* [pushed] c++: designated init and aggregate members [PR102337]
@ 2022-03-21 20:46 Jason Merrill
2022-03-22 14:19 ` Patrick Palka
0 siblings, 1 reply; 3+ messages in thread
From: Jason Merrill @ 2022-03-21 20:46 UTC (permalink / raw)
To: gcc-patches
Our C++20 designated initializer handling was broken with members of class
type; we would find the relevant member and then try to find a member of
the member with the same name. Or we would sometimes ignore the designator
entirely. The former problem is fixed by the change to reshape_init_class,
the latter by the change to reshape_init_r.
Tested x86_64-pc-linux-gnu, applying to trunk.
PR c++/103337
PR c++/102740
PR c++/103299
PR c++/102538
gcc/cp/ChangeLog:
* decl.cc (reshape_init_class): Avoid looking for designator
after we found it.
(reshape_init_r): Keep looking for designator.
gcc/testsuite/ChangeLog:
* g++.dg/ext/flexary3.C: Remove one error.
* g++.dg/parse/pr43765.C: Likewise.
* g++.dg/cpp2a/desig22.C: New test.
* g++.dg/cpp2a/desig23.C: New test.
* g++.dg/cpp2a/desig24.C: New test.
* g++.dg/cpp2a/desig25.C: New test.
---
gcc/cp/decl.cc | 47 +++++++++++++++++++++++++---
gcc/testsuite/g++.dg/cpp2a/desig22.C | 11 +++++++
gcc/testsuite/g++.dg/cpp2a/desig23.C | 20 ++++++++++++
gcc/testsuite/g++.dg/cpp2a/desig24.C | 11 +++++++
gcc/testsuite/g++.dg/cpp2a/desig25.C | 13 ++++++++
gcc/testsuite/g++.dg/ext/flexary3.C | 2 +-
gcc/testsuite/g++.dg/parse/pr43765.C | 6 ++--
7 files changed, 101 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig22.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig23.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig24.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig25.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 375385e0013..34d9dad9fb0 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -6598,8 +6598,9 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
{
tree field_init;
constructor_elt *old_cur = d->cur;
+ bool direct_desig = false;
- /* Handle designated initializers, as an extension. */
+ /* Handle C++20 designated initializers. */
if (d->cur->index)
{
if (d->cur->index == error_mark_node)
@@ -6617,7 +6618,10 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
}
}
else if (TREE_CODE (d->cur->index) == IDENTIFIER_NODE)
- field = get_class_binding (type, d->cur->index);
+ {
+ field = get_class_binding (type, d->cur->index);
+ direct_desig = true;
+ }
else
{
if (complain & tf_error)
@@ -6669,6 +6673,7 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
break;
gcc_assert (aafield);
field = aafield;
+ direct_desig = false;
}
}
@@ -6683,9 +6688,32 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
assumed to correspond to no elements of the initializer list. */
goto continue_;
- field_init = reshape_init_r (TREE_TYPE (field), d,
- /*first_initializer_p=*/NULL_TREE,
- complain);
+ if (direct_desig)
+ {
+ /* The designated field F is initialized from this one element:
+ Temporarily clear the designator so a recursive reshape_init_class
+ doesn't try to find it again in F, and adjust d->end so we don't
+ try to use the next initializer to initialize another member of F.
