Optimize virtual calls.

jit/baseline.ts

@@ -873,21 +873,24 @@ module J2ME {
         var object = this.pop(Kind.Reference);
         this.emitNullPointerCheck(object);
         args.unshift(object);
-        var objClass = "CI[i32[(" + object + "+" + Constants.OBJ_CLASS_ID_OFFSET + ")>>2]]";
         if (opcode === Bytecodes.INVOKESPECIAL) {
           methodId = methodInfo.id;
+          call = "(LM[" + methodId + "]||" + "GLM(" + methodId + "))(" + args.join(",") + ")";
         } else if (opcode === Bytecodes.INVOKEVIRTUAL) {
-          methodId = objClass + ".vTable[" + methodInfo.vTableIndex + "].id";
+          var classId = "i32[(" + object + "|0)>>2]";
+          call = "(VT[" + classId + "][" + methodInfo.vTableIndex + "]||" + "GLVM(" + classId + "," + methodInfo.vTableIndex + "))(" + args.join(",") + ")";
         } else if (opcode === Bytecodes.INVOKEINTERFACE) {
+          var objClass = "CI[i32[(" + object + "+" + Constants.OBJ_CLASS_ID_OFFSET + ")>>2]]";
           methodId = objClass + ".iTable['" + methodInfo.mangledName + "'].id";
+          call = "(LM[" + methodId + "]||" + "GLM(" + methodId + "))(" + args.join(",") + ")";
         } else {
           Debug.unexpected(Bytecodes[opcode]);
         }
       } else {
         args.unshift(String(Constants.NULL));
         methodId = methodInfo.id;
+        call = "(LM[" + methodId + "]||" + "GLM(" + methodId + "))(" + args.join(",") + ")";
       }
-      call = "(LM[" + methodId + "]||" + "GLM(" + methodId + "))(" + args.join(",") + ")";
 
       if (methodInfo.implKey in inlineMethods) {
         emitDebugInfoComments && this.blockEmitter.writeLn("// Inlining: " + methodInfo.implKey);

utilities.ts

@@ -174,7 +174,7 @@ module J2ME {
      * to dictionary mode. I've experienced ION bailouts from non-dense new Arrays(), hence this helper
      * method.
      */
-    export function makeDenseArray(length, value) {
+    export function makeDenseArray(length: number, value) {
       var array = new Array(length);
       for (var i = 0; i < length; i++) {
         array[i] = value;

vm/parser.ts

@@ -1304,6 +1304,9 @@ module J2ME {
           }
         }
       }
+
+      // Pre-allocate linkedVTableMap.
+      classIdToLinkedVTableMap[this.id] = ArrayUtilities.makeDenseArray(this.vTable.length, null);
     }
 
     private buildITable() {

vm/runtime.ts

@@ -681,6 +681,11 @@ module J2ME {
   export var methodIdToMethodInfoMap: Map<number, MethodInfo> = Object.create(null);
   export var linkedMethods: Map<number, Function> = Object.create(null);
 
+  /**
+   * Maps classIds to vTables containing JS functions.
+   */
+  export var classIdToLinkedVTableMap = ArrayUtilities.makeDenseArray(Constants.MAX_CLASS_ID + 1, null);
+
   export function getClassInfo(addr: number) {
     release || assert(addr !== Constants.NULL, "addr !== Constants.NULL");
     release || assert(i32[addr + Constants.OBJ_CLASS_ID_OFFSET >> 2] != 0,
@@ -976,6 +981,10 @@ module J2ME {
     return getLinkedMethod(methodIdToMethodInfoMap[methodId]);
   }
 
+  export function getLinkedVirtualMethodById(classId: number, vTableIndex: number) {
+    return getLinkedMethod(classIdToClassInfoMap[classId].vTable[vTableIndex]);
+  }
+
   function linkMethod(methodInfo: MethodInfo) {
     runtimeCounter && runtimeCounter.count("linkMethod");
     var fn;
@@ -1121,6 +1130,10 @@ module J2ME {
 
     methodInfo.fn = fn;
     linkedMethods[methodInfo.id] = fn;
+
+    if (methodInfo.vTableIndex >= 0) {
+      classIdToLinkedVTableMap[methodInfo.classInfo.id][methodInfo.vTableIndex] = fn;
+    }
   }
 
   /**
@@ -1976,6 +1989,8 @@ var CI = J2ME.classIdToClassInfoMap;
 var MI = J2ME.methodIdToMethodInfoMap;
 var LM = J2ME.linkedMethods;
 var GLM = J2ME.getLinkedMethodById;
+var GLVM = J2ME.getLinkedVirtualMethodById;
+var VT = J2ME.classIdToLinkedVTableMap;
 
 var CIC = J2ME.classInitCheck;
 var GH = J2ME.getHandle;