Hi,
On 13/04/2018 19:14, Jason Merrill wrote:
On Fri, Apr 13, 2018 at 1:05 PM, Paolo Carlini <paolo.carl...@oracle.com> wrote:
Hi,
On 13/04/2018 16:06, Jason Merrill wrote:
On Fri, Apr 13, 2018 at 5:05 AM, Paolo Carlini <paolo.carl...@oracle.com>
wrote:
Hi,
in this error-recovery regression, after a sensible error message issued
by
cxx_constant_init, store_init_value stores an error_mark_node as
DECL_INITIAL of the VAR_DECL for 'j'. This error_mark_node reappears much
later, to cause a crash during gimplification. As far as I know, the
choice
of storing error_mark_nodes too is the outcome of a rather delicate
error-recovery strategy and I don't think we want to revisit it at this
time, thus the remaining option is catching later the error_mark_node, at
a
"good" time. I note, in passing, that the do loop in gimplify_expr which
uses the crashing STRIP_USELESS_TYPE_CONVERSION seems a bit lacking from
the
error-recovery point of view, because at each iteration it *does* cover
for
error_operand_p (save_expr) but only immediately after the call, when
it's
too late.
All the above said, I believe that at least for the 8.1.0 needs we may
want
to catch the error_mark_node in cp_build_modify_expr, when we are
handling
the assignment 'a.n = j;': convert_for_assignment produces a NOP_EXPR
from
the VAR_DECL for 'j' which then cp_convert_and_check regenerates (deep in
convert_to_integer_1 via maybe_fold_build1_loc) in the final bare-bone
form,
with the error_mark_node as the first operand. Passes testing on
x86_64-linux.
We should avoid wrapping an error_mark_node in a NOP_EXPR in the first
place.
Basing on my analysis, that's easy to do, in convert_to_integer_1.
Are we passing an error_mark_node down into convert_to_integer_1?
Where are we folding away the VAR_DECL?
That convert gets a NOP_EXPR with the VAR_DECL for 'j' as argument and
returns the error_mark_node.
Paolo.
