[clang][Interp] Don't retry weak declarations

Author: tbaederr

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -3795,7 +3795,8 @@ bool ByteCodeExprGen<Emitter>::VisitDeclRefExpr(const DeclRefExpr *E) {
     }
   } else {
     if (const auto *VD = dyn_cast<VarDecl>(D);
-        VD && VD->getAnyInitializer() && VD->getType().isConstQualified()) {
+        VD && VD->getAnyInitializer() && VD->getType().isConstQualified() &&
+        !VD->isWeak()) {
       if (!this->visitVarDecl(VD))
         return false;
       // Retry.

clang/test/AST/Interp/c.c

@@ -284,3 +284,9 @@ void *foo5 (void)
 {
   return &cv2; // pedantic-warning{{address of an expression of type 'void'}}
 }
+
+__attribute__((weak)) const unsigned int test10_bound = 10;
+char test10_global[test10_bound]; // all-error {{variable length array declaration not allowed at file scope}}
+void test10(void) {
+  char test10_local[test10_bound] = "help"; // all-error {{variable-sized object may not be initialized}}
+}