The value of a const weak variable is not an integer constant.

llvm-svn: 147575

clang/include/clang/Sema/Initialization.h

@@ -651,6 +651,8 @@ public:
     FK_DefaultInitOfConst,
     /// \brief Initialization of an incomplete type.
     FK_Incomplete,
+    /// \brief Variable-length array must not have an initializer.
+    FK_VariableLengthArrayHasInitializer,
     /// \brief List initialization failed at some point.
     FK_ListInitializationFailed,
     /// \brief Initializer has a placeholder type which cannot be

clang/lib/AST/Decl.cpp

@@ -1422,6 +1422,10 @@ bool VarDecl::evaluateValue(
 }
 
 bool VarDecl::checkInitIsICE() const {
+  // Initializers of weak variables are never ICEs.
+  if (isWeak())
+    return false;
+
   EvaluatedStmt *Eval = ensureEvaluatedStmt();
   if (Eval->CheckedICE)
     // We have already checked whether this subexpression is an

clang/lib/Sema/SemaDecl.cpp

@@ -6045,7 +6045,7 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init,
   // If the type changed, it means we had an incomplete type that was
   // completed by the initializer. For example:
   //   int ary[] = { 1, 3, 5 };
-  // "ary" transitions from a VariableArrayType to a ConstantArrayType.
+  // "ary" transitions from an IncompleteArrayType to a ConstantArrayType.
   if (!VDecl->isInvalidDecl() && (DclT != SavT)) {
     VDecl->setType(DclT);
     Init->setType(DclT.getNonReferenceType());

clang/lib/Sema/SemaInit.cpp

@@ -2427,6 +2427,7 @@ bool InitializationSequence::isAmbiguous() const {
   case FK_ArrayTypeMismatch:
   case FK_NonConstantArrayInit:
   case FK_ListInitializationFailed:
+  case FK_VariableLengthArrayHasInitializer:
   case FK_PlaceholderType:
     return false;
 
@@ -4060,6 +4061,11 @@ InitializationSequence::InitializationSequence(Sema &S,
   //     - Otherwise, if the destination type is an array, the program is
   //       ill-formed.
   if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
+    if (Initializer && isa<VariableArrayType>(DestAT)) {
+      SetFailed(FK_VariableLengthArrayHasInitializer);
+      return;
+    }
+
     if (Initializer && IsStringInit(Initializer, DestAT, Context)) {
       TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
       return;
@@ -5277,6 +5283,11 @@ bool InitializationSequence::Diagnose(Sema &S,
       << Args[0]->getSourceRange();
     break;
 
+  case FK_VariableLengthArrayHasInitializer:
+    S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
+      << Args[0]->getSourceRange();
+    break;
+
   case FK_AddressOfOverloadFailed: {
     DeclAccessPair Found;
     S.ResolveAddressOfOverloadedFunction(Args[0],
@@ -5659,6 +5670,10 @@ void InitializationSequence::dump(raw_ostream &OS) const {
       OS << "list initialization checker failure";
       break;
 
+    case FK_VariableLengthArrayHasInitializer:
+      OS << "variable length array has an initializer";
+      break;
+
     case FK_PlaceholderType:
       OS << "initializer expression isn't contextually valid";
       break;

clang/test/Sema/array-init.c

@@ -167,7 +167,7 @@ void charArrays() {
 
 void variableArrayInit() {
   int a = 4;
-  char strlit[a] = "foo"; //expected-error{{array initializer must be an initializer list or string literal}}
+  char strlit[a] = "foo"; //expected-error{{variable-sized object may not be initialized}}
   int b[a] = { 1, 2, 4 }; //expected-error{{variable-sized object may not be initialized}}
 }
 
@@ -278,3 +278,10 @@ int a6[5] = (int[]){1, 2, 3}; // expected-error{{cannot initialize array of type
 
 int nonconst_value();
 int a7[5] = (int[5]){ 1, 2, 3, 4, nonconst_value() }; // expected-error{{initializer element is not a compile-time constant}}
+
+// <rdar://problem/10636946>
+__attribute__((weak)) const unsigned int test10_bound = 10;
+char test10_global[test10_bound]; // expected-error {{variable length array declaration not allowed at file scope}}
+void test10() {
+  char test10_local[test10_bound] = "help"; // expected-error {{variable-sized object may not be initialized}}
+}