[libcxx-commits] [libcxxabi] 76b1a7c - [libc++][Android] Explicitly declare low-level lib existence (#70534)

[via libcxx-commits]

Author: Ryan Prichard
Date: 2023-11-03T12:54:55-07:00
New Revision: 76b1a7c91651b8c3516913ce9b11c05147ec46d2

URL: https://github.com/llvm/llvm-project/commit/76b1a7c91651b8c3516913ce9b11c05147ec46d2
DIFF: https://github.com/llvm/llvm-project/commit/76b1a7c91651b8c3516913ce9b11c05147ec46d2.diff

LOG: [libc++][Android] Explicitly declare low-level lib existence (#70534)

Android's librt and libpthread functionality is part of libc.{a,so}
instead. The atomic APIs are part of the compiler-rt builtins archive.
Android does have libdl.

Android's libc.so has `__cxa_thread_atexit_impl` starting in API 23, and
the oldest supported API is 21, so continue using feature detection for
that API.

These settings need to be declared explicitly for the sake of the fuzzer
library's custom libc++ build `add_custom_libcxx`. That macro builds
libc++ using `-DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY`, which
breaks the feature detection.

Added: 
    

Modified: 
    libcxx/cmake/config-ix.cmake
    libcxxabi/cmake/config-ix.cmake

Removed: 
    


################################################################################
diff  --git a/libcxx/cmake/config-ix.cmake b/libcxx/cmake/config-ix.cmake
index 9fed861a4e193c5..a365517936e7565 100644
--- a/libcxx/cmake/config-ix.cmake
+++ b/libcxx/cmake/config-ix.cmake
@@ -107,6 +107,10 @@ elseif(FUCHSIA)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   check_library_exists(atomic __atomic_fetch_add_8 "" LIBCXX_HAS_ATOMIC_LIB)
+elseif(ANDROID)
+  set(LIBCXX_HAS_PTHREAD_LIB NO)
+  set(LIBCXX_HAS_RT_LIB NO)
+  set(LIBCXX_HAS_ATOMIC_LIB NO)
 else()
   check_library_exists(pthread pthread_create "" LIBCXX_HAS_PTHREAD_LIB)
   check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB)

diff  --git a/libcxxabi/cmake/config-ix.cmake b/libcxxabi/cmake/config-ix.cmake
index 702fe7d1d72f777..39b9284b780ebcf 100644
--- a/libcxxabi/cmake/config-ix.cmake
+++ b/libcxxabi/cmake/config-ix.cmake
@@ -95,6 +95,11 @@ if(FUCHSIA)
   set(LIBCXXABI_HAS_PTHREAD_LIB NO)
   check_library_exists(c __cxa_thread_atexit_impl ""
     LIBCXXABI_HAS_CXA_THREAD_ATEXIT_IMPL)
+elseif(ANDROID)
+  set(LIBCXXABI_HAS_DL_LIB YES)
+  set(LIBCXXABI_HAS_PTHREAD_LIB NO)
+  check_library_exists(c __cxa_thread_atexit_impl ""
+    LIBCXXABI_HAS_CXA_THREAD_ATEXIT_IMPL)
 else()
   check_library_exists(dl dladdr "" LIBCXXABI_HAS_DL_LIB)
   check_library_exists(pthread pthread_once "" LIBCXXABI_HAS_PTHREAD_LIB)