Annotate with merged library name when available

Summary: The "library" annotation contains the target name of the JNI entry point. However, in release builds where merging is enabled, it'll be helpful to also log the name of the merged library where individual targets end up.

Differential Revision: D53900880

fbshipit-source-id: 6f81342c2da9b299e3a2851ab6103da351eaae40

java/com/facebook/soloader/SoLoader.java

@@ -778,10 +778,10 @@ public static boolean loadLibrary(String shortName, int loadFlags) throws Unsati
   @SuppressLint({"CatchGeneralException", "EmptyCatchBlock"})
   private static boolean loadLibraryOnAndroid(String shortName, int loadFlags) {
     @Nullable Throwable failure = null;
-    ObserverHolder.onLoadLibraryStart(shortName, loadFlags);
     try {
       String mergedLibName = MergedSoMapping.mapLibName(shortName);
       String soName = mergedLibName != null ? mergedLibName : shortName;
+      ObserverHolder.onLoadLibraryStart(shortName, mergedLibName, loadFlags);
       return loadLibraryBySoName(
           System.mapLibraryName(soName), shortName, mergedLibName, loadFlags, null);
     } catch (Throwable t) {

java/com/facebook/soloader/observer/Observer.java

@@ -22,7 +22,7 @@
 import javax.annotation.Nullable;
 
 public interface Observer {
-  void onLoadLibraryStart(String library, int flags);
+  void onLoadLibraryStart(String library, @Nullable String mergedLibrary, int flags);
 
   void onLoadLibraryEnd(@Nullable Throwable t);
 

java/com/facebook/soloader/observer/ObserverHolder.java

@@ -45,11 +45,11 @@ public static void addObserver(Observer newObserver) {
     } while (!sObservers.compareAndSet(oldObservers, newObservers));
   }
 
-  public static void onLoadLibraryStart(String library, int flags) {
+  public static void onLoadLibraryStart(String library, @Nullable String mergedLibrary, int flags) {
     Observer[] observers = sObservers.get();
     if (observers != null) {
       for (Observer observer : observers) {
-        observer.onLoadLibraryStart(library, flags);
+        observer.onLoadLibraryStart(library, mergedLibrary, flags);
       }
     }
   }