Only flush SharedFunctionInfo optimized code cache when necessary

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index dfcb29b6027aafbdfab53181fecb10d5f52b542c..3451239f555a0cc8a114addb5f9afc11b6c814d8 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9031,14 +9031,52 @@ void SharedFunctionInfo::InstallFromOptimizedCodeMap(JSFunction* function,
 }
 
 
-void SharedFunctionInfo::ClearOptimizedCodeMap(const char* reason) {
+void SharedFunctionInfo::ClearOptimizedCodeMap(Code* optimized_code,
+                                               const char* reason) {
   if (!optimized_code_map()->IsSmi()) {
-    if (FLAG_trace_opt) {
-      PrintF("[clearing optimizing code map (%s) for ", reason);
-      ShortPrint();
-      PrintF("]\n");
+    if (optimized_code == NULL || true) {
+      if (FLAG_trace_opt) {
+        PrintF("[clearing entire optimizing code map (%s) for ", reason);
+        ShortPrint();
+        PrintF("]\n");
+      }
+      set_optimized_code_map(Smi::FromInt(0));
+    } else {
+      int i;
+      bool removed_entry = false;
+      FixedArray* code_map = FixedArray::cast(optimized_code_map());
+      for (i = 0; i < code_map->length(); i += kEntryLength) {
+        ASSERT(code_map->get(i)->IsNativeContext());
+        if (Code::cast(code_map->get(i + 1)) == optimized_code) {
+          if (FLAG_trace_opt) {
+            PrintF("[clearing optimizing code map (%s) for ", reason);
+            ShortPrint();
+            PrintF("]\n");
+          }
+          removed_entry = true;
+          break;
+        }
+      }
+      while (i < (code_map->length() - kEntryLength)) {
+        code_map->set(i, code_map->get(i + 1 + kEntryLength));
+        code_map->set(i + 1, code_map->get(i + 2 + kEntryLength));
+        code_map->set(i + 2, code_map->get(i + 3 + kEntryLength));
+        i += kEntryLength;
+      }
+      if (removed_entry) {
+        Heap* heap = GetHeap();
+        int new_length = code_map->length() - kEntryLength;
+        if (new_length == 0) {
+          set_optimized_code_map(Smi::FromInt(0));
+          return;
+        }
+        Address filler_start = reinterpret_cast<Address>(
+            code_map->GetFirstElementAddress() + new_length);
+        heap->CreateFillerObjectAt(filler_start,
+                                   kEntryLength * kPointerSize);
+        code_map->set_length(new_length);
+      }
     }
-    set_optimized_code_map(Smi::FromInt(0));
   }
 }