AST: support availability on Windows

include/swift/AST/PlatformKinds.def

@@ -33,5 +33,6 @@ AVAILABILITY_PLATFORM(macOSApplicationExtension, "application extensions for mac
 AVAILABILITY_PLATFORM(macCatalyst, "Mac Catalyst")
 AVAILABILITY_PLATFORM(macCatalystApplicationExtension, "application extensions for Mac Catalyst")
 AVAILABILITY_PLATFORM(OpenBSD, "OpenBSD")
+AVAILABILITY_PLATFORM(Windows, "Windows")
 
 #undef AVAILABILITY_PLATFORM

lib/AST/PlatformKind.cpp

@@ -89,6 +89,8 @@ static bool isPlatformActiveForTarget(PlatformKind Platform,
       return Target.isWatchOS();
     case PlatformKind::OpenBSD:
       return Target.isOSOpenBSD();
+    case PlatformKind::Windows:
+      return Target.isOSWindows();
     case PlatformKind::none:
       llvm_unreachable("handled above");
   }

lib/ClangImporter/ClangImporter.cpp

@@ -1934,6 +1934,10 @@ PlatformAvailability::PlatformAvailability(const LangOptions &langOpts)
     deprecatedAsUnavailableMessage = "";
     break;
 
+  case PlatformKind::Windows:
+    deprecatedAsUnavailableMessage = "";
+    break;
+
   case PlatformKind::none:
     break;
   }
@@ -1969,6 +1973,9 @@ bool PlatformAvailability::isPlatformRelevant(StringRef name) const {
   case PlatformKind::OpenBSD:
     return name == "openbsd";
 
+  case PlatformKind::Windows:
+    return name == "windows";
+
   case PlatformKind::none:
     return false;
   }
@@ -2012,6 +2019,10 @@ bool PlatformAvailability::treatDeprecatedAsUnavailable(
   case PlatformKind::OpenBSD:
     // No deprecation filter on OpenBSD
     return false;
+
+  case PlatformKind::Windows:
+    // No deprecation filter on Windows
+    return false;
   }
 
   llvm_unreachable("Unexpected platform");

lib/PrintAsObjC/DeclAndTypePrinter.cpp

@@ -881,6 +881,9 @@ class DeclAndTypePrinter::Implementation
       case PlatformKind::OpenBSD:
         plat = "openbsd";
         break;
+      case PlatformKind::Windows:
+        plat = "windows";
+        break;
       case PlatformKind::none:
         llvm_unreachable("handled above");
       }

lib/SymbolGraphGen/AvailabilityMixin.cpp

@@ -58,6 +58,8 @@ StringRef getDomain(const AvailableAttr &AvAttr) {
       return { "watchOSAppExtension" };
     case swift::PlatformKind::OpenBSD:
       return { "OpenBSD" };
+    case swift::PlatformKind::Windows:
+      return { "Windows" };
     case swift::PlatformKind::none:
       return { "*" };
   }

lib/TBDGen/TBDGen.cpp

@@ -251,6 +251,8 @@ getLinkerPlatformId(OriginallyDefinedInAttr::ActiveVersion Ver) {
     llvm_unreachable("cannot find platform kind");
   case swift::PlatformKind::OpenBSD:
     llvm_unreachable("not used for this platform");
+  case swift::PlatformKind::Windows:
+    llvm_unreachable("not used for this platform");
   case swift::PlatformKind::iOS:
   case swift::PlatformKind::iOSApplicationExtension:
     return Ver.IsSimulator ? LinkerPlatformId::iOS_sim:

test/IDE/complete_decl_attribute.swift

@@ -40,6 +40,7 @@ struct MyStruct {}
 // AVAILABILITY1-NEXT: Keyword/None:                       macCatalyst[#Platform#]; name=macCatalyst
 // AVAILABILITY1-NEXT: Keyword/None:                       macCatalystApplicationExtension[#Platform#]; name=macCatalystApplicationExtension
 // AVAILABILITY1-NEXT: Keyword/None:                       OpenBSD[#Platform#]; name=OpenBSD{{$}}
+// AVAILABILITY1-NEXT: Keyword/None:                       Windows[#Platform#]; name=Windows{{$}}
 // AVAILABILITY1-NEXT: End completions
 
 @available(*, #^AVAILABILITY2^#)

test/Parse/diagnose_availability_windows.swift

@@ -0,0 +1,28 @@
+// RUN: %target-typecheck-verify-swift
+// REQUIRES: OS=windows-msvc
+
+// expected-note@+2{{'unavailable()' has been explicitly marked unavailable here}}
+@available(Windows, unavailable, message: "unsupported")
+func unavailable() {}
+
+// expected-error@+1 {{'unavailable()' is unavailable in Windows: unsupported}}
+unavailable()
+
+@available(Windows, introduced: 10.0.17763, deprecated: 10.0.19140)
+func introduced_deprecated() {}
+
+// expected-error@+1 {{'introduced_deprecated()' is only available in * 10.0.17763 or newe}}
+introduced_deprecated()
+// expected-note@-1 {{add 'if #available' version check}}
+
+@available(Windows 10, *)
+func windows10() {}
+
+// expected-error@+1 {{'windows10()' is only available in * 10 or newer}}
+windows10()
+// expected-note@-1 {{add 'if #available' version check}}
+
+func coniditonal_compilation() {
+  if #available(Windows 10, *) {
+  }
+}

tools/SourceKit/lib/SwiftLang/SwiftDocSupport.cpp

@@ -660,6 +660,7 @@ static void reportAttributes(ASTContext &Ctx,
   static UIdent PlatformtvOSAppExt("source.availability.platform.tvos_app_extension");
   static UIdent PlatformWatchOSAppExt("source.availability.platform.watchos_app_extension");
   static UIdent PlatformOpenBSD("source.availability.platform.openbsd");
+  static UIdent PlatformWindows("source.availability.platform.windows");
   std::vector<const DeclAttribute*> Scratch;
 
   for (auto Attr : getDeclAttributes(D, Scratch)) {
@@ -690,6 +691,8 @@ static void reportAttributes(ASTContext &Ctx,
         PlatformUID = PlatformWatchOSAppExt; break;
       case PlatformKind::OpenBSD:
         PlatformUID = PlatformOpenBSD; break;
+      case PlatformKind::Windows:
+        PlatformUID = PlatformWindows; break;
       }
 
       AvailableAttrInfo Info;