[Bug lto/50483] New: lto turns visibility from HIDDEN to DEFAULT

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* [Bug lto/50483] New: lto turns visibility from HIDDEN to DEFAULT
@ 2011-09-22 11:26 vincenzo.innocente at cern dot ch
  2011-09-25 12:04 ` [Bug lto/50483] " rguenth at gcc dot gnu.org
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: vincenzo.innocente at cern dot ch @ 2011-09-22 11:26 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50483

             Bug #: 50483
           Summary: lto turns visibility from HIDDEN to DEFAULT
    Classification: Unclassified
           Product: gcc
           Version: lto
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: vincenzo.innocente@cern.ch
              Host: x86
            Target: x86_64-unknown-linux-gnu
             Build: 4.7.0 20110919


not sure how relevant is in practice BUT in the example below one may notice
that the visibility of "bar" is turned to DEFAULT by lto
no lto
17: 0000000000000597    11 FUNC    LOCAL  HIDDEN    11 bar()
lto
11: 0000000000000597    11 FUNC    LOCAL  DEFAULT   11 bar() .2238


cat vislto.cc
void ext();
void bar() __attribute((visibility( "hidden" )));
void foo() __attribute((visibility( "default" )));

void foo() { bar();}
void bar() { ext();}
g++ -fPIC vislto.cc -Wall -shared -o libvislto.so
[vinavx0] ~/public/ctest $ readelf -sW libvislto.so | grep -v UND | sed 's/\./
\./g' | c++filt

Symbol table ' .dynsym' contains 11 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     2: 0000000000000478     0 FUNC    GLOBAL DEFAULT    9 _init
     3: 00000000000005e8     0 FUNC    GLOBAL DEFAULT   12 _fini
     6: 000000000000058c    11 FUNC    GLOBAL DEFAULT   11 foo()
     8: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS _edata
     9: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
    10: 00000000000018e0     0 NOTYPE  GLOBAL DEFAULT  ABS _end

Symbol table ' .symtab' contains 31 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     1: 00000000000004c0     0 FUNC    LOCAL  DEFAULT   11 call_gmon_start
     2: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS crtstuff .c
     3: 00000000000018a8     0 OBJECT  LOCAL  DEFAULT   19 __CTOR_LIST__
     4: 00000000000018b8     0 OBJECT  LOCAL  DEFAULT   20 __DTOR_LIST__
     5: 00000000000018c8     0 OBJECT  LOCAL  DEFAULT   21 __JCR_LIST__
     6: 00000000000004e0     0 FUNC    LOCAL  DEFAULT   11
__do_global_dtors_aux
     7: 00000000000018d0     1 OBJECT  LOCAL  DEFAULT   22 completed .5901
     8: 00000000000018d8     8 OBJECT  LOCAL  DEFAULT   22 dtor_idx .5903
     9: 0000000000000560     0 FUNC    LOCAL  DEFAULT   11 frame_dummy
    10: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS vislto .cc
    11: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS crtstuff .c
    12: 00000000000018b0     0 OBJECT  LOCAL  DEFAULT   19 __CTOR_END__
    13: 0000000000000650     0 OBJECT  LOCAL  DEFAULT   13 __FRAME_END__
    14: 00000000000018c8     0 OBJECT  LOCAL  DEFAULT   21 __JCR_END__
    15: 00000000000005b0     0 FUNC    LOCAL  DEFAULT   11
__do_global_ctors_aux
    16: 00000000000018a0     0 OBJECT  LOCAL  HIDDEN    18 __dso_handle
    17: 0000000000000597    11 FUNC    LOCAL  HIDDEN    11 bar()
    18: 00000000000018c0     0 OBJECT  LOCAL  HIDDEN    20 __DTOR_END__
    19: 0000000000001670   496 OBJECT  LOCAL  HIDDEN    15 _DYNAMIC
    20: 0000000000001878    40 OBJECT  LOCAL  HIDDEN    17
_GLOBAL_OFFSET_TABLE_
    22: 0000000000000478     0 FUNC    GLOBAL DEFAULT    9 _init
    23: 00000000000005e8     0 FUNC    GLOBAL DEFAULT   12 _fini
    26: 000000000000058c    11 FUNC    GLOBAL DEFAULT   11 foo()
    28: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS _edata
    29: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
    30: 00000000000018e0     0 NOTYPE  GLOBAL DEFAULT  ABS _end
[vinavx0] ~/public/ctest $ g++ -fPIC vislto.cc -Wall -shared -o libvislto.so
-flto
[vinavx0] ~/public/ctest $ readelf -sW libvislto.so | grep -v UND | sed 's/\./
\./g' | c++filt

Symbol table ' .dynsym' contains 11 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     2: 0000000000000478     0 FUNC    GLOBAL DEFAULT    9 _init
     3: 00000000000005e8     0 FUNC    GLOBAL DEFAULT   12 _fini
     6: 000000000000058c    11 FUNC    GLOBAL DEFAULT   11 foo()
     8: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS _edata
     9: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
    10: 00000000000018e0     0 NOTYPE  GLOBAL DEFAULT  ABS _end

