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mercury/compiler/middle_rec.m
Peter Ross ddd77f6f0e Get pragma foreign_type working for the C backend.
Estimated hours taken: 16
Branches: main

Get pragma foreign_type working for the C backend.

doc/reference_manual.texi:
    Document C pragma foreign_types.

compiler/prog_data.m:
    Add il_foreign_type and c_foreign_type which contain all the
    necessary data to output a foreign_type on the respective backends.
    Change foreign_language_type to refer to these new types.

compiler/prog_io_pragma.m:
    Handle the changes to foreign_language_type, and parse C
    foreign_type declarations.

compiler/hlds_data.m:
    Change the hlds_data__foreign_type type so that it records both the
    C and IL foreign types.  This will allow one to output both foreign
    type declarations when doing intermodule optimization.

compiler/make_hlds.m:
    Changes so that we store both the IL and C foreign types in
    hlds_data__foreign_type.
    Also add an error checking pass where we check that there is a
    foreign type for the back-end we are currently compiling to.

compiler/foreign.m:
    Change to_exported_type so that it works for both the C and IL
    backends by getting either the C or IL foreign_type definition.

compiler/llds.m:
compiler/pragma_c_gen.m:
    Change pragma_c_input and pragma_c_output so that they record
    whether or not a type is a foreign_type and if so what is the string
    which represents that foreign_type.

compiler/llds_out.m:
    When outputting pragma c_code variables that represent foreign_types
    get the casts correct.  Note that this adds the constraint on C
    foreign types that they are word sized, as all we are doing is
    casts, not boxing and unboxing.

compiler/mlds.m:
    Change mlds__foreign_type so that we store whether a type is an IL
    type or a C type.  It is the responsibility of the code generator
    that we never create a reference to a IL foreign type when on the C
    back-end, and vice versa.

compiler/mercury_to_mercury.m:
    Handle changes to prog_data__foreign_type.

compiler/hlds_out.m:
compiler/intermod.m:
compiler/magic_util.m:
compiler/ml_code_gen.m:
compiler/ml_type_gen.m:
compiler/recompilation_usage.m:
compiler/term_util.m:
compiler/type_ctor_info.m:
compiler/unify_proc.m:
    Handle changes to hlds_data__foreign_type.

compiler/exprn_aux.m:
compiler/livemap.m:
compiler/middle_rec.m:
compiler/opt_util.m:
    Handle changes to the pragma_c_input and pragma_c_output types.

compiler/ml_code_util.m:
compiler/mlds_to_gcc.m:
compiler/mlds_to_il.m:
compiler/mlds_to_java.m:
compiler/mlds_to_c.m:
    Handle changes to mlds__foreign_type.
2002-05-07 11:03:17 +00:00

