Issue 146542
Summary [BUG][RISCV][BOLT] Incorrect GOT Relocation Handling in some case
Labels BOLT
Assignees
Reporter dinyy
    I use the newest version clang and gcc(main branch ) to complie mysql-8.0.33. And bolt failed to deal with mysql. When I run this command:

> llvm-bolt mysqld  -o mysqld.test

It occuers that:

> Segmentation fault

After use gdb to debug , I found that R_RISCV_GOT_HI20 Relocation Handling failed .
Bolt think when occur GOT relocation infomation , always find 2 instruction to get imm, and transform the symbole to __BOLT_got_zero + offset  , the code  is in  `bolt\lib\Core\BinaryFunction.cpp` and `bolt\lib\Core\Relocation.cpp.` To deal with this case:

>  2242d12:       01620797                auipc   a5,0x1620
                        2242d12: R_RISCV_GOT_HI20       _ITM_deregisterTMCloneTable
                        2242d12: R_RISCV_RELAX  *ABS*
 2242d16:       7de7b783                ld      a5,2014(a5) # 38634f0 <_ITM_deregisterTMCloneTable@Base>


but the mysqld binary which is compiled by newest clang and gcc , will occur this case:

>  0000000002244c08 <.Lpcrel_hi153>:

 2244c08:       01621617                auipc   a2,0x1621
                        2244c08: R_RISCV_GOT_HI20       connection_events_loop_aborted_flag
 2244c0c:       66a1                    **lui     a3,0x8**
 0000000002244c0e <.Lpcrel_hi154>:
 2244c0e:       01621717                auipc   a4,0x1621
                        2244c0e: R_RISCV_GOT_HI20       log_output_options
0000000002244c12 <.Lpcrel_hi155>:
 2244c12:       01621797                auipc   a5,0x1621
                        2244c12: R_RISCV_GOT_HI20       query_logger
 2244c16:       f2a50b93                addi    s7,a0,-214 # 3c09b28 <.L_MergedGlobals.1012>
                        2244c16: R_RISCV_PCREL_LO12_I   .Lpcrel_hi151
                        2244c16: R_RISCV_RELAX  *ABS*
 2244c1a:       d2458d93                addi    s11,a1,-732 # fb9928 <.LJTI30_0>
                        2244c1a: R_RISCV_PCREL_LO12_I   .Lpcrel_hi152
                        2244c1a: R_RISCV_RELAX  *ABS*

I try to fix it by find auipc+ld pattern when the relocation is about GOT in  `bolt\lib\Core\BinaryFunction.cpp` ,but failed.  Now I need some help to fix this bug.  Could someone help me?
And I want to use `bolt/utils/bughunter.sh` on RISCV , but failed. It couldn't work because `createRelocation` and `encodeValueRISCV` not implemented. Are there any way to trace the bug?

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