public inbox for gcc-patches@gcc.gnu.org
 help / color / mirror / Atom feed
* [PATCH] analyzer: New option fanalyzer-show-events-in-system-headers [PR110543]
@ 2023-08-11 11:51 priour.be
  2023-08-11 15:38 ` David Malcolm
  0 siblings, 1 reply; 4+ messages in thread
From: priour.be @ 2023-08-11 11:51 UTC (permalink / raw)
  To: gcc-patches; +Cc: dmalcolm, benjamin priour

From: benjamin priour <vultkayn@gcc.gnu.org>

This patch introduces -fanalyzer-show-events-in-system-headers,
disabled by default.

This option reduce the noise of the analyzer emitted diagnostics
when dealing with system headers.
The new option only affects the display of the diagnostics,
but doesn't hinder the actual analysis.

Given a diagnostics path diving into a system header in the form
[
  prefix events...,
  system header call,
    system header entry,
    events within system headers...,
  system header return,
  suffix events...
]
then disabling the option (either by default or explicitly)
will shorten the path into:
[
  prefix events...,
  system header call,
  system header return,
  suffix events...
]

Signed-off-by: benjamin priour <priour.be@gmail.com>

gcc/analyzer/ChangeLog:

	PR analyzer/110543
	* analyzer.cc (is_std_function_p): No longer static.
	* analyzer.h (is_std_function_p): Add declaration.
	* analyzer.opt: Add new option.
	* diagnostic-manager.cc
	(INCLUDE_VECTOR): Include vector from system.h
	(diagnostic_manager::prune_path): Call prune_system_headers.
	(prune_frame): New function that deletes all events in a frame.
	(diagnostic_manager::prune_system_headers): New function.
	* diagnostic-manager.h: Add prune_system_headers declaration.

gcc/testsuite/ChangeLog:

	PR analyzer/110543
	* g++.dg/analyzer/fanalyzer-show-events-in-system-headers-default.C:
	New test.
	* g++.dg/analyzer/fanalyzer-show-events-in-system-headers-no.C:
	New test.
---
 gcc/analyzer/analyzer.cc                      |  2 +-
 gcc/analyzer/analyzer.h                       |  1 +
 gcc/analyzer/analyzer.opt                     |  4 ++
 gcc/analyzer/diagnostic-manager.cc            | 65 +++++++++++++++++++
 gcc/analyzer/diagnostic-manager.h             |  1 +
 ...er-show-events-in-system-headers-default.C | 19 ++++++
 ...nalyzer-show-events-in-system-headers-no.C | 19 ++++++
 7 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-default.C
 create mode 100644 gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-no.C

diff --git a/gcc/analyzer/analyzer.cc b/gcc/analyzer/analyzer.cc
index 5091fb7a583..b27d8e359db 100644
--- a/gcc/analyzer/analyzer.cc
+++ b/gcc/analyzer/analyzer.cc
@@ -274,7 +274,7 @@ is_named_call_p (const_tree fndecl, const char *funcname)
    Compare with cp/typeck.cc: decl_in_std_namespace_p, but this doesn't
    rely on being the C++ FE (or handle inline namespaces inside of std).  */
 
-static inline bool
+bool
 is_std_function_p (const_tree fndecl)
 {
   tree name_decl = DECL_NAME (fndecl);
diff --git a/gcc/analyzer/analyzer.h b/gcc/analyzer/analyzer.h
index 579517c23e6..31597079153 100644
--- a/gcc/analyzer/analyzer.h
+++ b/gcc/analyzer/analyzer.h
@@ -386,6 +386,7 @@ extern bool is_special_named_call_p (const gcall *call, const char *funcname,
 extern bool is_named_call_p (const_tree fndecl, const char *funcname);
 extern bool is_named_call_p (const_tree fndecl, const char *funcname,
 			     const gcall *call, unsigned int num_args);
+extern bool is_std_function_p (const_tree fndecl);
 extern bool is_std_named_call_p (const_tree fndecl, const char *funcname);
 extern bool is_std_named_call_p (const_tree fndecl, const char *funcname,
 				 const gcall *call, unsigned int num_args);
diff --git a/gcc/analyzer/analyzer.opt b/gcc/analyzer/analyzer.opt
index 2760aaa8151..d97cd569f52 100644
--- a/gcc/analyzer/analyzer.opt
+++ b/gcc/analyzer/analyzer.opt
@@ -290,6 +290,10 @@ fanalyzer-transitivity
 Common Var(flag_analyzer_transitivity) Init(0)
 Enable transitivity of constraints during analysis.
 
