gtags GRTAGS file is too small (only 16Kbytes) in global 6.3.2-6.3.4 on CentOS 7 x86_64

[Anthony Jackson]

First of all, thank you for all of your hard work on GNU global.  My
ability to understand code is greatly enhanced by this excellent tool.

Unfortunately with 6.3.2-6.3.4 on CentOS 7 x86_64, gtags never creates
a GRTAGS file larger than 16K and therefore reverse lookups always
fail (return no output).  On CentOS 6 everything seems to be ok.

OS: CentOS 7 x86_64
Global versions tried: 6.3.2, 6.3.3, 6.3.4

Example run on CentOS 6 x86_64 that works (expected behavior):
$ cd linux-2.6.37
$ gtags
ls -l
...
-rw-r--r--  1 user user   6610944 Feb 18 10:38 GPATH
-rw-r--r--  1 user user 239206400 Feb 18 10:38 GRTAGS
-rw-r--r--  1 user user  98590720 Feb 18 10:37 GTAGS
...
$ global -x get_user_pages
get_user_pages   1549 mm/memory.c      int get_user_pages(struct
task_struct *tsk, struct mm_struct *mm,
get_user_pages    177 mm/nommu.c       int get_user_pages(struct
task_struct *tsk, struct mm_struct *mm,
$ global -xr get_user_pages
get_user_pages   1947 arch/arm/mach-bcmring/dma.c             rc =
get_user_pages(userTask,    /* task */
get_user_pages   2724 arch/cris/arch-v32/drivers/cryptocop.c     err =
get_user_pages(current,
get_user_pages   2741 arch/cris/arch-v32/drivers/cryptocop.c
err = get_user_pages(current,
...

Example run on CentOS 7 (unexpected behavior):
$ cd linux-2.6.37
$ gtags
ls -l
...
-rw-r--r--  1 user user   6610944 Feb 18 11:03 GPATH
-rw-r--r--  1 user user     16384 Feb 18 11:03 GRTAGS
-rw-r--r--  1 user user  98590720 Feb 18 11:04 GTAGS
...
$ global -x get_user_pages
get_user_pages   1549 mm/memory.c      int get_user_pages(struct
task_struct *tsk, struct mm_struct *mm,
get_user_pages    177 mm/nommu.c       int get_user_pages(struct
task_struct *tsk, struct mm_struct *mm,
$ global -xr get_user_pages
<no output!>

Notice that the GRTAGS file is tiny (exactly 16K) as compared to
CentOS 6, and how there is no output from "global -xr get_user_pages".

A similar issue was encountered back in December of 2012, but I didn't
see any resolution on this mailing list.

See http://lists.gnu.org/archive/html/bug-global/2012-12/msg00001.html

Thanks for you consideration.  BTW, I'm highly motivated to solve this
issue.  If you need additional information or tests you need me to run
on our platform, please let me know.

Anthony