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-rw-r--r--clang/include/clang/Basic/Attr.td10
-rw-r--r--clang/include/clang/Basic/AttrDocs.td37
-rw-r--r--clang/include/clang/Basic/DiagnosticSemaKinds.td9
-rw-r--r--clang/include/clang/Sema/AttributeList.h1
-rw-r--r--clang/lib/Sema/SemaDecl.cpp74
-rw-r--r--clang/lib/Sema/SemaDeclAttr.cpp3
-rw-r--r--clang/test/SemaCXX/attr-require-constant-initialization.cpp282
-rw-r--r--clang/utils/TableGen/ClangAttrEmitter.cpp4
8 files changed, 393 insertions, 27 deletions
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 7da1efe5ff4..912d1515382 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -241,6 +241,7 @@ def MicrosoftExt : LangOpt<"MicrosoftExt">;
def Borland : LangOpt<"Borland">;
def CUDA : LangOpt<"CUDA">;
def COnly : LangOpt<"CPlusPlus", 1>;
+def CPlusPlus : LangOpt<"CPlusPlus">;
def OpenCL : LangOpt<"OpenCL">;
def RenderScript : LangOpt<"RenderScript">;
@@ -1380,6 +1381,15 @@ def ReqdWorkGroupSize : InheritableAttr {
let Documentation = [Undocumented];
}
+def RequireConstantInit : InheritableAttr {
+ let Spellings = [GNU<"require_constant_initialization">,
+ CXX11<"clang", "require_constant_initialization">];
+ let Subjects = SubjectList<[GlobalVar], ErrorDiag,
+ "ExpectedStaticOrTLSVar">;
+ let Documentation = [RequireConstantInitDocs];
+ let LangOpts = [CPlusPlus];
+}
+
def WorkGroupSizeHint : InheritableAttr {
let Spellings = [GNU<"work_group_size_hint">];
let Args = [UnsignedArgument<"XDim">,
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 9b1ddca05a5..b0375e8779e 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -829,6 +829,43 @@ When one method overrides another, the overriding method can be more widely avai
}];
}
+
+def RequireConstantInitDocs : Documentation {
+ let Category = DocCatVariable;
+ let Content = [{
+This attribute specifies that the variable to which it is attached is intended
+to have a `constant initializer <http://en.cppreference.com/w/cpp/language/constant_initialization>`_
+according to the rules of [basic.start.static]. The variable is required to
+have static or thread storage duration. If the initialization of the variable
+is not a constant initializer, an error will be produced. This attribute may
+only be used in C++.
+
+Note that in C++03 strict constant expression checking is not done. Instead
+the attribute reports if Clang can emit the the variable as a constant, even
+if it's not technically a 'constant initializer'. This behavior is non-portable.
+
+Static storage duration variables with constant initializers avoid hard-to-find
+bugs caused by the indeterminate order of dynamic initialization. They can also
+be safely used during dynamic initialization across translation units.
+
+This attribute acts as a compile time assertion that the requirements
+for constant initialization have been met. Since these requirements change
+between dialects and have subtle pitfalls it's important to fail fast instead
+of silently falling back on dynamic initialization.
+
+.. code-block:: c++
+ // -std=c++14
+ #define SAFE_STATIC __attribute__((require_constant_initialization)) static
+ struct T {
+ constexpr T(int) {}
+ ~T(); // non-trivial
+ };
+ SAFE_STATIC T x = {42}; // Initialization OK. Doesn't check destructor.
+ SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
+ // copy initialization is not a constant expression on a non-literal type.
