diagnostics: support multithreaded diagnostic paths

This patch extends the existing diagnostic_path class so that as well
as list of events, there is a list of named threads, with each event
being associated with one of the threads.

No GCC diagnostics take advantage of this, but GCC plugins may find a
use for this; an example is provided in the testsuite.

Given that there is still a single list of events within a
diagnostic_path, the events in a diagnostic_path have a specific global
ordering even if they are in multiple threads.

Within the SARIF serialization, the patch adds the "executionOrder"
property to threadFlowLocation objects (SARIF v2.1.0 3.38.11).  This is
1-based in order to match the human-readable numbering of events shown
in messages emitted by pretty-printer.cc's "%@".

With -fdiagnostics-path-format=separate-events, the threads are not
shown.

With -fdiagnostics-path-format=inline-events, the threads and the
per-thread stack activity are tracked and visalized separately.  An
example can be seen in the testsuite.

gcc/analyzer/ChangeLog:
	* checker-event.h (checker_event::get_thread_id): New.
	* checker-path.h (class checker_path): Implement thread-related
	vfuncs via a single simple_diagnostic_thread instance named
	"main".

gcc/ChangeLog:
	* diagnostic-event-id.h (diagnostic_thread_id_t): New typedef.
	* diagnostic-format-sarif.cc (class sarif_thread_flow): New.
	(sarif_thread_flow::sarif_thread_flow): New.
	(sarif_builder::make_code_flow_object): Reimplement, creating
	per-thread threadFlow objects, populating them with the relevant
	events.
	(sarif_builder::make_thread_flow_object): Delete, moving the
	code into sarif_builder::make_code_flow_object.
	(sarif_builder::make_thread_flow_location_object): Add
	"path_event_idx" param.  Use it to set "executionOrder"
	property.
	* diagnostic-path.h (diagnostic_event::get_thread_id): New
	pure-virtual vfunc.
	(class diagnostic_thread): New.
	(diagnostic_path::num_threads): New pure-virtual vfunc.
	(diagnostic_path::get_thread):  New pure-virtual vfunc.
	(diagnostic_path::multithreaded_p): New decl.
	(simple_diagnostic_event::simple_diagnostic_event): Add optional
	thread_id param.
	(simple_diagnostic_event::get_thread_id): New accessor.
	(simple_diagnostic_event::m_thread_id): New.
	(class simple_diagnostic_thread): New.
	(simple_diagnostic_path::simple_diagnostic_path): Move definition
	to diagnostic.cc.
	(simple_diagnostic_path::num_threads): New.
	(simple_diagnostic_path::get_thread): New.
	(simple_diagnostic_path::add_thread): New.
	(simple_diagnostic_path::add_thread_event): New.
	(simple_diagnostic_path::m_threads): New.
	* diagnostic-show-locus.cc (layout::layout): Add pretty_printer
	param for overriding the context's printer.
	(diagnostic_show_locus): Likwise.
	* diagnostic.cc (simple_diagnostic_path::simple_diagnostic_path):
	Move here from diagnostic-path.h.  Add main thread.
	(simple_diagnostic_path::num_threads): New.
	(simple_diagnostic_path::get_thread): New.
	(simple_diagnostic_path::add_thread): New.
	(simple_diagnostic_path::add_thread_event): New.
	(simple_diagnostic_event::simple_diagnostic_event): Add thread_id
	param and use it to initialize m_thread_id.  Reformat.
	* diagnostic.h: Add pretty_printer param for overriding the
	context's printer.
	* tree-diagnostic-path.cc: Add #define INCLUDE_VECTOR.
	(can_consolidate_events): Compare thread ids.
	(class per_thread_summary): New.
	(event_range::event_range): Add per_thread_summary arg.
	(event_range::print): Add "pp" param and use it rather than dc's
	printer.
	(event_range::m_thread_id): New field.
	(event_range::m_per_thread_summary): New field.
	(path_summary::multithreaded_p): New.
	(path_summary::get_events_for_thread_id): New.
	(path_summary::m_per_thread_summary): New field.
	(path_summary::m_thread_id_to_events): New field.
	(path_summary::get_or_create_events_for_thread_id): New.
	(path_summary::path_summary): Create per_thread_summary instances
	as needed and associate the event_range instances with them.
	(base_indent): Move here from print_path_summary_as_text.
	(per_frame_indent): Likewise.
	(class thread_event_printer): New, adapted from parts of
	print_path_summary_as_text.
	(print_path_summary_as_text): Make static.  Reimplement to
	moving most of existing code to class thread_event_printer,
	capturing state as per-thread as appropriate.
	(default_tree_diagnostic_path_printer): Add missing 'break' on
	final case.

gcc/testsuite/ChangeLog:
	* gcc.dg/plugin/diagnostic-test-paths-multithreaded-inline-events.c:
	New test.
	* gcc.dg/plugin/diagnostic-test-paths-multithreaded-sarif.c: New
	test.
	* gcc.dg/plugin/diagnostic-test-paths-multithreaded-separate-events.c:
	New test.
	* gcc.dg/plugin/diagnostic_plugin_test_paths.c: Add support for
	generating multithreaded paths.
	* gcc.dg/plugin/plugin.exp: Add the new tests.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

2 files changed, 20 insertions, 1 deletions

diff --git a/gcc/analyzer/checker-event.h b/gcc/analyzer/checker-event.h
index 5dd25cb..7ba92f1 100644
--- a/gcc/analyzer/checker-event.h
+++ b/gcc/analyzer/checker-event.h
@@ -113,6 +113,10 @@ public:
       return NULL;
   }
   meaning get_meaning () const override;
+  diagnostic_thread_id_t get_thread_id () const final override
+  {
+    return 0;
+  }
 
   /* Additional functionality.  */
 
diff --git a/gcc/analyzer/checker-path.h b/gcc/analyzer/checker-path.h
index 627f64e..93c807c 100644
--- a/gcc/analyzer/checker-path.h
+++ b/gcc/analyzer/checker-path.h
@@ -30,7 +30,11 @@ namespace ana {
 class checker_path : public diagnostic_path
 {
 public:
-  checker_path (logger *logger) : diagnostic_path (), m_logger (logger) {}
+  checker_path (logger *logger)
+  : diagnostic_path (),
+    m_thread ("main"),
+    m_logger (logger)
+  {}
 
   /* Implementation of diagnostic_path vfuncs.  */
 
@@ -43,6 +47,15 @@ public:
   {
     return *m_events[idx];
   }
+  unsigned num_threads () const final override
+  {
+    return 1;
+  }
+  const diagnostic_thread &
+  get_thread (diagnostic_thread_id_t) const final override
+  {
+    return m_thread;
+  }
 
   checker_event *get_checker_event (int idx)
   {
@@ -120,6 +133,8 @@ public:
 private:
   DISABLE_COPY_AND_ASSIGN(checker_path);
 
+  simple_diagnostic_thread m_thread;
+
   /* The events that have occurred along this path.  */
   auto_delete_vec<checker_event> m_events;