webkitgtk-2.12.3webkitgtk-2.12.3

1 files changed, 186 insertions, 31 deletions

diff --git a/Source/JavaScriptCore/runtime/JSScope.cpp b/Source/JavaScriptCore/runtime/JSScope.cpp
index 3440bc610..b13f3ff4a 100644
--- a/Source/JavaScriptCore/runtime/JSScope.cpp
+++ b/Source/JavaScriptCore/runtime/JSScope.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012, 2013 Apple Inc. All Rights Reserved.
+ * Copyright (C) 2012-2015 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -26,11 +26,12 @@
 #include "config.h"
 #include "JSScope.h"
 
-#include "JSActivation.h"
 #include "JSGlobalObject.h"
-#include "JSNameScope.h"
+#include "JSLexicalEnvironment.h"
+#include "JSModuleEnvironment.h"
+#include "JSModuleRecord.h"
 #include "JSWithScope.h"
-#include "Operations.h"
+#include "JSCInlines.h"
 
 namespace JSC {
 
@@ -40,40 +41,77 @@ void JSScope::visitChildren(JSCell* cell, SlotVisitor& visitor)
 {
     JSScope* thisObject = jsCast<JSScope*>(cell);
     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
-    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
-    ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
-
     Base::visitChildren(thisObject, visitor);
     visitor.append(&thisObject->m_next);
 }
 
 // Returns true if we found enough information to terminate optimization.
-static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, size_t depth, bool& needsVarInjectionChecks, ResolveOp& op)
+static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, size_t depth, bool& needsVarInjectionChecks, ResolveOp& op, InitializationMode initializationMode)
 {
-    if (JSActivation* activation = jsDynamicCast<JSActivation*>(scope)) {
+    if (JSLexicalEnvironment* lexicalEnvironment = jsDynamicCast<JSLexicalEnvironment*>(scope)) {
         if (ident == exec->propertyNames().arguments) {
-            // We know the property will be at this activation scope, but we don't know how to cache it.
+            // We know the property will be at this lexical environment scope, but we don't know how to cache it.
             op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
             return true;
         }
 
-        SymbolTableEntry entry = activation->symbolTable()->get(ident.impl());
+        SymbolTableEntry entry = lexicalEnvironment->symbolTable()->get(ident.impl());
         if (entry.isReadOnly() && getOrPut == Put) {
-            // We know the property will be at this activation scope, but we don't know how to cache it.
+            // We know the property will be at this lexical environment scope, but we don't know how to cache it.
             op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
             return true;
         }
 
         if (!entry.isNull()) {
-            op = ResolveOp(makeType(ClosureVar, needsVarInjectionChecks), depth, 0, activation, entry.watchpointSet(), entry.getIndex());
+            op = ResolveOp(makeType(ClosureVar, needsVarInjectionChecks), depth, 0, lexicalEnvironment, entry.watchpointSet(), entry.scopeOffset().offset());
             return true;
         }
 
-        if (activation->symbolTable()->usesNonStrictEval())
+        if (JSModuleEnvironment* moduleEnvironment = jsDynamicCast<JSModuleEnvironment*>(scope)) {
+            JSModuleRecord* moduleRecord = moduleEnvironment->moduleRecord();
+            JSModuleRecord::Resolution resolution = moduleRecord->resolveImport(exec, ident);
+            if (resolution.type == JSModuleRecord::Resolution::Type::Resolved) {
+                JSModuleRecord* importedRecord = resolution.moduleRecord;
+                JSModuleEnvironment* importedEnvironment = importedRecord->moduleEnvironment();
+                SymbolTableEntry entry = importedEnvironment->symbolTable()->get(resolution.localName.impl());
+                ASSERT(!entry.isNull());
+                op = ResolveOp(makeType(ModuleVar, needsVarInjectionChecks), depth, 0, importedEnvironment, entry.watchpointSet(), entry.scopeOffset().offset(), resolution.localName.impl());
+                return true;
+            }
+        }
+
+        if (lexicalEnvironment->symbolTable()->usesNonStrictEval())
             needsVarInjectionChecks = true;
         return false;
     }
 