+ }];
+}
+
def WarnMaybeUnusedDocs : Documentation {
let Category = DocCatVariable;
let Heading = "maybe_unused, unused, gnu::unused";
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index a70b27bac2c..414a6b45e7d 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2572,7 +2572,7 @@ def warn_attribute_wrong_decl_type : Warning<
"Objective-C instance methods|init methods of interface or class extension declarations|"
"variables, functions and classes|"
"functions, variables, classes, and Objective-C interfaces|"
- "Objective-C protocols|"
+ "Objective-C protocols|variables with static or thread storage duration|"
"functions and global variables|structs, unions, and typedefs|structs and typedefs|"
"interface or protocol declarations|kernel functions|non-K&R-style functions|"
"variables, enums, fields and typedefs|functions, methods, enums, and classes|"
@@ -6839,7 +6839,12 @@ def note_inequality_comparison_to_or_assign : Note<
def err_incomplete_type_used_in_type_trait_expr : Error<
"incomplete type %0 used in type trait expression">;
-
+
+def err_require_constant_init_failed : Error<
+ "variable does not have a constant initializer">;
+def note_declared_required_constant_init_here : Note<
+ "required by 'require_constant_initializer' attribute here">;
+
def err_dimension_expr_not_constant_integer : Error<
"dimension expression does not evaluate to a constant unsigned int">;
diff --git a/clang/include/clang/Sema/AttributeList.h b/clang/include/clang/Sema/AttributeList.h
index fcddbecc029..6e3dcd7b622 100644
--- a/clang/include/clang/Sema/AttributeList.h
+++ b/clang/include/clang/Sema/AttributeList.h
@@ -897,6 +897,7 @@ enum AttributeDeclKind {
ExpectedFunctionVariableOrClass,
ExpectedFunctionVariableClassOrObjCInterface,
ExpectedObjectiveCProtocol,
+ ExpectedStaticOrTLSVar,
ExpectedFunctionGlobalVarMethodOrProperty,
ExpectedStructOrUnionOrTypedef,
ExpectedStructOrTypedef,
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 2a514ab1bd2..e6381fbe49f 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -10393,8 +10393,17 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
Diag(var->getLocation(), diag::warn_missing_variable_declarations) << var;
}
+ // Cache the result of checking for constant initialization.
+ Optional<bool> CacheHasConstInit;
+ const Expr *CacheCulprit;
+ auto checkConstInit = [&]() mutable {
+ if (!CacheHasConstInit)
+ CacheHasConstInit = var->getInit()->isConstantInitializer(
+ Context, var->getType()->isReferenceType(), &CacheCulprit);
+ return *CacheHasConstInit;
+ };
+
if (var->getTLSKind() == VarDecl::TLS_Static) {
- const Expr *Culprit;
if (var->getType().isDestructedType()) {
// GNU C++98 edits for __thread, [basic.start.term]p3:
// The type of an object with thread storage duration shall not
@@ -10402,17 +10411,17 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
Diag(var->getLocation(), diag::err_thread_nontrivial_dtor);
if (getLangOpts().CPlusPlus11)
Diag(var->getLocation(), diag::note_use_thread_local);
- } else if (getLangOpts().CPlusPlus && var->hasInit() &&
- !var->getInit()->isConstantInitializer(
- Context, var->getType()->isReferenceType(), &Culprit)) {
- // GNU C++98 edits for __thread, [basic.start.init]p4:
- // An object of thread storage duration shall not require dynamic
- // initialization.
- // FIXME: Need strict checking here.
- Diag(Culprit->getExprLoc(), diag::err_thread_dynamic_init)
- << Culprit->getSourceRange();
- if (getLangOpts().CPlusPlus11)
- Diag(var->getLocation(), diag::note_use_thread_local);
+ } else if (getLangOpts().CPlusPlus && var->hasInit()) {
+ if (!checkConstInit()) {
+ // GNU C++98 edits for __thread, [basic.start.init]p4:
+ // An object of thread storage duration shall not require dynamic
+ // initialization.
+ // FIXME: Need strict checking here.
+ Diag(CacheCulprit->getExprLoc(), diag::err_thread_dynamic_init)
+ << CacheCulprit->getSourceRange();
+ if (getLangOpts().CPlusPlus11)
+ Diag(var->getLocation(), diag::note_use_thread_local);
+ }
}
}
@@ -10486,18 +10495,6 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
if (!var->getDeclContext()->isDependentContext() &&
Init && !Init->isValueDependent()) {
- if (IsGlobal && !var->isConstexpr() &&
- !getDiagnostics().isIgnored(diag::warn_global_constructor,
- var->getLocation())) {
- // Warn about globals which don't have a constant initializer. Don't
- // warn about globals with a non-trivial destructor because we already
- // warned about them.
- CXXRecordDecl *RD = baseType->getAsCXXRecordDecl();
- if (!(RD && !RD->hasTrivialDestructor()) &&
- !Init->isConstantInitializer(Context, baseType->isReferenceType()))
- Diag(var->getLocation(), diag::warn_global_constructor)
- << Init->getSourceRange();
- }
if (var->isConstexpr()) {
SmallVector<PartialDiagnosticAt, 8> Notes;
@@ -10521,6 +10518,35 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
// initialized by a constant expression if we check later.
var->checkInitIsICE();
}
+
+ // Don't emit further diagnostics about constexpr globals since they
+ // were just diagnosed.
