<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/85504>85504</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [CMake] LLVM_HOST_TRIPLE cross compilation ignores CMAKE_SHARED_LINKER_FLAGS
        </td>
    </tr>

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

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

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

<pre>
    I am trying a cross compilation (`-DLLVM_HOST_TRIPLE=x86_64-linux-musl`). It seems that shared object links (e.g. `lib/LLVMHello.so`, `unittests/Support/DynamicLibrary/PipSqueak.so`) do not respect `CMAKE_SHARED_LINKER_FLAGS`.

If I use `LLVM_USE_SPLIT_DWARF=on`, a DSO link does not pick up `-fuse-ld=lld` and will fail due to GNU ld not supporting `--gdb-index`

```sh
MUSL=$HOME/Dev/musl-cross-make
cmake -GNinja -Sllvm -B/tmp/out/musl -DCMAKE_BUILD_TYPE=Debug -DLLVM_USE_SPLIT_DWARF=on -DCMAKE_C_COMPILER=~/Stable/bin/clang -DCMAKE_CXX_COMPILER=~/Stable/bin/clang++ -DCMAKE_{C,CXX}_FLAGS="--target=x86_64-linux-musl --sysroot=$MUSL/output/x86_64-linux-musl --gcc-install-dir=$MUSL/output/lib/gcc/x86_64-linux-musl/9.4.0" -DCMAKE_{EXE,SHARED}_LINKER_FLAGS="-fuse-ld=lld -Wl,--dynamic-linker=$MUSL/output/x86_64-linux-musl/lib/libc.so -Wl,-rpath=$MUSL/output/x86_64-linux-musl/lib" -DLLVM_NATIVE_TOOL_DIR=/tmp/Rel/bin -DLLVM_HOST_TRIPLE=x86_64-linux-musl -DLLVM_TARGETS_TO_BUILD=host -DLLVM_ENABLE_PROJECTS='clang;lld'
```
</pre>
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