Changing the aging mechanism for script and eval caches.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <sstream>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
@@ skipping 13625 matching lines @@
                   Handle<SharedFunctionInfo> shared,
                   StrictMode strict_mode,
                   int scope_position)
       : source_(source),
         shared_(shared),
         strict_mode_(strict_mode),
         scope_position_(scope_position) { }
 
   bool IsMatch(Object* other) OVERRIDE {
     DisallowHeapAllocation no_allocation;
-    if (!other->IsFixedArray()) return false;
+    if (!other->IsFixedArray()) {
+      if (!other->IsNumber()) return false;
+      uint32_t other_hash = static_cast<uint32_t>(other->Number());
+      return Hash() == other_hash;
+    }
     FixedArray* other_array = FixedArray::cast(other);
     SharedFunctionInfo* shared = SharedFunctionInfo::cast(other_array->get(0));
     if (shared != *shared_) return false;
     int strict_unchecked = Smi::cast(other_array->get(2))->value();
     DCHECK(strict_unchecked == SLOPPY || strict_unchecked == STRICT);
     StrictMode strict_mode = static_cast<StrictMode>(strict_unchecked);
     if (strict_mode != strict_mode_) return false;
     int scope_position = Smi::cast(other_array->get(3))->value();
     if (scope_position != scope_position_) return false;
     String* source = String::cast(other_array->get(1));
@@ skipping 19 matching lines @@
     return hash;
   }
 
   uint32_t Hash() OVERRIDE {
     return StringSharedHashHelper(*source_, *shared_, strict_mode_,
                                   scope_position_);
   }
 
   uint32_t HashForObject(Object* obj) OVERRIDE {
     DisallowHeapAllocation no_allocation;
+    if (obj->IsNumber()) {
+      return static_cast<uint32_t>(obj->Number());
+    }
     FixedArray* other_array = FixedArray::cast(obj);
     SharedFunctionInfo* shared = SharedFunctionInfo::cast(other_array->get(0));
     String* source = String::cast(other_array->get(1));
     int strict_unchecked = Smi::cast(other_array->get(2))->value();
     DCHECK(strict_unchecked == SLOPPY || strict_unchecked == STRICT);
     StrictMode strict_mode = static_cast<StrictMode>(strict_unchecked);
     int scope_position = Smi::cast(other_array->get(3))->value();
     return StringSharedHashHelper(
         source, shared, strict_mode, scope_position);
   }
@@ skipping 1138 matching lines @@
 
 
 Handle<Object> CompilationCacheTable::Lookup(Handle<String> src,
                                              Handle<Context> context) {
   Isolate* isolate = GetIsolate();
   Handle<SharedFunctionInfo> shared(context->closure()->shared());
   StringSharedKey key(src, shared, FLAG_use_strict ? STRICT : SLOPPY,
                       RelocInfo::kNoPosition);
   int entry = FindEntry(&key);
   if (entry == kNotFound) return isolate->factory()->undefined_value();
-  return Handle<Object>(get(EntryToIndex(entry) + 1), isolate);
+  int index = EntryToIndex(entry);
+  if (!get(index)->IsFixedArray()) return isolate->factory()->undefined_value();
+  return Handle<Object>(get(index + 1), isolate);
 }
 
 
 Handle<Object> CompilationCacheTable::LookupEval(
     Handle<String> src, Handle<SharedFunctionInfo> outer_info,
     StrictMode strict_mode, int scope_position) {
   Isolate* isolate = GetIsolate();
   // Cache key is the tuple (source, outer shared function info, scope position)
   // to unambiguously identify the context chain the cached eval code assumes.
   StringSharedKey key(src, outer_info, strict_mode, scope_position);
   int entry = FindEntry(&key);
   if (entry == kNotFound) return isolate->factory()->undefined_value();
+  int index = EntryToIndex(entry);
+  if (!get(index)->IsFixedArray()) return isolate->factory()->undefined_value();
   return Handle<Object>(get(EntryToIndex(entry) + 1), isolate);
 }
 
 
 Handle<Object> CompilationCacheTable::LookupRegExp(Handle<String> src,
                                                    JSRegExp::Flags flags) {
   Isolate* isolate = GetIsolate();
   DisallowHeapAllocation no_allocation;
   RegExpKey key(src, flags);
   int entry = FindEntry(&key);
   if (entry == kNotFound) return isolate->factory()->undefined_value();
   return Handle<Object>(get(EntryToIndex(entry) + 1), isolate);
 }
 
