[CMake] Refactor iOS simulator/device test configuration generation code for LibFuzzer.

[delcypher]

Summary

In order to do this FUZZER_SUPPORTED_OS had to be pulled out of
lib/fuzzer/CMakeLists.txt and into the main config so we can use it
from the test/fuzzer/CMakeList.txt. FUZZER_SUPPORTED_OS currently
has the same value of SANITIZER_COMMON_SUPPORTED_OS which preserves
the existing behaviour but this allows us in the future to adjust the
supported platforms independent of SANITIZER_COMMON_SUPPORTED_OS. This
mirrors the other sanitizers.

For non-Apple platforms FUZZER_SUPPORTED_OS is not defined and
surprisingly this was the behaviour before this patch because
SANITIZER_COMMON_SUPPORTED_OS was actually empty. This appears to
not matter right now because the functions that take an OS as an
argument seem to ignore it on non-Apple platforms.

While this change tries to be NFC it is technically not because we
now generate an iossim config whereas previously we didn't. This seems
like the right thing to do because the build system was configured to
compile LibFuzzer for iossim but previously we weren't generating a lit
test config for it. The device/simulator testing configs don't run by
default anyway so this shouldn't break testing.

This change relies on the get_capitalized_apple_platform() function
added in a previous commit.

rdar://problem/58798733

[delcypher]

Explicitly define LIBFUZZER_TEST_COMPILER

compiler-rt/cmake/config-ix.cmake

if(COMPILER_RT_ENABLE_TVOS)
     set(DARWIN_tvos_SANITIZER_MIN_VER_FLAG
       ${DARWIN_tvos_MIN_VER_FLAG}=9.0)
   endif()
 
   set(SANITIZER_COMMON_SUPPORTED_OS osx)
   set(PROFILE_SUPPORTED_OS osx)
   set(TSAN_SUPPORTED_OS osx)
   set(XRAY_SUPPORTED_OS osx)
+  set(FUZZER_SUPPORTED_OS osx)
 
   # Note: In order to target x86_64h on OS X the minimum deployment target must
   # be 10.8 or higher.
   set(DEFAULT_SANITIZER_MIN_OSX_VERSION 10.10)
   if(NOT SANITIZER_MIN_OSX_VERSION)
     string(REGEX MATCH "-mmacosx-version-min=([.0-9]+)"
            MACOSX_VERSION_MIN_FLAG "${CMAKE_CXX_FLAGS}")
     if(MACOSX_VERSION_MIN_FLAG)
foreach(platform ${DARWIN_EMBEDDED_PLATFORMS})
         darwin_test_archs(${platform}sim
           DARWIN_${platform}sim_ARCHS
           ${toolchain_arches})
         message(STATUS "${platform} Simulator supported arches: ${DARWIN_${platform}sim_ARCHS}")
         if(DARWIN_${platform}sim_ARCHS)
           list(APPEND SANITIZER_COMMON_SUPPORTED_OS ${platform}sim)
           list(APPEND PROFILE_SUPPORTED_OS ${platform}sim)
           list(APPEND TSAN_SUPPORTED_OS ${platform}sim)
+          list(APPEND FUZZER_SUPPORTED_OS ${platform}sim)
         endif()
         foreach(arch ${DARWIN_${platform}sim_ARCHS})
           list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
           set(CAN_TARGET_${arch} 1)
         endforeach()
       endif()
 
       if(DARWIN_${platform}_SYSROOT)
foreach(platform ${DARWIN_EMBEDDED_PLATFORMS})
         if(DARWIN_${platform}_ARCHS)
           list(APPEND SANITIZER_COMMON_SUPPORTED_OS ${platform})
           list(APPEND PROFILE_SUPPORTED_OS ${platform})
 
           list_intersect(DARWIN_${platform}_TSAN_ARCHS DARWIN_${platform}_ARCHS ALL_TSAN_SUPPORTED_ARCH)
           if(DARWIN_${platform}_TSAN_ARCHS)
             list(APPEND TSAN_SUPPORTED_OS ${platform})
           endif()
+          list(APPEND FUZZER_SUPPORTED_OS ${platform})
         endif()
         foreach(arch ${DARWIN_${platform}_ARCHS})
           list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
           set(CAN_TARGET_${arch} 1)
         endforeach()
       endif()
     endforeach()
   endif()

compiler-rt/lib/fuzzer/CMakeLists.txt

if(MSVC)
   # Windows.
   list(APPEND LIBFUZZER_CFLAGS -D_HAS_EXCEPTIONS=0)
 else()
   if(NOT HAS_THREAD_LOCAL)
     list(APPEND LIBFUZZER_CFLAGS -Dthread_local=__thread)
   endif()
 endif()
 
