Merge pull request swiftlang#32856 from nkcsgexi/65488510

ModuleInterface: teach the compiler to look into SDK-versioned prebuilt module cache dir

Author: nkcsgexi

lib/Frontend/CompilerInvocation.cpp

@@ -88,6 +88,20 @@ void CompilerInvocation::setDefaultPrebuiltCacheIfNecessary() {
     platform = getPlatformNameForTriple(LangOpts.Target);
   }
   llvm::sys::path::append(defaultPrebuiltPath, platform, "prebuilt-modules");
+
+  // If the SDK version is given, we should check if SDK-versioned prebuilt
+  // module cache is available and use it if so.
+  if (auto ver = LangOpts.SDKVersion) {
+    // "../macosx/prebuilt-modules"
+    SmallString<64> defaultPrebuiltPathWithSDKVer = defaultPrebuiltPath;
+    // "../macosx/prebuilt-modules/10.15"
+    llvm::sys::path::append(defaultPrebuiltPathWithSDKVer, ver->getAsString());
+    // If the versioned prebuilt module cache exists in the disk, use it.
+    if (llvm::sys::fs::exists(defaultPrebuiltPathWithSDKVer)) {
+      FrontendOpts.PrebuiltModuleCachePath = defaultPrebuiltPathWithSDKVer.str();
+      return;
+    }
+  }
   FrontendOpts.PrebuiltModuleCachePath = defaultPrebuiltPath.str();
 }
 

test/ModuleInterface/default-prebuilt-module-location-sdk-versioned.swift

@@ -0,0 +1,40 @@
+// 1. Create folders for a) our Swift module, b) the module cache, and c) a
+//    fake resource dir with a default prebuilt module cache inside.
+// RUN: %empty-directory(%t/PrebuiltModule.swiftmodule)
+// RUN: %empty-directory(%t/ModuleCache)
+// RUN: %empty-directory(%t/ResourceDir/%target-sdk-name/prebuilt-modules/10.15/PrebuiltModule.swiftmodule)
+// RUN: %empty-directory(%t/ResourceDir/%target-sdk-name/prebuilt-modules/PrebuiltModule.swiftmodule)
+
+// 2. Define some public API
+// RUN: echo 'public struct InPrebuiltModule {}' > %t/PrebuiltModule.swift
+
+// 3. Compile this into a module and put it into the default SKD-versioned prebuilt cache
+//    location relative to the fake resource dir. Also drop an interface into
+//    the build dir.
+// RUN: %target-swift-frontend -emit-module %t/PrebuiltModule.swift -o %t/ResourceDir/%target-sdk-name/prebuilt-modules/10.15/PrebuiltModule.swiftmodule/%target-swiftmodule-name -module-name PrebuiltModule -parse-stdlib -emit-module-interface-path %t/PrebuiltModule.swiftmodule/%target-swiftinterface-name
+
+// 4. Compile this into a module and put it into the default non-versioned prebuilt cache
+//    location relative to the fake resource dir. Also drop an interface into
+//    the build dir.
+// RUN: %target-swift-frontend -emit-module %t/PrebuiltModule.swift -o %t/ResourceDir/%target-sdk-name/prebuilt-modules/PrebuiltModule.swiftmodule/%target-swiftmodule-name -module-name PrebuiltModule -parse-stdlib -emit-module-interface-path %t/PrebuiltModule.swiftmodule/%target-swiftinterface-name
+
+// 5. Import this prebuilt module, but DON'T pass in -prebuilt-module-cache-path, it should use the implicit one from the SDK-versioned prebuilt module cache dir.
+// RUN: %target-swift-frontend -typecheck -resource-dir %t/ResourceDir -I %t %s -parse-stdlib -module-cache-path %t/ModuleCache -sdk %t -target-sdk-version 10.15
+
+// 6. Make sure we installed a forwarding module in the module cache.
+// RUN: %{python} %S/ModuleCache/Inputs/check-is-forwarding-module.py %t/ModuleCache/PrebuiltModule-*.swiftmodule
+
+// 7. Remove the prebuilt module from the SDK-versioned prebuilt module cache dir.
+// RUN: %empty-directory(%t/ResourceDir/%target-sdk-name/prebuilt-modules/10.15)
+
+// 8. Import this prebuilt module, it should not find the prebuilt module cache.
+// RUN: %target-swift-frontend -typecheck -resource-dir %t/ResourceDir -I %t %s -parse-stdlib -module-cache-path %t/ModuleCache -sdk %t -target-sdk-version 10.15
+
+// 9. Make sure we built a binary module in the module cache.
+// RUN: not %{python} %S/ModuleCache/Inputs/check-is-forwarding-module.py %t/ModuleCache/PrebuiltModule-*.swiftmodule
+
+import PrebuiltModule
+
+func x<T>(_ x: T) {}
+
+x(InPrebuiltModule.self)