public Construct VisitExtern(Extern node)
{
// Ensure prototype is set.
if (node.Prototype == null)
{
throw new Exception("Unexpected external definition's prototype to be null");
}
// Create the argument buffer list.
List <LlvmType> arguments = new List <LlvmType>();
// TODO: What about reference? Arguments must be named for extern?
foreach ((Kind kind, Reference reference) in node.Prototype.Arguments)
{
// Visit the kind.
this.VisitKind(kind);
// Pop the type off the stack.
LlvmType argumentType = this.typeStack.Pop();
// Append onto the arguments list.
arguments.Add(argumentType);
}
// Visit the prototype's return kind.
this.Visit(node.Prototype.ReturnKind);
// Pop the return type off the stack.
LlvmType returnType = this.typeStack.Pop();
// Emit the function type.
LlvmType type = LlvmFactory.Function(returnType, arguments.ToArray(), node.Prototype.HasInfiniteArguments);
// Emit the external definition to context and capture the LLVM value reference.
LlvmValue @extern = this.module.CreateFunction(node.Prototype.Identifier, type);
// Determine if should be registered on the symbol table.
if (!this.module.ContainsFunction(node.Prototype.Identifier))
{
// Register the external definition as a function in the symbol table.
this.module.RegisterFunction((LlvmFunction)@extern);
}
// Otherwise, throw an error.
else
{
throw new Exception($"Warning: Extern definition '{node.Prototype.Identifier}' being re-defined");
}
// Push the resulting value onto the stack.
this.valueStack.Push(@extern);
// Return the node.
return(node);
}
public Construct VisitPrototype(Prototype node)
{
// Retrieve argument count within node.
uint argumentCount = (uint)node.Arguments.Length;
// Create the argument buffer array.
LlvmType[] arguments = new LlvmType[Math.Max(argumentCount, 1)];
// Attempt to retrieve an existing function value.
LlvmFunction?function = this.module.GetFunction(node.Identifier);
// Function may be already defined.
if (function != null)
{
// Function already has a body, disallow re-definition.
if (function.HasBlocks)
{
throw new Exception($"Cannot re-define function: {node.Identifier}");
}
// If the function takes a different number of arguments, reject.
else if (function.ArgumentCount != argumentCount)
{
throw new Exception("redefinition of function with different # args");
}
}
else
{
// TODO: Wrong type.
for (int i = 0; i < argumentCount; ++i)
{
arguments[i] = LLVM.DoubleType().Wrap();
}
// TODO: Support for infinite arguments and hard-coded return type.
// Create the function type.
LlvmType type = LlvmFactory.Function(LlvmFactory.Void(), arguments, false);
// Create the function within the module.
function = this.module.CreateFunction(node.Identifier, type);
// Set the function's linkage.
function.SetLinkage(LLVMLinkage.LLVMExternalLinkage);
}
// Process arguments.
for (int i = 0; i < argumentCount; ++i)
{
// Retrieve the argument name.
string argumentName = node.Arguments[i].Item2.Value;
// Retrieve the argument at the current index iterator.
LlvmValue argument = function.GetArgumentAt((uint)i);
// Name the argument.
argument.SetName(argumentName);
// TODO: Watch out for already existing ones.
// Stored the named argument in the named values cache.
this.namedValues.Add(argumentName, argument);
}
// Push the function onto the stack.
this.valueStack.Push(function);
// Return the node.
return(node);
}
public Construct VisitRoutine(Routine node)
{
// Ensure body was provided or created.
if (node.Body == null)
{
throw new Exception("Unexpected function body to be null");
}
// Ensure prototype is set.
else if (node.Prototype == null)
{
throw new Exception("Unexpected function prototype to be null");
}
// Ensures the function does not already exist.
else if (this.module.ContainsFunction(node.Prototype.Identifier))
{
throw new Exception($"A function with the identifier '{node.Prototype.Identifier}' already exists");
}
// Clear named values.
this.namedValues.Clear();
// Create an argument buffer list.
List <LlvmType> arguments = new List <LlvmType>();
// Process the prototype's arguments.
foreach ((Kind kind, Reference reference) in node.Prototype.Arguments)
{
// Visit the argument's type.
this.Visit(kind);
// Pop the resulting type off the stack.
LlvmType argumentType = this.typeStack.Pop();
// Append the argument's type to the argument list.
arguments.Add(argumentType);
}
// Visit the return type node.
this.Visit(node.Prototype.ReturnKind);
// Pop off the return type off the stack.
LlvmType returnType = this.typeStack.Pop();
// Emit the function type.
LlvmType type = LlvmFactory.Function(returnType, arguments.ToArray(), node.Prototype.HasInfiniteArguments);
// Create the function.
LlvmFunction function = this.module.CreateFunction(node.Prototype.Identifier, type);
// Register as the temporary, local function.
this.function = function;
// Create the argument index counter.
uint argumentIndexCounter = 0;
// Name arguments.
foreach ((Kind kind, Reference reference) in node.Prototype.Arguments)
{
// Retrieve the argument.
LlvmValue argument = function.GetArgumentAt(argumentIndexCounter);
// Name the argument.
argument.SetName(reference.Value);
// Increment the index counter for next iteration.
argumentIndexCounter++;
}
// Visit the body.
this.VisitSection(node.Body);
// Pop the body off the stack.
this.blockStack.Pop();
// TODO
// Ensure that body returns a value if applicable.
// else if (!node.Prototype.ReturnKind.IsVoid && !node.Body.HasReturnValue)
// {
// throw new Exception("Functions that do not return void must return a value");
// }
// Verify the function.
function.Verify();
// Append the function onto the stack.
this.valueStack.Push(function);
// Return the node.
return(node);
}