Add plugin dependencies just once.

Author: rxwei

lib/Frontend/Frontend.cpp

@@ -386,6 +386,11 @@ void CompilerInstance::setupDependencyTrackerIfNeeded() {
     return;
 
   DepTracker = std::make_unique<DependencyTracker>(*collectionMode);
+
+  // Collect compiler plugin dependencies.
+  auto &searchPathOpts = Invocation.getSearchPathOptions();
+  for (auto &path : searchPathOpts.getCompilerPluginLibraryPaths())
+    DepTracker->addDependency(path, /*isSystem=*/false);
 }
 
 bool CompilerInstance::setup(const CompilerInvocation &Invoke,

lib/Serialization/SerializedModuleLoader.cpp

@@ -1256,25 +1256,18 @@ SerializedModuleLoaderBase::loadModule(SourceLoc importLoc,
     M->setFailedToLoad();
   }
 
-  if (dependencyTracker) {
-    if (file) {
-      auto DepPath = file->getFilename();
-      // Don't record cached artifacts as dependencies.
-      if (!isCached(DepPath)) {
-        if (M->hasIncrementalInfo()) {
-          dependencyTracker->addIncrementalDependency(DepPath,
-                                                      M->getFingerprint());
-        } else {
-          dependencyTracker->addDependency(DepPath, /*isSystem=*/false);
-        }
+  if (dependencyTracker && file) {
+    auto DepPath = file->getFilename();
+    // Don't record cached artifacts as dependencies.
+    if (!isCached(DepPath)) {
+      if (M->hasIncrementalInfo()) {
+        dependencyTracker->addIncrementalDependency(DepPath,
+                                                    M->getFingerprint());
+      } else {
+        dependencyTracker->addDependency(DepPath, /*isSystem=*/false);
       }
     }
-    // Collect compiler plugin dependencies.
-    for (auto &path : Ctx.SearchPathOpts.getCompilerPluginLibraryPaths()) {
-      dependencyTracker->addDependency(path, /*isSystem=*/false);
-    }
   }
-
   return M;
 }