* [Bug target/94711] [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm
2020-04-22 12:12 [Bug target/94711] New: [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm jakub at gcc dot gnu.org
@ 2020-04-22 12:12 ` jakub at gcc dot gnu.org
2020-04-23 14:38 ` jakub at gcc dot gnu.org
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From: jakub at gcc dot gnu.org @ 2020-04-22 12:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P1
Blocks|94704, 94706, 94707 |
Target|aarch64-*-linux |arm-*-linux
Target Milestone|--- |10.0
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94704
[Bug 94704] [8/9/10 Regression] class with empty base passed incorrectly with
-std=c++17 on s390x/s390
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94706
[Bug 94706] [8/9/10 Regression] class with empty base passed incorrectly with
-std=c++17 on ia64
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94707
[Bug 94707] [8/9/10 Regression] class with empty base passed incorrectly with
-std=c++17 on powerpc64le
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/94711] [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm
2020-04-22 12:12 [Bug target/94711] New: [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm jakub at gcc dot gnu.org
2020-04-22 12:12 ` [Bug target/94711] " jakub at gcc dot gnu.org
@ 2020-04-23 14:38 ` jakub at gcc dot gnu.org
2020-04-23 14:59 ` marxin at gcc dot gnu.org
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From: jakub at gcc dot gnu.org @ 2020-04-23 14:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
Bug 94711 depends on bug 94383, which changed state.
Bug 94383 Summary: [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on aarch64
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94383
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/94711] [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm
2020-04-22 12:12 [Bug target/94711] New: [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm jakub at gcc dot gnu.org
2020-04-22 12:12 ` [Bug target/94711] " jakub at gcc dot gnu.org
2020-04-23 14:38 ` jakub at gcc dot gnu.org
@ 2020-04-23 14:59 ` marxin at gcc dot gnu.org
2020-04-27 8:04 ` jakub at gcc dot gnu.org
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From: marxin at gcc dot gnu.org @ 2020-04-23 14:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2020-04-23
Ever confirmed|0 |1
CC| |marxin at gcc dot gnu.org
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2020-04-22 12:12 [Bug target/94711] New: [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm jakub at gcc dot gnu.org
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2020-04-23 14:59 ` marxin at gcc dot gnu.org
@ 2020-04-27 8:04 ` jakub at gcc dot gnu.org
2020-04-28 14:38 ` cvs-commit at gcc dot gnu.org
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From: jakub at gcc dot gnu.org @ 2020-04-27 8:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, what exactly needs changing on ARM?
>From quick skimming, maybe arm_return_in_memory, very likely
aapcs_vfp_sub_candidate, and maybe arm_needs_doubleword_align.
What about comp_not_to_clear_mask_str_un ?
Note, we'd like to do 10.1-rc1 as early possible and this PR is one of the last
two remaining blockers.
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2020-04-27 8:04 ` jakub at gcc dot gnu.org
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2020-04-28 14:44 ` matmal01 at gcc dot gnu.org
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From: cvs-commit at gcc dot gnu.org @ 2020-04-28 14:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Matthew Malcomson <matmal01@gcc.gnu.org>:
https://gcc.gnu.org/g:a5bff8af0a68d039e1586087639c86d6931c9b81
commit r10-8013-ga5bff8af0a68d039e1586087639c86d6931c9b81
Author: Matthew Malcomson <matthew.malcomson@arm.com>
Date: Tue Apr 28 15:38:43 2020 +0100
[Arm] Account for C++17 artificial field determining Homogeneous Aggregates
In C++14, an empty class deriving from an empty base is not an
aggregate, while in C++17 it is. In order to implement this, GCC adds
an artificial field to such classes.
This artificial field has no mapping to Fundamental Data Types in the
Arm PCS ABI and hence should not count towards determining whether an
object can be passed using the vector registers as per section
"7.1.2 Procedure Calling" in the arm PCS
https://developer.arm.com/docs/ihi0042/latest?_ga=2.60211309.1506853196.1533541889-405231439.1528186050
This patch avoids counting this artificial field in
aapcs_vfp_sub_candidate, and hence calculates whether such objects
should be passed in vector registers in the same manner as C++14 (where
the artificial field does not exist).
Before this change, the test below would pass the arguments to `f` in
general registers. After this change, the test passes the arguments to
`f` using the vector registers.
The new behaviour matches the behaviour of `armclang`, and also matches
the GCC behaviour when run with `-std=gnu++14`.
> gcc -std=gnu++17 -march=armv8-a+simd -mfloat-abi=hard test.cpp
``` test.cpp
struct base {};
struct pair : base
{
float first;
float second;
pair (float f, float s) : first(f), second(s) {}
};
void f (pair);
int main()
{
f({3.14, 666});
return 1;
}
```
We add a `-Wpsabi` warning to catch cases where this fix has changed the
ABI for
some functions. Unfortunately this warning is not emitted twice for
multiple
calls to the same function, but I feel this is not much of a problem and
can be
fixed later if needs be.
