1 files changed, 133 insertions, 59 deletions

diff --git a/Source/JavaScriptCore/runtime/JSSymbolTableObject.h b/Source/JavaScriptCore/runtime/JSSymbolTableObject.h
index 6db2b88ab..368cedcb8 100644
--- a/Source/JavaScriptCore/runtime/JSSymbolTableObject.h
+++ b/Source/JavaScriptCore/runtime/JSSymbolTableObject.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2012, 2014, 2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -10,7 +10,7 @@
  * 2.  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 with the distribution. 
- * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
  *     its contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission. 
  *
@@ -32,40 +32,48 @@
 #include "JSScope.h"
 #include "PropertyDescriptor.h"
 #include "SymbolTable.h"
+#include "VariableWriteFireDetail.h"
 
 namespace JSC {
 
+class JSSymbolTableObject;
+
 class JSSymbolTableObject : public JSScope {
 public:
     typedef JSScope Base;
+    static const unsigned StructureFlags = Base::StructureFlags | IsEnvironmentRecord | OverridesGetPropertyNames;
     
-    SharedSymbolTable* symbolTable() const { return m_symbolTable.get(); }
-    
-    static NO_RETURN_DUE_TO_CRASH void putDirectVirtual(JSObject*, ExecState*, PropertyName, JSValue, unsigned attributes);
+    SymbolTable* symbolTable() const { return m_symbolTable.get(); }
     
     JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, ExecState*, PropertyName);
     JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
     
+    static ptrdiff_t offsetOfSymbolTable() { return OBJECT_OFFSETOF(JSSymbolTableObject, m_symbolTable); }
+    
 protected:
-    static const unsigned StructureFlags = IsEnvironmentRecord | OverridesVisitChildren | OverridesGetPropertyNames | Base::StructureFlags;
+    JSSymbolTableObject(VM& vm, Structure* structure, JSScope* scope)
+        : Base(vm, structure, scope)
+    {
+    }
     
-    JSSymbolTableObject(VM& vm, Structure* structure, JSScope* scope, SharedSymbolTable* symbolTable = 0)
+    JSSymbolTableObject(VM& vm, Structure* structure, JSScope* scope, SymbolTable* symbolTable)
         : Base(vm, structure, scope)
     {
-        if (symbolTable)
-            m_symbolTable.set(vm, this, symbolTable);
+        ASSERT(symbolTable);
+        setSymbolTable(vm, symbolTable);
     }
-
-    void finishCreation(VM& vm)
+    
+    void setSymbolTable(VM& vm, SymbolTable* symbolTable)
     {
-        Base::finishCreation(vm);
-        if (!m_symbolTable)
-            m_symbolTable.set(vm, this, SharedSymbolTable::create(vm));
+        ASSERT(!m_symbolTable);
+        symbolTable->singletonScope()->notifyWrite(vm, this, "Allocated a scope");
+        m_symbolTable.set(vm, this, symbolTable);
     }
-
+    
     static void visitChildren(JSCell*, SlotVisitor&);
-
-    WriteBarrier<SharedSymbolTable> m_symbolTable;
+    
+private:
+    WriteBarrier<SymbolTable> m_symbolTable;
 };
 
 template<typename SymbolTableObjectType>
@@ -73,12 +81,19 @@ inline bool symbolTableGet(
     SymbolTableObjectType* object, PropertyName propertyName, PropertySlot& slot)
 {
     SymbolTable& symbolTable = *object->symbolTable();
-    SymbolTable::iterator iter = symbolTable.find(propertyName.publicName());
-    if (iter == symbolTable.end())
+    ConcurrentJITLocker locker(symbolTable.m_lock);
+    SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
+    if (iter == symbolTable.end(locker))
         return false;
     SymbolTableEntry::Fast entry = iter->value;
     ASSERT(!entry.isNull());
-    slot.setValue(object->registerAt(entry.getIndex()).get());
+
+    ScopeOffset offset = entry.scopeOffset();
+    // Defend against the inspector asking for a var after it has been optimized out.
+    if (!object->isValidScopeOffset(offset))
+        return false;
+
+    slot.setValue(object, entry.getAttributes() | DontDelete, object->variableAt(offset).get());
     return true;
 }
 