+fanalyzer-show-events-in-system-headers
+Common Var(flag_analyzer_show_events_in_system_headers) Init(0)
+Trim diagnostics path that are too long before emission.
+
 fanalyzer-call-summaries
 Common Var(flag_analyzer_call_summaries) Init(0)
 Approximate the effect of function calls to simplify analysis.
diff --git a/gcc/analyzer/diagnostic-manager.cc b/gcc/analyzer/diagnostic-manager.cc
index cfca305d552..2a9705a464f 100644
--- a/gcc/analyzer/diagnostic-manager.cc
+++ b/gcc/analyzer/diagnostic-manager.cc
@@ -20,9 +20,11 @@ along with GCC; see the file COPYING3.  If not see
 
 #include "config.h"
 #define INCLUDE_MEMORY
+#define INCLUDE_VECTOR
 #include "system.h"
 #include "coretypes.h"
 #include "tree.h"
+#include "input.h"
 #include "pretty-print.h"
 #include "gcc-rich-location.h"
 #include "gimple-pretty-print.h"
@@ -2281,6 +2283,8 @@ diagnostic_manager::prune_path (checker_path *path,
   path->maybe_log (get_logger (), "path");
   prune_for_sm_diagnostic (path, sm, sval, state);
   prune_interproc_events (path);
+  if (! flag_analyzer_show_events_in_system_headers)
+    prune_system_headers (path);
   consolidate_conditions (path);
   finish_pruning (path);
   path->maybe_log (get_logger (), "pruned");
@@ -2667,6 +2671,67 @@ diagnostic_manager::prune_interproc_events (checker_path *path) const
   while (changed);
 }
 
+/* Remove everything within [call point, IDX]. For consistency,
+   IDX should represent the return event of the frame to delete,
+   or if there is none it should be the last event of the frame.
+   After this function, IDX designates the event prior to calling
+   this frame.  */
+
+static void
+prune_frame (checker_path *path, int &idx)
+{
+  gcc_assert (idx >= 0);
+  int nesting = 1;
+  if (path->get_checker_event (idx)->is_return_p ())
+    nesting = 0;
+  do
+    {
+      if (path->get_checker_event (idx)->is_call_p ())
+	nesting--;
+      else if (path->get_checker_event (idx)->is_return_p ())
+	nesting++;
+
+      path->delete_event (idx--);
+    } while (idx >= 0 && nesting != 0);
+}
+
+void
+diagnostic_manager::prune_system_headers (checker_path *path) const
+{
+  int idx = (signed)path->num_events () - 1;
+  while (idx >= 0)
+    {
+      const checker_event *event = path->get_checker_event (idx);
+      /* Prune everything between
+	 [..., system entry, (...), system return, ...].  */
+      if (event->is_return_p ()
+	  && in_system_header_at (event->get_location ()))
+      {
+	int ret_idx = idx;
+	label_text desc
+	    (path->get_checker_event (ret_idx)->get_desc (false));
+	prune_frame (path, idx);
+
+	if (get_logger ())
+	{
+	  log ("filtering event %i-%i:"
+	       " system header event: %s",
+	       idx, ret_idx, desc.get ());
+	}
+	// Delete function entry within system headers.
+	if (idx >= 0)
+	  {
+	    event = path->get_checker_event (idx);
+	    if (event->is_function_entry_p ()
+		&& in_system_header_at (event->get_location ()))
+		  path->delete_event (idx);
+    }
+      }
+
+      idx--;
+    }
+}
+
 /* Return true iff event IDX within PATH is on the same line as REF_EXP_LOC.  */
 
