Add option to toggle Objective-C exception support

CMakeLists.txt

@@ -94,7 +94,6 @@ set(libobjc_HDRS
 	objc/objc-arc.h
 	objc/objc-auto.h
 	objc/objc-class.h
-	objc/objc-exception.h
 	objc/objc-runtime.h
 	objc/objc-visibility.h
 	objc/objc.h
@@ -107,12 +106,6 @@ set(libobjc_CXX_SRCS
 	selector_table.cc
 	)
 
-# Windows does not use DWARF EH, except when using the GNU ABI (MinGW)
-if (WIN32 AND NOT MINGW)
-	list(APPEND libobjc_CXX_SRCS eh_win32_msvc.cc)
-elseif (NOT MINGW)
-	list(APPEND libobjc_C_SRCS eh_personality.c)
-endif ()
 
 find_package(tsl-robin-map)
 
@@ -141,6 +134,7 @@ option(LEGACY_COMPAT "Enable legacy compatibility features" OFF)
 option(DEBUG_ARC_COMPAT
 	"Log warnings for classes that don't hit ARC fast paths" OFF)
 option(ENABLE_OBJCXX "Enable support for Objective-C++" ON)
+option(ENABLE_EXCEPTIONS "Enable exceptions" ON)
 option(TESTS "Enable building the tests")
 option(EMBEDDED_BLOCKS_RUNTIME "Include an embedded blocks runtime, rather than relying on libBlocksRuntime to supply it" ON)
 option(STRICT_APPLE_COMPATIBILITY "Use strict Apple compatibility, always defining BOOL as signed char" OFF)
@@ -161,6 +155,17 @@ if (EMBEDDED_BLOCKS_RUNTIME)
 	list(APPEND libobjc_C_SRCS block_to_imp.c)
 endif()
 
+if (ENABLE_EXCEPTIONS)
+	# Windows does not use DWARF EH, except when using the GNU ABI (MinGW)
+	if (WIN32 AND NOT MINGW)
+		list(APPEND libobjc_CXX_SRCS eh_win32_msvc.cc)
+	elseif (NOT MINGW)
+		list(APPEND libobjc_C_SRCS eh_personality.c)
+	endif ()
+
+	list(APPEND libobjc_HDRS objc/objc-exception.h)
+endif()
+
 if (OLDABI_COMPAT)
 	list(APPEND libobjc_C_SRCS legacy.c abi_version.c statics_loader.c)
 	add_definitions(-DOLDABI_COMPAT=1)
@@ -220,23 +225,25 @@ endif()
 
 
 
-if (WIN32 AND NOT MINGW)
-	message(STATUS "Using MSVC-compatible exception model")
-elseif (MINGW)
-	message(STATUS "Using MinGW-compatible exception model")
-	list(APPEND libobjc_CXX_SRCS objcxx_eh.cc objcxx_eh_mingw.cc)
-else ()
-	set(EH_PERSONALITY_FLAGS "")
-	if (CMAKE_CXX_COMPILER_TARGET)
-		list(APPEND EH_PERSONALITY_FLAGS "${CMAKE_CXX_COMPILE_OPTIONS_TARGET}${CMAKE_CXX_COMPILER_TARGET}")
+if (ENABLE_EXCEPTIONS)
+	if (WIN32 AND NOT MINGW)
+		message(STATUS "Using MSVC-compatible exception model")
+	elseif (MINGW)
+		message(STATUS "Using MinGW-compatible exception model")
+		list(APPEND libobjc_CXX_SRCS objcxx_eh.cc objcxx_eh_mingw.cc)
+	else ()
+		set(EH_PERSONALITY_FLAGS "")
+		if (CMAKE_CXX_COMPILER_TARGET)
+			list(APPEND EH_PERSONALITY_FLAGS "${CMAKE_CXX_COMPILE_OPTIONS_TARGET}${CMAKE_CXX_COMPILER_TARGET}")
+		endif ()
+		add_custom_command(OUTPUT eh_trampoline.S
+			COMMAND ${CMAKE_CXX_COMPILER} ARGS ${EH_PERSONALITY_FLAGS} -fPIC -S "${CMAKE_SOURCE_DIR}/eh_trampoline.cc" -o - -fexceptions -fno-inline | sed "s/__gxx_personality_v0/test_eh_personality/g" > "${CMAKE_BINARY_DIR}/eh_trampoline.S"
+			MAIN_DEPENDENCY eh_trampoline.cc)
+		list(APPEND libobjc_ASM_SRCS eh_trampoline.S)
+		list(APPEND libobjc_CXX_SRCS objcxx_eh.cc)
+		# Find libm for linking, as some versions of libc++ don't link against it
+		find_library(M_LIBRARY m)
 	endif ()
-	add_custom_command(OUTPUT eh_trampoline.S
-		COMMAND ${CMAKE_CXX_COMPILER} ARGS ${EH_PERSONALITY_FLAGS} -fPIC -S "${CMAKE_SOURCE_DIR}/eh_trampoline.cc" -o - -fexceptions -fno-inline | sed "s/__gxx_personality_v0/test_eh_personality/g" > "${CMAKE_BINARY_DIR}/eh_trampoline.S"
-		MAIN_DEPENDENCY eh_trampoline.cc)
-	list(APPEND libobjc_ASM_SRCS eh_trampoline.S)
-	list(APPEND libobjc_CXX_SRCS objcxx_eh.cc)
-	# Find libm for linking, as some versions of libc++ don't link against it
-	find_library(M_LIBRARY m)
 endif ()
 
