Files
mercury/deep_profiler/recursion_patterns.m
Zoltan Somogyi 62ec97d443 Report imports shadowed by other imports.
If a module has two or more import_module or use_module declarations
for the same module, (typically, but not always, one being in its interface
and one in its implementation), generate an informational message about
each redundant declaration if --warn-unused-imports is enabled.

compiler/hlds_module.m:
    We used to record the set of imported/used modules, and the set of
    modules imported/used in the interface of the current module. However,
    these sets

    - did not record the distinction between imports and uses;
    - did not allow distinction between single and multiple imports/uses;
    - did not record the locations of the imports/uses.

    The first distinction was needed only by module_qual.m, which *did*
    pay attention to it; the other two were not needed at all.

    To generate messages for imports/uses shadowing other imports/uses,
    we need all three, so change the data structure storing such information
    for *direct* imports to one that records all three of the above kinds
    of information. (For imports made by read-in interface and optimization
    files, the old set of modules approach is fine, and this diff leaves
    the set of thus *indirectly* imported module names alone.)

compiler/unused_imports.m:
    Use the extra information now available to generate a
    severity_informational message about any import or use that is made
    redundant by an earlier, more general import or use.

    Fix two bugs in the code that generated warnings for just plain unused
    modules.

    (1) It did not consider that a use of the builtin type char justified
    an import of char.m, but without that import, the type is not visible.

    (2) It scanned cons_ids in goals in procedure bodies, but did not scan
    cons_ids that have been put into the const_struct_db. (I did not update
    the code here when I added the const_struct_db.)

    Also, add a (hopefully temporary) workaround for a bug in
    make_hlds_passes.m, which is noted below.

    However, there are at least three problems that prevent us from enabling
    --warn-unused-imports by default.

    (1) In some places, the import of a module is used only by clauses for
    a predicate that also has foreign procs. When compiled in a grade that
    selects one of those foreign_procs as the implementation of the predicate,
    the clauses are discarded *without* being added to the HLDS at all.
    This leads unused_imports.m to generate an uncalled-for warning in such
    cases. To fix this, we would need to preserve the Mercury clauses for
    *all* predicates, even those with foreign procs, and do all the semantic
    checks on them before throwing them away. (I tried to do this once, and
    failed, but the task should be easier after the item list change.)

    (2) We have two pieces of code to generate import warnings. The one in
    unused_imports.m operates on the HLDS after type and mode checking,
    while module_qual.m operates on the parse tree before the creation of
    the HLDS. The former is more powerful, since it knows e.g. what types and
    modes are used in the bodies of predicates, and hence can generate warnings
    about an import being unused *anywhere* in a module, as opposed to just
    unused in its interface.

    If --warn-unused-imports is enabled, we will get two separate set of
    reports about an interface import being unused in the interface,
    *unless* we get a type or mode error, in which case unused_imports.m
    won't be invoked. But in case we do get such errors, we don't want to
    throw away the warnings from module_qual.m. We could store them and
    throw them away only after we know we won't need them, or just get
    the two modules to generate identical error_specs for each warning,
    so that the sort_and_remove_dups of the error specs will do the
    throwing away for us for free, if we get that far.

    (3) The valid/bug100.m test case was added as a regression test for a bug
    that was fixed in module_qual.m. However the bug is still present in
    unused_imports.m.

compiler/make_hlds_passes.m:
    Give hlds_module.m the extra information it now needs for each item_avail.

    Add an XXX for a bug that cannot be fixed right now: the setting of
    the status of abstract instances to abstract_imported. (The "abstract"
    part is correct; the "imported" part may not be.)

compiler/intermod.m:
compiler/try_expand.m:
compiler/xml_documentation.m:
    Conform to the change in hlds_module.m.

compiler/module_qual.m:
    Update the documentation of the relationship of this module
    with unused_imports.m.

compiler/hlds_data.m:
    Document a problem with the status of instance definitions.

compiler/hlds_out_module.m:
    Update the code that prints out the module_info to conform to the change
    to hlds_module.m.

    Print status information about instances, which was needed to diagnose
    one of the bugs in unused_imports.m. Format the output for instances
    nicer.

compiler/prog_item.m:
    Add a convenience predicate.

compiler/prog_data.m:
    Remove a type synonym that makes things harder to understand, not easier.

compiler/modules.m:
    Delete an XXX that asks for the feature this diff implements.
    Add another XXX about how that feature could be improved.

compiler/Mercury.options.m:
    Add some more modules to the list of modules on which the compiler
    should be invoked with --no-warn-unused-imports.

compiler/*.m:
library/*.m:
mdbcomp/*.m:
browser/*.m:
deep_profiler/*.m:
mfilterjavac/*.m:
    Delete unneeded imports. Many of these shadow other imports, and some
    are just plain unneeded, as shown by --warn-unused-imports. In a few
    modules, there were a *lot* of unneeded imports, but most had just
    one or two.

    In a few cases, removing an import from a module, because it *itself*
    does not need it, required adding that same import to those of its
    submodules which *do* need it.

