Re: [PATCH] PR rtl-optimization/32219: optimizer causees wrong code in pic/hidden/weak symbol checking

["H.J. Lu" <hjl.tools@gmail.com>]

On Thu, Feb 19, 2015 at 1:07 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Feb 19, 2015 at 1:04 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Mon, Feb 16, 2015 at 5:30 PM, Richard Henderson <rth@redhat.com> wrote:
>>
>>>>>> 2015-02-12  H.J. Lu  <hongjiu.lu@intel.com>
>>>>>>             Richard Henderson  <rth@redhat.com>
>>>>>>
>>>>>>         PR rtl/32219
>>>>>>         * cgraphunit.c (cgraph_node::finalize_function): Set definition
>>>>>>         before notice_global_symbol.
>>>>>>         (varpool_node::finalize_decl): Likewise.
>>>>>>         * varasm.c (default_binds_local_p_2): Rename from
>>>>>>         default_binds_local_p_1, add weak_dominate argument.  Use direct
>>>>>>         returns instead of assigning to local variable.  Unify varpool and
>>>>>>         cgraph paths via symtab_node.  Reject undef weak variables before
>>>>>>         testing visibility.  Reorder tests for simplicity.
>>>>>>         (default_binds_local_p): Use default_binds_local_p_2.
>>>>>>         (default_binds_local_p_1): Likewise.
>>>>>>         (decl_binds_to_current_def_p): Unify varpool and cgraph paths
>>>>>>         via symtab_node.
>>>>>>         (default_elf_asm_output_external): Emit visibility when specified.
>>>>>
>>>>> It looks like this patch broke alphaev68-linux-gnu [1]. There are many
>>>>> failures of the type:
>>>>>
>>>>> /tmp/cck7V7MR.o: In function
>>>>> `__static_initialization_and_destruction_0(int, int)':^M
>>>>> (.text+0x3ac): relocation truncated to fit: GPRELHIGH against symbol
>>>>> `std::__cxx11::basic_string<char, std::char_traits<char>,
>>>>> std::allocator<char> >::~basic_string()@@GLIBCXX_3.4.21' defined in
>>>>> .text section in
>>>>> /space/uros/gcc-build/alphaev68-unknown-linux-gnu/./libstdc++-v3/src/.libs/libstdc++.so^M
>>>>> /space/homedirs/uros/local/bin/ld: /tmp/cck7V7MR.o: gp-relative
>>>>> relocation against dynamic symbol
>>>>
>>>> It could be related to:
>>>>
>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65064
>>>>
>>>> Before this bug fix, all common symbols don't bind locally,
>>>> which is one of PR 32219 bugs.  After this fix, common
>>>> symbols bind locally.  It may cause problems on targets with
>>>> small data sections and common symbols aren't in small
>>>> data section:
>>>
>>> This is a destructor, and so obviously not a common symbol.
>>>
>>> I'll have a look.
>>
>> The attached patch fixes all alpha-linux-gnu failures.
>>
>> 2015-02-19  Uros Bizjak  <ubizjak@gmail.com>
>>
>>     * config/alpha/alpha.c (alpha_in_small_data_p): Reject common symbols.
>>
>> Patch was bootstrapped and regression tested on alphaev68-linux-gnu.
>>
>> OK for mainline?
>>
>
> You may want to use something like this:
>
> https://gcc.gnu.org/ml/gcc-patches/2015-02/msg01105.html
>

See:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65064

for why.

-- 
H.J.