/// <summary>
/// Performs addition on 2 StackValues
/// This is used by the VM when adding strings
/// </summary>
/// <param name="sv1"></param>
/// <param name="sv2"></param>
/// <returns></returns>
public static StackValue AddStackValueString(StackValue sv1, StackValue sv2, RuntimeCore runtimeCore)
{
Validity.Assert(sv1.IsString || sv2.IsString);
if (sv1.IsString && sv2.IsString)
{
return(StringUtils.ConcatString(sv2, sv1, runtimeCore));
}
else if (sv1.IsString || sv2.IsString)
{
StackValue newSV;
if (sv1.IsNull || sv2.IsNull)
{
return(StackValue.BuildNull());
}
else if (sv1.IsString)
{
newSV = StringUtils.ConvertToString(sv2, runtimeCore, runtimeCore.RuntimeMemory);
return(StringUtils.ConcatString(newSV, sv1, runtimeCore));
}
else if (sv2.IsString)
{
newSV = StringUtils.ConvertToString(sv1, runtimeCore, runtimeCore.RuntimeMemory);
return(StringUtils.ConcatString(sv2, newSV, runtimeCore));
}
}
return(StackValue.BuildNull());
}
public void TestGCStringCleanup()
{
// Simulating the following graph
/*
* def generateString() {
* return 1+"@" +2;
* };
*
* vv = [Imperative]{
* generateString();
* // "1@2" will be on the heap
* // current stack has no reference type elements
* // --------------------------------GC kicks in due to mem threshold----------------------------
* // "1@2" on the heap will be marked as white - since no stack elements have a reference to it
* //
* // Async VM execution computes a new generateString() fn Call
* cc = generateString();
* //
* // cc is pushed on the stack and holds a reference to the "1@2" heap element
* //
* // GC starts the sweep process in which it deletes "1@2" heap element
* // ----------------------------------GC is finished---------------------------------------------
* return cc;
* };
* //
* // vv is still on the stack with a reference to a now null heap element
*/
var heap = new Heap();
string sseValue = "hello world";
// Allocate a string on the heap.
// Similar to what would happen if a string stack element was pushed on the stack and then popped (due to out of scope).
heap.AllocateString(sseValue);
StackValue someStackValue = StackValue.BuildNull();
var notifications = new Dictionary <Heap.GCState, (Action, Action)>()
{
{
Heap.GCState.Sweep,
(() => {
// Simulate a new string (with the same value as existing one on heap) stack element being created while GC is propagating or sweeping
someStackValue = heap.AllocateString(sseValue);
},
() => { })
}
};
// Start GC with a random stack value as gcRoot (not the string stack element, because it was pushed out of the stack)
heap.FullGCTest(new List <StackValue>()
{
StackValue.BuildInt(1)
}, testExecutive, notifications);
// The stack element that was pushed after GC start should be valid.
Assert.IsNotNull(heap.ToHeapObject <DSString>(someStackValue));
}
public static StackValue BuildStackValueForPrimitive(AssociativeNode node)
{
Validity.Assert(IsPrimitiveASTNode(node) == true);
if (node is IntNode)
{
return(StackValue.BuildInt((node as IntNode).Value));
}
else if (node is DoubleNode)
{
return(StackValue.BuildDouble((node as DoubleNode).Value));
}
else if (node is BooleanNode)
{
return(StackValue.BuildBoolean((node as BooleanNode).Value));
}
return(StackValue.BuildNull());
}