[Bug preprocessor/108900] New: [libcpp] cpp gives wrong line number information

["libin.dang at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108900

            Bug ID: 108900
           Summary: [libcpp] cpp gives wrong line number information
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: libin.dang at gmail dot com
  Target Milestone: ---

Created attachment 54514
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54514&action=edit
test case

Reproduce:

$ /home/wrsadmin/works/gcc/b0/gcc/cpp -B /home/wrsadmin/works/gcc/b0/gcc main.c
-o main.i

$ tail main.i
header3 begins
header3 begins
# 1 "header2.h" 1
# 327614 "header3.h" 2
header3 ends
# 4 "header1.h" 2
# 1 "header4.h" 1
# 5 "header1.h" 2
header1 ends
# 2 "main.c" 2

$ cat -n header3.h | tail
327606  header3 begins
327607  header3 begins
327608  header3 begins
327609  header3 begins
327610  header3 begins
327611  header3 begins
327612  header3 begins
327613  header3 begins
327614  #include "header2.h"
327615  header3 ends


The line number information for `header3 ends' is wrong.

BTW, this issue is very sensitive to the input files, for example, if we add
another line `header3 begins' above the `#include "header2.h"' in header3.h, we
will get the correct result:

$ cat -n header3.h | tail
327607  header3 begins
327608  header3 begins
327609  header3 begins
327610  header3 begins
327611  header3 begins
327612  header3 begins
327613  header3 begins
327614  header3 begins
327615  #include "header2.h"
327616  header3 ends

$ tail main.i
header3 begins
header3 begins
# 1 "header2.h" 1
# 327616 "header3.h" 2
header3 ends
# 4 "header1.h" 2
# 1 "header4.h" 1
# 5 "header1.h" 2
header1 ends
# 2 "main.c" 2