[SYCL][libclc] Fix cross builds (#16244)

When performing cross builds, we need native versions of various tools,
we cannot assume the cross builds that are part of the current build are
executable. LLVM provides the setup_host_tool function to handle this,
either picking up versions of tools from LLVM_NATIVE_TOOL_DIR, or
implicitly building native versions as needed. Use this in more places.

This applies the changes from LLVM #97392 and #97811 and adapts them to
DPC++, and makes the same changes in other places that are only needed
for DPC++.

Tested with a suitable cross compilation toolchain file:
```console
$ mkdir build
$ cat >build/aarch64-linux.cmake <<EOF
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR aarch64)

set(CMAKE_C_COMPILER "aarch64-linux-gnu-gcc" CACHE STRING "")
set(CMAKE_CXX_COMPILER "aarch64-linux-gnu-g++" CACHE STRING "")
set(PKG_CONFIG_EXECUTABLE "aarch64-linux-gnu-pkg-config" CACHE STRING "")

set(CMAKE_FIND_ROOT_PATH /usr/aarch64-linux-gnu)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
EOF
$ python3 buildbot/configure.py -o build/aarch64-linux    \
  --cmake-opt=--toolchain=$PWD/build/aarch64-linux.cmake  \
  --cmake-opt=-DLLVM_HOST_TRIPLE=aarch64-unknown-linux-gnu
```

Author: hvdijk

clang/tools/clang-offload-bundler/CMakeLists.txt

@@ -18,6 +18,9 @@ add_clang_tool(clang-offload-bundler
   intrinsics_gen
   )
 
+setup_host_tool(clang-offload-bundler CLANG_OFFLOAD_BUNDLER
+  clang-offload-bundler_exe clang-offload-bundler_target)
+
 set(CLANG_OFFLOAD_BUNDLER_LIB_DEPS
   clangBasic
   clangDriver

clang/tools/clang-offload-packager/CMakeLists.txt

@@ -12,6 +12,9 @@ add_clang_tool(clang-offload-packager
   ${tablegen_deps}
   )
 
+setup_host_tool(clang-offload-packager CLANG_OFFLOAD_PACKAGER_EXE
+  clang-offload-packager_exe clang-offload-packager_target)
+
 clang_target_link_libraries(clang-offload-packager
   PRIVATE
   clangBasic

libclc/CMakeLists.txt

@@ -70,7 +70,7 @@ if( LIBCLC_STANDALONE_BUILD OR CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DI
 
   # Import required tools
   if( NOT EXISTS ${LIBCLC_CUSTOM_LLVM_TOOLS_BINARY_DIR} )
-    foreach( tool IN ITEMS clang llvm-as llvm-link opt )
+    foreach( tool IN ITEMS clang llvm-as llvm-link llvm-spirv opt )
       find_program( LLVM_TOOL_${tool} ${tool} PATHS ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH )
       set( ${tool}_exe ${LLVM_TOOL_${tool}} )
       set( ${tool}_target )
@@ -93,6 +93,7 @@ else()
     get_host_tool_path( clang CLANG clang_exe clang_target )
     get_host_tool_path( llvm-as LLVM_AS llvm-as_exe llvm-as_target )
     get_host_tool_path( llvm-link LLVM_LINK llvm-link_exe llvm-link_target )
+    get_host_tool_path( llvm-spirv LLVM_SPIRV llvm-spirv_exe llvm-spirv_target )
     get_host_tool_path( opt OPT opt_exe opt_target )
   endif()
 endif()
@@ -114,13 +115,15 @@ if( EXISTS ${LIBCLC_CUSTOM_LLVM_TOOLS_BINARY_DIR} )
 
   # If we've requested a custom binary directory, there are some otherwise
   # optional tools which we want to ensure are present.
-  if( NOT TARGET libclc::llvm-spirv OR NOT TARGET libclc::libclc-remangler )
-    message( FATAL_ERROR "libclc toolchain incomplete!" )
-  endif()
+  foreach( tool IN ITEMS llvm-spirv libclc-remangler )
+    if( NOT EXISTS "${${tool}_exe}" AND "${${tool}_target}" STREQUAL "" )
+      message( FATAL_ERROR "libclc toolchain incomplete!" )
+    endif()
+  endforeach()
 endif()
 
 foreach( tool IN ITEMS clang opt llvm-as llvm-link )
-  if( NOT EXISTS "${${tool}_exe}" AND "${tool}_target" STREQUAL "" )
+  if( NOT EXISTS "${${tool}_exe}" AND "${${tool}_target}" STREQUAL "" )
     message( FATAL_ERROR "libclc toolchain incomplete - missing tool ${tool}!" )
   endif()
 endforeach()