    In a few cases, conform to other changes above.

tests/invalid/Mercury.options:
    Test the generation of messages about import shadowing on the existing
    import_in_parent.m test case (although it was also tested very thoroughly
    when giving me the information needed for the deletion of all the
    unneeded imports above).

tests/*/*.{m,*exp}:
    Delete unneeded imports, and update any expected error messages
    to expect the now-smaller line numbers.
2015-08-25 00:38:49 +10:00

1030 lines
40 KiB
Mathematica

%-----------------------------------------------------------------------------%
% vim: ft=mercury ts=4 sw=4 et
%-----------------------------------------------------------------------------%
% Copyright (C) 2010-2011 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.
%-----------------------------------------------------------------------------%
%
% File: recursion_patterns.m.
% Authors: pbone.
%
% This module contains code that analysis the recursive structures of cliques.
% It is intended for use on the automatic parallelisation analysis.
%
%----------------------------------------------------------------------------%
:- module recursion_patterns.
:- interface.
:- import_module report.
:- import_module measurements.
:- import_module profile.
:- import_module maybe.
%----------------------------------------------------------------------------%
:- pred create_clique_recursion_costs_report(deep::in, clique_ptr::in,
maybe_error(clique_recursion_report)::out) is det.
:- pred create_recursion_types_frequency_report(deep::in,
maybe_error(recursion_types_frequency_report)::out) is det.
%----------------------------------------------------------------------------%
:- pred recursion_type_get_maybe_avg_max_depth(recursion_type,
maybe(recursion_depth)).
:- mode recursion_type_get_maybe_avg_max_depth(in(recursion_type_known_costs),
out(maybe_yes(ground))) is det.
:- mode recursion_type_get_maybe_avg_max_depth(in, out) is det.
%----------------------------------------------------------------------------%
%----------------------------------------------------------------------------%
:- implementation.
:- import_module analysis_utils.
:- import_module array_util.
:- import_module coverage.
:- import_module create_report.
:- import_module mdbcomp.
:- import_module mdbcomp.goal_path.
:- import_module mdbcomp.program_representation.
:- import_module measurement_units.
:- import_module array.
:- import_module assoc_list.
:- import_module float.
:- import_module int.
:- import_module io.
:- import_module list.
:- import_module map.
:- import_module pair.
:- import_module require.
:- import_module set.
:- import_module string.
:- import_module unit.
%----------------------------------------------------------------------------%
create_clique_recursion_costs_report(Deep, CliquePtr,
MaybeCliqueRecursionReport) :-
find_clique_first_and_other_procs(Deep, CliquePtr, MaybeFirstPDPtr,
OtherPDPtrs),
deep_lookup_clique_parents(Deep, CliquePtr, ParentCallPtr),
( if valid_call_site_dynamic_ptr(Deep, ParentCallPtr) then
deep_lookup_call_site_dynamics(Deep, ParentCallPtr, ParentCall),
ParentCalls = calls(ParentCall ^ csd_own_prof)
else
% The first call from the runtime doesn't have a valid CSD.
ParentCalls = 1
),
(
MaybeFirstPDPtr = yes(FirstPDPtr),
NumProcs = length(OtherPDPtrs) + 1,
(
OtherPDPtrs = [],
% Exaclty one procedure
proc_get_recursion_type(Deep, CliquePtr, FirstPDPtr, ParentCalls,
MaybeRecursionType)
;
OtherPDPtrs = [_ | _],
% More than one, this is some sort of multiply recursion.
MaybeRecursionType = ok(rt_mutual_recursion(NumProcs))
),
(
MaybeRecursionType = ok(RecursionType),
CliqueRecursionReport = clique_recursion_report(CliquePtr,
RecursionType, NumProcs),
MaybeCliqueRecursionReport = ok(CliqueRecursionReport)
;
MaybeRecursionType = error(Error),
MaybeCliqueRecursionReport = error(Error)
)
;
MaybeFirstPDPtr = no,
MaybeCliqueRecursionReport = error(
"This clique doesn't appear to have an entry procedure")
).
:- pred proc_get_recursion_type(deep::in, clique_ptr::in,
proc_dynamic_ptr::in, int::in, maybe_error(recursion_type)::out) is det.
proc_get_recursion_type(Deep, ThisClique, PDPtr, ParentCalls,
MaybeRecursionType) :-
deep_lookup_pd_own(Deep, PDPtr, PDOwn),
TotalCalls = calls(PDOwn),
create_dynamic_procrep_coverage_report(Deep, PDPtr, MaybeCoverageReport),
(
MaybeCoverageReport = ok(CoverageReport),
CoverageReport = procrep_coverage_info(_, ProcRep, CoverageArray),
Goal = ProcRep ^ pr_defn ^ pdr_goal,
proc_dynamic_paired_call_site_slots(Deep, PDPtr, Slots),
foldl(build_dynamic_call_site_cost_and_callee_map(Deep),
Slots, map.init, CallSitesMap),
Info = recursion_analysis_info(ThisClique, CallSitesMap,
CoverageArray),
goal_recursion_data(Info, rgp_nil, Goal, RecursionData),
recursion_data_to_recursion_type(ParentCalls, TotalCalls,
RecursionData, RecursionType),
MaybeRecursionType = ok(RecursionType)
;
MaybeCoverageReport = error(Error),
MaybeRecursionType = error(Error)
).