+    if (JSGlobalLexicalEnvironment* globalLexicalEnvironment = jsDynamicCast<JSGlobalLexicalEnvironment*>(scope)) {
+        SymbolTableEntry entry = globalLexicalEnvironment->symbolTable()->get(ident.impl());
+        if (!entry.isNull()) {
+            if (getOrPut == Put && entry.isReadOnly() && initializationMode != Initialization) {
+                // We know the property will be at global lexical environment, but we don't know how to cache it.
+                op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
+                return true;
+            }
+
+            // We can try to force const Initialization to always go down the fast path. It is provably impossible to construct
+            // a program that needs a var injection check here. You can convince yourself of this as follows:
+            // Any other let/const/class would be a duplicate of this in the global scope, so we would never get here in that situation.
+            // Also, if we had an eval in the global scope that defined a const, it would also be a duplicate of this const, and so it would
+            // also throw an error. Therefore, we're *the only* thing that can assign to this "const" slot for the first (and only) time. Also, 
+            // we will never have a Dynamic ResolveType here because if we were inside a "with" statement, that would mean the "const" definition 
+            // isn't a global, it would be a local to the "with" block. 
+            // We still need to make the slow path correct for when we need to fire a watchpoint.
+            ResolveType resolveType = initializationMode == Initialization ? GlobalLexicalVar : makeType(GlobalLexicalVar, needsVarInjectionChecks);
+            op = ResolveOp(
+                resolveType, depth, 0, 0, entry.watchpointSet(),
+                reinterpret_cast<uintptr_t>(globalLexicalEnvironment->variableAt(entry.scopeOffset()).slot()));
+            return true;
+        }
+
+        return false;
+    }
+
     if (JSGlobalObject* globalObject = jsDynamicCast<JSGlobalObject*>(scope)) {
         SymbolTableEntry entry = globalObject->symbolTable()->get(ident.impl());
         if (!entry.isNull()) {
@@ -85,22 +123,39 @@ static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identif
 
             op = ResolveOp(
                 makeType(GlobalVar, needsVarInjectionChecks), depth, 0, 0, entry.watchpointSet(),
-                reinterpret_cast<uintptr_t>(globalObject->registerAt(entry.getIndex()).slot()));
+                reinterpret_cast<uintptr_t>(globalObject->variableAt(entry.scopeOffset()).slot()));
             return true;
         }
 
-        PropertySlot slot(globalObject);
-        if (!globalObject->getOwnPropertySlot(globalObject, exec, ident, slot)
-            || !slot.isCacheableValue()
+        PropertySlot slot(globalObject, PropertySlot::InternalMethodType::VMInquiry);
+        bool hasOwnProperty = globalObject->getOwnPropertySlot(globalObject, exec, ident, slot);
+        if (!hasOwnProperty) {
+            op = ResolveOp(makeType(UnresolvedProperty, needsVarInjectionChecks), 0, 0, 0, 0, 0);
+            return true;
+        }
+
+        if (!slot.isCacheableValue()
             || !globalObject->structure()->propertyAccessesAreCacheable()
             || (globalObject->structure()->hasReadOnlyOrGetterSetterPropertiesExcludingProto() && getOrPut == Put)) {
             // We know the property will be at global scope, but we don't know how to cache it.
             ASSERT(!scope->next());
-            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, 0, 0, 0, 0);
+            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), 0, 0, 0, 0, 0);
             return true;
         }
 
-        op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, globalObject->structure(), 0, 0, slot.cachedOffset());
+        
+        WatchpointState state = globalObject->structure()->ensurePropertyReplacementWatchpointSet(exec->vm(), slot.cachedOffset())->state();
+        if (state == IsWatched && getOrPut == Put) {
+            // The field exists, but because the replacement watchpoint is still intact. This is
+            // kind of dangerous. We have two options:
+            // 1) Invalidate the watchpoint set. That would work, but it's possible that this code
+            //    path never executes - in which case this would be unwise.
+            // 2) Have the invalidation happen at run-time. All we have to do is leave the code
+            //    uncached. The only downside is slightly more work when this does execute.
+            // We go with option (2) here because it seems less evil.
+            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, 0, 0, 0, 0);
+        } else
+            op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, globalObject->structure(), 0, 0, slot.cachedOffset());
         return true;
     }
 
@@ -111,18 +166,28 @@ static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identif
 JSObject* JSScope::objectAtScope(JSScope* scope)
 {
     JSObject* object = scope;
-    if (object->structure()->typeInfo().type() == WithScopeType)
+    if (object->type() == WithScopeType)
         return jsCast<JSWithScope*>(object)->object();
 
     return object;
 }
 
-int JSScope::depth()
+// When an exception occurs, the result of isUnscopable becomes false.
+static inline bool isUnscopable(ExecState* exec, JSScope* scope, JSObject* object, const Identifier& ident)
 {
-    int depth = 0;
-    for (JSScope* scope = this; scope; scope = scope->next())
-        ++depth;
-    return depth;
+    if (scope->type() != WithScopeType)
+        return false;
+
+    JSValue unscopables = object->get(exec, exec->propertyNames().unscopablesSymbol);
+    if (exec->hadException())
+        return false;
+    if (!unscopables.isObject())
+        return false;
+    JSValue blocked = jsCast<JSObject*>(unscopables)->get(exec, ident);
+    if (exec->hadException())
+        return false;
+
+    return blocked.toBoolean(exec);
 }
 
 JSValue JSScope::resolve(ExecState* exec, JSScope* scope, const Identifier& ident)
@@ -130,26 +195,30 @@ JSValue JSScope::resolve(ExecState* exec, JSScope* scope, const Identifier& iden
     ScopeChainIterator end = scope->end();
     ScopeChainIterator it = scope->begin();
     while (1) {
+        JSScope* scope = it.scope();
         JSObject* object = it.get();
 
         if (++it == end) // Global scope.
             return object;
 
