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Merged
davidchisnall merged 1 commit into from
Aug 29, 2026
+74 −35
Merged

Add support for building a static libobjc2 for WebAssembly #422

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109 changes: 74 additions & 35 deletions CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,24 @@ message(STATUS "Architecture as detected by CMake: ${CMAKE_SYSTEM_PROCESSOR}")
# Build configuration
add_compile_definitions(GNUSTEP __OBJC_RUNTIME_INTERNAL__=1 __OBJC_BOOL)

set(BUILD_SHARED_LIBOBJC_DEFAULT ON)
set(BUILD_STATIC_LIBOBJC_DEFAULT OFF)

option(WASM "Build WebAssembly-specific runtime support" "${EMSCRIPTEN}")

if (WASM)
# For WebAssembly, libobjc2 should generally be linked statically.
set(BUILD_SHARED_LIBOBJC_DEFAULT OFF)
set(BUILD_STATIC_LIBOBJC_DEFAULT ON)
endif ()

option(BUILD_SHARED_LIBOBJC "Build the shared version of libobjc" ${BUILD_SHARED_LIBOBJC_DEFAULT})
option(BUILD_STATIC_LIBOBJC "Build the static version of libobjc" ${BUILD_STATIC_LIBOBJC_DEFAULT})

if (NOT BUILD_SHARED_LIBOBJC AND NOT BUILD_STATIC_LIBOBJC)
message(FATAL_ERROR "At least one of BUILD_SHARED_LIBOBJC and BUILD_STATIC_LIBOBJC must be enabled.")
endif ()



set(libobjc_ASM_SRCS
Expand Down Expand Up @@ -125,7 +143,7 @@ if (NOT tsl-robin-map_FOUND)
FetchContent_MakeAvailable(robinmap)
endif()

if (WIN32)
if (WIN32 OR WASM)
set(OLD_ABI_COMPAT_DEFAULT false)
else()
set(OLD_ABI_COMPAT_DEFAULT true)
Expand All @@ -137,6 +155,9 @@ option(ENABLE_TRACING
option(OLDABI_COMPAT
"Enable compatibility with GCC and old GNUstep ABIs"
${OLD_ABI_COMPAT_DEFAULT})
if (WASM AND OLDABI_COMPAT)
message(FATAL_ERROR "WebAssembly builds only support the version 2 Objective-C ABI. Please disable OLDABI_COMPAT.")
endif ()
option(LEGACY_COMPAT "Enable legacy compatibility features" OFF)
option(DEBUG_ARC_COMPAT
"Log warnings for classes that don't hit ARC fast paths" OFF)
Expand All @@ -156,10 +177,16 @@ add_compile_definitions($<$<BOOL:${STRICT_APPLE_COMPATIBILITY}>:STRICT_APPLE_COM
configure_file(objc/objc-config.h.in objc/objc-config.h @ONLY)
include_directories("${PROJECT_BINARY_DIR}/objc/")

if (EMBEDDED_BLOCKS_RUNTIME)
if (WASM)
# WebAssembly has no native dispatch assembly or Objective-C fast paths.
set(libobjc_ASM_SRCS)
list(REMOVE_ITEM libobjc_C_SRCS fast_paths.m)
endif ()

if (EMBEDDED_BLOCKS_RUNTIME AND NOT WASM)
list(APPEND libobjc_ASM_SRCS block_trampolines.S)
list(APPEND libobjc_C_SRCS block_to_imp.c)
endif()
endif ()

if (OLDABI_COMPAT)
list(APPEND libobjc_C_SRCS legacy.c abi_version.c statics_loader.c)
Expand Down Expand Up @@ -188,7 +215,7 @@ if (CMAKE_SYSTEM_PROCESSOR STREQUAL "ppc" OR CMAKE_SYSTEM_PROCESSOR STREQUAL "pp
add_definitions(-DNO_SAFE_CACHING)
endif()

set(INSTALL_TARGETS objc)
set(INSTALL_TARGETS)

if(WIN32)
if(CMAKE_ASM_COMPILER_TARGET)
Expand Down Expand Up @@ -227,6 +254,9 @@ if (WIN32 AND NOT MINGW)
elseif (MINGW)
message(STATUS "Using MinGW-compatible exception model")
list(APPEND libobjc_CXX_SRCS objcxx_eh.cc objcxx_eh_mingw.cc)
elseif (WASM)
list(REMOVE_ITEM libobjc_C_SRCS eh_personality.c)
list(APPEND libobjc_CXX_SRCS objc_wasm_eh.cc)
else ()
set(EH_PERSONALITY_FLAGS "")
if (CMAKE_CXX_COMPILER_TARGET)
Expand Down Expand Up @@ -257,19 +287,8 @@ else ()
endif ()
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_features(objc PRIVATE cxx_std_20)