:- pred recursion_data_to_recursion_type(int::in, int::in, recursion_data::in,
recursion_type::out) is det.
recursion_data_to_recursion_type(ParentCallsI, TotalCallsI,
RecursionData, Type) :-
(
RecursionData = no_recursion_data_dead_proc,
% A procedure that is never called never recurses.
Type = rt_not_recursive
;
RecursionData = recursion_data(Levels, Maximum, Errors),
ParentCalls = float(ParentCallsI),
TotalCalls = float(TotalCallsI),
( if assoc_list.search(Levels, 0, RLBase) then
RLBase = recursion_level(BaseCost, BaseProb),
BaseCountF = probability_to_float(BaseProb) * TotalCalls,
BaseCount = round_to_int(BaseCountF)
else
BaseCost = 0.0,
BaseCount = 0,
BaseProb = impossible
),
BaseLevel =
recursion_level_report(0, BaseCount, BaseProb, BaseCost, 0.0),
( if set.empty(Errors) then
( if Maximum < 0 then
unexpected($module, $pred,
"negative number of recursive calls")
else if Maximum = 0 then
Type = rt_not_recursive
else if Maximum = 1 then
( if assoc_list.search(Levels, 1, RLRec) then
RLRec = recursion_level(RecCost, RecProb),
RecCountF = probability_to_float(RecProb) * TotalCalls,
RecLevel = recursion_level_report(1,
round_to_int(RecCountF), RecProb, RecCost, 1.0)
else
string.format("maximum level %d not found", [i(1)], Msg),
unexpected($module, $pred, Msg)
),
AvgMaxDepth = TotalCalls / ParentCalls,
AvgRecCost = single_rec_average_recursion_cost(BaseCost,
RecCost, AvgMaxDepth),
AnyRecCost = single_rec_recursion_cost(BaseCost, RecCost),
Type = rt_single(BaseLevel, RecLevel, AvgMaxDepth, AvgRecCost,
AnyRecCost)
else if
Maximum = 2,
not assoc_list.search(Levels, 1, _)
then
( if assoc_list.search(Levels, 2, RLRec) then
RLRec = recursion_level(RecCost, RecProb),
RecCountF = probability_to_float(RecProb) * ParentCalls,
RecLevel = recursion_level_report(2,
round_to_int(RecCountF), RecProb, RecCost,
RecCountF*2.0)
else
string.format("maximum level %d not found", [i(1)], Msg),
unexpected($module, $pred, Msg)
),
Type = rt_divide_and_conquer(BaseLevel, RecLevel)
else
list.map(recursion_level_report(TotalCalls), Levels,
LevelsReport),
Type = rt_other(LevelsReport)
)
else
Messages = list.map(error_to_string, to_sorted_list(Errors)),
Type = rt_errors(Messages)
)
).
:- pred recursion_level_report(float::in, pair(int, recursion_level)::in,
recursion_level_report::out) is det.
recursion_level_report(TotalCalls, Level - recursion_level(NonRecCost, Prob),
recursion_level_report(Level, Calls, Prob, NonRecCost, CostExChild)) :-
CallsF = probability_to_float(Prob) * TotalCalls,
Calls = round_to_int(CallsF),
CostExChild = float(Level) * CallsF.
% This uses the formula.
%
% Base + Shared + Level (Rec + Shared) = Cost.
%
% To calculate the Cost of a recursive call at a depth of Level in a singly
% recursive procedure from:
% Base - The cost of the base case.
% Rec - The cost of the recursive call except for the recursive call
% itself.
% Shared - The cost of code common to both cases.
%
% The + 1.0 counts for the cost of the recursive call itself, The Shared
% variable has already been factored into BaseCost and RecCost.
%
:- func single_rec_recursion_cost(float, float, int) = float.
single_rec_recursion_cost(BaseCost, RecCost, LevelI) = Cost :-
Cost = BaseCost + (float(LevelI) * (RecCost + 1.0)).
% This formula is derived as follows.
%
% It's the average (sum of all recursion levels divided by number of
% levels).
%
% Sum l in 0..MaxLevel ( Base + l * Rec ) / ( MaxLevel + 1 )
%
% Factor out the cost of the base case and start the sum from level 1 in
% the recursive case.
%
% ( Base(MaxLevel + 1) + Sum l in 1..MaxLevel ( l * Rec ) ) /
% ( MaxLevel + 1 )
%
% Simplify.
%
% Base + Sum l in 1..MaxLevel ( i * Rec ) / (MaxLevel + 1)
%
% Recall that Sum i in 1..N (i) = (N^2 + N) / 2
%
% Base + (((L^2 + L) * Rec) / 2) / (MaxLevel + 1)
%
:- func single_rec_average_recursion_cost(float, float, float) = float.
single_rec_average_recursion_cost(BaseCost, RecCost, AvgMaxDepth) = Cost :-
Sum = 0.5 * RecCost * ((AvgMaxDepth * AvgMaxDepth) + AvgMaxDepth),
Cost = BaseCost + ((Sum) / (AvgMaxDepth + 1.0)).
%----------------------------------------------------------------------------%
:- type recursion_data
---> no_recursion_data_dead_proc
% There is no recursion data for this proc, since it is
% never called.
; recursion_data(
rd_recursions :: assoc_list(int, recursion_level),
rd_maximum :: int,
rd_errors :: set(recursion_error)
).
:- type recursion_level
---> recursion_level(
rl_cost :: float,
% The probability the path leading to this recursion level is
% called given that the goal is called.
rl_probability :: probability
).
:- type recursion_error
---> re_unhandled_determinism(detism_rep).
:- type recursion_analysis_info
---> recursion_analysis_info(
rai_this_clique :: clique_ptr,
rai_call_sites ::
map(reverse_goal_path, cost_and_callees),
rai_coverage_info :: goal_attr_array(coverage_info)
).
% goal_recursion_data(RecursiveCallees, Goal, GoalPath,
% init_recursion_data, RecursionData)
%
% Compute RecursionData about Goal if RecursiveCalls are calls