libclc/cmake/modules/AddLibclc.cmake

@@ -456,13 +456,13 @@ function(add_libclc_builtin_set)
             "${LIBCLC_LIBRARY_OUTPUT_INTDIR}/remangled-${long_width}-${signedness}_char.${obj_suffix_mangled}" )
         add_custom_command( OUTPUT "${builtins_remangle_path}"
           COMMAND ${CMAKE_COMMAND} -E make_directory ${LIBCLC_LIBRARY_OUTPUT_INTDIR}
-          COMMAND libclc::libclc-remangler
+          COMMAND ${libclc-remangler_exe}
           -o "${builtins_remangle_path}"
           --long-width=${long_width}
           --char-signedness=${signedness}
           --input-ir=${builtins_lib}
           ${dummy_in}
-          DEPENDS ${builtins_lib} libclc::libclc-remangler ${dummy_in})
+          DEPENDS ${builtins_lib} ${libclc-remangler_target} ${dummy_in})
         add_custom_target( "remangled-${long_width}-${signedness}_char.${obj_suffix_mangled}" ALL
           DEPENDS "${builtins_remangle_path}" "${dummy_in}")
         set_target_properties("remangled-${long_width}-${signedness}_char.${obj_suffix_mangled}"
@@ -489,12 +489,12 @@ function(add_libclc_builtin_set)
       math(EXPR libclc-remangler-test-no "${libclc-remangler-test-no}+1")
       set(current-test "libclc-remangler-test-${obj_suffix}-${libclc-remangler-test-no}")
       add_custom_target(${current-test}
-        COMMAND libclc::libclc-remangler
+        COMMAND ${libclc-remangler_exe}
         --long-width=l32
         --char-signedness=signed
         --input-ir=${target-ir}
         ${dummy_in} -t -o -
-        DEPENDS ${builtins_lib} "${dummy_in}" libclc::libclc-remangler)
+        DEPENDS ${builtins_lib} "${dummy_in}" ${libclc-remangler_target})
       list(APPEND libclc-remangler-tests ${current-test})
     endforeach()
   endif()

libclc/utils/libclc-remangler/CMakeLists.txt

@@ -11,6 +11,9 @@ set(LLVM_LINK_COMPONENTS
 
 add_clang_tool(libclc-remangler LibclcRemangler.cpp)
 
+setup_host_tool( libclc-remangler LIBCLC_REMANGLER
+  libclc-remangler_exe libclc-remangler_target )
+
 target_include_directories(libclc-remangler PRIVATE
   ${CMAKE_SOURCE_DIR}/../clang/include
   ${CMAKE_BINARY_DIR}/tools/clang/include)
@@ -24,9 +27,3 @@ clang_target_link_libraries(libclc-remangler
   clangSerialization
   LLVMOption
   )
-
-# If we've not already imported a libclc-remangler tool from an external build,
-# set it up now.
-if(NOT TARGET libclc::libclc-remangler)
-  add_executable(libclc::libclc-remangler ALIAS libclc-remangler)
-endif()

libdevice/CMakeLists.txt

@@ -19,6 +19,25 @@ else()
                    will not build libdevice sanitizer")
 endif()
 
+if(NOT EXISTS ${LIBCLC_CUSTOM_LLVM_TOOLS_BINARY_DIR})
+  get_host_tool_path(clang CLANG clang_exe clang_target)
+  get_host_tool_path(llvm-ar LLVM_AR llvm-ar_exe llvm-ar_target)
+  get_host_tool_path(append-file APPEND_FILE append-file_exe append-file_target)
+  get_host_tool_path(clang-offload-bundler CLANG_OFFLOAD_BUNDLER clang-offload-bundler_exe clang-offload-bundler_target)
+  get_host_tool_path(clang-offload-packager CLANG_OFFLOAD_PACKAGER clang-offload-packager_exe clang-offload-packager_target)
+  get_host_tool_path(file-table-tform FILE_TABLE_TFORM file-table-tform_exe file-table-tform_target)
+  get_host_tool_path(llvm-foreach LLVM_FOREACH llvm-foreach_exe llvm-foreach_target)
+  get_host_tool_path(llvm-spirv LLVM_SPIRV llvm-spirv_exe llvm-spirv_target)
+  get_host_tool_path(sycl-post-link SYCL_POST_LINK sycl-post-link_exe sycl-post-link_target)
+else()
+  foreach(tool IN ITEMS clang llvm-ar append-file clang-offload-bundler clang-offload-packager file-table-tform llvm-foreach llvm-spirv sycl-post-link)
+    find_program(LLVM_CUSTOM_TOOL_${tool} ${tool}
+      PATHS ${LIBCLC_CUSTOM_LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH)
+    set(${tool}_exe ${LLVM_CUSTOM_TOOL_${tool}})
+    set(${tool}_target)
+  endforeach()
+endif()
+
 # Build libdevice for SYCL.
 include(SYCLLibdevice)
 

