Re: [C++ error-recovery] Fix ICE in walk_subobject_offsets (PR c++/33841)

[Jakub Jelinek <jakub at redhat dot com>]

On Sun, Oct 28, 2007 at 03:54:33PM -0700, Mark Mitchell wrote:
> That might be overly exciting, though, in that there might already be
> references to the FIELD_DECL around (in function bodies), and those
> might get confused if the FIELD_DECL is excised from its class.  So,
> another approach would be just to give it type "int", rather than a type
> of "error_mark_node".  That's a reasonable error-recovery type for a
> bit-field with a non-integral type.  I think that would just be a change
> to the error handling code in check_bitfield_decl.  Patch approved, if
> that works.

I have noticed we already clear the bit-fieldness of the field in case
of error, so rather than changing the type to int or error_mark_node
we can just keep it as is.

Bootstrapped/regtested on x86_64-linux.

2007-10-29  Jakub Jelinek  <jakub@redhat.com>

	PR c++/33841
	* class.c (check_bitfield_decl): Don't set field's type to error_mark_node
	for non-integral type bitfields.  Return true if bitfield is correct, false
	error has been diagnosed.
	(check_field_decls): If check_bitfield_decl returned false, call also
	check_field_decl.

	* g++.dg/other/bitfield3.C: New test.

--- gcc/cp/class.c.jj	2007-10-28 19:34:10.000000000 +0100
+++ gcc/cp/class.c	2007-10-29 12:06:05.000000000 +0100
@@ -139,7 +139,7 @@ static tree build_vtbl_ref_1 (tree, tree
 static tree build_vtbl_initializer (tree, tree, tree, tree, int *);
 static int count_fields (tree);
 static int add_fields_to_record_type (tree, struct sorted_fields_type*, int);
-static void check_bitfield_decl (tree);
+static bool check_bitfield_decl (tree);
 static void check_field_decl (tree, tree, int *, int *, int *);
 static void check_field_decls (tree, tree *, int *, int *);
 static tree *build_base_field (record_layout_info, tree, splay_tree, tree *);
@@ -2655,9 +2655,9 @@ add_fields_to_record_type (tree fields, 
 
 /* FIELD is a bit-field.  We are finishing the processing for its
    enclosing type.  Issue any appropriate messages and set appropriate
-   flags.  */
+   flags.  Returns false if an error has been diagnosed.  */
 
-static void
+static bool
 check_bitfield_decl (tree field)
 {
   tree type = TREE_TYPE (field);
@@ -2675,7 +2675,6 @@ check_bitfield_decl (tree field)
   if (!INTEGRAL_TYPE_P (type))
     {
       error ("bit-field %q+#D with non-integral type", field);
-      TREE_TYPE (field) = error_mark_node;
       w = error_mark_node;
     }
   else
@@ -2720,12 +2719,14 @@ check_bitfield_decl (tree field)
     {
       DECL_SIZE (field) = convert (bitsizetype, w);
       DECL_BIT_FIELD (field) = 1;
+      return true;
     }
   else
     {
       /* Non-bit-fields are aligned for their type.  */
       DECL_BIT_FIELD (field) = 0;
       CLEAR_DECL_C_BIT_FIELD (field);
+      return false;
     }
 }
 
@@ -3037,9 +3038,7 @@ check_field_decls (tree t, tree *access_
 
       /* We set DECL_C_BIT_FIELD in grokbitfield.
 	 If the type and width are valid, we'll also set DECL_BIT_FIELD.  */
-      if (DECL_C_BIT_FIELD (x))
-	check_bitfield_decl (x);
-      else
+      if (! DECL_C_BIT_FIELD (x) || ! check_bitfield_decl (x))
 	check_field_decl (x, t,
 			  cant_have_const_ctor_p,
 			  no_const_asn_ref_p,


	Jakub