+
+ Note that we don't want these changes if we found the designator
+ inside an anon aggr above; we leave them alone to implement:
+
+ "If the element is an anonymous union member and the initializer
+ list is a brace-enclosed designated- initializer-list, the element
+ is initialized by the designated-initializer-list { D }, where D
+ is the designated- initializer-clause naming a member of the
+ anonymous union member." */
+ auto end_ = make_temp_override (d->end, d->cur + 1);
+ auto idx_ = make_temp_override (d->cur->index, NULL_TREE);
+ field_init = reshape_init_r (TREE_TYPE (field), d,
+ /*first_initializer_p=*/NULL_TREE,
+ complain);
+ }
+ else
+ field_init = reshape_init_r (TREE_TYPE (field), d,
+ /*first_initializer_p=*/NULL_TREE,
+ complain);
+
if (field_init == error_mark_node)
return error_mark_node;
@@ -6941,6 +6969,15 @@ reshape_init_r (tree type, reshape_iter *d, tree first_initializer_p,
to handle initialization of arrays and similar. */
else if (COMPOUND_LITERAL_P (stripped_init))
gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
+ /* If we have an unresolved designator, we need to find the member it
+ designates within TYPE, so proceed to the routines below. For
+ FIELD_DECL or INTEGER_CST designators, we're already initializing
+ the designated element. */
+ else if (d->cur->index
+ && TREE_CODE (d->cur->index) == IDENTIFIER_NODE)
+ /* Brace elision with designators is only permitted for anonymous
+ aggregates. */
+ gcc_checking_assert (ANON_AGGR_TYPE_P (type));
/* A CONSTRUCTOR of the target's type is a previously
digested initializer. */
else if (same_type_ignoring_top_level_qualifiers_p (type, init_type))
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig22.C b/gcc/testsuite/g++.dg/cpp2a/desig22.C
new file mode 100644
index 00000000000..ba083f8e3d5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/desig22.C
@@ -0,0 +1,11 @@
+// PR c++/103337
+// { dg-do compile { target c++20 } }
+
+struct op_t {
+ struct put_t {
+ int x;
+ } put;
+};
+
+op_t x{0}; // OK
+op_t y{.put=0}; // bogus error: 'op_t::put_t' has no non-static data member named 'put'
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig23.C b/gcc/testsuite/g++.dg/cpp2a/desig23.C
new file mode 100644
index 00000000000..4354e644f6a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/desig23.C
@@ -0,0 +1,20 @@
+// PR c++/102740
+// { dg-do compile { target c++20 } }
+// { dg-additional-options -Wmissing-braces }
+
+typedef struct {
+ union {
+ struct {
+ const void* content;
+ } put;
+ };
+} op_t;
+
+op_t f(const char* alias) {
+ return op_t{
+ .put =
+ {
+ .content = alias,
+ },
+ }; // { dg-warning "missing braces" }
+}
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig24.C b/gcc/testsuite/g++.dg/cpp2a/desig24.C
new file mode 100644
index 00000000000..219cc9c3b8e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/desig24.C
@@ -0,0 +1,11 @@
+// PR c++/103299
+// { dg-do compile { target c++20 } }
+
+struct foo {
+ union {
+ int fp1{};
+ char fp2;
+ };
+};
+
+static_assert(foo{.fp2={}}.fp2 == 0);
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig25.C b/gcc/testsuite/g++.dg/cpp2a/desig25.C
new file mode 100644
index 00000000000..9da958c29e9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/desig25.C
@@ -0,0 +1,13 @@
+// PR c++/102538
+// { dg-do run { target c++20 } }
+
+struct X { union { char r8[8]; int r32[2]; }; };
+struct Y { X v[1]; };
+Y x = { { { .r32 = { 5, 6 } } } };
+
+int
+main ()
+{
+ if (x.v[0].r32[0] != 5 || x.v[0].r32[1] != 6)
+ __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/ext/flexary3.C b/gcc/testsuite/g++.dg/ext/flexary3.C
index 34b17254f8c..8344b42dd16 100644
--- a/gcc/testsuite/g++.dg/ext/flexary3.C
+++ b/gcc/testsuite/g++.dg/ext/flexary3.C
@@ -16,7 +16,7 @@ struct s {
int main()
{
- struct s s = { .c = 0 }; // { dg-error "initializer" }
+ struct s s = { .c = 0 };
// { dg-error "non-static initialization of a flexible array member" "" { target *-*-* } .-1 }
return 0;
}
diff --git a/gcc/testsuite/g++.dg/parse/pr43765.C b/gcc/testsuite/g++.dg/parse/pr43765.C
index 5e602204007..aa099a4d20b 100644
--- a/gcc/testsuite/g++.dg/parse/pr43765.C
+++ b/gcc/testsuite/g++.dg/parse/pr43765.C
@@ -12,6 +12,6 @@ SomeType vals[] =