% that may eventually lead to Goal.
%
:- pred goal_recursion_data(recursion_analysis_info::in,
reverse_goal_path::in, goal_rep(goal_id)::in, recursion_data::out)
is det.
goal_recursion_data(Info, RevGoalPath, GoalRep, !:RecursionData) :-
GoalRep = goal_rep(GoalExpr, Detism, GoalId),
CoverageInfo = get_goal_attribute_det(Info ^ rai_coverage_info, GoalId),
( if get_coverage_before(CoverageInfo, CallsPrime) then
Calls = CallsPrime
else
unexpected($module, $pred, "couldn't retrieve coverage information")
),
( if Calls = 0 then
!:RecursionData = no_recursion_data_dead_proc
else
(
GoalExpr = conj_rep(Conjs),
conj_recursion_data(Info, RevGoalPath, 1, Conjs,
!:RecursionData)
;
GoalExpr = disj_rep(Disjs),
disj_recursion_data(Info, RevGoalPath, 1, Disjs,
!:RecursionData)
;
GoalExpr = switch_rep(_, _, Cases),
switch_recursion_data(Info, RevGoalPath, 1, Cases,
float(Calls), Calls, !:RecursionData)
;
GoalExpr = ite_rep(Cond, Then, Else),
ite_recursion_data(Info, RevGoalPath, Cond, Then, Else,
Calls, !:RecursionData)
;
(
GoalExpr = negation_rep(SubGoal),
GoalPathStep = step_neg
;
GoalExpr = scope_rep(SubGoal, MaybeCut),
GoalPathStep = step_scope(MaybeCut)
),
goal_recursion_data(Info, rgp_cons(RevGoalPath, GoalPathStep),
SubGoal, !:RecursionData)
;
GoalExpr = atomic_goal_rep(_, _, _, AtomicGoalRep),
atomic_goal_recursion_data(Info, RevGoalPath, AtomicGoalRep,
!:RecursionData)
)
),
(
( Detism = det_rep
; Detism = semidet_rep
; Detism = cc_nondet_rep
; Detism = cc_multidet_rep
; Detism = erroneous_rep
; Detism = failure_rep
)
;
( Detism = nondet_rep
; Detism = multidet_rep
),
recursion_data_add_error(re_unhandled_determinism(Detism),
!RecursionData)
).
:- pred conj_recursion_data(recursion_analysis_info::in,
reverse_goal_path::in, int::in, list(goal_rep(goal_id))::in,
recursion_data::out) is det.
conj_recursion_data(_, _, _, [], simple_recursion_data(0.0, 0)).
% An empty conjunction represents "true", so there is
% exactly one trivial path through it with 0 recursive calls.
conj_recursion_data(Info, RevGoalPath, ConjNum, [Conj | Conjs],
RecursionData) :-
goal_recursion_data(Info, rgp_cons(RevGoalPath, step_conj(ConjNum)), Conj,
ConjRecursionData),
(
ConjRecursionData = no_recursion_data_dead_proc,
% If the first conjunct is dead then the remaining ones will
% also be dead. This speeds up execution and avoids a divide by zero
% when calculating ConjSuccessProb below.
RecursionData = no_recursion_data_dead_proc
;
ConjRecursionData = recursion_data(_, _, _),
conj_recursion_data(Info, RevGoalPath, ConjNum + 1, Conjs,
ConjsRecursionData0),
CanFail = detism_get_can_fail(Conj ^ goal_detism_rep),
(
CanFail = cannot_fail_rep,
merge_recursion_data_sequence(ConjRecursionData,
ConjsRecursionData0, RecursionData)
;
CanFail = can_fail_rep,
% It's possible that the conjunct can fail, in that case the code
% branches into one branch that continues with the conjunction and
% one that doesn't.
CoverageInfo = get_goal_attribute_det(Info ^ rai_coverage_info,
Conj ^ goal_annotation),
success_probability_from_coverage(CoverageInfo, ConjSuccessProb),
recursion_data_and_probability(ConjSuccessProb,
ConjsRecursionData0, ConjsRecursionData),
ConjFailureProb = not_probability(ConjSuccessProb),
Failure0 = simple_recursion_data(0.0, 0),
recursion_data_and_probability(ConjFailureProb, Failure0, Failure),
merge_recursion_data_after_branch(ConjsRecursionData, Failure,
BranchRecursionData),
merge_recursion_data_sequence(ConjRecursionData,
BranchRecursionData, RecursionData)
)
).
:- pred disj_recursion_data(recursion_analysis_info::in,
reverse_goal_path::in, int::in, list(goal_rep(goal_id))::in,
recursion_data::out) is det.
disj_recursion_data(_, _, _, [], simple_recursion_data(0.0, 0)).
disj_recursion_data(Info, RevGoalPath, DisjNum, [Disj | Disjs],
RecursionData) :-
% Handle only semidet and committed-choice disjunctions, which cannot be
% re-entered once a disjunct succeeds.
goal_recursion_data(Info, rgp_cons(RevGoalPath, step_disj(DisjNum)), Disj,
DisjRecursionData),
(
DisjRecursionData = no_recursion_data_dead_proc,
% If the first disjunct was never tried, then no other disjuncts will
% ever be tried.
RecursionData = no_recursion_data_dead_proc
;
DisjRecursionData = recursion_data(_, _, _),
CoverageInfo = get_goal_attribute_det(Info ^ rai_coverage_info,
Disj ^ goal_annotation),
success_probability_from_coverage(CoverageInfo,
DisjSuccessProb),
DisjFailureProb = not_probability(DisjSuccessProb),
% The code can branch here, either it tries the next disjuct, which we
% represent as DisjsRecursionData, ...
disj_recursion_data(Info, RevGoalPath, DisjNum + 1, Disjs,
DisjsRecursionData0),
recursion_data_and_probability(DisjFailureProb, DisjsRecursionData0,
DisjsRecursionData),
% ... or it succeeds, which we represent as finished.
Finish0 = simple_recursion_data(0.0, 0),
recursion_data_and_probability(DisjSuccessProb, Finish0, Finish),
% Then the result the branch of (DisjsRecursionData or finish) appended
% to DisjRecursionData.
