Files
mercury/tests/hard_coded/reuse_array.m
2020-10-03 17:47:12 +10:00

88 lines
2.4 KiB
Mathematica

%---------------------------------------------------------------------------%
% vim: ts=4 sw=4 et ft=mercury
%---------------------------------------------------------------------------%
% Test structure sharing annotations on array operations.
%---------------------------------------------------------------------------%
:- module reuse_array.
:- interface.
:- import_module io.
:- impure pred main(io::di, io::uo) is cc_multi.
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
:- implementation.
:- import_module array.
:- import_module list.
:- type struct
---> struct(int, f :: int).
%---------------------------------------------------------------------------%
main(!IO) :-
Struct1 = struct(1, dummy),
impure addr(Struct1, Addr1),
array.init(5, Struct1, Array0),
% Structure reuse requires a deconstruction which it can consider the death
% of a structure, so we oblige.
unused(Struct1 ^ f),
Struct2 = struct(2, dummy),
impure addr(Struct2, Addr2),
unused(Struct2 ^ f),
% Struct1 should NOT be reused here, as it shares with Array0.
% Struct2 can and should be reused instead.
Struct3 = struct(3, dummy),
impure addr(Struct3, Addr3),
array.unsafe_set(3, Struct3, Array0, Array),
unused(Struct3 ^ f),
% Struct3 should NOT be reused for Struct4, as it is shared with Array.
Struct4 = struct(4, dummy),
impure addr(Struct4, Addr4),
array.to_list(Array, List),
io.write(List, !IO),
io.nl(!IO),
list.sort_and_remove_dups([Addr1, Addr2, Addr3, Addr4], Addrs),
list.length(Addrs, NumAddrs),
( if
NumAddrs = 4
then
io.write_string("4 distinct addresses - no reuse detected\n", !IO)
else if
NumAddrs = 3,
Addr2 = Addr3
then
io.write_string("3 distinct addresses - reuse detected\n", !IO)
else
io.write_string("unexpected addresses: ", !IO),
io.write(Addrs, !IO),
io.nl(!IO)
).
:- impure pred addr(T::ui, int::uo) is cc_multi.
:- pragma foreign_proc("C",
addr(T::ui, Ptr::uo),
[will_not_call_mercury, thread_safe, no_sharing],
"
Ptr = (MR_Integer) T;
").
% This is used to force structures to be constructed dynamically.
:- func dummy = (int::uo).
:- pragma no_inline(dummy/0).
dummy = 999.
:- pred unused(int::unused) is det.
unused(_).