[libc][test] make str_to_float_comparison_test independent of C++ headers. (llvm#133978)

This is an attempt to move away from C++ headers to be able to run the
test without `libcxx`.
closes llvm#129838

cc @lntue @RossComputerGuy

Author: bassiounix

libc/cmake/modules/LLVMLibCTestRules.cmake

@@ -191,6 +191,7 @@ endfunction(get_object_files_for_test)
 #      SRCS  <list of .cpp files for the test>
 #      HDRS  <list of .h files for the test>
 #      DEPENDS <list of dependencies>
+#      ENV <list of environment variables to set before running the test>
 #      COMPILE_OPTIONS <list of special compile options for this target>
 #      LINK_LIBRARIES <list of linking libraries for this target>
 #    )
@@ -203,7 +204,7 @@ function(create_libc_unittest fq_target_name)
     "LIBC_UNITTEST"
     "NO_RUN_POSTBUILD;C_TEST" # Optional arguments
     "SUITE;CXX_STANDARD" # Single value arguments
-    "SRCS;HDRS;DEPENDS;COMPILE_OPTIONS;LINK_LIBRARIES;FLAGS" # Multi-value arguments
+    "SRCS;HDRS;DEPENDS;ENV;COMPILE_OPTIONS;LINK_LIBRARIES;FLAGS" # Multi-value arguments
     ${ARGN}
   )
   if(NOT LIBC_UNITTEST_SRCS)
@@ -319,7 +320,7 @@ function(create_libc_unittest fq_target_name)
   if(NOT LIBC_UNITTEST_NO_RUN_POSTBUILD)
     add_custom_target(
       ${fq_target_name}
-      COMMAND ${fq_build_target_name}
+      COMMAND ${LIBC_UNITTEST_ENV} ${CMAKE_CROSSCOMPILING_EMULATOR} ${fq_build_target_name}
       COMMENT "Running unit test ${fq_target_name}"
     )
   endif()
@@ -642,7 +643,7 @@ function(add_libc_hermetic test_name)
   endif()
   cmake_parse_arguments(
     "HERMETIC_TEST"
-    "IS_GPU_BENCHMARK" # Optional arguments
+    "IS_GPU_BENCHMARK;NO_RUN_POSTBUILD" # Optional arguments
     "SUITE;CXX_STANDARD" # Single value arguments
     "SRCS;HDRS;DEPENDS;ARGS;ENV;COMPILE_OPTIONS;LINK_LIBRARIES;LOADER_ARGS" # Multi-value arguments
     ${ARGN}
@@ -713,7 +714,12 @@ function(add_libc_hermetic test_name)
   set_target_properties(${fq_target_name}.__libc__
       PROPERTIES ARCHIVE_OUTPUT_NAME ${fq_target_name}.libc)
 
-  set(fq_build_target_name ${fq_target_name}.__build__)
+  if(HERMETIC_TEST_NO_RUN_POSTBUILD)
+    set(fq_build_target_name ${fq_target_name})
+  else()
+    set(fq_build_target_name ${fq_target_name}.__build__)
+  endif()
+
   add_executable(
     ${fq_build_target_name}
     EXCLUDE_FROM_ALL
@@ -794,26 +800,28 @@ function(add_libc_hermetic test_name)
     get_target_property(gpu_loader_exe libc.utils.gpu.loader "EXECUTABLE")
   endif()
 
-  set(test_cmd ${HERMETIC_TEST_ENV}
-      $<$<BOOL:${LIBC_TARGET_OS_IS_GPU}>:${gpu_loader_exe}> ${CMAKE_CROSSCOMPILING_EMULATOR} ${HERMETIC_TEST_LOADER_ARGS}
-      $<TARGET_FILE:${fq_build_target_name}> ${HERMETIC_TEST_ARGS})
-  add_custom_target(
-    ${fq_target_name}
-    DEPENDS ${fq_target_name}-cmd
-  )
+  if(NOT HERMETIC_TEST_NO_RUN_POSTBUILD)
+    set(test_cmd ${HERMETIC_TEST_ENV}
+        $<$<BOOL:${LIBC_TARGET_OS_IS_GPU}>:${gpu_loader_exe}> ${CMAKE_CROSSCOMPILING_EMULATOR} ${HERMETIC_TEST_LOADER_ARGS}
+        $<TARGET_FILE:${fq_build_target_name}> ${HERMETIC_TEST_ARGS})
+    add_custom_target(
+      ${fq_target_name}
+      DEPENDS ${fq_target_name}.__cmd__
+    )
 
-  add_custom_command(
-    OUTPUT ${fq_target_name}-cmd
-    COMMAND ${test_cmd}
-    COMMAND_EXPAND_LISTS
-    COMMENT "Running hermetic test ${fq_target_name}"
-    ${LIBC_HERMETIC_TEST_JOB_POOL}
-  )
+    add_custom_command(
+      OUTPUT ${fq_target_name}.__cmd__
+      COMMAND ${test_cmd}
+      COMMAND_EXPAND_LISTS
+      COMMENT "Running hermetic test ${fq_target_name}"
+      ${LIBC_HERMETIC_TEST_JOB_POOL}
+    )
 
-  set_source_files_properties(${fq_target_name}-cmd
-    PROPERTIES
-      SYMBOLIC "TRUE"
-  )
+    set_source_files_properties(${fq_target_name}.__cmd__
+      PROPERTIES
+        SYMBOLIC "TRUE"
+    )
+  endif()
 
   add_dependencies(${HERMETIC_TEST_SUITE} ${fq_target_name})
   if(NOT ${HERMETIC_TEST_IS_GPU_BENCHMARK})

libc/test/src/__support/CMakeLists.txt

@@ -249,32 +249,25 @@ add_libc_test(
     libc.src.__support.memory_size
 )
 
-# FIXME: We shouldn't have regular executables created because we could be
-#        cross-compiling the tests and running through an emulator.
-if(NOT LIBC_TARGET_OS_IS_GPU)
-  add_executable(
-    libc_str_to_float_comparison_test
-    str_to_float_comparison_test.cpp
-  )
-
-  target_link_libraries(libc_str_to_float_comparison_test
-    PRIVATE
-      "${LIBC_TARGET}"
-  )
-
-  add_executable(
-    libc_system_str_to_float_comparison_test
+add_libc_test(
+  str_to_float_comparison_test
+  NO_RUN_POSTBUILD
+  SUITE
+    libc-support-tests
+  SRCS
     str_to_float_comparison_test.cpp
-  )
-
-  set(float_test_file ${CMAKE_CURRENT_SOURCE_DIR}/str_to_float_comparison_data.txt)
-
-  add_custom_command(TARGET libc_str_to_float_comparison_test
-                     POST_BUILD
-                     COMMAND ${CMAKE_CROSSCOMPILING_EMULATOR} $<TARGET_FILE:libc_str_to_float_comparison_test> ${float_test_file}
-                     COMMENT "Test the strtof and strtod implementations against precomputed results."
-                     VERBATIM)
-endif()
+  DEPENDS
+    libc.src.stdio.printf
+    libc.src.stdio.fopen
+    libc.src.stdio.fclose
+    libc.src.stdio.fgets
+    libc.src.stdlib.strtof
+    libc.src.stdlib.strtod
+    libc.src.stdlib.getenv
+    libc.src.string.strtok
+    libc.src.string.strdup
+    libc.src.__support.CPP.bit
+)
 
 add_subdirectory(CPP)
 add_subdirectory(File)