Support precompiled deserialize_in_place

serde_derive/src/de.rs

@@ -1,5 +1,7 @@
 use proc_macro2::{Literal, Span, TokenStream};
 use quote::ToTokens;
+#[cfg(precompiled)]
+use std::sync::atomic::Ordering;
 use syn::punctuated::Punctuated;
 use syn::spanned::Spanned;
 use syn::{self, Ident, Index, Member};
@@ -304,6 +306,11 @@ fn deserialize_body(cont: &Container, params: &Parameters) -> Fragment {
 
 #[cfg(feature = "deserialize_in_place")]
 fn deserialize_in_place_body(cont: &Container, params: &Parameters) -> Option<Stmts> {
+    #[cfg(precompiled)]
+    if !crate::DESERIALIZE_IN_PLACE.load(Ordering::Relaxed) {
+        return None;
+    }
+
     // Only remote derives have getters, and we do not generate
     // deserialize_in_place for remote derives.
     assert!(!params.has_getter);

serde_derive/src/lib.rs

@@ -78,6 +78,8 @@ extern crate proc_macro2 as proc_macro;
 mod internals;
 
 use proc_macro::TokenStream;
+#[cfg(precompiled)]
+use std::sync::atomic::AtomicBool;
 use syn::DeriveInput;
 
 #[macro_use]
@@ -102,6 +104,9 @@ macro_rules! parse_macro_input {
     };
 }
 
+#[cfg(precompiled)]
+pub static DESERIALIZE_IN_PLACE: AtomicBool = AtomicBool::new(false);
+
 #[cfg_attr(not(precompiled), proc_macro_derive(Serialize, attributes(serde)))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {
     let mut input = parse_macro_input!(input as DeriveInput);