Ltac prove_call_setup1 subsumes :=
match goal with
| |- @semax _ _ _ (@exp _ _ _ _) _ _ =>
fail 1 "forward_call fails because your precondition starts with EX.
Use Intros to move the existentially bound variables above the line"
| |- @semax ?CS _ ?Delta (PROPx ?P (LOCALx ?Q (SEPx ?R))) ?c _ =>
lazymatch c with
| context [Scall _ (Evar ?id ?ty) ?bl] =>
let R' := strip1_later R in
exploit (call_setup1_i2 CS Delta P Q R' R id ty bl);
[check_prove_local2ptree
| apply can_assume_funcptr2;
[ check_function_name
| lookup_spec id
| find_spec_in_globals'
| simpl; reflexivity  (* function-id type in AST matches type in funspec *)
]
| apply subsumes
| auto 50 with derives
| simpl; reflexivity  (* function-id type in AST matches type in funspec *)
|check_typecheck
|check_typecheck
|check_cast_params
|reflexivity
| ..
]
| context [Scall _ ?a ?bl] =>
let R' := strip1_later R in
exploit (call_setup1_i CS Delta P Q R R' a bl);
[check_prove_local2ptree
|reflexivity
|prove_func_ptr
| apply subsumes
|auto 50 with derives
|check_parameter_types
|check_typecheck
|check_typecheck
|check_cast_params
|reflexivity
| ]
end
end.
Ltac prove_call_setup subsumes witness :=
prove_call_setup1 subsumes;
[ .. |
match goal with |- call_setup1 _ _ _ _ _ _ _ _ _ _ _ _ _ _ ?A _ _ _ _ _ _ _ -> _ =>
check_witness_type A witness
end;
let H := fresh in
intro H;
match goal with | |- @semax ?CS _ _ _ _ _ =>
let Frame := fresh "Frame" in evar (Frame: list mpred);
exploit (call_setup2_i _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ H witness Frame); clear H;
[ reflexivity
| check_prove_local2ptree
| Forall_pTree_from_elements
| unfold check_gvars_spec; solve [exact I | reflexivity]
| try change_compspecs CS; cancel_for_forward_call
|
]
end].
Ltac fwd_call' subsumes witness :=
lazymatch goal with
| |- semax _ _ (Ssequence (Scall _ _ _) _) _ =>
eapply semax_seq';
[prove_call_setup subsumes witness;
clear_Delta_specs; clear_MORE_POST;
[ .. |
lazymatch goal with
| |- _ -> semax _ _ (Scall (Some _) _ _) _ =>
forward_call_id1_wow
| |- call_setup2 _ _ _ _ _ _ _ _ _ _ _ _ ?retty _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ->
semax _ _ (Scall None _ _) _ =>
tryif (unify retty Tvoid)
then forward_call_id00_wow
else forward_call_id01_wow
end]
| after_forward_call ]
| |- semax _ _ (Ssequence (Ssequence (Scall (Some ?ret') _ _)
(Sset _ (Ecast (Etempvar ?ret'2 _) _))) _) _ =>
unify ret' ret'2;
eapply semax_seq';
[prove_call_setup subsumes witness;
clear_Delta_specs; clear_MORE_POST;
[ .. | forward_call_id1_x_wow ]
|  after_forward_call ]
| |- semax _ _ (Ssequence (Ssequence (Scall (Some ?ret') _ _)
(Sset _ (Etempvar ?ret'2 _))) _) _ =>
unify ret' ret'2;
eapply semax_seq';
[prove_call_setup subsumes witness;
clear_Delta_specs; clear_MORE_POST;
[ .. | forward_call_id1_y_wow ]
|  after_forward_call ]
| |- _ => rewrite <- seq_assoc; fwd_call' subsumes witness
end.
Ltac fwd_call subsumes witness :=
try lazymatch goal with
| |- semax _ _ (Scall _ _ _) _ => rewrite -> semax_seq_skip
end;
repeat lazymatch goal with
| |- semax _ _ (Ssequence (Ssequence (Ssequence _ _) _) _) _ =>
rewrite <- seq_assoc
end;
lazymatch goal with |- @semax ?CS _ ?Delta _ (Ssequence ?C _) _ =>
lazymatch C with context [Scall _ _ _] =>
fwd_call' subsumes witness
end
end.
Tactic Notation "forward_call" constr(witness) := fwd_call subsume_funspec_refl witness.
Tactic Notation "forward_call" constr(subsumes) constr(witness) := fwd_call subsumes witness.
