PING^3 [PATCH] Use the section flag 'o' for __patchable_function_entries

[H.J. Lu]

On Fri, Oct 23, 2020 at 5:41 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Oct 2, 2020 at 6:00 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Thu, Feb 6, 2020 at 6:57 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > >
> > > This commit in GNU binutils 2.35:
> > >
> > > https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=b7d072167715829eed0622616f6ae0182900de3e
> > >
> > > added the section flag 'o' to .section directive:
> > >
> > > .section __patchable_function_entries,"awo",@progbits,foo
> > >
> > > which specifies the symbol name which the section references.  Assembler
> > > creates a unique __patchable_function_entries section with the section,
> > > where foo is defined, as its linked-to section.  Linker keeps a section
> > > if its linked-to section is kept during garbage collection.
> > >
> > > This patch checks assembler support for the section flag 'o' and uses
> > > it to implement __patchable_function_entries section.  Since Solaris may
> > > use GNU assembler with Solairs ld.  Even if GNU assembler supports the
> > > section flag 'o', it doesn't mean that Solairs ld supports it.  This
> > > feature is disabled for Solairs targets.
> > >
> > > gcc/
> > >
> > >         PR middle-end/93195
> > >         PR middle-end/93197
> > >         * configure.ac (HAVE_GAS_SECTION_LINK_ORDER): New.  Define if
> > >         the assembler supports the section flag 'o' for specifying
> > >         section with link-order.
> > >         * dwarf2out.c (output_comdat_type_unit): Pass 0 as flags2
> > >         to targetm.asm_out.named_section.
> > >         * config/sol2.c (solaris_elf_asm_comdat_section): Likewise.
> > >         * output.h (SECTION2_LINK_ORDER): New.
> > >         (switch_to_section): Add an unsigned int argument.
> > >         (default_no_named_section): Likewise.
> > >         (default_elf_asm_named_section): Likewise.
> > >         * target.def (asm_out.named_section): Likewise.
> > >         * targhooks.c (default_print_patchable_function_entry): Pass
> > >         current_function_decl to get_section and SECTION2_LINK_ORDER
> > >         to switch_to_section.
> > >         * varasm.c (default_no_named_section): Add an unsigned int
> > >         argument.
> > >         (default_elf_asm_named_section): Add an unsigned int argument,
> > >         flags2.  Use 'o' flag for SECTION2_LINK_ORDER if assembler
> > >         supports it.
> > >         (switch_to_section): Add an unsigned int argument and pass it
> > >         to targetm.asm_out.named_section.
> > >         (handle_vtv_comdat_section): Pass 0 to
> > >         targetm.asm_out.named_section.
> > >         * config.in: Regenerated.
> > >         * configure: Likewise.
> > >         * doc/tm.texi: Likewise.
> > >
> > > gcc/testsuite/
> > >
> > >         PR middle-end/93195
> > >         * g++.dg/pr93195a.C: New test.
> > >         * g++.dg/pr93195b.C: Likewise.
> > >         * lib/target-supports.exp
> > >         (check_effective_target_o_flag_in_section): New proc.
> >
> > PING
> >
> > https://gcc.gnu.org/pipermail/gcc-patches/2020-February/539963.html
>
> PING.
>

PING.

-- 
H.J.