 if (EMBEDDED_BLOCKS_RUNTIME)
@@ -256,7 +263,9 @@ else ()
 endif ()
 
 add_library(objc SHARED ${libobjc_C_SRCS} ${libobjc_ASM_SRCS} ${libobjc_OBJC_SRCS} ${libobjc_OBJCXX_SRCS} ${libobjc_ASM_OBJS})
-target_compile_options(objc PRIVATE "$<$<OR:$<COMPILE_LANGUAGE:OBJC>,$<COMPILE_LANGUAGE:OBJCXX>>:-Wno-gnu-folding-constant;-Wno-deprecated-objc-isa-usage;-Wno-objc-root-class;-fobjc-runtime=gnustep-2.0>$<$<COMPILE_LANGUAGE:C>:-Xclang;-fexceptions;-Wno-gnu-folding-constant>")
+
+#target_compile_options(objc PRIVATE "$<$<OR:$<COMPILE_LANGUAGE:OBJC>,$<COMPILE_LANGUAGE:OBJCXX>>:-Wno-gnu-folding-constant;-Wno-deprecated-objc-isa-usage;-Wno-objc-root-class;-fobjc-runtime=gnustep-2.0>$<$<COMPILE_LANGUAGE:C>:-Xclang;-fexceptions;-Wno-gnu-folding-constant>")
+target_compile_options(objc PRIVATE "$<$<OR:$<COMPILE_LANGUAGE:OBJC>,$<COMPILE_LANGUAGE:OBJCXX>>:-Wno-gnu-folding-constant;-fno-exceptions;-fno-objc-exceptions;-Wno-deprecated-objc-isa-usage;-Wno-objc-root-class;-fobjc-runtime=gnustep-2.0>$<$<COMPILE_LANGUAGE:C>:-Xclang;-Wno-gnu-folding-constant>")
 
 list(APPEND libobjc_CXX_SRCS ${libobjcxx_CXX_SRCS})
 target_sources(objc PRIVATE ${libobjc_CXX_SRCS})
@@ -466,13 +475,15 @@ if (TESTS)
 	add_subdirectory(Test)
 endif (TESTS)
 
