From: Luis Machado <luis.machado@arm.com>
To: Carl Love <cel@us.ibm.com>,
gdb-patches@sourceware.org,
Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Cc: Rogerio Alves <rogealve@br.ibm.com>
Subject: Re: [PATCH] PowerPC, add support for printing non-trivial C++ object for the finish command.
Date: Mon, 14 Mar 2022 10:43:35 +0000 [thread overview]
Message-ID: <f64cb1cc-f69f-8cfa-fdc5-c2bed2bccddf@arm.com> (raw)
In-Reply-To: <28ce795ca489f69829207b2a7a535cf7f77f6dd8.camel@us.ibm.com>
On 3/11/22 22:26, Carl Love via Gdb-patches wrote:
>
> GDB maintainers:
>
> The following patch fixes an issue on Powerpc where the function return
> value for a C++ program prints garbage when the function return type is
> a class object. The fix is based on an x86-64 patch for the same
> issue.
>
> The patch has been tested on Power 10 with no regressions. Please let
> me know if this patch is acceptable for mainline. Thanks.
>
> Carl Love
> ---------------------------------------------------
> PowerPC, add support for printing non-trivial C++ object for the finish command.
>
> This patch fixes five testcase failures in gdb/cpp/non-trival-retval.exp.
> The testcases that fail were added by commit:
>
> commit b1718fcdd1d2a5c514f8ee504ba07fb3f42b8608
> Author: Andrew Burgess <aburgess@redhat.com>
> Date: Mon Dec 13 16:56:16 2021 +0000
>
> gdb: on x86-64 non-trivial C++ objects are returned in memory
>
> Fixes PR gdb/28681. It was observed that after using the `finish`
> command an incorrect value was displayed in some cases. Specifically,
> this behaviour was observed on an x86-64 target.
>
> The commit adds new tests for printing the return value of a C++ function.
> The return value of the function is a C++ Class. The current PowerPC code
> is looking for the return value in register r3. The return value is actually
> in memory as described in the commit message for x86-64 above.
>
> The fix for Powerpc is based on the fix in the above commit plus examining
> how x86-64 handles the value in function amd64_return_value in file
> gdb/amd64-tdep.c.
> ---
> gdb/ppc-sysv-tdep.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/gdb/ppc-sysv-tdep.c b/gdb/ppc-sysv-tdep.c
> index 9a3b02f028d..50277e7bdd1 100644
> --- a/gdb/ppc-sysv-tdep.c
> +++ b/gdb/ppc-sysv-tdep.c
> @@ -2035,6 +2035,20 @@ ppc64_sysv_abi_return_value (struct gdbarch *gdbarch, struct value *function,
> return RETURN_VALUE_REGISTER_CONVENTION;
> }
>
> + /* If the object is a non-trivial C++ object the object is in memory. */
> + if (!language_pass_by_reference (valtype).trivially_copyable)
> + {
> + if (readbuf)
> + {
> + ULONGEST addr;
> + int regnum = tdep->ppc_gp0_regnum + 3;
> +
> + regcache_raw_read_unsigned (regcache, regnum, &addr);
> + read_memory (addr, readbuf, TYPE_LENGTH (valtype));
> + }
> + return RETURN_VALUE_ABI_RETURNS_ADDRESS;
> + }
> +
> /* In the ELFv2 ABI, aggregate types of up to 16 bytes are
> returned in registers r3:r4. */
> if (tdep->elf_abi == POWERPC_ELF_V2
Carl,
Just a heads-up that I pushed a new test
(gdb.base/retval-large-struct.exp) that exercises returning a large
struct (> 16 bytes) from a function. You might want to validate that
test on ppc as well, given this particular scenario wasn't being
validated properly in the testsuite.
next prev parent reply other threads:[~2022-03-14 10:43 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-11 22:26 Carl Love
2022-03-13 5:28 ` Joel Brobecker
2022-03-14 10:43 ` Luis Machado [this message]
2022-03-14 13:40 ` Tom Tromey
2022-03-14 13:45 ` Luis Machado
2022-03-14 14:58 ` Ulrich Weigand
[not found] ` <ce6c71356c4a58fcdfb655a6e50c3a24f812e66c.camel@us.ibm.com>
[not found] ` <d9f17525c9a03c20b54015a6a71c36cae50fe4e3.camel@de.ibm.com>
[not found] ` <6ca2276426343756e103995e07ff951d6e26837b.camel@us.ibm.com>
[not found] ` <939797b94ab71f3f7356747d84a1515939cb3dcc.camel@de.ibm.com>
[not found] ` <fccc34c438fda9a35b8a8565e0f5026237e7eab9.camel@us.ibm.com>
