re PR sanitizer/70541 (unnoticed invalid dereference when using address sanitizer)

2016-04-08  Maxim Ostapenko  <m.ostapenko@samsung.com>

	PR sanitizer/70541
	* asan.c (instrument_derefs): If we get unknown location, extract it
	with EXPR_LOCATION.
	(maybe_instrument_call): Instrument gimple_call's arguments if needed.

	* c-c++-common/asan/pr70541.c: New test.

From-SVN: r234827

1 files changed, 25 insertions, 3 deletions

diff --git a/gcc/asan.c b/gcc/asan.c
index 47bfdcd..71095fb 100644
--- a/gcc/asan.c
+++ b/gcc/asan.c
@@ -1766,6 +1766,8 @@ instrument_derefs (gimple_stmt_iterator *iter, tree t,
 
   tree type, base;
   HOST_WIDE_INT size_in_bytes;
+  if (location == UNKNOWN_LOCATION)
+    location = EXPR_LOCATION (t);
 
   type = TREE_TYPE (t);
   switch (TREE_CODE (t))
@@ -2049,6 +2051,7 @@ maybe_instrument_call (gimple_stmt_iterator *iter)
       gsi_insert_before (iter, g, GSI_SAME_STMT);
     }
 
+  bool instrumented = false;
   if (gimple_store_p (stmt))
     {
       tree ref_expr = gimple_call_lhs (stmt);
@@ -2056,11 +2059,30 @@ maybe_instrument_call (gimple_stmt_iterator *iter)
 			 gimple_location (stmt),
 			 /*is_store=*/true);
 
-      gsi_next (iter);
-      return true;
+      instrumented = true;
     }
 
-  return false;
+  /* Walk through gimple_call arguments and check them id needed.  */
+  unsigned args_num = gimple_call_num_args (stmt);
+  for (unsigned i = 0; i < args_num; ++i)
+    {
+      tree arg = gimple_call_arg (stmt, i);
+      /* If ARG is not a non-aggregate register variable, compiler in general
+	 creates temporary for it and pass it as argument to gimple call.
+	 But in some cases, e.g. when we pass by value a small structure that
+	 fits to register, compiler can avoid extra overhead by pulling out
+	 these temporaries.  In this case, we should check the argument.  */
+      if (!is_gimple_reg (arg) && !is_gimple_min_invariant (arg))
+	{
+	  instrument_derefs (iter, arg,
+			     gimple_location (stmt),
+			     /*is_store=*/false);
+	  instrumented = true;
+	}
+    }
+  if (instrumented)
+    gsi_next (iter);
+  return instrumented;
 }
 
 /* Walk each instruction of all basic block and instrument those that