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
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 8f537ea..e32d619 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -516,11 +516,40 @@
// identifier ':' statement
SourceLocation ColonLoc = ConsumeToken();
- // Read label attributes, if present. attrs will contain both C++11 and GNU
- // attributes (if present) after this point.
- MaybeParseGNUAttributes(attrs);
+ // Read label attributes, if present.
+ StmtResult SubStmt;
+ if (Tok.is(tok::kw___attribute)) {
+ ParsedAttributesWithRange TempAttrs(AttrFactory);
+ ParseGNUAttributes(TempAttrs);
- StmtResult SubStmt(ParseStatement());
+ // In C++, GNU attributes only apply to the label if they are followed by a
+ // semicolon, to disambiguate label attributes from attributes on a labeled
+ // declaration.
+ //
+ // This doesn't quite match what GCC does; if the attribute list is empty
+ // and followed by a semicolon, GCC will reject (it appears to parse the
+ // attributes as part of a statement in that case). That looks like a bug.
+ if (!getLangOpts().CPlusPlus || Tok.is(tok::semi))
+ attrs.takeAllFrom(TempAttrs);
+ else if (isDeclarationStatement()) {
+ StmtVector Stmts;
+ // FIXME: We should do this whether or not we have a declaration
+ // statement, but that doesn't work correctly (because ProhibitAttributes
+ // can't handle GNU attributes), so only call it in the one case where
+ // GNU attributes are allowed.
+ SubStmt = ParseStatementOrDeclarationAfterAttributes(
+ Stmts, /*OnlyStmts*/ true, 0, TempAttrs);
+ if (!TempAttrs.empty() && !SubStmt.isInvalid())
+ SubStmt = Actions.ProcessStmtAttributes(
+ SubStmt.get(), TempAttrs.getList(), TempAttrs.Range);
+ } else {
+ Diag(Tok, diag::err_expected_semi_after) << "__attribute__";
+ }
+ }
+
+ // If we've not parsed a statement yet, parse one now.
+ if (!SubStmt.isInvalid() && !SubStmt.isUsable())
+ SubStmt = ParseStatement();
// Broken substmt shouldn't prevent the label from being added to the AST.
if (SubStmt.isInvalid())
@@ -557,7 +586,7 @@
// out of stack space in our recursive descent parser. As a special case,
// flatten this recursion into an iterative loop. This is complex and gross,
// but all the grossness is constrained to ParseCaseStatement (and some
- // wierdness in the actions), so this is just local grossness :).
+ // weirdness in the actions), so this is just local grossness :).
// TopLevelCase - This is the highest level we have parsed. 'case 1' in the
// example above.
diff --git a/clang/test/Misc/ast-dump-attr.cpp b/clang/test/Misc/ast-dump-attr.cpp
index 3efcd09..729be1f 100644
--- a/clang/test/Misc/ast-dump-attr.cpp
+++ b/clang/test/Misc/ast-dump-attr.cpp
@@ -95,3 +95,19 @@
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 48370a5..4b1dbbf 100644
--- a/clang/test/Sema/warn-unused-label.c
+++ b/clang/test/Sema/warn-unused-label.c
@@ -9,3 +9,7 @@
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 00597f9..93d2f6f 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 @@
}
#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}}
+ ;
+ }
+}