On Wed, 2018-12-19 at 20:00 +0100, Thomas Schwinge wrote:
> Hi David!
>
> I will admit that I don't have researched ;-/ what this is actually
> all
> about, and how it's implemented, but...
>
> On Mon, 5 Nov 2018 15:31:08 -0500, David Malcolm <dmalc...@redhat.co
> m> wrote:
> > The C++ frontend gained various location wrapper nodes in r256448
> > (GCC 8).
> > That patch:
> > https://gcc.gnu.org/ml/gcc-patches/2018-01/msg00799.html
> > added wrapper nodes around all nodes with !CAN_HAVE_LOCATION_P for:
> >
> > * arguments at callsites, and for
> >
> > * typeid, alignof, sizeof, and offsetof.
> >
> > This is a followup to that patch, adding many more location
> > wrappers
> > to the C++ frontend. It adds location wrappers for nodes with
> > !CAN_HAVE_LOCATION_P to:
> >
> > * all literal nodes (in cp_parser_primary_expression)
> >
> > * all id-expression nodes (in finish_id_expression), except within
> > a
> > decltype.
> >
> > * all mem-initializer nodes within a mem-initializer-list
> > (in cp_parser_mem_initializer)
> >
> > However, the patch also adds some suppressions: regions in the
> > parser
> > for which wrapper nodes will not be created:
> >
> > * within a template-parameter-list or template-argument-list (in
> > cp_parser_template_parameter_list and
> > cp_parser_template_argument_list
> > respectively), to avoid encoding the spelling location of the
> > nodes
> > in types. For example, "array<10>" and "array<10>" are the same
> > type,
> > despite the fact that the two different "10" tokens are spelled
> > in
> > different locations in the source.
> >
> > * within a gnu-style attribute (none of are handlers are set up to
> > cope
> > with location wrappers yet)
> >
> > * within various OpenMP clauses
I suppressed the addition of wrapper nodes within OpenMP as a way to
reduce the scope of the patch.
> ... I did wonder why things applicable to OpenMP wouldn't likewise
> apply
> to OpenACC, too? That is:
It might or might not be. Maybe there's a gap in my test coverage?
How should I be running the OpenACC tests?
> > (cp_parser_omp_all_clauses): Don't create wrapper nodes within
> > OpenMP clauses.
> > (cp_parser_omp_for_loop): Likewise.
> > (cp_parser_omp_declare_reduction_exprs): Likewise.
> > @@ -33939,6 +33968,9 @@ cp_parser_omp_all_clauses (cp_parser
> > *parser, omp_clause_mask mask,
> > bool first = true;
> > cp_token *token = NULL;
> >
> > + /* Don't create location wrapper nodes within OpenMP
> > clauses. */
> > + auto_suppress_location_wrappers sentinel;
> > +
> > while (cp_lexer_next_token_is_not (parser->lexer,
> > CPP_PRAGMA_EOL))
> > {
> > pragma_omp_clause c_kind;
> > @@ -35223,6 +35255,10 @@ cp_parser_omp_for_loop (cp_parser *parser,
> > enum tree_code code, tree clauses,
> > }
> > loc = cp_lexer_consume_token (parser->lexer)->location;
> >
> > + /* Don't create location wrapper nodes within an OpenMP
> > "for"
> > + statement. */
> > + auto_suppress_location_wrappers sentinel;
> > +
> > matching_parens parens;
> > if (!parens.require_open (parser))
> > return NULL;
> > @@ -37592,6 +37628,8 @@ cp_parser_omp_declare_reduction_exprs (tree
> > fndecl, cp_parser *parser)
> > else
> > {
> > cp_parser_parse_tentatively (parser);
> > + /* Don't create location wrapper nodes here. */
> > + auto_suppress_location_wrappers sentinel;
> > tree fn_name = cp_parser_id_expression (parser,
> > /*template_p=*/false,
> > /*check_dependen
> > cy_p=*/true,
> > /*template_p=*/N
> > ULL,
>
> Shouldn't "cp_parser_oacc_all_clauses" (and "some" other functions?)
> be
> adjusted in the same way? How would I test that? (I don't see any
> OpenMP test cases added -- I have not yet tried whether any problems
> would become apparent when temporarily removing the OpenMP changes
> cited
> above.)
Lots of pre-existing OpenMP test cases started failing when I added the
wrapper nodes to the C++ parser (e.g. for id-expressions and
constants); suppressing them in the given places was an easy way to get
them to pass again.
Dave
