Hans Wennborg wrote:
On Sat, May 14, 2016 at 10:44 AM, Nick Lewycky via cfe-commits
<cfe-commits@lists.llvm.org> wrote:
Author: nicholas
Date: Sat May 14 12:44:14 2016
New Revision: 269572
URL: http://llvm.org/viewvc/llvm-project?rev=269572&view=rev
Log:
Warn when a reference is bound to an empty l-value (dereferenced null pointer).
Could this be made to handle return values too? The warning fired on
some code in pdfium, and nearby I found this:
TYPE& ElementAt(int nIndex) {
if (nIndex< 0 || nIndex>= m_nSize) {
return *(TYPE*)NULL;<-- Ooops
}
return ((TYPE*)m_pData)[nIndex];
}
where the warning doesn't fire.
That looks like a bug, we should already catch that case:
int &test1() {
return *(int*)nullptr;
}
struct TYPE {};
TYPE &test2() {
return *(TYPE*)nullptr;
}
clang ref.cc -std=c++11
ref.cc:2:10: warning: binding dereferenced null pointer to reference has
undefined behavior [-Wnull-dereference]
return *(int*)nullptr;
^~~~~~~~~~~~~~
ref.cc:6:10: warning: binding dereferenced null pointer to reference has
undefined behavior [-Wnull-dereference]
return *(TYPE*)nullptr;
^~~~~~~~~~~~~~~
2 warnings generated.
Could you produce a testcase for it?
Nick
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