-CHECK_CXX_SOURCE_COMPILES("
-	#include <stdlib.h>
-	extern \"C\" {
-	__attribute__((weak))
-	void *__cxa_allocate_exception(size_t thrown_size) noexcept;
-	}
-	#include <exception>
-	int main() { return 0; }" CXA_ALLOCATE_EXCEPTION_NOEXCEPT_COMPILES)
-
-add_compile_definitions($<IF:$<BOOL:${CXA_ALLOCATE_EXCEPTION_NOEXCEPT_COMPILES}>,CXA_ALLOCATE_EXCEPTION_SPECIFIER=noexcept,CXA_ALLOCATE_EXCEPTION_SPECIFIER>)
+if (ENABLE_EXCEPTIONS)
+	CHECK_CXX_SOURCE_COMPILES("
+		#include <stdlib.h>
+		extern \"C\" {
+		__attribute__((weak))
+		void *__cxa_allocate_exception(size_t thrown_size) noexcept;
+		}
+		#include <exception>
+		int main() { return 0; }" CXA_ALLOCATE_EXCEPTION_NOEXCEPT_COMPILES)
+
+	add_compile_definitions($<IF:$<BOOL:${CXA_ALLOCATE_EXCEPTION_NOEXCEPT_COMPILES}>,CXA_ALLOCATE_EXCEPTION_SPECIFIER=noexcept,CXA_ALLOCATE_EXCEPTION_SPECIFIER>)
+endif()

Test/CMakeLists.txt

@@ -1,4 +1,3 @@
-
 # Clear the LD_LIBRARY_PATH if GNUstep set it so that we don't accidentally use
 # the installed version
 
@@ -19,13 +18,11 @@ set(TESTS
 	BlockTest_arc.m
 	ConstantString.m
 	Category.m
-	ExceptionTest.m
 	FastARC.m
 	FastARCPool.m
 	FastRefCount.m
 	Forward.m
 	ManyManySelectors.m
-	NestedExceptions.m
 	PropertyAttributeTest.m
 	ProtocolExtendedProperties.m
 	PropertyIntrospectionTest.m
@@ -43,16 +40,36 @@ set(TESTS
 	IVarSuperclassOverlap.m
 	objc_msgSend.m
 	msgInterpose.m
-	NilException.m
 	MethodArguments.m
 	zeroSizedIVar.m
 	exchange.m
 	hash_table_delete.c
 	hash_test.c
 	setSuperclass.m
-	UnexpectedException.m
 )
 
+if (ENABLE_EXCEPTIONS)
+	set(ADDITIONAL_CFLAGS "-fobjc-exceptions")
+
+	list(APPEND TESTS
+		ExceptionTest.m
+		NestedExceptions.m
+		NilException.m
+		UnexpectedException.m
+	)
+
+	# Don't run the tests that are specific to Itanium-style exceptions on
+	# Windows.
+	if (NOT WIN32)
+		list(APPEND TESTS
+			BoxedForeignException.m
+			ForeignException.m
+		)
+	endif()
+else()
+	set(ADDITIONAL_CFLAGS "-fno-objc-exceptions")
+endif()
+
 if (EMBEDDED_BLOCKS_RUNTIME)
 	list(APPEND TESTS BlockImpTest.m)
 endif()
@@ -73,13 +90,6 @@ if (WIN32)
 			objc_msgSend_WoA64.mm
 		)
 	endif()
-else ()
-	# Don't run the tests that are specific to Itanium-style exceptions on
-	# Windows.
-	list(APPEND TESTS
-	BoxedForeignException.m
-	ForeignException.m
-	)
 endif ()
 
 if (ENABLE_ALL_OBJC_ARC_TESTS)
@@ -102,14 +112,14 @@ remove_definitions(-D__OBJC_RUNTIME_INTERNAL__=1)
 add_library(test_runtime_legacy OBJECT Test.m)
 set_target_properties(test_runtime_legacy PROPERTIES
 	INCLUDE_DIRECTORIES "${CMAKE_SOURCE_DIR};${PROJECT_BINARY_DIR}/objc/"
-	COMPILE_FLAGS "-Xclang -fblocks -fobjc-runtime=gnustep-1.7"
+	COMPILE_FLAGS "-Xclang -fblocks -fobjc-runtime=gnustep-1.7 ${ADDITIONAL_CFLAGS}"
 	LINKER_LANGUAGE C
 )
 
 add_library(test_runtime OBJECT Test.m)
 set_target_properties(test_runtime PROPERTIES
 	INCLUDE_DIRECTORIES "${CMAKE_SOURCE_DIR};${PROJECT_BINARY_DIR}/objc/"
-	COMPILE_FLAGS "-Xclang -fblocks -fobjc-runtime=gnustep-2.0"
+	COMPILE_FLAGS "-Xclang -fblocks -fobjc-runtime=gnustep-2.0 ${ADDITIONAL_CFLAGS}"
 	LINKER_LANGUAGE C
 )
 
