Use link_name for dynamic library loading

Author: Molot2032

bindgen/codegen/dyngen.rs

@@ -131,6 +131,7 @@ impl DynamicItems {
     pub(crate) fn push_func(
         &mut self,
         ident: Ident,
+        symbol: &str,
         abi: ClangAbi,
         is_variadic: bool,
         is_required: bool,
@@ -181,11 +182,12 @@ impl DynamicItems {
         }
 
         // N.B: Unwrap the signature upon construction if it is required to be resolved.
-        let ident_str = codegen::helpers::ast_ty::cstr_expr(ident.to_string());
+        let symbol_cstr =
+            codegen::helpers::ast_ty::cstr_expr(symbol.to_string());
         let library_get = if ctx.options().wrap_unsafe_ops {
-            quote!(unsafe { __library.get(#ident_str) })
+            quote!(unsafe { __library.get(#symbol_cstr) })
         } else {
-            quote!(__library.get(#ident_str))
+            quote!(__library.get(#symbol_cstr))
         };
 
         self.constructor_inits.push(if is_required {
@@ -206,6 +208,7 @@ impl DynamicItems {
     pub fn push_var(
         &mut self,
         ident: Ident,
+        symbol: &str,
         ty: TokenStream,
         is_required: bool,
         wrap_unsafe_ops: bool,
@@ -231,12 +234,13 @@ impl DynamicItems {
             }
         });
 
-        let ident_str = codegen::helpers::ast_ty::cstr_expr(ident.to_string());
+        let symbol_cstr =
+            codegen::helpers::ast_ty::cstr_expr(symbol.to_string());
 
         let library_get = if wrap_unsafe_ops {
-            quote!(unsafe { __library.get::<*mut #ty>(#ident_str) })
+            quote!(unsafe { __library.get::<*mut #ty>(#symbol_cstr) })
         } else {
-            quote!(__library.get::<*mut #ty>(#ident_str))
+            quote!(__library.get::<*mut #ty>(#symbol_cstr))
         };
 
         let qmark = if is_required { quote!(?) } else { quote!() };

bindgen/codegen/mod.rs

@@ -779,17 +779,25 @@ impl CodeGenerator for Var {
                 }
             }
         } else {
-            // If necessary, apply a `#[link_name]` attribute
-            if let Some(link_name) = self.link_name() {
-                attrs.push(attributes::link_name::<false>(link_name));
-            } else {
-                let link_name =
-                    self.mangled_name().unwrap_or_else(|| self.name());
-                if !utils::names_will_be_identical_after_mangling(
-                    &canonical_name,
-                    link_name,
-                    None,
-                ) {
+            // None means the canonical name will end up working out the same, so no need to add the attribute.
+            let link_name_attribute: Option<&str> =
+                self.link_name().or_else(|| {
+                    let link_name =
+                        self.mangled_name().unwrap_or_else(|| self.name());
+                    if utils::names_will_be_identical_after_mangling(
+                        &canonical_name,
+                        link_name,
+                        None,
+                    ) {
+                        None
+                    } else {
+                        Some(link_name)
+                    }
+                });
+
+            // Apply the `#[link_name]` attribute if necessary, but not if we're not generating dynamic library bindings as they're linked at runtime.
+            if let Some(link_name) = link_name_attribute {
+                if ctx.options().dynamic_library_name.is_none() {
                     attrs.push(attributes::link_name::<false>(link_name));
                 }
             }
@@ -814,8 +822,10 @@ impl CodeGenerator for Var {
             );
 
             if ctx.options().dynamic_library_name.is_some() {
+                let symbol = link_name_attribute.unwrap_or(&canonical_name);
                 result.dynamic_items().push_var(
                     canonical_ident,
+                    symbol,
                     self.ty()
                         .to_rust_ty_or_opaque(ctx, &())
                         .into_token_stream(),
@@ -4641,21 +4651,19 @@ impl CodeGenerator for Function {
             write!(&mut canonical_name, "{times_seen}").unwrap();
         }
 
-        let mut has_link_name_attr = false;
-        if let Some(link_name) = self.link_name() {
-            attributes.push(attributes::link_name::<false>(link_name));
-            has_link_name_attr = true;
-        } else {
-            let link_name = mangled_name.unwrap_or(name);
-            if !is_dynamic_function &&
-                !utils::names_will_be_identical_after_mangling(
-                    &canonical_name,
-                    link_name,
-                    Some(abi),
-                )
-            {
+        let link_name_attr = self.link_name().or_else(|| {
+            let mangled_name = mangled_name.unwrap_or(name);
+            (!utils::names_will_be_identical_after_mangling(
+                &canonical_name,
+                mangled_name,
+                Some(abi),
+            ))
+            .then(|| mangled_name)
+        });
+
+        if let Some(link_name) = link_name_attr {
+            if ctx.options().dynamic_library_name.is_none() {
                 attributes.push(attributes::link_name::<false>(link_name));
-                has_link_name_attr = true;
             }
         }
 
@@ -4667,8 +4675,9 @@ impl CodeGenerator for Function {
                 quote! { #[link(wasm_import_module = #name)] }
             });
 
-        let should_wrap =
-            is_internal && ctx.options().wrap_static_fns && !has_link_name_attr;
+        let should_wrap = is_internal &&
+            ctx.options().wrap_static_fns &&
+            link_name_attr.is_none();
 
         if should_wrap {
             let name = canonical_name.clone() + ctx.wrap_static_fns_suffix();
@@ -4734,11 +4743,14 @@ impl CodeGenerator for Function {
 
         // If we're doing dynamic binding generation, add to the dynamic items.
         if is_dynamic_function {
+            let ident_str = ident.to_string();
+            let symbol = link_name_attr.unwrap_or(&ident_str);
             let args_identifiers =
                 utils::fnsig_argument_identifiers(ctx, signature);
             let ret_ty = utils::fnsig_return_ty(ctx, signature);
             result.dynamic_items().push_func(
                 ident,
+                symbol,
                 abi,
                 signature.is_variadic(),
                 ctx.options().dynamic_link_require_all,