analyzer: early rejection of disabled warnings [PR104955]

Avoid generating execution paths for warnings that are ultimately
rejected due to -Wno-analyzer-* flags.

This improves the test case from taking at least several minutes
(before I killed it) to taking under a second.

This doesn't fix the slowdown seen in PR analyzer/104955 with large
numbers of warnings when the warnings are still enabled.

gcc/analyzer/ChangeLog:
	PR analyzer/104955
	* diagnostic-manager.cc (get_emission_location): New.
	(diagnostic_manager::diagnostic_manager): Initialize
	m_num_disabled_diagnostics.
	(diagnostic_manager::add_diagnostic): Reject diagnostics that
	will eventually be rejected due to being disabled.
	(diagnostic_manager::emit_saved_diagnostics): Log the number
	of disabled diagnostics.
	(diagnostic_manager::emit_saved_diagnostic): Split out logic for
	determining emission location to get_emission_location.
	* diagnostic-manager.h
	(diagnostic_manager::m_num_disabled_diagnostics): New field.
	* engine.cc (stale_jmp_buf::get_controlling_option): New.
	(stale_jmp_buf::emit): Use it.
	* pending-diagnostic.h
	(pending_diagnostic::get_controlling_option): New vfunc.
	* region-model.cc
	(poisoned_value_diagnostic::get_controlling_option): New.
	(poisoned_value_diagnostic::emit): Use it.
	(shift_count_negative_diagnostic::get_controlling_option): New.
	(shift_count_negative_diagnostic::emit): Use it.
	(shift_count_overflow_diagnostic::get_controlling_option): New.
	(shift_count_overflow_diagnostic::emit): Use it.
	(dump_path_diagnostic::get_controlling_option): New.
	(dump_path_diagnostic::emit): Use it.
	(write_to_const_diagnostic::get_controlling_option): New.
	(write_to_const_diagnostic::emit): Use it.
	(write_to_string_literal_diagnostic::get_controlling_option): New.
	(write_to_string_literal_diagnostic::emit): Use it.
	* sm-file.cc (double_fclose::get_controlling_option): New.
	(double_fclose::emit): Use it.
	(file_leak::get_controlling_option): New.
	(file_leak::emit): Use it.
	* sm-malloc.cc (mismatching_deallocation::get_controlling_option):
	New.
	(mismatching_deallocation::emit): Use it.
	(double_free::get_controlling_option): New.
	(double_free::emit): Use it.
	(possible_null_deref::get_controlling_option): New.
	(possible_null_deref::emit): Use it.
	(possible_null_arg::get_controlling_option): New.
	(possible_null_arg::emit): Use it.
	(null_deref::get_controlling_option): New.
	(null_deref::emit): Use it.
	(null_arg::get_controlling_option): New.
	(null_arg::emit): Use it.
	(use_after_free::get_controlling_option): New.
	(use_after_free::emit): Use it.
	(malloc_leak::get_controlling_option): New.
	(malloc_leak::emit): Use it.
	(free_of_non_heap::get_controlling_option): New.
	(free_of_non_heap::emit): Use it.
	* sm-pattern-test.cc (pattern_match::get_controlling_option): New.
	(pattern_match::emit): Use it.
	* sm-sensitive.cc
	(exposure_through_output_file::get_controlling_option): New.
	(exposure_through_output_file::emit): Use it.
	* sm-signal.cc (signal_unsafe_call::get_controlling_option): New.
	(signal_unsafe_call::emit): Use it.
	* sm-taint.cc (tainted_array_index::get_controlling_option): New.
	(tainted_array_index::emit): Use it.
	(tainted_offset::get_controlling_option): New.
	(tainted_offset::emit): Use it.
	(tainted_size::get_controlling_option): New.
	(tainted_size::emit): Use it.
	(tainted_divisor::get_controlling_option): New.
	(tainted_divisor::emit): Use it.
	(tainted_allocation_size::get_controlling_option): New.
	(tainted_allocation_size::emit): Use it.

gcc/testsuite/ChangeLog:
	* gcc.dg/analyzer/many-disabled-diagnostics.c: New test.
	* gcc.dg/plugin/analyzer_gil_plugin.c
	(gil_diagnostic::get_controlling_option): New.
	(double_save_thread::emit): Use it.
	(fncall_without_gil::emit): Likewise.
	(pyobject_usage_without_gil::emit): Likewise.

