carbon-lang/toolchain/lower/handle_expression_category.cpp

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include "toolchain/lower/function_context.h"
#include "toolchain/sem_ir/file.h"

namespace Carbon::Lower {

auto HandleBindValue(FunctionContext& context, SemIR::InstId inst_id,
                     SemIR::BindValue inst) -> void {
  switch (auto rep =
              SemIR::GetValueRepresentation(context.sem_ir(), inst.type_id);
          rep.kind) {
    case SemIR::ValueRepresentation::Unknown:
      CARBON_FATAL()
          << "Value binding for type with incomplete value representation";
    case SemIR::ValueRepresentation::None:
      // Nothing should use this value, but StubReference needs a value to
      // propagate.
      // TODO: Remove this now the StubReferences are gone.
      context.SetLocal(inst_id,
                       llvm::PoisonValue::get(context.GetType(inst.type_id)));
      break;
    case SemIR::ValueRepresentation::Copy:
      context.SetLocal(inst_id, context.builder().CreateLoad(
                                    context.GetType(inst.type_id),
                                    context.GetValue(inst.value_id)));
      break;
    case SemIR::ValueRepresentation::Pointer:
      context.SetLocal(inst_id, context.GetValue(inst.value_id));
      break;
    case SemIR::ValueRepresentation::Custom:
      CARBON_FATAL() << "TODO: Add support for BindValue with custom value rep";
  }
}

auto HandleTemporary(FunctionContext& context, SemIR::InstId inst_id,
                     SemIR::Temporary inst) -> void {
  context.FinishInitialization(inst.type_id, inst.storage_id, inst.init_id);
  context.SetLocal(inst_id, context.GetValue(inst.storage_id));
}

auto HandleTemporaryStorage(FunctionContext& context, SemIR::InstId inst_id,
                            SemIR::TemporaryStorage inst) -> void {
  context.SetLocal(inst_id,
                   context.builder().CreateAlloca(context.GetType(inst.type_id),
                                                  nullptr, "temp"));
}

auto HandleValueAsReference(FunctionContext& context, SemIR::InstId inst_id,
                            SemIR::ValueAsReference inst) -> void {
  CARBON_CHECK(SemIR::GetExpressionCategory(context.sem_ir(), inst.value_id) ==
               SemIR::ExpressionCategory::Value);
  CARBON_CHECK(
      SemIR::GetValueRepresentation(context.sem_ir(), inst.type_id).kind ==
      SemIR::ValueRepresentation::Pointer);
  context.SetLocal(inst_id, context.GetValue(inst.value_id));
}

auto HandleValueOfInitializer(FunctionContext& context, SemIR::InstId inst_id,
                              SemIR::ValueOfInitializer inst) -> void {
  CARBON_CHECK(SemIR::GetExpressionCategory(context.sem_ir(), inst.init_id) ==
               SemIR::ExpressionCategory::Initializing);
  CARBON_CHECK(
      SemIR::GetValueRepresentation(context.sem_ir(), inst.type_id).kind ==
      SemIR::ValueRepresentation::Copy);
  CARBON_CHECK(
      SemIR::GetInitializingRepresentation(context.sem_ir(), inst.type_id)
          .kind == SemIR::InitializingRepresentation::ByCopy);
  context.SetLocal(inst_id, context.GetValue(inst.init_id));
}

}  // namespace Carbon::Lower