[clang] bccdf6b - Improve diagnostic for ignored GNU 'used' attribute

[Fangrui Song via cfe-commits]

Author: Fangrui Song
Date: 2021-02-22T09:18:13-08:00
New Revision: bccdf6b232f67aa4e91f18d49700308f2815ca09

URL: https://github.com/llvm/llvm-project/commit/bccdf6b232f67aa4e91f18d49700308f2815ca09
DIFF: https://github.com/llvm/llvm-project/commit/bccdf6b232f67aa4e91f18d49700308f2815ca09.diff

LOG: Improve diagnostic for ignored GNU 'used' attribute

Differential Revision: https://reviews.llvm.org/D97161

Added: 
    

Modified: 
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/lib/Sema/SemaDecl.cpp
    clang/test/Sema/attr-used.c
    clang/test/SemaCXX/attr-used.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index a7a6b250b5a8..2af3e40d65ce 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3159,6 +3159,9 @@ def warn_attribute_ignored : Warning<"%0 attribute ignored">,
 def warn_nothrow_attribute_ignored : Warning<"'nothrow' attribute conflicts with"
   " exception specification; attribute ignored">,
   InGroup<IgnoredAttributes>;
+def warn_attribute_ignored_on_non_definition :
+  Warning<"%0 attribute ignored on a non-definition declaration">,
+  InGroup<IgnoredAttributes>;
 def warn_attribute_ignored_on_inline :
   Warning<"%0 attribute ignored on inline function">,
   InGroup<IgnoredAttributes>;

diff  --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 0f5b5332364a..10f077e244d6 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -13295,7 +13295,8 @@ void Sema::FinalizeDeclaration(Decl *ThisDecl) {
 
   if (UsedAttr *Attr = VD->getAttr<UsedAttr>()) {
     if (!Attr->isInherited() && !VD->isThisDeclarationADefinition()) {
-      Diag(Attr->getLocation(), diag::warn_attribute_ignored) << Attr;
+      Diag(Attr->getLocation(), diag::warn_attribute_ignored_on_non_definition)
+          << Attr;
       VD->dropAttr<UsedAttr>();
     }
   }

diff  --git a/clang/test/Sema/attr-used.c b/clang/test/Sema/attr-used.c
index c13d57c95e61..f5baf06b0d5b 100644
--- a/clang/test/Sema/attr-used.c
+++ b/clang/test/Sema/attr-used.c
@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -verify -fsyntax-only -Wno-private-extern %s
 
-extern int l0 __attribute__((used)); // expected-warning {{'used' attribute ignored}}
-__private_extern__ int l1 __attribute__((used)); // expected-warning {{'used' attribute ignored}}
+extern int l0 __attribute__((used)); // expected-warning {{'used' attribute ignored on a non-definition declaration}}
+__private_extern__ int l1 __attribute__((used)); // expected-warning {{'used' attribute ignored on a non-definition declaration}}
 
 struct __attribute__((used)) s { // expected-warning {{'used' attribute only applies to variables with non-local storage, functions, and Objective-C methods}}
   int x;

diff  --git a/clang/test/SemaCXX/attr-used.cpp b/clang/test/SemaCXX/attr-used.cpp
index 65df861f8321..41d15eea8f52 100644
--- a/clang/test/SemaCXX/attr-used.cpp
+++ b/clang/test/SemaCXX/attr-used.cpp
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
-extern char test1[] __attribute__((used)); // expected-warning {{'used' attribute ignored}}
-extern const char test2[] __attribute__((used)); // expected-warning {{'used' attribute ignored}}
+extern char test1[] __attribute__((used)); // expected-warning {{'used' attribute ignored on a non-definition declaration}}
+extern const char test2[] __attribute__((used)); // expected-warning {{'used' attribute ignored on a non-definition declaration}}
 extern const char test3[] __attribute__((used)) = "";