Method BuildIfElse

cpp/src/gandiva/function_ir_builder.cc:24–61

namespace gandiva {

llvm::Value* FunctionIRBuilder::BuildIfElse(llvm::Value* condition,
                                            llvm::Type* return_type,
                                            std::function<llvm::Value*()> then_func,
                                            std::function<llvm::Value*()> else_func) {
  llvm::IRBuilder<>* builder = ir_builder();
  llvm::Function* function = builder->GetInsertBlock()->getParent();
  DCHECK_NE(function, nullptr);

  // Create blocks for the then, else and merge cases.
  llvm::BasicBlock* then_bb = llvm::BasicBlock::Create(*context(), "then", function);
  llvm::BasicBlock* else_bb = llvm::BasicBlock::Create(*context(), "else", function);
  llvm::BasicBlock* merge_bb = llvm::BasicBlock::Create(*context(), "merge", function);

  builder->CreateCondBr(condition, then_bb, else_bb);

  // Emit the then block.
  builder->SetInsertPoint(then_bb);
  auto then_value = then_func();
  builder->CreateBr(merge_bb);

  // refresh then_bb for phi (could have changed due to code generation of then_value).
  then_bb = builder->GetInsertBlock();

  // Emit the else block.
  builder->SetInsertPoint(else_bb);
  auto else_value = else_func();
  builder->CreateBr(merge_bb);

  // refresh else_bb for phi (could have changed due to code generation of else_value).
  else_bb = builder->GetInsertBlock();

  // Emit the merge block.
  builder->SetInsertPoint(merge_bb);
  llvm::PHINode* result_value = builder->CreatePHI(return_type, 2, "res_value");
  result_value->addIncoming(then_value, then_bb);
  result_value->addIncoming(else_value, else_bb);
  return result_value;
}

llvm::Function* FunctionIRBuilder::BuildFunction(const std::string& function_name,
                                                 llvm::Type* return_type,