Re: [PATCH v10 1/2] Add condition coverage (MC/DC)

["H.J. Lu" <hjl.tools@gmail.com>]

On Thu, Apr 4, 2024 at 5:54 AM Jørgen Kvalsvik <j@lambda.is> wrote:
>
> On 04/04/2024 14:10, Jan Hubicka wrote:
> >> gcc/ChangeLog:
> >>
> >>      * builtins.cc (expand_builtin_fork_or_exec): Check
> >>        condition_coverage_flag.
> >>      * collect2.cc (main): Add -fno-condition-coverage to OBSTACK.
> >>      * common.opt: Add new options -fcondition-coverage and
> >>        -Wcoverage-too-many-conditions.
> >>      * doc/gcov.texi: Add --conditions documentation.
> >>      * doc/invoke.texi: Add -fcondition-coverage documentation.
> >>      * function.cc (free_after_compilation): Free cond_uids.
> >>      * function.h (struct function): Add cond_uids.
> >>      * gcc.cc: Link gcov on -fcondition-coverage.
> >>      * gcov-counter.def (GCOV_COUNTER_CONDS): New.
> >>      * gcov-dump.cc (tag_conditions): New.
> >>      * gcov-io.h (GCOV_TAG_CONDS): New.
> >>      (GCOV_TAG_CONDS_LENGTH): New.
> >>      (GCOV_TAG_CONDS_NUM): New.
> >>      * gcov.cc (class condition_info): New.
> >>      (condition_info::condition_info): New.
> >>      (condition_info::popcount): New.
> >>      (struct coverage_info): New.
> >>      (add_condition_counts): New.
> >>      (output_conditions): New.
> >>      (print_usage): Add -g, --conditions.
> >>      (process_args): Likewise.
> >>      (output_intermediate_json_line): Output conditions.
> >>      (read_graph_file): Read condition counters.
> >>      (read_count_file): Likewise.
> >>      (file_summary): Print conditions.
> >>      (accumulate_line_info): Accumulate conditions.
> >>      (output_line_details): Print conditions.
> >>      * gimplify.cc (next_cond_uid): New.
> >>      (reset_cond_uid): New.
> >>      (shortcut_cond_r): Set condition discriminator.
> >>      (tag_shortcut_cond): New.
> >>      (gimple_associate_condition_with_expr): New.
> >>      (shortcut_cond_expr): Set condition discriminator.
> >>      (gimplify_cond_expr): Likewise.
> >>      (gimplify_function_tree): Call reset_cond_uid.
> >>      * ipa-inline.cc (can_early_inline_edge_p): Check
> >>        condition_coverage_flag.
> >>      * ipa-split.cc (pass_split_functions::gate): Likewise.
> >>      * passes.cc (finish_optimization_passes): Likewise.
> >>      * profile.cc (struct condcov): New declaration.
> >>      (cov_length): Likewise.
> >>      (cov_blocks): Likewise.
> >>      (cov_masks): Likewise.
> >>      (cov_maps): Likewise.
> >>      (cov_free): Likewise.
> >>      (instrument_decisions): New.
> >>      (read_thunk_profile): Control output to file.
> >>      (branch_prob): Call find_conditions, instrument_decisions.
> >>      (init_branch_prob): Add total_num_conds.
> >>      (end_branch_prob): Likewise.
> >>      * tree-core.h (struct tree_exp): Add condition_uid.
> >>      * tree-profile.cc (struct conds_ctx): New.
> >>      (CONDITIONS_MAX_TERMS): New.
> >>      (EDGE_CONDITION): New.
> >>      (topological_cmp): New.
> >>      (index_of): New.
> >>      (single_p): New.
> >>      (single_edge): New.
> >>      (contract_edge_up): New.
> >>      (struct outcomes): New.
> >>      (conditional_succs): New.
> >>      (condition_index): New.
> >>      (condition_uid): New.
> >>      (masking_vectors): New.
> >>      (emit_assign): New.
> >>      (emit_bitwise_op): New.
> >>      (make_top_index_visit): New.
> >>      (make_top_index): New.
> >>      (paths_between): New.
> >>      (struct condcov): New.
> >>      (cov_length): New.
> >>      (cov_blocks): New.
> >>      (cov_masks): New.
> >>      (cov_maps): New.
> >>      (cov_free): New.
> >>      (find_conditions): New.
> >>      (struct counters): New.
> >>      (find_counters): New.
> >>      (resolve_counter): New.
> >>      (resolve_counters): New.
> >>      (instrument_decisions): New.
> >>      (tree_profiling): Check condition_coverage_flag.
> >>      (pass_ipa_tree_profile::gate): Likewise.
> >>      * tree.h (SET_EXPR_UID): New.
> >>      (EXPR_COND_UID): New.
> >>
> >> libgcc/ChangeLog:
> >>
> >>      * libgcov-merge.c (__gcov_merge_ior): New.
> >>