{
{ 0, values : temp, }, // { dg-error "either all initializer clauses should be designated or none of them should be" "" { target c++2a } }
0
- }; // { dg-error "GNU-style designated initializer for an array|cannot convert" }
-// (note the error above is on the wrong line)
- // { dg-error "initialization of flexible array member in a nested context" "" { target *-*-* } .-2 }
+ };
+// (note the error below is on the wrong line)
+// { dg-error "initialization of flexible array member in a nested context" "" { target *-*-* } .-2 }
base-commit: 70b8f43695b0e6fabc760d247ac83f354092b21d
prerequisite-patch-id: d89344aafac30ce0b8645945beb2d94b7ddb3515
--
2.27.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [pushed] c++: designated init and aggregate members [PR102337]
2022-03-21 20:46 [pushed] c++: designated init and aggregate members [PR102337] Jason Merrill
@ 2022-03-22 14:19 ` Patrick Palka
2022-03-23 19:35 ` Jason Merrill
0 siblings, 1 reply; 3+ messages in thread
From: Patrick Palka @ 2022-03-22 14:19 UTC (permalink / raw)
To: Jason Merrill; +Cc: gcc-patches
On Mon, 21 Mar 2022, Jason Merrill via Gcc-patches wrote:
> Our C++20 designated initializer handling was broken with members of class
> type; we would find the relevant member and then try to find a member of
> the member with the same name. Or we would sometimes ignore the designator
> entirely. The former problem is fixed by the change to reshape_init_class,
> the latter by the change to reshape_init_r.
>
> Tested x86_64-pc-linux-gnu, applying to trunk.
>
> PR c++/103337
> PR c++/102740
> PR c++/103299
> PR c++/102538
>
> gcc/cp/ChangeLog:
>
> * decl.cc (reshape_init_class): Avoid looking for designator
> after we found it.
> (reshape_init_r): Keep looking for designator.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/ext/flexary3.C: Remove one error.
> * g++.dg/parse/pr43765.C: Likewise.
> * g++.dg/cpp2a/desig22.C: New test.
> * g++.dg/cpp2a/desig23.C: New test.
> * g++.dg/cpp2a/desig24.C: New test.
> * g++.dg/cpp2a/desig25.C: New test.
> ---
> gcc/cp/decl.cc | 47 +++++++++++++++++++++++++---
> gcc/testsuite/g++.dg/cpp2a/desig22.C | 11 +++++++
> gcc/testsuite/g++.dg/cpp2a/desig23.C | 20 ++++++++++++
> gcc/testsuite/g++.dg/cpp2a/desig24.C | 11 +++++++
> gcc/testsuite/g++.dg/cpp2a/desig25.C | 13 ++++++++
> gcc/testsuite/g++.dg/ext/flexary3.C | 2 +-
> gcc/testsuite/g++.dg/parse/pr43765.C | 6 ++--
> 7 files changed, 101 insertions(+), 9 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig22.C
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig23.C
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig24.C
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig25.C
>
> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> index 375385e0013..34d9dad9fb0 100644
> --- a/gcc/cp/decl.cc
> +++ b/gcc/cp/decl.cc
> @@ -6598,8 +6598,9 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
> {
> tree field_init;
> constructor_elt *old_cur = d->cur;
> + bool direct_desig = false;
>
> - /* Handle designated initializers, as an extension. */
> + /* Handle C++20 designated initializers. */
> if (d->cur->index)
> {
> if (d->cur->index == error_mark_node)
> @@ -6617,7 +6618,10 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
> }
> }
> else if (TREE_CODE (d->cur->index) == IDENTIFIER_NODE)
> - field = get_class_binding (type, d->cur->index);
> + {
> + field = get_class_binding (type, d->cur->index);
> + direct_desig = true;
> + }
> else
> {
> if (complain & tf_error)
> @@ -6669,6 +6673,7 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
> break;
> gcc_assert (aafield);
> field = aafield;
> + direct_desig = false;
> }
> }
>
> @@ -6683,9 +6688,32 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
> assumed to correspond to no elements of the initializer list. */
> goto continue_;
>
> - field_init = reshape_init_r (TREE_TYPE (field), d,
> - /*first_initializer_p=*/NULL_TREE,
> - complain);
> + if (direct_desig)
> + {
> + /* The designated field F is initialized from this one element:
> + Temporarily clear the designator so a recursive reshape_init_class
> + doesn't try to find it again in F, and adjust d->end so we don't
> + try to use the next initializer to initialize another member of F.