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

1 files changed, 39 insertions, 5 deletions

diff --git a/gcc/analyzer/diagnostic-manager.cc b/gcc/analyzer/diagnostic-manager.cc
index 561bb18cee0..d5e5b6926cc 100644
--- a/gcc/analyzer/diagnostic-manager.cc
+++ b/gcc/analyzer/diagnostic-manager.cc
@@ -849,13 +849,28 @@ private:
   const feasibility_problem *m_feasibility_problem;
 };
 
+/* Determine the emission location for PD at STMT in FUN.  */
+
+static location_t
+get_emission_location (const gimple *stmt, function *fun,
+		       const pending_diagnostic &pd)
+{
+  location_t loc = get_stmt_location (stmt, fun);
+
+  /* Allow the pending_diagnostic to fix up the location.  */
+  loc = pd.fixup_location (loc);
+
+  return loc;
+}
+
 /* class diagnostic_manager.  */
 
 /* diagnostic_manager's ctor.  */
 
 diagnostic_manager::diagnostic_manager (logger *logger, engine *eng,
 					int verbosity)
-: log_user (logger), m_eng (eng), m_verbosity (verbosity)
+: log_user (logger), m_eng (eng), m_verbosity (verbosity),
+  m_num_disabled_diagnostics (0)
 {
 }
 
@@ -877,6 +892,25 @@ diagnostic_manager::add_diagnostic (const state_machine *sm,
      through the exploded_graph to the diagnostic.  */
   gcc_assert (enode);
 
+  /* If this warning is ultimately going to be rejected by a -Wno-analyzer-*
+     flag, reject it now.
+     We can only do this for diagnostics where we already know the stmt,
+     and thus can determine the emission location.  */
+  if (stmt)
+    {
+      location_t loc = get_emission_location (stmt, snode->m_fun, *d);
+      int option = d->get_controlling_option ();
+      if (!warning_enabled_at (loc, option))
+	{
+	  if (get_logger ())
+	    get_logger ()->log ("rejecting disabled warning %qs",
+				d->get_kind ());
+	  delete d;
+	  m_num_disabled_diagnostics++;
+	  return;
+	}
+    }
+
   saved_diagnostic *sd
     = new saved_diagnostic (sm, enode, snode, stmt, finder, var, sval,
 			    state, d, m_saved_diagnostics.length ());
@@ -1186,6 +1220,7 @@ diagnostic_manager::emit_saved_diagnostics (const exploded_graph &eg)
   LOG_SCOPE (get_logger ());
   auto_timevar tv (TV_ANALYZER_DIAGNOSTICS);
   log ("# saved diagnostics: %i", m_saved_diagnostics.length ());
+  log ("# disabled diagnostics: %i", m_num_disabled_diagnostics);
   if (get_logger ())
     {
       unsigned i;
@@ -1265,11 +1300,10 @@ diagnostic_manager::emit_saved_diagnostic (const exploded_graph &eg,
 
   emission_path.prepare_for_emission (sd.m_d);
 
-  location_t loc = get_stmt_location (sd.m_stmt, sd.m_snode->m_fun);
+  location_t loc
+    = get_emission_location (sd.m_stmt, sd.m_snode->m_fun, *sd.m_d);
 
-  /* Allow the pending_diagnostic to fix up the primary location
-     and any locations for events.  */
-  loc = sd.m_d->fixup_location (loc);
+  /* Allow the pending_diagnostic to fix up the locations of events.  */
   emission_path.fixup_locations (sd.m_d);
 
   gcc_rich_location rich_loc (loc);