+ if (!var->isConstexpr() && GlobalStorage &&
+ var->hasAttr<RequireConstantInitAttr>()) {
+ // FIXME: Need strict checking in C++03 here.
+ bool DiagErr = getLangOpts().CPlusPlus11
+ ? !var->checkInitIsICE() : !checkConstInit();
+ if (DiagErr) {
+ auto attr = var->getAttr<RequireConstantInitAttr>();
+ Diag(var->getLocation(), diag::err_require_constant_init_failed)
+ << Init->getSourceRange();
+ Diag(attr->getLocation(), diag::note_declared_required_constant_init_here)
+ << attr->getRange();
+ }
+ }
+ else if (!var->isConstexpr() && IsGlobal &&
+ !getDiagnostics().isIgnored(diag::warn_global_constructor,
+ var->getLocation())) {
+ // Warn about globals which don't have a constant initializer. Don't
+ // warn about globals with a non-trivial destructor because we already
+ // warned about them.
+ CXXRecordDecl *RD = baseType->getAsCXXRecordDecl();
+ if (!(RD && !RD->hasTrivialDestructor())) {
+ if (!checkConstInit())
+ Diag(var->getLocation(), diag::warn_global_constructor)
+ << Init->getSourceRange();
+ }
+ }
}
// Require the destructor.
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 0471f65cccd..824d68e838e 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5630,6 +5630,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
case AttributeList::AT_VecTypeHint:
handleVecTypeHint(S, D, Attr);
break;
+ case AttributeList::AT_RequireConstantInit:
+ handleSimpleAttribute<RequireConstantInitAttr>(S, D, Attr);
+ break;
case AttributeList::AT_InitPriority:
handleInitPriorityAttr(S, D, Attr);
break;
diff --git a/clang/test/SemaCXX/attr-require-constant-initialization.cpp b/clang/test/SemaCXX/attr-require-constant-initialization.cpp
new file mode 100644
index 00000000000..73f81cb1fc1
--- /dev/null
+++ b/clang/test/SemaCXX/attr-require-constant-initialization.cpp
@@ -0,0 +1,282 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -DTEST_ONE -std=c++03 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -DTEST_ONE -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -DTEST_ONE -std=c++14 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -DTEST_TWO \
+// RUN: -Wglobal-constructors -std=c++14 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -DTEST_THREE -xc %s
+
+#define ATTR __attribute__((require_constant_initialization)) // expected-note 0+ {{expanded from macro}}
+
+int ReturnInt();
+
+struct PODType {
+ int value;
+ int value2;
+};
+
+#if defined(__cplusplus)
+
+#if __cplusplus >= 201103L
+struct LitType {
+ constexpr LitType() : value(0) {}
+ constexpr LitType(int x) : value(x) {}
+ LitType(void *) : value(-1) {}
+ int value;
+};
+#endif
+
+struct NonLit {
+#if __cplusplus >= 201402L
+ constexpr NonLit() : value(0) {}
+ constexpr NonLit(int x) : value(x) {}
+#else
+ NonLit() : value(0) {}
+ NonLit(int x) : value(x) {}
+#endif
+ NonLit(void *) : value(-1) {}
+ ~NonLit() {}
+ int value;
+};
+
+struct StoresNonLit {
+#if __cplusplus >= 201402L
+ constexpr StoresNonLit() : obj() {}
+ constexpr StoresNonLit(int x) : obj(x) {}
+#else
+ StoresNonLit() : obj() {}
+ StoresNonLit(int x) : obj(x) {}
+#endif
+ StoresNonLit(void *p) : obj(p) {}
+ NonLit obj;
+};
+
+#endif // __cplusplus
+
+
+#if defined(TEST_ONE) // Test semantics of attribute
+
+// Test diagnostics when attribute is applied to non-static declarations.
