<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/64571>64571</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            ld.lld: ALIGN() directive incorrectly increasing LMA after empty section
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
      </td>
    </tr>

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

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

<pre>
    An ALIGN() directive applied to the LMA of an empty section will influence the LMA of the next non-empty section that follows. 

However, when using GCC/ld, in this scenario, the next non-empty section's LMA will begin at the last available LMA address prior to the ALIGN occurirng on the empty section's LMA.

For a simplified example, I modified [a sample project from the embedded toolchain](https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/tree/main/samples/src/baremetal-uart).

Changes:
1. Add map file generation to the build target of the [Makefile](https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/blob/main/samples/src/baremetal-uart/Makefile) - `$(BIN_PATH)/clang $(MICROBIT_TARGET) $(CRT) -g -Xlinker -Map=hello.map -T ../../ldscripts/microbit.ld -o hello.elf $^`
2. Add the `align_bug` section to `/opt/LLVMEmbeddedToolchainForArm-17.0.0-Linux-x86_64/lib/clang-runtimes/arm-none-eabi/armv6m_soft_nofp/lib/picolibcpp.ld`

**Actual Result**: LMA of `.data` is the aligned LMA of empty section `.align_bug`
```
    3320     3320       28     4 .except_unordered
 3320     3320        0     1         . = ALIGN ( 8 )
    3320     3320 28     4         <internal>:(.ARM.exidx)
20000000     3350        0 16 .align_bug
20000000     3350        0     1         . = .
20000000 3350       38     4 .data
20000000     3350       30     4 /tmp/hello-6adfd4.o:(.data)
20000000     3350        4     1 gpio_dir_set
20000004     3354        4     1 uart_starttx
20000008     3358        4     1 uart_txdrdy
``` 

**Expected Result**: LMA of `.data` is the the address immediately following 0x3320 + 0x28 (LMA of `.except_unordered` + size of `.except_unordered`)
```
    3320     3320       28     4 .except_unordered
    3320     3320        0     1         . = ALIGN ( 8 )
    3320     3320       28     4 <internal>:(.ARM.exidx)
20000000     3348       38     4 .data
20000000 3348       30     4         /tmp/hello-dc4e29.o:(.data)
20000000 3348        4     1                 gpio_dir_set
20000004     334c 4     1                 uart_starttx
20000008     3350        4     1 uart_txdrdy
```

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJysVluPozoS_jXOSwkE5hJ4yEP6kjktdZ9dtVqrfYsMLoh3jI1s053eX7-ySTJJX07P7BkUBRvqK1d9_soFs1b0CnFFiitS3CzY5HbarDqh2t3310Wj-etqrWB9f_ftT0IrQmvgwmDrxDMCG0cpkIPT4HYI9w9r0B0wBTiM7hWsN9MKXoSUIFQnJ1Qtnpv6ocK9A6VVdAlyO-ag01LqFxsDSW5Isp7__9Av-IyG0Gt42aGCyQrVw7fra0I3kvvHwsOFBduiYkZo_-zzpQhd2hBQiLPBXihgLgAksw7YMxOSNXKOmnFu0FoYjdDmmHmgB3TbTkYY1UOIH-HDZeLzXDbaAAMrhlGKzlOJezaMEn3EdzBoPj8lxRUDG97AaPR_sHXQGT0cVmmQ87ANWrY7JhQpbgitds6NlmRrQjeEbnrhdlMTt3ogdLN-fIis7twLM0jo5v7-Xw_R0U10chN12kRr4wHOoDccvHO6mSOxfmRaQjcNMzigYzKamHGE1hc5Xu-Y6jFEEuZpDGvOYWAjdEIi9KjQsHnTZzqbSUgOjpke3VEmpLh6YN_RI35_eo3Uzc-ntzkFQmuIgJQJoTmh1dXdn9t_rp_-ILQmdNNKpnqY3zzcXT_-4-ruafu0fvx2--Rx84vrxzCJeoj-LYX6jgaiBzaS7GaHUurYkxQ9QRwTugl_ktvWiNH56AbRGt0IF0sOkYYZgbILvotbH1cgnM6EBxbLhEnRq20z9aRMflSbntPY6NEdGLs9EPZ05GujzdoMUbqMkziJ7oWa9tG-Krdl7uMSzTHnyEzKiSEQyMwQKa0wQtaIef5cDlu_OVulu_GEHEWrpWjacYwlP0VOaEqKKzGw_utNl_L5eIsONeIXtBYDWWlWL-uipgWhmyXjHW-xipKMN1FepDSqqy6Lkjbjy2VWsjpN_CaeiZhQ_1u3bmISHtFO0s2PSLY-nmakTGLOHPPEChv4DmQjP1pcHnHe_nw3DiuVyeEXpgAAWUYTuBgA0Crccohx3-LotpPShqNBfsB9BIJ5kB6nEAPJbg7HF6EVVHDK-_3CpyWPF8muhXJoFJMkuw3bUsXrx4cY94LvT55oMl8HT8VZNGkJZxR8Zf1R7PEb1BkiO1EUduUvvWfJwdYfdoPXZSinqPRSyWN9SC44-jKv_BBpPwq95cJsLboLSH6E5G8h_oTZWseMc_sLSHWEVB9C3J4b_vpGQfBewbf7EVuH_Bc0HHR86HpiGJAL5lC-Hpqz773JPuiD0CtI9tRrqDpz906f5WxqxX_xL2x-FOBvKohPcH-vJt6s_f9VRF79jGLP7ZK3lXipWt7mSOsvVHvm76Slt9eXCs7bT7FfS_ldwXwu5Xm64KuM11nNFrhKyzot06RcVovdqm7yrMY0r1nOi4R2aZOziqUFFrzDCouFWNGEZkmV1GldpGkV511bd03blFjzvFrmJE9wYELGvoHE2vQLYe2EqzIvlulCsgalPX4km1XoMs3UW5InUlhnf8CccBJXksdScl9YH386C9Vq4yfy1Y8NsvAVG74wO4fmslUsJiNXv9z7QgK-94Uc_hcAAP__jP5gsw">