Optional .a linkage for libraries

arduino-core/src/processing/app/debug/Compiler.java

@@ -1070,8 +1070,23 @@ private void compileLibrary(UserLibrary lib, List<File> includeFolders)
     if (lib.useRecursion()) {
       // libBuildFolder == {build.path}/LibName
       // libFolder      == {lib.path}/src
-      recursiveCompileFilesInFolder(libBuildFolder, libFolder, includeFolders);
-
+
+      // Compile the library with .a linkage if a flag was set in library.properties
+      if(lib.alinkage()){
+
+        createFolder(libBuildFolder);
+        File afile = compileThroughAFile(libBuildFolder, libFolder, lib.getName(), includeFolders);
+
+        // This is not a .o object file, but a .a file with all .o files inside.
+        // This way libraries can be optimized better, similar as the core files.
+        objectFiles.add(afile);
+      }
+
+      // no alinkage, old, default .o file linkage
+      else{
+        recursiveCompileFilesInFolder(libBuildFolder, libFolder, includeFolders);
+      }
+
     } else {
       // libFolder          == {lib.path}/
       // utilityFolder      == {lib.path}/utility
@@ -1103,39 +1118,17 @@ private void compileFilesInFolder(File buildFolder, File srcFolder, List<File> i
     objectFiles.addAll(objects);
   }
 
-  // 3. compile the core, outputting .o files to <buildPath> and then
-  // collecting them into the core.a library file.
-  // Also compiles the variant (if it supplies actual source files),
-  // which are included in the link directly (not through core.a)
-  void compileCore()
-          throws RunnerException, PreferencesMapException {
-
-    File coreFolder = prefs.getFile("build.core.path");
-    File variantFolder = prefs.getFile("build.variant.path");
-    File buildFolder = new File(prefs.getFile("build.path"), "core");
-    if (!buildFolder.exists() && !buildFolder.mkdirs()) {
-      throw new RunnerException("Unable to create folder " + buildFolder);
-    }
+  private File compileThroughAFile(File buildFolder, File srcFolder, String name, List<File> includeFolders)
+            throws RunnerException, PreferencesMapException {
+    File afile = new File(buildFolder, name + ".a");
 
-    List<File> includeFolders = new ArrayList<File>();
-    includeFolders.add(coreFolder); // include core path only
-    if (variantFolder != null)
-      includeFolders.add(variantFolder);
-
-
-    if (variantFolder != null)
-      objectFiles.addAll(compileFiles(buildFolder, variantFolder, true,
-                                      includeFolders));
-
-    File afile = new File(buildFolder, "core.a");
-
-    List<File> coreObjectFiles = compileFiles(buildFolder, coreFolder, true,
+    List<File> aObjectFiles = compileFiles(buildFolder, srcFolder, true,
                                               includeFolders);
 
     // See if the .a file is already uptodate
     if (afile.exists()) {
       boolean changed = false;
-      for (File file : coreObjectFiles) {
+      for (File file : aObjectFiles) {
         if (file.lastModified() > afile.lastModified()) {
           changed = true;
           break;
@@ -1151,15 +1144,15 @@ void compileCore()
       if (!changed) {
         if (verbose)
           System.out.println(I18n.format(tr("Using previously compiled file: {0}"), afile.getPath()));
-        return;
+        return afile;
       }
     }
 
     // Delete the .a file, to prevent any previous code from lingering
     afile.delete();
 
     try {
-      for (File file : coreObjectFiles) {
+      for (File file : aObjectFiles) {
 
         PreferencesMap dict = new PreferencesMap(prefs);
         dict.put("ide_version", "" + BaseNoGui.REVISION);
@@ -1180,6 +1173,35 @@ void compileCore()
       afile.delete();
       throw e;
     }
+
+    return afile;
+  }
+
+  // 3. compile the core, outputting .o files to <buildPath> and then
+  // collecting them into the core.a library file.
+  // Also compiles the variant (if it supplies actual source files),
+  // which are included in the link directly (not through core.a)
+  void compileCore()
+          throws RunnerException, PreferencesMapException {
+
+    File coreFolder = prefs.getFile("build.core.path");
+    File variantFolder = prefs.getFile("build.variant.path");
+    File buildFolder = new File(prefs.getFile("build.path"), "core");
+    if (!buildFolder.exists() && !buildFolder.mkdirs()) {
+      throw new RunnerException("Unable to create folder " + buildFolder);
+    }
+
+    List<File> includeFolders = new ArrayList<File>();
+    includeFolders.add(coreFolder); // include core path only
+    if (variantFolder != null)
+      includeFolders.add(variantFolder);
+
+
+    if (variantFolder != null)
+      objectFiles.addAll(compileFiles(buildFolder, variantFolder, true,
+                                      includeFolders));
+
+    compileThroughAFile(buildFolder, coreFolder, "core", includeFolders);
   }
 
   // 4. link it all together into the .elf file

arduino-core/src/processing/app/packages/UserLibrary.java

@@ -58,6 +58,7 @@ public class UserLibrary extends ContributedLibrary {
   private List<String> types;
   private List<String> declaredTypes;
   private boolean onGoingDevelopment;
+  private boolean alinkage;
 
   private static final List<String> MANDATORY_PROPERTIES = Arrays
     .asList("name", "version", "author", "maintainer",
@@ -154,6 +155,12 @@ public static UserLibrary create(File libFolder) throws IOException {
       typesList.add(type.trim());
     }
 
+    String alinkageString = properties.get("alinkage");
+    boolean alinkage = false;
+    if(alinkageString != null && alinkageString.equals("true")) {
+      alinkage = true;
+    }
+
     UserLibrary res = new UserLibrary();
     res.setInstalledFolder(libFolder);
     res.setInstalled(true);
@@ -170,6 +177,7 @@ public static UserLibrary create(File libFolder) throws IOException {
     res.layout = layout;
     res.declaredTypes = typesList;
     res.onGoingDevelopment = Files.exists(Paths.get(libFolder.getAbsolutePath(), Constants.LIBRARY_DEVELOPMENT_FLAG_FILE));
+    res.alinkage = alinkage;
     return res;
   }
 
@@ -274,6 +282,10 @@ public boolean onGoingDevelopment() {
     return onGoingDevelopment;
   }
 
+  public boolean alinkage() {
+    return alinkage;
+  }
+
   protected enum LibraryLayout {
     FLAT, RECURSIVE
   }