public Function(CodeGeneratorContext genContext, FunctionDefinitionNode leaf)
{
_leaf = leaf;
// Create function type and add the function node without appending any basic blocks
// This results in a function declaration in LLVM-IR
Type[] paramTypes =
Array.ConvertAll(leaf.Parameters, param => genContext.LookupType(param.Type) !.Value);
FunctionType =
genContext.Context.FunctionType(genContext.LookupType(leaf.ReturnType) !.Value, paramTypes, false);
FunctionValue = genContext.Module.AddFunction(leaf.Name, FunctionType);
// Process the static keyword in the same manner as clang
FunctionValue.SetLinkage(leaf.IsExported
? LLVMLinkage.LLVMExternalLinkage
: LLVMLinkage.LLVMInternalLinkage);
genContext.TryGetNodeSymbol(leaf, out Symbol range);
DiFwdDecl = genContext.DiBuilder.CreateReplaceableCompositeType(
LLVMDWARFTag.subroutine_type, leaf.Name, genContext.DiFile, genContext.DiFile,
range.LLVMLine, 0, 0, 0, LLVMDIFlags.LLVMDIFlagFwdDecl, "");
}
/// <summary>
/// Add entry basic block to this function and fill in additional debug info.
/// If not called, this is a function declaration.
/// </summary>
/// <param name="genContext"></param>
/// <param name="builder"></param>
/// <returns>Entry basic block</returns>
public BasicBlock StartDefinition(CodeGeneratorContext genContext, Builder builder)
{
BasicBlock basicBlock = genContext.Context.AppendBasicBlock(FunctionValue, "entry");
builder.PositionAtEnd(basicBlock);
// Build return value storage if necessary
Type returnType = FunctionType.ReturnType;
if (returnType.Kind != LLVMTypeKind.LLVMVoidTypeKind)
{
ReturnBlock = genContext.Context.CreateBasicBlock("return");
RetvalStorage = builder.BuildAlloca(returnType, "retval");
}
// Visit all declaration nodes and create storage (parameters and variables)
StackLayoutGenerator layoutGenerator = new StackLayoutGenerator(new IndexTypeSizeManager());
layoutGenerator.VisitFunctionDefinition(_leaf);
FunctionStackLayout layout = layoutGenerator.GetLayout();
foreach (var v in layout.Variables)
{
Type varType = genContext.LookupType(v.Key.Type) !.Value;
Value varStorage = builder.BuildAlloca(varType, v.Key.Name);
VariableValues[v.Key] = varStorage;
}
// Emit store instruction for return value
if (RetvalStorage != null && !returnType.IsStructType())
{
builder.BuildStore(Value.ConstInt(returnType, 0, true), RetvalStorage.Value);
}
// Emit store instructions for parameters
Value[] funcParams = FunctionValue.Params;
for (int i = 0, ilen = funcParams.Length; i < ilen; ++i)
{
DeclarationNode parameter = _leaf.Parameters[i];
Value paramValue = funcParams[i];
VariableValues.TryGetValue(parameter, out Value varStorage);
varStorage.SetName($"{parameter.Name}.addr");
builder.BuildStore(paramValue, varStorage);
paramValue.SetName(parameter.Name);
}
// Create subroutine type debug info
genContext.TryGetNodeSymbol(_leaf, out Symbol range);
Metadata subroutineType = genContext.DiBuilder.CreateSubroutineType(genContext.DiFile,
Array.ConvertAll(_leaf.Parameters, param => genContext.LookupDiType(param.Type) !.Value),
LLVMDIFlags.LLVMDIFlagZero);
Metadata funcLocation = genContext.Context.CreateDebugLocation(range.LLVMLine,
genContext.ColumnInfo ? range.LLVMColumn : 0, DiFwdDecl, Metadata.Null);
// Create subroutine debug info and substitute over forward declaration
DiFunctionDef = genContext.DiBuilder.CreateFunction(genContext.DiFile, _leaf.Name, _leaf.Name,
genContext.DiFile, range.LLVMLine, subroutineType, true, true, range.LLVMLine,
LLVMDIFlags.LLVMDIFlagZero, false);
DiFwdDecl.ReplaceAllUsesWith(DiFunctionDef);
// Create llvm.dbg.declare calls for each parameter's storage
if (genContext.DebugInfo)
{
Metadata paramExpression = genContext.DiBuilder.CreateExpression();
for (int i = 0, ilen = _leaf.Parameters.Length; i < ilen; ++i)
{
DeclarationNode parameter = _leaf.Parameters[i];
genContext.TryGetNodeSymbol(parameter, out Symbol paramRange);
Metadata paramType = genContext.LookupDiType(parameter.Type) !.Value;
Metadata paramMetadata = genContext.DiBuilder.CreateParameterVariable(DiFunctionDef,
parameter.Name, (uint)i + 1, genContext.DiFile, paramRange.LLVMLine, paramType, true,
LLVMDIFlags.LLVMDIFlagZero);
VariableValues.TryGetValue(parameter, out Value varStorage);
genContext.DiBuilder.InsertDeclareAtEnd(varStorage, paramMetadata, paramExpression,
funcLocation, basicBlock);
}
}
// Associate debug info nodes with function
FunctionValue.SetFuncSubprogram(DiFunctionDef);
return(basicBlock);
}