<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/63325>63325</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            MSAN fails on musl-based systems to due ifguard mismatch
        </td>
    </tr>

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

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

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

<pre>
    MSAN does presently not work on [musl](https://musl.libc.org)-based systems (e.g. [Alpine Linux](https://alpinelinux)):

```
$ cat test.c
#include <stdio.h>

int main(void) {
        char b[20];
 printf("%c\n", b[5]);
}
$ clang -fsanitize=memory -o test test.c
/usr/bin/ld: /usr/lib/llvm16/lib/clang/16/lib/linux/libclang_rt.msan-x86_64.a(msan_interceptors.cpp.o): in function `__interceptor_getrlimit64':
/home/buildozer/aports/main/llvm-runtimes/src/llvm-project-16.0.6.src/compiler-rt/lib/msan/msan_interceptors.cpp:833: undefined reference to `__sanitizer::struct_rlimit64_sz'
/usr/bin/ld: /usr/lib/llvm16/lib/clang/16/lib/linux/libclang_rt.msan-x86_64.a(msan_interceptors.cpp.o): in function `__interceptor_prlimit64':
/home/buildozer/aports/main/llvm-runtimes/src/llvm-project-16.0.6.src/compiler-rt/lib/msan/msan_interceptors.cpp:853: undefined reference to `__sanitizer::struct_rlimit64_sz'
/usr/bin/ld: /home/buildozer/aports/main/llvm-runtimes/src/llvm-project-16.0.6.src/compiler-rt/lib/msan/msan_interceptors.cpp:853: undefined reference to `__sanitizer::struct_rlimit64_sz'
/usr/bin/ld: /home/buildozer/aports/main/llvm-runtimes/src/llvm-project-16.0.6.src/compiler-rt/lib/msan/msan_interceptors.cpp:855: undefined reference to `__sanitizer::struct_rlimit64_sz'
clang-16: error: linker command failed with exit code 1 (use -v to see invocation)
```

This is due to an ifguard mismatch:

https://github.com/llvm/llvm-project/blob/9aa026e9ffc32f1d0531abd306933e249fdc8059/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp#L276

and:

https://github.com/llvm/llvm-project/blob/9aa026e9ffc32f1d0531abd306933e249fdc8059/compiler-rt/lib/msan/msan_interceptors.cpp#L825

Here is a git-format-patch which fixes this issue:

```diff
>From 8904ed80c262e973c0da7758337f586c9854f38a Mon Sep 17 00:00:00 2001
From: Sören Tempel <soeren+git@soeren-tempel.net>
Date: Thu, 15 Jun 2023 09:28:57 +0200
Subject: [PATCH] msan: fix ifdef guard for getrlimit etc interceptors

These interceptors need struct_ustat_sz, struct_rlimit64_sz, and
struct_statvfs64_sz which are defined in the following file:

        compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp

However, these variables are only defined for GLIBC sanitizers.
As such, if we attempt to use MSAN on a Linux system that does not
utilize glibc (e.g. Alpine Linux) then we will get a linker error
complaining about undefined references to __sanitizer::struct_rlimit64_sz
and __sanitizer::struct_rlimit64_sz.

This patch fixes this by only defining the interceptors that require
these constants if SANITIZER_GLIBC is defined. Thereby aligning the
macro guards of msan_interceptors.cpp with those of
sanitizer_platform_limits_posix.cpp.
---
 compiler-rt/lib/msan/msan_interceptors.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
index 6f57c33ee..349eff549 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -822,7 +822,7 @@ INTERCEPTOR(int, getrlimit, int resource, void *rlim) {
 INTERCEPTOR_GETRLIMIT_BODY(getrlimit, resource, rlim);
 }
 
-#if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
+#if SANITIZER_GLIBC
 INTERCEPTOR(int, __getrlimit, int resource, void *rlim) {
 INTERCEPTOR_GETRLIMIT_BODY(__getrlimit, resource, rlim);
 }
```

