Fix issue with string options and nested gcc_jit_contexts

gcc/jit/ChangeLog:
	* jit-recording.c (gcc::jit::recording::context::context): When
	copying string options from a parent context, take a copy of the
	underlying buffers, rather than simply copying the pointer.

From-SVN: r218972

gcc/jit/ChangeLog

 2014-12-19  David Malcolm  <dmalcolm@redhat.com>
 
+	* jit-recording.c (gcc::jit::recording::context::context): When
+	copying string options from a parent context, take a copy of the
+	underlying buffers, rather than simply copying the pointer.
+
+2014-12-19  David Malcolm  <dmalcolm@redhat.com>
+
 	* jit-recording.c (gcc::jit::recording::context::set_str_option):
 	Handle NULL.
 

gcc/jit/jit-recording.c

@@ -181,11 +181,14 @@ recording::context::context (context *parent_ctxt)
 {
   if (parent_ctxt)
     {
-      /* Inherit options from parent.
-	 Note that the first memcpy means copying pointers to strings.  */
-      memcpy (m_str_options,
-	      parent_ctxt->m_str_options,
-	      sizeof (m_str_options));
+      /* Inherit options from parent.  */
+      for (unsigned i = 0;
+	   i < sizeof (m_str_options) / sizeof (m_str_options[0]);
+	   i++)
+	{
+	  const char *parent_opt = parent_ctxt->m_str_options[i];
+	  m_str_options[i] = parent_opt ? xstrdup (parent_opt) : NULL;
+	}
       memcpy (m_int_options,
 	      parent_ctxt->m_int_options,
 	      sizeof (m_int_options));