@@ -142,16 +152,16 @@ function(addtest_flags TEST_NAME FLAGS TEST_SOURCE)
 endfunction(addtest_flags)
 
 function(addtest_variants TEST TEST_SOURCE LEGACY)
-	addtest_flags(${TEST} "-O0 -fobjc-runtime=gnustep-2.2 -UNDEBUG -DGS_RUNTIME_V2" "${TEST_SOURCE}")
+	addtest_flags(${TEST} "-O0 -fobjc-runtime=gnustep-2.2 ${ADDITIONAL_CFLAGS} -UNDEBUG -DGS_RUNTIME_V2" "${TEST_SOURCE}")
 	target_sources(${TEST} PRIVATE $<TARGET_OBJECTS:test_runtime>)
-	addtest_flags("${TEST}_optimised" "-O3 -fobjc-runtime=gnustep-2.2 -UNDEBUG -DGS_RUNTIME_V2" "${TEST_SOURCE}")
+	addtest_flags("${TEST}_optimised" "-O3 -fobjc-runtime=gnustep-2.2 ${ADDITIONAL_CFLAGS} -UNDEBUG -DGS_RUNTIME_V2" "${TEST_SOURCE}")
 	target_sources("${TEST}_optimised" PRIVATE $<TARGET_OBJECTS:test_runtime>)
 
 	# -fobjc-arc is not supported on platforms using the legacy runtime
 	if (${LEGACY} AND ${OLDABI_COMPAT} AND NOT ${TEST} MATCHES ".*_arc")
-		addtest_flags("${TEST}_legacy" "-O0 -fobjc-runtime=gnustep-1.7 -UNDEBUG" "${TEST_SOURCE}")
+		addtest_flags("${TEST}_legacy" "-O0 -fobjc-runtime=gnustep-1.7 ${ADDITIONAL_CFLAGS} -UNDEBUG" "${TEST_SOURCE}")
 		target_sources("${TEST}_legacy" PRIVATE $<TARGET_OBJECTS:test_runtime_legacy>)
-		addtest_flags("${TEST}_legacy_optimised" "-O3 -fobjc-runtime=gnustep-1.7 -UNDEBUG" "${TEST_SOURCE}")
+		addtest_flags("${TEST}_legacy_optimised" "-O3 -fobjc-runtime=gnustep-1.7 ${ADDITIONAL_CFLAGS} -UNDEBUG" "${TEST_SOURCE}")
 		target_sources("${TEST}_legacy_optimised" PRIVATE $<TARGET_OBJECTS:test_runtime_legacy>)
 	endif()
 endfunction(addtest_variants)
@@ -166,18 +176,20 @@ foreach(TEST_SOURCE ${NEW_TESTS})
 	addtest_variants(${TEST} ${TEST_SOURCE} false)
 endforeach()
 
-# Tests that are more than a single file.
-addtest_variants("CXXExceptions" "CXXException.m;CXXException.cc" true)
-addtest_variants("ForwardDeclareProtocolAccess" "ForwardDeclareProtocolAccess.m;ForwardDeclareProtocol.m" true)
-if (ENABLE_OBJCXX)
-	addtest_variants(ObjCXXEHInterop "ObjCXXEHInterop.mm;ObjCXXEHInterop.m" true)
-	addtest_variants(ObjCXXEHInteropTwice "ObjCXXEHInteropTwice.mm" true)
-	if (WIN32 AND CMAKE_CXX_COMPILER_ID STREQUAL Clang)
-		if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 16.0.0)
+if (ENABLE_EXCEPTIONS)
+	# Tests that are more than a single file.
+	addtest_variants("CXXExceptions" "CXXException.m;CXXException.cc" true)
+	addtest_variants("ForwardDeclareProtocolAccess" "ForwardDeclareProtocolAccess.m;ForwardDeclareProtocol.m" true)
+	if (ENABLE_OBJCXX)
+		addtest_variants(ObjCXXEHInterop "ObjCXXEHInterop.mm;ObjCXXEHInterop.m" true)
+		addtest_variants(ObjCXXEHInteropTwice "ObjCXXEHInteropTwice.mm" true)
+		if (WIN32 AND CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+			if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 16.0.0)
+				addtest_variants(ObjCXXEHInterop_arc "ObjCXXEHInterop_arc.mm;ObjCXXEHInterop_arc.m" true)
+			endif()
+		else()
 			addtest_variants(ObjCXXEHInterop_arc "ObjCXXEHInterop_arc.mm;ObjCXXEHInterop_arc.m" true)
 		endif()
-	else()
-		addtest_variants(ObjCXXEHInterop_arc "ObjCXXEHInterop_arc.mm;ObjCXXEHInterop_arc.m" true)
 	endif()
 endif()
 

