Validate export_name attribute

Author: nagisa

src/librustc_trans/trans/base.rs

@@ -1692,9 +1692,9 @@ pub fn build_return_block<'blk, 'tcx>(fcx: &FunctionContext<'blk, 'tcx>,
     }
 }
 
-// trans_closure: Builds an LLVM function out of a source function.
-// If the function closes over its environment a closure will be
-// returned.
+/// Builds an LLVM function out of a source function.
+///
+/// If the function closes over its environment a closure will be returned.
 pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                                    decl: &ast::FnDecl,
                                    body: &ast::Block,
@@ -1827,8 +1827,7 @@ pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     finish_fn(&fcx, bcx, output_type, ret_debug_loc);
 }
 
-// trans_fn: creates an LLVM function corresponding to a source language
-// function.
+/// Creates an LLVM function corresponding to a source language function.
 pub fn trans_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                           decl: &ast::FnDecl,
                           body: &ast::Block,
@@ -2645,10 +2644,9 @@ fn exported_name<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, id: ast::NodeId,
         None => {}
     }
 
-    match attr::first_attr_value_str_by_name(attrs, "export_name") {
+    match attr::find_export_name_attr(ccx.sess().diagnostic(), attrs) {
         // Use provided name
         Some(name) => name.to_string(),
-
         _ => ccx.tcx().map.with_path(id, |path| {
             if attr::contains_name(attrs, "no_mangle") {
                 // Don't mangle

src/libsyntax/attr.rs

@@ -282,6 +282,23 @@ pub fn find_crate_name(attrs: &[Attribute]) -> Option<InternedString> {
     first_attr_value_str_by_name(attrs, "crate_name")
 }
 
+/// Find the value of #[export_name=*] attribute and check its validity.
+pub fn find_export_name_attr(diag: &SpanHandler, attrs: &[Attribute]) -> Option<InternedString> {
+    attrs.iter().fold(None, |ia,attr| {
+        if attr.check_name("export_name") {
+            if let s@Some(_) = attr.value_str() {
+                s
+            } else {
+                diag.span_err(attr.span, "export_name attribute has invalid format");
+                diag.handler.help("use #[export_name=\"*\"]");
+                None
+            }
+        } else {
+            ia
+        }
+    })
+}
+
 #[derive(Copy, Clone, PartialEq)]
 pub enum InlineAttr {
     None,