587 lines
21 KiB
Mathematica

%---------------------------------------------------------------------------%
% Copyright (C) 1994-2002 The University of Melbourne.
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING in the Mercury distribution.
%---------------------------------------------------------------------------%
%
% Code generation - do middle recursion optimization
% Main authors: zs and conway.
%
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
:- module ll_backend__middle_rec.
:- interface.
:- import_module hlds__hlds_goal, ll_backend__llds, ll_backend__code_info.
:- pred middle_rec__match_and_generate(hlds_goal, code_tree,
code_info, code_info).
:- mode middle_rec__match_and_generate(in, out, in, out) is semidet.
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
:- implementation.
:- import_module parse_tree__prog_data, parse_tree__prog_out.
:- import_module hlds__hlds_module, hlds__hlds_data, hlds__goal_form.
:- import_module hlds__hlds_llds.
:- import_module ll_backend__code_gen, ll_backend__unify_gen.
:- import_module ll_backend__code_util, ll_backend__opt_util.
:- import_module ll_backend__code_aux.
:- import_module backend_libs__builtin_ops, backend_libs__code_model.
:- import_module libs__tree.
:- import_module bool, int, string, list, assoc_list, set, std_util.
:- import_module require.
%---------------------------------------------------------------------------%
middle_rec__match_and_generate(Goal, Instrs, CodeInfo0, CodeInfo) :-
Goal = GoalExpr - GoalInfo,
(
GoalExpr = switch(Var, cannot_fail, [Case1, Case2]),
Case1 = case(ConsId1, Goal1),
Case2 = case(ConsId2, Goal2),
(
contains_only_builtins(Goal1),
code_aux__contains_simple_recursive_call(Goal2,
CodeInfo0, _)
->
middle_rec__generate_switch(Var, ConsId1, Goal1, Goal2,
GoalInfo, Instrs, CodeInfo0, CodeInfo)
;
contains_only_builtins(Goal2),
code_aux__contains_simple_recursive_call(Goal1,
CodeInfo0, _)
->
middle_rec__generate_switch(Var, ConsId2, Goal2, Goal1,
GoalInfo, Instrs, CodeInfo0, CodeInfo)
;
fail
)
;
GoalExpr = if_then_else(Vars, Cond, Then, Else),
(
contains_only_builtins(Cond),
contains_only_builtins(Then),
code_aux__contains_simple_recursive_call(Else,
CodeInfo0, no)
->
semidet_fail,
middle_rec__generate_ite(Vars, Cond, Then, Else,
in_else, GoalInfo, Instrs,
CodeInfo0, CodeInfo)
;
contains_only_builtins(Cond),
code_aux__contains_simple_recursive_call(Then,
CodeInfo0, no),
contains_only_builtins(Else)
->
semidet_fail,
middle_rec__generate_ite(Vars, Cond, Then, Else,
in_then, GoalInfo, Instrs,
CodeInfo0, CodeInfo)
;
fail
)
).
:- type ite_rec ---> in_then ; in_else.
%---------------------------------------------------------------------------%
:- pred middle_rec__generate_ite(list(prog_var), hlds_goal, hlds_goal,
hlds_goal, ite_rec, hlds_goal_info,
code_tree, code_info, code_info).
:- mode middle_rec__generate_ite(in, in, in, in, in, in, out, in, out)
is det.
middle_rec__generate_ite(_Vars, _Cond, _Then, _Else, _Rec, _IteGoalInfo,
Instrs) -->
( { semidet_fail } ->
{ Instrs = empty }
;
{ error("middle_rec__generate_ite reached") }
).
%---------------------------------------------------------------------------%
:- pred middle_rec__generate_switch(prog_var, cons_id, hlds_goal, hlds_goal,
hlds_goal_info, code_tree, code_info, code_info).
:- mode middle_rec__generate_switch(in, in, in, in, in, out, in, out)
is semidet.
middle_rec__generate_switch(Var, BaseConsId, Base, Recursive, SwitchGoalInfo,
Instrs) -->
code_info__get_stack_slots(StackSlots),
code_info__get_varset(VarSet),
{ code_aux__explain_stack_slots(StackSlots, VarSet, SlotsComment) },
code_info__get_module_info(ModuleInfo),
code_info__get_pred_id(PredId),
code_info__get_proc_id(ProcId),
{ code_util__make_local_entry_label(ModuleInfo, PredId, ProcId, no,
EntryLabel) },
code_info__pre_goal_update(SwitchGoalInfo, no),
unify_gen__generate_tag_test(Var, BaseConsId, branch_on_success,
BaseLabel, EntryTestCode),
{ tree__flatten(EntryTestCode, EntryTestListList) },