> +
> + Note that we don't want these changes if we found the designator
> + inside an anon aggr above; we leave them alone to implement:
> +
> + "If the element is an anonymous union member and the initializer
> + list is a brace-enclosed designated- initializer-list, the element
> + is initialized by the designated-initializer-list { D }, where D
> + is the designated- initializer-clause naming a member of the
> + anonymous union member." */
> + auto end_ = make_temp_override (d->end, d->cur + 1);
> + auto idx_ = make_temp_override (d->cur->index, NULL_TREE);
IIUC this override of d->cur->index mutates the underlying CONSTRUCTOR, which
is probably fine, but I wonder if it'd be worthwhile to avoid the mutation by
using a temporary reshape_iter for the recursive call, something like:
constructor_elt elt = { /*index=*/NULL_TREE, d->cur->value };
reshape_iter iter = { &elt, &elt + 1 };
field_init = reshape_init_r (TREE_TYPE (field), &iter,
/*first_initializer_p=*/NULL_TREE,
complain);
d->cur++;
> + field_init = reshape_init_r (TREE_TYPE (field), d,
> + /*first_initializer_p=*/NULL_TREE,
> + complain);
> + }
> + else
> + field_init = reshape_init_r (TREE_TYPE (field), d,
> + /*first_initializer_p=*/NULL_TREE,
> + complain);
> +
> if (field_init == error_mark_node)
> return error_mark_node;
>
> @@ -6941,6 +6969,15 @@ reshape_init_r (tree type, reshape_iter *d, tree first_initializer_p,
> to handle initialization of arrays and similar. */
> else if (COMPOUND_LITERAL_P (stripped_init))
> gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
> + /* If we have an unresolved designator, we need to find the member it
> + designates within TYPE, so proceed to the routines below. For
> + FIELD_DECL or INTEGER_CST designators, we're already initializing
> + the designated element. */
> + else if (d->cur->index
> + && TREE_CODE (d->cur->index) == IDENTIFIER_NODE)
> + /* Brace elision with designators is only permitted for anonymous
> + aggregates. */
> + gcc_checking_assert (ANON_AGGR_TYPE_P (type));
> /* A CONSTRUCTOR of the target's type is a previously
> digested initializer. */
> else if (same_type_ignoring_top_level_qualifiers_p (type, init_type))
> diff --git a/gcc/testsuite/g++.dg/cpp2a/desig22.C b/gcc/testsuite/g++.dg/cpp2a/desig22.C
> new file mode 100644
> index 00000000000..ba083f8e3d5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/desig22.C
> @@ -0,0 +1,11 @@
> +// PR c++/103337
> +// { dg-do compile { target c++20 } }
> +
> +struct op_t {
> + struct put_t {
> + int x;
> + } put;
> +};
> +
> +op_t x{0}; // OK
> +op_t y{.put=0}; // bogus error: 'op_t::put_t' has no non-static data member named 'put'
> diff --git a/gcc/testsuite/g++.dg/cpp2a/desig23.C b/gcc/testsuite/g++.dg/cpp2a/desig23.C
> new file mode 100644
> index 00000000000..4354e644f6a
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/desig23.C
> @@ -0,0 +1,20 @@
> +// PR c++/102740
> +// { dg-do compile { target c++20 } }
> +// { dg-additional-options -Wmissing-braces }
> +
> +typedef struct {
> + union {
> + struct {
> + const void* content;
> + } put;
> + };
> +} op_t;
> +
> +op_t f(const char* alias) {
> + return op_t{
> + .put =
> + {
> + .content = alias,
> + },
> + }; // { dg-warning "missing braces" }
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp2a/desig24.C b/gcc/testsuite/g++.dg/cpp2a/desig24.C
> new file mode 100644
> index 00000000000..219cc9c3b8e
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/desig24.C
> @@ -0,0 +1,11 @@
> +// PR c++/103299
> +// { dg-do compile { target c++20 } }
> +
> +struct foo {
> + union {
> + int fp1{};
> + char fp2;
> + };
> +};
> +
> +static_assert(foo{.fp2={}}.fp2 == 0);
> diff --git a/gcc/testsuite/g++.dg/cpp2a/desig25.C b/gcc/testsuite/g++.dg/cpp2a/desig25.C
> new file mode 100644
> index 00000000000..9da958c29e9
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/desig25.C
> @@ -0,0 +1,13 @@
> +// PR c++/102538
> +// { dg-do run { target c++20 } }
> +
> +struct X { union { char r8[8]; int r32[2]; }; };
> +struct Y { X v[1]; };
> +Y x = { { { .r32 = { 5, 6 } } } };
> +
> +int
> +main ()
> +{
> + if (x.v[0].r32[0] != 5 || x.v[0].r32[1] != 6)
> + __builtin_abort ();
> +}
> diff --git a/gcc/testsuite/g++.dg/ext/flexary3.C b/gcc/testsuite/g++.dg/ext/flexary3.C
> index 34b17254f8c..8344b42dd16 100644
> --- a/gcc/testsuite/g++.dg/ext/flexary3.C
> +++ b/gcc/testsuite/g++.dg/ext/flexary3.C
> @@ -16,7 +16,7 @@ struct s {
>
> int main()
> {
> - struct s s = { .c = 0 }; // { dg-error "initializer" }
> + struct s s = { .c = 0 };
> // { dg-error "non-static initialization of a flexible array member" "" { target *-*-* } .-1 }
> return 0;
> }
> diff --git a/gcc/testsuite/g++.dg/parse/pr43765.C b/gcc/testsuite/g++.dg/parse/pr43765.C
> index 5e602204007..aa099a4d20b 100644
> --- a/gcc/testsuite/g++.dg/parse/pr43765.C
> +++ b/gcc/testsuite/g++.dg/parse/pr43765.C
> @@ -12,6 +12,6 @@ SomeType vals[] =
> {
> { 0, values : temp, }, // { dg-error "either all initializer clauses should be designated or none of them should be" "" { target c++2a } }
> 0
> - }; // { dg-error "GNU-style designated initializer for an array|cannot convert" }
> -// (note the error above is on the wrong line)
> - // { dg-error "initialization of flexible array member in a nested context" "" { target *-*-* } .-2 }
> + };
> +// (note the error below is on the wrong line)
> +// { dg-error "initialization of flexible array member in a nested context" "" { target *-*-* } .-2 }
>
> base-commit: 70b8f43695b0e6fabc760d247ac83f354092b21d
> prerequisite-patch-id: d89344aafac30ce0b8645945beb2d94b7ddb3515
> --
> 2.27.0
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [pushed] c++: designated init and aggregate members [PR102337]
2022-03-22 14:19 ` Patrick Palka
@ 2022-03-23 19:35 ` Jason Merrill
0 siblings, 0 replies; 3+ messages in thread
From: Jason Merrill @ 2022-03-23 19:35 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 4854 bytes --]
On 3/22/22 10:19, Patrick Palka wrote:
> On Mon, 21 Mar 2022, Jason Merrill via Gcc-patches wrote:
>
>> Our C++20 designated initializer handling was broken with members of class
>> type; we would find the relevant member and then try to find a member of
>> the member with the same name. Or we would sometimes ignore the designator
>> entirely. The former problem is fixed by the change to reshape_init_class,
>> the latter by the change to reshape_init_r.
>>
>> Tested x86_64-pc-linux-gnu, applying to trunk.
>>
>> PR c++/103337
>> PR c++/102740
>> PR c++/103299
>> PR c++/102538
>>
>> gcc/cp/ChangeLog:
>>
>> * decl.cc (reshape_init_class): Avoid looking for designator
>> after we found it.
>> (reshape_init_r): Keep looking for designator.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * g++.dg/ext/flexary3.C: Remove one error.
>> * g++.dg/parse/pr43765.C: Likewise.
>> * g++.dg/cpp2a/desig22.C: New test.
>> * g++.dg/cpp2a/desig23.C: New test.
>> * g++.dg/cpp2a/desig24.C: New test.
>> * g++.dg/cpp2a/desig25.C: New test.
>> ---
>> gcc/cp/decl.cc | 47 +++++++++++++++++++++++++---
>> gcc/testsuite/g++.dg/cpp2a/desig22.C | 11 +++++++
>> gcc/testsuite/g++.dg/cpp2a/desig23.C | 20 ++++++++++++
>> gcc/testsuite/g++.dg/cpp2a/desig24.C | 11 +++++++
>> gcc/testsuite/g++.dg/cpp2a/desig25.C | 13 ++++++++
>> gcc/testsuite/g++.dg/ext/flexary3.C | 2 +-
>> gcc/testsuite/g++.dg/parse/pr43765.C | 6 ++--
>> 7 files changed, 101 insertions(+), 9 deletions(-)
>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig22.C
>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig23.C
>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig24.C
>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig25.C
>>
>> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
>> index 375385e0013..34d9dad9fb0 100644
>> --- a/gcc/cp/decl.cc
>> +++ b/gcc/cp/decl.cc
>> @@ -6598,8 +6598,9 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
>> {
>> tree field_init;
>> constructor_elt *old_cur = d->cur;
>> + bool direct_desig = false;
>>
>> - /* Handle designated initializers, as an extension. */
>> + /* Handle C++20 designated initializers. */
>> if (d->cur->index)
>> {
>> if (d->cur->index == error_mark_node)
>> @@ -6617,7 +6618,10 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
>> }
>> }
>> else if (TREE_CODE (d->cur->index) == IDENTIFIER_NODE)
>> - field = get_class_binding (type, d->cur->index);
>> + {
>> + field = get_class_binding (type, d->cur->index);
>> + direct_desig = true;
>> + }
>> else
>> {
>> if (complain & tf_error)
>> @@ -6669,6 +6673,7 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
>> break;
>> gcc_assert (aafield);
>> field = aafield;
>> + direct_desig = false;
>> }
>> }
>>
>> @@ -6683,9 +6688,32 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
>> assumed to correspond to no elements of the initializer list. */
>> goto continue_;
>>
>> - field_init = reshape_init_r (TREE_TYPE (field), d,
>> - /*first_initializer_p=*/NULL_TREE,
>> - complain);
>> + if (direct_desig)
>> + {
>> + /* The designated field F is initialized from this one element:
>> + Temporarily clear the designator so a recursive reshape_init_class
>> + doesn't try to find it again in F, and adjust d->end so we don't
>> + try to use the next initializer to initialize another member of F.
