[clang] [Clang] diagnose unknown attribute namespaces (PR #138519)
Oleksandr T. via cfe-commits
cfe-commits at lists.llvm.org
Mon May 5 05:36:23 PDT 2025
https://github.com/a-tarasyuk created https://github.com/llvm/llvm-project/pull/138519
This patch enhances Clang's attribute handling by diagnosing unknown attribute namespaces
```c++
[[foo::nodiscard]] int f(); // warning: unknown attribute namespace 'unknown'; attribute 'unknown::foo' ignored
```
>From 7d376b33f09801be504ec65a2853679dff8b726c Mon Sep 17 00:00:00 2001
From: Oleksandr Tarasiuk <oleksandr.tarasiuk at outlook.com>
Date: Mon, 5 May 2025 15:30:14 +0300
Subject: [PATCH] [Clang] diagnose unknown attribute namespaces
---
clang/docs/ReleaseNotes.rst | 2 ++
.../include/clang/Basic/AttributeCommonInfo.h | 4 +++-
.../clang/Basic/DiagnosticCommonKinds.td | 3 +++
clang/lib/Basic/Attributes.cpp | 9 ++++++++-
clang/lib/Sema/SemaDeclAttr.cpp | 19 ++++++++++++-------
clang/test/CXX/module/module.interface/p3.cpp | 2 +-
clang/test/Parser/c2x-attributes.c | 2 +-
clang/test/Parser/cxx0x-attributes.cpp | 6 +++---
clang/test/Sema/unknown-attributes.c | 12 ++++++++++++
9 files changed, 45 insertions(+), 14 deletions(-)
create mode 100644 clang/test/Sema/unknown-attributes.c
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index a80fedebf8f89..d01fc5d1bf46f 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -385,6 +385,8 @@ related warnings within the method body.
- Clang now disallows the use of attributes applied before an
``extern template`` declaration (#GH79893).
+- Clang now diagnoses unknown attribute namespaces
+
Improvements to Clang's diagnostics
-----------------------------------
diff --git a/clang/include/clang/Basic/AttributeCommonInfo.h b/clang/include/clang/Basic/AttributeCommonInfo.h
index 4af5a8fd1852c..ddb022c493bdf 100644
--- a/clang/include/clang/Basic/AttributeCommonInfo.h
+++ b/clang/include/clang/Basic/AttributeCommonInfo.h
@@ -67,7 +67,7 @@ class AttributeCommonInfo {
IgnoredAttribute,
UnknownAttribute,
};
- enum class Scope { NONE, CLANG, GNU, MSVC, OMP, HLSL, GSL, RISCV };
+ enum class Scope { NONE, CLANG, GNU, MSVC, OMP, HLSL, GSL, RISCV, UNKNOWN };
enum class AttrArgsInfo {
None,
Optional,
@@ -234,6 +234,8 @@ class AttributeCommonInfo {
return SyntaxUsed == AS_ContextSensitiveKeyword;
}
+ bool isUnknownScopeName() const;
+
unsigned getAttributeSpellingListIndex() const {
assert((isAttributeSpellingListCalculated() || AttrName) &&
"Spelling cannot be found");
diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
index f26c906b46447..63f4c229b2e76 100644
--- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -177,6 +177,9 @@ def err_opencl_unknown_type_specifier : Error<
"%0 does not support the '%1' "
"%select{type qualifier|storage class specifier}2">;
+def warn_unknown_attribute_namespace : Warning<
+ "unknown attribute namespace '%0'; attribute '%0::%1' ignored">,
+ InGroup<UnknownAttributes>;
def warn_unknown_attribute_ignored : Warning<
"unknown attribute %0 ignored">, InGroup<UnknownAttributes>;
def warn_attribute_ignored : Warning<"%0 attribute ignored">,
diff --git a/clang/lib/Basic/Attributes.cpp b/clang/lib/Basic/Attributes.cpp
index 6a070a99c8d96..c41cbf0fb61f6 100644
--- a/clang/lib/Basic/Attributes.cpp
+++ b/clang/lib/Basic/Attributes.cpp
