Re: Warning when using separate debug info file

[Eli Zaretskii <eliz@gnu.org>]

> From: Tom Tromey <tom@tromey.com>
> Cc: Tom Tromey <tom@tromey.com>,  lrn1986@gmail.com,  gdb-patches@sourceware.org
> Date: Thu, 25 Apr 2019 07:46:23 -0600
> 
> I tried and it doesn't give a warning.

That's what I thought.  So somehow this is specific to PE executables.
I'm at a loss as to why that would be a factor.

> Eli> The place where this happens, addr_info_make_relative, maps addresses
> Eli> to BFD addresses, and I wonder why .gnu_debuglink appears in the array
> Eli> of sections the GDB looks up in the separate debug file.  Any ideas
> Eli> why this happens?
> 
> Try looking at the section headers:
> 
>     $ objdump -h -j .gnu_debuglink q
> 
>     q:     file format elf64-x86-64
> 
>     Sections:
>     Idx Name          Size      VMA               LMA               File off  Algn
>      25 .gnu_debuglink 0000000c  0000000000000000  0000000000000000  000013cc  2**2
>                       CONTENTS, READONLY
> 
> I don't recall which but probably the section is either loadable or
> allocatable in your situation.

Both, it looks:

  objdump -h -j .gnu_debuglink hello.exe

  hello.exe:     file format pei-i386

  Sections:
  Idx Name          Size      VMA       LMA       File off  Algn
   14 .gnu_debuglink 00000014  00416000  00416000  0000c600  2**2
		    CONTENTS, ALLOC, LOAD, READONLY, DATA

But the question is why GDB looks for this section in the hello.debug
file, not in hello.exe.  That's what the warning emitted by GDB is
about:

  (gdb) file ./hello.exe
  Reading symbols from ./hello.exe...Reading symbols from D:\usr\eli\data\hello.debug...warning: section .gnu_debuglink not found in D:\usr\eli\data\hello.debug

What do you get with the above objdump command on the separate debug
file?  I get an error message:

  objdump -h -j .gnu_debuglink hello.debug

  hello.debug:     file format pei-i386

  Sections:
  Idx Name          Size      VMA       LMA       File off  Algn
  objdump: section '.gnu_debuglink' mentioned in a -j option, but not found in any input file

Thanks.