[not found] ` <bb5b9b137fc11886964113d4b524526b3c733f4a.camel@us.ibm.com>
[not found] ` <1edb818bd2873a3fa5278f28131089d228a0a4f6.camel@de.ibm.com>
[not found] ` <7c884a865d06890cb325225c65d7a52fdfbd20d2.camel@us.ibm.com>
[not found] ` <846ca96309d2732d3db0e4c323a81105c098fa5f.camel@de.ibm.com>
[not found] ` <5a858dd7b957ecf45cf5b00ffc140a839c8ef023.camel@us.ibm.com>
[not found] ` <b634fecae5e33a3d1a278191c37f306a3b8622f2.camel@de.ibm.com>
[not found] ` <25f2380ced176f58a8e3ea9b70c7e7786988d650.camel@us.ibm.com>
[not found] ` <2b0481466e9ecc33d52c74c3a3b4babb05435f47.camel@de.ibm.com>
[not found] ` <df3b049416ff666e7bd3e3a91e4ea90d34256ea5.camel@us.ibm.com>
[not found] ` <71370ce02bd57827d3b7958772b1594d3591bd16.camel@de.ibm.com>
[not found] ` <ec9dafb1671699b03b28ee4be528711c6988eaa5.camel@us.ibm.com>
[not found] ` <148d8d3efcc8d110119e566027bfd0c65dd02525.camel@de.ibm.com>
[not found] ` <eef62b295e97fc464c22f9d748ff818860137de9.camel@us.ibm.com>
[not found] ` <afd6fa576f479359618b1ee50b08be8932735da8.camel@de.ibm.com>
[not found] ` <cb6b19e9d287d2bae4b72627791f2a00af062c48.camel@us.ibm.com>
[not found] ` <ee7101f86b5c8581905c53347fa603dc23ddc2bd.camel@de.ibm.com>
[not found] ` <8decd662134d57e8caf43960a1cdc47723e2bfe3.camel@us.ibm.com>
[not found] ` <f7cad695cf64540bad8c95cf5fd31691711d0eeb.camel@de.ibm.com>
[not found] ` <79d82ed277308ed5ce312bff398e770ab234390a.camel@us.ibm.com>
[not found] ` <63f21a897f452d81a73fb386cb99110a359ef0b7.camel@de.ibm.com>
[not found] ` <be178bc4f356d7f1937458290cb5883eeee9eee1.camel@us.ibm.com>
[not found] ` <dfd935e9414d3dd2c27d1e877d3718ae7510aa07.camel@de.ibm.com>
[not found] ` <97275f61ef101a12cde8e5a45008ed8e479424eb.camel@us.ibm.com>
[not found] ` <b629440707165f46fb466e48b0c95de3bfa334d2.camel@de.ibm.com>
[not found] ` <191f5826b228a7614c084c9704b086851d418c78.camel@us.ibm.com>
[not found] ` <5405a79ecd6ed34646ad77eed0779063ee222d37.camel@de.ibm.com>
2022-10-06 16:36 ` [PATCH 0/2] PowerPC, fix support for printing the function return value for non-trivial values Carl Love
2022-10-18 18:55 ` [PATCH 0/2 version 2] " Carl Love
2022-10-06 16:37 ` [PATCH 2/2] " Carl Love
2022-10-08 4:36 ` Kevin Buettner
2022-10-12 17:01 ` Carl Love
2022-10-14 2:49 ` Kevin Buettner
2022-10-14 7:36 ` Bruno Larsen
2022-10-14 23:25 ` Carl Love
2022-10-14 23:23 ` Carl Love
2022-10-18 1:06 ` Kevin Buettner
2022-10-18 18:26 ` Carl Love
2022-10-18 18:55 ` [PATCH 2/2 ver 2] " Carl Love
2022-10-31 16:07 ` Carl Love
2022-11-07 14:56 ` Bruno Larsen
2022-11-07 19:53 ` Carl Love
2022-11-07 20:04 ` [PATCH 2/2 ver 3] " Carl Love
2022-11-14 16:47 ` Ulrich Weigand
2022-11-15 7:15 ` Tom de Vries
2022-11-15 10:16 ` Ulrich Weigand
2022-11-15 16:04 ` Carl Love
2022-11-15 16:55 ` Simon Marchi
2022-11-15 23:46 ` Carl Love
2022-11-15 17:24 ` Carl Love
2022-11-15 18:05 ` Ulrich Weigand
2022-11-16 1:01 ` Carl Love
2022-11-16 9:52 ` Ulrich Weigand
2022-11-16 10:12 ` Tom de Vries
2022-11-16 10:20 ` Lancelot SIX
2022-11-16 15:56 ` Carl Love
2022-11-16 20:55 ` [PATCH] Change NULL to nullptr in gdb/infcmd.c and gdb/infrun.c Carl Love
2022-11-16 21:15 ` Simon Marchi
[not found] ` <5a34aaeab59f0099b915d1780c701284a6cf691e.camel@us.ibm.com>
[not found] ` <8aa882863b2f4cef38c22386387c5705bf63c3d5.camel@de.ibm.com>
2022-10-06 16:37 ` [PATCH 1/2] PowerPC, function ppc64_sysv_abi_return_value add missing return value convention Carl Love
2022-10-08 4:20 ` Kevin Buettner
2022-10-14 23:20 ` Carl Love
2022-10-18 18:55 ` [PATCH 1/2 ver 2] " Carl Love
2022-11-07 20:04 ` [PATCH 1/2 ver 3] " Carl Love
2022-11-14 16:45 ` Ulrich Weigand
2022-11-14 19:38 ` Carl Love
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f64cb1cc-f69f-8cfa-fdc5-c2bed2bccddf@arm.com \
--to=luis.machado@arm.com \
--cc=Ulrich.Weigand@de.ibm.com \
--cc=cel@us.ibm.com \
--cc=gdb-patches@sourceware.org \
--cc=rogealve@br.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).