register aliases instead of clone

Author: burrbull

src/generate/peripheral.rs

@@ -877,10 +877,9 @@ fn render_ercs(
                     rpath = derive_register(reg, &dpath, path, index)?;
                 }
                 let reg_name = &reg.name;
-                let rpath = rpath.unwrap_or_else(|| path.new_register(reg_name));
 
-                let rendered_reg =
-                    register::render(reg, &rpath, index, config).with_context(|| {
+                let rendered_reg = register::render(reg, path, &rpath, index, config)
+                    .with_context(|| {
                         let descrip = reg.description.as_deref().unwrap_or("No description");
                         format!(
                             "Error rendering register\nName: {reg_name}\nDescription: {descrip}"

src/generate/register.rs

@@ -9,14 +9,79 @@ use proc_macro2::{Ident, Punct, Spacing, Span, TokenStream};
 use quote::{quote, ToTokens};
 use std::collections::HashSet;
 use svd_parser::expand::{
-    derive_enumerated_values, derive_field, EnumPath, FieldPath, Index, RegisterPath,
+    derive_enumerated_values, derive_field, BlockPath, EnumPath, FieldPath, Index, RegisterPath,
 };
 
 use crate::util::{self, ident_to_path, path_segment, type_path, Config, ToSanitizedCase, U32Ext};
 use anyhow::{anyhow, Result};
 use syn::punctuated::Punctuated;
 
 pub fn render(
+    register: &Register,
+    path: &BlockPath,
+    dpath: &Option<RegisterPath>,
+    index: &Index,
+    config: &Config,
+) -> Result<TokenStream> {
+    let mut out = TokenStream::new();
+    let name = util::name_of(register, config.ignore_groups);
+    let span = Span::call_site();
+    let name_constant_case = name.to_constant_case_ident(span);
+    let name_constant_case_spec = format!("{name}_SPEC").to_constant_case_ident(span);
+    let name_snake_case = name.to_snake_case_ident(span);
+    let description = util::escape_brackets(
+        util::respace(&register.description.clone().unwrap_or_else(|| {
+            warn!("Missing description for register {}", register.name);
+            Default::default()
+        }))
+        .as_ref(),
+    );
+    let alias_doc =
+        format!("{name} register accessor: an alias for `Reg<{name_constant_case_spec}>`");
+    let wrapped_name = util::name_to_wrapped_ty(&name);
+    out.extend(quote! {
+        #[doc = #alias_doc]
+        pub type #name_constant_case = #wrapped_name;
+    });
+
+    let mod_items = if let Some(dpath) = dpath {
+        let mut mod_items = TokenStream::new();
+        let mut derived_spec = if &dpath.block == path {
+            let mut segments = Punctuated::new();
+            segments.push(path_segment(Ident::new("super", span)));
+            type_path(segments)
+        } else {
+            util::block_path_to_ty(&dpath.block, span)
+        };
+        let dname = util::name_of(index.registers.get(dpath).unwrap(), config.ignore_groups);
+        derived_spec
+            .path
+            .segments
+            .push(path_segment(dname.to_snake_case_ident(span)));
+        derived_spec.path.segments.push(path_segment(
+            format!("{}_SPEC", dname).to_constant_case_ident(span),
+        ));
+
+        mod_items.extend(quote! {
+            #[doc = #description]
+            pub use #derived_spec as #name_constant_case_spec;
+        });
+        mod_items
+    } else {
+        render_register_mod(register, &path.new_register(&register.name), index, config)?
+    };
+
+    out.extend(quote! {
+        #[doc = #description]
+        pub mod #name_snake_case {
+            #mod_items
+        }
+    });
+
+    Ok(out)
+}
+
+pub fn render_register_mod(
     register: &Register,
     path: &RegisterPath,
     index: &Index,
@@ -26,7 +91,6 @@ pub fn render(
     let access = util::access_of(properties, register.fields.as_deref());
     let name = util::name_of(register, config.ignore_groups);
     let span = Span::call_site();
-    let name_constant_case = name.to_constant_case_ident(span);
     let name_constant_case_spec = format!("{name}_SPEC").to_constant_case_ident(span);
     let name_snake_case = name.to_snake_case_ident(span);
     let rsize = properties
@@ -285,28 +349,7 @@ pub fn render(
             }
         });
     }
-
-    let mut out = TokenStream::new();
-    let alias_doc =
-        format!("{name} register accessor: an alias for `Reg<{name_constant_case_spec}>`");
-    let wrapped_name = util::name_to_wrapped_ty(&name);
-    out.extend(quote! {
-        #[doc = #alias_doc]
-        pub type #name_constant_case = #wrapped_name;
-    });
-
-    out.extend(quote! {
-        #[doc = #description]
-        pub mod #name_snake_case #open
-    });
-
-    out.extend(mod_items);
-
-    out.extend(quote! {
-        #close
-    });
-
-    Ok(out)
+    Ok(mod_items)
 }
 
 #[allow(clippy::too_many_arguments)]