> >> gcc/testsuite/ChangeLog:
> >>
> >>      * lib/gcov.exp: Add condition coverage test function.
> >>      * g++.dg/gcov/gcov-18.C: New test.
> >>      * gcc.misc-tests/gcov-19.c: New test.
> >>      * gcc.misc-tests/gcov-20.c: New test.
> >>      * gcc.misc-tests/gcov-21.c: New test.
> >>      * gcc.misc-tests/gcov-22.c: New test.
> >>      * gcc.misc-tests/gcov-23.c: New test.
> >> ---
> >>   gcc/builtins.cc                        |    2 +-
> >>   gcc/collect2.cc                        |    7 +-
> >>   gcc/common.opt                         |    9 +
> >>   gcc/doc/gcov.texi                      |   38 +
> >>   gcc/doc/invoke.texi                    |   21 +
> >>   gcc/function.cc                        |    1 +
> >>   gcc/function.h                         |    4 +
> >>   gcc/gcc.cc                             |    4 +-
> >>   gcc/gcov-counter.def                   |    3 +
> >>   gcc/gcov-dump.cc                       |   24 +
> >>   gcc/gcov-io.h                          |    3 +
> >>   gcc/gcov.cc                            |  209 ++-
> >>   gcc/gimplify.cc                        |  123 +-
> >>   gcc/ipa-inline.cc                      |    2 +-
> >>   gcc/ipa-split.cc                       |    2 +-
> >>   gcc/passes.cc                          |    3 +-
> >>   gcc/profile.cc                         |   76 +-
> >>   gcc/testsuite/g++.dg/gcov/gcov-18.C    |  282 ++++
> >>   gcc/testsuite/gcc.misc-tests/gcov-19.c | 1737 ++++++++++++++++++++++++
> >>   gcc/testsuite/gcc.misc-tests/gcov-20.c |   22 +
> >>   gcc/testsuite/gcc.misc-tests/gcov-21.c |   16 +
> >>   gcc/testsuite/gcc.misc-tests/gcov-22.c |  103 ++
> >>   gcc/testsuite/gcc.misc-tests/gcov-23.c |  361 +++++
> >>   gcc/testsuite/lib/gcov.exp             |  259 +++-
> >>   gcc/tree-core.h                        |    3 +
> >>   gcc/tree-profile.cc                    | 1058 ++++++++++++++-
> >>   gcc/tree.h                             |    4 +
> >>   libgcc/libgcov-merge.c                 |    5 +
> >>   28 files changed, 4339 insertions(+), 42 deletions(-)
> >>   create mode 100644 gcc/testsuite/g++.dg/gcov/gcov-18.C
> >>   create mode 100644 gcc/testsuite/gcc.misc-tests/gcov-19.c
> >>   create mode 100644 gcc/testsuite/gcc.misc-tests/gcov-20.c
> >>   create mode 100644 gcc/testsuite/gcc.misc-tests/gcov-21.c
> >>   create mode 100644 gcc/testsuite/gcc.misc-tests/gcov-22.c
> >>   create mode 100644 gcc/testsuite/gcc.misc-tests/gcov-23.c
> >>
> >> ---
> >> Changes since v9:
> >>
> >> * function->cond_uid is no longer in ggc memory
> >> * function->cond_uid and condition annotation is only done when coverage
> >>    is requested
> >> * A few new test cases, notably interactions with C++ constexpr
> >> * Updated comments based on review feedback
> >> ---
> >>
> >
> >> diff --git a/gcc/ipa-inline.cc b/gcc/ipa-inline.cc
> >> index dc120e6da5a..9502a21c741 100644
> >> --- a/gcc/ipa-inline.cc
> >> +++ b/gcc/ipa-inline.cc
> >> @@ -682,7 +682,7 @@ can_early_inline_edge_p (struct cgraph_edge *e)
> >>       }
> >>     gcc_assert (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->caller->decl))
> >>            && gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)));
> >> -  if (profile_arc_flag
> >> +  if ((profile_arc_flag || condition_coverage_flag)
> >>         && ((lookup_attribute ("no_profile_instrument_function",
> >>                          DECL_ATTRIBUTES (caller->decl)) == NULL_TREE)
> >>        != (lookup_attribute ("no_profile_instrument_function",
> >
> > tree-inline should also copy the cond tags, since always_inline
> > functions are inlined even at -O0.  But I think this can be done
> > incrementally.
> >
> > Patch is OK.
> > Thanks a lot and sorry for taking so long on this one.
> > Honza
>
> I guess you mean that since tree-inlining happen after gimplification
> (does it?) that the basic condition -> condition expression association
> should also fold in the now-inlined conditions?
>
> Thanks for the review - I'll do a final test run and install the patch.

The new -fcondition-coverage segfaults:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114599#c5

-- 
H.J.