[Bug gas/29451] gas-2.39 started adding 0-sized DIEs to functions without .size

[nickc at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29451

Nick Clifton <nickc at redhat dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |nickc at redhat dot com

--- Comment #3 from Nick Clifton <nickc at redhat dot com> ---
(In reply to Sergei Trofimovich from comment #0)

>     <28>   DW_AT_low_pc      : (addr) 0x0
>     <2c>   DW_AT_high_pc     : (addr) 0x0

> Would it be fair to say it's a bug to assign zero size here via DW_AT_low_pc
> / DW_AT_high_pc?

Actually it *is* fair to give them 0 values.  (The values are addresses, not
sizes).  The reason is that the address of the start and end of the
__x86.get_pc_thunk.bx function has not been assigned yet.  (This is an object
file, not a fully linked executable).

If you look at the relocations for the crti.o file you find:

  Relocation section '.rel.debug_info' at offset 0x288 contains 12 entries:
   Offset     Info    Type                Sym. Value  Symbol's Name
   [...]
  00000036  00000901 R_386_32               00000000   __x86.get_pc_thunk.bx
  0000003a  00000901 R_386_32               00000000   __x86.get_pc_thunk.bx

So when this file is linked in with object files and these relocations are
resolved the correct values for the __x86.get_pc_thunk.bx symbol will be
installed into the .debug_info section, and everything should work.

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