Symbol table ' .symtab' contains 31 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     1: 00000000000004c0     0 FUNC    LOCAL  DEFAULT   11 call_gmon_start
     2: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS crtstuff .c
     3: 00000000000018a8     0 OBJECT  LOCAL  DEFAULT   19 __CTOR_LIST__
     4: 00000000000018b8     0 OBJECT  LOCAL  DEFAULT   20 __DTOR_LIST__
     5: 00000000000018c8     0 OBJECT  LOCAL  DEFAULT   21 __JCR_LIST__
     6: 00000000000004e0     0 FUNC    LOCAL  DEFAULT   11
__do_global_dtors_aux
     7: 00000000000018d0     1 OBJECT  LOCAL  DEFAULT   22 completed .5901
     8: 00000000000018d8     8 OBJECT  LOCAL  DEFAULT   22 dtor_idx .5903
     9: 0000000000000560     0 FUNC    LOCAL  DEFAULT   11 frame_dummy
    10: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS cclww4iv .ltrans0 .o
    11: 0000000000000597    11 FUNC    LOCAL  DEFAULT   11 bar() .2238
    12: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS crtstuff .c
    13: 00000000000018b0     0 OBJECT  LOCAL  DEFAULT   19 __CTOR_END__
    14: 0000000000000650     0 OBJECT  LOCAL  DEFAULT   13 __FRAME_END__
    15: 00000000000018c8     0 OBJECT  LOCAL  DEFAULT   21 __JCR_END__
    16: 00000000000005b0     0 FUNC    LOCAL  DEFAULT   11
__do_global_ctors_aux
    17: 00000000000018a0     0 OBJECT  LOCAL  HIDDEN    18 __dso_handle
    18: 00000000000018c0     0 OBJECT  LOCAL  HIDDEN    20 __DTOR_END__
    19: 0000000000001670   496 OBJECT  LOCAL  HIDDEN    15 _DYNAMIC
    20: 0000000000001878    40 OBJECT  LOCAL  HIDDEN    17
_GLOBAL_OFFSET_TABLE_
    22: 0000000000000478     0 FUNC    GLOBAL DEFAULT    9 _init
    23: 00000000000005e8     0 FUNC    GLOBAL DEFAULT   12 _fini
    26: 000000000000058c    11 FUNC    GLOBAL DEFAULT   11 foo()
    28: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS _edata
    29: 00000000000018d0     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
    30: 00000000000018e0     0 NOTYPE  GLOBAL DEFAULT  ABS _end


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug lto/50483] lto turns visibility from HIDDEN to DEFAULT
  2011-09-22 11:26 [Bug lto/50483] New: lto turns visibility from HIDDEN to DEFAULT vincenzo.innocente at cern dot ch
@ 2011-09-25 12:04 ` rguenth at gcc dot gnu.org
  2022-01-01 23:20 ` pinskia at gcc dot gnu.org
  2022-01-01 23:28 ` pinskia at gcc dot gnu.org
  2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-09-25 12:04 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50483

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |lto
                 CC|                            |hubicka at gcc dot gnu.org

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-09-25 11:58:40 UTC ---
Honza?


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug lto/50483] lto turns visibility from HIDDEN to DEFAULT
  2011-09-22 11:26 [Bug lto/50483] New: lto turns visibility from HIDDEN to DEFAULT vincenzo.innocente at cern dot ch
  2011-09-25 12:04 ` [Bug lto/50483] " rguenth at gcc dot gnu.org
@ 2022-01-01 23:20 ` pinskia at gcc dot gnu.org
  2022-01-01 23:28 ` pinskia at gcc dot gnu.org
  2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-01-01 23:20 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50483

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |INVALID
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So what is happening is bar is being coming localized to the newly produced
assembly file which is the same as being hidden really.

If we do:
void bar() __attribute((visibility( "hidden" ), externally_visible));

The new assembly file in both cases produces:
        .globl  _Z3barv
        .hidden _Z3barv

Without the externally_visible, the function does not have a .globl to it.
This is also why in both with and without -flto dynsym does not have the symbol
there.

There is no bug to be fixed, LTO is doing the localizing rather than the linker
doing it.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug lto/50483] lto turns visibility from HIDDEN to DEFAULT
  2011-09-22 11:26 [Bug lto/50483] New: lto turns visibility from HIDDEN to DEFAULT vincenzo.innocente at cern dot ch
  2011-09-25 12:04 ` [Bug lto/50483] " rguenth at gcc dot gnu.org
  2022-01-01 23:20 ` pinskia at gcc dot gnu.org
@ 2022-01-01 23:28 ` pinskia at gcc dot gnu.org
  2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-01-01 23:28 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50483

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note I looked at both with and without the LTO plugin too to make sure it would
work in both cases.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-01-01 23:28 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-09-22 11:26 [Bug lto/50483] New: lto turns visibility from HIDDEN to DEFAULT vincenzo.innocente at cern dot ch
2011-09-25 12:04 ` [Bug lto/50483] " rguenth at gcc dot gnu.org
2022-01-01 23:20 ` pinskia at gcc dot gnu.org
2022-01-01 23:28 ` pinskia at gcc dot gnu.org

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