This patch is presently [applied for the Alpine downstream package](https://git.alpinelinux.org/aports/commit/?id=5ecc3adbbc5ecd614199aa0ff9ece5fe4b43a097).
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsWFuPozgW_jWul6MgYgOBh3rIpTJTq-6eUVdedl8iYw6Jt8FmbVOX_vWrAySVuvSqp3d2NCtNKaKCTQ7fuX3-bOm9PhjEa5auWLq5kn04WndtWuzbq9JWT9cf75afoLLooXPo0YTmCYwN8GDdF7AGWLpqe9-wdMN4fgyh80wsGd8yvqXxqNGliqw7MF7MSumxAv_kA7YeGM8xOkRkYdl02iB80KZ_fM-SHOabYZoX9BFLFm9YfLpm8fQZb3kCSgYI6EOkTmNCG9X0FQITax8qbaMjEzeXZrQJ0EptGM_vra4YL4AtVuMcTH_qKB2ULF3xmJCK03TntAk14znjnPFUsXRthq_r4el0cKs4P88WmwusjTQHmNVeGh30V2Ri02Jr3RPM7ODEK0-2vXeMb0tCum0qJpZwHmx0Sdfmvp1n59vhBYxvL4amYNLdMLt3IWq9NLPHPNtnSSQZz-l-r01Ap7AL1vlIdV1kx_iDNlD3RgVNVZDF-8sn9wcMrtGtDlnC-OI5XXx7tC0S-F43lf2KhFl21gVPFSNHl5r7duZ6E3SLNOydOo12zv4TVZjNsyiOsmicUbbtdINu5sLZP8I-_XvjAhPLXAjyoTcV1tpgBQ5rdGgUQrCjO6dsOEIvlj64XoX9yau9_0qO_f9kpPtz5yP9A_Lxl6t_uKvp7-fq0BSzeUYW0TlLv4BGmy_oQNm2laaCWuoGK3jQ4Qj4qAMoWyHMaa3pPcLsnt7rEUGbe6skdQr1zruLyHDdHbUH7aHqB8jSgK4PvXQVtNq3Mqjjq6Xo5cJ10OHYl5Gy7RTaVxGmFDWWIllIGfMMi7pWgtfzKk7FXJaViLNCCORJUVcqj9PiG4k4h3FPoSCvLoa6RobaunY_RNXvO-v145AiLj7wRXaJX5rqz-HRfywtLj7kPL1E-TM6pERJOOgwI29lmHWUIHg4anWEWj-ihzDm0_f4LQlR6boeh7bOtpAXcYJVHiuecSwWQsWVXCzSXIhFneaZKvI0qUUu4aM1cIcdzBcQx0wspwvwOJ4_26OavWNrwVaZQwM7bDtsBkViqTEYXx10YEk83s7CMB8ZDGepspGBsMPu2JO4mKfwt94Aj7mAmFYBnjOxTBfA-Crm8VTMd305JIfIIV39utytf2bpBoYYiyXFBnRdYQ1jbdfWwXkFBwwKLjPwsj_Q44tZMEgib-zj3gcZhiZew3utvQaqt8HSNE0_uK_9MD9lTjqEE4FoA-GIUNumsQ_aHKDWzZtUxsXv2CKXNWYf8J64dE0gPMK9dFqWDfoBozXN0xkohfCnD7erNZxf4qPRzNKD79WRzOgaHhBkoDwHIhhiqUFyWwNyFMSTYIZwlGFU4saG0VIfdKO_IhxIM5wF9Qs1zQvCaug1D7ppKK0gT7Q50ujIrrbtGqkNxVSWtg_vsbYniN_D2Scq-Z6Hozd8O7btRcOWTxfBJYRUAy-KbgiOw3_12uFoacyQssYHaYKnUN8tP93ubv9x83k_ZoZ4fXQxgt0RHZZPIBt9OL1iNNRK5ezYGB5sDe8y0rjkhKP1CHbij--orsn32Ww2bSN-KxMCW6yBU7OfLMyHlqB9ijlgNVAEaOPRjYtdzvhq2EPReIUNTsOz53VwuBINwmx20AHkDzA0lD9C69MurMJHyOp0oYRAjCKRFFjXaVLAPI6zJDnH7IeQnXTTavz8F0BZErMkhlk-bPMGxj1_HaduP-1uPq9vft398pnxXJtAYT8T60AAhsrW294ppHvadwLjS3ri5f7zwtb-p5vd5w-3H293-9Uvm78znr-weWlvsvO8Tz1vPGEKI22Ma2B8_twd2883N6u7DTCeMZ69nPt0s1vdbS6CKN421lvEz97v9_8L_19Z_b4IfFvwjQSkL888WLqSXdfoidqJgCaereyD8cGhbKGT6os84HtHGAcdootjjPFI5FmT05JE2LdMbHXFxCZFpYSsylKlqKpsnswLElR1XaDCtMakTISMiwXjRXRVXYuqEIW8wut5lmc5z9I8vTpe85zzFPOalzFiUeZJpmKBRaLypM6rVF3paxIOcTZP53Ga8TTCRZ1mMqnytMx5WmYsibGVuolI4xHoq0E8XWdC8PSqkSU2fjg84tzgw6SsOGfp5spdD7qw7A-eJXGjffDPVoIODY6HS6TZPa13be-bV2dEwQ7K-7Xmvupdc_2bdekAjoI9gP93AAAA__-HJw4T">