[embedded] Start building Synchronization in embedded Swift mode

docs/EmbeddedSwift/EmbeddedSwiftStatus.md

@@ -48,6 +48,7 @@ This status table describes which of the following Swift features can be used in
 
 | **Swift Feature**                                          | **Currently Supported In Embedded Swift?**          |
 |------------------------------------------------------------|-----------------------------------------------------|
+| Synchronization module                                     | Yes    |
 | Swift Concurrency                                          | Partial, experimental (basics of actors and tasks work in single-threaded concurrency mode) |
 | C interop                                                  | Yes    | 
 | C++ interop                                                | Yes    |

docs/EmbeddedSwift/UserManual.md

@@ -197,6 +197,7 @@ For (2), external dependencies are also triggered by specific code needing them,
 - **atomics instrinsics**
   - on CPU architectures that don't have direct load-acquire/store-release support in the ISA, LLVM calls helper functions for atomic operations
   - needed by refcounting in the Embedded Swift runtime (so any class usage will trigger this dependency)
+  - also needed when using atomics from the Synchronization module
 - **multiplication/division/modulo instrinsics**
   - on CPU architectures that don't have direct support for the math operations in the ISA
   - dependency (on Mach-O): `__divti3`

stdlib/public/CMakeLists.txt

@@ -206,8 +206,8 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
       "x86_64  x86_64-unknown-none-elf     x86_64-unknown-none-elf"
       # Without specifying the `windows` component LLVM refuses to
       # generate valid COFF object files.
-      "i686    i686-unknown-windows-coff   i686-unknown-windows-coff"
-      "x86_64  x86_64-unknown-windows-coff x86_64-unknown-windows-coff"
+      "i686    i686-unknown-windows-msvc   i686-unknown-windows-msvc"
+      "x86_64  x86_64-unknown-windows-msvc x86_64-unknown-windows-msvc"
     )
   endif()
 

stdlib/public/Synchronization/AtomicMemoryOrderings.swift

@@ -96,6 +96,7 @@ extension AtomicLoadOrdering: Hashable {
 }
 
 @available(SwiftStdlib 6.0, *)
+@_unavailableInEmbedded
 extension AtomicLoadOrdering: CustomStringConvertible {
   @available(SwiftStdlib 6.0, *)
   public var description: String {
@@ -191,6 +192,7 @@ extension AtomicStoreOrdering: Hashable {
 }
 
 @available(SwiftStdlib 6.0, *)
+@_unavailableInEmbedded
 extension AtomicStoreOrdering: CustomStringConvertible {
   @available(SwiftStdlib 6.0, *)
   public var description: String {
@@ -315,6 +317,7 @@ extension AtomicUpdateOrdering: Hashable {
 }
 
 @available(SwiftStdlib 6.0, *)
+@_unavailableInEmbedded
 extension AtomicUpdateOrdering: CustomStringConvertible {
   @available(SwiftStdlib 6.0, *)
   public var description: String {

stdlib/public/Synchronization/CMakeLists.txt

@@ -10,8 +10,7 @@
 #
 #===----------------------------------------------------------------------===#
 
-add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
-# List of files here:
+set(swift_synchronization_sources
   Atomic.swift
   AtomicBool.swift
   AtomicFloats.swift
@@ -21,23 +20,67 @@ add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
   AtomicPointers.swift
   AtomicRepresentable.swift
   WordPair.swift
+)
+set(swift_synchronization_gyb_sources
+  AtomicIntegers.swift.gyb
+  AtomicStorage.swift.gyb
+)
+set(swift_synchronization_swift_compile_flags
+  ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+  "-enable-builtin-module"
+  "-enable-experimental-feature" "RawLayout"
+  "-enable-experimental-feature" "StaticExclusiveOnly"
+)
 
