Bug 31439 - error: undefined reference to '__dwarf_get_units_internal'
Summary: error: undefined reference to '__dwarf_get_units_internal'
Status: RESOLVED FIXED
Alias: None
Product: elfutils
Classification: Unclassified
Component: general (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-03-02 03:58 UTC by rudi
Modified: 2024-03-02 23:53 UTC (History)
2 users (show)

See Also:
Host: x86_64
Target: x86_64
Build:
Last reconfirmed:


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Description rudi 2024-03-02 03:58:02 UTC
When cross-compiling 0.191 as target if fails linking with

  CCLD     readelf
readelf.o:readelf.c:function str_offsets_base_off:(.text+0x804e): error: undefined reference to '__dwarf_get_units_internal'
collect2: error: ld returned 1 exit status

Full output:
Comment 1 Mark Wielaard 2024-03-02 14:09:42 UTC
I don't fully understand how you are building, and I cannot replicate, but it seems something goes wrong with readelf.c using the libdwP.h "internals" header. Does the following patch help?

diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index 8b2f06fa5937..c1c84ed3567d 100644
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -1153,8 +1153,7 @@ str_offsets_base_off (Dwarf *dbg, Dwarf_CU *cu)
   if (cu == NULL && dbg != NULL)
     {
       Dwarf_CU *first_cu;
-      if (INTUSE(dwarf_get_units) (dbg, NULL, &first_cu,
-				   NULL, NULL, NULL, NULL) == 0)
+      if (dwarf_get_units (dbg, NULL, &first_cu, NULL, NULL, NULL, NULL) == 0)
 	cu = first_cu;
     }
Comment 2 rudi 2024-03-02 23:04:10 UTC
(In reply to Mark Wielaard from comment #1)
> I don't fully understand how you are building, and I cannot replicate, but
> it seems something goes wrong with readelf.c using the libdwP.h "internals"
> header. Does the following patch help?
> 
> diff --git a/libdw/libdwP.h b/libdw/libdwP.h
> index 8b2f06fa5937..c1c84ed3567d 100644
> --- a/libdw/libdwP.h
> +++ b/libdw/libdwP.h
> @@ -1153,8 +1153,7 @@ str_offsets_base_off (Dwarf *dbg, Dwarf_CU *cu)
>    if (cu == NULL && dbg != NULL)
>      {
>        Dwarf_CU *first_cu;
> -      if (INTUSE(dwarf_get_units) (dbg, NULL, &first_cu,
> -				   NULL, NULL, NULL, NULL) == 0)
> +      if (dwarf_get_units (dbg, NULL, &first_cu, NULL, NULL, NULL, NULL) ==
> 0)
>  	cu = first_cu;
>      }

Hi mark, sorry for not sharing more yesterday, somehow I locked my account out on sourceware…. But I can confirm your patch does fix the build.
Comment 3 Mark Wielaard 2024-03-02 23:53:29 UTC
Thanks for testing. I don't know why I am unable to replicate or why none of our buildbots caught this. But it makes sense that an INTUSE used in readelf might cause issues.

Fixed by:

commit 7cf4586e5b429c0fa74d3ae73f49e6cda6660e93
Author: Mark Wielaard <mark@klomp.org>
Date:   Sun Mar 3 00:45:34 2024 +0100

    libdw: Don't use INTUSE in libdwP.h str_offsets_base_off
    
    readelf.c cheats and include libdwP.h, which is an internal only
    header of libdw. It really shouldn't do that, but there are some
    internals that readelf currently needs. The str_offsets_base_off
    function used by readelf uses INTUSE when calling dwarf_get_units.
    This is a micro optimization useful inside libdw so a public
    function can be called directly, skipping a PLT call. This can
    cause issues linking readelf since it might not be able to call
    the internal function, since readelf.c isn't part of libdw itself.
    Just drop the INTUSE.
    
            * libdw/libdwP.h (str_offsets_base_off): Don't use INTUSE
            when calling dwarf_get_units.
    
    Signed-off-by: Mark Wielaard <mark@klomp.org>