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

[Uros Bizjak <ubizjak at gmail dot com>]

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?

Uros.

Index: config/alpha/alpha.c
===================================================================
--- config/alpha/alpha.c        (revision 220806)
+++ config/alpha/alpha.c        (working copy)
@@ -835,6 +835,10 @@ alpha_in_small_data_p (const_tree exp)
   if (TREE_CODE (exp) == FUNCTION_DECL)
     return false;

+  /* COMMON symbols are never small data.  */
+  if (TREE_CODE (exp) == VAR_DECL && DECL_COMMON (exp))
+    return false;
+
   if (TREE_CODE (exp) == VAR_DECL && DECL_SECTION_NAME (exp))
     {
       const char *section = DECL_SECTION_NAME (exp);