PING^1: V3 [PATCH 0/2] Switch to a new section if the SECTION_RETAIN bit doesn't match

[H.J. Lu]

On Tue, Dec 8, 2020 at 4:51 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> When SECTION_RETAIN is used, definitions marked with used attribute and
> unmarked definitions are placed in a section with the same name.  Instead
> of issue an error:
>
> [hjl@gnu-cfl-2 gcc]$ /usr/gcc-11.0.0-x32/bin/gcc -S c.c -fdiagnostics-plain-output
> c.c:2:49: error: ‘foo1’ causes a section type conflict with ‘foo2’
> c.c:1:54: note: ‘foo2’ was declared here
> [hjl@gnu-cfl-2 gcc]$
>
> the first patch switches to a new section if the SECTION_RETAIN bit
> doesn't match.  The second optional patch issues a warning:
>
> [hjl@gnu-cfl-2 gcc]$ ./xgcc -B./ -S c.c
> c.c:2:49: warning: ‘foo1’ without ‘used’ attribute and ‘foo2’ with ‘used’ attribute are placed in a section with the same name [-Wattributes]
>     2 | const int __attribute__((section(".data.foo"))) foo1 = 1;
>       |                                                 ^~~~
> c.c:1:54: note: ‘foo2’ was declared here
>     1 | const int __attribute__((used,section(".data.foo"))) foo2 = 2;
>       |
> [hjl@gnu-cfl-2 gcc]$
>
> Changes from V2:
>
> 1. Add (new_section->common.flags & SECTION_NAMED) check since
> SHF_GNU_RETAIN section must be named.
> 2. Move c-c++-common/attr-used-9.c to the fist patch since there are
> no new warnings.
> 3. Check new warnings only for R_flag_in_section target.
>
> H.J. Lu (2):
>   Switch to a new section if the SECTION_RETAIN bit doesn't match
>   Warn used and not used symbols in section with the same name
>
>  gcc/output.h                             |  2 +-
>  gcc/testsuite/c-c++-common/attr-used-5.c | 27 ++++++++++++++
>  gcc/testsuite/c-c++-common/attr-used-6.c | 27 ++++++++++++++
>  gcc/testsuite/c-c++-common/attr-used-7.c |  9 +++++
>  gcc/testsuite/c-c++-common/attr-used-8.c |  9 +++++
>  gcc/testsuite/c-c++-common/attr-used-9.c | 28 +++++++++++++++
>  gcc/varasm.c                             | 46 +++++++++++++++++++++---
>  7 files changed, 143 insertions(+), 5 deletions(-)
>  create mode 100644 gcc/testsuite/c-c++-common/attr-used-5.c
>  create mode 100644 gcc/testsuite/c-c++-common/attr-used-6.c
>  create mode 100644 gcc/testsuite/c-c++-common/attr-used-7.c
>  create mode 100644 gcc/testsuite/c-c++-common/attr-used-8.c
>  create mode 100644 gcc/testsuite/c-c++-common/attr-used-9.c
>

PING.

-- 
H.J.