@@ -87,13 +102,19 @@ inline bool symbolTableGet(
     SymbolTableObjectType* object, PropertyName propertyName, PropertyDescriptor& descriptor)
 {
     SymbolTable& symbolTable = *object->symbolTable();
-    SymbolTable::iterator iter = symbolTable.find(propertyName.publicName());
-    if (iter == symbolTable.end())
+    ConcurrentJITLocker locker(symbolTable.m_lock);
+    SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
+    if (iter == symbolTable.end(locker))
         return false;
     SymbolTableEntry::Fast entry = iter->value;
     ASSERT(!entry.isNull());
-    descriptor.setDescriptor(
-        object->registerAt(entry.getIndex()).get(), entry.getAttributes() | DontDelete);
+
+    ScopeOffset offset = entry.scopeOffset();
+    // Defend against the inspector asking for a var after it has been optimized out.
+    if (!object->isValidScopeOffset(offset))
+        return false;
+
+    descriptor.setDescriptor(object->variableAt(offset).get(), entry.getAttributes() | DontDelete);
     return true;
 }
 
@@ -103,58 +124,111 @@ inline bool symbolTableGet(
     bool& slotIsWriteable)
 {
     SymbolTable& symbolTable = *object->symbolTable();
-    SymbolTable::iterator iter = symbolTable.find(propertyName.publicName());
-    if (iter == symbolTable.end())
+    ConcurrentJITLocker locker(symbolTable.m_lock);
+    SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
+    if (iter == symbolTable.end(locker))
         return false;
     SymbolTableEntry::Fast entry = iter->value;
     ASSERT(!entry.isNull());
-    slot.setValue(object->registerAt(entry.getIndex()).get());
+
+    ScopeOffset offset = entry.scopeOffset();
+    // Defend against the inspector asking for a var after it has been optimized out.
+    if (!object->isValidScopeOffset(offset))
+        return false;
+
+    slot.setValue(object, entry.getAttributes() | DontDelete, object->variableAt(offset).get());
     slotIsWriteable = !entry.isReadOnly();
     return true;
 }
 
-template<typename SymbolTableObjectType>
+enum class SymbolTablePutMode {
+    WithAttributes,
+    WithoutAttributes
+};
+
+template<SymbolTablePutMode symbolTablePutMode, typename SymbolTableObjectType>
 inline bool symbolTablePut(
-    SymbolTableObjectType* object, ExecState* exec, PropertyName propertyName, JSValue value,
-    bool shouldThrow)
+    SymbolTableObjectType* object, ExecState* exec, PropertyName propertyName, JSValue value, unsigned attributes,
+    bool shouldThrowReadOnlyError, bool ignoreReadOnlyErrors, WatchpointSet*& set)
 {
-    VM& vm = exec->vm();
     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(object));
-    
-    SymbolTable& symbolTable = *object->symbolTable();
-    SymbolTable::iterator iter = symbolTable.find(propertyName.publicName());
-    if (iter == symbolTable.end())
-        return false;
-    bool wasFat;
-    SymbolTableEntry::Fast fastEntry = iter->value.getFast(wasFat);
-    ASSERT(!fastEntry.isNull());
-    if (fastEntry.isReadOnly()) {
-        if (shouldThrow)
-            throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
-        return true;
+
+    VM& vm = exec->vm();
+
+    WriteBarrierBase<Unknown>* reg;
+    {
+        SymbolTable& symbolTable = *object->symbolTable();
+        // FIXME: This is very suspicious. We shouldn't need a GC-safe lock here.
+        // https://bugs.webkit.org/show_bug.cgi?id=134601
+        GCSafeConcurrentJITLocker locker(symbolTable.m_lock, vm.heap);
+        SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
+        if (iter == symbolTable.end(locker))
+            return false;
+        bool wasFat;
+        SymbolTableEntry::Fast fastEntry = iter->value.getFast(wasFat);
+        ASSERT(!fastEntry.isNull());
+        if (fastEntry.isReadOnly() && !ignoreReadOnlyErrors) {
+            if (shouldThrowReadOnlyError)
+                throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
+            return true;
+        }
+
+        ScopeOffset offset = fastEntry.scopeOffset();
+
+        // Defend against the inspector asking for a var after it has been optimized out.
+        if (!object->isValidScopeOffset(offset))
+            return false;
+
+        set = iter->value.watchpointSet();
+        if (symbolTablePutMode == SymbolTablePutMode::WithAttributes)
+            iter->value.setAttributes(attributes);
+        reg = &object->variableAt(offset);
     }
-    if (UNLIKELY(wasFat))
-        iter->value.notifyWrite();
-    object->registerAt(fastEntry.getIndex()).set(vm, object, value);
+    // I'd prefer we not hold lock while executing barriers, since I prefer to reserve
+    // the right for barriers to be able to trigger GC. And I don't want to hold VM
+    // locks while GC'ing.
+    reg->set(vm, object, value);
     return true;
 }
 
