Add standalone code generation support for the Rust Standard Library (#2439)

Author: kennykerr

crates/libs/bindgen/src/constants.rs

@@ -39,12 +39,15 @@ pub fn gen(gen: &Gen, def: Field) -> TokenStream {
         } else {
             let kind = gen.type_default_name(&ty);
             let value = gen.value(&gen.reader.constant_value(constant));
+            let underlying_type = gen.reader.type_underlying_type(&ty);
 
-            let value = if gen.reader.type_underlying_type(&ty) == constant_type {
+            let value = if underlying_type == constant_type {
                 value
             // TODO: workaround for https://github.com/microsoft/win32metadata/issues/1029
             } else if ty == Type::PCWSTR && value.0.starts_with('-') {
                 quote! { #value as u16 as _ }
+            } else if gen.std && underlying_type == Type::ISize {
+                quote! { ::core::ptr::invalid_mut(#value as _) }
             } else {
                 quote! { #value as _ }
             };

crates/libs/bindgen/src/functions.rs

@@ -16,12 +16,7 @@ fn gen_sys_function(gen: &Gen, def: MethodDef) -> TokenStream {
     let features = gen.cfg_features(&cfg);
     let return_type = gen.return_sig(&signature);
     let abi = gen.reader.method_def_extern_abi(def);
-    let impl_map = gen
-        .reader
-        .method_def_impl_map(def)
-        .expect("ImplMap not found");
-    let scope = gen.reader.impl_map_scope(impl_map);
-    let link = gen.reader.module_ref_name(scope).to_lowercase();
+    let link = gen.reader.method_def_module_name(def);
 
     // TODO: skip inline functions for now.
     if link == "forceinline" {
@@ -35,14 +30,26 @@ fn gen_sys_function(gen: &Gen, def: MethodDef) -> TokenStream {
     });
 
     let mut tokens = features;
-    tokens.combine(&gen_link(
-        &link,
-        abi,
-        doc.as_str(),
-        name.as_str(),
-        params,
-        return_type.as_str(),
-    ));
+
+    if gen.std {
+        let link = link.trim_end_matches(".dll");
+        tokens.combine(&quote! {
+            #[link(name = #link)]
+            extern #abi {
+                pub fn #name(#(#params),*) #return_type;
+            }
+        });
+    } else {
+        tokens.combine(&gen_link(
+            &link,
+            abi,
+            doc.as_str(),
+            name.as_str(),
+            params,
+            return_type.as_str(),
+        ));
+    }
+
     tokens
 }
 
@@ -96,12 +103,7 @@ fn gen_win_function(gen: &Gen, def: MethodDef) -> TokenStream {
             }
         }
     } else {
-        let impl_map = gen
-            .reader
-            .method_def_impl_map(def)
-            .expect("ImplMap not found");
-        let scope = gen.reader.impl_map_scope(impl_map);
-        let link = gen.reader.module_ref_name(scope).to_lowercase();
+        let link = gen.reader.method_def_module_name(def);
 
         // TODO: skip inline functions for now.
         if link == "forceinline" {

crates/libs/bindgen/src/gen.rs

@@ -8,6 +8,7 @@ pub struct Gen<'a> {
     pub doc: bool,
     pub component: bool,
     pub standalone: bool,
+    pub std: bool,
 }
 
 impl<'a> Gen<'a> {
@@ -20,6 +21,7 @@ impl<'a> Gen<'a> {
             doc: false,
             component: false,
             standalone: false,
+            std: false,
         }
     }
 

crates/libs/bindgen/src/handles.rs

@@ -10,10 +10,23 @@ pub fn gen(gen: &Gen, def: TypeDef) -> TokenStream {
 
 pub fn gen_sys_handle(gen: &Gen, def: TypeDef) -> TokenStream {
     let ident = to_ident(gen.reader.type_def_name(def));
-    let signature = gen.type_default_name(&gen.reader.type_def_underlying_type(def));
+    match gen.reader.type_def_underlying_type(def) {
+        Type::ISize if gen.std => quote! {
+            pub type #ident = *mut ::core::ffi::c_void;
+        },
+        Type::USize if gen.std => quote! {
+            #[cfg(target_pointer_width = "32")]
+            pub type #ident = u32;
+            #[cfg(target_pointer_width = "64")]
+            pub type #ident = u64;
+        },
+        underlying_type => {
+            let signature = gen.type_default_name(&underlying_type);
 
-    quote! {
-        pub type #ident = #signature;
+            quote! {
+                pub type #ident = #signature;
+            }
+        }
     }
 }