Improve exception printing for debug

src/isolate.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.
 
 #include "src/isolate.h"
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
@@ skipping 1054 matching lines @@
 
 Object* Isolate::Throw(Object* exception, MessageLocation* location) {
   DCHECK(!has_pending_exception());
 
   HandleScope scope(this);
   Handle<Object> exception_handle(exception, this);
 
   if (FLAG_print_all_exceptions) {
     printf("=========================================================\n");
     printf("Exception thrown:\n");
+    if (location) {
+      Handle<Script> script = location->script();
+      Handle<Object> name = Script::GetNameOrSourceURL(script);
+      printf("at ");
+      if (name->IsString() && String::cast(*name)->length() > 0)
+        String::cast(*name)->PrintOn(stdout);
+      else
+        printf("<anonymous>");
+#ifdef DEBUG
+      if (AllowHeapAllocation::IsAllowed()) {

[titzer, 2016/10/26 15:52:47]

Maybe add a comment that GetColumnNumber() allocates?

[Clemens Hammacher, 2016/10/26 16:15:41]

Done.

+#else
+      if (false) {
+#endif
+        printf("%d:%d - %d:%d\n",
+               Script::GetLineNumber(script, location->start_pos()) + 1,
+               Script::GetColumnNumber(script, location->start_pos()),
+               Script::GetLineNumber(script, location->end_pos()) + 1,
+               Script::GetColumnNumber(script, location->end_pos()));
+      } else {
+        printf("line %d\n", script->GetLineNumber(location->start_pos()) + 1);
+      }
+    }
     exception->Print();
     printf("Stack Trace:\n");
     PrintStack(stdout);
     printf("=========================================================\n");
   }
 
   // Determine whether a message needs to be created for the given exception
   // depending on the following criteria:
   // 1) External v8::TryCatch missing: Always create a message because any
   //    JavaScript handler for a finally-block might re-throw to top-level.
@@ skipping 2379 matching lines @@
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8