[fir] Add fir.embox conversion

Convert a `fir.embox` operation to LLVM IR dialect.
A `fir.embox` is converted to a sequence of operation that
create, allocate if needed, and populate a descriptor.

Current limitiation: alignment is set by default but should be retrieved in the specific target.

This patch is part of the upstreaming effort from fir-dev branch.

Reviewed By: kiranchandramohan, awarzynski

Differential Revision: https://reviews.llvm.org/D113756

Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: Jean Perier <jperier@nvidia.com>

flang/include/flang/Optimizer/Dialect/FIRTypes.td

@@ -317,6 +317,8 @@ def fir_RecordType : FIR_Type<"Record", "type"> {
 
     void finalize(llvm::ArrayRef<TypePair> lenPList,
                   llvm::ArrayRef<TypePair> typeList);
+
+    std::string getLoweredName() const;
 
     detail::RecordTypeStorage const *uniqueKey() const;
   }];

flang/include/flang/Optimizer/Support/TypeCode.h

@@ -0,0 +1,90 @@
+//===-- Optimizer/Support/TypeCode.h ----------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_SUPPORT_TYPECODE_H
+#define FORTRAN_OPTIMIZER_SUPPORT_TYPECODE_H
+
+#include "flang/ISO_Fortran_binding.h"
+#include "llvm/Support/ErrorHandling.h"
+
+namespace fir {
+
+//===----------------------------------------------------------------------===//
+// Translations of category and bitwidths to the type codes defined in flang's
+// ISO_Fortran_binding.h.
+//===----------------------------------------------------------------------===//
+
+inline int characterBitsToTypeCode(unsigned bitwidth) {
+  // clang-format off
+  switch (bitwidth) {
+  case 8:  return CFI_type_char;
+  case 16: return CFI_type_char16_t;
+  case 32: return CFI_type_char32_t;
+  default: llvm_unreachable("unsupported character size");
+  }
+  // clang-format on
+}
+
+inline int complexBitsToTypeCode(unsigned bitwidth) {
+  // clang-format off
+  switch (bitwidth) {
+  case 32:  return CFI_type_float_Complex;
+  case 64:  return CFI_type_double_Complex;
+  case 80:
+  case 128: return CFI_type_long_double_Complex;
+  default:  llvm_unreachable("unsupported complex size");
+  }
+  // clang-format on
+}
+
+inline int integerBitsToTypeCode(unsigned bitwidth) {
+  // clang-format off
+  switch (bitwidth) {
+  case 8:   return CFI_type_int8_t;
+  case 16:  return CFI_type_int16_t;
+  case 32:  return CFI_type_int32_t;
+  case 64:  return CFI_type_int64_t;
+  case 128: return CFI_type_int128_t;
+  default:  llvm_unreachable("unsupported integer size");
+  }
+  // clang-format on
+}
+
+inline int logicalBitsToTypeCode(unsigned bitwidth) {
+  // clang-format off
+  switch (bitwidth) {
+  case 8: return CFI_type_Bool;
+  case 16: return CFI_type_int_least16_t;
+  case 32: return CFI_type_int_least32_t;
+  case 64: return CFI_type_int_least64_t;
+  default: llvm_unreachable("unsupported logical size");
+  }
+  // clang-format on
+}
+
+inline int realBitsToTypeCode(unsigned bitwidth) {
+  // clang-format off
+  switch (bitwidth) {
+  case 32:  return CFI_type_float;
+  case 64:  return CFI_type_double;
+  case 80:
+  case 128: return CFI_type_long_double;
+  default:  llvm_unreachable("unsupported real size");
+  }
+  // clang-format on
+}
+
+static constexpr int derivedToTypeCode() { return CFI_type_struct; }
+
+} // namespace fir
+
+#endif // FORTRAN_OPTIMIZER_SUPPORT_TYPECODE_H