-set(FUZZER_SUPPORTED_OS ${SANITIZER_COMMON_SUPPORTED_OS})
-
 add_compiler_rt_component(fuzzer)
 
 add_compiler_rt_object_libraries(RTfuzzer
   OS ${FUZZER_SUPPORTED_OS}
   ARCHS ${FUZZER_SUPPORTED_ARCH}
   SOURCES ${LIBFUZZER_SOURCES}
   ADDITIONAL_HEADERS ${LIBFUZZER_HEADERS}
   CFLAGS ${LIBFUZZER_CFLAGS}

compiler-rt/test/fuzzer/CMakeLists.txt

if(TARGET cxx_shared)
     test_fuzzer("libc++" DEPS cxx_shared)
   endif()
   if(TARGET cxx_static)
     test_fuzzer("static-libc++" DEPS cxx_static)
   endif()
 endif()
 
 if (APPLE)
-  # FIXME(dliew): This logic should be refactored to the way UBSan Darwin
-  # testing is done.
   set(EXCLUDE_FROM_ALL ON)
-
-  list_intersect(FUZZER_TEST_IOS_ARCHS FUZZER_SUPPORTED_ARCH DARWIN_ios_ARCHS)
-  foreach(arch ${FUZZER_TEST_IOS_ARCHS})
-    set(LIBFUZZER_TEST_APPLE_PLATFORM "ios")
-    set(LIBFUZZER_TEST_TARGET_ARCH ${arch})
+  set(LIBFUZZER_TEST_COMPILER ${COMPILER_RT_TEST_COMPILER})
+  set(FUZZER_APPLE_PLATFORMS ${FUZZER_SUPPORTED_OS})
+  foreach(platform ${FUZZER_APPLE_PLATFORMS})
+    if ("${platform}" STREQUAL "osx")
+      # Skip macOS because it's handled by the code above that builds tests for the host machine.
+      continue()
+    endif()
+    list_intersect(
+      FUZZER_TEST_${platform}_ARCHS
+      FUZZER_SUPPORTED_ARCH
+      DARWIN_${platform}_ARCHS
+    )
+    foreach(arch ${FUZZER_TEST_${platform}_ARCHS})
       get_test_cflags_for_apple_platform(
-      "${LIBFUZZER_TEST_APPLE_PLATFORM}"
-      "${LIBFUZZER_TEST_TARGET_ARCH}"
+        "${platform}"
+        "${arch}"
         LIBFUZZER_TEST_FLAGS
         )
-    set(LIBFUZZER_TEST_CONFIG_SUFFIX "-${arch}-${LIBFUZZER_TEST_APPLE_PLATFORM}")
-    string(TOUPPER ${arch} ARCH_UPPER_CASE)
-    set(CONFIG_NAME "IOS${ARCH_UPPER_CASE}Config")
+      string(TOUPPER "${arch}" ARCH_UPPER_CASE)
+      get_capitalized_apple_platform("${platform}" PLATFORM_CAPITALIZED)
+      set(CONFIG_NAME "${PLATFORM_CAPITALIZED}${ARCH_UPPER_CASE}Config")
+      set(LIBFUZZER_TEST_CONFIG_SUFFIX "-${arch}-${platform}")
+      set(LIBFUZZER_TEST_APPLE_PLATFORM "${platform}")
+      set(LIBFUZZER_TEST_TARGET_ARCH "${arch}")
       configure_lit_site_cfg(
         ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
         ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/lit.site.cfg.py
         )
-    add_lit_testsuite(check-fuzzer-ios-${arch} "libFuzzer iOS ${arch} tests"
+      add_lit_testsuite(check-fuzzer-${platform}-${arch} "libFuzzer ${platform} ${arch} tests"
         ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/
         DEPENDS ${LIBFUZZER_TEST_DEPS})
-
     endforeach()
-
+  endforeach()
   set(EXCLUDE_FROM_ALL OFF)
 endif()