Support for the with statement

Add the with object (list) to the environment, and check properties
there if it's available.
Generate IR statements implementing with() support.
Add two new builtin methods to enter and leave a with scope.
Implement support for the builtin's in masm.
Make sure exception handling works across with scopes.

Change-Id: I8257a16cfccc91a1acedfd740ade711b016b33fd
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

diff --git a/qmljs_engine.h b/qmljs_engine.h
index 5460412..8d56627 100644 (file)
--- a/qmljs_engine.h
+++ b/qmljs_engine.h
@@ -131,6 +131,7 @@ struct ExecutionEngine
 
     struct ExceptionHandler {
         ExecutionContext *context;
+        DeclarativeEnvironment::With *with;
         const uchar *code; // Interpreter state
         int targetTempIndex; // Interpreter state
         jmp_buf stackFrame;

diff --git a/qmljs_environment.cpp b/qmljs_environment.cpp
index 121670c..5504763 100644 (file)
--- a/qmljs_environment.cpp
+++ b/qmljs_environment.cpp
@@ -52,11 +52,12 @@ DeclarativeEnvironment::DeclarativeEnvironment(ExecutionEngine *e)
     arguments = 0;
     argumentCount = 0;
     locals = 0;
-    activation = 0;
     formals = 0;
     formalCount = 0;
     vars = 0;
     varCount = 0;
+    activation = 0;
+    withObject = 0;
 }
 
 DeclarativeEnvironment::DeclarativeEnvironment(FunctionObject *f, Value *args, uint argc)
@@ -64,11 +65,6 @@ DeclarativeEnvironment::DeclarativeEnvironment(FunctionObject *f, Value *args, u
     outer = f->scope;
     engine = outer->engine;
 
-    if (f->needsActivation)
-        activation = engine->newActivationObject(this);
-    else
-        activation = 0;
-
     formals = f->formalParameterList;
     formalCount = f->formalParameterCount;
     arguments = args;
@@ -85,6 +81,13 @@ DeclarativeEnvironment::DeclarativeEnvironment(FunctionObject *f, Value *args, u
     locals = varCount ? new Value[varCount] : 0;
     if (varCount)
         std::fill(locals, locals + varCount, Value::undefinedValue());
+
+    if (f->needsActivation)
+        activation = engine->newActivationObject(this);
+    else
+        activation = 0;
+
+    withObject = 0;
 }
 
 bool DeclarativeEnvironment::hasBinding(String *name) const
@@ -97,7 +100,9 @@ bool DeclarativeEnvironment::hasBinding(String *name) const
         if (__qmljs_string_equal(formals[i], name))
             return true;
     }
-    return deletableLocals.contains(name->toQString());
+    if (!deletableLocals)
+        return false;
+    return deletableLocals->contains(name->toQString());
 }
 
 void DeclarativeEnvironment::createMutableBinding(String *name, bool deletable)
@@ -106,7 +111,9 @@ void DeclarativeEnvironment::createMutableBinding(String *name, bool deletable)
     assert(deletable);
     assert(!hasBinding(name));
 
-    deletableLocals.insert(name->toQString(), Value::undefinedValue());
+    if (!deletableLocals)
+        deletableLocals = new QHash<QString, Value>();
+    deletableLocals->insert(name->toQString(), Value::undefinedValue());
 }
 
 void DeclarativeEnvironment::setMutableBinding(String *name, Value value, bool strict)
@@ -126,8 +133,9 @@ void DeclarativeEnvironment::setMutableBinding(String *name, Value value, bool s
             return;
         }
     }
-    QHash<QString, Value>::iterator it = deletableLocals.find(name->toQString());
-    if (it != deletableLocals.end()) {
+    assert(deletableLocals);
+    QHash<QString, Value>::iterator it = deletableLocals->find(name->toQString());
+    if (it != deletableLocals->end()) {
         *it = value;
         return;
     }
@@ -146,8 +154,9 @@ Value DeclarativeEnvironment::getBindingValue(String *name, bool strict) const
         if (__qmljs_string_equal(formals[i], name))
             return arguments[i];
     }
-    QHash<QString, Value>::const_iterator it = deletableLocals.find(name->toQString());
-    if (it != deletableLocals.end())
+    assert(deletableLocals);
+    QHash<QString, Value>::const_iterator it = deletableLocals->find(name->toQString());
+    if (it != deletableLocals->end())
         return *it;
 