 template<typename SymbolTableObjectType>
-inline bool symbolTablePutWithAttributes(
-    SymbolTableObjectType* object, VM& vm, PropertyName propertyName,
+inline bool symbolTablePutTouchWatchpointSet(
+    SymbolTableObjectType* object, ExecState* exec, PropertyName propertyName, JSValue value,
+    bool shouldThrowReadOnlyError, bool ignoreReadOnlyErrors)
+{
+    WatchpointSet* set = nullptr;
+    unsigned attributes = 0;
+    bool result = symbolTablePut<SymbolTablePutMode::WithoutAttributes>(object, exec, propertyName, value, attributes, shouldThrowReadOnlyError, ignoreReadOnlyErrors, set);
+    if (set)
+        VariableWriteFireDetail::touch(set, object, propertyName);
+    return result;
+}
+
+template<typename SymbolTableObjectType>
+inline bool symbolTablePutInvalidateWatchpointSet(
+    SymbolTableObjectType* object, ExecState* exec, PropertyName propertyName, JSValue value,
+    bool shouldThrowReadOnlyError, bool ignoreReadOnlyErrors)
+{
+    WatchpointSet* set = nullptr;
+    unsigned attributes = 0;
+    bool result = symbolTablePut<SymbolTablePutMode::WithoutAttributes>(object, exec, propertyName, value, attributes, shouldThrowReadOnlyError, ignoreReadOnlyErrors, set);
+    if (set)
+        set->invalidate(VariableWriteFireDetail(object, propertyName)); // Don't mess around - if we had found this statically, we would have invalidated it.
+    return result;
+}
+
+template<typename SymbolTableObjectType>
+inline bool symbolTablePutWithAttributesTouchWatchpointSet(
+    SymbolTableObjectType* object, ExecState* exec, PropertyName propertyName,
     JSValue value, unsigned attributes)
 {
-    ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(object));
-    
-    SymbolTable::iterator iter = object->symbolTable()->find(propertyName.publicName());
-    if (iter == object->symbolTable()->end())
-        return false;
-    SymbolTableEntry& entry = iter->value;
-    ASSERT(!entry.isNull());
-    entry.notifyWrite();
-    entry.setAttributes(attributes);
-    object->registerAt(entry.getIndex()).set(vm, object, value);
-    return true;
+    WatchpointSet* set = nullptr;
+    bool shouldThrowReadOnlyError = false;
+    bool ignoreReadOnlyErrors = true;
+    bool result = symbolTablePut<SymbolTablePutMode::WithAttributes>(object, exec, propertyName, value, attributes, shouldThrowReadOnlyError, ignoreReadOnlyErrors, set);
+    if (set)
+        VariableWriteFireDetail::touch(set, object, propertyName);
+    return result;
 }
 
 } // namespace JSC