libdevice/cmake/modules/SYCLLibdevice.cmake

@@ -22,11 +22,6 @@ set(install_dest_obj lib${LLVM_LIBDIR_SUFFIX})
 set(install_dest_obj-new-offload lib${LLVM_LIBDIR_SUFFIX})
 set(install_dest_bc lib${LLVM_LIBDIR_SUFFIX})
 
-set(clang $<TARGET_FILE:clang>)
-set(llvm-ar $<TARGET_FILE:llvm-ar>)
-set(llvm-link $<TARGET_FILE:llvm-link>)
-set(llvm-opt $<TARGET_FILE:opt>)
-
 string(CONCAT sycl_targets_opt
   "-fsycl-targets="
   "spir64_x86_64-unknown-unknown,"
@@ -55,6 +50,7 @@ set(compile_opts
   # we declare all functions as 'static'.
   -Wno-undefined-internal
   -sycl-std=2020
+  --target=${LLVM_HOST_TRIPLE}
   )
 
 set(SYCL_LIBDEVICE_GCC_TOOLCHAIN "" CACHE PATH "Path to GCC installation")
@@ -146,7 +142,8 @@ function(compile_lib_ext filename)
 
   add_custom_command(
     OUTPUT ${devicelib-file}
-    COMMAND ${clang} ${ARG_OPTS}
+    COMMAND ${clang_exe} -I ${PROJECT_BINARY_DIR}/include
+            ${ARG_OPTS}
             ${CMAKE_CURRENT_SOURCE_DIR}/${ARG_SRC} -o ${devicelib-file}
     MAIN_DEPENDENCY ${ARG_SRC}
     DEPENDS ${ARG_DEPENDENCIES}
@@ -224,20 +221,26 @@ function(add_devicelibs filename)
   endforeach()
 endfunction()
 
-# Set up the dependency lists for the libdevice libraries
-set(crt_obj_deps wrapper.h device.h spirv_vars.h sycl-compiler)
-set(complex_obj_deps device_complex.h device.h sycl-compiler)
-set(cmath_obj_deps device_math.h device.h sycl-compiler)
-set(imf_obj_deps device_imf.hpp imf_half.hpp imf_bf16.hpp imf_rounding_op.hpp imf_impl_utils.hpp device.h sycl-compiler)
-set(itt_obj_deps device_itt.h spirv_vars.h device.h sycl-compiler)
-set(bfloat16_obj_deps sycl-headers sycl-compiler)
+# For native builds, sycl-compiler will already include everything we need.
+# For cross builds, we also need native versions of the tools.
+set(sycl-compiler_deps
+  sycl-compiler ${clang_target} ${append-file_target}
+  ${clang-offload-bundler_target} ${clang-offload-packager_target}
+  ${file-table-tform_target} ${llvm-foreach_target} ${llvm-spirv_target}
+  ${sycl-post-link_target})
+set(crt_obj_deps wrapper.h device.h spirv_vars.h ${sycl-compiler_deps})
+set(complex_obj_deps device_complex.h device.h ${sycl-compiler_deps})
+set(cmath_obj_deps device_math.h device.h ${sycl-compiler_deps})
+set(imf_obj_deps device_imf.hpp imf_half.hpp imf_bf16.hpp imf_rounding_op.hpp imf_impl_utils.hpp device.h ${sycl-compiler_deps})
+set(itt_obj_deps device_itt.h spirv_vars.h device.h ${sycl-compiler_deps})
+set(bfloat16_obj_deps sycl-headers ${sycl-compiler_deps})
 if (NOT MSVC AND UR_SANITIZER_INCLUDE_DIR)
   set(asan_obj_deps
     device.h atomic.hpp spirv_vars.h
     ${UR_SANITIZER_INCLUDE_DIR}/asan/asan_libdevice.hpp
     include/asan_rtl.hpp
     include/spir_global_var.hpp
-    sycl-compiler)
+    ${sycl-compiler_deps})
 
   set(sanitizer_generic_compile_opts ${compile_opts}
                             -fno-sycl-instrument-device-code
@@ -442,6 +445,7 @@ set(imf_fp64_fallback_src ${imf_fallback_src_dir}/imf_fp64_fallback.cpp)
 set(imf_bf16_fallback_src ${imf_fallback_src_dir}/imf_bf16_fallback.cpp)
 
 set(imf_host_cxx_flags -c
+  --target=${LLVM_HOST_TRIPLE}
   -D__LIBDEVICE_HOST_IMPL__
 )
 
