From: "mark at klomp dot org" <sourceware-bugzilla@sourceware.org>
To: elfutils-devel@sourceware.org
Subject: [Bug libdw/27805] libdwfl: Unable to extract source line information for RISC-V binary
Date: Wed, 05 May 2021 14:36:29 +0000 [thread overview]
Message-ID: <bug-27805-10460-Um6SMXwuUm@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-27805-10460@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=27805
Mark Wielaard <mark at klomp dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mark at klomp dot org
--- Comment #2 from Mark Wielaard <mark at klomp dot org> ---
(In reply to Jim Wilson from comment #1)
> Using readelf -wr to look at the debug_aranges section, I see entries like
>
> Length: 44
> Version: 2
> Offset into .debug_info: 0x987
> Pointer Size: 4
> Segment Size: 0
>
> Address Length
> 00000000 00000000
> 20400132 00000002
> 20400134 0000003a
> 00000000 00000000
>
> An address/length entry of 0/0 is supposed to mark the end of the list, but
> here we have one at the beginning. This is confusing elfutils which is
> trying to move byte by byte through the aranges section.
> libdw/dwarf_aranges.c has
> /* Two zero values mark the end. */
> if (range_address == 0 && range_length == 0)
> break;
> and then assumes that the next entry is immediately following, which it
> isn't, and it ends up reading garbage. binutils seems to be using the
> length field to find the last entry. And readelf is ignoring the 0/0 end of
> list rule so that we can see the invalid entries.
>
> There are a lot of aranges that have 0/0 entries not at the end of the list.
Any idea where they come from?
And what does it look like when using -gdwarf-5?
You should get a .debug_rnglists section in that case which has explicit end of
list markers (before DWARF5 the double zero addresses are interpreted as end of
list).
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next prev parent reply other threads:[~2021-05-05 14:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-30 12:31 [Bug libdw/27805] New: " n2knqf5ogu at bsogq dot anonbox.net
2021-05-01 20:48 ` [Bug libdw/27805] " wilson at gcc dot gnu.org
2021-05-05 14:36 ` mark at klomp dot org [this message]
2021-05-05 15:42 ` wilson at gcc dot gnu.org
2021-05-05 15:59 ` wilson at gcc dot gnu.org
2021-05-06 9:43 ` mark at klomp dot org
2021-07-28 11:55 ` n2knqf5ogu at bsogq dot anonbox.net
2023-10-06 12:10 ` mark at klomp dot org
2023-10-09 16:15 ` mark at klomp dot org
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