public CaseLabel(Expression constant, AstNode children, TokenPosition position)
: base(position)
{
this.constant = constant;
this.children = children;
this.block = null;
}
public FunctionGenerator()
{
this.currentFunction = null;
this.currentBreak = null;
this.currentContinue = null;
this.currentExceptionContext = null;
this.builder = new BlockBuilder();
}
public void AddSuccessor(BasicBlock successor)
{
if(successors == null)
successors = new List<BasicBlock> ();
successors.Add(successor);
successor.AddPredecesor(this);
}
public ExceptionContext(ExceptionContext parentContext)
{
// Store parent-child relation.
this.parentContext = parentContext;
this.parentFunction = parentContext.parentFunction;
parentContext.children.Add(this);
module = parentFunction.GetModule();
// Initialize more variables.
this.children = new List<ExceptionContext> ();
this.blocks = new List<BasicBlock> ();
this.handlers = new List<Handler> ();
this.cleanup = null;
}
public void AddCatch(Structure exception, BasicBlock block)
{
foreach(Handler h in handlers)
{
if(h.exception == exception)
throw new ModuleException("Exception is already handled.");
}
// Store.
Handler ha = new Handler();
ha.exception = exception;
ha.handler = block;
handlers.Add(ha);
}
public ExceptionContext(Function parentFunction)
{
// Store parent-child relation.
this.parentContext = null;
this.parentFunction = parentFunction;
module = parentFunction.GetModule();
if(parentFunction.exceptionContext != null)
throw new ModuleException("A function only can have one (toplevel) exception context.");
parentFunction.exceptionContext = this;
// Initialize more variables.
this.children = new List<ExceptionContext> ();
this.blocks = new List<BasicBlock> ();
this.handlers = new List<Handler> ();
this.cleanup = null;
}
protected Function(ChelaModule module)
: base(module)
{
this.name = string.Empty;
this.flags = MemberFlags.Default;
this.parentScope = null;
this.basicBlocks = new List<BasicBlock> ();
this.lexicalScopes = new List<LexicalScope>();
this.locals = new List<LocalVariable> ();
this.position = null;
this.exceptionContext = null;
this.returnBlock = null;
this.returningVar = null;
this.returnValueVar = null;
this.genericPrototype = GenericPrototype.Empty;
this.arguments = null;
}
public override AstNode Visit(SwitchStatement node)
{
// Begin the node.
builder.BeginNode(node);
// Process the switch expression.
Expression switchExpr = node.GetConstant();
switchExpr.Accept(this);
// Perform coercion.
IChelaType switchType = switchExpr.GetNodeType();
IChelaType coercionType = node.GetCoercionType();
if(switchType != coercionType)
Cast(node, switchExpr.GetNodeValue(), switchType, coercionType);
// Create the merge block.
BasicBlock merge = CreateBasicBlock();
merge.SetName("smerge");
// Store the old break.
BasicBlock oldBreak = currentBreak;
currentBreak = merge;
// Initialize the default block to the merge.
BasicBlock defaultBlock = merge;
// Get the cases dictionary.
IDictionary<ConstantValue, CaseLabel> caseDictionary = node.CaseDictionary;
// Create the jump table.
int tableSize = caseDictionary.Count + 1;
int[] constants = new int[tableSize];
BasicBlock[] blocks = new BasicBlock[tableSize];
// The first element is always the default block.
int i = 0;
constants[i] = -1;
blocks[i] = defaultBlock; ++i;
// Add the other elements.
BasicBlock caseBlock = null;
CaseLabel label = (CaseLabel)node.GetCases();
while(label != null)
{
// Create the label block.
if(caseBlock == null)
{
caseBlock = CreateBasicBlock();
caseBlock.SetName("caseBlock");
}
// Set the label block.
label.SetBlock(caseBlock);
// Store the default block.
if(label.GetConstant() == null)
{
defaultBlock = caseBlock;
blocks[0] = caseBlock;
}
else
{
// Append it to the jump table.