{ list__condense(EntryTestListList, EntryTestList) },
{ goal_info_get_store_map(SwitchGoalInfo, StoreMap) },
code_info__remember_position(BranchStart),
code_gen__generate_goal(model_det, Base, BaseGoalCode),
code_info__generate_branch_end(StoreMap, no, MaybeEnd1,
BaseSaveCode),
code_info__reset_to_position(BranchStart),
code_gen__generate_goal(model_det, Recursive, RecGoalCode),
code_info__generate_branch_end(StoreMap, MaybeEnd1, MaybeEnd,
RecSaveCode),
code_info__post_goal_update(SwitchGoalInfo),
code_info__after_all_branches(StoreMap, MaybeEnd),
code_info__get_arginfo(ArgModes),
code_info__get_headvars(HeadVars),
{ assoc_list__from_corresponding_lists(HeadVars, ArgModes, Args) },
code_info__setup_return(Args, LiveArgs, EpilogCode),
{ BaseCode = tree(BaseGoalCode, tree(BaseSaveCode, EpilogCode)) },
{ RecCode = tree(RecGoalCode, tree(RecSaveCode, EpilogCode)) },
{ LiveValCode = [livevals(LiveArgs) - ""] },
{ tree__flatten(BaseCode, BaseListList) },
{ list__condense(BaseListList, BaseList) },
{ tree__flatten(RecCode, RecListList) },
{ list__condense(RecListList, RecList) },
% In the code we generate, the base instruction sequence is executed
% in situations where this procedure has no stack frame. If this
% sequence refers to stackvars, it will be to some other procedure's
% variables, which is obviously incorrect.
{ opt_util__block_refers_stackvars(BaseList, no) },
{ list__append(BaseList, RecList, AvoidList) },
{ middle_rec__find_unused_register(AvoidList, AuxReg) },
{ middle_rec__split_rec_code(RecList, BeforeList0, AfterList) },
{ middle_rec__add_counter_to_livevals(BeforeList0, AuxReg,
BeforeList) },
code_info__get_next_label(Loop1Label),
code_info__get_next_label(Loop2Label),
code_info__get_total_stackslot_count(FrameSize),
{ middle_rec__generate_downloop_test(EntryTestList,
Loop1Label, Loop1Test) },
{ FrameSize = 0 ->
MaybeIncrSp = [],
MaybeDecrSp = [],
InitAuxReg = [assign(AuxReg, const(int_const(0)))
- "initialize counter register"],
IncrAuxReg = [assign(AuxReg, binop((+),
lval(AuxReg),
const(int_const(1))))
- "increment loop counter"],
DecrAuxReg = [assign(AuxReg, binop((-),
lval(AuxReg),
const(int_const(1))))
- "decrement loop counter"],
TestAuxReg = [if_val(binop((>),
lval(AuxReg), const(int_const(0))),
label(Loop2Label))
- "test on upward loop"]
;
PushMsg = code_gen__push_msg(ModuleInfo, PredId, ProcId),
MaybeIncrSp = [incr_sp(FrameSize, PushMsg) - ""],
MaybeDecrSp = [decr_sp(FrameSize) - ""],
InitAuxReg = [assign(AuxReg, lval(sp))
- "initialize counter register"],
IncrAuxReg = [],
DecrAuxReg = [],
TestAuxReg = [if_val(binop((>),
lval(sp), lval(AuxReg)),
label(Loop2Label))
- "test on upward loop"]
},
% Even though the recursive call is followed by some goals
% in the HLDS, these goals may generate no LLDS code, so
% it is in fact possible for AfterList to be empty.
% There is no point in testing BeforeList for empty,
% since if it is, the code is an infinite loop anyway.
{ AfterList = [] ->
list__condense([
[
label(EntryLabel) - "Procedure entry point",
comment(SlotsComment) - ""
],
EntryTestList,
[
label(Loop1Label)
- "start of the down loop"
],
BeforeList,
Loop1Test,
[
label(BaseLabel)
- "start of base case"
],
BaseList,
LiveValCode,
[
goto(succip)
- "exit from base case"
]
], InstrList)
;
% The instruction list we are constructing has two copies
% of BaseList. If this list of instructions defines any
% labels, we must either not apply this version of the
% optimization, or we must consistently substitute the
% labels (which will be referred to only from within the
% BaseList instructions themselves). We choose the former
% course.
middle_rec__find_labels(BaseList, BaseLabels),
BaseLabels = [],
list__condense([
[
label(EntryLabel) - "Procedure entry point",
comment(SlotsComment) - ""
],
EntryTestList,
InitAuxReg,
[
label(Loop1Label)
- "start of the down loop"
],
MaybeIncrSp,
IncrAuxReg,
BeforeList,
Loop1Test,
BaseList,
[
label(Loop2Label) - ""
],
AfterList,
MaybeDecrSp,
DecrAuxReg,
