[AIX] Disable $ORIGIN rpath

[daltenty]

Summary

The AIX loader doesn't support relative libpaths, so this mechanism
doesn't work and just messes up the resulting libpath. Also make sure
BUILD_WITH_INSTALL_RPATH is set, since we can't change the rpath on
install.

[DiggerLin]

llvm/cmake/modules/AddLLVM.cmake

2112

in the following

1. Enable BUILD_WITH_INSTALL_RPATH unless CMAKE_BUILD_RPATH is set. if("${CMAKE_BUILD_RPATH}" STREQUAL "") set_property(TARGET ${name} PROPERTY BUILD_WITH_INSTALL_RPATH ON) endif()

we enable the PROPERTY BUILD_WITH_INSTALL_RPATH anyway?

https://reviews.llvm.org/D93177 [CMake] Don't enable BUILD_WITH_INSTALL_RPATH when using custom build rpath

llvm/cmake/modules/AddLLVM.cmake

if(LLVM_INSTALL_PREFIX AND NOT (LLVM_INSTALL_PREFIX STREQUAL CMAKE_INSTALL_PREFIX))
     set(extra_libdir ${LLVM_LIBRARY_DIR})
   elseif(LLVM_BUILD_LIBRARY_DIR)
     set(extra_libdir ${LLVM_LIBRARY_DIR})
   endif()
 
   if (APPLE)
     set(_install_name_dir INSTALL_NAME_DIR "@rpath")
     set(_install_rpath "@loader_path/../lib${LLVM_LIBDIR_SUFFIX}" ${extra_libdir})
+  elseif(${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+    # $ORIGIN isn't supported by the AIX loader. Also, their isn't support for
+    # required for different build/install rpaths in some of the build tools.
+    set_property(TARGET ${name} PROPERTY BUILD_WITH_INSTALL_RPATH ON)
+    return()
   elseif(UNIX)
     set(_install_rpath "\$ORIGIN/../lib${LLVM_LIBDIR_SUFFIX}" ${extra_libdir})
     if(${CMAKE_SYSTEM_NAME} MATCHES "(FreeBSD|DragonFly)")
       set_property(TARGET ${name} APPEND_STRING PROPERTY
                    LINK_FLAGS " -Wl,-z,origin ")
     endif()
     if(LLVM_LINKER_IS_GNULD)
       # $ORIGIN is not interpreted at link time by ld.bfd