aaron.ballman created this revision.
aaron.ballman added reviewers: erichkeane, cor3ntin, rsmith.
aaron.ballman requested review of this revision.
Herald added a project: clang.
When forming the function type from a declarator, we look for an overloadable
attribute before issuing a diagnostic in C about a function signature
containing only `...`. When the attribute is present, we allow such a
declaration for compatibility with the overloading rules in C++. However, we
were not looking for the attribute in all of the places it is legal to write it
on a declarator and so we only accepted the signature in some forms and
incorrectly rejected the signature in others.
We now check for the attribute preceding the declarator instead of only being
applied to the declarator directly.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D119664
Files:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaType.cpp
clang/test/Sema/overloadable.c
Index: clang/test/Sema/overloadable.c
===================================================================
--- clang/test/Sema/overloadable.c
+++ clang/test/Sema/overloadable.c
@@ -248,3 +248,14 @@
// if take_fn is passed a void (**)(void *), we'll get a warning.
take_fn(fn);
}
+
+// PR53805
+// We previously failed to consider the attribute being written before the
+// declaration when considering whether to allow a variadic signature with no
+// other parameters, and so we handled these cases differently.
+__attribute__((overloadable)) void can_overload_1(...); // ok, was previously
rejected
+void can_overload_2(...) __attribute__((overloadable)); // ok
+[[clang::overloadable]] void can_overload_3(...); // ok, was previously
rejected
+void can_overload_4 [[clang::overloadable]] (...); // ok
+void cannot_overload(...) [[clang::overloadable]]; // expected-error
{{ISO C requires a named parameter before '...'}} \
+ // expected-error
{{'overloadable' attribute cannot be applied to types}}
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -5237,7 +5237,9 @@
// function is marked with the "overloadable" attribute. Scan
// for this attribute now.
if (!FTI.NumParams && FTI.isVariadic && !LangOpts.CPlusPlus)
- if (!D.getAttributes().hasAttribute(ParsedAttr::AT_Overloadable))
+ if (!D.getAttributes().hasAttribute(ParsedAttr::AT_Overloadable) &&
+ !D.getDeclSpec().getAttributes().hasAttribute(
+ ParsedAttr::AT_Overloadable))
S.Diag(FTI.getEllipsisLoc(), diag::err_ellipsis_first_param);
if (FTI.NumParams && FTI.Params[0].Param == nullptr) {
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -77,6 +77,9 @@
- Added support for parameter pack expansion in `clang::annotate`.
+- The ``overloadable`` attribute can now be written in all of the syntactic
+ locations a declaration attribute may appear. Fixes PR53805.
+
Windows Support
---------------
Index: clang/test/Sema/overloadable.c
===================================================================
--- clang/test/Sema/overloadable.c
+++ clang/test/Sema/overloadable.c
@@ -248,3 +248,14 @@
// if take_fn is passed a void (**)(void *), we'll get a warning.
take_fn(fn);
}
+
+// PR53805
+// We previously failed to consider the attribute being written before the
+// declaration when considering whether to allow a variadic signature with no
+// other parameters, and so we handled these cases differently.
+__attribute__((overloadable)) void can_overload_1(...); // ok, was previously rejected
+void can_overload_2(...) __attribute__((overloadable)); // ok
+[[clang::overloadable]] void can_overload_3(...); // ok, was previously rejected
+void can_overload_4 [[clang::overloadable]] (...); // ok
+void cannot_overload(...) [[clang::overloadable]]; // expected-error {{ISO C requires a named parameter before '...'}} \
+ // expected-error {{'overloadable' attribute cannot be applied to types}}
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -5237,7 +5237,9 @@
// function is marked with the "overloadable" attribute. Scan
// for this attribute now.
if (!FTI.NumParams && FTI.isVariadic && !LangOpts.CPlusPlus)
- if (!D.getAttributes().hasAttribute(ParsedAttr::AT_Overloadable))
+ if (!D.getAttributes().hasAttribute(ParsedAttr::AT_Overloadable) &&
+ !D.getDeclSpec().getAttributes().hasAttribute(
+ ParsedAttr::AT_Overloadable))
S.Diag(FTI.getEllipsisLoc(), diag::err_ellipsis_first_param);
if (FTI.NumParams && FTI.Params[0].Param == nullptr) {
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -77,6 +77,9 @@
- Added support for parameter pack expansion in `clang::annotate`.
+- The ``overloadable`` attribute can now be written in all of the syntactic
+ locations a declaration attribute may appear. Fixes PR53805.
+
Windows Support
---------------
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