Expression caseExpr = label.GetConstant();
ConstantValue caseConstant = (ConstantValue)caseExpr.GetNodeValue();
constants[i] = caseConstant.GetIntValue();
blocks[i] = caseBlock;
++i;
}
// Create a new block if the last case wasn't empty.
if(label.GetChildren() != null)
caseBlock = null;
// Process the next label.
label = (CaseLabel)label.GetNext();
}
// Perform the switch.
BasicBlock switchBlock = builder.GetBlock();
builder.CreateSwitch(constants, blocks);
// Generate the cases blocks.
VisitList(node.GetCases());
// Continue with the normal flow.
currentBreak = oldBreak;
// Remove the merge block if its unreachable.
if(merge.GetPredsCount() == 0)
{
builder.SetBlock(switchBlock);
merge.Destroy();
if(node.GetNext() != null)
Warning(node.GetNext(), "detected unreachable code.");
node.SetNext(null);
}
else
{
builder.SetBlock(merge);
}
return builder.EndNode();
}
private Method CreateTrivialConstructor(Structure building, Structure buildingInstance)
{
// Create the constructor function type.
FunctionType type = FunctionType.Create(ChelaType.GetVoidType(),
new IChelaType[]{ReferenceType.Create(buildingInstance)}, false);
// Create the constructor.
Method ctor = new Method(".ctor", MemberFlags.Public | MemberFlags.Constructor, building);
ctor.SetFunctionType(type);
building.AddFunction(".ctor", ctor);
// Create the constructor block.
BasicBlock top = new BasicBlock(ctor);
top.SetName("top");
top.Append(new Instruction(OpCode.RetVoid, null));
return ctor;
}
private void PrepareReturning(AstNode where, Function function, LexicalScope scope)
{
// Get the definition node and check for generator.
FunctionDefinition defNode = function.DefinitionNode;
bool isGenerator = false;
if(defNode != null)
isGenerator = defNode.IsGenerator;
// Use standard return.
if(function.GetExceptionContext() == null && !isGenerator)
return;
// Create the return block.
BasicBlock returnBlock = new BasicBlock(function);
returnBlock.SetName("retBlock");
function.ReturnBlock = returnBlock;
// Create the return value local.
FunctionType functionType = function.GetFunctionType();
IChelaType retType = functionType.GetReturnType();
if(retType != ChelaType.GetVoidType() && !isGenerator)
function.ReturnValueVar = new LocalVariable(GenSym() + "_retval", scope, retType);
// Create the is returning flag.
function.ReturningVar = new LocalVariable(GenSym() + "_isret", scope, ChelaType.GetBoolType(), isGenerator);
function.ReturningVar.Type = LocalType.Return;
// Create the field for generators.
if(isGenerator)
{
FieldVariable returningField = new FieldVariable("returning", MemberFlags.Private,
ChelaType.GetBoolType(), defNode.GeneratorClass);
defNode.GeneratorClass.AddField(returningField);
function.ReturningVar.ActualVariable = returningField;
}
// Initializer the returning flag to false.
builder.CreateLoadBool(false);
PerformAssignment(where, function.ReturningVar);
}
private void CreateGenerator_Reset(FunctionDefinition node)
{
// Get the generator class.
Class genClass = node.GeneratorClass;
// Create the function type.
FunctionType functionType =
FunctionType.Create(ChelaType.GetVoidType(),
new IChelaType[]{ReferenceType.Create(node.GeneratorClassInstance)}, false);
// Create the method.
Method method = new Method("Reset", MemberFlags.Public, genClass);
method.SetFunctionType(functionType);
genClass.AddFunction("Reset", method);
// Create the top block.
BasicBlock top = new BasicBlock(method);
builder.SetBlock(top);
// Throw an exception.
Class excpt = (Class)ExtractClass(node, currentModule.GetLangMember("InvalidOperationException"));
builder.CreateLoadString("IEnumerator.Reset cannot be called in generators.");
builder.CreateNewObject(excpt, GetExceptionCtor(node, excpt), 1);
builder.CreateThrow();
}
private void CreateStaticConstructor(AstNode node, Namespace space)
{
// Check for a previous definition.
if(space.GetStaticConstructor() != null || space.GetGlobalInitializations() == null)
return;
// Get the static initialization fields.
