[Bug gold/26972] New: R_X86_64_TLSDESC_CALL/R_X86_64_GOTPC32_TLSDESC need improvement

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26972

            Bug ID: 26972
           Summary: R_X86_64_TLSDESC_CALL/R_X86_64_GOTPC32_TLSDESC need
                    improvement
           Product: binutils
           Version: 2.36 (HEAD)
            Status: NEW
          Severity: normal
          Priority: P2
         Component: gold
          Assignee: ccoutant at gmail dot com
          Reporter: hjl.tools at gmail dot com
                CC: ian at airs dot com
  Target Milestone: ---
            Target: x86-65

tls_shared_gnu2_test failed on CET enabled Tiger Lake machine when binutils is
compiled with -fcf-protection:

Dump of assembler code for function _Z2t1v:
   0x00007ffff77c4d10 <+0>:     endbr64
   0x00007ffff77c4d14 <+4>:     sub    $0x8,%rsp
   0x00007ffff77c4d18 <+8>:     lea    0x22f9(%rip),%rax        #
0x7ffff77c7018
 <v1@got.plt>
   0x00007ffff77c4d1f <+15>:    call   *(%rax)
=> 0x00007ffff77c4d21 <+17>:    add    %fs:0x0,%rax

Gold resolves v1@got.plt in

0000000000000000 <_Z2t1v>:
   0:   f3 0f 1e fa             endbr64 
   4:   48 83 ec 08             sub    $0x8,%rsp
   8:   48 8d 05 00 00 00 00    lea    0x0(%rip),%rax        # f <_Z2t1v+0xf>  
b: R_X86_64_GOTPC32_TLSDESC     v1-0x4
   f:   ff 10                   call   *(%rax)  f: R_X86_64_TLSDESC_CALL       
v1

to the first entry of PLT without endbr64

(gdb) disass 0x00007ffff77c4c10,+16
Dump of assembler code from 0x7ffff77c4c10 to 0x7ffff77c4c20:
=> 0x00007ffff77c4c10:  push   0x23da(%rip)        # 0x7ffff77c6ff0
<_GLOBAL_OFF
SET_TABLE_+8>
   0x00007ffff77c4c16:  bnd jmp *0x23c3(%rip)        # 0x7ffff77c6fe0
   0x00007ffff77c4c1d:  nopl   (%rax)
End of assembler dump.
(gdb) 

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff77c4c10 in ?? () from ./tls_test_gnu2_shared.so
(gdb) bt
#0  0x00007ffff77c4c10 in ?? () from ./tls_test_gnu2_shared.so
#1  0x00007ffff77c4d21 in t1 ()
    at /export/gnu/import/git/gitlab/x86-binutils/gold/testsuite/tls_test.cc:87
#2  0x000000000040121f in thread_routine (arg=arg@entry=0x0)
    at
/export/gnu/import/git/gitlab/x86-binutils/gold/testsuite/tls_test_main.c
c:87
#3  0x0000000000400ebf in main ()
    at
/export/gnu/import/git/gitlab/x86-binutils/gold/testsuite/tls_test_main.c
c:122
(gdb)

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