public LLVMValueRef BuildCast(LLVMBuilderRef builder, LLVMValueRef elem, LLVMTypeRef targetType)
{
// Check if the type of the element equals the targe type
if (CompareType(elem, targetType))
{
// There is no need to cast
// Just return the element
return(elem);
}
// Strings need special handling
if (CompareType(targetType, StringType))
{
LLVMValueRef indices;
var gep = LLVM.BuildGEP(builder, elem, out indices, 0u, "tmpgep");
var ptr = LLVM.BuildPointerCast(builder, gep, StringType, "tmpptrcast");
return(ptr);
}
string strtype1, strtype2;
switch (targetType.TypeKind)
{
case LLVMTypeKind.LLVMIntegerTypeKind:
// Check if the integer fits
if (IsInteger(elem))
{
var lwidth = elem.TypeOf().GetIntTypeWidth();
var rwidth = targetType.GetIntTypeWidth();
if (lwidth > rwidth)
{
// The width of the result type is higher
// than the width of the element type
// Throw an exception
strtype1 = elem.TypeOf().PrintTypeToString();
strtype2 = targetType.PrintTypeToString();
throw LoreException.Create(Visitor.Location)
.Describe($"Unable to cast element of type '{strtype1}' to '{strtype2}':")
.Describe($"The element is too big for the target integer type.");
}
}
// Perform a float to signed integer cast if needed
else if (IsFloatOrDouble(elem))
{
elem = LLVM.BuildFPToSI(builder, elem, targetType, "tmpfptosicast");
}
// Unsupported element type
else
{
// Unable to perform a meaningful cast
strtype1 = elem.TypeOf().PrintTypeToString();
strtype2 = targetType.PrintTypeToString();
throw LoreException.Create(Visitor.Location).Describe($"Unable to cast element of type '{strtype1}' to '{strtype2}':");
}
// Perform an integer cast
return(LLVM.BuildIntCast(builder, elem, targetType, "tmpcast"));
case LLVMTypeKind.LLVMFloatTypeKind:
case LLVMTypeKind.LLVMDoubleTypeKind:
// Perform a signed integer to float cast if needed
if (IsInteger(elem))
{
elem = LLVM.BuildSIToFP(builder, elem, targetType, "tmpsitofpcast");
}
return(LLVM.BuildFPCast(builder, elem, targetType, "tmpfcast"));
}
// Unable to perform a meaningful cast
strtype1 = elem.TypeOf().PrintTypeToString();
strtype2 = targetType.PrintTypeToString();
throw LoreException.Create(Visitor.Location).Describe($"Unable to cast element of type '{strtype1}' to '{strtype2}':");
}
