Only flush SharedFunctionInfo optimized code cache when necessary

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 9016 matching lines @@
   Code* code = Code::cast(code_map->get(index));
   ASSERT(code != NULL);
   ASSERT(function->context()->native_context() == code_map->get(index - 1));
   function->ReplaceCode(code);
 }
 
 
 void SharedFunctionInfo::ClearOptimizedCodeMap(const char* reason) {
   if (!optimized_code_map()->IsSmi()) {
     if (FLAG_trace_opt) {
-      PrintF("[clearing optimizing code map (%s) for ", reason);
+      PrintF("[clearing entire optimizing code map (%s) for ", reason);
       ShortPrint();
       PrintF("]\n");
     }
     set_optimized_code_map(Smi::FromInt(0));
   }
 }
 
 
+void SharedFunctionInfo::EvictFromOptimizedCodeMap(Code* optimized_code,
+                                                   const char* reason) {
+  if (optimized_code_map()->IsSmi()) return;
+
+  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));

[Michael Starzinger, 2013/05/13 14:26:46]

The indices look suspiciously off in this loop!

[danno, 2013/05/13 15:23:10]

Done.

+    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) {
+      ClearOptimizedCodeMap(reason);
+      return;
+    }
+    Address filler_start = reinterpret_cast<Address>(
+        code_map->GetFirstElementAddress() + new_length);
+    heap->CreateFillerObjectAt(filler_start,

[Michael Starzinger, 2013/05/13 14:26:46]

This will destroy live-bytes count if incremental marking is active. Please use
the RightTrimFixedArray helper instead to do the trimming.

[danno, 2013/05/13 15:23:10]

Done.

[danno, 2013/05/13 15:23:10]

Oh, this is much better! Thanks!
On 2013/05/13 14:26:46, Michael Starzinger wrote:

+                               kEntryLength * kPointerSize);
+    code_map->set_length(new_length);
+  }
+}
+
+
 bool JSFunction::CompileLazy(Handle<JSFunction> function,
                              ClearExceptionFlag flag) {
   bool result = true;
   if (function->shared()->is_compiled()) {
     function->ReplaceCode(function->shared()->code());
     function->shared()->set_code_age(0);
   } else {
     ASSERT(function->shared()->allows_lazy_compilation());
     CompilationInfoWithZone info(function);
     result = CompileLazyHelper(&info, flag);
@@ skipping 6298 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal