[PATCH] D30080: MC/COFF: Do not emit forward associative section referenceds.

[Rui Ueyama via llvm-commits]

On Fri, Feb 17, 2017 at 10:06 AM, Rafael Avila de Espindola <
rafael.espindola at gmail.com> wrote:

> > +// Write the section header.
> > +void WinCOFFObjectWriter::writeSectionHeaders() {
> > +  // Section numbers must be monotonically increasing in the section
> > +  // header, but our Sections array is not sorted by section number,
> > +  // so make a copy of Sections and sort it.
> > +  std::vector<COFFSection *> Arr;
> > +  for (auto &Section : Sections)
> > +    Arr.push_back(Section.get());
>
> Can you say just  std::vector<COFFSection *> Arr = Sections; ?
>

Sections is a std::vector<std::unique_ptr<COFFSection>>, so you can't.

>  void WinCOFFObjectWriter::assignSectionNumbers() {
> >    size_t I = 1;
> > -  for (const auto &Section : Sections) {
> > -    Section->Number = I;
> > -    Section->Symbol->Data.SectionNumber = I;
> > -    Section->Symbol->Aux[0].Aux.SectionDefinition.Number = I;
> > +  auto Assign = [&](COFFSection &Section) {
> > +    Section.Number = I;
> > +    Section.Symbol->Data.SectionNumber = I;
> > +    Section.Symbol->Aux[0].Aux.SectionDefinition.Number = I;
> >      ++I;
> > -  }
> > +  };
> > +
> > +  // Although it is not explicitly requested by the Microsoft COFF spec,
> > +  // we should avoid emitting forward associative section references,
> > +  // because MSVC link.exe as of 2017 cannot handle that.
> > +  for (const std::unique_ptr<COFFSection> &Section : Sections)
> > +    if (!isAssociative(*Section))
> > +      Assign(*Section);
> > +  for (const std::unique_ptr<COFFSection> &Section : Sections)
> > +    if (isAssociative(*Section))
> > +      Assign(*Section);
> >  }
>
> An associative section cannot refer to another?
>

They can't.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170217/ed246141/attachment.html>