[Bug target/47378] New: ld warning linking with libgo.so: relocation bound to a symbol with STV_PROTECTED visibility

[Bug target/47378] New: ld warning linking with libgo.so: relocation bound to a symbol with STV_PROTECTED visibility

[ro at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47378

           Summary: ld warning linking with libgo.so: relocation bound to
                    a symbol with STV_PROTECTED visibility
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ro@gcc.gnu.org
                CC: iant@google.com
              Host: *-*-solaris2.*
            Target: *-*-solaris2.*
             Build: *-*-solaris2.*


While linking some libgo testcases when using Sun ld, I get linker warnings
like

ld: warning: relocation warning: R_386_COPY: file
/vol/gcc/obj/gcc-4.6.0-20101223/11-gcc-go/i386-pc-solaris2.11/libgo/.libs/libgo.so:
symbol __go_tdn_libgo_reflect.reflect.Type: relocation bound to a symbol with
STV_PROTECTED visibility

The symbol goes into the .data.rel.ro section

$ elfdump -s .libs/libgo.so |grep __go_tdn_libgo_reflect.reflect.Type
    [6203]  0x00472720 0x00000028  OBJT GLOB  P    1 .data.rel.ro  
__go_tdn_libgo_reflect.reflect.Type
   [52554]  0x00472720 0x00000028  OBJT GLOB  P    0 .data.rel.ro  
__go_tdn_libgo_reflect.reflect.Type

which is read-write

$ elfdump -c -N .data.rel.ro .libs/libgo.so

Section Header[33]:  sh_name: .data.rel.ro
    sh_addr:      0x46c8a0        sh_flags:   [ SHF_WRITE SHF_ALLOC ]
    sh_size:      0x14dc8         sh_type:    [ SHT_PROGBITS ]
    sh_offset:    0x45c8a0        sh_entsize: 0
    sh_link:      0               sh_info:    0
    sh_addralign: 0x20      

This section goes into a read-write segment:

$ elfdump --segments .libs/libgo.so

File: .libs/libgo.so

Elf file type is DYN (Shared object file)
Entry point 0x0
There are 5 program headers, starting at offset 52

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x000000 0x00000000 0x00000000 0x3c5840 0x3c5840 R E 0x10000
  LOAD           0x3c5840 0x003d5840 0x00000000 0x1222b4 0x13918c RWE 0x10000
  DYNAMIC        0x0000d4 0x000000d4 0x00000000 0x00178 0x00000 RWE 0
  TLS            0x4e7af0 0x004f7af0 0x00000000 0x00004 0x00008 RW  0x4
  LOOS+464e550   0x00024c 0x0000024c 0x00000000 0x0a94c 0x0a94c R   0x4
 Section to Segment mapping:
  Segment Sections...
   00     .dynamic .eh_frame_hdr .hash .SUNW_ldynsym .dynsym .dynstr
.SUNW_version .SUNW_versym .SUNW_dynsymsort .SUNW_dyntlssort .SUNW_reloc
.rel.plt .plt .text .init .fini .text.unlikely .rodata .rodata.str1.1
.rodata.str1.4 .rodata.cst4 .rodata.cst8 .rodata.cst16 
   01     .got .eh_frame .gcc_except_table .data .bssf .picdata .ctors .dtors
.jcr .data.rel.ro .data.rel.ro.local .data.rel.local .data.rel .tdata .bss 
   02     
   03     .tdata .tbss 
   04     .eh_frame_hdr 

It's exactly the same with gld 2.21 instead: the symbol goes into .data.rel.ro,
the section is read-write, and the section goes into a read-write segment:

$ readelf --segments .libs/libgo.so

File: .libs/libgo.so

Elf file type is DYN (Shared object file)
Entry point 0x1c4380
There are 5 program headers, starting at offset 52

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x000000 0x00000000 0x00000000 0x3aacb4 0x3aacb4 R E 0x1000
  LOAD           0x3aacb4 0x003abcb4 0x003abcb4 0x11fe50 0x136d6c RW  0x1000
  DYNAMIC        0x47e3e8 0x0047f3e8 0x0047f3e8 0x000e8 0x000e8 RW  0x4
  TLS            0x3e966c 0x003ea66c 0x003ea66c 0x00004 0x00008 R   0x4

 Section to Segment mapping:
  Segment Sections...
   00     .hash .dynsym .dynstr .gnu.version .gnu.version_r .rel.dyn .rel.plt
.init .plt .text .fini .rodata .eh_frame_hdr 
   01     .eh_frame .gcc_except_table .tdata .ctors .dtors .jcr .data.rel.ro
.dynamic .got .data .bss 
   02     .dynamic 
   03     .tdata .tbss 
   04     .eh_frame_hdr 

although (unlike Sun ld, that doesn't care about section names, only access
rights) gld knows about .data.rel.ro.

This should be avoided somehow since, given the information it has, Sun ld
is perfectly right to warn about the relocation.

See also

http://gcc.gnu.org/ml/gcc-patches/2011-01/msg01358.html

[Bug go/47378] ld warning linking with libgo.so: relocation bound to a symbol with STV_PROTECTED visibility

[ian at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47378

--- Comment #1 from ian at gcc dot gnu.org <ian at gcc dot gnu.org> 2011-02-08 20:55:07 UTC ---
Author: ian
Date: Tue Feb  8 20:55:02 2011
New Revision: 169946

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=169946
Log:
    PR go/47378
Don't use protected visibility for type descriptors.

Modified:
    trunk/gcc/go/gofrontend/gogo-tree.cc

[Bug go/47378] ld warning linking with libgo.so: relocation bound to a symbol with STV_PROTECTED visibility

[ian at airs dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47378

Ian Lance Taylor <ian at airs dot com> changed:

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

--- Comment #2 from Ian Lance Taylor <ian at airs dot com> 2011-02-08 20:55:34 UTC ---
Should be fixed.