On 05/27/14 23:20, Jan Hubicka wrote:
here we have decl and its local alias:
(gdb) p debug_tree (sect->named.decl)
<var_decl 70f7d060 _ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si
type<array_type 70dd8840
type<pointer_type 700f5840 __vtbl_ptr_type type<function_type 700f57e0>
unsigned SI
size<integer_cst 70006498 constant 32>
unit size<integer_cst 700064b0 constant 4>
align 32 symtab 45 alias set 3 canonical type 700f5840
pointer_to_this<pointer_type 700f5900>>
BLK
size<integer_cst 708002d0 constant 320>
unit size<integer_cst 708000d8 constant 40>
align 32 symtab 0 alias set 3 canonical type 70dd8840
domain<integer_type 701a78a0 type<integer_type 7001d000 sizetype>
type_6 SI size<integer_cst 70006498 32> unit size<integer_cst
700064b0 4>
align 32 symtab 0 alias set -1 canonical type 701a78a0 precision 32
min<integer_cst 700064c8 0> max<integer_cst 701a5b88 9>>
pointer_to_this<pointer_type 71272d80>>
readonly addressable used public static tree_1 tree_5 tree_6 ignored weak
in_system_header virtual decl_5 SI file
/home/jh/trunk/c/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/fstream line 444 col 11
size<integer_cst 708002d0 320> unit size<integer_cst 708000d8 40>
user align 32 context<record_type 701eb000 basic_ifstream>
initial<constructor 70f63680>
(mem/u/c:SI (symbol_ref/i:SI ("_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si")
[flags 0x82]<var_decl 70f7d060 _ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si>) [3
_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si+0 S40 A32])>
$6 = 10
(gdb) p debug_tree (decl)
<var_decl 714174e0
_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si.localalias.69
type<array_type 70dd8840
type<pointer_type 700f5840 __vtbl_ptr_type type<function_type 700f57e0>
unsigned SI
size<integer_cst 70006498 constant 32>
unit size<integer_cst 700064b0 constant 4>
align 32 symtab 45 alias set 3 canonical type 700f5840
pointer_to_this<pointer_type 700f5900>>
BLK
size<integer_cst 708002d0 constant 320>
unit size<integer_cst 708000d8 constant 40>
align 32 symtab 0 alias set 3 canonical type 70dd8840
domain<integer_type 701a78a0 type<integer_type 7001d000 sizetype>
type_6 SI size<integer_cst 70006498 32> unit size<integer_cst
700064b0 4>
align 32 symtab 0 alias set -1 canonical type 701a78a0 precision 32
min<integer_cst 700064c8 0> max<integer_cst 701a5b88 9>>
pointer_to_this<pointer_type 71272d80>>
readonly addressable used static tree_1 tree_5 tree_6 ignored in_system_header decl_5
SI file /home/jh/trunk/c/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/fstream line 444 col
11 size<integer_cst 708002d0 320> unit size<integer_cst 708000d8 40>
user align 32 context<record_type 701eb000 basic_ifstream>
>
$7 = 10
Perhaps get_vairable_section should look for alias target, since that is the
decl really deciding on the section? Richard?
This is patch that makes get_variable_section to look through the aliases
Index: varasm.c
===================================================================
--- varasm.c (revision 210914)
+++ varasm.c (working copy)
@@ -1083,6 +1083,9 @@
{
addr_space_t as = ADDR_SPACE_GENERIC;
int reloc;
+ symtab_node *snode = symtab_get_node (decl);
+ if (snode)
+ decl = symtab_alias_ultimate_target (snode)->decl;
if (TREE_TYPE (decl) != error_mark_node)
as = TYPE_ADDR_SPACE (TREE_TYPE (decl));
For AIX it makes the bug go away and I eventually get:
/tmp//ccyAATFr.s: line 30042: 1252-001
_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si.localalias.69 is defined
already.
/tmp//ccyAATFr.s: line 30125: 1252-001
_ZTCSt14basic_ofstreamIcSt11char_traitsIcEE0_So.localalias.71 is defined
already.
/tmp//ccyAATFr.s: line 30164: 1252-001
_ZTCSt13basic_fstreamIcSt11char_traitsIcEE8_So.localalias.75 is defined already.
/tmp//ccyAATFr.s: line 30223: 1252-001
_ZTCSt13basic_fstreamIcSt11char_traitsIcEE0_Si.localalias.74 is defined already.
/tmp//ccyAATFr.s: line 30263: 1252-001
_ZTCSt14basic_ofstreamIwSt11char_traitsIwEE0_St13basic_ostreamIwS1_E.localalias.80
is defined already.
/tmp//ccyAATFr.s: line 30323: 1252-001
_ZTCSt13basic_fstreamIwSt11char_traitsIwEE8_St13basic_ostreamIwS1_E.localalias.84
is defined already.
/tmp//ccyAATFr.s: line 30388: 1252-001
_ZTCSt14basic_ifstreamIwSt11char_traitsIwEE0_St13basic_istreamIwS1_E.localalias.78
is defined already.
/tmp//ccyAATFr.s: line 30436: 1252-001
_ZTCSt13basic_fstreamIwSt11char_traitsIwEE0_St13basic_istreamIwS1_E.localalias.83
is defined already.
David, this looks like a bug in the AIX target output macros. I get:
.set
_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si.localalias.69,_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si
(this is correct since localalias is really an alias)
_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si.localalias.69:
.space 40
_ZTCSt14basic_ifstreamIcSt11char_traitsIcEE0_Si:
...
This is wrong, since we should not try to out the variable at least if I read
AIX assembly correctly.
varpool has explicit test to not output any aliases, so perhaps this is a bug
in wrapup_globals
and AIX output macros. I will try to track more after my teaching tonight.
Any update?
I've managed to generate a simple test case from
libstdc++-v3/src/c++98/strstream.cc which reproduces the issue on ARM
that Ramana has reported previously:
template<class _CharT> struct char_traits;
template<typename _CharT, typename _Traits>
class basic_ios
{
};
template<typename _CharT, typename _Traits = char_traits<_CharT> >
class basic_istream : virtual public basic_ios<_CharT, _Traits>
{
protected:
int _M_gcount;
virtual ~basic_istream()
{ }
};
class istrstream : public basic_istream<char>
{
virtual ~istrstream();
};
istrstream::~istrstream()
{
}
------------------ CUT ------------------
With an arm-none-linux-gnueabi gcc configured as:
./gcc/configure --target=arm-none-linux-gnueabi
--enable-gnu-indirect-function --enable-shared --with-arch=armv7-a
--with-fpu=vfpv3-d16 --with-float=softfp --with-arch=armv7-a
(irrelevant parts omitted)
With the following command line options:
-fdata-sections -O2 -fPIC -S ./test.cpp
We'll see
./test.cpp:17:7: error: istrstream::_ZTV10istrstream.localalias.0 causes
a section type conflict with istrstream::_ZTV10istrstream
class istrstream : public basic_istream<char>
^
./test.cpp:17:7: note: 'istrstream::_ZTV10istrstream' was declared here
Yufeng
