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From: "vries at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug exp/26875] Incorrect value printed for address of first element of zero-length array
Date: Fri, 20 Nov 2020 22:16:22 +0000 [thread overview]
Message-ID: <bug-26875-4717-avlXXYn5AJ@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-26875-4717@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=26875
--- Comment #11 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Simon Marchi from comment #7)
> I am not able to reproduce. In my version of the compiled test case, both
> bounds are const:
>
> (top-gdb) p type->bounds ()->low.kind ()
> $4 = PROP_CONST
> (top-gdb) p type->bounds ()->high.kind ()
> $5 = PROP_CONST
>
> What compiler do you use to build the test case?
Gcc 7.5.0
> In my version, this is the
> DIE that corresponds to the type of the zero-length field:
>
> 0x00000076: DW_TAG_array_type
> DW_AT_type [DW_FORM_ref4] (0x00000044 "int")
> DW_AT_sibling [DW_FORM_ref4] (0x00000086)
>
> 0x0000007f: DW_TAG_subrange_type
> DW_AT_type [DW_FORM_ref4] (0x0000003d "long unsigned
> int")
> DW_AT_count [DW_FORM_data1] (0x00)
>
I get:
...
<1><13a>: Abbrev Number: 2 (DW_TAG_array_type)
<13b> DW_AT_type : <0x10b>
<13f> DW_AT_sibling : <0x149>
<2><143>: Abbrev Number: 9 (DW_TAG_subrange_type)
<144> DW_AT_type : <0x104>
...
without DW_AT_count.
The DW_AT_count is added at gcc-9, and using that the test-cases passes for me.
> So I presume GDB translates that to two constant bounds with value 0. What
> does it look like in yours?
>
> I stumbled on a similar problem and filed this bug here, they are likely
> related:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=26901
>
> I have this patch series in the pipeline that I made to address 26901:
>
> https://review.lttng.org/c/binutils-gdb/+/4399/4
>
Ah, thanks for the pointer, I'll take a look.
> If/when I am able to reproduce this (26875) bug, I can check if that helps
> with it too.
That would be great.
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next prev parent reply other threads:[~2020-11-20 22:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 9:32 [Bug exp/26875] New: " vries at gcc dot gnu.org
2020-11-13 10:33 ` [Bug exp/26875] " vries at gcc dot gnu.org
2020-11-13 10:53 ` vries at gcc dot gnu.org
2020-11-13 14:47 ` vries at gcc dot gnu.org
2020-11-13 16:52 ` vries at gcc dot gnu.org
2020-11-14 11:45 ` vries at gcc dot gnu.org
2020-11-14 12:04 ` vries at gcc dot gnu.org
2020-11-20 18:00 ` simark at simark dot ca
2020-11-20 18:03 ` simark at simark dot ca
2020-11-20 18:07 ` simark at simark dot ca
2020-11-20 18:17 ` simark at simark dot ca
2020-11-20 22:16 ` vries at gcc dot gnu.org [this message]
2020-11-20 22:25 ` simark at simark dot ca
2020-11-23 16:25 ` simark at simark dot ca
2020-12-09 18:53 ` cvs-commit at gcc dot gnu.org
2020-12-09 21:34 ` cvs-commit at gcc dot gnu.org
2020-12-09 22:11 ` simark at simark dot ca
2021-10-13 14:22 ` vries at gcc dot gnu.org
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