Extend and test install_name symbols for back-deployed concurrency.

With these magic symbols, programs that link against the _Concurrency
module with a deployment target prior to iOS 15 / macOS 12 / watchOS 8
will reference `libswift_Concurrency.dylib` via rpath.

Fixes rdar://81187835.

Author: DougGregor

stdlib/public/Concurrency/linker-support/magic-symbols-for-install-name.c

@@ -40,6 +40,20 @@
 
 #if TARGET_OS_WATCH
   // Check watchOS first, because TARGET_OS_IPHONE includes watchOS.
+  RPATH_INSTALL_NAME_DIRECTIVE( 2, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 2, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 2, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE( 3, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 3, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 3, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE( 4, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 4, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 4, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE( 4, 3)
+  RPATH_INSTALL_NAME_DIRECTIVE( 5, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 5, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 5, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE( 5, 3)
   RPATH_INSTALL_NAME_DIRECTIVE( 6, 0)
   RPATH_INSTALL_NAME_DIRECTIVE( 6, 1)
   RPATH_INSTALL_NAME_DIRECTIVE( 6, 2)
@@ -52,6 +66,32 @@
   RPATH_INSTALL_NAME_DIRECTIVE( 7, 5)
   RPATH_INSTALL_NAME_DIRECTIVE( 7, 6)
 #elif TARGET_OS_IPHONE
+  RPATH_INSTALL_NAME_DIRECTIVE( 7, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 7, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 8, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 8, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 8, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE( 8, 3)
+  RPATH_INSTALL_NAME_DIRECTIVE( 8, 4)
+  RPATH_INSTALL_NAME_DIRECTIVE( 9, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE( 9, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE( 9, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE( 9, 3)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 3)
+  RPATH_INSTALL_NAME_DIRECTIVE(11, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE(11, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE(11, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE(11, 3)
+  RPATH_INSTALL_NAME_DIRECTIVE(11, 4)
+  RPATH_INSTALL_NAME_DIRECTIVE(12, 0)
+  RPATH_INSTALL_NAME_DIRECTIVE(12, 1)
+  RPATH_INSTALL_NAME_DIRECTIVE(12, 2)
+  RPATH_INSTALL_NAME_DIRECTIVE(12, 3)
+  RPATH_INSTALL_NAME_DIRECTIVE(12, 4)
+  RPATH_INSTALL_NAME_DIRECTIVE(12, 5)
   RPATH_INSTALL_NAME_DIRECTIVE(13, 0)
   RPATH_INSTALL_NAME_DIRECTIVE(13, 1)
   RPATH_INSTALL_NAME_DIRECTIVE(13, 2)
@@ -68,14 +108,22 @@
   RPATH_INSTALL_NAME_DIRECTIVE(14, 5)
   RPATH_INSTALL_NAME_DIRECTIVE(14, 6)
   RPATH_INSTALL_NAME_DIRECTIVE(14, 7)
+  RPATH_INSTALL_NAME_DIRECTIVE(14, 8)
 #elif TARGET_OS_OSX
+  RPATH_INSTALL_NAME_DIRECTIVE(10,  9)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 10)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 11)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 12)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 13)
   RPATH_INSTALL_NAME_DIRECTIVE(10, 15)
+  RPATH_INSTALL_NAME_DIRECTIVE(10, 14)
   RPATH_INSTALL_NAME_DIRECTIVE(11,  0)
   RPATH_INSTALL_NAME_DIRECTIVE(11,  1)
   RPATH_INSTALL_NAME_DIRECTIVE(11,  2)
   RPATH_INSTALL_NAME_DIRECTIVE(11,  3)
   RPATH_INSTALL_NAME_DIRECTIVE(11,  4)
   RPATH_INSTALL_NAME_DIRECTIVE(11,  5)
+  RPATH_INSTALL_NAME_DIRECTIVE(11,  6)
 #else
   #error Unknown target.
 #endif

test/Concurrency/Backdeploy/linking.swift

@@ -0,0 +1,21 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -target x86_64-apple-macosx12 %s -o %t/linking_direct
+// RUN: %target-build-swift -target x86_64-apple-macosx11 %s -o %t/linking_rpath
+// RUN: %target-build-swift -target x86_64-apple-macosx10.10 %s -o %t/linking_rpath_old
+
+// RUN: otool -L %t/linking_direct | %FileCheck -check-prefix CHECK-DIRECT %s
+// RUN: otool -L %t/linking_rpath | %FileCheck -check-prefix CHECK-RPATH %s
+// RUN: otool -L %t/linking_rpath_old | %FileCheck -check-prefix CHECK-RPATH %s
+
+// REQUIRES: OS=macosx
+
+// CHECK-DIRECT: /usr/lib/swift/libswift_Concurrency.dylib
+// CHECK-RPATH: @rpath/libswift_Concurrency.dylib
+
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+public struct X {
+  public func f() async -> Int { return 0 }
+  public func g() async -> Int {
+    await f()
+  }
+}