-  GYB_SOURCES
-    AtomicIntegers.swift.gyb
-    AtomicStorage.swift.gyb
-
-  SWIFT_COMPILE_FLAGS
-    ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
-    "-enable-builtin-module"
-    "-enable-experimental-feature" "RawLayout"
-    "-enable-experimental-feature" "StaticExclusiveOnly"
-
+add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
+  ${swift_synchronization_sources}
+  GYB_SOURCES ${swift_synchronization_gyb_sources}
+  SWIFT_COMPILE_FLAGS ${swift_synchronization_swift_compile_flags}
   LINK_FLAGS
     "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
-
   INSTALL_IN_COMPONENT
     stdlib
-
   MACCATALYST_BUILD_FLAVOR
     "zippered"
 )
+
+# Embedded Synchronization - embedded libraries are built as .swiftmodule only,
+# i.e. there is no .o or .a file produced (no binary code is actually produced)
+# and only users of a library are going to actually compile any needed code.
+if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
+  add_custom_target(embedded-synchronization ALL)
+
+  foreach(entry ${EMBEDDED_STDLIB_TARGET_TRIPLES})
+    string(REGEX REPLACE "[ \t]+" ";" list "${entry}")
+    list(GET list 0 arch)
+    list(GET list 1 mod)
+    list(GET list 2 triple)
+
+    set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${mod}")
+    set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
+    set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
+    set(SWIFT_SDK_embedded_PATH ${SWIFT_SDK_OSX_PATH})
+    set(SWIFT_SDK_embedded_ARCH_${arch}_PATH ${SWIFT_SDK_OSX_PATH})
+    set(SWIFT_SDK_embedded_USE_ISYSROOT TRUE)
+    add_swift_target_library_single(
+      embedded-synchronization-${mod}
+      swiftSynchronization
+      ONLY_SWIFTMODULE
+      IS_FRAGILE
+
+      ${swift_synchronization_sources}
+      GYB_SOURCES ${swift_synchronization_gyb_sources}
+
+      SWIFT_COMPILE_FLAGS
+        ${swift_synchronization_swift_compile_flags}
+        -Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding -enable-experimental-feature Embedded
+
+      MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
+      SDK "embedded"
+      ARCHITECTURE "${arch}"
+      DEPENDS embedded-stdlib-${mod}
+      INSTALL_IN_COMPONENT stdlib
+      )
+    add_dependencies(embedded-synchronization embedded-synchronization-${mod})
+  endforeach()
+endif()

stdlib/public/Synchronization/WordPair.swift

@@ -184,6 +184,7 @@ extension WordPair: Hashable {
 }
 
 @available(SwiftStdlib 6.0, *)
+@_unavailableInEmbedded
 extension WordPair: CustomStringConvertible {
   /// A string that represents the contents of the word pair.
   @available(SwiftStdlib 6.0, *)
@@ -193,6 +194,7 @@ extension WordPair: CustomStringConvertible {
 }
 
 @available(SwiftStdlib 6.0, *)
+@_unavailableInEmbedded
 extension WordPair: CustomDebugStringConvertible {
   /// A string that represents the contents of the word pair, suitable for
   /// debugging.

stdlib/public/core/CMakeLists.txt

@@ -411,9 +411,6 @@ add_swift_target_library(swiftCore
 # Embedded standard library - embedded libraries are built as .swiftmodule only,
 # i.e. there is no .o or .a file produced (no binary code is actually produced)
 # and only users of a library are going to actually compile any needed code.
-#
-# For now, we build a hardcoded list of target triples of the embedded stdlib,
-# and only when building Swift on macOS.
 if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
   add_custom_target(embedded-stdlib ALL)
 

test/embedded/synchronization.swift

@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -parse-as-library -enable-experimental-feature Embedded -disable-availability-checking -c -o %t/main.o
+// RUN: %target-clang %t/main.o -o %t/a.out -dead_strip
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: OS=macosx || OS=linux-gnu
+
+import Synchronization
+
+@main
+struct Main {
+  static let x = Atomic(128)
+
+  static func main() {
+    let old = x.load(ordering: .relaxed)
+    x.store(42, ordering: .relaxed)
+    let new = x.load(ordering: .relaxed)
+    print(old) // CHECK: 128
+    print(new) // CHECK: 42
+    let old2 = x.exchange(12, ordering: .acquiring)
+    print(old2) // CHECK: 42
+    let (exchanged, original) = x.compareExchange(expected: 128, desired: 316, ordering: .sequentiallyConsistent)
+    print(exchanged) // CHECK: false
+    print(original) // CHECK: 12
+    let (exchanged2, original2) = x.compareExchange(expected: 12, desired: 316, ordering: .sequentiallyConsistent)
+    print(exchanged2) // CHECK: true
+    print(original2) // CHECK: 12
+  }
+}