 
 Handle<CompilationCacheTable> CompilationCacheTable::Put(
     Handle<CompilationCacheTable> cache, Handle<String> src,
     Handle<Context> context, Handle<Object> value) {
   Isolate* isolate = cache->GetIsolate();
   Handle<SharedFunctionInfo> shared(context->closure()->shared());
   StringSharedKey key(src, shared, FLAG_use_strict ? STRICT : SLOPPY,
                       RelocInfo::kNoPosition);
+  int entry = cache->FindEntry(&key);
+  if (entry != kNotFound) {
+    Handle<Object> k = key.AsHandle(isolate);
+    cache->set(EntryToIndex(entry), *k);
+    cache->set(EntryToIndex(entry) + 1, *value);
+    return cache;
+  }
+
   cache = EnsureCapacity(cache, 1, &key);
-  Handle<Object> k = key.AsHandle(isolate);
-  int entry = cache->FindInsertionEntry(key.Hash());
+  entry = cache->FindInsertionEntry(key.Hash());
+  Handle<Object> k =
+      isolate->factory()->NewNumber(static_cast<double>(key.Hash()));
   cache->set(EntryToIndex(entry), *k);
-  cache->set(EntryToIndex(entry) + 1, *value);
+  cache->set(EntryToIndex(entry) + 1, Smi::FromInt(kHashGenerations));
   cache->ElementAdded();
   return cache;
 }
 
 
 Handle<CompilationCacheTable> CompilationCacheTable::PutEval(
     Handle<CompilationCacheTable> cache, Handle<String> src,
     Handle<SharedFunctionInfo> outer_info, Handle<SharedFunctionInfo> value,
     int scope_position) {
   Isolate* isolate = cache->GetIsolate();
   StringSharedKey key(src, outer_info, value->strict_mode(), scope_position);
+  int entry = cache->FindEntry(&key);
+  if (entry != kNotFound) {
+    Handle<Object> k = key.AsHandle(isolate);
+    cache->set(EntryToIndex(entry), *k);
+    cache->set(EntryToIndex(entry) + 1, *value);
+    return cache;
+  }
+
   cache = EnsureCapacity(cache, 1, &key);
-  Handle<Object> k = key.AsHandle(isolate);
-  int entry = cache->FindInsertionEntry(key.Hash());
+  entry = cache->FindInsertionEntry(key.Hash());
+  Handle<Object> k =
+      isolate->factory()->NewNumber(static_cast<double>(key.Hash()));
   cache->set(EntryToIndex(entry), *k);
-  cache->set(EntryToIndex(entry) + 1, *value);
+  cache->set(EntryToIndex(entry) + 1, Smi::FromInt(kHashGenerations));
   cache->ElementAdded();
   return cache;
 }
 
 
 Handle<CompilationCacheTable> CompilationCacheTable::PutRegExp(
       Handle<CompilationCacheTable> cache, Handle<String> src,
       JSRegExp::Flags flags, Handle<FixedArray> value) {
   RegExpKey key(src, flags);
   cache = EnsureCapacity(cache, 1, &key);
   int entry = cache->FindInsertionEntry(key.Hash());
   // We store the value in the key slot, and compare the search key
   // to the stored value with a custon IsMatch function during lookups.
   cache->set(EntryToIndex(entry), *value);
   cache->set(EntryToIndex(entry) + 1, *value);
   cache->ElementAdded();
   return cache;
 }
 
 
+void CompilationCacheTable::Age() {
+  DisallowHeapAllocation no_allocation;
+  Object* the_hole_value = GetHeap()->the_hole_value();
+  for (int entry = 0, size = Capacity(); entry < size; entry++) {
+    int entry_index = EntryToIndex(entry);
+    int value_index = entry_index + 1;
+
+    if (get(entry_index)->IsNumber()) {
+      Smi* count = Smi::cast(get(value_index));
+      count = Smi::FromInt(count->value() - 1);
+      if (count->value() == 0) {
+        NoWriteBarrierSet(this, entry_index, the_hole_value);
+        NoWriteBarrierSet(this, value_index, the_hole_value);
+        ElementRemoved();
+      } else {
+        NoWriteBarrierSet(this, value_index, count);
+      }
+    } else if (get(entry_index)->IsFixedArray()) {
+      SharedFunctionInfo* info = SharedFunctionInfo::cast(get(value_index));
+      if (info->code()->kind() != Code::FUNCTION || info->code()->IsOld()) {
+        NoWriteBarrierSet(this, entry_index, the_hole_value);
+        NoWriteBarrierSet(this, value_index, the_hole_value);
+        ElementRemoved();
+      }
+    }
+  }
+}
+
+
 void CompilationCacheTable::Remove(Object* value) {
   DisallowHeapAllocation no_allocation;
   Object* the_hole_value = GetHeap()->the_hole_value();
   for (int entry = 0, size = Capacity(); entry < size; entry++) {
     int entry_index = EntryToIndex(entry);
     int value_index = entry_index + 1;
     if (get(value_index) == value) {
       NoWriteBarrierSet(this, entry_index, the_hole_value);
       NoWriteBarrierSet(this, value_index, the_hole_value);
       ElementRemoved();
@@ skipping 1565 matching lines @@
   Handle<DependentCode> codes =
       DependentCode::Insert(handle(cell->dependent_code(), info->isolate()),
                             DependentCode::kPropertyCellChangedGroup,
                             info->object_wrapper());
   if (*codes != cell->dependent_code()) cell->set_dependent_code(*codes);
   info->dependencies(DependentCode::kPropertyCellChangedGroup)->Add(
       cell, info->zone());
 }
 
 } }  // namespace v8::internal