1 files changed, 22 insertions, 8 deletions
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 75a219a4370..0390d81263a 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -336,20 +336,34 @@ bool Decl::isReferenced() const {
 static AvailabilityResult CheckAvailability(ASTContext &Context,
                                             const AvailabilityAttr *A,
                                             std::string *Message) {
-  StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
-  StringRef PrettyPlatformName
-    = AvailabilityAttr::getPrettyPlatformName(TargetPlatform);
-  if (PrettyPlatformName.empty())
-    PrettyPlatformName = TargetPlatform;
+  VersionTuple TargetMinVersion =
+    Context.getTargetInfo().getPlatformMinVersion();
 
-  VersionTuple TargetMinVersion = Context.getTargetInfo().getPlatformMinVersion();
   if (TargetMinVersion.empty())
     return AR_Available;
 
+  // Check if this is an App Extension "platform", and if so chop off
+  // the suffix for matching with the actual platform.
+  StringRef ActualPlatform = A->getPlatform()->getName();
+  StringRef RealizedPlatform = ActualPlatform;
+  if (Context.getLangOpts().AppExt) {
+    size_t suffix = RealizedPlatform.rfind("_app_extension");
+    if (suffix != StringRef::npos)
+      RealizedPlatform = RealizedPlatform.slice(0, suffix);
+  }
+
+  StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
+
   // Match the platform name.
-  if (A->getPlatform()->getName() != TargetPlatform)
+  if (RealizedPlatform != TargetPlatform)
     return AR_Available;
-  
+
+  StringRef PrettyPlatformName
+    = AvailabilityAttr::getPrettyPlatformName(ActualPlatform);
+
+  if (PrettyPlatformName.empty())
+    PrettyPlatformName = ActualPlatform;
+
   std::string HintMessage;
   if (!A->getMessage().empty()) {
     HintMessage = " - ";