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Re: Avoid privatization of TLS variables


> 
> I'm not sure because my line numbers don't match.  If it is this
> assert:
> 
>     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
>       if (tls_segment == NULL)
> 	{
> 	  gold_assert(parameters->errors()->error_count() > 0
> 		      || issue_undefined_symbol_error(gsym));
> 	  return;
> 	}
>       value -= tls_segment->memsz();
>       Relocate_functions<size, false>::rela32(view, value, addend);
>       break;

I looked it up and it was the place I got ICE, too.
> 
> then the problem is that there is a TPOFF32 relocation but none of the
> input files has a section with the SHF_TLS flag set.  This should not
> be possible--the TPOFF32 relocation implies a TLS variable, but the
> absence of any SHF_TLS sections implies that there are no TLS
> variables.
I get:
a.o:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <main>:
   0:   55                      push   %rbp
   1:   48 89 e5                mov    %rsp,%rbp
   4:   64 48 8b 04 25 00 00    mov    %fs:0x0,%rax
   b:   00 00 
                        9: R_X86_64_TPOFF32     __gcov_indirect_call_counters_ltopriv
   d:   64 48 8b 14 25 00 00    mov    %fs:0x0,%rdx
  14:   00 00 
                        12: R_X86_64_TPOFF32    __gcov_indirect_call_callee_ltopriv
  16:   48 89 d1                mov    %rdx,%rcx
  19:   ba 00 00 00 00          mov    $0x0,%edx
                        1a: R_X86_64_32 main
  1e:   be eb 72 70 06          mov    $0x67072eb,%esi
  23:   48 89 c7                mov    %rax,%rdi
  26:   e8 00 00 00 00          callq  2b <main+0x2b>
                        27: R_X86_64_PC32       __gcov_indirect_call_profiler+0xfffffffffffffffc
  2b:   64 48 c7 04 25 00 00    movq   $0x0,%fs:0x0
  32:   00 00 00 00 00 00 
                        30: R_X86_64_TPOFF32    __gcov_indirect_call_callee_ltopriv
  38:   bf 00 00 00 00          mov    $0x0,%edi
                        39: R_X86_64_32 .bss+0x8
  3d:   e8 00 00 00 00          callq  42 <main+0x42>
                        3e: R_X86_64_PC32       __gcov_time_profiler+0xfffffffffffffffc
  42:   ba 00 00 00 00          mov    $0x0,%edx
  47:   48 8b 05 00 00 00 00    mov    0x0(%rip),%rax        # 4e <main+0x4e>
                        4a: R_X86_64_PC32       .bss+0xfffffffffffffffc
  4e:   48 83 c0 01             add    $0x1,%rax
  52:   48 89 05 00 00 00 00    mov    %rax,0x0(%rip)        # 59 <main+0x59>
                        55: R_X86_64_PC32       .bss+0xfffffffffffffffc
  59:   89 d0                   mov    %edx,%eax
  5b:   5d                      pop    %rbp
  5c:   c3                      retq   

000000000000005d <_GLOBAL__sub_I_65535_0_main>:
  5d:   55                      push   %rbp
  5e:   48 89 e5                mov    %rsp,%rbp
  61:   bf 00 00 00 00          mov    $0x0,%edi
                        62: R_X86_64_32 .data+0x40
  66:   e8 00 00 00 00          callq  6b <_GLOBAL__sub_I_65535_0_main+0xe>
                        67: R_X86_64_PC32       __gcov_init+0xfffffffffffffffc
  6b:   5d                      pop    %rbp
  6c:   c3                      retq   


and in asm:
        .file   "ccstYwxO.ltrans0.o"
        .text
        .globl  main
        .type   main, @function
main:
.LFB0: 
        .cfi_startproc
        pushq   %rbp
        .cfi_def_cfa_offset 16
        .cfi_offset 6, -16
        movq    %rsp, %rbp
        .cfi_def_cfa_register 6
        movq    %fs:__gcov_indirect_call_counters_ltopriv@tpoff, %rax
        movq    %fs:__gcov_indirect_call_callee_ltopriv@tpoff, %rdx
        movq    %rdx, %rcx
        movl    $main, %edx
        movl    $108032747, %esi
        movq    %rax, %rdi
        call    __gcov_indirect_call_profiler
        movq    $0, %fs:__gcov_indirect_call_callee_ltopriv@tpoff
        movl    $__gcov8.main, %edi
        call    __gcov_time_profiler
        movl    $0, %edx
        movq    __gcov0.main(%rip), %rax
        addq    $1, %rax
        movq    %rax, __gcov0.main(%rip)
        movl    %edx, %eax
        popq    %rbp
        .cfi_def_cfa 7, 8
        ret
        .cfi_endproc
.LFE0: 
        .size   main, .-main
        .hidden __gcov_indirect_call_callee_ltopriv
        .tls_common     __gcov_indirect_call_callee_ltopriv,8,8
        .hidden __gcov_indirect_call_counters_ltopriv
        .tls_common     __gcov_indirect_call_counters_ltopriv,8,8
        .local  __gcov0.main
        .comm   __gcov0.main,8,8
        .local  __gcov8.main
        .comm   __gcov8.main,8,8
        .type   _GLOBAL__sub_I_65535_0_main, @function
...


Honza
> 
> Why would there be a TPOFF32 relocation in the simple test case from
> Markus?
> 
> If that is not the assertion, let me know what is.
> 
> Ian

Attachment: a.o
Description: application/object


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