On Sat, Feb 10, 2024 at 08:01:46PM -0800, Andrew Pinski wrote:
> On Sat, Feb 10, 2024 at 7:55 PM Nathaniel Shead
> <nathanielosh...@gmail.com> wrote:
> >
> > Bootstrapped and regtested (so far just modules.exp and dg.exp) on
> > x86_64-pc-linux-gnu, OK for trunk if full regtest succeeds?
> >
> > (Also I noticed I forgot to add the PR to the changelog in my last
> > patch, I've fixed that locally.)
> >
> > -- >8 --
> >
> > After fixing PR111710, I noticed that we currently ICE when declaring a
> > type that derives from 'decltype([]{})'. As far as I can tell this
> > should be legal code, since by [basic.link] p15.2 a lambda defined in a
> > class-specifier should not be TU-local.
> >
> > This patch also adds a bunch of tests for unevaluated lambdas in other
> > contexts, which generally seem to work now.
>
> There are many unevaluated lambdas (non-modules related) bugs report
> (all linked to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107430).
> Do you know if this fixes any of the non-module related ones too?
>
> Thanks,
> Andrew Pinski
>
I took a quick look at the issues linked to the above. I tried a few and
they don't seem to be fixed with these patches; in general I would only
expect changes in modules or potentially with lambdas being used in base
class specifiers, neither of which seem particularly relevant to those
issues.
Nathaniel
> >
> > One interesting case is 'E::f' in the attached testcase: it appears to
> > get a merge kind of 'MK_field', rather than 'MK_keyed' as most other
> > lambdas do. I'm not entirely sure if this will cause issues in the
> > future, but I haven't been able to construct a testcase that causes
> > problems with this, and conversely wrapping the class body in
> > 'start_lambda_scope' causes issues with symbol duplication in COMDAT
> > groups, so I've left it as-is for now.
> >
> > gcc/cp/ChangeLog:
> >
> > * module.cc (trees_out::key_mergeable): Also support TYPE_DECLs.
> > (maybe_key_decl): Likewise.
> > * parser.cc (cp_parser_class_head): Start a lambda scope when
> > parsing base classes.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/modules/lambda-7_a.C:
> > * g++.dg/modules/lambda-7_b.C:
> >
> > Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
> > ---
> > gcc/cp/module.cc | 8 +++++---
> > gcc/cp/parser.cc | 10 ++++++++--
> > gcc/testsuite/g++.dg/modules/lambda-7_a.C | 19 +++++++++++++++++++
> > gcc/testsuite/g++.dg/modules/lambda-7_b.C | 23 +++++++++++++++++++++++
> > 4 files changed, 55 insertions(+), 5 deletions(-)
> >
> > diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> > index 9742bca922c..cceec79b26b 100644
> > --- a/gcc/cp/module.cc
> > +++ b/gcc/cp/module.cc
> > @@ -10784,7 +10784,8 @@ trees_out::key_mergeable (int tag, merge_kind mk,
> > tree decl, tree inner,
> > (TREE_TYPE (inner)));
> > gcc_checking_assert (TREE_CODE (scope) == VAR_DECL
> > || TREE_CODE (scope) == FIELD_DECL
> > - || TREE_CODE (scope) == PARM_DECL);
> > + || TREE_CODE (scope) == PARM_DECL
> > + || TREE_CODE (scope) == TYPE_DECL);
> > auto *root = keyed_table->get (scope);
> > unsigned ix = root->length ();
> > /* If we don't find it, we'll write a really big number
> > @@ -18980,10 +18981,11 @@ maybe_key_decl (tree ctx, tree decl)
> > return;
> >
> > /* We only need to deal with lambdas attached to var, field,
> > - or parm decls. */
> > + parm, or type decls. */
> > if (TREE_CODE (ctx) != VAR_DECL
> > && TREE_CODE (ctx) != FIELD_DECL
> > - && TREE_CODE (ctx) != PARM_DECL)
> > + && TREE_CODE (ctx) != PARM_DECL
> > + && TREE_CODE (ctx) != TYPE_DECL)
> > return;
> >
> > if (!keyed_table)
> > diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> > index 09ecfa23b5d..151e724ed66 100644
> > --- a/gcc/cp/parser.cc
> > +++ b/gcc/cp/parser.cc
> > @@ -27663,10 +27663,16 @@ cp_parser_class_head (cp_parser* parser,
> > if (cp_lexer_next_token_is (parser->lexer, CPP_COLON))
> > {
> > if (type)
> > - pushclass (type);
> > + {
> > + pushclass (type);
> > + start_lambda_scope (TYPE_NAME (type));
> > + }
> > bases = cp_parser_base_clause (parser);
> > if (type)
> > - popclass ();
> > + {
> > + finish_lambda_scope ();
> > + popclass ();
> > + }
> > }
> > else
> > bases = NULL_TREE;
> > diff --git a/gcc/testsuite/g++.dg/modules/lambda-7_a.C
> > b/gcc/testsuite/g++.dg/modules/lambda-7_a.C
> > index 289285cd926..9a23827a280 100644
> > --- a/gcc/testsuite/g++.dg/modules/lambda-7_a.C
> > +++ b/gcc/testsuite/g++.dg/modules/lambda-7_a.C
> > @@ -18,3 +18,22 @@ export struct S {
> > export inline int d(int x, int (*f)(int) = [](int x) { return x * 5; }) {
> > return f(x);
> > }
> > +
> > +// unevaluated lambdas
> > +#if __cplusplus >= 202002L
> > +export struct E : decltype([](int x) { return x * 6; }) {
> > + decltype([](int x) { return x * 7; }) f;
> > +};
> > +
> > +export template <typename T>
> > +struct G : decltype([](int x) { return x * 8; }) {
> > + decltype([](int x) { return x * 9; }) h;
> > +};
> > +
> > +template <>
> > +struct G<double> : decltype([](int x) { return x * 10; }) {
> > + decltype([](int x) { return x * 11; }) i;
> > +};
> > +
> > +export decltype([](int x) { return x * 12; }) j;
> > +#endif
> > diff --git a/gcc/testsuite/g++.dg/modules/lambda-7_b.C
> > b/gcc/testsuite/g++.dg/modules/lambda-7_b.C
> > index a8762399ee1..59a82e05cbf 100644
> > --- a/gcc/testsuite/g++.dg/modules/lambda-7_b.C
> > +++ b/gcc/testsuite/g++.dg/modules/lambda-7_b.C
> > @@ -13,4 +13,27 @@ int main() {
> > __builtin_abort();
> > if (d(10) != 50)
> > __builtin_abort();
> > +
> > +#if __cplusplus >= 202002L
> > + E e;
> > + if (e(10) != 60)
> > + __builtin_abort();
> > + if (e.f(10) != 70)
> > + __builtin_abort();
> > +
> > + G<int> g1;
> > + if (g1(10) != 80)
> > + __builtin_abort();
> > + if (g1.h(10) != 90)
> > + __builtin_abort();
> > +
> > + G<double> g2;
> > + if (g2(10) != 100)
> > + __builtin_abort();
> > + if (g2.i(10) != 110)
> > + __builtin_abort();
> > +
> > + if (j(10) != 120)
> > + __builtin_abort();
> > +#endif
> > }
> > --
> > 2.43.0
> >
