[llvm] [CMake][OCaml] Make OCaml bindings suitable for out-of-tree install (PR #123478)

[John Ericson via llvm-commits]

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@@ -38,12 +38,27 @@ function(add_ocaml_library name)
   set(ocaml_inputs)
 
   set(ocaml_outputs "${bin}/${name}.cma")
+
+  # The -custom flag causes bytecode executables to fail upon creating the
+  # runtime when installing the bindings for an out-of-tree build.
+  #
+  # However, the -custom flag is necessary when running the in-tree
+  # test suite, otherwise multiple libraries will link to the same libLLVM and
+  # runtime errors of the form
+  # "CommandLine Error: Option *opt* registered more than once!" will occur.
+  if (NOT LLVM_OCAML_OUT_OF_TREE AND NOT BUILD_SHARED_LIBS)
+    set(ocaml_custom TRUE)
+  else()
+    set(ocaml_custom FALSE)
+  endif()
+
   if( ARG_C )
+    # ocamlmklib outputs .a and .so
     list(APPEND ocaml_outputs
-         "${bin}/lib${name}${CMAKE_STATIC_LIBRARY_SUFFIX}")
-    if ( BUILD_SHARED_LIBS )
+         "${bin}/lib${name}.a")
+    if ( NOT ocaml_custom )
       list(APPEND ocaml_outputs
-           "${bin}/dll${name}${CMAKE_SHARED_LIBRARY_SUFFIX}")
+           "${bin}/dll${name}.so")
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Ericson2314 wrote:

Oh I see past talk on this, I still don't like this solution, however.

https://github.com/llvm/llvm-project/pull/123478