[gold commit] (PR gold/16992) Fix --dynamic-list so that symbols not in the list are still exported

[Cary Coutant <ccoutant at google dot com>]

In PR 13577, the complaint was that -Bsymbolic was overriding the binding
behavior for symbols listed in the --dynamic-list by setting the DT_SYMBOLIC
tag in the dynamic table. In reading the Gnu ld manual, I decided that
--dynamic-list should be mutually exclusive of -Bsymbolic, and modified
gold so that --dynamic-list would treat symbols listed as preemptible,
and all other symbols as internally bound. I was wrong.

PR 16992 shows that with --dynamic-list (and not -Bsymbolic), a symbol
not listed in the dynamic list is being internally bound within the
shared library, but because it's still in the dynamic symbol table, we
expose it to a COPY relocation, and things go really bad from there.

(I can reproduce the same failure, simply by turning on -Bsymbolic-functions
with the Gnu linker. Even though the symbol is bound internally, it's
still exported to the dynamic symbol table, and is exposed to a COPY
relocation.)

I've backed out part of the fix for PR 13577, and -Bsymbolic (or
-Bsymbolic-functions) can now be used with --dynamic-list, but if the
two are used together, we do not set DT_SYMBOLIC or DF_SYMBOLIC
(this matches Gnu ld behavior). We now treat symbols listed in the
dynamic list as premptible, but we do not automatically treat symbols
not listed there as non-premptible.

-cary


2015-02-16  Cary Coutant  <ccoutant@google.com>

gold/
        PR gold/13577
        PR gold/16992
        * layout.cc (Layout::finish_dynamic_section): Don't set DT_SYMBOLIC or
        DF_SYMBOLIC if --dynamic-list option is used.
        * options.cc (General_options::finalize): --dynamic-list is not
        mutually exclusive with -Bsymbolic.
        * symtab.h (Symbol::is_preemptible): Don't exclude dynamic symbols not
        listed in --dynamic-list.
        * testsuite/Makefile.am (dynamic_list_lib2.so): Add
        -Bsymbolic-functions.
        * testsuite/Makefile.in: Regenerate.

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