--- a/hotspot/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.printer/src/org/graalvm/compiler/printer/CFGPrinterObserver.java	Mon Jul 17 09:21:48 2017 -0700
+++ b/hotspot/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.printer/src/org/graalvm/compiler/printer/CFGPrinterObserver.java	Mon Jul 17 16:31:51 2017 -0700
@@ -144,7 +144,7 @@
                 OutputStream out = new BufferedOutputStream(new FileOutputStream(cfgFile));
                 cfgPrinter = new CFGPrinter(out);
             } catch (IOException e) {
-                throw (GraalError) new GraalError("Could not open %s", cfgFile.getAbsolutePath()).initCause(e);
+                throw (GraalError) new GraalError("Could not open %s", cfgFile == null ? "[null]" : cfgFile.getAbsolutePath()).initCause(e);
             }
         }