@@ -191,7 +191,8 @@ getScopeFromNormalizedScopeName(StringRef ScopeName) {
.Case("hlsl", AttributeCommonInfo::Scope::HLSL)
.Case("msvc", AttributeCommonInfo::Scope::MSVC)
.Case("omp", AttributeCommonInfo::Scope::OMP)
- .Case("riscv", AttributeCommonInfo::Scope::RISCV);
+ .Case("riscv", AttributeCommonInfo::Scope::RISCV)
+ .Default(AttributeCommonInfo::Scope::UNKNOWN);
}
unsigned AttributeCommonInfo::calculateAttributeSpellingListIndex() const {
@@ -206,3 +207,9 @@ unsigned AttributeCommonInfo::calculateAttributeSpellingListIndex() const {
#include "clang/Sema/AttrSpellingListIndex.inc"
}
+
+bool AttributeCommonInfo::isUnknownScopeName() const {
+ return getScopeFromNormalizedScopeName(
+ normalizeAttrScopeName(getScopeName(), getSyntax())) ==
+ AttributeCommonInfo::Scope::UNKNOWN;
+}
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index bfb3ee9dcbd16..7dc5a04923946 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -6861,13 +6861,18 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
// though they were unknown attributes.
if (AL.getKind() == ParsedAttr::UnknownAttribute ||
!AL.existsInTarget(S.Context.getTargetInfo())) {
- S.Diag(AL.getLoc(),
- AL.isRegularKeywordAttribute()
- ? (unsigned)diag::err_keyword_not_supported_on_target
- : AL.isDeclspecAttribute()
- ? (unsigned)diag::warn_unhandled_ms_attribute_ignored
- : (unsigned)diag::warn_unknown_attribute_ignored)
- << AL << AL.getRange();
+ if (AL.isUnknownScopeName())
+ S.Diag(AL.getScopeLoc(), diag::warn_unknown_attribute_namespace)
+ << AL.getScopeName()->getName() << AL.getAttrName()->getName()
+ << SourceRange(AL.getScopeLoc(), AL.getRange().getEnd());
+ else
+ S.Diag(AL.getLoc(),
+ AL.isRegularKeywordAttribute()
+ ? (unsigned)diag::err_keyword_not_supported_on_target
+ : AL.isDeclspecAttribute()
+ ? (unsigned)diag::warn_unhandled_ms_attribute_ignored
+ : (unsigned)diag::warn_unknown_attribute_ignored)
+ << AL << AL.getRange();
return;
}
diff --git a/clang/test/CXX/module/module.interface/p3.cpp b/clang/test/CXX/module/module.interface/p3.cpp
index 32819b2dccb11..18758edaf1be7 100644
--- a/clang/test/CXX/module/module.interface/p3.cpp
+++ b/clang/test/CXX/module/module.interface/p3.cpp
@@ -40,7 +40,7 @@ export { // No diagnostic after P2615R1 DR
extern "C++" {} // No diagnostic after P2615R1 DR
}
export [[]]; // No diagnostic after P2615R1 DR
-export [[example::attr]]; // expected-warning {{unknown attribute 'attr'}}
+export [[example::attr]]; // expected-warning {{unknown attribute namespace 'example'; attribute 'example::attr' ignored}}
// [...] shall not declare a name with internal linkage
export static int a; // expected-error {{declaration of 'a' with internal linkage cannot be exported}}
diff --git a/clang/test/Parser/c2x-attributes.c b/clang/test/Parser/c2x-attributes.c
index be039e40f98ef..b5f502c5790d3 100644
--- a/clang/test/Parser/c2x-attributes.c
+++ b/clang/test/Parser/c2x-attributes.c
@@ -133,7 +133,7 @@ void f11(void) {
}
[[attr]] void f12(void); // expected-warning {{unknown attribute 'attr' ignored}}
-[[vendor::attr]] void f13(void); // expected-warning {{unknown attribute 'attr' ignored}}
+[[vendor::attr]] void f13(void); // expected-warning {{unknown attribute namespace 'vendor'; attribute 'vendor::attr' ignored}}
// Ensure that asm statements properly handle double colons.