TestAuxReg,
LiveValCode,
[
goto(succip)
- "exit from recursive case",
label(BaseLabel)
- "start of base case"
],
BaseList,
LiveValCode,
[
goto(succip)
- "exit from base case"
]
], InstrList)
},
{ Instrs = node(InstrList) }.
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
:- pred middle_rec__generate_downloop_test(list(instruction), label,
list(instruction)).
:- mode middle_rec__generate_downloop_test(in, in, out) is det.
middle_rec__generate_downloop_test([], _, _) :-
error("middle_rec__generate_downloop_test on empty list").
middle_rec__generate_downloop_test([Instr0 | Instrs0], Target, Instrs) :-
( Instr0 = if_val(Test, _OldTarget) - _Comment ->
( Instrs0 = [] ->
true
;
error("middle_rec__generate_downloop_test: if_val followed by other instructions")
),
code_util__neg_rval(Test, NewTest),
Instrs = [if_val(NewTest, label(Target)) - "test on downward loop"]
;
middle_rec__generate_downloop_test(Instrs0, Target, Instrs1),
Instrs = [Instr0 | Instrs1]
).
%---------------------------------------------------------------------------%
:- pred middle_rec__split_rec_code(list(instruction),
list(instruction), list(instruction)).
:- mode middle_rec__split_rec_code(in, out, out) is det.
middle_rec__split_rec_code([], _, _) :-
error("did not find call in middle_rec__split_rec_code").
middle_rec__split_rec_code([Instr0 | Instrs1], Before, After) :-
( Instr0 = call(_, _, _, _, _, _) - _ ->
(
opt_util__skip_comments(Instrs1, Instrs2),
Instrs2 = [Instr2 | Instrs3],
Instr2 = label(_) - _
->
Before = [],
After = Instrs3
;
error("call not followed by label in middle_rec__split_rec_code")
)
;
middle_rec__split_rec_code(Instrs1, Before1, After),
Before = [Instr0 | Before1]
).
%---------------------------------------------------------------------------%
:- pred middle_rec__add_counter_to_livevals(list(instruction), lval,
list(instruction)).
:- mode middle_rec__add_counter_to_livevals(in, in, out) is det.
middle_rec__add_counter_to_livevals([], _Lval, []).
middle_rec__add_counter_to_livevals([I0|Is0], Lval, [I|Is]) :-
(
I0 = livevals(Lives0) - Comment
->
set__insert(Lives0, Lval, Lives),
I = livevals(Lives) - Comment
;
I = I0
),
middle_rec__add_counter_to_livevals(Is0, Lval, Is).
%---------------------------------------------------------------------------%
:- pred middle_rec__find_unused_register(list(instruction), lval).
:- mode middle_rec__find_unused_register(in, out) is det.
middle_rec__find_unused_register(Instrs, UnusedReg) :-
set__init(Used0),
middle_rec__find_used_registers(Instrs, Used0, Used1),
set__to_sorted_list(Used1, UsedList),
middle_rec__find_unused_register_2(UsedList, 1, UnusedReg).
:- pred middle_rec__find_unused_register_2(list(int), int, lval).
:- mode middle_rec__find_unused_register_2(in, in, out) is det.
middle_rec__find_unused_register_2([], N, reg(r, N)).
middle_rec__find_unused_register_2([H | T], N, Reg) :-
( N < H ->
Reg = reg(r, N)
;
N1 is N + 1,
middle_rec__find_unused_register_2(T, N1, Reg)
).
:- pred middle_rec__find_used_registers(list(instruction), set(int), set(int)).
:- mode middle_rec__find_used_registers(in, di, uo) is det.
middle_rec__find_used_registers([], Used, Used).
middle_rec__find_used_registers([Instr - _ | Instrs], Used0, Used) :-
middle_rec__find_used_registers_instr(Instr, Used0, Used1),
middle_rec__find_used_registers(Instrs, Used1, Used).
:- pred middle_rec__find_used_registers_instr(instr, set(int), set(int)).
:- mode middle_rec__find_used_registers_instr(in, di, uo) is det.
middle_rec__find_used_registers_instr(comment(_), Used, Used).
middle_rec__find_used_registers_instr(livevals(LvalSet), Used0, Used) :-
set__to_sorted_list(LvalSet, LvalList),
middle_rec__find_used_registers_lvals(LvalList, Used0, Used).
middle_rec__find_used_registers_instr(block(_, _, Instrs), Used0, Used) :-
middle_rec__find_used_registers(Instrs, Used0, Used).
middle_rec__find_used_registers_instr(assign(Lval, Rval), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used1),
