On Fri, 2019-11-15 at 20:22 -0500, David Malcolm wrote:
> This patch adds support for associating a "diagnostic_path" with a
> diagnostic: a sequence of events predicted by the compiler that leads
> to
> the problem occurring, with their locations in the user's source,
> text descriptions, and stack information (for handling
> interprocedural
> paths).
>
> For example, the following (hypothetical) error has a 3-event
> intraprocedural path:
>
> test.c: In function 'demo':
> test.c:29:5: error: passing NULL as argument 1 to 'PyList_Append'
> which
> requires a non-NULL parameter
> 29 | PyList_Append(list, item);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~
> 'demo': events 1-3
> |
> | 25 | list = PyList_New(0);
> | | ^~~~~~~~~~~~~
> | | |
> | | (1) when 'PyList_New' fails, returning NULL
> | 26 |
> | 27 | for (i = 0; i < count; i++) {
> | | ~~~
> | | |
> | | (2) when 'i < count'
> | 28 | item = PyLong_FromLong(random());
> | 29 | PyList_Append(list, item);
> | | ~~~~~~~~~~~~~~~~~~~~~~~~~
> | | |
> | | (3) when calling 'PyList_Append', passing NULL from
> (1) as argument 1
> |
>
> The patch adds a new "%@" format code for printing event IDs, so that
> in the above, the description of event (3) mentions event (1),
> showing
> the user where the bogus NULL value comes from (the event IDs are
> colorized to draw the user's attention to them).
>
> There is a separation between data vs presentation: the above shows
> how
> the diagnostic-printing code has consolidated the path into a single
> run
> of events, since all the events are near each other and within the
> same
> function; more complicated examples (such as interprocedural paths)
> might be printed as multiple runs of events.
>
> Examples of how interprocedural paths are printed can be seen in the
> test suite (which uses a plugin to exercise the code without relying
> on specific warnings using this functionality).
>
> Other output formats include
> - JSON,
> - printing each event as a separate "note", and
> - to not emit paths.
>
> (I have a separate script that can generate HTML from the JSON, but
> HTML
> is not my speciality; help from a web front-end expert to make it
> look
> good would be appreciated).
>
> gcc/ChangeLog:
> * Makefile.in (OBJS): Add tree-diagnostic-path.o.
> * common.opt (fdiagnostics-path-format=): New option.
> (diagnostic_path_format): New enum.
> (fdiagnostics-show-path-depths): New option.
> * coretypes.h (diagnostic_event_id_t): New forward decl.
> * diagnostic-color.c (color_dict): Add "path".
> * diagnostic-event-id.h: New file.
> * diagnostic-format-json.cc (json_from_expanded_location): Make
> non-static.
> (json_end_diagnostic): Call context->make_json_for_path if it
> exists and the diagnostic has a path.
> (diagnostic_output_format_init): Clear context->print_path.
> * diagnostic-path.h: New file.
> * diagnostic-show-locus.c (colorizer::set_range): Special-case
> when printing a run of events in a diagnostic_path so that they
> all get the same color.
> (layout::m_diagnostic_path_p): New field.
> (layout::layout): Initialize it.
> (layout::print_any_labels): Don't colorize the label text for
> an
> event in a diagnostic_path.
> (gcc_rich_location::add_location_if_nearby): Add
> "restrict_to_current_line_spans" and "label" params. Pass the
> former to layout.maybe_add_location_range; pass the latter
> when calling add_range.
> * diagnostic.c: Include "diagnostic-path.h".
> (diagnostic_initialize): Initialize context->path_format and
> context->show_path_depths.
> (diagnostic_show_any_path): New function.
> (diagnostic_path::interprocedural_p): New function.
> (diagnostic_report_diagnostic): Call diagnostic_show_any_path.
> (simple_diagnostic_path::num_events): New function.
> (simple_diagnostic_path::get_event): New function.
> (simple_diagnostic_path::add_event): New function.
> (simple_diagnostic_event::simple_diagnostic_event): New ctor.
> (simple_diagnostic_event::~simple_diagnostic_event): New dtor.
> (debug): New overload taking a diagnostic_path *.