void test_asm(void) {
diff --git a/clang/test/Parser/cxx0x-attributes.cpp b/clang/test/Parser/cxx0x-attributes.cpp
index fad3010c98b9c..7a0a8b989851f 100644
--- a/clang/test/Parser/cxx0x-attributes.cpp
+++ b/clang/test/Parser/cxx0x-attributes.cpp
@@ -46,7 +46,7 @@ int & [[noreturn]] ref_attr_3 = after_attr; // expected-error {{'noreturn' attri
int && [[]] rref_attr = 0;
int array_attr [1] [[]];
alignas(8) int aligned_attr;
-[[test::valid(for 42 [very] **** '+' symbols went on a trip and had a "good"_time; the end.)]] int garbage_attr; // expected-warning {{unknown attribute 'valid' ignored}}
+[[test::valid(for 42 [very] **** '+' symbols went on a trip and had a "good"_time; the end.)]] int garbage_attr; // expected-warning {{unknown attribute namespace 'test'; attribute 'test::valid' ignored}}
[[,,,static, class, namespace,, inline, constexpr, mutable,, bitand, bitor::compl(!.*_ Cx.!U^*R),,,]] int more_garbage_attr; // expected-warning {{unknown attribute 'static' ignored}} \
// expected-warning {{unknown attribute 'class' ignored}} \
// expected-warning {{unknown attribute 'namespace' ignored}} \
@@ -54,7 +54,7 @@ alignas(8) int aligned_attr;
// expected-warning {{unknown attribute 'constexpr' ignored}} \
// expected-warning {{unknown attribute 'mutable' ignored}} \
// expected-warning {{unknown attribute 'bitand' ignored}} \
- // expected-warning {{unknown attribute 'compl' ignored}}
+ // expected-warning {{unknown attribute namespace 'bitor'; attribute 'bitor::compl' ignored}}
[[u8"invalid!"]] int invalid_string_attr; // expected-error {{expected ']'}}
void fn_attr () [[]];
void noexcept_fn_attr () noexcept [[]];
@@ -269,7 +269,7 @@ template <int... Is> void variadic_nttp() {
void baz [[clang::no_sanitize(Is...)]] (); // expected-error {{expected string literal as argument of 'no_sanitize' attribute}}
void bor [[clang::annotate("A", "V" ...)]] (); // expected-error {{pack expansion does not contain any unexpanded parameter packs}}
void bir [[clang::annotate("B", {1, 2, 3, 4})]] (); // expected-error {{'annotate' attribute requires parameter 1 to be a constant expression}} expected-note {{subexpression not valid in a constant expression}}
- void boo [[unknown::foo(Is...)]] (); // expected-warning {{unknown attribute 'foo' ignored}}
+ void boo [[unknown::foo(Is...)]] (); // expected-warning {{unknown attribute namespace 'unknown'; attribute 'unknown::foo' ignored}}
void faz [[clang::annotate("C", (Is + ...))]] (); // expected-warning {{pack fold expression is a C++17 extension}}
void far [[clang::annotate("D", Is...)]] ();
void foz [[clang::annotate("E", 1, 2, 3, Is...)]] ();
diff --git a/clang/test/Sema/unknown-attributes.c b/clang/test/Sema/unknown-attributes.c
new file mode 100644
index 0000000000000..833ac2f919ea6
--- /dev/null
+++ b/clang/test/Sema/unknown-attributes.c
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -Wunknown-attributes -fsyntax-only -verify %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wunknown-attributes -verify %s
+
+[[foo::a]] // expected-warning {{unknown attribute namespace 'foo'; attribute 'foo::a' ignored}}
+int f1(void) {
+ return 0;
+}
+
+[[clan::deprecated]] // expected-warning {{unknown attribute namespace 'clan'; attribute 'clan::deprecated' ignored}}
+int f2(void) {
+ return 0;
+}
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