     assert(false);
@@ -155,14 +164,33 @@ Value DeclarativeEnvironment::getBindingValue(String *name, bool strict) const
 
 bool DeclarativeEnvironment::deleteBinding(String *name)
 {
-    QHash<QString, Value>::iterator it = deletableLocals.find(name->toQString());
-    if (it != deletableLocals.end()) {
-        deletableLocals.erase(it);
-        return true;
+    if (deletableLocals) {
+        QHash<QString, Value>::iterator it = deletableLocals->find(name->toQString());
+        if (it != deletableLocals->end()) {
+            deletableLocals->erase(it);
+            return true;
+        }
     }
     return !hasBinding(name);
 }
 
+void DeclarativeEnvironment::pushWithObject(Object *with)
+{
+    With *w = new With;
+    w->next = withObject;
+    w->object = with;
+    withObject = w;
+}
+
+void DeclarativeEnvironment::popWithObject()
+{
+    assert(withObject);
+
+    With *w = withObject;
+    withObject = w->next;
+    delete w;
+}
+
 
 void ExecutionContext::init(ExecutionEngine *eng)
 {
@@ -177,6 +205,14 @@ void ExecutionContext::init(ExecutionEngine *eng)
 PropertyDescriptor *ExecutionContext::lookupPropertyDescriptor(String *name, PropertyDescriptor *tmp)
 {
     for (DeclarativeEnvironment *ctx = lexicalEnvironment; ctx; ctx = ctx->outer) {
+        if (ctx->withObject) {
+            DeclarativeEnvironment::With *w = ctx->withObject;
+            while (w) {
+                if (PropertyDescriptor *pd = w->object->__getPropertyDescriptor__(this, name, tmp))
+                    return pd;
+                w = w->next;
+            }
+        }
         if (ctx->activation) {
             if (PropertyDescriptor *pd = ctx->activation->__getPropertyDescriptor__(this, name, tmp))
                 return pd;

diff --git a/qmljs_environment.h b/qmljs_environment.h
index b16c0f9..7a3a012 100644 (file)
--- a/qmljs_environment.h
+++ b/qmljs_environment.h
@@ -59,7 +59,6 @@ struct DeclarativeEnvironment
     ExecutionEngine *engine;
     DeclarativeEnvironment *outer;
 
-    Object *activation;
     Value *arguments;
     unsigned int argumentCount;
     Value *locals;
@@ -68,18 +67,29 @@ struct DeclarativeEnvironment
     String **vars;
     unsigned int varCount;
 
+    Object *activation;
+    struct With {
+        Object *object;
+        With *next;
+    } *withObject;
+
     // these get used for createMutableBinding(..., true).
     // the only place this is being used is eval(...)
-    QHash<QString, Value> deletableLocals;
+    QHash<QString, Value> *deletableLocals;
 
     DeclarativeEnvironment(ExecutionEngine *e);
     DeclarativeEnvironment(FunctionObject *f, Value *args, uint argc);
+    ~DeclarativeEnvironment() { delete deletableLocals; }
 
     bool hasBinding(String *name) const;
     void createMutableBinding(String *name, bool deletable);
     void setMutableBinding(String *name, Value value, bool strict);
     Value getBindingValue(String *name, bool strict) const;
     bool deleteBinding(String *name);
+
+    // ### needs a bit of work in exception handlers
+    void pushWithObject(Object *with);
+    void popWithObject();
 };
 
 struct ExecutionContext

diff --git a/qmljs_runtime.cpp b/qmljs_runtime.cpp
index 4053e42..eabceef 100644 (file)
--- a/qmljs_runtime.cpp
+++ b/qmljs_runtime.cpp
@@ -819,6 +819,12 @@ void __qmljs_throw(Value value, ExecutionContext *context)
         context->leaveCallContext();
         context = context->parent;
     }
+    DeclarativeEnvironment *env = context->lexicalEnvironment;
+    while (env->withObject != handler.with) {
+        DeclarativeEnvironment::With *w = env->withObject;
+        env->withObject = w->next;
+        delete w;
+    }
 
     context->engine->exception = value;
 