Test/RuntimeTest.m

@@ -78,7 +78,9 @@ - (int) manyTypes;
 - (void) synchronizedCode;
 + (void) synchronizedCode;
 + (id) shared;
+#if __has_feature(objc_exceptions)
 - (BOOL) basicThrowAndCatchException;
+#endif
 @end
 
 @interface Bar : Foo
@@ -117,6 +119,8 @@ + (id) shared
 	@synchronized(self) { }
 	return nil;
 }
+
+#if __has_feature(objc_exceptions)
 - (void) throwException
 {
 	@throw exceptionObj;
@@ -138,6 +142,7 @@ - (BOOL) basicThrowAndCatchException
 	}
 	return NO;
 }
+#endif
 @end
 
 @implementation Bar
@@ -282,6 +287,7 @@ void testSynchronized()
   printf("testSynchronized() ran\n");
 }
 
+#if __has_feature(objc_exceptions)
 void testExceptions()
 {
   Foo *foo = [Foo new];
@@ -290,6 +296,7 @@ void testExceptions()
   printf("testExceptions() ran\n");
 
 }
+#endif
 
 void testRegisterAlias()
 {
@@ -336,7 +343,9 @@ int main (int argc, const char * argv[])
   printf("Instance of NSObject: %p\n", class_createInstance([NSObject class], 0));
 
   testSynchronized();
+#if __has_feature(objc_exceptions)
   testExceptions();
+#endif
   testRegisterAlias();
 
   return exitStatus;

Test/objc_msgSend.m

@@ -92,7 +92,9 @@ + (void)printf: (const char*)str, ...
 + (void)initialize
 {
 	[self printf: "Format %s %d %f%c", "string", 42, 42.0, '\n'];
+#if __has_feature(objc_exceptions)
 	@throw self;
+#endif
 }
 + nothing { return 0; }
 @end
@@ -180,6 +182,8 @@ int main(void)
 	__objc_msg_forward2 = forward;
 	__objc_msg_forward3 = forward_slot;
 	TestCls = objc_getClass("MsgTest");
+
+#if __has_feature(objc_exceptions)
 	int exceptionThrown = 0;
 	@try {
 		objc_msgSend(TestCls, @selector(foo));
@@ -189,6 +193,8 @@ int main(void)
 		exceptionThrown = 1;
 	}
 	assert(exceptionThrown && "An exception was thrown");
+#endif
+
 	assert((id)0x42 == objc_msgSend(TestCls, @selector(foo)));
 	objc_msgSend(TestCls, @selector(nothing));
 	objc_msgSend(TestCls, @selector(missing));

associate.m

@@ -168,6 +168,7 @@ static void setReference(struct reference_list *list,
 		lock = lock_for_pointer(r);
 		lock_spinlock(lock);
 	}
+#if __has_feature(objc_exceptions)
 	@try
 	{
 		if (OBJC_ASSOCIATION_ASSIGN != r->policy)
@@ -180,6 +181,14 @@ static void setReference(struct reference_list *list,
 		r->policy = policy;
 		r->object = obj;
 	}
+#else
+	if (OBJC_ASSOCIATION_ASSIGN != r->policy)
+	{
+		objc_release(r->object);
+	}
+	r->policy = policy;
+	r->object = obj;
+#endif // __has_feature(objc_exceptions)
 	if (needLock)
 	{
 		unlock_spinlock(lock);