middle_rec__find_used_registers_rval(Rval, Used1, Used).
middle_rec__find_used_registers_instr(call(_, _, _, _, _, _), Used, Used).
middle_rec__find_used_registers_instr(mkframe(_, _), Used, Used).
middle_rec__find_used_registers_instr(label(_), Used, Used).
middle_rec__find_used_registers_instr(goto(_), Used, Used).
middle_rec__find_used_registers_instr(computed_goto(Rval, _), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
middle_rec__find_used_registers_instr(c_code(_, _), Used, Used).
middle_rec__find_used_registers_instr(if_val(Rval, _), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
middle_rec__find_used_registers_instr(incr_hp(Lval, _, Rval, _), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used1),
middle_rec__find_used_registers_rval(Rval, Used1, Used).
middle_rec__find_used_registers_instr(mark_hp(Lval), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used).
middle_rec__find_used_registers_instr(restore_hp(Rval), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
middle_rec__find_used_registers_instr(free_heap(Rval), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
middle_rec__find_used_registers_instr(store_ticket(Lval), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used).
middle_rec__find_used_registers_instr(reset_ticket(Rval, _Rsn), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
middle_rec__find_used_registers_instr(discard_ticket, Used, Used).
middle_rec__find_used_registers_instr(prune_ticket, Used, Used).
middle_rec__find_used_registers_instr(mark_ticket_stack(Lval), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used).
middle_rec__find_used_registers_instr(prune_tickets_to(Rval), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
middle_rec__find_used_registers_instr(incr_sp(_, _), Used, Used).
middle_rec__find_used_registers_instr(decr_sp(_), Used, Used).
middle_rec__find_used_registers_instr(pragma_c(_, Components,
_, _, _, _, _, _), Used0, Used) :-
middle_rec__find_used_registers_components(Components, Used0, Used).
middle_rec__find_used_registers_instr(init_sync_term(Lval, _), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used).
middle_rec__find_used_registers_instr(fork(_, _, _), Used, Used).
middle_rec__find_used_registers_instr(join_and_terminate(Lval), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used).
middle_rec__find_used_registers_instr(join_and_continue(Lval,_), Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used).
:- pred middle_rec__find_used_registers_components(list(pragma_c_component),
set(int), set(int)).
:- mode middle_rec__find_used_registers_components(in, di, uo) is det.
middle_rec__find_used_registers_components([], Used, Used).
middle_rec__find_used_registers_components([Comp | Comps], Used0, Used) :-
middle_rec__find_used_registers_component(Comp, Used0, Used1),
middle_rec__find_used_registers_components(Comps, Used1, Used).
:- pred middle_rec__find_used_registers_component(pragma_c_component,
set(int), set(int)).
:- mode middle_rec__find_used_registers_component(in, di, uo) is det.
middle_rec__find_used_registers_component(pragma_c_inputs(In), Used0, Used) :-
insert_pragma_c_input_registers(In, Used0, Used).
middle_rec__find_used_registers_component(pragma_c_outputs(Out), Used0, Used) :-
insert_pragma_c_output_registers(Out, Used0, Used).
middle_rec__find_used_registers_component(pragma_c_user_code(_, _), Used, Used).
middle_rec__find_used_registers_component(pragma_c_raw_code(_, _), Used, Used).
middle_rec__find_used_registers_component(pragma_c_fail_to(_), Used, Used).
middle_rec__find_used_registers_component(pragma_c_noop, Used, Used).
:- pred middle_rec__find_used_registers_lvals(list(lval), set(int), set(int)).
:- mode middle_rec__find_used_registers_lvals(in, di, uo) is det.
middle_rec__find_used_registers_lvals([], Used, Used).
middle_rec__find_used_registers_lvals([Lval | Lvals], Used0, Used) :-
middle_rec__find_used_registers_lval(Lval, Used0, Used1),
middle_rec__find_used_registers_lvals(Lvals, Used1, Used).
