[m-rev.] diff: Coverage propagation cleanups.
Paul Bone
pbone at csse.unimelb.edu.au
Tue Oct 7 20:29:12 AEDT 2008
Estimated hours taken: 0.5
Branches: main
Cleaning up of coverage propagation code. In particular I've addressed issues
that were flagged as 'XXX' by Zoltan. I've also relaxed some of the checking
code that was written assuming exceptions were never used.
deep_profiler/program_representation_utils.m:
As above.
Index: deep_profiler/program_representation_utils.m
===================================================================
RCS file: /home/mercury1/repository/mercury/deep_profiler/program_representation_utils.m,v
retrieving revision 1.14
diff -u -p -b -r1.14 program_representation_utils.m
--- deep_profiler/program_representation_utils.m 3 Oct 2008 07:37:24 -0000 1.14
+++ deep_profiler/program_representation_utils.m 7 Oct 2008 09:28:12 -0000
@@ -583,8 +583,6 @@ goal_annotate_coverage(Info, GoalPath, !
Goal0 = goal_rep(GoalExpr0, Detism, _),
% Calculate coverage of any inner goals.
- % XXX Why call propagate_detism_coverage only for cut scope goals and
- % atomic goals?
(
GoalExpr0 = conj_rep(Conjuncts0),
conj_annotate_coverage(Info, GoalPath, !Before, !After,
@@ -607,20 +605,13 @@ goal_annotate_coverage(Info, GoalPath, !
GoalExpr = ite_rep(Cond, Then, Else)
;
GoalExpr0 = negation_rep(NegGoal0),
- negation_annotate_coverage(Info, GoalPath, !Before, !After,
+ negation_annotate_coverage(Info, GoalPath, Detism, !Before, !After,
NegGoal0, NegGoal),
- propagate_detism_coverage(Detism, GoalPath, !Before, !After),
GoalExpr = negation_rep(NegGoal)
;
GoalExpr0 = scope_rep(ScopedGoal0, MaybeCut),
- scope_annotate_coverage(Info, GoalPath, MaybeCut, !Before, !After,
- ScopedGoal0, ScopedGoal),
- (
- MaybeCut = scope_is_cut,
- propagate_detism_coverage(Detism, GoalPath, !Before, !After)
- ;
- MaybeCut = scope_is_no_cut
- ),
+ scope_annotate_coverage(Info, GoalPath, MaybeCut, Detism,
+ !Before, !After, ScopedGoal0, ScopedGoal),
GoalExpr = scope_rep(ScopedGoal, MaybeCut)
;
GoalExpr0 = atomic_goal_rep(Filename, Line, Vars, AtomicGoal),
@@ -767,7 +758,9 @@ conj_annotate_coverage_2(Info, GoalPath,
disj_annotate_coverage(Info, Detism, GoalPath, !Before, !After,
Disjs0, Disjs) :-
% XXX In theory, we could update Before using information from any counter
- % at the start of the difirst disjunct, but we don't do that (yet).
+ % at the start of the first disjunct, but we don't do that (yet). This may
+ % not be useful for some disjunctions, for example those called from a
+ % single solution context or committed-choice.
CoverageBefore = !.Before,
Solutions = detism_get_solutions(Detism),
disj_annotate_coverage_2(Info, GoalPath, 1, Solutions,
@@ -939,10 +932,12 @@ ite_annotate_coverage(Info, GoalPath, !B
BeforeThen0 = before_unknown,
get_branch_start_coverage(Info, ThenGoalPath, BeforeThen1)
),
- % XXX It should be possible, if the condition is not at_most_many,
- % to compute BeforeElse as the difference between the counts in
- % the initial value of !.Before and AfterCond, if both are known.
- % check_ite_coverage already knows the relationship.
+ % XXX It should be possible, if the condition is not at_most_many and does
+ % not throw exceptions, to compute BeforeElse as the difference between the
+ % counts in the initial value of !.Before and AfterCond, if both are known.
+ % check_ite_coverage already knows the relationship. Using exception
+ % counts on call goals and propagating them through the coverage annotation
+ % algorithms can solve this.
get_branch_start_coverage(Info, ElseGoalPath, BeforeElse1),
trace [compile_time(flag("debug_coverage_propagation")), io(!IO)] (
@@ -1008,30 +1003,34 @@ get_branch_start_coverage(Info, GoalPath
).
:- pred negation_annotate_coverage(coverage_reference_info::in, goal_path::in,
- coverage_before::in, coverage_before::out,
+ detism_rep::in, coverage_before::in, coverage_before::out,
coverage_after::in, coverage_after::out,
goal_rep::in, goal_rep(coverage_info)::out) is det.
-negation_annotate_coverage(Info, GoalPath, !Before, !After,
+negation_annotate_coverage(Info, GoalPath, Detism, !Before, !After,
NegGoal0, NegGoal) :-
- % XXX We never update or even access !After.
NegGoalPath = goal_path_add_at_end(GoalPath, step_neg),
goal_annotate_coverage(Info, NegGoalPath,
!Before, after_unknown, _CoverageAfter, NegGoal0, NegGoal),
+ % Set the coverage after based on the coverage before and the determinism
+ % of the entire goal. There's no reason to update the coverage before this
+ % goal since it has already been applied to the inner goal.
+ propagate_detism_coverage(Detism, GoalPath, !.Before, _Before, !After),
trace [compile_time(flag("debug_coverage_propagation")), io(!IO)] (
io.format("Negation: setting negation: before %s, after %s\n",
[s(string(!.Before)), s(string(!.After))], !IO)
).