+void test_func_local(ATTR int param) { // expected-error {{only applies to variables with static or thread}}
+ ATTR int x = 42; // expected-error {{only applies to variables with static or thread}}
+ ATTR extern int y;
+}
+struct ATTR class_mem { // expected-error {{only applies to variables with static or thread}}
+ ATTR int x; // expected-error {{only applies to variables with static or thread}}
+};
+
+// [basic.start.static]p2.1
+// if each full-expression (including implicit conversions) that appears in
+// the initializer of a reference with static or thread storage duration is
+// a constant expression (5.20) and the reference is bound to a glvalue
+// designating an object with static storage duration, to a temporary object
+// (see 12.2) or subobject thereof, or to a function;
+
+// Test binding to a static glvalue
+const int glvalue_int = 42;
+const int glvalue_int2 = ReturnInt();
+ATTR const int &glvalue_ref ATTR = glvalue_int;
+ATTR const int &glvalue_ref2 ATTR = glvalue_int2;
+ATTR __thread const int &glvalue_ref_tl = glvalue_int;
+
+void test_basic_start_static_2_1() {
+ const int non_global = 42;
+ ATTR static const int &local_init = non_global; // expected-error {{variable does not have a constant initializer}}
+ // expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ ATTR static const int &global_init = glvalue_int;
+ ATTR static const int &temp_init = 42;
+}
+
+ATTR const int &temp_ref = 42;
+ATTR const int &temp_ref2 = ReturnInt(); // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR const NonLit &nl_temp_ref = 42; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+
+#if __cplusplus >= 201103L
+ATTR const LitType &lit_temp_ref = 42;
+ATTR const int &subobj_ref = LitType{}.value;
+#endif
+
+ATTR const int &nl_subobj_ref = NonLit().value; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+
+struct TT1 {
+ ATTR static const int &no_init;
+ ATTR static const int &glvalue_init;
+ ATTR static const int &temp_init;
+ ATTR static const int &subobj_init;
+#if __cplusplus >= 201103L
+ ATTR static thread_local const int &tl_glvalue_init;
+ ATTR static thread_local const int &tl_temp_init; // expected-note {{required by 'require_constant_initializer' attribute here}}
+#endif
+};
+const int &TT1::glvalue_init = glvalue_int;
+const int &TT1::temp_init = 42;
+const int &TT1::subobj_init = PODType().value;
+#if __cplusplus >= 201103L
+thread_local const int &TT1::tl_glvalue_init = glvalue_int;
+thread_local const int &TT1::tl_temp_init = 42; // expected-error {{variable does not have a constant initializer}}
+#endif
+
+// [basic.start.static]p2.2
+// if an object with static or thread storage duration is initialized by a
+// constructor call, and if the initialization full-expression is a constant
+// initializer for the object;
+
+void test_basic_start_static_2_2() {
+#if __cplusplus < 201103L
+ ATTR static PODType pod;
+#else
+ ATTR static PODType pod; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+#endif
+ ATTR static PODType pot2 = {ReturnInt()}; // expected-error {{variable does not have a constant initializer}}
+ // expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+
+#if __cplusplus >= 201103L
+ constexpr LitType l;
+ ATTR static LitType static_lit = l;
+ ATTR static LitType static_lit2 = (void *)0; // expected-error {{variable does not have a constant initializer}}
+ // expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ ATTR static LitType static_lit3 = ReturnInt(); // expected-error {{variable does not have a constant initializer}}
+ // expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ ATTR thread_local LitType tls = 42;
+#endif
+}
+
+struct TT2 {
+ ATTR static PODType pod_noinit;
+#if __cplusplus >= 201103L
+// expected-note@-2 {{required by 'require_constant_initializer' attribute here}}
+#endif
+ ATTR static PODType pod_copy_init; // expected-note {{required by 'require_constant_initializer' attribute here}}
+#if __cplusplus >= 201402L
+ ATTR static constexpr LitType lit = {};
+ ATTR static const NonLit non_lit;
+ ATTR static const NonLit non_lit_list_init;
+ ATTR static const NonLit non_lit_copy_init; // expected-note {{required by 'require_constant_initializer' attribute here}}
+#endif
+};
+PODType TT2::pod_noinit;
+#if __cplusplus >= 201103L
+// expected-error@-2 {{variable does not have a constant initializer}}
+#endif
+PODType TT2::pod_copy_init(TT2::pod_noinit); // expected-error {{variable does not have a constant initializer}}
+#if __cplusplus >= 201402L
+const NonLit TT2::non_lit(42);
+const NonLit TT2::non_lit_list_init = {42};
+const NonLit TT2::non_lit_copy_init = 42; // expected-error {{variable does not have a constant initializer}}
+#endif
+
+#if __cplusplus >= 201103L
+ATTR LitType lit_ctor;
+ATTR LitType lit_ctor2{};
+ATTR LitType lit_ctor3 = {};
+ATTR __thread LitType lit_ctor_tl = {};
+
+#if __cplusplus >= 201402L
+ATTR NonLit nl_ctor;
+ATTR NonLit nl_ctor2{};
+ATTR NonLit nl_ctor3 = {};
+ATTR thread_local NonLit nl_ctor_tl = {};
+ATTR StoresNonLit snl;
+#else
+ATTR NonLit nl_ctor; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR NonLit nl_ctor2{}; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR NonLit nl_ctor3 = {}; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR thread_local NonLit nl_ctor_tl = {}; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR StoresNonLit snl; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+#endif
+
+// Non-literal types cannot appear in the initializer of a non-literal type.