 static bool
diff --git a/gcc/analyzer/diagnostic-manager.h b/gcc/analyzer/diagnostic-manager.h
index 9b3e903fc5d..d3022b888dd 100644
--- a/gcc/analyzer/diagnostic-manager.h
+++ b/gcc/analyzer/diagnostic-manager.h
@@ -180,6 +180,7 @@ private:
 				state_machine::state_t state) const;
   void update_for_unsuitable_sm_exprs (tree *expr) const;
   void prune_interproc_events (checker_path *path) const;
+  void prune_system_headers (checker_path *path) const;
   void consolidate_conditions (checker_path *path) const;
   void finish_pruning (checker_path *path) const;
 
diff --git a/gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-default.C b/gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-default.C
new file mode 100644
index 00000000000..828afbdd9b4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-default.C
@@ -0,0 +1,19 @@
+/* { dg-additional-options "-fdiagnostics-plain-output" } */
+/* { dg-skip-if "no shared_ptr in C++98" { c++98_only }  } */
+
+#include <memory>
+
+struct A {int x; int y;};
+
+int main () {
+  std::shared_ptr<A> a; /* { dg-line declare_a } */
+  a->x = 4; /* { dg-line deref_a } */ 
+  /* { dg-warning "dereference of NULL" "" { target *-*-* } deref_a } */
+
+  return 0;
+}
+
+/* { dg-note "\\(1\\) 'a\\.std::.+::_M_ptr' is NULL" "" { target c++14_down } declare_a } */
+/* { dg-note "dereference of NULL 'a\\.std.+::operator->\\(\\)'" "" { target *-*-* } deref_a } */
+/* { dg-note "calling 'std::.+::operator->' from 'main'" "" { target *-*-* } deref_a } */
+/* { dg-note "returning to 'main' from 'std::.+::operator->'" "" { target *-*-* } deref_a } */
diff --git a/gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-no.C b/gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-no.C
new file mode 100644
index 00000000000..a6e991b0f08
--- /dev/null
+++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-show-events-in-system-headers-no.C
@@ -0,0 +1,19 @@
+/* { dg-additional-options "-fdiagnostics-plain-output -fno-analyzer-show-events-in-system-headers" } */
+/* { dg-skip-if "no shared_ptr in C++98" { c++98_only }  } */
+
+#include <memory>
+
+struct A {int x; int y;};
+
+int main () {
+  std::shared_ptr<A> a; /* { dg-line declare_a } */
+  a->x = 4; /* { dg-line deref_a } */ 
+  /* { dg-warning "dereference of NULL" "" { target *-*-* } deref_a } */
+
+  return 0;
+}
+
+/* { dg-note "\\(1\\) 'a\\.std::.+::_M_ptr' is NULL" "" { target c++14_down } declare_a } */
+/* { dg-note "dereference of NULL 'a\\.std.+::operator->\\(\\)'" "" { target *-*-* } deref_a } */
+/* { dg-note "calling 'std::.+::operator->' from 'main'" "" { target *-*-* } deref_a } */
+/* { dg-note "returning to 'main' from 'std::.+::operator->'" "" { target *-*-* } deref_a } */
-- 
2.34.1


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-08-14 16:14 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-08-11 11:51 [PATCH] analyzer: New option fanalyzer-show-events-in-system-headers [PR110543] priour.be
2023-08-11 15:38 ` David Malcolm
2023-08-14 15:48   ` [PATCH v2] " priour.be
2023-08-14 16:14     ` David Malcolm

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).