list(APPEND libobjc_CXX_SRCS ${libobjcxx_CXX_SRCS})
target_sources(objc PRIVATE ${libobjc_CXX_SRCS})

include(FindThreads)
target_link_libraries(objc PUBLIC Threads::Threads)
# Link against ntdll.dll for RtlRaiseException
if (WIN32 AND NOT MINGW)
target_link_libraries(objc PUBLIC ntdll.dll)
endif()

if (NOT EMBEDDED_BLOCKS_RUNTIME)
# Check if the blocks runtime exports _Block_use_RR2
Expand All @@ -283,27 +302,43 @@ if (NOT EMBEDDED_BLOCKS_RUNTIME)
message(FATAL_ERROR "The external blocks runtime is not supported. It does not export _Block_use_RR2().")
endif()

target_compile_definitions(objc PRIVATE HAVE_BLOCK_USE_RR2)
target_link_libraries(objc PUBLIC BlocksRuntime::BlocksRuntime)
endif()

target_link_libraries(objc PRIVATE tsl::robin_map)

set_target_properties(objc PROPERTIES
LINKER_LANGUAGE C
SOVERSION ${libobjc_VERSION}
OUTPUT_NAME ${LIBOBJC_NAME}
LINK_FLAGS "${objc_LINK_FLAGS}"
)

set_property(TARGET PROPERTY NO_SONAME true)
if (BUILD_SHARED_LIBOBJC)
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_features(objc PRIVATE cxx_std_20)
target_sources(objc PRIVATE ${libobjc_CXX_SRCS})
target_link_libraries(objc PUBLIC Threads::Threads)
# Link against ntdll.dll for RtlRaiseException
if (WIN32 AND NOT MINGW)
target_link_libraries(objc PUBLIC ntdll.dll)
endif()
if (NOT EMBEDDED_BLOCKS_RUNTIME)
target_compile_definitions(objc PRIVATE HAVE_BLOCK_USE_RR2)
target_link_libraries(objc PUBLIC BlocksRuntime::BlocksRuntime)
endif()
target_link_libraries(objc PRIVATE tsl::robin_map)
set_target_properties(objc PROPERTIES
LINKER_LANGUAGE C
SOVERSION ${libobjc_VERSION}
OUTPUT_NAME ${LIBOBJC_NAME}
LINK_FLAGS "${objc_LINK_FLAGS}"
)
set_property(TARGET objc PROPERTY NO_SONAME true)
list(APPEND INSTALL_TARGETS objc)
endif ()

option(BUILD_STATIC_LIBOBJC "Build the static version of libobjc" OFF)
if (BUILD_STATIC_LIBOBJC)
add_library(objc-static STATIC ${libobjc_C_SRCS} ${libobjc_ASM_SRCS} ${libobjc_OBJC_SRCS} ${libobjc_OBJCXX_SRCS} ${libobjc_CXX_SRCS})
target_compile_options(objc-static PRIVATE "$<$<OR:$<COMPILE_LANGUAGE:OBJC>,$<COMPILE_LANGUAGE:OBJCXX>>:-Wno-gnu-folding-constant;-Wno-deprecated-objc-isa-usage;-Wno-objc-root-class;-fobjc-runtime=gnustep-2.0>$<$<COMPILE_LANGUAGE:C>:-Xclang;-fexceptions;-Wno-gnu-folding-constant>")
target_compile_features(objc-static PRIVATE cxx_std_20)
target_link_libraries(objc-static PRIVATE tsl::robin_map)
target_link_libraries(objc-static PRIVATE "$<BUILD_INTERFACE:tsl::robin_map>")
target_include_directories(
objc-static
INTERFACE
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
$<INSTALL_INTERFACE:include>)
set_target_properties(objc-static PROPERTIES
POSITION_INDEPENDENT_CODE true
OUTPUT_NAME ${LIBOBJC_NAME})
Expand All @@ -312,7 +347,9 @@ endif ()

# Explicitly link libm, as an implicit dependency of the C++ runtime
if (M_LIBRARY)
target_link_libraries(objc PUBLIC ${M_LIBRARY})
if (BUILD_SHARED_LIBOBJC)
target_link_libraries(objc PUBLIC ${M_LIBRARY})
endif ()
endif ()

# Make weak symbols work on OS X
Expand Down Expand Up @@ -382,11 +419,13 @@ else ()
endif ()
message(STATUS "GNUstep install type set to ${GNUSTEP_INSTALL_TYPE}")

target_include_directories(
objc
INTERFACE
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
$<INSTALL_INTERFACE:include>)
if (BUILD_SHARED_LIBOBJC)
target_include_directories(
objc
INTERFACE
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
$<INSTALL_INTERFACE:include>)
endif ()
install(TARGETS ${INSTALL_TARGETS}
EXPORT libobjcTargets
RUNTIME DESTINATION ${BIN_INSTALL_PATH}
Expand Down