[libclc] [libclc] Add prepare-<triple> targets (PR #146700)

[Fraser Cormack via cfe-commits]

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@@ -356,55 +356,72 @@ function(add_libclc_builtin_set)
 
   set( builtins_link_lib $<TARGET_PROPERTY:${builtins_link_lib_tgt},TARGET_FILE> )
 
+  # For SPIR-V targets we diverage at this point and generate SPIR-V using the
+  # llvm-spirv tool.
   if( ARG_ARCH STREQUAL spirv OR ARG_ARCH STREQUAL spirv64 )
-    set( spv_suffix ${ARG_ARCH_SUFFIX}.spv )
-    add_custom_command( OUTPUT ${spv_suffix}
-      COMMAND ${llvm-spirv_exe} ${spvflags} -o ${spv_suffix} ${builtins_link_lib}
+    set( obj_suffix ${ARG_ARCH_SUFFIX}.spv )
+    add_custom_command( OUTPUT ${obj_suffix}
+      COMMAND ${llvm-spirv_exe} ${spvflags} -o ${obj_suffix} ${builtins_link_lib}
       DEPENDS ${llvm-spirv_target} ${builtins_link_lib} ${builtins_link_lib_tgt}
     )
-    add_custom_target( "prepare-${spv_suffix}" ALL DEPENDS "${spv_suffix}" )
-    set_target_properties( "prepare-${spv_suffix}" PROPERTIES FOLDER "libclc/Device IR/Prepare" )
-    install( FILES ${CMAKE_CURRENT_BINARY_DIR}/${spv_suffix}
-       DESTINATION "${CMAKE_INSTALL_DATADIR}/clc" )
-
-    return()
-  endif()
+  else()
+    # Non-SPIR-V targets add an extra step to optimize the bytecode
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frasercrmck wrote:

Yes I can look into that as a follow-up. Thanks for the idea.

I'd quite like to avoid using `opt` altogether, to be honest. I wonder if using liboffload's approach of using `clang` with LTO to create a bytecode library would solve this problem somewhat. I started looking into it but got pulled in other directions.

https://github.com/llvm/llvm-project/pull/146700