(i.e. if `main` called `f` twice in a row we only emit a diagnostic for the
first).
Testing:
Bootstrapped and regression tested on arm-linux.
This change fixes the struct-layout-1 tests Jakub added
https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544204.html
Regression tested on arm-none-eabi.
gcc/ChangeLog:
2020-04-28 Matthew Malcomson <matthew.malcomson@arm.com>
Jakub Jelinek <jakub@redhat.com>
PR target/94711
* config/arm/arm.c (aapcs_vfp_sub_candidate): Account for C++17
empty
base class artificial fields.
(aapcs_vfp_is_call_or_return_candidate): Warn when PCS ABI
decision is different after this fix.
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2020-04-28 14:38 ` cvs-commit at gcc dot gnu.org
@ 2020-04-28 14:44 ` matmal01 at gcc dot gnu.org
2020-04-28 14:45 ` matmal01 at gcc dot gnu.org
2021-11-05 23:18 ` timturnerc at yahoo dot com
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From: matmal01 at gcc dot gnu.org @ 2020-04-28 14:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
--- Comment #3 from Matthew Malcomson <matmal01 at gcc dot gnu.org> ---
This has been fixed by.
https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544625.html
In the email linked above I mentioned another problem using `-mabi=apcs-gnu`.
Since that ABI is obsolete (Kyrylo pointed that out to me) I don't think that
problem should hold up GCC10.
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2020-04-28 14:44 ` matmal01 at gcc dot gnu.org
@ 2020-04-28 14:45 ` matmal01 at gcc dot gnu.org
2021-11-05 23:18 ` timturnerc at yahoo dot com
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From: matmal01 at gcc dot gnu.org @ 2020-04-28 14:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
Matthew Malcomson <matmal01 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #4 from Matthew Malcomson <matmal01 at gcc dot gnu.org> ---
Resolving since the issue with the obsolete ABI is different to this ticket.
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2020-04-22 12:12 [Bug target/94711] New: [8/9/10 Regression] class with empty base passed incorrectly with -std=c++17 on arm jakub at gcc dot gnu.org
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2020-04-28 14:45 ` matmal01 at gcc dot gnu.org
@ 2021-11-05 23:18 ` timturnerc at yahoo dot com
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From: timturnerc at yahoo dot com @ 2021-11-05 23:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711
Tim Turner <timturnerc at yahoo dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |timturnerc at yahoo dot com
--- Comment #5 from Tim Turner <timturnerc at yahoo dot com> ---
[gdb/breakpoints] Handle glibc with debuginfo in
create_exception_master_breakpoint
http://www-look-4.com/computers/huawei-computers/
The test-case nextoverthrow.exp is failing on targets with unstripped libc.
https://komiya-dental.com/category/services/
This is a regression since commit 1940319c0ef "[gdb] Fix internal-error in
process_event_stop_test".
http://www.iu-bloomington.com/category/services/
The problem is that this code in create_exception_master_breakpoint:
...
for (objfile *sepdebug = obj->separate_debug_objfile;
https://waytowhatsnext.com/category/services/
sepdebug != nullptr; sepdebug =
sepdebug->separate_debug_objfile)
if (create_exception_master_breakpoint_hook (sepdebug))
... http://www.wearelondonmade.com/computers/car-computers/
iterates over all the separate debug object files, but fails to handle the
case that obj itself has the debug info we're looking for.
http://www.jopspeech.com/health/nvidia-rtx-2060/
Fix this by using the separate_debug_objfiles () range instead, which does
iterate both over obj and the obj->separate_debug_objfile chain.
http://joerg.li/health/xiaomi/
Tested on x86_64-linux.
http://connstr.net/computers/chargers-tech/
gdb/ChangeLog:
[gdb/breakpoints] Handle glibc with debuginfo in
create_exception_master_breakpoint
http://embermanchester.uk/computers/video-conversation/
The test-case nextoverthrow.exp is failing on targets with unstripped libc.
http://www.slipstone.co.uk/computers/isofix/
This is a regression since commit 1940319c0ef "[gdb] Fix internal-error in
process_event_stop_test".
http://www.logoarts.co.uk/computers/printer-types/
The problem is that this code in create_exception_master_breakpoint:
... http://www.acpirateradio.co.uk/technology/facetime/
for (objfile *sepdebug = obj->separate_debug_objfile;
sepdebug != nullptr; sepdebug =
sepdebug->separate_debug_objfile)
if (create_exception_master_breakpoint_hook (sepdebug))
http://www.compilatori.com/computers/smartphones/
...
iterates over all the separate debug object files, but fails to handle the
case that obj itself has the debug info we're looking for.
https://www.webb-dev.co.uk/category/services/
Fix this by using the separate_debug_objfiles () range instead, which does
iterate both over obj and the obj->separate_debug_objfile chain.
Tested on x86_64-linux.
gdb/ChangeLog:
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