Ltac tuple_evar2 name T cb evar_tac :=
lazymatch T with
| prod ?A ?B => tuple_evar2 name A
ltac: (fun xA =>
tuple_evar2 name B ltac: (fun xB =>
cb (xA, xB)) evar_tac) evar_tac
| _ => my_unshelve_evar name T cb evar_tac
end; idtac.
Ltac get_function_witness_type func :=
let TA := constr:(functors.MixVariantFunctor._functor
(rmaps.dependent_type_functor_rec nil func) mpred) in
let TA' := eval cbv
[functors.MixVariantFunctor._functor
functors.MixVariantFunctorGenerator.fpair
functors.MixVariantFunctorGenerator.fconst
functors.MixVariantFunctorGenerator.fidentity
rmaps.dependent_type_functor_rec
functors.GeneralFunctorGenerator.CovariantBiFunctor_MixVariantFunctor_compose
functors.CovariantFunctorGenerator.fconst
functors.CovariantFunctorGenerator.fidentity
functors.CovariantBiFunctor._functor
functors.CovariantBiFunctorGenerator.Fpair
functors.GeneralFunctorGenerator.CovariantFunctor_MixVariantFunctor
functors.CovariantFunctor._functor
functors.MixVariantFunctor.fmap
] in TA
in let TA'' := eval simpl in TA'
in TA''.
Ltac new_prove_call_setup :=
prove_call_setup1 subsume_funspec_refl;
[ .. |
match goal with |- call_setup1 _ _ _ _ _ _ _ _ _ _ _ _ _ _ ?A _ _ _ _ _ _ _ -> _ =>
let x := fresh "x" in tuple_evar2 x ltac:(get_function_witness_type A)
ltac:(fun witness =>
let H := fresh in
intro H;
match goal with | |- @semax ?CS _ _ _ _ _ =>
let Frame := fresh "Frame" in evar (Frame: list mpred);
exploit (call_setup2_i _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ H witness Frame); clear H;
[ reflexivity
| check_prove_local2ptree
| Forall_pTree_from_elements
| unfold check_gvars_spec; solve [exact I | reflexivity]
| try change_compspecs CS; cancel_for_forward_call
|
]
end)
ltac:(fun _ => try refine tt; fail "Failed to infer some parts of witness")
end].
Ltac new_fwd_call' :=
lazymatch goal with
| |- semax _ _ (Ssequence (Scall _ _ _) _) _ =>
eapply semax_seq';
[new_prove_call_setup;
clear_Delta_specs; clear_MORE_POST;
[ .. |
lazymatch goal with
| |- _ -> semax _ _ (Scall (Some _) _ _) _ =>
forward_call_id1_wow
| |- call_setup2 _ _ _ _ _ _ _ _ _ _ _ _ ?retty _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ->
semax _ _ (Scall None _ _) _ =>
tryif (unify retty Tvoid)
then forward_call_id00_wow
else forward_call_id01_wow
end]
| after_forward_call ]
| |- semax _ _ (Ssequence (Ssequence (Scall (Some ?ret') _ _)
(Sset _ (Ecast (Etempvar ?ret'2 _) _))) _) _ =>
unify ret' ret'2;
eapply semax_seq';
[new_prove_call_setup;
clear_Delta_specs; clear_MORE_POST;
[ .. | forward_call_id1_x_wow ]
|  after_forward_call ]
| |- semax _ _ (Ssequence (Ssequence (Scall (Some ?ret') _ _)
(Sset _ (Etempvar ?ret'2 _))) _) _ =>
unify ret' ret'2;
eapply semax_seq';
[new_prove_call_setup;
clear_Delta_specs; clear_MORE_POST;
[ .. | forward_call_id1_y_wow ]
|  after_forward_call ]
| |- _ => rewrite <- seq_assoc; new_fwd_call'
end.
Ltac new_fwd_call:=
try lazymatch goal with
| |- semax _ _ (Scall _ _ _) _ => rewrite -> semax_seq_skip
end;
repeat lazymatch goal with
| |- semax _ _ (Ssequence (Ssequence (Ssequence _ _) _) _) _ =>
rewrite <- seq_assoc
end;
lazymatch goal with |- @semax ?CS _ ?Delta _ (Ssequence ?C _) _ =>
lazymatch C with context [Scall _ _ _] =>
new_fwd_call'
end
end.
Tactic Notation "forward_call"  := new_fwd_call.

Lemma seq_assoc2:
forall (Espec: OracleKind) {cs: compspecs}  Delta P c1 c2 c3 c4 Q,
semax Delta P (Ssequence (Ssequence c1 c2) (Ssequence c3 c4)) Q ->
semax Delta P (Ssequence (Ssequence (Ssequence c1 c2) c3) c4) Q.