@@ -831,6 +837,7 @@ void *__qmljs_create_exception_handler(ExecutionContext *context)
     context->engine->unwindStack.append(ExecutionEngine::ExceptionHandler());
     ExecutionEngine::ExceptionHandler &handler = context->engine->unwindStack.last();
     handler.context = context;
+    handler.with = context->lexicalEnvironment->withObject;
     return handler.stackFrame;
 }
 
@@ -856,6 +863,17 @@ void __qmljs_builtin_throw(Value val, ExecutionContext *context)
     __qmljs_throw(val, context);
 }
 
+void __qmljs_builtin_push_with(Value o, ExecutionContext *ctx)
+{
+    Object *obj = __qmljs_to_object(o, ctx).asObject();
+    ctx->lexicalEnvironment->pushWithObject(obj);
+}
+
+void __qmljs_builtin_pop_with(ExecutionContext *ctx)
+{
+    ctx->lexicalEnvironment->popWithObject();
+}
+
 
 } // extern "C"
 

diff --git a/qmljs_runtime.h b/qmljs_runtime.h
index 4a1e348..ff8395a 100644 (file)
--- a/qmljs_runtime.h
+++ b/qmljs_runtime.h
@@ -101,6 +101,8 @@ Value __qmljs_construct_value(ExecutionContext *context, Value func, Value *args
 
 Value __qmljs_builtin_typeof(Value val, ExecutionContext *context);
 void __qmljs_builtin_throw(Value val, ExecutionContext *context);
+void __qmljs_builtin_push_with(Value o, ExecutionContext *ctx);
+void __qmljs_builtin_pop_with(ExecutionContext *ctx);
 
 // constructors
 Value __qmljs_init_closure(IR::Function *clos, ExecutionContext *ctx);

diff --git a/qv4codegen.cpp b/qv4codegen.cpp
index a8e3c0b..33bb064 100644 (file)
--- a/qv4codegen.cpp
+++ b/qv4codegen.cpp
@@ -665,7 +665,7 @@ void Codegen::variableDeclaration(VariableDeclaration *ast)
     if (! initializer)
         initializer = _block->CONST(IR::UndefinedType, 0);
 
-    if (! _env->parent) {
+    if (! _env->parent || _function->insideWith) {
         // it's global code.
         move(_block->NAME(ast->name.toString(), ast->identifierToken.startLine, ast->identifierToken.startColumn), initializer);
     } else {
@@ -1113,7 +1113,7 @@ IR::Expr *Codegen::identifier(const QString &name, int line, int col)
 {
     int index = _env->findMember(name);
 
-    if (! _function->hasDirectEval && _env->parent) {
+    if (! _function->hasDirectEval && !_function->insideWith && _env->parent) {
         if (index != -1) {
             return _block->TEMP(index);
         }
@@ -2137,9 +2137,26 @@ bool Codegen::visit(WhileStatement *ast)
     return false;
 }
 
