ClickHouse/src/Functions/FunctionIfBase.h
2023-06-20 11:42:22 +03:00

84 lines
2.5 KiB
C++

#pragma once
#include <Functions/IFunction.h>
#include <DataTypes/Native.h>
#include <DataTypes/DataTypeNullable.h>
#include "config.h"
namespace DB
{
class FunctionIfBase : public IFunction
{
#if USE_EMBEDDED_COMPILER
public:
bool isCompilableImpl(const DataTypes & types, const DataTypePtr & result_type) const override
{
if (!canBeNativeType(result_type))
return false;
/// It's difficult to compare Date and DateTime - cannot use JIT compilation.
bool has_date = false;
bool has_datetime = false;
for (const auto & type : types)
{
auto type_removed_nullable = removeNullable(type);
WhichDataType which(type_removed_nullable);
if (which.isDate())
has_date = true;
if (which.isDateTime())
has_datetime = true;
if (has_date && has_datetime)
return false;
if (!canBeNativeType(type_removed_nullable))
return false;
}
return true;
}
llvm::Value * compileImpl(llvm::IRBuilderBase & builder, const ValuesWithType & arguments, const DataTypePtr & result_type) const override
{
auto & b = static_cast<llvm::IRBuilder<> &>(builder);
auto * head = b.GetInsertBlock();
auto * join = llvm::BasicBlock::Create(head->getContext(), "join_block", head->getParent());
std::vector<std::pair<llvm::BasicBlock *, llvm::Value *>> returns;
for (size_t i = 0; i + 1 < arguments.size(); i += 2)
{
auto * then = llvm::BasicBlock::Create(head->getContext(), "then_" + std::to_string(i), head->getParent());
auto * next = llvm::BasicBlock::Create(head->getContext(), "next_" + std::to_string(i), head->getParent());
const auto & cond = arguments[i];
b.CreateCondBr(nativeBoolCast(b, cond), then, next);
b.SetInsertPoint(then);
auto * value = nativeCast(b, arguments[i + 1], result_type);
returns.emplace_back(b.GetInsertBlock(), value);
b.CreateBr(join);
b.SetInsertPoint(next);
}
auto * else_value = nativeCast(b, arguments.back(), result_type);
returns.emplace_back(b.GetInsertBlock(), else_value);
b.CreateBr(join);
b.SetInsertPoint(join);
auto * phi = b.CreatePHI(toNativeType(b, result_type), static_cast<unsigned>(returns.size()));
for (const auto & [block, value] : returns)
phi->addIncoming(value, block);
return phi;
}
#endif
};
}