Merge branch 'master' into devel/sphinx

3 files changed, 137 insertions, 17 deletions

diff --git a/gcc/analyzer/ChangeLog b/gcc/analyzer/ChangeLog
index 733580a..6e6b056 100644
--- a/gcc/analyzer/ChangeLog
+++ b/gcc/analyzer/ChangeLog
@@ -1,3 +1,14 @@
+2022-10-26  David Malcolm  <dmalcolm@redhat.com>
+
+	* sm-fd.cc (fd_state_machine::on_open): Transition to "unchecked"
+	when the mode is symbolic, rather than just on integer constants.
+	(fd_state_machine::check_for_open_fd): Don't complain about
+	unchecked values in the start state.
+
+2022-10-26  David Malcolm  <dmalcolm@redhat.com>
+
+	* sm-fd.dot: New file.
+
 2022-10-24  David Malcolm  <dmalcolm@redhat.com>
 
 	PR analyzer/107349
diff --git a/gcc/analyzer/sm-fd.cc b/gcc/analyzer/sm-fd.cc
index 8a4c208..ae846cd 100644
--- a/gcc/analyzer/sm-fd.cc
+++ b/gcc/analyzer/sm-fd.cc
@@ -940,25 +940,25 @@ fd_state_machine::on_open (sm_context *sm_ctxt, const supernode *node,
   if (lhs)
     {
       tree arg = gimple_call_arg (call, 1);
+      enum access_mode mode = READ_WRITE;
       if (TREE_CODE (arg) == INTEGER_CST)
 	{
 	  int flag = TREE_INT_CST_LOW (arg);
-	  enum access_mode mode = get_access_mode_from_flag (flag);
-
-	  switch (mode)
-	    {
-	    case READ_ONLY:
-	      sm_ctxt->on_transition (node, stmt, lhs, m_start,
-				      m_unchecked_read_only);
-	      break;
-	    case WRITE_ONLY:
-	      sm_ctxt->on_transition (node, stmt, lhs, m_start,
-				      m_unchecked_write_only);
-	      break;
-	    default:
-	      sm_ctxt->on_transition (node, stmt, lhs, m_start,
-				      m_unchecked_read_write);
-	    }
+	  mode = get_access_mode_from_flag (flag);
+	}
+      switch (mode)
+	{
+	case READ_ONLY:
+	  sm_ctxt->on_transition (node, stmt, lhs, m_start,
+				  m_unchecked_read_only);
+	  break;
+	case WRITE_ONLY:
+	  sm_ctxt->on_transition (node, stmt, lhs, m_start,
+				  m_unchecked_write_only);
+	  break;
+	default:
+	  sm_ctxt->on_transition (node, stmt, lhs, m_start,
+				  m_unchecked_read_write);
 	}
     }
   else
@@ -1096,7 +1096,7 @@ fd_state_machine::check_for_open_fd (
 
