tree-object-size: Don't let error_mark_node escape for ADDR_EXPR [PR105736]

The addr_expr computation does not check for error_mark_node before
returning the size expression.  This used to work in the constant case
because the conversion to uhwi would end up causing it to return
size_unknown, but that won't work for the dynamic case.

Modify the control flow to explicitly return size_unknown if the offset
computation returns an error_mark_node.

gcc/ChangeLog:

	PR tree-optimization/105736
	* tree-object-size.cc (addr_object_size): Return size_unknown
	when object offset computation returns an error.

gcc/testsuite/ChangeLog:

	PR tree-optimization/105736
	* gcc.dg/builtin-dynamic-object-size-0.c (TV4): New struct.
	(val3): New variable.
	(test_pr105736): New test.
	(main): Call it.

Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
(cherry picked from commit 70454c50b4592fe6876ecca13268264e395e058f)

diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
index b5b0b3a..01a280b 100644 (file)
--- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
+++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
@@ -479,6 +479,20 @@ test_loop (int *obj, size_t sz, size_t start, size_t end, int incr)
   return __builtin_dynamic_object_size (ptr, 0);
 }
 
+/* Other tests.  */
+
+struct TV4
+{
+  __attribute__((vector_size (sizeof (int) * 4))) int v;
+};
+
+struct TV4 val3;
+int *
+test_pr105736 (struct TV4 *a)
+{
+  return &a->v[0];
+}
+
 unsigned nfails = 0;
 
 #define FAIL() ({ \
@@ -633,6 +647,10 @@ main (int argc, char **argv)
     FAIL ();
   if (test_loop (arr, 42, 20, 52, 1) != 0)
     FAIL ();
+  /* pr105736.  */
+  int *t = test_pr105736 (&val3);
+  if (__builtin_dynamic_object_size (t, 0) != -1)
+    FAIL ();
 
   if (nfails > 0)
     __builtin_abort ();

diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
index fc062b9..41d21bd 100644 (file)
--- a/gcc/tree-object-size.cc
+++ b/gcc/tree-object-size.cc
@@ -695,19 +695,21 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
        var_size = pt_var_size;
       bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var);
       if (bytes != error_mark_node)
-       bytes = size_for_offset (var_size, bytes);
-      if (var != pt_var
-         && pt_var_size
-         && TREE_CODE (pt_var) == MEM_REF
-         && bytes != error_mark_node)
        {
-         tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var);
-         if (bytes2 != error_mark_node)
+         bytes = size_for_offset (var_size, bytes);
+         if (var != pt_var && pt_var_size && TREE_CODE (pt_var) == MEM_REF)
            {
-             bytes2 = size_for_offset (pt_var_size, bytes2);
-             bytes = size_binop (MIN_EXPR, bytes, bytes2);
+             tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0),
+                                                  pt_var);
+             if (bytes2 != error_mark_node)
+               {
+                 bytes2 = size_for_offset (pt_var_size, bytes2);
+                 bytes = size_binop (MIN_EXPR, bytes, bytes2);
+               }
            }
        }
+      else
+       bytes = size_unknown (object_size_type);
 
       wholebytes
        = object_size_type & OST_SUBOBJECT ? var_size : pt_var_wholesize;