Add a SWIFT_STDLIB_STABLE_ABI flag to be able to build the stdlib without -enable-library-evolution (#33443)

Author: kubamracek

CMakeLists.txt

@@ -242,10 +242,6 @@ set(SWIFT_NATIVE_CLANG_TOOLS_PATH "" CACHE STRING
 set(SWIFT_NATIVE_SWIFT_TOOLS_PATH "" CACHE STRING
    "Path to the directory that contains Swift tools that are executable on the build machine")
 
-option(SWIFT_ENABLE_MODULE_INTERFACES
-       "Generate .swiftinterface files alongside .swiftmodule files"
-       TRUE)
-
 option(SWIFT_STDLIB_ENABLE_SIB_TARGETS
        "Should we generate sib targets for the stdlib or not?"
        FALSE)

stdlib/CMakeLists.txt

@@ -9,10 +9,43 @@ project(swift-stdlib LANGUAGES C CXX)
 list(APPEND CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
+if("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "OSX")
+  # All Darwin platforms have ABI stability.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "LINUX")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "FREEBSD")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "OPENBSD")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "CYGWIN")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "WINDOWS")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "HAIKU")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "ANDROID")
+  # TODO(mracek): This should get turned off, as this is not an ABI stable platform.
+  set(SWIFT_STDLIB_STABLE_ABI_default TRUE)
+else()
+  # Any new platform should have non-stable ABI to start with.
+  set(SWIFT_STDLIB_STABLE_ABI_default FALSE)
+endif()
+
 #
 # User-configurable options for the standard library.
 #
 
+option(SWIFT_STDLIB_STABLE_ABI
+  "Should stdlib be built with stable ABI (library evolution, resilience)."
+  "${SWIFT_STDLIB_STABLE_ABI_default}")
+
 option(SWIFT_ENABLE_COMPATIBILITY_OVERRIDES
   "Support back-deploying compatibility fixes for newer apps running on older runtimes."
   TRUE)
@@ -29,6 +62,10 @@ option(SWIFT_STDLIB_OS_VERSIONING
     "Build stdlib with availability based on OS versions (Darwin only)."
     TRUE)
 
+option(SWIFT_ENABLE_MODULE_INTERFACES
+       "Generate .swiftinterface files alongside .swiftmodule files"
+       "${SWIFT_STDLIB_STABLE_ABI}")
+
 #
 # End of user-configurable options.
 #

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -318,8 +318,11 @@ function(_add_target_variant_c_compile_flags)
     list(APPEND result "-DSWIFT_OBJC_INTEROP=0")
   endif()
 
-  # TODO(mracek): This should get turned off for non-ABI-stable environments.
-  list(APPEND result "-DSWIFT_LIBRARY_EVOLUTION=1")
+  if(SWIFT_STDLIB_STABLE_ABI)
+    list(APPEND result "-DSWIFT_LIBRARY_EVOLUTION=1")
+  else()
+    list(APPEND result "-DSWIFT_LIBRARY_EVOLUTION=0")
+  endif()
 
   if(NOT SWIFT_ENABLE_COMPATIBILITY_OVERRIDES)
     list(APPEND result "-DSWIFT_RUNTIME_NO_COMPATIBILITY_OVERRIDES")

stdlib/cmake/modules/SwiftSource.cmake

@@ -399,8 +399,8 @@ function(_compile_swift_files
     list(APPEND swift_flags "-Xfrontend" "-sil-verify-all")
   endif()
 
-  # The standard library and overlays are always built resiliently.
-  if(SWIFTFILE_IS_STDLIB)
+  # The standard library and overlays are built resiliently when SWIFT_STDLIB_STABLE_ABI=On.
+  if(SWIFTFILE_IS_STDLIB AND SWIFT_STDLIB_STABLE_ABI)
     list(APPEND swift_flags "-enable-library-evolution")
   endif()
 

utils/build-script-impl

@@ -197,6 +197,7 @@ KNOWN_SETTINGS=(
     swift-runtime-macho-no-dyld                   "0"               "whether to build stdlib assuming the runtime environment does not support dynamic modules"
     swift-stdlib-single-threaded-runtime          "0"               "whether to build stdlib as a single-threaded runtime only"
     swift-stdlib-os-versioning                    "1"               "whether to build stdlib with availability based on OS versions (Darwin only)"
+    swift-stdlib-stable-abi                       ""                "should stdlib be built with stable ABI, if not set defaults to true on Darwin, false otherwise"
 
     ## FREESTANDING Stdlib Options
     swift-freestanding-sdk                      ""                "which SDK to use when building the FREESTANDING stdlib"
@@ -1872,6 +1873,13 @@ for host in "${ALL_HOSTS[@]}"; do
                     )
                 fi
 
+                if [[ "${SWIFT_STDLIB_STABLE_ABI}" ]] ; then
+                    cmake_options=(
+                        "${cmake_options[@]}"
+                        -DSWIFT_STDLIB_STABLE_ABI:BOOL=$(true_false "${SWIFT_STDLIB_STABLE_ABI}")
+                    )
+                fi
+
                 if [ "${SWIFT_INSTALL_COMPONENTS}" ] ; then
                     cmake_options=(
                         "${cmake_options[@]}"