Avoid infinite loop in field_reference.

From-SVN: r170457

diff --git a/gcc/go/gofrontend/types.cc b/gcc/go/gofrontend/types.cc
index 1e3973167e80fb97433b39e4c715ca34153705ed..806226f6f424253d19adba22981925c25c7501b8 100644 (file)
--- a/gcc/go/gofrontend/types.cc
+++ b/gcc/go/gofrontend/types.cc
@@ -3583,7 +3583,8 @@ Struct_type::field_reference(Expression* struct_expr, const std::string& name,
                             source_location location) const
 {
   unsigned int depth;
-  return this->field_reference_depth(struct_expr, name, location, &depth);
+  return this->field_reference_depth(struct_expr, name, location, NULL,
+                                    &depth);
 }
 
 // Return an expression for a field, along with the depth at which it
@@ -3593,6 +3594,7 @@ Field_reference_expression*
 Struct_type::field_reference_depth(Expression* struct_expr,
                                   const std::string& name,
                                   source_location location,
+                                  Saw_named_type* saw,
                                   unsigned int* depth) const
 {
   const Struct_field_list* fields = this->fields_;
@@ -3628,13 +3630,41 @@ Struct_type::field_reference_depth(Expression* struct_expr,
       if (st == NULL)
        continue;
 
+      Saw_named_type* hold_saw = saw;
+      Saw_named_type saw_here;
+      Named_type* nt = pf->type()->named_type();
+      if (nt == NULL)
+       nt = pf->type()->deref()->named_type();
+      if (nt != NULL)
+       {
+         Saw_named_type* q;
+         for (q = saw; q != NULL; q = q->next)
+           {
+             if (q->nt == nt)
+               {
+                 // If this is an error, it will be reported
+                 // elsewhere.
+                 break;
+               }
+           }
+         if (q != NULL)
+           continue;
+         saw_here.next = saw;
+         saw_here.nt = nt;
+         saw = &saw_here;
+       }
+
       // Look for a reference using a NULL struct expression.  If we
       // find one, fill in the struct expression with a reference to
       // this field.
       unsigned int subdepth;
       Field_reference_expression* sub = st->field_reference_depth(NULL, name,
                                                                  location,
+                                                                 saw,
                                                                  &subdepth);
+
+      saw = hold_saw;
+
       if (sub == NULL)
        continue;
 

diff --git a/gcc/go/gofrontend/types.h b/gcc/go/gofrontend/types.h
index b428077489864277447a7519722104e7b2fc7de4..b0dbefed4558260e7b2d2d53cff590006a4447cc 100644 (file)
--- a/gcc/go/gofrontend/types.h
+++ b/gcc/go/gofrontend/types.h
@@ -1980,9 +1980,17 @@ class Struct_type : public Type
   do_export(Export*) const;
 
  private:
+  // Used to avoid infinite loops in field_reference_depth.
+  struct Saw_named_type
+  {
+    Saw_named_type* next;
+    Named_type* nt;
+  };
+
   Field_reference_expression*
   field_reference_depth(Expression* struct_expr, const std::string& name,
-                       source_location, unsigned int* depth) const;
+                       source_location, Saw_named_type*,
+                       unsigned int* depth) const;
 
   static Type*
   make_struct_type_descriptor_type();