merge_recursion_data_after_branch(Finish, DisjsRecursionData,
BranchRecursionData),
merge_recursion_data_sequence(DisjRecursionData, BranchRecursionData,
RecursionData)
).
:- pred success_probability_from_coverage(coverage_info::in, probability::out)
is det.
success_probability_from_coverage(Coverage, SuccessProb) :-
( if get_coverage_before_and_after(Coverage, Before, After) then
( if After > Before then
% Nondet code can overflow this probability.
SuccessProb = certain
else
SuccessProb = probable(float(After) / float(Before))
)
else
unexpected($module, $pred, "expected complete coverage information")
).
:- pred ite_recursion_data(recursion_analysis_info::in,
reverse_goal_path::in,
goal_rep(goal_id)::in, goal_rep(goal_id)::in, goal_rep(goal_id)::in,
int::in, recursion_data::out) is det.
ite_recursion_data(Info, RevGoalPath, Cond, Then, Else, Calls,
!:RecursionData) :-
goal_recursion_data(Info, rgp_cons(RevGoalPath, step_ite_cond), Cond,
CondRecursionData),
goal_recursion_data(Info, rgp_cons(RevGoalPath, step_ite_then), Then,
ThenRecursionData0),
goal_recursion_data(Info, rgp_cons(RevGoalPath, step_ite_else), Else,
ElseRecursionData0),
% Adjust the probabilities of executing the then and else branches.
Coverage = Info ^ rai_coverage_info,
ThenCoverageInfo =
get_goal_attribute_det(Coverage, Then ^ goal_annotation),
ElseCoverageInfo =
get_goal_attribute_det(Coverage, Else ^ goal_annotation),
get_coverage_before_det(ThenCoverageInfo, ThenCalls),
get_coverage_before_det(ElseCoverageInfo, ElseCalls),
CallsF = float(Calls),
ThenProb = probable(float(ThenCalls) / CallsF),
ElseProb = probable(float(ElseCalls) / CallsF),
recursion_data_and_probability(ThenProb,
ThenRecursionData0, ThenRecursionData),
recursion_data_and_probability(ElseProb,
ElseRecursionData0, ElseRecursionData),
% Because the condition goal has coverage information as if it is
% entered before either branch, we have to model it in the same way here,
% even though it would be feasible to model it as something that happens
% in sequence with both the then and else branches (within each branch).
merge_recursion_data_after_branch(ThenRecursionData,
ElseRecursionData, !:RecursionData),
merge_recursion_data_sequence(CondRecursionData, !RecursionData).
:- pred switch_recursion_data(recursion_analysis_info::in,
reverse_goal_path::in, int::in, list(case_rep(goal_id))::in,
float::in, int::in, recursion_data::out) is det.
switch_recursion_data(_, _, _, [], TotalCalls, CallsRemaining,
RecursionData) :-
% Can fail switches will have a nonzero probability of reaching this case.
FailProb = probable(float(CallsRemaining) / TotalCalls),
RecursionData0 = simple_recursion_data(0.0, 0),
recursion_data_and_probability(FailProb, RecursionData0, RecursionData).
switch_recursion_data(Info, RevGoalPath, CaseNum, [Case | Cases],
TotalCalls, CallsRemaining, RecursionData) :-
Case = case_rep(_, _, Goal),
RevArmPath = rgp_cons(RevGoalPath,
step_switch(CaseNum, unknown_num_functors_in_type)),
goal_recursion_data(Info, RevArmPath, Goal, CaseRecursionData0),
CoverageInfo = get_goal_attribute_det(Info ^ rai_coverage_info,
Goal ^ goal_annotation),
( if get_coverage_before(CoverageInfo, CallsPrime) then
Calls = CallsPrime
else
unexpected($module, $pred, "expected coverage information")
),
CaseProb = probable(float(Calls) / TotalCalls),
recursion_data_and_probability(CaseProb, CaseRecursionData0,
CaseRecursionData),
switch_recursion_data(Info, RevGoalPath, CaseNum+1,
Cases, TotalCalls, CallsRemaining - Calls, CasesRecursionData),
merge_recursion_data_after_branch(CaseRecursionData, CasesRecursionData,
RecursionData).
:- pred atomic_goal_recursion_data(recursion_analysis_info::in,
reverse_goal_path::in, atomic_goal_rep::in, recursion_data::out) is det.
atomic_goal_recursion_data(Info, RevGoalPath, AtomicGoal, RecursionData) :-
(
% All these things have trivial cost except for foreign code whose cost
% is unknown (which because it doesn't contribute to the cost of the
% caller we assume that it is trivial)..
( AtomicGoal = unify_construct_rep(_, _, _)
; AtomicGoal = unify_deconstruct_rep(_, _, _)
; AtomicGoal = partial_deconstruct_rep(_, _, _)
; AtomicGoal = partial_construct_rep(_, _, _)
; AtomicGoal = unify_assign_rep(_, _)
; AtomicGoal = cast_rep(_, _)
; AtomicGoal = unify_simple_test_rep(_, _)
; AtomicGoal = pragma_foreign_code_rep(_)
; AtomicGoal = builtin_call_rep(_, _, _)
; AtomicGoal = event_call_rep(_, _)
),
RecursionLevel = 0 - recursion_level(0.0, certain)
;
( AtomicGoal = higher_order_call_rep(_, _)
; AtomicGoal = method_call_rep(_, _, _)
; AtomicGoal = plain_call_rep(_, _, _)
),
% Get the cost of the call.
Info = recursion_analysis_info(ThisClique, CallSiteMap, _),
map.lookup(CallSiteMap, RevGoalPath, CostAndCallees),
( if cost_and_callees_is_recursive(ThisClique, CostAndCallees) then
% Cost will be 1.0 for for each call to recursive calls but we
% calculate this later.
RecursionLevel = 1 - recursion_level(0.0, certain)
else
