<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/141051>141051</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            xray incorrectly generates tailcall sled kind as exit kind in aarch64 target
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          quininer
      </td>
    </tr>
</table>

<pre>
    ```c
__attribute__ ((noinline)) 
int fx(unsigned int a) { 
  return a + 1; 
} 

int foo(unsigned int a) { 
  return fx(a); 
}
```

Compile the above code using the command

```shell
clang foo.c -shared -O2 -fxray-instrument -fxray-instruction-threshold=1 -fuse-ld=lld -nostdlib
```

output

```asm
000000000001047c <foo>:
   1047c: 14000008      b       0x1049c <foo+0x20>
   10480: d503201f      nop
   10484: d503201f      nop
   10488: d503201f      nop
   1048c: d503201f      nop
   10490: d503201f      nop
   10494: d503201f      nop
   10498: d503201f      nop
   1049c: 14000008      b       0x104bc <foo+0x40>
   104a0: d503201f      nop
   104a4: d503201f      nop
   104a8: d503201f      nop
   104ac: d503201f      nop
   104b0: d503201f      nop
   104b4: d503201f      nop
   104b8: d503201f      nop
   104bc: 14000009      b       0x104e0 <fx@plt>
```

You can see that this generates a tail call from function `foo` to function `fx`, but it is reported as exit kind in `xray_instr_map`.

```shell
$ llvm-xray extract a.out --output=-
---
- { id: 1, address: 0x10434, function: 0x10434, kind: function-enter, always-instrument: false, function-name: '', version: 2 }
- { id: 1, address: 0x10458, function: 0x10434, kind: function-exit, always-instrument: false, function-name: '', version: 2 }
- { id: 2, address: 0x1047C, function: 0x1047C, kind: function-enter, always-instrument: false, function-name: '', version: 2 }
- { id: 2, address: 0x1049C, function: 0x1047C, kind: function-exit, always-instrument: false, function-name: '', version: 2 }
...
```

The same code and compiler arguments will correctly generate and report as tailcall kind on x86_64 linux.



</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJy8ls9yq7gSxp9G3nRBCfF_wcJJbrZ3M5tZuSRojGaE5JFEQt5-SrKdxE7mMGdxhqKgaHW3fnzFJ8Gdk0eN2JHygZRPO774ydjur0VqqdHuhBneOlLR89kTuj8cuPdWisXj4QCENYQ12kitpEbCWsJaIHQvtYdxJaxZdJxggBDhcbR-CBkAFv1iNXAg7AEykscwqZ_i7dLCmH_VI04VRj66hOuV-9zw0cwnqRD8hMCFeUHozYCwOKmPMdibeeZ6OGe_F7sJlSJ03yuuj4Eo7SFxE7c4QPJ_Bsm4Wv6WSO28XWbU_jbSe2l04ieLbjJqIPlTBsm4OEzig1IDJNo4PygpvjKbxZ8Wf0fE3Uzonn4cGS3qHkj-GPTK_0fyfRQHYpzke8iKmNdAOAhtBaEtXTNatO9l7IGujIbqa2lDQ-lQ0pzRbLyWanP6yCg2M5rNjP4m42603WRoNxnaTYb2xyKJG5GKG5H4JiDfBOTNjyTg_Va92GQQmwxiUyTxWaT2RiCkUaCVFPSk_Fmeuw_5d7NAzzU4DAbkHvwkHRxRo-UeHXDwXCrouVIwWjPDuOhoHSAVDdJXFLy5ja6hO3sEsXiQHqQDiydjPQ7AHeAqPfwpdVg2Qnrw5CF68jDzE6lo-g9GJ6wApV7mJFQArt7y3gNPzeIhSS6OzJ8SQvdJEq9xPZJD1CcA8WGw6Fx4jvrkRYhe2e_CATGErsMJao82tlGv_M19WlliGlcOP7dLNJ8xjBBWx_MRXtC6y0QMzmvhJmPZ_BTjKv2vRGTfIdaP3yKew_-9jN8ytj_H-AtkTNP0q_1-mxAcny9bHtdD2OzCbmiB22Oc0sGrVAp6Yy32Xr29mzOmn50VfBV8Gm0avWU0rE11qApQUi_r1VN0vxu6fGjzlu-wy-qibrOyrerd1NGW1yOvCxRjKcamHMexZpngoinyEctmJztGWUlLxjKWsaJK-76oGKOFELTNRFWQguLMpUqDS1Njjzvp3IJdVmS0zHaKC1Qu_tEwpvEV4ihhLPzg2C5aWyxHRwqqpPPuo42XXmEXbS_1VyE-vbtTOJwFuF9pOLf9VBXguT2i3y1WdZP3p_CFEPZM2PNR-mkRaW9mwp7D1JdbcrLmD-w9Yc8R2BH2fHmjl479HQAA___0v8Oq">