[Sema] Consider more paths in the SDK as defining private modules

lib/AST/Module.cpp

@@ -2629,26 +2629,35 @@ LibraryLevel
 ModuleLibraryLevelRequest::evaluate(Evaluator &evaluator,
                                     const ModuleDecl *module) const {
   auto &ctx = module->getASTContext();
+  namespace path = llvm::sys::path;
+  SmallString<128> scratch;
+
+  /// Is \p path under the folder SDK/a/b/c/d/e?
+  auto hasSDKPrefix =
+    [&](StringRef path, const Twine &a, const Twine &b = "",
+        const Twine &c = "", const Twine &d = "", const Twine &e = "") {
+    scratch = ctx.SearchPathOpts.getSDKPath();
+    path::append(scratch, a, b, c, d);
+    path::append(scratch, e);
+    return path.startswith(scratch);
+  };
 
   /// Is \p modulePath from System/Library/PrivateFrameworks/?
   auto fromPrivateFrameworks = [&](StringRef modulePath) -> bool {
     if (!ctx.LangOpts.Target.isOSDarwin()) return false;
 
-    namespace path = llvm::sys::path;
-    SmallString<128> scratch;
-    scratch = ctx.SearchPathOpts.getSDKPath();
-    path::append(scratch, "System", "Library", "PrivateFrameworks");
-    return hasPrefix(path::begin(modulePath), path::end(modulePath),
-                     path::begin(scratch), path::end(scratch));
+    return hasSDKPrefix(modulePath, "AppleInternal", "Library", "Frameworks") ||
+           hasSDKPrefix(modulePath, "System", "Library", "PrivateFrameworks") ||
+           hasSDKPrefix(modulePath, "System", "iOSSupport", "System", "Library", "PrivateFrameworks") ||
+           hasSDKPrefix(modulePath, "usr", "local", "include");
   };
 
   if (module->isNonSwiftModule()) {
     if (auto *underlying = module->findUnderlyingClangModule()) {
       // Imported clangmodules are SPI if they are defined by a private
       // modulemap or from the PrivateFrameworks folder in the SDK.
       bool moduleIsSPI = underlying->ModuleMapIsPrivate ||
-                         (underlying->isPartOfFramework() &&
-                          fromPrivateFrameworks(underlying->PresumedModuleMapFile));
+                         fromPrivateFrameworks(underlying->PresumedModuleMapFile);
       return moduleIsSPI ? LibraryLevel::SPI : LibraryLevel::API;
     }
     return LibraryLevel::Other;

test/Sema/Inputs/public-private-sdk/usr/local/include/LocalClang.h

@@ -0,0 +1 @@
+// Empty

test/Sema/Inputs/public-private-sdk/usr/local/include/module.modulemap

@@ -0,0 +1,4 @@
+module LocalClang [system] {
+  header "LocalClang.h"
+  export *
+}

test/Sema/implementation-only-import-suggestion.swift

@@ -11,12 +11,12 @@
 // RUN:   %t/sdk/System/Library/PrivateFrameworks/PrivateSwift.framework/Modules/PrivateSwift.swiftmodule/source.swift \
 // RUN:   -o %t/sdk/System/Library/PrivateFrameworks/PrivateSwift.framework/Modules/PrivateSwift.swiftmodule/%target-swiftmodule-name
 
-/// Expect warnings when building a public client.
+/// Expect errors when building a public client.
 // RUN: %target-swift-frontend -typecheck -sdk %t/sdk -module-cache-path %t %s \
 // RUN:   -F %t/sdk/System/Library/PrivateFrameworks/ \
 // RUN:   -library-level api -verify -D PUBLIC_IMPORTS -module-name MainLib
 
-/// Expect no warnings when building an SPI client.
+/// Expect no errors when building an SPI client.
 // RUN: %target-swift-frontend -typecheck -sdk %t/sdk -module-cache-path %t %s \
 // RUN:   -F %t/sdk/System/Library/PrivateFrameworks/ \
 // RUN:   -library-level spi -D PUBLIC_IMPORTS -module-name MainLib
@@ -26,7 +26,7 @@
 // RUN:   -F %t/sdk/System/Library/PrivateFrameworks/ \
 // RUN:   -library-level spi -D PUBLIC_IMPORTS -module-name MainLib
 
-/// Expect no warnings when building a client with some other library level.
+/// Expect no errors when building a client with some other library level.
 // RUN: %target-swift-frontend -typecheck -sdk %t/sdk -module-cache-path %t %s \
 // RUN:   -F %t/sdk/System/Library/PrivateFrameworks/ \
 // RUN:   -D PUBLIC_IMPORTS -module-name MainLib
@@ -40,9 +40,10 @@ import PrivateSwift // expected-error{{private module 'PrivateSwift' is imported
 import PublicClang
 import PublicClang_Private // expected-error{{private module 'PublicClang_Private' is imported publicly from the public module 'MainLib'}}
 import FullyPrivateClang // expected-error{{private module 'FullyPrivateClang' is imported publicly from the public module 'MainLib'}}
+import LocalClang // expected-error{{private module 'LocalClang' is imported publicly from the public module 'MainLib'}}
 @_exported import MainLib // expected-warning{{private module 'MainLib' is imported publicly from the public module 'MainLib'}}
 
-/// Expect no warnings with implementation-only imports.
+/// Expect no errors with implementation-only imports.
 // RUN: %target-swift-frontend -typecheck -sdk %t/sdk -module-cache-path %t %s \
 // RUN:   -F %t/sdk/System/Library/PrivateFrameworks/ \
 // RUN:   -library-level api -D IMPL_ONLY_IMPORTS
@@ -51,6 +52,7 @@ import FullyPrivateClang // expected-error{{private module 'FullyPrivateClang' i
 @_implementationOnly import PrivateSwift
 @_implementationOnly import PublicClang_Private
 @_implementationOnly import FullyPrivateClang
+@_implementationOnly import LocalClang
 
 #endif