CostPercall = cs_cost_get_percall(CostAndCallees ^ cac_cost),
RecursionLevel = 0 - recursion_level(CostPercall, certain)
)
),
RecursionLevel = RecursiveCalls - _,
RecursionData = recursion_data([RecursionLevel], RecursiveCalls, init).
% Consider the following nested switches:
%
% (
% (
% base1
% ;
% rec1
% )
% ;
% (
% base2
% ;
% rec2
% )
% )
%
% + The cost of entering a base case is the weighted average of the costs
% of the two base cases.
% + The number of times one enters a base case is the sum of the
% individual counts.
% + The above two rules are also true for recursive cases.
%
:- pred merge_recursion_data_after_branch(recursion_data::in,
recursion_data::in, recursion_data::out) is det.
merge_recursion_data_after_branch(A, B, Result) :-
(
A = recursion_data(RecursionsA, MaxLevelA, ErrorsA),
B = recursion_data(RecursionsB, MaxLevelB, ErrorsB),
Recursions0 = assoc_list.merge(RecursionsA, RecursionsB),
condense_recursions(Recursions0, Recursions),
MaxLevel = max(MaxLevelA, MaxLevelB),
Errors = union(ErrorsA, ErrorsB),
Result = recursion_data(Recursions, MaxLevel, Errors)
;
A = recursion_data(_, _, _),
B = no_recursion_data_dead_proc,
Result = A
;
A = no_recursion_data_dead_proc,
B = recursion_data(_, _, _),
Result = B
;
A = no_recursion_data_dead_proc,
B = no_recursion_data_dead_proc,
Result = no_recursion_data_dead_proc
).
% merge_recursion_data_sequence(A, B, Merged).
%
% Merge the recursion datas A and B to produce Merged.
% This is not commutative; A must represent something occurring before B.
%
% Consider the following conjoined switches.
%
% (
% base1
% ;
% rec1
% ),
% (
% base2
% ;
% rec2
% )
%
% It's like algebra! Treating the conjunction as multiplication and
% disjunction as addition we might factorise it as:
%
% base1*base2 + base1*rec2 + base2*rec1 + rec1*rec2.
%
% That is, there is one base case, two recursive cases, and a doubly
% recursive case.
%
% We have to convert counts to probabilities, then:
%
% + The probability of entering the base case is the product of the
% probabilities of entering either base case.
% + Similarly the probability of entering any other case is the product the
% probabilities of their components.
% + The cost of entering the base case is the sum of the costs of the
% components.
% + Similarly for the other cases.
%
:- pred merge_recursion_data_sequence(recursion_data::in,
recursion_data::in, recursion_data::out) is det.
merge_recursion_data_sequence(A, B, Result) :-
(
A = recursion_data(RecursionsA, MaxLevelA, ErrorsA),
B = recursion_data(RecursionsB, MaxLevelB, ErrorsB),
recursions_cross_product(RecursionsA, RecursionsB, Recursions0),
sort(Recursions0, Recursions1),
condense_recursions(Recursions1, Recursions),
% The maximum number of recursions on any path will be the sum of
% the maximum number of recursions on the two conjoined paths,
% since all paths are conjoined in the cross product.
MaxLevel = MaxLevelA + MaxLevelB,
Errors = union(ErrorsA, ErrorsB),
Result = recursion_data(Recursions, MaxLevel, Errors)
;
A = recursion_data(_, _, _),
B = no_recursion_data_dead_proc,
Result = no_recursion_data_dead_proc
;
A = no_recursion_data_dead_proc,
Result = no_recursion_data_dead_proc
).
:- pred condense_recursions(assoc_list(int, recursion_level)::in,
assoc_list(int, recursion_level)::out) is det.
condense_recursions([], []).
condense_recursions([Num - Rec | Pairs0], Pairs) :-
condense_recursions_2(Num - Rec, Pairs0, Pairs).
:- pred condense_recursions_2(pair(int, recursion_level)::in,
assoc_list(int, recursion_level)::in,
assoc_list(int, recursion_level)::out) is det.
condense_recursions_2(Pair, [], [Pair]).
condense_recursions_2(NumA - RecA, [NumB - RecB | Pairs0], Pairs) :-
( if NumA = NumB then
RecA = recursion_level(CostA, ProbabilityA),
RecB = recursion_level(CostB, ProbabilityB),
weighted_average(
[probability_to_float(ProbabilityA),
probability_to_float(ProbabilityB)],
[CostA, CostB], Cost),
Probability = or(ProbabilityA, ProbabilityB),
Rec = recursion_level(Cost, Probability),
condense_recursions_2(NumA - Rec, Pairs0, Pairs)
else
condense_recursions([NumB - RecB | Pairs0], Pairs1),
Pairs = [NumA - RecA | Pairs1]
).
% recursions_cross_product(A, B, C).
%
% A X B = C <=> A.1 * B.1 + A.1 * B.2 + A.2 * B.1 + A.2 * B.2 = C
%
% Note that this is not commutative. A represents a computation occurring
% before B.
%
:- pred recursions_cross_product(assoc_list(int, recursion_level)::in,
assoc_list(int, recursion_level)::in,
assoc_list(int, recursion_level)::out) is det.
recursions_cross_product([], _, []).
recursions_cross_product([NumA - RecA | PairsA], PairsB, Pairs) :-
recursions_cross_product_2(NumA, RecA, PairsB, InnerLoop),
recursions_cross_product(PairsA, PairsB, OuterLoopTail),
Pairs = InnerLoop ++ OuterLoopTail.
:- pred recursions_cross_product_2(int::in, recursion_level::in,
assoc_list(int, recursion_level)::in,
assoc_list(int, recursion_level)::out) is det.
recursions_cross_product_2(_Num, _Rec, [], []).
recursions_cross_product_2(NumA, RecA@recursion_level(CostA, ProbA),