-        if (object->hasProperty(exec, ident))
-            return object;
+        if (object->hasProperty(exec, ident)) {
+            if (!isUnscopable(exec, scope, object, ident))
+                return object;
+            ASSERT_WITH_MESSAGE(!exec->hadException(), "When an exception occurs, the result of isUnscopable becomes false");
+        }
     }
 }
 
-ResolveOp JSScope::abstractResolve(ExecState* exec, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, ResolveType unlinkedType)
+ResolveOp JSScope::abstractResolve(ExecState* exec, size_t depthOffset, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, ResolveType unlinkedType, InitializationMode initializationMode)
 {
     ResolveOp op(Dynamic, 0, 0, 0, 0, 0);
     if (unlinkedType == Dynamic)
         return op;
 
-    size_t depth = 0;
     bool needsVarInjectionChecks = JSC::needsVarInjectionChecks(unlinkedType);
+    size_t depth = depthOffset;
     for (; scope; scope = scope->next()) {
-        if (abstractAccess(exec, scope, ident, getOrPut, depth, needsVarInjectionChecks, op))
+        if (abstractAccess(exec, scope, ident, getOrPut, depth, needsVarInjectionChecks, op, initializationMode))
             break;
         ++depth;
     }
@@ -157,4 +226,90 @@ ResolveOp JSScope::abstractResolve(ExecState* exec, JSScope* scope, const Identi
     return op;
 }
 
+void JSScope::collectVariablesUnderTDZ(JSScope* scope, VariableEnvironment& result)
+{
+    for (; scope; scope = scope->next()) {
+        if (!scope->isLexicalScope() && !scope->isGlobalLexicalEnvironment())
+            continue;
+
+        if (scope->isModuleScope()) {
+            JSModuleRecord* moduleRecord = jsCast<JSModuleEnvironment*>(scope)->moduleRecord();
+            for (const auto& pair : moduleRecord->importEntries())
+                result.add(pair.key);
+        }
+
+        SymbolTable* symbolTable = jsCast<JSSymbolTableObject*>(scope)->symbolTable();
+        ASSERT(symbolTable->scopeType() == SymbolTable::ScopeType::LexicalScope || symbolTable->scopeType() == SymbolTable::ScopeType::GlobalLexicalScope);
+        ConcurrentJITLocker locker(symbolTable->m_lock);
+        for (auto end = symbolTable->end(locker), iter = symbolTable->begin(locker); iter != end; ++iter)
+            result.add(iter->key);
+    }
+}
+
+template <typename EnvironmentType, SymbolTable::ScopeType scopeType>
+inline static bool isScopeType(JSScope* scope)
+{
+    EnvironmentType* environment = jsDynamicCast<EnvironmentType*>(scope);
+    if (!environment)
+        return false;
+
+    return environment->symbolTable()->scopeType() == scopeType;
+}
+
+bool JSScope::isVarScope()
+{
+    return isScopeType<JSLexicalEnvironment, SymbolTable::ScopeType::VarScope>(this);
+}
+
+bool JSScope::isLexicalScope()
+{
+    return isScopeType<JSLexicalEnvironment, SymbolTable::ScopeType::LexicalScope>(this);
+}
+
+bool JSScope::isModuleScope()
+{
+    return isScopeType<JSModuleEnvironment, SymbolTable::ScopeType::LexicalScope>(this);
+}
+
+bool JSScope::isCatchScope()
+{
+    return isScopeType<JSLexicalEnvironment, SymbolTable::ScopeType::CatchScope>(this);
+}
+
+bool JSScope::isFunctionNameScopeObject()
+{
+    return isScopeType<JSLexicalEnvironment, SymbolTable::ScopeType::FunctionNameScope>(this);
+}
+
+bool JSScope::isGlobalLexicalEnvironment()
+{
+    return isScopeType<JSGlobalLexicalEnvironment, SymbolTable::ScopeType::GlobalLexicalScope>(this);
+}
+
+bool JSScope::isNestedLexicalScope()
+{
+    if (JSLexicalEnvironment* environment = jsDynamicCast<JSLexicalEnvironment*>(this))
+        return environment->symbolTable()->isNestedLexicalScope();
+    return false;
+}
+
+JSScope* JSScope::constantScopeForCodeBlock(ResolveType type, CodeBlock* codeBlock)
+{
+    switch (type) {
+    case GlobalProperty:
+    case GlobalVar:
+    case GlobalPropertyWithVarInjectionChecks:
+    case GlobalVarWithVarInjectionChecks:
+        return codeBlock->globalObject();
+    case GlobalLexicalVarWithVarInjectionChecks:
+    case GlobalLexicalVar:
+        return codeBlock->globalObject()->globalLexicalEnvironment();
+    default:
+        return nullptr;
+    }
+
+    RELEASE_ASSERT_NOT_REACHED();
+    return nullptr;
+}
+
 } // namespace JSC