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Re: [gofrontend-dev] [PATCH 5/9] Gccgo port to s390[x] -- part I


On Fri, Oct 03, 2014 at 06:25:55PM -0700, Ian Lance Taylor wrote:
> On Tue, Sep 9, 2014 at 5:56 AM, Dominik Vogt <vogt@linux.vnet.ibm.com> wrote:
> >         * libgo/go/debug/elf/file.go (applyRelocationsAMD64):
> >         Fix the calculation of some relocations; do not assume that the symbol
> >         value is always zero.
> 
> The code checks that it is using only STT_SECTION symbols.  An
> STT_SECTION symbol in an object file can be reasonably expected to
> have a value of zero.  Since in practice this only applies to debug
> sections, I doubt it would work at all if the STT_SECTION symbol had a
> non-zero value and that value were added in.  So I'm not convinced
> that this patch is necessary.

Well, my x86 knowledge is limited, and the patch is neither
required for the s390[x] port nor (at the moment) for x64_64.

On s390[x] the symbol value of a section symbol is definitely not
zero.  In the amd64 Abi I cannot see anything that would enforce
that sym.Value is 0 for section symbols, although it seems to be
the case on the tested x86_64 system.  In any case, if the patch
is not committed, we should at least add a comment that the symbol
value is omitted from the calculation because it is assumed to be
zero.

Ciao

Dominik ^_^  ^_^

-- 

Dominik Vogt
IBM Germany


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