Properly handle invalid input

See https://savannah.gnu.org/bugs/?44113

* src/parser.c (cleanup_stack): Ignore negative deltas.
(parse_function_declaration): Don't set caller if the symbol
is in automatic storage. Note: that means nested function definitions
can't be handled.
* tests/invalid.at: New test case.
* tests/Makefile.am: Add new test case.
* tests/testsuite.at: Likewise.

5 files changed, 42 insertions, 2 deletions

diff --git a/.gitignore b/.gitignore
index 60d871e..9039854 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,6 +13,7 @@
 ABOUT-NLS
 ChangeLog
 INSTALL
+TAGS
 Makefile
 Makefile.in
 aclocal.m4
diff --git a/src/parser.c b/src/parser.c
index 4126145..4be9d4e 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -274,9 +274,10 @@ cleanup_stack()
 {
      int delta = tos - curs;
 
-     if (delta) 
+     if (delta > 0) 
           memmove(token_stack, token_stack+curs, delta*sizeof(token_stack[0]));
-
+     else if (delta < 0) /* Invalid input */
+          delta = 0;
      tos = delta;
      curs = 0;
 }
@@ -652,6 +653,8 @@ parse_function_declaration(Ident *ident, int parm)
      case LBRACE:
           if (ident->name) {
                caller = lookup(ident->name);
+               if (caller && caller->storage == AutoStorage)
+                    caller = NULL;
                func_body();
           }
           break;
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 5f7d77c..4173c5f 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -48,6 +48,7 @@ TESTSUITE_AT = \
  funcarg.at\
  hiding.at\
  include.at\
+ invalid.at\
  knr.at\
  multi.at\
  nfarg.at\
diff --git a/tests/invalid.at b/tests/invalid.at
new file mode 100644
index 0000000..581f8eb
--- /dev/null
+++ b/tests/invalid.at
@@ -0,0 +1,34 @@
+# This file is part of GNU cflow testsuite. -*- Autotest -*-
+# Copyright (C) 2016 Sergey Poznyakoff
+#
+# This program 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.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([invalid input])
+AT_KEYWORDS([invalid])
+
+# See https://savannah.gnu.org/bugs/?44113
+CFLOW_CHECK([
+m{int
+r(a(n){}e 
+])
+
+CFLOW_CHECK([
+e(S,t)e(S{ 
+])
+
+CFLOW_CHECK([
+n{void y(r(i){}a
+])
+
+AT_CLEANUP
diff --git a/tests/testsuite.at b/tests/testsuite.at
index e516a78..7ed3d7a 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -71,5 +71,6 @@ m4_include([struct02.at])
 m4_include([struct03.at])
 m4_include([struct04.at])
 m4_include([decl01.at])
+m4_include([invalid.at])
 
 # End of testsuite.at