private Function CreateGenerator_MoveNext(FunctionDefinition node)
{
// Get the generator class.
Class genClass = node.GeneratorClass;
// Create the function type.
FunctionType functionType =
FunctionType.Create(ChelaType.GetBoolType(),
new IChelaType[]{ReferenceType.Create(node.GeneratorClassInstance)}, false);
// Create the method.
Method method = new Method("MoveNext", MemberFlags.Public, genClass);
method.SetFunctionType(functionType);
method.DefinitionNode = node;
genClass.AddFunction("MoveNext", method);
// Swap the exception contexts.
method.SwapExceptionContexts(currentFunction);
// Store the old function.
Function oldFunction = currentFunction;
currentFunction = method;
// Create the jump table block.
BasicBlock jmpBlock = CreateBasicBlock();
jmpBlock.SetName("jmp");
// Generate the main code.
BasicBlock topBlock = CreateBasicBlock();
topBlock.SetName("top");
builder.SetBlock(topBlock);
// Prepare returning.
LexicalScope topScope = (LexicalScope) node.GetScope();
PrepareReturning(node, currentFunction, topScope);
// Create the function body.
VisitList(node.GetChildren());
// Finish returning.
FinishReturn(node, currentFunction);
// Create the state jump table.
builder.SetBlock(jmpBlock);
// Load the current state.
builder.CreateLoadArg(0);
builder.CreateLoadField(node.GeneratorState);
// Build the jump table.
int numstates = node.Yields.Count*2+3;
int[] stateConstants = new int[numstates];
BasicBlock[] stateEntries = new BasicBlock[numstates];
// The default case is return.
stateConstants[0] = -1;
stateEntries[0] = currentFunction.ReturnBlock;
// The first state is the top block.
stateConstants[1] = 0;
stateEntries[1] = topBlock;
// The second state is the return block.
stateConstants[2] = 1;
stateEntries[2] = currentFunction.ReturnBlock;
// The next states are the yield merges followed by yield disposes.
for(int i = 0; i < node.Yields.Count; ++i)
{
ReturnStatement yieldStmnt = node.Yields[i];
// Emit the merge state.
int stateId = i*2+2;
int entryIndex = stateId+1;
stateConstants[entryIndex] = stateId;
stateEntries[entryIndex] = yieldStmnt.MergeBlock;
// Emit the dispose state.
stateConstants[entryIndex+1] = stateId+1;
stateEntries[entryIndex+1] = yieldStmnt.DisposeBlock;
}
builder.CreateSwitch(stateConstants, stateEntries);
// Restore the old function.
currentFunction = oldFunction;
return method;
}
