[core] Fixed 'atomic' linking for iOS target (#2137)

Co-authored-by: Jose Santiago <jsantiago@haivision.com>

CMakeLists.txt

@@ -418,8 +418,6 @@ endif()
 #  HAVE_LIBATOMIC
 #  HAVE_GCCATOMIC_INTRINSICS
 #  HAVE_GCCATOMIC_INTRINSICS_REQUIRES_LIBATOMIC
-#  HAVE_GCCATOMIC_INTRINSICS_STATIC
-#  HAVE_GCCATOMIC_INTRINSICS_STATIC_REQUIRES_LIBATOMIC
 include(CheckGCCAtomicIntrinsics)
 CheckGCCAtomicIntrinsics()
 #  HAVE_CXX_ATOMIC
@@ -887,7 +885,7 @@ if (srt_libspec_shared)
 	endif()
 	if (MICROSOFT)
 		target_link_libraries(${TARGET_srt}_shared PRIVATE ws2_32.lib)
-		if (OPENSSL_USE_STATIC_LIBS)			
+		if (OPENSSL_USE_STATIC_LIBS)
 			target_link_libraries(${TARGET_srt}_shared PRIVATE crypt32.lib)
 		else()
 			set_target_properties(${TARGET_srt}_shared PROPERTIES LINK_FLAGS "/DELAYLOAD:libeay32.dll")
@@ -925,7 +923,7 @@ if (srt_libspec_static)
 	endif()
 	if (MICROSOFT)
 		target_link_libraries(${TARGET_srt}_static PRIVATE ws2_32.lib)
-		if (OPENSSL_USE_STATIC_LIBS)			
+		if (OPENSSL_USE_STATIC_LIBS)
 			target_link_libraries(${TARGET_srt}_static PRIVATE crypt32.lib)
 		endif()
 	elseif (MINGW)
@@ -938,8 +936,8 @@ endif()
 
 target_include_directories(srt_virtual PRIVATE  ${SSL_INCLUDE_DIRS})
 
-if (MICROSOFT)		
-	if (OPENSSL_USE_STATIC_LIBS)			
+if (MICROSOFT)
+	if (OPENSSL_USE_STATIC_LIBS)
 		set (SRT_LIBS_PRIVATE ${SRT_LIBS_PRIVATE} ws2_32.lib crypt32.lib)
 	else()
 		set (SRT_LIBS_PRIVATE ${SRT_LIBS_PRIVATE} ws2_32.lib)
@@ -983,9 +981,13 @@ endif()
 
 # Required by some toolchains when statically linking this library if the
 #  GCC Atomic Intrinsics are being used.
-if (HAVE_GCCATOMIC_INTRINSICS
-	AND HAVE_LIBATOMIC)
-	target_link_libraries(${TARGET_srt}_static PUBLIC atomic)
+if (HAVE_GCCATOMIC_INTRINSICS_REQUIRES_LIBATOMIC AND HAVE_LIBATOMIC)
+	if (srt_libspec_static)
+		target_link_libraries(${TARGET_srt}_static PUBLIC atomic)
+	endif()
+	if (srt_libspec_shared)
+		target_link_libraries(${TARGET_srt}_shared PUBLIC atomic)
+	endif()
 endif()
 
 # Cygwin installs the *.dll libraries in bin directory and uses PATH.

scripts/CheckCXXAtomic.cmake

@@ -15,12 +15,11 @@
 
 include(CheckCXXSourceCompiles)
 include(CheckLibraryExists)
-include(UnSetVariableFull)
 
 function(CheckCXXAtomic)
 
-   UnSetVariableFull(HAVE_CXX_ATOMIC)
-   UnSetVariableFull(HAVE_CXX_ATOMIC_STATIC)
+   unset(HAVE_CXX_ATOMIC CACHE)
+   unset(HAVE_CXX_ATOMIC_STATIC CACHE)
 
    unset(CMAKE_REQUIRED_FLAGS)
    unset(CMAKE_REQUIRED_LIBRARIES)
@@ -45,7 +44,12 @@ function(CheckCXXAtomic)
       HAVE_CXX_ATOMIC)
 
    if(HAVE_CXX_ATOMIC)
-      set(CMAKE_REQUIRED_LINK_OPTIONS "-static")
+      # CMAKE_REQUIRED_LINK_OPTIONS was introduced in CMake 3.14.
+      if(CMAKE_VERSION VERSION_LESS "3.14")
+         set(CMAKE_REQUIRED_LINK_OPTIONS "-static")
+      else()
+         set(CMAKE_REQUIRED_FLAGS "-std=c++11 -static")
+      endif()
       check_cxx_source_compiles(
          "${CheckCXXAtomic_CODE}"
          HAVE_CXX_ATOMIC_STATIC)

scripts/CheckGCCAtomicIntrinsics.cmake

@@ -13,24 +13,19 @@
 #     HAVE_LIBATOMIC
 #     HAVE_GCCATOMIC_INTRINSICS
 #     HAVE_GCCATOMIC_INTRINSICS_REQUIRES_LIBATOMIC
-#     HAVE_GCCATOMIC_INTRINSICS_STATIC
-#     HAVE_GCCATOMIC_INTRINSICS_STATIC_REQUIRES_LIBATOMIC
 #
 # See
 #  https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
 #  https://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync
 
 include(CheckCSourceCompiles)
 include(CheckLibraryExists)
-include(UnSetVariableFull)
 
 function(CheckGCCAtomicIntrinsics)
 
