Auto merge of #1434 - emilio:attr-overloadable, r=emilio

codegen: Make the mangling name check work in presence of attribute(overloadable).

Fixes #1350

Author: bors-servo

src/codegen/mod.rs

@@ -3377,19 +3377,21 @@ impl CodeGenerator for Function {
             attributes.push(attributes::doc(comment));
         }
 
-        if let Some(mangled) = mangled_name {
-            attributes.push(attributes::link_name(mangled));
-        } else if name != canonical_name {
-            attributes.push(attributes::link_name(name));
-        }
-
         // Handle overloaded functions by giving each overload its own unique
         // suffix.
         let times_seen = result.overload_number(&canonical_name);
         if times_seen > 0 {
             write!(&mut canonical_name, "{}", times_seen).unwrap();
         }
 
+        if let Some(mangled) = mangled_name {
+            if canonical_name != mangled {
+                attributes.push(attributes::link_name(mangled));
+            }
+        } else if name != canonical_name {
+            attributes.push(attributes::link_name(name));
+        }
+
         let abi = match signature.abi() {
             Abi::ThisCall if !ctx.options().rust_features().thiscall_abi => {
                 warn!("Skipping function with thiscall ABI that isn't supported by the configured Rust target");

src/ir/function.rs

@@ -562,11 +562,7 @@ impl ClangSubItemParser for Function {
             name.push_str("_destructor");
         }
 
-        let mut mangled_name = cursor_mangling(context, &cursor);
-        if mangled_name.as_ref() == Some(&name) {
-            mangled_name = None;
-        }
-
+        let mangled_name = cursor_mangling(context, &cursor);
         let comment = cursor.raw_comment();
 
         let function = Self::new(name, mangled_name, sig, comment, kind, linkage);

tests/expectations/tests/issue-1350-attribute-overloadable.rs

@@ -0,0 +1,17 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+extern "C" {
+    #[link_name = "\u{1}_Z11my_functioni"]
+    pub fn my_function(a: ::std::os::raw::c_int);
+}
+extern "C" {
+    #[link_name = "\u{1}_Z11my_functionPKc"]
+    pub fn my_function1(a: *const ::std::os::raw::c_char);
+}

tests/headers/issue-1350-attribute-overloadable.h

@@ -0,0 +1,2 @@
+void my_function(int a) __attribute__((overloadable));
+void my_function(const char *a) __attribute__((overloadable));