* [PATCH] c++: decltype of capture proxy [PR79378, PR96917]
@ 2023-11-07 19:52 Patrick Palka
2023-11-10 0:40 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2023-11-07 19:52 UTC (permalink / raw)
To: gcc-patches; +Cc: jason, Patrick Palka
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?
-- >8 --
We usually don't see capture proxies in finish_decltype_type because
process_outer_var_ref is a no-op inside an unevaluated context and
so a use of a capture inside decltype refers directly to the captured
variable. But we can still see a capture proxy during decltype(auto)
deduction and for decltype of an init-capture, which suggests we need
to handle capture proxies specially within finish_decltype_type (since
they're always implicitly const). This patch adds such handling.
PR c++/79378
PR c++/96917
gcc/cp/ChangeLog:
* semantics.cc (finish_decltype_type): Handle an id-expression
naming a capture proxy specially.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1y/decltype-auto7.C: New test.
* g++.dg/cpp1y/lambda-init20.C: New test.
---
gcc/cp/semantics.cc | 28 +++++++++--
gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C | 53 +++++++++++++++++++++
gcc/testsuite/g++.dg/cpp1y/lambda-init20.C | 22 +++++++++
3 files changed, 98 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/lambda-init20.C
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 4059e74bdb7..f583dedd6cf 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -11643,12 +11643,30 @@ finish_decltype_type (tree expr, bool id_expression_or_member_access_p,
/* Fall through for fields that aren't bitfields. */
gcc_fallthrough ();
- case FUNCTION_DECL:
case VAR_DECL:
- case CONST_DECL:
- case PARM_DECL:
- case RESULT_DECL:
- case TEMPLATE_PARM_INDEX:
+ if (is_capture_proxy (expr))
+ {
+ if (is_normal_capture_proxy (expr))
+ {
+ expr = DECL_CAPTURED_VARIABLE (expr);
+ type = TREE_TYPE (expr);
+ type = non_reference (type);
+ }
+ else
+ {
+ expr = DECL_VALUE_EXPR (expr);
+ gcc_assert (TREE_CODE (expr) == COMPONENT_REF);
+ expr = TREE_OPERAND (expr, 1);
+ type = TREE_TYPE (expr);
+ }
+ break;
+ }
+ /* Fall through. */
+ case FUNCTION_DECL:
+ case CONST_DECL:
+ case PARM_DECL:
+ case RESULT_DECL:
+ case TEMPLATE_PARM_INDEX:
expr = mark_type_use (expr);
type = TREE_TYPE (expr);
if (VAR_P (expr) && DECL_NTTP_OBJECT_P (expr))
diff --git a/gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C b/gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C
new file mode 100644
index 00000000000..a37b9db38d4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C
@@ -0,0 +1,53 @@
+// PR c++/96917
+// { dg-do compile { target c++14 } }
+
+int main() {
+ int x = 0;
+ int y = 0;
+ const int cx = 0;
+ const int cy = 0;
+
+ [x, &y, cx, &cy] {
+ decltype(auto) a = x;
+ using ty1 = int;
+ using ty1 = decltype(x);
+ using ty1 = decltype(a);
+
+ decltype(auto) b = y;
+ using ty2 = int;
+ using ty2 = decltype(y);
+ using ty2 = decltype(b);
+
+ decltype(auto) ca = cx;
+ using ty3 = const int;
+ using ty3 = decltype(cx);
+ using ty3 = decltype(ca);
+
+ decltype(auto) cb = cy;
+ using ty4 = const int;
+ using ty4 = decltype(cy);
+ using ty4 = decltype(cb);
+ };
+
+ [x=x, &y=y, cx=cx, &cy=cy] {
+ decltype(auto) a = x;
+ using ty1 = int;
+ using ty1 = decltype(x);
+ using ty1 = decltype(a);
+
+ decltype(auto) b = y;
+ using ty2 = int&;
+ using ty2 = decltype(y);
+ using ty2 = decltype(b);
+
+ decltype(auto) ca = cx;
+ using ty3 = int;
+ using ty3 = decltype(cx);
+ using ty3 = decltype(ca);
+
+ decltype(auto) cb = cy;
+ using ty4 = const int&;
+ using ty4 = decltype(cy);
+ using ty4 = decltype(cb);
+ };
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init20.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init20.C
new file mode 100644
index 00000000000..a06b77a664d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init20.C
@@ -0,0 +1,22 @@
+// PR c++/79378
+// { dg-do compile { target c++14 } }
+
+int main() {
+ int x = 0;
+ [x=x, &r=x] {
+ using ty1 = int;
+ using ty1 = decltype(x);
+
+ using ty2 = int&;
+ using ty2 = decltype(r);
+ };
+
+ const int cx = 0;
+ [x=cx, &r=cx] {
+ using ty1 = int;
+ using ty1 = decltype(x);
+
+ using ty2 = const int&;
+ using ty2 = decltype(r);
+ };
+}
--
2.43.0.rc0.23.g8be77c5de6
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] c++: decltype of capture proxy [PR79378, PR96917]
2023-11-07 19:52 [PATCH] c++: decltype of capture proxy [PR79378, PR96917] Patrick Palka
@ 2023-11-10 0:40 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2023-11-10 0:40 UTC (permalink / raw)
To: Patrick Palka, gcc-patches
On 11/7/23 14:52, Patrick Palka wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk?