List<FieldDeclaration> staticInitedField = new List<FieldDeclaration> ();
bool isUnsafe = false;
foreach(FieldDeclaration decl in space.GetGlobalInitializations())
{
Variable variable = decl.GetVariable();
if(variable.IsStatic())
{
staticInitedField.Add(decl);
if(variable.IsUnsafe())
isUnsafe = true;
}
}
// If there aren't field to initialize, don't create the static constructor.
if(staticInitedField.Count == 0)
return;
// Create the static constructor function type.
FunctionType ctorType = FunctionType.Create(ChelaType.GetVoidType());
// Create the constructor method.
MemberFlags flags = MemberFlags.StaticConstructor;
if(isUnsafe)
flags |= MemberFlags.Unsafe;
Function constructor = new Function("<sctor>", flags, space);
constructor.SetFunctionType(ctorType);
// Store it.
space.AddMember(constructor);
// Create the constructor scope.
LexicalScope ctorScope = CreateLexicalScope(node, constructor);
PushScope(ctorScope);
// Create the top basic block.
BasicBlock topBlock = new BasicBlock(constructor);
builder.SetBlock(topBlock);
// Initialize the static fields.
GenerateStaticFieldInitializations(null, staticInitedField);
// Restore the scope.
PopScope();
// Return void.
builder.CreateRetVoid();
}
public void SetBlock(BasicBlock block)
{
this.block = block;
}
public void SetCleanup(BasicBlock block)
{
this.cleanup = block;
}
private void AddPredecesor(BasicBlock pred)
{
if(preds == null)
preds = new List<BasicBlock> ();
preds.Add(pred);
}
public void SetBlock(BasicBlock block)
{
// Set the block.
this.currentBlock = block;
}
private void CreateDefaultConstructor(StructDefinition node)
{
// Get the structure, and the default constructor.
Structure building = node.GetStructure();
Method constructor = node.GetDefaultConstructor();
// Ignore structures without a default constructor.
if(constructor == null)
return;
// Crete the self scope.
LexicalScope selfScope = CreateLexicalScope(node, constructor);
new ArgumentVariable(0, "this", selfScope, ReferenceType.Create(building));
PushScope(selfScope);
// Create the top basic block.
BasicBlock topBlock = new BasicBlock(constructor);
builder.SetBlock(topBlock);
// Add implicit construction expressions.
CreateImplicitBaseConstructor(node, constructor);
// Initialize some field.
GenerateFieldInitializations(node, building);
// Restore the scope.
PopScope();
// Return void.
builder.CreateRetVoid();
}
internal int AddBlock(BasicBlock block)
{
int ret = this.basicBlocks.Count;
this.basicBlocks.Add(block);
return ret;
}
private BasicBlock CreateBasicBlock()
{
BasicBlock ret = new BasicBlock(currentFunction);
ret.IsUnsafe = IsUnsafe;
if(currentExceptionContext != null)
currentExceptionContext.AddBlock(ret);
return ret;
}
public void RemoveBlock(BasicBlock block)
{
// Remove it from my blocks.
for(int i = 0; i < blocks.Count; ++i)
{
if(blocks[i] == block)
{
blocks.RemoveAt(i);
break;
}
}
// Remove it from my handlers.
for(int i = 0; i < handlers.Count; ++i)
{
Handler h = (Handler)handlers[i];
if(h.handler == block)
{
handlers.RemoveAt(i);
break;
}
}
// Remove it from my cleanup.
if(cleanup == block)
cleanup = null;
// Remove it from my children.
foreach(ExceptionContext child in children)
child.RemoveBlock(block);
}
public override AstNode Visit(ForStatement node)
{
// Begin the node.
builder.BeginNode(node);
// Get the for elements.
AstNode decl = node.GetDecls();
AstNode cond = node.GetCondition();
AstNode incr = node.GetIncr();
// Write the declaration.
if(decl != null)
decl.Accept(this);
// Create the basics blocks.
