From 2a367234beb720a63d76707b00d60eec3a762d06 Mon Sep 17 00:00:00 2001
From: Eric Miotto <1094986+edymtt@users.noreply.github.com>
Date: Thu, 6 Feb 2025 09:03:37 -0800
Subject: [PATCH] Runtimes: support generic metadata prespecialization for all
 of Core

Also provide a flag to enabled/disable it.

Addresses rdar://144255917
---
 Runtimes/Core/CMakeLists.txt                      | 4 +++-
 Runtimes/Core/cmake/modules/DefaultSettings.cmake | 3 +++
 Runtimes/Core/core/CMakeLists.txt                 | 3 +--
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Runtimes/Core/CMakeLists.txt b/Runtimes/Core/CMakeLists.txt
index 54c25b0bbb5aa..b642d77926103 100644
--- a/Runtimes/Core/CMakeLists.txt
+++ b/Runtimes/Core/CMakeLists.txt
@@ -106,6 +106,7 @@ option(SwiftCore_HAS_DARWIN_LIBMALLOC "Use Darwin malloc features" ${APPLE})
 defaulted_option(SwiftCore_ENABLE_BACKTRACING "Enable backtracing runtime support")
 defaulted_set(SwiftCore_BACKTRACER_PATH STRING "Set a fixed path to the Swift backtracer")
 defaulted_option(SwiftCore_ENABLE_FATALERROR_BACKTRACE "Build stdlib fatalError with backtrace output")
+defaulted_option(SwiftCore_ENABLE_PRESPECIALIZATION "Enable generic metadata prespecialization")
 
 option(SwiftCore_ENABLE_CLOBBER_FREED_OBJECTS "" OFF)
 option(SwiftCore_ENABLE_RUNTIME_LEAK_CHECKER "" OFF)
@@ -181,7 +182,8 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
   "$<$<AND:$<NOT:$<BOOL:${SwiftCore_ENABLE_OBJC_INTEROP}>>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -disable-objc-interop>"
   "$<$<AND:$<PLATFORM_ID:Windows>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xcc -Xclang -Xcc -fbuiltin-headers-in-system-modules>"
-  "$<$<AND:$<BOOL:${SwiftCore_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>")
+  "$<$<AND:$<BOOL:${SwiftCore_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
+  "$<$<AND:$<BOOL:${SwiftCore_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
 
 include_directories(include)
 
diff --git a/Runtimes/Core/cmake/modules/DefaultSettings.cmake b/Runtimes/Core/cmake/modules/DefaultSettings.cmake
index 29923e5bf5d4c..3c2db77aa30fa 100644
--- a/Runtimes/Core/cmake/modules/DefaultSettings.cmake
+++ b/Runtimes/Core/cmake/modules/DefaultSettings.cmake
@@ -41,6 +41,7 @@ if(APPLE)
   set(SwiftCore_ENABLE_RUNTIME_OS_VERSIONING ON)
   set(SwiftCore_ENABLE_OVERRIDABLE_RETAIN_RELEASE ON)
   set(SwiftCore_THREADING_PACKAGE "DARWIN")
+  set(SwiftCore_ENABLE_PRESPECIALIZATION_default ON)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "WASM")
   set(SwiftCore_OBJECT_FORMAT_default "elf")
   set(SwiftCore_THREADING_PACKAGE "NONE")
@@ -49,6 +50,7 @@ elseif(LINUX OR ANDROID OR BSD)
   set(SwiftCore_ENABLE_FATALERROR_BACKTRACE_default ON)
   if(LINUX)
     set(SwiftCore_THREADING_PACKAGE "LINUX")
+    set(SwiftCore_ENABLE_PRESPECIALIZATION_default ON)
   else()
     set(SwiftCore_THREADING_PACKAGE "PTHREADS")
   endif()
@@ -56,6 +58,7 @@ elseif(WIN32)
   set(SwiftCore_OBJECT_FORMAT_default "coff")
   set(SwiftCore_THREADING_PACKAGE "WIN32")
   set(SwiftCore_ENABLE_FATALERROR_BACKTRACE_default ON)
+  set(SwiftCore_ENABLE_PRESPECIALIZATION_default ON)
 endif()
 
 include("${SwiftCore_VENDOR_MODULE_DIR}/DefaultSettings.cmake" OPTIONAL)
diff --git a/Runtimes/Core/core/CMakeLists.txt b/Runtimes/Core/core/CMakeLists.txt
index 23f9741d2f887..4f5ab2d5c6899 100644
--- a/Runtimes/Core/core/CMakeLists.txt
+++ b/Runtimes/Core/core/CMakeLists.txt
@@ -283,8 +283,7 @@ target_compile_options(swiftCore PRIVATE
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -group-info-path -Xfrontend ${CMAKE_CURRENT_SOURCE_DIR}/GroupInfo.json>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-autolinking-runtime-compatibility-concurrency>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-objc-attr-requires-foundation-module>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -require-explicit-availability=ignore>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -prespecialize-generic-metadata>")
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -require-explicit-availability=ignore>")
 
 if(NOT "${CMAKE_BUILD_TYPE}" STREQUAL "MinSizeRel")
   # Using these in MinSizeRel would result in a 15% increase in the binary size