OK.
> -- >8 --
>
> We usually don't see capture proxies in finish_decltype_type because
> process_outer_var_ref is a no-op inside an unevaluated context and
> so a use of a capture inside decltype refers directly to the captured
> variable. But we can still see a capture proxy during decltype(auto)
> deduction and for decltype of an init-capture, which suggests we need
> to handle capture proxies specially within finish_decltype_type (since
> they're always implicitly const). This patch adds such handling.
>
> PR c++/79378
> PR c++/96917
>
> gcc/cp/ChangeLog:
>
> * semantics.cc (finish_decltype_type): Handle an id-expression
> naming a capture proxy specially.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp1y/decltype-auto7.C: New test.
> * g++.dg/cpp1y/lambda-init20.C: New test.
> ---
> gcc/cp/semantics.cc | 28 +++++++++--
> gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C | 53 +++++++++++++++++++++
> gcc/testsuite/g++.dg/cpp1y/lambda-init20.C | 22 +++++++++
> 3 files changed, 98 insertions(+), 5 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/lambda-init20.C
>
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index 4059e74bdb7..f583dedd6cf 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -11643,12 +11643,30 @@ finish_decltype_type (tree expr, bool id_expression_or_member_access_p,
> /* Fall through for fields that aren't bitfields. */
> gcc_fallthrough ();
>
> - case FUNCTION_DECL:
> case VAR_DECL:
> - case CONST_DECL:
> - case PARM_DECL:
> - case RESULT_DECL:
> - case TEMPLATE_PARM_INDEX:
> + if (is_capture_proxy (expr))
> + {
> + if (is_normal_capture_proxy (expr))
> + {
> + expr = DECL_CAPTURED_VARIABLE (expr);
> + type = TREE_TYPE (expr);
> + type = non_reference (type);
> + }
> + else
> + {
> + expr = DECL_VALUE_EXPR (expr);
> + gcc_assert (TREE_CODE (expr) == COMPONENT_REF);
> + expr = TREE_OPERAND (expr, 1);
> + type = TREE_TYPE (expr);
> + }
> + break;
> + }
> + /* Fall through. */
> + case FUNCTION_DECL:
> + case CONST_DECL:
> + case PARM_DECL:
> + case RESULT_DECL:
> + case TEMPLATE_PARM_INDEX:
> expr = mark_type_use (expr);
> type = TREE_TYPE (expr);
> if (VAR_P (expr) && DECL_NTTP_OBJECT_P (expr))
> diff --git a/gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C b/gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C
> new file mode 100644
> index 00000000000..a37b9db38d4
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/decltype-auto7.C
> @@ -0,0 +1,53 @@
> +// PR c++/96917
> +// { dg-do compile { target c++14 } }
> +
> +int main() {
> + int x = 0;
> + int y = 0;
> + const int cx = 0;
> + const int cy = 0;
> +
> + [x, &y, cx, &cy] {
> + decltype(auto) a = x;
> + using ty1 = int;
> + using ty1 = decltype(x);
> + using ty1 = decltype(a);
> +
> + decltype(auto) b = y;
> + using ty2 = int;
> + using ty2 = decltype(y);
> + using ty2 = decltype(b);
> +
> + decltype(auto) ca = cx;
> + using ty3 = const int;
> + using ty3 = decltype(cx);
> + using ty3 = decltype(ca);
> +
> + decltype(auto) cb = cy;
> + using ty4 = const int;
> + using ty4 = decltype(cy);
> + using ty4 = decltype(cb);
> + };
> +
> + [x=x, &y=y, cx=cx, &cy=cy] {
> + decltype(auto) a = x;
> + using ty1 = int;
> + using ty1 = decltype(x);
> + using ty1 = decltype(a);
> +
> + decltype(auto) b = y;
> + using ty2 = int&;
> + using ty2 = decltype(y);
> + using ty2 = decltype(b);
> +
> + decltype(auto) ca = cx;
> + using ty3 = int;
> + using ty3 = decltype(cx);
> + using ty3 = decltype(ca);
> +
> + decltype(auto) cb = cy;
> + using ty4 = const int&;
> + using ty4 = decltype(cy);
> + using ty4 = decltype(cb);
> + };
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init20.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init20.C
> new file mode 100644
> index 00000000000..a06b77a664d
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init20.C
> @@ -0,0 +1,22 @@
> +// PR c++/79378
> +// { dg-do compile { target c++14 } }
> +
> +int main() {
> + int x = 0;
> + [x=x, &r=x] {
> + using ty1 = int;
> + using ty1 = decltype(x);
> +
> + using ty2 = int&;
> + using ty2 = decltype(r);
> + };
> +
> + const int cx = 0;
> + [x=cx, &r=cx] {
> + using ty1 = int;
> + using ty1 = decltype(x);
> +
> + using ty2 = const int&;
> + using ty2 = decltype(r);
> + };
> +}
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2023-11-10 0:40 ` Jason Merrill
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