:- pred middle_rec__find_used_registers_lval(lval, set(int), set(int)).
:- mode middle_rec__find_used_registers_lval(in, di, uo) is det.
middle_rec__find_used_registers_lval(Lval, Used0, Used) :-
( Lval = reg(r, N) ->
copy(N, N1),
set__insert(Used0, N1, Used)
; Lval = field(_, Rval, FieldNum) ->
middle_rec__find_used_registers_rval(Rval, Used0, Used1),
middle_rec__find_used_registers_rval(FieldNum, Used1, Used)
; Lval = lvar(_) ->
error("lvar found in middle_rec__find_used_registers_lval")
;
Used = Used0
).
:- pred middle_rec__find_used_registers_rval(rval, set(int), set(int)).
:- mode middle_rec__find_used_registers_rval(in, di, uo) is det.
middle_rec__find_used_registers_rval(Rval, Used0, Used) :-
(
Rval = lval(Lval),
middle_rec__find_used_registers_lval(Lval, Used0, Used)
;
Rval = var(_),
error("var found in middle_rec__find_used_registers_rval")
;
Rval = create(_, MaybeRvals, _, _, _, _, Reuse),
middle_rec__find_used_registers_maybe_rvals(
[Reuse | MaybeRvals], Used0, Used)
;
Rval = mkword(_, Rval1),
middle_rec__find_used_registers_rval(Rval1, Used0, Used)
;
Rval = const(_),
Used = Used0
;
Rval = unop(_, Rval1),
middle_rec__find_used_registers_rval(Rval1, Used0, Used)
;
Rval = binop(_, Rval1, Rval2),
middle_rec__find_used_registers_rval(Rval1, Used0, Used1),
middle_rec__find_used_registers_rval(Rval2, Used1, Used)
;
Rval = mem_addr(MemRef),
middle_rec__find_used_registers_mem_ref(MemRef, Used0, Used)
).
:- pred middle_rec__find_used_registers_mem_ref(mem_ref, set(int), set(int)).
:- mode middle_rec__find_used_registers_mem_ref(in, di, uo) is det.
middle_rec__find_used_registers_mem_ref(stackvar_ref(_), Used, Used).
middle_rec__find_used_registers_mem_ref(framevar_ref(_), Used, Used).
middle_rec__find_used_registers_mem_ref(heap_ref(Rval, _, _), Used0, Used) :-
middle_rec__find_used_registers_rval(Rval, Used0, Used).
:- pred middle_rec__find_used_registers_maybe_rvals(list(maybe(rval)),
set(int), set(int)).
:- mode middle_rec__find_used_registers_maybe_rvals(in, di, uo) is det.
middle_rec__find_used_registers_maybe_rvals([], Used, Used).
middle_rec__find_used_registers_maybe_rvals([MaybeRval | MaybeRvals],
Used0, Used) :-
(
MaybeRval = no,
Used1 = Used0
;
MaybeRval = yes(Rval),
middle_rec__find_used_registers_rval(Rval, Used0, Used1)
),
middle_rec__find_used_registers_maybe_rvals(MaybeRvals, Used1, Used).
:- pred insert_pragma_c_input_registers(list(pragma_c_input),
set(int), set(int)).
:- mode insert_pragma_c_input_registers(in, di, uo) is det.
insert_pragma_c_input_registers([], Used, Used).
insert_pragma_c_input_registers([Input|Inputs], Used0, Used) :-
Input = pragma_c_input(_, _, Rval, _),
middle_rec__find_used_registers_rval(Rval, Used0, Used1),
insert_pragma_c_input_registers(Inputs, Used1, Used).
:- pred insert_pragma_c_output_registers(list(pragma_c_output),
set(int), set(int)).
:- mode insert_pragma_c_output_registers(in, di, uo) is det.
insert_pragma_c_output_registers([], Used, Used).
insert_pragma_c_output_registers([Output|Outputs], Used0, Used) :-
Output = pragma_c_output(Lval, _, _, _),
middle_rec__find_used_registers_lval(Lval, Used0, Used1),
insert_pragma_c_output_registers(Outputs, Used1, Used).
%---------------------------------------------------------------------------%
% Find all the labels defined in an instruction sequence.
:- pred middle_rec__find_labels(list(instruction), list(label)).
:- mode middle_rec__find_labels(in, out) is det.
middle_rec__find_labels(Instrs, Label2) :-
middle_rec__find_labels_2(Instrs, [], Label2).
:- pred middle_rec__find_labels_2(list(instruction), list(label), list(label)).
:- mode middle_rec__find_labels_2(in, in, out) is det.
middle_rec__find_labels_2([], Labels, Labels).
middle_rec__find_labels_2([Instr - _ | Instrs], Labels0, Labels) :-
( Instr = label(Label) ->
Labels1 = [Label | Labels0]
; Instr = block(_, _, Block) ->
middle_rec__find_labels_2(Block, Labels0, Labels1)
;
Labels1 = Labels0
),
middle_rec__find_labels_2(Instrs, Labels1, Labels).