-   UnSetVariableFull(HAVE_LIBATOMIC)
-   UnSetVariableFull(HAVE_GCCATOMIC_INTRINSICS)
-   UnSetVariableFull(HAVE_GCCATOMIC_INTRINSICS_REQUIRES_LIBATOMIC)
-   UnSetVariableFull(HAVE_GCCATOMIC_INTRINSICS_STATIC)
-   UnSetVariableFull(HAVE_GCCATOMIC_INTRINSICS_STATIC_REQUIRES_LIBATOMIC)
+   unset(HAVE_LIBATOMIC CACHE)
+   unset(HAVE_GCCATOMIC_INTRINSICS CACHE)
+   unset(HAVE_GCCATOMIC_INTRINSICS_REQUIRES_LIBATOMIC CACHE)
 
    unset(CMAKE_REQUIRED_FLAGS)
    unset(CMAKE_REQUIRED_LIBRARIES)
@@ -54,12 +49,12 @@ function(CheckGCCAtomicIntrinsics)
    check_library_exists(
       atomic __atomic_fetch_add_8 "" HAVE_LIBATOMIC)
 
+   set(CMAKE_TRY_COMPILE_TARGET_TYPE EXECUTABLE) # CMake 3.6
    check_c_source_compiles(
       "${CheckGCCAtomicIntrinsics_CODE}"
       HAVE_GCCATOMIC_INTRINSICS)
 
-   if (NOT HAVE_GCCATOMIC_INTRINSICS
-      AND HAVE_LIBATOMIC)
+   if (NOT HAVE_GCCATOMIC_INTRINSICS AND HAVE_LIBATOMIC)
       set(CMAKE_REQUIRED_LIBRARIES "atomic")
       check_c_source_compiles(
          "${CheckGCCAtomicIntrinsics_CODE}"
@@ -69,29 +64,4 @@ function(CheckGCCAtomicIntrinsics)
       endif()
    endif()
 
-   unset(CMAKE_REQUIRED_FLAGS)
-   unset(CMAKE_REQUIRED_LIBRARIES)
-   unset(CMAKE_REQUIRED_LINK_OPTIONS)
-
-   if (HAVE_GCCATOMIC_INTRINSICS)
-      set(CMAKE_REQUIRED_LINK_OPTIONS "-static")
-      check_c_source_compiles(
-         "${CheckGCCAtomicIntrinsics_CODE}"
-         HAVE_GCCATOMIC_INTRINSICS_STATIC)
-      if (NOT HAVE_GCCATOMIC_INTRINSICS_STATIC
-         AND HAVE_LIBATOMIC)
-         set(CMAKE_REQUIRED_LIBRARIES "atomic")
-         check_c_source_compiles(
-            "${CheckGCCAtomicIntrinsics_CODE}"
-            HAVE_GCCATOMIC_INTRINSICS_STATIC)
-         if (HAVE_GCCATOMIC_INTRINSICS_STATIC)
-            set(HAVE_GCCATOMIC_INTRINSICS_STATIC_REQUIRES_LIBATOMIC TRUE PARENT_SCOPE)
-         endif()
-      endif()
-   endif()
-
-   unset(CMAKE_REQUIRED_FLAGS)
-   unset(CMAKE_REQUIRED_LIBRARIES)
-   unset(CMAKE_REQUIRED_LINK_OPTIONS)
-
 endfunction(CheckGCCAtomicIntrinsics)

scripts/FindPThreadGetSetName.cmake

@@ -27,14 +27,13 @@
 #     add_definitions(-DHAVE_PTHREAD_SETNAME_NP=1)
 
 include(CheckSymbolExists)
-include(UnSetVariableFull)
 
 function(FindPThreadGetSetName)
 
-   UnSetVariableFull(HAVE_PTHREAD_GETNAME_NP_IN_PTHREAD_NP_H)
-   UnSetVariableFull(HAVE_PTHREAD_SETNAME_NP_IN_PTHREAD_NP_H)
-   UnSetVariableFull(HAVE_PTHREAD_GETNAME_NP)
-   UnSetVariableFull(HAVE_PTHREAD_SETNAME_NP)
+   unset(HAVE_PTHREAD_GETNAME_NP_IN_PTHREAD_NP_H CACHE)
+   unset(HAVE_PTHREAD_SETNAME_NP_IN_PTHREAD_NP_H CACHE)
+   unset(HAVE_PTHREAD_GETNAME_NP CACHE)
+   unset(HAVE_PTHREAD_SETNAME_NP CACHE)
 
    set(CMAKE_REQUIRED_DEFINITIONS
       -D_GNU_SOURCE -D_DARWIN_C_SOURCE -D_POSIX_SOURCE=1)
@@ -55,11 +54,11 @@ function(FindPThreadGetSetName)
    message(STATUS "Checking for pthread_(g/s)etname_np in 'pthread.h':")
    check_symbol_exists(pthread_getname_np "pthread.h" HAVE_PTHREAD_GETNAME_NP)
    if (HAVE_PTHREAD_GETNAME_NP_IN_PTHREAD_NP_H)
-      set(HAVE_PTHREAD_GETNAME_NP TRUE PARENT_SCOPE)
+      set(HAVE_PTHREAD_GETNAME_NP 1 CACHE INTERNAL "" FORCE)
    endif()
    check_symbol_exists(pthread_setname_np "pthread.h" HAVE_PTHREAD_SETNAME_NP)
    if (HAVE_PTHREAD_SETNAME_NP_IN_PTHREAD_NP_H)
-      set(HAVE_PTHREAD_SETNAME_NP TRUE PARENT_SCOPE)
+      set(HAVE_PTHREAD_SETNAME_NP 1 CACHE INTERNAL "" FORCE)
    endif()
    if (HAVE_PTHREAD_GETNAME_NP)
       add_definitions(-DHAVE_PTHREAD_GETNAME_NP=1)