PR8455: Handle an attribute between a goto label and a variable declaration per

the GNU documentation: the attribute only appertains to the label if it is
followed by a semicolon. Based on a patch by Aaron Ballman!

llvm-svn: 194869

3 files changed, 44 insertions, 1 deletions

diff --git a/clang/test/Misc/ast-dump-attr.cpp b/clang/test/Misc/ast-dump-attr.cpp
index 3efcd098b37..729be1f2477 100644
--- a/clang/test/Misc/ast-dump-attr.cpp
+++ b/clang/test/Misc/ast-dump-attr.cpp
@@ -95,3 +95,19 @@ void *TestVariadicUnsigned1(int) __attribute__((alloc_size(1)));
 void *TestVariadicUnsigned2(int, int) __attribute__((alloc_size(1,2)));
 // CHECK: FunctionDecl{{.*}}TestVariadicUnsigned2
 // CHECK:   AllocSizeAttr{{.*}} 0 1
+
+void TestLabel() {
+L: __attribute__((unused)) int i;
+// CHECK: LabelStmt{{.*}}'L'
+// CHECK: VarDecl{{.*}}i 'int'
+// CHECK-NEXT: UnusedAttr{{.*}}
+
+M: __attribute(()) int j;
+// CHECK: LabelStmt {{.*}} 'M'
+// CHECK-NEXT: DeclStmt
+// CHECK-NEXT: VarDecl {{.*}} j 'int'
+
+N: __attribute(()) ;
+// CHECK: LabelStmt {{.*}} 'N'
+// CHECK-NEXT: NullStmt
+}
diff --git a/clang/test/Sema/warn-unused-label.c b/clang/test/Sema/warn-unused-label.c
index 48370a5fd64..4b1dbbf2469 100644
--- a/clang/test/Sema/warn-unused-label.c
+++ b/clang/test/Sema/warn-unused-label.c
@@ -9,3 +9,7 @@ void f() {
   goto d;
   return;
 }
+
+void PR8455() {
+  L: __attribute__((unused)) return; // ok, no semicolon required
+}
diff --git a/clang/test/SemaCXX/warn-unused-variables.cpp b/clang/test/SemaCXX/warn-unused-variables.cpp
index 00597f929b2..93d2f6f9563 100644
--- a/clang/test/SemaCXX/warn-unused-variables.cpp
+++ b/clang/test/SemaCXX/warn-unused-variables.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -Wunused-variable -verify %s
+// RUN: %clang_cc1 -fsyntax-only -Wunused-variable -Wunused-label -verify %s
 template<typename T> void f() {
   T t;
   t = 17;
@@ -128,3 +128,26 @@ namespace ctor_with_cleanups {
 }
 
 #include "Inputs/warn-unused-variables.h"
+
+namespace PR8455 {
+  void f() {
+    A: // expected-warning {{unused label 'A'}}
+      __attribute__((unused)) int i; // attribute applies to variable
+    B: // attribute applies to label
+      __attribute__((unused)); int j; // expected-warning {{unused variable 'j'}}
+  }
+
+  void g() {
+    C: // unused label 'C' will not appear here because an error occurs
+      __attribute__((unused))
+      #pragma weak unused_local_static  // expected-error {{expected ';' after __attribute__}}
+      ;
+  }
+
+  void h() {
+    D: // expected-warning {{unused label 'D'}}
+      #pragma weak unused_local_static
+      __attribute__((unused))  // expected-warning {{declaration does not declare anything}}
+      ;
+  }
+}