   else
     {
-      if (!(is_valid_fd_p (state) || (state == m_stop)))
+      if (!(is_valid_fd_p (state) || state == m_start || state == m_stop))
 	{
 	  if (!is_constant_fd_p (state))
 	    sm_ctxt->warn (
diff --git a/gcc/analyzer/sm-fd.dot b/gcc/analyzer/sm-fd.dot
new file mode 100644
index 0000000..175daae
--- /dev/null
+++ b/gcc/analyzer/sm-fd.dot
@@ -0,0 +1,109 @@
+/* An overview of the state machine from sm-fd.cc.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by David Malcolm <dmalcolm@redhat.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+/* Keep this in-sync with sm-dot.cc  */
+
+digraph "fd" {
+
+  /* STATES. */
+
+  /* Start state.  */
+  start;
+
+  /* States representing a file descriptor that hasn't yet been
+    checked for validity after opening, for three different
+    access modes.  */
+  unchecked_read_write;
+  unchecked_read_only;
+  unchecked_write_only;
+
+  /* States for representing a file descriptor that is known to be valid (>=
+    0), for three different access modes.  */
+  valid_read_write;
+  valid_read_only;
+  valid_write_only;
+
+  /* State for a file descriptor that is known to be invalid (< 0). */
+  invalid;
+
+  /* State for a file descriptor that has been closed.  */
+  closed;
+
+  /* State for a file descriptor that we do not want to track anymore . */
+  stop;
+
+  /* TRANSITIONS. */
+
+  /* On "open".  */
+  start -> unchecked_read_only [label="on 'X = open(..., O_RDONLY);'"];
+  start -> unchecked_write_only [label="on 'X = open(..., O_WRONLY);'"];
+  start -> unchecked_read_write [label="on 'X = open(..., ...);'"];
+
+  /* On "creat".  */
+  start -> unchecked_write_only [label="on 'X = create(...);'"];
+
+  /* On "close".  */
+  start -> closed [label="on 'close(X);'"];
+  unchecked_read_write -> closed [label="on 'close(X);'"];
+  unchecked_read_only -> closed [label="on 'close(X);'"];
+  unchecked_write_only -> closed [label="on 'close(X);'"];
+  valid_read_write -> closed [label="on 'close(X);'"];
+  valid_read_only -> closed [label="on 'close(X);'"];
+  valid_write_only -> closed [label="on 'close(X);'"];
+  constant_fd -> closed [label="on 'close(X);'"];
+  closed -> stop [label="on 'close(X);':\nWarn('double close')"];
+
+  /* On "read".  */
+  closed -> closed [label="on 'read(X);':\nWarn('use after close')"];
+  unchecked_read_write -> unchecked_read_write [label="on 'read(X);:\nWarn('use without check')'"];
+  unchecked_read_only -> unchecked_read_only [label="on 'read(X);:\nWarn('use without check')'"];
+  unchecked_write_only -> unchecked_write_only [label="on 'read(X);:\nWarn('use without check')'"];
+  valid_write_only -> valid_write_only [label="on 'read(X);:\nWarn('access mode mismatch')'"];
+
+  /* On "write".  */
+  closed -> closed [label="on 'write(X);':\nWarn('use after close')"];
+  unchecked_read_write -> unchecked_read_write [label="on 'write(X);:\nWarn('use without check')'"];
+  unchecked_read_only -> unchecked_read_only [label="on 'write(X);:\nWarn('use without check')'"];
+  unchecked_write_only -> unchecked_write_only [label="on 'write(X);:\nWarn('use without check')'"];
+  valid_read_only -> valid_read_only [label="on 'write(X);:\nWarn('access mode mismatch')'"];
+
+  /* On "dup".  */
+  closed -> closed [label="on 'dup(X);':\nWarn('use after close')"];
+  /* plus stuff for the new fd.  */
+
+  /* On "pipe".  */
+  start -> valid_read_write [label="when 'pipe()' succeeds"];
+
+  /* on_condition.  */
+  unchecked_read_write -> valid_read_write [label="on 'X >= 0'"];
+  unchecked_read_only -> valid_read_only [label="on 'X >= 0'"];
+  unchecked_write_only -> valid_write_only [label="on 'X >= 0'"];
+  unchecked_read_write -> invalid [label="on 'X < 0'"];
+  unchecked_read_only -> invalid [label="on 'X < 0'"];
+  unchecked_write_only -> invalid [label="on 'X < 0'"];
+
+  /* Leaks.  */
+  unchecked_read_write -> stop [label="on leak:\nWarn('leak')"];
+  unchecked_read_only -> stop [label="on leak:\nWarn('leak')"];
+  unchecked_write_only -> stop [label="on leak:\nWarn('leak')"];
+  valid_read_write -> stop [label="on leak:\nWarn('leak')"];
+  valid_read_only -> stop [label="on leak:\nWarn('leak')"];
+  valid_write_only -> stop [label="on leak:\nWarn('leak')"];
+}