[NumB - recursion_level(CostB, ProbB) | PairsB], Pairs) :-
recursions_cross_product_2(NumA, RecA, PairsB, Pairs0),
Num = NumA + NumB,
Prob = and(ProbA, ProbB),
Cost = CostA + CostB,
Pair = Num - recursion_level(Cost, Prob),
Pairs = [Pair | Pairs0].
:- pred recursion_data_and_probability(probability::in, recursion_data::in,
recursion_data::out) is det.
recursion_data_and_probability(Prob,
recursion_data(!.Recursions, MaxLevel, Errors),
recursion_data(!:Recursions, MaxLevel, Errors)) :-
map_values(recursion_level_and_probability(Prob), !Recursions).
recursion_data_and_probability(_,
no_recursion_data_dead_proc,
no_recursion_data_dead_proc).
:- pred recursion_level_and_probability(probability::in, T::in,
recursion_level::in, recursion_level::out) is det.
recursion_level_and_probability(AndProb, _,
recursion_level(Cost, Prob0), recursion_level(Cost, Prob)) :-
Prob = and(Prob0, AndProb).
:- pred recursion_data_add_error(recursion_error::in, recursion_data::in,
recursion_data::out) is det.
recursion_data_add_error(Error, !RecursionData) :-
some [!Errors] (
(
!.RecursionData = recursion_data(_, _, !:Errors),
set.insert(Error, !Errors),
!RecursionData ^ rd_errors := !.Errors
;
!.RecursionData = no_recursion_data_dead_proc
)
).
% simple_recursion_data(Cost, RecCalls) = RecursionData.
%
% Create a simple recursion data item from a single level.
%
:- func simple_recursion_data(float, int) = recursion_data.
simple_recursion_data(Cost, Calls) =
recursion_data([Calls - recursion_level(Cost, certain)], Calls, init).
:- func error_to_string(recursion_error) = string.
error_to_string(re_unhandled_determinism(Detism)) =
format("%s code is not handled", [s(string(Detism))]).
%----------------------------------------------------------------------------%
create_recursion_types_frequency_report(Deep, MaybeReport) :-
% This report is impossible without procrep data, but we don't use it
% directly.
MaybeProgRepResult = Deep ^ procrep_file,
(
MaybeProgRepResult = no,
MaybeReport = error("There is no readable " ++
"procedure representation information file.")
;
MaybeProgRepResult = yes(error(Error)),
MaybeReport = error("Error reading procedure representation " ++
"information file: " ++ Error)
;
MaybeProgRepResult = yes(ok(_)),
Cliques = Deep ^ clique_index,
size(Cliques, NumCliques),
array_foldl_from_1(rec_types_freq_build_histogram(Deep), Cliques,
map.init, Histogram0),
finalize_histogram(Deep, NumCliques, Histogram0, Histogram),
MaybeReport = ok(recursion_types_frequency_report(Histogram))
).
:- pred rec_types_freq_build_histogram(deep::in, int::in, clique_ptr::in,
map(recursion_type_simple, recursion_type_raw_freq_data)::in,
map(recursion_type_simple, recursion_type_raw_freq_data)::out) is det.
rec_types_freq_build_histogram(Deep, _, CliquePtr, !Histogram) :-
trace [io(!IO)] (
clique_ptr(CliqueNum) = CliquePtr,
io.format("Analyzing clique: %d\n", [i(CliqueNum)], !IO)
),
create_clique_recursion_costs_report(Deep, CliquePtr,
MaybeCliqueRecursionReport),
(
MaybeCliqueRecursionReport = ok(CliqueRecursionReport),
Type = CliqueRecursionReport ^ crr_recursion_type,
recursion_type_to_simple_type(Type, SimpleTypes)
;
MaybeCliqueRecursionReport = error(Error),
SimpleTypes = [rts_error(Error), rts_total_error_instances]
),
find_clique_first_and_other_procs(Deep, CliquePtr, MaybeFirstPDPtr,
_OtherPDPtrs),
(
MaybeFirstPDPtr = yes(FirstPDPtr),
lookup_proc_dynamics(Deep ^ proc_dynamics, FirstPDPtr, FirstPD),
FirstPSPtr = FirstPD ^ pd_proc_static,
PDesc = describe_proc(Deep, FirstPSPtr),
lookup_pd_own(Deep ^ pd_own, FirstPDPtr, ProcOwn),
lookup_pd_desc(Deep ^ pd_desc, FirstPDPtr, ProcInherit),
FirstProcInfo = first_proc_info(PDesc,
own_and_inherit_prof_info(ProcOwn, ProcInherit)),
MaybeFirstProcInfo = yes(FirstProcInfo)
;
MaybeFirstPDPtr = no,
MaybeFirstProcInfo = no
),
list.foldl(update_histogram(MaybeFirstProcInfo), SimpleTypes, !Histogram).
:- type first_proc_info
---> first_proc_info(
fpi_pdesc :: proc_desc,
fpi_prof_info :: own_and_inherit_prof_info
).
% XXX Consider moving this to measurements.m
%
:- type own_and_inherit_prof_info
---> own_and_inherit_prof_info(
oai_own :: own_prof_info,
oai_inherit :: inherit_prof_info
).
:- pred add_own_and_inherit_prof_info(own_and_inherit_prof_info::in,
own_and_inherit_prof_info::in, own_and_inherit_prof_info::out) is det.
add_own_and_inherit_prof_info(
own_and_inherit_prof_info(OwnA, InheritA),
own_and_inherit_prof_info(OwnB, InheritB),
own_and_inherit_prof_info(Own, Inherit)) :-
Own = add_own_to_own(OwnA, OwnB),
Inherit = add_inherit_to_inherit(InheritA, InheritB).
:- type recursion_type_raw_freq_data
---> recursion_type_raw_freq_data(
rtrfd_freq :: int,
rtrfd_maybe_prof_info :: maybe(own_and_inherit_prof_info),
rtrfd_entry_procs :: map(proc_static_ptr,
recursion_type_raw_proc_freq_data)
).
:- type recursion_type_raw_proc_freq_data
---> recursion_type_raw_proc_freq_data(
rtrpfd_freq :: int,
rtrpfd_prof_info :: own_and_inherit_prof_info,
rtrpfd_proc_desc :: proc_desc
).
