Availability: only diagnose exposing SPI_AVAILABLE symbols in modules with library-level=API

For executable targets or private libraries, using SPI_AVAILABLE symbols should be allowed.

rdar://91088241

lib/Sema/TypeCheckAccess.cpp

@@ -1546,13 +1546,21 @@ swift::getDisallowedOriginKind(const Decl *decl,
     // Implementation-only imported, cannot be reexported.
     return DisallowedOriginKind::ImplementationOnly;
   } else if ((decl->isSPI() || decl->isAvailableAsSPI()) && !where.isSPI()) {
-    // Allowing unavailable context to use @_spi_available decls.
+    if (decl->isAvailableAsSPI() && !decl->isSPI()) {
-    // Decls with @_spi_available aren't hidden entirely from public interfaces,
+      // Allowing unavailable context to use @_spi_available decls.
-    // thus public interfaces may still refer them. Be forgiving here so public
+      // Decls with @_spi_available aren't hidden entirely from public interfaces,
-    // interfaces can compile.
+      // thus public interfaces may still refer them. Be forgiving here so public
-    if (where.getUnavailablePlatformKind().hasValue() &&
+      // interfaces can compile.
-        decl->isAvailableAsSPI() && !decl->isSPI()) {
+      if (where.getUnavailablePlatformKind().hasValue())
-      return DisallowedOriginKind::None;
+        return DisallowedOriginKind::None;
+      // We should only diagnose SPI_AVAILABLE usage when the library level is API.
+      // Using SPI_AVAILABLE symbols in private frameworks or executable targets
+      // should be allowed.
+      if (auto *mod = where.getDeclContext()->getParentModule()) {
+        if (mod->getLibraryLevel() != LibraryLevel::API) {
+          return DisallowedOriginKind::None;
+        }
+      }
     }
     // SPI can only be exported in SPI.
     return where.getDeclContext()->getParentModule() == M ?

test/ClangImporter/availability_spi_as_unavailable.swift

@@ -1,6 +1,6 @@
 // REQUIRES: OS=macosx
-// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -DNOT_UNDERLYING
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -DNOT_UNDERLYING -library-level api
-// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -module-name SPIContainer -import-underlying-module -verify
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -module-name SPIContainer -import-underlying-module -verify -library-level api
 
 #if NOT_UNDERLYING
 import SPIContainer

test/ClangImporter/availability_spi_as_unavailable_bridging_header.swift

@@ -1,5 +1,5 @@
 // REQUIRES: OS=macosx
-// RUN: %target-swift-frontend -typecheck %s -import-objc-header %S/Inputs/frameworks/SPIContainer.framework/Headers/SPIContainer.h -verify
+// RUN: %target-swift-frontend -typecheck %s -import-objc-header %S/Inputs/frameworks/SPIContainer.framework/Headers/SPIContainer.h -verify -library-level api
 
 
 @_spi(a) public let a: SPIInterface1

test/ClangImporter/availability_spi_library_level_spi.swift

@@ -0,0 +1,35 @@
+// REQUIRES: OS=macosx
+
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -DNOT_UNDERLYING
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -DNOT_UNDERLYING -library-level spi
+
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -module-name SPIContainer -import-underlying-module -verify
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -module-name SPIContainer -import-underlying-module -verify -library-level spi
+
+
+#if NOT_UNDERLYING
+import SPIContainer
+#endif
+
+@_spi(a) public let a: SPIInterface1
+@_spi(a) public let b: SPIInterface2
+
+public let c: SPIInterface1
+public let d: SPIInterface2
+
+@inlinable
+public func inlinableUsingSPI() {
+  SharedInterface.foo()
+}
+
+@available(macOS, unavailable)
+public let e: SPIInterface2
+
+@available(iOS, unavailable)
+public let f: SPIInterface2
+
+@inlinable
+@available(macOS, unavailable)
+public func inlinableUnavailableUsingSPI() {
+  SharedInterface.foo()
+}

test/ClangImporter/availability_spi_transitive.swift

@@ -1,5 +1,5 @@
 // REQUIRES: OS=macosx
-// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify
+// RUN: %target-swift-frontend -typecheck %s -F %S/Inputs/frameworks -verify -library-level api
 
 import SPIContainerImporter
 

test/ModuleInterface/spi-available-interface.swift

@@ -1,10 +1,10 @@
 // REQUIRES: OS=macosx
 // RUN: %empty-directory(%t/inputs)
-// RUN: %target-swift-frontend -typecheck %s -F %S/../ClangImporter/Inputs/frameworks -DFoo -emit-module-interface-path %t/inputs/Foo.swiftinterface -module-name Foo -enable-library-evolution -disable-clang-spi
+// RUN: %target-swift-frontend -typecheck %s -F %S/../ClangImporter/Inputs/frameworks -DFoo -emit-module-interface-path %t/inputs/Foo.swiftinterface -module-name Foo -enable-library-evolution -disable-clang-spi -library-level api
 
-// RUN: %target-swift-frontend -typecheck %s -F %S/../ClangImporter/Inputs/frameworks -enable-library-evolution -I %t/inputs -disable-clang-spi
+// RUN: %target-swift-frontend -typecheck %s -F %S/../ClangImporter/Inputs/frameworks -enable-library-evolution -I %t/inputs -disable-clang-spi -library-level api
 
-// RUN: %target-swift-frontend -typecheck-module-from-interface %t/inputs/Foo.swiftinterface -F %S/../ClangImporter/Inputs/frameworks -disable-clang-spi
+// RUN: %target-swift-frontend -typecheck-module-from-interface %t/inputs/Foo.swiftinterface -F %S/../ClangImporter/Inputs/frameworks -disable-clang-spi -library-level api
 
 
 #if Foo

test/Sema/spi-available-inline.swift

@@ -1,6 +1,6 @@
 // REQUIRES: VENDOR=apple
 // REQUIRES: OS=macosx
-// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx11.9
+// RUN: %target-typecheck-verify-swift -target %target-cpu-apple-macosx11.9 -library-level api
 
 @_spi_available(macOS 10.4, *)
 public class MacOSSPIClass { public init() {} }