-bool Codegen::visit(WithStatement *)
+bool Codegen::visit(WithStatement *ast)
 {
-    assert(!"with not implemented");
+    IR::BasicBlock *withBlock = _function->newBasicBlock();
+
+    _block->JUMP(withBlock);
+    _block = withBlock;
+    int withObject = _block->newTemp();
+    _block->MOVE(_block->TEMP(withObject), *expression(ast->expression));
+    IR::ExprList *args = _function->New<IR::ExprList>();
+    args->init(_block->TEMP(withObject));
+    _block->EXP(_block->CALL(_block->NAME(IR::Name::builtin_push_with, 0, 0), args));
+    ++_function->insideWith;
+    statement(ast->statement);
+    --_function->insideWith;
+    _block->EXP(_block->CALL(_block->NAME(IR::Name::builtin_pop_with, 0, 0), 0));
+
+    IR::BasicBlock *next = _function->newBasicBlock();
+    _block->JUMP(next);
+    _block = next;
+
     return false;
 }
 

diff --git a/qv4ir.cpp b/qv4ir.cpp
index 6d23129..57f6de9 100644 (file)
--- a/qv4ir.cpp
+++ b/qv4ir.cpp
@@ -234,6 +234,10 @@ static const char *builtin_to_string(Name::Builtin b)
         return "builtin_foreach_iterator_object";
     case IR::Name::builtin_foreach_next_property_name:
         return "builtin_foreach_next_property_name";
+    case IR::Name::builtin_push_with:
+        return "builtin_push_with";
+    case IR::Name::builtin_pop_with:
+        return "builtin_pop_with";
     }
     return "builtin_(###FIXME)";
 };

diff --git a/qv4ir_p.h b/qv4ir_p.h
index 502275d..b0be0f9 100644 (file)
--- a/qv4ir_p.h
+++ b/qv4ir_p.h
@@ -276,7 +276,9 @@ struct Name: Expr {
         builtin_delete_exception_handler,
         builtin_get_exception,
         builtin_foreach_iterator_object,
-        builtin_foreach_next_property_name
+        builtin_foreach_next_property_name,
+        builtin_push_with,
+        builtin_pop_with
     };
 
     const QString *id;
@@ -601,6 +603,7 @@ struct Function {
 
     bool hasDirectEval: 1;
     bool hasNestedFunctions: 1;
+    int insideWith;
 
     template <typename _Tp> _Tp *New() { return new (pool->allocate(sizeof(_Tp))) _Tp(); }
 
@@ -613,6 +616,7 @@ struct Function {
         , codeData(0)
         , hasDirectEval(false)
         , hasNestedFunctions(false)
+        , insideWith(0)
     { this->name = newString(name); }
 
     ~Function();

diff --git a/qv4isel_masm.cpp b/qv4isel_masm.cpp
index 3bd4049..270209a 100644 (file)
--- a/qv4isel_masm.cpp
+++ b/qv4isel_masm.cpp
@@ -264,6 +264,15 @@ void InstructionSelection::callActivationProperty(IR::Call *call, IR::Temp *resu
         generateFunctionCall(result, __qmljs_foreach_next_property_name, arg);
     }
         break;
+    case IR::Name::builtin_push_with: {
+        IR::Temp *arg = call->args->expr->asTemp();
+        assert(arg != 0);
+        generateFunctionCall(Void, __qmljs_builtin_push_with, arg, ContextRegister);
+    }
+        break;
+    case IR::Name::builtin_pop_with:
+        generateFunctionCall(Void, __qmljs_builtin_pop_with, ContextRegister);
+        break;
     }
 }
 

diff --git a/tests/with.js b/tests/with.js
new file mode 100644 (file)
index 0000000..91ab5a0
--- /dev/null
+++ b/tests/with.js
@@ -0,0 +1,43 @@
+var o = { "x": 1 }
+var x = 0;
+with(o) {
+    with( { "x": 2 } ) {
+        print(x)
+    }
+    print(x)
+}
+print(x)
+
+
+function foo() {
+    var x = 0;
+    with(o) {
+        with( { "x": 2 } ) {
+            print(x)
+        }
+        print(x)
+    }
+    print(x)
+}
+
+print("\n")
+foo();
+
+
+function bar() {
+    var x = 0;
+    try {
+        with(o) {
+            with( { "x": 2 } ) {
+                print(x)
+                throw 0;
+            }
+            print(x)
+        }
+    }
+    catch(e) {}
+    print(x)
+}
+
+print("\n")
+bar();