RE: [PATCH] Fix ICE caused by a missing check for DECL_LANG_SPECIFIC

["Matthew Fortune" <mfortune@gmail.com>]

Jason Merrill <jason@redhat.com> writes:
> On Thu, Mar 1, 2018 at 7:02 AM, Matthew Fortune <mfortune@gmail.com>
> wrote:
> > Hi,
> >
> > It seems we have had a bug for some time that causes an ICE and
> prevents the
> > MIPS16 library builds from completing but is likely unrelated to
> MIPS16.
> > The problem is when we call target_reinit and library functions get
> created
> > as shown in the call stack at the end of this message. The first
> builtin
> > that triggers the problem happens to be one of the MIPS16 helpers but
> I
> > don't think there is anything unique about it. The issue appeared
> after some
> > refactoring work in r253600 where code testing DECL_CLASS_SCOPE_P and
> > DECL_FRIEND_P was previously guarded by a check for
> DECL_LANG_SPECIFIC but
> > not after.
> >
> > https://gcc.gnu.org/ml/gcc-patches/2017-10/msg00604.html
> >
> > I don’t know if this is the correct solution or whether we need to
> change the
> > way builtins are initialised in the MIPS backend but I suspect this
> fix
> > is the right way to go.
> >
> > Cc: Jason as author of the original change.
> >
> > Thanks,
> > Matthew
> >
> > gcc/cp/
> >         * pt.c (type_dependent_expression_p): Add missing check for
> >         DECL_LANG_SPECIFIC.
> > ---
> >  gcc/cp/pt.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
> > index 7345119..c88304f 100644
> > --- a/gcc/cp/pt.c
> > +++ b/gcc/cp/pt.c
> > @@ -24635,6 +24635,7 @@ type_dependent_expression_p (tree expression)
> >       type-dependent.  Checking this is important for functions with
> auto return
> >       type, which looks like a dependent type.  */
> >    if (TREE_CODE (expression) == FUNCTION_DECL
> > +      && DECL_LANG_SPECIFIC (expression)
> >        && !(DECL_CLASS_SCOPE_P (expression)
> >            && dependent_type_p (DECL_CONTEXT (expression)))
> >        && !(DECL_FRIEND_P (expression)
> 
> I think we want to go into this block when DECL_LANG_SPECIFIC is NULL.
> Does this also fix the issue for you?

Thanks. Yes, this fixes it too. I wasn't sure which of the accessors were
dependent on DECL_LANG_SPECIFIC so ended up with a sledgehammer. 

Matthew