Fix a thinko that caused us not to compute __builtin_offset as a

constant expression in C. 

llvm-svn: 102762

clang/lib/AST/Expr.cpp

@@ -1943,7 +1943,6 @@ static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) {
     case UnaryOperator::AddrOf:
     case UnaryOperator::Deref:
       return ICEDiag(2, E->getLocStart());
-    case UnaryOperator::OffsetOf:
     case UnaryOperator::Extension:
     case UnaryOperator::LNot:
     case UnaryOperator::Plus:
@@ -1952,7 +1951,11 @@ static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) {
     case UnaryOperator::Real:
     case UnaryOperator::Imag:
       return CheckICE(Exp->getSubExpr(), Ctx);
+    case UnaryOperator::OffsetOf:
+      break;
     }
+    
+    // OffsetOf falls through here.
   }
   case Expr::OffsetOfExprClass: {
       // Note that per C99, offsetof must be an ICE. And AFAIK, using

clang/lib/Sema/TreeTransform.h

@@ -4202,6 +4202,7 @@ TreeTransform<Derived>::TransformOffsetOfExpr(OffsetOfExpr *E) {
   for (unsigned I = 0, N = E->getNumComponents(); I != N; ++I) {
     const Node &ON = E->getComponent(I);
     Component Comp;
+    Comp.isBrackets = true;
     Comp.LocStart = ON.getRange().getBegin();
     Comp.LocEnd = ON.getRange().getEnd();
     switch (ON.getKind()) {

clang/test/Sema/offsetof.c

@@ -62,3 +62,6 @@ struct has_bitfields {
 };
 
 int test3 = __builtin_offsetof(struct has_bitfields, j); // expected-error{{cannot compute offset of bit-field 'j'}}
+
+typedef struct Array { int array[1]; } Array;
+int test4 = __builtin_offsetof(Array, array);