Hi, 
This is the second version of the patch based on the previous discussion.
In this new version, the major changes are:

1. The name of the option is changed to -flarge-source-files;
2. Add a hint to use this new option “-flarge-source-files” in the routine “get_visual_column”;
3. Documentation for this new option;
4. Update the testing case location-overflow-test-1.c to include the new hint.

Please take a look at this new patch and let me know any new comment.

thanks.

Qing.

gcc/ChangeLog:

2020-04-22  qing zhao  <qing.zhao@oracle.com>

	PR c/94230
	* common.opt: Add -flarge-source-files.
	* doc/invoke.texi: Document it.
	* toplev.c (process_options): set line_table->default_range_bits
	to 0 when flag_large_source_files is true.


gcc/c-family/ChangeLog:

2020-04-22  qing zhao  <qing.zhao@oracle.com>

	PR c/94230
	* c-indentation.c (get_visual_column): Add a hint to use the new
	-flarge-source-files option.

gcc/testsuite/ChangeLog:

2020-04-22  qing zhao  <qing.zhao@oracle.com>

	PR c/94230
	* gcc.dg/plugin/location-overflow-test-1.c (fn_1): New message to 
	provide hint to use the new -flarge-source-files option.