C++ Ada virtual-inheritance layout

/* { dg-do compile } */
/* { dg-require-effective-target lp64 } */
/* { dg-options "-fdump-ada-spec-slim" } */
/* { dg-final { scan-file virtual_inheritance_layout_c.ads "for Virtual'Size use 128;" } } */
/* { dg-final { scan-file virtual_inheritance_layout_c.ads "for Virtual'Object_Size use 128;" } } */
/* { dg-final { scan-file virtual_inheritance_layout_c.ads "for Virtual'Alignment use 8;" } } */
/* { dg-final { scan-file virtual_inheritance_layout_c.ads "derived_value at 8 range 0 .. 31;" } } */
/* { dg-final { scan-file virtual_inheritance_layout_c.ads "field_2 at 12 range 0 .. 31;" } } */

struct Root
{
  int root_value;
};

struct Virtual : virtual Root
{
  int derived_value;
  Virtual (int root, int derived);
};

Virtual::Virtual (int root, int derived)
  : Root {root}, derived_value {derived}
{}

extern "C" unsigned long cpp_root_size () { return sizeof (Root); }
extern "C" unsigned long cpp_virtual_size () { return sizeof (Virtual); }
extern "C" unsigned long cpp_virtual_alignment () { return alignof (Virtual); }
extern "C" unsigned long cpp_derived_offset ()
{
  Virtual object (0, 0);
  return reinterpret_cast<char *> (&object.derived_value)
    - reinterpret_cast<char *> (&object);
}
extern "C" unsigned long cpp_root_offset ()
{
  Virtual object (0, 0);
  return reinterpret_cast<char *> (&object.root_value)
    - reinterpret_cast<char *> (&object);
}
extern "C" Virtual *cpp_create (int root, int derived)
{
  return new Virtual (root, derived);
}
extern "C" void cpp_delete (Virtual *object) { delete object; }
extern "C" int cpp_root_value (const Virtual *object)
{
  return object->root_value;
}
extern "C" int cpp_derived_value (const Virtual *object)
{
  return object->derived_value;
}

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

with Ada.Text_IO;
with Interfaces.C; use Interfaces.C;
with System;
with Virtual_Inheritance_Layout_C;

procedure Virtual_Inheritance_Layout_Consumer is
   package Bindings renames Virtual_Inheritance_Layout_C;
   subtype Virtual is Bindings.Class_Virtual.Virtual;
   Object : access Virtual := Bindings.cpp_create (101, 202);

   function Bytes (Bits : Natural) return unsigned_long is
     (unsigned_long (Bits / System.Storage_Unit));

   Layout_Matches : constant Boolean :=
     Bytes (Virtual'Object_Size) = Bindings.cpp_virtual_size
     and then unsigned_long (Virtual'Alignment) =
       Bindings.cpp_virtual_alignment
     and then unsigned_long (Object.derived_value'Position) =
       Bindings.cpp_derived_offset
     and then unsigned_long (Object.field_2'Position) =
       Bindings.cpp_root_offset;
begin
   if Object = null
     or else Bytes (Bindings.Root'Object_Size) /= Bindings.cpp_root_size
     or else Bindings.cpp_root_value (Object) /= 101
     or else Bindings.cpp_derived_value (Object) /= 202
   then
      raise Program_Error with "C++ virtual object setup differs";
   end if;

   if Layout_Matches then
      Object.derived_value := 303;
      Object.field_2.root_value := 404;
      if Bindings.cpp_derived_value (Object) /= 303
        or else Bindings.cpp_root_value (Object) /= 404
      then
         raise Program_Error with "Ada writes use the wrong virtual layout";
      end if;
      Ada.Text_IO.Put_Line ("MATCH C++ Ada virtual inheritance");
   else
      Ada.Text_IO.Put_Line ("MISMATCH C++ Ada virtual inheritance");
   end if;

   Bindings.cpp_delete (Object);
end Virtual_Inheritance_Layout_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="$root/bundles/cxx-ada-virtual-inheritance-layout/tests/virtual-inheritance-layout.C"
ada_fixture="$root/bundles/cxx-ada-virtual-inheritance-layout/tests/virtual_inheritance_layout_consumer.adb"
work=$(mktemp -d "${TMPDIR:-/tmp}/gnat-cxx-ada-virtual-layout.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[@]}" "$gxx" -c "-O$optimization" \
      -fdump-ada-spec-slim virtual-inheritance-layout.C
    "${REGRESSION_ENV[@]}" "$REGRESSION_GNATMAKE" -q -f \
      "-O$optimization" virtual_inheritance_layout_consumer.adb \
      -largs virtual-inheritance-layout.o -lstdc++
    "${REGRESSION_ENV[@]}" ./virtual_inheritance_layout_consumer
  ) >"$case_dir/output.log" 2>&1 || {
    cat "$case_dir/output.log"
    exit 1
  }

  spec="$case_dir/virtual_inheritance_layout_c.ads"
  if [[ "$state" == unpatched ]]; then
    grep -Fx "MISMATCH C++ Ada virtual inheritance" "$case_dir/output.log"
    if grep -Fq "for Virtual'Object_Size use" "$spec"; then
      echo "error: unpatched mapper unexpectedly emitted virtual layout" >&2
      exit 1
    fi
    echo "cxx-ada-virtual-inheritance-layout -O$optimization: expected mismatch (GCC $version)"
    continue
  fi

  grep -F "for Virtual'Size use" "$spec"
  grep -F "for Virtual'Object_Size use" "$spec"
  grep -F "for Virtual'Alignment use" "$spec"
  grep -F "derived_value at" "$spec"
  grep -F "field_2 at" "$spec"
  grep -Fx "MATCH C++ Ada virtual inheritance" "$case_dir/output.log"
  echo "cxx-ada-virtual-inheritance-layout -O$optimization: patched (GCC $version)"
done