[d8] Make exception reporting more resilient.

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index 8c0f82a3117245f0e6e6a1202db20553d3de111b..cc62aa8cb6acdcadda0a1dbc29ee2109d0b2b97b 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -925,25 +925,28 @@ void Shell::ReportException(Isolate* isolate, v8::TryCatch* try_catch) {
     // Print (filename):(line number): (message).
     v8::String::Utf8Value filename(message->GetScriptOrigin().ResourceName());
     const char* filename_string = ToCString(filename);
-    int linenum =
-        message->GetLineNumber(isolate->GetCurrentContext()).FromJust();
+    Maybe<int> maybeline = message->GetLineNumber(isolate->GetCurrentContext());
+    int linenum = maybeline.IsJust() ? maybeline.FromJust() : -1;
     printf("%s:%i: %s\n", filename_string, linenum, exception_string);
-    // Print line of source code.
-    v8::String::Utf8Value sourceline(
-        message->GetSourceLine(isolate->GetCurrentContext()).ToLocalChecked());
-    const char* sourceline_string = ToCString(sourceline);
-    printf("%s\n", sourceline_string);
-    // Print wavy underline (GetUnderline is deprecated).
-    int start =
-        message->GetStartColumn(isolate->GetCurrentContext()).FromJust();
-    for (int i = 0; i < start; i++) {
-      printf(" ");
-    }
-    int end = message->GetEndColumn(isolate->GetCurrentContext()).FromJust();
-    for (int i = start; i < end; i++) {
-      printf("^");
+    if (maybeline.IsJust()) {
+      // Print line of source code.
+      v8::String::Utf8Value sourceline(
+          message->GetSourceLine(isolate->GetCurrentContext())
+              .ToLocalChecked());
+      const char* sourceline_string = ToCString(sourceline);
+      printf("%s\n", sourceline_string);
+      // Print wavy underline (GetUnderline is deprecated).
+      int start =
+          message->GetStartColumn(isolate->GetCurrentContext()).FromJust();
+      for (int i = 0; i < start; i++) {
+        printf(" ");
+      }
+      int end = message->GetEndColumn(isolate->GetCurrentContext()).FromJust();
+      for (int i = start; i < end; i++) {
+        printf("^");
+      }
+      printf("\n");
     }
-    printf("\n");
     Local<Value> stack_trace_string;
     if (try_catch->StackTrace(isolate->GetCurrentContext())
             .ToLocal(&stack_trace_string) &&