C++ Ada template nested types

/* { dg-do compile } */
/* { dg-options "-std=gnu++20 -fdump-ada-spec-slim" } */
/* { dg-final { scan-file template_nested_types_c.ads "package Buffer_int_4 is" } } */
/* { dg-final { scan-file template_nested_types_c.ads "package Defaults_int_2 is" } } */
/* { dg-final { scan-file template_nested_types_c.ads "type anon_array[0-9]+ is array \(0 \.\. 3\) of aliased int;" } } */
/* { dg-final { scan-file template_nested_types_c.ads "type anon_array[0-9]+ is array \(0 \.\. 1\) of aliased int;" } } */

template <typename T, unsigned N>
struct Buffer
{
  T values[N];
};

template struct Buffer<int, 4>;

template <typename T = int, unsigned N = 2>
struct Defaults
{
  T values[N];
};

template struct Defaults<>;

extern "C" int
buffer_sum (const Buffer<int, 4> *value)
{
  return value->values[0] + value->values[1]
    + value->values[2] + value->values[3];
}

extern "C" int
defaults_sum (const Defaults<> *value)
{
  return value->values[0] + value->values[1];
}

/* { dg-final { cleanup-ada-spec } } */

with Interfaces.C; use Interfaces.C;
with Template_Nested_Types_C;

procedure Template_Nested_Types_Consumer is
   package Bindings renames Template_Nested_Types_C;

   Buffer_Value : aliased Bindings.Buffer_Int_4.Buffer :=
     (values => (1, 2, 3, 4));
   Defaults_Value : aliased Bindings.Defaults_Int_2.Defaults :=
     (values => (5, 6));
begin
   if Bindings.buffer_sum (Buffer_Value'Access) /= 10
     or else Bindings.defaults_sum (Defaults_Value'Access) /= 11
   then
      raise Program_Error with "template array layout or binding is wrong";
   end if;
end Template_Nested_Types_Consumer;

#!/usr/bin/env bash
set -euo pipefail

if [[ $# -ne 3 ]]; then
  echo "usage: $0 TOOLCHAIN_ROOT GCC_VERSION unpatched|patched" >&2
  exit 2
fi

root=$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)
source "$root/scripts/regression-common.sh"
resolve_regression_toolchain "$1"
version=$2
state=$3
[[ "$state" == unpatched || "$state" == patched ]] || {
  echo "error: state must be unpatched or patched" >&2
  exit 2
}

gxx="$REGRESSION_TOOLCHAIN/bin/g++"
[[ -x "$gxx" ]] || {
  echo "error: no g++ in $REGRESSION_TOOLCHAIN" >&2
  exit 1
}

cxx_fixture="$root/bundles/cxx-ada-template-nested-types/tests/template-nested-types.C"
ada_fixture="$root/bundles/cxx-ada-template-nested-types/tests/template_nested_types_consumer.adb"
work=$(mktemp -d "${TMPDIR:-/tmp}/gnat-cxx-ada-template-nested.XXXXXX")
trap 'rm -rf "$work"' EXIT

for optimization in 0 2; do
  case_dir="$work/O$optimization"
  mkdir -p "$case_dir"
  cp "$cxx_fixture" "$ada_fixture" "$case_dir/"
  (
    cd "$case_dir"
    "${REGRESSION_ENV[@]}" "$gxx" -std=gnu++20 -c "-O$optimization" \
      -fdump-ada-spec-slim template-nested-types.C
  )

  spec="$case_dir/template_nested_types_c.ads"
  [[ -f "$spec" ]] || {
    echo "error: g++ did not generate $spec" >&2
    exit 1
  }

  set +e
  (
    cd "$case_dir"
    "${REGRESSION_ENV[@]}" "$REGRESSION_GNATMAKE" -q -f \
      "-O$optimization" template_nested_types_consumer.adb \
      -largs template-nested-types.o -lstdc++
    "${REGRESSION_ENV[@]}" ./template_nested_types_consumer
  ) >"$case_dir/run.log" 2>&1
  run_status=$?
  set -e

  if [[ "$state" == unpatched ]]; then
    [[ $run_status -ne 0 ]] || {
      echo "error: unpatched template nested-type regression unexpectedly passed" >&2
      exit 1
    }
    grep -Eiq 'anon_array.*undefined' "$case_dir/run.log" || {
      cat "$case_dir/run.log"
      exit 1
    }
    echo "cxx-ada-template-nested-types -O$optimization: expected missing type (GCC $version)"
    continue
  fi

  [[ $run_status -eq 0 ]] || {
    cat "$case_dir/run.log"
    exit 1
  }
  [[ $(grep -Ec 'type anon_array[0-9]+ is array' "$spec") -eq 2 ]] || {
    echo "error: expected two package-local anonymous array declarations" >&2
    exit 1
  }
  echo "cxx-ada-template-nested-types -O$optimization: patched (GCC $version)"
done