…#23574)

When building `libIREECompiler.so` in `TheRock` I hit the following
error when trying to load the library:

```
LLVM ERROR: Option 'pbqp' already exists!
```

I'll put the full claude generated description of what happened below
but the long and the short of it is `libIREECompiler.so` seems to be
exporting quite a few symbols when linking LLVM's static `.a`'s. In my
case, `TheRock` has another library that loads `libLLVM.so`, and when
loaded it
[interposes](https://maskray.me/blog/2021-05-16-elf-interposition-and-bsymbolic)
some of the global command line registration machinery. Because of the
interposition, `libIREECompiler.so`'s command line registration got
routed to `libLLVM.so`'s; luckily, rather than some incredibly hard to
diagnose error, the double command line registration crashes on startup.

`--exclude-libs,ALL` hides symbols from static libraries when linking
the final `libIREECompiler.so`, preventing LLVM's symbols from being
exported and therefore being interposable.

---

Claude generated description

```
Add --exclude-libs=ALL to libIREECompiler.so shared library
libIREECompiler.so statically links LLVM/MLIR but exports ~175K internal
symbols via its version script (api_version.ld uses `global: *`). The
visibility design assumes LLVM is compiled with -fvisibility=hidden, but
LLVM's own CMake build only applies -fvisibility-inlines-hidden — not
-fvisibility=hidden — to the vast majority of its compilation units
(2250/2720 LLVM files, 1049/1145 MLIR files lack the flag). This means
all non-inline LLVM symbols default to visibility("default") and leak
through the version script.

When libIREECompiler.so is loaded via dlopen(RTLD_LOCAL) into a process
that already has libLLVM.so in the global scope (e.g. via HIP runtime's
libamd_comgr.so → libLLVM.so.22.0git), the ELF dynamic linker searches
the global scope first when resolving relocations. LLVM function calls
in libIREECompiler.so that go through the PLT/GOT resolve to
libLLVM.so's copies rather than the compiler's own static LLVM. This
causes LLVM cl::Option static initializers to register duplicate options
into libLLVM.so's global registry, crashing with:

  LLVM ERROR: Option 'pbqp' already exists!

The fix adds --exclude-libs=ALL to the SharedImpl linker options, which
forces all symbols from static archives (.a files) to hidden visibility
at link time. Only symbols from object files (.o) compiled with explicit
__attribute__((visibility("default"))) annotations — i.e. the IREE and
MLIR C API functions marked with IREE_EMBED_EXPORTED / MLIR_CAPI_EXPORTED
— remain visible. This reduces exported dynamic symbols from ~274K to
~2.9K.

This matches the pattern already used by MLIR's own MLIR-C shared
library (mlir/lib/CAPI/CMakeLists.txt):

  target_link_options(MLIR-C PRIVATE "-Wl,-exclude-libs,ALL")
  ```
  
ci-extra: all

---------

Signed-off-by: Bangtian Liu <[email protected]>
Co-authored-by: Claude Opus 4.6 <[email protected]>
Co-authored-by: Bangtian Liu <[email protected]>