Re: [PATCH 4/8] section-select: Completely rebuild matches

[Michael Matz <matz@suse.de>]

Hello,

On Mon, 28 Nov 2022, Alan Modra wrote:

> On Fri, Nov 25, 2022 at 04:55:12PM +0000, Michael Matz via Binutils wrote:
> > this resets all section matches before updating for newly created
> > sections (i.e. completely rebuilds the matches).  This fixes powerpc
> > "TOC opt" tests that shows a difference in section order: originally
> > .got of "linker stubs" comes before .toc (both placed into the same
> > .got output section due to ".got {*(.got .toc)}".  But .got of linker
> > stubs is created later, and in the second run of resolve_wilds is
> > appended to the list, hence is then coming after .toc (which was added
> > already in the earlier resolve_wilds run).  So order swapped ->
> > test fails.
> 
> That's a problem.  The got header is created in the .got of "linker
> stubs", and code setting the value of .TOC. assumes that the header
> will be located first in the .got output section.  This ties in with
> where ld.so expects to find the header too.

I see.  But then why is the testcase (and linker script?) not using

  .got { *(.got) *(.toc) }

?  The way it's written right now means "for each file, first its .got 
then its .toc, intermixed", i.e. file1.got, file1.toc, file2.got, 
file2.toc ...  And it seems a bit fuzzy to speak about "files" for the 
artificial generated pseudo files like "linker stubs".

(Just to be clear: rebuilding all matches also solves this problem)


Ciao,
Michael.