https://github.com/dwblaikie updated
https://github.com/llvm/llvm-project/pull/96699
>From a539afc7b81502ffcab7028bfe8266b8e32951d9 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblai...@gmail.com>
Date: Tue, 25 Jun 2024 21:02:50 +0000
Subject: [PATCH 1/2] Clang: Add warning flag for storage class specifiers on
explicit specializations
With the recent fix for this situation in class members (#93873) (for
which the fixed code is invalid prior to this patch - making migrating
code difficult as it must be in lock-step with the compiler migration,
if building with -Werror) it'd be really useful to be able to disable
this warning during the compiler migration/decouple the compiler
migration from the source fixes.
In theory this approach will regress the codebase to the previous
non-member cases of this issue that were already being held back by the
warning (as opposed to if we carved out the new cases into a separate
warning from the existing cases) but I think this'll be so rare and the
cleanup so simple, that the extra regressions of disabling the warning
broadly won't be too much of a problem. (but if folks disagree, I'm open
to making the warning more fine-grained)
---
clang/include/clang/Basic/DiagnosticGroups.td | 4 ++++
clang/include/clang/Basic/DiagnosticSemaKinds.td | 2 +-
clang/test/Misc/warning-flags.c | 3 +--
3 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td
b/clang/include/clang/Basic/DiagnosticGroups.td
index 9b37d4bd3205b..8c5cbbc160ba1 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -1535,3 +1535,7 @@ def BitIntExtension : DiagGroup<"bit-int-extension">;
// Warnings about misuse of ExtractAPI options.
def ExtractAPIMisuse : DiagGroup<"extractapi-misuse">;
+
+// Warnings about using the non-standard extension having an explicit
specialization
+// with a storage class specifier.
+def ExplicitSpecializationStorageClass :
DiagGroup<"explicit-specialization-storage-class">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 25a87078a5709..f12121f065783 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5366,7 +5366,7 @@ def err_not_class_template_specialization : Error<
"cannot specialize a %select{dependent template|template template "
"parameter}0">;
def ext_explicit_specialization_storage_class : ExtWarn<
- "explicit specialization cannot have a storage class">;
+ "explicit specialization cannot have a storage class">,
InGroup<ExplicitSpecializationStorageClass>;
def err_dependent_function_template_spec_no_match : Error<
"no candidate function template was found for dependent"
" %select{member|friend}0 function template specialization">;
diff --git a/clang/test/Misc/warning-flags.c b/clang/test/Misc/warning-flags.c
index dd73331913c6f..ae14720959a0e 100644
--- a/clang/test/Misc/warning-flags.c
+++ b/clang/test/Misc/warning-flags.c
@@ -18,10 +18,9 @@ This test serves two purposes:
The list of warnings below should NEVER grow. It should gradually shrink to 0.
-CHECK: Warnings without flags (66):
+CHECK: Warnings without flags (65):
CHECK-NEXT: ext_expected_semi_decl_list
-CHECK-NEXT: ext_explicit_specialization_storage_class
CHECK-NEXT: ext_missing_whitespace_after_macro_name
CHECK-NEXT: ext_new_paren_array_nonconst
CHECK-NEXT: ext_plain_complex
>From b3facc9dffc762e3cef93886df23026d502afcae Mon Sep 17 00:00:00 2001
From: David Blaikie <dblai...@gmail.com>
Date: Wed, 26 Jun 2024 00:01:46 +0000
Subject: [PATCH 2/2] Add test
---
clang/test/CXX/dcl.dcl/dcl.spec/dcl.stc/p1.cpp | 16 ++++++++++++----
...n-explicit-specialization-storage-class.cpp | 18 ++++++++++++++++++
2 files changed, 30 insertions(+), 4 deletions(-)
create mode 100644
clang/test/SemaCXX/warn-explicit-specialization-storage-class.cpp
diff --git a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.stc/p1.cpp
b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.stc/p1.cpp
index f6b5d2487e73d..9efa7b67f5bdb 100644
--- a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.stc/p1.cpp
+++ b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.stc/p1.cpp
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,spec %s
+// RUN: %clang_cc1 -fsyntax-only -verify
-Wno-explicit-specialization-storage-class %s
// A storage-class-specifier shall not be specified in an explicit
// specialization (14.7.3) or an explicit instantiation (14.7.2)
@@ -7,13 +8,13 @@ template<typename T> void f(T) {}
template<typename T> static void g(T) {}
-template<> static void f<int>(int); // expected-warning{{explicit
specialization cannot have a storage class}}
+template<> static void f<int>(int); // spec-warning{{explicit specialization
cannot have a storage class}}
template static void f<float>(float); // expected-error{{explicit
instantiation cannot have a storage class}}
template<> void f<double>(double);
template void f<long>(long);
-template<> static void g<int>(int); // expected-warning{{explicit
specialization cannot have a storage class}}
+template<> static void g<int>(int); // spec-warning{{explicit specialization
cannot have a storage class}}
template static void g<float>(float); // expected-error{{explicit
instantiation cannot have a storage class}}
template<> void g<double>(double);
@@ -29,5 +30,12 @@ int X<T>::value = 17;
template static int X<int>::value; // expected-error{{explicit instantiation
cannot have a storage class}}
-template<> static int X<float>::value; // expected-warning{{explicit
specialization cannot have a storage class}}
+template<> static int X<float>::value; // spec-warning{{explicit
specialization cannot have a storage class}}
// expected-error@-1{{'static' can only
be specified inside the class definition}}
+
+struct t1 {
+ template<typename>
+ static void f1();
+ template<>
+ static void f1<int>(); // spec-warning{{explicit specialization cannot have
a storage class}}
+};
diff --git a/clang/test/SemaCXX/warn-explicit-specialization-storage-class.cpp
b/clang/test/SemaCXX/warn-explicit-specialization-storage-class.cpp
new file mode 100644
index 0000000000000..5d9ace292dc06
--- /dev/null
+++ b/clang/test/SemaCXX/warn-explicit-specialization-storage-class.cpp
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only
-Wno-explicit-specialization-storage-class -verify=expnone %s
+
+// expnone-no-diagnostics
+
+struct A {
+ template<typename T>
+ static constexpr int x = 0;
+
+ template<>
+ static constexpr int x<void> = 1; // expected-warning{{explicit
specialization cannot have a storage class}}
+};
+
+template<typename T>
+static constexpr int x = 0;
+
+template<>
+static constexpr int x<void> = 1; // expected-warning{{explicit specialization
cannot have a storage class}}
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