Clean up JSCallData setup

We either have pre-populated arguments and thisObject, then we can just
use them and keep them const. Or, we want to allocate and populate the
arguments and the thisObject. Then, do allocate them in a separate
object, and transform that into JSCallData afterwards if necessary.

Furthermore, avoid alloc(0) as that just returns the current stack top.
Writing to it will clobber other data. Rather, just use nullptr and
crash if it's written to.

Also, remove the useless operator-> from JSCallData. That one just
confuses the reader.

Change-Id: I8310911fcfe005b05a07b78fcb3791d991a0c2ce
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 45 insertions, 34 deletions

diff --git a/src/qml/jsruntime/qv4proxy.cpp b/src/qml/jsruntime/qv4proxy.cpp
index bc46f0ce58..b223e73f0f 100644
--- a/src/qml/jsruntime/qv4proxy.cpp
+++ b/src/qml/jsruntime/qv4proxy.cpp
@@ -90,10 +90,11 @@ ReturnedValue ProxyObject::virtualGet(const Managed *m, PropertyKey id, const Va
     if (hasProperty)
         *hasProperty = true;
 
-    JSCallData cdata(handler, scope.alloc(3), 3);
-    cdata.args[0] = target;
-    cdata.args[1] = id.toStringOrSymbol(scope.engine);
-    cdata.args[2] = *receiver;
+    Value *args = scope.alloc(3);
+    args[0] = target;
+    args[1] = id.toStringOrSymbol(scope.engine);
+    args[2] = *receiver;
+    JSCallData cdata(handler, args, 3);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
@@ -131,11 +132,12 @@ bool ProxyObject::virtualPut(Managed *m, PropertyKey id, const Value &value, Val
     if (!trap->isFunctionObject())
         return scope.engine->throwTypeError();
 
-    JSCallData cdata(handler, scope.alloc(4), 4);
-    cdata.args[0] = target;
-    cdata.args[1] = id.toStringOrSymbol(scope.engine);
-    cdata.args[2] = value;
-    cdata.args[3] = *receiver;
+    Value *args = scope.alloc(4);
+    args[0] = target;
+    args[1] = id.toStringOrSymbol(scope.engine);
+    args[2] = value;
+    args[3] = *receiver;
+    JSCallData cdata(handler, args, 4);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException || !trapResult->toBoolean())
@@ -172,10 +174,11 @@ bool ProxyObject::virtualDeleteProperty(Managed *m, PropertyKey id)
     if (!trap->isFunctionObject())
         return scope.engine->throwTypeError();
 
-    JSCallData cdata(handler, scope.alloc(3), 3);
-    cdata.args[0] = target;
-    cdata.args[1] = id.toStringOrSymbol(scope.engine);
-    cdata.args[2] = o->d(); // ### fix receiver handling
+    Value *args = scope.alloc(3);
+    args[0] = target;
+    args[1] = id.toStringOrSymbol(scope.engine);
+    args[2] = o->d(); // ### fix receiver handling
+    JSCallData cdata(handler, args, 3);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException || !trapResult->toBoolean())
@@ -208,9 +211,10 @@ bool ProxyObject::virtualHasProperty(const Managed *m, PropertyKey id)
     if (!trap->isFunctionObject())
         return scope.engine->throwTypeError();
 
-    JSCallData cdata(handler, scope.alloc(2), 2);
-    cdata.args[0] = target;
-    cdata.args[1] = id.isArrayIndex() ? Value::fromUInt32(id.asArrayIndex()).toString(scope.engine) : id.asStringOrSymbol();
+    Value *args = scope.alloc(2);
+    args[0] = target;
+    args[1] = id.isArrayIndex() ? Value::fromUInt32(id.asArrayIndex()).toString(scope.engine) : id.asStringOrSymbol();
+    JSCallData cdata(handler, args, 2);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
@@ -250,9 +254,10 @@ PropertyAttributes ProxyObject::virtualGetOwnProperty(const Managed *m, Property
         return Attr_Invalid;
     }
 
