From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Mon, 17 Oct 2011 05:48:07 +0000 (+0000)
Subject: Perform an lvalue-to-rvalue conversion on an array index in a __builtin_offsetof... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d82e5d30930f80a92c1270e270fdb475e3718d25;p=clang

Perform an lvalue-to-rvalue conversion on an array index in a __builtin_offsetof expression.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142179 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 83002d5695..ddcbb6d6b1 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -8383,10 +8383,14 @@ ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
         return ExprError(Diag(Idx->getLocStart(),
                               diag::err_typecheck_subscript_not_integer)
                          << Idx->getSourceRange());
+
+      ExprResult IdxRvalue = DefaultLvalueConversion(Idx);
+      if (IdxRvalue.isInvalid())
+        return ExprError();
       
       // Record this array index.
       Comps.push_back(OffsetOfNode(OC.LocStart, Exprs.size(), OC.LocEnd));
-      Exprs.push_back(Idx);
+      Exprs.push_back(IdxRvalue.take());
       continue;
     }
     
diff --git a/test/Sema/offsetof.c b/test/Sema/offsetof.c
index 5026193943..46fb515c7f 100644
--- a/test/Sema/offsetof.c
+++ b/test/Sema/offsetof.c
@@ -65,3 +65,7 @@ int test3 = __builtin_offsetof(struct has_bitfields, j); // expected-error{{cann
 
 typedef struct Array { int array[1]; } Array;
 int test4 = __builtin_offsetof(Array, array);
+
+int test5() {
+  return __builtin_offsetof(Array, array[*(int*)0]); // expected-warning{{indirection of non-volatile null pointer}} expected-note{{__builtin_trap}}
+}