to_int(&sig)?;
+  let signo = signal_str_to_int(sig)?;
   if signal_hook_registry::FORBIDDEN.contains(&signo) {
     return Err(type_error(format!(
       "Binding to signal '{}' is not allowed",
@@ -474,9 +474,9 @@ fn op_signal_bind(
 #[op]
 fn op_signal_bind(
   state: &mut OpState,
-  sig: String,
+  sig: &str,
 ) -> Result<ResourceId, AnyError> {
-  let signo = signal_str_to_int(&sig)?;
+  let signo = signal_str_to_int(sig)?;
   let resource = SignalStreamResource {
     signal: AsyncRefCell::new(match signo {
       // SIGINT