BasicBlock forStart = CreateBasicBlock();
BasicBlock forEnd = CreateBasicBlock();
BasicBlock forBreak = CreateBasicBlock();
BasicBlock forCond = forStart;
// Set the blocks names.
forStart.SetName("for_start");
forEnd.SetName("for_end");
forBreak.SetName("for_break");
// Store and update the break and continue points.
BasicBlock oldBreak = currentBreak;
BasicBlock oldContinue = currentContinue;
currentBreak = forBreak;
currentContinue = forEnd;
// Write the condition.
if(cond != null)
{
// Create the condition block.
forCond = CreateBasicBlock();
forCond.SetName("for_cond");
// Jump into the condition.
builder.CreateJmp(forCond);
builder.SetBlock(forCond);
// Write the condition.
cond.Accept(this);
// Cast the condition.
IChelaType condType = cond.GetNodeType();
if(condType != ChelaType.GetBoolType())
Cast(node, cond.GetNodeValue(), condType, ChelaType.GetBoolType());
// Perform the conditional branch.
builder.CreateBr(forStart, forBreak);
}
else
{
// Jump into the beginning of the loop.
builder.CreateJmp(forStart);
}
// Write the loop content.
builder.SetBlock(forStart);
VisitList(node.GetChildren());
// Branch into the loop end.
if(!builder.IsLastTerminator())
builder.CreateJmp(forEnd);
// Write the for end.
builder.SetBlock(forEnd);
// Write the increment.
if(incr != null)
incr.Accept(this);
// Branch into the condition.
if(!builder.IsLastTerminator())
builder.CreateJmp(forCond);
// Continue with the rest of the program.
builder.SetBlock(forBreak);
// Restore the break and continue point.
currentBreak = oldBreak;
currentContinue = oldContinue;
return builder.EndNode();
}
public override AstNode Visit(DoWhileStatement node)
{
// Begin the node.
builder.BeginNode(node);
// Get the condition and the job.
Expression cond = node.GetCondition();
AstNode job = node.GetJob();
// Create the basic blocks.
BasicBlock condBlock = CreateBasicBlock();
BasicBlock contentBlock = CreateBasicBlock();
BasicBlock endBlock = CreateBasicBlock();
// Set the blocks names.
condBlock.SetName("cond");
contentBlock.SetName("content");
endBlock.SetName("end");
// Store the old break and continue.
BasicBlock oldBreak = currentBreak;
BasicBlock oldContinue = currentContinue;
// Set the new break and continue.
currentBreak = endBlock;
currentContinue = condBlock;
// Branch into the content.
builder.CreateJmp(contentBlock);
// Write the content.
builder.SetBlock(contentBlock);
job.Accept(this);
// Branch into the condition.
if(!builder.IsLastTerminator())
builder.CreateJmp(condBlock);
// Write the condition.
builder.SetBlock(condBlock);
cond.Accept(this);
// Cast the condition.
IChelaType condType = cond.GetNodeType();
if(condType != ChelaType.GetBoolType())
Cast(node, cond.GetNodeValue(), condType, ChelaType.GetBoolType());
// Close the loop.
builder.CreateBr(contentBlock, endBlock);
// Continue with the normal flow.
builder.SetBlock(endBlock);
// Restore the break and continue blocks.
currentBreak = oldBreak;
currentContinue = oldContinue;
return builder.EndNode();
}
private void CreateGenerator_GetEnumerator(FunctionDefinition node, Structure enumeratorType, bool generic)
{
// Get the generator class.
Class genClass = node.GeneratorClass;
// Use the GetEnumerator name for the most specific version.
string name = "GetEnumerator";
Function contract = null;
if(!generic && node.IsGenericIterator)
{
name = GenSym();
contract = FindFirstConstract(currentModule.GetEnumerableIface(), "GetEnumerator");
}
// Create the function type.
FunctionType functionType =
FunctionType.Create(ReferenceType.Create(enumeratorType),
new IChelaType[]{ReferenceType.Create(node.GeneratorClassInstance)}, false);
// Create the method.
