Go patch committed: Don't generate fns for private fields of structs

[Ian Lance Taylor]

When generating hash and equality functions for types, it's not
necessary to generate them for private fields of named structs defined
in different packages.  There is no way that the code can call those
functions directly anyhow.  Generating them is problematic because it
may lead to calls to functions which are not visible from the current
package.  This patch implements this fix.  Bootstrapped and ran Go
testsuite on x86_64-unknown-linux-gnu.  Committed to mainline.

Ian


diff -r 7d54213ce42e go/gogo.cc
--- a/go/gogo.cc	Thu Jan 26 12:23:11 2012 -0800
+++ b/go/gogo.cc	Thu Jan 26 13:02:49 2012 -0800
@@ -1205,13 +1205,13 @@
     {
     case Type::TYPE_NAMED:
       {
+	Named_type* nt = t->named_type();
 	if (!t->compare_is_identity(this->gogo_) && t->is_comparable())
-	  t->type_functions(this->gogo_, t->named_type(), NULL, NULL, &hash_fn,
-			    &equal_fn);
+	  t->type_functions(this->gogo_, nt, NULL, NULL, &hash_fn, &equal_fn);
 
 	// If this is a struct type, we don't want to make functions
 	// for the unnamed struct.
-	Type* rt = t->named_type()->real_type();
+	Type* rt = nt->real_type();
 	if (rt->struct_type() == NULL)
 	  {
 	    if (Type::traverse(rt, this) == TRAVERSE_EXIT)
@@ -1219,8 +1219,20 @@
 	  }
 	else
 	  {
-	    if (rt->struct_type()->traverse_field_types(this) == TRAVERSE_EXIT)
-	      return TRAVERSE_EXIT;
+	    // If this type is defined in another package, then we don't
+	    // need to worry about the unexported fields.
+	    bool is_defined_elsewhere = nt->named_object()->package() != NULL;
+	    const Struct_field_list* fields = rt->struct_type()->fields();
+	    for (Struct_field_list::const_iterator p = fields->begin();
+		 p != fields->end();
+		 ++p)
+	      {
+		if (is_defined_elsewhere
+		    && Gogo::is_hidden_name(p->field_name()))
+		  continue;
+		if (Type::traverse(p->type(), this) == TRAVERSE_EXIT)
+		  return TRAVERSE_EXIT;
+	      }
 	  }
 
 	return TRAVERSE_SKIP_COMPONENTS;