@@ -535,13 +539,13 @@ function(add_lib_imf name)
 
   add_custom_command(
     OUTPUT ${ARG_DIR}/${name}.${${ARG_FTYPE}-suffix}
-    COMMAND ${clang} ${compile_opts} ${ARG_EXTRA_OPTS}
+    COMMAND ${clang_exe} ${compile_opts} ${ARG_EXTRA_OPTS}
             -I ${CMAKE_CURRENT_SOURCE_DIR}/imf
             ${imf_${ARG_DTYPE}_fallback_src}
             -o
             ${ARG_DIR}/${name}.${${ARG_FTYPE}-suffix}
             DEPENDS ${imf_fallback_${ARG_DTYPE}_deps}
-            get_imf_fallback_${ARG_DTYPE} sycl-compiler
+            get_imf_fallback_${ARG_DTYPE} ${sycl-compiler_deps}
     VERBATIM)
 
   add_custom_target(${ARG_TGT_NAME}
@@ -635,7 +639,7 @@ foreach(dtype IN ITEMS bf16 fp32 fp64)
     endif()
     add_custom_command(
       OUTPUT ${${ftype}_binary_dir}/imf-${dtype}-host.${${ftype}-suffix}
-      COMMAND ${clang} ${${ftype}_host_compile_opts}
+      COMMAND ${clang_exe} ${${ftype}_host_compile_opts}
               ${CMAKE_CURRENT_SOURCE_DIR}/${wrapper_name}
               -o ${${ftype}_binary_dir}/imf-${dtype}-host.${${ftype}-suffix}
       MAIN_DEPENDENCY ${CMAKE_CURRENT_SOURCE_DIR}/${wrapper_name}
@@ -652,7 +656,7 @@ foreach(ftype IN ITEMS obj obj-new-offload)
     DEPENDS ${${ftype}_binary_dir}/${devicelib_host_static_${ftype}})
   add_custom_command(
     OUTPUT ${${ftype}_binary_dir}/${devicelib_host_static_${ftype}}
-    COMMAND ${llvm-ar} rcs
+    COMMAND ${llvm-ar_exe} rcs
             ${${ftype}_binary_dir}/${devicelib_host_static_${ftype}}
             ${${ftype}_binary_dir}/imf-fp32-host.${${ftype}-suffix}
             ${${ftype}_binary_dir}/fallback-imf-fp32-host.${${ftype}-suffix}
@@ -663,7 +667,7 @@ foreach(ftype IN ITEMS obj obj-new-offload)
     DEPENDS imf_fp32_host_${ftype} imf_fallback_fp32_host_${ftype}
     DEPENDS imf_fp64_host_${ftype} imf_fallback_fp64_host_${ftype}
     DEPENDS imf_bf16_host_${ftype} imf_fallback_bf16_host_${ftype}
-    DEPENDS sycl-compiler
+    DEPENDS ${llvm-ar_target}
     VERBATIM)
   add_dependencies(libsycldevice-obj imf_host_${ftype})
 

llvm/tools/append-file/CMakeLists.txt

@@ -9,3 +9,5 @@ add_llvm_tool(append-file
   DEPENDS
   intrinsics_gen
   )
+
+setup_host_tool(append-file APPEND_FILE append_file_exe append_file_target)

llvm/tools/file-table-tform/CMakeLists.txt

@@ -5,3 +5,5 @@ set(LLVM_LINK_COMPONENTS
 add_llvm_tool(file-table-tform
   file-table-tform.cpp
   )
+
+setup_host_tool(file-table-tform FILE_TABLE_TFORM file-table-tform_exe file-table-tform_target)

llvm/tools/llvm-ar/CMakeLists.txt

@@ -19,6 +19,8 @@ add_llvm_tool(llvm-ar
   GENERATE_DRIVER
   )
 
+setup_host_tool(llvm-ar LLVM_AR llvm_ar_exe llvm_ar_target)
+
 add_llvm_tool_symlink(llvm-ranlib llvm-ar)
 add_llvm_tool_symlink(llvm-lib llvm-ar)
 add_llvm_tool_symlink(llvm-dlltool llvm-ar)