Method method = new Method(name, MemberFlags.Public, genClass);
method.SetFunctionType(functionType);
genClass.AddFunction(name, method);
// Set the explicit contract.
if(contract != null)
method.SetExplicitContract(contract);
// Create the method block.
BasicBlock block = new BasicBlock(method);
block.SetName("top");
// Return this.
builder.SetBlock(block);
builder.CreateLoadArg(0);
builder.CreateRet();
}
public void CreateBr(BasicBlock trueDest, BasicBlock falseDest)
{
AppendInst2(OpCode.Br, trueDest, falseDest);
currentBlock.AddSuccessor(trueDest);
currentBlock.AddSuccessor(falseDest);
}
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;
}
private void CreateDefaultStaticConstructor(StructDefinition node)
{
// Get the structure.
Structure building = node.GetStructure();
// Check for an user defined constructor.
if(building.GetStaticConstructor() != null)
return;
// Get the static initialization fields.
List<FieldDeclaration> staticInitedField = new List<FieldDeclaration> ();
bool isUnsafe = false;
foreach(FieldDeclaration decl in building.GetFieldInitializations())
{
Variable variable = decl.GetVariable();
if(variable.IsStatic())
{
staticInitedField.Add(decl);
if(variable.IsUnsafe())
isUnsafe = true;
}
}
// If there aren't field to initialize, don't create the static constructor.
if(staticInitedField.Count == 0)
return;
// Begin the node.
builder.BeginNode(node);
// Create the static constructor function type.
FunctionType ctorType = FunctionType.Create(ChelaType.GetVoidType());
// Create the constructor method.
MemberFlags flags = MemberFlags.StaticConstructor;
if(isUnsafe)
flags |= MemberFlags.Unsafe;
Method constructor = new Method("<sctor>", flags, building);
constructor.SetFunctionType(ctorType);
// Store it.
building.AddFunction("<sctor>", constructor);
// Create the constructor scope.
LexicalScope ctorScope = CreateLexicalScope(node, constructor);
PushScope(ctorScope);
// Create the top basic block.
BasicBlock topBlock = new BasicBlock(constructor);
builder.SetBlock(topBlock);
// Initialize the static fields.
GenerateStaticFieldInitializations(node, staticInitedField);
// Restore the scope.
PopScope();
// Return void.
builder.CreateRetVoid();
// End the node.
builder.EndNode();
}
public void AddBlock(BasicBlock block)
{
blocks.Add(block);
}
internal void RemoveBasicBlock(BasicBlock block)
{
// Displace the upper blocks.
int numblocks = basicBlocks.Count;
for(int i = block.blockIndex; i < numblocks-1; ++i)
{
BasicBlock next = (BasicBlock)basicBlocks[i+1];
next.blockIndex = i;
basicBlocks[i] = next;
}
// Remove the last block.
basicBlocks.RemoveAt(numblocks-1);
// Remove the block from the exception contexts
if(exceptionContext != null)
exceptionContext.RemoveBlock(block);
}
private void CreateGenerator_Current(FunctionDefinition node, bool generic)
{
// Get the generator class.
Class genClass = node.GeneratorClass;
// Use the get_Current name for the most specific version.
string name = "get_Current";
Function contract = null;
if(!generic && node.IsGenericIterator)
{
name = GenSym();
contract = FindFirstConstract(currentModule.GetEnumeratorIface(), "get_Current");
}
// Select the current type.
IChelaType currentType = node.YieldType;
if(!generic)
currentType = ReferenceType.Create(currentModule.GetObjectClass());
// Create the function type.
FunctionType functionType =
FunctionType.Create(currentType,
new IChelaType[]{ReferenceType.Create(node.GeneratorClassInstance)}, false);
// Create the method.
Method method = new Method(name, MemberFlags.Public, genClass);
method.SetFunctionType(functionType);
genClass.AddFunction(name, method);
// Set the explicit contract.
if(contract != null)
method.SetExplicitContract(contract);
// Create the method block.
BasicBlock block = new BasicBlock(method);
block.SetName("top");
// Create the return and error blocks.
