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* [PATCH] Don't instrument DECL_INITIAL of statics (PR sanitizer/66190)
@ 2015-05-21 20:02 Marek Polacek
  2015-05-29  9:14 ` Marek Polacek
  0 siblings, 1 reply; 7+ messages in thread
From: Marek Polacek @ 2015-05-21 20:02 UTC (permalink / raw)
  To: GCC Patches, Jakub Jelinek

In this PR, we find ourselves instrumenting a static initializer and
then crashing when expanding an unlowered UBSAN_NULL.  Jakub suggests
to not instrument DECL_INITIAL of a static variable.  The following
patch is an attempt to do that.  Note that we're still able to sanitize
similar cases (they don't have DECL_INITIAL but something else).

Bootstrap/regtest/bootstrap-ubsan passed on x86_64-linux, ok for trunk?

2015-05-21  Marek Polacek  <polacek@redhat.com>

	PR sanitizer/66190
	* cp-gimplify.c (struct cp_genericize_data): Add no_sanitize_p.
	(cp_genericize_r): Don't instrument static initializers.
	(cp_genericize_tree): Initialize wtd.no_sanitize_p.

	* g++.dg/ubsan/static-init-1.C: New test.
	* g++.dg/ubsan/static-init-2.C: New test.
	* g++.dg/ubsan/static-init-3.C: New test.

diff --git gcc/cp/cp-gimplify.c gcc/cp/cp-gimplify.c
index d5a64fc..778d8f3 100644
--- gcc/cp/cp-gimplify.c
+++ gcc/cp/cp-gimplify.c
@@ -906,6 +906,7 @@ struct cp_genericize_data
   vec<tree> bind_expr_stack;
   struct cp_genericize_omp_taskreg *omp_ctx;
   tree try_block;
+  bool no_sanitize_p;
 };
 
 /* Perform any pre-gimplification lowering of C++ front end trees to
@@ -1150,6 +1151,21 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
       *stmt_p = build1 (NOP_EXPR, void_type_node, integer_zero_node);
       *walk_subtrees = 0;
     }
+  else if ((flag_sanitize
+	    & (SANITIZE_NULL | SANITIZE_ALIGNMENT | SANITIZE_VPTR))
+	   && TREE_CODE (stmt) == DECL_EXPR
+	   && VAR_P (DECL_EXPR_DECL (stmt))
+	   && TREE_STATIC (DECL_EXPR_DECL (stmt))
+	   && DECL_INITIAL (DECL_EXPR_DECL (stmt)))
+    {
+      *walk_subtrees = 0;
+      /* The point here is to not sanitize static initializers.  */
+      bool no_sanitize_p = wtd->no_sanitize_p;
+      wtd->no_sanitize_p = true;
+      cp_walk_tree (&DECL_INITIAL (DECL_EXPR_DECL (stmt)), cp_genericize_r,
+		    data, NULL);
+      wtd->no_sanitize_p = no_sanitize_p;
+    }
   else if (TREE_CODE (stmt) == OMP_PARALLEL || TREE_CODE (stmt) == OMP_TASK)
     {
       struct cp_genericize_omp_taskreg omp_ctx;
@@ -1275,9 +1291,10 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
       if (*stmt_p == error_mark_node)
 	*stmt_p = size_one_node;
       return NULL;
-    }    
-  else if (flag_sanitize
-	   & (SANITIZE_NULL | SANITIZE_ALIGNMENT | SANITIZE_VPTR))
+    }
+  else if ((flag_sanitize
+	    & (SANITIZE_NULL | SANITIZE_ALIGNMENT | SANITIZE_VPTR))
+	   && !wtd->no_sanitize_p)
     {
       if ((flag_sanitize & (SANITIZE_NULL | SANITIZE_ALIGNMENT))
 	  && TREE_CODE (stmt) == NOP_EXPR
@@ -1319,6 +1336,7 @@ cp_genericize_tree (tree* t_p)
   wtd.bind_expr_stack.create (0);
   wtd.omp_ctx = NULL;
   wtd.try_block = NULL_TREE;
+  wtd.no_sanitize_p = false;
   cp_walk_tree (t_p, cp_genericize_r, &wtd, NULL);
   delete wtd.p_set;
   wtd.bind_expr_stack.release ();
diff --git gcc/testsuite/g++.dg/ubsan/static-init-1.C gcc/testsuite/g++.dg/ubsan/static-init-1.C
index e69de29..0b424c0 100644
--- gcc/testsuite/g++.dg/ubsan/static-init-1.C
+++ gcc/testsuite/g++.dg/ubsan/static-init-1.C
@@ -0,0 +1,21 @@
+// PR sanitizer/66190
+// { dg-do compile }
+// { dg-options "-fsanitize=null -std=c++11" }
+
+class A {
+public:
+  void fn1 (int);
+};
+
+class G {
+  ~G ();
+  A t;
+  virtual void fn2 () {
+    static int a;
+    static int &b = a;
+    static int &c (a);
+    static int &d {a};
+    t.fn1 (b);
+  }
+};
+G ::~G () {}
diff --git gcc/testsuite/g++.dg/ubsan/static-init-2.C gcc/testsuite/g++.dg/ubsan/static-init-2.C
index e69de29..d046b33 100644
--- gcc/testsuite/g++.dg/ubsan/static-init-2.C
+++ gcc/testsuite/g++.dg/ubsan/static-init-2.C
@@ -0,0 +1,17 @@
+// PR sanitizer/66190
+// { dg-do run }
+// { dg-options "-fsanitize=null -std=c++11" }
+
+int
+main ()
+{
+  static int *a;
+  static int &b = *a;
+  static int &c (*a);
+  static int &d {*a};
+  return 0;
+}
+
+// { dg-output "reference binding to null pointer of type 'int'(\n|\r\n|\r)" }
+// { dg-output "\[^\n\r]*reference binding to null pointer of type 'int'(\n|\r\n|\r)" }
+// { dg-output "\[^\n\r]*reference binding to null pointer of type 'int'" }
diff --git gcc/testsuite/g++.dg/ubsan/static-init-3.C gcc/testsuite/g++.dg/ubsan/static-init-3.C
index e69de29..7fd6cbd 100644
--- gcc/testsuite/g++.dg/ubsan/static-init-3.C
+++ gcc/testsuite/g++.dg/ubsan/static-init-3.C
@@ -0,0 +1,19 @@
+// PR sanitizer/66190
+// { dg-do run }
+// { dg-options "-fsanitize=null -std=c++11" }
+
+int *fn (void) { return 0; }
+
+int
+main ()
+{
+  static int a;
+  static int &b = *fn ();
+  static int &c (*fn ());
+  static int &d {*fn ()};
+  return 0;
+}
+
+// { dg-output "reference binding to null pointer of type 'int'(\n|\r\n|\r)" }
+// { dg-output "\[^\n\r]*reference binding to null pointer of type 'int'(\n|\r\n|\r)" }
+// { dg-output "\[^\n\r]*reference binding to null pointer of type 'int'" }

	Marek

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2015-06-03 17:01 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-05-21 20:02 [PATCH] Don't instrument DECL_INITIAL of statics (PR sanitizer/66190) Marek Polacek
2015-05-29  9:14 ` Marek Polacek
2015-05-29 10:57   ` Jakub Jelinek
2015-06-03 16:33     ` Marek Polacek
2015-06-03 17:00       ` Jakub Jelinek
2015-06-03 17:01         ` Marek Polacek
2015-06-03 17:09           ` Jakub Jelinek

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