[Migrator] Add a stub for authored API change list to handle API changes that are not detected automatically. (#9477)

Author: nkcsgexi

include/swift/Migrator/MigratorOptions.h

@@ -44,7 +44,7 @@ struct MigratorOptions {
   std::string DumpMigrationStatesDir = "";
 
   /// If non-empty, use the api change data serialized to this path.
-  std::string APIDigesterDataStorePath = "";
+  std::vector<std::string> APIDigesterDataStorePaths;
 
   bool shouldRunMigrator() const {
     return !(EmitRemapFilePath.empty() && EmitMigratedFilePath.empty() &&

lib/Frontend/CompilerInvocation.cpp

@@ -1629,7 +1629,7 @@ bool ParseMigratorArgs(MigratorOptions &Opts, llvm::Triple &Triple,
   }
 
   if (auto DataPath = Args.getLastArg(OPT_api_diff_data_file)) {
-    Opts.APIDigesterDataStorePath = DataPath->getValue();
+    Opts.APIDigesterDataStorePaths.push_back(DataPath->getValue());
   } else {
     bool Supported = true;
     llvm::SmallString<128> dataPath(ResourcePath);
@@ -1644,8 +1644,14 @@ bool ParseMigratorArgs(MigratorOptions &Opts, llvm::Triple &Triple,
       llvm::sys::path::append(dataPath, "watchos.json");
     else
       Supported = false;
-    if (Supported)
-      Opts.APIDigesterDataStorePath = dataPath.str();
+    if (Supported) {
+      llvm::SmallString<128> authoredDataPath(ResourcePath);
+      llvm::sys::path::append(authoredDataPath, "migrator");
+      llvm::sys::path::append(authoredDataPath, "overlay.json");
+      // Add authored list first to take higher priority.
+      Opts.APIDigesterDataStorePaths.push_back(authoredDataPath.str());
+      Opts.APIDigesterDataStorePaths.push_back(dataPath.str());
+    }
   }
 
   return false;

lib/Migrator/APIDiffMigratorPass.cpp

@@ -283,9 +283,10 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
     : ASTMigratorPass(Editor, SF, Opts) {}
 
   void run() {
-    if (Opts.APIDigesterDataStorePath.empty())
+    if (Opts.APIDigesterDataStorePaths.empty())
       return;
-    DiffStore.addStorePath(Opts.APIDigesterDataStorePath);
+    for (auto Path : Opts.APIDigesterDataStorePaths)
+      DiffStore.addStorePath(Path);
     DiffStore.printIncomingUsr(Opts.DumpUsr);
     walk(SF);
   }

lib/Migrator/CMakeLists.txt

@@ -3,6 +3,7 @@ set(datafiles
   ios.json
   tvos.json
   watchos.json
+  overlay.json
 )
 set(SWIFTLIB_DIR
     "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib/swift")

lib/Migrator/overlay.json

@@ -0,0 +1,2 @@
+[
+]