:- pred update_histogram(maybe(first_proc_info)::in,
recursion_type_simple::in,
map(recursion_type_simple, recursion_type_raw_freq_data)::in,
map(recursion_type_simple, recursion_type_raw_freq_data)::out) is det.
update_histogram(MaybeFirstProcInfo, SimpleType, !Histogram) :-
( if map.search(!.Histogram, SimpleType, Data0) then
Data0 = recursion_type_raw_freq_data(Count0, MaybeProfInfo0, Procs0),
(
MaybeFirstProcInfo = yes(FirstProcInfo),
(
MaybeProfInfo0 = yes(ProfInfo0),
add_own_and_inherit_prof_info(FirstProcInfo ^ fpi_prof_info,
ProfInfo0, ProfInfo)
;
MaybeProfInfo0 = no,
ProfInfo = FirstProcInfo ^ fpi_prof_info
),
MaybeProfInfo = yes(ProfInfo),
update_procs_map(FirstProcInfo, Procs0, Procs)
;
MaybeFirstProcInfo = no,
MaybeProfInfo = MaybeProfInfo0,
Procs = Procs0
),
Count = Count0 + 1,
Data = recursion_type_raw_freq_data(Count, MaybeProfInfo, Procs)
else
Count = 1,
(
MaybeFirstProcInfo = yes(FirstProcInfo),
MaybeProfInfo = yes(FirstProcInfo ^ fpi_prof_info),
update_procs_map(FirstProcInfo, map.init, Procs)
;
MaybeFirstProcInfo = no,
MaybeProfInfo = no,
Procs = map.init
),
Data = recursion_type_raw_freq_data(Count, MaybeProfInfo, Procs)
),
map.set(SimpleType, Data, !Histogram).
:- pred update_procs_map(first_proc_info::in,
map(proc_static_ptr, recursion_type_raw_proc_freq_data)::in,
map(proc_static_ptr, recursion_type_raw_proc_freq_data)::out) is det.
update_procs_map(FirstProcInfo, !Map) :-
FirstProcInfo = first_proc_info(PSDesc, FirstProfInfo),
PsPtr = PSDesc ^ pdesc_ps_ptr,
( if map.search(!.Map, PsPtr, ProcFreqData0) then
ProcFreqData0 =
recursion_type_raw_proc_freq_data(Count0, ProfInfo0, ProcDesc),
add_own_and_inherit_prof_info(FirstProfInfo, ProfInfo0, ProfInfo),
Count = Count0 + 1,
ProcFreqData =
recursion_type_raw_proc_freq_data(Count, ProfInfo, ProcDesc)
else
ProcFreqData =
recursion_type_raw_proc_freq_data(1, FirstProfInfo, PSDesc)
),
map.set(PsPtr, ProcFreqData, !Map).
:- pred recursion_type_to_simple_type(recursion_type::in,
list(recursion_type_simple)::out) is det.
recursion_type_to_simple_type(rt_not_recursive, [rts_not_recursive]).
recursion_type_to_simple_type(rt_single(_, _, _, _, _), [rts_single]).
recursion_type_to_simple_type(rt_divide_and_conquer(_, _),
[rts_divide_and_conquer]).
recursion_type_to_simple_type(rt_mutual_recursion(NumProcs),
[rts_mutual_recursion(NumProcs)]).
recursion_type_to_simple_type(rt_other(Levels), [rts_other(SimpleLevels)]) :-
SimpleLevels = set.from_list(
map((func(Level) = Level ^ rlr_level), Levels)).
recursion_type_to_simple_type(rt_errors(Errors), SimpleTypes) :-
SimpleTypes =
list.map((func(E) = rts_error(E)), Errors)
++ [rts_total_error_instances].
:- pred finalize_histogram(deep::in, int::in,
map(recursion_type_simple, recursion_type_raw_freq_data)::in,
map(recursion_type_simple, recursion_type_freq_data)::out) is det.
finalize_histogram(Deep, NumCliques, !Histogram) :-
map_values(finalize_histogram_rec_type(Deep, float(NumCliques)),
!Histogram).
:- pred finalize_histogram_rec_type(deep::in, float::in,
recursion_type_simple::in,
recursion_type_raw_freq_data::in, recursion_type_freq_data::out) is det.
finalize_histogram_rec_type(Deep, NumCliques, _RecursionType,
recursion_type_raw_freq_data(Freq, MaybeProfInfo, !.EntryProcs),
recursion_type_freq_data(Freq, Percent, MaybeSummary, !:EntryProcs)) :-
Percent = percent(float(Freq) / NumCliques),
(
MaybeProfInfo = no,
MaybeSummary = no
;
MaybeProfInfo = yes(ProfInfo),
ProfInfo = own_and_inherit_prof_info(Own, Inherit),
own_and_inherit_to_perf_row_data(Deep, unit, Own, Inherit, Summary),
MaybeSummary = yes(Summary)
),
map_values(finalize_histogram_proc_rec_type(Deep, NumCliques),
!EntryProcs).
:- pred finalize_histogram_proc_rec_type(deep::in, float::in,
proc_static_ptr::in,
recursion_type_raw_proc_freq_data::in, recursion_type_proc_freq_data::out)
is det.
finalize_histogram_proc_rec_type(Deep, NumCliques, _PSPtr,
recursion_type_raw_proc_freq_data(Freq, ProfInfo, ProcDesc),
recursion_type_proc_freq_data(Freq, Percent, Summary)) :-
Percent = percent(float(Freq) / NumCliques),
ProfInfo = own_and_inherit_prof_info(Own, Inherit),
own_and_inherit_to_perf_row_data(Deep, ProcDesc, Own, Inherit, Summary).
%----------------------------------------------------------------------------%
%----------------------------------------------------------------------------%
recursion_type_get_maybe_avg_max_depth(rt_not_recursive,
yes(recursion_depth_from_float(0.0))).
recursion_type_get_maybe_avg_max_depth(rt_single(_, _, Depth, _, _),
yes(recursion_depth_from_float(Depth))).
recursion_type_get_maybe_avg_max_depth(rt_divide_and_conquer(_, _), no).
recursion_type_get_maybe_avg_max_depth(rt_mutual_recursion(_), no).
recursion_type_get_maybe_avg_max_depth(rt_other(_), no).
recursion_type_get_maybe_avg_max_depth(rt_errors(_), no).
%----------------------------------------------------------------------------%
:- end_module recursion_patterns.
%----------------------------------------------------------------------------%