On 2/10/24 22:54, Nathaniel Shead 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.
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.
You mean the lambda in the type of E::f? That happens because when we
see a class in the body of another class, we treat it as a member even
if it's a closure. This ought to work fine.
It also works with the suggested direction for
https://github.com/itanium-cxx-abi/cxx-abi/issues/165
So, the patch is OK with the missing ChangeLog bits filled in.
Do we also need to key lambdas to concepts?
template <class T>
concept L = requires { []{ T(); }; };
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
}
