[d8] Make exception reporting more resilient.

src/d8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 // Defined when linking against shared lib on Windows.
 #if defined(USING_V8_SHARED) && !defined(V8_SHARED)
 #define V8_SHARED
 #endif
 
@@ skipping 907 matching lines @@
   const char* exception_string = ToCString(exception);
   Local<Message> message = try_catch->Message();
   if (message.IsEmpty()) {
     // V8 didn't provide any extra information about this error; just
     // print the exception.
     printf("%s\n", exception_string);
   } else {
     // 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(" ");
+    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");
     }
-    int end = message->GetEndColumn(isolate->GetCurrentContext()).FromJust();
-    for (int i = start; i < end; i++) {
-      printf("^");
-    }
-    printf("\n");
     Local<Value> stack_trace_string;
     if (try_catch->StackTrace(isolate->GetCurrentContext())
             .ToLocal(&stack_trace_string) &&
         stack_trace_string->IsString()) {
       v8::String::Utf8Value stack_trace(
           Local<String>::Cast(stack_trace_string));
       printf("%s\n", ToCString(stack_trace));
     }
   }
   printf("\n");
@@ skipping 1590 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif