[1/2] c++ modules: streaming enum with no enumerators [PR102600]
Commit Message
For an enum declaration, has_definition returns true iff its TYPE_VALUES
field is non-empty. But this will wrongly return false for an enum that's
defined to have no enumerators as in the below testcase.
This patch fixes has_definition for such enums by checking OPAQUE_ENUM_P
instead, which should always give us the right answer here.
Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
PR c++/102600
gcc/cp/ChangeLog:
* module.cc (has_definition): For an enum declaration, check
OPAQUE_ENUM_P instead of TYPE_VALUES.
gcc/testsuite/ChangeLog:
* g++.dg/modules/enum-9_a.H: New test.
* g++.dg/modules/enum-9_b.C: New test.
---
gcc/cp/module.cc | 3 ++-
gcc/testsuite/g++.dg/modules/enum-9_a.H | 5 +++++
gcc/testsuite/g++.dg/modules/enum-9_b.C | 8 ++++++++
3 files changed, 15 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/modules/enum-9_a.H
create mode 100644 gcc/testsuite/g++.dg/modules/enum-9_b.C
Comments
On Tue, 18 Oct 2022, Patrick Palka wrote:
> For an enum declaration, has_definition returns true iff its TYPE_VALUES
> field is non-empty. But this will wrongly return false for an enum that's
> defined to have no enumerators as in the below testcase.
>
> This patch fixes has_definition for such enums by checking OPAQUE_ENUM_P
> instead, which should always give us the right answer here.
Whoops, it looks like the other patch[1] alone fixes both this
testcase and its own testcase, and thus this change to has_definition
isn't necessary if the other patch goes in.
The problem in the below testcase is that the enum defines no enumerators,
so has_definition returns false, and therefore we never stream the
ENUMERAL_TYPE's TYPE_MIN/MAX_VALUE, which leads to a crash in the middle
end due to these fields being empty. The other patch arranges that we
always stream TYPE_MIN/MAX_VALUE for ENUMERAL_TYPE regardless of whether
we think the enum is defined, so this has_definition false negative
doesn't matter anymore. So feel free to ignore this patch if you think
the second one looks good :)
[1]: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/603831.html
>
> Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
>
> PR c++/102600
>
> gcc/cp/ChangeLog:
>
> * module.cc (has_definition): For an enum declaration, check
> OPAQUE_ENUM_P instead of TYPE_VALUES.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/modules/enum-9_a.H: New test.
> * g++.dg/modules/enum-9_b.C: New test.
> ---
> gcc/cp/module.cc | 3 ++-
> gcc/testsuite/g++.dg/modules/enum-9_a.H | 5 +++++
> gcc/testsuite/g++.dg/modules/enum-9_b.C | 8 ++++++++
> 3 files changed, 15 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/modules/enum-9_a.H
> create mode 100644 gcc/testsuite/g++.dg/modules/enum-9_b.C
>
> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> index 2c2f9a9a8cb..cc704817718 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -11443,7 +11443,8 @@ has_definition (tree decl)
> if (type == TYPE_MAIN_VARIANT (type)
> && decl == TYPE_NAME (type)
> && (TREE_CODE (type) == ENUMERAL_TYPE
> - ? TYPE_VALUES (type) : TYPE_FIELDS (type)))
> + ? !OPAQUE_ENUM_P (type)
> + : TYPE_FIELDS (type) != NULL_TREE))
> return true;
> }
> break;
> diff --git a/gcc/testsuite/g++.dg/modules/enum-9_a.H b/gcc/testsuite/g++.dg/modules/enum-9_a.H
> new file mode 100644
> index 00000000000..1aecabfd0bd
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/enum-9_a.H
> @@ -0,0 +1,5 @@
> +// PR c++/102600
> +// { dg-additional-options -fmodule-header }
> +// { dg-module-cmi {} }
> +
> +enum class byte : unsigned char { };
> diff --git a/gcc/testsuite/g++.dg/modules/enum-9_b.C b/gcc/testsuite/g++.dg/modules/enum-9_b.C
> new file mode 100644
> index 00000000000..aa1fdf21444
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/enum-9_b.C
> @@ -0,0 +1,8 @@
> +// PR c++/102600
> +// { dg-additional-options -fmodules-ts }
> +
> +import "enum-9_a.H";
> +
> +void push(byte) {}
> +void write(char v) { push(static_cast<byte>(v)); }
> +int main() { write(char{}); }
> --
> 2.38.0.118.g4732897cf0
>
>
@@ -11443,7 +11443,8 @@ has_definition (tree decl)
if (type == TYPE_MAIN_VARIANT (type)
&& decl == TYPE_NAME (type)
&& (TREE_CODE (type) == ENUMERAL_TYPE
- ? TYPE_VALUES (type) : TYPE_FIELDS (type)))
+ ? !OPAQUE_ENUM_P (type)
+ : TYPE_FIELDS (type) != NULL_TREE))
return true;
}
break;
new file mode 100644
@@ -0,0 +1,5 @@
+// PR c++/102600
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+
+enum class byte : unsigned char { };
new file mode 100644
@@ -0,0 +1,8 @@
+// PR c++/102600
+// { dg-additional-options -fmodules-ts }
+
+import "enum-9_a.H";
+
+void push(byte) {}
+void write(char v) { push(static_cast<byte>(v)); }
+int main() { write(char{}); }