-    JSCallData cdata(handler, scope.alloc(2), 2);
-    cdata.args[0] = target;
-    cdata.args[1] = id.isArrayIndex() ? Value::fromUInt32(id.asArrayIndex()).toString(scope.engine) : id.asStringOrSymbol();
+    Value *args = scope.alloc(2);
+    args[0] = target;
+    args[1] = id.isArrayIndex() ? Value::fromUInt32(id.asArrayIndex()).toString(scope.engine) : id.asStringOrSymbol();
+    JSCallData cdata(handler, args, 2);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
@@ -325,10 +330,11 @@ bool ProxyObject::virtualDefineOwnProperty(Managed *m, PropertyKey id, const Pro
         return false;
     }
 
-    JSCallData cdata(handler, scope.alloc(3), 3);
-    cdata.args[0] = target;
-    cdata.args[1] = id.isArrayIndex() ? Value::fromUInt32(id.asArrayIndex()).toString(scope.engine) : id.asStringOrSymbol();
-    cdata.args[2] = ObjectPrototype::fromPropertyDescriptor(scope.engine, p, attrs);
+    Value *args = scope.alloc(3);
+    args[0] = target;
+    args[1] = id.isArrayIndex() ? Value::fromUInt32(id.asArrayIndex()).toString(scope.engine) : id.asStringOrSymbol();
+    args[2] = ObjectPrototype::fromPropertyDescriptor(scope.engine, p, attrs);
+    JSCallData cdata(handler, args, 3);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     bool result = !scope.engine->hasException && trapResult->toBoolean();
@@ -377,8 +383,9 @@ bool ProxyObject::virtualIsExtensible(const Managed *m)
     if (!trap->isFunctionObject())
         return scope.engine->throwTypeError();
 
-    JSCallData cdata(handler, scope.alloc(1), 1);
-    cdata.args[0] = target;
+    Value *args = scope.alloc(1);
+    args[0] = target;
+    JSCallData cdata(handler, args, 1);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
@@ -410,8 +417,9 @@ bool ProxyObject::virtualPreventExtensions(Managed *m)
     if (!trap->isFunctionObject())
         return scope.engine->throwTypeError();
 
-    JSCallData cdata(handler, scope.alloc(1), 1);
-    cdata.args[0] = target;
+    Value *args = scope.alloc(1);
+    args[0] = target;
+    JSCallData cdata(handler, args, 1);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
@@ -447,8 +455,9 @@ Heap::Object *ProxyObject::virtualGetPrototypeOf(const Managed *m)
         return nullptr;
     }
 
-    JSCallData cdata(handler, scope.alloc(1), 1);
-    cdata.args[0] = target;
+    Value *args = scope.alloc(1);
+    args[0] = target;
+    JSCallData cdata(handler, args, 1);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
@@ -491,9 +500,10 @@ bool ProxyObject::virtualSetPrototypeOf(Managed *m, const Object *p)
         return false;
     }
 
-    JSCallData cdata(handler, scope.alloc(2), 2);
-    cdata.args[0] = target;
-    cdata.args[1] = p ? p->asReturnedValue() : Encode::null();
+    Value *args = scope.alloc(2);
+    args[0] = target;
+    args[1] = p ? p->asReturnedValue() : Encode::null();
+    JSCallData cdata(handler, args, 2);
 
     ScopedValue trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     bool result = !scope.engine->hasException && trapResult->toBoolean();
@@ -584,8 +594,9 @@ OwnPropertyKeyIterator *ProxyObject::virtualOwnPropertyKeys(const Object *m, Val
         return nullptr;
     }
 
-    JSCallData cdata(handler, scope.alloc(1), 1);
-    cdata.args[0] = target;
+    Value *args = scope.alloc(1);
+    args[0] = target;
+    JSCallData cdata(handler, args, 1);
     ScopedObject trapResult(scope, static_cast<const FunctionObject *>(trap.ptr)->call(cdata));
     if (scope.engine->hasException)
         return nullptr;