>> +
>> + Note that we don't want these changes if we found the designator
>> + inside an anon aggr above; we leave them alone to implement:
>> +
>> + "If the element is an anonymous union member and the initializer
>> + list is a brace-enclosed designated- initializer-list, the element
>> + is initialized by the designated-initializer-list { D }, where D
>> + is the designated- initializer-clause naming a member of the
>> + anonymous union member." */
>> + auto end_ = make_temp_override (d->end, d->cur + 1);
>> + auto idx_ = make_temp_override (d->cur->index, NULL_TREE);
>
> IIUC this override of d->cur->index mutates the underlying CONSTRUCTOR, which
> is probably fine, but I wonder if it'd be worthwhile to avoid the mutation by
> using a temporary reshape_iter for the recursive call, something like:
>
> constructor_elt elt = { /*index=*/NULL_TREE, d->cur->value };
> reshape_iter iter = { &elt, &elt + 1 };
> field_init = reshape_init_r (TREE_TYPE (field), &iter,
> /*first_initializer_p=*/NULL_TREE,
> complain);
> d->cur++;
Sure, makes sense. I also decided to factor it out.
[-- Attachment #2: 0001-c-tweak-PR103337-fix.patch --]
[-- Type: text/x-patch, Size: 3068 bytes --]
From b64fe36a7e539a26ac0a32aeca2258c23ac3a2df Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Wed, 23 Mar 2022 13:22:25 -0400
Subject: [PATCH] c++: tweak PR103337 fix
To: gcc-patches@gcc.gnu.org
Patrick suggested a way to implement the designated-init handling without
(temporarily) modifying the CONSTRUCTOR being reshaped.
PR c++/103337
gcc/cp/ChangeLog:
* decl.cc (reshape_single_init): New.
(reshape_init_class): Use it.
---
gcc/cp/decl.cc | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 34d9dad9fb0..efef1b7370f 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -6543,6 +6543,21 @@ reshape_init_vector (tree type, reshape_iter *d, tsubst_flags_t complain)
NULL_TREE, complain);
}
+/* Subroutine of reshape_init*: We're initializing an element with TYPE from
+ INIT, in isolation from any designator or other initializers. */
+
+static tree
+reshape_single_init (tree type, tree init, tsubst_flags_t complain)
+{
+ /* We could also implement this by wrapping init in a new CONSTRUCTOR and
+ calling reshape_init, but this way can just live on the stack. */
+ constructor_elt elt = { /*index=*/NULL_TREE, init };
+ reshape_iter iter = { &elt, &elt + 1 };
+ return reshape_init_r (type, &iter,
+ /*first_initializer_p=*/NULL_TREE,
+ complain);
+}
+
/* Subroutine of reshape_init_r, processes the initializers for classes
or union. Parameters are the same of reshape_init_r. */
@@ -6690,24 +6705,19 @@ reshape_init_class (tree type, reshape_iter *d, bool first_initializer_p,
if (direct_desig)
{
- /* The designated field F is initialized from this one element:
- Temporarily clear the designator so a recursive reshape_init_class
- doesn't try to find it again in F, and adjust d->end so we don't
- try to use the next initializer to initialize another member of F.
+ /* The designated field F is initialized from this one element.
- Note that we don't want these changes if we found the designator
- inside an anon aggr above; we leave them alone to implement:
+ Note that we don't want to do this if we found the designator
+ inside an anon aggr above; we use the normal code to implement:
"If the element is an anonymous union member and the initializer
list is a brace-enclosed designated- initializer-list, the element
is initialized by the designated-initializer-list { D }, where D
is the designated- initializer-clause naming a member of the
anonymous union member." */
- auto end_ = make_temp_override (d->end, d->cur + 1);
- auto idx_ = make_temp_override (d->cur->index, NULL_TREE);
- field_init = reshape_init_r (TREE_TYPE (field), d,
- /*first_initializer_p=*/NULL_TREE,
- complain);
+ field_init = reshape_single_init (TREE_TYPE (field),
+ d->cur->value, complain);
+ d->cur++;
}
else
field_init = reshape_init_r (TREE_TYPE (field), d,
--
2.27.0
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-03-21 20:46 [pushed] c++: designated init and aggregate members [PR102337] Jason Merrill
2022-03-22 14:19 ` Patrick Palka
2022-03-23 19:35 ` Jason Merrill
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