:- pred scope_annotate_coverage(coverage_reference_info::in,
- goal_path::in, maybe_cut::in,
+ goal_path::in, maybe_cut::in, detism_rep::in,
coverage_before::in, coverage_before::out,
coverage_after::in, coverage_after::out,
goal_rep::in, goal_rep(coverage_info)::out) is det.
-scope_annotate_coverage(Info, GoalPath, MaybeCut, !Before, !After,
+scope_annotate_coverage(Info, GoalPath, MaybeCut, Detism, !Before, !After,
ScopedGoal0, ScopedGoal) :-
ScopeGoalPath = goal_path_add_at_end(GoalPath, step_scope(MaybeCut)),
+ AfterScopeGoal = !.After,
(
MaybeCut = scope_is_cut,
AfterScopedGoal0 = after_unknown
@@ -1043,7 +1042,16 @@ scope_annotate_coverage(Info, GoalPath,
!Before, AfterScopedGoal0, AfterScopedGoal, ScopedGoal0, ScopedGoal),
(
MaybeCut = scope_is_cut,
- !:After = after_unknown
+ (
+ AfterScopeGoal = after_known(_),
+ !:After = AfterScopeGoal
+ ;
+ AfterScopeGoal = after_unknown,
+ % If coverage is unknown after the scoped goal try to infer it from
+ % the determinism of the goal.
+ propagate_detism_coverage(Detism, GoalPath, !.Before, _Before,
+ after_unknown, !:After)
+ )
;
MaybeCut = scope_is_no_cut,
!:After = AfterScopedGoal
@@ -1077,7 +1085,10 @@ detism_coverage_ok(Coverage, Detism) = O
OK = yes
;
Coverage = coverage_known(Entry, Exit),
- ( Entry = Exit ->
+ % Execution may leave via the Excp port rather than the exit port.
+ % so the exit port count may be smaller than or equal to the entry
+ % port count.
+ ( Entry >= Exit ->
OK = yes
;
OK = no
@@ -1119,12 +1130,10 @@ detism_coverage_ok(Coverage, Detism) = O
),
OK = yes
;
- Coverage = coverage_known(Entry, Exit),
- ( Entry =< Exit ->
+ Coverage = coverage_known(_Entry, _Exit),
+ % If the goal throws exceptions no inequalities can be used to
+ % check the correctness of the coverage information.
OK = yes
- ;
- OK = no
- )
)
;
Detism = nondet_rep,
@@ -1209,7 +1218,7 @@ sum_switch_case_coverage(case_rep(_, _,
detism_rep::in) is semidet.
check_ite_coverage(Before, After, BeforeCond, AfterCond,
- BeforeThen, AfterThen, BeforeElse, AfterElse, CondDetism) :-
+ BeforeThen, AfterThen, _BeforeElse, AfterElse, CondDetism) :-
(
Before = before_known(BeforeExecCount),
BeforeCond = before_known(BeforeCondExecCount)
@@ -1235,29 +1244,22 @@ check_ite_coverage(Before, After, Before
;
true
),
+ % Since the condition may throw exceptions and exception count information
+ % is not propagated checking the coverage before the else goal based on the
+ % coverage before and after the condition goal cannot be done.
+
+ ( AfterCond = after_known(AfterCondExecCount2) ->
NumSolutions = detism_get_solutions(CondDetism),
(
- ( NumSolutions = at_most_zero_rep
- ; NumSolutions = at_most_one_rep
- ),
- (
- BeforeCond = before_known(BeforeCondExecCount2),
- AfterCond = after_known(AfterCondExecCount2),
- BeforeElse = before_known(BeforeElseExecCount)
- ->
- BeforeElseExecCount = BeforeCondExecCount2 - AfterCondExecCount2,
- (
NumSolutions = at_most_zero_rep,
AfterCondExecCount2 = 0
;
- NumSolutions = at_most_one_rep
+ ( NumSolutions = at_most_one_rep
+ ; NumSolutions = at_most_many_rep
)
- ;
- true
)
;
- NumSolutions = at_most_many_rep
- % There is no relationship we can check here.
+ true
).
:- pred check_coverage_complete(coverage_info::in, goal_expr_rep(T)::in)
@@ -1364,6 +1366,10 @@ propagate_det_coverage(GoalPath, !Before
% If the determinism is deterministic or cc_multi use
% propagate_det_coverage.
%
+ % Note: This predicate must not be called on deterministic call goals,
+ % since the coverage after the call may be different to the coverage before
+ % if the called code throws an exception.
+ %
:- pred propagate_detism_coverage(detism_rep::in, goal_path::in,
coverage_before::in, coverage_before::out,
coverage_after::in, coverage_after::out) is det.
@@ -1371,10 +1377,10 @@ propagate_det_coverage(GoalPath, !Before
propagate_detism_coverage(Detism, GoalPath, !Before, !After) :-
% TODO: Infer that if a goal has a coverage of exactly 0 before it, then it
% must have a coverage of exactly 0 after it. And that a goal that cannot
- % fail that has a coverage of 0 after it, must have a coverage of 0 before
- % it - Since the coverage profiling and propagation algorithms are already
- % complete this isn't required. It should be considered if we choose not
- % to calculate coverage for trivial goals.
+ % fail or throw an exception that has a coverage of 0 after it, must have a
+ % coverage of 0 before it - Since the coverage profiling and propagation
+ % algorithms are already complete this isn't required. It should be
+ % considered if we choose not to calculate coverage for trivial goals.
(
( Detism = det_rep
; Detism = cc_multidet_rep
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