[Bug debug/60603] New: .debug_macinfo has wrong line numbers for built-in macros

["tromey at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60603

            Bug ID: 60603
           Summary: .debug_macinfo has wrong line numbers for built-in
                    macros
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tromey at gcc dot gnu.org

The DWARF standard says that macros coming from the command-line
should have line number 0 in the .debug_macinfo data.
I think this ought to apply to built-in macros as well.

Right now gcc gets this wrong and uses a line number of 1.

Here's a test program:

barimba. cat c.c
#define MACRO
int q;


Compile like:

barimba. gcc -DCMDLINE -gstrict-dwarf -g3 -c c.c

Now examine the output:

Contents of the .debug_macinfo section:

 DW_MACINFO_define - lineno : 1 macro : __STDC__ 1
...
 DW_MACINFO_define - lineno : 0 macro : CMDLINE 1
 DW_MACINFO_start_file - lineno: 0 filenum: 1
 DW_MACINFO_start_file - lineno: 0 filenum: 2
 DW_MACINFO_define - lineno : 19 macro : _STDC_PREDEF_H 1
 DW_MACINFO_define - lineno : 30 macro : __STDC_IEC_559__ 1
 DW_MACINFO_define - lineno : 31 macro : __STDC_IEC_559_COMPLEX__ 1
 DW_MACINFO_define - lineno : 35 macro : __STDC_ISO_10646__ 201103L
 DW_MACINFO_define - lineno : 38 macro : __STDC_NO_THREADS__ 1
 DW_MACINFO_end_file
 DW_MACINFO_define - lineno : 1 macro : MACRO 


... so, gcc gets CMDLINE correct but many other things (IMO) wrong.