BasicBlock retBlock = new BasicBlock(method);
retBlock.SetName("ret");
BasicBlock errorBlock = new BasicBlock(method);
errorBlock.SetName("error");
// Make sure reset was called before the first Current.
builder.SetBlock(block);
builder.CreateLoadArg(0);
builder.CreateLoadField(node.GeneratorState);
builder.CreateLoadInt32(0);
builder.CreateCmpEQ();
builder.CreateBr(errorBlock, retBlock);
// Raise an error if reset wasn't called.
builder.SetBlock(errorBlock);
Class excpt = (Class)ExtractClass(node, currentModule.GetLangMember("InvalidOperationException"));
builder.CreateLoadString("IEnumerator.MoveNext must be called before than IEnumerator.Current.");
builder.CreateNewObject(excpt, GetExceptionCtor(node, excpt), 1);
builder.CreateThrow();
// Load the yielded value.
builder.SetBlock(retBlock);
builder.CreateLoadArg(0);
builder.CreateLoadField(node.YieldedValue);
// Cast the yielded value.
Cast(node, null, node.YieldType, currentType);
// Return.
builder.CreateRet();
}
private void CreateGenerator_Dispose(FunctionDefinition node, Function moveNext)
{
// Get the generator class.
Class genClass = node.GeneratorClass;
// Create the function type.
FunctionType functionType =
FunctionType.Create(ChelaType.GetVoidType(),
new IChelaType[]{ReferenceType.Create(node.GeneratorClassInstance)}, false);
// Create the method.
Method method = new Method("Dispose", MemberFlags.Public, genClass);
method.SetFunctionType(functionType);
genClass.AddFunction("Dispose", method);
// Create the top block.
BasicBlock top = new BasicBlock(method);
builder.SetBlock(top);
// Create the return and dispose blocks.
BasicBlock justReturn = new BasicBlock(method);
BasicBlock disposeAndReturn = new BasicBlock(method);
// Load the current state.
builder.CreateLoadArg(0);
builder.CreateDup1();
builder.CreateDup1();
builder.CreateLoadField(node.GeneratorState);
builder.CreateDup1();
builder.CreateLoadInt32(1);
builder.CreateCmpEQ();
builder.CreateBr(justReturn, disposeAndReturn);
// Dispose and return implementation.
builder.SetBlock(disposeAndReturn);
// Increase the state.
builder.CreateLoadInt32(1);
builder.CreateAdd();
builder.CreateStoreField(node.GeneratorState);
// Call move next.
builder.CreateCall(moveNext, 1);
builder.CreateRetVoid();
// Just return implementation.
builder.SetBlock(justReturn);
builder.CreateRetVoid();
}
private void EmitBasicBlockDebugInfo(ModuleWriter writer, BasicBlock block)
{
// Compute instructions subblocks.
List <SubBlock> subBlocks = new List <SubBlock> ();
TokenPosition position = NullPosition;
int start = 0;
int index = 0;
foreach (Instruction inst in block.GetInstructions())
{
// Get the instruction position.
TokenPosition instPos = inst.GetPosition();
if (instPos == null)
{
instPos = NullPosition;
}
if (instPos != position)
{
// Create a sub block for the previous set.
if (index != 0)
{
SubBlock subBlock = new SubBlock();
subBlock.Position = position;
subBlock.Start = (ushort)start;
subBlock.End = (ushort)(index - 1);
// Store the sub block.
subBlocks.Add(subBlock);
}
// Store the start of the next subblock.
start = index;
position = instPos;
}
// Increase the index.
++index;
}
// Create the last sub block.
SubBlock lastSubBlock = new SubBlock();
lastSubBlock.Position = position;
lastSubBlock.Start = (ushort)(start);
lastSubBlock.End = (ushort)(index - 1);
// Store the sub block.
subBlocks.Add(lastSubBlock);
// Emit all of the sub blocks.
ushort numSubs = (ushort)subBlocks.Count;
writer.Write(numSubs);
foreach (SubBlock subBlock in subBlocks)
{
writer.Write(subBlock.Start);
writer.Write(subBlock.End);
EmitPosition(writer, subBlock.Position);
}
}