[PATCH] C/116735 - ICE in build_counted_by_ref

[Qing Zhao]

From: qing zhao <qing.z...@oracle.com>

When handling the counted_by attribute, if the corresponding field
doesn't exit, in additiion to issue error, we should also remove
the already added non-existing "counted_by" attribute from the
field_decl.

bootstrapped and regression tested on both x86 and aarch64.
Okay for committing?

thanks.

Qing

==============================

        C/PR 116735

gcc/c/ChangeLog:

        * c-decl.cc (verify_counted_by_attribute): Remove the attribute
        when error.

gcc/testsuite/ChangeLog:

        * gcc.dg/flex-array-counted-by-pr116735.c: New test.
---
 gcc/c/c-decl.cc                               | 31 ++++++++++++-------
 .../gcc.dg/flex-array-counted-by-pr116735.c   | 19 ++++++++++++
 2 files changed, 38 insertions(+), 12 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-pr116735.c

diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index aa7f69d1b7b..ce28b0a1022 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -9502,14 +9502,18 @@ verify_counted_by_attribute (tree struct_type, tree 
field_decl)
 
   tree counted_by_field = lookup_field (struct_type, fieldname);
 
-  /* Error when the field is not found in the containing structure.  */
+  /* Error when the field is not found in the containing structure and
+     remove the corresponding counted_by attribute from the field_decl.  */
   if (!counted_by_field)
-    error_at (DECL_SOURCE_LOCATION (field_decl),
-             "argument %qE to the %qE attribute is not a field declaration"
-             " in the same structure as %qD", fieldname,
-             (get_attribute_name (attr_counted_by)),
-             field_decl);
-
+    {
+      error_at (DECL_SOURCE_LOCATION (field_decl),
+               "argument %qE to the %qE attribute is not a field declaration"
+               " in the same structure as %qD", fieldname,
+               (get_attribute_name (attr_counted_by)),
+               field_decl);
+      DECL_ATTRIBUTES (field_decl)
+       = remove_attribute ("counted_by", DECL_ATTRIBUTES (field_decl));
+    }
   else
   /* Error when the field is not with an integer type.  */
     {
@@ -9518,11 +9522,14 @@ verify_counted_by_attribute (tree struct_type, tree 
field_decl)
       tree real_field = TREE_VALUE (counted_by_field);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (real_field)))
-       error_at (DECL_SOURCE_LOCATION (field_decl),
-                 "argument %qE to the %qE attribute is not a field declaration"
-                 " with an integer type", fieldname,
-                 (get_attribute_name (attr_counted_by)));
-
+       {
+         error_at (DECL_SOURCE_LOCATION (field_decl),
+                   "argument %qE to the %qE attribute is not a field 
declaration"
+                   " with an integer type", fieldname,
+                   (get_attribute_name (attr_counted_by)));
+         DECL_ATTRIBUTES (field_decl)
+           = remove_attribute ("counted_by", DECL_ATTRIBUTES (field_decl));
+       }
     }
 
   return;
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-pr116735.c 
b/gcc/testsuite/gcc.dg/flex-array-counted-by-pr116735.c
new file mode 100644
index 00000000000..958636512b7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-pr116735.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O" } */
+struct foo {
+  int len;
+  int element[] __attribute__ ((__counted_by__ (lenx))); /* { dg-error 
"attribute is not a field declaration in the same structure as" } */
+};
+
+int main ()
+{
+  struct foo *p = __builtin_malloc (sizeof (struct foo) + 3 * sizeof (int));
+  p->len = 1;
+  p->element[0] = 17;
+  p->len = 2;
+  p->element[1] = 13;
+  p->len = 1;
+  int x = p->element[1];
+  return x;
+}
+
-- 
2.43.5