[NFC][libc] Remove unneeded gtest and benchmark configuration

[gchatelet]

Summary

The benchmarking infrastructure is now part of LLVM so we don't need to duplicate it anymore.

libc/benchmarks/CMakeLists.txt

 find_package(Threads)
 
-include(ExternalProject)
-
 set(LLVM_LINK_COMPONENTS Support)
 
 #==============================================================================
-# Build Google Benchmark
-#==============================================================================
-set(GOOGLE_BENCHMARK_TARGET_FLAGS ${BENCHMARK_DIALECT_FLAG})
-if (LIBCXX_BENCHMARK_GCC_TOOLCHAIN)
-  set(GOOGLE_BENCHMARK_TARGET_FLAGS
-      --gcc-toolchain=${LIBCXX_BENCHMARK_GCC_TOOLCHAIN})
-endif()
-string(REPLACE ";" " " GOOGLE_BENCHMARK_TARGET_FLAGS "${GOOGLE_BENCHMARK_TARGET_FLAGS}")
-
-ExternalProject_Add(google-benchmark
-    EXCLUDE_FROM_ALL ON
-    PREFIX google-benchmark
-    SOURCE_DIR ${LLVM_THIRD_PARTY_DIR}/benchmark
-    INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark
-    CMAKE_CACHE_ARGS
-        -DBUILD_SHARED_LIBS:BOOL=OFF
-        -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
-        -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
-        -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
-        -DCMAKE_CXX_FLAGS:STRING=${GOOGLE_BENCHMARK_TARGET_FLAGS}
-        -DCMAKE_CXX_STANDARD:STRING=14
-        -DCMAKE_BUILD_TYPE:STRING=RELEASE
-        -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
-        -DBENCHMARK_ENABLE_TESTING:BOOL=OFF)
-
-set(GOOGLE_BENCHMARK_LIBC_INSTALL ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark)
-set(GOOGLE_BENCHMARK_LINK_FLAGS    -L${GOOGLE_BENCHMARK_LIBC_INSTALL}/lib/)
-
-#==============================================================================
 # Add Unit Testing Support
 #==============================================================================
 
 function(add_libc_benchmark_unittest target_name)
   if(NOT LLVM_INCLUDE_TESTS)
     return()
   endif()
 

 endfunction()
 
 #==============================================================================
 # Build Google Benchmark for libc
 #==============================================================================
 
 add_custom_target(libc-benchmark-util-tests)
 
-function(fix_rtti target)
-    # TODO: Make this portable and inline with rtti mode from llvm/
-    target_compile_options(${target} PUBLIC -fno-rtti)
-endfunction()
-
 # libc-benchmark
 add_library(libc-benchmark
     STATIC
     EXCLUDE_FROM_ALL
     LibcBenchmark.cpp
     LibcBenchmark.h
 )
-add_dependencies(libc-benchmark google-benchmark)
-target_include_directories(libc-benchmark
-    SYSTEM PUBLIC
-    "${GOOGLE_BENCHMARK_LIBC_INSTALL}/include"
-)
+add_dependencies(libc-benchmark benchmark)
 target_link_libraries(libc-benchmark
     PUBLIC
-    "${GOOGLE_BENCHMARK_LINK_FLAGS}" # FIXME: Move to `target_link_options`
-    -lbenchmark                      # FIXME: Move to `target_link_options`
+    benchmark
     LLVMSupport
     Threads::Threads
 )
-fix_rtti(libc-benchmark)
 
 add_libc_benchmark_unittest(libc-benchmark-test
     SRCS LibcBenchmarkTest.cpp
     DEPENDS libc-benchmark
 )
 
 # libc-memory-benchmark
 add_library(libc-memory-benchmark
     STATIC
     EXCLUDE_FROM_ALL
     LibcMemoryBenchmark.cpp
     LibcMemoryBenchmark.h
     LibcFunctionPrototypes.h
     MemorySizeDistributions.cpp
     MemorySizeDistributions.h
 )
 target_include_directories(libc-memory-benchmark
     PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
 )
 target_link_libraries(libc-memory-benchmark
     PUBLIC
     libc-benchmark
 )
-fix_rtti(libc-memory-benchmark)
 
 add_libc_benchmark_unittest(libc-memory-benchmark-test
     SRCS LibcMemoryBenchmarkTest.cpp
     DEPENDS libc-memory-benchmark
 )
 
 # json
 add_library(json
     STATIC
     EXCLUDE_FROM_ALL
     JSON.cpp
     JSON.h
 )
 target_link_libraries(json PUBLIC libc-memory-benchmark)
-fix_rtti(json)
 
 add_libc_benchmark_unittest(json-test
     SRCS JSONTest.cpp
     DEPENDS json
 )
 
 #==============================================================================
 # Benchmarking tool