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Re: [PATCH] bfd/elfnn-aarch64.c: Set st_value to zero for undefined symbols
- From: Will Newton <will dot newton at linaro dot org>
- To: Will Newton <will dot newton at linaro dot org>, "binutils at sourceware dot org" <binutils at sourceware dot org>
- Date: Tue, 3 Feb 2015 12:35:12 +0000
- Subject: Re: [PATCH] bfd/elfnn-aarch64.c: Set st_value to zero for undefined symbols
- Authentication-results: sourceware.org; auth=none
- References: <1422535407-4597-1-git-send-email-will dot newton at linaro dot org> <CANu=DmjcY2vEvN-8=8TpWoq1VbxV9EFWG66AU88CQ=CB5=Ki+g at mail dot gmail dot com> <20150203122800 dot GI14796 at bubble dot grove dot modra dot org>
On 3 February 2015 at 12:28, Alan Modra <firstname.lastname@example.org> wrote:
> On Tue, Feb 03, 2015 at 10:36:27AM +0000, Will Newton wrote:
>> On 29 January 2015 at 12:43, Will Newton <email@example.com> wrote:
>> > Unless pointer_equality_needed is set then set st_value to be zero
>> > for undefined symbols. This relates to BZ #16715.
>> > bfd/ChangeLog:
>> > 2015-01-28 Will Newton <firstname.lastname@example.org>
>> > * elfnn-aarch64.c (elfNN_aarch64_finish_dynamic_symbol):
>> > Set st_value to zero for undefined symbols unless
>> > pointer_equality_needed.
>> > ---
>> > bfd/elfnn-aarch64.c | 6 ++++++
>> > 1 file changed, 6 insertions(+)
>> > diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
>> > index 37de7fa..ee718c5 100644
>> > --- a/bfd/elfnn-aarch64.c
>> > +++ b/bfd/elfnn-aarch64.c
>> > @@ -7441,6 +7441,12 @@ elfNN_aarch64_finish_dynamic_symbol (bfd *output_bfd,
>> > comparisons work between an application and shared
>> > library. */
>> > sym->st_shndx = SHN_UNDEF;
>> > + /* If the symbol is weak, we do need to clear the value.
>> > + Otherwise, the PLT entry would provide a definition for
>> > + the symbol even if the symbol wasn't defined anywhere,
>> > + and so the symbol would never be NULL. */
>> > + if (!h->ref_regular_nonweak || !h->pointer_equality_needed)
>> > + sym->st_value = 0;
>> > }
>> > }
> Your description of the patch, changelog, and the new comment and the
> one above it doesn't quite match up with what the code is doing. The
> code is fine, but please fix the comment and changelog.
Yes, I wondered whether to change the comment or not. i copied the
code from the ARM port (which I was the last to modify so it's not
like I can disclaim any responsibility for that!) which is where the
comment came from too. I'll fix the comment in both places.
Toolchain Working Group, Linaro