Add plugin dependencies just once.

Author: rxwei

include/swift/AST/ModuleLoader.h

@@ -185,7 +185,7 @@ class ModuleLoader {
 
 protected:
   DependencyTracker * const dependencyTracker;
-  ModuleLoader(DependencyTracker *tracker) : dependencyTracker(tracker) {}
+  ModuleLoader(ASTContext &ctx, DependencyTracker *tracker);
 
 public:
   virtual ~ModuleLoader() = default;

include/swift/Sema/SourceLoader.h

@@ -29,7 +29,7 @@ class SourceLoader : public ModuleLoader {
   explicit SourceLoader(ASTContext &ctx,
                         bool enableResilience,
                         DependencyTracker *tracker)
-    : ModuleLoader(tracker), Ctx(ctx),
+    : ModuleLoader(ctx, tracker), Ctx(ctx),
       EnableLibraryEvolution(enableResilience) {}
 
 public:

lib/AST/ModuleLoader.cpp

@@ -74,6 +74,14 @@ DependencyTracker::getClangCollector() {
   return clangCollector;
 }
 
+ModuleLoader::ModuleLoader(ASTContext &ctx, DependencyTracker *tracker)
+    : dependencyTracker(tracker) {
+  // Collect compiler plugin dependencies.
+  if (tracker)
+    for (auto &path : ctx.SearchPathOpts.getCompilerPluginLibraryPaths())
+      dependencyTracker->addDependency(path, /*isSystem=*/false);
+}
+
 static bool findOverlayFilesInDirectory(ASTContext &ctx, StringRef path,
                                         StringRef moduleName,
                                         SourceLoc diagLoc,

lib/Serialization/SerializedModuleLoader.cpp

@@ -125,7 +125,7 @@ Optional<bool> forEachModuleSearchPath(
 SerializedModuleLoaderBase::SerializedModuleLoaderBase(
     ASTContext &ctx, DependencyTracker *tracker, ModuleLoadingMode loadMode,
     bool IgnoreSwiftSourceInfoFile)
-    : ModuleLoader(tracker), Ctx(ctx), LoadMode(loadMode),
+    : ModuleLoader(ctx, tracker), Ctx(ctx), LoadMode(loadMode),
       IgnoreSwiftSourceInfoFile(IgnoreSwiftSourceInfoFile) {}
 
 SerializedModuleLoaderBase::~SerializedModuleLoaderBase() = default;
@@ -1256,23 +1256,17 @@ 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;