Merge pull request #11010 from aschwaighofer/remove_dead_cow_existential_config_code

Cleanup dead configuration code for copy-on-write existentials

Author: aschwaighofer

cmake/modules/AddSwift.cmake

@@ -265,10 +265,6 @@ function(_add_variant_c_compile_flags)
         "-I${SWIFT_ANDROID_NDK_PATH}/sources/android/support/include")
   endif()
 
-  if(SWIFT_RUNTIME_ENABLE_COW_EXISTENTIALS)
-    list(APPEND result "-DSWIFT_RUNTIME_ENABLE_COW_EXISTENTIALS=1")
-  endif()
-
   set("${CFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
 endfunction()
 

include/swift/Option/FrontendOptions.td

@@ -286,9 +286,6 @@ def disable_deserialization_recovery :
   Flag<["-"], "disable-deserialization-recovery">,
   HelpText<"Don't attempt to recover from missing xrefs (etc) in swiftmodules">;
 
-def enable_cow_existentials : Flag<["-"], "enable-cow-existentials">,
-  HelpText<"Enable the copy-on-write existential implementation">;
-
 def disable_availability_checking : Flag<["-"],
   "disable-availability-checking">,
   HelpText<"Disable checking for potentially unavailable APIs">;

test/IRGen/existentials_opaque_boxed.sil

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-cow-existentials -assume-parsing-unqualified-ownership-sil %s -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend -assume-parsing-unqualified-ownership-sil %s -emit-ir | %FileCheck %s
 
 sil_stage canonical
 

utils/build-script-impl

@@ -252,7 +252,6 @@ KNOWN_SETTINGS=(
     coverage-db                        ""        "If set, coverage database to use when prioritizing testing"
     build-toolchain-only               ""        "If set, only build the necessary tools to build an external toolchain"
     skip-local-host-install            ""        "If we are cross-compiling multiple targets, skip an install pass locally if the hosts match"
-    swift-runtime-enable-cow-existentials "1"    "Enable the copy-on-write existential implementation"
 )
 
 # Centralized access point for traced command invocation.