[llvm] r336072 - Add an entry for rodata constant merge sections to the default

[Sam Clegg via llvm-commits]

Ok, cool thanks.

On Mon, Jul 30, 2018 at 2:49 PM Eric Christopher <echristo at gmail.com> wrote:
>
> Hi Sam,
>
> IIRC I have a couple of follow on patches in the thread, but I can do that if it's causing you problems for sure. Otherwise I've got a fix I'm planning on landing tomorrow at the latest.
>
> -eric
>
> On Thu, Jul 26, 2018 at 3:35 AM Sam Clegg <sbc at google.com> wrote:
>>
>> Should we revert this change and reland with the fix when its ready?
>>
>> Bug is here: https://bugs.llvm.org/show_bug.cgi?id=38165
>> On Tue, Jul 17, 2018 at 2:20 PM Eric Christopher <echristo at gmail.com> wrote:
>> >
>> > Looking. Thanks :)
>> >
>> > On Fri, Jul 13, 2018 at 3:10 PM Sam Clegg <sbc at google.com> wrote:
>> >>
>> >> I believe this change causes previously valid .S files to fail to compile.
>> >>
>> >> The error I'm seeing is on the following line:
>> >> .section    .rodata.cst8,"a", at progbits
>> >>
>> >> This generates:
>> >> amd64.S:728:44: error: expected the entry size
>> >>         .section .rodata.cst8,"a", at progbits
>> >>
>> >> I guess the entry size here was previously implied by the "cst8" name?
>> >>
>> >> The file in question is part of ocaml source:
>> >> https://github.com/ocaml/ocaml/blob/trunk/runtime/amd64.S#L727
>> >> On Sun, Jul 1, 2018 at 5:21 PM Eric Christopher via llvm-commits
>> >> <llvm-commits at lists.llvm.org> wrote:
>> >> >
>> >> > Author: echristo
>> >> > Date: Sun Jul  1 17:16:39 2018
>> >> > New Revision: 336072
>> >> >
>> >> > URL: http://llvm.org/viewvc/llvm-project?rev=336072&view=rev
>> >> > Log:
>> >> > Add an entry for rodata constant merge sections to the default
>> >> > section flags in the ELF assembler. This matches the defaults
>> >> > given in the rest of MC.
>> >> >
>> >> > Fixes PR37997 where we couldn't assemble our own assembly output
>> >> > without warnings.
>> >> >
>> >> > Modified:
>> >> >     llvm/trunk/lib/MC/MCParser/ELFAsmParser.cpp
>> >> >     llvm/trunk/test/MC/ELF/extra-section-flags.s
>> >> >
>> >> > Modified: llvm/trunk/lib/MC/MCParser/ELFAsmParser.cpp
>> >> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/ELFAsmParser.cpp?rev=336072&r1=336071&r2=336072&view=diff
>> >> > ==============================================================================
>> >> > --- llvm/trunk/lib/MC/MCParser/ELFAsmParser.cpp (original)
>> >> > +++ llvm/trunk/lib/MC/MCParser/ELFAsmParser.cpp Sun Jul  1 17:16:39 2018
>> >> > @@ -486,6 +486,9 @@ static bool hasPrefix(StringRef SectionN
>> >> >  // defaults.
>> >> >  static unsigned defaultSectionFlags(StringRef SectionName) {
>> >> >
>> >> > +  if (hasPrefix(SectionName, ".rodata.cst"))
>> >> > +    return ELF::SHF_ALLOC | ELF::SHF_MERGE;
>> >> > +
>> >> >    if (hasPrefix(SectionName, ".rodata.") || SectionName == ".rodata1")
>> >> >      return ELF::SHF_ALLOC;
>> >> >
>> >> >
>> >> > Modified: llvm/trunk/test/MC/ELF/extra-section-flags.s
>> >> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/extra-section-flags.s?rev=336072&r1=336071&r2=336072&view=diff
>> >> > ==============================================================================
>> >> > --- llvm/trunk/test/MC/ELF/extra-section-flags.s (original)
>> >> > +++ llvm/trunk/test/MC/ELF/extra-section-flags.s Sun Jul  1 17:16:39 2018
>> >> > @@ -1,10 +1,12 @@
>> >> >  # RUN: llvm-mc -triple x86_64-unknown-unknown -filetype=obj %s -o /dev/null 2>&1 | FileCheck %s
>> >> > -
>> >> > +
>> >> >  .section .rodata, "ax"
>> >> >  # CHECK: warning: setting incorrect section attributes for .rodata
>> >> >  nop
>> >> >
>> >> >  .section .rodata, "a"
>> >> > -# CHECK-NOT: warning:
>> >> >  nop
>> >> > +.section .rodata.cst4, "aM", at progbits,8
>> >> > +nop
>> >> > +# CHECK-NOT: warning:
>> >> >
>> >> >
>> >> >
>> >> > _______________________________________________
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>> >> > llvm-commits at lists.llvm.org
>> >> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits