compiler-rt

// pass build on linux but generate x86_64, not cpu0
git apply compiler-rt.patch
~/llvm/llvm-project/build-compiler-rt$ cmake ../compiler-rt -DLLVM_CONFIG_PATH=/home/jonathanchen/llvm/test/build/bin/llvm-config -DCOMPILER_RT_USE_LIBCXX=OFF
~/llvm/llvm-project/build-compiler-rt$ make -j4
~/llvm/llvm-project/build-compiler-rt$ ls lib/linux/
ibclang_rt.builtins-cpu0.a         libclang_rt.hwasan_cxx-x86_64.a.syms      libclang_rt.scudo_cxx-x86_64.a             libclang_rt.ubsan_standalone-x86_64.a.syms
libclang_rt.builtins-x86_64.a 


jonathanchen@hz-compiler1:/local/git/ex/c++/3$ /local/git/llvm-project/build_all_libcxx/bin/clang++ main.cpp --rtlib=compiler-rt -v
...
 "/usr/bin/ld" ... -lm /local/git/llvm-project/build_all_libcxx/lib/clang/13.0.1/lib/linux/libclang_rt.builtins-x86_64.a -lc /local/git/llvm-project/build_all_libcxx/lib/clang/13.0.1/lib/linux/libclang_rt.builtins-x86_64.a ...


compiler-rt/cmake/builtin-config-ix.cmake
 set(MIPS64 mips64 mips64el)
+set(CPU0 cpu0)


compiler-rt/lib/builtins/CMakeLists.txt
@@ -511,6 +511,10 @@ set(aarch64_SOURCES
   aarch64/fp_mode.c
 )
 
+set(cpu0_SOURCES
+  ${GENERIC_SOURCES}
+)
+

   darwin_add_builtin_libraries(${BUILTIN_SUPPORTED_OS})
+  
+  set(type "STATIC")
+  if(type STREQUAL "STATIC")
+    set(libname "clang_rt.builtins-${CPU0}")
+  else()
+    message(FATAL_ERROR "${CPU0} supports static link only")
+  endif()
+  set(sources_${libname} ${LIB_SOURCES})
+  get_compiler_rt_output_dir(${CPU0} output_dir_${libname})
+  get_compiler_rt_install_dir(${CPU0} install_dir_${libname})
+  add_library(${libname} ${type} ${sources_${libname}})
+  set(extra_cflags_${libname} ${NO_LTO_FLAGS} ${NO_PGO_FLAGS} ${LIB_CFLAGS})