> * diagnostic.def (DK_DIAGNOSTIC_PATH): New.
> * diagnostic.h (enum diagnostic_path_format): New enum.
> (json::value): New forward decl.
> (diagnostic_context::path_format): New field.
> (diagnostic_context::show_path_depths): New field.
> (diagnostic_context::print_path): New callback field.
> (diagnostic_context::make_json_for_path): New callback field.
> (diagnostic_show_any_path): New decl.
> (json_from_expanded_location): New decl.
> * doc/invoke.texi (-fdiagnostics-path-format=): New option.
> (-fdiagnostics-show-path-depths): New option.
> (-fdiagnostics-color): Add "path" to description of default
> GCC_COLORS; describe it.
> (-fdiagnostics-format=json): Document how diagnostic paths are
> represented in the JSON output format.
> * gcc-rich-location.h
> (gcc_rich_location::add_location_if_nearby):
> Add optional params "restrict_to_current_line_spans" and
> "label".
> * opts.c (common_handle_option): Handle
> OPT_fdiagnostics_path_format_ and
> OPT_fdiagnostics_show_path_depths.
> * pretty-print.c: Include "diagnostic-event-id.h".
> (pp_format): Implement "%@" format code for printing
> diagnostic_event_id_t *.
> (selftest::test_pp_format): Add tests for "%@".
> * selftest-run-tests.c (selftest::run_tests): Call
> selftest::tree_diagnostic_path_cc_tests.
> * selftest.h (selftest::tree_diagnostic_path_cc_tests): New
> decl.
> * toplev.c (general_init): Initialize global_dc->path_format
> and
> global_dc->show_path_depths.
> * tree-diagnostic-path.cc: New file.
> * tree-diagnostic.c (maybe_unwind_expanded_macro_loc): Make
> non-static. Drop "diagnostic" param in favor of storing the
> original value of "where" and re-using it.
> (virt_loc_aware_diagnostic_finalizer): Update for dropped param
> of
> maybe_unwind_expanded_macro_loc.
> (tree_diagnostics_defaults): Initialize context->print_path and
> context->make_json_for_path.
> * tree-diagnostic.h (default_tree_diagnostic_path_printer): New
> decl.
> (default_tree_make_json_for_path): New decl.
> (maybe_unwind_expanded_macro_loc): New decl.
>
> gcc/c-family/ChangeLog:
> * c-format.c (local_event_ptr_node): New.
> (PP_FORMAT_CHAR_TABLE): Add entry for "%@".
> (init_dynamic_diag_info): Initialize local_event_ptr_node.
> * c-format.h (T_EVENT_PTR): New define.
>
> gcc/testsuite/ChangeLog:
> * gcc.dg/format/gcc_diag-10.c (diagnostic_event_id_t): New
> typedef.
> (test_diag): Add coverage of "%@".
> * gcc.dg/plugin/diagnostic-path-format-default.c: New test.
> * gcc.dg/plugin/diagnostic-path-format-inline-events-1.c: New
> test.
> * gcc.dg/plugin/diagnostic-path-format-inline-events-2.c: New
> test.
> * gcc.dg/plugin/diagnostic-path-format-inline-events-3.c: New
> test.
> * gcc.dg/plugin/diagnostic-path-format-none.c: New test.
> * gcc.dg/plugin/diagnostic-test-paths-1.c: New test.
> * gcc.dg/plugin/diagnostic-test-paths-2.c: New test.
> * gcc.dg/plugin/diagnostic-test-paths-3.c: New test.
> * gcc.dg/plugin/diagnostic_plugin_test_paths.c: New.
> * gcc.dg/plugin/plugin.exp: Add the new plugin and test cases.
>
> libcpp/ChangeLog:
> * include/line-map.h (class diagnostic_path): New forward decl.
> (rich_location::get_path): New accessor.
> (rich_location::set_path): New function.
> (rich_location::m_path): New field.
> * line-map.c (rich_location::rich_location): Initialize m_path.
Seems like we could make an argument to include this in an expanded
"diagnostic framework" maintainership which would allow self-approval.
jeff