+ATTR int nl_in_init = NonLit{42}.value; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR int lit_in_init = LitType{42}.value;
+#endif
+
+// [basic.start.static]p2.3
+// if an object with static or thread storage duration is not initialized by a
+// constructor call and if either the object is value-initialized or every
+// full-expression that appears in its initializer is a constant expression.
+void test_basic_start_static_2_3() {
+ ATTR static int static_local = 42;
+ ATTR static int static_local2; // zero-initialization takes place
+#if __cplusplus >= 201103L
+ ATTR thread_local int tl_local = 42;
+#endif
+}
+
+ATTR int no_init; // zero initialization takes place
+ATTR int arg_init = 42;
+ATTR PODType pod_init = {};
+ATTR PODType pod_missing_init = {42 /* should have second arg */};
+ATTR PODType pod_full_init = {1, 2};
+ATTR PODType pod_non_constexpr_init = {1, ReturnInt()}; // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+
+#if __cplusplus >= 201103L
+ATTR int val_init{};
+ATTR int brace_init = {};
+#endif
+
+ATTR __thread int tl_init = 0;
+typedef const char *StrType;
+
+#if __cplusplus >= 201103L
+
+// Test that the validity of the selected constructor is checked, not just the
+// initializer
+struct NotC {
+ constexpr NotC(void *) {}
+ NotC(int) {}
+};
+template <class T>
+struct TestCtor {
+ constexpr TestCtor(int x) : value(x) {}
+ T value;
+};
+ATTR TestCtor<NotC> t(42); // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+#endif
+
+// Test various array types
+ATTR const char *foo[] = {"abc", "def"};
+ATTR PODType bar[] = {{}, {123, 456}};
+
+#elif defined(TEST_TWO) // Test for duplicate warnings
+struct NotC {
+ constexpr NotC(void *) {}
+ NotC(int) {} // expected-note 2 {{declared here}}
+};
+template <class T>
+struct TestCtor {
+ constexpr TestCtor(int x) : value(x) {} // expected-note 2 {{non-constexpr constructor}}
+ T value;
+};
+
+ATTR LitType non_const_lit(nullptr); // expected-error {{variable does not have a constant initializer}}
+// expected-note@-1 {{required by 'require_constant_initializer' attribute here}}
+ATTR NonLit non_const(nullptr); // expected-error {{variable does not have a constant initializer}}
+// expected-warning@-1 {{declaration requires a global destructor}}
+// expected-note@-2 {{required by 'require_constant_initializer' attribute here}}
+LitType const_init_lit(nullptr); // expected-warning {{declaration requires a global constructor}}
+NonLit const_init{42}; // expected-warning {{declaration requires a global destructor}}
+constexpr TestCtor<NotC> inval_constexpr(42); // expected-error {{must be initialized by a constant expression}}
+// expected-note@-1 {{in call to 'TestCtor(42)'}}
+ATTR constexpr TestCtor<NotC> inval_constexpr2(42); // expected-error {{must be initialized by a constant expression}}
+// expected-note@-1 {{in call to 'TestCtor(42)'}}
+
+#elif defined(TEST_THREE)
+#if defined(__cplusplus)
+#error This test requires C
+#endif
+// Test that using the attribute in C results in a diagnostic
+ATTR int x = 0; // expected-warning {{attribute ignored}}
+#else
+#error No test case specified
+#endif // defined(TEST_N)
diff --git a/clang/utils/TableGen/ClangAttrEmitter.cpp b/clang/utils/TableGen/ClangAttrEmitter.cpp
index 50102af33a5..071e06dd93b 100644
--- a/clang/utils/TableGen/ClangAttrEmitter.cpp
+++ b/clang/utils/TableGen/ClangAttrEmitter.cpp
@@ -2790,8 +2790,10 @@ static std::string GenerateLangOptRequirements(const Record &R,
std::string FnName = "check", Test;
for (auto I = LangOpts.begin(), E = LangOpts.end(); I != E; ++I) {
std::string Part = (*I)->getValueAsString("Name");
- if ((*I)->getValueAsBit("Negated"))
+ if ((*I)->getValueAsBit("Negated")) {
+ FnName += "Not";
Test += "!";
+ }
Test += "S.LangOpts." + Part;
if (I + 1 != E)
Test += " || ";
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